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Laser Photocoagulation
Laser coagulation or laser photocoagulation surgery is used to treat a number of eye diseases and has become widely used in recent decades. During the procedure, a laser is used to finely cauterize ocular blood vessels to attempt to bring about various therapeutic benefits. The procedure is used mostly to close blood vessels in the eye, in certain kinds of diabetic retinopathy; it is no longer used in age-related macular degeneration in favor of anti-VEGF drugs. Medical uses Diabetic retinopathy The American Academy of Ophthalmology practice guidelines recommend laser coagulation for people who have both mild to moderate nonproliferative diabetic retinopathy (NPDR) and clinically significant macular edema outside the fovea; treatment with anti-VEGF drugs is better than laser coagulation for clinically significant macular edema in the fovea. For people with severe NPDR and no macular edema, the AAO recommends laser photocoagulation for the whole retina; when there is macular edem ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Laser
A laser is a device that emits light through a process of optical amplification based on the stimulated emission of electromagnetic radiation. The word "laser" is an acronym for "light amplification by stimulated emission of radiation". The first laser was built in 1960 by Theodore H. Maiman at Hughes Research Laboratories, based on theoretical work by Charles Hard Townes and Arthur Leonard Schawlow. A laser differs from other sources of light in that it emits light which is ''coherent''. Spatial coherence allows a laser to be focused to a tight spot, enabling applications such as laser cutting and lithography. Spatial coherence also allows a laser beam to stay narrow over great distances (collimation), enabling applications such as laser pointers and lidar (light detection and ranging). Lasers can also have high temporal coherence, which allows them to emit light with a very narrow spectrum. Alternatively, temporal coherence can be used to produce ultrashort pulses of ligh ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Colon Cancer
Colorectal cancer (CRC), also known as bowel cancer, colon cancer, or rectal cancer, is the development of cancer from the colon or rectum (parts of the large intestine). Signs and symptoms may include blood in the stool, a change in bowel movements, weight loss, and fatigue. Most colorectal cancers are due to old age and lifestyle factors, with only a small number of cases due to underlying genetic disorders. Risk factors include diet, obesity, smoking, and lack of physical activity. Dietary factors that increase the risk include red meat, processed meat, and alcohol. Another risk factor is inflammatory bowel disease, which includes Crohn's disease and ulcerative colitis. Some of the inherited genetic disorders that can cause colorectal cancer include familial adenomatous polyposis and hereditary non-polyposis colon cancer; however, these represent less than 5% of cases. It typically starts as a benign tumor, often in the form of a polyp, which over time becomes cancerous. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
List Of Laser Articles
This is a list of laser topics. A * 3D printing, additive manufacturing * Abnormal reflection * Above-threshold ionization * Absorption spectroscopy * Accelerator physics * Acoustic microscopy * Acousto-optic deflector * Acousto-optic modulator * Acousto-optical spectrometer * Acousto-optics * Active laser medium * Active optics * Advanced Precision Kill Weapon System * Advanced Tactical Laser * Afocal system * Airborne laser * Airborne wind turbine * Airy beam * ALKA * All gas-phase iodine laser * Ambient ionization * Amplified spontaneous emission * Analytical chemistry * Aneutronic fusion * Antiproton Decelerator * Apache Arrowhead * Apache Point Observatory Lunar Laser-ranging Operation * Arago spot * Argon fluoride laser * Argus laser * Asterix IV laser * Astrophysical maser * Atmospheric-pressure laser ionization * Atom interferometer * Atom laser * Atom probe * Atomic clock * Atomic coherence * Atomic fountain * Atomic line filter * Atomic ratio * Atomic spectros ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
University Of Hamburg
The University of Hamburg (german: link=no, Universität Hamburg, also referred to as UHH) is a public research university in Hamburg, Germany. It was founded on 28 March 1919 by combining the previous General Lecture System ('' Allgemeines Vorlesungswesen''), the Hamburg Colonial Institute ('' Hamburgisches Kolonialinstitut''), and the Academic College ('' Akademisches Gymnasium''). The main campus is located in the central district of Rotherbaum, with affiliated institutes and research centres distributed around the city-state. The university has been ranked in the top 200 universities worldwide by the ''Times Higher Education Ranking'', the Shanghai Ranking and the CWTS Leiden Ranking, placing it among the top 1% of global universities. Seven Nobel Prize winners and one Wolf Prize winner are affiliated with UHH. On a national scale, '' U.S. News & World Report'' ranks UHH 7th and ''QS World University Rankings'' 14th out of a total of 426 German institutions of higher educa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gerhard Meyer-Schwickerath
Gerhard Rudolph Edmund Meyer-Schwickerath (10 July 1920 – 20 January 1992) was German ophthalmologist university lecturer and researcher. He is known as the father of light coagulation which was the predecessor to many eye surgeries. Early life Gerhard Rudolph Meyer was born as the son of Edmund Meyer (1887–1973) and Josephine Meyer B. Schmitz (1890-1959) in Elberfeld, Germany. In 1935, the family also adopted surname of Edmund Meyer's mother, Julie Schwickerath (1860–1929) and henceforth Gerhard Rudolph Meyer was stylized as Meyer-Schwickerath. One year after Gerhard's birth, his younger brother, Klaus Meyer-Schwickerath, was born, who went on to study law and become a politician. After graduating from high school, Meyer-Schwickerath decided not to be a lawyer, contrary to the family tradition, because he did not want to defend Nazism. He opted to become a physician instead. He began his medical studies in 1940. During the World War II he worked as a medic. A knee injur ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hemorrhage
Bleeding, hemorrhage, haemorrhage or blood loss, is blood escaping from the circulatory system from damaged blood vessels. Bleeding can occur internally, or externally either through a natural opening such as the mouth, nose, ear, urethra, vagina or anus, or through a puncture in the skin. Hypovolemia is a massive decrease in blood volume, and death by excessive loss of blood is referred to as exsanguination. Typically, a healthy person can endure a loss of 10–15% of the total blood volume without serious medical difficulties (by comparison, blood donation typically takes 8–10% of the donor's blood volume). The stopping or controlling of bleeding is called hemostasis and is an important part of both first aid and surgery. Types * Upper head ** Intracranial hemorrhage – bleeding in the skull. ** Cerebral hemorrhage – a type of intracranial hemorrhage, bleeding within the brain tissue itself. ** Intracerebral hemorrhage – bleeding in the brain caused by the ruptu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Visual Acuity
Visual acuity (VA) commonly refers to the clarity of vision, but technically rates an examinee's ability to recognize small details with precision. Visual acuity is dependent on optical and neural factors, i.e. (1) the sharpness of the retinal image within the eye, (2) the health and functioning of the retina, and (3) the sensitivity of the interpretative faculty of the brain. The most commonly referred visual acuity is the far acuity (e.g. 6/6 or 20/20 acuity), which describes the examinee's ability to recognize small details at a far distance, and is relevant to people with myopia; however, for people with hyperopia, the near acuity is used instead to describe the examinee's ability to recognize small details at a near distance. A common cause of low visual acuity is refractive error (ametropia), errors in how the light is refracted in the eyeball, and errors in how the retinal image is interpreted by the brain. The latter is the primary cause for low vision in people with a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Argon Plasma Coagulation
Argon plasma coagulation (APC) is a medical endoscopic procedure used to control bleeding from certain lesions in the gastrointestinal tract. It is administered during esophagogastroduodenoscopy or colonoscopy. Medical use APC involves the use of a jet of ionized argon gas ( plasma) directed through a probe passed through the endoscope. The probe is placed at some distance from the bleeding lesion, and argon gas is emitted, then ionized by a high-voltage discharge (approx 6 kV). High-frequency electric current is then conducted through the jet of gas, resulting in coagulation of the bleeding lesion. As no physical contact is made with the lesion, the procedure is safe if the bowel has been cleaned of colonic gases, and can be used to treat bleeding in parts of the gastrointestinal tract with thin walls, such as the cecum. The depth of coagulation is usually only a few millimetres. APC is used to treat the following conditions: * angiodysplasias, anywhere in the GI tract * gastri ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Argon Laser
An ion laser is a gas laser that uses an ionized gas as its lasing medium. Like other gas lasers, ion lasers feature a sealed cavity containing the laser medium and mirrors forming a Fabry–Pérot resonator. Unlike helium–neon lasers, the energy level transitions that contribute to laser action come from ions. Because of the large amount of energy required to excite the ionic transitions used in ion lasers, the required current is much greater, and as a result all but the smallest ion lasers are water-cooled. A small air-cooled ion laser might produce, for example, 130 milliwatts of output light with a tube current of about 10 amperes and a voltage of 105 volts. Since one ampere times one volt is one watt, this is an electrical power input of about one kilowatt. Subtracting the (desirable) light output of 130 mW from power input, this leaves the large amount of waste heat of nearly one kW. This has to be dissipated by the cooling system. In other words, the power efficiency i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Potassium Titanyl Phosphate
Potassium is the chemical element with the symbol K (from Neo-Latin ''kalium'') and atomic number19. Potassium is a silvery-white metal that is soft enough to be cut with a knife with little force. Potassium metal reacts rapidly with atmospheric oxygen to form flaky white potassium peroxide in only seconds of exposure. It was first isolated from potash, the ashes of plants, from which its name derives. In the periodic table, potassium is one of the alkali metals, all of which have a single valence electron in the outer electron shell, that is easily removed to create an ion with a positive charge – a cation, that combines with anions to form salts. Potassium in nature occurs only in ionic salts. Elemental potassium reacts vigorously with water, generating sufficient heat to ignite hydrogen emitted in the reaction, and burning with a lilac- colored flame. It is found dissolved in sea water (which is 0.04% potassium by weight), and occurs in many minerals such as orthoclase, a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
YAG Laser )
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YAG laser may refer to two types of lasers that use yttrium aluminum garnet (YAG): * Nd:YAG laser (doped with neodymium) * Er:YAG laser (doped with erbium Erbium is a chemical element with the symbol Er and atomic number 68. A silvery-white solid metal when artificially isolated, natural erbium is always found in chemical combination with other elements. It is a lanthanide, a rare-earth element, or ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Large Intestine
The large intestine, also known as the large bowel, is the last part of the gastrointestinal tract and of the digestive system in tetrapods. Water is absorbed here and the remaining waste material is stored in the rectum as feces before being removed by defecation. The colon is the longest portion of the large intestine, and the terms are often used interchangeably but most sources define the large intestine as the combination of the cecum, colon, rectum, and anal canal. Some other sources exclude the anal canal. In humans, the large intestine begins in the right iliac region of the pelvis, just at or below the waist, where it is joined to the end of the small intestine at the cecum, via the ileocecal valve. It then continues as the colon ascending the abdomen, across the width of the abdominal cavity as the transverse colon, and then descending to the rectum and its endpoint at the anal canal. Overall, in humans, the large intestine is about long, which is about one-fi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
