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Biomedical Engineering and Bioengineering

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Articles 8221 - 8250 of 11466

Full-Text Articles in Engineering

Enhancing The Engineering Curriculum: Defining Discovery Learning At Marquette University, Jay R. Goldberg, Mark L. Nagurka Oct 2012

Enhancing The Engineering Curriculum: Defining Discovery Learning At Marquette University, Jay R. Goldberg, Mark L. Nagurka

Biomedical Engineering Faculty Research and Publications

This paper summarizes the results of our investigation into the feasibility of increasing the level of discovery learning in the College of Engineering (COE) at Marquette University. We review the education literature, document examples of discovery learning currently practiced in the COE and other schools, and propose a Marquette COE-specific definition of discovery learn-ing. Based on our assessment of the benefits, costs, and tradeoffs associated with increasing the level of discovery learning, we pre-sent several recommendations and identify resources required for implementation. These recommendations may be helpful in enhancing engineering education at other schools.


Subnanosecond Exposure Systems For Biological Studies, Jongbong Nah Oct 2012

Subnanosecond Exposure Systems For Biological Studies, Jongbong Nah

Electrical & Computer Engineering Theses & Dissertations

The research of bioelectrics has expanded to subnanosecond pulse region and entered a new domain of biophysics of cell interaction with ultra-short and intense electric fields. As subnanosecond pulses may be delivered by antennas to the human body and is very attractive to the medical community, the study of subnanosecond pulse effects calls for exposure systems for both cells and tissues. Two systems were designed in the scope of this thesis, used for cells and tissues respectively. The exposure system designed for cell exposure is a cuvette consisting of two parallel aluminum gaps. This cuvette is placed in a coaxial …


Functional Integration In The Cortical Neuronal Network Of Conscious And Anesthetized Animals, Jeannette A. Vizuete Oct 2012

Functional Integration In The Cortical Neuronal Network Of Conscious And Anesthetized Animals, Jeannette A. Vizuete

Dissertations (1934 -)

General anesthesia consists of amnesia, analgesia, areflexia and unconsciousness. How anesthetics suppress consciousness has been a mystery for more than one and a half centuries.

The overall goal of my research has been to determine the neural correlates of anesthetic-induced loss of consciousness. I hypothesized that anesthetics induce unconsciousness by interfering with the functional connectivity of neuronal networks of the brain and consequently, reducing the brain's capacity for information processing. To test this hypothesis, I performed experiments in which neuronal spiking activity was measured with chronically implanted microelectrode arrays in the visual cortex of freely-moving rats during wakefulness and at …


Stem Cell Based Tissue Engineering And Regenerative Medicine: A Review Focusing On Adult Stem Cells, Jordan Greenberg, Veronica R. Fortino, Daniel Pelaez, Herman S. Cheung Oct 2012

Stem Cell Based Tissue Engineering And Regenerative Medicine: A Review Focusing On Adult Stem Cells, Jordan Greenberg, Veronica R. Fortino, Daniel Pelaez, Herman S. Cheung

Biology Faculty Articles

Tissue engineering has emerged as a field that attempts to harness the bodies' own developmental and repair features to treat diseases and illnesses. Many of these illnesses are caused by necrosis or loss of functionality of complete organs or specific cell types. Early discoveries in embryonic stem cells fueled a wave of research that led to claims about possibly regenerating nonfunctioning organs. Although we are still far away from being able to grow functional organs in a Petri dish, the field continues to progress forward, and new clinical trials have been approved for using both embryonic and adult stem cell …


Biomechanical Evaluation Of An Optical System For Quantitative Human Motion Analysis, Jeffrey D. Kertis Oct 2012

Biomechanical Evaluation Of An Optical System For Quantitative Human Motion Analysis, Jeffrey D. Kertis

Master's Theses (2009 -)

An eight-camera Optitrack motion capture system was evaluated by performing static, linear dynamic, and angular dynamic calibrations using marker distances associated with upper and lower extremity gait and wheelchair models. Data were analyzed to determine accuracy and resolution within a defined capture volume using a standard Cartesian reference system. Two additional cameras along with AMASS and Visual3D (C-Motion, Inc., Germantown, MD) biomechanical modeling software were used to determine joint kinematics at the pelvis, hip, knee, and ankle of ten control subjects (mean age 21.5 ± 1.65 years). The same data were processed through Nexus (Vicon Motion Systems, Oxford, England) modeling …


Biomechanical Model Of Pediatric Upper Extremity Dynamics During Wheelchair Mobility, Alyssa J. Paul Oct 2012

Biomechanical Model Of Pediatric Upper Extremity Dynamics During Wheelchair Mobility, Alyssa J. Paul

Master's Theses (2009 -)

Biomechanical analysis has been used by many to evaluate upper extremity (UE) motion during human movement, including during the use of assistive devices such as crutches and walkers. However, few studies have been conducted to examine the upper extremity kinetics during wheelchair mobility, specifically within the pediatric population. In 2000, 90% of wheelchair users (1.5 million people) in the United States were manual wheelchair users, requiring the use of their upper body to maneuver the wheelchair as well as perform other activities of daily living. Among children under the age of 18, the wheelchair was the most used assistive mobility …


Development And Performance Of A Sparsity-Exploiting Algorithm For Few-View Single Photon Emission Computed Tomogrpahy (Spect) Reconstruction, Paul Arthur Wolf Oct 2012

Development And Performance Of A Sparsity-Exploiting Algorithm For Few-View Single Photon Emission Computed Tomogrpahy (Spect) Reconstruction, Paul Arthur Wolf

Master's Theses (2009 -)

Single Photon Emission Computed Tomography (SPECT) provides noninvasive images of the distribution of radiotracer molecules. Dynamic Single Photon Emission Computed Tomography provides information about tracer uptake and washout from a series of time-sequence images. Stationary ring-like multi-camera systems are being developed to provide rapid dynamic acquisitions with high temporal sampling. Reducing the number of cameras reduces the cost of such systems but also reduces the number of views acquired, limiting the angular sampling of the system. Novel few-view image reconstruction methods may be beneficial and are being investigated for the application of dynamic SPECT. A sparsity-exploiting algorithm intended for few-view …


Three-Dimensional Biomechanical Model Of Wrist Dynamics During Tasks Of Daily Living, Patrick Roscher Oct 2012

Three-Dimensional Biomechanical Model Of Wrist Dynamics During Tasks Of Daily Living, Patrick Roscher

Master's Theses (2009 -)

An understanding of wrist dynamics during functional movements is required to better diagnose and treat wrist injury and disease. Currently, there is a lack of upper extremity (UE) models that combine both the motions and resulting forces that occur in the wrist during daily activities. The purpose of this study is to create a three-dimensional (3D) model of the upper extremity that describes kinematics and wrist kinetics during functional activities. A model of this type could benefit clinical diagnosis, treatment, and follow-up care of orthopaedic and neurological disorders of the wrist. The created dynamic wrist model was used to test …


Conference Program, Engineering Conferences International Sep 2012

Conference Program, Engineering Conferences International

Harnessing The Materials Genome: Accelerated Materials Development via Computational and Experimental Tools

highlighted titles are available online documents.


Characterization Of Xylan Utilization And Discovery Of A New Endoxylanase In Thermoanaerobacterium Saccharolyticum Through Targeted Gene Deletions, Kara K. Podkaminer, Adam M. Guss, Heather L. Trajano, David A. Hogsett, Lee R. Lynd Sep 2012

Characterization Of Xylan Utilization And Discovery Of A New Endoxylanase In Thermoanaerobacterium Saccharolyticum Through Targeted Gene Deletions, Kara K. Podkaminer, Adam M. Guss, Heather L. Trajano, David A. Hogsett, Lee R. Lynd

Dartmouth Scholarship

The economical production of fuels and commodity chemicals from lignocellulose requires the utilization of both the cellulose and hemicellulose fractions. Xylanase enzymes allow greater utilization of hemicellulose while also increasing cellulose hydrolysis. Recent metabolic engineering efforts have resulted in a strain of Thermoanaerobacterium saccharolyticum that can convert C5 and C6 sugars, as well as insoluble xylan, into ethanol at high yield. To better understand the process of xylan solubilization in this organism, a series of targeted deletions were constructed in the homoethanologenic T. saccharolyticum strain M0355 to characterize xylan hydrolysis and xylose utilization in this organism. While the deletion of …


Soft Microenvironments Promote The Early Neurogenic Differentiation But Not Self-Renewal Of Human Pluripotent Stem Cells, Albert Keung, Prashanth Asuri, Sanjay Kumar, David Schaffer Sep 2012

Soft Microenvironments Promote The Early Neurogenic Differentiation But Not Self-Renewal Of Human Pluripotent Stem Cells, Albert Keung, Prashanth Asuri, Sanjay Kumar, David Schaffer

Bioengineering

Human pluripotent stem cells (hPSCs) are of great interest in biology and medicine due to their ability to self-renew and differentiate into any adult or fetal cell type. Important efforts have identified biochemical factors, signaling pathways, and transcriptional networks that regulate hPSC biology. However, recent work investigating the effect of biophysical cues on mammalian cells and adult stem cells suggests that the mechanical properties of the microenvironment, such as stiffness, may also regulate hPSC behavior. While several studies have explored this mechanoregulation in mouse embryonic stem cells (mESCs), it has been challenging to extrapolate these findings and thereby explore their …


Whole-Word Recognition From Articulatory Movements For Silent Speech Interfaces, Jun Wang, Ashok Samal, Jordan R. Green, Frank Rudzicz Sep 2012

Whole-Word Recognition From Articulatory Movements For Silent Speech Interfaces, Jun Wang, Ashok Samal, Jordan R. Green, Frank Rudzicz

Department of Special Education and Communication Disorders: Faculty Publications

Articulation-based silent speech interfaces convert silently produced speech movements into audible words. These systems are still in their experimental stages, but have significant potential for facilitating oral communication in persons with laryngectomy or speech impairments. In this paper, we report the result of a novel, real-time algorithm that recognizes whole-words based on articulatory movements. This approach differs from prior work that has focused primarily on phoneme-level recognition based on articulatory features. On average, our algorithm missed 1.93 words in a sequence of twenty-five words with an average latency of 0.79 seconds for each word prediction using a data set of …


Adhesion And Proliferation Of Red Fluorescent U87 Cells In A Mirco-Incubator, Rebecca L. Jensen Sep 2012

Adhesion And Proliferation Of Red Fluorescent U87 Cells In A Mirco-Incubator, Rebecca L. Jensen

Undergraduate Research Posters 2012

Availability of bone forming osteoblast cells from genetically modified green fluorescing protein (GFP) expressing mouse opens up the possibility of carrying out live cell imaging of the cells as they adhere, migrate and proliferate on nano-texture modified opaque metallic surfaces. Cells inoculated at a density of 200 cells/mm2 proliferated 131% over a one week period.


A Low Cost Motion Analysis System Based On Kinect, Jonathan Michael Cardinale, Tracy N. Jennemann, Vitaliy Sinyuk, Sam Kenji Yokoyama Sep 2012

A Low Cost Motion Analysis System Based On Kinect, Jonathan Michael Cardinale, Tracy N. Jennemann, Vitaliy Sinyuk, Sam Kenji Yokoyama

Undergraduate Research Posters 2012

The project focused on the validation of using the Kinect sensor to build a low cost motion analysis system for physical therapy and rehabilitation, and the identification of the types of the motions that cannot be captured well by the Kinect sensor and are in need of inertial sensors.


Image-Based Quantification Of Benzoporphyrin Derivative Uptake, Localization, And Photobleaching In 3d Tumor Models, For Optimization Of Pdt Parameters, Michael D. Glidden, Jonathan P. Celli, Iqbal Massodi, Imran Rizvi, Brian Pogue, Tayyaba Hasan Sep 2012

Image-Based Quantification Of Benzoporphyrin Derivative Uptake, Localization, And Photobleaching In 3d Tumor Models, For Optimization Of Pdt Parameters, Michael D. Glidden, Jonathan P. Celli, Iqbal Massodi, Imran Rizvi, Brian Pogue, Tayyaba Hasan

Dartmouth Scholarship

Photodynamic therapy (PDT) is a light-based treatment modality in which wavelength specific activation of a photosensitizer (PS) generates cytotoxic response in the irradiated region. PDT response is critically dependent on several parameters including light dose, PS dose, uptake time, fluence rate, and the mode of light delivery. While the systematic optimization of these treatment parameters can be complex, it also provides multiple avenues for en- hancement of PDT efficacy under diverse treatment conditions, provided that a rational framework is established to quantify the impact of parameter selection upon treatment re- sponse. Here we present a theranostic technique, combining the inherent …


Developing Novel Prognostic Biomarkers For Multivariate Fracture Risk Prediction Algorithms, Ernest K. Poku, Mark R. Towler, Niamh M. Cummins, Jeff D. Newman Sep 2012

Developing Novel Prognostic Biomarkers For Multivariate Fracture Risk Prediction Algorithms, Ernest K. Poku, Mark R. Towler, Niamh M. Cummins, Jeff D. Newman

Chemical and Biochemical Engineering Faculty Research & Creative Works

Multivariate prediction algorithms such as FRAX® and QFracture Scores provide an opportunity for new prognostic biomarkers to be developed and incorporated, potentially leading to better fracture prediction. As more research is conducted into these novel biomarkers, a number of factors need to be considered for their successful development for inclusion in these algorithms. In this review, we describe two well-known multivariate prediction algorithms for osteoporosis fracture risk applicable to the UK population, FRAX and QFracture Scores, and comment on the current prognostic tools available for fracture risk; dual X-ray assessment, quantitative ultrasonography, and genomic/biochemical markers. We also highlight the factors …


Hydrodynamic Focused Passive Separation Under Continuous Flow In A Microfluidic Chip, Jad Kanbar Sep 2012

Hydrodynamic Focused Passive Separation Under Continuous Flow In A Microfluidic Chip, Jad Kanbar

Master's Theses

A continuous flow, passive separation device was designed using an equivalent circuit to create variable flow rates for hydrodynamic focusing to drain channels and collection outlets. By varying the diameter of the sample inlet connection into the reservoir, the particle position was influenced significantly, which enabled desired separations. Additionally it was noted that the relative, horizontal position of the inlet also had a significant influence on particle position within the device. A dimensionless number, the Characteristic Sample Inlet, was developed to relate geometric properties of the inlet reservoir to downstream particle distribution. It was found that a 2:1 ratio between …


Investigation Of A New Material For Heart Valve Tissue Engineering, Claire Brougham, Gerard Cooney, Thomas Flanagan, Stefan Jockenhoevel, Fergal O'Brien Sep 2012

Investigation Of A New Material For Heart Valve Tissue Engineering, Claire Brougham, Gerard Cooney, Thomas Flanagan, Stefan Jockenhoevel, Fergal O'Brien

Conference Papers

No abstract provided.


Creep Evaluation Of (Orthotic) Cast Materials During Simulated Clubfoot Correction, T. L. Cohen, H. Altiok, Sergey Tarima, P. A. Smith, Gerald F. Harris Sep 2012

Creep Evaluation Of (Orthotic) Cast Materials During Simulated Clubfoot Correction, T. L. Cohen, H. Altiok, Sergey Tarima, P. A. Smith, Gerald F. Harris

Biomedical Engineering Faculty Research and Publications

The Ponseti method is a widely accepted and highly successful conservative treatment of pediatric clubfoot that relies on weekly manipulations and cast applications. However, the material behavior of the cast in the Ponseti technique has not been investigated. The current study sought to characterize the ability of two standard casting materials to maintain the Ponseti corrected foot position by evaluating creep response. A dynamic cast testing device (DCTD) was built to simulate a typical pediatric clubfoot. Semi-rigid fiberglass and rigid fiberglass casting materials were applied to the device, and the rotational creep was measured at various constant torques. The movement …


Responding To Dangerous Accidents Among The Elderly: A Fall Detection Device With Zigbee-Based Positioning, Michael R. Putnam Sep 2012

Responding To Dangerous Accidents Among The Elderly: A Fall Detection Device With Zigbee-Based Positioning, Michael R. Putnam

Master's Theses

The following paper describes a fall detection and activity monitoring system with position detection based on Zigbee transceivers.The main objective is to reduce the time taken for emergency personnel to respond to falls among the elderly. Especially when the victim is unconscious or delirious, position tracking reduces location determination time within a busy hospital or nursing home environment and facilitates immediate treatment. Reduced response times correlate to decreased morbidity and mortality rates. Background is provided on the major wireless network advances currently deployed in a healthcare setting for asset and personnel tracking, etiology of falls, and several methods of detecting …


Chronically Inadequate Sleep Results In Abnormal Bone Formation And Abnormal Bone Marrow In Rats, Carol A. Everson, Anne E. Folley, Jeffrey M. Toth Sep 2012

Chronically Inadequate Sleep Results In Abnormal Bone Formation And Abnormal Bone Marrow In Rats, Carol A. Everson, Anne E. Folley, Jeffrey M. Toth

Biomedical Engineering Faculty Research and Publications

Insufficient sleep over long durations of the lifespan is believed to adversely affect proper development and healthful aging, although how this might become manifested is unknown. In the present study, rats were repeatedly sleep-restricted during 72 days to permit maladaptations to evolve, thereby permitting study. Densitometric and histomorphometric analyses were performed on harvested bone. In sleep-restricted rats, bone lined by osteoid was reduced 45-fold and osteoid thickness was decreased, compared with controls. This corresponded to a decrease in osteoblast number and activity. The percentage of bone lined by osteoclasts did not differ from that of controls. Plasma concentrations of an …


Quaternary Ammonium Silane-Functionalized, Methacrylate Resin Composition With Antimicrobial Activities And Self-Repair Potential, Shi-Qiang Gong, Li-Na Niu, Lisa K. Kemp, Cynthia K.Y. Yiu, Heonjune Ryou, Yi-Pin Qi, John D. Blizzard, Sergey Nikonov, Martha G. Brackett, Regina L.W. Messer, Christine D. Wu, Jing Mao, L. Bryan Brister, Frederick A. Rueggeberg, Dwayne D. Arola, David H. Pashley, Franklin R. Tay Sep 2012

Quaternary Ammonium Silane-Functionalized, Methacrylate Resin Composition With Antimicrobial Activities And Self-Repair Potential, Shi-Qiang Gong, Li-Na Niu, Lisa K. Kemp, Cynthia K.Y. Yiu, Heonjune Ryou, Yi-Pin Qi, John D. Blizzard, Sergey Nikonov, Martha G. Brackett, Regina L.W. Messer, Christine D. Wu, Jing Mao, L. Bryan Brister, Frederick A. Rueggeberg, Dwayne D. Arola, David H. Pashley, Franklin R. Tay

Faculty Publications

The design of antimicrobial polymers to address healthcare issues and minimize environmental problems is an important endeavor with both fundamental and practical implications. Quaternary ammonium silane-functionalized methacrylate (QAMS) represents an example of antimicrobial macromonomers synthesized by a sol–gel chemical route; these compounds possess flexible Si–O–Si bonds. In present work, a partially hydrolyzed QAMS co-polymerized with 2,2-[4(2-hydroxy 3-methacryloxypropoxy)-phenyl]propane is introduced. This methacrylate resin was shown to possess desirable mechanical properties with both a high degree of conversion and minimal polymerization shrinkage. The kill-on-contact microbiocidal activities of this resin were demonstrated using single-species biofilms of Streptococcus mutans (ATCC 36558), Actinomyces naeslundii (ATCC …


Phase Transitions Of Nanoemulsions Using Ultrasound: Experimental Observations, Ram Singh, Ghaleb A. Husseini, William G. Pitt Sep 2012

Phase Transitions Of Nanoemulsions Using Ultrasound: Experimental Observations, Ram Singh, Ghaleb A. Husseini, William G. Pitt

Faculty Publications

The ultrasound-induced transformation of perfluorocarbon liquids to gases is of interest in the area of drug and gene delivery. In this study, three independent parameters (temperature, size, and perfluorocarbon species) were selected to investigate the effects of 476-kHz and 20-kHz ultrasound on nanoemulsion phase transition. Two levels of each factor (low and high) were considered at each frequency. The acoustic intensities at gas bubble formation and at the onset of inertial cavitation were recorded and subsequently correlated with the acoustic parameters. Experimental data showed that low frequencies are more effective in forming and collapsing a bubble. Additionally, as the size …


Role Of Glutathione In Lung Retention Of 99mtc-Hexamethylpropyleneamine Oxime In Two Unique Rat Models Of Hyperoxic Lung Injury, Said H. Audi, David L. Roerig, Steven Thomas Haworth, Anne V. Clough Aug 2012

Role Of Glutathione In Lung Retention Of 99mtc-Hexamethylpropyleneamine Oxime In Two Unique Rat Models Of Hyperoxic Lung Injury, Said H. Audi, David L. Roerig, Steven Thomas Haworth, Anne V. Clough

Biomedical Engineering Faculty Research and Publications

Rat exposure to 60% O2 for 7 days (hyper-60) or to >95% O2 for 2 days followed by a 24-hour in room air (hyper-95R) confers susceptibility or tolerance, respectively, of the otherwise lethal effects of subsequent exposure to 100% O2. The objective of this study was to determine if lung retention of the radiopharmaceutical agent 99mTc-HMPAO (hexamethylpropyleneamine oxime) is differentially altered in hyper-60 and hyper-95R rats. Tissue retention of HMPAO is dependent on intracellular content of the antioxidant glutathione (GSH) and mitochondrial function. HMPAO was injected i.v. in anesthetized rats and planar images were acquired. …


Mineralization Potential Of Electrospun Pdo-Hydroxyapatite-Fibrinogen Blended Scaffolds, Isaac A. Rodriguez, Parthasarathy A. Madurantakam, Jennifer M. Mccool, Scott A. Sell, Hu Yang, Peter C. Moon, Gary L. Bowlin Aug 2012

Mineralization Potential Of Electrospun Pdo-Hydroxyapatite-Fibrinogen Blended Scaffolds, Isaac A. Rodriguez, Parthasarathy A. Madurantakam, Jennifer M. Mccool, Scott A. Sell, Hu Yang, Peter C. Moon, Gary L. Bowlin

Chemical and Biochemical Engineering Faculty Research & Creative Works

The current bone autograft procedure for cleft palate repair presents several disadvantages such as limited availability, additional invasive surgery, and donor site morbidity. The present preliminary study evaluates the mineralization potential of electrospun polydioxanone:nano-hydroxyapatite: fibrinogen (PDO: nHA: Fg) blended scaffolds in different simulated body fluids (SBF). Scaffolds were fabricated by blending PDO: nHA: Fg in the following percent by weight ratios: 100: 0: 0, 50: 25: 25, 50: 50: 0, 50: 0: 50, 0: 0: 100, and 0: 50: 50. Samples were immersed in (conventional (c), revised (r), ionic (i), and modified (m)) SBF for 5 and 14 days to …


A Study Towards Development Of An Automated Haptic User Interface (Ahui) For Individuals Who Are Blind Or Visually Impaired, Ravi Rastogi Aug 2012

A Study Towards Development Of An Automated Haptic User Interface (Ahui) For Individuals Who Are Blind Or Visually Impaired, Ravi Rastogi

Theses and Dissertations

An increasing amount of information content used in schools, work and everyday living is being presented in graphical form, creating accessibility challenges for individuals who are blind or visually impaired, especially in dynamic environments, such as over the internet. Refreshable haptic displays that can interact with computers can be used to access such information tactually. Main focus of this study was the development of specialized computer applications allowing users to actively compensate for the inherent issues of haptics when exploring visual diagrams as compared to vision, which we hypothesized, would improve the usability of such devices. An intuitive zooming algorithm …


Piezoelectric Probes And Their Capacity To Monitor Time Varying Viscosity, Eman Ahmed Aug 2012

Piezoelectric Probes And Their Capacity To Monitor Time Varying Viscosity, Eman Ahmed

Theses and Dissertations

Real-time, bedside observation of patient clotting is essential in various surgeries in the operating room (OR), but specifically during cardiac surgeries. The objective of this thesis is to design and test a new piezoelectric device that can be used for viscoelasticity measurement with time as a Point of Care (POC) test. Slow turnaround times (TAT) of current methods to monitor blood viscoelastic changes in patients have led to excessive bleeding and the need for blood transfusions in many situations (Despotis et al, 1997). This study shows that the phase shift produced by a resonator sensor can be related to the …


A Digital X-Ray Tomosynthesis Coupled Near Infrared Spectral Tomography System For Dual-Modality Breast Imaging, Venkataramanan Krishnaswamy, Kelly E. Michaelsen, Brian W. Pogue, Steven P. Poplack, Ian Shaw, Ken Defrietas, Ken Brooks, Keith D. Paulsen Aug 2012

A Digital X-Ray Tomosynthesis Coupled Near Infrared Spectral Tomography System For Dual-Modality Breast Imaging, Venkataramanan Krishnaswamy, Kelly E. Michaelsen, Brian W. Pogue, Steven P. Poplack, Ian Shaw, Ken Defrietas, Ken Brooks, Keith D. Paulsen

Dartmouth Scholarship

A Near Infrared Spectral Tomography (NIRST) system has been developed and integrated into a commercial Digital Breast Tomosynthesis (DBT) scanner to allow structural and functional imaging of breast in vivo. The NIRST instrument uses an 8-wavelength continuous wave (CW) laser-based scanning source assembly and a 75-element silicon photodiode solid-state detector panel to produce dense spectral and spatial projection data from which spectrally constrained 3D tomographic images of tissue chromophores are produced. Integration of the optical imaging system into the DBT scanner allows direct co-registration of the optical and DBT images, while also facilitating the synergistic use of x-ray contrast as …


Integrated Fiber Electrospinning: Creating Spatially Complex Electrospun Scaffolds With Minimal Delamination, Casey Grey Aug 2012

Integrated Fiber Electrospinning: Creating Spatially Complex Electrospun Scaffolds With Minimal Delamination, Casey Grey

Theses and Dissertations

Tissue engineering scaffolds come in many shapes and sizes, however, due to difficulty manufacturing the microstructure architecture required in tissue engineering, most scaffolds are architecturally non-dynamic in nature. Because the microstructural architecture of all biological tissues is inherently complicated, non-dynamic tissue engineering scaffolds tend to be a poor platform for tissue regeneration. The current method for manufacturing dynamic tissue engineering scaffolds involves electrospinning successive layers of different fibers, an approach that exhibits no fiber transition between layers and subsequent delamination problems. In this study we aim to address the design challenges of tissue engineering scaffolds through our novel integrated fiber …


Preparation And Characterization Of A Self-Crimp Side-By-Side Bicomponent Electrospun Material, Yang Han Aug 2012

Preparation And Characterization Of A Self-Crimp Side-By-Side Bicomponent Electrospun Material, Yang Han

Theses and Dissertations

Bicomponent composite fibers have been widely used in the textile industry and are gaining increasing attention on biomedical applications. In this research, polycaprolactone/poly (lactic acid) side-by-side bicomponent fibers were created for the application of a biodegradable scaffold. The side-by-side structure endowed the fiber with self-crimps when it was processed under certain conditions. This material was produced by electrospinning and collected on a high speed rotating mandrel to get highly oriented fibers. A mechanical stretch at the same direction was done followed by a wet heat treatment for polymer retraction. Crimped fibers were demonstrated by scanning electron microscopy. The quantitative porosity …