The short version of circular dichroism fits in a sentence. The long version — which is the one that helps — is below.
Reviewed 2025-09-20. Anything still debated is marked as such rather than presented as settled.
Both receptors are class B G protein-coupled receptors that signal largely through Gs-mediated cyclic AMP production. Activation within pancreatic islets increases glucose-dependent insulin secretion and suppresses glucagon release when glucose is elevated. Outside the pancreas, signaling in the central nervous system and gut appears to influence appetite and gastric emptying. The relative contribution of each receptor to observed clinical effects remains under investigation, and the two pathways are not simply additive in practice.
Reported outcomes in large trials include dose-dependent weight reduction and improvements in glycemic markers over periods ranging from several months to more than a year. Whether the compound alters long-term cardiovascular or renal outcomes is being examined in dedicated outcome studies, so those questions remain open. Labeling describes gastrointestinal effects such as nausea and diarrhea, which tend to appear during dose escalation. Discontinuation rates and the durability of effects after treatment stops vary across study populations and are still debated.
该化合物的名称与结构由国际非专利名称体系统一维持，不同文献中出现的同义写法主要在拼写顺序或盐形式描述上不同。研究者通常通过受体结合实验、细胞内环磷酸腺苷积累测定以及动物模型来确认其双激动活性。相当一部分分子层面的细节——例如两条受体通路之间的信号交叉作用——尚处于开放问题状态。
当前公开资料把 tirzepatide 归为肠促胰素类受体双重激动剂。它并非激素天然变体，而是经过序列改造的工程化肽。其分子量、等电点与疏水性等基础参数已在药典和化学数据库中收录，可作为分析检测和质量研究的参照。
Tirzepatide 是一种由 39 个氨基酸组成的合成肽，分子结构上以 GIP 序列为骨架并引入脂肪酸侧链修饰，使其能够同时与葡萄糖依赖性促胰岛素多肽（GIP）受体和胰高血糖素样肽-1（GLP-1）受体结合。这种双重激动特性使它在同类肽类药物中区别于选择性 GLP-1 受体激动剂。该分子最早由一家制药公司在 2010 年代报道，随后进入糖尿病与体重管理领域的临床研究。
| Property | Value | Notes |
|---|---|---|
| Molecular class | Synthetic 39-residue peptide | GIP-derived backbone with non-natural residues |
| Molar mass | Approximately 4.8 kDa | Peptide chain plus linker and lipid modifications |
| Appearance | White to off-white powder | Typical of lyophilized research material |
| Solubility | Soluble in water and aqueous buffer | Practically insoluble in nonpolar solvents |
| Storage temperature | Typically −20 °C for dry powder | Solutions usually held at 2–8 °C short term |
Identity and purity are usually established with reversed-phase high-performance liquid chromatography for the main peak and with mass spectrometry for the observed molecular mass. Peptide mapping after enzymatic digestion confirms the primary sequence, while amino acid analysis provides a quantitative composition check. Size-exclusion chromatography and ion-exchange chromatography are used to look for aggregates and charge variants. Water content, residual solvents, and counter-ion content are measured separately, since a lyophilised powder is often reported on an as-is basis unless a correction is applied.
Research-grade material circulates through suppliers that differ widely in documentation and testing practice, so a certificate of analysis is a starting point rather than proof of quality. Independent verification typically repeats chromatographic purity and mass confirmation on the received lot, and compares results against a retained reference standard. Regulatory status varies by jurisdiction, and a substance cleared as a medicine is not interchangeable with a research chemical of the same name. Open questions include how closely non-pharmaceutical lots match approved material in impurity profile and in aggregate content.
Routine characterization of the peptide relies on reversed-phase high-performance liquid chromatography for purity assessment, usually with ultraviolet detection near 214 nanometers. Intact mass measurement by liquid chromatography coupled to mass spectrometry confirms molecular identity against a theoretical value. Sequence-level confirmation uses enzymatic digestion followed by tandem mass spectrometry, an approach known as peptide mapping. Amino acid analysis gives an independent check on composition. Circular dichroism spectra are used to estimate helical content in aqueous buffer.
Stability depends strongly on physical form. The dry powder is generally regarded as stable for extended periods when held at or below minus twenty degrees Celsius in a sealed, desiccated container. In solution, degradation pathways include deamidation of asparagine and glutamine residues, oxidation of methionine, and aggregation. Reaction rates for these pathways rise with temperature. Repeated freezing and thawing of solutions promotes aggregation, and light exposure can accelerate some oxidative changes. Buffer composition and pH influence which pathway dominates at a given temperature.
Consequently, the players were handed the full minimum suspensions of two years – these were backdated to 31 March 2015, which was the date of the original AFL Tribunal not guilty verdict; and, with credit taken for the periods of provisional suspension already served during the 2014/15 offseason, resulted in most of the suspensions running until November 2016.
=== United States herbalism fraud === Over the years 2017–2021, the US Food and Drug Administration (FDA) issued warning letters to numerous herbalism companies for illegally marketing products under "conditions that cause them to be drugs under section 201(g)(1) of the Act [21 U.S.C. § 321(g)(1)], because they are intended for use in the diagnosis, cure, mitigation, treatment, or prevention of disease and/or intended to affect the structure or any function of the body" when no such evidence existed. During the COVID-19 pandemic, the FDA and US Federal Trade Commission issued warnings to several hundred American companies for promoting false claims that herbal products could prevent or treat COVID-19 disease.
=== Princess Elizabeth and Philip Mountbatten's wedding cake === Princess Elizabeth and Philip Mountbatten were offered many cakes from well-wishers around the world for their wedding on 20 November 1947. Of these they accepted only 12, including one from J. Lyons and Co. They created a three-tiered cake, mounted on a silver stand, made by F E Jacobs, chief decorator of J Lyons' Ornamental Department. It stood 1.8 metres high and weighed 63 kg. The first and second tiers featured specially commissioned 10 cm blue and white Wedgwood Jasper vases set in alcoves behind silver pillars, with smaller vases on the third tier. The cake's panels depicted Princess Elizabeth's coat of arms, the couple's initials and a Naval crown. Atop the third tier sat a larger Jasper vase, filled with fresh flowers and trailing orange blossom.
family operates as a social unit, with social and business functions merged; leadership positions down to middle management are kinship based; the higher the position, the closer the kinship relationship; group assigns leadership positions to a central group of family members, including fictive god-parental relationship reinforcement; the leadership group are assigned to legal or illegal enterprises, but not both; and, transfer of money, from legal and illegal business, and back to illegal business is by individuals, not companies. Strong family ties are derived from the traditions of southern Italy, where family rather than the church or state is the basis of social order and morality.
The authors conclude that past respiratory disorders maximally contribute to IPF risk, followed by known IPF comorbidities, metabolic diseases, cardiovascular abnormalities, and diseases of the eye, with the overall pattern of the importance ranking substantially invariant across the sexes.
Sources: en.wikipedia.org
Malcolm H. Kerr first coined the term "Arab Cold War" to refer to a political conflict inside the Arab world between Nasserist republics defending Arab socialism, Pan-Arabism, and Arab nationalism led by Nasser's Egypt, against traditionalist monarchies led by Saudi Arabia. An Atlantic Council member Bilal Y. Saab, an About.com writer Primoz Manfreda, an Iranian scholar Seyyed Hossein Mousavian and a Princeton University scholar Sina Toossi, journalist Kim Ghattas, Foreign Policy journalist Yochi Dreazen, Brookings Institution researcher Sultan Barakat, and Newsweek journalist Jonathan Broder use the term "cold war" to refer to tensions between Saudi Arabia and Iran. In February 2016, a University of Isfahan professor Ali Omidi dismissed the assumptions that the conflict between Iran and Saudi Arabia would grow tense.
Museums from across the United States significantly expanded their programs aimed at children, including K-12 students, during the 2000s and 2010s, according to the American Alliance of Museums and the Institute of Museum and Library Services.
=== Transcription factors in differentiation === Downstream signaling of the transcription factor aryl hydrocarbon receptor (AHR) is essential for Th22 production of interleukin-22 (IL-22). RORγt acts as a positive transcription factor and T-bet acts as a negative transcription factor for Th22 cell differentiation. However, additional intracellular molecules involved in Th22 differentiation are still being investigated.
Refugees typically rely on limited sources of vitamin B3 provided to them, often peanuts (which, in Africa, may be supplied in place of local groundnut staples, such as the Bambara or Hausa groundnut); the instability in the nutritional content and distribution of food aid can be the cause of pellagra in displaced populations. In the 2000s, outbreaks occurred in countries such as Angola, Zimbabwe, and Nepal. In Angola specifically, recent reports show a similar incidence of pellagra since 2002, with clinical pellagra in 0.3% of women and 0.2% of children, and niacin deficiency in 29.4% of women and 6% of children related to high untreated corn consumption. In other countries such as the Netherlands and Denmark, even with sufficient intake of niacin, cases have been reported. In this case, deficiency might happen not just because of poverty or malnutrition, but secondary to alcoholism, drug interaction (psychotropic, cytostatic, tuberculostatic, or analgesics), HIV, vitamin B2 and B6 deficiency, or malabsorption syndromes such as Hartnup disease and carcinoid tumors.
Sources: en.wikipedia.org
It acts as an agonist at both the GIP and GLP-1 receptors, two related class B G protein-coupled receptors. This dual activity distinguishes it from single-receptor GLP-1 agonists. The clinical consequences of engaging both receptors are still being characterized.
It is given by subcutaneous injection, generally on a weekly schedule. Dosing usually begins low and increases in steps to limit gastrointestinal side effects. Formulated product is supplied as a ready-to-use pen or vial in most markets.
No. Receptor engagement is documented, but how central appetite circuits, gut signals, and insulinotropic effects combine is incompletely resolved. Investigators continue to separate GIP-driven from GLP-1-driven contributions in animal and human models.
它属于合成修饰肽，同时激动 GIP 与 GLP-1 两种肠促胰素受体。这类分子通常被称为双重肠促胰素受体激动剂，与选择性 GLP-1 激动剂在靶点范围上不同。