阿托伐他汀钙片治疗老年白内障术后患者的效果

目的:研究阿托伐他汀钙片治疗老年白内障术后患者的效果。方法:选择2020年1月—2022年1月南漳县中医医院眼科收治的88例拟行手术治疗的老年白内障患者作为研究对象,按照随机数表法分为两组,各44例。所有患者均行超声乳化手术,观察组在术后给予阿托伐他汀钙片口服,对照组不另外服药。比较两组治疗效果、术后不同时段黄斑中心凹视网膜厚度(CRT)、最佳矫正视力(BCVA)、血脂水平[总胆固醇(TC)、低密度脂蛋白胆固醇(LDL-C)、高密度脂蛋白胆固醇(HDL-C)]。结果:观察组治疗总有效率为95.45%,显著高于对照组的81.82%,差异有统计学意义(P<0.05)。术后3周、12周、24周,两组CRT均高于术后1 d,但观察组低于对照组;术后12周、24周,两组CRT低于术后3周;术后24周,两组CRT均低于术后12周,差异有统计学意义(P<0.05)。术后1周、3周、6周,两组BCVA均高于术前;术后3周、6周,两组BCVA均高于术后1周;术后6周,两组BCVA均高于术后3周;术后3周、6周,观察组BCVA均高于对照组,差异有统计学意义(P<0.05)。术后12周,两组TC、LDL-C水平均低于术前,HDL-C水平高于术前,且观察组TC、LDL-C水平均低于对照组,HDL-C水平高于对照组,差异有统计学意义(P<0.05)。结论:老年白内障患者术后应用阿托伐他汀钙片可有效控制患者血脂水平,从而改善视力,降低黄斑水肿发生风险,提升治疗效果。

Determination of stacking fault energies in a high-Nb TiAl alloy at 298 K and 1273 K

The stacking fault energies of Ti-46Al-8.5Nb-0.2W alloy at 298 K and 1273 Kwere determined. The principle for the determination of the stacking fault energies is based on thefact that the stacking fault energy and the elastic interaction energy acting on the dissociatedpartial dislocations are equal. After the compress deformations with the strain of 0.2% at 298 K and1273 K, and water quench to maintain the dislocation structures deformed at 1273 K, thedissociation distances between two partial dislocations were determined by weak beam transmissionelectron microscopy (WBTEM) technique. Based on these dissociation distances and the correspondingcalculation method, the stacking fault energies were determined to be 77-81 mJ/m^2 at 298 K and tobe 57-60mJ/m^2 at 1273 K respectively.

Effects of small amount Ta on the characteristics of the Zr-Al-Ni-Cu-Ta bulk metallic glass

The effects of Ta on the characteristics of the Zr-base BMG (bulk metallic glass) were investigated. Zr55Al10Ni5Cu30-xTax (x=1, 2,4) bulk metallic glasses (BMGs) with 3.5 mm diameter and 70 mm length were successfully prepared by using combined jet and copper mold casting. A small amount of Ta addition does not change the glass transition temperature, crystallization temperature, and supercooled liquid region obviously, but Ta promotes composition separation and two-stage crystallization. The stable crystalline phases include Zr2Ni, CuZr2, Al2Zr3 intermetallic compounds and Ta-rich solid solution after annealing the Zr-Al-Ni-Cu-Ta alloys at 753 K. Zr55Al10Ni5Cu30-xTax (x=1,2,4) bulk glassy alloys exhibit a better compressive strength. The stress-strain curve shows a zigzag feature, and the fracture surface shows intersecting of shear bands. It may correlate with the inhomogeneous feature of amorphous structure.

Observation and computer simulation of multicomponent chemical short-range order (MCSRO) for the bulk metallic glasses

The atomic configuration of chemical short-range order (CSRO) for the Zr-base metallic glasses was investigated by using nano-diffraction and high resolution transmission electronic microscopy (HRTEM) technology with a beam size of 0.5 nm. It is il- lustrated that the pattern of atomic configuration of CSRO might have various compound counterparts because of the chemical inter- action of bonding atoms. Some atomic configuration of MCSRO is similar to the icosahedral structure with 10-fold symmetry of very weak spots. In deed, the nano-beam technology could clearly detect the evolution of atomic configuration in nanometer scale during the transformation from the metallic melt to the primary crystallization. The local atomic configuration of CSRO is also investigated by molecular dynamics simulation (MD) for the Zr2Ni compound in a wider temperature range. The CSRO in the melt could be pic- torially demonstrated as distorted coordination polyhedron of the compound structure and/or the structure similar to cubo-octahedron analogs. The MD simulation illustrates that the atomic packing of long-range order disappears just above the melting point, but the chemical interaction of bonding atoms still exists that leads to form the various CSRO with the atomic configuration similar to stable or metastable unit cell of Zr2Ni compound. The icosahedral polyhedron became more abundance as the overheating temperature was raised.

Crystalline Precipitate in a Bulk Glass Forming Zr-Based Alloy and Its Effect on Mechanical Properties

Cylindrical and sheet samples of bulk metallic glass with a nominal composition of Zr52.5Ni14.6-Al10Cu17.9Ti5 (at. pct) were prepared by melt injection casting. The crystalline precipitates formed during the casting were studied by metallographic observations and selected-area electron diffractions. The effect of crystalline precipitates on the mechanical properties were investigated by tensile and compressive tests at room temperature. Oxygen contents and the sample sizes (or cooling rates) strongly affect the formation of the crystalline precipitates. Overheating the alloy melt up to 200 K above its melting temperature can effectively prevent the formation of the crystalline precipitates to get fully glass samples with diameters up to 2 mm for cylinders and thickness up to 1 mm for sheets even the oxygen content is as higher as 0.08 wt pct. With increasing the sample sizes, the crystalline precipitates increase in volume fraction and size. The formation of the precipitates experienced two stages, i.e., initially nucleation and isotropic growth, and then anisotropic growth, finally forming faceted morphologies. Fully glassy Zr52.5Ni14.6Al10Cu17.9Ti5 alloy exhibits excellent tensile and compressive properties at room temperature. The presence of crystalline precipitates significantly decreases the tensile and compressive properties. With increasing the crystalline precipitates, the area of vein patterns on the fracture surface decreases, but the fracture steps increase, and the fracture mode changes from ductile to brittle resulting from the larger stress concentration caused by the larger sizes and faceted shapes of the crystalline precipitates.