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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
231

The efficacy of a combined cognitive-behavioural and interpersonal therapy approach to the treatment of fibromyalgia syndrome : a randomized controlled trial

Langford, Melanie Marie 24 July 2008 (has links)
The purpose of the current study was to develop a manualized treatment for fibromyalgia syndrome (FM) and to examine the efficacy of the treatment in a randomized controlled clinical trial. FM is a chronic musculoskeletal pain disorder characterized by tender points and generalized pain. Depression, chronic fatigue, and sleep disturbance are common. A biopsychosocial model served as a framework for understanding FM by integrating psychological, social, and physical factors. Cognitive-behavioural therapy (CBT), an empirically validated treatment for arthritis, has also been used with FM patients in an attempt to improve pain control, reduce disability, and increase self-efficacy. Overall, the attention/placebo controlled studies employing CBT as a treatment for FM show that it is not superior to a credible attention placebo. The current study attempted to combine the necessary components of CBT with interpersonal therapy to address relational patterns and personality characteristics that can affect ability to cope with chronic pain. One hundred and five women diagnosed with FM by a rheumatologist were randomly assigned to the CBT-interpersonal treatment condition or an attention-control condition. There were 8 treatment groups with a mean of 6-7 participants in each. The treatment consisted of weekly 2-hour sessions over 8 consecutive weeks. Outcome measures included: FM impact, pain, health care utilization, depression, coping, and self-efficacy. An intention-to-treat analysis was conducted. Results showed that the impact of FM symptoms was reduced following treatment compared to the control group and this was statistically and clinically significant, but was not maintained at 3-month follow-up. Significant improvements were also observed in coping strategies, some of which were maintained at follow-up. Importantly, self-efficacy improved significantly following treatment compared to the control group. Self-efficacy beliefs have been related to pain, coping efforts, disability, and psychological functioning. Directions for future research may include a focus on long-term maintenance of treatment gains that may be mediated by improvements in self-efficacy. There is strong evidence that changes in self-efficacy are enduring and affect changes in health behaviours and health status.
232

A comparison of NMHC oxidation mechanisms using specified gas mixtures and trace-P field data

Gong, Xingyi 15 November 2005 (has links)
This work has focused on showing the differences among four different NMHC oxidation mechanisms: GT Lurmann, CBIV, RACM, and SAPRC mechanisms. This study was carried out to characterize these mechanisms using both specified NOx/NMHC gas mixtures and observational data from NASAs TRACE-P campaign. The differences among these mechanisms were found to be mainly driven by the use of different kinetic data and the specifics of each oxidation scheme. In the test runs, the differences between mechanisms were shown to be dependent on the levels of NOx and NMHC, as well as the reactivity of NMHC species used. Typically, propane had the smallest impact on all product species, whereas propene had the largest. Differences in the predicted levels of OH and HO2 were much smaller compared to those for CH3O2 and CH2O due to the fact that HOx species were generally less sensitive to the presence of NMHCs. During TRACE-P, which involved flights over only marine areas that were slightly polluted by the inflow of pollutants, the alkanes were the dominant NMHC family. Thus, most of the model runs involved relatively low levels of NMHCs and NOx. Therefore, the levels of OH, HO2, CH3O2, and CH2O predicted by the four mechanisms were not dramatically different. A net O3 increase was found only in areas where the NMHC reactivity was high. Because of the similar O3 destruction rates given by all four mechanisms, the difference in O3 tendency among these mechanisms was mainly determined by the O3 formation rate. A significantly higher (e.g., ~30%) O3 formation was found in the Lurmann mechanism than in CBIV due to the stronger contribution from the NO/RO2 channel in this mechanism. This resulted in a difference in the O3 tendency of a factor of 1.5. A major need in terms of future studies will be that of examining these same four mechanisms with a data set that enfolds observations in more polluted regions.
233

Studies of the electro-optical properties of liquid-crystal Fresnel lens based on cholesteric blue phase

Wang, Yu-yin 02 August 2010 (has links)
In this study, a liquid crystal Fresnel lens based on the cholesteric blue phase liquid crystals is proposed. Blue phases are liquid-crystalline phases that appear in a very small temperature range between a cholesteric phase and an isotropic phase. There are three types of blue phases; BP¢¹,BP¢º and BP¢». The BP¢¹ and BP¢º are characterized by a spatially periodic director field with lattice constants comparable to the wavelength of visible light. Because of the structural symmetry, blue phases are optically isotropic. In this study, the electro-optical properties of the BP¢º under different applied voltages are investigated. The results reveal that the Bragg reflection of the BPII has a red shift by increasing the applied voltage and a phase transition from BPII to cholesteric phase occurs at the high voltage regime (>100V). Based on the results, an electrically controlled blue phase Fresnel lens with polarization independence and high diffraction efficiency is demonstrated.
234

In situ chemical oxidation of TCE-contaminated groundwater using slow permanganate-releasing material

Wang, Sze-Kai 03 August 2011 (has links)
The purpose of this study was to use controlled release technology combining with in situ chemical oxidation (ISCO) and permeable reactive barrier (PRB) to remediate TCE-contaminated groundwater. In this study, potassium permanganate (KMnO4) releasing material was designed for potassium permanganate release in groundwater. The components of potassium permanganate releasing material included poly (£`-caprolactone) (PCL), potassium permanganate, and starch with a weight ratio of 2:1:0.5. Approximately 63.8% (w/w) of potassium permanganate was released from the material after 76 days of operation. The released was able to oxidize contaminant in groundwater. Results from the solid oxidation demand (SOD) experiment show that the consumption rate increased with increased contaminant concentration. TCE removal efficiency increased with the increased TCE concentration. The second-order rate law can be used to simulate the TCE degradation trend. In the column experiment, results show that the released MnO4- could oxidize TCE and TCE degradation byproducts when 95.6 pore volume (PV) of contaminated groundwater was treated. More than 95% of TCE removal can be observed in the column study. Although the concentration of manganese dioxide (MnO2) began to rise after 8.8 PV of operation, TCE removal was not affected. Results also show that low level of hexavalent chromium was detected (< 0.05 mg/L). Results from the scanning electron microscope (SEM) and energy-dispersive spectroscope (EDX) analyses show that the amounts of manganese and potassium in the materials decreased after the releasing experiment. Results indicate that the concentration of TCE and SOD need to be analyzed before the releasing materials are applied in situ. In the practical application, the releasing materials will not become solid wastes because they are decomposed after use. If this slow-releasing technology can be combined with a permeable reactive barrier system, this technology will become a more economic and environmentally-friendly green remedial system.
235

Experimental and computational investigations of therapeutic drug release from biodegradable poly(lactide-co-glycolide) (plg) microspheres

Berchane, Nader Samir 15 May 2009 (has links)
The need to tailor release-rate profiles from polymeric microspheres remains one of the leading challenges in controlled drug delivery. Microsphere size, which has a significant effect on drug release rate, can potentially be varied to design a controlled drug delivery system with desired release profile. In addition, drug release rate from polymeric microspheres is dependent on material properties such as polymer molecular weight. Mathematical modeling provides insight into the fundamental processes that govern the release, and once validated with experimental results, it can be used to tailor a desired controlled drug delivery system. To these ends, PLG microspheres were fabricated using the oil-in-water emulsion technique. A quantitative study that describes the size distribution of poly(lactide-coglycolide) (PLG) microspheres is presented. A fluid mechanics-based correlation that predicts the mean microsphere diameter is formulated based on the theory of emulsification in turbulent flow. The effects of microspheres’ mean diameter, polydispersity, and polymer molecular weight on therapeutic drug release rate from poly(lactide-co-glycolide) (PLG) microspheres were investigated experimentally. Based on the experimental results, a suitable mathematical theory has been developed that incorporates the effect of microsphere size distribution and polymer degradation on drug release. In addition, a numerical optimization technique, based on the least squares method, was developed to achieve desired therapeutic drug release profiles by combining individual microsphere populations. The fluid mechanics-based mathematical correlation that predicts microsphere mean diameter provided a close fit to the experimental results. We show from in vitro release experiments that microsphere size has a significant effect on drug release rate. The initial release rate decreased with an increase in microsphere size. In addition, the release profile changed from first order to concave-upward (sigmoidal) as the microsphere size was increased. The mathematical model gave a good fit to the experimental release data. Using the numerical optimization technique, it was possible to achieve desired release profiles, in particular zero-order and pulsatile release, by combining individual microsphere populations at the appropriate proportions. Overall, this work shows that engineering polymeric microsphere populations having predetermined characteristics is an effective means to obtain desired therapeutic drug release patterns, relevant for controlled drug delivery.
236

Calcium Signaling Mechanisms Mediate Clock-Controlled ATP Gliotransmission among Immortalized Rat SCN2.2 Cell Cultures

Burkeen, Jeffrey Franklin 2009 August 1900 (has links)
The hypothalamus is an integral part of the brain's regulation of mammalian physiology and behavior. Among many functions, this regulatory center activates the sympathetic nervous system, maintains appropriate body temperature, controls food intake, and controls release of hormones from the pituitary gland. Deep within the hypothalamus lie a paired cluster of cells, the suprachiasmatic nuclei (SCN), which function as the chief circadian pacemaker. The goal of the present thesis research was to study rhythmically controlled ATP gliotransmission. I used an immortalized SCN2.2 hypothalamic cell line to determine the mechanism by which ATP signaling is regulated in this context. Additionally, this research aimed to elucidate if clock-controlled ATP gliotransmission is fundamentally distinct from stimulus-evoked calcium-dependent mechanisms that regulate intercellular ATP signaling among astrocytes. In this thesis, I show that there are multiple ATP signaling mechanisms present among SCN2.2 cells. cAMP-dependent signaling mediates clock-controlled ATP accumulation but not stimulus-evoked ATP signaling. In addition, pharmacological studies suggest that disparate purinergic receptor-mediated mechanisms are involved in the regulation of clock-controlled versus stimulus-evoked ATP signaling. Rhythmic accumulation of ATP in SCN2.2 cultures is modulated by calcium-dependent processes. Peaks in ATP accumulation coincide with elevated mitochondrial calcium levels, while troughs in ATP accumulation coincide with periods of high cytosolic calcium levels, suggesting a possible mechanistic link between circadian shifts in intracellular calcium handling and ATP handling in SCN2.2 cells. Clock-controlled ATP accumulation in SCN2.2 cells is not a by-product of rhythmic cell cycle or rhythmic cell death. Overall, my research suggests that the ATP accumulation rhythm in SCN2.2 cells is likely an output of the biological clock, mediated by astrocytic calcium signaling processes, and not an output of cell division or cell death. Estimation of ATP accumulation in SCN2.2 cultures at peak time points suggests that clock-controlled ATP release is critical to the function of astrocytes in the mammalian brain, perhaps in the regulation of brain metabolism, the regulation of sleep/wake physiology, or the integration of both.
237

The Effects of Different Pain Control for Patients After Surgery¡GThe example of Patients in a Southern Regional Teaching Hospital

Tswei, Tsz-Hsuin 24 January 2006 (has links)
Abstracts: The purpose of the study was to compare the efficacy and cost between intravenous patient-controlled analgesia (PCA) with intramuscular (IM) analgesics for women in the first two days after surgery. The study included 200 patients who were assigned to receive PCA or intramuscular injections opioid during a period of 2 days after surgery. The PCA group included 124 patients and IM group had 76 patients. The data were collected using a structured questionnaires, patient chart review and hospital charge data. The several findings were observed in this study. 1. The pain level in the PCA group was significantly lower than in the IM group (P< 0.01). The PCA group had significantly greater satisfaction with pain control than those in IM group (p< 0.01). The influence of activity by pain in the IM group had significantly greater than those in PCA group (p< 0.05). 2. The incidence of skin itching in PCA group was significantly higher than in the IM group ¡]P< 0.01¡^.3. Cost per patient was higher for PCA group¡]NT$ 420.9¡Ó22.6¡^than IM group¡]NT$228.4¡Ó60.1¡^. In conclusion, PCA produced better pain relief, get better patient¡¦s satisfaction than conventional on-demand IM opioid injections but it was more expensive.
238

Development of Chirp-Controlled Pump-Probe Technique and Study of TeraHertz Radiation Enhancement

Liao, Li-Yuan 26 July 2006 (has links)
In this thesis, a home made chirp-controlled pump-probe measurement system has been developed and is used to explain possible mechanism of THz radiation enhancement under positive chirped incident pulse. The chirp-controlled pump-probe measurement system with temporal resolution of around 100 femtosecond and chirp parameter tuning from ¡V350 fs2 to +650 fs2 is demonstrated. Meanwhile, using chirp-controlled pump-probe measurement system, ultrafast dynamics of photogenerated carrier in low-temperature growth GaAs in different chirp by is characterized. The relaxation time of low-temperature growth GaAs in positive chirp pump pulse is 461fs and shorter than one, which is 497fs, in negative chirp pump pulse. The result is explained by the Pump-Dump process in negative chirp pump pulse and similar band-filling effect in positive chirp pump pulse.
239

Preparation Of Chitosan-polyvinylpyrrolidone Microspheres And Films For Controlled Release And Targeting Of 5-fluorouracil

Ozerkan, Taylan 01 September 2007 (has links) (PDF)
Controlled drug delivery systems deliver drugs at predetermined rates for extended periods. Although there are various types such as capsules, tablets etc, micro and nano spheres are the most commonly used systems. In this study, a set of chitosan-polyvinylpyrrolidone (CH-PVP) microspheres containing different amounts of polyvinylpyrrolidone as semi inter penetrating networks (semi-IPN) were prepared as controlled release systems. Emulsification method was applied for the preparation of microspheres and some of them were conjugated with a monoclonal antibody which is immunoglobulin G (IgG). CH-PVP films were also prepared by solvent casting method with the same composition as in the microspheres and, mechanical and surface properties of the films were examined. Prepared microspheres were characterized by SEM, stereo and confocal microscopes. Some microspheres were loaded with a model chemotherapeutic drug, 5-Fluorouracil (5-FU), and in-vitro release of 5-FU were examined in phosphate buffer solutions (pH 7.4, 0.01 M.) It was shown that for semi-IPN samples release was faster compared to pure CH samples and the total release was achived 30 days for CH:PVP-2:1, CH:PVP-3:1 semi-IPNs and CH microspheres and 27 days for CH:PVP-1:1 semi-IPN microspheres. The antibody conjugated microspheres were targeted to MDA-MB (human causasian breast carcinoma cancer cells and coculture cells in culture medium. For the CH-PVP films, it was obtained that as the amount of PVP increased, hydrophobicity as well as mechanical strength of the system was decreased.
240

Control of rhythmic output from the circadian clock in Neurospora crassa

Lewis, Zachary Austin 17 February 2005 (has links)
Circadian rhythms are visible as daily oscillations in biochemical, physiological, or behavioral processes. These rhythms are produced by an endogenous clock that maintains synchrony with the external environment through responses to external stimuli such as light or temperature. The clock, in turn, coordinates internal processes in a time-dependent fashion. Genetic and molecular analysis of the filamentous fungus Neurospora crassa has demonstrated that the products of the frequency (frq) and white-collar (wc-1 and wc-2) genes interact to form an interlocked feedback loop that lies at the heart of the clock in this fungus. This feedback loop, termed the FRQ/WC oscillator, produces a ~24h oscillation in frq mRNA, FRQ protein, and WC-1 protein. In turn, the FRQ/WC oscillator regulates rhythmic behavior and gene expression. The goal of this dissertation is to understand how rhythmic outputs are regulated by the FRQ/WC oscillator in Neurospora. To this end, we have taken a microarray approach to first determine the extent of clock-controlled gene expression in Neurospora. Here, we show that circadian regulation of gene expression is widespread; 145 genes, representing 20% of the genes we analyzed, are clock-controlled. We show that clockregulation is complex; clock-controlled genes peak at all phases of the circadian cycle. Furthermore, we demonstrate the clock regulates diverse biological processes, such as intermediary metabolism, translation, sexual development and asexual development. WC-1 is required for all light- and clock-regulated gene expression in Neurospora. We have shown that overexpression of WC-1 is sufficient to activate clock-controlled gene expression, but is not sufficient to induce all light-regulated genes in Neurospora. This result indicates that cycling of WC-1 is sufficient to regulate rhythmic expression of a subset of clockcontrolled genes. Conversely, a post-translational mechanism underlies WC-1 mediated light signal transduction in Neurospora. Finally, we have demonstrated the Neurospora circadian system is comprised of mutually coupled oscillators that interact to regulate output gene expression in the fungus.

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