Science (20240503 publishing) one-week paper introduction

Compile | Li Yan

Science, 3 MAY 2024, Volume 384 Issue 6695

Science, May 3, 2024, Vol. 384, No. 6695

Chemistry

An active, stable cubic molybdenum carbide catalyst for the high-temperature reverse water-gas shift reaction

An active and stable cubic molybdenum carbide catalyst for high-temperature reverse water-gas shift reaction

▲ 作者：MILAD AHMADI KHOSHOOEI, XIJUN WANG et al.

▲ Links:

https://www.science.org/doi/10.1126/science.adl1260

▲ Abstract:

Our study demonstrates that nanocrystalline cubic molybdenum carbide (α-Mo2C), prepared by a simple and scalable pathway, has 100% selectivity for CO2 reduction to CO while maintaining initial equilibrium conversion after exposure to harsh reaction conditions of 600 degrees for more than 500 hours.

The combination of in-situ and post-mortem characterization of the catalyst showed that its high activity, selectivity and stability were attributed to crystal phase purity, weak CO-Mo2C interaction and interstitial oxygen atoms, respectively. Mechanistic studies and density functional theory (DFT) calculations proved that the reaction was carried out by an H2-assisted redox mechanism.

▲ Abstract：

We show that nanocrystalline cubic molybdenum carbide (α-Mo2C), prepared through a facile and scalable route, offers 100% selectivity for CO2 reduction to CO while maintaining its initial equilibrium conversion at high space velocity after more than 500 hours of exposure to harsh reaction conditions at 600°C. The combination of operando and postreaction characterization of the catalyst revealed that its high activity, selectivity, and stability are attributable to crystallographic phase purity, weak CO-Mo2C interactions, and interstitial oxygen atoms, respectively. Mechanistic studies and density functional theory (DFT) calculations provided evidence that the reaction proceeds through an H2-aided redox mechanism.

Physics

Atomic physics on a 50-nm scale: Realization of a bilayer system of dipolar atoms

Atomic physics at the 50 nm scale: Realization of a dipole atomic bilayer system

▲ 作者：LI DU, PIERRE BARRAL et al.

▲ Links:

https://www.science.org/doi/10.1126/science.adh3023

▲ Abstract:

In this study, we implemented a super-resolution technique that can locate and arrange atoms on a scale of less than 50 nanometers without any fundamental resolution limitations.

This technique was validated by the creation of a bilayer of dysprosium atoms and the observation of dipole interactions between two physically separated layers through interlayer sympathetic cooling and coupled collective excitation.

At the 50 nm scale, the dipole interaction is 1,000 times stronger than at 500 nm. For two atoms in the optical tweezers, this should enable a pure magnetic dipole gate with kilohertz velocity.

▲ Abstract：

In this work, we implemented a super-resolution technique that localizes and arranges atoms on a sub–50-nm scale, without any fundamental limit in resolution. We demonstrate this technique by creating a bilayer of dysprosium atoms and observing dipolar interactions between two physically separated layers through interlayer sympathetic cooling and coupled collective excitations. At 50-nm distance, dipolar interactions are 1000 times stronger than at 500 nm. For two atoms in optical tweezers, this should enable purely magnetic dipolar gates with kilohertz speed.

N-type semiconducting hydrogel

N-type semiconductor hydrogels

▲ 作者：PEIYUN LI, WENXI SUN et al.

▲ Links:

https://www.science.org/doi/10.1126/science.adj4397

▲ Abstract:

We have developed single- and multi-network hydrogels based on water-soluble N-type semiconducting polymers to impart semiconductor properties to traditional hydrogels. These hydrogels have good electron mobility and a high on/off ratio, enabling the fabrication of complementary logic circuits and signal amplifiers with low power consumption and high gain.

We demonstrated that hydrogel electronic components with good bioadhesive and compatible interfaces can sense and amplify electrophysiological signals and improve the signal-to-noise ratio.

▲ Abstract：

We developed single- and multiple-network hydrogels based on a water-soluble n-type semiconducting polymer, endowing conventional hydrogels with semiconducting capabilities. These hydrogels show good electron mobilities and high on/off ratios, enabling the fabrication of complementary logic circuits and signal amplifiers with low power consumption and high gains. We demonstrate that hydrogel electronics with good bioadhesive and biocompatible interface can sense and amplify electrophysiological signals with enhanced signal-to-noise ratios.

Medicine

Risk of meningomyelocele mediated by the common 22q11.2 deletion

Common 22q11.2 deletion results in a risk of meningomeningocele

▲ 作者：KENG IOI VONG, SANGMOON LEE et al.

▲ Links:

https://www.science.org/doi/10.1126/science.adl1624

▲ Abstract:

Meningomyelocele is one of the most severe forms of neural tube defects (NTDs) and the most common structural birth defect of the central nervous system. We joined forces with the Spina Bifida Sequencing Consortium to determine the cause.

By sequencing the exome and genome of 715 pairs of parent-offspring triplets, we identified six patients with chromosome 22q11.2 deletion, suggesting a 23-fold increased risk compared to the general population. In addition, analysis of another 22q11.2 deletion sequence showed a 12- to 15-fold increased risk of NTD for meningomeningocele.

Deletion of Crkl is sufficient to replicate NTDs in mice, where both penetrance and expression are exacerbated by maternal folate deficiency. Thus, common 22q11.2 deletion increases the risk of meningomeningocele, which can be partially mitigated by folic acid supplementation.

▲ Abstract：

Meningomyelocele is one of the most severe forms of neural tube defects (NTDs) and the most frequent structural birth defect of the central nervous system. We assembled the Spina Bifida Sequencing Consortium to identify causes. Exome and genome sequencing of 715 parent-offspring trios identified six patients with chromosomal 22q11.2 deletions, suggesting a 23-fold increased risk compared with the general population. Furthermore, analysis of a separate 22q11.2 deletion cohort suggested a 12- to 15-fold increased NTD risk of meningomyelocele. The loss of Crkl, one of several neural tube–expressed genes within the minimal deletion interval, was sufficient to replicate NTDs in mice, where both penetrance and expressivity were exacerbated by maternal folate deficiency. Thus, the common 22q11.2 deletion confers substantial meningomyelocele risk, which is partially alleviated by folate supplementation.

网络科学Network Science

Induction of social contagion for diverse outcomes in structured experiments in isolated villages

Social contagion induction with different outcomes in isolated village structure experiments

▲ 作者：EDOARDO M. AIROLDI AND NICHOLAS A. CHRISTAKIS

▲ Links:

https://www.science.org/doi/10.1126/science.adi5147

▲ Abstract:

Some people occupy topological positions in social networks, which enhances their effectiveness in inducing spillover effects. We built a face-to-face network of 24,702 people in 176 isolated villages in Honduras and randomly assigned villages according to different methods, changing the proportion of households that received the 22-month health education method and the method of selecting families (random assignment and "acquaintance recommendation" method).

We assessed 117 different knowledge, attitudes and practice outcomes. The "acquaintance referral" method reduces the number of households required to reach a certain level throughout the village. Knowledge spreads more easily than behavior, and spillover effects extend to varying degrees. The more accessible results also show greater spillovers. The social network established on the basis of "acquaintance recommendation" has effectively promoted the improvement of the welfare of the whole population through social contagion.

▲ Abstract：

Certain people occupy topological positions within social networks that enhance their effectiveness at inducing spillovers. We mapped face-to-face networks among 24,702 people in 176 isolated villages in Honduras and randomly assigned villages to targeting methods, varying the fraction of households receiving a 22-month health education package and the method by which households were chosen (randomly versus using the friendship-nomination algorithm). We assessed 117 diverse knowledge, attitude, and practice outcomes. Friendship-nomination targeting reduced the number of households needed to attain specified levels of village-wide uptake. Knowledge spread more readily than behavior, and spillovers extended to two degrees of separation. Outcomes that were intrinsically easier to adopt also manifested greater spillovers. Network targeting using friendship nomination effectively promotes population-wide improvements in welfare through social contagion.

大气科学Atmospheric Sciences

Locally narrow droplet size distributions are ubiquitous in stratocumulus clouds

Partially narrow droplet size distribution is prevalent in Stratocumulus

▲ 作者：NITHIN ALLWAYIN, MICHAEL L. LARSEN et al.

▲ Links:

https://www.science.org/doi/10.1126/science.adi5550

▲ Abstract:

Currently, global climate models (GCMs) parameterize the droplet size distribution in clouds as a broad cloud-averaged gamma. Using a digital holographic measurement of the volume of discrete stratocumulus clouds, we found that the droplet size distribution in the cloud is narrower on the centimeter scale, which is completely different from the average of the clouds.

These local distributions tend to form "pockets" of more similar cloud regions, each characterized by the size distribution shape being diluted to varying degrees. These observations open the way for new modeling characterization of microphysical processes.

▲ Abstract：

Current global climate models (GCMs) parameterize cloud droplet size distributions as broad, cloud-averaged gammas. Using digital holographic measurements of discrete stratocumulus cloud volumes, we found cloud droplet size distributions to be narrower at the centimeter scale, never resembling the cloud average. These local distributions tended to form pockets of similar-looking cloud regions, each characterized by a size distribution shape that is diluted to varying degrees. These observations open the way for new modeling representations of microphysical processes.