A practical reference on Certificate of analysis: what it is, how it behaves, what the literature reports, and where the honest uncertainties sit.
Reviewed 2025-10-18. Anything still debated is marked as such rather than presented as settled.
Selank is a synthetic heptapeptide with the sequence Thr-Lys-Pro-Arg-Pro-Gly-Pro. It was designed at the Institute of Molecular Genetics of the Russian Academy of Sciences as a structural analogue of tuftsin, a naturally occurring tetrapeptide fragment of the immunoglobulin heavy chain. The added Pro-Gly-Pro tail was intended to slow enzymatic degradation and extend biological activity. In Russia it is registered as an anxiolytic nasal preparation, while regulators elsewhere have not approved it for clinical use.
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.
Once dissolved, the peptide is markedly less stable than the dry powder. Aqueous solutions are subject to backbone hydrolysis and to microbial growth when they are handled without sterile technique. Buffered solutions near neutral pH are common for short-term laboratory work, while acidic conditions are sometimes used to improve solubility. Analytical laboratories generally prepare working solutions fresh rather than storing them, and a residual water film left in a reopened vial can seed degradation even when the container appears dry.
Reversed-phase high-performance liquid chromatography is the standard technique for estimating peptide purity. The result is a peak-area percentage, which describes how much of the detected material elutes as the main peak in one run. Mass spectrometry confirms the molecular mass and can reveal truncated, adducted, or otherwise modified species. Amino acid analysis or tandem mass spectrometry can address sequence fidelity when identity is in doubt. None of these measurements, taken alone, establishes that a sample is fit for any specific purpose.
Lyophilized selank is normally supplied as a dry powder and is considered stable for extended periods when kept cold and dry. Moisture uptake is the main practical threat, because absorbed water promotes both hydrolysis and aggregation in the solid state. Vials are usually warmed to room temperature before opening so that condensation does not form on the powder. Supplier documentation commonly specifies -20 °C for routine storage, with -80 °C used for material intended to be archived for years.
| Property | Value | Notes |
|---|---|---|
| Molecular formula | C33H57N11O9 | Free peptide form |
| Molecular mass | About 751.9 Da | Calculated average mass |
| Amino acid sequence | Thr-Lys-Pro-Arg-Pro-Gly-Pro | Single-letter form TKPRPGP |
| Structural basis | Tuftsin analogue | Extended version of a natural tetrapeptide |
| Development origin | Russian Academy of Sciences | Work carried out from the 1980s onward |
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.
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.
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.
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.
Naming conventions place Selank in the same research family as Semax, another Russian-developed peptide investigated for cognitive effects. The two compounds share a lineage but differ in sequence and in the biological systems proposed as their targets. Semax descends from ACTH fragments, whereas Selank descends from tuftsin. Publications sometimes identify Selank by its full peptide sequence or by laboratory codes rather than one uniform trade name. Because replication outside Russia is limited, reports on its properties are best read alongside the study design and the purity of the material tested.
=== Reconstituted Fearsome Foursome and rejecting name === After missing the playoffs from 1970 to 1972, the Rams won seven straight division titles from 1973 to 1979, which was an NFL record until 2016 when broken by the New England Patriots. Those Rams teams were led in part by a reconstituted "new" Fearsome Foursome. This line consisted of ends Jack Youngblood and Fred Dryer, and tackles Olsen and Larry Brooks. Youngblood played for the Rams from 1971 to 1984, Brooks from 1972 to 1982, and Dryer from 1972 to 1981. Olsen, who played with his brother Phil Olsen for 4 seasons from 1971 to 1974, retired after a 15-year career at the end of the 1976 season. Olsen was replaced by Cody Jones in 1977-78. Jones suffered an Achilles tendon injury and missed the 1979 season, being replaced by Mike Fanning in 1979. Jones was the starter at right defensive tackle again in 1980. Brooks, Youngblood and Dryer, however, rejected the name Fearsome Foursome as applied to themselves, considering it unnecessary. Youngblood thought it amounted to gratuitous showmanship and the Rams' defensive players believed the team's play, not its name, was the only thing that had actual meaning. Thus, the defensively excellent 1978 team, which gave up the league’s fewest total yards and fewest passing yards, was not even considered to have a nickname, unlike the "Doomsday Defense" or "Steel Curtain". Youngblood, Dryer, Brooks and Fanning started in Super Bowl XIV following the 1979 season. Youngblood and Olsen are NFL Hall of Famers while Brooks made the Pro Bowl 5 times.
==== Trilayer ==== An electric field can change trilayer graphene's crystal structure, transforming its behavior from metal-like into semiconductor-like. A sharp metal scanning tunneling microscopy tip was able to move the domain border between the upper and lower graphene configurations. One side of the material behaves as a metal, while the other side behaves as a semiconductor. Trilayer graphene can be stacked in either Bernal or rhombohedral configurations, which can exist in a single flake. The two domains are separated by a precise boundary at which the middle layer is strained to accommodate the transition from one stacking pattern to the other. Silicon transistors are either p-type or n-type, whereas graphene can operate as both. This lowers costs and is more versatile. The technique provides the basis for a field-effect transistor. In trilayer graphene, the two stacking configurations exhibit different electronic properties. The region between them consists of a localized strain soliton where the carbon atoms of one graphene layer shift by the carbon–carbon bond distance. The free-energy difference between the two stacking configurations scales quadratically with electric field, favoring rhombohedral stacking as the electric field increases. This ability to control the stacking order opens the way to new devices that combine structural and electrical properties.
==== Essays on fascism ==== Starting with his 1947 essay Wagner, Nietzsche and Hitler, Adorno produced a series of influential works to describe psychological fascist traits. One of these works was The Authoritarian Personality (1950), published as a contribution to the Studies in Prejudice performed by multiple research institutes in the US, and consisting of 'qualitative interpretations' that uncovered the authoritarian character of test persons through indirect questions. The books have had a major influence on sociology and remain highly discussed and debated. In 1951 he continued on the topic with his essay Freudian Theory and the Pattern of Fascist Propaganda, in which he said that "Psychological dispositions do not actually cause fascism; rather, fascism defines a psychological area which can be successfully exploited by the forces which promote it for entirely non-psychological reasons of self-interest." In 1952 Adorno participated in a group experiment, revealing residual National Socialist attitudes among the recently democratized Germans. He then published two influential essays, The Meaning of Working Through the Past (1959) and Education after Auschwitz (1966), in which he argued on the survival of the uneradicated National Socialism in the mindsets and institutions of the post-1945 Germany and that there is still a real risk that it could rise again.
Glutathione disulfide (GSSG) is a disulfide derived from two glutathione molecules. In living cells, glutathione disulfide is reduced into two molecules of glutathione with reducing equivalents from the coenzyme NADPH. This reaction is catalyzed by the enzyme glutathione reductase. Antioxidant enzymes, such as glutathione peroxidases and peroxiredoxins, generate glutathione disulfide during the reduction of peroxides such as hydrogen peroxide (H2O2) and organic hydroperoxides (ROOH):
Sources: en.wikipedia.org
==== Crosstalk ==== Many known phosphorylation sites and O-GlcNAcylation sites are nearby each other or overlapping. As protein O-GlcNAcylation and phosphorylation both occur on serine and threonine residues, these post-translational modifications can regulate each other. For example, in CKIIα, S347 O-GlcNAc has been shown to antagonize T344 phosphorylation. Reciprocal inhibition, i.e., phosphorylation inhibition of O-GlcNAcylation and O-GlcNAcylation of phosphorylation, has been observed on other proteins including murine estrogen receptor β, RNA Pol II, tau, p53, CaMKIV, p65, β-catenin, and α-synuclein. Positive cooperativity has also been observed between these two post-translational modifications, i.e., phosphorylation induces O-GlcNAcylation or O-GlcNAcylation induces phosphorylation. This has been demonstrated on MeCP2 and HDAC1. In other proteins, e.g., cofilin, phosphorylation and O-GlcNAcylation appear to occur independently of each other. In some cases, therapeutic strategies are under investigation to modulate O-GlcNAcylation to have a downstream effect on phosphorylation. For instance, elevating tau O-GlcNAcylation may offer therapeutic benefit by inhibiting pathological tau hyperphosphorylation. Besides phosphorylation, O-GlcNAc has been found to influence other post-translational modifications such as lysine acetylation and monoubiquitination.
CYP1A2 (strongly) which metabolizes agomelatine, amitriptyline, caffeine, clomipramine, clozapine, duloxetine, haloperidol, imipramine, phenacetin, tacrine, tamoxifen, theophylline, olanzapine, etc. CYP3A4 (moderately) which metabolizes alprazolam, aripiprazole, clozapine, haloperidol, quetiapine, pimozide, ziprasidone, etc. CYP2D6 (weakly) which metabolizes aripiprazole, chlorpromazine, clozapine, codeine, fluoxetine, haloperidol, olanzapine, oxycodone, paroxetine, perphenazine, pethidine, risperidone, sertraline, thioridazine, zuclopenthixol, etc. CYP2C9 (moderately) which metabolizes nonsteroidal anti-inflammatory drugs, phenytoin, sulfonylureas, etc. CYP2C19 (strongly) which metabolizes clonazepam, diazepam, phenytoin, etc. CYP2B6 (weakly) which metabolizes bupropion, cyclophosphamide, sertraline, tamoxifen, valproate, etc. By so doing, fluvoxamine can increase serum concentration of the substrates of these enzymes. Fluvoxamine may also elevate plasma levels of olanzapine by approximately two times. Combined olanzapine and fluvoxamine, which may cause increased sedation, should be used cautiously and controlled clinically and by therapeutic drug monitoring to avoid olanzapine induced adverse effects and/or intoxication. The plasma levels of oxidatively metabolized benzodiazepines (e.g., triazolam, midazolam, alprazolam, and diazepam) are likely to be increased when co-administered with fluvoxamine.
Two mechanisms of resistance to temozolomide effects have now been described: 1) intrinsic resistance conferred by MGMT deficiency (MGMTd) and 2) intrinsic or acquired resistance through MMR deficiency (MMRd). The MGMT enzyme is the first line of repair of mismatched bases created by temozolomide. Cells are normally MGMT proficient (MGMTp) as they have an unmethylated MGMT promoter allowing the gene to be expressed normally. In this state, temozolomide induced DNA damage is able to be efficiently repaired in tumor cells (and normal cells) by the active MGMT enzyme. Cells may grow and pass through the cell cycle normally without arrest or death. However, some tumors cells are MGMT deficient (MGMTd). This is most commonly due to abnormal methylation of the MGMT gene promoter and suppression of gene expression. MGMTd has also been described to occur by promoter rearrangement. In cells with MGMTd, DNA damage by temozolomide activates the next stage of repair in cells with a proficient mismatch repair enzyme complex (MMRp). In MMRp the MMR protein complex identifies the damage and causes cells to arrest and undergo death which inhibits tumor growth. However, if cells have combined MGMTd and MMR deficiency (MGMTd + MMRd) then cells retain the induced mutations and continue to cycle and are resistant to effects of temozolomide. In gliomas and other cancers MMRd has now been reported to occur as primary MMRd (intrinsic or germline Lynch bMMRd) or as secondary MMRd (acquired - not present in the original untreated tumor).
A British Chamber of Commerce survey found that 95% of SMEs using generic AI tools reported no impact on headcount over the previous 12 months. However, among the minority of firms adopting bespoke AI systems, 21% reported a decrease in headcount, suggesting that deeper AI integration leads to organisational restructuring.
1990 Thomas Jefferson Award from the University of Virginia Distinguished Alumni Award from the University of Minnesota Medical Alumni Association (2005) James D. Mills Award from the American College of Emergency Physicians (2008) Solomon A. Berson Award in Health Sciences from the New York University School of Medicine (2011).
Sources: en.wikipedia.org
=== Usage of temporary foreign workers === Following the COVID-19 pandemic, Tim Hortons utilized the temporary foreign worker program (TFW) to fill employee vacancies. In December 2025, CBC News reported that the company had lobbied federal politicians to expand the program. In May 2026, Tim Hortons announced that it would seek to "hire local" and reduce its usage of the program, stating that 4,000 of its employees were hired through the TFW program as of 2026.
==== Myanmar earthquake, March 2025 ==== President Trump stated the United States would help in response to the March 28 earthquake in Myanmar, although the question was asked by a former USAID executive of whether or not the United States will beat other countries in getting there with a relief team(s).
== Cause == A seroma is usually caused by surgery. Seromas are particularly common after breast surgery (e.g., mastectomy), abdominal surgery, and reconstructive surgery. It can also be seen after neck surgery, thyroid and parathyroid surgery, and hernia repair. The larger the surgical intervention, the more likely that seromas form. Early or improper removal of sutures can sometimes lead to formation of seroma or discharge of serous fluid from operative areas. Seromas can also sometimes be caused by injury, such as when the initial swelling from a blow or fall does not fully subside. The remaining serous fluid causes a seroma that the body usually absorbs gradually over time (often taking many days or weeks), but a knot of calcified tissue sometimes remains. Large seromas take longer to resolve than small ones, and they are more likely to undergo secondary infection. A seroma may persist for several months, or even years as the surrounding tissue hardens. Seroma is the most common surgical complication after breast surgery. It is due to the presence of rich lymphatic system in the breast, low fibrinogen levels in lymph fluid and potential space creation in the breast after surgery, which contributes to seroma formation. Seroma is more common in older and obese people.
=== Metabolism === Ribose is referred to as the "molecular currency" because of its involvement in intracellular energy transfers. For example, nicotinamide adenine dinucleotide (NAD), flavin adenine dinucleotide (FAD), and nicotinamide adenine dinucleotide phosphate (NADP) all contain the d-ribofuranose moiety. They can each be derived from d-ribose after it is converted to d-ribose 5-phosphate by the enzyme ribokinase. NAD, FAD, and NADP act as electron acceptors in biochemical redox reactions in major metabolic pathways including glycolysis, the citric acid cycle, fermentation, and the electron transport chain.
Sources: en.wikipedia.org
It is a seven-amino-acid peptide, Thr-Lys-Pro-Arg-Pro-Gly-Pro, produced by chemical synthesis rather than extracted from biological tissue. Its design is based on tuftsin, a natural immunomodulatory tetrapeptide. The C-terminal Pro-Gly-Pro segment is a common stabilising motif in short regulatory peptides.
The core four residues correspond to tuftsin, which occurs naturally as part of immunoglobulin G. The full seven-residue sequence, however, is not a known endogenous peptide. It is a laboratory-designed analogue intended to combine tuftsin-like activity with greater resistance to breakdown.
No single receptor has been confirmed as the primary target. Reports describe involvement of the GABAergic system, interference with enkephalin degradation, and shifts in neurotrophic factor expression. Because these observations come from different models and assays, they have not yet been integrated into one accepted mechanism.
Sealed, desiccated storage at -20 °C or colder is the standard recommendation for research-grade material. Vials should reach room temperature before they are opened, which limits condensation. Repeated temperature cycling is discouraged.