If you have been reading about freeze-thaw and want a single page that covers the useful parts, this is it: definitions, context, how it is studied, and the questions that come up repeatedly.
Last reviewed on 2026-07-14. Where a claim depends on a specific study, the study is described rather than over-claimed.
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.
Outside its country of origin the compound is generally handled as a research chemical rather than an approved medicine. No regulatory approval from the United States Food and Drug Administration or the European Medicines Agency has been granted for human use. Identity and purity are normally checked by reverse-phase high-performance liquid chromatography, with mass spectrometry used to confirm the molecular mass. Lyophilised material is stored cold and desiccated, and repeated freeze-thaw cycles are avoided.
Published work on this peptide almost always uses intranasal delivery, with drops or a spray applied to the nasal mucosa. Some animal experiments have used subcutaneous or intraperitoneal injection, and a smaller number have compared routes directly. Oral administration is not a focus of the literature, because short peptides of this size are broken down by digestive enzymes and cross intestinal barriers poorly. How much of an intranasal dose reaches the bloodstream intact in humans remains an open question.
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.
| Property | Value | Notes |
|---|---|---|
| Appearance | White to off-white powder | Lyophilised solid form |
| Solubility class | Freely soluble in water | Hydrophilic heptapeptide |
| Dry storage temperature | -20 degrees Celsius or lower | Sealed, desiccated, protected from light |
| Solution storage | 2 to 8 degrees Celsius short term | Avoid repeated freeze-thaw cycles |
| Common identification method | Reversed-phase HPLC with mass spectrometry | Confirms purity and molecular mass |
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.
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 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.
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.
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.
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.
Promising results of health and medical research are reported: non-human vaccinated primates-tested pGal–antigen therapy for suppressing antigen-specific immune responses and against autoimmune diseases, this type of vaccine is called "inverse vaccine" (7 Sep), 3D cell-culture tested exercise-induced hormone irisin against Aβ Alzheimer's disease pathology (8 Sep), identified diverse features strongly associated with long COVID for better diagnosis (25 Sep). Promising innovations relating to global challenges are reported: a study winning an international competition demonstrates an approach that predicted 70% of earthquakes, suggesting some form of earthquake prediction may be feasible in the future (5 Sep), researchers release a large set of audiobooks for books in Project Gutenberg created automatically via generative AI with near-natural voice (7 Sep), a news outlet reports on a natural language system, demonstrated on 27 July, that can provide explanations for the conclusion-making of machine learning models for explainable AI (12 Sep), researchers report a production method for spider silk fibers from gene-edited transgenic silkworms for a sustainable alternative material six times stronger than Kevlar (20 Sep), a new generation of sleeping trains is presented amid a comeback of this transport technology in Europe as demand for more comfortable travel modes than overnight buses and sustainable transport rises (30 Sep).
According to 2023 V-Dem Democracy indices Ghana is ranked 67th electoral democracy worldwide and 10th electoral democracy in Africa. Ghana is a country in West Africa that is known for its cultural diversity, democratic government, and growing economy. The country has more than 30 million people and is home to many ethnic groups, languages, and traditions. Ghana is one of the world's leading producers of cocoa and is also rich on natural resources such as oil and gold. Besides economic importance, Ghana is recognized for its peaceful elections, historic landmarks, national parks and contributions to regional development in West Africa.
The electric bath for high-voltage static induction Oudin coil, a high-voltage induction coil, in use around 1900 Faradic battery, a device to provide localised electric stimulation Pulvermacher's chain, a wearable electrochemical device mostly used by quacks, in use during the second half of the 19th century. Leyden jars, an early form of capacitor, for storing electricity Electrostatic generators of various sorts
My fellow Americans, I'm pleased to tell you today that I've signed legislation that will outlaw Russia forever. We begin bombing in five minutes. The joke was a parody of the opening line of that day's speech:
=== Environment and Storage === Waterlogged wood should be in the environment that it is found in (and kept wet) until a stable treatment proposal in conversation with a professional conservator is decided. To limit mold growth, waterlogged wood should be stored with proper relative humidity and temperature that does not encourage mold. Waterlogged wood will retain its structure as long as it is wet.
Sources: en.wikipedia.org
=== Environmental === Various environmental risks have been studied in an attempt to understand what triggers β-cell destroying autoimmunity. Many aspects of environment and life history are associated with slight increases in type 1 diabetes risk; however, the connection between each risk and diabetes often remains unclear. Type 1 diabetes risk is slightly higher for children whose mothers are obese or older than 35, or for children born by caesarean section. Similarly, a child's weight gain in the first year of life, total weight, and BMI are associated with slightly increased type 1 diabetes risk. Dietary sugar intake was not related to the initial development of islet autoimmunity but was associated with the progression to type 1 diabetes. Animal studies and some large human studies have found small associations between type 1 diabetes risk and intake of gluten or dietary fiber; however, other large human studies have found no such association. Many potential environmental triggers have been investigated in large human studies and found to be unassociated with type 1 diabetes risk including duration of breastfeeding, time of introduction of cow milk into the diet, vitamin D consumption, blood levels of active vitamin D, and maternal intake of omega-3 fatty acids. A longstanding hypothesis is that certain viral infections may contribute to the development of type 1 diabetes. Much of this work has focused on enteroviruses, with Coxsackievirus B most strongly associated with islet autoimmunity and the onset of type 1 diabetes.
== History and production == Its industrial production was developed in Italy by Antonio Carpenè in collaboration with Enrico Comboni. Originally it was separated directly from the red wine (in which it is present for approximately 1% of the total) by precipitating it with basic lead acetate and obtaining a dark blue substance. Today, enocyanin is obtained from the peels of black grapes rich in anthocyanins (Italian cultivars "Ancellotta", "Colorino", "Sangiovese", "Lambrusco") by extraction in acidified water (often with citric or tartaric acid) at medium temperature (30–50°C) so as not to degrade the anthocyanins, sometimes with the addition of food-grade ethanol to improve yield and conservation. After separating the solids (seeds, fibers, and spent peels) using pressure filters or centrifugation, the extract is purified using ion exchange resins or membrane filtration, concentrated under low-temperature vacuum to preserve thermolabile compounds, and, if necessary, transformed into a powder through freeze-drying or spray-drying. The final product is stabilized with natural antioxidants and packaged in dark, airtight containers, often under an inert atmosphere. Classified as E163, enocyanin is used in the winemaking industry as a color enhancer and in the food and cosmetic industries for its intense pigmentation, excellent color stability in acidic environments, and its natural origin based on the recovery of winemaking byproducts. The starting pomace must be fresh and free of sulfur dioxide or other additives that could interfere with the extraction process.
With this new logo, Outback then went on an aggressive remodeling campaign, starting in 2008, renovating most of their locations, along with opening brand new ones, for a fresher, more modern look to their business model. This included the removal of their iconic neon signs for more energy efficient LEDs, and the switch from a dark, rustic feel to a brighter, more vibrant look. Today, few original-style Outback locations remain, with most of them either abandoned for newer locations, or renovated. On June 14, 2007, OSI Restaurant Partners completed a stock repurchase plan, and the company became privately held. In April 2012, Bloomin' Brands, the current owner of Outback Steakhouse, filed with the SEC to raise up to $300 million in an initial public offering. Bloomin' Brands, Inc. became a publicly traded company on NASDAQ under the ticker symbol "BLMN." Most Outback locations are corporately owned by Bloomin Brands. However, locations in California, Nevada, Arizona, Colorado, and New Mexico are separately owned by a corporate franchisee, Out West Restaurant Group. Outback Steakhouse currently operates over 1,000 locations worldwide, with 670 in the United States. In October 2025, Outback Steakhouse closed several locations across multiple U.S. states as part of a broader turnaround plan by its parent company, Bloomin' Brands.
== SN == sn – (s) Shona language (ISO 639-1 code) Sn – (s) Tin (Latin Stannum) SN (s) Senegal (ISO 3166 digram) Singapore (FIPS 10-4 country code) Snow (METAR Code) SuperNova Screen Name sna – (s) Shona language (ISO 639-2 code) SNAFU – (a) "Situation Normal — All Fouled/Fucked Up" SNAP – (p) Supernova/Acceleration Probe SNCB – (i) Société nationale des chemins de fer de Belgique (French for "Belgian Railways National Society", NMBS in Dutch) SNCF – (i) Société nationale des chemins de fer français (French for "French Railways National Society") snd – (s) Sindhi language (ISO 639-2 code) SND – (i) Standard Nomenclature Database SNE – (i) Synthetic Natural Environment SNES – Super Nintendo Entertainment System SNÉTA – (a) Syndicat national pour l'étude des transports aériens (French for "Aerial transport Study National Syndicate", 1919–1923) SNG – (i) Satellite News Gathering (television) SNL (i) Saturday Night Live (television) (i) Società Navigazione del Lago di Lugano SNM – (i) Special Nuclear Material SNMP – (i) Simple Network Management Protocol SNOBOL – (p) StriNg Oriented symBOlic Language SNP – (i) Single-nucleotide polymorphism SNR (i) SuperNova Remnant Signal-to-Noise Ratio SNRI – (i) Serotonin-Norepinephrine Reuptake Inhibitor SNS – (i) Spallation Neutron Source SNU – (i) Solar Neutrino Unit
Sources: en.wikipedia.org
where the final substitution, N0 = eC, is obtained by evaluating the equation at t = 0, as N0 is defined as being the quantity at t = 0. This is the form of the equation that is most commonly used to describe exponential decay. Any one of decay constant, mean lifetime, or half-life is sufficient to characterise the decay. The notation λ for the decay constant is a remnant of the usual notation for an eigenvalue. In this case, λ is the eigenvalue of the negative of the differential operator with N(t) as the corresponding eigenfunction.
==== Migration patterns ==== HIC can be useful in tracking animal migration. Animals with metabolically inert tissue (e.g. feathers or hair) synthesize that tissue using hydrogen from source water and food, but ideally do not incorporate subsequent water during migration. Because δD varies geographically, the difference between animal tissue δD and post-migration water δD, after accounting for the biological fractionation of assimilation, can provide information regarding animal movement. In monarch butterflies, for example, wing chitin is metabolically inert after it is built, so it can reflect the isotopic composition of the environmental water at the time and location of wing growth. This then creates a record of butterfly origin and can be used to determine migration distance. This approach can also be used in bats and birds, using hair and feathers, respectively. Since rainwater becomes depleted as elevation increases, this method can also track altitudinal migration. However, this is technically hard to do, and the resolution seems to be too poor to track small altitudinal changes. 2H is most useful in tracking movement of species between areas with large continental water variation, since species movement can be complicated by the similarity of local water δD between places. For example, source water from Baja California may have the same δD as water from Maine. Further, a proportion of the HIC in the tissue can exchange with water and complicate the interpretation of measurements.
When the PSOE took office the Spanish economy was in full expansion. One of the factors that had made this possible was the arrival of several million emigrants from Latin America, the Maghreb and Eastern Europe. But part of them were "undocumented" migrants so the government decided to proceed with a massive "regularization" throughout 2005 that affected about 700 000 people who obtained a residence permit by presenting a contract of employment. The PP accused the government of provoking a "call effect" of new emigrants. The integration of the four million emigrants who had arrived in Spain in the last 10 years – so that foreigners now accounted for almost 10% of the population – posed an enormous challenge for Spanish society. The main "engine" of economic growth was being the construction sector, driven by increased demand. However, much of it was the result of a speculative movement around the "brick" as many people did not buy the homes to inhabit them but to place their savings hoping to sell them later at a higher price. This was how the "Spanish property bubble" was fed. But in the summer of 2007, the outbreak of the subprime mortgage crisis in the United States had an immediate repercussion in Europe and especially in Spain, where housing prices stopped rising, the construction sector came to a standstill and this dragged down the economy as a whole which began to grow at a slower pace with the consequent increase in unemployment.
Sources: en.wikipedia.org
Dry powder is normally held at -20 degrees Celsius or below in a sealed, light-protected container with desiccant. Brief room-temperature handling during weighing is generally tolerated. Storage instructions vary between suppliers, so the accompanying certificate of analysis should be followed.
Reversed-phase HPLC establishes purity, while mass spectrometry confirms the expected molecular mass. Sequence confirmation may use tandem mass spectrometry or peptide mapping. A certificate of analysis typically reports these results alongside the analytical method applied.
In Russia it is a registered medicine available by prescription. In many other countries it is not approved for human use and is supplied only as a research chemical. Import and possession rules differ by jurisdiction, and buyers are responsible for checking local requirements.
Most published work uses intranasal application, either as drops or as a nasal spray. Injection routes appear in a smaller set of animal experiments. Oral use is uncommon in the literature because peptide breakdown and poor absorption limit this route.