certificate of analysis 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.
Last reviewed on 2026-03-18. Where a claim depends on a specific study, the study is described rather than over-claimed.
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.
Regulatory treatment varies by jurisdiction. In Russia the compound is a registered prescription product, while in the European Union and the United States it is generally handled as a research chemical without a marketing authorization. Suppliers therefore operate outside pharmaceutical oversight, and buyers rely on supplier documentation for purity and identity claims. Chain of custody and third-party testing are the main verification tools. Analysts note that the absence of a pharmacopoeial monograph for research-grade material limits standardization across vendors.
Purity assessment relies mainly on reverse-phase high-performance liquid chromatography with ultraviolet detection. Because the peptide lacks a strong chromophore, detection often uses backbone absorbance near 214 nm. Identity is confirmed by mass spectrometry, typically electrospray ionization or matrix-assisted laser desorption, comparing the measured mass against the expected value. Amino acid analysis can verify composition after acid hydrolysis. Diastereomer content and residual counterions are reported less often, although both can influence biological assays.
Lyophilized material is generally stable for extended periods when kept dry at or below minus twenty degrees Celsius. Working solutions are less stable, and common practice is to aliquot and freeze them so that repeated freeze-thaw cycles are avoided. Aqueous solutions are sensitive to pH extremes and to microbial growth, so short-term storage at refrigerator temperature is typical. Oxidation and hydrolysis are the principal degradation routes. Reconstitution with sterile water or a mild buffer is standard, and solutions should be protected from light.
| 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 |
Pharmacokinetic data are sparse and largely derived from animal work. After intranasal administration the peptide appears in plasma within minutes, and reported half-lives are short, on the order of minutes to tens of minutes. Degradation proceeds through ordinary proteolytic cleavage into constituent amino acids and smaller fragments. Direct evidence that intact Selank reaches brain tissue in meaningful amounts is limited, and the extent of blood-brain barrier penetration is debated. Some authors argue that fragments, not the parent peptide, carry much of the observed activity.
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.
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.
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.
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.
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.
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.
In response, the corporation aggressively executed a $200 million structural cost take-out program to mitigate rising supply chain costs and volatile tariff headwinds. Despite these efforts, annual net sales for fiscal 2025 fell to $15.52 billion, down from $16.60 billion in 2024. To stimulate demand, the company launched its largest pipeline of new product refreshes in over a decade, introducing more than 100 new appliances globally across its core brands, including KitchenAid, JennAir, and Maytag. In February 2026, Whirlpool announced a strategic recapitalization plan, launching concurrent public offerings of common stock and depositary shares totaling approximately $800 million. The net proceeds were aimed at deleveraging its balance sheet by paying down outstanding balances under its revolving credit facility and accelerating strategic investments in manufacturing automation. However, the company faced severe financial pressure in early 2026 due to rapid macroeconomic deterioration, shifting tariff landscapes, and high inventory reduction costs. In May 2026, Whirlpool reported a first-quarter GAAP net loss of $85 million, a steep reversal from the prior year's net earnings. To combat multi-year inflationary cost pressures, management announced a 10% domestic price increase in April 2026—its largest pricing action in a decade—with an additional 4% hike scheduled for July 2026.
Treatment of GDM with diet and insulin reduces health problems for the mother and child. Treatment of GDM is also accompanied by more inductions of labour. A repeat OGTT should be carried out 6 weeks after delivery, to confirm that diabetes has disappeared. Afterwards, regular screening for type 2 diabetes is advised. Lifestyle interventions include exercise, diet advice, behavioural interventions, relaxation, self-monitoring of glucose, and combined interventions. Women with gestational diabetes who receive lifestyle interventions seem to have less postpartum depression, and were more likely to reach their weight loss targets after giving birth, than women who had no intervention. Their babies are also less likely to be large for their gestational age, and have less percentage of fat when they are born. More research is needed to discover the most effective lifestyle interventions. Some women with GDM use probiotics, but it is very uncertain if there are any benefits in terms of blood glucose levels, high blood pressure disorders, or induction of labour. If a diabetic diet or G.I. Diet, exercise, and oral medication are inadequate to control glucose levels; insulin therapy may become necessary. The development of macrosomia can be evaluated during pregnancy by using sonography. Women who use insulin, with a history of stillbirth, or with hypertension are managed like women with overt diabetes.
== Case studies: environmental impact on hemocyanin levels == A 2003 study of the effect of culture conditions of blood metabolites and hemocyanin of the white shrimp Litopenaeus vannamei found that the levels of hemocyanin, oxyhemocyanin in particular, are affected by the diet. The study compared oxyhemocyanin levels in the blood of white shrimp housed in an indoor pond with a commercial diet with that of white shrimp housed in an outdoor pond with a more readily available protein source (natural live food) as well. Oxyhemocyanin and blood glucose levels were higher in shrimp housed in outdoor ponds. It was also found that blood metabolite levels tended to be lower in low activity level species, such as crabs, lobsters, and the indoor shrimp when compared to the outdoor shrimp. This correlation is possibly indicative of the morphological and physiological evolution of crustaceans. The levels of these blood proteins and metabolites appear to be dependent on energetic demands and availability of those energy sources.
Although scientifically obsolete because it does not meet the definition of a complementary color in which a neutral or black color must be mixed, it is still a model used in artistic environments, causing confusion about primary and complementary colors. It can be considered an approximation of the CMY color model. The RYB color model relates specifically to color in the form of paint and pigment application in art and design. Other common color models include the light model (RGB) and the paint, pigment and ink CMY color model, which is much more accurate in terms of color gamut and intensity compared to the traditional RYB color model, the latter emerging in conjunction with the CMYK color model in the printing industry.
The content of a collective agreement must include terms for an expiry date no longer than 4 years (even if the parties want an ongoing agreement), a dispute resolution clause, a term for employees to make "individual flexibility agreements" (so long as employees are "better off overall"), and a term on consultation on any "major workplace changes" that could impact employees or change hours of work. To assist, the Fair Work Regulations 2009 Schedule 2.3 prescribes a model consultation term. Under section 172, other negotiated content can be anything "pertaining to the relationship between an employer" and "employees", or unions, payroll deductions from wages for union membership dues, and how the agreement will operate. Several court decisions have unduly limited what counts as pertaining to the employment relationship, including not regulating trading hours as opposed to working time, how to deal with surpluses in a defined benefit superannuation fund, whether money was transferred to a union-controlled super-fund, and constraints on employing contract labour as opposed to equal treatment. Even more, the law restricts agreements on union rights of entry, varying restrictions on strike action, and terms requiring employers pay bargaining service fees for non-union members. Once made, an agreement covers all employees it is expressed to, and the agreement is legally binding with civil remedies for breach, with the right of the employer, any employee, and the union having standing to sue in federal court.
Sources: en.wikipedia.org
The production was noted (by Nehad Selaiha of the weekly Al-Ahram) not only for its unexpected change of plot at the very end but also for its chorus of one hundred who alternated their speech between Arabic and English. The translation used was that of George Theodoridis. US Latina playwright Caridad Svich's 2009 play Wreckage, which premiered at Crowded Fire Theatre in San Francisco, tells the story of Medea from the sons' point of view, in the afterlife. Paperstrangers Performance Group toured a critically acclaimed production of Medea directed by Michael Burke to U.S. Fringe Festivals in 2009 and 2010. Bart Lee's interpretation of Medea, renamed Medea, My Dear, was performed in Surrey and later toured the south of England from 2010 to 2011. Luis Alfaro's re-imagining of Medea, Mojada, world premiered at Victory Gardens Theater in 2013. Theatre Lab's production, by Greek director Anastasia Revi, opened at The Riverside Studios, London, on 5 March 2014. The Hungry Woman: A Mexican Medea by Cherríe Moraga takes elements of Medea and of other works. 14 July – 4 September 2014 London Royal National Theatre staging of Euripides in a new version by Ben Power, starring Helen McCrory as Medea, directed by Carrie Cracknell, music by Will Gregory and Alison Goldfrapp. 25 September – 14 November 2015 London Almeida Theatre a new adaptation by Rachel Cusk, starring Kate Fleetwood as Medea, directed by Rupert Goold. 17 February – 6 March 2016 in Austin at the Long Center for the Performing Arts starring Franchelle Stewart Dorn as Medea and directed by Ann Ciccolella.
are so-named partial half-lives of corresponding processes. Terms "partial half-life" and "partial mean life" denote quantities derived from a decay constant as if the given decay mode were the only decay mode for the quantity. The term "partial half-life" is misleading, because it cannot be measured as a time interval for which a certain quantity is halved. In terms of separate decay constants, the total half-life
==== Natural gas ==== Commonly, HIC of natural gas from the same well has a trend of δDmethane < δDethane < δDpropane < δDC4+. This is because most natural gas is thought to be generated by stepwise thermal cracking that is mostly irreversible and thus governed by normal kinetic isotope effects (KIE) that favor light isotopes. The same trend, known as "the normal order", holds for carbon isotopes in natural gas. For example, Angola gas reportedly has a methane δD range of −190‰ to −140‰, an ethane δD of −146‰ to −107‰, a propane δD of −116‰ to −90‰, and a butane δD of −118‰ to −85‰. However, some recent studies show that opposite patterns could also exist, meaning δDmethane > δDethane > δDpropane. This phenomenon is often called 'isotopic reversal' or 'isotopic rollover'. The isotopic order could also be partly reversed, like δDmethane > δDethane < δDpropane or δDmethane < δDethane > δDpropane. Burruss et al. found that in the deepest samples of northern Appalachian basin the hydrogen isotopic order for methane and ethane is reversed. Liu et al., also found partial reversal in oil-related gas from the Tarim Basin. The mechanism causing this reversal is still unknown. Possible explanations include mixing between gases of different maturities and sources, oxidation of methane, etc. Jon Telling et al., synthesized isotopically reversed (in both C and H) low-molecular alkanes using gas-phase radical recombination reactions in electrical discharge experiments, providing another possible mechanism. Methane is the main component of natural gas.
The other side of the strong economic growth of these years was the "property bubble" that it generated since the main economic "engine" was the construction of houses and the demand for them was due to the fact that many savers did not buy them to inhabit them but as an investment to sell them later at a higher price, thanks to the constant increase in their value. Also the acquisition of a home became one of the most pressing problems for many people, especially for young people. The favorable economic situation made it possible to make the maintenance of social spending (education, health, pensions) compatible with the reduction of the public deficit and with the reduction of direct taxes. On the subject of pensions, the PP reaffirmed the validity of the so-called Toledo Pact and presented in the Cortes a bill ─ which was passed in 1999 ─ for the automatic revaluation of pensions, and the Social Security also managed to overcome the deficit it had in 1995 thanks to the spectacular increase in the number of affiliates. The Aznar government did not obtain the same support when it proposed the reform of the 1985 Foreigners' Law and conversely, the events that took place in El Ejido in early 2000 ─ dozens of Moroccans were attacked by a large group of neighbors in response to the murder of a woman attributed to a mentally ill man of Maghrebi origin ─ highlighted the problem of xenophobia in relation to emigration in all its crudeness.
Sources: en.wikipedia.org
In drug manufacture, validation is a documented process to ensure a product meets its required specifications and quality. The process of establishing documentary evidence demonstrating that a procedure, process, or activity carried out in testing and then production maintains the desired level of compliance at all stages. In the pharmaceutical industry, it is very important that in addition to final testing and compliance of products, it is also assured that the process will consistently produce the expected results. The desired results are established in terms of specifications for outcome of the process. Qualification of systems and equipment is therefore a part of the process of validation. Validation is a requirement of food, drug and pharmaceutical regulating agencies such as the US FDA and their good manufacturing practices guidelines. Since a wide variety of procedures, processes, and activities need to be validated, the field of validation is divided into a number of subsections including the following:
== See also == Cantonese salted fish Cured fish Salted squid Dried and salted cod Brining Gibbing Pickling salt Spekesild (cured, salted Atlantic herring) Surströmming (lightly-salted soured Baltic herring)
== History == Wallerian degeneration is named after Augustus Volney Waller. Waller experimented on frogs in 1850, by severing their glossopharyngeal and hypoglossal nerves. He then observed the distal nerves from the site of injury, which were separated from their cell bodies in the brain stem. Waller described the disintegration of myelin, which he referred to as "medulla", into separate particles of various sizes. The degenerating axons formed droplets that could be stained, thus allowing for studies of the course of individual nerve fibres.
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.
Purity is usually reported as an HPLC area percentage, most often measured at 214 nm. Identity is confirmed separately by mass spectrometry. A certificate of analysis should state both the method and the observed value.