The goal of this study was to determine how alterations in protein composition of the extracellular matrix (ECM) affect its functional properties. To achieve this, we investigated the changes in the mechanical and failure properties of ECM sheets generated by neonatal rat aortic smooth muscle cells engineered to contain varying amounts of collagen and elastin. Samples underwent static and dynamic mechanical measurements before, during, and after 30 min of elastase digestion followed by a failure test. Microscopic imaging was used to measure thickness at two strain levels to estimate the true stress and moduli in the ECM sheets. We found that adding collagen to the ECM increased the stiffness. However, further increasing collagen content altered matrix organization with a subsequent decrease in the failure strain. We also introduced collagen-related percolation in a nonlinear elastic network model to interpret these results. Additionally, linear elastic moduli correlated with failure stress which may allow the in vivo estimation of the stress tolerance of ECM. We conclude that, in engineered replacement tissues, there is a tradeoff between improved mechanical properties and decreased extensibility, which can impact their effectiveness and how well they match the mechanical properties of native tissue.
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http://dx.doi.org/10.1529/biophysj.107.107144 | DOI Listing |
Respir Res
January 2025
School of Engineering, University of Warwick, Coventry, CV4 7AL, UK.
Introduction And Objectives: High flow nasal cannula (HFNC) therapy is an increasingly popular mode of non-invasive respiratory support for the treatment of patients with acute hypoxemic respiratory failure (AHRF). Previous experimental studies in healthy subjects have established that HFNC generates flow-dependent positive airway pressures, but no data is available on the levels of mean airway pressure (mP) or positive end-expiratory pressure (PEEP) generated by HFNC therapy in AHRF patients. We aimed to estimate the airway pressures generated by HFNC at different flow rates in patients with AHRF, whose functional lung volume may be significantly reduced compared to healthy subjects due to alveolar consolidation and/or collapse.
View Article and Find Full Text PDFBMC Oral Health
January 2025
Department of Fixed Prosthodontics - Faculty of Dentistry, Ain Shams University, Organization of African Unity, St, El-Qobba Bridge, El Weili, Cairo Governorate, Egypt.
Background: Home bleaching is a promising option for addressing discolored teeth conservatively. However, its impact on the physical and mechanical properties of indirect restorations remains unknown. This study provides comparative insights into the material responses to aesthetic treatments by assessing the effects of home bleaching agents on two hybrid ceramics: VITA ENAMIC and Grandio Blocs.
View Article and Find Full Text PDFAnn Intensive Care
January 2025
Department of Intensive Care, Erasmus MC, P.O. Box 2040, 3000 CA, Rotterdam, The Netherlands.
Background: Extubation failure is associated with an increased morbidity, emphasizing the need to identify factors to further optimize extubation practices. The role of biomarkers in the prediction of extubation failure is currently limited. The aim of this study was to investigate the prognostic value of cardiac (N-terminal pro-B-type natriuretic peptide (NT-proBNP), High-sensitivity Troponin T (Hs-TnT)) and inflammatory biomarkers (Interleukin-6 (IL-6) and Procalcitonin (PCT)) for extubation failure in patients with COVID-19 Acute Respiratory Distress Syndrome (C-ARDS).
View Article and Find Full Text PDFBMJ Open
January 2025
Department of Cardiac Surgery, Assistance Publique-Hôpitaux de Paris, Creteil, France.
Background: Secondary mitral regurgitation (SMR) is a condition affecting the left ventricle (LV) rather than the mitral valve (MV). If the MV remains structurally unchanged, enlargement of the LV or impairment of the papillary muscles can occur. Several mechanical interventions are available to dictate the resolution of MR.
View Article and Find Full Text PDFJ Dent
January 2025
Senior Research and Teaching Assistant, Clinic of Reconstructive Dentistry, Center for Dental Medicine, University of Zurich, Plattenstrasse 11, 8032 Zurich, Switzerland. Electronic address:
Objectives: A new abutment-free implant connection allows for direct screwing of FDPs on implants to avoid complications caused by cement rests or screw loosening, which may affect to screw torque and load distribution. The objective of this study was to test the initial (Fi) and final failure (Ff) loads and torque changes of abutment-free monolithic zirconia CAD-CAM fixed dental prostheses (FDPs) compared to titanium FDPs on different abutment designs.
Methods: Three-unit screw-retained FDPs (n=50) on two implants (n=100) were divided into groups (n=10) based on the implant-abutment connection and material of the supra-structure: (1) abutment-free monolithic CAD-CAM zirconia FDP (Abut-free-Zr), (2) abutment-free veneered titanium FDPs (Abut-free-Ti), (3) monolithic zirconia FDPs with titanium base abutments (Zr-Ti-Base), (4) monolithic zirconia FDPs on multi-unit abutments (Zr-MU), (5) veneered titanium FDP on multi-unit abutments (Ti-MU).
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