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Iowa State University

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Articles 1 - 30 of 58

Full-Text Articles in Biomedical Engineering and Bioengineering

Defining Cell Cluster Size By Dielectrophoretic Capture At An Array Of Wireless Electrodes Of Several Distinct Lengths, Joseph T. Banovetz, Min Li, Darshna Pagariya, Sungu Kim, Baskar Ganapathysubramanian, Robbyn Anand Apr 2019

Defining Cell Cluster Size By Dielectrophoretic Capture At An Array Of Wireless Electrodes Of Several Distinct Lengths, Joseph T. Banovetz, Min Li, Darshna Pagariya, Sungu Kim, Baskar Ganapathysubramanian, Robbyn Anand

Chemistry Publications

Clusters of biological cells play an important role in normal and disease states, such as in the release of insulin from pancreatic islets and in the enhanced spread of cancer by clusters of circulating tumor cells. We report a method to pattern cells into clusters having sizes correlated to the dimensions of each electrode in an array of wireless bipolar electrodes (BPEs). The cells are captured by dielectrophoresis (DEP), which confers selectivity, and patterns cells without the need for physical barriers or adhesive interactions that can alter cell function. Our findings demonstrate that this approach readily achieves fine control of ...


Design And Synthesis Of Multivalent Α-1,2-Trimannose-Linked Bioerodible Microparticles For Applications In Immune Response Studies Of Leishmania Major Infection, Chelsea L. Rintelmann, Tara Grinnage-Pulley, Kathleen Ross, Daniel E. K. Kabotso, Angela Toepp, Anne Cowell, Christine Petersen, Balaji Narasimhan, Nicola Pohl Jan 2019

Design And Synthesis Of Multivalent Α-1,2-Trimannose-Linked Bioerodible Microparticles For Applications In Immune Response Studies Of Leishmania Major Infection, Chelsea L. Rintelmann, Tara Grinnage-Pulley, Kathleen Ross, Daniel E. K. Kabotso, Angela Toepp, Anne Cowell, Christine Petersen, Balaji Narasimhan, Nicola Pohl

Chemical and Biological Engineering Publications

Leishmaniasis, a neglected tropical disease, currently infects approximately 12 million people worldwide with 1 to 2 million new cases each year in predominantly underdeveloped countries. The treatment of the disease is severely underdeveloped due to the ability of the Leishmania pathogen to evade and abate immune responses. In an effort to develop anti-leishmaniasis vaccines and adjuvants, novel carbohydrate-based probes were made to study the mechanisms of immune modulation. In this study, a new bioerodible polyanhydride microparticle was designed and conjugated with a glycodendrimer molecular probe. This molecular probe incorporates a pathogen-like multivalent display of α-1,2-trimannose, for which a more ...


A Photoactivatable Bodipy Probe For Localization‐Based Super‐Resolution Cellular Imaging, Chamari S. Wijesooriya, Julie A. Peterson, Pradeep Shrestha, Elizabeth J. Gehrmann, Arthur H. Winter, Emily Smith Jul 2018

A Photoactivatable Bodipy Probe For Localization‐Based Super‐Resolution Cellular Imaging, Chamari S. Wijesooriya, Julie A. Peterson, Pradeep Shrestha, Elizabeth J. Gehrmann, Arthur H. Winter, Emily Smith

Ames Laboratory Accepted Manuscripts

The synthesis and application of a photoactivatable boron‐alkylated BODIPY probe for localization‐based super‐resolution microscopy is reported. Photoactivation and excitation of the probe is achieved by a previously‐unknown boron‐photodealkylation reaction with a single low‐power visible laser and without requiring the addition of reducing agents or oxygen scavengers in the imaging buffer. These features lead to a versatile probe for localization‐based microscopy of biological systems. The probe can be easily linked to nucleophile‐containing molecules to target specific cellular organelles. By attaching paclitaxel to the photoactivatable BODIPY, in vitro and in vivo super‐resolution imaging ...


Tip-Enhanced Raman Scattering Of Dna Aptamers For Listeria Monocytogenes, Siyu He, Hongyuan Li, Carmen L. Gomes, Dmitri V. Voronine May 2018

Tip-Enhanced Raman Scattering Of Dna Aptamers For Listeria Monocytogenes, Siyu He, Hongyuan Li, Carmen L. Gomes, Dmitri V. Voronine

Mechanical Engineering Publications

Optical detection and conformational mapping of aptamers are important for improving medical and biosensing technologies and for better understanding of biological processes at the molecular level. The authors investigate the vibrational signals of deoxyribonucleic acid aptamers specific to Listeria monocytogenes immobilized on gold substrates using tip-enhanced Raman scattering (TERS) spectroscopy and nanoscale imaging. The authors compare topographic and nano-optical signals and investigate the fluctuations of the position-dependent TERS spectra. They perform spatial TERS mapping with 3 nm step size and discuss the limitation of the resulting spatial resolution under the ambient conditions. TERS mapping provides information about the chemical composition ...


A Contact Formulation Based On A Volumetric Potential: Application To Isogeometric Simulations Of Atrioventricular Valves, David Kamensky, Fei Xue, Chung-Hao Lee, Jinhui Yan, Yuri Bazilevs, Ming-Chen Hsu Mar 2018

A Contact Formulation Based On A Volumetric Potential: Application To Isogeometric Simulations Of Atrioventricular Valves, David Kamensky, Fei Xue, Chung-Hao Lee, Jinhui Yan, Yuri Bazilevs, Ming-Chen Hsu

Mechanical Engineering Publications

This work formulates frictionless contact between solid bodies in terms of a repulsive potential energy term and illustrates how numerical integration of the resulting forces is computationally similar to the “pinball algorithm” proposed and studied by Belytschko and collaborators in the 1990s. We thereby arrive at a numerical approach that has both the theoretical advantages of a potential-based formulation and the algorithmic simplicity, computational efficiency, and geometrical versatility of pinball contact. The singular nature of the contact potential requires a specialized nonlinear solver and an adaptive time stepping scheme to ensure reliable convergence of implicit dynamic calculations. We illustrate the ...


Projection-Based Stabilization Of Interface Lagrange Multipliers In Immersogeometric Fluid–Thin Structure Interaction Analysis, With Application To Heart Valve Modeling, David Kamensky, John A. Evans, Ming-Chen Hsu, Yuri Bazilevs Nov 2017

Projection-Based Stabilization Of Interface Lagrange Multipliers In Immersogeometric Fluid–Thin Structure Interaction Analysis, With Application To Heart Valve Modeling, David Kamensky, John A. Evans, Ming-Chen Hsu, Yuri Bazilevs

Mechanical Engineering Publications

This paper discusses a method of stabilizing Lagrange multiplier fields used to couple thin immersed shell structures and surrounding fluids. The method retains essential conservation properties by stabilizing only the portion of the constraint orthogonal to a coarse multiplier space. This stabilization can easily be applied within iterative methods or semi-implicit time integrators that avoid directly solving a saddle point problem for the Lagrange multiplier field. Heart valve simulations demonstrate applicability of the proposed method to 3D unsteady simulations. An appendix sketches the relation between the proposed method and a high-order-accurate approach for simpler model problems.


Solution Of Population Balance Equations In Applications With Fine Particles: Mathematical Modeling And Numerical Schemes, Tan Trung Nguyen, Frédérique Laurent, Rodney O. Fox, Marc Massot Nov 2016

Solution Of Population Balance Equations In Applications With Fine Particles: Mathematical Modeling And Numerical Schemes, Tan Trung Nguyen, Frédérique Laurent, Rodney O. Fox, Marc Massot

Chemical and Biological Engineering Publications

The accurate description and robust simulation, at relatively low cost, of global quantities (e.g. number density or volume fraction) as well as the size distribution of a population of fine particles in a carrier fluid is still a major challenge for many applications. For this purpose, two types of methods are investigated for solving the population balance equation with aggregation, continuous particle size change (growth and size reduction), and nucleation: the extended quadrature method of moments (EQMOM) based on the work of Yuan et al.[52]and a hybrid method (TSM) between the sectional and moment methods, considering two ...


A Systems Biology Approach Toward Understanding Seed Composition In Soybean, Ling Li, Manhoi Hur, Joon-Yong Lee, Wenxu Zhou, Zhihong Song, Nick Ransom, Cumhur Yusuf Demirkale, Daniel S. Nettleton, Mark E. Westgate, Zebulun Wayne Arendsee, Vidya Vaancheeswaran Iyer, Jacqueline V. Shanks, Basil Nikolau, Eve Wurtele Jan 2015

A Systems Biology Approach Toward Understanding Seed Composition In Soybean, Ling Li, Manhoi Hur, Joon-Yong Lee, Wenxu Zhou, Zhihong Song, Nick Ransom, Cumhur Yusuf Demirkale, Daniel S. Nettleton, Mark E. Westgate, Zebulun Wayne Arendsee, Vidya Vaancheeswaran Iyer, Jacqueline V. Shanks, Basil Nikolau, Eve Wurtele

Biochemistry, Biophysics and Molecular Biology Publications

Background

The molecular, biochemical, and genetic mechanisms that regulate the complex metabolic network of soybean seed development determine the ultimate balance of protein, lipid, and carbohydrate stored in the mature seed. Many of the genes and metabolites that participate in seed metabolism are unknown or poorly defined; even more remains to be understood about the regulation of their metabolic networks. A global omics analysis can provide insights into the regulation of seed metabolism, even without a priori assumptions about the structure of these networks.

Results

With the future goal of predictive biology in mind, we have combined metabolomics, transcriptomics, and ...


Flow Cytometry Is A Promising And Rapid Method For Differentiating Between Freely Suspended Escherichia Coli And E. Coli Attached To Clay Particles, Xiao Liang, Michelle L. Soupir, Shawn M. Rigby, Laura R. Jarboe, Wei Zhang Dec 2014

Flow Cytometry Is A Promising And Rapid Method For Differentiating Between Freely Suspended Escherichia Coli And E. Coli Attached To Clay Particles, Xiao Liang, Michelle L. Soupir, Shawn M. Rigby, Laura R. Jarboe, Wei Zhang

Agricultural and Biosystems Engineering Publications

Aim: A standard procedure does not exist to distinguish between attached and unattached micro-organisms. In this study, we compared two methods to quantify between Escherichia coli attached to clay particles and E. coli freely suspended in solution: flow cytometry (attachment assay and viability assay) and settling (or centrifugation followed by settling).

Methods and Results: Methods were tested using three environmental strains collected from swine facilities (A, B and C) and one purchased modified pathogenic strain (ATCC 43888); four clay particles: Hectorite, Kaolinite, Ca-Montmorillonite, Montmorillonite K-10; and a range of surface area ratios (particle surface area to E. coli surface area ...


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 ...


Fabrication Of Low-Cost Paper-Based Microfluidic Devices By Embossing Or Cut-And-Stack Methods, Martin M. Thuo, Ramses V. Martinez, Wen-Jie Lan, Xinyu Liu, Jabulani Barber, Manza B. Atkinson, Dineth Bandarage, Jean-Francis Bloch, George M. Whitesides Jun 2014

Fabrication Of Low-Cost Paper-Based Microfluidic Devices By Embossing Or Cut-And-Stack Methods, Martin M. Thuo, Ramses V. Martinez, Wen-Jie Lan, Xinyu Liu, Jabulani Barber, Manza B. Atkinson, Dineth Bandarage, Jean-Francis Bloch, George M. Whitesides

Martin M. Thuo

This article describes the use of embossing and “cut-and-stack” methods of assembly, to generate microfluidic devices from omniphobic paper and demonstrates that fluid flowing through these devices behaves similarly to fluid in an open-channel microfluidic device. The porosity of the paper to gases allows processes not possible in devices made using PDMS or other nonporous materials. Droplet generators and phase separators, for example, could be made by embossing “T”-shaped channels on paper. Vertical stacking of embossed or cut layers of omniphobic paper generated three-dimensional systems of microchannels. The gas permeability of the paper allowed fluid in the microchannel to ...


Objective Comparison Of Toolmarks From The Cutting Surfaces Of Slip-Joint Pliers, Taylor Grieve, L. Scott Chumbley, Jim Kreiser, Max Morris, Laura Ekstrand, Song Zhang Apr 2014

Objective Comparison Of Toolmarks From The Cutting Surfaces Of Slip-Joint Pliers, Taylor Grieve, L. Scott Chumbley, Jim Kreiser, Max Morris, Laura Ekstrand, Song Zhang

Ames Laboratory Publications

Experimental results from a statistical analysis algorithm for objectively comparing toolmarks via data files obtained using optical profilometry data are described. The algorithm employed has successfully been used to compare striated marks produced by screwdrivers. In this study, quasi-striated marks produced by the cutting surfaces of slip-joint pliers were examined. Marks were made by cutting both copper and lead wire. Data files were obtained using an optical profilometer that uses focus variation to determine surface roughness. Early efforts using the comparative algorithm yielded inconclusive results when the comparison parameters used were the same as those employed successfully for screw-driver marks ...


Synthesis And Functionalization Of Virus-Mimicking Cationic Block Copolymers With Pathogen-Associated Carbohydrates As Potential Vaccine Adjuvants, J. R. Adams, M. Goswami, N. L.B. Pohl, Surya K. Mallapragada Mar 2014

Synthesis And Functionalization Of Virus-Mimicking Cationic Block Copolymers With Pathogen-Associated Carbohydrates As Potential Vaccine Adjuvants, J. R. Adams, M. Goswami, N. L.B. Pohl, Surya K. Mallapragada

Chemical and Biological Engineering Publications

We report the synthesis of a family of amphiphilic pentablock polymers with different cationic blocks and with controlled architectures as potential vaccine carriers for subunit vaccines. The temperature and pH-dependent micellization and gelation of these pentablock copolymers can provide a depot for sustained protein and gene delivery. The amphiphilic central triblock promotes cellular endocytosis, good gene delivery and has been used effectively as a vaccine adjuvant. The pentablock copolymer outer blocks condense DNA spontaneously as a result of electrostatic interactions for sustained combinational therapy. This family of polymers with different cationic groups was evaluated based on DNA complexation-ability and cytotoxicity ...


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 ...


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 ...


An Rna Aptamer-Based Microcantilever Sensor To Detect The Inflammatory Marker, Mouse Lipocalin-2, Lijie Zhai, Tianjiao Wang, Kyungho Kang, Yue Zhao, Pranav Shrotriya, Marit Nilsen-Hamilton Oct 2012

An Rna Aptamer-Based Microcantilever Sensor To Detect The Inflammatory Marker, Mouse Lipocalin-2, Lijie Zhai, Tianjiao Wang, Kyungho Kang, Yue Zhao, Pranav Shrotriya, Marit Nilsen-Hamilton

Mechanical Engineering Publications

Lipocalin-2 (Lcn2) is a biomarker for many inflammatory-based diseases, including acute kidney injury, cardiovascular stress, diabetes, and various cancers. Inflammatory transitions occur rapidly in kidney and cardiovascular disease, for which an in-line monitor could be beneficial. Microcantilever devices with aptamers as recognition elements can be effective and rapidly responsive sensors. Here, we have selected and characterized an RNA aptamer that specifically binds mouse Lcn2 (mLcn2) with a dissociation constant of 340 ± 70 nM in solution and 38 ± 22 nM when immobilized on a surface. The higher apparent affinity of the immobilized aptamer may result from its effective multivalency that decreases ...


Optimization Of Enzyme Parameters For Fermentative Production Of Biorenewable Fuels And Chemicals, Laura R. Jarboe, Ping Liu, Kumar Babu Kautharapu, Lonnie O. Ingram Oct 2012

Optimization Of Enzyme Parameters For Fermentative Production Of Biorenewable Fuels And Chemicals, Laura R. Jarboe, Ping Liu, Kumar Babu Kautharapu, Lonnie O. Ingram

Chemical and Biological Engineering Publications

Microbial biocatalysts such as Escherichia coli and Saccharomyces cerevisiae have been extensively subjected to Metabolic Engineering for the fermentative production of biorenewable fuels and chemicals. This often entails the introduction of new enzymes, deletion of unwanted enzymes and efforts to fine-tune enzyme abundance in order to attain the desired strain performance. Enzyme performance can be quantitatively described in terms of the Michaelis-Menten type parameters Km, turnover number kcat and Ki, which roughly describe the affinity of an enzyme for its substrate, the speed of a reaction and the enzyme sensitivity to inhibition by regulatory molecules. Here we describe examples of ...


Metabolic Engineering Of Biocatalysts For Carboxylic Acids Production, Ping Liu, Laura R. Jarboe Oct 2012

Metabolic Engineering Of Biocatalysts For Carboxylic Acids Production, Ping Liu, Laura R. Jarboe

Chemical and Biological Engineering Publications

Fermentation of renewable feedstocks by microbes to produce sustainable fuels and chemicals has the potential to replace petrochemical-based production. For example, carboxylic acids produced by microbial fermentation can be used to generate primary building blocks of industrial chemicals by either enzymatic or chemical catalysis. In order to achieve the titer, yield and productivity values required for economically viable processes, the carboxylic acid-producing microbes need to be robust and wellperforming. Traditional strain development methods based on mutagenesis have proven useful in the selection of desirable microbial behavior, such as robustness and carboxylic acid production. On the other hand, rationally-based metabolic engineering ...


High-Throughput Synthesis Of Carbohydrates And Functionalization Of Polyanhydride Nanoparticles, Brenda Rocio Carrillo-Conde, Rajarshi Roychoudhury, Ana Vianey Chavez-Santoscoy, Balaji Narasimhan, Nicola L.B. Pohl Jul 2012

High-Throughput Synthesis Of Carbohydrates And Functionalization Of Polyanhydride Nanoparticles, Brenda Rocio Carrillo-Conde, Rajarshi Roychoudhury, Ana Vianey Chavez-Santoscoy, Balaji Narasimhan, Nicola L.B. Pohl

Chemical and Biological Engineering Publications

Transdisciplinary approaches involving areas such as material design, nanotechnology, chemistry, and immunology have to be utilized to rationally design efficacious vaccines carriers. Nanoparticle-based platforms can prolong the persistence of vaccine antigens, which could improve vaccine immunogenicity 1. Several biodegradable polymers have been studied as vaccine delivery vehicles 1; in particular, polyanhydride particles have demonstrated the ability to provide sustained release of stable protein antigens and to activate antigen presenting cells and modulate immune responses 2-12. The molecular design of these vaccine carriers needs to integrate the rational selection of polymer properties as well as the incorporation of appropriate targeting agents ...


Labeling And Monitoring The Distribution Of Anchoring Sites On Functionalized Cnts By Atomic Layer Deposition, Catherine Marichy, Jean-Philippe Tessonnier, Marta C. Ferro, Kyeong-Hwan Lee, Robert Schlogl, Nicola Pinna, Marc-Georg Willinger Jan 2012

Labeling And Monitoring The Distribution Of Anchoring Sites On Functionalized Cnts By Atomic Layer Deposition, Catherine Marichy, Jean-Philippe Tessonnier, Marta C. Ferro, Kyeong-Hwan Lee, Robert Schlogl, Nicola Pinna, Marc-Georg Willinger

Jean-Philippe Tessonnier

The chemical inertness of graphite and, in the case of tubes, of rolled up few layer graphene sheets, requires some degree of "defect engineering" for the fabrication of carbon based heterostructured materials. It is shown that atomic layer deposition provides a means to specifically label anchoring sites and can be used to characterize the surface functionality of differently treated carbon nanotubes. Direct observation of deposited titania by analytical transmission electron microscopy reveals the location and density of anchoring sites as well as structure related concentrations of functional groups on the surface of the tubes. Controlled functionalization of the tubes therefore ...


Mox/Cnts Hetero-Structures For Gas Sensing Applications: Role Of Cnts Defects, G. Neri, S. G. Leonardi, N. Donato, C. Marichy, Jean-Philippe Tessonnier, M.-G. Willinger, Kyeong-Hwan Lee, N. Pinna Jan 2012

Mox/Cnts Hetero-Structures For Gas Sensing Applications: Role Of Cnts Defects, G. Neri, S. G. Leonardi, N. Donato, C. Marichy, Jean-Philippe Tessonnier, M.-G. Willinger, Kyeong-Hwan Lee, N. Pinna

Jean-Philippe Tessonnier

The preparation, characterization and sensing properties of CNT composites with a thin metal oxide (MOx) surface layer is presented. Atomic layer deposition (ALD) was applied for the coating of the inner and outer CNTs walls with thin films of ZnO and SnO2 of precisely controlled thicknesses. Differently treated CNTs with different degree of surface functionalization were used as support for the oxide films. The sensing properties of the obtained composite materials towards NO2 were investigated and related to the morphological and microstructural characteristics of both the coating and support. SnO2-based composites on CNTs treated at 700 °C show enhanced ...


Edge Cross-Section Profile For Colonoscopic Object Detection, Yi Wang Jan 2012

Edge Cross-Section Profile For Colonoscopic Object Detection, Yi Wang

Graduate Theses and Dissertations

Colorectal cancer is the second leading cause of cancer-related deaths, claiming close to 50,000 lives annually in the United States alone. Colonoscopy is an important screening tool that has contributed to a significant decline in colorectal cancer-related deaths. During colonoscopy, a tiny video camera at the tip of the endoscope generates a video signal of the internal mucosa of the human colon. The video data is displayed on a monitor for real-time diagnosis by the endoscopist. Despite the success of colonoscopy in lowering cancer-related deaths, a significant miss rate for detection of both large polyps and cancers is estimated ...


Dendrimer-Fullerenol Soft-Condensed Nanoassembly, Priyanka Bhattacharya, Seung Ha Kim, Pengyu Chen, Ran Chen, Anne M. Spuches, Jared M. Brown, Monica H. Lamm, Pu Chun Ke Jan 2012

Dendrimer-Fullerenol Soft-Condensed Nanoassembly, Priyanka Bhattacharya, Seung Ha Kim, Pengyu Chen, Ran Chen, Anne M. Spuches, Jared M. Brown, Monica H. Lamm, Pu Chun Ke

Chemical and Biological Engineering Publications

Nanoscale assembly is an area of research that has vast implications for molecular design, sensing, nanofabrication, supramolecular chemistry, catalysis, and environmental remediation. Here we show that poly(amidoamine) (PAMAM) dendrimers of both generations 1 (G1) and 4 (G4) can host 1 fullerenol per 2 dendrimer primary amines as evidenced by isothermal titration calorimetry, dynamic light scattering, and spectrofluorometry. Thermodynamically, the interactions were similarly spontaneous between both generations of dendrimers and fullerenols, however, G4 formed stronger complexes with fullerenols resulting from their higher surface charge density and more internal voids, as demonstrated by spectrofluorometry. In addition to hydrogen bonding that existed ...


Aptamer Functionalized Microcantilever Sensors For Cocaine Detection, Kyungho Kang, Ashish Sachan, Marit Nilsen-Hamilton, Pranav Shrotriya Dec 2011

Aptamer Functionalized Microcantilever Sensors For Cocaine Detection, Kyungho Kang, Ashish Sachan, Marit Nilsen-Hamilton, Pranav Shrotriya

Mechanical Engineering Publications

A cocaine-specific aptamer was used as a receptor molecule in a microcantilever-based surface stress sensor for detection of cocaine molecules. An interferometric technique that relies on measuring differential displacement between two microcantilevers (a sensing/reference pair) was utilized to measure the cocaine/aptamer binding induced surface stress changes. Sensing experiments were performed for different concentrations of cocaine from 25 to 500 μM in order to determine the sensor response as a function of cocaine concentration. In the lower concentration range from 25 to 100 μM, surface stress values increased proportionally to coverage of aptamer/cocaine complexes from 11 to 26 ...


An Algorithm For Optimally Fitting A Wiener Model, Lucas P. Beverlin, Derrick K. Rollins Sr., Nisarg Vyas, David Andre Jan 2011

An Algorithm For Optimally Fitting A Wiener Model, Lucas P. Beverlin, Derrick K. Rollins Sr., Nisarg Vyas, David Andre

Chemical and Biological Engineering Publications

The purpose of this work is to present a new methodology for fitting Wiener networks to datasets with a large number of variables. Wiener networks have the ability to model a wide range of data types, and their structures can yield parameters with phenomenological meaning. There are several challenges to fitting such a model: model stiffness, the nonlinear nature of a Wiener network, possible overfitting, and the large number of parameters inherent with large input sets. This work describes a methodology to overcome these challenges by using several iterative algorithms under supervised learning and fitting subsets of the parameters at ...


Mannose-Functionalized "Pathogen-Like" Polyanhydride Nanoparticles Target C-Type Lectin Receptors On Dendritic Cells, Brenda Rocio Carrillo-Conde, Eun-Ho Song, Ana Vianey Chavez-Santoscoy, Yashdeep Phanse, Amanda Ellen Ramer-Tait, Nicola L.B. Pohl, Michael J. Wannemuehler, Bryan H. Bellaire, Balaji Narasimhan Jan 2011

Mannose-Functionalized "Pathogen-Like" Polyanhydride Nanoparticles Target C-Type Lectin Receptors On Dendritic Cells, Brenda Rocio Carrillo-Conde, Eun-Ho Song, Ana Vianey Chavez-Santoscoy, Yashdeep Phanse, Amanda Ellen Ramer-Tait, Nicola L.B. Pohl, Michael J. Wannemuehler, Bryan H. Bellaire, Balaji Narasimhan

Chemical and Biological Engineering Publications

Targeting pathogen recognition receptors on dendritic cells (DCs) offers the advantage of triggering specific signaling pathways to induce a tailored and robust immune response. In this work, we describe a novel approach to targeted antigen delivery by decorating the surface of polyanhydride nanoparticles with specific carbohydrates to provide "pathogen-like" properties that ensure nanoparticles engage C-type lectin receptors on DCs. The surface of polyanhydride nanoparticles was functionalized by covalent linkage of dimannose and lactose residues using an amine-carboxylic acid coupling reaction. Coculture of functionalized nanoparticles with bone marrow-derived DCs significantly increased cell surface expression of MHC II, the T cell costimulatory ...


A Method To Quantify Mixing In A Two Component Fluidized Bed, Norman K. Keller, Theodore J. Heindel Aug 2010

A Method To Quantify Mixing In A Two Component Fluidized Bed, Norman K. Keller, Theodore J. Heindel

Mechanical Engineering Conference Presentations, Papers, and Proceedings

Fluidized bed technology can be used for pyrolysis and gasification of solid fuel particles such as biomass, which is important to industry because of its potential as an alternative for petroleum-based fuels. To efficiently utilize a fluidized bed reactor it is necessary, among other factors, to investigate the mixing and segregation behavior of the fuel particles with the bed material. In order to characterize the material distribution, a technique to visualize the biomass inside a fluidized bed reactor has been developed using X-ray computed tomography (CT) scans. This paper presents an image analysis procedure that can be used to quantify ...


Utilizing Protein-Lean Coproducts From Corn Containing Recombinant Pharmaceutical Proteins For Ethanol Production, Ilankovan Paraman, Lorena Beatriz Moeller, M. Paul Scott, Kan Wang, Charles E. Glatz, Lawrence A. Johnson Jan 2010

Utilizing Protein-Lean Coproducts From Corn Containing Recombinant Pharmaceutical Proteins For Ethanol Production, Ilankovan Paraman, Lorena Beatriz Moeller, M. Paul Scott, Kan Wang, Charles E. Glatz, Lawrence A. Johnson

Chemical and Biological Engineering Publications

Protein-lean fractions of corn (maize) containing recombinant (r) pharmaceutical proteins were evaluated as a potential feedstock to produce fuel ethanol. The levels of residual r-proteins in the coproduct, distillers dry grains with solubles (DDGS), were determined. Transgenic corn lines containing recombinant green fluorescence protein (r-GFP) and a recombinant subunit vaccine of Escherichia coli enterotoxin (r-LTB), primarily expressed in endosperm, and another two corn lines containing recombinant human collagen (r-CIα1) andr-GFP, primarily expressed in germ, were used as model systems. The kernels were either ground and used for fermentation or dry fractionated to recover germ-rich ...


Sulfated Zirconia Modified Sba-15 Catalysts For Cellobiose Hydrolysis, Volkan Degirmenci, Deniz Uner, Basak Cinlar, Brent H. Shanks, Aysen Yilmaz, Rutget A. Van Santen, Emiel J. M. Hensen Jan 2010

Sulfated Zirconia Modified Sba-15 Catalysts For Cellobiose Hydrolysis, Volkan Degirmenci, Deniz Uner, Basak Cinlar, Brent H. Shanks, Aysen Yilmaz, Rutget A. Van Santen, Emiel J. M. Hensen

Chemical and Biological Engineering Publications

Zirconia modified SBA-15 becomes a very active catalyst for the selective hydrolysis of cellobiose to glucose after sulfation. Spectroscopic investigations indicate the presence of Brønsted acid sites with similar properties to those present in conventional sulfated zirconia. Indications are found that the sulfate groups attached to zirconia interact with silanol groups of SBA-15. The catalytic activity in cellobiose hydrolysis correlates well with results for temperature-programmed decomposition of i-propylamine for a range of sulfated ZrO2/SBA-15 catalysts. A glucose yield of 60% during cellobiose hydrolysis at a reaction time of 90 min at 160° C is obtained.