Yes / The density functional theory (DFT) based a unique model has been developed to predict the toxicity of ionic liquids using structural-feature based quantum chemical reactivity descriptors. Electrophilic indices (ω), the energy of highest occupied (EHOMO) and lowest unoccupied molecular orbital, (ELUMO) and energy gap (∆ E) were selected as the best toxicity descriptors of ILs via Pearson correlation and multiple linear regression analyses. The principle components analysis (PCA) demonstrated the distribution and inter-relation of descriptors of the model. A multiple linear regression (MLR) analysis on selected descriptors derived the model equation for toxicity prediction of ionic liquids. The model predicted toxicity values and mechanism are very consistent with observed toxicity. Cationic and side chains length effect are pronounced to the toxicity of ILs. The model will provide an economic screening method to predict the toxicity of a wide range of ionic liquids and their toxicity mechanism.

Intracellular membraneless organelles commonly arise by phase separation of biomolecules and are essential for cellular processes such as signaling, gene regulation, and reproduction. The abnormal behavior of these biomolecular condensates can lead to cancer and neurodegenerative diseases. Equilibrium thermodynamics can explain condensate properties like internal composition, selective segregation of molecules, and conditions for their assembly. However, cells are inherently out of equilibrium, and hence, many of the functionalities of intracellular condensates arise from coupling phase separation to active processes such as post-translational modifications. The mechanisms that cells employ to regulate the properties and associated functions of these out-of-equilibrium condensates are poorly understood. In vitro condensate models provide a bottom-up approach to gaining insights into these underlying active mechanisms that may be difficult to isolate in vivo. Complex coacervates formed by liquid-liquid phase separation of oppositely charged polyelectrolytes have been effectively used to emulate condensate properties because of their compatibility with biological processes and their responsiveness to environmental cues. In this dissertation, we aim to use in vitro coacervate systems to reproduce two main characteristics of native condensates - size regulation and stimuli-responsive internal structure. The two in vitro models described in this thesis utilize the effect of pH on coacervation to demonstrate control over coacervate size or morphology under non-equilibrium conditions. The experimental system consists of an anionic enzyme phase separating with a weak polycation, DEAE-dextran, to form micron-sized coacervate drops. The charges of both the polyelectrolytes are pH sensitive, which makes the electrostatic dominated coacervate assembly pH responsive. The anionic enzyme enriched in the coacervate catalyzes a reaction that changes the solution pH. In Chapter 2, we demonstrate that the anionic catalase enzyme causes a pH increase that dissolves the coacervates. In turn, the diffusion-limited consumption of substrate within large coacervate drops slows the enzymatic reaction, thereby completing the negative feedback loop. Using a combination of modeling and experiments, we show that drops larger than a critical size can potentially support a localized pH increase that leads to a size-dependent dissolution of coacervates. Although the presence of oxygen bubbles prevents the realization of size control in this system, our work provides a framework to achieve size regulation in active coacervates exhibiting negative feedback between coacervate assembly and enzymatic reactions. In Chapter 3, we harness the pH-sensitivity of coacervates to elucidate the mechanism of vacuole formation within glucose oxidase/DEAE-dextran coacervates in response to an external pH decrease. We show that the formation of hollow structures or vacuoles within the coacervates depends on the rate of pH decrease and droplet size. Our results reveal that vacuole development occurs under non-equilibrium conditions due to the diffusion-limited mobility of the polycation during a rapid pH decrease. This work serves as a platform to regulate condensate structure in response to changes in the local environment, laying the groundwork for designing synthetic cells with new capabilities.

Dans la première partie de ce travail, nous avons réalisé une étude préliminaire qui avait pour objectif d’étendre la série de complexes dinucléaires du fer [Fe2(CO)4(k2-P2N2)(μ-dithiolate)], comprenant des ligands diphosphine de type P2N2, à des complexes possédant un pont azadithiolate en vue d’étudier leur comportement en milieu acide et le rôle des différentes bases présentes dans la seconde sphère de coordination de ces composés. Les nouveaux complexes [Fe2(CO)6(k2-PPh2NR2)(μ-adtBn)] (R = Ph, Bn)) ont été obtenus par réaction entre le précurseur [Fe2(CO)6(μ-adtBn)] et les diphosphines cycliques PPh2NR2 (avec R = Ph, Bn). Ces complexes ont été caractérisés spectroscopiquement et structuralement. Nous avons aussi montré que les modes de coordination de l’anion (tcnsR)-, dans l’ensemble des complexes sont très différents et affectent, par conséquent, les réseaux cristallins d’une manière très importante. Ceci permet de dire que la longueur de la chaine alkyl de l’anion (tcnsR)- ne devrait pas être le seul paramètre structural affectant les températures de transition. Le type de groupement CN (N3, N4, N5 ou N6) intervenant dans la coordination devrait alors jouer un rôle important dans l’empilement des entités moléculaires dans le réseau cristallin et par conséquent, les interactions intermoléculaires qui sont à l’origine des caractéristiques de la transition de spin (température de transition, coopérativité,…), devraient être affectées par le mode de coordination de l’anion. Dans la seconde partie, nous avons réalisé la synthèse de notre dipolarophile à partir de la sérine et la préparation des dipôles (oxydes de nitriles). La condensation de ces derniers avec la dehydroalanine nous a permis l’obtention de nouveaux α-aminoesters isoxazoliniques. Ces nouveaux α-aminoesters isoxazoliniques ont été obtenus d’une façon très accessible, et dans des conditions douces par la réaction de cycloaddition 1,3-dipolaire. Les résultats obtenus confirment l’utilité de cette réaction comme étant une voie très efficace pour former des nouveaux isoxazolines avec des bons rendements. / In the first part of this work, we realised a preliminary study to extend the series of dinuclear iron complexes [ Fe2(CO)4 (k2-P2N2) (μ-dithiolate)], including diphosphine ligands type P2N2, to complexes having an azadithiolate bridge, in order to study their behavior in acid medium and the role of different bases present in the second coordination sphere of these compounds. The new complexes [Fe2 (CO) 6 (k2-PPh2NR2) (μ -adtBn)] (R = Ph, Bn)) were obtained by reaction between the precursor [Fe2(CO)6(μ -adtBn)] and the cyclic diphosphines PPh 2NR2 (with R = Ph, Bn). These complexes have been spectroscopically and structurally characterized. We have also showed that the anion coordination modes (tcnsR)– in all these complexes are very different and affect, consequently, crystal lattices in a very important way. This suggests that the length of the alkyl chain of the anion (tcnsR)- should not be the only structural parameter affecting transition temperatures. The type of CN grouping (N3, N4, N5 or N6) involved in the coordination should then play an important role in the stacking of molecular entities in the crystal lattice as a result the intermolecular interaction, which are the origin of the spin transition characteristics (transition temperature, cooperativeness, ...), should be affected by the coordination mode of the anion.In the second part, we have realized the synthesis of our dipolarophile from serine and the preparation of dipoles (nitrile oxides). Their condensations with dehydroalanine allowed us to newly obtain isoxazolinic α-aminoesters. These novel isoxazolinic α-aminoesters were obtained in an accessible method, and under mild conditions by the 1,3-dipolar cycloaddition reaction. The obtained results prove the usefulness of this reaction as being a very efficient way to form new isoxazolines with good yields.

Dusty plasmas are plasmas that contain solid particles of nano- or micrometer size. They are widespread in the cosmic environment and act as precursors in the formation of planets and stars. Such plasmas are also used in laboratories for the synthesis of nanocomposites, which have wide technological and medical applications. While a large scientific effort has been invested in the study and control of such plasmas, the initial growth mechanism of powders (i.e. before they reach several tens of nanometers) remains poorly known. This work contributes primarily to expand the fundamental knowledge in the field of dusty plasmas. Our goal is to understand the physical chemistry of high-frequency plasmas magnetically confined in chemically reactive gases. In addition, we aim by examining the kinetics of the precursors in the plasma to understand the mechanisms of nanoparticle formation in the volume and to control their characteristics in a magnetically confined low pressure Ar/C2H2 plasma. This contribution has a direct impact on science and plasma applications. Among the applications related directly to this research, we mention the synthesis of carbon-based nanocomposites for their integration in solar cells and biomaterials. By examining the plasma characteristics (plasma temperature and density, cation and anion density) and correlating them to those of the dust particles, we found that the magnetic field changes the process of the formation of these particles in the discharge at very low pressure. Specifically, it stimulates the nucleation of carbon nanoparticles through several channels, i.e. through the anions and cations. These nanoparticles include two different phases, an amorphous carbon layer and a porous core formed of grains aggregate. These grains are formed of graphite nanocrystals coated with an amorphous layer. Moreover, the radius of the dust particles increases with the magnetic field, which is related to the enhancement of their residence time in the plasma volume. / Les plasmas poudreux sont des plasmas qui contiennent des particules solides de taille nano- ou même micrométrique. Ils sont répandus dans l'environnement cosmique et jouent le rôle de précurseurs dans la formation des planètes et des étoiles. Ce type de plasma est également utilisé dans les laboratoires pour la synthèse des nanocomposites possédant de vastes applications dans le monde technologique et médical. Tandis qu’un grand effort scientifique a été investi dans l’étude et le contrôle de ce type de plasmas, les mécanismes initiaux de formation des poudres (i.e. avant qu’elles atteignent quelques dizaines de nanomètres) demeurent très peu connus. On sait toutefois que des réactions physico-chimiques sont à l’origine de précurseurs des poudres qui déclenchent la nucléation. Ce travail contribue en premier lieu à accroître les connaissances fondamentales dans le domaine des plasmas poudreux en général. Il s’agit en particulier de comprendre la physico-chimie des plasmas de haute fréquence de très basse pression soumis à un confinement magnétique dans des gaz chimiquement réactifs. Plus spécifiquement, l’objectif de ce travail est d’examiner la cinétique des précurseurs produits dans le plasma afin de comprendre les mécanismes de formation de nanoparticules en volume et le contrôle de leurs caractéristiques dans des mélanges d’Ar/C2H2 de très basse pression confinés magnétiquement. Cet apport a des retombées directes en science et applications des plasmas. Parmi les applications directement visées par cette recherche, notons la synthèse de nanomatériaux composites à base de carbone pour leur intégration dans les cellules solaires et les biomatériaux. En examinant les caractéristiques du plasma (température et densité du plasma, densité des cations et des anions) et en les corrélant à celles des particules de poudre, on constate que le champ magnétique modifie le processus de la formation des particules poudreuses dans la décharge à très basse pression. Plus précisément, il favorise la nucléation des nanoparticules de carbone à travers plusieurs voies impliquant les anions et les cations. Ces nanoparticules comprennent deux phases différentes, une couche de carbone amorphe et un noyau poreux formé d'un agrégat de grains eux-mêmes constitués de nanocristaux de graphite revêtus d'une couche amorphe. On constate que le rayon moyen des particules de poudre augmente avec le champ magnétique, ce qui est lié à l’amélioration de leur temps de résidence dans le volume du plasma.

Ce travail s'inscrit dans un cadre de recherches qui a pour objectif essentiel l'étude de l'effet des éléments réactifs sur l'oxydation à haute température (1373 K) d'alliages alumino-formaurs de type FeCrAl. Un alliage modèle, ne contenant pas d'éléments mineurs d'addition, a été utilisé pour cette étude. L'originalité de cette étude réside dans l'utilisation de la technique de revêtement sol-gel contenant le lanthane, le cérium ou l'yttrium. Les échantillons revêtus de sol-gel ont été recuits sous argon aux températures de 600, 800 et 1000°C. Les tests de cyclage thermiques montrent que les dépôts sol-gel de lanthane recuits à 1000°C et de cérium recuits à 600°C apportent une protection efficace à l'alliage. Le dépôt sol-gel d'yttrium n'a pas d'effet bénéfique sur le comportement à haute température même après recuit sous argon. L'analyse par la thermogravimétrie (ATG) montre que les recuits sous argon provoquent les prises de masse les plus importantes. Ceci est dû à l'augmentation de la diffusion anionique au stade initial de l'oxydation. L'utilisation de la DRX in situ nous permet de suivre l'évolution des réactions d'oxydation en identifiant les phases formées sur la surface des alliages. Après recuit ou exposition à 1100°C, le lanthane peut former des oxydes mixtes avec l'aluminium : LaAlO3 et LaAl11O18, le cérium ne forme aucun oxyde mixte avec les éléments d'alliages. L'yttrium est l'élément qui a l'affinité avec l'alumine la plus élevée. Pendant les recuits ou expositions à 1100°C, il peut former des oxydes mixtes avec l'aluminium : YAlO3 et Y3Al5O12. Les micro-observations montrent que la couche d'alumine développée sur l'alliage recouvert des dépôts sol-gel est généralement convolutée. Cette morphologie est le résultat de la formation des nouveaux oxydes dans la couche existante dû à un processus de diffusion mixte. Cette étude montre que les éléments réactifs lanthane, cérium et yttrium se localisent toujours à l'interface externe de la couche d'oxyde.

This thesis describes the synthesis and investigation of novel anion templated interlocked structures which incorporate the positively charged imidazolium and triazolium binding motifs for applications in anion recognition and sensing. Chapter One introduces the fields of anion supramolecular chemistry and mechanically interlocked structures, focusing on topics of particular relevance to this thesis, including anion recognition, anion sensing and the templated synthesis of interlocked architectures. Chapter Two details the incorporation of the imidazolium motif into the axle components of anion templated rotaxane hosts to achieve selective anion recognition by virtue of their interlocked binding cavities. The effects of exploiting imidazolium motifs with contrasting hydrogen bond donor arrangements and reducing the macrocycle size on the anion recognition properties of such systems were investigated using 1H NMR spectroscopy. Chapter Three reports the work undertaken to utilise fluorescent reporter groups as stoppers in the synthesis of anion sensing rotaxanes. Imidazolium- and triazolium based systems containing either luminescent ruthenium(II) bipyridyl complexes or the organic fluorophore anthracene were prepared and their anion sensing behaviours explored using fluorescence spectroscopy. Synthetic efforts to construct suitable photo-active rotaxanes are detailed. Chapter Four describes investigations of the novel naphthalimide triazolium motif both for use in interlocked molecular motion systems, and for fluorescence sensing applications. The preparation of a naphthalimide triazolium rotaxane, capable of selective, anion-induced, uni-directional shuttling which was investigated extensively using 1H NMR spectroscopy and optically signalled by perturbations in the UV/Vis spectrum, is detailed. Preliminary research studies into the potential to exploit this motif for surface based fluorescence sensing devices are also included. Chapter Five presents research into the utilisation of acyclic receptors displaying considerable binding induced conformational changes for fluorescence anion sensing. The recognition properties of a series of imidazolium-based receptors were studied, whilst the ability of a pyrene appended analogue to signal anion complexation via changes in excimer emission is reported. The control of interpenetrated assembly formation using anion-induced conformational changes within the threading component of a pseudorotaxane is also discussed. Chapter Six provides the experimental procedures and characterisation details for the compounds synthesised in this thesis. Chapter Seven is a summary of conclusions from Chapters Two, Three, Four and Five. Supplementary information relating to titration protocols, crystallographic data and surface studies is provided in the Appendices.

Neste trabalho investigou-se a influência da adição dos ânions cloreto, fluoreto e sulfato nas propriedades físico-químicas de nanopós de zircônia sintetizada pelo método Pechini. Análises de fluorescência de Raios-X, difração de Raios-X, espectroscopia no infravermelho, área de superfície específica, espectroscopia Raman, microscopia eletrônica de varredura, análise termogravimétrica, calorimetria diferencial por varredura, amplitude sônica eletrocinética e dilatometria foram realizadas para caracterizar os pós sintetizados. Os resultados obtidos mostraram que o tratamento térmico realizado para a obtenção dos pós retirou os ânions cloreto e fluoreto da composição química final da zircônia enquanto o ânion sulfato permaneceu. Mesmo sendo retirados os ânions cloreto e fluoreto influenciaram no processo de cristalização da zircônia modificando o tamanho de cristalito obtido. A permanência do ânion sulfato na composição química da zircônia se deve à maior energia de ligação com o cátion Zr 4+ assim, observou-se uma maior influência deste ânion no processo de cristalização. Isso permitiu a formação de cristalitos menores e a estabilização da fase tetragonal da zircônia. Em todos os casos, as análises mostraram que a influência dos ânions se deu por segregação dos mesmos na superfície da zircônia o que, principalmente no caso do ânion sulfato, tende a reduzir a energia da superfície da zircônia através do aumento da área de superfície específica. Verificou-se também que o ânion sulfato pode ser retirado da superfície da zircônia através da lavagem do pó em meio básico. Esse procedimento permitiu aumentar a área de superfície específica e tende a melhorar sua sinterabilidade. / In this study was investigated the influence of the addition of the chloride, fluoride and sulfate anions in the physico-chemical properties of zirconia nanopowders synthesized by the Pechini method. Analyses of X-ray fluorescence, X-ray diffraction, infrared spectroscopy, specific surface area, Raman spectroscopy, scanning electron microscopy, thermogravimetric analysis, differential scanning calorimetry, electrokinetic sonic amplitude and dilatometry were performed to characterize the synthesized powders. The results showed that the heat treatment performed to obtain the powders removed the chloride and fluoride anions from the final chemical composition of the zirconium whereas the sulfate anion anion remained. Despite the chloride and fluoride anions removal, they influenced the crystallization process of the zirconium, modifying the size of the crystallite obtained. The permanence of the sulfate anion in the chemical composition of the zirconia is due to the higher binding energy with the Zr 4 + cation, thus it was observed a greater influence of that anion in the crystallization process. That allowed the formation of smaller crystallites and the stabilization of the tetragonal phase of the zirconia. In all of the cases, the analyses showed that the influence of the anions occurred by their segregation on the surface of the zirconia which, particularly in the case of the sulfate anion, tends to reduce the surface energy of the zirconium by increasing the specific surface area. It was also found that the sulfate anion can be removed from the surface of the zirconia by washing the powder in a basic medium. That procedure increased the specific surface area and it tends to improve its sinterability.

Further in vivo functional studies were also performed. The SLC26A3 antibody was injected into the BALB/C mice seminiferous tubules using micropipette. The animals were sacrificed after three days, and CASA, daily sperm production (DSP) were used to evaluate sperm motility and spermatogenesis. The results showed that sperm motility was increased while there was no significant difference between DSP. Our results indicate that SLC26A3 on sperm does not play a dominant role in spermatogenesis, epididymal maturation and sperm motility. / In the first part of study, guinea pig sperm which were incubated in medium with various concentrations of Cl- resulted in varied percentages of capacitated sperm, in a concentration dependent manner. Depleting Cl-, even in the presence of HCO3 -, abolished sperm capacitation and vice versa, indicating the involvement of both anions in the process. Capacitation-associated HCO 3- dependent events, including cAMP production, protein tyrosine phosphorylation and pHi increase also depend on Cl - concentrations. Similar Cl- dependence was observed for sperm hyperactivated motility and sperm-egg fusion. The capacitation-associated events could also be significantly reduced by inhibitors or antibodies of CFTR and SLC26A3, with a more potent effect observed for niflumate, an inhibitor more selective for SLC26A3, over that of DIDS, an inhibitor more selective for SLC4 exchangers. The expression and localization of CFTR and SLC26A3 in guinea pig sperm were also demonstrated using immunostaining and Western blot analysis. Our results indicate that Cl- is required for the entry of HCO3- necessary for sperm capacitation, implicating the involvement of SLC26A3 in transporting HCO3 - with CFTR providing the recycling pathway for Cl- . / In the second part of study, GC-1 spg cell line that expresses SLC26A6 but not SLC26A3 was used as a negative control. The cells and sperm were pretreated with anion exchanger inhibitors and SLC26A3 antibody, and then membrane potential and intracellular calcium were measured. Our results showed that DIDS could inhibit the HCO3- deficiency induced depolarization of GC-1 spg cells as well as the depolarization induced by Cl- or HCO3- deficiency in sperm. Niflumate could inhibit the HCO3- induced [Ca 2+] i increase of the sperm but not GC-1 spg cells. SLC26A3 antibody had no effect on the GC-1 spg cells but it could block the depolarization caused by C--deficiency in sperm. / Our previous study has demonstrated the involvement of Cystic fibrosis transmembrane conductance regulator (CFTR) in transporting bicarbonate necessary for sperm capacitation. However, whether its involvement is direct or indirect remains unclear. The present study is design to investigate: (1) the possibility of a Cl-/HCO3- exchanger, solute carrier family 26, number 3 (SLC26A3), operating with CFTR during sperm capacitation, (2) the role and the underlying mechanisms of SLC26A3 in other sperm post-testicular processes and spermatogenesis. / Taken together, our results demonstrate the involvement of SLC26A3 in sperm function, particularly in transporting HCO3- necessary for sperm capacitation, which appears to be working with CFTR providing the recycling pathway for Cl- in parallel. The present results also provide an explanation to the observed subfertility in patients with SLC26A3 mutations. Further in vitro and in vivo studies also have shown that SLC26A3 does not play a predominant role in spermatogenesis but may affect other post-testicular maturation processes. / Chen, Wenying. / "November 2009." / Adviser: H.C. Chan. / Source: Dissertation Abstracts International, Volume: 72-01, Section: B, page: . / Thesis (Ph.D.)--Chinese University of Hong Kong, 2010. / Includes bibliographical references (leaves 101-109). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. Ann Arbor, MI : ProQuest Information and Learning Company, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstract also in Chinese.

Neste trabalho, foi desenvolvido equipamento portátil e procedimentos analíticos automáticos para determinação de cátions e anions em águas usadas para consumo humano e suprimento. Os procedimentos foram baseados no processo de multicomutação em fluxo e detecção fotométrica empregando fotômetro feito no laboratório. Os sistemas de fluxo foram construídos empregando válvulas solenóide, com interface independente de comutação acionadas por computador usando apenas um canal de bombeamento. O sistema proposto foi controlado por um computador rodando um software escrito em QuickBasic 4.5. Os dói fotômetros baseados em LED foram desenvolvidos usando como detectores de radiação foto-transistores e foto-diodos. Nos dois casos a fonte de radiação (LED) e o foto-detector foram acoplados a cela de fluxo obtendo assim, uma unidade compacta. O fotômetro foi projetado para usar um foto-transistor para determinações seqüenciais de nitrato, nitrito, ferro(II), ferro(III) em águas de rios.O fotômetro proposto usa um foto-diodo para determinação de cloreto por turbidimetria, fosfato e amonium por fotometria. A sistema de fluxo foi desenhado associando-se os processos de multicomutação e multisite garantindo redução de reagente e de efluente. O sistema sistema foi empregado para determinação de cloreto, fosfato e amônio em águas de rios. Os dois sistemas propostos apresentaram excelente performance incluindo boa precisão, freqüência analítica e baixo consumo de reagente. Além disso, o sistema baseado em multisite apresentou baixo volume de efluente gerado. As dimensões reduzidas de ambos os fotômetros e do modulo de analise em fluxo, permitiram a portabilidade, o que possibilita sua aplicação em condições de campo. / In this work it was developed a portable apparatus and automatic analytical procedures for the determination of cations and anions in waters used for human consumption and industrial provisioning. The procedures were based on the multicommutation process in flow analysis and detection was performed using a homemade photometer. The flow systems were designed employing a set of solenoid valves, which were assembled to work as independent commutation units, thus under computer control several solutions were handled using a single pumping channel. The proposed system was controlled by computer running a software wrote in QuickBasic 4.5. The two LED based photometers were developed using as light detection a phototransistor and a photodiode. In both cases, the radiation source (LED) and the photodector were coupled to the flow cell in order to obtain compact unit. The photometer designed using a phototransistor was employed for the sequential determination of nitrate, nitrite, iron(II) and iron(III) in river water. The photometer designed using a photodiode was employed in the system used for the determination of chloride by turbidimetry, phosphate and ammonium by photometry. The flow system was designed associating the multisite and multicommutation process intending reduction of the reagent consumption and waste generation. The useful of the system was proved performing the determination of chloride, ammonium and phosphate in river water. The two proposed systems presented very overall performance including precision and accuracy, analytical frequency and low reagent consumption. Furthermore, the system based on multisite approach presented a very low volume of waster generation. The reduced dimensions of both photometer and flow system module allow their portability, thus we can suggest that the proposed systems are reliable for work in field condition.

"December 2004" / Includes bibliographical references. / 2 v. (various pagings) : / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Thesis (D.Sc.)--University of Adelaide, School of Chemistry and Physics, Discipline of Chemistry, 2005