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Purpose The purpose of the study is to observe the effects of active vitamin D supplementation on insulin resistance and islet β-cell function (HOMA-β) in patients with non-diabetic chronic kidney disease (NDCKD). Methods A total of 134 patients with NDCKD who met the inclusion criteria were enrolled in the prospective controlled study and categorized as such: 60 patients in the non-dialysis (ND) group; 36, hemodialysis (HD) group; and 38, peritoneal dialysis (PD) group. Each group was divided into two equal-numbered subgroups for vitamin D supplementation. Those in the experimental subgroups received calcitriol 0.5 ug/day orally, and were followed-up for 6 months. A total of 117 patients were followed-up, including 57 patients in the ND group; 29, HD group; and 31, PD group. Changes in the insulin resistance index (HOMA-IR) and HOMA-β index were calculated and compared at the time of enrollment and after 1, 3, and 6 months of intervention. Results (1) Mean HOMA-IR value: In the ND group, mean HOMA-IR value of the experimental group significantly decreased compared with that of the control group after 3 months of intervention (P = 0.02). In the HD and PD groups, there was no statistical difference between the experimental and control groups (P > 0.05). (2) Mean HOMA-β index: In the ND group, mean HOMA-β index of the experimental group was higher than that of the control group after 1 month of active vitamin D treatment (P = 0.03), and, with an extended intervention time, the index gradually increased (P P = 0.01). Among PD patients, mean HOMA-β index of the patients in the experimental group was higher than that of the control group after 6 months of active vitamin D treatment (P = 0.02). Conclusions Active vitamin D supplementation improved insulin resistance and HOMA-β after 6 months in ND patients, but only improved HOMA-β in the dialysis patients, with no significant effect on insulin resistance.

As a high-efficiency and high-quality welding process, hybrid laser-MAG welding (HLMW) has significant potential of application in welding thick plates. In the present study, based on thermal elastic–plastic theory, a three-dimensional finite element model is developed to predict the weld shape characteristics, residual stress and distortion in HLMW for a butt joint of 12-mm-thick high strength steel plate. Metal active gas arc welding (MAG) heat input and laser energy are modeled as one double-ellipsoid body heat source and one cone body heat source with enhanced peak density along the central axis, respectively. The comparison between calculated molten pool shapes and those obtained by the experiment shows a good agreement. Then weld shape characteristic, residual stresses and distortions are calculated in four different welding process parameters. The results show that the increase of laser power and current can effectively increase the weld penetration width when the welding speed is fixed. At the top surfaces of weldment, the peak stress of high laser beam power is more significant than that of low laser beam power. A high compressive transverse stress of low laser beam power can be found at the welding zone and the surrounding heat affected zone. However, at the bottom surfaces of weldment, the peak stress of low laser beam power is larger than that of high laser beam power. The peak stress of low laser beam power is much larger than that of high laser beam power. A high compressive transverse stress of low laser beam power can be found at the welding zone. The vertical deformation in low laser beam power and low arc current welding has the lowest value.

The optimization of welding parameters of the welded joints of TC4 titanium alloys/304 stainless steel (TC4/304 SS) by friction stir lap welding (FSLW) based on orthogonal test was researched. The results show that under low heat input (low rotating speed and high traversing speed), there was a damaging defect in stir zone (SZ) and cracks started from the defect under the tension. Under high heat input (high rotating speed and low traversing speed), the intermetallic compounds were barely formed, and the cracks formed from 304 SS blocks existed in thermal mechanically affected zone of TC4 titanium alloys (TMAZTC4), eventually obtaining the highest fracturing load. However, under middle heat input (middle rotating speed and low traversing speed), the intermetallic compounds and the maximum hardness were found at the interface, and cracks started from these compounds under the tension, getting a middle fracture load. In conclusion, the joints with good properties can be obtained with high rotating speed and low traversing speed.

Top-quality aluminum alloy weld beads, exploiting the double-sided heat source synergic welding (DSHSSW) process, were obtained with medium heat input, no arc spacing, no root gap, and upward vertical direction. The energy utilization was reduced with the augmented arc spacing because of the attendant increased heat dissipation. Compared with one-side welding (OSW), the fusion area and melting efficiency of DSHSSW were enormously raised, indicating the enhancement of melting performance and energy utilization, and superior joints could be fabricated using DSHSSW under the identical heat input. Additionally, the DSHSSW arc was constricted and thus improved the energy density in contrast to OSW. As the weld penetration deepened during DSHSSW, the heat conduction space was diminished, and the heat accumulation effect was generated. The arc contraction and heat accumulation effect mutually lead to the increased penetrating ability during DSHSSW.

The early corrosion stage of carbon steel welded joints in water occurring in a CO2-saturated oilfield was investigated. Electron backscatter diffraction (EBSD) and energy dispersive X-ray spectrometry (EDS) were used to characterize the microstructure and chemical composition distribution of the different zones in the welded joint. Atomic force microscopy (AFM) and a VEECO optical profiler were used to observe the sample surface corrosion morphology at different immersion times. The results show that the early stage corrosion characteristics of each zone in the welded joint are related to grain orientation and not related to grain size, grain boundary type, or to the second phase. Additionally, it was found that chemical composition distribution is the primary reason for the differences in the early stage corrosion characteristics observed for each zone in the welded joints.

Safety evaluation of resistance spot welds necessitates the accurate measurement of local constitutive properties. This study employed miniature mechanical tests to investigate the deformation and failure behaviors of nugget, heat affected zone (HAZ), and corona bond of resistance spot welded JSC980YL steel. A novel mini-peel test was developed to enable local fracture in HAZ for numerical inverse calibration of constitutive parameters. The fracture constants of weld zones calibrated using Cockcroft-Latham ductile failure criterion were incorporated in finite element models to predict the failure modes of spot welds in tensile-shear and cross-tension coupon tests. The result indicates that the ultimate tensile strengths of the nugget and the corona bond were 37.6% higher and 5.8% lower, respectively, than that of the base material. The nugget and HAZ exhibited ductile fracture, whereas the corona bond was brittle fracture with only 1.2% elongation. In the coupon tests, the increase of nugget diameter slowed down the damage accumulation rate in the nugget and accelerated that in the HAZ, resulting in the transition of failure mode from interfacial to pullout. The failure load of corona bond in coupon tests increased with the increase of nugget diameter while its contribution to the peak load decreased.

Although TiO2 with outstanding photocatalytic activity has wide applications as a photo-to-electricity conversion material, the electrochemical energy storage of TiO2-based electrodes is commonly restricted by inherent limitations such as intrinsic low theoretical specific capacitance and poor electroconductivity. In this study, we introduce highly uniformed spaced TiO2 nanotube arrays (NTA) as a robust ultrathin scaffold and current collector in a potassium ion electrochemical storage capacitor. By integrating a simple surface-charge regulation with successive ionic adsorption technique, we construct both the cathodic and anodic electroactive materials on a TiO2 NTA based ~5 μm film. Hierarchical MnO2 nanosheets modified TiO2 NTA cathode exhibited a high volumetric capacitance of 1051 F cm−3, and the Fe2O3 nanospindles anchored TiO2 NTA anode exhibited a volumetric capacitance of 608.2 F cm−3. Based on the as-prepared cathode and anode, the assembled asymmetric supercapacitor with a thickness of only 0.4 mm exhibits a high energy density of 2.67 mWh cm−3 in K2SO4 electrolyte with 91.7% capacitance retention after 5000 cycles. The deformable Ti-substrate, excellent stability, good biocompatibility, and satisfactory capacitance in a neutral aqueous system enable the as-proposed supercapacitor a promising energy-storage system, thus expanding the application potentials of TiO2 photocatalysis based energy conversion devices.

A multilayered carbon nanosphere (CNS)/manganese oxide (MnO2) nanofilm is fabricated by a newly developed layer-by-layer (LBL)–post-infiltration approach. The multilayered architecture effectively shortens the length over which ions diffuse, and the nanoscaled carbon/MnO2 interface provides an interconnected pathway for electron conduction. MnO2 acts not only as the redox center for charge storage, but also as the spacer between the LBL-assembled multilayers for more rapid electrolyte transport. A specific capacitance (based on MnO2) of 1134.0 F g−1 is achieved at a loading of 5.22 μg cm−2 in a neutral electrolyte. This strategy provides a promising approach for fabricating high-power and high-energy electrochemical capacitors with precise control of electrode thickness on geometric device surfaces.

Chronic heart failure with normal left ventricular ejection fraction (HFNEF) is not only common, but also carries a high risk of substantial morbidity and mortality. However, few studies have been conducted in this population and no proven treatment is available. Although beta-blockers are evidence-based first-line therapy in systolic heart failure, they have not been well studied in HFNEF.This study is a multicentre, prospective, randomized, open-label, blinded endpoint (PROBE) trial. A total of 1200 patients will be randomized to either beta-blocker (metoprolol succinate) or control (n = 600 per group). The primary endpoint is a composite of hospitalization for heart failure and cardiovascular death. The secondary endpoints include cardiovascular death, heart failure mortality or hospitalization, all-cause mortality, change in New York Heart Association class, change in left ventricular ejection fraction, increase in NT-proBNP (byor = 50% of the value at randomization), beta-blocker tolerance, and premature termination of beta-blocker therapy due to adverse events. The follow-up period is a minimum of 2 years.This study will provide important evidence, for the first time to our knowledge, of the long-term efficacy of beta-blocker therapy in the management of HFNEF.