Everything below concerns methionine sulfoxide. We keep the language plain, cite what the science says, and separate well-supported claims from open questions.
Last reviewed on 2026-03-11. Where a claim depends on a specific study, the study is described rather than over-claimed.
Once dissolved, the peptide is considerably less stable than the solid. Aqueous solutions are usually prepared at neutral to slightly acidic pH, filtered, and divided into single-use aliquots before freezing. Repeated freeze-thaw cycles are a common cause of avoidable loss and are best prevented by never refreezing a thawed aliquot. Adsorption to plastic and glass surfaces can lower the measured concentration of dilute solutions, particularly below roughly 0.1 mg/mL. Buffer choice, salt content, and container material all influence how much peptide remains detectable after storage.
Identity and purity are established with standard peptide methods. Reversed-phase HPLC with ultraviolet detection near 214 nm resolves the parent peak from deletion and truncation byproducts, and reports typically quote a main-peak percentage. Mass spectrometry by electrospray or MALDI-TOF confirms the expected molecular mass, while amino acid analysis or peptide mapping can verify composition when the sequence itself is in question. A certificate of analysis that pairs a chromatogram with a mass spectrum is more informative than a purity figure alone. Counter-ion content and residual solvents are separate specifications and are frequently omitted.
Semax is normally supplied as a lyophilized powder, and that form is the most stable. Suppliers commonly recommend storage at -20 °C in a desiccated container protected from light, with short-term handling at room temperature limited to weighing and transfer. Powder that has absorbed moisture degrades faster, so vials should be warmed to ambient temperature before opening to prevent condensation on the contents. Hygroscopic behavior is typical of short hydrophilic peptides, and humidity control matters more than temperature alone for long-term retention.
Development took place during the 1980s at institutes of the Russian Academy of Sciences, where peptide fragments of ACTH were screened for cognitive and neuroprotective effects. The compound received regulatory approval in Russia as a nasal preparation, marketed for conditions such as ischemic stroke, transient ischemic attacks, and optic nerve disorders. Registration in other countries has not followed. Most published clinical reports originate from a small number of Russian research groups, and independent replication outside that setting remains limited. The regulatory status therefore differs sharply between Russia and the rest of the world.
Laboratory work points toward modulation of neurotrophic signaling, particularly expression of brain-derived neurotrophic factor and nerve growth factor in hippocampal tissue. Studies also describe effects on monoamine turnover, inflammatory mediators, and oxidative markers. These observations come mainly from animal models and cultured cells, so the causal chain in humans is not firmly established. Whether the reported molecular changes translate into measurable clinical benefit is an open question. Reviews generally present the mechanism as plausible rather than demonstrated.
| Property | Value | Notes |
|---|---|---|
| Solid storage temperature | -20 °C or below | Desiccated and protected from light |
| Solution storage temperature | -80 °C as single-use aliquots | Avoid repeated freeze-thaw cycles |
| Purity assessment method | RP-HPLC, around 214 nm | Reported as main-peak area percent |
| Identity confirmation method | ESI-MS or MALDI-TOF | Measured mass compared with calculated mass |
| Common synonyms | ACTH(4-10) analog; Met-Glu-His-Phe-Pro-Gly-Pro | Also written as Semaxum in some sources |
Published research covers ischemic stroke, traumatic brain injury, cognitive impairment, optic nerve conditions and attention-related measures. Much of the human evidence comes from small trials conducted in one country, which limits how far the results generalize. Animal models supply the larger share of the data, and effects seen in rodents do not transfer automatically to people. Reviews have noted that methodological reporting is often incomplete, making it difficult to pool results or compare treatment schedules across studies.
Pharmacokinetic accounts emphasize rapid breakdown. After intravenous dosing the intact peptide disappears from blood within minutes, and nasal delivery produces low but measurable concentrations. Metabolites rather than the parent molecule may account for part of the observed activity, although the relative contribution is unresolved. Dosing in the literature varies widely and no optimal schedule has been agreed. These gaps are regularly cited as a reason the findings have not produced broad clinical adoption beyond the original research setting.
Proposed mechanisms center on neurotrophic signaling rather than on classical melanocortin receptor activation. Rodent experiments have reported shifts in the expression of brain-derived neurotrophic factor and nerve growth factor after administration, together with changes in the associated receptor systems. Several authors argue that the peptide acts largely through its degradation products and their interaction with peptidergic pathways, but this remains a hypothesis rather than a settled finding. No single molecular target has been identified in a way that the field broadly accepts.
Later generations of the molecule include an N-acetylated form and an amidated form, both marketed online alongside the parent peptide. These variants differ in terminal chemistry and stability, and they are frequently discussed in the same breath even though they have not been compared in controlled trials. Supply outside formal healthcare systems comes largely from laboratories that synthesize peptides to order. Purity and identity of these materials vary widely, and no single body oversees the international trade.
Semax is a synthetic heptapeptide developed in the Soviet Union during the 1980s by researchers at the Institute of Molecular Genetics in Moscow. It was designed as a truncated analog of adrenocorticotropic hormone, retaining only the fragment spanning residues four through ten. Investigators sought a peptide that would preserve the cognitive effects associated with ACTH while eliminating the hormonal stimulation of the adrenal cortex. The compound entered clinical use in Russia during the following decade.
Russian regulatory authorities approved the peptide for nasal administration, and it remains listed in the national pharmacopoeia under several trade names. Documented indications include acute ischemic stroke, transient ischemic attacks, traumatic brain injury, and certain ophthalmological and neurological conditions. Physicians also prescribe it for cognitive complaints in older patients, although the evidence base for that use is thinner. Outside Russia and a few neighboring states, the substance is not an approved medicine and is sold instead as a research chemical.
Dissolution is normally performed in water, phosphate-buffered saline, or normal saline, since the peptide is freely soluble in aqueous media and is rarely handled with strong organic solvents. Solution pH should be kept near neutral, because extreme acidity or alkalinity accelerates backbone hydrolysis and encourages oxidation of the methionine side chain. Once dissolved, the material is less stable than the dry powder and is commonly divided into single-use portions and frozen. Buffers containing primary amines, such as Tris, are often avoided because of possible side reactions.
Purity assessment relies mainly on reversed-phase high-performance liquid chromatography, which separates the target heptapeptide from truncated sequences, deletion analogues, and oxidised forms. Mass spectrometry, usually coupled to liquid chromatography, confirms identity through the expected molecular ion and reveals modifications such as methionine sulfoxide formation. Amino acid analysis can verify composition, and tandem mass spectrometry supports sequence confirmation. Ultraviolet detection near 254 to 280 nanometres is convenient because the phenylalanine and histidine residues absorb in that region. Nuclear magnetic resonance is rarely used for routine release testing.
Semax is a synthetic heptapeptide with the sequence Met-Glu-His-Phe-Pro-Gly-Pro. It was derived from the ACTH(4-10) fragment, a short segment of adrenocorticotropic hormone that lacks the hormonal activity associated with the full-length peptide. Researchers at the Institute of Molecular Genetics in Moscow developed the compound during the 1980s. It has been registered as a pharmaceutical product in Russia and several neighbouring countries, where it is supplied as a nasal solution, and it is also sold internationally as a research chemical.
The proposed mechanism centres on neurotrophic signalling rather than direct receptor activation. Semax is reported to increase expression of brain-derived neurotrophic factor and nerve growth factor in several brain regions, and to shift the balance between excitatory and inhibitory neurotransmitter systems. Interaction with melanocortin receptors has been suggested because of the parent ACTH fragment. Many of these findings come from rodent studies, and the extent to which they translate to human physiology remains an open question.
== Biological functions == Like most siderophores, pyoverdine is synthesized and secreted into the environment when the microorganism that produces it detects that intracellular iron concentrations have fallen below a preset threshold. Although iron is the fourth-most abundant element in the Earth's crust, solubility of biologically relevant iron compounds is exceedingly low, and is generally insufficient for the needs of most (but not all) microorganisms. Siderophores, which are typically quite soluble and have exceptionally high avidity for iron (III) (the avidity of some siderophores for iron exceeds 1040 M-1 and many of the strongest avidities ever observed in nature are exhibited by siderophores for iron), help increase bioavailability of iron by pulling it into aqueous solution. In addition to this role, pyoverdine has a number of other functions, including regulating virulence, limiting the growth of other bacterial species (and serving as a sort of antimicrobial) by limiting iron availability, and sequestering other metals and preventing their toxicity.
Elevated ITGA1 expression correlates with activation of survival pathways and is regulated through a non-coding RNA mechanism involving hsa_circ_0110757, which increases ITGA1 expression by suppressing hsa-miR-1298-5p.
== Diagnosis == VWD is diagnosed by a combination of a personal or family history of excessive bleeding plus lab tests showing abnormalities in either the amount or function of vWF or factor VIII. Basic tests performed in any patient with bleeding problems are a complete blood count, activated partial thromboplastin time (aPTT), prothrombin time with an International Normalized Ratio, thrombin time, and fibrinogen level. People with abnormal tests typically undergo further testing for hemophilias. Other coagulation factor assays may be performed depending on the results of a coagulation screen. People with von Willebrand disease typically display a normal prothrombin time and a variable prolongation of aPTT, depending on whether sufficient VWF is available to perform its carrier function for factor VIII. When VWD is suspected, blood plasma of a patient must be investigated for quantitative and qualitative deficiencies of VWF. This is achieved by measuring the amount of VWF in a VWF antigen assay and the functionality of VWF with a glycoprotein (GP)Ib binding assay, VWF antibody assay, or a ristocetin cofactor activity (RiCof) assay. Factor VIII levels are also performed because factor VIII is bound to VWF which protects the factor VIII from rapid breakdown within the blood. Deficiency of VWF can then lead to a reduction in factor VIII levels, which explains the elevation in PTT.
Sources: en.wikipedia.org
Another Communist, Li Jingxuan, became his secretary-general. Under Liu Yuan'an's influence, Liu Wenhui supposedly expressed interest in inviting the prominent communist Wu Yuzhang to head the Chengdu University and funded progressive newspapers. Liu also asked his communist advisor to send political workers for Liu Wenhui's army. Peng Dixian and Shu Guofan's 1990 biography of Liu, written in the People's Republic by communist-aligned authors, casts these instances as evidence of his "inclinations towards revolution" but noted that these progressive leanings were shallow. In August 1926, Liu Wenhui and Liu Chengxun jointly issued a circular telegram denouncing Wu Peifu, accusing the Beiyang warlord of bringing chaos to Sichuan. This signaled their alignment with the Nationalist cause. In December 1926, the Northern Expedition captured Wuhan, and Liu sent a delegation under Zhang Zhihe [zh] to seek recognition from the new Nationalist government. He joined the Kuomintang and was appointed the commander of the 24th Army of the National Revolutionary Army. After Liu's appointment as commander of the 24th Army, he moved to Chengdu, leaving the defense of Yibin to Tan Xiaolou (覃筱楼), a former bandit leader Liu had recruited. Here, he joined Deng Xihou and Tian Songyao, who had already established themselves in the city. All three were classmates from their Baoding days and ruled as a united front in public, but privately schemed to expand their individual power.
Since biodegradability is an important characteristic of nanogels, these hydrogels are typically composed of natural or degradable synthetic polymers. Polysaccharides and proteins largely dominate the natural forms of polymers used to synthesize nanogels. Due to the use of thiolated polysaccharides (thiomers) such as thiolated chitosan or thiolated hyaluronic acid nanogels can be stabilized via intra- and interchain disulfide bonding. Advantages of natural polymer-based nanogels include biocompatibility and degradability by cellular mechanisms in vivo. Natural polymers also tend to be nontoxic and bioactive in which they are more likely to induce biological cues that govern various aspects of cellular behavior. However, natural-based polymers can still cause an immune response and possess other disadvantages such as variable degradation rates and heterogeneous structures. Conversely, synthetic-based polymers have more defined structures, increased stability, and controlled degradation rates. In comparison to natural-based polymers, synthetic polymers lack biological cues that may be necessary for specific therapeutic applications. Given that natural and synthetic polymers are defined by their own set of advantages and disadvantages, an ongoing area of research aims to create composite hydrogels for nanogel synthesis that combines synthetic and natural polymers to leverage the benefits of both in one nanogel formulation.
While the exact end date of the Cold War is debated among historians, it is generally agreed upon that the implementation of nuclear and conventional arms control agreements, the withdrawal of Soviet military forces from Afghanistan and Eastern Europe, and the resultant collapse of the Soviet Union marked the end of the Cold War. Scholars remain divided over the underlying causes, with materialist accounts emphasizing Soviet economic decline and ideational accounts stressing the personal worldviews of Gorbachev and Reagan coupled with the broader appeal of the Western European model.
=== Management === No agents of biological pest control are used against the lesser mealworm. The fungus Beauveria bassiana is an arthropod pathogen that may prove useful. Some protozoa and spider species are known natural predators. Control is usually attempted with carbaryl insecticide in the form of powder, liquid, and bait. Thiamethoxam and 9-Tricosene used in conjunction have been shown to be successful in poultry houses. Pyrethroids and boric acid are used. True outbreaks are often uncontrollable and some populations of the beetle have shown resistance to various compounds. Resistance is more common on farms that have been chemically treated for many years. Insecticides are not ideal because they contaminate the poultry and they are not effective on the pest when it burrows out of reach. Proper maintenance of poultry housing usually keeps the beetle under control, as it propagates in accumulated litter and droppings.
Sources: en.wikipedia.org
tetramer A molecular aggregate consisting of four subunits. The term is often used to refer to protein complexes composed of four proteins, e.g. haemoglobin, or to individual proteins composed of four polypeptides. Compare monomer, dimer, and trimer.
Single-walled nanotubes are likely candidates for miniaturizing electronics. The most basic building block of these systems is an electric wire, and SWNTs with diameters of an order of a nanometre can be excellent conductors. One useful application of SWNTs is in the development of the first intermolecular field-effect transistors (FET). The first intermolecular logic gate using SWCNT FETs was made in 2001. A logic gate requires both a p-FET and an n-FET. Because SWNTs are p-FETs when exposed to oxygen and n-FETs otherwise, it is possible to expose half of an SWNT to oxygen and protect the other half from it. The resulting SWNT acts as a not logic gate with both p- and n-type FETs in the same molecule. Large quantities of pure CNTs can be made into a freestanding sheet or film by surface-engineered tape-casting (SETC) fabrication technique which is a scalable method to fabricate flexible and foldable sheets with superior properties. Another reported form factor is CNT fiber (a.k.a. filament) by wet spinning. The fiber is either directly spun from the synthesis pot or spun from pre-made dissolved CNTs. Individual fibers can be turned into a yarn. Apart from its strength and flexibility, the main advantage is making an electrically conducting yarn. The electronic properties of individual CNT fibers (i.e. bundle of individual CNT) are governed by the two-dimensional structure of CNTs. The fibers were measured to have a resistivity only one order of magnitude higher than metallic conductors at 300 K (27 °C; 80 °F).
==== Officer of the Order of the British Empire (OBE) ==== Military Commander Trefor Morgan Fox, Royal Navy, C037045S. Commander Christopher Robert Hollingworth, Royal Navy, C041543F. Colonel Andrew Glenn David Lock, Royal Marines, N029023U. Commander Lucy Jane Ottley, Royal Navy, V030919T. Commander Ian Hayden Richardson, Royal Navy, C038366T. Commander Jamie Duncan Wells, Royal Navy, C039514F. Captain Allan Thomas Youp, Royal Navy, C038889U. Lieutenant Colonel Nicholas Paul Andrew, Royal Regiment of Artillery, 537949. Lieutenant Colonel Tracy-Louise Appleyard, Royal Army Medical Corps, 540495. Colonel Edward Hugh James Carter, 532335. Lieutenant Colonel Ewan Christian Noble Harris, The Royal Welsh, 545550. Lieutenant Colonel Timothy Matthew Holmes, Corps of Royal Electrical and Mechanical Engineers, 546527. Colonel Matthew Gordon Timothy Lewis, 554319. Lieutenant Colonel (now Acting Colonel) John Andrew Lyons, Royal Corps of Signals, 549561. Lieutenant Colonel Craig David Pope, Royal Army Medical Corps, 549180. Colonel Nigel Offley Crewe-Read, , 545207. Colonel Thomas Woolley, 551152. Colonel Nicholas George Charles Yardley, 544447. Wing Commander Erica Jane Ferguson, Royal Air Force, 2629012K. Wing Commander Matthew Elfed Lewis, Royal Air Force, 5208143G. Wing Commander Stephen McCleery, Royal Air Force, 2635078L. Wing Commander Alison Morton, Royal Air Force, W996632T. Air Commodore Patrick James Shea-Simonds, Royal Air Force, 5208323H. Group Captain Paul Andrew Weaver Smith, Royal Air Force, 8024057B.
JEOL, Ltd. (日本電子, Nihon Denshi Kabushiki-kaisha; Nihon meaning Japan and Denshi meaning electron) is a major developer and manufacturer of electron microscopes and other scientific instruments, industrial equipment and medical equipment. Its headquarters are in Tokyo, Japan, with 25 domestic and foreign subsidiaries and associated companies as of 2014. It is listed in the top ten businesses worldwide for analytical laboratory instrument manufacturing. It has been included in the Activest Lux Nanotech Mutual Fund and the WestLB Nanotech Fund.
An ACS program chair, Gopal Coimbatore, said that without a proper forum the matter would never be discussed and, "with the world facing an energy crisis, it is worth exploring all possibilities." On 22–25 March 2009, the American Chemical Society meeting included a four-day symposium in conjunction with the 20th anniversary of the announcement of cold fusion. Researchers working at the U.S. Navy's Space and Naval Warfare Systems Center (SPAWAR) reported detection of energetic neutrons using a heavy water electrolysis setup and a CR-39 detector, a result previously published in Naturwissenschaften. The authors claim that these neutrons are indicative of nuclear reactions. Without quantitative analysis of the number, energy, and timing of the neutrons and exclusion of other potential sources, this interpretation is unlikely to find acceptance by the wider scientific community.
Sources: en.wikipedia.org
Each freeze-thaw cycle can degrade a fraction of the peptide and promote aggregation. Dividing a stock solution into single-use volumes removes repeated cycling as a variable. It also limits the time a thawed solution spends at room temperature.
A high main-peak percentage says little about identity, counter-ion content, or residual solvents. It also does not distinguish an isomer or a closely eluting analog. Mass confirmation and the accompanying documentation cover those gaps.
Salt form changes mass, solubility, and hygroscopicity, and acetate and trifluoroacetate salts behave differently in solution. Storage guidance still centers on -20 °C for powder and lower temperatures for solutions. The certificate should state which salt is present.
Semax is a synthetic seven-amino-acid peptide derived from a fragment of corticotropin. It is used in Russia as a nasal preparation, while elsewhere it is studied as a research compound. It is not approved as a medicine in most countries.