The short version of shelf life fits in a sentence. The long version — which is the one that helps — is below.
Reviewed 2025-10-28. Anything still debated is marked as such rather than presented as settled.
当时的短肽研究普遍关注能否穿越血脑屏障、在低剂量下产生中枢效应，Semax 属于这一路线。鼻内给药是其主要使用方式，俄语文献报道的适应症涵盖缺血性卒中、短暂性脑缺血发作、认知功能减退以及视神经病变。这些研究大多发表在当地期刊上，样本规模与终点设置同西方试验惯例存在差异，国际同行对其临床证据的强度看法不一。
各国监管态度分化明显。俄罗斯按处方药管理，部分东欧国家留有使用记录；欧盟与美国未批准其作为药物上市，市面流通品通常标注为研究用化学品。身份差异意味着标示含量、纯度与无菌性缺少统一核查。体育领域还牵涉反兴奋剂名录，跨境携带则受目的地药品法规约束。
Semax 是人工设计的七肽，序列为 Met-Glu-His-Phe-Pro-Gly-Pro，骨架取自促肾上腺皮质激素片段 ACTH(4-10)。它于二十世纪八十年代在苏联的分子遗传学研究机构内合成。设计目标是保留该片段与注意力和记忆相关的活性，同时剔除促皮质激素释放等内分泌作用。此后俄罗斯将其登记为药品并进入临床使用。
Lyophilised powder is normally kept at -20 °C in a desiccated container, with some suppliers recommending -80 °C for long-term archival storage. Repeated freeze-thaw cycles are the most common cause of avoidable loss, so aliquoting before freezing reduces variability between working sessions. Dissolved peptide is far less stable than the dry solid and is usually prepared fresh or held briefly at 4 °C. Aqueous solutions support both hydrolysis of the backbone and oxidation of the N-terminal methionine, and these two routes dominate degradation under ordinary laboratory conditions.
Identity and purity are confirmed with reversed-phase high-performance liquid chromatography, typically monitored at 214 nanometres where the peptide bond absorbs. Mass spectrometry, either electrospray or MALDI-TOF, verifies molecular mass against the theoretical value and detects truncation or adduct formation. Amino acid analysis and peptide mapping provide additional confirmation when required. The most frequently reported impurities are deletion sequences from incomplete coupling, methionine sulfoxide from oxidation, and dimeric species formed through non-covalent aggregation. Impurity profiles depend strongly on the synthesis and purification route chosen by the producer.
| Property | Value | Notes |
|---|---|---|
| 结构类别 | 线性合成七肽 | 无环化结构，不含二硫键 |
| 氨基酸序列 | Met-Glu-His-Phe-Pro-Gly-Pro | N 端为甲硫氨酸 |
| 分子量 | 约 814 Da | 游离碱形式的计算值 |
| 外观 | 白色至类白色粉末 | 具吸湿性 |
| 溶解性 | 易溶于水 | 亦可溶于甲醇等极性溶剂 |
Semax is a synthetic heptapeptide with the sequence Met-Glu-His-Phe-Pro-Gly-Pro. It corresponds to the ACTH(4-7) fragment extended at the C-terminus by a Pro-Gly-Pro tripeptide, an addition intended to slow enzymatic breakdown. The molecular formula is C37H51N9O10S and the molecular mass is approximately 814 daltons. In the literature it is often described as an ACTH(4-10) analog, although that label reflects a naming convention as much as a precise structural relationship. The compound was developed in Russia and remains most closely associated with that research tradition.
Laboratory descriptions of the material are consistent across suppliers. It appears as a white to off-white lyophilized powder that dissolves readily in water and in polar organic solvents such as dimethyl sulfoxide. Aqueous solutions are clear and colorless at low concentrations. Because the peptide contains methionine, oxidation at the sulfur atom is a recognized degradation pathway, and handling notes usually call for protected, desiccated storage. Reported purity for research-grade lots is generally above 95 percent as measured by reversed-phase high-performance liquid chromatography.
The compound is registered in Russia as a pharmaceutical product, most commonly formulated as a nasal solution, and has been used in that setting since the 1990s. Outside that jurisdiction it is generally handled as a research chemical rather than an approved medicine. Regulatory status therefore differs sharply between countries, and material sold internationally may not correspond to the Russian pharmaceutical formulation. Documentation with commercial samples is typically limited to a certificate of analysis covering purity and identity, not clinical status or local legal classification.
Semax is normally supplied as a lyophilized powder, and that form is the most stable. Suppliers commonly recommend storage at -20 °C in a desiccated container protected from light, with short-term handling at room temperature limited to weighing and transfer. Powder that has absorbed moisture degrades faster, so vials should be warmed to ambient temperature before opening to prevent condensation on the contents. Hygroscopic behavior is typical of short hydrophilic peptides, and humidity control matters more than temperature alone for long-term retention.
Once dissolved, the peptide is considerably less stable than the solid. Aqueous solutions are usually prepared at neutral to slightly acidic pH, filtered, and divided into single-use aliquots before freezing. Repeated freeze-thaw cycles are a common cause of avoidable loss and are best prevented by never refreezing a thawed aliquot. Adsorption to plastic and glass surfaces can lower the measured concentration of dilute solutions, particularly below roughly 0.1 mg/mL. Buffer choice, salt content, and container material all influence how much peptide remains detectable after storage.
Semax is a synthetic heptapeptide with the sequence Met-Glu-His-Phe-Pro-Gly-Pro. It was derived from the ACTH(4-10) fragment, a short segment of adrenocorticotropic hormone that lacks the hormonal activity associated with the full-length peptide. Researchers at the Institute of Molecular Genetics in Moscow developed the compound during the 1980s. It has been registered as a pharmaceutical product in Russia and several neighbouring countries, where it is supplied as a nasal solution, and it is also sold internationally as a research chemical.
The proposed mechanism centres on neurotrophic signalling rather than direct receptor activation. Semax is reported to increase expression of brain-derived neurotrophic factor and nerve growth factor in several brain regions, and to shift the balance between excitatory and inhibitory neurotransmitter systems. Interaction with melanocortin receptors has been suggested because of the parent ACTH fragment. Many of these findings come from rodent studies, and the extent to which they translate to human physiology remains an open question.
Published studies are dominated by animal models of stroke, ischemia, and cognitive impairment, with a smaller number of human trials conducted in Russia. Many of the human reports are small, single-center, and published in Russian-language journals, which limits independent scrutiny. Outcome measures vary between studies and often rely on clinician-rated scales rather than objective biomarkers. Systematic reviews have noted the methodological weaknesses and called for larger, preregistered trials before firm conclusions can be drawn.
Claims about enhanced focus, memory, or mood in healthy people rest mostly on anecdotal reports and community discussion rather than on controlled data. It remains unclear whether any cognitive benefit observed in patients recovering from brain injury would extend to uninjured users. Dose-response relationships, long-term safety, and interactions with other drugs are not well characterized in the peer-reviewed literature. Questions about optimal route of administration and treatment duration likewise remain open.
A nanodisc is a synthetic model membrane system which assists in the study of membrane proteins. Nanodiscs are discoidal proteins in which a lipid bilayer is surrounded by molecules that are amphipathic molecules including proteins, peptides, and synthetic polymers. It is composed of a lipid bilayer of phospholipids with the hydrophobic edge screened by two amphipathic proteins. These proteins are called membrane scaffolding proteins (MSP) and align in double belt formation. Nanodiscs are structurally very similar to discoidal high-density lipoproteins (HDL) and the MSPs are modified versions of apolipoprotein A1 (apoA1), the main constituent in HDL. Nanodiscs are useful in the study of membrane proteins because they can solubilise and stabilise membrane proteins and represent a more native environment than liposomes, detergent micelles, bicelles and amphipols. The art of making nanodiscs has progressed past using only the MSPs and lipids to make particles, leading to alternative strategies like peptide nanodiscs that use simpler proteins and synthetic nanodiscs that do not need any proteins for stabilization.
This response is activated by the binding of complement proteins to carbohydrates on the surfaces of microbes, or to antibodies that have attached to these microbes, which creates a cell signal that triggers a rapid killing response, whose speed is significantly amplified after sequential proteolytic activation of complement protease molecules, controlled by positive feedback. The cascade results in the production of peptides that attract immune cells; increase vascular permeability; and opsonize the surface of a pathogen, marking it for destruction. Complement binding can also kill cells directly by disrupting their plasma membrane via a membrane attack complex.
Supercritical carbon dioxide (sCO2) is a fluid state of carbon dioxide where it is held at or above its critical temperature and critical pressure. Carbon dioxide usually behaves as a gas in air at standard temperature and pressure (STP), or as a solid called dry ice when cooled and/or pressurised sufficiently. If the temperature and pressure are both increased from STP to be at or above the critical point for carbon dioxide, it can adopt properties midway between a gas and a liquid. More specifically, it behaves as a supercritical fluid above its critical temperature (304.128 K, 30.9780 °C, 87.7604 °F) and critical pressure (7.3773 MPa, 72.808 atm, 1,070.0 psi, 73.773 bar), expanding to fill its container like a gas but with a density like that of a liquid. Supercritical CO2 is becoming an important commercial and industrial solvent due to its role in chemical extraction, in addition to its relatively low toxicity and environmental impact. The relatively low temperature of the process and the stability of CO2 also allows compounds to be extracted with little damage or denaturing. In addition, the solubility of many extracted compounds in CO2 varies with pressure, permitting selective extractions.
Sources: en.wikipedia.org
== Applications == DTT is used as a reducing or "deprotecting" agent for thiolated DNA. The terminal sulfur atoms of thiolated DNA have a tendency to form dimers in solution, especially in the presence of oxygen. Dimerization greatly lowers the efficiency of subsequent coupling reactions such as DNA immobilization on gold in biosensors. Typically DTT is mixed with a DNA solution and allowed to react, and then is removed by filtration (for the solid catalyst) or by chromatography (for the liquid form). The DTT removal procedure is often called "desalting." Generally, DTT is used as a protecting agent that prevents oxidation of thiol groups. DTT is frequently used to reduce the disulfide bonds of proteins and, more generally, to prevent intramolecular and intermolecular disulfide bonds from forming between cysteine residues of proteins. However, even DTT cannot reduce buried (solvent-inaccessible) disulfide bonds, so reduction of disulfide bonds is sometimes carried out under denaturing conditions (e.g., at high temperatures, or in the presence of a strong denaturant such as 6 M guanidinium chloride, 8 M urea, or 1% sodium dodecylsulfate). DTT is oftentimes used along with sodium dodecylsulfate in SDS-PAGE to further denature proteins by reducing their disulfide bonds to allow for better separation of proteins during electrophoresis. Because of the ability to reduce disulfide bonds, DTT can be used to denature CD38 on red blood cells. DTT will also denature antigens in the Kell, Lutheran, Dombrock, Cromer, Cartwright, LW and Knops blood group systems.
Multicolumn countercurrent solvent gradient purification (MCSGP) is a form of chromatography that is used to separate or purify biomolecules from complex mixtures. It was developed at the Swiss Federal Institute of Technology Zürich by Aumann and Morbidelli. The process consists of two to six chromatographic columns which are connected to one another in such a way that as the mixture moves through the columns the compound is purified into several fractions.
Originally a Russian production, all in Russian with subtitles, produced by Maciej Drygas 15 October High Anxiety, about lifts and the required extensive technology of tall office buildings; Canary Wharf Tower (One Canada Square) had 50 floors with 36 lifts, which could travel up to 13.5 mph; Jim Fortune of Lerch Bates; novelist Philip Kerr; Otis Elevators alarm response centre of Farmington, Connecticut, which dealt with trapped passengers - it took about 20 minutes to rescue people; the Otis Test Tower, at Bristol in Connecticut, which had 29 floors and 11 lifts; architect Ken Yeang of Malaysia, known for his tall buildings; Gary Faltin of Otis; in the distant past, due to ropes, only goods were carried by lifts; in 1853 Elisha Otis invented a safety system for lifts, via a governor cable; only once have steel lift cables snapped, on 28 July 1945, in the 1945 Empire State Building B-25 crash after being lost in fog, severing the lift governor cable; if the cable snapped, due to the lift being balanced only after about nine people were in a lift, the lift would go upwards; on 12 August 1995, in the Empire State Building, a lift did go upwards, to be trapped at the 80th floor; the Woolworth Building, with 57 floors and 26 lifts, which could travel up to 10 mph - it was the world's tallest building from 1911 to 1930; engineer William Sheeran of Otis; medical doctor Rollin Stott, of the Linear Motion Laboratory of the Defence Research Agency (DERA) Centre for Human Sciences in north-east Hampshire; the feelings in the stomach, often sensed in a lift, comes from a pulse of adrenaline; Convent of Sacred Heart, with six floors; Nicole Fenchel was phobic of lifts; Doreen Powell of White Plains Hospital; the express lift, for the observation platform, in Tower 2 of the former World Trade Center had a journey time of 58 seconds; the former WTC had the world's second and third tallest office buildings; Tower 1 had 110 floors, being 417 metres high, with 96 lifts that could travel up to 15 mph; 70,000 people worked in the former WTC; people should not have to wait for a lift for no more than 30 seconds; Roger Howkins of Arup in London; 200 Vesey Street, known as Three World Financial Center, with 51 floors and 39 lifts, that could travel up to 14 mph; the former WTC was the first building to introduce the sky lobby design, with interspersed lifts; Robert DiChiara, assistant director of the former WTC; engineer Bruce Powell of Otis; Argentine architect, César Pelli, who designed One Canada Square of Canary Wharf; control systems of lifts anticipated demand; but there was a dark and menacing side to travel by lifts - Detectives Kevin Dineen and Lisa McClean of the NYPD Elevator Squad, at Carver Houses in the East Village, Manhattan, and how criminals could isolate victims; local youths and children would travel on top of the elevators for momentary thrills; the New York Marriott Marquis hotel, with 49 floors and 12 elevators, which could travel up to 15 mph; the Petronas Towers in Malaysia, with 88 floors, and 76 lifts, that could travel up to 16 mph, to be completed by 1997; lift ropes could go up to 600 metres, at the extreme most; new lifts would be powered by tubular linear motors or AC induction motors; 600 lifts with these new motors were operating in Japan; Yebisu Garden Place in Ebisu, Shibuya in Tokyo, where linear motors powered the lift counterweight; the Nishi-Shinjuku district in Shinjuku, Tokyo; many tall buildings were being built in Japan; Riverside Sumida Center, of Tokyo, built in 1994; the Yokohama Landmark Tower, with 70 floors, in Japan, built in 1993; Mitsubishi Electric had the world's fastest lifts, up to 28 mph; Junichi Sato of Mitsubishi, who said that he thought that Japanese people valued well-made products, and only trusted manufacturers too, whereas he thought that Americans and Europeans merely wanted functional products, whether good or not; the proposed enormous 800 metre Millennium Tower (Tokyo) for Tokyo Bay, with 150 floors, which was never built, but the Gherkin (30 St Mary Axe) was built instead; architect Andrew Miller of Foster Asia; there were twenty buildings over 60 floors being built; the Chinese economy was growing by 15% per year, and was Mitsubishi's biggest customer; the Century Tower (Tokyo), built in 1991, with 21 floors, with 14 lifts, that could travel up to 11 mph; lift technology had allowed Western business to prosper, but now it was superfluous for Western business. Narrated by Paul McGann, produced by Elizabeth Allen, directed by Gary Johnstone, made by Diverse Productions 22 October DNA in the Dock, an Equinox Special that was an update on the Incredible Evidence episode on 28 December 1994; The murder of 15-year-old Claire Hood, last seen on 19 January 1995, where 2,100 men had their DNA tested; her body was found in Cath Cobb Woods the next day; Sir Alec Jeffreys claimed that he could tell anyone apart; Timothy Wilson Spencer was the first person to be executed, with DNA evidence, on 27 April 1994, having committed murder in 1988; DCI Stuart Lewis, who worked on the Claire Hood investigation, who believed that her killer lived nearby - her killer lived 100 yards away; the United Kingdom National DNA Database began earlier in 1995, and in six months, 60,000 DNA specimens were recorded, and the database was intended to have 5 million specimens; an investigation of Orchid Cellmark, part of ICI, found that errors in correlation of specimens were made; California police gave test specimens to Cellmark, and errors were found, which Cellmark attributed to cross-contamination; Donald Findlay and a Scottish rape investigation in Largs, North Ayrshire, in 1987; former policeman Brian Kelly, and his wrongful conviction, for six years, serving four of them, for rape on 30 November 1989, through DNA evidence alone - DNA testing would later change in 1990, where crime scene DNA specimens were kept apart; Kary Mullis, who invented the PCR test in 1983, receiving the 1993 Nobel Prize in Chemistry, and knew about errors in DNA genetic testing; David Werrett of the Forensic Science Service, who set up the UK national DNA database in Birmingham, which deployed the PCR method - the more reliable Second Generation Multiplex Plus would be later introduced in 1999; Don Dovaston, later the deputy chief of Derbyshire Constabulary, which was the first police force to identify suspects through the UK DNA database; the Metropolitan Police had its own DNA database; Larry Mueller, population geneticist at the UCI School of Biological Sciences. Produced by David Poyser, directed by Hilary Lawson, made by TVF 5 November Kaboom!, the explosives engineer Sidney Alford; Controlled Demolition, Inc., founded by Jack Loizeaux; Rev Ron Lancaster, originally from Huddersfield, who founded Kimbolton Fireworks in 1964, when a chemistry teacher at Kimbolton School; in 1847 Ascanio Sobrero of Italy discovered nitroglycerin - nitroglycerin is the main component of dynamite; a detonation occurs at supersonic speed; Semtex was developed in Czechoslovakia in the 1960s; Ballistite, made from nitroglycerin and discovered in 1887, is the propellant for guns. Joint-production with NOVA and WGBH. Shown on Nova on 14 January 1997 12 November Avalanche, avalanches kill around two hundred people a year, with 120 of those in the Alps; Swiss physicist Othmar Buser of the Swiss Federal Institute for Forest, Snow and Landscape Research (WSL), who developed a database of avalanches; Bruce Tremper; Doug Fesler; powder snow avalanches can reach 150 mph; Laurent Buisson. Narrated by Heather Couper, made by Pioneer Productions with Discovery Networks 19 November God only Knows, about how some physicists see theology being explained through physics, such as Frank J. Tipler of Tulane University and his book The Physics of Immortality; George Johnson (writer) and book titles; Lewis Wolpert and how there was no evidence for God in the external world; David Finley of the National Radio Astronomy Observatory; religious writer Karen Armstrong, author of A History of God; Brazilian physicist Marcelo Gleiser; physicist Leon M. Lederman; Russell Stannard and physics before the big bang; the KTeV experiment at Fermilab, which looked at kaons, and Vivian O'Dell; Rev John Polkinghorne, former professor of Mathematical Physics at the University of Cambridge. Narrated by Bill Paterson, produced by Nicolas Kent, directed by Peter Webber 26 November Gloria's Toxic Death, about the death of Gloria Ramirez in California on 19 February 1994; a nurse, who took a blood sample from her, passed out from inhaling an unknown vapour coming from the blood sample; few episodes of Doctor Who had such a bizarre and unbelievable storyline; blood tests from the nurses revealed a lowering of the enzyme cholinesterase, which in other cases is linked to organophosphate poisoning; the Lawrence Livermore National Laboratory proposed a connection to dimethyl sulfoxide (DMSO) that had combined with oxygen given in the hospital to make dimethyl sulfate; the conditions of the hospital were repeated in a test, and the results underwent gas chromatography–mass spectrometry by Yolanda de Miguel at Department of Chemistry, Imperial College London. Narrated by Neil Pearson, directed by Tim Shawcross, produced by Geoff Deehan, made by Union Pictures with Discovery Communications 3 December On Jupiter, about the large gravitational effect that Jupiter has on the solar system; if the mass of Jupiter was thirty times bigger, the heat in its centre could sustain nuclear reactions, and it could become a star, maybe a brown dwarf; Gene Shoemaker of the Lowell Observatory and Palomar Observatory; Galileo Galilei discovered Jupiter's moons, Io, Europa, Ganymede (the largest moon in the solar system), and Callisto, on 7 January 1610; Heidi Hammel of MIT; Galileo (spacecraft), built at JPL and Ames in the 1980s, being planned to have launched in 1982, arrived at Jupiter on 7 December 1995; Torrence Johnson of JPL; Jim Scotti of the Spacewatch project at Kitt Peak National Observatory; Brian G. Marsden of the Central Bureau for Astronomical Telegrams; Vicki Meadows of the Anglo-Australian Telescope; Imke de Pater of the W. M. Keck Observatory on Mauna Kea; David Morrison (astrophysicist) of NASA Ames. Narrated by John Hurt, directed by Richard Smith, made by Pioneer Productions and the Discovery Channel 10 December Designing Dream Machines, about product innovation and product design of food processors and a reinvented motorbike by the Seymour-Powell design agency and its designer Nick Talbot, with the management team of Tefal UK and its managing director and a design by 43-year-old Dick Powell, and a possible new design of the ubiquitous 125CC BSA Bantam motorbike for MZ Motorrad- und Zweiradwerk of Germany by 42-year-old Richard Seymour; the 59 Club; Leigh Martin of the defunct Comet (closed in December 2012). Narrated by Marilyn Milgrom, directed by Richard Burke, produced by Richard Reisz. TV6 went on to make the six-part series Better by Design 17 December It Runs on Water, about the field commonly known as fringe science, where physicist Frank Close was sceptical if not broadly dismissive, stating that 300 years of science could not be overruled, but a professor of Aeronautics Paul Csysz of Saint Louis University mentioned that he thought some people in science were often unquestioning of their lifelong-held beliefs, and nervous of anyone trying to do so; an invention in Moscow was looked at by American physicist Harold E. Puthoff; Stanley Meyer's water fuel cell; NASA's propulsion research at Lewis Research Center in Cleveland, Ohio; it ends with Sir Arthur C. Clarke and Requiem (Mozart). Directed by Lawrence Simanowitz, produced and narrated by William Woollard, made by InCA Productions with Discovery Communications 20 December Do Vampire Bats have Friends?, an Equinox Special about whether animals have consciousness; zoologist Prof John Krebs, Baron Krebs, and whether animals had human-like sentience; biologist Gerald Wilkinson of the University of Maryland, and research, over five years, into relationships of vampire bats with other types of animals, and found food sharing between hungry vampire bats; zoologist Miriam Rothschild; psychologist Cecilia Heyes of UCL and self-perception of chimpanzees; zoologist Bernd Heinrich of the University of Vermont, and puzzle-solving of raven birds; zoologist Benjamin Beck of The National Zoo, and the apparent deployment of tools by animals; Ian Farquhar, and foxhunting, and whether foxes realise their predicament, and the Duke of Beaufort's Hunt in Gloucestershire; biologist Sir Patrick Bateson of the University of Cambridge, sensation of pain in animals, and the Animals (Scientific Procedures) Act 1986, which defined protected animals, that did not cover the octopus, but due to research by the Universities Federation for Animal Welfare (UFAW); Prof Peter Boyle and Martin Wells, and a 1993 amendment added the octopus; Prof Daniel Dennett of Tufts University, and how snakes think; psychologist Irene Pepper berg, of the University of Arizona, and an African Grey parrot called Alex, who has been talking for 18 years; the horse Clever Hans; Robert Seyfarth (scientist) and Dorothy Cheney (scientist), and their work on baboon warning calls and grunts, in Kenya. Narrated by Andrew Sachs, directed by Christopher Sykes, made by Christopher Sykes Productions
Sources: en.wikipedia.org
DCI John Caldwell, an off duty Police Service of Northern Ireland officer, is injured in Omagh after being shot by suspected New IRA gunman. 23 February Labour leader Sir Keir Starmer outlines the five key issues that his party will focus on during the run up to the 2024 general election: higher economic growth, clean energy, improving the NHS, reforming the justice system, and raising education standards. Environment Secretary Thérèse Coffey, commenting on the vegetable shortage, tells MPs "we anticipate the situation will last about another two to four weeks". Three men are arrested in relation to the previous evening's shooting of DCI John Caldwell. 24 February The British Medical Association announces that junior doctors in England will begin a three-day strike on 13 March. An earthquake measuring 3.7 magnitude strikes Brynmawr, Blaenau Gwent at 11.59pm. COVID-19 in the UK: Office for National Statistics data for the week up to 14 February indicates COVID-19 cases continued to rise in England, Scotland and Wales, but remained uncertain in Northern Ireland. In England, the estimated number of people testing positive for COVID-19 was 1,223,000 (or 2.18% of the population and around 1 in 45 people). 27 February New Transgender Policy Guidance for England and Wales came into force on 27 February 2023 under which transgender women offenders would no longer be housed in women's prisons if they had male genitalia or had committed sex crimes.
== Applications to cryptography == The difficulty of protein sequencing was recently proposed as a basis for creating k-time programs, programs that run exactly k times before self-destructing. Such a thing is impossible to build purely in software because all software is inherently clonable an unlimited number of times.
===== Domestic electrical installation ===== Ground fault interrupters are available to reduce electric fields and (in the case of current flow) magnetic fields from residential electrical installations. In plaster installations, only a small part of the electric field can escape from the wall. However, a mains disconnect switch automatically disconnects the relevant line as long as no electrical load is switched on; as soon as a load is switched on, the mains voltage is also switched on. Ground fault interrupters were introduced in 1973 and have been continuously improved over the decades. In 1990, for example, it became possible to disconnect the PEN conductor (formerly known as the neutral conductor). Circuit breakers can be installed in several different circuits, preferably in those that supply bedrooms. However, they only turn off when no continuous current consumers such as air conditioners, fans, humidifiers, electric alarm clocks, night lights, standby devices, alarm systems, chargers, and similar devices are turned on. Instead of the mains voltage, a low voltage (2-12 volts) is applied, which can be used to detect when a consumer is switched on. Rooms can also be shielded with copper wallpaper or special wall paints containing metal, thus applying the Faraday cage principle.
Sources: en.wikipedia.org
不存在。它是依据 ACTH 的一段序列人工设计的分子，天然蛋白质中找不到与之完全相同的七肽。名称属于研究代号，而非天然物质名。
Semax 对应 ACTH 第 4 至第 10 位的片段，并在两端做了替换与延长，使其不再具备促肾上腺皮质激素的典型内分泌活性。这一改动同时改变了它在体内的稳定性与分布特征。
俄罗斯将其列为处方药物，需要医生开具处方。多数其他国家把它当作研究化合物，不能作为药品销售或宣称疗效。具体合法性取决于当地法规。
Reversed-phase HPLC gives the main purity figure, most often with UV detection near 214 nanometres. Mass spectrometry then confirms the molecular mass. Together the two methods distinguish a correct sequence from a closely related impurity.