Everything below concerns reversed-phase HPLC. We keep the language plain, cite what the science says, and separate well-supported claims from open questions.
Updated 2026-02-20. Numbers and descriptions here follow the published literature rather than marketing material.
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.
Dry powder is normally held at -20 degrees Celsius or lower, in a sealed container with desiccant and protection from light. Reconstituted solutions are usually kept at 2 to 8 degrees Celsius for short periods and frozen for longer ones. Proline residues at several positions are generally associated with some resistance to peptidase attack, but chemical stability still declines at neutral to alkaline pH and at elevated temperature. Exact shelf-life figures are product-specific and are not standardised across suppliers.
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.
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.
| 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 |
Identity and purity of selank are established with reversed-phase high-performance liquid chromatography coupled to mass spectrometry. The peptide elutes from C18 columns with acetonitrile gradients in water containing trifluoroacetic acid or formic acid, and detection is usually performed by ultraviolet absorbance near 214 nm. Electrospray ionization in positive mode gives a doubly protonated ion near m/z 377, consistent with a mass of about 752 Da. Amino acid analysis or tandem mass spectrometry of fragment ions confirms the sequence. Because the molecule has no aromatic residues, it lacks a usable 280 nm chromophore, so low-wavelength detection or mass spectrometry is required.
Peptide bonds in selank are susceptible to hydrolysis under strongly acidic or basic conditions, and the terminal proline residues are vulnerable to exopeptidase activity in biological samples. Lyophilized powder stored dry at -20 °C typically remains stable for extended periods, whereas aqueous solutions degrade faster and may lose measurable purity within days to weeks depending on pH, temperature, and microbial load. Repeated freeze-thaw cycles promote aggregation and adsorption to container surfaces. For analytical work, solutions are usually prepared fresh, kept cold, and used within a single working day.
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.
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.
The 2014 State Department's annual Trafficking in Persons (TIP) report appeared to classify the Khobragade incident as an example of human trafficking, stating: "An Indian consular officer at the New York consulate was indicted in December 2013 for visa fraud related to her alleged exploitation of an Indian domestic worker." In response, India has shown no urgency to allow visits to India by the newly appointed US anti-human trafficking ambassador Susan P. Coppedge and the US special envoy for LGBT rights Randy Berry. Under Section 377 of the Indian Penal Code homosexuality was illegal in India. Indian Ambassador to the US, Arun K. Singh reiterated India's commitment to work within an international framework to tackle the problem of trafficking but rejected any "unilateral assessments" by another country saying "We will never accept it" and downplayed the importance of the visits: "When you ask a U.S. official when somebody will be given a visa, they always say 'we will assess when visa is applied for.' ... I can do no better than to reiterate the U.S. position." In February 2016, the Obama administration notified the US Congress that it intended to provide Pakistan eight nuclear-capable F-16 fighters and assorted military goods including eight AN/APG-68(V)9 airborne radars and eight ALQ-211(V)9 electronic warfare suites despite strong reservations from US lawmakers regarding the transfer of any nuclear weapons capable platforms to Pakistan. Shashi Tharoor, an elected representative from the Congress party in India, questioned the substance of India–U.S.
=== Pyrimidine catabolism === Cytosine and uracil are converted into beta-alanine, which is further processed into malonyl-CoA, a key precursor for fatty acid synthesis and other metabolic pathways. Thymine, on the other hand, is converted into β-aminoisobutyric acid, which is then used to form methylmalonyl-CoA. The remaining carbon skeletons, such as acetyl-CoA and succinyl-CoA, can be further oxidized in the citric acid cycle. Pyrimidine degradation ultimately results in the formation of ammonium, water, and carbon dioxide. The ammonium can then enter the urea cycle, which takes place in both the cytosol and mitochondria of cells. Pyrimidine bases can also be salvaged. For example, the uracil base can be combined with ribose-1-phosphate to form uridine monophosphate (UMP). A similar reaction occurs with thymine and deoxyribose-1-phosphate. Deficiencies in enzymes involved in pyrimidine catabolism can lead to diseases such as Dihydropyrimidine dehydrogenase deficiency, which causes neurological impairments.
Cecropin A Peptide Sequence (KWKLFKKIEKVGQNIRDGIIKAGPAVAVVGQATQIAK). Secondary structure includes two α helices. At low peptide to lipid ratios ion channels are formed, at high peptide to lipid ratios pores are formed. Cecropin B Peptide Sequence (KWKVFKKIEKMGRNIRNGIVKAGPAIAVLGEAKAL). Secondary structure includes two α helices. CECD from Aedes aegypti (Yellowfever mosquito). Papiliocin from Papilio xuthus (a butterfly) Cecropin P1 Peptide Sequence (SWLSKTAKKLENSAKKRISEGIAIAIQGGPR). An antibacterial peptide from Ascaris suum, a parasitic nematode that resides in the pig intestine, also belongs to this family.
==== By RuBisCO activase ==== In plants and some algae, another enzyme, RuBisCO activase (Rca, GO:0046863, P10896), is required to allow the rapid formation of the critical carbamate in the active site of RuBisCO. This is required because ribulose 1,5-bisphosphate (RuBP) binds more strongly to the active sites of RuBisCO when excess carbamate is present, preventing processes from moving forward. In the light, RuBisCO activase promotes the release of the inhibitory (or — in some views — storage) RuBP from the catalytic sites of RuBisCO. Activase is also required in some plants (e.g., tobacco and many beans) because, in darkness, RuBisCO is inhibited (or protected from hydrolysis) by a competitive inhibitor synthesized by these plants, a substrate analog 2-carboxy-D-arabitinol 1-phosphate (CA1P). CA1P binds tightly to the active site of carbamylated RuBisCO and inhibits catalytic activity to an even greater extent. CA1P has also been shown to keep RuBisCO in a conformation that is protected from proteolysis. In the light, RuBisCO activase also promotes the release of CA1P from the catalytic sites. After the CA1P is released from RuBisCO, it is rapidly converted to a non-inhibitory form by a light-activated CA1P-phosphatase. Even without these strong inhibitors, once every several hundred reactions, the normal reactions with carbon dioxide or oxygen are not completed; other inhibitory substrate analogs are still formed in the active site.
Sources: en.wikipedia.org
It is used in the production of various organic peroxides and hydroperoxides. Dibenzoyl peroxide is a high-volume example. Peroxy acids, such as peracetic acid and meta-chloroperoxybenzoic acid also are produced using hydrogen peroxide. Hydrogen peroxide has been used for creating organic peroxide-based explosives, such as acetone peroxide. It is used as a Radical initiator in radical polymerization processes. Hydrogen peroxide reacts with certain di-esters, such as phenyl oxalate ester (cyalume), to produce chemiluminescence; this application is most commonly encountered in the form of glow sticks.
=== First Supply Chain Management Certification === The term Supply Chain Management (SCM) was coined in the early eighties (1982) by Booz Allen Consultant, Keith Oliver, but remained only a buzzword for many years. The holistic concept of a cross-functional set of processes aimed to fulfill the customer's needs, started to make sense to companies, consultants and academics in the early nineties. It was until the decade's end, when technology enabled Business Process Integration throughout each company and extended to other companies, that the term SCM was widely adopted. SCM finally grew to become normal science in the first decade of the millennium. ISCEA's founding members identified the need of a professional SCM certification organization and developed the Certified Supply Chain Manager (CSCM) certification program. It was the first certification program developed by ISCEA and was launched simultaneously with ISCEA's initial website in early 2003. There are other professional knowledge certifying bodies currently offering SCM certification. Some of them founded many years before ISCEA. But their SCM certification programs were released after ISCEA's CSCM:
==== Alcohol-ether treatment ==== This treatment follows the similar treatment of the PEG solution but instead of replacing the cells with another solution, the cells are replaced with alcohol and when the alcohol evaporates the cell and overall object is dehydrated. As a volatile solvent treatment option, the impact on the health and safety on the workplace must be considered.
Sources: en.wikipedia.org
Body hair characteristics such as thickness and length vary across human populations, some people have less pronounced body hair and others have more conspicuous body hair characteristics. Each culture of human society developed social norms relating to the presence or absence of body hair, which has changed from one time to another. Different standards of human physical appearance and physical attractiveness can apply to women and men. People whose hair falls outside a culture's aesthetic body image standards may experience real or perceived social acceptance problems, psychological distress and social pressure. For example, for women in several societies, exposure in public of body hair other than head hair, eyelashes and eyebrows is generally considered to be unaesthetic, unattractive and embarrassing. With the increased popularity in many countries of women wearing fashion clothing, sportswear and swimsuits during the 20th century and the consequential exposure of parts of the body on which hair is commonly found, there has emerged a popularization for women to remove visible body hair, such as on legs, underarms and elsewhere, or the consequences of hirsutism and hypertrichosis. In most of the Western world, for example, the vast majority of women regularly shave their legs and armpits, while roughly half also shave hair that may become exposed around their bikini pelvic area (often termed the "bikini line").
== External links == CD38+Antigens at the U.S. National Library of Medicine Medical Subject Headings (MeSH) Human CD38 genome location and CD38 gene details page in the UCSC Genome Browser. GeneCard CD38 [1] Overview of all the structural information available in the PDB for UniProt: P28907 (ADP-ribosyl cyclase/cyclic ADP-ribose hydrolase 1) at the PDBe-KB. CD38
== Background == Founded in 1989 by Jaba Ioseliani, the Mkhedrioni presented itself as the heir to historic Georgian guerrilla groups who fought Iranian and Ottoman occupiers. The group's name literally means "horsemen", but in Georgian it has a meaning closer to "knights" (this alternative translation has occasionally been used). Each member of the organization would take an oath to defend Georgia's people, the Georgian Orthodox and Apostolic Church and Georgia's land, and wore a medallion with a scene of Saint George slaying the dragon on one side and the bearer's name and blood type on the other. The establishment of the Mkhedrioni took place as Georgia moved towards independence in the final years of the Soviet Union. Relations between Georgian nationalists and the country's national minorities, especially the Abkhaz and Ossetians, were difficult at best even during Soviet rule and grew more tense during the rise to power of the nationalist dissident Zviad Gamsakhurdia. The Mkhedrioni was one of a number of nationalist paramilitary groups established during this period as a counterbalance to similar paramilitary organisations set up by rival nationalists elsewhere in Georgia. The Mkhedrioni's members gained an unpleasant reputation as heavily armed thugs who engaged in violent intimidation of their rivals. They were highly visible, wearing what amounted to a uniform of jeans, sweaters and jackets, topped off by sunglasses (even worn indoors). Leaders wore Armani suits bulging with guns, according to one author.
==== Milestones of 1,500 RBI, 1,500 runs scored and 200 stolen bases (2004) ==== When he hit his sixth career grand slam against Milwaukee on April 9, 2004, Bagwell tied a club record. He recorded his 200th career stolen base on August 30 against Cincinnati to become the tenth player in MLB history to reach that plateau while hitting 400 home runs. On September 18, 2004, Bagwell collected his 1,500th career RBI with a single in the third inning against the Brewers. Two innings later, he homered for his 1,500th run scored, becoming just the 29th player in MLB history and the first Astro to reach both milestones. Bagwell finished with 27 home runs, stopping a streak of eight consecutive seasons with at least 30, but extending a streak of 12 with at least 20. The Astros faced the Braves in the playoffs for the fourth time in Bagwell's career in the 2004 NLDS. In Game 3, on October 7, he hit his first career postseason home run off Mike Hampton in the first inning in a 4–2 extra-inning loss. After three failed attempts to advance past the first round of the playoffs earlier in Bagwell's career, losing to Atlanta in 1997, 1999, and 2001, and seven overall in 43 years of franchise history, the Astros defeated the Braves for their first-ever playoff series win. The quartet dubbed the "Killer B's," this time including Carlos Beltrán and Lance Berkman, ignited the Astros' offense, batting .395 (34-for-86) with eight home runs, 21 RBI and 24 runs scored. The Astros scored an NLDS-record 36 runs in all and Bagwell batted .318 with two home runs and five RBI.
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.
The most common approach combines reverse-phase liquid chromatography with mass spectrometry. Chromatography separates the components while mass spectrometry confirms the molecular mass. Peptide sequencing or tandem mass analysis can further verify the amino acid order.