ALL LASER USES:LPKF:LASIK:LASER HAIR REMOVEL AND LASER DIODES

LASERDIS TECHNICAL INFORMATION

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Technical information

The standard home video laserdisc is 30 cm (11.81 inches) in diameter and made up of two single-sided aluminum discs layered in plastic. Although appearing similar to compact discs or DVDs, Laserdiscs use analog video stored in the composite domain with analog sound and/or some form of digital audio. However, despite its analog nature, the Laserdisc at its most fundamental level is still recorded as a series of pits and lands much like DVDs and CDs are today.[10] The first Laserdiscs featured in 1978 were entirely analog but the format evolved to incorporate digital stereo sound in CD format (sometimes with a TOSlink or coax output to feed an external DAC), and later multi-channel formats such as Dolby Digital and DTS.
Since digital encoding and compression schemes were either unavailable or impractical in 1978, three encoding formats based on the rotation speed were used:
CAV (Constant Angular Velocity) or Standard Play discs supported several unique features such as freeze frame, variable slow motion and reverse. CAV discs were spun at a constant rotational speed during playback, with one video frame read per revolution and in this mode, 54,000 individual frames or 30 minutes of audio/video could be stored on a single side of a CAV disc. Another unique attribute to CAV was to reduce the visibility of crosstalk from adjacent tracks, since on CAV discs any crosstalk at a specific point in a frame is simply from the same point in the next or previous frame. CAV was used less frequently than CLV, reserved for special editions of feature films to highlight bonus material and special effects. One of the most intriguing advantages of this format was the ability to reference every frame of a film directly by number—a feature of particular interest to film buffs, students and others intrigued by the study of errors in staging, continuity, etc.
CLV (Constant Linear Velocity) or Extended Play discs do not have the "trick play" features of CAV, offering only simple playback on all but the high-end Laserdisc players incorporating a digital frame store. These high-end Laserdisc players could add features not normally available to CLV discs such as variable forward and reverse, and a VCR-like "pause". CLV encoded discs could store 60 minutes of audio/video per side, or 2 hours per disc. For films with a run–time less than 120 minutes, this meant they could fit on a single disc, lowering the cost of the title and eliminating the distracting exercise of "getting up to change the disc"—at least for those who owned a dual-sided player. The vast majority of titles were only available in CLV. (A few titles were released partly CLV, partly CAV. For example, a 140-minute movie could fit on two CLV sides, and one CAV side, thus allowing for the CAV-only features during the climax of the film.)
CAA (Constant Angular Acceleration). In the early 1980s, due to problems with crosstalk distortion on CLV extended play Laserdiscs, Pioneer Video introduced CAA formatting for extended play discs. Constant Angular Acceleration is very similar to Constant Linear Velocity save for the fact that CAA varies the angular rotation of the disc in controlled steps instead of gradually slowing down in a steady linear pace as a CLV disc is read. With the exception of 3M/Imation, all Laserdisc manufacturers adopted the CAA encoding scheme, although the term was rarely (if ever) used on any consumer packaging.
As Pioneer introduced Digital Audio to Laserdisc in 1985, they further refined the CAA format. CAA55 was introduced in 1985 with a total playback capacity of 55 minutes 5 seconds, and was necessary to resolve technical issues with the inclusion of Digital Audio. Several titles released between 1985 and 1987 were analog audio only due to the length of the title and the desire to keep the film on 1 disc (e.g., "Back to the Future"). By 1987, Pioneer had overcome the technical challenges and was able to once again encode in CAA60—allowing a total of 60 minutes, 5 seconds. Pioneer further refined CAA, offering CAA45—encoding 45 minutes of material, but filling the entire playback surface of the side. Used on only a handful of titles, CAA65 offered 65 minutes 5 seconds of playback time. The final variant of CAA is CAA70, which could accommodate 70 minutes of playback time. There are not any known uses of this format on the consumer market.

History OF LASERDISC

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Laserdisc technology, using a transparent disc,[1] was invented by David Paul Gregg in 1958 (and patented in 1961 and 1990).[2][3] By 1969 Philips had developed a videodisc in reflective mode, which has great advantages over the transparent mode. MCA and Philips decided to join their efforts. They first publicly demonstrated the videodisc in 1972. Laserdisc was first available on the market, in Atlanta, on December 15, 1978, two years after the VHS VCR and four years before the CD, which is based on Laserdisc technology. Philips produced the players and MCA the discs. The Philips/MCA cooperation was not successful, and discontinued after a few years. Several of the scientists responsible for the early research (Richard Wilkinson, Ray Dakin and John Winslow) founded Optical Disc Corporation (now ODC Nimbus).
In 1979, the Museum of Science and Industry in Chicago opened their "Newspaper" exhibit which used interactive Laserdiscs to allow visitors to search for the front page of any Chicago Tribune newspaper. This was a very early use of digitally interactive technology in museums and could even be among the first.[citation needed]
The first Laserdisc title marketed in North America was the MCA DiscoVision release of Jaws in 1978. The last two titles released in North America were Paramount's Sleepy Hollow and Bringing Out the Dead in 2000. The last Hong Kong-released Laserdisc format-movie was Tokyo Raiders. A dozen or so more titles continued to be released in Japan, until the end of 2001. Production of Laserdisc players continued until January 14, 2009 when Pioneer stopped making them.[4][5][6]
It was estimated that in 1998, Laserdisc players were in approximately 2% of US households (roughly two million).[7] By comparison, in 1999, players were in 10% of Japanese households.[8] Laserdisc was released on June 10, 1981 and a total of 3.6 million Laserdisc players were sold in Japan.[9] A total of 16.8 million Laserdisc players were sold worldwide of which 9.5 million of them were sold by Pioneer.[4][5][6]
Laserdisc has been completely replaced by DVD in the North American retail marketplace, as neither players nor software are now produced there. Laserdisc has retained some popularity among American collectors and, to a greater degree, in Japan, where the format was better supported and more prevalent during its life. In Europe, the Laserdisc has always remained an obscure format. The format was, however, chosen by the British Broadcasting Corporation (BBC) for the BBC Domesday Project in the mid-1980s, a school-based project to commemorate 900 years since the original Domesday Book in England.

Laserdisc

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The Laserdisc (LD) is an obsolete home video disc format, and was the first commercial optical disc storage medium. Initially marketed as Discovision in 1978, the technology was licensed and sold as Reflective Optical Videodisc, Laser Videodisc, Laservision, Disco-Vision, DiscoVision, and MCA DiscoVision until Pioneer Electronics purchased the majority stake in the format and marketed LaserDisc in the mid to late 1980s.
While LaserDisc produced a consistently higher quality image than its rivals, the VHS and Betamax systems, the laserdisc never obtained more than a niche market with videophiles in America. In Europe, it remained largely an obscure format. It was, however, much more popular in Japan and in the more affluent regions of South East Asia, such as Hong Kong and Singapore. Laserdisc was the prevalent rental video medium in Hong Kong during the 1990s.
The technology and concepts provided with the Laserdisc would become the forerunner to Compact Discs and DVDs.

X-ray

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When X-rays of sufficient frequency (energy) interact with a substance, inner shell electrons in the atom are excited to outer empty orbitals, or they may be removed completely, ionizing the atom. The inner shell "hole" will then be filled by electrons from outer orbitals. The energy available in this de-excitation process is emitted as radiation (fluorescence) or will remove other less-bound electrons from the atom (Auger effect). The absorption or emission frequencies (energies) are characteristic of the specific atom. In addition, for a specific atom small frequency (energy) variations occur which are characteristic of the chemical bonding. With a suitable apparatus, these characteristic X-ray frequencies or Auger electron energies can be measured. X-ray absorption and emission spectroscopy is used in chemistry and material sciences to determine elemental composition and chemical bonding.
X-ray crystallography is a scattering process; crystalline materials scatter X-rays at well-defined angles. If the wavelength of the incident X-rays is known, this allows calculation of the distances between planes of atoms within the crystal. The intensities of the scattered X-rays give information about the atomic positions and allow the arrangement of the atoms within the crystal structure to be calculated.

Spectroscopy

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Spectroscopy was originally the study of the interaction between radiation and matter as a function of wavelength (λ). In fact, historically, spectroscopy referred to the use of visible light dispersed according to its wavelength, e.g. by a prism. Later the concept was expanded greatly to comprise any measurement of a quantity as function of either wavelength or frequency. Thus it also can refer to a response to an alternating field or varying frequency (ν). A further extension of the scope of the definition added energy (E) as a variable, once the very close relationship E = hν for photons was realized (h is the Planck constant). A plot of the response as a function of wavelength—or more commonly frequency—is referred to as a spectrum; see also spectral linewidth.
Spectrometry is the spectroscopic technique used to assess the concentration or amount of a given species. In this case, the instrument that performs such measurements is a spectrometer or spectrograph.
Spectroscopy/spectrometry is often used in physical and analytical chemistry for the identification of substances through the spectrum emitted from or absorbed by them.
Spectroscopy/spectrometry is also heavily used in astronomy and remote sensing. Most large telescopes have spectrometers, which are used either to measure the chemical composition and physical properties of astronomical objects or to measure their velocities from the Doppler shift of their spectral lines.

Semiconductor lasers

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Semiconductor lasers are also solid-state lasers but have a different mode of laser operation.
Commercial laser diodes emit at wavelengths from 375 nm to 1800 nm, and wavelengths of over 3 µm have been demonstrated. Low power laser diodes are used in laser printers and CD/DVD players. More powerful laser diodes are frequently used to optically pump other lasers with high efficiency. The highest power industrial laser diodes, with power up to 10 kW (70dBm), are used in industry for cutting and welding. External-cavity semiconductor lasers have a semiconductor active medium in a larger cavity. These devices can generate high power outputs with good beam quality, wavelength-tunable narrow-linewidth radiation, or ultrashort laser pulses.

A 5.6 mm 'closed can' commercial laser diode, probably from a CD or DVD player.
Vertical cavity surface-emitting lasers (VCSELs) are semiconductor lasers whose emission direction is perpendicular to the surface of the wafer. VCSEL devices typically have a more circular output beam than conventional laser diodes, and potentially could be much cheaper to manufacture. As of 2005, only 850 nm VCSELs are widely available, with 1300 nm VCSELs beginning to be commercialized,[19] and 1550 nm devices an area of research. VECSELs are external-cavity VCSELs. Quantum cascade lasers are semiconductor lasers that have an active transition between energy sub-bands of an electron in a structure containing several quantum wells.
The development of a silicon laser is important in the field of optical computing. Silicon is the material of choice for integrated circuits, and so electronic and silicon photonic components (such as optical interconnects) could be fabricated on the same chip. Unfortunately, silicon is a difficult lasing material to deal with, since it has certain properties which block lasing. However, recently teams have produced silicon lasers through methods such as fabricating the lasing material from silicon and other semiconductor materials, such as indium(III) phosphide or gallium(III) arsenide, materials which allow coherent light to be produced from silicon. These are called hybrid silicon laser. Another type is a Raman laser, which takes advantage of Raman scattering to produce a laser from materials such as silicon.

Fiber-hosted lasers

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Solid-state lasers where the light is guided due to the total internal reflection in an optical fiber are called fiber lasers. Guiding of light allows extremely long gain regions providing good cooling conditions; fibers have high surface area to volume ratio which allows efficient cooling. In addition, the fiber's waveguiding properties tend to reduce thermal distortion of the beam. Erbium and ytterbium ions are common active species in such lasers.
Quite often, the fiber laser is designed as a double-clad fiber. This type of fiber consists of a fiber core, an inner cladding and an outer cladding. The index of the three concentric layers is chosen so that the fiber core acts as a single-mode fiber for the laser emission while the outer cladding acts as a highly multimode core for the pump laser. This lets the pump propagate a large amount of power into and through the active inner core region, while still having a high numerical aperture (NA) to have easy launching conditions.
Pump light can be used more efficiently by creating a fiber disk laser, or a stack of such lasers.
Fiber lasers have a fundamental limit in that the intensity of the light in the fiber cannot be so high that optical nonlinearities induced by the local electric field strength can become dominant and prevent laser operation and/or lead to the material destruction of the fiber. This effect is called photodarkening. In bulk laser materials, the cooling is not so efficient, and it is difficult to separate the effects of photodarkening from the thermal effects, but the experiments in fibers show that the photodarkening can be attributed to the formation of long-living color centers

LASER MODE OF OPERATIONS

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Modes of operation
The output of a laser may be a continuous constant-amplitude output (known as CW or continuous wave); or pulsed, by using the techniques of Q-switching, modelocking, or gain-switching. In pulsed operation, much higher peak powers can be achieved.
Some types of lasers, such as dye lasers and vibronic solid-state lasers can produce light over a broad range of wavelengths; this property makes them suitable for generating extremely short pulses of light, on the order of a few femtoseconds (10-15 s).
Continuous wave operation
In the continuous wave (CW) mode of operation, the output of a laser is relatively constant with respect to time. The population inversion required for lasing is continually maintained by a steady pump source.
Pulsed operation
In the pulsed mode of operation, the output of a laser varies with respect to time, typically taking the form of alternating 'on' and 'off' periods. In many applications one aims to deposit as much energy as possible at a given place in as short time as possible. In laser ablation for example, a small volume of material at the surface of a work piece might evaporate if it gets the energy required to heat it up far enough in very short time. If, however, the same energy is spread over a longer time, the heat may have time to disperse into the bulk of the piece, and less material evaporates. There are a number of methods to achieve this.
Q-switching
Main article: Q-switching
In a Q-switched laser, the population inversion (usually produced in the same way as CW operation) is allowed to build up by making the cavity conditions (the 'Q') unfavorable for lasing. Then, when the pump energy stored in the laser medium is at the desired level, the 'Q' is adjusted (electro- or acousto-optically) to favourable conditions, releasing the pulse. This results in high peak powers as the average power of the laser (were it running in CW mode) is packed into a shorter time frame.

LASER PHYSICS

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LASER DESIGN

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A laser consists of a gain medium inside a highly reflective optical cavity, as well as a means to supply energy to the gain medium. The gain medium is a material with properties that allow it to amplify light by stimulated emission. In its simplest form, a cavity consists of two mirrors arranged such that light bounces back and forth, each time passing through the gain medium. Typically one of the two mirrors, the output coupler, is partially transparent. The output laser beam is emitted through this mirror.
Light of a specific wavelength that passes through the gain medium is amplified (increases in power); the surrounding mirrors ensure that most of the light makes many passes through the gain medium, being amplified repeatedly. Part of the light that is between the mirrors (that is, within the cavity) passes through the partially transparent mirror and escapes as a beam of light.
The process of supplying the energy required for the amplification is called pumping. The energy is typically supplied as an electrical current or as light at a different wavelength. Such light may be provided by a flash lamp or perhaps another laser. Most practical lasers contain additional elements that affect properties such as the wavelength of the emitted light and the shape of the beam.

LASER TERMINOLOGY

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The word laser was originally spelled LASER and is an acronym for light amplification by stimulated emission of radiation. The word light in this phrase is used in the broader sense, referring to electromagnetic radiation of any frequency, not just that in the visible spectrum. Hence there are infrared lasers, ultraviolet lasers, X-ray lasers, etc. Because the microwave equivalent of the laser, the maser, was developed first, devices that emit microwave and radio frequencies are usually called masers. In early literature, particularly from researchers at Bell Telephone Laboratories, the laser was often called the optical maser. This usage has since become uncommon, and as of 1998 even Bell Labs uses the term laser.[2]
The back-formed verb to lase means "to produce laser light" or "to apply laser light to."[3] The word "laser" is sometimes used to describe other non-light technologies. For example, a source of atoms in a coherent state is called an "atom laser."

LASER

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A laser is a device that emits light (electromagnetic radiation) through a process called stimulated emission. Laser light is usually spatially coherent, which means that the light either is emitted in a narrow, low-divergence beam, or can be converted into one with the help of optical components such as lenses. More generally, coherent light typically means the source produces light waves that are in step. They have the same frequencies and identical phase[1]. The coherence of typical laser emission is a distinctive characteristic of lasers. Most other light sources emit incoherent light, which has a phase that varies randomly with time and position. Typically, lasers are thought of as emitting light with a narrow wavelength spectrum ("monochromatic" light). This is not true of all lasers, however: some emit light with a broad spectrum, while others emit light at multiple distinct wavelengths simultaneously.

Laser printer maintenance

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Most consumer and small business laser printers use a toner cartridge that combines the photoreceptor (sometimes called "photoconductor unit" or "imaging drum") with the toner supply bin, the waste toner hopper, and various wiper blades. When the toner supply is consumed, replacing the toner cartridge automatically replaces the imaging drum, waste toner hopper, and wiper blades.
Some laser printers maintain a page count of the number of pages printed since last maintenance. On these models, a reminder message will appear informing the user it is nearing time to replace standard maintenance parts. On other models, no page count is kept or no reminder is displayed, so the user must keep track of pages printed manually or watch for warning signs like paper feed problems and print defects.
Manufacturers usually provide life expectancy charts for common printer parts and consumables. Manufacturers rate life expectancy for their printer parts in terms of "expected page-production life" rather than in units of time.
Consumables and maintenance parts for Business-class printers will generally be rated for a higher page-production expectancy than parts for personal printers. In particular, toner cartridges and fusers usually have a higher page production expectancy in business-class printers than personal-class printers. Color laser printers can require more maintenance and parts replacement than monochrome laser printers since they contain more imaging components.
For rollers and assemblies involved in the paper pickup path and paper feed path, typical maintenance is to vacuum toner and dust from the mechanisms, and replace, clean, or restore the rubber paper-handling rollers. Most pickup, feed, and separation rollers have a rubber coating which eventually suffers wear and becomes covered with slippery paper dust. In cases where replacement rollers are discontinued or unavailable, rubber rollers can be cleaned safely with a damp lint-free rag. Commercial chemical solutions are also available which may help temporarily restore the traction of the rubber.
The fusing assembly (also called a "fuser") is generally considered a replaceable consumable part on laser printers. The fusing assembly is responsible for melting and bonding the toner to the paper. There are many possible defects for fusing assemblies: defects include worn plastic drive gears, electronic failure of heating components, torn fixing film sleeves, worn pressure rollers, toner buildup on heating rollers and pressure rollers, worn or scratched pressure rollers, and damaged paper sensors.
Some manufacturers offer preventative maintenance kits specific to each printer model; such kits generally include a fuser and may also include pickup rollers, feed rollers, transfer rollers, charge rollers, and separation pads.

color laser printers

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Color laser printers use colored toner (dry ink), typically cyan, magenta, yellow, and black (CMYK).
While monochrome printers only use one laser scanner assembly, color printers often have two or more scanner assemblies.
Color printing adds complexity to the printing process because very slight misalignments known as registration errors can occur between printing each color, causing unintended color fringing, blurring, or light/dark streaking along the edges of colored regions. To permit a high registration accuracy, some color laser printers use a large rotating belt called a "transfer belt". The transfer belt passes in front of all the toner cartridges and each of the toner layers are precisely applied to the belt. The combined layers are then applied to the paper in a uniform single step.
Color printers usually have a higher "cents-per-page" production cost than monochrome printers.
DPI Resolution

1200 DPI printers are commonly available during 2008.
2400 DPI electrophotographic printing plate makers, essentially laser printers that print on plastic sheets, are also available.

developing of laser printers

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How it works

Main article: Xerography
There are typically seven steps involved in the laser printing process:
[edit]Raster image processing

Generating the raster image data
Each horizontal strip of dots across the page is known as a raster line or scan line. Creating the image to be printed is done by a Raster Image Processor (RIP), typically built into the laser printer. The source material may be encoded in any number of special page description languages such as Adobe PostScript (PS) , HP Printer Command Language (PCL), or Microsoft XML Page Specification (XPS) , as well as unformatted text-only data. The RIP uses the page description language to generate a bitmap of the final page in the raster memory. Once the entire page has been rendered in raster memory, the printer is ready to begin the process of sending the rasterized stream of dots to the paper in a continuous stream.
[edit]Charging

Applying a negative charge to the photosensitive drum
A corona wire (in older printers) or a primary charge roller projects an electrostatic charge onto the photoreceptor (otherwise named the photoconductor unit), a revolving photosensitive drum or belt, which is capable of holding an electrostatic charge on its surface while it is in the dark.
An AC bias is applied to the primary charge roller to remove any residual charges left by previous images. The roller will also apply a DC bias on the drum surface to ensure a uniform negative potential. The desired print density is modulated by this DC bias. [4]
Numerous patents describe the photosensitive drum coating as a silicon sandwich with a photocharging layer, a charge leakage barrier layer, as well as a surface layer. One version uses amorphous silicon containing hydrogen as the light receiving layer, Boron nitride as a charge leakage barrier layer, as well as a surface layer of doped silicon, notably silicon with oxygen or nitrogen which at sufficient concentration resembles machining silicon nitride; the effect is that of a light chargeable diode with minimal leakage and a resistance to scuffing.

working of laser printers

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history of laser printers

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History

Gary Starkweather, inventor of the laser printer, in 2009.
The laser printer was invented at Xerox in 1969 by researcher Gary Starkweather, who had an improved printer working by 1971[1] and incorporated into a fully functional networked printer system by about a year later.[2] The prototype was built by modifying an existing xerographic copier. Starkweather disabled the imaging system and created a spinning drum with 8 mirrored sides, with a laser focused on the drum. Light from the laser would bounce off the spinning drum, sweeping across the page as it traveled through the copier. The hardware was completed in just a week or two, but the computer interface and software took almost 3 months to complete.[citation needed]
The first commercial implementation of a laser printer was the IBM model 3800 in 1976, used for high-volume printing of documents such as invoices and mailing labels. It is often cited as "taking up a whole room," implying that it was a primitive version of the later familiar device used with a personal computer. While large, it was designed for an entirely different purpose. Many 3800s are still in use.[citation needed]
The first laser printer designed for use with an office setting was released as the Xerox Star 8010 in 1981. Although it was innovative, the Star was an expensive ($17,000) system that was purchased by only a relatively small number of businesses and institutions. After personal computers became more widespread, the first laser printer intended for a mass market was the HP LaserJet 8ppm, released in 1984, using a Canon engine controlled by HP software. The HP LaserJet printer was quickly followed by laser printers from Brother Industries, IBM, and others. First-generation machines had large photosensitive drums, of circumference greater than the paper length. Once faster-recovery coatings were developed, the drums could touch the paper multiple times in a pass, and could therefore be smaller in diameter.

As with most electronic devices, the cost of laser printers has fallen markedly over the years. In 1984, the HP LaserJet sold for $3500[3], had trouble with even small, low resolution graphics, and weighed 71 pounds (32 kg). Low end monochrome laser printers often sell for less than $75 as of 2008. These printers tend to lack onboard processing and rely on the host computer to generate a raster image (see Winprinter), but still will outperform the LaserJet Classic in nearly all situations.

laser printers advantage

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Laser printers have many significant advantages over other types of printers. Unlike impact printers, laser printer speed can vary widely, and depends on many factors, including the graphic intensity of the job being processed. The fastest models can print over 200 monochrome pages per minute (12,000 pages per hour). The fastest color laser printers can print over 100 pages per minute (6000 pages per hour). Very high-speed laser printers are used for mass mailings of personalized documents, such as credit card or utility bills, and are competing with lithography in some commercial applications.
The cost of this technology depends on a combination of factors, including the cost of paper, toner, and infrequent drum replacement, as well as the replacement of other consumables such as the fuser assembly and transfer assembly. Often printers with soft plastic drums can have a very high cost of ownership that does not become apparent until the drum requires replacement.
A duplexing printer (one that prints on both sides of the paper) can halve paper costs and reduce filing volumes. Formerly only available on high-end printers, duplexers are now common on mid-range office printers, though not all printers can accommodate a duplexing unit. Duplexing can also give a slower page-printing speed, because of the longer paper path.
In comparison with the laser printer, most inkjet printers and dot-matrix printers simply take an incoming stream of data and directly imprint it in a slow lurching process that may include pauses as the printer waits for more data. A laser printer is unable to work this way because such a large amount of data needs to output to the printing device in a rapid, continuous process. The printer cannot stop the mechanism precisely enough to wait until more data arrives, without creating a visible gap or misalignment of the dots on the printed page.
Instead the image data is built up and stored in a large bank of memory capable of representing every dot on the page. The requirement to store all dots in memory before printing has traditionally limited laser printers to small fixed paper sizes such as letter or A4. Most laser printers are unable to print continuous banners spanning a sheet of paper two meters long, because there is not enough memory available in the printer to store such a large image before printing begins.

laser printers

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A laser printer is a common type of computer printer that rapidly produces high quality text and graphics on plain paper. As with digital photocopiers and multifunction printers (MFPs), laser printers employ a xerographic printing process but differ from analog photocopiers in that the image is produced by the direct scanning of a laser beam across the printer's photoreceptor.
Overview

A laser beam projects an image of the page to be printed onto an electrically charged rotating drum coated with selenium. Photoconductivity removes charge from the areas exposed to light. Dry ink (toner) particles are then electrostatically picked up by the drum's charged areas. The drum then prints the image onto paper by direct contact and heat, which fuses the ink to the paper.

laser Fictional predictions

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For lasers in fiction, see also the ray gun.
Before stimulated emission was discovered, novelists used to describe machines that we can identify as "lasers".
A laser-like device was described in Alexey Tolstoy's sci-fi novel The Hyperboloid of Engineer Garin in 1927.
Mikhail Bulgakov exaggerated the biological effect (laser bio stimulation) of intensive red light in his sci-fi novel Fatal Eggs (1925), without any reasonable description of the source of this red light. (In that novel, the red light first appears occasionally from the illuminating system of an advanced microscope; then the protagonist Prof. Persikov arranges the special set-up for generation of the red light.)

Lasers as weapons

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Laser beams are famously employed as weapon systems in science fiction, but actual laser weapons are only beginning to enter the market. The general idea of laser-beam weaponry is to hit a target with a train of brief pulses of light. The rapid evaporation and expansion of the surface causes shockwaves that damage the target.
The power needed to project a high-powered laser beam of this kind is difficult for current mobile power technology. Public prototypes are chemically-powered gas dynamic lasers.
Lasers of all but the lowest powers can potentially be used as incapacitating weapons, through their ability to produce temporary or permanent vision loss in varying degrees when aimed at the eyes. The degree, character, and duration of vision impairment caused by eye exposure to laser light varies with the power of the laser, the wavelength(s), the collimation of the beam, the exact orientation of the beam, and the duration of exposure. Lasers of even a fraction of a watt in power can produce immediate, permanent vision loss under certain conditions, making such lasers potential non-lethal but incapacitating weapons. The extreme handicap that laser-induced blindness represents makes the use of lasers even as non-lethal weapons morally controversial.
In the field of aviation, the hazards of exposure to ground-based lasers deliberately aimed at pilots have grown to the extent that aviation authorities have special procedures to deal with such hazards.[32]
On March 18, 2009 Northrop Grumman announced that its engineers in Redondo Beach had successfully built and tested an electric laser capable of producing a 100-kilowatt ray of light, powerful enough to destroy an airplane or a tank. An electric laser is theoretically capable, according to Brian Strickland, manager for the United States Army's Joint High Power Solid State Laser program, of being mounted in an aircraft, ship, or vehicle because it requires much less space for its supporting equipment than a chemical laser.[33]
Applications

In manufacturing, lasers are used for cutting, bending, and welding metal and other materials, and for "marking"—producing visible patterns such as letters by changing the properties of a material or by inscribing its surface. In science, lasers are used for many applications. One of the more common is laser spectroscopy, which typically takes advantage of the laser's well-defined wavelength or the possibility of generating very short pulses of light. Lasers are used by the military for range-finding, target designation, and illumination. Lasers have also begun to be tested for directed-energy weapons. Lasers are used in medicine for surgery, diagnostics, and therapeutic applications.

Laser safety

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Main article: Laser safety
Even the first laser was recognized as being potentially dangerous. Theodore Maiman characterized the first laser as having a power of one "Gillette" as it could burn through one Gillette razor blade. Today, it is accepted that even low-power lasers with only a few milliwatts of output power can be hazardous to human eyesight, when the beam from such a laser hits the eye directly or after reflection from a shiny surface. At wavelengths which the cornea and the lens can focus well, the coherence and low divergence of laser light means that it can be focused by the eye into an extremely small spot on the retina, resulting in localized burning and permanent damage in seconds or even less time.
Lasers are usually labeled with a safety class number, which identifies how dangerous the laser is:
Class I/1 is inherently safe, usually because the light is contained in an enclosure, for example in CD players.
Class II/2 is safe during normal use; the blink reflex of the eye will prevent damage. Usually up to 1 mW power, for example laser pointers.
Class IIIa/3R lasers are usually up to 5 mW and involve a small risk of eye damage within the time of the blink reflex. Staring into such a beam for several seconds is likely to cause (minor) eye damage.
Class IIIb/3B can cause immediate severe eye damage upon exposure. Usually lasers up to 500 mW, such as those in CD and DVD writers.
Class IV/4 lasers can burn skin, and in some cases, even scattered light can cause eye and/or skin damage. Many industrial and scientific lasers are in this class.
The indicated powers are for visible-light, continuous-wave lasers. For pulsed lasers and invisible wavelengths, other power limits apply. People working with class 3B and class 4 lasers can protect their eyes with safety goggles which are designed to absorb light of a particular wavelength.
Certain infrared lasers with wavelengths beyond about 1.4 micrometres are often referred to as being "eye-safe". This is because the intrinsic molecular vibrations of water molecules very strongly absorb light in this part of the spectrum, and thus a laser beam at these wavelengths is attenuated so completely as it passes through the eye's cornea that no light remains to be focused by the lens onto the retina. The label "eye-safe" can be misleading, however, as it only applies to relatively low power continuous wave beams and any high power or Q-switched laser at these wavelengths can burn the cornea, causing severe eye damage.

laser Hobby uses

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In recent years, some hobbyists have taken interests in lasers. Lasers used by hobbyists are generally of class IIIa or IIIb, although some have made their own class IV types.[30] However, compared to other hobbyists, laser hobbyists are far less common, due to the cost and potential dangers involved. Due to the cost of lasers, some hobbyists use inexpensive means to obtain lasers, such as extracting diodes from DVD burners.[31]
Hobbyists also have been taking surplus pulsed lasers from retired military applications and modifying them for pulsed holography. Pulsed Ruby and Pulsed YAG lasers have been used.

Examples by power

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Different uses need lasers with different output powers. Lasers that produce a continuous beam or a series of short pulses can be compared on the basis of their average power. Lasers that produce pulses can also be characterized based on the peak power of each pulse. The peak power of a pulsed laser is many orders of magnitude greater than its average power. The average output power is always less than the power consumed.
The continuous or average power required for some uses:
less than 1 mW – laser pointers
5 mW – CD-ROM drive
5–10 mW – DVD player or DVD-ROM drive
100 mW – High-speed CD-RW burner
250 mW – Consumer DVD-R burner
1 W – green laser in current Holographic Versatile Disc prototype development
1–20 W – output of the majority of commercially available solid-state lasers used for micro machining
30–100 W – typical sealed CO2 surgical lasers[26]
100–3000 W (peak output 1.5 kW) – typical sealed CO2 lasers used in industrial laser cutting
1 kW – Output power expected to be achieved by a prototype 1 cm diode laser bar[27]
Examples of pulsed systems with high peak power:
700 TW (700×1012 W) – National Ignition Facility, a 192-beam, 1.8-megajoule laser system adjoining a 10-meter-diameter target chamber.[28]
1.3 PW (1.3×1015 W) – world's most powerful laser as of 1998, located at the Lawrence Livermore Laboratory[29]

ALL LASER USES

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Main article: Laser applications
When lasers were invented in 1960, they were called "a solution looking for a problem".[23] Since then, they have become ubiquitous, finding utility in thousands of highly varied applications in every section of modern society, including consumer electronics, information technology, science, medicine, industry, law enforcement, entertainment, and the military.
The first application of lasers visible in the daily lives of the general population was the supermarket barcode scanner, introduced in 1974. The laserdisc player, introduced in 1978, was the first successful consumer product to include a laser, but the compact disc player was the first laser-equipped device to become truly common in consumers' homes, beginning in 1982, followed shortly by laser printers.
Some of the other applications include:
Medicine: Bloodless surgery, laser healing, surgical treatment, kidney stone treatment, eye treatment, dentistry
Industry: Cutting, welding, material heat treatment, marking parts
Defense: Marking targets, guiding munitions, missile defence, electro-optical countermeasures (EOCM), alternative to radar, blinding enemy troops.
Research: Spectroscopy, laser ablation, Laser annealing, laser scattering, laser interferometry, LIDAR, Laser capture microdissection
Product development/commercial: laser printers, CDs, barcode scanners, thermometers, laser pointers, holograms, bubblegrams.
Laser lighting displays: Laser light shows
Laser skin procedures such as acne treatment, cellulite reduction, and hair removal.
In 2004, excluding diode lasers, approximately 131,000 lasers were sold worldwide, with a value of US$2.19 billion.[24] In the same year, approximately 733 million diode lasers, valued at $3.20 billion, were sold.[25]

Exotic laser media

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In September 2007, the BBC News reported that there was speculation about the possibility of using positronium annihilation to drive a very powerful gamma ray laser.[20] Dr. David Cassidy of the University of California, Riverside proposed that a single such laser could be used to ignite a nuclear fusion reaction, replacing the hundreds of lasers used in typical inertial confinement fusion experiments.[20]
Space-based X-ray lasers pumped by a nuclear explosion have also been proposed as antimissile weapons.[21][22] Such devices would be one-shot weapons.

Free electron lasers

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Free electron lasers, or FELs, generate coherent, high power radiation, that is widely tunable, currently ranging in wavelength from microwaves, through terahertz radiation and infrared, to the visible spectrum, to soft X-rays. They have the widest frequency range of any laser type. While FEL beams share the same optical traits as other lasers, such as coherent radiation, FEL operation is quite different. Unlike gas, liquid, or solid-state lasers, which rely on bound atomic or molecular states, FELs use a relativistic electron beam as the lasing medium, hence the term free electron.

Dye lasers

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Dye lasers use an organic dye as the gain medium. The wide gain spectrum of available dyes allows these lasers to be highly tunable, or to produce very short-duration pulses (on the order of a few femtoseconds)

Semiconductor lasers

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Photonic crystal lasers

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Photonic crystal lasers are lasers based on nano-structures that provide the mode confinement and the density of optical states (DOS) structure required for the feedback to take place[clarification needed]. They are typical micrometre-sized and tunable on the bands of the photonic crystals. [2][clarification needed]

Fiber-hosted lasers

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Solid-state lasers

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Solid-state laser materials are commonly made by "doping" a crystalline solid host with ions that provide the required energy states. For example, the first working laser was a ruby laser, made from ruby (chromium-doped corundum). The population inversion is actually maintained in the "dopant", such as chromium or neodymium. Formally, the class of solid-state lasers includes also fiber laser, as the active medium (fiber) is in the solid state. Practically, in the scientific literature, solid-state laser usually means a laser with bulk active medium, while wave-guide lasers are caller fiber lasers.
"Semiconductor lasers" are also solid-state lasers, but in the customary laser terminology, "solid-state laser" excludes semiconductor lasers, which have their own name.
Neodymium is a common "dopant" in various solid-state laser crystals, including yttrium orthovanadate (Nd:YVO4), yttrium lithium fluoride (Nd:YLF) and yttrium aluminium garnet (Nd:YAG). All these lasers can produce high powers in the infrared spectrum at 1064 nm. They are used for cutting, welding and marking of metals and other materials, and also in spectroscopy and for pumping dye lasers. These lasers are also commonly frequency doubled, tripled or quadrupled to produce 532 nm (green, visible), 355 nm (UV) and 266 nm (UV) light when those wavelengths are needed.
Ytterbium, holmium, thulium, and erbium are other common "dopants" in solid-state lasers. Ytterbium is used in crystals such as Yb:YAG, Yb:KGW, Yb:KYW, Yb:SYS, Yb:BOYS, Yb:CaF2, typically operating around 1020-1050 nm. They are potentially very efficient and high powered due to a small quantum defect. Extremely high powers in ultrashort pulses can be achieved with Yb:YAG. Holmium-doped YAG crystals emit at 2097 nm and form an efficient laser operating at infrared wavelengths strongly absorbed by water-bearing tissues. The Ho-YAG is usually operated in a pulsed mode, and passed through optical fiber surgical devices to resurface joints, remove rot from teeth, vaporize cancers, and pulverize kidney and gall stones.
Titanium-doped sapphire (Ti:sapphire) produces a highly tunable infrared laser, commonly used for spectroscopy as well as the most common ultrashort pulse laser.
Thermal limitations in solid-state lasers arise from unconverted pump power that manifests itself as heat and phonon energy. This heat, when coupled with a high thermo-optic coefficient (dn/dT) can give rise to thermal lensing as well as reduced quantum efficiency. These types of issues can be overcome by another novel diode-pumped solid-state laser, the diode-pumped thin disk laser. The thermal limitations in this laser type are mitigated by using a laser medium geometry in which the thickness is much smaller than the diameter of the pump beam. This allows for a more even thermal gradient in the material. Thin disk lasers have been shown to produce up to kilowatt levels of power.[18]

Excimer lasers

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Excimer lasers are powered by a chemical reaction involving an excited dimer, or excimer, which is a short-lived dimeric or heterodimeric molecule formed from two species (atoms), at least one of which is in an excited electronic state. They typically produce ultraviolet light, and are used in semiconductor photolithography and in LASIK eye surgery. Commonly used excimer molecules include F2 (fluorine, emitting at 157 nm), and noble gas compounds (ArF [193 nm], KrCl [222 nm], KrF [248 nm], XeCl [308 nm], and XeF [351 nm]).[17]

Chemical lasers

2009-11-02T08:56:00.001-08:00

Chemical lasers are powered by a chemical reaction, and can achieve high powers in continuous operation. For example, in the Hydrogen fluoride laser (2700-2900 nm) and the Deuterium fluoride laser (3800 nm) the reaction is the combination of hydrogen or deuterium gas with combustion products of ethylene in nitrogen trifluoride. They were invented by George C. Pimentel.

Types and operating principles

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Gas lasers
Gas lasers using many gases have been built and used for many purposes.
The helium-neon laser (HeNe) emits at a variety of wavelengths and units operating at 633 nm are very common in education because of its low cost.
Carbon dioxide lasers can emit hundreds of kilowatts[14] at 9.6 µm and 10.6 µm, and are often used in industry for cutting and welding. The efficiency of a CO2 laser is over 10%.
Argon-ion lasers emit light in the range 351-528.7 nm. Depending on the optics and the laser tube a different number of lines is usable but the most commonly used lines are 458 nm, 488 nm and 514.5 nm.
A nitrogen transverse electrical discharge in gas at atmospheric pressure (TEA) laser is an inexpensive gas laser producing UV Light at 337.1 nm.[15]
Metal ion lasers are gas lasers that generate deep ultraviolet wavelengths. Helium-silver (HeAg) 224 nm and neon-copper (NeCu) 248 nm are two examples. These lasers have particularly narrow oscillation linewidths of less than 3 GHz (0.5 picometers),[16] making them candidates for use in fluorescence suppressed Raman spectroscopy.

HISTORY OF LASER

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Foundations
In 1917 Albert Einstein, in his paper Zur Quantentheorie der Strahlung (On the Quantum Theory of Radiation), laid the foundation for the invention of the laser and its predecessor, the maser, in a ground-breaking rederivation of Max Planck's law of radiation based on the concepts of probability coefficients (later to be termed 'Einstein coefficients') for the absorption, spontaneous emission, and stimulated emission of electromagnetic radiation.
In 1928, Rudolf W. Ladenburg confirmed the existence of stimulated emission and negative absorption.[5] In 1939, Valentin A. Fabrikant predicted the use of stimulated emission to amplify "short" waves.[6]
In 1947, Willis E. Lamb and R. C. Retherford found apparent stimulated emission in hydrogen spectra and made the first demonstration of stimulated emission.[7]
In 1950, Alfred Kastler (Nobel Prize for Physics 1966) proposed the method of optical pumping, which was experimentally confirmed by Brossel, Kastler and Winter two years later.[8]
The first working laser was demonstrated on 16 May 1960 by Theodore Maiman at Hughes Research Laboratories.[9] Since then, lasers have become a multi-billion dollar industry. By far the largest single application of lasers is in optical storage devices such as compact disc and DVD players,[citation needed] in which a semiconductor laser less than a millimeter wide scans the surface of the disc. The second-largest application is fiber-optic communication. Other common applications of lasers are bar code readers, laser printers and laser pointers.
Maser
Main article: Maser
In 1953, Charles H. Townes and graduate students James P. Gordon and Herbert J. Zeiger produced the first microwave amplifier, a device operating on similar principles to the laser, but amplifying microwave rather than infrared or visible radiation. Townes's maser was incapable of continuous output. Nikolay Basov and Aleksandr Prokhorov of the Soviet Union worked independently on the quantum oscillator and solved the problem of continuous output systems by using more than two energy levels and produced the first maser. These systems could release stimulated emission without falling to the ground state, thus maintaining a population inversion. In 1955 Prokhorov and Basov suggested an optical pumping of multilevel system as a method for obtaining the population inversion, which later became one of the main methods of laser pumping.
Townes reports that he encountered opposition from a number of eminent colleagues who thought the maser was theoretically impossible—including Niels Bohr, John von Neumann, Isidor Rabi, Polykarp Kusch, and Llewellyn H. Thomas[1].
Townes, Basov, and Prokhorov shared the Nobel Prize in Physics in 1964 "For fundamental work in the field of quantum electronics, which has led to the construction of oscillators and amplifiers based on the maser-laser principle."

LASER Modes of operation

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The output of a laser may be a continuous constant-amplitude output (known as CW or continuous wave); or pulsed, by using the techniques of Q-switching, modelocking, or gain-switching. In pulsed operation, much higher peak powers can be achieved.
Some types of lasers, such as dye lasers and vibronic solid-state lasers can produce light over a broad range of wavelengths; this property makes them suitable for generating extremely short pulses of light, on the order of a few femtoseconds (10-15 s).
Continuous wave operation
In the continuous wave (CW) mode of operation, the output of a laser is relatively constant with respect to time. The population inversion required for lasing is continually maintained by a steady pump source.
Pulsed operation
In the pulsed mode of operation, the output of a laser varies with respect to time, typically taking the form of alternating 'on' and 'off' periods. In many applications one aims to deposit as much energy as possible at a given place in as short time as possible. In laser ablation for example, a small volume of material at the surface of a work piece might evaporate if it gets the energy required to heat it up far enough in very short time. If, however, the same energy is spread over a longer time, the heat may have time to disperse into the bulk of the piece, and less material evaporates. There are a number of methods to achieve this.

Laser physics

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The gain medium of a laser is a material of controlled purity, size, concentration, and shape, which amplifies the beam by the process of stimulated emission. It can be of any state: gas, liquid, solid or plasma. The gain medium absorbs pump energy, which raises some electrons into higher-energy ("excited") quantum states. Particles can interact with light both by absorbing photons or by emitting photons. Emission can be spontaneous or stimulated. In the latter case, the photon is emitted in the same direction as the light that is passing by. When the number of particles in one excited state exceeds the number of particles in some lower-energy state, population inversion is achieved and the amount of stimulated emission due to light that passes through is larger than the amount of absorption. Hence, the light is amplified. By itself, this makes an optical amplifier. When an optical amplifier is placed inside a resonant optical cavity, one obtains a laser.
The light generated by stimulated emission is very similar to the input signal in terms of wavelength, phase, and polarization. This gives laser light its characteristic coherence, and allows it to maintain the uniform polarization and often monochromaticity established by the optical cavity design.
The optical cavity, a type of cavity resonator, contains a coherent beam of light between reflective surfaces so that the light passes through the gain medium more than once before it is emitted from the output aperture or lost to diffraction or absorption. As light circulates through the cavity, passing through the gain medium, if the gain (amplification) in the medium is stronger than the resonator losses, the power of the circulating light can rise exponentially. But each stimulated emission event returns a particle from its excited state to the ground state, reducing the capacity of the gain medium for further amplification. When this effect becomes strong, the gain is said to be saturated. The balance of pump power against gain saturation and cavity losses produces an equilibrium value of the laser power inside the cavity; this equilibrium determines the operating point of the laser. If the chosen pump power is too small, the gain is not sufficient to overcome the resonator losses, and the laser will emit only very small light powers. The minimum pump power needed to begin laser action is called the lasing threshold. The gain medium will amplify any photons passing through it, regardless of direction; but only the photons aligned with the cavity manage to pass more than once through the medium and so have significant amplification.
The beam in the cavity and the output beam of the laser, if they occur in free space rather than waveguides (as in an optical fiber laser), are, at best, low order Gaussian beams. However this is rarely the case with powerful lasers. If the beam is not a low-order Gaussian shape, the transverse modes of the beam can be described as a superposition of Hermite-Gaussian or Laguerre-Gaussian beams (for stable-cavity lasers). Unstable laser resonators on the other hand, have been shown to produce fractal shaped beams.[4] The beam may be highly collimated, that is being parallel without diverging. However, a perfectly collimated beam cannot be created, due to diffraction. The beam remains collimated over a distance which varies with the square of the beam diameter, and eventually diverges at an angle which varies inversely with the beam diameter. Thus, a beam generated by a small laboratory laser such as a helium-neon laser spreads to about 1.6 kilometers (1 mile) diameter if shone from the Earth to the Moon. By comparison, the output of a typical semiconductor laser, due to its small diameter, diverges almost as soon as it leaves the aperture, at an angle of anything up to 50°. However, such a divergent beam can be transformed into a collimated beam by means of a lens. In contrast, the light from non-laser light sources cannot be collimated by optics as well.
Although the laser phenomenon was discovered with the help of quantum physics, it is not essentially more quantum mechanical than other light sources. The operation of a free electron laser can be explained without reference to quantum mechanics.

LASER DESIGNS

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Main article: Laser construction
A laser consists of a gain medium inside a highly reflective optical cavity, as well as a means to supply energy to the gain medium. The gain medium is a material with properties that allow it to amplify light by stimulated emission. In its simplest form, a cavity consists of two mirrors arranged such that light bounces back and forth, each time passing through the gain medium. Typically one of the two mirrors, the output coupler, is partially transparent. The output laser beam is emitted through this mirror.
Light of a specific wavelength that passes through the gain medium is amplified (increases in power); the surrounding mirrors ensure that most of the light makes many passes through the gain medium, being amplified repeatedly. Part of the light that is between the mirrors (that is, within the cavity) passes through the partially transparent mirror and escapes as a beam of light.
The process of supplying the energy required for the amplification is called pumping. The energy is typically supplied as an electrical current or as light at a different wavelength. Such light may be provided by a flash lamp or perhaps another laser. Most practical lasers contain additional elements that affect properties such as the wavelength of the emitted light and the shape of the beam.

Terminology

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ELECTROMAGNETIC RADIATIONS

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IBM Drops Employee Co-Pay for Primary Care Visits

2009-10-30T11:04:00.003-07:00

In what's seen as a highly unusual move, IBM says it will stop requiring employees to shell out a $20 co-payment when they see a primary care physician.

The company says the decision will save costs by encouraging employees to be seen and treated by primary care physicians sooner, thus reducing the likelihood of later expensive visits to emergency departments and specialists, theWall Street Journalreported.

The policy change "is designed to encourage people to get fixed early. .... We'd rather diagnose a situation and deal with it quickly as opposed to it becoming chronic," said Randy MacDonald, senior vice president for human resources.

IBM's decision is "very unusual," said Helen Darling, president of the National Business Group on Health, a trade group representing large employers. "The number of employers who cover primary-physician visits without a co-pay is miniscule," she told theWall Street Journal.

IBM is one of the largest employers in the United States, and its actions sometimes begin new trends.

California Gives $230 Million for Stem Cell Research

2009-10-30T11:04:00.001-07:00

Embryonic stem cells are the focus of only four of 14 projects that received $230 million in grants from California's stem cell research program. The other projects use less controversial adult stem cells or conventional drugs designed to kill cancer stem cells, which are believed to give rise to tumors.

Wednesday's announcement about the funding to state universities and companies is seen as tacit acknowledgement that it will be a long time before the full potential of human embryonic stem cells in treating human diseases is achieved,The New York Timesreported.

Recipients of the grants are supposed to have a therapy ready for initial human testing within four years.

People don't care about what type of stem cells are used as long as researchers find treatments for diseases such as cancer and AIDS, according to officials of the 10-year, $3 billion program that was launched by California in 2004,The Timesreported.

FDA Panel Recommends First Non-Drug Asthma Treatment

2009-10-30T11:03:00.002-07:00

A new technology from a small California-based company should be approved as the first non-drug treatment for asthma, a U.S. Food and Drug Administration advisory panel recommended Wednesday.

Asthmatx's Alair System employs bronchial thermoplasty, which uses radiofrequency wave-generated heat to burn away lung tissue that impairs breathing and causes wheezing and coughing spasms, theAssociated Pressreported.

The radiofrequency waves are delivered via a catheter controlled by a respiratory specialist. The procedure, performed over three sessions of a half hour each, is appropriate only for adult patients with severe asthma that doesn't respond to drug treatment.

The FDA panel voted six to one to recommend approval of the new system under certain conditions, including long-term safety monitoring of patients, theAPreported. The FDA usually follows the advice of its advisory panels.

The Alair System is already approved in Europe. If the FDA does approve the system, it may be available in the United States in the first half of 2010.

Dental Costs Lowest in Georgia and Ohio

2009-10-30T11:03:00.001-07:00

Dental care for people in Georgia and Ohio costs almost $150 less than the U.S. average of $607 a year, says a federal government study released Thursday.

The average annual expenditure for dental care in Georgia was $466, while in Ohio it was $474, said the latestNews and Numbersfrom the Agency for Healthcare Research and Quality.

Among the other findings from the analysis of average annual dental expenditures in the 10 states with the highest populations in 2006:
The highest proportion of residents with dental expenses (52.5 percent) was in Michigan and the lowest was in Texas (30 percent).
The national average for out-of-pocket payment for dental care was 49 percent. People in Florida paid more (62.5 percent) and those in Pennsylvania paid less (42 percent).
Nationally, private insurers paid 43 percent of all dental expenditures.

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Chinese Drywall Contains Higher Chemical Content

Chinese-made drywall has higher amounts of some chemicals than American-made drywall, say U.S. government agencies that have investigated reports of health problems, foul smells and corrosion by owners of homes with the Chinese product.

The Environmental Protection Agency and other departments have analyzed the drywall and say further study is needed to determine if there's a direct link between the problems and the wallboard, theAssociated Pressreported.

During the peak of the U.S. housing boom, materials became scarce, and construction companies imported millions of pounds of Chinese-made drywall, which ended up in thousands of homes.

Methadone Overdose a Danger for Medicaid Patients

2009-10-30T10:58:00.000-07:00

Medicaid patients may be at high risk for overdose death caused by the opioid painkiller methadone, according to a study released Thursday.

The researchers looked at Washington, where the 2006 rate of opioid painkiller overdoses was significantly higher than in the rest of the country. Between 2004 and 2007, 1,668 people in Washington died of prescription opioid-related overdoses. Of those, 58.9 percent were male, 34.4 percent were 45 to 54 years old, and 45.4 percent were Medicaid clients.

The study found that Medicaid clients had a 5.7-fold increased risk of dying from a prescription opioid-related overdose. Methadone was involved in nearly two-thirds of those Medicaid client deaths.

It may be possible to minimize the risk by examining patterns of opioid prescribing to Medicaid clients and intervening with those who appear to misuse the drugs, the researchers concluded.

The study appears in the latestMorbidity and Mortality Report, published by the Centers for Disease Control and Prevention.

Deaths involving prescription opioid painkillers are a major reason why the number of poisoning deaths in the United States nearly doubled from 1999 to 2006.

Vision loss: Introduction

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This section discusses 645 medical conditions causing Vision loss. A simple discussion of these causes with additional information is below.
Central vision loss (see Vision changes) - with possible causes of central vision loss such as:
Blind spot
Cataracts
Macular degeneration
Macular hole
Optic neuritis - may cause unilateral sudden central vision loss.
Multiple sclerosis - because it may cause optic neuritis
Brain tumors
Brain aneurysm

Diabetes increases risk of dementia in elderly

2009-10-30T10:54:00.001-07:00

A Swedish study indicates that diabetes in the elderly increases the risk of dementia by one and a half times and vascular dementia by 2.6 times. A combination of diabetes mellitus and systolic hypertension or heart disease greatly increases the risk of vascular dementia by 11.3 times. Thus effective treatment and management of cardiovascular disease and diabetes helps reduce the risk of dementia.

Source: summary of medical news story as reported by Reuters Health

Diabetes increases eye problems

2009-10-30T10:46:00.000-07:00

Diabetes is a multisystem disease that has effects on the end organs of the body, which includes the eyes. Diabetic retinopathy, glaucoma and macular edema are some diabetic eye complications which are the greatest cause of blindness in America. Warning signs of eye problems are changes in vision, involving blurring, flashers, floaters and reduction in sight. Treatment with laser or surgery is only effective in early stages of the eye disorders. These eye diseases are suspected in diabetics necessitating yearly eye checks by an ophthalmologist.

Protect Yourself From Breast Cancer

2009-10-02T06:13:00.000-07:00

Protect Yourself From Breast Cancer

DID YOU KNOW:
The American Cancer Society has awarded approximately $388.4 million to breast cancer research since 1971.

ACS funded research that led to the development of lifesaving breast cancer drugs such as tamoxifen and Herceptin, as well as discovery of the breast cancer gene.

In October 2004, the Society began a collaboration with the National Institute of Environmental Health Sciences (NIEHS) on the Sister Study, a nationwide study to learn about the environmental and genetic causes of breast cancer.

If you see pink everywhere you turn this month, here's why: October is National Breast Cancer Awareness Month, a time when survivors, advocates, and health organizations strive to raise awareness of the progress we're making together in fighting this disease – and the things women can do to protect themselves.

Since 1990, more and more women have been surviving breast cancer, largely because of early detection through mammography and improvements in treatment. However, breast cancer is still the second leading cause of cancer death in women, exceeded only by lung cancer.

Mammograms can find breast cancers earlier, when they are easier to treat and the chances of survival are higher. That's why the American Cancer Society recommends yearly mammograms and breast exams for women 40 and older. If you're putting off getting your mammogram because you're scared or nervous, watch some real women talk about their experience. You'll see this life-saving test is nothing to be afraid of.

And don’t forget that in addition to getting a yearly mammogram, there are steps women can take to reduce their risk of breast cancer:

Eat a healthy diet to help control weight, since being overweight or obese may raise breast cancer risk.
Get regular physical activity. The American Cancer Society recommends 30 minutes a day, 5 or more days a week. Forty-five to 60 minutes a day is even better for reducing breast cancer risk.
Limit the amount of alcohol you drink to no more than 1 drink per day. Alcohol is clearly linked to an increased risk of developing breast cancer.
And perhaps most important, be sure to talk to your doctor if you notice any changes in your breasts or have any other concerns. That conversation could save your life.

NIH NEWS

2009-10-02T06:09:00.000-07:00

For many people, laser eye surgery can correct their vision so they no longer need glasses or contact lenses. Laser eye surgery reshapes the cornea, the clear front part of the eye. This changes its focusing power.
There are different types of laser eye surgery. LASIK - laser-assisted in situ keratomileusis – is one of the most common. Many patients who have LASIK end up with 20/20 vision. But, like all medical procedures, it has both risks and benefits. Only your eye doctor can tell if you are a goodFrozen Assets: NIAID Researchers Turn to Unique Resource for Clues to Norovirus Evolution
A search through decades-old frozen infant stool samples has yielded rich dividends for scientists from the National Institute of Allergy and Infectious Diseases (NIAID), part of the National Institutes of Health. The team customized a laboratory technique to screen thousands of samples for norovirus, a major cause of acute gastroenteritis outbreaks in people of all ages. What they discovered about the rate of evolution of a specific group of noroviruses could help researchers develop specific antiviral drugs and, potentially, a vaccine against a disease that is very unpleasant and sometimes deadly.

The research, led by Kim Y. Green, Ph.D., and Karin Bok, Ph.D., of NIAID's Laboratory of Infectious Diseases, will appear in a future issue of the Journal of Virology, and is now available online. NIAID scientist Albert Z. Kapikian, M.D., is a co-author on the paper. In 1972, Dr. Kapikian and colleagues identified and characterized the virus, now known as norovirus, responsible for an outbreak of acute gastroenteritis in Norwalk, Ohio, in 1968.

"Thanks to the foresight of Dr. Kapikian and others at NIAID and the Children's National Medical Center who established and have maintained these clinical samples since 1974, our researchers have a unique resource that represents one of the oldest sets of norovirus samples in the world," says NIAID Director Anthony S. Fauci, M.D. "This is the first study to look at samples that date back almost to the first recorded cases of norovirus outbreaks, more than 40 years ago."

Highly contagious, noroviruses are responsible for an abrupt onset intestinal ailment also called winter vomiting disease or cruise-ship disease. The Centers for Disease Control and Prevention (CDC) estimates that 23 million cases of acute gastroenteritis each year are due to norovirus infection and that noroviruses are the cause of more than half of all food borne gastroenteritis outbreaks. In elderly people, infants and people with compromised immune system function, dehydration resulting from vomiting and diarrhea following norovirus infection can be life-threatening. In developing countries, according to a 2008 estimate by CDC researchers, up to 200,000 children under 5 die of norovirus infection each year. There is no vaccine against norovirus and no specific antiviral drugs to treat infections.

A key question for norovirus researchers is determining when a dominant variant, called genotype II.4 (or GII.4), first emerged, notes Dr. Green. " This genotype has been associated with the majority of global outbreaks of acute norovirus gastroenteritis since the mid-1990s," says Dr. Green. " The GII.4 genotype was first described around 1987, but no one knew for sure whether that genotype emerged then or if it existed earlier."

To answer the question, Dr. Bok customized a new technique — real-time reverse transcriptase-polymerase chain reaction (RT-PCR)—and applied it to stool samples originally collected from infants and young children hospitalized at the Children's National Medical Center in Washington, D.C., between 1974 and 1991. Samples were taken from infants and children with gastroenteritis and from others (controls) who did not have gastroenteritis. Essentially, Dr. Bok crafted genetic hooks capable of fishing out matching genetic sequences of any norovirus present in the samples. Fifty out of 5,424 samples tested contained norovirus. The most commonly seen genotype was GII.3 (48 percent), but the second most common genotype was GII.4 (16 percent). Some GII.4-containing specimens dated back to 1974, allowing the researchers to conclude that this now-dominant genotype had been circulating for years before its more recent identification as the cause of severe global outbreaks of norovirus disease.

Next, using a strategy developed by NIAID scientist Stanislav Sosnovtsev, Ph.D., the researchers determined the complete genetic sequences of five older GII.4 viruses and compared those sequences to gene sequences of contemporary GII.4 noroviruses. The comparison allowed the investigators to determine how much the archival viruses differed from the most recent representatives of the same genotype and, thus, to calculate how quickly the GII.4 genotype is evolving.

Currently, there are no antiviral drugs specifically targeted to noroviruses, but the new knowledge about which segments of the norovirus genome change the least could aid in the development of novel drugs that could be targeted at those more genetically static portions of the virus, say the researchers. Noroviruses, like influenza viruses, mutate readily and evolve rapidly, explains Dr. Green. If vaccines against noroviruses become possible in the future, researchers would need to take into account shifts in the virus's genetic make-up and reformulate the vaccines to match the virus, she adds. However, unlike influenza viruses, noroviruses cannot be grown in the lab, raising an additional hurdle to vaccine development.

" By examining the history of norovirus evolution contained within these archival samples, we can see how the virus has changed during this time, and we also can better predict how the virus is likely to change in the future," says Dr. Bok. If scientists one day crack the problem of growing norovirus in the lab, information about the rate of evolution will be invaluable to developing vaccines, adds Dr. Green.

"This research is the first to reveal the speed at which the molecular clock of norovirus runs," says Dr. Green. Dr. Green and her colleagues are now looking at stool samples from the 1960s in Dr. Kapikian’s collection. If norovirus can be detected in those samples, knowledge about the ancestry and rate of evolution of this virus will be further expanded.

Additional information about noroviruses is available from NIAID at http://www3.niaid.nih.gov/topics/norovirus/ and from the CDC at http://www.cdc.gov/ncidod/dvrd/revb/gastro/norovirus-factsheet.htm

NIAID conducts and supports research — at NIH, throughout the United States, and worldwide—to study the causes of infectious and immune-mediated diseases, and to develop better means of preventing, diagnosing and — treating these illnesses. News releases, fact sheets and other NIAID-related materials are available on the NIAID Web site at http://www.niaid.nih.gov.

The National Institutes of Health (NIH) — The Nation's Medical Research Agency — includes 27 Institutes and Centers and is a component of the U.S. Department of Health and Human Services. It is the primary federal agency for conducting and supporting basic, clinical and translational medical research, and it investigates the causes, treatments, and cures for both common and rare diseases. For more information about NIH and its candidate for laser eye surgery.

BEST EYE SPECIALIST DR AZHAR QAZI FROM SIALKOT

2009-09-06T17:41:00.000-07:00

HE IS ONE OF THE BEST EYE SPECIALIST IN PAKISTAN HE IS BASICALLY FROM SARGODHA.....!!HE LOVES HER MOTHER MORE THEN ANYONE...........

all laser services

2009-07-09T23:40:00.000-07:00

Laser Service, Professionalism Defined

Laser Service Inc. has a unique approach to service - simply being true to
the word "service" Our committment to our customers is made clear
by our range and focus of services and product offerings. Partnerships
and alliances with other industry leaders has allowed us to provide
a wide range of services for our customers.

Preventive maintenance plans can be setup for virtually any
number of printers and the results are exponential to the number
of printers covered. Preventive maintenance relies on the fact
that a printer that has its major assemblies cleaned on a regular
basis can be much more reliable than an unprotected printer with
the same workload.

Laser Printer Ink Cartridges

2009-07-08T19:35:00.000-07:00

Need new ink cartridges for your Laser printer? Then your at the right site that will inform you all about laser printers and laser printer ink toner cartridges.

Laser Printer Ink Cartridges
WARNING LOW INK LEVELS!

Need new ink cartridges for your Laser printer? Then your at the right site that will inform you all about laser printers and laser printer ink toner cartridges.

Laser Printer

A Laser printer is a common type of computer printer that was invented by Xeron in 1969, and by 1972 it was a fully functional networked printer. It has been around a long time giving itself plenty of advancements in technology. Laser printers rapidly produce high quality text and graphics onto a piece of computer paper. Today's common laser printers have a xerographic printing process that produces the image by direct scanning of a laser beam across the printer photoreceptor. There are many advantages of laser printer over analog photocopier or ink jet printers.

•Speed
•Precision
•Economy
A laser printer can move very quickly and can write with much more speed than an ink jet printer, and with it's laser beam having an unvarying diameter it can draw more precisely without spilling excess ink. While they are slightly more expensive than your average ink jet printer they are cheaper to maintain.
How they work
A laser beam projects an image onto an electrically charged rotating drum. Photoconductivity removes charges from certain areas that are exposed to light, then dry ink particles are electrostatically attracted by the drums charged areas. The drum then prints the image onto a piece of paper by using direct heat and contact which fuses the ink to the paper.

After printing numerous amounts of paper the dry ink toners begin to run low, and eventually run out of ink. Without and ink in the ink cartridges the printer will not be able to print.

Time to change those empty ink cartridges
With today's new technology you can know you laser printers ink cartridges are low before they run out of ink. All companies have built in programs that allow you to know where your printer ink levels are at all times. Each time you print your printer will automatically put up a display on your computer showing your current ink levels. This tool is great for you so you don't run out of ink the night before you have to print a document without even knowing your printer was low.

•There are two ways to get full ink cartridges in your laser printer. You can ether buy a new ink cartridge or refill your current ink carridge. Laser Printer consist of a dry ink toner unlike ink jet printers that use wet ink, but the refilling consists of the same process.

-Refilling ink cartriges is the cheapest most economical way to restoring your printers ink levels. There are many places that offer ink cartridge refills such as Walgreen's, and existing printer maintenance shops. You can even refill you printers ink cartridges yourself with the proper kit. Research the Internet to find local stores that offer printer ink cartridge refills, or DIY refill kits. However not all printer are able to have printer ink cartridges refills.

-Buying a new ink cartridge is the most expensive way to replace your low ink levels in your printer. When buying ink cartridges straight from your printer manufacturer it can be very expensive compared to buying compatible after market ink cartridges. People who buy compatible non name brand cartridges often save anywhere from 50 to 70 percent. Some stores offer discounts off of new ink cartridges and toner when you recycle your old cartridges in to them.

CHEAPEST RAY-BAN GLASSES IN THE WORLD

2009-07-08T19:23:00.000-07:00

CARRERA 2009 SUN GLASSES

2009-07-08T17:25:00.000-07:00

Brand: Carrera
Model: OLYMPIA 2
Price: Euro 112.23
$ 147.02 :: £ 98.762

Brand: Carrera
Model: OLYMPIA 1
Price: Euro 112.23
$ 147.02 :: £ 98.762

Brand: Carrera
Model: CHAMPION
Price: Euro 91.35
$ 119.66 :: £ 80.388

Brand: Carrera
Model: TRUMP/V
Price: Euro 147.9
$ 193.74 :: £ 130.15

LATEST EYE WEAR

2009-07-08T17:23:00.001-07:00

When you wear a pair of Tom Ford Sunglasses you are making a serious fashion statement.
When you own a pair of new Tom Ford sunglasses, you own a key to unlock the world of high fashion. People understand what Tom Ford sunglasses mean; they know that someone who wears Tom Ford Eyewear is someone who has a high sense of fashion and a high standard of quality.
The cutting edge of Tom Ford design is offered to you on Sunglassitaly.com because we only stock the Latest collection of Tom Ford Sunglasses and Eyewear.
Sunglassitaly.com recognizes that Tom Ford sunglasses are a way to show off your own unique sense of style and we pride ourselves on offering the largest collection of new Tom Ford sunglasses and eyewear to our customers.

Bulgari has the best to offer

Bvlgari sunglasses are like nothing you have ever seen before. When you look at the authentic Bvlgari sunglasses offered to you here, at Sunglassesitaly.com, you will be amazed by the luxury that is delicately presented in each pair. They are like nothing you have seen before. If you want to be original in your choice of eyewear and want to be alone in your exclusivity of elegant design, then Bulgari sunglasses is the right decision for you.

Bulgari eyeglasses from the distinctive Bulgari manufacturer. Bulgari specialise in luxury jewellery that defines both chic style and elegance. Bulgari have now added eyeglasses to their collection and Sunglassesitaly.com are proud to present them exclusively to you online.

Buy Gucci Sunglasses to elevate your style

Gucci Sunglasses are the ultimate in style and craftsmanship, when you wear a pair of Gucci sunglasses you are making a serious fashion statement.
When you own a pair of new Gucci sunglasses, you own a key to unlock the world of high fashion. People understand what Gucci sunglasses mean; they know that someone who wears Gucci sunglasses is someone who has a high sense of fashion and a high standard of quality.
Sunglassitaly.com recognizes that Gucci Eyewears are a way to show off your own unique sense of style and we pride ourselves on offering the largest collection of new Gucci sunglasses and new Gucci Eyeglasses to our customers.

Be the Best with Chanel Eyewear

Do you feel strongly about fashion eyewear? So do we. Here at Sunglassesitaly.com we feel that Chanel eyeglasses are the ultimate in luxury fashion eyewear and we know that after browsing through out latest Chanel collection, you will be sure to agree.

Chanel eyeglasses combine the elegance of style with their simple and sublime designs. The optical frame offered by Chanel eyewear is like no other. The feel of extravagance is delectably accessible in every pair of fashionable Chanel eyewear that we offer. One look at our latest authentic Chanel collection will persuade you of their complete magnificence in that elusive combination of style and luxury.

Chanel Sunglasses beautify your life

Sunglassitaly.com understands how important Chanel sunglasses are. That is why we are one of the only online stores to hold the full, authentic online Chanel sunglasses collection.
Sunglassitaly.com has seventy-five different types of online Chanel sunglasses for you to choose from, direct from the manufacturer. No other online Chanel sunglasses site can offer this much selection. No other retailer can give you the full sunglasses Chanel collection. See how our sunglasses by Chanel can bring beauty and glamour into your life today.
The Chanel logo is instantly recognized world wide, and when you are wearing Chanel sunglasses you are speaking everyone’s language.
We only stock the latest collections of Chanel sunglasses, so when you shop with sunglassitaly.com you can be assured that you are wearing the hottest eyewear available. Our online Chanel sunglasses are offered to you at unbeatable prices because we believe that everyone should own a little bit of Chanel glamour.
Chanel sunglasses provide an elegance that makes any woman wearing them feel full of femininity and grace, and the latest collection is inspired.

Laser eye surgery in Thailand

2009-07-08T11:48:00.000-07:00

If you decided to go for LASIK and kiss your eye glasses or contact lenses good-bye, Bangkok is one of the best places in the world for LASIK! And at unbelievably low prices, if you compare with Europe, America, Japan, Hong Kong or Singapore.

Better still, your LASIK surgeon most likely was trained in Europe, America, Japan, Hong Kong or Singapore. You choose. And once you made up your mind, you can usually have an appointment for the next day to have your pre-exam and... in some cases, if the pre-exam results are OK and you feel comfortable about the facility, the operation can be performed on the same or the following day.

My positive experience with my own LASIK operation in Bangkok, Thailand was one of the triggers that caused me to start the MediThai website. Not only did I think it was a great experinece, I also started to recommend it to members of my family in Europe and to friends all over the world.

Getting started
The navigation bar on the left side of this window is self explanatory. Click yourself through the pages. It starts at the top with general considerations and then gets more specific further down. Try also a search on the customized MediThai search engine for Thailand specific search results. Please don't forget to leave us some feedback regarding your own experience. We all can benefit from it.

Work in progress
We hope you can already find something useful on our site. See it as a beginning. With your feedback we should be able to improve the content over time and make the portal a more valuable source of information for everybody who wants to know more about LASIK in Bangkok and other parts of Thailand.

LASIK IN THAILAND

2009-07-08T11:38:00.000-07:00

Over the last few years Thailand has become a hub for medical tourists from all around Asia and the rest of the world. Medical tourism has existed for centuries – people from less developed countries traveled to more advanced places to see a dentist, for cosmetic or plastic surgery and for general health checks and surgery. Think of all the rich and famous who still travel to the US for their medical needs. While places like the US are still attractive for the mega rich, general traffic patterns have changed. Countries like Thailand have caught up with the development of medical science in the west and have at the same time been able to maintain their higher service levels and their considerably lower prices.

The Thai medical education system is based on the US model. King Bhumipol’s father, Prince Mahidol, had earned a medical degree from Harvard University and made it his life’s work to modernize the healthcare system in Thailand. During his time he convinced the Rockefeller Foundation to fund an American medical education for a group of Thai men and women. These men and women became the nucleus of the Thai healthcare education system.

Key factors contributing to Thailand’s development into a global hub for medical tourism:

Many foreigners have made Thailand their home and began to spread the word about Thai medical services
Early success enabled investment in world-class medical equipment and technology
International accreditation of Thai hospitals
High numbers of internationally trained, English-speaking Thai doctors
Exorbitant healthcare costs in western countries
Long waiting lists for surgery in countries with government regulated healthcare
Low service levels in countries with nationalized health care
Plane tickets to Thailand have become more affordable
Thailand’s reputation as the Land of Smiles: friendly people, superb beaches and fantastic food.

best teachers in the world

2009-07-08T11:33:00.001-07:00

The Best Teacher in the World
e-mail to a friend | print this | link to this
Contributed by: Annie Johnson on 4/26/2007

Hello,
My name is Annie Johnson, from Denver, Colorado. I would like to nominate Stephanie Prosenjak for the 2007 Dance Teacher Awards. When I saw the add for this nominationI immediately thought of Stephanie. She is an amazing woman, dance teacher, and mother figure towards me, who has made me the 17 year old I am today. Ever since my first dance class at age four, Stephanie has been ainspiration to me. She has dedicated her entire life to her passion for dancing and dance education. She is the most driven person I know, and holds an irreplaceable place in my heart. Sheworksextremely hard day to day sharing her love for the art of dance. She began her own studio, Cherry Creek Dance, at a young age and has successfully made it a thriving studio of dance education and performance. A day never goes by where Stephanie isn't hard at work, encouraging students to open up and express their inner beauty through dance. Stephanie continuously enforces the importance of "self" in dance class, stressing the need for self dedication, commitment, and love for dance in order to succeed.Stephanie always encourages students, including myself, to usethe talent of dance at hand to give back to the community. We have performed at various occasions, such as the Juvenal DiabetesResearch Foundation, that have everlasting memories.Stephanie has opened up my eyes to the world of dance by giving us incredible opportunities of sharing our love for dance and performance across the world. Without her, I wouldnever have found my true passion for dance. Everyday I look forward to going to dance. Seeing Stephaniedoing what she loves to do always puts a smile on my face. Her life has been committed to educating people of all ages on the beauty of the art of dancing and has taught me how to be an extremely responsible and organized person. I thank her foralways bringing outmy very best from being achild to a young adult, showing me my potential in life. Anyone who has lived in Denverfor a while knows about Stephanie and Cherry Creek Dance, makingher a well known woman in the realistically small world to dance. Over the past 13 years of knowing Stephanie, she has made me feel like aunique and special person, in return making her like a mother to me. I love Stephanie very much and hope you can see the twinkle in her eyes that makes her the best dance teacher EVER! Thanks so much for your time.Hope to hear from you soon.
Annie Johnson
Age 17
Denver, Colorado

best teachers in the world

2009-07-08T11:33:00.000-07:00

Excimer Laser System

2009-07-08T07:59:00.000-07:00

We are proud to announce launch of New Vision Lasik Center equipped with worlds most advanced ,fastest and safest Allgretto Wave Eye Q 400 Hz Lasik Laser Vision correction machine.

Allegreto Wave Eye - Q 400Hz

LASIK (safe, Effective, permanent)
Lasik is done by Allegretto Wave eye Q (400 HZ) & Moria evolution 3e with epilasik, microkeratome.

Allegretto Wave Eye Q is FDA approved to treat + 6.0 D to -12.0 D spherical errors & +/- 6.0 D of cylindrical errors.
Speed - Truly efficient 400HZ fast speed repetition minimizes effect of dehydration and external environmental influences on cornea.
E.g. - 6.0 D myopia takes merely 15 seconds to be treated.
Ablation Profile – It is first laser to use wavefront optimized profiles.
This profile maintains corneal asphericity reducing problems with night vision.

LASER EYE SURGERY(Diabetic Retinopathy)

2009-07-08T07:57:00.000-07:00

What is Diabetic Retinopathy?
India stands to become largest diabetic population by 2010.Population of diabetic patients in India is 34 million acording to various sources.

A person with diabetes is at risk for developing diabetic retinopathy among other ophthalmic disorders. Diabetic retinopathy is the leading cause of blindness in young and middle-aged adults today. The longer a person has diabetes, the greater their chance of developing diabetic retinopathy. There are two types of diabetic retinopathy:

Non-Proliferative Diabetic Retinopathy (NPDR)
Proliferative Diabetic Retinopathy (PDR)

NPDR, also known as background retinopathy, is an early stage of diabetic retinopathy and occurs when the tiny blood vessels of the retina are damaged and begin to bleed or leak fluid into the retina resulting in swelling (diabetic macular edema) and the formation of deposits known as exudates. Many people with diabetes develop mild NPDR often without any visual symptoms.

Normal Retina Non-Proliferative Diabetic Retinopathy

PDR carries the greatest risk of loss of vision and typically develops in eyes with advanced NPDR. PDR occurs when small blood vessels on the retina or optic nerve become blocked consequently starving the retina of necessary nutrients. In response, the retina grows more blood vessels (neovascularization). Unfortunately these new vessels are abnormal and cannot replenish the retina with normal blood flow.

PDR may lead to any one of the following
Vitreous hemorrhage - proliferating retinal blood vessels grow into the vitreous cavity and break down. Both the hemorrhaging and resultant scar tissue may interfere with vision.
Traditional retinal detachment - scar tissue in the vitreous and on the retina cause the retina to detach.
Tractional and rhegmatogenous retinal detachment - scar tissue creates a hole or tear in the retina causing it to detach.
Neovascular glaucoma - abnormal blood vessel growth on the iris blocks the flow of fluid out of the eye causing the pressure to increase and damaging the optic nerve.

What are the symptoms of diabetic retinopathy?
Generally, people with mild NPDR do not have any visual loss. A dilated eye exam is the only way to detect changes inside the eye before loss of vision begins. People with diabetes should have an eye examination at least once a year. More frequent exams may be necessary after diabetic retinopathy is diagnosed.

People with PDR experience a broader range of symptoms. They may
see dark floaters
experience loss of central or peripheral vision
experience visual distortions or blurriness
experience temporary or permanent vision loss

How is diabetic retinopathy diagnosed ?
Diabetic retinopathy is diagnosed by dilating the pupil and looking inside the eye with an ophthalmoscope. If an ophthalmologist discovers diabetic retinopathy, he or she may wish to order color photographs of the retina through a test called fluorescein angiography. During this test, a dye is injected into the arm and quickly travels throughout the blood system. Once the dye reaches the blood vessels of the retina, a photograph is taken of the eye. The dye allows the ophthalmologist to detect damaged blood vessels that are leaking dye.

Can diabetic retinopathy be prevented ?
The most effective overall strategy for diabetic retinopathy is to prevent it as much as possible. Strict control of blood sugar levels will significantly reduce the long-term loss of vision from retinopathy. With improved diagnosis and treatment, only a small percentage of people with retinopathy develop serious vision problems.
What are the current treatment options for a person with diabetic retinopathy ?
Because the earliest stages of diabetic retinopathy include inflammation, intraocular corticosteroids have been utilized with some success in selected patients. This form of treatment includes the use of a long-acting corticosteroid (triamcinolone acetonide) injected into the vitreous cavity by way of a very tiny needle under topical (drops) anesthesia. This treatment may reduce retinal swelling and improve visual acuity in patients with diabetic macular edema. However, visual recovery may be limited and the effect may last only 3 to 6 months after the treatment. Other newer modalities like Anti vascular endothelial growth factor drugs( Lucentis,Macugen and Avastin )have been proved to be quite successful in reducing macular edema and new vessels temporarily.However they do not work well all alone unless combined with adequate photocoagulation.

What does Shree Ramkrishna Netralaya offer patients with diabetic retinopathy?
Diabetic Eye Unit established at SRN provides constant care for diabetic patients.It involves routine screening of diabetics to detect retinopathy.If detected early patients can be managed medically by FFA and laser treatment,thereby preventing further decrease in vision.

We have found very encouraging results with use of Anti VEGF drugs like Avastin and Lucentis in cases of macular oedema and PDR cases .

Patients presenting at a later stage with decreased vision due to vitreous hemorrhage and tractional retinal detachement require vitrectomy We have experienced VR surgeon to perform vitreoretinal sugeries
Procedures at Shree Ramkrishna Netralaya
Fundus fluorescein angiography (FFA) with Fundus Camera (Carl Zeiss Meditech,Germany)
PRP( Pan retinal photocoagulation) argon Green laser (Iris Medical,USA)
Grid laser
Cryopexy
A R M D Management
PDT (Photo Dynamic Therapy)
Anti VEGF Injections (Lucentis and Macugen
Scleral buckling
Vitrectomies
Trauma Care

VISION HEALTH

2009-07-07T17:29:00.000-07:00

Vision Health
Whether you're interested in finding out more about what constitutes low vision, what macular degeneration is, or whether vision rehabilitation is something you should consider, Lighthouse International offers information and resources that can help. Learn more about our services and some of the most common eye disorders.

Macular Degeneration

As the most common cause of vision loss among people over the age of 60, macular degeneration impacts millions of older adults every year. The disease affects central vision and can sometimes make it difficult to read, drive or perform other activities requiring fine, detailed vision. Here, you'll find all you need to know about the disease, symptoms, diagnosis and treatments.

Read more about Macular Degeneration and other view simulations of other vision disorders.

Low Vision Defined

Vision loss that cannot be corrected by ordinary glasses, contact lenses, medication or surgery is called "low vision." Signs of low vision include:

•Difficulty recognizing a familiar face
•Difficulty reading - print appears broken or distorted
•Difficulty seeing objects and potential obstacles such as steps, curbs, walls and furniture
But people with low vision retain some usable vision. Ophthalmologists and optometrists specializing in low vision care can evaluate patients and prescribe optical devices to maximize remaining vision.

What Do You Do When You Meet Someone Who Can't See?

It's only natural to feel awkward when dealing with new situations. And, meeting someone with a vision impairment or any disability often causes feelings of discomfort and uncertainty. A little knowledge can go a long way in making you feel more at ease and better able to provide help if it's needed.

EYE DISEASES

2009-07-07T17:17:00.000-07:00

When you think about it, the very act of actually seeing the world around us is an astonishing thing. It relies on the interaction between the brain and the eyeball, two extraordinarily complex organs, so it's hardly surprising that there are so many ways in which we can suffer sight loss or reduction.
Cataract
Cataract is the clouding of the eye's lens - the part of the eye responsible for focusing light and producing clear, sharp images.

Childhood blindness
Of the 45 million people worldwide who are blind, around 1.4 million are children under 16. The vast majority of childhood blindness happens before the age of five - a period when 75 per cent of learning is through sight.

Diabetic retinopathy
Diabetic retinopathy is the sixth most common cause of blindness globally, affecting 1.8 million people. It is caused by damage to the small blood vessels in the retina at the back of the eye.
Glaucoma
Glaucoma is the third biggest cause of blindness worldwide. It affects around 60 million people, of whom about 4.5 million have become blind. It is common in both developed and developing countries
Low vision
Low vision is when, even after medical treatment, people have difficulty distinguishing objects and/or distances. People with low vision can be helped by changes made to their environment, such as painting the edges of stairs white so they can be seen more easily, or specially made devices.
River blindness
River blindness is caused by a worm that breeds in fast-flowing rivers. It is a major cause of blindness in west and central Africa. Sightsavers is combating it with the drug Mectizan....

Trachoma
Trachoma is one of the most common causes of blindness in the developing world. It is linked to extreme poverty and poor sanitation.

TOP 10 MEDICAL SCHOOLS

2009-07-07T17:11:00.000-07:00

1. Harvard University
2. Johns Hopkins University
3. University of Pennsylvania
4. Washington University in St. Louis
5. University of California San Francisco
6. University of Washington
7. Stanford University
8. Duke University
9. Yale University
10. Baylor College of Medicine (TX)
Columbia University College of Physicians and Surgeons (NY)

Top 10 medical schools (primary care)

1. University of Washington
2. University of North Carolina - Chapel Hill
3. University of Colorad-Denver and Health Sciences Center
4. Oregon Health and Science University
5. Mich. State U. Coll. of Osteopathic Medicine
6. East Carolina University (Brody, NC)
7. University of Vermont
8. University of California - San Francisco
9. University of Wisconsin Madison
10. University of Nebraska College of Medicine.

SPIDER VEINS

2009-07-07T17:04:00.000-07:00

Laser treatment of spider veins

During laser treatment, a laser is applied to the skin over your spider veins. Laser energy causes your spider veins to coagulate and shrink. Laser therapy is most effective for small and medium size spider veins. Large spider veins respond poorly and are best treated with sclerotherapy. You are likely to experience mild discomfort similar to having a small rubber band snapping against skin. Treatments usually do not require sedatives, pain medications, or injections of local anesthetic. Immediately following treatment, spider veins will be darker and more visible. Over two to six weeks, your spider veins usually fade. After each treatment, you will see a 70% to 80% improvement in the appearance of face spider veins and 30-40% improvement in leg spider veins. An average of three treatments will be required at three-month
intervals to produce desired results. Combination therapy can be considered and beneficial if you have small, medium and large spider veins. You may wish to start with sclerotherapy, because sometimes all veins will be improved after injecting the larger ones. This may reduce the number of veins that need to be treated by laser and minimize your overall cost.

laser treatment spider veins

2009-07-07T17:01:00.000-07:00

Spider Veins
Spider Veins vs. Varicose Veins
Spider veins, also called telangiectasias, are tiny visible vessels just underneath the skin. They develop most commonly on the face and legs. Varicose veins are distended veins beneath the skin. They may appear as bluish bumps and often cause discomfort. Those with unsightly varicose veins and aching pain often choose to have surgery to remove their varicose veins. Varicose veins are veins that are no longer functional, and their presence is not missed by the body. Ask your general surgeon about varicose vein treatment. If you have both varicose and spider veins, your varicose veins must be
treated first. Treating spider veins first is generally futile because, in the presence of varicose veins, they are bound to return soon.
Treatment Choices for Spider Veins of the Legs
The two options for spider vein treatment are sclerotherapy and laser. They can be employed independently or in combination.

Sclerotherapy (spider vein injection)

Sclerotherapy involves injecting a liquid agent through a tiny needle directly into your spider veins, causing them to contract and collapse. This procedure is best suited for medium to large spider veins because it relies upon fitting a tiny needle into a tiny vein. The procedure is performed in the office by a plastic surgeon or nurse and is relatively painless. Depending on the number of spider veins, the procedure may require five minutes to one hour. Afterward, you will wear ace bandages or compression hose for three to ten days as recommended by your plastic surgeon. You may resume sedentary activities immediately but should avoid exercise, hot baths and alcohol for two to three days. You should anticipate 50% improvement in spider veins following each sclerotherapy session. Expect that two to six sclerotherapy sessions at one to two month intervals may be necessary to achieve your desired results. Understand that some
spider veins may never be successfully treated through sclerotherapy.

LIST OF HOSPITALS IN PAKISTAN(SINDH)

2009-07-07T17:00:00.000-07:00

Public institutions
Abbasi Shaheed Hospital, Karachi
Civil Hospital, Karachi
Civil Hospital, Sukkur
Civil Hospital - Burns Centre, Karachi, [6]
Habib Medical Centre, Karachi
Jinnah Postgraduate Medical Centre Karachi
Karachi Institute of Heart Diseases, Karachi
Kunri Christian Hospital, Umarkot
Lady Dufferin Hospital, Karachi
Leprosy Hospital, Karachi
Liaqat University of Health Sciences, Hyderabad
Lyari General Hospital, Karachi
National Institute of Cardiovascular Diseases, Karachi, [7]
National Institute of Child Health, Karachi
PNS Shifa, Karachi
Police Hospital, Karachi
Sindh Government Qatar Hospital, Karachi
Sindh Government Hospital New Karachi, Karachi
Sindh Institute of Skin Diseases, Karachi
Sindh Institute of Urology and Transplantation (SIUT), Karachi, [8]
Sindh Institute of Skin Diseases, Karachi
Sir Cowasjee Jehangir Institute of Psychiatry, Hyderabad
Sobhraj Maternity Home, Karachi
Spencer Eye Hospital, Karachi

[edit] Private institutions
ABM Hospital, Hyderabad
Aga Khan Hospital, Hyderabad
Aga Khan University Hospital, Karachi, [9]
Baqai Hospital,Karachi
Bismillah Taqee Institute of Health Sciences & Blood Diseases Centre, Karachi, [10]
Bantwa Memon Hospital, Karachi
Burhani Hospital, Karachi, [11]
Children Cancer Hospital, Karachi, [12]
CityCare Hospital, Hyderabad
Dar-ul-Sehat Hospital, (Liaquat Medical & Dental College) Karachi, [13]
Hamdard University Hospital, Karachi
Health Care Hospital, Karachi
Hilal-e-Ahmar Hospital, Hyderabad
Holy Family Hospital, Karachi
Al-Ibrahim Eye Hospital, Karachi [14]
Ibne-Sina (Avicenna) Hospital, Karachi
Imam Clinic and General Hospital, Karachi
Indus Hospital, Karachi, [15]
Isra University Hospital, Hyderabad
Ibrahim hospital Sargodha, Pakistan
Jinnah Medical College Hospital, Karachi
Karachi Adventist Hospital, Karachi, [16]
Kharadar General Hospital, Karachi
Kidney Centre Post Graduate Training Institute, Karachi, [17]
Kiran Hospital for Nuclear Medicine, Karachi
Kutiana Memon Hospital, Karachi
Layton Rahmatulla Benevolent Trust Eye Hospital, (LRBT) Karachi, [18]
Liaquat National Hospital, Karachi[19]
Majee Hospital, Hyderabad
Marie Adelaide Leprosy Centre (MALC), Karachi, [20]
Al-Mehrab Tibbi Imdad, Karachi
Masoomeen Hospital, Karachi
MidEast Hospital, Karachi
MediConnect, Karachi, [21]
Murshid Hospital and Health Care Center, Karachi
OMI Hospital, Karachi
Patel Hospital, Karachi
Saifee Hospital (Karachi), Karachi, [22]
Shilokh Mission Hospital, Jalapur Jattan, Gujrat
South City Hospital, Karachi
Tabba Heart Institute, Karachi, [23]

LIST OF HOSPITALS IN PAKISTAN(PRIVATE)

2009-07-07T16:58:00.000-07:00

Punjab.

Aadil Hospital, Lahore
Ali General Hospital, Multan
Ali Hospital, Lahore
Alle-Hussain Trust Hospital , Lahore
Al-Shifa Trust Eye Hospital, Rawalpindi
Ammar Medical Complex, Lahore
Aziz Bhatti Shaheed Hospital, Gujrat
Aziz Medical Complex, Sialkot, [2]
Al-Arsalan Clinic, Rawalpindi
Bahawal Victoria Hospital, Bahawalpur
Bait-Ul-Shifa Trust, Township, Lahore
Bakhtawar Amin Memorial Trust Hospital, Multan, [3]
Chattha Hospital Gujranwala
Doctor'S Hospital, Lahore
Doctor'S Hospital, Gujrat
Faisal Hospital,Multan
Family Hospital, Lahore
Fatima Medical Centre, Multan
Fatima Memorial, Lahore
Fauji Foundation Hospital, Lahore
Fauji Foundation Hospital, Rawalpindi
Fazal Hospital, Jhelum
Geo Hospital, Lahore
Gujrat Hospital, Gujrat
Gulberg Hospital, Lahore
Hameed Latif Hospital, Lahore
Healers Centre, Rawalpindi
Heart And City Scan Hospital, Lahore
Hearts International Hospital, Rawalpindi
Ihsan Mumtaz Hospital, Lahore
Idrees Hosipital,Sialkot
Iqraa Medical Complex, Lahore
Irshad Begum Chattha Hospital, Wazirabad
Ittefaq Hospital (Trust), Lahore
Jaanki Devi Hospital, Lahore
Khan Surgecal Center, Ali Pur Road, Muzaffar Garh
Life Medical Complex (Dr. Hafeez-Ur-Rehman), Gujrat
Malik Haider Hospital, Lady Dr. Salvi Malik, Gujrat
Malik Surgical Hospital, Lahore
Margalla Welfare Hospital, Rawalpindi
Maryam Memorial Hospital, Rawalpindi
Masood Children'S Clinic, Lahore
Masood Hospital,Gardentown, Lahore
Medicare Hospital, Multan
Mekki Hospital, Faisalabad
Memorial Christian Hospital, Paris Road, Sialkot
Mian Muhammad Trust Hospital, Faisalabad
Muazzam Shaheed Welfare Hospital, Jhelum
Mubarik Nursing Home, Rawalpindi
Mumtaz Bakhtawar Memorial Trust Hospital, Lahore
Nanotech Neurology Psychiatry and Joint Pain Center, Lahore
National Hospital, Faisalabad
National Hospital and Medical Centre, Lahore, [4]
Rasheed Hospital, Lahore
Razzaq Hospital, Lahore
Redo Hospital, Rawalpindi, [5]
Saahil Hospital, Faisalabad
Sadiq Hospital, Sargodha
Salamat Hospital, Gujranwala
Shalimar Hospital, Lahore
Sharif Meidcal City Hospital, Lahore
Shaukat Khanum Hospital, Lahore
Sialkot Medical Complex Sialkot
South Asia Institute for Human Sexuality, Rawalpindi
Sughra Hospital,Jhelum
Suhail Eye Hospital, Lahore
Surgimed Hospital, Zafar Ali Road, Lahore
Times Hospital, Lahore
Turab Hospital Complex, Township, Lahore
Umer Hospital, Wah
United Christian Hospital, Lahore
Valley Clinic, Rawalpindi
Wapda Hosital, Lahore
Zeenat Clinical Labs, Lahore, Lahore

LIST OF HOSPITALS IN PAKISTAN(PUNJAB)

2009-07-07T16:57:00.000-07:00

Public institutions (government owned and operated)
Allama Iqbal Memorial Hospital Sialkot
D.H.Q Hospital,Muzaffargarh
Data Darbar Hospital, Lahore
District Headquarters Hospital, Rawalpindi
Fatima Memorial Hospital, Shadman-Lahore
Gulaab Devi Hospital, Lahore
Holy Family Hospital, Rawalpindi
HOPE Rehabilitation Center for disabled, Lahore
DAWN REHABILITATION CENTER FOR DISABLED, Lahore
www.dawnrehabilitation.com
Jinnah Hospital, Lahore
Lady Aitchison Hospital, Lahore
Lady Willingdon Hospital, Lahore
Lahore General Hospital, Lahore
Mayo Hospital, Lahore
Nisthar Hospital, Multan
Psychiatric hospital, Lahore
Punjab Institute of Cardiology PIC, Lahore Pakistan
Railway Cairns Hospital, Lahore
Rawalpindi General Hospital, Rawalpindi
Sardar Begum Memorial Hospital Sialkot
Services Hospital, Lahore
Sheikh Zayed Hospital, Lahore
Sir Ganga Ram Hospital, Lahore
The Children's Hospital, Lahore

LIST OF HOSPITALS IN PAKISTAN(NWFP)

2009-07-07T16:56:00.000-07:00

Public institutions
Lady Reading Hospital[citation needed]
Khyber Teaching Hospital[citation needed]
Hayatabad Medical Complex[citation needed]
Ayub Medical Complex[citation needed]
Mardan Medical Complex[citation needed]
Saidu Group Hospitals, Swat[citation needed]
Mufti Mehmood Complex, Dera Ismail Khan[citation needed]
Tank Christian Hospital, Tank, Dera Ismail Khan[citation needed]
Dr. Murad Ali Ultrasound Clinic, Dabgari Garden, Peshawar

LIST OF HOSPITALS IN PAKISTAN(ISLAMABAD)

2009-07-07T16:54:00.002-07:00

Federal Government Services Hospital[citation needed]
Golra Welfare Hospital (Ghosia-Mahria Trust)[citation needed]
Pakistan Institute of Medical Sciences[2] (PIMS)
PAEC Hospital[citation needed]
Nescom Hospital[citation needed]
KRL Hospital[citation needed]
National Institute of Health[3]
CDA Hospital[citation needed]

Private institutions
Dr.Arshad Health Associates-Medical Facilities"Dr Arshad Health Associates". .
Integrated Health Services (IHS Pakistan)[citation needed]
IHS Children's Medical Center[citation needed]
Islamic International Medical Complex[citation needed]
Dar-ul-Shifa Hospital[citation needed]
Shifa International Hospital[4]
Ali Medical Centre,[citation needed], F-8 Markaz
Islamabad Specialist Clinic,[citation needed] F-8
Aslam Memorial Medicare Hospital[citation needed]
Islamabad Private Hospital[citation needed], Blue Area
Chee Chee Hospital[citation needed]
Elahi Medical Center,[citation needed] G-9/4

LIST OF HOSPITALS IN PAKISTAN(ISLAMABAD)

2009-07-07T16:54:00.001-07:00

LIST OF HOSPITALS IN PAKISTAN(ISLAMABAD)

2009-07-07T16:54:00.000-07:00

LIST OF HOSPITALS IN PAKISTAN(BALOCHISTAN)

2009-07-07T16:52:00.000-07:00

Mid East Hospital , Al Gilani Road, Quetta Tel:081-2821103-5
Akram Hospital, Quetta[citation needed]
Children's Hospital, Quetta[1]
Sardar Bahadur Khan TB Sanatorium, Quetta[citation needed]
Civil Hospital, Quetta[citation needed]
Sahib-uz-Zaman Hospital, Alamdar Road, Quetta[citation needed]
Asghar Hospital, Alamdar Road, Quetta[citation needed]
Ali Hospital, Toghi Road, Quetta[citation needed]
Al-Noor Hospital, Toghi Road, Quetta[citation needed]
Saleem Medical Complex, Double Road, Quetta[citation needed]
Railway Hospital, Quetta[citation needed]

LUNGS CANCER PREVENTION AND TREATMENT

2009-07-07T16:50:00.000-07:00

Prevention of lung cancer includes quitting smoking and avoiding exposure to potentially cancer-causing substances in the work environment.

Doctors use various treatments for both small cell and non–small cell lung cancer. Surgery, chemotherapy, and radiation therapy can be used individually or in combination. The precise combination of treatments depends on the type, location, and severity of the cancer, whether the cancer has spread, and the person's overall health. For example, in some people with advanced non–small cell lung cancer, treatment includes chemotherapy and radiation therapy before, after, or instead of surgical removal. Some people with non–small cell lung cancer survive significantly longer when treated with chemotherapy, radiation therapy, or some of the newer targeted therapies. Targeted therapies include drugs, such as biologic agents that specifically target lung tumors. Recent studies have identified proteins within cancer cells and the blood vessels that nourish the cancer cells. These proteins may be involved in regulating and promoting cancer growth and metastasis. Drugs have been designed to specifically affect the abnormal protein expression and potentially kill the cancer cells or inhibit their growth. For example, doctors may give epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors to people who have not responded to traditional chemotherapy regimens. Some people may receive vascular endothelial growth factor (VEGF) and VEGF receptor inhibitors in combination with standard chemotherapy regimens.

Laser therapy, in which a laser is used to remove or reduce the size of lung tumors, and photodynamic therapy, in which light is used to shrink tumors, are sometimes used. Radiofrequency ablation, in which an electrical current is used to destroy tumor cells, can sometimes be used in people who have small tumors or are unable to undergo surgery.

Surgery: Surgery is the treatment of choice for non–small cell lung cancer that has not spread beyond the lung (early-stage disease). In general, surgery is not used for early-stage small cell lung cancer, because this aggressive cancer requires chemotherapy and radiation therapy. Surgery may not be possible if the cancer has spread beyond the lungs, if the cancer is too close to the windpipe, or if the person has other serious conditions (such as severe heart or lung disease).

Before surgery, doctors do pulmonary function tests (see Symptoms and Diagnosis of Lung Disorders: Pulmonary Function Testing (PFT)) to determine whether the amount of lung remaining after surgery will be able to provide enough oxygen and breathing function. If the test results indicate that removing the cancerous part of the lung will result in inadequate lung function, surgery is not possible. The amount of lung to be removed is decided by the surgeon, with the amount varying from a small part of a lung segment to an entire lung.

Although non–small cell lung cancers can be removed surgically, removal does not always result in a cure. Supplemental (adjuvant) chemotherapy after surgery can help increase the survival rate.

Occasionally, cancer that begins elsewhere (for example, in the colon) and spreads to the lungs is removed from the lungs after being removed at the source. This procedure is recommended rarely, and tests must show that the cancer has not spread to any site outside of the lungs.

Radiation Therapy: Radiation therapy is used in both non-small cell and small cell lung cancers. It may be given to people who do not want to undergo surgery, who cannot undergo surgery because they have another condition (such as severe coronary artery disease), or whose cancer has spread to nearby structures, such as the lymph nodes. Although radiation therapy is used to treat the cancer, in some people, it may only partially shrink the cancer or slow its growth. Combining chemotherapy with radiation therapy improves survival in this group. People with limited or extensive-stage small cell lung cancer who have been responding well to chemotherapy may benefit from radiation therapy to the head to prevent spread of cancer to the brain. If the cancer has already spread to the brain, radiation therapy of the brain is commonly used to reduce symptoms such as headache, confusion, and seizures. Radiation therapy is also useful for controlling the complications of lung cancer, such as coughing up of blood, bone pain, superior vena cava syndrome, and spinal cord compression.

Chemotherapy: Chemotherapy is used in both non-small cell and small cell lung cancers. In small cell lung cancer, chemotherapy, sometimes coupled with radiation therapy, is the main treatment. This approach is preferred because small cell lung cancer is aggressive and has often spread to distant parts of the body by the time of diagnosis. Chemotherapy can prolong survival in people who have extensive-stage disease. Without treatment, the median survival is only 6 to 12 weeks.

In non–small cell lung cancer, chemotherapy also prolongs survival and treats symptoms. In people with non–small cell lung cancer that has spread to other parts of the body, the median survival increases to 9 months with treatment. Targeted therapies may also improve cancer patient survival.

Other Treatments: Other treatments are often needed for people who have lung cancer. Because many people who have lung cancer have a substantial decrease in lung function whether or not they undergo treatment, oxygen therapy (see Rehabilitation for Lung and Airway Disorders: Oxygen Therapy) and bronchodilators (drugs that widen the airways) may aid breathing. Many people with advanced lung cancer develop such extreme pain and difficulty in breathing that they require large doses of opioids in the weeks or months before their death. Fortunately, opioids can substantially relieve pain if adequate doses are used.

DIAGNOSIS

2009-07-07T16:38:00.000-07:00

Doctors explore the possibility of lung cancer when a person, especially a smoker, has a persistent or worsening cough or other lung symptoms (such as shortness of breath or coughed-up sputum tinged with blood). Usually, the first test is a chest x-ray, which can detect most lung tumors, although it may miss small ones. Sometimes a shadow detected on a chest x-ray done for other reasons (such as before surgery) provides doctors with the first clue, although such a shadow is not proof of cancer.

A computed tomography (CT) scan may be done next. CT scans can show characteristic patterns that help doctors make the diagnosis. They also can show small tumors that are not visible on chest x-rays and reveal whether the lymph nodes inside the chest are enlarged. Newer techniques, such as positron emission tomography (PET—see Symptoms and Diagnosis of Lung Disorders: Chest Imaging) and a certain type of CT called helical (spiral) CT, are improving the ability to detect small cancers. Oncologists frequently use PET-CT scanners, which combine the PET and CT technology in one machine, to evaluate patients with suspected cancer. Magnetic resonance imaging (MRI) can also be used if the CT or PET-CT scans do not give doctors sufficient information.

A microscopic examination of lung tissue from the area that may be cancerous is usually needed to confirm the diagnosis. In rare cases, a sample of coughed-up sputum can provide enough material for an examination (called sputum cytology). Almost always, doctors need to obtain a sample of tissue directly from the tumor. One common way to obtain the tissue sample is with bronchoscopy. The person's airway is directly observed and samples of the tumor can be obtained (see Symptoms and Diagnosis of Lung Disorders: Bronchoscopy). If the cancer is too far away from the major airways to be reached with a bronchoscope, doctors can usually obtain a specimen by inserting a needle through the skin while using CT for guidance. This procedure is called a needle biopsy (see Symptoms and Diagnosis of Lung Disorders: Needle Biopsy of the Pleura or Lung). Sometimes, a specimen can only be obtained by a surgical procedure called a thoracotomy (see Symptoms and Diagnosis of Lung Disorders: Thoracotomy). Doctors may also perform a mediastinoscopy, in which they take and examine samples of enlarged lymph nodes (a biopsy) from the center of the chest to determine if inflammation or cancer is responsible for the enlargement.

Once cancer has been identified under the microscope, doctors usually do tests to determine whether it has spread. A PET-CT scan and head imaging (brain CT or MRI) may be done to determine if lung cancer has spread, especially to the liver, adrenal glands, or brain. If a PET-CT is not available, CT scans of the chest, abdomen, and pelvis and a bone scan are done. A bone scan may show that cancer has spread to the bones. Because small cell lung cancer can spread to the bone marrow, doctors sometimes also do a bone marrow biopsy.

Cancers are categorized on how large the tumor is, whether it has spread to nearby lymph nodes, and whether it has spread to distant organs. The different categories are used to determine the stage of the cancer (see Symptoms and Diagnosis of Cancer: Diagnostic Tests and Staging). The stage of a cancer suggests the most appropriate treatment and enables doctors to estimate the person's prognosis.

Screening: Clinical trials are underway to determine the value of screening tests to detect lung cancer in people who do not have any symptoms. These trials use chest x-rays, CT scans, sputum examinations, or all these methods to try to detect cancer when it is at an early stage. However, screening so far has not been shown to improve lung cancer detection, and therefore screening is not recommended for people who have no risk factors and no symptoms. Tests can be expensive and cause people undue worry if they produce false-positive results that incorrectly imply that a cancer is present. The opposite is also true. A screening test can give a negative result when a cancer really does exist. For these reasons, it is important for doctors to try to accurately determine a person's risk for a particular cancer before screening tests are done (see Symptoms and Diagnosis of Cancer: Screening).

LUNG CANCER SYMPTOMS

2009-07-07T16:36:00.001-07:00

The symptoms of lung cancer depend on its type, its location, and the way it spreads. One of the more common symptoms is a persistent cough or, in people who have a chronic cough, a change in the character of the cough. Some people cough up blood or sputum streaked with blood (hemoptysis—see Symptoms and Diagnosis of Lung Disorders: Hemoptysis). Rarely, lung cancer grows into an underlying blood vessel and causes severe bleeding. Additional nonspecific symptoms of lung cancer include loss of appetite, weight loss, fatigue, chest pain, and weakness.

Complications: Lung cancer may cause wheezing by narrowing the airway. Blockage of an airway by a tumor may lead to the collapse of the part of the lung that the airway supplies, a condition called atelectasis (see Atelectasis). Other consequences of a blocked airway are shortness of breath and pneumonia, which may result in coughing, fever, and chest pain. If the tumor grows into the chest wall, it may produce persistent, unrelenting chest pain. Fluid containing cancerous cells can accumulate in the space between the lung and the chest wall (pleural effusions—see Pleural Disorders: Pleural Effusion). Large amounts of fluid can lead to shortness of breath. If the cancer spreads throughout the lungs, the levels of oxygen in the blood drop and become low, causing shortness of breath and eventually enlargement of the right side of the heart and possible heart failure (cor pulmonale—see Pulmonary Hypertension:Pulmonary Hypertension).

Lung cancer may grow into certain nerves in the neck, causing a droopy eyelid, small pupil, sunken eye, and reduced perspiration on one side of the face—together these symptoms are called Horner's syndrome (see Autonomic Nervous System Disorders: Horner's Syndrome). Cancers at the top of the lung may grow into the nerves that supply the arm, making the arm painful, numb, and weak. Tumors in this location are often called Pancoas't tumors. When the tumor grows into nerves in the center of the chest, the nerve to the voice box may become damaged, making the voice hoarse.

Lung cancer may grow into or near the esophagus, leading to difficulty swallowing or pain with swallowing.

Lung cancer may grow into the heart or in the midchest (mediastinal) region, causing abnormal heart rhythms, blockage of blood flow through the heart, or fluid in the sac surrounding the heart (pericardial sac).

The cancer may grow into or compress one of the large veins in the chest (the superior vena cava); this condition is called superior vena cava syndrome. Obstruction of the superior vena cava causes blood to back up in other veins of the upper body. The veins in the chest wall enlarge. The face, neck, and upper chest wall—including the breasts—can swell, causing pain. The condition can also produce shortness of breath, headache, distorted vision, dizziness, and drowsiness. These symptoms usually worsen when the person bends forward or lies down.

Lung cancer may also spread through the bloodstream to other parts of the body, most commonly the liver, brain, adrenal glands, spinal cord, or bones. The spread of lung cancer may occur early in the course of disease, especially with small cell lung cancer. Symptoms—such as headache, confusion, seizures, and bone pain—may develop before any lung problems become evident, making an early diagnosis more complicated.

Paraneoplastic syndromes (see What Are Paraneoplastic Syndromes?) consist of effects that are caused by cancer but occur far from the cancer itself, such as in nerves and muscles. These syndromes are not related to the size or location of the lung cancer and do not necessarily indicate that the cancer has spread outside the chest. These syndromes are caused by substances secreted by the cancer (such as hormones, cytokines, and various other proteins).

LUNG CANCER SYMPTOMS

2009-07-07T16:36:00.000-07:00

LUNGS CANCER TREATMENT

2009-07-07T16:31:00.000-07:00

Cigarette smoking is the most common cause of lung cancer.
One common presenting symptom is a persistent cough.
Chest x-rays can detect most lung cancers, but other additional imaging tests and biopsies are needed.
Surgery, chemotherapy, targeted agents, and radiation therapy may all be used to treat lung cancer.

Lung cancer is the leading cause of cancer death in both men and women. It occurs most commonly between the ages of 45 and 70, and has become more prevalent in women in the last few decades because more women are smoking cigarettes.

Cancer that originates from lung cells is called a primary lung cancer. Primary lung cancer can start in the airways that branch off the trachea to supply the lungs (the bronchi) or in the small air sacs of the lung (the alveoli). Cancer may also spread (metastasize) to the lung from other parts of the body (most commonly from the breasts, colon, prostate, kidneys, thyroid gland, stomach, cervix, rectum, testes, bone, or skin).

There are two main categories of lung cancer.

Non–small cell lung carcinoma: About 85 to 87% of lung cancers are in this category. This cancer grows more slowly than small cell lung carcinoma. Nevertheless, by the time about 40% of people are diagnosed, the cancer has spread to other parts of the body outside of the chest. The most common types of non–small cell lung carcinoma are squamous cell carcinoma, adenocarcinoma, and large cell carcinoma.
Small cell lung carcinoma: Also called oat cell carcinoma, this cancer accounts for about 13 to 15% of all lung cancers. It is very aggressive and spreads quickly. By the time that most people are diagnosed, the cancer has metastasized to other parts of the body.

Causes

Cigarette smoking is the leading cause of cancer, accounting for about 85% of all lung cancer cases. About 10% of all smokers (former or current) eventually develop lung cancer, and both the number of cigarettes smoked and number of years of smoking seem to correlate with the increased risk. In people who quit smoking, the risk of developing lung cancer decreases, but former smokers will still always have a higher risk of developing lung cancer than people who never smoked.

About 15% of people who develop lung cancer have never smoked. In these people, the reason why they develop lung cancer is unknown. Recent studies have found that some people with lung cancer who have never smoked have genetic mutations in the epidermal growth factor receptor (EGFR) gene. Although an environmental association has not clearly been established, it is believed that exposure to radon gas in the home may be a risk factor. Other possible risk factors include exposure to secondhand smoke and exposure to carcinogens such as asbestos, radiation, arsenic, chromates, nickel, chloromethyl ethers, mustard gas, or coke-oven emissions, encountered or breathed in at work. It is believed that the risk of contracting lung cancer is greater in people who are exposed to these substances and who also smoke cigarettes. Air pollution and cigar smoke also contain carcinogens, and exposure to these substances is associated with an increased risk of cancer. In rare incidences, lung cancers, especially adenocarcinoma and bronchioloalveolar cell carcinoma (a type of adenocarcinoma), develop in people whose lungs have been scarred by other lung disorders, such as tuberculosis.

EYE SPECIALIST

2009-07-02T17:06:00.000-07:00

We have one very simple goal: to provide quality, comprehensive, and personal eye care. We believe that quality eye care begins with doctors who care about you, not just for you.

At Eye Specialists, we offer state-of-the-art LASIK technology. For added patient comfort and convenience, we have our own in-house surgical center which houses our own VISX Star S4 excimer laser.

From routine eye exams for glasses or contact lenses to the latest technology in cataract or LASIK surgery, Eye Specialists provides the essentials for all your eye care and eye wear needs.

LASER EYE SURGERY (DIODE)

2009-07-02T16:31:00.000-07:00

Laser eye surgery is a safe and effective method of correcting visual problems, often removing the constant need for glasses. Our guide to laser eye surgery aims to cover all your questions, from what the procedure for laser eye surgery involves, the risks, the benefis and the different types of laser eye surgery. If you

There are 2 main methods of laser eye surgery used today:

1. LASIK Laser Eye Surgery
2. PRK Laser Eye Surgery

The major difference between the two surgeries is the way that the stroma, the middle layer of the cornea, is exposed before it is vaporized with the laser. In PRK, the top layer of the cornea, called the epithelium, is scraped away to expose the stromal layer underneath. In LASIK, a flap is cut in the stromal layer and the flap is folded back.

This guide provides an overview of laser eye surgery, including possible complications of treatment
Also called: Keratectomy, LASIK, LTK, PRK
For many people, laser eye surgery can correct their vision so they no longer need glasses or contact lenses. Laser eye surgery reshapes the cornea, the clear front part of the eye. This changes its focusing power.

There are different types of laser eye surgery. LASIK - laser-assisted in situ keratomileusis – is one of the most common. Many patients who have LASIK end up with 20/20 vision. But, like all medical procedures, it has both risks and benefits. Only your eye doctor can tell if you are a good candidate for laser eye surgery

HIGHPOWER LASER

2009-07-02T16:18:00.000-07:00

Sacher Lasertechnik offers state of the art tunable diode laser systems for industry and science. The combination of high power and performance really makes a difference. They are designed for spectroscopy laboratories as well as for industrial applications. Automated wavelength scans as well as all laser functions are accessable via GPIB, USB, RS232.

External Cavity Tapered Diode Laser in Littrow Configuration, up to 1000mW
Littrow Tiger Series: The TEC 300 External Cavity Tapered Diode Laser in Littrow configuration is designed for high output power up to 1000mW, narrow linewidth in the order of 1MHz and a moderate mode-hop free tuning range of up to 15GHz. Available wavelength are 765nm .. 1080nm.

External Cavity Tapered Diode Laser in Littman/Metcalf Configuration, up to 1000mW
Littman Tiger Series: The TEC 320 External Cavity Tapered Diode Laser in Littman/Metcalf configuration is designed for high output power up to 1000mW, narrow linewidth in the order of 500kHz and a moderate mode-hop free tuning range of up to 15GHz. Available wavelength are 765nm .. 1080nm.

External Cavity Broad Area Diode Laser System in Littrow Configuration, up to 1500mW
Cougar Series: The TEC 200 External Cavity Broad Area Diode Laser in Littrow configuration is designed for high output power up to 1500mW. Main application is optical pumping of gases and Raman spectroscopy. The linewidth is moderate in the order of 10GHz. Available wavelength are 630nm .. 1080nm.

Application Notes
Sacher Lasertechnik offers a large collection of application notes on external cavity diode lasers as Absorption Spectroscopy, Raman Spectroscopy, Metrology and Fluorescence Spectroscopy.

Technical Notes
Sacher Lasertechnik offers a large collection of technical notes which are downloadable as PDF Files.

Publications
Sacher Lasertechnik offers a large collection of Sacher publications or publications where Sacher equipment has been used. All documents are downloadable as PDF Files.

LASER DIODE CEO AND OTHERS

2009-07-02T16:13:00.000-07:00

These Laser Diode Arrays are offered on a variety of heat sink package types that are conductively cooled. The arrays should be mounted to a heat sink with a recommended base plate temperature of 25° C. In addition to the types of packages listed here, CEO can customzie a package to meet your specific needs Fiber coupled arrays feature high brightness fiber coupling, small footprint and very high power in passively cooled packages. They deliver 6W to 120W of laser power through 0.22 NA multimode optical fibers with 100µm to 1000 µm core. Silver Bullet diode laser submodules (ASMs) are offered with optional soldering kits. CEO® can also attach Silver Bullets to customer-supplied heat exchanger to make completely packaged laser diode arrays. Extreme care should be taken when handling these components. We recommend that they be only used by customers who are experienced in the handling and packaging of laser diode bars. A laser diode is a laser where the active medium is a semiconductor similar to that found in a light-emitting diode. The most common and practical type of laser diode is formed from a p-n junction and powered by injected electric current. These devices are sometimes referred to as injection laser diodes to distinguish them from (optically) pumped laser diodes, which are more easily produced in the laboratory.

RUBY LASER

2009-07-02T16:08:00.000-07:00

The first laser (which is the abbreviation of the words Light Amplification by Stimulated Emission of Radiation) was created in 1961 by Theodore Maiman (b.1927) at the Hughes Research Laboratories. He used a rod of synthetic ruby as the lasing medium. The crystalline structure of ruby is similar to the one of corundum, i.e. a crystal of aluminum oxide (Al2O3), in which the small part of atoms of aluminum (about 0,05 %) is replaced with ions Cr +++. Ruby rod is illuminated by intense impulse of light, which is generated by helical xenon discharge lamp as shown in animation. The ends of ruby rod are highly polished and silvered to serve as laser mirrors. The impulse of light creates the inverse population of electrons in ruby rod and due to the presence of mirrors the laser generation is excited. The duration of the laser impulse is a little bit shorter than the pump impulse of the flash lamp.
A short while after the initial announcement of the first successful optical laser, other labs around the world jumped on the bandwagon trying out many different substrates and ions such as rare earths like Nd, Pr, Tm, Ho, Er, Yb, Gd even Uranium was successfully lased ! Many different substrates were tried such as Yttrium Aluminum Garnet (YAG), glass (which was easier to manufacture), CaF2. As manufacturing techniques improved these lasers rapidly made the transition from the lab bench to commercial applications.

HAIR TRANSPALATION

2009-07-02T16:05:00.000-07:00

Follicular Hair Transplantation

Follicular hair transplantation is a surgical procedure in which small plugs of hair-bearing skin containing 2 to 3 hair each are taken from the back or sides of the scalp and transferred to the bald area on the head. The area from which the grafts are taken (donor site) is first treated with a local anesthesia followed by removal of the desired number of hair grafts. The area that is to receive the grafts (recipient site) is similarly treated and the donor grafts are carefully placed into the prepared area in a pattern that matches the direction of the original hair. The transplants are spaced in such a way as to allow each to receive an adequate blood supply during the healing process. The procedure lasts for 2 to 3 hours depending upon the condition of the skin and extent of the area involved. One to three months later, the spaces between the new implants are filled in with new grafts. About six weeks after each transplant, the hair falls out. Approximately three months later, new hair appears and grows at a rate of one quarter to one-half inch a month.

What types of baldness can be helped by this procedure?

There are many causes for hair loss in men and women including high fever as a result of severe infection, thyroid disease, inadequate protein in the diet, certain medications, cancer treatments, childbirth, birth control pills and others. Many of these conditions are reversible and do not require hair transplantation. The most common type of baldness that is successfully treated with hair transplantation is male pattern baldness. This condition, inherited from either side of the family, starts when a person is in his or her teens, twenties or thirties. While women with this inherited tendency do not become bald, they can develop considerable thinning of the hair. Other types of baldness that respond to this procedure are those which have resulted from accidents, operations and inflammatory or infectious diseases of the scalp. Following the initial treatments, many patients who want to achieve greater density or refinement of the hairline will return for additional transplants.

COSMETIC LASER SURGERY

2009-07-02T15:48:00.000-07:00

Vitiligo (vit-ill-EYE-go) is a pigmentation disorder in which melanocytes (the cells that make pigment) in the skin, the mucous membranes (tissues that line the inside of the mouth and nose and genital and rectal areas), and the retina (inner layer of the eyeball) are destroyed. As a result, white patches of skin appear on different parts of the body. The hair that grows in areas affected by vitiligo usually turns white.

The cause of vitiligo is not known, but doctors and researchers have several different theories. One theory is that people develop antibodies that destroy the melanocytes in their own bodies. Another theory is that melanocytes destroy themselves. Finally, some people have reported that a single event such as sunburn or emotional distress triggered vitiligo; however, these events have not been scientifically proven to cause vitiligo.

Who Is Affected by Vitiligo?

About 1 to 2 percent of the world's population, or 40 to 50 million people, have vitiligo. In the United States, 2 to 5 million people have the disorder. Ninety-five percent of people who have vitiligo develop it before their 40th birthday. The disorder affects all races and both sexes equally.

THE MYSTERIES OF LASER

2009-07-02T15:44:00.000-07:00

For Librarians
Because librarians want their users to access the best possible content as a result of their research, they invest in quality databases such as those offered on EBSCOhost®. Difficulty arises when researchers search the open Web where distinguishing between quality content and less credible content can be a challenge. EBSCOhost Connection is designed to bridge the gap between commercial search engines (e.g. Google, Yahoo, MSN, etc) and the valuable content of EBSCOhost. It is intended to promote the EBSCOhost content purchased by public libraries, schools, universities and other EBSCO customers by infusing brief citation-only records from EBSCOhost databases within commercial search engine result lists. Users would then click on the EBSCOhost record and be appropriately directed to the database pages within their library's EBSCOhost profile. Users will also realize through an on-screen brand, that the content is brought to them courtesy of their library (including the appropriate library's name).

The basic objective of EBSCOhost Connection is to help researchers find more quality results if they are searching the Web by directing them into EBSCOhost. This optional service is free to all EBSCOhost database customers, and activated only at the discretion of the library.

MASER

2009-07-02T15:41:00.000-07:00

In 1954, Charles Townes and Arthur Schawlow invented the maser (microwave amplification by stimulated emission of radiation), using ammonia gas and microwave radiation - the maser was invented before the (optical) laser. The technology is very close but does not use a visible light. On March 24, 1959, Charles Townes and Arthur Schawlow were granted a patent for the maser. Patent Number(s) 2,879,439; 2,929,922Theory of the Laser:
In 1958, Charles Townes and Arthur Schawlow theorized (but did not build) about a visible laser, an invention that would use infrared and/or visible spectrum light.
Charles Townes - Biography:
Charles Townes was born in Greenville, South Carolina on July 28 1915. During World War II, Townes was employed at Bell Telephone Laboratories Inc., where he worked on radar bombing systems. Beginning in 1948, he began work on the maser at Columbia University. Charles Townes was the director of research at the Institute for Defense Analysis in Washington, D.C. from 1959 to 1961. After that, he became the professor of physics at Massachusetts Institute of Technology. In 1964, Townes was awarded the Nobel Prize for Physics for his research in quantum electronics.
Arthur Schawlow was born in Mount Vernon, New York, on May 5 1921. In 1941, he received a bachelor's degree in physics and mathematics from the University of Toronto. He later his master's degree and Ph.D. in physics from the same university. Arthur Schawlow met Charles Townes at Columbia University, where he was doing research. In 1981, Schawlow was awarded the Nobel Prize for Physics for his research in laser spectroscopy

LPKF LASER PLASTIC WELDING

2009-07-02T15:32:00.000-07:00

The Process:
Transmission laser welding creates a perfect and reliable connection. In this process, two plastic parts are joined, each possessing different absorptive characteristics. The laser penetrates the top layer, which is transparent to that wavelength, but is absorbed by the bottom layer. The surface of the bottom layer melts, which in turn melts the adjoining surfaces of the top layer and both surfaces bind to each other

Clean and safe joining of components
Welding plastics via laser is especially suited for delicate components, because there is no mechanical motion and the thermal reaction is minimal. This makes the technique ideal for a wider range of possible applications in such industries as automotive, medical, consumer electronics, and theThe LQ-Power is the latest evolution of laser plastic welding, available now as a turnkey solution. LPKF’s fundamental understanding of the process and years of experience in mechanical and automation engineering stand behind this high quality laser plastic welding system. The system meets even the most rigorous industrial demand and quality requirements.

The LQ-Power handles work pieces as large as 6.3” x 6.3” x 3.9” (160 x 160 x 100mm). Although the factory configuration is ideal for manual feeding from a standing or sitting position, the dual stations assure short process times. The system an also be configured at the factory for automated feeding for pick & place systems.

•Full size PCB format Table size 25” x 22” (640 x 560 mm)
•Standardized feed adapters reduce typical changeover time to less than ten minutes
•Unit can be loaded and unloaded during a welding cycle – reducing cycle time
food industry.

BRAIN TUMOR

2009-06-30T11:26:00.000-07:00

This chapter contains information detailing cancers by type. As our focus is on the biology of the cancers and their treatments, we do not give detailed treatment guidelines. Instead, we link to organizations in the U.S. that generate the treatment guidelines.

Thank you for your patience as we work to continue expanding this chapter with additional cancer types. If the cancer in which you are interested is not yet presented, please check back because we will be adding new cancer types regularly.

•Breast
•Cervical
•Colon & Rectal (Colorectal)
•Leukemia
•Lymphoma
•Lung
•Multiple Myeloma
•Pancreatic
•Prostate
The chromosomes within our cells contain an enormous amount of information. It is estimated that humans have somewhere around 30,000 genes. Each gene codes for an RNA molecule that is either used directly or used as a guide for the formation of a protein such as the insulin shown earlier. Information in our cells generally flows in a predictable order from the storage form of the information (DNA) through the working form (RNA) into the final product (protein). This pathway is used by all organisms and is diagrammed below.

As shown, DNA is used as a model or template for the production of more DNA. This process, known as replication, will be addressed in the next chapter on cell division.

The process in which particular sections of DNA (genes) are used to produce RNA is known as transcription. We will cover transcription in some detail because alterations in the transcription of certain genes are very important in the development of cancer.

The set of genes that are 'on' at any given time is critical. The variable environment in which we live means that different genes need to be 'on' at different times. For example, if a meal contains large amounts of lactose, a sugar found in milk, then our bodies respond by turning on (transcribing) the genes that lead to the production of enzymes that break down lactose. If a different sugar or nutrient is present, the correct genes need to be turned on to process it.
•Skin
•Stomach (Gastric)

kidney center

2009-06-30T05:42:00.000-07:00

The Kidney Centre Post Graduate Training Institute is committed to provide quality renal health care services.

Our Services

Equipped with the latest state-of-the-art machinery, TKC is fully trained to handle all kinds of nephro-urological emergencies.
Equipped with the latest state-of-the-art machinery including two emergency dialysis machines, one emergency surgery theatre and 10 day-care beds, the Emergency Room is staffed with doctors and paramedical, fully trained to handle all kinds of nephro-urological emergencies.

All necessary investigations are carried out in E.R and the patient may have to stay for a short while or up to 12 hours. If required the patient is transferred to the in-patient ward.

The reception at the Emergency Room provides information about registration, discharge or transfer to the ward.

Lithotripsy

Lithotripsy is a non-surgical procedure of breaking kidney ureter and urinary bladder stones through shockwaves into small fragments that are subsequently passed out in the urine.

The Kidney Centre is equipped with the most advanced lithotripter with full back-up facilities like DJS insertion, push back and URS.This is a day care procedure and the patient is able to leave the hospital the same day after treatment.

LASIK

2009-06-29T11:36:00.000-07:00

Rated as one of India 's leading Eye Hospitals, Rushabh offers the most advanced Eye Care Treatment and Technology in India today. We also combine the expertise of our team which includes specialist Eye Surgeons who are highly experienced in their specialties of Cataract, Retina, Glaucoma and Laser Eye Surgeries.

Laser Vision Correction in India took a leap forward with the introduction of the Visx Star S4 at Rushabh. This Laser Technology, being the only one approved by NASA for its astronauts is the most preferred choice of Lasik Surgeries in the USA & Worldwide.

Our advanced Cataract, Retina Clinic and Glaucoma Clinic are equipped with the most sophisticated diagnostic & surgical technology. Our team will offer you the highest level of comfort & after care that your Eyes deserve. Trust and leave your Eye Care with us.

Our Mission Statement: is to give our patients the Best & Safest in eye care at most affordable rate & in a Warm friendly manner.

http://www.rushabheyehospital.com/#virtual_tour.htm

ALL ABOUT DISEASES

2009-06-29T11:10:00.000-07:00

Diseases: Curing attitudes of stigmatization

A disease is an illness that affects the body (a single area or the whole system) and/or mind within a single organism (World Health Organization). Basically when a person is in a diseased state, they are no longer classified by modern and traditional medical diagnosis as “healthy”. Some examples of common diseases worldwide are: Influenza A virus, Asthma, HIV/AIDS, HPV, Malaria, and Sickle Cell Anemia. In addition, diseases are generally classified into three categories, which include: Genetic, infectious, and non-infectious.

As is the case with most marginalized groups, people living with a disease(s) are often discriminated against on the basis of their illness. Some researchers...
The greatest challenge that the human race has ever faced still remains: to live in a world free of the threat of violence. Violence is not restricted to times of war; it exists everywhere: in homes, schools and communities. Where there is injustice, there is conflict.

Conflict is generally classified in terms of both violent and nonviolent conflict. Violent conflict is generally associated as the use of force as a means to an end, while nonviolent conflict usually involves peaceful negotiation between conflicting groups or even mediation by an external (outside) group in order to work toward a compatible goal or resolution. Over time, nonviolent conflicts can erupt into direct force if a reasonable compromise is not reached.

surgery

2009-06-29T10:56:00.000-07:00

we invites you to become a registered member. Benefits of membership include the most comprehensive information on surgical procedures for only $5 per visit or $100 for a year long membership. To choose the program that works for you, pick any procedure and select your choice on t--------------------------------------------------------------------------------

Chest

Anesthesia

Blood Transfusion - Transfusion of blood and blood products

Breast Surgery - For cancer

Cardiac Catheterization - For heart disease

Coronary Artery Bypass Graft - Surgery to improve blood flow to the heart

Diagnostic and Interventional Angiography

Esophagectomy - Removal of the esophagus

Heart Valve Surgery

Thoracotomy - Opening of the chest

hat page.

High blood pressure (HBP), blood pressure readings

2009-06-29T10:50:00.000-07:00

What Is High Blood Pressure?
High blood pressure (HBP) is a serious condition that can lead to coronary heart disease, heart failure, stroke, kidney failure, and other health problems.

"Blood pressure" is the force of blood pushing against the walls of the arteries as the heart pumps out blood. If this pressure rises and stays high over time, it can damage the body in many ways.

Overview
About 1 in 3 adults in the United States has HBP. HBP itself usually has no symptoms. You can have it for years without knowing it. During this time, though, it can damage the heart, blood vessels, kidneys, and other parts of your body.

This is why knowing your blood pressure numbers is important, even when you're feeling fine. If your blood pressure is normal, you can work with your health care team to keep it that way. If your blood pressure is too high, you need treatment to prevent damage to your body's organs.

Blood Pressure Numbers
Blood pressure numbers include systolic (sis-TOL-ik) and diastolic (di-a-STOL-ik) pressures. Systolic blood pressure is the pressure when the heart beats while pumping blood. Diastolic blood pressure is the pressure when the heart is at rest between beats.

You will most often see blood pressure numbers written with the systolic number above or before the diastolic, such as 120/80 mmHg. (The mmHg is millimeters of mercury—the units used to measure blood pressure.)

The table below shows normal numbers for adults. It also shows which numbers put you at greater risk for health problems. Blood pressure tends to goes up and down, even in people who have normal blood pressure. If your numbers stay above normal most of the time, you're at risk.

Categories for Blood Pressure Levels in Adults (in mmHg, or millimeters of mercury)
Category Systolic
(top number) Diastolic
(bottom number)
Normal Less than 120 And Less than 80
Prehypertension 120–139 Or 80–89
High blood pressure
Stage 1 140–159 Or 90–99
Stage 2 160 or higher Or 100 or higher

The ranges in the table apply to most adults (aged 18 and older) who don't have short-term serious illnesses.

All levels above 120/80 mmHg raise your risk, and the risk grows as blood pressure levels rise. "Prehypertension" means you're likely to end up with HBP, unless you take steps to prevent it.

If you're being treated for HBP and have repeat readings in the normal range, your blood pressure is under control. However, you still have the condition. You should see your doctor and stay on treatment to keep you blood pressure under control.

Your systolic and diastolic numbers may not be in the same blood pressure category. In this case, the more severe category is the one you're in. For example, if your systolic number is 160 and your diastolic number is 80, you have stage 2 HBP. If your systolic number is 120 and your diastolic number is 95, you have stage 1 HBP.

If you have diabetes or chronic kidney disease, HBP is defined as 130/80 mmHg or higher. HBP numbers also differ for children and teens. (For more information, see "How Is High Blood Pressure Diagnosed?")

Outlook
Blood pressure tends to rise with age. Following a healthy lifestyle helps some people delay or prevent this rise in blood pressure.

People who have HBP can take steps to control it and reduce their risks for related health problems. Key steps include following a healthy lifestyle, having ongoing medical care, and following the treatment plan that your doctor prescribes.

November 2008

cancer skin cancer and other cancer research

2009-06-29T10:41:00.000-07:00

Were you looking for information about Skin Cancer? Skin canser is a common misspelling of skin cancer.

Skin cancer, the most common cancer in the United States, begins in the outer layer of skin (the epidermis). Among the possible symptoms are sores that do not heal and areas on the skin that are similar to a scar and firm to the touch. Risk factors for this type of cancer include exposure to radiation, having a fair complexion, and prolonged exposure to natural or artificial sunlight.

The best way to prevent this disease is to protect yourself from the sun and other sources of UV radiation. Sunscreen, especially broad-spectrum sunscreen (to filter UVB and UVA rays) with a sun protection factor (SPF) of at least 15, may help prevent skin cancer. However, it is still important to avoid the sun and wear clothing to protect your skin. Although some types of this cancer are curable, people who have had the disease previously have a greater chance of developing another skin cancer.

(Click Skin Cancer for more information on the causes and symptoms, as well as the risk factors that increase your chances of developing this disease. You can also click on any of the links in the box to the right for more specific information.)

Genetic determination of eye color

2009-06-27T11:26:00.000-07:00

Eye color
From Wikipedia, the free encyclopedia
Jump to: navigation, search
Eye color is a polygenic phenotypic character and is determined by the amount and type of pigments in the eye's iris.[1][2]

Humans and animals have many phenotypic variations in eye color, as blue, brown, green and others. These variations constitute phenotypic traits.[3]

In human eyes, these variations in color are attributed to varying ratios of eumelanin produced by melanocytes in the iris.[2] The brightly colored eyes of many bird species are largely determined by other pigments, such as pteridines, purines, and carotenoids.[4]

Three main elements within the iris contribute to its color: the melanin content of the iris pigment epithelium, the melanin content within the iris stroma, and the cellular density of the iris stroma.[5] In eyes of all colors, the iris pigment epithelium contains the black pigment, eumelanin.[2][5] Color variations among different irises are typically attributed to the melanin content within the iris stroma.[5] The density of cells within the stroma affects how much light is absorbed by the underlying pigment epithelium.[5] OCA2 gene polymorphism, close to proximal 5′ regulatory region, explains most human eye-color variation.[6]
Genetic determination of eye color
Eye colors can range from the most common color, brown, to the least common, green. Rare genetic mutations can even lead to unusual eye colors: black, red, or the appearance of violet. Eye color is an inherited trait influenced by more than one gene.[7][8] These genes are being sought using associations to small changes in the genes themselves and in neighboring genes. These changes are known as single nucleotide polymorphisms or SNPs. The actual number of genes that contribute to eye color is currently unknown, but there are a few likely candidates. A study in 2009 found that it was possible to predict the color of eyes in Rotterdam with more than 90% accuracy for brown and blue, using just six SNPs (from six genes). [9]

The gene OCA2 (OMIM: 203200), when in a variant form the gene causes the pink eye color and hypopigmentation common in human albinism. (The name of the gene is derived from the disorder it causes, oculocutaneous albinism type II.) Different SNPs within OCA2 are strongly associated with blue and green eyes as well as variations in freckling, mole counts, hair and skin tone. The polymorphisms may be in an OCA2 regulatory sequence, where they may influence the expression of the gene product, which in turn affects pigmentation.[6] A specific mutation within the HERC2 gene, a gene that regulates OCA2 expression, is partly responsible for blue eyes.[10] Other genes implicated in eye color variation are: SLC24A4 [11] and TYR.[11]

Blue eyes with a brown spot, green eyes and gray eyes are caused by an entirely different part of the genome. As Eiberg said: "The SNP rs12913832 [of the Herc2 gene] is found to be associated with the brown and blue eye color, but this single DNA variation cannot explain all the brown eye color variation from dark brown over hazel to blue eyes with brown spots."

[edit] Classification of colors

The perception of color depends upon various factors. These are the same eyes; however, depending on the light and surrounding hues, the eye color can appear quite different.Iris color can provide a large amount of information about an individual and a classification of various colors may be useful in documenting pathological changes or determining how a person may respond to various ocular pharmaceuticals.[12] Various classification systems have ranged from a basic light or dark description to detailed gradings employing photographic standards for comparison.[12] Others have attempted to set objective standards of color comparison.[13]

As the perception of color is dependent on viewing conditions (e.g., the amount and type of illumination, as well as the hue of the surrounding environment), so is the perception of eye color.[14]

Eye color exists on a continuum from the darkest shades of brown to the lightest shades of blue.[7] Seeing the need for a standardized classification system that was simple, yet detailed enough for research purposes, Seddon et al. developed a graded one based on the predominant iris color and the amount of brown or yellow pigment present.[15] There are 3 true colors in the eyes that determine the outward appearance; brown, yellow, and blue. How much of each color one has determines the appearance of the eye color. The color of the eyes in turn depends on how much of these colors are present. For example, green eyes have blue and some yellow, making them appear green. Brown eyes appear brown because most of the eye contains the brown color. The above is true only for Homo sapiens; iris color varies greatly in the rest of the animal world. For example, instead of blue in humans, autosomal recessive color in the skink Corucia zebrata is black, whereas the autosomal dominant color is yellow-green.[16]

[edit] Changes in eye color throughout life
In European populations, children are most commonly born with unpigmented (blue) eyes. As the child develops, melanocytes, cells found within the iris of human eyes (as well as skin and hair follicles) slowly begin to produce melanin. Because melanocyte cells continually produce pigment, eye color, in theory, can be changed.

Changes (lightening or darkening) of eye colors during puberty, early childhood, pregnancy, and sometimes after serious trauma (like heterochromia), do represent cause for plausible argument to state that some eyes can or do change, based on chemical reactions and hormonal changes within the body. Most eye changes happen when the newborn baby is around one year old, although it can happen up to 3 years of age.[17]

Studies on Caucasian twins, both fraternal and identical, have shown that eye color over time can be subject to change, and major demelanization of the iris may also be genetically determined. Most eye color changes have been observed or reported as Caucasians with hazel eyes.[18]

[edit] Eye color chart (Martin-Schultz scale)
Carleton Coon created this chart by the Martin-Schultz scale often used in physical anthropology.

I.Light eyes
Eyes light and light mixed are 16-12 in Martin scale.

Light
Grey, blue, green.
Light-mixed
a.Very light-mixed (blue with grey or green or green with grey)
b.Light-mixed (light or very light-mixed with small admixture of brown pigment)
II.Mixed eyes
Mixed
12-6 in Martin scale. Mixture of light eyes (blue, grey or green) with brown pigment when light and brown pigment are the same level. Some of mixed eyes are accept to light-pigment eyes.
III.Dark eyes
Dark-mixed
Hazel. 6-4 in Martin scale. Brown with small admixture of light pigment.
Dark
4-1 in Martin scale. Brown (light brown and dark brown) and very dark brown (black).

[edit] Blue

A blue irisBlue eyes contain low amounts of melanin within the iris stroma; longer wavelengths of light tend to be absorbed by the underlying iris pigment epithelium, and shorter wavelengths are reflected and undergo Rayleigh scattering.[5] The type of melanin present is eumelanin.[19] The inheritance pattern followed by blue eyes is considered similar to that of a recessive trait, however it's a polygenic trait (meaning that it's controlled by the interactions of several genes, not just one).[8] Eiberg and colleagues showed in a study published in Human Genetics that a mutation in the 86th intron of the HERC2 gene, which is hypothesized to interact with the OCA2 gene promoter, reduced expression of OCA2 with subsequent reduction in melanin production.[20] The authors concluded that the mutation may have arisen in a single individual in the Near East or around the Black Sea region 6,000-10,000 years ago during the neolithic revolution,[21][22] perhaps suggesting that all people with pure blue eyes are more closely related. However, blue eyes with brown spots around the pupil are not related to this mutation.

Blue eyes are most common in Northern and Central Europe and to a lesser degree in Southern Europe and also North America; Though they can also be found in Central Asia such as Afghanistan. [23] they're also found in parts of North Africa,[24] West Asia, and South Asia, in the northern areas in particular. However blue eyes are not found within the population of East Asia, due to the major pre-dominance of the brown eye gene in the area. A 2002 study found the prevalence of blue eye color among Caucasians in the United States to be 33.8 percent for those born from 1936 through 1951 compared with 57.4 percent for those born from 1899 through 1905.[8]

Blue eyes have become increasingly rare among American children with only 1 out of every 6 – 16.6 percent which is 49.8 million out of 300 million (22.4% of white Americans) of the total United States population having blue eyes.[25][26] The plunge in the past few decades has taken place at a remarkable rate. A century ago, 80 percent of people married within their ethnic group. Blue eyes, a genetically recessive trait, were routinely passed down, especially among people of Scottish, English, Irish, Western and Northern Slavic, and Northern European ancestry.[25][26][27] In the 1930s, eugenicists used the disappearance of blue eyes as a rallying cry to support immigration restrictions. They went so far as to map the parts of the country with the highest and lowest percentage of blue-eyed people.

The outer surface of the iris of a blue eyed person is actually clear, lacking the outer layer of pigmentation that is found in brown eyes. Their color is caused by the inner layer of pigmentation and the semi-opaque fibrous tissues which lay between the two layers.[28]

[edit] Mate preference
Some studies have suggested that blue eyed men prefer blue eyed women due to the trait's recessive inheritance.[29] Under this theory, because blue eyed couples are likely to produce blue eyed offspring, males are more confident in the child's paternity.

[edit] Brown

Brown human iris
Amber human irisBrown eyes are predominant in humans[30] and, in most populations and countries, it is (with few exceptions) the only iris color present.[31] It is less common in countries around the Baltic Sea and in Scandinavia. Dark pigment of brown eyes are most common and with a few exceptions the only color among the population of East Asia. In humans brown eyes contain large amounts of melanin within the iris stroma, which serves to absorb light at both shorter and longer wavelengths. Brown eyes are the most common eye color, with over half of the world's population having them (Including hazel and amber eyes the ratio can reach over 90%).

Amber

Human amber eyes displaying the yellow pigments.Amber eyes are of a solid color and have a strong yellowish/golden and russet/coppery tint. This might be due to the deposition of the yellow pigment called lipochrome in the iris (which is also found in green and violet eyes).[32][33] Amber eyes should not be confused with hazel eyes; although hazel eyes may contain specks of amber or gold, they usually tend to comprise many other colors, including green, brown and orange. Also, hazel eyes may appear to shift in color and consist of flecks and ripples; while amber eyes are of a solid gold hue.

The eyes of some pigeons contain yellow fluorescing pigments known as pteridines.[34] The bright yellow eyes of the Great Horned Owl are thought to be due to the presence of the pteridine pigment xanthopterin within certain chromatophores (called xanthophores) located in the iris stroma.[35] In humans, yellowish specks or patches are thought to be due to the pigment lipofuscin, also known as lipochrome.[36]

[edit] Gray

A steel blue-gray eye
Gray eye under magnification, exhibiting small amounts of yellow.Gray eyes have less melanin than blue eyes,[citation needed] even though they are considered a darker shade of blue (like blue-green). Gray eyes are most common in European Russia, Finland and the Baltic States.[citation needed] Under magnification, gray eyes exhibit small amounts of yellow and brown color in the iris. Ultimately there are at least two things that could determine gray eye color. The first is the amount of melanin made. And the second is the density of the proteins in the stroma. [37]

A gray iris may indicate the presence of a uveitis. However, other visual signs make a uveitis obvious. Gray iris color, as well as blue, are at increased risk of uveal melanoma. [38]

Visually, gray eyes often tend to appear to change between the shades of blue, green and gray; this is because gray eyes are extremely light, as mentioned before. The color change for gray eyes is usually influenced by the lighting and the colors in the surroundings (such as clothes, makeup, etc.).

The Greek goddess Athena was renowned for having owl-gray or sea-gray eyes (in Greek, γλαυκῶπις – glaukōpis).[39]

[edit] Green

Light green eyes
Olive green eyesGreen eyes are the product of low to moderate amounts of melanin and probably represent the interaction of multiple variants within the OCA2 and in other genes, including perhaps the red-hair gene.[40] They are most common in Northern Europe and Central Europe [41][42].

A study of Icelandic and Dutch adults found that green eyes are much more prevalent in women than in men.[43] Almost 92% of the population in Iceland has either green or blue eye color.[44]

Among White Americans, green eyes are most common among those of Celtic and Germanic ancestry, about 16 percent [45] . This eye color is the least common found among humans, with the exceptions of rare eye mutations, that can create black, red, and other eye colors.

[edit] Hazel

This eye shows a mixture of brown, green, and amber colors.Hazel eyes are due to a combination of Rayleigh scattering and a more than moderate amount of melanin in the iris' anterior border layer.[5][36] Hazel eyes often appear to shift in color from a light brown to a medium golden-dark green. A number of studies using three-point scales have assigned hazel to be the medium-color between the lightest shade of blue and darkest shade of brown. Hazel mostly consists of Brown and Green. The dominant color in the eye can either be green or brown.[46][47][48][49][50][51][52] This can sometimes produce a multicolored iris, i.e., an eye that is light brown near the pupil and charcoal or amber/dark green on the outer part of the iris (and vice versa) when observed in sunlight. Hazel is commonly found in Europe, some regions of the Middle East, Americas, parts of Central Asia and parts of South Asia.

Definitions of the eye color hazel vary: it is sometimes considered to be synonymous with light-brown and gold.[46][48][51][53][54][55][56][57][58] In North America, hazel is often used to describe eyes that appear to change color.

[edit] Red
The eyes of a person with albinism may appear red under certain lighting conditions due to the very low quantities of melanin.[59] True red eyes also exist in albinistic and even some non-albinistic populations, but are very rare. Only about 20 cases of natural red eyes are recognized throughout the world.[citation needed]

[edit] Violet
The appearance of violet eyes is thought to occur from the mixing of red and blue reflections.[60] Some albinos have eyes that appear violet.[61] Violet eyes are genetically similar to blue eyes (i.e., they are a reflection, pigment, or variant of blue).[citation needed] Violet eyes are extremely rare; some people remain convinced that it is impossible to have violet colored eyes. However, violet eyes are commonly found in a few remote and high altitude areas of northern Kashmir and remote areas in Afghanistan.[citation needed]

Elizabeth Taylor is occasionally described as having violet eyes.

[edit] Medical implications
Those with lighter iris color have been found to have a higher prevalence of age-related macular degeneration (ARMD) than those with darker iris color;[50] lighter eye color is also associated with an increased risk of ARMD progression.[62] An increased risk of uveal melanoma has been found in those with blue, green or gray iris color.[38][44] Additionally, a recent study suggests that people with dark brown eyes are at increased risk of developing cataracts, and therefore should protect their eyes from direct exposure to sunlight.[63]

Eye color may also be symptomatic of disease. Aside from the iris, yellowing of the whites of the eyes is associated with jaundice and symptomatic of liver disease, including cirrhosis, hepatitis and malaria.

[edit] Anomalous conditions

Aniridia: Eyes wherein the irises are not present; the eyes appear to be two large pupils.
[edit] Aniridia
Main article: Aniridia
Aniridia is a congenital condition characterized by an extremely underdeveloped iris which appears absent on superficial examination.[64]

[edit] Ocular albinism and eye color
Normally, there is a thick layer of melanin on the back of the iris. Even people with the lightest blue eyes, with no melanin on the front of the iris at all, have dark brown coloration on the back of it, to prevent light from scattering around inside the eye. In those with milder forms of albinism, the color of the irises is typically blue, but can vary from blue to brown. In severe forms of albinism, there is no pigment on the back of the iris, and light from inside the eye can pass through the iris to the front. In these cases, the only color seen is the red from the hemoglobin of the blood in the capillaries of the iris. Such albinos have pink eyes, as do albino rabbits, mice, or any other animal with total lack of melanin. Transillumination defects can almost always be observed during an eye examination due to lack of iridial pigmentation.[65] The ocular albino also lacks normal amounts of melanin in the retina as well, which allows more light than normal to reflect off the retina and out of the eye. Because of this, the pupillary reflex is much brighter in the albino, and this can increase the red eye effect in photographs.

[edit] Heterochromia

An example of complete heterochromia. The subject has one brown and one hazel eye. The subject also appears to have a faint star pattern in the hazel iris.
An example of sectoral heterochromia. The subject has a blue iris with a brown section.Main article: Heterochromia
Heterochromia (also known as a heterochromia iridis or heterochromia iridium) is an ocular condition in which one iris is a different color from the other iris (complete heterochromia), or where the part of one iris is a different color from the remainder (partial heterochromia or sectoral heterochromia). It is a result of the relative excess or lack of pigment within an iris or part of an iris, which may be inherited or acquired by disease or injury.[66] This uncommon condition usually results due to uneven melanin content. A number of causes are responsible, including genetics such as chimerism, Horners Syndrome and Waardenburg syndrome. A common cause in females with heterochromia is X-inactivation, which can result in a number of heterochromatic traits, such as calico cats. Trauma and certain medications, such as some prostaglandin analogues can also cause increased or decreased pigmentation in one eye. On occasion, the condition of having two different colored eyes is caused by blood staining the iris after sustaining injury.

[edit] Eye color change
Often, newborns have blue eyes, which change to green, hazel, light brown or dark brown. This is possibly the origin of the idiom being blue-eyed (i.e., naïve; gullible) or having baby blues, or striking blue eye color.

It's thought that exposure to light after birth triggers the production of melanin in the iris of the eye. By three years of age, the eyes produce and store enough melanin to indicate their natural shade. While changes in eye color of infants are more common, even in adults, eye color changes are seen, most often as a result of exposure to the sun. Sunlight triggers melanin production in the eye, as it does to the skin.

Children'seye injuries

2009-06-27T11:02:00.000-07:00

Since 1908, Prevent Blindness America has been the nation's leading volunteer eye health and safety organization with the sole mission of preventing blindness and preserving sight.Sixth Annual Investigator Awards Announced

Since the program's inception, Prevent Blindness America and its affiliates have awarded more than $500,000 to projects through its Investigator Award program.

Prevent Blindness America has released a new report estimating the costs associated with adult vision problems in the United States. The Economic Impact of Vision Problems: The Toll of Major Adult Eye Disorders, Visual Impairment, and Blindness on the U.S. Economy provides data on the individual and economic cost of eye disease and vision impairment.

Find the information you need to take care of your vision for life.
Thousands of eye accidents happen each day; 90 percent of these are preventable with the use of appropriate safety eyewear.

Because there are good eye safety regulations in the workplace, the home is the source of the fastest-growing number of eye injuries. Eye injuries are almost as great a danger to bystanders as the people using dangerous tools or chemicals in the home. Good eye protection is just as important for those watching you work as for the workers themselves