The research presented herein is concerned with the exploration of the rhodium catalysed addition of organoboron reagents. Chapter 1 firstly introduces the area of organoboron reagents, focussing on the applications of potassium alkenyl trifluoroborate reagents. Secondly, an extensive discussion of the rhodium catalysed conjugate addition of organboron reagents demonstrates its utility as a key coupling step in recent syntheses. Chapter 2 describes synthetic methods towards alkenylboron reagents and describes the synthesis of functionalised and enantiopure alkenyl trifluoroborate salts. Chapter 3 discusses the rhodium catalysed addition of potassium alkenyl trifluoroborate salts to α,β-unsaturated compounds. A gas chromatography study addresses issues concerning protodeboronation and highlights the potential for olefin transposition. A new rhodium catalysed olefin transposition reaction has been thoroughly investigated and applied using the synthesised potassium alkenyl trifluoroborate salts. Chapter 4 describes the synthesis of biologically relevant, enantiopure dihydropyranones for use as acceptors in the rhodium catalysed conjugate addition reaction. The hetero-Diels-Alder reaction is employed to synthesise the dihydropyranones. Rhodium catalysed conjugate addition of arylboronic acids and potassium alkenyl trifluoroborates is utilised to concisely assemble late stage intermediates of natural products including diospongin B. Chapter 5 describes the synthesis and characterisation of the compounds discussed in chapters 2, 3 and 4.

The decomposition behavior of several mining reagents (i.e., xanthate, dithiocarbamate, dithiophosphate and dithiophosphinate) used widely in mineral processing operations was studied. Decomposition has been reported to generate toxic compounds such as CS₂ (carbon disulfide) and COS (carbonyl sulfide), causing severe concerns to SHE (safety, health and environment). With the global trend of becoming sustainable/green and the increasingly strict regulations, the mining industry is facing an unprecedented pressure to handle the problematic reagents that can lead to the adverse impacts. Unfortunately, the interests of the prior research are biased on the performance of the reagents to optimize the efficiency and lower the cost, while the examination of the decomposition behavior is almost neglected. Under the circumstance of poor endeavor found in the prior investigations, the knowledge gap awaits to be filled in a systematic and integrated manner to recommend countermeasures for those problematic reagents. It can be seen from those fragmented studies collected from literature that only a limited understanding of thermal or aqueous decomposition behavior is achieved. It is far from sufficient for industrial guidance of mitigation. One key reason is the lack of robust methods to investigate decomposition under various conditions that are interesting to the mining companies (e.g., the flotation conditions). Consequently, the method development has always been considered of the utmost importance upon the start of this work to align with our overall goal of understanding the decomposition behavior under the various conditions. Three methods under a consistent strategy were designed to examine the decomposition under three conditions from Simple (in aqueous solutions alone), to Complex (in ore pulp under flotation conditions), to Specific (in solution containing metal ions). These three conditions were chosen based on the general interests from several prominent mining companies (Vale, Barrick, Freeport McMoRan and Newmont) to understand the decomposition mechanism and kinetics. The Simple is to serve as control for all other conditions. Besides, most of the prior studies in the literature are only conducted for the Simple condition. Therefore, the Simple is to resolve all discrepancies and conflicts, and provide a relatively comprehensive summary of the decomposition under the control condition. The Complex puts decomposition in a new environment that has never been explored before: the ore pulp under the simulated batch flotation conditions. Conclusions drawn from this part provide the most practical guidance for industrial mitigation. The Specific goes after the Complex to thoroughly understand the effect of a specific factor on decomposition. The decomposition responding to the variation of a certain factor is followed within a closed system with the compositional changes measured in all phases. The integrated analysis enables the correlation of the decomposition behavior to its original causes, which are the interactions of the reagent with other components in the system. Through the systematic investigation of decomposition of various reagents under various conditions, it is concluded that decomposition depends heavily on those parallel or sequential interactions that occur along with the decomposition reaction. For example, the decomposition reaction of xanthate throughout our entire study is regarded as ROCS₂⁻→CS₂. When xanthate forms xanthic acid, monothiocarbanate or dixanthogen with the change of pH, its breakup into CS₂ is altered. When xanthate interacts with Cu²⁺ forming Cu₂X₂, decomposition is depressed, but with Fe³⁺ forming FeX₃ decomposition is promoted. The CS₂ generated from decomposition could interact with OH- to form CS₃²⁻ or dissolve in solution or adsorb on minerals, leading to the decrease of CS₂ detected. The bonding properties between the –CS₂ moiety and other atoms or radicals in the molecule affect the stability of the reagents and the subsequent decomposition. The necessity to include a list of the side-interactions as complete as possible is key to understand and predict the decomposition behavior. With experimental efforts taken to develop methodologies to measure the decomposition under various conditions, the attempt to model the decomposition behavior is also initiated in this work. Based on the conclusions from experimental results, major components determining the output of the final decomposition products are identified. Unsurprisingly, the decomposition reaction together with its parallel and sequential interactions is critical. Simulation using Matlab to assess the decomposition of a simplified system containing SIBX and Cu²⁺ ions has achieved preliminary success by matching well with the experimental measurements. This establishes the groundwork for furthering the simulation of more complex systems and model development. Reagents decompose differently, although they might be applied to function similarly during an operation. As flotation collectors used for sulfide ore beneficiation, dithiocarbamate and xanthate possess some similarities in the decomposition in terms of generating CS₂. Their decomposition also decreases with the chain length. On the other hand, the decomposition of dithiophosphate and dithiophosphinate are different as the breakup of the molecule is mainly at their alkyl chain to generate moieties such as olefins. Compared to the studies carried out to understand the performance of the reagents when being used, research on decomposition requires more attention. Therefore, derivative work can be conducted based on results achieved in this work. For example, it is useful to further examine how reagents decompose after adsorbing on the mineral surfaces. It complements the knowledge to thoroughly understand decomposition at different spots within a complex system. The chemical fate studies of mining reagents with respect to the understanding the decomposition open up the window of developing methodologies to examine adverse behaviors. The experimental setups are applicable to simulate various conditions under which the reagent is being used and generating the adverse impacts. The strategy of analyzing decomposition within a complex system as shown in this study also provides insight into systematically investigating the other types of adverse behaviors.

Cloreto estanoso (SnCl2.2H2O) é o composto mais utilizado na redução do íon pertecnetato (TcO4-), obtido pela eluição do gerador, para a marcação de reagentes liofilizados para radiodiagnóstico. Estes reagentes liofilizados contêm um ligante, cloreto estanoso, e diferentes excipientes. Muitos métodos analíticos para a determinação de estanho não conseguem distinguir entre os íons estanoso (Sn(II)) e estânico (Sn(IV)) em soluções. Os dois métodos, descritos na literatura, para determinação seletiva de Sn(II) são análise titrimétrica e polarografia. O método mais confiável descrito para a quantificação do íon estanoso é a polarografia (voltametria) e pode ser utilizado para a determinação em concentrações de mg e g de Sn(II) e Sn(IV) (0,06-1,0 mg), com boa seletividade. Foi realizada análise titrimétrica, para quantificação de Sn(II), na matéria-prima e em 3 lotes consecutivos de 9 reagentes liofilizados produzidos pelo IPEN-CNEN/SP, utilizando-se sulfato cérico 0,1 mol L-1, diluído 10 vezes e iodo 0,05 mol L-1, diluído 10 vezes, como soluções titulantes. Polarografia por pulso diferencial foi utilizada com configuração convencional composta por três eletrodos: eletrodo de trabalho de gota de mercúrio, eletrodo referência de Ag/AgCl (saturado com KCl) e eletrodo auxiliar de platina. O intervalo de potencial analisado foi de -250 a -800 mV e o pico atribuído à redução de Sn(II) foi encontrado em -370 mV em eletrólito suporte de H2SO4 3 mol L-1 e, para Sn(IV), -470 mV, em eletrólito suporte de HCl 3 mol L-1. Para retirada do oxigênio da solução na cela polarográfica utilizou-se nitrogênio 5.0 por 5 minutos, antes e após cada introdução de amostra. Para determinação de Sn(IV) foi feita a oxidação do Sn(II), por adição de peróxido de hidrogênio, em 37 ± 5 ºC, por 5 minutos, seguida de purga com nitrogênio, e análise. A análise polarográfica desenvolvida mostrou-se adequada para a determinação de Sn(II), na presença de Sn(IV), e de estanho total nos kits radiofarmacêuticos estudados. / Stannous chloride (SnCl2.2H2O) is the major compound used for reduction of generator-derived 99mTc-pertechnetate in cold kits for on site preparation of 99mTc-radiopharmaceuticals. These cold kits usually contain a ligand, stannous chloride, and different additives. Various techniques were described for tin determination, but they cannot distinguish between stannous (Sn(II)) and stannic (Sn(IV)) ions in solutions. The two methods described in literature for selective determination of Sn(II) are polarography and mass analysis (redox-titration). Polarography is a good selective method in the mg range as well as in the g range for Sn(II) and Sn(IV) (0.06-1,0mg). Titrimetric analysis was performed for quantification of Sn(II) in Sn(II) reagents and in 3 consecutive lots of 9 radiopharmaceutical cold kits produced by IPEN-CNEN/SP, using Ce(SO4)2.4H2O 0.1 mol L-1, diluted 10 times and, I2 0.05 mol L-1, diluted 10, as a titrant solution. Differential pulse polarography was chosen with a conventional three-electrode configuration consisting of a static mercury drop electrode, an AgCl/Ag (saturated KCl) reference electrode and a platinum wire auxiliary electrode. The potential was swept from 250 to 800 mV and the current (A) was measured at 370 mV and 470 mV potentials for Sn(II) in H2SO4 3 mol L-1 and Sn(IV) in HCl 3 mol L-1, respectively. The supporting electrolytes were deaerated during 5 min with 5.0 nitrogen gas before and after each sample addition. For total tin determination the oxidation of tin (II) was carried out in the same vial, by adding H2O2 at 37 ± 5 ºC, for 5 min to quantify tin (IV). The developed polarographic method showed to be adequate to quantify tin (II), in the presence of tin (IV), in analyzed radiopharmaceutical cold kits.

Submitted by Rosivalda Pereira (mrs.pereira@ufma.br) on 2017-06-12T18:19:02Z No. of bitstreams: 1 BismarckAscarSauaia.pdf: 1915965 bytes, checksum: 720a005798d94ec0d82a2ba0cf2b225e (MD5) / Made available in DSpace on 2017-06-12T18:19:02Z (GMT). No. of bitstreams: 1 BismarckAscarSauaia.pdf: 1915965 bytes, checksum: 720a005798d94ec0d82a2ba0cf2b225e (MD5) Previous issue date: 2016-03-31 / Estimation of blood glucose levels using invasive methods currently is a routine in emergency and ambulatory attendance of public health services, as well as in residential glucose monitoring, in order to prevent glucose levels variation, which may evolve to ophthalmic, renal, vascular and neurological complications. In order to develop a low-cost, socially accessible and non-invasive method to establish blood glucose levels, it was created a linear conversion mathematical model from salivary hidrogenionic potential (pH) values to blood glucose level. After signing the informed consent form and filling out the survey questionnaire to gather personal, clinical and family history data, it was collected a drop of blood from the tip of the right index finger, which was submitted to the glucometer for blood glucose level determination and after that, it was also collected 2 mL of saliva in a 5ml glass Beacker to salivary pH definition with a digital pH meter. Data collection was performed between May and November, 2014, with a sample of 333 cappilary blood glucose (CG) and salivary ph tests from non - diabetic adult volunteers, in fasting state from 2 to 4 hours after last meal, who were randomly selected from medicine and physiotherapy clinics of UNICEUMA. After entering data in EPINFO 2000 program, results were analyzed with Pearson’s correlation coefficient (r) in Bioestat 5.3 Software and presented a value of – 0,7522, showing the existence of a correlation between capillary blood glucose and salivary pH. Then, we defined that variables were related in a mathematical form of a straight line. Thus, we found the coefficient of determination between capillary blood glucose and salivary pH using simple linear regression test: R2 = 0,5658. Regarding alpha level = 0.05, we established a mathematical model: y = a + bx, where a = 9.3286 and b = - 0.0278. So, after calculating blood glucose level from pH (pH = F (Glycemia); we have: CG = (9.3286 - pH)/ 0.0278. The results demonstrated the relation among CG values (mg/dl), corresponding salivary ph and the diagnosis respectively: CG < 70  pH > 7,94 with (Variation (Δ) = 7,784 to 8,096) = Hypoglycemic Risk; CG between 70 and 100  pH 7,94 to 6,69 = Security Gap or normality; CG > 100  pH < 6,69 with (Δ = 6,536 to 6,848) = Hyperglycemic Risk. The proposed mathematical model may allow the definition of a diagnostic kit to estimate blood glucose levels from salivary pH through a non-invasive, low-cost, socially accessible and less traumatic method either in healthy patients or at risk for developing diabetes. / A estimativa dos níveis de açúcar no sangue, por método invasivo, atualmente é rotina no atendimento de emergência e ambulatorial das unidades públicas de saúde, assim como, no controle e monitoramento glicêmico domiciliar, para prevenir variações, que podem evoluir em complicações oftalmológicas, renais, vasculares, neurológicas, entre outras. Com a finalidade de minimizar gastos e disponibilizar um kit de baixo custo, acessível e não invasivo para a determinação de níveis glicêmicos capilares, foi criado um modelo matemático linear de conversão dos valores do potencial Hidrogeniônico (pH) salivar em glicêmico capilar. Após assinatura do Termo de Consentimento livre e Esclarecido (TCLE) e preenchimento do questionário de avaliação contendo dados pessoais, clínico e de histórico familiar do paciente, coletou-se uma gota de sangue da extremidade do indicador direito, a qual foi submetida à glicosímetro para a definição do nível de glicemia, e a seguir, em um recipiente de 5 ml, coletou-se 2 ml de saliva para leitura do pH em phgâmetro digital. A coleta foi realizada entre os meses de maio a novembro de 2014, sendo a amostragem constituída por 333 exames de Glicemia Capilar (GC) e pH do fluido, de voluntários, adultos, não diabéticos, em jejum alimentar de 2 a 4 horas, os quais foram selecionados aleatoriamente, provenientes da demanda da clínica médica e de fisioterapia do UNICEUMA. Os resultados após tabulados no banco do programa EPINFO 2000 e, analisados com auxílio do Software Bioestat 5.3 a partir da aplicação do teste de correlação de Pearson apresentaram o valor de r (coeficiente de correlação) igual a – 0,7522, admitindo-se a existência de correlação entre GC e o pH salivar. Em seguida, definiu-se a forma matemática em que as variáveis estão relacionadas, nesse caso, uma reta. Desta forma, a partir da aplicação do teste de regressão linear simples obteve-se o coeficiente de determinação ou explicação da correlação entre GC e pH da saliva: R2 = 0,5658. Considerando-se o nível de decisão alfa = 0.05, estabeleceu-se um modelo matemático: y = a + bx, sendo a = 9,3286 e b = - 0,0278. Logo, calculando glicemia a partir do pH (pH = F(Glicemia); temos: GC = (pH - 9,3286)/ - 0,0278. Os resultados demonstraram a relação entre valores de GC (mg/dl), seu correspondente no pH da saliva e o diagnóstico, respectivamente: GC < 70  pH > 7,94 com (Variação (Δ) = 7,784 a 8,096) = Risco Hipoglicêmico; GC Entre 70 e 100  pH 7,94 a 6,69 = Faixa de Segurança ou normalidade; GC > 100  pH < 6,69 com (Δ = 6,536 a 6,848) = Risco Hiperglicêmico. O modelo matemático proposto pode ser utilizado para a definição de um kit de diagnóstico na estimativa dos níveis glicêmicos, a partir do pH salivar por método não invasivo, de baixo custo, socialmente acessível, com menos trauma em pacientes adultos hígidos ou com risco de desenvolver a diabetes

Thesis (Ph. D.)--University of Hong Kong, 2007. / Title proper from title frame. Also available in printed format.

The molecular basis of the potent transdermal enhancement activity of a series of iminosulfuranes, structure provided where X = H, Cl, Br, and I, is being investigated skin models. It has been shown (J. Lipid Res. 46(2005), 2192-2201.) that correlations exist between the activity of the aforementioned transdermal penetration enhancers (TPE) and the extent to which these agents bind to DMPC vesicles and perturb the gel to liquid crystal phase transition measured by calorimetry. The degree to which the perturbation of these compounds extends into the bilayer interior in contrast to surface activity is unclear. To gain insight into this issue, the 31P NMR resonance from DMPC and DMPC-cholesterol unilamellar vesicles have been split by the slowly penetrating paramagnetic metal ion Pr+3. The extent to which this perturbation is attenuated by transdermal penetration enhancers has been investigated as a function of Pr+3 exposure time and iminosulfurane concentration. The effect of these iminosulfuranes on bilayer integrity is also being explored by monitoring the induced release of carboxyfluorescein from DMPC and DMPC- cholesterol unilamellar vesicles.

Ball State University LibrariesLibrary services and resources for knowledge buildingMasters ThesesThere is no abstract available for this thesis.

Dans ce mémoire, il sera question de la formation de dérivés pipéridines en utilisant la fragmentation de Grob. Tout d’abord, une introduction sur les alcaloïdes ainsi que sur l’expertise du groupe Charette associée à leur formation démontrera l’importance de ces composés dans le domaine de la chimie organique. Cela sera suivi par un résumé de la fragmentation de Grob incluant les conditions de réactions utilisées, l’importance de la structure de la molécule initiale, les prérequis stéréoélectroniques ainsi que les modifications qui y ont été apportées. Le chapitre 2 sera dédié au développement de la méthodologie c’est-à-dire, à l’optimisation de tous les paramètres jouant un rôle dans la fragmentation de Grob. Par la suite, l’étendue de la réaction ainsi que des explications sur la régiosélectivité et la diastéréosélectivité de la réaction seront fournies. La méthodologie peut être exploitée dans un contexte de synthèse qui sera démontré dans le chapitre 3. De plus, elle servira pour une étude mécanistique qui est encore d’actualité à partir du concept d’effet frangomérique. Finalement, quelques projets futurs, notamment des améliorations possibles de la méthodologie, seront présentés dans le dernier chapitre. Le tout sera suivi d’une conclusion résumant l’ensemble des travaux effectués. / This thesis discusses the formation of piperidine derivatives using the Grob fragmentation. Firstly, an introduction of the important alkaloid family as well as previous work completed by the Charette group towards the synthesis of these compounds will be demonstrated. This will be followed by a summary of the Grob fragmentation including a discussion of the reaction conditions, molecular structures, stereoelectronic requirements and modifications of the Grob fragmentation. Chapter 2 will be dedicated to the development of the methodology and more precisely, to the optimization of all parameters necessary to the reaction. Furthermore, the scope of the reaction and some explanation of the regioselectivity and the diastereoselectivity of the reaction will be discussed. The developed methodology can be used in a total synthesis and will be demonstrated in Chapter 3. Moreover, using the frangomeric effect concept, a mechanistic study on the Grob fragmentation will be discussed. Finally, some future projects, especially possible improvement of the methodology, will be presented in the last chapter. This is followed by a conclusion and a summary of the work completed on this project.

The use of standard soil tests to assess waste materials has become a common practice in waste management. However, the suitability of using standard soil tests on waste materials is questionable. Therefore, this investigation was undertaken to compare commonly used chemical extraction methods for their ability to extract elements from soil, waste, and soil-waste mixtures. This was carried out by: · Assessing the effects of extraction time on the extractability of Al,Ca, Co, Cu, Fe, Mg, Mn, Ni, Pb, S, Si, and Zn; · Assessing the comparability between single and sequential extraction. Two manganese rich wastes namely electro-winning waste (EW) and silicate-rich smelter slag (SS) and an acid soil (Inanda, Ia) were used for this study. Waste amended soils were obtained by incubating the EW and SS with Ia soil at field capacity at a rate of 20 g kg-1 and 120 g kg-1 soil respectively, and were sampled at day 0, 7, 28, 56, and 140. The effect of extraction time was assessed on the EW, SS, and Ia soil with carbonated water used in the acid rain test conducted at 16, 20, 30, and 50 hours. The equilibration time was different for different materials and elements. The concentration of Al and Zn did not change appreciably with increasing extraction time in the EW. Similar results were found for Mg, S, and Si in the SS and S in the Ia soil. This was attributed to ‘equilibrium’ being reached before 16 hours. The equilibration time of 20 hours which would release the exchangeable and specifically adsorbed elements was obtained for Co, Mg, Si, S, and Mn in the EW. The concentration of Ca decreased with extraction time in the EW and was attributed to readsorption. The concentration of Ca and Mn in the SS and Al, Fe, and Si in the Ia soil increased with extraction time and the ‘equilibrium’ was not reached even after 50 hours. This was attributed to the release of elements due to dissolution of minerals. In the comparison between Community Bureau of Reference (BCR) sequential and batch extraction, the concentrations of Ca, Co, Mg, Mn, and S were higher in batch extraction than in sequential extraction, particularly for the EW and the EW treated soils. This was possibly caused by the readsorption of released elements during water extraction. On the contrary, sequential extraction had higher concentration of Al and Fe compared to batch extraction for the EW, Ia soil, SS treated soils, and EW treated soils. These were attributed to a continued desorption of elements and dissolution of minerals due to exposed surfaces which occurs in sequential extraction. The comparison between single and sequential extraction for the BCR sequential extraction showed that hydroxylammonium chloride (HAC) applied in sequential extraction had higher concentration of Al, Co, Fe, Pb, and Zn than the single HAC extraction. This was probably due to incomplete dissolution of minerals, precipitation of amorphous minerals, and readsorption of released elements occurring for a single HAC extraction. These were minimised for hydrogen peroxide (H2O2) extraction and hence comparability between single and sequential H2O2 extraction was observed. This was probably due to the presence of complexing agent in the extracting reagent which would minimise the formation of secondary precipitates and hence, improved dissolution of minerals was obtained. Similarly, the concentrations of elements were comparable between single and sequential aqua regia extraction. These results indicated that comparability is improved between single and sequential extraction when aggressive conditions are used. The results from this investigation indicated that when chemical extraction methods are applied to wastes, the effects of the waste properties on the results of extraction need to be well understood. Consequently, when the chemical extraction methods are used in waste management scenarios certain modifications might have to be made. These modifications include the use of a high solution:solid ratio and an extracting solution which has high complexing ability / Thesis (M.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2010.

There is no abstract available for this thesis. / Department of Chemistry