前表面磷脂修饰的硅凝胶人工晶状体表面生物学特性研究

随着超声乳化白内障吸除术的发展，软性的人工晶状体（intraocular lens，IOL）因可折叠、手术切口小、术后效果好，已成为目前IOL的发展趋势。临床常用的软性IOL大体可分为亲水的和疏水的两大类，各有其优缺点。临床观察发现亲水的IOL术后与前表面相关的病理变化较轻，如炎性反应和晶状体前囊膜混浊轻，而与后表面相关的病理变化重，即后囊膜混浊重；疏水的IOL则与亲水的IOL相反。硅凝胶软性IOL是疏水软性IOL的主要材料，有优良的本体性状，临床证明其疏水的后表面和直角边缘能减少晶状体后囊膜混浊的发生。然而，经过数十年的临床应用，发现硅凝胶软性IOL表面易黏附细菌和炎性细胞，引起的前表面相关并发症重，因而需要对其进行前表面改性及处理，研制一种前表面亲水后表面疏水的新型IOL。

长期服用氯丙嗪致角膜和晶状体色素沉着一例

患者女44岁16年前始因精神疾病口服氯丙嗪控制,4年前平均剂量为400mg/d,近4年改为200mg/d。全身其他系统无特殊病史。右眼视力1.0（-2.00D）,左眼视力0.8（-2.00D）。角膜表面及基质清晰,睑裂区角膜内皮细胞面见双眼一致性弥漫性棕黄色色素颗粒沉着,间隙分明（图1）。房角开放。房水闪辉征（-），无浮游颗粒。虹膜色泽无异常。瞳孔对光反应灵敏。瞳孔区晶状体表面亦见棕黄色浓淡不均的色素沉积。散瞳后其他部位未见类似色素（图2）。深皮质及核未见明显混浊。玻璃体及眼底未检及异常。

Nd:YAG Laser Lysis of the Fibrinous Membrane and Remnant Substance on the Anterior Surface of Intraocular Lens

Purpose:To determine the effects of ND:YAGlaser to disrupt the fibrinous membrane and remnant substance on the anterior surface of intraocular lens.Methods:Nd:YAGlaser was applied on 23cases of fibrinous membrane forma-tion and 8cases of remnant substance on the anterior surface of intaocular lenses(IOL)which had not reponded well to steroid therapy,Eighteen cases were male and 13female.The mean age was49.7years(range,5-78years),The in-terval between IOL implantation and laser therapy was 0.5-30months in the fibrinous membrane cases and 3-10days in the remnant substance cases.The energy applied was0.8-3.0mJ/exp.with2-112exposures.mean follow-up period was3.6months.Results:Complications during therapy included only 2cases of slight iris bleed-ing,Visual acuity after therapy was improved 1line in 16cases,2lines in 11cas-es,3lines in 1case,4lines in 1case and 5lines in 2cases,No post-therapy com-plication was found.Conclusions:Nd:YAG laser lysis is an effective alternative to ramove the fibri-nous membrane and remnant substances on the anterior surface of IOL.Eye Sci-ence1995;11:128-130.

光学测厚仪测量前房深度:应用Haag-Streit方法的系统性差别

Background/aim: Haag-Streit recommends that for the most accurate anterior chamber depth (ACD) results, the corneal thickness, as determined with attachment No I, should be deducted from a measurement from corneal epithelium to the anterior lens surface, made with attachment No II (method A). Often ophthalmologists use the measurement made from the corneal endothelium to the anterior lens surface, using only attachment No II (method B), which is a simpler and faster method. This study examined agreement between methods A and B. Methods: Two studies were conducted independently by each author. PHA measured 127 (27 men, 100 women; mean age, 66.9 years) consecutive Danish patients referred for evaluation because of possible angle closure. RRB measured 109 subjects (30 men, 79 women; mean age, 61.3 years) consecutively from a population based glaucoma survey in Rom Klao, Thailand. Results: Using method A, mean ACD was 1.97 mm (SD 0.29) in the Danish study and 2.59 mm (SD 0.27) in the Thai study. ACD measured with method B was significantly (p< 0.001 ) deeper than method A in both studies (Danes: difference =0.118 (95%CI: 0.109 to 0.127); Thais: difference=0.166 mm (95%CI: 0.158 to 0.174)). With an increase in ACD of 1 mm, the methodological difference increased by 0.052 mm (regression formula: difference (B-A)=0.0667 ×mean ACD -0.0148; R2=0.31). This positive correlation did not differ significantly between the two studies. Conclusions: The relevance and importance of estimating ACD as a risk factor in primary angle closure glaucoma suspects and patients has been repeatedly emphasised. This is the first empirical study to quantify the difference in ACD using these two methods in two samples, one clinic based (angle closure suspects) and the other population based. The size of the methodological difference has a level that corresponds to the age reduction of ACD per decade, or to about 6%of ACD in a given eye. These findings highlight the importance of clinicians recognising that these two methods will give different results and recommend that one should standardise ACD measurements using the Haag-Streit optical pachymeter.

Study on the Surface Modification of Hydrophobic Polyacrylate Intraocular Lens

In this study, the polyacrylate intraocularr lens is irradiated by argon ion which can produce free radicals. In order to obtain better hydrophilic and lower platelets adhesion, monomer vinyl pyrrolidone (NVP) is grafted onto the hydrophobic polyacrylate intraocular lens surface in a certain reaction conditions. Specific changes in intraocular lens are detected by static contact angle (CA), scanning electron microscope (SEM) and light transmittance. The results show that this surface modification can greatly improve its hydrophilic character and surface formation.

Shape-controlled syntheses of rhodium nanocrystals for the enhancement of their catalytic properties

Rhodium （Rh） is a critical component of many catalysts for a variety of chemical transformation processes. Controlling the shape of Rh nanocrystals offers an effective route to the optimization of their catalytic performance owing to a close correlation between the catalytic activity/selectivity and the surface atomic structure. It also helps to substantially reduce the loading amount and thus achieve a sustainable use of this scarce and precious metal. In this review article, we focus on recent progress in the shape-controlled synthesis of Rh nanocrystals with the goal of enhandng their catalytic properties. Both traditional and newly- developed synthetic strategies and growth mechanisms will be discussed, including those based on the use of surface capping agents, manipulation of reduction kinetics, control of surface diffusion rate, management of oxidation etching, and electrochemical alteration. We also use two examples to highlight the unique opportunities offered by shape-controlled synthesis for enhancing the use of this metal in catalytic applications. The strategies can also be extended to other precious metals in an effort to advance the production of cost-effective catalysts.

An approach to calculate surface effects of polyhedron nanocrystals and its application in silicon nanowires

A stretch-release strategy is proposed to analyze the problem of surface energy-induced stress fields in nanocrystals,which is resolved into a stretch sub-problem and a release sub-problem using the superposition principle.The surface effect of silicon nanowires with hexagonal cross-sections is analyzed by the proposed method.The severe stress concentration near the triple junctions of the wire surfaces and the large shear stress on the plane{111}is quantified,which provides a solid mechanical explanation for the kink phenomena in growth transition from direction〈111〉to〈112〉observed in experiments.Different from the conventional view of negligible surface effect for bulk material,we found that there exists a size-independent part of the surface effect on the stress in the order of tens or hundreds of mega Pascal,which corresponds to the stretch-induced biaxial stress in the surface layer and the shape influence of the geometry of nanocrystals.This size-independent part could well explain the size-independent kinking phenomenon during the growth of silicon nanowires.