The short version of certificate of analysis fits in a sentence. The long version — which is the one that helps — is below.
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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.
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.
| Property | Value | Notes |
|---|---|---|
| Molecular formula | C33H57N11O9 | Derived from the seven-residue sequence |
| Molecular weight | About 751.9 g/mol | Average mass; the monoisotopic value is slightly lower |
| Residue count | Seven amino acids | Thr-Lys-Pro-Arg-Pro-Gly-Pro |
| Parent compound | Tuftsin (Thr-Lys-Pro-Arg) | Selank extends tuftsin at the C-terminus |
| Compound class | Synthetic short peptide | Studied in a research setting; not a licensed drug in most markets |
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.
Peptide bonds are vulnerable to protease attack, and Selank is no exception. Measured half-life in serum is short, on the order of minutes in several reports, which explains why intranasal administration is the common route described in the literature. Absorption across the nasal mucosa partially bypasses first-pass hepatic metabolism. Quantitative data on human bioavailability remain limited and are difficult to compare across studies.
Lyophilised material kept dry at minus 20 degrees Celsius or colder is the most stable form, and suppliers commonly state a shelf life of two years or more under those conditions. Once dissolved, degradation accelerates through hydrolysis and deamidation, particularly at alkaline pH or elevated temperature. Working solutions are usually divided into single-use aliquots to avoid repeated freeze-thaw cycles. The choice of reconstitution solvent affects both stability and the ionic strength of the final preparation.
Reverse-phase high-performance liquid chromatography with ultraviolet detection near 214 nanometres is the standard purity method. Mass spectrometry, typically electrospray ionisation, confirms identity through the expected mass-to-charge pattern. Amino acid analysis can verify composition independently. Chiral purity requires separate techniques such as derivatisation followed by chromatographic separation, and such data are rarely reported for research-grade material.
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.
Purity assessment relies mainly on reverse-phase high-performance liquid chromatography with ultraviolet detection. Because the peptide lacks a strong chromophore, detection often uses backbone absorbance near 214 nm. Identity is confirmed by mass spectrometry, typically electrospray ionization or matrix-assisted laser desorption, comparing the measured mass against the expected value. Amino acid analysis can verify composition after acid hydrolysis. Diastereomer content and residual counterions are reported less often, although both can influence biological assays.
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.
Development took place at the Institute of Molecular Genetics of the Russian Academy of Sciences, where a series of short peptides were designed in the 1980s and 1990s. Selank was selected from variants of tuftsin that showed resistance to plasma peptidases. Russian regulatory approval covers it as an anxiolytic agent given intranasally. Outside that market the compound is normally handled as a research chemical rather than a medicine, and no widely recognised international pharmacopoeial monograph exists. The name Selank is a coined trade designation rather than a systematic chemical name.
Enzymatic stability motivates the extra three residues at the carboxyl end. Native tuftsin is cleaved quickly by circulating aminopeptidases and carboxypeptidases, which limits its duration of action and its usefulness as a tool compound. Extending the chain with proline-rich segments is a common design tactic because proline constrains the backbone and slows proteolysis. The same Pro-Gly-Pro motif appears in other Russian-developed peptides of the era. Whether the full seven-residue chain is required for activity, or whether it acts mainly as a prodrug releasing tuftsin, remains unresolved.
== Synthesis and structure == With the formula Zn[(S2P(OR)2]2, zinc dithiophosphate features diverse R groups. Typically, R is a branched or linear alkyl between 1-14 carbons in length. Examples include 2-butyl, pentyl, hexyl, 1,3-dimethylbutyl, heptyl, octyl, isooctyl (2-ethylhexyl), 6-methylheptyl, 1-methylpropyl, dodecylphenyl, and others. A list of examples with their CAS numbers is here. Zinc dithiophosphate are often produced in two steps. First phosphorus pentasulfide is heated with suitable alcohols (ROH) to give the dithiophosphoric acid. A wide variety of alcohols can be employed, which allows the lipophilicity of the final zinc product to be fine tuned. The resulting dithiophosphoric acid is then neutralized, e.g., with ammonia or by adding zinc oxide:
Cytokinins are a class of plant hormones named for their control of cell division (especially cytokinesis). The natural cytokinin zeatin was discovered in corn, Zea mays, and is a derivative of the purine adenine. Zeatin is produced in roots and transported to shoots in the xylem where it promotes cell division, bud development, and the greening of chloroplasts. The gibberelins, such as gibberelic acid are diterpenes synthesised from acetyl CoA via the mevalonate pathway. They are involved in the promotion of germination and dormancy-breaking in seeds, in regulation of plant height by controlling stem elongation and the control of flowering. Abscisic acid (ABA) occurs in all land plants except liverworts, and is synthesised from carotenoids in the chloroplasts and other plastids. It inhibits cell division, promotes seed maturation, and dormancy, and promotes stomatal closure. It was so named because it was originally thought to control abscission. Ethylene is a gaseous hormone that is produced in all higher plant tissues from methionine. It is now known to be the hormone that stimulates or regulates fruit ripening and abscission, and it, or the synthetic growth regulator ethephon which is rapidly metabolised to produce ethylene, are used on industrial scale to promote ripening of cotton, pineapples and other climacteric crops.
== Biological activity == Cortisone is a corticosteroid, functioning as both a glucocorticoid and mineralocorticoid. Cortisone itself is inactive and instead acts as a prodrug or prohormone of cortisol (hydrocortisone), which is responsible for its biological activity. It is metabolized into cortisol via the actions of 11β-hydroxysteroid dehydrogenase 1 (11β-HSD1). Cortisol can also be metabolized back into cortisone by the actions of 11β-hydroxysteroid dehydrogenase 2 (11β-HSD2). Through conversion into cortisol, cortisone acts indirectly as an agonist of the corticosteroid receptors, including the glucocorticoid receptor (GR) and mineralocorticoid receptor (MR). In addition, through cortisol, it acts indirectly as an agonist of membrane corticosteroid receptors, including membrane glucocorticoid receptors (mGRs) and membrane mineralocorticoid receptors (mMRs). Cortisone has about 80% of the oral potency of hydrocortisone as both a glucocorticoid and mineralocorticoid when used clinically in humans. Relatedly, a dose of 25 mg cortisone is equivalent to about 20 mg hydrocortisone. In addition to its corticosteroid activity, cortisone has been reported to be a highly potent negative allosteric modulator of the GABAA receptor (1 pM–10 nM). This was demonstrated specifically in guinea pig ileum tissue.
== Properties == These enzymes are acid proteases; eqolisin for example is most active at pH 2.0 when casein is used as substrate. Eqolosins prefer bulky amino acid residues at the P1 site and small amino acid residues at the P1′ site. A characteristic of the protease is its insensitivity to pepstatin and S-PI (acetyl pepstatin) and it was previously classed as "pepstatin-insensitive carboxyl proteinases". The other "pepstatin-insensitive carboxyl proteinases" belongs to subfamily of serine protease, serine-carboxyl protease (sedolisin) which was discovered in 2001. These proteases are also not inhibited by DAN (diazoacetyl-DL-norleucine methylester) (7) but may be inhibited by EPNP (1,2-epoxy-3-(p-nitrophenoxy) propane).
Sources: en.wikipedia.org
== Solid waste == The World Bank collected data on the generation of municipal solid waste around the world. Of the ASEAN countries with data, Thailand's municipalities ranked number one in the region for waste generation at 1.76 kilograms per day per person. Others were Malaysia (1.52 kg/day); Singapore (1.49 kg/day); Vietnam (1.46 kg/day); Laos (0.70 kg/day); Indonesia (0.52 kg/day); Philippines (0.50 kg/day); Myanmar (0.44 kg/day). The World Bank projects that by 2025 Thailand's municipal generation of solid waste will reach 1.95 kg per person per day.
The electron density in cyanogen bromide is shifted away from the carbon atom, making it unusually electrophilic, and towards the more electronegative bromine and nitrogen. This leaves the carbon particularly vulnerable to attack by a nucleophile, and the cleavage reaction begins with a substitution reaction in which bromine is ultimately replaced by the sulfur in methionine. This attack is followed by the formation of a five-membered ring as opposed to a six-membered ring, which would entail the formation of a double bond in the ring between nitrogen and carbon. This double bond would result in a rigid ring conformation, thereby destabilizing the molecule. Thus, the five-membered ring is formed so that the double bond is outside the ring, as shown in the figure. Although the nucleophilic sulfur in methionine is responsible for attacking BrCN, the sulfur in cysteine does not behave similarly. If the sulfur in cysteine attacked cyanogen bromide, the bromide ion would deprotonate the cyanide adduct, leaving the sulfur uncharged and the beta carbon of the cysteine not electrophilic. The strongest electrophile would then be the cyanide carbon, which, if attacked by water, would yield cyanic acid and the original cysteine.
A new Familia 1000 coupé arrived in November 1965, with a 985 cc SOHC "PC" engine, and was joined by the larger Mazda Luce in 1966. Around the same time, the 800 engine was upgraded, adding three horsepower. As a number of new 1-litre vehicles were introduced by Mazda's competitors, another 987 cc OHV engine (PB) appeared in January 1967, powering new 1000 saloon and van versions. The 1-litre saloons and vans are recognizable by their broader, rounded-off rectangular headlights. Production of the saloon continued until November 1967, while the van versions continued until they were replaced in February 1968. Around 400,000 of the first Familias were built, 130,473 of which were saloons and coupés. Around 10,000 of the first generation Familias were exported, mainly to Australia and Oceania.
Sources: en.wikipedia.org
These were not ready until 1901, the year after the system first opened, and Guimard varied the "Métropolitain" lettering somewhat between stations and twice revised the design, which reached its final form in 1902.
=== Cardiovascular disease === Studies have elucidated different roles for LRP1 in cellular processes relevant for cardiovascular disease. Atherosclerosis is the primary cause of cardiovascular disease such as stroke and heart attacks. In the liver LRP1 is important for the removal of atherogenic lipoproteins (Chylomicron remnants, VLDL) and other proatherogenic ligands from the circulation. LRP1 has a cholesterol-independent role in atherosclerosis by modulating the activity and cellular localization of the PDGFR-β in vascular smooth muscle cells. Finally, LRP1 in macrophages has an effect on atherosclerosis through the modulation of the extracellular matrix and inflammatory responses. A 2026 analysis of human transcriptomic datasets found that LRP1 expression was highest in the aorta, followed by the coronary and tibial arteries, and was approximately twice as high in atrial tissue as in the left ventricle. Expression was generally stable with age except in the tibial artery, while sex differences among vascular tissues were detected only in the aorta. Single-cell data showed prominent expression in fibroblasts, macrophages, adipocytes, with moderate expression in smooth muscle cells.
== British and Commonwealth realms == In Commonwealth realms, including the United Kingdom, Canada, Australia and New Zealand, centenarians can receive congratulatory cards from the monarch, currently King Charles III, on their 100th birthday. In the UK, greeting cards are also sent by the monarch on every birthday beginning with the 105th. In Commonwealth realms in which the monarch does not ordinarily reside, honorees can also receive congratulations from the governor-general. In Canada, application must be made through the GGS official website. Similarly, in New Zealand, honorees must apply for greetings through the official government website.
== Cut anatomy and structure == The sirloin steak has several muscles that define the texture and flavor of different cuts. The sirloin does not do much work in supporting the cow, and so does not contain much reinforcing connective tissue. This makes the sirloin tender. The top sirloin primarily contains the Gluteus medius, along with the gluteus accessorius, gluteus profundus, and part of the biceps femoris. During butchery, these parts are separated along natural seams. These muscles differ in size and function. The gluteus medius is the largest and most prominent portion of the steak. These muscles contain connective tissue that contributes to differing tenderness between cuts. The gluteus medius cut is consistently tender. Heavily worked muscles, like the biceps femoris, are often firmer and more flavorful. The top sirloin cooks quicker than the bottom sirloin and is good for pan-searing and grilling. The bottom sirloin contains more muscles and is typically roasted or braised.
Sources: en.wikipedia.org
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.
Tuftsin contains four residues, while selank carries an additional Pro-Gly-Pro segment at the carboxyl end. That extension is intended to reduce enzymatic cleavage. Comparative pharmacokinetic data in humans remain limited.
No single receptor target is widely accepted as the definitive mediator of the reported effects. Proposed contributors include GABAergic modulation, shifts in monoamine turnover, and altered neuropeptide degradation. The mechanism is treated in the literature as unresolved.
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.