Archive for the ‘chemistry’ category: Page 5

Sep 1, 2019

Astronomers capture rare cosmic collision that’s a chance to ‘understand the chemistry of the universe’

Posted by in categories: chemistry, cosmology

It’s a cosmic collision that has astronomers rethinking one of the universe’s most colossal events: the collision of massive stars.

In a new paper published in the journal Monthly Notices of the Royal Astronomical Society, astronomers reveal the finding of a kilonova produced by the collision of two massive stellar objects called neutron stars. The collision is roughly 1,000 times brighter than the death of a massive star called a supernova. And they say it produced several hundred planets’ worth of gold and platinum.

But astronomers almost missed it.

Aug 26, 2019

Drugs that target cell metabolism may lead to new treatment for childhood brain cancer

Posted by in categories: biotech/medical, chemistry, genetics, neuroscience

Scientists have identified a class of drugs that may have potential to treat a rare and deadly form of brain cancer that affects young children.

The research team, led by Ranjit Bindra, MD, PhD, and colleagues at the Yale Cancer Center, also included co-senior authors Charles Brenner, PhD, professor and DEO of biochemistry at the University of Iowa Carver College of Medicine, and Michael E. Berens, PhD, from the Translational Genomics Research Institute in Phoenix.

The findings, published Aug. 22 in Nature Communications, focus on Diffuse Intrinsic Pontine Glioma (DIPG), a rare, incurable cancer that affects the brainstem in children under age 10. Previous work had identified mutations in a gene called PPM1D as a cause of this cancer.

Aug 23, 2019

Is There an Element Zero?

Posted by in categories: chemistry, particle physics

The periodic table contains a wide array of elements, numbered from one (hydrogen) to 118 (oganesson), with each number representing the number of protons stored within an atom’s nucleus. Scientists are constantly working to create new elements by cramming more and more protons into nuclei, expanding the periodic table. The effort sparks curiosity and questions: Can the table be enlarged in the opposite direction? Is it possible to make an element zero? Does it already exist?

“Element zero” has been a matter of conjecture for nearly a century, and no scientist searched more ardently for it than German chemist Andreas von Antropoff. It was Antropoff who placed the theoretical element atop a periodic table of his own devising, and it was also he who thought up a prescient name for it: neutronium.

You don’t widely hear Antropoff’’s name today, as his Nazi leanings earned the scientist international disgrace. You do, however, hear about neutronium. Today, the term commonly refers to a gaseous substance composed almost purely of neutrons, found within the tiniest, densest stars known to exist: neutron stars.

Aug 22, 2019

Self-assembled membrane with water-continuous transport pathways for precise nanofiltration

Posted by in categories: biotech/medical, chemistry, engineering, food, nanotechnology, sustainability

Self-assembled materials are attractive for next-generation materials, but their potential to assemble at the nanoscale and form nanostructures (cylinders, lamellae etc.) remains challenging. In a recent report, Xundu Feng and colleagues at the interdisciplinary departments of chemical and environmental engineering, biomolecular engineering, chemistry and the center for advanced low-dimension materials in the U.S., France, Japan and China, proposed and demonstrated a new approach to prevent the existing challenges. In the study, they explored size-selective transport in the water-continuous medium of a nanostructured polymer template formed using a self-assembled lyotropic H1 (hexagonal cylindrical shaped) mesophase (a state of matter between liquid and solid). They optimized the mesophase composition to facilitate high-fidelity retention of the H1 structure on photoinduced crosslinking.

The resulting nanostructured polymer material was mechanically robust with internally and externally crosslinked nanofibrils surrounded by a continuous aqueous medium. The research team fabricated a with size selectivity at the 1 to 2 nm length scale and water permeabilities of ~10 liters m−2 hour−1 bar−1 μm. The membranes displayed excellent anti-microbial properties for practical use. The results are now published on Science Advances and represent a breakthrough for the potential use of self-assembled membrane-based nanofiltration in practical applications of water purification.

Membrane separation for filtration is widely used in diverse technical applications, including seawater desalination, gas separation, food processing, fuel cells and the emerging fields of sustainable power generation and distillation. During nanofiltration, dissolved or suspended solutes ranging from 1 to 10 nm in size can be removed. New nanofiltration membranes are of particular interest for low-cost treatment of wastewaters to remove organic contaminants including pesticides and metabolites of pharmaceutical drugs. State-of-the-art membranes presently suffer from a trade-off between permeability and selectivity where increased permeability can result in decreased selectivity and vice-versa. Since the trade-off originated from the intrinsic structural limits of conventional membranes, materials scientists have incorporated self-assembled materials as an attractive solution to realize highly selective separation without compromising permeability.

Aug 21, 2019

Rapid tissue regeneration induced by intracellular ATP delivery—A preliminary mechanistic study

Posted by in categories: biotech/medical, chemistry

Circa 2017

We have reported a new phenomenon in acute wound healing following the use of intracellular ATP delivery—extremely rapid tissue regeneration, which starts less than 24 h after surgery, and is accompanied by massive macrophage trafficking, in situ proliferation, and direct collagen production. This unusual process bypasses the formation of the traditional provisional extracellular matrix and significantly shortens the wound healing process. Although macrophages/monocytes are known to play a critical role in the initiation and progression of wound healing, their in situ proliferation and direct collagen production in wound healing have never been reported previously. We have explored these two very specific pathways during wound healing, while excluding confounding factors in the in vivo environment by analyzing wound samples and performing in vitro studies. The use of immunohistochemical studies enabled the detection of in situ macrophage proliferation in ATP-vesicle treated wounds. Primary human macrophages and Raw 264.7 cells were used for an in vitro study involving treatment with ATP vesicles, free Mg-ATP alone, lipid vesicles alone, Regranex, or culture medium. Collagen type 1α 1, MCP-1, IL-6, and IL-10 levels were determined by ELISA of the culture supernatant. The intracellular collagen type 1α1 localization was determined with immunocytochemistry. ATP-vesicle treated wounds showed high immunoreactivity towards BrdU and PCNA antigens, indicating in situ proliferation. Most of the cultured macrophages treated with ATP-vesicles maintained their classic phenotype and expressed high levels of collagen type 1α1 for a longer duration than was observed with cells treated with Regranex. These studies provide the first clear evidence of in situ macrophage proliferation and direct collagen production during wound healing. These findings provide part of the explanation for the extremely rapid tissue regeneration, and this treatment may hold promise for acute and chronic wound care.

Wound healing is a complex and dynamic process involving the replacement of devitalized and missing structures. The traditional view of wound healing is that it involves hemostasis, inflammation, proliferation, and remodeling, and these steps result in a lag of 3–6 d before reepithelialization starts [1,2]. We have discovered that the intracellular delivery of adenosine triphosphate using ATP-vesicles as an acute wound treatment enhances wound healing [3,4]. The most unprecedented finding was that new tissue started to generate within 24 h, and it continued to grow to eliminate the wound cavity quickly [4–6]. This growth was attained by early and massive monocyte/macrophage trafficking, proliferation, and fast collagen production for direct formation of extracellular matrix (ECM).

Aug 21, 2019

Scientists find a way to create long-life, fast-charging batteries

Posted by in categories: chemistry, energy, physics, transportation

A group of researchers led by Skoltech Professor Pavel Troshin studied coordination polymers, a class of compounds with scarcely explored applications in metal-ion batteries, and demonstrated their possible future use in energy storage devices with a high charging/discharging rate and stability. The results of their study were published in the journal Chemistry of Materials.

The charging/discharging rate is one of the key characteristics of lithium-ion batteries. Most modern commercial batteries need at least an hour to get fully charged, which certainly limits the scope of their application, in particular, for electric vehicles. The trouble with active materials, such as the most popular anode material, graphite, is that their capacity decays significantly, as their charging rate increases. To retain the battery capacity at high charging rates, the active electrode materials must have high electronic and ionic conductivity, which is the case with the newly-discovered coordination polymers that are derived from and salts of , such as nickel or copper. Although these compounds hold a great promise, their application in lithium-ion batteries remains virtually unexplored.

A recent study undertaken by a group of scientists from Skoltech and the Institute for Problems of Chemical Physics of RAS led by Professor P. Troshin in collaboration with the University of Cologne (Germany) and the Ural Federal University, focused on tetraaminobenzene-based linear polymers of nickel and copper. Although the linear polymers exhibited much lower initial electronic conductivity as compared to their two-dimensional counterparts, it transpired that they can be used as anode materials that get charged/discharged in less than a minute, because their conductivity increases dramatically after the first discharge due to lithium doping.

Aug 10, 2019

New study in Science: Why humans in Africa fled to the mountains during the last ice age

Posted by in categories: biotech/medical, chemistry, science

People in Ethiopia did not live in low valleys during the last ice age. Instead they lived high up in the inhospitable Bale Mountains. There they had enough water, built tools out of obsidian and relied mainly on giant rodents for nourishment. This discovery was made by an international team of researchers led by Martin Luther University Halle-Wittenberg (MLU) in cooperation with the Universities of Cologne, Bern, Marburg, Addis Ababa and Rostock. In the current issue of “Science”, the researchers provide the first evidence that our African ancestors had already settled in the mountains during the Palaeolithic period, about 45,000 years ago.

At around 4,000 metres above sea level, the Bale Mountains in southern Ethiopia are a rather inhospitable region. There is a low level of oxygen in the air, temperatures fluctuate sharply, and it rains a lot. “Because of these adverse living conditions, it was previously assumed that humans settled in the Afro-Alpine region only very lately and for short periods of time,” says Professor Bruno Glaser, an expert in soil biogeochemistry at MLU. Together with an international team of archaeologists, soil scientists, palaeoecologists, and biologists, he has been able to show that this assumption is incorrect. People had already begun living for long periods of time on the ice-free plateaus of the Bale Mountains about 45,000 years ago during the Middle Pleistocene Epoch. By then the lower valleys were already too dry for survival.

For several years, the research team investigated a rocky outcrop near the settlement of Fincha Habera in the Bale Mountains in southern Ethiopia. During their field campaigns, the scientists found a number of stone artefacts, clay fragments and a glass bead. “We also extracted information from the soil as part of our subproject,” says Glaser. Based on the sediment deposits in the soil, the researchers from Halle were able to carry out extensive biomarker and nutrient analyses as well as radiocarbon dating and thus draw conclusions as to how many people lived in the region and when they lived there. For this work, the scientists also developed a new type of palaeothermometer which could be used to roughly track the weather in the region — including temperature, humidity and precipitation. Such analyses can only be done in natural areas with little contamination, otherwise the soil profile will have changed too much by more recent influences.

Aug 7, 2019

Physicists measure how electrons in transition metals get redistributed within fraction of optical oscillation cycle

Posted by in categories: chemistry, computing, particle physics

Researchers in the Department of Physics of ETH Zurich have measured how electrons in so-called transition metals get redistributed within a fraction of an optical oscillation cycle. They observed the electrons getting concentrated around the metal atoms within less than a femtosecond. This regrouping might influence important macroscopic properties of these compounds, such as electrical conductivity, magnetization or optical characteristics. The work therefore suggests a route to controlling these properties on extremely fast time scales.

The distribution of electrons in , which represent a large part of the periodic table of chemical elements, is responsible for many of their interesting properties used in applications. The magnetic properties of some of the members of this group of materials are, for example, exploited for data storage, whereas others exhibit excellent electrical conductivity. Transition metals also have a decisive role for novel materials with more exotic behaviour that results from strong interactions between the electrons. Such materials are promising candidates for a wide range of future applications.

In their experiment, whose results they report in a paper published today in Nature Physics, Mikhail Volkov and colleagues in the Ultrafast Laser Physics group of Prof. Ursula Keller exposed thin foils of the transition metals titanium and zirconium to short laser pulses. They observed the redistribution of the electrons by recording the resulting changes in optical properties of the metals in the extreme ultraviolet (XUV) domain. In order to be able to follow the induced changes with sufficient temporal resolution, XUV pulses with a duration of only few hundred attoseconds (10-18 s) were employed in the measurement. By comparing the experimental results with theoretical models, developed by the group of Prof. Angel Rubio at the Max Planck Institute for the Structure and Dynamics of Matter in Hamburg, the researchers established that the change unfolding in less than a femtosecond (10-15 s) is due to a modification of the electron localization in the vicinity of the metal atoms.

Aug 4, 2019

Antibiotic found in ocean could help beat superbugs

Posted by in categories: biotech/medical, chemistry, military

In the deep of the ocean, where the sun’s rays struggle to penetrate, organisms lurk that could solve the biggest medical crisis facing humanity.

Far below the surface bacteria are engaged in warfare with each other — and to do so they make an antibiotic so strong it can destroy the toughest superbugs in our hospitals.

“But there’s a problem,” Rebecca Goss, a professor of organic chemistry at the University of St Andrews, said. “It disintegrates in sunlight.”

Jul 30, 2019

Dr. Deborah Mash, Professor of Neurology and Molecular and Cellular Pharmacology, Director of the Brain Endowment Bank at the University of Miami, and CEO of DemeRx — Ira Pastor — ideaXme Show

Posted by in categories: aging, biotech/medical, business, chemistry, genetics, health, life extension, neuroscience, science, transhumanism
Page 5 of 35First23456789Last