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Characterization Of Sheared Colloidal Aggregation Using Langevin Dynamics Simulation, Sergiy Markutsya, Rodney O. Fox, Shankar Subramaniam 2017 Iowa State University

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

Rodney O. Fox

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 ...


Investigation And Engineering Of Polyketide Biosynthetic Pathways, Lei Sun 2017 Utah State University

Investigation And Engineering Of Polyketide Biosynthetic Pathways, Lei Sun

All Graduate Theses and Dissertations

This research is focused on investigation and engineering of natural product biosynthetic pathways for efficient production of pharmaceutically important molecules or generation of new bioactive molecules for drug development.

Natural products are an important source of therapeutics, such as chromomycin (anti-cancer), emodin (anti-inflammatory and anti-tumor) and sprolaxine (anti-Helicobacter pylori). Metabolic engineering of natural product biosynthetic pathways shows its promise for creating and producing valuable compounds with chemical diversity for drug discovery. One goal of this research is to create highly efficient strains to biosynthesize valuable natural products. The engineered Streptomyces roseiscleroticus strain constructed in this work showed higher titers of ...


Gender And Participation In An Engineering Problem-Based Learning Environment, Laura Hirshfield, Milo D. Koretsky 2017 University of Michigan

Gender And Participation In An Engineering Problem-Based Learning Environment, Laura Hirshfield, Milo D. Koretsky

Interdisciplinary Journal of Problem-Based Learning

The use of problem-based learning (PBL) is gaining attention in the engineering classroom as a way to help students synthesize foundational knowledge and to better prepare students for practice. In this work, we study the discourse interactions between 27 student teams and two instructors in an engineering PBL environment to analyze how participation is distributed among team members, paying particular attention to the differences between male and female students. There were no statistically significant differences between the amount that male and female students spoke; however, stereotypical gender roles and traditional gendered behavior did manifest in the discussion. Also, regardless of ...


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 2017 Iowa State University

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 ...


Influence Of Fibroblasts On Functional Arteriogenesis In A Murine Chronic Hindlimb Ischemia Model, Ashli A. Santos 2017 California Polytechnic State University, San Luis Obispo

Influence Of Fibroblasts On Functional Arteriogenesis In A Murine Chronic Hindlimb Ischemia Model, Ashli A. Santos

Biomedical Eng/General Eng.

Peripheral arterial occlusive disease (PAOD) occurs when there is a narrowing or blockage – usually a buildup of plaque - within the arteries that reduces blood flow to tissues which can chronic ischemia. As with most diseases, early detection and proactive treatment are important to maximize prognosis. Exercise effectively treats PAOD, but due to ischemic pain in the limbs, or intermittent claudication (IC), exercise can become painful and difficult. Due to the buildup of plaque, occlusions create an ischemic environment that changes the pressure distribution in collateral networks and increases the shear stress in transverse collaterals. Those two responses signal the beginning ...


The Subject Librarian Newsletter, Engineering And Computer Science, Fall 2017, Buenaventura "Ven" Basco 2017 University of Central Florida

The Subject Librarian Newsletter, Engineering And Computer Science, Fall 2017, Buenaventura "Ven" Basco

Libraries' Newsletters

No abstract provided.


Rice Hull Bioreactor For Recirculating Aquaculture, Marlon A. Greensword 2017 Louisiana State University and Agricultural and Mechanical College

Rice Hull Bioreactor For Recirculating Aquaculture, Marlon A. Greensword

LSU Doctoral Dissertations

The engineering of floating media biofilters has been optimized over the years. The backwashing process has made them more energy and water efficient. Likewise, moving bed bioreactors (MBBR) are gaining interest and popularity because they are relatively affordable to build. Yet, developing countries’ aquaculture production remains largely excluded from the advances made in recirculating aquaculture systems (RAS). This discrepancy is partially driven by the high costs of media such plastic beads and Kaldnes (KMT) media, commonly used in MBBR.

This dissertation evaluates the usability and profitability of rice hulls (RH), an abundant by-product in many developing nations, as a sinking ...


Fundamental Characterization Of Oxygen Nanobubbles, John Hamlin, Yi Wen, Joseph Irudayaraj 2017 Purdue University

Fundamental Characterization Of Oxygen Nanobubbles, John Hamlin, Yi Wen, Joseph Irudayaraj

The Summer Undergraduate Research Fellowship (SURF) Symposium

A hypoxic environment is created by tumors’ incredible growth rate. Hypoxia provides radioresistance to the tumors, thus making radiation treatment less effective. The issue is that increasing the radiation leads to increased side effects in patients. Our goal for the oxygen-filled nanobubble is to deliver oxygen to the tumor to lessen radioresistance and make radiation treatment more efficient. However, we need preliminary research to understand and improve the nanobubbles before further research and implementation. To do this, we synthesized different batches of nanobubbles to optimize the production method and find the best container and temperature to store nanobubbles. We measured ...


The Response Of Schwann Cells To Weak Dc Electric Fields, Alexander T. Lai, Jianming Li 2017 Purdue University

The Response Of Schwann Cells To Weak Dc Electric Fields, Alexander T. Lai, Jianming Li

The Summer Undergraduate Research Fellowship (SURF) Symposium

Schwann cells are glial cells that serve the vital role of supporting neurons in the peripheral nervous system. While their primary function is to provide insulation (myelin) for axons, they also help regenerate injured axons by digesting severed axons and providing scaffolding to guide the regeneration process. This specific role of Schwann cells makes them highly important cellular targets following nerve injury. Although some efforts have been made to encourage Schwann cell migration after nerve damage, the use of electric fields to control cell responses remain unexplored; therefore, this experiment serves to characterize the behavior of Schwann cells to weak ...


Localized Blood Occlusion Generation In An In-Vitro Circulatory Catheter System, Ryan D. Harris, Qi Yang, Hyowon Lee 2017 Purdue University

Localized Blood Occlusion Generation In An In-Vitro Circulatory Catheter System, Ryan D. Harris, Qi Yang, Hyowon Lee

The Summer Undergraduate Research Fellowship (SURF) Symposium

Hydrocephalus is a debilitating neurological disorder that involves the accumulation of cerebrospinal fluid in a ventricle of the brain. The implantation of a catheter commonly treats hydrocephalus with drainage. These catheters have a short lifespan due to obstruction from biological materials. Shunt systems have an extremely high failure rate of more than 40% failed within 1 year and up to 85% failed within 10 years. Previously, polymer-based flexible implantable magnetic micro-actuators were developed to clean up the catheter by mechanical vibration. We have demonstrated clearing of bacteria attachment and are proceeding to examine clearing effects on larger clotting materials, such ...


Establishing A Lung Model For Evaluation Of Engineered Lung Microbiome Therapies, Kathryn F. Atherton, Stephen Miloro, Jenna Rickus 2017 Purdue University

Establishing A Lung Model For Evaluation Of Engineered Lung Microbiome Therapies, Kathryn F. Atherton, Stephen Miloro, Jenna Rickus

The Summer Undergraduate Research Fellowship (SURF) Symposium

Benzene, a toxin and carcinogen found in air polluted by cigarette smoke, car exhaust, and industrial processes, is associated with the development of leukemia and lymphoma. Other than avoiding exposure, there is no current method to deter the effects of benzene. One potential strategy to prevent these effects is to engineer the bacteria of the human lung microbiome to degrade benzene. To evaluate this novel approach, we must verify that the bacteria remain viable within the lung microenvironment. To do so, lungs were harvested from rats and swabbed to determine the contents of the original lung microbiome. Then green fluorescent ...


Pathogenic Dna Detection Using Dna Hairpins: A Non-Linear Hybridization Chain Reaction Platform, Lance Novak, Tamara L. Kinzer-Ursem 2017 Purdue University

Pathogenic Dna Detection Using Dna Hairpins: A Non-Linear Hybridization Chain Reaction Platform, Lance Novak, Tamara L. Kinzer-Ursem

The Summer Undergraduate Research Fellowship (SURF) Symposium

Currently, 3.2 billion people are at risk of being infected with malaria, with 1.2 billion of those being at high risk (>1 in 1000 chance of getting malaria in a year). Thus, there is a need for a biosensor that is highly sensitive, cost effective, and simple to use for point-of-care diagnosis. The biosensing platform, PathVis, has achieved this by measuring changes in fluid properties after a loop-mediated isothermal amplification (LAMP). LAMP is a DNA amplification system that requires enzymes and a temperature of 65degrees C. LAMP currently limits PathVis by being costly, requiring refrigeration, and difficult to ...


Evaluating Thermal Comfort Of Broiler Chickens During Transportation Using Heat Index And Simulated Electronic Chickens, Kaushik Luthra 2017 University of Arkansas, Fayetteville

Evaluating Thermal Comfort Of Broiler Chickens During Transportation Using Heat Index And Simulated Electronic Chickens, Kaushik Luthra

Theses and Dissertations

Broilers experience high physiological stress during pre-slaughter transport, especially under extremes of thermal environment. Characterization of thermal environment on the trailer is crucial to identify stress-prone regions during transportation. At the same time, Broilers experience high physiological stress during pre-slaughter transport, especially under extremes of thermal environment. Characterization of thermal environment on the trailer is crucial to identify stress-prone regions during transportation. At the same time, quantification of heat loss of the broilers loaded on trailers is important in understanding the well-being of the broilers. We have developed four electronic chickens (E-chickens) to simulate the sensible heat loss of live ...


An Automated Device To Increase Screening Throughput Of Zebrafish Larvae, Fuoad Saliou-Sulley 2017 University of Maine

An Automated Device To Increase Screening Throughput Of Zebrafish Larvae, Fuoad Saliou-Sulley

Electronic Theses and Dissertations

The use of the zebrafish as an animal model alternative to mammalian species has spawned research advancements in several medical fields. Since the zebrafish shares a high degree of sequence and functional homology with mammals, studies using this organism can provide in-depth insight into host response to disease and provide a platform for testing a range of treatment options. The optical transparency of zebrafish at early stages of development permits easy assessment of the effects of treatments, occurrence of tumors and other abnormal growth, disease progression, and immune response, to name only a few. These characteristics make it ideal for ...


Enhancing Co-Water Mass Transfer By Functionalized Mcm41 Nanoparticles, Haiyang Zhu, Brent H. Shanks, Theodore J. Heindel 2017 Iowa State University

Enhancing Co-Water Mass Transfer By Functionalized Mcm41 Nanoparticles, Haiyang Zhu, Brent H. Shanks, Theodore J. Heindel

Theodore J. Heindel

Organic groups are grafted to ∼250-nm-diameter MCM41 nanoparticles with a spherical morphology to enhance the CO-water volumetric mass-transfer coefficient (kLa) for synthesis gas fermentation. The results indicate that (i) ∼250-nm MCM41 nanoparticles show a higher kLa value than large silica particles (1.4 and 7 μm), (ii) surface hydroxyl groups on MCM41 nanoparticles play an important role in mass-transfer enhancement, (iii) organic groups grafted to MCM41 modify the mass-transfer enhancement, and (iv) mercaptan groups grafted to MCM41 show the most mass-transfer enhancement of ∼1.9 times that of no nanoparticle addition. The CO-water mass-transfer enhancement depends on the interaction between ...


Effect Of Electrolytes On Co-Water Mass Transfer, Haiyang Zhu, Brent H. Shanks, Theodore J. Heindel 2017 Iowa State University

Effect Of Electrolytes On Co-Water Mass Transfer, Haiyang Zhu, Brent H. Shanks, Theodore J. Heindel

Theodore J. Heindel

The influence of various electrolytes such as sulfate, nitrate, and chloride on CO-water mass transfer was investigated in this study. The results indicate that the enhancement in the CO-water volumetric masstransfer coefficient ranged from 1.5 to 4.7 times that of a baseline system without electrolytes, depending on electrolyte type and concentration. For those electrolytes with the same anions, copper-containing electrolytes provided stronger enhancement, whereas for those electrolytes with the same cations, sulfate-containing electrolytes showed stronger enhancement. By measuring both the CO-water volumetric mass-transfer coefficient (kLa) and the mass-transfer coefficient (kL), it was found that the electrolytes inhibit gas ...


Growth Condition Optimization For Docosahexaenoic Acid (Dha) Production By Moritella Marina Mp-1, Kumar Babu Kautharapu, John A. Rathmacher, Laura R. Jarboe 2017 Iowa State University

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

Laura R. Jarboe

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 ...


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 2017 Iowa State University

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

Laura R. Jarboe

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 ...


Electron Microscopic Observations Of Interfacial Voids In Aluminum Created By Alkaline Dissolution, Saikat Adhikari, L. Scott Chumbley, H. Chen, Y. C. Jean, A. C. Geiculescu, Kurt R. Hebert 2017 Iowa State University

Electron Microscopic Observations Of Interfacial Voids In Aluminum Created By Alkaline Dissolution, Saikat Adhikari, L. Scott Chumbley, H. Chen, Y. C. Jean, A. C. Geiculescu, Kurt R. Hebert

Kurt R. Hebert

We report evidence from electron microscopy and positron annihilation spectroscopy (PAS) for the formation by alkaline dissolution of nm-scale voids in aluminum near the metal-oxide interface. Imaging was carried out using transmission electron microscopy (TEM), scanning transmission electron microscopy (STEM) and field emission scanning electron microscopy (FESEM). EM images supported the PAS finding that voids were found within tens of nm of the interface, and revealed that the void number density increased by at least 10 times due to dissolution. From TEM, void number densities were on the order of 108 cm-2. From TEM and SEM, voids appeared circular in ...


Model For The Steady-State Growth Of Porous Anodic Alumina Films, Jerrod E. Houser, Kurt R. Hebert 2017 Iowa State University

Model For The Steady-State Growth Of Porous Anodic Alumina Films, Jerrod E. Houser, Kurt R. Hebert

Kurt R. Hebert

Simulations were developed for the distributions of electrical potential and incorporated anions in porous anodic alumina (PAA) films during steady-state growth. Predictions of a model for the potential distribution based on Laplace's equation were compared to those of the current continuity equation in conjunction with high-field conduction. It was found that Laplace's equation, which has been used previously in PAA models, resulted in strong violations of charge conservation, when the current density was evaluated using the high field conduction equation. Interface motion predicted by the current continuity equation was nearly uniform except near convex ridges on the metal-film ...


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