This is a working overview of 反相色谱, written for readers who want more than a one-paragraph summary but less than a textbook.
Reviewed 2026-03-16. Anything still debated is marked as such rather than presented as settled.
Semax is normally supplied as a lyophilized powder, and that form is the most stable. Suppliers commonly recommend storage at -20 °C in a desiccated container protected from light, with short-term handling at room temperature limited to weighing and transfer. Powder that has absorbed moisture degrades faster, so vials should be warmed to ambient temperature before opening to prevent condensation on the contents. Hygroscopic behavior is typical of short hydrophilic peptides, and humidity control matters more than temperature alone for long-term retention.
Once dissolved, the peptide is considerably less stable than the solid. Aqueous solutions are usually prepared at neutral to slightly acidic pH, filtered, and divided into single-use aliquots before freezing. Repeated freeze-thaw cycles are a common cause of avoidable loss and are best prevented by never refreezing a thawed aliquot. Adsorption to plastic and glass surfaces can lower the measured concentration of dilute solutions, particularly below roughly 0.1 mg/mL. Buffer choice, salt content, and container material all influence how much peptide remains detectable after storage.
Identity and purity are established with standard peptide methods. Reversed-phase HPLC with ultraviolet detection near 214 nm resolves the parent peak from deletion and truncation byproducts, and reports typically quote a main-peak percentage. Mass spectrometry by electrospray or MALDI-TOF confirms the expected molecular mass, while amino acid analysis or peptide mapping can verify composition when the sequence itself is in question. A certificate of analysis that pairs a chromatogram with a mass spectrum is more informative than a purity figure alone. Counter-ion content and residual solvents are separate specifications and are frequently omitted.
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.
Published studies are dominated by animal models of stroke, ischemia, and cognitive impairment, with a smaller number of human trials conducted in Russia. Many of the human reports are small, single-center, and published in Russian-language journals, which limits independent scrutiny. Outcome measures vary between studies and often rely on clinician-rated scales rather than objective biomarkers. Systematic reviews have noted the methodological weaknesses and called for larger, preregistered trials before firm conclusions can be drawn.
| Property | Value | Notes |
|---|---|---|
| Solid storage temperature | -20 °C or below | Desiccated and protected from light |
| Solution storage temperature | -80 °C as single-use aliquots | Avoid repeated freeze-thaw cycles |
| Purity assessment method | RP-HPLC, around 214 nm | Reported as main-peak area percent |
| Identity confirmation method | ESI-MS or MALDI-TOF | Measured mass compared with calculated mass |
| Common synonyms | ACTH(4-10) analog; Met-Glu-His-Phe-Pro-Gly-Pro | Also written as Semaxum in some sources |
Routine characterization relies on reversed-phase high-performance liquid chromatography to establish purity and on mass spectrometry to confirm molecular identity. Electrospray ionization and matrix-assisted laser desorption ionization are both used for mass verification. Amino acid analysis and peptide mapping can detect sequence errors. Common impurities include truncated sequences, methionine sulfoxide formed by oxidation, and deamidated products. Chromatograms are usually recorded near 214 nm, where the peptide backbone absorbs, and purity is reported as the percentage area of the principal peak.
Verification of a supplied batch generally combines a certificate of analysis with independent testing, because certificates are self-reported documents. A typical package includes a chromatographic trace, a mass spectrum, and a stated water or counter-ion content. Batch-to-batch consistency matters more than a single purity figure when results are compared across experiments. No single mandatory standard governs research-grade peptide release, so laboratories are expected to define their own acceptance criteria. Residual trifluoroacetate from purification is a frequently overlooked counter-ion.
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.
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.
稳定性主要由水解与氧化两条路径支配。肽键在中性或弱酸性条件下相对稳定，遇到强碱或长时间高温则明显断裂；甲硫氨酸侧链容易被氧化成亚砜，使主峰前移并拉低实际含量。金属离子、光照和反复冻融会进一步促进降解或聚集。冻干粉在低温避光条件下可存放较长时间，配制后的水溶液通常需要冷藏并尽快用完。
纯度评估以反相高效液相色谱为主，通过主峰面积百分比给出粗略结果，再配合电喷雾质谱核对分子量。氨基酸分析可验证组成比例，手性色谱或毛细管电泳用于检查残基构型。常见杂质包括缺失序列的短肽、氧化产物与二聚体。由于多数市售品不附带完整检验报告，独立第三方检测常被用来核实标称值。
=== General election 2015 === During a hustings meeting in Galloway's Bradford West constituency on 8 April during the 2015 general election heated exchanges occurred between Galloway and the Labour candidate, Naz Shah. Galloway accused her of lying about her forced marriage which had been the subject of an open letter written by Shah and released to the media after her selection as a candidate. He said Shah was in error in claiming she was "subject to a forced marriage at the age of 15. But you were not 15. You were 16-and-a-half". He then produced what he said was her nikah, a Muslim marriage certificate. Shah alleged at the event that Galloway's representative in Pakistan impersonated her deceased father to acquire the nikah. Ron McKay, Galloway's spokesman, said that there was no dishonesty in gaining access to the document via an intermediary in Pakistan. Labour supplied media outlets with a copy of Shah's nikah which confirms that she was 15 at the time of her forced marriage. By her own account, Shah was raped during the marriage, but in an email to Helen Pidd, The Guardian's northern editor, McKay disputed that it had been a forced marriage at all. Galloway accused Shah of favouring Israel. At one point during the campaign, Galloway tweeted a picture of Israelis waving Israeli flags with the caption "Thank you for electing Naz Shah". The image was juxtaposed with another, showing Palestinians celebrating his own supposedly imminent victory. Shah said she has participated in marches supporting the Palestinian cause.
Hydroxymethylfurfural (HMF), also known as 5-(hydroxymethyl)furfural, is an organic compound formed by the dehydration of reducing sugars. It is a white low-melting solid (although commercial samples are often yellow) which is highly soluble in both water and organic solvents. The molecule consists of a furan ring, containing both aldehyde and alcohol functional groups. HMF can form in sugar-containing food, particularly as a result of heating or cooking. Its formation has been the topic of significant study as HMF was regarded as being potentially carcinogenic to humans. However, so far in vivo genotoxicity was negative. No relevance for humans concerning carcinogenic and genotoxic effects can be derived. HMF is classified as a food improvement agent and is primarily being used in the food industry in form of a food additive as a biomarker as well as a flavoring agent for food products. It is also produced industrially on a modest scale as a carbon-neutral feedstock for the production of fuels and other chemicals.
5'-end Also five-prime end. One of two ends of a single linear strand of DNA or RNA, specifically the end at which the chain of nucleotides terminates at the fifth carbon atom in the furanose ring of deoxyribose or ribose (i.e. the terminus at which the 5' carbon is not attached to another nucleotide via a phosphodiester bond; in vivo, the 5' carbon is often still bonded to a phosphate group). By convention, sequences and structures positioned nearer to the 5'-end relative to others are referred to as upstream. Contrast 3'-end.
Sources: en.wikipedia.org
Asprosin is a fasting-induced hormone encoded by the FBN1 gene and derived from the cleavage of the fibrillin-1 protein, a structural component of the extracellular matrix. It is primarily produced and secreted by white adipose tissue. As a peripherally derived hormone, asprosin actively crosses the blood-brain barrier (BBB) to exert central effects on metabolic and behavioral regulation. It stimulates the liver to release glucose into the bloodstream during fasting, ensuring energy availability, and influences appetite and body weight regulation by acting on hypothalamic neurons. Dysregulation of asprosin levels has been implicated in metabolic disorders such as obesity and diabetes, making it a promising target for therapeutic interventions.
The Knights Templar Cartel (Spanish: Caballeros Templarios) was created in Michoacán in 2011 after the presumed death of the leader of La Familia Michoacana, Nazario Moreno González. The cartel was headed by Enrique Plancarte Solís and Servando Gómez Martínez ("La Tuta"), who formed the Knights Templar due to differences with José de Jesús Méndez Vargas, who had assumed leadership of La Familia Michoacana. The cartel was reported to promote a religious doctrine as part of its identity. Sizable battles flared up in 2011 between the Knights Templar and La Familia. The organization grew from a splinter group to a dominant force in Michoacán, and following the arrest of Méndez Vargas, the cartel appeared to have taken over the bulk of La Familia's operations. In 2011 the Knights Templar appeared to have aligned with the Sinaloa Federation in an effort to root out the remnants of La Familia and to prevent Los Zetas from gaining foothold in the Michoacán region. In 2014 Plancarte Solís was killed by the Mexican Navy, and Gómez Martínez was arrested in 2015. The cartel is believed to have disbanded in 2017.
Leonidas Zervas (Greek: Λεωνίδας Ζέρβας, pronounced [leoˈniðas ˈzervas]; 21 May 1902 – 10 July 1980) was a Greek organic chemist who made seminal contributions in peptide chemical synthesis. Together with his mentor Max Bergmann they laid the foundations for the field in 1932 with their major discovery, the Bergmann-Zervas carboxybenzoxy oligopeptide synthesis which remained unsurpassed in utility for the next two decades. The carboxybenzyl protecting group he discovered is often abbreviated Z in his honour. Throughout his life Zervas also served in many important posts, including President of the Academy of Athens or briefly Minister of Industry of Greece. He received numerous awards and honours during his life and posthumously, such as Foreign Member of the USSR Academy of Sciences or the first Max Bergmann golden medal.
Indeed, at least four people have died in the course of either preparation for or institution of bone marrow transplantation for EB, out of only a small group of patients treated so far. The mechanism of action of this therapy is unclear as hematopoietic stem cells are not thought to contribute to epithelial lineages. Rather, it is speculated that cross-correction from tissue-resident graft-derived immune cells contributes to the observed clinical benefit. A pilot study performed in 2015 suggests that systemic granulocyte-colony stimulating factor (G-CSF) may promote increased wound healing in people with dystrophic EB. Transplanting skin derived from genetically modified stem cells onto the wound surfaces has been studied with a report of improvements in one person. A 2017 clinical trial with male RDEB (recessive dystrophic EB) patients conducted successful grafting of type VII gene corrected keratinocytes (COL7A1 gene correction using retrovirus transduction), without any serious adverse effects. Type VII collage formation was observed at the dermis-epidermis junction in significant amounts. A 2020 study demonstrated the safe allogenic grafting of acellular dermal matrix/scaffolds in EB patients without any observed infection or necrosis and instead noted fewer required dressing changes, promoted wound healing, pain reduction, and an overall improvement in the quality of life of the patients. In 2022, a pharmaceutical gel made out of birch bark extract from Betula pendula and Betula pubescens was approved by the European Union as a treatment for epidermolysis bullosa.
Sources: en.wikipedia.org
As of 2025, Biden was the oldest sitting president in U.S. history. His cognitive health was perceived to have declined by Republicans and some media figures, and privately by some Democrats. Members of Biden's family and White House staffers insulated Biden from scrutiny of his advanced aging and decline in acuity. The media widely covered public concern about Biden's mental acuity after a weak performance in a June 2024 presidential debate, but gave it limited coverage beforehand, in part due to harsh pushback from White House officials. Biden initially deemed himself fit to serve two terms as president, but after the 2024 election said that he may have been too old to serve a second term. As part of the investigation into Biden's handling of classified documents, special counsel Robert Hur said that Biden did not remember when he was vice president ("if it was 2013—when did I stop being vice president?") or when his son Beau died. Hur wrote that his memory "appeared to have significant limitations". On July 21, 2022, Biden tested positive for COVID-19 with reportedly mild symptoms. According to the White House, he was treated with Paxlovid. He worked in isolation in the White House for five days and returned to isolation when he tested positive again on July 30. On July 17, 2024, Biden again tested positive for COVID-19.
It's the only antipsychotic that's demonstrated efficacy as a monotherapy for the treatment of major depressive disorder and bipolar disorder (it treats mixed mood swings alone). It indirectly serves as a norepinephrine reuptake inhibitor by means of its active metabolite, norquetiapine. Zotepine – Of the dibenzothiepin class of atypical antipsychotic indicated for acute and chronic schizophrenia. It is still used in Japan and was once used in Germany but it was discontinued.†
These metabolites are not detected in urine and, if formed, are likely excreted in bile or rapidly converted into thiotepa-mercapturate. Additionally, due to its high lipophilicity, thiotepa is excreted in minor amounts by the skin via sweat.
== Classification == The MEROPS protease classification system counts 14 superfamilies plus several currently unassigned families (as of 2013) each containing many families. Each superfamily uses the catalytic triad or dyad in a different protein fold and so represent convergent evolution of the catalytic mechanism. For superfamilies, P indicates a superfamily containing a mixture of nucleophile class families, and C indicates purely cysteine proteases. Within each superfamily, families are designated by their catalytic nucleophile (C denoting cysteine proteases).
is the fourth-order tensor representing the constant of proportionality, called the viscosity or elasticity tensor, and : is the double-dot product. the fluid is assumed to be isotropic, as with gases and simple liquids, and consequently
Sources: en.wikipedia.org
Each freeze-thaw cycle can degrade a fraction of the peptide and promote aggregation. Dividing a stock solution into single-use volumes removes repeated cycling as a variable. It also limits the time a thawed solution spends at room temperature.
A high main-peak percentage says little about identity, counter-ion content, or residual solvents. It also does not distinguish an isomer or a closely eluting analog. Mass confirmation and the accompanying documentation cover those gaps.
Salt form changes mass, solubility, and hygroscopicity, and acetate and trifluoroacetate salts behave differently in solution. Storage guidance still centers on -20 °C for powder and lower temperatures for solutions. The certificate should state which salt is present.
It is associated with the melanocortin receptor family, particularly subtypes found in the central nervous system. This interaction is separate from the adrenal pathway activated by full-length ACTH.