This is a working overview of 肽纯度, written for readers who want more than a one-paragraph summary but less than a textbook.
Reviewed 2026-03-21. Anything still debated is marked as such rather than presented as settled.
Verification of a supplied batch generally combines a certificate of analysis with independent testing, because certificates are self-reported documents. A typical package includes a chromatographic trace, a mass spectrum, and a stated water or counter-ion content. Batch-to-batch consistency matters more than a single purity figure when results are compared across experiments. No single mandatory standard governs research-grade peptide release, so laboratories are expected to define their own acceptance criteria. Residual trifluoroacetate from purification is a frequently overlooked counter-ion.
Lyophilized material is chemically stable for extended periods when kept dry, cold, and protected from light. The powder is hygroscopic, so vials should be warmed to room temperature before opening to reduce condensation on the contents. Once dissolved, the peptide is far less stable because peptide bonds are susceptible to hydrolysis and the methionine residue can oxidize. Solutions are typically aliquoted and held at 2-8 °C for short intervals or frozen for longer ones, and repeated freeze-thaw cycles should be avoided.
Development took place during the 1980s at institutes of the Russian Academy of Sciences, where peptide fragments of ACTH were screened for cognitive and neuroprotective effects. The compound received regulatory approval in Russia as a nasal preparation, marketed for conditions such as ischemic stroke, transient ischemic attacks, and optic nerve disorders. Registration in other countries has not followed. Most published clinical reports originate from a small number of Russian research groups, and independent replication outside that setting remains limited. The regulatory status therefore differs sharply between Russia and the rest of the world.
Laboratory work points toward modulation of neurotrophic signaling, particularly expression of brain-derived neurotrophic factor and nerve growth factor in hippocampal tissue. Studies also describe effects on monoamine turnover, inflammatory mediators, and oxidative markers. These observations come mainly from animal models and cultured cells, so the causal chain in humans is not firmly established. Whether the reported molecular changes translate into measurable clinical benefit is an open question. Reviews generally present the mechanism as plausible rather than demonstrated.
| Property | Value | Notes |
|---|---|---|
| Typical purity | 95% or higher | By reversed-phase HPLC area |
| Identity method | Electrospray mass spectrometry | Confirms molecular mass |
| Purity method | Reversed-phase HPLC | Detection near 214 nm |
| Primary degradation | Methionine oxidation | Sulfoxide product, +16 Da |
| Solution storage | 2-8 °C, short term | Aliquot to avoid freeze-thaw |
Practical handling follows from those properties. Bulk material is best divided into single-use portions soon after receipt, because each thaw exposes the whole container to moisture and temperature cycling. Vials should be allowed to reach room temperature before opening to prevent condensation on the powder. Low-binding plasticware reduces loss of dilute solutions, and sterile filtration is used when a preparation must remain free of microbial growth. Records of batch number, reconstitution date and storage history are what allow a later analytical result to be interpreted meaningfully.
Identity and purity of Semax are established mainly by reversed-phase high-performance liquid chromatography coupled with mass spectrometry. The chromatographic trace gives a purity estimate as a percentage of total peak area, while electrospray or matrix-assisted laser desorption ionization confirms the molecular mass against the calculated value. Amino acid analysis and sequence-specific fragmentation provide further confirmation when a supplier's chain of custody is unclear. Vendors frequently quote a purity figure without stating the detection wavelength or the integration method, which limits how far one number can be compared with another.
Stability depends heavily on physical state. Lyophilized powder held dry, cold and dark retains its content over long periods, whereas dissolved peptide begins to change within days at room temperature. The most cited degradation route is oxidation of the methionine residue, which converts the peptide to a sulfoxide form that elutes differently on chromatography. Hydrolysis of amide bonds and adsorption onto container walls contribute smaller losses. Buffers that exclude oxygen from the headspace slow the oxidation pathway, but no single condition prevents all change indefinitely.
The parent fragment ACTH(4-10) carries the sequence Met-Glu-His-Phe-Arg-Trp-Gly. Semax replaces the arginine and tryptophan positions with a proline-glycine-proline tail, giving Met-Glu-His-Phe-Pro-Gly-Pro. That change removes residues associated with adrenal stimulation, so the peptide does not drive cortisol release the way full ACTH does. This distinction shapes how the compound is grouped in the literature, where it sits with neuropeptides and peptide neuromodulators rather than with corticosteroids.
Regulatory status varies sharply by country. Semax is registered for medical use in Russia, where it appears in formularies as a nasal solution, and it also holds registration in a small number of neighbouring states. It has no approval from the United States Food and Drug Administration or the European Medicines Agency, and it is not a scheduled controlled substance in most jurisdictions. Elsewhere it circulates mainly as laboratory material, so purity documentation comes from suppliers rather than from a national pharmacopoeia.
Semax is a synthetic peptide created in the Soviet Union during the early 1980s by researchers working in Moscow. It was built from the short adrenocorticotropic hormone fragment known as ACTH(4-10), and the chain was then extended with three additional amino acids. The resulting molecule was named semax and entered clinical use in Russia in 1994. It is generally described as a nootropic and neuroprotective agent rather than as a hormone analogue.
从分子层面看，Semax 是线性七肽，没有二硫键、糖基或脂链修饰，N 端为游离氨基，C 端为游离羧基。分子含组氨酸与谷氨酸侧链，因此在水和甲醇等极性溶剂中溶解良好，在非极性溶剂中溶解有限。计算分子量约为 814 Da，与其质子化离子的质荷比吻合，可用于质谱确认。
稳定性主要由水解与氧化两条路径支配。肽键在中性或弱酸性条件下相对稳定，遇到强碱或长时间高温则明显断裂；甲硫氨酸侧链容易被氧化成亚砜，使主峰前移并拉低实际含量。金属离子、光照和反复冻融会进一步促进降解或聚集。冻干粉在低温避光条件下可存放较长时间，配制后的水溶液通常需要冷藏并尽快用完。
Clinical reports describe use in ischaemic stroke, transient ischaemic attack, optic nerve conditions, and cognitive complaints, but most of these studies are small and were conducted in a single region. Systematic reviews have generally described the evidence base as limited in size and variable in methodological quality. Randomised controlled data suitable for international regulatory assessment are scarce. As a result, major treatment guidelines outside Russia do not include the peptide, and interest in it remains largely research-driven rather than routine clinical.
Semax is a synthetic heptapeptide with the sequence Met-Glu-His-Phe-Pro-Gly-Pro. It is described in the literature as an analogue of the ACTH(4–10) fragment, a short N-terminal portion of adrenocorticotropic hormone that retains some neurotropic activity without the full hormonal effects of the parent peptide. The molecule carries a methionine residue at the N-terminus and two proline residues near the C-terminus, features that shape both its interactions with receptor systems and its chemical stability. The free peptide corresponds to the formula C37H51N9O10S and a molecular mass near 813.9 Da.
The compound was developed in the 1980s at the Institute of Molecular Genetics in Moscow, where it emerged from research on short ACTH fragments and their effects on the central nervous system. Russian pharmaceutical listings describe it as a nootropic and neuroprotective agent, most often formulated as nasal drops. It is not a marketed medicine in the United States or the European Union, and no pharmacopoeial monograph covers it. Consequently, most published clinical experience with the substance originates from a small number of research centres, mainly in Russia and neighbouring countries.
"Le minutier central des notaires de Paris aux Archives nationales" [The central minute book of Paris notaries at the National Archives] (in French). Archived from the original on May 28, 2013. "Base Léonore, le fonds de la Légion d'honneur aux Archives nationales" [Base Léonore, the Legion of Honor collection at the French National Archives] (in French). Archived from the original on May 14, 2013. Dictionnaire critique de biographie et d'histoire [Critical Dictionary of Biography and History] (in French). 1872. Archived from the original on July 21, 2015. (where the author, Auguste Jal, transcribed numerous birth, baptism, marriage, death and burial certificates of historical and famous personalities before they were destroyed in 1871). Notes prises aux archives de l'état-civil de Paris [Notes taken from the Paris registry office archives] (in French). 1875. Archived from the original on January 1, 2022. Piot, Eugène (1873). "État civil de quelques artistes français" [Marital status of some French artists] (in French). Paris Pagnerre. "Projet Familles Parisiennes" [Parisian Families Project] (in French). Archived from the original on January 1, 2022. "La vie des Parisiens du XIXe siècle se met à revivre !" [Nineteenth-century Parisians come to life!] (in French). Archived from the original on January 18, 2022. Vanwelkenhuyzen, Michel.
Studies suggest that light pollution desynchronizes spawning in some coral species. In areas such as the Red Sea, as many as 10 out of 50 species may be showing spawning asynchrony, compared to 30 years ago. The establishment of new corals in the area has decreased and in some cases ceased. The area was previously considered a refuge for corals because mass bleaching events due to climate change had not been observed there. Coral restoration techniques for coral reef management are being developed to increase fertilization rates, larval development, and settlement of new corals.
Kopi luwak (Indonesian pronunciation: [ˈkopi ˈlu.aʔ]), also known as civet coffee, is a coffee that consists of partially digested coffee cherries, which have been eaten and defecated by the Asian palm civet (Paradoxurus hermaphroditus). The cherries are fermented as they pass through a civet's intestines, and after being defecated with other fecal matter, they are collected. Although kopi luwak is a form of processing rather than a variety of coffee, it is known as one of the most expensive coffees in the world, with retail prices reaching $100 per kilogram ($45/lb) for farmed beans and $1,000 per kilogram ($450/lb) for wild-collected beans. Another epithet for it is the "Holy Grail of coffees".
== Research == A wave of enthusiasm for secretin as a possible treatment for autism arose in the 1990s based on a hypothetical gut-brain connection; as a result the NIH ran a series of clinical trials that showed that secretin was not effective, which brought an end to popular interest. A high-affinity and optimized secretin receptor antagonist (Y10,c[E16,K20],I17,Cha22,R25)sec(6-27) has been designed and developed which has allowed the structural characterization of secreting inactive conformation.
exaggerated neuronal reflexes triggered by stimulation of irritant receptors on sensory nerve endings (such as exercise-induced asthma) release of preformed cytokines from several type of inflammatory cells (T cells, eosinophils) in allergen-induced asthma Note: Another chemical (NPPB: 5-nitro-2(3-phenyl) propylamino-benzoic acid) was shown, in the same study, to be a more effective chloride channel blocker. Finally it may act by inhibiting calcium influx. Cromoglicate is classified as a chromone. Cromolyn is also being tested as a drug to treat insulin-induced lipoatrophy and Alzheimer's disease in combination with Ibuprofen. Cromolyn is also known to bind S100P protein and disrupt the interaction with RAGE.
Sources: en.wikipedia.org
The target material is exposed an external source of radiation. The radiation source supplies energetic particles or electromagnetic waves. These particles or waves collide with material in the target. The higher the likelihood of these collisions over a distance are, the lower the penetration depth of the irradiation process is as the energy is more quickly depleted. These collisions break chemical bonds, creating short lived radicals (e.g. the hydroxyl radical, the hydrogen atom and solvated electrons). These radicals cause further chemical changes by bonding with and or stripping particles from nearby molecules. When collisions occur in cells, cell division is often suppressed, halting or slowing the processes that cause the food to mature. When the process damages DNA or RNA, effective reproduction becomes unlikely halting the population growth of viruses and organisms. The distribution of the dose of radiation varies from the food surface and the interior as it is absorbed as it moves through food and depends on the energy and density of the food and the type of radiation used.
== Honors and awards == Dyson was elected a Fellow of the Royal Society (FRS) in 1952. Dyson was elected to the American Academy of Arts and Sciences in 1958. Dyson was elected to the United States National Academy of Sciences in 1964. Dyson was awarded the Dannie Heineman Prize for Mathematical Physics in 1965, Lorentz Medal in 1966, Max Planck Medal in 1969, the J. Robert Oppenheimer Memorial Prize in 1970, the Harvey Prize in 1977 and Wolf Prize in 1981. Dyson was elected to the American Philosophical Society in 1976. In 1986, Dyson received the Golden Plate Award of the American Academy of Achievement. In 1989, Dyson was elected as an Honorary Fellow of Trinity College, University of Cambridge. In 1990, Dyson taught at Duke University as a Fritz London Memorial Lecturer. Dyson published a number of collections of speculations and observations about technology, science, and the future. In 1996, he was awarded the Lewis Thomas Prize for Writing about Science. In 1993, Dyson was given the Enrico Fermi Award. In 1995, he gave the Jerusalem-Harvard Lectures at the Hebrew University of Jerusalem, sponsored jointly by the Hebrew University and Harvard University Press that grew into the book Imagined Worlds. In 2000, Dyson was awarded the Templeton Prize for Progress in Religion. In 2003, Dyson was awarded the Telluride Tech Festival Award of Technology in Telluride, Colorado. In 2011, Dyson received as one of twenty distinguished Old Wykehamists at the Ad Portas celebration, the highest honor that Winchester College bestows. In 2011, Dyson received the Arthur C.
=== For diagnostics === The original goal for paper-based microfluidics (μPAD) was to make low-cost and user-friendly point-of-care (POC) devices that can be operated without the assistance of medical personnel or any other qualified specialist in resource-limited and rural areas. To achieve this goal, μPAD should fit the "Affordable, Sensitive, Specific, User-friendly, Rapid and robust, Equipment-free, Deliver" criteria, provided by the World Health Organization (WHO), which are the requirements for diagnostic testing for resource-constrained settings. However, in POC's official "Guide to aid the selection of diagnostic tests", it is stated that these criteria are generic and can be modified according to test application. The main problem of paper-based microfluidic diagnostics is that research in this field is directed on providing new concepts and ideas rather than on improving user acceptance and as a result, most μPAD devices are still unable to be interpreted by non-professional users. However, POC is not the only application of paper-based microfluidics for diagnostics. Recently, a paper was employed in the production of more complicated microfluidic analytical devices, called lab-on-a-chip (LOC) devices, which are also used in diagnostics. Using paper to make LOC devices instead of polydimethylsiloxane (PDMS) and glass can decrease cost and size while increasing portability. This allows LOC devices to become more accessible in resource-limited conditions.
Cricket in Hong Kong has been played since at least 1841. Like most cricketing nations, it was part of the British Empire. The national cricket team has been active since 1866, and the Hong Kong Cricket Association was granted associate membership of the International Cricket Council (ICC) in 1969. Hong Kong hosted the Hong Kong Cricket Sixes, an ICC-sanctioned event that features teams of six players in a six-over competition annually till 2012. The Hong Kong Cricket Team qualified for 2014 ICC World Twenty20 and caused a major upset by defeating hosts Bangladesh.
=== Incidence === Beta thalassemia is most prevalent in the "thalassemia belt" which includes areas in Sub-Saharan Africa, and the Mediterranean extending into the Middle East and Southeast Asia. This geographical distribution is thought to be due to the beta-thalassemia carrier state (beta-thalassemia minor) conferring resistance to malaria. In 2005, it was estimated that 1.5% of the world's population are carriers and 60,000 affected infants are born with the thalassemia major annually.
Sources: en.wikipedia.org
acetylation The covalent attachment of an acetyl group (–COCH3) to a chemical compound, protein, or other biomolecule via an esterification reaction with acetic acid, either spontaneously or by enzymatic catalysis. Acetylation plays important roles in several metabolic pathways and in histone modification. Contrast deacetylation.
In the United Kingdom, the democratic socialist tradition was represented by William Morris's Socialist League (founded 1884) and the Fabian Society (1885) and later the Independent Labour Party founded by Keir Hardie in the 1890s, of which writer George Orwell would later become a prominent member. The Fabian Society is a British socialist organisation which was established with the purpose of advancing the principles of socialism via gradualist and reformist means. The society functions primarily as a think tank and is one of the fifteen socialist societies affiliated with the Labour Party. Similar societies exist in Australia (the Australian Fabian Society), in Canada (the Douglas-Coldwell Foundation, and the since disbanded League for Social Reconstruction) and in New Zealand. The society laid many of the foundations of the Labour Party and subsequently affected the policies of states emerging from the decolonisation of the British Empire, most notably India and Singapore. Originally, the Fabian Society was committed to the establishment of a socialist economy, alongside a commitment to British imperialism and colonialism as a progressive and modernising force.
Sexual medicine is concerned with diagnosing, assessing and treating all disorders related to sexuality. Sports medicine deals with the treatment and prevention and rehabilitation of sports/exercise injuries such as muscle spasms, muscle tears, injuries to ligaments (ligament tears or ruptures) and their repair in athletes, amateur and professional. Therapeutics is the field, more commonly referenced in earlier periods of history, of the various remedies that can be used to treat disease and promote health. Travel medicine or emporiatrics deals with health problems of international travelers or travelers across highly different environments. Tropical medicine deals with the prevention and treatment of tropical diseases. It is studied separately in temperate climates where those diseases are quite unfamiliar to medical practitioners and their local clinical needs. Urgent care focuses on delivery of unscheduled, walk-in care outside of the hospital emergency department for injuries and illnesses that are not severe enough to require care in an emergency department. In some jurisdictions this function is combined with the emergency department. Veterinary medicine; veterinarians apply similar techniques as physicians to the care of non-human animals. Wilderness medicine entails the practice of medicine in the wild, where conventional medical facilities may not be available.
Poppy tea is a herbal tea infusion brewed from poppy straw or seeds of several species of poppy. The species most commonly used for this purpose is Papaver somniferum, which produces opium as a natural defense against predators. In the live flower, opium is released when the surface of the bulb, called the seed pod, is pierced or scraped. For the purpose of the tea, dried pods are more commonly used than the pods of the live flower. The walls of the dried pods contain opiate alkaloids, primarily consisting of morphine and codeine. The tea is consumed for its narcotic effect, and in small amounts for analgesic, anti-diarrheal, and sedative effects. It has also been known to be used as a method of relieving withdrawal symptoms. Use of such preparations originated in parts of Central and Eastern Europe, the Levant and Near East, and Central and South Central Asia millennia ago. The flowers of the poppy plant have long been used as a painkiller for soothing mild aches and pains (e.g. toothache, earache and sore throat), a mild sedative/relaxant, an expectorant for treating catarrh and coughs, as a digestive, and even for reducing the appearance of wrinkles and in lipsticks. This tea is depicted both in Asian literature, Western literature, and is depicted as being available in opium dens.
Sources: en.wikipedia.org
Dry powder is normally held at -20 °C or lower, away from light and moisture. Sealed vials can also be kept at 2-8 °C for shorter intervals. Warming to room temperature before opening prevents condensation.
In solution, hydrolysis of peptide bonds and oxidation of the methionine residue are the principal concerns. Oxidation converts methionine to its sulfoxide form, shifting the mass by sixteen daltons. Both processes are slowed by cold storage and by avoiding alkaline conditions.
A certificate documents what the supplier measured on a specific lot, not how a laboratory will use the material. Independent verification of identity and purity is common practice. Acceptance criteria should be defined before a batch is ordered.
Semax is a synthetic seven-amino-acid peptide derived from a fragment of corticotropin. It is used in Russia as a nasal preparation, while elsewhere it is studied as a research compound. It is not approved as a medicine in most countries.