A practical reference on body composition: what it is, how it behaves, what the literature reports, and where the honest uncertainties sit.
Reviewed 2026-05-30. Anything still debated is marked as such rather than presented as settled.
稳定性研究一般关注脱酰胺、氧化与聚集三类降解路径。脱酰胺多发生在天冬酰胺残基上，氧化常涉及甲硫氨酸与色氨酸，聚集则与浓度、温度以及容器界面接触有关。强制降解实验用于识别分子中较敏感的位点。这些结果会直接影响储存条件的设定与有效期的判断。
冻干粉通常在低温环境下保存，复溶之后需要按指定条件在较短时间内使用。反复冻融和剧烈振荡可能促进聚集，低吸附容器则能减少多肽在管壁上的损失。批号、日期与处理条件的完整记录，是后续复核与问题追溯的基础。
Body composition is assessed with dual-energy X-ray absorptiometry or comparable methods, which separate fat mass from lean mass. Reported losses include both compartments, and the ratio between them is a subject of ongoing analysis rather than a settled result. Waist circumference, blood pressure, and lipid panels are collected as supporting measures. Resting energy expenditure and substrate oxidation are measured in smaller mechanistic studies, where glucagon receptor activity is expected to matter. These substudies are typically short and small, so their findings carry wide uncertainty.
Interpretation depends on study phase and duration. Phase 2 programs are powered for weight and safety signals, not for cardiovascular or renal outcomes, which require event-driven designs. Gastrointestinal events such as nausea, diarrhea, vomiting, and constipation are the most frequently reported adverse effects and tend to cluster around dose escalation. Small increases in heart rate have been described. Because follow-up after treatment discontinuation is limited, questions about weight regain and durability are open rather than answered.
| Property | Value | Notes |
|---|---|---|
| 长期储存温度 | 约 -20°C 或更低 | 冻干粉常见保存条件 |
| 复溶溶剂 | 注射用水或指定缓冲液 | 按方案或说明书执行 |
| 容器材质 | 低吸附聚丙烯 | 减少多肽在管壁的吸附损失 |
| 主要降解路径 | 脱酰胺、氧化、聚集 | 由序列与工艺条件共同决定 |
| 追溯材料 | 分析证书与批次记录 | 用于来源与纯度核实 |
Clinical development has advanced through phase 2 trials in adults with obesity and type 2 diabetes. Reported phase 2 results described substantial average weight reduction over roughly forty-eight weeks of weekly dosing. A phase 3 program is ongoing to confirm efficacy and assess long-term safety. Because the compound has not received regulatory approval, it is not available as a prescription product. Public discussion of retatrutide often conflates trial findings with marketed status, an important distinction when interpreting coverage of the topic.
Retatrutide is a synthetic peptide developed as a single molecule that activates three distinct hormone receptors: GLP-1, GIP, and glucagon. The compound carries the internal designation LY3437943 and was engineered by modifying the backbone of glucose-dependent insulinotropic polypeptide. Its sequence incorporates non-natural amino acids and a fatty acid side chain that extends circulation time. The triple-agonist design aims to combine appetite suppression, improved insulin response, and increased energy expenditure in one agent. Published reports describe it as an investigational product rather than an approved medicine.
Each receptor contributes a different physiological effect. Activation of the GLP-1 receptor slows gastric emptying and reduces appetite signaling in the brain. GIP receptor activity influences insulin secretion and lipid handling, while glucagon receptor stimulation raises energy use and fat oxidation. Combining these pathways is intended to produce weight loss beyond what single- or dual-receptor agonists achieve. Researchers attribute the observed potency to simultaneous engagement of all three targets, though the exact contribution of each receptor to overall effect remains under investigation.
Stability depends strongly on physical state. Dry powder is comparatively robust when held at -20 °C or below, desiccated and shielded from light; under those conditions degradation is slow and measured over years. Once dissolved, the peptide becomes far more vulnerable: backbone hydrolysis, oxidation of susceptible residues and aggregation all proceed faster in solution, and the rates climb with temperature and with pH far from neutral. Refrigerated storage at 2–8 °C extends usable life for short periods, and repeated freeze–thaw cycles are best avoided.
Identity and purity are established by instrumental methods rather than by appearance. Reversed-phase high-performance liquid chromatography separates the peptide from related impurities and yields a purity value, usually expressed as the share of total peak area. Mass spectrometry checks that the observed mass agrees with the mass calculated from the published sequence, while peptide mapping or amino acid analysis adds structural evidence. Water content, counter-ion identity and residual solvents are sometimes reported as well. A certificate of analysis should name the method behind each figure, because results are method-dependent.
ATAC-seq (Assay for Transposase-Accessible Chromatin using sequencing) is a laboratory technique used in molecular biology to assess genome-wide chromatin accessibility. The technique was introduced in 2013 by the labs of Will Greenleaf and Howard Chang at Stanford University as an alternative to MNase-seq, FAIRE-Seq and DNase-Seq with faster turnaround time, simpler protocol, and lower DNA input requirements.
== References == This article was submitted to WikiJournal of Science for external academic peer review in 2017 (reviewer reports). The updated content was reintegrated into the Wikipedia page under a CC-BY-SA-3.0 license (2018). The version of record as reviewed is: Mike Christie; et al. (2018). "Radiocarbon dating" (PDF). WikiJournal of Science. 1 (1): 6. doi:10.15347/wjs/2018.006. Wikidata Q55120317.
When Eng arrived at Amylin's San Diego headquarters, he was astonished to discover how much information Amylin's scientists had already figured out about exendin-4 in the brief period of time after Young saw his poster, which convinced him that Amylin was the right company to partner with. Amylin went on to create exenatide, a synthetic version of exendin-4, and later formed an alliance with Lilly in 2002 to bring the drug to market. Exenatide was predicted by Amylin scientist Alain Baron to begin undergoing the Food and Drug Administration's approval process in 2004. Exenatide was approved by the FDA in April 2005, for people whose diabetes is not well controlled on other oral medications. This was a landmark event which proved that targeting the GLP-1 receptor was a viable strategy and inspired other pharmaceutical companies to focus their research and development on that receptor. In 2011, Lilly and Amylin dissolved their partnership, with Amylin keeping the rights to exenatide. Meanwhile, Lilly had been awakened to the possibilities of this class of drugs and continued to develop newer drugs of the same class. By October 2024, the blockbuster drug tirzepatide had transformed Lilly into the most valuable drug company in the world.
== Bodily location == In mammals, gluconeogenesis has been believed to be restricted to the liver, the kidney, the intestine, and muscle, but recent evidence indicates gluconeogenesis occurring in astrocytes of the brain. These organs use somewhat different gluconeogenic precursors. The liver preferentially uses lactate, glycerol, and glucogenic amino acids (especially alanine) while the kidney preferentially uses lactate, glutamine and glycerol. Lactate from the Cori cycle is quantitatively the largest source of substrate for gluconeogenesis, especially for the kidney. The liver uses both glycogenolysis and gluconeogenesis to produce glucose, whereas the kidney only uses gluconeogenesis. After a meal, the liver shifts to glycogen synthesis, whereas the kidney increases gluconeogenesis. The intestine uses mostly glutamine and glycerol. Propionate is the principal substrate for gluconeogenesis in the ruminant liver, and the ruminant liver may make increased use of gluconeogenic amino acids (e.g., alanine) when glucose demand is increased. The capacity of liver cells to use lactate for gluconeogenesis declines from the preruminant stage to the ruminant stage in calves and lambs. In sheep kidney tissue, very high rates of gluconeogenesis from propionate have been observed. In all species, the formation of oxaloacetate from pyruvate and TCA cycle intermediates is restricted to the mitochondrion, and the enzymes that convert phosphoenolpyruvic acid (PEP) to glucose-6-phosphate are found in the cytosol.
Sources: en.wikipedia.org
== Purification of plasmid DNA == It is important to consider the downstream applications of the plasmid DNA when choosing a purification method. For example, if the plasmid is to be used for transfection or electroporation, a purification method that results in high purity and low endotoxin levels is desirable. Similarly, if the plasmid is to be used for sequencing or PCR, a purification method that results in high yield and minimal contaminants is desirable. However, multiple methods of nucleic acid purification exist. All work on the principle of generating conditions where either only the nucleic acid precipitates, or only other biomolecules precipitate, allowing the nucleic acid to be separated.
=== Cancer === Over-activation of mTOR signaling significantly contributes to the initiation and development of tumors and mTOR activity was found to be deregulated in many types of cancer including breast, prostate, lung, melanoma, bladder, brain, and renal carcinomas. Reasons for constitutive activation are several. Among the most common are mutations in tumor suppressor PTEN gene. PTEN phosphatase negatively affects mTOR signalling through interfering with the effect of PI3K, an upstream effector of mTOR. Additionally, mTOR activity is deregulated in many cancers as a result of increased activity of PI3K or Akt. Similarly, overexpression of downstream mTOR effectors 4E-BP1, S6K1, S6K2 and eIF4E leads to poor cancer prognosis. Also, mutations in TSC proteins that inhibit the activity of mTOR may lead to a condition named tuberous sclerosis complex, which exhibits as benign lesions and increases the risk of renal cell carcinoma. Increasing mTOR activity was shown to drive cell cycle progression and increase cell proliferation mainly due to its effect on protein synthesis. Moreover, active mTOR supports tumor growth also indirectly by inhibiting autophagy. Constitutively activated mTOR functions in supplying carcinoma cells with oxygen and nutrients by increasing the translation of HIF1A and supporting angiogenesis. mTOR also aids in another metabolic adaptation of cancerous cells to support their increased growth rate—activation of glycolytic metabolism.
=== Uniform === Until 1914 the distinguishing colour of the Don Cossack Host was red, worn on the cap bands and wide trouser stripes of a dark blue uniform of the loose-fitting cut common to the Steppe Cossacks. Tall lambskin hats were worn on occasion, with red cloth tops edged in white lace. Silver metal scrolls were worn on the headdress to denote the distinguished conduct of individual regiments. Officers had silver braiding on their collars and epaulettes, plus silver/black girdles. Shoulder-straps of other ranks were the same dark blue as the caftan (coat). A whip was used instead of spurs. Prior to 1908, individual cossacks from all Hosts were required to provide their own uniforms, together with horses and harness. The size and relative affluence of the Don Cossack Host permitted the setting up of communally owned clothing factories. In 1908, a khaki field tunic was adopted, replacing the dark blue coats or white summer blouses previously worn for ordinary duties. The blue riding breeches with broad red stripes long characteristic of the Don Host, continued to be worn even on active service during both World Wars. The Don Cossack Battery of the Imperial Guard wore a "Tsar's green" uniform, a dark shade common to the army, with the black and red distinctions of the artillery as a branch.
It is then lowered by a strong rope over an outcrop of coral and the boat trawls over the coral causing it to break off and be caught in the netting. The device is then drawn to the surface by the boat crew.
== Biography == David Colin Sherrington was born at Webster Street, Litherland, Liverpool on 5 March 1945, the second child of Alfred George Sherrington, a dock labourer, and Lucy Gladys Sherrington, née Pyke. He attended two primary/junior schools before passing the eleven-plus exam, enabling him to go to Waterloo Grammar School. Crosby. His A-Level results were good enough for him to by-pass the first year of the chemistry degree course at the University of Liverpool and enter the second year in 1963. He graduated first-class in 1966. Sherrington stayed at Liverpool for his PhD, under Anthony Ledwith, and then continued as a research assistant in the same department so that he could help his recently widowed mother. In 1971 he applied for two fellowships: at Heriot-Watt University and at the University of Strathclyde. He was successful with the second, and took up a post in Alastair M. North’s department of pure and applied chemistry. Before moving north, David Sherrington married Valerie Vinnicombe at County Road Methodist Church, Walton in June 1972. They had met at the university tennis club, where she was secretary and he was trying to lose weight. By 1975 his researches in Scotland had become focused on polymer-supported reactions. In 1984 Sherrington accepted a three-year contract at Unilever’s Port Sunlight laboratory under its research director Sir Geoffrey Allen, FRS. His job was to build and lead the Polymer Science Area. He worked in fields that had practical value – always his wish – such as biodegradable polymers and molecular imprinting.
Sources: en.wikipedia.org
For example, a reactivity ratio that is less than one for component 1 indicates that this component reacts with the other type of monomer more readily. Given this information, which is available for a multitude of monomer combinations in the "Wiley Database of Polymer Properties", the Mayo-Lewis equation can be used to predict the composition of the polymer product for all initial mole fractions of monomer. This equation is derived using the Markov model, which only considers the last segment added as affecting the kinetics of the next addition; the Penultimate Model considers the second-to-last segment as well, but is more complicated than is required for most systems. When both reactivity ratios are less than one, there is an azeotropic point in the Mayo-Lewis plot. At this point, the mole fraction of monomer equals the composition of the component in the polymer. There are several ways to synthesize random copolymers. The most common synthesis method is free radical polymerization; this is especially useful when the desired properties rely on the composition of the copolymer rather than the molecular weight, since free radical polymerization produces relatively disperse polymer chains. Free radical polymerization is less expensive than other methods, and produces high-molecular weight polymer quickly. Several methods offer better control over dispersity. Anionic polymerization can be used to create random copolymers, but with several caveats: if carbanions of the two components do not have the same stability, only one of the species will add to the other.
Kidder had mental health issues from a young age, which stemmed from undiagnosed bipolar disorder. "I knew I was different, had these mind flights that other people didn't seem to have," she recalled. At age 14, she attempted suicide. Kidder found an outlet in acting, as she felt she could "let my real self out ... and no one would know it was me." "Nobody ever encouraged me to be an actress," she recalled. "It was taken as a joke... As a teenager, I envisioned myself in every book I read. I wanted to be Henry Miller and Thomas Wolfe. I wanted to eat everything on the world's platter, but my eyes were bigger than my stomach." She attended several schools during her youth as a result of her family's relocations, eventually graduating from Havergal College, a high-school-level boarding school in Toronto, in 1966. In 1966, she found herself pregnant by her boyfriend, who arranged for an illegal abortion. The abortionist was located in a hotel room and filled Kidder's uterus with Lysol to terminate the pregnancy. After graduating from Havergal, Kidder relocated to Vancouver to attend the University of British Columbia, but dropped out after one year. She returned to Toronto, where she found work as a model.
==== Film works and graphic novel ==== Antonov worked on the 2006 film Renaissance directed by Christian Volkman. He then wrote and illustrated the graphic novel The Colony: A Structure Celebrating the Triumphs of Technology, published in 2010. Antonov was also a co-writer and production designer of the 2011 French sci-fi film The Prodigies.
Sauvagine is a neuropeptide from the corticotropin-releasing factor (CRF) family of peptides and is orthologous to the mammalian hormone, urocortin 1, and the teleost fish hormone, urotensin 1. It is 40 amino acids in length, and has the sequence XGPPISIDLSLELLRKMIEIEKQEKEKQQAANNRLLLDTI-NH2, with a pyrrolidone carboxylic acid modification at the N-terminal and amidation of the C-terminal isoleucine residue. It was originally isolated from the skin of the frog Phyllomedusa sauvagii. Given its relation to other CRF-related peptides, it exerts similar physiological effects as corticotropin-releasing hormone. Sauvagine belongs to the corticotropin-releasing factor (CRF) family that also includes CRF, urocortin l/urotensin l, urocortin II and urocortin III.
Sources: en.wikipedia.org
常用质谱测定分子量，再结合肽图或序列分析验证一级结构。单一检测手段一般难以排除结构相近的类似物。多种方法相互印证更为可靠。
低温可以降低水解与聚集的速率，从而延缓降解进程。温度反复波动本身也可能造成相变与样品损失。稳定的储存条件是可重复结果的前提。
分析证书、批次编号、所用检测方法与结果，以及标称储存条件。缺少方法细节的报告难以独立复核。记录完整性决定了追溯能否成立。
A responder analysis counts participants who cross a threshold, such as five or ten percent weight loss. It complements average percent change by showing how widely results are distributed. The two measures can diverge when a subset of participants loses a large amount.