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Studies on the metabolism of ochratoxin A / Maria Aletta StanderStander, Maria Aletta January 1999 (has links)
The ochratoxins, metabolites of certain Aspergillus and Penicillium species are the first group
of mycotoxins discovered subsequent to the epoch-making discovery of the aflatoxins.
Ochratoxin A (OTA) is a very important mycotoxin owing to its frequent occurrence in
nature, its established role in Danish porcine nephropathy and in poultry mycotoxicoses and
its implicated role in Balkan endemic nephropathy and urinary system tumors among
population groups in North Africa. Chapters 2 and 3 highlight the importance of OTA and
the research currently being done on mycotoxins. These efforts are focused on the molecular
genetics of toxinogenic fungi; the mechanism of their action; species differences in
metabolism and pharmacokinetics; quantification of mycotoxins; risk assessments on the
exposure of man and animals to mycotoxins and regulations for the control of mycotoxin
contamination.
Methods developed to analyse OTA in different matrices by using reversed phase high
performance-liquid chromatography with fluorescence detection and tandem liquid
chromatography-mass spectrometry techniques are described in Chapter 10. Amino propyl
solid phase extraction columns were used for the first time in cleanup steps of ochratoxin
analysis. These techniques and methods were applied to the first survey on the levels of OTA
in coffee on the South African retail market (Chapter 5). The results suggest that the levels
of OT A in the coffee on the South African market are somewhat higher than the levels of
OTA in coffees on the European market.
The possibility to biologically produce different halogen-ochratoxins by supplementing the
growth medium of Aspergillus ochraceus with halogen salts was investigated. Bromoochratoxin
A was produced for the first time in this way. Supplementation of inoculated
wheat with potassium iodide and -fluoride resulted in the poisoning of the yeast and no iodoor
fluoro-ochratoxin B was produced. It was found that Aspergillus ochraceus produced OTA
in higher yields at elevated levels of potassium chloride. This finding has important
commercial applications in the production ofOTA (Chapter 4).
The ochratoxins are hydrolyzed in vivo by carboxypeptidase A. The hydrolysis of the
ochratoxins and analogues by carboxypeptidase A was measured in vitro in a structurefunction
relation study by employing mass spectrometric techniques. The kinetic data of the
ochratoxins were compared to the values of a number of synthesized structural analogues. It
was found that the halogen containing analogues had lower turnovers than their des-halo
analogues. There were no substantial differences in the kinetic data between the different
halogen containing analogues (Chapter 8).
The toxicokinetics of OTA in vervet monkeys were determined for the first time. The
clearance of OTA from the plasma suggested a two-compartment model and the elimination
half-life was determined to be 19-21 days. The half-life of OTA in humans was determined
by allometric calculations to be 46 days. We came to the conclusion that the long term
consumption of OT A contaminated foods will lead to potentially hazardous levels of the toxin
in the body (Chapter 9). This hypothesis can be substantiated by the incidence of OTA in the
blood of various population groups.
Possible ways to decontaminate OT A contaminated foods by degrading the compound
biologically with yeast; moulds or lipases to non-toxic compounds were investigated. Eight
moulds, 323 yeasts and 23 lipases were screened for ochratoxin degradation. A lipase from
Aspergillus niger is the first lipase that was proven to degrade OTA (Chapter 7). Four yeasts
were found to degrade OT A of which one, Trichosporon mucoides degraded OTA
substantially within 48 hours in a growing culture (Chapter 6). In addition to this first report
of yeasts which have the ability to degrade OTA, the fungi Cochliobolus sativus, Penicillium
islandicum and Metarhizium anispoliae also proved to degrade OT A. OT A was degraded in
all instances to the non-toxic ochratoxin a and the amino acid phenylalanine. / Thesis (PhD (Chemistry))--Potchefstroom University for Christian Higher Education, 2000
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Spectroscopic Analysis of Resin-Bound Peptides: Glutathione and FK-13Chan, Michael January 2014 (has links)
High-resolution magic angle spinning (HRMAS) NMR spectroscopy is used to study solid samples that are normally difficult to analyze due to broadening of peaks. Solid-phase peptide synthesis can bind peptides to an insoluble resin that can be analyzed with HRMAS NMR spectroscopy. A combination of HRMAS NMR and IRMPD spectroscopy, along with computational chemistry, was applied to analyze and evaluate the structure of resin-bound glutathione. Two-dimensional 1H-1H NMR experiments such as COSY, TOCSY, and ROESY were employed to assign and predict the structure of the resin-bound peptide. IRMPD results were used along with calculated protonated structures and spectra to evaluate the conformation of the peptide. The experimental spectrum was compared to the spectra and structures of the protonated species to hypothesize the most favoured structure. Molecular mechanics, molecular dynamics and DFT calculations were implemented to collect structures that best resembled the free and resin-bound glutathione peptide. The results from these methods were compared to determine the structure that is most probable for the glutathione peptide. A semi-folded conformation is the structure the resin-bound GSH most preferred as concluded from the NMR and DFT results. The IRMPD results were analyzed as separate from the resin-bound experiments and suggested protonated GSH had a folded conformation.
FK-13 was another peptide synthesized using the solid-phase peptide synthesis technique. The peptide was synthesized using a modified technique different from conventional methodology used in the past. The peptide was also analyzed using COSY, TOCSY, and ROESY to confirm that the synthesis was done correctly and hypothesize a structure. The low substitution of the peptide on the resin gave rise to minimal NOE interactions, but there was some evidence suggesting that the synthesis was successful and the peptide adopted a cyclic conformation. These initial results are useful for future analyses and conformational studies of this resin-bound peptide.
Further work needs to be done for both peptides to explore the structures in more detail. The explicit model of solvation should be used to explore the effect of solvent molecules on the conformation of the glutathione peptide as opposed to the implicit model that PCM provides. FK-13 could be synthesized better so that a higher substitution is achieved and better NMR results are obtained. The IRMPD results obtained by the McMahon group can then be compared to the NMR results and computational calculations can be performed to obtain realistic structures of the peptide.
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In vivo Solid Phase Microextraction for Brain Tissue AnalysisCudjoe, Erasmus January 2014 (has links)
New solid phase microextraction (SPME) method was developed for brain tissue bioanalysis on a liquid chromatography mass spectrometry platform.
To achieve set objectives, in vivo SPME desorption process was optimized for high throughput analysis through the development of a desorption device. Subsequently, new SPME coatings were developed for the extraction of polar neurotransmitters from biological matrices. In a targeted analysis, in vivo SPME was used to monitor of changes in the concentrations of endogenous compounds (multiple neurotransmitters) and exogenous drugs (carbamazepine and cimetidine) in the striatum of the rat brain extracellular fluid. For the first time, SPME was used for quantitative analysis of neurotransmitters and also study spacial distribution of other drugs in different regions of the brain extracellular fluid.
A new approach was developed for improved metabolites coverage in a global non-targeted metabolomics studies. The proposed in vivo method showed how complementary results can be obtained through the combination of microdialysis and SPME for simultaneous sampling of the brain extracellular fluid.
Finally, in a clinical application, SPME was used to monitor changes in the concentration of multiple neurotransmitters during deep brain stimulation of the pre-frontal cortex of the brain.
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Optimization of Solid Phase Microextraction for Determination of Disinfection By-products in WaterRiazi Kermani, Farhad January 2012 (has links)
A new technique for sample preparation and trace analysis of organic pollutants in water using mixed-phase thin film (MPTF) devices, combined with direct thermal desorption, cold trapping, gas chromatography-mass spectrometry (GC-MS) is presented for the first time. Two novel analytical devices, Carboxen/polydimethylsiloxane (CAR/PDMS) and polydimethylsiloxane/divinylbenzene (PDMS/DVB) TF samplers were fabricated using spin coating technique and glass wool fabric mesh as substrate. The samplers were easily tailored in size and shape by cutting tools. Good durability and flat-shape stability were observed during extractions and stirring in water. The latter characteristic obviates the need for an extra framed holder for rapid thin film microextraction (TFME) and makes the samplers more robust and user-friendly. The analytical performance of the MPTF devices was satisfactorily illustrated and compared with those of solid phase microextraction (SPME) fibers and PDMS thin film membrane using water samples spiked with seven N–nitrosamines (NAs), known as disinfection by-products (DBPs) in drinking water. Marked enhancement of extraction efficiencies (typically more than one order of magnitude) for the N-nitrosamines, including the hydrophilic ones, was obtained with the MPTF devices under generally pre-equilibrium conditions, compared to the SPME fibers and PDMS thin film membrane. The analytical results obtained in this study, including linearity, repeatability and detection levels at low ng/L for the tested compounds, indicate that the new thin film devices are promising for rapid sampling and sample preparation of trace levels of polar organic pollutants in water with sensitivities higher than SPME fibers and with a wide application range typical of mixed-phase coatings. The user-friendly format and robustness of the novel devices are also advantageous for on-site applications, which is the ultimate use of thin film samplers. Moreover, the thin film fabrication approach developed in this study offers the possibility of making other novel samplers with PDMS or different absorptive polymers such as polyacrylate (PA) and polyethylene glycol (PEG) as particle-free, or as particle-loaded thin films with a variety of adsorptive solid particles.
In another development in the course of this research, the performance and accuracy of the SPME fiber approach for sample preparation of selected DBPs were demonstrated and compared with the conventional liquid-liquid extraction (LLE) method by real drinking water samples analysis in collaboration with Health Canada. Four regulated trihalomethanes (THMs) and seven other DBPs known as priority by-products, including four haloacetonitriles, two haloketones and chloropicrin, were analyzed in real samples during two separate comparative studies. In each study, duplicate samples from several water treatment and distribution systems in Canada, collected and stabilized under the same protocol, were analyzed in parallel by two independent labs; in the University of Waterloo by an optimized headspace SPME-GC-MS and in Health Canada by a LLE-GC-ECD (electron capture detection) method equivalent to EPA 551.1. The values for the concentration of the analytes in the samples obtained by the two methods were in good agreement with each other in majority of the cases indicating that SPME affords the promise of a dependable sample preparation technique for rapid DBPs analysis. In particular, it was shown that the SPME fiber approach combined with GC-MS is a fast reliable alternative to the LLE-GC-ECD (EPA 551.1) method for analysis of the regulated THMs in the concentration ranges that are typical and relevant for drinking water samples.
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Antidepresantų amitriptilino ir venlafaksino mišinio išskyrimo iš kraujo plazmos optimalių sąlygų nustatymas / The determination of optimal conditions of isolation antidepressant amitriptyline and venlafaxine mixture from human plasmaGuokaitė, Gabrielė 18 June 2014 (has links)
Atlikta mokslinių literatūros šaltinių apžvalga. Tiriamųjų medžiagų identifikavimui ir kiekybinei analizei pritaikyta ir validuota efektyvioji skysčių chromatografija. Antidepresantų mišinys išskirtas iš kraujo plazmos kietos fazės ekstrakcijos metodu. KFE metodas optimizuotas keičiant eliuentą ir eliuento pH. Atliktas optimizacijos sąlygų palyginimas. Nustatyti 3 organiniai tirpikliai, kuriais efektyviausiai eliuuojamos sorbente sulaikytos tiriamosios medžiagos bei gauti statistiškai patikimi rezultatai (p>0,05) : 2 proc. etano rūgšties tirpalas 100 proc. metanolyje, 2 proc. etano rūgšties tirpalas 80 proc. metanolyje ir 2 proc. metano rūgšties tirpalas 100 proc. metanolyje. / In this thesis was performed research of scientific literature. Applied and validated high performance liquid chromatography for identification and quantification of target compounds. Antidepressant mixture extracted from blood plasma samples using LLE and SPE methods. SPE method was optimized by changing the elutor and its pH. Three organic solvents were determined, which best elute target compounds from sorbent and show statistical confidence (p>0,05): 2 proc. acetic acid in 100 proc. methanol solution, 2 proc. acetic acid in 80 proc. methanol solution and 2 proc. formic acid in 100 proc. methanol solution.
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Evaluating the Potential of Scaling due to Calcium Compounds in Hydrometallurgical ProcessesAzimi, Ghazal 04 August 2010 (has links)
A fundamental theoretical and experimental study on calcium sulphate scale formation in hydrometallurgical solutions containing various minerals was conducted. A new database for the Mixed Solvent Electrolyte (MSE) model of the OLI Systems® software was developed through fitting of existing literature data such as mean activity, heat capacity and solubility data in simple binary and ternary systems. Moreover, a number of experiments were conducted to investigate the chemistry of calcium sulphate hydrates in laterite pressure acid leach (PAL) solutions, containing Al2(SO4)3, MgSO4, NiSO4, H2SO4, and NaCl at 25–250ºC. The database developed, utilized by the MSE model, was shown to accurately predict the solubilities of all calcium sulphate hydrates (and hence, predict scaling potential) in various multicomponent hydrometallurgical solutions including neutralized zinc sulphate leach solutions, nickel sulphate–chloride solutions of the Voisey’s Bay plant, and laterite PAL solutions over a wide temperature range (25–250°C).
The stability regions of CaSO4 hydrates (gypsum, hemihydrate and anhydrite) depend on solution conditions, i.e., temperature, pH and concentration of ions present. The transformation between CaSO4 hydrates is one of the common causes of scale formation. A systematic study was carried out to investigate the effect of various parameters including temperature, acidity, seeding, and presence of sulphate/chloride salts on the transformation kinetics. Based on the results obtained, a mechanism for the gypsum–anhydrite transformation below 100°C was proposed.
A number of solutions for mitigating calcium sulphate scaling problems throughout the processing circuits were recommended: (1) operating autoclaves under slightly more acidic conditions (~0.3–0.5 M acid); (2) mixing recycled process solutions with seawater; and (3) mixing the recycling stream with carbonate compounds to reject calcium as calcium carbonate. Furthermore, aging process solutions, saturated with gypsum, with anhydrite seeds at moderate temperatures (~80°C) would decrease the calcium content, provided that the solution is slightly acidic.
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The fate and effects of sewage-derived pharmaceuticals in soilGielen, Gertruda Jacqueline Hariette Petronella January 2007 (has links)
The behaviour and impact of pharmaceuticals in the environment are still poorly understood. Pharmaceuticals are widely used and continually released into the environment causing increasing concerns about their impact on the environment beyond the intended human or veterinary use. Prescribed pharmaceuticals, typically, enter the environment either through excretion after human use or disposal of surplus medication. Sewage treatment plants do not completely remove pharmaceuticals and their metabolites and these have been detected in sewage treatment plant effluent and receiving waters. Land application of treated sewage effluent is widely practiced in New Zealand as an alternative to surface water discharge. Methods were developed to determine selected pharmaceuticals in environmental matrices such as sewage effluent, sewage solids, soil, and soil water. From these, pharmaceutical removal efficiencies were determined for three common sewage treatment processes; activated sludge, composting and land application of sewage effluent. The impacts of some common pharmaceuticals on soil microbial communities, together with the effect of prolonged exposure to sewage effluent on these communities were examined. Additionally, toxicity of sewage effluent, and toxicity mechanisms of specific pharmaceuticals were investigated using luminescent micro-organisms and lettuce seedlings. Pharmaceuticals were successfully detected in sewage effluent, sewage solids, compost, soil and soil water. The sewage treatment processes investigated, including land application, were able to remove or reduce pharmaceutical concentrations in sewage. In case of land application, volcanic soils were more efficient than sandy soils in pharmaceutical removal while irrigation rate and level of sewage pre-treatment also showed some effect on removal efficiency. Pharmaceuticals were not acutely toxic at environmental levels currently detected. Exposure of microbial communities to unnaturally high levels of pharmaceuticals did demonstrate that most pharmaceuticals were potentially able to induce stress in the microbial community although microbes were able to metabolise some of these pharmaceuticals. Twelve years of effluent irrigation resulted in microbial adaptation to aspirin, acetaminophen and tetracycline, indicating that these pharmaceuticals had an effect on microbial community. Presently, land application of treated sewage waste may be a suitable treatment for additional pharmaceutical removal provided that land application schemes are designed appropriately, and pharmaceutical accumulation in the soil is occasionally monitored. It would be prudent to recognise the potential risk that could be caused by chronic exposure to pharmaceuticals such that continued vigilance may lead to future indications of chronic effects at an early stage.
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Modélisation physique des procédés de fabrication des jonctions FDSOI pour le nœud 10 nm et en-deçà / Physical modelling of junction fabrication processes on FDSOI substrate for the 10 nm node and belowPayet, Anthony 18 May 2017 (has links)
La fabrication de jonctions implique de nombreux défis technologiques à mesure que les dispositifs se rétrécissent. Afin de mitiger les problèmes liés à la diminution agressive des dimensions des transistors, des substrats SOI ainsi que du silicium-germanium (SiGe) contraint ont été introduits dans les nœuds avancés. Ces nœuds nécessitent toutefois une jonction abrupte fortement activée, qui est réalisable avec la recristallisation en phase solide (SPER) et un faible budget thermique (500°C-5h).Dans ce manuscrit, la SPER du silicium, germanium et d’alliages SiGe est étudiée avec des méthodes atomistiques telles que le Monte Carlo Cinétique (KMC) et la dynamique moléculaire (MD). Le modèle KMC de SPER se base sur une équation d'Arrhenius et distingue des configurations locales à l'interface amorphe-cristal pour simuler la dépendance de la vitesse de SPER par rapport à l’orientation de substrat. Les simulations en dynamique moléculaire montrent que la vitesse de SPER sur les orientations de {111} est fortement dépendante de la taille de la cellule ainsi que de la température et du temps de recuit.Le modèle KMC est de plus étendu afin de considérer l'effet du bore pendant la SPER. Le bore peut en effet créer des complexes à la fois dans l’amorphe et le cristal et augmenter la vitesse de SPER. Cette augmentation est toutefois saturée lorsque le bore atteint de trop fortes concentrations. Un modèle de réaction de défauts traitant les complexes a été adjoint au modèle de SPER afin de correctement simuler la vitesse de SPER pour toutes les concentrations de bore. Dans les alliages (100)SiGe relaxés, l'énergie d'activation de la SPER possède un maximum à 40% de concentration de Ge.Le modèle KMC doit introduire en plus des liaisons Si-Si et Ge-Ge, la liaison Si-Ge pour simuler correctement la recristallisation des alliages. Le modèle est également utilisé pour émettre des hypothèses sur la vitesse de SPER sur d'autres orientations. Les simulations en dynamique moléculaire confirment également le comportement de l’énergie d'activation dans les alliages SiGe.Des expériences de diffractions par rayons-X suivant en temps réel la recristallisation d’alliages de SiGe contraints ont été réalisées avec un rayonnement synchrotron. La contrainte est perdue dans les alliages riches en Ge et la température de recuit semble avoir un rôle sur la relaxation. La rugosité de l'interface pourrait être le lien entre la relaxation de la contrainte et la température, du fait que des simulations en dynamique moléculaires révèlent l’influence de la température de recuit sur la rugosité de l'interface et que les défauts relaxant la contrainte ont été associés à une interface rugueuse.En résumé, le SPER et ses diverses dépendances ont été étudiées dans ce manuscrit par des approches atomistiques. Les conclusions tirées améliorent la compréhension actuelle de la SPER, permettant ainsi une meilleure optimisation de la fabrication des jonctions. / The junction fabrication involve numerous technological challenges as the devices shrink. To alleviate issues brought by the aggressive device scaling, Fully Depleted SOI substrates as well as strained silicon-germanium (SiGe) have been introduced in advanced nodes. They however require a highly-activated abrupt junction achievable with solid phase epitaxial regrowth (SPER) and a low thermal budget (500$^circ$C-5h).In this manuscript, the SPER of silicon, germanium and SiGe alloys is investigated using Kinetic Monte Carlo (KMC) and Molecular Dynamics (MD) methods. The KMC model of SPER uses an Arrhenius equation and distinguishes local configurations at the amorphous-crystalline interface to simulate the SPER rate dependence on substrate orientations. In MD simulations, the SPER rate on {111} orientations is found to heavily depends on the cell size, anneal temperature and time.The KMC model is furthermore refined to consider the effect of boron during SPER. Boron is known to create complexes in both amorphous and crystalline phases and increase the SPER rate. This increase however saturates at high boron concentrations. A defect reaction model handling the complexes has been conjoined to the SPER model to correctly simulate the SPER rate behaviour for all boron concentrations.In relaxed (100)SiGe alloys, the SPER activation energy possesses a maximum at 40% of Ge concentration. The KMC model introduces in addition to Si-Si and Ge-Ge bonds, the Si-Ge bond to correctly simulate alloy recrystallisation. The model is also used to hypothesise the rates on other orientations. MD simulations also confirm the activation energy behaviour in SiGe alloys.Finally, X-ray diffractions following in real-time the recrystallisation of strained SiGe alloys are performed with synchrotron radiations. The strain is lost in Ge-rich alloys. The strain relaxation can be related to the anneal temperature. The interface roughness could be the link between the strain relaxation and the temperature, as MD simulations exhibit an influence of the anneal temperature on the interface roughness and strain relaxing defects are associated to a rough interface.In summary, the SPER and its several dependencies are investigated in this manuscript with atomistic approaches. The drawn conclusions increase the current understanding of SPER, allowing a better optimisation of junction fabrication.
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Optimisation des jonctions de dispositifs (FDSOI, TriGate) fabriqués à faible température pour l’intégration 3D séquentielle / Low temperature devices (FDSOI, TriGate) junction optimization for 3D sequential integrationPasini, Luca 15 March 2016 (has links)
L’intégration 3D séquentielle représente une alternative potentielle à la réduction des dimensions afin de gagner encore en densité d’une génération à la suivante. Le principal défi concerne la fabrication du transistor de l’étage supérieur avec un faible budget thermique; ceci afin d’éviter la dégradation du niveau inférieur. L’étape de fabrication la plus critique pour la réalisation du niveau supérieur est l’activation des dopants. Celle-ci est généralement effectuée par recuit à une température supérieure à 1000 °C. Dans ce contexte, cette thèse propose des solutions pour activer les dopants à des températures inférieures à 600 °C par la technique dite de recristallisation en phase solide. Les conditions de dopage ont été optimisées pour améliorer le niveau d’activation et le temps de recuit tout en réduisant la température d’activation jusqu’à 450°C. Les avancées obtenues ont été implémentées sur des dispositifs avancés FDSOI et TriGate générant des dispositifs avec des performances inférieures aux références fabriquées à hautes températures (supérieures à 1000 °C). En utilisant des simulations TCAD et en les comparant aux mesures électriques, nous avons montré que la région la plus critique en termes d’activation se trouve sous les espaceurs de la grille. Nous montrons alors qu’une intégration dite « extension first » est le meilleur compromis pour obtenir de bonnes performances sur des dispositifs fabriqués à faible température. En effet, l’implantation des dopants avant l’épitaxie qui vise à surélever les sources et drains compense l’absence de diffusion à basse température. Ces résultats ont par la suite été étendus pour des dispositifs TriGate et FinFETs sur isolants. Pour la première fois, l’intégration « extension first » a été démontrée pour des N et PFETs d’une technologie 14 nm FDSOI avec des résultats prometteurs en termes de performances. Les résultats obtenus montrent notamment qu’il est possible d’amorphiser partiellement un film très mince avant d’effectuer une recroissance épitaxiale sur une couche dopée. Finalement, une implantation ionique à relativement haute température (jusqu’à 500 °C) a été étudiée afin de doper les accès sans amorphiser totalement le film mince, ce qui est critique dans le cas des dispositifs FDSOI et FinFET. Nous montrons que les niveaux d’activation après implantation sont trop faibles pour obtenir des bonnes performances et que l’implantation ionique « chaude » est prometteuse à condition d’être utilisée avec un autre mécanisme d’activation comme le recuit laser. / 3D sequential integration is a promising candidate for the scaling sustainability for technological nodes beyond 14 nm. The main challenge is the development of a low temperature process for the top transistor level that enables to avoid the degradation of the bottom transistor level. The most critical process step for the top transistor level fabrication is the dopant activation that is usually performed at temperature higher than 1000 °C. In the frame of this Ph.D. work, different solutions for the dopant activation optimization at low temperature (below 600 °C) are proposed and integrated in FDSOI and TriGate devices. The technique chosen for the dopant activation at low temperature is the solid phase epitaxial regrowth. First, doping conditions have been optimized in terms of activation level and process time for low temperatures (down to 450 °C) anneals. The obtained conditions have been implemented in FDSOI and TriGate devices leading to degraded electrical results compared to the high temperature process of reference (above 1000 °C). By means of TCAD simulation and electrical measurements comparison, the critical region of the transistor in terms of activation appears to be below the offset spacer. The extension first integration scheme is then shown to be the best candidate to obtain high performance low temperature devices. Indeed, by performing the doping implantation before the raised source and drain epitaxial growth, the absence of diffusion at low temperature can be compensated. This conclusion can be extrapolated for TriGate and FinFET on insulator devices. Extension first integration scheme has been demonstrated for the first time on N and PFETs in 14 nm FDSOI technology showing promising results in terms of performance. This demonstration evidences that the two challenges of this integration i.e. the partial amorphization of very thin films and the epitaxy regrowth on implanted access are feasible. Finally, heated implantation has been investigated as a solution to dope thin access regions without full amorphization, which is particularly critical for FDSOI and FinFET devices. The as-implanted activation levels are shown to be too low to obtain high performance devices and the heated implantation appears a promising candidate for low temperature devices if used in combination with an alternative activation mechanism.
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Isoflurano : desenvolvimento de um método analítico empregando microextração em fase sólida, incorporação em nanoemulsões e avaliação biológica das nanoemulsõesKrahn, Carolina Lopes January 2010 (has links)
O objetivo do presente trabalho foi desenvolver e validar um método analítico empregando microextração em fase sólida (SPME) para detecção e quantificação de isoflurano (ISO) na forma volátil e incluso em nanoemulsões intravenosas e, ainda, avaliar o efeito biológico destas. A detecção do ISO foi realizada através de cromatografia em fase gasosa com detector de ionização de chama (CG/DIC). As condições ideais para realização da pré-concentração e extração de ISO através da técnica de SPME foram temperatura ambiente, agitação constante, 30 min de extração e 2 min de dessorção no injetor do CG. O método desenvolvido foi validado avaliando os parâmetros de especificidade, linearidade, limites de detecção e quantificação, precisão, exatidão e robustez. As nanoemulsões contendo ISO foram desenvolvidas através da homogeneização à alta pressão, e apresentaram diâmetro médio, índice de polidispersão, potencial zeta e pH de 150 ± 0,78 nm, 0,08 ± 0,01, - 18 ± 2,4 mV e 6,03 ± 0,04, respectivamente. O pH foi ajustado para 7,4 (valor fisiológico). O teor de ISO nas formulações foi de 98,4 %. Não houve modificação das características físico-químicas das nanoemulsões após 30 dias de armazenamento a 8 ºC. Análises de espalhamento de luz múltiplo não demonstraram tendência a fenômenos de instabilidade física para as formulações. Os estudos do efeito anestésico das nanoemulsões intravenosas contendo ISO em cães evidenciaram uma redução significativa (p < 0,05) na dose comparada com a administração de ISO volátil. Não houve alterações no débito cardíaco, saturação de oxigênio na hemoglobina e nos biomarcadores das funções renal, hepática e muscular. Uma queda na pressão arterial dos cães foi observada em todos os tratamentos devido ao efeito hipotensor do ISO. Após administração das nanoemulsões contendo ISO e branca, observou-se taquipnéia, edema, eritema, e baixas concentrações de dióxido de carbono expiradas. Assim, a nanoemulsificação do ISO foi realizada com sucesso e a aplicação na anestesia geral intravenosa foi demonstrada. / The aims of this work were to develop and validate an analytical method using solidphase microextraction (SPME) to detect and quantify isoflurane (ISO) inhalation liquid and loaded in intravenous nanoemulsions, and also evaluate the biological effect of the formulations. ISO detection was made by gas chromatography with flame ionization detector (GC/FID). The ideal conditions setting for the pre concentration and extraction of ISO through SPME were environmental temperature, constant stirring, 30 min for extraction and 2 min for analyte desorption in the GC inlet port. The developed method was validated by means of specificity, linearity, detection and quantification limits, precision, accuracy and robustness. The ISOloaded nanoemulsions were formulated by high-pressure homogenization, and presented average diameter, polydispersity index, zeta potential and pH of 150 ± 0.78 nm, 0.08 ± 0.01, -18 ± 2.4 mV and 6.03 ± 0.04, respectively. The pH was adjusted to 7.4 (physiological value). The drug content on the formulations was 98.4 %. After 30 days of storage at 8 ºC no changes on nanoemulsion’s physicalchemical characteristics were observed. Multiple light scattering analysis did not demonstrate any physical destabilization phenomena for the formulations. The anesthetic effect study for the intravenous ISO-loaded nanoemulsions in dogs highlighted a significant reduction (p < 0.05) in dosage regimen when compared to the volatile ISO administration. There were no alterations on cardiac rate, oxygen hemoglobin saturation and on biomarkers of the renal, hepatic and muscle functionalities. A decrease in dog’s arterial blood pressure in all treatments due the hypotensive effect caused by ISO was observed. After the administration of the nanomulsions, ISO-loaded and unloaded, occurred tachypnea, edema, erythema and low end tidal concentrations of carbon dioxide. Taking all above into account, the method was considered easy on execution and suitable for laboratory routines, the ISO nanoemulsification was made successfully and its application on general anesthesia was demonstrated.
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