用于牙科复合树脂的具有固位力外形的无机填料的研究

本文介绍了一类微细的复合式无机填料。由于具有特殊的表面结构，这类填料与复合树脂中的树脂基质之间有良好的结合力，因此称之为“具有固位力外形的无机填料”。用此类填料配制的试验性复合树脂，不仅其磨耗性能有明显的改善，而且其它机械性能也有不同程度的提高。     

纤维/颗粒增强聚乳酸骨折内固定复合材料

现将骨折内固定材料的发展史，传统骨折内固定材料的不足之处，以及开发可吸收骨折内固定材料的意义作一综述。介绍了聚乳酸作为可吸收内固定材料的优异性能，及其复合材料的特点，并比较了以聚乳酸为基体的各种内固定复合材料的成型工艺和机械力学强度。     

New Insights into Lamellar Twisting in Transcrystalline Polyethylene

Summary: The morphology of the transcrystalline layer grown by nucleating high density polyethylene on fibers of ultra high molecular weight polyethylene was investigated by microbeam synchrotron X‐ray diffraction. Scanning with a 2 micron step size, it was possible to determine that near the fiber surface, the polymer chains of the transcrystalline layer are oriented at an angle of approx. 41° with respect to the fiber axis. This is consistent with the lamellar fold surface (the {201} plane) being close to perpendicular to the fiber axis. The X‐ray data support gradual twisting of the lamellae about the growth direction (the orthorhombic crystallite b‐axis) at a rate of ～0.85° per micron of radial distance from the fiber surface.

Polarized light micrograph of the transcrystalline layer in a PE/PE composite. The width of the fiber is approximately 20 μm.     

Curing efficiency and ocular hazards of dental photopolymerization sources

The spectral distributions of a range of dental photocuring sources were measured at the exit window and at a distance of 10 cm. The former enabled the evaluation of a newly proposed photocuring efficiency index which correlates well with the depth of cure of the photopolymerized resins, thus providing a basis for the comparison of different photocuring sources. The spectral irradiante of the sources obeyed the inversesquare law, allowing a comparison with the ACGIH threshold limit values. According to these criteria, no ocular hazard is posed to the patient or clinician by u.v.-A or u.v.-B radiation nor to the patient by the visible light when momentarily exposed to the sources. Similarly the ACGIH criterion indicates that the clinician does not risk chorioretinal injury provided the exposure is restricted to less than 140 s in a 3 h period.     

Structure and properties of methacrylate based dental restorative materials

The chemistry and structure of the dimethacrylate resins and the nature of the filler systems in dental composite resins are reviewed in relation to their influence on the setting behaviour, dimensional stability, aesthetics, fracture behaviour and adhesive potential. It is clear that a deeper understanding of the structure of the polymeric matrix and the mechanism of clinical wear is required. As a result of ongoing research in this area and with the development of dentine adhesives, the future prospects of composite resins are encouraging.     

Evaluation of endocrine disrupting activity of plasticizers in polyvinyl chloride tubes by estrogen receptor alpha binding assay

Polyvinyl chloride (PVC) tubing is an indispensable medical material for extracorporeal circulation therapy. However, di(2-ethylhexyl)phthalate (DEHP), a suspected endocrine disruptor, can be eluted from PVC, suggesting that an alternative material that does not contain DEHP is needed for clinical applications. First, we evaluated the endocrine disrupting risks of the plasticizers contained in PVC tubes by investigating their binding affinities for the human estrogen receptor alpha (ERα). Our results revealed that, while DEHP has some binding affinity for ERα, neither epoxidized soybean oil nor tris(2-ethylhexyl)trimellitate (an alternative to DEHP) has any affinity for ERα. Second, we evaluated the endocrine disrupting risks of a tube made of newly developed plasticizer-free (PF) materials. We confirmed the presence of DEHP and detected several unidentified substances in plasma stored within the PVC tube. This plasma's competitive binding affinity for ERα was significantly higher than that of control plasma (P < 0.01). In contrast, the profile of plasma stored in the PF tube was similar to that of the control, both in terms of high-performance liquid chromatography chromatograms and competitive binding capacity for ERα, suggesting that the PF tube is biocompatible and is useful for reducing the elution of substances capable of binding to ERα. Presented in part at the 42nd Congress of the Japanese Society for Artificial Organs, October 5–7, 2004, Tokyo, Japan     

用于预防术后粘连的可吸收高分子材料研究进展

粘连是结缔组织纤维带与相邻的组织或器官结合在一起而形成的异常结构；其经常在妇产科、心胸外科和脊柱外科手术后出现。粘连是引发术后并发症的主要原因之一。在目前预防粘连的诸多方法中，采用高分子材料作为隔离物是一种有效的途径。本综述了近年来用于预防粘连的各种可吸收高分子材料，其中包括壳聚糖、聚乙二醇、透明质酸、纤维素等。并且介绍了经过化学改性、物理共混、表面接枝等方法获得的许多新型聚合物。这些材料可以制成溶液、薄膜、凝胶等不同形式使用；而且既可以单独使用，也可与抗粘连药物结合使用。     

Anti-microbial active composite nanoparticles with magnetic core and photocatalytic shell: TiO2-NiFe2O4 biomaterial system

Reverse micelle and chemical hydrolysis techniques have been successfully combined to synthesize composite nanoparticles consisting of a photocatalytic shell of titania and a magnetic core of nickel ferrite. The nature of titania shell, i.e. anatase or brookite, depends on the TiO₂ and NiFe₂O₄ molar ratio. The work presented here describes the photocatalytic and anti-microbial activity of the composite nanoparticles together with the magnetic characteristics of the nickel ferrite core. The TiO₂-coated NiFe₂O₄ nanoparticles retain the magnetic characteristics of uncoated nanocrystalline nickel ferrites (superparamagnetism; absence of hysteresis, remanence and coercivity at 300 K) encouraging their application as removable anti-microbial photocatalyst nanoparticles that can be extracted from the sprayed surface (human body or environment) after exposure.     

定制化胫骨平台系统的构建及应用

为解决传统人工胫骨平台假体个体匹配性差，结构强度与生物活性难统一等问题，提出了定制化复合增强型人工胫骨平台系统的设计制造方法。采用解剖学建模技术设计出外形匹配，内含三维网状构架的复合假体模型，利用快速成型技术制造出假体的树脂原型，并分别通过精密铸造和粉末烧结技术制造出钛合金胫骨平台和大段多孔陶瓷人工骨。结果显示，该方法能快速而精确地制造出形状复杂的人工胫骨平台系统，是实现假体定制化制造的有利保证；通过将金属假体和多孔陶瓷人工骨复合，解决了载重部位大段骨缺损的修复问题。临床应用表明，该假体能与对侧关节匹配运动，通过将机械重建与生物重建相结合可实现受损关节的功能重建。     

同种异体大鼠耳廓移植模型的建立及意义

目的建立同种异体大鼠外耳廓移植模型,进行异体复合组织移植免疫的实验研究.方法以Lewis大鼠为供体、BN大鼠为受体,应用显微外科技术,进行吻合血管的全耳廓异体移植,观察移植耳排斥反应的大体表现及组织学特征.结果20只受体动物移植术后全部存活,吻合血管即刻通畅率为100%,移植耳廓呈现典型的免疫排斥反应过程,平均存活时间为(7.8±1.7)d.结论大鼠外耳廓移植是进行异体复合组织移植免疫研究良好的动物模型.