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Full-Text Articles in Engineering
Dynamic Flux Balance Modeling Of Microbial Co-Cultures For Efficient Batch Fermentation Of Glucose And Xylose Mixtures, Timothy J. Hanly, Michael A. Henson
Dynamic Flux Balance Modeling Of Microbial Co-Cultures For Efficient Batch Fermentation Of Glucose And Xylose Mixtures, Timothy J. Hanly, Michael A. Henson
Michael A Henson
Sequential uptake of pentose and hexose sugars that compose lignocellulosic biomass limits the ability of pure microbial cultures to efficiently produce value-added bioproducts. In this work, we used dynamic flux balance modeling to examine the capability of mixed cultures of substrate-selective microbes to improve the utilization of glucose/xylose mixtures and to convert these mixed substrates into products. Co-culture simulations of Escherichia coli strains ALS1008 and ZSC113, engineered for glucose and xylose only uptake respectively, indicated that improvements in batch substrate consumption observed in previous experimental studies resulted primarily from an increase in ZSC113 xylose uptake relative to wild-type E. coli. …
Mechanistic Modelling Of Dynamic Mri Data Predicts That Tumour Heterogeneity Decreases Therapeutic Response, R Venkatasubramanian, Rb Arenas, Michael A. Henson, Ns Forbes
Mechanistic Modelling Of Dynamic Mri Data Predicts That Tumour Heterogeneity Decreases Therapeutic Response, R Venkatasubramanian, Rb Arenas, Michael A. Henson, Ns Forbes
Michael A Henson
BACKGROUND: Dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) contains crucial information about tumour heterogeneity and the transport limitations that reduce drug efficacy. Mathematical modelling of drug delivery and cellular responsiveness based on underutilised DCE-MRI data has the unique potential to predict therapeutic responsiveness for individual patients. METHODS: To interpret DCE-MRI data, we created a modelling framework that operates over multiple time and length scales and incorporates intracellular metabolism, nutrient and drug diffusion, trans-vascular permeability, and angiogenesis. The computational methodology was used to analyse DCE-MR images collected from eight breast cancer patients at Baystate Medical Center in Springfield, MA. RESULTS: Computer simulations …
Characterization Of Aggregate Size In Taxus Suspension Cell Culture, Martin E. Kolewe, Michael A. Henson, Susan C. Roberts
Characterization Of Aggregate Size In Taxus Suspension Cell Culture, Martin E. Kolewe, Michael A. Henson, Susan C. Roberts
Michael A Henson
Plant cells grow as aggregates in suspension culture, but little is known about the dynamics of aggregation, and no routine methodology exists to measure aggregate size. In this study, we evaluate several different methods to characterize aggregate size in Taxus suspension cultures, in which aggregate diameters range from 50 μm to 2000 μm, including filtration and image analysis, and develop a novel method using a specially equipped Coulter counter system. We demonstrate the suitability of this technology to measure plant cell culture aggregates, and show that it can be reliably used to measure total biomass accumulation compared to standard methods …
A Multiscale Model To Investigate Circadian Rhythmicity Of Pacemaker Neurons In The Suprachiasmatic Nucleus, Christina Vasalou, Michael A. Henson
A Multiscale Model To Investigate Circadian Rhythmicity Of Pacemaker Neurons In The Suprachiasmatic Nucleus, Christina Vasalou, Michael A. Henson
Michael A Henson
The suprachiasmatic nucleus (SCN) of the hypothalamus is a multicellular system that drives daily rhythms in mammalian behavior and physiology. Although the gene regulatory network that produces daily oscillations within individual neurons is well characterized, less is known about the electrophysiology of the SCN cells and how firing rate correlates with circadian gene expression. We developed a firing rate code model to incorporate known electrophysiological properties of SCN pacemaker cells, including circadian dependent changes in membrane voltage and ion conductances. Calcium dynamics were included in the model as the putative link between electrical firing and gene expression. Individual ion currents …