Many biological soft tissues are structurally composed of a mostly isotropic matrix (elastin) and fibers (collagen). These fibers are not perfectly aligned but dispersed around some referential, preferred directions. In order to account for the dispersion of the fibers, a probability distribution is assumed. The Generalized Structure Tensor (GST) models perform a pre-integration of the distribution in order to achieve improved computational efficiency. The best known model of this kind is the Gasser-Ogden-Holzapfel (GOH) model. However, in these models no singular treatment of fibers is made. Whenever they suffer compression it is usual to consider that fibers should not contribute to the overall stiffness. At this point, a switch criterion is employed. This switch criterion is important because it changes the model predictions and may also result in unphysical stress predictions or strain ranges at which no compatible equilibrium solution is found. We perform an analysis of different tension-compression switch criteria from the literature for the GOH model and show relevant physical and computational drawbacks when using these criteria. In order to overcome these drawbacks, we make a new proposal which yields continuous stress solutions. In our proposal, pre-integrated expressions given in terms of the usual set of invariants take into account an average amount of fibers working either in tension or in compression for a given deformation gradient and fiber family. Two distinct switches naturally emerge from our procedure. Furthermore, we keep the appealing GST pre-integrated approach for any proposed stored energy, including that of the GOH model.
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http://dx.doi.org/10.1016/j.jmbbm.2015.11.018 | DOI Listing |
J Adv Nurs
January 2025
Alice Lee Centre for Nursing Studies, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore.
Aims: This study aims to identify factors associated with mental health literacy (mental health knowledge and attitudes towards mental health and help-seeking behaviours), depression and anxiety amongst adolescents, and test the hypothesised model by examining the interrelationships between these outcomes.
Design: Cross-sectional descriptive quantitative research.
Methods: Using convenient sampling, 615 adolescents from four public schools completed online questionnaires measuring mental health literacy, depression, and anxiety.
Laryngoscope
January 2025
Department of Otolaryngology - Head & Neck Surgery, National University Hospital, Singapore, Singapore.
Objective: The efficacy of the transcanal endoscopic approach in tympanoplasty, cholesteatoma removal, and stapedotomy is detailed. This study reviews evidence on the feasibility of endoscopic ossiculoplasty as a suitable alternative to traditional microscopic ossiculoplasty.
Data Sources: PubMed, Embase, and Cochrane Library were searched from inception to 19 June 2024 for articles comparing endoscopic and microscopic ossicular chain reconstruction.
Gut Liver
January 2025
Department of Gastroenterology and Hepatology, Singapore General Hospital, Singapore.
Metabolic dysfunction-associated steatotic liver disease (MASLD), is the most common cause of liver disease, and its burden on health systems worldwide continues to rise at an alarming rate. MASLD is a complex disease in which the interactions between susceptible genes and the environment influence the disease phenotype and severity. Advances in human genetics over the past few decades have provided new opportunities to improve our understanding of the multiple pathways involved in the pathogenesis of MASLD.
View Article and Find Full Text PDFPLoS One
January 2025
Department of Medicine, Faculty of Medicine, Universiti Malaya, Kuala Lumpur, Malaysia.
Int Psychogeriatr
June 2024
Department of Primary and Community Care, Radboud University Medical Center, Nijmegen, The Netherlands.
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