neurotrophic factor raises a handful of sensible questions. This page answers them in order, starting with the fundamentals and moving to applications.
Reviewed 2026-01-17. Anything still debated is marked as such rather than presented as settled.
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。
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 |
|---|---|---|
| 分子式 | C37H51N9O10S | 游离碱形式 |
| 等电点 | 约 6.5 | 估算值，随缓冲体系变化 |
| 主要降解途径 | 水解与氧化 | 侧链氧化最为常见 |
| 溶液储存 | 2 至 8 摄氏度避光 | 避免反复冻融 |
| 常规分析手段 | 反相色谱与质谱联用 | 氨基酸分析辅助核对 |
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.
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.
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.
== Isolation == Veratridine has been isolated from the seeds of Schoenocaulon officinale and from the rhizomes of Veratrum album. Like the other steroidal alkaloids found in these plants and similar ones in the Melanthiaceae family, it is present as part of a glycosidal combination, bonded to carbohydrate moieties. Early isolation methods relied on formation of the nitrate salt and then precipitation of the insoluble sulfate form. Accounts of these efforts date back to 1878, but the first true purification of veratridine is the one carried out in 1953 by Kupchan et al. This, and later purification procedures, begin with veratrine, a mixture of the alkaloids present in the Veratrum plants, primarily containing cevadine and veratridine. The nitrate salt is formed by dissolving the veratrine in 1% sulfuric acid over ice and precipitating with sodium nitrate. After resuspending in water over ice, the solution is brought to pH 8.5 with aqueous NaOH and then pH 10 with aqueous ammonia, forming another precipitate which is extracted with ether and then with chloroform. The ether and chloroform fractions are combined and dried. The dried residue is dissolved in sulfuric acid and the sulfate salt of veratridine is precipitated by dropwise addition of a solution of ammonium sulfate. Finally, the free base form is generated with ammonium hydroxide.
==== Methodological issues in studies ==== Knowledge about the pharmacokinetics of oral progesterone has been complicated by the use of flawed analytical techniques. When progesterone is taken orally, due to first-pass metabolism, very high levels of its metabolites occur. Most previous studies have used a method known as immunoassay (IA) to measure progesterone levels. However, IA without chromatographic separation (CS) has high cross-reactivity and is unable to differentiate between progesterone and metabolites such as allopregnanolone and pregnanolone. As a result, studies that have assessed the pharmacokinetics of oral progesterone using IA have reported falsely high progesterone levels and inaccurate dependent pharmacokinetic parameters. Comparative studies using reliable and exact methods such as liquid chromatography–mass spectrometry (LC–MS) and IA in conjunction with adequate CS have found that IA without CS overestimates levels of progesterone by 5- to 8-fold. For this reason, the use of reliable assays is mandatory when studying the pharmacokinetics of oral progesterone, and an awareness of these methodological issues is likewise essential for an accurate understanding of the pharmacokinetics of oral progesterone. Conversely, the same issues are not applicable to parenteral routes of progesterone such as vaginal administration and intramuscular injection, because these routes are not subject to a first pass and relatively low levels of progesterone metabolites are formed.
=== 24 February === The SAF claimed to have taken the eastern part of the Soba Bridge. The SAF said that it had partially broken the siege of Dalang and captured the Al-Karkal, Koli, and Kiqa regions north of Kadugli and Hajar Al-Jawad and Karkariya to the south. The RSF claimed to have shot down an Ilyushin fighter jet over Nyala, killing its crew. The pilot was later identified as Major General Abulgasem Ali. The National Umma Party removed Fadlallah Burma Nasir as its acting leader following his cosigning of the Government of Peace and Unity agreement with the RSF. In response, Nasir ordered the dissolution of the party's Presidential Institution.
== External links == Official website Centers for Medicare and Medicaid Services in the Federal Register Centers for Medicare & Medicaid Services in the Code of Federal Regulations Centers for Medicare & Medicaid Services reports and recommendations from the Government Accountability Office Grants to States for Medicaid account on USAspending.gov Centers for Medicare and Medicaid Innovation account on USAspending.gov State Grants and Demonstration account on USAspending.gov Centers for Medicare and Medicaid Services apportionments on OpenOMB GitHub Repositories GitHub Repositories for Digital Service at CMS
Sources: en.wikipedia.org
==== United States ==== DOBU is not an explicitly controlled substance in the United States. However, it could be considered a controlled substance under the Federal Analogue Act if intended for human consumption.
Dominion Voting Systems announces that they have sued Fox Corporation and Fox Broadcasting Company, the parent company of Fox News, for defamation and for failing to preserve documents relating to the role Rupert Murdoch played in spreading false claims about Dominion. November 9 – The South Dakota Legislature votes to consider the impeachment of Attorney General Jason Ravnsborg. November 11 – Vice President Harris travels to Paris to deliver a speech at the Paris Peace Forum. November 12 – United States Attorney General Merrick Garland announces that former White House Chief Strategist Steve Bannon has been charged by the Department of Justice for refusing to testify to the January 6 select committee investigating the Capitol riot and refusing to provide documents requested by the committee. Bannon turned himself in to the FBI three days later. November 13 – While speaking before a "ReAwaken America" audience in November 2021, Former Trump National Security Advisor Michael Flynn said, "If we are going to have one nation under God, which we must, we have to have one religion. One nation under God, and one religion under God." causing some outrage. November 15 Radio host and conspiracy theorist Alex Jones is found liable for damages in lawsuits brought by parents of children killed in the Sandy Hook elementary school shooting, over Jones's false claim the massacre was a hoax. President Biden signs the Infrastructure Investment and Jobs Act into law. November 16 – Maryland reports their first case of monkeypox in a resident who traveled from Nigeria. November 17 – The U.S.
== Micro-structures == There are many applications of directed assembly in the micro-scale, from tissue engineering to polymer thin-films. In tissue engineering, directed assembly have been able to replace scaffolding approach of building tissues. This happens by controlling the position and organization of different cells, which are the "building blocks" of the tissue, into different desired micro-structures. This eliminates the error of not being able to reproduce the same tissue, which is a major issue in the scaffolding approach.
Sources: en.wikipedia.org
Bronzers are a temporary sunless tanning or bronzing option. These come in powders, sprays, mousse, gels, lotions and moisturizers. Once applied, they create a tan that can easily be removed with soap and water. Like make-up, these products tint or stain a person's skin only until they are washed off. They are often used for "one-day" only tans, or to complement a DHA-based sunless tan. Many formulations are available, and some have limited sweat or light water resistance. Walnut oil extract, jojoba extract, and caramel are ingredients frequently used in temporary bronzers. If bronzer is applied under clothing, or where fabric and skin edges meet, most will create some light but visible rub-off. Dark clothing prevents the rub-off from being noticeable. While these products are much safer than tanning beds, the color produced can sometimes look orangey and splotchy if applied incorrectly. A recent trend is that of lotions or moisturizers containing a gradual tanning agent. A slight increase in color is usually observable after the first use, but color will continue to darken the more frequently the product is used. Just as with the term "sunless tanner", the term "bronzer" is likewise not defined by law, or by regulations enforced by the FDA. What is defined and regulated is the color additive DHA, or dihydroxyacetone. (Note that the "color additive" dihydroxyacetone is itself colorless.) Many of these bronzers contain allergens such as benzyl alcohol, tocopherol (vitamin E), and fragrances.
From the perspective of commerce, the most important compounds are molybdenum disulfide (MoS2) and molybdenum trioxide (MoO3). The black disulfide is the main mineral. It is roasted in air to give the trioxide:
=== 25 November === According to U.S. and Ukrainian officials, about 1/3 of Western-supplied artillery went out of action in Ukraine due to wear-related mechanical problems. The United States European Command was said to have a repair base in Poland, but there were problems in transporting the weapons there from the front.
Sources: en.wikipedia.org
电喷雾或基质辅助激光解吸电离质谱是常用手段，测得的质子化离子质荷比可换算为分子量。结果与理论值落在合理误差内，才支持结构一致的判断。
甲硫氨酸侧链含硫醚，在氧气、光照或金属离子存在时容易被氧化。氧化产物极性略增，常在色谱图上表现为主峰之前的肩峰或前伸峰。
通常建议冷藏避光，并在较短时间内使用。不存在适用于所有配方的统一期限，具体取决于浓度、缓冲体系与容器材质。
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.