Engineering Commons^™

P&O, Arezoo Eshraghi

AREZOO ESHRAGHI

No abstract provided.

کارگاه اصول نگارش مقالات علمی 1, Dr Alireza Zolfaghari

Dr Alireza Zolfaghari

No abstract provided.

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 …

Under-Sampled Reconstruction Techniques For Accelerated Magnetic Resonance Imaging, Mohammad H. Kayvanrad

Electronic Thesis and Dissertation Repository

Due to physical and biological constraints and requirements on the minimum resolution and SNR, the acquisition time is relatively long in magnetic resonance imaging (MRI). Consequently, a limited number of pulse sequences can be run in a clinical MRI session because of constraints on the total acquisition time due to patient comfort and cost considerations. Therefore, it is strongly desired to reduce the acquisition time without compromising the reconstruction quality. This thesis concerns under-sampled reconstruction techniques for acceleration of MRI acquisitions, i.e., parallel imaging and compressed sensing.

While compressed sensing MRI reconstructions are commonly regularized by penalizing the decimated wavelet …

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

Biological Systems Engineering: Papers and 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 …

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 Development Of A New Dry Powder Inhaler, Xi Zhang

Electronic Thesis and Dissertation Repository

A new dry powder inhaler (DPI) for respiratory drug delivery was developed. This novel device is characterized by a micro-dose, passive delivery and multiple doses individually sealed in one replaceable disk. The micro-dose delivery system uses only a small amount of excipient, such as 2-3mg lactose, thereby improving the drug delivery efficiency. The passive delivery method eliminates the need for coordination between breath and device actuation such as the pressure metered dose inhaler (pMDI). Finally, 14 doses on a disk reduce the need to frequently change dosage disks. In addition, each dose is effectively protected by a blister package to …

Production Of Lignin-Based Phenolic Resins Using De-Polymerized Kraft Lignin And Process Optimization, Homaira Siddiqui

Electronic Thesis and Dissertation Repository

Commercialization of Lignin-based phenol formaldehyde resins (LPF) has been limited due to the increase in curing temperatures and decrease in adhesive strength of LPF compared to conventional phenolic resins. Lignin depolymerization can increase the reactivity of lignin; however, the effect of lignin molecular weight on curing performance of LPF resins has yet to be investigated. This research work examined the optimization of synthesis parameters including percent substitution of phenol with lignin, formaldehyde- to-phenol ratio (F/P), and Mw of lignin to reduce the curing temperature and increase the adhesive strength of LPF. DSC analysis indicated that lignin with Mw ~1200g/mol resulted …

New Technology And Techniques For Needle-Based Magnetic Resonance Image-Guided Prostate Focal Therapy, Jeremy Cepek

Electronic Thesis and Dissertation Repository

The most common diagnosis of prostate cancer is that of localized disease, and unfortunately the optimal type of treatment for these men is not yet certain. Magnetic resonance image (MRI)-guided focal laser ablation (FLA) therapy is a promising potential treatment option for select men with localized prostate cancer, and may result in fewer side effects than whole-gland therapies, while still achieving oncologic control. The objective of this thesis was to develop methods of accurately guiding needles to the prostate within the bore of a clinical MRI scanner for MRI-guided FLA therapy.

To achieve this goal, a mechatronic needle guidance system …

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 …

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 …

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

Faculty Scholarship for the College of Science & Mathematics

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, …

Systematic Genomic Identification Of Colorectal Cancer Genes Delineating Advanced From Early Clinical Stage, Patrick Flaherty

Patrick Flaherty

Cdi-Type Ii: Collaborative Research: Cyber Enhancement Of Spatial Cognition For The Visually Impaired, Nicholas Giudice

University of Maine Office of Research Administration: Grant Reports

Wayfinding is an essential capability for any person who wishes to have an independent life-style. It requires successful execution of several tasks including navigation and object and place recognition, all of which necessitate accurate assessment of the surrounding environment. For a visually-impaired person these tasks may be exceedingly difficult to accomplish and there are risks associated with failure in any of these. Guide dogs and white canes are widely used for the purpose of navigation and environment sensing, respectively. The former, however, has costly and often prohibitive training requirements, while the latter can only provide cues about obstacles in one's …

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 …

Biomimetic Poly(Ester Amide) Biomaterials For Vascular Tissue Engineering, Darryl K. Knight

Electronic Thesis and Dissertation Repository

The focus of this research was to develop a biomimetic, degradable vascular scaffold that could be considered as part of a tissue-engineered vascular graft strategy. A family of degradable poly(ester amide)s (PEAs) derived from naturally occurring α-amino acids, aliphatic diols and diacids were synthesized to yield PEAs with glass transition temperatures below physiologic temperature ensuring their pliability. Tri-functional amino acids l-lysine or l-aspartic acid were incorporated into the polymer backbone yielding complementary functional handles for subsequent conjugation of growth factors. Higher molecular weight PEAs were obtained using an interfacial polycondensation technique compared with a solution polymerization approach.

Human coronary artery …

Characteristics Of Glass Ionomer Cements Composed Of Glass Powders In Cao-Sro-Zno-Sio2 System Prepared By Two Different Synthetic Routes, Ill Yong Kim, Chikara Ohtsuki, Aisling Coughlan, Lana Placek, Anthony W. Wren, Mark R. Towler

Chemical and Biochemical Engineering Faculty Research & Creative Works

Glass ionomer cements (GICs) are composed of an acid degradable glass, polyacrylic acid and water. Sol-gel processing to prepare the glass phase has certain advantages, such as the ability to employ lower synthesis temperatures than melt quenching and glasses that are reported to have higher purity. A previous study reported the effects of glass synthesis route on GIC fabrication. However, in that study, the sol-gel derived glass exhibited a reduced concentration of cations. This study investigates increasing the cation content of a sol-gel derived glass, 12CaO·4SrO·36ZnO·48SiO₂ (molar ratio) by heating before aging to reduce dissolution of cations. This glass …

The Advancement Of Bacterial Cellulose As A Bone And Vascular Scaffolds, Ryan Lee Hammonds

Doctoral Dissertations

Bacterial cellulose (BC) is a natural hydrogel made of nanofibers. This material has been used in commercial products, including wound dressings. BC can be modified and optimized for improved performance in multiple applications. This work will focus on producing and characterizing resorbable cellulose, a composite for bone applications, and a composite for a synthetic venous valve leaflet.

BC can be produced and modified to perform as a degradable tissue scaffold. This is achieved by an oxidation procedure after the initial production and purification of native BC. A material characterization of oxidized BC was performed to identify the changes in properties …

Analysis, Segmentation And Prediction Of Knee Cartilage Using Statistical Shape Models, Joseph Michael Johnson

Doctoral Dissertations

Osteoarthritis (OA) of the knee is one of the leading causes of chronic disability (along with the hip). Due to rising healthcare costs associated with OA, it is important to fully understand the disease and how it progresses in the knee. One symptom of knee OA is the degeneration of cartilage in the articulating knee. The cartilage pad plays a major role in painting the biomechanical picture of the knee. This work attempts to quantify the cartilage thickness of healthy male and female knees using statistical shape models (SSMs) for a deep knee bend activity. Additionally, novel cartilage segmentation from …

Reconstruction Of Patient-Specific Bone Models From X-Ray Radiography, Hatem Amin Abdel Fattah El Dakhakhni

Doctoral Dissertations

The availability of a patient‐specific bone model has become an increasingly invaluable addition to orthopedic case evaluation and planning [1]. Utilized within a wide range of specialized visualization and analysis tools, such models provide unprecedented wealth of bone shape information previously unattainable using traditional radiographic imaging [2]. In this work, a novel bone reconstruction method from two or more x‐ray images is described. This method is superior to previous attempts in terms of accuracy and repeatability. The new technique accurately models the radiological scene in a way that eliminates the need for expensive multi‐planar radiographic imaging systems. It is also …

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 …

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 …

Depleted Energy Charge And Increased Pulmonary Endothelial Permeability Induced By Mitochondrial Complex I Inhibition Are Mitigated By Coenzyme Q1 In The Isolated Perfused Rat Lung, Robert D. Bongard, Ke Yan, Raymond G. Hoffmann, Said H. Audi, Xiao Zhang, Brian J. Lindemer, Mary I. Townsley, Marilyn P. Merker

Biomedical Engineering Faculty Research and Publications

Mitochondrial dysfunction is associated with various forms of lung injury and disease that also involve alterations in pulmonary endothelial permeability, but the relationship, if any, between the two is not well understood. This question was addressed by perfusing isolated intact rat lung with a buffered physiological saline solution in the absence or presence of the mitochondrial complex I inhibitor rotenone (20 μM). Compared to control, rotenone depressed whole lung tissue ATP from 5.66±0.46 (SEM) to 2.34±0.15 µmol·g⁻¹ dry lung, with concomitant increases in the ADP:ATP and AMP:ATP ratios. Rotenone also increased lung perfusate lactate (from 12.36±1.64 to 38.62±3.14 µmol·15 …

Extracting The Structure And Conformations Of Biological Entities From Large Datasets, Ali Dashti

Theses and Dissertations

In biology, structure determines function, which often proceeds via changes in conformation. Efficient means for determining structure exist, but mapping conformations continue to present a serious challenge. Single-particles approaches, such as cryogenic electron microscopy (cryo-EM) and emerging "diffract & destroy" X-ray techniques are, in principle, ideally positioned to overcome these challenges. But the algorithmic ability to extract information from large heterogeneous datasets consisting of "unsorted" snapshots - each emanating from an unknown orientation of an object in an unknown conformation - remains elusive.

It is the objective of this thesis to describe and validate a powerful suite of manifold-based algorithms …

Patient-Oriented Evidence-Based Treatment Decision Support System (Treatquest®) For Lung Cancer, Danqing Hu

Theses and Dissertations

Involving patients in healthcare decisions makes a significant and enduring difference to healthcare outcomes. One challenge for patients is the lack of evidence-based information and tools to support their decision making. Although patients have access to significant information through internet and other sources, it is not personalized for their specific situation. This dissertation attempts to help patients acquire evidence-based information relevant to their own situation, so they can make a more informed decision in co-operation with their physicians. Lung cancer has been selected as a focus for this study because lung cancer presents very complex decision making situation and is …

Electrotransfer Of Single-Stranded Or Double-Stranded Dna Induces Complete Regression Of Palpable B16.F10 Mouse Melanomas, Loree Heller, Vesba Todorovic, Maja Cemazar

Bioelectrics Publications

Enhanced tumor delivery of plasmid DNA with electric pulses in vivo has been confirmed in many preclinical models. Intratumor electrotransfer of plasmids encoding therapeutic molecules has reached Phase II clinical trials. In multiple preclinical studies, a reduction in tumor growth, increased survival or complete tumor regression have been observed in control groups in which vector or backbone plasmid DNA electrotransfer was performed. This study explores factors that could produce this antitumor effect. The specific electrotransfer pulse protocol employed significantly potentiated the regression. Tumor regression was observed after delivery of single-stranded or double-stranded DNA with or without CpG motifs in both …

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 …

Identification Of Novel Genes Regulating Elastic Fiber Formation Through Expression Profiling Analysis Of Elastogenic Models, Erin Sproul

All Dissertations

Background: Particularly important to the mechanical performance of native arterial blood vessels is elastin, an extracellular matrix (ECM) protein deposited by VSMCs in the form of elastic fibers, arranged in concentric lamellae in the media of the vessel wall. In addition to serving as major structural elements of arterial walls, providing extensibility and elastic recoil, elastic fibers also influence vascular cell behaviors. For these reasons tissue engineers are attempting to exploit elastic fiber biology to enhance vascular graft design and patency. Therefore, developing a greater understanding of the molecular mechanisms of elastogenesis may offer opportunities to control elastogenesis in tissue …