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To investigate a Middle East respiratory syndrome coronavirus (MERS-CoV) outbreak event involving multiple healthcare facilities in Riyadh, Saudi Arabia; to characterize transmission; and to explore infection control implications.
Cases presented in 4 healthcare facilities in Riyadh, Saudi Arabia: a tertiary-care hospital, a specialty pulmonary hospital, an outpatient clinic, and an outpatient dialysis unit.
Contact tracing and testing were performed following reports of cases at 2 hospitals. Laboratory results were confirmed by real-time reverse transcription polymerase chain reaction (rRT-PCR) and/or genome sequencing. We assessed exposures and determined seropositivity among available healthcare personnel (HCP) cases and HCP contacts of cases.
In total, 48 cases were identified, involving patients, HCP, and family members across 2 hospitals, an outpatient clinic, and a dialysis clinic. At each hospital, transmission was linked to a unique index case. Moreover, 4 cases were associated with superspreading events (any interaction where a case patient transmitted to ≥5 subsequent case patients). All 4 of these patients were severely ill, were initially not recognized as MERS-CoV cases, and subsequently died. Genomic sequences clustered separately, suggesting 2 distinct outbreaks. Overall, 4 (24%) of 17 HCP cases and 3 (3%) of 114 HCP contacts of cases were seropositive.
We describe 2 distinct healthcare-associated outbreaks, each initiated by a unique index case and characterized by multiple superspreading events. Delays in recognition and in subsequent implementation of control measures contributed to secondary transmission. Prompt contact tracing, repeated testing, HCP furloughing, and implementation of recommended transmission-based precautions for suspected cases ultimately halted transmission.
A new acoustic positioning method for Autonomous Underwater Vehicles (AUV) that uses a single underwater hydrophone is proposed in this paper to solve problems of Long Baseline (LBL) array laying and communication synchronisation problems among all hydrophones in the traditional method. The proposed system comprises a Strapdown Inertial Navigation System (SINS), a single hydrophone installed at the bottom of the AUV and a single underwater sound source that emits signals periodically. A matrix of several virtual hydrophones is formed with the movement of the AUV. In every virtual LBL window, the time difference from the transmitted sound source to each virtual hydrophone is obtained by means of a Smooth Coherent Transformation (SCOT) weighting cross-correlation in the frequency domain. Then, the recent location of the AUV can be calculated. Simulation results indicate that the proposed method can effectively compensate for the position error of SINS. Thus, the positioning accuracy can be confined to 2 m, and the method achieves good applicability. Compared with traditional underwater acoustic positioning systems, the proposed method can provide great convenience in engineering implementation and can reduce costs.
A fully discrete A-ϕ finite element scheme for a nonlinear model of type-II superconductors is proposed and analyzed. The nonlinearity is due to a field dependent conductivity with the regularized power-law form. The challenge of this model is the error estimate for the nonlinear term under the time derivative. Applying the backward Euler method in time discretisation, the well-posedness of the approximation problem is given based on the theory of monotone operators. The fully discrete system is derived by standard finite element method. The error estimate is suboptimal in time and space.
We analyze in this paper the pressure splitting scheme of a partitioned semi-implicit coupling algorithm for fluid-structure interaction (FSI) simulation. The semi-implicit coupling algorithm is developed on the ground of the artificial compressibility characteristic-based split (AC-CBS) scheme that serves not only for the fluid subsystem but also for the global FSI system. As the dual-time stepping procedure recommended for quasi-incompressible flows is incorporated into the implicit coupling stage, the fluctuating pressure may be unusually susceptible to the AC coefficient. Moreover, it is not trivial to devise an optimal AC formulation for pressure estimation. Instead, we consider a stabilized second-order pressure splitting scheme in the AC-CBS-based partitioned semi-implicit coupling algorithm. Computer simulation of a benchmark FSI experiment demonstrates that good agreement is exposed between the available and present data.
In this paper we present a fully discrete A-ø finite element method to solve Maxwell’s
equations with a nonlinear degenerate boundary condition, which represents a
generalization of the classical Silver-Müller condition for a
non-perfect conductor. The relationship between the normal components of the
electric field E and the magnetic field H obeys a power-law nonlinearity of the type H x n = n x (|E x n|α-1E x n) with α ∈ (0,1]. We prove the existence and
uniqueness of the solutions of the proposed A-ø scheme and derive the error estimates. Finally, we
present some numerical experiments to verify the theoretical result.
Gradual fault detection is always an important issue in integrated navigation systems, and the gradual fault is the most difficult fault to detect. To detect gradual faults in a timely and precise manner in integrated navigation systems, the statistical concepts of the normalised residual mean and the sum of absolute residuals are introduced according to the characteristics of gradual system failure in this paper. The applicability of the improved residual χ2 detection method is discussed. Then, the gradual fault detection program based on the improved residual χ2 detection method is designed with the criterion of normalised residual mean and the sum of absolute residual. The simulation results and vehicle tests show that: 1) The residual of the failed sub-system can be calculated accurately with the improved residual χ2 detection method, which has strong applicability in gradual fault detection; 2) The gradual fault can be detected in a short time by using the normalised residual mean and the sum of absolute residual.
This study was designed to determine the effect of melatonin on the in vitro maturation (IVM) and developmental potential of bovine oocytes denuded of the cumulus oophorus (DOs). DOs were cultured alone (DOs) or with 10−9 M melatonin (DOs + MT), cumulus–oocyte complexes (COCs) were cultured without melatonin as the control. After IVM, meiosis II (MII) rates of DOs, and reactive oxygen species (ROS) levels, apoptotic rates and parthenogenetic blastocyst rates of MII oocytes were determined. The relative expression of ATP synthase F0 Subunit 6 and 8 (ATP6 and ATP8), bone morphogenetic protein 15 (BMP-15) and growth differentiation factor 9 (GDF-9) mRNA in MII oocytes and IFN-tau (IFN-τ), Na+/K+-ATPase, catenin-beta like 1 (CTNNBL1) and AQP3 mRNA in parthenogenetic blastocysts were quantified using real-time polymerase chain reaction (PCR). The results showed that: (1) melatonin significantly increased the MII rate of DOs (65.67 ± 3.59 % vs. 82.29 ± 3.92%; P < 0.05), decreased the ROS level (4.83 ± 0.42 counts per second (c.p.s) vs. 3.78 ± 0.29 c.p.s; P < 0.05) and apoptotic rate (36.99 ± 3.62 % vs. 21.88 ± 2.08 %; P < 0.05) and moderated the reduction of relative mRNA levels of ATP6, ATP8, BMP-15 and GDF-9 caused by oocyte denudation; (2) melatonin significantly increased the developmental rate (24.17 ± 3.54 % vs. 35.26 ± 4.87%; P < 0.05), and expression levels of IFN-τ, Na+/K+-ATPase, CTNNBL1 and AQP3 mRNA of blastocyst. These results indicated that melatonin significantly improved the IVM quality of DOs, leading to an increased parthenogenetic blastocyst formation rate and quality.
A simple one-pot hydrothermal approach that allowed the selective synthesis of complex ZnO architectures with varying configurations without using any surfactants and/or solid templates is proposed in this paper. The ZnO configurations include spherical aggregates, nanosheet-based flowers, microrod-composed flowers, and nanopetal-built flowers. Kinetic factors (i.e., the base type and base/Zn2+ molar ratio) can be easily utilized to control the oriented attachment and growth of [Zn(OH)]2− on the (001) polar planes, thereby regulating the morphology of ZnO architectures. The ZnO architectures were characterized by scanning electron microscopy, transmission electron microscopy, selected-area electron diffraction, x-ray diffraction, and specific surface area. The relationships between the structures and microwave electromagnetic properties were established. Enhanced dielectric and absorption properties were exhibited by ZnO flowers composed of large-aspect-ratio microrods. Such properties could be attributed to the improved microcurrent attenuation and interface scattering rather than the dielectric relaxation and microantenna radiation. This study provides a guide for creating and synthesizing highly efficient microwave absorbing materials.
In this paper, we focus on the unknown environments without artificial landmarks and features, such as disaster situations and polar regions. An approach to active exploration based on an on-line scheme for autonomous allocation of landmarks is proposed. Specifically, the robot carries along with itself some landmarks which are to be allocated during the exploration according to some heuristic rules. The utility of landmark allocation is analyzed and calculated. Then the active exploration is converted into a problem of multi-objective optimization. The objective function includes three weighted terms: the accuracy of localization and mapping, the coverage rate of the unknown environment and the utility of the allocated landmarks. By solving this optimization problem, control inputs of the robot are computed to guarantee that accurate localization, high-quality mapping and complete exploration can be achieved simultaneously. Moreover, supplementation and redundancy elimination of the allocated landmarks are executed to make a complete and non-redundant coverage for the environment. Finally, some landmarks, together with a device for allocating these landmarks, are developed. Both experiment and simulation results are presented to demonstrate the effectiveness of the proposed approach.
The objective of this retrospective study was to determine an optimal time point for vitrification of cleavage-stage human embryos. This study included patients who were undergoing day 2 or day 3 vitrified–warmed cleavage-stage embryo transfer at the In Vitro Fertilization (IVF) Programme of the Shanghai First Maternity and Infant Hospital, China, affiliated to the Tongji University School of Medicine, from April 2010 to March 2012. Intervention was made for the entire cohort of vitrified embryos for poor responder patients so as to avoid severe ovarian hyperstimulation syndrome. Embryo survival rate (SR) after vitrification–warming, implantation rate (IR), and clinical pregnancy rate (CPR) were the main outcome measurements. In total, 380 vitrified–warmed cleavage-stage embryo transfer (VWT) cycles were included. We found that the SR after vitrification and warming for day 2 embryos and day 3 embryos were 92.7% and 92.8%, respectively. For poor ovarian responders, the IR of day 2 and day 3 vitrified–warmed embryos was 6.4% and 13.2%, respectively (P = 0.186). The CPR for day 3 vitrified–warmed embryos was significantly higher than that of day 2 vitrified–warmed embryos (17.6 vs. 4.0 % per transfer cycle, P = 0.036). For patients who had their entire cohort of embryos vitrified to prevent severe ovarian hyperstimulation syndrome (OHSS), the IR and CPR were not significantly different for day 2 and day 3 vitrified–warmed embryo transfer. In conclusion, for vitrified–warmed embryo transfer, cryopreservation of the entire cohort of embryos on day 3 resulted in better clinical outcomes compared with cryopreservation on day 2. Therefore, it is highly recommended that cleavage-stage embryos should be vitrified on day 3, but not on day 2, particularly for poor ovarian responder patients.
In this paper, we study global weak solutions for elastic equations with damping using the compensated compactness method. When the two end states at ± ∞ are not equal, the selfsimilar solutions for the corresponding parabolic equation are used to get the entropic estimates for both the L∞ and L2 cases.
This paper presents an approach for decoding the pressure information exerted over a piece of fabric by means of resistive sensing. The proposed sensor includes a distributed resistive grids constructed by two systems of orthogonally contacted electrical conductive yarns, with no external sensing element to be attached on the fabric. Since the conductive yarns serve as the sensing and wiring elements simultaneously, this design simplifies the fabrication process, reduces the cost and makes the production of large area flexible pressure sensor possible. The location of the pressure applied on the fabric can be identified by detecting the position where the change of the resistances occurs between two embroidered yarns. Meanwhile, the magnitude of the pressure can be acquired by measuring the variations of the resistance. In order to eliminate the “crosstalk” effect between adjoining fibers, the yarns were separately wired on the fabric surface.
An experimental investigation was carried out to study the crack initiation and growth in a single-edge notched NiTi shape memory alloy sheet under tension. It is observed that a crack initiated at the tip of a V-shape notch before the peak axial load was reached and it grew steadily across the width of the NiTi sheet until final fracture. In-plane crack-tip deformation fields at various stages of the crack growth were measured based on an image correlation technique and the crack-tip opening displacement (CTOD) and crack-tip opening angle (CTOA) were subsequently determined. The fracture surface of the NiTi sheet was dimpled based on scanning electron microscopy examinations.
It is well known that c-Jun N-terminal kinase (JNK) plays pivotal roles in various mitotic events, but its function in mammalian oocyte meiosis remains unknown. In this study, we found that no specific JNK2 signal was detected in germinal vesicle stage. JNK2 was associated with the spindles especially the spindle poles and cytoplasmic microtubule organizing centers at prometaphase I, metaphase I, and metaphase II stages. JNK2 became diffusely distributed and associated with the midbody at telophase I stage. Injection of myc-tagged JNK2α1 mRNA into oocytes also revealed its localization on spindle poles. The association of JNK2 with spindle poles was further confirmed by colocalization with the centrosomal proteins, γ-tubulin and Plk1. Nocodazole treatment showed that JNK2 may interact with Plk1 to regulate the spindle assembly. Then we investigated the possible function of JNK2 by JNK2 antibody microinjection and JNK specific inhibitor SP600125 treatment. These two manipulations caused abnormal spindle formation and decreased the rate of first polar body (PB1) extrusion. In addition, inhibition of JNK2 resulted in impaired localization of Plk1. Taken together, our results suggest that JNK2 plays an important role in spindle assembly and PB1 extrusion during mouse oocyte meiotic maturation.
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