A practical reference on 冻干粉: what it is, how it behaves, what the literature reports, and where the honest uncertainties sit.
Reviewed 2026-06-12. Anything still debated is marked as such rather than presented as settled.
Tirzepatide is a synthetic peptide built from 39 amino acid residues. Its backbone derives from the native glucose-dependent insulinotropic polypeptide sequence, altered at several positions to resist enzymatic cleavage. A fatty diacid group attached through a linker extends plasma residence time by promoting reversible binding to serum albumin. The molecule carries a net negative charge near physiological pH and has a reported molecular weight close to 4813 daltons. These features separate it from shorter incretin analogs and account for its prolonged dosing interval.
Pharmacologically, tirzepatide activates two distinct G protein-coupled receptors: the glucose-dependent insulinotropic polypeptide receptor and the glucagon-like peptide-1 receptor. Binding at each target triggers cyclic AMP accumulation and downstream signaling in pancreatic beta cells, adipose tissue and the central nervous system. Because the two pathways overlap only partially, the combined effect on insulin secretion, glucagon suppression and appetite signaling differs from that of selective single-receptor compounds. Affinity is not equal across the two targets, and the clinical meaning of that imbalance remains an area of active study.
Clinical research programs have evaluated tirzepatide in adults with type 2 diabetes and in adults with obesity or excess weight. Trials generally reported reductions in glycated hemoglobin and body weight across treatment periods of several months. Since these studies enrolled defined populations under controlled conditions, the findings describe group averages rather than individual outcomes. Open questions include the durability of effects after treatment stops, variation among subgroups, and the long-term consequences of sustained dual receptor stimulation. Published trial summaries should be consulted for exact measurements rather than secondary accounts.
定量分析的主流方法是反相高效液相色谱联用紫外或质谱检测，利用肽在疏水固定相上的保留行为确定纯度与含量。对于生物基质中的浓度测定，常采用液相色谱串联质谱，并配合固相萃取或蛋白沉淀进行样品前处理。免疫分析法也可使用，但可能受到结构相关肽的交叉反应干扰。
纯度评估通常综合反相色谱、体积排阻色谱与质谱三方面信息：前者反映疏水性杂质，后者反映聚集体，质谱则确认分子量与主要降解产物。有关降解途径的完整图谱——例如脱酰胺、氧化与水解各占多大比例——在不同储存条件下仍有差异，属于需要逐案验证的问题。
| Property | Value | Notes |
|---|---|---|
| Molecular formula | C225H348N48O68 | Includes the 39-residue backbone and the attached fatty diacid |
| Molecular weight | Approximately 4813 Da | Average mass; the monoisotopic value is slightly lower |
| Receptor targets | GIP receptor and GLP-1 receptor | Dual engagement defines the pharmacological class |
| Backbone length | 39 amino acids | Sequence modified from native glucose-dependent insulinotropic polypeptide |
| Albumin interaction | Reversible, mediated by the fatty diacid | Slows renal clearance and lengthens circulation time |
An extended fatty diacid moiety promotes binding to serum albumin, which slows renal clearance and extends the circulating half-life to roughly five days. That property supports once-weekly administration and largely explains the dosing interval described in clinical reports. Published data come mainly from large randomised programmes that evaluated glycaemic control and body weight over periods of many months. Long-term outcomes beyond those trial windows, including what happens after treatment stops, remain an active area of investigation.
Tirzepatide is a synthetic peptide built from thirty-nine amino acids. Its sequence is derived from native glucose-dependent insulinotropic polypeptide, or GIP, with several non-natural residues and a fatty diacid side chain attached through a linker. The molecule behaves as a dual agonist at two incretin receptors, GIP and GLP-1, instead of targeting a single receptor. This dual engagement separates it from earlier single-receptor incretin compounds and underpins most of its reported pharmacological activity.
At the receptor level, the compound binds both GIP and GLP-1 receptors and triggers downstream signalling that raises cyclic AMP in target cells. GLP-1 receptor activation is associated with glucose-dependent insulin release, slower gastric emptying, and reduced appetite signalling. GIP receptor activation contributes effects that are less completely characterised, and how much each receptor adds to the overall clinical response is still an open question. The two pathways appear to interact in a complementary rather than a purely additive way.
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.
Solid tirzepatide is handled as a lyophilised, hygroscopic peptide powder that should be kept desiccated, protected from light, and stored frozen, typically at or below minus twenty degrees Celsius for long-term retention. Material left at ambient temperature for extended periods can take up moisture, which promotes aggregation and deamidation. Commercial liquid presentations are kept refrigerated between two and eight degrees Celsius and are not frozen. Reconstituted laboratory solutions are generally held cold and used within a short window because hydrolysis and oxidation continue slowly in solution.
Common degradation routes include hydrolysis of labile amide bonds, deamidation of asparagine and glutamine residues, oxidation of methionine and tryptophan, and non-covalent aggregation. Aggregates can form during freeze-thaw cycling, at elevated pH, or when peptide concentration is high. Each route produces characteristic chromatographic or mass shifts that are tracked during stability studies. Whether a given minor impurity alters biological activity is often an open question, and specification limits are typically set on identity and purity rather than on functional data for trace species.
Lyophilized material is generally held at -20 degrees Celsius or lower, desiccated and protected from light, where it remains stable for extended periods. Reconstituted or ready-to-use solution is usually kept at 2 to 8 degrees Celsius with minimal agitation. Repeated freeze-thaw cycles should be avoided because they promote aggregation and reduce the soluble monomer fraction. Shipment of frozen solid commonly uses dry ice, while refrigerated liquid moves with validated cold packs. Stability beyond documented periods is not established.
Characterization of the peptide relies on reversed-phase high-performance liquid chromatography for purity and related-substance profiling, with ultraviolet detection near 214 nanometers. Mass spectrometry confirms molecular mass and reveals modifications such as oxidation or deamidation. Peptide mapping after enzymatic digestion verifies the amino acid sequence, while amino acid analysis supplies compositional data. Circular dichroism and infrared spectroscopy are used to assess secondary structure, particularly the alpha-helical content that influences aggregation behavior in solution.
The French explorer and Acadia's first historian Marc Lescarbot described Jerusalem artichokes as being "as big as turnips or truffles," suitable for eating and taste "like chards, but more pleasant." In 1629, the English herbalist and botanist John Parkinson wrote that the widely grown Jerusalem artichoke had become very common and cheap in London, so much so "that even the most vulgar begin to despise them." In contrast, when they had first arrived in England, the tubers had been "dainties for the Queen." Lewis and Clark ate the tubers, prepared by an indigenous woman, in modern-day North Dakota. They have also been called the "Canadian truffle".
==== Neutrophil extracellular traps ==== In 2004, Brinkmann and colleagues described a striking observation that activation of neutrophils causes the release of web-like structures of DNA; this represents a third mechanism for killing bacteria. These neutrophil extracellular traps (NETs) comprise a web of fibers composed of chromatin and serine proteases that trap and kill extracellular microbes; thus, by forming NETs (NETosis), neutrophils can bind, disarm, and kill microbes independent of phagocytic uptake. These functions are achieved through the release of highly concentrated antimicrobial components including proteins from granules and powerful histone proteins from the nucleus. In addition to their possible antimicrobial properties, NETs may serve as a physical barrier that prevents further spread of pathogens. Trapping of bacteria may be a particularly important role for NETs in sepsis, where NETs are formed within blood vessels. Finally, NET formation has been demonstrated to augment macrophage bactericidal activity during infection. Recently, NETs have been shown to play a role in inflammatory diseases, as NETs could be detected in preeclampsia, a pregnancy-related inflammatory disorder in which neutrophils are known to be activated. Neutrophil NET formation may also impact cardiovascular disease, as NETs may influence thrombus formation in coronary arteries. NETs are now known to exhibit pro-thrombotic effects both in vitro and in vivo. More recently, in 2020 NETs were implicated in the formation of blood clots in cases of severe COVID-19.
== Animal tissue == Animal tissues are grouped into four basic types: connective, muscle, nervous, and epithelial. Organs are formed by the functional grouping together of two or more different tissue types. While most animals can generally be considered to contain the four tissue types, the manifestation of these tissues can differ depending on the type of organism. For example, the origin of the cells comprising a particular tissue type may differ developmentally for different classifications of animals. Tissue appeared for the first time in the diploblasts, but modern forms only appeared in triploblasts. The epithelium in all animals is derived from the ectoderm and endoderm (or their precursor in sponges), with a small contribution from the mesoderm, forming the endothelium, a specialized type of epithelium that composes the vasculature. By contrast, a true epithelial tissue is present only in a single layer of cells held together via occluding junctions called tight junctions, to create a selectively permeable barrier. This tissue covers all organismal surfaces that come in contact with the external environment such as the skin, the airways, and the digestive tract. It serves functions of protection, secretion, and absorption, and is separated from other tissues below by a basal lamina. The connective tissue and the muscular are derived from the mesoderm. The nervous tissue is derived from the ectoderm.
== Causes == Any form of muscle damage of sufficient severity can cause rhabdomyolysis. Multiple causes can be present simultaneously in one person. Some have an underlying muscle condition, usually hereditary, that makes them more prone to rhabdomyolysis.
Sources: en.wikipedia.org
On 14 February, Lula, alongside the Governor of Bahia Jerônimo Rodrigues, the Chief of Staff of the Presidency Rui Costa, the President of the Caixa Econômica Federal Maria Rita Serrano, the transport minister Renan Filho, the Minister of Cities Jader Filho, as well as state and municipal authorities (such as the mayor of the city and federal/state deputies from Bahia), announced the return of the Minha Casa, Minha Vida programme during a visit to the city of Santo Amaro, Bahia; the programme will replace the Bolsonaro government's Casa Verde e Amarela programme (which in turn had replaced Lula's first Minha Casa, Minha Vida, created during his previous presidency), the programme is expected to create over 2 million houses for the low-income population by the end of 2026 (the last year of Lula's presidency). The programme was also restructured, with the proposal to serve families with a monthly income of up to R$8,000 in urban areas, and an annual income of up to R$96,000 in rural areas. In order to reduce the housing deficit, in September 2023, an ordinance was published that exempted beneficiaries of Bolsa Família and the Continuous Installment Benefit from paying installments on properties purchased under the programme.
=== Common PTMs by frequency === In 2011, statistics of each post-translational modification experimentally and putatively detected have been compiled using proteome-wide information from the Swiss-Prot database. The 10 most common experimentally found modifications were as follows:
"Our knowledge of the physical and geometrical properties of crystals is now very complete, but their relations to chemical constitution and composition are as yet but little known." After 1912 crystallography would develop dramatically with the widespread adoption of X-ray diffraction to determine crystal structures.
Tissue samples of the St. Augustine Monster were re-examined in 2004 for comparison with the more recently discovered Chilean Blob. Sections were observed with an electron microscope, underwent biochemical analyses, and DNA extraction was attempted but extraction of useful DNA from the sample failed. The results of the study confirmed the findings in the 1995 analysis (Pierce et al. 1995) that the blobs were made of collagen, and were definitively the remains of whale carcasses.
XCMS Online is a cloud version of the original eXtensible Computational Mass Spectrometry (XCMS) technology (a bioinformatics software designed for statistical analysis of mass spectrometry data), created by the Siuzdak Lab at Scripps Research. XCMS introduced the concept of nonlinear retention time alignment that allowed for the statistical assessment of the detected peaks across LCMS and GCMS datasets. XCMS Online was designed to facilitate XCMS analyses through a cloud portal and as a more straightforward (non command driven) way to analyze, visualize and share untargeted metabolomic data. Further to this, the combination of XCMS and METLIN with 960,000 authentic standards, allows for the identification of known molecules using METLIN's tandem mass spectrometry data, and enables the identification of unknown (uncharacterized molecules) via similarity searching of tandem mass spectrometry data. XCMS Online has also become a systems biology tool for integrating different omic data sets. As of January 2021, the XCMSOnline - METLIN platform has over 44,000 registered users. XCMS - METLIN was recognized in 2023 as the year's top analytical innovation. XCMS Online works by comparing groups of raw or preprocessed metabolomic data to discover metabolites using methods such as nonlinear retention time alignment and feature detection & matching. Once analysis is complete the data can be viewed several different ways including via bubble plots, heat maps, chromatograms, and box plots. In addition, XCMS Online is integrated with METLIN, a large metabolite database.
Sources: en.wikipedia.org
The botched embalming of Pope Pius XII (1876–1958; pope 1939–1958) by a charlatan doctor – which only sped up the rate of decomposition – led to his body turning black and his nose falling off while lying in state, and the body disintegrated in the coffin. The Swiss Guards stationed around Pius XII's body were forced to change shifts every 10 to 15 minutes, since the body's odor caused some guards to pass out. The doctor who performed the embalming had also taken photos of the pontiff in his death throes, intending to sell them to tabloids. The Italian tabloids refused to buy the photos, and the doctor was banned from entering the Vatican City-State by John XXIII, who furthermore prohibited any photography of a deceased pope until the body is properly vested and laid out. Charles XII (1682–1718) is one of several Swedish kings to have been embalmed. When Charles XII's sarcophagus was opened in 1917, his features were still recognizable, almost 200 years after his death. Photographs of his remains clearly show the gunshot wound to his head leading to his death. The body of Pope John XXIII (1881–1963; pope 1958–1963) is on display on an altar on the main floor of the Basilica of Saint Peter after having been exhumed from the grottoes beneath the main altar and has retained an extremely well-preserved state. If a body's remains do not decompose, contrary to expectations, it is often treated as a miracle. However, the case of John XXIII's body did not enjoy the same acclamation, as it was held to have been due to embalming and adipocere formation.
== Experiments on seismic metamaterials == In 2012, researchers held an experimental field-test near Grenoble, France, with the aim to highlight analogy with phononic crystals. At the geophysics scale, in a forest in the Landes region of France in 2016, an ambitious seismic experiment called the METAFORET experiment demonstrated that trees could significantly modify the surface wavefield due to their coupled resonances when arranged at a subwavelength scale. Actual use of trees for earthquake protection is not feasible, since tree heights of 260–300 feet (79–91 m) are required to dampen waves produced by earthquakes, and the species of trees, such as redwoods, that are capable of reaching this height range when mature are slow-growing. A follow-up field experiment called the META-WT experiment was performed in the Nauen wind farm. This for the first time demonstrated that, at the city scale, collective resonance of wind-turbine structures can modify seismic waves propagating through it. These new observations have implications for seismic hazard in a city where dense urban structures like tall buildings can strongly modify the wavefield.
The liver is the only human internal organ capable of natural regeneration of lost tissue; as little as 25% of a liver can regenerate into a whole liver. This is, however, not true regeneration but rather compensatory growth in mammals. The lobes that are removed do not regrow and the growth of the liver is a restoration of function, not the original form. This contrasts with true regeneration where both original function and form are restored. In some other species, such as zebrafish, the liver undergoes true regeneration by restoring both shape and size of the organ. In the liver, large areas of the tissues are formed but for the formation of new cells there must be sufficient amount of material so the circulation of the blood becomes more active. This is predominantly due to the hepatocytes re-entering the cell cycle. That is, the hepatocytes go from the quiescent G0 phase to the G1 phase and undergo mitosis. This process is activated by the p75 receptors. There is also some evidence of bipotential stem cells, called hepatic oval cells or ovalocytes (not to be confused with oval red blood cells of ovalocytosis), which are thought to reside in the canals of Hering. These cells can differentiate into either hepatocytes or cholangiocytes. Cholangiocytes are the epithelial lining cells of the bile ducts. They are cuboidal epithelium in the small interlobular bile ducts, but become columnar and mucus secreting in larger bile ducts approaching the porta hepatis and the extrahepatic ducts.
In a separate study of rehabilitative strength training following immobilization, creatine supplementation was associated with increased muscle MRF4 protein expression; however, whether changes in MRF4 directly mediate myonuclear accretion or hypertrophy remains uncertain.
If, as may well happen, there should be created in our own lifetime by the banks of the Jordan a Jewish State under the protection of the British Crown which might comprise three or four millions of Jews, an event will have occurred in the history of the world which would from every point of view be beneficial. At the 22 June 1921 meeting of the Imperial Cabinet, Churchill was asked by Arthur Meighen, the Canadian Prime Minister, about the meaning of the national home. Churchill said "If in the course of many years they become a majority in the country, they naturally would take it over ... pro rata with the Arab. We made an equal pledge that we would not turn the Arab off his land or invade his political and social rights".
Sources: en.wikipedia.org
It is a synthetic peptide that activates both the GIP and GLP-1 receptors, making it a dual agonist. Approved products are given by injection rather than by mouth. It is not a small molecule and does not belong to the older sulfonylurea or thiazolidinedione families.
Engaging two receptors recruits signaling pathways that only partly coincide. This can shift the magnitude of effects on insulin release, glucagon levels and appetite relative to selective agents. Whether the pairing delivers benefits beyond a simple sum of the two is still debated in the literature.
The proportional contribution of each receptor to observed clinical effects has not been fully separated. Long-term consequences of continuous dual stimulation are likewise unclear. Investigators continue to probe these points through laboratory and clinical work.
建议在低温、避光、干燥环境中密封保存，常见条件为 2 至 8 摄氏度，长期存放可置于更低温度。应避免反复冻融，并尽量减少容器开启次数。