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by Linda Shiou-Mei Ooi. / Thesis (Ph.D.)--Chinese University of Hong Kong, 1998. / Includes bibliographical references (p. 118-126). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Mode of access: World Wide Web. / Abstracts in English and Chinese.

by Lam Ying Wai. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2001. / Includes bibliographical references (p. 193-209). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Mode of access: World Wide Web. / Abstracts in English and Chinese.

Background. Social deprivation or isolation accelerates the progression of atherosclerosis in several animal models of the disease. Conversely, stable social environment has been associated with reduction in the extent and severity of atherosclerosis. While positive social interactions are thought to be related to this protective effect, little is known about the physiological mechanisms responsible. Recently, the neurohypophyseal peptide, oxytocin (OT), has been found to play a role in both positive social interactions and cardiovascular homeostasis, suggesting that this neuropeptide may be responsible for mediating the beneficial effects of positive social environment on atherosclerosis. The first aim of the current study is to examine the potential anti-inflammatory effects of OT on in vitro cellular models involved in the pathophysiology of atherosclerosis. The second aim is to examine whether long-term administration of OT slows the progression of atherosclerosis in apoE-/- mice. The third aim is to obtain evidence in vivo that OT is impacting disease through novel anti-inflammatory effects on tissues important in atherogenesis. Methods. 1) Human macrophage-like (DTHP-1) cells and human aortic endothelial cells (HAECs) were stimulated with lipopolysaccharde (LPS) alone, and in the presence of different concentrations of OT, and IL-6 secretion was measured. 2) ApoE-/- mice were socially isolated at 12 weeks of age and continuously infused with OT (n=24) or vehicle (n=21) from subcutaneously implanted osmotic minipumps for 12 weeks. Plasma levels of lipids, adiponectin, insulin, and CRP were assessed pre- and post-treatment. Extent of aortic atherosclerosis (percent lesion area) was assessed post-treatment and areas of high lesion prevalence were compared between OT and vehicle (VH) control groups. Constitutive release of IL-6 from ex vivo adipose tissue samples taken from a subset (n=12/group) was compared between treatment groups. Results. 1) OT demonstrated dose-dependent inhibition of LPS-induced IL-6 secretion from macrophages (35-55%, p < 0.01) and aortic endothelial cells (15-25%, p < 0.01). 2) ApoE-/- mice continuously infused with OT displayed decreased plasma CRP levels after 6 weeks of treatment and diminished lesion area at the thoracic aorta after 12 weeks of treatment relative to vehicle control animals (37%, p < 0.05). Additionally, adipose tissue samples taken from OT infused mice showed decreased constitutive release of IL-6 (30%, p < 0.01). These findings were unrelated to changes in plasma lipids, insulin, physical activity levels, or 24-hour corticosterone secretion. Discussion and Conclusions. These findings demonstrate that OT is capable of inhibiting stimulated pro-inflammatory cytokine production in macrophages and aortic endothelial cells in vitro, and constitutive release from adipose tissue in vivo. OT also decreased circulating CRP levels and slowed the progression of early stage atherosclerosis in an aortic region of high lesion prevalence in socially isolated apoE-/- mice. Taken together, these results suggest that increased peripheral OT could be partially responsible for the beneficial effect of positive social environment on atherosclerosis.

Thesis (Ph. D.)--Texas A&M University, 2005. / Vita. Includes bibliographical references (p. 150-156). Also available online via the Texas A&M Digital Repository website (https://txspace.tamu.edu/).

Triclosan is incorporated in a wide array of medical and consumer products as an antimicrobial agent or preservative. Disposal of these products transport triclosan into wastewater and later into soils and surface waters. Due to incomplete removal of triclosan in wastewater treatment plants, contamination of triclosan in the environment has raised several concerns, including: (i) an aid to the development of cross-resistance to antibiotics, (ii) the toxicity to ecological health, (iii) the formation of chlorodioxins from triclosan and its metabolites. By using 14C-labeled triclosan, 14CO2 was observed in activated sludge samples, suggesting that triclosan was biodegraded. However, little is known about the microorganisms responsible for triclosan biodegradation in activated sludge. The goal of this study is to better understand biodegradation of triclosan in activated sludge. Two specific objectives are: (i) isolating and characterizing triclosan-degrading bacteria from activated sludge, (ii) characterizing the cometabolic degradation of triclosan through an ammonia-oxidizing bacterium Nitrosomonas europaea. A triclosan-degrading strain, KCY1, was successfully isolated from the activated sludge. The strain KCY1 completely degraded triclosan in three days when OD600 was 0.4. Based on 16S rRNA analysis, the strain KCY1 has 97% similarity with Phingomonas or Phingopyxis. Negative results of oxygenase activity assays suggested that other enzymes rather than oxygenases might be responsible for the triclosan biodegradation. Experiments using N. europaea showed that triclosan could be cometabolized. In the presence of inhibitor for ammonia monooxygenase (AMO), N. europaea was unable to degrade triclosan, suggesting that AMO might be responsible for triclosan degradation. Triclosan appeared to competitively inhibit ammonia oxidation by N. europaea. Results of this study showed that triclosan might be effectively biodegraded by triclosan-degrading cultures, strain KCY1 and N. europaea.

Social isolation has been linked with negative health effects in senior women. The purpose of this study was to understand the lived experiences of socially-isolated senior women. Local senior-serving organizations assisted with the recruitment of six socially-isolated senior women to participate in individual qualitative interviews. Three service providers were also interviewed. Seniors’ interviews were analyzed using interpretive phenomenological analysis and service provider interviews were analyzed using thematic analysis. Three superordinate themes were derived from the senior interviews: social needs, self-perceptions of isolation and loneliness, and constraints to and facilitators of social engagement. Five superordinate themes were derived from the service provider interviews: definitions of social isolation, differences between social isolation and loneliness, gender differences in isolation and loneliness, identifying socially-isolated seniors, and essential components of initiatives aimed at reducing social isolation. The views of socially-isolated seniors are important to understand to develop programs and policies that promote healthy aging.

The unprecedented growth of computing power and communication bandwidth in the last few decades has driven an explosion in the size and complexity of application software. Specifically, it has spurred an almost universal adoption of modular and extensible software designs, from ordinary PC applications, to operating systems kernels, and even to embedded systems. In many cases, however, the ability to extend software systems has come hand in hand with the need to isolate them from untrusted or potentially faulty extensions. This dissertation will focus on the important problem of code isolation, where existing techniques vary in many and often interrelated dimensions such as granularity, code complexity, invocation latency, dynamism, isolation strategy, permissible extension functionality, and degree of integration with the operating system kernel. Specifically, the implementation of a particular technique imposes restrictions on the properties of extensions. Examples include proof-based techniques that are only applicable to simple extensions of small granularity, hardware-based isolation techniques that typically incur a measurable invocation latency due to hardware re-configuration overhead, and programming language techniques that impose implementation and compiler restrictions. The goal of this dissertation is to explore the design space of code isolation techniques, identify characteristics of individual approaches, and then argue for and design a hybrid approach that combines their advantages while avoiding their drawbacks. The contributions of this thesis will be threefold: (1) a taxonomy of metrics and properties relevant to software code isolation techniques, (2) the design and implementation of a novel hybrid architecture for safe kernel extension with pliable characteristics, and (3) an evaluation of the hybrid approach and comparison with homogeneous alternatives.

Triclosan is incorporated in a wide array of medical and consumer products as an antimicrobial agent or preservative. Disposal of these products transport triclosan into wastewater and later into soils and surface waters. Due to incomplete removal of triclosan in wastewater treatment plants, contamination of triclosan in the environment has raised several concerns, including: (i) an aid to the development of cross-resistance to antibiotics, (ii) the toxicity to ecological health, (iii) the formation of chlorodioxins from triclosan and its metabolites. By using 14C-labeled triclosan, 14CO2 was observed in activated sludge samples, suggesting that triclosan was biodegraded. However, little is known about the microorganisms responsible for triclosan biodegradation in activated sludge. The goal of this study is to better understand biodegradation of triclosan in activated sludge. Two specific objectives are: (i) isolating and characterizing triclosan-degrading bacteria from activated sludge, (ii) characterizing the cometabolic degradation of triclosan through an ammonia-oxidizing bacterium Nitrosomonas europaea. A triclosan-degrading strain, KCY1, was successfully isolated from the activated sludge. The strain KCY1 completely degraded triclosan in three days when OD600 was 0.4. Based on 16S rRNA analysis, the strain KCY1 has 97% similarity with Phingomonas or Phingopyxis. Negative results of oxygenase activity assays suggested that other enzymes rather than oxygenases might be responsible for the triclosan biodegradation. Experiments using N. europaea showed that triclosan could be cometabolized. In the presence of inhibitor for ammonia monooxygenase (AMO), N. europaea was unable to degrade triclosan, suggesting that AMO might be responsible for triclosan degradation. Triclosan appeared to competitively inhibit ammonia oxidation by N. europaea. Results of this study showed that triclosan might be effectively biodegraded by triclosan-degrading cultures, strain KCY1 and N. europaea.