Studies on Hospital infection of methicillin-resistant Staphylococcus aureus

医院感染的重要病原菌—— 耐甲氧西林金黄色葡萄球菌（methicillin resistant staphylococcus aureus，MRSA） 被称之谓超级细菌（superbug）或沉默的杀手（sillent killer），是临床治疗非常棘手的一大难题和研究热点。笔者概述了MRSA医院感染的历史及现状，及其生物学特性、耐药机制、实验室检测与分型。MRSA医院感染的预防和治疗。Resistant Staphylococcus aureus MRSA (methicillin), an important pathogen of nosocomial infection, is called superbug sillent (killer), which is a very difficult problem in clinical treatment. In this paper, the history and present situation of MRSA hospital infection, and its biological characteristics, drug resistance mechanism, laboratory test and classification were summarized. Prevention and treatment of nosocomial infection in MRSA were introduced.

7-Benzyl-3-(4-chloro­phen­yl)-2-isobutyl­amino-5,6,7,8-tetra­hydro­pyrido[4′,3′:4,5]thieno[2,3-d]pyrimidin-4(3H)-one

In the title compound, C26H27ClN4OS, the thienopyrimidine fused-ring system is close to coplanar (r.m.s. deviation = 0.0089 Å), with a maximum deviation of 0.0283 (17) Å for the N atom adjacent to the benzene ring. This ring system forms dihedral angles of 83.51 (3) and 88.20 (5)° with the adjacent benzyl and phenyl rings, respectively. In the crystal, N—H⋯Cl inter­actions and C—H⋯O hydrogen bonds are observed

Numerical simulation of fluid flow and heat transfer in a curved square duct by using the Lattice Boltzmann method

The study of viscous flow in curved ducts is of fundamental interest in fluid mechanics due to the numerous applications such as flows through turbomachinery blade passages, aircraft intakes, diffusers, heat exchangers, and so on [1–6]. The major effect of curved ducts on the fluid flow involves the strong secondary flow due to the longitudinal curvature in the geometry [7–9]. The presence of longitudinal curvature generates centrifugal force (which is perpendicular to the main flow along the axis) and produces so-called secondary flow on the cross sections of ducts

Significant Phonon Drag Effect in Wide Bandgap GaN and AlN

A thorough understanding of electrical and thermal transport properties of group-III nitride semiconductors is essential for their electronic and thermoelectric applications. Despite extensive previous studies, these transport properties were typically calculated without considering the nonequilibrium coupling effect between electrons and phonons, which can be particularly strong in group-III nitride semiconductors due to the high electric fields and high heat currents in devices based on them. In this work, we systematically examine the phonon drag effect, namely the momentum exchange between nonequilibrium phonons and electrons, and its impact on charge mobility and Seebeck coefficient in GaN and AlN by solving the fully coupled electron and phonon Boltzmann transport equations with ab initio scattering parameters. We find that, even at room temperature, the phonon drag effect can significantly enhance mobility and Seebeck coefficient in GaN and AlN, especially at higher carrier concentrations. Furthermore, we show that the phonon drag contribution to mobility and Seebeck coefficient scale differently with the carrier concentration and we highlight a surprisingly important contribution to the mobility enhancement from the polar optical phonons. We attribute both findings to the distinct mechanisms the phonon drag affects mobility and Seebeck coefficient. Our study advances the understanding of the strong phonon drag effect on carrier transport in wide bandgap GaN and AlN and gives new insights into the nature of coupled electron-phonon transport in polar semiconductors

Wireless body area network mobility-aware task offloading scheme

The increasing amount of user equipment (UE) and the rapid advances in wireless body area networks bring revolutionary changes in healthcare systems. However, due to the strict requirements on size, reliability and battery lifetime of UE devices, it is difficult for them to execute latency sensitive or computation intensive tasks effectively. In this paper, we aim to enhance the UE computation capacity by utilizing small size coordinator-based mobile edge computing (C-MEC) servers. In this way, the system complexity, computation resources, and energy consumption are considerably transferred from the UE to the C-MEC, which is a practical approach since C-MEC is power charged, in contrast to the UE. First, the system architecture and the mobility model are presented. Second, several transmission mechanisms are analyzed along with the proposed mobility-aware cooperative task offloading scheme. Numerous selected performance metrics are investigated regarding the number of executed tasks, the percentage of failed tasks, average service time, and the energy consumption of each MEC. The results validate the advantage of task offloading schemes compared with the traditional relay-based technique regarding the number of executed tasks. Moreover, one can obtain that the proposed scheme archives noteworthy benefits, such as low latency and efficiently balance the energy consumption of C-MECs

Extending low energy effective field theory with a complete set of dimension-7 operators

We present a complete and independent set of dimension-7 operators in the low energy effective field theory (LEFT) where the dynamical degrees of freedom are the standard model five quarks and all of the neutral and charged leptons. All operators are non-Hermitian and are classified according to their baryon ($\Delta B$) and lepton ($\Delta L$) numbers violated. Including Hermitian-conjugated operators, there are in total $3168$, $750$, $588$, $712$ operators with $(\Delta B,\Delta L)=(0,0)$, $(0,\pm 2)$, $(\pm 1,\mp 1)$, $(\pm 1,\pm 1)$ respectively. We perform the tree-level matching with the standard model effective field theory (SMEFT) up to dimension-7 (dim-7) operators in both LEFT and SMEFT. As a phenomenological application we study the effective neutrino-photon interactions due to dim-7 lepton number violating operators that are induced and much enhanced at one loop from dim-6 operators that in turn are matched from dim-7 SMEFT operators. We compare the cross sections of various neutrino-photon scattering with their counterparts in the standard model and highlight the new features. Finally we illustrate how these effective interactions could arise from ultraviolet completion.Comment: 16 pages, 3 figure