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  • Author: Yang Liu x
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Abstract

This paper is concerned with four-point boundary value problems of the one-dimensional generalized Lane-Emden systems on whole lines. The Green’s functions G(t, s) for the problem (ρ(t)x′(t)) = 0 with boundary conditions limtx(t)kx(ξ)=limt+x(t)lx(η)=0 and limtx(t)kx(ξ)=limt+ρ(t)x(t)lp(η)x(η)=0 are obtained respectively. We proved that G(t, s) ≥ 0 under some assumptions which actually generalize a corresponding result in [J. Math. Anal. Appl. 305 (2005) 253-276]. Sufficient conditions to guarantee the existence of positive solutions of this kind of models are established. Examples are given at the end of the paper.

Abstract

Objective

The aim of this study was to explore whether positive emotion mediates the relationship between job burnout and turnover intentions among Chinese nurses.

Methods

A cross-sectional survey was conducted in the present study. Full-time registered nurses (n = 150) from Grade A hospitals in Tianjin were surveyed. Pearson correlation, hierarchical regression analyses, and the Sobel test were used in the study.

Results

The results illustrated that positive emotion mediated the relationship between burnout and nurses’ turnover intention.

Conclusions

Nursing administrators should pay more attention to the benefits of positive emotions on working motivation. It is helpful to relieve burnout in the working process so that nurses are willing to remain in their current employment.

Abstract

Background: MiRNA-30c was a tumor suppressor in several human cancers, however, its association with clinicopathological features and prognosis in colorectal cancer (CRC) is unclear.

Materials and Methods: The expression level of miRNA-30c in 192 pairs of colorectal cancer and adjacent normal tissues was detected by Quantitative RT-PCR, the association between miRNA-30c expression and clinical characteristics and prognosis were statistically analyzed.

Results: miRNA-30c was significantly lower in CRC tissues specimens compared with matched normal adjacent tissue (P<0.001). MiRNA-30c was positively correlated with tumor size (P=0.012), TMN stage (P=0.002) and lymph node metastasis (P=0.004). The univariate analysis showed CRC patients with low miRNA-30c had distinctly shorter overall survival (P<0.001) than patients with high miRNA-30c expression level. The multivariate analysis was performed and informed that low miRNA-30c expression (P<0.001) might be an independent prognostic predictor for poor prognosis.

Conclusion: miRNA-30c could predict the prognosis of colorectal cancer which is helpful to choose reasonable treatment measures.

Abstract

The ship’s pilot can obtain the ship auxiliary information through the navigation system, when berthing system can display the parameters such as traverse speed and distance of the ship. But most of the system data show that there are insufficient precision. Taking the CORS system to obtain the location information, data Calculation of Berthing System based on Polar Coordinate Algorithm, this paper puts forward a solution to the “dead point” of the berthing and aiding system, which has a certain reference value for the design of the ship berthing assistance system.

Abstract

The current study is a simplification of related components of large floating roof tank and modeling for three dimensional temperature field of large floating roof tank. The heat transfer involves its transfer between the hot fluid in the oil tank, between the hot fluid and the tank wall and between the tank wall and the external environment. The mathematical model of heat transfer and flow of oil in the tank simulates the temperature field of oil in tank. Oil temperature field of large floating roof tank is obtained by numerical simulation, map the curve of central temperature dynamics with time and analyze axial and radial temperature of storage tank. It determines the distribution of low temperature storage tank location based on the thickness of the reservoir temperature. Finally, it compared the calculated results and the field test data; eventually validated the calculated results based on the experimental results.

Abstract

The Deep Draft Semi-Submersible (DDS) concepts are known for their favourable vertical motion performance. However, the DDS may experience critical Vortex-Induced Motion (VIM) stemming from the fluctuating forces on the columns. In order to investigate the current-induced excitation forces of VIM, an experimental study of flow characteristics around four square-section cylinders in a square configuration is presented. A number of column spacing ratios and array attack angles were considered to investigate the parametric influences. The results comprise flow patterns, drag and lift forces, as well as Strouhal numbers. It is shown that both the drag and lift forces acting on the cylinders are slightly different between the various L/D values, and the fluctuating forces peak at L/D = 4.14. The lift force of downstream cylinders reaches its maximum at around α = 15°. Furthermore, the flow around circular-section-cylinder arrays is also discussed in comparison with that of square cylinders.

Abstract

This paper deals with the problem of robust fault detection (FD) for an unmanned aerial vehicle (UAV) flight control system (FCS). A nonlinear model to describe the UAV longitudinal motions is introduced, in which multiple sources of disturbances include wind effects, modeling errors and sensor noises are classified into groups. Then the FD problem is formulated as fault detection filter (FDF) design for a kind of nonlinear discrete time varying systems subject to multiple disturbances. In order to achieve robust FD performance against multiple disturbances, simultaneous disturbance compensation and H1/H optimization are carried out in designing the FDF. The optimality of the proposed FDF is shown in detail. Finally, both simulations and real flight data are applied to validate the proposed method. An improvement of FD performance is achieved compared with the conventional H1/H-FDF.

Abstract

Signal denoising can not only enhance the signal to noise ratio (SNR) but also reduce the effect of noise. In order to satisfy the requirements of real-time signal denoising, an improved semisoft shrinkage real-time denoising method based on lifting wavelet transform was proposed. The moving data window technology realizes the real-time wavelet denoising, which employs wavelet transform based on lifting scheme to reduce computational complexity. Also hyperbolic threshold function and recursive threshold computing can ensure the dynamic characteristics of the system, in addition, it can improve the real-time calculating efficiency as well. The simulation results show that the semisoft shrinkage real-time denoising method has quite a good performance in comparison to the traditional methods, namely soft-thresholding and hard-thresholding. Therefore, this method can solve more practical engineering problems.

Abstract

Objectives To investigate the clinical features of tuberculosis (TB)-associated immune reconstitution inflammatory syndrome (TB-IRIS) in patients co-infected with HIV/TB or latent infection during highly active antiretroviral therapy (HAART).

Methods HIV-infected patients treated in the Third People’s Hospital of Shenzhen, China between March 2012 and March 2013 were recruited, and divided into 3 groups: 1) HIV/TB co-infection group (n = 50), 2) HIV/ MTB latent infection group (n = 50), and 3) HIV infection group (n = 50), with 12-month follow-up. Patients in the HIV/TB co-infection group were treated with HAART 2 weeks after TB therapy. Patients were assessed at different time-points.

Results The incidence and mortality rates of TB-IRIS were 40% and 10% in the HIV/TB co-infected patients, and 2% (and no mortality) in the HIV/MTB group. The HIV infected group did not display TB-IRIS or death. About 95% HIV/TB co-infected patients were 20-39 years old when TB-IRIS occurred, and 65% of the patients developed TB-IRIS 2 weeks after HAART. For the co-infection group, those with TB-IRIS (20/20, 100%) had fever, with a significantly higher incidence than those who did not develop TB-IRIS (6.7%, 2/30, P < 0.05). The patients with TB-IRIS in co-infection group displayed markedly higher clinical biochemical markers, acute phase reactants, increased CD4+ cell counts, and 2 log10-decreases of HIV RNA loads, compared with the patients not presenting with TB-IRIS (P < 0.05).

Conclusion HIV/TB co-infected patients presented with a high-risk of developing TB-IRIS during HAART treatment. Early diagnosis and treatment could decrease mortality rates in TB-IRIS.

Abstract

TiO2-SiO2 (TiO2 supported on SiO2) photocatalysts were prepared using an ultrasonic-assisted sol-gel method. These photocatalysts were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR) and photoluminescence spectra (PL). Their photocatalytic activities were investigated by the method of methyl orange oxidation. It was found that the photocatalytic activity of TiO2-SiO2 was optimal when the molar ratio of hexadecyl trimethyl ammonium bromide to titanium butoxide was 1:10. The average crystallite size of TiO2-SiO2 was smaller than that prepared by the stirring method. Furthermore, for pure anatase phase samples, it was shown that the lower the photoluminescence intensity, the higher the photocatalytic activity.