Size-Dependency of Electrochemically Grown Copper Nanoclusters Derived from Single Copper Atoms for the CO Reduction Reaction.

Electrochemically grown copper nanoclusters (CuNCs: < 3 nm) from single-atom catalysts have recently attracted intensive attention as electrocatalysts for CO2 and CO reduction reaction (CO2RR/CORR) because they exhibit distinct product selectivity compared with conventional Cu nanoparticles (typically larger than 10 nm). Herein, we conducted a detailed investigation into the size dependence of CuNCs on selectivity for multicarbon (C2+) production in CORR. These nanoclusters were electrochemically grown from single Cu atoms dispersed on covalent triazine frameworks (Cu-CTFs).

Engineering of acyl ligase domain in non-ribosomal peptide synthetases to change fatty acid moieties of lipopeptides.

Cyclic lipopeptides (CLPs) produced by the genus Bacillus are amphiphiles composed of hydrophilic amino acid and hydrophobic fatty acid moieties and are biosynthesised by non-ribosomal peptide synthetases (NRPSs). CLPs are produced as a mixture of homologues with different fatty acid moieties, whose length affects CLP activity. Iturin family lipopeptides are a family of CLPs comprising cyclic heptapeptides and β-amino fatty acids and have antimicrobial activity.

Recyclable and air-stable colloidal manganese nanoparticles catalyzed hydrosilylation of alkenes with tertiary silane.

We synthesized ,-dimethylformamide (DMF)-stabilized manganese nanoparticles (Mn NPs) in a one-step process under air using manganese(ii) chloride as the precursor. The Mn NPs were characterized in terms of particle size, oxidation state, and local structure using annular dark-field scanning transmission electron microscopy (ADF-STEM), X-ray photoelectron spectroscopy (XPS), and X-ray absorption spectroscopy (XAS). The results indicate that Mn NPs are divalent nanosized particles with Mn-O bonds.

An orally available P1'-5-fluorinated M inhibitor blocks SARS-CoV-2 replication without booster and exhibits high genetic barrier.

We identified a 5-fluoro-benzothiazole-containing small molecule, TKB272, through fluorine-scanning of the benzothiazole moiety, which more potently inhibits the enzymatic activity of SARS-CoV-2's main protease (M) and more effectively blocks the infectivity and replication of all SARS-CoV-2 strains examined including Omicron variants such as SARS-CoV-2 and SARS-CoV-2 than two M inhibitors: nirmatrelvir and ensitrelvir. Notably, the administration of ritonavir-boosted nirmatrelvir and ensitrelvir causes drug-drug interactions warranting cautions due to their CYP3A4 inhibition, thereby limiting their clinical utility. When orally administered, TKB272 blocked SARS-CoV-2 replication without ritonavir in B6.

Transient Kinetic QXAFS Approach for Understanding the RDE-MEA Gap in Fuel Cell (Oxygen Reduction Reaction) Performances of Pt-Based Electrocatalysts.

There is a large gap between the performances indicated by rotating disk electrode (RDE) results in acidic media and the actual performances obtained in membrane-electrode assemblies (MEAs) composed of the same electrocatalysts. It is unclear whether the intrinsic kinetic reactivity of the available surface Pt sites of Pt-based cathode electrocatalysts is similar or different at RDE and in MEA. To address this, we used an operando element-selective time-resolved Pt L-edge quick X-ray absorption fine structure (QXAFS) technique to determine transient response profiles and rate constants, , , and , corresponding to changes in the oxidation states [white line (WL) intensity] and local structures (coordination numbers of Pt-O and Pt-Pt bonds) at Pt sites for nine representative Pt-based cathode electrocatalysts under transient voltage operations, aiming to understand the oxygen reduction reaction (ORR) performance gap between RDE and MEA.

Local structure of amorphous sulfur in carbon-sulfur composites for all-solid-state lithium-sulfur batteries.

All-solid-state (ASS) batteries are a promising solution to achieve carbon neutrality. ASS lithium-sulfur (Li-S) batteries stand out due to their improved safety, achieved by replacing organic solvents, which are prone to leakage and fire, with solid electrolytes. In addition, these batteries offer the benefits of higher capacity and the absence of rare metals.

Hydration and Biodistribution of Zwitterionic Dendrimers Conjugating a Sulfobetaine Monomer and Polymers.

Zwitterionic polymers exhibit strong hydration, high biocompatibility, and antifouling properties. Dendrimers are regularly branched polymers, which are used in the drug delivery system (DDS). In this study, we synthesized zwitterionic monomer- and polymer-conjugated dendrimers as a biocompatible nanoparticle to investigate the relation between the hydration property and biodistribution.

Age-Related Changes in Lens Elasticity Contribute More to Accommodative Decline Than Shape Change.

Purpose: To determine whether lens biomechanical or geometric changes contribute to the decline in the accommodative capacity of the human eye, and to examine any differences in zonular function between different age groups.

Methods: Eighteen finite element whole eye models were developed to simulate the accommodative process. Six models were constructed in each of the two age cohorts, from the fourth and the sixth decades of life using data from ex vivo human lenses.

Hydrogen isotope separation at exceptionally high temperature using an unsaturated organometallic complex.

A new approach for hydrogen isotope separation using an unsaturated organometallic complex was proposed. Adsorption measurements of [Mn(dppe)(CO)(N)](BArF) (Mn-dppe) (dppe = 1,2-bis(diphenylphosphino)ethane, BArF = B[CH(3,5-CF)]) using H and D revealed a significant difference in the adsorption enthalpy of H/D at much higher room temperatures than in previous studies, with D molecules being more strongly adsorbed on unsaturated metal sites. Mixed gas adsorption isotherms were calculated at each temperature using IAST, and it was predicted that D uptake was much larger than H uptake.

Stabilization of oxygen vacancy ordering and electrochemical-proton-insertion-and-extraction-induced large resistance modulation in strontium iron cobalt oxides Sr(Fe,Co)O.

Electrochemically inserting and extracting hydrogen into and from solids are promising ways to explore materials' phases and properties. However, it is still challenging to identify the structural factors that promote hydrogen insertion and extraction and to develop materials whose functional properties can be largely modulated by inserting and extracting hydrogen through solid-state reactions at room temperature. In this study, guided by theoretical calculations on the energies of oxygen reduction and hydrogen insertion reactions with oxygen-deficient perovskite oxides, we demonstrated that the oxygen vacancy ordering in Sr(FeCo)O (SFCO) epitaxial films can be stabilized by increasing the Co content (x ≥ 0.

Synthesis and Characterization of Multifunctional Fluorescent-Magnetic Platinum Nanoclusters.

There is great interest in the development of new multifunctional fluorescent-magnetic nanomaterials for use as multimodal diagnostic imaging probes and site-specific drug delivery tools. Metal nanoclusters (NCs) have been reported to possess either fluorescent or magnetic properties, but not both. In this paper, we report the synthesis and characterization of multifunctional fluorescent-magnetic Pt NCs.

PtGd Alloy Nanoparticles from Organometallic Pt and Gd Complexes and Hollow Mesoporous Carbon Spheres: Enhanced Oxygen Reduction Reaction Activity and Durability.

PtGd alloy nanoparticles supported in hollow mesoporous carbon spheres (HMCS; ) were successfully prepared by the thermal reduction of organometallic Pt and Gd complexes without oxygen atoms supported in the pores of HMCS. The structures of PtGd alloy nanoparticles were fully characterized by TEM, HAADF-STEM-EDS, XRD, XAFS, and XPS, suggesting the formation of uniform PtGd alloy nanoparticles with an average particle size of 5.9 nm.

Dynamic properties of isotropic DMPC/DHPC bicelles: Insights from solution NMR and MD simulations.

Bicelles, an artificial disk-shaped lipid bilayer, are commonly used for the structural and functional characterization of membrane-bound proteins in an environment similar to that in intracellular membranes. Because the dynamics of the lipids that constitute bicelles exert a significant impact on the structure and function of the inserted proteins, we investigated the mobility of lipid molecules in bicelles composed of DMPC (14:0 PC) and DHPC (06:0 PC) using solution NMR and MD calculations. C R relaxation experiments for the acyl groups demonstrated that increasing bicelle sizes limit the rotational diffusion of acyl chain H-C bonds in DMPC.

Iron redox effect on the structure and viscosity of a sodium silicate glass and melt.

The viscosity of silicate melts is one of the most important physical properties for understanding high-temperature phenomena in magmatic systems and material processing. The effects of composition and temperature on viscosity have long been elucidated. Although iron ions are the main components of magmatic systems, their influence on viscosity remains unclear because the behavior of iron is complicated; iron ions have two redox states, Fe3+ and Fe2+.

Diffractometer for element-specific analysis on local structures using a combination of X-ray fluorescence holography and anomalous X-ray scattering.

To tackle disorder in crystals and short- and intermediate-range order in amorphous materials, such as glass, we developed a carry-in diffractometer to utilise X-ray fluorescence holography (XFH) and anomalous X-ray scattering (AXS), facilitating element-specific analyses with atomic resolution using the wavelength tunability of a synchrotron X-ray source. Our diffractometer unifies XFH and AXS configurations to determine the crystal orientation via diffractometry. In particular, XFH was realised even for a crystal with blurred emission lines by a standing wave in a hologram, and high-throughput AXS with sufficient count statistics and energy resolution was achieved using three multi-array detectors with crystal analysers.

Binding of a potential antibacterial drug, mangiferin, to serine hydroxymethyltransferase from Enterococcus faecium.

Serine hydroxymethyltransferase (SHMT) plays a critical role in the 1C metabolism pathway. This pathway is involved in the synthesis of many amino and nucleic acids, and SHMT is considered a target for drugs through folate metabolism, especially for cancer and malaria. A detailed analysis of the interactions between SHMTs and drugs will greatly contribute to the development of new drugs.

Dynamic Local Order and Ultralow Thermal Conductivity of CsAgBiBr.

Lead halide perovskites are renowned for their exceptional optoelectronic properties but face concerns over lead toxicity and stability, which drives the exploration of lead-free perovskites, with CsAgBiBr standing out as a benchmark alternative. Understanding the structural dynamics and thermal transport properties of CsAgBiBr is crucial but remains an outstanding challenge due to the complex atomic fluctuations. Here, through diffuse scattering experiments and simulations, we uncover the underlying dynamic local structure in CsAgBiBr, showing a unique two-dimensional spatial correlation.

Tuning of a Hydrogen-Bonded Organic Framework by Liquid-Assisted Mechanosynthesis between Trans-Aconitic Acid and Isonicotinamide.

Cocrystallization of trans-aconitic acid (TACA) and isonicotinamide (INA) using liquid assisted mechanochemical grinding results in a unique supramolecular hydrogen-bonded organic framework (HOF) system encapsulating various organic solvents (liquid guest) with the formation of channel inclusion compounds. Dimension and shape of the framework is dependent on the solvent used during liquid assisted grinding (LAG). Although crystal structure of the cocrystal (TACA) ⋅ (INA) ⋅ (HO)@(INA) has been determined by Single Crystal X-ray diffraction (SCXRD), crystal structures of 3 cocrystal HOFs were determined by microcrystal electron diffraction (MicroED) and synchrotron X-ray diffraction due to lack of suitable single crystal.

Near-Infrared Light-Induced Spin-State Switching Based on Fe(II)-Hg(II) Spin-Crossover Network.

The development of molecular switches with tunable properties has garnered considerable interest over several decades. A novel spin-crossover (SCO) material based on iron(II) complexes incorporating 4-acetylpyridine (4-acpy) and [Hg(SCN)] anions was synthesized and formulated as [Fe(4-acpy)][Hg(μ-SCN)] (1). Compound 1 is crystallized in a three-dimensional network in the non-centrosymmetric orthorhombic space group Pna2 with two octahedral [Fe(4-acpy)(NCS)] entities featuring two distinct Fe centers (Fe1 and Fe2).

Single-Sided Delocalized Polarization of the C Cage and Reduced Infrared Intensities and Dipole Moment of HO@C.

The C fullerene cage can encapsulate a small molecule like water and provides room to leave the encapsulated component rather isolated, but the true nature of the intracomplex interactions should be further elucidated for better understanding and utility of this series of complexes. Here, an analysis toward this goal is conducted for HO@C by infrared spectral measurements and theoretical calculations. It is shown that the response of the π electrons of the C cage upon encapsulating a water molecule is single-sided and delocalized in that the electron density is partially transferred from the - side to the + side of the cage (when the axis is taken along the water dipole) but almost only inside the cage, explaining the significant reduction of the dipole moment and the infrared intensities.

Supercritical density fluctuations and structural heterogeneity in supercooled water-glycerol microdroplets.

Recent experiments and theoretical studies strongly indicate that water exhibits a liquid-liquid phase transition (LLPT) in the supercooled domain. An open question is how the LLPT of water can affect the properties of aqueous solutions. Here, we study the structural and thermodynamic properties of supercooled glycerol-water microdroplets at dilute conditions (χ = 3.

Time-Resolved Probing of the Iodobenzene C-Band Using XUV-Induced Electron Transfer Dynamics.

Time-resolved extreme ultraviolet spectroscopy was used to investigate photodissociation within the iodobenzene C-band. The carbon-iodine bond of iodobenzene was photolyzed at 200 nm, and the ensuing dynamics were probed at 10.3 nm (120 eV) over a 4 ps range.

Antiferromagnetic spin-torque diode effect in a kagome Weyl semimetal.

Spintronics based on ferromagnets has enabled the development of microwave oscillators and diodes. To achieve even faster operation, antiferromagnets hold great promise despite their challenging manipulation. So far, controlling antiferromagnetic order with microwave currents remains elusive.

A van der Waals porous crystal featuring conformational flexibility and permanent porosity for ultrafast water release.

Flexibility has been pursued enthusiastically in the field of porous crystals for enhancing their adsorption and separation performances. However, flexibility has never been observed among porous crystals sustained thoroughly by van der Waals interactions since flexible motions readily lead to the collapse of the porous architecture. Here we report a van der Waals crystal featuring conformational flexibility as well as permanent microporosity.