peptide degradation is one of those subjects where the details matter more than the headlines. This page pulls together the background, the mechanisms, and the practical points readers ask about most.
Last reviewed on 2026-07-04. Where a claim depends on a specific study, the study is described rather than over-claimed.
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.
The compound is registered in Russia as a pharmaceutical product, most commonly formulated as a nasal solution, and has been used in that setting since the 1990s. Outside that jurisdiction it is generally handled as a research chemical rather than an approved medicine. Regulatory status therefore differs sharply between countries, and material sold internationally may not correspond to the Russian pharmaceutical formulation. Documentation with commercial samples is typically limited to a certificate of analysis covering purity and identity, not clinical status or local legal classification.
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.
| 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 |
各国监管态度分化明显。俄罗斯按处方药管理，部分东欧国家留有使用记录；欧盟与美国未批准其作为药物上市，市面流通品通常标注为研究用化学品。身份差异意味着标示含量、纯度与无菌性缺少统一核查。体育领域还牵涉反兴奋剂名录，跨境携带则受目的地药品法规约束。
Semax 是人工设计的七肽，序列为 Met-Glu-His-Phe-Pro-Gly-Pro，骨架取自促肾上腺皮质激素片段 ACTH(4-10)。它于二十世纪八十年代在苏联的分子遗传学研究机构内合成。设计目标是保留该片段与注意力和记忆相关的活性，同时剔除促皮质激素释放等内分泌作用。此后俄罗斯将其登记为药品并进入临床使用。
当时的短肽研究普遍关注能否穿越血脑屏障、在低剂量下产生中枢效应，Semax 属于这一路线。鼻内给药是其主要使用方式，俄语文献报道的适应症涵盖缺血性卒中、短暂性脑缺血发作、认知功能减退以及视神经病变。这些研究大多发表在当地期刊上，样本规模与终点设置同西方试验惯例存在差异，国际同行对其临床证据的强度看法不一。
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。
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.
== Diagnosis == Urbach–Wiethe disease is typically diagnosed by its clinical dermatological manifestations, particularly the beaded papules on the eyelids. Doctors can also test the hyaline material with a periodic acid-Schiff (PAS) staining, as the material colors strongly for this stain. Immunohistochemical skin labeling for antibodies for the ECM1 protein as labeling has been shown to be reduced in the skin of those affected by Urbach–Wiethe disease. Staining with anti-type IV collagen antibodies or anti-type VII collagen antibodies reveals bright, thick bands at the dermoepidermal junction. Non-contrast CT scans can image calcifications, but this is not typically used as a means of diagnosing the disease. This is partly due to the fact that not all Urbach-Wiethe patients exhibit calcifications, but also because similar lesions can be formed from other diseases such as herpes simplex and encephalitis. The discovery of mutations within the ECM1 gene has allowed the use of genetic testing to confirm initial clinical diagnoses of Urbach–Wiethe disease. It also allows doctors to better distinguish between Urbach–Wiethe disease and other similar diseases not caused by mutations in ECM1.
Nicotinamide mononucleotide ("NMN" and "β-NMN") is a nucleotide derived from ribose, nicotinamide, nicotinamide riboside and niacin. In humans, several enzymes use NMN to generate nicotinamide adenine dinucleotide (NADH). In mice, it has been proposed that NMN is absorbed via the small intestine within 10 minutes of oral uptake and converted to nicotinamide adenine dinucleotide (NAD+ form) through the Slc12a8 transporter. However, this observation has been challenged, and the matter remains unsettled. Because NADH is a cofactor for processes inside mitochondria, for sirtuins and PARP, NMN has been studied in animal models as a potential neuroprotective and anti-aging agent. The alleged anti-aging effect at the cellular level by inhibiting mitochondrial decay in presence of increased levels of NAD+ makes it popular among anti-aging products. Dietary supplement companies have aggressively marketed NMN products, claiming those benefits. However, no human studies to date have properly proven its anti-aging effects with proposed health benefits only suggested through research done in vitro or through animal models. Single-dose administration of up to 500 mg was shown safe in men in a study at Keio University. One 2021 clinical trial found that NMN improved muscular insulin sensitivity in prediabetic women, while another found that it improved aerobic capacity in amateur runners. A 2023 clinical trial showed that NMN improves performance on a six-minute walking test and a subjective general health assessment.
==== Vitamin D2 ==== Plants Alfalfa (Medicago sativa subsp. sativa), shoot: 4.8 μg (192 IU) vitamin D2, 0.1 μg (4 IU) vitamin D3 Fungus, from USDA nutrient database, per 100 g: Mushrooms, portabella, exposed to ultraviolet light, raw: Vitamin D2: 11.2 μg (446 IU) Mushrooms, portabella, exposed to ultraviolet light, grilled: Vitamin D2: 13.1 μg (524 IU) Mushrooms, shiitake, dried: Vitamin D2: 3.9 μg (154 IU) Mushrooms, shiitake, raw: Vitamin D2: 0.4 μg (18 IU) Mushrooms, portabella, raw: Vitamin D2: 0.3 μg (10 IU) Mushroom powder, any species, illuminated with sunlight or artificial ultraviolet light sources Vitamin D2, or ergocalciferol is found in fungus (except alfalfa which is a plantae) and created from viosterol, which in turn is created when ultraviolet light activates ergosterol (which is found in fungi and named as a sterol from ergot). Any UV-irradiated fungus including yeast form vitamin D2. Human bioavailability of vitamin D2 from vitamin D2-enhanced button mushrooms via UV-B irradiation is effective in improving vitamin D status and not different from a vitamin D2 supplement according to study. For example, vitamin D2 from UV-irradiated yeast baked into bread is bioavailable. By visual assessment or using a chromometer, no significant discoloration of irradiated mushrooms, as measured by the degree of "whiteness", was observed making it hard to discover if they have been treated without labeling. Claims have been made that a normal serving (approx.
=== Other drugs === Certain medications can decrease the absorption of orally consumed vitamin B12, including colchicine, extended-release potassium products, and antibiotics such as gentamicin, neomycin and tobramycin. Anti-seizure medications phenobarbital, pregabalin, primidone and topiramate are associated with lower than normal serum vitamin concentration. However, serum levels were higher in people prescribed valproate. In addition, certain drugs may interfere with laboratory tests for the vitamin, such as amoxicillin, erythromycin, methotrexate and pyrimethamine.
Sources: en.wikipedia.org
Until the end of the 19th century, the history of Upper Volta was dominated by the empire-building Mossi/Mossi Kingdoms, who are believed to have come up to their present location from present-day northern Ghana. For centuries, the Mossi peasant was both farmer and soldier, and the Mossi people were able to defend their religious beliefs and social structure against forcible attempts to convert them to Islam by Muslims from the northwest. When the French arrived and claimed the area in 1896, Mossi resistance ended with the capture of their capital at Ouagadougou. In 1919, certain provinces from Upper Senegal and Niger were united into a separate colony called the Upper Volta in the French West Africa federation. In 1932, the new colony was dismembered in a move to economise; it was reconstituted in 1937 as an administrative division called the Upper Coast. After World War II, the Mossi renewed their pressure for separate territorial status and on 4 September 1947, Upper Volta became a French West African territory again in its own right. The indigenous population was highly discriminated against. For example, African children were not allowed to ride bicycles or pick fruit from trees, "privileges" reserved for the children of colonists. Violating these regulations could land parents in jail. A revision in the organisation of French overseas territories began with the passage of the Basic Law (Loi Cadre) of 23 July 1956.
== Major families == The barrier for a regular protein to become a selenoprotein is relatively high due to the requirement for a SECIS element. As a result, new selenoprotein families do not easily appear. It is also not uncommon for these families to include non-selenoprotein descendants, as (mainly terristial) selenium-poor environments provide a fitness advantage to an organism that has lower requirements of selenium. The below will focus on families found in humans.
Eastern countries such as China and Russia and most Muslim nations like Iran, Indonesia and Pakistan remained staunchly opposed." The outcome document recommended treatment, prevention and other public health measures, and committed to "intensifying our efforts to prevent and counter" drug production and trafficking, through, "inter alia, more effective drug-related crime prevention and law enforcement measures." A statement signed by 189 civil society organizations criticized the 2016 outcome document, itemizing the lack of progress and calling out the "highly problematic, non-inclusive and non-transparent" process that made it possible for "a handful of vocal and regressive countries [to] block progressive language", resulting in "an expensive restatement of previous agreements and conventions".
=== Radioactive isotopes === The existence of isotopes was first suggested in 1913 by the radiochemist Frederick Soddy, based on studies of radioactive decay chains that indicated about 40 different species referred to as radioelements (i.e. radioactive elements) between uranium and lead, although the periodic table only allowed for 11 elements between lead and uranium inclusive. Several attempts to separate these new radioelements chemically had failed. For example, Soddy had shown in 1910 that mesothorium (later shown to be 228Ra), radium (226Ra, the longest-lived isotope), and thorium X (224Ra) are impossible to separate. Attempts to place the radioelements in the periodic table led Soddy and Kazimierz Fajans independently to propose their radioactive displacement law in 1913, to the effect that alpha decay produced an element two places to the left in the periodic table, whereas beta decay emission produced an element one place to the right. Soddy recognized that emission of an alpha particle followed by two beta particles led to the formation of an element chemically identical to the initial element but with a mass four units lighter and with different radioactive properties. Soddy proposed that several types of atoms (differing in radioactive properties) could occupy the same place in the table. For example, the alpha-decay of uranium-235 forms thorium-231, whereas the beta decay of actinium-230 forms thorium-230.
Loratadine, sold under the brand name Claritin among others, is a medication used to treat allergies. This includes allergic rhinitis (hay fever) and hives. It is also available in drug combinations such as loratadine/pseudoephedrine, in which it is combined with pseudoephedrine, a nasal decongestant. It is taken orally. Common side effects include sleepiness, dry mouth, and headache. Serious side effects are rare and include allergic reactions, seizures, and liver problems. Use during pregnancy appears to be safe but has not been well studied. It is not recommended in children less than two years old. It is in the second-generation antihistamine family of medications. Loratadine was patented in 1980 and came to market in 1988. It is on the World Health Organization's List of Essential Medicines. Loratadine is available as a generic medication. In the United States, it is available over the counter. In 2023, it was the 105th most commonly prescribed medication in the United States, with more than 6 million prescriptions; and the combination with pseudoephedrine was the 300th most commonly prescribed medication in the United States, with more than 400,000 prescriptions.
Sources: en.wikipedia.org
25 June – A study indicates that the Arctic is warming four times faster than global warming now, substantially faster than current CMIP6 models could project. 27 June With a small catalog of unknown bacteria, researchers suggest work on microbes soon to be released from melting glaciers across the world to identify and understand potential threats in advance and understand extremophiles. Progress in climate change mitigation (CCM) living review-like works:The living document-like aggregation, assessment, integration and review website Project Drawdown adds 11 new CCM solutions to its organized set of mitigation techniques. The website's modeling framework is used in a study document to show that metal recycling has significant potential for CCM (2 June). A revised or updated version of a major worldwide 100% renewable energy proposed plan and model is published (28 June). 28 June Physicists report that interstellar quantum communication by other civilizations could be possible and may be advantageous, identifying some potential challenges and factors for detecting such. They may use, for example, X-ray photons for remotely established channels and quantum teleportation as the communication mode. A review elucidates the current state of climate change extreme event attribution science, concluding probabilities and costs-severities of links as well as identifying potential ways for its improvement. 30 June Samsung announces the first mass production of computer chips using a 3 nm process.
== Methodology == To begin HPTLC, a stationary phase has to be determined to separate different compounds within a mixture. Around 90% of all pharmaceutical separations are performed on normal phase silica gel; however, other stationary phases such as alumina can be used for samples with dissociating compounds and cellulose for ionic compounds. The reverse-phase HPTLC method (similar methodology to reverse-phase TLC) is used for compounds with high polarity. After the selection of the stationary phase, plates are generally washed with methanol and dried in an oven to remove excess solvent. Selection for the mobile phase is one of the most important processes of HPTLC and follows a 'trial and error' pathway. However, the 'PRISMA' system stands as a guideline for finding the optimal mobile phase. The mobile phase is dependent on the absorptivity of the stationary phase and the composition of the compound of interest. The compound is first tested with solutions such as diethyl ether, ethanol, dichloromethane, chloroform for normal phase HPTLC, or solutions such as methanol, acetonitrile, and tetrahydrofuran for reverse phase HPTLC. The retardation factors (Rf) of the compounds with the selected solvent are then analyzed and the solvent that gives the largest Rf is chosen to be the mobile phase for the compound. Then, the mobile solvent strength is tested against hexane (for normal HPTLC) and water (for reverse-phase HPTLC) to determine the need for adjustment.
In order to better assess radiation protection, the number of X-ray examinations, including the dose, has been recorded annually in Germany since 2007. However, the Federal Statistical Office does not have complete data for conventional X-ray examinations. In 2014, the total number of X-ray examinations in Germany was estimated to be about 135 million, of which about 55 million were dental X-ray examinations. The average effective dose from x-ray examinations per inhabitant in Germany in 2014 was about 1.55 mSv (about 1.7 x-ray examinations per inhabitant per year). The proportion of dental X-rays is 41%, but accounts for only 0.4% of the collective effective dose. In Germany, Section 28 of the X-ray Ordinance (RöV) has required since 2002 that the attending physician must have an X-ray pass available for X-ray examinations and offer it to the patient. The pass contains information about the patient's X-rays to avoid unnecessary examinations and to allow comparison with previous images. With the entry into force of the new Radiation Protection Ordinance on December 31, 2018, this obligation no longer applies. In Austria and Switzerland, x-ray passports have so far been available voluntarily. In principle, there must always be both a justifiable indication for the use of X-rays and the informed consent of the patient. In the context of medical treatment, informed consent refers to the patient's agreement to all types of interventions and other medical measures. § 630d Act of (in German)
[19], healthy trees outside of intensively managed environments are unlikely to sustain serious permanent damage from these insects. Both in silvicultural and natural contexts, the beetles themselves remain the most problematic and worrisome components of the symbiosis, and A. roeperi is not in and of itself a severe tree disease, merely a critical foundation for X. crassiusculus nutrition. Disrupting the relationship between fungus and beetle may thus someday provide fruitful avenues for pest control.
Theories suggest the claustrum may act to bind and integrate multisensory information, or else to encode sensory stimuli as salient or nonsalient (Mathur, 2014). One theory suggests the claustrum harmonizes and coordinates activity in various parts of the cortex, leading to the seamless integrated nature of subjective conscious experience (Crick and Koch, 2005; Stiefel et al., 2014). Disrupting claustral activity may lead to conscious experiences of disintegrated or unusually bound sensory information, perhaps including synesthesia. Such theories are in part corroborated by the fact that [salvia divinorum], which functions almost exclusively on the KOR system, can cause consciousness to be decoupled from external sensory input, leading to experiencing other environments and locations, perceiving other "beings" besides those actually in the room, and forgetting oneself and one's body in the experience. From this perspective, disrupting claustral activity might lead to conscious experiences of disintegrated or unusually bound sensory information, including synesthesia. However, even early formulations acknowledged that their assumptions are merely tentative and that "KORs are not exclusive to the claustrum; there is also a fairly high density of receptors located in the prefrontal cortex, hippocampus, nucleus accumbens and putamen", and that "disruptions to other brain regions could also explain the consciousness-altering effects [of salvinorin A]".
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.
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.