This is a working overview of Selank, written for readers who want more than a one-paragraph summary but less than a textbook.
This page was last updated on 2026-08-01 and is reviewed periodically as new material appears.
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.
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.
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.
| 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 |
Proposed mechanisms centre on modulation of the GABAergic system, with reports of altered expression of genes related to GABA-A receptor subunits and changed monoamine turnover. Some studies describe inhibition of enkephalinase, the enzyme that degrades endogenous enkephalins, which may prolong opioid peptide signalling. Effects on brain-derived neurotrophic factor and on cytokine expression have also been reported. These findings come largely from animal models and small human studies, and the precise primary target remains unresolved.
Published clinical evidence is limited. Most controlled trials were conducted in Russia, enrolled modest numbers of participants, and appeared in Russian-language journals, which restricts independent verification. Reported outcomes include lower anxiety scores, improved attention and memory measures, and changes in fatigue ratings. Reviews written in English note methodological limitations such as small samples and inconsistent endpoints. Whether the compound produces clinically meaningful benefit relative to established anxiolytics is therefore an open question rather than an established finding.
Selank is a synthetic heptapeptide developed in Russia during the 1990s. Researchers at the Institute of Molecular Genetics of the Russian Academy of Sciences designed it as a stabilized analog of tuftsin, a naturally occurring immunomodulatory tetrapeptide. The compound has been studied primarily for its reported anxiolytic and nootropic effects. It remains largely unknown in Western pharmacology and is not approved as a medicine by major regulators such as the FDA or the EMA.
The primary structure of Selank is Thr-Lys-Pro-Arg-Pro-Gly-Pro, corresponding to the molecular formula C33H57N11O9 and a monoisotopic mass of roughly 751.9 daltons. The N-terminal threonine and the arginine residue in the fourth position are shared with tuftsin, which carries the sequence Thr-Lys-Pro-Arg. The three additional residues at the C-terminus, Pro-Gly-Pro, extend the chain and are associated with greater resistance to enzymatic degradation. This extension also separates Selank from the shorter parent peptide.
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.
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.
=== Symmetrical flow === Of these techniques flow FFF was the first to be offered commercially. Flow FFF separates particles based on size, independent of density and can measure macromolecules in the range of 1 nm to 1 μm. In this respect it is the most versatile FFF sub-technique available. The cross flow in Flow FFF enters through a porous frit at the top of the channel, exiting through a semi-permeable membrane outlet frit on the accumulation wall (i.e. the bottom wall). Symmetrical flow has been replaced by asymmetrical flow in the last two decades.
==== Milestones of 1,500 RBI, 1,500 runs scored and 200 stolen bases (2004) ==== When he hit his sixth career grand slam against Milwaukee on April 9, 2004, Bagwell tied a club record. He recorded his 200th career stolen base on August 30 against Cincinnati to become the tenth player in MLB history to reach that plateau while hitting 400 home runs. On September 18, 2004, Bagwell collected his 1,500th career RBI with a single in the third inning against the Brewers. Two innings later, he homered for his 1,500th run scored, becoming just the 29th player in MLB history and the first Astro to reach both milestones. Bagwell finished with 27 home runs, stopping a streak of eight consecutive seasons with at least 30, but extending a streak of 12 with at least 20. The Astros faced the Braves in the playoffs for the fourth time in Bagwell's career in the 2004 NLDS. In Game 3, on October 7, he hit his first career postseason home run off Mike Hampton in the first inning in a 4–2 extra-inning loss. After three failed attempts to advance past the first round of the playoffs earlier in Bagwell's career, losing to Atlanta in 1997, 1999, and 2001, and seven overall in 43 years of franchise history, the Astros defeated the Braves for their first-ever playoff series win. The quartet dubbed the "Killer B's," this time including Carlos Beltrán and Lance Berkman, ignited the Astros' offense, batting .395 (34-for-86) with eight home runs, 21 RBI and 24 runs scored. The Astros scored an NLDS-record 36 runs in all and Bagwell batted .318 with two home runs and five RBI.
== Research == Starting in the 1980's DeGrado's group developed the approach of de novo protein design, a term they coined to describe the design of proteins from first principles rather than through modification of natural protein sequences. They pioneered parametric approaches to the design of water-soluble 4-helix (alpha4) and 3-helix bundles (alpha3D), and ion channel peptides. The protein, alpha3D, was notable at the time, because it was the premier example of a de novo protein, which was biologically expressed, structurally validated, and whose sequence and structure were not based on the sequence or the precise tertiary structure of a natural protein. The sequence of alpha3D was designed using the computational sidechain repacking algorithms that had recently been developed by Ponders & Richards, Desjarlais & Handel, Dahiyat & Mayo. The folding kinetics of alpha3D are among the most extensively characterized of single-domain proteins, and it has been used as a template for design of metalloproteins. The company Arcellx used alpha3D as a starting point for design of chimeric antigen receptors (CARs). Clinical data announced in 2020 showed deep and durable responses of multiple myeloma, illustrating the potential of de novo proteins for treatment of human disease.
== Ultimate Fighting Championship (UFC) == In December 2013, the UFC began a campaign to drug test their entire roster randomly all year-round. Random testing, however, became problematic for the promotion as it began to affect revenue, as fighters who had tested positive would need to be taken out of fights, which adversely affected fight cards, and therefore pay-per-view sales. If the UFC were not able to find a replacement fighter fights would have to be cancelled. According to Steven Marrocco of MMAjunkie.com, about 31% of UFC fighters subjected to random testing since the program first started have failed due to using performance-enhancing drugs. That is approximately five failed tests for every sixteen random screenings. No fighters are exempt from these tests, no matter how big or small. Former Bantamweight champion T.J. Dillashaw tested positive for EPO following his fight with Henry Cejudo in January 2019. Jon Jones, the former Heavyweight and Light Heavyweight champion in the UFC, tested positive for banned substances in June 2016. Jones urine was found to contain Clomiphene and Letrozole which lead to a one-year suspension from the sport. Another highly decorated fighter by the name of Anderson Silva tested positive for two anabolic steroids following his bout against Nick Diaz at UFC 183. The steroids were methyltestosterone and Hydrochlorothiazide. From July 2015, the UFC has advocated to all commissions that every fighter be tested in competition for every card.
On Truth Social, Trump expressed his anger that the press pool had "refused to cover one of the Biggest and Most Beautiful Events to take place in many years". The press pool resumed its coverage of Trump on September 25 after the administration reinstated the news outlets.
Sources: en.wikipedia.org
Chronic infections Chemotherapeutic & Cytotoxic drugs 5-fluorouracil Hydroxyurea Hydroxycarbamide Methotrexate Following Granulocyte colony stimulating Factor (G-CSF) administration Steroid therapy for immune thrombocytopenic purpura (ITP) Iron deficiency anaemia
=== Radioactive isotopes === The existence of isotopes was first suggested in 1913 by the radiochemist Frederick Soddy, based on studies of radioactive decay chains that indicated about 40 different species referred to as radioelements (i.e. radioactive elements) between uranium and lead, although the periodic table only allowed for 11 elements between lead and uranium inclusive. Several attempts to separate these new radioelements chemically had failed. For example, Soddy had shown in 1910 that mesothorium (later shown to be 228Ra), radium (226Ra, the longest-lived isotope), and thorium X (224Ra) are impossible to separate. Attempts to place the radioelements in the periodic table led Soddy and Kazimierz Fajans independently to propose their radioactive displacement law in 1913, to the effect that alpha decay produced an element two places to the left in the periodic table, whereas beta decay emission produced an element one place to the right. Soddy recognized that emission of an alpha particle followed by two beta particles led to the formation of an element chemically identical to the initial element but with a mass four units lighter and with different radioactive properties. Soddy proposed that several types of atoms (differing in radioactive properties) could occupy the same place in the table. For example, the alpha-decay of uranium-235 forms thorium-231, whereas the beta decay of actinium-230 forms thorium-230.
The two substrates of this enzyme are β-hydroxybutyryl-CoA and oxidised nicotinamide adenine dinucleotide phosphate (NADP+). Its products are acetoacetyl-CoA, reduced NADPH, and a proton. This enzyme belongs to the family of oxidoreductases, to be specific those acting on the CH-OH group of donor with NAD+ or NADP+ as acceptor. The systematic name of this enzyme class is (S)-3-hydroxybutanoyl-CoA:NADP+ oxidoreductase. Other names in common use include beta-hydroxybutyryl coenzyme A dehydrogenase, L-(+)-3-hydroxybutyryl-CoA dehydrogenase, BHBD, dehydrogenase, L-3-hydroxybutyryl coenzyme A (nicotinamide adenine, dinucleotide phosphate), L-(+)-3-hydroxybutyryl-CoA dehydrogenase, and beta-hydroxybutyryl-CoA dehydrogenase. This enzyme participates in benzoate degradation via coa ligation and butanoate metabolism.
A study by Keyes found that there are major costs of depression, which 14% of adults experience annually: it impairs social roles; it costs billions each year due to work absenteeism, diminished productivity, and healthcare costs; finally, depression accounts for at least one-third of suicides. Therefore, it is important to study flourishing to learn about what is possible if issues such as depression are tackled and how the ramifications of focusing on the positive make life better not just for one person, but also for others around them. Flourishing has significant positive aspects magnified when compared to languishing adults and when languishing adults are compared to depressed adults, as explained by Keyes. For example, languishing adults have the same amount of chronic disease as those that are depressed whereas flourishing adults are in exceptionally better physical health. Languishing adults miss as many days at work as depressed adults and, in fact, visit doctors and therapists more than depressed adults.
Sources: en.wikipedia.org
===== Chain of any number of decays ===== For the general case of any number of consecutive decays in a decay chain, i.e. A1 → A2 ··· → Ai ··· → AD, where D is the number of decays and i is a dummy index (i = 1, 2, 3, ..., D), each nuclide population can be found in terms of the previous population. In this case N2 = 0, N3 = 0, ..., ND = 0. Using the above result in a recursive form:
=== Thailand === Thailand has been severely impacted by the crisis. Thailand imports 57% of its oil from the Middle East, which requires to pass the Strait of Hormuz. The diesel fuel price has increased from 29.94 THB per litre in February, up to peak price of 50.54 THB per litre in 7 April. The government froze diesel prices at 29.94 THB per litre in the first 15 days of the crisis, and has directed people to raise their air-conditioning temperatures and reduce their outer clothing, to reduce energy consumption, and employees of all government agencies are working from home. Phipat Ratchakitprakarn, Deputy Prime Minister of Thailand and co-owner of PTG Energy (branded as PT), one of the largest oil companies in Thailand, was assigned by Anutin Charnvirakul, Prime Minister of Thailand to control and mitigate the impact of fuel crisis in Thailand. He has been criticised by Thai citizens for his failure to manage the impact, and the "Ban PT" movement has gained traction across the internet. In Pathum Thani Province, north of Bangkok, the local Provincial Administrative Organization (PAO) has terminated its 4.45 satang per litre (Equivalent to 0.445 THB) fuel dispenser tax for 3 months, in 317 stations across the province. Normally, this tax generates 4 million THB per month for the PAO. By this measure the PAO hopes to reduce fuel costs for the residents of Pathum Thani Province, especially for farmers.
Theodoros "Theo" Angelopoulos (Greek: Θεόδωρος Αγγελόπουλος; 27 April 1935 – 24 January 2012) was a Greek filmmaker, screenwriter and film producer. He dominated the Greek art film industry from 1975 on, and Angelopoulos was one of the most influential and widely respected filmmakers in the world. He started making films in 1967. In the 1970s he made a series of political films about modern Greece. Angelopoulos' films, described by Martin Scorsese as those of "a masterful filmmaker", are characterized by slight movement and distance changes, long takes, and complex, carefully composed scenes. His cinematic method is often described as "sweeping" and "hypnotic." Angelopoulos has said that in his shots, “time becomes space and space becomes time.” The pauses between action or music are important to creating the total effect. In 1998 his film Eternity and a Day went on to win the Palme d'Or at the 51st edition of the Cannes Film Festival, and his films have been shown at many of the world's esteemed film festivals.
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.
Identity is confirmed by matching the retention time in reversed-phase chromatography against a reference standard and by measuring the molecular mass with mass spectrometry. Tandem mass spectrometry or amino acid analysis can verify the sequence of the seven residues. Because the peptide contains no aromatic amino acids, detection at 280 nm is not useful.