This dissertation has focused on studying the effect of four glycine derivatives on the solid state properties of mannitol, glycine, and sucrose when freeze dried into blended mixtures. The primary goal was to assess their value for use in the stabilisation of vaccines in the solid state, by examining key physical and chemical characteristics, which have been documented to be beneficial to the stabilisation of biopharmaceutical formulations. The novel excipients; dimethyl glycine, and trimethyl glycine, were shown to retard the crystallisation and increase the overall glass transition temperature, of mannitol, when freeze dried as evidenced by DSC and Powder X-ray diffraction. Mannitol’s glass transition temperature increased from 100C to 12.650C and 13.610C when mixed with methyl-glycine and dimethyl glycine respectively. The glycine derivatives did not show the same effect on sucrose which remained amorphous regardless of the concentration of the other excipient. The different behaviour with the sucrose system was thought to be due to relatively high glass transition temperature of sucrose. Conversely glycine remained highly crystalline due it’s relatively low glass transition temperature. The novel excipient formulations were also assessed for their effect on the aggregation of the adjuvant aluminium hydroxide when freeze dried by Dynamic Light Scattering (DLS).The formulations containing the glycine derivatives all caused a decrease in the aggregation size of the adjuvant from ~26 μm, to 185 nm in the presence of methyl glycine. The effects of lysozyme and viral antigen on the adjuvants were also examined showing that the addition of the virus did not affect the size of the aggregates formed, however lysozyme showed significant decreases in the aggregates formed. Examination of the freezing method were also made showing that faster freezing rates produced smaller aggregates of the adjuvant. When investigating the rate at which the excipients lost water during secondary drying there was evidence of the formation of hydrates of glycine, trimethyl glycine, and mannitol has shown that the glycine derivatives have attributes which would be beneficial in stabilising vaccines in the solid state when freeze dried.

Um polieletrólito catiônico (poliamina), com baixo peso molecular e elevada densidade de carga, normalmente aplicado como agente coagulante do lixo aniônico, foi usado para estudos de retenção e drenagem na fabricação de papel. O uso do carboximentil celulose de sódio para simulação do teor de lixo aniônico e seu efeito na retenção de cargas minerais foi uma característica importante para este trabalho. Pode ser observado que o aumento da dosagem do polímero catiônico tanto melhora a retenção de cargas minerais, avaliada pela turbidez do filtrado, quanto melhora a drenagem do sistema, avaliada pela velocidade de escoamento. Entretanto, elevadas dosagens deste polímero comprometeram os resultados destes parâmetros devido à inversão de carga do sistema. Pode também ser confirmado que forças de cisalhamento excessivas prejudicam a retenção de cargas minerais. Ademais, um polianfótero, com peso molecular e densidade de carga elevados, contendo grupos positivo (N-[3-(N,N-dimetilamino)propil]acrilamida), negativo (ácido metileno butanodióico) e nulo (acrilamida) na mesma cadeia, foi testado como agente de resistência a seco do papel. Todos os estudos em nível molecular sobre o comportamento do polianfótero em solução e o seu comportamento de adsorção sobre superfícies modelos carregadas, em diferentes condições de pH e de força iônica, foram importantes para explicar tanto dos fenômenos de adsorção, envolvendo fibras celulósicas e polianfótero, quanto o seu efeito na resistência mecânica do papel. Foi observado que a solubilidade do polímero aumenta à medida que o pH se distancia do seu ponto isoelétrico, pHPIE 7,3, e reduz para valores de pH próximos ao pHPIE. O tamanho das estruturas do polianfótero depende do pH do meio de dispersão. As características de tamanho do polianfótero tanto sob a forma de cadeias individuais ou quanto sob a forma de agregados, foram medidas através da técnica de espalhamento dinâmico de luz. As propriedades viscoelásticas das camadas adsorvidas e a quantidade de polímero adsorvida foram medidas através da técnica da balança microgravimétrica com dissipação de energia. Estas duas determinações, associadas às imagens no microscópio de força atômica, foram importantes para o entendimento dos resultados práticos do uso do polianfótero como agente de resistência a seco do papel. Maiores resultados de resistência do papel, avaliada através da resistência à tração, foram alcançados para valores de pH próximos ao ponto isoelétrico onde foram encontrados o seguinte: (1) maiores tamanhos para as estruturas do polímero em solução, (2) maior quantidade de massa nas camadas adsorvidas e (3) a formação de camadas mais viscoelásticas. O fenômeno de separação de fases, associado à mudança da solubilidade do polímero em solução devido ao balanço dos grupos positivos e negativos ionizados ao longo da faixa de pH estudada, foi considerado o principal aspecto para a variação em tamanho dos agregados. Embora este polímero tenha apresentado comportamento antipolieletrólito devido à expansão da sua cadeia e ao aumento da densidade de carga com o aumento da força iônica, considerando o efeito da força iônica para pH 4,3, o comportamento de adsorção do polianfótero foi avaliado como o comportamento de um polieletrólito monocarregado de alta densidade de carga. Maiores e menores quantidades de massas adsorvidas foram encontradas para valores intermediários e extremos de força iônica, respectivamente. As interações eletrostáticas foram consideradas as principais responsáveis pela adsorção do polímero sobre superfícies carregadas. Entretanto, a blindagem de cargas foi considerada a explicação para os baixos valores de massa adsorvida para valores mais elevados de força iônica. / A cationic polyelectrolyte (polyamine), with low molecular weight and high charge density, usually applied as anionic trash coagulant, was used for the retention and drainage studies in the papermaking. The use of sodium carboxymethyl cellulose to simulate the anionic trash content and its effect on the filler retention was an important feature of the work. It could be noted that the increasing of the cationic polymer dosage improves both the filler retention, evaluated by the turbidity of the filtrate, and the system drainage, evaluated by the flow speed. However, high dosages of this polymer compromised the results of these parameters due to the reversal of the system charge. It can also be confirmed that excessive shear forces affect the filler retention. Furthermore, a polyampholyte, with high molecular weight and charge density, containing positive (N-[3-(N,N- dimethylamino)propyl]acrylamide), negative (methylene butanedioic acid), and neutral (acrylamide) groups in the same chain, was tested as a dry strength agent. All of the studies at molecular level concerning to the polyampholyte behavior in the solution and its adsorption behavior on charged model surfaces at different conditions of pH and ionic strength, were important to explain both the adsorption phenomena, involving cellulosic fibers and polyampholyte, and its impact on the paper strength. It was observed that the polymer solubility increases as the pH moves away from its isoelectric point, pHIEP 7.3, and decreases when the pH approaches close to pHIEP. The sizes of the structures of the polyampholytes depend on the pH of the dispersion medium. Also the size characteristics of polyampholyte, both in individual and aggregated forms, were measured by dynamic light scattering technique. The viscoelastic properties of adsorbed layers, as well as the amount of the adsorbed polymer, were measured by quartz crystal microbalance technique with energy dissipation. These two measurements, associated with the atomic force microscopy images, were important to understand the practical results of polyampholyte usage as a dry strength agent. Best results of paper strength, evaluated by paper strength index, were achieved at pH close to the isoelectric point on which one were found the following features: (1) larger sizes of the polymer structures in solution, (2) higher amount of mass in the adsorbed layers, and (3) the formation of more viscoelastic layers. The phase separation phenomenon, associated with the change in the solubility of the polymer due to the balance of the positive and negative groups throughout the studied pH range, was considered the main aspect for the variation in size of the aggregates. Although this polymer shows antipolyelectrolyte behavior due to the expansion of the its chain and the increasing in charge density with the ionic strength, considering the effect of ionic strength at pH 4.3, the adsorption behavior of polyampholyte was evaluated as a monocharged polyelectrolyte behavior with high charge density. Major and minor amounts of adsorbed masses were found for intermediates and extremes values of ionic strength, respectively. The electrostatic interactions were considered the main cause of the adsorption on charged surfaces. However, the electrostatic screening was considered the explanation for the low values of adsorbed mass at higher values of ionic strength.

The mechanochemical polycondensation between a diamine and a dialdehyde constitutes a sustainable alternative to classical solvent-based polymerization reactions. This process not only allows for a higher conversion and a shorter reaction time as compared to standard solvent-based syntheses of this conjugated polymer, but the reaction can also be adjusted by the energy introduced via the ball mill.

The presented doctoral thesis is focused on preparation, characterization and application of organic micro- and nanoparticles as transport systems for active components and some their complex natural sources. Active component were packed into liposomes and polysaccharide particles. As active components were used caffeine, some drugs – clotrimazole and ibuprofen, further antioxidants and vitamins. Antimicrobial herbs and spices extract, antimicrobial peptides lysozyme, nisin and other antimicrobial ingredients were encapsulated too. Encapsulation of selected hydrolytic enzymes was tested, too. Particles were also used for encapsulation of probiotic strains Bifidobacterium breve and Lactobacillus acidophilus and prebiotic components. These prebiotics were co-encapsulated into capsules with probiotic cells. Natural extracts were encapsulated e.g. extracts of guarana, ginseng, goji, green barley, propolis, black, green and white tea, coffee, fruit and vegetable extracts. The efficiency of encapsulation was determined by HPLC/PDA and by spectrophotometry. Long-term stability of particles and amount of released component in model/real foods, in model cosmetic conditions and in a model physiological environment were monitored too. Size of prepared liposomes and polysaccharide particles was determined by dynamic light scattering and by light microscopy and electron microscopy, respectively. Stability of the particles was measured using a zeta potential. Also, analytical centrifugation was used to measurement of sedimentation velocity and stability of the prepared particles. The antimicrobial activity were tested using two Gram-positive (Bacillus subtilis, Micrococcus luteus), two Gram-negative (Escherichia coli, Serratia marcescens) bacteria and one fungal strains (Candida glabrata). For determining the antimicrobial properties of active component and prepared particles two the most widely used methods were used - agar diffusion method and broth dilution method. The viability of probiotic strains were performed using flow cytometry and fluorescence microscopy. Encapsulation of active component was successful in all types of particles. Liposome showed a very good long-term stability mainly in water conditions with neutral pH and polysaccharide particles were stable in acidic conditions. Prepared particles showed a very good stability in model stomach environment, while in model intestines environments particles were disintegrated and active component were released. Prepared particles with encapsulated caffeine as well as other tested antioxidants and vitamins could be used to modern types of energy drinks, food supplements and also for some cosmetics applications. Encapsulated antimicrobial components could be used for food application as well as for cosmetics and pharmaceutical application like antimicrobial wound formulation. Encapsulated enzymes can be used for controlled release of proteases in wound healing, as delivery systems in digestive tract and as a part of pharmaceutical preparative and food supplements for enzyme therapy. The study revealed that encapsulation of probiotics and also co-encapsulation of probiotics with prebiotics exhibited longer stability of particles and survival bacterial cells. So, prepared particles are suitable for use to food product with beneficial effects on the human body.

Předkládaná diplomová práce se zabývá extrakcí nanočástic oxidu titaničitého z produktů osobní péče, konkrétně opalovacích krémů a následnou charakterizací těchto částic. Počet komerčně dostupných produktů s obsahem nanočástic TiO2 se neustále zvyšuje a to se sebou přináší potřebu vyhodnotit potenciální osud a nepřímou expozici TiO2 nanošástic o různých velikostí a tvarů a zkoumat jejich celý životní cyklus. Bylo zkoumáno použití ultrafiltrace a ultracentrifugace jako extrakční metody. Dvě metody pro extrakci TiO2 nanočástic byly vyvinuty a aplikovány na vzorky opalovacích krémů. Extrahované částice mohou být použity pro ekotoxikologické studie, případně experimenty v mesokosmu. Velikost částic byla stanovena pomocí metody dynamického rozptylu světla a transmisní elektronové mikroskopie.

<div>Large protein molecules are abundant in biological cells but are very difficult to study in physiological conditions due to molecular disorder. For large proteins, most structural information is obtained in crystalline states which can be achieved in certain conditions at very low temperature. X-ray and neutron crystallography methods can then be used for determination of crystalline structures at atomic level. However, in solution at room or physiological temperatures such highly resolved descriptions cannot be obtained except in very few cases. Scattering methods that can be used to study this type of structures at room temperature include small-angle x-ray and neutron scattering. These methods are used here to study two distinct proteins that are both classified as glycoproteins, which are a large class of proteins with diverse biological functions. In this study, two specific plasma glycoproteins were used: Fibrinogen (340 kDa) and Alpha 1-Antitrypsin or A1AT (52 kDa). These proteins have been chosen based on the fact that they have a propensity to form very large molecular aggregates due to their tendency to polymerize. One goal of this project is to show that for such complex structures, a combination of scattering methods that include SAXS, SANS, and DLS can address important structural and interaction questions despite the fact that atomic resolution cannot be obtained as in crystallography. A1AT protein has been shown to have protective roles of lung cells against emphysema, while fibrinogen is a major factor in the blood clotting process. A systematic approach to study these proteins interactions with lipid membranes and other proteins, using contrast-matching small-angle neutron scattering (SANS), small angle x-ray scattering (SAXS) and dynamic light scattering (DLS), is presented here. A series of structural reference points for each protein in solution were determined by performing measurements under osmotic stress controlled by the addition of polyethylene glycol-1,500 MW (PEG 1500) in the samples. Osmotic pressure changes the free energy of the molecular mixture and has consequences on the structure and the interaction of molecular aggregates. In particular, the measured radius of gyration (Rg) for A1AT shows a sharp structural transition when the concentration of PEG 1500 is between 33 wt\% and 36 wt\%. Similarly, a significant structural change was observed for fibrinogen when the concentration of PEG 1500 was above 40 wt\%. This analysis is applied to a study of A1AT interacting with lipid membranes and to a study of fibrinogen polymerization in the presence of the enzyme thrombin, which catalyzes the formation of blood clots. The experimental approach presented here and the applications to specific questions show that an appropriate combination of scattering methods can produce useful information on the behavior and the interactions of large protein systems in physiological conditions despite the lower resolution compared to crystallography.</div>

A non-reactive model system comprising a highly concentrated and unstable oil-in-water emulsion was used to investigate the retention of oil by the membrane in producing biodiesel with a membrane reactor. Critical flux was identified using the relationship between the permeate flux and transmembrane pressure along with the separation efficiency of the membrane. It was shown that separation efficiencies above 99.5% could be obtained at all operating conditions up to the critical flux. It was observed that the concentration of oil in all collected permeate samples using the oil-water system was below 0.2 wt% when operating at a flux below the critical flux. Studies to date have been limited to the characterization of low concentrated emulsions below 15 vol.%. The average oil droplet size in highly concentrated emulsions was measured as 3200 nm employing direct light scattering (DLS) measurement methods. It was observed that the estimated cake layer thickness of 20 to 80 mm was larger than external diameter of the membrane tube i.e. 6 mm based on a large particle size. Settling of the concentrated emulsion permitted the detection of a smaller particle size distribution (30-100 nm) within the larger particles averaging 3200 nm. It was identified that DLS methods could not efficiently give the droplet size distribution of the oil in the emulsion since large particles interfered with the detection of smaller particles. The content of the smaller particles represented 1% of the total weight of oil at 30°C and 5% at 70°C. This was too low to be detected using DLS measurements but was sufficient to affect ultrafiltration. In order to study the critical flux in the presence of transesterification reaction and the effect of cross flow velocity on separation, various oils were transesterified in another membrane reactor providing higher cross flow velocity. higher cross flow velocity provides better separation by reducing materials deposition on the surface of the membrane due to higher shearing. The oils tested were canola, corn, sunflower and unrefined soy oils (Free Fatty Acids (FFA< 1%)), and waste cooking oil (FFA= 9%). The quality of all biodiesel samples was studied in terms of glycerine, mono-glyceride, di-glyceride and tri-glyceride concentrations. The composition of all biodiesel samples were in the range required by ASTM D6751 and EN 14214 standards. A critical flux based on operating pressure in the reactor was reached for waste cooking and pre-treated corn oils. It was identified that the reaction residence time in the reactor was an extremely important design parameter affecting the operating pressure in the reactor. / Natural Sciences and Engineering Research Council of Canada (NSERC)

This dissertation has focused on studying the effect of four glycine derivatives on the solid state properties of mannitol, glycine, and sucrose when freeze dried into blended mixtures. The primary goal was to assess their value for use in the stabilisation of vaccines in the solid state, by examining key physical and chemical characteristics, which have been documented to be beneficial to the stabilisation of biopharmaceutical formulations. The novel excipients; dimethyl glycine, and trimethyl glycine, were shown to retard the crystallisation and increase the overall glass transition temperature, of mannitol, when freeze dried as evidenced by DSC and Powder X-ray diffraction. Mannitol’s glass transition temperature increased from 100C to 12.650C and 13.610C when mixed with methyl-glycine and dimethyl glycine respectively. The glycine derivatives did not show the same effect on sucrose which remained amorphous regardless of the concentration of the other excipient. The different behaviour with the sucrose system was thought to be due to relatively high glass transition temperature of sucrose. Conversely glycine remained highly crystalline due it’s relatively low glass transition temperature. The novel excipient formulations were also assessed for their effect on the aggregation of the adjuvant aluminium hydroxide when freeze dried by Dynamic Light Scattering (DLS).The formulations containing the glycine derivatives all caused a decrease in the aggregation size of the adjuvant from ~26 μm, to 185 nm in the presence of methyl glycine. The effects of lysozyme and viral antigen on the adjuvants were also examined showing that the addition of the virus did not affect the size of the aggregates formed, however lysozyme showed significant decreases in the aggregates formed. Examination of the freezing method were also made showing that faster freezing rates produced smaller aggregates of the adjuvant. When investigating the rate at which the excipients lost water during secondary drying there was evidence of the formation of hydrates of glycine, trimethyl glycine, and mannitol has shown that the glycine derivatives have attributes which would be beneficial in stabilising vaccines in the solid state when freeze dried. / Stabilitech Ltd. and the Engineering and Physical Sciences Research Council (EPSRC).

No description available.

Die vorliegende Arbeit befasst sich mit der Synthese und der Untersuchung von Struktur-Eigenschaftsbeziehungen neuartiger V-förmiger, formstabiler Mesogene zur Realisierung biaxial nematischer Mesophasen (Nb). Alle synthetisierten Verbindungen besitzen ein formtreues Oligo(phenylenethinylen)-Grundgerüst, an welches laterale Alkyloxyketten und verschiedene terminale Substituenten (z. B. -CN, O(CH2)nCOOEt, Pyridyle) angebunden wurden. Durch dieses spezielle Design erhält man ausschließlich nematische und keine höher geordneten flüssigkristallinen Phasen. Durch den Einsatz verschiedener zentraler heterozyklischer Kernbausteine konnten erfolgreich Öffnungswinkel zwischen 108.9° und 160° realisiert werden. Dabei zeigen Thiadiazolderivate stets enantiotrope Mesophasen, wobei im Hochtemperaturbereich eine uniaxiale Phase mit biaxialen Aggregaten vorliegt. Beim Abkühlen konnte bei etwa 50 °C mittels Polarisationsmikroskopie und dielektrischer Spektroskopie ein Übergang in die Nb-Phase nachgewiesen werden. Die erstmalige Beobachtung eines direkten Übergangs von der isotropen Phase in die Nb-Phase gelang durch den Einsatz von Benzo[1,2-b:4,3-b]dithiophen als Kernbaustein.