To describe the trend of cumulative incidence of coronavirus disease 19 (COVID-19) and undiagnosed cases over the pandemic through the emergence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants among healthcare workers in Tokyo, we analysed data of repeated serological surveys and in-house COVID-19 registry among the staff of National Center for Global Health and Medicine. Participants were asked to donate venous blood and complete a survey questionnaire about COVID-19 diagnosis and vaccine. Positive serology was defined as being positive on Roche or Abbott assay against SARS-CoV-2 nucleocapsid protein, and cumulative infection was defined as either being seropositive or having a history of COVID-19. Cumulative infection has increased from 2.0% in June 2021 (pre-Delta) to 5.3% in December 2021 (post-Delta). After the emergence of the Omicron, it has increased substantially during 2022 (16.9% in June and 39.0% in December). As of December 2022, 30% of those who were infected in the past were not aware of their infection. Results indicate that SARS-CoV-2 infection has rapidly expanded during the Omicron-variant epidemic among healthcare workers in Tokyo and that a sizable number of infections were undiagnosed.

To investigate molecular composition of low-metallicity environments, we conducted spectral line survey observations in the 3 mm band toward three dwarf galaxies, the Large Magellanic Cloud, IC 10, and NGC 6822 with the Mopra 22 m, the Nobeyama 45 m and the IRAM 30 m, respectively. The rotational transitions of CCH, HCN, HCO+, HNC, CS, SO, 13CO, and 12CO were detected in all three galaxies. We found that the spectral intensity patterns are similar to one another regardless of star formation activities. Compared with Solar-metallicity environments, the molecular compositions of dwarf galaxies are characterized by (1) deficient nitrogen-bearing molecules and (2) enhanced CCH and suppressed CH3OH. These are interpreted (1) as a direct consequence of the lower elemental abundance of nitrogen, and (2) as a consequence of extended photon dominated regions in cloud peripheries due to the lower abundance of dust grains, respectively.

Coupling superconductors to quantum Hall edge states is the subject of intense investigation as part of the ongoing search for non-abelian excitations. Our group has previously observed supercurrents of hundreds of picoamperes in graphene Josephson junctions in the quantum Hall regime. One of the explanations of this phenomenon involves the coupling of an electron edge state on one side of the junction to a hole edge state on the opposite side. In our previous samples, these states are separated by several microns. Here, a narrow trench perpendicular to the contacts creates counterpropagating quantum Hall edge channels tens of nanometres from each other. Transport measurements demonstrate a change in the low-field Fraunhofer interference pattern for trench devices and show a supercurrent in both trench and reference junctions in the quantum Hall regime. The trench junctions show no enhancement of quantum Hall supercurrent and an unexpected supercurrent periodicity with applied field, suggesting the need for further optimization of device parameters.

We have detected [C I] 3P1–3P0 emissions in the gaseous debris disks of 49 Ceti and β Pictoris with the 10 m telescope of the Atacama Submillimeter Telescope Experiment, which is the first detection of such emissions. The line profiles of [C I] are found to resemble those of CO(J=3–2) observed with the same telescope and the Atacama Large Millimeter/submillimeter Array. This result suggests that atomic carbon (C) coexists with CO in the debris disks, and is likely formed by the photodissociation of CO. Assuming an optically thin [C I] emission with the excitation temperature ranging from 30 to 100 K, the column density of C is evaluated to be (2.2 ± 0.2) × 1017 and (2.5 ± 0.7) × 1016 cm−2 for 49 Ceti and β Pictoris, respectively. The C/CO column density ratio is thus derived to be 54 ± 19 and 69 ± 42 for 49 Ceti and β Pictoris, respectively. These ratios are higher than those of molecular clouds and diffuse clouds by an order of magnitude. The unusually high ratios of C to CO are likely attributed to a lack of H2 molecules needed to reproduce CO molecules efficiently from C. This result implies a small number of H2 molecules in the gas disk; i.e., there is an appreciable contribution of secondary gas from dust grains.

PtCu nanoparticles were synthesized with different pH and support conditionsusing radiochemical process. The nanoparticle structures were characterized bytransmission electron microscopy, inductively coupled plasma atomic emissionspectrometry, X-ray absorption spectroscopy, and X-ray diffraction techniques.The nanoparticle structure was relevant to the pH of the precursor solutions.The lattice parameter of PtCu alloy increased in high pH samples, whichindicates the critical effect of metal ion adsorption in precursor solution onnanoparticle structure.

Antiviral activity of metallic Ag nanoparticles immobilized on textile fabrics were investigated. The Ag nanoparticles synthesized by radiochemical process are firmly immobilized on the surface of support textile fabrics of cotton. Small Ag particles of about 2–4 nm were observed together with relatively large particles of more than 10 nm. The Ag nanoparticles showed antiviral activity against Influenza A and Feline Calicivirus. The antiviral activity significantly depended on the concentration of the Eagle’s minimal essential medium. It was implied that the surface passivation by inhibitory agent lead to the deactivation of metallic Ag nanoparticles.

Secretory IgA in the saliva is essential for protection from mucosally transmitted pathogens and maintaining homeostasis at mucosal surfaces of the oral cavity. Expression of submandibular gland polymeric Ig receptor (pIgR) is essential for IgA secretion. In the present study, we investigated the influence of indigestible carbohydrates on IgA production in the salivary gland and saliva. Five-week-old rats were fed a fibre-free diet (control), or a diet with 5 % (w/w) fructo-oligosaccharide (FOS) or a combination of 2·5 % (w/w) polydextrose (PDX) and 2·5 % (w/w) lactitol for 21-d. IgA concentrations in the caecal digesta, submandibular gland tissue, and saliva in the FOS and PDX+lactitol diet groups were significantly higher than those in the control group (P< 0·05). The increase in IgA in the submandibular gland tissue was confirmed using immunohistochemical analysis. However, the IgA concentrations of serum did not differ between the FOS or PDX+lactitol groups and the control group (P= 0·5). In the FOS and PDX+lactitol groups, the pIgR mRNA (pIgR/β-actin) expression level in the submandibular gland tissue was significantly higher than that in the control group (P< 0·05). The present study suggests that indigestible carbohydrates play an important role in the increase in IgA concentrations in the submandibular gland tissue, saliva, and caecal digesta.

Electrode catalysts composed of carbon supported PtRu nanoparticles (PtRu/C) synthesized by radiochemical process were annealed to control the PtRu substructure to enhance catalytic activity. The substructure of the PtRu nanoparticles synthesized by using high-energy electron beam under acidic condition was Pt-rich core/Ru-rich shell type, reflecting the redox potentials of each precursor ions. The material characterization techniques revealed that the reductive annealing led to the mixing of PtRu both in the core and on the surface. The sample with annealing temperature of 300°C for 5 hour showed the highest methanol oxidation current, 2.3 times higher than that obtained with before annealing.

Carbon supported Pt-SnO2 electrocatalysts with different Sn/Pt molar ratios were prepared by an electron beam irradiation method. Dissolved gas conditions in the vials irradiated with electron beam were controlled to air or Ar. The results of the material analyses showed that both Pt and SnO2 were immobilized onto carbon support in all catalysts. Bubbling Ar to the precursor solution led to steady change of metal contents in response to the precursor concentrations. The ethanol oxidation activity plotted against Sn/Pt ratio behaved differently with dissolved gas condition of the vial. This difference is discussed with supposed existing state of SnO2 in connection with the reduction process of Pt and Sn.

We have studied a procedure to determine Tight-Binding (TB) parameters automatically, by which the band structure of the crystalline solid can be reproduced so as to be good agreement with that of first-principles molecular dynamics calculation. According to this procedure, we determine TB parameter sets for silicon and diamond accurately, and a fairly good set for their compound SiC.

HoxEr1-xN (x=0.25, 0.5, 0.75) samples were synthesized by nitriding of HoxEr1-x alloy bars and their thermal conductivity κ were measured. The measured κ values were comparable to those of stainless steel and Er3Ni. Ho0.5Er0.5N showed the highest κ of the present three samples. The thermal diffusivity calculated from the κ and the specific heat indicates that Ho0.5Er0.5N is a very promising regenerator material for the cryocoolers. The electrical resistivity ρ was also measured as a function of temperature.

Crystal structure change with an applied electric field was investigated by Raman spectroscopy and X-ray diffraction (XRD) for the 1 μm-thick (100)/(001) one-axis oriented tetragonal Pb(Zr0.3Ti0.7)O3 films prepared on Pt-covered (100) Si substrates by chemical solution deposition technique. As-deposited films were under the strained condition in good agreement with the estimation from the thermal strain applied under the cooling process after the deposition from the Curie temperature to the room temperature. This strain was ascertained to be relaxed by an applied electric field in accompanying with the dramatic increase of the volume fraction of (001) orientation. These results demonstrate the importance of the crystal structure measurement not only as-deposited films, but also after applied electric field, such as after poling.

This review article starts with the discovery of Bacillus thuringiensis Berliner in Japan at the turn of the century and notes that the observations of the early Japanese workers clearly show that they were aware of the toxin-mediated nature of the activity of B. thuringiensis toward insect larvae. The early work in Europe with B. thuringiensis against Ostrinia nubilalis (Hubner) showed that the bacterium had promise as a microbial control agent. The commercial development of B. thuringiensis in France in the late 1930s, and in Eastern Europe and the United States in the 1950s, is traced.

Raman scattering spectra and ferroelectric properties of epitaxial tetragonal Pb(Zr, Ti)O3 were investigated for polar axis-oriented thin films with various Zr/(Zr + Ti) ratios and by changing the ratios from 0 to 0.50 at different measurement temperatures. The chosen films in the thickness range of 1–2 μm present the advantage of showing small residual strain. The E (TO) modes were successfully isolated using cross-polarization configurations, while A1 (TO) and B1 modes were activated using parallel polarization configurations. Systematic changes in Raman peak positions were observed with changes in the Zr/(Zr + Ti) ratios at different measurement temperatures. It was found in both cases that the tetragonal distortion (c/a-1) and the value of square of spontaneous polarization (Ps2) linearly increased with increasing ω2[A1(1TO)], where a and c are the lattice parameters of a and c-axes. This indicates that monitoring A1(1TO) mode is efficient as a characterization method of ferroelectricity. It can also be used as a novel nondestructive process check or reliability assessment technique during fabrication of microelectromechanical systems (MEMS) using piezoelectric materials.

A nanoparticle catalyst of PtRuAu/C was synthesized by including an Au precursor in the radiolytic process for preparing a PtRu/C catalyst. Their methanol oxidation activity and electrochemical durability were measured by linear sweep voltammetry before and after potential cycling treatment. PtRuAu/C had a significantly higher durability than PtRu/C while maintaining a comparable high activity. The morphology and substructure of the nanoparticles were investigated by energy-dispersive x-ray spectroscopy, x-ray diffraction, and x-ray absorption fine structure spectroscopy. Metallic nanoparticles with diameters of about 2 nm were obtained; they probably had Pt-core/PtRu-shell structures. Transmission electron microscopy observations after potential cycling revealed that 2-nm-diameter nanoparticles containing Au did not coarsen, whereas nanoparticles without Au coarsened significantly to 3.7 nm. Some crystal defaults were observed in the coarsened particles, implying that the coarsening was caused by Ostwald ripening. The Au addition to catalyst particles consisting of PtRu inhibits coarsening and consequently improves the electrochemical durability.