Everything below concerns selank. We keep the language plain, cite what the science says, and separate well-supported claims from open questions.
Updated 2026-07-28. Numbers and descriptions here follow the published literature rather than marketing material.
Identity and purity are usually assessed by reversed-phase high-performance liquid chromatography, with mass spectrometry used to confirm molecular mass and sequence information. Amino acid analysis and peptide mapping may supplement these methods. Certified reference standards are scarce, and many commercial lots are sold as research chemicals without a pharmacopoeial monograph. Regulatory treatment differs by country: Selank is a registered prescription medicine in Russia, while in the European Union and the United States it is not an approved drug and may fall under research-chemical or unapproved-product frameworks.
Selank is a hydrophilic peptide and dissolves readily in water and in aqueous buffers. The lyophilised powder is typically a white to off-white solid. Because short peptides are prone to hydrolysis and oxidation, handling benefits from limiting exposure to heat, moisture and strong light. Working solutions are commonly prepared in sterile water or saline, and repeated freeze-thaw cycles are avoided to reduce aggregation and loss of activity. These practices reflect general laboratory convention rather than published stability specifications.
Dry powder is normally held at -20 degrees Celsius or lower, in a sealed container with desiccant and protection from light. Reconstituted solutions are usually kept at 2 to 8 degrees Celsius for short periods and frozen for longer ones. Proline residues at several positions are generally associated with some resistance to peptidase attack, but chemical stability still declines at neutral to alkaline pH and at elevated temperature. Exact shelf-life figures are product-specific and are not standardised across suppliers.
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.
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.
| Property | Value | Notes |
|---|---|---|
| Appearance | White to off-white powder | Lyophilised solid form |
| Solubility class | Freely soluble in water | Hydrophilic heptapeptide |
| Dry storage temperature | -20 degrees Celsius or lower | Sealed, desiccated, protected from light |
| Solution storage | 2 to 8 degrees Celsius short term | Avoid repeated freeze-thaw cycles |
| Common identification method | Reversed-phase HPLC with mass spectrometry | Confirms purity and molecular mass |
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.
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.
Lyophilized material is generally stable for extended periods when kept dry at or below minus twenty degrees Celsius. Working solutions are less stable, and common practice is to aliquot and freeze them so that repeated freeze-thaw cycles are avoided. Aqueous solutions are sensitive to pH extremes and to microbial growth, so short-term storage at refrigerator temperature is typical. Oxidation and hydrolysis are the principal degradation routes. Reconstitution with sterile water or a mild buffer is standard, and solutions should be protected from light.
Regulatory treatment varies by jurisdiction. In Russia the compound is a registered prescription product, while in the European Union and the United States it is generally handled as a research chemical without a marketing authorization. Suppliers therefore operate outside pharmaceutical oversight, and buyers rely on supplier documentation for purity and identity claims. Chain of custody and third-party testing are the main verification tools. Analysts note that the absence of a pharmacopoeial monograph for research-grade material limits standardization across vendors.
Handling follows standard practice for research peptides. Material is weighed in a low-humidity environment because the powder absorbs atmospheric moisture. Purity is reported as the percentage area of the main peak in a chromatogram, with specifications commonly set at 95 percent or higher; values below that threshold indicate the presence of truncated or modified species. Residual trifluoroacetate from purification is often present and may affect mass balance. Certificates of analysis should state the analytical method, the column and gradient used, and the lot-specific retention time so that results can be compared across suppliers.
Identity and purity of selank are established with reversed-phase high-performance liquid chromatography coupled to mass spectrometry. The peptide elutes from C18 columns with acetonitrile gradients in water containing trifluoroacetic acid or formic acid, and detection is usually performed by ultraviolet absorbance near 214 nm. Electrospray ionization in positive mode gives a doubly protonated ion near m/z 377, consistent with a mass of about 752 Da. Amino acid analysis or tandem mass spectrometry of fragment ions confirms the sequence. Because the molecule has no aromatic residues, it lacks a usable 280 nm chromophore, so low-wavelength detection or mass spectrometry is required.
Tuftsin, the parent structure, is a naturally occurring immunomodulatory tetrapeptide released from the Fc region of immunoglobulin G by spleen enzymes. Selank extends this four-residue sequence with three additional amino acids. The stated rationale is that the added tail slows enzymatic breakdown and may influence receptor interactions. How the full heptapeptide behaves at the molecular level is not firmly established, and proposed mechanisms often involve indirect modulation of neurotransmitter or immune signaling rather than a single defined target.
Selank is a synthetic heptapeptide developed in Russia. Its sequence is Thr-Lys-Pro-Arg-Pro-Gly-Pro, a seven-residue chain built around the natural tetrapeptide tuftsin. Researchers at the Institute of Molecular Genetics of the Russian Academy of Sciences first described the compound in the mid-1990s. The design combined the tuftsin core with an added Pro-Gly-Pro tail, a modification intended to extend the molecule's stability in biological fluids. Published work on the peptide has appeared mainly in Russian-language journals.
=== Labour Party organiser === Galloway joined the Labour Party Young Socialists aged 13, having falsely claimed to have been 15, and was still a teenager when he became secretary of the Dundee Labour Party. Galloway became vice-chairman of the Labour Party in the City of Dundee and a member of the Scottish Executive Committee in 1975. On 5 May 1977, he contested his first election campaign in the Scottish district elections, but failed to hold the safe Labour Gillburn ward in Dundee, being defeated by the independent Bunty Turley. He became the secretary organiser of the Dundee Labour Party in 1977, and at 26, was the youngest ever chairman of the Scottish Labour Party in March 1981, a post he held for a year, after holding the vice-chairman post over the previous year. After a trip to Beirut, Lebanon, during 1977, Galloway became a supporter of Palestine, stating during his libel case against The Daily Telegraph in 2004 that "barely a week after my return I made a pledge, in the Tavern Bar in Dundee's Hawkhill District, to devote the rest of my life to the Palestinian and Arab cause." He supported Dundee City Council when it flew the Palestinian flag over the City Chambers building, and was involved in the twinning of Dundee with the Palestinian West Bank town of Nablus in 1980. In late 1981, in an interview for the Scottish Marxist, Galloway supported the affiliation of the Communist Party of Great Britain (CPGB) to the Labour Party, in the same way as the Fabian Society does.
=== Social issues === In 2023, Celia Medrano described Bukele's positions on social issues as "flexible" ("flexibles") and a "liquid ideology" ("ideología líquida"). She explained that Bukele changes his positions to appease as many voters as possible and to gauge public opinion on issues such as same-sex marriage and abortion. Bukele stated in 2014 that he was an ally of the LGBT community, supported their civil rights, and opposed discrimination against LGBT individuals. In August 2021, Bukele proposed constitutional reform to legalize same-sex marriage in El Salvador. The proposal would have changed text in the constitution that defined marriage as being between "a man and a woman" ("hombre y mujer") to defining marriage as between "spouses" ("cónyuges"), and would have prohibited discrimination based on sexual orientation. The earliest Bukele's proposal could have gone into effect would have been 2027, since it would have to be approved by two consecutive sessions of the Legislative Assembly. Bukele stated the following month that the proposed constitutional reform would not legalize same-sex marriage, posting on Facebook that the original text would remain intact. In March 2024, Bukele stated that his government would remove "all traces" of "gender ideologies in schools and colleges". In June 2024, Bukele fired 300 bureaucrats from the ministry of culture for promoting policies that were "incompatible" with his emphasis on "patriotic and family values". El Salvador has one of the world's strictest abortion laws, banning it in all circumstances with no exceptions.
== Development == Valve developed Half-Life 2 (2004) over six years using its new game engine, Source. Instead of beginning work on a full sequel, Valve decided to create a series of episodic sequels. The designer Robin Walker said the team had become comfortable with their tools, and wanted to capitalize on their experience instead of developing new technologies. Valve's president, Gabe Newell, said customers would be happier with a new Half-Life game delivered in a shorter time rather than waiting years for another "monolithic product". In April 2005, Valve announced the game under the working title Aftermath. The title Episode One was announced in February 2006. In May, Valve announced that Episode One would be the first in a trilogy of episodic games to be released over the following two years. Newell said he considered the trilogy the equivalent of Half-Life 3. According to Newell, whereas the original Half-Life (1998) saw the G-Man transform Freeman into his tool, and Half-Life 2 saw Freeman being used by G-Man, the episodes would see G-Man lose control. While the plots and dialogue of Half-Life and Half-Life 2 were written solely by Marc Laidlaw, the Half-Life 2 episodes were written by Laidlaw and the new employees Chet Faliszek and Erik Wolpaw. Valve's focus was character development, particularly that of Gordon's companion Alyx, who accompanies the player for most of Episode One. Walker said it was ironic that the player spends most of Half-Life 2 alone despite the themes of "characters and other people".
=== Other Conditions === In individuals with primary hyperthyroidism, treatment via thyroid hormone therapy can reverse the hypertrophy and hyperplasia of the thyrotrophs. Individuals with a rare form of dwarfism characterized by hypothyroidism lack thyrotropic cells altogether, as this syndrome results from a mutation in the Pit-1 gene. Excess iodine present in individuals with Graves’ Disease can induce thyrotoxicosis, which is the overexpression of thyroid hormone. Sudden overexpression of the thyroid hormone is referred to as thyroid storm. Thyroid storm results in substantial decreases in the amount of thyrotropic cells in the pituitary gland. This decrease, if significant enough, can be fatal. However, with treatment, this decrease in the number of thyrotrophs can be reversed.
Sources: en.wikipedia.org
=== China === There are no regulations on beak trimming in the People's Republic of China. Some companies have decided to voluntarily phase out debeaking, such as Ningxia Xiaoming Farming and Animal Husbandry Co. Ltd.
=== Adhesion molecules of the immune system === Springer began his research career in immunology by studying the molecular basis for cellular immunity using as an example the interaction of cytotoxic T lymphocytes with antigen-bearing target cells. None of the molecules involved in this interaction had yet been defined, including the long postulated antigen-specific T cell receptor. However, it was known that Mg2+ was required for immune cell-cell interactions, and that interaction between fibroblasts and the extracellular matrix was similarly Mg2+-dependent. Postulating that adhesion receptors were likely to be similar to antibodies and were unlikely to require magnesium, Springer hypothesized that other molecules must be required for antigen-specific interactions. He immunized animals with cytotoxic T lymphocytes and screened for monoclonal antibodies that blocked antigen-specific killing. Using this functional assay, his laboratory identified a set of lymphocyte function-associated (LFA) antigens required for cytotoxic T-cell-mediated killing and other T cell-dependent responses, including LFA-1 (CD11a/CD18), LFA-2 (CD2), and LFA-3 (CD58). Springer's group then identified ICAM-1 as a ligand for LFA-1, demonstrating that this interaction is required for efficient antigen recognition by cytotoxic T cells, and later discovered ICAM-2 (CD102) and ICAM-3 (CD50), which have two to five immunoglobulin (Ig)-like domains and comprise a subfamily of the Ig superfamily.
Angiotensin-converting-enzyme inhibitors (ACE inhibitors) are a class of medication used primarily for the treatment of cardiovascular and kidney diseases. This class of medicine works by causing relaxation of blood vessels as well as a decrease in blood volume, which leads to lower blood pressure and decreased oxygen demand from the heart. ACE inhibitors inhibit the activity of angiotensin-converting enzyme, an important component of the renin–angiotensin system which converts angiotensin I to angiotensin II, and hydrolyzes bradykinin. Therefore, ACE inhibitors decrease the formation of angiotensin II, a vasoconstrictor, and increase the level of bradykinin, a peptide vasodilator. This combination is synergistic in lowering blood pressure. As a result of inhibiting the ACE enzyme in the bradykinin system, the ACE inhibitor drugs allow for increased levels of bradykinin which would normally be degraded. Bradykinin produces prostaglandin. This mechanism can explain the two most common side effects seen with ACE Inhibitors: angioedema and cough.
MT-ND6 is a gene of the mitochondrial genome coding for the NADH-ubiquinone oxidoreductase chain 6 protein (ND6). The ND6 protein is a subunit of NADH dehydrogenase (ubiquinone), which is located in the mitochondrial inner membrane and is the largest of the five complexes of the electron transport chain. Variations in the human MT-ND6 gene are associated with Leigh's syndrome, Leber's hereditary optic neuropathy (LHON) and dystonia.
=== Official discovery and later history === The discovery of element 43 was finally confirmed in a 1937 experiment at the University of Palermo in Sicily by Carlo Perrier and Emilio Segrè. In mid-1936, Segrè visited the United States, first Columbia University in New York and then the Lawrence Berkeley National Laboratory in California. He persuaded cyclotron inventor Ernest Lawrence to let him take back some discarded cyclotron parts that had become radioactive. Lawrence mailed him a molybdenum foil that had been part of the deflector in the cyclotron. Segrè enlisted his colleague Perrier to attempt to prove, through comparative chemistry, that the molybdenum activity was indeed from an element with the atomic number 43, which they did. University of Palermo officials wanted them to name their discovery panormium, after the Latin name for Palermo, Panormus. In 1947, element 43 was named after the Greek word technetos (τεχνητός), meaning 'artificial', since it was the first element to be artificially produced. Segrè returned to Berkeley and met Glenn T. Seaborg. They isolated the metastable isotope technetium-99m, which is now used in some ten million medical diagnostic procedures annually. In 1952, the astronomer Paul W. Merrill detected the spectral signature of technetium (specifically wavelengths of 403.1 nm, 423.8 nm, 426.2 nm, and 429.7 nm) in light from S-type red giants. The stars were near the end of their lives but were rich in the short-lived element, which indicated that it was being produced in the stars by nuclear reactions.
Sources: en.wikipedia.org
1 by the Minister, after consultation with such bodies representative of those interests as he may think fit, to represent the interests of persons (other than the British Transport Commission and any Executive) who are holders of A or B licences (within the meaning of Part IV of this Act) carrying on business within the London Traffic Area:† 1 by the Minister, after consultation with such bodies representative of those interests as he may think fit, to represent the interests of persons who are holders of C licences (within the meaning of Part IV of this Act) carrying on business within the London Traffic Area:† 1 by the Minister, after consultation with such bodies representative of those interests as he may think fit, to represent the interests of persons (other than the British Transport Commission and any Executive) who are the holders of licences authorising them to operate public service vehicles within the London Traffic Area: 1 by the Minister, after consultation with such bodies representative of those interests as he may think fit, to represent the interests of persons (other than the British Transport Commission and any Executive) providing or using horse-drawn road vehicles within the London Traffic Area. 1 by the Minister, after consultation with such bodies representative of those interests as he may think fit, to represent the interests of the taxi-cab industry within the London Traffic Area.
=== Parliaments of the Republic === 13th South African Parliament (1961–1966) – majority party: National Party 14th South African Parliament (1966–1970) – majority party: National Party 15th South African Parliament (1970–1974) – majority party: National Party 16th South African Parliament (1974–1977) – majority party: National Party 17th South African Parliament (1977–1981) – majority party: National Party 18th South African Parliament (1981–1984) – majority party: National Party 19th South African Parliament (1984–1987) – majority party: National Party 20th South African Parliament (1987–1989) – majority party: National Party 21st South African Parliament (1989–1994) – majority party: National Party
Breeding onset occurs at about 50 days of age in both females and males, although females may have their first estrus at 25–40 days. Mice are polyestrous and breed year round; ovulation is spontaneous. The duration of the estrous cycle is 4–5 days and lasts about 12 hours, occurring in the evening. Vaginal smears are useful in timed matings to determine the stage of the estrous cycle. Mating can be confirmed by the presence of a copulatory plug in the vagina up to 24 hours post-copulation. The presence of sperm on a vaginal smear is also a reliable indicator of mating. The average gestation period is 20 days. A fertile postpartum estrus occurs 14–24 hours following parturition, and simultaneous lactation and gestation prolongs gestation by 3–10 days, owing to delayed implantation. The average litter size is 10–12 during optimum production, but this is highly strain-dependent. In general, inbred mice tend to have longer gestation periods and smaller litters than outbred and hybrid mice. The young are called pups and weigh 0.5–1.5 g (0.018–0.053 oz) at birth, are hairless, and have closed eyelids and ears. Pups are weaned at 3 weeks of age, when they weigh about 10–12 g (0.35–0.42 oz). If the female does not mate during the postpartum estrus, she resumes cycling 2–5 days post-weaning. Newborn males are distinguished from newborn females by their greater anogenital distance and larger genital papilla. This is usually observed by lifting the tails of littermates and comparing perinea.
=== Poroelasticity === Poroelasticity is a characteristic of materials related to the migration of solvent through a porous material and the concurrent deformation that occurs. Poroelasticity in hydrated materials such as hydrogels occurs due to friction between the polymer and water as the water moves through the porous matrix upon compression. This causes a decrease in water pressure, which adds additional stress upon compression. Similar to viscoelasticity, this behavior is time dependent, thus poroelasticity is dependent on compression rate: a hydrogel shows softness upon slow compression, but fast compression makes the hydrogel stiffer. This phenomenon is due to the friction between the water and the porous matrix is proportional to the flow of water, which in turn is dependent on compression rate. Thus, a common way to measure poroelasticity is to do compression tests at varying compression rates. Pore size is an important factor in influencing poroelasticity. The Kozeny–Carman equation has been used to predict pore size by relating the pressure drop to the difference in stress between two compression rates. Poroelasticity is described by several coupled equations, thus there are few mechanical tests that relate directly to the poroelastic behavior of the material, thus more complicated tests such as indentation testing, numerical or computational models are utilized. Numerical or computational methods attempt to simulate the three dimensional permeability of the hydrogel network.
Sources: en.wikipedia.org
Dry powder is normally held at -20 degrees Celsius or below in a sealed, light-protected container with desiccant. Brief room-temperature handling during weighing is generally tolerated. Storage instructions vary between suppliers, so the accompanying certificate of analysis should be followed.
Reversed-phase HPLC establishes purity, while mass spectrometry confirms the expected molecular mass. Sequence confirmation may use tandem mass spectrometry or peptide mapping. A certificate of analysis typically reports these results alongside the analytical method applied.
In Russia it is a registered medicine available by prescription. In many other countries it is not approved for human use and is supplied only as a research chemical. Import and possession rules differ by jurisdiction, and buyers are responsible for checking local requirements.
Selank is a synthetic heptapeptide with the sequence Thr-Lys-Pro-Arg-Pro-Gly-Pro, designed as a metabolically stabilized analogue of the endogenous tetrapeptide tuftsin. It has been studied mainly against anxiety-related and cognitive endpoints rather than as an approved medicine in most jurisdictions.