Electrospray ionization 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 2026-02-15. Numbers and descriptions here follow the published literature rather than marketing material.
Common degradation pathways include oxidation of the methionine side chain, hydrolysis of the peptide backbone, and aggregation under unfavourable pH or concentration. Stability studies typically monitor the main peak by chromatography and report total related substances as a percentage. Because no official monograph exists, acceptance criteria vary between laboratories, and reported purity values are not directly comparable across suppliers. Analysts therefore document the method, column, and detection wavelength alongside each result, and open questions remain about how much biological activity the oxidised forms retain.
Solid semax is typically supplied as a lyophilised powder that is hygroscopic and sensitive to moisture, light, and repeated temperature cycling. Long-term storage of the dry peptide is generally recommended at approximately -20 degrees Celsius, while shorter working periods may use refrigeration at 2 to 8 degrees Celsius. Vials should remain tightly closed and desiccated when brought to room temperature, because condensation can damage the material before it is weighed. Dividing a batch into aliquots is preferable to thawing one container repeatedly.
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.
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.
| Property | Value | Notes |
|---|---|---|
| Typical analytical method | Reversed-phase HPLC with UV detection | Separates target peptide from truncated and oxidised forms |
| Identity confirmation | LC-MS or ESI-MS | Compares observed and calculated molecular ion |
| Primary degradation route | Methionine oxidation | Forms the sulfoxide; monitored as an early-eluting peak |
| Short-term storage | 2 to 8 degrees Celsius | Applies to working vials and reconstituted portions |
| Common synonyms | ACTH(4–10) analogue, MEHFPGP | Descriptive names used in laboratory catalogues |
Identity and purity of Semax are established mainly by reversed-phase high-performance liquid chromatography coupled with mass spectrometry. The chromatographic trace gives a purity estimate as a percentage of total peak area, while electrospray or matrix-assisted laser desorption ionization confirms the molecular mass against the calculated value. Amino acid analysis and sequence-specific fragmentation provide further confirmation when a supplier's chain of custody is unclear. Vendors frequently quote a purity figure without stating the detection wavelength or the integration method, which limits how far one number can be compared with another.
Stability depends heavily on physical state. Lyophilized powder held dry, cold and dark retains its content over long periods, whereas dissolved peptide begins to change within days at room temperature. The most cited degradation route is oxidation of the methionine residue, which converts the peptide to a sulfoxide form that elutes differently on chromatography. Hydrolysis of amide bonds and adsorption onto container walls contribute smaller losses. Buffers that exclude oxygen from the headspace slow the oxidation pathway, but no single condition prevents all change indefinitely.
Practical handling follows from those properties. Bulk material is best divided into single-use portions soon after receipt, because each thaw exposes the whole container to moisture and temperature cycling. Vials should be allowed to reach room temperature before opening to prevent condensation on the powder. Low-binding plasticware reduces loss of dilute solutions, and sterile filtration is used when a preparation must remain free of microbial growth. Records of batch number, reconstitution date and storage history are what allow a later analytical result to be interpreted meaningfully.
Semax is a synthetic heptapeptide with the sequence Met-Glu-His-Phe-Pro-Gly-Pro. Its design combines the ACTH(4-7) core fragment with a C-terminal Pro-Gly-Pro extension, a modification intended to improve stability and prolong activity. The molecule is hydrophilic, carries no lipid chains or glycosylation, and has a theoretical mass just over 810 daltons in its free form. All seven residues are proteinogenic amino acids, so no non-natural building blocks appear in the backbone. A free N-terminal methionine and C-terminal proline define the unmodified parent peptide.
The compound was developed during the 1980s at the Institute of Molecular Genetics in Moscow as part of research on fragments of adrenocorticotropic hormone. Early work examined short ACTH-derived sequences that retained neurotrophic effects while lacking the endocrine activity of the full hormone. Semax entered clinical use in Russia during the 1990s, where it received registration for several neurological indications. Outside that region it remained primarily a laboratory research material rather than an approved therapeutic. English-language literature on it grew more slowly and frequently cited the original Russian studies.
Terminology around the compound varies by source. It appears in catalogues and papers as Semax, as the heptapeptide ACTH(4-7)-Pro-Gly-Pro, and under various alphanumeric laboratory codes used by individual suppliers. These names refer to the same sequence but may imply different salt forms, purity grades, or counter-ions. Peptide databases usually list the free base mass, while product descriptions sometimes report acetate or trifluoroacetate salts with a different formula weight. Because naming conventions for research peptides are not standardised across vendors, checking the declared sequence and measured mass is more reliable than relying on a trade name alone.
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.
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。
Al-Qaeda leader Osama bin Laden, who went into hiding in the White Mountains, was targeted by U.S. coalition forces in the Battle of Tora Bora, but he escaped across the Pakistani border and remained out of sight for almost ten years. In an interview with Tayseer Allouni on October 21, 2001, bin Laden stated: The events proved the extent of terrorism that America exercises in the world. Bush stated that the world has to be divided in two: Bush and his supporters, and any country that doesn't get into the global crusade is with the terrorists. What terrorism is clearer than this? Many governments were forced to support this "new terrorism"... America wouldn't live in security until we live it truly in Palestine. This showed the reality of America, which puts Israel's interest above its own people's interest. America won't get out of this crisis until it gets out of the Arabian Peninsula, and until it stops its support of Israel.
=== Metallocenophanes === Metallocenophanes feature linking of the cyclopentadienyl or polyarenyl rings by the introduction of one or more heteroannular bridges. Some of these compounds undergo thermal ring-opening polymerizations to give soluble high molecular weight polymers with transition metals in the polymer backbone. Ansa-metallocenes are derivatives of metallocenes with an intramolecular bridge between the two cyclopentadienyl rings.
=== Pharmacokinetics === In dogs, the absorption of meloxicam from the stomach is not affected by the presence of food, with the peak concentration (Cmax) of meloxicam occurring in the blood 7–8 hours after administration. The half-life of meloxicam is approximately 24 hours in dogs. In the koala (Phascolarctos cinereus), very little meloxicam is absorbed into the blood after oral administration (that is, it has poor bioavailability).
=== April === 2 April – Stand-up comedian Janey Godley wins the inaugural Billy Connolly Spirit of Glasgow Award at the Glasgow International Comedy Festival. 4 April – Data produced by Public Health Scotland indicated that one in three people referred with urgent suspicion of cancer are waiting longer than the target date of 62 days. 5 April – Police arrest former SNP chief executive Peter Murrell as part of their investigation into the party's finances, but release him without charge pending further investigation. 6 April – Following a trial at the High Court in Edinburgh, Kashif Anwar is convicted of the murder of his pregnant wife, Fawziyah Javed, who he pushed from a rocky outcrop on Arthur's Seat, during a holiday in Edinburgh in September 2021. He is sentenced to life imprisonment with a minimum term of 20 years. 7 April BBC News reports that Johnston Carmichael, the accountants who audit the SNP's accounts, have resigned from the role, citing a their decision to do so as having been taken following a review of their clients. The Unite union announces that around 1,300 offshore workers are to stage a 48-hour strike from 24 April over pa, affecting production at dozens of oil and gas platforms. Around 100 workers at Rosyth Dockyard belonging to Unite have voted to strike between 17 April and 10 July in a disagreement with their employers over pay. 8 April – SNP president Mike Russell tells The Herald newspaper he does not think Scottish independence can be achieved "right now", and that the party is facing its biggest crisis for 50 years.
Sources: en.wikipedia.org
=== Area associations (Landschaftsverbände) === The most populous state of North Rhine-Westphalia is uniquely divided into two area associations (Landschaftsverbände), one for the Rhineland, and one for Westphalia-Lippe. This arrangement was meant to ease the friction caused by uniting the two culturally different regions into a single state after World War II. The Landschaftsverbände now have very little power. The constitution of Mecklenburg-Vorpommern at §75 states the right of Mecklenburg and Vorpommern to form Landschaftsverbände, although the old border between these two constituent parts of the state is not represented in the current administrative division.
Several imaging methods can be used to assess the anatomy and function of the heart, including ultrasound (echocardiography), angiography, CT, MRI, and PET, scans. An echocardiogram is an ultrasound of the heart used to measure the heart's function, assess for valve disease, and look for any abnormalities. Echocardiography can be conducted by a probe on the chest (transthoracic), or by a probe in the esophagus (transesophageal). A typical echocardiography report will include information about the width of the valves noting any stenosis, whether there is any backflow of blood (regurgitation) and information about the blood volumes at the end of systole and diastole, including an ejection fraction, which describes how much blood is ejected from the left and right ventricles after systole. Ejection fraction can then be obtained by dividing the volume ejected by the heart (stroke volume) by the volume of the filled heart (end-diastolic volume). Echocardiograms can also be conducted under circumstances when the body is more stressed, in order to examine for signs of lack of blood supply. This cardiac stress test involves either direct exercise, or where this is not possible, injection of a drug such as dobutamine. CT scans, chest X-rays and other forms of imaging can help evaluate the heart's size, evaluate for signs of pulmonary oedema, and indicate whether there is fluid around the heart. They are also useful for evaluating the aorta, the major blood vessel which leaves the heart.
=== Off-targeting === Off-targeting is another challenge to the use of siRNAs as a gene knockdown tool. Here, genes with incomplete complementarity are inadvertently downregulated by the siRNA (in effect, the siRNA acts as a miRNA), leading to problems in data interpretation and potential toxicity. This, however, can be partly addressed by designing appropriate control experiments, and siRNA design algorithms are currently being developed to produce siRNAs free from off-targeting. Genome-wide expression analysis, e.g., by microarray technology, can then be used to verify this and further refine the algorithms. A 2006 paper from the laboratory of Anastasia Khvorova implicates 6- or 7-basepair-long stretches from position 2 onward in the siRNA matching with 3'UTR regions in off-targeted genes. The tool of siRNA off-target prediction is available at http://crdd.osdd.net/servers/aspsirna/asptar.php and published as ASPsiRNA resource.
Sources: en.wikipedia.org
The Austrian public radio station Ö1 Kulturmagazin drew parallels to Kermani's earlier works, noting that its comparative religious metaphysics were also influenced by the question of theodicy. Kermani received the Joseph Breitbach Prize in 2014 for his book Dein Name [Your Name]. and the Thomas Mann Prize in 2024 for his novel Das Alphabet bis S [The Alphabet up to S], which in form and content is a sequel to Dein Name. Advocating for the ideological neutrality of the state Kermani nevertheless criticizes "religious illiteracy" associated with the "complete suppression of religion", which he says leads to a "fundamental spiritual impoverishment of society". Identifying religious tolerance and freedom of religion as important European values, Kermani emphatically calls for the consideration of the beliefs and worldviews of others in the spirit of the Enlightenment. No human being can uncover the ultimate mysteries such as why something exists rather than nothing. According to Kermani, that is why religion came into being in the first place: in it, humans find ways of dealing with what they cannot explain. Religion, then, does not run contrary to the Enlightenment; rather, religion gives expression to what transcends human reason. Kermani notes that precisely to ignore the limits of human reason is what actually constitutes a more anti-Enlightenment stance.
Newborn screening is intended as a public health program to identify infants with treatable conditions before they present clinically, or suffer irreversible damage. Phenylketonuria (PKU) was the first disorder targeted for newborn screening, being implemented in a small number of hospitals and quickly expanding across the United States and the rest of the world. After the success of newborn screening for PKU (39 infants were identified and treated in the first two years of screening, with no false negative results), Guthrie and others looked for other disorders that could be identified and treated in infants, eventually developing bacterial inhibition assays to identify classic galactosemia and maple syrup urine disease. Newborn screening has expanded since the introduction of PKU testing in the 1960s, but can vary greatly between countries. In 2011, the United States screened for 54 conditions, Germany for 12, the United Kingdom for 2 (PKU and medium chain acyl-CoA dehydrogenase deficiency (MCADD)), while France and Hong Kong only screened for one condition (PKU and congenital hypothyroidism, respectively). The conditions included in newborn screening programs around the world vary greatly, based on the legal requirements for screening programs, prevalence of certain diseases within a population, political pressure, and the availability of resources for both testing and follow-up of identified patients.
== Reception == Chain Reaction received negative reviews. The film holds an 18% rating on Rotten Tomatoes based on 33 reviews, with the site's critical consensus stating, "Ironic given the scientific breakthrough at the story's core, Chain Reaction is a man-on-the-run thriller that mostly sticks to [the] generic formula." Audiences polled by CinemaScore gave the film an average grade of "C+" on an A+ to F scale. Roger Ebert gave the film two and a half stars out of four, writing: "By movie's end, I'd seen some swell photography and witnessed some thrilling chase scenes, but when it came to understanding the movie, I didn't have a clue." Jeff Millar of the Houston Chronicle wrote: "The narrative is very complex, but what's on the screen is little more than generic, non-narrative-specific, guy-being-chased stuff". Conversely, Edward Guthmann of the San Francisco Chronicle felt the film was one of the summer's best movies, writing: "[Chain Reaction] has better acting, better writing, more spectacular chase sequences and more genuine drama than all of this summer's blockbusters." Chain Reaction and its cast were nominated for one award, with Keanu Reeves being nominated for the Razzie for Worst Actor, which was won by both Tom Arnold and Pauly Shore. Chain Reaction debuted in fourth place at the box office behind A Time to Kill, Independence Day and Matilda, collecting a total of $7.5 million during its opening weekend. The film grossed just over USD$60.2 million worldwide. Reeves has since expressed regret about Chain Reaction, blaming script changes.
Sources: en.wikipedia.org
Dry powder is usually kept at about -20 degrees Celsius for long-term storage and at 2 to 8 degrees Celsius for short working periods. Containers should stay sealed and protected from light and moisture to limit degradation.
Oxidation of the methionine residue to the sulfoxide is a frequently reported change, and it usually appears as an earlier-eluting peak in reversed-phase chromatography. Backbone hydrolysis products can also accumulate in aqueous solution.
Liquid chromatography coupled with mass spectrometry is the usual approach, because the observed molecular ion can be compared with a calculated mass of about 813.9 Da. Retention time alone does not establish identity.
Semax is based on the ACTH(4-10) fragment, a seven-amino-acid segment of adrenocorticotropic hormone. The synthetic peptide retains the core sequence while removing regions associated with endocrine activity. This modification is intended to isolate effects on the nervous system.