Biomedical Engineering: Applications, Basis and Communications

Anterior knee pain (AKP) is a common pathological condition. The most obvious problem causing knee pain is the abnormal patellar tracking mechanism. For computerized knee joint analysis, how to successfully segment the knee bones is an import issue. This paper presents a simple while effective algorithm for fully automatic femur and patella segmentation for magnetic resonance (MR) knee images through integrating edge detection and thresholding approaches. Based on consideration of computational complexity and accuracy, we develop a compound approach to segment the MR knee images. The moment preserving thresholding is first utilized to gather the bone-outline information employed to estimate the region of interest (ROI). An ROI based wavelet enhancement is proposed to restrict the contrast improvement only around the bone edges. The restriction makes both the adhesion separation of bone and surrounding tissues and the bone contour conservation become possible and avoid harsh thresholding resulting from the global based wavelet enhancement. Cooperating with the morphology operation, stable initial guess of the bone regions can be achieved. To overwhelm the main drawback of the existing edge based segmentation methods, i.e. the necessity of complicated post-processing, a new approach - FLoG is proposed to provide a feasible solution. It converts the edge detection results using LoG into a region-based format through the flow fill operation. The developed onion-growing algorithm can properly combine the initial guess of bone regions with the FLoG outputs in an efficient way. The experimental study shows our method is superior to the conventional ones in meeting the requirement of physicians. This is because our method can perform well in dealing with the tougher conditions, i.e. the partial volume and the soft tissue adhesion conditions. Because of the integration of the thresholding approach with the FLoG edge detector, our algorithm is even robust to unsatisfactory imaging conditions. Hence, our method lends itself to assisting the clinical diagnosis of knee functions.

Fibrin sealant and platelet gels are human blood-derived, biodegradable, non toxic, surgical products obtained by mixing a fibrinogen concentrate or a platelet rich plasma with thrombin, respectively. Fibrin sealant is now a well known surgical tool increasingly used to stop or control bleeding, or to provide air and fluid tightness in many surgical situations. Platelet gels are newly developed preparations that are of specific interest because they contain numerous physiological growth factors and cytikines that are released upon the activation of blood platelets by thrombin. These growth factors, including PDGF, TGF- β1, BMP, and VEGF have been shown to stimulate cell growth and differentiation with special clinical benefits for soft and bony tissue healing and regeneration. Platelet gels allow surgeons to manipulate the cellular environment of surgical sites and to guide tissue regeneration. A specific interest of such products is observed for the induction of osteogenesis and chondrogenesis. Advances in the preparation, clinical use, and safety of these two important classes of blood-derived biomaterials are reviewed.

Functional electrical stimulation (FES) is a method for restoring the functional movements of paraplegic or patients with spinal cord injuries. However, the selection of parameters that control the restoration of standing up and sitting functions has not been extensively investigated.

This work provides a method for choosing the four main items involved in evaluating the strategies for sit-stand-sit movements with the aid of a modified walker. The control method uses the arm-supported force and the angles of the legs as feedback signals to change the intensity of the electrical stimulation of the leg muscles. The control parameters, Ki and Kp, are vary for different control strategies. Four items are collected through questionnaires and used for evaluation. They are the maximum reactions of the two hands, the average reaction of the two hands, largest absolute angular velocity of the knee joints, and the sit-stand-sit duration time. The experimental data are normalized to facilitate comparison. Weighting factors are obtained and analyzed from questionnaires answered by experts and are added to evaluation process for manipulation. The results show that the best strategy is the closed-loop control with parameters Ki=0.5 and Kp=0.

In the research category of bio-informatics, gene interaction and biochemical reactions constitute a rather complicated sub-category. This area of research presents a big challenge for biologists. Determining biological pathways, and the complex chemical reactions involved, is very difficult. Nevertheless these research results are very valuable. Harnessing the calculating power of computer networks and freely circulating information, computer-drawn graphs can be used to express biological pathways, and thus provide biologists with a powerful tool to present their research. In this paper, JAVA programming language combined with extendable markup language is used to develop a bio-pathway drawing software tool that is connected to a gene database and gene expression analysis. Two currently available genetic pathway software tools, PathwayEdit and GenMAPP, were compared to the newly developed software. The participants involved in testing the software expressed a highly affirmative response to the new system.

Frozen shoulder is one of the most commonly reported shoulder disorders in adults between 40 and 60 years of age with significant pain and loss of joint range of motion (ROM), resulting in huge impact on the activities of daily living. Treatment of frozen shoulders with drugs, physical therapy and surgery that dealt with adhesive tissues may come with complications. Therefore, acupuncture therapy has become an important alternative. Puncturing needles from Tiaokou (St. 38) towards Chengshan (U.B. 57) has been used as a treatment specifically for frozen shoulders. To this day, no study on the quantitative evaluation of the efficacy of the treatment has been found in the literature. A quantitative and objective method using video-based stereophotogrammery system was developed to evaluate the treatment efficacy of acupuncture by inserting needle from St. 38 to U.B. 57. It was found that the treatment increased significantly the humeral elevation ROM from 102.91 ° ± 24.82 ° before treatment to 111.25 ° ± 22 ° after, with a mean increase of 8.34 °. This finding confirms the teachings described in the classical Chinese medical literature and will be helpful for the planning and implementation of long-term studies on the treatment mechanism and efficacy of acupuncture in frozen shoulder.

Tissue engineering is a new approach for articular cartilage repair, but the integration of engineered cartilage into the host subchondral bone is a major problem. One approach for solving this problem is to make osteochondral tissue engineering instead of cartilage tissue engineering only. The aim of the present paper was to describe two patented newly designed bioreactors for tissue-engineered osteochondral graft. The first bioreactor is double-chamber bioreactor, which is made of glass and is completely transparent. The whole system consists of one chamber for culture of chondrocytes and the other chamber for osteoblast culture. One important role for this bioreactor is to co-culture osteoblasts and chondrocytes at the same time in a biphasic scaffold. The bioreactor is modified from spinner flasks. The stirring of the magnetic bars provides medium mixing and mechanical stimulations for the cells. The second bioreactor is modified from perfusion chamber. The driven force of the medium flow is produced by siphon phenomenon. The bioreactor is composed with two parts. The first part is a modified siphon tube which can hold the biphasic scaffold for osteochondral tissue engineering. The second part is a medium reservoir bottle, which contains large amount of medium and can connect to multiple siphon tubes at the same time. The medium reservoir bottle is placed higher than the siphon tubes. The gravity will drive medium into the siphon tubes. The siphon phenomenon will make the cell-seeded scaffold covered with the medium. When the height of medium reach the height of outflow tube of the siphon tube, the medium will drain out, and the scaffold will be exposed to the air in incubator, which provides oxygen exposure. Then the gravity will make the medium refill again, the scaffold will be immersed in medium until next cycle of medium drainage out. The curve shape of the siphon tube will prevent backward bacteria contamination. The flow of the medium from reservoir through the siphon tube will produce an effect like traditional perfusion chamber bioreactor; however no power supply is necessary in this system.

The aim of this study was to evaluate the influence of implant length and bone quality on the biomechanical aspects in alveolar bone and dental implant using non-linear finite element analysis. Two fixture lengths (8 and 13mm) of Frialit-2 root-form titanium implants were buried in 4 types of bone modeled by varying the elastic modulus for cancellous bone. Contact elements were used to simulate the realistic interface fixation within the implant system. Axial and lateral (buccolingual) loadings were applied at the top of the abutment to simulate the occlusal forces. The simulated results indicated that the maximum strain values of cortical and cancellous bone increased with lower bone density. In addition, the variations of cortical bony strains between 13mm and 8mm long implants were not significantly as a results of the same contact areas between implant fixture and cortical bone were found for different implant lengths. Lateral occlusal forces significantly increased the bone strain values when compared with axial occlusal forces regardless of the implant lengths and bone qualities. Loading conditions were found as the most important factor than bone qualities and implant lengths affecting the biomechanical aspects for alveolar bone and implant systems. The simulated results implied that further understanding of the role of occlusal adjustment influencing the loading directions are needed and might affect the long-term success of an implant system.

This paper develops a forward-inverse prediction technique of an adaptive-network-based fuzzy inference system (ANFIS) to optimize the design of a relay-actuated Chinese Braille display (CBD) and to reduce the operation temperature. The key element in CBD, electromagnetic actuator assembled by relay, level, and plastic pin, must operate in lower temperature in order to have enough functional force exerted by relay to lift up Braille dots (pin-heads). However, electromagnetic actuators are often destroyed by thermal damage and the thrust force sensed from Braille dots is gradually reduced by the raising of operation temperature. Two design parameters that have the major influence on the thrust force and maximum operation temperature, including supply voltage and coil resistance of relay, were first analyzed by the thermal and electromagnetic numerical forward models to establish the basic databases for ANFIS. Using these databases, the optimal design of CBD can be forward-inversely predicted by ANFIS. As a verification of this forward-inverse mode, the forward predicted maximum operation temperature and the design thrust force inversely predicting the optimal supply voltage by ANFIS were compared with experimental data. The comparison indicates that the maximum operation temperature and the thrust force of both natural and force convection models achieved satisfactory accuracy. When two bell-shape membership functions were adopted, the best accuracy of the forward predicted maximum temperature of ANFIS reached is as high as 99.71% for natural convection model, and the best accuracy of the design thrust force for the inversely predicted supply voltage of ANFIS reached is also as high as 95.50% for force convection model. This investigation proves that the forward-inverse prediction mode developed for ANFIS with thermal and electromagnetic analyses can supply a useful soft computing technique for the optimal design of CBD.