The Experts below are selected from a list of 300 Experts worldwide ranked by ideXlab platform
Bruce Jefferson - One of the best experts on this subject based on the ideXlab platform.
-
hydrophobically associating cationic polymers as micro bubble surface modifiers in dissolved air flotation for cyanobacteria Cell separation
Water Research, 2014Co-Authors: Michael R Whittaker, Mengxue Diao, Volga Bulmus, William L Peirson, Bruce Jefferson, Richard M Stuetz, Anh V. Nguyen, Rita K HendersonAbstract:Dissolved air flotation (DAF), an effective treatment method for clarifying algae/cyanobacteria-laden water, is highly dependent on coagulation-flocculation. Treatment of algae can be problematic due to unpredictable coagulant demand during blooms. To eliminate the need for coagulation-flocculation, the use of commercial polymers or surfactants to alter bubble charge in DAF has shown potential, termed the PosiDAF process. When using surfactants, poor Removal was obtained but good bubble adherence was observed. Conversely, when using polymers, effective Cell Removal was obtained, attributed to polymer bridging, but polymers did not adhere well to the bubble surface, resulting in a cationic clarified effluent that was indicative of high polymer concentrations. In order to combine the attributes of both polymers (bridging ability) and surfactants (hydrophobicity), in this study, a commercially-available cationic polymer, poly(dimethylaminoethyl methacrylate) (polyDMAEMA), was functionalised with hydrophobic pendant groups of various carbon chain lengths to improve adherence of polymer to a bubble surface. Its performance in PosiDAF was contrasted against commercially-available poly(diallyl dimethyl ammonium chloride) (polyDADMAC). All synthesised polymers used for bubble surface modification were found to produce positively charged bubbles. When applying these cationic micro-bubbles in PosiDAF, in the absence of coagulation-flocculation, Cell Removals in excess of 90% were obtained, reaching a maximum of 99% Cell Removal and thus demonstrating process viability. Of the synthesised polymers, the polymer containing the largest hydrophobic functionality resulted in highly anionic treated effluent, suggesting stronger adherence of polymers to bubble surfaces and reduced residual polymer concentrations.
-
Examination of the physical properties of Microcystis aeruginosa flocs produced on coagulation with metal salts
Water research, 2014Co-Authors: A. Gonzalez-torres, Richard M Stuetz, Bruce Jefferson, J. Putnam, Rita K HendersonAbstract:Abstract Coagulation–flocculation (C–F) is a key barrier to cyanobacterial and algal Cell infiltration in water treatment plants during seasonal blooms. However, the resultant Cell floc properties, in terms of size, strength and density, which dominate under different coagulation conditions and govern Cell Removal, are not well understood. This paper investigated the floc properties produced during C–F of the cyanobacterium, Microcystis aeruginosa, under low and high doses of aluminium sulphate and ferric chloride coagulants and at different pH values, so as to promote charge neutralisation (CN) and sweep flocculation (SF) dominant conditions (or a combination of these). It was demonstrated that application of ferric chloride produced larger flocs that resulted in higher Cell Removal during jar testing. These flocs were also larger than those observed for natural organic matter (NOM) and kaolin, suggesting a role of algogenic organic matter (AOM) as an inherent bioflocculant. Under SF conditions, stronger flocs were produced; however, these had lower capacity for size recovery after exposure to high shear. Analysis of particle size distribution demonstrated that large scale fragmentation followed by erosion dominated for CN while erosion dominated under SF conditions. Overall, marked differences were observed dependent on the coagulation regime imposed that have implications for improving robustness of Cell Removal by downstream separation processes. While the cyanobacterium, M. aeruginosa, appeared to share general floc characteristics commonly observed for NOM and kaolin flocs, there were distinct differences in terms of size and strength, which may be attributed to AOM.
-
the influence of ultrasound frequency and power on the algal species microcystis aeruginosa aphanizomenon flos aquae scenedesmus subspicatus and melosira sp
Environmental Technology, 2013Co-Authors: Diane Purcell, Simon A Parsons, Bruce JeffersonAbstract:We report on the effectiveness of sonication on controlling the growth of four problematic algal species which are morphologically different and from three algal divisions. Two cyanobacterial species Microcystis aeruginosa (uniCellular) and Aphanizomenon flos-aquae (filamentous), one green alga Scenedesmus subspicatus (colonial) and lastly a diatom species Melosira sp. (filamentous) were subjected to ultrasound of selected low to high frequencies ranging from 20 to 1144 kHz. Microcystis aeruginosa and Scenedesmus subspicatus highest Cell Removal rates were 16±2% and 20±3% when treated with the same ultrasound frequency of 862 kHz but differing energy levels of 133 and 67 kWh m−3, respectively. Aphanizomenon flos-aquae best Removal rate was 99±1% after 862 kHz and 133 kWh m−3 of energy, with Melosira sp. achieving its highest Cell Removal at 83% subsequent to ultrasound of 20 kHz and 19 kWh m−3. Microcystis aeruginosa and Scenedesmus subspicatus are considered non-susceptible species to ultrasound treatmen...
-
The influence of ultrasound frequency and power, on the algal species Microcystis aeruginosa, Aphanizomenon flos-aquae, Scenedesmus subspicatus and Melosira sp.
Environmental technology, 2013Co-Authors: Diane Purcell, Simon A Parsons, Bruce JeffersonAbstract:We report on the effectiveness of sonication on controlling the growth of four problematic algal species which are morphologically different and from three algal divisions. Two cyanobacterial species Microcystis aeruginosa (uniCellular) and Aphanizomenon flos-aquae (filamentous), one green alga Scenedesmus subspicatus (colonial) and lastly a diatom species Melosira sp. (filamentous) were subjected to ultrasound of selected low to high frequencies ranging from 20 to 1144 kHz. Microcystis aeruginosa and Scenedesmus subspicatus highest Cell Removal rates were 16 +/- 2% and 20 +/- 3% when treated with the same ultrasound frequency of 862 kHz but differing energy levels of 133 and 67 kWh m(-3), respectively. Aphanizomenon flos-aquae best Removal rate was 99 +/- 1% after 862 kHz and 133 kWh m(-3) of energy, with Melosira sp. achieving its highest Cell Removal at 83% subsequent to ultrasound of 20 kHz and 19 kWh m(-3). Microcystis aeruginosa and Scenedesmus subspicatus are considered non-susceptible species to ultrasound treatment from a water treatment perspective due to their low Cell Removal rates; however, photosynthetic activity reduction of 65% for Microcystis aeruginosa does indicate the possible utilization of ultrasound to control bloom growth, rather than bloom elimination. Conversely, Aphanizomenon flos-aquae and Melosira sp. are deemed species highly susceptible to ultrasound. Morphological differences in shape (filamentous/non-filamentous) and Cell wall structure (silica/peptidoglycan), and presence of gas vacuoles are probable reasons for these differing levels of susceptibility to ultrasound.
Gino Gerosa - One of the best experts on this subject based on the ideXlab platform.
-
first quantitative assay of alpha gal in soft tissues presence and distribution of the epitope before and after Cell Removal from xenogeneic heart valves
Acta Biomaterialia, 2011Co-Authors: Filippo Naso, Alessandro Gandaglia, Laura Iop, Michele Spina, Gino GerosaAbstract:DeCellularized xenograft heart valves might be the ideal scaffolds for tissue engineered heart valves as the alternative to the currently used biological and mechanical prostheses. However, Removal of the alpha-Gal epitope is a prerequisite to avoid hyperacute rejection of untreated xenograft material. The aim of this study was to develop an ELISA soft-tissue assay for alpha-Gal quantification in xenograft heart valves before and after a detergent-based (TriCol) or equivalent Cell Removal procedure. Leaflets from porcine valves were enzymatically digested to expose the epitope and reacted with the alpha-Gal monoclonal antibody M86 for its recognition. Rabbit erythrocytes were used as a reference for the quantification of alpha-Gal. Native aortic and pulmonary leaflets exhibited different epitope concentration: 4.33×10(11) vs. 7.12×10(11)/10 mg wet tissue (p<0.0001). Sampling of selected zones in native valves revealed a different alpha-Gal distribution within and among different leaflets. The pattern was consistent with immunofluorescence analysis and was unrelated to microvessel density distribution. After TriCol treatment alpha-Gal was no longer detectable in both pulmonary and aortic deCellularized valves, confirming the ability of this method to remove both Cells and alpha-Gal antigen. These results hold promise for a reliable quantitative evaluation of alpha-Gal in deCellularized valves obtained from xenograft material for tissues engineering purposes. Additionally, this method is applicable to further evaluate currently used xenograft bioprostheses.
-
First quantitative assay of alpha-Gal in soft tissues: presence and distribution of the epitope before and after Cell Removal from xenogeneic heart valves.
Acta biomaterialia, 2010Co-Authors: Filippo Naso, Alessandro Gandaglia, Laura Iop, Michele Spina, Gino GerosaAbstract:DeCellularized xenograft heart valves might be the ideal scaffolds for tissue engineered heart valves as the alternative to the currently used biological and mechanical prostheses. However, Removal of the alpha-Gal epitope is a prerequisite to avoid hyperacute rejection of untreated xenograft material. The aim of this study was to develop an ELISA soft-tissue assay for alpha-Gal quantification in xenograft heart valves before and after a detergent-based (TriCol) or equivalent Cell Removal procedure. Leaflets from porcine valves were enzymatically digested to expose the epitope and reacted with the alpha-Gal monoclonal antibody M86 for its recognition. Rabbit erythrocytes were used as a reference for the quantification of alpha-Gal. Native aortic and pulmonary leaflets exhibited different epitope concentration: 4.33×10(11) vs. 7.12×10(11)/10 mg wet tissue (p
-
Differential distribution of structural components and hydration in aortic and pulmonary heart valve conduits: Impact of detergent-based Cell Removal.
Acta biomaterialia, 2010Co-Authors: Filippo Naso, Alessandro Gandaglia, Marilena Formato, Antonio Cigliano, Antonio Junior Lepedda, Gino Gerosa, Michel SpinaAbstract:Evaluation of the physiological performance of biological scaffolds for tissue engineering applications has been mostly based on biophysical and morphological methods, with limited attention paid to the quantitative contribution of the main structural components to native and/or treated valve assemblies. In the present study quantitation addressed the porcine leaflet, sinus and adjacent wall of aortic and pulmonary valved conduits before and after detergent-based Cell Removal. Collagen, elastin, glycosaminoglycan, lipid and water contents were expressed in terms of relative concentration and volume fraction in order to assess their effective contribution to the native tissue and to changes following deCellularization procedures. The main findings were recognition of unexpectedly large water and underestimated collagen contents, differential distribution of elastin between the sectors and of glycosaminoglycan along the conduits and pulmonary scaffold destabilization upon Cell Removal, not found in the aortic case. Simultaneous investigations allowed consistent comparisons between native and deCellularized tissues and added analytical knowledge crucial for designing realistic constitutive models. We have provided a quantitative structural foundation for earlier biomechanical findings in pulmonary leaflets and the basis for validation of theoretical assumptions still lacking the support of experimental evidence in both conduits. Future insights into the distribution of load-bearing components in human conduits are likely to provide indications important to optimize the surgical positioning of valvular grafts.
Filippo Naso - One of the best experts on this subject based on the ideXlab platform.
-
first quantitative assay of alpha gal in soft tissues presence and distribution of the epitope before and after Cell Removal from xenogeneic heart valves
Acta Biomaterialia, 2011Co-Authors: Filippo Naso, Alessandro Gandaglia, Laura Iop, Michele Spina, Gino GerosaAbstract:DeCellularized xenograft heart valves might be the ideal scaffolds for tissue engineered heart valves as the alternative to the currently used biological and mechanical prostheses. However, Removal of the alpha-Gal epitope is a prerequisite to avoid hyperacute rejection of untreated xenograft material. The aim of this study was to develop an ELISA soft-tissue assay for alpha-Gal quantification in xenograft heart valves before and after a detergent-based (TriCol) or equivalent Cell Removal procedure. Leaflets from porcine valves were enzymatically digested to expose the epitope and reacted with the alpha-Gal monoclonal antibody M86 for its recognition. Rabbit erythrocytes were used as a reference for the quantification of alpha-Gal. Native aortic and pulmonary leaflets exhibited different epitope concentration: 4.33×10(11) vs. 7.12×10(11)/10 mg wet tissue (p<0.0001). Sampling of selected zones in native valves revealed a different alpha-Gal distribution within and among different leaflets. The pattern was consistent with immunofluorescence analysis and was unrelated to microvessel density distribution. After TriCol treatment alpha-Gal was no longer detectable in both pulmonary and aortic deCellularized valves, confirming the ability of this method to remove both Cells and alpha-Gal antigen. These results hold promise for a reliable quantitative evaluation of alpha-Gal in deCellularized valves obtained from xenograft material for tissues engineering purposes. Additionally, this method is applicable to further evaluate currently used xenograft bioprostheses.
-
First quantitative assay of alpha-Gal in soft tissues: presence and distribution of the epitope before and after Cell Removal from xenogeneic heart valves.
Acta biomaterialia, 2010Co-Authors: Filippo Naso, Alessandro Gandaglia, Laura Iop, Michele Spina, Gino GerosaAbstract:DeCellularized xenograft heart valves might be the ideal scaffolds for tissue engineered heart valves as the alternative to the currently used biological and mechanical prostheses. However, Removal of the alpha-Gal epitope is a prerequisite to avoid hyperacute rejection of untreated xenograft material. The aim of this study was to develop an ELISA soft-tissue assay for alpha-Gal quantification in xenograft heart valves before and after a detergent-based (TriCol) or equivalent Cell Removal procedure. Leaflets from porcine valves were enzymatically digested to expose the epitope and reacted with the alpha-Gal monoclonal antibody M86 for its recognition. Rabbit erythrocytes were used as a reference for the quantification of alpha-Gal. Native aortic and pulmonary leaflets exhibited different epitope concentration: 4.33×10(11) vs. 7.12×10(11)/10 mg wet tissue (p
-
Differential distribution of structural components and hydration in aortic and pulmonary heart valve conduits: Impact of detergent-based Cell Removal.
Acta biomaterialia, 2010Co-Authors: Filippo Naso, Alessandro Gandaglia, Marilena Formato, Antonio Cigliano, Antonio Junior Lepedda, Gino Gerosa, Michel SpinaAbstract:Evaluation of the physiological performance of biological scaffolds for tissue engineering applications has been mostly based on biophysical and morphological methods, with limited attention paid to the quantitative contribution of the main structural components to native and/or treated valve assemblies. In the present study quantitation addressed the porcine leaflet, sinus and adjacent wall of aortic and pulmonary valved conduits before and after detergent-based Cell Removal. Collagen, elastin, glycosaminoglycan, lipid and water contents were expressed in terms of relative concentration and volume fraction in order to assess their effective contribution to the native tissue and to changes following deCellularization procedures. The main findings were recognition of unexpectedly large water and underestimated collagen contents, differential distribution of elastin between the sectors and of glycosaminoglycan along the conduits and pulmonary scaffold destabilization upon Cell Removal, not found in the aortic case. Simultaneous investigations allowed consistent comparisons between native and deCellularized tissues and added analytical knowledge crucial for designing realistic constitutive models. We have provided a quantitative structural foundation for earlier biomechanical findings in pulmonary leaflets and the basis for validation of theoretical assumptions still lacking the support of experimental evidence in both conduits. Future insights into the distribution of load-bearing components in human conduits are likely to provide indications important to optimize the surgical positioning of valvular grafts.
Peter M. Henson - One of the best experts on this subject based on the ideXlab platform.
-
Cell Removal: Efferocytosis
Annual review of cell and developmental biology, 2017Co-Authors: Peter M. HensonAbstract:In metazoans, Removal of Cells in situ is involved in larval maturation, metamorphosis, and embryonic development. In adults, such Cell Removal plays a role in the homeostatic maintenance of Cell numbers and tissue integrity as well as in the response to Cell injury and damage. This Removal involves uptake of the whole or fragmented target Cells into phagocytes. Depending on the organism, these latter may be near-neighbor tissue Cells and/or professional phagocytes such as, in vertebrates, members of the myeloid family of Cells, especially macrophages. The uptake processes appear to involve specialized and highly conserved recognition ligands and receptors, intraCellular signaling in the phagocytes, and mechanisms for ingestion. The recognition of Cells destined for this form of Removal is critical and, significantly, is distinguished for the most part from the recognition of foreign materials and organisms by the innate and adaptive immune systems. In keeping with the key role of Cell Removal in maintaining tissue homeostasis, constant Cell Removal is normally silent, i.e., does not initiate a local tissue reaction. This article discusses these complex and wide-ranging processes in general terms as well as the implications when these processes are disrupted in inflammation, immunity, and disease.
-
burying the dead the impact of failed apoptotic Cell Removal efferocytosis on chronic inflammatory lung disease
Chest, 2006Co-Authors: William R Vandivier, Peter M. Henson, Ivor S DouglasAbstract:Apoptosis and the Removal of apoptotic Cells (termed efferocytosis) are tightly coupled with the regulation of normal lung structure, both in the developing and adult organism. Processes that disrupt or uncouple this balance have the potential to alter normal Cell turnover, ultimately resulting in the induction of lung pathology and disease. Apoptotic Cells are increased in several chronic inflammatory lung diseases, including cystic fibrosis (CF), non-CF bronchiectasis, COPD, and asthma. While this may well be due to the enhanced induction of apoptosis, increasing data suggest that the clearance of dying Cells is also impaired. Because efferocytosis appears to be a key regulatory checkpoint for the innate immune system, the adaptive immune system, and Cell proliferation, the failure of this highly conserved process may contribute to disease pathogenesis by impeding both the resolution of inflammation and the maintenance of alveolar integrity. The recognition of impaired efferocytosis as a contributor to chronic inflammation may ultimately direct us toward the identification of new disease biomarkers, as well as novel therapeutic approaches.
-
Apoptotic Cell Removal in development and tissue homeostasis
Trends in immunology, 2006Co-Authors: Peter M. Henson, David A. HumeAbstract:Cell deletion is a physiological process for the development and maintenance of tissue homeostasis in metazoa. This is mainly achieved by the induction of various forms of programmed Cell death followed by the recognition and Removal of the targeted Cells by phagocytes. In this review, we will discuss Cell deletion in relation to the development and function of the innate immune system, particularly of the mononuclear phagocyte system (MPS), its ontogeny and potential role in tissue remodeling in the embryo and adult. Ongoing studies are addressing the roles of professional phagocytes of the MPS and neighboring tissue Cells in dying Cell Removal, and candidate molecules that might attract mononuclear phagocytes to the dying Cells. The potential phagocyte must discriminate between living and dying Cells; current concepts for this discrimination derive from the observation of newly exposed ligands on the dying Cells and new evidence for direct inhibition of uptake by viable Cells.
-
Apoptotic Cell Removal
Current biology : CB, 2001Co-Authors: Peter M. Henson, Donna L. Bratton, Valerie A. FadokAbstract:Ingestion by professional or amateur phagocytes is the fate of most Cells that undergo apoptosis. Studies in both Caenorhabditis elegans and mammals are now converging to reveal some of the key mechanisms and consequences of this Removal process. At least seven corpse Removal genes in nematodes have mammalian equivalents, and represent elements of signaling pathways involved in uptake. In mammals, a wide variety of apoptotic Cell recognition receptors has been implicated and appears to be divided into two categories, involved in tethering the apoptotic Cell or triggering an uptake mechanism related to macropinocytosis. Apoptotic Cell Removal is normally efficient and non-inflammatory. By contrast, the process may become subverted by parasites to yield a more favorable growth environment, or in other cases lead to fibrosis. Removal may also clinch the apoptotic process itself in Cells not yet completely committed to death.
Alessandro Gandaglia - One of the best experts on this subject based on the ideXlab platform.
-
first quantitative assay of alpha gal in soft tissues presence and distribution of the epitope before and after Cell Removal from xenogeneic heart valves
Acta Biomaterialia, 2011Co-Authors: Filippo Naso, Alessandro Gandaglia, Laura Iop, Michele Spina, Gino GerosaAbstract:DeCellularized xenograft heart valves might be the ideal scaffolds for tissue engineered heart valves as the alternative to the currently used biological and mechanical prostheses. However, Removal of the alpha-Gal epitope is a prerequisite to avoid hyperacute rejection of untreated xenograft material. The aim of this study was to develop an ELISA soft-tissue assay for alpha-Gal quantification in xenograft heart valves before and after a detergent-based (TriCol) or equivalent Cell Removal procedure. Leaflets from porcine valves were enzymatically digested to expose the epitope and reacted with the alpha-Gal monoclonal antibody M86 for its recognition. Rabbit erythrocytes were used as a reference for the quantification of alpha-Gal. Native aortic and pulmonary leaflets exhibited different epitope concentration: 4.33×10(11) vs. 7.12×10(11)/10 mg wet tissue (p<0.0001). Sampling of selected zones in native valves revealed a different alpha-Gal distribution within and among different leaflets. The pattern was consistent with immunofluorescence analysis and was unrelated to microvessel density distribution. After TriCol treatment alpha-Gal was no longer detectable in both pulmonary and aortic deCellularized valves, confirming the ability of this method to remove both Cells and alpha-Gal antigen. These results hold promise for a reliable quantitative evaluation of alpha-Gal in deCellularized valves obtained from xenograft material for tissues engineering purposes. Additionally, this method is applicable to further evaluate currently used xenograft bioprostheses.
-
First quantitative assay of alpha-Gal in soft tissues: presence and distribution of the epitope before and after Cell Removal from xenogeneic heart valves.
Acta biomaterialia, 2010Co-Authors: Filippo Naso, Alessandro Gandaglia, Laura Iop, Michele Spina, Gino GerosaAbstract:DeCellularized xenograft heart valves might be the ideal scaffolds for tissue engineered heart valves as the alternative to the currently used biological and mechanical prostheses. However, Removal of the alpha-Gal epitope is a prerequisite to avoid hyperacute rejection of untreated xenograft material. The aim of this study was to develop an ELISA soft-tissue assay for alpha-Gal quantification in xenograft heart valves before and after a detergent-based (TriCol) or equivalent Cell Removal procedure. Leaflets from porcine valves were enzymatically digested to expose the epitope and reacted with the alpha-Gal monoclonal antibody M86 for its recognition. Rabbit erythrocytes were used as a reference for the quantification of alpha-Gal. Native aortic and pulmonary leaflets exhibited different epitope concentration: 4.33×10(11) vs. 7.12×10(11)/10 mg wet tissue (p
-
Differential distribution of structural components and hydration in aortic and pulmonary heart valve conduits: Impact of detergent-based Cell Removal.
Acta biomaterialia, 2010Co-Authors: Filippo Naso, Alessandro Gandaglia, Marilena Formato, Antonio Cigliano, Antonio Junior Lepedda, Gino Gerosa, Michel SpinaAbstract:Evaluation of the physiological performance of biological scaffolds for tissue engineering applications has been mostly based on biophysical and morphological methods, with limited attention paid to the quantitative contribution of the main structural components to native and/or treated valve assemblies. In the present study quantitation addressed the porcine leaflet, sinus and adjacent wall of aortic and pulmonary valved conduits before and after detergent-based Cell Removal. Collagen, elastin, glycosaminoglycan, lipid and water contents were expressed in terms of relative concentration and volume fraction in order to assess their effective contribution to the native tissue and to changes following deCellularization procedures. The main findings were recognition of unexpectedly large water and underestimated collagen contents, differential distribution of elastin between the sectors and of glycosaminoglycan along the conduits and pulmonary scaffold destabilization upon Cell Removal, not found in the aortic case. Simultaneous investigations allowed consistent comparisons between native and deCellularized tissues and added analytical knowledge crucial for designing realistic constitutive models. We have provided a quantitative structural foundation for earlier biomechanical findings in pulmonary leaflets and the basis for validation of theoretical assumptions still lacking the support of experimental evidence in both conduits. Future insights into the distribution of load-bearing components in human conduits are likely to provide indications important to optimize the surgical positioning of valvular grafts.