A team from the University of Chicago has announced the first evidence for “quantum superchemistry”—a phenomenon where particles in the same quantum state undergo collective accelerated reactions. The effect had been predicted, but never observed in the laboratory.
Sandwich compounds are special chemical compounds used as basic building blocks in organometallic chemistry. So far, their structure has always been linear.
Recently, researchers of Karlsruhe Institute of Technology (KIT) and the University of Marburg were the first to make stacked sandwich complexes form a nano-sized ring. Physical and other properties of these cyclocene structures will now be further investigated. The researchers report their findings in Nature.
Sandwich complexes were developed about 70 years ago and have a sandwich-like structure. Two flat aromatic organic rings (the “slices of bread”) are filled with a single, central metal atom in between. Like the slices of bread, both rings are arranged in parallel. Adding further layers of “bread” and “filling” produces triple or multiple sandwiches.
A team of scientists led by the University of Oxford have achieved a significant breakthrough in detecting modifications on protein structures. The method, published in Nature Nanotechnology, employs innovative nanopore technology to identify structural variations at the single-molecule level, even deep within long protein chains.
Human cells contain approximately 20,000 protein-encoding genes. However, the actual number of proteins observed in cells is far greater, with over 1,000,000 different structures known. These variants are generated through a process known as post-translational modification (PTM), which occurs after a protein has been transcribed from DNA.
PTM introduces structural changes such as the addition of chemical groups or carbohydrate chains to the individual amino acids that make up proteins. This results in hundreds of possible variations for the same protein chain.
Fuel cells are compact energy conversion units that utilize clean energy sources like hydrogen and convert them into electricity through a series of oxidation–reduction reactions. Specifically, proton exchange membrane fuel cells (PEMFCs), an integral part of electric vehicles, utilize proton-conductive membranes for operation. Unfortunately, these membranes suffer from a trade-off between high durability and high ion conductivity, affecting the lifetime and performance of PEMFCs.
To overcome this issue, scientists have synthesized chemically and physically modified perfluorosulfonic acid polymer membranes, such as Nafion HP, Nafion XL, and Gore-Select, which have proven to be much more durable than unmodified membranes conventionally employed in fuel-cell operations.
Unfortunately, none of the existing proton-conductive membranes have fulfilled the highly challenging technical target—passing an accelerated durability test or a combined chemical and mechanical test—set by the U.S. Department of Energy (DOE) to facilitate their use in automobile fuel cells by 2025.
Assessments of the health impacts of the non-sugar sweetener aspartame are released today by the International Agency for Research on Cancer (IARC) and the World Health Organization (WHO) and the Food and Agriculture Organization (FAO) Joint Expert Committee on Food Additives (JECFA). Citing “limited evidence” for carcinogenicity in humans, IARC classified aspartame as possibly carcinogenic to humans (IARC Group 2B) and JECFA reaffirmed the acceptable daily intake of 40 mg/kg body weight. Aspartame is an artificial (chemical) sweetener widely used in various food and beverage products since the 1980s, including diet drinks, chewing gum, gelatin, ice cream, dairy products such as yogurt, breakfast cereal, toothpaste and medications such as cough drops and chewable vitamins.
https://www.who.int/news/item/14-07-2023-aspartame-h…s-released
An expert panel found a potential association with liver cancer, but too little research exists to assume a causal connection. For now, the WHO left current consumption guidelines unchanged.
Local and federal authorities spent months investigating a warehouse in Fresno County, California, that they suspect was home to an illegal, unlicensed laboratory full of lab mice, medical waste and hazardous materials.
The Fresno County Public Health Department has been “evaluating and assessing the activities of an unlicensed laboratory” in Reedley, the health department’s assistant director, Joe Prado, said in a statement Thursday. All of the biological agents were destroyed by July 7 following a legal abatement process by the agency.
“The evaluation required coordination and collaboration with multiple federal and state agencies to determine and classify biological and chemical contents onsite, in addition to assessing jurisdictional authority under this unique situation,” Prado said.
Chemical structures called cyclopropanes can increase the potency and fine-tune the properties of many drugs, but traditional methods to create this structure only work with certain molecules and require highly reactive—potentially explosive—ingredients.
Now, a team of researchers from Penn State has identified and demonstrated a safe, efficient and practical way to create cyclopropanes on a wide variety of molecules using a previously undescribed chemical process. With additional development, the new method—described in a paper publishing Aug. 4 in the journal Science —could transform how this important process occurs during drug development and creation.
Cyclopropanes are a key feature in many drugs currently approved by the U.S. Food and Drug Administration, including those used to treat COVID-19, asthma, hepatitis C, and HIV/AIDs. These structures can increase a drug’s potency, alter its ability to dissolve in the body, minimize its interactions with unintended targets, and otherwise fine-tune performance. Cyclopropanes are a ring of three connected carbon atoms, with one carbon attached to the rest of the drug molecule and the other two each attached to two hydrogen atoms.
Thinking of X-rays might trigger memories of broken bones or dental check-ups. But this extremely energetic light can show us more than just our bones: it is also used to study the molecular world, even biochemical reactions in real-time. One issue, though, is that researchers have never been able to study a single atom with X-rays. Until now.
Scientists have been able to characterize a single atom using X-rays. Not only were they able to distinguish the type of atoms they were seeing (there were two different ones), but they also managed to study the chemical behavior these atoms were showing.
“Atoms can be routinely imaged with scanning probe microscopes, but without X-rays, one cannot tell what they are made of. We can now detect exactly the type of a particular atom, one atom-at-a-time, and can simultaneously measure its chemical state,” senior author Professor Saw Wai Hla, from the University of Ohio and the Argonne National Laboratory, said in a statement.
Each cell in the body stores its genetic information in DNA in a stable and protected form that is readily accessible for the cell to carry on its activities. Nevertheless, mutations—changes in genetic information—occur throughout the human genome and can have a powerful influence on human health and evolution.
“Our team is interested in a classical question about mutation—why do mutation rates in the genome vary so tremendously from one DNA location to another? We just do not have a clear understanding of why this occurs,” said Dr. Md. Abul Hassan Samee, assistant professor of integrative physiology at Baylor College of Medicine and corresponding author of the work.
Previous studies have shown that the DNA sequences flanking a mutated position—the sequence context—play a strong role in the mutation rate. “But this explanation still leaves unanswered questions,” Samee said. “For example, one type of mutation occurs frequently in a specific sequence context while a different type of mutation occurs infrequently in that same sequence context. So, we think that a different mechanism could explain how mutation rates vary in the genome. We know that each building block or base that makes up a DNA sequence has its own 3D chemical shape. We proposed, therefore, that there is a connection between DNA shape and mutations rates, and this paper shows that our idea was correct.”
A process of surgically joining the circulatory systems of a young and old mouse slows the aging process at the cellular level and lengthens the lifespan of the older animal by up to 10%.
Published in the journal Nature Aging, a study led by researchers at Duke University Medical Center in Durham, North Carolina, found that the longer the animals shared circulation, the longer the anti-aging benefits lasted once the two were no longer connected.
The findings suggest that the young benefit from a cocktail of components and chemicals in their blood that contributes to vitality, and these factors could potentially be isolated as therapies to speed healing, rejuvenate the body, and add years to an older individual’s life.
