Biomedical Engineering: Applications, Basis and Communications

The need to develop objective functional muscle torque capability models has been a major concern for exercise scientists, rehabilitation therapists, as well as biomechanists and ergonomists, for many decades. This study provides a surface response normative database of 3-D dynamic torque capability profiles for the lower extremity knee and hip joints for twenty normal males and females. The results of the regression analyses were presented for each subject per direction of exertion for each joint depicting a wide range of adjusted R² values for each of the two joints (knee flexion: .26-.91, knee extension: .23-.80; hip flexion: .33-81, hip extension: .31-.80). Furthermore, the results showed that joint torque capability was significantly influenced by dynamic parameters such as the angular velocity, and that the interaction between angular position and velocity was highly significant. Such 3-D representation may be used as a "performance capacity envelope" to comprehensively characterize an individual's dynamic joint torque capability. Potential applications cover a broad spectrum ranging from rehabilitation to ergonomic and biomechanical applications and have significant implications in terms of guiding job assignment, return to work, as well as prognosis during the rehabilitation processes.

Hydroxyapatite containing yttria-tetragonal zirconia polycrystals (Y-TZP) with different concentrations were prepared by using the conventional ball-milling technique. Samples prepared from these powders were compacted and sintered at three different temperatures (1250°C, 1400°C and 1600°C). The sintering behaviour of the composites were studied in terms of phase stability, densification and microstructural evolution. By X-ray diffraction, tetragonal zirconia as well as HA was identified as the major phases in the composites. In addition, small diffraction peaks corresponding to α-TCP was evident indicating sign of HA decomposition. Reaction between the zirconia and HA to form CaZrO₂ was also detected in the composite system containing up to 20 wt% Y-TZP. SEM examination of the sintered composites at room temperature suggested the involvement of a reactive liquid phase during sintering. The presence of zirconia phase in hydroxyapatite matrix played an important role in the stability of the HA phase.

Tendons are frequently injured by direct trauma. Tendon adhesions are a common factor compromising the results of tendon repair and to this day represent one of the most challenging problems in hand surgery. Use of controlled motion splints during the early stages of tendon recovery increases tendon gliding. Thus, a variety of controlled motion splints have been developed. This paper introduces a new controlled motion splint called the Synergistic Wrist Motion Splint (SWIMS). The "seqential quadratic programming method" was used to optimize Yang's synertistic model of the wrist/hand system, with the results being embodied in a practical controlled motion splint. Derivation of the model is discussed in detail. The dimensions of a patient's hand are input into a general formula to generate a specific SWIMS configuration for the patient. Five prototype SWIMS splints were produced and tested on 5 normal subjects. A three-dimensional motion analysis system was employed to measure the relative motion between the wrist and finger joints due to passive muscle tension for the prototype SWIMS splints, and the results are compared with the mathematical simulation or model.

The objective of this study was to provide a normative database of dynamic upper-extremity (shoulder and elbow) joint strengths to fill the current void in literature for multidimensional strength capacity profiles. The isokinetic strength of the elbow and shoulder joints was tested for twenty normal males and females. The independent variables consisted of joint angular position, joint angular velocity, direction of exertion, and gender. The measured joint strength (torque, Nm) was the only defined dependent variable. The majority of existing joint strength prediction models and normative databases are static (isometric) in nature. The few available dynamic models are reported in the form of torque as a function of joint angle. Since joint strength is a function of both the joint angular position and angular velocity, descriptive models should take this interaction into consideration. The dynamic joint strengths of the subjects were studied using the KIN_COM 125E Plus. A second-order multiple regression analysis was used to model the dynamic 3-D strength surface response of each joint in each direction of exertion. Analysis of variance (ANOVA) with repeated measures design was used to test for the effects of gender, angular position, angular velocity, and direction on the dynamic strength of each joint, joint strength was significantly influenced by dynamic parameters such as the angular velocity. The interaction between angular position and velocity was highly significant. 3-D strength surface representation may be used as a "performance capacity envelope" to comprehensively characterize an individual's dynamic joint strength performance.

The prevalence of ovarian tumor malignancy can be monitored by the degree of irregularity in the ovarian contour and by the septal structure inside the tumor observed in ultrasonic images. However the 2D ultrasonic images can not integrate 3D information form the ovarian tumor. In this paper, we present an algorithm that can render the 3D image of an ovarian tumor by reconstructing the 2D ultrasonic images into a 3D data set. This is based on sequentially boundary detection in a series of 2D images to form a 3D tumor contour. This contour is then used as a barrier to remove the data containing the other tissue adhering to the tumor surface. The final 3D image rendered by the isolated data provides a clear view of both the surface and inner structure of the ovarian tumor.

This study scientifically measures the dynamic gait characteristics and energy cost of six male below-knee amputees, three vascular and three traumatic, while wearing SACH, single axis and multiple axis prosthetic feet via six-camera motion analysis, metabolic measurement cart and heavy-duty treadmill. Subjective results are additionally determined via questionnaire after testing. Motion analysis showed statistically significant differences at p < 0.05 between the solid ankle cushion heel (SACH), single axis and multiple axis foot in the velocity, cadence, stride length end gait cycle. Significant differences were found in energy cost among the prosthetic feet tested, and significant changes in walking under different speeds and different inclines. Results provide quantitative and qualitative information about the dynamic performance of the various feet which can be helpful in prescribing the optimal prosthetic foot for individual amputees.