Since December 2019, when coronavirus disease 2019 (Covid-19) emerged in Wuhan city and rapidly spread throughout China, data have been needed on the clinical characteristics of the affected ...patients.
We extracted data regarding 1099 patients with laboratory-confirmed Covid-19 from 552 hospitals in 30 provinces, autonomous regions, and municipalities in mainland China through January 29, 2020. The primary composite end point was admission to an intensive care unit (ICU), the use of mechanical ventilation, or death.
The median age of the patients was 47 years; 41.9% of the patients were female. The primary composite end point occurred in 67 patients (6.1%), including 5.0% who were admitted to the ICU, 2.3% who underwent invasive mechanical ventilation, and 1.4% who died. Only 1.9% of the patients had a history of direct contact with wildlife. Among nonresidents of Wuhan, 72.3% had contact with residents of Wuhan, including 31.3% who had visited the city. The most common symptoms were fever (43.8% on admission and 88.7% during hospitalization) and cough (67.8%). Diarrhea was uncommon (3.8%). The median incubation period was 4 days (interquartile range, 2 to 7). On admission, ground-glass opacity was the most common radiologic finding on chest computed tomography (CT) (56.4%). No radiographic or CT abnormality was found in 157 of 877 patients (17.9%) with nonsevere disease and in 5 of 173 patients (2.9%) with severe disease. Lymphocytopenia was present in 83.2% of the patients on admission.
During the first 2 months of the current outbreak, Covid-19 spread rapidly throughout China and caused varying degrees of illness. Patients often presented without fever, and many did not have abnormal radiologic findings. (Funded by the National Health Commission of China and others.).
Currently, investigations on the microbiota of sports centers and related facilities have been carried out in some countries, which showed that Microsporum gypseum, Trichophyton mentagrophytes and T. ...tonsurans are important dermatoprotofungi. In China, some research on athletes and sports equipment between the fungal community and public health has made some interesting achievements. However, the bacterial group among them has not been reported. Therefore, The aim of this study was to uncover (I) gymnastic equipment is there potential pathogenic factors and (ii) is there any difference in the biomarker of bacterial in different types of gymnastic room? The samples were collected from the gymnastics halls of one university in western China and main sports equipment, including gymnastics carpets, moving barres, hoops and balls, as well as wall bars, parallel bars and horizontal bars. The 16S rDNA of all the samples was sequenced, and the analyses were performed using FaproTax, Bug base function prediction and Line Discriminant Analysis (LDA) Effect Size. A 16S rDNA sequence analysis revealed abundant bacterial species biodiversity on gymnasts and apparatuses from two gymnastics halls at a university in western China. An analysis using the FaproTax and Bugbase functional prediction platforms showed that there were some opportunistic pathogens on the athletes and equipment from the Rhythmic Gymnastics (RG) and Artistic Gymnastics (AG) halls, such as Staphylococcus and Corynebacteiaceae. Infectious agents associated with cancer induction and development, such as Ruminococcaceae, Veillonellaceae and Moraxellaceae, as well as microbial toxin producers with a potential impact on human health, were also detected. According to a line discriminant analysis (LDA effect size), the bacterial biomarker groups of the two gymnasiums were different at the phylum-genus level: for RG, Erysipelatoclostridium, Lachnospiraceae and Bacteroidales, while for AG, Rhizobiales. Based on the results of the investigation, we suggest that more comprehensive consideration should be given to indoor microbial biodiversity and related public health problems in school gymnasiums.
We investigate the shift current bulk photovoltaic response of materials close to a band inversion topological phase transition. We find that the bulk photocurrent reverses direction across the band ...inversion transition, and that its magnitude is enhanced in the vicinity of the phase transition. These results are demonstrated with first principles density functional theory calculations of BiTeI and CsPbI_{3} under hydrostatic pressure, and explained with an analytical model, suggesting that this phenomenon remains robust across disparate material systems.
This study depicts the influence of the Rashba effect on the band-edge exciton processes in all-inorganic CsPbBr3 perovskite single colloidal nanocrystal (NC). The study is based on magneto-optical ...measurements carried out at cryogenic temperatures under various magnetic field strengths in which discrete excitonic transitions were detected by linearly and circularly polarized measurements. Interestingly, the experiments show a nonlinear energy splitting between polarized transitions versus magnetic field strength, indicating a crossover between a Rashba effect (at the lowest fields) to a Zeeman effect at fields above 4 T. We postulate that the Rashba effect emanates from a lattice distortion induced by the Cs+ motion degree of freedom or due to a surface effect in nanoscale NCs. The unusual magneto-optical properties shown here underscore the importance of the Rashba effect in the implementation of such perovskite materials in various optical and spin-based devices.
Hybrid lead-halide perovskites have emerged as an excellent class of photovoltaic materials. Recent reports suggest that the organic molecular cation is responsible for local polar fluctuations that ...inhibit carrier recombination. We combine low-frequency Raman scattering with first-principles molecular dynamics (MD) to study the fundamental nature of these local polar fluctuations. Our observations of a strong central peak in the cubic phase of both hybrid (CH_{3}NH_{3}PbBr_{3}) and all-inorganic (CsPbBr_{3}) lead-halide perovskites show that anharmonic, local polar fluctuations are intrinsic to the general lead-halide perovskite structure, and not unique to the dipolar organic cation. MD simulations indicate that head-to-head Cs motion coupled to Br face expansion, occurring on a few hundred femtosecond time scale, drives the local polar fluctuations in CsPbBr_{3}.
Ferroelectricity and band topology are two extensively studied yet distinct properties of insulators. Nonetheless, their coexistence has never been observed in a single material. Using ...first-principles calculations, we demonstrate that a noncentrosymmetric perovskite structure of CsPbI3 allows for the simultaneous presence of ferroelectric and topological orders with appropriate strain engineering. Metallic topological surface states create an intrinsic short-circuit condition, helping stabilize bulk polarization. Exploring diverse structural phases of CsPbI3 under pressure, we identify that the key structural feature for achieving a ferroelectric topological insulator is to suppress PbI6 cage rotation in the perovskite structure, which could be obtained via strain engineering. Ferroelectric control over the density of topological surface states provides a new paradigm for device engineering, such as perfect-focusing Veselago lens and spin-selective electron collimator. Our results suggest that CsPbI3 is a simple model system for ferroelectric topological insulators, enabling future studies exploring the interplay between conventional symmetry-breaking and topological orders and their novel applications in electronics and spintronics.
This randomized, double‐blind, placebo‐controlled study evaluated whether lamivudine given during late pregnancy can reduce hepatitis B virus (HBV) perinatal transmission in highly viraemic mothers. ...Mothers were randomized to either lamivudine 100 mg or placebo from week 32 of gestation to week 4 postpartum. At birth, infants received recombinant HBV vaccine with or without HBIg and were followed until week 52. One hundred and fifty mothers, with a gestational age of 26–30 weeks and serum HBV DNA >1000 MEq/mL (bDNA assay), were treated. A total of 141 infants received immunoprophylaxis at birth. In lamivudine‐treated mothers, 56 infants received vaccine + HBIg (lamivudine + vaccine + HBIg) and 26 infants received vaccine (lamivudine + vaccine). In placebo‐treated mothers, 59 infants received vaccine + HBIg (placebo + vaccine + HBIg). At week 52, in the primary analyses where missing data was counted as failures, infants in the lamivudine + vaccine + HBIg group had a significant decrease in incidence of HBsAg seropositivity (10/56, 18%vs 23/59, 39%; P = 0.014) and in detectable HBV DNA (11/56, 20%vs 27/59, 46%; P = 0.003) compared to infants in the placebo + vaccine + HBIg group. Sensitivity analyses to evaluate the impact of missing data at week 52 resulting from a high dropout rate (13% in the lamivudine + vaccine + HBIg group and 31% in the placebo + vaccine + HBIg group) remained consistent with the primary analysis in that lower transmission rates were still observed in the infants of lamivudine‐treated mothers, but the differences were not statistically significant. No safety concerns were noted in the lamivudine‐treated mothers or their infants. Results of this study suggest that lamivudine reduced HBV transmission from highly viraemic mothers to their infants who received passive/active immunization.
Two-dimensional (2D) organic-inorganic hybrid perovskites have been intensively explored in recent years due to their tunable band gaps and exciton binding energies and increased stability with ...respect to three-dimensional (3D) hybrid perovskites. Experimental observations suggest the existence of localized edge states in 2D hybrid perovskites which facilitate extremely efficient electron-hole dissociation and long carrier lifetimes, while multiple origins for their formation have been proposed. Using first-principles calculations, we demonstrate that layer edge states are stabilized by internal electric fields created by polarized molecular alignment of organic cations in 2D hybrid perovskites when they are two layers or thicker. Our study gives a simple physical explanation of the edge state formation, and facilitating the design and manipulation of layer edge states for optoelectronic applications.
PDF
