Development of Advanced Materials Using Microwaves

Ph.DDOCTOR OF PHILOSOPH

Master of Science

thesisThe Residency Review Committee (RRC) requires that general surgery residents document their Surgical Intensive Care Unit (SICU) experiences. To satisfy these requirements we created a web based intranet log to make it easier for residents to track their patients and determine when these requirements were complete. A premium was put on usability to promote acceptance by surgical residents. A prototype web site was designed with input from an attending general surgeon. Three general surgery residents were selected to participate in the iterative design phase. They went through three iterations using a "think-aloud" method while performing tasks on the prototype web site. Each iteration led to improvements to the web site. In a comparison test, a group of seven medical students performed 14 typical web site tasks using both the prototype and the final versions. They were asked to complete a Questionnaire for User Interaction Satisfaction (QUIS) for each version. The time for completion of these tasks was also recorded. The user interaction satisfaction did not show any improvement (F(1,6)=0.13, p=0.912). Similarly, there was no improvement in times for delete and add tasks ( Delete F(1,5) = 0.949, p=0.375, Add F(1,5)=0.267, p=0.628 ); however, the time to complete edit tasks was faster for the final version of the web site (F (1,5)= 14.3, p=0.013). The primary reason for not detecting other differences between the two web sites is likely that the comparison study did not have sufficient power. This was suggested by the participants whose comments favored the final version over the prototype as well as a trend of consistently higher mean subset scores in the final version. The results indicate that differences may be seen when more complex tasks are completed (editing information) versus the two simpler tasks (adding or deleting a patient record in a web site). Future studies should focus on the impact of navigation strategies on speed and data warehouse approaches to creating the application. This study shows the benefits of using an iterative design approach to create a usable web site and demonstrates the importance of further research in the field of usability

Abundance And Ecological Significance Of The Clam Rangia Cuneata (Sowerby, 1831) In The Upper Barataria Estuary (Louisiana, USA)

We proposed that Rangia cuneata (Sowerby, 1831) is an important estuarine bivalve with ecological significance in three coastal lakes in Barataria Bay, Gulf of Mexico—Lake Cataouatche, Lake Salvador and Lac des Allemands. Our goals were to determine the abundance and distribution of Rangia in these lakes and to measure clearance times to elucidate its potential impacts on phytoplankton communities. The estimated average densities of R. cuneata in Lake Cataouatche, Lake Salvador, and Lac des Allemands were 63, 157, and 107 individuals m−2, respectively, which is 30% lower than that observed in nearby Lake Pontchartrain. The size of clams in Lake Salvador was between 4 and 50 mm, while individuals in Lake Cataouatche and Lac des Allemands were mostly \u3e20 mm. We postulate that a relatively infrequent large tropical storm transported the larvae from Lake Salvador to the other two lakes 1 year before our sampling to create this size difference. The clams were up to 99.9% of the total benthic biomass in Lake Salvador, 15.9% in Lake Cataouatche, and 40.0% in Lac des Allemands. The R. cuneata biomass values were between 16.2 and 27.6 g m−2 and the clearance times were 1.0–1.5 days. The clearance times are among the highest previously reported for coastal bivalve communities, which were from cooler climates. The results demonstrate that Rangia can be a critical part of the ecological processes in shallow water systems of the Gulf of Mexico

Size-Dependent Top-Down Control On Phytoplankton Growth By Microzooplankton In Eutrophic Lakes

We hypothesized that the grazing on phytoplankton by the microzooplankton community is size-dependent and, therefore, the top-down control on phytoplankton by microzooplankton community could be one possible mechanism explaining why small phytoplankton become less abundant than large phytoplankton in eutrophic waters. We tested this hypothesis using the dilution method to measure microzooplankton grazing rates and phytoplankton growth rates in the eutrophic waters of the Barataria estuary, southeastern Louisiana. Microzooplankton grazing rates on the slower growing, small phytoplankton (\5 lm) were higher than on the large phytoplankton ([20 lm) which had relatively faster growth rates. The proportional loss of the small, medium, large phytoplankton, and total phytoplankton community by microzooplankton grazing was 44, 53, 0, and 29%, respectively. The relative weakness of top-down grazing control on large phytoplankton by microzooplankton, and the relatively fast growth of large phytoplankton, may be why the average size of phytoplankton, whether isolated cells or colonies, tend to increase in these eutrophic waters and elsewhere

Daily smoking and lower back pain in adult Canadians: the Canadian Community Health Survey

Fahad Alkherayf1,2,3, Eugene K Wai4,5,6, Eve C Tsai1,3,4,6, Charles Agbi1,3,41University of Ottawa, Division of Neurosurgery, Ottawa, Ontario; 2University of Ottawa, Department of Clinical Epidemiology, Ottawa, Ontario; 3The Ottawa Hospital, Civic campus, Division of Neurosurgery, Ottawa, Ontario; 4The Ottawa Hospital, Civic Campus, Spine Unit Ottawa, Ontario; 5The Ottawa Hospital, Civic Campus, Division of Orthopedic Surgery, Ottawa, Ontario; 6The Ottawa Hospital Research Institute, Ottawa, Ontario, CanadaBackground: Lower back pain (LBP) is one of the primary causes of disability in the Canadian community. However, only a limited number of studies have addressed the association between daily smoking and LBP in Canada. Of the studies that have explored this association, many had small sample sizes and failed to control for confounders.Objective: The primary objective of the study was to determine if daily smoking is associated with an increased risk of having LBP. The secondary objectives were to assess the risk for LBP among occasional smokers and to determine the prevalence of LBP in relation to different covariates.Data and study design: Using the Canadian Community Health Survey (cycle 3.1) data, 73,507 Canadians between the ages of 20 and 59 years were identified. LBP status, smoking level, sex, age, body mass index (BMI), level of activity and level of education were assessed in these subjects.Methods: Stratified analysis and logistic regression analysis were used to detect effect modifications and to adjust for covariates. Population weight and design were taken into consideration.Results: The prevalence of LBP was 23.3% among daily smokers and 15.7% among non-smokers. Age and sex were found to be effect modifiers. The association between LBP and daily smoking was statistically significant in all ages and genders; this association was stronger for younger age groups. The adjusted odds ratio for male daily smokers aged 20 to 29 was 1.87 (95% CI = 1.62, 2.17); findings were similar for women. Occasional smoking slightly increased the odds of having back pain.Conclusion: Young Canadian daily smokers are at higher risk for LBP. This study also suggests a positive correlation between smoking dose and the risk of LBP. These findings indicate that smoking behavioral modification may have an impact on reducing back pain especially among young adults.Keywords: lower back pain, smoking, Canadian Community Health Survey, sex, adult Canadian

Oblique Angle Deposition of Germanium Film on Silicon Substrate

The effect of flux angle, substrate temperature and deposition rate on obliquely deposited germanium (Ge) films has been investigated. By carrying out deposition with the vapor flux inclined at 87° to the substrate normal at substrate temperatures of 250°C or 300°C, it may be possible to obtain isolated Ge nanowires. The Ge nanowires are crystalline as shown by Raman Spectroscopy.Singapore-MIT Alliance (SMA

Study of Stress Evolution of Germanium Nanocrystals Embedded in Silicon Oxide Matrix

Germanium (Ge) nanocrystals had been synthesized by annealing co-sputtered SiO₂-Ge in N₂ and/or forming gas (90% N₂ + 10% H₂) at temperatures ranging from 700 to 1000°C from 15 to 60 min. It was concluded that the annealing ambient, temperature and time have a significant influence on the formation and evolution of the nanocrystals. We also showed that a careful selective etching of the annealed samples in hydrofluoric solution enabled the embedded Ge nanocrystals to be liberated from the Si oxide matrix. From the Raman results of the as-grown and the liberated nanocrystals, we established that the nanocrystals generally experienced compressive stress in the oxide matrix and the evolution of these stress states was intimately linked to the distribution, density, size and quality of the Ge nanocrystals.Singapore-MIT Alliance (SMA

Organisational context and behavioural complexity affecting ambidextrous behaviours among SMEs

Purpose – The purpose of this paper is to examine the antecedents of exploitative and explorative behaviours and to give valuable insight into the role of ambidextrous behaviours in developing creativity and innovativeness among owner-managers in SMEs. Design/methodology/approach – A review of existing literature was carried out and drawing upon ownermanagers, a survey using structured questionnaires was carried out with a total of 183 useful responses received. The proposed model was analysed using SmartPLS v2.3.7. Findings – The empirical result suggests that behavioural complexity and organisational flexibility encourages exploitative and explorative behaviours, while ambidextrous behaviours encourage creativity and innovativeness. Rigidity, on the other hand, hinders the cultivation of ambidextrous behaviours. Originality/value – The paper entails useful implication by demonstrating that flexibility enables ownermanagers to reconcile competing demands and consequently, cultivate innovative outcomes. In this regard, business owner-managers must learn implicitly how to juggle these contradictory demands, suggesting an internal balancing mechanism independent of the organisational context and individual behavioural complexity. This paper suggests that cultivation of exploitative and explorative behaviours among ownermanagers is useful in encouraging ambidextrous behaviours among SMEs

Smart Nanoscopy: A Review of Computational Approaches to Achieve Super-Resolved Optical Microscopy

The field of optical nanoscopy , a paradigm referring to the recent cutting-edge developments aimed at surpassing the widely acknowledged 200nm-diffraction limit in traditional optical microscopy, has gained recent prominence & traction in the 21st century. Numerous optical implementations allowing for a new frontier in traditional confocal laser scanning fluorescence microscopy to be explored (termed super-resolution fluorescence microscopy ) have been realized through the development of techniques such as stimulated emission and depletion (STED) microscopy, photoactivated localization microscopy (PALM) and stochastic optical reconstruction microscopy (STORM), amongst others. Nonetheless, it would be apt to mention at this juncture that optical nanoscopy has been explored since the mid-late 20th century, through several computational techniques such as deblurring and deconvolution algorithms. In this review, we take a step back in the field, evaluating the various in silico methods used to achieve optical nanoscopy today, ranging from traditional deconvolution algorithms (such as the Nearest Neighbors algorithm) to the latest developments in the field of computational nanoscopy, founded on artificial intelligence (AI). An insight is provided into some of the commercial applications of AI-based super-resolution imaging, prior to delving into the potentially promising future implications of computational nanoscopy. This is facilitated by recent advancements in the field of AI, deep learning (DL) and convolutional neural network (CNN) architectures, coupled with the growing size of data sources and rapid improvements in computing hardware, such as multi-core CPUs & GPUs, low-latency RAM and hard-drive capacitie

Charge storage in nanocrystal systems: Role of defects?

Wet thermal oxidations of polycrystalline Si₀.₅₄Ge₀.₄₆ films at 600°C for 30 and 50 min were carried out. A stable mixed oxide was obtained for films that were oxidized for 50 min. For film oxidized for 30 min, however, a mixed oxide with Ge nanocrystallites embedded in the oxide matrix was obtained. A trilayer gate stack structure that consisted of tunnel oxide/oxidized polycrystalline Si₀.₅₄Ge₀.₄₆/rf sputtered SiO₂ layers was fabricated. We found that with a 30 min oxidized middle layer, annealing the structure in N₂ ambient results in the formation of germanium nanocrystals and the annealed structure exhibits memory effect. For a trilayer structure with middle layer oxidized for 50 min, annealing in N₂ showed no nanocrystal formation and also no memory effect. Annealing the structures with 30 or 50 min oxidized middle layer in forming gas ambient resulted in nanocrystals embedded in the oxide matrix but no memory effect. This suggests that the charge storage mechanism for the trilayer structure is closely related to the interfacial traps of the nanocrystals.Singapore-MIT Alliance (SMA