Terminology.

"Metro" is the most common term for underground rapid transit systems used by non-native English speakers. Rapid transit systems may be named after the medium by which passengers travel in busy central business districts; the use of tunnels inspires names such as "subway", "underground", "Untergrundbahn (U-Bahn)" in German, or the "Tunnelbana (T-bana)" in Swedish; the use of viaducts inspires names such as "elevated" ("L" or "el"), "skytrain", "overhead", "overground" or "Hochbahn" in German. One of these terms may apply to an entire system, even if a large part of the network (for example, in outer suburbs) runs at ground level.  In most of Britain, a "subway" is a pedestrian underpass; the terms "Underground" and "Tube" are used for the London Underground, and the North East England Tyne and Wear Metro, mostly overground, is known as the "Metro". In Scotland, however, the Glasgow Subway underground rapid transit system is known as the "Subway". In most of North America, underground mass transit systems are primarily known as "subways". The term "metro" is a shortened reference to a metropolitan area. Chicago's commuter rail system that serves the entire metropolitan area is called "Metra", while its rapid transit system that serves the city is called the "L". Rapid transit systems such as the Washington Metro, Los Angeles Metro Rail, the Miami Metrorail, and the Montreal Metro are generally called the "Metro". However the Boston subway system is known locally as "The T". In most of Southeast Asia, rapid transit systems are primarily known as "MRT" (Mass Rapid Transit) or "MTR" (Mass Transit Railway).

History.

The opening of London's steam-hauled Metropolitan Railway in 1863 marked the beginning of rapid transit. Initial experiences with steam engines, despite ventilation, were unpleasant. Experiments with pneumatic railways failed in their extended adoption by cities. Electric traction was more efficient, faster and cleaner than steam and the natural choice for trains running in tunnels and proved superior for elevated services.  In 1890 the City & South London Railway was the first electric-traction rapid transit railway, which was also fully underground. Prior to opening the line was to be called the "City and South London Subway", thus introducing the term Subway into railway terminology. Both railways, alongside others, were eventually merged into London Underground. The 1893 Liverpool Overhead Railway was designed to use electric traction from the outset.  The technology quickly spread to other cities in Europe, the United States, Argentina, and Canada, with some railways being converted from steam and others being designed to be electric from the outset. Budapest, Chicago, Glasgow and New York all converted or purpose-designed and built electric rail services.  Advancements in technology have allowed new automated services. Hybrid solutions have also evolved, such as tram-train and premetro, which incorporate some of the features of rapid transit systems. In response to cost, engineering considerations and topological challenges some cities have opted to construct tram systems, particularly those in Australia, where density in cities was low and suburbs tended to spread out. Since the 1970s, the viability of underground train systems in Australian cities, particularly Sydney and Melbourne, has been reconsidered and proposed as a solution to over-capacity. The first rapid transit line in Australia was opened in Sydney in 2019, which will feed into a larger network known as the Sydney Metro upon completion of a second line in 2024.  Since the 1960s many new systems were introduced in Europe, Asia and Latin America. In the 21st century, most new expansions and systems are located in Asia, with China becoming the world's leader in metro expansion operating some of the largest and busiest systems while possessing almost 60 cities operating, constructing or planning a rapid transit system.

Operation.

Rapid transit is used in cities, agglomerations, and metropolitan areas to transport large numbers of people often short distances at high frequency. The extent of the rapid transit system varies greatly between cities, with several transport strategies.  Some systems may extend only to the limits of the inner city, or to its inner ring of suburbs with trains making frequent station stops. The outer suburbs may then be reached by a separate commuter rail network where more widely spaced stations allow higher speeds. In some cases the differences between urban rapid transit and suburban systems are not clear.  Rapid transit systems may be supplemented by other systems such as trolleybuses, regular buses, trams, or commuter rail. This combination of transit modes serves to offset certain limitations of rapid transit such as limited stops and long walking distances between outside access points. Bus or tram feeder systems transport people to rapid transit stops.

Lines.

Each rapid transit system consists of one or more "lines", or circuits. Each line is serviced by at least one specific route with trains stopping at all or some of the line's stations. Most systems operate several routes, and distinguish them by colors, names, numbering, or a combination thereof. Some lines may share track with each other for a portion of their route or operate solely on their own right-of-way. Often a line running through the city center forks into two or more branches in the suburbs, allowing a higher service frequency in the center. This arrangement is used by many systems, such as the Copenhagen Metro, the Milan Metro, the Oslo Metro and the New York City Subway.  Alternatively, there may be a single central terminal (often shared with the central railway station), or multiple interchange stations between lines in the city center, for instance in the Prague Metro. The London Underground and Paris Métro are densely built systems with a matrix of crisscrossing lines throughout the cities. The Chicago 'L' has most of its lines converging on The Loop, the main business, financial, and cultural area. Some systems have a circular line around the city center connecting to radially arranged outward lines, such as the Moscow Metro's Koltsevaya Line and Beijing Subway's Line 10.  The capacity of a line is obtained by multiplying the car capacity, the train length, and the service frequency. Heavy rapid transit trains might have six to twelve cars, while lighter systems may use four or fewer. Cars have a capacity of 100 to 150 passengers, varying with the seated to standing ratio—more standing gives higher capacity. The minimum time interval between trains is shorter for rapid transit than for mainline railways owing to the use of Communications based train control: the minimum headway can reach 90 seconds, but many systems typically use 120 seconds to allow for recovery from delays. Typical capacity lines allow 1,200 people per train, giving 36,000 people per hour. The highest attained capacity is 80,000 people per hour by the MTR Corporation in Hong Kong.

Network topologies.

Rapid transit topologies are determined by a large number of factors, including geographical barriers, existing or expected travel patterns, construction costs, politics, and historical constraints. A transit system is expected to serve an "area" of land with a set of "lines", which consist of shapes summarized as "I", "U", "S", and "O" shapes or loops. Geographical barriers may cause chokepoints where transit lines must converge (for example, to cross a body of water), which are potential congestion sites but also offer an opportunity for transfers between lines. Ring lines provide good coverage, connect between the radial lines and serve tangential trips that would otherwise need to cross the typically congested core of the network. A rough grid pattern can offer a wide variety of routes while still maintaining reasonable speed and frequency of service. A study of the 15 world largest subway systems suggested a universal shape composed of a dense core with branches radiating from it.

Passenger information.

Rapid transit operators have often built up strong brands, often focused on easy recognition—to allow quick identification even in the vast array of signage found in large cities—combined with the desire to communicate speed, safety, and authority. In many cities, there is a single corporate image for the entire transit authority, but the rapid transit uses its own logo that fits into the profile.  A transit map is a topological map or schematic diagram used to show the routes and stations in a public transport system. The main components are color-coded lines to indicate each line or service, with named icons to indicate stations. Maps may show only rapid transit or also include other modes of public transport. Transit maps can be found in transit vehicles, on platforms, elsewhere in stations, and in printed timetables. Maps help users understand the interconnections between different parts of the system; for example, they show the interchange stations where passengers can transfer between lines. Unlike conventional maps, transit maps are usually not geographically accurate, but emphasize the topological connections among the different stations. The graphic presentation may use straight lines and fixed angles, and often a fixed minimum distance between stations, to simplify the display of the transit network. Often this has the effect of compressing the distance between stations in the outer area of the system, and expanding distances between those close to the center.  Some systems assign unique alphanumeric codes to each of their stations to help commuters identify them, which briefly encodes information about the line it is on, and its position on the line. For example, on the Singapore MRT, Changi Airport MRT station has the alphanumeric code CG2, indicating its position as the 2nd station on the Changi Airport branch of the East West Line. Interchange stations would have at least two codes, for example, Raffles Place MRT station has two codes, NS26 and EW14, the 26th station on the North South Line and the 14th station on the East West Line. Seoul Metro is another example that utilizes a code for its stations. But unlike that of Singapore's MRT, it's mostly numbers. Based on the line number, for example Sinyongsan station, coded as station 429. As it is on Line 4, the first number of the station code is 4. The last 2 numbers will be the station number on that line. Interchange stations can have multiple codes. Like City Hall station in Seoul which is served by Line 1 and Line2. It has a code of 132 and 201 respectively. The Line 2 is a circle line and the first stop is City Hall, therefore, City Hall has the station code of 201. For lines without a number like Bundang line it will have an alphanumeric code. Lines without a number that are operated by KORAIL will start with the letter 'K'.  With widespread use of the Internet and cell phones globally, transit operators now use these technologies to present information to their users. In addition to online maps and timetables, some transit operators now offer real-time information which allows passengers to know when the next vehicle will arrive, and expected travel times. The standardized GTFS data format for transit information allows many third-party software developers to produce web and smartphone app programs which give passengers customized updates regarding specific transit lines and stations of interest.

Safety and security.

Compared to other modes of transport, rapid transit has a good safety record, with few accidents. Rail transport is subject to strict safety regulations, with requirements for procedure and maintenance to minimize risk. Head-on collisions are rare due to use of double track, and low operating speeds reduce the occurrence and severity of rear-end collisions and derailments. Fire is more of a danger underground, such as the King's Cross fire in London in November 1987, which killed 31 people. Systems are generally built to allow evacuation of trains at many places throughout the system.  High platforms (usually over 1 meter / 3 feet) are a safety risk, as people falling onto the tracks have trouble climbing back. Platform screen doors are used on some systems to eliminate this danger.  Rapid transit facilities are public spaces and may suffer from security problems: petty crimes, such as pickpocketing and baggage theft, and more serious violent crimes, as well as sexual assaults on tightly packed trains and platforms. Security measures include video surveillance, security guards, and conductors. In some countries a specialized transit police may be established. These security measures are normally integrated with measures to protect revenue by checking that passengers are not travelling without paying. Some subway systems, such as the Beijing Subway, which is ranked by Worldwide Rapid Transit Data as the "World's Safest Rapid Transit Network" in 2015, incorporate airport-style security checkpoints at every station. Rapid transit systems have been subject to terrorism with many casualties, such as the 1995 Tokyo subway sarin gas attack and the 2005 "7/7" terrorist bombings on the London Underground.

Added features.

Some rapid transport trains have extra features such as wall sockets and internet connectivity. For example, the Hong Kong Mass Transit Railway (MTR) provides mobile data connection in the tunnels for selected service providers.

Infrastructure.

Most rapid transit trains are electric multiple units with lengths from three to over ten cars. Crew sizes have decreased throughout history, with some modern systems now running completely unstaffed trains. Other trains continue to have drivers, even if their only role in normal operation is to open and close the doors of the trains at stations. Power is commonly delivered by a third rail or by overhead wires. The whole London Underground network uses fourth rail and others use the linear motor for propulsion.  Most run on conventional steel railway tracks, although some use rubber tires, such as the Montreal Metro and Mexico City Metro and some lines in the Paris Métro. Rubber tires allow steeper gradients and a softer ride, but have higher maintenance costs and are less energy efficient. They also lose traction when weather conditions are wet or icy, preventing above-ground use of the Montréal Metro and limiting above-ground use on the Sapporo Municipal Subway but not rubber-tired systems in other cities.  High capacity Monorails with larger and longer trains can be classified as rapid transit systems. Such monorail systems recently started operating in Chongqing and São Paulo. Light metro is a subclass of rapid transit that has the speed and grade separation of a "full metro" but is designed for smaller passenger numbers. It often has smaller loading gauges, lighter train cars and smaller consists of typically two to four cars. Light metros are typically used as feeder lines into the main rapid transit system. For instance, the Wenhu Line of the Taipei Metro serves many relatively sparse neighbourhoods and feeds into and complements the high capacity metro lines.  Some systems have been built from scratch, others are reclaimed from former commuter rail or suburban tramway systems that have been upgraded, and often supplemented with an underground or elevated downtown section. At grade alignments with a dedicated right-of-way are typically used only outside dense areas, since they create a physical barrier in the urban fabric that hinders the flow of people and vehicles across their path and have a larger physical footprint. This method of construction is the cheapest as long as land values are low. It is often used for new systems in areas that are planned to fill up with buildings after the line is built.  Underground tunnels move traffic away from street level, avoiding delays caused by traffic congestion and leaving more land available for buildings and other uses. In areas of high land prices and dense land use, tunnels may be the only economic route for mass transportation. Cut-and-cover tunnels are constructed by digging up city streets, which are then rebuilt over the tunnel; alternatively, tunnel-boring machines can be used to dig deep-bore tunnels that lie further down in bedrock.  Elevated railways are a cheaper and easier way to build an exclusive right-of-way without digging expensive tunnels or creating barriers. In addition to street level railways they may also be the only other feasible alternative due to considerations such as a high water table close to the city surface that raises the cost of, or even precludes underground railways (e.g. Miami). Elevated guideways were popular around the beginning of the 20th century, but fell out of favor; they came back into fashion in the last quarter of the century—often in combination with driverless systems, for instance Vancouver's SkyTrain, London's Docklands Light Railway, the Miami Metrorail, and the Bangkok Skytrain.

Stations.

Stations function as hubs to allow passengers to board and disembark from trains. They are also payment checkpoints and allow passengers to transfer between modes of transport, for instance to buses or other trains. Access is provided via either island- or side platforms. Underground stations, especially deep-level ones, increase the overall transport time: long escalator rides to the platforms mean that the stations can become bottlenecks if not adequately built. Some underground and elevated stations are integrated into vast underground or skyway networks respectively, that connect to nearby commercial buildings. In suburbs, there may be a "park and ride" connected to the station.  To allow easy access to the trains, the platform height allows step-free access between platform and train. If the station complies with accessibility standards, it allows both disabled people and those with wheeled baggage easy access to the trains, though if the track is curved there can be a gap between the train and platform. Some stations use platform screen doors to increase safety by preventing people falling onto the tracks, as well as reducing ventilation costs.  The deepest station in the world is Arsenalna station in Kiev, Ukraine (105.5 m).  Particularly in the former Soviet Union and other Eastern European countries, but to an increasing extent elsewhere, the stations were built with splendid decorations such as marble walls, polished granite floors and mosaics—thus exposing the public to art in their everyday life, outside galleries and museums. The systems in Moscow, St. Petersburg, Tashkent and Kiev are widely regarded as some of the most beautiful in the world. Several other cities such as Stockholm, Montreal, Lisbon, Naples and Los Angeles have also focused on art, which may range from decorative wall claddings, to large, flamboyant artistic schemes integrated with station architecture, to displays of ancient artifacts recovered during station construction. It may be possible to profit by attracting more passengers by spending relatively small amounts on grand architecture, art, cleanliness, accessibility, lighting and a feeling of safety.

Modal tradeoffs and interconnections.

Since the 1980s, trams have incorporated several features of rapid transit: light rail systems (trams) run on their own rights-of-way, thus avoiding congestion; they remain on the same level as buses and cars. Some light rail systems have elevated or underground sections. Both new and upgraded tram systems allow faster speed and higher capacity, and are a cheap alternative to construction of rapid transit, especially in smaller cities.  A premetro design means that an underground rapid transit system is built in the city center, but only a light rail or tram system in the suburbs. Conversely, other cities have opted to build a full metro in the suburbs, but run trams in city streets to save the cost of expensive tunnels. In North America, interurbans were constructed as street-running suburban trams, without the grade-separation of rapid transit. Premetros also allow a gradual upgrade of existing tramways to rapid transit, thus spreading the investment costs over time. They are most common in Germany with the name Stadtbahn.  Suburban commuter rail is a heavy rail system that operates at a lower frequency than urban rapid transit, with higher average speeds, often only serving one station in each village and town. Commuter rail systems of some cities (such as German S-Bahns, Chennai Suburban, Australian suburban networks, Danish S-tog etc.) can be seen as the substitute for the city's rapid transit system providing frequent mass transit within city. In contrast, the mainly urban rapid transit systems in some cities (such as the Dubai Metro, Shanghai Metro, MetroSur of the Madrid Metro, Taipei Metro, Kuala Lumpur Rapid Transit etc.) have lines that fan out to reach the outer suburbs. With some other urban or "near urban" rapid transit systems (Guangfo Metro, Bay Area Rapid Transit, Los Teques Metro and Seoul Subway Line 7, etc.) serving bi- and multi-nucleus agglomerations.  Some cities have opted for two tiers of urban railways: an urban rapid transit system (such as the Paris Métro, Berlin U-Bahn, London Underground, Sydney Metro, Tokyo subway, and Philadelphia Subway) and a suburban system (such as their counterparts RER, S-Bahn, future Crossrail & London Overground, Sydney Trains, JR Urban Lines, and Regional Rail respectively). Such systems are known variously as S-trains, suburban service, or (sometimes) regional rail. The suburban systems may have their own purpose built trackage, run at similar "rapid transit-like" frequencies, and (in many countries) are operated by the national railway company. In some cities these suburban services run through tunnels in the city center and have direct transfers to the rapid transit system, on the same or adjoining platforms. California's BART, Federal District's Metrô-DF and Washington's Metrorail system is an example of a hybrid of the two: in the suburbs the lines function like a commuter rail line, with longer intervals and longer distance between stations; in the downtown areas, the stations become closer together and many lines interline with intervals dropping to typical rapid transit headways.

Costs, benefits, and impacts.

, 212 cities have built rapid transit systems. The capital cost is high, as is the risk of cost overrun and benefit shortfall; public financing is normally required. Rapid transit is sometimes seen as an alternative to an extensive road transport system with many motorways; the rapid transit system allows higher capacity with less land use, less environmental impact, and a lower cost.  Elevated or underground systems in city centers allow the transport of people without occupying expensive land, and permit the city to develop compactly without physical barriers. Motorways often depress nearby residential land values, but proximity to a rapid transit station often triggers commercial and residential growth, with large transit oriented development office and housing blocks being constructed. Also, an efficient transit system can decrease the economic welfare loss caused by the increase of population density in a metropolis.  Rapid transit systems have high fixed costs. Most systems are publicly owned, by either local governments, transit authorities or national governments. Capital investments are often partially or completely financed by taxation, rather than by passenger fares, but must often compete with funding for roads. The transit systems may be operated by the owner or by a private company through a public service obligation. The owners of the systems often also own the connecting bus or rail systems, or are members of the local transport association, allowing for free transfers between modes. Almost all transit systems operate at a deficit, requiring fare revenue, advertising and subsidies to cover costs.  The farebox recovery ratio, a ratio of ticket income to operating costs, is often used to assess operational profitability, with some systems including Hong Kong's MTR Corporation, and Taipei achieving recovery ratios of well over 100%. This ignores both heavy capital costs incurred in building the system, which are often subsidized with soft loans and whose servicing is excluded from calculations of profitability, as well as ancillary revenue such as income from real estate portfolios. Some systems, particularly Hong Kong's, extensions are partly financed by the sale of land whose value has appreciated by the new access the extension has brought to the area, a process known as value capture.

Rapid transit or mass rapid transit (MRT), also known as heavy rail, metro, subway, tube, U-Bahn, metropolitana or underground, is a type of high-capacity public transport generally found in urban areas. Unlike buses or trams, rapid transit systems are electric railways that operate on an exclusive right-of-way, which cannot be accessed by pedestrians or other vehicles of any sort, and which is often grade-separated in tunnels or on elevated railways.

地铁为铁路运输的一种形式,目前在中文的词意上有两种理解,但均与城市轨道交通系统相关:


Medical uses.

THC is an active ingredient in Nabiximols, a specific extract of "Cannabis" that was approved as a botanical drug in the United Kingdom in 2010 as a mouth spray for people with multiple sclerosis to alleviate neuropathic pain, spasticity, overactive bladder, and other symptoms. Nabiximols (as Sativex) is available as a prescription drug in Canada.

Pharmacology.

Mechanism of action.

The actions of THC result from its partial agonist activity at the cannabinoid receptor CB (K = 10 nM), located mainly in the central nervous system, and the CB receptor (K = 24 nM), mainly expressed in cells of the immune system. The psychoactive effects of THC are primarily mediated by the activation of cannabinoid receptors, which result in a decrease in the concentration of the second messenger molecule cAMP through inhibition of adenylate cyclase.  The presence of these specialized cannabinoid receptors in the brain led researchers to the discovery of endocannabinoids, such as anandamide and 2-arachidonoyl glyceride (2-AG). THC targets receptors in a manner far less selective than endocannabinoid molecules released during retrograde signaling, as the drug has a relatively low cannabinoid receptor efficacy and affinity. In populations of low cannabinoid receptor density, THC may act to antagonize endogenous agonists that possess greater receptor efficacy. THC is a lipophilic molecule and may bind non-specifically to a variety of entities in the brain and body, such as adipose tissue (fat). Due to its partial agonistic activity, THC appears to result in greater downregulation of cannabinoid receptors than endocannabinoids, further limiting its efficacy over other cannabinoids. While tolerance may limit the maximal effects of certain drugs, evidence suggests that tolerance develops irregularly for different effects with greater resistance for primary over side-effects, and may actually serve to enhance the drug's therapeutic window. However, this form of tolerance appears to be irregular throughout mouse brain areas. THC, as well as other cannabinoids that contain a phenol group, possesses mild antioxidant activity sufficient to protect neurons against oxidative stress, such as that produced by glutamate-induced excitotoxicity.

Pharmacokinetics.

THC is metabolized mainly to 11-OH-THC by the body. This metabolite is still psychoactive and is further oxidized to 11-nor-9-carboxy-THC (THC-COOH). In humans and animals, more than 100 metabolites could be identified, but 11-OH-THC and THC-COOH are the dominating metabolites. Metabolism occurs mainly in the liver by cytochrome P450 enzymes CYP2C9, CYP2C19, CYP2D6, and CYP3A4. More than 55% of THC is excreted in the feces and ≈20% in the urine. The main metabolite in urine is the ester of glucuronic acid and THC-COOH and free THC-COOH. In the feces, mainly 11-OH-THC was detected.

Physical and chemical properties.

Discovery and structure identification.

In 1940, cannabidiol was isolated and identified from "Cannabis sativa", and THC was isolated and described for its structure and synthesis in 1964.

Solubility.

As with many aromatic terpenoids, THC has a very low solubility in water, but good solubility in most organic solvents, specifically lipids and alcohols.

Total synthesis.

A total synthesis of the compound was reported in 1965; that procedure called for the intramolecular alkyl lithium attack on a starting carbonyl to form the fused rings, and a tosyl chloride mediated formation of the ether.

Biosynthesis.

In the "Cannabis" plant, THC occurs mainly as tetrahydrocannabinolic acid (THCA, 2-COOH-THC, THC-COOH). Geranyl pyrophosphate and olivetolic acid react, catalysed by an enzyme to produce cannabigerolic acid, which is cyclized by the enzyme THC acid synthase to give THCA. Over time, or when heated, THCA is decarboxylated, producing THC. The pathway for THCA biosynthesis is similar to that which produces the bitter acid humulone in hops.

No known lethal dose.

The Median lethal dose of THC in humans is not known; no human has ever been known to have died from it. A 1972 study gave up to 9000 mg/kg of THC to dogs and monkeys without any lethal effects. Some rats died within 72 hours after a dose of up to 3600 mg/kg.

Detection in body fluids.

THC and its 11-OH-THC and THC-COOH metabolites can be detected and quantified in blood, urine, hair, oral fluid or sweat using a combination of immunoassay and chromatographic techniques as part of a drug use testing program or in a forensic investigation.

Detection in breath.

Recreational use of cannabis is legal in many parts of North America, increasing the demand for THC monitoring methods in both personal and law enforcement uses. Breath sampling as a noninvasive method is in development to detect THC, which is difficult to quantify in breath samples. Scientists and industry are commercializing various types of breath analyzers to monitor THC in breath.

History.

THC was first isolated in 1969 by Raphael Mechoulam and Yechiel Gaoni at the Weizmann Institute of Science in Israel.<ref name="doi10.1021/ja01062a046"></ref>  At its 33rd meeting, in 2003, the World Health Organization Expert Committee on Drug Dependence recommended transferring THC to Schedule IV of the Convention, citing its medical uses and low abuse potential.

Society and culture.

Comparisons with medical cannabis.

Female cannabis plants contain at least 113 cannabinoids, including cannabidiol (CBD), thought to be the major anticonvulsant that helps people with multiple sclerosis; and cannabichromene (CBC), an anti-inflammatory which may contribute to the pain-killing effect of cannabis.

Regulation in Canada.

As of October 2018 when recreational use of cannabis was legalized in Canada, some 220 dietary supplements and 19 veterinary health products containing not more than 10 parts per million of THC extract were approved with general health claims for treating minor conditions.

Research.

The status of THC as an illegal drug in most countries imposes restrictions on research material supply and funding, such as in the United States where the National Institute on Drug Abuse and Drug Enforcement Administration continue to control the sole federally-legal source of cannabis for researchers. Despite an August 2016 announcement that licenses would be provided to growers for supplies of medical marijuana, no such licenses were ever issued, despite dozens of applications. Although cannabis is legalized for medical uses in more than half of the states of the United States, no products have been approved for federal commerce by the Food and Drug Administration, a status that limits cultivation, manufacture, distribution, clinical research, and therapeutic applications.  In April 2014, the American Academy of Neurology found evidence supporting the effectiveness of the cannabis extracts in treating certain symptoms of multiple sclerosis and pain, but there was insufficient evidence to determine effectiveness for treating several other neurological diseases. A 2015 review confirmed that medical marijuana was effective for treating spasticity and chronic pain, but caused numerous short-lasting adverse events, such as dizziness.

Tetrahydrocannabinol (THC) is one of at least 113 cannabinoids identified in cannabis. THC is the principal psychoactive constituent of cannabis. With chemical name (−)-"trans"-Δ9-tetrahydrocannabinol, the term "THC" also refers to cannabinoid isomers. Like most pharmacologically active secondary metabolites of plants, THC is a lipid found in cannabis, assumed to be involved in the plant's self-defense, putatively against insect predation, ultraviolet light, and environmental stress.

四氢大麻酚(英语:Tetrahydrocannabinol,简称THC),又称Δ-四氢大麻酚(Δ-THC)、Δ-THC(根据旧命名法),为大麻素之一,是大麻中的主要精神活性物质。


Iconography as a field of study.

Foundations of iconography.

Early Western writers who took special note of the content of images include Giorgio Vasari, whose "Ragionamenti", interpreting the paintings in the Palazzo Vecchio in Florence, reassuringly demonstrates that such works were difficult to understand even for well-informed contemporaries. Lesser known, though it had informed poets, painters and sculptors for over two centuries after its 1593 publication, was Cesare Ripa's emblem book "Iconologia". Gian Pietro Bellori, a 17th-century biographer of artists of his own time, describes and analyses, not always correctly, many works. Lessing's study (1796) of the classical figure Amor with an inverted torch was an early attempt to use a study of a type of image to explain the culture it originated in, rather than the other way round.  Iconography as an academic art historical discipline developed in the nineteenth-century in the works of scholars such as Adolphe Napoleon Didron (1806–1867), Anton Heinrich Springer (1825–1891), and Émile Mâle (1862–1954) all specialists in Christian religious art, which was the main focus of study in this period, in which French scholars were especially prominent. They looked back to earlier attempts to classify and organise subjects encyclopedically like Cesare Ripa and Anne Claude Philippe de Caylus's "Recueil d'antiquités égyptiennes, étrusques, grècques, romaines et gauloises" as guides to understanding works of art, both religious and profane, in a more scientific manner than the popular aesthetic approach of the time. These early contributions paved the way for encyclopedias, manuals, and other publications useful in identifying the content of art. Mâle's "l'Art religieux du XIIIe siècle en France" (originally 1899, with revised editions) translated into English as "The Gothic Image, Religious Art in France of the Thirteenth Century" has remained continuously in print.

Twentieth-century iconography.

In the early-twentieth century Germany, Aby Warburg (1866–1929) and his followers Fritz Saxl (1890–1948) and Erwin Panofsky (1892–1968) elaborated the practice of identification and classification of motifs in images to using iconography as a means to understanding meaning. Panofsky codified an influential approach to iconography in his 1939 "Studies in Iconology", where he defined it as "the branch of the history of art which concerns itself with the subject matter or meaning of works of art, as opposed to form," although the distinction he and other scholars drew between particular definitions of "iconography" (put simply, the identification of visual content) and "iconology" (the analysis of the meaning of that content), has not been generally accepted, though it is still used by some writers.  In the United States, to which Panofsky immigrated in 1931, students such as Frederick Hartt, and Meyer Schapiro continued under his influence in the discipline. In an influential article of 1942, "Introduction to an "Iconography of Mediaeval Architecture"", Richard Krautheimer, a specialist on early medieval churches and another German émigré, extended iconographical analysis to architectural forms.  The period from 1940 can be seen as one where iconography was especially prominent in art history. Whereas most iconographical scholarship remains highly dense and specialized, some analyses began to attract a much wider audience, for example Panofsky's theory (now generally out of favour with specialists) that the writing on the rear wall in the "Arnolfini Portrait" by Jan van Eyck turned the painting into the record of a marriage contract. Holbein's "The Ambassadors" has been the subject of books for a general market with new theories as to its iconography, and the best-sellers of Dan Brown include theories, disowned by most art historians, on the iconography of works by Leonardo da Vinci.  Technological advances allowed the building-up of huge collections of photographs, with an iconographic arrangement or index, which include those of the Warburg Institute and the Index of Medieval Art (formerly Index of Christian Art) at Princeton (which has made a specialism of iconography since its early days in America). These are now being digitised and made available online, usually on a restricted basis. With the arrival of computing, the Iconclass system, a highly complex way of classifying the content of images, with 28,000 classification types, and 14,000 keywords, was developed in the Netherlands as a standard classification for recording collections, with the idea of assembling huge databases that will allow the retrieval of images featuring particular details, subjects or other common factors. For example, the Iconclass code "71H7131" is for the subject of "Bathsheba (alone) with David's letter", whereas "71" is the whole "Old Testament" and "71H" the "story of David". A number of collections of different types have been classified using Iconclass, notably many types of old master print, the collections of the Gemäldegalerie, Berlin and the German Marburger Index. These are available, usually on-line or on DVD. The system can also be used outside pure art history, for example on sites like Flickr.

Brief survey of iconography.

Religious images are used to some extent by all major religions, including both Indian and Abrahamic faiths, and often contain highly complex iconography, which reflects centuries of accumulated tradition. Secular Western iconography later drew upon these themes.

Indian religious iconography.

Central to the iconography and hagiography of Indian religions are mudra or gestures with specific meanings. Other features include the aureola and halo, also found in Christian and Islamic art, and divine qualities and attributes represented by asana and ritual tools such as the dharmachakra, vajra, chhatra, sauwastika, phurba and danda. The symbolic use of colour to denote the Classical Elements or Mahabhuta and letters and bija syllables from sacred alphabetic scripts are other features. Under the influence of tantra art developed esoteric meanings, accessible only to initiates; this is an especially strong feature of Tibetan art. The art of Indian Religions esp. Hindus in its numerous sectoral divisions is governed by sacred texts called the Aagama which describes the ratio and proportion of the icon, called "taalmaana" as well as mood of the central figure in a context. For example, Narasimha an incarnation of Vishnu though considered a wrathful deity but in few contexts is depicted in pacified mood.  Although iconic depictions of, or concentrating on, a single figure are the dominant type of Buddhist image, large stone relief or fresco narrative cycles of the "Life of the Buddha", or tales of his previous lives, are found at major sites like Sarnath, Ajanta, and Borobudor, especially in earlier periods. Conversely, in Hindu art, narrative scenes have become rather more common in recent centuries, especially in miniature paintings of the lives of Krishna and Rama.

Christian iconography.

After an early period when aniconism was strong, surviving Early Christian art began, about two centuries after Christ, with small images in the Catacombs of Rome that show orans figures, portraits of Christ and some saints, and a limited number of "abbreviated representations" of biblical episodes emphasizing deliverance. From the Constantinian period monumental art borrowed motifs from Roman Imperial imagery, classical Greek and Roman religion and popular art – the motif of Christ in Majesty owes something to both Imperial portraits and depictions of Zeus. In the Late Antique period iconography began to be standardised, and to relate more closely to Biblical texts, although many gaps in the canonical Gospel narratives were plugged with matter from the apocryphal gospels. Eventually, the Church would succeed in weeding most of these out, but some remain, like the ox and ass in the Nativity of Christ.  After the period of Byzantine iconoclasm iconographical innovation was regarded as unhealthy, if not heretical, in the Eastern Church, though it still continued at a glacial pace. More than in the West, traditional depictions were often considered to have authentic or miraculous origins, and the job of the artist was to copy them with as little deviation as possible. The Eastern church also never accepted the use of monumental high relief or free-standing sculpture, which it found too reminiscent of paganism. Most modern Eastern Orthodox icons are very close to their predecessors of a thousand years ago, though development, and some shifts in meaning, have occurred – for example, the old man wearing a fleece in conversation with Saint Joseph usually seen in Orthodox Nativities seems to have begun as one of the shepherds, or the prophet Isaiah, but is now usually understood as the "Tempter" (Satan).  In both East and West, numerous iconic types of Christ, Mary and saints and other subjects were developed; the number of named types of icons of Mary, with or without the infant Christ, was especially large in the East, whereas Christ Pantocrator was much the commonest image of Christ. Especially important depictions of Mary include the Hodegetria and Panagia types. Traditional models evolved for narrative paintings, including large cycles covering the events of the Life of Christ, the Life of the Virgin, parts of the Old Testament, and, increasingly, the lives of popular saints. Especially in the West, a system of attributes developed for identifying individual figures of saints by a standard appearance and symbolic objects held by them; in the East they were more likely to identified by text labels.  From the Romanesque period sculpture on churches became increasingly important in Western art, and probably partly because of the lack of Byzantine models, became the location of much iconographic innovation, along with the illuminated manuscript, which had already taken a decisively different direction from Byzantine equivalents, under the influence of Insular art and other factors. Developments in theology and devotional practice produced innovations like the subject of the Coronation of the Virgin and the Assumption, both associated with the Franciscans, as were many other developments. Most painters remained content to copy and slightly modify the works of others, and it is clear that the clergy, by whom or for whose churches most art was commissioned, often specified what they wanted shown in great detail.  The theory of typology, by which the meaning of most events of the Old Testament was understood as a "type" or pre-figuring of an event in the life of, or aspect of, Christ or Mary was often reflected in art, and in the later Middle Ages came to dominate the choice of Old Testament scenes in Western Christian art. Whereas in the Romanesque and Gothic periods the great majority of religious art was intended to convey often complex religious messages as clearly as possible, with the arrival of Early Netherlandish painting iconography became highly sophisticated, and in many cases appears to be deliberately enigmatic, even for a well-educated contemporary. The subtle layers of meaning uncovered by modern iconographical research in works of Robert Campin such as the Mérode Altarpiece, and of Jan van Eyck such as the Madonna of Chancellor Rolin and the Washington Annunciation lie in small details of what are on first viewing very conventional representations. When Italian painting developed a taste for enigma, considerably later, it most often showed in secular compositions influenced by Renaissance Neo-Platonism.  From the 15th century religious painting gradually freed itself from the habit of following earlier compositional models, and by the 16th century ambitious artists were expected to find novel compositions for each subject, and direct borrowings from earlier artists are more often of the poses of individual figures than of whole compositions. The Reformation soon restricted most Protestant religious painting to Biblical scenes conceived along the lines of history painting, and after some decades the Catholic Council of Trent reined in somewhat the freedom of Catholic artists.

Secular Western iconography.

Secular painting became far more common in the West from the Renaissance, and developed its own traditions and conventions of iconography, in history painting, which includes mythologies, portraits, genre scenes, and even landscapes, not to mention modern media and genres like photography, cinema, political cartoons, comic books and anime.  Renaissance mythological painting was in theory reviving the iconography of its Classical Antiquity, but in practice themes like Leda and the Swan developed on largely original lines, and for different purposes. Personal iconographies, where works appear to have significant meanings individual to, and perhaps only accessible by, the artist, go back at least as far as Hieronymous Bosch, but have become increasingly significant with artists like Goya, William Blake, Gauguin, Picasso, Frida Kahlo and Joseph Beuys.

Iconography in disciplines other than art history.

Iconography, often of aspects of popular culture, is a concern of other academic disciplines including Semiotics, Anthropology, Sociology, Media Studies and Cultural Studies. These analyses in turn have affected conventional art history, especially concepts such as signs in semiotics. Discussing imagery as iconography in this way implies a critical "reading" of imagery that often attempts to explore social and cultural values. Iconography is also used within film studies to describe the visual language of cinema, particularly within the field of genre criticism. In the age of Internet, the new global history of the visual production of Humanity (Histiconologia ) includes History of Art and history of all kind of images or medias.

Articles with iconographical analysis of individual works.

A non-exhaustive list:

Iconography, as a branch of art history, studies the identification, description, and the interpretation of the content of images: the subjects depicted, the particular compositions and details used to do so, and other elements that are distinct from artistic style. The word "iconography" comes from the Greek ("image") and ("to write" or "to draw").

图像志(;英语:Iconography),又叫图像演变学、图像学,是艺术史的一个方法学。图像志早在希腊罗马时代的学术研究中意指「肖像学」,十六世纪以来则以「基督图像志」为主,直到1840年代,「基督图像志」仍是艺术研究的重要主题,在德国与法国皆有丰富的研究成果。二十世纪初,德国学界对图像志研究不再局限于基督宗教主题,在艺术史学科创立的同时,将图像志开辟成今日艺术史学中的一种方法学,也成为图像学(Iconology)方法应用的一个重要原则。图像志主要是研究同一类型图像的外在形象和内在意象,类型与范围无所不包,可以是色彩、轮廓、材料、结构、故事、意识形态、象征意义等等。主要是同一类型或针对同一主题,在不同的历史中所呈现的意义作探讨,包括起源、发展、转变、新加元素在不同时空的演变。相对于图像学,图像志更强调历史时间轴纵向的理解,图像学则强调当时代全面性、多元背景的深入研究,两种方法学的结合才能理解艺术作品的完整时代意义。现代艺术史学科创立的重要推手阿比·瓦尔堡,在1912年提出图像学这项重要艺术史研究理论时,便将图像志纳入其中。而今日具有指标性的图像学理论模型建构者潘诺夫斯基(Erwin Panofsky, 1892-1968),更将图像志明确纳入方法与原则之中。


Early life and education.

Queloz was born in Switzerland, on 23 February 1966.  Queloz studied at the University of Geneva where he subsequently obtained a MSc degree in physics in 1990, a DEA in Astronomy and Astrophysics in 1992, and a PhD degree in 1995 with Swiss astrophysicist Michel Mayor as his doctoral advisor.  In the area of religion The Daily Telegraph reports him as saying, "although not a believer himself, “Science inherited a lot from religions”".

Career and research.

While Queloz was a PhD candidate at the University of Geneva under Mayor, Mayor had been working on improving the accuracy of detection of the radial velocity of stellar objects via Doppler spectroscopy. Mayor had previously developed the CORAVEL spectrometer that helped to measure these velocities to an accuracy of 1 km/s. Mayor had found from CORAVEL that some binary star systems may in fact be single star systems with a substellar secondary object in their orbit. Queloz worked with Mayor to develop ELODIE, which was able to improve the accuracy of radial velocity measurements to 15 m/s to help better resolve these star systems' features.  ELODIE was installed at the Haute-Provence Observatory by 1994, and Queloz and Mayor began surveying the candidate systems. By July 1995, the pair had discovered that a large planet orbited 51 Pegasi; the planet was identified as 51 Pegasi b and determined to be of a Hot Jupiter. This was the first exoplanet to be discovered around a main sequence star. Queloz' and Mayor's discovery launched a more intensive search for exoplanets around other stars. For this achievement, they were awarded half of the 2019 Nobel Prize in Physics "for the discovery of an exoplanet orbiting a solar-type star".  Since these discoveries, Queloz became a professor at the University of Geneva, and in 2013, also became a professor at the Cavendish Laboratory at the University of Cambridge. He collaborated with the United Kingdom team of the Wide Angle Search for Planets (WASP) program which seeks to detect exoplanets via transit photometry, helping to provide spectrographic confirmation of their findings in 2007. He also participated in CoRoT, a planetary-detection system from orbital observatories, and helped to confirm the first detection of a rocky exoplanet, COROT-7b, in 2011. He is now involved in the Next Generation Transit Survey, a ground based successor to WASP. The CHEOPS science team is chaired by Queloz.  He is also a visiting scientist at MIT Kavli Institute for Astrophysics and Space Research.  Queloz received the 2011 BBVA Foundation Frontiers of Knowledge Award of Basic Sciences (co-winner with Mayor) for developing new astronomical instruments and experimental techniques that led to the first observation of planets outside the solar system. In 2017, he received the Wolf Prize in Physics and in 2019, the Nobel Prize in Physics.  In October 2019, related to his work in astronomy and exoplanet discoveries, Queloz predicted humans will discover extraterrestrial life in the next 30 years stating, "I can't believe we are the only living entity in the universe. There are just way [too] many planets, way too many stars, and the chemistry is universal. The chemistry that led to life has to happen elsewhere. So I am a strong believer that there must be life elsewhere."  In December 2019, Queloz took issue with those who are not supportive of helping to improve climate change, stating, “I think this is just irresponsible, because the stars are so far away I think we should not have any serious hope to escape the Earth [...] Also keep in mind that we are a species that has evolved and developed for this planet. We’re not built to survive on any other planet than this one [...] We’d better spend our time and energy trying to fix it.”

Awards.

Named after him

Didier Patrick Queloz (; born 23 February 1966) is a Swiss astronomer. He is a professor at the University of Cambridge, where he is also a fellow of Trinity College, Cambridge, as well as a professor at the University of Geneva. Together with Michel Mayor in 1995, he discovered 51 Pegasi b, the first extrasolar planet orbiting a sun-like star, 51 Pegasi. For this discovery, he shared the 2019 Nobel Prize in Physics with James Peebles and Michel Mayor. He also recently said that humans will likely find alien life in the next 30 years.

迪迪埃·帕特里克·奎洛兹(,1966年-2月23日|||}}),瑞士天文学家。他是剑桥大学的教授,也是剑桥三一学院的研究员,以及还是日内瓦大学的教授。 1995年,他与米歇尔·麦耶(Michel Mayor)一起发现了飞马座51b,这是第一个绕太阳状恒星飞马座51运行的太阳系外行星。 由于这一发现,他与吉姆·皮布尔斯(James Peebles)和米歇尔·麦耶分享了2019年诺贝尔物理学奖。


History.

After the description of fibrinogen and fibrin, Alexander Schmidt hypothesised the existence of an enzyme that converts fibrinogen into fibrin in 1872.  Prothrombin was discovered by Pekelharing in 1894.

Physiology.

Synthesis.

Thrombin is produced by the enzymatic cleavage of two sites on prothrombin by activated Factor X (Xa). The activity of factor Xa is greatly enhanced by binding to activated Factor V (Va), termed the prothrombinase complex. Prothrombin is produced in the liver and is co-translationally modified in a vitamin K-dependent reaction that converts 10-12 glutamic acids in the N terminus of the molecule to gamma-carboxyglutamic acid (Gla). In the presence of calcium, the Gla residues promote the binding of prothrombin to phospholipid bilayers. Deficiency of vitamin K or administration of the anticoagulant warfarin inhibits the production of gamma-carboxyglutamic acid residues, slowing the activation of the coagulation cascade.  In human adults, the normal blood level of antithrombin activity has been measured to be around 1.1 units/mL. Newborn levels of thrombin steadily increase after birth to reach normal adult levels, from a level of around 0.5 units/mL 1 day after birth, to a level of around 0.9 units/mL after 6 months of life.

Mechanism of action.

In the blood coagulation pathway, thrombin acts to convert factor XI to XIa, VIII to VIIIa, V to Va, fibrinogen to fibrin, and XIII to XIIIa.  Factor XIIIa is a transglutaminase that catalyzes the formation of covalent bonds between lysine and glutamine residues in fibrin. The covalent bonds increase the stability of the fibrin clot. Thrombin interacts with thrombomodulin.  As part of its activity in the coagulation cascade, thrombin also promotes platelet activation and aggregation via activation of protease-activated receptors on the cell membrane of the platelet.

Negative feedback.

Thrombin bound to thrombomodulin activates protein C, an inhibitor of the coagulation cascade. The activation of protein C is greatly enhanced following the binding of thrombin to thrombomodulin, an integral membrane protein expressed by endothelial cells. Activated protein C inactivates factors Va and VIIIa. Binding of activated protein C to protein S leads to a modest increase in its activity. Thrombin is also inactivated by antithrombin, a serine protease inhibitor.

Structure.

The molecular weight of prothrombin is approximately 72,000 Da. The catalytic domain is released from prothrombin fragment 1.2 to create the active enzyme thrombin, which has a molecular weight of 36,000 Da. Structurally, it is a member of the large PA clan of proteases.  Prothrombin is composed of four domains; an N-terminal Gla domain, two kringle domains and a C-terminal trypsin-like serine protease domain. Factor Xa with factor V as a cofactor leads to cleavage of the Gla and two Kringle domains (forming together a fragment called fragment 1.2) and leave thrombin, consisting solely of the serine protease domain.  As is the case for all serine proteases, prothrombin is converted to active thrombin by proteolysis of an internal peptide bond, exposing a new N-terminal Ile-NH3. The historic model of activation of serine proteases involves insertion of this newly formed N-terminus of the heavy chain into the β-barrel promoting the correct conformation of the catalytic residues. Contrary to crystal structures of active thrombin, hydrogen-deuterium exchange mass spectrometry studies indicate that this N-terminal Ile-NH3 does not become inserted into the β-barrel in the apo form of thrombin. However, binding of the active fragment of thrombomodulin appears to allosterically promote the active conformation of thrombin by inserting this N-terminal region.

Gene.

The thrombin (prothrombin) gene is located on the eleventh chromosome (11p11-q12).  There are an estimated 30 people in the world that have been diagnosed with the congenital form of Factor II deficiency, which should not be confused with the prothrombin G20210A mutation, which is also called the factor II mutation. Prothrombin G20210A is congenital.  Prothrombin G20210A is not usually accompanied by other factor mutations (i.e., the most common is factor V Leiden). The gene may be inherited heterozygous (1 pair), or much more rarely, homozygous (2 pairs), and is not related to gender or blood type. Homozygous mutations increase the risk of thrombosis more than heterozygous mutations, but the relative increased risk is not well documented. Other potential risks for thrombosis, such as oral contraceptives may be additive. The previously reported relationship of inflammatory bowel disease (i.e., Crohn's disease or ulcerative colitis) and prothrombin G20210A or factor V Leiden mutation have been contradicted by research.

Role in disease.

Activation of prothrombin is crucial in physiological and pathological coagulation. Various rare diseases involving prothrombin have been described (e.g., hypoprothrombinemia). Anti-prothrombin antibodies in autoimmune disease may be a factor in the formation of the lupus anticoagulant (also known as antiphospholipid syndrome). Hyperprothrombinemia can be caused by the G20210A mutation.  Thrombin, a potent vasoconstrictor and mitogen, is implicated as a major factor in vasospasm following subarachnoid hemorrhage. Blood from a ruptured cerebral aneurysm clots around a cerebral artery, releasing thrombin. This can induce an acute and prolonged narrowing of the blood vessel, potentially resulting in cerebral ischemia and infarction (stroke).  Beyond its key role in the dynamic process of thrombus formation, thrombin has a pronounced pro-inflammatory character, which may influence the onset and progression of atherosclerosis. Acting via its specific cell membrane receptors (protease activated receptors: PAR-1, PAR-3 and PAR-4), which are abundantly expressed in all arterial vessel wall constituents, thrombin has the potential to exert pro-atherogenic actions such as inflammation, leukocyte recruitment into the atherosclerotic plaque, enhanced oxidative stress, migration and proliferation of vascular smooth muscle cells, apoptosis and angiogenesis.  Thrombin is implicated in the physiology of blood clots. Its presence indicates the existence of a clot. In 2013 a system for detecting the presence of thrombin was developed in mice. It combines peptide-coated iron oxide attached to "reporter chemicals". When a peptide binds to a thrombin molecule, the report is released and appears in the urine where it can be detected. Human testing has not been conducted.

Applications.

Research tool.

Due to its high proteolytic specificity, thrombin is a valuable biochemical tool. The thrombin cleavage site (Leu-Val-Pro-Arg-Gly-Ser) is commonly included in linker regions of recombinant fusion protein constructs. Following purification of the fusion protein, thrombin can be used to selectively cleave between the Arginine and Glycine residues of the cleavage site, effectively removing the purification tag from the protein of interest with a high degree of specificity.

Medicine and surgery.

Prothrombin complex concentrate and fresh frozen plasma are prothrombin-rich coagulation factor preparations that can be used to correct deficiencies (usually due to medication) of prothrombin. Indications include intractable bleeding due to warfarin.  Manipulation of prothrombin is central to the mode of action of most anticoagulants. Warfarin and related drugs inhibit vitamin K-dependent carboxylation of several coagulation factors, including prothrombin. Heparin increases the affinity of antithrombin to thrombin (as well as factor Xa). The direct thrombin inhibitors, a newer class of medication, directly inhibit thrombin by binding to its active site.  Recombinant thrombin is available as a powder for reconstitution into aqueous solution. It can be applied topically during surgery, as an aid to hemostasis. It can be useful for controlling minor bleeding from capillaries and small venules, but ineffective and not indicated for massive or brisk arterial bleeding.

Food production.

Thrombin, combined with fibrinogen, is sold under the brand name Fibrimex for use as a binding agent for meat. Both proteins in Fibrimex derives from porcine or bovine blood. According to the manufacturer it can be used to produce new kinds of mixed meats (for example combining beef and fish seamlessly). The manufacturer also states that it can be used to combine whole muscle meat, form and portion these, thus cutting down on production costs without a loss in quality.  General secretary Jan Bertoft of Swedish Consumers' Association has stated that "there is danger of misleading the consumers since there is no way to tell this reconstituted meat from real meat".

Thrombin (, "fibrinogenase", "thrombase", "thrombofort", "topical", "thrombin-C", "tropostasin", "activated blood-coagulation factor II", "blood-coagulation factor IIa", "factor IIa", "E thrombin", "beta-thrombin", "gamma-thrombin") is a serine protease, an enzyme that, in humans, is encoded by the "F2" gene. Prothrombin (coagulation factor II) is proteolytically cleaved to form thrombin in the clotting process. Thrombin in turn acts as a serine protease that converts soluble fibrinogen into insoluble strands of fibrin, as well as catalyzing many other coagulation-related reactions.

凝血酶(英语:Thrombin,)是一种“胰蛋白酶样”丝氨酸蛋白酶蛋白质,在人体中被"F2"基因所编码。在凝血作用第一级级联反应中,凝血酶原(凝血因子II)被蛋白水解性切除以生成凝血酶,级联反应最终阻止了血液的继续流失。凝血酶转而作为一种丝氨酸蛋白酶以使可溶性的纤维蛋白原转变为不溶性的纤维蛋白,同时催化其他许多与凝血相关的反应。


尤利西斯·辛普森·格兰特

Early life and education.

Hiram Ulysses Grant was born in Point Pleasant, Ohio, on April 27, 1822, to Jesse Root Grant, a tanner and merchant, and Hannah Simpson Grant. His ancestors Matthew and Priscilla Grant arrived aboard the ship "Mary and John" at Massachusetts Bay Colony in 1630. Grant's great-grandfather fought in the French and Indian War, and his grandfather, Noah, served in the American Revolution at Bunker Hill. Afterward, Noah settled in Pennsylvania and married Rachel Kelley, the daughter of an Irish pioneer. Their son Jesse (Ulysses's father) was a Whig Party supporter and a fervent abolitionist. Jesse Grant moved to Point Pleasant in 1820 and found work as a foreman in a tannery. He soon met his future wife, Hannah, and the two were married on June 24, 1821. Hannah descended from Presbyterian immigrants from Ballygawley in County Tyrone, Ireland. Ten months after she was married, Hannah gave birth to

Early military career and personal life.

West Point and first assignment.

Grant's father wrote to Representative Thomas L. Hamer requesting that he nominate Ulysses to the United States Military Academy (USMA) at West Point, New York. Despite political differences with Jesse Root Grant, Hamer, a Democrat, nominated his 17-year-old son to West Point in Spring 1839. Grant was accepted on July 1, although he doubted his academic abilities. Hamer, unfamiliar with Grant, submitted an incorrect name to West Point. On September 14 Grant was enlisted Cadet "U.S. Grant" at the national academy. His nickname at West Point became "Sam" among army colleagues since the initials "U.S." also stood for "Uncle Sam".  Initially, Grant was indifferent to military life, but within a year he reexamined his desire to leave the academy and later wrote that "on the whole I like this place very much". While at the Academy, his greatest interest was horses, and he earned a reputation as the "most proficient" horseman. During the graduation ceremony, while riding "York", a large and powerful horse that only Grant could manage, he set a high-jump record that stood for 25 years. Seeking relief from military routine, he studied under Romantic artist Robert Walter Weir, producing nine

Marriage and family.

In Missouri, Grant visited Dent's family and became engaged to his sister, Julia, in 1844. Four years later on August 22, 1848, they were married at Julia's home in St. Louis. Grant's abolitionist father disapproved of the Dents owning slaves, and neither of Grant's parents attended the wedding. Grant was

Mexican–American War.

After rising tensions with Mexico following the United States' annexation of Texas, war broke out in 1846. During the conflict, Grant distinguished himself as a daring and competent soldier. Before the war President John Tyler had ordered Grant's unit to Louisiana as part of the Army of Observation under Major General Zachary Taylor. In September 1846, Tyler's successor, James K. Polk, unable to provoke Mexico into war at Corpus Christi, Texas, ordered Taylor to march 150 miles south to the Rio Grande. Marching south to Fort Texas, to prevent a Mexican siege, Grant experienced combat for the first time on May 8, 1846, at the Battle of Palo Alto.  Grant served as regimental quartermaster, but yearned for a combat role; when finally allowed, he led a charge at the Battle of Resaca de la Palma. He demonstrated his equestrian ability at the Battle of Monterrey by volunteering to carry a dispatch past snipers, where he hung off the side of his horse, keeping the animal between him and the enemy. Before leaving the city he assured some wounded Americans, he would

Post-war assignments and resignation.

Grant's first post-war assignments took him and Julia to Detroit on November 17, 1848, but he was soon transferred to Madison Barracks, a desolate outpost in upstate New York, in bad need of supplies and repair. After four months, Grant was sent back to his quartermaster job in Detroit. When the discovery of gold in California brought droves of prospectors and settlers to the territory, Grant and the 4th infantry were ordered to reinforce the small garrison there. Grant was charged with bringing the soldiers and a few hundred civilians from New York City to Panama, overland to the Pacific and then north to California. Julia, eight months pregnant with Ulysses Jr., did not accompany him. While Grant was in Panama, a cholera epidemic broke out and claimed the lives of many soldiers, civilians, and children. Grant established and organized a field hospital in Panama City, and moved the worst cases to a hospital barge one mile offshore. When orderlies protested having to attend to the sick, Grant did much of the nursing himself, earning high praise from

Civilian struggles, slavery, and politics.

At age 32, with no civilian vocation, Grant needed work to support his growing family. It was the beginning of seven years of financial struggles, poverty, and instability. Grant's father offered him a place in the Galena, Illinois branch of the family's leather business, but demanded Julia and the children stay in Missouri, with the Dents, or with the Grants in Kentucky. Grant and Julia declined the offer. In 1855, Grant farmed, using Julia's slave Dan, on his brother-in-law's property, "Wish-ton-wish", near St. Louis. The farm was not successful and to earn a living he sold firewood on St. Louis street corners.  The next year, the Grants moved to land on Julia's father's farm, and built a home called "Hardscrabble" on Grant's Farm. Julia described the rustic house as an "unattractive cabin", but made the dwelling as homelike as possible with the family's keepsakes and other belongings. Grant's family lacked money, clothes, and furniture, but always had enough food. During the Panic of 1857, which devastated many farmers, including Grant, who pawned his gold watch to pay for Christmas gifts for his family. In 1858, Grant rented out Hardscrabble and moved his family to Julia's father's 850-acre plantation. That fall, after suffering from malaria, Grant gave up farming.

Civil War.

On April 12, 1861, the American Civil War began when Confederate troops attacked Fort Sumter in Charleston, South Carolina. The news came as a shock in Galena, and Grant shared his neighbors' concern about the war. On April 15, Lincoln called for 75,000 volunteers. The next day, Grant attended a mass meeting to assess the crisis and encourage recruitment, and a speech by his father's attorney, John Aaron Rawlins, stirred Grant's patriotism. Ready to fight, Grant recalled with satisfaction, "I never went into our leather store again." On April 18, Grant chaired a second recruitment meeting, but turned down a captain's position as commander of the newly formed militia company, hoping his previous experience would aid him to obtain more senior military rank.

Early commands.

Grant's early efforts to be recommissioned were rejected by Major General George B. McClellan and Brigadier General Nathaniel Lyon. On April 29, supported by Congressman Elihu B. Washburne of Illinois, Grant was appointed military aide to Governor Richard Yates and mustered ten regiments into the Illinois militia. On June 14, again aided by Washburne, Grant was promoted to Colonel and put in charge of the unruly 21st Illinois Volunteer Infantry Regiment, which he soon restored to good order and discipline. Colonel Grant and his 21st Regiment were transferred to Missouri to dislodge Confederate forces.  On August 5, with Washburne's

Belmont, Forts Henry and Donelson.

On November 2, 1861, Lincoln removed Frémont from command, freeing Grant to attack Confederate soldiers encamped in Cape Girardeau, Missouri. On November 5, Grant, along with Brigadier General John A. McClernand, landed 2,500 men at Hunter's Point, and on November 7 engaged the Confederates at the Battle of Belmont. The Union army took the camp, but the reinforced Confederates under Brigadier Generals Frank Cheatham and Gideon J. Pillow forced a chaotic Union retreat. Grant had wanted to destroy Confederate strongholds at both Belmont, Missouri and Columbus, Kentucky, but was not given enough troops and was only able to disrupt their

Shiloh and aftermath.

With great armies now massing, it was widely thought in the North that another western battle might end the war. Grant, reinstated by Halleck at the urging of Lincoln and Secretary of War Edwin Stanton, left Fort Henry and traveled by boat up the Tennessee River to rejoin his army with orders to advance with the Army of the Tennessee into Tennessee. Grant's main army was located at Pittsburg Landing, while 40,000 Confederate troops converged at Corinth, Mississippi. Brigadier General William Tecumseh Sherman assured Grant that his green troops were ready for an attack. Grant agreed and wired Halleck with their assessment. Grant wanted to attack the Confederates at Corinth, but Halleck ordered him not to attack until Major General Don Carlos Buell arrived

Vicksburg campaign.

The Union capture of Vicksburg, the last Confederate stronghold on the Mississippi, was vital, and would split the Confederacy in two. Lincoln, however, appointed McClernand for the job, rather than Grant or Sherman. Halleck, who retained power over troop displacement, ordered McClernand to Memphis, and placed him and his troops under Grant's authority. On November 13, 1862, Grant captured Holly Springs and advanced to Corinth. Grant's plan was to march south to Jackson, and attack Vicksburg overland, while Sherman would attack Vicksburg from Chickasaw Bayou. However, Confederate cavalry raids on December 11 and 20, 1862, broke Union communications and recaptured Holly Springs, preventing Grant and Sherman from converging on Vicksburg. Grant observed sabotage by civilians who had feigned loyalty and complained: "Guerrillas are

Chattanooga and promotion.

Lincoln promoted Grant to major general and assigned him command of the newly formed Division of the Mississippi on October 16, 1863, including command of the Armies of the Ohio, Tennessee, and Cumberland. After the Battle of Chickamauga, the Army of the Cumberland retreated into Chattanooga where they became trapped. Grant arrived in Chattanooga on horseback, assisted by Major General Joseph Hooker, with plans to resupply the city and break the siege. Union forces captured Brown's Ferry and opened a supply line to Bridgeport.  On November 23, Grant organized three armies to attack at Missionary Ridge and Lookout Mountain. Two days later, Hooker's forces took Lookout Mountain. Grant ordered Major General George Henry Thomas to advance when Sherman's army failed to take Missionary Ridge from the northeast. The Army of the Cumberland, led by Major General Philip Sheridan and Brigadier General Thomas J. Wood, charged uphill and captured the Confederate entrenchments at the top, forcing a retreat. The decisive battle gave the Union control of Tennessee and opened Georgia, the Confederate heartland, to Union invasion. Grant was given an enormous thoroughbred horse, "Cincinnati", by a thankful

Overland Campaign.

The Overland Campaign was a series of brutal battles fought in Virginia for seven weeks during May and June 1864. Sigel's and Butler's efforts failed, and Grant was left alone to fight Lee. On the morning of Wednesday, May 4, Grant dressed in full uniform, sword at his side, led the army out from his headquarters at Culpeper towards Germanna Ford. They crossed the Rapidan unopposed, while supplies were transported on four pontoon bridges. On May 5, the Union army attacked Lee in the Wilderness, a three-day battle with estimated casualties of 17,666 Union and 11,125 Confederate. Rather than retreat, Grant flanked Lee's army to the southeast

Appomattox campaign, and victory.

On April 2, Grant ordered a general assault on Lee's entrenched forces. Union troops took Petersburg and captured Richmond the next day. Lee and part of his army broke free and attempted to link up with the remnants of Joseph E. Johnston's defeated army, but Sheridan's cavalry stopped the two armies from converging, cutting them off from their supply trains. Grant was in communication with Lee before he entrusted his aide Orville Babcock to carry his last dispatch to Lee requesting his surrender with instructions to escort him to a meeting place of Lee's choosing. Grant immediately rode west, bypassing Lee's army, to join Sheridan who had captured Appomattox Station, blocking Lee's escape route. On his way, Grant received a letter sent by Lee informing him

Lincoln's assassination.

On April 14, 1865, five days after Grant's victory at Appomattox, he attended a cabinet meeting in Washington. Lincoln invited him and his wife to Ford's Theater, but they declined as upon his wife Julia's urging, had plans to travel to Philadelphia. In a conspiracy that also targeted top cabinet members in one last effort to topple the Union, Lincoln was fatally shot by John Wilkes Booth at the theater, and died the next

Commanding General.

At the war's end, Grant remained commander of the army, with duties that included dealing with Maximilian and French troops in Mexico, enforcement of Reconstruction in the former Confederate states, and supervision of Indian wars on the western Plains. After the Grand Review of the Armies, Lee and his generals were indicted for treason in Virginia. Johnson demanded they be put on trial, but Grant insisted that they should not be tried, citing his Appomatox amnesty. Johnson backed down, so charges against Lee were dropped. Grant secured a house for his family in Georgetown Heights in 1865, but instructed Elihu Washburne that for political purposes his legal residence remained in Galena, Illinois. That same year, Grant spoke at Cooper Union in New York in support of Johnson's presidency. Further travels that summer took the Grants to Albany, New York, back to Galena, and throughout Illinois and Ohio, with enthusiastic receptions. On July 25, 1866, Congress promoted Grant to the newly created rank of General of the Army of the United States.

Reconstruction.

Reconstruction was a turbulent period from 1863 to 1877 when former Confederate states were readmitted to the Union, and fierce controversy arose over the status of both the defeated Confederates and the former slaves. In November 1865, Johnson sent Grant on a fact-finding mission to the South. Grant recommended continuation of the Freedmen's Bureau, which Johnson opposed, but advised against using black troops, which he believed encouraged an alternative to farm labor. Grant did not believe the people of

Break from Johnson.

Grant was initially optimistic about Johnson, saying he was satisfied the nation had "nothing to fear" from the Johnson administration. Despite differing styles, Grant got along cordially with Johnson, and attended cabinet meetings concerning Reconstruction. By February 1866, the relationship began to break down. Johnson opposed Grant's closure of the "Richmond Examiner" for disloyal editorials and his enforcement of the Civil Rights Act of 1866, passed over Johnson's veto. Needing Grant's popularity, Johnson took Grant on his "Swing Around the Circle" tour, a failed attempt to gain national support for lenient policies toward the South. Grant privately called Johnson's speeches a "national disgrace" and he left the tour early. On March 2, 1867, overriding Johnson's veto, Congress passed the first of three Reconstruction Acts, using military officers to enforce policy. Protecting Grant, Congress passed the Command of the Army Act, preventing his removal or relocation,

Election of 1868.

When the Republican Party met at the 1868 Republican National Convention in Chicago, the delegates unanimously nominated Grant for president and Speaker of the House Schuyler Colfax for vice president. Although Grant had preferred to remain in the army, he accepted the Republican nomination, believing that he was the only one who could unify the nation. The Republicans advocated "equal civil and political rights to all" and African American enfranchisement. The Democrats, having abandoned Johnson, nominated former governor Horatio Seymour of New York for president and Francis P. Blair of Missouri for vice president. The Democrats advocated the immediate restoration of former Confederate states to the Union and amnesty from "all past political offenses".  Grant played no overt

Presidency (1869–1877).

On March 4, 1869, Grant was sworn in as the eighteenth President of the United States by Chief Justice Salmon P. Chase. In his inaugural address, Grant urged the ratification of the Fifteenth Amendment, while large numbers of African Americans attended his inauguration. He also urged that bonds issued during the Civil War should be paid in gold and called for "proper treatment" of Native Americans and encouraged their "civilization and ultimate citizenship".  Grant's sparked both criticism and approval. He appointed Elihu B. Washburne Secretary of State and John A. Rawlins Secretary of War. Washburne resigned, and Grant appointed him Minister to France. Grant then appointed former New York Senator Hamilton Fish Secretary of State. Rawlins died in office, and Grant appointed William W. Belknap Secretary of War. Grant appointed New York businessman Alexander T. Stewart Secretary of Treasury, but Stewart was found legally ineligible to hold office by a 1789 law. Grant then appointed Massachusetts Representative George S. Boutwell Secretary of Treasury. Philadelphia businessman Adolph E. Borie was appointed Secretary of Navy, but found the job stressful and resigned. Grant then appointed New Jersey's attorney general, George M. Robeson, Secretary of Navy. Former Ohio Governor Jacob D. Cox (Interior,) former Maryland Senator John Creswell (Postmaster-General,) and Ebenezer Rockwood Hoar (Attorney General) rounded out the cabinet.  Grant nominated Sherman to succeed him as general-in-chief and gave him control over war bureau chiefs. When Rawlins took over the War Department, he complained to Grant that Sherman was given too much authority. Grant reluctantly revoked his own order, upsetting Sherman and damaging their wartime friendship. James Longstreet, a former Confederate general who had endorsed Grant's nomination, was nominated for the position of Surveyor of Customs of the port of New Orleans, and was met with general amazement, and seen as a genuine effort to unite the North and South. In March 1872, Grant signed legislation that established Yellowstone National Park, the first national park. Grant was sympathetic to women's rights; including support of female suffrage, saying he wanted "equal rights to all citizens."  Grant appointed more than fifty Jewish people to federal office, including consuls, district attorneys, and deputy postmasters. He appointed Edward S. Salomon territorial governor of Washington, the first time an American Jewish man occupied a governor's seat. Grant was sympathetic to the plight of persecuted Jewish people. In November 1869, reports surfaced of the Russian Czar Alexander II expelling 2,000 Jewish families to the Interior for smuggling. In response, Grant publicly supported the Jewish American "B'nai B'rith" petition against the Czar. In December 1869, Grant appointed a Jewish journalist as Consul to Romania, to protect Jewish people from "severe oppression".  In 1875, Grant proposed a constitutional amendment that limited religious indoctrination in public schools. Instruction of "religious, atheistic, or pagan tenets," would be banned, while funding "for the benefit or in aid, directly or indirectly, of any religious sect or denomination," would be prohibited. Schools would be for all children "irrespective of sex, color, birthplace, or religions." Grant's views were incorporated into the Blaine Amendment, but it was defeated by the Senate.

Post-presidency.

After leaving the White House, Grant said he "was never so happy in my life." The Grants left Washington for New York, to attend the birth of their daughter Nellie's child, staying at Hamilton Fish's residence. Calling themselves "waifs," the Grants toured Cincinnati, St. Louis, Chicago, and Galena, without a clear idea of where they would live afterwards.

World tour and diplomacy.

For some years Grant had entertained the idea of taking a long deserved vacation after his presidency and, after liquidating one of his investments to finance the venture, the Grants set out on a world tour that lasted approximately two and a half years. Grant's voyage abroad was funded by a Nevada-based mining company investment he made that earned him $25,000. (~$600,000 in 2019 dollars) Preparing for the tour, they arrived in Philadelphia on May 10, 1877, and were honored with celebrations during the week before their departure. On May 16, Grant and Julia left for England aboard the SS "Indiana". During the tour the Grants made stops in Europe, Africa, India, and points in the Middle East and Far East, meeting with

Third term attempt.

Stalwarts, led by Grant's old political ally, Roscoe Conkling, saw Grant's renewed popularity as an opportunity to regain power, and sought to nominate him for the presidency in 1880. Opponents called it a violation of the unofficial two-term rule in use since George Washington. Grant said nothing publicly but wanted the job and encouraged his men. Washburne urged him to run; Grant demurred, saying he would be happy for the Republicans to win with another candidate, though he preferred James G. Blaine to John Sherman. Even so, Conkling and John A. Logan began to organize delegates in Grant's favor. When the convention convened in Chicago in June, there were more delegates pledged to Grant than to any other candidate, but he was still short of a majority vote

Business failures.

When Grant had returned to America from his costly world tour, he had depleted most of his savings and needed to earn money and find a new home. Wealthy friends bought him a home on Manhattan's Upper East Side, and to make an income, Grant, Jay Gould, and former Mexican Finance Secretary Matías Romero chartered the Mexican Southern Railroad, with plans to build a railroad from Oaxaca to Mexico City. Grant urged Chester A. Arthur, who had succeeded Garfield as president in 1881, to negotiate a free trade treaty with Mexico. Arthur and the Mexican government agreed, but the United States Senate rejected the treaty in 1883. The railroad was similarly unsuccessful, falling into bankruptcy the following year.  At the same time, Grant's son Buck had opened a Wall Street brokerage house with Ferdinand Ward—although a confidence man who swindled numerous wealthy men, Ward was at the time regarded as a rising star on Wall Street. The firm, Grant & Ward, was initially successful. In 1883, Grant joined the firm and invested $100,000 of his own money. Grant, however, warned Ward that if his firm engaged in government business he would dissolve

Memoirs, pension, and death.

Throughout his career, Grant repeatedly told highly detailed stories of his military experiences, often making slight mistakes in terms of dates and locations. As a poor hardscrabble farmer in St. Louis just before the war, he kept his neighbors spellbound till midnight "listening intently to his vivid narrations of Army experiences." In calm moments during the Civil War, he often spoke of his recent experiences, typically "in terse and often eloquent language." Grant's interpretations changed over time—in his letters written during the Mexican War period, there is no criticism of the war. By contrast his "Memoirs" are highly critical of the political aspects, condemning the war as unwarranted aggression by the United States. Grant told and retold his war stories so many times that

Historical reputation.

Grant was hailed across the North as the winning general in the American Civil War and overall his military reputation has held up fairly well. Achieving great national fame for his victories at Vicksburg and the surrender at Appomattox, he was widely credited as the General who "saved the Union". Criticized by the South for using excessive force, his overall military reputation stands intact. Grant's drinking was often exaggerated by the press and falsely stereotyped by many of his rivals and critics. Grant's reputation fell when the popularity of the pro-Confederate Lost Cause theory and the Dunning School movement grew in the late 19th and early 20th centuries.  In the 1950s, some historians made a reassessment of Grant's military career, shifting the analysis of

Memorials and presidential library.

Several memorials honor Grant. In addition to his mausoleum—Grant's Tomb in New York City—there is the Ulysses S. Grant Memorial at the foot of Capitol Hill in Washington, D.C. Created by sculptor Henry Merwin Shrady and architect Edward Pearce Casey, and dedicated in 1922, it overlooks the Capitol Reflecting Pool. In 2015, restoration work began, which is expected to be completed before the bicentennial of Grant's birth in 2022.  The Ulysses S. Grant National Historic Site near St. Louis, and several other sites in Ohio and Illinois memorialize Grant's life. The U.S. Grant Cottage State Historic Site, located at the top of Mount McGregor in Wilton, New York, preserves the house in which he completed his memoirs and died. There are smaller memorials in Chicago's Lincoln Park and Philadelphia's Fairmount Park. Named in

Bibliography.

Biographical  Military & politics  Primary sources  Historiography

Ulysses S. Grant (born Hiram Ulysses Grant; April 27, 1822July 23, 1885) was an American soldier and politician who served as the 18th president of the United States from 1869 to 1877. Before his presidency, Grant led the Union Army as Commanding General of the United States Army in winning the American Civil War. As president, Grant worked with the Radical Republicans in the Reconstruction of the Union while having to deal with corruption in his administration.

尤利西斯·S·格兰特(英语:Ulysses S Grant;1822年-4月27日-1885年-7月23日),美国上将、政治人物,第18任美国总统。格兰特是一名战争英雄,政治家,被共和党一致提名,于1868年当选美国总统。