Search

Small-diameter vascular grafts (diameter

Bioprosthetic heart valves (BHVs) used in clinics are fabricated via glutaraldehyde (GLUT) crosslinking, which results in cytotoxicity and causes eventual valve calcification after implantation into the human body; therefore, the average lifetime and application of BHVs are limited. To address these issues, the most commonly used method is modification with amino acids, such as glycine (GLY), which is proven to effectively reduce toxicity and calcification. In this study, we used the l-glutathione (GSH) in a new modification treatment based on GLUT-crosslinked bovine pericardium (BP) as the GLUT + GSH group, BPs crosslinked with GLUT as GLUT-BP (control group), and GLY modification based on GLUT-BP as the GLUT + GLY group. We evaluated the characteristics of BPs in different treatment groups in terms of biomechanical properties, cell compatibility, aldehyde group content detection, and the calcification content. Aldehyde group detection tests showed that the GSH can completely neutralize the residual aldehyde group of GLUT-BP. Compared with that of GLUT-BP, the endothelial cell proliferation rate of the GLUT + GSH group increased, while its hemolysis rate and the inflammatory response after implantation into the SD rat were reduced. The results show that GSH can effectively improve the cytocompatibility of the GLUT-BP tissue. In addition, the results of the uniaxial tensile test, thermal shrinkage temperature, histological and SEM evaluation, and enzyme digestion experiments proved that GSH did not affect the ECM stability and biomechanics of the GLUT-BP. The calcification level of GLUT-BP modified using GSH technology decreased by 80%, indicating that GSH can improve the anti-calcification performance of GLUT-BP. Compared with GLUT-GLY, GLUT + GSH yielded a higher cell proliferation rate and lower inflammatory response and calcification level. GSH can be used as a new type of anti-calcification agent in GLUT crosslinking biomaterials and is expected to expand the application domain for BHVs in the future.

Video object segmentation and tracking has been widely used in many video communication applications. This paper proposes an effective method of detecting and tracking the moving maritime objects in video sequences. An approximation algorithm, which adopts visual attention architecture to reduce the wavy noises and make the object distinct from the background, segments the regions of interest quickly. Then, a modified temporal differencing method is proposed to eliminate the background and detect the moving maritime object. On the multi-object tracking process, an adaptive choosing the global nearest neighbor algorithm is presented based on a linear dynamic model. Furthermore, an effective occlusion reasoning method is proposed, which partly solves the occlusion problem. Experimental results show that the proposed real-time system performs well in various maritime video sequences.

A system for moving object detection and shadow extermination is described in this paper. In this system, an adaptive background model is built, which can achieve the process of initialization automatically. With an improved hybrid algorithm, moving objects are detected effectively, while a ghost detection model is used to detect ghost phenomena and makes the system more robust. Finally, an approach to exterminate shadow in HSIG color space is presented, yielding satisfying results.