Blar i NTNU Open på forfatter "Holzapfel, Gerhard"
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A family of hyperelastic models for human brain tissue
Mihai, L Angela; Budday, Silvia; Holzapfel, Gerhard; Kuhl, Ellen; Goriely, Alain (Journal article; Peer reviewed, 2017)Experiments on brain samples under multiaxial loading have shown that human brain tissue is both extremely soft when compared to other biological tissues and characterized by a peculiar elastic response under combined shear ... -
An exponential constitutive model excluding fibres under compression: Application to extension–inflation of a residually stressed carotid artery
Li, Kewei; Ogden, Ray W; Holzapfel, Gerhard (Journal article; Peer reviewed, 2018)Detailed information on the three-dimensional dispersion of collagen fibres within layers of healthy and diseased soft biological tissues has been reported recently. Previously we have proposed a constitutive model for ... -
An arterial constitutive model accounting for collagen content and cross-linking
Holzapfel, Gerhard; Ogden, Ray W (Peer reviewed; Journal article, 2020)It is apparent from the literature that the density of cross-links in collagenous tissue has a stiffening effect on the mechanical response of the tissue. This paper represents an initial attempt to characterize this effect ... -
Biomechanical characterization of a chronic type a dissected human aorta
Amabili, Marco; Arena, Goffredo O.; Balasubramanian, Prabakaran; Breslavsky, Ivan D.; Cartier, Raymond; Ferrari, Giovanni; Holzapfel, Gerhard; Kassab, Ali; Mongrain, Rosaire (Peer reviewed; Journal article, 2020)Aortic dissection is one of the most lethal cardiovascular diseases. A chronic Type A (Stanford) dissected aorta was retrieved for research from a 73-year-old male donor without diagnosed genetic disease. The aorta presented ... -
Biomechanical properties of native and cultured red blood cells–Interplay of shape, structure and biomechanics
Bernecker, Claudia; Lima, Maria; Kolesnik, Tatjana; Lampl, Annika; Ciubotaru, Catalin; Leita, Riccardo; Kolb, Dagmar; Fröhlich, Eleonore; Schlenke, Peter; Holzapfel, Gerhard; Dorn, Isabel; Cojoc, Dan (Peer reviewed; Journal article, 2022)Modern medicine increases the demand for safe blood products. Ex vivo cultured red blood cells (cRBC) are eagerly awaited as a standardized, safe source of RBC. Established culture models still lack the terminal cytoskeletal ... -
Biomechanics of degenerative mitral valve leaflets: Mechanical behavior, collagen structure, and numerical simulations
Sadeghinia, Mohammad Javad (Doctoral theses at NTNU;2023:395, Doctoral thesis, 2023)Degenerative mitral valve disease impacts around 2% of the population and leads to mitral regurgitation because of valvular incompetence. Two distinct phenotypes of degenerative mitral valve disease are fibroelastic ... -
Biomechanics of mitral valve leaflets: Second harmonic generation microscopy, biaxial mechanical tests and tissue modeling
Sadeghinia, MohammadJavad; Skallerud, Bjørn Helge; Holzapfel, Gerhard; Prot, Victorien Emile (Peer reviewed; Journal article, 2022)Collagen fibers are the main load carrier in the mitral valve (MV) leaflets. Their orientation and dispersion are an important factor for the mechanical behavior. Most recent studies of collagen fibers in MVs lack either ... -
Cholesterol Deficiency Causes Impaired Osmotic Stability of Cultured Red Blood Cells
Bernecker, Claudia; Köfeler, Harald; Pabst, Georg; Trötzmüller, Martin; Kolb, Dagmar; Strohmayer, Karl; Trajanoski, Slave; Holzapfel, Gerhard; Schlenke, Peter; Dorn, Isabel (Journal article; Peer reviewed, 2019)Ex vivo generation of red blood cells (cRBCs) is an attractive tool in basic research and for replacing blood components donated by volunteers. As a prerequisite for the survival of cRBCs during storage as well as in the ... -
Compressibility and Anisotropy of the Ventricular Myocardium: Experimental Analysis and Microstructural Modeling
McEvoy, Eoin; Holzapfel, Gerhard; McGarry, Patrick (Journal article; Peer reviewed, 2018)is observed at a peak stretch of 1.3. Confined compression experiments also demonstrate significant volume change in the tissue (loading applied up to a volumetric strain of 10%). In order to simulate the multiaxial passive ... -
Deficiency of B vitamins leads to cholesterol-independent atherogenic transformation of the aorta
Almer, Gunter; Opriessnig, Peter; Wolinski, Heimo; Sommer, Gerhard; Diwoky, Clemens; Lechleitner, Margarete; Kolb, Dagmar; Bubalo, Vladimir; Brunner, Markus S.; Schwarz, Andreas N.; Leitinger, Gerd; Schoiswohl, Gabriele; Marsche, Gunther; Niedrist, Tobias; Schauer, Silvia; Oswald, Wolfgang; Groselj-Strele, Andrea; Paar, Margret; Cvirn, Gerhard; Hoefler, Gerald; Rechberger, Gerald N.; Herrmann, Markus; Frank, Saša; Holzapfel, Gerhard; Kratky, Dagmar; Mangge, Harald; Hörl, Gerd; Tehlivets, Oksana (Peer reviewed; Journal article, 2022)Atherosclerosis, the leading cause of cardiovascular disease responsible for the majority of deaths worldwide, cannot be sufficiently explained by established risk factors, including hypercholesterolemia. Elevated plasma ... -
Detection, segmentation, simulation and visualization of aortic dissections: A review
Pepe, Antonio; Li, Jianning; Rolf-Pissarczyk, Malte; Gsaxner, Christina; Chen, Xiaojun; Holzapfel, Gerhard; Egger, Jan (Peer reviewed; Journal article, 2020)Aortic dissection (AD) is a condition of the main artery of the human body, resulting in the formation of a new flow channel, or false lumen. The disease is usually diagnosed with a computed tomography angiography scan ... -
An efficient and accurate method for modeling nonlinear fractional viscoelastic biomaterials
Zhang, Will; Capilnasiu, Adela; Sommer, Gerhard; Holzapfel, Gerhard; Nordsletten, David A. (Peer reviewed; Journal article, 2020)While experimental evidence indicates that the mechanical response of most tissues is viscoelastic, current biomechanical models in the computational community often assume hyperelastic material models. Fractional viscoelastic ... -
Fourier transform-based method for quantifying the three-dimensional orientation distribution of fibrous units
Alberini, Riccardo; Spagnoli, Andrea; Sadeghinia, Mohammed Javad; Skallerud, Bjørn Helge; Terzano, Michele; Holzapfel, Gerhard (Peer reviewed; Journal article, 2024)Several materials and tissues are characterized by a microstructure composed of fibrous units embedded in a ground matrix. In this paper, a novel three-dimensional (3D) Fourier transform-based method for quantifying the ... -
Genetic deletion of MMP12 ameliorates cardiometabolic disease by improving insulin sensitivity, systemic inflammation, and atherosclerotic features in mice
Amor, Melina; Bianco, Valentina; Buerger, Martin; Lechleitner, Margarete; Vujić, Nemanja; Dobrijević, Anja; Akhmetshina, Alena; Pirchheim, Anita; Schwarz, Birgit; Pessentheiner, Ariane R.; Baumgartner, Franziska; Rampitsch, Katharina; Schauer, Silvia; Klobučar, Iva; Degoricija, Vesna; Pregartner, Gudrun; Kummer, Daniel; Svecla, Monika; Sommer, Gerhard; Kolb, Dagmar; Holzapfel, Gerhard; Hoefler, Gerald; Frank, Saša; Norata, Giuseppe Danilo; Kratky, Dagmar (Journal article; Peer reviewed, 2023)Background Matrix metalloproteinase 12 (MMP12) is a macrophage-secreted protein that is massively upregulated as a pro-inflammatory factor in metabolic and vascular tissues of mice and humans suffering from cardiometabolic ... -
Integration of polarized spatial frequency domain imaging (pSFDI) with a biaxial mechanical testing system for quantification of load-dependent collagen architecture in soft collagenous tissues
Jett, Samuel; Hudson, Luke; Baumwart, Ryan; Bohnstedt, Bradley; Mir, Arshid; Burkhart, Harold; Holzapfel, Gerhard; Wu, Yi; Lee, Chung-Hao (Peer reviewed; Journal article, 2020)Collagen fiber networks provide the structural strength of tissues, such as tendons, skin and arteries. Quantifying the fiber architecture in response to mechanical loads is essential towards a better understanding of the ... -
Mechanical behavior and collagen structure of degenerative mitral valve leaflets and a finite element model of primary mitral regurgitation
Sadeghinia, Mohammadjavad; Aguilera, Hans Martin Dahl; Urheim, Stig; Persson, Robert; Ellensen, Vegard Skalstad; Haaverstad, Rune; Holzapfel, Gerhard; Skallerud, Bjørn Helge; Prot, Victorien Emile (Peer reviewed; Journal article, 2023)Degenerative mitral valve disease is the main cause of primary mitral regurgitation with two phenotypes: fibroelastic deficiency (FED) often with localized myxomatous degeneration and diffuse myxomatous degeneration or ... -
Mechanics of Porcine Heart Valves’ Strut Chordae Tendineae Investigated as a Leaflet–Chordae–Papillary Muscle Entity
Ross, Colton; Laurence, Devin; Hsu, Ming-Chen; Baumwart, Ryan; Zhao, Yan; Mir, Arshid; Burkhart, Harold; Holzapfel, Gerhard; Wu, Yi; Lee, Chung-Hao (Peer reviewed; Journal article, 2020)Proper blood flow through the atrioventricular heart valves (AHVs) relies on the holistic function of the valve and subvalvular structures, and a failure of any component can lead to life-threatening heart disease. A ... -
Modeling fibrous biological tissues with a general invariant that excludes compressed fibers
Li, Kewei; Ogden, Ray W; Holzapfel, Gerhard (Journal article; Peer reviewed, 2018)Dispersed collagen fibers in fibrous soft biological tissues have a significant effect on the overall mechanical behavior of the tissues. Constitutive modeling of the detailed structure obtained by using advanced imaging ... -
Modeling the porous and viscous responses of human brain tissue behavior
Comellas, Ester; Budday, Silvia; Pelteret, Jean-Paul; Holzapfel, Gerhard; Steinmann, Paul (Peer reviewed; Journal article, 2020)The biomechanical characterization of human brain tissue and the development of appropriate mechanical models is crucial to provide realistic computational predictions that can assist personalized treatment of neurological ... -
Numerical analysis of the impact of cytoskeletal actin filament density alterations onto the diffusive vesicle-mediated cell transport
Haspinger, Daniel C.; Klinge, Sandra; Holzapfel, Gerhard (Peer reviewed; Journal article, 2021)The interior of a eukaryotic cell is a highly complex composite material which consists of water, structural scaffoldings, organelles, and various biomolecular solutes. All these components serve as obstacles that impede ...