中药特色之一地道药材研究进展

中药材的地道性是中药的特色之一,也是影响中药质量的关键因素。从地道药材的概念、属性及影响药材地道性的因素方面对地道药材研究进展情况进行了探讨分析。     

应用ImageJ程序包进行材料显微组织图像处理、分析和可视化的一种框架(英文)

显微组织图像(例如胞、粒子与晶粒等)的数字图像处理、分割和分析,对于获取显微组织特征的三维信息非常重要。已有数种商用和共享程序包可以用于图像的处理和分析。"ImageJ"即其中之一,其长期广泛采用及其可扩展插件形式已使其成为许多不同应用领域科学家选用的工具。它包含了处理、分割、重建和可视化材料显微结构所需要的几乎所有基本的和最新的功能以及图像分析工具(例如‘Particle Analyzer’,‘3D object counter’,‘3D Roi Manager’),以用于成组粒子的复杂统计处理。虽然它在生物医学研究领域很受欢迎,被认为是一种有用的和有效的开放源码的图像处理与分析软件,但是在材料科学领域对其所知甚少。面向材料学界,本文尤其是那些没有图像处理和分析经验的材料科学与工程专业人员,在简要介绍ImageJ的基础上,提出了将其应用于在三维空间中处理、分割和分析显微组织结构连续切片图像的一个通用框架。     

Influence of core material on fracture resistance and marginal adaptation of restored root filled teeth

Aim To investigate ex vivo the influence of direct placement core materials on the fracture strength and marginal adaptation of root filled maxillary central incisors restored with glass fibre‐reinforced posts, various core materials and all‐ceramic crowns. Methodology Forty‐eight human maxillary incisors were root filled. Posts were placed and teeth restored with composite cores and crowns (n = 8). Six core materials were examined after thermal cyclic and mechanical loading (TCML). Fracture force was determined under static loading. The marginal adaptation at the interfaces between cement‐tooth and cement‐crown were categorized as ‘intact margin’ or ‘marginal gap’ using scanning electron microscopy. Statistical analysis was undertaken with the Mann–Whitney U‐test (α = P ≤ 0.05). Results Median fracture strength varied between 204 N (low viscous experimental core) and 1094 N (Multicore). No difference in fracture resistance was found with varying viscosity of the core material. The layering technique improved the fracture performance (P = 0.059) to a minor degree. Crowns with dedicated core materials (Rebilda 1063 N; Multicore 1094 N) had a significantly higher fracture resistance than crowns with a conventional restorative material (Tetric Ceram 509 N). Significantly poorer marginal adaptation before TCML was found for the layering technique at the tooth–cement interface and for all experimental cores after TCML. At the crown–cement interface significant differences in marginal adaptation could be determined between Multicore‐layered core (P = 0.002) and Multicore‐Rebilda (P = 0.001) after TCML. Conclusions The fracture strength of post and core restorations was dependent on the core material and bonding system. Marginal adaptation was influenced by the method of application of the core material and by TCML.     

Mechanical properties of provisional crown and bridge materials: chemical-curing versus dual-curing systems

OBJECTIVES: This study aimed to investigate the flexural strength (FS) and flexural modulus (FM) of provisional crown and bridge materials at different storage times after mixing using materials with different curing mechanisms (dual-curing vs. self-curing). METHODS: FS and FM of four proprietary materials (Trim, Luxatemp AM Plus, Luxatemp AM Plus Solar and Cool Temp Natural) were tested in a 3-point bending test according to EN ISO 4049:2000 at various times after mixing (37 degrees C dry/water) including thermocycling (5000x, 5-55 degrees C). Mean values of all measurements were calculated and subjected to the Games-Howell test (p=0.05) as well as a regression analysis (p=0.05). A two-way ANOVA (p=0.05) was used to identify the influence of the curing mechanism and chemical nature of the materials used. RESULTS: FS ranged between 11.1 and 24.0 MPa and FM between 82.5 and 548.2 MPa for all tested materials except for the dual-curing material (FS: 82.4 MPa; FM: 2060 MPa) 10 min after mixing. The r2-values, describing the goodness-of-fit of the regression curve for the relation between the mechanical properties and storage time, ranged from 0.701 to 0.979 for the composite based materials and 0.671 to 0.685 for the methacrylate resin. The chemical nature and curing mechanism significantly influenced (p<0.001) the mechanical properties, however, the influence of the curing mechanism disappeared at progressive points in time after mixing comparing Luxatemp AM Plus versus Luxatemp AM Plus Solar. CONCLUSIONS: FS and FM significantly depend on the time after mixing. Composite resin based materials are preferred versus methacrylate resins due to more favourable mechanical properties. If a high mechanical strength is indispensable directly after fabrication, a dual-curing provisional material is recommended.     

内源性显影栓塞材料灭菌稳定性的研究

研究探索内源性显影栓塞材料显影效果的灭菌影响因素,建立适宜的灭菌方法。探讨了湿热灭菌法、辐照灭菌法、膜过滤法对材料的灭菌效果,采用滴定方法检测材料中的碘含量,比较灭菌前后碘含量的变化以对比材料的显影效果。结果表明湿热灭菌法和辐照灭菌法虽然能有效灭菌,但是材料中的碘含量减少较多,降低了材料的显影效果;膜过滤法在有效灭菌的同时对样品中碘含量的基本没有影响,材料的显影效果不变化。内源性显影栓塞材料的最优灭菌方法为膜过滤法。     

电子商务技术在医院医疗器械采购中的应用探讨

本文着重分析了我国医院医疗器械采购的现状、存在的问题,提出了电子商务技术在今后医院医疗器械采购工作中应用的可能性,通过政府利用先进技术搭建合法合理的系统平台,建立基于第三方的虚拟市场,实现医疗器械的集中招标、集中采购、统一定价、医院分别订货、透明交易等功能,以期整合医疗器械生产,经营企业资源,优化供应链管理,减少流通环节,降低采购成本、物流成本,提高交易的透明度,提高整个医疗器械流通运行效率。     

A composite material model for improved bone formation

The combination of synthetic polymers and calcium phosphates represent an improvement in the development of scaffolds for bone‐tissue regeneration. Ideally, these composites provide both mechanically and architecturally enhanced performances; however, they often lack properties such as osteoconductivity and cell bioactivation. In this study we attempted to generate a composite bone substitute maximizing the available osteoconductive surface for cell adhesion and activity. Highly porous scaffolds were prepared through a particulate leaching method, combining poly‐ε‐caprolactone (PCL) and hydroxyapatite (HA) particles, previously coated with a sucrose layer, to minimize their embedding by the polymer solution. Composite performances were evaluated both in vitro and in vivo. In PCL–sucrose‐coated HA samples, the HA particles were almost completely exposed and physically distinct from the polymer mesh, while uncoated control samples showed ceramic granules massively covered by the polymer. In vivo results revealed a significant extent of bone deposition around all sucrose‐coated HA granules, while only parts of the control uncoated HA granules were surrounded by bone matrix. These findings highlight the possibility of generating enhanced osteoconductive materials, basing the scaffold design on physiological and cellular concepts. Copyright © 2010 John Wiley & Sons, Ltd.     

PET/CT设备选型关键技术参数探讨

PET/CT是目前最先进的分子显像设备,具有很高的灵敏度和特异性。从晶体材料和工艺、PET采集方式、PET重建算法、图像融合技术、后处理技术等几个方面,对影响PET/CT性能的关键技术参数进行了细致的分析,为医院决策者引入PET/CT的选型论证提供了重要的参考价值。     

政府购买农村基本公共卫生服务的实践与思考

介绍了河南省武陟县开展购买农村基本公共卫生服务的试点经验和主要做法,就"购买服务+绩效合同管理"这一农村公共卫生服务提供新模式的实施效果进行了深入思考和分析,建议:加强乡、村两级基本公共卫生服务适宜技术培训,规范乡、村两级服务协议内容,强化双向转诊管理,建立农村公共卫生服务管理信息系统,为城乡居民提供规范的、有质量保证的公共卫生服务.