The Experts below are selected from a list of 312 Experts worldwide ranked by ideXlab platform
Marva Angela Blankson - One of the best experts on this subject based on the ideXlab platform.
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physico mechanical microstructural and dynamic properties of newly developed artificial fly ash based lightweight aggregate rubber concrete composite
Composites Part B-engineering, 2015Co-Authors: Pejman Keikhaei Dehdezi, Savas Erdem, Marva Angela BlanksonAbstract:Abstract The use of industrial by-products in concrete would increase the sustainability of the construction industry. In this study, the potential use of scrap crumb rubber as fine aggregate in lightweight (Lytag) concrete was experimentally investigated. The effects of replacing natural sand by crumb rubber particles on the physico-mechanical, micro-structural and dynamic properties of the Lytag concrete were evaluated. When the rubber was introduced, the reduction in compressive strength of the Lytag concrete was experienced due to the less than perfect bond between the cement paste and the rubber as confirmed by the micro-structural observation. Additionally, there was flocculation of some of the crumb rubber particles and the packing of the rubber particles contributed to pockets of voids resulted in anisotropy in the concrete. The results also showed that the rubber not only meliorated the resistance of the cementitious Lytag composite to cracking from impact load but overall impact strength was also improved as the rubber particles acted as impedance to crack initiation and propagation.
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Physico-mechanical, microstructural and dynamic properties of newly developed artificial fly ash based lightweight aggregate – Rubber concrete composite
Composites Part B: Engineering, 2015Co-Authors: Pejman Keikhaei Dehdezi, Savas Erdem, Marva Angela BlanksonAbstract:Abstract The use of industrial by-products in concrete would increase the sustainability of the construction industry. In this study, the potential use of scrap crumb rubber as fine aggregate in lightweight (Lytag) concrete was experimentally investigated. The effects of replacing natural sand by crumb rubber particles on the physico-mechanical, micro-structural and dynamic properties of the Lytag concrete were evaluated. When the rubber was introduced, the reduction in compressive strength of the Lytag concrete was experienced due to the less than perfect bond between the cement paste and the rubber as confirmed by the micro-structural observation. Additionally, there was flocculation of some of the crumb rubber particles and the packing of the rubber particles contributed to pockets of voids resulted in anisotropy in the concrete. The results also showed that the rubber not only meliorated the resistance of the cementitious Lytag composite to cracking from impact load but overall impact strength was also improved as the rubber particles acted as impedance to crack initiation and propagation.
Ana M. Azevedo - One of the best experts on this subject based on the ideXlab platform.
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Lytag driven purification strategies for monoclonal antibodies using quaternary amine ligands as affinity matrices
Journal of Chemical Technology & Biotechnology, 2018Co-Authors: Isabel Campospinto, Emanuel V. Capela, Miguel Arévalo Rodríguez, Poondi Rajesh Gavara, Rita A Silvasantos, Marcelo Fernandezlahore, Raquel M Airesbarros, Ana M. AzevedoAbstract:BACKGROUND: Monoclonal antibodies are becoming a leading class of biopharmaceuticals but to increase their accessibility by the general population, new production processes must be developed in particular for the downstream processing. RESULTS: In this work, an alternative and innovative affinity chromatographic method using quaternary amine matrices is proposed. Separation is driven by the dual affinity ligand Lytag‐Z, composed of a choline binding polypeptide (Lytag) and the synthetic antibody binding Z domain. A two‐elution method was developed for the purification of mAbs and the performance of different anion exchangers containing quaternary amines that act as choline analogues – CIMmultus Q, Q Sepharose and gPore Q – were tested and compared, with both CIMmultus Q and Q Sepharose allowing a recovery of more than 94% of mAbs from a CHO cell supernatant with a purity greater than 95%. An integrated platform combining an initial affinity extraction step for the clarification and capture of mAbs and a subsequent chromatographic separation using Q‐matrices for the polishing of mAbs is also proposed. Lytag‐Z triggers the extraction of 94.7 ± 1.7% mAbs to the PEG‐rich phase, as opposed to 26.9 ± 0.6% in the absence of the ligand, using 7% PEG 3350 and 6% dextran 500 k. Further purification using Q Sepharose allowed a mAb recovery of 95.3 ± 1.4% with a purity level of 91.4 ± 13.0%. CONCLUSION: An integrated platform based on two purification steps – affinity extraction and affinity chromatography – results in an overall process yield of 90%, allowing the processing of mAbs directly from a non‐clarified CHO cell culture. © 2017 Society of Chemical Industry
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Lytag‐driven purification strategies for monoclonal antibodies using quaternary amine ligands as affinity matrices
Journal of Chemical Technology & Biotechnology, 2017Co-Authors: Isabel Campos-pinto, M. Raquel Aires-barros, Emanuel V. Capela, A. Rita Silva-santos, Miguel Arévalo Rodríguez, Poondi Rajesh Gavara, Marcelo Fernandez-lahore, Ana M. AzevedoAbstract:BACKGROUND: Monoclonal antibodies are becoming a leading class of biopharmaceuticals but to increase their accessibility by the general population, new production processes must be developed in particular for the downstream processing. RESULTS: In this work, an alternative and innovative affinity chromatographic method using quaternary amine matrices is proposed. Separation is driven by the dual affinity ligand Lytag‐Z, composed of a choline binding polypeptide (Lytag) and the synthetic antibody binding Z domain. A two‐elution method was developed for the purification of mAbs and the performance of different anion exchangers containing quaternary amines that act as choline analogues – CIMmultus Q, Q Sepharose and gPore Q – were tested and compared, with both CIMmultus Q and Q Sepharose allowing a recovery of more than 94% of mAbs from a CHO cell supernatant with a purity greater than 95%. An integrated platform combining an initial affinity extraction step for the clarification and capture of mAbs and a subsequent chromatographic separation using Q‐matrices for the polishing of mAbs is also proposed. Lytag‐Z triggers the extraction of 94.7 ± 1.7% mAbs to the PEG‐rich phase, as opposed to 26.9 ± 0.6% in the absence of the ligand, using 7% PEG 3350 and 6% dextran 500 k. Further purification using Q Sepharose allowed a mAb recovery of 95.3 ± 1.4% with a purity level of 91.4 ± 13.0%. CONCLUSION: An integrated platform based on two purification steps – affinity extraction and affinity chromatography – results in an overall process yield of 90%, allowing the processing of mAbs directly from a non‐clarified CHO cell culture. © 2017 Society of Chemical Industry
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A multiplexed microfluidic toolbox for the rapid optimization of affinity-driven partition in aqueous two phase systems.
Journal of chromatography. A, 2017Co-Authors: Eduardo J. S. Brás, Miguel Arévalo-rodríguez, Ana M. Azevedo, Ruben R.g. Soares, Pedro Fernandes, Virginia Chu, João Pedro Conde, M. Raquel Aires-barrosAbstract:Antibodies and other protein products such as interferons and cytokines are biopharmaceuticals of critical importance which, in order to be safely administered, have to be thoroughly purified in a cost effective and efficient manner. The use of aqueous two-phase extraction (ATPE) is a viable option for this purification, but these systems are difficult to model and optimization procedures require lengthy and expensive screening processes. Here, a methodology for the rapid screening of antibody extraction conditions using a microfluidic channel-based toolbox is presented. A first microfluidic structure allows a simple negative-pressure driven rapid screening of up to 8 extraction conditions simultaneously, using less than 20μL of each phase-forming solution per experiment, while a second microfluidic structure allows the integration of multi-step extraction protocols based on the results obtained with the first device. In this paper, this microfluidic toolbox was used to demonstrate the potential of Lytag fusion proteins used as affinity tags to optimize the partitioning of antibodies in ATPE processes, where a maximum partition coefficient (K) of 9.2 in a PEG 3350/phosphate system was obtained for the antibody extraction in the presence of the Lytag-Z dual ligand. This represents an increase of approx. 3.7 fold when compared with the same conditions without the affinity molecule (K=2.5). Overall, this miniaturized and versatile approach allowed the rapid optimization of molecule partition followed by a proof-of-concept demonstration of an integrated back extraction procedure, both of which are critical procedures towards obtaining high purity biopharmaceuticals using ATPE.
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Integration of cell harvest with affinity-enhanced purification of monoclonal antibodies using aqueous two-phase systems with a dual tag ligand
Separation and Purification Technology, 2017Co-Authors: Isabel Campos-pinto, Miguel Arévalo-rodríguez, Sara A.s.l. Rosa, M. Raquel Aires-barros, Edith Espitia-saloma, Marco Rito-palomares, Oscar Aguilar, Ana M. AzevedoAbstract:Monoclonal antibodies (mAbs) are currently the most important class of recombinant protein therapeutics in the biotechnological and biopharmaceutical industry with more than 250 therapeutic mAbs currently undergoing clinical trials. High titer producing cultures and complex mixtures containing high cell densities, together with an increasing growing demand for highly pure mAbs is making recovery and purification processes hot targets for improvement and opens important technological challenges in mAbs manufacturing platforms. This work explores the use of an affinity dual ligand based on a choline binding polypeptide tag (C-LytA) fused to the synthetic antibody binding Z domain (Lytag-Z) in aqueous two-phase systems (ATPS) composed of phase forming polymers able to bind to the choline binding site of C-LytA (polyethylene glycol -PEG- and thermosensitive polymers -EOPO) for mAbs selective extraction. Integration of harvesting and ATPS affinity extraction steps were evaluated with ATPS proving to be an alternative strategy for integrating the clarification and the primary recovery of mAbs. An extraction yield of 89% and a clarification higher than 95% were achieved using a system composed of 7% PEG 3350 and 6% dextran 500,000.
Pejman Keikhaei Dehdezi - One of the best experts on this subject based on the ideXlab platform.
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physico mechanical microstructural and dynamic properties of newly developed artificial fly ash based lightweight aggregate rubber concrete composite
Composites Part B-engineering, 2015Co-Authors: Pejman Keikhaei Dehdezi, Savas Erdem, Marva Angela BlanksonAbstract:Abstract The use of industrial by-products in concrete would increase the sustainability of the construction industry. In this study, the potential use of scrap crumb rubber as fine aggregate in lightweight (Lytag) concrete was experimentally investigated. The effects of replacing natural sand by crumb rubber particles on the physico-mechanical, micro-structural and dynamic properties of the Lytag concrete were evaluated. When the rubber was introduced, the reduction in compressive strength of the Lytag concrete was experienced due to the less than perfect bond between the cement paste and the rubber as confirmed by the micro-structural observation. Additionally, there was flocculation of some of the crumb rubber particles and the packing of the rubber particles contributed to pockets of voids resulted in anisotropy in the concrete. The results also showed that the rubber not only meliorated the resistance of the cementitious Lytag composite to cracking from impact load but overall impact strength was also improved as the rubber particles acted as impedance to crack initiation and propagation.
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Physico-mechanical, microstructural and dynamic properties of newly developed artificial fly ash based lightweight aggregate – Rubber concrete composite
Composites Part B: Engineering, 2015Co-Authors: Pejman Keikhaei Dehdezi, Savas Erdem, Marva Angela BlanksonAbstract:Abstract The use of industrial by-products in concrete would increase the sustainability of the construction industry. In this study, the potential use of scrap crumb rubber as fine aggregate in lightweight (Lytag) concrete was experimentally investigated. The effects of replacing natural sand by crumb rubber particles on the physico-mechanical, micro-structural and dynamic properties of the Lytag concrete were evaluated. When the rubber was introduced, the reduction in compressive strength of the Lytag concrete was experienced due to the less than perfect bond between the cement paste and the rubber as confirmed by the micro-structural observation. Additionally, there was flocculation of some of the crumb rubber particles and the packing of the rubber particles contributed to pockets of voids resulted in anisotropy in the concrete. The results also showed that the rubber not only meliorated the resistance of the cementitious Lytag composite to cracking from impact load but overall impact strength was also improved as the rubber particles acted as impedance to crack initiation and propagation.
M. Raquel Aires-barros - One of the best experts on this subject based on the ideXlab platform.
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Lytag‐driven purification strategies for monoclonal antibodies using quaternary amine ligands as affinity matrices
Journal of Chemical Technology & Biotechnology, 2017Co-Authors: Isabel Campos-pinto, M. Raquel Aires-barros, Emanuel V. Capela, A. Rita Silva-santos, Miguel Arévalo Rodríguez, Poondi Rajesh Gavara, Marcelo Fernandez-lahore, Ana M. AzevedoAbstract:BACKGROUND: Monoclonal antibodies are becoming a leading class of biopharmaceuticals but to increase their accessibility by the general population, new production processes must be developed in particular for the downstream processing. RESULTS: In this work, an alternative and innovative affinity chromatographic method using quaternary amine matrices is proposed. Separation is driven by the dual affinity ligand Lytag‐Z, composed of a choline binding polypeptide (Lytag) and the synthetic antibody binding Z domain. A two‐elution method was developed for the purification of mAbs and the performance of different anion exchangers containing quaternary amines that act as choline analogues – CIMmultus Q, Q Sepharose and gPore Q – were tested and compared, with both CIMmultus Q and Q Sepharose allowing a recovery of more than 94% of mAbs from a CHO cell supernatant with a purity greater than 95%. An integrated platform combining an initial affinity extraction step for the clarification and capture of mAbs and a subsequent chromatographic separation using Q‐matrices for the polishing of mAbs is also proposed. Lytag‐Z triggers the extraction of 94.7 ± 1.7% mAbs to the PEG‐rich phase, as opposed to 26.9 ± 0.6% in the absence of the ligand, using 7% PEG 3350 and 6% dextran 500 k. Further purification using Q Sepharose allowed a mAb recovery of 95.3 ± 1.4% with a purity level of 91.4 ± 13.0%. CONCLUSION: An integrated platform based on two purification steps – affinity extraction and affinity chromatography – results in an overall process yield of 90%, allowing the processing of mAbs directly from a non‐clarified CHO cell culture. © 2017 Society of Chemical Industry
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A multiplexed microfluidic toolbox for the rapid optimization of affinity-driven partition in aqueous two phase systems.
Journal of chromatography. A, 2017Co-Authors: Eduardo J. S. Brás, Miguel Arévalo-rodríguez, Ana M. Azevedo, Ruben R.g. Soares, Pedro Fernandes, Virginia Chu, João Pedro Conde, M. Raquel Aires-barrosAbstract:Antibodies and other protein products such as interferons and cytokines are biopharmaceuticals of critical importance which, in order to be safely administered, have to be thoroughly purified in a cost effective and efficient manner. The use of aqueous two-phase extraction (ATPE) is a viable option for this purification, but these systems are difficult to model and optimization procedures require lengthy and expensive screening processes. Here, a methodology for the rapid screening of antibody extraction conditions using a microfluidic channel-based toolbox is presented. A first microfluidic structure allows a simple negative-pressure driven rapid screening of up to 8 extraction conditions simultaneously, using less than 20μL of each phase-forming solution per experiment, while a second microfluidic structure allows the integration of multi-step extraction protocols based on the results obtained with the first device. In this paper, this microfluidic toolbox was used to demonstrate the potential of Lytag fusion proteins used as affinity tags to optimize the partitioning of antibodies in ATPE processes, where a maximum partition coefficient (K) of 9.2 in a PEG 3350/phosphate system was obtained for the antibody extraction in the presence of the Lytag-Z dual ligand. This represents an increase of approx. 3.7 fold when compared with the same conditions without the affinity molecule (K=2.5). Overall, this miniaturized and versatile approach allowed the rapid optimization of molecule partition followed by a proof-of-concept demonstration of an integrated back extraction procedure, both of which are critical procedures towards obtaining high purity biopharmaceuticals using ATPE.
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Integration of cell harvest with affinity-enhanced purification of monoclonal antibodies using aqueous two-phase systems with a dual tag ligand
Separation and Purification Technology, 2017Co-Authors: Isabel Campos-pinto, Miguel Arévalo-rodríguez, Sara A.s.l. Rosa, M. Raquel Aires-barros, Edith Espitia-saloma, Marco Rito-palomares, Oscar Aguilar, Ana M. AzevedoAbstract:Monoclonal antibodies (mAbs) are currently the most important class of recombinant protein therapeutics in the biotechnological and biopharmaceutical industry with more than 250 therapeutic mAbs currently undergoing clinical trials. High titer producing cultures and complex mixtures containing high cell densities, together with an increasing growing demand for highly pure mAbs is making recovery and purification processes hot targets for improvement and opens important technological challenges in mAbs manufacturing platforms. This work explores the use of an affinity dual ligand based on a choline binding polypeptide tag (C-LytA) fused to the synthetic antibody binding Z domain (Lytag-Z) in aqueous two-phase systems (ATPS) composed of phase forming polymers able to bind to the choline binding site of C-LytA (polyethylene glycol -PEG- and thermosensitive polymers -EOPO) for mAbs selective extraction. Integration of harvesting and ATPS affinity extraction steps were evaluated with ATPS proving to be an alternative strategy for integrating the clarification and the primary recovery of mAbs. An extraction yield of 89% and a clarification higher than 95% were achieved using a system composed of 7% PEG 3350 and 6% dextran 500,000.
Savas Erdem - One of the best experts on this subject based on the ideXlab platform.
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physico mechanical microstructural and dynamic properties of newly developed artificial fly ash based lightweight aggregate rubber concrete composite
Composites Part B-engineering, 2015Co-Authors: Pejman Keikhaei Dehdezi, Savas Erdem, Marva Angela BlanksonAbstract:Abstract The use of industrial by-products in concrete would increase the sustainability of the construction industry. In this study, the potential use of scrap crumb rubber as fine aggregate in lightweight (Lytag) concrete was experimentally investigated. The effects of replacing natural sand by crumb rubber particles on the physico-mechanical, micro-structural and dynamic properties of the Lytag concrete were evaluated. When the rubber was introduced, the reduction in compressive strength of the Lytag concrete was experienced due to the less than perfect bond between the cement paste and the rubber as confirmed by the micro-structural observation. Additionally, there was flocculation of some of the crumb rubber particles and the packing of the rubber particles contributed to pockets of voids resulted in anisotropy in the concrete. The results also showed that the rubber not only meliorated the resistance of the cementitious Lytag composite to cracking from impact load but overall impact strength was also improved as the rubber particles acted as impedance to crack initiation and propagation.
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Physico-mechanical, microstructural and dynamic properties of newly developed artificial fly ash based lightweight aggregate – Rubber concrete composite
Composites Part B: Engineering, 2015Co-Authors: Pejman Keikhaei Dehdezi, Savas Erdem, Marva Angela BlanksonAbstract:Abstract The use of industrial by-products in concrete would increase the sustainability of the construction industry. In this study, the potential use of scrap crumb rubber as fine aggregate in lightweight (Lytag) concrete was experimentally investigated. The effects of replacing natural sand by crumb rubber particles on the physico-mechanical, micro-structural and dynamic properties of the Lytag concrete were evaluated. When the rubber was introduced, the reduction in compressive strength of the Lytag concrete was experienced due to the less than perfect bond between the cement paste and the rubber as confirmed by the micro-structural observation. Additionally, there was flocculation of some of the crumb rubber particles and the packing of the rubber particles contributed to pockets of voids resulted in anisotropy in the concrete. The results also showed that the rubber not only meliorated the resistance of the cementitious Lytag composite to cracking from impact load but overall impact strength was also improved as the rubber particles acted as impedance to crack initiation and propagation.
