Open Access. Powered by Scholars. Published by Universities.®

Biomedical Engineering and Bioengineering Commons

Open Access. Powered by Scholars. Published by Universities.®

Articles 1 - 30 of 154

Full-Text Articles in Biomedical Engineering and Bioengineering

Analyzing Drug Release Kinetics From Water-Soluble Polymers, Sean M. Kelly, Arun K. Upadhyay, Akash Mitra, Balaji Narasimhan Feb 2019

Analyzing Drug Release Kinetics From Water-Soluble Polymers, Sean M. Kelly, Arun K. Upadhyay, Akash Mitra, Balaji Narasimhan

Chemical and Biological Engineering Publications

The ability to develop predictive mathematical models of therapeutic release from pharmaceutical formulations has enormous potential to enhance our understanding of such systems and improve the controlled release of the payload. The current work describes the development and testing of a one-dimensional model of drug transport from amorphous, swelling/dissolving polymers. Model parameters such as the diffusivities of water and drug, the initial loading of the drug, the polymer dissolution rate, drug-polymer interactions, and the tablet thickness were varied, demonstrating the ability to tune the release to be controlled by either drug diffusion or polymer chain disentanglement. In addition, predictions ...


Development Of Gelatin And Graphene-Based Nerve Regeneration Conduits Using 3d Printing Strategies For Electrical Transdifferentiation Of Mesenchymal Stem Cells, Metin Uz, Maxsam Donta, Meryem Mededovic, Donald S. Sakaguchi, Surya Mallapragada Feb 2019

Development Of Gelatin And Graphene-Based Nerve Regeneration Conduits Using 3d Printing Strategies For Electrical Transdifferentiation Of Mesenchymal Stem Cells, Metin Uz, Maxsam Donta, Meryem Mededovic, Donald S. Sakaguchi, Surya Mallapragada

Chemical and Biological Engineering Publications

In this study, gelatin and graphene-based nerve regeneration conduits/scaffolds possessing tailored 3D microstructures and mechanical properties were fabricated using 3D printing. The effect of 3D conduit microstructure and mechanical properties along with the applied electrical stimuli on mesenchymal stem cell (MSCs) behavior and transdifferentiation into Schwann cell (SC)-like phenotypes were investigated. The results indicated that the gelatin conduits/scaffolds had favorable 3D microstructural and mechanical properties for MSC attachment and growth. Immunocytochemistry results demonstrated that the application of electrical stimuli through the conductive graphene within the gelatin-based 3D microstructure had a profound effect on the differentiation of MSCs ...


Interleukin-1 Alpha Increases Anti-Tumor Efficacy Of Cetuximab In Head And Neck Squamous Cell Carcinoma, Madelyn Espinosa-Cotton, Samuel N. Rodman Iii, Kathleen A. Ross, Isaac J. Jensen, Kenley Sangodeyi-Miller, Ayana J. Mclaren, Rachel A. Dahl, Katherine N. Gibson-Corley, Adam T. Koch, Yang-Xin Fu, Vladimir P. Badovinac, Douglas Laux, Balaji Narasimhan, Andrean L. Simons Jan 2019

Interleukin-1 Alpha Increases Anti-Tumor Efficacy Of Cetuximab In Head And Neck Squamous Cell Carcinoma, Madelyn Espinosa-Cotton, Samuel N. Rodman Iii, Kathleen A. Ross, Isaac J. Jensen, Kenley Sangodeyi-Miller, Ayana J. Mclaren, Rachel A. Dahl, Katherine N. Gibson-Corley, Adam T. Koch, Yang-Xin Fu, Vladimir P. Badovinac, Douglas Laux, Balaji Narasimhan, Andrean L. Simons

Chemical and Biological Engineering Publications

Background: Despite the high prevalence of epidermal growth factor receptor (EGFR) overexpression in head and neck squamous cell carcinomas (HNSCCs), incorporation of the EGFR inhibitor cetuximab into the clinical management of HNSCC has not led to significant changes in long-term survival outcomes. Therefore, the identification of novel therapeutic approaches to enhance the clinical efficacy of cetuximab could lead to improved long-term survival for HNSCC patients. Our previous work suggests that EGFR inhibition activates the interleukin-1 (IL-1) pathway via tumor release of IL-1 alpha (IL-1α), although the clinical implications of activating this pathway are unclear in the context of cetuximab therapy ...


Treatment Of Neurodegenerative Disorders Through The Blood-Brain Barrier Using Nanocarriers, Nitya Poovaiah, Zahra Davoudi, Haisheng Peng, Benjamin Schlichtmann, Surya K. Mallapragada, Balaji Narasimhan, Qun Wang Aug 2018

Treatment Of Neurodegenerative Disorders Through The Blood-Brain Barrier Using Nanocarriers, Nitya Poovaiah, Zahra Davoudi, Haisheng Peng, Benjamin Schlichtmann, Surya K. Mallapragada, Balaji Narasimhan, Qun Wang

Chemical and Biological Engineering Publications

Neurodegenerative diseases refer to disorders of the central nervous system (CNS) that are caused by neuronal degradations, dysfunctions, or death. Alzheimer’s disease, Parkinson’s disease, and Huntington’s disease (APHD) are regarded as the three major neurodegenerative diseases. There is a vast body of literature on the causes and treatments of these neurodegenerative diseases. However, the main obstacle in developing an effective treatment strategy is the permeability of the treatment components to the blood-brain barrier (BBB). Several strategies have been developed to improve this obstruction. For example, nanomaterials facilitate drug delivery to the BBB due to their size. They ...


Chemically Modified Gellan Gum Hydrogels With Tunable Properties For Use As Tissue Engineering Scaffolds, Zihao Xu, Zhuqing Li, Shan Jiang, Kaitlin M. Bratlie Jun 2018

Chemically Modified Gellan Gum Hydrogels With Tunable Properties For Use As Tissue Engineering Scaffolds, Zihao Xu, Zhuqing Li, Shan Jiang, Kaitlin M. Bratlie

Chemical and Biological Engineering Publications

Gellan gum is a naturally occurring polymer that can cross-link in the presence of divalent cations to form biocompatible hydrogels. However, physically cross-linked gellan gum hydrogels lose their stability under physiological conditions, thus restricting the applications of these hydrogels in vivo. To improve the mechanical strength of the gels, we incorporated methacrylate into the gellan gum and chemically cross-linked the hydrogel through three polymerization methods: step growth through thiol–ene photoclick chemistry, chain-growth via photopolymerization, and mixed model in which both mechanisms were employed. Methacrylation was confirmed and quantified by proton nuclear magnetic resonance (1H NMR) and Fourier transform infrared ...


Escherichia Coli Attachment To Model Particulates: The Effects Of Bacterial Cell Characteristics And Particulate Properties, Xiao Liang, Chunyu Liao, Michelle L. Soupir, Laura R. Jarboe, Michael L. Thompson, Philip M. Dixon Sep 2017

Escherichia Coli Attachment To Model Particulates: The Effects Of Bacterial Cell Characteristics And Particulate Properties, Xiao Liang, Chunyu Liao, Michelle L. Soupir, Laura R. Jarboe, Michael L. Thompson, Philip M. Dixon

Chemical and Biological Engineering Publications

E. coli bacteria move in streams freely in a planktonic state or attached to suspended particulates. Attachment is a dynamic process, and the fraction of attached microorganisms is thought to be affected by both bacterial characteristics and particulate properties. In this study, we investigated how the properties of cell surfaces and stream particulates influence attachment. Attachment assays were conducted for 77 E. coli strains and three model particulates (ferrihydrite, Ca-montmorillonite, or corn stover) under environmentally relevant conditions. Surface area, particle size distribution, and total carbon content were determined for each type of particulate. Among the three particulates, attachment fractions to ...


Hemolysis As A Rapid Screening Technique For Assessing The Toxicity Of Native Surfactin And A Genetically Engineered Derivative, William J. Colonna, Mustafa E. Marti, John A. Nyman, Chris Green, Charles Glatz Mar 2017

Hemolysis As A Rapid Screening Technique For Assessing The Toxicity Of Native Surfactin And A Genetically Engineered Derivative, William J. Colonna, Mustafa E. Marti, John A. Nyman, Chris Green, Charles Glatz

Chemical and Biological Engineering Publications

If biosurfactants are to achieve their promise in environmental oil-spill remediation, their toxicity to marine life must be assessed. A killifish larvae assay is commonly used as a measure of toxicity but is difficult and nonlinear in response. Red blood cell (RBC) hemolysis has also been the basis for assays of some surfactant levels. Here we present a modified sheep RBC suspension assay and compare its response to that of the fish assay for surfactin and its genetically modified variant fatty-acyl-glutamate (FA-Glu). This is the first report of hemolytic activity as a property of FA-Glu. The method's potential for ...


Improving Escherichia Coli Membrane Integrity And Fatty Acid Production By Expression Tuning Of Fadl And Ompf, Zaigao Tan, William Black, Jong Moon Yoon, Jacqueline V. Shanks, Laura R. Jarboe Feb 2017

Improving Escherichia Coli Membrane Integrity And Fatty Acid Production By Expression Tuning Of Fadl And Ompf, Zaigao Tan, William Black, Jong Moon Yoon, Jacqueline V. Shanks, Laura R. Jarboe

Chemical and Biological Engineering Publications

Background

Construction of microbial biocatalysts for the production of biorenewables at economically viable yields and titers is frequently hampered by product toxicity. Membrane damage is often deemed as the principal mechanism of this toxicity, particularly in regards to decreased membrane integrity. Previous studies have attempted to engineer the membrane with the goal of increasing membrane integrity. However, most of these works focused on engineering of phospholipids and efforts to identify membrane proteins that can be targeted to improve fatty acid production have been unsuccessful.

Results

Here we show that deletion of outer membrane protein ompF significantly increased membrane integrity, fatty ...


Anticancer Drugs, Le Zhao, Zengyi Shao, Jacqueline V. Shanks Jan 2017

Anticancer Drugs, Le Zhao, Zengyi Shao, Jacqueline V. Shanks

Chemical and Biological Engineering Publications

Plant‐derived anticancer drugs play a large role in anticancer pharmaceuticals. Through reviewing the four major types of plant anticancer drugs, namely vinca alkaloids, taxane diterpenoids, podophyllotoxin lignans, and camptothecin quinoline alkaloids, this article illustrates the development process, current status, existing challenges, and future perspective of the plant anticancer drug production. Moreover, this review explains how various biotechnologies, from the mature elicitation strategy to the “omics” techniques that are still undergoing development, can be applied to address the challenges in improving the production of the plant‐sourced anticancer drugs.


Recovery And Utilization Of Lignin Monomers As Part Of The Biorefinery Approach, Kirsten M. Davis, Marjorie Rover, Robert C. Brown, Xianglan Bai, Zhiyou Wen, Laura R. Jarboe Oct 2016

Recovery And Utilization Of Lignin Monomers As Part Of The Biorefinery Approach, Kirsten M. Davis, Marjorie Rover, Robert C. Brown, Xianglan Bai, Zhiyou Wen, Laura R. Jarboe

Chemical and Biological Engineering Publications

Lignin is a substantial component of lignocellulosic biomass but is under-utilized relative to the cellulose and hemicellulose components. Historically, lignin has been burned as a source of process heat, but this heat is usually in excess of the process energy demands. Current models indicate that development of an economically competitive biorefinery system requires adding value to lignin beyond process heat. This addition of value, also known as lignin valorization, requires economically viable processes for separating the lignin from the other biomass components, depolymerizing the lignin into monomeric subunits, and then upgrading these monomers to a value-added product. The fact that ...


High Throughput Studies Of Cell Migration In 3d Microtissues Fabricated By A Droplet Microfluidic Chip, Xiangchen Che, Jacob A. M. Nuhn, Ian C. Schneider, Long Que Jan 2016

High Throughput Studies Of Cell Migration In 3d Microtissues Fabricated By A Droplet Microfluidic Chip, Xiangchen Che, Jacob A. M. Nuhn, Ian C. Schneider, Long Que

Chemical and Biological Engineering Publications

Arrayed three-dimensional (3D) micro-sized tissues with encapsulated cells (microtissues) have been fabricated by a droplet microfluidic chip. The extracellular matrix (ECM) is a polymerized collagen network. One or multiple breast cancer cells were embedded within the microtissues, which were stored in arrayed microchambers on the same chip without ECM droplet shrinkage over 48 h. The migration trajectory of the cells was recorded by optical microscopy. The migration speed was calculated in the range of 3–6 µm/h. Interestingly, cells in devices filled with a continuous collagen network migrated faster than those where only droplets were arrayed in the chambers ...


Responsive Pentablock Copolymers For Sirna Delivery, Surya K. Mallapragada, Metin Uz, Sacide Alsoy Altinkaya Jan 2015

Responsive Pentablock Copolymers For Sirna Delivery, Surya K. Mallapragada, Metin Uz, Sacide Alsoy Altinkaya

Chemical and Biological Engineering Publications

In this study, temperature and pH responsive cationic and amphiphilic pentablock copolymers, which consist of the temperature responsive triblock Pluronic F127 sandwiched between pH responsive PDEAEM (poly(2-diethylaminoethyl methacrylate)) end blocks, were used for the first time in the development of polyplex and gold nanoparticle (AuNP) based multicomponent siRNA delivery systems (MCSs). Copolymers in both systems protected siRNA from external effects, provided cell entry and endosomal escape. The thermoreversible micellization of the hydrophobic PPO block facilitated the cellular entry while the PDEAEM blocks enhanced the endosomal escape through protonated tertiary amine groups by pH buffering. The synergistic advantages of the ...


Epitaxially Grown Collagen Fibrils Reveal Diversity In Contact Guidance Behavior Among Cancer Cells, Juan Wang, Joseph W. Petefish, Andrew C. Hillier, Ian C. Schneider Jan 2015

Epitaxially Grown Collagen Fibrils Reveal Diversity In Contact Guidance Behavior Among Cancer Cells, Juan Wang, Joseph W. Petefish, Andrew C. Hillier, Ian C. Schneider

Chemical and Biological Engineering Publications

Invasion of cancer cells into the surrounding tissue is an important step during cancer progression and is driven by cell migration. Cell migration can be random, but often it is directed by various cues such as aligned fibers composed of extracellular matrix (ECM), a process called contact guidance. During contact guidance, aligned fibers bias migration along the long axis of the fibers. These aligned fibers of ECM are commonly composed of type I collagen, an abundant structural protein around tumors. In this paper, we epitaxially grew several different patterns of organized type I collagen on mica and compared the morphology ...


Hemagglutinin-Based Polyanhydride Nanovaccines Against H5n1 Influenza Elicit Protective Virus Neutralizing Titers And Cell-Mediated Immunity, Kathleen Alaine Ross, Hyelee Park Loyd, Wuwei Wu, Lucas Mark Huntimer, Shaheen Ahmed, Anthony Sambol, Scott Broderick, Zachary Flickinger, Krishna Rajan, Tatiana Bronich, Surya K. Mallapragada, Michael J. Wannemuehler, Susan Long Carpenter, Balaji Narasimhan Jan 2015

Hemagglutinin-Based Polyanhydride Nanovaccines Against H5n1 Influenza Elicit Protective Virus Neutralizing Titers And Cell-Mediated Immunity, Kathleen Alaine Ross, Hyelee Park Loyd, Wuwei Wu, Lucas Mark Huntimer, Shaheen Ahmed, Anthony Sambol, Scott Broderick, Zachary Flickinger, Krishna Rajan, Tatiana Bronich, Surya K. Mallapragada, Michael J. Wannemuehler, Susan Long Carpenter, Balaji Narasimhan

Chemical and Biological Engineering Publications

H5N1 avian influenza is a significant global concern with the potential to become the next pandemic threat. Recombinant subunit vaccines are an attractive alternative for pandemic vaccines compared to traditional vaccine technologies. In particular, polyanhydride nanoparticles encapsulating subunit proteins have been shown to enhance humoral and cell-mediated immunity and provide protection upon lethal challenge. In this work, a recombinant H5 hemagglutinin trimer (H53) was produced and encapsulated into polyanhydride nanoparticles. The studies performed indicated that the recombinant H53 antigen was a robust immunogen. Immunizing mice with H53 encapsulated into polyanhydride nanoparticles induced high neutralizing antibody titers and enhanced CD4+ T ...


Cellular Contractility And Extracellular Matrix Stiffness Regulate Matrix Metalloproteinase Activity In Pancreatic Cancer Cells, Amanda Haage, Ian C. Schneider Aug 2014

Cellular Contractility And Extracellular Matrix Stiffness Regulate Matrix Metalloproteinase Activity In Pancreatic Cancer Cells, Amanda Haage, Ian C. Schneider

Chemical and Biological Engineering Publications

The pathogenesis of cancer is often driven by local invasion and metastasis. Recently, mechanical properties of the tumor microenvironment have been identified as potent regulators of invasion and metastasis, while matrix metalloproteinases (MMPs) are classically known as significant enhancers of cancer cell migration and invasion. Here we have been able to sensitively measure MMP activity changes in response to specific extracellular matrix (ECM) environments and cell contractility states. A pancreatic cancer cell line, Panc-1 cells, up-regulate MMP activities between 3- and 10- fold with increased cell contractility. Conversely, they down-regulate MMP activities when contractility is blocked to levels seen with ...


Characterization Of Sheared Colloidal Aggregation Using Langevin Dynamics Simulation, Sergiy Markutsya, Rodney O. Fox, Shankar Subramaniam Jun 2014

Characterization Of Sheared Colloidal Aggregation Using Langevin Dynamics Simulation, Sergiy Markutsya, Rodney O. Fox, Shankar Subramaniam

Chemical and Biological Engineering Publications

Aggregation of colloidal particles under shear is studied in model systems using a Langevin dynamics model with an improved interparticle interaction potential. In the absence of shear, aggregates that form are characterized by compact structure at small scales and ramified structure at larger scales. This confirms the structural crossover mechanism previously suggested by Sorensen and coworkers, that colloidal aggregation occurs due to monomer addition at small scales and due to cluster-cluster aggregation at large scales. The fractal dimension of nonsheared aggregates is scale-dependent. Smaller aggregates have a higher fractal dimension than larger ones, but the radius of gyration where this ...


The Number Of Lines A Cell Contacts And Cell Contractility Drive The Efficiency Of Contact Guidance, Nicholas R. Romsey, Yue Hou, Laura L. Rodriguez, Ian C. Schneider Mar 2014

The Number Of Lines A Cell Contacts And Cell Contractility Drive The Efficiency Of Contact Guidance, Nicholas R. Romsey, Yue Hou, Laura L. Rodriguez, Ian C. Schneider

Chemical and Biological Engineering Publications

Cell migration is an important biological function that impacts many physiological and pathological processes. Often migration is directed along various densities of aligned fibers of collagen, a process called contact guidance. However, cells adhere to other components in the extracellular matrix, possibly affecting migrational behavior. Additionally, changes in intracellular contractility are well known to affect random migration, but its effect on contact guidance is less known. This study examines differences in directed migration in response to variations in the spacing of collagen, non-specific background adhesion strength and myosin II-mediated contractility. Collagen was microcontact printed onto glass substrates and timelapse live-cell ...


Angle-Tunable Enhanced Infrared Reflection Absorption Spectroscopy Via Grating-Coupled Surface Plasmon Resonance, Joseph W. Petefish, Andrew C. Hillier Jan 2014

Angle-Tunable Enhanced Infrared Reflection Absorption Spectroscopy Via Grating-Coupled Surface Plasmon Resonance, Joseph W. Petefish, Andrew C. Hillier

Chemical and Biological Engineering Publications

Surface enhanced infrared absorption (SEIRA) spectroscopy is an attractive method for increasing the prominence of vibrational modes in infrared spectroscopy. To date, the majority of reports associated with SEIRA utilize localized surface plasmon resonance from metal nanoparticles to enhance electromagnetic fields in the region of analytes. Limited work has been performed using propagating surface plasmons as a method for SEIRA excitation. In this report, we demonstrate angle-tunable enhancement of vibrational stretching modes associated with a thin poly(methyl methacrylate) (PMMA) film that is coupled to a silver-coated diffraction grating. Gratings are fabricated using laser interference lithography to achieve precise surface ...


Nucleation Of Iron Oxide Nanoparticles Mediated By Mms6 Protein In Situ, Sanjay Kashyap, Taylor J. Woehl, Xunpei Liu, Surya K. Mallapragada, Tanya Prozorov Jan 2014

Nucleation Of Iron Oxide Nanoparticles Mediated By Mms6 Protein In Situ, Sanjay Kashyap, Taylor J. Woehl, Xunpei Liu, Surya K. Mallapragada, Tanya Prozorov

Chemical and Biological Engineering Publications

Biomineralization proteins are widely used as templating agents in biomimetic synthesis of a variety of organic-inorganic nanostructures. However, the role of the protein in controlling the nucleation and growth of biomimetic particles is not well understood, because the mechanism of the bioinspired reaction is often deduced from ex situ analysis of the resultant nanoscale mineral phase. Here we report the direct visualization of biomimetic iron oxide nanoparticle nucleation mediated by an acidic bacterial recombinant protein, Mms6, during an in situ reaction induced by the controlled addition of sodium hydroxide to solution-phase Mms6 protein micelles incubated with ferric chloride. Using in ...


Multiple-Input Subject-Specific Modeling Of Plasma Glucose Concentration For Feedforward Control, Kaylee Renee Kotz, Ali Cinar, Yong Mei, Amy Roggendorf, Elizabeth Littlejohn, Laurie Quinn, Derrick K. Rollins Sr. Jan 2014

Multiple-Input Subject-Specific Modeling Of Plasma Glucose Concentration For Feedforward Control, Kaylee Renee Kotz, Ali Cinar, Yong Mei, Amy Roggendorf, Elizabeth Littlejohn, Laurie Quinn, Derrick K. Rollins Sr.

Chemical and Biological Engineering Publications

The ability to accurately develop subject-specific, input causation models, for blood glucose concentration (BGC) for large input sets can have a significant impact on tightening control for insulin dependent diabetes. More specifically, for Type 1 diabetics (T1Ds), it can lead to an effective artificial pancreas (i.e., an automatic control system that delivers exogenous insulin) under extreme changes in critical disturbances. These disturbances include food consumption, activity variations, and physiological stress changes. Thus, this paper presents a free-living, outpatient, multiple-input, modeling method for BGC with strong causation attributes that is stable and guards against overfitting to provide an e ffective ...


A Systems Approach To Designing Next Generation Vaccines: Combining α-Galactose Modified Antigens With Nanoparticle Platforms, Yashdeep Phanse, Brenda Rocio Carrillo-Conde, Amanda Ellen Ramer-Tait, Scott Broderick, Chang Sun Kong, Krishna Rajan, Ramon Flick, Robert B. Mandell, Balaji Narasimhan, Michael J. Wannemuehler Jan 2014

A Systems Approach To Designing Next Generation Vaccines: Combining α-Galactose Modified Antigens With Nanoparticle Platforms, Yashdeep Phanse, Brenda Rocio Carrillo-Conde, Amanda Ellen Ramer-Tait, Scott Broderick, Chang Sun Kong, Krishna Rajan, Ramon Flick, Robert B. Mandell, Balaji Narasimhan, Michael J. Wannemuehler

Chemical and Biological Engineering Publications

Innovative vaccine platforms are needed to develop effective countermeasures against emerging and re-emerging diseases. These platforms should direct antigen internalization by antigen presenting cells and promote immunogenic responses. This work describes an innovative systems approach combining two novel platforms, αGalactose (αGal)-modification of antigens and amphiphilic polyanhydride nanoparticles as vaccine delivery vehicles, to rationally design vaccine formulations. Regimens comprising soluble αGal-modified antigen and nanoparticle-encapsulated unmodified antigen induced a high titer, high avidity antibody response with broader epitope recognition of antigenic peptides than other regimen. Proliferation of antigen-specific CD4 + T cells was also enhanced compared to a traditional ...


Collagen Attachment To The Substrate Controls Cell Clustering Through Migration, Yue Hou, Laura L. Rodriguez, Juan Wang, Ian C. Schneider Jan 2014

Collagen Attachment To The Substrate Controls Cell Clustering Through Migration, Yue Hou, Laura L. Rodriguez, Juan Wang, Ian C. Schneider

Chemical and Biological Engineering Publications

Cell clustering and scattering play important roles in cancer progression and tissue engineering. While the extracellular matrix (ECM) is known to control cell clustering, much of the quantitative work has focused on the analysis of clustering between cells with strong cell-cell junctions. Much less is known about how the ECM regulates cells with weak cell-cell contact. Clustering characteristics were quantified in rat adenocarcinoma cells, which form clusters on physically adsorbed collagen substrates, but not on covalently attached collagen substrates. Covalently attaching collagen inhibited desorption of collagen from the surface. While changes in proliferation rate could not explain differences seen in ...


Development Of A Combined Catalyst And Sorbent For The Water Gas Shift Reaction, Meng Kong, Karl O. Albrecht, Brent H. Shanks, Thomas D. Wheelock Jan 2014

Development Of A Combined Catalyst And Sorbent For The Water Gas Shift Reaction, Meng Kong, Karl O. Albrecht, Brent H. Shanks, Thomas D. Wheelock

Chemical and Biological Engineering Publications

A combined catalyst and sorbent was developed for reacting CO with steam to produce H2 in a single reaction stage at 600 °C by employing the water gas shift (WGS) reaction. The combined material was in the form of spherical pellets where each pellet consisted of a CaO core for absorbing byproduct CO2 surrounded by a porous shell of Al2O 3 which supported a Ni catalyst. The best results were achieved by incorporating 5 wt % limestone in the shell material to suppress coking. By employing the best core-in-shell pellets and supplying a 3:1 mol ratio ...


The Influence Of Alkali And Alkaline Earth Metals And The Role Of Acid Pretreatments In Production Of Sugars From Switchgrass Based On Solvent Liquefaction, Xianglan Bai, Robert C. Brown, Jie Fu, Brent H. Shanks, Matthew Kieffer Jan 2014

The Influence Of Alkali And Alkaline Earth Metals And The Role Of Acid Pretreatments In Production Of Sugars From Switchgrass Based On Solvent Liquefaction, Xianglan Bai, Robert C. Brown, Jie Fu, Brent H. Shanks, Matthew Kieffer

Chemical and Biological Engineering Publications

This study investigated the influence of alkali and alkaline earth metals (AAEM) and the role of acid pretreatments in the production of sugars during solvent liquefaction of lignocellulosic biomass using 1,4-dioxane and water as solvents. The present study found that removal of AAEM by acid washing/water rinsing did not enhance sugar production during solvent liquefaction of pretreated switchgrass nearly to the extent observed for fast pyrolysis nor did it inhibit lignin decomposition, suggesting that AAEM play less of a role in determining product yields in solvent liquefaction. On the other hand, acid infusion greatly enhanced the yields of ...


Cemox-Promoted Ketonization Of Biomass-Derived Carboxylic Acids In The Condensed Phase, Ryan William Snell, Brent H. Shanks Jan 2014

Cemox-Promoted Ketonization Of Biomass-Derived Carboxylic Acids In The Condensed Phase, Ryan William Snell, Brent H. Shanks

Chemical and Biological Engineering Publications

Ketonization of the model bio-oil compound acetic acid was performed in a toluene-solvent condensed phase using five different CeMOx catalysts. The catalysts were characterized using a number of different techniques both before and after reaction testing to gain understanding of how material traits influence their catalytic performance. A number of potentially important catalytic properties were found to be of little importance for the respective reaction. For instance, it was discovered that there was no direct correlation between prereaction surface area with activity for ketonization at high or at low temperatures. Furthermore, better reducibility of the oxide did not appear to ...


Sodium Ion Interactions With Aqueous Glucose: Insights From Quantum Mechanics, Molecular Dynamics, And Experiment, Heather B. Mayes, Jianhui Tian, Michael W. Nolte, Brent H. Shanks, Gregg T. Beckham, S. Gnanakaran, Linda J. Broadbelt Jan 2014

Sodium Ion Interactions With Aqueous Glucose: Insights From Quantum Mechanics, Molecular Dynamics, And Experiment, Heather B. Mayes, Jianhui Tian, Michael W. Nolte, Brent H. Shanks, Gregg T. Beckham, S. Gnanakaran, Linda J. Broadbelt

Chemical and Biological Engineering Publications

In the last several decades, significant efforts have been conducted to understand the fundamental reactivity of glucose derived from plant biomass in various chemical environments for conversion to renewable fuels and chemicals. For reactions of glucose in water, it is known that inorganic salts naturally present in biomass alter the product distribution in various deconstruction processes. However, the molecular-level interactions of alkali metal ions and glucose are unknown. These interactions are of physiological interest as well, for example, as they relate to cation-glucose cotransport. Here, we employ quantum mechanics (QM) to understand the interaction of a prevalent alkali metal, sodium ...


Understanding Biocatalyst Inhibition By Carboxylic Acids, Laura R. Jarboe, Liam Royce, Ping Liu Sep 2013

Understanding Biocatalyst Inhibition By Carboxylic Acids, Laura R. Jarboe, Liam Royce, Ping Liu

Chemical and Biological Engineering Publications

Carboxylic acids are an attractive biorenewable chemical in terms of their flexibility and usage as precursors for a variety of industrial chemicals. It has been demonstrated that such carboxylic acids can be fermentatively produced using engineered microbes, such as Escherichia coli andSaccharomyces cerevisiae. However, like many other attractive biorenewable fuels and chemicals, carboxylic acids become inhibitory to these microbes at concentrations below the desired yield and titer. In fact, their potency as microbial inhibitors is highlighted by the fact that many of these carboxylic acids are routinely used as food preservatives. This review highlights the current knowledge regarding the ...


Influence Of Carbon To Nitrogen Ratios On Soybean Somatic Embryo (Cv. Jack) Growth And Composition, Quyen Xuan Truong, Kaelynn Adele Koch, Jong Moon Yoon, John D. Everard, Jacqueline V. Shanks Jun 2013

Influence Of Carbon To Nitrogen Ratios On Soybean Somatic Embryo (Cv. Jack) Growth And Composition, Quyen Xuan Truong, Kaelynn Adele Koch, Jong Moon Yoon, John D. Everard, Jacqueline V. Shanks

Chemical and Biological Engineering Publications

Soybean [Glycine max (L.) Merr.] seed are valued for their protein and oil content. Soybean somatic embryos cultured in Soybean Histodifferentiation and Maturation (SHaM) medium were examined for their suitability as a model system for developing an understanding of assimilate partitioning and metabolic control points for protein and oil biosynthesis in soybean seed. This report describes the growth dynamics and compositional changes of SHaM embryos in response to change in the carbon to nitrogen ratio of the medium. It was postulated that at media compositions that were sufficient to support maximal growth rates, changes in the C:N ratio are ...


Substrate Binding By The Catalytic Domain And Carbohydrate Binding Module Of Ruminococcus Flavefaciens Fd-1 Xyloglucanase/ Endoglucanase, Christopher D. Warner, Gulden Camci-Unal, Nicola L.B. Pohl, Clark Ford, Peter J. Reilly Jan 2013

Substrate Binding By The Catalytic Domain And Carbohydrate Binding Module Of Ruminococcus Flavefaciens Fd-1 Xyloglucanase/ Endoglucanase, Christopher D. Warner, Gulden Camci-Unal, Nicola L.B. Pohl, Clark Ford, Peter J. Reilly

Chemical and Biological Engineering Publications

Binding and thermodynamic properties of a carbohydrate binding module (CBM) and a glycoside hydrolase family 44 xyloglucanase/endoglucanase catalytic domain (CD) fromRuminococcus flavefaciens, both when separate and when linked to each other, have been quantified when binding various β-1,4-linked glucans and xylans. The three constructs bind cellotetraose, cellopentaose, and cellohexaose with association constants that increase with chain length. The CBM does not bind xylotetraose, xylopentaose, or xylohexaose. The CD appears to bind carboxymethylcellulose (CMC) and xylan only weakly, while the CBM and the CD/CBM bind them much more strongly than they bind the cellooligosaccharides. CMC is bound ...


Simulation Of Mono- And Bidisperse Gas-Particle Flow In A Riser With A Third-Order Quadrature-Based Moment Method, Alberto Passalacqua, Rodney O. Fox Jan 2013

Simulation Of Mono- And Bidisperse Gas-Particle Flow In A Riser With A Third-Order Quadrature-Based Moment Method, Alberto Passalacqua, Rodney O. Fox

Chemical and Biological Engineering Publications

Gas-particle flows can be described by a kinetic equation for the particle phase coupled with the Navier−Stokes equations for the fluid phase through a momentum exchange term. The direct solution of the kinetic equation is prohibitive for most applications due to the high dimensionality of the space of independent variables. A viable alternative is represented by moment methods, where moments of the velocity distribution function are transported in space and time. In this work, a fully coupled third-order, quadrature-based moment method is applied to the simulation of mono- and bidisperse gas-particle flows in the riser of a circulating fluidized ...