Synthesis, characterization and osteoconductivity properties of bone fillers based on alendronate-loaded poly(ε-caprolactone)/hydroxyapatite microspheres

A superior drug controlled release system capable of achieving efficient osteogenesis is in imperative demand because of limited bone substitute tissue for the treatment of bone defect. In the present study, we investigated the potential of using poly(ε-caprolactone)–hydroxyapatite (PCL–HA) composite microspheres as an injectable bone repair vehicle by controlled release of alendronate (AL), a medicine that belongs to the bisphosphonates family. The PCL/HA–AL microspheres were prepared with solid/oil/water emulsion technique, which included two processes: (1) AL was loaded on the hydroxyapatite nanoparticles; (2) the HA–AL complex was built in the PCL matrix. The spherical PCL/HA–AL microspheres were characterized with its significantly improved encapsulation efficiency of hydrophilic AL and better sustained release. Human bone mesenchymal stem cells (hMSCs) were cultured on the surface of these microspheres and exhibited high proliferative profile. Specifically, in osteogenic medium, hMSCs on the surface of PCL/HA–AL microspheres displayed superior osteogenic differentiation which was verified by alkaline phosphatase activity assay. In conclusion, by presenting strong osteogenic commitment of hMSCs in vitro, the PCL/HA–AL microspheres have the potential to be used as an injectable vehicle for local therapy of bone defect.     

Evidence for Oxidative Pathways in the Pathogenesis of PD: Are Antioxidants Candidate Drugs to Ameliorate Disease Progression?

Parkinson’s disease (PD) is a progressive neurodegenerative disorder that arises due to a complex and variable interplay between elements including age, genetic, and environmental risk factors that manifest as the loss of dopaminergic neurons. Contemporary treatments for PD do not prevent or reverse the extent of neurodegeneration that is characteristic of this disorder and accordingly, there is a strong need to develop new approaches which address the underlying disease process and provide benefit to patients with this debilitating disorder. Mitochondrial dysfunction, oxidative damage, and inflammation have been implicated as pathophysiological mechanisms underlying the selective loss of dopaminergic neurons seen in PD. However, results of studies aiming to inhibit these pathways have shown variable success, and outcomes from large-scale clinical trials are not available or report varying success for the interventions studied. Overall, the available data suggest that further development and testing of novel therapies are required to identify new potential therapies for combating PD. Herein, this review reports on the most recent development of antioxidant and anti-inflammatory approaches that have shown positive benefit in cell and animal models of disease with a focus on supplementation with natural product therapies and selected synthetic drugs.     

氢氧发动机多余物防控设计

由于多余物的危害及航天产品高精尖的发展需要,多余物防控设计已成为产品设计不可或缺的设计准则.通过对氢氧发动机多余物的特点进行分析,发动机明确了介质精度控制要求并进行了过滤器的设计,可有效对多余物进行防控.针对氢氧发动机的低温特点,还进行了发动机"潮气及未置换干净的空气"的防控设计以防"冰堵".     

Pathological lung segmentation based on random forest combined with deep model and multi-scale superpixels

Accurate segmentation of lungs in pathological thoracic computed tomography (CT) scans plays an important role in pulmonary disease diagnosis. However, it is still a challenging task due to the variability of pathological lung appearances and shapes. In this paper, we proposed a novel segmentation algorithm based on random forest (RF), deep convolutional network, and multi-scale superpixels for segmenting pathological lungs from thoracic CT images accurately. A pathological thoracic CT image is first segmented based on multi-scale superpixels, and deep features, texture, and intensity features extracted from superpixels are taken as inputs of a group of RF classifiers. With the fusion of classification results of RFs by a fractional-order gray correlation approach, we capture an initial segmentation of pathological lungs. We finally utilize a divide-and-conquer strategy to deal with segmentation refinement combining contour correction of left lungs and region repairing of right lungs. Our algorithm is tested on a group of thoracic CT images affected with interstitial lung diseases. Experiments show that our algorithm can achieve a high segmentation accuracy with an average DSC of 96.45% and PPV of 95.07%. Compared with several existing lung segmentation methods, our algorithm exhibits a robust performance on pathological lung segmentation. Our algorithm can be employed reliably for lung field segmentation of pathologic thoracic CT images with a high accuracy, which is helpful to assist radiologists to detect the presence of pulmonary diseases and quantify its shape and size in regular clinical practices.

     

全光通信网安全问题初探

本文介绍了全光通信网(AON)的概念。研究了全光网络中光层可能遭到的两种网络攻击:服务玻坏和网络窃听以及对网络通信安全的影响。提出了全光网络安全的考虑方法和可以采取的安全策略。     

Integrated Analysis of Microarray,Small RNA,and Degradome Datasets Uncovers the Role of MicroRNAs in Temperature-Sensitive Genic Male Sterility in Wheat

Temperature-sensitive genic male sterile (TGMS) line Beijing Sterility 366 (BS366) has been utilized in hybrid breeding for a long time, but the molecular mechanism underlying male sterility remains unclear. Expression arrays, small RNA, and degradome sequencing were used in this study to explore the potential role of miRNA in the cold-induced male sterility of BS366. Microspore observation showed defective cell plates in dyads and tetrads and shrunken microspores at the vacuolated stage. Differential regulation of Golgi vesicle transport, phragmoplast formation, sporopollenin biosynthesis, pollen exine formation, and lipid metabolism were observed between cold and control conditions. Pollen development was significantly represented in the 352 antagonistic miRNA-target pairs in the integrated analysis of miRNA and mRNA profiles. The specific cleavage of ARF17 and TIR1 by miR160 and miR393 were found in the cold-treated BS366 degradome, respectively. Thus, the cold-mediated miRNAs impaired cell plate formation through repression of Golgi vesicle transport and phragmoplast formation. The repressed expression of ARF17 and TIR1 impaired pollen exine formation. The results of this study will contribute to our understanding of the roles of miRNAs in male sterility in wheat.     

记忆存储式汽车后视镜疲劳测试系统的设计

介绍了一种基于单片机的记忆存储式汽车后视镜疲劳测试系统的设计。利用C8051F340单片机作为数据采集和控制电路的主要部件,控制继电器驱动后视镜电机运动。采用异步串行通讯方式与上位机实现数据传输和控制,实现PC机与多台单片机通讯。介绍了测试系统的硬件设计并给出了单片机和上位机的软件设计。实验测试表明,该测试系统能满足长时间的疲劳测试工作,其稳定性、可靠性和测试效果能够满足后视镜质量检测对系统的要求。该测试系统已在汽车后视镜质量检测中心应用,运行良好,性能稳定可靠。     

等离子体刻蚀凹栅槽影响AlGaN/GaN HEMT栅电流的机理

对等离子体干法刻蚀形成的凹栅槽结构AlGaN/GaN HEMTs肖特基电流增加的机理进行了研究.实验表明,凹栅槽结构AIGaN/GaN HEMTs肖特基栅电流增加一个数量级以上,击穿电压有一定程度的下降.利用AFM和XPS的方法分析AlGaN表面,等离子体干法刻蚀增加了AlGaN表面粗糙度,甚至出现部分尖峰状突起,增大了栅金属与AlGaN的接触面积;另一方面,等离子体轰击使AlGaN表面出现一定量的N空位,相当于栅金属与AlGaN接触界面处出现n型掺杂层,使肖特基结的隧道效应加强,降低了肖特基势垒.由此表明,AlGaN表面粗糙度的增加以及一定量的N空位出现是引起栅电流急剧增大的根本原因.     

一种新型载光敏剂的微泡制备及其基本物理特性研究

目的:制备一种包封率及载药量较高的载光敏剂微泡,并测定其物理参数。方法:制备加入大豆油载竹红菌素微泡,观察载微泡的形态、结构、观察苏丹黑对微泡的染色,以及超声辐照后苏丹黑的释放情况,测定微泡的包封率、载药量、粒径、电位分布,体外显影效果,兔肝内显影效果。结果:载竹红菌素微泡的浓度为1.4×109/ml至4.5×109/ml,粒径范围为90%以上在1μm至5μm,平均粒径为1.95μm。大豆油微泡竹红菌素的包封率大于95%,载药量为2.38±0.023 mg/ml;Zeta电位为20.3±1.6 mV;苏丹黑染色后光镜下可见大豆油及微泡壁被染成黑色,超声辐照后微泡稀释液变黑加深。结论:采用机械振荡法制备的加入大豆油载竹红菌素微泡,包封率较高,稳定性好,粒径分布好,体内外显像效果尚可,超声辐照能促使微泡中的药物释放,大豆油载药微泡作为一种光敏剂的运载体,有望实现实时监控下的体内定点靶向给药。