If you have been reading about mass spectrometry 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.
Updated 2025-10-31. Numbers and descriptions here follow the published literature rather than marketing material.
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.
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 |
|---|---|---|
| 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 |
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.
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.
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.
Pharmacokinetic data are limited. Like most short peptides, Selank is vulnerable to plasma and tissue peptidases, and its measured half-life in circulation is short, on a minutes scale. The Pro-Gly-Pro tail slows this degradation but does not eliminate it. Intranasal administration is the route described in most reports, with absorption through the nasal mucosa and a hypothesized path into the central nervous system that avoids the blood-brain barrier. Direct measurements of human brain exposure are unavailable, so distribution claims rest on inference from animal work.
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.
An adrenaline junkie is someone who "has a compulsive desire for extreme excitement". Such activities include extreme and risky sports, substance abuse, unsafe sex, and crime. The term relates to the increase in circulating levels of adrenaline during physiological stress. Such an increase in the circulating concentration of adrenaline is secondary to the activation of the sympathetic nerves innervating the adrenal medulla, as it is rapid and not present in animals where the adrenal gland has been removed. Although such stress triggers adrenaline release, it also activates many other responses within the central nervous system reward system, which drives behavioral responses; while the circulating adrenaline concentration is present, it may not drive behavior. Nevertheless, adrenaline infusion alone does increase alertness and has roles in the brain, including the augmentation of memory consolidation.
Current or previous treatment with anti-resorptive or anti-angiogenic therapy Expose bone or bone that can be probed through intra-oral or extra-oral fistula in the maxillofacial region that has persisted for longer than 8 weeks. No history of radiation therapy or metastatic disease to the jaw. Osteonecrosis, or localized death of bone tissue, of the jaws, is a rare potential complication in cancer patients receiving treatments including radiation, chemotherapy, or in patients with tumors or infectious embolic events. In 2003, reports surfaced of the increased risk of osteonecrosis in patients receiving these therapies concomitant with intravenous bisphosphonate. Matrix metalloproteinase-2 may be a candidate gene for bisphosphonate-associated osteonecrosis of the jaws, since it is the only gene known to be associated with both bone abnormalities and atrial fibrillation, another side effect of bisphosphonates. In response to the growing base of literature on this association, the United States Food and Drug Administration issued a broad drug class warning of this complication for all bisphosphonates in 2005.
In Australia, iced coffee may include syrup, cream, cocoa powder or coffee beans. The café style is something like an unblended milkshake, and may be made from espresso coffee or only coffee flavoring. Bushells has marketed a Coffee and Chicory Essence since the late 19th century, as has Bickfords since 1910. There are many brands of packaged iced coffee consisting of coffee, milk, and sweetener. In South Australia, Farmers Union Iced Coffee has outsold Coca-Cola and is one of the state's biggest brands. Pauls "Territory's Own" Iced Coffee is popular in the Northern Territory and Norco Real Iced Coffee is prominent in Northern New South Wales and South East Queensland. Other brands include Breaka, Big M, Brownes Chill, Moove, Masters, Dare, Max, Fleurieu, Rush, Oak and Ice Break.
=== Inertial effect and kinetic inductance === While a single electron exhibits zero effective mass in graphene, as the entire set of electrons is moved with an electric field, the Fermi disk shifts, with both the total kinetic energy
Channa is a genus of predatory fish in the family Channidae, commonly known as snakeheads, native to freshwater habitats in Asia. This genus contains about 50 scientifically described species. The genus has a wide natural distribution extending from Iraq in the west, to Indonesia and China in the east, and parts of Siberia in the Far East. A particularly high richness of species exists in Myanmar (Burma), Bangladesh and northeastern India, and many Channa species live nowhere else. In contrast, a few widespread species have been introduced to several regions outside their natural range, where they often become invasive. The large and medium-sized Channa species are among the most common staple food fish in several Asian countries, and they are extensively cultured. Apart from their importance as a food fish, snakeheads are consumed in some regions as a traditional medicine for wound healing and reducing postoperative pain and discomfort, and collected for the international aquarium pet trade. All snakeheads are highly predatory, and the diets of the various species of Channa include fish, amphibians (like frogs), snakes, rodents, birds, and invertebrates (insects and crustaceans). They have a labyrinth organ, which allows them to breathe air for short periods, and they use this adaptation to travel across land in the event that their habitat becomes inhospitable. They are mostly solitary or live in monogamous pairs that are highly aggressive towards outsiders of their own species, but C. pleurophthalma often occurs in small groups.
Sources: en.wikipedia.org
Vitamin B17: pseudoscientific name for the poisonous compound amygdalin, also known as "laetrile" or by the equally pseudoscientific name "nitrilosides" despite the fact that it is a single compound. Amygdalin can be found in various plants, but is most commonly extracted from apricot pits and other similar fruit kernels. Amygdalin is hydrolyzed by various intestinal enzymes to form, among other things, hydrogen cyanide, which is toxic to human beings when exposed to a high enough dosage. Some proponents claim that amygdalin is effective in cancer treatment and prevention, despite its toxicity and a lack of scientific evidence. Vitamin B20: L-carnitine. Vitamin Bf: carnitine. Vitamin Bm: myo-inositol, also called "mouse antialopaecia factor". Vitamin Bp: "antiperosis factor", which prevents perosis, a leg disorder, in chicks; can be replaced by choline and manganese salts. Vitamin BT: carnitine. Vitamin Bv: a type of B6 other than pyridoxine. Vitamin BW: a type of biotin other than d-biotin. Vitamin Bx: an alternative name for both pABA (see vitamin B10) and pantothenic acid.
The SRC collapsed in 1991 with the onset of the Somali Civil War. Instability continued through periods of reduced conflict under transitional governments in the early 2000s.At the end of 2006, a US-backed Ethiopian invasion overthrew the Islamic Courts Union (ICU), leading to the installation of the Transitional Federal Government of Somalia (TFG) in Mogadishu under an Ethiopian military occupation. The subsequent insurgency which emerged saw the ICU fragment into various rebel factions, including the militant group al-Shabaab, which waged a protracted conflict against Ethiopian forces, the two powers exchanging control of territories through mid-2012. A new provisional constitution was passed in August 2012, reforming Somalia as a federation and began reconstruction under the Federal Government of Somalia. Insurgents still control much of central and southern Somalia and influence government-controlled areas. Somalia is among the least developed countries in the world because of its low GDP per capita and the Human Development Index. It has maintained an informal economy mainly based on livestock, remittances from Somalis working abroad, and telecommunications. It is a member of the United Nations, the Arab League, African Union, Non-Aligned Movement, East African Community, and the Organisation of Islamic Cooperation.
== Composition == Most hotspot volcanoes are basaltic (e.g., Hawaii, Tahiti). As a result, they are less explosive than subduction zone volcanoes, in which water is trapped under the overriding plate. Where hotspots occur in continental regions, basaltic magma rises through the continental crust, which melts to form rhyolites which can form violent eruptions. For example, the Yellowstone Caldera was formed by some of the most powerful volcanic explosions in geologic history. However, when the rhyolite is completely ejected, it may be followed by eruptions of basaltic magma rising through the same lithospheric fissures (cracks in the lithosphere). An example of this activity is the Ilgachuz Range in British Columbia, which was created by an early complex series of trachyte and rhyolite eruptions, and late extrusion of a sequence of basaltic lava flows. The hotspot hypothesis is now closely linked to the mantle plume hypothesis. The detailed compositional studies now possible on hotspot basalts have allowed linkage of samples over the wider areas often implicate in the later hypothesis, and its seismic imaging developments.
==== Solanezumab ==== Solanezumab, an anti-Aβ mAb, targets the N-terminus of Aβ. In Phase I and Phase II of clinical trials, Solanezumab treatment resulted in cerebrospinal fluid elevation of Aβ, thereby showing a reduced concentration of Aβ plaques. Additionally, there are no associated adverse side effects. Phase III clinical trials of Solanezumab brought about significant reduction in cognitive impairment in patients with mild AD, but not in patients with severe AD. However, Aβ concentration did not significantly change, along with other AD biomarkers, including phospho-tau expression, and hippocampal volume. Phase III clinical trials of Solanezumab failed as it did not show effect on cognitive decline in comparison to placebo.
=== Response from health organizations === The American Cancer Society "has no formal position regarding rBGH". The American Nurses Association supports the development of national and state laws, regulations, and policies that specifically reduce the use of rBGH or rBST in milk and dairy production in the United States.
Sources: en.wikipedia.org
== Further reading == Biochemistry textbook reference, from the NCBI bookshelf – Jeremy M. Berg; John L. Tymoczko; Lubert Stryer (eds.). "18.4. A Proton Gradient Powers the Synthesis of ATP". Biochemistry (5th ed.). W. H. Freeman. Archived from the original on August 3, 2007. A set of experiments aiming to test some tenets of the chemiosmotic theory – Ogawa S, Lee TM (August 1984). "The relation between the internal phosphorylation potential and the proton motive force in mitochondria during ATP synthesis and hydrolysis". The Journal of Biological Chemistry. 259 (16): 10004–10011. doi:10.1016/S0021-9258(18)90918-X. PMID 6469951.
=== Jackie Harris === Marjorie Jacqueline "Jackie" Harris Goldufski is played by Laurie Metcalf. Jackie is Roseanne's younger sister by three years. She is a neurotic but a loving, devoted aunt to her nieces and nephews, and later mother to Andy. Jackie is an intelligent, warm, highly sensitive underachiever with chronic low self-esteem. Roseanne seems to be in charge of Jackie's life, which frequently causes conflict between the two sisters; however, Jackie sometimes enjoys having Roseanne mother her, especially when she feels vulnerable. Like Roseanne, Jackie's relationship with their mother is strained, chafing under Bev's constant criticism and disapproval of her life choices. She is closer to her father, but as his past abusive behavior is revealed in later seasons, Jackie is shown as having coped by using selective denial or justifying his behavior. Jackie's character becomes more animated and colorful as the series progresses. Jackie holds numerous jobs: working in the Wellman Plastics factory for several years until the walkout, then becoming a police officer until being injured on the job, then is a truck driver before finally opening the Lanford Lunch Box with Roseanne and Nancy, and also mother Bev as a fourth partner. In Season 10, Jackie is now a life coach. In The Conners, Jackie, along with Becky, revives the old Lanford Lunch Box when the previous restaurant occupying the space closes, then struggles to keep it afloat during the COVID pandemic, showing her adaptability and perseverance. Jackie often comes up with off-the-wall ideas, but many actually work.
== Medical use == Cyclofenil is used to treat menstrual disturbances and anovulatory infertility caused by insufficiency of the hypothalamic–pituitary–gonadal axis in women. It has also been used to treat menopausal symptoms. The medication is generally used at a dosage of 400 to 600 mg per day.
The Bergmann degradation begins with benzoylation at the alpha-group of a peptide and subsequent conversion to an acyl azide. As in the Curtius rearrangement, the acyl azide, in the presence of benzyl alcohol and heat, rearranges to a highly reactive isocyanate intermediate, releasing nitrogen gas in the process. The isocyanate in turn reacts with benzyl alcohol to form a benzylurethane (also referred to as carboxybenzyl), a compound possessing a carbamate amine protecting group. Subsequent removal of the carbamate protecting group is carried out by catalytic hydrogenation in the presence of hydrochloric acid followed by addition to boiling water, yielding an unstable intermediate that rapidly rearranges to release carbon dioxide, driving the reaction forward. This leads to further rearrangement and subsequent hydrolysis, ultimately resulting in the formation of an aldehyde bearing the next amino acid residue in the sequencing series and the expulsion of the residual peptide in amide form.
Studies in the zebrafish Danio rerio show that TBR1 is highly conserved across species. TBR1 cDNA clones from zebrafish were acquired by screening a zebrafish embryo using a phosphorus labeled probe. The TBR1 found in zebrafish (zf-TBR1) has 83-97% amino acid identity to orthologs in humans (hu-TBR1), xenopus (x-EOMES), and mice (mu-TBR1). The zebrafish TBR1 is only expressed in the forebrain, not in other regions of the zebrafish embryo. The evolution of TBR1 has been studied in amphioxi, also known as lancelets. A T-box-containing cDNA was isolated in the lancelet Branchiostoma belcheri and found to possess a T-domain orthologous to that of the T-Brain subfamily of T-box genes, specifically TBR1. However, lancelets lack a true brain and no TBR1 transcripts were found in the neural tissue of the lancelet. This suggests that the neuronal role of TBR1 evolved in vertebrates after the lancelet lineage had already diverged from that of vertebrates. TBR1 both positively and negatively regulates gene expression in postmitotic neurons.
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.
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.