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Full-Text Articles in Biomedical Engineering and Bioengineering

Bioengineering Extracellular Matrix Scaffolds For Volumetric Muscle Loss, Kevin Roberts Aug 2019

Bioengineering Extracellular Matrix Scaffolds For Volumetric Muscle Loss, Kevin Roberts

Theses and Dissertations

Volumetric muscle loss overwhelms skeletal muscle’s ordinarily capable regenerative machinery, resulting in fibrosis and severe functional deficits which have defied clinical repair strategies. My work spans the design and preclinical evaluation of implants intended to drive the cell community of injured muscle toward a regenerative state, as well as the development of an understanding of the molecular responses of this cell community to biomaterial interventions. I demonstrate a new class of biomaterial by leveraging the productive capacity of sacrificial hollow fiber membrane cell culture; I show specifically that unique threads of whole extracellular matrix can be isolated by solvent ...


Diffuse Reflectance Spectroscopy To Quantify In Vivo Tissue Optical Properties: Applications In Human Epithelium And Subcutaneous Murine Colon Cancer, Gage Joseph Greening May 2019

Diffuse Reflectance Spectroscopy To Quantify In Vivo Tissue Optical Properties: Applications In Human Epithelium And Subcutaneous Murine Colon Cancer, Gage Joseph Greening

Theses and Dissertations

Colorectal cancer is the 4th most common and 2nd deadliest cancer. Problems exist with predicting which patients will respond best to certain therapy regimens. Diffuse reflectance spectroscopy has been suggested as a candidate to optically monitor a patient’s early response to therapy and has been received favorably in experimentally managing other cancers such as breast and skin. In this dissertation, two diffuse reflectance spectroscopy probes were designed: one with a combined high-resolution microendoscopy modality, and one that was optimized for acquiring data from subcutaneous murine tumors. For both probes, percent errors for estimating tissue optical properties (reduced scattering coefficient ...


Eralpha Isoforms Modulate The Tumorigenicity Of 24r,25(Oh)2d3 In Estrogen-Responsive Cancer, Anjali Verma Jan 2019

Eralpha Isoforms Modulate The Tumorigenicity Of 24r,25(Oh)2d3 In Estrogen-Responsive Cancer, Anjali Verma

Theses and Dissertations

Over 200,000 cases of breast cancer are diagnosed every year. Nearly 20% of these patients supplement their diets with some form of vitamin D. This high frequency of vitamin D supplement use may be due in part to research suggesting that cancer patients with higher serum vitamin D3 levels have better prognoses than patients with low serum vitamin D3. However, double-blind clinical trials on the efficacy of vitamin D3 supplementation in breast cancer have been inconclusive. A recent meta-analysis showed evidence of reduced cancer recurrence in patients taking vitamin D3 supplements who had ‘estrogen receptor ...


Spatiotemporal Modeling And Model Restructuration Approaches In Studies Of Intracellular Signalling Pathways, Md Shahinuzzaman Jan 2019

Spatiotemporal Modeling And Model Restructuration Approaches In Studies Of Intracellular Signalling Pathways, Md Shahinuzzaman

Doctoral Dissertations

"The main focus of the research is to understand the complex phenomena of cell transduction pathways and cell biology in a single cell. Mathematical modeling and experimental evaluation are widely used approaches for this kind of research. Firstly, A multiscale framework for protein-protein interaction has been established using Brownian dynamics algorithm. Sit specific feature, steric collision, diffusion, co-localization and complex formation with time and space has been included in this spatial modeling framework. By implementation of the time adaptive feature in this framework, the computation time reduces in an order of magnitude compared with traditional modeling framework. This multiscale Brownian ...


The Role Of Kras In Mechanosensing In Non-Small Cell Lung Cancer, Krista M. Powell Jan 2019

The Role Of Kras In Mechanosensing In Non-Small Cell Lung Cancer, Krista M. Powell

Theses and Dissertations

Lung cancer is the number one cause of cancer related death worldwide, with more than 1.6 million fatalities each year. Non-small cell lung cancer (NSCLC) accounts for 80-85% of all lung cancers, with KRAS being one of the most prevalent oncogenic driver mutations. Therapeutic approaches for KRAS-mutated NSCLC have been extensively explored due to the US National Cancer Institute RAS Initiative, but methods of directly targeting KRAS or downstream effectors, such as MEK, still have poor results. Previous reports have shown that KRAS-mutated NSCLC activate distinct receptor tyrosine kinases (RTKs) depending on the epithelial or mesenchymal state. Epithelial-to-mesenchymal transition ...


Chemically Modified Monolayer Surfaces Influence Valvular Interstitial Cell Attachment And Differentiation For Heart Valve Tissue Engineering, Matthew N. Rush Dec 2018

Chemically Modified Monolayer Surfaces Influence Valvular Interstitial Cell Attachment And Differentiation For Heart Valve Tissue Engineering, Matthew N. Rush

Nanoscience and Microsystems ETDs

As a cell mediated-process, valvular heart disease (VHD) results in significant morbidity and mortality world-wide. In the US alone, valvular heart disease VHD is estimated to affect 2.5% of the population with a disproportionate impact on an increasing elderly populous. It is well understood that the primary driver for valvular calcification is the differentiation of valvular interstitial cells (VICs) into an osteoblastic-like phenotype. However, the factors leading to the onset of osteoblastic-like VICs (obVICs) and resulting calcification are not fully understood and a more complete characterization of VIC differentiation and phenotypic change is required before treatment of valve disease ...


Direct Quantification Of Deubiquitinating Enzyme Activity In Single Intact Cells, Nora Safabakhsh Aug 2018

Direct Quantification Of Deubiquitinating Enzyme Activity In Single Intact Cells, Nora Safabakhsh

LSU Doctoral Dissertations

Challenges in drug efficacy occur during the treatment of most types of cancer due to the heterogeneity of the tumor microenvironment. This has led to the development of personalized medicine. Due to the clinical success of the proteasome inhibitors Bortezomib and Carfilzomib in treatment of multiple myeloma, interest has shifted towards molecularly-targeted chemotherapeutics for ubiquitin-proteasome system (UPS). Deubiquitinating enzymes (DUBs) are an essential part of this pathway which have been found to promote Bortezomib resistance in multiple myeloma patients. Unfortunately, there is a lack of specific, high throughput biochemical assays to characterize DUB activity in patient samples before and after ...


Determining The Effect Of Locally Delivered Bioactive Modulators On Macrophage Activation At The Implantation Site Of Different Biomaterials In Rats, Kamel Alkhatib Aug 2018

Determining The Effect Of Locally Delivered Bioactive Modulators On Macrophage Activation At The Implantation Site Of Different Biomaterials In Rats, Kamel Alkhatib

Theses and Dissertations

Altering the foreign body reaction by targeting macrophages has been of interest in the biomaterials field to improve the integration of longevity of implanted biomedical devices. The objective of this dissertation was to study the effect of locally delivered bioactive modulators on macrophage activation at the implantation site of different biomaterials in rats. Iloprost, a prostacyclin analog, was tested for its ability to direct macrophages to their pro-wound healing phenotype after the implantation of microdialysis probe in the subcutaneous space of male Sprague Dawley rats. This study showed that iloprost can shift macrophage activation states in vivo to the pro-wound ...


Developing Droplet Based 3d Cell Culture Methods To Enable Investigations Of The Chemical Tumor Microenvironment, Jacqueline A. De Lora Jul 2018

Developing Droplet Based 3d Cell Culture Methods To Enable Investigations Of The Chemical Tumor Microenvironment, Jacqueline A. De Lora

Biomedical Sciences ETDs

Adaptation of cancer cells to changes in the biochemical microenvironment in an expanding tumor mass is a crucial aspect of malignant progression, tumor metabolism, and drug efficacy. In vitro, it is challenging to mimic the evolution of biochemical gradients and the cellular heterogeneity that characterizes cancer tissues found in vivo. It is well accepted that more realistic and controllable in vitro 3D model systems are required to improve the overall cancer research paradigm and thus improve on the translation of results, but multidisciplinary approaches are needed for these advances. This work develops such approaches and demonstrates that new droplet-based cell-encapsulation ...


Mitochondrial Mrna Translation Is Required For Maintenance Of Oxidative Capacity, David Lee May 2018

Mitochondrial Mrna Translation Is Required For Maintenance Of Oxidative Capacity, David Lee

Theses and Dissertations

Oxidative metabolism is required to produce adequate energy to sustain human life. A primary example of deteriorating oxidative capacity is seen in the cardiac musculature during chronic heart failure. This suggests that by improving oxidative potential, chronic heart disease could be mitigated and one approach to accomplish this may be through targeting the mt-mRNA translation system. Purpose: This investigation’s purpose was to characterize disruptions in mt-mRNA translation machinery in multiple forms of cardiomyopathy and to determine if mitochondrial mRNA translation initiation factor (mtIF2) is necessary to maintain oxidative capacity in cardiomyocytes. Methods Using a combination of animal and cell ...


In Situ Designer Lipid Production: Integration Of Novel Characteristics And Behaviors Into Synthetic Cell Membranes, Danielle S. Konetski Jan 2018

In Situ Designer Lipid Production: Integration Of Novel Characteristics And Behaviors Into Synthetic Cell Membranes, Danielle S. Konetski

Chemical & Biological Engineering Graduate Theses & Dissertations

This thesis investigated the coupling of lysolipids and functionalized tails for in situ formation of synthetic liposomes designed to enable specific characteristics or behaviors in applications ranging from drug delivery to the advancement of artificial cell development. Copper-catalyzed Azide-Alkyne Cycloaddition (CuAAC) mediated lipid coupling was improved via incorporation of a photoinitiation system. Here, photo-CuAAC enabled spatiotemporal control over liposome assembly, an over 400-fold increase in formation density, and control over the maximal cross-sectional area of the liposomes formed.

Thiol-Michael mediated lipid coupling was enabled using thiol-functionalized lysolipids and acrylate tails where phospholipids were produced over 48 hours with approximate 90 ...


Modeling Hypertrophic Cardiomyopathy In Neonatal Cardiomyocytes In Cultured In 3d, Esther Choi Jan 2018

Modeling Hypertrophic Cardiomyopathy In Neonatal Cardiomyocytes In Cultured In 3d, Esther Choi

Undergraduate Honors Theses

Heart disease continues to be the leading cause of death in both men and women. It is accompanied with cellular- and organ- level remodeling that cannot be mimicked or recaptured by cells on standard culture platforms. Polyethylene glycol hydrogels bridge this gap by providing user-defined tunability for cell culture. A novel 3D cell culture system was developed to encapsulate neonatal rat ventricular cardiomyocytes (NRVMs) in a single plane, and cell health was assessed. In parallel, recombinant adenoviruses containing the mutations responsible for human hypertrophic cardiomyopathy (HCM) in the beta myosin gene (R403Q and R453C) were generated and used as a ...


Binding Affinity And Specificity Of Sh2 Domain Interactions In Receptor Tyrosine Kinase Signaling Networks, Tom Ronan Dec 2017

Binding Affinity And Specificity Of Sh2 Domain Interactions In Receptor Tyrosine Kinase Signaling Networks, Tom Ronan

Engineering and Applied Science Theses & Dissertations

Receptor tyrosine kinase (RTK) signaling mechanisms play a central role in intracellular signaling and control development of multicellular organisms, cell growth, cell migration, and programmed cell death. Dysregulation of these signaling mechanisms results in defects of development and diseases such as cancer. Control of this network relies on the specificity and selectivity of Src Homology 2 (SH2) domain interactions with phosphorylated target peptides. In this work, we review and identify the limitations of current quantitative understanding of SH2 domain interactions, and identify severe limitations in accuracy and availability of SH2 domain interaction data. We propose a framework to address some ...


Intravenous Administration Of Iron Oxide Nanoparticles In The Chicken Model, Huong Thi Ngoc Le Aug 2017

Intravenous Administration Of Iron Oxide Nanoparticles In The Chicken Model, Huong Thi Ngoc Le

Theses and Dissertations

To be used in health care, the safety and effectiveness of nanoparticles needs to be tested in a living organism. The objective of this project was to develop the chicken as a convenient animal model to examine tissue targeting of intravenously (i.v.)-injected iron oxide (IO) nanoparticles. In Experiment 1, different doses of IO-COOH were i.v. injected into chickens; blood was collected at 0, 5, 15, 30, and 60 minutes post-injection; liver, spleen, lung, and kidney were collected after the last blood collection. For Experiment 2, IO-COOH and IO-PEG were i.v. injected into chickens; blood and the ...


A Multiscale Modeling Study Of The Mammary Gland, Joseph D. Butner Jul 2017

A Multiscale Modeling Study Of The Mammary Gland, Joseph D. Butner

Biomedical Engineering ETDs

Multiscale, hybrid computer modeling has emerged as a valuable tool in the fields of computational systems biology and mathematical oncology. In this work, we present an overview of the motivations for, and development and implementation of, three hybrid multiscale models of the mammary gland system and early stage ductal carcinoma in situ (DCIS) in the gland. Pubertal mammary gland development was described first using a two-dimensional, lattice-based hybrid agent-based model description of the mammary terminal end bud (TEB), and then with a three-dimensional lattice-free TEB model. Both models implement a discrete, agent-based description of the cell scale, and a continuum ...


Optimizing A Standard Fasting Time For 2-Nbdg Uptake Studies In Murine Breast Cancers, Andrew C. Briley May 2017

Optimizing A Standard Fasting Time For 2-Nbdg Uptake Studies In Murine Breast Cancers, Andrew C. Briley

Biomedical Engineering Undergraduate Honors Theses

Recently, there has been a larger use of 2-NBDG, a fluorescent glucose analog, to study glucose uptake in different cell types. These cell types have ranged anywhere from bacteria to human cancer cells. However, there has yet to be a standard procedure and practice for using 2-NBDG. In this study, our goal is to create a standard fasting time for the cells before introducing 2-NBDG to them. This study uses 4T07 cells, a murine breast cancer cell line, to help optimize this fasting time. These cells were fasted at different time points in order to find the ideal fasting time ...


Detection Of Leukocytes Stained With Acridine Orange Using Unique Spectral Features Acquired From An Image-Based Spectrometer, Courtney J. Hunter May 2017

Detection Of Leukocytes Stained With Acridine Orange Using Unique Spectral Features Acquired From An Image-Based Spectrometer, Courtney J. Hunter

Biomedical Engineering Undergraduate Honors Theses

A leukocyte differential count can be used to diagnosis a myriad blood disorders, such as infections, allergies, and efficacy of disease treatments. In recent years, attention has been focused on developing point-of-care (POC) systems to provide this test in global health settings. Acridine orange (AO) is an amphipathic, vital dye that intercalates leukocyte nucleic acids and acidic vesicles. It has been utilized by POC systems to identify the three main leukocyte subtypes: granulocytes, monocytes, and lymphocytes. Subtypes of leukocytes can be characterized using a fluorescence microscope, where the AO has a 450 nm excitation wavelength and has two peak emission ...


Exploring New Therapeutic Strategies For Osteoarthritis: From Genetic Manipulation Of Skeletal Tissues To Chemically-Modified Synthetic Hydrogels, Henry Huang Mar 2017

Exploring New Therapeutic Strategies For Osteoarthritis: From Genetic Manipulation Of Skeletal Tissues To Chemically-Modified Synthetic Hydrogels, Henry Huang

GSBS Dissertations and Theses

Osteoarthritis (OA), a degenerative disease of articular joints, is the leading cause of chronic disability in the US and affects more than a third of adults over 65 years old. Due to the obesity epidemic and an aging population, the prevalence of OA is expected to rise in both young and old adults. There are no disease modifying OA drugs. Therefore, providing any treatment options that delay the onset or progression of OA is highly desirable. The scope of this dissertation examines two different strategies to promote translational therapies for OA. The first approach investigated whether Smad ubiquitin regulatory factor ...


Investigation Of Chitosan-Based Hydrogels As A Cell Delivery Platform For Adipose-Derived Stem/Stromal Cell Transplantation To Promote Angiogenesis In Ischemic Tissues, Jobanpreet Singh Dhillon Mar 2017

Investigation Of Chitosan-Based Hydrogels As A Cell Delivery Platform For Adipose-Derived Stem/Stromal Cell Transplantation To Promote Angiogenesis In Ischemic Tissues, Jobanpreet Singh Dhillon

Electronic Thesis and Dissertation Repository

Stem cell transplantation is under investigation to stimulate angiogenesis in patients with peripheral artery disease. To develop a cell-delivery platform that enhances cell retention and function post-transplantation, the response of human adipose-derived stem/stromal cells (ASCs) encapsulated within N-methacrylate glycol chitosan (MGC) hydrogels with or without integrin-binding RGD or IKVAV motifs was explored. ASC viability was enhanced in the MGC and MGC-RGD hydrogels relative to the MGC-IKVAV group under hypoxic (2% O­2) culture conditions, with cell spreading and higher metabolic activity noted in MGC-RGD at 14 days. Analysis of angiogenic gene expression revealed similar patterns between all hydrogel ...


Protein-Nanoparticle Co-Engineering: Self-Assembly, Intracellular Protein Delivery, And Crispr/Cas9-Based Gene Editing, Rubul Mout Jan 2017

Protein-Nanoparticle Co-Engineering: Self-Assembly, Intracellular Protein Delivery, And Crispr/Cas9-Based Gene Editing, Rubul Mout

Doctoral Dissertations

Direct cytoplasmic delivery of gene editing nucleases such CRISPR/Cas9 systems and therapeutic proteins provides enormous opportunities in curing human genetic diseases, and assist research in basic cell biology. One approach to attain such a goal is through engineering nanotechnological tools to mimic naturally existing intra- and extracellular protein delivery/transport systems. Nature builds transport systems for proteins and other biomolecules through evolution-derived sophisticated molecular engineering. Inspired by such natural assemblies, I employed molecular engineering approaches to fabricate self-assembled nanostructures to use as intracellular protein delivery tools. Briefly, proteins and gold nanoparticles were co-engineered to carry complementary electrostatic recognition elements ...


Biomaterials Approaches For Utilizing The Regenerative Potential Of The Peripheral Nerve Injury Microenvironment, Melissa Renee Wrobel Jan 2017

Biomaterials Approaches For Utilizing The Regenerative Potential Of The Peripheral Nerve Injury Microenvironment, Melissa Renee Wrobel

Wayne State University Dissertations

Clinically available treatments are insufficient to achieve full functional recovery in large (>3cm) peripheral nerve injuries (PNI). The objectives in this thesis were 1) to study often overlooked elements of intrinsic PNI repair including release of inhibitory CSPGs and post-injury responses of inflammatory macrophages and dedifferentiated Schwann cells; 2) to create biomaterial scaf-folds featuring topographical and adhesive cues to enhance neurite outgrowth; and 3) to test the ability of those cues to direct macrophages and Schwann cells towards a pro-regenerative phe-notype. It is hypothesized that recapitulating the positive and negative cues of the PNI microenvi-ronment can better improve regeneration. The ...


Exploring The Production Of Extracellular Matrix By Astrocytes In Response To Mimetic Traumatic Brain Injury, Addison Walker Dec 2016

Exploring The Production Of Extracellular Matrix By Astrocytes In Response To Mimetic Traumatic Brain Injury, Addison Walker

Theses and Dissertations

Following injury to the central nervous system, extracellular modulations are apparent at

the site of injury, often resulting in a glial scar. Astrocytes are mechanosensitive cells, which can create a neuroinhibitory extracellular environment in response to injury. The aim for this research was to gain a fundamental understanding of the affects a diffuse traumatic brain injury has on the astrocyte extracellular environment after injury. To accomplish this, a bioreactor culturing astrocytes in 3D constructs delivered 150G decelerations with 20% biaxial strain to mimic a traumatic brain injury. Experiments were designed to compare the potential effects of media type, number of ...


Mathematical Analysis Of Feedback Targets Of Bmp Signaling In Drosophila Embryonic Development, Yan Luo Dec 2016

Mathematical Analysis Of Feedback Targets Of Bmp Signaling In Drosophila Embryonic Development, Yan Luo

Open Access Theses

Bone morphogenetic proteins (BMPs) drive a range of cellular processes especially in the early stages of embryonic development. This family of proteins acts as one of the most important extracellular signals in development pattern formation across the animal kingdom. Cells in embryos differentiate into different cell types in response to the concentration level of BMP. This complex process is regulated by multiple regulators that serve to tune the signal response.

Extensive experimental and computational research has been performed to analyze BMP regulation in Drosophila, a widely studied model organism, and has advanced our understanding of animal development. Because of BMP ...


Nano Clay-Enhanced Calcium Phosphate Cements And Hydrogels For Biomedical Applications, Udayabhanu Jammalamadaka Jul 2016

Nano Clay-Enhanced Calcium Phosphate Cements And Hydrogels For Biomedical Applications, Udayabhanu Jammalamadaka

Doctoral Dissertations

Biomaterials are used as templates for drug delivery, scaffolds in tissue engineering, grafts in surgeries, and support for tissue regeneration. Novel biomaterial composites are needed to meet multifaceted requirements of compatibility, ease of fabrication and controlled drug delivery. Currently used biomaterials in orthopedics surgeries suffer limitations in toxicity and preventing infections. Polymethyl methacrylate (PMMA) used as bone cement suffers from limitations of thermal necrosis and monomer toxicity calls for development of better cementing biomaterials. A biodegradable/bioresorbable cement with good mechanical properties is needed to address this short coming. Metal implants used in fixing fractures or total joint replacement needs ...


Immunomodulation Of Breast Cancer Cells For Whole Tumor Vaccination, Kristina G. Maxwell May 2016

Immunomodulation Of Breast Cancer Cells For Whole Tumor Vaccination, Kristina G. Maxwell

Biomedical Engineering Undergraduate Honors Theses

Hematogenous metastasis causes 90% of breast cancer-related deaths.Current therapies include chemotherapy and irradiation following surgery. These therapies are very harmful to the human body and do not elicit an anti-tumor immune response. To create a novel therapeutic, an autologous vaccine increasing the immunogenicity of non immunogenic breast cancer cell lines has been proposed.

To create this vaccine, 4T1 mouse mammary breast cancer cells have been selected as the desired cell line to treat. They are non immunogenic and highly invasive. In order to increase their immunogenicity, first projected, was the addition of cytokines to 4T1 cells to increase the ...


An Inquiry Into The Electro-Physiology Of Bacteria, Prasanth Prahladan Apr 2016

An Inquiry Into The Electro-Physiology Of Bacteria, Prasanth Prahladan

Electrical, Computer & Energy Engineering Graduate Theses & Dissertations

This thesis documents the exploration of tools and techniques which were used to determine the existence of patterns within and relationships between the voltage and calcium measurements from individual bacterial cells. The research lies in the broad domain of bacterial electro-physiology.


Bioengineered Platforms To Study Carcinoma Cell Response To Drug Treatment, Thuy V. Nguyen Jan 2016

Bioengineered Platforms To Study Carcinoma Cell Response To Drug Treatment, Thuy V. Nguyen

Doctoral Dissertations

The tumor extracellular matrix (ECM) plays an important role in facilitating tumor growth and mediating tumor cells' resistance to drugs. However, during drug development, potential chemotherapeutics are screened in plastic plates, which lack relevant ECM physicochemical cues. In order to improve drug development process, this dissertation includes the development of relevant 2D and 3D biomaterial systems that can be used to study carcinoma cell response to drug treatment.

A novel poly(ethylene glycol)-phosphorylcholine (PEG-PC) high-throughput biomaterial platform was developed to study how the ECM mechanochemical properties affect cancer cells' response to drug. The PEG-PC biomaterial is optically transparent, has ...


The Role Of Bone Sialoprotein In Periodontal Tissue Development And Bone Repair, Yohannes Soenjaya Dec 2015

The Role Of Bone Sialoprotein In Periodontal Tissue Development And Bone Repair, Yohannes Soenjaya

Electronic Thesis and Dissertation Repository

Bone development and repair involve complex processes that include interaction between cells and their surrounding matrix. In the body, bone sialoprotein (BSP) expression is up-regulated at the onset of mineralization. BSP is a multifunctional acidic phosphoprotein with collagen-binding, hydroxyapatite nucleating, and integrin recognition (RGD sequence, which is important for cell-attachment and signaling) regions. Mice lacking BSP expression (Bsp-/-), exhibit a bone phenotype with reductions in bone mineral density, bone length, osteoclast activation, and impaired bone healing. This thesis examined the role of BSP in tooth development and also its potential use as a therapeutic reagent for bone repair. MicroCT and ...


Compounds Released From Biomass Deconstruction: Understanding Their Effect On Cellulose Enzyme Hydrolysis And Their Biological Activity, Angele Djioleu Dec 2015

Compounds Released From Biomass Deconstruction: Understanding Their Effect On Cellulose Enzyme Hydrolysis And Their Biological Activity, Angele Djioleu

Theses and Dissertations

The effect of compounds produced during biomass pretreatment on cellulolytic enzyme was investigated. Liquid prehydrolyzates were prepared by pretreating switchgrass using 24 combinations of temperature, time, and sulfuric acid concentration based on a full factorial design. Temperature was varied from 140°C to 180°C; time ranged from 10 to 40 min; and the sulfuric acid concentrations were 0.5% or 1% (v/v). Identified products in the prehydrolyzates included xylose, glucose, hydroxymethylfurfural (HMF), furfural, acetic acid, formic acid, and phenolic compounds at concentration ranging from 0 to 21.4 g/L. Pretreatment conditions significantly affected the concentrations of compounds ...


Microengineering The Neural Tube, Christopher Demers Aug 2015

Microengineering The Neural Tube, Christopher Demers

Electronic Theses and Dissertations

Early embryonic development is a complex and highly regulated orchestra of instructive cues that collectively guide naïve stem cells towards progressively more specialized fates. In the neural tube, the precursor structure to the brain and spinal cord, these signals emanate from ‘organizing centers’ surrounding the neural tube. These organizing centers send out soluble cues or morphogens that diffuse tens to hundreds of microns to recipient cells residing in the neural tube. Re-creating this dynamic landscape of cues in vitro is impossible using standard cell culture tools and techniques. However, microfluidics is perfectly suited to fill this gap, allowing precise control ...