Pentagon-Rich Caged Carbon Catalyst for the Oxygen Reduction Reaction in Acidic Electrolytes.

The interaction between electron spin and oxygen molecules in non-platinum catalysts, particularly carbon catalysts, significantly influences the catalytic performance of the oxygen reduction reaction (ORR). A promising approach to developing high-performance catalysts involves introducing five-membered ring structures with spin into graphitic carbons. In this study, we present the successful synthesis of cage-like cubic carbon catalysts enriched with pentagon structures using pentagon ring-containing C and a NaCl template.

Atomic Force Microscopy Imaging and Analysis of Prokaryotic Genome Organization.

This protocol describes the application of atomic force microscopy for structural analysis of prokaryotic and organellar nucleoids. It is based on a simple cell manipulation procedure that enables stepwise dissection of the nucleoid. The procedure includes (i) on-substrate lysis of cells and (ii) enzyme treatment, followed by atomic force microscopy.

Theoretical framework for mixed-potential-driven catalysis.

Mixed-potential-driven catalysis is expected to be a distinctive heterogeneous catalytic reaction that produces products different from those produced by thermal catalytic reactions without the application of external energy. Electrochemically, the mechanism is similar to that of corrosion. However, a theory that incorporates catalytic activity as a parameter has not been established.

The effectiveness of Japanese public funding to generate emerging topics in life science and medicine.

Understanding the effectiveness of public funds to generate emerging topics will assist policy makers in promoting innovation. In the present study, we aim to clarify the effectiveness of grants to generate emerging topics in life sciences and medicine since 1991 with regard to Japanese researcher productivity and grants from the Japan Society for the Promotion of Science. To clarify how large grant amounts and which categories are more effective in generating emerging topics from both the PI and investment perspectives, we analyzed awarded PI publications containing emerging keywords (EKs; the elements of emerging topics) before and after funding.

Rhombohedral Boron Monosulfide as a p-Type Semiconductor.

Two-dimensional materials have wide ranging applications in electronic devices and catalysts owing to their unique properties. Boron-based compounds, which exhibit a polymorphic nature, are an attractive choice for developing boron-based two-dimensional materials. Among them, rhombohedral boron monosulfide (r-BS) has recently attracted considerable attention owing to its unique layered structure similar to that of transition metal dichalcogenides and a layer-dependent bandgap.

Critical impacts of interfacial water on C-H activation in photocatalytic methane conversion.

On-site and on-demand photocatalytic methane conversion under ambient conditions is one of the urgent global challenges for the sustainable use of ubiquitous methane resources. However, the lack of microscopic knowledge on its reaction mechanism prevents the development of engineering strategies for methane photocatalysis. Combining real-time mass spectrometry and operando infrared absorption spectroscopy with ab initio molecular dynamics simulations, here we report key molecular-level insights into photocatalytic green utilization of methane.

Chemisorption of CO on Nitrogen-Doped Graphitic Carbons.

The adsorption of CO on nitrogen-doped graphitic carbon materials, such as graphene nanosheet (GNS) powder and highly oriented pyrolytic graphite (HOPG), was comparatively studied using temperature-programmed desorption (TPD) and X-ray photoelectron spectroscopy (XPS). Desorption of CO was observed at approximately 380 K for both pyridinic-nitrogen (pyri-N)-doped GNS and pyri-N-doped HOPG samples in the TPD experiments, whereas no CO desorption was observed for graphitic nitrogen-doped HOPG. This indicated that only pyri-N species create identical CO adsorption sites on any graphitic carbon surface.

Activating Nitrogen-doped Graphene Oxygen Reduction Electrocatalysts in Acidic Electrolytes using Hydrophobic Cavities and Proton-conductive Particles.

Although pyridinic-nitrogen (pyri-N) doped graphene is highly active for the oxygen reduction reaction (ORR) of fuel cells in alkaline media, the activity critically decreases under acidic conditions. We report on how to prevent the deactivation based on the mechanistic understanding that governs the ORR kinetics. First, we considered that the deactivation is due to the hydration of pyri-NH , leading to a lower shift of the redox potential.

Hollow Spherical Fullerene Obtained by Kinetically Controlled Liquid-Liquid Interfacial Precipitation.

Nanomaterials with hollow structures are expected to exhibit new functionalities for materials engineering. Here we report the fabrication of fullerene (C ) spheres having different hollow structures by using a kinetically controlled liquid-liquid interfacial precipitation (KC-LLIP) method. For this purpose, 1,2-ethylenediamine (EDA) was used as a covalent cross-linker of C molecules to form C -EDA shells, while in-situ generated EDA-sulfur (EDA-S) droplets were applied as 'yolks' being eliminated by washing following formation of the yolk-shell structure, leading to hollow structures.

Hydrogenation of Formate Species Using Atomic Hydrogen on a Cu(111) Model Catalyst.

The reaction mechanism of the CHOH synthesis by the hydrogenation of CO on Cu catalysts is unclear because of the challenge in experimentally detecting reaction intermediates formed by the hydrogenation of adsorbed formate (HCOO). Thus, the objective of this study is to clarify the reaction mechanism of the CHOH synthesis by establishing the kinetic natures of intermediates formed by the hydrogenation of adsorbed HCOO on Cu(111). We exposed HCOO on Cu(111) to atomic hydrogen at low temperatures of 200-250 K and observed the species using infrared reflection absorption (IRA) spectroscopy and temperature-programmed desorption (TPD) studies.

Versatile nanoarchitectonics of Pt with morphology control of oxygen reduction reaction catalysts.

Electro-catalytic activity of Pt in the oxygen reduction reaction (ORR) depends strongly on its morphology. For an understanding of how morphology affects the catalytic properties of Pt, the investigation of Pt materials having well-defined morphologies is required. However, the challenges remain in rational and facile synthesis of Pt particles with tuneable well-defined morphology.

Single-Molecule/Cell Analyses Reveal Principles of Genome-Folding Mechanisms in the Three Domains of Life.

Comparative structural/molecular biology by single-molecule analyses combined with single-cell dissection, mass spectroscopy, and biochemical reconstitution have been powerful tools for elucidating the mechanisms underlying genome DNA folding. All genomes in the three domains of life undergo stepwise folding from DNA to 30-40 nm fibers. Major protein players are histone (Eukarya and Archaea), Alba (Archaea), and HU (Bacteria) for fundamental structural units of the genome.

Focusing and spin polarization of atomic hydrogen beam.

We have developed a spin-polarized-hydrogen beam with a hexapole magnet. By combining the beam chopper and pulsed laser ionization detection, the time-of-flight of the hydrogen beam was measured, and the dependence of the beam profile on the velocity was acquired, which was consistent with the beam trajectory simulations. The spin polarization of the beam was analyzed by using the Stern-Gerlach-type magnet in combination with the spatial scan of the detection laser.

Role of Pyridinic Nitrogen in the Mechanism of the Oxygen Reduction Reaction on Carbon Electrocatalysts.

The introduction of pyridinic nitrogen (pyri-N) into carbon-based electrocatalysts for the oxygen reduction reaction is considered to create new active sites. Herein, the role of pyri-N in such catalysts was investigated from a mechanistic viewpoint using carbon black (CB)-supported pyri-N-containing molecules as model catalysts; the highest activity was observed for 1,10-phenanthroline/CB. X-ray photoemission spectroscopy showed that in acidic electrolytes, both pyri-N atoms of 1,10-phenanthroline could be protonated to form pyridinium ions (pyri-NH ).

Different Proteins Mediate Step-Wise Chromosome Architectures in and .

Archaeal species encode a variety of distinct lineage-specific chromosomal proteins. We have previously shown that in , histone, Alba, and TrmBL2 play distinct roles in chromosome organization. Although our understanding of individual archaeal chromosomal proteins has been advancing, how archaeal chromosomes are folded into higher-order structures and how they are regulated are largely unknown.

Dynamical Quantum Filtering via Enhanced Scattering of para-H on the Orientationally Anisotropic Potential of SrTiO(001).

Quantum dynamics calculation, performed on top of density functional theory (DFT)-based total energy calculations, show dynamical quantum filtering via enhanced scattering of para-H on SrTiO(001). We attribute this to the strongly orientation-dependent (electrostatic) interaction potential between the H (induced) quadrupole moment and the surface electric field gradient of ionic SrTiO(001). These results suggest that ionic surfaces could function as a scattering/filtering media to realize rotationally state-resolved H.

What Happens in the Staphylococcal Nucleoid under Oxidative Stress?

The evolutionary success of as an opportunistic human pathogen is largely attributed to its prominent abilities to cope with a variety of stresses and host bactericidal factors. Reactive oxygen species are important weapons in the host arsenal that inactivate phagocytosed pathogens, but can survive in phagosomes and escape from phagocytic cells to establish infections. Molecular genetic analyses combined with atomic force microscopy have revealed that the MrgA protein (part of the Dps family of proteins) is induced specifically in response to oxidative stress and converts the nucleoid from the fibrous to the clogged state.

Active Sites and Mechanism of Oxygen Reduction Reaction Electrocatalysis on Nitrogen-Doped Carbon Materials.

The oxygen reduction reaction (ORR) is a core reaction for electrochemical energy technologies such as fuel cells and metal-air batteries. ORR catalysts have been limited to platinum, which meets the requirements of high activity and durability. Over the last few decades, a variety of materials have been tested as non-Pt catalysts, from metal-organic complex molecules to metal-free catalysts.

Atomic Force Microscopy Imaging and Analysis of Prokaryotic Genome Organization.

This protocol describes the application of atomic force microscopy for structural analysis of the prokaryotic and organellar nucleoids. It is based on a simple cell manipulation procedure that enables step-wise dissection of the nucleoid. The procedure includes (1) on-substrate-lysis of cells, and (2) enzyme treatment, followed by atomic force microscopy.

RecA Regulation by RecU and DprA During Natural Plasmid Transformation.

Natural plasmid transformation plays an important role in the dissemination of antibiotic resistance genes in bacteria. During this process, RecA physically interacts with RecU, RecX, and DprA. These three proteins are required for plasmid transformation, but RecA is not.

N-terminal dual lipidation-coupled molecular targeting into the primary cilium.

The primary cilium functions as an "antenna" for cell signaling, studded with characteristic transmembrane receptors and soluble protein factors, raised above the cell surface. In contrast to the transmembrane proteins, targeting mechanisms of nontransmembrane ciliary proteins are poorly understood. We focused on a pathogenic mutation that abolishes ciliary localization of retinitis pigmentosa 2 protein and revealed a dual acylation-dependent ciliary targeting pathway.

Cell type-specific suppression of mechanosensitive genes by audible sound stimulation.

Audible sound is a ubiquitous environmental factor in nature that transmits oscillatory compressional pressure through the substances. To investigate the property of the sound as a mechanical stimulus for cells, an experimental system was set up using 94.0 dB sound which transmits approximately 10 mPa pressure to the cultured cells.

Visualization of conformational variability in the domains of long single-stranded RNA molecules.

We demonstrate an application of atomic force microscopy (AFM) for the structural analysis of long single-stranded RNA (>1 kb), focusing on 28S ribosomal RNA (rRNA). Generally, optimization of the conditions required to obtain three-dimensional (3D) structures of long RNA molecules is a challenging or nearly impossible process. In this study, we overcome these limitations by developing a method using AFM imaging combined with automated, MATLAB-based image analysis algorithms for extracting information about the domain organization of single RNA molecules.

Transcriptional Repressor TrmBL2 from Thermococcus kodakarensis Forms Filamentous Nucleoprotein Structures and Competes with Histones for DNA Binding in a Salt- and DNA Supercoiling-dependent Manner.

Architectural DNA proteins play important roles in the chromosomal DNA organization and global gene regulation in living cells. However, physiological functions of some DNA-binding proteins from archaea remain unclear. Recently, several abundant DNA-architectural proteins including histones, Alba, and TrmBL2 have been identified in model euryarchaeon Thermococcus kodakarensis.