This is a working overview of heptapeptide, written for readers who want more than a one-paragraph summary but less than a textbook.
Reviewed 2025-11-17. Anything still debated is marked as such rather than presented as settled.
Selank is a synthetic heptapeptide with the sequence Thr-Lys-Pro-Arg-Pro-Gly-Pro. It was designed at the Institute of Molecular Genetics of the Russian Academy of Sciences as a structural analogue of tuftsin, a naturally occurring tetrapeptide fragment of the immunoglobulin heavy chain. The added Pro-Gly-Pro tail was intended to slow enzymatic degradation and extend biological activity. In Russia it is registered as an anxiolytic nasal preparation, while regulators elsewhere have not approved it for clinical use.
Proposed mechanisms centre on modulation of the GABAergic system, with reports of altered expression of genes related to GABA-A receptor subunits and changed monoamine turnover. Some studies describe inhibition of enkephalinase, the enzyme that degrades endogenous enkephalins, which may prolong opioid peptide signalling. Effects on brain-derived neurotrophic factor and on cytokine expression have also been reported. These findings come largely from animal models and small human studies, and the precise primary target remains unresolved.
Published clinical evidence is limited. Most controlled trials were conducted in Russia, enrolled modest numbers of participants, and appeared in Russian-language journals, which restricts independent verification. Reported outcomes include lower anxiety scores, improved attention and memory measures, and changes in fatigue ratings. Reviews written in English note methodological limitations such as small samples and inconsistent endpoints. Whether the compound produces clinically meaningful benefit relative to established anxiolytics is therefore an open question rather than an established finding.
Peptide bonds are vulnerable to protease attack, and Selank is no exception. Measured half-life in serum is short, on the order of minutes in several reports, which explains why intranasal administration is the common route described in the literature. Absorption across the nasal mucosa partially bypasses first-pass hepatic metabolism. Quantitative data on human bioavailability remain limited and are difficult to compare across studies.
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.
| Property | Value | Notes |
|---|---|---|
| Molecular formula | C33H57N11O9 | Free peptide form |
| Molecular mass | About 751.9 Da | Calculated average mass |
| Amino acid sequence | Thr-Lys-Pro-Arg-Pro-Gly-Pro | Single-letter form TKPRPGP |
| Structural basis | Tuftsin analogue | Extended version of a natural tetrapeptide |
| Development origin | Russian Academy of Sciences | Work carried out from the 1980s onward |
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.
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.
He further argued: "Putin cares no more about a few thousand South Ossetians than he does about Kosovo's Serbs." Kagan wrote that Russia "has precipitated a war against Georgia by encouraging South Ossetian rebels to raise the pressure on Tbilisi and make demands that no Georgian leader could accept." He concluded that "Historians will come to view Aug. 8, 2008, as a turning point" because it "marked the official return of history". On 11 August 2008, journalist Ian Trainor wrote for The Guardian that Vladimir Putin did not respect the independence of Georgia and hated Georgian president Mikheil Saakashvili even more than Saakashvili's predecessor Eduard Shevardnadze whom Putin had held responsible for the dissolution of the Soviet Union. Saakashvili had been warning that a war would come after his April 2008 contact with Putin. Trainor concluded, "The Russians, the Georgians, the Europeans and the Americans are all responsible for the mess. There is only one victor, Vladimir Putin." On 16 August 2008, Ian Traynor wrote that the war in Georgia was "the biggest victory in eight years of what might be termed Putinism".
Stem-cell therapy uses stem cells to treat or prevent a disease or condition. As of 2024, the only FDA-approved therapy using stem cells is hematopoietic stem cell transplantation. This usually takes the form of a bone marrow or peripheral blood stem cell transplantation, but the cells can also be derived from umbilical cord blood. Research is underway to develop various sources for stem cells as well as to apply stem-cell treatments for neurodegenerative diseases and conditions such as diabetes and heart disease. Stem-cell therapy has become controversial following developments such as the ability of scientists to isolate and culture embryonic stem cells, to create stem cells using somatic cell nuclear transfer, and their use of techniques to create induced pluripotent stem cells. This controversy is often related to abortion politics and human cloning. Additionally, efforts to market treatments based on transplant of stored umbilical cord blood have been controversial.
=== Incubation period === The delay between the consumption of contaminated food and the appearance of the first symptoms of illness is called the incubation period. This ranges from hours to days (and rarely months or even years, such as in the case of listeriosis or bovine spongiform encephalopathy), depending on the agent, and on how much was consumed. If symptoms occur within one to six hours after eating the food, it suggests that it is caused by a bacterial toxin or a chemical rather than live bacteria. The long incubation period of many foodborne illnesses tends to cause those affected to attribute their symptoms to gastroenteritis. During the incubation period, microbes pass through the stomach into the intestine, attach to the cells lining the intestinal walls, and begin to multiply there. Some types of microbes stay in the intestine, some produce a toxin that is absorbed into the bloodstream, and some can directly invade the deeper body tissues. The symptoms produced depend on the type of microbe. In cases of foodborne illness, particularly traveler's diarrhea, symptoms often result from the immune system's response rather than direct pathogen damage. This inflammatory response can lead to post-infectious irritable bowel syndrome (PI-IBS), where 3–20% of affected individuals develop chronic gastrointestinal symptoms even after the pathogen is cleared. This suggests that the body's immune reaction, particularly inflammation, plays a significant role in both acute symptoms and long-term effects of foodborne illness.
Next, he co-starred in the action Lucy (2014), about a woman (Scarlett Johansson) who gains psychokinetic abilities when a nootropic drug is absorbed into her bloodstream. Freeman plays Professor Samuel Norman, who helps her research the condition. Producer Virginie Silla wanted Freeman for the part because of his experience in portraying a character of wisdom. "He was the perfect actor", she said. Upon the release of Lucy, critical reception ranged from mixed-to-positive. In the same year Freeman appeared in Dolphin Tale 2, the sequel to 2011's Dolphin Tale, and 5 Flights Up, a comedy-drama. At the end of 2014, Freeman appeared as himself, among other celebrities, in the documentary Lennon or McCartney.
Sources: en.wikipedia.org
==== Australia ==== In 2020, SBS reported that such markets were once common in Australia and were gradually shut down over time as abattoirs were centralised and moved away from cities. Media outlets Daily Mercury and Herald Sun, as well as Agriculture Minister David Littleproud and Leader of the Labor Party Anthony Albanese, have described various fresh meat, seafood, and produce markets in Australia, such as the Sydney Fish Market and Melbourne Fish Market, as wet markets in response to international calls to ban wet markets.
Cannabis has been used in traditional medicine over centuries. Today, cannabis is subjected to medical research mostly concentrating on the cannabinoids THC and CBD. The cannabis varieties used for the production of the hemp juice such as cannabis sativa are high in CBD content. Hemp juice can also be added into crèmes and gels, and used as an eczema treatment.
=== Books === In September 2019, Sinclair published Lifespan: Why We Age – and Why We Don't Have To co-written with journalist Matthew LaPlante and translated into 18 languages. This was also released as an audiobook on Audible and read by Sinclair. Sinclair broadly discusses his longevity practices on social media and includes them in his book. They include daily doses of nicotinamide mononucleotide (NMN) and resveratrol, which Sinclair claims are activators of SIRT1.
=== Terror management === Terror management theory maintains that people suffer cognitive dissonance (anxiety) when they are reminded of their inevitable death. Through terror management, individuals are motivated to seek consonant elements – symbols which make sense of mortality and death in satisfactory ways (i.e. boosting self-esteem). Research has found that strong belief in religious or secular meaning systems affords psychological security and hope. It is moderates (e.g. agnostics, slightly religious individuals) who likely suffer the most anxiety from their meaning systems. Religious meaning systems are especially adapted to manage anxiety about death or dying because they are unlikely to be disconfirmed (for various reasons), they are all encompassing, and they promise literal immortality. Whether emotional effects are beneficial or adverse seems to vary with the nature of the belief. Belief in a benevolent God is associated with lower incidence of general anxiety, social anxiety, paranoia, obsession, and compulsion whereas belief in a punitive God is associated with greater symptoms. (An alternative explanation is that people seek out beliefs that fit their psychological and emotional states.) Citizens of the world's poorest countries are the most likely to be religious, and researchers suggest this is because of religion's powerful coping abilities. Luke Galen also supports terror management theory as a partial explanation of the above findings.
=== Genetics === Habitat fragmentation has been shown to have minimal effect on the genetic diversity and gene flow of the North American woodland violet Viola pubescens. This may be partially attributed to the ability of Viola pubescens to continue to persist within a largely agricultural matrix. This trend of unexpectedly high genetic diversity is also observed in Viola palmensis, a Canary Island endemic known only from a 15 square kilometer range on La Palma island. High levels of genetic diversity within these species indicate that these plants are outcrossing, even though many violet species can produce many clonal offspring throughout the year via cleistogamous flowers. Plants that produce copious amounts of clonal seeds from cleistogamous flowers often experience increased levels of inbreeding. These reportedly high rates of outcrossing and genetic diversity indicate that these violets are strong competitors for pollinators during the early spring when they are in bloom and that those pollinators can travel considerable distances between often fragmented populations.
Sources: en.wikipedia.org
==== Microfluidic systems ==== There are two main microfluidic systems that are used to sequence DNA; droplet based microfluidics and digital microfluidics. Microfluidic devices solve many of the current limitations of current sequencing arrays. Abate et al. studied the use of droplet-based microfluidic devices for DNA sequencing. These devices have the ability to form and process picoliter sized droplets at the rate of thousands per second. The devices were created from polydimethylsiloxane (PDMS) and used Forster resonance energy transfer, FRET assays to read the sequences of DNA encompassed in the droplets. Each position on the array tested for a specific 15 base sequence. Fair et al. used digital microfluidic devices to study DNA pyrosequencing. Significant advantages include the portability of the device, reagent volume, speed of analysis, mass manufacturing abilities, and high throughput. This study provided a proof of concept showing that digital devices can be used for pyrosequencing; the study included using synthesis, which involves the extension of the enzymes and addition of labeled nucleotides. Boles et al. also studied pyrosequencing on digital microfluidic devices. They used an electro-wetting device to create, mix, and split droplets. The sequencing uses a three-enzyme protocol and DNA templates anchored with magnetic beads. The device was tested using two protocols and resulted in 100% accuracy based on raw pyrogram levels. The advantages of these digital microfluidic devices include size, cost, and achievable levels of functional integration.
As one of the largest cities in the Southern Appalachian region, Knoxville had long been a nexus between the surrounding rural mountain hinterland and the major industrial centers of the North, and thus had long been home to a thriving wholesaling (or "jobbing") market. Rural merchants from across East Tennessee purchased goods for their general stores from Knoxville wholesalers. With the arrival of the railroad, the city's wholesaling sector expanded rapidly, with over a dozen firms in operation by 1860, and 50 by 1896. In 1866, Knoxville-based wholesaler Cowan, McClung and Company was the most profitable company in the state. By the late-1890s, Knoxville had the third-largest wholesaling market in the South. The railroad also led to a boom in the quarrying and production of Tennessee marble, a type of crystalline limestone found in abundance in the ridges surrounding Knoxville. By the early 1890s, twenty-two quarries and three finishing mills were in operation in Knox County alone, and the industry as a whole was generating over a million dollars in annual profits. Tennessee marble was used in monumental construction projects across the nation, earning Knoxville the nickname, "The Marble City," during the late 19th century. The Flag of Knoxville, Tennessee incorporates the color white to symbolize marble and displays a derrick used in marble mining.
== Composition == OFM comprises more than 24 collagens (most notably types I and III), but also contains many growth factors, polysaccharides and proteoglycans that naturally exist as part of the extracellular matrix and play important roles in wound healing and soft tissue repair. The composition includes more than 150 different proteins, including elastin, fibronectin, glycosaminoglycans, basement membrane components, and various growth factors, such as vascular endothelial growth factor (VEGF), fibroblast growth factor (FGF) and platelet derived growth factor (PDGF). OFM has been shown to recruit mesenchymal stem cells, stimulate cell proliferation, angiogenesis and vascularogenesis, and modulate matrix metalloproteinase and neutrophil elastase. The porous structure of OFM has been characterized by differential scanning calorimetry (DSC), scanning electron microscopy (SEM), atomic force microscopy (AFM), histology, Sirius Red staining, small-angle x-ray scattering (SAXS), and micro computerized topography (MicroCT). OFM has been shown to contain residual vascular channels that facilitate blood vessel formation through angioconduction.
The converge of affordable technology from POS industry, cloud infrastructure, mobile platforms and low cost bandwidth is largely fuelling the adoption of technology by small retailers. Entrepreneurs are building highly affordable technology products which are likely to bridge the digital divide between online and offline retail. Amartya Sen, the Indian-born Nobel Prize–winning economist, in a December 2011 interview claims foreign direct investment in multi brand retail can be good thing or bad thing, depending on the nature of the investment. Quite often, claims Professor Sen, FDI is a good thing for India.
Sources: en.wikipedia.org
It is a seven-amino-acid peptide, Thr-Lys-Pro-Arg-Pro-Gly-Pro, produced by chemical synthesis rather than extracted from biological tissue. Its design is based on tuftsin, a natural immunomodulatory tetrapeptide. The C-terminal Pro-Gly-Pro segment is a common stabilising motif in short regulatory peptides.
The core four residues correspond to tuftsin, which occurs naturally as part of immunoglobulin G. The full seven-residue sequence, however, is not a known endogenous peptide. It is a laboratory-designed analogue intended to combine tuftsin-like activity with greater resistance to breakdown.
No single receptor has been confirmed as the primary target. Reports describe involvement of the GABAergic system, interference with enkephalin degradation, and shifts in neurotrophic factor expression. Because these observations come from different models and assays, they have not yet been integrated into one accepted mechanism.
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.