The Experts below are selected from a list of 1884 Experts worldwide ranked by ideXlab platform
Ramona Okumura - One of the best experts on this subject based on the ideXlab platform.
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effects of alignment changes on stance phase pressures and Shear Stresses on transtibial amputees measurements from 13 transducer sites
International Conference of the IEEE Engineering in Medicine and Biology Society, 1998Co-Authors: Joan E Sanders, D M Bell, Ramona Okumura, A J DralleAbstract:Interface pressures and Shear Stresses were measured at 13 sites on two unilateral below-knee amputee subjects ambulating with lower-limb patellar-tendon-bearing prostheses. Interface Stresses at the time of the first peak in the shank axial force-time curve were investigated at different socket-shank alignment settings. Stress magnitudes ranged from 1.2 to 214.7 kPa for pressure and 0.4 to 79.6 kPa for Resultant Shear Stress, and changes in Stress due to misalignment ranged from 1.3 to 80.7 kPa for pressure and from 0.2 to 38.0 kPa for Resultant Shear Stress. For both subjects interface Stress changes were much greater in the anterior socket region than in the lateral or posterior regions. Thus, alignment changes had a localized effect on interface Stresses. Plots of alignment versus pressure or Resultant Shear Stress were nonlinear for both subjects, in a number of cases maximizing or minimizing at the nominal alignment, indicating complex interface Stress-alignment relationships. Variation (standard deviation/mean) was not significantly different for nominal versus misaligned steps, indicating that the subjects adapted well to the alignment changes. Session to session differences in interface Stresses were typically larger than interface Stress differences induced by alignment modifications. Thus, while these subjects compensated well for alignment changes to maintain consistent interface Stresses within a session, they did not do so for different sessions conducted weeks apart.
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interface pressures and Shear Stresses at thirteen socket sites on two persons with transtibial amputation
Journal of Rehabilitation Research and Development, 1997Co-Authors: Joan E Sanders, A J Dralle, Dickson Lam, Ramona OkumuraAbstract:Residual limb/prosthetic socket interface pressures and Shear Stresses were measured at 13 sites on two subjects with unilateral transtibial amputation (TTA) using total-contact patellar-tendon-bearing prostheses. Maximal interface Stresses during stance phase for each of 13 transducer sites were determined, then means for all steps calculated. Maximal pressure and Resultant Shear Stress during stance phase were shown at anterior distal or mid-limb sites and the maxima occurred during the first 50% of stance phase. Anterior medial and lateral proximal sites showed their greatest pressure during the second 50%. At lateral mid-limb and popliteal fossa sites, Resultant Shear Stress directions suggest that soft tissue was displaced toward the socket brim during weight-bearing. Results also suggest that skin across the distal tibial crest was in tension at the times of the first and second peaks in the shank axial force-time curve in all sessions. Significant difference (p 3 weeks apart were apparent for both subjects.
Navaneetha Santhanam - One of the best experts on this subject based on the ideXlab platform.
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Multi-Organ toxicity demonstration in a functional human in vitro system composed of four organs
Scientific Reports, 2016Co-Authors: Carlota Oleaga, Catia Bernabini, Alec S.t. Smith, Balaji Srinivasan, Max Jackson, William Mclamb, Vivien Platt, Richard Bridges, Yunqing Cai, Navaneetha SanthanamAbstract:We report on a functional human model to evaluate multi-organ toxicity in a 4-organ system under continuous flow conditions in a serum-free defined medium utilizing a pumpless platform for 14 days. Computer simulations of the platform established flow rates and Resultant Shear Stress within accepted ranges. Viability of the system was demonstrated for 14 days as well as functional activity of cardiac, muscle, neuronal and liver modules. The pharmacological relevance of the integrated modules were evaluated for their response at 7 days to 5 drugs with known side effects after a 48 hour drug treatment regime. The results of all drug treatments were in general agreement with published toxicity results from human and animal data. The presented phenotypic culture model exhibits a multi-organ toxicity response, representing the next generation of in vitro systems and constitutes a step towards an in vitro “human-on-a-chip” assay for systemic toxicity screening.
Joan E Sanders - One of the best experts on this subject based on the ideXlab platform.
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effects of alignment changes on stance phase pressures and Shear Stresses on transtibial amputees measurements from 13 transducer sites
International Conference of the IEEE Engineering in Medicine and Biology Society, 1998Co-Authors: Joan E Sanders, D M Bell, Ramona Okumura, A J DralleAbstract:Interface pressures and Shear Stresses were measured at 13 sites on two unilateral below-knee amputee subjects ambulating with lower-limb patellar-tendon-bearing prostheses. Interface Stresses at the time of the first peak in the shank axial force-time curve were investigated at different socket-shank alignment settings. Stress magnitudes ranged from 1.2 to 214.7 kPa for pressure and 0.4 to 79.6 kPa for Resultant Shear Stress, and changes in Stress due to misalignment ranged from 1.3 to 80.7 kPa for pressure and from 0.2 to 38.0 kPa for Resultant Shear Stress. For both subjects interface Stress changes were much greater in the anterior socket region than in the lateral or posterior regions. Thus, alignment changes had a localized effect on interface Stresses. Plots of alignment versus pressure or Resultant Shear Stress were nonlinear for both subjects, in a number of cases maximizing or minimizing at the nominal alignment, indicating complex interface Stress-alignment relationships. Variation (standard deviation/mean) was not significantly different for nominal versus misaligned steps, indicating that the subjects adapted well to the alignment changes. Session to session differences in interface Stresses were typically larger than interface Stress differences induced by alignment modifications. Thus, while these subjects compensated well for alignment changes to maintain consistent interface Stresses within a session, they did not do so for different sessions conducted weeks apart.
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interface pressures and Shear Stresses at thirteen socket sites on two persons with transtibial amputation
Journal of Rehabilitation Research and Development, 1997Co-Authors: Joan E Sanders, A J Dralle, Dickson Lam, Ramona OkumuraAbstract:Residual limb/prosthetic socket interface pressures and Shear Stresses were measured at 13 sites on two subjects with unilateral transtibial amputation (TTA) using total-contact patellar-tendon-bearing prostheses. Maximal interface Stresses during stance phase for each of 13 transducer sites were determined, then means for all steps calculated. Maximal pressure and Resultant Shear Stress during stance phase were shown at anterior distal or mid-limb sites and the maxima occurred during the first 50% of stance phase. Anterior medial and lateral proximal sites showed their greatest pressure during the second 50%. At lateral mid-limb and popliteal fossa sites, Resultant Shear Stress directions suggest that soft tissue was displaced toward the socket brim during weight-bearing. Results also suggest that skin across the distal tibial crest was in tension at the times of the first and second peaks in the shank axial force-time curve in all sessions. Significant difference (p 3 weeks apart were apparent for both subjects.
A J Dralle - One of the best experts on this subject based on the ideXlab platform.
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effects of alignment changes on stance phase pressures and Shear Stresses on transtibial amputees measurements from 13 transducer sites
International Conference of the IEEE Engineering in Medicine and Biology Society, 1998Co-Authors: Joan E Sanders, D M Bell, Ramona Okumura, A J DralleAbstract:Interface pressures and Shear Stresses were measured at 13 sites on two unilateral below-knee amputee subjects ambulating with lower-limb patellar-tendon-bearing prostheses. Interface Stresses at the time of the first peak in the shank axial force-time curve were investigated at different socket-shank alignment settings. Stress magnitudes ranged from 1.2 to 214.7 kPa for pressure and 0.4 to 79.6 kPa for Resultant Shear Stress, and changes in Stress due to misalignment ranged from 1.3 to 80.7 kPa for pressure and from 0.2 to 38.0 kPa for Resultant Shear Stress. For both subjects interface Stress changes were much greater in the anterior socket region than in the lateral or posterior regions. Thus, alignment changes had a localized effect on interface Stresses. Plots of alignment versus pressure or Resultant Shear Stress were nonlinear for both subjects, in a number of cases maximizing or minimizing at the nominal alignment, indicating complex interface Stress-alignment relationships. Variation (standard deviation/mean) was not significantly different for nominal versus misaligned steps, indicating that the subjects adapted well to the alignment changes. Session to session differences in interface Stresses were typically larger than interface Stress differences induced by alignment modifications. Thus, while these subjects compensated well for alignment changes to maintain consistent interface Stresses within a session, they did not do so for different sessions conducted weeks apart.
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interface pressures and Shear Stresses at thirteen socket sites on two persons with transtibial amputation
Journal of Rehabilitation Research and Development, 1997Co-Authors: Joan E Sanders, A J Dralle, Dickson Lam, Ramona OkumuraAbstract:Residual limb/prosthetic socket interface pressures and Shear Stresses were measured at 13 sites on two subjects with unilateral transtibial amputation (TTA) using total-contact patellar-tendon-bearing prostheses. Maximal interface Stresses during stance phase for each of 13 transducer sites were determined, then means for all steps calculated. Maximal pressure and Resultant Shear Stress during stance phase were shown at anterior distal or mid-limb sites and the maxima occurred during the first 50% of stance phase. Anterior medial and lateral proximal sites showed their greatest pressure during the second 50%. At lateral mid-limb and popliteal fossa sites, Resultant Shear Stress directions suggest that soft tissue was displaced toward the socket brim during weight-bearing. Results also suggest that skin across the distal tibial crest was in tension at the times of the first and second peaks in the shank axial force-time curve in all sessions. Significant difference (p 3 weeks apart were apparent for both subjects.
Carlota Oleaga - One of the best experts on this subject based on the ideXlab platform.
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Multi-Organ toxicity demonstration in a functional human in vitro system composed of four organs
Scientific Reports, 2016Co-Authors: Carlota Oleaga, Catia Bernabini, Alec S.t. Smith, Balaji Srinivasan, Max Jackson, William Mclamb, Vivien Platt, Richard Bridges, Yunqing Cai, Navaneetha SanthanamAbstract:We report on a functional human model to evaluate multi-organ toxicity in a 4-organ system under continuous flow conditions in a serum-free defined medium utilizing a pumpless platform for 14 days. Computer simulations of the platform established flow rates and Resultant Shear Stress within accepted ranges. Viability of the system was demonstrated for 14 days as well as functional activity of cardiac, muscle, neuronal and liver modules. The pharmacological relevance of the integrated modules were evaluated for their response at 7 days to 5 drugs with known side effects after a 48 hour drug treatment regime. The results of all drug treatments were in general agreement with published toxicity results from human and animal data. The presented phenotypic culture model exhibits a multi-organ toxicity response, representing the next generation of in vitro systems and constitutes a step towards an in vitro “human-on-a-chip” assay for systemic toxicity screening.