If you have been reading about counterion and want a single page that covers the useful parts, this is it: definitions, context, how it is studied, and the questions that come up repeatedly.
Last reviewed on 2025-12-28. Where a claim depends on a specific study, the study is described rather than over-claimed.
Scientific literature on semax is unevenly distributed. A substantial share of published work originates from a small number of laboratories in Russia, while independent replication elsewhere is limited. Human data consist mostly of small trials with short follow-up, and several reported outcomes rely on subjective rating scales. Questions about how much intact peptide reaches the central nervous system after nasal administration, and how long it persists there, are still unresolved. The compound is best described as an active research subject rather than a settled pharmacological agent.
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.
常规纯度与身份确认依赖反相高效液相色谱，并辅以质谱测定分子量。氨基酸组成分析可用于验证序列构成，肽图分析则能进一步定位修饰或降解产物。杂质谱通常关注缺失序列肽、截短片段和氧化产物。不同方法的检出限并不相同，因此各实验室报告的纯度数值不宜直接横向比较。
多数实验室与市售的 Semax 以冻干粉形式提供。冻干粉通常建议保存在 -20 °C 或更低温度下，同时避免光照与反复升温。短期运输有时采用冷藏条件，但长期保存仍以冷冻为主。分包操作应尽量减少开盖次数，以降低吸湿和微生物污染的风险。开封后若未一次用完，建议在干燥环境中密封并尽快放回低温储存。
| Property | Value | Notes |
|---|---|---|
| Molecular formula | C37H51N9O10S | Calculated for the free peptide |
| Molar mass | 813.9 g/mol | Anhydrous free base |
| Peptide class | Synthetic heptapeptide | ACTH(4-10) analogue |
| Parent fragment | ACTH(4-10) | Adrenocorticotropic hormone segment |
| Developmental origin | Institute of Molecular Genetics, Moscow | Work began in the 1980s |
该化合物于二十世纪八十年代在俄罗斯被开发，相关工作由俄罗斯科学院分子遗传学研究所的研究团队主导。开发目标并非复制 ACTH 的完整激素活性，而是寻找保留其神经作用方向、同时去除促肾上腺皮质激素释放效应的短肽片段。研究记录显示，这一方向促成了多个相关短肽的合成与筛选，而 Semax 是其中被研究最广泛的一个。当地文献常以 Семакс 这一名称指代它。
研究兴趣主要集中在神经营养因子相关的路径上，包括脑源性神经营养因子与神经生长因子的表达变化。部分实验报告称在特定条件下观察到这些因子的水平上升，但具体信号通路和剂量依赖关系仍未完全厘清。多数公开数据来自细胞模型和动物实验，人体对照研究数量有限。因此，该化合物的作用机制在文献中属于活跃讨论，而非已经确立的定论。
Semax 是一种人工合成的七肽，氨基酸序列为 Met-Glu-His-Phe-Pro-Gly-Pro，单字母缩写记作 MEHFPGP。它被归类为促肾上腺皮质激素片段 ACTH(4-10) 的结构类似物，但并不天然存在于生物体内。母体片段 ACTH(4-10) 的序列为 Met-Glu-His-Phe-Arg-Trp-Gly，Semax 替换了中间两个残基，并在羧基端延长了 Pro-Gly-Pro 三肽。这种延长被普遍认为能提升分子对肽酶的耐受性。
Quality documentation for research-grade peptide usually includes a certificate of analysis stating purity, identity, and residual counterion content. Batch-to-batch variation in purity and salt form is a recognized issue, and comparisons across suppliers require attention to the exact counterion, for example acetate versus trifluoroacetate. Sequence verification by tandem mass spectrometry provides stronger evidence than a single mass measurement. For any study reporting biological results, the analytical method and the measured purity should be stated explicitly. Independent verification of supplier claims is considered good practice.
Semax is supplied as a lyophilized powder that appears white to off-white. It dissolves readily in water, phosphate-buffered saline, and other aqueous media, which simplifies preparation of working solutions for laboratory use. The nasal products registered in Russia are dilute aqueous solutions, typically around 0.1 percent peptide by weight. Organic solvents are rarely necessary and can complicate handling. Because the peptide is hygroscopic, weighing should be performed quickly and with minimal exposure to ambient humidity.
== Further reading == "Bernie Sanders Explains... Why Americans Are Furious at the Democrats: The Nation Interview [by John Nichols]", The Nation, vol. 321, no. 4 (November 2025), pp. 30–34. "[T]he [Democratic] party is saying, '[W]e can't support [Zohran Mamdani, running for New York City mayor] because he is saying what 75 percent of Democrats say about Israel: No more money for Netanyahu.' [p. 32.] [T]he money people decide who the candidates are... [p. 33.] A few years ago ... a poll [showed that] [a]lmost 60 percent of the people said [they] were better off 50 years ago. [p. 34.]" Chiasson, Dan (2026). Bernie for Burlington: The Rise of the People's Politician. New York: Knopf. ISBN 978-0-59331-749-5. Rall, Ted (2016). Bernie. New York: Hollowbrook Publishing. ISBN 978-1-60980-698-9. Rice, Tom W. (1985). "Who Votes for a Socialist Mayor?: The Case of Burlington, Vermont". Polity. 17 (4): 795–806. doi:10.2307/3234575. ISSN 0032-3497. JSTOR 3234575. OCLC 5546248357. S2CID 153889856. Rosenfeld, Steven (1992). Making History in Vermont: The Election of a Socialist to Congress. Wakefield, NH: Hollowbrook Publishing. ISBN 978-0-89341-698-0. LCCN 91034055. OCLC 24468446. OL 1553980M. Soifer, Steven (1991). The Socialist Mayor: Bernard Sanders in Burlington, Vermont. Westport, CN: Praeger. ISBN 978-0-89789-219-3. LCCN 90048954. OCLC 22491683. OL 1887682M.
== Properties == Ammonium sulfate becomes ferroelectric at temperatures below −49.5 °C (−57.1 °F). At room temperature it crystallises in the orthorhombic system, with cell sizes of a = 7.729 Å, b = 10.560 Å, c = 5.951 Å. When chilled into the ferrorelectric state, the symmetry of the crystal changes to space group Pna21.
=== Acid === Formic acid shares most of the chemical properties of other carboxylic acids. Because of its high acidity, solutions in alcohols form esters spontaneously; in Fischer esterifications of formic acid, it self-catalyzes the reaction and no additional acid catalyst is needed. Formic acid is unique in its ability to participate in addition reactions with alkenes. Formic acids and alkenes readily react to form formate esters. In the presence of certain acids, including sulfuric and hydrofluoric acids, however, a variant of the Koch reaction occurs instead, and formic acid adds to the alkene to produce a larger carboxylic acid. Formic acid is a source for a formyl group for example in the formylation of N-methylaniline to N-methylformanilide in toluene.
With the encouragement of Ollendorff (promising that a US organization called "The Friends of the Technion" would support Feher's studies), he applied for 50 universities in the US, and only two were willing to accept him. He could not afford the voyage to US so he started a small production line for devices with piezoelectric crystals, mainly microphones. In December 1946 he arrived to New York, where he realized that "Friends of the Technion" would not fund his degree. With poor means he attended the University of California, Berkeley, where he received his bachelor's degree in engineering physics (1950), master's degree in electrical engineering (1951) and doctorate (1954).
== Further reading == Paradise for Sale: A Parable of Nature. McDaniel and Gowdy. "Christmas Island". Fact sheet 157. National Archives of Australia. 2013. Archived from the original on 4 February 2014. Retrieved 18 January 2014. Weeramantry C. Nauru: environmental damage under international trusteeship. Melbourne: Oxford University Press; 1992. Williams M, Macdonald BK. The phosphateers: a history of the British Phosphate Commissioners and the Christmas Island Phosphate Commission. Carlton, Vic: Melbourne University Press; 1985. Albert Fuller Ellis 1935. Ocean Island and Nauru – their story. Angus and Robertson Limited
Sources: en.wikipedia.org
Ashutosh Chilkoti is an Indian American biomedical engineer, academic, researcher and serial entrepreneur. He is the Alan L. Kaganov Professor of Biomedical Engineering in the Pratt School of Engineering at Duke University. Chilkoti has published over 350 papers, has been cited 48,000 times, has a Google Scholar H-index of 116 and has 62 US patents awarded. His research is focused on genetically encoded materials and biointerface science and he has pioneered the development of high-throughput and scalable methods for the recombinant synthesis of repetitive polypeptides, invented a method to purify protein drugs without chromatography, and developed a technology for point-of-care clinical diagnostics. He has founded five start-up companies, including PhaseBio Pharmaceuticals in 2002, Sentilus in 2011, Gateway Bio in 2017, Isolere Bio in 2018, and inSoma Bio in 2019. Chilkoti is a Fellow of American Association for the Advancement of Science, National Academy of Inventors, Biomedical Engineering Society, Controlled Release Society, International Union of Societies for Biomaterials Science and Engineering and American Institute for Medical and Biological Engineering (AIMBE).
=== Multiple Reaction Monitoring (MRM) === Although MRM has been used extensively in metabolomics and proteomics, its high sensitivity and linear response over a wide dynamic range make it especially suited for glycan biomarker research and discovery. MRM is performed on a triple quadrupole (QqQ) instrument, which is set to detect a predetermined precursor ion in the first quadrupole, a fragmented in the collision quadrupole, and a predetermined fragment ion in the third quadrupole. It is a non-scanning technique, wherein each transition is detected individually and the detection of multiple transitions occurs concurrently in duty cycles. This technique is being used to characterize the immune glycome. Table 1:Advantages and disadvantages of mass spectrometry in glycan analysis
10 November Dead Men Talk, new dating techniques reveal more about the evolution of man, found from the Skhul and Qafzeh hominins at the Qafzeh cave, and future DNA sequencing methods could reveal from bones how man evolved, it featured Milford H. Wolpoff and Chris Stringer, being similar to the September 1996 edition about Neanderthals; a cave object was thought to be 40,000 years ago, but now was thought to be 100,000 years old; there were two paradigms, one where everyone is from Homo Erectus, and the other where Homo Sapiens evolved exclusively in Africa from Homo Erectus; this theory was from evidence at Border Cave in South Africa, Omo Kibish Formation in Ethiopia, and the Skhul cave; Milford Wolpoff, of the University of Michigan, supported the first multi-regional model; the second Eve theory came from Chris Stringer of the Natural History Museum, who looked at a fossil at Jebel Irhoud, Morocco; new dating techniques were electron spin resonance dating (ESR), deployed by Dr Rainer Grün at the Godwin Laboratory, University of Cambridge, and thermoluminescence dating (TL) which looked at flints that had been heated in primitive fires; a Neanderthal at Kebara Cave was dated at 60,000, with the new dating technique; the two caves, Skhul had homo sapiens, and Tanum Cave had Neanderthals, nearby; Chris Stringer thought that the Neanderthals split 300,000 years ago; the Neanderthal found at Amud Cave had a large brain; Joel Rak of Tel Aviv University believed that Neanderthals were a separate species; geneticist Rebecca L.
=== Caenorhabditis elegans === Fic-1 is the only Fic protein present in the genetic code of C. elegans. It is primarily found in the ER nuclear envelope of adult germline cells and embryotic cells, but small amounts may be found within the cytoplasm. This extra-ER pool of FICD-1s is credited with AMPylation of core histones and eEF1-A type translation factors within the nematode. Though varying AMPylation levels did not create any noticeable effects within the nematode's behaviour or physiology, Fic-1 knockout worms were more susceptible to infection by Pseudomonas aeruginosa compared to the counterparts with active Fic-1 domains, implying a link between AMPylation of cellular targets and immune responses within nematodes.
Sources: en.wikipedia.org
DiCaprio was an executive producer on Virunga, a 2014 British documentary film about four people fighting to protect the world's last mountain gorillas from war and poaching. The film premiered at the Tribeca Film Festival in April 2014, and DiCaprio was nominated for the 2015 Primetime Emmy Award for Outstanding Documentary or Nonfiction Special. Cowspiracy: The Sustainability Secret was another documentary film that year for which he was an executive producer—he took part in the new cut released exclusively on Netflix that September. It explores the impact of animal agriculture on the environment. DiCaprio is a patron of The Gorilla Organization, a UK-based charity continuing Dian Fossey's work to protect gorillas in the Virungas. In 2015, DiCaprio produced and played fur trapper Hugh Glass in Alejandro G. Iñárritu's survival drama The Revenant. DiCaprio found his role in the film difficult; he had to eat a raw slab of bison's liver and sleep in animal carcasses. He also learned to shoot a musket, build a fire, speak two Native American languages (Pawnee and Arikara) and apply ancient healing techniques. Built on a budget of $135 million, the film earned $533 million worldwide. The film received positive reviews with particular praise for DiCaprio's acting. Mark Kermode of The Guardian wrote that DiCaprio shone with a performance that prioritizes physicality over speech, and Nick De Semlyen of Empire noted that he uplifted the film. The film earned him numerous awards, including the Academy Award, BAFTA, Critics' Choice, Golden Globe and SAG Award for Best Actor.
With no further compression, the nerves will remyelinate and fully recover. Severe carpal tunnel syndrome patients may have degree II/III injuries (Sunderland classification), or axonotmesis, where the axon is injured partially or fully. With axon injury, there would be muscle weakness or atrophy, and with no further compression, the nerves may only partially recover. While there is evidence that chronic compression is a major cause of carpal tunnel syndrome, it may not be the only cause. Nerve scarring (specifically adherence between the mesoneurium and epineureum) may prevent the nerve from gliding during wrist or finger movements, causing repetitive traction injuries. Another is the double crush syndrome, where compression may interfere with axonal transport, and two separate points of compression (e.g. neck and wrist), neither enough to cause local demyelination, may together impair normal nerve function.
It is estimated that for acetamide, structure A makes a 62% contribution to the structure, while structure B makes a 28% contribution (these figures do not sum to 100% because there are additional less-important resonance forms that are not depicted above). Resonance is largely prevented in the very strained quinuclidone. In their IR spectra, amides exhibit a moderately intense νCO band near 1650 cm−1. The energy of this band is about 60 cm−1 lower than for the νCO of esters and ketones. This difference reflects the contribution of the zwitterionic resonance structure.
=== Optical iridectomy === Optical iridectomy creates a clear entrance pupil, improving vision in patients with segmental corneal opacities. An area of clear peripheral cornea can produce retinal images compatible with good visual acuity.
=== Types === 2-keto compounds: clorazepate, diazepam, flurazepam, halazepam, prazepam, and others 3-hydroxy compounds: lorazepam, lormetazepam, oxazepam, temazepam 7-nitro compounds: clonazepam, flunitrazepam, nimetazepam, nitrazepam Triazolo compounds: adinazolam, alprazolam, estazolam, triazolam Imidazo compounds: climazolam, loprazolam, midazolam 1,5-benzodiazepines: clobazam
Sources: en.wikipedia.org
Semax is based on the ACTH(4-10) fragment, a seven-amino-acid segment of adrenocorticotropic hormone. The synthetic peptide retains the core sequence while removing regions associated with endocrine activity. This modification is intended to isolate effects on the nervous system.
It is registered for clinical use in Russia and a few other countries, typically as a nasal drop formulation. It does not hold approval from the United States Food and Drug Administration or the European Medicines Agency. Outside those markets it is generally handled as a research chemical.
The compound was developed in Moscow and the earliest studies were conducted there, so the primary literature is largely in Russian-language journals. Translation and indexing have been incomplete, which limits access for outside researchers. Independent groups have since published some work, but the total volume remains modest.
一般不建议常温长期保存。多数说明指向 -20 °C 冷冻避光。常温运输通常被视为短期可接受，但会加快降解风险。