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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.
351

The Effects of Playing Exergames on Energy Expenditure

Kirkwood, Demetrice 01 December 2011 (has links)
The purpose of this study was to assess the performance, ratings of perceived exertion, metabolic responses, and energy expenditure as individuals participated in interactive video game play. There were 14 participants that participated in the study, whose age was 20.1 ± 1.64 years of age. Participants completed a maximal aerobic test to exhaustion (VO2max test), and then 30 minute testing session on both the Kinect Adventures (K) and Wii Fit Plus game. Data were analyzed using a dependent t-test and one-way ANOVA. Significance was accepted at P ≤ 0.05. Energy expenditure and RPE were significant in both exergames interactive game play P=0.044 and P < 0.05, respectively. In addition, heart rate (P=0.001) and performance during exergame play P=0.00015 were of significance in the Xbox Kinect and Wii Fit Plus. In conclusion, we found that individuals participating on the exergame Xbox Kinect expends more calories and work at a higher intensity than the Wii Fit Plus, thus justifying an alternative way to participate in physical activity via exergames. As an alternative way to exercise, individuals can meet the daily requirements of energy expenditure of moderate intensity, which is 150-400 kcals.
352

Characterization of the HEME Uptake Pathway Proteins from Streptococcus Pyogenes and Corynebacterium Diphtheriae

Akbas, Neval - 25 June 2012 (has links)
In Streptococcus pyogenes, the protein SiaA (HtsA) is part of a heme uptake pathway system and involved in heme transfer from Shp to the ABC transporter. SiaA mutants, in which alanine replaces the axial histidine (H229) and methionine (M79) ligands, as well as a lysine (K61) and cysteine (C58) located near the heme propionates, are reported. Studies on a mutant of a cysteine expected to be at a distance from the propionates (C47A) are also reported. The coordination state and spin state of the selected mutants were determined via Resonance Raman studies. The pKa values of mutants ranged from 9.0 to 9.4, which were close to the pKa of the WT SiaA (9.7). The midpoint reduction potential of lysine (K61A) mutant was determined by spectroelectrochemical titration to be 61 ± 3 mV vs. SHE, similar to the WT protein (68 ± 3 mV). The addition of guanidinium hydrochloride resulted in protein denaturation that could show more than one process and occurred over days. The ease of protein unfolding was directly related to the extent of interaction of the residues with the heme: changes in the axial ligands resulted in far greater changes in heme protein stability than changes in the residues near the heme propionates. The causative agent of diphtheriae, Corynebacterium diphtheriae, imports heme via an ABC uptake transporter. In this research, two of the five proteins in the heme uptake pathway of C. diphtheriae were studied. These proteins were HmuT, lipoprotein component of the ABC transporter, and HtaA, the heme receptor. UV-visible spectroscopy and fluorescence spectroscopy showed that HmuT protein as isolated bound a porphyrin, rather than heme. Electrospray ionization mass spectrometry (ESI-MS) studies suggested that two tetrapyrroles were bound. To assess stability of this protein towards heme release, thermal denaturation studies were performed. For HtaA, UV-visible and fluorescence spectroscopy also showed the protein as isolated was also bound a porphyrin, rather than heme. Homology studies showed that HtaA protein is quiet distant from homologous heme uptake proteins and could be a member of novel heme binding domain family.
353

The validity of a one-stage submaximal treadmill protocol to estimate maximal oxygen uptake in overweight males and females

Sheffield, Carrie A. 03 June 2011 (has links)
The purpose of this study was to determine the validity of the Ebbeling one-stage submaximal treadmill protocol to estimate maximal oxygen uptake in overweight males and females. Forty-five male and females (36.5±10.9 years; 170.2±9.9 cm; 77.9±9.0 kg) were categorized into overweight groups using a BMI of 25-29.9 kg/m2. The subjects performed a submaximal protocol that consisted of one 4-minute stage with individualized speeds of 2.0-4.5 mph at 5% grade and subsequently performed a maximal exercise test. There were significant relationships between observed and estimated VO2max for males (r=.796), females (r=.426), and gender combined (r=.844). There was an underestimation in the estimation of VO2max in the present study when comparing males (10%), females (26%) and gender combined (17%) subjects. The results indicated that a body mass index between the values of 25-29.9 kg/m2 did create a difference in estimating VO2max in the present study when comparing that to Ebbeling et al. (1991).Ball State UniversityMuncie, IN 47306 / School of Physical Education
354

High-Yield Synthesis and Applications of Anisotropic Gold Nanoparticles

Vigderman, Leonid 16 September 2013 (has links)
This work will describe research directed towards the synthesis of anisotropic gold nanoparticles as well as their functionalization and biological applications. The thesis will begin by describing a new technique for the high-yield synthesis of gold nanorods using hydroquinone as a reducing agent. This addresses important limitations of the traditional nanorod synthesis including low yield of gold ions conversion to metallic form and inability to produce rods with longitudinal surface plasmon peak above 850 nm. The use of hydroquinone was also found to improve the synthesis of gold nanowires via the nanorod-seed mediated procedure developed in our lab. The thesis will next present the synthesis of novel starfruit-shaped nanorods, mesorods, and nanowires using a modified nanorod-seed mediated procedure. The starfruit particles displayed increased activity as surface-enhanced Raman spectroscopy (SERS) substrates as compared to smooth structures. Next, a method for the functionalization of gold nanorods using a cationic thiol, 16-mercaptohexadecyltrimethylammonium bromide (MTAB), will be described. By using this thiol, we were able to demonstrate the complete removal of toxic surfactant from the nanorods and were also able to precisely quantify the grafting density of thiol molecules on the nanorod surface through a combination of several analytical techniques. Finally, this thesis will show that MTAB-functionalized nanorods are nontoxic and can be taken up in extremely high numbers into cancer cells. The thesis will conclude by describing the surprising uptake of larger mesorods and nanowires functionalized with MTAB into cells in high quantities.
355

A Study of the Mobility of Silver Ions in Chitosan Membranes

Lin, Elaine Yi-Hua January 2007 (has links)
Chitosan membrane has found applications in biomedical, wastewater treatment, and petrochemical fields that involve the use of silver ions (Ag+). However, mobility of Ag+ in chitosan membranes has seldom been studied. In this study, transport properties of Ag+ in chitosan membranes are studied in-depth, to determine diffusivity coefficient, permeability coefficient, and sorption uptake of Ag+ in chitosan. All parameters are evaluated based on the influence of feed concentration, membrane thickness and operating temperature. The diffusivity is determined from the time lag obtained from transient diffusion experiments. The permeability is determined from the steady state of permeation experimentally. The diffusivity and corresponding permeability coefficients of Ag+ in chitosan range from to 2.0 10-7 (cm2/s) and from 6.6 10-8 to 2.0 10-7 {mol m/[m2 s (mol/L)]}, respectively, over the conditions tested. Temperature dependencies of these two parameters are found to follow the Arrhenius relationship. Sorption uptake of the silver salt in chitosan correlates well with the Langmuir isotherm. Also determined from the sorption tests are degree of membrane swelling at different concentrations. This information allows diffusivity coefficients to be determined from the steady state permeation rate. These values of diffusivity are compared with that obtained using the time lag method.
356

Moisture Response of Wall Assemblies of Cross-Laminated Timber Construction in Cold Canadian Climates

Lepage, Robert January 2012 (has links)
Wood is a highly versatile renewable material (with carbon sequestering properties), that is light in weight, has good strength properties in both tension and compression while providing good rigidity and toughness, and good insulating properties (relative to typical structural materials). Engineered wood products combine the benefits of wood with engineering knowledge to create optimized structural elements. Cross-laminated timber (CLT), as one such engineered wood product, is an emerging engineering material which provides great opportunities for the building industry. While building with wood has many benefits, there are also some concerns, particularly decay. Should wood be exposed to elevated amounts of moisture, rots and moulds may damage the product or even risk the health of the occupants. As CLT panels are a relatively new engineered wood product, the moisture characteristics have yet to be properly assessed. Consequently, the amount of decay risk for CLT in building applications is unknown, and recommended protective actions during design construction and operation have yet to be determined. The goal of this research was to determine the moisture durability of CLT panels in wall assemblies and address concerns related to built-in construction moisture. The approach used to address the problem was to first determine select moisture properties of CLT panels through experimental approaches, and then use the results to calibrate a hygrothermal model to quantify the risks of wall assemblies. The wall assemblies were simulated in six different cities across Canada, representing a range of climates: Vancouver, B.C., Edmonton, A.B., Winnipeg, M.B., Ottawa, O.N., Québec City, Q.C., and St. John, New-Brunswick. The risks associated with moisture exposure during construction are also considered in the simulations. The experimental phase of the research was limited to moisture uptake tests. These tests were utilized to determine the liquid water absorption coefficient for four different types of full scale panels (2’x2’) and 12 clear wood samples. The panels were either made of 5-ply of Western-SPF, Eastern-SPF, Hemlock-Fir, or 3-ply of a generic softwood provided by a European CLT manufacturer; the clear samples were all cut from the same nominal 2x6 SPF-grade lumber. The panels were installed in a drying rack and gravimetrically tracked to assess the drying rates of the panels. Finite resources precluded more thorough material testing, but a parametric study was conducted to determine the relative impact of the missing material data on the final simulation results. In the hygrothermal simulations, four main wall assembly types were considered- those with either exterior or interior insulation, and those using either vapour permeable or impermeable air-water barriers. Various types of insulation and vapour control were also modelled. The simulations were run for a variety of interior relative humidities. The metric for comparison between the simulations was the water content of a 4mm thin layer on the extreme lamina of a CLT panel system. The results of the simulation suggest that vapour impermeable membranes, when install on dry CLT panels (less than 14% M.C.) do not pose moisture risks in any of the climates considered. However, when high levels of construction moisture is considered, only vapour permeable membranes controlled moisture risks by allowing the CLT panel to dry both to the interior and to the exterior.
357

Optimal seeding rates for organic production of field pea and lentil

Baird, Julia 30 August 2007 (has links)
There are no seeding rates established for organic production of field pea and lentil in Saskatchewan and organic producers must rely upon rates recommended for conventional production of these crops. These seeding rates may not be suitable for organic production as the two systems differ in the use of inputs and in pest management. The objectives of this study were to determine an optimal seeding rate for organic production of field pea and lentil in Saskatchewan considering a number of factors, including yield, weed suppression, soil nitrogen (N) and phosphorus (P) concentrations, soil water storage, colonization of crop roots by arbuscular mycorrhizal fungi (AMF), plant P uptake, and profitability. A field experiment was conducted to determine the optimal seeding rates of field pea and lentil. Field pea seeding rates were 10, 25, 62, 156 and 250 plants m-2 and lentil seeding rates were 15, 38, 94, 235 and 375 plants m-2. Sites were established at Vonda, Vanscoy and Delisle, SK using a randomized complete block designs with summerfallow and green manure treatments included for each crop. Seed yield increased with increasing seeding rate for both crops, up to 1725 kg ha-1 for field pea and 1290 kg ha-1 for lentil. Weed biomass at physiological maturity decreased with increasing seeding rate for both crops. In field pea, weeds were reduced in weight by 68%, while lentil reduced weed biomass by 59% between the lowest and highest seeding rates. <p>Post-harvest soil phosphate-P levels did not change consistently between treatments, indicating that there was no trend in soil P concentration with seeding rate. Post-harvest soil inorganic N, however, was higher for the summerfallow and green manure treatments than for the seeding rate treatments in both crops. Inorganic N was higher at some sites for the highest two seeding rates in field pea. Soil water storage following harvest was not affected by treatment.<p>Colonization of crop roots by AMF increased for lentil with increasing seeding rate, but the same trend was not observed in field pea. A growth chamber experiment to study the rate of colonization of field pea between 10 and 50 d after emergence did not show any differences in AMF colonization between seeding rates. Colonization levels were high (70 to 85%) for both crops in both the field and growth chamber. Arbuscular mycorrhizal fungi colonization and seeding rate had no effect on plant P concentration for either field pea or lentil. Both crops became increasingly profitable as seeding rate increased. Field pea reached a maximum return at 200 plants m-2 and lentil return increased to the highest seeding rate of 375 plants m-2. Organic farmers should increase seeding rates of these crops to increase returns and provide better weed suppression.
358

Nutrient uptake by hybrid poplar in competition with weed species under growth chamber and field conditions using the Soil Supply and Nutrient Demand (SSAND) model

Singh, Bachitter 06 February 2008 (has links)
Success of hybrid poplar plantations will rely on the efficient management of nutrients and weeds. Relatively little is known about the root uptake characteristics of hybrid poplar and weeds, their belowground interactions and particularly, the quantitative understanding of nutrient uptake using mechanistic models under weed-competing conditions. Therefore, the objectives of this study were to investigate the effects of dandelion and quackgrass on the growth of hybrid poplar, to establish their root uptake characteristics and to quantify their nutrient uptake using the soil supply and nutrient demand (SSAND) model. In a pot study, hybrid poplar stem height, root collar diameter, shoot and root biomass, root length, and N, P and K uptake significantly decreased in the presence of dandelion and quackgrass weeds. Similar weed competition effects on growth of hybrid poplar were also observed in the field at the Pasture and Alfalfa sites where hybrid poplar was grown with and without weeds for 50, 79 and 100 days. In a hydroponic experiment, Imax values for NH4-N, NO3-N, P and K varied significantly among hybrid poplar seedlings and dandelion and quackgrass weed species and was greatest for dandelion followed by hybrid poplar and then quackgrass. The Km values were lowest for quackgrass compared to the other plant species for all of the nutrients. Simulation results from the SSAND model for the pot study showed that N uptake was underpredicted in hybrid poplar by 58 to 73%, depending upon soil type and weed treatment. Incorporation of N mineralization as a model input improve the hybrid poplar N uptake predictions by 24 and 67% in the Pasture and Alfalfa soil, respectively, when grown without weeds. SSAND model underestimated P uptake by 84-89% and overestimated K uptake by 28 to 59% for hybrid poplar depending upon the soil type and weed treatment. In the field, N uptake by hybrid poplar was in close agreement to measured N uptake in the control treatment. N uptake was greatly underestimated for both hybrid poplar and weeds in the weed treatment. Including changing water content greatly improves the N uptake by hybrid poplar and weeds in weed treatments. Results from this study suggest weed control is an essential practice to establish successful hybrid poplar plantations. Also, SSAND model can be an effective tool for predicting the nutrient uptake under two plant species competing environment if all the processes of nutrient supply are adequately described in the model.
359

A study of the genetics and physiological basis of grain protein concentration in Durum wheat (<i>Triticum turgidum</i> L. var. <i>durum</i>)

Suprayogi, Yogi 11 December 2009 (has links)
In durum wheat (<i>Triticum turgidum</i> L. var <i>durum</i>), grain protein concentration (GPC) and gluten quality are among the important factors influencing pasta-making quality. Semolina with high protein content produces pasta with increased tolerance to overcooking and greater cooked firmness. However, genetic improvement of GPC is difficult largely because of its negative correlation with grain yield, and a strong genotype x environment interaction. Therefore, identification of quantitative trait loci (QTL) for high GPC and the associated markers is a priority to enhance selection efficiency in breeding durum wheat for elevated GPC. At a physiological level, GPC is influenced by several factors including nitrogen remobilization from vegetative organs and direct post-anthesis nitrogen uptake (NUP) from the soil. Understanding the relationship between elevated GPC and nitrogen remobilization, and post-anthesis NUP will enable durum wheat breeders to develop varieties that not only produce high yield and high GPC, but also exhibit better nitrogen use efficiency. The objectives of this study were: (1) to identify and validate QTL for elevated GPC in two durum wheat populations; and (2) to determine if elevated GPC is due to more efficient nitrogen remobilization and/or greater post-anthesis NUP. A genetic map was constructed with SSR and DArT® markers in a doubled haploid population from the cross Strongfield x DT695, and GPC data were collected in replicated trials in six Canadian environments from 2002 to 2005. Two stable QTL for high GPC, QGpc.usw-B3 on chromosome 2B and QGpc.usw-A3 on 7A, were identified. Strongfield, the high GPC parent, contributed the alleles for elevated GPC at both QTL. These two QTL were not associated with variation in grain weight (seed size) or grain yield. QGpc.usw-A3 was validated in a second Strongfield-derived population as that QTL was significant in all six testing environments. Averaged over five locations, selection for QGpc.usw-A3 resulted in a +0.4% to +1.0% increase in GPC, with only small effects on yield in most environments. A physiological study of grain protein accumulation revealed that regardless of the growing condition, nitrogen remobilization was the major contributor for grain nitrogen in durum genotypes evaluated, accounting for an average of 84.3% of total GPC. This study confirmed that introgression of Gpc-B1 into Langdon resulted in increased GPC, and this GPC increase was due to higher N remobilization. Strongfield expressed greater N remobilization than DT695 and the semi-dwarf cultivar Commander, but N remobilization was not the determining factor for Strongfields elevated GPC. Strongfield expressed greater post-anthesis NUP than DT695. Similarly, a selection of six high-GPC doubled haploid (DH) lines from the cross DT695 x Strongfield expressed significantly greater post-anthesis NUP than six low-GPC DH selections, supporting the hypothesis that elevated GPC in Strongfield is derived from greater post-anthesis NUP. All six high-GPC DH selections carried the Strongfield allele at QGpc.usw-A3, suggesting this QTL maybe associated with post-anthesis NUP.
360

Improvement Of Biohydrogen Production By Genetic Manipulations In Rhodobacter Sphaeroides O.u.001

Kars, Gokhan 01 October 2008 (has links) (PDF)
Rhodobacter sphaeroides O.U.001 is a purple non-sulphur bacterium producing hydrogen under photoheterotrophic, nitrogen limited conditions. Hydrogen is produced by Mo-nitrogenase but substantial amount of H2 is reoxidized by a membrane bound uptake hydrogenase. In this study, hydrogen production and the expression of structural nitrogenase genes were investigated by varying molybdenum and iron ion concentrations. These two elements are found in the structure of Mo-nitrogenase and they are important for functioning of the enzyme. The results showed that hydrogen production and nifD gene expression increased upon increase in molybdenum concentration. Increasing iron concentration had also positive effect on hydrogen production and nifK gene expression. To improve the hydrogen producing capacity of R. sphaeroides O.U.001, hupSL genes encoding uptake hydrogenase were disrupted in two different methods. In the first method, hup genes were disrupted by gentamicin resistance gene insertion. In the second method, part of the hup gene was deleted without using antibiotic resistance gene. The wild type and the hup- mutant cells showed similar growth patterns but substantially more hydrogen was produced by the mutant cells. The genes coding for hox1 hydrogenase of Thiocapsa roseopersicina was aimed to be expressed in R. sphaeroides O.U.001 to produce H2 under nitrogenase repressed and mixotrophic conditions. The hox1 hydrogenase genes of T. roseopersicina were cloned and transferred to R. sphaeroides. Although the cloning was successful, the expression of hydrogenase was not achieved by using either the native promoter of hox1 hydrogenase or the crtD promoter of T. roseopersicina.

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