Lifeboat Foundation

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 metal-organic framework, self-assembled from zinc nodes and porphyrin linkers based on origami 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 molecular level.

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 crystal formation in check by binding water molecules 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 small molecules such as water, allowing the assembly of the water molecules into ice crystals to be very precisely tuned.

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?

Continue reading “How cell identity is preserved when cells divide” »

To achieve high intrinsic gain (A_i) in OTFTs, it is necessary to enlarge output resistance (r_o) or transconductance (g_m) according to a typical formula of A_i = g_mr_o, 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.

Per-and polyfluoroalkyl substances (PFAS), manufactured chemicals used in products such as food packaging and cosmetics, can lead to reproductive problems, increased cancer risk and other health issues. A growing body of research has also linked the chemicals to lower bone mineral density, which can lead to osteoporosis and other bone diseases. But most of those studies have focused on older, non-Hispanic white participants and only collected data at a single point in time.

Now, researchers from the Keck School of Medicine of USC have replicated those results in a longitudinal study of two groups of young participants, primarily Hispanics, a group that faces a heightened risk of bone disease in adulthood.

“This is a population completely understudied in this area of research, despite having an increased risk for bone disease and osteoporosis,” said Vaia Lida Chatzi, MD, Ph.D., a professor of population and public health sciences at the Keck School of Medicine and the study’s senior author.

One of nature’s most common organic materials—lignin—can be used to create stable and environmentally friendly organic solar cells. Researchers at Linköping University and the Royal Institute of Technology (KTH) have now shown that untreated kraft lignin can be used to make solar cells even more environmentally friendly and reliable. The study has been published in the journal Advanced Materials.

Sunlight currently seems to be one of the main sustainable energy sources. Traditional solar cells made from silicon are efficient but have an energy-demanding and complicated manufacturing process that may lead to hazardous chemical spills. Organic solar cells have therefore become a hot research area thanks to their low production cost, light weight and flexibility, and hence have many applications, such as indoor use or attached to clothing to power personal electronic devices.

But one problem is that organic solar cells are made of plastic, or polymers derived from oil. So, although organic, they are not as environmentally friendly as they could be.

Aging | doi:10.18632/aging.204896. Jae-Hyun Yang, Christopher A. Petty, Thomas Dixon-McDougall, Maria Vina Lopez, Alexander Tyshkovskiy, Sun Maybury-Lewis, Xiao Tian, Nabilah Ibrahim, Zhili Chen, Patrick T. Griffin, Matthew Arnold, Jien Li, Oswaldo A. Martinez, Alexander Behn, Ryan Rogers-Hammond, Suzanne Angeli, Vadim N. Gladyshev, David A. Sinclair.

Could a fecal transplant pill be the antidepressants of the future?

Depression is real, and it is complex. Most conditions that affect our brain chemistry are going to be complex, and there are no easy, simple answers. We can’t cure depression by just exercising more, eating better, or taking a short vacation to recharge (although there is some evidence that getting more money, especially to lift you out of poverty, helps relieve depressive symptoms).

Micrometeorites, tiny space rocks, may have helped deliver nitrogen, a vital life ingredient, to Earth during our solar system’s early days. This finding was published in Nature Astronomy on November 30 by an international research team, including scientists from the University of Hawaiʻi at Mānoa and Kyoto University. They discovered that nitrogen compounds like ammonium salts are common in material from regions distant from the sun. However, how these compounds reached Earth’s orbit was unclear.

The study suggests that more nitrogen compounds were transported near Earth than previously thought. These compounds could have contributed to life on our planet. The research was based on material collected from the asteroid Ryugu by Japan’s Hayabusa2 spacecraft in 2020. Ryugu, a small sun-orbiting rocky object, is carbon-rich and has experienced considerable space weathering due to micrometeorite impacts and solar charged ions.

The scientists studied the Ryugu samples to understand the materials reaching Earth’s orbit. They used an electron microscope and found the Ryugu samples’ surface covered with tiny iron and nitrogen minerals. They theorized that micrometeorites carrying ammonia compounds collided with Ryugu. This collision sparked chemical reactions on magnetite, resulting in iron nitride formation.