This is a working overview of Certificate of analysis, written for readers who want more than a one-paragraph summary but less than a textbook.
Reviewed 2026-05-09. Anything still debated is marked as such rather than presented as settled.
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.
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.
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.
The compound was designed at the Institute of Molecular Genetics of the Russian Academy of Sciences during the 1980s and 1990s. The stated design goal was to retain the immunomodulatory and central nervous system activity attributed to tuftsin while improving resistance to enzymatic breakdown. Adding a proline-rich tail to the short parent peptide was a deliberate strategy, because proline residues restrict the conformations available to many peptidases. The same laboratory produced Semax, an ACTH fragment analog, and both compounds were developed in parallel as short, enzymatically stabilized peptides intended for intranasal use.
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.
| 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 |
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.
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.
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.
Lyophilised material kept dry at minus 20 degrees Celsius or colder is the most stable form, and suppliers commonly state a shelf life of two years or more under those conditions. Once dissolved, degradation accelerates through hydrolysis and deamidation, particularly at alkaline pH or elevated temperature. Working solutions are usually divided into single-use aliquots to avoid repeated freeze-thaw cycles. The choice of reconstitution solvent affects both stability and the ionic strength of the final preparation.
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.
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.
Development work on the compound began in the 1980s and 1990s at the Institute of Molecular Genetics in Moscow, within the same research programme that produced the peptide Semax. Early investigators sought a tuftsin derivative with improved resistance to enzymatic breakdown and with activity in the central nervous system after peripheral administration. Most of the primary literature from this period was published in Russian, a factor that still shapes how easily the findings can be checked by outside groups.
Although, according to the Alcohol and Tobacco Tax and Trade Bureau (TTB) cider producers can only label a product 'Ice Cider' if it is produced from apples naturally frozen outdoors. Two styles not mentioned in the USACM Cider Style Guide are Rosé and Sparkling Cider. Rosé cider can be produced from apple varieties that have reddish-pink pulp, like Pink Pearl and Amour Rouge. Rosé ciders can also be created through the addition of food-grade red dyes, previously used red grape skins, like Marquette with high anthocyanin concentration, red fruits, rose petals, or hibiscus. Lastly, sparkling ciders can be produced through methods of direct carbonation, addition of carbon dioxide (CO2) or by Méthode Champenoise to re-create the traditional Champagne style.
The latter programme took place in Vichy, and was spread over three weeks, allowing Wenger to be able to put Frantz's teachings of isometrics into practice. In 1981, he received his manager's diploma in Paris.
Serbs = 6,331,527 (67.96%) Albanians = 1,303,032 (13.99%) Yugoslavs = 441,941 (4.75%) Hungarians = 390,468 (4.19%) Muslims = 215,166 (2.31%) Croats = 149,368 (1.60%) Romani = 110,956 (1.19%) Macedonians = 48,986 (0.53%) Slovenes = 12,006 (0.13%)
Sources: en.wikipedia.org
Portugal has a predominantly universal tax-funded health care system, called Serviço Nacional de Saúde (SNS), that operates alongside public-sector health insurance schemes called health subsystems funded mainly through employee and employer contributions, as well as private voluntary health insurance. Primary and hospital care are provided by both public and private entities, with the private sector and complementing services offered by the SNS. In 2023, Portugal had the 3rd lowest public share on health spending in the European Union and over half of public hospitals in technical insolvency in 2020. Portugal has a high level of health inequity in the OECD, driven by limited public spending, uneven distribution of services, low household income, long waiting times, and policy shortcomings. Portugal ranked 23rd in the world in 2024 in life expectancy with 85.4 years for women and 79.8 years for men, and it had an infant mortality rate of 2.7 deaths per 1,000 live births. In 2022, the leading cause of death were cardiovascular diseases, at 25.4%. Portugal presents several adverse public-health indicators, including the 3rd lowest share of people reporting good health in the European Union, in 2024, at 54%, the highest alcohol consumption with 11.9 litres (2.6 imp gal; 3.1 US gal) consumed per person, in 2020, and the highest share of adult population living a sedentary lifestyle, in 2022, at 73%, a pattern reinforced by limited active-transport infrastructure and unsafe conditions for pedestrians and cyclists.
=== Evolution and biogeography === The development of a phylogenetic approach to taxonomy suggested the Liliales formed some of the earliest monocots. Molecular analysis indicates that divergence amongst the Liliales probably occurred around 82 million years ago. The closest sister family to the Liliaceae are the Smilacaceae, with the Liliaceae separating 52 million years ago. Liliaceae thus arose during the Late Cretaceous to Early Paleogene periods. Major evolutionary clades include the Lilieae (Lilium, Fritillaria, Nomocharis, Cardiocrinum, Notholirion) from the Himalayas about 12 mya and the Tulipeae (Erythronium, Tulipa, Gagea) from East Asia at about the same time. The Medeoleae (Clintonia and Medeola) may have appeared in North America but were subsequently dispersed, as may have the Streptopoideae and Calochortoideae. Liliaceae fossils have been dated to the Paleogene and Cretaceous eras in the Antarctic. The Liliaceae probably arose as shade plants, with subsequent evolution to open areas including deciduous forest in the more open autumnal period, but then a return of some species (e.g. Cardiocrinum). This was accompanied by a shift from rhizomes to bulbs, to more showy flowers, the production of capsular fruit and narrower parallel-veined leaves. Again, some reversal to the broader reticulate-veined leaves occurred (e.g. Cardiocrinum).
expression vector Also expression construct. A type of vector, usually a plasmid or viral vector, designed specifically for the expression of a transgene insert in a target cell, rather than for some other purpose such as cloning.
Hypotonia (floppiness) Developmental delay Oculogyric crises Difficulty with initiating and controlling movements Dystonia and dyskinesia Gastointestinal dysmotility which can present at as vomiting, gastro-oesophageal reflux, diarrhoea and/or constipation Autonomic symptoms including difficulties controlling temperature and blood sugar, excessive sweating and nasal congestion Some people may develop cerebral folate deficiency, because O-methylation of the excessive amounts of L-DOPA can deplete methyl donors such as S-adenosyl methionine and levomefolic acid. This deviation can be detected by measuring the levels of levomefolic acid in the cerebrospinal fluid, and can be corrected by folinic acid.
Sources: en.wikipedia.org
===== Temperature ===== Temperature has a multiplicity of effects on plants depending on a variety of factors, including the size and condition of the plant and the temperature and duration of exposure. The smaller and more succulent the plant, the greater the susceptibility to damage or death from temperatures that are too high or too low. Temperature affects the rate of biochemical and physiological processes, rates generally (within limits) increasing with temperature. However, the Van't Hoff relationship for monomolecular reactions (which states that the velocity of a reaction is doubled or trebled by a temperature increase of 10 °C) does not strictly hold for biological processes, especially at low and high temperatures. When water freezes in plants, the consequences for the plant depend very much on whether the freezing occurs intracellularly (within cells) or outside cells in intercellular (extracellular) spaces. Intracellular freezing usually kills the cell regardless of the hardiness of the plant and its tissues. Intracellular freezing seldom occurs in nature, but moderate rates of decrease in temperature, e.g., 1 °C to 6 °C/hour, cause intercellular ice to form, and this "extraorgan ice" may or may not be lethal, depending on the hardiness of the tissue. At freezing temperatures, water in the intercellular spaces of plant tissues freezes first, though the water may remain unfrozen until temperatures fall below 7 °C. After the initial formation of ice intercellularly, the cells shrink as water is lost to the segregated ice.
=== Transmitter === The transmitter is the component of the Dexcom CGM system that is responsible for sending glucose data from the sensor to a compatible receiver, smartphone, or other monitoring device via Bluetooth, allowing users to view real-time glucose readings. Throughout previous iterations of the Dexcom CGM, the transmitter has typically been shaped like a pear. The Dexcom G7 and Stelo models feature a smaller, rounder design and integrate the sensor and transmitter into a single, disposable system.
=== Original BCA assay === As described by Smith, the original BCA assay is a two-component protocol. The two reagents are "stable indefinitely at room temperature". Modern (likely exact or highly similar) formulations are available from at least two commercial vendors. The BCA Working solution is generated by mixing Reagent A and Reagent B in a 50:1 ratio, and can be prepared either weekly (it is moderately stable), or as needed. Reagent A
In March 1917, the abdication of Tsar Nicholas II led to the Russian Provisional Government (March–July 1917), who then proclaimed the Russian Republic (September–November 1917). Later in the October Revolution, the Bolshevik's seizure of power against the Provisional Government resulted in their establishment of the Russian Soviet Federative Socialist Republic (1917–1991), yet parts of Russia remained occupied by the counter-revolutionary White Movement of anti-communists who had united to form the White Army to fight the Russian Civil War (1917–1922) against the Bolshevik government. Moreover, despite the White–Red civil war, Russia remained a combatant in the Great War that the Bolsheviks had quit with the Treaty of Brest-Litovsk which then provoked the Allied Intervention to the Russian Civil War by the armies of seventeen countries, featuring Great Britain, France, Italy, the United States and Imperial Japan.
Changes in the levels of oxygen, carbon dioxide, and plasma pH are sent to the respiratory center, in the brainstem where they are regulated. The partial pressure of oxygen and carbon dioxide in the arterial blood is monitored by the peripheral chemoreceptors (PNS) in the carotid artery and aortic arch. A change in the partial pressure of carbon dioxide is detected as altered pH in the cerebrospinal fluid by central chemoreceptors (CNS) in the medulla oblongata of the brainstem. Information from these sets of sensors is sent to the respiratory center which activates the effector organs – the diaphragm and other muscles of respiration. An increased level of carbon dioxide in the blood, or a decreased level of oxygen, will result in a deeper breathing pattern and increased respiratory rate to bring the blood gases back to equilibrium. Too little carbon dioxide, and, to a lesser extent, too much oxygen in the blood can temporarily halt breathing, a condition known as apnea, which freedivers use to prolong the time they can stay underwater. The partial pressure of carbon dioxide is more of a deciding factor in the monitoring of pH. However, at high altitude (above 2500 m) the monitoring of the partial pressure of oxygen takes priority, and hyperventilation keeps the oxygen level constant. With the lower level of carbon dioxide, to keep the pH at 7.4 the kidneys secrete hydrogen ions into the blood and excrete bicarbonate into the urine. This is important in acclimatization to high altitude.
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.
The sequence is Thr-Lys-Pro-Arg-Pro-Gly-Pro, written TKPRPGP in one-letter code. It combines the tetrapeptide tuftsin with a carboxyl-terminal Pro-Gly-Pro extension. This full sequence identifies the molecule more precisely than the research name.