Simulation-Based Unassisted Sit-to-Stand Motion Prediction for Healthy Young Individuals

2014 ◽  
Author(s):  
Burak Ozsoy ◽  
James Yang
Keyword(s):  
Experimental Studies ◽  
Three Dimensional ◽  
Bilateral Symmetry ◽  
Motion Prediction ◽  
Daily Lives ◽  
Joint Torques ◽  
Sit To Stand ◽  
Limb Injuries ◽  
Common Activity ◽  
Musculoskeletal Abnormalities

Sit-to-stand (STS) is a common activity in daily lives which requires relatively high joint torques and a robust coordination of lower and upper extremities with postural stability. Many elderly, people with lower limb injuries, and patients with neurological disorders or musculoskeletal abnormalities have difficulties in accomplishing this task. In contrast to the literature on numerous experimental studies of STS, there are limited studies that were carried out through simulations. In literature, mostly bilateral symmetry was assumed for STS tasks, however even for healthy people, it is more difficult to perform STS tasks with a perfect bilateral symmetry. The goal of this research is to develop a three-dimensional unassisted STS motion prediction formulation for healthy young individuals. Predicted results will be compared with experimental results found in literature for the validation of the proposed formulation.

Comparison of Cylindrical Wrapping Geometries to Via Points for Modeling Muscle Paths in the Estimation of Sit-to-Stand Muscle Forces

2013 ◽  
Author(s):  
Valerie Norman-Gerum ◽  
John McPhee
Keyword(s):  
Muscle Force ◽  
Inverse Dynamics ◽  
Three Dimensional ◽  
Standing Position ◽  
Minimum Length ◽  
Muscle Forces ◽  
Joint Torques ◽  
Sit To Stand ◽  
Cylindrical Geometries ◽  
Anatomical Constraints

To better understand the complexities of rising from a seated to a standing position, a model of the human has been created. Sit-to-stand kinematics as well as ground reaction forces were measured experimentally and are used in an inverse dynamics analysis to estimate nine muscle forces during motion. Calculated muscle forces are sensitive to assumptions made when modeling muscle paths. Changes in the line of action of a muscle due to interaction with anatomical constraints are often accounted for by including fixed via points in a model. Here an alternate approach of representing anatomical constraints using three-dimensional cylindrical geometries is derived and presented. In this mathematical model the course of the muscle is determined as the minimum-length path where the muscle is allowed to wrap freely over the surface of the cylinder. Muscle forces are estimated for sit-to-stand by resolving net joint torques using an objective function giving preference to solutions minimizing both muscle stresses and abrupt changes in muscle forces. This is the first time muscle forces have been presented for sit-to-stand using a musculoskeletal model with included anatomical constraints represented using cylindrical wrapping geometries alone. A comparison of calculated muscle force patterns using fixed via points and wrapping points versus three-dimensional wrapping surfaces is made with reference to electromyographic phase data. For the sit-to-stand motion, the inclusion of anatomical constraints as three-dimensional cylindrical geometries results in calculation of muscle forces more true to the experimental data and more consistent with the belief that gradual motions are created by gradual changes in muscle force over time.

scholarly journals Symmetry perception by poultry chicks and its implications for three-dimensional object recognition

2011 ◽  
Vol 279 (1730) ◽  
pp. 841-846 ◽  
Author(s):  
Elena Mascalzoni ◽  
Daniel Osorio ◽  
Lucia Regolin ◽  
Giorgio Vallortigara
Keyword(s):  
Object Recognition ◽  
Spherical Surface ◽  
Experimental Studies ◽  
Three Dimensional ◽  
Bilateral Symmetry ◽  
Two Dimensional ◽  
Three Dimensional Objects ◽  
Underlying Mechanisms ◽  
Dimensional Object ◽  
Symmetry Perception

Bilateral symmetry is visually salient to diverse animals including birds, but whereas experimental studies typically use bilaterally symmetrical two-dimensional patterns that are viewed approximately fronto-parallel; in nature, animals observe three-dimensional objects from all angles. Many animals and plant structures have a plane of bilateral symmetry. Here, we first (experiment I) give evidence that young poultry chicks readily generalize bilateral symmetry as a feature of two-dimensional patterns in fronto-parallel view. We then test the ability of chicks to recognize symmetry in images that would be produced by the transformed view produced by a 40° horizontal combined with a 20° vertical rotation of a pattern on a spherical surface. Experiment II gives evidence that chicks trained to distinguish symmetrical from asymmetrical patterns treat rotated views of symmetrical ‘objects’ as symmetrical. Experiment III gives evidence that chicks trained to discriminate rotated views of symmetrical ‘objects’ from asymmetrical patterns generalize to novel symmetrical objects either in fronto-parallel or rotated view. These findings emphasize the importance of bilateral symmetry for three-dimensional object recognition and raise questions about the underlying mechanisms of symmetry perception.

Muscle Forces and Their Contributions to Vertical and Horizontal Acceleration of the Center of Mass During Sit-to-Stand Transfer in Young, Healthy Adults

2016 ◽  
Vol 32 (5) ◽  
pp. 487-503 ◽  
Author(s):  
Elena J. Caruthers ◽  
Julie A. Thompson ◽  
Ajit M.W. Chaudhari ◽  
Laura C. Schmitt ◽  
Thomas M. Best ◽  
...  
Keyword(s):  
Muscle Force ◽  
Center Of Mass ◽  
Three Dimensional ◽  
Gluteus Maximus ◽  
Healthy Adults ◽  
Muscle Forces ◽  
Dynamic Simulations ◽  
Joint Torques ◽  
Main Contributor ◽  
Sit To Stand

Sit-to-stand transfer is a common task that is challenging for older adults and others with musculoskeletal impairments. Associated joint torques and muscle activations have been analyzed two-dimensionally, neglecting possible three-dimensional (3D) compensatory movements in those who struggle with sit-to-stand transfer. Furthermore, how muscles accelerate an individual up and off the chair remains unclear; such knowledge could inform rehabilitation strategies. We examined muscle forces, muscleinduced accelerations, and interlimb muscle force differences during sit-to-stand transfer in young, healthy adults. Dynamic simulations were created using a custom 3D musculoskeletal model; static optimization and induced acceleration analysis were used to determine muscle forces and their induced accelerations, respectively. The gluteus maximus generated the largest force (2009.07 ± 277.31 N) and was a main contributor to forward acceleration of the center of mass (COM) (0.62 ± 0.18 m/s2), while the quadriceps opposed it. The soleus was a main contributor to upward (2.56 ± 0.74 m/s2) and forward acceleration of the COM (0.62 ± 0.33 m/s2). Interlimb muscle force differences were observed, demonstrating lower limb symmetry cannot be assumed during this task, even in healthy adults. These findings establish a baseline from which deficits and compensatory strategies in relevant populations (eg, elderly, osteoarthritis) can be identified.

scholarly journals Targeting hepatocyte growth factor in epithelial–stromal interactions in an in vitro experimental model of human periodontitis

Odontology ◽  
2021 ◽  
Author(s):  
Yoko Yamaguchi ◽  
Akira Saito ◽  
Masafumi Horie ◽  
Akira Aoki ◽  
Patrick Micke ◽  
...  
Keyword(s):  
Growth Factor ◽  
Hepatocyte Growth Factor ◽  
Experimental Studies ◽  
Three Dimensional ◽  
Collagen Gel ◽  
Neutralizing Antibody ◽  
Chronic Inflammatory Disease ◽  
Collagen Degradation ◽  
Hepatocyte Growth

AbstractPeriodontitis is a chronic inflammatory disease leading to progressive connective tissue degradation and loss of the tooth-supporting bone. Clinical and experimental studies suggest that hepatocyte growth factor (HGF) is involved in the dysregulated fibroblast–epithelial cell interactions in periodontitis. The aim of this study was to explore effects of HGF to impact fibroblast-induced collagen degradation. A patient-derived experimental cell culture model of periodontitis was applied. Primary human epithelial cells and fibroblasts isolated from periodontitis-affected gingiva were co-cultured in a three-dimensional collagen gel. The effects of HGF neutralizing antibody on collagen gel degradation were tested and transcriptome analyses were performed. HGF neutralizing antibody attenuated collagen degradation and elicited expression changes of genes related to extracellular matrix (ECM) and cell adhesion, indicating that HGF signaling inhibition leads to extensive impact on cell–cell and cell–ECM interactions. Our study highlights a potential role of HGF in periodontitis. Antagonizing HGF signaling by a neutralizing antibody may represent a novel approach for periodontitis treatment.

scholarly journals Gait Disorders In Patients After Polytrauma

2015 ◽  
Vol 69 (1-2) ◽  
pp. 27-32
Author(s):  
Ruta Jakušonoka ◽  
Zane Pavāre ◽  
Andris Jumtiņš ◽  
Aleksejs Smolovs ◽  
Tatjana Anaņjeva
Keyword(s):  
Ground Reaction Force ◽  
Knee Flexion ◽  
Reaction Force ◽  
Three Dimensional ◽  
Step Length ◽  
Vertical Load ◽  
Lower Limb Injuries ◽  
Limb Injuries ◽  
Stance Time ◽  
Polytrauma Patients

Abstract Evaluation of the gait of patients after polytrauma is important, as it indicates the ability of patients to the previous activities and work. The aim of our study was to evaluate the gait of patients with lower limb injuries in the medium-term after polytrauma. Three-dimensional instrumental gait analysis was performed in 26 polytrauma patients (16 women and 10 men; mean age 38.6 years), 14 to 41 months after the trauma. Spatio-temporal parameters, motions in pelvis and lower extremities joints in sagittal plane and vertical load ground reaction force were analysed. Gait parameters in polytrauma patients were compared with a healthy control group. Polytrauma patients in the injured side had decreased step length, cadence, hip extension, maximum knee flexion, vertical load ground reaction force, and increased stance time and pelvic anterior tilt; in the uninjured side they had decreased step length, cadence, maximum knee flexion, vertical load ground reaction force and increased stance time (p < 0.05). The use of the three-dimensional instrumental gait analysis in the evaluation of polytrauma patients with lower limb injuries consequences makes it possible to identify the gait disorders not only in the injured, but also in the uninjured side.

scholarly journals Numerical and Experimental Studies on a Three-Dimensional Numerical Wave Tank

IEEE Access ◽  
2018 ◽  
Vol 6 ◽  
pp. 6585-6593 ◽  
Author(s):  
Xiaojie Tian ◽  
Qingyang Wang ◽  
Guijie Liu ◽  
Wei Deng ◽  
Zhiming Gao
Keyword(s):  
Experimental Studies ◽  
Three Dimensional ◽  
Numerical Wave Tank ◽  
Wave Tank ◽  
Numerical Wave

scholarly journals The Application of Visual Environmental Economics in the Study of Public Preference and Urban Greenspace

2009 ◽  
Vol 36 (2) ◽  
pp. 355-375 ◽  
Author(s):  
Richard Laing ◽  
Anne-Marie Davies ◽  
David Miller ◽  
Anna Conniff ◽  
Stephen Scott ◽  
...  
Keyword(s):  
Environmental Economic ◽  
Environmental Economics ◽  
Environmental Conditions ◽  
Three Dimensional ◽  
Computer Models ◽  
Time Of Day ◽  
Public Preference ◽  
Daily Lives ◽  
Urban Greenspace ◽  
Physical Variables

Urban greenspace has consistently been argued to be of great importance to the wellbeing, health, and daily lives of residents and users. This paper reports results from a study that combined the visualisation of public results from a study that combined the visualisation of public greenspace with environmental economics, and that aimed to develop a method by which realistic computer models of sites could be used within preference studies. As part of a methodology that employed contingent rating to establish the values placed on specific greenspace sites, three-dimensional computer models were used to produce visualisations of particular environmental conditions. Of particular importance to the study was the influence of variables including lighting, season, time of day, and weather on the perception of respondents. This study followed previous work that established a suitable approach to the modelling and testing of entirely moveable physical variables within the built environment. As such, the study has established firmly that computer-generated visualisations are appropriate for use within environmental economic surveys, and that there is potential for a holistic range of attributes to be included in such studies.

Numerical Modeling of Tube Hydropiercing Using Phenomenological and Micro-Mechanical Damage Criteria

2013 ◽  
Vol 549 ◽  
pp. 172-179 ◽  
Author(s):  
Amir Hassannejadasl ◽  
Daniel E. Green
Keyword(s):  
Experimental Studies ◽  
Three Dimensional ◽  
Equivalent Plastic Strain ◽  
Mechanical Damage ◽  
High Strength ◽  
Dimensional Finite Element ◽  
Steel Dp600 ◽  
Three Dimensional Finite Element ◽  
Jc Model ◽  
Damage Criteria

Hydropiercing is an efficient way of piercing holes in mass produced hydroformed parts with complex geometries. By driving piercing punches radially into a hydroformed and fully pressurized tube, holes will be pierced and extruded into the tube-wall. Recent experimental studies have shown that the formability of advanced high strength steel (AHSS) tubes can be increased with the application of internal pressure. In this study, three-dimensional finite element simulations of a tube hydropiercing process of a dual phase steel (DP600) were performed in LS-DYNA, using phenomenological, micromechanical and combined damage criteria. Damage was included in the numerical analysis by applying constant equivalent plastic strain (CEPS), the Gurson-Tvergaard-Needleman (GTN), and the Extended GTN (GTN+JC) model. In order to calibrate the parameters in each model, a specialized hole-piercing fixture was designed and piercing tests were carried out on non-pressurized tube specimens. Of the various ductile fracture criteria, the results predicted with the GTN+JC model, such as the punch load-displacement, the roll-over depth, and the quality of the clearance zone correlated the best with the experimental data.

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