intranasal route comes up often in conversation and rarely with the context attached. Here we lay out the basics in order, then work through the practical considerations.
Updated 2026-07-09. Numbers and descriptions here follow the published literature rather than marketing material.
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.
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.
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。
| Property | Value | Notes |
|---|---|---|
| Chemical class | Synthetic heptapeptide (ACTH fragment analog) | Not a steroid; does not belong to the melanocortin agonist drugs by marketing category |
| Molecular formula | C37H51N9O10S (commonly cited) | Reported values vary slightly with salt and counter-ion content |
| Appearance | White to off-white lyophilized powder | A single batch may appear as a loose cake or fluffy solid |
| Solubility | Freely soluble in water and aqueous buffer | Stock solutions are usually prepared in sterile water or saline |
| Typical storage | −20 °C or below, desiccated and protected from light | Seal opened vials promptly to limit moisture uptake |
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.
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.
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.
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。
=== Shape and Morphology === The shape of the apical foramen exhibits considerable variation across different teeth. While standard instrumentation assumes a circular geometry, the foramen can present as oval, uneven, semilunar, or even flat. Recent studies have identified the round configuration as the most prevalent overall, with reported frequencies ranging from 57% to 65.1% of sampled teeth. Specifically, Manva et al. classified 65.1% of foramina as round and 31% as oval, with rare occurrences of uneven (2.7%), semilunar (0.6%), and flat (0.6%). The distribution of these shapes varies by tooth type; for instance, the round shape was most frequently observed in mandibular canines (77.8%), whereas the flat shape was exclusively evident in maxillary second molars. Despite the dominance of round shapes in these recent studies, significant controversies exist in the literature. Some researchers have reported round configuration prevalence as high as 94%, while others have found oval shapes to be the most common in posterior teeth, with prevalence rates reaching 71% to 81%. Swathika et al. noted that oval shapes were present in 56.7% of maxillary central incisors but found them to be less common in posterior teeth (27%) than previously thought. These morphological variations, particularly oval and irregular shapes, pose clinical challenges during root canal therapy if standard round instruments are used.
Depolarization opens both the sodium and potassium channels in the membrane, allowing the ions to flow into and out of the axon, respectively. If the depolarization is small (say, increasing Vm from −70 mV to −60 mV), the outward potassium current overwhelms the inward sodium current and the membrane repolarizes back to its normal resting potential around −70 mV. However, if the depolarization is large enough, the inward sodium current increases more than the outward potassium current and a runaway condition (positive feedback) results: the more inward current there is, the more Vm increases, which in turn further increases the inward current. A sufficiently strong depolarization (increase in Vm) causes the voltage-sensitive sodium channels to open; the increasing permeability to sodium drives Vm closer to the sodium equilibrium voltage ENa≈ +55 mV. The increasing voltage in turn causes even more sodium channels to open, which pushes Vm still further towards ENa. This positive feedback continues until the sodium channels are fully open and Vm is close to ENa. The sharp rise in Vm and sodium permeability correspond to the rising phase of the action potential. The critical threshold voltage for this runaway condition is usually around −45 mV, but it depends on the recent activity of the axon. A cell that has just fired an action potential cannot fire another one immediately, since the Na+ channels have not recovered from the inactivated state. The period during which no new action potential can be fired is called the absolute refractory period.
In 2014, the Party General Office and State Council issued guidance on strengthening ideological education in colleges and universities. During Xi Jinping's tenure, numerous colleges and universities have established schools of Marxism. Xi has implemented a number of education reforms. Schools are required to adjust their opening hours to be consistent with work hours in their area so that parents can pick-up their children directly after work (in order to reduce reliance on private classes for adult supervision after school hours). Schools must also promote health by requiring outdoor physical education classes daily and providing eye examinations twice per term. Educational reforms have also limited the amount of homework students can be assigned. In 2021, Xi enacted the Double Reduction Policy (reducing excessive off-campus tutoring and reducing homework burdens), mandating schools may not assign homework to children to grades one and two, homework is limited to no more than 60 minutes for children in grades three to six, and no more than 90 minutes for middle school children. In July 2021, China enacted a series of rules designed to shutdown the private tutoring sector as part of its common prosperity program. Rules issued in July 2021 prohibits new registration of private tuition tutoring centers and required existing centers to re-organize as non-profits. Tuition centers are prohibited from being listed on the stock market or receiving "excessive capital." They are no longer permitted to offer tutoring on the weekends or during public holidays.
== NPU foundations == C-NPU has been managing the development of structured definitions for laboratory result information for the IFCC and IUPAC and making recommendations through papers, recommendations, and technical reports. These mostly joint documents are available from the old IUPAC website [Y].
GLP-1 possesses several physiological properties making it (and its functional analogs) a subject of intensive investigation as a potential treatment of diabetes mellitus, as these actions induce long-term improvements along with the immediate effects. Although reduced GLP-1 secretion has previously been associated with attenuated incretin effect in patients with type 2 diabetes, further research indicates that GLP-1 secretion in patients with type 2 diabetes does not differ from healthy subjects. The most noteworthy effect of GLP-1 is its ability to promote insulin secretion in a glucose-dependent manner. As GLP-1 binds to GLP-1 receptors expressed on pancreatic β cells, the receptors couple to G-protein subunits and activate adenylate cyclase, which increases the production of cAMP from ATP. Subsequently, activation of secondary pathways, including protein kinase A (PKA) and Epac2, alters cell ion channel activity, causing elevated levels of cytosolic Ca2+ that enhance exocytosis of insulin-containing granules. During the process, influx of glucose ensures sufficient ATP to sustain the stimulatory effect. Additionally, GLP-1 ensures the β cell insulin stores are replenished to prevent exhaustion during secretion by promoting insulin gene transcription, mRNA stability and biosynthesis. GLP-1 also increases β cell mass by promoting proliferation and neogenesis while inhibiting apoptosis. As both type 1 and 2 diabetes are associated with reduction of functional β cells, this effect is desirable in diabetes treatment.
Sources: en.wikipedia.org
Dalman et al. (2024) proposed the new name Tyrannosaurus mcraeensis for the holotype (NMMNH P-3698), referencing the McRae Group, the rock layers to which the Hall Lake Formation belongs. The holotype of T. mcraeensis is found in the strata that are around a few million years older than the accepted range of T. rex, which existed at the end of the Maastrichtian. The rock layers were initially estimated to date to between 72.7 and 70.9 Ma, correlating to the latest Campanian or earliest Maastrichtian. However, in a 2024 conference abstract, the specific stratigraphic layer which yielded T. mcraeensis was estimated to be younger than 69.0 ± 0.4 Ma and older than 66.0 Ma based on the sandstone from the same fossil locality, which would suggest that the age of T. mcraeensis is much closer to T. rex than previously thought. T. mcraeensis was estimated at 12 metres (39 ft) long, which is similar to the size of an adult T. rex. The two are distinguished by characters of the skull. Amongst these, the dentary of T. mcraeensis is proportionately longer and possesses a less prominent chin, and the lower jaw shallower than that of T. rex, suggesting a weaker bite. The teeth are likewise blunter and more laterally compressed, while the post orbital crests are less prominent. Likewise, the skeletal anatomy showcases shared characteristics with Tarbosaurus and Zhuchengtyrannus. The validity of T. mcraeensis was questioned by other researchers in 2025. Morrison and colleagues noted the uncertainty in the previous age estimate and argued that the inclusion of the titanosaurian fossil (cf.
=== Physical therapy === Physical therapy is generally recommended, however individualized protocols are required due to the variability of OI. Physical therapy is used to strengthen muscles, improve motility, improve flexibility, and help with weight maintenance, although it must be done in a gentle manner to minimize the risk of bone fracture. In people with OI, exercise often involves water aerobics, light resistance exercises, and walking, if the patient is able. However, even in patients with mild OI, contact sports, as well as activities likely to put unnecessary stress on the joints, such as jumping, are contraindicated due to the risks they pose. Individuals with more limited mobility are encouraged to change positions regularly throughout the day; people who sit in a wheelchair most or all of the day are recommended to get out of it every two hours, as a form of exercise, to decrease stiffness, and to prevent pressure ulcers. Individuals with moderate to severe OI, who require assistive mobility devices and adapted vehicles, face significant barriers to access wheelchair-accessible pools or gyms—they either may not have any in their area, nor the means to get there. Obesity may be more likely to present among those with severe OI, (especially after the age of 20,) and can, in some, cause further declines in mobility. Tilt table whole body vibration may also be done to increase the mobility of long-term immobilized (bedridden) patients with OI; in at least two cases, it helped bedridden children to be able to sit upright.
== Production == Reactor-grade plutonium from spent nuclear fuel contains various isotopes of plutonium. 238Pu makes up only one or two percent, but it may be responsible for much of the short-term decay heat because of its short half-life relative to other plutonium isotopes. Reactor-grade plutonium is not useful for producing 238Pu for RTGs because difficult isotopic separation would be needed. Pure plutonium-238 is prepared by neutron irradiation of neptunium-237, one of the minor actinides that can be recovered from spent nuclear fuel during reprocessing, or by the neutron irradiation of americium in a reactor. The targets are purified chemically, including dissolution in nitric acid to extract the plutonium-238. A 100 kg sample of light water reactor fuel that has been irradiated for three years contains only about 700 grams (0.7% by weight) of neptunium-237, which must be extracted and purified. In the US, the Department of Energy's Space and Defense Power Systems Initiative of the Office of Nuclear Energy processes 238Pu, maintains its storage, and develops, produces, transports and manages safety of radioisotope power and heating units for both space exploration and national security spacecraft. As of March 2015, a total of 35 kilograms (77 pounds) of 238Pu was available for civil space uses. Out of the inventory, 17 kg (37 lb) remained in a condition meeting NASA specifications for power delivery.
There are many types of freeze-dryers available, however, they usually contain a few essential components. These are a vacuum chamber, shelves, process condenser, shelf-fluid system, refrigeration system, vacuum system, and control system.
Sources: en.wikipedia.org
Potassium, in the form of potassium chloride is used as a medication to treat and prevent low blood potassium. Low blood potassium may occur due to vomiting, diarrhea, or certain medications. It is given by slow injection into a vein or by mouth.
=== Results === Cephalothin, a first generation cephalosporin for parenteral use was the first cephalosporin to become available for patients in the US in 1964. It was chosen for clinical trials from series of 7-ACA derivatives prepared at Eli Lilly. The second cephalosporin for parenteral use became available little later and was marketed in the US under the name Cephaloridine. The clinical successes of these two cephalosporins urged researchers to improve the pharmacological properties and develop more agents. Today we are left with thousands of semisynthesized analogues of natural cephalosporin compounds based on the knowledge gained by intensive research on the chemistry of those two starting materials.
Mineralocorticoid (aldosterone) deficiency or resistance can also cause hyperkalemia. Primary adrenal insufficiency are: Addison's disease and congenital adrenal hyperplasia (CAH) (including enzyme deficiencies such as 21α hydroxylase, 17α hydroxylase, 11β hydroxylase, or 3β dehydrogenase).
Sources: en.wikipedia.org
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.
It was developed in the Soviet Union during the early 1980s by groups at the Institute of Molecular Genetics in Moscow. Russian approval for intranasal use followed, and it has been marketed there since. Western laboratories encountered it mainly through translated literature and, later, through online research-chemical trade.
It holds a Russian registration as a prescription nasal product but has no approval from the European Medicines Agency or the United States Food and Drug Administration. Buyers outside Russia usually receive material sold strictly for laboratory research. That distinction matters because research-grade and pharmaceutical-grade products carry different documentation and testing expectations.
不存在。它是依据 ACTH 的一段序列人工设计的分子，天然蛋白质中找不到与之完全相同的七肽。名称属于研究代号，而非天然物质名。