Everything below concerns lyophilization. We keep the language plain, cite what the science says, and separate well-supported claims from open questions.
Last reviewed on 2026-08-01. Where a claim depends on a specific study, the study is described rather than over-claimed.
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.
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.
| Property | Value | Notes |
|---|---|---|
| Typical purity specification | 95 percent or higher by RP-HPLC | Area percentage of the main peak |
| Identity confirmation | Electrospray ionization mass spectrometry | Observed mass compared with the theoretical value near 751.9 Da |
| Recommended dry storage | -20 °C, desiccated | -80 °C for multi-year archival material |
| Solution handling | Prepare fresh; avoid long storage | Sterile filtration reduces microbial load |
| Common synonyms | TKPRPGP; TP-7 | Sequence code and laboratory designation used interchangeably |
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.
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.
Regulatory status differs sharply by region. Selank holds a Russian marketing authorization, where it is supplied mainly as nasal drops, while authorities elsewhere have not approved it for medical use. Material sold internationally is therefore usually labeled as a research chemical rather than a medicine. Peer-reviewed publications come predominantly from Russian laboratories, and sample sizes are generally small. Whether the compound produces comparable effects under independent, well-controlled replication remains an open question that the broader literature has not settled.
Selank is a synthetic heptapeptide developed in Russia as a structural analogue of tuftsin, a naturally occurring immunomodulatory tetrapeptide. Its sequence, Thr-Lys-Pro-Arg-Pro-Gly-Pro, keeps the tuftsin core at the N-terminus and appends a Pro-Gly-Pro tail. Researchers at the Institute of Molecular Genetics in Moscow synthesized the compound during the 1990s while searching for peptides with combined anxiolytic and immunomodulatory activity. The added tail was intended to resist enzymatic cleavage and prolong the molecule's presence in circulation.
The compound has a calculated molecular weight near 751.9 daltons and carries a net positive charge at physiological pH because of its arginine residue. It dissolves freely in water and in common aqueous buffers, and typically appears as a white or off-white lyophilized powder. The amide backbone makes the molecule susceptible to peptidases, which limits oral use and favors intranasal or parenteral routes. Nomenclature in the literature varies: the substance is also described by the sequence abbreviation TP-7 and by a Russian trade designation.
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.
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.
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.
Detailed statistics were not released by the Singapore government between 2000 and 2006. Singapore's Prime Minister Goh Chok Tong told the BBC in September 2003 that he believed there were "in the region of about 70 to 80" hangings in 2003. Two days later he retracted his statement, saying the number was in fact ten. In total, at the end of 2003, 19 people were hanged. While no information is issued on the race and ethnicity of death row inmates, it was noted in 2021, during an appeal from a number of Malay death row inmates who alleged racism on the part of the government, that there were a large number of Malays among those on death row, with only handfuls of other minority races. Between 2010 and 2021, Malays made up 66 of the 120 prosecuted for capital drug offences, with 76% of cases concluding with the death sentence. 50 out of 77 people sentenced to death between 2010 and 2021 were Malays, with a remaining 15 Indians, 10 Chinese and two from other races. Since 2010, of all the 77 sentenced to death, there were 14 Malaysians being condemned to death row, with eleven of them ethnic Indians, two Malays and one Chinese. Former chief executioner, Darshan Singh, who died from COVID-19 complications on 31 October 2021, stated that he had executed more than 850 people during his service, which began in 1959. When conducting the executions, he would use the phrase: "I am going to send you to a better place than this.
=== Adaptation strategies === Potato production is expected to decline in many areas due to hotter temperatures and decreased water availability. Conversely, production is predicted to become possible in high altitude and latitude areas where it has been limited by frost damage, such as in Canada and Russia. This will shift potato production to cooler areas, mitigating much of the projected decline in yield. However, this may trigger competition for land between potato crops and other land uses, mostly due to changes in water and temperature regimes. The other approach is through the development of varieties or cultivars which would be more adapted to altered conditions. This can be done through 'traditional' plant breeding techniques and genetic modification. These techniques allow for the selection of specific traits as a new cultivar is developed. Certain traits, such as heat stress tolerance, drought tolerance, fast growth/early maturation and disease resistance, may play an important role in creating new cultivars able to maintain yields under stressors induced by climate change. For instance, developing cultivars with greater heat stress tolerance would be critical for maintaining yields in countries with potato production areas near current cultivars' maximum temperature limits (e.g. Sub-Saharan Africa, India). Superior drought resistance can be achieved through improved water use efficiency (amount of food produced per amount of water used) or the ability to recover from short drought periods and still produce acceptable yields.
TDL Group recorded $1.48 billion in sales in 2005. Tim Hortons also operates locations on Canadian and American university campuses, including Brock University, Durham College, Georgian College, Algonquin College, Canisius College, York University, Toronto Metropolitan University, University at Buffalo, SUNY Plattsburgh, University of British Columbia, Memorial University of Newfoundland, University of Western Ontario, and Simon Fraser University. In March 2010, Tim Hortons announced further expansion on both sides of the Canada–US border to be completed by 2013. The plan called for 600 new stores in Canada (primarily in Quebec and Western Canada but also including smaller communities) and 300 new stores in the U.S. (primarily in its existing markets of Michigan, New York, and Ohio). It also called for expansion into such non-standard store locations as hospitals, universities, and airports, as well as extending its co-branding initiative with U.S. ice cream chain Cold Stone Creamery, which began in 2009, to cover 60 Canadian stores and 25 to 35 new and existing U.S. stores. It also included testing a new café/bake shop concept in at least 10 existing U.S. locations, including "enhanced finishes, fixtures, and seating areas" as well as an expansion of menu offerings. In 2010, Tim Hortons opened what were then its northernmost locations: three kiosks at NorthMart stores in Iqaluit, Nunavut. This expanded Tim Hortons' presence in every province and territory of Canada.
In the 12th and 13th centuries, crusades and conquest had subjugated Islamic territories in southern Italy, central Spain, and the Levant under European rule, and for the first time translations into Latin of the great works of Arabic and Greek scholars were made with the help of Jewish and Muslim scholars, especially in Toledo, which had fallen into Christian hands in 1085 and whose libraries had escaped destruction. Michael Scotus from Scotland made a Latin translation of Aristotle's work on animals from Arabic here around 1215, which was disseminated widely and was the first time in a millennium that this foundational text on zoology became available to Europeans. Falconry was popular in the Norman court in Sicily, and a number of works on the subject were written in Palermo. Emperor Frederick II of Hohenstaufen (1194–1250) learned about an falconry during his youth in Sicily and later built up a menagerie and sponsored translations of Arabic texts, among which the popular Arabic work known as the Liber Moaminus by an unknown author which was translated into Latin by Theodore of Antioch from Syria in 1240–1241 as the De Scientia Venandi per Aves, and also Michael Scotus (who had removed to Palermo) translated Ibn Sīnā's Kitāb al-Ḥayawān of 1027 for the Emperor, a commentary and scientific update of Aristotle's work which was part of Ibn Sīnā's massive Kitāb al-Šifāʾ.
Insulin is the principal hormone that regulates the uptake of glucose from the blood into most cells of the body, especially liver, adipose tissue and muscle, except smooth muscle, in which insulin acts via the IGF-1. Therefore, deficiency of insulin or the insensitivity of its receptors play a central role in all forms of diabetes mellitus. The body obtains glucose from three main sources: the intestinal absorption of food; the breakdown of glycogen (glycogenolysis), the storage form of glucose found in the liver; and gluconeogenesis, the generation of glucose from non-carbohydrate substrates in the body. Insulin plays a critical role in regulating glucose levels in the body. Insulin can inhibit the breakdown of glycogen or the process of gluconeogenesis, it can stimulate the transport of glucose into fat and muscle cells, and it can stimulate the storage of glucose in the form of glycogen. Insulin is released into the blood by beta cells (β-cells), found in the islets of Langerhans in the pancreas, in response to rising levels of blood glucose, typically after eating. Insulin is used by about two-thirds of the body's cells to absorb glucose from the blood for use as fuel, for conversion to other needed molecules, or for storage. Lower glucose levels result in decreased insulin release from the beta cells and in the breakdown of glycogen to glucose. This process is mainly controlled by the hormone glucagon, which acts in the opposite manner to insulin.
Sources: en.wikipedia.org
(WINNER) The contestant won the whole competition. ‡ The contestant won the Pre-Heat challenge. (WIN) The contestant won the Main Heat challenge. (HIGH) The contestant had one of the best dishes for that week. (IN) The contestant performed well enough to move on to the next week. (LOW) The contestant had one of the bottom dishes for that week, but was not eliminated. (OUT) The contestant was eliminated for worst dish.
=== Eating Disorder === To address the underlying eating disorder psychosocial interventions such as cognitive behavioral therapy, motivational therapy, problem-solving therapy, coping skills training, and family behavior therapy have all been shown to improve treatment adherence and achieve good glycemic control. It has been observed that addressing psychological needs improves HbA1c by 0.5%–1% in adults with T2DM. Useful therapies may involve cognitive behavioral therapy. Cognitive behavioral therapy focuses on changing unhealthy thinking surrounding the use of insulin. Family involvement and family therapy is helpful for long-term maintenance of good behaviors with taking insulin. A positive mindset to recovery, and connection with others who have experienced diabulimia, increases the probability of successful recovery.
== Therapeutic uses of neohormones == Relaxin has been shown to repair and reverse the symptoms associated with scleroderma (an autoimmune condition affecting connective tissues, blood vessels and internal organs) and fibrosis (thickening, hardening or build up of scar tissue). It also aids in the formation of new blood vessels (angiogenesis). This is also beneficial in wound management and healing. Other potential targets include the use of relaxin within human reproduction, such as in the preparation of the cervix for labour and birth and also as a drug target for breast cancer treatment although much more research is required in this area. Oxytocin is important for many different biological processes including social, maternal and sexual behaviours, pregnancy, milk production, and ejaculation. Agonists and antagonists of oxytocin – development of drugs that can utilise the receptor binding activity of oxytocin is an important therapeutic target as this could be applied to a range of conditions. Oxytocin plays a role in cell proliferation and differentiation in different ways depending on where it is in the body. Understanding the underlying pathways for different localities could help with development of cancer therapies.
Retinyl acetate (also called vitamin A acetate or all‑trans‑retinol acetate) is a synthetic, fat‑soluble acetate ester of retinol often used to supply vitamin A in food fortification, dietary supplements, and topical cosmetic products. Because the acetyl group protects the alcohol functionality, the compound is markedly more stable to heat, oxygen and light than free retinol, yet is rapidly hydrolyzed in the human intestine to active retinol after ingestion. Commercially, retinyl acetate is the second most common retinyl ester after retinyl palmitate.
== Clinical significance == Calcitonin assay is used in identifying patients with nodular thyroid diseases. It is helpful in making an early diagnosis of medullary carcinoma of thyroid. A malignancy of the parafollicular cells, i.e. medullary thyroid cancer (MTC), typically produces an elevated serum calcitonin level. Prognosis of MTC depends on early detection and treatment. Calcitonin also has significantly impacted molecular biology, as the gene encoding calcitonin was the first gene discovered in mammalian cells to be alternatively spliced, now known to be a ubiquitous mechanism in eukaryotes.
Sources: en.wikipedia.org
A mammal (from Latin mamma 'breast') is a vertebrate animal of the class Mammalia (). Mammals are characterized by the presence of milk-producing mammary glands for feeding their young, a broad neocortex region of the brain, fur or hair, and three middle ear bones. These characteristics distinguish them from reptiles and birds, from which their ancestors diverged in the Carboniferous period over 300 million years ago. Around 6,640 extant species of mammals have been described and divided into 27 orders. The study of mammals is called mammalogy. The largest orders of mammals, by number of species, are the rodents, bats, and eulipotyphlans (including hedgehogs, moles and shrews). The next three are the primates (including humans, monkeys and lemurs), the even-toed ungulates (including pigs, bovids and whales), and the Carnivora (including cats, dogs, and seals). Mammals are the only living members of Synapsida; this clade, together with Sauropsida (reptiles and birds), constitutes the larger Amniota clade. Early synapsids are referred to as "pelycosaurs." The more advanced therapsids became dominant during the Guadalupian. Mammals originated from cynodonts, an advanced group of therapsids, during the Late Triassic to Early Jurassic. Mammals achieved their modern diversity in the Paleogene and Neogene periods of the Cenozoic era, after the extinction of non-avian dinosaurs, and have been the dominant terrestrial animal group from 66 million years ago to the present.
=== Overdose === Most patients overdosing with venlafaxine develop only mild symptoms. Plasma venlafaxine concentrations in overdose survivors have ranged from 6 to 24 mg/L, while postmortem blood levels in fatalities are often in the 10–90 mg/L range. Published retrospective studies report that venlafaxine overdosage may be associated with an increased risk of fatal outcome compared to that observed with SSRI antidepressant products, but lower than that for tricyclic antidepressants. Healthcare professionals are advised to prescribe Effexor and Effexor XR in the smallest quantity of capsules consistent with good patient management to reduce the risk of overdose. It is usually reserved as a second-line treatment for depression due to a combination of its superior efficacy to the first-line treatments like fluoxetine, paroxetine and citalopram and greater frequency of side effects like nausea, headache, insomnia, drowsiness, dry mouth, constipation, sexual dysfunction, sweating and nervousness. There is no specific antidote for venlafaxine, and management is generally supportive, providing treatment for the immediate symptoms. Administration of activated charcoal can prevent absorption of the drug. Monitoring of cardiac rhythm and vital signs is indicated. Seizures are managed with benzodiazepines or other anticonvulsants. Forced diuresis, hemodialysis, exchange transfusion, or hemoperfusion are unlikely to be of benefit in hastening the removal of venlafaxine, due to the drug's high volume of distribution.
=== Loaded microbubble-enhanced focused ultrasound === Microbubbles are small "bubbles" of mono-lipids that are able to pass through the blood–brain barrier. They form a lipophilic bubble that can easily move through the barrier. One barrier to this however is that these microbubbles are rather large, which prevents their diffusion into the brain. This is counteracted by a focused ultrasound. The ultrasound increases the permeability of the blood–brain barrier by causing interference in the tight junctions in localized areas. This combined with the microbubbles allows for a very specific area of diffusion for the microbubbles, because they can only diffuse where the ultrasound is disrupting the barrier. The hypothesis and usefulness of these is the possibility of loading a microbubble with an active drug to diffuse through the barrier and target a specific area. There are several important factors in making this a viable solution for drug delivery. The first is that the loaded microbubble must not be substantially greater than the unloaded bubble. This ensures that the diffusion will be similar and the ultrasound disruption will be enough to induce diffusion. A second factor that must be determined is the stability of the loaded micro-bubble. This means is the drug fully retained in the bubble or is there leakage. Lastly, it must be determined how the drug is to be released from the microbubble once it passes through the blood–brain barrier. Studies have shown the effectiveness of this method for getting drugs to specific sites in the brain in animal models.
The natural progression of NAION following acute vision loss typically includes an improvement in visual acuity by 3 or more lines on the Early Treatment Diabetic Retinopathy Study (ETDRS) chart in 43% of those not receiving treatment. As the initial swelling of the optic disc subsides, optic atrophy generally develops within one to two months after onset. A retrospective diagnosis of optic atrophy due to previous ischemic optic neuropathy is often possible when a small optic disc is detected in both the affected and the opposite eye, and when other tests for potential causes of optic atrophy yield normal results. Following the ischemic damage to one optic disc, there exists a notable risk of involvement of the second eye. The recurrence rate of NAION in the same eye is approximately 6.4%. Data from the trial estimate this risk at about 15% over 5 years. In cases where the second eye also experiences NAION, there is no clear consensus regarding the correlation between the final visual outcomes.
== Carbon snake == Like concentrated sulfuric acid, oleum is such a strong dehydrating agent that if poured onto powdered glucose, or virtually any other sugar, it will draw the hydrogen elements of water out of the sugar in an exothermic reaction, leaving a residue of nearly pure carbon as a solid. This carbon expands outward, hardening as a solid black substance with gas bubbles in it. This reaction, often often dubbed a carbon snake, is sometimes used as a chemistry classroom experiment.
Sources: en.wikipedia.org
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.
A reported purity value reflects the share of the main peak in one chromatographic run and says nothing about identity. Confirming that the expected sequence is present requires a separate measurement such as mass spectrometry. Purity and identity are distinct questions.
A mass spectrum reports the molecular masses present in a sample and shows whether they match the value expected for selank, near 751.9 Da. It also flags common artifacts such as truncation or adduct formation. It does not establish correct stereochemistry or complete sequence order on its own.
Selank is a synthetic heptapeptide designed as a stabilized analog of the natural tetrapeptide tuftsin. It has been investigated mainly for anxiolytic and cognitive effects. It is not an approved pharmaceutical in most countries.