Parallel Processing For Schema Evolution in Database Systems

A thesis submitted to the University of London in partial fulfillment of the requirements of the degree of Doctor of Philosoph

Selective versus stepwise removal of deep carious lesions in permanent teeth: a randomised controlled trial from Egypt-an interim analysis

OBJECTIVES: To compare the success, survival and costs of selective versus stepwise carious tissue removal (SE/SW) in permanent teeth with deep (>2/3 dentine depth) carious lesions. DESIGN: Randomised controlled, unicentre, clustered two-arm superiority trial. SETTING: Outpatient clinic of a private university in Cairo, Egypt. PARTICIPANTS: One hundred and fifteen participants (n=132 teeth), aged 18-47 years, from Cairo, Egypt, were enrolled. Premolars/molars with occlusal/occlusal-proximal deep lesions (radiographically >2/3 dentine), sensible pulps, without spontaneous pain, were included. INTERVENTIONS: Peripheral carious tissue removal to hard dentine was performed. Pulpo-proximally, soft dentine was left. A glass ionomer (GI) restoration was placed. After 3-4 months, teeth were randomly allocated to SE (n=66), with reduction of the GI into a base and no further tissue removal, followed by a composite resin restoration, or SW (n=66), with full removal of the GI, additional excavation until firm dentine pulpo-proximally, followed by a GI-based composite restoration. Mean follow-up was 1 year. PRIMARY AND SECONDARY OUTCOME MEASURES: Primary outcome was success (absence of endodontic/restorative complications). Secondary outcomes were tooth survival and initial and total treatment costs. RESULTS: Zero/five pulp exposures occurred during SE/SW, and seven/five SE/SW teeth required endodontic therapy. Success after 12 months was 89.4% for SE and 84.9% for SW. The estimated mean time free of complications was 23 and 18 months for SE and SW, respectively, without significant differences between SE and SW (p>0.05/Cox). Initial treatment costs were significantly higher for SW (mean (SD): 507.5 (123.4) Egyptian pounds (EGP)) than SE (mean (SD): 456.6 (98.3) EGP), while total costs showed no significant difference (p>0.05). CONCLUSION: Within the limitations of this interim analysis, and considering the depth of these lesions (>2/3 dentine), SE and SW showed similar risk of failure and overall costs after 1 year

Structural, Magnetic And Electrical Studies On Some Mixed Metal Perovskite Oxides

This thesis describes crystallographic, magnetic and electrical studies of some mixed metal perovskites. In the first part, the charge distribution, magnetic and electrical properties of mixed metal rhodium-copper perovskite oxides were investigated. Various series with the general formula Ln1-yAyRh1-2xCuxBxO3 in which (Ln = La3+, Tb3+; A = Ca2+, Sr2+, Pb2+, Bi3+; B = Sc3+, Cu2+, Zn2+ ; y ≤ 0.3, x ≤ 0.25), have been synthesised by solid state reaction, and characterised by X-ray diffraction, scanning electron microscopy and physical property measurements and, as available, neutron diffraction and X-ray absorption near edge structure measurements. Structures were invariably orthorhombic with space group Pbnm with the Rh and Cu ions disordered on the same site. X-ray diffraction measurements of selected samples showed that the orthorhombic structure persisted over a wide temperature range, 30 to 900 ºC. All the samples are semiconductors and paramagnetic over the temperature range 4-300 K. Doping a divalent cation onto the B site appears to have a significant impact on charge delocalization between Rh3+/4+ and Cu2+/3+ ions due to the oxidation of Rh3+ to Rh4+ required to maintain the overall charge. That was most evident from the Rh L3 XANES measurements of the LaRh1-2xCu2xO3 and La1-xPbxRh0.5Cu0.5O3 series. Powder neutron diffraction measurements of La0.75Pb0.25Rh0.5Cu0.25Zn0.25O3, LaRh0.5Cu0.25Zn0.25O3 and La0.75Pb0.25Rh0.5Cu0.5O3 show no evidence for anion vacancies and it is postulated the oxides do not contain appreciable amount of oxygen vacancies. The magnetization curves show negative values for Weiss constants indicating weak antiferromagnetism may be present but there is no indication for long range coupling in the oxides. There are several factors that may influence the magnitude of the cell volume, octahedral distortion, octahedral tilting, magnetic interactions and electronic properties. These include ionic size, effective charge, electron configuration and electronegativity. In addition the charge delocalization and local ordering effects can play a role. The present work has demonstrated that: The changes in the unit cell volume and the octahedral distortion of the isovalent doped oxides such as La0.75A0.25Rh0.7Cu0.3O3 where A = Ca2+, Sr2+ and Pb2+ are consistent with the increase in the ionic radii, whereas the decrease in magnetic moments of these is correlated with the increase in the electronegativities of the dopant cation. The unit cell volumes for the terbium oxides are somewhat smaller than found in the analogous lanthanum oxides reflecting the small ionic size of Tb3+. The divalent cation doped oxides LnRh1-2xCu2xO3 and LnRh1-2xCuxZnxO3 display lower cell volumes and octahedral distortions but higher magnetic moments and electrical conductivities than the trivalent cation doped oxides LnRh1-2xCuxScxO3 as consequence of charge delocalization. The electrical conductivity of the oxides increases as the divalent dopant content increases possibly because of an increase in carrier concentration that occurs as consequences of the formation of ionic defects due to the oxidation of Rh3+ (3d6) to Rh4+ (3d5). The electron configuration influences the spin coupling and the band gap and this is most evident in the Pb2+ and Bi3+ (6s2) doped LaRh1-2xCu2xO3 oxides which exhibited the lowest magnetic moments and the highest activation energies among the oxides studied. Compared with the analogous lanthanum oxides, the magnetic susceptibilities of the terbium oxides increased as a consequence of the contribution of Tb3+ 4 f8 electrons. Changing the A site composition resulted in anomalous changes in the cell volumes, octahedral distortions, electrical resistivity and magnetic susceptibility of the La1-xPbxRh0.5Cu0.5O3 and La1-xBixRh0.5Cu0.5O3 perovskites. This is likely a consequence of charge delocalization and short-range local ordering effects. Increasing the doping on the B-site resulted in either a decrease or increase in the cell volumes and the magnetic moments, depending on the dopant type cation. The final part of this thesis describes the structure of some Ba2-xSr1+xBO5.5 (B = Nb5+ and Ta5+) perovskites. These were characterised by scanning electron microscopy, thermogravimetric analysis, X-ray and neutron diffraction. The preparation of these used solid state methods but the initial reactions were conducted under different media. Four compounds were prepared and these all have a face centred cubic structure with space group Fm3 ̅m. The two synthetic methods produce monophasic powders and these differ in color, particle size, and hardness. The cell edges of the oxides obtained by mixing the reactants with water are larger than these obtained when the mixing was conducted with acetone. The neutron diffraction profiles demonstrate that the A cation and oxygen ions are disordered in the BaSr2NbO5.5 and BaSr2TaO5.5 structures. The unusual thermal expansion of the unit cell is due to the presences of water and anion deficiency into the oxides structure. The oxides were found to absorb CO2 atmosphere during storage

FORMULATION AND EVALUATION OF ATORVASTATIN CALCIUM NANOCRYSTALS CONTAINING P-GLYCOPROTEIN INHIBITORS FOR ENHANCING ORAL DELIVERY

Objective: The main objective of this study was to develop atorvastatin calcium (ATR) as an oral drug delivery system for a P-glycoprotein (P-gp) substrate drug using different pharmaceutical excipients that inhibit P-glycoprotein and evaluate the influence of nanocrystals on the dissolution characteristics and bioavailability compared to the plain drug. Methods: A nanosuspension was prepared by Solvent-antisolvent precipitation method using a solvent containing stabilizer that act as a p-gp inhibitor dissolved in distilled water as polyethylene glycol 300, polyethylene glycol 400 (PEG 300, PEG 400), tween 20 and tween 80 while the solvent selected for atorvastatin calcium was methanol. The concentrations were as follows: PEG 300 and 400 = 0.25% w/v, tween 20 and 80 = 0.75% v/v. Nanocrystals were extracted from the suspension and characterized. Results: Particle size of the drug was 1307±127.79 nm while the formulas prepared ranged from 223±17.67 to 887±58.12 nm. Pure ATR had a saturated solubility of 0.059±0.005 mg/ml and the prepared nanocrystals ranged from 0.32±0.021 to 0.88±0.019 mg/ml. The Percentage of drug released of plain atorvastatin calcium reached 41.49% while the formula ranged from 44.32 to 61.5%. Both XRD and SEM discussed the degree of crystallinity as follows: F1<F2<F4<F3<ATR. Conclusion: 0.3% of PEG 300 and PEG 400 were not enough to formulate proper nanocrystals while 0.75% tween 20 and tween 80 achieved acceptable formulas. F4 which is prepared with tween 80 exhibited the highest enhancement in saturated solubility, dissolution rate and subsequently expected to have improved oral bioavailability

Effect of planting methods of flax on garlic yield under different intercropping patterns

The purpose of this experiment was to investigate yield, yield components and economic evaluation of flax (Sakha 5) and garlic (Sids 40) under various planting methods and intercropping patterns. The experimental design was a split-plot design with four replicates. The main-plots were assigned to the three cultivating methods and the sub-plots were allocated to the four intercropping patterns. The results indicated that drilling as planting method achieved the highest values for most studied characters in both seasons for flax and garlic, except for number of cloves/plant and plant height in garlic. Intercropping system with low garlic density (100% flax + 12.5% garlic) produced the maximum values for stem diameter, straw yield, number of capsules and seed/plant, seed index and seed yield for flax and number of leaves and cloves/plant, head diameter and weight for garlic in both seasons. The highest bulb yield of garlic was achieved with intercropping 100% flax + 37.5% garlic in both seasons. It can be concluded that the most economic returns for both crops were obtained from drilling as planting method with intercropping pattern 100% flax + 37.5% garlic under the environmental conditions of North Delta of Egypt. Keywords: Intercropping, Land equivalent ratio (LER), Aggressivity (Ag), Relative crowding coefficient (RCC), economic evaluatio

Data Collection Protocols For Wireless Sensor Networks

Data collection in wireless sensor networks (WSNs) has a significant impact on the network’s performance and lifetime. Recently, several data collection techniques that use mobile elements (MEs) have been recommended, especially techniques that focus on maximising data delivery. However, energy consumption and the time required for data collection are significant for many WSN applications, particularly real-time systems. In this paper, a review of data collection techniques is presented, providing a comparison between the maximum amount shortest path (MASP) and zone-based energy-aware (ZEAL) data collection protocols implemented in the NS-3 simulator. Finally, the study provides a suitable data collection strategy that satisfies the requirements of WSN applications in terms of data delivery, energy consumption, and the time required for data collection

Atropa Belladonna intoxication: a case report

Atropa Belladonna is a poisonous plant also called deadly nightshade. Its roots, leaves and fruits contain alkaloids: atropine, hyocyamine and scopolamine. The risk of poisoning in children is important because of possible confusion with other berries. Atropa Belladonna acute intoxication is a severe condition, it's should be considered in the presence of anti-cholinergic toxidrome, the differential diagnosis include other plants or psychoactive drugs containing atropine. The treatment is mainly symptomatic including gastrointestinal decontamination with activated charcoal. In severe cases, physostigmine can be used as an antidote. We report the case of 11 year old girl with Atropa Belladonna poisoning which was administrated in a therapeutic purpose as a remedy to jaundice. The child presented essentially a central anti-cholinergic syndrome. She was admitted in the intensive care unit, the progression was favorable with symptomatic treatment

Crossflow absorber characterisation for the direct air capture of carbon

Carbon capture and storage (CCS) and direct air capture (DAC) are necessary technologies in the achievement of global climate targets. Innovative ways to enhance CCS and DAC (by making them cheaper, reducing the land area required, smaller energy requirements, etc.) are being studied to facilitate accelerated large-scale, deployment of CCS and DAC globally. One promising innovation for implementing CCS and/or DAC is using crossflow absorbers. Crossflow absorbers can operate at a wider range of fluid flowrates than counterflow absorbers, therefore, larger volumes of gas can be processed faster. Crossflow absorbers also have pressure drops that are much lower than those of counterflow absorbers, meaning their operating costs are lower. Additionally, crossflow absorbers can be built in a modular fashion (i.e., they are flexible and do not need to be tall, vertical columns) that allows them to be adapted to the needs of each specific location with minimal visual impacts. However, liquid entrainment and liquid carryover are significant drawbacks of crossflow absorbers. Both these phenomena can reduce mass transfer efficiency, as well as result in the need for more rigorous downstream processes to condense and collect the solvent from the gas phase to prevent solvent loss to the atmosphere. Previous studies have shown that liquid entrainment and liquid carryover may be countered by changes to the packing geometry (Lavalle et al., 2018). The packing that is available for use in crossflow gas-liquid contactors is designed for cooling tower applications and is optimised for the heat transfer processes that take place in cooling towers, rather than the mass transfer processes that are needed for CCS (Holmes and Keith, 2012). A pilot-scale test rig was developed and used to experimentally investigate the hydrodynamic and mass transfer performance of crossflow absorbers. The experimental test campaign used an air and sodium hydroxide system and the obtained data was analysed using response surface methodology (RSM). The crossflow absorber was found to have pressure drops 16% to 50% smaller than those in counterflow absorbers, and liquid holdups -50% to 200% different from those in counterflow, with the difference in liquid holdups increasing with decreasing liquid loads irrespective of packing set. Lower pressure drops can result in a lower energy requirement. The mass transfer performance of the crossflow absorber was found to be at most 15% smaller than that of counterflow absorbers. Sulzer’s Mellapak 250Y.PP structured packing was investigated to determine its performance in crossflow absorbers, along with five other packing sets produced by tilting the Mellapak 250Y.PP at different angles to investigate the effect of tilting the packing on its performance and determine whether the packing can be optimised for use in crossflow absorbers. Out of the structured packing sets that were tested, the set tilted at 82° was found to be the one with the best performance. The crossflow absorber’s operating conditions were optimised to maximise effective interfacial mass transfer area and minimise pressure drop. The optimum operating conditions were found to be 5.06 m/sec gas flowrate and 1.17 L/m2·sec liquid flowrate, which is equivalent to an L/G ratio of 0.3, for Sulzer Mellapak 250Y.PP packing that has been tilted 90±8°. Finally, empirical equations for pressure drop, liquid holdup, and effective interfacial mass transfer area were developed from the experimental data collected from the crossflow absorber test rig. These empirical equations were incorporated in a preliminary rate-based model that had been developed by previous members of the CCS research group. These empirical equations reduced the model’s average absolute relative deviation (AARD) from 216% to 3.3% for pressure drop, from 512,854% to 9,305% for liquid holdup, and from 43% to 30% for effective interfacial mass transfer area