Everything below concerns batch purity. We keep the language plain, cite what the science says, and separate well-supported claims from open questions.
Updated 2026-07-15. Numbers and descriptions here follow the published literature rather than marketing material.
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.
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.
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.
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.
| 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 |
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.
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.
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.
Purity assessment relies mainly on reverse-phase high-performance liquid chromatography with ultraviolet detection. Because the peptide lacks a strong chromophore, detection often uses backbone absorbance near 214 nm. Identity is confirmed by mass spectrometry, typically electrospray ionization or matrix-assisted laser desorption, comparing the measured mass against the expected value. Amino acid analysis can verify composition after acid hydrolysis. Diastereomer content and residual counterions are reported less often, although both can influence biological assays.
Lyophilized material is generally stable for extended periods when kept dry at or below minus twenty degrees Celsius. Working solutions are less stable, and common practice is to aliquot and freeze them so that repeated freeze-thaw cycles are avoided. Aqueous solutions are sensitive to pH extremes and to microbial growth, so short-term storage at refrigerator temperature is typical. Oxidation and hydrolysis are the principal degradation routes. Reconstitution with sterile water or a mild buffer is standard, and solutions should be protected from light.
The compound has a calculated molecular weight near 751.9 daltons and carries a net positive charge at physiological pH because of its arginine residue. It dissolves freely in water and in common aqueous buffers, and typically appears as a white or off-white lyophilized powder. The amide backbone makes the molecule susceptible to peptidases, which limits oral use and favors intranasal or parenteral routes. Nomenclature in the literature varies: the substance is also described by the sequence abbreviation TP-7 and by a Russian trade designation.
Regulatory status differs sharply by region. Selank holds a Russian marketing authorization, where it is supplied mainly as nasal drops, while authorities elsewhere have not approved it for medical use. Material sold internationally is therefore usually labeled as a research chemical rather than a medicine. Peer-reviewed publications come predominantly from Russian laboratories, and sample sizes are generally small. Whether the compound produces comparable effects under independent, well-controlled replication remains an open question that the broader literature has not settled.
In addition, composite materials incorporating MOFs with polymers, carbon materials, or magnetic nanoparticles have been developed to improve mechanical stability, facilitate recovery, and enhance overall treatment efficiency. Despite these promising applications, several challenges remain for the large-scale implementation of MOFs in water treatment systems. These include limited stability in aqueous environments for certain frameworks, the cost and scalability of synthesis, and the need for improved durability under realistic operating conditions . Ongoing research efforts are therefore focused on developing more robust MOF structures and scalable production methods to enable their practical deployment in water purification technologies.
Albert Pike lost confidence in Cassard's performance. In 1861, he sent another Cuban named Vicente Antonio de Castro back to Cuba to take over and "...regularize any error that Andres Cassard might have committed in organizing the bodies of Cuba, and to establish that peace and harmony that should exist among the ancients in the Ancient and Accepted Scottish Rite." Albert Pike and the Grand Lodge of South Carolina became increasingly embroiled in the American Civil War. Pike served as a General in the Confederate States Army, and de Castro began acting more autonomously. Instead of withdrawing from Freemasonry, however, Pike sought to make Confederate South Carolina the epicentre of the entire Masonic world. de Castro, when he observed the currents within Colon Freemasonry, saw that even though the Grand Lodge and the Supreme Council disagreed on much of the issues in society, they were mostly led by Spanish loyalists desiring that Spain remain a part of Cuba's future. Historians note the discord, because before the Civil War, Albert Pike had long been a proponent of Manifest destiny and a soldier in the Westward Expansion – but the Lodges he created were still loyal to Spain. Still at the forefront of the debate was the institution of slavery. On March 28, 1862, instead of co-organizing with the Colon bodies, de Castro created an entirely new body called the Supremo Consejo y Gran Oriente de Cuba y Las Antillas (GOCA) (English: Supreme Council and Grand Orient of Cuba and the Antilles).
== Research == Stem cell therapy may represent a treatment for promoting the healing of diabetic foot ulcers. Diabetic foot ulcers develop their own, distinctive microbiota. Investigations into characterizing and identifying the phyla, genera, and species of nonpathogenic bacteria or other microorganisms populating these ulcers may help identify one group of microbiota that promotes healing. The recent advances in epigenetic modifications, with special focus on aberrant macrophage polarisation, are giving increasing evidence that epigenetic modifications might play a vital role in changing the treatment of diabetic foot ulcer in the near future.
Sources: en.wikipedia.org
The production of copra – removing the shell, breaking it up, drying – is usually done where the coconut palms grow. Copra can be made by smoke drying, sun drying, or kiln drying. Hybrid solar drying systems can also be used for a continuous drying process. In a hybrid solar drying system, solar energy is utilized during daylight and energy from burning biomass is used when sunlight is not sufficient or during night time. Sun drying requires little more than racks and sufficient sunlight. Halved nuts are drained of water, and left with the meat facing the sky; they can be washed to remove mold-creating contaminants. After two days the meat can be removed from the shell with ease, and the drying process is complete after three to five more days (up to seven in total). Sun drying is often combined with kiln drying, eight hours of exposure to sunlight means the time spent in a kiln can be reduced by a day and the hot air the shells are exposed to in the kiln is more easily able to remove the remaining moisture. This process can also be done in reverse order: partially drying the copra in the kiln, and finishing the process with sunlight. Starting with sun drying requires careful inspection to avoid contamination with mold while starting with kiln-drying can harden the meat and prevent it from drying out completely in the sun. In India, small but whole coconuts can be dried over the course of eight months to a year, and the meat inside removed and sold as a whole ball. Meat prepared in this fashion is sweet, soft, oily and is cream-coloured instead of being white.
=== Survival without dialysis === People who decide against dialysis treatment when reaching end-stage chronic kidney disease could survive several years and experience improvements in their mental well-being in addition to sustained physical well-being and overall quality of life until late in their illness course. However, use of acute care services in these cases is common and intensity of end-of-life care is highly variable among people opting out of dialysis.
John Scudder Sr., established the Christian Medical College and Hospital in Vellore in 1900, which has since become one of India's leading medical institutions. The Scudder family's enduring commitment to healthcare and education has left a lasting impact on India's social and medical landscape, inspiring generations of missionaries and healthcare professionals. The YMCA played a significant role in encouraging the development of sport in the princely states, as well as helping to improve agricultural output in rural areas.
Sources: en.wikipedia.org
PET imaging with oxygen-15 indirectly measures blood flow to the brain. In this method, increased radioactivity signal indicates increased blood flow which is assumed to correlate with increased brain activity. Because of its two-minute half-life, oxygen-15 must be piped directly from a medical cyclotron for such uses, which is difficult. PET imaging with FDG takes advantage of the fact that the brain is normally a rapid user of glucose. Standard FDG PET of the brain measures regional glucose use and can be used in neuropathological diagnosis. Brain pathologies such as Alzheimer's disease greatly decrease brain metabolism of both glucose and oxygen in tandem. Therefore FDG PET of the brain may also be used to successfully differentiate Alzheimer's disease from other dementing processes, and also to make early diagnoses of Alzheimer's disease. The advantage of FDG PET for these uses is its much wider availability. In addition, some other fluorine-18 based radioactive tracers can be used to detect amyloid-beta plaques, a potential biomarker for Alzheimer's in the brain. These include florbetapir, flutemetamol, Pittsburgh compound B (PiB) and florbetaben. PET imaging with FDG can also be used for localization of "seizure focus". A seizure focus will appear as hypometabolic during an interictal scan. Several radiotracers (i.e.
=== Microfaunal interactions === The apothecia of Xanthoria parietina also host microscopic animals. Members of the rotifer genus Philodina have been observed feeding on the lichen's ascospores present on apothecial surfaces. Individual rotifers can accumulate several dozen spores, and when ingesting 20 or more spores, about 15% remain viable and capable of germination after excretion. These findings indicate that rotifers may act as dispersal vectors, dislodging and releasing viable spores in new locations.
=== Lodotra === "Lodotra" is the brand name of an oral formulation, which releases prednisone four hours after ingestion. It is indicated for rheumatoid arthritis with morning stiffness. Taken at 10 p.m., it releases the drug at around 2 a.m. The plasmic peak level is reached at 4 a.m., which is considered to be the optimal time for relieving morning stiffness. The drug was approved in the European Union, in January 2009.
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.
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.