If you have been reading about Oxidation and want a single page that covers the useful parts, this is it: definitions, context, how it is studied, and the questions that come up repeatedly.
Last reviewed on 2025-11-30. Where a claim depends on a specific study, the study is described rather than over-claimed.
Semax is a synthetic heptapeptide developed in the Soviet Union during the 1980s by researchers at the Institute of Molecular Genetics in Moscow. It was designed as a truncated analog of adrenocorticotropic hormone, retaining only the fragment spanning residues four through ten. Investigators sought a peptide that would preserve the cognitive effects associated with ACTH while eliminating the hormonal stimulation of the adrenal cortex. The compound entered clinical use in Russia during the following decade.
Russian regulatory authorities approved the peptide for nasal administration, and it remains listed in the national pharmacopoeia under several trade names. Documented indications include acute ischemic stroke, transient ischemic attacks, traumatic brain injury, and certain ophthalmological and neurological conditions. Physicians also prescribe it for cognitive complaints in older patients, although the evidence base for that use is thinner. Outside Russia and a few neighboring states, the substance is not an approved medicine and is sold instead as a research chemical.
Later generations of the molecule include an N-acetylated form and an amidated form, both marketed online alongside the parent peptide. These variants differ in terminal chemistry and stability, and they are frequently discussed in the same breath even though they have not been compared in controlled trials. Supply outside formal healthcare systems comes largely from laboratories that synthesize peptides to order. Purity and identity of these materials vary widely, and no single body oversees the international trade.
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。
常规纯度与身份确认依赖反相高效液相色谱，并辅以质谱测定分子量。氨基酸组成分析可用于验证序列构成，肽图分析则能进一步定位修饰或降解产物。杂质谱通常关注缺失序列肽、截短片段和氧化产物。不同方法的检出限并不相同，因此各实验室报告的纯度数值不宜直接横向比较。
| Property | Value | Notes |
|---|---|---|
| Molecular class | Synthetic heptapeptide | Analog of an ACTH fragment |
| Amino acid length | Seven residues | Met-Glu-His-Phe-Pro-Gly-Pro |
| Origin | Moscow, 1980s | Institute of Molecular Genetics |
| Approved regions | Russia and some neighboring states | Not cleared in Western markets |
| Common trade names | Multiple national brands | Sold as a nasal formulation |
Semax is a synthetic heptapeptide whose sequence is Met-Glu-His-Phe-Pro-Gly-Pro. It was developed as a fragment analog of adrenocorticotropic hormone, modeled specifically on the ACTH(4-10) region. The first four residues reproduce that fragment, while a Pro-Gly-Pro tripeptide is appended at the C-terminus. Work on the compound originated in Russia, where it entered clinical use as an intranasal preparation. Its sequence places it among short regulatory peptides studied for effects on the central nervous system rather than on the adrenal axis.
The C-terminal Pro-Gly-Pro extension is not incidental. Proline-rich tails are known to resist several common peptidases, and the published literature attributes the longer half-life of Semax, relative to unmodified ACTH fragments, to this feature. The modification also removes the melanocyte-stimulating and corticosteroidogenic activity that characterizes longer ACTH-derived sequences. Because the molecule is small and hydrophilic, it is typically formulated as an aqueous solution for intranasal or parenteral delivery. Acetylation or amidation at the termini appears in closely related research peptides and shifts the mass by a fixed increment.
The peptide is prone to several degradation pathways. Oxidation of the methionine residue produces a sulfoxide that elutes close to the parent peak in many chromatographic systems. Hydrolysis of peptide bonds and deamidation of susceptible residues in related sequences also reduce purity over time. Lyophilised material kept dry at minus twenty degrees Celsius and shielded from light is the most stable form commonly described in laboratory practice.
Material sold for laboratory use varies widely in stated purity and documentation. A certificate of analysis should list the analytical method, the column and detector used, and the observed purity value. Independent verification by an outside laboratory is the practical way to confirm identity when documentation is absent or internally inconsistent. Regulatory status differs by country, and a product legal in one jurisdiction may be unapproved or controlled in another.
In the following years, it became the basis for the prosecutions of the opposition and the officers during the imposition of the totalitarian regime in the country. Between 23 and 31 January, Kimon Georgiev visited Moscow, where he met Joseph Stalin and Georgi Dimitrov for the first time. The main purpose of the visit was the conclusion, with Soviet mediation, of an alliance treaty between Bulgaria and Yugoslavia. Secret letters to the treaty envisaged the future creation of a federation, without specifying whether on an equal basis between the two countries, which Bulgaria insisted on, or by incorporating Bulgaria into Yugoslavia as a sixth republic, which was the Yugoslav position. The treaty was never concluded because of the opposition of the United Kingdom and the United States, who believed that Bulgaria could not act independently until a peace treaty was concluded. On 9 February 1945, Kimon Georgiev gave a report on the government's work to the First Congress of the Fatherland Front. Days after the first executions under the decision of the so-called People's Court, he deplored the "cases of self-destruction, arbitrariness and violence" that had been allowed to take place, claimed that they had been curbed quickly, and expressed satisfaction at their being channeled through the People's Court. He states that the constitution and "the rights and liberties of the Bulgarian people" have been restored, although the Council of Ministers rules by ordinance-laws and political organizations outside the Fatherland Front have not been legalized.
=== High-speed supernatant (HSS) === High-speed supernatant (HSS) is a fraction obtained by ultracentrifuging a conventional Xenopus egg extract at 100,000–200,000 × g, which removes membrane components and ribosomes, leaving a solution enriched in soluble proteins. Although HSS lacks the capacity to support nuclear assembly or protein translation, it can partially recapitulate chromatin structural changes in a cell cycle–dependent manner. It is particularly suitable for protein purification.
However, by 2025, relations had worsened, with US vice president JD Vance in February scolding "flimsy suspicions" and "enormous pressure from its continental neighbours" for causing the annulment of the 2024 Romanian presidential election in which Călin Georgescu won the first round. Relations with Moldova are a special case given that the two countries share the same language and a common history. A movement for unification of Moldova and Romania appeared in the early 1990s after both countries achieved emancipation from communist rule but lost ground in the mid-1990s when a new Moldovan government pursued an agenda towards preserving a Moldovan republic independent of Romania. After the 2009 protests in Moldova and the subsequent removal of Communists from power, relations between the two countries have improved considerably.
Sources: en.wikipedia.org
Tramadol, sold under the brand name Tramal among others, is an opioid pain medication and a serotonin–norepinephrine reuptake inhibitor (SNRI) used to treat moderate to severe pain. When taken by mouth in an immediate-release formulation, the onset of pain relief usually begins within an hour. It is also available by injection. It is available in combination with paracetamol (acetaminophen). As is typical of opioids, common side effects include constipation, itchiness, and nausea. Serious side effects may include hallucinations, seizures, increased risk of serotonin syndrome, decreased alertness, and drug addiction. A change in dosage may be recommended in those with kidney or liver problems. It is not recommended in those who are at risk of suicide or in those who are pregnant. While not recommended in women who are breastfeeding, those who take a single dose should not generally have to stop breastfeeding. Tramadol is converted in the liver to O-desmethyltramadol (desmetramadol), an opioid with a stronger affinity for the μ-opioid receptor. Tramadol was patented in 1972 and launched under the brand name Tramal in 1977 by the West German pharmaceutical company Grünenthal GmbH. In the mid-1990s, it was approved in the United Kingdom and the United States. It is available as a generic medication and marketed under many brand names worldwide. In 2023, it was the 36th most commonly prescribed medication in the United States, with more than 16 million prescriptions.
=== Pre-extinction diversity === Just before the K-Pg extinction event, the number of non-avian dinosaur species that existed globally has been estimated at between 628 and 1078. It remains uncertain whether the diversity of dinosaurs was in gradual decline before the K-Pg extinction event, or whether dinosaurs were actually thriving prior to the extinction. Rock formations from the Maastrichtian epoch, which directly preceded the extinction, have been found to have lower diversity than the preceding Campanian epoch, which led to the prevailing view of a long-term decline in diversity. However, these comparisons did not account either for varying preservation potential between rock units or for different extents of exploration and excavation. In 1984, Dale Russell carried out an analysis to account for these biases, and found no evidence of a decline; another analysis by David Fastovsky and colleagues in 2004 even showed that dinosaur diversity continually increased until the extinction, but this analysis has been rebutted. Since then, different approaches based on statistics and mathematical models have variously supported either a sudden extinction or a gradual decline. End-Cretaceous trends in diversity may have varied between dinosaur lineages: it has been suggested that sauropods were not in decline, while ornithischians and theropods were in decline.
=== Pricing and Profits === Throughout B.P.C. control, significant profits were made. In 1948, revenues from the island's phosphate reached $745,000. As the B.P.C. was controlled by its partner governments and was a major supplier of phosphate, it had an effective monopoly over the supply of phosphate to the markets in Australia and New Zealand, and could determine the price of phosphate delivered to those markets. The B.P.C. tied the pice for Ocean Island phosphate to the price paid for Nauru phosphate, however, the BPC would vary the price paid for phosphate. For example, around 1970, Nauru phosphate was sold to Japan at $14 and $15 a ton, but sold into the markets in Australia and New Zealand at $12.30.
Sources: en.wikipedia.org
It originated at the Institute of Molecular Genetics in Moscow during the 1980s. The work was carried out by a Russian research group that specialized in peptide neuropharmacology.
It is registered as a medicine in Russia and has been used clinically there for decades. No regulatory agency in Western Europe or North America has approved it for any indication.
Semax corresponds to the four-to-ten fragment of adrenocorticotropic hormone. Because it omits the first three residues, it lacks the adrenal-stimulating action of the full hormone.
一般不建议常温长期保存。多数说明指向 -20 °C 冷冻避光。常温运输通常被视为短期可接受，但会加快降解风险。