Empirical Multicomponent Equilibrium and Film-Pore Model for the Sorption of Copper,Cadmium and Zinc onto Bone Char

The adsorption of three metal ions onto bone char has been studied in both equilibrium and kinetic systems. An empirical Langmuir-type equation has been proposed to correlate the experimental equilibrium data for multicomponent systems. The sorption equilibrium of three metal ions, namely, cadmium (II) ion, zinc (II) ion and copper (II) ion in the three binary and one ternary systems is well correlated by the Langmuir-type equation. For the batch kinetic studies, a multicomponent film-pore diffusion model was developed by incorporating this empirical Langmuir-type equation into a single component film-pore diffusion model and was used to correlate the multicomponent batch kinetic data. The multicomponent film-pore diffusion model shows some deviation from the experimental data for the sorption of cadmium ions in Cd-Cu, Cd-Zn and Cd-Cu-Zn systems. However, overall this model gives a good correlation of the experimental data for three binary and one ternary systems.     

Yukmijihwang-Tang Suppresses Receptor Activator of Nuclear Factor Kappa-B Ligand (RANKL)-Induced Osteoclast Differentiation and Prevents Ovariectomy (OVX)-Mediated Bone Loss

Yukmijihwang-tang (YJ) has been used to treat diabetes mellitus, renal disorders, and cognitive impairment in traditional medicine. This study aimed to evaluate the anti-osteoporotic effect of YJ on ovariectomy (OVX)-induced bone loss in a rat and receptor activator of nuclear factor kappa-B ligand (RANKL)-mediated osteoclast differentiation in bone marrow macrophages (BMMs). YJ reduced the formation of tartrate-resistant acid phosphatase (TRAP)-positive multinucleated cells (MNCs) in an osteoclast/osteoblast co-culture system by regulating the ratio of RANKL/osteoprotegerin (OPG) by osteoblasts. Overall, YJ reduced TRAP-positive cell formation and TRAP activity and F-actin ring formation. Analysis of the underlying mechanisms indicated that YJ inhibited the activation of the nuclear factor of activated T cell cytoplasmic 1 (NFATc1) and c-Fos, resulting in the suppression of osteoclast differentiation-related genes such as TRAP, ATPase, H+ transporting, lysosomal 38 kDa, V0 subunit d2, osteoclast-associated receptor, osteoclast-stimulatory transmembrane protein, dendritic cell-specific transmembrane protein, matrix metalloproteinase-9, cathepsin K, and calcitonin receptor. YJ also inhibited the nuclear translocation of NFATc1. Additionally, YJ markedly inhibited RANKL-induced phosphorylation of signaling pathways activated in the early stages of osteoclast differentiation including the p38, JNK, ERK, and NF-κB. Consistent with these in vitro results, the YJ-administered group showed considerably attenuated bone loss in the OVX-mediated rat model. These results provide promising evidence for the potential novel therapeutic application of YJ for bone diseases such as osteoporosis.     

Interfacial Compatibilization into PLA/Mg Composites for Improved In Vitro Bioactivity and Stem Cell Adhesion

The present work highlights the crucial role of the interfacial compatibilization on the design of polylactic acid (PLA)/Magnesium (Mg) composites for bone regeneration applications. In this regard, an amphiphilic poly(ethylene oxide-b-L,L-lactide) diblock copolymer with predefined composition was synthesised and used as a new interface to provide physical interactions between the metallic filler and the biopolymer matrix. This strategy allowed (i) overcoming the PLA/Mg interfacial adhesion weakness and (ii) modulating the composite hydrophilicity, bioactivity and biological behaviour. First, a full study of the influence of the copolymer incorporation on the morphological, wettability, thermal, thermo-mechanical and mechanical properties of PLA/Mg was investigated. Subsequently, the bioactivity was assessed during an in vitro degradation in simulated body fluid (SBF). Finally, biological studies with stem cells were carried out. The results showed an increase of the interfacial adhesion by the formation of a new interphase between the hydrophobic PLA matrix and the hydrophilic Mg filler. This interface stabilization was confirmed by a decrease in the damping factor (tanδ) following the copolymer addition. The latter also proves the beneficial effect of the composite hydrophilicity by selective surface localization of the hydrophilic PEO leading to a significant increase in the protein adsorption. Furthermore, hydroxyapatite was formed in bulk after 8 weeks of immersion in the SBF, suggesting that the bioactivity will be noticeably improved by the addition of the diblock copolymer. This ceramic could react as a natural bonding junction between the designed implant and the fractured bone during osteoregeneration. On the other hand, a slight decrease of the composite mechanical performances was noted.     

多胞材料的力学行为

多胞材料具有独特的力学性质,其工程应用日益增加.人造多胞材料可以分为蜂窝材料和泡沫材料两类.本文介绍了这两类材料在不同载荷条件下力学行为的研究概况.对于某些天然材料(木材和松质骨)的多胞结构及其模型也作了简要介绍.      

生物力学进展和趋向(续)

三、运动关节力学运动关节(diarthrodial joint)的功能在于使动物能灵巧地运动肢体。译成力学术语就是:传递载荷,吸收冲击、振动,承受相当高的应力,且运动时摩擦系数很小。L.L.Malcom曾精细地测量过牛肱关节的摩擦系数,在正应力1—20kg/cm~2的范围内,动摩擦系数为0.0025—0.0040,而最好的工程材料的摩擦系数为0.01—0.05,整整差一个量级。      

骨铅含量应作为人体铅中毒新的生物标记

综述了人体铅含量的危害,血铅检测的局限性以及骨铅检测的必要性和检测技术研究进展。认为国内应该加强相关的研究,早日将骨铅含量作为人体铅中毒新的生物标记。     

微波消解/电感耦合等离子体质谱测定鹿骨粉中微量元素

采用HNO₃-H₂O₂ 微波溶样、电感耦合等离子体质谱法测定了鹿骨粉中的微量元素。在优化的实验条件下,方法的检出限(3σ, n=11)为0.000 6～1.498 ng·mL-1;标准加入回收率为91％～109％,相对标准偏差为1.7％～6.8％。对国家标准物质样品分析的结果与所给参考值吻合。     

铝和铝氟病鸡模型全血骨元素和血清生化骨矿含量骨形态学的相关研究

复制了铝危害和铝氟病鸡模型。将100日龄84只雄性种鸡随机分为7个组,毒物加进配合饲料自由摄食,实验3个月。结果表明,高铝、高氟、高氟铝组在实验3周内全血多种元素和7周内的血清生化物质含量及其相关性便发生显著变化,实验13周性成熟后出现逆转并接近正常。均引骨骼元素含量、骨细胞、骨胶元、骨组织形态、骨矿代谢、骨塑形和骨骼力学机能的病理变化。性成熟后饲料加氟与未加氟各3个组的全血铁、磷、血清钙、GRT才出现分异,并与骨矿代谢动态参数的分异相吻合。表晨本实验性成熟前诸多病变主要是铝危害引起。铝可较长期使全血锌和和骨锌含量下降。全血元素含量和相关性的变化是受机体内环境影响较大的动态变化过程。骨代谢联系着广泛的生物无机化学基础。性成熟后高氟、高氟铝、高铝的危害尚有各自的特点。     

骨铅体内测量系统最佳测量位置的选择

^109Cd K XRF骨铅体内测量系统对体重指数大的对象测量所得的结果误差较大。测量时胫骨在探测器前的位置对测量结果误差的影响很大。采用模拟重指数大的被测对象的大体模,与原来的标准体模在探测器前不同距离时进行测量的对比分析表明,体重指数大的被测对象因其胫骨周围组织层较厚,造成康普顿计数大量增加。若胫骨与探测器的距离太近,仪器不能正常工作,致使X能谱图谱形畸变,得到不正确的结果。因此,在测量时,应保持胫骨在探测器前的距离为25mm,同时,应注意相干散射峰的峰位变化,保持仪器即时显示的死时间30%左右,以保证最后测量结果的精密度和准确度。     

骨粉中磷、钙含量的测定

采用氧瓶燃烧消化骨粉样品,比色法测定其磷含量,络合滴定法测定其钙含量。经实际样品测定,测定磷含量的变异系数≤0.24%,测定钙含量的变异系数≤0.14%。经t检验证明,氧瓶燃烧法消化样品的测定结果与湿灰法无显著性差异。