mass spectrometry raises a handful of sensible questions. This page answers them in order, starting with the fundamentals and moving to applications.
Reviewed 2026-03-18. Anything still debated is marked as such rather than presented as settled.
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.
Selank is a synthetic heptapeptide with the sequence Thr-Lys-Pro-Arg-Pro-Gly-Pro. Its four N-terminal residues reproduce tuftsin, a tetrapeptide fragment of the immunoglobulin heavy chain, while the C-terminal Pro-Gly-Pro extension is a synthetic addition. The peptide has a molecular mass near 752 daltons and carries a net positive charge at physiological pH because of the arginine and lysine side chains. Published indexes list it under the name Selank and the sequence abbreviation TKPRPGP. Solid-phase peptide synthesis is the standard production route for research quantities.
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.
| Property | Value | Notes |
|---|---|---|
| Chemical class | Synthetic heptapeptide | Tuftsin analogue with a C-terminal Pro-Gly-Pro tail |
| Amino acid sequence | Thr-Lys-Pro-Arg-Pro-Gly-Pro | Abbreviated TKPRPGP in most catalogues |
| Molecular mass | About 752 Da | Value for the free peptide |
| Solubility | Freely soluble in water | Aqueous solutions are kept cold and used promptly |
| Typical storage | -20 °C, dry, protected from light | Applies to the lyophilised powder before reconstitution |
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.
Proposed mechanisms center on modulation of the GABA system, but no single molecular target has been confirmed. Rodent studies report changes in GABA-A receptor expression and in the turnover of serotonin, dopamine, and norepinephrine in several brain regions. Increases in brain-derived neurotrophic factor and its receptor have also been described after repeated administration. These findings come largely from animal models, and the degree to which they describe human neurochemistry remains an open question. The mechanism is best characterized as multi-system and not fully resolved.
Solubility behavior is a practical concern for handling. Selank dissolves readily in water and in common aqueous buffers, which simplifies preparation of working solutions. The choice of solvent, ionic strength, and pH can influence aggregation over time, particularly at higher concentrations. Aqueous solutions are typically sterile-filtered before use. Because stability depends on several variables, storage and handling notes should be treated as general guidance rather than fixed rules, and specific values are best confirmed against a certificate of analysis for each batch.
Characterization of Selank in a laboratory setting relies on standard peptide methods. Reverse-phase high-performance liquid chromatography separates the target from related impurities and provides a purity figure, commonly reported as 95 percent or higher. Mass spectrometry, typically electrospray ionization or matrix-assisted laser desorption, confirms the molecular mass and helps detect truncation or modification. Amino acid analysis can verify composition when a sequence-level check is needed. These techniques together establish identity and purity for a given lot.
Lyophilized Selank, the dry powder form, is generally stored frozen at minus 20 degrees Celsius or colder for long-term keeping. The solid is hygroscopic and should stay sealed, dry, and protected from light. Once dissolved, the peptide is less stable and is usually held refrigerated at 2 to 8 degrees Celsius for short periods. Repeated freezing and thawing is avoided because it can promote aggregation and loss of activity. Buffers and pH choice also affect how long a solution remains usable.
Published clinical work is concentrated in Russian-language journals and generally involves small samples without independent replication. Systematic reviews in English note the shortage of randomised, placebo-controlled trials and the difficulty of verifying methods from translated reports. Outcome measures vary between studies, which complicates pooling of results. Interest in the compound as a cognitive or anxiolytic agent therefore rests on a thinner evidence base than the volume of citations suggests. Replication in well-powered trials with preregistered endpoints would be needed before firm conclusions about efficacy can be drawn.
Proposed mechanisms centre on the GABAergic system. Animal and tissue studies report changes in GABA-A receptor expression and reduced activity of GABA transaminase, the enzyme that degrades GABA. Effects on monoamine turnover, including serotonin and dopamine pathways, are also described, and a separate line of work links the peptide to increased expression of brain-derived neurotrophic factor in hippocampal tissue. Most of these findings come from rodent models and cell preparations. How the individual observations combine into a single coherent mode of action is not settled.
The compound has a calculated molecular weight near 751.9 daltons and carries a net positive charge at physiological pH because of its arginine residue. It dissolves freely in water and in common aqueous buffers, and typically appears as a white or off-white lyophilized powder. The amide backbone makes the molecule susceptible to peptidases, which limits oral use and favors intranasal or parenteral routes. Nomenclature in the literature varies: the substance is also described by the sequence abbreviation TP-7 and by a Russian trade designation.
Regulatory status differs sharply by region. Selank holds a Russian marketing authorization, where it is supplied mainly as nasal drops, while authorities elsewhere have not approved it for medical use. Material sold internationally is therefore usually labeled as a research chemical rather than a medicine. Peer-reviewed publications come predominantly from Russian laboratories, and sample sizes are generally small. Whether the compound produces comparable effects under independent, well-controlled replication remains an open question that the broader literature has not settled.
Selank is a synthetic heptapeptide developed in Russia as a structural analogue of tuftsin, a naturally occurring immunomodulatory tetrapeptide. Its sequence, Thr-Lys-Pro-Arg-Pro-Gly-Pro, keeps the tuftsin core at the N-terminus and appends a Pro-Gly-Pro tail. Researchers at the Institute of Molecular Genetics in Moscow synthesized the compound during the 1990s while searching for peptides with combined anxiolytic and immunomodulatory activity. The added tail was intended to resist enzymatic cleavage and prolong the molecule's presence in circulation.
=== Separation of powers === On 24 October, the Sudanese Professionals Association (SPA) claimed that civilian members of the Sovereignty Council violated the constitutional constraints on their power by appearing to coordinate with Rapid Support Forces (RSF) and override the Ministry of Health's role in managing vector control against the spread of dengue fever and chikungunya. The SPA stated, "the campaign appeared to be the scene of direct interaction of the [RSF] with the health situation in the concerned states, in the absence of health departments at the federal or state level. ... [The] whole issue of health is not the prerogative of the Sovereign Council." Sudan Tribune expressed concern that the RSF and its leader Hemedti were trying to improve the RSF's image, damaged by its carrying out of crimes against humanity in the War in Darfur and human rights violations during the 3 June 2019 Khartoum massacre.
== Human sexual orientation and behavior genetics == In the 1990s Hamer began studies on the genetics of human behavior, which led to the first molecular evidence for genes that influence human sexual orientation. His research group's first paper, published in Science in 1993, reported that the maternal but not paternal male relatives of gay men had increased rates of same-sex orientation, suggesting the possibility of sex-linked transmission in a portion of the population. A genetic linkage analysis of DNA samples from these families showed that gay brothers had an increased probability of sharing polymorphic markers on the subtelomeric region of the long arm of the X chromosome, Xq28, providing statistically significant evidence for linkage to the sexual orientation phenotype. This finding was replicated in two other studies in the United States whereas a study in Canada found contrary results; meta-analysis of all data available at that time suggested that Xq28 has a significant but not exclusive effect. Subsequently, a genomewide scan by Hamerʻs group revealed additional regions on autosomes that were moderately linked to male sexual orientation. Hamer's results were supported in 2014 in a large, multi-center genetic linkage study of male sexual orientation. This study's analysis of 409 pairs of gay brothers with over 300,000 single-nucleotide polymorphism markers confirmed the Xq28 linkage by two-point and multipoint LOD score mapping.
=== Squadrons === 22 SAS normally has a strength of 400 to 600. The regiment has four operational squadrons: A, B, D and G. Each squadron consists of approximately 65 members commanded by a major, divided into four troops (each troop being commanded by a captain) and a small headquarters section. Troops usually consist of 16 members. Members of the SAS are variously known as "blade" or "operator". Each patrol within a troop consists of four members, with each member possessing a particular skill e.g. signals, demolition, medic or linguist in addition to basic skills learned during the course of his training. The term "squadron" dates back to the unit's earliest days when the unit's name was intended to confuse German intelligence. The four troops specialise in four different areas:
Sources: en.wikipedia.org
== Proteins and peptides == Some prominent examples of transition metal complexes of carboxamido (deprotonated carboxamide) ligands: bleomycin (Fe), Nickel superoxide dismutase (Ni), and nitrile hydratase (Co).
The Kardashev scale (Russian: шкала Кардашёва, romanized: shkala Kardashova) is a method of measuring a civilization's level of technological advancement based on the amount of energy it is capable of harnessing and using. As both a proposed method of tracking civilizational progress and a way to evaluate potential alien civilizations, it occupies an intersection between futures studies and xenology. The measure was proposed by Soviet astronomer Nikolai Kardashev in 1964, forming the basis for a series of papers proposing ways to detect super civilizations and direct the search for extraterrestrial intelligence. Kardashev's initial model was developed starting from a functional definition of civilization, based on the immutability of physical laws, and using human civilization as a model for extrapolation. He proposed a classification of civilizations into three types, based on the axiom of exponential growth:
Carbohydrates are the main source of energy in organisms for metabolism. They are an important source of fuel in exercise. A study conducted by the Institute of Food, Nutrition, and Human Health at Massey University investigated the effect of consuming a carbohydrate and electrolyte solution on muscle glycogen use and running capacity on subjects that were on a high carbohydrate diet. The group that consumed the carbohydrate and electrolyte solution before and during exercise experienced greater endurance capacity. This could not be explained by the varying levels of muscle glycogen; however, higher plasma glucose concentration may have led to this result. Dr. Stephen Bailey posits that the central nervous system can sense the influx of carbohydrates and reduces the perceived effort of the exercise, allowing for greater endurance capacity.
Pallavi Devulapalli, health spokesperson for the Green Party of England and Wales, is suspended for calling reports of LGBTQ hate crime "mischievous" and saying she is "yet to meet anyone" who denied a person's right to "dress" and "be addressed as they please". 7 September – In a joint article published by The Financial Times, Sir Richard Moore, the chief of MI6, and William Burns, the director of the CIA, warn that the world is "under threat in a way we haven't seen since the Cold War". United Kingdom–Ireland relations: Keir Starmer travels to Ireland and meets Taoiseach Simon Harris, becoming the first British prime minister to visit Ireland for five years. He describes the occasion as a chance to reset the UK's relationship with Ireland. Former First Minister of Wales Vaughan Gething confirms he will not stand for re-election at the 2026 Senedd election. 8 September – Stephen Farry resigns as Deputy Leader of the Alliance Party, triggering a deputy leadership election. 9 September – Starmer chairs the inaugural meeting of a group dedicated to tackling knife crime, made up of police officers, figures from technology companies and the families of victims of knife crime. They are also joined by actor Idris Elba, who has campaigned against knife crime. Stormont unveils its Programme for Government, a document titled Our Plan: Doing What Matters Most, which sets out nine "immediate priorities" to be worked on for the duration of the government. A public consultation on the document is also launched.
Sources: en.wikipedia.org
Furin is a protease, a proteolytic enzyme activated by substrate presentation that in humans and other animals is encoded by the FURIN gene. Some proteins are inactive when they are first synthesized, and must have sections removed in order to become active. Furin cleaves these sections and activates the proteins. It was named furin because it was in the upstream region of an oncogene known as FES. The gene was known as FUR (FES Upstream Region) and therefore the protein was named furin. Furin is also known as PACE (Paired basic Amino acid Cleaving Enzyme). A member of family S8, furin is a subtilisin-like peptidase.
== History == The company was founded in Bremen on 24 October 1923 as Bremer Flugzeugbau AG by Prof. Henrich Focke, Georg Wulf and Dr. rer. pol. Werner Naumann. Almost immediately, they renamed the company Focke-Wulf Flugzeugbau AG (later Focke-Wulf Flugzeugbau GmbH). Focke-Wulf merged, under government pressure, with Albatros Flugzeugwerke of Berlin in 1931. The Albatros Flugzeugwerke engineer and test pilot Kurt Tank became head of the technical department and started work on the Fw 44 Stieglitz (Goldfinch). Dr Ludwig Roselius became chairman in 1925 and handed over to his brother Friedrich in early 1933. In 1938 Roselius' HAG combine increased its shareholding to 46% and C. Lorenz AG secured 28%. The company was reconstituted as Focke-Wulf Flugzeugbau GmbH and no longer had to publish its accounts. A substantial capital injection occurred at this time. In August 1933 Hans Holle and Rudolf Schubert were given power of attorney over the Berlin branch of Focke-Wulf. Then in October 1933, Focke-Wulf Flugzeugbau A.G. Albatros Berlin was officially registered with the Department of Trade. Dr Roselius always remained the driving force of Focke-Wulf. He and his closest collaborator, Barbara Goette, often met with technical director Professor Kurt Tank. When Roselius died in May 1943, Heinrich Puvogel (later chair of Focke-Wulf) raised 4 million RM and continued handling the financial affairs of Focke-Wulf as chief of Seehandel A.G. Hanna Reitsch demonstrated the Focke-Wulf Fw 61, the first fully controllable helicopter (as opposed to autogyro), in Berlin in 1938.
=== Books === Ben-Tal has also collaborated with Dr. Amit Kessel on research and teaching concerning structural biology and the origin of life. They co-authored Introduction to Proteins: Structure, Function, and Motion, first published in 2010, with a second edition published in 2018.
5 August – George Herd, 88, Scottish football player (Sunderland, national team) and manager (Queen of the South). 6 August – Ron Bain, 79, Scottish actor (Naked Video, A Kick Up the Eighties) and director (I, Lovett). (death announced on this date) Bobby Thomson, 87, Scottish footballer (Aston Villa, Birmingham City). 9 August – Brian Marjoribanks, 82, Scottish footballer (Hibernian), actor and broadcaster (BBC Scotland). 12 August – Alex Kinninmouth, 82, Scottish footballer (Dundee, Dunfermline Athletic, Forfar Athletic). (death announced on this date) 2 September – Mick Cullen, 93, Scottish footballer (Luton Town, Grimsby Town, national team). 3 September – Flora Fraser, 21st Lady Saltoun, 93, Scottish peer, member of the House of Lords (1979–2014). 6 September – Ron Yeats, 86, Scottish footballer (Dundee United, Liverpool, Tranmere Rovers). 17 September – Kenny Hyslop, 73, Scottish drummer (Slik, Zones, Simple Minds). (death announced on this date) 18 September – Sam Malcolmson, 77, Scottish-born New Zealand footballer (Queen of the South, Albion Rovers, national team). 10 October – Peter Cormack, 78, Scottish football player (Liverpool, national team) and manager (Partick Thistle). 12 October Jackmaster, 38, Scottish DJ and record producer. Alex Salmond, 69, politician, first minister (2007–2014). 13 October – Jim Liddle, 66, Scottish footballer (Forfar Athletic, Cowdenbeath, Hamilton Academical). 22 October – Jim McColl, 89, Scottish horticulturalist and television presenter (Beechgrove). Myra McFadyen, 68, Scottish actress (Made of Honor, Mamma Mia!, Emma).
Treatment options for idiopathic pulmonary fibrosis are very limited, since no current treatment has stopped the progression of the disease. Because of this, there is no evidence that any medication can significantly help this condition, despite ongoing research trials. However, current treatment options such as pirfenidone and nintedanib can help slow progression of idiopathic pulmonary fibrosis, the most common form of pulmonary fibrosis. Lung transplantation is the only therapeutic option available in severe cases. A lung transplant can improve the patient's quality of life. Immunosuppressive drugs can also be considered. These are sometimes prescribed to slow the processes that lead to fibrosis. Some types of lung fibrosis respond to corticosteroids, such as prednisone. Oxygen therapy is also an option. The patient may choose how much oxygen to use. The use of oxygen doesn't repair the lung damage, but can: make breathing and exercise easier; prevent or lessen complication from low blood oxygen levels; reduce blood pressure; and improve sleep and sense of well-being. The immune system is thought to play a central role in the development of many forms of pulmonary fibrosis. The goal of treatment with immunosuppressive agents such as corticosteroids is to decrease lung inflammation and subsequent scarring. Responses to treatment vary. Those whose conditions improve with immunosuppressive treatment probably do not have idiopathic pulmonary fibrosis, for idiopathic pulmonary fibrosis has no significant treatment or cure.
Sources: en.wikipedia.org
Selank is a seven-amino-acid peptide built from the tuftsin sequence plus a Pro-Gly-Pro tail. It is produced by chemical synthesis rather than extracted from a natural source. The free peptide is usually supplied as a lyophilised powder or in an aqueous formulation.
Tuftsin is a natural tetrapeptide derived from the Fc portion of immunoglobulin G. Selank retains that tetrapeptide at its N-terminus and adds three residues to improve resistance to enzymatic breakdown. The relationship is structural, and the two molecules are not interchangeable in experimental work.
It holds a product registration in Russia for intranasal use as an anxiolytic. Registrations of that kind are not automatically accepted by regulators elsewhere. In most other countries it is treated as an unapproved substance or a research material.
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.