52 research outputs found

    miR-199a-5p inhibits aortic valve calcification by targeting ATF6 and GRP78 in valve interstitial cells

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    Calcific aortic valve disease (CAVD) is an important cause of disease burden among aging populations. Excessive active endoplasmic reticulum stress (ERS) was demonstrated to promote CAVD. The expression level of miR-199a-5p in patients with CAVD was reported to be downregulated. In this article, we aimed to investigate the function and mechanism of miR-199a-5p in CAVD. The expression level of miR-199a-5p and ERS markers was identified in calcific aortic valve samples and osteogenic induction by real-time quantitative polymerase chain reaction (RT-qPCR), immunohistochemistry, and western blotting (WB). Alizarin red staining, RT-qPCR, and WB were used for the verification of the function of miR-199a-5p. The dual luciferase reporter assay and rescue experiment were conducted to illuminate the mechanism of miR-199a-5p. In our study, the expression level of miR-199a-5p was significantly decreased in calcified aortic valves and valve interstitial cells’ (VICs) osteogenic induction model, accompanying with the upregulation of ERS markers. Overexpression of miR-199a-5p suppressed the osteogenic differentiation of VICs, while downregulation of miR-199a-5p promoted this function. 78 kDa glucose-regulated protein (GRP78) and activating transcription factor 6 (ATF6), both of which were pivotal modulators in ERS, were potential targets of miR-199a-5p. miR-199a-5p directly targeted GRP78 and ATF6 to modulate osteoblastic differentiation of VICs. miR-199a-5p inhibits osteogenic differentiation of VICs by regulating ERS via targeting GRP78 and ATF6

    A New Method for Analysing the Pressure Response Delay in a Pneumatic Brake System Caused by the Influence of Transmission Pipes

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    This study aims to propose an analysis method for resolving the pressure response of a pneumatic brake circuit considering the effect of a transmission pipe. Pneumatic brake systems (PBS) are widely used in commercial vehicles. The pressure response characteristic of the PBS is the key factor affecting braking performance. By using the thermodynamics of a variable-quality system, the pressure response model of the brake chamber is established, which includes the dynamic model of the pipe considering the unsteady friction and heat transfer. The partial-differential control equations of pipe are solved by introducing the constrained interpolation profile (CIP) method, and a virtual chamber model is proposed to set the boundary condition so as to solve the pressure response in the brake chamber simultaneously. Thus, the regularity of the brake pressure response is obtained by considering the influence of the pipe. Lastly, the model is verified experimentally. The present study indicates that the main factors that affect the pressure response delay are the pipe length and the combination forms of the sonic conductances of the orifices inlet and outlet. Furthermore, it helps to verify that the CIP method is an effective way of solving the pressure response of a brake circuit because of its high accuracy. The present study serves as a foundation for the design and analysis of a PBS

    Microneedles-Based Transdermal Drug Delivery Systems: A Review

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    Photoinhibition-like damage to the photosynthetic apparatus in plant leaves induced by submergence treatment in the dark.

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    Submergence is a common type of environmental stress for plants. It hampers survival and decreases crop yield, mainly by inhibiting plant photosynthesis. The inhibition of photosynthesis and photochemical efficiency by submergence is primarily due to leaf senescence and excess excitation energy, caused by signals from hypoxic roots and inhibition of gas exchange, respectively. However, the influence of mere leaf-submergence on the photosynthetic apparatus is currently unknown. Therefore, we studied the photosynthetic apparatus in detached leaves from four plant species under dark-submergence treatment (DST), without influence from roots and light. Results showed that the donor and acceptor sides, the reaction center of photosystem II (PSII) and photosystem I (PSI) in leaves were significantly damaged after 36 h of DST. This is a photoinhibition-like phenomenon similar to the photoinhibition induced by high light, as further indicated by the degradation of PsaA and D1, the core proteins of PSI and PSII. In contrast to previous research, the chlorophyll content remained unchanged and the H2O2 concentration did not increase in the leaves, implying that the damage to the photosynthetic apparatus was not caused by senescence or over-accumulation of reactive oxygen species (ROS). DST-induced damage to the photosynthetic apparatus was aggravated by increasing treatment temperature. This type of damage also occurred in the anaerobic environment (N2) without water, and could be eliminated or restored by supplying air to the water during or after DST. Our results demonstrate that DST-induced damage was caused by the hypoxic environment. The mechanism by which DST induces the photoinhibition-like damage is discussed below

    The urban-rural disparities and factors associated with the utilization of public health services among diabetes patients in China

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    Abstract Background Basic public health services for diabetes play an essential role in controlling glycemia in patients with diabetes. This study was conducted to understand the urban-rural disparities in the utilization of basic public health services for people with diabetes and the factors influencing them. Methods The data were obtained from the 2018 China Health and Retirement Longitudinal Study (CHARLS) with 2976 diabetes patients. Chi-square tests were used to examine the disparities in the utilization of diabetes physical examination and health education between urban and rural areas. Logistic regression was performed to explore the factors associated with the utilization of diabetes public health services. Results Among all participants, 8.4% used diabetes physical examination in the past year, and 28.4% used diabetes health education services. A significant association with age (OR = 0.64, 95% CI:0.49–0.85; P < 0.05) was found between patients’ use of health education services. Compared with diabetes patients living in an urban area, diabetes patients living in a rural area used less diabetes health education. (χ2= 92.39, P < 0.05). Patients’ self-reported health status (OR = 2.04, CI:1.24–3.35; P < 0.05) and the use of glucose control (OR = 9.33, CI:6.61–13.16; P < 0.05) were significantly positively associated with the utilization of diabetes physical examination. Patients with higher education levels were more likely to use various kinds of health education services than their peers with lower education levels (OR = 1.64, CI:1.21–2.22; P < 0.05). Conclusion Overall, urban-rural disparities in the utilization of public health services existed. Vulnerable with diabetes, such as those in rural areas, are less available to use diabetes public health services. Providing convenient health service infrastructure facilitates the utilization of basic public health services for diabetes in older patients with diabetes, especially in rural areas

    Study on Stratified Settlement and Weak Reflectivity Fiber Grating Monitoring of Shield Tunnel Crossing Composite Strata

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    This paper proposes a set of field test technology system for layered settlement of composite strata based on weak reflectivity fiber Bragg grating sensing technology based on the shield project of “Keyuan Station ~ Shenzhen University Station” section of Shenzhen Metro Line 13, and through the comparison and verification of three-dimensional numerical simulation and field monitoring, the law and distribution characteristics of disturbance settlement of ground surface and overlying strata during shield tunneling are systematically analyzed, and the vertical and horizontal zoning (layer) system for the spatial and temporal evolution of layered settlement of composite strata during shield tunneling is constructed. On this basis, the targeted settlement control technical measures and recommendations are proposed. The findings show that the weak reflectivity fiber grating sensing technology can better perceive the evolution law and distribution characteristics of vertical and horizontal settlement of composite strata caused by shield tunneling, which is in good agreement with the numerical simulation results, and has the advantages of automation and high precision, it can be used as a supplement and alternative method for traditional measurement methods. The stratum deformation is small and layered settlement is not obvious in shield approaching stage (−5D~0), after shield crossing and shield tail falling (0~3D), the stratum is the longitudinal main deformation zone of shield tunneling disturbance, and the influence range of the whole tunneling disturbance is about (−1D~3D). Meanwhile, according to the influence degree of shield tunneling disturbance, the overlying strata of the tunnel can be divided into main disturbance layer and secondary disturbance layer, and the main disturbance layer is located in the range of 0.5D above the tunnel. In addition, based on the different stages of shield tunneling and the vertical and horizontal zoning (layers) of existing structures such as buildings (structures), the settlement control measures and suggestions are proposed. The research results demonstrate the feasibility of weak reflectivity fiber grating for distributed and continuous strata monitoring. It has important guiding value for improving the understanding of settlement law produced from shield construction in composite strata and analyzing and predicting potential risks resulting from shield construction. It also provides reference value for future subway design and construction
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