Diabatic and adiabatic transitions between Floquet states imprinted in coherent exciton emission in monolayer WSe₂

光を着た電子状態の飛び移りを世界で初めて観測に成功 --赤外光パルスによる電子状態制御へ--. 京都大学プレスリリース. 2022-12-28.Floquet engineering is a promising way of controlling quantum system with photon-dressed states on an ultrafast time scale. So far, the energy structure of Floquet states in solids has been intensively investigated. However, the dynamical aspects of the photon-dressed states under ultrashort pulse have not been explored yet. Their dynamics become highly sensitive to the driving field transients, and thus, understanding them is crucial for ultrafast manipulation of a quantum state. Here, we observed the coherent exciton emission in monolayer WSe₂ at room temperature at the appropriate photon energy and the field strength of the driving light pulse using high-harmonic spectroscopy. Together with numerical calculations, our measurements revealed that the coherent exciton emission spectrum reflects the diabatic and adiabatic dynamics of Floquet states of excitons. Our results provide a previosuly unexplored approach to Floquet engineering and lead to control of quantum materials through pulse shaping of the driving field

Complement in patients receiving maintenance hemodialysis: functional screening and quantitative analysis

<p>Abstract</p> <p>Background</p> <p>The complement system is vital for innate immunity and is implicated in the pathogenesis of inflammatory diseases and the mechanism of host defense. Complement deficiencies occasionally cause life-threatening diseases. In hemodialysis (HD) patients, profiles on complement functional activity and deficiency are still obscure. The objectives of the present study were to measure the functional complement activities of the classical pathway (CP), lectin pathway (LP) and alternative pathway (AP) using a novel method and consequently to elucidate the rates of deficiencies among HD patients.</p> <p>Methods</p> <p>In the present study, 244 HD patients at one dialysis center and 204 healthy controls were enrolled. Functional complement activities were measured simultaneously using the Wielisa^®-kit. The combination of the results of these three pathway activities allows us to speculate which candidate complement is deficient; subsequently, the deficient complement was determined.</p> <p>Results</p> <p>All three functional complement activities were significantly higher in the HD patients than in the control group (P < 0.01 for all cases). After identifying candidates in both groups with complement deficiencies using the Wielisa^®-kit, 16 sera (8.8%) with mannose-binding lectin (MBL) deficiency, 1 serum (0.4%) with C4 deficiency, 1 serum (0.4%) with C9 deficiency, and 1 serum (0.4%) with B deficiency were observed in the HD group, and 18 sera (8.8%) with MBL deficiency and 1 serum (0.5%) with B deficiency were observed in the control group. There were no significant differences in the 5-year mortality rate between each complement-deficient group and the complement-sufficient group among the HD patients.</p> <p>Conclusion</p> <p>This is the first report that profiles complement deficiencies by simultaneous measurement of functional activities of the three complement pathways in HD patients. Hemodialysis patients frequently suffer from infections or malignancies, but functional complement deficiencies do not confer additional risk of mortality.</p

Effect of incoherent electron-hole pairs on high harmonic generation in atomically thin semiconductors

High harmonic generation (HHG) in solids reflects the underlying nonperturbative nonlinear dynamics of electrons in a strong light field and is a powerful tool for ultrafast spectroscopy of electronic structures. Photo-carrier doping allows us to understand the carrier dynamics and their correlations in the HHG process. Here, we study the effects of incoherent electron-hole pairs on HHG in an atomically thin semiconductor. The experimentally observed response to photo-carrier doping is successfully reproduced in numerical simulations incorporating the photo-excited carrier distribution and electron-electron scattering effects. The simulation results reveal that the intraband current is largely suppressed by the momentum relaxation process. We also clarify that the excitation-induced dephasing process rather than the phase-space filling effect is the dominant mechanism reducing the higher order harmonics above the absorption edge. Our work provides a basic understanding of high harmonic spectroscopy and the optimum conditions for generating extreme ultraviolet light from solids

Japanese Attitudes toward Genetic Engineering

Abstract Whether or not the general public supports biotechnology and genetic engineering is an important current problem. In this paper, we report that people&apos;s attitudes toward the terms &quot;biotechnology&quot; and &quot;genetic engineering&quot; are highly dependent upon their knowledge of the fields. For this reason, it is necessary to promote activities that provide the general public with information on the current states of biotechnology and genetic engineering so that they can form educated opinions

Machine learning-based prediction of the electron energy distribution function and electron density of argon plasma from the optical emission spectra

Arellano F.J., Kusaba M., Wu S., et al. Journal of Vacuum Science and Technology A 42, 053001 (2024) https://doi.org/10.1116/6.0003731.Optical emission spectroscopy (OES) is a highly valuable tool for plasma characterization due to its nonintrusive and versatile nature. The intensities of the emission lines contain information about the parameters of the underlying plasma-electron density n e and temperature or, more generally, the electron energy distribution function (EEDF). This study aims to obtain the EEDF and n e from the OES data of argon plasma with machine learning (ML) techniques. Two different models, i.e., the Kernel Regression for Functional Data (KRFD) and an artificial neural network (ANN), are used to predict the normalized EEDF and Random Forest (RF) regression is used to predict n e . The ML models are trained with computed plasma data obtained from Particle-in-Cell/Monte Carlo Collision simulations coupled with a collisional-radiative model. All three ML models developed in this study are found to predict with high accuracy what they are trained to predict when the simulated test OES data are used as the input data. When the experimentally measured OES data are used as the input data, the ANN-based model predicts the normalized EEDF with reasonable accuracy under the discharge conditions where the simulation data are known to agree well with the corresponding experimental data. However, the capabilities of the KRFD and RF models to predict the EEDF and n e from experimental OES data are found to be rather limited, reflecting the need for further improvement of the robustness of these models

Development of small fluorescent probes for the analysis of autophagy kinetics

Summary: Autophagy is a dynamic process that degrades subcellular constituents, and its activity is measured by autophagic flux. The tandem proteins RFP-GFP-LC3 and GFP-LC3-RFP-LC3ΔG, which enable the visualization of autophagic vacuoles of different stages by differences in their fluorescent color, are useful tools to monitor autophagic flux, but they require plasmid transfection. In this study, we hence aimed to develop a new method to monitor autophagic flux using small cell-permeable fluorescent probes. We previously developed two green-fluorescent probes, DALGreen and DAPGreen, which detect autolysosomes and multistep autophagic vacuoles, respectively. We here developed a red-fluorescent autophagic probe, named DAPRed, which recognizes various autophagic vacuoles. By the combinatorial use of these green- and red-fluorescent probes, we were able to readily detect autophagic flux. Furthermore, these probes were useful not only for the visualization of canonical autophagy but also for alternative autophagy. DAPRed was also applicable for the detection of autophagy in living organisms