毛细管区带电泳法测定酒石酸唑吡坦片的含量及降解产物

目的 :采用毛细管区带电泳色谱法 (CZE)测定酒石酸唑吡坦的含量 ,并对其中的降解产物进行控制。方法 :采用CZE以 0 .0 3mol·L-1的磷酸盐缓冲液 (pH5 .0 )做运行液 ,运行电压 :16kV(运行电流 :35～ 4 5 μA) ;进样时间 :10s;检测波长 2 14nm。结果 :酒石酸唑吡坦在 2 5～ 2 5 0mg·L-1的范围内呈良好的线性关系 ,相关系数为r=0 .9995。平均回收率为 10 1.2 5 % (n=5 ) ,RSD为 0 .80 %。酒石酸唑吡坦与降解产物分离良好。结论 :本方法简便、快速、准确     

Evaluation of the inner-surface morphology of an artificial heart by acoustic microscopy

The total artificial heart (TAH) is being developed for permanent replacement of the natural heart instead of heart transplantation. The need for detecting the material fatigue in the TAH is increasing in order to guarantee long-term use. In this study, the inner surface morphology of the TAH was evaluated by a specially developed scanning acoustic microscope (SAM) system operating in the frequency range of 100-200 MHz. The inner sac of our TAH consisted of polyvinylchloride coated with polyurethane, and the SAM investigations were performed before and after the implantations in goats. The amplitude images of the SAM demonstrated protein adhesion on the inner surface of the TAH after the animal experiment, and the phase images showed distortion of the wall with spatial resolution of 0.2 microm. These results suggest the feasibility of a high-frequency ultrasound for evaluating the material fatigue of TAH.     

生物医用材料现状和发展趋势

本文综述了生物医用材料产业的现状，总结了生物医用材料发展历程，指出了生物医用材料的发展方向。第三代生物医用材料应兼具生物活性和降解两种性能，在植人体内后可促进机体的再生能力．从而达到治疗效果。以生物医用材料为支架的组织工程可复制“组织”和“器官”，为再生医学的崛起开辟了道路，也为生物医用材料的发展提出了更高的要求，并且拓展了更大的发展空间。     

花青素类天然色素的光降解比较

目的 从天然产物中提取黑米、苋菜红、葡萄红这三种花青素类色素，并比较它们的光稳定性。方法 在统一的环境条件下，使用相同的辐射光源、照度，在近似相同的初始吸光度值下，对这三种色素的光稳定性进行比较研究。结果 花青素类天然色素在白炽灯下较为稳定，而在高压汞灯照射下，光降解速度明显加快。随着照度的增大，花青素类色素的光降解速率也增大，但光降解速率常数的改变和照度之间不存在线性对应关系。结论 黑米天然色素的光稳定性优于苋菜红和葡萄红天然色素。     

单源双能量CT扫描单能谱成像技术基物质图像在痛风结节中的应用

目的探讨单源双能量CT扫描单能谱成像技术基物质图像在痛风结节诊断中的应用价值。方法选取本院2017年1月至2019年1月收治的77例高度怀疑痛风患者,均进行单源双能量扫描及尿酸基图和钙基图的分拆、重建,同时结合常规能量扫描进行诊断。以美国风湿病协会制定的痛风诊断标准为基准,计算单源双能量CT诊断痛风结节的敏感度、特异度与准确率。结果根据美国风湿病协会制定的痛风诊断标准,77例患者中57例患者确诊为痛风结节。共56例患者经单源双能量CT扫描检测到痛风结节,其中11例为单关节受累,45例为多关节受累。单源双能量CT诊断痛风的敏感度为91.23%,特异度为80.00%,准确率为87.18%;常规CT诊断痛风的敏感度为77.19%,特异度为60.00%,准确率为72.73%。单源双能量CT诊断痛风的敏感度、准确率显著高于常规CT(P<0.05)。单源双能量CT共检出痛风结节131处,直径0.1~14.7cm;常规CT共检出痛风结节104处,直径0.4~14.7cm,0.1~0.3cm痛风结节未能显示。结论单源双能量CT扫描操作简单、费用低,可利用单能谱成像技术基物质图像上的结晶标记颜色鉴别尿酸和非尿酸结晶沉积,痛风结节诊断的敏感度与准确率较高,且可检出较小痛风结节,值得在痛风的临床诊断中推广应用。     

Subcutaneous Tissue Mechanical Behavior is Linear and Viscoelastic Under Uniaxial Tension

Subcutaneous tissue is part of a bodywide network of “loose” connective tissue including interstitial connective tissues separating muscles and surrounding all nerves and blood vessels. Despite its ubiquitous presence in the body and its potential importance in a variety of therapies utilizing mechanical stretch, as well as normal movement and exercise, very little is known about loose connective tissue's biomechanical behavior. This study aimed to determine elastic and viscoelastic mechanical properties of ex-vivo rat subcutaneous tissue in uniaxial tension with incremental stress relaxation experiments. The elastic response of the tissue was linear, with instantaneous and equilibrium tensile moduli of 4.77 kPa and 2.75 kPa, respectively. Using a 5 parameter Maxwell solid model, material parameters μ₁ = 0.95 ± 0.24 Ns/m and μ₂ = 8.49 ± 2.42 Ns/m defined coefficients of viscosity related to time constants τ_1M = 3.83 ± 0.15 sec and τ_2M = 30.15 ± 3.16 sec, respectively. Using a continuous relaxation function, parameters C = 0.25 ± 0.12, τ_1C = 1.86 ± 0.34 sec, and τ_2C = 110.40 ± 25.59 sec defined the magnitude and frequency limits of the relaxation spectrum. This study provides baseline information for the stress-strain behaviors of subcutaneous connective tissue. Our results underscore the differences in mechanical behaviors between loose and high-load bearing connective tissues and suggest that loose connective tissues may function to transmit mechanical signals to and from the abundant fibroblasts, immune, vascular, and neural cells present within these tissues.     

阿奇霉素有关物质测定方法的优化分析

目的采用色谱分析法对阿奇霉素相关物质的进行测定,探讨测定方法的优化。方法采用相色谱系统仪器、岛津Class-10Avp系统完成测定,色谱柱为SHISEIDO CAPCELL PAK C18 MG,规格为5μm,250mm×4.6mm。流动相为磷盐酸缓冲液,以0.05mol/L的磷酸氢二钾溶液,以浓度为20%的磷酸调节,直至pH值为8.2;色谱纯试剂乙腈为45∶55;色谱柱温度为30℃;流速为每分钟10mL;检测波长为210nm;进样量为50μL。结果溶液浓度为10~1000μg/mL的范围内的线性关系,结果表明线性关系良好。方法的最低检出限为100ng,r=0.9999。结论本次研究所采用的测定方法能够有效测定阿奇霉素中的相关物质,具有良好的分离性与浓度峰面线性关系。     

Effect of Isomorphous Substitution on the Thermal Decomposition Mechanism of Hydrotalcites

Hydrotalcites have many important applications in catalysis, wastewater treatment, gene delivery and polymer stabilization, all depending on preparation history and treatment scenarios. In catalysis and polymer stabilization, thermal decomposition is of great importance. Hydrotalcites form easily with atmospheric carbon dioxide and often interfere with the study of other anion containing systems, particularly if formed at room temperature. The dehydroxylation and decomposition of carbonate occurs simultaneously, making it difficult to distinguish the dehydroxylation mechanisms directly. To date, the majority of work on understanding the decomposition mechanism has utilized hydrotalcite precipitated at room temperature. In this study, evolved gas analysis combined with thermal analysis has been used to show that CO₂ contamination is problematic in materials being formed at RT that are poorly crystalline. This has led to some dispute as to the nature of the dehydroxylation mechanism. In this paper, data for the thermal decomposition of the chloride form of hydrotalcite are reported. In addition, carbonate-free hydrotalcites have been synthesized with different charge densities and at different growth temperatures. This combination of parameters has allowed a better understanding of the mechanism of dehydroxylation and the role that isomorphous substitution plays in these mechanisms to be delineated. In addition, the effect of anion type on thermal stability is also reported. A stepwise dehydroxylation model is proposed that is mediated by the level of aluminum substitution.     

Localized Exponential Time Differencing Method for Shallow Water Equations: Algorithms and Numerical Study

In this paper, we investigate the performance of the exponential time differencing (ETD) method applied to the rotating shallow water equations. Comparing with explicit time stepping of the same order accuracy in time, the ETD algorithms could reduce the computational time in many cases by allowing the use of large time step sizes while still maintaining numerical stability. To accelerate the ETD simulations, we propose a localized approach that synthesizes the ETD method and overlapping domain decomposition. By dividing the original problem into many subdomain problems of smaller sizes and solving them locally, the proposed approach could speed up the calculation of matrix exponential vector products. Several standard test cases for shallow water equations of one or multiple layers are considered. The results show great potential of the localized ETD method for high-performance computing because each subdomain problem can be naturally solved in parallel at every time step.