Xiaohui Sun

Lithium/sulfur cells have attracted much attention due to their higher theoretical specific capacity and energy compared to those of current lithium-ion cells. However, the application of Li/S cells is still hampered by short cycle life. Sulfur-graphene oxide nanocomposites have shown promise as cathode materials for long-life Li/S cells because oxygen-containing functional groups on the surface of graphene oxide were successfully used as sulfur immobilizers by forming weak bonds with sulfur and polysulfides. While S-GO showed much improved cycling performance, the capacity decay still needs to be improved for commercially viable cells. In this study, we attempt to understand the capacity fading mechanism based on an ex situ study of the structural and chemical evolution of S-GO nanocomposite cathodes with various numbers of cycles using scanning electron microscopy, near edge X-ray absorption fine structure and X-ray photoelectron spectroscopy. It is found that both the surface morphologies and chemical structures of the cathode materials change considerably with increasing number of cycles. These changes are attributed to several unexpected chemical reactions of lithium with S-GO nanocomposites occurring during the discharge-charge processes with the formation of Li2CO3, Li2SO3, Li 2SO4, and COSO2Li species. These reactions result in the loss of recyclable active sulfur on the surface of the electrode, and thus capacity fades while coulombic efficiency is near 100%. Moreover, the reaction products accumulate on the cathode surface, forming a compact blocking insulating layer which may make the diffusion of Li ions into/out of the cathode difficult during the discharge-charge process and thus lead to lower utilization of sulfur at higher rates. We think that these two observations are significant contributors to the capacity and rate capability degradation of the Li/S-GO cells. Therefore, for the rechargeable Li/S-GO cells, we suggest that the content of oxygen-containing functional groups on GO should be optimized and more stable functional groups need to be identified for further improvement of the cycling performance. The information we gain from this study may provide general insights into the fundamental understanding of the degradation mechanisms of other rechargeable Li/S cells using similar oxygen-containing functional groups as sulfur immobilizers. © the Partner Organisations 2014.

We report the design and characterization of a CMOS pixel direct charge sensor, Topmetal-II-, fabricated in a standard 0.35 μm CMOS Integrated Circuit process. The sensor utilizes exposed metal patches on top of each pixel to directly collect charge. Each pixel contains a low-noise charge-sensitive preamplifier to establish the analog signal and a discriminator with tunable threshold to generate hits. The analog signal from each pixel is accessible through time-shared multiplexing over the entire array. Hits are read out digitally through a column-based priority logic structure. Tests show that the sensor achieved a <15e- analog noise and a 200e- minimum threshold for digital readout per pixel. The sensor is capable of detecting both electrons and ions drifting in gas. These characteristics enable its use as the charge readout device in future Time Projection Chambers without gaseous gain mechanism, which has unique advantages in low background and low rate-density experiments.

BACKGROUND: It has been argued that what differentiates delusional ideation from full-blown delusions (indicating need for care) is not the number of beliefs, but the experiential dimensions such as conviction, distress, and preoccupation. However, how these dimensions evolve over time and affect outcomes is under-researched. While delusional conviction and distress are associated with reasoning biases and worry respectively in clinical samples, how these processes predict trajectories of delusional dimensions in the general population remains unclear. METHOD: Young adults (age 18-30) were screened for delusional ideation on the Peters et al. Delusions Inventory. Participants with at least one delusional ideation were randomly selected for a 4-wave assessment (6-month apart). Trajectories of delusional dimensions were separately identified by latent class growth analyses, then compared on baseline levels of jumping-to-conclusions bias, belief inflexibility, worry, and meta-worry. RESULTS: The longitudinal sample consisted of 356 individuals (drawn from a community sample of 2,187). For each of the three dimensions (conviction, distress, and preoccupation), four-group linear models were identified-high stable, moderate stable, moderate decreasing, and low stable. The high stable group exhibited worse emotional and functional outcomes at 18 months than the other three groups. Worry and meta-worry predicted group differences, and notably differentiated the moderate decreasing groups from the moderate stable groups. Contrary to hypothesis, jumping-to-conclusions bias was milder in the high/moderate stable groups than the low stable group for conviction. CONCLUSIONS: Distinct trajectories of delusional dimensions were predicted by worry and meta-worry. Differences between the decreasing and stable groups carried clinical implications. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

Background Kawasaki disease, the most common cause of acquired heart disease in developed countries, is a self-limited vasculitis that is treated with high doses of intravenous immunoglobulin. Resistance to intravenous immunoglobulin in Kawasaki disease increases the risk of coronary artery aneurysms. We assessed whether the addition of infliximab to standard therapy in acute Kawasaki disease reduces the rate of treatment resistance. Methods We undertook a phase 3, randomised, double-blind, placebo-controlled trial in two children's hospitals in the USA to assess the addition of infliximab to standard therapy. Eligible participants were children aged 4 weeks-17 years who had a fever for 3-10 days and met American Heart Association criteria for Kawasaki disease. Participants were randomly allocated in 1:1 ratio to two treatment groups: infliximab 5 mg/kg at 1 mg/mL intravenously over 2 h or placebo. Randomisation was based on a randomly permuted block design, stratified by age, sex, and centre. Patients, treating physicians and staff, study team members, and echocardiographers were all masked to treament assignment. The primary outcome was the difference between the groups in treatment resistance defined as a temperature of 38·0°C or higher at 36 h to 7 days after completion of the infusion of intravenous immunoglobulin. Analysis was by intention to treat. This trial is registered with ClinicalTrials.gov, NCT00760435. Findings 196 patients were enrolled and randomised: 98 to the infliximab group and 98 to placebo. One patient in the placebo group was withdrawn from the study because of hypotension before receiving treatment. Treatment resistance rate did not differ significantly. Compared with the placebo group, participants given infliximab had fewer days of fever. At week 2, infliximab-treated patients had greater mean reductions in erythrocyte sedimentation rate and a two-fold greater decrease in Z score of the left anterior descending artery than did those in the placebo group, but this difference was not significant at week 5. Participants in the infliximab group had a greater mean reduction in C-reactive protein concentration and in absolute neutrophil count at 24 h after treatment than did those given placebo, but by week 2 this difference was not significant. At week 5, none of the laboratory values differed significantly compared with baseline. No significant differences were recorded between the two groups at any timepoint in proximal right coronary artery Z scores, age-adjusted haemoglobin values, duration of hospital stay, or any other laboratory markers of inflammation measured. No reactions to intravenous immunoglobulin infusion occurred in patients treated with infliximab compared with 13 patients given placebo. No serious adverse events were directly attributable to infliximab infusion. Interpretation The addition of infliximab to primary treatment in acute Kawasaki disease did not reduce treatment resistance. However, it was safe and well tolerated and reduced fever duration, some markers of inflammation, left anterior descending coronary artery Z score, and intravenous immunoglobulin reaction rates. Funding US Food and Drug Administration, Robert Wood Johnson Foundation, and Janssen Biotech.