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Search Publications by: Jeeseong C. Hwang (Fed)

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Displaying 51 - 75 of 84

Low-Cost, High-Throughput, Automated Counting of Bacterial Colonies

January 5, 2010
Author(s)
Matthew L. Clarke, Robert L. Burton, A. N. Hill, Maritoni A. Litorja, Moon H. Nahm, Jeeseong Hwang
Research involving bacterial pathogens often requires enumeration of bacteria colonies. Here we present a low-cost, high-throughput colony counting system consisting of colony counting software and a consumer-grade digital camera or document scanner. We

Probing Dynamic Fluorescence Properties of Single and Clustered Quantum Dots Towards Quantitative Biomedical Imaging of Cells

October 28, 2009
Author(s)
Hyeong G. Kang, Fuyuki Tokumasu, Matthew L. Clarke, Zhenping Zhou, Jianyong Tang, Tinh Nguyen, Jeeseong Hwang
We present results on dynamical fluorescence properties of bioconjugated nanocrystals or quantum dots (QDs) in different chemical and physical environments. A variety of QD samples were prepared and compared: isolated individual QDs, QDs aggregated into

Multimodal, Nanoscale, Hyperspectral Imaging Demonstrated on Heterostructures of Quantum Dots and DNA-Wrapped Single-Wall Carbon Nanotubes

October 21, 2009
Author(s)
Hyeong G. Kang, Matthew L. Clarke, Jianyong Tang, John T. Woodward IV, Shin G. Chou, Zhenping Zhou, Angela R. Hight Walker, Tinh Nguyen, Jeeseong Hwang
A multimodality imaging technique integrating atomic force, polarized Raman, and fluorescence lifetime microscopy and a 2D autocorrelation image analysis is applied to study the properties of a mesoscopic heterostucture of nanoscale materials. This

NIST s Integrated Colony Enumerator (NICE)

August 11, 2009
Author(s)
Matthew L. Clarke, Jeeseong Hwang
Enumeration of bacterial colonies in an agar plate is simple in concept, but automated colony counting is difficult due to variations in colony color, size, shape, contrast, and density, as well as colony overlap. Furthermore, in applications where high

Quantitative Characterization of Quantum Dot-labeled Lambda Phage for Escherichia coli Detection

July 24, 2009
Author(s)
Peter Yim, Matthew L. Clarke, Michael McKinstry, Silvia H. De Paoli Lacerda, Leonard F. Pease III, Marina A. Dobrovolskaia, Hyeong G. Kang, David T. Read, Shanmuga Sozhamannan, Jeeseong C. Hwang
We rapidly and quantitatively detect biological pathogens by combining the specificity of bacteriophage lambda with the sensitivity of CdSe/ZnS quantum dot (QD)-based fluorescence. Specifically, QD-decorated lambda phages bind to and allow detection of

Probing the dynamic fluorescence properties of single water-soluble quantum dots

April 1, 2008
Author(s)
J R. Krogmeier, Hyeong G. Kang, Matthew L. Clarke, p Yim, Jeeseong Hwang
The influence of surface modifications, including carboxyl-, amine-, and mercaptoundecanoicacid-functionalized chemistries, on the dynamic fluorescence properties of single quantum dots (QDs) are probed using a combined confocal fluorescence microscopy and

Biophotonic tools in cell and tissue diagnostics

May 1, 2007
Author(s)
Michael Brownstein, Robert A. Hoffman, Richard Levenson, Thomas E. Milner, Marla L. Dowell, Paul A. Williams, Grady S. White, Adolfas Gaigalas, Jeeseong C. Hwang
In order to maintain the rapid advance of biophotonics in the U.S. and to enhance our competitiveness worldwide, key measurement tools must be in place. As a part of a wide-reaching effort to improve the U.S. technology base, the National Institute of

Nanocrystal-Based Biomimetic System for Quantitative Flow Cytometry

February 6, 2007
Author(s)
Marina Dobrovolskaia, Hyeong G. Kang, Matthew L. Clarke, Anil Patri, Jeeseong Hwang
Flow cytometry has been instrumental in rapid analysis of single cells since the 1970s. One of the common approaches is the immunofluorescence study involving labeling of cells with antibodies conjugated to organic fluorophores. More recently, as the

Fluorescence Intermittency and Spectral Shifts of Single Bio-Conjugated Nanocrystals Studied by Single Molecule Confocal Fluorescence Microscopy and Spectroscopy

January 21, 2007
Author(s)
Hyeong G. Kang, Mathew Maye, Dmytro Nykypanchuk, Matthew L. Clarke, Peter Yim, J R. Krogmeier, Kimberly A. Briggman, Oleg Gang, Jeeseong Hwang
We have fabricated a combined measurement system capable of confocal microscopy and fluorescence spectroscopy to simultaneously evaluate multiple optical characteristics of single fluorescent nanocrystals. The single particle detection sensitivity is

Band 3 Modifications in Plasmodium Falciparum-Infected AA and CC Erythrocytes Assayed by Autocorrelation Analysis Using Quantum Dots

March 1, 2005
Author(s)
F Tokumasu, R M. Fairhurst, G R. Ostera, N J. Brittain, Jeeseong C. Hwang, T E. Wellems, J A. Dvorak
The molecular stability of hemoglobin is critical for normal erythrocyte functions, including oxygen transport. Hemoglobin C (HbC) is a mutant hemoglobin that has increased oxidative susceptibility due to an amino acid substitution ( 6: Glu to Lys). The

Effects of Surface Functionality and Humidity on The Adhesion Force and Chemical Contrast Measured With AFM

January 1, 2005
Author(s)
Tinh Nguyen, Xiaohong Gu, lijiang chen, Michael J. Fasolka, Kimberly Briggman, Jeeseong C. Hwang, Jonathan W. Martin
The ability to probe chemical heterogeneity with nanometer scale resolution is essential for developing a molecular level understanding of a variety of phenomena occurring at surfaces of materials. One area that could benefit greatly from nanoscale

Near-Field Polarimetric Characterization of Polymer Crystallites

August 1, 2004
Author(s)
Lori S. Goldner, S N. Goldie, Michael J. Fasolka, F Renaldo, Jeeseong Hwang, Jack F. Douglas
We use near-field polarimetry (NFP) to investigate thin film crystallites of isotactic polystyrene (iPS). NFP micrographs enabled quantitative optical characterization of the birefringence in these specimens with sub-diffraction limited resolution

Fourier Analysis Near-Field Polarimetry for Measurement of Local Optical Properties of Thin Films

July 1, 2003
Author(s)
Lori S. Goldner, Michael J. Fasolka, S Nougier, H P. Nguyen, Garnett W. Bryant, Jeeseong Hwang, K D. Weston, Kathryn L. Beers, A Urbas, Edwin L. Thomas
We present measurements of the local dichroism and birefringence of thin film specimens us ing techniques that combine near-field scanning optical microscopy (NSOM) and a novel polarization modulation (PM) polarimetry utilizing Fourier analysis of the

Near-Field Polarimetric Characterization of Semi-Crystalline Polymer Systems

March 1, 2003
Author(s)
S N. Goldie, Michael J. Fasolka, Lori S. Goldner, Jeeseong C. Hwang, Kathryn Beers
We have studied crystallization in thin films of isotactic polystyrene (iPS) to better understand the morphology and formation of these structures through the use of polarization modulation near-field scanning optical microscopy (PM-NSOM). Polymer