<p>The aim of this study was to determine how effective a chewing gum regime is in treating the common minor complaints of third molar surgery. The efficacy of a six-day chewing gum regimen in reducing pain, swelling and trismus after third molar surgery was compared to no chewing gum therapy. Third molar surgery is an important part of any maxillofacial surgery practice. There is an ongoing quest to find new and innovative methods to treat the minor complaints of this procedure.</p>

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Pesticide residue analysis is very important both in agriculture and environmental protection. The effectiveness of the analytical method depends very much on the extraction and preconcentration of the analytes prior to the actual analysis, as these analytes occur in trace concentrations that may be lower than the detection limit of the instrument. Various methods of extraction and pre-concentration have been introduced in an effort to decrease costs and other negative environmental impacts without compromising efficiency. One such method is single-drop micro-extraction (SDME), whose benefits cannot be overemphasised. This method has been recently introduced in the pool of pre-concentration methods for pesticide and other organic residues. In this study, the SDME method has been developed using chloroform as a solvent for preconcentration of a ten-component mixture of triazine (TP619) herbicides, followed by analysis by gas chromatography and flame ionisation detector (ppm level detection) and mass spectrometry for detection at sub-ppb level. The developed method uses the simple introduction of an air bubble to the micro-litre droplet of the organic solvent used for extraction of the triazines. This air-bubble showed the increase in the extraction efficiency of the method by about 30% relative to the optimised extraction without the air bubble. The air bubble works very well with addition of the salt (10% NaCl) to the solution being extracted, with further extraction enhancements being observed. Traditionally, the solution being extracted is stirred to achieve good mass transfer. However, the present method does not require stirring as stirring makes the system unstable resulting in reduced precision. The optimum conditions for the newly developed method, named bubble-in-drop single-drop micro-extraction (BID-SDME) were found to be as follows: 1 μL chloroform, 0.5 μL air bubble, 10% NaCl and static equilibration for 20 minutes, while the sample volume is 1 mL. This method showed linearity in the region of 1 ppm to 0.05 ppb (about six orders of magnitude) as long as the instrumental settings were optimised for increased sensitivity. The RSD values observed in this method were better than those recorded in literature, being <10%. Some instrumental manipulations are necessary to realise the full potential of the instrument. Various settings were explored on the GC-MS to optimise its performance below the ppb level. It was observed that the configuration that gave the best sensitivity and the lowest limits of detection was the high-pressure and split-less injection mode. This improved the detection limits of the instrument by 2 orders of magnitude (from 1 ppb to below 0.05 ppb). The GC-MS performance was further improved by the use of selected ion monitoring (SIM) mode of analysis. This technique reduced the interferences from the co-extracted compounds that can compromise the precision and accuracy of the analytical method especially at low concentration applicable in trace analysis. The new BID-SDME method was applied to various samples (dam water, synthetic hard water, dam sediment, humic and sandy soil samples) giving unsurpassed efficiencies with very low RSD values. In these systems, NaCl addition (10% w/v) not only increased extraction efficiency but also had a matrix-normalising effect as the RSD values were reduced and the matrix effects somewhat diminished. The application of this method to orange juice required the addition of only 5% NaCl (not 10% like the other samples). The results obtained with the extraction of orange juice were better than those recorded in literature. The normalising effect was further observed as the RSD values with addition of the NaCl were reduced the RSD from 11.7 (salt-free solution) to 5.56 (5% NaCl). These application experiments were carried out at the 0.2 ppb level using spiked samples. The method was compared against the other extraction techniques used in trace analysis (especially SPME) and it performed better overall giving lower RSD values and much improved detection limits. The calculated detection limits for the ten triazines used in the mixture were in the region of parts per trillion (0.9-14 ppt) with RSD values of < 10% with the use of internal standard. / Prof. D.B.G. Williams Mr. R. Meyer

Title: Ontology Enrichment Based on Unstructured Text Data Author: Ivana Lukšová Department: Department of Software Engineering Supervisor: Mgr. Martin Nečaský, Ph.D., Department of Software Engi- neering Abstract: Semantic annotation, attaching semantic information to text data, is a fundamental task in the knowledge extraction. Several ontology-based semantic annotation platforms have been proposed in recent years. However, the process of automated ontology engineering is still a challenging problem. In this paper, a new semi-automatic method for ontology enrichment based on unstructured text is presented to facilitate this process. NLP and ma- chined learning methods are employed to extract new ontological elements, such as concepts and relations, from text. Our method achieves F-measure up to 71% for concepts extraction and up to 68% for relations extraction. Keywords: ontology, machine learning, knowledge extraction 1

The aim of this thesis is to reconsider energy extraction from black hole magnetospheres, and more specifically the Blandford-Znajek (BZ) process from an effective field theory (EFT) perspective. Superradiant instabilities of scalar and vector bound states in the presence of a rotating black hole will be reviewed when the inverse mass of the black hole is much smaller than the Compton wavelength of the bound state particle. Two different matching calculations will be described for the vector bound state case and the overall decay rate will be compared. Force-free electrodynamics will be motivated and discussed in the context of the BZ process. Using a perturbation expansion, the Blandford-Znajek process will be reviewed up to second order in the rotation parameter. The absolute-space/universal-time (3+1) viewpoint will be discussed and applied to the BZ process and an EFT-like description will be discussed when the black hole horizon is parametrically small. Using differential forms, a simplified framework for the BZ process will be introduced in the (3+1) formalism and the field strength F will be simplified in the slow-rotation limit up to first-order in the rotation parameter. Finally, the Blandford-Znajek process will be considered as a superradiant process in the massive vector limit and the total energy flux in this (new) regime will be compared to the known BZ energy flux. / Graduate

The human effort in large-scale web data extraction significantly affects both the extraction flexibility and the economic cost. Our work aims to reduce the human effort required by web data extraction tasks in three specific scenarios. (I) Data demand is unclear, and the user has to guide the wrapper induction by annotations. To maximally save the human effort in the annotation process, wrappers should be robust, i.e., immune to the webpage's change, to avoid the wrapper re-generation which requires a re-annotation process. Existing approaches primarily aim at generating accurate wrappers but barely generate robust wrappers. We prove that the XPATH wrapper induction problem is NP-hard, and propose an approximate solution estimating a set of top-k robust wrappers in polynomial time. Our method also meets one additional requirement that the induction process should be noise resistant, i.e., tolerate slightly erroneous examples. (II) Data demand is clear, and the user's guide should be avoided, i.e., the wrapper generation should be fully-unsupervised. Existing unsupervised methods purely relying on the repeated patterns of HTML structures/visual information are far from being practical. Partially supervised methods, such as the state-of-the-art system DIADEM, can work well for tasks involving only a small number of domains. However, the human effort in the annotator preparation process becomes a heavier burden when the domain number increases. We propose a new approach, called RED (abbreviation for 'redundancy'), an automatic approach exploiting content redundancy between the result page and its corresponding detail pages. RED requires no annotation (thus requires no human effort) and its wrapper accuracy is significantly higher than that of previous unsupervised methods. (III) Data quality is unknown, and the user's related decisions are blind. Without knowing the error types and the error number of each type in the extracted data, the extraction effort could be wasted on useless websites, and even worse, the human effort could be wasted on unnecessary or wrongly-targeted data cleaning process. Despite the importance of error estimation, no methods have addressed it sufficiently. We focus on two types of common errors in web data, namely duplicates and violations of integrity constraints. We propose a series of error estimation approaches by adapting, extending, and synthesizing some recent innovations in diverse areas such as active learning, classifier calibration, F-measure estimation, and interactive training.

This work aims to develop solvent extractants to recover platinum and palladium from highly acidic chloride solutions bearing other platinum group metals (PGMs). In general, metal values can be recovered by solvent extraction through three different mechanisms: metal cation extraction (1); metalate anion extraction (2); or metal salt extraction (3). Mn- + n(LH)(org) ⇌ [M(L)n](org) + nH+ (1) MClx n- + nL(org) + nH+ ⇌ [MClx(LH)n](org) (2) MClx + nL(org) ⇌ [MClxLn](org) (3) The main objective of this thesis is to establish whether ditopic extractants can be developed which have chemical functionalities that allow both mechanisms (2) and (3) to operate, co-extracting Pt(IV) and Pd(II) as their chloridometalates in an outer sphere binding site (2) and allowing their separation by raising pH to transfer the more kinetically labile Pd(II) to an inner sphere binding site (3) and releasing H2PtCl6 to the aqueous strip solution. A review of the literature is presented in Chapter 1, noting current commercially available extractants and the processes in which they are, or have been, applied. Particular attention is paid to the mode of action of the reported extractants and whether they extract metal cations, anions or metal salts. This chapter also outlines the proposed solvent extraction circuit in which new reagents developed in this thesis would be incorporated and the methods applied during the screening of candidate extractants. Chapter 2 deals exclusively with the use of reagents with inner-sphere binding sites for the selective extraction of palladium over platinum. Work on a series of oxime reagents synthesised for palladium extraction as part of preliminary MSci research (Andrew M. Wilson, MSci Thesis, University of Edinburgh, 2011) is reviewed. Studies of the hydrolytic stability of oximes indicate that they are unsuitable for incorporation into ditopic reagents for use in a circuit with a highly acidic feed solution. Thioethers were studied as alternatives as they show high kinetic selectivity for palladium over platinum and are more stable under acidic conditions. The synthesis and extraction properties of model reagents (largely arylalkyl thioethers) are reported and compared with those of the commercially available di-n-hexylsulfide. Incorporation of a polar group such as an amide provides phase transfer catalysis, accelerating the rate of transport of Pd(II) into the organic phase, but reducing selectivity over Pt(IV). The identification of functionalities that operate as receptors for chloridometalates by forming outer-sphere assemblies is explored in Chapter 3. The synthesis of amine, amide and amino-amide extractants from acid chloride streams and the effects of variations of functional groups on the extraction of PtCl6 2− are described. Secondary amides were found to be stronger extractants than tertiary amides, and aliphatic amides also show better metalate extraction than aromatic amides. The interactions between protonated aminoamide reagents and PtCl6 2− werre analysed by X-ray crystallography, noting that C-H∙∙∙Cl interactions with the “soft” chloridometalate anion are more common than with the “hard” chloride ion which shows a preference for more conventional N-H∙∙∙Cl interactions. Chapter 4 combines the reagent types explored in Chapters 2 and 3, in ditopic extractants that have both inner- and outer sphere binding sites. The synthesis and characterisation of a series of thioether amide reagents are reported and the selective extraction of platinum and palladium over other PGMs are discussed. In-house screenings of aryl- and alkylthioetheramide extractants showed selective co-extraction of Pd(II) and Pt(IV), rejecting Ir(III). Pt(IV) can be selectively water-stripped followed by ammonia-stripping of Pd(II). Industrial screenings at Johnson Matthey Technology Centre further exemplified the selectivity of these extractants over Ru(III) and Rh(III), although third phases were formed when the reagents were used for recovery from highly concentrated metal-feed solutions. The mode of action of the ditopic extractants is discussed, based on DFT calculations, crystal structure determinations and NMR studies, which support the formation of outersphere metalate assemblies and inner-sphere palladium complexes. Chapter 5 describes new difunctional (inner + outer sphere complexation) extraction by a single chemical entity, in this case an unsaturated N-heterocycle (an azole). The synthesis and characterisation of a series of hydrophobic azoles are described. These have basicities which allow protonation when contacted with strongly acidic solutions (2), but can be deprotonated in contact with water to allow their neutral forms to form inner-sphere complexes with Pd(II). Triazole-based reagents show the selective co-extraction of Pt(IV) and Pd(II) and, as with the ditopic thioetheramide reagents reported in Chapter 4, allow the selective water stripping of Pt(IV) and subsequent ammonia stripping of Pd(II).

Thesis (M.S.)--Virginia Polytechnic Institute, 1954. / Typewritten. Vita. Bibliography: leaves 191-199. Also available via the Internet.

The goal of this research is to improve an extractive metallurgy process based on solvent extraction. This process should fit the exploitation of small local copper-rich deposits. In these conditions, the plant has to be as compact as possible in order to be easily transported from one location to a subsequent one. Improved extraction kinetics could ensure a high throughput of the plant despite its compactness. In addition, the extraction reagent should not be damaging for the environnement. On this basis, we propose to use ultrasound-assisted solvent extraction. The main idea is to increase the extraction kinetics by forming an emulsion in place of a dispersion thanks to the intense cavitation produced by ultrasound. The benefit of this method is to improve the copper extraction kinetics by increasing the interfacial surface area and decreasing the width of the diffusion layer. We studied the implementation of an highly branched decanoic acid (known as Versatic- 10®acid) as a copper extraction reagent dispersed in kerosene. Emulsification is monitored through the Sauter diameter of the organic phase droplets in aqueous phase. This diameter is measured during pulsed and continuous ultrasound irradiation via a static light scattering technique. The phenomenon of emulsification of our system by ultrasound is effective, and the emulsification process carried out in the pulsed ultrasound mode is at least as efficient as the emulsification obtained under continuous mode. No improvement of emulsification is observed beyond a threshold time of the ultrasound impulse. This may be attributed to a competition between disruption and coalescence. The use of mechanical stirring combined with pulsed ultrasound allows to control the droplet size distribution. In presence of ultrasound, the extraction kinetics of Versatic-10 acid is multiplied by a factor ten, and therefore reached a value similar to the kinetics observed without ultrasound with an industrial extractant such as LIX-860I®(Cognis). Extraction kinetics measurements are carried out by monitoring the copper ion concentration in the aqueous phase with an electrochemical cell. We conclude that ultrasound-assisted emulsification can be implemented under certain conditions. Emulsification is a first step, and the following destabilization step has to be studied. The device using ultrasound-assisted emulsification should be followed by an efficient settling-coalescing device. A possible solution would be to promote emulsion destabilization by increasing the ionic strength with an addition of MgSO4, a salt that is not extracted by the extraction reagent in the considered range of pH.

This thesis summarizes an investigation into the need for removing extractives from herbaceous biomass feedstocks prior to their chemical characterization. Switchgrass (Panicum virgatum), was used in this study as a representative herbaceous biomass feedstock. The influence of extractives on the chemical analysis of switchgrass was done by comparing the composition of native switchgrass and solvent-extracted switchgrass preparations. Solvent-extracted switchgrass was prepared by extracting the native feedstock with either 95% ethanol, hot water or sequentially with ethanol and then water. Each of the feedstocks was analyzed for glycans, Klason lignin, acid soluble lignin, protein, ash, acetic acid and uronic acids. The results demonstrate that the extractives in native switchgrass significantly interfere with the analysis of Klason lignin. The lignin content of the feedstock was overestimated if the extractives were not removed prior to the analysis. The extractives in switchgrass did not affect glycan analyses. However, some soluble sugars are removed from the feedstock during the solvent extraction process. Total extractives removed by ethanol, water and ethanol/water amounted to 9.74%, 16.42%, and 19.11% of the feedstocks total solids, respectively. These amounts of extractives increased Klason lignin values by 4%, 4.5%, and 6.5% (on a wt percent of total solids), respectively. Most of the extractives in switchgrass are water-soluble and approximately one-quarter of these extractives measure as Klason Lignin. The removal of the water soluble extractives from the feedstock improved the mass closure values for the feedstock's summative analysis. Successive ethanol and hot water extraction has successfully removed most of the extractives in switchgrass yielding 100.4% mass balance. The recommended approach for the analysis of herbaceous biomass feedstocks will include sequential 95% ethanol and hot water extraction followed by chemical analysis on both the preextracted substrate and the extractives obtained from that substrate. / Graduation date: 1996