Multimodal methods for blind source separation of audio sources

The enhancement of the performance of frequency domain convolutive blind source separation (FDCBSS) techniques when applied to the problem of separating audio sources recorded in a room environment is the focus of this thesis. This challenging application is termed the cocktail party problem and the ultimate aim would be to build a machine which matches the ability of a human being to solve this task. Human beings exploit both their eyes and their ears in solving this task and hence they adopt a multimodal approach, i.e. they exploit both audio and video modalities. New multimodal methods for blind source separation of audio sources are therefore proposed in this work as a step towards realizing such a machine. The geometry of the room environment is initially exploited to improve the separation performance of a FDCBSS algorithm. The positions of the human speakers are monitored by video cameras and this information is incorporated within the FDCBSS algorithm in the form of constraints added to the underlying cross-power spectral density matrix-based cost function which measures separation performance. [Continues.

Bioanalytical methods for studies of homocysteine and novel cardiovascular disease indicators

This dissertation explores the development of analytical methods for studies of CVD biomarkers and related biomolecular indicators. Initially, spectroscopic studies were conducted to investigate the chemical reactivity of homocysteine (Hcy), an independent CVD risk factor and serological biomarker. Consequently, we proposed an alternate theory for in vivo Hcy clearance based on spontaneous pyridoxal tetrahydrothiazine (PT) formation from Hcy and pyridoxal. The validity of PT-assisted Hcy clearance was further evaluated by use of capillary electrophoretic methods, which allowed rapid monitoring of protein oligomerization in PT-protein reaction mixtures. The results of these studies suggest that PT formation is a plausible mechanism for Hcy clearance. Moreover, PT formation was shown to protect proteins from post-translational modification by homocysteine thiolactone. This dissertation also addresses the need for rapid and direct detection methods for CVD biomarkers. Accordingly, we introduced the first plasmon resonant GNP sensing scheme for protein homocystamide. The nanosensor provides visual conformation of protein homocystamide (N-Hcy-protein) by way of a red-to-blue color change. Further sensor investigations conducted with protein nanobioconjugates revealed that the GNP sensing mechanism is dependent on several complex physiochemical and biomolecular interactions including nanoparticle self-assembly, interparticle disulfide cross-linking, and modification-induced protein conformational changes. This dissertation also continues previous atherosclerotic tissue characterization studies by demonstrating the feasibility of using hybrid organic-immunoaffinity extraction for GC-MS analysis of polycyclic aromatic hydrocarbons in human heart plaque samples. This body of work is significant because it proposes new bioanalytical technologies that could enhance CVD screening and treatment

On-line coupling of capillary electrophoresis and liquid chromatography with electrospray ionization mass spectrometry for protein characterization

On-line coupling of capillary isoelectric focusing (CIEF) and liquid chromatography (LC) with electrospray ionization mass spectrometry (ESIMS) is utilized for protein characterization;A microdialysis junction, based on a microdialysis membrane connecting both a separation capillary and a short, sharply tapered microelectrospray emitter capillary, is demonstrated for CIEF-ESIMS. Besides the electrical connection across the microdialysis junction, post-run acidification via the dialysis membrane is demonstrated for enhancing the protonation and the ionization efficiency of focused proteins while maintaining separation efficiency, resolution, and sensitivity in CIEF-ESIMS;On-line combination of CIEF with ESI-FTICRMS is demonstrated for high resolution analysis of model proteins, human hemoglobin variants, and Escherichia coli proteins. The acquisition of high-resolution mass spectra of hemoglobin [beta] chains allows direct identification of hemoglobin variants A and C, differing in molecular mass by 1 dalton. Direct mass determination of cellular proteins separated in the CIEF capillary is achieved using their isotopic envelopes obtained from ESI-FTICRMS;An integrated approach, involving the combination of exoglycosidase enzyme array with LC/MS/MS, is demonstrated for structural analysis of carbohydrate moieties of glycopeptides from a glycoprotein digest. The molecular mass information from a series of controlled digestions together with specific compositions of exoglycosidases in the enzyme array provide the sequence and linkage of individual glycan species attached to glycopeptides and glycoproteins