mass spectrometry comes up often in conversation and rarely with the context attached. Here we lay out the basics in order, then work through the practical considerations.
Updated 2025-12-15. Numbers and descriptions here follow the published literature rather than marketing material.
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.
Identity and purity are established with standard peptide methods. Reversed-phase HPLC with ultraviolet detection near 214 nm resolves the parent peak from deletion and truncation byproducts, and reports typically quote a main-peak percentage. Mass spectrometry by electrospray or MALDI-TOF confirms the expected molecular mass, while amino acid analysis or peptide mapping can verify composition when the sequence itself is in question. A certificate of analysis that pairs a chromatogram with a mass spectrum is more informative than a purity figure alone. Counter-ion content and residual solvents are separate specifications and are frequently omitted.
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.
Pharmacological accounts link semax to melanocortin signalling and to modulation of neurotrophic factor expression, particularly brain-derived neurotrophic factor and nerve growth factor. Much of this evidence comes from rodent studies using intranasal delivery, a route chosen because it allows peptides to reach the central nervous system with limited systemic exposure. Whether the same mechanisms operate in humans at comparable magnitude remains an open question. The precise receptor or receptors responsible for the reported behavioural and neuroprotective effects have not been conclusively identified.
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.
| Property | Value | Notes |
|---|---|---|
| Solid storage temperature | -20 °C or below | Desiccated and protected from light |
| Solution storage temperature | -80 °C as single-use aliquots | Avoid repeated freeze-thaw cycles |
| Purity assessment method | RP-HPLC, around 214 nm | Reported as main-peak area percent |
| Identity confirmation method | ESI-MS or MALDI-TOF | Measured mass compared with calculated mass |
| Common synonyms | ACTH(4-10) analog; Met-Glu-His-Phe-Pro-Gly-Pro | Also written as Semaxum in some sources |
Published studies examine a fairly narrow set of endpoints. Rodent experiments commonly measure maze learning, infarct volume after induced ischemia, and tissue levels of neurotrophic factors. Clinical reports from Russian centres describe attention, memory and recovery scores in patients after stroke or transient ischemic attack. Most of those human studies are small and few have been repeated by independent groups. Outcome measures differ between studies, which limits direct comparison.
Circulation time for the peptide is short because peptidases cleave it readily. The Pro-Gly-Pro tail is thought to slow breakdown compared with the bare ACTH fragment, but the gain appears modest. Absorption after intranasal dosing is limited, and only a fraction of a dose is expected to reach the central nervous system. Laboratory concentrations therefore sit well above levels achieved systemically, a gap that complicates translation from bench findings to clinical claims.
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。
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。
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ATP synthase, also called complex V, is the final enzyme in the oxidative phosphorylation pathway. This enzyme is found in all forms of life and functions in the same way in both prokaryotes and eukaryotes. The enzyme uses the energy stored in a proton gradient across a membrane to drive the synthesis of ATP from ADP and phosphate (Pi). Estimates of the number of protons required to synthesize one ATP have ranged from three to four, with some suggesting cells can vary this ratio, to suit different conditions.
The news website Tortoise Media reports that the Conservatives have received a further £5m in donations from Frank Hester that are yet to be declared. 16 March Vaughan Gething is elected to lead Welsh Labour, and will become First Minister of Wales. He will be Wales's first black leader, and the first black person to lead a country in Europe. Sainsbury's apologises to its online customers after a technical error meant that orders could not be fulfilled. 18 March – At Manchester Crown Court, Jacob Graham is sentenced to 13 years in prison together with a further five year extended period on licence for creating a "freedom encyclopaedia" containing details on how to build weapons for the purposes of terrorism. 19 March At Southend Crown Court, 39-year-old Nicholas Hawkes, the first person in England and Wales to be convicted of cyberflashing, is sentenced to 66 weeks in prison. This new offence follows passage of the Online Safety Act, which came into effect on 31 January. HMRC announces that its self-assessment helpline will be closed for six months of the year, with the line scheduled to close from 8 April to 30 September. Customers seeking help during that period will be forced to use an online chatbot. The British Board of Film Classification updates its guidelines, meaning films containing scenes of sex or nudity are more likely to receive a 15 rather than a 12A rating going forward. 20 March Inflation falls from 4% to 3.4%, its lowest rate since September 2021.
Sources: en.wikipedia.org
During 1942, the brigade focused on the "Rail War", conducting extensive sabotage operations on the Vitebsk-Nevel and Polotsk-Nevel railway lines. They also routed German garrisons at the Bychikha and Yezerishche stations and in various villages in the Gorodok District. In early 1943, German Command launched a series of anti-partisan sweeps. Following a Period of intense combat near the villages of Tsari and Budnista, the brigade, which had numbered 597 partisans, was forced to retreat across the frontlines into Soviet-held territory on March 4th, 1943, leading to the brigade's temporary dissolution.
=== China (mainland) === The National Administration of Traditional Chinese Medicine was created in 1949, which then absorbed existing TCM management in 1986 with major changes in 1998. China's National People's Congress Standing Committee passed the country's first law on TCM in 2016, which came into effect on 1 July 2017. The new law standardized TCM certifications by requiring TCM practitioners to (i) pass exams administered by provincial-level TCM authorities, and (ii) obtain recommendations from two certified practitioners. TCM products and services can be advertised only with approval from the local TCM authority. Ready-to-use TCM preparations, also known as Chinese patent medicines, are regulated by the National Medical Products Administration (and its predecessor CFDA) similar to preparations used in modern medicine since 1984. The barrier for entry, however, is much lower than medications based on modern/non-TCM principles; the rules allow for omitting clinical testing in a variety of circumstances. As of 2025, the latest (2020) rules allow a simplified procedure for preparations derived from an approved list of "classic prescriptions". The government-run healthcare system covers a number of TCM procedures and preparations. In 2021, a total of 7114.5 billion yuan went into healthcare, amounting for 6.59% of the year's national GDP. Of these, 1111.5 billion yuan went into covering costs associated with TCM preparations (0.97% of national GDP), with 592.4 billion yuan covering the actual medications.
After Constantinople fell, the Ottomans quickly absorbed the remaining independent territories, including Acciaiuoli Athens in 1458, Morea in 1460, Trebizond in 1461, and Gattilusi Lesbos in 1462. They dismantled the Empire's political and secular institutions, leaving the impoverished Church to manage what would be later called the Rum Millet, primarily as a tool for taxing its followers. As the sole sovereign Orthodox state, Russia developed the Third Rome doctrine, emphasising its cultural heritage as distinct from Western Europe, because the latter had inherited much of the empire's secular learning. The Danubian Principalities became a haven for Orthodox Christians and Phanariot Greeks who sought to recreate a Byzantine Greek Empire. In modern Greece, members of the Rum Millet increasingly identified as Greeks, eventually leading to a successful war of independence in the 19th century. The modern Greek state nearly doubled its territory through the pursuit of the Megali Idea—a vision of reclaiming the former lands of the eastern empire—achieving limited success during the Crimean War but making significant gains during the Balkan Wars. Since the 15th century, Byzantine history has been deeply politicised, woven into nationalist, colonialist, and imperialist narratives. This politicisation appears not only in Greece but also in Bulgarian, Romanian, Serbian, Hungarian, and Turkish nationalism, as well as in former French and Russian imperialist agendas.
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Sources: en.wikipedia.org
=== Sports and entertainment === Jack Kramer, 1939: tennis player in International Tennis Hall of Fame Tom Tellez, 1951: former track coach at the University of Houston Darlene Hard, 1954: tennis player in International Tennis Hall of Fame Ivan Guevara, 1955: former college basketball coach at Whittier College and San Jose State University Barney Rosenzweig, 1955: television producer Jerry Pimm, 1956: former basketball coach at University of Utah Bobby Knoop, 1956: retired MLB second baseman for California Angels, Chicago White Sox, and Kansas City Royals Edward James Olmos, 1964: actor and director John Madrid, 1966: jazz and pop music trumpeter
Matrix metalloproteinases (MMPs), also known as matrix metallopeptidases or matrixins, are metalloproteinases that are calcium-dependent zinc-containing endopeptidases; other family members are adamalysins, serralysins, and astacins. The MMPs belong to a larger family of proteases known as the metzincin superfamily. Collectively, these enzymes are capable of degrading all kinds of extracellular matrix proteins, but also can process a number of bioactive molecules. They are known to be involved in the cleavage of cell surface receptors, the release of apoptotic ligands (such as the FAS ligand), and chemokine/cytokine inactivation. MMPs are also thought to play a major role in cell behaviors such as cell proliferation, migration (adhesion/dispersion), differentiation, angiogenesis, apoptosis, and host defense. They were first described in vertebrates in 1962, including humans, but have since been found in invertebrates and plants. They are distinguished from other endopeptidases by their dependence on metal ions as cofactors, their ability to degrade extracellular matrix, and their specific evolutionary DNA sequence.
=== Leiomyomatosis === Diffuse leiomyomatosis of the oesophagus and tracheobronchial tree has been reported in some families with Alport syndrome. Symptoms usually appear in late childhood and include dysphagia, postprandial vomiting, substernal or epigastric pain, recurrent bronchitis, dyspnea, cough, and stridor. Leiomyomatosis is confirmed by computed tomography (CT) scanning or magnetic resonance imaging (MRI).
Twenty isotopes and six nuclear isomers (excited states of an isotope) of berkelium have been characterized, with mass numbers ranging from 233 to 253 (except 237). All of them are radioactive. The longest half-lives are observed for 247Bk (1,380 years), 248Bk (unknown, almost surely over 300 years), and 249Bk (327.2 days); other isotopes are less than a week. The isotope which is the easiest to synthesize (reactor neutron capture) is berkelium-249. This emits mostly soft β-particles which are inconvenient for detection. Its alpha radiation is rather weak (1.45×10−3%) with respect to the β-radiation, but is sometimes used to detect this isotope. The second important berkelium isotope, berkelium-247, is beta-stable and an alpha emitter, as are most long-lived actinide isotopes.
The Kingdom of Naples passed to Charles' eight-year-old son, Ferdinand IV of the Two Sicilies, under the tutelage of a regency council dominated by Tanucci. This allowed the continuation of the minister's reform policies, particularly in the ecclesiastical field. This culminated in the expulsion of the Jesuits from the Kingdom in 1769 and the forfeiture of their property. Even after Ferdinand came of age, Tanucci remained in office, but in 1774 he was exonerated at the instigation of Queen Maria Carolina of Austria, who wanted to bring Naples into the Austrian sphere of influence. However, the king continued season, pandering to the Neapolitan Enlightenment (Ferdinando Galiani, Antonio Genovesi and Gaetano Filangeri). During this period Calabria experienced major natural disasters, accompanied by social and economic changes: the plague arrived in 1743, striking Reggio Calabria and its surroundings from Messina, delaying the compilation of the cadastre onciario by local universities. The earthquake of 1783 struck southern Calabria killing some 50,000 and destroying Reggio, which was rebuilt according to more rational and linear architectural criteria. TKing Ferdinand IV sent the prince of Strongoli, Francesco Pignatelli, to cope with emergencies in the earthquake-affected areas. To finance the immense reconstruction expenses, he established the Cassa Sacra, to manage funds derived from the expropriation of abolished ecclesiastical property and monasteries.
Sources: en.wikipedia.org
Each freeze-thaw cycle can degrade a fraction of the peptide and promote aggregation. Dividing a stock solution into single-use volumes removes repeated cycling as a variable. It also limits the time a thawed solution spends at room temperature.
A high main-peak percentage says little about identity, counter-ion content, or residual solvents. It also does not distinguish an isomer or a closely eluting analog. Mass confirmation and the accompanying documentation cover those gaps.
Salt form changes mass, solubility, and hygroscopicity, and acetate and trifluoroacetate salts behave differently in solution. Storage guidance still centers on -20 °C for powder and lower temperatures for solutions. The certificate should state which salt is present.
It is described as a synthetic analogue of the ACTH(4–10) fragment, a short segment of adrenocorticotropic hormone. Its sequence differs from that fragment and includes two proline residues, which influence stability and behaviour in solution.