Background: Despite the high success rates reported with the use of a five minute application of formocresol it has been postulated that it may be applied for a lesser amount of time and still achieve equivalent results. Few studies have adequately addressed the effects of the medicament on permanent successors and exfoliation times. Furthermore, the effects of shorter application times on success rates have not been adequately reported. Objectives: To assess the clinical and radiographic outcomes of a one minute application of full strength Buckley’s formocresol with concurrent hemostasis using the medicated cotton pledget in human primary teeth. To evaluate the effect of this technique on their successors and to evaluate the exfoliation times in comparison to the contralateral non-pulpotomized tooth. Methods: Using a retrospective chart review, clinical and radiographic data were available for 557 primary molars in 320 patients. Descriptive statistics and regression analysis were used to assess outcomes. Results: 99.3% clinical and 89.8% radiographic success rates were obtained. Internal root resorption (4.85%) and pulp canal obliteration (1.97%) were the most frequently observed radiographic failures. Sixty-five and half percent exfoliated at the same time as their contra-lateral counterpart and 28.8% exfoliated earlier (p<0.001). There was no difference in the number of enamel defects of succedaneous teeth between treated and control teeth (p>0.05). Conclusions: Success rates for the modified technique are comparable to techniques that use the five-minute dilute or full strength solutions reported in the literature. The one minute technique had no clinical effect on exfoliation times or incidence of enamel defects on succedaneous teeth. The one minute full strength formocresol technique is an acceptable alternative to published traditional techniques.

Background: Despite the high success rates reported with the use of a five minute application of formocresol it has been postulated that it may be applied for a lesser amount of time and still achieve equivalent results. Few studies have adequately addressed the effects of the medicament on permanent successors and exfoliation times. Furthermore, the effects of shorter application times on success rates have not been adequately reported. Objectives: To assess the clinical and radiographic outcomes of a one minute application of full strength Buckley’s formocresol with concurrent hemostasis using the medicated cotton pledget in human primary teeth. To evaluate the effect of this technique on their successors and to evaluate the exfoliation times in comparison to the contralateral non-pulpotomized tooth. Methods: Using a retrospective chart review, clinical and radiographic data were available for 557 primary molars in 320 patients. Descriptive statistics and regression analysis were used to assess outcomes. Results: 99.3% clinical and 89.8% radiographic success rates were obtained. Internal root resorption (4.85%) and pulp canal obliteration (1.97%) were the most frequently observed radiographic failures. Sixty-five and half percent exfoliated at the same time as their contra-lateral counterpart and 28.8% exfoliated earlier (p<0.001). There was no difference in the number of enamel defects of succedaneous teeth between treated and control teeth (p>0.05). Conclusions: Success rates for the modified technique are comparable to techniques that use the five-minute dilute or full strength solutions reported in the literature. The one minute technique had no clinical effect on exfoliation times or incidence of enamel defects on succedaneous teeth. The one minute full strength formocresol technique is an acceptable alternative to published traditional techniques.

The thesis aims at investigating an active power factor correction circuit. In boost power converter, we ser up average large signal model with Matlab and derive control¡Voutput function for pole assignment of control loop with ac small signal model. In controller, control circuit of conventional active power factor correction and modified PI control circuit are adopted, separately. Through simulation results and experimental responses of hardware circuit show that under variation of load or alternating input voltage, modified PI control circuit has better regulating capacity than that of conventional control circuit .

The purpose of this study was to identify school districts in the state of Texas that would be considered efficient based on the modified quadriform model, and to identify alterable school characteristics most associated with those efficient schools. The researcher used data from the 2003-2004 Texas Academic Excellence Indicator System in this analysis. Texas school districts that had low expenditures with high student output were classified as efficient. There were two stages to the modified quadriform analysis. In stage one the relationship between input and output was evaluated by two separate linear regressions. The input regression modeled total per pupil expenditure for the district regressed against unalterable school characteristics such as total district enrollment, percentage of economically disadvantaged students, percentage of special education students, percentage of minority students, and local tax base value per pupil. In the output regression six different measures of student outcomes were regressed against the same unalterable characteristics. The measures of student achievement used were the percentage of all students passing the math and reading Texas Assessments of Knowledge and Skills, graduation completion rate, percentage of students taking the Scholastic Aptitude Test and the ACT Test, and the mean scores on the Scholastic Aptitude Test and/or ACT Test. Once the efficient school districts were identified using the positive and negative residuals from the regressions, a discriminant analysis was conducted to determine what alterable characteristics had the most significant relationship with the different student outcome measures. Just over 32% of Texas School Districts would be considered efficient in this model, and the number of students per teacher has a significant relationship with the output measures of mean SAT and ACT scores, district completion rate, and Texas Assessment of Knowledge and Skills scores in both math and reading. The data also showed that the percentage of expenditures at central administration was least associated with mean Scholastic Aptitude Test and ACT scores along with district completion rate. This study was intended to be a descriptive “bird’s eye” view of efficiency in the Texas system, the researcher believes that this initial study will be a catalyst for more focused research using this production function method of measuring efficiency, and that one day it may lead to an operational definition of efficiency in the Texas system.

Thesis (B.A.) Summa Cum Laude --Butler University, 2009. / Includes bibliographical references (leaves 44-47).

The aim of this work was to develop and test a mathematical model for DNA transfer by conjugation which considered spatial separation of cells on surfaces. Model parameters include the initial donor and recipient numbers, maximum specific population growth rate, microcolony radial extension rate, maximum cell yield, maximum incubation time, standard deviation of the mean intercellular distance (σ), cellular area and area available for colonization. Sensitivity analysis indicated that growth areas and σ had the greatest effects on conjugation. The model was extended to consider the presence of a strain that did not conjugate and its effect on plasmid transfer. Filter matings with <I>Pseudomonas fluorescens</I> MON787 RP4 as the plasmid donor and <I>P. fluorescens</I> MON787 R <I>lux</I> as recipient were used to test the model. Model predictions were generally accurate but transconjugants were consistently underestimated. This was attributed to intercellular distances not following a strict Gaussian distribution. Nevertheless, predicted and experimental data were qualitatively similar, which increased confidence in the validity of the mechanisms proposed. Conjugation occurred over a wide range of cell densities, donor to recipient ratios, nutrient levels and incubation temperatures. Starved cells retained the capacity to conjugate, but plasmid transfer frequency was higher in the presence of nutrient. Above a minimum level, conjugation ability was not enhanced by nutrients. Temperature affected conjugation ability, the optimum being 20°C - 30°C. The presence of a nonconjugative strain decreased conjugation, by leading to earlier nutrient exhaustion and growth arrest which limited meetings between donor and recipient microcolonies. The model and the experimental system demonstrate the importance of spatial effects on conjugation. Description and prediction of gene transfer in natural environments will require models of greater complexity, and more sophisticated experimental testing, but this study provides a basis for theoretical descriptions of gene transfer in heterogeneous natural environments, such as soil and biofilms on solid surfaces in aquatic environments.

No description available.

The main tasks of this thesis were to evaluate a number of amperometric enzyme electrode chemistries for the selective and sensitive detection of L-lactate, and apply mass fabrication technologies to reproducibly manufacture sensors in a controllable manner. The sensors studied were based on the use of lactate oxidase with a range of modified-carbon electrodes. Noble metals, hexacyanoferrate (111) or Prussian Blue were used to modify carbon electrodes for the electro-catalytic determination of hydrogen peroxide, the product of the reaction of lactate oxidase with L-lactate. Tetrathiafulvalene was employed as an artificial mediator between the enzyme and the electrode. Polypyrrole was tested as a means of immobilising lactate oxidase and to achieve direct charge transfer to the underlying carbon electrode. The characteristics of the sensor responses to hydrogen peroxide, L-lactate and ascorbate were compared, in relation to the electrochemical electrode area. From this investigation, it was confirmed that screen-printed electrodes were more reproducible to manufacture than hand-fabricated electrodes. For screen-printed rhodinised-carbon electrodes, an operating potential of +400 mV (SCE) was selected. Interference from ascorbic acid and sensitivity to hydrogen peroxide were determined to be 26 μA.mM⁻¹.cm⁻² and 27 μA.mM⁻¹.cm⁻², respectively. Screen-printed carbon electrodes modified with platinum, rhodium or palladium were selected for further investigation. Rhodium on carbon performed the best in ten-ns of sensitivity and selectivity at low potentials, and different formations of rhodium-carbon complexes were studied. Although rhodium electroplated onto carbon screen-printed electrodes was examined, printing inks made from a preformed powder of rhodium on carbon-graphite proved to be the preferred route of electrode fabrication. Screen printing, ink-jet printing and Cavro solution deposition were employed to fabricate the amperometric enzyme electrodes. These sensors were composed of rhodinised carbon and lactate oxidase in a water-based electrode ink with a protective outer membrane layer. Each stage, from ink preparation to membrane composition, was developed empirically. The sensitivity, stability and reproducibility of the working electrode was improved by altering it to a homogeneous ink, consisting of carbon graphite powder, rhodinised carbon powder (5% Rh by weight), hydroxyethyl cellulose (2% w/v) and lactate oxidase in the weight ratio of 2:8:18:1. A layer of cellulose acetate (2% w/v in a 1:1 solution of acetone to cyclohexanone) and an outer coating of a polyurethane called Pellethane (1% to 4% w/v in dimethyl formamide and tetrahydrofuran) improved the selectivity, sensitivity and detection range of the sensor, allowing it to operate in physiological solutions with reduced passivation from protein adsorption. The sensor design was revised to allow its passage through a catheter and operation within a blood vessel; it was manufactured on flexible material using screen printing and Cavro solution deposition techniques. These miniature sensors, with a working surface of 0.5 x 15 mm, were capable of linearly measuring lactate up to 3 mM in buffer solutions with an average sensitivity of 44.8 nA.mM⁻¹ L-lactate. To test the sensor operation in physiological solutions, a flow injection system was employed. A planar three-electrode card used in this system was manufactured using screen printing and Cavro solution deposition techniques. L-lactate concentrations up to 6.4 mM were sensitively and, after minor correction, accurately determined in undiluted plasma and whole blood samples. This thesis has therefore made progress toward mass fabricating an amperometric enzyme electrode device suitable for the determination of L-lactate concentrations in vitro.

Most attempts to monitor the effects of introductions of Genetically Modified Micro-organisms (GMMs) have centred on the enumeration of specific populations. However for a significant perturbation to be measured, changes of between 100% and 300% (0.3 and 0.5 on a log scale) are necessary for the impact to be significant. Standard population measurements, assessing the survival, dissemination and effect on total indigenous populations do not give an indication of the functioning of the ecosystem. A range of soil enzyme assays have been developed as alternatives to population measurements. Assays for determining chitobiosidase, N-acetyl glucosaminidase, beta-glucosidase, beta-galactosidase, acid phosphatase, alkaline phosphatase, phosphodiesterase, aryl sulphatase and urease activities from small soil samples were developed. These assays were employed to assess the impact of microbial inoculation into the rhizosphere of crop plants and compared to traditional microbial population measurements. The impact of a chromosomally modified Pseudomonas fluorescens (SBW25) in the wheat rhizosphere using a large intact core microcosm was studied with a combined substrate addition of urea, colloidal chitin and glycerophosphate. The substrate addition caused an increase in the soil chitobiosidase, N-acetyl glucosaminidase aryl sulphatase and urease activities but did not affect acid and alkaline phosphatase and phosphodiesterase activity. Seed inoculated with P. fluorescens caused significant increases in rhizosphere chitobiosidase and urease activities and a significant decrease in alkaline phosphatase activity. Inoculation with the bacteria in the presence of substrate gave opposing effects to those treatments without substrate addition. Using these enzyme assays perturbations of less than 20% could be detected. Two strains of Pseudomonas fluorescens were compared in microcosm experiments one with a functional modification of strain F113 with repressed production of the antibiotic 2,4-diacetylphloroglucinol (DAPG), to create the DAPG negative strain F113 G22. The other, SBW25 EeZY 6KX, with nonfunctional modifications consisting of marker genes (LacZY, xylE and kan') only. Both were assessed, along with the corresponding wild types (F113 and SBW25), for their effects upon the indigenous microflora, plant growth and rhizosphere soil enzyme activities. Significant perturbations were found in the indigenous bacterial population structure, with the F113 (DAPG+) strain causing a shift towards slower growing colonies (K strategists). The DAPG+ strain also significantly reduced, in comparison with the other inocula, the total Pseudomonas populations. The survival of the F113 strains were an order of magnitude lower than the SBW25 strains. The DAPG+ strain caused a significant decrease in the shoot to root ratio in comparison to the control and other inoculants. The F113 (DAPG+) inocula resulted in higher alkaline phosphatase, phosphodiesterase and aryl sulphatase activities than the other inoculants and lower beta glucosidase, beta galactosidase and N-acetyl glucosaminidase activities. These results indicate that the soil enzymes are extremely sensitive to perturbations in the rhizosphere ecosystem and are sensitive enough to measure the impact of GMM inoculation.

No description available.