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

Biomedical Engineering and Bioengineering Commons

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

Articles 1 - 17 of 17

Full-Text Articles in Biomedical Engineering and Bioengineering

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 ...


Integrated Self-Assembly Of The Mms6 Magnetosome Protein To Form An Iron-Responsive Structure, Shuren Feng, Lijun Wang, Pierre Palo, Xunpei Liu, Surya K. Mallapragada, Marit Nilsen-Hamilton Jan 2013

Integrated Self-Assembly Of The Mms6 Magnetosome Protein To Form An Iron-Responsive Structure, Shuren Feng, Lijun Wang, Pierre Palo, Xunpei Liu, Surya K. Mallapragada, Marit Nilsen-Hamilton

Chemical and Biological Engineering Publications

A common feature of biomineralization proteins is their self-assembly to produce a surface consistent in size with the inorganic crystals that they produce. Mms6, a small protein of 60 amino acids from Magnetospirillum magneticum strain AMB-1 that promotes the in vitro growth of superparamagnetic magnetite nanocrystals, assembles in aqueous solution to form spherical micelles that could be visualized by TEM and AFM. The results reported here are consistent with the view that the N and C-terminal domains interact with each other within one polypeptide chain and across protein units in the assembly. From studies to determine the amino acid residues ...


Combinatorial Evaluation Of In Vivo Distribution Of Polyanhydride Particle-Based Platforms For Vaccine Delivery, Latrisha K. Petersen, Lucas Mark Huntimer, Katharine Walz, Amanda Ellen Ramer-Tait, Michael J. Wannemuehler, Balaji Narasimhan Jan 2013

Combinatorial Evaluation Of In Vivo Distribution Of Polyanhydride Particle-Based Platforms For Vaccine Delivery, Latrisha K. Petersen, Lucas Mark Huntimer, Katharine Walz, Amanda Ellen Ramer-Tait, Michael J. Wannemuehler, Balaji Narasimhan

Chemical and Biological Engineering Publications

Several challenges are associated with current vaccine strategies, including repeated immunizations, poor patient compliance, and limited approved routes for delivery, which may hinder induction of protective immunity. Thus, there is a need for new vaccine adjuvants capable of multi-route administration and prolonged antigen release at the site of administration by providing a depot within tissue. In this work, we designed a combinatorial platform to investigate the in vivo distribution, depot effect, and localized persistence of polyanhydride nanoparticles as a function of nanoparticle chemistry and administration route. Our observations indicated that the route of administration differentially affected tissue residence times. All ...


Tin Dioxide-Carbon Heterostructures Applied To Gas Sensing: Structure-Dependent Properties And General Sensing Mechanism, Catherine Marichy, Patricia A. Russo, Mariangela Latino, Jean-Philippe Tessonnier, Marc-Georg Wilinger, Nicola Donato, Giovanni Neri, Nicola Pinna Jan 2013

Tin Dioxide-Carbon Heterostructures Applied To Gas Sensing: Structure-Dependent Properties And General Sensing Mechanism, Catherine Marichy, Patricia A. Russo, Mariangela Latino, Jean-Philippe Tessonnier, Marc-Georg Wilinger, Nicola Donato, Giovanni Neri, Nicola Pinna

Chemical and Biological Engineering Publications

Carbon materials such as carbon nanotubes (CNTs), graphene, and reduced graphene oxide (RGO) exhibit unique electrical properties, which are also influenced by the surrounding atmosphere. They are therefore promising sensing materials. Despite the existence of studies reporting the gas-sensing properties of metal oxide (MOx) coated nanostructured carbon, an incomplete understanding of their sensing mechanism remains. Here we report a systematic study on the preparation, characterization, and sensing properties of CNT and RGO composites with SnO2 coating. Atomic layer deposition (ALD) was applied to the conformal coating of the inner and outer walls of CNTs with thin films of SnO2 of ...


Insights Into The Ceria-Catalyzed Ketonization Reaction For Biofuels Applications, Ryan William Snell, Brent H. Shanks Jan 2013

Insights Into The Ceria-Catalyzed Ketonization Reaction For Biofuels Applications, Ryan William Snell, Brent H. Shanks

Chemical and Biological Engineering Publications

The ketonization of small organic acids is a valuable reaction for biorenewable applications. Ceria has long been used as a catalyst for this reaction; however, under both liquid and vapor phase conditions, it was found that given the right temperature regime of about 150-300 °C, cerium oxide, which was previously believed to be a stable catalyst for ketonization, can undergo bulk transformations. This result, along with other literature reports, suggest that the long held belief of two separate reaction pathways for either bulk or surface ketonization reactions are not required to explain the interaction of cerium oxide with organic acids ...


Growth Condition Optimization For Docosahexaenoic Acid (Dha) Production By Moritella Marina Mp-1, Kumar Babu Kautharapu, John A. Rathmacher, Laura R. Jarboe Jan 2013

Growth Condition Optimization For Docosahexaenoic Acid (Dha) Production By Moritella Marina Mp-1, Kumar Babu Kautharapu, John A. Rathmacher, Laura R. Jarboe

Chemical and Biological Engineering Publications

The marine organism Moritella marina MP-1 produces the polyunsaturated fatty acid docosahexaenoic acid (DHA). While the basic metabolic pathway for DHA production in this organism has been identified, the impact of growth conditions on DHA production is largely unknown. This study examines the effect of supplemental carbon, nitrogen and salts, growth temperature and media composition and pH on DHA and biomass production and the fatty acid profile. The addition of supplemental nitrogen significantly increased the overall DHA titer via an increase in biomass production. Supplemental glucose or glycerol increased biomass production, but decreased the amount of DHA per biomass, resulting ...


High Rate Detection Of Volatile Products Using Differential Electrochemical Mass Spectrometry: Combining An Electrode-Coated Membrane With Hydrodynamic Flow In A Wall-Tube Configuration, Subramanian Venkatachalam, Robert J. Angelici, L. Keith Woo, Andrew C. Hillier Jan 2013

High Rate Detection Of Volatile Products Using Differential Electrochemical Mass Spectrometry: Combining An Electrode-Coated Membrane With Hydrodynamic Flow In A Wall-Tube Configuration, Subramanian Venkatachalam, Robert J. Angelici, L. Keith Woo, Andrew C. Hillier

Chemical and Biological Engineering Publications

We present an experimental system that combines differential electrochemical mass spectrometry with hydrodynamic flow consisting of an impinging jet in a wall-tube configuration. This assembly allows simultaneous detection of electrochemical signals along with monitoring of dissolved gas species using differential electrochemical mass spectrometry under well-defined hydrodynamic conditions and over a wide range of mass transfer rates. The working electrode is deposited directly onto a thin, hydrophobic membrane, which also serves as the inlet to the mass spectrometer. This inlet provides extremely rapid mass detection as well as a high flux of products from the electrode surface into the mass spectrometer ...


Evaluation Of Coarse-Grained Mapping Schemes For Polysaccharide Chains In Cellulose, Sergiy Markutsya, Ajitha Devarajan, John Ysrael Baluyut, Theresa Lynn Windus, Mark S. Gordon, Monica H. Lamm Jan 2013

Evaluation Of Coarse-Grained Mapping Schemes For Polysaccharide Chains In Cellulose, Sergiy Markutsya, Ajitha Devarajan, John Ysrael Baluyut, Theresa Lynn Windus, Mark S. Gordon, Monica H. Lamm

Chemical and Biological Engineering Publications

A fundamental understanding of the intermolecular forces that bind polysaccharide chains together in cellulose is crucial for designing efficient methods to overcome the recalcitrance of lignocellulosic biomass to hydrolysis. Because the characteristic time and length scales for the degradation of cellulose by enzymatic hydrolysis or chemical pretreatment span orders of magnitude, it is important to closely integrate the molecular models used at each scale so that, ultimately, one may switch seamlessly between quantum, atomistic, and coarse-grained descriptions of the system. As a step towards that goal, four multiscale coarse-grained models for polysaccharide chains in a cellulose-Iα microfiber are considered. Using ...


The Orca2 Transcription Factor Plays A Key Role In Regulation Of The Terpenoid Indole Alkaloid Pathway, Chun Yao Li, Alex L. Leopold, Guy W. Sander, Jacqueline V. Shanks, Le Zhao, Susan I. Gibson Jan 2013

The Orca2 Transcription Factor Plays A Key Role In Regulation Of The Terpenoid Indole Alkaloid Pathway, Chun Yao Li, Alex L. Leopold, Guy W. Sander, Jacqueline V. Shanks, Le Zhao, Susan I. Gibson

Chemical and Biological Engineering Publications

Background: The terpenoid indole alkaloid (TIA) pathway leads to the production of pharmaceutically important drugs, such as the anticancer compounds vinblastine and vincristine. Unfortunately, these drugs are produced in trace amounts, causing them to be very costly. To increase production of these drugs, an improved understanding of the TIA regulatory pathway is needed. Towards this end, transgenic Catharanthus roseus hairy roots that overexpress the ORCA2 TIA transcriptional activator were generated and characterized.Results: Transcriptional profiling experiments revealed that overexpression of ORCA2 results in altered expression of key genes from the indole and terpenoid pathways, which produce precursors for the TIA ...


Hybrid Hydroxyapatite Nanoparticle Colloidal Gels Are Injectable Fillers For Bone Tissue Engineering, Qun Wang, Zhen Gu, Syed Jamal, Michael S. Detamore, Cory Berkland Jan 2013

Hybrid Hydroxyapatite Nanoparticle Colloidal Gels Are Injectable Fillers For Bone Tissue Engineering, Qun Wang, Zhen Gu, Syed Jamal, Michael S. Detamore, Cory Berkland

Chemical and Biological Engineering Publications

Injectable bone fillers have emerged as an alternative to the invasive surgery often required to treat bone defects. Current bone fillers may benefit from improvements in dynamic properties such as shear thinning during injection and recovery of material stiffness after placement. Negatively charged inorganic hydroxyapatite (HAp) nanoparticles (NPs) were assembled with positively charged organic poly(d,l-lactic-co-glycolic acid) (PLGA) NPs to create a cohesive colloidal gel. This material is held together by electrostatic forces that may be disrupted by shear to facilitate extrusion, molding, or injection. Scanning electron micrographs of the dried colloidal gels showed a well-organized, three-dimensional porous structure ...


Injectable Nano-Network For Glucose-Mediated Insulin Delivery, Zhen Gu, Alex A. Aimetti, Qun Wang, Tram T. Dang, Yunlong Zhang, Omid Veiseh, Hao Cheng, Robert S. Langer, Daniel G. Anderson Jan 2013

Injectable Nano-Network For Glucose-Mediated Insulin Delivery, Zhen Gu, Alex A. Aimetti, Qun Wang, Tram T. Dang, Yunlong Zhang, Omid Veiseh, Hao Cheng, Robert S. Langer, Daniel G. Anderson

Chemical and Biological Engineering Publications

Diabetes mellitus, a disorder of glucose regulation, is a global burden affecting 366 million people across the world. An artificial “closed-loop” system able to mimic pancreas activity and release insulin in response to glucose level changes has the potential to improve patient compliance and health. Herein we develop a glucose-mediated release strategy for the self-regulated delivery of insulin using an injectable and acid-degradable polymeric network. Formed by electrostatic interaction between oppositely charged dextran nanoparticles loaded with insulin and glucose-specific enzymes, the nanocomposite-based porous architecture can be dissociated and subsequently release insulin in a hyperglycemic state through the catalytic conversion of ...


Hypoglycemia Early Alarm Systems Based On Multivariable Models, Kamuran Turksoy, Elif S. Bayrak, Lauretta Quinn, Elizabeth Littlejohn, Derrick K. Rollins Sr., Ali Cinar Jan 2013

Hypoglycemia Early Alarm Systems Based On Multivariable Models, Kamuran Turksoy, Elif S. Bayrak, Lauretta Quinn, Elizabeth Littlejohn, Derrick K. Rollins Sr., Ali Cinar

Chemical and Biological Engineering Publications

Hypoglycemia is a major challenge of artificial pancreas systems and a source of concern for potential users and parents of young children with Type 1 diabetes (T1D). Early alarms to warn of the potential of hypoglycemia are essential and should provide enough time to take action to avoid hypoglycemia. Many alarm systems proposed in the literature are based on interpretation of recent trends in glucose values. In the present study, subject-specific recursive linear time series models are introduced as a better alternative to capture glucose variations and predict future blood glucose concentrations. These models are then used in hypoglycemia early ...


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 ...


A Hierarchy Of Eulerian Models For Trajectory Crossing In Particle-Laden Turbulent Flows Over A Wide Range Of Stokes Numbers, Frederique Laurent, Aymeric Vie, Christophe Chalons, Rodney O. Fox, Marc Massot Jan 2013

A Hierarchy Of Eulerian Models For Trajectory Crossing In Particle-Laden Turbulent Flows Over A Wide Range Of Stokes Numbers, Frederique Laurent, Aymeric Vie, Christophe Chalons, Rodney O. Fox, Marc Massot

Chemical and Biological Engineering Publications

With the large increase in available computational resources, large-eddy simulation (LES) of industrial configurations has become an efficient and tractable alternative to traditional multiphase turbulence models. Many applications involve a liquid or solid disperse phase carried by a gas phase (eg, fuel injection in automotive or aeronautical engines, fluidized beds, and alumina particles in rocket boosters).


Use Of Dispersion Imaging For Grating-Coupled Surface Plasmon Resonance Sensing Of Multilayer Langmuir–Blodgett Films, Wei-Hsun Yeh, Andrew C. Hillier Jan 2013

Use Of Dispersion Imaging For Grating-Coupled Surface Plasmon Resonance Sensing Of Multilayer Langmuir–Blodgett Films, Wei-Hsun Yeh, Andrew C. Hillier

Chemical and Biological Engineering Publications

We report grating-coupled surface plasmon resonance measurements involving the use of dispersion images to interpret the optical response of a metal-coated grating. Optical transmission through a grating coated with a thin, gold film exhibits features characteristic of the excitation of surface plasmon resonance due to coupling with the nanostructured grating surface. Evidence of numerous surface plasmon modes associated with coupling at both front (gold/air) and back (gold/substrate) grating interfaces is observed. The influence of wavelength and angle of incidence on plasmon coupling can be readily characterized via dispersion images, and the associated image features can be indexed to ...