Open Access. Powered by Scholars. Published by Universities.®
- Keyword
- Publication
- Publication Type
Articles 1 - 11 of 11
Full-Text Articles in Engineering
Genome-Scale Analysis Of Saccharomyces Cerevisiae Metabolism And Ethanol Production In Fed-Batch Culture, Radhakrishnan Mahadevan, Michael A. Henson
Genome-Scale Analysis Of Saccharomyces Cerevisiae Metabolism And Ethanol Production In Fed-Batch Culture, Radhakrishnan Mahadevan, Michael A. Henson
Michael A Henson
A dynamic flux balance model based on a genome-scale metabolic network reconstruction is developed for in silico analysis of Saccharomyces cerevisiae metabolism and ethanol production in fed-batch culture. Metabolic engineering strategies previously identified for their enhanced steady-state biomass and/or ethanol yields are evaluated for fed-batch performance in glucose and glucose/xylose media. Dynamic analysis is shown to provide a single quantitative measure of fed-batch ethanol productivity that explicitly handles the possible tradeoff between the biomass and ethanol yields. Productivity optimization conducted to rank achievable fed-batch performance demonstrates that the genetic manipulation strategy and the fed-batch operating policy should be considered simultaneously. …
A Molecular Model For Intercellular Synchronization In The Mammalian Circadian Clock, Tsz-Leung To, Michael A. Henson, Erik D. Herzog, Francis J. Doyle Iii
A Molecular Model For Intercellular Synchronization In The Mammalian Circadian Clock, Tsz-Leung To, Michael A. Henson, Erik D. Herzog, Francis J. Doyle Iii
Michael A Henson
The mechanisms and consequences of synchrony among heterogeneous oscillators are poorly understood in biological systems. We present a multicellular, molecular model of the mammalian circadian clock that incorporates recent data implicating the neurotransmitter vasoactive intestinal polypeptide (VIP) as the key synchronizing agent. The model postulates that synchrony arises amongcircadian neurons because they release VIP rhythmically on a daily basis and in response to ambient light. Two basic cell types, intrinsically rhythmic pacemakers and damped oscillators, are assumed to arise from a distribution of Period gene transcription rates. Postsynaptic neurons show time-of-day dependent responses to VIP binding through a signaling cascade …
Further Studies Of A Simple Atomistic Model Of Silica: Thermodynamic Stability Of Zeolite Frameworks As Silica Polymorphs, Peter A. Monson, S. M. Auerbach, M. H. Ford
Further Studies Of A Simple Atomistic Model Of Silica: Thermodynamic Stability Of Zeolite Frameworks As Silica Polymorphs, Peter A. Monson, S. M. Auerbach, M. H. Ford
Peter A. Monson
We have applied our previously reported model of silica based on low coordination and strong association [ J. Chem. Phys. 121, 8415 (2004) ], to the calculation of phase stability of zeolite frameworks SOD, LTA, MFI, and FAU as silica polymorphs. We applied the method of Frenkel and Ladd for calculating free energies of these solids. Our model predicts that the MFI framework structure has a regime of thermodynamic stability at low pressures and above ∼ 1400 K, relative to dense phases such as quartz. In contrast, our calculations predict that the less dense frameworks SOD, LTA, and FAU exhibit …
Synthesis And Adsorption Studies Of The Micro-Mesoporous Material Sba-15, Eunyoung You
Synthesis And Adsorption Studies Of The Micro-Mesoporous Material Sba-15, Eunyoung You
Masters Theses 1911 - February 2014
Over the past decades, there have been worldwide efforts to synthesize new types of ordered porous materials for catalysis, separations, etc. Among those, mesoporous material with microporous walls are promising in a sense that while mesopores act as channels for the reactant transport with little diffusion limitation, micropores in the wall act as active sites for reactions or storage of the molecules. In this study, we focused on the SBA-15 material, which is a highly ordered mesoporous silica material with micropores present in the wall. We have studied the synthesis of the material by manipulating various factors that are known …
Synthesize A Nanoscale Ferrofluid, Rob Snyder
Synthesize A Nanoscale Ferrofluid, Rob Snyder
Nanotechnology Teacher Summer Institutes
The chemical synthesis of a ferrofluid is a nanoscale science activity that originally appears in the Journal of Chemical Education. Access to the following website requires a subscription to the journal. J. Chem. Educ., 76, 943-948 (1999). The article was authored by Jonathan Breitzer and George Lisensky.
Synergies Between Bio- And Oil Refineries For The Production Of Fuels From Biomass, George W. Huber, A. Corma
Synergies Between Bio- And Oil Refineries For The Production Of Fuels From Biomass, George W. Huber, A. Corma
George W. Huber
As petroleum prices continue to increase, it is likely that biofuels will play an ever-increasing role in our energy future. The processing of biomass-derived feedstocks (including cellulosic, starch- and sugar-derived biomass, and vegetable fats) by catalytic cracking and hydrotreating is a promising alternative for the future to produce biofuels, and the existing infrastructure of petroleum refineries is well-suited for the production of biofuels, allowing us to rapidly transition to a more sustainable economy without large capital investments for new reaction equipment. This Review discusses the chemistry, catalysts, and challenges involved in the production of biofuels.
Liquid-Phase Catalytic Processing Of Biomass-Derived Oxygenated Hydrocarbons To Fuels And Chemicals, George W. Huber, J. Chheda, J. A. Dumesic
Liquid-Phase Catalytic Processing Of Biomass-Derived Oxygenated Hydrocarbons To Fuels And Chemicals, George W. Huber, J. Chheda, J. A. Dumesic
George W. Huber
Biomass has the potential to serve as a sustainable source of energy and organic carbon for our industrialized society. The focus of this Review is to present an overview of chemical catalytic transformations of biomass-derived oxygenated feedstocks (primarily sugars and sugar-alcohols) in the liquid phase to value-added chemicals and fuels, with specific examples emphasizing the development of catalytic processes based on an understanding of the fundamental reaction chemistry. The key reactions involved in the processing of biomass are hydrolysis, dehydration, isomerization, aldol condensation, reforming, hydrogenation, and oxidation. Further, it is discussed how ideas based on fundamental chemical and catalytic concepts …
Calculation Of Free Energies And Chemical Potentials For Gas Hydrates Using Monte Carlo Simulations, Peter A. Monson, S. J. Wierzchowski
Calculation Of Free Energies And Chemical Potentials For Gas Hydrates Using Monte Carlo Simulations, Peter A. Monson, S. J. Wierzchowski
Peter A. Monson
We describe a method for calculating free energies and chemical potentials for molecular models of gas hydrate systems using Monte Carlo simulations. The method has two components: (i) thermodynamic integration to obtain the water and guest molecule chemical potentials as functions of the hydrate occupancy; (ii) calculation of the free energy of the zero-occupancy hydrate system using thermodynamic integration from an Einstein crystal reference state. The approach is applicable to any classical molecular model of a hydrate. We illustrate the methodology with an application to the structure-I methane hydrate using two molecular models. Results from the method are also used …
Stability And Transient Dynamics Of Thin Liquid Films Flowing Over Locally Heated Surfaces, N Tiwari, Z Mester, Jm Davis
Stability And Transient Dynamics Of Thin Liquid Films Flowing Over Locally Heated Surfaces, N Tiwari, Z Mester, Jm Davis
Jeffrey M. Davis
The dynamics and linear stability of a liquid film flowing over a locally heated surface are studied using a long-wave lubrication analysis. The temperature gradient at the leading edge of the heater induces a gradient in surface tension that opposes the gravitationally driven flow and leads to the formation of a pronounced capillary ridge. The resulting free-surface shapes are computed, and their stability to spanwise perturbations is analyzed for a range of Marangoni numbers, substrate inclination angles, and temperature profiles. Instability is predicted above a critical Marangoni number for a finite band of wave numbers separated from zero, which is …
Cavitation Rheology For Soft Materials, Jessica A. Zimberlin, Naomi Sanabria-Delong, Gregory N. Tewmassachusetts - Amherst, Alfred J. Crosby
Cavitation Rheology For Soft Materials, Jessica A. Zimberlin, Naomi Sanabria-Delong, Gregory N. Tewmassachusetts - Amherst, Alfred J. Crosby
Gregory N. Tew
To guide the development of tissue scaffolds and the characterization of naturally heterogeneous biological tissues, we have developed a method to determine the local modulus at an arbitrary point within a soft material. The method involves growing a cavity at the tip of a syringe needle and monitoring the pressure of the cavity at the onset of a mechanical instability. This critical pressure is directly related to the local modulus of the material. The results focus on the network development of poly(lactide)–poly(ethylene oxide)–poly(lactide) triblock copolymer and poly(vinyl alcohol) hydrogels. These materials serve as model materials for tissue scaffolds and soft …
Activity Of An Antimicrobial Peptide Mimetic Against Planktonic And Biofilm Cultures Of Oral Pathogens, Nicholas Beckloff, Danielle Laube, Tammy Castro, David Furgang, Steven Park, David Perlin, Dylan Clements, Haizhong Tang, Richard W. Scott, Gregory N. Tew, Gill Diamond
Activity Of An Antimicrobial Peptide Mimetic Against Planktonic And Biofilm Cultures Of Oral Pathogens, Nicholas Beckloff, Danielle Laube, Tammy Castro, David Furgang, Steven Park, David Perlin, Dylan Clements, Haizhong Tang, Richard W. Scott, Gregory N. Tew, Gill Diamond
Gregory N. Tew
Antimicrobial peptides (AMPs) are naturally occurring, broad-spectrum antimicrobial agents that have recently been examined for their utility as therapeutic antibiotics. Unfortunately, they are expensive to produce and are often sensitive to protease digestion. To address this problem, we have examined the activity of a peptide mimetic whose design was based on the structure of magainin, exhibiting its amphiphilic structure. We demonstrate that this compound, meta-phenylene ethynylene (mPE), exhibits antimicrobial activity at nanomolar concentrations against a variety of bacterial and Candida species found in oral infections. Since Streptococcus mutans, an etiological agent of dental caries, colonizes the tooth surface and forms …