If you have been reading about electrospray ionization and want a single page that covers the useful parts, this is it: definitions, context, how it is studied, and the questions that come up repeatedly.
Last reviewed on 2026-04-14. Where a claim depends on a specific study, the study is described rather than over-claimed.
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.
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.
| Property | Value | Notes |
|---|---|---|
| Solubility | Freely soluble in water | Also in aqueous buffers |
| Typical purity (HPLC) | 95 percent or higher | Lot-dependent |
| Dry powder storage | Minus 20 degrees Celsius | Sealed, dry, protected from light |
| Solution storage | 2 to 8 degrees Celsius | Short-term use |
| Identity confirmation | Mass spectrometry | ESI or MALDI-TOF |
Outside its country of origin the compound is generally handled as a research chemical rather than an approved medicine. No regulatory approval from the United States Food and Drug Administration or the European Medicines Agency has been granted for human use. Identity and purity are normally checked by reverse-phase high-performance liquid chromatography, with mass spectrometry used to confirm the molecular mass. Lyophilised material is stored cold and desiccated, and repeated freeze-thaw cycles are avoided.
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.
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.
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.
Handling follows standard practice for research peptides. Material is weighed in a low-humidity environment because the powder absorbs atmospheric moisture. Purity is reported as the percentage area of the main peak in a chromatogram, with specifications commonly set at 95 percent or higher; values below that threshold indicate the presence of truncated or modified species. Residual trifluoroacetate from purification is often present and may affect mass balance. Certificates of analysis should state the analytical method, the column and gradient used, and the lot-specific retention time so that results can be compared across suppliers.
Identity and purity of selank are established with reversed-phase high-performance liquid chromatography coupled to mass spectrometry. The peptide elutes from C18 columns with acetonitrile gradients in water containing trifluoroacetic acid or formic acid, and detection is usually performed by ultraviolet absorbance near 214 nm. Electrospray ionization in positive mode gives a doubly protonated ion near m/z 377, consistent with a mass of about 752 Da. Amino acid analysis or tandem mass spectrometry of fragment ions confirms the sequence. Because the molecule has no aromatic residues, it lacks a usable 280 nm chromophore, so low-wavelength detection or mass spectrometry is required.
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.
In June 2013 Pfizer's patent on sildenafil citrate expired in some member countries of the European Union, including Austria, Denmark, France, Germany, Ireland, Italy, The Netherlands, Spain, Sweden, the United Kingdom, and Switzerland. A UK patent held by Pfizer on the use of PDE5 inhibitors (see below) as treatment of impotence was invalidated in 2000 because of obviousness; this decision was upheld on appeal in 2002.
== Further reading == Madelain V, Nguyen TH, Olivo A, de Lamballerie X, Guedj J, Taburet AM, et al. (August 2016). "Ebola Virus Infection: Review of the Pharmacokinetic and Pharmacodynamic Properties of Drugs Considered for Testing in Human Efficacy Trials". Clin Pharmacokinet. 55 (8): 907–23. doi:10.1007/s40262-015-0364-1. PMC 5680399. PMID 26798032.
=== Hydrothermal self-assembly === Graphene has been prepared by using a sugar like glucose, fructose, etc. This substrate-free "bottom-up" synthesis is safer, simpler and more environmentally friendly than exfoliation. The method can control the thickness, ranging from monolayer to multilayer, which is known as the "Tang-Lau Method".
Betula alleghaniensis – yellow birch (B. lutea) (eastern Canada, Great Lakes, upper eastern US, Appalachians) Betula caerulea – blue birch (northeast of North America) Betula cordifolia – mountain paper birch (eastern Canada, Great Lakes, New England US) Betula glandulosa – American dwarf birch (Siberia, Mongolia, Russian Far East, Alaska, Canada, Greenland, mountains of western US and New England, Adirondacks) Betula kenaica – Kenai birch ( Alaska, northwestern North America) Betula lenta – sweet birch, cherry birch, or black birch (Quebec, Ontario, eastern US) Betula michauxii – Newfoundland dwarf birch (Newfoundland, Labrador, Quebec, Nova Scotia) Betula minor – dwarf white birch (eastern Canada, mountains of northern New England and Adirondacks) Betula murrayana – Murray's birch (Great Lakes endemic) Betula nana – dwarf birch or bog birch (also in northern Europe and Asia) Betula neoalaskana – Alaska paper birch also known as Alaska birch or Resin birch (Alaska and northern Canada) Betula nigra – river birch or black birch (eastern US) Betula occidentalis – water birch or red birch (B. fontinalis) (Alaska, Yukon, Northwest Territories, western Canada, western US) Betula papyrifera – paper birch, canoe birch or American white birch (Alaska, most of Canada, northern US) Betula populifolia – gray birch (eastern Canada, northeastern US) Betula pumila – swamp birch (Alaska, Canada, northern US) Betula uber – Virginia round-leaf birch (southwestern Virginia)
=== Daily life === In addition to objects in hospital settings, other common fomites for humans are cups, spoons, pencils, bath faucet handles, toilet flush levers, door knobs, light switches, handrails, elevator buttons, television remote controls, pens, touch screens, common-use phones, keyboards and computer mice, coffeepot handles, countertops, drinking fountains, and any other items that may be frequently touched by different people and infrequently cleaned. Cold sores, hand–foot–mouth disease, and diarrhea are some examples of illnesses easily spread by contaminated fomites. The risk of infection by these diseases and others through fomites can be greatly reduced by simply washing one's hands. When two children in one household have influenza, more than 50% of shared items are contaminated with virus. In 40–90% cases, adults infected with rhinovirus have it on their hands.
Sources: en.wikipedia.org
=== Entertainment === The most popular forms of entertainment among Generation Z are playing video games, listening to music, surfing the Internet, and using social media networks. According to Asha Choksi, vice president of global research and insights for the educational publisher Pearson, about one in every three members of Generation Z spends at least four hours per day watching videos online. Data from the Bureau of Labor Statistics show that while people aged 15 to 24 spent more time playing video games in 2018, the time spent on computers and televisions remained virtually unchanged.
Recent studies demonstrated that caspase-1-mediated pyroptosis, a highly inflammatory form of programmed cell death, drives CD4 T-cell depletion and inflammation by HIV. These are the two signature events that propel HIV disease progression to AIDS. Pyroptosis appears to create a pathogenic vicious cycle in which dying CD4 T cells and other immune cells (including macrophages and neutrophils) release inflammatory signals that recruit more cells into the infected lymphoid tissues to die. The feed-forward nature of this inflammatory response produces chronic inflammation and tissue injury. Identifying pyroptosis as the predominant mechanism that causes CD4 T-cell depletion and chronic inflammation, provides novel therapeutic opportunities, namely caspase-1 which controls the pyroptotic pathway. In this regard, pyroptosis of CD4 T cells and secretion of pro-inflammatory cytokines such as IL-1β and IL-18 can be blocked in HIV-infected human lymphoid tissues by addition of the caspase-1 inhibitor VX-765, which has already proven to be safe and well tolerated in phase II human clinical trials. These findings could propel development of an entirely new class of "anti-AIDS" therapies that act by targeting the host rather than the virus. Such agents would almost certainly be used in combination with ART. By promoting "tolerance" of the virus instead of suppressing its replication, VX-765 or related drugs may mimic the evolutionary solutions occurring in multiple monkey hosts (e.g.
Smashburger's menu focuses primarily on burgers, chicken sandwiches, black bean burgers and salads, with a variety of toppings and options that can be customized to a customer's taste. The company also offers a number of sides, including french fries, sweet potato fries, fried onions, and fried pickles, and "smash fries" which are topped with rosemary and olive oil. Many of the sandwiches are topped with an in-house "smash sauce" made with mayonnaise, mustard, pickles and lemon juice. Smashburger's main dessert item is a milkshake made with Häagen-Dazs ice cream. About 20 milkshakes are sold per 100 burgers. The chain experimented with a breakfast menu for a time but it found this to be unprofitable, accounting for just 10 percent of its revenue but 30 percent of expenses. Some of its specialized locations such as those in casinos do continue to offer breakfast menus. Smashburger also attempted a system for customers to fill out menu cards as they waited in line which was not successful.
The American Institute for Cancer Research (AICR) and World Cancer Research Fund International (WCRF) have stated that there is strong evidence that consuming salted foods including salt-preserved fish and salt-preserved foods in general increases risk of stomach cancer and that the high salt content of processed meat may result in damage to the stomach mucosal lining. The American Cancer Society have stated that "stomach cancer risk is increased in people whose diets include large amounts of foods preserved by salting, such as salted fish and meat and pickled vegetables." Additionally, an excessive intake of salt has a dose-response relationship with elevated blood pressure, increasing the risk of several cardiovascular diseases.
Experiments of other scientists, at first, produced the same results but later it became clear that the period of reinforced activity is followed by a period of decline. At the moment of the experiment Charles-Édouard Brown-Séquard was 72 years old. After the experiment he claimed he felt as if he became younger by 30 years. However, 5 years later he died. But other doctors picked up this method and it created the foundation for the development of hormone replacement therapy. 1903 Ilya Mechnikov coined the term "gerontology". The term originates from the Greek γέρων, geron, "old man" and -λογία, -logia, "study of". From 1897 to 1916 Mechnikov conducted many studies on the effect of acidified dairy products (especially Bulgarian yogurt and bacteria used for its production) on longevity and quality of life in old age. He developed the concept of probiotic diet that promotes long healthy life. In 1908 Mechnikov received the Nobel Prize for his work on immunology (adjacent area of his research). Adhering to his diet, Mechnikov lived a very long life compared to his short-lived relatives. 1914 Dr. Frank Lydston from Chicago performed human testis transplants on several patients, including himself, and said that there were some rejuvenating consequences (such as returning his gray hair to its original color and improving of sexual performance). These works remained little known. The work of Leo L. Stanley, that he began to do since 1919, received much more prominence (see further).
Sources: en.wikipedia.org
==== Physical education ==== Positive psychology aims to improve the quality of experiences. Within its framework, students could learn to become excited about physical activity. Playing comes naturally to children; positive psychology seeks to preserve this zest (a sense of excitement and motivation for life) for movement in growing and developing children. If offered in an interesting, challenging and pleasurable way, physical activity could internalize a feeling of happiness in students. Positive psychology's approach to physical activity could give students the means of acquiring an engaged, pleasant and meaningful life.
== Awards == 2023 Tung-Ho Outstanding Research Award, THS Foundation 2023 16th Taiwan Outstanding Women in Science Awards, Wu Chien Shiung Education Foundation & L'ORÉAL Taiwan 2022 Outstanding Research Award, National Science and Technology Council 2022 Outstanding Research Award, National Science and Technology Council 2021 National Innovation Award 2020 Taiwan Society for Mass Spectrometry Medal 2011 Taiwan Society for Mass Spectrometry Outstanding Scholar Award 2007 Federation of Asian Chemical Societies Distinguished Young Chemists Award 2006 Chinese Chemical Society Outstanding Young Investigator Award
The same Stictis fungus can form a lichen when algae are present (it was formerly classified in a separate lichen genus, Conotrema) or live as a saprobe (decay organism) when absent—yet in both cases it retains the same Latin name. These cases underscore that the mycobiont is the nomenclatural unit; the lichen is its ecological expression. The holobiont lens nonetheless shifts research toward how fungal–algal–microbial associations evolve. Topics such as photobiont switching—common among closely related Trebouxia strains but rare between major algal lineages—are tested for links with adaptation and speciation. Photobiont flexibility — a fungus's ability to switch algal partners — appears to vary. Many lichen-forming fungi can pair with multiple algae of the same general type (for example, different strains of Trebouxia, a genus of green algae). However, switching to a completely different type of algal partner (say, from a green alga to a cyanobacterium) is much rarer, and often coincides with a major evolutionary shift in the lichen.
The role of the other BDNF receptor, p75, is less clear. While the TrkB receptor interacts with BDNF in a ligand-specific manner, all neurotrophins can interact with the p75 receptor. When the p75 receptor is activated, it leads to activation of NFkB receptor. Thus, neurotrophic signaling may trigger apoptosis rather than survival pathways in cells expressing the p75 receptor in the absence of Trk receptors. Recent studies have revealed a truncated isoform of the TrkB receptor (t-TrkB) may act as a dominant negative to the p75 neurotrophin receptor, inhibiting the activity of p75, and preventing BDNF-mediated cell death.
Sources: en.wikipedia.org
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.
Freeze-dried material is kept frozen, often at minus 20 degrees Celsius, and protected from light and moisture. Dissolved peptide is refrigerated for short-term use. Repeated freeze-thaw cycles are avoided.
A certificate of analysis typically lists purity by HPLC, the confirmed mass, appearance, and sometimes water or counter-ion content. It documents results for a specific batch. Details vary by supplier.
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.