Narrow Results

The subcellular location of β-catenin and N-cadherin in cultured bovine endothelial cells (ECs) exposed to hydrostatic pressure was investigated. ECs were exposed to physiological blood pressure under a hydrostatic head of culture medium for 24 hours. Pressured ECs exhibited changes in morphology and proliferation. Immunofluorescent localization of β-catenin and N-cadherin indicated changes in their distribution in pressured compared to control cells, β-catenin was located at the cell membrane in control cells but in the cytoplasm and nucleus of pressured cells. In contrast, N-cadherin was associated with the cell membrane in pressure cells. Changes in the location of these two proteins in ECs have previously been associated with increase proliferation and changes in cell morphology. Therefore the hydrostatic pressure induced changes in these may be mediated, in part, by β-catenin and N-cadherin.

The purpose of this study was to reveal circumferential strain distributions in aortas by using a newly designed observation technique. Six cylindrical descending thoracic aortas were excised from Japanese white rabbits and stretched in the longitudinal direction to their in vivo length. Five-millimeter long needles (φ 0.4 mm) were penetrated into the aorta as a marker of circumferential displacement of the aorta. During application of internal pressure ranging from 0 to 200 mmHg, displacements of needles were recorded with a CCD camera from longitudinal direction of the aorta and with other two CCD cameras from both lateral sides of aorta. The images of cameras were used to determine the penetration points of all needles. From the penetration points, we calculated the local circumferential lengths of aorta and circumferential local stretch ratios. As a result, circumferential stretch ratio of ventral side of aorta was significantly higher than that of dorsal side (p < 0.05). This result suggests that nonuniform strain distributions exist in the circumferential direction of aortas. The present method was useful to measure the detailed mechanical property of blood vessels and to understand vascular mechanics.

We construct numerical aneurysm models arisen from both straight and curved arteries, under the hypothesis that high local wall shear stress larger than a certain threshold value will lead to a linear decrease in the wall mechanical properties. Development of aneurysm is observed in both the straight and curved models. In the straight model, the growth of aneurysm is small and only at the distal neck region, and the aneurysm stops growing after several steps. In contrast, in the curved model, the aneurysm continues to grow in height and width. Our computer simulation study shows that even if the wall shear stress inside an aneurysm is low, aneurysm development can occur due to degeneration of the wall distal and proximal to the aneurysm. The interaction between the hemodynamic change (caused by the shape change) and the wall degeneration is key to the development of aneurysms. Our method demonstrates the potential utility of rule-based numerical methods in the investigation of developmental biology of cardiovascular diseases.

Truly sustainable development can be conceptualized as the sustained attempt to let something or somebody unfold its potential according to its own unique nature. Against the unsustainable paradigms of mass production and overconsumption in today’s world, this chapter presents a series of lesser-known counternarratives of sustainable development which disconnect the world of business from the anxiety of busyness and reconnects it to a broader context of being grounded and connected to the Earth, mindful of the biomechanics of our own bodies and embodying a sensitive mindset of sustainable development. This approach is aligned with the first principle of true storytelling which urges us to be true to ourselves in the sense of caring for and developing a sustainable future, not only for ourselves, but for all living beings.

Modern gait analysis results in large quantities of correlated data. A current challenge in the field is the development of appropriate data analysis techniques for the representation and interpretation of these data. Knee osteoarthritis is a common debilitating disease of the musculoskeletal system that has been the focus of many gait studies in recent years. Various data analysis techniques have been used to extract pathological information from gait data in these studies. The following review discusses the successes and limitations of many of these analysis techniques in the attempt to understand the biomechanics of knee osteoarthritis.

This chapter focuses on biomechanics of the foot in both the normal and the diabetic foot. The biomechanics of the foot in the normal gait cycle is discussed. Plantar pressure measurements in the foot including both platform and in-sole types of measurements to identify local areas of pressure in the foot are also described. Pathological changes in the diabetic foot lead to altered biomechanics in the foot different from that of the normal foot.

This study was attempted to develop a new cell finite element model to present the cell mechanical response underlying the compression. The geometry and material properties of cytomembrane, cytoplasm, cytoskeleton, and the nucleus were obtained according the previous experimental data. 5Mpa compression loading was simulated in LS-DYNA solvers, the displacement, strain, stress contour of the cytomembrane, cytoplasm, cytoskeleton, and the nucleus were calculated in this study. According the prediction of this FE modeling, the mechanotransduction sequence of each part in cell was observed from cytomembrane to cytoskeleton and then the cytoplasm, finally to the nucleus. This phenomenon might indicate that the remodeling behavior of the cell cytoskeleton was influenced by the nucleus mechanical response.

Trilateral research methods are developed by the author integrating morphology, molecular biology (physiology and biochemistry), and molecular genetics of remodeling by means of biomechanics. Through this research method the author develops artificial bone marrow chamber using bioceramics.

The author discovers through studies on evolution of hemopoiesis that the morphology of an organism can be changed by vicissitudes of inner or outer stimuli of biomechanics, i.e., environmental factors, which act to the organism, and if these vicissitudes of biomechanical stimuli are transmitted to the next generation morphological changes can be transmitted. Through this discovery the use and disuse theory of Lamarck can be explained biomechanically in molecular genetics.

Experimental evolutionary studies are carried out as follows: developing artificial bone marrow biochambers, the author has implanted them into archetype vertebrates as well as mammals, compared them each other, and analyzed them. Developments of hemopoiesis in bone marrow chambers in phylogeny are evident as the action of the gravity in terrestrialization, which is converted into heightening of blood pressure in chondrichthyes. As conclusion use and disuse theory is evidenced in second revolution of vertebrates for the gravity to trigger genetic expression in mesenchymal cells not only producing hemopoiesis conjugated with ossification of the cartilage but inducing major histocompatibility complex (MHC).

We have developed a new artificial intervertebral disc prosthesis consisting of a triaxial three-dimensional fabric (3-DF) woven by an ultra-high molecular weight polyethylene fiber and spray-coated bioactive ceramics on the disc surface. The arrangement of weave properties led to the mechanical behavior of 3-DF disc similar to the natural intervertebral disc. Using a sheep model, total intervertebral replacement using 3-DF disc either coated by hydroxyapatite or apatite-wollastonite glass ceramics was conducted with or without initial fixation. Without the use of initial fixation, interface bony union was detected, however, the segmental motion decreased at six months postoperatively. The use of temporary fixation provided a nearly physiological mobility as well as the increased fusion rate at six months. A scanning electron microscopy showed that each fiber of 3-DF disc had a direct contact to trabecula. This study first highlighted the in vivo effectiveness of artificial intervertebral disc experimentally, and clarified further problems in clinical application.

In this research, we propose an "Athlete Robot" which is compatible with a biomechanical structure of a human. In our work, pneumatic muscle is used for the actuator. We also provide a method to describe the properties of musculoskeletal leg with "Convex Polygon of Forces". In the experiment, we observed sway of the center of gravity similar to a human during bipedal stance. Our results show that the robot which has well-designed leg can land softly from one meter drop by exploiting the anti-gravity muscles and its compliance. In addition, by using preset stiffness of the musculoskeletal leg, we can control the direction of the bouncing predictively. The musculoskeletal robot helps to illuminate design principles of the robot which can move quickly and skillfully in the real world.

This paper presents the construction of individual dynamic models of human lower limbs using kinematics from Clinical Gait Analysis(CGA) data and Body Segment Inertia Parameters(BSIP) from predictive equations. It’s used human lower limbs BSIP from predictive equations and human kinematics from CGA data, to get individual BSIP and kinematic data. The the human dynamic model is built in a dynamic simulation software environment, to create human body dynamic models, and the CGA kinematic data is used as input to study model dynamics and control strategies. This approach would allow the testing and simulation of complex dynamic models without going through the tedious and error prone process of manually calculating equations of motion.

It’s shown the use of the strategy presented to collect the data to be used in the simulation of a teen age boy or girl to be used latter in the simulation of a lower limb exoskeleton.