Tuning of Oxygen Vacancies in CoO Electrocatalyst for Effectiveness in Urea Oxidation and Water Splitting.

The development of an excellent multifunctional electrocatalyst that is based on non-precious metal is critical for improving the electrochemical processes of the hydrogen evolution reaction (HER), the oxygen evolution reaction (OER), and the urea oxidation reaction (UOR) in alkaline media. This study demonstrates that incorporating Mo into CoO facilitated the formation of rich oxygen vacancies (Vo), which promotes effective nitrate adsorption and activation in urea electrolysis. Subsequently, in situ/operando X-ray absorption spectroscopy is used to explore the active sites in Mo-CoO-3 under OER, indicating the oxygen vacancies are first filled with OH in Mo-CoO; facilitated the pre-oxidation of low-valence Co, and promoted the reconstruction/deprotonation of intermediate Co-OOH.

Bimetallic nanoalloys planted on super-hydrophilic carbon nanocages featuring tip-intensified hydrogen evolution electrocatalysis.

The insufficient availability and activity of interfacial water remain a major challenge for alkaline hydrogen evolution reaction (HER). Here, we propose an "on-site disruption and near-site compensation" strategy to reform the interfacial water hydrogen bonding network via deliberate cation penetration and catalyst support engineering. This concept is validated using tip-like bimetallic RuNi nanoalloys planted on super-hydrophilic and high-curvature carbon nanocages (RuNi/NC).

Determining the reusability of Tenax beads (60-80 mesh) in estimates of bioaccessibility using single-point extractions.

Single-point Tenax extractions are a viable means of estimating bioaccessibility of hydrophobic organic contaminants in sediment, soil, and intestinal fluids. One advantage of this extraction technique is that after thorough cleaning and drying, Tenax beads can be reused in subsequent extractions with the assumption that no changes in bioaccessibility estimates will occur. This assumption of reusability, however, has not been tested.

Presence of Delocalized Ti 3d Electrons in Ultrathin Single-Crystal SrTiO.

Strontium titanate (STO), with a wide spectrum of emergent properties such as ferroelectricity and superconductivity, has received significant attention in the community of strongly correlated materials. In the strain-free STO film grown on the SrRuO buffer layer, the existing polar nanoregions can facilitate room-temperature ferroelectricity when the STO film thickness approaches 10 nm. Here we show that around this thickness scale, the freestanding STO films without the influence of a substrate show the tetragonal structure at room temperature, contrasting with the cubic structure seen in bulk form.

Realization of Electron Antidoping by Modulating the Breathing Distortion in BaBiO.

The recent proposal of antidoping scheme breaks new ground in conceiving conversely functional materials and devices; yet, the few available examples belong to the correlated electron systems. Here, we demonstrate both theoretically and experimentally that the main group oxide BaBiO is a model system for antidoping using oxygen vacancies. The first-principles calculations show that the band gap systematically increases due to the strongly enhanced Bi-O breathing distortions away from the vacancies and the annihilation of Bi 6/O 2 hybridized conduction bands near the vacancies.

Spectroscopic characterization of electronic structures of ultra-thin single crystal LaSrMnO.

We have successfully fabricated high quality single crystalline LaSrMnO (LSMO) film in the freestanding form that can be transferred onto silicon wafer and copper mesh support. Using soft x-ray absorption (XAS) and resonant inelastic x-ray scattering (RIXS) spectroscopy in transmission and reflection geometries, we demonstrate that the x-ray emission from Mn 3s-2p core-to-core transition (3sPFY) seen in the RIXS maps can represent the bulk-like absorption signal with minimal self-absorption effect around the Mn L-edge. Similar measurements were also performed on a reference LSMO film grown on the SrTiO substrate and the agreement between measurements substantiates the claim that the bulk electronic structures can be preserved even after the freestanding treatment process.

Disparate Exciton-Phonon Couplings for Zone-Center and Boundary Phonons in Solid-State Graphite.

The exciton-phonon coupling in highly oriented pyrolytic graphite is studied using resonant inelastic x-ray scattering (RIXS) spectroscopy. With ∼70  meV energy resolution, multiple low energy excitations associated with coupling to phonons can be clearly resolved in the RIXS spectra. Using resonance dependence and the closed form for RIXS cross section without considering the intermediate state mixing of phonon modes, the dimensionless coupling constant g is determined to be 5 and 0.

The key energy scales of Gd-based metallofullerene determined by resonant inelastic x-ray scattering spectroscopy.

Endohedral metallofullerenes, formed by encaging Gd inside fullerenes like C, can exhibit enhanced proton relaxitivities compared with other Gd-chelates, making them the promising contrast agents for magnetic resonance imaging (MRI). However, the underlying key energy scales of Gd Sc N@C (x  =  1-3) remain unclear. Here, we carry out resonant inelastic x-ray scattering (RIXS) experiments on Gd Sc N@C at Gd N -edges to directly study the electronic structure and spin flip excitations of Gd 4f electrons.

Modular soft x-ray spectrometer for applications in energy sciences and quantum materials.

Over the past decade, the advances in grating-based soft X-ray spectrometers have revolutionized the soft X-ray spectroscopies in materials research. However, these novel spectrometers are mostly dedicated designs, which cannot be easily adopted for applications with diverging demands. Here we present a versatile spectrometer design concept based on the Hettrick-Underwood optical scheme that uses modular mechanical components.

Reproducibly creating hierarchical 3D carbon to study the effect of Si surface functionalization on the oxygen reduction reaction.

We report a new method to reproducibly fabricate functional 3D carbon structures directly on a current collector, e.g. stainless steel.

Observation of the origin of d0 magnetism in ZnO nanostructures using X-ray-based microscopic and spectroscopic techniques.

Efforts have been made to elucidate the origin of d(0) magnetism in ZnO nanocactuses (NCs) and nanowires (NWs) using X-ray-based microscopic and spectroscopic techniques. The photoluminescence and O K-edge and Zn L3,2-edge X-ray-excited optical luminescence spectra showed that ZnO NCs contain more defects than NWs do and that in ZnO NCs, more defects are present at the O sites than at the Zn sites. Specifically, the results of O K-edge scanning transmission X-ray microscopy (STXM) and the corresponding X-ray-absorption near-edge structure (XANES) spectroscopy demonstrated that the impurity (non-stoichiometric) region in ZnO NCs contains a greater defect population than the thick region.

Genome mining of the biosynthetic gene cluster of the polyene macrolide antibiotic tetramycin and characterization of a P450 monooxygenase involved in the hydroxylation of the tetramycin B polyol segment.

A polyene macrolide antibiotic tetramycin biosynthetic gene cluster was identified by genome mining and isolated from Streptomyces hygrospinosus var. beijingensis. Genetic and in silico analyses gave insights into the mechanism of biosynthesis of tetramycin, and a model of the tetramycin biosynthetic pathway is proposed.

Elucidation of Piericidin A1 biosynthetic locus revealed a thioesterase-dependent mechanism of α-pyridone ring formation.

Piericidins are a class of α-pyridone antibiotics that inhibit mitochondrial respiratory chain and exhibit antimicrobial, antifungal, and antitumor activities. Sequential analysis of Streptomyces piomogeues var. Hangzhouwanensis genome revealed six modular polyketide synthases, an amidotransferase, two methyltransferases, and a monooxygenase for piericidin A1 production.

Expansion of the known Klebsiella pneumoniae species gene pool by characterization of novel alien DNA islands integrated into tmRNA gene sites.

Klebsiella pneumoniae is an important bacterial pathogen of man that is commonly associated with opportunistic and hospital-associated infections. Increasing levels of multiple-antibiotic resistance associated with this species pose a major emerging clinical problem. This organism also occurs naturally in other diverse environments, including the soil.

TADB: a web-based resource for Type 2 toxin-antitoxin loci in bacteria and archaea.

TADB (http://bioinfo-mml.sjtu.edu.

mGenomeSubtractor: a web-based tool for parallel in silico subtractive hybridization analysis of multiple bacterial genomes.

mGenomeSubtractor performs an mpiBLAST-based comparison of reference bacterial genomes against multiple user-selected genomes for investigation of strain variable accessory regions. With parallel computing architecture, mGenomeSubtractor is able to run rapid BLAST searches of the segmented reference genome against multiple subject genomes at the DNA or amino acid level within a minute. In addition to comparison of protein coding sequences, the highly flexible sliding window-based genome fragmentation approach offered can be used to identify short unique sequences within or between genes.

dndDB: a database focused on phosphorothioation of the DNA backbone.

Background: The Dnd DNA degradation phenotype was first observed during electrophoresis of genomic DNA from Streptomyces lividans more than 20 years ago. It was subsequently shown to be governed by the five-gene dnd cluster. Similar gene clusters have now been found to be widespread among many other distantly related bacteria.