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We search for ultralight scalar dark matter candidates that induce oscillations of the fine structure constant, the electron and quark masses, and the quantum chromodynamics energy scale with frequency comparison data between a ^{171}Yb optical lattice clock and a ^{133}Cs fountain microwave clock that span 298 days with an uptime of 15.4%. New limits on the couplings of the scalar dark matter to electrons and gluons in the mass range from 10^{-22} to 10^{-20}  eV/c^{2} are set, assuming that each of these couplings is the dominant source of the modulation in the frequency ratio. The absolute frequency of the ^{171}Yb clock transition is also determined as 518 295 836 590 863.69(28) Hz, which is one of the important contributions toward a redefinition of the second in the International System of Units.

Deterioration of drugs due to light exposure is one of the major concerns, especially regarding protection of high-calorie infusion solutions, lightproof covers are used in hospitals. In the absence of any set standards regarding their usage, they are often reused. This study aimed to investigate bacterial contamination of lightproof covers used in hospital wards. For this, lightproof covers which had been used or stored in wards were collected and bacterial cultures were carried out from them. Examination of the cultures revealed that bacteria were present in the used lightproof covers. The bacterial species detected in the used lightproof covers were Bacillus species Coagulase-negative Staphylococci (CNS) and Methicillin-resistant Staphylococcus aureus (MRSA). Bacillus species and CNS were also detected in lightproof covers stored in wards, whereas MRSA was not detected. Intestinal bacteria were detected in only one lightproof cover. However, no bacteria were detected from either inside or outside of the unused lightproof covers that were stored in the drugs department. After allowing the unused lightproof covers stored in the drugs department to stand for 24 h, Bacillus species and CNS were detected in only one of the covers, whereas no bacteria was detected in other covers. These results indicate that there is a risk of bacterial contamination in the reuse of lightproof covers and that they should either be disposed off properly after usage or hand, finger disinfectants should be used while handling them to prevent any possible contamination., Competing Interests: Competing Interests: The authors have declared that no competing interest exists., (© The author(s).)

It has over the last few years been reported that the application of a DC electric field and resulting current over a bed of certain catalyst-support systems enhances catalytic activity for several reactions involving hydrogen-containing reactants, and the effect has been attributed to surface protonic conductivity on the porous ceramic support (typically ZrO2, CeO2, SrZrO3). Models for the nature of the interaction between the protonic current, the catalyst particle (typically Ru, Ni, Co, Fe), and adsorbed reactants such as NH3 and CH4 have developed as experimental evidence has emerged. Here, we summarize the electrical enhancement and how it enhances yield and lowers reaction temperatures of industrially important chemical processes. We also review the nature of the relevant catalysts, support materials, as well as essentials and recent progress in surface protonics. It is easily suspected that the effect is merely an increase in local vs. nominal set temperature due to the ohmic heating of the electrical field and current. We address this and add data from recent studies of ours that indicate that the heating effect is minor, and that the novel catalytic effect of a surface protonic current must have additional causes.

Superhigh-ε materials that exhibit exceptionally high dielectric permittivity are recognized as potential candidates for a wide range of next-generation photonic and electronic devices. In general, achieving a high-ε state requires low material symmetry, as most known high-ε materials are symmetry-broken crystals. There are few reports on fluidic high-ε dielectrics. Here, we demonstrate how small molecules with high polarity, enabled by rational molecular design and machine learning analyses, enable the development of superhigh-ε fluid materials (dielectric permittivity, ε > 10 4 ) with strong second harmonic generation and macroscopic spontaneous polar ordering. The polar structures are confirmed to be identical for all the synthesized materials. Furthermore, adapting this strategy to high-molecular weight systems allows us to generalize this approach to polar polymeric materials, creating polar soft matters with spontaneous symmetry breaking., (Copyright © 2021 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works. Distributed under a Creative Commons Attribution NonCommercial License 4.0 (CC BY-NC).)

Low temperature (<500 K) methane steam reforming in an electric field was investigated over various catalysts. To elucidate the factors governing catalytic activity, activity tests and various characterization methods were conducted over various oxides including CeO 2 , Nb 2 O 5 , and Ta 2 O 5 as supports. Activities of Pd catalysts loaded on these oxides showed the order of CeO 2 > Nb 2 O 5 > Ta 2 O 5. Surface proton conductivity has a key role for the activation of methane in an electric field. Proton hopping ability on the oxide surface was estimated using electrochemical impedance measurements. Proton transport ability on the oxide surface at 473 K was in the order of CeO 2 > Nb 2 O 5 > Ta 2 O 5. The OH group amounts on the oxide surface were evaluated by measuring pyridine adsorption with and without H 2 O pretreatment. Results indicate that the surface OH group concentrations on the oxide surface were in the order of CeO 2 > Nb 2 O 5 > Ta 2 O 5. These results demonstrate that the surface concentrations of OH groups are related to the proton hopping ability on the oxide surface. The concentrations reflect the catalytic activity of low-temperature methane steam reforming in the electric field., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)

Catalytic methane steam reforming was conducted at low temperature using a Pd catalyst supported on Ce 1- x M x O 2 ( x = 0 or 0.1, M = Ca, Ba, La, Y or Al) oxides with or without an electric field (EF). The effects of the catalyst support on catalytic activity and surface proton hopping were investigated. Results show that Pd/Al-CeO 2 (Pd/Ce 0.9 Al 0.1 O 2 ) showed higher activity than Pd/CeO 2 with EF, although their activity was identical without EF. Thermogravimetry revealed a larger amount of H 2 O adsorbed onto Pd/Al-CeO 2 than onto Pd/CeO 2 , so Al doping to CeO 2 contributes to greater H 2 O adsorption. Furthermore, electrochemical conduction measurements of Pd/Al-CeO 2 revealed a larger contribution of surface proton hopping than that for Pd/CeO 2 . This promotes the surface proton conductivity and catalytic activity during EF application., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)

Low-temperature heterogeneous catalytic reaction in an electric field is anticipated as a novel approach for on-demand and small-scale catalytic processes. This report quantitatively reveals the important role of proton coverage on the catalyst support for catalytic ammonia synthesis in an electric field, which shows an anti-Arrhenius behaviour.

This is the first direct observation that surface proton hopping occurs on SrZrO 3 perovskite even under a H 2 (i.e. dry) atmosphere. Understanding proton conduction mechanisms on ceramic surfaces under a H 2 atmosphere is necessary to investigate the role of proton hopping on the surface of heterogeneous catalysts in an electric field. In this work, surface protonics was investigated using electrochemical impedance spectroscopy (EIS). To extract the surface proton conduction, two pellets of different relative densities were prepared: a porous sample (R.D. = 60%) and a dense sample (R.D. = 90%). Comparison of conductivities with and without H 2 revealed that only the porous sample showed a decrease in the apparent activation energy of conductivity by supplying H 2 . H/D isotope exchange tests revealed that the surface proton is the dominant conductive species over the porous sample with H 2 supply. Such identification of a dominant conductive carrier facilitates consideration of the role of surface protonics in chemical reactions.

We demonstrate an 8-branch Er:fiber frequency comb with seven application ports, which can be individually optimized for applications with different wavelengths. The beat between the comb and a cw laser has a signal-to-noise ratio exceeding 30 dB at a resolution bandwidth of 300 kHz. The 8-branch frequency comb is used to perform frequency locking for four repumping and lattice lasers, and the frequency measurement of two clock lasers of strontium and ytterbium optical lattice clocks. We have achieved reliable optical lattice clock operation, thanks to the stable frequency locking and measurement obtained by using the 8-branch frequency comb. The developed frequency comb is a powerful experimental tool for various applications, including not only optical lattice clocks, but also research on quantum optics that use many frequency-stabilized lasers.

We report an uncertainty evaluation of an 171 Yb optical lattice clock with a total fractional uncertainty of 3.6×10 -16 , which is mainly limited by the lattice-induced light shift and the blackbody radiation shift. Our evaluation of the lattice-induced light shift, the density shift, and the second-order Zeeman shift is based on an interleaved measurement where we measure the frequency shift using the alternating stabilization of a clock laser to the 6s 2 1 S 0 -6s6p 3 P 0 clock transition with two different experimental parameters. In the present evaluation, the uncertainties of two sensitivity coefficients for the lattice-induced hyperpolarizability shift d incorporated in a widely used light shift model by RIKEN and the second-order Zeeman shift a Z are improved compared with the uncertainties of previous coefficients. The hyperpolarizability coefficient d is determined by investigating the trap potential depth and the light shifts at the lattice frequencies near the two-photon transitions 6s6p 3 P 0 -6s8p 3 P 0 , 6s8p 3 P 2 , and 6s5f 3 F 2 . The obtained values are d=-1.1(4) μ Hz and a Z =-6.6(3) Hz/mT 2 . These improved coefficients should reduce the total systematic uncertainties of Yb lattice clocks at other institutes.

Frequency offset locking between two Nd:YAG lasers is performed using frequency locking with an electrical delay line. The relative frequency instability of the offset locking is measured to be 3.5×10 -12 for an averaging time of 1 s, which is approximately 77 times smaller than that of the free-running case. The frequency instability of the frequency locking is compared to that of the phase locking between the two Nd:YAG lasers. Furthermore, a compact solid-state laser is frequency locked to an optical frequency comb with a frequency instability of 8.2×10 -11 for an averaging time of 1 s, which is improved by approximately 20 times, with respect to the free-running case. The offset-locking scheme using a delay line is useful for various applications including a research on quantum optics, interferometric measurements, and experiments involving laser cooling, such as an optical lattice clock.

We have developed an optical lattice clock that can operate in dual modes: a strontium (Sr) clock mode and an ytterbium (Yb) clock mode. Dual-mode operation of the Sr-Yb optical lattice clock is achieved by alternately cooling and trapping 87 Sr and 171 Yb atoms inside the vacuum chamber of the clock. Optical lattices for Sr and Yb atoms were arranged with horizontal and vertical configurations, respectively, resulting in a small distance of the order of between the trapped Sr and Yb atoms. The 1 S 0 - 3 P 0 clock transitions in the trapped atoms were interrogated in turn and the clock lasers were stabilized to the transitions. We demonstrated the frequency ratio measurement of the Sr and Yb clock transitions by using the dual-mode operation of the Sr-Yb optical lattice clock. The dual-mode operation can reduce the uncertainty of the blackbody radiation shift in the frequency ratio measurement, because both Sr and Yb atoms share the same blackbody radiation.