This is a working overview of nootropic, written for readers who want more than a one-paragraph summary but less than a textbook.
Reviewed 2025-11-14. Anything still debated is marked as such rather than presented as settled.
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.
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.
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.
| Property | Value | Notes |
|---|---|---|
| Primary route studied | Intranasal | Also examined parenterally in animal work |
| Reported plasma half-life | Minutes to tens of minutes | Values vary widely between reports |
| Main model systems | Rodent behavioural and cell assays | Human trials are few and small |
| Principal proposed targets | GABA-A receptor, GABA transaminase | Monoamine and neurotrophic pathways also reported |
| Evidence grade | Preliminary | Limited independent replication |
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.
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.
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.
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.
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.
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.
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.
=== EC 7.3 Catalysing the translocation of inorganic anions === This subclass contains translocases that transfer inorganic cations anions. Subclasses are based on the reaction processes that provide the driving force for the translocation. At present only one subclass is represented: EC 7.3.2 Translocation of inorganic anions linked to the hydrolysis of a nucleoside triphosphate.
After this, Agathocles of Syracuse ravaged the coast of Calabria with his fleet, took Hipponium and forced the Bruttii into unfavourable peace terms. However, they soon seized Hipponium again. After Agathloces' death in 289 BCE the Lucanians and Bruttii pushed into the territory of Thurii and ravaged it. The city sent envoys to Rome to ask for help in 285 and 282 BCE. On the second occasion, the Romans sent forces to garrison the city. This was part of the episode that sparked the Pyrrhic war. The name Italy entered common usage, defining the inhabitants of the city-states of the Mezzogiorno first as Italiotes, then Italics with the arrival of the Romans, who would later include Cisalpine Gaul.
=== REDEFINE 5 === In April 2026, results were published in The Lancet on REDEFINE 5, a 68-week, double-blind, phase 3a clinical trial enrolling 331 participants. The study findings report that participants in the CagriSema cohort had an estimated mean bodyweight change of -18.4%, versus -11.7% for participants in the semaglutide cohort.
Pictures, movies and applets showing the anatomy of Mus musculus, from www.digimorph.org Michael Purdy: "Researchers add mice to list of creatures that sing in the presence of mates" Archived 2008-12-26 at the Wayback Machine-Study of male mouse "song" with mouse song recording (MP3), by Washington University Medical School "It's just in mice! This scientist is calling out hype in science reporting". STAT. 2019-04-15. Arkive Photographs.Short text. High-Resolution Brain Maps and Brain Atlases of Mus musculus Further reading
=== Museums and galleries === A notable art museum in Moscow is the Tretyakov Gallery, which was founded by Pavel Tretyakov, a wealthy patron of the arts who donated a large private collection to the city. The Tretyakov Gallery is divided into two buildings. The Old Tretyakov Gallery—the original gallery in the Tretyakovskaya area on the south bank of the Moskva River—houses traditional Russian works. Art by pre-Revolutionary painters, such as Ilya Repin, as well as art by early Russian icon painters, is also displayed. In addition, the museum contains rare originals by early 15th-century iconographer Andrei Rublev. The New Tretyakov Gallery, created in Soviet times, contains primarily Soviet art, as well as a few contemporary paintings; however, the old and new buildings overlap for early 20th-century art. The new building includes a small reconstruction of Vladimir Tatlin's famous Monument to the Third International, as well as other avant-garde works by artists such as Kazimir Malevich and Wassily Kandinsky. Socialist realism also appears in the new building.
Sources: en.wikipedia.org
=== Environmental and health hazards === Synthetic phenolic antioxidants (SPAs) and aminic antioxidants have potential human and environmental health hazards. SPAs are common in indoor dust, small air particles, sediment, sewage, river water and wastewater. They are synthesized from phenolic compounds and include 2,6-di-tert-butyl-4-methylphenol (BHT), 2,6-di-tert-butyl-p-benzoquinone (BHT-Q), 2,4-di-tert-butyl-phenol (DBP) and 3-tert-butyl-4-hydroxyanisole (BHA). BHT can cause hepatotoxicity and damage to the endocrine system and may increase the carcinogenicity of 1,1-dimethylhydrazine exposure. BHT-Q can cause DNA damage and mismatches through the cleavage process, generating superoxide radicals. DBP is toxic to marine life if exposed long-term. Phenolic antioxidants have low biodegradability, but they do not have severe toxicity toward aquatic organisms at low concentrations. Another type of antioxidant, diphenylamine (DPA), is commonly used in the production of commercial, industrial lubricants and rubber products and it also acts as an additive for automotive engine oils.
The reaction of endo-Tropacocaine [19145-60-9] (1) with 2,2,2-Trichloroethyl chloroformate (Troc group) [17341-93-4] (2) gave the urethane PC11463908 (3). Reduction with zinc in acetic acid afforded the nortropane, PC11458897 (4). Protection of the secondary amine with Boc anhydride gave PC66624775 (5). Saponification of the ester in potassium hydroxide gave PC11160507 (6). Mitsunobu reaction with 7-hydroxy-3-methoxy-chromen-2-one (Methoxy-Umbelliferon) [68287-05-8] (7) occurred with inversion of stereochemistry from the endo to the exo position, PC89405050 (8). Acid hydrolysis of the Boc protecting group completed the synthesis of pudafensine (9).
==== COVID-19 pandemic ==== In response to the COVID-19 pandemic, most Church's Chicken restaurants closed their dining rooms and continued their drive-thru, counter, takeout and delivery services. In March 2020, company executives announced a franchisee relief plan, where Church's Chicken franchisees could defer 50% of their royalties and ad fund contributions for the next four weeks.
Germany is a federation comprising sixteen constituent states referred to as Länder, thirteen of which are so-called "area-states" (Flächenländer). Two states, Berlin and Hamburg, are city-states (Stadtstaaten), in which there is no separation between state government and local administration. The state of Bremen, though officially also called a Stadtstaat, consists of the cities of Bremen, for which the state government also serves as the municipal administration, and the exclave of Bremerhaven. Each state (Land) has its own constitution and is largely autonomous in its organisation. As of 2017, Germany is divided into 401 districts (Kreise) at a municipal level; these consist of 294 rural districts and 107 urban districts.
== Pharmacological effects == Calendula officinalis oil is still used medicinally as an anti-inflammatory and a remedy for healing wounds. Calendula ointments are skin products available for use on minor cuts, burns, and skin irritation; though evidence of their effectiveness is weak. Plant pharmacological studies have suggested that Calendula extracts have antiviral, antigenotoxic, and anti-inflammatory properties in vitro. In herbalism, Calendula in suspension or in tincture is used topically for treating acne, reducing inflammation, controlling bleeding, and soothing irritated tissue. Limited evidence indicates Calendula cream or ointment is effective in treating radiation dermatitis. Topical application of C. officinalis ointment has helped to prevent dermatitis and pain; thus reducing the incidence rate of skipped radiation treatments in randomized trials. Calendula has been used traditionally for abdominal cramps and constipation. In experiments with rabbit jejunum, the aqueous-ethanol extract of C. officinalis flowers was shown to have both spasmolytic and spasmogenic effects, thus providing a scientific rationale for this traditional use. An aqueous extract of C. officinalis obtained by a novel extraction method has demonstrated antitumor (cytotoxic) activity and immunomodulatory properties (lymphocyte activation) in vitro, as well as antitumor activity in mice. Calendula plants are known to cause allergic reactions in susceptible individuals, and should be avoided during pregnancy.
Sources: en.wikipedia.org
Hohhot Baita International Airport (IATA: HET, ICAO: ZBHH) is an international airport serving Hohhot, the capital of Inner Mongolia, China. It is the largest airport in Inner Mongolia and lies 14.3 km (8.9 mi) east of downtown Hohhot. Its name Baita, meaning White Pagoda, derives from Wanbu Huayanjing Pagoda; one of the historical attractions in Hohhot which lies 5.6 km (3.5 mi) south-east of the airport. In 2025 it served 12,722,692 passengers.
=== Use of ICT in general === Members of Generation Z have acquired a "digital bond to the Internet" from a very young age. According to the Pew Research Center, a defining feature of this cohort is that the majority owns a cell phone. About one quarter of teens are almost constantly online and 80% feel distressed if separated from their electronic gadgets. Generation Z spends on average six hours each day on the Internet, much of it playing video games. That much of Generation Z is growing up with constant access to Internet-enabled devices has undermined parental authority and control, prompting concerns over the sort of information children are exposed to while surfing the World Wide Web.
=== Differential diagnosis === Recognizing IPF in clinical practice can be challenging as symptoms often appear similar to those of more common diseases, such as asthma, chronic obstructive pulmonary disease (COPD) and congestive heart failure. The key issue facing clinicians is whether the presenting history, symptoms (or signs), radiology, and pulmonary function testing are collectively in keeping with the diagnosis of IPF or whether the findings are due to another process. It has long been recognized that patients with ILD related to asbestos exposure, drugs (such as chemotherapeutic agents or nitrofurantoin), rheumatoid arthritis and scleroderma/systemic sclerosis may be difficult to distinguish from IPF. Other differential diagnostic considerations include interstitial lung disease related to mixed connective tissue disease, advanced sarcoidosis, chronic hypersensitivity pneumonitis, pulmonary Langerhan's cell histiocytosis and radiation-induced lung injury.
== Mechanism == NADK phosphorylates NAD+ at the 2’ position of the ribose ring that carries the adenine moiety. It is highly selective for its substrates, NAD and ATP, and does not tolerate modifications either to the phosphoryl acceptor, NAD, or the pyridine moiety of the phosphoryl donor, ATP. NADK also uses metal ions to coordinate the ATP in the active site. In vitro studies with various divalent metal ions have shown that zinc and manganese are preferred over magnesium, while copper and nickel are not accepted by the enzyme at all. A proposed mechanism involves the 2' alcohol oxygen acting as a nucleophile to attack the gamma-phosphoryl of ATP, releasing ADP.
ELPs modified with certain functional groups have the capacity to be conjugated with drugs, including chemotherapeutic agents. Together, the ELP-drug complex can be taken up by tumor cells to a greater extent, promoting the cytotoxic activity of the drug. The reason that the complexes preferentially target the tumor cells is that these cells tend to be associated with more permeable blood vessels and also possess a weaker lymphatic presence. This essentially means that the drugs can cross over from the vessels to the tumor cells more frequently and can remain in the vessels for a longer period of time, without being filtered out. The phase transition associated with ELPs can also be used to promote tumor cell uptake of the drug. By locally heating tumor cell regions, the ELP-drug complex will aggregate into spherical clumps. If this ELP-drug complex is engineered to expose functional domains in the spherical clump shape that are recognized by tumor cell surfaces, then this cell surface interaction would promote uptake of the drug as the tumor cell would mistake the ELP-drug complex as being a harmless substance.
Sources: en.wikipedia.org
Reports describe modulation of GABA signalling, changes in monoamine turnover and effects on neurotrophic factor expression. These observations come mainly from animal and cell studies. A single unifying mechanism has not been demonstrated.
The peptide enters plasma rapidly and is broken down by ordinary proteases into amino acids and shorter fragments. Reported half-lives are short. Whether meaningful amounts of the intact molecule reach the brain is an open question.
Most clinical reports are small, published in Russian and not independently replicated. English-language reviews highlight the absence of large randomised trials. Conclusions about efficacy should be treated as provisional.
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.