Thesis (Ph. D.)--University of Missouri-Columbia, 2000. / Typescript. Vita. Includes bibliographical references (leaves 168-176). Also available on the Internet.

Thesis (Ph. D.)--Rutgers University, 2009. / "Graduate Program in Microbiology and Molecular Genetics." Includes bibliographical references (p. 112-131).

Thesis (Ph. D.)--University of Missouri-Columbia, 2000. / Typescript. Vita. Includes bibliographical references (leaves 168-176). Also available on the Internet.

Thesis (Ph.D)--Biomedical Engineering, Georgia Institute of Technology, 2010. / Committee Chair: Griffin, Paul; Committee Member: Butera, Robert; Committee Member: Halpern, Michael; Committee Member: Nichols, Richard; Committee Member: Vidakovic, Brani. Part of the SMARTech Electronic Thesis and Dissertation Collection.

Thesis (Ph.D)--Earth and Atmospheric Sciences, Georgia Institute of Technology, 2010. / Committee Chair: Taillefert, Martial; Committee Member: DiChristina, Thomas; Committee Member: Sobecky, Patricia; Committee Member: Van Cappellen, Philippe; Committee Member: Webb, Samuel. Part of the SMARTech Electronic Thesis and Dissertation Collection.

Nanoparticles possess unique physical, chemical, optical and electronic properties stemming from their nanoscale dimensions and are currently used in catalysis, microelectronics, drug delivery, as well as other applications. However, due to their large surface area-to-volume ratio, nanoparticles have a strong tendency to coalesce and sinter during processing or usage over short time scales and at low temperatures, which lead to significant changes in behavior and performance. In this work, in-situ transmission electron microscopy (TEM) heating has been used to investigate the effects of particle size, temperature and carbon capping layers on sintering in face-centered cubic (FCC) metallic nanoparticles. For the first time, we make direct and real-time measurements of nanoparticle size, neck growth, dihedral angle and grain boundary motion during sintering, which are then used to calculate fundamental material transport parameters such as surface diffusivity and grain boundary mobility. We observe that carbon surface coatings typically present on most commercial nanoparticles can significantly inhibit sintering in nanoparticles. Also, a new mechanism for coalescence in nanoparticles is shown where small clusters on the support can initiate neck growth by forming a bridge between the nanoparticles consisting of individual atoms or small clusters of atoms. In-situ TEM experiments provide critical and valuable real-time dynamic information for direct investigation of the link between the evolution of sintering and controlling mechanisms, which conventional experiments such as post-mortem TEM observations are not capable of conveying. / text

This dissertation will examine the phenotype of pain facilitatory neurons in the rostral ventromedial medulla (RVM) and its role in neuropathic pain states. Activation of the descending facilitation pathways might be the result of plasticity in the RVM that is driven, at least in part, by the presence and activity of cholecystokinin type-2 receptors (CCK2R) mRNA expressing neurons. The expression of either opioid mu receptors (MOR) or CCK2R mRNA in the RVM was confirmed by in situ hybridization (ISH). Pretreatment with CCK8(s)-saporin resulted in a significant loss of CCK2R mRNA positive cells in the RVM, concomitant with a blockade of CCK8(s) induced hyperalgesia. The same treatment also significantly reduced the number of neurons labeled for MOR mRNA, hinting that MOR and CCK2R mRNA signals may be co-localized in some RVM cells. Consistent with these data, pretreatment with dermorphin-saporin significantly reduced the number of MOR mRNA labeled cells in the RVM, blocked RVM CCK8(s) induced hyperalgesia and reduced the number of CCK2R mRNA positive cells in the RVM. The co-localization was further confirmed by a dual label ISH approach using 35S-labeled CCK2R and Digoxigenin-labeled MOR riboprobes. Data showed that over 80% of labeled RVM neurons co-expressed both MOR and CCK2R mRNA, ~15% expressed only CCK2R mRNA, and very few cells expressed only MOR mRNA. The above findings may suggest that elimination of CCK2R mRNA expressing neurons result in removal of the driving force for descending facilitation from RVM, hereby block the development of neuropathic pain. Rats pretreated with CCK8(s)-saporin conjugates had a full reversal of thermal sensory threshold and partial reversal of tactile threshold starting at day 5 after SNL. The lesion effects of RVM CCK-SAP were evaluated by ISH. Comparing to saporin pretreated groups, CCK8(s)-saporin pretreatment significantly reduced the numbers of CCK2R mRNA labeled neurons within RVM. The data suggest that selective ablation of CCK2R mRNA expressing cells in RVM is sufficient to block the development of neuropathic pain, and thus confirm the hypothesis that CCK2R mRNA expressing cells may be an important player in descending facilitation from RVM as a mechanism of neuropathic pain.

Nicotinic acetylcholine receptors (nAChR) are neurotransmitter-gated ion channels that exist as a family of subtypes defined by unique subunit compositions. nAChR containing α6 subunits (α6*-nAChR) have attracted interest because α6 subunits are thought to be localized in brain regions implicated in reward, mood and drug dependence. To provide new information necessary toward a more complete understanding of roles of α6*-nAChR in neuropsychiatric health and disease, three lines of investigation were pursued. A set of stably transfected, human, immortalized cell lines were generated that heterologously express nAChR α6 subunits in combination with other nAChR subunits found in reward brain regions (nAChR subunit combinations α6β2, α6β4, α6β2β3, α6β4β3, α6β2β3α5, α6β4β3α5, α6α4β2β3 and α6α4β4β3). The α6α4β2β3 combination may have a functional response to epibatidine that differs from that of the α4β2 nAChR. A unique binding site was identified in cells transfected with the α6β4β3α5 nAChR subunit combination. Messenger RNA fluorescence in situ hybridization (mRNA FISH) studies established regional and celluar distribution of nAChR α6 subunit mRNA in the mouse brain. The third line of study extended this work to examine potential co-expression of nAChR α6 subunits and glutamic acid decarboxylase (GAD) or tyrosine hydroxylase (TH) as labels of GABAergic and dopaminergic/catecholaminergic neurons respectively, using tandem mRNA FISH and fluorescence immunohistochemistry. nAChR α6 subunit signal in the substantia nigra (SN) and ventral tegmental area (VTA) was congruent with previous studies. Message was also detected in the amydala, dentate gyrus, striatum, zona incerta, and cingulate, entorhinal, perirhinal, piriform, and prelimbic cortices. nAChR α6 mRNA was coexpressed with GAD in the amygdala, dentate gyrus, striatum, SN, VTA and cingulate, entorhinal, prelimbic and prelimbic cortices. TH was exclusively co-localized with nAChR α6 mRNA in the SN and VTA. Findings suggest extended roles for α6*-nAChR in the brain, particularly in the control of GABAergic neuronal activity and/or GABA release. These studies provide new insights into the composition of α6*-nAChR, the localization and cellular origins of nAChR α6 subunit expression. Data collected suggest roles for α6*-nAChR in many brain regions, including those involved in higher order processes involved in drug dependence and reward, and in modulation of inhibitory neurotransmission.

No description available.

A novel method to detect and quantify the growth of the solid electrolyte interphase (SEI) on battery electrode materials using in-situ spectroscopic ellipsometry (SE) is presented. The effects of additives in 1 M LiPF6/EC:DEC (1:2) electrolyte on the SEI were studied. Thin film electrodes of a-Si, Ni, and TiN were prepared by magnetron sputtering for use with a custom-designed tubular in-situ electrochemical cell. Li/a-Si and Li/Ni in-situ cells in 0.1 M LiPF6/EC:DEC (1:2) were studied by galvanostatic chronopotentiometry. Large changes in the ellipsometric parameters, ? and ?, were observed for both materials. These changes were closely related to the state of charge of the in-situ cell. The formation of an a-LixSi alloy, the formation of an SEI layer, or both contributed to these large changes for a Li/a-Si in-situ cell. For a Li/Ni in-situ cell, a thin transparent surface layer was observed. The surface layer, presumably made from SEI species and species from the displacement reaction between NiO and Li, increased to roughly 17 nm during the first discharge. During the first charge, the surface layer thickness decreased to roughly 5.5 nm and could not be removed, even at high potentials. The effect of vinylene carbonate (VC) and fluoroethylene carbonate (FEC) additives on SEI formation were studied using a Li/TiN in-situ cell in 1 M LiPF6/EC:DEC (1:2) by potentiostatic chronoamperometry. SEI thicknesses for cells containing no additives, VC, and FEC were roughly 18 nm, 25 nm and 30 nm, respectively, after a 10 h hold at 0.1 V. SE is a useful technique for measuring thin film growth in-situ on electrode materials for Li-ion batteries.