Burgessslattery3082

The device employs locking forceps and a tilting sensor to rule out effects of the gripping force and to compensate for changes in the force due to tilting, which improves the measurement accuracy. GDC-0980 concentration The performance of the device was investigated in 60 eyes of 30 consecutive anaesthetized patients immediately prior to ophthalmic surgery. The results showed that the measured EOM tension in each rectus muscles agreed with previous findings 48.3 ± 14.5 g (0.82 ± 0.28 g/deg, mean ± SD) for the lateral rectus, 45.6 ± 13.2 g (0.82 ± 0.23 g/deg) for the medial rectus, 48.6 ± 14.7 g (0.71 ± 0.21 g/deg) for the inferior rectus and 53.4 ± 13.7 g (0.77 ± 0.25 g/deg) for the superior rectus.Currently, abdominal finite element models overlook the organs such as gallbladder, bladder, and intestines, which instead are modeled as a simple bag that is not included in the analysis. Further characterization of the material properties is required for researchers to include these organs into models. This study characterized the mechanical properties of human and porcine gallbladder, bladder, and intestines using uniaxial tension loading from the rates of 25%/s to 500%/s. Small differences were observed between human and porcine gallbladder elastic modulus, failure stress, and failure strain. Strain rate was determined to be a significant factor for predicting porcine gallbladder elastic modulus and failure stress which were found to be 9.03 MPa and 1.83 MPa at 500%/s. Human bladder was observed to be slightly stiffer with a slightly lower failure stress than porcine specimens. Both hosts, however, demonstrated a strain rate dependency with the elastic modulus and failure stress increasing as the rate increased with the highest elastic modulus (2.16 MPa) and failure stress (0.65 MPa) occurring at 500%/s. Both human and porcine intestines were observed to be affected by the strain rate. Failure stress was found to be 1.6 MPa and 1.42 MPa at 500%/s for the human and porcine intestines respectively. For all properties found to be strain rate dependent, a numerical model was created to quantify the impact. These results will enable researchers to create more detailed finite element models that include the gallbladder, bladder, and intestines.Several sports-related injuries and orthopedic treatments need the necessity of corrective shoes that can assuage the excessive pressure on sensitive locations of the foot. In the present work, we study the mechanical and energy absorption characteristics of density-graded foams designed for shoe midsoles. The stress-strain responses of polyurea foams with relative densities (nominal density of foam divided by the density of water) of 0.095, 0.23, and 0.35 are obtained experimentally and used as input to a semi-analytical model. Using this model, three-layered foam laminates with various gradients are designed and characterized in terms of their weight, strength, and energy absorption properties. We show that, in comparison with monolithic foams, significant improvement in strength and energy absorption performance can be achieved through density gradation. Our findings also suggest that there is not a single gradient that offers a superior combination of strength, energy absorption, and weight. Rather, an optimal gradient depends on the plantar location and pressure. Depending on the magnitude of the local plantar pressure, density gradients that lead to the highest specific energy absorption are identified for normal walking and running conditions.The viscoelastic behavior of vitreous gel is due to the presence of biopolymers in its structure. Fluid properties of the vitreous is mainly the result of interactions between the characteristics of collagen type II and Hyaluronic Acid networks. Having a better understanding of the structure of each component and their changes during aging and various diseases such as diabetes can lead to better monitoring and treatment options. We study the effects of collagenase type II on 44 samples of porcine vitreous using an in situ rheological experiment in comparison with 18 eyes in a control group injected with Phosphate Buffered Saline Solution. We analyze the behavior of each component over time in both groups. We focus on the changes of viscosity and elasticity of the collagen network within the vitreous. The results of the analysis in this study show that the changes in the fluid properties of the vitreous after collagenase injection is driven by the structural alterations of the collagen network. Creep compliance values of the collagen network are significantly higher in the first group compared to the control group one hour and twenty-four hours after the injection. In contrast, creep compliance of the HA network shows no statistically significant change one hour after the injection in both groups. The results of the reported analysis of individual components in this study support the previous findings on the alterations within the vitreous structure in its entirety.A mechanobiological model of bone growth aimed for the design of medical devices for the treatment of limb deformities during childhood and adolescence was developed. Dimensional analysis was introduced as a tool for the systematic evaluation of the influence attributed to different factors that might modify the bone growth process. Simplifications were proposed, allowing the reduction of bone growth relevant parameters to four non-dimensional numbers, representing the chondrocyte sensitivity to stress, the epiphyseal plate geometry, the bone rigidity and the time. Benchmark situations considered for model validation were bone growth under normal conditions and an epiphyseal stapling treatment. A finite elements approach was used to analyze bone growth in the distal portion of the femur. Results are shown to be consistent with corresponding clinical data published in the literature, which indicates the potential of the here proposed method for the design of specific devices and treatments.The human ureters have not been thoroughly explored from the biomechanics perspective, despite the wealth of such data for other soft-tissue types. This study was motivated by the need to use relevant biomechanical data from human ureters and microstructure-based material formulations for simulations of ureteral peristalsis and stenting. Our starting choice was the four-fiber family model that has proven its validity as a descriptor of the multiaxial response of cardiovascular tissues. The degree of model complexity, required for rigorous fits to passive quasi-static pressure-diameter-force data at several axial stretches, was systematically investigated. Ureteral segments from sixteen human autopsy subjects were evaluated. A diagonal and axial family model allowed equally-good fits as the full model for all age groups and ureteral regions; considerably better than those allowed by the phenomenological Fung-type model whose root-mean-square error of fitting was three-fold greater. This reduced model mimicked the structure seen in histologic sections, namely plentiful diagonal collagen fibers in the lamina propria and axial fibers in the muscle and adventitia.