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Parker Matthew D. Babarenda Gamage Thiranja P. HajiRassouliha Amir Taberner Andrew J. Nash Martyn P. Nielsen Poul M. F. 《Biomechanics and modeling in mechanobiology》2019,18(4):1031-1045
Biomechanics and Modeling in Mechanobiology - Many computer vision algorithms have been presented to track surface deformations, but few have provided a direct comparison of measurements with other... 相似文献
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Chris Bradley Andy BoweryRandall Britten Vincent BudelmannOscar Camara Richard ChristieAndrew Cookson Alejandro F. Frangi Thiranja Babarenda GamageThomas Heidlauf Sebastian KrittianDavid Ladd Caton LittleKumar Mithraratne Martyn Nash David NickersonPoul Nielsen Øyvind NordbøStig Omholt Ali Pashaei David PatersonVijayaraghavan Rajagopal Adam ReeveOliver Röhrle Soroush SafaeiRafael Sebastián Martin Steghöfer Tim WuTing Yu Heye ZhangPeter Hunter 《Progress in biophysics and molecular biology》2011,107(1):32-47
The VPH/Physiome Project is developing the model encoding standards CellML (cellml.org) and FieldML (fieldml.org) as well as web-accessible model repositories based on these standards (models.physiome.org). Freely available open source computational modelling software is also being developed to solve the partial differential equations described by the models and to visualise results. The OpenCMISS code (opencmiss.org), described here, has been developed by the authors over the last six years to replace the CMISS code that has supported a number of organ system Physiome projects.OpenCMISS is designed to encompass multiple sets of physical equations and to link subcellular and tissue-level biophysical processes into organ-level processes. In the Heart Physiome project, for example, the large deformation mechanics of the myocardial wall need to be coupled to both ventricular flow and embedded coronary flow, and the reaction-diffusion equations that govern the propagation of electrical waves through myocardial tissue need to be coupled with equations that describe the ion channel currents that flow through the cardiac cell membranes.In this paper we discuss the design principles and distributed memory architecture behind the OpenCMISS code. We also discuss the design of the interfaces that link the sets of physical equations across common boundaries (such as fluid-structure coupling), or between spatial fields over the same domain (such as coupled electromechanics), and the concepts behind CellML and FieldML that are embodied in the OpenCMISS data structures. We show how all of these provide a flexible infrastructure for combining models developed across the VPH/Physiome community. 相似文献
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Thomas Heidlauf Thomas Klotz Christian Rode Ekin Altan Christian Bleiler Tobias Siebert Oliver Röhrle 《Biomechanics and modeling in mechanobiology》2016,15(6):1423-1437
Although recent research emphasises the possible role of titin in skeletal muscle force enhancement, this property is commonly ignored in current computational models. This work presents the first biophysically based continuum-mechanical model of skeletal muscle that considers, in addition to actin–myosin interactions, force enhancement based on actin–titin interactions. During activation, titin attaches to actin filaments, which results in a significant reduction in titin’s free molecular spring length and therefore results in increased titin forces during a subsequent stretch. The mechanical behaviour of titin is included on the microscopic half-sarcomere level of a multi-scale chemo-electro-mechanical muscle model, which is based on the classic sliding-filament and cross-bridge theories. In addition to titin stress contributions in the muscle fibre direction, the continuum-mechanical constitutive relation accounts for geometrically motivated, titin-induced stresses acting in the muscle’s cross-fibre directions. Representative simulations of active stretches under maximal and submaximal activation levels predict realistic magnitudes of force enhancement in fibre direction. For example, stretching the model by 20 % from optimal length increased the isometric force at the target length by about 30 %. Predicted titin-induced stresses in the muscle’s cross-fibre directions are rather insignificant. Including the presented development in future continuum-mechanical models of muscle function in dynamic situations will lead to more accurate model predictions during and after lengthening contractions. 相似文献
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Gayathri Babarenda Gamage Carol Boyle Sarah J. McLaren Jake McLaren 《The International Journal of Life Cycle Assessment》2008,13(5):401-411
Background, aims and scope The environmental aspects of companies and their products are becoming more significant in delivering competitive advantage.
Formway Furniture, a designer and manufacturer of office furniture products, is a New Zealand-based company that is committed
to sustainable development. It manufactures two models of the light, intuitive, flexible and environmental (LIFE) office chair:
one with an aluminium base and one with a glass-filled nylon (GFN) base. It was decided to undertake a life cycle assessment
(LCA) study of these two models in order to: (1) determine environmental hotspots in the life cycle of the two chairs (goal
1); (2) compare the life cycle impacts of the two chairs (goal 2); and (3) compare alternative potential waste-management
scenarios (goal 3). The study also included sensitivity analysis with respect to recycled content of aluminium in the product.
Materials and methods The LIFE chair models consist of a mix of metal and plastic components manufactured by selected Formway suppliers according
to design criteria. Hence, the research methodology included determining the specific material composition of the two chair
models and acquisition of manufacturing data from individual suppliers. These data were compiled and used in conjunction with
pre-existing data, specifically from the ecoinvent database purchased in conjunction with the SimaPro7 LCA software, to develop
the life cycle inventory of the two chair models. The life cycle stages included in the study extended from raw-material extraction
through to waste management. Impact assessment was carried out using CML 2 baseline 2000, the methodology developed by Leiden
University’s Institute for Environmental Sciences.
Results This paper presents results for global warming potential (GWP100). The study showed a significant impact contribution from
the raw-material extraction/refinement stage for both chair models; aluminium extraction and refining made the greatest contribution
to GWP100. The comparison of the two LIFE chair models showed that the model with the aluminium base had a higher GWP100 impact
than the model with the GFN base. The waste-management scenario compared the GWP100 result when (1) both chair models were
sent to landfill and (2) steel and aluminium components were recycled with the remainder of the chair sent to landfill. The
results showed that the recycling scenario contributed to a reduced GWP100 result. Since production and processing of aluminium
was found to be significant, a sensitivity analysis was carried out to determine the impact of using aluminium with different
recycled contents (0%, 34% and 100%) in both waste-management scenarios; this showed that increased use of recycled aluminium
was beneficial. The recycling at end-of-life scenarios was modelled using two different end-of-life allocation approaches,
i.e. consequential and attributional, in order to illustrate the variation in results caused by choice of allocation approach.
The results using the consequential approach showed that recycling at end-of-life was beneficial, while use of the attributional
method led to a similar GWP100 as that seen for the landfill scenario.
Discussion The results show that the main hotspot in the life cycle is the raw-material extraction/refinement stage. This can be attributed
to the extraction and processing of aluminium, a material that is energy intensive. The LIFE chair model with the aluminium
base has a higher GWP100 as it contains more aluminium. Sensitivity analysis pertaining to the recycled content of aluminium
showed that use of aluminium with high recycled content was beneficial; this is because production of recycled aluminium is
less energy intensive than production of primary aluminium. The waste-management scenario showed that recycling at end-of-life
resulted in a significantly lower GWP100 than landfilling at end-of-life. However, this result is dependent upon the modelling
approach used for recycling.
Conclusions With respect to goal 1, the study found that the raw-material extraction/refinement stage of the life cycle was a significant
factor for both LIFE chair models. This was largely due to the use of aluminium in the product. For goal 2, it was found that
the LIFE chair model with the aluminium base had a higher GWP100 than the GFN model, again due to the material content of
the two models. Results for goal 3 illustrated that recycling at end-of-life is beneficial when using a system expansion (consequential)
approach to model recycling; if an attributional ‘cut-off’ approach is used to model recycling at end-of-life, there is virtually
no difference in the results between landfilling and recycling. Sensitivity analysis pertaining to the recycled content of
aluminium showed that use of higher recycled contents leads to a lower GWP100 impact.
Recommendation and perspectives Most of the GWP100 impact was contributed during the raw-material extraction/refinement stage of the life cycle; thus, the
overall impact of both LIFE chair models may be reduced through engaging in material choice and supply chain environmental
management with respect to environmental requirements. The study identified aluminium components as a major contributor to
GWP100 for both LIFE chair models and also highlighted the sensitivity of the results to its recycled content. Thus, it is
recommended that the use of aluminium in future product designs be limited unless it is possible to use aluminium with a high
recycled content. With respect to waste management, it was found that a substantial reduction in the GWP100 impact would occur
if the chairs are recycled rather than landfilled, assuming an expanding market for aluminium. Thus, recycling the two LIFE
chair models at end-of-life is highly recommended. 相似文献
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