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Category: chemistry – Page 320

Electrons waiting for their turn: New model explains 3D quantum material

Scientists from the Cluster of Excellence ct.qmat—Complexity and Topology in Quantum Matter have developed a new understanding of how electrons behave in strong magnetic fields. Their results explain measurements of electric currents in three-dimensional materials that signal a quantum Hall effect—a phenomenon thus far only associated with two-dimensional metals. This new 3D effect can be the foundation for topological quantum phenomena, which are believed to be particularly robust and therefore promising candidates for extremely powerful quantum technologies. These results have just been published in the scientific journal Nature Communications.

Dr. Tobias Meng and Dr. Johannes Gooth are early career researchers in the Würzburg-Dresdner Cluster of Excellence ct.qmat that researches topological quantum materials since 2019. They could hardly believe the findings of a recent publication in Nature claiming that electrons in the topological zirconium pentatelluride (ZrTe5) move only in two-dimensional planes, despite the fact that the material is three-dimensional. Meng and Gooth therefore started their own research and experiments on the material ZrTe5. Meng from the Technische Universität Dresden (TUD) developed the theoretical model, Gooth from the Max Planck Institute for Chemical Physics of Solids designed the experiments. Seven measurements with different techniques always lead to the same conclusion.

Biologists Construct a “Periodic Table” for Cell Nuclei – And Discover Something Strange, Baffling and Unexpected

One hundred fifty years ago, Dmitri Mendeleev created the periodic table, a system for classifying atoms based on the properties of their nuclei. This week, a team of biologists studying the tree of life has unveiled a new classification system for cell nuclei, and discovered a method for transmuting one type of cell nucleus into another.

The study, which appears this week in the journal Science, emerged from several once-separate efforts. One centered on the DNA Zoo, an international consortium spanning dozens of institutions including Baylor College of Medicine, the National Science Foundation-supported Center for Theoretical Biological Physics (CTBP) at Rice University, the University of Western Australia and SeaWorld.

Scientists on the DNA Zoo team had been working together to classify how chromosomes — which can be several meters long — fold up to fit inside the nuclei of different species from across the tree of life.

Dragonfly: In Situ Exploration of Saturn’s Moon Titan, an Organic Ocean World

Wednesday, May 26 at 8 pm ET, discover what we hope to learn about Saturn’s fascinating moon Titan, featuring planetary scientist Zibi Turtle. Register: https://s.si.edu/2Q58d9N

Saturn’s largest moon, Titan, is an ocean world with a dense atmosphere, abundant complex organic material on its icy surface, and a liquid-water ocean in its interior. The Cassini-Huygens mission revealed Titan to be surprisingly Earth-like, with active geological processes and opportunities for organic material to have mixed with liquid water on the surface in the past. These attributes make Titan a unique destination to seek answers to fundamental questions about what makes a planet or moon habitable and about the pre-biotic chemical processes that led to the development of life here on Earth.
NASA’s upcoming Dragonfly New Frontiers mission is a rotorcraft lander designed to perform long-range in situ investigation of the chemistry and habitability of this fascinating extraterrestrial environment. In this program, Planetary scientist Zibi Turtle from the Johns Hopkins Applied Physics Laboratory will discuss this fascinating new mission: Taking advantage of Titan’s dense atmosphere and low gravity, Dragonfly will fly from place to place, exploring diverse geological settings to measure the compositions of surface materials and observe Titan’s geology and meteorology. Dragonfly will make multidisciplinary science measurements at dozens of sites, traveling ~100 miles during a 3-year mission to characterize Titan’s habitability and to determine how far organic chemistry has progressed in environments that provide key ingredients for life.

The Exploring Space Lecture Series is made possible by the generous support of Aerojet Rocketdyne and United Launch Alliance.

Biologists construct a ‘periodic table’ for cell nuclei

One hundred fifty years ago, Dmitri Mendeleev created the periodic table, a system for classifying atoms based on the properties of their nuclei. This week, a team of biologists studying the tree of life has unveiled a new classification system for cell nuclei and discovered a method for transmuting one type of cell nucleus into another.

The study, which appears this week in the journal Science, emerged from several once-separate efforts. One of these centered on the DNA Zoo, an international consortium spanning dozens of institutions including Baylor College of Medicine, the National Science Foundation-supported Center for Theoretical Biological Physics (CTBP) at Rice University, the University of Western Australia and SeaWorld.

Scientists on the DNA Zoo team had been working together to classify how chromosomes, which can be several meters long, fold up to fit inside the nuclei of different species from across the tree of life.

Dr. Jonathan Chernoff, MD, PhD — Senior VP, Deputy Director, and CSO — Fox Chase Cancer Center

Innovating At The Frontiers Of Cancer Biology — Dr. Jonathan Chernoff MD, PhD, Senior Vice President, Deputy Director, and Chief Scientific Officer, Fox Chase Cancer Center.

Dr. Jonathan Chernoff, MD, PhD, is Senior Vice President, Deputy Director, and Chief Scientific Officer, at Fox Chase Cancer Center (https://www.foxchase.org/) where he coordinates and charts the future course of research for the organization.

The Hospital of Fox Chase Cancer Center and its affiliates (collectively “Fox Chase Cancer Center”), a member of the Temple University Health System, is one of the leading cancer research and treatment centers in the United States. Founded in 1904 in Philadelphia as one of the nation’s first cancer hospitals, Fox Chase was also among the first institutions to be designated a National Cancer Institute Comprehensive Cancer Center in 1974.

Dr. Chernoff joined the staff in 1991 as an associate member and was promoted to member with tenure in 1996. In 2002 he was promoted to be a senior member in Fox Chase Cancer Center’s Basic Science division, the equivalent of a full professor in a university.

A molecular oncologist as well as a board-certified medical oncologist, Dr. Chernoff has a special interest in factors that control cell growth and movement, including oncogenes and anticancer or tumor-suppressor genes, and has made fundamental contributions in this research.

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The number of neurons in Drosophila and mosquito brains

Various insect species serve as valuable model systems for investigating the cellular and molecular mechanisms by which a brain controls sophisticated behaviors. In particular, the nervous system of Drosophila melanogaster has been extensively studied, yet experiments aimed at determining the number of neurons in the Drosophila brain are surprisingly lacking. Using isotropic fractionator coupled with immunohistochemistry, we counted the total number of neuronal and non-neuronal cells in the whole brain, central brain, and optic lobe of Drosophila melanogaster. For comparison, we also counted neuronal populations in three divergent mosquito species: Aedes aegypti, Anopheles coluzzii and Culex quinquefasciatus. The average number of neurons in a whole adult brain was determined to be 199380 ±3400 cells in D. melanogaster, 217910 ±6180 cells in Ae. aegypti, 223020 ± 4650 cells in An. coluzzii and 225911±7220 cells in C. quinquefasciatus. The mean neuronal cell count in the central brain vs. optic lobes for D. melanogaster (101140 ±3650 vs. 107270 ± 2720), Ae. aegypti (109140 ± 3550 vs. 112000 ± 4280), An. coluzzii (105130 ± 3670 vs. 107140 ± 3090), and C. quinquefasciatus (108530 ±7990 vs. 110670 ± 3950) was also estimated. Each insect brain was comprised of 89% ± 2% neurons out of its total cell population. Isotropic fractionation analyses did not identify obvious sexual dimorphism in the neuronal and non-neuronal cell population of these insects. Our study provides experimental evidence for the total number of neurons in Drosophila and mosquito brains.

Citation: Raji JI, Potter CJ (2021) The number of neurons in Drosophila and mosquito brains. PLoS ONE 16: e0250381. https://doi.org/10.1371/journal.pone.

Editor: Matthieu Louis, University of California Santa Barbara, UNITED STATES.

Resetting the biological clock

The biological clock is present in almost all cells of an organism. As more and more evidence emerges that clocks in certain organs could be out of sync, there is a need to investigate and reset these clocks locally. Scientists from the Netherlands and Japan introduced a light-controlled on/off switch to a kinase inhibitor, which affects clock function. This gives them control of the biological clock in cultured cells and explanted tissue. They published their results on 26 May in Nature Communications.

Life on Earth has evolved under a 24-hour cycle of light and dark, hot and cold. “As a result, our cells are synchronized to these 24-hour oscillations,” says Wiktor Szymanski, Professor of Radiological Chemistry at the University Medical Center Groningen. Our circadian clock is regulated by a central controller in the , a region in the brain directly above the optic nerve, but all our cells contain a clock of their own. These clocks consist of an oscillation in the production and breakdown of certain proteins.

Scientists Discover a New Type of Biochemical That Could Be in All Life on Earth

The wonderful mess of molecules that make up living things is so complex, biologists have overlooked an entire class of them – until now. This missed bit of biochemistry is neither rare nor hard to find; it’s just no one had thought to look for it before.

“This is a stunning discovery of an entirely new class of biomolecules,” said Stanford biochemist Carolyn Bertozzi.

“It’s really a bombshell because the discovery suggests that there are biomolecular pathways in the cell that are completely unknown to us.”

Scientists find ultraviolet light may create life-essential chemicals

Circa 2016 o.o!

The theory used to be that hydrocarbons were created in “shocks,” or violent stellar events that cause a lot of turbulence and, with the shock waves, make atoms into ions, which are more likely to combine.

The data from the European Space Agency’s Herschel Space Observatory has since proved that theory wrong. Scientists at Herschel studied the components in the Orion Nebula, mapping the amount, temperature and motions for the carbon-hydrogen molecule (CH), the carbon-hydrogen positive ion (CH+) and their parent molecule: the carbon ion (C+).

They found that in Orion, CH+ is emitting light instead of absorbing it, which means that it is warmer than the background gas. This was surprising to scientists because the CH+ molecule is incredibly reactive and needs a high amount of energy to form, so when it interacts with the background hydrogen in the cloud it gets destroyed.