The short version of mass spectrometry fits in a sentence. The long version — which is the one that helps — is below.
This page was last updated on 2025-10-18 and is reviewed periodically as new material appears.
Reversed-phase high-performance liquid chromatography is the standard technique for estimating peptide purity. The result is a peak-area percentage, which describes how much of the detected material elutes as the main peak in one run. Mass spectrometry confirms the molecular mass and can reveal truncated, adducted, or otherwise modified species. Amino acid analysis or tandem mass spectrometry can address sequence fidelity when identity is in doubt. None of these measurements, taken alone, establishes that a sample is fit for any specific purpose.
Lyophilized selank is normally supplied as a dry powder and is considered stable for extended periods when kept cold and dry. Moisture uptake is the main practical threat, because absorbed water promotes both hydrolysis and aggregation in the solid state. Vials are usually warmed to room temperature before opening so that condensation does not form on the powder. Supplier documentation commonly specifies -20 °C for routine storage, with -80 °C used for material intended to be archived for years.
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.
Selank is a synthetic heptapeptide developed in Russia as a structural analogue of tuftsin, a naturally occurring immunomodulatory tetrapeptide. Its sequence, Thr-Lys-Pro-Arg-Pro-Gly-Pro, keeps the tuftsin core at the N-terminus and appends a Pro-Gly-Pro tail. Researchers at the Institute of Molecular Genetics in Moscow synthesized the compound during the 1990s while searching for peptides with combined anxiolytic and immunomodulatory activity. The added tail was intended to resist enzymatic cleavage and prolong the molecule's presence in circulation.
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.
| Property | Value | Notes |
|---|---|---|
| Typical purity specification | 95 percent or higher by RP-HPLC | Area percentage of the main peak |
| Identity confirmation | Electrospray ionization mass spectrometry | Observed mass compared with the theoretical value near 751.9 Da |
| Recommended dry storage | -20 °C, desiccated | -80 °C for multi-year archival material |
| Solution handling | Prepare fresh; avoid long storage | Sterile filtration reduces microbial load |
| Common synonyms | TKPRPGP; TP-7 | Sequence code and laboratory designation used interchangeably |
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.
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.
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.
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.
Tafamidis was shown to have a greater effect when started earlier in the disease course, when milder disease was present, as amyloid deposits in the heart were lower. Acoramidis also showed a reduction in mortality in those with TTR amyloidosis compared to placebo and a reduction in hospitalizations related to heart disease. Tafamidis is considered a first line option for the treatment of TTR amyloidosis. Ten to 20% of those with ATTR amyloidosis required pacemakers, usually due to high degree atrioventricular blocks. Observational cohort data showed that biventricular pacing preserves left ventricular function, heart failure symptom scores and mitral regurgitation incidence compared to right ventricular pacing. Ventricular arrythmia are common in those with AL and ATTR amyloidosis and are associated with a higher risk of sudden cardiac death. However, the use of implantable cardioverter defibrillators remains questionable in cardiac amyloidosis (both light chain and ATTR amyloidosis) and a mortality benefit has not been consistently shown. Outside of standard indications for implantable cardioverter defibrillators for those with heart failure, specific benefits in those with cardiac amyloidosis are not well established. Two to 5% of people with ATTR amyloidosis experience sudden cardiac death.
== History == Ecotutu is a Nigerian cleantech company focused on preserving fruits and vegetables in developing countries. It was founded in 2020 by Babajide Oluwase and Michael Akinsete. In 2021, Ecotutu was listed among ten finalists for the United Nations World Food Programme (WFP). In 2022, the company was named among the top three finalists at Global Entrepreneurship Summit and won the Zenith Bank FutureForward Tech Fair securing N20 million prize money.
=== July === July 14, 2009: Singapore Singapore experienced a seasonally adjusted and annualised growth of 20.4% in the second quarter as a result of increased pharmaceuticals production and construction, bringing the country out of the recession.
SLA SLA printing is a method in which a laser is shined upon a photoreactive liquid material to harden or polymerize. Instead of material being pushed through a nozzle or jet, material sits in a large basin and is slowly hardened. Due to its use of light to harden the material, SLA printers can offer a very high resolution at a lower speed when compared to other methods. This method is often used for protein scaffolding and providing structural support for other printed biological materials. Examples of bioinks used in SLA printers include fibrin, collagen, and some alginates.
Foods that contain nicotinamide include yeast, meat, milk, and green vegetables. Nicotinamide was discovered between 1935 and 1937. It is on the World Health Organization's List of Essential Medicines. Nicotinamide is available as a generic medication and over the counter. Commercially, nicotinamide is made from either nicotinic acid (niacin) or nicotinonitrile. In some countries, grains have nicotinamide added to them. Extraterrestrial nicotinamide has been found in carbonaceous chondrite meteorites.
Sources: en.wikipedia.org
Alkaptonuria Congenital disorders of joints Diabetes doubles the risk of having a joint replacement due to osteoarthritis, and people with diabetes have joint replacements at a younger age than those without diabetes. Ehlers–Danlos syndrome Injury to joints or ligaments (such as the ACL) Ligamentous deterioration or instability Marfan syndrome Obesity Joint infection
== Development == The usual development of CAD is when a cool high-pressure area wedges in east of a north-south oriented mountain chain. As a system approaches from the west, a persistent cloud deck with associated precipitation forms and lingers across the region for prolonged periods of time. Temperature differences between the warmer coast and inland sections east of the terrain can exceed 36 degrees Fahrenheit (20 degrees Celsius), with rain near the coast and frozen precipitation, such as snow, sleet, and freezing rain, falling inland during colder times of the year. In the Northern Hemisphere, two-thirds of such events occur between October and April, with summer events preceded by the passage of a backdoor cold front. In the Southern Hemisphere, they have been documented to occur between June and November. Cold air damming events which occur when the parent surface high-pressure system is relatively weak, with a central pressure below 1,028.0 millibars (30.36 inHg), or remaining a progressive feature (move consistently eastward), can be significantly enhanced by cloudiness and precipitation itself. Clouds and precipitation act to increase sea level pressure in the area by 1.5 to 2.0 mb ( 0.04 to 0.06 inHg). When the surface high moves offshore, the precipitation itself can cause the CAD event.
Bacterial display (or bacteria display or bacterial surface display) is a protein engineering technique used for in vitro protein evolution. Libraries of polypeptides displayed on the surface of bacteria can be screened using flow cytometry or iterative selection procedures (biopanning). This protein engineering technique allows us to link the function of a protein with the gene that encodes it. Bacterial display can be used to find target proteins with desired properties and can be used to make affinity ligands which are cell-specific. This system can be used in many applications including the creation of novel vaccines, the identification of enzyme substrates and finding the affinity of a ligand for its target protein. Bacterial display is often coupled with magnetic-activated cell sorting (MACS) or fluorescence-activated cell sorting (FACS) techniques. Competing methods for protein evolution in vitro are phage display, ribosome display, yeast display, and mRNA display. Bacteriophage display is the most common type of display system used although bacterial display is becoming increasingly popular as technical challenges are overcome. Bacterial display combined with FACS also has the advantage that it is a real-time technique.
== Test usage in the life insurance industry == The test has been widely used in the life insurance industry to screen applicants as part of the routine requirements when applying for a life insurance policy. It is also inexpensive and can be measured from blood samples routinely drawn as part of the application process. The test can be used to evaluate for a number of health conditions.
Sources: en.wikipedia.org
=== Olanzapine === Antipsychotic medications are increasingly used for schizophrenia, bipolar disorder, anxiety, and other psychiatric conditions Atypical antipsychotics are more commonly used than first generation antipsychotics because they decrease the risk of extrapyramidal symptoms, such as tardive dyskinesia, and have better efficacy. Olanzapine and atypical antipsychotics induce weight gain through increasing body fat. It also affects glucose metabolism, and several studies shows that it may worsen diabetes. A recent study shows that olanzapine inhibits GSK3 activity, suggesting olanzapine permits glycogen synthesis. A study of the effect of olanzapine on mouse blood glucose and glycogen levels showed a significant decrease in blood glucose level and elevation of glycogen level in mice, and the IC50% of olanzapine were 91.0 nm, which is considered a potent inhibitor. The study also illustrates that sub-chronic use of olanzapine results in potent inhibition of GSK3.
Some that partake in looksmaxxing also look for others to rate their appearance, with some engaging in anonymous message boards associated with incel subculture. This rating, together with one's perceived status and wealth, has been considered to be one's "sexual market value" (also known as SMV). Those who look to determine someone's attractiveness usually check for a variety of facial features. One of the features checked for in men is "hunter eyes", which refers to a positive canthal tilt, little to no upper eyelid exposure and low-set eyebrows, resembling the eye area of a predatorial animal. Additional features checked for include hollow cheeks, a defined jawline and "pursed lips". In order to achieve these features, some perform acts such as the aforementioned "mewing", rubbing against the orbital area, or getting surgery. On some incel forums, users deemed below average may be harassed, including being told to take their own lives. Additional terms have been coined by these communities in an effort to "dominate others". These phrases include "mogging", which refers to asserting dominance over another person based on their appearance, and being "Y-pilled", which refers to one viewing themselves as more masculine than the other and is a spin on the phrase "redpilled". The term also comes from "AMOG", which is a new acronym for "alpha male of the group". In the 2020s, the smellmaxxing trend became an offshoot of looksmaxxing.
Paralogous genes can shape the structure of whole genomes and thus explain genome evolution to a large extent. Examples include the Homeobox (Hox) genes in animals. These genes not only underwent gene duplications within chromosomes but also whole genome duplications. As a result, Hox genes in most vertebrates are clustered across multiple chromosomes with the HoxA-D clusters being the best studied. Another example are the globin genes which encode myoglobin and hemoglobin and are considered to be ancient paralogs. Similarly, the four known classes of hemoglobins (hemoglobin A, hemoglobin A2, hemoglobin B, and hemoglobin F) are paralogs of each other. While each of these proteins serves the same basic function of oxygen transport, they have already diverged slightly in function: fetal hemoglobin (hemoglobin F) has a higher affinity for oxygen than adult hemoglobin. Function is not always conserved, however. Human angiogenin diverged from ribonuclease, for example, and while the two paralogs remain similar in tertiary structure, their functions within the cell are now quite different. It is often asserted that orthologs are more functionally similar than paralogs of similar divergence, but several papers have challenged this notion. In collaborative work, Anton Yuryev and co-authors demonstrated that genome-wide protein–protein interaction networks contain a significantly higher frequency of self-interacting proteins (homodimers) and interactions between paralogous proteins than would be expected by chance.
As a consequence, the female-specific diversity of our genome would fit less well with geography and linguistics than would our male-specific component. [...] If that were to prove to be the case, then the common belief that we speak our mother's tongue should be revised in favor of the concept of a 'father's tongue'. Estella Poloni also presented the Father Tongue hypothesis at an international conference in Paris in April 2000. On the basis of this population genetic work, the Dutch historical linguist George van Driem elaborated the Father Tongue hypothesis in his ethnolinguistic publications and in population genetic publications which he has co-authored. At the Indo-Pacific Prehistory Association conference in Taipei in 2002 he proposed that
histone Any of a class of highly alkaline proteins responsible for packaging nuclear DNA into structural units called nucleosomes in eukaryotic cells. Histones are the chief protein components of chromatin, where they associate into eight-membered complexes which act as "spools" around which the linear DNA molecule winds. They play a major role in gene regulation and expression.
Sources: en.wikipedia.org
Sealed, desiccated storage at -20 °C or colder is the standard recommendation for research-grade material. Vials should reach room temperature before they are opened, which limits condensation. Repeated temperature cycling is discouraged.
A reported purity value reflects the share of the main peak in one chromatographic run and says nothing about identity. Confirming that the expected sequence is present requires a separate measurement such as mass spectrometry. Purity and identity are distinct questions.
A mass spectrum reports the molecular masses present in a sample and shows whether they match the value expected for selank, near 751.9 Da. It also flags common artifacts such as truncation or adduct formation. It does not establish correct stereochemistry or complete sequence order on its own.
Selank is a synthetic seven-amino-acid peptide modeled on tuftsin, a fragment of the immunoglobulin G heavy chain. It was designed in Russia to combine anxiolytic and immunomodulatory properties in one molecule.