The short version of semax fits in a sentence. The long version — which is the one that helps — is below.
This page was last updated on 2025-11-17 and is reviewed periodically as new material appears.
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.
Development of the compound took place in the Soviet Union during the 1980s, largely through peptide research groups affiliated with the Shemyakin-Ovchinnikov Institute and Moscow State University. Investigators screened fragments of adrenocorticotropic hormone for activity on the central nervous system while attempting to separate cognitive effects from hormonal ones. The shortened sequence was selected because it retained behavioral activity in animal models without stimulating corticosteroid release. Early publications described the molecule as an ACTH(4-10) analog.
Published research on this peptide originates mainly from Russian laboratories, and the wider international literature is comparatively thin. Studies have used rodent models of stroke, hypoxia, and memory tasks, with a smaller number of human trials reported. Reported outcomes include changes in attention and memory measures, along with effects on neurotrophic factor expression in some experiments. Small sample sizes, inconsistent dosing protocols, and limited independent replication are widely noted limitations, so the strength of the clinical evidence remains an open question.
Semax is a synthetic heptapeptide whose sequence is Met-Glu-His-Phe-Pro-Gly-Pro. The first four residues correspond to the ACTH(4-10) fragment, while the terminal Pro-Gly-Pro extension was added to improve metabolic stability. Its molecular formula is C37H51N9O10S and its monoisotopic mass is approximately 813.9 Da. The compound is classified as a peptide research chemical and as a registered pharmaceutical product in Russia, but it does not hold marketing approval in the European Union or the United States. Naming conventions vary across supplier catalogs.
| 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 |
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。
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。
Semax is a synthetic heptapeptide with the sequence Met-Glu-His-Phe-Pro-Gly-Pro. Its design combines the ACTH(4-7) core fragment with a C-terminal Pro-Gly-Pro extension, a modification intended to improve stability and prolong activity. The molecule is hydrophilic, carries no lipid chains or glycosylation, and has a theoretical mass just over 810 daltons in its free form. All seven residues are proteinogenic amino acids, so no non-natural building blocks appear in the backbone. A free N-terminal methionine and C-terminal proline define the unmodified parent peptide.
The compound was developed during the 1980s at the Institute of Molecular Genetics in Moscow as part of research on fragments of adrenocorticotropic hormone. Early work examined short ACTH-derived sequences that retained neurotrophic effects while lacking the endocrine activity of the full hormone. Semax entered clinical use in Russia during the 1990s, where it received registration for several neurological indications. Outside that region it remained primarily a laboratory research material rather than an approved therapeutic. English-language literature on it grew more slowly and frequently cited the original Russian studies.
Terminology around the compound varies by source. It appears in catalogues and papers as Semax, as the heptapeptide ACTH(4-7)-Pro-Gly-Pro, and under various alphanumeric laboratory codes used by individual suppliers. These names refer to the same sequence but may imply different salt forms, purity grades, or counter-ions. Peptide databases usually list the free base mass, while product descriptions sometimes report acetate or trifluoroacetate salts with a different formula weight. Because naming conventions for research peptides are not standardised across vendors, checking the declared sequence and measured mass is more reliable than relying on a trade name alone.
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。
纯度评估以反相高效液相色谱为主，通过主峰面积百分比给出粗略结果，再配合电喷雾质谱核对分子量。氨基酸分析可验证组成比例，手性色谱或毛细管电泳用于检查残基构型。常见杂质包括缺失序列的短肽、氧化产物与二聚体。由于多数市售品不附带完整检验报告，独立第三方检测常被用来核实标称值。
Hexane () or n-hexane is an organic compound, a straight-chain alkane with six carbon atoms and the molecular formula C6H14. Hexane is a colorless liquid, odorless when pure, and with a boiling point of approximately 69 °C (156 °F). It is widely used as a cheap, relatively safe, largely unreactive, and easily evaporated non-polar solvent, and modern gasoline blends contain about 3% hexane. The term hexanes refers to a mixture, composed largely (>60%) of n-hexane, with varying amounts of the isomeric compounds 2-methylpentane and 3-methylpentane, and possibly, smaller amounts of nonisomeric C5, C6, and C7 (cyclo)alkanes. These "hexanes" mixtures are cheaper than pure hexane, and are often used in large-scale operations that don't require a single isomer (e.g., as cleaning solvent or for chromatography).
Poor ventilation is one of the main causes of excessive CO2 concentrations in closed spaces, leading to poor indoor air quality. Carbon dioxide differential above outdoor concentrations at steady state conditions (when the occupancy and ventilation system operation are sufficiently long that CO2 concentration has stabilized) are sometimes used to estimate ventilation rates per person. Higher CO2 concentrations are associated with occupant health, comfort and performance degradation. ASHRAE Standard 62.1–2007 ventilation rates may result in indoor concentrations up to 2,100 ppm above ambient outdoor conditions. Thus if the outdoor concentration is 400 ppm, indoor concentrations may reach 2,500 ppm with ventilation rates that meet this industry consensus standard. Concentrations in poorly ventilated spaces can be found even higher than this (range of 3,000 or 4,000 ppm). Miners, who are particularly vulnerable to gas exposure due to insufficient ventilation, referred to mixtures of carbon dioxide and nitrogen as "blackdamp", "choke damp" or "stythe". Before more effective technologies were developed, miners would frequently monitor for dangerous levels of blackdamp and other gases in mine shafts by bringing a caged canary with them as they worked. The canary is more sensitive to asphyxiant gases than humans, and as it became unconscious would stop singing and fall off its perch.
=== Lilly's Tempo Pen === Eli Lilly's Tempo system is a diabetes management platform that includes the Tempo Pen, Tempo Smart Button, and the TempoSmart App. The Tempo Pen is a reusable insulin pen that, when paired with the Tempo Smart Button, captures and transmits insulin dose data to the TempoSmart App via Bluetooth. The TempoSmart App can integrate glucose data from compatible devices, such as the Tempo Blood Glucose Meter or Dexcom G7, allowing users to track their insulin doses, glucose levels, and other lifestyle data in one place. The app also includes features such as bolus insulin dose calculation, medication reminders, digital logbooks, trend reports, and diabetes education tools.
In fact, actin is capable of acting as a transcription initiator when it reacts with a type of nuclear myosin that interacts with RNA polymerases and other enzymes involved in the transcription process. Stereocilia dynamics. Some cells develop fine filiform outgrowths on their surface that have a mechanosensory function. For example, this type of organelle is present in the Organ of Corti, which is located in the ear. The main characteristic of these structures is that their length can be modified. The molecular architecture of the stereocilia includes a paracrystalline actin core in dynamic equilibrium with the monomers present in the adjacent cytosol. Type VI and VIIa myosins are present throughout this core, while myosin XVa is present in its extremities in quantities that are proportional to the length of the stereocilia. Intrinsic chirality. Actomyosin networks have been implicated in generating an intrinsic chirality in individual cells. Cells grown out on chiral surfaces can show a directional left/right bias that is actomyosin dependent.
Sources: en.wikipedia.org
In 1912, as part of his exploration into the composition of the streams of positively charged particles then known as canal rays, Thomson and his research assistant, F. W. Aston, channelled a stream of neon ions through a magnetic and an electric field and measured its deflection by placing a photographic plate in its path. They observed two patches of light on the photographic plate (see image on right), which suggested two different parabolas of deflection, and concluded that neon is composed of atoms of two different atomic masses (neon-20 and neon-22), that is to say of two isotopes. This was the first evidence for isotopes of a stable element; Frederick Soddy had previously proposed the existence of isotopes to explain the decay of certain radioactive elements. Thomson's separation of neon isotopes by their mass was the first example of mass spectrometry, which was subsequently improved and developed into a general method by F. W. Aston and by A. J. Dempster.
=== Archives === CBC Digital Archives – Cold War Culture: The Nuclear Fear of the 1950s and 1960s The Cold War International History Project (CWIHP) The Cold War Files CONELRAD Cold War Pop Culture Site Archived 29 July 2020 at the Wayback Machine The Persuasive Cartography, The PJ Mode Collection, Cornell University Library (Select "Communism & Cold War" value to browse maps dated 1933–1982) Preview of the War We Do Not Want published in Collier's Magazine 27 October 1951
Semen in semen cryopreservation Blood Special cells for transfusion like platelets (Thrombosomes by Cellphire) Stem cells. It is optimal in high concentration of synthetic serum, stepwise equilibration and slow cooling. Genetic Material Additionally, cryopreservation is used for gene therapy treatments e. g. for cancer patients suffering from leukemia or lymphoma. The genetic materials used for gene therapy have to be modified in vivo or ex vivo. In order to do that they need to be kept viable during transport and storage. With cryopreservation they are brought to ultra-low temperatures and thawed when needed. Umbilical cord blood in a Cord blood bank Tissue samples like tumors and histological cross sections Eggs (oocytes) in oocyte cryopreservation Embryos at cleavage stage (that are 2, 4, 8 or 16 cells) or at early blastocyst stage, in embryo cryopreservation Ovarian tissue in ovarian tissue cryopreservation Plant seeds, callus, shoots tips or dormant buds are cryopreserved for conservation purposes.
Sources: en.wikipedia.org
Particles such as whole cells or cell debris, which would clog a packed bed column, readily pass through a fluidized bed. EBA can therefore be used on crude culture broths or slurries of broken cells, thereby bypassing initial clearing steps such as centrifugation and filtration, which is mandatory when packed beds are used. In older EBA column designs, the feed flow rate is kept low enough that the solid packing remains stratified and does not fluidize completely. Hence EBA can be modelled as frontal adsorption in a packed bed, rather than as a well-mixed, continuous-flow adsorber.
=== 18 July === In Crimea, the Russian-installed governor of Sevastopol claimed that a naval drone was intercepted while attempting to attack the city. SBU naval and aerial drones also attacked a Russian coast guard base on Lake Donuzlav during a Russian naval exercise, hitting the base headquarters, ammunition depot, a power substation and technical facilities. Ukraine claimed to have shot down a Russian drone over Kyiv with no casualties recorded. The Freedom of Russia Legion claimed to have launched an attack on the Bolshoye Savino airport in Perm hosting MiG-31 fighters. A video released showed two KAMAZ trucks burning, with the group claiming to have destroyed “several units of military equipment.” Ukrainian Prime Minister Denys Shmyhal announced the extension of a system to jam Russian TV and radio broadcasts into Donetsk, Mykolaiv, Kherson, and Zaporizhzhia Oblasts.
The CDC Good laboratory practice guidelines for newborn screening recommend that "laboratory specimen retention procedures should be consistent with patient decisions." Researchers have described the NBS samples as a gold mine representing a patient population that would otherwise be impossible to get. The American Civil Liberties Union (ACLU), Council for Responsible Genetics(CRG), and the International Association of Privacy Professionals(IAPP) oppose the long term storage of identifiable NBS blood spots. In 2009, the Texas NBS program had to destroy millions of stored blood spots that had been stored for decades without consent. In Michigan, a 2022 lawsuit found that the NBS program long term storage and sales to third-parties was found to violate state statues noting how "post-testing conduct is not necessary to effectuate that interest because 'the health of the child is no longer at stake.'" In New Jersey, the Institute for Justice filed a class-action lawsuit in 2022 under the 4th amendment seeking to limit the retention period of NBS cards after they were found to be used in warrantless law enforcement investigations without consent.
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.
It is a synthetic peptide of seven amino acids. Its backbone corresponds to a fragment of adrenocorticotropic hormone extended at the carboxyl end. The material is distributed as a lyophilized solid for laboratory use.