Everything below concerns Methionine oxidation. We keep the language plain, cite what the science says, and separate well-supported claims from open questions.
Last reviewed on 2026-03-16. Where a claim depends on a specific study, the study is described rather than over-claimed.
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.
纯度评估以反相高效液相色谱为主，通过主峰面积百分比给出粗略结果，再配合电喷雾质谱核对分子量。氨基酸分析可验证组成比例，手性色谱或毛细管电泳用于检查残基构型。常见杂质包括缺失序列的短肽、氧化产物与二聚体。由于多数市售品不附带完整检验报告，独立第三方检测常被用来核实标称值。
从分子层面看，Semax 是线性七肽，没有二硫键、糖基或脂链修饰，N 端为游离氨基，C 端为游离羧基。分子含组氨酸与谷氨酸侧链，因此在水和甲醇等极性溶剂中溶解良好，在非极性溶剂中溶解有限。计算分子量约为 814 Da，与其质子化离子的质荷比吻合，可用于质谱确认。
| Property | Value | Notes |
|---|---|---|
| Primary research models | Rodent studies | Largest share of published data |
| Reported markers | BDNF and NGF expression | Measured mainly in animal tissue |
| Common administration | Intranasal | Matches the registered formulation |
| Blood residence time | Minutes | Rapid enzymatic degradation |
| Evidence quality | Small trials, limited replication | Noted repeatedly in reviews |
Practical handling follows from those properties. Bulk material is best divided into single-use portions soon after receipt, because each thaw exposes the whole container to moisture and temperature cycling. Vials should be allowed to reach room temperature before opening to prevent condensation on the powder. Low-binding plasticware reduces loss of dilute solutions, and sterile filtration is used when a preparation must remain free of microbial growth. Records of batch number, reconstitution date and storage history are what allow a later analytical result to be interpreted meaningfully.
Identity and purity of Semax are established mainly by reversed-phase high-performance liquid chromatography coupled with mass spectrometry. The chromatographic trace gives a purity estimate as a percentage of total peak area, while electrospray or matrix-assisted laser desorption ionization confirms the molecular mass against the calculated value. Amino acid analysis and sequence-specific fragmentation provide further confirmation when a supplier's chain of custody is unclear. Vendors frequently quote a purity figure without stating the detection wavelength or the integration method, which limits how far one number can be compared with another.
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.
Routine characterization relies on reversed-phase high-performance liquid chromatography to establish purity and on mass spectrometry to confirm molecular identity. Electrospray ionization and matrix-assisted laser desorption ionization are both used for mass verification. Amino acid analysis and peptide mapping can detect sequence errors. Common impurities include truncated sequences, methionine sulfoxide formed by oxidation, and deamidated products. Chromatograms are usually recorded near 214 nm, where the peptide backbone absorbs, and purity is reported as the percentage area of the principal peak.
Claims about enhanced focus, memory, or mood in healthy people rest mostly on anecdotal reports and community discussion rather than on controlled data. It remains unclear whether any cognitive benefit observed in patients recovering from brain injury would extend to uninjured users. Dose-response relationships, long-term safety, and interactions with other drugs are not well characterized in the peer-reviewed literature. Questions about optimal route of administration and treatment duration likewise remain open.
Semax binds to melanocortin receptors and is thought to influence neuronal survival and plasticity rather than to act through the adrenal axis. Laboratory work has shown increased expression of brain-derived neurotrophic factor and nerve growth factor in treated tissue. Changes in c-Fos, a marker of neuronal activation, have also been reported. Because the peptide is rapidly degraded by peptidases, its effects are generally attributed to downstream signaling cascades rather than to sustained receptor occupancy.
Published studies are dominated by animal models of stroke, ischemia, and cognitive impairment, with a smaller number of human trials conducted in Russia. Many of the human reports are small, single-center, and published in Russian-language journals, which limits independent scrutiny. Outcome measures vary between studies and often rely on clinician-rated scales rather than objective biomarkers. Systematic reviews have noted the methodological weaknesses and called for larger, preregistered trials before firm conclusions can be drawn.
== Finds == The body was identified as that of a person aged about 25 years, who had died in the first half of the 1st century BC. In addition to the sword in its bronze scabbard, a bronze mirror was found, and other grave goods included shield fittings, a sword belt ring, a brooch and a spiral ring (all of copper alloy), and a shattered tin object. All items were of classic celtic design. "There was also evidence for the grave having contained a sheepskin or fleece and woven textile incorporating goat and other animal hairs." The mirror and sword, after conservation, were given to the Isles of Scilly Museum, and as of 2023 are displayed in the museum's visitor centre in the town hall on St Mary's after the closure of the museum's building.
== S == Paul Sabatier (1854–1941), French chemist, 1912 Nobel Prize in Chemistry corecipient Frederick Sanger (1918–2013), 1958 and 1980 Nobel Prize in Chemistry Carl Wilhelm Scheele (1742–1786), Swedish 18th century chemist, discovered numerous elements Christian Friedrich Schönbein (1799–1868), German-Swiss chemist, invented the fuel cell, and discovered gun cotton and ozone Stuart L. Schreiber (born 1956), American chemist, a pioneer in a field of chemical biology Richard R. Schrock (born 1945), 2005 Nobel Prize in Chemistry Peter Schultz (born 1956), American chemist Glenn T. Seaborg (1912–1999), 1951 Nobel Prize in Chemistry Nils Gabriel Sefström (1787–1845), chemist Francesco Selmi (1817–1881), Italian chemist, regarded as one of the founders of colloid chemistry Nikolay Nikolayevich Semyonov (1896–1986), physicist and chemist, 1956 Nobel Prize in Chemistry T. R. Seshadri (1900–1975), Indian chemist, pioneer in plant chemistry K. Barry Sharpless (born 1941), 2001 Wolf Prize in Chemistry, 2001 Nobel Prize in Chemistry Dan Shechtman (born 1941), 2011 Nobel Prize in Chemistry, discovered quasicrystals Patsy O.
The epithelium is the innermost layer. It is where most digestive, absorptive and secretory processes occur. The lamina propria, the underlying layer of loose connective tissue within the mucosa. The muscularis mucosae, a thin layer of smooth muscle. The epithelium, the most exposed part of the mucosa, is a glandular epithelium with many goblet cells. Goblet cells secrete mucus, which lubricates the passage of food along and protects the intestinal wall from digestive enzymes. In the small intestine, villi are folds of the mucosa that increase the surface area of the intestine. The villi contain a lacteal, a vessel connected to the lymph system that aids in the removal of lipids and tissue fluids. Microvilli are present on the epithelium of a villus and further increase the surface area over which absorption can take place. Numerous intestinal glands as pocket-like invaginations are present in the underlying tissue. In the large intestines, villi are absent and a flat surface with thousands of glands is observed. Underlying the epithelium is the lamina propria, which contains myofibroblasts, blood vessels, nerves, and several different immune cells, and the muscularis mucosa which is a layer of smooth muscle that aids in the action of continued peristalsis and catastalsis along the gut.
Several studies have quantified the amounts of hallucinogenic compounds found in the fruit bodies of Psilocybe semilanceata. In 1993, Gartz reported an average of 1% psilocybin (expressed as a percentage of the dry weight of the fruit bodies), ranging from a minimum of 0.2% to a maximum of 2.37% making it one of the most potent species (but significantly less potent than panaeolus cyanescens). In an earlier analysis, Tjakko Stijve and Thom Kuyper (1985) found a high concentration in a single specimen (1.7%) in addition to a relatively high concentration of baeocystin (0.36%). Smaller specimens tend to have the highest percent concentrations of psilocybin, but the absolute amount is highest in larger mushrooms. A Finnish study assayed psilocybin concentrations in old herbarium specimens, and concluded that although psilocybin concentration decreased linearly over time, it was relatively stable. They were able to detect the chemical in specimens that were 115 years old. Michael Beug and Jeremy Bigwood, analyzing specimens from the Pacific Northwest region of the United States, reported psilocybin concentrations ranging from 0.62% to 1.28%, averaging 1.0 ±0.2%. They concluded that the species was one of the most potent, as well as the most constant in psilocybin levels. In a 1996 publication, Paul Stamets defined a "potency rating scale" based on the total content of psychoactive compounds (including psilocybin, psilocin, and baeocystin) in 12 species of Psilocybe mushrooms.
The effects of glaciation were global. Antarctica was ice-bound throughout the Pleistocene and the preceding Pliocene. The Andes were covered in the south by the Patagonian ice cap. There were glaciers in New Zealand and Tasmania. The decaying glaciers of Mount Kenya, Mount Kilimanjaro, and the Ruwenzori Range in east and central Africa were larger. Glaciers existed in the mountains of Ethiopia and to the west in the Atlas Mountains. In the northern hemisphere, many glaciers fused into one. The Cordilleran Ice Sheet covered the North American northwest; the Laurentide covered the east. The Fenno-Scandian ice sheet covered northern Europe, including Great Britain; the Alpine ice sheet covered the Alps. Scattered domes stretched across Siberia and the Arctic shelf. The northern seas were frozen. During the late Upper Paleolithic (Latest Pleistocene) c. 18,000 BP, the Beringia land bridge between Asia and North America was blocked by ice, which may have prevented early Paleo-Indians such as the Clovis culture from directly crossing Beringia to reach the Americas. According to Mark Lynas (through collected data), the Pleistocene's overall climate could be characterized as a continuous El Niño with trade winds in the south Pacific weakening or heading east, warm air rising near Peru, warm water spreading from the west Pacific and the Indian Ocean to the east Pacific, and other El Niño markers. The Paleolithic is often held to finish at the end of the ice age (the end of the Pleistocene epoch), and Earth's climate became warmer.
Sources: en.wikipedia.org
=== Iraqi === A United Nations report in March 1991 described the effect on Iraq of the US-led bombing campaign as "near apocalyptic", bringing back Iraq to the "pre-industrial age". The exact number of Iraqi combat casualties is unknown, but is believed to have been heavy. Some estimate that Iraq sustained between 20,000 and 35,000 fatalities. A report commissioned by the US Air Force estimated 10,000–12,000 Iraqi combat deaths in the air campaign, and as many as 10,000 casualties in the ground war. According to the Project on Defense Alternatives study, between 20,000 and 26,000 Iraqi military personnel were killed in the conflict, while 75,000 others were wounded. According to Kanan Makiya, "For the Iraqi people, the cost of enforcing the will of the United Nations has been grotesque." General Schwarzkopf talked about "a very, very large number of dead in these units, a very, very large number indeed." The chairman of the House Armed Services Committee, Les Aspin, estimated that "at least 65,000 Iraqi soldiers were killed". A figure was supported by Israeli sources who speak of "one to two hundred thousand Iraqi casualties." Most of the killing "took place during the ground war. Fleeing soldiers were bombed with a device known as a 'fuel-air explosive.'"
=== Female pheromones === cis-7-dodecenyl acetate cis-5-dodecenyl acetate 11-dodecenyl acetate cis-7-tetradecenyl acetate cis-9-tetradecenyl acetate dodecyl acetate Cabbage loopers are unique in that both females and males release pheromones in order to seek a mate. Generally, females release pheromones from the tips of their abdomens, and males seek females upon detection. Females around host plants are more attractive to males, possibly because females release more pheromones in the presence of host plant odor. Although it is not clear why host plant odors incite female pheromone production, this response may help reduce time wasted spent searching for a mate and therefore increase the chance of mating. Female cabbage loopers usually attract the male, as females have more to lose by spending energy and time on searching for a mate.
Routine toxicology studies have provided no evidence that moxonidine has any teratogenic, mutagenic or carcinogenic potential. No evidence has been found of serious adverse effects on organs or organ systems, and the drug has not been shown to have deleterious effects on perinatal or postnatal growth and development.
In Japan, public universities are run by local governments, either prefectural or municipal. According to the Ministry of Education, public universities have "provided an opportunity for higher education in a region and served the central role of intellectual and cultural base for the local community in the region" and are "expected to contribute to social, economical and cultural development in the region". This contrasts with the research-oriented aspects of national universities. In 2010, 127,872 students were attending 95 public universities, compared to 86 national universities and 597 private universities in Japan. Many public universities are relatively new; in 1980, there were only 34 public universities in Japan. Since July 2003, public universities may incorporate under the Local Independent Administrative Institutions Law.
In humans, melanin is the primary determinant of skin color. It is also found in hair, the pigmented tissue underlying the iris of the eye, and the stria vascularis of the inner ear. In the brain, tissues with melanin include the medulla and pigment-bearing neurons within areas of the brainstem, such as the locus coeruleus. It also occurs in the zona reticularis of the adrenal gland. The melanin in the skin is produced by melanocytes, which are found in the basal layer of the epidermis. Although, in general, human beings possess a similar concentration of melanocytes in their skin, the melanocytes in some individuals and ethnic groups produce variable amounts of melanin. The ratio of eumelanin (74%) and pheomelanin (26%) in the epidermis is constant regardless of the degree of pigmentation. Some humans have very little or no melanin synthesis in their bodies, a condition known as albinism. Because melanin is an aggregate of smaller component molecules, there are many different types of melanin with different proportions and bonding patterns of these component molecules. Both pheomelanin and eumelanin are found in human skin and hair, but eumelanin is the most abundant melanin in humans, as well as the form most likely to be deficient in albinism.
Sources: en.wikipedia.org
=== Down syndrome === Adults with Down syndrome had accumulation of amyloid in association with evidence of Alzheimer's disease, including declines in cognitive functioning, memory, fine motor movements, executive functioning, and visuospatial skills.
The body of a fish is divided into a head, trunk and tail, although the divisions between the three are not always externally visible. The skeleton, which forms the support structure inside the fish, is either made of cartilage, in cartilaginous fish, or bone in bony fish. The main skeletal element is the vertebral column, composed of articulating vertebrae which are lightweight yet strong. The ribs attach to the spine and there are no limbs or limb girdles. The main external features of the fish, the fins, are composed of either bony or soft spines called rays, which with the exception of the caudal fins, have no direct connection with the spine. They are supported by the muscles which compose the main part of the trunk. The heart has two chambers and pumps the blood through the respiratory surfaces of the gills and on round the body in a single circulatory loop. The eyes are adapted for seeing underwater and have only local vision. There is an inner ear but no external or middle ear. Low frequency vibrations are detected by the lateral line system of sense organs that run along the length of the sides of fish, and these respond to nearby movements and to changes in water pressure. Sharks and rays are basal fish with numerous primitive anatomical features similar to those of ancient fish, including skeletons composed of cartilage. Their bodies tend to be dorso-ventrally flattened, they usually have five pairs of gill slits and a large mouth set on the underside of the head. The dermis is covered with separate dermal placoid scales.
=== As a supplement === A series of studies showed that a combination of betaine and glycocyamine improves the symptoms of patients with chronic illness, including heart disease, without toxicity. Betaine can provide a methyl group to glycocyamine, via methionine, for the formation of creatine. In overall, such treatment led to less fatigue, greater strength and endurance, and an improved sense of well-being. The patients with cardiac decompensation (arteriosclerosis or rheumatic disease) and congestive heart failure had improved cardiac function. The patients gained weight (improved nitrogen balance) and saw lessened symptoms of arthritis and asthma and increased libido, and those people suffering from hypertension experienced transient reduced blood pressure. Also the studies shows the increase of glucose tolerance in both diabetic subjects and subjects without diabetes.
Under the 1992 constitution, the president was elected by the Federal Assembly of Yugoslavia for a four-year term. After the constitutional amendments of 2000, direct elections for the office of President were introduced. Under the 2003 constitution, the president was once again elected by the Assembly of Serbia and Montenegro for a four-year term, this time at the proposal of the president and vice president of the assembly. The president of Serbia and Montenegro was a member of the Supreme Defence Council together with the president of Serbia and the president of Montenegro, and served automatically as chairman of the council of ministers. Previously, the president and the prime minister had to be from different republics; now, with the posts merged, the president of the assembly had to be from a different republic from the president of Serbia and Montenegro, who in turn could not come from the same republic for more than two consecutive terms of office. The results of the direct presidential elections of 2000 were as follows:
== Adverse effects == Gastrointestinal adverse effects such as nausea and abdominal pain are extremely uncommon, and their frequency is substantially lower than with ibuprofen use. Increase in risk-taking behavior is possible. According to the U.S. Food and Drug Administration (FDA), the drug may cause rare and possibly fatal skin reactions such as Stevens–Johnson syndrome and toxic epidermal necrolysis, Rechallenge tests and an analysis of American but not French pharmacovigilance databases indicated a risk of these reactions. In clinical trials for osteoarthritis, the number of participants reporting adverse effects was similar for those on paracetamol and on placebo. However, the abnormal liver function tests (meaning there was some inflammation or damage to the liver) were almost four times more likely in those on paracetamol, although the clinical importance of this effect is uncertain. After 13 weeks of paracetamol therapy for knee pain, a drop in hemoglobin level indicating gastrointestinal bleeding was observed in 20% of participants, this rate being similar to the ibuprofen group. Due to the absence of controlled studies, most of the information about the long-term safety of paracetamol comes from observational studies. These indicate a consistent pattern of increased mortality as well as cardiovascular (stroke, myocardial infarction), gastrointestinal (ulcers, bleeding) and renal adverse effects with increased dose of paracetamol. Use of paracetamol is associated with 1.9 times higher risk of peptic ulcer.
Sources: en.wikipedia.org
The main proposal is modulation of neurotrophic factors such as brain-derived neurotrophic factor, supported largely by animal experiments. Receptor-level targets have not been firmly established. Most reviews describe the mechanism as only partially characterized.
The compound is registered as a medicine in Russia, so clinical work has concentrated there. Trials elsewhere are few and generally small. This geographic concentration is a recognized limitation in evidence reviews.
Some fraction may reach the central nervous system through olfactory pathways, and this is often cited as the rationale for the nasal route. The size of that fraction in humans is not well quantified. Blood concentrations after nasal dosing are low, which complicates measurement.
电喷雾或基质辅助激光解吸电离质谱是常用手段，测得的质子化离子质荷比可换算为分子量。结果与理论值落在合理误差内，才支持结构一致的判断。