freeze-thaw is one of those subjects where the details matter more than the headlines. This page pulls together the background, the mechanisms, and the practical points readers ask about most.
Updated 2025-12-06. Numbers and descriptions here follow the published literature rather than marketing material.
Pharmacokinetic data are sparse and largely derived from animal work. After intranasal administration the peptide appears in plasma within minutes, and reported half-lives are short, on the order of minutes to tens of minutes. Degradation proceeds through ordinary proteolytic cleavage into constituent amino acids and smaller fragments. Direct evidence that intact Selank reaches brain tissue in meaningful amounts is limited, and the extent of blood-brain barrier penetration is debated. Some authors argue that fragments, not the parent peptide, carry much of the observed activity.
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.
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.
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.
| Property | Value | Notes |
|---|---|---|
| Primary route studied | Intranasal | Also examined parenterally in animal work |
| Reported plasma half-life | Minutes to tens of minutes | Values vary widely between reports |
| Main model systems | Rodent behavioural and cell assays | Human trials are few and small |
| Principal proposed targets | GABA-A receptor, GABA transaminase | Monoamine and neurotrophic pathways also reported |
| Evidence grade | Preliminary | Limited independent replication |
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.
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.
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.
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.
Before pregnancy, people with EDS may be recommended to have genetic counseling and to familiarize themselves with the risks pregnancy poses. Children with EDS should be given information about the disorder so they can understand why they should avoid contact sports and other physically stressful activities. Children should be taught that they should not demonstrate the unusual positions they can maintain due to loose joints, as this may cause early degeneration of the joints. Emotional support, along with behavioral and psychological therapy, can be useful. Support groups can be immensely helpful for people dealing with major lifestyle changes and poor health. Family members, teachers, and friends should be informed about EDS so they can accept and assist the child.
Implementing feed-stocks of high specific activity 99Mo solutions thus allowed for higher quality production and better separations of 99mTc from 99Mo on small alumina column using chromatography. Employing low-specific activity 99Mo under similar conditions is particularly problematic in that either higher Mo loading capacities or larger columns are required for accommodating equivalent amounts of 99Mo. Chemically speaking, this phenomenon occurs due to other Mo isotopes present aside from 99Mo that compete for surface site interactions on the column substrate. In turn, low-specific activity 99Mo usually requires much larger column sizes and longer separation times, and usually yields 99mTc accompanied by unsatisfactory amounts of the parent radioisotope when using γ-alumina as the column substrate. Ultimately, the inferior end-product 99mTc generated under these conditions makes it essentially incompatible with the current supply chain. In the last decade, cooperative agreements between the US government and private capital entities have resurrected neutron capture production for commercially distributed 99Mo/99mTc in the United States of America. The return to neutron-capture-based 99Mo has also been accompanied by the implementation of novel separation methods that allow for low-specific activity 99Mo to be utilized.
=== Gene therapy === Viral gene therapy involves artificially manipulating a virus to include a desirable piece of genetic material. Viral gene therapies using engineered plant viruses have been proposed to enhance crop performance and promote sustainable production.
== Critical analysis == In Posthumanism in the Novels of Kurt Vonnegut, ice-nine is described as an example of a wampeter in the fictional Bokononism religion, the pivot around which a karass, or a group of randomly interrelated people, revolves. Calling it both the cause of the apocalypse and one of the book's main sources of humor, the book argues that ice-nine sets the entire tone for the novel, which is "rendered inert" by its fragmentary structure and fundamental tension. The book also states that ice-nine reverses the normal hierarchy in which living organisms use water as a resource, becoming the "successor of organic life on planet Earth". Theoretical physicist and expert on string theory Leonard Susskind, in his book The Cosmic Landscape, calls Cat's Cradle and its use of ice-nine a "cautionary tale about madness and instability in a world full of nuclear weapons", as well as being based on the real scientific principle of metastability. Saying that: while in the real world liquid water at room temperature is stable, he explains that in Vonnegut's universe, normal water is only metastable, and since ice-nine is more stable than water, it will form naturally "sooner or later" even without the introduction of the seed crystal. It describes the fact that supercooled water takes on similar traits, and will completely freeze if a normal chunk of ice is introduced. The book also relates this to the metastability of vacuums in string theory and their ability to create a diverse universe. In Dr. Strangelove's America, Margot A.
By converting 1, 2-diacylglycerol into phosphatidylcholine Stimulating the synthesis of SAMe, which aids in membrane stabilization and reduces levels of arachidonic acid. This is especially important after an ischemia when arachidonic acid levels are elevated.
Sources: en.wikipedia.org
== Personal life == Morea resides in Bandra, Mumbai, in a home named Casa-Morea. He is known for maintaining a disciplined fitness routine and was recognized with the Iconic Health & Fitness Ambassador award at the Showbiz Icon Awards. He is reported to be fluent in several languages, including English, Hindi, Italian, Urdu, Kannada, French, and Portuguese.
=== GMod Tower === In July 2009, four developers working under the name "PixelTail Games" opened a Garry's Mod server called GMod Tower. GMod Tower was a network of servers, designed as a social media platform for users to play minigames with friends and socialise in a hub area. Within hours of the server's opening, the website for GMod Tower reached two million views. GMod Tower temporarily shut down between January and April 2012. PixelTail Games later expanded GMod Tower into Tower Unite, a standalone game that replaced GMod Tower upon its early access release in April 2016.
K2CO3 + CO2 + H2O → 2 KHCO3 CO2 de-scrubber: The above potassium carbonate solution (enriched with CO2) is then sent to the CO2 de-scrubber where CO2 is de-scrubbed by stepwise (usually two steps) flashing. The first step is done to remove the hydrocarbon gases, and the second step is employed to strip off CO2.
Susie Orbach (born 6 November 1946), psychotherapist, psychoanalyst, writer and social critic; daughter of Maurice Orbach, author of Fat is a Feminist Issue, married to author Jeanette Winterson. She is honoured in BBC'S 100 Women in 2013 and 2014. She was the therapist to Diana, Princess of Wales during the 1990s. Yotam Ottolenghi (born 14 December 1968), Israeli-British celebrity chef; journalist for The Guardian and Haaretz; author of several cookery books, including Ottolenghi: The Cookbook (2008), Plenty (2010), Jerusalem (2012). Moved to Europe after his service in Military Intelligence Directorate (Israel); in 2014, London Evening Standard remarked that Ottolenghi had "radically rewritten the way Londoners cook and eat"; in 2017 was guest judge on Masterchef Australia. Ilan Pappé, pro-Palestinian dissident Israeli-British scholar, writer and author of Ashkenazi origin, focusing on the history of Palestinian Nakba, intifada, insurgency, land ownership and rights and radical Anti-Zionism. Joseph Pardo (c. 1624 – 1677), hazzan and writer David Patrikarakos; journalist and war correspondent, author of War in 140 Characters: How Social Media Is Reshaping Conflict in the Twenty-First Century; wrote Nuclear Iran: Birth of An Atomic State which was named as a New York Times Editor's Choice and nominated for Total Politics Book Awards. Ruthie Pearlman, Orthodox Jewish Crime Writer and writer of Young Adult Fiction.
=== Medications === Burns can be very painful and a number of different options may be used for pain management. These include simple analgesics (such as ibuprofen and acetaminophen) and opioids such as morphine. Benzodiazepines may be used in addition to analgesics to help with anxiety. During the healing process, antihistamines, massage, or transcutaneous nerve stimulation may be used to aid with itching. Antihistamines, however, are only effective for this purpose in 20% of people. There is tentative evidence supporting the use of gabapentin and its use may be reasonable in those who do not improve with antihistamines. Intravenous lidocaine requires more study before it can be recommended for pain. Intravenous antibiotics are recommended before surgery for those with extensive burns (>60% TBSA). As of 2008, guidelines do not recommend their general use due to concerns regarding antibiotic resistance and the increased risk of fungal infections. Tentative evidence, however, shows that they may improve survival rates in those with large and severe burns. Erythropoietin has not been found effective to prevent or treat anemia in burn cases. In burns caused by hydrofluoric acid, calcium gluconate is a specific antidote and may be used intravenously and/or topically. Recombinant human growth hormone (rhGH) in those with burns that involve more than 40% of their body appears to speed healing without affecting the risk of death. The use of steroids is of unclear evidence.
Sources: en.wikipedia.org
== History == In the late 19th century, most vacuums were created using a Sprengel pump, which had the advantage of being very simple to operate, and capable of achieving quite good vacuum given enough time. Compared to later pumps, however, the pumping speed was very slow and the vapor pressure of the liquid mercury limited the ultimate vacuum. Following his invention of the molecular pump, Wolfgang Gaede invented the diffusion pump in 1915, and originally used elemental mercury as the working fluid. After its invention, the design was quickly commercialized by Leybold. It was then improved by Irving Langmuir, and W. Crawford. C.R. Burch described the possibility of using silicone oil in 1928.
5 December Junior doctors in England will stage further strike action after rejecting the latest pay offer, the British Medical Association confirms, with a three-day strike scheduled to begin on 20 December and a six-day strike scheduled to begin on 3 January 2024. The Scottish Prison Service issues new guidelines on transgender prisoners. Trans women who have hurt or threatened women or girls will not be sent to a female prison unless there are "exceptional" circumstances. Jesse Darling is announced as the winner of the 2023 Turner Prize. 6 December Boris Johnson, who served as prime minister from 2019 to 2022, appears before the COVID-19 inquiry and is questioned by Hugo Keith, counsel to the inquiry. He apologises for the "pain and the loss and the suffering" people experienced during the pandemic. His comments are interrupted by protesters, who are ordered to leave the inquiry room. Robert Jenrick resigns as immigration minister after the government publishes an emergency Rwanda bill. 7 December Figures released by Halifax Bank indicate house prices in the UK rose by 0.5% in November 2023. Culture Secretary Lucy Frazer confirms the TV licence fee will increase by £10.50 from £159 to £169.50 from 1 April 2024. Serial killer Steve Wright is arrested for the September 1999 murder of Victoria Hall. 8 December A letter to MPs from Sir Matthew Rycroft, the Permanent Under-Secretary of State of the Home Office, says that £240m has been paid so far to Rwanda for the Rwanda asylum plan, with a further £50m to be paid in 2024.
Chemical elements data references List of chemical elements – atomic mass, atomic number, symbol, name List of minerals – Minerals Electron configurations of the elements (data page) – electron configuration, electrons per shell Densities of the elements (data page) – density (solid, liquid, gas) Electron affinity (data page) – electron affinity Melting points of the elements (data page) – melting point Boiling points of the elements (data page) – boiling point Critical points of the elements (data page) – critical point Heats of fusion of the elements (data page) – heat of fusion Heats of vaporization of the elements (data page) – heat of vaporization Heat capacities of the elements (data page) – heat capacity Vapor pressures of the elements (data page) – vapor pressure Electronegativities of the elements (data page) – electronegativity (Pauling scale) Ionization energies of the elements (data page) – ionization energies (in eV) and molar ionization energies (in kJ/mol) Atomic radii of the elements (data page) – atomic radius (empirical), atomic radius (calculated), van der Waals radius, covalent radius Electrical resistivities of the elements (data page) – electrical resistivity Thermal conductivities of the elements (data page) – thermal conductivity Thermal expansion coefficients of the elements (data page) – thermal expansion Speeds of sound of the elements (data page) – speed of sound Elastic properties of the elements (data page) – Young's modulus, Poisson ratio, bulk modulus, shear modulus Hardnesses of the elements (data page) – Mohs hardness, Vickers hardness, Brinell hardness Abundances of the elements (data page) – Earth's crust, sea water, Sun and solar system List of oxidation states of the elements – oxidation states List of compounds List of CAS numbers by chemical compound List of Extremely Hazardous Substances List of inorganic compounds List of organic compounds List of alkanes List of alloys Other List of thermal conductivities List of purification methods in chemistry List of unsolved problems in chemistry
Agricultural runoff is a major pathway through which CEC enter the environment. Compounds like pesticides and pharmaceuticals from fertilizers are carried by water from farms into their surrounding areas soil and water bodies. Then runoff happens after rainfall or irrigation, which causes an influx of chemicals to leak out of the soil where they were dumped and into rivers, lakes, and groundwater. The runoff can contain a CEC's which are not regulated or whose environmental impacts are not well understood, contributing to the pollution of aquatic ecosystems, and potentially affecting human water sources. A significant challenge is monitoring levels of CEC in bodies of water. A nationwide survey revealed that soil erosion, nutrient loss, and pesticide runoff from America's vast agricultural lands are leading causes of water quality pollution. Approximately 46% of rivers and streams in the United States have conditions which are harmful to aquatic life. Additionally, only about 28% of these water bodies are rated as 'healthy' based on their biological communities.
Sources: en.wikipedia.org
Reports describe modulation of GABA signalling, changes in monoamine turnover and effects on neurotrophic factor expression. These observations come mainly from animal and cell studies. A single unifying mechanism has not been demonstrated.
The peptide enters plasma rapidly and is broken down by ordinary proteases into amino acids and shorter fragments. Reported half-lives are short. Whether meaningful amounts of the intact molecule reach the brain is an open question.
Most clinical reports are small, published in Russian and not independently replicated. English-language reviews highlight the absence of large randomised trials. Conclusions about efficacy should be treated as provisional.
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.