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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 Pavissich, J.P.; Vargas, I.T.; Gonzalez, B.; Pasten, P.A.; Pizarro, G.E. pdf  doi
openurl 
  Title Culture dependent and independent analyses of bacterial communities involved in copper plumbing corrosion Type
  Year 2010 Publication Journal Of Applied Microbiology Abbreviated Journal J. Appl. Microbiol.  
  Volume 109 Issue 3 Pages 771-782  
  Keywords bacterial community; biofilm; copper plumbing; microbially influenced corrosion; water quality  
  Abstract Aims: This study used culture-dependent and culture-independent approaches to characterize bacterial communities in copper plumbing corrosion and to assess biofilm formation and copper resistance of heterotrophic bacteria isolated from copper pipes. Methods and Results: Water and copper pipes were collected from a cold-water household distribution system affected by 'blue water' corrosion and presenting biofilm formation. Corrosion-promoting ageing experiments were performed with conditioned unused copper pipes filled with unfiltered and filtered sampled water as nonsterile and sterile treatments, respectively. During 8 weeks, stagnant water within the pipes was replaced with aerated fresh water every 2 or 3 days. Total copper and pH were determined in sampled water, and copper pipe coupons were cut for microscopic analyses. Biofilms were extracted from field and laboratory pipes, and total DNA was isolated. Bacterial communities' composition was analysed by terminal restriction fragment length polymorphism (T-RFLP) and clonal libraries of 16S rRNA genes. Heterotrophic bacterial isolates were obtained from water and biofilm extracts and characterized in terms of biofilm formation capacity and copper minimum inhibitory concentration. The results indicated that copper concentration in stagnant water from nonsterile treatments was much higher than in sterile treatments and corrosion by-products structure in coupon surfaces was different. Multivariate analysis of T-RFLP profiles and clone sequencing showed significant dissimilarity between field and laboratory biofilm communities, and a low richness and the dominant presence of Gamma- and Betaproteobacteria in both cases. Several bacterial isolates formed biofilm and tolerated high copper concentrations. Conclusions: The study demonstrates microbially influenced corrosion (MIC) in copper plumbing. Gamma- and Betaproteobacteria dominated the corroded copper piping bacterial community, whose ability to form biofilms may be important for bacterial corrosion promotion and survival in MIC events. Significance and Impact of the Study: The characterization of micro-organisms that influence copper plumbing corrosion has significant implications for distribution system management and copper corrosion control.  
  Address [Pavissich, J. P.; Vargas, I. T.; Pasten, P. A.; Pizarro, G. E.] Pontificia Univ Catolica Chile, Dept Ingn Hidraul & Ambiental, Escuela Ingn, Santiago 6904411, Chile, Email: gpizarro@ing.puc.cl  
  Corporate Author Thesis  
  Publisher Wiley-Blackwell Publishing, Inc Place of Publication Editor  
  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 1364-5072 ISBN Medium  
  Area Expedition Conference  
  Notes WOS:000280979700004 Approved  
  Call Number UAI @ eduardo.moreno @ Serial 93  
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Author Slane, J.A.; Vivanco, J.F.; Rose, W.E.; Squire, M.W.; Ploeg, H.L. pdf  doi
openurl 
  Title The influence of low concentrations of a water soluble poragen on the material properties, antibiotic release, and biofilm inhibition of an acrylic bone cement Type
  Year 2014 Publication Materials Science & Engineering C-Materials For Biological Applications Abbreviated Journal Mater. Sci. Eng. C-Mater. Biol. Appl.  
  Volume 42 Issue Pages 168-176  
  Keywords Bone cement; Infection; Drug release; Mechanical properties; Biofilm  
  Abstract Soluble particulate fillers can be incorporated into antibiotic-loaded acrylic bone cement in an effort to enhance antibiotic elution. Xylitol is a material that shows potential for use as a filler due to its high solubility and potential to inhibit biofilm formation. The objective of this work, therefore, was to investigate the usage of low concentrations of xylitol in a gentamicin-loaded cement. Five different cements were prepared with various xylitol loadings (0, 1, 2.5, 5 or 10 g) per cement unit, and the resulting impact on the mechanical properties, cumulative antibiotic release, biofilm inhibition, and thermal characteristics were quantified. Xylitol significantly increased cement porosity and a sustained increase in gentamicin elution was observed in all samples containing xylitol with a maximum cumulative release of 41.3%. Xylitol had no significant inhibitory effect on biofilm formation. All measured mechanical properties tended to decrease with increasing xylitol concentration; however, these effects were not always significant. Polymerization characteristics were consistent among all groups with no significant differences found. The results from this study indicate that xylitol-modified bone cement may not be appropriate for implant fixation but could be used in instances where sustained, increased antibiotic elution is warranted, such as in cement spacers or beads. (C) 2014 Elsevier B.V. All rights reserved.  
  Address [Slane, Josh A.; Ploeg, Heidi-Lynn] Univ Wisconsin, Mat Sci Program, Madison, WI 53706 USA, Email: jaslane@wisc.edu  
  Corporate Author Thesis  
  Publisher Elsevier Science Bv Place of Publication Editor  
  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0928-4931 ISBN Medium  
  Area Expedition Conference  
  Notes WOS:000340687400024 Approved  
  Call Number UAI @ eduardo.moreno @ Serial 403  
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Author Tierra, G.; Pavissich, J.P.; Nerenberg, R.; Xu, Z.L.; Alber, M.S. pdf  doi
openurl 
  Title Multicomponent model of deformation and detachment of a biofilm under fluid flow Type
  Year 2015 Publication Journal of the Royal Society Interface Abbreviated Journal J. R. Soc. Interface  
  Volume 12 Issue 106 Pages 13 pp  
  Keywords biofilm; viscoelasticity; detachment; phase-field model; energetic variation; continuum mechanics  
  Abstract A novel biofilm model is described which systemically couples bacteria, extracellular polymeric substances (EPS) and solvent phases in biofilm. This enables the study of contributions of rheology of individual phases to deformation of biofilm in response to fluid flow as well as interactions between different phases. The model, which is based on first and second laws of thermodynamics, is derived using an energetic variational approach and phase-field method. Phase-field coupling is used to model structural changes of a biofilm. A newly developed unconditionally energy-stable numerical splitting scheme is implemented for computing the numerical solution of the model efficiently. Model simulations predict biofilm cohesive failure for the flow velocity between O(10(-3)) and O(10(-2))ms(-1) which is consistent with experiments. Simulations predict biofilm deformation resulting in the formation of streamers for EPS exhibiting a viscous-dominated mechanical response and the viscosity of EPS being less than O(10) kgm(-1) s(-1). Higher EPS viscosity provides biofilm with greater resistance to deformation and to removal by the flow. Moreover, simulations show that higher EPS elasticity yields the formation of streamers with complex geometries that are more prone to detachment. These model predictions are shown to be in qualitative agreement with experimental observations.  
  Address [Tierra, Giordano] Charles Univ Prague, Fac Math & Phys, Math Inst, Prague 18675 8, Czech Republic, Email: malber@nd.edu  
  Corporate Author Thesis  
  Publisher Royal Soc Place of Publication Editor  
  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 1742-5689 ISBN Medium  
  Area Expedition Conference  
  Notes WOS:000353359900017 Approved  
  Call Number UAI @ eduardo.moreno @ Serial 484  
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