Association between Body Mass Index and Early Renal Function after Kidney Transplantation: Observational and Mendelian Randomization Study.

INTRODUCTION: The relationship between BMI and early renal function recovery after kidney transplantation is important due to the rising global obesity rates. METHODS: A retrospective study on 320 patients who received allograft kidney transplantation at Guangxi Medical University Hospital explored the BMI-kidney function relationship using various statistical methods. Mendelian randomization (MR) was also employed to investigate causality. RESULTS: Based on the univariate analysis, multivariate linear regression models, and trend analysis, it was found that there were significant positive correlations between BMI and creatinine, urea, and cystatin C on the 7th day after kidney transplantation (p < 0.05). The sensitivity analysis further confirmed these correlations in different gender stratification, adolescents, and adults. However, the positive correlation with cystatin C was only significant in males. Additionally, after conducting smooth curve fitting analysis and threshold saturation analysis, it was revealed that the negative correlation between early renal function recovery was most significant when BMI was between 22.0 and 25.5 kg/m2, and early postoperative renal function may be optimal when BMI was at 22.2 kg/m2. Finally, the MR analysis confirmed a causal relationship between BMI and renal failure, as indicated by the IVW method (p = 0.003), as well as the weighted median estimator (p = 0.004). CONCLUSION: This study on kidney transplant patients found that maintaining a BMI within the range of 22.0-25.5 kg/m2, with an optimal BMI of 22.2 kg/m2, improves early renal function recovery. This correlation holds true for different age-groups and genders. Monitoring and controlling BMI in high-risk patients can enhance post-transplantation renal function.

A high-entropy alloy with hierarchical nanoprecipitates and ultrahigh strength.

High-entropy alloys (HEAs) are a class of metallic materials that have revolutionized alloy design. They are known for their high compressive strengths, often greater than 1 GPa; however, the tensile strengths of most reported HEAs are limited. Here, we report a strategy for the design and fabrication of HEAs that can achieve ultrahigh tensile strengths. The proposed strategy involves the introduction of a high density of hierarchical intragranular nanoprecipitates. To establish the validity of this strategy, we designed and fabricated a bulk Fe25Co25Ni25Al10Ti15 HEA to consist of a principal face-centered cubic (fcc) phase containing hierarchical intragranular nanoprecipitates. Our results show that precipitation strengthening, as one of the main strengthening mechanisms, contributes to a tensile yield strength (σ0.2) of ~1.86 GPa and an ultimate tensile strength of ~2.52 GPa at room temperature, which heretofore represents the highest strength reported for an HEA with an appreciable failure strain of ~5.2%.

Deformation Mechanisms in a Rolled Magnesium Alloy Under Tension Along the Rolling Direction.

The twinning and slip modes of a rolled magnesium alloy sheet were investigated through quasi-in-situ tensile tests that were carried out along the rolling direction at room temperature with a constant strain rate. Scanning electron microscopy and electron backscattered diffraction observations were used to identify activated twinning and slip systems. Schmid factors were calculated to analyze different deformation modes. The analyses show that a small number of {10-12} tensile twins were present during deformation, and these twins resulted from the accommodation of compression along the tensile direction. Post-deformation examination revealed the dominance of prismatic slip.

Effects of the Tempering and High-Pressure Torsion Temperatures on Microstructure of Ferritic/Martensitic Steel Grade 91.

Grade 91 (9Cr-1Mo) steel was subjected to various heat treatments and then to high-pressure torsion (HPT) at different temperatures. Its microstructure was studied using transmission electron microscopy (TEM) and X-ray diffraction (XRD). Effects of the tempering temperature and the HPT temperature on the microstructural features and microhardness in the ultrafine-grained (UFG) Grade 91 steel were researched. The study of the UFG structure formation takes into account two different microstructures observed: before HPT in both samples containing martensite and in fully ferritic samples.

An Efficient and Cost-Effective Method for Preparing Transmission Electron Microscopy Samples from Powders.

The preparation of transmission electron microcopy (TEM) samples from powders with particle sizes larger than ~100 nm poses a challenge. The existing methods are complicated and expensive, or have a low probability of success. Herein, we report a modified methodology for preparation of TEM samples from powders, which is efficient, cost-effective, and easy to perform. This method involves mixing powders with an epoxy on a piece of weighing paper, curing the powder-epoxy mixture to form a bulk material, grinding the bulk to obtain a thin foil, punching TEM discs from the foil, dimpling the discs, and ion milling the dimpled discs to electron transparency. Compared with the well established and robust grinding-dimpling-ion-milling method for TEM sample preparation for bulk materials, our modified approach for preparing TEM samples from powders only requires two additional simple steps. In this article, step-by-step procedures for our methodology are described in detail, and important strategies to ensure success are elucidated. Our methodology has been applied successfully for preparing TEM samples with large thin areas and high quality for many different mechanically milled metallic powders.

Synthesis and characteristics of monticellite bioactive ceramic.

Mono-phase ceramics of monticellite (CaMgSiO4) were successfully synthesized by sintering sol-gel-derived monticellite powder compacts at 1,480 degrees C for 6 h. The mechanical properties and the coefficient of thermal expansion (CTE) of the monticellite ceramics were tested. In addition, the bioactivity in vitro of the monticellite ceramics was evaluated by investigating their bone-like apatite-formation ability in simulated body fluid (SBF), and the biocompatibility in vitro was detected by osteoblast adhesion and proliferation assay. The results showed that the bending strength, fracture toughness and Young's modulus of the monticellite ceramics were about 159.7 MPa, 1.63 MPa m1/2 and 51 GPa, respectively. The CTE was 10.76x10(-6) degrees C(-1) and close to that of Ti-6Al-4V alloy (10.03x10(-6) degrees C(-1)). Furthermore, the monticellite ceramics possessed bone-like apatite-formation ability in SBF and could release soluble ionic products to significantly stimulate cell growth and proliferation. In addition, osteoblasts adhered and spread well on the monticellite ceramics, which indicated good bioactivity and biocompatibility.