In recent years the application of single-molecule techniques to probe biomolecules and intermolecular interactions at single-molecule resolution has expanded rapidly. Here, I investigate a series of peptides and proteins in an attempt to gain a better understanding of nanopore sensing as a single-molecule technique. The analysis of retro, inversed, and retro-inversed isomers of glucagon and α-helical Fmoc-D2A10K2 peptide showed that nanopore sensing utilizing a wild-type α-hemolysin pore can distinguish between all four isomers while circular dichroism can only distinguish between chiral isomers, but not between directional isomers. The investigation of a series of proteins of different chemical and physical properties revealed important information about nanopore analysis of proteins. Contrary to some reports in the literature, all proteins analysed here induced large blockade events. The frequency of total events and the proportion of large blockade events were significantly reduced in tris(hydroxymethyl)aminomethane or 4-(2-hydroxyethyl)piperazine-1-ethanesulfonic acid buffers and were only restored by the addition of ethylenediaminetetraacetic acid or the use of phosphate buffer, both of which can sequester metal ions. Furthermore, the results obtained with the proteins in the presence of ligands demonstrated that transient or partial unfolding of proteins can be detected by nanopore analysis confirming the usefulness of this technique for conformational studies or for protein/ligand interactions. Interestingly, while the blockade current histograms were different for each protein there was no obvious correlation between the properties of the proteins and the blockade current histograms. In an attempt to identify whether the large blockade events were translocation or intercalation, both an indirect and a direct approach were taken. The indirect approach which relies on the effect of voltage on the interaction of the molecule with the pore provided no conclusive answer to the question of protein translocation through the α-hemolysin pore. In contrast, the direct approach in which ribonuclease A is added to the cis side of the pore and then the trans side is tested for enzyme activity showed that ribonuclease A doesn't translocate through the α-hemolysin pore.

Pheroid is a patented system comprising of a unique submicron emulsion type formulation. Pheroid vesicles consist mainly of plant and essential fatty acids and can entrap, transport and deliver pharmacologically active compounds and other useful molecules. The aim of this study was to show that a modulation of components and parameters is necessary to obtain the optimum formula to be used in pharmaceutical preparations. Non-optimal or non-predictable stability properties of emulsions can be limiting for the applications of emulsions (Bjerregaard et al., 2001:23). Careful consideration was given to the apparatus used during the processing along with the ratios of the various components added to the formulation and the storage conditions of the Pheroid vesicles. A preliminary study was performed to optimize the most accurate processing parameters during emulsification. The effect of emulsification rate and time, the temperature of the aqueous phase, the number of days the water phase were gassed, the concentration of the surfactant, cremophor® RH 40, used and the concentration of Vitamin F Ethyl Ester CLR added to the oil phase of the o/w emulsion has been studied. Quantification of the mean particle size, zeta potential, turbidity, pH and current values were used to characterize the emulsions. The samples were characterised after 1, 2, 3, 7, 14, 21 and 28 days of storage. The emulsions were also characterised with confocal laser scanning microscopy (CLSM) to measure the number and size and size distribution of the vesicles. After determination of the processing variables influencing the emulsion stability an accelerated stability test was conducted on a final formula. In the present study, accelerated stability testing employing elevated temperatures and relative humidity were used with good accuracy to predict long-term stability of an o/w emulsion kept at both 5 and 25 OC with 60 % relative humidity and 40 OC with 75 % relative humidity. The results of the stability tests were presented in histograms of the physical properties 24 hours, 1 month, 2 months and 3 months after preparation of the emulsion. It was concluded that Pheroid vesicles demonstrate much potential as a drug delivery system. The high stability of this formula allows its use in a wide variety of applications in the pharmaceutical industry. / Thesis (M.Sc. (Pharmaceutics))--North-West University, Potchefstroom Campus, 2007.

Pheroid is a patented system comprising of a unique submicron emulsion type formulation. Pheroid vesicles consist mainly of plant and essential fatty acids and can entrap, transport and deliver pharmacologically active compounds and other useful molecules. The aim of this study was to show that a modulation of components and parameters is necessary to obtain the optimum formula to be used in pharmaceutical preparations. Non-optimal or non-predictable stability properties of emulsions can be limiting for the applications of emulsions (Bjerregaard et al., 2001:23). Careful consideration was given to the apparatus used during the processing along with the ratios of the various components added to the formulation and the storage conditions of the Pheroid vesicles. A preliminary study was performed to optimize the most accurate processing parameters during emulsification. The effect of emulsification rate and time, the temperature of the aqueous phase, the number of days the water phase were gassed, the concentration of the surfactant, cremophor® RH 40, used and the concentration of Vitamin F Ethyl Ester CLR added to the oil phase of the o/w emulsion has been studied. Quantification of the mean particle size, zeta potential, turbidity, pH and current values were used to characterize the emulsions. The samples were characterised after 1, 2, 3, 7, 14, 21 and 28 days of storage. The emulsions were also characterised with confocal laser scanning microscopy (CLSM) to measure the number and size and size distribution of the vesicles. After determination of the processing variables influencing the emulsion stability an accelerated stability test was conducted on a final formula. In the present study, accelerated stability testing employing elevated temperatures and relative humidity were used with good accuracy to predict long-term stability of an o/w emulsion kept at both 5 and 25 OC with 60 % relative humidity and 40 OC with 75 % relative humidity. The results of the stability tests were presented in histograms of the physical properties 24 hours, 1 month, 2 months and 3 months after preparation of the emulsion. It was concluded that Pheroid vesicles demonstrate much potential as a drug delivery system. The high stability of this formula allows its use in a wide variety of applications in the pharmaceutical industry. / Thesis (M.Sc. (Pharmaceutics))--North-West University, Potchefstroom Campus, 2007.

Made available in DSpace on 2015-05-14T12:56:03Z (GMT). No. of bitstreams: 1 arquivototal.pdf: 2756793 bytes, checksum: 52c334e99949464b4e3237ddf1e202c6 (MD5) Previous issue date: 2014-02-25 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The transport of materials through the tooth enamel is conventionally derived from the diffusion process, which leads to a number of limitations, because the pores of the enamel are extremely small, requiring a certain extension, as occurs in adhesive techniques by the etching process. An alternative method to this technique is the electrokinetic flow (EKF), which promotes the unidirectional flow of substances through the pores of the enamel by applying an external electric field. Based on this premise it was promoted the infiltration of a composite resin with low viscosity (Icon DMG, Hamburg, Germany) on the surface of 20 extracted human teeth by EKF, using an electric field (1.5V) in two stages: (1) infiltration of potassium chloride 0.1M (KCl) during 3h and (2) infiltration of the resin during 2h. Longitudinal histological sections of &#8776; 100&#956;m were analyzed by fluorescence microscopy and polarized light microscopy associated with the "polscopesingle"system, after 24h of dehydration and along 50, 100, 150, 200, 250, 300, 350, 400, 450 and 500&#956;m deep. Electric voltage (&#956;A) presented to be positive during infiltration. Images from Fluorescence Microscopy revealed fluorescence of the infiltrated enamel areas for all samples, from the surface to the dentin-enamel junction (DEJ), indicating the formation of a hybrid layer with average depth of 1627.66 &#956;m and a standard deviation of 284.20 &#956;m. The records of the phase delay during dehydration of the infiltrated and non-infiltrated areas did not present changes in the infiltrated area. It was observed that the water was replaced by the resin (p<0.000001), with high effect size (>0.8). Based on these results, it was concluded that the EKF resulted in infiltration of the resin into the enamel nanochannels. / O transporte de materiais através do esmalte dentário é limitado já que convencionalmente depende do processo de difusão, em virtude do volume nanométrico dos poros do esmalte. Um método alternativo pode ser o uso do Fluxo Eletrocinético (FEC), que promove o fluxo unidirecional de substâncias através dos poros do esmalte pela aplicação de um campo elétrico externo. Por conseguinte, este estudo promoveu a infiltração de resina fluida na superfície de 20 dentes humanos extraídos através do FEC, utilizando um campo elétrico de 1,5 volt em duas etapas: (1) infiltração de Cloreto de Potássio (KCl) 0,1M por 3h (2) infiltração da resina Icon (DMG, Alemanha) por 2h. Cortes histológicos por desgaste com &#8776; 100&#956;m foram analisados por Microscopia de Fluorescência (MF) e por Microscopia de Luz Polarizada (MLP) associada ao sistema single polscope , durante a desidratação das amostras por um período de 24h e analisando pontos histológicos a 50, 100, 150, 200, 250, 300, 350, 400, 450 e 500&#956;m a partir da superfície de áreas infiltradas e não infiltradas. A variação da corrente elétrica (mA) mostrou-se positiva durante a infiltração. As imagens da MF demonstraram fluorescência do esmalte na região infiltrada desde a superfície até a junção amelo-dentinária (JAD), indicando a formação de uma camada híbrida com profundidade média de 1627,66 &#956;m e desvio padrão de 284,20 &#956;m. Comportamentos distintos foram identificados para as áreas infiltrada e não infiltrada durante a desidratação. A área não infiltrada perdeu água, conforme verificado através da redução do retardo de fase. A área infiltrada não perdeu água, uma vez que o retardo manteve-se constante, sugerindo que a água fracamente aderida foi substituída pela resina durante a infiltração. As diferenças estatísticas entre os pontos histológicos das duas áreas foram calculadas através do teste de Mann-Whitney, com nível de significância de 5%, confirmando que a água foi substituída pela resina (p< 0,000001), com alta magnitude do efeito (>0,8). Portanto, pode-se concluir que a utilização do FEC resultou na infiltração da resina nos nanocanais do esmalte, formando camada híbrida de grande profundidade.

Thesis is indirectly connected to many years of research in field of sulphate binders. Work is focused on modifying of properties of alfa and beta gypsum, mainly on reduction of water ratio. We monitored effect of addition of chloride salts, carbonates and sulphates on zeta potential and its measurement. Part of thesis is also focused on laboratory production of beta plaster from secondary materials and optimization of grinding process to achieve required criteria.

Charles University Faculty of Pharmacy in Hradcec Králové Department of Pharmaceutical Technology Supervisor: doc. RNDr. Milan Dittrich, CSc. Student: Simona Medviďová Title of thesis: Formulation and testing of branched polyesters siRNA-loaded nanoparticles The progression of development increases demand for new and more effective drug systems formulations. This diploma thesis is focused on the preparation of nanoparticles from biodegradable branched polyesters based on PLGA, which are suitable for the transport of an oligonucleotide of a small interfering nucleic acid, siRNA. The theoretical part focuses on the characteristics of usable polymers, their possible modifications, the methods of preparation with closer look at the selected nanoprecipitation method, the important parameters such as particles size, zeta potential, and polydispersity. The main part is also characterization of siRNA in terms of structure, properties, modifications, and its function. A more extensive experimental part deals with the appropriate choice of type and concentration of polyester and stabilizer, methods of preparation and characterization of nanoparticles, and the possibility of analyzing encapsulated siRNA. Chapters results and discussion compares polyesters branched on tripentaerythritol, and polyacrylic acid...

[pt] Os minérios de cobre-molibdênio são beneficiados juntos normalmente pelo processo de flotação com a ajuda de coletores sulfidrílicos de relativa seletividade. Os concentrados bulk obtidos devem ser processados com o intuito de remover aqueles coletores empregados, pois eles são prejudiciais na etapa de separação por flotação diferencial, ou seja, na obtenção de concentrados de molibdênio de alta qualidade com baixos conteúdos de cobre e ferro. O processo de flotação bulk é realizado em condições oxidantes na presença de coletores sulfidrílicos (xantatos, etc.). Na prática industrial na etapa de flotação diferencial, estes concentrados bulk são separados por modificação do potencial eletroquímico da polpa para valores considerados redutores -300 a -450 mV, com hidrosulfeto de sódio (NaSH) ou o reagente Nokes (Penta-sulfeto de fósforo dissolvido em hidróxido de sódio) além de cianeto de sódio em alguns dos casos, para melhorar a eficiência do processo. Neste quadro, o processo industrial de separação seletiva produz efluente e gases perigosos como o H2S e HCN que devem ser controlados adequadamente. Este trabalho visa avaliar o uso do reagente ácido pseudo glicol tiouréia (PGA) e ácido tioglicólico (TGA) como alternativas ao processo industrial voltado para a separação seletiva dos minerais de cobre e molibdênio. Para a avaliação do depressor foram empregadas medições de ângulo de contato, potencial zeta, testes de flotação em célula Partridge-Smith (PS), FTIR e testes em célula de bancada em um planejamento experimental. O reagente estudado apresentou boas propriedades depressoras para minerais de cobre. Nos resultados das medições de ângulo de contato, pelo método de bolha cativa, foram encontrados valores maiores para a calcopirita do que para a molibdenita (até 10 graus de diferença) e medidas entre 60 e 70 graus, porém no pH ácido esta diferença diminui e os dois minerais apresentam quase o mesmo ângulo de contato 60 mais ou menos 1 grau. Nas medidas efetuadas não foi empregado o coletor final (querosene) para a molibdenita devido a sua falta de homogeneidade na emulsão para realizar as medidas de ângulo de contato. Nos testes de flotabilidade na célula PS em misturas binarias de calcopirita-molibdenita foram encontradas na faixa ácida, valores de pH nos quais há melhores relações de concentração e recuperações, na ordem de 67 por cento para a molibdenita e apenas 10 por cento para a calcopirita no produto flutuado. Os resultados usando o reagente NaSH em condições similares apresentam recuperações similares de molibdenita, mas na faixa básica do pH. Baseados nestes resultados foram avaliadas diversas variáveis e gerado um planejamento experimental para passar à escala de bancada onde foram obtidas recuperações de 84 por cento no concentrado rougher com apenas 13 por cento de cobre corroborando as boas propriedades do depressor estudado. / [en] Copper-molybdenum porphyry deposits worldwide are exploited industrially by flotation of the ores of interest into a BULK concentrate with the aid of sulfhydryl collectors of high efficiency and low selectivity. The bulk concentrate obtained should be reprocessed in order to remove those collectors employed in the bulk stage since they impair the differential flotation during the separation step in order to obtain clean high quality molybdenite concentrates at low contents of copper and iron. The bulk flotation process is conducted under oxidizing conditions in presence of sulfhydryl collectors (xanthates, etc.). In industrial practice these bulk concentrates are then separated by modification of the pulp electrochemical potential to values considered reducing, between -300 to-450 mV, with sodium hidrosulphide (NaSH) or Nokes reagent (phosphorus pentasulfide dissolved in sodium hydroxide). Addition of sodium cyanide in some cases is used to improve process efficiency. Bulk concentrates produced are however a very small portion of the processed mineral (only 1/50 of the total ore milled), these industrial processes produce waste effluents and hazardous gases such as H2S and HCN if not adequately controlled. This dissertation seeks to assess the reagent pseudo glycol tiourea acid (PGA) and thioglycolic acid (TGA) as an alternative to industrial processing for the selective separation of minerals of copper and molybdenum. On the evaluation of this depressant were used contact angle measurements, zeta potential, flotation tests in Partridge-Smith cell (PS), FTIR and bench scale flotation testing cell with an experimental design. The reagent studied showed good depressant properties for copper minerals according to the results presented. Within the results of the contact angle measurements with the captive bubble technique were found greater contact angles for chalcopyrite than for molybdenite (up to 10 degrees difference) and values between 60 and 70 degrees, however in acidic pH this difference decreases and both minerals have almost the same contact angle as of 60 more or less 1 degree. Though on the contact angle measured values it was not employed the final collector (kerosene) for molybdenite due to lack of homogeneity on emulsions to make the contact angle measurements. On floatability tests (on PS cell) with binary mixtures of chalcopyrite-molybdenite were found pH values on the acidic range, at which good concentration ratios and recoveries in the order of 67 percent of molybdenite with only 10 percent of the chalcopyrite were obtained. The results using NaSH reagent under similar conditions gave similar recoveries for molybdenite, however it was found in the basic pH range. Based on the results, several variables were evaluated and an experimental design employed on bench scale flotation tests, the results showed recoveries of 84 percent were obtained in the rougher concentrate with 13 percent copper corroborating the good properties of this depressant.

Le procédé actuel de fabrication des combustibles nucléaires MOX (UO2-PuO2) est réalisé exclusivement par voie sèche (broyage-tamisage des poudres, pressage et frittage). Afin d’améliorer ce procédé, des recherches sont menées sur le développement d’un procédé de fabrication du MOX par voie liquide. Ce procédé vise à réduire l’empoussièrement des boîtes à gants, améliorer l’homogénéité U/Pu et diminuer la quantité de défauts (fissures, éclats) des pastilles frittées, afin de minimiser le taux de pastilles rebutées. Dans cette optique, le proceed voie liquide étudié consiste à préparer une suspension aqueuse à partir des poudres brutes d’oxydes (mélange d’eau, d’additifs organiques et de poudres), puis à lui faire subir une granulation. Les granules obtenus sont ensuite pressés et frittés. Le procédé de granulation étudié est un procédé innovant de granulation cryogénique, consistant à atomiser la suspension dans de l’azote liquide puis à lyophiliser les granules gelés ainsi formés. L’étape clé du procédé est la préparation de suspension aqueuse de poudres UO2-PuO2, qui doit être dispersée, homogène, stable et suffisamment fluide pour l’étape de granulation. Une étude préliminaire a été réalisée avec des poudres simulantes, choisies pour leurs propriétés en suspension : TiO2 et Y2O3 pour simuler respectivement UO2 et PuO2. Une fois maîtrisé avec les poudres simulantes, ce procédé a été étudié avec UO2 et PuO2 pour déterminer ses conditions optimales de mise en oeuvre. La dispersion de suspensions d’UO2 et/ou de PuO2 a été étudiée par acoustophorométrie et rhéologie afin d’optimiser leur formulation, ainsi que l’étape de granulation cryogénique. Enfin, des pastilles d’UO2 et d’UO2-PuO2 ont été formées à partir des granules, puis leur frittage et leur microstructure ont été étudiés. / The current manufacturing process for MOX nuclear fuels (UO2-PuO2) is carried out by dry route exclusively (grinding, sieving, pressing and sintering). In order to improve this process, research is conducted to develop a liquid route MOX manufacturing process. It aims to reduce glove boxes dusting, increase U/Pu homogeneity and reduce the amount of defects (cracks, voids) in sintered pellets, in order to minimize scraps. In this scope, the liquid process studied consists in the preparation of an aqueous suspension from the raw oxide powders (mix of water, organic additives and powders), which is then granulated. The resulting granules are pressed into pellets and sintered. The granulation process studied is an innovative freeze granulation process that implies to spray the suspension in liquid nitrogen and then freeze-dry the frozen granules that are formed.The key step of the process is the preparation of aqueous suspension of UO2-PuO2 powders, which must be dispersed, homogeneous, stable and fluid enough for the granulation step. A preliminary study was carried out using surrogate powders, chosen for their properties in suspension: TiO2 and Y2O3 to surrogate UO2 and PuO2 respectively. Once mastered with surrogate powders, this process was studied with UO2 and PuO2 to determine its optimal working conditions. The dispersion of UO2 and/or PuO2 suspensions was studied by acoustophorometry and rheology in order to optimize their formulation, as well as the freeze granulation step. Finally, UO2 and UO2-PuO2 pellets were shaped from the granules, and their sintering and microstructure were studied.

Charles University Faculty of Pharmacy in Hradec Králové Department of Pharmaceutical Technology Consultant: doc. RNDr. Milan Dittrich, CSc. Student: Andrea Balciarová Title of Thesis: Formulation and testing of rifampicin-loaded branched polyesters nanoparticles In presented thesis, the main attention in theoretical part is focused on nanoparticles for targeted drug delivery, their types, structure and carriers used for their preparation. Moreover, in this part there is an overview of physicochemical characteristics and preparation methods of polymeric nanoparticles applicable in formulation of pharmaceutical products. The experimental part is concerned on studying the influence of the concentration of biodegradable polymers, the presence of cationic surfactants and rifampicin as model drug substance on nanoparticles΄ size and zeta-potential. The main attention is given to nanoparticles decoration with anionic biopolymers, hyaluronic acid and xanthan gum. The simple method of preparation which is usable in nanosystems formulation that influence biological functions purposefully was tried and tested in different contexts.

Thesis title: Formulation and characterization of oxime loaded PLGA nanoparticles Author: Ramin Hafezi Supervisor: PharmDr. Eva Šnejdrová, Ph.D. Advisor: PharmDr. Juraj Martiška, Ph.D. Department: Department of Pharmaceutical Technology The diploma thesis was focused on PLGA nanoparticles (NPs) which could be loaded with oximes, prepared by a double emulsion technique, and characterised by size, polydispersity and zeta potential. The theoretical part deals with the most common methods of the NPs preparation, the polymers and stabilizers employed, and drug delivery to brain. In the experimental part the effect of various formulation factors on NP characteristics were studied: linear or branched PLGA derivative, the concentrations of polymer, the volumes of primary emulsion. Dichloromethane (DCM) or Dimethyl sulfoxide (DMSO) as solvent for polymers were used and Poloxamer 407 or Didodecyldimethylammonium bromide (DDAB) as an outer phase stabilizer were employed. By comparison among the collected results, it seemed 1% A2 in DMSO and stabilization with poloxamer 407 could be best candidate for the oxime loaded drug delivery systems as it was possible to produce nanoparticles with size from 152 to 168 nm with PDI of below 0.15. Electrostatic stability in case of using DDAB was resulted excellent and...