1,721,634 research outputs found
A Model of Health: Mathematical modeling tools play an important role in optimizing new treatment options for heart disease
No full textTechniques for cardiac valve repair: simulation of patient specific postoperative scenarios for personalized surgical planning
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Nanomechanics of collagen microfibrils
Full text linkCollagen constitutes one third of the human proteome, providing mechanical stability, elasticity and strength to organisms and is thus the prime construction material in biology. Collagen is also the dominating material in the extracellular matrix where its stiffness controls cell differentiation, growth and pathology. We use atomistic-based hierarchical multiscale modeling to describe this complex biological material from the bottom up. This includes the use and development of large-scale computational modeling tools to investigate several aspects related to collagen-based tissues, including source of visco-elasticity and deformation mechanisms at the nanoscale level. The key innovation of this research is that until now, collagen materials have primarily been described at macroscopic scales, without explicitly understanding the mechanical contributions at the molecular and fibrillar levels. The major impact of this research will be the development of fundamental models of collagenous tissues, important to the design of new scaffolding biomaterials for regenerative medicine as well as for the understanding of collagen-related disease
Functional and Biomechanical Effects of the Edge-to-Edge Repair in the Setting of Mitral Regurgitation: Consolidated Knowledge and Novel Tools to Gain Insight into Its Percutaneous Implementation
Full text linkMitral regurgitation is the most prevalent heart valve disease in the western population. When severe, it requires surgical treatment, repair being the preferred option. The edge-to-edge repair technique treats mitral regurgitation by suturing the leaflets together and creating a double-orifice valve. Due to its relative simplicity and versatility, it has become progressively more widespread. Recently, its percutaneous version has become feasible, and has raised interest thanks to the positive results of the Mitraclip(®) device. Edge-to-edge features and evolution have stimulated debate and multidisciplinary research by both clinicians and engineers. After providing an overview of representative studies in the field, here we propose a novel computational approach to the most recent percutaneous evolution of the edge-to-edge technique. Image-based structural finite element models of three mitral valves affected by posterior prolapse were derived from cine-cardiac magnetic resonance imaging. The models accounted for the patient-specific 3D geometry of the valve, including leaflet compound curvature pattern, patient-specific motion of annulus and papillary muscles, and hyperelastic and anisotropic mechanical properties of tissues. The biomechanics of the three valves throughout the entire cardiac cycle was simulated before and after Mitraclip(®) implantation, assessing the biomechanical impact of the procedure. For all three simulated MVs, Mitraclip(®) implantation significantly improved systolic leaflets coaptation, without inducing major alterations in systolic peak stresses. Diastolic orifice area was decreased, by up to 58.9%, and leaflets diastolic stresses became comparable, although lower, to systolic ones. Despite established knowledge on the edge-to-edge surgical repair, latest technological advances make its percutanoues implementation a challenging field of research. The modeling approach herein proposed may be expanded to analyze clinical scenarios that are currently critical for Mitraclip(®) implantation, helping the search for possible solutions
A structural model of the left ventricle including muscle fibres and coronary vessels: mechanical behaviour in normal conditions.
No full textIntraventricular pressure drop and aortic blood acceleration as indices of cardiac inotropy: a comparison with the first derivative of aortic pressure based on computer fluid dynamics.
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Mesh updating in fluid-structure interactions in biomechanics: an iterative method based on an uncouple approach.
No full textBioengineering of the liver
Full text linkThe liver is an extremely complicated organ regulating the crucial
metabolic processes and immune homeostasis in the human body. It
performs various functions, such as carbohydrate, lipid, and amino
acid metabolism, ammonia clearance, urea synthesis, albumin and bile
acid synthesis, xenobiotic metabolism, and inflammatory response.1
Various pathogenic factors, including alcohol abuse, viral infection,
and autoimmune or metabolic disorders, promote functional disorders
of the liver, inducing acute or chronic inflammation, fibrosis, cirrhosis,
and even tumorigenesis. Meanwhile, the liver is located in a complicated mechanical or physical microenvironment that is critical for
maintaining physiological homeostasis, possessing mechanotransductive responses of various hepatic cells.2 Emerging bioengineering technologies enable efficient assessment and tests of liver physiopathology,
covering the fields of microfluidics, biomaterials, tissue engineering
and bioprinting, gene screening and genotyping, biomechanics and
mechanobiology, and others.3,4 The latest advances addressed include
organ-on-chips, organoids, gene sequencing, drug release profiling,
and cytotoxicity screening, providing an overview from basic research
to translation into practice and describing the most exciting challenges
and opportunities that multidisciplinary approaches can provide to
the field
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