Everything below concerns heptapeptide. We keep the language plain, cite what the science says, and separate well-supported claims from open questions.
Updated 2026-07-12. Numbers and descriptions here follow the published literature rather than marketing material.
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.
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 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. It corresponds to the ACTH(4-7) fragment extended at the C-terminus by a Pro-Gly-Pro tripeptide, an addition intended to slow enzymatic breakdown. The molecular formula is C37H51N9O10S and the molecular mass is approximately 814 daltons. In the literature it is often described as an ACTH(4-10) analog, although that label reflects a naming convention as much as a precise structural relationship. The compound was developed in Russia and remains most closely associated with that research tradition.
Laboratory descriptions of the material are consistent across suppliers. It appears as a white to off-white lyophilized powder that dissolves readily in water and in polar organic solvents such as dimethyl sulfoxide. Aqueous solutions are clear and colorless at low concentrations. Because the peptide contains methionine, oxidation at the sulfur atom is a recognized degradation pathway, and handling notes usually call for protected, desiccated storage. Reported purity for research-grade lots is generally above 95 percent as measured by reversed-phase high-performance liquid chromatography.
The compound is registered in Russia as a pharmaceutical product, most commonly formulated as a nasal solution, and has been used in that setting since the 1990s. Outside that jurisdiction it is generally handled as a research chemical rather than an approved medicine. Regulatory status therefore differs sharply between countries, and material sold internationally may not correspond to the Russian pharmaceutical formulation. Documentation with commercial samples is typically limited to a certificate of analysis covering purity and identity, not clinical status or local legal classification.
=== Evolutionary variation of homologous RNA sequences reveals folding patterns === Additional tRNA molecules were purified and sequenced. The first comparative sequence analysis was done and revealed that the sequences varied through evolution in such a way that all of the tRNAs could fold into very similar secondary structures (two-dimensional structures) and had identical sequences at numerous positions (e.g. CCA at the 3′ end). The radial four-arm structure of tRNA molecules is termed the "cloverleaf structure", and results from the evolution of sequences with common ancestry and common biological function. Since the discovery of the tRNA cloverleaf, comparative analysis of numerous other homologous RNA molecules has led to the identification of common sequences and folding patterns.
== See also == Anti-materiel rifle Inventory Matériel (French Army) Military acquisition Military logistics Military supply chain management Supply chain United States Army Materiel Command Air Force Materiel Command United States Army Medical Research and Materiel Command
== Expat destinations == Top Expat Destinations 2019: In a 64 nation survey, Thailand was ranked as the 25th best destination for expats (1=best; 64=worst). Six ASEAN nations were ranked. They were ranked: Vietnam, 2; Singapore, 6; Malaysia, 9; Philippines, 27; and Indonesia, 29. Thailand, in a 2017 survey, ranked 18 of 55 nations (1=most desirable; 55=least desirable) in a ranking by expats of their favoured destinations. Other ASEAN nations ranked were Singapore, 9; Vietnam, 12; Malaysia, 15; Cambodia, 24; Philippines, 29; and Myanmar, 48.
Enzyme replacement therapy Certain lysosomal storage diseases are treated with infusions of a recombinant enzyme (produced in a laboratory), which can reduce the accumulation of the compounds in various tissues. Examples include Gaucher disease, Fabry disease, Mucopolysaccharidoses and Glycogen storage disease type II. Such treatments are limited by the ability of the enzyme to reach the affected areas (the blood brain barrier prevents enzyme from reaching the brain, for example), and can sometimes be associated with allergic reactions. The long-term clinical effectiveness of enzyme replacement therapies vary widely among different disorders.
Sources: en.wikipedia.org
=== Medical imaging === A physician may diagnose an inguinal hernia, as well as the type, from medical history and physical examination. For confirmation or in uncertain cases, medical ultrasonography is the first choice of imaging, because it can both detect the hernia and evaluate its changes with for example pressure, standing and Valsalva maneuver. When assessed by ultrasound or cross sectional imaging with CT or MRI, the major differential in diagnosing indirect inguinal hernias is differentiation from spermatic cord lipomas, as both can contain only fat and extend along the inguinal canal into the scrotum. On axial CT, lipomas originate inferior or lateral to the cord, and are located inside the cremaster muscle, while inguinal hernias lie anteromedial to the cord and are not intramuscular. Large lipomas may appear nearly indistinguishable as the fat engulfs anatomic boundaries, but they do not change position with coughing or straining.
The vaginal plate is the precursor to the vagina. During development, the vaginal plate begins to grow where the fused ends of the paramesonephric ducts (Müllerian ducts) enter the back wall of the urogenital sinus as the sinus tubercle. As the plate grows, it significantly separates the cervix and the urogenital sinus; eventually, the central cells of the plate break down to form the vaginal lumen. This usually occurs by the twenty to twenty-fourth week of development. If the lumen does not form, or is incomplete, membranes known as vaginal septa can form across or around the tract, causing obstruction of the outflow tract later in life. There are conflicting views on the embryologic origin of the vagina. The majority view is Koff's 1933 description, which posits that the upper two-thirds of the vagina originate from the caudal part of the Müllerian duct, while the lower part of the vagina develops from the urogenital sinus. Other views are Bulmer's 1957 description that the vaginal epithelium derives solely from the urogenital sinus epithelium, and Witschi's 1970 research, which reexamined Koff's description and concluded that the sinovaginal bulbs are the same as the lower portions of the Wolffian ducts. Witschi's view is supported by research by Acién et al., Bok and Drews. Robboy et al. reviewed Koff and Bulmer's theories, and support Bulmer's description in light of their own research. The debates stem from the complexity of the interrelated tissues and the absence of an animal model that matches human vaginal development.
Isotope masses from: M. Wang; G. Audi; A. H. Wapstra; F. G. Kondev; M. MacCormick; X. Xu; et al. (2012). "The AME2012 atomic mass evaluation (II). Tables, graphs and references" (PDF). Chinese Physics C. 36 (12): 1603–2014. Bibcode:2012ChPhC..36....3M. doi:10.1088/1674-1137/36/12/003. hdl:11858/00-001M-0000-0010-23E8-5. S2CID 250839471. Archived from the original (PDF) on 2013-09-28. Retrieved 2013-07-03. Audi, Georges; Bersillon, Olivier; Blachot, Jean; Wapstra, Aaldert Hendrik (2003), "The NUBASE evaluation of nuclear and decay properties", Nuclear Physics A, 729: 3–128, Bibcode:2003NuPhA.729....3A, doi:10.1016/j.nuclphysa.2003.11.001 Half-life, spin, and isomer data selected from the following sources. Audi, Georges; Bersillon, Olivier; Blachot, Jean; Wapstra, Aaldert Hendrik (2003), "The NUBASE evaluation of nuclear and decay properties", Nuclear Physics A, 729: 3–128, Bibcode:2003NuPhA.729....3A, doi:10.1016/j.nuclphysa.2003.11.001 National Nuclear Data Center. "NuDat 3.0 database". Brookhaven National Laboratory. Holden, Norman E. (2004). "11. Table of the Isotopes". In Lide, David R. (ed.). CRC Handbook of Chemistry and Physics (85th ed.). Boca Raton, Florida: CRC Press. ISBN 978-0-8493-0485-9.
Sources: en.wikipedia.org
==== Nucleic acid-based molecules ==== Nanogels are advantageous carriers of small, nucleic-acid based molecules that can be employed to treat a variety of diseases. Examples of three different types of molecules that fall into this category, oligonucleotides, miRNA, and nucleoside analogs, are discussed here. In one study, cationic synthetic nanogels modified with insulin and transferrin were synthesized to transport oligonucleotides, a possible therapeutic and diagnostic tool for neurodegenerative disorders, to the brain. These nanogels successfully localized through an in vitro model of the blood-brain barrier and accumulated in the brain in a mouse model. With the treatment of cardiovascular diseases in mind, polysaccharide-based nanogels have been functionalized with fucoidan to target overexpressed P-selectin receptors on platelets and endothelial cells. After loading with miRNA, these nanogels bound to platelets and became internalized by an endothelial cell line. Nanogels have also been used to encapsulate phosphorylated nucleoside analogs, or active forms of anticancer therapeutics. In one study, nanogels loaded with nucleoside 5'-triphosphates underwent surface modifications and successfully bound to overexpressed folate receptors on breast cancer cells. These nanogels were then internalized by the cells and produced a significant increase in cytotoxicity compared to control groups.
The Government of India has designated official national symbols that represent the Republic of India. These symbols serve as the representation of the country's identity. When India obtained independence from the British Raj on 15 August 1947, the Tricolour flag officially became the first national symbol of the Dominion of India. The Indian rupee, which was in circulation earlier, was adopted as the official legal tender after independence. The State Emblem with the motto Satyameva Jayate was adopted later on 30 December 1947. The National Anthem and Song were adopted two days before the Constitution of India was adopted on 26 January 1950. After India became a republic following the enactment of the Constitution, the national symbols officially came to represent the Republic of India. The last to be adopted as a national symbol was the national microbe, Lactobacillus delbrueckii, in October 2012.
This is based on the absence of Neanderthal mtDNA, as well as the relatively low level of Neanderthal admixture in the modern human X chromosome. According to Svante Pääbo, it is not clear that modern humans were socially dominant over Neanderthals, which may explain why the interbreeding occurred primarily between Neanderthal males and modern human females. A 2026 study confirmed the evidence of sex bias, reporting that sexual selection (i.e., a preference for male Neanderthals and modern human females) was the primary driver of the asymmetric mating patterns, rather than sex biases in demography or migration. Neanderthals in the Siberian Altai Mountains interbred with the local Denisovan population, and it may have been a common occurrence here. About 17% of the genome of one Altai Denisovan specimen derived from Neanderthals. Even before genetic evidence had confirmed this admixture, hybridisation between Neanderthals and early modern humans had been proposed early on, such as by English anthropologist Thomas Huxley in 1890, Danish ethnographer Hans Peder Steensby in 1907, and Coon in 1962. In the early 2000s, supposed hybrid specimens were discovered: Lagar Velho 1 and Muierii 1. These proposals were based on shared anatomy, but modern geneticists have cautioned that some shared anatomy might have been acquired by adaptation to a similar environment, rather than admixture alone.
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.
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.