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Archive for the ‘chemistry’ category: Page 91

Dec 7, 2022

Bacterial extracellular electron transfer: a powerful route to the green biosynthesis of inorganic nanomaterials for multifunctional applications

Posted by in categories: biotech/medical, chemistry, health, nanotechnology

Two categories of nanofabrication technologies are known as top-down and bottom-up approaches [5]. For the former, nanosized materials are prepared through the rupture of bulk materials to fine particles, and such a process is usually conducted by diverse physical and mechanical techniques like lithography, laser ablation, sputtering, ball milling and arc-discharging [6, 7]. These techniques themselves are simple, and nanosized materials can be produced quickly after relatively short technological process, but expensive specialized equipment and high energy consumption are usually inevitable. Meanwhile, a variety of efficient chemical bottom-up methods, where atoms assemble into nuclei and then form nanoparticles, have been intensively studied to synthesize and modulate nanomaterials with specific shape and size [8].

Indeed, chemical methodologies, including but not limited to, aqueous reaction using chemical reducing agents (e.g. hydrazine hydrate and sodium borohydride), electrochemical deposition, hydrothermal/solvothermal synthesis, sol–gel processing, chemical liquid/vapor deposition, have been developed up to now [5, 6]. These approaches can not only produce diverse nanomaterials with fairly high yields, but also endow fine controllability in tailoring nanostructures and properties of the products. Nevertheless, they have been encountering some serious challenges of harsh reaction conditions (e.g. pH and temperature), potential risks in human health and environment, and low cost-effectiveness. Moreover, there are biosafety concerns on products synthesized chemically using hazardous reagents, which restricts their applications in many areas, particularly in medicines and pharmaceuticals [9].

Impressively, biological methodology is becoming a favourite in nanomaterial synthesis nowadays to address challenges in chemical synthesis. Compared to chemical routes, biosynthesis using natural and biological materials as reducing, stabilizing and capping agents are simple, energy-and cost-effective, mild and environment-friendly, which is termed as “Green Chemistry” [2, 6]. More significantly, the biologically synthesized nanomaterials have much better competitiveness in biocompatibility, compared to those chemically derived counterparts. On the one hand, the biogenic nanomaterials are free from toxic contamination of by-products that are usually involved in chemical synthesis process; on the other hand, the biosynthesis do not need additional stabilizing agents because either the used organisms themselves or their constituents can act as capping and stabilizing agents and the attached biological components in turn form biocompatible envelopes on the resultant nanomaterials, leading to actively interact with biological systems [2]. As one of the most abundant biological resources, some microorganisms have adapted to habitat contaminated with toxic metals, and thus evolved powerful tactics for remediating polluted environment while recycling metal resources [7, 10], and some review articles on the biosynthesis of MNPs using diverse microorganisms including bacteria, yeast, fungi, alga, etc. and their applications have been published in recent years [1, 2, 6, 7, 10].

Dec 6, 2022

X-rays reveal elusive chemistry for better electric vehicle batteries

Posted by in categories: chemistry, energy, nanotechnology, sustainability, transportation

Researchers around the world are on a mission to relieve a bottleneck in the clean energy revolution: batteries. From electric vehicles to renewable grid-scale energy storage, batteries are at the heart of society’s most crucial green innovations—but they need to pack more energy to make these technologies widespread and practical.

Now, a team of scientists led by chemists at the U.S. Department of Energy’s (DOE) Brookhaven National Laboratory and Pacific Northwest National Laboratory (PNNL) has unraveled the complex chemical mechanisms of a component that is crucial for boosting energy density: the interphase. Their work published today in Nature Nanotechnology.

Dec 3, 2022

UV and black light tattoos: Everything you need to know

Posted by in categories: chemistry, health

UV tattoos use a fluorescent dye, which means the tattoo only appears under UV light. There is little evidence on whether UV tattoos are safe for human skin.

UV tattoos, also known as black light tattoos, are invisible under regular lighting and only appear under UV light due to the fluorescent compounds within the ink.

There is no regulation over UV tattoos, so there may be some potential health risks, depending on the ink’s chemicals. UV tattoos will also require similar aftercare to regular tattoos.

Dec 3, 2022

Brain mapping in mice may explain why pain makes us lose our appetite

Posted by in categories: chemistry, food, mapping, neuroscience

Examinations using microscopes confirmed that these neurons were active in the mice with chronic pain. When the researchers used chemicals to stop the neuronal activity in this cortex, the mice’s appetites improved.

Similarly, when the researchers used chemicals to activate these neurons in mice that weren’t in pain, the animals ate less, even if they had been deprived of food before the experiment.

This is the first time that researchers have traced the brain mechanisms behind pain-related appetite loss, the researchers wrote.

Dec 3, 2022

Mom’s Dietary Fat Rewires Male and Female Brains Differently

Posted by in categories: chemistry, health, neuroscience, sex

Excess fat triggers immune cells to overeat serotonin in the brain of developing male mice, leading to depression-like behavior. More than half of all women in the United States are overweight or obese when they become pregnant. While being or becoming overweight during pregnancy can have potential health risks for moms, there are also hints that it may tip the scales for their kids to develop psychiatric disorders like autism or depression, which often affects one gender more than the other.

What hasn’t been understood however is how the accumulation of fat tissue in mom might signal through the placenta in a sex-specific way and rearrange the developing offspring’s brain.

To fill this gap, Duke postdoctoral researcher Alexis Ceasrine, Ph.D., and her team in the lab of Duke psychology & neuroscience professor Staci Bilbo, Ph.D., studied pregnant mice on a high-fat diet. In findings appearing November 28 in the journal Nature Metabolism, they found that mom’s high-fat diet triggers immune cells in the developing brains of male but not female mouse pups to overconsume the mood-influencing brain chemical serotonin, leading to depressed-like behavior.

Dec 2, 2022

Shocking decline in human sperm counts

Posted by in category: chemistry

A study in the journal Human Reproduction finds that human sperm counts fell by 62% in the last 50 years, possibly a result of poor diets and a toxic soup of forever chemicals in air and water.

Dec 2, 2022

New process allows 3D printing of microscale metallic parts

Posted by in categories: 3D printing, chemistry

Engineers at Caltech have developed a method for 3D printing pure and multicomponent metals, at a resolution that is, in some cases, an order of magnitude smaller than previously possible. The process, which uses water-based chemistry and 3D printing, was described in a paper published in Nature on October 20.

Dec 1, 2022

Femtosecond to attosecond light pulses from a molecular modulator

Posted by in category: chemistry

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Ultrafast science has begun to tackle the measurement of electronic and chemical processes taking place on the few-femtosecond-to-attosecond timescale. This field requires high-power, extremely short-duration laser pulses. Here we review progress towards the generation of such pulses by Raman scattering in a medium whose component molecules oscillate in phase, which modulates the optical polarizability of the medium and generates high-order Raman sidebands on a field propagating through it. This process may occur with high efficiency and thus lead to sufficient bandwidth for supporting few-femtosecond to attosecond pulses. Significant progress has recently been made in the use of this technique to deliver useable ultrashort pulses in the visible to ultraviolet regions of the spectrum.

Dec 1, 2022

Nanotech strategy shows promise for treating autoimmune disease

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

Scientists at Scripps Research have reported success in initial tests of a new, nanotech-based strategy against autoimmune diseases.

The scientists, who reported their results in ACS Nano, engineered cell-like “” that target only the driving an autoimmune reaction, leaving the rest of the immune system intact and healthy. The nanoparticles greatly delayed, and in some animals even prevented, in a mouse model of arthritis.

“The potential advantage of this approach is that it would enable safe, long-term treatment for where the immune system attacks its own tissues or organs—using a method that won’t cause broad immune suppression, as current treatments do,” says study senior author James Paulson, Ph.D., Cecil H. and Ida M. Green Chair of Chemistry in the Department of Molecular Medicine at Scripps Research.

Dec 1, 2022

Scientists link rare genetic phenomenon to neuron function, schizophrenia

Posted by in categories: biotech/medical, chemistry, genetics, robotics/AI

In our cells, the language of DNA is written, making each of us unique. A tandem repeat occurs in DNA when a pattern of one or more nucleotides—the basic structural unit of DNA coded in the base of chemicals cytosine ©, adenine (A), guanine (G) and thymine (T)—is repeated multiple times in tandem. An example might be: CAG CAG CAG, in which the pattern CAG is repeated three times.

Now, using state-of-the-art whole-genome sequencing and machine learning techniques, the UNC School of Medicine lab of Jin Szatkiewicz, Ph.D., associate professor of genetics, and colleagues conducted one of the first and the largest investigations of repeats in , elucidating their contribution to the development of this devastating disease.

Published in the journal Molecular Psychiatry, the research shows that individuals with schizophrenia had a significantly higher rate of rare tandem repeats in their genomes—7% more than individuals without schizophrenia. And they observed that the tandem repeats were not randomly located throughout the genome; they were primarily found in genes crucial to brain function and known to be important in schizophrenia, according to previous studies.

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