Everything below concerns Certificate of analysis. We keep the language plain, cite what the science says, and separate well-supported claims from open questions.
Updated 2025-11-21. Numbers and descriptions here follow the published literature rather than marketing material.
Characterization of Selank in laboratory settings relies on standard peptide analytical techniques. Reverse-phase high-performance liquid chromatography separates the peptide from related impurities and degradation products, while mass spectrometry confirms molecular identity through accurate mass measurement. Amino acid analysis and peptide sequencing verify the primary structure when reference material is unavailable. Because Selank is a short chain, fragmentation-based analysis produces a diagnostic ion pattern that supports confident identification.
Peptide stability depends strongly on temperature, moisture, and pH. Lyophilized Selank is generally most stable when stored cold and dry, with freezer temperatures commonly used for long-term storage. In solution, the compound is susceptible to hydrolysis and to microbial growth if it is not handled aseptically. The C-terminal proline-rich extension appears to slow enzymatic cleavage relative to tuftsin, though quantitative degradation rates vary with the matrix and the conditions tested. Published stability data specific to Selank remain sparse.
Quality assessment of Selank samples typically combines purity determination with identity confirmation and counter-ion analysis. Purity is usually reported as a percentage by chromatographic area, with values above 95 percent often quoted for research-grade material. Water content and residual solvents are checked in lyophilized batches because they affect both stability and accurate mass determination. A reported purity figure does not by itself establish that a sample is the intended sequence, so orthogonal methods are needed to rule out sequence isomers or truncation products.
Animal studies have examined behaviour in tests of anxiety, memory retention and stress response, and several report changes in neurotrophic or neurotransmitter-related markers. The human evidence base is much smaller, consisting mainly of short trials conducted in Russia with limited reporting in English-language journals. Sample sizes are modest and outcome measures vary between studies, so the findings are best described as preliminary. Independent replication under modern trial standards has not been widely reported.
Outside its country of origin the compound is generally handled as a research chemical rather than an approved medicine. No regulatory approval from the United States Food and Drug Administration or the European Medicines Agency has been granted for human use. Identity and purity are normally checked by reverse-phase high-performance liquid chromatography, with mass spectrometry used to confirm the molecular mass. Lyophilised material is stored cold and desiccated, and repeated freeze-thaw cycles are avoided.
Published work on this peptide almost always uses intranasal delivery, with drops or a spray applied to the nasal mucosa. Some animal experiments have used subcutaneous or intraperitoneal injection, and a smaller number have compared routes directly. Oral administration is not a focus of the literature, because short peptides of this size are broken down by digestive enzymes and cross intestinal barriers poorly. How much of an intranasal dose reaches the bloodstream intact in humans remains an open question.
| Property | Value | Notes |
|---|---|---|
| Typical storage temperature | -20 °C or below | For lyophilized powder, long term |
| Common analytical method | Reverse-phase HPLC | Usually paired with mass spectrometry |
| Typical reported purity | At or above 95 percent by area | Research-grade material |
| Aqueous solubility | High | Solutions used in laboratory assays |
| Moisture sensitivity | Hydrolyzes in solution | Aseptic handling reduces degradation |
Reported pharmacological effects center on reduced anxiety-like behavior in animal models and on measures of memory and learning. Proposed contributing mechanisms include modulation of GABAergic signaling, shifts in monoamine turnover, and changes in the activity of enzymes that degrade neuropeptides. Effects on the expression of genes linked to neuroplasticity have also been described. No single molecular target is widely accepted, and whether the behavioral findings arise from one pathway or several remains an open question.
Selank is a synthetic heptapeptide with the sequence Thr-Lys-Pro-Arg-Pro-Gly-Pro. It was designed as a stabilized analogue of tuftsin, a naturally occurring tetrapeptide fragment derived from the immunoglobulin heavy chain. The additional Pro-Gly-Pro segment at the carboxyl terminus is intended to slow enzymatic cleavage. The compound is usually described in the literature as a synthetic peptide with anxiolytic and cognitive-related activity, a label that reflects a research context rather than an approved therapeutic category.
Most published work on selank originates from a small number of research groups in the Russian Federation. A large share of that record appears in Russian-language journals, which limits access for readers who rely on English-indexed databases. Independent replication by laboratories outside the original research network is sparse in publicly available sources. This concentration of origin and language is a frequently noted feature when the compound is summarized in broader reviews of synthetic peptides.
Pharmacokinetic data are limited. Like most short peptides, Selank is vulnerable to plasma and tissue peptidases, and its measured half-life in circulation is short, on a minutes scale. The Pro-Gly-Pro tail slows this degradation but does not eliminate it. Intranasal administration is the route described in most reports, with absorption through the nasal mucosa and a hypothesized path into the central nervous system that avoids the blood-brain barrier. Direct measurements of human brain exposure are unavailable, so distribution claims rest on inference from animal work.
Clinical evidence comes mainly from small studies conducted in Russia, several of which were open-label or lacked robust blinding. Reported outcomes include lower anxiety scores, changes in attention measures, and effects on asthenic states following illness. Sample sizes are typically in the tens of participants, and independent replication outside the region is scarce. Reviews published in English generally note the limited methodological quality of the underlying trials. Whether the compound produces clinically meaningful effects under rigorous conditions remains unresolved.
2 Al + 3 S → Al2S3 This reaction is extremely exothermic and it is not necessary or desirable to heat the whole mass of the sulfur-aluminum mixture; (except possibly for very small amounts of reactants). The product will be created in a fused form; it reaches a temperature greater than 1,100 °C and may melt its way through steel. The cooled product is very hard.
== Endolithic parasitism == Until the 1990s phototrophic endoliths were thought of as somewhat benign, but evidence has since surfaced that phototrophic endoliths (primarily cyanobacteria) have infested 50 to 80% of midshore populations of the mussel species Perna perna located in South Africa. The infestation of phototrophic endoliths resulted in lethal and sub-lethal effects such as the decrease in strength of the mussel shells. Although the rate of thickening of the shells were faster in more infested areas it is not rapid enough to combat the degradation of the mussel shells.
Polypeptide directionality is similarly based on identifying the functional groups of amino acids, specifically the amino group, which forms the N-terminus, and the carboxyl group, which forms the C-terminus; amino acid sequences are assembled in the N-to-C direction during translation, and by convention are written in the same direction.
=== Pain === Morphine is used primarily to treat both acute and chronic severe pain. Its duration of analgesia is about three to seven hours. Side effects of nausea and constipation are rarely severe enough to warrant stopping treatment. It is used for pain due to myocardial infarction and for labor pains. However, concerns exist that morphine may increase mortality in the event of non-ST elevation myocardial infarction. Morphine has also traditionally been used in the treatment of acute pulmonary edema. However, a 2006 review found little evidence to support this practice. A 2016 Cochrane review concluded that morphine is effective in relieving cancer pain.
Sources: en.wikipedia.org
== Coding and Homology == The very first nucleotide sequence of the gene encoding for the beta subunit of human chorionic gonadotropin (CGB) suggests that CGB evolved from a duplicate copy of the beta subunit of LH, another glycoprotein hormone with significant influence over pregnancy, expressed in the anterior pituitary gland. Subsequent nuclear mapping has found that humans possess six copies of the CGB gene, amazingly found together with the LHB gene on chromosome 19q13.33. Human CGB and LHB genes share an extremely high degree of similarity in their sequences, clocking in at 94% similarity. This nucleotide sequence is encompassed by 3 exons. Of the six genes that encode for CGB, four of them are functional. These include CGB, CGB5, CGB7, and CGB8. These four genes share a 97-99% DNA sequence similarity, and code for the biochemically functional beta subunit of hCG. Although CGB1 and CGB2 genes are similar in sequence to the other four genes previously mentioned (85%), they encode for a novel hypothetical protein that is 132 amino acids in length and does not share any homology to the functional CGB subunit. This particular result was caused by a DNA fragment insertion into the 5' untranslated region (UTR) of the CGB1 and CGB2 genes, giving way to a novel exon one and creating a single basepair open reading frame shift for exons two and three.
Nike, Inc announces it will sell "limited quantities" of a replica goalkeeper shirt worn by England goalkeeper Mary Earps during the 2023 Women's World Cup after around 150,000 people signed an online petition calling for them to be made available. A police officer is taken to hospital with critical injuries after being hit by a train while trying to help a distressed man on the railway track in Nottinghamshire. 25 August – Hartwig Fischer announces he will step down as director of the British Museum after treasures were stolen from the London institution. 26 August – Two people are killed after driving a car into a flooded road in the Mossley Hill area of Liverpool. 27 August – The Metropolitan Police launch an investigation into a possible data breach involving details about thousands of their officers after "unauthorised access" was gained to the system of one of its suppliers. 29 August – Nottinghamshire Police officer Sgt Graham Saville, 46, who was struck by a train while trying to help a distressed man on the railway track, dies in hospital from injuries sustained in the incident. London's Ultra Low Emission Zone is expanded to include the whole of Greater London. 30 August – England's Autumn 2023 flu vaccination and COVID-19 booster programme is brought forward by a month, from October to September, as scientists from the UK Health Security Agency monitor the BA.2.86 variant. Although it is not a variant of concern, it is being monitored due to its high number of mutations.
=== 1880s === 1880: Self-taught German chemist Agnes Pockels began investigating surface tension, becoming a pioneering figure in the field of surface science. The measurement equipment she developed provided the basic foundation for modern quantitative analyses of surface films. 1880: Norwegian zoologist and malacologist Birgitte Esmark's publication on mollusks becomes the first time in Norway that a woman had a scientific work published. 1881: Italian scientists Evangelina Bottero and Carolina Magistrelli became the first women to achieve doctoral degrees in science in unified Italy. 1883: American ethnologist Erminnie A. Smith, the first female field ethnographer, published her collection of Iroquois legends Myths of the Iroquois. 1884: English zoologist Alice Johnson's paper on newt embryos became the first paper authored by a woman to appear in the Proceedings of the Royal Society. 1885: British naturalist Marian Farquharson became the first female Fellow of the Royal Microscopical Society. 1886: American botanist Emily Lovira Gregory became the first female member of the American Society of Naturalists. 1887: Rachel Lloyd became the first American woman to receive a PhD in chemistry, completing her research at the Swiss University of Zurich. 1888: Russian scientist Sofia Kovalevskaya discovered the Kovalevskaya top, one of a brief list of known rigid body motion examples that are tractable by manipulating equations by hand. 1888: Scottish astronomer Williamina Fleming discovered the Horsehead Nebula on a telescope-photogrammetry plate.
=== Ha === Fritz Haber (1868–1934), German chemist, 1918 Nobel Prize in Chemistry, father of the Haber process Dorothy Hahn (1876–1950), early American organic chemist and ultraviolet spectroscopist Otto Hahn (1879–1968), German chemist, discoverer of nuclear fission, 1944 Nobel Prize in Chemistry, father of nuclear chemistry Sossina M. Haile (born 1966), American chemist notable for developing the first solid acid fuel cells Naomi Halas (PhD 1987), American biochemist focusing on nanoshells and nanophotonics John Burdon Sanderson Haldane (1892–1962), British and Indian biochemist, geneticist and evolutionary biologist Charles Martin Hall (1863–1914), American chemist known for the Hall-Héroult process for inexpensive production of aluminum Frances Mary Hamer (1894–1980), British chemist who specialized in photographic sensitization compounds George S. Hammond (1921–2005), American chemist, famous for Hammond's postulate as part of the general theory of the transition state in chemical reactions Arthur Harden (1865–1940), English biochemist, Nobel Prize in Chemistry in 1929 for work on the fermentation of sugar and fermentative enzymes Elizabeth Hardy (1915–2008), Canadian-American chemist who discovered the Cope rearrangement of dienes Anna J.
Colomycin 1,000,000 units is 80 mg colistimethate; Coly-mycin M 150 mg colistin base is 360 mg colistimethate or 4,500,000 units. Because colistin was introduced into clinical practice over 50 years ago, it was never subject to the regulations that modern drugs are subject to, and therefore there is no standardised dosing of colistin and no detailed trials on pharmacology or pharmacokinetics. The optimal dosing of colistin for most infections is therefore unknown. Colomycin has a recommended intravenous dose of 1 to 2 million units three times daily for patients weighing 60 kg or more with normal renal function. Coly-Mycin has a recommended dose of 2.5 to 5 mg/kg colistin base a day, which is equivalent to 6 to 12 mg/kg colistimethate sodium per day. For a 60 kg man, therefore, the recommended dose for Colomycin is 240 to 480 mg of colistimethate sodium, yet the recommended dose for Coly-Mycin is 360 to 720 mg of colistimethate sodium. Likewise, the recommended "maximum" dose for each preparation is different (480 mg for Colomycin and 720 mg for Coly-Mycin). Each country has different generic preparations of colistin, and the recommended dose depends on the manufacturer. This complete absence of any regulation or standardisation of dose makes intravenous colistin dosing difficult for the physician. Colistin has been used in combination with rifampicin; evidence of in vitro synergy exists, and the combination has been used successfully in patients.
Sources: en.wikipedia.org
The most common approach combines reverse-phase liquid chromatography with mass spectrometry. Chromatography separates the components while mass spectrometry confirms the molecular mass. Peptide sequencing or tandem mass analysis can further verify the amino acid order.
Lyophilized powder is usually kept frozen and protected from moisture. Solutions are less stable and are often used promptly or divided into aliquots to avoid repeated freeze-thaw cycles. Exact shelf-life values depend on purity and handling.
No. A purity figure derived from chromatographic area does not prove the amino acid sequence. Identity requires an orthogonal method such as mass spectrometry or sequencing. Truncated or isomerized peptides can co-elute with the target compound.
Most published work uses intranasal application, either as drops or as a nasal spray. Injection routes appear in a smaller set of animal experiments. Oral use is uncommon in the literature because peptide breakdown and poor absorption limit this route.