Semax raises a handful of sensible questions. This page answers them in order, starting with the fundamentals and moving to applications.
This page was last updated on 2026-07-29 and is reviewed periodically as new material appears.
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.
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.
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.
| Property | Value | Notes |
|---|---|---|
| Dry storage temperature | -20 C or below | Sealed, desiccated, protected from light |
| Solution stability | Hours to days at 2-8 C | Depends on buffer and microbial load |
| Preferred pH range | Near neutral to slightly acidic | Alkaline pH accelerates hydrolysis |
| Main degradation routes | Hydrolysis and deamidation | No cysteine or methionine in sequence |
| Identity confirmation | Electrospray mass spectrometry | Observed mass compared with 751.9 Da |
Measuring peptide exposure inside the brain is technically difficult. Selank is degraded rapidly in plasma, and assays must separate intact peptide from fragments, which favors targeted mass spectrometry over immunoassays alone. Reported half-lives are short, on the order of minutes, so effects observed hours later are attributed to downstream signaling rather than to the parent compound. Blood-brain barrier permeability is debated and rarely quantified directly. Gaps include absent dose-response characterization, inconsistent reporting of purity, and almost no pharmacokinetic data from human participants.
Selank is studied chiefly as an animal-model anxiolytic with proposed secondary effects on memory and immune signaling. Reported mechanisms include modulation of the GABA-A receptor complex, inhibition of enkephalin-degrading enzymes, and shifts in monoamine turnover within limbic structures. Some experiments describe increased expression of brain-derived neurotrophic factor in the hippocampus after repeated dosing. No single molecular target has been confirmed, and the peptide does not bind any receptor with the selectivity typical of a conventional small-molecule drug. Mechanism therefore remains a set of hypotheses rather than an established pathway.
Laboratory work relies on standard behavioral paradigms. Rodents are tested in the elevated plus maze, open field, and passive avoidance tasks, with outcomes compared against diazepam or vehicle controls. Intranasal dosing is used most often because it bypasses first-pass metabolism, though intraperitoneal and intravenous routes also appear in published protocols. Biochemical endpoints include tissue BDNF concentrations, cytokine levels, and monoamine metabolites. Human data are limited to small Russian trials reporting reduced anxiety scores; most were not prospectively registered, and few employed independent outcome assessment.
Development work on the compound began in the 1980s and 1990s at the Institute of Molecular Genetics in Moscow, within the same research programme that produced the peptide Semax. Early investigators sought a tuftsin derivative with improved resistance to enzymatic breakdown and with activity in the central nervous system after peripheral administration. Most of the primary literature from this period was published in Russian, a factor that still shapes how easily the findings can be checked by outside groups.
Naming for this compound is not fully standardised in English sources. The spelling Selanc appears in some transliterations, and catalogue entries may instead list the peptide sequence itself as the identifier. Reference material sometimes groups it with other short synthetic peptides studied for behavioural effects, which can create confusion when citations are compared. Distinguishing the exact sequence from related tuftsin analogues is therefore a practical first step when reviewing any dataset or specification sheet.
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.
In historical fungarium material, contamination can be especially severe because specimens were often stored in close contact on paper sheets or in herbarium packets, increasing the likelihood of cross-contamination, while universal fungal barcode primers may amplify contaminant fungi alongside the target specimen. High-throughput sequencing is better suited to such degraded material. In 2012, researchers reported successful ITS sequencing from a lichen herbarium specimen collected in 1859, then the oldest sequenced fungal herbarium sample. A 2025 study showed that historical lichen specimens, including type material, could be used for whole genome sequencing, allowing genome-wide analysis of both the fungal and algal symbionts. High-throughput sequencing can also recover barcode data from very small amounts of historical material, reducing the need for destructive sampling of valuable specimens while allowing taxonomic re-evaluation of long-preserved collections. A modified metabarcoding approach using nested, barcoded primers has enabled the cost-effective sequencing of hundreds of specimens simultaneously. In one study, this approach produced ITS sequences for 762 out of 766 macrofungal specimens, with taxonomic identities derived from the sequence data achieving over 90 percent accuracy. Such methods have allowed previously unidentified or misidentified specimens to be recognized under newer taxonomic concepts.
Since 1971, SI defined the "amount of substance" as a separate dimension of measurement. Until 2019, the mole was defined as the amount of substance that has as many constituent particles as there are atoms in 12 grams of carbon-12, with the dalton defined as +1/12 of the mass of a carbon-12 atom. Thus, during that period, the numerical value of the molar mass of a substance expressed in g/mol was exactly equal to the numerical value of the average mass of an entity (atom, molecule, formula unit) of the substance expressed in daltons. Since 2019, the mole has been redefined in the SI as the amount of any substance containing exactly 6.02214076×1023 entities, fixing the numerical value of the Avogadro constant NA when expressed in the unit mol−1, but because the dalton is still defined in terms of the experimentally determined mass of a carbon-12 atom, the numerical equivalence between the molar mass of a substance and the average mass of an entity of the substance is now only approximate, but equality may still be assumed with high accuracy—(the relative discrepancy is only of order 10–9, i.e. within a part per billion).
=== Charles Hanani === Charles Hanani (Adam Levy) is Yasmin's father, and the wealthy CEO of the Hanani Publishing company. Charles is a serial philanderer, long divorced from Yasmin's mother Azar. He has a strained relationship with Yasmin, whom he treats like a child, and who carries trauma from growing up around her father's sexually inappropriate behavior. Charles reenters Yasmin’s life in series 2 when he arrives in London on business. Hoping to transition into Pierpoint’s private wealth management division, Yasmin brings him on as a client, only to learn that much of his fortune has been drained by nondisclosure settlements with women he had affairs with—including her former nanny, leading Yasmin to realize he likely groomed her. When confronted, Charles attacks Yasmin for condemning him while benefiting from his wealth and cuts her off financially. In series 3, Yasmin joins Charles on his yacht in Mallorca and catches him performing oral sex on a pregnant employee. Amid revelations that he is being sued by his own company for historic embezzlement, the two engage in a vicious confrontation in which Yasmin accuses him of sexualizing her throughout her life. A drunken Charles jumps overboard after Yasmin wishes him dead, and she makes no attempt to save him; Harper helps cover up her involvement. After Charles’ body is recovered, Hanani Publishing scapegoats Yasmin to deflect from its own complicity in silencing his victims, prompting her to sue the company.
Phthalates have been banned from use in feeding bottles in the EU. In the US, there have been repeated calls for the removal of phthalates by the U.S. Consumer Product Safety Commission (CPSC) and others. Their use in children's toys and products was somewhat restricted by the Consumer Product Safety Improvement Act of 2008. Plastics labeled #3 may leach phthalates. Latex rubber nipples may contain phthalates, so silicone nipples may be recommended instead. Packaging may indicate whether a product is "BPA-free" or "phthalate-free". Plastics may degrade over time in other ways, There are concerns that small beads of plastic may be released into fluids from some types of plastic bottles. In 2020 researchers reported that infant feeding bottles made out of polypropylene caused microplastics exposure to infants ranging from 14,600 to 4,550,000 particles per capita per day in 48 regions with contemporary preparation procedures. Microplastics release is higher with warmer liquids and similar with other polypropylene products such as lunchboxes. In 2022, the first study to examine the presence of plastic polymers in human blood found plastics of multiple types in the blood samples of 17 out of 22 healthy adults tested (nearly 80%). Medical experts have suggested reducing exposure to microplastics by not shaking plastic bottles or exposing them to high temperatures. Some recommend using alternative materials such as glass, silicone, or stainless steel.
Sources: en.wikipedia.org
=== Birth rate === According to one report, in 1924, shortly after the Free State's establishment, the new dominion had the "lowest birth-rate in the world". The report noted that amongst countries for which statistics were available (Ceylon, Chile, Japan, Spain, South Africa, the Netherlands, Canada, Germany, Australia, the United States, Britain, New Zealand, Finland, and the Irish Free State), Ceylon had the highest birth rate at 40.8 per 1,000 while the Irish Free State had a birth rate of just 18.6 per 1,000.
== In other organisms == Many bacteria synthesize menaquinones from chorismic acid. They use it as a part of the electron transport chain, playing a similar role as other quinones such as ubiquinone. Oxygen, heme, and menaquinones are needed for many species of lactic acid bacteria to conduct respiration. Variations in biosynthetic pathways mean that bacteria also produce analogues of vitamin K2. For example, MK9(II-H), which replaces the second geranylgeranyl unit with a saturated phytyl, is produced by Mycobacterium phlei. There also exists a possibility of cis–trans isomerism due to the double bonds present. In M. phlei, the 3'-methyl-cis MK9(II-H) form seems to be more biologically active than trans MK9(II-H). However, with human enzymes, the naturally abundant trans form is more efficient. One hydrogenated MK that sees relevant amounts of human consumption is MK-9(4H), found in cheese fermented by Propionibacterium freudenreichii. This variation has the second and third units replaced with phytyl.
N-Terminal domain antiandrogens are a novel type of antiandrogen that bind to the N-terminal domain of the androgen receptor (AR) instead of the ligand-binding domain (where all currently-available antiandrogens bind) and disrupt interactions between the AR and its coregulatory binding partners, thereby blocking AR-mediated gene transcription. They are being investigated for the treatment of prostate cancer.
Aagenaes syndrome Acroangiodermatitis (acroangiodermatitis of Mali, Mali acroangiodermatitis, Pseudo-Kaposi's sarcoma) Acrocyanosis Acute hemorrhagic edema of infancy (acute hemorrhagic edema of childhood, Finkelstein's disease, infantile postinfectious iris-like purpura and edema, medallion-like purpura, purpura en cocarde avec oedema, Seidlmayer syndrome) Arterial insufficiency ulcer (ischemic ulcer) Arteriosclerosis obliterans Bier spots Blueberry muffin baby Bonnet–Dechaume–Blanc syndrome (Wyburn–Mason syndrome) Bullous lymphedema Bullous small vessel vasculitis (bullous variant of small vessel vasculitis) Calciphylaxis Caput succedaneum Cholesterol embolus (warfarin blue toe syndrome) Cobb syndrome Corona phlebectatica Cryofibrinogenemic purpura Cryoglobulinemic purpura Cryoglobulinemic vasculitis Cutaneous small-vessel vasculitis (cutaneous leukocytoclastic angiitis, cutaneous leukocytoclastic vasculitis, cutaneous necrotizing venulitis, hypersensitivity angiitis) Deep venous thrombosis Disseminated intravascular coagulation Doucas and Kapetanakis pigmented purpura Drug-induced purpura Drug-induced thrombocytopenic purpura Eczematid-like purpura of Doucas and Kapetanakis Epidemic dropsy Erythema elevatum diutinum Erythromelalgia (acromelalgia, erythermalgia) Factitial lymphedema (hysterical edema) Fibrinolysis syndrome (defibrinating syndrome, hypofibrinogenemia) Food-induced purpura Generalized essential telangiectasia (general essential telangiectasia) Giant-cell arteritis Gougerot–Blum syndrome (pigmented purpuric lichenoid dermatitis, pigmented purpuric lichenoid dermatitis of Gougerot and Blum) Granulomatosis with polyangiitis Harlequin color change Hematopoietic ulcer Hennekam syndrome (Hennekam lymphangiectasia-lymphedema syndrome, intestinal lymphagiectasia-lymphedema-mental retardation syndrome) Henoch–Schönlein purpura (anaphylactoid purpura, purpura rheumatica, Schönlein–Henoch purpura) Hereditary hemorrhagic telangiectasia (Osler's disease, Osler–Weber–Rendu disease) Idiopathic thrombocytopenic purpura (autoimmune thrombocytopenic purpura, Werlhof's disease) IgA vasculitis Kawasaki's disease (mucocutaneous lymph node syndrome) Levamisole-induced vasculitis Lichen aureus (lichen purpuricus) Livedo racemosa Livedo reticularis Livedoid dermatitis (embolia cutis medicamentosa, Nicolau syndrome) Livedoid vasculopathy (atrophie blanche, livedo reticularis with summer ulceration, livedoid vasculitis, PURPLE syndrome, segmental hyalinizing vasculitis) Lymphedema praecox Lymphedema–distichiasis syndrome Maffucci syndrome Majocchi's disease (purpura annularis telangiectodes, purpura annularis telangiectodes of Majocchi) Malignant atrophic papulosis (Degos' disease) Marshall–White syndrome Meige lymphedema Microscopic polyangiitis (microscopic polyarteritis, microscopic polyarteritis nodosa) Mondor's disease (Mondor's syndrome of superficial thrombophlebitis) Neuropathic ulcer (mal perforans) Njolstad syndrome Nonne–Milroy–Meige syndrome (hereditary lymphedema, Milroy disease) Obstructive purpura Orthostatic purpura (stasis purpura) Painful bruising syndrome (autoerythrocyte sensitization, Gardner–Diamond syndrome, psychogenic purpura) Parkes Weber syndrome Paroxysmal hand hematoma (Achenbach syndrome) Paroxysmal nocturnal hemoglobinuria Polyarteritis nodosa (panarteritis nodosa, periarteritis nodosa) Postcardiotomy syndrome Perinatal gangrene of the buttock Pigmentary purpuric eruptions (progressive pigmentary dermatosis, progressive pigmenting purpura, purpura pigmentosa chronica) Postinflammatory lymphedema Postmastectomy lymphangiosarcoma (Stewart–Treves syndrome) Purpura fulminans (purpura gangrenosa) Purpura secondary to clotting disorders Purpuric agave dermatitis Raynaud phenomenon Raynaud's disease (primary Raynaud's phenomenon) Reactive angioendotheliomatosis Schamberg's disease (progressive pigmentary dermatosis of Schamberg, purpura pigmentosa progressiva, Schamberg's purpura) Secondary lymphedema Septic thrombophlebitis Sinusoidal hemangioma Sneddon's syndrome (idiopathic livedo reticularis with cerebrovascular accidents) Solar purpura (actinic purpura, senile purpura) Stasis dermatitis (congestion eczema, gravitational dermatitis, gravitational eczema, stasis eczema, varicose eczema) Superficial thrombophlebitis Takayasu arteritis (aortic arch syndrome, pulseless disease) Temporal arteritis (cranial arteritis, Horton's disease) Thromboangiitis obliterans (Buerger's disease) Thrombotic thrombocytopenic purpura (Moschcowitz syndrome) Traumatic purpura Trousseau's syndrome Unilateral nevoid telangiectasia (nevoid telangiectasia) Urticarial vasculitis (chronic urticaria as a manifestation of venulitis, hypocomplementemic urticarial vasculitis syndrome, hypocomplementemic vasculitis, unusual lupus-like syndrome) Venous insufficiency ulceration Waldenström hyperglobulinemic purpura (purpura hyperglobulinemica) Waldenström macroglobulinemia Yellow nail syndrome (primary lymphedema associated with yellow nails and pleural effusion)
=== Other types === Other types of chocolate are used in baking and confectionery. These include baking chocolate (often unsweetened), couverture chocolate (used for coating), compound chocolate (a lower-cost alternative) and modeling chocolate. Modeling chocolate is a chocolate paste made by melting chocolate and combining it with corn syrup, glucose syrup, or golden syrup.
Sources: en.wikipedia.org
acute viral infections, such as infectious mononucleosis (glandular fever), hepatitis and cytomegalovirus infection other acute infections such as pertussis some protozoal infections, such as toxoplasmosis and American trypanosomiasis (Chagas disease) chronic intracellular bacterial infections such as tuberculosis or brucellosis chronic lymphocytic leukemia acute lymphoblastic leukemia lymphoma post-splenectomy state CARD11-related congenital B cell lymphocytosis (rare, also known as BENTA disease) Causes of relative lymphocytosis include:
=== Transseptal fibers === Transseptal fibers (H) extend interproximally over the alveolar bone crest and are embedded in the cementum of adjacent teeth; they form an interdental ligament. These fibers keep all the teeth aligned. These fibers may be considered as belonging to the gingival tissue because they do not have an osseous attachment. These fibers are consistent and are reconstructed even after the destruction of alveolar bone.
If {H3O+} increases {CH3CO2H} must increase and CH3CO−2 must decrease. The H2O is left out, as it is the solvent and its concentration remains high and nearly constant. J. W. Gibbs suggested in 1873 that equilibrium is attained when the "available energy" (now known as Gibbs free energy or Gibbs energy) of the system is at its minimum value, assuming the reaction is carried out at a constant temperature and pressure. What this means is that the derivative of the Gibbs energy with respect to reaction coordinate (a measure of the extent of reaction that has occurred, ranging from zero for all reactants to a maximum for all products) vanishes (because dG = 0), signaling a stationary point. This derivative is called the reaction Gibbs energy (or energy change) and corresponds to the difference between the chemical potentials of reactants and products at the composition of the reaction mixture. This criterion is both necessary and sufficient. If a mixture is not at equilibrium, the liberation of the excess Gibbs energy (or Helmholtz energy at constant volume reactions) is the "driving force" for the composition of the mixture to change until equilibrium is reached. The equilibrium constant can be related to the standard Gibbs free energy change for the reaction by the equation
8 July An infantry battalion numbering 814 men from the US Army's 9th Infantry Division, the first of 25,000 American troops to be withdrawn from South Vietnam, arrived at McChord Air Force Base at 18:30 in a C-141 transport plane.
Sources: en.wikipedia.org
Dry powder is best kept sealed, protected from light, and held at minus 20 degrees Celsius or below. Desiccant packaging helps limit moisture uptake because the material is hygroscopic. A sealed vial should be allowed to equilibrate to room temperature before opening to reduce condensation.
Hydrolysis of peptide bonds and deamidation of arginine and proline residues are the main degradation routes. Alkaline pH and higher temperatures accelerate both processes. Buffered, near-neutral solutions stored cold generally degrade more slowly than unbuffered ones.
Reverse-phase chromatography gives the clearest single view of related impurities and truncated sequences. Mass spectrometry then confirms that the main peak carries the expected mass. Neither test detects enantiomeric impurities, which require a separate chiral assay.
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.