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Last reviewed on 2026-02-10. Where a claim depends on a specific study, the study is described rather than over-claimed.
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.
Identity and purity are commonly assessed by reversed-phase high-performance liquid chromatography, with ultraviolet detection near 214 nanometers for the peptide backbone. Mass spectrometry, either electrospray or matrix-assisted laser desorption, confirms molecular mass and detects truncation or modification products. Amino acid analysis can verify composition. Because the sequence contains no strongly absorbing aromatic residue apart from phenylalanine, detection wavelengths are chosen carefully. Purity values above 95 percent are typical for research-grade material.
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.
| Property | Value | Notes |
|---|---|---|
| Chemical class | Synthetic heptapeptide | ACTH(4-7) analogue |
| Sequence | Met-Glu-His-Phe-Pro-Gly-Pro | Free N terminus, unmodified side chains |
| Molecular weight | 813.9 Da | Free base; salt forms differ |
| Appearance | White to off-white powder | Lyophilised solid |
| Solubility | Freely soluble in water | Hydrophilic; polar solvents preferred |
各国监管态度分化明显。俄罗斯按处方药管理，部分东欧国家留有使用记录；欧盟与美国未批准其作为药物上市，市面流通品通常标注为研究用化学品。身份差异意味着标示含量、纯度与无菌性缺少统一核查。体育领域还牵涉反兴奋剂名录，跨境携带则受目的地药品法规约束。
Semax 是人工设计的七肽，序列为 Met-Glu-His-Phe-Pro-Gly-Pro，骨架取自促肾上腺皮质激素片段 ACTH(4-10)。它于二十世纪八十年代在苏联的分子遗传学研究机构内合成。设计目标是保留该片段与注意力和记忆相关的活性，同时剔除促皮质激素释放等内分泌作用。此后俄罗斯将其登记为药品并进入临床使用。
当时的短肽研究普遍关注能否穿越血脑屏障、在低剂量下产生中枢效应，Semax 属于这一路线。鼻内给药是其主要使用方式，俄语文献报道的适应症涵盖缺血性卒中、短暂性脑缺血发作、认知功能减退以及视神经病变。这些研究大多发表在当地期刊上，样本规模与终点设置同西方试验惯例存在差异，国际同行对其临床证据的强度看法不一。
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.
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.
== Biological origin == Isoprenoid GDGTs originate as archaeal membrane lipids, whose fatty acids are converted to glycerol via esterification (ether lipid). They were first recognized as being associated with extremophilic archaea, but research in recent decades has discovered the compounds in a wide range of mesophilic environments as well, including soils, lake sediment, and marine deposits. Archaeal phylogenetic classes Nitrososphaerota (formerly Thaumarchaeota), Thermoproteota (formerly Crenarchaeota), "Euryarchaeota", and "Korarchaeota" produce GDGTs. Branched GDGTs are most commonly detected in peats and soils and are most associated with terrestrial settings. To date, no direct evidence for an unequivocal source organism has been reported, but the structural similarity of acidobacterial lipid to brGDGT alkyl chains strongly suggests that acidobacteriota synthesize brGDGT. The stereochemistry strongly hints at a non-archaeal origin.
Trump characterized the action as an application of the Monroe Doctrine, which he styled as the "Donroe Doctrine", and added that "American dominance in the western hemisphere will never be questioned again." Trump further stated that US oil companies would "go in, spend billions of dollars, fix the badly broken infrastructure, the oil infrastructure, and start making money for the country", and that the US was prepared to launch a second, much larger attack. He also expressed openness to a US occupation of Venezuela, stating it would not cost the US anything because it would be reimbursed through revenue from Venezuela's oil reserves. On 7 January, Trump stated that US efforts to revitalize Venezuela could take "much longer" than a year, adding that the Venezuelan authorities were doing "everything that we feel is necessary". Regarding the reward the US government offered for information leading to Maduro's capture, Rubio added that nobody will be receiving it. Rubio said "I guess we save $50 million" to which Trump replied "Don't let anybody claim it. Nobody deserves it but us." On 4 January 2026, Marco Rubio retracted Trump's comments of the day before, saying the US would not govern Venezuela, but would continue to enforce the existing oil quarantine in order to pressure Venezuela for policy changes. Rubio also affirmed that the US did not officially recognize Rodríguez's presidency, despite Trump's avowal that he would work with Rodríguez.
==== McLean v. Arkansas ==== In 1981, Kenyon was recruited to be an expert witness for the creationist side in the McLean v. Arkansas case that tested the constitutionality of Arkansas' Equal Time Legislation that mandated equal time for "creation science" and "evolution science". Kenyon flew to Arkansas to be deposed and testify during the trial. However, apparently under the influence of creationist attorney Wendell Bird (who was displeased with the defense of the creationist position by the Arkansas attorney general Steve Clark), Kenyon left town just before he was to testify:
== Cosmetics == Thickening agents used in cosmetics or personal hygiene products include viscous liquids such as polyethylene glycol, synthetic polymers such as carbomer (a trade name for polyacrylic acid) and vegetable gums. Some thickening agents may also function as stabilizers when they are used to maintain the stability of an emulsion. Some emollients, such as petroleum jelly and various waxes may also function as thickening agents in an emulsion.
Sources: en.wikipedia.org
Ertapenem, sold under the brand name Invanz, is a carbapenem antibiotic medication used for the treatment of infections of the abdomen, the lungs, the upper part of the female reproductive system, and the diabetic foot. The most common side effects include diarrhoea, nausea, headache, and problems around the area where the medicine is infused. It can significantly reduce the concentrations of valproic acid, an anti-seizure medication, in the blood to the point where it loses its effectiveness. Ertapenem was approved for medical use in the United States in November 2001, and in the European Union in April 2002. It is marketed by Merck.
== In biochemistry == Many biologically active molecules are chiral, including the naturally occurring amino acids (the building blocks of proteins) and sugars. The origin of this homochirality in biology is the subject of much debate. Most scientists believe that Earth life's "choice" of chirality was purely random, and that if carbon-based life forms exist elsewhere in the universe, their chemistry could theoretically have opposite chirality. However, there is some suggestion that early amino acids could have formed in comet dust. In this case, circularly polarised radiation (which makes up 17% of stellar radiation) could have caused the selective destruction of one chirality of amino acids, leading to a selection bias which ultimately resulted in all life on Earth being homochiral. Enzymes, which are chiral, often distinguish between the two enantiomers of a chiral substrate. One could imagine an enzyme as having a glove-like cavity that binds a substrate. If this glove is right-handed, then one enantiomer will fit inside and be bound, whereas the other enantiomer will have a poor fit and is unlikely to bind. L-forms of amino acids tend to be tasteless, whereas D-forms tend to taste sweet. Spearmint leaves contain the L-enantiomer of the chemical carvone or R-(−)-carvone and caraway seeds contain the D-enantiomer or S-(+)-carvone. The two smell different to most people because our olfactory receptors are chiral.
Throughout late November and early December, the Cubans focused on fighting the FNLA in the north, and stopping an abortive incursion by Zaire on behalf of that movement. Thereafter, they refocused on putting an end to the SADF advances in the south. The South African and Cuban forces engaged in a series of bloody, but inconclusive skirmishes and battles throughout late December. However, by this point word of the SADF's involvement had been leaked to the international press, and photographs of SADF armour behind UNITA lines were appearing in several European newspapers. This proved to be a major political setback for the South African government, which was almost universally condemned for its interference in a black African country. Moreover, it spurred influential African states such as Nigeria and Tanzania to recognise the MPLA as the sole legitimate government of Angola, as that movement's struggle against an apparent act of South African aggression gave it legitimacy at the OAU. South Africa appealed to the United States for more direct support, but when the CIA's role in arming the FNLA also became public, the US Congress terminated and disavowed the programme. In the face of regional and international condemnation, the SADF made the decision around Christmas of 1975 to begin withdrawing from Angola. The withdrawal commenced in February 1976 and formally ended a month later. As the FNLA and UNITA lost their logistical backing from the CIA and the direct military support of the SADF, they were forced to abandon much of their territory to a renewed FAPLA offensive.
nick A break or discontinuity in the phosphate backbone of one strand of a double-stranded DNA molecule, i.e. where a phosphodiester bond is hydrolyzed but no nucleotides are removed; such a molecule is said to be nicked. A nick is a single-strand break, where despite the break the DNA molecule is not ultimately broken into multiple fragments, which contrasts with a cut, where both strands are broken. Nicks may be caused by DNA damage or by dedicated nucleases known as nicking enzymes, which nick DNA at random or specific sites. Nicks are frequently placed by the cell as markers identifying target sites for enzyme activity, including in DNA replication, transcription, and mismatch repair, and also to release torsional stress from overwound DNA molecules, making them important in manipulating DNA topology.
=== Analogues === Retigabine is a bioisostere of flupirtine in which the pyridine ring has been replaced with a phenyl ring. Azetukalner (encukalner), pynegabine, and fluoxakalner are also analogues of flupirtine and retigabine.
Sources: en.wikipedia.org
== Structure and classification == Aminopeptidases are a diverse group of enzymes that play crucial roles in various biological processes, including protein digestion, cell growth, and immune response. They are classified based on their substrate specificity (strength of binding) and catalytic mechanism (means of catalyzing their reaction) into two main categories: metalloaminopeptidases and cysteine aminopeptidases. Metalloaminopeptidases use a metal ion to perform their function, and cysteine aminopeptidases use a particular cysteine amino acid. The structure of aminopeptidases varies depending on the specific enzyme, but they generally consist of a catalytic domain where the catalysis occurs and additional domains that contribute to target recognition and regulation of their functions. For instance, Aminopeptidase N (APN), a type II metalloprotease, consists of 967 amino acids with a short N-terminal cytoplasmic domain in the cytoplasm, a single transmembrane part reaching through the cellular membrane, and a large cellular ectodomain sticking out of the cell containing the active site.
The opposite property to ionisation energy is the electron affinity, which is the energy released when adding an electron to the atom. A passing electron will be more readily attracted to an atom if it feels the pull of the nucleus more strongly, and especially if there is an available partially filled outer orbital that can accommodate it. Therefore, electron affinity tends to increase down to up and left to right. The exception is the last column, the noble gases, which have a full shell and have no room for another electron. This gives the halogens in the next-to-last column the highest electron affinities. Some atoms, like the noble gases, have no electron affinity: they cannot form stable gas-phase anions. (They can form metastable resonances if the incoming electron arrives with enough kinetic energy, but these inevitably and rapidly autodetach: for example, the lifetime of the most long-lived He− level is about 359 microseconds.) The noble gases, having high ionisation energies and no electron affinity, have little inclination towards gaining or losing electrons and are generally unreactive. Some exceptions to the trends occur: oxygen and fluorine have lower electron affinities than their heavier homologues sulfur and chlorine, because they are small atoms and hence the newly added electron would experience significant repulsion from the already present ones. For the nonmetallic elements, electron affinity likewise somewhat correlates with reactivity, but not perfectly since other factors are involved.
==== Activity therapies ==== Activity therapies also called recreation therapy and occupational therapy, promote healing through active engagement. An example of occupational therapy would be promoting an activity that improves daily life, such as self-care or improving hobbies. Each of these therapies have proven to improve mental health and have resulted in healthier, happier individuals. In recent years, for example, coloring has been recognized as an activity that has been proven to significantly lower the levels of depressive symptoms and anxiety in many studies.
Vitarine Pharmaceuticals of New York, which sought approval of a generic version of the drug Dyazide, a medication for high blood pressure, submitted Dyazide, rather than its generic version, for the FDA tests. In April 1989, the FDA investigated 11 manufacturers for irregularities; and later brought that number up to 13. Dozens of drugs were eventually suspended or recalled by manufacturers. In the early 1990s, the U.S. Securities and Exchange Commission filed securities fraud charges against the Bolar Pharmaceutical Company, a major generic manufacturer based in Long Island, New York.
=== Production === Polystyrene foams are produced using blowing agents that form bubbles and expand the foam. In expanded polystyrene, these are usually hydrocarbons such as pentane, which may pose a flammability hazard in manufacturing or storage of newly manufactured material, but have relatively mild environmental impact. Extruded polystyrene is usually made with hydrofluorocarbons (HFC-134a), which have global warming potentials of approximately 1000–1300 times that of carbon dioxide. In Europe, where HFC-134a was banned since beginning 2022, XPS is produced using carbon dioxide as blowing agent, achieving an ODP (Ozone depletion potential) of 0 and a GWP (Global warming potential) below 5. Packaging, particularly expanded polystyrene, is a contributor of microplastics from both land and maritime activities.
Sources: en.wikipedia.org
It is a synthetic seven-amino-acid peptide built from the ACTH(4-7) sequence plus a Pro-Gly-Pro tail. It belongs to the family of short ACTH fragments studied for nervous-system effects. Its backbone contains only standard amino acids.
It contains the 4-7 fragment of adrenocorticotropic hormone extended at the C terminus. That truncation removes the region associated with steroidogenic activity. The design intent was to keep neurotrophic properties while avoiding full hormonal effects.
No natural source of the intact heptapeptide is known. It is produced by solid-phase peptide synthesis. Some related ACTH fragments arise as hormone processing products, but the Pro-Gly-Pro extension is a designed addition rather than a natural sequence.
Solid peptide is best kept frozen at about minus 20 degrees Celsius in a sealed container with desiccant. It should be allowed to reach room temperature before opening to prevent condensation. Repeated warming and cooling of the same vial is discouraged.