This is a working overview of Lyophilisation, written for readers who want more than a one-paragraph summary but less than a textbook.
This page was last updated on 2026-08-01 and is reviewed periodically as new material appears.
Semax is a synthetic heptapeptide with the sequence Met-Glu-His-Phe-Pro-Gly-Pro. Its chain combines the first seven residues of corticotropin with a C-terminal proline-glycine-proline extension, a modification intended to slow enzymatic breakdown. The free peptide has a molecular mass near 813.9 daltons. It belongs to the class of ACTH-derived fragments studied for central nervous system activity rather than for adrenal steroid stimulation. This structural relationship to a natural hormone fragment is the usual starting point for describing the compound in the literature.
Development took place during the 1980s at institutes of the Russian Academy of Sciences, where peptide fragments of ACTH were screened for cognitive and neuroprotective effects. The compound received regulatory approval in Russia as a nasal preparation, marketed for conditions such as ischemic stroke, transient ischemic attacks, and optic nerve disorders. Registration in other countries has not followed. Most published clinical reports originate from a small number of Russian research groups, and independent replication outside that setting remains limited. The regulatory status therefore differs sharply between Russia and the rest of the world.
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.
Solid material is normally kept at minus 20 degrees Celsius in a sealed, desiccated container. Reconstituted solutions are less stable and are usually divided into single-use aliquots before freezing. Repeated freeze-thaw cycles are avoided because they promote aggregation and loss of activity. Light exposure is minimized by using amber glassware or foil wrapping. Published stability data for this peptide are sparse, so recommended storage conditions rest mainly on general practice for short synthetic peptides rather than on dedicated study.
| Property | Value | Notes |
|---|---|---|
| Sequence | Met-Glu-His-Phe-Pro-Gly-Pro | Heptapeptide; ACTH(4-10) analog extended at C-terminus |
| Molecular mass | ~813.9 Da | Free peptide, unmodified |
| Appearance | White to off-white powder | Typical lyophilized solid |
| Solubility | Soluble in water and saline | Also soluble in common aqueous buffers |
| Storage (solid) | -20 °C, desiccated | Protect from moisture and repeated thawing |
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 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。
溶液状态的稳定性明显低于冻干粉。肽类在水溶液中可能经历水解、氧化与聚集，其中甲硫氨酸和天冬酰胺等残基常是敏感位点。Semax 含有甲硫氨酸，因此氧化风险相对突出。工作液一般主张现配现用，或冷藏并在数日内用尽。缓冲液种类、pH 和离子强度都会影响降解速率，而关于最佳条件的公开数据并不统一。
常规纯度与身份确认依赖反相高效液相色谱，并辅以质谱测定分子量。氨基酸组成分析可用于验证序列构成，肽图分析则能进一步定位修饰或降解产物。杂质谱通常关注缺失序列肽、截短片段和氧化产物。不同方法的检出限并不相同，因此各实验室报告的纯度数值不宜直接横向比较。
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.
Material sold for laboratory use varies widely in stated purity and documentation. A certificate of analysis should list the analytical method, the column and detector used, and the observed purity value. Independent verification by an outside laboratory is the practical way to confirm identity when documentation is absent or internally inconsistent. Regulatory status differs by country, and a product legal in one jurisdiction may be unapproved or controlled in another.
Identity and purity of semax are established with reversed-phase high-performance liquid chromatography coupled to ultraviolet detection, usually at 214 nanometres. Mass spectrometry, most often electrospray ionisation in positive mode, confirms the molecular mass and reveals truncated sequences. Amino acid analysis and peptide mapping after enzymatic digestion provide additional structural confirmation. Laboratories typically report purity as the percentage area of the main peak, a figure that does not capture isomeric or oxidised variants unless the method resolves them.
=== Artificial === As well as humans and other biological species, sentient artificial intelligences are also members of the Culture. These can be broadly categorised into drones and Minds. Also, by custom, as described in Excession, any artifact (be it a tool or vessel) above a certain capability level has to be given sentience.
== History == The disease was first described by German neurologist Hans Gerhard Creutzfeldt in 1920 and shortly afterward by Alfons Maria Jakob, giving it the name Creutzfeldt–Jakob disease. Some of the clinical findings described in their first papers do not match current criteria for Creutzfeldt–Jakob disease, and it has been speculated that at least two of the people in the initial studies had a different illness. An early description of familial CJD stems from the German psychiatrist and neurologist Friedrich Meggendorfer (1880–1953). A study published in 1997 counted more than 100 cases worldwide of transmissible CJD and new cases continued to appear at the time. The first report of suspected iatrogenic CJD was published in 1974. Animal experiments showed that corneas of infected animals could transmit CJD, and the causative agent spreads along visual pathways. A second case of CJD associated with a corneal transplant was reported without details. In 1977, CJD transmission caused by silver electrodes previously used in the brain of a person with CJD was first reported. Transmission occurred despite the decontamination of the electrodes with ethanol and formaldehyde. Retrospective studies identified four other cases likely of a similar cause. The rate of transmission from a single contaminated instrument is unknown, although it is not 100%. In some cases, the exposure occurred weeks after the instruments were used on a person with CJD.
== Contraindications == Oliceridine should not be given to people with significant respiratory depression; acute or severe bronchial asthma in an unmonitored setting or in the absence of resuscitative equipment; known or suspected gastrointestinal obstruction; or known hypersensitivity to the medication.
Examples of botanically classified fruit that are typically called vegetables include cucumber, pumpkin, and squash or other winter squashes (all are cucurbits); beans, peanuts, and peas (all legumes); and corn, eggplant, bell pepper (or sweet pepper), and tomato. Many spices are fruits, botanically speaking, including black pepper, chili pepper, cumin and allspice. In contrast, rhubarb is often called a fruit when used in making pies, but the edible produce of rhubarb is actually the leaf stalk or petiole of the plant. Botanically, a cereal grain, such as corn, rice, or wheat is a kind of fruit (termed a caryopsis). However, the fruit wall is thin and fused to the seed coat, so almost all the edible grain-fruit is actually a seed.
Sources: en.wikipedia.org
=== Chemical characteristics === Hydrogel dressings exhibit chemical or physical cross-linking. Chemical cross-linking involves formation of covalent bonds between polymer chains. Chemically cross-linked hydrogel dressings are synthesized by chain-growth polymerization, step-growth polymerization, enzymes, or irradiation polymerization. Synthetic dressings incorporating nanoparticles such as PVA and polyethylene glycol (PEG) are assembled using chemical cross-linking mechanisms. Physically cross-linked hydrogel dressings are assembled via ionic interaction, hydrogen bonding, hydrophobic interactions, or crystallization. Physically cross-linked hydrogels disintegrate due to local changes in pH, ionic strength, and temperature. Natural dressings incorporating polysaccharides and proteoglycans/proteins form a 3D network using physical cross-linking. Hydrogel dressings mimic the cross-linked 3D network of extracellular matrix fibers in human skin. Hydrogels can be formed through a self-assembly process in which monomers diffuse in solution then form noncovalent interactions. Hydrogels used in wound dressings can be self-assembled upon addition of divalent metal cations or electrically charged polysaccharides due to electrostatic interactions. Self-assembly via hydrophobic interactions can be induced in amphiphilic polysaccharide-based gels by addition of water; it can also be induced in non amphiphilic polysaccharide-based hydrogels by the addition of hydrophobic grafts.
Sea containers for sale provide an accessible and convenient solution, meeting diverse needs and promoting sustainability through their reuse. Reusable steel boxes for use as truck-sized shipping containers first came into use around 1956. It took some time for businesses to devise a structured process to utilize and to get optimal benefits from the role and use of shipping containers. Over time, the invention of the modern telecommunications of the late 20th-century made it highly beneficial to have standardized shipping containers, and made these shipping processes more standardized, modular, easier to schedule and easier to manage.
== Techniques == The tools and techniques of ornithology are varied, and new inventions and approaches are quickly incorporated. The techniques may be broadly dealt under the categories of those that are applicable to specimens and those that are used in the field, but the classification is rough and many analysis techniques are usable both in the laboratory and field or may require a combination of field and laboratory techniques.
==== MeSH D13.695.578 – polynucleotides ==== MeSH D13.695.578.424 – oligonucleotides MeSH D13.695.578.424.224 – aptamers, nucleotide MeSH D13.695.578.424.450 – oligodeoxyribonucleotides MeSH D13.695.578.424.450.275 – DNA primers MeSH D13.695.578.424.480 – oligonucleotides, antisense MeSH D13.695.578.424.480.640 – oligodeoxyribonucleotides, antisense MeSH D13.695.578.424.480.645 – oligoribonucleotides, antisense MeSH D13.695.578.424.500 – oligoribonucleotides MeSH D13.695.578.424.600 – pyrimidine dimers MeSH D13.695.578.500 – polydeoxyribonucleotides MeSH D13.695.578.500.050 – apurinic acid MeSH D13.695.578.500.300 – poly da-dt MeSH D13.695.578.500.600 – poly t MeSH D13.695.578.550 – polyribonucleotides MeSH D13.695.578.550.050 – apurinic acid MeSH D13.695.578.550.500 – poly a MeSH D13.695.578.550.500.510 – poly a-u MeSH D13.695.578.550.530 – poly adenosine diphosphate ribose MeSH D13.695.578.550.560 – poly c MeSH D13.695.578.550.560.600 – poly i-c MeSH D13.695.578.550.600 – poly g MeSH D13.695.578.550.650 – poly i MeSH D13.695.578.550.650.600 – poly i-c MeSH D13.695.578.550.750 – poly u MeSH D13.695.578.550.750.510 – poly a-u
Lord Norton, a former Oxford classmate of Charles’, tells Yasmin he always knew Charles to be a sexual predator going back to his Oxford days. Later, Yasmin hires Alondra—the woman from the yacht—who implies Charles abused girls as young as twelve and gently suggests Yasmin may have been a victim as well, causing Yasmin to break down. At the end of series 4, Yasmin, who has herself become a predatory figure by trafficking escorts to powerful men, repeatedly listens to Charles' final voicemail inviting her on the boat trip.
Sources: en.wikipedia.org
Some vented bottles, as well as bottles which use a collapsible liner collapses as the formula is drained, have been assessed favorably. They were reported to be comparable to a breastfeeding group in terms of milk intake, sucking patterns, and oxygenation. A 2012 study comparing two types of vented bottles with anti-vacuum features found no differences in infant growth between randomized groups. "Bottle A", a partial anti-vacuum design, was rated by parents as easier to assemble and clean. Infants fed using "Bottle A" were reported to engage in less "fussing", but no difference were found in "crying" or "colic" or in rates of ear infection. Health recommendations for the storage and handling of human milk typically focus on preventing the growth of dangerous bacteria, but some research is also being done on nutrition. Experimental studies have shown a degradation of retinol (Vitamin A) and α-Tocopherol (Vitamin E) content dependent upon the formation of bubbles in expressed breast milk and in formula. Seven models of bottles were studied, from six companies. Less degradation occurred when using a bottle feeding system designed to minimize the mixing of air with the bottle's contents.
== Total synthesis == Due to the high potency and clinical need for cancer treatments, epothilones have been the target of many total syntheses. The first group to publish the total synthesis of epothilones was S. J. Danishefsky et al. in 1996. This total synthesis of epothilone A was achieved via an intramolecular ester enolate-aldehyde condensation. Other syntheses of epothilones have been published by Nicolaou, Schinzer, Mulzer, and Carreira. In this approach, key building blocks aldehyde, glycidols, and ketoacid were constructed and coupled to the olefin metathesis precursor via an aldol reaction and then an esterification coupling. Grubbs' catalyst was employed to close the bis terminal olefin of the precursor compound. The resulting compounds were cis- and trans-macrocyclic isomers with distinct stereocenters. Epoxidation of cis- and trans-olefins yield epothilone A and its analogs. One of the total syntheses of epothilone B is outlined below and was described by the laboratory of K. C. Nicolaou. The retrosynthetic analysis revealed 1, 2, and 3 as the building blocks (Figure 1).
However, later on, within a more complex cellular environment, these highly hydrophobic LCRs became inappropriate or even toxic from a protein interaction perspective and have been selected against ever since. In addition, they further hypothesize that the very early protopeptides did not have a nucleic acid binding role, because DNA and RNA-binding LCRs are highly enriched in glycine, arginine and lysine, however, arginine and lysine are not among the amino acids of the proposed early genetic code.
If R1 is the inner cylinder radii and R2 is the outer cylinder radii, with constant applied pressure gradient between the two ends G = −dp/dx, the velocity distribution and the volume flux through the annular pipe are
Sources: en.wikipedia.org
Semax is a synthetic seven-amino-acid peptide derived from a fragment of corticotropin. It is used in Russia as a nasal preparation, while elsewhere it is studied as a research compound. It is not approved as a medicine in most countries.
Its sequence corresponds to the 4-10 region of corticotropin extended by three residues. This fragment lacks the region responsible for adrenal steroid release, so it is explored for neural rather than hormonal effects. The relationship explains the compound's classification among ACTH-derived peptides.
It holds approval in Russia for several neurological indications as a nasal spray or drop formulation. Regulatory agencies in the United States and the European Union have not approved it. Products sold elsewhere are generally labeled for research use only.
Solid peptide is best kept frozen at about minus 20 degrees Celsius in a sealed container with desiccant. It should be allowed to reach room temperature before opening to prevent condensation. Repeated warming and cooling of the same vial is discouraged.