Dissolved organic nitrogen (DON) represents a major pool of fixed, reactive nitrogen in marine systems. It is now recognized that this pool can support primary production and the ability of some algal species to exploit DON compounds as sources of Nitrogen (N) may indicate that specific DON components can exert selective pressure on the composition of the phytoplankton community. In this study the ability of monocultures of ecologically-relevant algal species from the English Channel (Emiliania huxleyi, Micromonas pusilla, Alexandrium minutum and Chaetoceros peruvianus) to grow with DON as the only N source was examined using different artificial media. Among the two tested artificial seawater recipes, Aquil* was preferred as it contained lower micronutrient concentrations, and gave better growth results for all used species. In order to constrain the DON uptake to algae alone, a method for bacterial removal was tested using antibiotic additions. Both Slocombe antibiotic mixture (Cefotaxime-Carbenicillin-Kanamycin-AugmentinTM) and Penicillin-Streptomycin-Neomycin used were effective and not toxic to the algae. Incubation with the antibiotic up to 48 hours and a transfer period into antibiotic-free medium after 72 hours proved to be effective. However, the treatment removed bacteria in A. minutum cultures only; further treatment would be required for the other species to be cultured axenically. The ability to use DON was tested for the above mentioned species using the amino acid L-Arginine (ARG) as the sole N source, and growth was compared with nitrate-containing cultures of the same species. All the selected species grew in both NOᴈ‾ and in ARG, reaching lower final densities when incubated with ARG, although these were not significant. This study has shown that E. huxleyi, A. minutum, M. pusilla and C. peruvianus can grow on organic N, either by direct or indirect uptake, and develop comparable biomasses to species using inorganic N. Both C. peruvianus and M. pusilla cultures contained dissolved ammonium at the end of the experimental period, indicating potential indirect use by the algae of organic N converted to inorganic N by bacteria. A. minutum grew in the presence of ARG along with the cosmopolitan E. huxleyi; N-demand estimates, based on the molar concentration of N-ARG consumed, correlated with the final cell density, indicating that the species did not develop on inorganic N produced from ARG mineralisation, but directly on the ON substrate. Since A. minimum has been linked to harmful algal blooms, and E. huxleyi contributes significantly to oceanic CaCOᴈ deposition, their ability to utilise DON has environmental consequences in addition to the oceanic N-budget. Climate change scenarios predict both episodic conditions of elevated rainfall and extended periods of dry conditions leading to variable riverine inputs to coastal areas, altered nitrogen to phosphorus (N:P) ratios, and changes in the inorganic to organic balance of the nutrient pools. Organic N can constitute up to 69 % of the total N pools, respectively, making it crucial, to understand the cycling of this fraction in coastal waters, and how changes in the composition of nutrient pools could impact on marine ecosystem function and health.

There is growing concern that many children in Britain do not take sufficient exercise to benefit cardiovascular health. This is supported by extensive evidence advocating the importance of regular physical activity for lifelong health and well-being, and is of particular relevance in Scotland given it's notorious record of adult coronary heart disease death. This study examined aspects of fitness and physical activity in groups of Edinburgh school children, aged between 13 and 14 years. A three stage investigation was adopted: Phase One: A repeated measures, same subject design was used to examine the reliability and validity of selected measures (20m shuttle run test, peak oxygen uptake (V02 Peak), and anthropometric measures). Thirty three children (15 boys, 18 girls) performed each test on 3 separate days. Anthropometric measures showed strong reliability (r > 0.94, n=33) whilst reliability for the treadmill test ofV02 peak and shuttle run performance was lower (r=0.89 and r=0.79 respectively). Multiple regression analysis yielded a new equation for predicting V02 peak for children. This age specific prediction equation incorporated shuttle run performance in conjunction with skinfold thickness measures (Boys, R2=0.64 SEE=3.46; Girls, R2=0.79, SEE=2.81). Repeat testing was also recommended. Phase Two: An evaluation of methods of heart rate data analysis to assess physical activity in children. Twenty eight children (14 boys, 14 girls) wore continuous heart rate monitors (polar Electro PE4000, Finland) over a period of 7 days (Monday to Sunday), mean duration 737 (+/-55) mins/day. A detailed 7 day self report activity diary was also completed. Variability of heart rate measures was high (R=0.10-0.30), and it was noted that using data for just 4 days or less resulted in considerable underestimation of total weekly activity levels (44-100% error). If activity levels are to be compared against current recommendations, researchers must endeavour to achieve weekly rather than daily estimates of activity. Evaluation of methods of heart rate data analysis showed good correlation between heart rate activity indices and reported seven day activity. For boys strongest correlation was achieved using the number of 5 minute periods with HR > 139 b.min"l and the number of 5 minute periods with HR > 50% heart rate reserve (r=0.80, n=14). Total activity time was similar for both males and females but girls engaged in fewer sustained bouts of activity (>5 minutes) and a better correlate with activity in females was achieved using the total number of elevated heart rates (total HR > 50% heart rate reserve, r=0.64, n=14). Phase Three: A cross sectional survey was conducted to investigate standards of aerobic fitness and patterns of physical activity in groups of Edinburgh school children. Height, weight, skinfold thickness, shuttle run performance and physical activity (assessed by heart rate monitoring and activity diary) were recorded in a sample of 91 children (44 Boys, 47 Girls). Overall, males performed significantly better on the shuttle run test (t=5.4, df=88, p < 0.05), had higher predicted peak oxygen uptake (t=5.6, df=87, p < 0.05), and engaged in more bouts of moderate to vigorous activity than females. Seventy percent of boys and 50% of girls fulfilled current physical activity guidelines. Most activities were school based (131 mins per week as compared to 85 mins per week of out of school activities). Activity tended to be sporadic with active days interspersed with inactive days (mean 3.2 +/·1.6 days per week). After school activities specifically targeting young girls should be promoted.

Candida albicans is an opportunistic fungal pathogen. It is the fourth leading cause of nosocomial infections and can endanger immunocompromised patients. Candida has the ability to form biofilms on plastic medical devices, such as catheters and central nervous system shunts. Two clinical isolate series were profiled using a number of phenotyping assays comprising in vivo, ex vivo, and in vitro tests. These tests shed light on host-pathogen relations as well as offer potential information useful in the treatment of these infections. Fluconazole, an antifungal, is the first line of treatment for fungal infections. The incidence of fluconazole-resistant infections is increasing annually, and there are not many other drugs available to treat infections. In 2013, Fazly et al. discovered the drug Filastatin, which prevents adhesion and filamentation of Candida albicans. In our study, two screens were performed to identify the target of Filastatin. Because there is no complete knockout library for Candida, an available, partial knockout library was screened. This library is enriched for transcription factors. We screened for regulators of biological pathways that may be important for adhesion and filamentation in Candida albicans, to identify potential Filastatin targets. The iron-uptake pathway was chosen as the focus for the remainder of this study.

Background: Eating disorder (ED) researchers continue to explore the effectiveness of e-therapy in improving symptoms and its treatment acceptability, however issues relating to poor uptake, adherence and dropout pose a challenge. Within this portfolio, the systematic review aimed to explore adherence to e-therapy for the treatment of ED, specifically exploring rates and predictors of uptake, completion, and dropout from randomised controlled trials (RCT) of ED e-therapy. The empirical project aimed to explore in-depth symptom change for ED cases engaged in blended internet-based cognitive behavioural therapy (ICBT) and face-to-face ED input. Acceptability of blended input was also explored. Methods: For the systematic review, literature searches were undertaken in March and September 2017 across EMBASE, PsycINFO, MEDLINE, Ovid and Cochrane Central Register of Controlled Trials (CENTRAL) and ProQuest databases. Key papers were assessed against five quality criteria (random assignment to groups, blinding to treatment allocation, quality of content, level of contact, sample size with sufficient power). Using a retrospective case series design, the empirical project explored changes over time of ED, anxiety, depression, quality of life (QoL), motivation for change, overall psychological functioning and clinician-rated/patient-rated improvement. Standardised health assessment measures captured symptoms over multiple time-points, and data was analysed using t-tests, multi-level modelling (MLM) and visual analysis. Acceptability of treatment was tentatively explored using an open feedback questionnaire. Results: Systematic review results identified intervention (content, acceptability, delivery method/location), participant (nature of symptoms, BMI, education, prior therapy, personality, views on e-therapy) and therapist-related factors (therapeutic support) were indicated in predicting uptake, completion and dropout across ED e-therapy. In the empirical project, study findings were inconclusive regarding symptom change attributable to blended input. Model fit improved when severity of ED symptoms predicted overall psychological functioning and patient-rated improvement over time, however findings were non-significant - potentially due to the study being underpowered. Conclusions: Promising evidence exists for ED e-therapy as an acceptable treatment option, however understanding which content nurtures engagement best is needed. Further research is needed into the factors predicting ED blended treatment outcome.

Sulfolane (tetrahydrothiophene 1,1-dioxide, C4H8O2S) is a highly water-soluble, non-ionizable, organic compound used along with diisopropanolamine in the SulfinolTM process to remove hydrogen sulfide from natural gas. Sulfolane has been identified in wetland vegetation near a sour gas processing facility in Alberta, Canada, and extensive uptake of sulfolane by cattails has also been demonstrated in a laboratory environment. Consequently, it has been suggested that plants could play an important role in the natural attenuation of sulfolane in contaminated wetlands. This assumes that the sulfolane is metabolized and/or sequestered in the plant and not released back into the environment during winter dieback. To address the potential release issue, individual cattails (Typha latifolia) were grown hydroponically in 500-mL glass containers containing one of three initial sulfolane concentrations (8, 40, or 200 mg/L) for a specified duration (7 to 28 days). Half the cattails were used to quantify uptake as a function of time and exposure concentration and the other half were used to evaluate the potential release of sulfolane into the hydroponic solution. Non-exposed cattails and non-planted systems containing sulfolane served as controls. The cattails used to evaluate the potential release of sulfolane were frozen directly in their individual containers at the end of the appropriate exposure period. After being frozen for a minimum of 72 hours, the containers were thawed and the amount of sulfolane released was monitored. At the end of the 28-day uptake period, sulfolane leaf tip tissue concentrations as high as 3600, 1050, and 165 mg/kg dry weight were found for the cattails initially exposed to 200, 40, and 8 mg/L sulfolane, respectively. The percentage of sulfolane subsequently released by the cattails after the freeze-thaw treatment declined as a function of the duration exposed. The percentages of sulfolane released measured in the water after 72 hours in addition to the plant tissue extractions were 71%, 54%, 27%, and 12% for the 40 mg/L concentration at 7-, 14-, 21-, and 28-day exposure periods, respectively. Other concentrations showed the same decreasing trend for increasing exposure periods. The declining release as a function of time suggests metabolism and/or sequestration of the sulfolane within the plant. The significant uptake and limited release of sulfolane from mature plants indicate that wetland plants could play an important role in its natural attenuation.

This thesis describes an investigation of the effects of vitamin A deficiency on gut function, The central hypothesis to be tested was that acute vitamin A deficiency affects glucose uptake from the small intestine- The hypothesis was tested using a system involving perfusion of isolated segments of the small intestine in the anaesthetized rat. The system was used to study effects on glucose uptake under steady-state conditions. In the initial part of the study, experiments were diverted towards setting up the system for measuring steady-state uptake, and determining the relative contributions of active uptake and diffusion. Phenol red was found to be a reliable non-absorbable marker for determining net water movement. Phlorizin, generally at 1 mmol/L, was used as a competitive (reversible) inhibitor of active uptake. It is difficult however to confirm complete inhibition of active uptake by phlorizin because of the limited solubility of the inhibitor. The kinetics of glucose uptake f ram intra-luminal maltose were found to be, in general, not significantly different from those applying to the uptake of glucose from an equivalent glucose solution. Maltase activity in the perfused gut segment was found to be sufficient to hydrolyse most of the maltose (80 per cent or more) in the solution being perfused, a much greater proportion than was absorbed. Glucose absorptive capacity, measured on an intestinal dry weight basis, was greatest in the duodenum and progressively less in the jejunum and ileum. The rate of water uptake f ran the gut was increased by the presence of glucose in the lumen, and was linked to glucose uptake as shown by the inhibition of water uptake by phlorizin. Uptake of glucose by solvent drag was demonstrated by showing an increased rate of glucose uptake when the rate of water uptake was increased by perfusing a solution of reduced osmotic pressure. In the experiment a low intra-luminal glucose concentration was used to preclude net uptake by diffusion and active uptake was blocked with phlorizin. This process was further investigated using streptozotocin-diabetic rats in which the diabetes establishes a hyperosomotic blood with hyperglycaemia. Uptake by solvent drag was more obvious in diabetic animals. A back-diffusion (exsorption) of glucose from the tissues to the lumen was also shown; the rate being proportional to plasma glucose concentration. Vitamin A deficiency was established in weanling rats after 6-7 weeks feeding on a diet based on wheat starch, coconut oil, and casein washed with hot ethanol, together with vitamins and minerals. The vitamin A deficiency led to classic eye signs and was reversed by the addition to the diet of retinoic acid (5 g/g diet). Vitamin A deficiency decreased intestinal mucus production (dry weight) but had no detectable effect on the histology of the villous epithelium as shown under the light microscope. Using perfusion experiments it was shown that vitamin A deficiency had no significant effect on the rate of active uptake of glucose, but that deficiency increased the rate of passive uptake.

Fluorescent analogs of biomolecules have been known as useful probes to study the structure, conformations and dynamics of cellular processes. These probes are more ideal than fluorescent labeled probes, as fluorescent analog probes retain the shape, size, conformation, and recognition element of the natural substrate, while giving useful intracellular information about detection and dynamics of biomolecules. The monoamine neurotransmitters control the central and periphery nervous systems. Serotonin (5-HT), in particular, is a versatile chemical messenger responsible for a multitude of biological processes, such as regulation of emotion, vasoconstriction, and bone metabolism. The study of serotonergic complex pathways is vital and essential in drug discovery for the diseases that result from the depletion and deregulation of serotonin in synapse. The extracellular concentration of serotonin is controlled by several transporters, most preferably the serotonin transporter (SERT). Selective serotonin reuptake inhibitors (SSRIs), along with dual- and triple-acting inhibitors, affect SERT and hence 5-HT in depression and related diseases. In this present investigation, firstly, a set of fluorescent analogs of neurotransmitter probes based on ethylamino-functionalized substrates were successfully designed and these fluorescent probes were synthesized by convenient synthetic methods. Secondly, optical properties of these fluorescent probes were investigated in organic medium, in order to test their suitability for screening and imaging the biological cells. Finally, their uptake was examined in the murine osteocytic cell line, MLO-Y4, platelets of blood sample and HEK-293 cells expressing the dopamine transporter (DAT), norepinephrine transporter (NET) or SERT. The fluorescent probes targeting bone-derived cell line expressing 5-HTT provide useful information in understanding the dynamics of 5-HT regulation with respect to SSRI treatment. A novel fluorescent analog of 5-HT probe was developed that may be utilized to study 5-HTT function in the context of 5-HT uptake or regulation in cell culture, tissue explants, or even in vivo.

Attention worldwide has been placed towards reducing the global carbon footprint. To this end the scientific community has been involved in improving many of the available methods of carbon capture and storage (CCS). CCS involves scrubbing flue gases of greenhouse gases and safely storing them deep underground. MOFs, a family of functionally tunable three dimensional nanoporous frameworks, have been shown to adsorb gases with great selectivity and capacity. Investigating these frameworks using computational simulations, although faster than in-lab synthetic methods, involves a tedious and meticulous input preparation process which is subject to human error. This thesis presents Dave's Occupancy Automation Package (DOAP),a software which provides a means to automatically determine the gas uptake of many three dimensional frameworks. By providing atomic coordinates for a unit simulation cell, the software acts to performs the necessary calculations to construct and execute a Grand Canonical Monte Carlo simulation, determining the gas uptake in a metal organic framework. Additionally an analysis of different convergence assessment tests for describing the end point of the GCMC simulation is presented.

Lead is an omnipresent pollutant, and its contamination in natural waters is an issue of current regulatory concern throughout the world including Canada. The free divalent ion of lead (Pb2+) is considered to be the most bioavailable and toxic form of lead. Pb2+ is known to be a calcium antagonist in vertebrates including fish. It is believed that lead causes toxicity to freshwater fish primarily by disrupting ionic homeostasis both during acute and chronic waterborne exposure. Lead can also potentially act as a respiratory toxicant since it is known to impair hemoglobin synthesis in both vertebrates. To date, the mechanistic underpinnings of lead accumulation and toxicity in aquatic invertebrates are not well understood, particularly during acute exposure. Therefore, the main objectives of the present study were in two folds: (i) to investigate the mechanisms of waterborne lead uptake, and (ii) to understand the physiological basis of lead toxicity during acute exposure. I used freshwater crustacean, <i>Daphnia magna</i>, as a model freshwater invertebrate species for my study. <i>Daphnia</i> are known to be quite sensitive to metals and widely used as a model species for toxicity assessments. The results of my study suggest that lead inhibits waterborne Ca2+ uptake in <i>Daphnia</i> in a concentration dependent manner, and this inhibition occurs predominantly through a direct competitive interaction. The entry of waterborne Pb2+ in <i>Daphnia</i> likely occurs via both lanthanum-sensitive and verapamil-sensitive epithelial calcium channels. Moreover, my results also indicate that acute waterborne lead exposure severely disrupts both Ca2+ and Na+ uptake from water, which are concomitant with the increase in the lead body burden in <i>Daphnia</i>. Interestingly however, acute exposure to lead does not affect the rate of oxygen consumption in <i>Daphnia</i>, indicating no acute respiratory toxicity of lead. Overall, it appears that lead acts as an ionoregulatory toxicant to <i>Daphnia</i> during acute waterborne exposure.

Lead is an omnipresent pollutant, and its contamination in natural waters is an issue of current regulatory concern throughout the world including Canada. The free divalent ion of lead (Pb2+) is considered to be the most bioavailable and toxic form of lead. Pb2+ is known to be a calcium antagonist in vertebrates including fish. It is believed that lead causes toxicity to freshwater fish primarily by disrupting ionic homeostasis both during acute and chronic waterborne exposure. Lead can also potentially act as a respiratory toxicant since it is known to impair hemoglobin synthesis in both vertebrates. To date, the mechanistic underpinnings of lead accumulation and toxicity in aquatic invertebrates are not well understood, particularly during acute exposure. Therefore, the main objectives of the present study were in two folds: (i) to investigate the mechanisms of waterborne lead uptake, and (ii) to understand the physiological basis of lead toxicity during acute exposure. I used freshwater crustacean, <i>Daphnia magna</i>, as a model freshwater invertebrate species for my study. <i>Daphnia</i> are known to be quite sensitive to metals and widely used as a model species for toxicity assessments. The results of my study suggest that lead inhibits waterborne Ca2+ uptake in <i>Daphnia</i> in a concentration dependent manner, and this inhibition occurs predominantly through a direct competitive interaction. The entry of waterborne Pb2+ in <i>Daphnia</i> likely occurs via both lanthanum-sensitive and verapamil-sensitive epithelial calcium channels. Moreover, my results also indicate that acute waterborne lead exposure severely disrupts both Ca2+ and Na+ uptake from water, which are concomitant with the increase in the lead body burden in <i>Daphnia</i>. Interestingly however, acute exposure to lead does not affect the rate of oxygen consumption in <i>Daphnia</i>, indicating no acute respiratory toxicity of lead. Overall, it appears that lead acts as an ionoregulatory toxicant to <i>Daphnia</i> during acute waterborne exposure.