Biomedical subjects

Scott W Huffman

Publications and source records attributed to Scott W Huffman.

4 recordsLinked to original sources

PubMed2005

Enhancement of infrared spectral images for maximizing chemical information by minimizing baseline interferences.

The popularity of spectral images in many areas of analysis has greatly increased during the last decade due to the development of charge-coupled device (CCD) and infrared sensitive cameras. Large amounts of spatial information can be obtained in short periods of time. The general goal in analytical chemistry is to convert spectral images into chemical images, which show the spatial locations of various chemical components. Self-modeling multivariate curve resolution methods can be used to extract pure component spectra from the mixture spectra in images and produce chemical images. However, there is a difficulty in processing infrared spectral images due to large pixel-to-pixel baseline variations. Herein, a method for minimizing baseline interferences using fast Fourier transform (FFT) filtering in both the spectral and spatial domains is discussed. The methodology is demonstrated on a microscopic sample of butter contaminated with non-pathogenic E. coli and on a cross-sectional sample of rabbit aorta containing plaque. The processing to reduce baseline effects improved the spatial resolution without compromising the spectral resolution.

Algorithms↗

PubMed2004

Reorganizational dynamics of multilamellar lipid bilayer assemblies using continuously scanning Fourier transform infrared spectroscopic imaging.

We employ an implementation of rapid-scan Fourier transform infrared (FT-IR) microspectroscopic imaging to acquire time-resolved images for assessing the non-repetitive reorganizational dynamics of aqueous dispersions of multilamellar lipid vesicles (MLVs) derived from distearoylphosphatidylcholine (DSPC). The spatially and temporally resolved images allow direct and simultaneous determinations of various physical and chemical properties of the MLVs, including the main thermal gel to liquid crystalline phase transition, comparisons of vesicle diffusion rates in both phases and the variation in lipid bilayer packing properties between the inner and outer lamellae defining the vesicle. Specifically, in the lipid liquid crystalline phase, the inner bilayers of the MLVs are more intermolecularly ordered than the outer regions, while the intramolecular acyl chain order/disorder parameters, reflecting the overall characteristics of the fluid phase, remain uniform across the vesicle diameter. In contrast, the lipid vesicle gel phase displays no intermolecular or intramolecular dependence as a function of distance from the MLV center.

Diffusion↗

PubMed2003

Analysis of microbial components using LC-IR.

Characterization of bacteria is currently an important research area in the medical, military, food, and agricultural sciences. In recent years, FT-IR has found an application as a microbiological detection method and as a general research tool. When coupled with a liquid chromatographic system, a new facet of research has evolved. By utilizing the separation ability of typical liquid chromatography systems, matrix elimination is possible, therefore allowing for clean spectra of cellular components. Information about the compositional makeup of various bacteria enhances the overall understanding of biology at the cellular level, provides a quantification of the chemistry of cellular processes, and can be used as a general identification tool. Both whole cells and lysed Escherichia coli cells were investigated in the present study. The cellular components consisting of proteins, glycoproteins, phospholipids, fatty amides and acids, and genomic materials were separated, isolated, and identified by FT-IR.

Bacterial Proteins↗

PubMed2003

Raman microspectroscopy: a comparison of point, line, and wide-field imaging methodologies.

Three different Raman microspectroscopic imaging methodologies using a single experimental configuration are compared; namely, point and line mapping, as representatives of serial imaging approaches, and direct or wide-field Raman imaging employing liquid-crystalline tunable filters are surveyed. Raman imaging data acquired with equivalent low-power 514.5-nm laser excitation and a cooled CCD camera are analyzed with respect to acquisition times, image quality, spatial resolution, intensity profiles along spatial coordinates, and spectral signal-to-noise ratios (SNRs). Point and line mapping techniques provide similar SNRs and reconstructed Raman images at spatial resolutions of approximately 1.1 microm. In contrast, higher spatial resolution is obtained by direct, global imaging (approximately 313 nm), allowing subtle morphological features on test samples to be resolved.

Journal Article↗