A practical reference on anxiolytic: what it is, how it behaves, what the literature reports, and where the honest uncertainties sit.
Reviewed 2026-01-14. Anything still debated is marked as such rather than presented as settled.
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.
Quantification in biological matrices relies on liquid chromatography coupled to tandem mass spectrometry with stable-isotope internal standards. Low plasma concentrations and adsorption to container surfaces both complicate measurement. Solid-phase extraction is often needed to reduce matrix interference before injection. Reported limits of quantification differ widely between laboratories, which makes direct comparison of pharmacokinetic results difficult and limits meta-analysis.
Solubility behavior is a practical concern for handling. Selank dissolves readily in water and in common aqueous buffers, which simplifies preparation of working solutions. The choice of solvent, ionic strength, and pH can influence aggregation over time, particularly at higher concentrations. Aqueous solutions are typically sterile-filtered before use. Because stability depends on several variables, storage and handling notes should be treated as general guidance rather than fixed rules, and specific values are best confirmed against a certificate of analysis for each batch.
Characterization of Selank in a laboratory setting relies on standard peptide methods. Reverse-phase high-performance liquid chromatography separates the target from related impurities and provides a purity figure, commonly reported as 95 percent or higher. Mass spectrometry, typically electrospray ionization or matrix-assisted laser desorption, confirms the molecular mass and helps detect truncation or modification. Amino acid analysis can verify composition when a sequence-level check is needed. These techniques together establish identity and purity for a given lot.
| 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 |
Tuftsin, the parent structure, is a naturally occurring immunomodulatory tetrapeptide released from the Fc region of immunoglobulin G by spleen enzymes. Selank extends this four-residue sequence with three additional amino acids. The stated rationale is that the added tail slows enzymatic breakdown and may influence receptor interactions. How the full heptapeptide behaves at the molecular level is not firmly established, and proposed mechanisms often involve indirect modulation of neurotransmitter or immune signaling rather than a single defined target.
Selank is a synthetic heptapeptide developed in Russia. Its sequence is Thr-Lys-Pro-Arg-Pro-Gly-Pro, a seven-residue chain built around the natural tetrapeptide tuftsin. Researchers at the Institute of Molecular Genetics of the Russian Academy of Sciences first described the compound in the mid-1990s. The design combined the tuftsin core with an added Pro-Gly-Pro tail, a modification intended to extend the molecule's stability in biological fluids. Published work on the peptide has appeared mainly in Russian-language journals.
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.
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.
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, frequently abbreviated as TKPRPGP. It was designed as a structural analogue of tuftsin, a naturally occurring tetrapeptide released by enzymatic cleavage of the immunoglobulin heavy chain. The two additional proline residues at the C-terminal end extend the parent chain and change how the molecule behaves in solution. The free peptide has a calculated molecular mass of approximately 751.9 g/mol and is generally supplied as a lyophilised white to off-white powder.
Methylene blue is used in endoscopic polypectomy as an adjunct to saline or epinephrine, and is used for injection into the submucosa around the polyp to be removed. This allows the submucosal tissue plane to be identified after the polyp is removed, which is useful in determining if more tissue needs to be removed or if there is a high risk for perforation. Methylene blue is also used as a dye in chromoendoscopy, and is sprayed onto the mucosa of the gastrointestinal tract to identify dysplasia, or pre-cancerous lesions. Intravenously injected methylene blue is readily released into the urine. In surgeries such as sentinel lymph node dissections, methylene blue can be used to visually trace the lymphatic drainage of tested tissues. Similarly, methylene blue is added to bone cement in orthopedic operations to provide easy discrimination between native bone and cement. Additionally, methylene blue accelerates the hardening of bone cement, increasing the speed at which bone cement can be effectively applied. Methylene blue is used as an aid to visualisation/orientation in several medical devices, including a surgical sealant film. It can also be used during gastrointestinal surgeries (such as bowel resection or gastric bypass) to test for leaks. It is sometimes used in cytopathology, in mixtures including Wright-Giemsa and Diff-Quik. It confers a blue color to both nuclei and cytoplasm, and makes the nuclei more visible. When methylene blue is "polychromed" (oxidized in solution or "ripened" by fungal metabolism, as originally noted in the thesis of Dr. D. L.
=== Tt dependence on ELP structure === The transition temperature of an ELP depends to a certain extent on the identity of the "X" residue found at the fourth position of the pentapeptide monomeric unit. Residues that are highly hydrophobic, such as leucine and phenylalanine, tend to decrease the transition temperature. On the other hand, residues that are highly hydrophilic, such as serine and glutamine, tend to increase the transition temperature. The presence of a potentially charged residue at the "X" position will determine how the ELP responds to varying pHs, with glutamic acid and aspartic acid raising the Tt at pH values in which the residues are deprotonated and lysine and arginine raising the Tt at pH values in which the residues are protonated. The pH needs to be compatible with the charged states of these amino acids in order to raise the Tt. Also higher molecular mass ELPs and higher concentrations of ELPs in solution make it much easier for the polymer to form aggregates, in effect lowering the experimental Tt.
== External links == International Union of Pure and Applied Chemistry Archived 2007-10-31 at the Wayback Machine IUPAC Nomenclature Home Page, see especially the "Gold Book" containing definitions of standard chemical terms Interactive Mind Map of Chemistry / Chemical energetics Archived 2018-01-27 at the Wayback Machine
Masa or masa de maíz (English: ; Spanish pronunciation: [ˈmasa]) is a dough made from ground nixtamalized corn. It is used for making corn tortillas, gorditas, tamales, pupusas, and many other Latin American dishes. It is dried and powdered into a flour form called harina de maíz or masa harina. Masa is reconstituted by mixing with water before using it in cooking. In Spanish, masa translates simply to "dough" and harina translates to "flour", but the name masa harina does not follow Spanish grammar and the term does not exist in Spanish.
Xenobiotic metabolism (from the Greek xenos "stranger" and biotic "related to living beings") is the set of metabolic pathways that modify the chemical structure of xenobiotics, which are compounds foreign to an organism's normal biochemistry, such as drugs and poisons. These pathways are a form of biotransformation present in all major groups of organisms, and are considered to be of ancient origin. These reactions often act to detoxify poisonous compounds; however, in cases such as in the metabolism of alcohol, the intermediates in xenobiotic metabolism can themselves be the cause of toxic effects. Xenobiotic metabolism is divided into three phases. In phase I, enzymes such as cytochrome P450 oxidases introduce reactive or polar groups into xenobiotics. These modified compounds are then conjugated to polar compounds in phase II reactions. These reactions are catalysed by transferase enzymes such as glutathione S-transferases. Finally, in phase III, the conjugated xenobiotics may be further processed, before being recognised by efflux transporters and pumped out of cells. The reactions in these pathways are of particular interest in medicine as part of drug metabolism and as a factor contributing to multidrug resistance in infectious diseases and cancer chemotherapy. The actions of some drugs as substrates or inhibitors of enzymes involved in xenobiotic metabolism are a common reason for hazardous drug interactions.
Sources: en.wikipedia.org
5-HT2C receptor agonists are a class of drugs that activate 5-HT2C receptors. They have been investigated for the treatment of a number of conditions including obesity, psychiatric disorders, sexual dysfunction and urinary incontinence. The 5-HT2C receptors are one of three subtypes that belong to the serotonin 5-HT2 receptor subfamily along with 5-HT2A and 5-HT2B receptors. The development of 5-HT2C agonists has been a major obstacle, because of severe side effects due to a lack of selectivity. Activation of 5-HT2A receptors can induce hallucinations, and the activation of 5-HT2B receptors has been implicated in cardiac valvular insufficiency and possibly in pulmonary hypertension.
The presence of breast implants currently presents no contraindication to breast feeding, and there is no evidence to support that the practice may present health issues to a breastfeeding infant. Women with breast implants may have functional breast-feeding difficulties; mammoplasty procedures that feature periareolar incisions are especially likely to cause breastfeeding difficulties. Surgery may also damage the lactiferous ducts and the nerves in the nipple-areola area. Functional breastfeeding difficulties arise if the surgeon cut the milk ducts or the major nerves innervating the breast, or if the milk glands were otherwise damaged. Milk duct and nerve damage are more common if the incisions cut tissue near the nipple. The milk glands are most likely to be affected by subglandular implants and by large-sized breast implants, which pinch the lactiferous ducts and impede milk flow. Small-sized breast implants and submuscular implantation cause fewer breast-function problems; however, it is impossible to predict whether a woman who undergoes breast augmentation will be able to successfully breast feed since some women are able to breast-feed after periareolar incisions and subglandular placement and some are not able to after augmentation using submuscular and other types of surgical incisions.
He was succeeded by Robin Dutt, who himself left the club for Bayer Leverkusen in 2011. On 10 May 2009, Freiburg secured promotion into the Bundesliga once again, beating TuS Koblenz in an away game 5–2.
=== Value Menu === In 2012, A&W introduced its first value burger, the Buddy Burger, and its double patty variant, the Double Buddy burger. Both can be ordered with or without cheese. The release of the Buddy burger made A&W more competitive against McDonald's, who already had value burgers like the McDouble. In 2015, A&W piloted the new Chicken Buddy burger at some select locations. It was successful and was added to the value menu permanently in 2016.
=== Vascular === Elabela is expressed by midline tissues (such as the notochord in zebrafish and neural tube in mammals) during organogenesis. There it serves as a chemoattractant to angioblasts expressing APLNR at their cell surface. This participates in the formation of the first and secondary vessels of the vascular system.
Sources: en.wikipedia.org
== Historical note == An. gambiae invaded northeastern Brazil in 1930, which led to a malaria epidemic in 1938/1939. The Brazilian government assisted by the Rockefeller Foundation in a programme spearheaded by Fred Soper eradicated these mosquitoes from this area. This effort was modeled on the earlier success in eradication of Aedes aegypti as part of the yellow fever control program. The exact species involved in this epidemic has been identified as An. arabiensis.
==== Education ==== The educational field also was a major way for adopting Western-style music. The educational reforms were led by Isawa Shūji (1851–1917) and Luther Whiting Mason (1828–1896). In 1880, the Music Research Institute in Tokyo (Ongaku Torishirabe Gakari), headed by Izawa Shuji, was founded. The Institute had three main tasks: 1) to introduce compulsory music teaching in schools, to introduce Western-style songs; 2) to train music teachers for the further development of professional musical activities; 3) to create music score collections for children, in which Japanese and Western style music elements could be combined. Thus, the first music scores "The First Collection for Primary School" was published in 1881. The newly educated music teachers organized lessons in singing, music theory, playing musical instruments (koto, kokyū, piano, organ and violin). In 1887, the Music Research Institute was reformed into Tokyo Academy of Music, which gave the Institution a new status and contributed to its further development. Western music was regarded as an essential contributory factor for modernization. The new curriculum was improved, and the number and quality of the musical events increased. Tokyo Academy of Music became the first Western-style music educational establishment in Japan. This was the nascence of schools teaching composition in the Western style in Japan, the genesis of an opera tradition in Japan, and laid the foundations for the Japanese formal tradition of familiarization with Western music.
Recognition of its prevalence and consequences has led to governments and non-government organizations promoting vitamin A fortification of foods and creating programs that administer large bolus-size oral doses of vitamin A to young children every four to six months. In 2008, the World Health Organization estimated that vitamin A supplementation over a decade in 40 countries averted 1.25 million deaths due to vitamin A deficiency. A Cochrane review reported that vitamin A supplementation is associated with a clinically meaningful reduction in morbidity and mortality in children ages six month to five years of age. All-cause mortality was reduced by 14%, and incidence of diarrhea by 12%. However, a Cochrane review by the same group concluded there was insufficient evidence to recommend blanket vitamin A supplementation for infants one to six months of age, as it did not reduce infant mortality or morbidity.
The Haitian Revolution began in 1791, just before the French Revolutionary Wars, and continued until 1804. France's defeat resulted in the independence of Saint-Domingue and led Napoleon to sell the territory making up the Louisiana Purchase to the United States.
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.
Reverse-phase HPLC is the usual method and gives a percentage purity value. Mass spectrometry then confirms the molecular mass. Together they provide a basic identity and purity profile for a lot.