Everything below concerns GABA-A receptor. We keep the language plain, cite what the science says, and separate well-supported claims from open questions.
Updated 2026-04-07. Numbers and descriptions here follow the published literature rather than marketing material.
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.
Reported activity for Selank centers on anxiolytic and nootropic effects. Russian clinical reports describe use in anxiety and in cognitive or attention-related complaints. Most of this evidence comes from studies conducted by the same research groups that developed the peptide. Independent replication in other countries remains limited, and no major Western regulatory agency has approved the compound for any indication. The gap between local reports and external verification is a recurring point in discussions of the peptide.
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.
| Property | Value | Notes |
|---|---|---|
| Peptide sequence | Thr-Lys-Pro-Arg-Pro-Gly-Pro | Seven residues; tuftsin plus a Pro-Gly-Pro tail |
| Molecular formula | C33H57N11O9 | Commonly reported value for the free peptide |
| Monoisotopic mass | Roughly 751.4 Da | Average molecular mass near 751.9 Da |
| Appearance | White to off-white powder | Typically supplied as a lyophilized solid |
| Solubility class | Freely soluble in water | Also dissolves in saline and other polar solvents |
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.
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.
Clinical evidence comes mainly from small studies conducted in Russia, several of which were open-label or lacked robust blinding. Reported outcomes include lower anxiety scores, changes in attention measures, and effects on asthenic states following illness. Sample sizes are typically in the tens of participants, and independent replication outside the region is scarce. Reviews published in English generally note the limited methodological quality of the underlying trials. Whether the compound produces clinically meaningful effects under rigorous conditions remains unresolved.
Proposed mechanisms center on modulation of the GABA system, but no single molecular target has been confirmed. Rodent studies report changes in GABA-A receptor expression and in the turnover of serotonin, dopamine, and norepinephrine in several brain regions. Increases in brain-derived neurotrophic factor and its receptor have also been described after repeated administration. These findings come largely from animal models, and the degree to which they describe human neurochemistry remains an open question. The mechanism is best characterized as multi-system and not fully resolved.
Pharmacokinetic data are limited. Like most short peptides, Selank is vulnerable to plasma and tissue peptidases, and its measured half-life in circulation is short, on a minutes scale. The Pro-Gly-Pro tail slows this degradation but does not eliminate it. Intranasal administration is the route described in most reports, with absorption through the nasal mucosa and a hypothesized path into the central nervous system that avoids the blood-brain barrier. Direct measurements of human brain exposure are unavailable, so distribution claims rest on inference from animal work.
Lyophilized Selank, the dry powder form, is generally stored frozen at minus 20 degrees Celsius or colder for long-term keeping. The solid is hygroscopic and should stay sealed, dry, and protected from light. Once dissolved, the peptide is less stable and is usually held refrigerated at 2 to 8 degrees Celsius for short periods. Repeated freezing and thawing is avoided because it can promote aggregation and loss of activity. Buffers and pH choice also affect how long a solution remains usable.
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.
=== Development and rationale === The TOPS System was developed in the early 2000s, with the concept of facet joint replacement introduced by biomedical engineer Uri Arnin. The idea was based on clinical observations that many patients undergoing lumbar spinal fusion have preserved intervertebral discs with degenerative spine pathology affecting the posterior elements of the vertebrae, including spinal stenosis, spondylolisthesis, and facet arthrosis. This led to the development of a motion-preserving alternative to fusion designed to maintain spinal stability following decompression. The first clinical implantations were performed in 2005, followed by international clinical use and subsequent randomized controlled trials comparing the device with fusion.
== Clinical relevance == In the metabolic disorder combined malonic and methylmalonic aciduria (CMAMMA), the mitochondrial enzyme ACSF3 is defective, which contributes to the mitochondrial malonyl-CoA pool by converting malonate. The reduced availability of the donor malonyl-CoA leads to a decrease in mitochondrial lysine malonylation. In mouse models, this hypomalonylation has been shown to disrupt key metabolic pathways such as glycolysis, gluconeogenesis, fatty acid oxidation and NADPH metabolism, ultimately impairing energy balance. In the metabolic disorder malonic aciduria, the enzyme malonyl-CoA decarboxylase (MCD) is defective, required for the conversion of malonyl-CoA to acetyl-CoA. This leads to accumulation of malonyl-CoA and a marked increase in lysine malonylation. Proteomic and functional analyses have shown that this hypermalonylation impairs mitochondrial respiration and reduces fatty acid oxidation capacity, suggesting a direct role for protein malonylation in the disease's metabolic dysfunction. Clinical similarities between MCD and ACSF3 defects suggest their involvement in a shared pathway. Malonylation also occurs on nuclear proteins, including histones, where it regulates chromatin-associated processes. Histone malonylation has been shown to increase ribosomal RNA (rRNA) expression and nucleolar size, both of which are features associated with cellular aging.
costmary, 1–66 grams sweet flag, 20 grams hypericum, 8 grams Natural gum, 8 grams sagapenum, 8 grams acacia juice, 8 grams Illyrian iris (probably I. germanica), 8 grams cardamom, 8 grams anise, 12 grams Gallic nard (Valeriana italica), 16 grams gentian root, 16 grams dried rose leaves, 16 grams poppy-tears (Papaver rhoeas, a wild poppy with low opiate content), 17 grams parsley, 17 grams cassia, 20–66 grams saxifrage, 20–66 grams darnel, 20–66 grams long pepper, 20–66 grams storax, 21 grams castoreum, 24 grams frankincense, 24 grams hypocistis juice, 24 grams myrrh, 24 grams opopanax, 24 grams malabathrum leaves, 24 grams flower of round rush, 24–66 grams turpentine-resin, 24–66 grams galbanum, 24–66 grams Cretan carrot seeds, 24–66 grams nard, 25 grams opobalsam, 25 grams shepherd's purse, 25 grams rhubarb root, 28 grams saffron, 29 grams ginger, 29 grams cinnamon, 29 grams The ingredients are then "pounded and taken up in honey. Against poisoning, a piece the size of an almond is given in wine. In other affections an amount corresponding in size to an Egyptian bean is sufficient." Of these ingredients, Illyrian iris, darnel, and rhubarb were not commonly found in other versions of the antidote. However, Celsus' formulation, written 100 years after the death of Mithridates, was one of the first published. Galen called the antidote "theriac" and presented versions by Aelius (used by Julius Caesar), Andromachus (physician to Nero), Antipater, Nicostratus, and Damocratis. The Andromachus formulation closely resembles that of Celsus.
N-Desethylfluornitrazene (DFNZ or D-FNZ) is an atypical opioid analgesic of the nitazene family related to etonitazene. It is the N-desethyl analogue of fluornitazene (FNZ). DFNZ is the major active metabolite of FNZ, which appears to act as a prodrug of DFNZ. The drug is a highly selective superagonist of the μ-opioid receptor (MOR), with an affinity (Ki) of 1.0 nM, an EC50Tooltip half-maximal effective concentration of 1.66 to 8.49 nM, and an EmaxTooltip maximal efficacy of 104 to 119%. It shows some biased agonism at the MOR, preferring G protein to β-arrestin signaling. DFNZ shows a unique spatiotemporal pattern of MOR activation in vivo. It exhibits central permeability, but has impaired brain penetrance and thus some peripheral selectivity. The drug is a substrate of both P-glycoprotein and breast cancer resistance protein (BCRP), in contrast to FNZ, and this is responsible for its reduced capacity to cross the blood–brain barrier. Due to its peripheral selectivity, it shows limited MOR occupancy in the brain in rodents. DFNZ produces strong analgesic effects in rodents. It also produces antiallodynic effects, induces hyperlocomotion, and substitutes for heroin, thereby reducing heroin self-administration. Conversely, the drug does not produce respiratory depression, does not cause brain hypoxia at analgesic doses, does not downregulate the MOR, produces little or no tolerance and withdrawal, and shows weak reinforcing effects in rodents.
Sources: en.wikipedia.org
== Most complicated pocket watches == The Vacheron Constantin Reference 57260 (2015) – 57 complications Patek Philippe Calibre 89 (1989) – 33 complications Patek Philippe Henry Graves Supercomplication (1933) – 24 complications
=== Non-selective peptide toxins === ω-Grammotoxin SIA is a peptide toxin derived from the venom of the spider Grammostola spatulata. It acts to modify the P-type channel gating. ω-PnTx3-3, PnTx3-3, and phonetoxin IIA are all toxins from the spider Phonoetrica nigriventer which act to block the current through the P-type calcium channels. DW13.3 is a peptide toxin from the spider Filistata hibernalis and it is composed of 74 amino acids. It also functions to block the current through P-type calcium channels. ω-Conotoxins are derived from the venom of cone snails. ω-Conotoxin MVIIC acts within the hippocampal CA1 pyramidal neurons to block the P-type channels. Also, within the hippocampal CA3 neurons, this toxin blocks synaptic transmission. Its effects are slow. Calcicludine is from venom of Dendroaspis angusticeps, which is a green mamba. It has the ability to voltage-dependently block P-type channels. Kurotoxin is from venom of the scorpion Parabuthus. In neurons in the thalamus, kurtoxin decreases high threshold calcium currents, however, in the Purkinje cells, it increases the calcium currents.
From 2024, Powys would be in the UK parliament constituencies of Brecon, Radnor and Cwm Tawe and Montgomeryshire and Glyndŵr, both of which extend out of the county. From 2026, it would be part of the two Senedd constituencies of Brycheiniog Tawe Nedd and Gwynedd Maldwyn.
== History == The president was only the head of state under previous constitutions but under current constitution, it is both the head of state and head of government. The position of president as a head of state was created in 1948, with the adoption of the Burmese Declaration of Independence from the United Kingdom. Since then, eleven people have officially held the office. The office of the president was abolished twice when direct military rule was imposed by the coups of 1962 and 1988. In the parliamentary system practised in 1948–1962, the "President" was the ceremonial head of state while prime minister is the actual head of government. The first president of 1948–1952 period was titled "Provisional President" because he had been elected by the Constituent Assembly of Burma, not by the Union Parliament. The first "President" elected by the Union Parliament took office in 1952. The 1962 coup d'etat abolished both offices of the President and the Prime Minister, and the junta leader assumed the powers of both head of state and head of government as the "Chairman" of "Revolutionary Council" and "Revolutionary Government". The 1974 Constitution reintroduced the office with the title "President of the Republic", to be ex officio held by the "Chairman of the Council of State". In fact, the chairmanship of the Council of State is the main title of the head of state which was used in promulgation of legislations and orders while the presidency is more like a ceremonial title to represent the country.
The thorax is robust and bears three pairs of legs and one pair of wings. The wings are clear and membranous, with fine veins visible, and span approximately 4 mm. They are held flat over the back when the fly is at rest. Just behind the wings are small knob-like structures called halteres, which are modified hindwings. These help the fly maintain balance and orientation in flight. The drosophila leg is composed of five leg segments: the coxa, trochanter, femur, tibia, and tarsus. They have five tarsal segments in their tarsus, ending with the fly foot which has multiple structures including the claw and adhesive structures. The pulvillus, a flexible elongated structure underneath the claw, and setae, hair-like structures that are spatula-shaped and inset the pulvilli, are the main attachment devices used by D. melanogaster, although their claws may be used for attachment onto rough surfaces. Males also have sex combs located on the first tarsal segment, which are tiny bristle-like structures on their front legs, used to attach to females during mating. Extensive images are found at FlyBase. The abdomen is segmented and tapers toward the end. It often appears striped, with alternating bands of light and dark pigmentation. In males, the abdomen is typically darker and more rounded, while females have a more pointed and striped abdomen. The black portions of the abdomen are the inspiration for the species name (melanogaster = "black-bellied"). They exhibit sexual dimorphism; females are about 2.5 mm (0.10 in) long, while males are slightly smaller.
Sources: en.wikipedia.org
Both the pharmaceutical supply chain and the illicit supply chain obtain cocaine from coca cultivated in Latin America, but they operate under very different controls and oversight. In Peru, for example, legal coca cultivation is monopolized by the state company National Coca Company (ENACO), yet approximately 90% of coca leaves produced in the country are diverted to illegal actors for cocaine manufacturing. As a result, these illicit coca crops are a primary target of ongoing government-led coca eradication efforts. Cocaine is prohibited in competition for athletes by the World Anti-Doping Agency (WADA), which lists it as a stimulant on its International Standard for the Prohibited List.
PEAKS and NovoHMM had the best sensitivity in both QSTAR and LCQ data as well. However, no evaluated algorithms exceeded a 50% of exact identification for both data sets. Recent progress in mass spectrometers made it possible to generate mass spectra of ultra-high resolution [1]. The improved accuracy, together with the increased amount of mass spectrometry data that are being generated, draws the interests of applying deep learning techniques to de novo peptide sequencing. In 2017 Tran et al. proposed DeepNovo, the first deep learning based de novo sequencing software. The benchmark analysis in the original publication demonstrated that DeepNovo outperformed previous methods, including PEAKS, Novor and PepNovo, by a significant margin. DeepNovo is implemented in python with the Tensorflow framework. To represent a mass spectrum as a fixed-dimensional input to the neural-network, DeepNovo discretized each spectrum into a length 150,000 vector. This unnecessarily large spectrum representation, and the single-thread CPU usage in the original implementation, prevents DeepNovo from performing peptide sequencing in real time. To further improve efficiency of de novo peptide sequencing models, Qiao et al. proposed PointNovo in 2020. PointNovo is a python software implemented with the PyTorch framework and it gets rid of the space consuming spectrum-vector-representation adopted by DeepNovo. Comparing with DeepNovo, PointNovo managed to achieve better accuracy and efficiency at the same time by directly representing a spectrum as a set of m/z and intensity pairs.
Modern food distribution in the United States is a result of continued growth since the 1960s. In an increasingly connected world, food distribution efforts in the US reach from coast to coast. A network of infrastructure, warehouses, factories, and commercial retailers comprise the bulk of US food distribution. It is estimated that food served in the United States may travel close to 1,500 miles between growers and consumers. While many products, specifically meat and grain, are distributed in different fashions, there are common trends to the distribution of most modern foods. An increase in the use of technology for farming has transformed the small local farm of the 1940s in to large production facilities. Several federal agencies, such as the US Department of Agriculture and the Food and Drug Administration, manage and sustain the productivity of the US food distribution system.
== Enthalpy change == The enthalpy of sublimation has commonly been predicted using the equipartition theorem. If the lattice energy is assumed to be approximately half the packing energy, then the following thermodynamic corrections can be applied to predict the enthalpy of sublimation. Assuming a 1 molar ideal gas gives a correction for the thermodynamic environment (pressure and volume) in which pV = RT, hence a correction of 1RT. Additional corrections for the vibrations, rotations and translation then need to be applied. From the equipartition theorem gaseous rotation and translation contribute 1.5RT each to the final state, therefore a +3RT correction. Crystalline vibrations and rotations contribute 3RT each to the initial state, hence −6RT. Summing the RT corrections; −6RT + 3RT + RT = −2RT. This leads to the following approximate sublimation enthalpy. A similar approximation can be found for the entropy term if rigid bodies are assumed.
N-Desalkylflurazepam (also known as norflurazepam) is a benzodiazepine analog and an active metabolite of several other benzodiazepine drugs including flurazepam, flutoprazepam, fludiazepam, midazolam, flutazolam, quazepam, and ethyl loflazepate. It is long-acting, prone to accumulation, and binds unselectively to the various benzodiazepine receptor subtypes. It has been sold as a designer drug from 2016 onward.
Sources: en.wikipedia.org
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.
No peptide with this exact sequence has been identified as an endogenous substance. It is a laboratory-designed analog of tuftsin, a naturally occurring immunomodulatory tetrapeptide. The Pro-Gly-Pro extension has no known natural source.
Proline introduces conformational constraints that make a peptide less accessible to common peptidases. This is a standard stabilization strategy in peptide design. The added residues also increase the distance between the active tuftsin portion and typical cleavage sites.
Selank is a synthetic peptide made of seven amino acids. It is modeled on tuftsin, a natural tetrapeptide, with an added three-residue tail. It is not a small-molecule drug.