A practical reference on Certificate of analysis: what it is, how it behaves, what the literature reports, and where the honest uncertainties sit.
Reviewed 2026-07-18. Anything still debated is marked as such rather than presented as settled.
The primary structure of Selank is Thr-Lys-Pro-Arg-Pro-Gly-Pro, corresponding to the molecular formula C33H57N11O9 and a monoisotopic mass of roughly 751.9 daltons. The N-terminal threonine and the arginine residue in the fourth position are shared with tuftsin, which carries the sequence Thr-Lys-Pro-Arg. The three additional residues at the C-terminus, Pro-Gly-Pro, extend the chain and are associated with greater resistance to enzymatic degradation. This extension also separates Selank from the shorter parent peptide.
Naming conventions place Selank in the same research family as Semax, another Russian-developed peptide investigated for cognitive effects. The two compounds share a lineage but differ in sequence and in the biological systems proposed as their targets. Semax descends from ACTH fragments, whereas Selank descends from tuftsin. Publications sometimes identify Selank by its full peptide sequence or by laboratory codes rather than one uniform trade name. Because replication outside Russia is limited, reports on its properties are best read alongside the study design and the purity of the material tested.
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.
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.
| Property | Value | Notes |
|---|---|---|
| Molecular class | Synthetic heptapeptide | Stabilized analog of tuftsin |
| Sequence | Thr-Lys-Pro-Arg-Pro-Gly-Pro | Single-letter form: TKPRPGP |
| Molecular formula | C33H57N11O9 | Monoisotopic mass about 751.9 Da |
| Appearance | White to off-white powder | Typically supplied as lyophilized solid |
| Solubility | Freely soluble in water | Also soluble in common polar solvents |
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.
Once dissolved, the peptide is markedly less stable than the dry powder. Aqueous solutions are subject to backbone hydrolysis and to microbial growth when they are handled without sterile technique. Buffered solutions near neutral pH are common for short-term laboratory work, while acidic conditions are sometimes used to improve solubility. Analytical laboratories generally prepare working solutions fresh rather than storing them, and a residual water film left in a reopened vial can seed degradation even when the container appears dry.
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.
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.
Some nuclear safety agencies make recommendations about the use of thorium mantles and have raised safety concerns regarding their manufacture and disposal; the radiation dose from one mantle is not a serious problem, but that from many mantles gathered together in factories or landfills is.
According to results presented at the 2018 meeting of the American Diabetes Association, Afrezza increases the time that blood glucose levels remain in the optimal range (74–106 mg/dl), reducing both spikes in blood glucose and time in hypoglycemia in adults with type 1 diabetes, compared to insulin aspart.
=== 2018 === In 2018, Trump dismissed then-prevalent questions regarding his mental health, stating that he is a "very stable genius". As evidence of his mental capacities, he pointed to his business success, his victory over Republican competitors, and his election to the presidency against Hillary Clinton. Trump has also disputed claims he could not remember the name of a fallen soldier while talking to the widow, stating he has "one of the great memories of all time". In January 2018, Trump was examined by White House physician Ronny Jackson, who stated that he was in excellent health, although his weight and cholesterol level were higher than recommended, and that his cardiac assessment revealed no medical issues. Several independent cardiologists commented that Trump's weight, lifestyle, and LDL cholesterol ought to have raised serious concerns about his cardiac health. Trump's 2018 coronary CT calcium scan score indicates he has a form of heart disease called coronary artery disease, which is common for white males at his age.
Sources: en.wikipedia.org
British businessmen Hamish Harding and Shahzada Dawood, along with Dawood's son, Suleman, are confirmed as being aboard the missing submersible that disappeared during a voyage to see the wreck of the RMS Titanic two days earlier. 21 June – UK inflation figures for May 2023 show it remained higher than expected, at 8.7%. 22 June The Bank of England raises the official bank rate from 4.5% to 5%, the 13th consecutive rise, and a greater increase than economists had expected. The RMT announces three fresh days of strike action for 20, 22 and 29 July. 23 June Banks and building societies are summoned for a meeting with Jeremy Hunt as pressure grows on them to help people struggling with rising mortgage costs. A series of measures are agreed, offering more flexibility. Junior doctors in England announce a new five-day walkout from 13 to 18 July – the longest strike yet – over pay. Following a trial at Northampton Crown Court, Louis De Zoysa is convicted of the 2020 murder of police sergeant Matt Ratana. 24 June – The UK government holds an emergency COBRA meeting to discuss the Wagner Group rebellion in Russia. Sunak urges both sides to "be responsible and to protect civilians". 25 June A national technical fault affects the 999 service, meaning emergency services are unable to receive calls for around two hours. The service is fully restored by the evening. A spokesman for Sarah, Duchess of York says that she is recovering following surgery for breast cancer at King Edward VII's Hospital a few days earlier.
Computational proteomics is both an interdisciplinary field and a specialization of bioinformatics which uses computational techniques to study the proteome; in particular, computational proteomics is based on peptides identification techniques and allows to integrate vast quantities of heterogeneous data referred to proteins (e.g., identification of proteins, quantification, protein-protein interactions, structures...) and genomics (e.g., expression of genes and expression of proteins). The results of both proteomics and computational proteomics are used by biomedical engineering, biotechnology and Agri-Food Studies.
== N == NAD – NADH – NADPH – natural environment – natural selection – nephron – nervous system – neural plate – neural tube – neuron – neuroscience – neurospora crassa – neurotransmitter – neurula – neutral theory of molecular evolution – niche – nitrogen cycle – non-competitive inhibition – non-cyclic electron flow – nondisjunction – N-terminus – nuclear lamina – nucleolus – nucleon – nucleoside – nucleosome – nucleotide – nutrition
Sources: en.wikipedia.org
These increases are partially related to the COVID-19 pandemic, which continues to highlight the weaknesses of current food and health systems. It has contributed to food insecurity, increasing hunger worldwide; meanwhile, lower physical activity during lockdowns has contributed to increases in overweight and obesity. In 2020, experts estimated that by the end of the year, the pandemic could have double the number of people at risk of suffering acute hunger, around 130 million more undernourished people. Similarly, experts estimated that the prevalence of moderate and severe wasting could increase by 14% due to COVID-19; coupled with reductions in nutrition and health services coverage, this could result in over 128,000 additional deaths among children under 5 in 2020 alone. Although COVID-19 is less severe in children than in adults, the risk of severe disease increases with undernutrition. Other major causes of hunger include manmade conflicts, climate changes, and economic downturns.
=== Metabolism === H. influenzae uses the Embden–Meyerhof–Parnas (EMP) pathway for glycolysis and the pentose phosphate pathway, which is anabolic rather than catabolic. The citric acid cycle is incomplete and lacks several enzymes that are found in a fully functioning cycle. The enzymes missing from the TCA cycle are citrate synthase, aconitate hydratase, and isocitrate dehydrogenase. H. influenzae has been found in both aerobic and anaerobic environments, as well as environments with different pH's.
Craniocervical instability (CCI) is a medical condition characterized by excessive movement of the vertebra at the atlanto-occipital joint and the atlanto-axial joint located between the skull and the top two vertebra, known as C1 and C2. The condition can cause neural injury and compression of nearby structures, including the brain stem, spinal cord, vagus nerve, and vertebral artery, resulting in a constellation of symptoms. Craniocervical instability is more common in people with a connective tissue disease, including Ehlers–Danlos syndromes, osteogenesis imperfecta, and rheumatoid arthritis. It is frequently co-morbid with atlanto-axial joint instability, Chiari malformation, or tethered spinal cord syndrome. The condition can be brought on by physical trauma, including whiplash, laxity of the ligaments surrounding the joint, or other damage to the surrounding connective tissue.
== Treatment == Treatment of GAMT deficiency focuses on restoration of depleted brain creatine with oral creatine supplementation in pharmacologic doses, and removal of toxic intermediate GAA via ornithine supplementation and arginine- or protein-restricted diet. Sodium benzoate supplementation is also sometimes used to decrease GAA levels. All patients are reported to benefit from creatine supplementation, with possible improvements or stabilization in symptoms. Seizures appear to reduce more with dietary arginine restriction and ornithine supplementation. Despite treatment, none of the patients have been reported to return to completely normal developmental level, if significant damage had taken place before treatment. Prior to the addition of GAMT deficiency to newborn screening panels, younger siblings of affected individuals may have been tested at birth and treated early. This early treatment can result in outcomes that are very close to normal.
Sources: en.wikipedia.org
Selank is a synthetic heptapeptide designed as a stabilized analog of the natural tetrapeptide tuftsin. It has been investigated mainly for anxiolytic and cognitive effects. It is not an approved pharmaceutical in most countries.
It was developed in Russia, at the Institute of Molecular Genetics of the Russian Academy of Sciences, during the 1990s. Most published research originates from Russian institutions. Independent international replication remains limited.
Tuftsin is a natural tetrapeptide with the sequence Thr-Lys-Pro-Arg that participates in immune signaling. Selank extends that sequence with Pro-Gly-Pro at the C-terminus. The added residues are linked to greater resistance to enzymatic breakdown.
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.