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Search Publications by: William E. Wallace (Fed)

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Displaying 26 - 50 of 110

IMPACT OF IMMOBILIZATION SUPPORTS FOR POLYESTERS SYNTHESIS ACTIVITY OF CANDIDA ANTARTICA LIPASE B

January 1, 2010
Author(s)
Atul Bhangale, Santanu S. Kundu, Wenchun Xie, William E. Wallace, Kathleen M. Flynn, Kathryn L. Beers, Richard Gross
Epoxy functionalized supports are known to be suitable for industrial-scale immobilization of enzymes for biocatalysis. However, chemistry across these epoxy groups is known to affect the catalytic performance of the enzymes.In order to achieve a balance

PEG-HYDROGELS: SYNTHESIS, CHARACTERIZATION, AND CELL ENCAPSULATION

September 15, 2009
Author(s)
Sheng Lin-Gibson, Kaushik Chatterjee, James A. Cooper, William E. Wallace, Matthew Becker, Carl G. Simon Jr., Ferenc Horkay
A simple reaction to prepare controlled molecular mass (MM) poly(ethylene glycol) dimethacrylates (PEGDMs) of high purity and low polydispersity is outlined. PEGDMs were photo-polymerized to form hydrogels with and without bioactive moieties. The structure

Quantitative Measurement of the Polydispersity in the Extent of Functionalization of Glass Forming Resorcinarenes

May 1, 2009
Author(s)
William E. Wallace, Kathleen M. Flynn, Charles M. Guttman, David L. VanderHart, Vivek M. Prabhu, Anuja De Silva, Nelson Felix, Christopher K. Ober
The polydispersity in the degree of functionalization for two calix[4]resorcinarenes was determined by measuring their molecular mass distribution with matrix-assisted laser desorption/ionization time of flight mass spectrometry. A mathematical method for

Numerical Optimization of Matrix-Assisted Laser Desorption/Ionization Time-of- Flight Mass Spectrometry: Application to Synthetic Polymer Molecular Mass Distribution Measurement

May 26, 2007
Author(s)
William E. Wallace, Charles M. Guttman, Kathleen M. Flynn, Anthony J. Kearsley
A novel approach is described for the selection of optimal instrument parameters that yield a mass spectrum which best replicates the molecular mass distribution of a synthetic polymer. The application of implicit filtering algorithms is shown to be a

Development of NIST SRM 2881, an Absolute Molecular Mass Distribution Polymer Standard

September 1, 2006
Author(s)
William E. Wallace, Charles M. Guttman, Kathleen M. Flynn, Anthony J. Kearsley
We present a strategy to create an absolute molecular mass distribution polymer Standard Reference Material. To create a standard our methods must be free of operator bias (intentional or unintentional). The steps include sample preparation, instrument

Matrix-Assisted Laser Desorption/Ionization Time-of-Flight Mass Spectrometry Interlaboratory Comparison of Mixtures of Polystyrene With Different End Groups: Statistical Analysis of Mass Fractions and Mass Moments

July 1, 2005
Author(s)
Charles M. Guttman, S Wetzel, Kathleen M. Flynn, B M. Fanconi, David L. VanderHart, William E. Wallace
A matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) interlaboratory comparison was conducted on mixtures of synthetic polymers having the same repeat unit and closely matching molecular mass distributions but with

Synopsis of the 2004 ASMS Fall Workshop on Polymer Mass Spectrometry

February 1, 2005
Author(s)
William E. Wallace
This year s fall workshop of the American Society for Mass Spectrometry was on the topic of synthetic polymer mass spectrometry and was chaired by Robert P. Lattimer (Noveon, Inc.) and Chrys Wesdemiotis (University of Akron, Department of Chemistry). The

A Numerical Method for Mass Spectral Data Analysis

January 31, 2005
Author(s)
Anthony J. Kearsley, William E. Wallace, Javier Bernal, Charles M. Guttman
The new generation of mass spectrometers produces an astonishing amount of high-quality data in a brief period of time leading to inevitable data analysis bottlenecks. Automated data analysis algorithms are required for rapid and repeatable processing of

An Operator-Independent Approach to Mass Spectral Peak Identification and Integration

May 1, 2004
Author(s)
William E. Wallace, Anthony J. Kearsley, Charles M. Guttman
A mathematical algorithm is presented that accurately locates and calculates the area beneath mass spectral peaks using only reproducible mathematical operations and a NO user-selected sensitivity parameters. This represents a major refinement of last year

International Interlaboratory Comparison of Mixtures of Polystyrenes With Different End Groups Obtained by Matrix Assisted Laser Desorption/Ionization Time-of-Flight Mass Spectrometry (MALDI-TOF-MS): Preliminary Results

January 1, 2004
Author(s)
Charles M. Guttman, S Wetzel, Kathleen M. Flynn, B M. Fanconi, William E. Wallace, David L. VanderHart
NIST has sponsored a MALDI-TOF-MS interlaboratory comparison of mixtures of polymers of the same repeat unit with closely matching molecular masses but with different end groups. This interlaboratory comparison was designed to see how well a group of labs