Biomedical Engineering and Bioengineering Commons^™

Isolation Of Natural Nrf2 Activators From American Ginseng, Akrm Abdalrahman

Theses and Dissertations

Nuclear factor erythroid-2 related factor 2 (Nrf2), a major transcription factor of the endogenous antioxidant defense system, has been proposed as a potential therapeutic target for the treatment of various diseases. However, a small molecule-driven Nrf2 signaling therapeutic approach remains to be established. Herein, we report one such possibility discovered by the bioassay-based fractionation of American ginseng. Since crude extract of American ginseng was found to suppress the expression of inducible nitric oxide synthase (iNOS) in lipopolysaccharide (LPS)-inflamed macrophages via activating Nrf2, we further fractioned the crude extract using solvents including hexane, dichloromethane, ethyl acetate, butanol, and water, and found …

Discovery And Characterization Of Multi-Target Directed Ligands As Inhibitors Of Amyloid-Β Aggregation And Regulators Of Alzheimer's Disease, Jui-Heng Tseng

Theses and Dissertations

Alzheimer's disease (AD) is the most common neurodegenerative disease in the world. As the disease advances, symptoms include confusion, language skill breakdown, and long term memory loss - and culminate in death. Existing therapies for AD provide symptomatic benefits but cannot halt or slow the disease pathogenesis.

Increasing evidence reveals the multi-factorial nature of AD. Numerous factors, including amyloid-β (Aβ) aggregation, calcium homeostasis dysregulation, and oxidative stress, contribute to disease development and interplay with each other. Therefore, multi-target directed ligands (MTDLs) may present an effective AD treatment. Among all factors, Aβ aggregation is suggested to play the most crucial role. …

3d Conductive Nanocomposite Scaffold For Bone Tissue Engineering, Aref Shahini, Mostafa Yazdimamaghani, Kenneth J. Walker, Margaret A. Eastman, Hamed Hatami-Marbini, Brenda J. Smith, John L. Ricci, Sundar V. Madihally, Daryoosh Vashaee, Lobat Tayebi

Chemical and Biochemical Engineering Faculty Research & Creative Works

Bone healing can be significantly expedited by applying electrical stimuli in the injured region. Therefore, a three-dimensional (3D) ceramic conductive tissue engineering scaffold for large bone defects that can locally deliver the electrical stimuli is highly desired. In the present study, 3D conductive scaffolds were prepared by employing a biocompatible conductive polymer, ie, poly(3,4-ethylenedioxythiophene) poly (4-styrene sulfonate) (PEDOT:PSS), in the optimized nanocomposite of gelatin and bioactive glass. For in vitro analysis, adult human mesenchymal stem cells were seeded in the scaffolds. Material characterizations using hydrogen-1 nuclear magnetic resonance, in vitro degradation, as well as thermal and mechanical analysis showed that …

Microfluidic Generated Egf-Gradients Induce Chemokinesis Of Transplantable Retinal Progenitor Cells Via The Jak/Stat And Pi3kinase Signaling Pathways., Uchenna J. Unachukwu, Moira Sauane, Maribel Vazquez, Stephen Redenti

Publications and Research

A growing number of studies are evaluating retinal progenitor cell (RPC) transplantation as an approach to repair retinal degeneration and restore visual function. To advance cell-replacement strategies for a practical retinal therapy, it is important to define the molecular and biochemical mechanisms guiding RPC motility. We have analyzed RPC expression of the epidermal growth factor receptor (EGFR) and evaluated whether exposure to epidermal growth factor (EGF) can coordinate motogenic activity in vitro. Using Boyden chamber analysis as an initial high-throughput screen, we determined that RPC motility was optimally stimulated by EGF concentrations in the range of 20-400 ng/ml, with decreased …

Temperature-Dependent Dielectric And Thermal Properties Of Whey Protein Gel And Mashed Potato, Jiajia Chen, Krishnamoorthy Pitchai, Sohan Birla, Ricardo Gonzalez, David Jones, Jeyamkondan Subbiah

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Temperature-dependent dielectric properties (dielectric constant and dielectric loss factor) and thermal properties (thermal conductivity and specific heat capacity) of whey protein gel and mashed potato were measured from -20°C to 100°C. A dielectric properties measurement system and a multipoint temperature calibration protocol were developed. The system consists of an impedance analyzer, a high-temperature coaxial cable, a high-temperature coaxial probe, a micro-climatic chamber and a metal sample holder. Calibrations at two temperatures (25°C and 85°C) were sufficient to accurately measure the dielectric properties of foods from frozen to hot temperatures. Both dielectric constant and dielectric loss factor rapidly increased from -20°C …

2013 Fall Engr333 Project Final Report, 2013 Fall Engr333

ENGR 333

During the fall of 2013, the Engineering 333 class was asked the question, “what would it take for Calvin College to operate a biofuel vehicle from campus resources?” The three primary considerations included:

• Determining the optimal biofuel feedstock in terms of availability, transportation, and processing.
• Selecting a biofuel vehicle for conversion or purchase to operate on the selected feedstock.
• Designing the infrastructure and process required for operating the selected biofuel vehicle. The design and research described below proposes an environmentally sustainable and cost-effective method for integrating a biofuel vehicle into Calvin’s existing infrastructure.

Interactions Of Peptide Triazole Thiols With Env Gp120 Induce Irreversible Breakdown And Inactivation Of Hiv-1 Virions, Arangassery Bastian, Mark Contarino, Lauren D. Bailey, Rachna Aneja, Diogo Rodrigo Magalhaes Moreira, Kevin Freedman, Karyn Mcfadden, Caitlin Duffy, Ali Emileh

Dartmouth Scholarship

Background: We examined the underlying mechanism of action of the peptide triazole thiol, KR13 that has been shown previously to specifically bind gp120, block cell receptor site interactions and potently inhibit HIV-1 infectivity.

Results: KR13, the sulfhydryl blocked KR13b and its parent non-sulfhydryl peptide triazole, HNG156, induced gp120 shedding but only KR13 induced p24 capsid protein release. The resulting virion post virolysis had an altered morphology, contained no gp120, but retained gp41 that bound to neutralizing gp41 antibodies. Remarkably, HIV-1 p24 release by KR13 was inhibited by enfuvirtide, which blocks formation of the gp41 6-helix bundle during membrane fusion, while …

The Design And Validation Of A Computational Rigid Body Model For Study Of The Radial Head, Cassandra Woodcock

Theses and Dissertations

Rigid body modeling has historically been used to study various features of the elbow joint including both physical and computational models. Computational modeling provides an inexpensive, easily customizable, and effective method by which to predict and investigate the response of a physiological system to in vivo stresses and applied perturbations. Utilizing computer topography scans of a cadaveric elbow, a virtual representation of the joint was created using the commercially available MIMICS(TM) and SolidWorks(TM) software packages. Accurate 3D articular surfaces, ligamentous constraints, and joint contact parameters dictated motion. The model was validated against two cadaveric studies performed by Chanlalit et al. …

Localization Of Auditory Spatial Targets In Sighted And Blind Subjects, Richard Nuckols

Theses and Dissertations

This research was designed to investigate the fundamental nature in which blind people utilize audible cues to attend to their surroundings. Knowledge on how blind people respond to external spatial stimuli is expected to assist in development of better tools for helping people with visual disabilities navigate their environment. There was also interest in determining how blind people compare to sighted people in auditory localization tasks. The ability of sighted individuals, blindfolded individuals, and blind individuals in localizing spatial auditory targets was assessed. An acoustic display board allowed the researcher to provide multiple sound presentations to the subjects. The subjects’ …

Examination Of The Effect Of Different Training Metrics On Performance Of A Minimally Invasive Surgery Transfer Task, Cristofer Madera

Theses and Dissertations

The purpose of this experiment was to determine if there existed techniques to more efficiently train prospective surgeons the skills necessary to capably perform minimally invasive surgical procedures. Also, we wanted to know if trainees could be pushed to cognitively define a laparoscopic environment with a novel hand-eye relationship. To explore these questions, a simulation was setup wherein subjects would perform a laparoscopic transfer task and receive active feedback during training. Different subjects would receive different metrics as feedback and a comparison would be made between subjects with respect to standard metrics. Results of this experiment show that all subjects …

2013 Fall Engr333 Student Seminar Presentation, Claire Philippi, Karl Bratt, Mike Houtman, Brandon Koster

ENGR 333

File for student presentation, given by students in the Fall 2013 class of ENGR333.

Stability Of Silk And Collagen Protein Materials In Space, Xiao Hu, Waseem K. Raja, Bo An, Olena Tokareva, Peggy Cebe, David L. Kaplan

College of Science & Mathematics Departmental Research

Collagen and silk materials, in neat forms and as silica composites, were flown for 18 months on the International Space Station [Materials International Space Station Experiment (MISSE)-6] to assess the impact of space radiation on structure and function. As natural biomaterials, the impact of the space environment on films of these proteins was investigated to understand fundamental changes in structure and function related to the future utility in materials and medicine in space environments. About 15% of the film surfaces were etched by heavy ionizing particles such as atomic oxygen, the major component of the low-Earth orbit space environment. Unexpectedly, …

2013 Fall Engr333 Vehicle Poster, 2013 Fall Engr333

ENGR 333

Waste vegetable oil (WVO) was chosen by the class as the best fuel source for the Calvin Biofuel Vehicle Project. The class then considered vehicle options and selected a lawnmower to be powered by WVO.

2013 Fall Engr333 Fuel And Facilities Poster, 2013 Fall Engr333

ENGR 333

The objective of the project was to answer the question: “What would it take for Calvin College to operate a biofuel vehicle from campus resources.” The class split into 3 teams:

• Fuel/Feedstock
• Facilities/Infrastructure
• Vehicle

Patient-Specific Modeling Of Adult Acquired Flatfoot Deformity Before And After Surgery, Edward Meade Spratley

Theses and Dissertations

The use of computational modeling is an increasingly commonplace technique for the investigation of biomechanics in intact and pathological musculoskeletal systems. Moreover, given the robust and repeatable nature of computer simulation and the prevalence of software techniques for accurate 3-D reconstructions of tissues, the predictive power of these models has increased dramatically. However, there are no patient-specific kinematic models whose function is dictated solely by physiologic soft-tissue constraints, articular shape and contact, and without idealized joint approximations. Moreover, very few models have attempted to predict surgical effects combined with postoperative validation of those predictions. Given this, it is not surprising …

Mechanical Properties Of Hydrated Acoustically Sensitive Alginate-Based Microcapsules Confined In A Microfluidic Device As A Function Of Size And Composition, Maryam Mobed-Miremadi, Mallika Keralapura, Tiffany Fong, Rogel Camba

Bioengineering

Understanding the mechanical properties of alginate-based microcapsules according to size and chemical composition allows researchers to zero in on the treatment and methods required to engineer optimized implantable alginate-based artificial cells for chemotherapy. Cross-linked medium viscosity alginate capsules ranging from 1.1% (w/v)-1.8% (w/v) in composition and 200 μm-1200 μm in size, encapsulating ultrasound contrast agents and blue dextran were compressed within a 40 μm high polydimethylsiloxane microfluidic device and subsequently examined using 2D microscopy for strain deformation aimed at the calculation of poisson ratios and volume loss postcompression. Results indicate a decrease in Poisson ratio as a function of alginate …

Fabrication And In Vivo Thrombogenecity Testing Of Nitric Oxide Generating Artificial Lungs, Kagya Amoako, Patrick Montoya, Terry C. Major, Ahmed B. Suhaib, Hitesh Handa, David O. Brant, Mark E. Meyerhoff, Robert H. Bartlett, Keith E. Cook

Mechanical and Industrial Engineering Faculty Publications

Hollow fiber artificial lungs are increasingly being used for long-term applications. However, clot formation limits their use to 1–2 weeks. This study investigated the effect of nitric oxide generating (NOgen) hollow fibers on artificial lung thrombogenicity. Silicone hollow fibers were fabricated to incorporate 50 nm copper particles as a catalyst for NO generation from the blood. Fibers with and without (control) these particles were incorporated into artificial lungs with a 0.1 m2 surface area and inserted in circuits coated tip-to-tip with the NOgen material. Circuits (N = 5/each) were attached to rabbits in a pumpless, arterio-venous configuration and run for …

Layered Long Term Co-Culture Of Hepatocytes And Endothelial Cells On A Transwell Membrane: Toward Engineering The Liver Sinusoid, Young Bok (Abraham) Kang, Siddhartha Rawat, Joseph Cirillo, Michael Bouchard, Hongseok (Moses) Noh

Faculty Publications - Biomedical, Mechanical, and Civil Engineering

This paper presents a novel liver model that mimics the liver sinusoid where most liver activities occur. A key aspect of our current liver model is a layered co-culture of primary rat hepatocytes (PRHs) and primary rat liver sinusoidal endothelial cells (LSECs) or bovine aortic endothelial cells (BAECs) on a transwell membrane. When a layered co-culture was attempted with a thin matrigel layer placed between hepatocytes and endothelial cells to mimic the Space of Disse, the cells did not form completely separated monolayers. However, when hepatocytes and endothelial cells were cultured on the opposite sides of a transwell membrane, PRHs …

Image Registration Of Ex-Vivo Mri To Sparsely Sectioned Histology Of Hippocampal And Neocortical Temporal Lobe Specimens., Maged Goubran, Cathie Crukley, Sandrine De Ribaupierre, Terence M Peters, Ali R Khan

Robarts Imaging Publications

Intractable or drug-resistant epilepsy occurs in up to 30% of epilepsy patients, with many of these patients undergoing surgical excision of the affected brain region to achieve seizure control. Recent magnetic resonance imaging (MRI) sequences and analysis techniques have the potential to detect abnormalities not identified with diagnostic MRI protocols. Prospective studies involving pre-operative imaging and collection of surgically-resected tissue provide a unique opportunity for verification and tuning of these image analysis techniques, since direct comparison can be made against histopathology, and can lead to better prediction of surgical outcomes and potentially less invasive procedures. To carry out MRI and …

Raman Spectroscopic Investigation Of Chondroitinase Abc Treatment After Spinal Cord Injury In An Organotypic Model, Shane Ruberto

Theses - ALL

This study investigated (1) the ability of an organotypic model of spinal cord injury (SCI) to recapitulate significant pathobiological events of in vivo SCI from a Raman spectroscopic perspective, and (2) the Raman spectroscopic effects of chondroitinase ABC (cABC) treatment on said model of SCI. Tissue from mouse spinal cords was excised, sectioned, and placed into culture, before being systematically injured to induce trauma. Cultures with and without cABC treatment were assessed using Raman spectroscopy at varying times post-injury. We demonstrate that Raman spectral phenomena characteristic of SCI can be observed using an organotypic model. By comparing these phenomena with …