Intranasal delivery comes up often in conversation and rarely with the context attached. Here we lay out the basics in order, then work through the practical considerations.
Updated 2026-04-30. Numbers and descriptions here follow the published literature rather than marketing material.
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.
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.
Animal studies have examined behaviour in tests of anxiety, memory retention and stress response, and several report changes in neurotrophic or neurotransmitter-related markers. The human evidence base is much smaller, consisting mainly of short trials conducted in Russia with limited reporting in English-language journals. Sample sizes are modest and outcome measures vary between studies, so the findings are best described as preliminary. Independent replication under modern trial standards has not been widely reported.
| 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 |
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.
Dry powder is normally held at -20 degrees Celsius or lower, in a sealed container with desiccant and protection from light. Reconstituted solutions are usually kept at 2 to 8 degrees Celsius for short periods and frozen for longer ones. Proline residues at several positions are generally associated with some resistance to peptidase attack, but chemical stability still declines at neutral to alkaline pH and at elevated temperature. Exact shelf-life figures are product-specific and are not standardised across suppliers.
Identity and purity are usually assessed by reversed-phase high-performance liquid chromatography, with mass spectrometry used to confirm molecular mass and sequence information. Amino acid analysis and peptide mapping may supplement these methods. Certified reference standards are scarce, and many commercial lots are sold as research chemicals without a pharmacopoeial monograph. Regulatory treatment differs by country: Selank is a registered prescription medicine in Russia, while in the European Union and the United States it is not an approved drug and may fall under research-chemical or unapproved-product frameworks.
Selank is a hydrophilic peptide and dissolves readily in water and in aqueous buffers. The lyophilised powder is typically a white to off-white solid. Because short peptides are prone to hydrolysis and oxidation, handling benefits from limiting exposure to heat, moisture and strong light. Working solutions are commonly prepared in sterile water or saline, and repeated freeze-thaw cycles are avoided to reduce aggregation and loss of activity. These practices reflect general laboratory convention rather than published stability specifications.
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.
In 1800, France built Nautilus, a human-powered submarine designed by American Robert Fulton. They gave up on the experiment in 1804, as did the British, when they reconsidered Fulton's submarine design. In 1850, Wilhelm Bauer's Brandtaucher was built in Germany. It remains the oldest known surviving submarine in the world. In 1864, late in the American Civil War, the Confederate navy's H. L. Hunley became the first military submarine to sink an enemy vessel, the Union sloop-of-war USS Housatonic, using a gun-powder-filled keg on a spar as a torpedo charge. The Hunley also sank. The explosion's shock waves may have killed its crew instantly, preventing them from pumping the bilge or propelling the submarine. In 1866, Sub Marine Explorer was the first submarine to successfully dive, cruise underwater, and resurface under the crew's control. The design by German American Julius H. Kroehl (in German, Kröhl) incorporated elements that are still used in modern submarines. In 1866, Flach was built at the Chilean government's request by Karl Flach, a German engineer and immigrant. It was the fifth submarine built in the world and, along with a second submarine, was intended to defend the port of Valparaíso against attack by the Spanish Navy during the Chincha Islands War.
==== Medical and research uses ==== Radium (usually in the form of radium chloride or radium bromide) was used in medicine to produce radon gas, which in turn was used as a cancer treatment. Several of these radon sources were used in Canada in the 1920s and 1930s. However, many treatments that were used in the early 1900s are not used anymore because of the harmful effects radium bromide exposure caused. Some examples of these effects are anaemia, cancer, and genetic mutations. As of 2011, safer gamma emitters such as 60Co, which is less costly and available in larger quantities, are usually used to replace the historical use of radium in this application, but factors including increasing costs of cobalt and risks of keeping radioactive sources on site have led to an increase in the use of linear particle accelerators for the same applications. In the U.S., from 1940 through the 1960s, radium was used in nasopharyngeal radium irradiation, a treatment that was administered to children to treat hearing loss and chronic otitis. The procedure was also administered to airmen and submarine crew to treat barotrauma. Early in the 1900s, biologists used radium to induce mutations and study genetics. As early as 1904, Daniel MacDougal used radium in an attempt to determine whether it could provoke sudden large mutations and cause major evolutionary shifts. Thomas Hunt Morgan used radium to induce changes resulting in white-eyed fruit flies.
where v = 1/ρ is the specific volume of the fluid element. One can think of ∇ ∙ u as a measure of flow compressibility. Sometimes the negative sign is included in the term. The term 1/ρ2∇ρ × ∇p is the baroclinic term. It accounts for the changes in the vorticity due to the intersection of density and pressure surfaces. The term ∇ × (∇ ∙ τ/ρ) accounts for the diffusion of vorticity due to the viscous effects. The term ∇ × B provides for changes due to external body forces. These are forces that are spread over a three-dimensional region of the fluid, such as gravity or electromagnetic forces. (As opposed to forces that act only over a surface (like drag on a wall) or a line (like surface tension around a meniscus).
=== 2025 === In January 2025, before taking office, Trump stated he would not exclude using economic or military force against Greenland and that the United States needed the territory for national security. On 6 January 2025, he threatened to "tariff Denmark at a very high level" if it did not agree to Trump's plan. On 11 January, Donald Trump Jr. went on a private visit to Greenland. Local media reported that his entourage passed out MAGA hats to locals and attempted to speak to residents on a speakerphone. Pipaluk Lynge, a Greenlandic member of parliament, called the visit "staged". Berlingske reported that an American military person asked the Joint Arctic Command to provide information about Greenlandic infrastructure. In the following months, Republican congressman Buddy Carter introduced a bill in the United States Congress to advance efforts to annex Greenland and rename it Red, White, and Blueland and US vice president JD Vance visited, without invitation, the Pituffik Space Base, where he gave a speech about how Denmark had failed Greenlanders. Vance's visit was condemned by Greenlandic and Danish politicians, and described as a provocation. In connection with the visit, commander Susannah Meyers, the highest-ranking US officer in Greenland, said the Trump administration's threats against the Kingdom of Denmark "are not reflective of Pituffik Space Base". In response, Meyers was fired by Trump.
Macrophages are professional phagocytes and are highly specialized in removal of dying or dead cells and cellular debris. This role is important in chronic inflammation, as the early stages of inflammation are dominated by neutrophils, which expend themselves and are ingested by macrophages. Macrophages normally present themselves at the wound site within 2 days following the injury. The neutrophils are at first attracted to a site, where they perform their function and die, before they or their neutrophil extracellular traps are phagocytized by the macrophages. The first wave of neutrophils acts for approximately 2 days at the site and signals to attract macrophages. These macrophages will then ingest the aged neutrophils. The removal of dying cells is, to a greater extent, handled by fixed macrophages, which will stay at strategic locations such as the lungs, liver, neural tissue, bone, spleen and connective tissue, ingesting foreign materials such as pathogens and recruiting additional macrophages if needed. The phagocytosis and clearance of apoptotic remains is called efferocytosis and is also carried out by other cell types, not all of which are professional phagocytes. When a macrophage ingests a pathogen, the pathogen becomes trapped in a phagosome, which then fuses with a lysosome. Within the phagolysosome, enzymes and toxic peroxides digest the pathogen. However, some bacteria (such as Mycobacterium tuberculosis) have become resistant to these methods of digestion.
Sources: en.wikipedia.org
Observed values of viscosity vary over several orders of magnitude, even for common substances (see the order of magnitude table below). For instance, a 70% sucrose (sugar) solution has a viscosity over 400 times that of water, and 26,000 times that of air. More dramatically, pitch has been estimated to have a viscosity 230 billion times that of water.
In the above example, the combination of whole rice and canned chickpeas has no limiting amino acids. This means that consuming only rice and chickpeas, in these specific quantities of 306 g/day and 261 g/day respectively, for long periods of time, would easily combine to create complete protein, as it would not result in any of the essential amino acid deficiency. As the data of the example show, all essential amino acids are found in a specific plant. However, one or more of them may be limiting. For this reason, vegan and vegetarian diets need to be varied in terms of plants consumed.
Siege life took its toll on the defending soldiers and civilians, as food began to grow scarce after a few weeks. In Mafeking, Sol Plaatje wrote, "I saw horseflesh for the first time being treated as a human foodstuff." The cities also dealt with constant artillery bombardment, making the streets dangerous. Near the end of the siege of Kimberley, it was expected that the Boers would intensify their bombardment, so Rhodes displayed a notice encouraging people to go down into shafts of the Kimberley Mine for protection. The townspeople panicked, and people surged into the mineshafts constantly for a 12-hour period. Although the bombardment never came, this did nothing to diminish the anxious civilians' distress. The most well-heeled of the townspeople, including Rhodes, sheltered in the Sanatorium, site of the present-day McGregor Museum; the poorer residents, notably the black population, did not have any shelter from shelling. In retrospect, the Boers' decision to commit themselves to sieges (Sitzkrieg) was a mistake and an illustration of their lack of strategic vision. Of the seven sieges in the First Boer War, the Boers had prevailed in none. More importantly, it handed the initiative back to the British and allowed them to recover. Generally throughout the campaign, the Boers were too defensive and passive, wasting the opportunities they had for victory. Yet that passivity testified to the fact they had no desire to conquer British territory, but only to preserve their ability to rule in their own territory.
== Disorder and disease == Intrinsically unstructured proteins have been implicated in a number of diseases. Aggregation of misfolded proteins is the cause of many synucleinopathies and toxicity as those proteins start binding to each other randomly and can lead to cancer or cardiovascular diseases. Thereby, misfolding can happen spontaneously because millions of copies of proteins are made during the lifetime of an organism. The aggregation of the intrinsically unstructured protein α-synuclein is thought to be responsible. The structural flexibility of this protein together with its susceptibility to modification in the cell leads to misfolding and aggregation. Genetics, oxidative and nitrative stress as well as mitochondrial impairment impact the structural flexibility of the unstructured α-synuclein protein and associated disease mechanisms. Many key tumour suppressors have large intrinsically unstructured regions, for example p53 and BRCA1. These regions of the proteins are responsible for mediating many of their interactions. Taking the cell's native defense mechanisms as a model drugs can be developed, trying to block the place of noxious substrates and inhibiting them, and thus counteracting the disease.
Jessie Gordon, formerly McTavish, (born c.1940) is a Scottish retired nurse who was convicted in 1974 of murdering a patient with insulin, and of administering a variety of substances with intent to cause harm. The conviction was overturned on appeal in 1976. She was dubbed the "Angel of Death" by the press.
Sources: en.wikipedia.org
The Russian Empire organized its Cossacks into several voiskos (hosts), which lived along the Russian border and internal borders between Russian and non-Russian peoples. Each host originally had its own leadership, ranks, regalia, and uniforms. By the late 19th century, ranks were standardized following the example of the Imperial Russian Army. The ranks and insignia were kept after the 1988 law allowing the hosts to reform, and the 2005 law legally recognizing the hosts as a combat service. They are given below as per all military tickets that are standard for the Russian Army.
Rock wool (mineral wool) is the most widely used medium in hydroponics. Rock wool is an inert substrate suitable for both run-to-waste and recirculating systems. Rock wool is made from molten rock, basalt or 'slag' that is spun into bundles of single filament fibres, and bonded into a medium capable of capillary action, and is, in effect, protected from most common microbiological degradation. Rock wool is typically used only for the seedling stage, or with newly cut clones, but can remain with the plant base for its lifetime. Rock wool has many advantages and some disadvantages. The latter being the possible skin irritancy (mechanical) whilst handling (1:1000). Flushing with cold water usually brings relief. Advantages include its proven efficiency and effectiveness as a commercial hydroponic substrate. Most of the rock wool sold to date is a non-hazardous, non-carcinogenic material, falling under Note Q of the European Union Classification Packaging and Labeling Regulation (CLP). Mineral wool products can be engineered to hold large quantities of water and air that aid root growth and nutrient uptake in hydroponics; their fibrous nature also provides a good mechanical structure to hold the plant stable. The naturally high pH of mineral wool makes them initially unsuitable to plant growth and requires "conditioning" to produce a wool with an appropriate, stable pH.
== Soluble TCR == A soluble TCR is a TCR that has been made water-soluble using protein engineering. Such a protein is based on changing an existing TCR's chains to remove the transmembrane portions, leaving only the extracellular part. A number of techniques from protein engineering are then used to stabilize the complex and improve its binding characteristics. A soluble TCR can be used as an antigen-binding module, much like how monoclonal antibodies are used in medicine. Their advantage over antibodies is that they make use of the MHC/HLA display mechanism, allowing them to detect not only extracellular antigens, but also fragments of intracellular ones. On the other hand, they also face some restrictions in terms of applicable HLA genotypes due to them being made to target the complex of a MHC protein with the antigen fragment. One idea for overcoming this restriction is to instead target monomorphic HLA-like molecules such as HLA-E, MHC-related protein 1 (MR1) and cluster of differentiation 1 a, b, c and d (CD1a, CD1b, CD1c or CD1d). An example of a protein derived from soluble TCR is tebentafusp, approved by the US FDA in 2022. This designed protein contains a soluble TCR (αβ) targeting a fragment of gp100 presented by HLA-A*02:01 connected to a ScFv that binds CD3. As a result it causes T cells to activate in the vicinity of cells that present gp100, acting as a molecular glue (a bi-specific T-cell engager in the broad sense). It is only applicable to people with the HLA-A*02:01 genotype.
In 1999 its parent company reorganized and changed its name to PE Corporation, and the PE Biosystems Group (formerly again became publicly traded, as a tracking stock of its parent, along with its sister tracking stock company, Celera Genomics. In 2000 the parent became Applera Corporation. The Applied Biosystems name also returned that year, in the name change of the tracking stock from PE Biosystems Group to Applera Corporation-Applied Biosystems Group, an S&P 500 company, which remains as a publicly traded operating group within Applera Corp., along with its sibling operating group, Applera Corporation-Celera Group. Applera derives its name from the combination of its two component groups' names, Appl(iedCel)era In November 2008, a merger between Applied Biosystems and Invitrogen was finalized "creating a global leader in biotechnology reagents and systems". The new company was called Life Technologies.
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.
Most published work uses intranasal application, either as drops or as a nasal spray. Injection routes appear in a smaller set of animal experiments. Oral use is uncommon in the literature because peptide breakdown and poor absorption limit this route.