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Category: chemistry – Page 165

An unusual quasicrystal has been discovered by a team from the Martin Luther University Halle-Wittenberg (MLU), the University of Sheffield and Xi’an Jiaotong University. It has a dodecagonal honeycomb structure that has never been seen before. Until now, similar quasicrystals were only known to come in a solid—not liquid—form. The team presents its results in the journal Nature Chemistry.

Quasicrystals have a special structure. They have a regular pattern similar to normal crystals, however, in normal crystals, the arrangement of the individual components is repeated over and over at . In the case of quasicrystals, the components do not fit together in such a periodic pattern. This special structure gives them special properties that normal crystals do not have.

The newly discovered consists of dodecagons, which in turn are made up of a mixture of triangular, square and, for the first time, trapezoidal shaped cells. These are generated from the self-assembly of “T-shaped” molecules. “We have discovered a perfectly ordered liquid quasicrystal. Such a material has never been seen before,” says chemist Professor Carsten Tschierske at MLU.

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In a result decades in the making, Los Alamos scientists have achieved light amplification with electrically driven devices based on solution-cast semiconductor nanocrystals—tiny specs of semiconductor matter made via chemical synthesis and often called colloidal quantum dots.

This demonstration, reported in the journal Nature, opens the door to a completely new class of electrically pumped lasing devices—highly flexible, solution-processable laser diodes that can be prepared on any crystalline or non-crystalline substrate without the need for sophisticated vacuum-based growth techniques or a highly controlled clean-room environment.

“The capabilities to attain light amplification with electrically driven colloidal have emerged from decades of our previous research into syntheses of nanocrystals, their photophysical properties and optical and electrical design of quantum dot devices,” said Victor Klimov, Laboratory Fellow and leader of the quantum dot research initiative.

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Root canal treatment removes the infection and bacteria from the core of a tooth — the pulp chamber. These bacteria are often present within the canals of the teeth. However, proper treatment saves a badly infected natural tooth from needing to be extracted. Sufficient cleaning of the root canals is a key step of RCT. A lack of proper canal debridement can cause bacteria to thrive — a significant cause of RCT failures.

The tooth is washed with antibiotics or other chemicals that kill the bacteria to get rid of the infection. However, some teeth have complex root structures, and conventional ways of cleaning them are not enough to remove all bacteria. That’s one area where dental nanorobots can help. Nanorobots are showing promise in different steps of RCT, even better than traditional ways.

Dental nanorobots, also called nanobots/nanomotors/nano propellers, are designed to reach nooks and crannies within teeth to disinfect even the narrowest and most complex tooth canals during RCT. As the name suggests, nanorobots are microscopic — one-millionth of a millimeter. Dentists need special equipment like electron microscopes to see them. Their tiny size helps them to enter tooth canals and maneuver to depths and through curves not previously accessible.

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Physicists at Delft University of Technology have developed a new technology on a microchip by combining two Nobel Prize-winning methods for the first time. The microchip is capable of accurately measuring distances in materials, which could have applications in areas such as underwater measurement and medical imaging.

The new technology, which utilizes sound vibrations instead of light, could be useful for obtaining high-precision position measurements in materials that are opaque. This breakthrough could result in the development of new methods for monitoring the Earth’s climate and human health. The findings have been published in the journal Nature Communications.

<em>Nature Communications</em> is a peer-reviewed, open-access, multidisciplinary, scientific journal published by Nature Portfolio. It covers the natural sciences, including physics, biology, chemistry, medicine, and earth sciences. It began publishing in 2010 and has editorial offices in London, Berlin, New York City, and Shanghai.

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New research by biotech Integrated Biosciences and scientists from MIT and the Broad Institute of MIT and Harvard has demonstrated the potential of AI in discovering novel senolytic compounds.

Longevity. Technology: Senolytics are small molecules that suppress age-related processes such as fibrosis, inflammation and cancer. They target senescent cells – the so-called ‘zombie’ cells that are no longer dividing, emit toxic chemicals and are a hallmark of aging. Senescent cells have been linked to various age-related diseases, including cancer, cardiovascular disease, diabetes and Alzheimer’s disease, but senolytic compounds can tackle them by selectively inducing apoptosis or programmed cell death in these zombie cells. This new research reduced the number of senescent cells and lowered the expression of senescence-associated genes in aged mice, results which, the authors say “underscore the promise of leveraging deep learning to discover senotherapeutics” [1].

The AI-guided screening of more than 800,000 compounds led to the identification of three drug candidates, which, when compared with senolytics currently under investigation, were found to have comparable efficacy and superior medicinal chemistry properties [1].

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Glycans perform varied and crucial functions in numerous cellular activities. The diverse roles of glycans are matched by their highly complex structures, which derive from differences in composition, branching, regio-and stereochemistry, and modification. This incomparable structural diversity is challenging to the structural analysis of glycans.

Recently, a joint research group led by Prof. Qing Guangyan and Prof. Liang Xinmiao from the Dalian Institute of Chemical Physics (DICP) of the Chinese Academy of Sciences (CAS) has developed a identification method based on single-molecule sensing through a glycan derivatization strategy. The study was published in Nature Communications on March 28.

Identifying and sequencing glycans using nanopore single-molecule techniques has sparked interest; however, it has achieved little progress over the past dozen years. Only a handful of cases that focused on either high molecular weight polysaccharides or some monosaccharides were reported.

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HOUSTON (AP) — Fire erupted at a petrochemical plant in the Houston area Friday, sending nine workers to a hospital and causing a huge plume of smoke visible for miles.

Emergency responders were called to help around 3 p.m. at the Shell facility in Deer Park, a suburb east of Houston. The city of Deer Park said in an advisory that there was no shelter-in-place order for residents.

Harris County Sheriff Ed Gonzalez said earlier in the day that five contracted employees were hospitalized for precautionary reasons, adding that they were not burned. He said they were taken to a hospital due to heat exhaustion and proximity to the fire.

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DEER PARK, Texas (AP) — Fire erupted at a petrochemical plant in the Houston area Friday, leaving five workers hospitalized and sending up a huge plume of smoke visible for miles.

The Harris County Sheriff’s Office said the fire was at a Shell USA Inc. facility in Deer Park, a suburb east of Houston.

Law enforcement received a call to help divert traffic around the plant just after 3 p.m., Harris County Sheriff’s Office spokesman Thomas Gilliland said. The city of Deer Park said in an advisory that there was no shelter-in-place order for residents.

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A small team of chemists at the Russian Academy of Sciences, has found that metal atoms, not nanoparticles, play the key role in catalysts used in fine organic synthesis. In the study, reported in the Journal of the American Chemical Society, the group used multiple types of electron microscopy to track a region of a catalyst during a reaction to learn more about how it was proceeding.

Prior research has shown that there are two main methods for studying a reaction. The first is the most basic: As ingredients are added, the reaction is simply observed and/or measured. This can be facilitated through use of high-speed cameras. This approach will not work with nanoscale reactions, of course. In such cases, chemists use a second method: They attempt to capture the state of all the components before and after the reaction and then compare them to learn more about what happened.

This second approach leaves much to be desired, however, as there is no way to prove that the objects under study correspond with one another. In recent years, have been working on a new approach: Following the action of a single particle during the reaction. This new method has proven to have merit but it has limitations as well—it also cannot be used for reactions that occur in the nanoworld. In this new effort, the researchers used multiple types of electron microscopy coupled with .

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Indigo naturalis is a blue dye in ancient, as well as an extensive used traditional Chinese medicine. It has a wide spectrum of pharmacological properties and can be used to treat numerous ailments such as leukemia, psoriasis, and ulcerative colitis. This article aims to expand our understanding of indigo naturalis in terms of its chemical constituents, pharmacological action and clinical applications.

We searched PubMed, web of science, CNKI, Google academic, Elsevier and other databases with the key words of “Indigo naturalis”, and reviewed and sorted out the modern research of indigo naturalis based on our research results.

We outlined the traditional manufacturing process, chemical composition and quality control of indigo naturalis, systematically reviewed traditional applictions, pharmacological activities and mechanism of indigo naturalis, and summarized its clinical trials about treatment of psoriasis, leukemia and ulcerative colitis.

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