If you have been reading about lyophilised powder 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 2025-07-22. Where a claim depends on a specific study, the study is described rather than over-claimed.
Identity and purity are confirmed with reversed-phase high-performance liquid chromatography, typically monitored at 214 nanometres where the peptide bond absorbs. Mass spectrometry, either electrospray or MALDI-TOF, verifies molecular mass against the theoretical value and detects truncation or adduct formation. Amino acid analysis and peptide mapping provide additional confirmation when required. The most frequently reported impurities are deletion sequences from incomplete coupling, methionine sulfoxide from oxidation, and dimeric species formed through non-covalent aggregation. Impurity profiles depend strongly on the synthesis and purification route chosen by the producer.
Published research has focused mainly on neurological and cognitive endpoints in animal models, with proposed mechanisms involving brain-derived neurotrophic factor and related signalling pathways. A substantial share of the human data originates from a limited number of research groups, and independent replication in other countries remains sparse. Regulatory status reflects that distribution: the peptide is registered as a medicine in Russia and appears in some neighbouring markets, while elsewhere it is handled as a research chemical without approved therapeutic labelling. Questions about dose-response relationships, long-term effects, and comparability across studies are still open.
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。
| Property | Value | Notes |
|---|---|---|
| Purity assay | RP-HPLC, UV 214 nm | Typical research grade 95 percent or higher |
| Mass confirmation | ESI-MS or MALDI-TOF | Compared with theoretical value |
| Main degradation route | Methionine oxidation | Sulfoxide formation in solution |
| Powder storage | -20 °C, desiccated | Amber vial, minimal headspace |
| Working solution | Sterile water or saline | Prepare fresh; avoid repeated thawing |
Dissolution is normally performed in water, phosphate-buffered saline, or normal saline, since the peptide is freely soluble in aqueous media and is rarely handled with strong organic solvents. Solution pH should be kept near neutral, because extreme acidity or alkalinity accelerates backbone hydrolysis and encourages oxidation of the methionine side chain. Once dissolved, the material is less stable than the dry powder and is commonly divided into single-use portions and frozen. Buffers containing primary amines, such as Tris, are often avoided because of possible side reactions.
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.
Regulatory status differs sharply between jurisdictions. In Russia the peptide is registered as a prescription nasal preparation, while agencies such as the United States Food and Drug Administration have not approved it for any indication. Products sold elsewhere are typically labeled for laboratory research only, and such labels shift responsibility for safe handling to the purchaser. Because the same name covers pharmaceutical-grade nasal drops and bulk research powder, identity and purity documentation becomes the main practical concern when comparing sources.
Semax is a synthetic seven-amino-acid peptide whose sequence extends the ACTH(4-10) fragment with a C-terminal proline-glycine-proline tripeptide. The commonly cited sequence is Met-Glu-His-Phe-Pro-Gly-Pro, giving a molecular formula near C37H51N9O10S and a molecular weight close to 813.9 g/mol. It belongs to the broader class of synthetic ACTH fragments studied for central nervous system effects rather than for adrenal steroid stimulation. In practice the material appears as a lyophilized white powder for laboratory work or as a dilute saline solution in clinical settings.
Development is attributed to researchers at the Institute of Molecular Genetics in Moscow during the early 1980s, building on earlier Soviet work with ACTH fragments. Russian regulatory approval followed for intranasal use, and the compound has remained commercially available there for decades. Most published human data originate from Russian and, later, some Eastern European clinical reports, which are not always accessible in English translation. Outside that region the material is generally handled as a research chemical rather than a licensed medicine.
==== National honors ==== Knight Grand Cross of Rizal (KGCR) – (2017) Awards for Promoting Philippines-China Understanding (APPCU), Hall of Fame – (2023) Integrated Bar of the Philippines Golden Pillar of Law Award – (2025)
The English name of "Singapore" is an anglicisation of the native Malay name for the country, Singapura (Malay pronunciation: [siŋapura] ), which was in turn derived from the Sanskrit word for 'lion city' (Sanskrit: सिंहपुर; romanised: Siṃhapura; Brahmi: 𑀲𑀺𑀁𑀳𑀧𑀼𑀭; literally "lion city"; siṃha means 'lion', pura means 'city' or 'fortress'). Pulau Ujong was one of the earliest names for the island of Singapore, which corresponds to a Chinese account from the third century referred to a place as Pú Luó Zhōng (Chinese: 蒲 羅 中), a transcription of the Malay name for 'island at the end of a peninsula'. Early references to the name Temasek (or Tumasik) are found in the Nagarakretagama, a Javanese eulogy written in 1365, and a Vietnamese source from the same time period. The name possibly means Sea Town, being derived from the Malay tasek, meaning 'sea' or 'lake'. The Chinese traveller Wang Dayuan visited a place around 1330 named Danmaxi (Chinese: 淡馬錫; pinyin: Dànmǎxí; Wade–Giles: Tan Ma Hsi) or Tam ma siak, depending on pronunciation; this may be a transcription of Temasek, alternatively, it may be a combination of the Malay Tanah meaning 'land' and Chinese xi meaning 'tin', which was traded on the island. Variations of the name Siṃhapura were used for a number of cities throughout the region prior to the establishment of the Kingdom of Singapura. In Hindu–Buddhist culture, lions were associated with power and protection, which may explain the attraction of such a name.
The mucosa is the innermost layer of the gastrointestinal tract. The mucosa surrounds the lumen, or open space within the tube. This layer comes in direct contact with digested food (chyme). The mucosa is made up of:
To demonstrate just how deadly this species is, an estimate was made on the number of mice and adult human fatalities it is capable of causing in a single bite that yields the maximum dose of 400 mg. Based on the study by Ernst and Zug et al. 1996, which listed the LD50 of the coastal taipan at 0.106 mg SC and a venom yield of 400 mg, this would be sufficient to kill 208,019 mice and 59 adult humans in a single bite that delivers 400 mg of venom. The venom apparatus of this species is well developed. The fangs are the longest of any Australian elapid snake, being up to 1.2 cm (0.5 in) long, and are able to be brought forward slightly when a strike is contemplated. Coastal taipans can inject large amounts of highly toxic venom deep into the tissue. Its venom contains primarily taicatoxin, a highly potent neurotoxin known to cause hemolytic and coagulopathic reactions. The venom affects the nervous system and the blood's ability to clot, and bite victims may experience headache, nausea and vomiting, collapse, convulsions (especially in children), paralysis, internal bleeding, myolysis (destruction of muscle tissue) and kidney damage. In a single study done in Papua New Guinea, 166 patients with enzyme immunoassay-proven bites by Papuan taipans (Oxyuranus scutellatus canni) were studied in Port Moresby, Papua New Guinea. Of the 166 bite victims, 139 (84%) showed clinical evidence of envenoming: local signs were trivial, but the majority developed hemostatic disorders and neurotoxicity.
=== Czech Republic === A member of Parliament is a member of either of the two chambers of the Parliament of the Czech Republic, although the term member of Parliament of the Czech Republic is commonly referred to as deputy of the Parliament of the Czech Republic (Czech: Poslanec Parlamentu České republiky), who is a member of the lower house of the Parliament, the Chamber of Deputies. For the upper house, the Senate, the term senator is used.
Sources: en.wikipedia.org
Research suggests that during reproduction, fungal spores from X. parietina may engage in a form of reproductive parasitism (a type of symbiosis where a microorganism alters the reproduction of a host) by "stealing" algal partners from Physcia lichens, which contain the same algal species. This algal sharing strategy provides a reproductive advantage, as germinating X. parietina fungal spores can bypass the uncertain process of finding compatible free-living algae. However, the species engages in a long-term ecological succession pattern. Studies tracking lichen communities over five-year periods found that Physcia species (such as P. adscendens and P. caesia) are comparatively short-lived, typically developing and vanishing within about two years, while X. parietina populations persisted throughout. Eventually, in sheltered or humid locations, bryophytes (particularly Orthotrichum species) tend to invade and overgrow lichen-covered surfaces—representing the normal succession pattern in canopy situations. The regenerative capacity of X. parietina allows it to maintain its presence longer than many other lichen species during this successional process, but it is eventually replaced by vigorously growing mosses in most sheltered habitats.
== Further reading == Brayden DJ (November 2022). "Localised Delivery of Macromolecules to the Large Intestine: Translation to Clinical Trials". BioDrugs. 36 (6): 687–700. doi:10.1007/s40259-022-00562-6. PMID 36282433. S2CID 253109130.</ref> Fourie A, Cheng X, Chang L, Greving C, Patrick A, Knight B, et al. (October 2023). "S1028 Characterization of a First-in-Class Oral Therapy Selectively Targeting the IL-23 Pathway". American Journal of Gastroenterology. 118 (10S): S781. doi:10.14309/01.ajg.0000953752.29003.56. Ghusn W, Gala K, Rahme SJ, Salame M, Mrad R, Abboud DM, et al. (October 2023). "S1029 Disparities in Age, Sex, Race, and Ethnicity in Clinical Trials Focused on Inflammatory Bowel Disease in the United States". American Journal of Gastroenterology. 118 (10S): S781–S782. doi:10.14309/01.ajg.0000953756.85659.9e. Rusiñol L, Carmona-Rocha E, Puig L (3 July 2023). "Psoriasis: a focus on upcoming oral formulations". Expert Opinion on Investigational Drugs. 32 (7): 583–600. doi:10.1080/13543784.2023.2242767. PMID 37507233. S2CID 260286273.
== Languages == Moluccans speak over a hundred different languages, with a majority of them belonging to the Central Malayo-Polynesian language family. An important exception is the North Moluccan islands which include the island of Halmahera and its surrounding islands, where the majority of the population speak West Papuan languages (North Halmahera branch), possibly brought through historical migration from the Bird's Head Peninsula of New Guinea. Another exception are the Malay-based creoles such as the Ambonese language (also known as Ambonese Malay), spoken mainly on Ambon and the nearby Ceram; and North Moluccan Malay used on the islands of Ternate, Tidore, Halmahera and Sula Islands in North Maluku. Moluccans living in the Netherlands mostly speak Ambonese and Buru, as well as the national and official Dutch language.
The Russian Partition (Polish: zabór rosyjski) constituted the former territories of the Polish–Lithuanian Commonwealth that were annexed by the Russian Empire in the course of late-18th-century Partitions of Poland. The Russian acquisition encompassed the largest share of the Polish–Lithuanian Commonwealth's population, living on 463,200 km2 (178,800 sq mi) of land constituting the eastern and central territory of the former Commonwealth. The three partitions, which took place in 1772, 1793 and 1795, resulted in the complete loss of Poland's and Lithuania's sovereignty, with their territories split between Russia, Prussia and Austria. The majority of Lithuania's former territory was annexed by the Russian Empire, except for Užnemunė (a geographical area on the left bank of the River Neman) which was annexed by Prussia. The Napoleonic Wars saw significant parts of Prussia's and Austria's partitions reconstituted as the Duchy of Warsaw (a French client state in a personal union under Saxony), most of which was then reconstituted as the Kingdom of Poland within the Russian Empire in 1815.
=== PCR method === PCR-based screening methodologies are in the process of development for a number of genes responsible for resistance. They speed up detection and can readily differentiate between carbapenamase genes-sometimes in a multiplex format. Costs of PCR testing are decreasing and reliability of molecular based tests relates more to gene presence and gene expression for production of the relevant carbapenamase. Nested arbitrary PCR (ARB-PCR) was used during a 2007 CRE outbreak at the University of Virginia Medical Center to identify the specific bla KPC plasmid involved in the transmission of the infection, and researchers suggest that ARB-PCR may also be used to identify other methods of CRE spread.
Sources: en.wikipedia.org
== Discovery == The first descriptions of the MHC were made by British immunologist Peter Gorer in 1936. MHC genes were first identified in inbred mice strains. Clarence Little transplanted tumors across different strains and found rejection of transplanted tumors according to strains of host versus donor. George Snell selectively bred two mouse strains, attained a new strain nearly identical to one of the progenitor strains, but differing crucially in histocompatibility—that is, tissue compatibility upon transplantation—and thereupon identified an MHC locus. Later Jean Dausset demonstrated the existence of MHC genes in humans and described the first human leucocyte antigen, the protein which we call now HLA-A2. Some years later Baruj Benacerraf showed that polymorphic MHC genes not only determine an individual's unique constitution of antigens but also regulate the interaction among the various cells of the immunological system. These three scientists have been awarded the 1980 Nobel Prize in Physiology or Medicine for their discoveries concerning "genetically determined structures on the cell surface that regulate immunological reactions". The first fully sequenced and annotated MHC was published for humans in 1999 by a consortium of sequencing centers from the UK, USA and Japan in Nature. It was a "virtual MHC" since it was a mosaic from different individuals. A much shorter MHC locus from chickens was published in the same issue of Nature. Many other species have been sequenced and the evolution of the MHC was studied, e.g.
In 2019, Mahathir said that Malaysians should learn from the hard work of China's citizens, which enabled their nation to achieve technological advancement within a few decades. In 2025, he said that China would overtake the United States and remain the world's top power in the long term, while downplaying India's potential to compete with China on a global scale. Mahathir has advocated for a balance between environmental protection and natural resource use for economic growth in developing countries. He referred to the outcomes of the Earth Summit as "eco-imperialism", arguing that Global North countries put an undue burden on Global South countries for environmental degradation. In response to international scrutiny, he said in 2019 that linking palm oil production to deforestation was "baseless, unfair and unjustified" and that the Malaysian palm oil sector had developed sustainably. In the aftermath of the 2020 Nice stabbing and murder of Samuel Paty, Mahathir posted remarks on his blog. Mahathir said that the attacks were wrong and against Islam, but also argued that Muslims had a right to be angry and kill French people for past massacres committed by the French. Mahathir's post was later circulated on his Twitter account, where it was labelled for "glorifying violence". Mahathir was criticised for stoking tensions and hatred by the former Australian ambassador to France Brendan Berne, Australian prime minister Scott Morrison, and French secretary of state for digital affairs Cédric O.
DNA → RNA → protein Some critics thought that by using the word "dogma", Crick was implying that this was a rule that could not be questioned, but all he really meant was that it was a compelling idea without much solid evidence to support it. In his thinking about the biological processes linking DNA genes to proteins, Crick made explicit the distinction between the materials involved, the energy required, and the information flow. Crick was focused on this third component (information) and it became the organising principle of what became known as molecular biology. Crick had by this time become a highly influential theoretical molecular biologist. Proof that the genetic code is a degenerate triplet code finally came from genetics experiments, some of which were performed by Crick. The details of the code came mostly from work by Marshall Nirenberg and others who synthesised synthetic RNA molecules and used them as templates for in vitro protein synthesis. Nirenberg first announced his results to a small audience in Moscow at a 1961 conference. Crick's reaction was to invite Nirenberg to deliver his talk to a larger audience.
His plan fails and he rejoins Freeman's group. Freeman then finds Bubby stuck in his old test tube, who had also been betrayed by the military, along with Benry. Freeman reluctantly allows them to rejoin the group. The science team proceed to Black Mesa's Mixology Department, headed by Darnold (Logmore), who gives Freeman a potion that causes his missing arm to regrow into a machine gun. The team fight their way to the Lambda Complex, where they teleport to Xen. In Xen, they find Benry has grown into a giant and begins floating around the others, taunting them. Benry is revealed to be the source of the resonance cascade, transforming into a monstrous alien form and attacking the rest of the science team, who work together to eventually defeat him, by time traveling to the beginning of the game to retrieve their passports. After defeating Benry, Freeman is captured by the G-Man (Spaghoner), who thanks him for taking down Benry and invites him to the birthday party of Tommy, revealed to be the G-Man's adopted son. In the credits sequence, the science team and the G-Man celebrate Tommy's birthday at a Chuck E. Cheese, much to Freeman's despair. In a post-credits scene, Dr. Coomer calls Freeman and congratulates him for beating the game, thanking him for taking the science team with him on his adventure.
Estradiol can be administered in a very long-lasting form via subcutaneous implantation of pure crystalline estradiol compressed into a small solid cylindrical pellet. These pellets slowly and completely dissolve and are replaced once every 6 to 12 months, achieving high and very constant circulating levels of estradiol. They are surgically inserted with the aid of a trocar by a trained physician in a medical office or clinic, and can be placed into locations including the lower abdomen, lower back, buttocks, or hips. Subcutaneous pellets containing 20 mg estradiol (brand name Meno-Implant) or 25, 50, or 100 mg estradiol (brand name Estradiol Implants; discontinued) for replacement usually once every 6 months (range 4 to 8 months) are or have been available as approved pharmaceutical medications. Up to 800 mg estradiol per implantation has been used. Pharmaceutical estradiol pellet implants have been used almost exclusively in the United Kingdom, but have also been available in Australia and the Netherlands. However, estradiol pellets have been discontinued in both the United Kingdom and Australia. An estradiol implant has not been approved by the FDA as a pharmaceutical medication in the United States, but hormone pellet implants, including estradiol pellets, are available as custom compounded products in this country. Estradiol pellet implants are advantageous in that some women seem to need higher levels of estradiol for adequate relief of menopausal symptoms, and subcutaneous estradiol pellets are easily able to achieve such levels.
Sources: en.wikipedia.org
Reversed-phase HPLC gives the main purity figure, most often with UV detection near 214 nanometres. Mass spectrometry then confirms the molecular mass. Together the two methods distinguish a correct sequence from a closely related impurity.
The main chemical risks are methionine oxidation and backbone hydrolysis in solution. Moisture and repeated temperature cycling accelerate both processes. Dry powder held cold and desiccated is considerably more stable than any reconstituted preparation.
It holds a medicine registration in Russia, where it has been used clinically for decades. In most other countries it is treated as a research chemical. That split explains the uneven distribution of clinical literature.
不存在。它是依据 ACTH 的一段序列人工设计的分子，天然蛋白质中找不到与之完全相同的七肽。名称属于研究代号，而非天然物质名。