The short version of proteolysis fits in a sentence. The long version — which is the one that helps — is below.
This page was last updated on 2026-07-18 and is reviewed periodically as new material appears.
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.
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 |
|---|---|---|
| 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 |
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.
Quantification in biological matrices relies on liquid chromatography coupled to tandem mass spectrometry with stable-isotope internal standards. Low plasma concentrations and adsorption to container surfaces both complicate measurement. Solid-phase extraction is often needed to reduce matrix interference before injection. Reported limits of quantification differ widely between laboratories, which makes direct comparison of pharmacokinetic results difficult and limits meta-analysis.
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.
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.
From 1948 to 1994, international rugby relations with apartheid South Africa, and also the non-integrated nature of rugby within the country drew frequent controversy. South Africa remained a member of the International Rugby Board (IRB) throughout the apartheid era. Halt All Racist Tours was established in New Zealand in 1969 to oppose continued tours to and from South Africa. Though contacts were restricted after the Gleneagles Agreement in 1977, there were controversial tours in 1980 by the British Lions and by France, in 1981 by Ireland, and in 1984 by England. South Africa toured New Zealand in 1981. South Africa were excluded from the first two Rugby World Cups, in 1987 and 1991. Racially selected New Zealand sports teams toured South Africa until the 1970 All Blacks rugby tour allowed Māori to go under the status of 'honorary whites'. The issue affected not only black South Africans, but also indigenous New Zealanders and to a lesser extent indigenous Australians. Many major rugby union international sides had few non-white players, but theoretically, a side such as Fiji would have been frowned upon. Apartheid South Africa's last foreign tour was to New Zealand in 1981, prior to the system's dismantlement in 1991 and new elections in 1994.
=== For evaluative well-being (life satisfaction) === Mental health is the strongest individual predictor of life satisfaction. Mental illness is associated with poorer well-being. In fact, mental health is the strongest determinant of quality of life at a later age. Studies have documented the relationship between anxiety and quality of life. The VOXEU analysis of happiness showed the principal determinants of an adult's life satisfaction to be income, parenting, family break up, mother's mental health and schooling. The factors that explain life satisfaction roughly map (negatively) to those factors that explain misery. They are first and foremost diagnosed depression/anxiety, which explains twice as much as the next factor, physical health (number of medical conditions), that explains just as much variance in subjective well-being between people, as income and whether someone is partnered. These factors count twice as much as each of whether someone is employed and whether they are a non-criminal, which in turn are 3 times as important as years of education. Overall, the best predictor of an adult's life satisfaction is their emotional health as a child as reported by the mother and child. It trumps factors like the qualifications that someone gets and their behaviour at 16 as reported by the mother. A child and therefore an adult's emotional health is most affected itself by a mother's mental health, which is just over twice as important as family income.
Jean Yee Hwa Yang is an Australian statistician known for her work on variance reduction for microarrays, and for inferring proteins from mass spectrometry data. Yang is a Professor in the School of Mathematics and Statistics at the University of Sydney.
Half-Life: Alyx received "universal acclaim", according to the review aggregator website Metacritic. According to the review aggregator OpenCritic, it was recommended by 97% of critics. By April 2020, it was one of the 20 highest-rated PC games on Metacritic. VG247, TechRadar and Video Games Chronicle described it as VR's "killer app". The announcement trailer was watched more than 10 million times within the first 24 hours of its release. Though most fans expressed excitement, some were disappointed that Alyx was only available in VR, a small but growing market in 2019. Vic Hood of TechRadar expressed enthusiasm but wrote that "we forever live in hope" for Half-Life 3. Kevin Webb of Business Insider wrote that Alyx could "spark fresh interest in an industry [VR] that has struggled to win over hardcore gamers". Andrew King of USGamer suggested that Alyx would test whether the modding community would embrace VR, a difficult area to work in. In IGN, Dan Stapleton wrote that Alyx was one of the best shooter games and the best VR shooter by far. He felt that Valve "set a new bar for VR in interactivity, detail, and level design ... It feels like a game from the future, and one that the rest of VR gaming will likely take a good long while to match, much less surpass." In Polygon, Ben Kuchera wrote of how Alyx transformed FPS systems. For example, he felt that reloading guns, traditionally performed with a button press, was more fun in VR. He wrote: "The magic lies in being inside the world, being able to touch it, and interact with it, directly.
via glucuronidation (30–50%): valproic acid β-O-glucuronide via beta oxidation (>40%): 2E-ene-valproic acid, 2Z-ene-valproic acid, 3-hydroxyvalproic acid, 3-oxovalproic acid via omega oxidation: 5-hydroxyvalproic acid, 2-propyl-glutaric acid some others: 3E-ene-valproic acid, 3Z-ene-valproic acid, 4-ene-valproic acid, 4-hydroxyvalproic acid All in all, over 20 metabolites are known. In adult patients taking valproate alone, 30–50% of an administered dose is excreted in urine as the glucuronide conjugate. The other major pathway in the metabolism of valproate is mitochondrial beta oxidation, which typically accounts for over 40% of an administered dose. Typically, less than 20% of an administered dose is eliminated by other oxidative mechanisms. Less than 3% of an administered dose of valproate is excreted unchanged (i.e., as valproate) in urine. Only a small amount is excreted via the faeces. Elimination half-life is 16±3 hours and can decrease to 4–9 hours when combined with enzyme inducers.
Sources: en.wikipedia.org
=== Francophone Affairs === Mulroney voted in support of the Ford government's September 2018 proposal to use Section 33 of the Canadian Charter of Rights and Freedoms, commonly called the "notwithstanding clause", to overrule a judge's decision that legislation intended to shrink the size of Toronto City Council was in fact in violation of Charter rights. For this position, she faced widespread condemnation from constitutional experts and politicians of all parties, particularly with respect to her duty to ensure the sanctity of the judicial process as Attorney General. In November 2018, Ford announced cuts which included cancelling a "French language university and cut the post of provincial commissioner for French language affairs." Ontario's francophone population represents from 550,000 to 744,000 people in a province of 14 million, according to The New York Times with many concentrated in Sudbury, Ontario, in northern Ontario and near the Ontario-Quebec border in eastern Ontario. The Ford government again came under criticism from the Franco-Ontarian community for its perceived inaction during the 2021 Laurentian University Financial Crisis and its support of the large cuts to the university.
== History == The Celloscope was developed for the Swedish company AB Lars Ljungberg & Co under the direction of engineer Erik Öhlin at Linson Instrument AB. In an interview published in the Clinical Biochemistry in the Nordics, a membership magazine for the Nordic Association for Clinical Chemistry, Lars Ljungberg explains that he and his coworkers had been considering different solutions for counting blood cells for some time when they came across a method presented by the American Navy on how particles could be counted when allowed to pass a capillary hole through which a weak direct current was passed simultaneously. The Celloscope method exploits the feature of blood cells not being conductive and therefore make interruptions (pulses) to the current, which then can be counted. What Ljungberg and coworkers did not know was that Wallace H. Coulter in Chicago had applied for and received a patent on the particle count principle in 1953. When presented at a German tradeshow in September 1957, the Celloscope counter was examined by Dr. George Brecher, the first author of one of the NIH evaluations of the Coulter counter. In a letter to Coulter, Brecher reported about what he thought was a close functional copy of the Coulter counter, yet with simpler electronics and an integrated sample stand, creating a both smaller and less costly instrument for use in clinical applications. When the Celloscope was introduced to the market in the early 60s, a lawsuit was filed by Coulter Electronics Inc. against AB Lars Ljungberg & Co for alleged infringement of the American patent.
(R(H)N)2CS + HgO → (RN)2C + HgS + H2O This reaction can often be conducted as stated, even though carbodiimides react with water. In some cases, a dehydrating agent is added to the reaction mixture. The dehydration of N,N'-dialkylureas gives carbodiimides:
=== Diet === Changes in diet may help prevent the development of atherosclerosis. Tentative evidence suggests that a diet containing dairy products has no effect on or decreases the risk of cardiovascular disease. A diet rich in fruits and vegetables lowers the risk of cardiovascular disease and death. Evidence suggests that the Mediterranean diet may improve cardiovascular results. There is also evidence that a Mediterranean diet may be better than a low-fat diet in bringing about long-term changes to cardiovascular risk factors (e.g., lower cholesterol level and blood pressure). A 2024 review highlighted that bioactive compounds found in Mediterranean diet components (such as olive, grape, garlic, rosemary, and saffron) exhibit properties that may contribute to cardiovascular health and atherosclerosis prevention.
== Collagen and accessory proteins == Almost all of the organic (non-mineral) component of bone is dense collagen type I, which forms dense crosslinked ropes that give bone its tensile strength. By mechanisms still unclear, osteoblasts secrete layers of oriented collagen, with the layers parallel to the long axis of the bone alternating with layers at right angles to the long axis of the bone every few micrometers. Defects in collagen type I cause the commonest inherited disorder of bone, called osteogenesis imperfecta. Minor, but important, amounts of small proteins, including osteocalcin and osteopontin, are secreted in bone's organic matrix. Osteocalcin is not expressed at significant concentrations except in bone, and thus osteocalcin is a specific marker for bone matrix synthesis. These proteins link organic and mineral component of bone matrix. The proteins are necessary for maximal matrix strength due to their intermediate localization between mineral and collagen. However, in mice where expression of osteocalcin or osteopontin was eliminated by targeted disruption of the respective genes (knockout mice), accumulation of mineral was not notably affected, indicating that organization of matrix is not significantly related to mineral transport.
Sources: en.wikipedia.org
Curium pnictides show ferromagnetic transitions upon cooling: 244CmN and 244CmAs at 109 K, 248CmP at 73 K and 248CmSb at 162 K. The lanthanide analog of curium, gadolinium, and its pnictides, also show magnetic transitions upon cooling, but the transition character is somewhat different: Gd and GdN become ferromagnetic, and GdP, GdAs and GdSb show antiferromagnetic ordering. In accordance with magnetic data, electrical resistivity of curium increases with temperature – about twice between 4 and 60 K – and then is nearly constant up to room temperature. There is a significant increase in resistivity over time (~10 μΩ·cm/h) due to self-damage of the crystal lattice by alpha decay. This makes uncertain the true resistivity of curium (~125 μΩ·cm). Curium's resistivity is similar to that of gadolinium, and the actinides plutonium and neptunium, but significantly higher than that of americium, uranium, polonium and thorium. Under ultraviolet illumination, curium(III) ions show strong and stable yellow-orange fluorescence with a maximum in the range of 590–640 nm depending on their environment. The fluorescence originates from the transitions from the first excited state 6D7/2 and the ground state 8S7/2. Analysis of this fluorescence allows monitoring interactions between Cm(III) ions in organic and inorganic complexes.
Technology companies have built electricity and artificial intelligence infrastructure to facilitate the AI boom of the 2020s. A 2025 report from the consulting firm McKinsey & Company estimated that by 2030, $2.7 trillion would be invested into AI infrastructure and data centres in the US, surpassing World War II's Manhattan Project every month. In January 2024, the International Energy Agency (IEA) released Electricity 2024, Analysis and Forecast to 2026. This is the first IEA report to make projections for data centres and power consumption by AI and cryptocurrency. The report states that power demand for these uses might double by 2026, with the additional power consumption equaling that of Japan. Power consumption by AI is responsible for an increase in fossil fuel use, and has delayed closings of obsolete, carbon-emitting coal energy facilities. A ChatGPT search involves 10 times as much electrical energy as a Google search. A 2024 Goldman Sachs research paper, AI Data Centers and the Coming US Power Demand Surge, found "US power demand (is) likely to experience growth not seen in a generation...." and forecasts that, by 2030, US data centres will consume 8% of US power, as opposed to 3% in 2022, presaging growth for the electrical power generation industry by a variety of means. Data centres' need for more and more electrical power is such that they might max out the electrical grid. The Big Tech companies counter that AI can be used to maximise the utilisation of the grid by all.
=== Prophecy === In Tales of the Green Lantern Corps Annual #2 (1986), a prophecy narrated to Abin Sur suggests that Mogo will be the last Green Lantern. In a battle with the "Empire of Tears", Ranx the Sentient City will explode a bomb in Mogo's core, killing him and ending the Green Lantern Corps. The Sinestro Corps attack Mogo with Ranx, who started to drill into the planet, with the intention of planting the blink bomb. It was revealed that Mogo is the one who guides the rings of deceased Lanterns to find new replacements and that if he should die, the Corps would be unable to recruit members in this manner. Thanks to the efforts of Sodam Yat, as well as a change in the Book of Oa permitting the Lanterns to use lethal force against the Sinestro Corps, Ranx is destroyed and the Sinestro Corps are driven from Mogo.
=== Hypersensitivity === Hypersensitivity is a rarely described but significant complication of parenteral nutrition therapy. First reported in 1965, the incidence of these reactions is speculated to be around one in 1.5 million patients who are provided parenteral nutrition. There is a wide range in how and when these reactions manifest. Cutaneous manifestations are the most common presentation. Hypersensitivity is thought to occur to the individual components of TPN, with the intravenous lipid emulsion being the most frequently implicated component, followed by the multivitamin solution and the amino acid solution. Medications Patients who are receiving intravenous parenteral nutrition may also need to receive intravenous medications as well using the same Y-site. It is important to assess the compatibility of the medications with the nutrition components. Incompatibilities can be observed physically through discoloration, phase separation, or precipitation.
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.