Universiẗat, Diss., 2000--Mainz. / Auch als gedr. Diss.

Presented as Plain's Thesis (Ph. D.)--University of Wisconsin--Madison, 1940. / Reprinted from Physical review, vol. 57, no. 3 (1 Feb. 1940). Includes bibliographical references.

Thesis (Ph. D.)--University of Wisconsin--Madison, 1950. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

Thesis (Ph. D.)--University of Texas at Austin, 2005. / Vita. Includes bibliographical references.

Universiẗat, Diss., 2001--Mainz.

Universiẗat, Diss., 2004--Mainz.

Degree Not Listed / Department of Diagnostic Medicine/Pathobiology / Roman Reddy R. Ganta / Anaplasmataceae family rickettsial bacteria are mostly vector-transmitted pathogens causing important diseases in several vertebrates, including humans, canines, and ruminants. Ehrlichia chaffeensis, a tick-transmitted intraphagosomal rickettsial bacterium, is the causative agent of human monocytic ehrlichiosis (HME). Little is known about how this and other related rickettsial organisms are able to reside and replicate within an acidified phagosome environment. Similarly, it is unclear how the infectious form of the bacterium maintains pH homeostasis in the extracellular milieu where the pH is about 7.35-7.45, before its infection to a naïve host cell. Sodium/cation: proton antiporters are integral membrane proteins reported from a wide range of species. They exchange sodium or other monovalent cations against protons across a plasma membrane in maintaining the cytoplasmic pH of a cell. We recently described a mutation within the Ech_0379 gene of E. chaffeensis that is predicted to encode for a Na+/H+ antiporter protein. The mutation caused the attenuated growth of the organism in vertebrate hosts, resulting in a reduced level of the bacterial presence in the circulation. In this study, we evaluated several antiporter protein genes of E. chaffeensis. Its genome contains 10 coding sequences encoding for polypeptides which may form at least six functional proteins. To define their function, a sodium sensitive Escherichia coli strain having a mutation in two of its three antiporter protein genes (EP432) is used to carry out the functional complementation assay with E. chaffeensis genes from their respective promoters. The EP432 strain has a growth defect during its replication in the presence of NaCl that can be restored with functional complementation. All six E. chaffeensis genes could complement the growth defect of EP432 under acidic pH, while Ech_0379 and Ech_0179 also complemented at basic pH. Ech_0179 complemented at neutral pH as well. The complementation of all genes at neutral and basic pHs, except Ech_0179 and Ech_0379, made EP432 E. coli strain be more sensitive to the presence of 200 mM NaCl. The channeling activity is verified independently by constructing a proteoliposome in vitro with the recombinant protein Ech_0379. The recombinant protein showed antiporter activity at all three pHs in the presence of 100 or 200 mM NaCl when assessed using the recombinant proteoliposome. This research is the first description of antiporter proteins of E. chaffeensis.

No description available.

Class of 2013 Abstract / Specific Aims: To determine whether concurrent use of a proton pump inhibitor (PPI) and a bisphosphonate represent an additional fracture risk compared with bisphosphonate use alone and to identify an increased risk of any particular fracture type. Methods: This study was a systematic review and meta-analysis of data collected from PubMed, Cochrane, OVID Medline, Google Scholar, and IPA. The authors utilized the search terms: bisphosphonate, fractures and proton pump inhibitors. Studies which met criteria of being English-language with adults 18 years of age and older were included. Main Results: The studies were cohort studies and primarily evaluated older adults. The summary effect was that use of a PPI with a bisphosphonate showed a slight increase in fracture risk when compared to bisphosphonate-only therapy (odds ratio [OR] 1.12, 95% confidence interval [CI], 1.06-1.18). Systematic review of similar studies showed varied results, making difficult any conclusion regarding fracture risk among the treatments. Conclusion: In this analysis, PPI + bisphosphonate demonstrated a slight increase in fracture rate without inference to an increase in any particular fracture type compared with bisphosphonate only. However, there is minimal data on the association or causal effect of this increase. The few studies available offered contradictory results. Additionally, database studies are subject to the possibility of residual confounding. Further research using randomized control trial (RCT) design evaluating long term use of bisphosphonates with or without PPI and their impact on fractures is needed to determine if there is an additional degree of fracture risk from the concurrent use.

Two-dimensional (2D) materials, referring to materials being just one atom thick, prove to be attractive not only in fundamental research but also in applications. Graphene, a single layer of carbon atoms arranged in hexagonal rings, is just the first among other materials (including hexagonal boron nitride and molybdenum disulfide) that could be isolated into mono-atomic layers. The presented thesis investigates proton transport through atomically thin two-dimensional materials. While the electronic, optical and mechanical properties of graphene and other 2D materials have been intensely researched over the past decade, much less is known on the interaction of these crystals with protons. It has been reported that most of the defect free two dimensional materials are impermeable to nearly all gases, molecules and ions. Whether proton, the smallest positively charged ion, could transport through two dimensional materials at a low energy level remains unknown. This work investigates proton transport through 2D materials, including graphene, hexagonal boron nitride and molybdenum disulfide, in two different systems: Nafion/Pd solid system and liquid/liquid interface system, both of which provided consistent results. Our results suggest that proton can transport through the interatomic spacings in the lattice of single layer BN and graphene, while single layer MoS2 is impermeable to protons. Single layer BN is the most conductive to protons among the 2D materials investigated in this thesis. Lower proton conductance of graphene is due to its delocalized π electrons while proton impermeability of MoS2 is due to the three atomic layers structure. Moreover, proton transfer is greatly facilitated by the deposition of platinum nanoparticles on the proton conductive 2D membranes to such a degree that platinum decorated BN seems to present negligible resistance to the transfer of protons through its lattice.