FS-LASIK矫正不同程度近视术后角膜高阶像差的早期变化

目的:探究轻中度和高度近视患者飞秒激光制瓣准分子激光原位角膜磨镶术(FS-LASIK)术后角膜前后表面和整体角膜高阶像差的变化。方法:对2018-12/2019-12在我院行FS-LASIK手术的近视患者129例129眼进行回顾性病例研究,按术前等效球镜度(SE)分为轻中度近视组(SE<-6.00D,76眼)和高度近视组(SE≥-6.00D,53眼)。分别于术前和术后6mo用Pentacam眼前节分析系统测量角膜前后表面和整体角膜的高阶像差。结果:术后6mo,两组角膜前表面和整体角膜的总高阶像差、球差和水平彗差较术前增加,且高度近视组高于轻中度近视组(均P<0.01);两组角膜后表面的水平彗差较术前有差异(均P<0.01),且高度近视组高于轻中度近视组(P<0.01)。两组患者角膜前表面和整体角膜的术源性总高阶像差、球差和水平彗差与术前SE有明显相关性(均P<0.01)。结论:FS-LASIK术后6mo角膜前表面及整体角膜的总高阶像差、球差和水平彗差均较术前增加,且与术前SE明显相关;角膜后表面高阶像差除水平彗差外无明显变化,其远期变化有待进一步研究。

Microstructural evolution in Al–Zn–Mg–Cu–Sc–Zr alloys during short-time homogenization

Abstract： Microstructural evolution in a new kind of aluminum （A1） alloy with the chemical composition of AI-8.82Zn-2.08Mg- 0.80Cu-3.31Sc-0.3Zr was investigated. It is found that the secondary phase MgZn2 is completely dissolved into the matrix during a short homogenization treatment （470℃, 1 h）, while the primary phase A13（Sc,Zr） remains stable. This is due to Sc and Zr additions into the A1 al- loy, high Zn/Mg mass ratio, and low Cu content. The experimental findings fit well with the results calculated by the homogenization diffusion kinetics equation. The alloy shows an excellent mechanical performance after the short homogenization process followed by hot-extrusion and T6 treatment. Consequently, a good combination of low energy consumotion and favorable mechanical properties is obtained.

康柏西普玻璃体腔注射后患眼短期眼压升高的影响因素分析

目的:探讨分析玻璃体腔注射康柏西普后短期眼压(IOP)升高的影响因素。方法:临床前瞻性观察研究。共纳入玻璃体腔注射康柏西普的视网膜病变患者269例269眼,所有患眼均行康柏西普玻璃体腔注射治疗。其中,男143例,女126例;年龄相关性黄斑变性(ARMD)患者201例,其他类型视网膜变性患者68例。平均年龄62.86±11.74岁,采用非接触气动式眼压计,分别在注射前,注射后10、30min,2和4h对患者进行IOP测量。根据注射后10min IOP升高情况来进行分组,IOP升高10 mmHg及以上定义为IOP升高组,IOP升高小于10 mmHg定义为IOP稳定组。采用多因素Logistic回归分析分析两组之间的差异。结果:患者在注射后10、30min,2和4h的平均IOP分别为24.1、20.2、19.5、16.9 mmHg,注射后各个时间点的IOP较注射前平均升高6.7、3.1、1.7、0.5 mmHg。其中,IOP高组56例,IOP稳定组213例。两组患者年龄、最佳矫正视力(BCVA)、性别、眼别、疾病类型比较均无统计学差异(均P>0.05);注药次数(Z=-4.389,P=0.012)、注射前IOP及注射后各时间点的IOP(t=-5.343,-10.467,-8.933,-6.124,-4.635,均P<0.01)比较差异均有统计学差异。多变量Logistic回归分析显示,基础IOP与注射后10min IOP升高呈正相关(B=-0.913,OR=0.521,95%CI:0.211~0.694,P=0.011)。结论:基线IOP水平越高,注射后IOP升高的风险越高。基线IOP是影响玻璃体腔注射康柏西普后患眼短期IOP升高的主要相关因素,而注射次数可能是另一个风险因素。

Expression and role of specificity protein 1 and collagenⅠin recurrent pterygial tissues

AIM:To investigate the expression profiles of the transcription factor specificity protein 1(Sp1)and collagenⅠin recurrent pterygial tissues.What is more,to compare the changes of Sp1 and collagen I among primary pterygial tissue,recurrent pterygial tissue and conjunctival tissue.METHODS:In the prospective study,we collected the pterygial tissues of 40 patients who underwent resection of primary pterygial tissue and recurrent pterygial tissue,and the conjunctival tissues of 10 patients with enucleation due to trauma.The relative expression levels of Sp1 and collagen I were analyzed by reverse transcription quantitative-polymerase chain reaction and Western blot.Paired t-test was performed to compare the Sp1 and collagen I of recurrent pterygial tissues,as well as the primary pterygial tissues and conjunctival tissues.In further,Pearson’s hypothesis testing of correlation coefficients was used to compare the correlations of Sp1 and Collagen I.RESULTS:The content of Sp1 and collagen I m RNA and protein was significantly greater in recurrent pterygial tissue than that was in primary and conjunctival tissue(P<0.05).There was a positive correlation between the m RNA and protein levels of Sp1 and collagen I in recurrent pterygial tissues(protein:r=0.913,P<0.05;m RNA:r=0.945,P<0.05).CONCLUSION:Sp1 and collagen I are expressed in normal conjunctival,primary,and recurrent pterygial tissues,but expression is significantly greater in the latter.Sp1 and collagen I may be involved in the regulation of the development of recurrent pterygium.

Microstructural evolution and mechanical behavior of in situ synthesized MgAl_(2)O_(4)whiskers reinforced 6061 Al alloy composite after hot extrusion and annealing

In situ synthesized MgAl2O4whiskers reinforced 6061 Al alloy composites were fabricated by a powder metallurgy method.Nano-sized MgAl2O4spinel whiskers distributed uniformly in 6061 Al alloy matrix without any interfacial product and laid along the extrusion direction after hot extrusion.As-extruded composite samples were annealed at 530,580,600 and 630℃for 1 h and examined by electron backscattered diffraction to investigate the recrystallization behavior of obtained composites.Microstructure and texture evolution was investigated,and it is found that the recrystallization process is inhibited by whiskers because of Zener pinning.Slender fibrous grains remain until 630℃,and deformation textures still exist even in specimen annealed at 630℃.Hardness and tensile tests show that the completely recrystallized sample has an ultimate tensile strength of 218 MPa and a hardness of HV52 compared with 283 MPa and HV 69 of the unannealed sample.Mechanical properties of the annealed samples decline slightly with annealing temperature increasing up to 600℃.

Carbon and few-layer MoS2 nanosheets co-modified TiO2 nanosheets with enhanced electrochemical properties for lithium storage

Carbon and few-layer MoS2 nanosheets co- modified TiO2 nanocomposites （defined as MoS2-C@TiO2） were prepared through a facile one-step pyrolysis reaction technique. In this unique nanostructure, the TiO2 nanosh- eets with stable structure serve as the backbones, and carbon coating and few-layer MoS2 tightly adhere onto the surface of the TiO2. It needs to be pointed out that the carbon coating improves the overall electronic conductivity and the few-layer MoS2 facilitates the diffusion of lithium ions and offers more active sites for lithium-ion storage. As a result, when evaluated as lithium-ion battery anodes, the MoS2-C@TiO2 nanocomposites exhibit markedly enhanced lithium storage capability compared with pure TiO2. A high specific capacity of 180 mA.h.g-1 has been achieved during the preliminary cycles, and the specific capacity can maintain 160 mA.h.g-1 at a high current density of 1C （1C=167 mA.g-1） even after 300 discharge/ charge cycles, indicating the great potential of the MoS2- C@TiO2 on energy storage.

Microstructure and tensile properties of A356 alloy with different Sc/Zr additions

Addition of rare earth elements for improving the tensile properties of aluminum alloys has attracted great attention. In this study, a systematic analysis on the microstructure and tensile properties of A356–0.13 Ti alloys with different contents of scandium(Sc) and scandium/zirconium(Sc/Zr) after solution and aging treatment process was carried out. The addition of Sc/Zr into A356–0.13 Ti alloys can greatly refine the grain size and modify the deleterious coarse eutectic Si structure and harmful acicular iron-containing phase morphology. As a result, the maximum value of strength(298 MPa) and ductility(elongation of 8.4%) are acquired by co-addition of Sc/Zr after solution and aging treatment process, which indicates that the tensile properties of A356 alloy are greatly enhanced by the synergistic effect of co-addition of Sc/Zr.

Fabrication of Carbon Nanotube-Reinforced 6061Al Alloy Matrix Composites by an In Situ Synthesis Method Combined with Hot Extrusion Technique

Carbon nanotube （CNT）-reinforced 6061Al alloy matrix composites were prepared by chemical vapor depo- sition （CVD） combined with hot extrusion technique. During the preparation process, the 6061Al flakes obtained by ball milling of the 6061Al spherical powders were subjected to surface modification to introduce a hydrophilic polyvinyl alcohol （PVA） membrane on their surface （6061Al@PVA） to bond strongly with nickel acetate [Ni（II）]. Then the 6061Al@PVA flakes bonded with Ni（II） were calcined and reduced to Ni nanoparticles, which were then heat-treated at 580 ℃ to remove PVA for obtaining even Ni/6061Al catalyst. After that, the as-obtained Ni/6061Al catalyst was employed to synthesize CNTs on the surface of the 6061Al flakes by CVD. After hot extrusion of the CNT/6061Al composite powders, the as-obtained CNT/6061Al bulk composites with 2.26 wt% CNTs exhibited 135% increase in yield strength and 84.5% increase in tensile strength compared to pristine 6061Al matrix.