lyophilized powder raises a handful of sensible questions. This page answers them in order, starting with the fundamentals and moving to applications.
This page was last updated on 2026-02-28 and is reviewed periodically as new material appears.
Semax is a synthetic heptapeptide with the sequence Met-Glu-His-Phe-Pro-Gly-Pro. It corresponds to the ACTH(4-7) fragment extended at the C-terminus by a Pro-Gly-Pro tripeptide, an addition intended to slow enzymatic breakdown. The molecular formula is C37H51N9O10S and the molecular mass is approximately 814 daltons. In the literature it is often described as an ACTH(4-10) analog, although that label reflects a naming convention as much as a precise structural relationship. The compound was developed in Russia and remains most closely associated with that research tradition.
Laboratory descriptions of the material are consistent across suppliers. It appears as a white to off-white lyophilized powder that dissolves readily in water and in polar organic solvents such as dimethyl sulfoxide. Aqueous solutions are clear and colorless at low concentrations. Because the peptide contains methionine, oxidation at the sulfur atom is a recognized degradation pathway, and handling notes usually call for protected, desiccated storage. Reported purity for research-grade lots is generally above 95 percent as measured by reversed-phase high-performance liquid chromatography.
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.
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.
| Property | Value | Notes |
|---|---|---|
| Molecular formula | C37H51N9O10S | Contains one methionine sulfur atom |
| Molecular mass | Approximately 814 Da | Consistent with a seven-residue peptide |
| Appearance | White to off-white powder | Typical lyophilized form |
| Solubility | Freely soluble in water | Also soluble in dimethyl sulfoxide |
| Typical storage | -20 °C, desiccated | Limits methionine oxidation |
Regulatory status varies sharply by country. Semax is registered for medical use in Russia, where it appears in formularies as a nasal solution, and it also holds registration in a small number of neighbouring states. It has no approval from the United States Food and Drug Administration or the European Medicines Agency, and it is not a scheduled controlled substance in most jurisdictions. Elsewhere it circulates mainly as laboratory material, so purity documentation comes from suppliers rather than from a national pharmacopoeia.
Semax is a synthetic peptide created in the Soviet Union during the early 1980s by researchers working in Moscow. It was built from the short adrenocorticotropic hormone fragment known as ACTH(4-10), and the chain was then extended with three additional amino acids. The resulting molecule was named semax and entered clinical use in Russia in 1994. It is generally described as a nootropic and neuroprotective agent rather than as a hormone analogue.
The parent fragment ACTH(4-10) carries the sequence Met-Glu-His-Phe-Arg-Trp-Gly. Semax replaces the arginine and tryptophan positions with a proline-glycine-proline tail, giving Met-Glu-His-Phe-Pro-Gly-Pro. That change removes residues associated with adrenal stimulation, so the peptide does not drive cortisol release the way full ACTH does. This distinction shapes how the compound is grouped in the literature, where it sits with neuropeptides and peptide neuromodulators rather than with corticosteroids.
Aerotolerant anaerobes use fermentation to produce ATP. They do not use oxygen, but they can protect themselves from reactive oxygen molecules. In contrast, obligate anaerobes can be harmed by reactive oxygen molecules. There are three categories of anaerobes. Where obligate aerobes require oxygen to grow, obligate anaerobes are damaged by oxygen, aerotolerant organisms cannot use oxygen but tolerate its presence, and facultative anaerobes use oxygen if it is present but can grow without it. Most aerotolerant anaerobes have superoxide dismutase and (non-catalase) peroxidase but do not have catalase. More specifically, they may use a NADH oxidase/NADH peroxidase (NOX/NPR) system or a glutathione peroxidase system. An example of an aerotolerant anaerobe is Cutibacterium acnes.
==== Psychosis ==== Cocaine has a similar potential to induce temporary psychosis with more than half of cocaine abusers reporting at least some psychotic symptoms at some point. Typical symptoms include paranoid delusions that they are being followed and that their drug use is being watched, accompanied by hallucinations that support the delusional beliefs. Delusional parasitosis with formication ('cocaine bugs') is also a fairly common symptom. Cocaine-induced psychosis shows sensitization toward the psychotic effects of the drug. This means that psychosis becomes more severe with repeated intermittent use.
Interferons were first described in 1957 by Alick Isaacs and Jean Lindenmann at the National Institute for Medical Research in London; the discovery was a result of their studies of viral interference. Viral interference refers to the inhibition of virus growth caused by previous exposure of cells to an active or a heat-inactivated virus. Isaacs and Lindenmann were working with a system that involved the inhibition of the growth of live influenza virus in chicken embryo chorioallantoic membranes by heat-inactivated influenza virus. Their experiments revealed that this interference was mediated by a protein released by cells in the heat-inactivated influenza virus-treated membranes. They published their results in 1957 naming the antiviral factor they had discovered interferon. The findings of Isaacs and Lindenmann have been widely confirmed and corroborated in the literature. Furthermore, others may have made observations on interferons before the 1957 publication of Isaacs and Lindenmann. For example, during research to produce a more efficient vaccine for smallpox, Yasu-ichi Nagano and Yasuhiko Kojima—two Japanese virologists working at the Institute for Infectious Diseases at the University of Tokyo—noticed inhibition of viral growth in an area of rabbit-skin or testis previously inoculated with UV-inactivated virus. They hypothesised that some "viral inhibitory factor" was present in the tissues infected with virus and attempted to isolate and characterize this factor from tissue homogenates.
Symptoms of meprobamate overdose include drowsiness, headache, sluggishness, unresponsiveness, or coma; loss of muscle control; severe impairment or cessation of breathing; or shock. Death has been reported with ingestion of as little as 12 g of meprobamate and survival with as much as 40 g. In an overdose, meprobamate tablets may form a gastric bezoar, requiring physical removal of the undissolved mass of tablets through an endoscope; therefore, administration of activated charcoal should be considered even after 4 or more hours or if levels are rising.
Sources: en.wikipedia.org
Using fundamental principles established by IUPAC, the delta (Δ) system for lipid notation was developed by researchers within the mid-20th century, to address the need for distinction between fatty acids with the same acyl chain length but different double bond positions. Thus, the Δ system defines the position of double bonds by virtue of the carboxyl (–COOH) carbon using the general formula: C:DΔy where C is the total number of carbons, D is the number of double bonds, and Δy indicates the position of each double bond, counting from the –COOH end of the fatty acid. Unlike the omega nomenclature system, each double bond of the fatty acid must be described in the delta system.
=== Avionics === Pizhma-1 navigational system with OMEGA inputs. GPS transceivers and a TCAS fitted retroactively during the 1990s. Pizhma-1 can be used throughout the flight from departure terminal area to landing and taxi to stand. Pizhma-1 has full-time roll and yaw dampers. Airfield approach aids enable instrument landing system-coupled approaches to ICAO Category II weather minima. Other radio aids include VOR and DME receivers, a weather radar, and Warsaw Pact identification aids. Cockpit voice recorders and flight data recorders standard. Four GT-40PCh6 engine generators generate energy from the Kuznetsov NK-86. The APU or ground sources supply 200/115 V, 400 Hz current to the primary system or two secondary systems (36 V/400 Hz AC and 27 V DC). Recipients include high-lift devices, tailplane trim, deicing, galley lift (elevator) and interior services.
=== Glycosyltransferase === OGT catalyzes the addition of a single N-acetylglucosamine through an O-glycosidic linkage to serine or threonine and an S-glycosidic linkage to cysteine residues of nucleocytoplasmic proteins. Since both phosphorylation and O-GlcNAcylation compete for similar serine or threonine residues, the two processes may compete for sites, or they may alter the substrate specificity of nearby sites by steric or electrostatic effects. Two transcript variants encoding cytoplasmic and mitochondrial isoforms have been found for this gene. OGT glycosylates many proteins including: Histone H2B, AKT1, PFKL, KMT2E/MLL5, MAPT/TAU, Host cell factor C1, and SIN3A. O-GlcNAc transferase is a part of a host of biological functions within the human body. OGT is involved in the resistance of insulin in muscle cells and adipocytes by inhibiting the Threonine 308 phosphorylation of AKT1, increasing the rate of IRS1 phosphorylation (at serine 307 and serine 632/635), reducing insulin signaling, and glycosylating components of insulin signals. Additionally, O-GlcNAc transferase catalyzes intracellular glycosylation of serine and threonine residues with the addition of N-acetylglucosamine. Studies show that OGT alleles are vital for embryogenesis, and that OGT is necessary for intracellular glycosylation and embryonic stem cell vitality. O-GlcNAc transferase also catalyzes the posttranslational modification that modifies transcription factors and RNA polymerase II, however the specific function of this modification is mostly unknown.
Hydroxyurea has been prepared in many different ways since its initial synthesis in 1869. The original synthesis by Dresler and Stein was based around the reaction of hydroxylamine hydrochloride and potassium cyanate. Hydroxyurea lay dormant for more than fifty years until it was studied as part of an investigation into the toxicity of protein metabolites. Due to its chemical properties hydroxyurea was explored as an antisickling agent in the treatment of hematological conditions. One common mechanism for synthesizing hydroxyurea is by the reaction of calcium cyanate with hydroxylamine nitrate in absolute ethanol and by the reaction of a cyanate salt and hydroxylamine hydrochloride in aqueous solution. Hydroxyurea has also been prepared by converting a quaternary ammonium anion exchange resin from the chloride form to the cyanate form with sodium cyanate and reacting the resin in the cyanate form with hydroxylamine hydrochloride. This method of hydroxyurea synthesis was patented by Hussain et al. (2015).
"Crystallographic analysis of a new psychrophilic haloalkane dehalogenases: DpcA from Psychrobacter cryohalolentis K5 and DmxA from Marinobacter sp. ELB17". Acta Crystallogr. F69 (6): 683–688. doi:10.1107/S1744309113012979. PMC 3668595. PMID 23722854.
Sources: en.wikipedia.org
It is registered as a pharmaceutical product in Russia, where it is typically supplied as a nasal solution. In most other countries it is not an approved drug and is traded as a research chemical instead. Approval status depends entirely on the jurisdiction involved.
Most published work uses intranasal administration, matching the route of the registered Russian formulation. Some animal experiments use intravenous or intraperitoneal injection. The route matters because the intact peptide is cleared rapidly from blood, so exposure differs between methods.
A purity value describes the share of the powder accounted for by the target peptide, usually by high-performance liquid chromatography. It does not confirm that the sequence is correct, which requires mass spectrometry or amino acid analysis. Purity and identity are separate checks.
It originated at the Institute of Molecular Genetics in Moscow during the 1980s. The work was carried out by a Russian research group that specialized in peptide neuropharmacology.