Everything below concerns freeze-thaw. We keep the language plain, cite what the science says, and separate well-supported claims from open questions.
Updated 2025-11-06. Numbers and descriptions here follow the published literature rather than marketing material.
Verification of a supplied batch generally combines a certificate of analysis with independent testing, because certificates are self-reported documents. A typical package includes a chromatographic trace, a mass spectrum, and a stated water or counter-ion content. Batch-to-batch consistency matters more than a single purity figure when results are compared across experiments. No single mandatory standard governs research-grade peptide release, so laboratories are expected to define their own acceptance criteria. Residual trifluoroacetate from purification is a frequently overlooked counter-ion.
Lyophilized material is chemically stable for extended periods when kept dry, cold, and protected from light. The powder is hygroscopic, so vials should be warmed to room temperature before opening to reduce condensation on the contents. Once dissolved, the peptide is far less stable because peptide bonds are susceptible to hydrolysis and the methionine residue can oxidize. Solutions are typically aliquoted and held at 2-8 °C for short intervals or frozen for longer ones, and repeated freeze-thaw cycles should be avoided.
Regulatory status differs sharply between jurisdictions. In Russia the peptide is registered as a prescription nasal preparation, while agencies such as the United States Food and Drug Administration have not approved it for any indication. Products sold elsewhere are typically labeled for laboratory research only, and such labels shift responsibility for safe handling to the purchaser. Because the same name covers pharmaceutical-grade nasal drops and bulk research powder, identity and purity documentation becomes the main practical concern when comparing sources.
Semax is a synthetic seven-amino-acid peptide whose sequence extends the ACTH(4-10) fragment with a C-terminal proline-glycine-proline tripeptide. The commonly cited sequence is Met-Glu-His-Phe-Pro-Gly-Pro, giving a molecular formula near C37H51N9O10S and a molecular weight close to 813.9 g/mol. It belongs to the broader class of synthetic ACTH fragments studied for central nervous system effects rather than for adrenal steroid stimulation. In practice the material appears as a lyophilized white powder for laboratory work or as a dilute saline solution in clinical settings.
Development is attributed to researchers at the Institute of Molecular Genetics in Moscow during the early 1980s, building on earlier Soviet work with ACTH fragments. Russian regulatory approval followed for intranasal use, and the compound has remained commercially available there for decades. Most published human data originate from Russian and, later, some Eastern European clinical reports, which are not always accessible in English translation. Outside that region the material is generally handled as a research chemical rather than a licensed medicine.
| Property | Value | Notes |
|---|---|---|
| Typical purity | 95% or higher | By reversed-phase HPLC area |
| Identity method | Electrospray mass spectrometry | Confirms molecular mass |
| Purity method | Reversed-phase HPLC | Detection near 214 nm |
| Primary degradation | Methionine oxidation | Sulfoxide product, +16 Da |
| Solution storage | 2-8 °C, short term | Aliquot to avoid freeze-thaw |
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.
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.
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.
Scientific literature on semax is unevenly distributed. A substantial share of published work originates from a small number of laboratories in Russia, while independent replication elsewhere is limited. Human data consist mostly of small trials with short follow-up, and several reported outcomes rely on subjective rating scales. Questions about how much intact peptide reaches the central nervous system after nasal administration, and how long it persists there, are still unresolved. The compound is best described as an active research subject rather than a settled pharmacological agent.
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.
Quality documentation for research-grade peptide usually includes a certificate of analysis stating purity, identity, and residual counterion content. Batch-to-batch variation in purity and salt form is a recognized issue, and comparisons across suppliers require attention to the exact counterion, for example acetate versus trifluoroacetate. Sequence verification by tandem mass spectrometry provides stronger evidence than a single mass measurement. For any study reporting biological results, the analytical method and the measured purity should be stated explicitly. Independent verification of supplier claims is considered good practice.
Semax is supplied as a lyophilized powder that appears white to off-white. It dissolves readily in water, phosphate-buffered saline, and other aqueous media, which simplifies preparation of working solutions for laboratory use. The nasal products registered in Russia are dilute aqueous solutions, typically around 0.1 percent peptide by weight. Organic solvents are rarely necessary and can complicate handling. Because the peptide is hygroscopic, weighing should be performed quickly and with minimal exposure to ambient humidity.
Ovothiol A (N1-methyl-4-mercaptohistidine) is a highly reducing antioxidant which accumulates to very high levels in the eggs of certain marine invertebrates, including sea urchins, scallops and starfish, where it acts to quench the hydrogen peroxide released during fertilization. This thiol-type antioxidant is also found in some human pathogens such as Trypanosoma cruzi and Leishmania donovani. It is synthesized by the addition and oxidation of cysteine to histidine by 5-histidylcysteine sulfoxide synthase, followed by methylation and further reduction.
Macallum, A.B. & Collop (sic), J.B. (1914), "A New Substance in Nerve Cells" (read: Monday, 15 September 1913), Report of the Eighty-Third Meeting of the British Association for the Advancement of Science: Birmingham: 1913: September 10-17 (Physiology Section), pp. 673–674. Marier, Virginie & Piper, Tina (2010), "Early Twentieth-Century Canadian Medical Patent Law in Practice: James Bertram Collip and the Discovery of Emenin", University of Toronto Law Journal, Vol.60, No.3, (Summer 2010), pp. 855-892. US patent no.1,469,994 (held by "Frederick G. Banting and Charles Herbert Best, of Toronto, Ontario, and James Bertram Collip of Edmonton, Alberta, Canada"), (filed: 12 January 1923), (patented: 9 October 1923), for "Extract Obtainable from the Mammalian Pancreas or from the Related Glands in Fishes, Useful in the Treatment of Diabetes Mellitus, and a Method of Preparing it".
Environmental health laboratories are governmental laboratories that conduct testing to protect human health and the environment. In some states, a single laboratory acts as both the environmental and the public health laboratory. In other states, the environmental laboratory is part of the department of environmental quality or natural resources while the public health laboratory is part of the health department. Environmental health laboratories help to identify contaminants by conducting regular testing of water, air, soil, food and other media to ensure that populations are not being exposed to unhealthy levels of contamination. APHL supports these laboratories by coordinating a response to environmental health issues. They assist in providing information and training to the scientists working in the labs, and serve as a link between member laboratories and federal agencies, including Centers for Disease Control and Prevention's (CDC) National Center for Environmental Health and the US Environmental Protection Agency.
At 3%, calcium is the fifth most abundant element in the Earth's crust, and the third most abundant metal behind aluminium and iron. It is also the fourth most abundant element in the lunar highlands. Sedimentary calcium carbonate deposits pervade the Earth's surface as fossilised remains of past marine life; they occur in two forms, the rhombohedral calcite (more common) and the orthorhombic aragonite (forming in more temperate seas). Minerals of the first type include limestone, dolomite, marble, chalk, and Iceland spar; aragonite beds make up the Bahamas, the Florida Keys, and the Red Sea basins. Corals, sea shells, and pearls are mostly made up of calcium carbonate. Among the other important minerals of calcium are gypsum (CaSO4·2H2O), anhydrite (CaSO4), fluorite (CaF2), and apatite ([Ca5(PO4)3X], X = OH, Cl, or F) The major producers of calcium are China (about 10000 to 12000 tonnes per year), Russia (about 6000 to 8000 tonnes per year), and the United States (about 2000 to 4000 tonnes per year). Canada and France are among the minor producers. In 2005, about 24000 tonnes of calcium were produced; about half of the world's extracted calcium is used by the United States, with about 80% of the output used each year. In Russia and China, Davy's method of electrolysis is still used, but is instead applied to molten calcium chloride. Since calcium is less reactive than strontium or barium, the oxide–nitride coating that results in air is stable and lathe machining and other standard metallurgical techniques are suitable for calcium. In the U.S.
He was later threatened by the FDA with dismissal. By that time, the drug had been linked to 63 liver-failure deaths and had generated sales of more than $2.1 billion for Warner-Lambert. The drug cost $1,400 a year per patient in 1998. Pfizer, which had acquired Warner-Lambert in February 2000, reported the withdrawal of Rezulin cost $136 million.
Sources: en.wikipedia.org
=== 13-31 August 2008 === An anonymous U.S. functionary said: "Saakashvili had always told us he could not stand by while Georgian villages were being shelled, and we always knew this was a point of pressure. We always told him that he should not give in to the kind of provocations we knew the Russians were capable of." In August 2008, Modest Kolerov, former head of the Department for international and cultural ties with foreign countries of the President's Office, admitted that the Kremlin had "a clear plan of action in the case of a conflict", and "the expediency with which the military operation was executed confirms that." Robert Gates, United States Secretary of Defense, said on August 14 that there had been clashes with the South Ossetian forces each August since 2004, but "This year it escalated very quickly and it seemed to me that Russians were prepared to take advantage of an opportunity and did so very aggressively." Zbigniew Brzezinski compared Russia's attack on Georgia to the Soviet attack on Finland and wrote that "Moscow was waiting for such an act to provide a pretext for the use of force." He suggested that Russia could attack Ukraine and other post-Soviet countries were not safe. Ralph Peters, a former military intelligence analyst, and several western diplomats (a western diplomat with contacts with the Georgians and a western mediator acquainted with Saakashvili) said that it was Russia who was provoking Georgia. It was reported that the United States had prevented Saakashvili from taking military action in Abkhazia in early May 2008.
relaxation of muscle spasms prevention and retardation of disuse atrophy increase of local blood circulation muscle rehabilitation and re-education electrical muscle stimulation maintaining and increasing range of motion management of chronic and intractable pain including diabetic neuropathy acute post-traumatic and post-surgical pain post-surgical stimulation of muscles to prevent venous thrombosis wound healing drug delivery There is limited evidence supporting electrotherapy, specifically in treating musculoskeletal, osteoarthritis, fibromyalgia, neck pain, lumbopelvic pain, and ulcer conditions. Some of the treatment effectiveness mechanisms are little understood. The natural neurostimulation hypothesis explains the therapeutic effect by the fact that energy stimuli induce mitochondrial stress and microvascular vasodilation. Since healthy neurostimulation should emulate the physical characteristics of a mother's care for her fetus during pregnancy scaled to the treatment parameters of the specific patient, but many techniques of electrotherapy do not consider this, the hypothesis claims that their effectiveness and some practices associated with their use are still anecdotal.
==== Protein-based adhesives ==== Protein-based adhesives are less prevalent and typically used to consolidate painted textiles or multi-media objects, of which fabric is one component. They include isinglass, gelatin, and animal glues.
== Bacterial short-chain fatty acids == Certain bacteria in the gastrointestinal tract ferment fecal fiber into SC-FAs and excrete them as waste products. The excreted SC-FAs enter the gastrointestinal walls, diffuse into the portal venous system, and ultimately flow into the systemic circulation. During this passage, they can activate the FFAR3 on cells in the intestinal wall as well as throughout the body. This activation may: suppress the appetite for food and thereby reduce overeating and the development of obesity; inhibit the liver's accumulation of fatty acids and thereby the development of fatty liver diseases; decrease blood pressure and thereby the development of hypertension and hypertension-related cardiac diseases; modulate insulin secretion and thereby the development and/or symptoms of type 2 diabetes; reduce heart rate and blood plasma norepinephrine levels and thereby lower total body energy expenditures; and suppress or delay the development of allergic asthma. The specific types of bacteria in the intestines can be modified to increase the number which make SC-FAs by using foods that stimulate the growth of these bacteria (i.e., prebiotics), preparations of SC-FA-producing bacteria (i.e., probiotics), or both methods (see synbiotics).
== Chemistry literature == Scientific literature Scientific journal Academic journal List of important publications in chemistry List of scientific journals in chemistry List of science magazines Scientific American
Sources: en.wikipedia.org
== V == Lauri Vaska (1925–2015), Estonian/American chemist Louis Nicolas Vauquelin (1763–1829), French pharmacist and chemist, discovered the elements beryllium and chromium Vincent du Vigneaud (1901–1978), 1955 Nobel Prize in Chemistry Artturi Ilmari Virtanen (1895–1973), chemist, Nobel Prize laureate Max Volmer, Germany (1885–1965) Alessandro Volta (1745–1827), Italian electrochemist, invented the voltaic cell Alexander Vinogradov (1895-1975), Soviet geochemist
Selenium, in the form of organoselenium compounds, is an essential micronutrient whose absence from the diet causes cardiac muscle and skeletal dysfunction. Organoselenium compounds are required for cellular defense against oxidative damage and for the correct functioning of the immune system. They may also play a role in prevention of premature aging and cancer. The source of Se used in biosynthesis is selenophosphate. Glutathione oxidase is an enzyme with a selenol at its active site. Organoselenium compounds have been found in higher plants. For example, upon analysis of garlic using the technique of high-performance liquid chromatography combined with inductively coupled plasma mass spectrometry (HPLC-ICP-MS), it was found that γ-glutamyl-Se-methylselenocysteine was the major Se-containing component, along with lesser amounts of Se-methylselenocysteine. Trace quantities of dimethyl selenide and allyl methyl selenide are found in human breath after consuming raw garlic. Indeed, organoselenium compounds have a terrible smell.
The enzyme cystathionine γ-lyase (EC 4.4.1.1, CTH or CSE; also cystathionase; systematic name L-cystathionine cysteine-lyase (deaminating; 2-oxobutanoate-forming)) is an enzyme which in humans is encoded by the gene CTH. CTH enzymes break down cystathionine into cysteine, 2-oxobutanoate (α-ketobutyrate), and ammonia:
Pu(III), as Pu3+ (blue lavender) Pu(IV), as Pu4+ (yellow brown) Pu(V), as PuO+2 (light pink) Pu(VI), as PuO2+2 (pink orange) Pu(VII), as PuO3−5 (green)—the heptavalent ion is rare. The color shown by plutonium solutions depends on both the oxidation state and the nature of the acid anion. It is the acid anion that influences the degree of complexing—how atoms connect to a central atom—of the plutonium species. Additionally, the formal +2 oxidation state of plutonium is known in the complex [K(2.2.2-cryptand)] [PuIICp″3], Cp″ = C5H3(SiMe3)2. Preparation of plutonium(VIII) compounds such as the volatile tetroxide PuO4 has also been claimed, but their existence remains disputed. Metallic plutonium is produced by reacting plutonium tetrafluoride with barium, calcium or lithium at 1200 °C. Metallic plutonium is attacked by acids, oxygen, and steam but not by alkalis and dissolves easily in concentrated hydrochloric, hydroiodic and perchloric acids. Molten metal must be kept in a vacuum or an inert atmosphere to avoid reaction with air. At 135 °C the metal will ignite in air and will explode if placed in carbon tetrachloride.
Sources: en.wikipedia.org
Dry powder is normally held at -20 °C or lower, away from light and moisture. Sealed vials can also be kept at 2-8 °C for shorter intervals. Warming to room temperature before opening prevents condensation.
In solution, hydrolysis of peptide bonds and oxidation of the methionine residue are the principal concerns. Oxidation converts methionine to its sulfoxide form, shifting the mass by sixteen daltons. Both processes are slowed by cold storage and by avoiding alkaline conditions.
A certificate documents what the supplier measured on a specific lot, not how a laboratory will use the material. Independent verification of identity and purity is common practice. Acceptance criteria should be defined before a batch is ordered.
It is a short synthetic peptide built from seven amino acids: methionine, glutamic acid, histidine, phenylalanine and three prolines. The sequence derives from the 4-10 fragment of adrenocorticotropic hormone with an added proline-glycine-proline tail. No plant or animal extract is involved; the material is produced by solid-phase peptide synthesis.