Browse Articles

Unintended consequences of well-intended interventions

Haldane’s law works through X:Autosome incompatibility in Caenorhabditis briggsae/C. nigoni hybrids

An AI-based algorithm for analyzing physical activity and health-related fitness in youth

Abstract In recent years, with the country’s emphasis on national fitness, the health status of primary and secondary school students has become the focus of social attention. As one of the important means to measure students’ physical fitness, physical examination results are closely related to students’ physical fitness. However, there are some problems in the traditional physical examination management, such as subjective influence, complicated manual calculation, and difficulty in retaining and making full use of data. Based on the physical fitness test data of primary schools in the past five years from 2018 to 2022, this study aims to apply machine learning and deep learning methods to deeply analyze and mine data information, provide automatic classification methods and accurate performance prediction models, and then expand to provide students with personalized training suggestions to assist teachers in making reasonable teaching plans and other applications. The first research method is the classification method based on BP neural network, which realizes automatic comprehensive grade classification and achieves 98.448% classification performance, and explores students’ physical health and grade classification. The second research method is the performance prediction model based on CNN-LSTM neural network, which combines CNN feature matrix and LSTM continuous time series information to provide more accurate performance prediction for various physical test items, and provides a new method for the management and evaluation of physical test results of primary and secondary school students through data analysis and prediction model. These methods not only solve the problems of traditional evaluation methods, but also provide scientific guidance for schools and promote the healthy development of students and the optimization of physical education.

Can paleontologists pinpoint the dawn of the dinosaurs?

On-device cryogenic quenching enables robust amorphous tellurium for threshold switching

CRFusion: a novel LiDAR-camera fusion network for BEV map construction

Charting a course for the National Academies and the nation we serve

Global solidarity in genomic surveillance improves early detection of acute respiratory virus threats

Comparative analysis of machine learning models with SHAP interpretation for causes of highway flood-damage blocking

Hydroxo-bridged active site of flavodiiron NO reductase revealed by NRVS and DFT

The use of oxygen and nitrate as terminal electron acceptors provides organisms with a huge amount of available energy but necessitates methods to detoxify reactive intermediates. The mechanisms of NO and O 2 detoxification in many organisms involve flavodiiron proteins (FDPs). Although the proteinaceous ligands that coordinate the diiron active site of these enzymes are well established, its exact coordination environment remains under debate due to conflicting interpretations of crystallographic and spectroscopic/theoretical studies. Using 57 Fe nuclear resonance vibrational spectroscopy (NRVS), complemented by Mössbauer spectroscopy and density functional theory, we elucidated the redox-linked structural changes in the FDP from Escherichia coli . The as-isolated diferric state is best described as a dihydroxo-bridged Fe(III)–(μOH − ) 2 –Fe(III) core, which upon reduction converts to a monohydroxo Fe(II)–(μOH − )–Fe(II) center through the loss of one bridging ligand. This ligand rearrangement defines the structural basis for redox-linked reactivity in FDPs. The study further demonstrates that photoreduction of a stable metalloprotein species can occur under NRVS conditions, indicating that synchrotron-based vibrational measurements may induce subtle redox changes even under low photon flux. These findings provide a mechanistic framework for interpreting redox-linked ligand dynamics in diiron enzymes and highlight the need to collect damage-free X-ray crystal structures avoiding potential beam-induced reduction. Furthermore, diiron active sites are found in numerous other enzyme classes (e.g., methane monooxygenase), and therefore, our findings have implications way beyond the FDPs.

A global assessment of coastal vulnerability and dominant contributors

Comparison of multi-stress resilience in wild and domesticated Cowpea

<i>Chlamydomonas</i> chloroplast genes tolerate compression of the genetic code to just 51 codons

Genome scale engineering has enabled codon compression of the universal genetic code to eliminate seven codons in Escherichia coli , but to allow more radical schemes for codon compression and reassignment to be tested at genome scale, while avoiding significant technical challenges, smaller, simpler genetic systems are needed. Here, we report a recoding scheme for the 205 kb Chlamydomonas reinhardtii chloroplast genome, in which two stop codons and one or more of the codons for arginine, glycine, isoleucine, leucine, and serine, all of which have two cognate transfer RNAs (tRNAs), are absent, compressing the genetic code to 51 codons. Several recoding strategies were tested on the essential rpoA gene, encoding a subunit of the chloroplast RNA polymerase. A defined compression scheme, which relied on swapping the target codons with the permitted frequent codons, could replace the native sequence without affecting expression of a reporter protein or strain fitness under standard laboratory conditions. The same strategy was successfully used for codon compression of ycf1 , encoding a subunit of the chloroplast translocon, psaA and psbA , intron-containing highly expressed genes encoding reaction center subunits of both photosystems, and an 8.5 kb operon encoding essential and nonessential genes. Finally, we tested degeneracy of the 51-codon genetic code by exploring the combinatorial design for the large subunit of Rubisco, relying on restoration of photosynthesis in an rbcL mutant strain. More than 70 functional sequences with diverse codons were recovered. For all recoded genes, viable homoplasmic lines were obtained, showing the efficacy of our codon compression scheme.

Evidence for Alfvén waves powering auroral arc via a static electric potential drop

Abstract Natural light displays known as the aurora provide a captivating glimpse into the electromagnetic dynamics in space plasmas. Aurorae are not exclusive to Earth but also observed on celestial bodies including planets and even comets. Previous studies have unveiled two fundamental auroral acceleration mechanisms: electric potential and Alfvénic acceleration. However, the relation of the energy processes associated with the auroral acceleration region has remained unclear mainly due to the lack of quantitative analysis. Employing quantitative assessment of energy budget using multi-platforms from the magnetosphere to auroral ionosphere, our findings underscore the interplay between these two mechanisms. Here we show that energy carried by Alfvén waves travels from the magnetosphere to the auroral acceleration region, forming an electric potential drop that accelerates particles to produce aurorae. Similarities in auroral particle behaviors between Earth and Jupiter suggest the applicability of the terrestrial scenario to Jupiter and potentially other celestial bodies in the Universe.

Influence of endogenous estrogen exposure on the development of hypertension in a cohort study using multistate model analysis

Biopsy-resolved cryo-EM structures of amyloid fibrils provide molecular insights into AL amyloidosis

Systemic light chain amyloidosis (AL) is characterized by amyloid fibril deposition in multiple organs, often severely affecting cardiac function. In this study, we extracted amyloid fibrils directly from abdominal fat and cardiac tissue biopsies obtained from three AL patients. Using cryo-electron microscopy, we determined five distinct structures of light chain (LC) amyloid fibrils. Our results demonstrate that LC fibrils from different patients adopt unique structural conformations, highlighting patient-specific fibril variations. Conversely, LC fibrils extracted from different tissues within the same patient share highly similar overall fibril structures, yet exhibit localized conformational variations, potentially shaped by distinct environmental cofactors. This study emphasizes the combined roles of patient-specific protein sequences and tissue-specific microenvironments in defining LC fibril conformation. The determination of LC fibril structures directly from easily accessible abdominal fat biopsy provides critical molecular insights into AL amyloidosis pathology, facilitating the development of therapeutic strategies.

Affiliative behaviours regulate allostasis development and shape biobehavioural trajectories in horses

Abstract Social interactions shape both the physiological and behavioural development of offspring, and poor care/early caregiver loss is known to promote adverse outcomes during infancy in both animals and humans. How affiliative behaviours impact the future development of offspring remains an open question. Here, we used Equus caballus (domestic horse) as a model to investigate this question. By coupling magnetic resonance imaging, longitudinal biobehavioural assessments and advanced multivariate statistical modelling, we found that prolonged maternal presence during infancy promotes the maturation of brain regions involved in both social behaviour (anterior cingulate cortex and retrosplenial cortex) and physiological regulation (hypothalamus and amygdala). Additionally, offspring benefiting from a prolonged maternal presence showed higher default mode network connectivity, improved social competences and feeding behaviours, and higher concentrations of circulating lipids (triglyceride and cholesterol). The findings of the present study underscore the salient role of social interactions in the development of allostatic regulation in offspring.

Automated characterization of the gray matter white matter distribution demonstrates age-related decline

Immature <i>Caenorhabditis elegans</i> motor neurons control early embryo behavior via both synaptic and nonsynaptic GABA release

Prenatal brain activity has long lasting effects on subsequent neurodevelopment. It is unclear if early brain activity is dominated by cell intrinsic, synaptic, or nonsynaptic mechanisms. We address this question by analyzing Caenorhabditis elegans embryo behavior in snf-11 mutants, which lack a plasma membrane GABA reuptake pump (orthologous to GAT1). At 510 to 570 min postfertilization, embryo motion was transiently and potently inhibited in snf-11 GAT1 mutants, which precedes formation of most nerve ring synapses. This transient motion inhibition requires GABA synthesis in DD motor neurons and UNC-49 GABA A receptors in body muscles. When motion inhibition occurs, DD neurons have not yet completed neurite outgrowth. Genetic analysis suggests that motion inhibition was mediated by both synaptic and tonic GABA release from DD motor neurons. These results suggest that DD neurons control embryo behavior prior to completing their developmental maturation.

K48-ubiquitin-dependent proteases cut-up post-ER proteins