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Background: In light of inconsistent evidence from previous observational studies regarding the correlation between serum vitamin D levels and urolithiasis, this study aimed to investigate the genome-wide causal association between genetically predicted serum 25(OH)D levels and urolithiasis using the Mendelian randomization (MR) approach. Methods: In this study, we utilized genome-wide association studies (GWAS) summary statistics from the UK Biobank and SUNLIGHT consortium for serum vitamin D levels, as well as urolithiasis data from FinnGen. We employed bidirectional two-sample MR analysis to evaluate potential causal relationships. The primary MR analysis relied on the inverse variance weighted (IVW) method, supplemented by MR-Egger, weighted median, and weighted mode approaches. Sensitivity analyses were conducted to ensure result robustness, including Cochran’s Q test, MR-Egger intercept test, leave-one-out tests, and MR pleiotropy residual sum and outlier (MR-PRESSO) test. Results: The MR analysis indicated no significant causal effects of serum 25(OH)D levels on urolithiasis [IVW method: (kidney and ureteral stones: OR = 1.134;95% CI, 0.953 to 1.350, p = 0.155; lower urinary tract stones: OR = 1.158; 95% CI, 0.806 to 1.666, p = 0.428)]. However, according to the IVW results, genetically predicted kidney and ureteral stones were associated with decreased serum 25(OH)D levels (beta = -0.025; 95% CI, -0.048 to -0.003; p = 0.028), while they did not indicate a causal effect of lower urinary tract stones on serum 25(OH)D levels (beta = -0.002; 95% CI, -0.013 to -0.008; p = 0.662). A sensitivity analysis suggested the robustness of these causal associations. Conclusions: Our MR study did not provide evidence supporting a causal association between serum 25(OH)D levels and urolithiasis among individuals of European descent. However, there might exist a negative causal association between kidney and ureteral stones and serum 25(OH)D levels. [ABSTRACT FROM AUTHOR]

This paper presents autonomous docking of an inhouse built resident Remotely Operated Vehicle (ROV), called Rover ROV, through acoustic guided techniques. A novel cage-type docking station has been developed. The docking station can be placed on a deep-sea lander, taking the Rover ROV to the seafloor. Instead of using vision-based pose estimation techniques and expensive navigation sensors, the Rover ROV docking adopts an ultra-short baseline (USBL) and low-cost inertial sensors to build an adaptive fault-tolerant integrated navigation system. To solve the problem of sonar-based failure positioning, the measurement residuals are exploited to detect measurement faults. Then, an adaptation scheme for estimating the statistical characteristics of noise in real-time is proposed, which can provide robust and smooth positioning results. It is more suitable for a compact and low-cost deep-sea resident ROV. Field experiments have been conducted successfully in the Qiandao Lake and the South China Sea area with a depth of 3000 m, respectively. The experimental results show that the functionality of autonomous docking has been achieved. Under the guidance of the navigation system, the Rover ROV can autonomously and efficiently return to the docking station within a range of 100 m even when the amounts of outliers exist in the acoustic positioning data. These achievements can be applied to current ROVs by an easy retrofit. [ABSTRACT FROM AUTHOR]

A series of cardo poly(aryl ether sulfone) copolymers bearing pendent sulfonic acid groups (SPES- X) have been prepared by a facile chemical graft method. The structure was confirmed by H-NMR spectra. The side-chain-type SPES- X membranes show significantly reduced swelling behavior and excellent mechanical properties as well as appropriate proton conductivity compared to the main-chain-type sulfonated polymers with similar ion exchange capacity (IEC) value. Moreover, they show methanol permeability in the range of 0.6 × 10−5.7 × 10 cm/s which is lower than that of Nafion 117. All the results indicate that the SPES- X membranes are promising candidates for the direct methanol fuel cells. [ABSTRACT FROM AUTHOR]

This paper proposes a geometrically exact formulation for three-dimensional static and dynamic analyses of the umbilical cable in a deep-sea remotely operated vehicle (ROV) system. The presented formulation takes account of the geometric nonlinearities of large displacement, effects of axial load and bending stiffness for modeling of slack cables. The resulting nonlinear second-order governing equations are discretized spatially by the finite element method and solved temporally by the generalized- α implicit time integration algorithm, which is adapted to the case of varying coefficient matrices. The ability to consider three-dimensional union action of ocean current and ship heave motion upon the umbilical cable is the key feature of this analysis. The presented formulation is firstly validated, and then three numerical examples for the umbilical cable in a deep-sea ROV system are demonstrated and discussed, including the steady configurations only under the action of depth-dependent ocean current, the dynamic responses in the case of the only ship heave motion, and in the case of the combined action of the ship heave motion and ocean current. [ABSTRACT FROM AUTHOR]

To enhance cell attachment and promote liver functions of hepatocytes cultured in bioreactors, a chitosan nanofiber scaffold was designed and prepared via electrospinning. Effects of the scaffold on hepatocyte adhesion, viability and function were then investigated. Data showed that hepatocytes on chitosan nanofiber scaffold exhibited better viability and tighter cell-substrate contact than cells on regular chitosan film. In addition, urea synthesis, albumin secretion and cytochrome P450 activity of hepatocytes on chitosan nanofiber scaffold were all 1.5 to 2 folds higher than the controls. Glycogen synthesis was also increased as compared with the controls. These results suggested the potential application of this chitosan nanofiber scaffold as a suitable substratum for hepatocyte culturing in bioreactors. [ABSTRACT FROM AUTHOR]