This is a working overview of nootropic, written for readers who want more than a one-paragraph summary but less than a textbook.
This page was last updated on 2025-11-11 and is reviewed periodically as new material appears.
Identity and purity are commonly assessed by reversed-phase high-performance liquid chromatography, with ultraviolet detection near 214 nanometers for the peptide backbone. Mass spectrometry, either electrospray or matrix-assisted laser desorption, confirms molecular mass and detects truncation or modification products. Amino acid analysis can verify composition. Because the sequence contains no strongly absorbing aromatic residue apart from phenylalanine, detection wavelengths are chosen carefully. Purity values above 95 percent are typical for research-grade material.
Quality documentation for research-grade peptide usually includes a certificate of analysis stating purity, identity, and residual counterion content. Batch-to-batch variation in purity and salt form is a recognized issue, and comparisons across suppliers require attention to the exact counterion, for example acetate versus trifluoroacetate. Sequence verification by tandem mass spectrometry provides stronger evidence than a single mass measurement. For any study reporting biological results, the analytical method and the measured purity should be stated explicitly. Independent verification of supplier claims is considered good practice.
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.
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。
| Property | Value | Notes |
|---|---|---|
| Typical purity | ≥95% by HPLC | Research-grade material |
| Detection wavelength | 214 nm | Peptide bond absorbance |
| Reconstitution medium | Sterile water or saline | Prepare fresh or aliquot immediately |
| Storage (solution) | -80 °C, single-use aliquots | Avoid repeated freeze-thaw cycles |
| Common salt form | Acetate or trifluoroacetate | Affects mass and solubility |
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.
The parent fragment ACTH(4-10) carries the sequence Met-Glu-His-Phe-Arg-Trp-Gly. Semax replaces the arginine and tryptophan positions with a proline-glycine-proline tail, giving Met-Glu-His-Phe-Pro-Gly-Pro. That change removes residues associated with adrenal stimulation, so the peptide does not drive cortisol release the way full ACTH does. This distinction shapes how the compound is grouped in the literature, where it sits with neuropeptides and peptide neuromodulators rather than with corticosteroids.
Regulatory status varies sharply by country. Semax is registered for medical use in Russia, where it appears in formularies as a nasal solution, and it also holds registration in a small number of neighbouring states. It has no approval from the United States Food and Drug Administration or the European Medicines Agency, and it is not a scheduled controlled substance in most jurisdictions. Elsewhere it circulates mainly as laboratory material, so purity documentation comes from suppliers rather than from a national pharmacopoeia.
Semax is a synthetic peptide created in the Soviet Union during the early 1980s by researchers working in Moscow. It was built from the short adrenocorticotropic hormone fragment known as ACTH(4-10), and the chain was then extended with three additional amino acids. The resulting molecule was named semax and entered clinical use in Russia in 1994. It is generally described as a nootropic and neuroprotective agent rather than as a hormone analogue.
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.
Published research on this peptide originates mainly from Russian laboratories, and the wider international literature is comparatively thin. Studies have used rodent models of stroke, hypoxia, and memory tasks, with a smaller number of human trials reported. Reported outcomes include changes in attention and memory measures, along with effects on neurotrophic factor expression in some experiments. Small sample sizes, inconsistent dosing protocols, and limited independent replication are widely noted limitations, so the strength of the clinical evidence remains an open question.
Semax is a synthetic heptapeptide whose sequence is Met-Glu-His-Phe-Pro-Gly-Pro. The first four residues correspond to the ACTH(4-10) fragment, while the terminal Pro-Gly-Pro extension was added to improve metabolic stability. Its molecular formula is C37H51N9O10S and its monoisotopic mass is approximately 813.9 Da. The compound is classified as a peptide research chemical and as a registered pharmaceutical product in Russia, but it does not hold marketing approval in the European Union or the United States. Naming conventions vary across supplier catalogs.
A 15-hydroxyicosatetraenoate dehydrogenase metabolizes 15-hydroxyicosatetraenoic acid (i.e. 15(S)-hydroxy-5Z,8Z,11Z,13E-eicosatetraenoic acid or 15-HETE) to its 15-keto analog, 15-oxo-ETE, using NAD+ and NADH rather than NADP+ and NADPH as its co-factors. 15-Oxo-ETE appears to have a somewhat different spectrum of activities than its precursor, 15-HETE (see 15-Hydroxyicosatetraenoic acid
In 2025, CERN's ALICE experiment team announced that over the previous decade, they had used the Large Hadron Collider to replicate the 2002 SPS mechanisms at higher energies. A total of roughly 260 billion gold nuclei were created over three experimental runs, a minuscule amount of about 90 picograms. Startup Marathon Fusion proposes a theoretical way to make gold from mercury: use a nuclear fusion reactor to bombard mercury with high-energy neutrons, specifically 198Hg, an isotope with 10% abundance. This creates the unstable 197Hg, which then decays into stable gold (197Au) with a half-life of approximately 64 hours.
== Medical uses == Pioglitazone is used to lower blood glucose levels in type 2 diabetes either alone or in combination with sulfonylurea, metformin, or insulin. The effects of pioglitazone have been compared in a Cochrane systematic review to that of other blood sugar lowering-medicine, including metformin, acarbose, and repaglinide, as well as with appropriate diet and exercise, not showing any benefit in reducing the chance of developing type 2 diabetes in people at risk. It did, however, show reduction of risk of developing type 2 diabetes when compared to a placebo or to no treatment. These results should be interpreted considering that most of the data of the studies included in this review were of low or very-low certainty. While pioglitazone does decrease blood sugar levels, the main study that looked at the medication found no difference in the main cardiovascular outcomes that were looked at. The secondary outcome of death from all causes, myocardial infarction, and stroke were lower. Pioglitazone has been found to reduce all-cause mortality in type 2 diabetic patients compared to other therapies, with a 60% reduction in mortality in those exposed to pioglitazone, compared to those never exposed. Another study found an all-cause mortality hazard ratio of 0.33 for pioglitazone after adjusting for >40 covariates, compared to insulin. Due to insufficient data on all-cause mortality, cardiovascular mortality, myocardial infarction and stroke, this was not possible to compare in a more recent review.
Cambrex Corporation is a contract manufacturing organization in the pharmaceutical industry. Cambrex has manufacturing facilities in the US (Agawam, MA; Charles City, IA; Durham, NC; High Point, NC; Longmont, CO; Waltham, MA) and Europe (Edinburgh, UK; Karlskoga, Sweden, Milan, Italy, and R&D centers in Tallinn, Estonia, Wiesbaden, Germany). The headquarters are located in East Rutherford, NJ.
==== Regrowing teeth ==== In 2004, scientists at King's College London discovered a way to cultivate a complete tooth in mice and were able to grow bioengineered teeth stand-alone in the laboratory. Researchers are confident that tooth regeneration technology can be used to grow live teeth in people. In theory, stem cells taken from the patient could be coaxed in the lab turning into a tooth bud which, when implanted in the gums, will give rise to a new tooth, and would be expected to be grown in a time over three weeks. It will fuse with the jawbone and release chemicals that encourage nerves and blood vessels to connect with it. The process is similar to what happens when humans grow their original adult teeth. Many challenges remain, however, before stem cells can be a choice for the replacement of missing teeth in the future.
Sources: en.wikipedia.org
== Publications == Collier was a co-editor of the eighth edition and editor-in-chief of the five-volume ninth edition of the "microbiologist’s bible", Topley and Wilson's Principles of Bacteriology and Immunity (now Topley and Wilson's Microbiology and Microbial Infections), which won the Society of Authors' 1998 award in the advanced edited book category.He was also joint editor of Developments in Antiviral Chemotherapy (1980).He was a co-author of Human Virology (1993).
Radiocarbon dating has established that the shroud is medieval, and not from the time of Jesus. Independent radiocarbon dating tests were carried out in 1988 at the University of Oxford, the University of Arizona and the Swiss Federal Institute of Technology, following years of discussion to obtain permission from the Holy See. The tests were done on portions of a swatch taken from a corner of the shroud, and concluded with 95% confidence that the material dated to AD 1260–1390. The dating matches the first appearance of the shroud in church history. This dating is also slightly more recent than that estimated by the art historian W. S. A. Dale, who postulated on artistic grounds that the shroud is an 11th-century icon made for use in worship services. Some proponents for the authenticity of the shroud have attempted to discount the radiocarbon dating result by claiming that the sample may represent a medieval "invisible mending" repair fragment rather than the image-bearing cloth. However, all of the hypotheses used to challenge the radiocarbon dating have been scientifically refuted, including the medieval repair hypothesis, the bio-contamination hypothesis and the carbon monoxide hypothesis. In recent years, the radiocarbon dating data have been repeatedly statistically analysed in attempts to draw some conclusions about the reliability of the radiocarbon dating from studying the data rather than studying the shroud itself.
=== Relation to beta thalassemia === Delta-beta thalassemia can mask the diagnosis of beta thalassemia trait. In beta thalassemia, an increase in hemoglobin A2 results, but the co-existence of a delta-beta thalassemia mutation will decrease the value of the hemoglobin A2 into the normal range, thereby obscuring the diagnosis of beta thalassemia trait
The particle is modeled by either an electric dipole parallel to the electric field or a pair of crossed electric and magnetic dipoles parallel to the electric and magnetic fields, respectively, of the applied wave. These dipoles are the leading terms in the multipole series. They are the only existing ones for a homogeneous sphere, whose polarizability can be easily obtained from the Mie scattering coefficients. In general, this procedure is known as the "point-dipole approximation", which is a good approximation for metamaterials consisting of composites of electrically small spheres. Merits of these methods include low calculation cost and mathematical simplicity. Three conceptions- negative-index medium, non-reflecting crystal and superlens are foundations of the metamaterial theory. Other first principles techniques for analyzing triply-periodic electromagnetic media may be found in Computing photonic band structure
Disproportionation of an aldehyde in the Cannizzaro reaction Rearrangement of diketones in the benzilic acid rearrangement Involving the generation of benzoic acids are the von Richter reaction from nitrobenzenes and the Kolbe–Schmitt reaction from phenols.
Sources: en.wikipedia.org
Heseltine bought his first Jaguar, second hand and cheap because of the rise in the price of petrol owing to the Suez Crisis, for £1,750 in December 1956, upgrading to newer and more expensive models in future years. New Court Hotel was sold in 1957. At this point Heseltine went into business with another Oxford friend, Clive Labovitch, who brought out Opportunities for Graduates that year. Heseltine arranged for this to be distributed free, expanded from 40 pages to a 169-page hardback book, to final year students at all British universities, paid for by advertising. Heseltine ended his partnership with Josephs and with the aid of a £4,500 investment by Heseltine's mother (following the death of his father in 1957) he and Labovitch were able to buy a group of houses at 29–31 Tregunter Road (south of Earl's Court), adding two more in neighbouring Cathcart Road.
Many cases of hypothyroidism are associated with mild elevations in creatine kinase and liver enzymes in the blood. They typically return to normal when hypothyroidism has been fully treated. Levels of cholesterol, low-density lipoprotein and lipoprotein(a) can be elevated; the impact of subclinical hypothyroidism on lipid parameters is less well-defined. Very severe hypothyroidism and myxedema coma are characteristically associated with low sodium levels in the blood together with elevations in antidiuretic hormone, as well as acute worsening of kidney function due to several causes. For most causes, however, it is unclear if the relationship is causal. A diagnosis of hypothyroidism without any lumps or masses felt within the thyroid gland does not require thyroid imaging; however, if the thyroid feels abnormal, diagnostic imaging is then recommended. The presence of antibodies against thyroid peroxidase (TPO) makes it more likely that thyroid nodules are caused by autoimmune thyroiditis, but if there is any doubt, a needle biopsy may be required.
=== Jiffy === In computing, the jiffy is the duration of one tick of the system timer interrupt. Typically, this time is 0.01 seconds, though in some earlier systems (such as the Commodore 8-bit machines) the jiffy was defined as 1⁄60 of a second, roughly equal to the vertical refresh period (i.e. the field rate) on NTSC video hardware (and the period of AC electric power in North America).
=== High-resolution melting of the entire amplicon === High-resolution melting analysis is the simplest PCR-based method to understand. Basically, the same thermodynamic properties that allowed for the gel techniques to work apply here, and in real-time. A fluorimeter monitors the post-PCR denaturation of the entire dsDNA amplicon. You make primers specific to the site you want to amplify. You "paint" the amplicon with a double-strand specific dye, included in the PCR mix. The ds-specific dye integrates itself into the PCR product. In essence, the entire amplicon becomes a probe. This opens up new possibilities for discovery. Either you position the primers very close to either side of the SNP in question (small amplicon genotyping) or amplify a larger region (100–400bp in length) for scanning purposes. For simple genotyping of an SNP, it is easier to just make the amplicon small to minimize the chances you mistake one SNP for another. The melting temperature (Tm) of the entire amplicon is determined and most homozygotes are sufficiently different (in the better instruments) in Tm to genotype. Heterozygotes are even easier to differentiate because they have heteroduplexes generated (refer to the gel-based explanations) which broadens the melt transition and usually gives two discernible peaks. Amplicon melting using a fluorescently-labeled primer has been described, but is less practical than using ds-specific dyes due to the cost of the fluorogenic primer. Scanning of larger amplicons is based on the same principles as outlined above.
Sources: en.wikipedia.org
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.
Reversed-phase liquid chromatography establishes purity, while mass spectrometry confirms molecular mass. The two techniques are normally used together. Retention time alone is not sufficient evidence of identity.
Different counterions change the mass per unit of peptide and can shift chromatographic behavior. Two samples of equal stated purity may therefore not be directly comparable. Reports should specify the counterion whenever quantitative comparisons are made.
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。