High Prevalence of Extended-Spectrum Beta Lactamases among Salmonella enterica Typhimurium Isolates from Pediatric Patients with Diarrhea in China

We investigated the extended-spectrum beta lactamases among 62 Salmonella enterica Typhimurium isolates recovered from children with diarrhea in a Chinese pediatric hospital. A large proportion of S. enterica Typhimurium isolates were resistant to multiple antimicrobial agents, including ampicillin (90.3%), tetracycline (80.6%), trimethoprim/sulfamethoxazole (74.2%), chloramphenicol (66.1%), cefotaxime (27.4%). Forty-nine (79.0%) of S. enterica Typhimurium isolates were positive for blaTEM-1b and resistant to ampicillin. Thirteen S. enterica Typhimurium isolates (21.0%) were positive for blaCTX-M-1-group and blaCTX-M-9-group, and all isolates harboring blaCTX-M genes were positive for ISEcp1. Two main clones (PFGE type A and D) accounted for nearly 70% of S. enterica Typhimurium isolates, and 7 CTX-M-producing isolates belonged to PFGE type D. Collectively, our data reveal multi-drug resistance and a high prevalence of extended spectrum beta lactamases among S. enterica Typhimurium isolates from children in China. In addition, we report the first identification of blaCTX-M-55 within Salmonella spp. Our data also suggest that clonal spread is responsible for the dissemination of S. enterica Typhimurium isolates

A Two-dimensional analysis of surface acoustic waves in finite plates with eigensolutions

It is generally known that surface acoustic waves, or Rayleigh waves, have different mode shapes in infinite plates. To be precise, there are both exponentially decaying and growing components in plates appearing in pairs, representing symmetric and anti-symmetric modes in a plate. As the plate thickness increases, the combined modes will approach to the Rayleigh mode in a semi-infinite solid, exhibiting surface acoustic wave deformation and velocity. As a result, for plates with finite thickness, we need to consider the effect of two modes in the analysis. ... In this study, the two-dimensional theory for surface acoustic waves in finite plates is extended to include exponentially growing modes in the expansion function, creating a twodimensional equation system for plates with finite thickness. Since additional expansion functions are also exponential, the two-dimensional equations keep the same appearance, implying the same evaluation and solution procedure. These results are important in the improvement of two-dimensional analysis of surface acoustic waves in finite solids, which are the essential problem in surface acoustic wave resonator analysis and design

The Chinese stock dividend puzzle

In this paper, we examine the announcement effects of dividends with an emphasis on stock dividends in China's capital market. We find that dividend-paying stocks exhibit significantly positive abnormal returns while non-dividend-paying stocks show a negative announcement effect. Further, we document that the cumulative abnormal returns for pure stock dividends and combined dividends are the main drivers of this announcement effect. In contrast, pure cash dividend stocks experience no significant price run-up before announcement. The significant announcement effect of stock dividends is robust to controlling the earnings surprise effect. We offer some discussion of the possible explanations

Variation of the Relative Soil Moisture of Farmland in a Continental River Basin in China

The reduction of grain production caused by drought is one of the most serious problems caused by natural disasters. The relative soil moisture of farmland is the most important monitoring indicator for agricultural drought. This study investigated the relative soil moisture of farmland data from 38 agrometeorological stations in a continental river basin area in China from 1992 to 2012. Spatial and temporal variations of the relative soil moisture of farmland were studied using geostatistical analysis. The results show that, from 1992 to 2012, the average annual relative soil moisture of farmland in the continental river basin ranged from 62.5 to 86.1%, and the relative soil moisture of farmland was high in the marginal areas of basins and low in the central areas of basins and plateau areas. The relative soil moisture of farmland was high in the Tarim Basin and the Hexi Corridor, which are located in the northern Tianshan Mountains and the southern and northern Qilian Mountains, and was low from the northern Altun Mountains to the south of Lop Nor, the Turpan Depression, and the Tarbagatai Mountains. From 1992 to 2012, the annual average relative soil moisture of farmland in the continental river basins showed an increasing trend, with a growth rate of 0.57% yr−1. The variation tendency of the relative soil moisture of farmland was different in different river basins; the relative soil moisture showed a decreasing trend in the Mongolian Plateau and an increasing trend in other basin areas. The relative soil moisture of farmland increased in summer, spring, and winter, and decreased in autumn. The change in relative soil moisture of farmland was due to a combination of climatic factors, such as precipitation and temperature, as well as topography and glacial meltwater

Real-Time Relative Positioning Study of an Underwater Bionic Manta Ray Vehicle Based on Improved YOLOx

Compared to traditional vehicles, the underwater bionic manta ray vehicle (UBMRV) is highly maneuverable, has strong concealment, and is an emerging research field in underwater vehicles. Based on the completion of the single-body research, it is crucial to research the swarm of UBMRVs for the implementation of complex tasks, such as large-scale underwater detection. The relative positioning capability of the UBMRV is the key to realizing a swarm, especially when underwater acoustic communications are delayed. To solve the real-time relative positioning problem between individuals in the UBMRV swarm, this study proposes a relative positioning method based on the combination of the improved object detection algorithm and binocular distance measurement. To increase the precision of underwater object detection in small samples, this paper improves the original YOLOx algorithm. It increases the network’s interest in the object area by adding an attention mechanism module to the network model, thereby improving its detection accuracy. Further, the output of the object detection result is used as the input of the binocular distance measurement module. We use the ORB algorithm to extract and match features in the object-bounding box and obtain the disparity of the features. The relative distance and bearing information of the target are output and shown on the image. We conducted pool experiments to verify the proposed algorithm on the UBMRV platform, proved the method’s feasibility, and analyzed the results

A Near-Infrared Triggered Nanophotosensitizer Inducing Domino Effect on Mitochondrial Reactive Oxygen Species Burst for Cancer Therapy

Photodynamic therapy (PDT) is a well-established modality for cancer therapy, which locally kills cancer cells when light irradiates a photosensitizer. However, conventional PDT is often limited by the extremely short lifespan and severely limited diffusion distance of reactive oxygen species (ROS) generated by photosensitizer, as well as the penetration depth of visible light activation. Here, we develop a near-infrared (NIR) triggered nanophotosensitizer based on mitochondria targeted titanium dioxide-coated upconversion nanoparticles for PDT against cancer. When irradiated by NIR laser, the nanophotosensitizer could produce ROS in mitochondria, which induced the domino effect on ROS burst. The overproduced ROS accumulated in mitochondria, resulting in mitochondrial collapse and irreversible cell apoptosis. Confocal fluorescence imaging indicated that the mitochondrial targeting and real-time imaging of ROS burst could be achieved in living cells. The complete removal of tumor <i>in vivo</i> confirmed the excellent therapeutic effect of the nanophotosensitizer

Additional file 1 of DhuFAP: a platform for gene functional analysis in Dendrobium huoshanense

Supplementary Material