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Biomedical Engineering and Bioengineering Commons

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2013

Selected Works

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Articles 1 - 30 of 44

Full-Text Articles in Biomedical Engineering and Bioengineering

Comment On "Quadriceps Protects The Anterior Cruciate Ligament", Antonie J. Van Den Bogert Dec 2013

Comment On "Quadriceps Protects The Anterior Cruciate Ligament", Antonie J. Van Den Bogert

Antonie J. van den Bogert

No abstract provided.


Personal Navigation Via High-Resolution Gait-Corrected Inertial Measurement Units, Özkan Bebek, Michael A. Suster, Srihari Rajgopal, Michael J. Fu, Xuemei Huang, M. Cenk Çavu¸So˘Glu,, Darrin J. Young, Mehran Mehregany, Antonie J. Van Den Bogert, Carlos H. Mastrangelo Dec 2013

Personal Navigation Via High-Resolution Gait-Corrected Inertial Measurement Units, Özkan Bebek, Michael A. Suster, Srihari Rajgopal, Michael J. Fu, Xuemei Huang, M. Cenk Çavu¸So˘Glu,, Darrin J. Young, Mehran Mehregany, Antonie J. Van Den Bogert, Carlos H. Mastrangelo

Antonie J. van den Bogert

In this paper, a personal micronavigation system that uses high-resolution gait-corrected inertial measurement units is presented. The goal of this paper is to develop a navigation system that uses secondary inertial variables, such as velocity, to enable long-term precise navigation in the absence of Global Positioning System (GPS) and beacon signals. In this scheme, measured zerovelocity duration from the ground reaction sensors is used to reset the accumulated integration errors from accelerometers and gyroscopes in position calculation. With the described system, an average position error of 4 m is achieved at the end of half-hour walks.


Simulation Of Lower Limb Axial Arterial Length Change During Locomotion, Melissa D. Young, Matthew C. Streicher, Richard J. Beck, Antonie J. Van Den Bogert, Azita Tajaddini, Brian L. Davis Dec 2013

Simulation Of Lower Limb Axial Arterial Length Change During Locomotion, Melissa D. Young, Matthew C. Streicher, Richard J. Beck, Antonie J. Van Den Bogert, Azita Tajaddini, Brian L. Davis

Antonie J. van den Bogert

The effect of external forces on axial arterial wall mechanics has conventionally been regarded as secondary to hemodynamic influences. However, arteries are similar to muscles in terms of the manner in which they traverse joints, and their three-dimensional geometrical requirements for joint motion. This study considers axial arterial shortening and elongation due to motion of the lower extremity during gait, ascending stairs, and sitting-to-standing motion. Arterial length change was simulated by means of a graphics based anatomic and kinematic model of the lower extremity. This model estimated the axial shortening to be as much as 23% for the femoropopliteal arterial ...


The Biomechanical Role Of Scaffolds In Augmented Rotator Cuff Tendon Repairs, Amit Aurora, Jesse A. Mccarron, Antonie J. Van Den Bogert, Jorge E. Gatica, Joseph P. Iannotti, Kathleen A. Derwin Dec 2013

The Biomechanical Role Of Scaffolds In Augmented Rotator Cuff Tendon Repairs, Amit Aurora, Jesse A. Mccarron, Antonie J. Van Den Bogert, Jorge E. Gatica, Joseph P. Iannotti, Kathleen A. Derwin

Antonie J. van den Bogert

Background Scaffolds continue to be developed and used for rotator cuff repair augmentation; however, the appropriate scaffold material properties and/or surgical application techniques for achieving optimal biomechanical performance remains unknown. The objectives of the study were to simulate a previously validated spring-network model for clinically relevant scenarios to predict: (1) the manner in which changes to components of the repair influence the biomechanical performance of the repair and (2) the percent load carried by the scaffold augmentation component. Materials and methods The models were parametrically varied to simulate clinically relevant scenarios, namely, changes in tendon quality, altered surgical technique ...


An Analytical Model For Rotator Cuff Repairs, A. Aurora, Jorge E. Gatica, Antonie J. Van Den Bogert, J. A. Mccarron, Kathleen A. Derwin Dec 2013

An Analytical Model For Rotator Cuff Repairs, A. Aurora, Jorge E. Gatica, Antonie J. Van Den Bogert, J. A. Mccarron, Kathleen A. Derwin

Antonie J. van den Bogert

Background

Currently, natural and synthetic scaffolds are being explored as augmentation devices for rotator cuff repair. When used in this manner, these devices are believed to offer some degree of load sharing; however, no studies have quantified this effect. Furthermore, the manner in which loads on an augmented rotator cuff repair are distributed among the various components of the repair is not known, nor is the relative biomechanical importance of each component. The objectives of this study are to (1) develop quasi-static analytical models of simplified rotator cuff repairs, (2) validate the models, and (3) predict the degree of load ...


A Real-Time, 3-D Musculoskeletal Model For Dynamic Simulation Of Arm Movements, Edward K. Chadwick, Dimitra Blana, Antonie J. Van Den Bogert, Robert F. Kirsch Dec 2013

A Real-Time, 3-D Musculoskeletal Model For Dynamic Simulation Of Arm Movements, Edward K. Chadwick, Dimitra Blana, Antonie J. Van Den Bogert, Robert F. Kirsch

Antonie J. van den Bogert

Neuroprostheses can be used to restore movement of the upper limb in individuals with high-level spinal cord injury. Development and evaluation of command and control schemes for such devices typically require real-time, ldquopatient-in-the-looprdquo experimentation. A real-time, 3-D, musculoskeletal model of the upper limb has been developed for use in a simulation environment to allow such testing to be carried out noninvasively. The model provides real-time feedback of human arm dynamics that can be displayed to the user in a virtual reality environment. The model has a 3-DOF glenohumeral joint as well as elbow flexion/extension and pronation/supination and contains ...


Robotic Testing Of Proximal Tibio-Fibular Joint Kinematics For Measuring Instability Following Total Knee Arthroplasty, Wael K. Barsoum, Ho H. Lee, Trevor G. Murray, Robb Colbrunn, Alison K. Klika, S. Butler, Antonie J. Van Den Bogert Dec 2013

Robotic Testing Of Proximal Tibio-Fibular Joint Kinematics For Measuring Instability Following Total Knee Arthroplasty, Wael K. Barsoum, Ho H. Lee, Trevor G. Murray, Robb Colbrunn, Alison K. Klika, S. Butler, Antonie J. Van Den Bogert

Antonie J. van den Bogert

Pain secondary to instability in total knee arthroplasty (TKA) has been shown to be major cause of early failure. In this study, we focused on the effect of instability in TKA on the proximal tibio-fibular joint (PTFJ). We used a robotics model to compare the biomechanics of the PTFJ in the native knee, an appropriately balanced TKA, and an unbalanced TKA. The tibia (n = 5) was mounted to a six-degree-of-freedom force/torque sensor and the femur was moved by a robotic manipulator. Motion at the PTFJ was recorded with a high-resolution digital camera system. After establishing a neutral position, loading ...


Systematic Genomic Identification Of Colorectal Cancer Genes Delineating Advanced From Early Clinical Stage, Patrick Flaherty Dec 2013

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

Patrick Flaherty

Background: Colorectal cancer is the third leading cause of cancer deaths in the United States. The initial assessment of colorectal cancer involves clinical staging that takes into account the extent of primary tumor invasion, determining the number of lymph nodes with metastatic cancer and the identification of metastatic sites
in other organs. Advanced clinical stage indicates metastatic cancer, either in regional lymph nodes or in distant organs. While the genomic and genetic basis of colorectal cancer has been elucidated to some degree, less is known about the identity of specific cancer genes that are associated with advanced clinical stage and ...


Pre-Amplifiers For A 15-Tesla Magnetic Resonance Imager, Chin-Leong Lim, Peter Serano, Jerome L. Ackerman Nov 2013

Pre-Amplifiers For A 15-Tesla Magnetic Resonance Imager, Chin-Leong Lim, Peter Serano, Jerome L. Ackerman

Chin-Leong Lim

High-field magnetic resonance imagers (MRI) give better signal-to-noise ratio (SNR) and image contrast. However clinical MRIs are currently limited to 3 Tesla (T) magnetic field strength. To create an uncommon 15 T scanner for research use, we evaluated several low-cost, intended for wireless communication, GaAs enhancement-mode pseudomorphic high electron mobility transistors (ePHEMT) in the critical preamplifier slot. This paper reports the experimental results that were obtained at both module and system levels. When evaluated in our prototype 15 T scanner front-end’s preamplifier slot, the candidate devices’ sub 1dB noise figures enabled image SNR ~ 110 in a water phantom (test ...


Mammalian Cells Preferentially Internalize Hydrogel Nanodiscs Over Nanorods And Use Shape-Specific Uptake Mechanisms, Rachit Agarwal, Vikramjit Singh, Patrick Jurney, Li Shi, S. V. Sreenivasan, Krishnendu Roy Oct 2013

Mammalian Cells Preferentially Internalize Hydrogel Nanodiscs Over Nanorods And Use Shape-Specific Uptake Mechanisms, Rachit Agarwal, Vikramjit Singh, Patrick Jurney, Li Shi, S. V. Sreenivasan, Krishnendu Roy

Patrick Jurney

Size, surface charge, and material compositions are known to influence cell uptake of nanoparticles. However, the effect of particle geometry, i.e., the interplay between nanoscale shape and size, is less understood. Here we show that when shape is decoupled from volume, charge, and material composition, under typical in vitro conditions, mammalian epithelial and immune cells preferentially internalize disc-shaped, negatively charged hydrophilic nanoparticles of high aspect ratios compared with nanorods and lower aspect-ratio nanodiscs. Endothelial cells also prefer nanodiscs, however those of intermediate aspect ratio. Interestingly, unlike nanospheres, larger-sized hydrogel nanodiscs and nanorods are internalized more efficiently than their smallest ...


Biokinetic Mechanisms Linked With Musculoskeletal Health Disparities: Stochastic Models Applying Tikhonov's Theorem To Biomolecule Homeostasis., Asit K. Saha, Yu Liang, Sean S. Kohles Oct 2013

Biokinetic Mechanisms Linked With Musculoskeletal Health Disparities: Stochastic Models Applying Tikhonov's Theorem To Biomolecule Homeostasis., Asit K. Saha, Yu Liang, Sean S. Kohles

Sean S. Kohles

Multiscale technology and advanced mathematical models have been developed to control and characterize physicochemical interactions, respectively, enhancing cellular and molecular engineering progress. Ongoing tissue engineering development studies have provided experimental input for biokinetic models examining the influence of static or dynamic mechanical stimuli (Saha, A. K., and Kohles, S. S., 2010, “A Distinct Catabolic to Anabolic Threshold Due to Single-Cell Nanomechanical Stimulation in a Cartilage Biokinetics Model,” J. Nanotechnol. Eng. Med., 1(3) p. 031005; 2010, “Periodic Nanomechanical Stimulation in a Biokinetics Model Identifying Anabolic and Catabolic Pathways Associated With Cartilage Matrix Homeostasis,” J. Nanotechnol. Eng. Med., 1(4), p ...


Optical Acquisition And Polar Decomposition Of The Full-Field Deformation Gradient Tensor Within A Fracture Callus, Wangdo Kim, Sean S. Kohles Oct 2013

Optical Acquisition And Polar Decomposition Of The Full-Field Deformation Gradient Tensor Within A Fracture Callus, Wangdo Kim, Sean S. Kohles

Sean S. Kohles

Tracking tissue deformation is often hampered by material inhomogeneity, so local measurements tend to be insufficient thus lending to the necessity of full-field optical measurements. This study presents a novel approach to factoring heterogeneous deformation of soft and hard tissues in a fracture callus by introducing an anisotropic metric derived from the deformation gradient tensor (F). The deformation gradient tensor contains all the information available in a Green-Lagrange strain tensor, plus the rigid-body rotational components. A recent study [Bottlang et al., J. Biomech. 41(3), 2008] produced full-field strains within ovine fracture calluses acquired through the application of electronic speckle ...


Plasma Levels Of Polychlorinated Biphenyls, Non-Hodgkin Lymphoma, And Causation, Michael D. Freeman, Sean S. Kohles Oct 2013

Plasma Levels Of Polychlorinated Biphenyls, Non-Hodgkin Lymphoma, And Causation, Michael D. Freeman, Sean S. Kohles

Sean S. Kohles

Polychlorinated biphenyls (PCBs) are synthetic chlorinated hydrocarbons that have extensively polluted the environment and bioaccumulated in the food chain. PCBs have been deemed to be probable carcinogens by the Environmental Protection Agency, and exposure to high levels of PCBs has been consistently linked to increased risk of non-Hodgkin lymphoma (NHL). In the present article we present a forensic epidemiologic evaluation of the causal relationship between NHL and elevated PCB levels via application of the Bradford-Hill criteria. Included in the evaluation is a meta-analysis of the results of previously published case-control studies in order to assess the strength of association between ...


Prediction Of Growth Factor Effects On Engineered Cartilage Composition Using Deterministic And Stochastic Modeling, Sean S. Kohles, Asit K. Saha, J. (Jagannath) Mazumdar Oct 2013

Prediction Of Growth Factor Effects On Engineered Cartilage Composition Using Deterministic And Stochastic Modeling, Sean S. Kohles, Asit K. Saha, J. (Jagannath) Mazumdar

Sean S. Kohles

In the design of engineered tissues, guided balance of biomaterial degeneration with tissue synthesis offers refined control of construct development. The objective of this study was to develop a mathematical model that describes the steady state metabolism of extracellular matrix molecules (ECM: glycosaminoglycan and collagen) in an engineered cartilage construct taking into account localized environmental changes that may arise because of the application of growth factors. The variable effects of growth factors were incorporated in the form of random noise rather than the difference in rates of synthesis and catabolism. Thus, the frequency of ECM accumulation for each matrix molecule ...


Cytoskeletal Strains In Modeled Optohydrodynamically Stressed Healthy And Diseased Biological Cells, Sean S. Kohles, Yu Liang, Asit K. Saha Oct 2013

Cytoskeletal Strains In Modeled Optohydrodynamically Stressed Healthy And Diseased Biological Cells, Sean S. Kohles, Yu Liang, Asit K. Saha

Sean S. Kohles

Controlled external chemomechanical stimuli have been shown to influence cellular and tissue regeneration/degeneration, especially with regards to distinct disease sequelae or health maintenance. Recently, a unique three-dimensional stress state was mathematically derived to describe the experimental stresses applied to isolated living cells suspended in an optohydrodynamic trap (optical tweezers combined with microfluidics). These formulae were previously developed in two and three dimensions from the fundamental equations describing creeping flows past a suspended sphere. The objective of the current study is to determine the full-field cellular strain response due to the applied three-dimensional stress environment through a multiphysics computational simulation ...


Fgf2-Induced Effects On Transcriptome Associated With Regeneration Competence In Adult Human Fibroblasts, Sakthikumar Ambady, Olga Kashpur, David Lapointe, Elizabeth Ryder, Tanja Dominko Sep 2013

Fgf2-Induced Effects On Transcriptome Associated With Regeneration Competence In Adult Human Fibroblasts, Sakthikumar Ambady, Olga Kashpur, David Lapointe, Elizabeth Ryder, Tanja Dominko

Sakthikumar Ambady

Adult human fibroblasts grown in low oxygen and with FGF2 supplementation have the capacity to tip the healing outcome of skeletal muscle injury - by favoring regeneration response in vivo over scar formation. Here, we compare the transcriptomes of control adult human dermal fibroblasts and induced regeneration-competent (iRC) fibroblasts to identify transcriptional changes that may be related to their regeneration competence. RESULTS: We identified a unique gene-expression profile that characterizes FGF2-induced iRC fibroblast phenotype. Significantly differentially expressed genes due to FGF2 treatment were identified and analyzed to determine overrepresented Gene Ontology terms. Genes belonging to extracellular matrix components, adhesion molecules, matrix ...


Toward A Gpu-Accelerated Immersed Boundary Method For Wind Forecasting Over Complex Terrain, Rey Deleon, Kyle Felzien, Inanc Senocak Sep 2013

Toward A Gpu-Accelerated Immersed Boundary Method For Wind Forecasting Over Complex Terrain, Rey Deleon, Kyle Felzien, Inanc Senocak

Inanc Senocak

A short-term wind power forecasting capability can be a valuable tool in the renewable energy industry to address load-balancing issues that arise from intermittent wind fields. Although numerical weather prediction models have been used to forecast winds, their applicability to micro-scale atmospheric boundary layer flows and ability to predict wind speeds at turbine hub height with a desired accuracy is not clear. To address this issue, we develop a multi-GPU parallel flow solver to forecast winds over complex terrain at the micro-scale, where computational domain size can range from meters to several kilometers. In the solver, we adopt the immersed ...


Developing A Small-Footprint Bioengineering Program, Alisha Sarang-Sieminski, Debbie Chachra Sep 2013

Developing A Small-Footprint Bioengineering Program, Alisha Sarang-Sieminski, Debbie Chachra

Alisha L. Sarang-Sieminski

The field of bioengineering is rapidly changing and expanding to include not only more traditional bioengineering applications (e.g. device-focused areas such as prosthetics, imaging) but also more recent sub-fields and technologies(e.g. more biologically-focused areas such as those enabled by tissue engineering and microfluidics). This rapid change, coupled with the intrinsically interdisciplinary nature of bioengineering, presents a unique challenge to the developers of academic programs, as they need to both select relevant content and strike a balance between depth and breadth. We, the architects of the bioengineering program at the undergraduate-only Franklin W. Olin College of Engineering, which ...


Computational Design Optimization For Microfluidic Magnetophoresis, Brian Dennis Plouffe, Laura H. Lewis, Shashi Krishna Murthy Aug 2013

Computational Design Optimization For Microfluidic Magnetophoresis, Brian Dennis Plouffe, Laura H. Lewis, Shashi Krishna Murthy

Laura H. Lewis

Current macro- and microfluidic approaches for the isolation of mammalian cells are limited in both efficiency and purity. In order to design a robust platform for the enumeration of a target cell population, high collection efficiencies are required. Additionally, the ability to isolate pure populations with minimal biological perturbation and efficient off-chip recovery will enable subcellular analyses of these cells for applications in personalized medicine. Here, a rational design approach for a simple and efficient device that isolates target cell populations via magnetic tagging is presented. In this work, two magnetophoretic microfluidic device designs are described, with optimized dimensions and ...


Computational Design Optimization For Microfluidic Magnetophoresis, Brian Plouffe, Laura Lewis, Shashi Murthy Jul 2013

Computational Design Optimization For Microfluidic Magnetophoresis, Brian Plouffe, Laura Lewis, Shashi Murthy

Shashi K. Murthy

Current macro- and microfluidic approaches for the isolation of mammalian cells are limited in both efficiency and purity. In order to design a robust platform for the enumeration of a target cell population, high collection efficiencies are required. Additionally, the ability to isolate pure populations with minimal biological perturbation and efficient off-chip recovery will enable subcellular analyses of these cells for applications in personalized medicine. Here, a rational design approach for a simple and efficient device that isolates target cell populations via magnetic tagging is presented. In this work, two magnetophoretic microfluidic device designs are described, with optimized dimensions and ...


Development Of A Novel Handheld Device For Active Compensation Of Physiological Tremor, Abhijit Saxena Jul 2013

Development Of A Novel Handheld Device For Active Compensation Of Physiological Tremor, Abhijit Saxena

Abhijit Saxena

In microsurgery, the human hand imposes certain limitations in accurately positioning the tip of a device such as scalpel. Any errors in the motion of the hand make microsurgical procedures difficult and involuntary motions such as hand tremors can make some procedures significantly difficult to perform. This is particularly true in the case of vitreoretinal microsurgery. The most familiar source of involuntary motion is physiological tremor. Real-time compensation of tremor is, therefore, necessary to assist surgeons to precisely position and manipulate the tool-tip to accurately perform a microsurgery. In this thesis, a novel handheld device (AID) is described for compensation ...


Influence Of Van Der Waals Forces On Increasing The Strength And Toughness In Dynamic Fracture Of Nanofibre Networks: A Peridynamic Approach, Florin Bobaru Ph.D. Jul 2013

Influence Of Van Der Waals Forces On Increasing The Strength And Toughness In Dynamic Fracture Of Nanofibre Networks: A Peridynamic Approach, Florin Bobaru Ph.D.

Florin Bobaru Ph.D.

The peridynamic method is used here to analyse the effect of van der Waals forces on the mechanical behaviour and strength and toughness properties of three-dimensional nanofibre networks under imposed stretch deformation. The peridynamic formulation allows for a natural inclusion of long-range forces (such as van der Waals forces) by considering all interactions as ‘long-range’. We use van der Waals interactions only between different fibres and do not need to model individual atoms. Fracture is introduced at the microstructural (peridynamic bond) level for the microelastic type bonds, while van der Waals bonds can reform at any time. We conduct statistical ...


Nonlinear Strain Stiffening Is Not Sufficient To Explain How Far Cells Can Feel On Fibrous Protein Gels., Kristen Billiar, Mathilda Rudnicki, Heather Cirka, Maziar Aghvami, Edward Sander, Qi Wen Jul 2013

Nonlinear Strain Stiffening Is Not Sufficient To Explain How Far Cells Can Feel On Fibrous Protein Gels., Kristen Billiar, Mathilda Rudnicki, Heather Cirka, Maziar Aghvami, Edward Sander, Qi Wen

Kristen L. Billiar

Recent observations suggest that cells on fibrous extracellular matrix materials sense mechanical signals over much larger distances than they do on linearly elastic synthetic materials. In this work, we systematically investigate the distance fibroblasts can sense a rigid boundary through fibrous gels by quantifying the spread areas of human lung fibroblasts and 3T3 fibroblasts cultured on sloped collagen and fibrin gels. The cell areas gradually decrease as gel thickness increases from 0 to 150 μm, with characteristic sensing distances of >65 μm below fibrin and collagen gels, and spreading affected on gels as thick as 150 μm. These results demonstrate ...


Measuring The Mechanical Properties Of Living Cells Using Atomic Force Microscopy, Nancy Burnham, Gawain Thomas, Terri Camesano, Qi Wen Jun 2013

Measuring The Mechanical Properties Of Living Cells Using Atomic Force Microscopy, Nancy Burnham, Gawain Thomas, Terri Camesano, Qi Wen

Nancy A. Burnham

Mechanical properties of cells and extracellular matrix (ECM) play important roles in many biological processes including stem cell differentiation, tumor formation, and wound healing. Changes in stiffness of cells and ECM are often signs of changes in cell physiology or diseases in tissues. Hence, cell stiffness is an index to evaluate the status of cell cultures. Among the multitude of methods applied to measure the stiffness of cells and tissues, micro-indentation using an Atomic Force Microscope (AFM) provides a way to reliably measure the stiffness of living cells. This method has been widely applied to characterize the micro-scale stiffness for ...


Rvd: A Command-Line Program For Ultrasensitive Rare Single Nucleotide Variant Detection Using Targeted Next-Generation Dna Resequencing, Patrick Flaherty May 2013

Rvd: A Command-Line Program For Ultrasensitive Rare Single Nucleotide Variant Detection Using Targeted Next-Generation Dna Resequencing, Patrick Flaherty

Patrick Flaherty

Background: Rare single nucleotide variants play an important role in genetic diversity and heterogeneity of specific human disease. For example, an individual clinical sample can harbor rare mutations at minor frequencies. Genetic diversity within an individual clinical sample is oftentimes reflected in rare mutations. Therefore, detecting
rare variants prior to treatment may prove to be a useful predictor for therapeutic response. Current rare variant detection algorithms using next generation DNA sequencing are limited by inherent sequencing error rate and platform availability.
Findings: Here we describe an optimized implementation of a rare variant detection algorithm called RVD for use in targeted ...


Overcoming The Diffraction Limit Using Multiple Light Scattering In A Highly Disordered Medium, Youngwoon Choi, Taeseok Daniel Yang, Christopher Fang-Yen, Pilsung Kang, Kyoung Jin Lee, Ramachandra R. Dasari, Michael S. Feld, Wonshik Choi Apr 2013

Overcoming The Diffraction Limit Using Multiple Light Scattering In A Highly Disordered Medium, Youngwoon Choi, Taeseok Daniel Yang, Christopher Fang-Yen, Pilsung Kang, Kyoung Jin Lee, Ramachandra R. Dasari, Michael S. Feld, Wonshik Choi

Christopher Fang-Yen

We report that disordered media made of randomly distributed nanoparticles can be used to overcome the diffraction limit of a conventional imaging system. By developing a method to extract the original image information from the multiple scattering induced by the turbid media, we dramatically increase a numerical aperture of the imaging system. As a result, the resolution is enhanced by more than 5 times over the diffraction limit, and the field of view is extended over the physical area of the camera. Our technique lays the foundation to use a turbid medium as a far-field superlens.


Scanner-Free And Wide-Field Endoscopic Imaging By Using A Single Multimode Optical Fiber, Youngwoon Choi, Changhyeong Yoon, Moonseok Kim, Taeseok Daniel Yang, Christopher Fang-Yen, Ramchandra R. Dasari, Kyoung Jin Lee, Wonshik Choi Apr 2013

Scanner-Free And Wide-Field Endoscopic Imaging By Using A Single Multimode Optical Fiber, Youngwoon Choi, Changhyeong Yoon, Moonseok Kim, Taeseok Daniel Yang, Christopher Fang-Yen, Ramchandra R. Dasari, Kyoung Jin Lee, Wonshik Choi

Christopher Fang-Yen

A single multimode fiber is considered an ideal optical element for endoscopic imaging due to the possibility of direct image transmission via multiple spatial modes. However, the wave distortion induced by the mode dispersion has been a fundamental limitation. In this Letter, we propose a method for eliminating the effect of mode dispersion and therefore realize wide-field endoscopic imaging by using only a single multimode fiber with no scanner attached to the fiber. Our method will potentially revolutionize endoscopy in various fields encompassing medicine and industry.


Three-Dimensional Differential Interference Contrast Microscopy Using Synthetic Aperture Imaging, Moonseok Kim, Youngwoon Choi, Christopher Fang-Yen, Yongjin Sung, Kwanhyung Kim, Ramachandra R. Dasari, Michael S. Feld, Wonshik Choi Apr 2013

Three-Dimensional Differential Interference Contrast Microscopy Using Synthetic Aperture Imaging, Moonseok Kim, Youngwoon Choi, Christopher Fang-Yen, Yongjin Sung, Kwanhyung Kim, Ramachandra R. Dasari, Michael S. Feld, Wonshik Choi

Christopher Fang-Yen

We implement differential interference contrast (DIC) microscopy using high-speed synthetic aperture imaging that expands the passband of coherent imaging by a factor of 2.2. For an aperture synthesized coherent image, we apply for the numerical post-processing and obtain a high-contrast DIC image for arbitrary shearing direction and bias retardation. In addition, we obtain images at different depths without a scanning objective lens by numerically propagating the acquired coherent images. Our method achieves high-resolution and high-contrast 3-D DIC imaging of live biological cells. The proposed method will be useful for monitoring 3-D dynamics of intracellular particles.


Stochastic Reconstruction Of Multiple Source Atmospheric Contaminant Dispersion Events, Derek Wade, Inanc Senocak Mar 2013

Stochastic Reconstruction Of Multiple Source Atmospheric Contaminant Dispersion Events, Derek Wade, Inanc Senocak

Inanc Senocak

Reconstruction of intentional or accidental release of contaminants into the atmosphere using concentration measurements from a sensor network constitutes an inverse problem. An added complexity arises when the contaminant is released from multiple sources. Determining the correct number of sources is critical because an incorrect estimation could mislead and delay response efforts. We present a Bayesian inference method coupled with a composite ranking system to reconstruct multiple source contaminant release events. Our approach uses a multi-source data-driven Gaussian plume model as the forward model to predict the concentrations at sensor locations. Bayesian inference with Markov chain Monte Carlo (MCMC) sampling ...


Parallel Recording Of Neurotransmitters Release From Chromaffin Cells Using A 10 X 10 Cmos Ic Potentiostat Array With On-Chip Working Electrodes, Brian Kim, Adam Herbst, Sung Kim, Bradley Minch, Manfred Lindau Feb 2013

Parallel Recording Of Neurotransmitters Release From Chromaffin Cells Using A 10 X 10 Cmos Ic Potentiostat Array With On-Chip Working Electrodes, Brian Kim, Adam Herbst, Sung Kim, Bradley Minch, Manfred Lindau

Bradley Minch

Neurotransmitter release is modulated by many drugs and molecular manipulations. We present an active CMOS-based electrochemical biosensor array with high throughput capability (100 electrodes) for on-chip amperometric measurement of neurotransmitter release. The high-throughput of the biosensor array will accelerate the data collection needed to determine statistical significance of changes produced under varying conditions, from several weeks to a few hours. The biosensor is designed and fabricated using a combination of CMOS integrated circuit (IC) technology and a photolithography process to incorporate platinum working electrodes on-chip. We demonstrate the operation of an electrode array with integrated high-gain potentiostats and output time-division ...