Biomedical Engineering and Bioengineering Commons^™

A Novel Fmri Paradigm Suggests That Pedaling-Related Brain Activation Is Altered After Stroke, Nutta-On Promjunyakul, Brian D. Schmit, Sheila M. Schindler-Ivens

Physical Therapy Faculty Research and Publications

The purpose of this study was to examine the feasibility of using functional magnetic resonance imaging (fMRI) to measure pedaling-related brain activation in individuals with stroke and age-matched controls. We also sought to identify stroke-related changes in brain activation associated with pedaling. Fourteen stroke and 12 control subjects were asked to pedal a custom, MRI-compatible device during fMRI. Subjects also performed lower limb tapping to localize brain regions involved in lower limb movement. All stroke and control subjects were able to pedal while positioned for fMRI. Two control subjects were withdrawn due to claustrophobia, and one control data set was …

Technical Note: Phantom Study To Evaluate The Dose And Image Quality Effects Of A Computed Tomography Organ-Based Tube Current Modulation Technique, Diksha Gandhi, Dominic J. Crotty, Grant M. Stevens, Taly Gilat Schmidt

Biomedical Engineering Faculty Research and Publications

Purpose

This technical note quantifies the dose and image quality performance of a clinically available organ-dose-based tube current modulation (ODM) technique, using experimental and simulation phantom studies. The investigated ODM implementation reduces the tube current for the anterior source positions, without increasing current for posterior positions, although such an approach was also evaluated for comparison.

Methods

Axial CT scans at 120 kV were performed on head and chest phantoms on an ODM-equipped scanner (Optima CT660, GE Healthcare, Chalfont St. Giles, England). Dosimeters quantified dose to breast, lung, heart, spine, eye lens, and brain regions for ODM and 3D-modulation (SmartmA) settings. …

Critical Changes In Cortical Neuronal Interactions In Anesthetized And Awake Rats, Anthony G. Hudetz, Jeannette A. Vizuete, Siveshigan Pillay, Kristina M. Ropella

Biomedical Engineering Faculty Research and Publications

Background: Neuronal interactions are fundamental for information processing, cognition, and consciousness. Anesthetics reduce spontaneous cortical activity; however, neuronal reactivity to sensory stimuli is often preserved or augmented. How sensory stimulus–related neuronal interactions change under anesthesia has not been elucidated. In this study, the authors investigated the visual stimulus–related cortical neuronal interactions during stepwise emergence from desflurane anesthesia.

Methods: Parallel spike trains were recorded with 64-contact extracellular microelectrode arrays from the primary visual cortex of chronically instrumented, unrestrained rats (N = 6) at 8, 6, 4, and 2% desflurane anesthesia and wakefulness. Light flashes were delivered to the retina …

Large-Scale Spatiotemporal Spike Patterning Consistent With Wave Propagation In Motor Cortex, Kazutaka Takahashi, Sanggyun Kim, Todd P. Coleman, Kevin A. Brown, Aaron J. Suminski, Matthew D. Best, Nicholas G. Hatsopoulos

Biomedical Engineering Faculty Research and Publications

Aggregate signals in cortex are known to be spatiotemporally organized as propagating waves across the cortical surface, but it remains unclear whether the same is true for spiking activity in individual neurons. Furthermore, the functional interactions between cortical neurons are well documented but their spatial arrangement on the cortical surface has been largely ignored. Here we use a functional network analysis to demonstrate that a subset of motor cortical neurons in non-human primates spatially coordinate their spiking activity in a manner that closely matches wave propagation measured in the beta oscillatory band of the local field potential. We also demonstrate …

Evaluation Of Pediatric Manual Wheelchair Mobility Using Advanced Biomechanical Methods, Brooke A. Slavens, Alyssa J. Schnorenberg, Christine M. Aurit, Adam Graf, Joseph J. Krzak, Kathryn Reiners, Lawrence C. Vogel, Gerald F. Harris

Biomedical Engineering Faculty Research and Publications

There is minimal research of upper extremity joint dynamics during pediatric wheelchair mobility despite the large number of children using manual wheelchairs. Special concern arises with the pediatric population, particularly in regard to the longer duration of wheelchair use, joint integrity, participation and community integration, and transitional care into adulthood. This study seeks to provide evaluation methods for characterizing the biomechanics of wheelchair use by children with spinal cord injury (SCI). Twelve subjects with SCI underwent motion analysis while they propelled their wheelchair at a self-selected speed and propulsion pattern. Upper extremity joint kinematics, forces, and moments were computed using …

Experimental Comparison Of Empirical Material Decomposition Methods For Spectral Ct, Kevin C. Zimmerman, Taly Gilat Schmidt

Biomedical Engineering Faculty Research and Publications

Material composition can be estimated from spectral information acquired using photon counting x-ray detectors with pulse height analysis. Non-ideal effects in photon counting x-ray detectors such as charge-sharing, k-escape, and pulse-pileup distort the detected spectrum, which can cause material decomposition errors. This work compared the performance of two empirical decomposition methods: a neural network estimator and a linearized maximum likelihood estimator with correction (A-table method). The two investigated methods differ in how they model the nonlinear relationship between the spectral measurements and material decomposition estimates. The bias and standard deviation of material decomposition estimates were compared for the two methods, …

In Vivo Detection Of Hyperoxia-Induced Pulmonary Endothelial Cell Death Using 99mTc-Duramycin, Said H. Audi, Elizabeth R. Jacobs, Ming Zhao, David L. Roerig, Steven T. Haworth, Anne V. Clough

Biomedical Engineering Faculty Research and Publications

Introduction

^99mTc-duramycin, DU, is a SPECT biomarker of tissue injury identifying cell death. The objective of this study is to investigate the potential of DU imaging to quantify capillary endothelial cell death in rat lung injury resulting from hyperoxia exposure as a model of acute lung injury.

Methods

Rats were exposed to room air (normoxic) or > 98% O₂ for 48 or 60 hours. DU was injected i.v. in anesthetized rats, scintigraphy images were acquired at steady-state, and lung DU uptake was quantified from the images. Post-mortem, the lungs were removed for histological studies. Sequential lung sections were immunostained …

The Synthesis And Characterization Of Dual-Modified Carboxymethylcellulose For Bioadhesive Applications, Fabrice Bernard

Dissertations and Theses

Reparative medical techniques, in conjunction with existing and emerging tissue adherents and sealants, offer practicing physicians a wide variety of tools to improve the functionality, performance, and safety of surgical interventions. Carboxymethylcellulose (CMC) is a plant-derived polymer that is cytocompatible, biocompatible, biodegradable, and inexpensive. The need for a non-toxic but strongly adherent material motivated the development of an injectable bioadhesive system containing CMC modified with functional methacrylate and aldehyde groups that could potentially be used as an annulus fibrosus sealant or as a supplement to existing wound closure materials. After modification, the polymer was characterized via NMR spectroscopy, Schiff’s base …

Assessment Of Injection Behavior Of Commercially-Available Bone Bsms For Subchondroplasty Procedures, Dinely A. Colon

Dissertations and Theses

Subchondroplasty is a procedure that utilized bone substitutes materials (BSMs) or bone cement to correct bone defects in the subchondral bone. The two main materials used to compose BSMs are poly-methyl-methacrylate (PMMA) and calcium phosphate cement (CaP). Currently, there is no optimal bone material substitute in the market that can provide both the adequate mechanical support and the right viscosity to reach the affected area in the subchondral bone. In addition, there is also no established parameter for their proper use, based on the defect size and location. PMMA possesses comparable mechanical properties to bone (i.e. 96 MPa in compressive …

Morphology Of Brain Sulci Trabeculae And Its Effect On Brain During Impacts, Sharlin Anwar

Dissertations and Theses

Traumatic brain injury (TBI) is an intracranial injury caused by direct contact or non-contact head impacts to the brain. TBI is a major problem that accounts for high incidents of hospitalizations each year. Thus, it is important to understand and predict the occurrence of TBI in an impact. It has been shown that the subarachnoid space (SAS) trabeculae play an important role in damping the effect of an impact, thus reducing the injuries. However, the influence of sulci parameters and the sulci trabeculae in TBI due to impact is unexplored. Studies have shown that inclusion of sulci in brain models …

Programmable Dna Delivery To Cells Using Bioreducible Layer-By-Layer (Lbl) Polyelectrolyte Thin Films, Maria Muniz

Wayne State University Theses

Bioreducible, layer-by-layer (LbL) polyelectrolyte films show great promise for use in biomedical implant and gene-delivery applications. These nanometer-scale thin films can easily be coated onto a variety of implantable surfaces or devices. To achieve proof of concept, HEK-293, NIH/3T3, RAW, and MC3T3 cells were transfected using plasmid DNA with the green fluorescent protein reporter gene (GFP-DNA). In order to optimize transfection, a number of polyelectrolytes and biological components were systematically incorporated into the two similar basic LbL structures. Based on our previous degradation assays, it is shown that cellular interactions in vitro can break down the layers of the thin …

Assessment Of Temporal And Spatial Alterations In Spinal Glial Reactivityand The Extent Of Cervical Spinal Axonal Injury In The Rat After Blast Overpressure, Heena S. Purkait

Wayne State University Theses

Blast induced neurotrauma (BINT) is the signature wound of veterans returning from various military operations. A substantial percentage of Operations Enduring Freedom (OEF) and Iraqi Freedom (OIF) veterans have reported to experience ongoing or new pain following their military service. Head (58%) and back (55%) have been the high prevailing locations of pain in these returning OIF and OEF veterans and the underlying pathomechanism of these conditions is yet to be understood. In the context of blast overpressure induced pathological changes, the fundamental question that still needs to be addressed is whether there are any underlying cellular injury changes the …

Using The Symmetry Of False Matches To Solve The Correspondence Problem, Cherlyn J. Ng, Bart Farell

Biomedical and Chemical Engineering - All Scholarship

Veridical stereoscopic depth depends on matching corresponding image points. This requires solving the stereo correspondence problem: how are true matches distinguished from false ones? Conventional algorithms select true matches on the basis of feature detection [what do you mean by ‘feature detection’ here? Is there some more specific term?] and adherence to natural statistics. They reject false matches as noise. We propose here an alternative that uses the signals present in false matches to delineate the true solution. When visualized in a Keplerian array, binocular matches are symmetrically reflected about an axis that is a potential solution. Properties such as …

Computer Aided Detection Of Oral Lesions On Ct Images, Shaikat Mahmood Galib

Masters Theses

"Oral lesions are important findings on computed tomography images. They are difficult to detect on CT images because of low contrast, arbitrary orientation of objects, complicated topology and lack of clear lines indicating lesions. In this thesis, a fully automatic method to detect oral lesions from dental CT images is proposed to identify (1) Closed boundary lesions and (2) Bone deformation lesions. Two algorithms were developed to recognize these two types of lesions, which cover most of the lesion types that can be found on CT images. The results were validated using a dataset of 52 patients. Using non training …

Selective Laser Sintering Of Bioactive Glass Scaffolds And Their Biological Assessment For Bone Repair, Krishna C. R. Kolan

Doctoral Dissertations

"Bone scaffold fabrication using powder-bed based additive manufacturing techniques, like the selective laser sintering (SLS) process, provides control over pore interconnectivity, pore geometry, and the overall shape of the scaffold, which aids in repairing different regions of the bone. The main objectives of this dissertation were to develop bioactive glass (BG) scaffolds using the SLS process and evaluate the scaffolds for their effectiveness in bone repair both in vitro and in vivo. 13-93 glass, a silicate based BG, and 13-93B3 glass, a borate based BG, are designed to accelerate the body's natural ability to heal itself and are used …

Healing Of Bone Defects In A Rodent Calvarial Defect Model Using Strong Porous Bioactive Glass (13-93) Scaffolds, Yinan Lin

Masters Theses

"The main objective of this project was to evaluate the capacity of strong porous silicate (13-93) bioactive glass scaffolds prepared by a robocasting technique to regenerate bone and stimulate angiogenesis in a rat calvarial defect model. The scaffolds were created with the same grid-like microstructure but in a variety of formulations: (i) as-fabricated, (ii) pretreated in an aqueous phosphate solution to convert the glass surface to hydroxyapatite, (iii) loaded with bone morphogenetic protein-2 (BMP2) (1 µg per scaffold), and (iv) doped with copper (0.4-2.0 wt. % CuO). When compared to the as-fabricated scaffolds, the pretreated scaffolds enhanced bone regeneration at …

Vitamin D Receptor And 1Α, 25-Dihydroxyvitamin D3 Mediated Regulation Of Δnp63Α, Hill Tremayne Natasha

Browse all Theses and Dissertations

1alpha, 25-dihydroxyvitamin D3 (VD3), the ligand for the Vitamin D Receptor (VDR), functions to both inhibit cell growth and promote cell survival. High-dose VD3 is being utilized as a cancer preventive therapy for melanoma, breast and colorectal cancers, without a complete understanding of VD3/VDR signaling. DeltaNp63alpha, considered to be a proto-oncogene, is overexpressed in non-melanoma skin cancers (NMSCs), induces VDR gene expression and promotes keratinocyte proliferation, and may serve to exacerbate non-melanoma skin cancer. The objective of this dissertation was to determine whether VDR/VD3 signaling promotes keratinocyte proliferation by up-regulating DeltaNp63alpha. I showed that VDR increases DeltaNp63alpha expression at both …

Left Ventricle Volume Reconstruction To Minimize Scanning Time: Slice-Fitting Method, Prateek Kalra

Browse all Theses and Dissertations

Assessment of left ventricle volume is usually done for diagnosis and prognosis of heart diseases. Slice-summation method is a standard method used to compute left ventricle volume where region of interest from several short axis (SA) slices are added. There are some limitations to this method, however. It requires short-axis slices to be taken parallel to the mitral valve plane from the base to apex. Moreover, scanning several short-axis slices is a tedious and time consuming process especially for studies that require several hundreds datasets. There are some existing methods to reconstruct left ventricle volume but most of them depend …

Diffuse Optical Measurements Of Head And Neck Tumor Hemodynamics For Early Prediction Of Chemo-Radiation Therapy Outcomes, Lixin Dong

Theses and Dissertations--Biomedical Engineering

Chemo-radiation therapy is a principal modality for the treatment of head and neck cancers, and its efficacy depends on the interaction of tumor oxygen with free radicals. In this study, we adopted a novel hybrid diffuse optical instrument combining a commercial frequency-domain tissue oximeter (Imagent) and a custom-made diffuse correlation spectroscopy (DCS) flowmeter, which allowed for simultaneous measurements of tumor blood flow and blood oxygenation. Using this hybrid instrument we continually measured tumor hemodynamic responses to chemo-radiation therapy over the treatment period of 7 weeks. We also explored monitoring dynamic tumor hemodynamic changes during radiation delivery. Blood flow data analysis …

The Effect Of Cholesterol On The Osteoblast Responsiveness To Hydrodynamic Pressure Stimulation, Kristen Lough

Theses and Dissertations--Biomedical Engineering

Hypercholesterolemia is a risk factor for osteoporosis but the underlying mechanism is unknown. Previous evidence suggests that osteoporosis results from an impaired regulation of osteoblasts by fluid pressure fluctuations in the bone matrix. Recently, our laboratory showed that enhanced cholesterol in the cell membrane, due to hypercholesterolemia, alters leukocyte mechanosensitivity. We predict a similar link between osteoblasts and hypercholesterolemia leading to osteoporosis. Specifically, we hypothesize that extracellular cholesterol modifies the osteoblast sensitivity to pressure. MC3T3-E1 cells were exposed to hydrodynamic pressures regimes (mean=40mmHg, amplitude=0-20mmHg, frequency=1Hz) for 1-12 hours. To assess the impact of membrane cholesterol enrichment, cells were pre-treated with …