Early-phase changes of extravascular lung water index as a prognostic indicator in acute respiratory distress syndrome patients

Background: The features of early-phase acute respiratory distress syndrome (ARDS) are leakage of fluid into the extravascular space and impairment of its reabsorption, resulting in extravascular lung water (EVLW) accumulation. The current study aimed to identify how the initial EVLW values and their change were associated with mortality. Methods: This was a post hoc analysis of the PiCCO Pulmonary Edema Study, a multicenter prospective cohort study that included 23 institutions. Single-indicator transpulmonary thermodilution-derived EVLW index (EVLWi) and conventional prognostic factors were prospectively collected over 48 h after enrollment. Associations between 28-day mortality and each variable including initial (on day 0), mean, maximum, and Δ (subtracting day 2 from day 0) EVLWi were evaluated. Results: We evaluated 192 ARDS patients (median age, 69 years (quartile, 24 years); Sequential Organ Failure Assessment (SOFA) score on admission, 10 (5); all-cause 28-day mortality, 31%). Although no significant differences were found in initial, mean, or maximum EVLWi, Δ-EVLWi was significantly higher (i.e., more reduction in EVLWi) in survivors than in non-survivors (3.0 vs. ?0.3 mL/kg, p = 0.006). Age, maximum, and Δ-SOFA scores and Δ-EVLW were the independent predictors for survival according to the Cox proportional hazard model. Patients with Δ-EVLWi > 2.8 had a significantly higher incidence of survival than those with Δ-EVLWi ? 2.8 (log-rank test, χ2 = 7.08, p = 0.008). Conclusions: Decrease in EVLWi during the first 48 h of ARDS may be associated with 28-day survival. Serial EVLWi measurements may be useful for understanding the pathophysiologic conditions in ARDS patients. A large multination confirmative trial is required

Understanding Novel Superconductors with Ab Initio Calculations

This chapter gives an overview of the progress in the field of computational superconductivity. Following the MgB2 discovery (2001), there has been an impressive acceleration in the development of methods based on Density Functional Theory to compute the critical temperature and other physical properties of actual superconductors from first-principles. State-of-the-art ab-initio methods have reached predictive accuracy for conventional (phonon-mediated) superconductors, and substantial progress is being made also for unconventional superconductors. The aim of this chapter is to give an overview of the existing computational methods for superconductivity, and present selected examples of material discoveries that exemplify the main advancements.Comment: 38 pages, 10 figures, Contribution to Springer Handbook of Materials Modellin

Radiation Hardness of 4H-SiC JFETs in MGy Dose Ranges

Silicon carbide junction field effect transistors (SiC JFETs) were irradiated with gamma-rays up to 9 MGy (H2O). With increasing dose, apparent shift of drain current- gate voltage (ID-VG) curves to negative voltage side as observed for SiC metal oxide semiconductor (MOS) FETs did not take place. No significant difference is observed between drain and gate leakage currents of irradiated JFETs. This strongly indicates that defects as leakage paths were introduced into not bulk region but the interface between bulk and the passivation layer of SiO2. While, the transfer characteristics including threshold voltage and transconductance were slightly changed compared with the pristine sample. After drain voltage (VD) was abruptly applied to 6 V, ID at VG= 0 V increased slowly as a function of time. This indicates that variation of transfer characteristics is attributed to capture and emission process at defects generated in channel region.International Conference on Silicon Carbide and Related Materials (ICSCRM2019

Electrical characteristics of gamma-ray irradiated 4H-SiC JFETs

Silicon carbide (SiC) devices are promising as radiation tolerant electronics, since trap generation and charge accumulation by irradiation are suppressed compared with Si devices. However, negative shift of threshold voltage (Vth) of SiC metal-oxide-semiconductor (MOSFET), which is caused by accumulation of holes (positive charges) generated in the gate dielectric (SiO2) by irradiation is a common problem for practical application. SiC junction field effect transistor (JFET), whose gate region is composed of p-n junction is expected to show no negative shift of Vth, while radiation response of SiC JFETs is still unclear. In this study, n-channel depletion mode JFET with nominal channel length and width, and gate length are 2.2 and 0.6, and 18 m (fabricated by AIST ) were irradiated with gamma-rays up to 2.2 MGy at room temperature in nitrogen atmosphere. With increasing dose, Vth gradually shift toward positive voltage side by approximately 1 V. Theoretical expression of JFET suggest that positive shift of Vth is attributed to decrease of carrier density by defects formed in channel region.第3回生体医歯光学共同研究拠点国際シンポジウム参加の