Integrating PtCo Intermetallic with Highly Graphitized Carbon Toward Durable Oxygen Electroreduction in Proton Exchange Membrane Fuel Cells.

Exploiting robust and high-efficiency electrocatalysts for sluggish oxygen reduction reaction (ORR) is essential for proton exchange membrane fuel cells (PEMFCs) toward long-term operation for practical applications, yet remains challenging. Herein, the ordered PtCo intermetallic is reported with a Pt-rich shell loaded on a highly graphitized carbon carrier (O-PtCo@GCoNC) prepared by an impregnation annealing strategy. Systematic X-ray spectroscopic, operando electrochemical techniques and theoretical calculations reveal that thanks to the synergistic interaction of the core-shell PtCo intermetallic structure with a tailor-made Pt electronic configuration and highly graphitized carbon, O-PtCo@GCoNC exhibits significantly enhanced activity and stability toward ORR.

Linkage Microenvironment and Oxygen Electroreduction Reaction Performance Correlationship of Iron Phthalocyanine-based Polymers.

Iron phthalocyanine-based conjugated polymers (PFePc) offer well-defined sites, rendering them ideal model systems to elucidate structure-property relationships towards oxygen reduction reaction (ORR), but have struggled to achieve improved catalytic activity due to uniform electron distribution of iron center and difficulty in molecular-level structure design. Although rationally linkage microenvironmental regulation is an effective approach to adjusting activity, the underlying fundamental mechanism is incompletely understood. Herein, systematic DFT calculations and experimental investigation of PFePc analogous reveal that the incorporation of the electron-withdrawing benzophenone linkage into the PFePc backbone (PFePc-3) drives the delocalization of Fe d-orbital electrons, downshifts the d-band energy level, thereby tailoring the key OH* intermediate interaction, demonstrating enhanced ORR performance with a half-wave potential of 0.

High-Density Accessible Iron Single-Atom Catalyst for Durable and Temperature-Adaptive Laminated Zinc-Air Batteries.

Designing single-atom catalysts (SACs) with high density of accessible sites by improving metal loading and sites utilization is a promising strategy to boost the catalytic activity, but remains challenging. Herein, a high site density (SD) iron SAC (D-Fe-N/C) with 11.8 wt.

Carbon Nanocage with Maximum Utilization of Atomically Dispersed Iron as Efficient Oxygen Electroreduction Nanoreactor.

As key parameters of electrocatalysts, the density and utilization of active sites determine the electrocatalytic performance toward oxygen reduction reaction. Unfortunately, prevalent oxygen electrocatalysts fail to maximize the utilization of active sites due to inappropriate nanostructural design. Herein, a nano-emulsion induced polymerization self-assembly strategy is employed to prepare hierarchical meso-/microporous N/S co-doped carbon nanocage with atomically dispersed FeN (denoted as Meso/Micro-FeNSC).

Longitudinal study of stool-associated microbial taxa in sibling pairs with and without autism spectrum disorder.

Autism Spectrum Disorder (ASD) is a complex neurodevelopmental disorder influenced by both genetic and environmental factors. Recently, gut dysbiosis has emerged as a powerful contributor to ASD symptoms. In this study, we recruited over 100 age-matched sibling pairs (between 2 and 8 years old) where one had an Autism ASD diagnosis and the other was developing typically (TD) (432 samples total).

A Comparative Evaluation of Tools to Predict Metabolite Profiles From Microbiome Sequencing Data.

Metabolomic analyses of human gut microbiome samples can unveil the metabolic potential of host tissues and the numerous microorganisms they support, concurrently. As such, metabolomic information bears immense potential to improve disease diagnosis and therapeutic drug discovery. Unfortunately, as cohort sizes increase, comprehensive metabolomic profiling becomes costly and logistically difficult to perform at a large scale.

A sliding-bulge structure at the Dicer processing site of pre-miRNAs regulates alternative Dicer processing to generate 5'-isomiRs.

5'-isomiRs expand the repertoire of miRNA targets. However, how they are generated is not well understood. Previously, we showed that for some miRNAs in mammalian cells, Drosha cleaves at multiple sites to generate multiple pre-miRNAs that give rise to multiple 5'-isomiRs.

A CRISPR-Based Screen Identifies Genes Essential for West-Nile-Virus-Induced Cell Death.

West Nile virus (WNV) causes an acute neurological infection attended by massive neuronal cell death. However, the mechanism(s) behind the virus-induced cell death is poorly understood. Using a library containing 77,406 sgRNAs targeting 20,121 genes, we performed a genome-wide screen followed by a second screen with a sub-library.

Distinct expression profiles of stress defense and DNA repair genes in Daphnia pulex exposed to cadmium, zinc, and quantum dots.

The ever-increasing production and use of nanocrystaline semiconductors (Quantum dots; QDs) will inevitably result in increased appearance of these nanomaterials in the aquatic environment. However, the behavior and potential toxicity of heavy metal constituted nanoparticulates in aquatic invertebrates is largely unknown, especially with regard to molecular responses. The freshwater crustacean Daphnia pulex is a well-suited toxicological and ecological model to study molecular responses to environmental stressors.

RNA-seq analysis to identify novel roles of scleraxis during embryonic mouse heart valve remodeling.

Heart valve disease affects up to 30% of the population and has been shown to have origins during embryonic development. Valvulogenesis begins with formation of endocardial cushions in the atrioventricular canal and outflow tract regions. Subsequently, endocardial cushions remodel, elongate and progressively form mature valve structures composed of a highly organized connective tissue that provides the necessary biomechanical function throughout life.

Pol III Promoters to Express Small RNAs: Delineation of Transcription Initiation.

Pol III promoters such as U6 are commonly used to express small RNAs, including small interfering RNA, short hairpin RNA, and guide RNA, for the clustered regularly interspaced short palindromic repeats genome-editing system. However, whether the small RNAs were precisely expressed as desired has not been studied. Here, using deep sequencing to analyze small RNAs, we show that, for mouse U6 promoter, sequences immediately upstream of the putative initiation site, which is often modified to accommodate the restriction enzyme sites that enable easy cloning of small RNAs, are critical for precise transcription initiation.

Lower and upper stem-single-stranded RNA junctions together determine the Drosha cleavage site.

Microprocessor [Drosha-DGCR8 (DiGeorge syndrome critical region gene 8) complex] processing of primary microRNA (pri-miRNA) is the critical first step in miRNA biogenesis, but how the Drosha cleavage site is determined has been unclear. Previous models proposed that the Drosha-DGCR8 complex measures either ~22 nt from the upper stem-single-stranded RNA (ssRNA, terminal loop) junction or ~11 nt from the lower stem-ssRNA junction to determine the cleavage site. Here, using miRNA-offset RNAs to determine the Drosha cleavage site, we show that the Microprocessor measures the distances from both the lower and upper stem-ssRNA junctions to determine the cleavage site in human cells, and optimal distances from both structures are critical to the precision of Drosha processing.

Emergence of genotype I of Japanese encephalitis virus as the dominant genotype in Asia.

Japanese encephalitis virus (JEV), a mosquito-borne zoonotic pathogen, is one of the major causes of viral encephalitis worldwide. Previous phylogenetic studies based on the envelope protein indicated that there are four genotypes, and surveillance data suggest that genotype I is gradually replacing genotype III as the dominant strain. Here we report an evolutionary analysis based on 98 full-length genome sequences of JEV, including 67 new samples isolated from humans, pigs, mosquitoes, midges.

MiRPara: a SVM-based software tool for prediction of most probable microRNA coding regions in genome scale sequences.

Background: MicroRNAs are a family of ~22 nt small RNAs that can regulate gene expression at the post-transcriptional level. Identification of these molecules and their targets can aid understanding of regulatory processes. Recently, HTS has become a common identification method but there are two major limitations associated with the technique.