Etymology.

The name "Yangon" () is derived from the combination of the Burmese words () and (), which mean 'enemies' and 'run out

History.

Early history.

Yangon was founded as "Dagon" in the early 11th century () by the Mon people, who dominated Lower Burma at that time. A Mon princess named Maha Dewi ruled Dagon as "Governor of Dagon" from 1364 to 1392. Her grandniece, Shin Sawbu (also known as Binnya Thau) ascended the throne of Hanthawaddy Kingdom in 1545 and would become the only female ruler in the recorded history of Myanmar.

Colonial Rangoon (1852–1948).

The British seized Yangon and all of Lower Burma in the Second Anglo-Burmese War of 1852, and subsequently transformed Yangon into the commercial and political hub of British Burma. After the war, the British moved the capital of British Burma from Moulmein (present-day Mawlamyine) to Yangon. Based on the design by army engineer Lt. Alexander Fraser, the British constructed a new city on a grid plan on delta land, bounded to the east by the Pazundaung Creek and to the south and west by the Yangon River. Yangon became the capital of all British-ruled Burma after the British had captured Upper Burma in the Third Anglo-Burmese War of 1885. By the 1890s Yangon's increasing population and commerce gave birth to prosperous residential suburbs to the north of Royal Lake (Kandawgyi) and Inya Lake. The

Contemporary Yangon (1948–present).

Soon after Burma's independence in 1948, many colonial names of streets and parks were changed to more nationalistic Burmese names. In 1989, the current military junta changed the city's English name to "Yangon", along with many other changes in English transliteration of Burmese names. (The changes have not been accepted by many Burmese who consider the junta unfit to make such changes, nor by many publications and news bureaus, including, most notably, the BBC and foreign nations including the United Kingdom and the United States.)

Geography.

Yangon is located in Lower Burma (Myanmar) at the convergence of the Yangon and Bago Rivers about 30 km(19 mi) away from the Gulf of Martaban at 16°48' North, 96°09' East (16.8, 96.15). Its standard time zone is UTC/GMT +6:30 hours. 23 meters above sea level.

Climate.

Yangon has a tropical monsoon climate under the Köppen climate classification system. The city features a lengthy wet season from May through October where a substantial amount of rainfall is received; and a dry season from

Cityscape.

Until the mid-1990s, Yangon remained largely constrained to its traditional peninsula setting between the Bago, Yangon and Hlaing Rivers. People moved in, but little of the city moved out. Maps from 1944 show little development north of Inya Lake and areas that are now layered in cement and stacked with houses were then virtual backwaters. Since the late 1980s, however, the city began a rapid spread north to where Yangon International Airport now stands. But the result is a stretching tail on the city, with the downtown area well removed from its geographic centre. The city's area has steadily increased from in 1901 to in 1940 to in 1974, to in 1985, and to in 2008.

Architecture.

Downtown Yangon is known for its leafy avenues and fin-de-siècle architecture. The former British colonial capital has the highest number of colonial period buildings in south-east Asia. Downtown Yangon is still mainly made up of decaying colonial buildings. The former High Court, the former Secretariat buildings, the former St. Paul's English High School and the Strand Hotel are excellent examples of the bygone era. Most downtown buildings from this era are four-story mix-use (residential and commercial) buildings with ceilings, allowing for the construction of mezzanines. Despite their less-than-perfect conditions, the buildings remain highly sought after and most expensive in the city's property market.  In 1996, the Yangon City Development Committee created a Yangon City Heritage List of old buildings and structures in the city that cannot be modified or torn down without approval. In 2012, the city of Yangon imposed a 50-year moratorium on demolition of buildings older than 50 years. The Yangon Heritage Trust, an NGO started by Thant Myint-U, aims to create heritage areas in Downtown, and attract investors

Road layout.

Downtown Yangon's road layout follows a grid pattern, based on four types of roads:  The east-west grid of central was laid out by British military engineers Fraser and Montgomerie after the Second Anglo-Burmese War. The city was later developed by the Public Works Department and Bengal Corps of Engineers. The pattern of south to north roads is as follows: one broad wide broad road, two narrow streets, one mid-size

Parks and gardens.

The largest and best maintained parks in Yangon are located around Shwedagon Pagoda. To the south-east of the gilded stupa is the most popular recreational area in the city – Kandawgyi Lake. The 150-acre (61-ha) lake is surrounded by the 110-acre (45-ha) Kandawgyi Nature Park, and the 69.25-acre (28-ha) Yangon Zoological Gardens, which consists of a zoo, an aquarium and

Administration.

Yangon is administered by the Yangon City Development Committee (YCDC). YCDC also coordinates urban planning. The city is made up of 33 townships and is part of Yangon Region. Yangon Region is divided into four districts, which overlap with the city's

Transport.

Yangon is Burma's main domestic and international hub for air, rail, and ground transportation.

Air.

Yangon International Airport, located 12 miles (19 km) from the centre, is the country's main gateway for domestic and international air travel. The airport has three terminals, known as T1, T2 and T3 which is also

Railways.

Yangon Central Railway Station is the main terminus of Myanmar Railways' rail network whose reach covers Upper Myanmar (Naypyidaw, Mandalay, Shwebo), upcountry (Myitkyina), Shan hills (Taunggyi, Lashio) and the Taninthayi coast (Mawlamyine, Dawei).  Yangon Circular Railway operates a 39-station commuter rail network that connects Yangon's

Rapid transit.

The Yangon Urban Mass Rapid Transit is a proposed

Buses and cars.

Yangon has a road network of all types (tar, concrete and dirt) in March 2011. Many of the roads are in poor condition and not wide enough to accommodate an increasing number of cars. The vast majority of Yangon residents cannot afford a car and rely on an extensive network of buses to get around. Over 300 public and private bus lines operate about 6,300 crowded buses around the city, carrying over 4.4 million passengers a day. All buses and 80% of

River.

Yangon's four main passenger jetties, all located on or near downtown waterfront, mainly serve local ferries across the river to Dala and Thanlyin, and regional ferries to the Irrawaddy delta. The 22-mile (35 km) Twante Canal was the

Demographics.

Yangon is the most populous city by far in Myanmar. According to the 2014 census, the city had a population of 5.16 million. The city's population grew sharply after 1948 as many people (mainly, the indigenous Burmese) from other parts of the country moved into the newly built satellite towns of North Okkalapa, South Okkalapa, and Thaketa in the 1950s and East Dagon, North Dagon and South Dagon in the 1990s. Immigrants have founded their regional associations (such as Mandalay Association, Mawlamyaing Association, etc.) in Yangon for networking purposes. The government's decision to move the nation's administrative capital to Naypyidaw has drained an unknown number of civil servants away from Yangon.  Yangon is the most ethnically diverse city in the country. While Indians formed the slight majority prior to World War II, today, the majority of the population is of indigenous Bamar (Burman) descent. Large communities of Indians/South Asian Burmese and the Chinese Burmese exist, especially in the traditional downtown neighborhoods. A large number of Rakhine and Karen also live in the city.  Burmese is the principal language of the city. English is by far the preferred second language of the educated class. In recent years, however, the prospect of overseas job opportunities has enticed some to study other languages: Mandarin Chinese is most popular, followed by Japanese, and French.

Religions.

The primary religions practised in Yangon are Buddhism, Christianity,

Media.

Yangon is the country's hub for the movie, music, advertising, newspaper, and book publishing industries. All media is heavily regulated by the military government. Television broadcasting is off-limits to the private sector. All media content must first be approved by the government's media censor board, Press Scrutiny and Registration Division.  Most television channels in the country are broadcast from Yangon. TV Myanmar and Myawaddy TV are the two main channels, providing Burmese-language news and entertainment programs. Other special interest channels are MWD-1 and MWD-2, MRTV-3, the English-language channel that targets overseas audiences via satellite and via Internet, MRTV-4 and Channel 7 (Yangon) are with a focus on non-formal education programs and movies, and Movie 5, a pay-TV channel specializing in broadcasting foreign movies.  Yangon has three radio stations. Myanmar Radio National Service is the national radio service and broadcasts mostly in Burmese (and in English during specific

Communication.

Common facilities taken for granted elsewhere are luxury prized items in Yangon and Burma. The price of a GSM mobile phone was about K1.1 million in August 2008. In 2007, the country of 55 million had only 775,000 phone lines (including 275,000 mobile phones), and 400,000 computers. Even in Yangon, which has the best infrastructure, the estimated telephone penetration rate was only 6%

Lifestyle.

Yangon's property market is the most expensive in the country and beyond the reach of most Yangonites. Most rent outside the centre and few can afford to rent such apartments. (In 2008, rents for a typical apartments in the centre and vicinity range between K70,000 and K150,000 and those for high end condos between K200,000 and K500,000.) Most men of all ages (and some women) spend their time at ubiquitous tea-shops, found in any corner or street of the city. Watching European football (mostly English Premier League with occasional La Liga, Serie A, Bundesliga) matches while sipping tea is a popular pastime among many Yangonites. The average person stays close to his or her residential neighborhood. The well-to-do tend to visit shopping malls and parks on weekends. Some leave the city on weekends for

Sports.

As the city has the best sporting facilities in the country, most national-level annual sporting tournaments such as track and field, football, volleyball, tennis and swimming are held in Yangon. The 40,000-seat Aung San Stadium and the 32,000-seat Thuwunna Stadium are the main venues for the highly popular annual State and Division football tournament. Until April 2009, the now-defunct Myanmar Premier League, consisted of 16 Yangon-based clubs, played all its matches in Yangon stadiums, and attracted little interest from the general public or commercial success despite the enormous popularity of football in Burma. Most Yangonites prefer watching European football on satellite TV. Teams such as Manchester United, Liverpool, Chelsea, Real Madrid, Barcelona, Bayern Munich, and Manchester City are among the favorite European teams among the Yangonites. It remains to be seen whether the

Economy.

Yangon is the country's main centre for trade, industry, real estate, media, entertainment and tourism. The city represents about one fifth of the national economy. According to official statistics for FY 2010–2011, the size of the economy of Yangon Region was 8.93 trillion kyats, or 23% of the national GDP. The city is Lower Burma's main trading hub for all kinds of merchandise – from basic foodstuffs to used cars although commerce continues to be hampered by the city's severely underdeveloped banking industry and communication infrastructure. Bayinnaung Market is the largest wholesale center in the country for rice, beans and pulses, and other agricultural commodities. Much of the country's legal imports and exports go through Thilawa Port, the largest and busiest port in Burma. There is also a great deal of informal trade, especially in street markets that exist alongside street platforms of Downtown Yangon's townships. However, on 17 June 2011, the YCDC announced that street vendors, who had previously been allowed to legally open shop at 3 pm, would be prohibited from selling on the streets, and permitted to sell only in their townships of residence, presumably to clean up the city's image. Since 1 December 2009, high-density polyethylene plastic bags have been banned by city authorities.  Manufacturing accounts for a sizeable share of employment. At least 14 light industrial zones ring Yangon, directly

Education.

Yangon educational facilities has a very high number of qualified teachers but the state spending on education is among the lowest of the world. Around 2007 estimate by the London-based International Institute for Strategic Studies puts the spending for education at 0.5% of the national budget. The disparity in educational opportunities and achievement between rich and poor schools is quite stark even within the city. With little or no state support forthcoming, schools have to rely on forced "donations" and various fees from parents for nearly everything – school maintenance to teachers' salaries, forcing many poor students to drop out.  While many students in poor districts fail to reach high school, a handful of Yangon high schools in wealthier districts such as Dagon 1, Sanchaung 2, Kamayut 2, Bahan 2, Latha 2, and TTC provide the majority of students admitted to

Health care.

The general state of health care in Yangon is poor. According to a 2007 estimate, the military government spends 0.4% of the national budget on health care, and 40% to 60% on defence. By the government's own figures, it spends 849 kyats (US$0.85) per person. Although health care is nominally free, in reality, patients have to pay for medicine and treatment, even in public clinics and hospitals. Public hospitals including the flagship Yangon General Hospital lack many of

International relations.

Yangon is a member of the Asian Network of Major Cities 21.

Twin towns – sister cities.

Yangon

Yangon ( Burmese: ရန်ကုန်; ; lit. 'End of Strife'), also known as Rangoon, is the capital of the Yangon Region and the largest city of Myanmar (also known as Burma). Yangon served as the capital of Myanmar until 2006, when the military government relocated the administrative functions to the purpose-built capital city of Naypyidaw in north central Myanmar. With over 5 million people, Yangon is Myanmar's most populous city and its most important commercial centre.

仰光(),原称大光(孟语:လဂုင် "la.gung";),为缅甸最大城市也是仰光省首府,原为缅甸首都(2005年11月6日迁至内比都),人口约735万(2014年统计),面积为312平方英里,位于仰光河河岸,伊洛瓦底江三角洲。仰光位于北纬16°48',东经96°9',而其时区是协调世界时加上六个半小时。主要出口有米、柚木、石油、棉花和各类金属矿藏等。与其他东南亚的大城市比较,仰光相对地不太繁荣。市内建筑迅速发展,大多数都是外资注入发展的(如中国、新加坡、日本,韩国等国)。市内的下城区及大仰光地区有很多连锁住宅和商业楼宇被重建或改建。现在仰光拥有东南亚最多的前殖民地建筑。在殖民地建筑内的政府部分(例如高等法院、市政厅、昂山将军市场和公立医院)也被列入重建项目。新城区和其他近郊的地区仍属贫穷地区。


Biography.

Early life.

He was born at Rufford House Farm, near Chesterfield, Derbyshire the son of James Bradbury Robinson, a maker of surgical dressings, and his wife, Jane Davenport.  Robinson went to school at the Chesterfield Grammar School and the private Fulneck School. He then studied Chemistry at the University of Manchester, graduating BSc in 1905. In 1907 he was awarded an 1851 Research Fellowship from the Royal Commission for the Exhibition of 1851 to continue his research at the University of Manchester.  He was appointed as the first Professor of Pure and Applied Organic Chemistry in the School of Chemistry at the University of Sydney in 1912. He was briefly at St Andrews University (1920–22) and then was offered the Chair of Organic Chemistry at Manchester University. In 1928 he moved from there to be a professor at University College London where he stayed only two years. He was the Waynflete Professor of Chemistry at Oxford University from 1930 and a Fellow of Magdalen College, Oxford.  "Robinson Close" in the Science Area at Oxford is named after him, as is the Robert Robinson Laboratory at the University of Liverpool, the Sir Robert Robinson Laboratory of Organic Chemistry at the University of Manchester and the Robinson and Cornforth Laboratories at the University of Sydney.  Robinson was a strong amateur chess player. He represented Oxford University in a friendly match with a team from Bletchley Park in December 1944; in which he lost his game to pioneering computer scientist I. J. Good. He was president of the British Chess Federation from 1950–53, and with Raymond Edwards he co-authored the book "The Art and Science of Chess" (Batsford, 1972).

Research.

His synthesis of tropinone, a precursor of cocaine, in 1917 was not only a big step in alkaloid chemistry but also showed that tandem reactions in a one-pot synthesis are capable of forming bicyclic molecules.  He invented the symbol for benzene having a circle in the middle whilst working at St Andrews University in 1923. He is known for inventing the use of the curly arrow to represent electron movement, and he is also known for discovering the molecular structures of morphine and penicillin. Robinson annulation has had application in the total synthesis of steroids.  In 1957 Robinson founded the journal "Tetrahedron" with fifty other editors for Pergamon Press.

Family.

He married twice. In 1912 he married Gertrude Maud Walsh. Following her death in 1954, in 1957 he married a widow, Mrs Stern Sylvia Hillstrom (née Hershey).

Sir Robert Robinson (13 September 1886 – 8 February 1975) was a British organic chemist and Nobel laureate recognised in 1947 for his research on plant dyestuffs (anthocyanins) and alkaloids. In 1947, he also received the Medal of Freedom with Silver Palm.

罗伯特·鲁宾逊爵士,OM,PRS、FRS(英语:Sir Robert Robinson,1886年-9月13日-1975年-2月8日),英国化学家,他于1947年赢得诺贝尔化学奖,原因是他对植物生物碱的研究。他从1930年到1954年在牛津大学担任化学系教授,同样时期担任Dyson Perrins实验室的头领,并且是皇家社会科学院的会员。


Name.

Its name was "man-eater" (from early Middle Persian مارتیا "mardya" "man" (as in human) and خوار "khowr-" "to eat"). The English term "manticore" was borrowed from Latin "mantichora", itself derived from the Greek rendering of the Persian name,, "martichora".  The Greeks also called it ἀνδροφάγος meaning "man-eater".

Origin.

The Manticore myth was of Persian origin. It passed into European folklore first through a remark by Ctesias, a Greek physician at the Persian court of King Artaxerxes II in the fourth century BC, in his book "Indica" ("India"), which circulated among Greek writers on natural history but has survived only in fragments, or references by those other writers.  The Aelian in his work, "Characteristics of Animals", had a complete section dedicated to Manticore: The Romanised Greek Pausanias, in his "Description of Greece", recalled strange animals he had seen at Rome and commented:  Pliny the Elder did not share Pausanias' skepticism. He followed Aristotle's natural history by including the "martichoras" – mistranscribed as "manticorus" in his copy of Aristotle – among his descriptions of animals in "Naturalis Historia" 8:30, c. 77 AD.  Later, in "The Life of Apollonius of Tyana", Greek writer Flavius Philostratus (c. 170–247) wrote:

Medieval and post-medieval appearances.

Pliny's book was widely enjoyed through the European Middle Ages, during which the manticore was sometimes described or illustrated in bestiaries. Through false etymology, it was sometimes assumed that the name was an amalgamation of "man" and "tiger". However, other sources regarded the "mantyger" as a different creature entirely. The mantyger was often depicted as having monkey-like feet, being apparently inspired by the baboon, and sometimes being represented with either tusks or short horns. There was further confusion as to whether the manticore should be identified with or distinguished from the "satyral" and the lampago.  Dante Alighieri, in his "Inferno", depicted the mythical creature Geryon as a manticore, following Pliny's description.  The manticore or mantyger first appeared in English heraldry in c. 1470, as a badge of William Hastings, 1st Baron Hastings; and in the 16th century it was used as a badge by Robert Radcliffe, 1st Earl of Sussex, and by Sir Anthony Babyngton.  Edward Topsell, in 1607, described the manticore as: Randle Holme drew on this description in 1688, when he described the manticore (which he regarded as distinct from the mantyger) as having: The heraldic manticore influenced some Mannerist representations of the sin of Fraud, conceived as a monstrous chimera with a beautiful woman's face – for example, in Bronzino's allegory, "Venus, Cupid, Folly and Time" (National Gallery, London), and more commonly in the decorative schemes called "grotteschi". From here it passed by way of Cesare Ripa's "Iconologia" into the seventeenth- and eighteenth-century French conception of a sphinx.  Gerald Brenan linked the manticore to the "mantequero", a monster feeding on human fat in Andalusian folklore.

The manticore (Early Middle Persian: "Merthykhuwar"; "Mardykhor") is a Persian legendary creature similar to the Egyptian sphinx that proliferated in western European medieval art as well. It has the head of a human, the body of a lion and a tail of venomous spines similar to porcupine quills, while other depictions have it with the tail of a scorpion. There are some accounts that the spines can be shot like arrows, thus making the manticore a lethal predator. It devours its prey whole, using its triple rows of teeth, leaves no traces of its victims (including bones) behind.

蝎狮(英语:Manticore),又被称为刺尾狮,是源自于波斯传说中的生物,却和埃及的斯芬克斯一样大量出现于欧洲中世纪的画作之中,外表为红色的狮身人面兽。主要栖息地为亚洲的森林中。或被称为Memecoleous。


Design.

Bioreactor design is a relatively complex engineering task, which is studied in the discipline of biochemical/bioprocess engineering. Under optimum conditions, the microorganisms or cells are able to perform their desired function with limited production of impurities. The environmental conditions inside the bioreactor, such as temperature, nutrient concentrations, pH, and dissolved gases (especially oxygen for aerobic fermentations) affect the growth and productivity of the organisms. The temperature of the fermentation medium is maintained by a cooling jacket, coils, or both. Particularly exothermic fermentations may require the use of external heat exchangers. Nutrients may be continuously added to the fermenter, as in a fed-batch system, or may be charged into the reactor at the beginning of fermentation. The pH of the medium is measured and adjusted with small amounts of acid or base, depending upon the fermentation. For aerobic (and some anaerobic) fermentations, reactant gases (especially oxygen) must be added to the fermentation. Since oxygen is relatively insoluble in water (the basis of nearly all fermentation media), air (or purified oxygen) must be added continuously. The action of the rising bubbles helps mix the fermentation medium and also "strips" out waste gases, such as carbon dioxide. In practice, bioreactors are often pressurized; this increases the solubility of oxygen in water. In an aerobic process, optimal oxygen transfer is sometimes the rate limiting step. Oxygen is poorly soluble in water—even less in warm fermentation broths—and is relatively scarce in air (20.95%). Oxygen transfer is usually helped by agitation, which is also needed to mix nutrients and to keep the fermentation homogeneous. Gas dispersing agitators are used to break up air bubbles and circulate them throughout the vessel.  "Fouling" can harm the overall efficiency of the bioreactor, especially the heat exchangers. To avoid it, the bioreactor must be easily cleaned. Interior surfaces are typically made of stainless steel for easy cleaning and sanitation. Typically bioreactors are cleaned between batches, or are designed to reduce fouling as much as possible when operated continuously. Heat transfer is an important part of bioreactor design; small vessels can be cooled with a cooling jacket, but larger vessels may require coils or an external heat exchanger.

Types.

Photobioreactor.

A photobioreactor (PBR) is a bioreactor which incorporates some type of light source (that may be natural sunlight or artificial illumination). Virtually any translucent container could be called a PBR, however the term is more commonly used to define a closed system, as opposed to an open storage tank or pond. Photobioreactors are used to grow small phototrophic organisms such as cyanobacteria, algae, or moss plants. These organisms use light through photosynthesis as their energy source and do not require sugars or lipids as energy source. Consequently, risk of contamination with other organisms like bacteria or fungi is lower in photobioreactors when compared to bioreactors for heterotroph organisms.

Sewage treatment.

Conventional sewage treatment utilises bioreactors to undertake the main purification processes. In some of these systems, a chemically inert medium with very high surface area is provided as a substrate for the growth of biological film. Separation of excess biological film takes place in settling tanks or cyclones. In other systems aerators supply oxygen to the sewage and biota to create activated sludge in which the biological component is freely mixed in the liquor in "flocs". In these processes, the liquid's Biochemical Oxygen Demand (BOD) is reduced sufficiently to render the contaminated water fit for reuse. The biosolids can be collected for further processing, or dried and used as fertilizer. An extremely simple version of a sewage bioreactor is a septic tank whereby the sewage is left in situ, with or without additional media to house bacteria. In this instance, the biosludge itself is the primary host for the bacteria.

Bioreactors for specialized tissues.

Many cells and tissues, especially mammalian ones, must have a surface or other structural support in order to grow, and agitated environments are often destructive to these cell types and tissues. Higher organisms, being auxotrophic, also require highly specialized growth media. This poses a challenge when the goal is to culture larger quantities of cells for therapeutic production purposes, and a significantly different design is needed compared to industrial bioreactors used for growing protein expression systems such as yeast and bacteria.  Many research groups have developed novel bioreactors for growing specialized tissues and cells on a structural scaffold, in attempt to recreate organ-like tissue structures "in-vitro". Among these include tissue bioreactors that can grow heart tissue, skeletal muscle tissue, ligaments, cancer tissue models, and others. Currently, scaling production of these specialized bioreactors for industrial use remains challenging and is an active area of research.  For more information on artificial tissue culture, see tissue engineering.

Modelling.

Mathematical models act as an important tool in various bio-reactor applications including wastewater treatment. These models are useful for planning efficient process control strategies and predicting the future plant performance. Moreover, these models are beneficial in education and research areas.  Bioreactors are generally used in those industries which are concerned with food, beverages and pharmaceuticals. The emergence of "Biochemical engineering" is of recent origin. Processing of biological materials using biological agents such as cells, enzymes or antibodies are the major pillars of biochemical engineering. Applications of biochemical engineering cover major fields of civilization such as agriculture, food and healthcare, resource recovery and fine chemicals.  Till now, the industries associated with biotechnology have been lagged behind other industries in implementing control over the process and optimization strategies. A main drawback in biotechnological process control is the problem to measure key physical and biochemical parameters.

Operational stages in a bio-process.

A bioprocess is composed mainly of three stages — upstream processing, bioreaction, and downstream processing — to convert raw material to finished product.  The raw material can be of biological or non-biological origin. It is first converted to more suitable form for processing. This is done in upstream processing step which involves chemical hydrolysis, preparation of liquid medium, separation of particulate, air purification and many other preparatory operations.  After upstream processing step, the resulting feed is transferred to one or more Bioreaction stages. The Biochemical reactors or bioreactors form the base of the Bioreaction step. This step mainly consists of three operations, namely, production of biomass, metabolite biosynthesis and biotransformation.  Finally, the material produced in the bioreactor must be further processed in the downstream section to convert it into more useful form. The downstream process mainly consists of physical separation operations which includes, solid liquid separation, adsorption, liquid-liquid extraction, distillation, drying etc.

Specifications.

A typical bioreactor consists of following parts:  Agitator – used for the mixing of the contents of the reactor which keeps the “cells” in the perfect homogenous condition for better transport of nutrients and oxygen to the desired product(s).  Baffle – used to break the vortex formation in the vessel, which is usually highly undesirable as it changes the center of gravity of the system and consumes additional power.  Sparger – In aerobic cultivation process, the purpose of the sparger is to supply adequate oxygen to the growing cells.  Jacket – The jacket provides the annular area for circulation of constant temperature of water which keeps the temperature of the bioreactor at a constant value.

Development of modelling equations for bioreactors.

Assumptions:

Total continuity equation.

Making overall mass balance, we get the following equation:  d("ρV)/dt = Fρ – Fρ = 0 (1)"  Equation(1) states that the reactor volume (V) is constant since dV/dt = 0.

Biomass continuity equation.

We know,  Flow rate of biomass into the reactor = Fx  Flow rate of biomass out of the reactor = Fx  Rate of generation of biomass by reaction = Vr  Rate of accumulation of biomass within the reactor = d(Vx)/dt  Now, apply general mass balance equation i.e.,  "Rate of Mass In – Rate of Mass Out + Rate of Generation = Accumulation"  d(Vx)/dt = Fx – Fx + Vr (2)  Where r is the rate of cell generation. Dividing both sides of the above equation by V, we obtain  dx/dt = (F/V)x – (F/V)x + r (3)  In the chemical reaction engineering, F/V is called space velocity(s) and V/F is called the residence time (s). But in biochemical engineering, F/V is known as Dilution rate (D). Accordingly, equation(3) yields:  dx/dt = Dx – Dx + r (4)  dx/dt = D(x – x) + r (5)

Substrate continuity equation.

For substrate balance,  Flow rate of substrate into the bioreactor = FS  Flow of the substrate out of the bioreactor = FS  Rate of generation of substrate by reaction = –Vr  Rate of accumulation of substrate within the reactor = d(VS)/dt  Now, apply general mass balance equation i.e.,  "Rate of Mass In – Rate of Mass Out + Rate of Generation = Accumulation"  d(VS)/dt = FS – FS – Vr (6)  rearranging above equation, we get  dS/dt = D(S –S ) – r (7)  where r is the rate of substrate consumption.

Biochemical reaction kinetics.

For the chemical reaction,  A ----> P  We can write  Where,  ( –r) = rate of disappearance of A  (r) = rate of formation of A  k = reaction rate constant  C = Concentration of reactant A  n = order of reaction with respect to component A  For first order reaction, n = 1 and accordingly,  –r = k C  The reaction kinetics involved in biochemical operations is comparatively difficult to obtain than the chemical reaction kinetics. In biochemical operations, the cell kinetics is used for the unstructured models where balanced growth condition is assumed.  The following equation is used to represent the net rate of cell mass growth:  r = "μx (10)"  "where μ" is the specific growth rate or specific growth rate coefficient(s). Here, "μ" is analogous to first order rate constant k but however, "μ" is not a constant.  In biochemical engineering, yield is defined as the ratio of mass or moles of product formed to the mass or moles of the reactants consumed. The yield (Y) of product (P) with respect to reactant A is defined as:  Y = (mass of P formed )/(mass of A consumed) (11)  In case of bioreactor,  Y = (mass of cells formed)/(mass of substrate consumed) (12)  Thus,  Y = r/ r  Or,  r = r/Y  Or,  r = "μx/"Y ( from 10) (13)

Final form of equation of modelling.

By substituting equations (10) & (13) in equations (5) & (7) respectively, we get,  dx/dt = D(x – x) + "μx" (14)  dS/dt = D(S – S) – ("μx/Y)" (15)  Since we have assumed that the feed stream does not contain any biomass i.e., x = 0, therefore, the bioreactor modelling equation finally gets the following form:  dx/dt = ("μ" – D)x (16)  dS/dt = D(S – S) – ("μx/Y)" "(from 15)"  Thus, Equations (15) and (16) are the basic equations which are used for the modelling of any bioreactor.

A bioreactor refers to any manufactured device or system that supports a biologically active environment. In one case, a bioreactor is a vessel in which a chemical process is carried out which involves organisms or biochemically active substances derived from such organisms. This process can either be aerobic or anaerobic. These bioreactors are commonly cylindrical, ranging in size from litres to cubic metres, and are often made of stainless steel.

生物反应器(英语:Bioreactor)是指任何提供生物化学反应的适当环境或工程设备。通常是指利用酶(由一个或一群酵素所推动)或生物体(如微生物)使装置具有模拟生物的功能,可在细胞外进行生化反应,在模拟的过程中既可进行有氧反应也能进行无氧反应。这些系统在酒类、组织工程、生化工程、医药生产、有机污染物降解...等应用上是相当重要的一个装置。


History.

Philosophical background.

The question of whether it is possible for machines to think has a long history, which is firmly entrenched in the distinction between dualist and materialist views of the mind. René Descartes prefigures aspects of the Turing test in his 1637 "Discourse on the Method" when he writes: Here Descartes notes that automata are capable of responding to human interactions but argues that such automata cannot respond appropriately to things said in their presence in the way that any human can. Descartes therefore prefigures the Turing test by defining the insufficiency of appropriate linguistic response as that which separates the human from the automaton. Descartes fails to consider the possibility that future automata might be able to overcome such insufficiency, and so does not propose the Turing test as such, even if he prefigures its conceptual framework and criterion.  Denis Diderot formulates in his "Pensées philosophiques" a Turing-test criterion:  "If they find

Alan Turing.

Researchers in the United Kingdom had been exploring "machine intelligence" for up to ten years prior to the founding of the field of artificial intelligence (AI) research in 1956. It was a common topic among the members of the Ratio Club, an informal group of British cybernetics and electronics researchers that included Alan Turing.  Turing, in particular, had been tackling the notion of machine intelligence since at least 1941 and one of the earliest-known mentions of "computer intelligence" was made by him in 1947. In Turing's report, "Intelligent Machinery", he investigated "the question of whether or not it is

ELIZA and PARRY.

In 1966, Joseph Weizenbaum created a program which appeared to pass the Turing test. The program, known as ELIZA, worked by examining a user's typed comments for keywords. If a keyword is found, a rule that transforms the user's comments is applied, and the resulting sentence is returned. If a keyword is not found, ELIZA responds either with a generic riposte or by repeating one of the earlier comments. In addition, Weizenbaum developed ELIZA to replicate the behaviour of a Rogerian psychotherapist, allowing ELIZA to be "free to assume the pose of knowing almost nothing of the real world." With these techniques, Weizenbaum's program was able to fool some people into believing that they were talking to a real person, with some subjects being "very hard to convince that ELIZA [...] is "not" human." Thus, ELIZA is claimed by some to be one

The Chinese room.

John Searle's 1980 paper "Minds, Brains, and Programs" proposed the "Chinese room" thought experiment and argued that the Turing test could not be used to determine if a machine can think. Searle noted that software (such as ELIZA) could pass the Turing test simply by manipulating symbols of which they had no understanding. Without understanding, they

Loebner Prize.

The Loebner Prize provides an annual platform for practical Turing tests with the first competition held in November 1991. It is underwritten by Hugh Loebner. The Cambridge Center for Behavioral Studies in Massachusetts, United States, organised the prizes up to and including the 2003 contest. As Loebner described it, one reason the competition was created is to advance the state of AI research, at least in part, because no one had taken steps to implement the Turing test despite 40 years of discussing it.  The first Loebner Prize competition in 1991 led to a renewed discussion of the viability of the Turing test and the value of pursuing it, in both the popular press and academia. The first contest was won by a mindless program with no identifiable intelligence that managed to fool naïve interrogators into making the wrong identification. This highlighted several of the shortcomings of the

Versions.

Saul Traiger argues that there are at least three primary versions of the Turing test, two of which are offered in "Computing Machinery and Intelligence" and one that he describes as the "Standard Interpretation". While there is some debate regarding whether the "Standard Interpretation" is that described by Turing or, instead, based on a misreading of his paper, these three versions are not regarded as equivalent, and their strengths and weaknesses are distinct.  Huma Shah points out that Turing himself was concerned with whether a machine could think and was providing a simple method to examine this: through human-machine question-answer sessions. Shah argues there is one imitation game which Turing described could be practicalised in two different ways: a) one-to-one interrogator-machine test, and b) simultaneous comparison of a machine with a human, both questioned in parallel by an interrogator. Since the Turing test is a test of indistinguishability in performance capacity, the verbal version generalises naturally to all of human performance capacity, verbal as well as nonverbal (robotic).

Imitation game.

Turing's original article describes a simple party game involving three players. Player A is a man, player B is a woman and player C (who plays the role of the interrogator) is of either sex. In the imitation game, player C is unable to see either player A or player B, and can communicate with them only through written notes. By asking questions of player A and player B, player C tries to determine which of the two is the man and which is the woman. Player A's role is to trick the interrogator into making the wrong decision, while player B attempts to assist the interrogator in making the right one.  Turing then asks:  What

Standard interpretation.

Common understanding has it that the purpose of the Turing test is not specifically to determine whether a computer is able to fool an interrogator into believing that it is a human, but rather whether a computer could "imitate" a human. While there is some dispute whether this interpretation was intended by Turing, Sterrett believes that it was and thus conflates the second version with this one, while

Imitation game vs. standard Turing test.

Controversy has arisen over which of the alternative formulations of the test Turing intended. Sterrett argues that two distinct tests can be extracted from his 1950 paper and that, "pace" Turing's remark, they are not equivalent. The test that employs the party game and compares frequencies of success is referred to as the "Original Imitation Game Test", whereas the test consisting of a human judge conversing with a human and a machine is referred to as the "Standard Turing Test", noting that Sterrett equates this with the "standard interpretation" rather than the second version of the imitation game. Sterrett agrees that the standard Turing test (STT) has the problems that its critics cite but feels that, in contrast, the original imitation game test (OIG test) so defined is immune to many of them, due to a crucial difference: Unlike the STT, it

Should the interrogator know about the computer?

A crucial piece of any laboratory test is that there should be a control. Turing never makes clear whether the interrogator in his tests is aware that one of the participants is a computer. However, if there were a machine that did have the potential to pass a Turing test, it would be safe to assume a double blind control would be necessary.  To return to the original imitation game, he states only that player A is to

Strengths.

Tractability and simplicity.

The power and appeal of the Turing test derives from its simplicity. The philosophy of mind, psychology, and modern neuroscience have been unable to provide definitions of "intelligence" and "thinking" that are sufficiently precise

Breadth of subject matter.

The format of the test allows the interrogator to give the machine a wide variety of intellectual tasks. Turing wrote that "the question and answer method seems to be suitable for introducing almost any one of the fields of human endeavour that we wish to include." John Haugeland adds that "understanding the words is not enough; you have to understand the "topic" as well."  To pass a well-designed Turing test, the machine must use natural language, reason, have knowledge

Emphasis on emotional and aesthetic intelligence.

As a Cambridge honours graduate in mathematics, Turing might have been expected to propose a test of computer intelligence requiring expert knowledge in some highly technical field, and thus anticipating a more recent approach to the subject. Instead, as already noted, the test which he described in his seminal 1950 paper requires the computer to be able to compete successfully in a common party game, and this by performing as well as the typical man in answering a series of questions so as to pretend convincingly to be the woman contestant.  Given the status of human sexual dimorphism as one of the most ancient of subjects, it is thus implicit in the above scenario that the questions to be answered will involve neither specialised factual

Weaknesses.

Turing did not explicitly state that the Turing test could be used as a measure of intelligence, or any other human quality. He wanted to provide a clear and understandable alternative to the word "think", which he could then use to reply to criticisms of the possibility of "thinking machines" and to suggest ways that research might move forward.  Nevertheless, the Turing test has been proposed as a measure of a machine's "ability to think" or its "intelligence". This proposal has received criticism from both philosophers and computer scientists. It assumes that an interrogator can determine if a machine is "thinking" by comparing its behaviour with human behaviour. Every element of this assumption has been questioned: the reliability of the interrogator's judgement, the value of comparing only behaviour and the value of comparing the machine with a human. Because of these and other considerations, some AI researchers have questioned the relevance of the test to their field.

Human intelligence vs. intelligence in general.

The Turing test does not directly test whether the computer behaves intelligently. It tests only whether the computer

Consciousness vs. the simulation of consciousness.

The Turing test is concerned strictly with how the subject "acts" – the external behaviour of the machine. In this regard, it takes a behaviourist or functionalist approach to the study of the mind. The example of ELIZA suggests that a machine passing the test may be able to simulate human conversational behaviour by following a simple (but large) list of mechanical

Naïveté of interrogators and the anthropomorphic fallacy.

In practice, the test's results can easily be dominated not by the computer's intelligence, but by the attitudes, skill, or naïveté of the questioner.  Turing does not specify the precise skills and knowledge required by the interrogator in his description of the test, but he did use the term "average interrogator": "[the] average interrogator would not have more than 70 per cent chance of making the right identification after five minutes of questioning".  Chatterbot programs such as ELIZA have repeatedly fooled unsuspecting people into believing that they are communicating with human beings. In these cases, the "interrogators" are not even aware of the possibility that they are interacting with computers.

Human misidentification.

One interesting feature of the Turing test is the frequency of the confederate effect, when the confederate (tested) humans are misidentified by the interrogators as machines. It has been suggested that what interrogators expect as human responses is not necessarily

Silence.

A critical aspect of the Turing test is that a machine must give itself away as being a machine by its utterances. An interrogator must then make the "right identification" by correctly identifying the machine as being just

Impracticality and irrelevance: the Turing test and AI research.

Mainstream AI researchers argue that trying to pass the Turing test is merely a distraction from more fruitful research. Indeed, the Turing test is not an active focus of much academic or commercial effort—as Stuart Russell and Peter Norvig write: "AI researchers have devoted little attention to passing the Turing test." There are several reasons.  First, there are easier ways to test their programs. Most current research in AI-related fields is aimed at modest and specific goals, such as automated scheduling, object recognition, or logistics. To test the intelligence of the programs that solve these problems, AI researchers simply give them the task directly. Russell and Norvig suggest an analogy with

Cognitive science.

Robert French (1990) makes the case that an interrogator can distinguish human and non-human interlocutors by posing questions that reveal the low-level (i.e.,

Variations.

Numerous other versions of the Turing test, including those expounded above, have been raised through the years.

Reverse Turing test and CAPTCHA.

A modification of the Turing test wherein the objective of one or more of the roles have been reversed between machines and humans is termed a reverse Turing test. An example is implied in the work of psychoanalyst Wilfred Bion, who was particularly fascinated by the "storm" that resulted from the encounter of one mind by another. In his 2000 book, among several other original points with regard to the Turing test, literary scholar Peter Swirski discussed in detail the idea of what he termed the Swirski test—essentially the reverse Turing test. He pointed out that it overcomes most if not all standard objections levelled at the standard version.  Carrying this idea forward, R. D. Hinshelwood described the mind as a "mind recognizing apparatus". The challenge would be for the computer to be able to determine if it were interacting with a human or another computer. This is

Subject matter expert Turing test.

Another variation is described as the subject-matter expert Turing test, where a machine's response cannot be distinguished

Total Turing test.

The "Total Turing test" variation of the Turing test, proposed by cognitive scientist Stevan Harnad, adds two further requirements

Electronic health records.

A letter published in "Communications of the ACM" describes the concept of generating a synthetic patient population and proposes a variation of Turing test to assess the difference between synthetic and real patients. The letter states: "In the EHR context, though a human physician can readily distinguish between synthetically generated

Minimum intelligent signal test.

The minimum intelligent signal test was proposed by Chris McKinstry as "the maximum abstraction of the Turing test", in which only binary responses (true/false or yes/no) are permitted, to focus only on the capacity for thought. It eliminates text

Hutter Prize.

The organisers of the Hutter Prize believe that compressing natural language text is a hard AI problem, equivalent to passing the

Other tests based on compression or Kolmogorov complexity.

A related approach to Hutter's prize which appeared much earlier in the late 1990s is the inclusion of compression problems in an extended Turing test. or by tests which are completely derived from Kolmogorov complexity. Other related tests in this line are

Ebert test.

The Turing test inspired the Ebert test proposed in 2011 by film critic Roger Ebert which

Predictions.

Turing predicted that machines would eventually be able to pass the test; in fact, he estimated that by the year 2000, machines with around 100 MB of storage would be able to fool 30% of human judges in a five-minute test, and that people would no longer consider the phrase "thinking machine" contradictory. (In practice, from 2009–2012, the Loebner Prize chatterbot contestants only managed to fool a judge once, and that was only due to the human contestant pretending to be a chatbot.) He further predicted that machine learning would be an important part of building powerful machines, a claim considered plausible by contemporary researchers in artificial intelligence.  In

Conferences.

Turing Colloquium.

1990 marked the fortieth anniversary of the first publication of Turing's "Computing Machinery and Intelligence" paper, and, saw renewed interest in the test. Two significant events occurred in that year: The first was the Turing Colloquium, which was held at the University of Sussex in April, and brought together academics and researchers from

2005 Colloquium on Conversational Systems.

In November 2005, the University of Surrey hosted an inaugural one-day meeting of artificial conversational entity developers, attended by winners

2008 AISB Symposium.

In parallel to the 2008 Loebner Prize held at the University of Reading, the Society for the Study of Artificial Intelligence and the Simulation of Behaviour (AISB), hosted a one-day symposium to discuss the Turing test, organised

The Alan Turing Year, and Turing100 in 2012.

Throughout 2012, a number of major events took place to celebrate Turing's life and scientific impact. The Turing100

The Turing test, developed by Alan Turing in 1950, is a test of a machine's ability to exhibit intelligent behaviour equivalent to, or indistinguishable from, that of a human. Turing proposed that a human evaluator would judge natural language conversations between a human and a machine designed to generate human-like responses. The evaluator would be aware that one of the two partners in conversation is a machine, and all participants would be separated from one another. The conversation would be limited to a text-only channel such as a computer keyboard and screen so the result would not depend on the machine's ability to render words as speech. If the evaluator cannot reliably tell the machine from the human, the machine is said to have passed the test. The test results do not depend on the machine's ability to give correct answers to questions, only how closely its answers resemble those a human would give.

图灵测试(英语:Turing test,又译图灵试验)是图灵于1950年提出的一个关于判断机器是否能够思考的著名思想实验,测试某机器是否能表现出与人等价或无法区分的智能。测试的谈话仅限于使用唯一的文本管道,例如计算机键盘和屏幕,这样的结果不依赖于计算机把单词转换为音频的能力。


Geography.

Laconia is bordered by Messenia to the west and Arcadia to the north and is surrounded by the Myrtoan Sea to the east and by the Laconian Gulf and the Mediterranean Sea to the south. It encompasses Cape Malea and Cape Tainaron and a large part of the Mani Peninsula. The Mani Peninsula is in the west region of Laconia. The islands of Kythira and Antikythera lie to the south, but they administratively belong to the Attica regional unit of islands. The island, Elafonisos, situated between the Laconian mainland and Kythira, is part of Laconia.  The Eurotas is the longest river in the prefecture. The valley of the Eurotas is predominantly an agricultural region that contains many citrus groves, olive groves, and pasture lands. It is the location of the largest orange production in the Peloponnese and probably in all of Greece. "Lakonia", a brand of orange juice, is based in Amykles.  The main mountain ranges are the Taygetus in the west and the Parnon in the northeast. Taygetus, known as Pentadaktylos ("five-fingers") throughout the Middle Ages, is west of Sparta and the Eurotas valley. It is the highest mountain in Laconia and the Peloponnese and is mostly covered with pine trees. Two roads join the Messenia and Laconia prefectures: one is a tortuous mountain pass through Taygetus and the other bypasses the mountain via the Mani district to the south.  The stalactite cave, Dirou, a major tourist attraction, is located south of Areopolis in the southwest of Laconia.

Climate.

Laconia has a Mediterranean climate with warm winters and hot summers. Snow is rare on the coast throughout the winter but is very common in the mountains.

History.

Ancient history.

Evidence of Neolithic settlement in southern Laconia has been found during excavations of the Alepotrypa cave site. In ancient Greece, this was the principal region of the Spartan state. For much of classical antiquity the Spartan sphere of influence expanded to Messenia, whose inhabitants (the Helots) were enslaved. Significant archaeological recovery exists at the Vaphio-tomb site in Laconia. Found here is advanced Bronze Age art as well as evidence of cultural associations with the contemporaneous Minoan culture on Crete. Laconia was at war with the Kingdom of Macedonia and saw several battles; at the end of the Mycenaean period, the population of Laconia sharply declined. From the early-2nd century BC until 395 AD, it was a part of the Roman Empire.

Medieval history.

In the medieval period, Laconia formed part of the Byzantine Empire. Following the Fourth Crusade, it was gradually conquered by the Frankish Principality of Achaea. In the 1260s, however, the Byzantines recovered Mystras and other fortresses in the region and managed to evict the Franks from Laconia, which became the nucleus of a new Byzantine province. By the mid-14th century, this evolved into the Despotate of Morea, held by the last Greek ruling dynasty, the Palaiologoi. With the fall of the Despotate to the Ottomans in 1460, Laconia was conquered as well.

Modern history.

With the exception of a 30-year interval of Venetian rule, Laconia remained under Ottoman control until the outbreak of the Greek War of Independence of 1821. Following independence, Sparta was selected as the capital of the modern prefecture, and its economy and agriculture expanded. With the incorporation of the British-ruled Ionian Islands into Greece in 1864, Elafonissos became part of the prefecture. After World War II and the Greek Civil War, its population began to somewhat decline, as people moved from the villages toward the larger cities of Greece and abroad.  In 1992, a devastating fire ruined the finest olive crops in the northern part of the prefecture, and affected the area of Sellasia along with Oinountas and its surrounding areas. Firefighters, helicopters and planes battled for days to put out the horrific fire.  The Mani portion along with Gytheio became famous in Greece for filming episodes of "Vendetta", broadcast on Mega Channel throughout Greece and abroad on Mega Cosmos.  In early 2006, flooding ruined olive and citrus crops as well as properties and villages along the Eurotas river. In the summer 2006, a terrible fire devastated a part of the Mani Peninsula, ruining forests, crops, and numerous villages.

Municipalities of Laconia.

The regional unit, Laconia, is subdivided into five municipalities. These are (number as in the map in the infobox):

Prefecture.

As a part of the 2011 Kallikratis government reform, regional unit Laconia was created out of the former prefecture Laconia (). The prefecture had the same territory as the present regional unit. At the same time, the municipalities were reorganised, according to the table below.  "Note:" Provinces no longer hold any legal status in Greece.

Population.

The main cities and towns of Laconia are (ranked by 2011 census population):

Laconia or Lakonia (,, ) is a historical and administrative region of Greece located on the southeastern part of the Peloponnese peninsula. Its administrative capital is Sparta. The word "laconic"—to speak in a blunt, concise way—is derived from the name of this region, a reference to the ancient Spartans who were renowned for their verbal austerity and blunt, often pithy remarks.

拉科尼亚(Λακωνία/Laconia)是希腊伯罗奔尼撒半岛东南部分的区域,也是拉科尼亚州的所在地。它的北面是阿卡迪亚,西面为麦西尼亚。直到前190年代,拉科尼亚一直是斯巴达的核心地区,其中斯巴达是最重要的城市。直到今天,斯巴达仍是拉科尼亚州的州府。面积3636平方公里,人口89,138人(2011年)。


Signs and symptoms.

Signs and symptoms vary depending on the type of cataract, though considerable overlap occurs. People with nuclear sclerotic or brunescent cataracts often notice a reduction of vision. Nuclear cataracts typically cause greater impairment of distance vision than of near vision. Those with posterior subcapsular cataracts usually complain of glare as their major symptom.  The severity of cataract formation, assuming no other eye disease is present, is judged primarily by a visual acuity test. Other symptoms include frequent changes of glasses and colored halos due to hydration of lens.  Congenital cataracts can result in amblyopia if not treated in a timely manner.

Causes.

Age.

Age is the most common cause. Lens proteins denature and degrade over time, and this process is accelerated by diseases such as diabetes mellitus and hypertension. Environmental factors, including toxins and radiation, including ultraviolet light, have cumulative effects, which are worsened by the loss of protective and restorative mechanisms due to alterations in gene expression and chemical processes within the eye.

Trauma.

Blunt trauma causes swelling, thickening, and whitening of the lens fibers. While the swelling normally resolves with time, the white color may remain. In severe blunt trauma, or in injuries that penetrate the eye, the capsule in which the lens sits can be damaged. This damage allows fluid from other parts of the eye to rapidly enter the lens leading to swelling and then whitening, obstructing light from reaching the retina at the back of the eye. Cataracts may develop in 0.7 to 8.0% of cases following electrical injuries. Blunt trauma can also result in star- (stellate) or petal-shaped cataracts.

Radiation.

Cataracts can arise as an effect of exposure to various types of radiation. X-rays, one form of ionizing radiation, may damage the DNA of lens cells. Ultraviolet light, specifically UVB, has also been shown to cause cataracts, and some evidence indicates sunglasses worn at an early age can slow its development in later life. Microwaves, a type of nonionizing radiation, may cause harm by denaturing protective enzymes (e.g., glutathione peroxidase), by oxidizing protein thiol groups (causing protein aggregation), or by damaging lens cells via thermoelastic expansion. The protein coagulation caused by electric and heat injuries whitens the lens. This same process is what makes the clear albumen of an egg become white and opaque during cooking.

Genetics.

The genetic component is strong in the development of cataracts, most commonly through mechanisms that protect and maintain the lens. The presence of cataracts in childhood or early life can occasionally be due to a particular syndrome. Examples of chromosome abnormalities associated with cataracts include 1q21.1 deletion syndrome, cri-du-chat syndrome, Down syndrome, Patau's syndrome, trisomy 18 (Edward's syndrome), and Turner's syndrome, and in the case of neurofibromatosis type 2, juvenile cataract on one or both sides may be noted. Examples of single-gene disorder include Alport's syndrome, Conradi's syndrome, cerebrotendineous xanthomatosis, myotonic dystrophy, and oculocerebrorenal syndrome or Lowe syndrome.

Skin diseases.

The skin and the lens have the same embryological origin and so can be affected by similar diseases. Those with atopic dermatitis and eczema occasionally develop shield ulcer cataracts. Ichthyosis is an autosomal recessive disorder associated with cuneiform cataracts and nuclear sclerosis. Basal-cell nevus and pemphigus have similar associations.

Smoking and alcohol.

Cigarette smoking has been shown to double the rate of nuclear sclerotic cataracts and triple the rate of posterior subcapsular cataracts. Evidence is conflicting over the effect of alcohol. Some surveys have shown a link, but others which followed people over longer terms have not.

Inadequate vitamin C.

Low vitamin C intake and serum levels have been associated with greater cataract rates. However, use of supplements of vitamin C has not demonstrated benefit.

Medications.

Some medications, such as systemic, topical, or inhaled corticosteroids, may increase the risk of cataract development. Corticosteroids most commonly cause posterior subcapsular cataracts. People with schizophrenia often have risk factors for lens opacities (such as diabetes, hypertension, and poor nutrition) but antipsychotic medications are unlikely to contribute to cataract formation. Miotics and triparanol may increase the risk.

Post-operative.

Nearly every person who undergoes a vitrectomy—without ever having had cataract surgery—will experience progression of nuclear sclerosis after the operation. This may be because the native vitreous humor is different from the solutions used to replace the vitreous (vitreous substitutes), such as BSS Plus. This may also be because the native vitreous humour contains ascorbic acid which helps neutralize oxidative damage to the lens and because conventional vitreous substitutes do not contain ascorbic acid. As such, for phakic patients requiring a vitrectomy it is becoming increasingly common for ophthalmologists to offer the vitrectomy combined with prophylactic cataract surgery to prevent cataract formation.

Diagnosis.

Classification.

Cataracts may be partial or complete, stationary or progressive, or hard or soft. The main types of age-related cataracts are nuclear sclerosis, cortical, and posterior subcapsular.  Nuclear sclerosis is the most common type of cataract, and involves the central or 'nuclear' part of the lens. This eventually becomes hard, or'sclerotic', due to condensation on the lens nucleus and the deposition of brown pigment within the lens. In its advanced stages it is called a brunescent cataract. In early stages, an increase in sclerosis may cause an increase in refractive index of the lens. This causes a myopic shift (lenticular shift) that decreases hyperopia and enables presbyopic patients to see at near without reading glasses. This is only tempororary and is called second sight.  Cortical cataracts are due to the lens cortex (outer layer) becoming opaque. They occur when changes in the fluid contained in the periphery of the lens causes fissuring. When these cataracts are viewed through an ophthalmoscope, or other magnification system, the appearance is similar to white spokes of a wheel. Symptoms often include problems with glare and light scatter at night.  Posterior subcapsular cataracts are cloudy at the back of the lens adjacent to the capsule (or bag) in which the lens sits. Because light becomes more focused toward the back of the lens, they can cause disproportionate symptoms for their size.  An immature cataract has some transparent protein, but with a mature cataract, all the lens protein is opaque. In a hypermature or Morgagnian cataract, the lens proteins have become liquid. Congenital cataract, which may be detected in adulthood, has a different classification and includes lamellar, polar, and sutural cataracts.  Cataracts can be classified by using the lens opacities classification system LOCS III. In this system, cataracts are classified based on type as nuclear, cortical, or posterior. The cataracts are further classified based on severity on a scale from 1 to 5. The LOCS III system is highly reproducible.

Prevention.

Risk factors such as UVB exposure and smoking can be addressed. Although no means of preventing cataracts has been scientifically proven, wearing sunglasses that counteract ultraviolet light may slow their development. While adequate intake of antioxidants (such as vitamins A, C, and E) has been thought to protect against the risk of cataracts, clinical trials have shown no benefit from supplements; though evidence is mixed, but weakly positive, for a potential protective effect of the nutrients lutein and zeaxanthin. Statin use is somewhat associated with a lower risk of nuclear sclerotic cataracts.

Treatment.

Surgical.

The appropriateness of surgery depends on a person's particular functional and visual needs and other risk factors. Cataract removal can be performed at any stage and no longer requires ripening of the lens. Surgery is usually "outpatient" and usually performed using local anesthesia. About 9 of 10 patients can achieve a corrected vision of 20/40 or better after surgery.  Several recent evaluations found that cataract surgery can meet expectations only when significant functional impairment due to cataracts exists before surgery. Visual function estimates such as VF-14 have been found to give more realistic estimates than visual acuity testing alone. In some developed countries, a trend to overuse cataract surgery has been noted, which may lead to disappointing results.  Phacoemulsification is the most widely used cataract surgery in the developed world. This procedure uses ultrasonic energy to emulsify the cataract lens. Phacoemulsification typically comprises six steps:  A Cochrane review found little to no difference in visual acuity as a function of the size of incisions made for phacoemulsification in the range from ≤ 1.5 mm to 3.0 mm.  Extracapsular cataract extraction (ECCE) consists of removing the lens manually, but leaving the majority of the capsule intact. The lens is expressed through a 10- to 12-mm incision which is closed with sutures at the end of surgery. ECCE is less frequently performed than phacoemulsification, but can be useful when dealing with very hard cataracts or other situations where emulsification is problematic. Manual small incision cataract surgery (MSICS) has evolved from ECCE. In MSICS, the lens is removed through a self-sealing scleral tunnel wound in the sclera which, ideally, is watertight and does not require suturing. Although "small", the incision is still markedly larger than the portal in phacoemulsion. This surgery is increasingly popular in the developing world where access to phacoemulsification is still limited.  Intracapsular cataract extraction (ICCE) is rarely performed. The lens and surrounding capsule are removed in one piece through a large incision while pressure is applied to the vitreous membrane. The surgery has a high rate of complications.

Prognosis.

Postoperative care.

The postoperative recovery period (after removing the cataract) is usually short. The patient is usually ambulatory on the day of surgery, but is advised to move cautiously and avoid straining or heavy lifting for about a month. The eye is usually patched on the day of surgery and use of an eye shield at night is often suggested for several days after surgery.  In all types of surgery, the cataractous lens is removed and replaced with an artificial lens, known as an intraocular lens, which stays in the eye permanently. Intraocular lenses are usually monofocal, correcting for either distance or near vision. Multifocal lenses may be implanted to improve near and distance vision simultaneously, but these lenses may increase the chance of unsatisfactory vision.

Complications.

Serious complications of cataract surgery include retinal detachment and endophthalmitis. In both cases, patients notice a sudden decrease in vision. In endophthalmitis, patients often describe pain. Retinal detachment frequently presents with unilateral visual field defects, blurring of vision, flashes of light, or floating spots.  The risk of retinal detachment was estimated as about 0.4% within 5.5 years, corresponding to a 2.3-fold risk increase compared to naturally expected incidence, with older studies reporting a substantially higher risk. The incidence is increasing over time in a somewhat linear manner, and the risk increase lasts for at least 20 years after the procedure. Particular risk factors are younger age, male sex, longer axial length, and complications during surgery. In the highest risk group of patients, the incidence of pseudophakic retinal detachment may be as high as 20%.  The risk of endophthalmitis occurring after surgery is less than one in 1000.  Corneal edema and cystoid macular edema are less serious but more common, and occur because of persistent swelling at the front of the eye in corneal edema or back of the eye in cystoid macular edema. They are normally the result of excessive inflammation following surgery, and in both cases, patients may notice blurred, foggy vision. They normally improve with time and with application of anti-inflammatory drops. The risk of either occurring is around one in 100. It is unclear whether NSAIDs or corticosteroids are superior at reducing postoperative inflammation.  Posterior capsular opacification, also known as after-cataract, is a condition in which months or years after successful cataract surgery, vision deteriorates or problems with glare and light scattering recur, usually due to thickening of the back or posterior capsule surrounding the implanted lens, so-called 'posterior lens capsule opacification'. Growth of natural lens cells remaining after the natural lens was removed may be the cause, and the younger the patient, the greater the chance of this occurring. Management involves cutting a small, circular area in the posterior capsule with targeted beams of energy from a laser, called capsulotomy, after the type of laser used. The laser can be aimed very accurately, and the small part of the capsule which is cut falls harmlessly to the bottom of the inside of the eye. This procedure leaves sufficient capsule to hold the lens in place, but removes enough to allow light to pass directly through to the retina. Serious side effects are rare. Posterior capsular opacification is common and occurs following up to one in four operations, but these rates are decreasing following the introduction of modern intraocular lenses together with a better understanding of the causes.  Vitreous touch syndrome is a possible complication of intracapsular cataract extraction.

Epidemiology.

Age-related cataracts are responsible for 51% of world blindness, about 20 million people. Globally, cataracts cause moderate to severe disability in 53.8 million (2004), 52.2 million of whom are in low and middle income countries.  In many countries, surgical services are inadequate, and cataracts remain the leading cause of blindness. Even where surgical services are available, low vision associated with cataracts may still be prevalent as a result of long waits for, and barriers to, surgery, such as cost, lack of information and transportation problems.  In the United States, age-related lens changes have been reported in 42% between the ages of 52 and 64, 60% between the ages 65 and 74, and 91% between the ages of 75 and 85. Cataracts affect nearly 22 million Americans age 40 and older. By age 80, more than half of all Americans have cataracts. Direct medical costs for cataract treatment are estimated at $6.8 billion annually.  In the eastern Mediterranean region, cataracts are responsible for over 51% of blindness. Access to eye care in many countries in this region is limited. Childhood-related cataracts are responsible for 5–20% of world childhood blindness.

History.

Cataract surgery was first described by the Indian physician, Suśruta (about 5th century BCE) in his manuscript Sushruta Samhita in ancient India. Most of the methods mentioned focus on hygiene. Follow-up treatments include bandaging of the eye and covering the eye with warm butter. References to cataracts and their treatment in Ancient Rome are also found in 29 AD in "De Medicinae", the work of the Latin encyclopedist Aulus Cornelius Celsus. Archaeological evidence of eye surgery in the Roman era also exists.  Galen of Pergamon (ca. 2nd century CE), a prominent Greek physician, surgeon and philosopher, performed an operation similar to modern cataract surgery. Using a needle-shaped instrument, Galen attempted to remove the cataract-affected lens of the eye.  Muslim ophthalmologist Ammar Al-Mawsili, in his "Choice of Eye Diseases", written "circa" 1000, wrote of his invention of a syringe and the technique of cataract extraction while experimenting with it on a patient.

Etymology.

"Cataract" is derived from the Latin ', meaning "waterfall", and from the Ancient Greek ('), "down-rushing", from καταράσσω ("katarassō") meaning "to dash down" (from "kata"-, "down"; "arassein", "to strike, dash"). As rapidly running water turns white, so the term may have been used metaphorically to describe the similar appearance of mature ocular opacities. In Latin, "cataracta" had the alternative meaning "portcullis" and the name possibly passed through French to form the English meaning "eye disease" (early 15th century), on the notion of "obstruction". Early Persian physicians called the term "nazul-i-ah", or "descent of the water"—vulgarised into waterfall disease or cataract—believing such blindness to be caused by an outpouring of corrupt humour into the eye.

Research.

N-Acetylcarnosine drops have been investigated as a medical treatment for cataracts. The drops are believed to work by reducing oxidation and glycation damage in the lens, particularly reducing crystallin crosslinking. Some benefit has been shown in small manufacturer-sponsored randomized controlled trials but further independent corroboration is still required.  Femtosecond laser mode-locking, used during cataract surgery, was originally used to cut accurate and predictable flaps in LASIK surgery, and has been introduced to cataract surgery. The incision at the junction of the sclera and cornea and the hole in capsule during capsulorhexis, traditionally made with a handheld blade, needle, and forceps, are dependent on skill and experience of the surgeon. Sophisticated three-dimensional images of the eyes can be used to guide lasers to make these incisions. can also then break up the cataract as in phacoemulsification.  Stem cells have been used in a clinical trial for lens regeneration in twelve children under the age of two with cataracts present at birth. The children were followed for six months, so it is unknown what the long-term results will be, and it is unknown if this procedure would work in adults.

A cataract is an opacification of the lens of the eye which leads to a decrease in vision. Cataracts often develop slowly and can affect one or both eyes. Symptoms may include faded colors, blurry or double vision, halos around light, trouble with bright lights, and trouble seeing at night. This may result in trouble driving, reading, or recognizing faces. Poor vision caused by cataracts may also result in an increased risk of falling and depression. Cataracts cause half of all cases of blindness and 33% of visual impairment worldwide. Cataracts are most commonly due to aging but may also occur due to trauma or radiation exposure, be present from birth, or occur following eye surgery for other problems. Risk factors include diabetes, smoking tobacco, prolonged exposure to sunlight, and alcohol. The underlying mechanism involves accumulation of clumps of protein or yellow-brown pigment in the lens that reduces transmission of light to the retina at the back of the eye. Diagnosis is by an eye examination. Prevention includes wearing sunglasses, a wide brimmed hat, eating leafy vegetables and fruits, and avoiding smoking. Early on the symptoms may be improved with glasses. If this does not help, surgery to remove the cloudy lens and replace it with an artificial lens is the only effective treatment. Cataract surgery is not readily available in many countries, and surgery is needed only if the cataracts are causing problems and generally results in an improved quality of life. About 20 million people are blind due to cataracts. It is the cause of approximately 5% of blindness in the United States and nearly 60% of blindness in parts of Africa and South America. Blindness from cataracts occurs in about 10 to 40 per 100,000 children in the developing world, and 1 to 4 per 100,000 children in the developed world. Cataracts become more common with age. In the United States, cataracts occur in 68% of those over the age of 80 years. Additionally they are more common in women and White people.

白内障()是因为眼睛水晶体混浊而造成视力缺损的疾病,可能侵犯单眼或双眼。症状包含彩度降低、视线模糊、光源产生光晕、无法适应亮光,以及黑暗环境下视觉障碍。白内障可能导致驾驶困难、阅读障碍,以及识人能力减低。视觉减退也会导致跌倒和忧郁的风险。该病为全球半数眼盲及33%视力受损病例的原因。 白内障最常见的原因为老化,其他原因则包含创伤、辐射线暴露、先天性、眼睛手术后的并发症,或是其他原因。风险因子包含糖尿病、吸烟、阳光暴露过久,以及酒精。造成白内障的原因为,沉积在水晶体的蛋白质团块或黄棕色色素导致水晶体的透明度减低,进而使视网膜能传感到的光线下降。诊断方式为视力测试。 预防方法包含配戴太阳眼镜及禁烟。症状初期可能可以借由配戴眼镜改善。若效果不佳,唯一有效的疗法为白内障手术,移除混浊的水晶体并换上人工水晶体,不过只有白内障影响到日常生活时才需要进行手术,一般而言,手术会提升生活品质。白内障手术在许多国家仍无法实施,尤其是女性、乡村居民,以及文盲等患者,特别少进行手术。 约全球约2000万人因白内障而眼盲,该病占美国盲眼人口病因的5%,在非洲及南美则接近六成。在发展中国家,儿童因白内障导致眼盲的发生率约为每十万人中10-40人,已开发国家则为每十万人1-4人。白内障的比例会随年龄提高,在美国80岁以上的老人有半数以上罹患此病。


History.

3sat was established to broadcast cultural programmes, originally by satellite. The network was founded as a cooperative network by Germany's ZDF, Austria's ORF and Switzerland's SRG SSR (formerly SRG SSR idée suisse). 3sat began broadcasting on 1 December 1984. ZDF leads the cooperative, though decisions are reached through consensus of the cooperative's partners.  In 1990, DFF, television broadcaster of the German Democratic Republic became a cooperative member of 3sat, and a name change to 4sat was considered. Eventually it was decided to keep the original 3sat name. DFF's membership of 3sat was dissolved on 31 December 1991, as DFF itself ceased to exist, in accordance with Germany's Unification Treaty.  On 1 December 1993, ARD joined 3sat as a cooperative member. This followed ARD's creation of its own satellite channel, Eins Plus. 3sat is available on the European Astra satellites at 19.2° east, on cable television, and in Austria and Germany on digital terrestrial television.  In 2003, 3sat was available in 40 million households in Germany, Austria and Switzerland, and 85.5 million households across Europe. Since June 2003 3sat has been using a new on-air look and logo. The logo has a red rectangle surrounding a number three.  In 2005, 3sat and n-tv were criticised for broadcasting TV shows which were funded by relief organizations such as "World Vision Deutschland" and Christoffel Blindenmission.  In 2008, the programs "nano" and "Kulturzeit" received a new on-air look and a new studios. At the "Eyes & Ears of Europe Awards", the design of "Kulturzeit"'s studio was awarded first prize in the category "Best Study Design" at Medientage München in 2008.  In 2009 3sat had a market share of 1.1% in Germany, 1.9% in Austria and 1.2% in Switzerland.  As a result of ZDF's spending for the then-new ZDFkultur, 2011 saw the end of many long-term 3sat broadcasts such as "3satbörse", "Foyer", the computer and internet magazine "neues", the animal show "Arche Noah", the legal magazine "Recht brisant", "Vivo" and others.  On 1 April 2017, the "Direktion Europäische Satellitenprogramme", which was responsible for 3sat and Arte programs, was dissolved. It was replaced by joint editorial teams with the other ZDF channels.

3sat is a free-to-air German-language public service television channel. It is a generalist channel with a cultural focus and is jointly operated by public broadcasters from Germany (ZDF, ARD), Austria (ORF) and Switzerland (SRG SSR). The coordinating broadcaster is ZDF, at whose Mainz facility the broadcasting centre with studios for in-house productions is located.

3sat是一家总部位于德国美因茨的公共电视台,由德国公共广播联盟(ARD)、德国电视二台(ZDF)、奥地利广播集团(ORF)以及瑞士广播电视集团(SRG SSR)共同运营,面向德国、奥地利、瑞士等德语使用者较多的国家播出。