Study on Biotribological Behavior of the Combined Joint of CoCrMo and UHMWPE/BHA Composite in a Hip Joint Simulator

UHMWPE composites reinforced with Bovine Bone Hydroxyapatite(BHA)in different contents were prepared by heatpressing formation method.A hip joint wear simulator was used to investigate the biotribological behavior of UHMWPE/BHAcomposite acetabular cups against CoCrMo alloy femoral heads in bovine synovia lubrication at 37±1 ℃.It was found that theaddition of BHA powder to UHMWPE can improve the hardness and creep modulus of UHMWPE/BHA composites,anddecrease their wear rates under bovine synovia lubrication.When the content of BHA filler particles was up to 30 wt%,UHMWPE/BHA composites demonstrated the well design performances of the surface and biotribological properties.Fatigue,ploughing and slight adhesive wear were the main wear mechanisms for UHMWPE and its composites.In addition,the sizes ofwear particles became larger with an increase in BHA powder addition.These results suggest that BHA filler is a desirablecomponent to increase the wear resistance of UHMWPE/BHA composites for biomedical applications.     

二氢青蒿素对超高分子量聚乙烯颗粒诱导的巨噬细胞源性炎性因子释放的影响

目的:研究二氢青蒿素(Dihydroartemisinin,DHA)对超高分子量聚乙烯(Ultra highmolecularweightpolyethylene,UHMWPE)颗粒诱导的小鼠巨噬细胞系RAW264.7细胞源性炎性因子释放的影响。方法:建立UHMWPE颗粒诱导的小鼠巨噬细胞系RAW264.7细胞源性炎性因子释放模型;施加不同浓度的二氢青蒿素观察药物对细胞的影响,酶联免疫分析法(Enzyme-linked immuno sorbent assay,ELISA)检测细胞培养液上清中TNF-α,IL-1β,IL-6和IL-10含量,MTT法检测细胞毒性反应。结果:酶联免疫分析方法结果表明,二氢青蒿素可以显著抑制由UHMWPE颗粒诱导的小鼠RAW264.7细胞促炎细胞因子TNF-α,IL-1和IL-6的表达,并显著促进抗炎因子IL-10的释放,其效应具有剂量依赖性。结论:二氢青蒿素具有显著的抗炎作用,可以抑制UHMWPE颗粒诱导的巨噬细胞炎症反应,其在预防人工关节置换术后假体无菌性松动的药物治疗方面具有潜在的作用。     

透明质酸溶液的流变性能初步研究

透明质酸是一种酸性粘多糖,其特有的粘弹性使其广泛应用于眼科手术等医药领域。使用高级流变扩展系统研究浓度对于透明质酸溶液流变性能的影响。结果表明,透明质酸溶液的粘度随剪切速率的增加而减小。在任何剪切速率作用下,粘度总是与浓度呈正相关。而随着浓度的增加,溶液粘性与弹性频率交叉点降低。     

酯酶产生菌的分离与酶学性质研究

从餐馆附近下水道收集到的土壤中分离获得6株酯酶产生菌,其中S2菌株活性最高,从其形态特征、生理生化试验以及16S rRNA序列分析等方面,初步鉴定S2菌株为假单胞属(Pseudomonas sp.)。对该菌株的部分酶学性质进行了研究,发现该菌株所产的酯酶最适反应温度为40℃,最适反应pH为8.0;且该酯酶在温度为60℃以下和pH 7.0～10.0具有良好的稳定性。     

蚯蚓超氧化物歧化酶理化性质的研究

从蚯蚓中提取超氧化物歧化酶(Superoxide Dismutase简称SOD),经硫酸铵分级沉淀分离、透析除盐后测定SOD活性得知:50~70%饱和度硫酸铵沉淀的SOD活性最高,比活性也最高;蚯蚓体内此酶在35~40℃之间表现出最高活性;最适pH值为7.8~8.2;提取蚯蚓SOD的最适提取液体积应为蚯蚓鲜重的4倍(v/w)。     

鲤鱼鱼皮胶原蛋白的提取及其性质研究

首先对鲤鱼鱼皮的成分进行了研究,通过凯氏定氮、索式抽提、高温灰化、直接干燥法测定了鱼皮的蛋白质、脂肪、灰分、水分含量。通过粘度测定法得到鱼皮胶原蛋白的变性温度为28℃左右;紫外可见光谱扫描的结果证明鱼皮胶原蛋白在228 nm有一最大吸收峰;SDS-PAGE电泳初步确定鱼皮胶原蛋白是I型胶原蛋白;酶解实验进一步证实了鱼皮同鱼鳞、鱼骨的胶原蛋白在结构上具有很大的相似性。     

PLGA的不同组成对支架材料性能的影响研究

研究PLGA的不同组成对支架材料的力学性能、降解性能和生物学性能的影响。采用溶液浇注/颗粒沥取法制备出不同组成的PLGA多孔支架,对支架的力学性能和降解速率进行考察,同时将人真皮成纤维细胞接种于不同组成的PLGA支架材料上,培养不同时间后,检测细胞的粘附率和增殖率,以及细胞产生的总胶原含量,并通过扫描电镜观察支架上的细胞形态。结果显示,随PLA比例的增加,支架的力学强度增加,降解速率降低,但都不是线性变化。70:30比例的支架,拉伸强度最高,而70:30和80:20两种比例的支架,其降解速率没有显著性差异。PLGA不同组成的支架,均具有良好的细胞相容性,成纤维细胞粘附率和增殖率在三种比例的支架上没有显著性差异,细胞在支架表面生长良好,分泌大量的细胞外基质,细胞基本铺满整个支架。本文研究发现,PLGA的组成对支架力学性能、降解性能和生物学性能有细小但显著的影响,这将对组织构建选用PLGA支架材料提供有益的帮助。     

温度对胸腺激素理化性质和生物活性的影响

为探讨胸腺激素耐受的最高温度,将胸腺因子Ｄ、胸腺素和胸腺肽加热至１２１℃、１２５℃、１３０℃,直至１９０℃１５ｍｉｎ。结果：加热１４０℃以下１５ｍｉｎ,其色泽、澄明度、紫外吸收峰、旋光度、ＰＨ值、蛋白质含量、相对比移值和活性玫瑰花形成率,与未加热样品比较,均无明显变化;加热至１５０℃以上,上述指标除紫外吸收峰外,余均显著改变。结果表明,胸腺因子Ｄ、胸腺素和胸腺肽能耐受１４０℃１５ｍｉｎ。     

海洋来源琼胶酶的分离纯化及酶学性质研究

采用Vibiro sp.ZC-1发酵制备琼胶酶,粗酶液经过中空纤维柱浓缩、硫酸铵沉淀、DEAE-阴离子交换层析,得到一个电泳纯的琼胶酶组分Aga ZC-1,其分子质量约为45k Da,比活力为114.613U/mg。对Aga ZC-1进行酶学性质分析,结果表明,其最适反应p H为7.0,在p H为5.0~9.0时保温1h仍能保持80%以上的酶活力;最适反应温度为50℃,在45℃条件下保温1h酶活力保持在60%以上。在高浓度(5mmol/L)下,Fe~(3+)、Cu~(2+)、Sn~(2+)和Zn~(2+)能完全抑制琼胶酶的活性,在低浓度(1mmol/L)下,Cu~(2+)、Ba~(2+)、Na~+、Zn~(2+)、Ag~+、Sr~(3+)、K+对琼胶酶活性具有明显抑制作用。琼胶酶的动力学参数K_m和V_(max)分别为0.538mg/ml和6.33μmol/(L·min),对琼胶底物具有高度专一性,降解产物主要为新琼四糖和新琼六糖。     

一株耐热脂肪酶产生菌的筛选及酶学性质研究

从云南省富油地采取了60份土样中,利用透明圈法筛选出一株耐热脂肪酶产生菌。对其酶学性质和发酵条件进行了研究,酶学性质表明,该酶最适作用温度为50℃,最适pH6.0,在pH3.0-8.0范围内稳定,在60℃保温60 min酶活还保留70%;70℃保温60 min残余50%;具有良好的热稳定性;不同金属离子有不同的作用,Ca+,K+对酶有激活作用,Fe3+、Pb2+、Mn2、Cu2+、Al3+、Zn2+对酶活有抑制作用。EDTA对酶影响不大。产酶最佳条件为:MgSO4.7H2O 0.05 g,K2HPO40.1 g,CaCO30.25 g,可溶性淀粉2.5 g,大豆粉2.5 g,装液量50 mL。这株细菌通过培养基优化酶活达到20.3 U/mL。     

云南基孔肯雅病毒生物学性状的研究

本文对分离自云南的基孔肯雅病毒进行了生物学特性研究。实验证明基孔肯雅病毒对乳鼠有强而稳定的致病性,对C6/36,BHK21及Vero细胞有致病变作用,能与鹅和鸽红细胞凝集,最适pH5.75。电镜观察病毒呈圆形,有膜,外径66.8nm,内径47.7nm。交互血凝抑制及中和试验表明,云南毒株之间或与国外原株在抗原性上无明显差别,为同一血清型,并与同亚组病毒反应较弱,与其它虫媒病毒无交叉。本文还讨论了云南株与国外原株在某些生物学特性方面的异同。     

洛美沙星对Bloom综合征解旋酶生物学特性影响的机理研究

Bloom综合征解旋酶(BLM)是RecQ家族DNA解旋酶中的一个重要成员,参与了DNA复制、修复、转录、重组以及端粒的维持等细胞代谢过程,在维持染色体的稳定性中具有重要作用.BLM解旋酶的突变可导致Bloom综合征.Bloom综合征是一种罕见隐性常染色体遗传疾病,患者遗传不稳定,并易患多种类型癌症.洛美沙星(LMX)可以抑制细胞内多种酶,并通过结合DNA干扰DNA代谢,从而治疗多种疾病,但是其具体的作用机理还未完全清楚.运用荧光偏振技术和自由磷检测技术,研究了LMX对BLM642～1290解旋酶DNA结合活性、解链活性和ATP酶活性的影响.运用荧光及紫外吸收光谱法研究了LMX与解旋酶结合的结合常数、结合位点数、作用力类型、结合距离等参数.结果表明,LMX与解旋酶之间能自发进行反应,两种分子有一个结合位点,通过静电引力和疏水作用力形成稳定的BLM-LMX复合物,且解旋酶的内源荧光被LMX静态猝灭,主要原因是非辐射能量转移.在这一过程中,LMX能抑制解旋酶的解链活性和ATP酶活性,而促进解旋酶的DNA结合活性.LMX对BLM解旋酶生物学活性影响的机理可能是LMX使解旋酶通过别构机制影响其ATP酶活性,并使酶的构象维持在较低解链活性的状态,通过抑制ATP催化水解与解链过程的偶联和阻止解旋酶的易位,从而抑制其解链.LMX能够促进解旋酶的DNA结合活性,可能是因为其C-6和C-7上的取代功能基团可以增加酶活力,以及增强药物、酶和DNA的结合,从而形成药物-酶-DNA复合物.这些结果为研究以DNA解旋酶为药物靶标的分子机理和理解喹诺酮类药物的作用机理奠定相关理论基础.     

升血汤促进辐射损伤小鼠造血与免疫功能恢复的实验研究

本文研究了中药升血汤对辐射损伤小鼠造血与免疫功能恢复的促进作用,结果证明,升血汤能显著地增加辐射损伤小鼠外周血中各类血细胞数以及骨髓及脾脏中的有核细胞数,明显促进小鼠巨噬细胞,Ｔ及Ｂ淋巴细胞功能的恢复,表明升血汤可以明显促进辐射损伤小鼠造血与免疫功能的恢复。     

Instrumented Indentation Investigation on the Viscoelastic Properties of Porcine Cartilage

Articular cartilage lubricates the contact surfaces in human joints and provides a shock-absorbing effect which protects the joint under dynamic loading. However, this shock-absorbing effect is gradually reduced as the result of normal wear, tear and aging-related cartilage loss. Thus, with the increasing average human life expectancy, the issue of joint health has attracted significant interest in recent decades. In developing new materials for the repair or regeneration of damaged articular cartilage, it is essential that the difference in the mechanical properties of healthy and damaged cartilages is well-understood. In the present study, the hardness and Young＇s modulus of damaged and healthy porcine articular cartilage samples are evaluated via a quasi-static nanoindentation technique. A dynamic mechanical analysis method is then applied to determine the viscoelastic properties of the two samples. The results presented in this study provide a useful insight into the mechanical properties of articular cartilage at the mesoscale, and therefore fill an important gap in the literature.     

药用微生物辐照诱变研究进展

常规的诱变育种方法主要是利用紫外线、激光、γ射线、中子等对微生物药物菌种进行辐照诱变,效果显著。离子束辐照微生物诱变育种在离子束生物学效应的研究中起步较晚,但其作为一种集物理诱变和化学诱变为一体的诱变育种新方法,将在辐照诱变育种中发挥重要作用。本文综述了近年来微生物药物研究与开发的动态,简要叙述微生物菌种选育的辐照诱变效应、作用机制及其在实践中的应用。     

天花粉中三个同工凝集素的分离纯化及其生物学性质研究

运用阴离子交换层析从亲和纯的天花粉凝集囊中分离得到三个同工形式的凝集素,它们都具有结合半乳糖的能力,都能与天花粉凝集大的抗血清形成免疫沉淀线,并且其它各方面的性质如疏水结合能力也相仿。对它们生物学性质的检测,发现它们都能杀伤黑色素瘤细胞,但缺乏抑制无细胞蛋白质生物合成的能力。另外,对植物中同工形式凝集大的存在进行了讨论。     

Influence of Bio-Lubricants on the Tribological Properties of Ti6Al4V Alloy

Titanium alloy is one of the best materials for biomedical applications due to its superior biocompatibility, outstanding corrosion resistance, and low elastic modulus. However, the friction and wear behaviors of titanium alloys were sensitive to the environment including lubrication. In order to clarify the wear mechanism of titanium alloy under different lubrications including deionized water, physiological saline and bovine serum, the friction and wear tests were performed between Ti6Al4V plates and Si₃N₄ ball on a universal multi-functional tester. The friction and the wear rate of titanium alloy were measured under dry friction and three different lubrication conditions. The worn surfaces were examined by scanning electron microscopy. The results revealed that under the dry friction, the wear resistance of titanium alloy was the worst since the wear mechanism was mainly the combination of abrasive wear and oxidation wear. It was also found that Ti6Al4V alloy had low friction coefficient and wear rate under three lubrication conditions, and its wear mechanism was adhesive wear.     

青橄榄总黄酮提取工艺及部分性质研究

目的：以青橄榄为原料研究提取分离黄酮类化合物的方法与条件,建立最佳提取工艺。方法：采用醇提法,通过单因素试验考察浸提溶剂浓度、浸提温度、浸提时间等三个因素对青橄榄中黄酮类化合物提取效率的影响,同时采用不同显色方法及紫外、红外测定其性质。结果：在单因素的基础上,通过正交试验L9（34）,得三因素中乙醇浓度的影响最大,并初步判断了提取物的性质。结论：青橄榄中黄酮类化合物最佳提取工艺为：乙醇浓度60%,浸提温度70℃,浸提时间120min,提取率达19.87mg/g。另外初步判断提取物中可能含有查尔酮类化合物。     

Effects of Plasma Nitriding on Microstructure and Tribological Properties of CoCrMo Alloy Implant Materials

##正## Medical forged CoCrMo alloy was treated by plasma nitriding process.The microstructures were characterized by 3Dprofiler,SEM and XRD.The tribological properties were investigated under lubrication of 25% bovine serum solution.Resultsshow that plasma nitriding is a promising process to produce thick,hard,and more wear resistant layers on the surface of CoCrMoalloy.All nitrided samples showed an important increase in the surface hardness due to the formation of harder CrN andCr_2N phases with compact nano-crystalline structures.The typical hardness values of HV_(0.05) increased almost two times thanuntreated one.Under bovine serum lubrication,at low nitriding temperature the Coefficient of Friction (COF) of nitrided samplewas lower than that of untreated sample,but at high nitriding temperature the COF was almost the same as the untreated one.Compared with the untreated sample,the nitrided samples showed lower wear rates and higher wear resistance under differentnitriding temperatures.The adhesive wear is the main mechanism for untreated CoCrMo alloy and the wear mechanisms ofnitrided ones are the fatigue wear and slight adhesive wear.It is concluded that the improvement of wear resistance is ascribed tothe hard nitride formation of CrN and Cr_2N phases at the nitrided surfaces.     

新型生物降解材料聚己酸内酯的理化性能研究

对聚己酸内酯材料的理化性能测试结果显示其结构为[O-(CH_2)_5-CO-]n,为α-聚酯类聚合物。SEM分析结果为半晶体、线性聚合物。平均分子量为6万。抗压强度为25Mpa,具有力学松弛和蠕变性能。密度为1.13g/cm~3。材料软化点为60～62℃,降低温度至室温后5～15:分钟,样品固化,呈乳白色晶料,证实为热塑性聚合物。材料溶于四氢呋喃、三卤甲烷、甲苯。微溶于丙酮、乙酸。不溶于水和乙醇,可在室温下保存。是一种有广泛应用前景的组织修复材料。