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To investigate the effect of intensive care unit (ICU) admission model on acute kidney injury (AKI) development and the prognosis in patients with sepsis.Patients with sepsis admitted to the ICU of Xinjiang Uygur Autonomous Region People's Hospital from January 2019 to July 2020 were retrospectively analyzed. According to the ICU admission model, the patients were divided into emergency group (first admission or emergency transfer from relevant surgical departments) and delayed group (transferred from the general ward due to disease evolution). Patients were divided into AKI group and non-AKI group according to whether AKI was accompanied. The gender, age, underlying diseases, surgical history, heart rate, laboratory test indicators, acute physiology and chronic health evaluation II (APACHE II), sequential organ failure assessment (SOFA), organ failure and acute complications were collected. The incidence of AKI, 28-day mortality and length of ICU stay were recorded. Univariate and multivariate Logistic regression was used to analyze the risk factors of AKI in patients with sepsis.A total of 185 patients with sepsis were enrolled, including 96 cases in the emergency group and 89 cases in the delayed group. 119 cases of AKI occurred while 66 cases without AKI development. The incidence of AKI within 7 days and the 28-day mortality of patients in the delayed group were significantly higher than those in the emergency group [AKI incidence rate: 77.53% (69/89) vs. 52.08% (50/96), 28-day mortality: 24.72% (22/89) vs. 10.42% (10/96), both P0.05], and the length of ICU stay was significantly longer than that of the emergency group (days: 18.70±7.29 vs. 14.56±4.75, P0.05). Univariate Logistic analysis showed that there were significant differences in age, diabetes, hypertension, organ failure, heart failure, APACHE II score, SOFA score, white blood cell count (WBC), absolute neutrophil value, platelet count (PLT), blood lactate, total bilirubin, and ICU transferred from general wards between AKI group and non-AKI group. Multivariate Logistic regression analysis showed that transfer from general ward to ICU due to disease evolution was an independent risk factor for AKI in ICU sepsis patients [odds ratio (OR) = 5.165, 95% confidence interval (95%CI) was 3.911-6.823, P0.001].Septic patients transferred from general ward to ICU due to disease evolution are more likely to develop AKI, and also had a higher mortality and longer ICU stay. It may be an independent risk factor for AKI complicated by patients with sepsis in ICU.

This paper presents a novel polarization-reconfigurable antenna based on the combination of circularly polarized (CP) modes, which is capable of changing its polarization states among arbitrary linear polarizations (LPs), left-handed circular polarization (LHCP) and right-handed circular polarization (RHCP). A truncated square patch with two isolated aperture-coupling feeds is used as radiation element operating at 2.45 GHz, which can operate in two orthogonal CP modes with low crosstalk. By exciting one of the two feeding microstrip lines, LHCP or RHCP mode can be independently generated. Meanwhile, by simultaneously exciting the two feeding microstrip lines with identical amplitudes but with different initial phases, LP mode with polarization plane oriented in any desired azimuth direction can be obtained. The simulated and measured peak gain of the proposed antenna remains at about 6.8 dBi at 2.45 GHz and the impedance matching bandwidth ranging from 2.25 to 2.60 GHz is fully overlapped for all the polarization states. Experimental results show a good performance of the proposed antenna.

This paper presents the coupled, and decoupled schemes for the naturally fractured reservoir consists of the triple-porosity medium. More specifically, the triple-porosity medium contains three contagious porous medium with more permeable macrofractures, less permeable microfractures, and matrix region which is often known as dual-fracture-matrix fluid flow model. Since the matrix has fluid communication with less permeable microfractures, and macrofratures are fed by the microfractures only, the global domain is divided into two subdomains by considering the traditional dual-porosity region and more permeable macrofractures region respectively. The flow and mass exchange between less permeable microfractures and more permeable macrofractures are modeled by two-fluid communication interface conditions while no-communication interface condition is imposed on between matrix and macrofractures region. The weak formulation and the well-posedness of the dual-fracture-matrix model are derived. Furthermore, coupled, implicit-explicit and data-passing partitioned schemes are proposed. The stability and the optimal convergence analysis are derived for both decoupled schemes. Five numerical examples are presented to illustrate the accuracy of the numerical methods and the applicability of the dual-fracture-matrix fluid flow model. Moreover, the parameter sensitivity analysis is performed in the fourth numerical example.

This article aims to study the Quasi-least square mixed finite element (FE) method for the approximate solution of Magnato-Hydro-Dynamic equations (MHD). The resulting non-linear system of equations are linearized around a characteristic state, resulting in first order linearized least-square models that yield algebraic system of equations with symmetric positive definite coefficient matrices. A central feature of the method is that it does not require (Ladyzhenskaya-Babuska-Brezzi) LBB conditions on the finite dimensional subspaces and the resulting bilinear form is symmetric and positive definite. Secondly, it only needs to choose the value of a single parameter to find the well-posedness of the model equations. For the theoretical accuracy and authentication of the method, we investigate existence of the solutions and obtain a priori error estimates. The variables are fluid velocity, fluid pressure and magnetic field. Numerical tests are performed in order to assess the stability and the accuracy of the resulting methods. Result shows good agreement with analytical solutions.

Numerical simulation of saltwater intrusion problem has attracted more and more attention in the past decades. Based on parallel subspace correction method proposed by Xu (1992), a new overlapping domain decomposition parallel algorithm is constructed to solve saltwater intrusion problem. In this algorithm, the splitting positive definite mixed element method is used to discrete head water equation, while the characteristic Galerkin finite element method is used to approximate concentration equation. The relation between the convergence rate and discretization parameters, including the overlapping degree of the subspaces, is considered. Furthermore, the convergence of this algorithm is analyzed and the corresponding error estimate is given. The convergence result suggests that only two iterations are needed to reach the given accuracy at each time level.

In this paper, we investigate the heterogeneous multiscale method (HMM) for the optimal control problem governed by the parabolic equation with highly oscillatory coefficients. The state variable and adjoint state variable are approximated by the multiscale discretization scheme that relies on coupled macro and micro finite elements, while the control variable is discretized by the piecewise constants. By applying the well-known Lions’ Lemma to the discretized optimal control problem, we obtain the necessary and sufficient optimality conditions. A priori error estimates are derived for the state, co-state and the control with uniform bounded constants. Finally, numerical results are presented to illustrate our theoretical findings.

We present a space–time fractional Allen–Cahn phase-field model that describes the transport of the fluid mixture of two immiscible fluid phases. The space and time fractional order parameters control the sharpness and the decay behavior of the interface via a seamless transition of the parameters. Although they are shown to provide more accurate description of anomalous diffusion processes and sharper interfaces than traditional integer-order phase-field models do, fractional models yield numerical methods with dense stiffness matrices. Consequently, the resulting numerical schemes have significantly increased computational work and memory requirement. We develop a lossless fast numerical method for the accurate and efficient numerical simulation of the space–time fractional phase-field model. Numerical experiments shows the utility of the fractional phase-field model and the corresponding fast numerical method.