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Category: chemistry – Page 148

New Research Sheds Light on Origins of Social Behaviors

Male fruit flies typically display antisocial behavior towards other males, preferring the company of females, which they identify through chemical receptors. However, recent studies by biologists at Cornell University indicate that the visual system of fruit flies plays a significant role in their social interactions.

This discovery provides new insights into the potential roots of varied social behaviors in humans, including those associated with conditions like bipolar disorder and autism.

The paper was recently published in Current Biology.

Scientists 3D print self-heating microfluidic devices

MIT researchers have used 3D printing to produce self-heating microfluidic devices, demonstrating a technique which could someday be used to rapidly create cheap, yet accurate, tools to detect a host of diseases.

Microfluidics, miniaturized machines that manipulate fluids and facilitate , can be used to detect disease in tiny samples of blood or fluids. At-home test kits for COVID-19, for example, incorporate a simple type of microfluidic.

But many microfluidic applications require chemical reactions that must be performed at specific temperatures. These more complex , which are typically manufactured in a , are outfitted with heating elements made from gold or platinum using a complicated and expensive fabrication process that is difficult to scale up.

The oldest stars in our galaxy make elements that aren’t yet on the periodic table

Move over uranium, the Milky Way’s oldest stars have bigger and better elements to make.

A group of researchers from across the United States, Canada and Sweden have discovered ancient neutron stars might have created elements with atomic mass greater than 260.

With an atomic mass of 238, uranium is the heaviest naturally occurring element known on Earth, though others like plutonium have been found in trace amounts due to reactions in uranium deposits.

Researchers safely integrate fragile 2D materials into devices, opening a path to unique electronic properties

Two-dimensional materials, which are only a few atoms thick, can exhibit some incredible properties, such as the ability to carry electric charge extremely efficiently, which could boost the performance of next-generation electronic devices.

However, integrating 2D materials into devices and systems like computer chips is notoriously difficult. These ultrathin structures can be damaged by conventional fabrication techniques, which often rely on the use of chemicals, high temperatures, or destructive processes like etching.

To overcome this challenge, researchers from MIT and elsewhere have developed a new technique to integrate 2D materials into devices in a single step while keeping the surfaces of the materials and the resulting interfaces pristine and free from defects.

New high school curriculum teaches color chemistry and AI simultaneously

North Carolina State University researchers have developed a weeklong high school curriculum that helps students quickly grasp concepts in both color chemistry and artificial intelligence—while sparking their curiosity about science and the world around them.

To test whether a short high school science module could effectively teach something about both chemistry—a notoriously thorny subject—and (AI), the researchers designed a relatively simple experiment involving pH levels, which reflect the acidity or alkalinity of a liquid solution.

When testing pH levels on a , color conversion charts provide a handy reference: more acidic solutions turn test strips red when a lot of acidity is present and turn test strips yellow and green as acid levels weaken. Test strips turn deep purple when liquids are highly alkaline and turn blue and dark green as alkaline levels decline.

Molecular Toxicology and Cancer Prevention

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Molecular toxicology is a field that investigates the interactions between chemical or biological molecules and organisms at the molecular level. In this Special Issue, we focus on the toxic effects and mechanisms of action of chemical and biological molecules, will be of great interest of readers in molecular toxicology and applied pharmacology.

Metamaterials and origamic metal-organic frameworks

Origami is a paper folding process usually associated with child’s play mostly to form a paper-folded crane, yet it is, as of recently a fascinating research topic. Origami-inspired materials can achieve mechanical properties that are difficult to achieve in conventional materials, and materials scientists are still exploring such constructs based on origami tessellation at the molecular level.

In a new report now published in Nature Communications, Eunji Jin and a research team in chemistry and particle acceleration at the Ulsan National Institute of Science and Technology, Republic of Korea, described the development of a two-dimensional porphyrinic -, self-assembled from zinc nodes and porphyrin linkers based on tessellation.

The team combined theory and experimental outcomes to demonstrate origami mechanisms underlying the 2D porphyrinic metal-organic framework with the flexible linker as a pivoting point. The 2D tessellation hidden within the 2D metal-organic framework unveiled origami molecules at the .

Ultra-thin metal-organic layers prevent ice crystal formation in novel cryoprotectants

Small amounts of nanometer-thin metal-organic layers efficiently protect red blood cells during freezing and thawing, as a team of researchers writing in the journal Angewandte Chemie International Edition has discovered. The nanolayers, made from metal-organic frameworks based on the metal hafnium, prevent ice crystal formation at very low concentrations. This effective novel cryoprotection mode could be used to develop new and more efficient cryoprotectants for the biosciences.

Cryoprotectants prevent ice crystals from forming when samples are frozen. Growing crystals can damage delicate cell membranes and cell components and disrupt cell integrity. Some solvents or polymers make good cryoprotectants; they keep ice in check by binding and disrupting their ordered assembly during ice formation.

Synthetic chemistry has yet more tricks up its sleeve for targeting and influencing ice formation in a more effective way. Metal-organic frameworks (MOFs) are three-dimensional crystalline networks of metal ions linked by organic ligands. These ligands can be tailored to bind such as water, allowing the assembly of the water molecules into ice crystals to be very precisely tuned.

How cell identity is preserved when cells divide

An MIT study suggests 3D folding of the genome is key to cells’ ability to store and pass on “memories” of which genes they should express.

Every cell in the human body contains the same genetic instructions, encoded in its DNA. However, out of about 30,000 genes, each cell expresses only those genes that it needs to become a nerve cell, immune cell, or any of the other hundreds of cell types in the body.

Each cell’s fate is largely determined by chemical modifications to the proteins that decorate its DNA; these modification in turn control which genes get turned on or off. When cells copy their DNA to divide, however, they lose half of these modifications, leaving the question: How do cells maintain the memory of what kind of cell they are supposed to be?

A new MIT study proposes a theoretical model that helps explain how these memories are passed from generation to generation when cells divide. The research team suggests that within each cell’s nucleus, the 3D folding of its genome determines which parts of the genome will be marked by these chemical modifications. After a cell copies its DNA, the marks are partially lost, but the 3D folding allows the cell to easily restore the chemical marks needed to maintain its identity. And each time a cell divides, chemical marks allow a cell to restore its 3D folding of its genome. This way, by juggling the memory between 3D folding and the marks, the memory can be preserved over hundreds of cell divisions.

Ultrahigh-gain organic transistors based on van der Waals metal-barrier interlayer-semiconductor junction

To achieve high intrinsic gain (Ai) in OTFTs, it is necessary to enlarge output resistance (ro) or transconductance (gm) according to a typical formula of Ai = gmro, which is very difficult for conventional OTFTs because of inherent device structure and operating mode limitations (11, 12). Recently, the “Schottky barrier” (SB) strategy based on metal-semiconductor junction (MS junction) has been adopted in TFTs to pursue high-gain and low-saturation voltage, including subthreshold SB-TFTs (11, 12, 15, 16) and source-gated transistors (17, 18). Unfortunately, the subthreshold transistors are limited in low and narrow subthreshold operating region rather than the normal ON-state region (namely, the normal voltage operating region in a typical TFT), which are difficult to be compatible with typical circuits. As far as we know, the ultrahigh-gain (1000) OTFTs operating in the ON-state region have not been previously reported. On the other hand, the state-of-the-art OTFTs above have mostly suffered from uncontrollable barriers owing to energy-level mismatches and a series of complex interface problems, such as Fermi-level pinning and interface chemical disorder (19). In this case, considerable low-energy carriers are allowed to pass through the junction by thermionic field emission and tunneling models instead of thermionic emission model, which is not conducive to obtaining a high output resistance and high intrinsic gain. Most barrier heights in MS junction do not conform to the prediction value of Schottky-Mott rule. Theoretically, an ideal and high-quality barrier with thermionic emission model allows the rapid depletion of carriers at the source electrode, thus yielding ultrahigh gain, infinite output resistance, and low saturation voltage (11, 12). In addition, infinite output resistance at the saturation regime indicates that the output current is very stable and flat. This performance is helpful because only a single OTFT is used as a simplified current stabilizer in circuits without complex circuit design, which benefits low power and low cost in circuits. Therefore, it is necessary to develop a high-quality barrier strategy to modulate charge injection to meet the requirements of ultrahigh-gain OTFTs.

Here, we demonstrate a metal-barrier interlayer-semiconductor (MBIS) junction to prepare high-performance MBIS-OTFT with an ultrahigh gain of ~104 in the ON-state region, low saturation voltage, almost negligible hysteresis, and good stability. On the basis of low-energy processes and in situ surface oxidation technology, the high-quality van der Waals MBIS junction with wide-bandgap semiconductor (mainly Ga2O3) interlayer is achieved, allowing for an adjustable barrier height and thermionic emission properties. A series of in situ experiments and simulations revealed the relationship between the barriers and the device’s performance. Furthermore, as demonstrations, a simplified current stabilizer and an ultrahigh-gain organic inverter are exhibited without complex circuit design.