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Author Aybar, M.; Perez-Calleja, P.; Li, M.; Pavissich, J.P.; Nerenberg, R. pdf  doi
openurl 
  Title Predation creates unique void layer in membrane-aerated biofilms Type
  Year 2019 Publication Water Research Abbreviated Journal Water Res.  
  Volume 149 Issue Pages 232-242  
  Keywords MABR; Biofilm; Protozoa; Predation; Voids; Porosity  
  Abstract The membrane-aerated biofilm reactor (MABR) is a novel wastewater treatment technology based on oxygen-supplying membranes. The counter diffusion of oxygen and electron donors in MABRs leads to unique behavior, and we hypothesized it also could impact predation. We used optical coherence tomography (OCT), microsensor analyses, and mathematical modeling to investigate predation in membrane-aerated biofilms (MABs). When protozoa were excluded from the inoculum, the MAB's OCT-observable void fraction was around 5%. When protozoa were included, the void fraction grew to nearly 50%, with large, continuous voids at the base of the biofilm. Real-time OCT imaging showed highly motile protozoa in the voids. MABs with protozoa and a high bulk COD (270 mg/L) only had 4% void fraction. DNA sequencing revealed a high relative abundance of amoeba in both high and low-COD MABs. Flagellates were only abundant in the low-COD MAB. Modeling also suggested a relationship between substrate concentrations, diffusion mode (co- or counter-diffusion), and bioflim void fraction. Results suggest that amoeba proliferate in the bioflim interior, especially in the aerobic zones. Voids form once COD limitation at the base of MABs allows predation rates to exceed microbial growth rates. Once formed, the voids provide a niche for motile protozoa, which expand the voids into a large, continuous gap. This increases the potential for biofilm sloughing, and may have detrimental effects on slow-growing, aerobic microorganisms such as nitrifying bacteria. (C)2018 Elsevier Ltd. All rights reserved.  
  Address [Aybar, M.; Perez-Calleja, P.; Li, M.; Pavissich, J. P.; Nerenberg, R.] Univ Notre Dame, Dept Civil & Environm Engn & Earth Sci, 156 Fitzpatrick Hall, Notre Dame, IN 46556 USA, Email: maybar@udec.cl;  
  Corporate Author Thesis  
  Publisher Pergamon-Elsevier Science Ltd Place of Publication Editor  
  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0043-1354 ISBN Medium  
  Area Expedition Conference  
  Notes WOS:000458221200023 Approved  
  Call Number UAI @ eduardo.moreno @ Serial 1166  
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Author Baler, R.V.; Wijnhoven, I.B.; del Valle, V.I.; Giovanetti, C.M.; Vivanco, J.F. pdf  doi
openurl 
  Title Microporosity Clustering Assessment in Calcium Phosphate Bioceramic Particles Type
  Year 2019 Publication Frontiers In Bioengineering And Biotechnology Abbreviated Journal Front. Bioeng. Biotechnol.  
  Volume 7 Issue 281 Pages 7 pp  
  Keywords calcium phosphate; bioceramic particle; microporosity; data mining; K-means clustering  
  Abstract There has been an increase in the application of different biomaterials to repair hard tissues. Within these biomaterials, calcium phosphate (CaP) bioceramics are suitable candidates, since they can be biocompatible, biodegradable, osteoinductive, and osteoconductive. Moreover, during sintering, bioceramic materials are prone to form micropores and undergo changes in their surface topographical features, which influence cellular physiology and bone ingrowth. In this study, five geometrical properties from the surface of CaP bioceramic particles and their micropores were analyzed by data mining techniques, driven by the research question: what are the geometrical properties of individual micropores in a CaP bioceramic, and how do they relate to each other? The analysis not only shows that it is feasible to determine the existence of micropore clusters, but also to quantify their geometrical properties. As a result, these CaP bioceramic particles present three groups of micropore clusters distinctive by their geometrical properties. Consequently, this new methodological clustering assessment can be applied to advance the knowledge about CaP bioceramics and their role in bone tissue engineering.  
  Address [Vallejos Baler, Raul; Irribarra del Valle, Victor; Vivanco, Juan F.] Adolfo Ibanez Univ, Fac Engn & Sci, Vina Del Mar, Chile, Email: juan.vivanco@uai.cl  
  Corporate Author Thesis  
  Publisher Frontiers Media Sa Place of Publication Editor  
  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 2296-4185 ISBN Medium  
  Area Expedition Conference  
  Notes WOS:000495370600001 Approved  
  Call Number UAI @ eduardo.moreno @ Serial 1062  
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Author Contreras-Raggio, J.I.; Arancibia, C.T.; Millan, C.; Ploeg, H.L.; Aiyangar, A.; Vivanco, J.F. doi  openurl
  Title Height-to-Diameter Ratio and Porosity Strongly Influence Bulk Compressive Mechanical Properties of 3D-Printed Polymer Scaffolds Type
  Year 2022 Publication Polymers Abbreviated Journal Polymers  
  Volume 14 Issue 22 Pages 5017  
  Keywords polymer scaffolds; 3D printing; height; diameter ratio; porosity; pore size; mechanical properties  
  Abstract Although the architectural design parameters of 3D-printed polymer-based scaffolds-porosity, height-to-diameter (H/D) ratio and pore size-are significant determinants of their mechanical integrity, their impact has not been explicitly discussed when reporting bulk mechanical properties. Controlled architectures were designed by systematically varying porosity (30-75%, H/D ratio (0.5-2.0) and pore size (0.25-1.0 mm) and fabricated using fused filament fabrication technique. The influence of the three parameters on compressive mechanical properties-apparent elastic modulus E-app, bulk yield stress sigma(y) and yield strain epsilon(y)-were investigated through a multiple linear regression analysis. H/D ratio and porosity exhibited strong influence on the mechanical behavior, resulting in variations in mean E-app of 60% and 95%, respectively. sigma(y) was comparatively less sensitive to H/D ratio over the range investigated in this study, with 15% variation in mean values. In contrast, porosity resulted in almost 100% variation in mean sigma(y) values. Pore size was not a significant factor for mechanical behavior, although it is a critical factor in the biological behavior of the scaffolds. Quantifying the influence of porosity, H/D ratio and pore size on bench-top tested bulk mechanical properties can help optimize the development of bone scaffolds from a biomechanical perspective.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 2073-4360 ISBN Medium  
  Area Expedition Conference  
  Notes WOS:000887647600001 Approved  
  Call Number UAI @ alexi.delcanto @ Serial 1655  
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