Lifeboat Foundation

While people usually put a lot of effort into finding a partner, recent research suggests that our bodies are choosy in their own ways. Chemical signals that are released by human eggs can attract sperm, and new work has shown that eggs also use these molecules to ‘select’ the sperm they want. The findings, reported in Proceedings of the Royal Society B, showed that eggs also don’t always pick the same sperm; eggs from different women can opt for sperm from different men.

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Rational design of compounds with specific properties requires understanding and fast evaluation of molecular properties throughout chemical compound space — the huge set of all potentially stable molecules. Recent advances in combining quantum-mechanical calculations with machine learning provide powerful tools for exploring wide swathes of chemical compound space. We present our perspective on this exciting and quickly developing field by discussing key advances in the development and applications of quantum-mechanics-based machine-learning methods to diverse compounds and properties, and outlining the challenges ahead. We argue that significant progress in the exploration and understanding of chemical compound space can be made through a systematic combination of rigorous physical theories, comprehensive synthetic data sets of microscopic and macroscopic properties, and modern machine-learning methods that account for physical and chemical knowledge.

An Oregon State University environmental engineering professor has solved a decades-old mystery regarding the behavior of fluids, a field of study with widespread medical, industrial, and environmental applications.

The research by Brian D. Wood, published in the Journal of Fluid Mechanics, clears a roadblock that has been puzzling scientific minds for nearly 70 years and paves the way to a clearer picture of how chemicals mix in fluids.

A more complete grasp of that basic principle provides a foundation for advances in a range of areas – from how pollutants spread in the atmosphere to how drugs perfuse tissues within the human body.

Every second of every day, countless biochemical reactions take place in our bodies’ cells. The organization of this complex system is the result of billions of years of evolution, fine-tuning our functions since the first primordial organisms.

One such vital reaction is “methylation,” where a methyl group —a carbon atom linked to three hydrogen atoms—attaches itself to a target molecule. Methylation is involved in the regulation of everything from DNA to proteins, and it is so vital that it can be found in all living organisms.

In a recent paper published in Communications Biology, a team of researchers lead by Jean-Michel Fustin and Hitoshi Okamura from Kyoto University’s Graduate School of Pharmaceutical Sciences has uncovered an intimate connection between methylation and the body’s circadian rhythms: a link that exists even in organisms that don’t traditionally “sleep,” such as bacteria.

“And by answering the question, how do psychedelics work, we also inadvertently shine a light on other questions science has shied away from for decades. How do our brains generate our sense of self? What is the neurochemistry of consciousness?”

New research asks, how does psilocybin create a feeling of ego dissolution, and what chemicals in the brain create our subjective sense of self?

Analysing data from hundreds of major earthquakes, Doyeon Kim at the University of Maryland and his colleagues have found a new structure beneath the volcanic Marquesas Islands in the South Pacific Ocean. The structure, known as an ultra-low velocity (ULV) zone, is about 1000 kilometres in diameter and 25 kilometres thick, says Kim.

These structures are called ULV zones because seismic waves pass through them at slower velocities, but what they are made of is still a mystery. They might be chemically distinct from Earth’s iron–nickel alloy core and silicate rock mantle, or have different thermal properties.

The researchers discovered the structure while analysing 7000 records of seismic activity from earthquakes that occurred around the Pacific Ocean basin between 1990 and 2018. The earthquakes all had a magnitude of 6.5 or greater, and were all deeper than 200 kilometres below Earth’s surface.

A memristor¹ has been proposed as an artificial synapse for emerging neuromorphic computing applications^2,3. To train a neural network in memristor arrays, changes in weight values in the form of device conductance should be distinct and uniform³. An electrochemical metallization (ECM) memory^4,5, typically based on silicon (Si), has demonstrated a good analogue switching capability^6,7 owing to the high mobility of metal ions in the Si switching medium⁸. However, the large stochasticity of the ion movement results in switching variability. Here we demonstrate a Si memristor with alloyed conduction channels that shows a stable and controllable device operation, which enables the large-scale implementation of crossbar arrays. The conduction channel is formed by conventional silver (Ag) as a primary mobile metal alloyed with silicidable copper (Cu) that stabilizes switching. In an optimal alloying ratio, Cu effectively regulates the Ag movement, which contributes to a substantial improvement in the spatial/temporal switching uniformity, a stable data retention over a large conductance range and a substantially enhanced programmed symmetry in analogue conductance states. This alloyed memristor allows the fabrication of large-scale crossbar arrays that feature a high device yield and accurate analogue programming capability. Thus, our discovery of an alloyed memristor is a key step paving the way beyond von Neumann computing.

A simple chemical reaction gives platelets the ability to swim around.

Numerous efforts have been made to improve the temporal resolution of CRISPR-Cas9–mediated DNA cleavage to the hour time scale. Liu et al. developed a Cas9 system that achieved genome-editing manipulation at the second time scale (see the Perspective by Medhi and Jasin). Part of the guide RNA is chemically caged, allowing the Cas9-guide RNA complex to bind at a specific genomic locus without cleavage until activation by light. This fast CRISPR system achieves genome editing at high temporal resolution, enabling the study of early molecular events of DNA repair processes. This system also has high spatial resolution at short time scales, allowing editing of one genomic allele while leaving the other unperturbed.

Science, this issue p. 1265; see also p. 1180

CRISPR-Cas systems provide versatile tools for programmable genome editing. Here, we developed a caged RNA strategy that allows Cas9 to bind DNA but not cleave until light-induced activation. This approach, referred to as very fast CRISPR (vfCRISPR), creates double-strand breaks (DSBs) at the submicrometer and second scales. Synchronized cleavage improved kinetic analysis of DNA repair, revealing that cells respond to Cas9-induced DSBs within minutes and can retain MRE11 after DNA ligation. Phosphorylation of H2AX after DNA damage propagated more than 100 kilobases per minute, reaching up to 30 megabases. Using single-cell fluorescence imaging, we characterized multiple cycles of 53BP1 repair foci formation and dissolution, with the first cycle taking longer than subsequent cycles and its duration modulated by inhibition of repair. Imaging-guided subcellular Cas9 activation further facilitated genomic manipulation with single-allele resolution.