Everything below concerns heptapeptide. We keep the language plain, cite what the science says, and separate well-supported claims from open questions.
Last reviewed on 2026-08-01. Where a claim depends on a specific study, the study is described rather than over-claimed.
Semax 是一种人工合成的七肽，氨基酸序列为 Met-Glu-His-Phe-Pro-Gly-Pro，单字母缩写记作 MEHFPGP。它被归类为促肾上腺皮质激素片段 ACTH(4-10) 的结构类似物，但并不天然存在于生物体内。母体片段 ACTH(4-10) 的序列为 Met-Glu-His-Phe-Arg-Trp-Gly，Semax 替换了中间两个残基，并在羧基端延长了 Pro-Gly-Pro 三肽。这种延长被普遍认为能提升分子对肽酶的耐受性。
该化合物于二十世纪八十年代在俄罗斯被开发，相关工作由俄罗斯科学院分子遗传学研究所的研究团队主导。开发目标并非复制 ACTH 的完整激素活性，而是寻找保留其神经作用方向、同时去除促肾上腺皮质激素释放效应的短肽片段。研究记录显示，这一方向促成了多个相关短肽的合成与筛选，而 Semax 是其中被研究最广泛的一个。当地文献常以 Семакс 这一名称指代它。
研究兴趣主要集中在神经营养因子相关的路径上，包括脑源性神经营养因子与神经生长因子的表达变化。部分实验报告称在特定条件下观察到这些因子的水平上升，但具体信号通路和剂量依赖关系仍未完全厘清。多数公开数据来自细胞模型和动物实验，人体对照研究数量有限。因此，该化合物的作用机制在文献中属于活跃讨论，而非已经确立的定论。
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.
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 |
|---|---|---|
| 化学类别 | 合成七肽 | ACTH(4-10) 结构类似物 |
| 氨基酸序列 | Met-Glu-His-Phe-Pro-Gly-Pro | 单字母写作 MEHFPGP |
| 分子量 | 约 813.9 Da | 随确切形式和盐型略有变化 |
| 常见同义词 | ACTH(4-10) 类似物 | 俄语文献称 Семакс |
| 开发来源 | 俄罗斯 | 二十世纪八十年代 |
NASA's aim for food on the ISS is to make the experience as close as possible to that of Earth, and they aim to provide more acceptable and palatable foods. Modern astronauts have a greater variety of main courses to choose from and many astronauts request personalized menus from lists of available foods including items like fruit salad and spaghetti. Fresh fruits and vegetables that can be safely stored at room temperature are eaten on space flights. Astronauts sometimes request beef jerky for flights, as it has an extended shelf life and a strong flavor. Food on the ISS is similar to the Shuttle, in that it is individually packaged to allow for exchanges and prevent issues in the microgravity environment. Due to the limited water supply, an emphasis has been placed on thermostabilized foods rather than rehydration methods. Since 2002, the small LADA Greenhouse system (the leaf chamber is just 16 x 20 x 26 cm/6 x 8 x 10 inches) has been used on board the International Space Station to study how plants grow in microgravity and to grow edible vegetables for the astronauts. LADA includes a control module and was sent to the station already equipped with the root media for the plants to be grown and eaten in space.
Thiamazole, also known as methimazole, is a medication used to treat hyperthyroidism. This includes Graves' disease, toxic multinodular goiter, and thyrotoxic crisis. It is taken by mouth. Full effects may take a few weeks to occur. Common side effects include itchiness, hair loss, nausea, muscle pain, swelling, and abdominal pain. Severe side effects may include low blood cell counts, liver failure, and vasculitis. Use is not recommended during the first trimester of pregnancy due to the risk of congenital anomalies, but it may be used in the second trimester or third trimester. It may be used during breastfeeding. Those who developed significant side effects may also have problems with propylthiouracil. Thiamazole is a cyclic thiourea derivative that works by decreasing the production of thyroid hormones. Thiamazole was approved for medical use in the United States in 1950. It is on the World Health Organization's List of Essential Medicines. It is available as a generic medication. It is also available in Europe and Asia. In 2023, it was the 255th most commonly prescribed medication in the United States, with more than 1 million prescriptions.
ISO 2171: Cereals, pulses and by-products — Determination of ash yield by incineration; ISO 3593: Starch — Determination of ash; ISO 928: Spices and condiments - Determination of total ash; and ISO 936: Meat and meat products - Determination of total ash. Examples of ash content methods for the determination of ash in other solids include
Sources: en.wikipedia.org
James Hibberd who commented for The Hollywood Reporter said that the trailer showed Homelander becoming more unstable after an apparent breakdown and also commenting over how the trailer also introduced a new formula that can turn anybody into a superhero for 24 hours, for which he complemented that Butcher might finally get the opportunity to be on the level of his nemesis and face him. Digital Spy's Shaun Wren deemed the trailer to be "packed with new heroes, gruesome scenes and a proper introduction to Jensen Ackles' original superhero Soldier Boy", and was excited to see the new developments that have taken during the time jump from the second to third season.
=== Discussed health risks === Like other foods, the consumption of edible insects could present health risks stemming from biological, toxicological, and allergenic hazards. Biological hazards include bacteria, viruses, protozoa, fungi and mycotoxins; toxological risks are poisons, pesticides, heavy metals and antinutrients; allergenic hazards relate to arginine kinase, tropomyosin and α-Amylase. Additionally, recent studies have indicated that proteins from yellow mealworm (Tenebrio molitor) may act as allergens, potentially triggering immunoglobulin E (IgE)-mediated allergic reactions and cross-reactivity, especially in individuals already sensitized to crustaceans or other arthropods. Chitin, a component of insect exoskeletons and other body parts, induces cytokine production in the digestive systems of humans and other mammals. Enzymes break the chitin down into smaller fragments, which trigger an immune response that results in inflammatory and allergic reactions. The human immune response to chitin is thought to be related to the abundance of dust mites as a cause of airway inflammatory disease and parasites as a cause of numerous diseases. In general, insects harvested from the wild pose a greater risk than farmed insects, and insects consumed raw pose a greater risk than insects that are cooked before consumption. Feed substrate and growing conditions are the main factors influencing the microbiological and chemical hazards of farmed insects.
== Diagnosis == Charcot–Marie–Tooth (CMT) disease can be diagnosed using a combination of three primary methods: nerve conduction studies, nerve biopsy, and genetic testing. Nerve conduction studies assess the velocity of electrical impulses traveling through nerves, whereas nerve biopsy entails the examination of small samples of nerve tissue. Genetic testing can conclusively diagnose CMT by identifying specific known mutations linked to the condition, though not all genetic markers for CMT are currently known. Initial signs of CMT often include lower-leg weakness, such as foot drop, and foot deformities like high arches or hammertoes. However, these symptoms alone do not provide enough information for a diagnosis. Individuals showing signs of CMT should be referred to a neurologist or rehabilitation medicine specialist for further evaluation and treatment. During a physical examination, the physician may assess muscle strength such as asking the patient to walk on their heels or resist applied pressure on their legs and check for sensory loss and reduced deep-tendon reflexes, such as the knee-jerk response. A detailed family history is also important, as CMT is an inherited condition. While the absence of a family history does not rule out CMT, it can help the physician distinguish it from other causes of neuropathy, such as diabetes, toxin exposure, or certain medications.
Sources: en.wikipedia.org
=== RNA molecules require a specific, complex three-dimensional structure for activity === The detailed three-dimensional structure of tRNA molecules was determined using X-ray crystallography, and revealed highly complex, compact three dimensional structures consisting of tertiary interactions laid upon the basic cloverleaf secondary structure. Key features of tRNA tertiary structure include the coaxial stacking of adjacent helices and non-Watson-Crick interactions among nucleotides within the apical loops. Additional crystallographic studies showed that a wide range of RNA molecules (including ribozymes, riboswitches and ribosomal RNA) also fold into specific structures containing a variety of 3D structural motifs. The ability of RNA molecules to adopt specific tertiary structures is essential for their biological activity, and results from the single-stranded nature of RNA. In many ways, RNA folding is more highly analogous to the folding of proteins rather than to the highly repetitive folded structure of the DNA double helix.
As the continental plates moved closer together, fragments of oceanic crust, islands, and other continental masses collided with the eastern margin of ancestral North America. By this time, plants had appeared on land, followed by scorpions, insects, and amphibians. The ocean continued to shrink until, about 270 million years ago, the continents that were ancestral to North America and Africa collided during the formation of the supercontinent Pangea. Because North America and Africa were once geographically connected, the Appalachians formed part of the same mountain chain as the Little Atlas in Morocco. This mountain range, known as the Central Pangean Mountains, extended into Scotland, before the Mesozoic Era opening of the Iapetus Ocean, from the North America/Europe collision (See Caledonian orogeny). By the end of the Mesozoic Era, the Appalachian Mountains had been eroded to an almost flat plain. It was not until the region was uplifted during the Cenozoic Era that the distinctive topography of the present formed. Uplift rejuvenated the streams, which rapidly responded by cutting downward into the ancient bedrock. Some streams flowed along weak layers that define the folds and faults created many millions of years earlier. Other streams downcut so rapidly that they cut right across the resistant folded rocks of the mountain core, carving canyons across rock layers and geologic structures.
After the tantalizing detection of phosphine (PH3) in the atmosphere of Venus, in the absence of known and plausible chemical mechanism to explain the formation of this molecule, the presence of micro-organisms in suspension in Venus's atmosphere has been suspected and the hypothesis of the microbial formation of phosphine has been formulated by Greaves et al. (2020) from Cardiff University envisaging the possibility of a liveable window in the Venusian clouds at a certain altitude with an acceptable temperature range for microbial life. Hallsworth et al. (2021) from the School of Biological Sciences at Queen's University Belfast have studied the conditions required to support the life of extremophile micro-organisms in the clouds at high altitude in the Venus atmosphere where favorable temperature conditions might prevail. Beside the presence of sulfuric acid in the clouds which already represent a major challenge for the survival of most micro-organisms, they came to the conclusion that the atmosphere of Venus is much too dry to host microbial life. Indeed, Hallsworth et al. (2021) have determined a water activity of ≤ 0.004, two orders of magnitude below the 0.585 limit for known extremophiles. So, with a water activity in the Venus clouds 100 times lower than the threshold of 0.6 known in Earth conditions, the hypothesis envisaged by Greaves et al. (2020) to explain the biotic origin of phosphine in the Venus atmosphere is ruled out.
==== Isotopes related to nuclear weapons ==== The aforementioned processes can be measured using naturally occurring isotopes. Nevertheless, anthropogenic isotopes are also extremely useful for oceanographic measurements. Nuclear weapons tests released a plethora of uncommon isotopes into the world's oceans. 3H, 129I, and 137Cs can be found dissolved in seawater, while 241Am and 238Pu are attached to particles. The isotopes dissolved in water are particularly useful in studying global circulation. For example, differences in lateral isotopic ratios within an ocean can indicate strong water fronts or gyres. Conversely, the isotopes attached to particles can be used to study mass transport within water columns. For instance, high levels of Am or Pu can indicate downwelling when observed at great depths, or upwelling when observed at the surface.
Sources: en.wikipedia.org
不是。Semax 是完全人工合成的七肽，自然界中没有对应的已知肽段。它的设计灵感来自促肾上腺皮质激素片段 ACTH(4-10)，但序列经过了替换和延长。
Semax 被描述为 ACTH(4-10) 的结构类似物，两者共享部分序列特征。它保留了该片段的部分神经相关活性方向，但去除了完整片段带来的激素释放效应。二者并非同一物质，也不能互相替代。
加入的 Pro-Gly-Pro 三肽被普遍认为能提升分子对蛋白水解酶的稳定性。这种设计让短肽在体内维持时间更长。具体延长的程度以及不同组织中是否一致，文献中仍存在不同报告。
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.