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38 projects in result set. Displaying 20 per page. Projects sorted by alphabetical order.
<1> <2>
Are subject-specific musculoskeletal models robust to parameter identification?
- This study analyzed the sensitivity of the predictions of an MRI-based musculoskeletal model (i.e., joint angles, joint moments, muscle and joint contact forces) during walking to the unavoidable uncertainties in parameter identification, i.e., body landmark positions, maximum muscle tension and musculotendon geometry. To this aim, we created an MRI-based musculoskeletal model of the lower limbs, defined as a 7-segment, 10-degree-of-freedom articulated linkage, actuated by 84 musculotendon units. We then performed a Monte-Carlo probabilistic analysis perturbing model parameters according to their uncertainty, and solving a typical inverse dynamics and static optimization problem using 500 models that included the different sets of perturbed variable values. Model creation and gait simulations were performed by using freely available software that we developed to standardize the process of model creation, integrate with OpenSim and create probabilistic simulations of movement. | |
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Activity Percentile: 93.13 Registered: 2014-11-10 15:19 |
Predicting Cell Deformation from Body Level Mechanical Loads
- This project is a NIBIB/NIH funded study (1R01EB009643-01) to establish models and computational platforms to predict cellular deformations from joint level mechanical loading.
Collaborators:
Ahmet Erdemir (PI), Amit Vasanji, Jason Halloran (Cleveland Clinic)
Cees Oomens, Frank Baaijens (Eindhoven University of Technology)
Jeff Weiss (University of Utah)
Farshid Guilak (Duke University)
Summary (from grant proposal):
Cells of the musculoskeletal system are known to have a biological response to deformation. Deformations, when abnormal in magnitude, duration, and/or frequency content, can lead to cell damage and possible disruption in homeostasis of the extracellular matrix. These mechanisms can be studied in an isolated fashion but connecting mechanical cellular response to organ level mechanics and human movement requires a multiscale approach. At the organ level, physicians perform surgical procedures, investigators try to understand risk of injury, and clinicians prescribe preventive and therapeutic interventions. Many of these operations are aimed at management and prevention of cell damage, and to associate joint level mechanical markers of failure to cell level failure mechanisms. Through human movement, one explores neuromuscular control mechanisms and the influence of physical activity on musculoskeletal tissue properties. At a lower level, mechanical sensation of cell deformations regulate movement control. Physical rehabilitation and exercise regimens are prescribed to promote tissue healing and/or strengthening through cellular regeneration. The knowledge of the mechanical pathway, through which the body level loads are distributed between organs, then within the tissues and further along the extracellular matrix and the cells, is critical for the success of various interventions. However, this information is not established. The goal of this research proposal is to portray that prediction of cell deformations from loads acting on the human body, therefore a clear depiction of the mechanical pathway, is possible, if a multiscale simulation approach is used. Multiresolution models of the knee joint, representative of joint, tissue and cell structure and mechanics, will be developed for this purpose. The knee endures high rates of traumatic injury to its soft tissue structures and it is predominantly affected by osteoarthritis, chronically induced by abnormalities in mechanical loading or how it is transferred to the cartilage. Through multiscale mechanical coupling of these models, a map of cellular deformation in cartilage, ligaments and menisci under a variety of tibiofemoral joint loads will be obtained. Comprehensive mechanical testing at joint, tissue and cell levels will be conducted for parameter estimation and validation, including in vitro loading of the knee joint representative of lifelike loading scenarios. In addition, imaging modalities will capture joint and tissue anatomy, and spatial and deformation related information from cell and extracellular matrix. Advanced computational approaches will be used to obtain model properties and to facilitate multiscale simulations. The approach will combine the expertise of many investigators experienced in biomechanical modeling and experimentation at various biological scales, some with clinical expertise. In future, the research team will utilize this platform to establish the relationship between the structural and loading state of the knee and chondrocyte stresses to explore potential mechanisms of cartilage degeneration. Through documented dissemination of data and models, simulations of other pathologies and translation of the methodology to other organs can be carried out by any interested investigator. | |
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Registered: 2009-07-23 17:33 |
Model of the Scapulothoracic Joint
- In this study, we developed a rigid-body model of a scapulothoracic joint to describe the kinematics of the scapula relative to the thorax. This model describes scapula kinematics with four degrees of freedom: 1) elevation and 2) abduction of the scapula on an ellipsoidal thoracic surface, 3) upward rotation of the scapula normal to the thoracic surface, and 4) internal rotation of the scapula to lift the medial border of the scapula off the surface of the thorax. The surface dimensions and joint axes can be customized to match an individual’s anthropometry. We compared the model to “gold standard” bone-pin kinematics collected during three shoulder tasks and found modeled scapula kinematics to be accurate to within 2 mm root-mean-squared error for individual bone-pin markers across all markers and movement tasks. As an additional test, we added random and systematic noise to the bone-pin marker data and found that the model reduced kinematic variability due to noise by 65% compared to Euler angles computed without the model. Our scapulothoracic joint model can be used for inverse and forward dynamics analyses and to compute joint reaction loads. The computational performance of the scapulothoracic joint model is well suited for real-time applications, is freely available as an OpenSim 3.2 plugin, and is customizable and usable with other OpenSim models. | |
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Activity Percentile: 88.55 Registered: 2015-01-14 23:10 |
Specimen-Specific Models of the Healthy Knee
- As part of research funded by the National Institutes of Health, National Institute of Biomedical Imaging and Bioengineering (NIBIB), investigators at the University of Denver Center for Orthopaedic Biomechanics have made available a repository of experimental, image, and computational modeling data from mechanical testing of natural human knee biomechanics. It is uncommon for such a comprehensive dataset to be obtained. Therefore, we have made this repository available to assist the greater research community interested in the complexities and pathologies of knee health and mechanical function. Data are provided for 7 human knees (5 cadaveric subjects) and fall under two categories:
Image Data and Experimental & Computational Modeling Data.
Additional details about the data can be found at:
http://ritchieschool.du.edu/research/centers-institutes/orthopaedic-biomechanics/downloads/natural-knee-data/
This repository of natural knee data has been made available thanks to funding from the National Institutes of Health through National Institute of Biomedical Imaging and Bioengineering R01-EB015497. | |
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Registered: 2008-06-12 23:15 |
Reference Models for Multi-Layer Tissue Structures
- This project aims to establish the founding knowledge, data and models for the mechanics of multi-layer tissue structures of the limbs, particularly of the lower and upper legs and arms. The activity is targeted to promote scientific research in layered tissue structures and allow reliable virtual surgery simulations for clinical training and certification.
This research and development project titled “Reference Models for Multi-Layer Tissue Structures" was conducted by the Cleveland Clinic Foundation and was made possible by a contract vehicle which was awarded and administered by the U.S. Army Medical Research & Materiel Command under award number: W81XWH-15-1-0232. The views, opinions and/or findings contained in this website are those of the authors and do not necessarily reflect the views of the Department of Defense and should not be construed as an official DoD/Army position, policy or decision unless so designated by other documentation. No official endorsement should be made. | |
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Registered: 2015-08-24 12:54 |
Musculoskeletal Representation of Large Repertoires of Hand Grasping in Primates
- The project aims to investigate and characterize the complex function of the primate hand at the musculoskeletal level. The OpenSim models used in this project enabled extracting joint angles from 27 degrees of freedom as well as length of 50 musculotendon units in the hand and upper extremity. Results demonstrated both a more compact representation and a higher decoding capacity of grasping tasks when movements were expressed in the muscle kinematics domain than when expressed in the joint kinematics domain. The OpenSim models in the project were adapted from the upper extremity model by Holzbaur et al., Ann.Biomed. Eng., 2005. | |
Activity Percentile: 66.41 Registered: 2015-02-10 15:59 |
Interaction Between Biology and Robotics
- In this project we study a salient feature of human motor skill learning that is the ability to exploit similarities across related tasks. We test this concept in forward dynamics simulations of multiple reaching movements of a musculoskeletal arm model with eleven muscles. The eleven muscle activation patterns are generated by a combination of parametrized muscle synergies, where these synergies encode a shared prior among multiple reaching directions. | |
Activity Percentile: 65.65 Registered: 2013-10-11 11:51 |
A three-dimensional musculoskeletal model of the dog
- The domestic dog is interesting to investigate because of their wide range of body size, body mass, and physique. In the last several years, the number of clinical and biomechanical studies on dog locomotion has increased. However, the relationship between body structure and joint load during locomotion, as well as between joint load and degenerative diseases of the locomotor system (e.g. dysplasia), are not sufficiently understood. Collecting this data through in vivo measurements/records of joint forces and loads on deep/small muscles is complex, invasive, and sometimes unethical. The use of detailed musculoskeletal models may help fill the knowledge gap. We describe here the methods we used to create a detailed musculoskeletal model with 84 degrees of freedom and 134 muscles. Our model has three key-features: three-dimensionality, scalability, and modularity. We tested the validity of the model by identifying forelimb muscle synergies of a beagle at walk. We used inverse dynamics and static optimization to estimate muscle activations based on experimental data. We identified three muscle synergy groups by using hierarchical clustering. The activation patterns predicted from the model exhibit good agreement with experimental data for most of the forelimb muscles. We expect that our model will speed up the analysis of how body size, physique, agility, and disease influence neuronal control and joint loading in dog locomotion. | |
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Registered: 2020-11-30 08:11 |
Cervical Spine Injury Mechanisms Analysis and Simulation in Sport
- This project provides the following models:
1) MASI: full body model for the analysis of cervical spine loading during a various set of activities. The MASI is an in-silico representation of a healthy subject, and includes:
a) a custom joint that allows scapula and clavicle coupled motion with respect to humeral elevation;
b) full body inertial parameters for dynamic analyses;
c) neck kinematics from Vasavada Head&Neck model
d) optimised neck muscle parameters representative of a healthy subject's neck strength.
2) THE RUGBY MODEL: this is rugby-specify version of the MASI, and was created to estimate cervical spine load in rugby activities and other sports impacts involving upper body contacts. It includes the same characteristics of the MASI model, but the inertial properties were changed and informed by a DEXA scan of a front row rugby player;
The previous model versions can be used for inverse analysis and simulations in order to estimate cervical spine internal loading during non-injurious scenarios.
3) THE RUGBY MODEL + IMPACT SPECIFIC BUSHING PARAMETERS: This updated version of The Rugby Model includes viscoelastic bushing elements implemented at the C2-C3 to C5-C6 joints validated for axial impacts (Silvestros et al., 2019) [10.1371/journal.pone.0216663]. This model can be used for forward simulation to explore cervical spine loading and injury mechanisms doing injurious events.
4) THE RUGBY MODEL + MRI-informed MUSCLE PARAMETERS: This updated version of The Rugby Model includes wrapping surfaces and updated muscle parameters, and can be used to calculate muscle lengths and moment arms, as well as the forces and moments around the cervical spine during non-injurious scenarios. | |
Activity Percentile: 61.45 Registered: 2015-01-02 16:19 |
Analysis of arm swing during human walking
- This project provides a simplified version of the UpperLowerBodySimple model from the ULB-project, which was adjusted with the purpose to decrease the run time of the simulations.
The adjusted model was used to determine arm swing kinematics (with and without muscle excitations) during human walking, with arm movements not exceeding 70 degrees of anteflexion or abduction. However, the adjusted_ULB model can be used for modeling and simulating kinematics and kinetics of all neuromusculoskeletal systems.
For an example of an arm swing simulation without muscle excitation we refer to the video below.
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Activity Percentile: 56.49 Registered: 2013-10-19 09:43 |
A predictive model of muscle excitations based on muscle modularity
- Humans can efficiently walk across a large variety of terrains and locomotion conditions with little or no mental effort. It has been hypothesized that the nervous system simplifies neuromuscular control by using muscle synergies, thus organizing multi-muscle activity into a small number of coordinative co-activation modules. With this project we want to investigate how muscle modularity is structured across a large repertoire of locomotion conditions including five different speeds and five different ground elevations. For this we have used the non-negative matrix factorization technique in order to explain EMG experimental data with a low-dimensional set of four motor components. This descriptive analysis was translated into a predictive model that could: 1) Estimate how motor components modulate across locomotion speeds and ground elevations. This implies not only estimating the non-negative factors temporal characteristics, but also the associated muscle weighting variations. 2) Estimate how the resulting muscle excitations modulate across novel locomotion conditions and subjects. | |
Activity Percentile: 35.88 Registered: 2015-08-12 06:11 |
Full Body Model to Perform Deep Squatting and High Hip Flexion Tasks
- This customized musculoskeletal is suitable for analysis with up to 138 degrees of hip flexion and 145 degrees of knee flexion and was based on the previously published model by Rajagopal et al. (2016) and Lai et al. (2017).
Four wrapping surfaces were updated:
Gmax1_at_pelvis
Gmax2_at_pelvis
KnExt_at_fem
KnExtVL_at_fem
Three wrapping surfaces were implemented:
Post_at_pelvis
Gmed_at_pelvis
Flex_at_femhead
To cite this article: Danilo S. Catelli, Mariska Wesseling, Ilse Jonkers & Mario Lamontagne (2019): A musculoskeletal model customized for squatting task, Computer Methods in Biomechanics and Biomedical Engineering, 22(1):21-24.
DOI: 10.1080/10255842.2018.1523396
Link to this article: https://doi.org/10.1080/10255842.2018.1523396 | |
Registered: 2017-11-08 18:33 |
Wrist Anatomy and Kinematics Data Collection
- <div align="justify">CT images of wrists from 90 healthy volunteers (43 males and 47 females) were acquired in various wrist positions. The outer cortical surfaces of the carpal bones, radius, and ulna in a 3D format, and each bone kinematics were calculated for each wrist position using a methodology described in the README file associated with the database. The database does not include soft tissue or the cartilage information of the wrist. Moreover, there is a MATLAB graphic user interface (GUI) available for you to observe the database. This dataset comes from four different NIH funding between 2001 and 2014.</div>
Please cite the work if you're using this database:
<div align="justify"><a href="https://onlinelibrary.wiley.com/doi/abs/10.1002/jor.24435">Akhbari, B., Moore, D. C., Laidlaw, D. H., Akelman, E., Weiss, A-P. C., Wolfe, S. W., Crisco, J. J., 2019. Predicting Carpal Bone Kinematics using an Expanded Digital Database of Wrist Carpal Bone Anatomy and Kinematics, Journal of Orthopaedic Research. DOI:10.1002/jor.24435</a></div>
If you want the pdf version of the manuscript, please send your request on <a href="http://bit.ly/2YU2tTh">ResearchGate</a>.
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Registered: 2019-02-25 19:48 |
Neuromusculoskeletal Modeling (NMSM) Pipeline
- <div style="display:inline-block"><a href="https://nmsm.rice.edu"><img src="https://nmsm.rice.edu/img/nmsm-pipeline-social-card.jpg" style="float:left;max-width:calc(100% - 40px);"></a></div>
Full project information is available at: https://nmsm.rice.edu. Please direct any inquiries about the NMSM Pipeline to us by posting your questions on this SimTK project forum or emailing nmsm@rice.edu.
Neuromusculoskeletal Modeling (NMSM) Pipeline is a set of tools for personalizing models and designing treatments for movement impairments and other pathologies.
The NMSM Pipeline consists of two toolsets:
Model Personalization - Personalize joint, muscle-tendon, neural control, and ground contact model properties.
Treatment Optimization - Design treatments using personalized models and an optimal control methodology.
At this time, Treatment Optimization requires the use of <a href="https://www.gpops2.com/">GPOPS-II optimal control solver</a>.
The NMSM Pipeline is written in MATLAB to lower the barrier for entry and to facilitate accessibility to the core codebase. We encourage users to modify the code to meet their needs.
The core codebase and examples are available to download for use in research. At this time, we ask that you wait to publish any work that uses the NMSM Pipeline until the journal article reference for the software is available. Please get in touch with us if you have any questions.
If you need help or want to start a discussion, please use the SimTK forum for this project.
Note: This project is a living entity. Updates will be made available as the Pipeline, examples, and tutorials are developed further and improved. | |
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Registered: 2022-07-07 14:55 |
Single Molecule Dwell-time Distributions
- Dwell-time distributions, waiting-time distributions, or distributions of pause durations are widely reported in single molecule biophysical experiments. Simplified models have enabled kinetic analyses of many systems, but they may misrepresent the data if reverse and branching kinetic pathways are present. We have developed a novel computational method that overcomes these limitations and can handle complex kinetic schemes. Furthermore this method can be used to globally fit data under different conditions with a single kinetic scheme. This method was originally developed for the analysis of single molecule dwell-time distributions of myosin V under different concentrations and optical trap forces.
Reference:
Liao, J.-C., Spudich, J.A., Parker, D., Delp, S.L. (2007) Extending the absorbing boundary method to fit dwell-time distributions of molecular motors with complex kinetic pathways. Proceedings of the National Academy of Sciences, USA, 104, 3171-3716.
http://www.pnas.org/cgi/content/abstract/104/9/3171 | |
Activity Percentile: 5.73 Registered: 2006-03-03 01:43 |
Spine Movement
- Generate Euler Angles and joint forces of vertebral bodies | |
Activity Percentile: 0.00 Registered: 2013-08-07 17:25 |
Acetaminophen Induced Liver Injury
- The AILI project is a type of In-Silico Liver (ISL) project, which consists of a body of Java code used and reused for exploring hypothetical liver mechanisms. For AILI, the liver mechanisms are those that cause cellular damage, specifically necrosis, because of exposure to acetaminophen. Moreover, the model, a mouse analog, is used for virtual experimentation to explore and explain AILI phenomena, analogous to wet-lab experimentation. A recent addition to this project is studying the disconnect between in vitro and in vivo wet-lab experiments by comparing and contrasting virtual Mouse and Culture Analogs. | |
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Activity Percentile: 0.00 Registered: 2015-05-07 23:25 |
A Cell-centered, Agent-based Framework with flexible Granularity
- Mechanistic explanations of cell-level phenomena rarely study behavior from a cell's perspective. Agent-based models lend themselves to model from an individual's perspective, and we extend that with a framework which utilizes a cell's perspective in an off-lattice environment. We aim to help increase the understanding of biological phenomena through our Delaunay and Voronoi off-lattice agent-based, discrete event framework. We focus on biological cells and expand on existing cell- and agent-centered methods by offering a new perspective in an off-lattice environment. | |
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Activity Percentile: 0.00 Registered: 2015-09-24 18:24 |
Biomechanics of soft tissues in human knee joint
- Abnormal loading of the knee joint could be a result of injuries to the joint tissues like the menisci and ligaments. This subsequently leads to abnormal body weight distribution in the knee joint causing excessive forces in some regions of the joint likely leading to osteoarthritis. It is important to know the functions and relationships that exists between the mechanical properties of the tissues in the knee joint. This work seeks to experimentally characterize the tensile and rupture properties of menisci, cartilage, ligaments and cartilage to determine their strain-, time- and site-specific properties. | |
Activity Percentile: 0.00 Registered: 2014-04-03 17:50 |
T cell calcium dynamics regulated by age-induced oxidation
- T cells reach a state of replicative senescence characterized by a decreased ability to proliferate and respond to foreign antigens. Calcium release associated with TCR engagement is widely used as a surrogate measure of T cell response. Using an ex vivo culture model that partially replicates features of organismal aging, we observe that while the amplitude of Ca2+ signaling does not change with time in culture, older T cells exhibit faster Ca2+ rise and a faster decay. Gene expression analysis of Ca2+ channels and pumps expressed in T cells by RT-qPCR identified overexpression of the plasma membrane CRAC channel subunit ORAI1 and PMCA in older T cells. To test whether overexpression of the plasma membrane Ca2+ channel is sufficient to explain the kinetic information, we adapted a previously published computational model by Maurya and Subramaniam to include additional details on the store-operated calcium entry (SOCE) process to recapitulate Ca2+ dynamics after T cell receptor stimulation. Simulations demonstrated that upregulation of ORAI1 and PMCA channels is not sufficient to explain the observed alterations in Ca2+ signaling. Instead, modeling analysis identified kinetic parameters associated with the IP3R and STIM1 channels as potential causes for alterations in Ca2+ dynamics associated with the long term ex vivo culturing protocol. Due to these proteins having known cysteine residues susceptible to oxidation, we subsequently investigated and observed transcriptional remodeling of metabolic enzymes, a shift to more oxidized redox couples, and post-translational thiol oxidation of STIM1. The model-directed findings from this study highlight changes in the cellular redox environment that may ultimately lead to altered T cell calcium dynamics during immunosenescence or organismal aging. | |
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Registered: 2016-07-01 17:00 |
38 projects in result set. Displaying 20 per page. Projects sorted by alphabetical order.
<1> <2>