If you have been reading about N-acetyl Semax 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 2026-07-03. Where a claim depends on a specific study, the study is described rather than over-claimed.
Purity assessment relies mainly on reversed-phase high-performance liquid chromatography, which separates the target heptapeptide from truncated sequences, deletion analogues, and oxidised forms. Mass spectrometry, usually coupled to liquid chromatography, confirms identity through the expected molecular ion and reveals modifications such as methionine sulfoxide formation. Amino acid analysis can verify composition, and tandem mass spectrometry supports sequence confirmation. Ultraviolet detection near 254 to 280 nanometres is convenient because the phenylalanine and histidine residues absorb in that region. Nuclear magnetic resonance is rarely used for routine release testing.
Common degradation pathways include oxidation of the methionine side chain, hydrolysis of the peptide backbone, and aggregation under unfavourable pH or concentration. Stability studies typically monitor the main peak by chromatography and report total related substances as a percentage. Because no official monograph exists, acceptance criteria vary between laboratories, and reported purity values are not directly comparable across suppliers. Analysts therefore document the method, column, and detection wavelength alongside each result, and open questions remain about how much biological activity the oxidised forms retain.
Solid semax is typically supplied as a lyophilised powder that is hygroscopic and sensitive to moisture, light, and repeated temperature cycling. Long-term storage of the dry peptide is generally recommended at approximately -20 degrees Celsius, while shorter working periods may use refrigeration at 2 to 8 degrees Celsius. Vials should remain tightly closed and desiccated when brought to room temperature, because condensation can damage the material before it is weighed. Dividing a batch into aliquots is preferable to thawing one container repeatedly.
溶液状态的稳定性明显低于冻干粉。肽类在水溶液中可能经历水解、氧化与聚集，其中甲硫氨酸和天冬酰胺等残基常是敏感位点。Semax 含有甲硫氨酸，因此氧化风险相对突出。工作液一般主张现配现用，或冷藏并在数日内用尽。缓冲液种类、pH 和离子强度都会影响降解速率，而关于最佳条件的公开数据并不统一。
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 |
|---|---|---|
| Typical analytical method | Reversed-phase HPLC with UV detection | Separates target peptide from truncated and oxidised forms |
| Identity confirmation | LC-MS or ESI-MS | Compares observed and calculated molecular ion |
| Primary degradation route | Methionine oxidation | Forms the sulfoxide; monitored as an early-eluting peak |
| Short-term storage | 2 to 8 degrees Celsius | Applies to working vials and reconstituted portions |
| Common synonyms | ACTH(4–10) analogue, MEHFPGP | Descriptive names used in laboratory catalogues |
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。
Semax binds to melanocortin receptors and is thought to influence neuronal survival and plasticity rather than to act through the adrenal axis. Laboratory work has shown increased expression of brain-derived neurotrophic factor and nerve growth factor in treated tissue. Changes in c-Fos, a marker of neuronal activation, have also been reported. Because the peptide is rapidly degraded by peptidases, its effects are generally attributed to downstream signaling cascades rather than to sustained receptor occupancy.
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.
This follows an exchange in the House during PMQs when Starmer, answering a question from the leader of the opposition, Kemi Badenoch, said that "two of her predecessors had convictions for breaking the Covid rules". Although the former Conservative prime ministers, Johnson and Rishi Sunak had received fixed penalty notices for breaking Covid-19 regulations, neither had any criminal convictions. Scottish Finance Secretary Shona Robison delivers the 2024 budget, which includes planned changes to taxation and a pledge to scrap the two child benefit cap in Scotland. Welsh Conservative leader Andrew RT Davies tells BBC News Wales there has been "plotting" among Conservative Senedd members to oust him since April. Secretary of State for Northern Ireland Hilary Benn begins the process of repealing the controversial Legacy Act. 27-year-old Sam Smith is announced as the new leader of Nottinghamshire County Council. Karen Kilgour, leader of Newcastle City Council, faces a vote of no confidence. 5 December – Starmer delivers a major speech in which he sets out six objectives which he says "give the British people the power to hold our feet to the fire"; the objectives cover the economy, housebuilding, the NHS, policing, pre-school education and green energy. Questions are raised over whether Henry Tufnell, the MP for Mid and South Pembrokeshire, gave his parents advanced knowledge of plans to change inheritance tax rules after they transferred ownership of farm land to one of their sons days before the budget.
National teams April 29 – May 1: 2018 FIBA 3x3 Asia Cup in Shenzhen Men: Australia defeated Mongolia, 17–16, in the final. Japan took third place. Women: New Zealand defeated China, 14–11, in the final. Australia took third place. August 5 – 11: 2018 FIBA Under-18 Asian Championship in Thailand In the final, Australia defeated New Zealand, 73–62, to win their 1st title. China took third place. Note: All teams mentioned here, plus Philippines, have qualified to compete at the 2019 FIBA Under-19 Basketball World Cup. October 28 – November 3: 2018 FIBA Under-18 Women's Asian Championship in Bangalore China defeated Japan, 89–76, to win their fifth consecutive and 16th overall FIBA Under-18 Women's Asian Championship title. Australia took third place. Note: All teams mentioned here, plus South Korea, have qualified to compete at the 2019 FIBA Under-19 Women's Basketball World Cup. Clubs teams November 17, 2017 – May 2: 2017–18 ABL season San Miguel Alab Pilipinas defeated Mono Vampire, 3–2 in games played in a 5-legged final, to win their first ABL title. July 17 – 22: Summer Super 8 in Macau Guangzhou Long-Lions defeated Seoul Samsung Thunders, 78–72, to win their first title. Incheon Electroland Elephants took third place.
Smith was hired to become the defensive quality control coach for the Tennessee Titans in 2011 under new head coach Mike Munchak. Smith then became the offensive quality coach the following season. In 2013, Smith was promoted to the assistant offensive line and assistant tight ends coach. Munchak was fired after the 2013 season and new head coach Ken Whisenhunt retained Smith as the assistant tight ends coach. Midway through the 2015 season, Whisenhunt was fired and replaced by tight ends coach Mike Mularkey. Mularkey was kept as head coach for the 2016 season and Smith was promoted to the new tight ends coach. When Mularkey was fired after the 2017 season, new head coach Mike Vrabel kept Smith as the tight ends coach for 2018. On January 21, 2019, Smith was promoted to offensive coordinator, replacing Matt LaFleur, who departed to become head coach of the Green Bay Packers two weeks prior. In his first year as offensive coordinator, Smith oversaw the highest-scoring Titans team in 16 years, with Derrick Henry, Ryan Tannehill, and Jonnu Smith having career years. Smith was praised for his play-calling in the Titans' 28–12 road victory over the top-seeded Baltimore Ravens in the AFC Divisional Round. In 2020, the Titans ranked fourth in scoring and second in total yards.
U + 2 H2SO4 → U(SO4)2 + 2 H2 2 Pu + 6 HCl → 2 PuCl3 + 3 H2 However, in these reactions the regenerating hydrogen can react with the metal, forming the corresponding hydride. Uranium reacts with acids and water much more easily than thorium. Actinide salts can also be obtained by dissolving the corresponding hydroxides in acids. Nitrates, chlorides, sulfates and perchlorates of actinides are water-soluble. When crystallizing from aqueous solutions, these salts form hydrates, such as Th(NO3)4·6H2O, Th(SO4)2·9H2O and Pu2(SO4)3·7H2O. Salts of high-valence actinides easily hydrolyze. So, colorless sulfate, chloride, perchlorate and nitrate of thorium transform into basic salts with formulas Th(OH)2SO4 and Th(OH)3NO3. The solubility and insolubility of trivalent and tetravalent actinides is like that of lanthanide salts. So phosphates, fluorides, oxalates, iodates and carbonates of actinides are weakly soluble in water; they precipitate as hydrates, such as ThF4·3H2O and Th(CrO4)2·3H2O. Actinides with oxidation state +6, except for the AnO22+-type cations, form [AnO4]2−, [An2O7]2− and other complex anions. For example, uranium, neptunium and plutonium form salts of the Na2UO4 (uranate) and (NH4)2U2O7 (diuranate) types. In comparison with lanthanides, actinides more easily form coordination compounds, and this ability increases with the actinide valence. Trivalent actinides do not form fluoride coordination compounds, whereas tetravalent thorium forms K2ThF6, KThF5, and even K5ThF9 complexes.
Sources: en.wikipedia.org
=== Potential Uses of Codon Reassignment === Artificial, synthetic, unnatural, or non-proteinogenic amino acids are used in research to help understand the construction and functionality of proteins. These artificial amino acids are also used in some medications. Researchers normally use stop codons, which do not code for an amino acid, to insert these amino acids into proteins. Since there are only three stop codons, researchers were previously limited to using only one or two artificial amino acids. There was also an option to use artificial tRNA molecules to insert artificial amino acids, but these artificial tRNA molecules are not as high quality as natural tRNA molecules, often making mistakes. The ability to reassign natural tRNA to artificial amino acids through codon reassignment unlocks many possibilities for this research. Since there are 64 possible combinations and only about 20 natural amino acids, this method would allow researchers to hypothetically insert 43 artificial amino acids into a protein, preserving one stop codon to complete the translation process properly. These advancements in genetic and protein manipulation may help scientists and doctors to deepen humanity's understanding of cellular functions and produce more effective and efficient medicines.
Shrewsbury, UK: Airlife Publishing Ltd., 1992. ISBN 1-85310-212-1. Jerram, Michael F. P-51 Mustang. Yeovil, UK: Winchmore Publishing Services Ltd., 1984, ISBN 0-85429-423-6. Johnsen, Frederick A. Bell P-39/P-63 Airacobra & Kingcobra. St. Paul, Minnesota: Voyageur Press, 1998. ISBN 1-58007-010-8. Johnsen, Frederick A. North American P-51 Mustang. North Branch, Minnesota: Specialty Press Publishers and Wholesalers, 1996. ISBN 0-933424-68-X. Kaplan, Philip. Fly Navy: Naval Aviators and Carrier Aviation: A History. New York: Michael Friedman Publishing Group Incorporated, 2001. ISBN 1-58663-189-6. Kinzey, Bert. P-51 Mustang in Detail & Scale: Part 1; Prototype through P-51C. Carrollton, Texas: Detail & Scale Inc., 1996. ISBN 1-888974-02-8. Kinzey, Bert. P-51 Mustang in Detail & Scale: Part 2; P-51D thu P-82H. Carrollton, Texas: Detail & Scale Inc., 1997. ISBN 1-888974-03-6 Knaack, Marcelle Size. Encyclopedia of U.S. Air Force Aircraft and Missile Systems: Volume 1 Post-World War II Fighters 1945–1973. Washington, D.C.: Office of Air Force History, 1978. ISBN 0-912799-59-5. Lawrence, Joseph (1945). The Observer's Book Of Airplanes. London and New York: Frederick Warne & Co. Lednicer, David A. and Ian J. Gilchrist. "A Retrospective: Computational Aerodynamic Analysis Methods Applied to the P-51 Mustang." AIAA paper 91-3288, September 1991. Lednicer, David A. "Technical Note: A CFD Evaluation of Three Prominent World War II Fighter Aircraft." Aeronautical Journal, Royal Aeronautical Society, June/July 1995. Lednicer, David A.
= 0.0546. Next, multiply this value of "K" by the time elapsed between the first and second measures of radioactivity, 19 hours: (0.0546 x 19) = 1.0368. Change the sign, to make it -1.0368, then find the "inverse Ln"; in this case 0.3546. This value is in the denominator of the decay correcting fraction, so it is the same as multiplying the numerator by its inverse (
Sources: en.wikipedia.org
Moore supports using an independent redistricting commission to draw Maryland's congressional districts, but contends that states should be able "to protect democracy and to protect their rights of their individual citizens" through redistricting until Congress acts to ban partisan gerrymandering and mid-decade redistricting. In August 2025, amid Republican efforts to redraw Texas's congressional districts to gain five congressional seats in the 2026 United States House of Representatives elections, Moore criticized the mid-decade redistricting efforts as a "partisan power grab" and said that he would "evaluate all options as states around the country make decisions regarding redistricting" with respect to Maryland. He declined to say whether he supported a bill that would automatically restart Maryland's congressional redistricting process if another state adopted a new congressional map outside of the regular decennial census period. In November 2025, Moore announced the formation of an advisory commission on redistricting in Maryland, led by U.S. senator Angela Alsobrooks and former Maryland Attorney General Brian Frosh. In January 2026, a spokesperson for Moore said that he supported the congressional redistricting plan recommended by the advisory commission, which would increase the Democratic Party's chances of winning Maryland's 1st congressional district, and called on leaders of the Maryland General Assembly to hold a vote on it.
== Operations == EFLM has an Executive Board and a range of committees for: science, education and training, quality and regulations, communication and professional representation. Each committee has working groups with a Chair and three full members, there is also a Young Scientist member and they may also have corresponding members, but only one member form each country is permitted. The Science Committee develops collaborative science in Laboratory Medicine between member organisations or individuals and guidelines to set standards of practice to assist member societies in providing quality patient care. The output of the scientific working groups is scientific papers and presentations which contribute to the science of laboratory medicine internationally; a list of publications can be found on the EFLM web-site (link below). Typically publications are peer-reviewed and published in the journal Clinical Chemistry and Laboratory Medicine. The Working Groups are overseen by the Chair of the Science Committee and their activities reviewed annually; scientific and clinically relevant output determine whether they continue. The Education and Training Committee runs educational activities particularly for trainees and those required to develop new skills as well as running scientific and clinical conferences, webinars, etc. The major Congress is Euromedlab held in conjunction with the IFCC, meetings are selected from bids by member societies at the annual General Meeting.
=== Economics === The sustained-release formulation, Contrave, is marketed by Takeda under license from the combination medication's developer, Orexigen Therapeutics. As of 2015, Orexigen received 20% of net sales from Takeda.
Sources: en.wikipedia.org
Dry powder is usually kept at about -20 degrees Celsius for long-term storage and at 2 to 8 degrees Celsius for short working periods. Containers should stay sealed and protected from light and moisture to limit degradation.
Oxidation of the methionine residue to the sulfoxide is a frequently reported change, and it usually appears as an earlier-eluting peak in reversed-phase chromatography. Backbone hydrolysis products can also accumulate in aqueous solution.
Liquid chromatography coupled with mass spectrometry is the usual approach, because the observed molecular ion can be compared with a calculated mass of about 813.9 Da. Retention time alone does not establish identity.
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。