骨组织工程支架材料研究进展*

骨在组织工程中得到了非常广泛、深入的研究.支架材料与许多可降解材料一起也在进行探索性研究.用于骨组织工程的生物材料可以是三维多孔的刚硬材料,也可以是可注射材料.本文从聚合物角度综述了骨组织工程对支架材料的基本要求,用于骨组织工程的可降解生物材料、支架材料的设计和制备技术以及支架材料的表面修饰等方面的研究进展.     

Effects of Bisphenol A and Its Alternatives,Bisphenol F and Tetramethyl Bisphenol F on Osteoclast Differentiation

Bisphenol A (BPA) is a typical environmental endocrine disruptor that exhibits estrogen-mimicking, hormone-like properties and can cause the collapse of bone homeostasis by an imbalance between osteoblasts and osteoclasts. Various BPA substitutes, structurally similar to BPA, have been used to manufacture ‘BPA-free’ products; however, the regulatory role of BPA alternatives in osteoclast differentiation still remains unelucidated. This study aimed to investigate the effects of these chemicals on osteoclast differentiation using the mouse osteoclast precursor cell line RAW 264.7. Results confirmed that both BPA and its alternatives, bisphenol F and tetramethyl bisphenol F (TMBPF), were nontoxic to RAW 264.7 cells. In particular, tartrate-resistant acid phosphatase (TRAP)-positive multinucleated cell staining and activity calculation assays revealed that TMBPF enhanced osteoclast differentiation upon stimulation of the receptor activator of nuclear factor-kappa B ligand (RANKL). Additionally, TMBPF activated the mRNA expression of osteoclast-related target genes, such as the nuclear factor of activated T-cells, cytoplasmic 1 (NFATc1), tartrate-resistant acid phosphatase (TRAP), and cathepsin K (CtsK). Western blotting analysis indicated activation of the mitogen-activated protein kinase signaling pathway, including phosphorylation of c-Jun N-terminal kinase and p38. Together, the results suggest that TMBPF enhances osteoclast differentiation, and it is critical for bone homeostasis and skeletal health.     

高效液相色谱法测定全血中骨碱性磷酸酶的活力

 建立了测定全血中骨碱性磷酸酶(BALP)的高效液相色谱法(HPLC)。色谱柱为SpectraPhysicsODS反相柱,以V(0.01mol/L乙酸,pH4.8)∶V(甲醇)=70∶30的溶液为流动相,流速为0.8mL/min,检测波长为275nm。当BALP的质量浓度为8～200mg/L时,其活性对峰面积呈良好的线性关系(r=0.996),检测限为3ng。该方法简便、快速、可靠,可用于临床测定全血中的BALP。     

The Effect of Physical Activity on the Properties of Bone Tissue

The effect of sports training or lack of physical activity on the properties of bone tissue is investigated. People with normal physical activity, sportsmen, and hypodynamic persons are tested. Ultrasound as a safe and noninvasive method is used. In normal activity and after short-time sports training or bed rest, the maximum ultrasound velocity is observed in the middle part of the tibia diaphysis because this region has the highest bending moment. Long-time sports training (more than seven years) in basketball and freestyle skiing alters the distribution of ultrasound velocity along the tibia: the maximum velocity is found in the distal diaphysis of the tibia due to the existence of high mechanical stresses in this region caused by the intense external impact loads and the calf muscle contraction. The maximum velocity for rowers is in the middle diaphysis or in the region between the proximal and middle diaphysis, since high impact loads are not characteristic of their foot joints. Long-time hypodynamia weakens the distal diaphysis of the tibia due to the lack of naturally occuring high stresses in this part of the bone.     

载荷诱导骨生长的力学细胞生物学机制

骨骼的结构和功能在很大程度上依赖于其所处的力学环境,这一观点已被广为接受．自从Ｗｏｌｆｆ提出其著名的骨转换定律以来,骨生长与载荷间的关系一直是生物力学中一个重要的问题．大量的动物实验均证明二者之间存在明确的关联．然而,载荷诱导骨生长的力学细胞生物学（ｍｅｃｈａｎｏｃｙ－ｔｏｂｉｏｌｏｇｙ）机制仍很不清楚．十余年来体外培养骨骼细胞加载的研究为应力（应变）诱导骨生长提供了一个微观理论框架．目前认为,载荷诱导骨生长的过程可分为四个环节,即：力学耦联、生物化学耦联、胞间信号转导和效应细胞反应．详细阐述了这几个环节,并就今后的研究方向作一讨论．     

含液体松质骨的压缩实验分析

在本文中,假设不含液体松质骨为红弹性体,以及松质骨固液两相结构特性,建立了含液体松质骨的单向压缩本构方程,其形式与三参量线粘弹性体的本构方程相同。并通过拟合实验结果,得到本构方程中有关参数的值。     

我国口腔生物力学研究进展与展望

本文综述了我国口腔生物力学研究现状、研究手段、达到的水平以及临床应用状况、并作了展望。      

网络驱动的未识甲骨字特性及场景语义预测

甲骨学的研究具有重要的文化价值和传承意义,可以极大提高国家的文化自信。未识甲骨字的语义预测是甲骨学研究中最主要的问题,也是传统甲骨学研究中最棘手的问题。现有的计算机技术辅助研究方法无法预测未识甲骨字的语义。利用复杂网络对甲骨文进行了抽象和理解,并对未识甲骨字的场景语义进行预测。首先,以甲骨拓片为基础数据,通过建模构建甲骨字网络;其次,在甲骨字网络之上,分析未识甲骨字的重要性、信息丰富度、闭合性等特性,为预测未识甲骨字的场景语义提供理论依据;最后,根据网络特性和甲骨拓片的上下文语境预测未识甲骨字的场景语义。构建的未识甲骨字特性体系以及预测未识甲骨字的场景语义思路为破译其他未识甲骨字的语义奠定了基础,有助于推动甲骨文考释的进程。     

Ceramics based on double magnesium–sodium phosphates for bone regeneration

The fabrication of ceramics based on double phosphates MgNaPO₄ and Mg₄Na(PO₄)₃ is considered. Volume changes in phase transformations of MgNaPO₄ and Mg₄Na(PO₄)₃ upon thermal treatment in a range of 800–1100 °C and their effect on the microstructure of ceramics are studied.