Everything below concerns aggregation. We keep the language plain, cite what the science says, and separate well-supported claims from open questions.
Last reviewed on 2026-03-24. Where a claim depends on a specific study, the study is described rather than over-claimed.
The company that developed the compound filed it as a long-acting analogue, and it gained first approval in 2017 for type 2 diabetes. Later authorisations from several regulators extended the indication to chronic weight management, and the World Health Organization added the glucagon-like peptide-1 receptor agonist drug class to its model list of essential medicines in 2023. Production uses solid-phase peptide synthesis followed by side-chain conjugation and chromatographic purification. Supply constraints and cost differences across regions are well documented. Literature on long-term outcomes continues to grow, with many trials reporting surrogate endpoints rather than hard clinical endpoints.
Semaglutide is a synthetic peptide of thirty-one amino acids that shares roughly ninety-four percent sequence identity with human glucagon-like peptide-1. Two substitutions resist enzymatic cleavage by dipeptidyl peptidase-4, and a fatty diacid side chain attached through a linker promotes binding to serum albumin. That albumin binding slows renal clearance and extends the circulating half-life from minutes to approximately one week. The structural changes are well established in the published literature. Whether the same modifications affect receptor signalling bias in ways that matter clinically remains an open question.
Pharmacological activity arises from agonism at the glucagon-like peptide-1 receptor, a G protein-coupled receptor expressed in the pancreas, the gastrointestinal tract, and the brainstem. Receptor activation raises intracellular cyclic adenosine monophosphate and enhances insulin release in a glucose-dependent manner, an effect that diminishes when blood glucose concentration is low. Other effects include slowed gastric emptying and hypothalamic satiety signalling. These pathways are described well. Receptor desensitisation rates across tissues, relative to the endogenous hormone, are still under investigation, and reported findings differ between laboratories.
Native GLP-1 is degraded rapidly by dipeptidyl peptidase-4. Semaglutide resists this cleavage because alanine at position 8 is replaced by alpha-aminoisobutyric acid. A second substitution at position 34 introduces arginine, which further stabilizes the peptide. The most distinctive modification is a spacer and C18 fatty diacid attached at lysine 26, enabling strong albumin affinity. These three changes together produce a half-life measured in days rather than minutes, and the same structural logic underlies other long-acting analogs in this class.
Semaglutide is a synthetic peptide analog of glucagon-like peptide-1, a hormone released from intestinal L-cells after food intake. It contains 31 amino acids and differs from native GLP-1 through modifications that slow enzymatic breakdown. The peptide was developed to extend the short circulating half-life of endogenous GLP-1, which is measured in minutes. Researchers introduced the compound in the early 2010s. Two backbone changes and a fatty acid side chain define its structure, distinguishing it from earlier GLP-1 receptor agonists.
| Property | Value | Notes |
|---|---|---|
| Molecular class | 31-amino-acid peptide | Modified glucagon-like peptide-1 analogue |
| Molecular mass | approximately 4114 Da | Calculated for the free peptide backbone |
| Appearance | white to off-white powder | Typical of purified lyophilised peptide batches |
| Solubility class | freely soluble in water | Aqueous solubility improves at slightly alkaline pH |
| Typical storage | -20 degrees Celsius, dry, dark | Protect from repeated freeze-thaw cycles |
Two structural features account for the prolonged half-life of semaglutide. A modified amino acid at position 8 resists cleavage by dipeptidyl peptidase-4, the enzyme that rapidly degrades native GLP-1. A fatty diacid side chain binds serum albumin, which limits renal clearance and protects the peptide from enzymatic breakdown. These modifications yield a plasma half-life of approximately one week in humans, allowing once-weekly administration. The relationship between plasma concentration and clinical effect varies between individuals, and sources of that variability are still being characterized.
Semaglutide is a synthetic peptide analog of glucagon-like peptide-1 (GLP-1), a hormone released from intestinal L-cells after food intake. The compound belongs to the incretin mimetic class and acts at GLP-1 receptors distributed across pancreatic, gastrointestinal, cardiovascular, and central nervous system tissues. Compared with native GLP-1, the molecule carries structural changes that extend its activity from minutes to roughly one week. It is studied for glycemic control in type 2 diabetes and for weight management, and its effects on cardiovascular and other outcomes remain active research areas.
Receptor binding triggers G protein signaling that raises intracellular cyclic AMP in pancreatic beta cells. Insulin release follows in a glucose-dependent manner, so secretion increases when blood glucose is elevated and diminishes when it is not. The same signaling suppresses glucagon release from alpha cells and slows gastric emptying, which blunts the post-meal glucose rise. In the brain, receptor activation in regions such as the arcuate nucleus is associated with reduced appetite and lower energy intake. How much each of these effects contributes to overall weight change is not fully settled.
Peptide degradation follows several routes. Hydrolysis cleaves the backbone at susceptible residues, oxidation targets methionine and tryptophan side chains, and aggregation produces higher-molecular-weight species that are difficult to reverse. Light exposure accelerates oxidation, which is why amber glass or opaque secondary packaging is common. Repeated freeze-thaw cycles promote aggregation and are best avoided. Stability-indicating methods detect these changes before they become visible.
Quality control for research material typically involves reversed-phase HPLC for purity and identity, mass spectrometry for molecular weight confirmation, and Karl Fischer titration for residual water content. Peptide content is often reported as the mass of actual peptide rather than total powder mass, since counterions and water contribute to the latter. A certificate of analysis should list the method used for each specification. Limits and acceptance criteria vary by supplier and by intended application.
Handling practices center on minimizing contamination and adsorption. Lyophilized peptide tends to accumulate static charge, so weighing is done with antistatic measures and calibrated balances. Reconstitution with appropriate solvent should be gentle, avoiding vigorous vortexing that generates foam and shear. Solutions are typically aliquoted before freezing to reduce repeated temperature cycling. Personal protective equipment and a fume hood are standard for powder handling.
The most significant evolutionary theory before Darwin's was that of Jean-Baptiste Lamarck; based on the inheritance of acquired characteristics (an inheritance mechanism that was widely accepted until the 20th century), it described a chain of development stretching from the lowliest microbe to humans. The British naturalist Charles Darwin, combining the biogeographical approach of Humboldt, the uniformitarian geology of Lyell, Thomas Malthus's writings on population growth, and his own morphological expertise, created a more successful evolutionary theory based on natural selection; similar evidence led Alfred Russel Wallace to independently reach the same conclusions. The 1859 publication of Darwin's theory in On the Origin of Species by Means of Natural Selection, or the Preservation of Favoured Races in the Struggle for Life is often considered the central event in the history of modern biology. Darwin's established credibility as a naturalist, the sober tone of the work, and most of all the sheer strength and volume of evidence presented, allowed Origin to succeed where previous evolutionary works such as the anonymous Vestiges of Creation had failed. Most scientists were convinced of evolution and common descent by the end of the 19th century. However, natural selection would not be accepted as the primary mechanism of evolution until well into the 20th century, as most contemporary theories of heredity seemed incompatible with the inheritance of random variation.
What distinguishes the androgen backdoor from the classical pathway is whether 5α-reduction initiates or terminates the pathway. In the backdoor pathway, 5α-reduction of progesterone (P4) or 17α-hydroxyprogesterone (17OHP) occurs at or near the beginning of the pathway respectively. Conversely, in the classical pathway, 5α-reduction is the final step, where testosterone is converted into dihydrotestosterone (DHT). The backdoor pathway splits into two subpathways at P4, proceeding through either 17OHP or 5α-DHP before merging again at 5α-Pdiol. The biosynthetic intermediate 5α-Pdiol in turn is converted into DHT in two chemical steps.
A white coat ceremony is a relatively new ritual that marks one's entrance into medical school and, more recently, into a number of health-related schools and professions. It originated at University of Chicago's Pritzker School of Medicine in 1989 and involves a formal "robing" or "cloaking" in white lab coats.
Erinacines are natural substances isolated from the mycelium of Hericium erinaceus (lion's mane mushroom). They belong to the group of cyathin diterpenoids (erinacines A–K, P, Q, S, U) and are subjects of pharmacological research, which largely focuses on the benefits of erinacine on the brain. All erinacines are able to readily cross the blood–brain barrier in vivo, which largely influences the bioavailability of the compounds in the brain.
Dendritic cell therapy provokes anti-tumor responses by causing dendritic cells to present tumor antigens to lymphocytes, which activates them, priming them to kill other cells that present the antigen. Dendritic cells are antigen-presenting cells (APCs) in the mammalian immune system. In cancer treatment, they aid cancer antigen targeting. The only approved cellular cancer therapy based on dendritic cells is sipuleucel-T. One method of inducing dendritic cells to present tumor antigens is by vaccination with autologous tumor lysates or short peptides (small parts of the protein that correspond to the protein antigens on cancer cells). These peptides are often given in combination with adjuvants (highly immunogenic substances) to increase the immune and anti-tumor responses. Other adjuvants include proteins or other chemicals that attract and/or activate dendritic cells, such as granulocyte-macrophage colony-stimulating factor (GM-CSF). The most common sources of antigens used for dendritic cell vaccine in glioblastoma (GBM) as an aggressive brain tumor were whole tumor lysate, CMV antigen RNA and tumor-associated peptides like EGFRvIII. Dendritic cells can also be activated in vivo by making tumor cells express GM-CSF. This can be achieved by either genetically engineering tumor cells to produce GM-CSF or by infecting tumor cells with an oncolytic virus that expresses GM-CSF. Another strategy is to remove dendritic cells from the blood of a patient and activate them outside the body.
Sources: en.wikipedia.org
The Culture is a fictional interstellar post-scarcity society created by the Scottish writer Iain M. Banks and features in a number of his space opera novels and works of short fiction, collectively called the Culture series. The Culture is composed primarily of humanoid aliens, artificial intelligences (A.I.), and a number of other sentient life forms. The A.I. intelligence covers a spectrum; simple programs performing a specific function (e.g. controlling spacesuits), human-equivalent drones and hyper-intelligent Minds who organise and oversee the society. Beyond scarcity, the Culture has no need for money; instead, Minds organise society to maximise the well-being of its citizenry. The protagonists, almost always humanoids, are generally those who have chosen to work for the Culture's diplomatic or espionage organs and interact with other civilisations whose citizens act under different ideologies, morals, and technologies. The Culture generally has more advanced technology relative to most other civilisations it shares the galaxy with. Most of the Culture's citizens do not live on planets but in artificial habitats such as orbitals and ships, the largest of which are home to billions of individuals. The Culture's citizens have been genetically enhanced to live for as long as they desire and have modified mental control over their physiology, including the ability to introduce a variety of psychoactive drugs into their systems, change biological sex, or switch off pain at will.
The efficacy of quinacrine was assessed in a rigorous clinical trial in the UK and the results were published in Lancet Neurology, and concluded that quinacrine had no measurable effect on the clinical course of CJD. Astemizole, a medication approved for human use, has been found to have anti-prion activity and may lead to a treatment for Creutzfeldt–Jakob disease. A monoclonal antibody (code name PRN100) targeting the prion protein (PrP) was given to six people with Creutzfeldt–Jakob disease in an early-stage clinical trial conducted from 2018 to 2022. The treatment appeared to be well-tolerated and was able to access the brain, where it might have helped to clear PrPC. While the treated patients still showed progressive neurological decline, and while none of them survived longer than expected from the normal course of the disease, the scientists at University College London who conducted the study see these early-stage results as encouraging and suggest conducting a larger study, ideally at the earliest possible intervention.
== Pharmacology == The drug is a selective KOR antagonist and shows approximately 10- to 20-fold higher affinity for the KOR (Ki = 1–3 nM) over the μ-opioid receptor (MOR) (Ki = 10–64 nM) and has negligible affinity for the δ-opioid receptor (DOR) (Ki > 4,000 nM). It is a "short-acting" or non-inactivating antagonist of the KOR (as opposed to irreversible antagonists like JDTic). Although originally characterized as a KOR neutral antagonist however, subsequent research revealed in 2020 that PF-04455242 is actually only a moderately efficacious partial antagonist of the KOR (Imax ≈ 50%). In any case, the drug reversed the analgesic and prolactin-elevating effects of the KOR agonist spiradoline in animals, showed efficacy in animal models predictive of antidepressant activity, and reversed stress-induced reinstatement of cocaine-seeking behavior. However, PF-04455242 also showed a variety of other weak off-target activities.
In 2018, McGregor starred as the adult version of the titular character in Christopher Robin, a live-action adaptation of Disney's Winnie the Pooh franchise directed by Marc Forster and starred alongside Hayley Atwell. In 2019, McGregor starred as the older Danny Torrance in Doctor Sleep, the film adaptation of Stephen King's novel of the same name. In 2020, he appeared opposite Margot Robbie in Warner Bros.' DC Comics film Birds of Prey (and the Fantabulous Emancipation of One Harley Quinn), directed by Cathy Yan, as the main villain Roman Sionis / Black Mask. On 23 August 2019, Lucasfilm announced that McGregor would reprise his role as Obi-Wan Kenobi in a new Star Wars television series, which was released on Disney+ in 2022. In 2021, McGregor played the American fashion designer Halston in the eponymously titled miniseries for Netflix, based on the candid biography Simply Halston by journalist Steven Gaines. McGregor was also billed as executive producer, jointly with Ryan Murphy. In 2022, McGregor voiced Sebastián J. Cricket, the conscience and narrator, in Pinocchio. The film was directed by Guillermo del Toro and premiered on Netflix. In September 2024, McGregor received his star on the Hollywood Walk of Fame. In 2026, he had a starring role as Greg Platt in the science fiction survival film The End of Oak Street.
Construction materials The chambers are generally built of brick masonry, or hollow cement-concrete slabs. Sheet metal or prefabricated aluminium in a double-walled construction with sandwiched thermal insulation, such as glass wool or polyurethane foams, are materials that are also used in some modern timber ovens. However, brick masonry chambers, with lime and (mortar) plaster on the inside and painted with impermeable coatings, are used widely and have been found to be satisfactory for many applications. Heating Heating is usually carried out by steam heat exchangers and pipes of various configurations (e.g. plain, or finned (transverse or longitudinal) tubes) or by large flue pipes through which hot gases from a wood-burning furnace are passed. Only occasionally is electricity or gas employed for heating. Humidification Humidification is commonly accomplished by introducing live steam into the kiln through a steam spray pipe. In order to limit and control the humidity of the air when large quantities of moisture are being rapidly evaporated from the timber, there is normally a provision for ventilation of the chamber in all types of kilns. Air circulation Air circulation is the means for carrying the heat to and the moisture away from all parts of a load. Forced circulation kilns are most common, where the air is circulated by means of fans or blowers, which may be installed outside the kiln chamber (external fan kiln) or inside it (internal fan kiln).
Sources: en.wikipedia.org
South Africa gradually became locked in a conventional arms race with Angola; each side argued that it had to match the increased force available to the other. To counter the appearance of advanced MiG-23 and SU-22 fighters in Angola, for instance, South Africa began development on two sophisticated fighter aircraft of its own, the Atlas Cheetah and the Atlas Carver. Both programmes would consume billions of rand.
nucleotidase Any of a class of phosphoric monoester hydrolase enzymes which catalyze the hydrolysis of a nucleotide into a nucleoside and orthophosphate. Such enzymes may or may not distinguish ribonucleotides from deoxyribonucleotides, i.e. their function may not be sugar-specific.
== Toxicity == The toxicity of organomercury compounds presents both dangers and benefits. Dimethylmercury in particular is notoriously toxic, but found use as an antifungal agent and insecticide. Merbromin and phenylmercuric borate are used as topical antiseptics, while thimerosal is safely used as a preservative for vaccines and antitoxins.
=== 15 July === The Russian-installed governor of Sevastopol claimed that a house was damaged by falling drone debris near Cape Fiolent. The Russian defence ministry claimed that six drones were shot down over Crimea. The HUR and volunteer hackers carried out a cyberattack on websites in Russia belonging to entities involved in the war effort against Ukraine. In Russia, the governor of Lipetsk Oblast claimed that an electrical substation was struck by a drone in Stanovlyansky District, while the governor of Bryansk Oblast claimed that 15 drones were shot down over five districts. Lithuania and Vilnius Combined Heat and Power Plant gave Ukraine equipment for a thermal power plant.
Petersburg, Florida, was subject to an FCA claim that resulted in a total judgment of US$1.179 million on 214 fraudulent claims to Medicare that totaled US$755.54 stemming from the lack of a CLIA certificate. The oncology practice had its own CLIA certificate and acquired another oncology clinic with an in-house lab, but did not obtain the clinic's CLIA license, so the existing CLIA certificate did not cover the new practice. Because the lab at the newly acquired oncology practice lacked a proper CLIA certificate, reimbursement was denied. The practice opted to resubmit the bills to fraudulently claim the tests were performed at an office with a valid CLIA certificate. In doing so 214 times, the federal government suffered $755.54 in damages. The court trebled the damages to $2,266.62 and imposed the minimum statutory penalty of $5,500 per violation for each of the 214 violations. The Eleventh circuit noted that "[s]eeing a judgment of $1.179 million based on $755.54 in actual damages may raise an eyebrow," noting that "[f]raud harms the United States in ways untethered to the value of any ultimate payment" and that "[i]n the context of the FCA, we also consider the deterrent effect of a monetary award."
Sources: en.wikipedia.org
It is a glucagon-like peptide-1 receptor agonist, often grouped with the incretin mimetics. Its backbone is modified from the human hormone to resist enzymatic degradation and to bind albumin. These two features distinguish it from the native peptide.
No. It shares high sequence identity but carries non-natural modifications that alter its stability and clearance. The naturally occurring hormone is broken down within minutes, while the synthetic analogue circulates far longer.
Attachment to serum albumin reduces renal filtration of the peptide and shields it from enzymatic breakdown. The consequence is a much longer interval between administrations than unmodified peptides allow. The precise contribution of binding affinity to overall duration is still being quantified.
It is a synthetic analog of GLP-1 produced through medicinal chemistry to resist enzymatic degradation. The design goal was longer circulation than the native hormone.