This is a working overview of 非天然氨基酸, written for readers who want more than a one-paragraph summary but less than a textbook.
Reviewed 2026-08-01. Anything still debated is marked as such rather than presented as settled.
Compared with other secretagogues such as GHRP-2, GHRP-6, and hexarelin, ipamorelin is described as more selective. Published animal work reports little or no increase in adrenocorticotropic hormone, cortisol, or prolactin at doses that release growth hormone. This selectivity is the property most often cited in the research literature. Whether the same profile holds across species and dosing schedules remains an open question, since human data are limited and come largely from small studies.
Ipamorelin is a synthetic pentapeptide that belongs to the growth hormone secretagogue family. Its sequence is Aib-His-D-2-Nal-D-Phe-Lys-NH2, and its molecular mass is approximately 711.9 daltons. The compound was described in the late 1990s by researchers seeking molecules that release growth hormone with fewer side effects than earlier secretagogues. It is a laboratory and research compound, not an approved medicine in most jurisdictions.
At the molecular level, ipamorelin acts as an agonist at the growth hormone secretagogue receptor, also called the ghrelin receptor or GHS-R1a. Binding to this receptor on pituitary somatotroph cells triggers a signaling cascade that leads to growth hormone release. The effect is mediated through phospholipase C and calcium mobilization rather than through the cyclic AMP pathway used by growth hormone releasing hormone. The two pathways are complementary, and combined stimulation produces a larger response than either alone.
从用途定位看，ipamorelin 目前主要以研究用肽的身份被讨论，未见主要药品监管机构将其批准为治疗药物。市售材料通常标注仅供研究使用，不得用于人体或诊断程序。文献中它常与生长激素促分泌素、GHS-R1a 激动剂、胃饥饿素拟似物等表述并列出现。既有研究的样本量普遍偏小，因此对其效应强度与一致性的描述应保持谨慎。
Ipamorelin 是一种合成五肽，序列为 Aib-His-D-2-Nal-D-Phe-Lys-NH2，分子式 C38H49N9O5，游离碱分子量约 711.85 g/mol。它属于生长激素促分泌素（GHS）家族，作用靶点是胃饥饿素受体 GHS-R1a。该化合物由诺和诺德的研究团队在二十世纪九十年代末报道，设计目标是提高对生长激素释放的选择性。C 端酰胺化与 N 端 Aib 残基是两个用于抵抗肽酶降解的结构特征。
| Property | Value | Notes |
|---|---|---|
| Chemical class | Synthetic pentapeptide | Growth hormone secretagogue family |
| Molecular mass | Approximately 711.9 Da | Free base, calculated value |
| Receptor target | GHS-R1a, the ghrelin receptor | Agonist activity reported |
| Sequence | Aib-His-D-2-Nal-D-Phe-Lys-NH2 | C-terminal amide |
| Reported selectivity | Little change in ACTH, cortisol, prolactin | Based mainly on animal data |
Common solvents for laboratory work include water, buffered saline, and dimethyl sulfoxide. Once dissolved, the peptide is exposed to hydrolysis and oxidation, and alkaline conditions accelerate breakdown. Low-binding plasticware and the addition of a carrier protein reduce losses to container surfaces, which can otherwise be substantial at low concentrations. Solutions are typically kept cold and used within days. Investigators working with the compound generally prepare fresh working dilutions rather than storing dilute stocks, and they avoid repeated warming of the same vial.
Reversed-phase high-performance liquid chromatography is the standard method for purity assessment, most often on a C18 column with a water and acetonitrile gradient and trifluoroacetic acid or formic acid as an ion-pairing agent. Mass spectrometry by electrospray or matrix-assisted laser desorption confirms the expected mass and reveals truncated or modified sequences. Amino acid analysis and sequencing provide orthogonal structural evidence. Typical impurities include deletion sequences, oxidized products, and dimeric species. Detection wavelength, usually 214 or 220 nanometers, should be reported because response factors differ between peptides.
Purity is normally reported as a percentage of total peak area, a figure that does not account for water content, residual solvents, or counterions. Trifluoroacetate and acetate are the most frequent counterions in lyophilized peptides, and they shift the true peptide content away from the mass of the powder. A separate quantitative assay is therefore needed to state content accurately. Certificates of analysis often omit these details, which makes batch-to-batch comparison difficult and limits conclusions drawn when results from different suppliers are compared.
In animal and early human studies, ipamorelin produces pulsatile growth hormone release and a secondary rise in insulin-like growth factor 1. The magnitude and duration of that rise depend on route, sampling schedule, and the baseline endocrine state of the subject. Whether repeated exposure alters the response over time is not firmly settled, since some reports describe stable pulsatility while others note attenuation. Most published data come from small samples, which limits the strength of any general claim about long-term behavior.
Ipamorelin is a synthetic pentapeptide that belongs to the growth hormone secretagogue class of compounds. Its sequence is Aib-His-D-2-Nal-D-Phe-Lys-NH2, a structure that differs from natural ghrelin in length and in the presence of non-natural amino acid residues. Early laboratory work described it as a comparatively selective agent that stimulates growth hormone release with limited effect on other pituitary hormones. The compound is supplied as a lyophilized solid for research use and has no identified natural source in the body.
Activity is mediated mainly through the growth hormone secretagogue receptor, now generally called the ghrelin receptor or GHS-R1a. Binding at this G-protein-coupled receptor triggers phospholipase C signaling, calcium mobilization, and release of growth hormone from pituitary somatotrophs. Reports describe less pronounced stimulation of adrenocorticotropic hormone and prolactin compared with earlier secretagogues such as hexarelin or GHRP-6. Selectivity figures vary between assay systems, so the degree of separation from other secretagogues is an area of ongoing comparison rather than a fixed constant.
=== In epithelial tumors === Clear cell renal cell carcinoma (Clear cell RCC) CD10+ distinguishes renal cell carcinoma, conventional type with eosinophilic morphology from its mimickers. Chromophobe carcinoma and oncocytoma are CD10−. Pancreatic tumors Solid pseudopapillary tumours are CD10+. CD10+ differentiates mucinous cystic neoplasms (CD10+/CK20+) from intraductal papillary mucinous neoplasm of branch duct type (CD10−/CK20-). Cutaneous tumors CD10 may differentiate basal cell carcinoma (CD10 epithelial staining) from trichoblastoma (CD10 peritumoral stromal staining), basal cell carcinoma with follicular differentiation (CD10 stromal and epithelial staining) and squamous cell carcinoma (strong stromal staining). CD10 differentiates CD10+ atypical fibroxanthoma from CD10− spindle cell melanoma and sarcomatoid squamous cell carcinoma. Urothelial tumors express CD10 (42-67%). CD10 expression is strongly correlated with high tumor grade and stage in urothelial carcinoma of the bladder. CD10 may be associated with tumor progression in bladder cancer pathogenesis.
Negros has a lot of tourist attractions. In the city of Silay alone, there are 30 ancestral houses, amongst the most notable is the Balay Negrense. Festivals are also a major tourist attraction in Negros. Among the most notable is the Masskara Festival in the city of Bacolod, which is celebrated during the third week of October, as well as Buglasan Festival in the city of Dumaguete, also held in October. Museums showcase the culture, history and people of Negros, with one example being the Negros Museum, situated behind the Negros Occidental Provincial Capitol Complex. Murcia and Don Salvador Benedicto offer experiences in inland Negros Occidental, the former being known for its Mambukal Resort, while the latter serves as the "Summer Capital of Negros Occidental". Kanlaon Volcano, as well as many other neighbouring peaks, are popular amongst mountain climbers and hikers visiting Negros. The town of Pulupandan, situated in the western tip of Negros, is becoming popular to bird-watching enthusiasts. thanks to its new bird-watching sanctuary. When it comes to beaches and coastal resorts within the region, the most popular ones are Lakawon Island in Cadiz, Jomabo Island in Escalante, Sipaway/Refugio Island in the city of San Carlos, Sipalay, Hinoba-an and Manjuyod's sand bar. The top attractions in Cauayan are the Punta Bulata White Beach Resort and Danjugan Island, which serves as a major diving spot in Negros Occidental.
=== Soil === Isolates from coal power plant soil are being recognized as pseudomonas and show that they are able to “grow on both the aliphatic and aromatic fractions of petroleum". The aliphatic fraction accounts for the most of crude oil and it is easily broken down by species of pseudomonas. Concentration of naphthene and aromatics components of crude oil noticeably decreased, implying the catabolic flexibleness of pseudomonas isolates. Salam, Obayori, Akashoro, and Okogie say that with incubation of pseudomonas isolates at 1g/L concentration for 21days, 90% of BLCO was broken down which means almost all of aliphatic fragments were vanished and aromatic fragments remarkably decreased. Although there are some microorganisms which are able to degrade crude oil, pseudomonas group shows up as it is the most adaptable. There are two main seasons which are dry and rainy in Nigeria. In the dry season, the temperature of soil varies between 30 and 45 °C, while it changes from 20 to 30 °C during the dry season. The ability of bacteria in soil to break down crude oil is remarkably affected by the average temperatures, pH, and nutrients in the soil that are quite different by seasons. For the experiment that is conducted incubation of Pseudomonas sp and Bacillus sp at the different temperature from 20 to 44 °C and for different time from 6 to 24days, both of bacteria showed the highest amount of degradation of bonny light oil at 36 °C. The amount of degradation of crude oil diversified according to the temperature.
Aminoacylation is the process of adding an aminoacyl group to a compound. It covalently links an amino acid to the CCA 3′ end of a tRNA molecule. Each tRNA is aminoacylated (or charged) with a specific amino acid by an aminoacyl tRNA synthetase. There is normally a single aminoacyl tRNA synthetase for each amino acid, despite the fact that there can be more than one tRNA, and more than one anticodon for an amino acid. Recognition of the appropriate tRNA by the synthetases is not mediated solely by the anticodon, and the acceptor stem often plays a prominent role. Reaction:
Staley's mother, Nancy McCallum, told The Seattle Times in 2007 that despite his isolation, he was never far from the love of his family and friends, who filled his answering machine and mailbox with messages and letters. "Just because he was isolated doesn't mean we didn't have sweet moments with him." McCallum has also claimed that she saw Staley on Thanksgiving of 2001, and again just around Valentine's Day of 2002, when he visited his sister's baby. This was the last time that McCallum saw her son. Sean Kinney has commented on Staley's final years and isolation period:
Sources: en.wikipedia.org
== Rice == From 2009 to 2019, Thailand's hom mali 105 (jasmine) rice has been declared the world's best rice five times. But in 2018, Cambodian Malys Angkor jasmine rice was the winner, and Vietnam's ST24 rice took top honours in 2019, causing panic among Thai rice producers as ST24 is half the price of Thai hom mali.
=== Systematics === The emu was long classified, with its closest relatives the cassowaries, in the family Casuariidae, part of the ratite order Struthioniformes. An alternate classification was proposed in 2014 by Mitchell et al., based on analysis of mitochondrial DNA. This splits off the Casuariidae into their own order, the Casuariiformes, and includes only the cassowaries in the family Casuariidae, placing the emus in their own family, Dromaiidae. The cladogram shown below is from their study.
The enzyme characterised from Aspergillus niger and mammalian liver hydrolyses nicotinamide to nicotinic acid and ammonia. This reaction is part of the salvage pathway for nicotinamide adenine dinucleotide. Inhibition of the enzyme has been suggested as a mechanism of insect control. The prodrug, pyrazinamide, is converted into the bacteriostatic pyrazinoic acid by this enzyme in Mycobacterium tuberculosis. This enzyme is a hydrolase, one acting on carbon-nitrogen bonds other than peptide bonds, specifically in linear amides. The systematic name of this enzyme class is nicotinamide amidohydrolase. Other names in common use include nicotinamide deaminase, nicotinamide amidase, and YNDase.
Because bacteria are prokaryotes, they are not equipped with the full enzymatic machinery to accomplish the required post-translational modifications or molecular folding. Hence, multi-domain eukaryotic proteins expressed in bacteria often are non-functional. Also, many proteins become insoluble as inclusion bodies that are difficult to recover without harsh denaturants and subsequent cumbersome protein-refolding. To address these concerns, expressions systems using multiple eukaryotic cells were developed for applications requiring the proteins be conformed as in, or closer to eukaryotic organisms: cells of plants (i.e. tobacco), of insects or mammalians (i.e. bovines) are transfected with genes and cultured in suspension and even as tissues or whole organisms, to produce fully folded proteins. Mammalian in vivo expression systems have however low yield and other limitations (time-consuming, toxicity to host cells,..). To combine the high yield/productivity and scalable protein features of bacteria and yeast, and advanced epigenetic features of plants, insects and mammalians systems, other protein production systems are developed using unicellular eukaryotes (i.e. non-pathogenic 'Leishmania' cells).
However, all types of van der Waals forces are ultimately of electrostatic origin and therefore depend on dielectric properties of the environment. The direct measurement of attraction forces between different materials (as Hamaker constant) shows that "the interaction between hydrocarbons across water is about 10% of that across vacuum". The environment-dependence of van der Waals forces is neglected in standard simulations, but can be included by developing polarizable force fields.
Sources: en.wikipedia.org
=== 2016–2025: Hayden leadership === Appointed in 2016 by President Barack Obama, Carla D. Hayden was sworn in as the fourteenth librarian of Congress on September 14, 2016. She is the first professional librarian to hold the post since 1974, holding a Ph.D. in library science from the University of Chicago. She was the CEO of Enoch Pratt Free Library in Baltimore, Maryland, from 1993 until 2016, and president of the American Library Association (ALA) from 2003 to 2004. She also is the first woman and the first African American to hold the position. She continued the work of digitizing as much as possible of the collection and of expanding electronic access to the collection. She initiated programs to modernize the library, expand access from rural areas, and expanding the infrastructure and technological capacity of the library and assessment of her leadership of the library by the community reflects her expressed goals. The Association of Research Libraries noted Hayden's transformation of the library "into a more open, accessible, and celebrated U.S. institution, while reaffirming its role as the people’s library". The American Library Association characterized Hayden as a "wise and faithful steward of the Library of Congress – the library she has called our 'national treasure'".
The normal rhythmical heart beat, called sinus rhythm, is established by the heart's own pacemaker, the sinoatrial node (also known as the sinus node or the SA node). Here an electrical signal is created that travels through the heart, causing the heart muscle to contract. The sinoatrial node is found in the upper part of the right atrium near to the junction with the superior vena cava. The electrical signal generated by the sinoatrial node travels through the right atrium in a radial way that is not completely understood. It travels to the left atrium via Bachmann's bundle, such that the muscles of the left and right atria contract together. The signal then travels to the atrioventricular node. This is found at the bottom of the right atrium in the atrioventricular septum, the boundary between the right atrium and the left ventricle. The septum is part of the cardiac skeleton, tissue within the heart that the electrical signal cannot pass through, which forces the signal to pass through the atrioventricular node only. The signal then travels along the bundle of His to left and right bundle branches through to the ventricles of the heart. In the ventricles the signal is carried by specialized tissue called the Purkinje fibers which then transmit the electric charge to the heart muscle.
=== Pharmacokinetics === Gepotidacin is rapidly absorbed orally, reaching peak plasma concentrations (tmax) after approximately 2.0 hours. In adults with uncomplicated urinary tract infections (uUTI) and normal renal function, the mean steady-state maximum concentration (Cmax) is 4.2 mcg/mL, and the area under the concentration-time curve over 12 hours AUC(0-12) is 22.8 mcg*hour/mL following a 1500 mg dose every 12 hours. Systemic exposure (Cmax and AUC) increases proportionally with dose. Accumulation of approximately 40% occurs and achieves a steady state by day 3. The absolute bioavailability is about 45%, and standard and moderate fat meals did not significantly affect its absorption. Gepotidacin's pharmacokinetics were found to be generally consistent across different ages, sexes, races, and body weights during modeling and simulation. Gepotidacin has a mean steady-state volume of distribution (Vss) of 172.9 liters and is 25-41% bound to plasma proteins. It has a terminal elimination half-life of approximately 9.3 hours and a total clearance of 33.4 L/hour. The primary metabolic pathway involves CYP3A4, with a minor metabolite (M4, ~11% of circulating drug). The co-administration of other drugs can influence gepotidacin levels. Strong inhibitors of CYP3A4 can increase gepotidacin exposure, whereas strong inducers of CYP3A4 can decrease it. Additionally, gepotidacin, at high concentrations, has shown the potential to increase the exposure of certain other drugs, including digoxin and midazolam.
=== CSIR India === In 2009, Ayyadurai was hired by India's Council of Scientific and Industrial Research (CSIR), India's largest science agency, by its director general, Samir K. Brahmachari. CSIR was mandated to create a new company, CSIR Tech, that would establish businesses using the research conducted by the country's many publicly owned laboratories. Ayyadurai reported that he had spent months trying to create a business plan for CSIR Tech, but received no response from Brahmachari. Ayyadurai then distributed a draft plan, which was not authorized by CSIR, to the agency's scientists that requested feedback and criticized management. His job offer was subsequently withdrawn five months after the position was offered. Brahmachari said that "the offer was withdrawn as [Ayyadurai] did not accept the terms and conditions and demanded unreasonable compensation." In its report, The New York Times said that "going public with such accusations is highly unusual. Mr. Ayyadurai circulated his paper not just to the agency's scientists but to journalists, and wrote about his situation to Prime Minister Manmohan Singh." In that letter, Ayyadurai said his report was intended to explore institutional barriers to CSIR's entrepreneurial mandate. He said that CSIR scientists reported that "they work in a medieval, feudal environment" that required a "major overhaul". The letter was co-authored by a colleague, Deepak Sardana.
== Treatment == Treatment is the same as for patients with sickle cell disease. Patients may receive hydroxyurea to induce the protective effects of increased fetal hemoglobin production. They may also benefit from blood transfusions especially during vaso-occlusive crises. Patients may be offered chemoprophylaxis with penicillin. They may have splenic dysfunction and splenectomy is frequently performed. Vaccination against encapsulated bacteria including Streptococcus pneumoniae is recommended.
Sources: en.wikipedia.org
Ipamorelin is a synthetic pentapeptide that stimulates growth hormone release by activating the ghrelin receptor. It is handled as a research tool rather than as a licensed therapeutic product. Its short chain length makes it comparatively simple to synthesize and analyze.
Both bind the same receptor, but ghrelin is a 28-amino-acid hormone with roles in appetite and energy balance. Ipamorelin is a much smaller synthetic peptide selected for growth hormone release with limited effect on appetite signaling in animal models. The full overlap between their effects is not completely mapped.
Most published data come from animal studies and a small number of human trials. Findings on growth hormone release are reasonably consistent, while long-term effects and direct comparisons with other secretagogues remain incompletely studied. Open questions include duration of action across different populations.
两者都是 GHS-R1a 激动剂，但 ipamorelin 在研究中显示出更高的生长激素释放选择性。早期资料显示它对皮质醇、催乳素与食欲的刺激弱于 GHRP-6。这些差异是相对程度，而非绝对区分。