Chemical and Biomedical Engineering - Research Publications
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ItemClean Power Technology(Gaodeng Jiaoyu Chubanshe, 2020-12-01)It is timely that Engineering should devote a special issue to the topic of clean energy. The authors of the research articles and the views and comments cover much of what is a very diverse and controversial field. Responses to this topic cover a spectrum ranging from those that argue for emergency action to prevent the extinction of the human race to those that deny the existence of climate change. Before dismissing any group, it is informative for engineers and technologists to note that there is a fairly even distribution across this spectrum
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ItemCODE STROKE ALERT-Concept and Development of a Novel Open-Source Platform to Streamline Acute Stroke Management(FRONTIERS MEDIA SA, 2019-07-31)Introduction: Effective, time-critical intervention in acute stroke is crucial to mitigate mortality rate and morbidity, but delivery of reperfusion treatments is often hampered by pre-, in-, or inter-hospital system level delays. Disjointed, repetitive, and inefficient communication is a consistent contributor to avoidable treatment delay. In the era of rapid reperfusion therapy for ischemic stroke, there is a need for a communication system to synchronize the flow of clinical information across the entire stroke journey. Material/Methods: A multi-disciplinary development team designed an electronic communications platform, integrated between web browsers and a mobile application, to link all relevant members of the stroke treatment pathway. The platform uses tiered notifications, geotagging, incorporates multiple clinical score calculators, and is compliant with security regulations. The system safely saves relevant information for audit and research. Results: Code Stroke Alert is a platform that can be accessed by emergency medical services (EMS) and hospital staff, coordinating the flow of information during acute stroke care, reducing duplication, and error in clinical information handover. Electronic data logs provide an auditable trail of relevant quality improvement metrics, facilitating quality improvement, and research. Discussion: Code Stroke Alert will be freely available to health networks globally. The open-source nature of the software offers valuable potential for future development of plug-ins and add-ons, based on individual institutional needs. Prospective, multi-site implementation, and measurement of clinical impact are underway.
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ItemCFD Simulation of Two-Phase Flow in a Hybrid Pulsed Sieve-Plate Solvent Extraction Column: Prediction of Holdup and Axial-dispersion Coefficients(Taylor & Francis, 2020-01-02)Two-phase computational fluid dynamics (CFD) models for a hybrid pulsed sieve-plate solvent extraction column, as well as a standard pulsed sieve-plate column, have been developed with commercial software ANSYS FLUENT. Hydrodynamic performance including two-phase distribution and velocity fields are generated with the models and comparisons are made between two columns. Important parameters including holdup and axial-dispersion coefficients are studied systematically, and CFD successfully predicts the higher holdup and lower axial-dispersion coefficients for the hybrid pulsed sieve-plate column as measured in the experiments. CFD also gives reasonable predictions for the effect of pulsation intensity, dispersed-phase velocity, and continuous-phase velocity on holdup, except for the effect of pulsation intensity in low pulsation region, and the cause has been discussed from the perspective of droplet breakage and coalescence. Comparison with literature data shows that CFD underestimates the holdup of hybrid pulsed sieve-plate column and standard pulsed sieve-plate column by 23.3% and 31.4%, respectively, and the cause has been discussed from the perspective of drag law. CFD gives good prediction of axial-dispersion coefficients for the hybrid pulsed sieve-plate column and the standard pulsed sieve-plate column with ARD of 12.0% and 14.3%, respectively. This study shows CFD to be a useful tool to predict performance for the novel hybrid pulsed sieve-plate column as well as the standard pulsed sieve-plate column.
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ItemA state-of-the-art review on single drop study in liquid–liquid extraction: Experiments and simulations(Elsevier BV, 2019-12)The experimental and numerical investigations of single drop in liquid/liquid extraction system have been reviewed with particular focus on experimental techniques and computational fluid dynamic simulation approaches. Comprehensive surveys of available experimental techniques and numerical approaches for single drop rising and falling were given. Subsequently, single drop mass transfer was also reviewed both experimentally and numerically. Additionally, single drop breakage and coalescence process and the influencing factors were summarized and compared, so as to establish sub-models for population balance model. Future directions on single drop mass transfer, drop breakage and coalescence were suggested. It is believed that the single drop is a powerful tool to assist extraction process design from lab-scale to pilot-scale.
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ItemAn experimental study on single drop rising in a low interfacial tension liquid–liquid system(Elsevier, 2019-08-01)Terminal velocity of liquid drops is one of the key parameters in liquid–liquid extraction column design. It is important in determining residence time, droplet lifetime, and mass transfer rate. In present paper, the rising behavior of a single drops were investigated in a low interfacial tension system by high speed camera. An n-butanol/water system was used as test system. Correlations for terminal velocity were evaluated and compared, both explicitly and implicitly. Moreover, the influence of salt addition in aqueous phase was also studied, including salt concentrations and types. A Weber–Reynolds correlation was derived on the basis of experimental data. Drag coefficient was then calculated and showed a good agreement compared to the correlations in literatures.
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ItemSurface Modification of Spider Silk Particles to Direct Biomolecular Corona Formation.(American Chemical Society, 2020-05-20)In recent years, spider silk-based materials have attracted attention because of their biocompatibility, processability, and biodegradability. For their potential use in biomaterial applications, i.e., as drug delivery systems and implant coatings for tissue regeneration, it is vital to understand the interactions between the silk biomaterial surface and the biological environment. Like most polymeric carrier systems, spider silk material surfaces can adsorb proteins when in contact with blood, resulting in the formation of a biomolecular corona. Here, we assessed the effect of surface net charge of materials made of recombinant spider silk on the biomolecular corona composition. In-depth proteomic analysis of the biomolecular corona revealed that positively charged spider silk materials surfaces interacted predominantly with fibrinogen-based proteins. This fibrinogen enrichment correlated with blood clotting observed for both positively charged spider silk films and particles. In contrast, negative surface charges prevented blood clotting. Genetic engineering allows the fine-tuning of surface properties of the spider silk particles providing a whole set of recombinant spider silk proteins with different charges or peptide tags to be used for, for example, drug delivery or cell docking, and several of these were analyzed concerning the composition of their biomolecular corona. Taken together this study demonstrates how the surface net charge of recombinant spider silk surfaces affects the composition of the biomolecular corona, which in turn affects macroscopic effects such as fibrin formation and blood clotting.
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ItemModulating the Selectivity and Stealth Properties of Ellipsoidal Polymersomes through a Multivalent Peptide Ligand Display(Wiley, 2020-05-19)There is a need for improved nanomaterials to simultaneously target cancer cells and avoid non‐specific clearance by phagocytes. An ellipsoidal polymersome system is developed with a unique tunable size and shape property. These particles are functionalized with in‐house phage‐display cell‐targeting peptide to target a medulloblastoma cell line in vitro. Particle association with medulloblastoma cells is modulated by tuning the peptide ligand density on the particles. These polymersomes has low levels of association with primary human blood phagocytes. The stealth properties of the polymersomes are further improved by including the peptide targeting moiety, an effect that is likely driven by the peptide protecting the particles from binding blood plasma proteins. Overall, this ellipsoidal polymersome system provides a promising platform to explore tumor cell targeting in vivo.
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ItemHigh-Efficiency Biocatalytic Conversion of Thebaine to Codeine(American Chemical Society, 2020-04-28)An enzymatic biosynthesis approach is described for codeine, the most widely used medicinal opiate, providing a more environmentally sustainable alternative to current chemical conversion, with yields and productivity compatible with industrial production. Escherichia coli strains were engineered to express key enzymes from poppy, including the recently discovered neopinone isomerase, producing codeine from thebaine. We show that compartmentalization of these enzymes in different cells is an effective strategy that allows active spatial and temporal control of reactions, increasing yield and volumetric productivity and reducing byproduct generation. Codeine is produced at a yield of 64% and a volumetric productivity of 0.19 g/(L·h), providing the basis for an industrially applicable aqueous whole-cell biotransformation process. This approach could be used to redirect thebaine-rich feedstocks arising from the U.S. reduction of opioid manufacturing quotas or applied to enable total biosynthesis and may have broader applicability to other medicinal plant compounds.
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ItemOn-chip surface acoustic wave and micropipette aspiration techniques to assess cell elastic properties.(A I P Publishing LLC, 2020-01)The cytoskeletal mechanics and cell mechanical properties play an important role in cellular behaviors. In this study, in order to provide comprehensive insights into the relationship between different cytoskeletal components and cellular elastic moduli, we built a phase-modulated surface acoustic wave microfluidic device to measure cellular compressibility and a microfluidic micropipette-aspiration device to measure cellular Young's modulus. The microfluidic devices were validated based on experimental data and computational simulations. The contributions of structural cytoskeletal actin filament and microtubule to cellular compressibility and Young's modulus were examined in MCF-7 cells. The compressibility of MCF-7 cells was increased after microtubule disruption, whereas actin disruption had no effect. In contrast, Young's modulus of MCF-7 cells was reduced after actin disruption but unaffected by microtubule disruption. The actin filaments and microtubules were stained to confirm the structural alteration in cytoskeleton. Our findings suggest the dissimilarity in the structural roles of actin filaments and microtubules in terms of cellular compressibility and Young's modulus. Based on the differences in location and structure, actin filaments mainly contribute to tensile Young's modulus and microtubules mainly contribute to compressibility. In addition, different responses to cytoskeletal alterations between acoustophoresis and micropipette aspiration demonstrated that micropipette aspiration was better at detecting the change from actin cortex, while the response to acoustophoresis was governed by microtubule networks.
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ItemHeat induced denaturation, aggregation and gelation of almond proteins in skim and full fat almond milk(Elsevier BV, 2020-09-30)The effect of thermal treatment (45-95 ⁰C for 30 minutes) on the structure of almond milk proteins was assessed, as the unfolding and association of these proteins in response to heat is not well understood. Above 55 ⁰C, protein surface hydrophobicity and particle size increased and alpha helical structure decreased, reducing the stability of skim or full fat milk. Fractal protein clusters were observed at 65-75 ⁰C and weakly flocculated gels with a continuous protein network occurred at 85-95 ⁰C, resulting in gels with high water holding capacity and a strength similar to dairy gels. The presence of almond fat increased gel strength but led to a more heterogenous microstructure, which may be improved by homogenisation. Elasticity could also be increased with protein concentration. This study improves our understanding of the heat stability of almond milk proteins and indicates their potential as a gelling ingredient for vegan and vegetarian products.