The short version of secretagogue fits in a sentence. The long version — which is the one that helps — is below.
Reviewed 2026-03-12. Anything still debated is marked as such rather than presented as settled.
杂质谱一般包含缺失序列片段、差向异构体、氧化产物以及残留溶剂或反离子，其中组氨酸与芳香残基的氧化常被重点关注。反相色谱中这类杂质往往紧邻主峰洗脱，因此方法需要足够的分离度并经过系统适用性验证。纯度百分比的解读依赖于检测波长与梯度条件，不同实验室公布的数字不宜直接横向比较。参考标准品有助于跨批次对照，但其自身赋值同样需要可追溯来源。
冻干状态下的肽通常比溶液状态更稳定，常规做法是维持 -20 °C 或更低温度、保持干燥并避开强光。复溶后的降解主要来自水解、氧化与脱酰胺，速率受 pH、缓冲液种类、离子强度与温度共同影响，碱性条件一般会加快这些反应。反复冻融会造成聚集与容器吸附损失，分装保存能降低该风险。容器材质与金属离子也可能参与氧化过程，需与操作条件一并考虑。
对 ipamorelin 的常规表征以反相高效液相色谱测定纯度，检测波长多设为 214 nm，因为肽键在该波长有较强吸收。身份确认通常借助电喷雾电离质谱或串联质谱，将实测分子量与理论值逐项比对。序列层面可用肽图分析或氨基酸分析进一步验证。这些手段组合起来，可以分别覆盖纯度、身份与序列三个不同层次的信息。
The molecule contains five residues, including alpha-aminoisobutyric acid, D-2-naphthylalanine, and D-phenylalanine, and it ends in a lysine amide. Non-natural and D-configured residues make the chain less susceptible to common peptidases, which helps explain its resistance to rapid breakdown. Its molecular formula is C38H49N9O5, corresponding to a free-base mass near 711.9 daltons. The C-terminal amide removes a negative charge and is a recurring feature in receptor-active peptides of this family. These structural choices are usually discussed as the basis for its selectivity profile.
Published animal and early human work describes growth hormone release that is separated from comparable rises in adrenocorticotropic hormone and cortisol. Prolactin changes are reported as small in the same studies. Selectivity is attributed to binding at the ghrelin receptor and to the downstream signaling that follows, rather than to differences in how quickly the peptide is cleared. Authors commonly label the compound selective rather than potent, because the same mass produces a smaller growth hormone response than some older secretagogues tested in parallel. Whether that profile holds across species and routes of administration remains an open question.
| Property | Value | Notes |
|---|---|---|
| 纯度检测 | RP-HPLC，214 nm | 乙腈/水梯度，含 0.1% 三氟乙酸 |
| 身份确认 | ESI-MS 或 LC-MS/MS | 比对实测与理论分子量 |
| 冻干粉储存 | -20 °C，干燥避光 | 分装可减少开盖次数 |
| 复溶液储存 | 2-8 °C，短期使用 | 避免反复冻融与长时间室温放置 |
| 主要降解途径 | 水解、氧化、脱酰胺 | 碱性 pH 与强光会加快反应 |
Identity and purity are assessed by complementary methods rather than a single test. Reversed-phase high-performance liquid chromatography separates the peptide from related impurities and reports a percentage purity. Mass spectrometry, most often with electrospray ionization, confirms the expected molecular mass and detects sequence-related variants. Amino acid analysis can verify composition, while water content and residual counterion measurements support the mass balance of a batch. Stability studies under accelerated conditions are used to estimate shelf life, though such estimates carry uncertainty for long-term storage.
Material supplied for research use is normally a white to off-white lyophilized powder. The solid is hygroscopic and is handled in a low-humidity environment to limit water uptake. Bulk quantities are frequently shipped in sealed vials under inert gas. Once reconstituted in water or a neutral buffer, the solution is less stable than the dry powder and is usually divided into single-use aliquots.
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 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.
Structural features distinguish the molecule from earlier secretagogues. An alpha-aminoisobutyric acid residue near the N-terminus and a D-naphthylalanine substitution increase receptor affinity, while C-terminal amidation improves resistance to exopeptidases. These modifications are associated with reduced stimulation of appetite and of the hypothalamic-pituitary-adrenal axis compared with hexarelin or growth hormone releasing peptide-6. Whether the same profile applies at every dose level studied is a matter of ongoing investigation rather than settled consensus.
Ipamorelin is a synthetic pentapeptide that acts as an agonist at the ghrelin receptor, also called the growth hormone secretagogue receptor type 1a. Its sequence incorporates non-natural residues, which slows enzymatic breakdown relative to short native peptides. In laboratory and early clinical work the compound is described as a selective growth hormone secretagogue because it raises growth hormone with comparatively little effect on other pituitary outputs. The degree to which that selectivity holds across species and dosing regimens remains an open question in the published literature.
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.
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.
Americium-241 often enters landfills from discarded smoke detectors. The rules associated with the disposal of smoke detectors are relaxed in most jurisdictions. In the U.S., the "Radioactive Boy Scout" David Hahn was able to concentrate americium-241 from smoke detectors after managing to buy a hundred of them at remainder prices and also stealing a few. There have been a few cases of exposure to americium-241, the worst being Harold McCluskey who, at age 64, was exposed to 500 times the occupational standard for americium-241 as a result of an explosion in his lab. McCluskey died at age 75, not as a result of exposure, but of a heart disease which he had before the accident. Americium-241 has also been detected in the oceans as a result of nuclear testing conducted by various nations.
=== Natural Metalloenzymes repurposing === In addition to anchoring artificial metal center in the protein scaffold, researchers like Frances Arnold and Yang Yang focused on changing the native environment of natural metallocofactors. Due to the large sequence space that can be evolved in natural metalloenzymes, they can be evolved to catalyse non-native transformations. This process is known as enzyme repurposing. Directed evolution is commonly used to tailor the catalytic capacity and repurpose the enzyme function. Mostly based on native porphyrin-metallocofactor, Arnold's lab has developed many ArMs catalysing regioselective and/or enantioselective transformations, such as Carbon-Boron bond formation, carbene insertion, and aminohydroxylation by evolving the sequence context of the corresponding ArMs. As the pioneers of metalloredox radical biocatalysis, Yang et al. repurposed cytochrome P450s to catalyze atom transfer radical cyclization (ATRC), and Huang et al. repurposed non-heme Fe-dependent enzymes to catalyze an abiological radical-relay azidation and radical fluorination.
== Menu == Jimmy John's has three bread options: French, thick-sliced wheat, and the six-inch "Lil' John" (smaller version of French bread), as well as a lettuce-wrap option known as the Unwich, and a tortilla-wrap option. Jimmy John's has 17 different numbered sandwiches plus a B.L.T., called the J.J.B.L.T, and the Gargantuan, which includes all the meats except bacon and tuna. The 17 sandwiches may have ham, roast beef, tuna, turkey, salami, capicola, bacon, provolone cheese or parmesan cheese, or combine two or more meats and cheese. Jimmy John's has four flavors of chips, including regular, BBQ, jalapeño, and salt and vinegar. The menu also includes kosher dill pickles as well as brownies and "triple chunk" chocolate and oatmeal raisin cookies. In 2021, Jimmy John's began introducing limited-time offers to its menu. The company introduces two to three limited-time offers a year, starting with the "Smokin’ Kickin' Chicken" sandwich in February 2021. Their summer wraps, which started as a limited time offer, became a permanent installation in 2023. In March 2025, Jimmy John's introduced a new line of toasted sandwiches.
=== Presentation === The clinical manifestations of this disease are anaemia, jaundice, fever, hepatomegaly, splenomegaly, lymphadenopathy, haematochezia and persistent bleeding from the nose, oral cavity and the tips, margins and outer surface of the pinnae. Other features include lethargy, loss of appetite, weakness, weight loss, dyspnoea, petechiae and haematemesis.
Margaret Victoria Ware, Senior Executive Officer, Overseas Development Administration. Perween Warsi, Managing Director, S & A Foods Ltd. For services to the Food Manufacturing Industry. Robert William Waterson. For services to the community in Norwich, Norfolk. Professor Roy Watling, Head of Mycology, Royal Botanic Garden Edinburgh. For services to Science. Arthur Aiken Watson. For services to the community in Tarves, Aberdeenshire. Dennis Drysdale Watson, Driver, Badgerline Bus Company (Thamesway), Southend, Essex. For services to Public Transport. Simon Watts, Chief Scientist, Racal Radar Defence Systems Ltd. For scientific services to the Defence Industry. Geoffrey Wingyett Webber, . For services to the community on the Isle of Wight. Geoffrey Gilbert Wells. For services to the community in Wick, West Sussex. Ronald Edward Westacott. For services to the community in Seend, Wiltshire. Brenda Maria Wheatley, Support Manager 3, the Buying Agency, Cabinet Office (Office of Public Service). The Reverend Derek White. For services to Homeless People in London. Marguerite Elizabeth White. For services to the community in Liverpool. Derek Frederick Whitehouse. For services to the community in Melton Mowbray, Leicestershire. Brian Peter Whitford. For services to the Personnel Protective Equipment Industry. Ivan William Whittaker, Craftsman, National Grid Company plc. For services to Industrial Relations. Keith Anthony Wicks, Head of Information Technology and Communications, Port of London Authority. For services to the Port Authority. Harry Holmes St. John Wild.
Sources: en.wikipedia.org
A similar stele fragment (ES 1027), 57 centimeters high by 42 centimeters wide by 20 deep, depicting Naram-Sin was found a few miles north-east of Diarbekr, at Pir Hüseyin in a well, though this was not its original context. It is said to have been first found in Miyafarkin, a village about 75 kilometers northeast of Diarbekr. Fragments of an alabaster stele representing captives being led by Akkadian soldiers is sometimes attributed to Narim-Sin (or Rimush or Manishtushu) on stylistic grounds. In particular, it is considered as more sophisticated graphically than the steles of Sargon of Akkad or those of Rimush or Manishtushu. Two fragments (IM 55639 and IM 59205) are in the National Museum of Iraq, and one (MFA 66.89) is the Boston Museum. The stele is quite fragmentary, but attempts at reconstitution have been made. Depending on sources, the fragments were excavated in Wasit, al-Hay district, Wasit Governorate, or in Nasiriyah, both locations in Iraq. It is thought that the stele represents the result of the campaigns of Naram-Sin to Cilicia or Anatolia. This is suggested by the characteristics of the booty carried by the soldiers in the stele, especially the metal vessel carried by the main soldier, the design of which is unknown in Mesopotamia, but on the contrary well known in contemporary Anatolia.
Wool Bradford, Halifax and Huddersfield grew through the development of woollen mills. Leeds' traditional industry was the manufacturing of cloth while heavier engineering industries facilitated growth in South Leeds. The Heavy Woollen District covered towns such as Dewsbury, Batley, Morley, Ossett, Cleckheaton and Heckmondwike. The woollen and cloth industries declined throughout the twentieth century.
Vitamin A is a fat-soluble vitamin that is an essential nutrient. The term "vitamin A" encompasses a group of chemically related organic compounds that includes retinol, retinyl esters, and several provitamin (precursor) carotenoids, most notably β-carotene (beta-carotene). Vitamin A has multiple functions: growth during embryo development, maintaining the immune system, and healthy vision. For aiding vision specifically, it combines with the protein opsin to form rhodopsin, the light-absorbing molecule necessary for both low-light (scotopic vision) and color vision. Vitamin A occurs as two principal forms in foods: 1) retinoids, found in animal-sourced foods, either as retinol or bound to a fatty acid to become a retinyl ester, and 2) the carotenoids α-carotene (alpha-carotene), β-carotene, γ-carotene (gamma-carotene), and the xanthophyll beta-cryptoxanthin (all of which contain β-ionone rings) that function as provitamin A in herbivore and omnivore animals which possess the enzymes that cleave and convert provitamin carotenoids to retinol. Some carnivore species lack this enzyme. The other carotenoids do not have retinoid activity. Dietary retinol is absorbed from the digestive tract via passive diffusion. Unlike retinol, β-carotene is taken up by enterocytes by the membrane transporter protein scavenger receptor B1 (SCARB1), which is upregulated in times of vitamin A deficiency (VAD). Retinol is stored in lipid droplets in the liver.
The outbreak of the French Revolution had been received with great alarm by the rulers of Europe's continental powers, further exacerbated by the execution of Louis XVI, and the overthrow of the French monarchy. In 1793, Austria, the Kingdom of Sardinia, the Kingdom of Naples, Prussia, the Kingdom of Spain, and the Kingdom of Great Britain formed the First Coalition to curtail the growing power of revolutionary France. Measures such as mass conscription, military reforms, and total war allowed France to defeat the coalition, despite the concurrent civil war in France. Napoleon, then a general of the French Revolutionary Army, forced the Austrians to sign the Treaty of Campo Formio, leaving only Great Britain opposed to the fledgling French Republic. A Second Coalition was formed in 1798 by Great Britain, Austria, Naples, the Ottoman Empire, the Papal States, Portugal, Russia, and Sweden. The French Republic, under the Directory, suffered from heavy levels of corruption and internal strife. The new republic also lacked funds, no longer enjoying the services of Lazare Carnot, the minister of war who had guided France to its victories during the early stages of the Revolution. Napoleon Bonaparte, commander of the Armée d'Italie in the latter stages of the First Coalition, had launched a campaign in Egypt, intending to disrupt the British control of India. Pressed from all sides, the Republic suffered a string of successive defeats against revitalised enemies, who were supported by Britain's financial help.
== Cellular cardiomyoplasty == Cellular cardiomyoplasty is a method which augments myocardial function and cardiac output by directly growing new muscle cells in the damaged myocardium (heart muscle). Tissue engineering, which is now being categorized as a form of regenerative medicine, can be defined as biomedical engineering to reconstruct, repair, and improve biological tissues. Research efforts in tissue engineering have been ongoing and it is emerging as one of the key areas of medical research. Furthermore, there are vast developments in tissue engineering, which involve leveraging of technologies from biomaterials, molecular medicine, biochemistry, nanotechnology, genetic and biomedical engineering for regeneration and cell expansion targets to restructure and/or repair human organs. Injection of cardiomyogenic and/or angiogenic stem cells have been proposed as alternatives to existing treatments. For cardiovascular application, skeletal myoblasts are of great interest as they can be easily isolated and are associated with high proliferation rate. These cells have also been demonstrated to be hypoxia-resistant. Bone marrow contains different cell populations, which exhibit excellent plasticity toward cardiogenic and endothelial cells. These cell populations are endothelial progenitor cells, hematopoietic stem cells and mesenchymal stem cells. Adipose tissue host progenitor cells with reported interesting cardiomyogenic and vasculogenic potential in the sense that they improve heart functions and reduce infarction size in rodent animal models.
Sources: en.wikipedia.org
Bupropion/trazodone (developmental code names S1P-104 and S1P-205; proposed brand names Lorexys and Orexa) is a combination of the norepinephrine–dopamine reuptake inhibitor (NDRI) bupropion and the serotonin antagonist and reuptake inhibitor (SARI) trazodone which is under development for the treatment of erectile dysfunction, female sexual dysfunction, and male sexual dysfunction. It is taken orally. Both bupropion and trazodone have individually been found to be effective and used for treating sexual dysfunction, such as low sexual desire or erectile dysfunction. Bupropion/trazodone is under development by S1 Pharmaceuticals or S1 Biopharma. As of September 2021, it is in phase 2 clinical trials for erectile dysfunction and female sexual dysfunction, whereas no recent development has been reported for male sexual dysfunction.
The first five stations, covering the approaches to London, were installed by 1937 and began full-time operation in 1938. Over the next two years, additional stations were built while the problem of disseminating the information to the fighter aircraft led to the first integrated ground-controlled interception network, the Dowding system. By the time the war started, most of the east and south coasts had radar coverage. Chain Home proved important during the Battle of Britain in 1940. CH systems could detect enemy aircraft while they were forming over France, giving RAF commanders ample time to marshal their aircraft in the path of the raid. This had the effect of multiplying the effectiveness of the RAF to the point that it was as if they had three times as many fighters, allowing them to defeat frequently larger German forces. The Chain Home network was continually expanded, with over 40 stations operational by the war's end, including mobile versions for use overseas. Late in the war, when the threat of Luftwaffe bombing had ended, the CH systems were used to detect V2 missile launches. UK radar systems were wound down after the war but the start of the Cold War led to the Chain Home radars being pressed into service in the new ROTOR system until replaced by newer systems in the 1950s. Only a few of the original sites remain.
=== Sources === Fulbrook, Mary (1991). A Concise History of Germany. Cambridge University Press. ISBN 978-0-521-36836-0. Murdoch, Adrian (2004). "Germania Romana". In Murdoch, Brian; Read, Malcolm (eds.). Early Germanic Literature and Culture. Boydell & Brewer. pp. 55–73. ISBN 1-57113-199-X.
Wide nose – To narrow a too-wide nose, the plastic surgeon cuts, contours, and rearranges the craniofacial bones to achieve the desired functional and aesthetic outcome of a narrower, straighter nose. To leave no visible, surgical scars upon the new nose, the surgeon effects the osteotome (bone chisel) incisions to the nasal bones beneath the facial skin. Illustration 1: The surgeon cuts the excessively wide bones of the upper nasal dorsum (violet) with an osteotome (bone chisel), then detaches, corrects, and relocates them inwards, to a position, between the ocular orbits (red), that narrows the width of the nasal dorsum. Illustration 2: The surgeon chisels two cuts (incisions) to the nasal bones, each incision begins at the nasal cavity. The first incision begins at the yellow dot and extends upwards, along the green arrow, until meeting the zig-zag line (red). The second incision begins at the blue dot and extends upwards, along the black arrow, until meeting the zig-zag line (red). Once cut and loosened from the face, the nasal bone pieces are corrected, then pushed inwards and re-set, thus narrowing the nose.
Sources: en.wikipedia.org
肽键在 214 nm 附近有较强吸收，适合检测缺少芳香侧链的短肽。该波长的基线受流动相组成与梯度影响较大。因此流动相与梯度条件需要固定并完整记录。
仅凭保留时间不足以定性，通常需要质谱给出与理论值一致的分子量。进一步可用碎裂谱与参考谱比对。保留时间、分子量与碎裂谱三者吻合时，身份判断较为可靠。
这取决于缓冲液、pH、温度与微生物负荷，并不存在通用时限。常见做法是分装冷冻并尽量缩短室温放置时间。出现浑浊或沉淀时应弃用并重新配制。
碱性 pH、较高温度、强光照射与反复冻融都会加快水解、氧化或脱酰胺。溶液中的金属离子也可能催化氧化。控制这些变量比单纯降低浓度更有效。