If you have been reading about Certificate of analysis 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 2025-08-29. Where a claim depends on a specific study, the study is described rather than over-claimed.
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.
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.
| Property | Value | Notes |
|---|---|---|
| Common route | Intranasal | Also injected in some animal work |
| Solubility class | Freely soluble in water | Solid form is hygroscopic |
| Typical storage | About -20 degrees Celsius | Keep desiccated and dark |
| Purity method | Reverse-phase HPLC | Reported as area percent |
| Confirmatory method | Mass spectrometry | Verifies expected molecular mass |
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 not a naturally occurring peptide and has no known endogenous counterpart in human physiology. Russian-language sources frequently call it TP-7, while English-language sources use the name Selank almost exclusively. Database indexing is uneven, partly because early reports appeared in regional journals that are not widely cataloged. Some summaries describe the material as a tuftsin analog and others as a synthetic heptapeptide; the labels overlap rather than conflict. Citing the primary sequence resolves ambiguity more reliably than the research or trade name alone.
Selank is a synthetic heptapeptide with the sequence Thr-Lys-Pro-Arg-Pro-Gly-Pro, written TKPRPGP in one-letter notation. Its structure consists of the immunomodulatory tetrapeptide tuftsin, Thr-Lys-Pro-Arg, extended at the carboxyl terminus by a Pro-Gly-Pro segment. The molecular formula is commonly given as C33H57N11O9, corresponding to a monoisotopic mass near 751.4 Da and an average molecular mass near 751.9 Da. All seven residues are proteinogenic amino acids, and the molecule carries no modified side chains or non-natural linkages.
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.
Development took place at the Institute of Molecular Genetics of the Russian Academy of Sciences, where a series of short peptides were designed in the 1980s and 1990s. Selank was selected from variants of tuftsin that showed resistance to plasma peptidases. Russian regulatory approval covers it as an anxiolytic agent given intranasally. Outside that market the compound is normally handled as a research chemical rather than a medicine, and no widely recognised international pharmacopoeial monograph exists. The name Selank is a coined trade designation rather than a systematic chemical name.
Enzymatic stability motivates the extra three residues at the carboxyl end. Native tuftsin is cleaved quickly by circulating aminopeptidases and carboxypeptidases, which limits its duration of action and its usefulness as a tool compound. Extending the chain with proline-rich segments is a common design tactic because proline constrains the backbone and slows proteolysis. The same Pro-Gly-Pro motif appears in other Russian-developed peptides of the era. Whether the full seven-residue chain is required for activity, or whether it acts mainly as a prodrug releasing tuftsin, remains unresolved.
Selank is a synthetic heptapeptide with the sequence Thr-Lys-Pro-Arg-Pro-Gly-Pro. Its four N-terminal residues reproduce tuftsin, a tetrapeptide fragment of the immunoglobulin heavy chain, while the C-terminal Pro-Gly-Pro extension is a synthetic addition. The peptide has a molecular mass near 752 daltons and carries a net positive charge at physiological pH because of the arginine and lysine side chains. Published indexes list it under the name Selank and the sequence abbreviation TKPRPGP. Solid-phase peptide synthesis is the standard production route for research quantities.
The US Navy has actively participated in the Saudi-led naval blockade of Houthi-controlled territory in Yemen, which humanitarian organizations argue has been the main contributing factor to the outbreak of famine in Yemen. The four-month long Battle of Aden (2015) occurred between 25 March 2015 and 22 July. According to a 2015 September report by Esquire magazine, the Houthis, once the outliers, are now one of the most stable and organised social and political movements in Yemen. The power vacuum created by Yemen's uncertain transitional period has drawn more supporters to the Houthis. Many of the formerly powerful parties, now disorganised with an unclear vision, have fallen out of favour with the public, making the Houthis—under their newly branded Ansar Allah name—all the more attractive. Houthi spokesperson Mohamed Abdel Salam stated that his group had spotted messages between the UAE and Saleh three months before his death. He told Al-Jazeera that there was communication between Saleh, UAE and a number of other countries such as Russia and Jordan through encrypted messages. The alliance between Saleh and the Houthi broke down in late 2017, with armed clashes occurring in Sanaa from 28 November. Saleh declared the split in a televised statement on 2 December, calling on his supporters to take back the country and expressed openness to a dialogue with the Saudi-led coalition. On 4 December 2017, Saleh's house in Sanaa was assaulted by fighters of the Houthi movement, according to residents. Saleh was killed by the Houthis on the same day.
== Diagnosis == Detection of APCA (anti-parietal cell antibodies), anti-intrinsic factor antibodies (AIFA), and Helicobacter pylori (HP) antibodies in conjunction with serum gastrin are effective for diagnostic purposes.
=== Hurdles === Given the uneven distribution of vaccines across jurisdictions, granting privileges based on vaccination status certification means that those with easier vaccine access have unfair access to those privileges. If vaccination status is only verifiable using digital technology, those without that technology may also lose access even if they are vaccinated. Such privileging mechanisms may exacerbate inequality, increase risks of deliberate infections or transmission, Public health justifications for restricting behavior based on vaccine status have become less frequent over the course of the pandemic as vaccines do not stop transmission.
The hexagonal lattice structure of isolated, single-layer graphene can be directly seen with transmission electron microscopy (TEM) of sheets of graphene suspended between bars of a metallic grid. Some of these images showed a "rippling" of the flat sheet, with an amplitude of about one nanometer. These ripples may be intrinsic to the material as a result of the instability of two-dimensional crystals, or may originate from the ubiquitous dirt seen in all TEM images of graphene. Photoresist residue, which must be removed to obtain atomic-resolution images, may be the "adsorbates" observed in TEM images, and may explain the observed rippling. The hexagonal structure is also seen in scanning tunneling microscope (STM) images of graphene supported on silicon dioxide substrates The rippling seen in these images is caused by the conformation of graphene to the substrates' lattice and is not intrinsic.
== Inherited thrombocytopenia with normal MPV == ATRUS Syndrome Thrombocytopenia 2 (THC2) Congenital amegakaryocytic thrombocytopenia TAR syndrome Familial platelet disorder with predisposition to AML
Sources: en.wikipedia.org
==== Using detrital zircon age abundance ==== In a global scale, detrital zircon age abundance can be used as a tool to infer significant tectonic events in the past. In Earth's history, the abundance of magmatic age peaks during periods of supercontinent assembly. This is because supercontinent provides a major crustal envelop selectively preserve the felsic magmatic rocks, resulting from partial melts. Thus, many detrital zircons originate from these igneous provence, resulting similar age peak records. For instance, the peak at about 0.6–0.7 Ga and 2.7 Ga (Figure 6) may correlate the break-up of Rodinia and supercontinent Kenorland respectively.
The two substrates of this enzyme are L-serine and oxidised nicotinamide adenine dinucleotide phosphate (NADP+). Its products are L-3-oxo-alanine, reduced NADPH, and a proton. This enzyme belongs to the family of oxidoreductases, specifically those acting on the CH-OH group of donor with NAD+ or NADP+ as acceptor. The systematic name of this enzyme class is L-serine:NADP+ 3-oxidoreductase.
Genetically modified crops are genetically modified plants that are used in agriculture. The first crops developed were used for animal or human food and provide resistance to certain pests, diseases, environmental conditions, spoilage or chemical treatments (e.g. resistance to a herbicide). The second generation of crops aimed to improve the quality, often by altering the nutrient profile. Third generation genetically modified crops could be used for non-food purposes, including the production of pharmaceutical agents, biofuels, and other industrially useful goods, as well as for bioremediation.
== Food and Drug Administration == The FDA has minimal control when regulating dietary supplements like pre-workout. Product manufacturers are responsible to verify that dietary supplements are safe for consumption. Financial limitations prevent the FDA from testing dietary supplements before they enter the marketplace. Once a supplement is available for sale, the FDA is responsible to document and monitor manufacturer reports of adverse effects. Manufacturers are obligated to report documented adverse effects to the FDA. The FDA recommends speaking with a healthcare professional before using dietary supplements. Ingredients in pre-workout can have negative side effects or contraindications with other medications. Taking dietary supplements may have life-threatening consequences if taken with pre-existing health conditions. Federal laws state that a supplement does not have to be declared safe by FDA standards when labeled. Most supplement businesses hire third-party companies to identify the contents of their supplement to ensure it enhances athletic performance. This also aids in assuring that a product's labeled ingredients are free from illegal substances.
Sources: en.wikipedia.org
Many acupuncturists have argued that dry needling appears to be an acupuncture technique requiring minimal training that has been re-branded under a new name (dry needling). Whether dry needling is considered to be acupuncture depends on the definition of acupuncture, and it is argued that trigger points do not correspond to acupuncture points or meridians. They correspond by definition to the ad hoc category of 'a-shi' acupoints. This category of points is not necessarily distinct from other formal categories of acupoints. In 1983, Janet Travell described trigger point locations as 92% in correspondence with known acupuncture points. In 2006, a journal article concluded that the two point systems are in over 90% agreement. In 2009, Dorsher and Fleckenstein conclude that the strong (up to 91%) consistency of the distributions of trigger point regions' referred pain patterns to acupuncture meridians provides evidence that trigger points most likely represent the same physiological phenomenon as acupuncture points in the treatment of pain disorders. A comparison of Western trigger points to traditional acupuncture points corroborates the 92% correspondence. In 2011, The Council of Colleges of Acupuncture and Oriental Medicine published a position paper describing dry needling as an acupuncture technique. According to a qualitative review, dry needling combined with acupuncture was more effective in alleviating pain and achieved a higher response rate than dry needling alone.
=== Spectroscopy === In chemistry, spectroscopy is used to analyze products of reactions. To understand if dexamethasone is synthesized from a reaction, spectroscopy must be taken and compared to the literature spectrum. There are multiple spectroscopy analyses that can be taken including 1H NMR, 13C NMR, IR, Mass spectrometry, and UV/vis spectroscopy. Using IR spectroscopy, the peaks show the functional groups found in the molecule. Peaks at 3472, 1662, and 1618 represent alcohol, aldehyde, and alkene functional groups. UV-vis spectroscopy is another way to analyze a product to figure out what it is. Finally, mass spectroscopy showed peaks at: 393.1, 355.2 147.1 m/z. The peak at 393.1 m/z is the peak for dexamethasone as its molecular weight is 392.46 m/z.
ambassador to Israel Matt Gonzalez (1987), Green Party San Francisco mayoral candidate and independent 2008 candidate for vice president running with Ralph Nader Tim Kelly (1989), 74th mayor of Chattanooga, Tennessee Julie Menin (1989), former chairperson of Manhattan Community Board 1 and former commissioner of the New York City Department of Consumer Affairs Dave Hunt (1990), 65th speaker of the Oregon House of Representatives and majority leader 2007–2009 Michael Leiter (1991), principal deputy director of the National Counterterrorism Center; former deputy chief of staff for the Office of the Director of National Intelligence Melissa Mark-Viverito (1991), speaker of the New York City Council Benjamin Lawsky (1992), attorney and New York City's first superintendent of financial services Peter Hatch (1992), commissioner of the New York City Department of Consumer and Worker Protection Eric Garcetti (1992), member of the Los Angeles City Council and current mayor of Los Angeles, nominee to be U.S. ambassador to India Rohit Aggarwala (1993), commissioner of the New York City Department of Environmental Protection Matt Brown (1993), secretary of state of Rhode Island 2003–2007; co-founder of non-partisan group Global Zero Alan D.
=== Antiglobulin testing === The main method of antibody and antigen detection used in a clinical laboratory is red blood cell agglutination. Most IgM antibodies are easier to detect because they are larger and react at room temperature (20°C). This concept is what makes ABO/Rh testing so quick and easy to perform. However, most clinically significant non-ABO antibodies react at body temperature (37°C) and will not result in agglutination without the addition of multiple steps: incubation, washing, and the addition of anti-human globulin (AHG) reagent. Anti-human globulin is an antibody directed against human IgG antibodies. When the smaller IgG antibody is attached to red blood cells, the larger AHG antibodies create a cross-link between IgG sensitized RBC forming visual agglutination. When this agglutination is observed, the antiglobulin test is considered positive for the detection of the antibody and/or antigen(s) present. There are two main types of antiglobulin testing: indirect and direct. Indirect antiglobulin testing is used to detect antibodies in plasma/serum, whereas direct antiglobulin testing is used to detect antibody bound to red blood cells. When the direct antiglobulin test is positive, we must perform an antibody elution to remove the antibody for identification and to determine the antibody's clinical significance.
== Degradation == A peptide bond can be broken by hydrolysis (the addition of water). The hydrolysis of peptide bonds in water releases 8–16 kJ/mol (2–4 kcal/mol) of Gibbs energy. This process is extremely slow, with the half life at 25 °C of between 350 and 600 years per bond. In living organisms, the process is normally catalyzed by enzymes known as peptidases or proteases, although there are reports of peptide bond hydrolysis caused by conformational strain as the peptide/protein folds into the native structure. This non-enzymatic process is thus not accelerated by transition state stabilization, but rather by ground-state destabilization.
Sources: en.wikipedia.org
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.
Reported human trials are few, brief and originate mainly from one country. They describe effects on anxiety-related measures, but sample sizes are small and reporting is limited. The results are widely regarded as preliminary rather than confirmed.
Reverse-phase liquid chromatography is used to assess purity and separation of related impurities. Mass spectrometry confirms that the observed molecular mass matches the expected peptide. A certificate of analysis from the supplier is the usual document of record.
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.