Sol-gel capillary microextraction (CME) is a new direction in solvent-free extraction and preconcentration of trace analytes. CME presents significant interest in environmental, pharmaceutical, petrochemical, biomedical, agricultural, food, flavor, and a host of other important areas. Sol-gel CME utilizes advanced material properties of organic-inorganic hybrid sol-gel polymers to perform efficient extraction and enrichment of target analytes from a variety of matrices. In this dissertation, two novel sol-gel coatings were developed for CME: (a) sol-gel benzyl-terminated dendrimer coating, and (b) sol-gel polytetrahydrofuran (poly-THF) coating. A detailed investigation was conducted to evaluate the performance of the newly developed sol-gel coatings in solvent-free extraction of a wide range of polar and nonpolar analytes. Sol-gel chemistry was used to chemically immobilize dendrimer- and poly-THF-based hybrid organic-inorganic coatings on fused silica capillary inner surface. The sol-gel coatings were created using a coating solution containing a sol-gel active organic component (dendrimer or poly-THF), a sol-gel precursor (methyltrimethoxysilane, MTMOS), a sol-gel catalyst (trifluoroacetic acid, TFA, 5% water) and a deactivating reagent (hexamethyldisilazane, HMDS). Sol-gel reactions were conducted inside a hydrothermally treated fused silica capillary for 60 min. A wall-bonded sol-gel coating was formed via condensation of silanol groups residing on the capillary inner surface with those on the sol-gel network fragments evolving in close vicinity of the capillary walls. Due to the strong chemical bonding with capillary inner walls, these sol-gel coatings showed excellent thermal and solvent stability in CME in hyphenation with gas chromatography (GC).

Two highly polar sol-gel coatings were developed for capillary microextraction (CME). One of the coatings contained cyanopropyl-polydimethylsiloxane (CN-PDMS) and the other low molecular weight polyethylene glycol. These highly polar coatings were immobilized via sol-gel chemistry allowing for direct chemical bonding to the inner surface of fused silica capillaries. These sol-gel coated microextraction capillaries were employed in CME for solvent-free microextraction and preconcentration of trace analytes (polar, moderately polar, and nonpolar) from aqueous matrices. CN-PDMS and short chain PEG extraction phases exhibit both polar and polarizable characteristics. Therefore, both sol-gel CN-PDMS and short chain sol-gel PEG coatings were able to extract analytes of different polarity from aqueous media. Both sol-gel CN-PDMS and sol-gel PEG coatings provided effective extraction of polar analytes such as free fatty acids, alcohols, and phenols without requiring derivatization, pH adjustment or salting out procedures commonly used in SPME experiments with conventional coatings. For each of these coatings, detection limits on the order of nanogram/liter (ng/L) were achieved for both polar and nonpolar analytes extracted simultaneously from aqueous media followed by GC-FID analysis. Both sol-gel CN-PDMS and short chain sol-gel PEG coated microextraction capillaries showed excellent run-to-run and capillary-to-capillary extraction reproducibility (GC peak area RSD < 6% & 5%, respectively) for nonpolar as well as polar analytes. For the sol-gel CN-PDMS coatings, the upper allowable conditioning temperatures were 330 degrees C and 350 degrees C, for the extraction of polar and nonpolar organic analytes, respectively. Similarly, the sol-gel PEG coatings used for the extraction of polar organic analytes survived a conditioning temperature of 340 degrees C. Both sol-gel CN-PDMS and sol-gel PEG coated microextraction capillaries showed no significant changes in the peak areas of the extracted analytes even after being washed with organic solvents (dichloromethane and methanol (1:1), v/v) for 24 hours. The excellent thermal and solvent stabilities can be attributed to the presence of chemical bonds between the sol-gel coatings and the fused silica surface.

Passive removal materials (PRMs) are building materials or furnishings that can effectively control indoor pollution without substantial formation of chemical byproducts and without energy penalty. To assess clay wall plaster as an effective PRM for improving air quality by controlling ozone, perceived air quality (PAQ) was determined in the presence of eight combinations of an emitting and reactive pollutant source (new carpet), clay plaster applied to gypsum wallboard, and chamber air with and without ozone. A panel of 18 to 23 human subjects assessed air quality in twin 30 m3 chambers using a continuous acceptability scale. Air samples were collected immediately prior to panel assessment to quantify concentrations of C5 to C10 saturated n-aldehydes and two aromatic aldehydes that are commonly produced by reaction of ozone with carpet. Perceived Air Quality was most acceptable and concentrations of aldehydes were lowest when only clay plaster or both clay plaster and carpet were present in the chambers without ozone. The least acceptable PAQ and the highest concentrations of aldehydes were observed when carpet and ozone were present together; addition of clay plaster for this condition improved PAQ and considerably decreased aldehyde concentrations. Ozone deposition and byproduct emissions of the clay wall plaster were also assessed using 48 liter stainless steel chambers. Clay plaster applied to gypsum wallboard that had been exposed in a test house (UTest House) for one year effectively removed 88% of the ozone, and emitted high aldehyde concentrations when exposed to high purity air that did not increase when the material was exposed to ozone. The outcome of these experiments leads to speculation that the clay plaster adsorbed contaminants in the test house and then re-emitted them upon exposure to clean air in the small chambers. / text

Lipid oxidation has important consequences in the edible oil industry, producing compounds with sensory impact and thus reducing the economic value of the products. This work focused on the development of two Fourier transform infrared (FTIR) spectroscopy methods for the measurement of peroxide value (PV) and anisidine value (AV), representing the primary and secondary oxidation products of edible oils. / The infrared method developed for PV determination was based on a mathematical treatment by the partial least squares method of the information contained in the spectral region between 3750 and 3150 cm$ sp{-1}$. / The second method developed considered aldehyde content and anisidine value, a measure of secondary oxidation products. / The two methods developed are rapid ($ sim$2 min/sample) and have the advantage of being automatable. An infrared system coupled to a computer can collect the spectrum of an oil, analyze it and present a report without the need for personnel trained in FTIR spectroscopy. The cost of such a system would rapidly be absorbed through savings on personnel cost, time and chemical reagents required for conventional chemical methods and as such provides a useful advance in quality control methodology for the edible oils sector. (Abstract shortened by UMI.)

Parkinson’s disease, dementia with Lewy bodies and multiple system atrophy are disorders featuring accumulation of Lewy bodies in brain. The main component of these large insoluble intracellular inclusions is the presynaptic protein alpha-synuclein (α-synuclein). It is generally believed that α-synuclein monomers adopt an abnormal conformation that favors the formation of soluble oligomers or protofibrils and, eventually, insoluble fibrils depositing as Lewy bodies. Notably, the intermediately sized oligomers/protofibrils seem to have particular neurotoxic effects. Several factors may influence the formation of α-synuclein oligomers/protofibrils, e.g. the reactive aldehydes 4-hydroxy-2-nonenal (HNE) and 4-oxo-2-nonenal (ONE) formed during oxidative stress. The overall aims of this thesis were to investigate biophysical and biochemical properties of in vitro generated α-synuclein oligomers, characterize their functional effects on cell and animal disease models as well as to explore whether their formation could be prevented in a cell culture model for oligomerization.  Here, it was found that α-synuclein rapidly formed oligomers after incubation with both ONE and HNE. The resulting oligomers were stable and did not continue to form insoluble fibrils. By comparing HNE- and ONE induced α-synuclein oligomers biochemically they were both found to exhibit extensive β-beta sheet structure and had a molecular size of ~2000 kDa. However, they differed in morphology; the ONE induced α-synuclein oligomers described round amorphous species whereas the HNE induced α-synuclein oligomers appeared as elongated protofibril-like structures. Both these oligomers were cell internalized to varying degrees and induced toxicity in neuroblastoma cells. In addition, the ONE induced α-synuclein oligomers seemed to initiate aggregation of monomeric α-synuclein in vitro, but failed to do so in vivo. Finally, treatment of α-synuclein overexpressing cells with monoclonal antibodies specific for α-synuclein significantly reduced aggregation and lowered levels of the protein, suggesting increased turnover in these cells.  To conclude, this thesis has characterized different oligomeric α-synuclein species, which may have properties similar to soluble species central to the pathogenesis of Parkinson’s disease and other disorders with α-synuclein pathology. For therapeutic strategies it is important to selectively target such harmful protein species and avoid interaction with other forms of α-synuclein, which may have vital physiological cellular functions.

Thesis (Ph. D.)--University of Hong Kong, 2008. / Also available in print.

Diss. (sammanfattning) Linköping : Univ., 2003. / Härtill 5 uppsatser.

Thesis (Ph.D. in Toxicology) -- University of Colorado Denver, 2008. / Typescript. Includes bibliographical references (leaves 111-122). Free to UCD affiliates. Online version available via ProQuest Digital Dissertations;

Thesis (M.S.)--Florida State University, 2005. / Advisor: Dr. Marie E. Krafft, Florida State University, College of Arts and Sciences, Dept. of Chemistry and Biochemistry. Title and description from dissertation home page (viewed Sept. 19, 2005). Document formatted into pages; contains 147 pages. Includes bibliographical references.

Thesis (Ph.D. in Toxicology) -- University of Colorado, 2005. / Typescript. Includes bibliographical references (leaves 141-156). Free to UCDHSC affiliates. Online version available via ProQuest Digital Dissertations;