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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
71

Liquid Extraction Based Surface Sampling: Liquid Microjunction Surface Sampling Probes Coupled with Mass Spectrometry

Walworth, Matthew John 01 August 2011 (has links)
The direct sampling of analytes from surfaces under atmospheric conditions followed by mass spectrometric analysis is an ever expanding area of scientific research. Atmospheric pressure surface sampling and ionization techniques for mass spectrometry (MS) offer the ability to interrogate samples that could not be studied under vacuum conditions required of more traditional MS surface analysis techniques. The geometry and nature of materials or surfaces that can be analyzed has been greatly expanded as a result. This dissertation characterizes and shows applications of liquid microjunction surface sampling probe (LMJ-SSP) electrospray ionization systems. The presented work compares traditional analytical work flows with novel analytical workflows utilizing LMJ-SSP-MS technology. The increase of throughput and/or chemical information without the sacrifice of analytical figures of merit is shown and discussed. The readout of analytical surfaces; surfaces where analyte has ended up on a surface in a traditional work flow and not just placed there, constitutes the focus of what is presented in the preceding work. Finally the prospects for spatial liquid chromatography-mass spectrometry (LC-MS) as a powerful analytical technology „in wait‟ is discussed and supported by the presented data.
72

Synthesis, fractionation, characterisation and toxicity of naphthenic acids from complex mixtures

Jones, David January 2013 (has links)
Amongst the polar organic compounds occurring in unrefined and refined crude oils and the associated polluted production waters, complex mixtures of acids, known historically as naphthenic acids (NAs), have achieved prominence. This is particularly because NAs have been designated a toxicant class of concern in the oil sands process-affected water (OSPW) that has accumulated in vast quantities following exploitation of the oil sands of Northern Alberta, Canada in recent years. However, though there have been calls for NAs to be added to pollutant inventories, at the initiation of the current study, little knowledge existed of the exact composition of refined or unrefined NAs. The overall aim of the current study was therefore to identify individual NAs in refined (commercial) and unrefined (e.g. oil sands process-derived) complex mixtures of acids and then to assess the toxicity of any identified NAs. Individual NAs were tentatively identified by interpretation of the electron ionisation mass spectra of methyl ester derivatives, following comprehensive multidimensional gas chromatography-mass spectrometry (GCxGC-MS). Reference acids were then either purchased, or more commonly, where they were not commercially-available, synthesised, mainly by micro-hydrogenation methods, for co-chromatography and comparison of mass spectra of methyl esters with those of unknowns. The synthetic NAs, purified to >97% were then subjected to toxicological assessments using the Microtox™ assay. In all, 34 compounds were obtained pure enough for testing. Microtox results revealed that the toxicity endpoint (50% Inhibition Concentration, IC50) was between 0.004 and 0.7 mM. Exponential and other correlations were noted between carbon number and toxicity in several of the structural groups of acids assayed, which may be beneficial for predictions of toxicity of non-synthesised acids. Although n-hexanoic acid (IC50 0.7 mM) had the lowest toxicity, adamantane-type acids were the least toxic as a group overall. Conversely, the decahydronaphthalene (decalin)-type acids had the largest range of toxicities (IC50 0.004 to 0.3 mM) and the most toxic acid assayed was 3-decalin-1-yl-propanoic acid. According to USEPA guidelines many individual acids can be said to show low to medium toxicity. Since the acids in commercial and unrefined NAs occur in complex mixtures, an attempt was also made to assess mixture toxicity. Mixtures of individual structural groups of acids (e.g. acyclic isoprenoid acids, n-acids) and a mixture of all 34 acids were assessed. Apart from the adamantane sub-group of acids, all of the mixtures showed toxicities lower than the sum of the parts when calculated using equations for Concentration Addition and Model Deviation Ratios (simply the predicted IC50/Observed IC50). A hypothesis that achievement of a critical micelle concentration is required to produce toxicity was proposed to explain the lower than expected results. Some of the mass spectra of NA present in the commercial and unrefined mixtures were inconsistent with those of any of the alicyclic acids synthesised or purchased. These were hypothesised to be aromatic acids. Fractionation experiments of the NA mixtures using silver ion thin layer chromatography and solid phase extraction (Ag+TLC and Ag+SPE) were carried out in order to provide further evidence for aromatic acids. Ag+TLC allowed separation of a methylated NA mixture from OSPW into three distinct fractions; Ag+SPE resulted in eleven fractions, through the use of a wider range of solvents and differential solvent ratios. Analysis of the fractions by GC-MS revealed that each fraction was largely still made up of unresolved acids (as esters), although one or two fractions revealed some resolved acids. Use of averaged mass spectra and mass chromatography on each fraction revealed further resolved chromatographic peaks and associated interpretable mass spectra. Each of eight of the eleven sub-fractions were examined by GC-MS, in some cases by GCxGC-MS, and all by infrared spectroscopy, ultraviolet visible spectrophotometry and elemental analysis. A number of structures were proposed for the aromatic acids, including those with sulphur-containing moieties. It was noted that far from being minor components, aromatic acids comprised ca.25-40% of the OSPW acid extracts.
73

Coupling of electron spectroscopies for high resolution elemental depth distribution profiles in complex architectures of functional materials / Spectroscopies électroniques couplées pour l'analyse haute résolution d'agencements complexes de matériaux fonctionnels

Risterucci, Paul 23 April 2015 (has links)
Ce travail de thèse est focalisé sur la détermination, de manière non-destructive, d'interfaces profondément enterrées dans des empilements multi-couches utilisés dans les conditions de technologie réelles au travers d'une méthode innovante basée sur la photoémission avec utilisation de rayons-x de haute énergie (HAXPES) et l'analyse du fond continu inélastique. Au cours de cette thèse, une procédure numérique a été développée pour quantifier la correspondance entre la mesure du fond continu faite par HAXPES et la simulation du fond continu représentative d'une distribution en profondeur donnée. Cette méthode permet de trouver la distribution en profondeur d'un élément grâce à une procédure semi automatisée. Dans un premier temps cette méthode a été testée en étudiant une couche ultra fine de lanthane enterrée à une profondeur >50 nm dans un dispositif de grille métallique high-k. L'influence des paramètres utilisés lors de l'analyse y est étudiée et révèle l'importance principale d'un paramètre en particulier, la section efficace de diffusion inélastique. La combinaison de mesures HAXPES avec l'analyse du fond continu inélastique utilisant cette nouvelle méthode permet d'augmenter la profondeur de sonde jusqu'à un niveau sans précédent. Ainsi l'échantillon peut être sondé jusqu'à 65 nm sous la surface avec une haute sensibilité à une couche nanométrique. Dans un second temps, la méthode précédemment validée d'analyse de fond continu inélastique est combinée avec une étude haute résolution des niveaux de cœur dans un échantillon servant de source dans un transistor à haute mobilité. Les deux analyses sont complémentaires puisqu'elles permettent d'obtenir la distribution en profondeur des éléments ainsi que leur environnement chimique. Le résultat donne une description complète des diffusions élémentaires dans l'échantillon suivant les différentes conditions de recuit. / This thesis tackles the challenge of probing in a non-destructive way deeply buried interfaces in multilayer stacks used in technologically-relevant devices with an innovative photoemission method based on Hard X-ray PhotoElectron Spectroscopy (HAXPES) and inelastic background analysis. In this thesis, a numerical procedure has been implemented to quantify the matching between a HAXPES measured inelastic background and a simulated inelastic background that is representative of a given depth distribution of the chemical elements. The method allows retrieving depth distributions at large depths via a semi-automated procedure. First, this method has been tested by studying an ultra-thin layer of lanthanum buried at depth >50 nm in a high-k metal gate sample. The influence of the parameters involved in the analysis is studied unraveling the primary importance of the inelastic scattering cross section. The combination of HAXPES with inelastic background analysis using this novel method maximizes the probing depth to an unprecedented level, allowing to probe the sample up to 65 nm below the surface with a high sensitivity to a nm-thick layer. Second, the previously-checked inelastic background analysis is combined with that of high resolution core-level spectra in the case of the source part of a high electron mobility transistor. The two analyses are complementary as they allow retrieving the elemental depth distribution and the chemical state, respectively. The result gives a complete picture of the elemental intermixing within the sample when it is annealed at various temperatures. / Denne afhandling omhandler problemet med at probe dybt begravede grænseflader i multilags stacks, som bruges i teknologisk relevante devices, med en innovativ fotoemissions metode, der er baseret på Hard X-ray PhotoElectron Spectroscopy (HAXPES) og analyse af den uelastiske baggrund. I afhandlingen er en numerisk procedure blevet implementeret til at kvantificere forskellen mellem en HAXPES målt uelastisk baggrund og en modelleret baggrund, som svarer til en given dybdefordeling af atomerne. Metoden muliggør, med en halv-automatisk procedure, at bestemme dybdefordelingen i store dybder. Metoden er først blevet testet ved at studere et ultra-tyndt lag af lanthan, som er begravet i en dybde > 50 nm i en high-k-metal-gate prøve. Indflydelsen af parametrene der ingår i analysen er blevet studeret for at opklare den primære betydning af det anvendte uelastiske spredningstværsnit. Kombinationen af HAXPES med analyse af den uelastiske baggrund og brug af den nye numeriske metode giver en hidtil uset probe-dybde, som giver mulighed for at probe den atomare sammens ætning i op til 65 nm dybde under overfladen og med høj følsomhed af et kun nm tykt lag. Dernæst er den uelastiske baggrundsanalyse blevet kombineret med højopløst core-level spektroskopi for at studere de aktive dele i en høj-elektronmobilitets transistor. De to analyser er komplementære, idet de henholdsvis bestemmer den atomare fordeling og atomernes kemiske bindingstilstand. Resultatet giver et fuldstændigt billede af atomernes omfordeling i prøven når denne opvarmes til forskellige temperaturer.
74

Fonctionnalisation d'un fil métallique par croissance de films minces dans un magnétron cylindrique inversé / Functionalization of a metallic wire by growth of thin films in an inverted cylindrical magnetron

Le Coz, Thomas 15 February 2018 (has links)
Les travaux présentés dans ce manuscrit traitent de l’optimisation du procédé de dépôt de couches minces sur un fil d’acier inoxydable en mouvement. Deux magnétrons cylindriques inversés (ICM) sont utilisés pour étudier différents aspects de la pulvérisation cathodique. Dans un premier temps, un modèle analytique permettant l’évaluation des contributions thermiques à l’échauffement du substrat est confronté à des séries de mesures. Les résultats obtenus sont concluants mais souffrent de l’inhomogénéité du champ magnétique, lequel est à l’origine de pertes localisées d’électrons secondaires de haute énergie. Afin de limiter la contribution thermique des charges sur le substrat, des anodes auxiliaires, destinées à récupérer le flux d’énergie, sont ajoutées à chaque extrémité des magnétrons. Leur influence sur la distribution du plasma, sur la microstructure et sur la composition chimique des dépôts est alors discutée. Dans une seconde partie, l’étude des magnétrons lors de dépôts réactifs met en avant la nécessité d’homogénéiser le champ magnétique dans les cathodes. Une discussion est alors conduite sur l’influence du champ magnétique sur la distribution des vitesses de dépôt au sein des magnétrons et un modèle analytique, ayant pour but de reproduire les profils de dépôt, est développé sur la base des résultats obtenus. Une étude paramétrique (pression, distance cible – substrat, intensité du champ magnétique) est aussi réalisée afin de déterminer les conditions de dépôt optimales dans un ICM. Finalement, de la modélisation par éléments finis à l’aide d’un logiciel commercial vient clore le manuscrit. / The work presented in this manuscript deals with the optimization of the process of deposition of thin films on a moving stainless steel wire. Two inverted cylindrical magnetrons (ICMs) are used to study different aspects of sputtering. At first, an analytical model allowing the evaluation of the thermal contributions to the heating of the substrate is confronted with series of measurements. The results obtained are conclusive but suffer from the inhomogeneity of the magnetic field, which is responsible for the localized loss of high energy secondary electrons. In order to limit the thermal contribution of the charges on the substrate, auxiliary anodes designed to recover the energy flow, are added to each end of the magnetrons. Their influence on the plasma distribution, the microstructure and the chemical composition of the coatings is then discussed. In a second part, the study of reactive sputter deposition with ICMs highlights the need to homogenize the magnetic field in the cathodes. A discussion is then conducted on the influence of the magnetic field on the distribution of deposition rates within the magnetrons and an analytical model, aimed at reproducing the deposition profiles, is developed on the basis of the results obtained. A parametric study (pressure, target – substrate distance, magnetic field strength) is also performed to determine optimal deposition conditions in an ICM. Finally, finite element modeling using commercial software closes the manuscript.
75

Couches minces de langasite pour applications piézoélectriques : élaboration par chimie douce et caractérisation / Langasite thin layer for piezoelectric applications : soft chemistry elaboration and caracterisation

Mevel, Mehdi 10 December 2014 (has links)
L'objectif de cette thèse est l'élaboration de couche mince piézoélectrique sans plomb pour des applications mécatroniques. Le matériau piézoélectrique sélectionné est la langasite, La3Ga5SiO14, qui conserve ses propriétés à haute température (Tfus = 1470°C). L'élaboration par chimie douce permet une mise œuvre simple et économique. De nombreuses synthèses ont été réalisées variant précurseurs, ligands et solvants Des analyses thermogravimétriques et thermiques différentielles complétées par des caractérisations par spectroscopie infrarouge ont permis de comprendre les étapes de décompositions des précurseurs pour les différentes synthèses. Ainsi les précurseurs chlorures ne permettent pas la formation de langasite pure puisque restant dans la sphère de coordination du lanthane jusqu'à haute température. Nous avons retenu une synthèse à base de précurseurs nitrates permettant la formation d'une solution stable, nécessaire pour la réalisation de dépôts et conduisant à la formation de la langasite pure. Pour être piézoélectrique une couche mince doit être texturée dans une direction correspondant à une direction piézoélectrique du matériau. L'objectif de la thèse était au départ de déposer la langasite sur un substrat souple bitexturé de Ni95W5/LZO. Tous les essais de dépôts ont conduit à l'oxydation de ce substrat, même sous atmosphère inerte, d'autres substrats ont donc été étudiés. Les films obtenus ont essentiellement été caractérisés par diffraction des rayons X en mode tetha/2tetha, phi scan et figures de pôles. Des études par microscopie électronique à transmission ont également été menées. La morphologie des dépôts a été caractérisée par AFM. Les essais sur MgO (111) ou Si (100) ont conduit à la formation d'une couche mince de langasite polycristalline. Le dépôt de langasite sur MgO (100) possède une orientation préférentielle des plans (110) et (101). Des dispositifs SAW réalisés sur plusieurs couches n'ont pas permis de mettre en évidence des propriétés piézoélectriques. La dégradation de la langasite dans les films a ensuite été mise en évidence et peut expliquer ces résultats. Les dépôts de langasite sur spinelle MgAl2O4, présentent une texture fibrée des plans (002). Les perspectives de ces travaux concernent la mesure des coefficients piézoélectriques des dépôts sur spinelle ainsi que des essais de dépôt d'une couche métallique sur la surface des films afin de les protéger et éviter ainsi leur dégradation. / The objective of this PHD is the development of piezoelectric thin layers without lead element. The selected piezoelectric material is the langasite, La3Ga5SiO14, which keeps its piezoelectric properties at very high temperature (Tm = 1470°C). The chosen langasite synthesis is a soft chemistry way which is economical and easy to work. We have made many tests with different metal precursors, different solvents and ligands. Infrared spectroscopy, X-ray diffraction, differential thermal analysis and thermogravimetric analysis were done to study the decompositions steps. Thus, the synthesis with chlorides precursors lead to impure langasite due to chloride atoms which stay in the coordination sphere of lanthanum at high temperature. We selected a based nitrate synthesis which allows the formation of stable solution leading to pure langasite. To be piezoelectric, a thin layer must be a textured layer, and the orientation of the texture must be a piezoelectric direction. To depose langasite on flexible bitextured substrate of Ni95W5 / LZO was the first aim of this PHD. All tests led to the oxidation of this substrate. Further to these results other substrates were studied. The films were analyzed by X ray diffraction in (theta/2theta), phi scan and pole figures. The morphology of the layers was studied by AFM. Tests on MgO (111) or Si (100) led to the formation of polycrystalline langasite thin Layer. Deposition of langasite on MgO (100) led to two preferred orientation (110) and (101) . SAW electrodes were deposited on these layers but any piezoelectric properties were measured. Further degradation of films has been shown. Depositions on spinel MgAl2O4 , present a fibrous texture of the (002) planes . The prospects of this work concern the piezoelectric coefficients measurement of spinel deposit. Depositions tests of a metallic layer to protect the films langasite from degradation have to be made.
76

Inclusão de colesterol na membrana plasmática de espermatozoides caprinos / Inclusion of cholesterol to goat sperm membrane

Silveira, Camila Oliveira 22 February 2013 (has links)
Made available in DSpace on 2015-03-26T13:47:12Z (GMT). No. of bitstreams: 1 texto completo.pdf: 765049 bytes, checksum: dcb0cc188aa67726f24e856817503e00 (MD5) Previous issue date: 2013-02-22 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The aim of this study was to evaluate the fertilizing capacity, acrosomal integrity, and qualify and quantify by chromatographic techniques the incorporation of cholesterol to the sperm membrane by cyclodextrin in different diluents on cryopreservation of goat sperm. Four males, Saanen (2) and Parda Alpine (2) breeds were used. It was performed a completely randomized design, with each semen sample divided into the following treatments: TG - Tris-glycerol diluent; TGCCC - Cyclodextrin-cholesterol complex (CCC) + Tris-glycerol diluent; TG15CCC - CCC diluted in isosmotic solution (saline) to semen with 15 minutes of incubation before addition of the Tris-glycerol diluent; EE - egg yolk + ethylene glycol diluent; EECCC - CCC + egg yolk + ethylene glycol diluent; EE15CCC - CCC diluted in isosmotic solution (saline) to semen with 15 minutes of incubation before addition of the egg yolk + ethylene glycol diluent. Fresh semen, after its examination, was submitted to the cryopreservation process and stored in a cryogenic cylinder for 10 days. After thawing, the following analysis were performed: acrosomal integrity, sperm fertilizing capacity through perivitelline membrane of hen egg yolk binding test (MPEY) and analysis of sperm motility and vigor. Besides, techniques of gas and thin layer chromatography were conducted to evaluate the incorporation of cholesterol to the sperm membrane. Data were submitted to Lilliefors and Cochran and Bartlett tests to verify normality and homogeneity of variances, respectively. The characteristics that met the assumptions of these tests were submitted to ANOVA and means were compared by Duncan s test at 5% of probability. When data did not meet the assumptions of normality and homogeneity of variances, the means were compared by Kruskal-Wallis test. Pearson s correlation coefficient was calculated in all features.Addition of cyclodextrin-cholesterol complex did not increase binding of sperm to MPEY (P > 0.05). The EE15CCC treatment was superior to EECCC treatment in maintaining the acrosomal integrity but did not differ from control (EE; P > 0.05). In Tris-glycerol diluent, the values observed in the control treatment were higher (P < 0.05) than values of the other treatments (TGCCC and TG15CCC) in maintaining the acrosomal integrity. There was a negative correlation between the binding assay and acrosomal integrity (r = -0.25) and positive correlation between the binding assay and sperm motility (r = 0.20). The sperm motility and acrosomal integrity were negatively correlated (r = -0.26). In quantitative and qualitative evaluation of cholesterol by chromatographic techniques (gas and thin layer) there was no difference between the samples of semen in different treatments (P > 0.05). Both techniques showed no incorporation of cholesterol to spermatozoa. It was concluding that addition of cholesterol-cyclodextrin complex to the medium did not improve the physical aspects of goat semen, or the sperm binding capacity. Pre-incubation of semen with CCC for 15 minutes before addition of ethylene + egg yolk diluent (EE15CCC) did not enhance the integrity of the acrosome in relation to control (EE). The gas and thin layer chromatography showed, respectively, an efficient method for quantitatively and qualitatively determining the cholesterol present in the cryopreserved goat sperm. The concentration of 1 mg of cholesterol-cyclodextrin complex added to the goat semen was not effective for increasing the concentration of cholesterol in sperm. / O objetivo do presente estudo foi avaliar a capacidade fecundante, integridade acrossomal, além de qualificar e quantificar por técnicas cromatográficas a incorporação do colesterol à membrana plasmática do espermatozoide pela ciclodextrina em diferentes diluentes na criopreservação de espermatozoides caprinos. Foram utilizados quatro machos caprinos das raças Saanen (2) e Parda Alpina (2) seguindo um delineamento inteiramente casualizado, dividido nos seguintes tratamentos: TGcontrole negativo para o diluente a base de Tris-glicerol; TGCCC- Complexo ciclodextrina-colesterol (CCC) + diluente Tris glicerol; TG15CCC- CCC diluído em solução isosmótica ao sêmen (soro fisiológico) com 15 minutos de incubação antes da adição do diluente Tris glicerol; EE- controle negativo para o diluente a base de Gema de ovo + etilenoglicol; EECCC- CCC + diluente Gema de ovo + etilenoglicol; EE15CCC- CCC diluído em solução isosmótica ao sêmen (soro fisiológico) com 15 minutos de incubação antes da adição do diluente Gema de ovo + etilenoglicol. O sêmen fresco, após realização de sua análise física foi submetido ao processo de criopreservação e estocado em botijão de nitrogênio por 10 dias. Após o descongelamento realizou-se análise da integridade acrossomal, capacidade fecundante do espermatozoide por meio do teste de ligação à membrana perivitelina da gema do ovo de galinha (MPGV) e as análises de motilidade progressiva e vigor espermático. Além destes testes foi realizada a avaliação da incorporação do colesterol à membrana plasmática dos espermatozoides pelas técnicas de cromatografia gasosa e de camada delgada. Para verificação da normalidade e homogeneidade dos dados foi empregado, respectivamente, o teste de Lilliefors e Cochran e Bartlett. As características que atenderam as premissas destes testes foram submetidas à ANOVA e as médias foram comparadas pelo teste de Duncan com 5% de probabilidade de erro. Quando as distribuições não atenderam as premissas de normalidade e homogeneidade, as médias foram comparadas pelo teste de Kruskal-Wallis. Realizou-se a correlação simples de Pearson entre todas as características. A adição do complexo ciclodextrina-colesterol não aumentou a ligação dos espermatozoides a MPGV (P>0,05). O tratamento empregando o complexo ciclodextrina-colesterol (CCC) diluído em solução isosmótica ao sêmen com 15 minutos de incubação antes da adição do diluente a base gema de ovo + etilenoglicol (EE15CCC) foi superior aos valores médios do tratamento EECCC na manutenção da integridade acrossomal, porém não diferiu dos valores do tratamento controle para este diluente (EE; P >0,05). No diluente Tris-Glicerol, os valores observados no tratamento controle foi superior (P<0,05) aos valores médios dos demais tratamentos (TGCCC e TG15CCC) na manutenção da integridade acrossomal. Houve correlação negativa entre o teste de ligação e a integridade do acrossoma (r= -0,25) e positiva entre o teste de ligação e a motilidade espermática progressiva (r= 0,20). A motilidade espermática progressiva e a integridade do acrossoma apresentaram correlação negativa (r= -0,26). Na avaliação quantitativa e qualitativa do colesterol pelas técnicas cromatográficas (gasosa e camada delgada) não se verificou diferença entre as amostras do sêmen nos diferentes tratamentos (P>0,05). Ambas as técnicas demonstraram que não houve incorporação do colesterol aos espermatozoides. Conclui-se que o complexo ciclodextrina-colesterol no meio diluidor não melhorou os aspectos físicos do sêmen caprino pós-descongelamento e a capacidade de ligação à membrana perivitelina da gema do ovo de galinha. A pré-incubação do sêmen com o CCC por 15 minutos antes da adição do diluente a base de Etilenoglicol+ gema de ovo (EE15CCC) não proporcionou um aumento na integridade do acrossoma a ponto de diferir dos valores do tratamento controle (EE). A cromatografia gasosa e de camada delgada demonstraram, respectivamente, um eficiente método quantitativo e qualitativo para determinar o colesterol presente no espermatozoide caprino criopreservados. A concentração de 1 mg do complexo ciclodextrina-colesterol adicionada ao sêmen caprino não foi eficaz em aumentar a concentração de colesterol presente no espermatozoide.
77

Análise farmacognóstica de amostras de drogas vegetais psicoativas comercializadas em Diadema / Pharmacognostic analysis of samples of psychoactive herbal drugs marketed in Diadema

Thiago Macrini 02 February 2012 (has links)
As plantas medicinais são conhecidas há muitos séculos pelos homens, e ainda hoje são amplamente utilizadas no tratamento de enfermidades. A população acredita que é uma alternativa segura e de baixo custo em relação aos produtos farmacêuticos industrializados, e faz seu uso indiscriminado e sem acompanhamento médico. A automedicação e a falta de controle de qualidade das drogas vegetais (DVs) representam um sério risco à saúde de seus usuários. A diversidade de espécies conhecidas como plantas medicinais, e o uso de nomes populares regionais podem ocasionar erros de identificação taxonômica ou mesmo adulteração do produto. Outro fator que pode alterar a qualidade das DVs é a contaminação de origem química ou biológica, proveniente das diversas fases de seu preparo. Com o uso disseminado de DVs e fitoterápicos, cresceu a preocupação com os efeitos adversos e a interação com medicamentos convencionais. Esse panorama evidencia a interdisciplinaridade na área de plantas medicinais. Assim, o projeto, do qual derivou este de mestrado, é interdisciplinar, com a participação de pesquisadores da etnofarmacologia, microbiologia, farmacovigilância e farmacognosia. O objetivo específico desta dissertação de mestrado é avaliar a qualidade das DVs com possíveis ações psicoativas, adquiridas em barracas de rua na cidade de Diadema. As amostras selecionadas e adquiridas pelo grupo da etnofarmacologia foram confrontadas a monografias farmacopêicas, literatura especializada e/ou amostra autêntica, avaliando-se os caracteres macroscópicos, microscópicos, perfis cromatográficos e pureza das DVs. Cortes histológicos foram preparados conforme as técnicas usuais, cromatografias em camada delgada foram realizadas de acordo com literatura e fotografias documentam as análises. De um total de 35 lotes analisados, 88,6% confirmaram sua autenticidade, e apenas 57,1% estavam em conformidade com os valores máximos permitidos para materiais estranhos. Também ficou evidente a baixa qualidade de armazenamento do material e problemas com embalagens e rótulos, em total desacordo com a legislação vigente. Concluiu-se então que as DVs adquiridas demandam atenção e melhorias quanto à sua qualidade, fato que demonstra a necessidade de maior orientação e conscientização dos vendedores quanto aos cuidados para sua comercialização à população. / Medicinal plants have been known for centuries by humanity and are still widely used for the treatment of illnesses. People believe that it is a safer and low cost alternative in relation to manufactured pharmaceutical products and makes indiscriminate use of them, without medical supervision. Self-medication and the lack of quality control of herbal drugs (HDs) represent a serious health risk to users. The diversity of species known as medicinal plants and the use of popular regional names can cause errors in taxonomic identification or even product adulteration. Another factor that may alter the quality of HDs is contamination from biological or chemical origin, from various stages of their preparation. With the widespread use of herbal remedies and HDs, the concern about adverse effects and interactions with conventional medicines has increased. This scenario highlights the interdisciplinarity of the medicinal plants field. Thus, the project, which this master`s program was derived from, is interdisciplinary, involving researchers from ethnopharmacology, microbiology, pharmacovigilance and pharmacognosy. The specific aim of this master\'s project is to evaluate the quality of HDs with possible psychoactive action, acquired in street stalls in the city of Diadema. The samples selected and acquired by ethnopharmacology were confronted with pharmacopoeial monographs, literature and/or authentic samples and the macroscopic and microscopic characters, chromatographic profiles and purity of HDs were evaluated. Histological sections were prepared according to the usual techniques, thin layer chromatographys were performed according to the literature, and photographs document the analysis. From a total of 35 lots, 88.6% confirmed their authenticity, and only 57.1% were in compliance with the maximum limit for the amount of foreign material. The poor quality of material storage and problems with packaging and labels, in total disagreement with the law, was also made evident. We concluded that the acquired HDs require caution and improvement of their quality, which demonstrates the need for more guidance and awareness of vendors about the care involved in the commercialization of HDs to the population.
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Aminas biogenicas, aminas volateis, triptofano livre e ureia como indices quimicos de qualidade e frescor do pescado / Biogenic amines, volatile amines, free tryptophan and urea as chemical indices for quality and freshness evaluation of fish and sellfish

Lapa Guimarães, Judite 08 December 2005 (has links)
Orientadores: Pedro Eduardo de Felicio, Jana Pickova / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos / Made available in DSpace on 2018-08-04T20:04:37Z (GMT). No. of bitstreams: 1 LapaGuimaraes_Judite_D.pdf: 14813702 bytes, checksum: ceaf92aa9f32ece3f3b4c5ef620aa4ee (MD5) Previous issue date: 2005 / Resumo: Em função da alta perecibilidade do pescado, a avaliação do frescor e qualidade deste alimento deve ser precisa e baseada em métodos consolidados. Bases nitrogenadas voláteis (BNV), trimetilamina (TMA), aminas biogênicas, nucleotídeos, uréia e triptofano livre têm sido propostos como índices de frescor para pescado e podem ser efetivos ou não dependendo da espécie de pescado, microbiota contaminante e condições de armazenamento. A quantificação dos teores de aminas biogênicas é também importante devido ao seu potencial tóxico. Os objetivos deste estudo foram avaliar a utilidade das aminas biogênicas, BNV, TMA, triptofano livre e uréia como índices de qualidade e frescor em peixes e moluscos cefalópodes, desenvolver e avaliar sistemas de solventes para separação de aminas biogênicas por cromatografia de camada delgada e avaliar o efeito do tempo e temperatura de derivatização sobre a conversão das aminas biogênicas em seus derivados dansilados. Derivados dansilados de agmatina (AGM), putrescina (PUT), triptamina (TRY), cadaverina (CAD), histamina (HIS), espermidina (SPD), espermina (SPM), tiramina (TYR) e feniletilamina (PHE) foram separados utilizando-se o sistema de solventes clorofórmio: éter dietílico: trietilamina (6:4:1 - v/v) seguido de clorofórmio: trietilamina (6:1 ¿ v/v). A melhor condição para derivatização das aminas biogênicas com cloreto de dansila foi 1h a 40oC. AGM permaneceu no local de aplicação (RF=0,0), o que indica que a metodologia deve ser utilizada com cautela para a determinação desta amina. As percentagens de recuperação de TRY, SPM, SPD e TYR foram baixas, indicando que a metodologia para extração destas aminas deve ser aperfeiçoada. BNV e TMA foram consideradas índices de frescor inadequados para bacalhau (Gadus morhua) e hadoque (Melanogrammus aeglefinus). O padrão de produção mais acentuado a partir da segunda semana de armazenamento, caracterizou as aminas voláteis e as aminas biogênicas CAD e PUT como índices de deterioração para bacalhau e hadoque. Uréia se mostrou inadequada como índice de qualidade para as duas espécies de pescado estudadas. Modelos de regressão linear e quadrática indicaram um aumento progressivo dos teores de AGM em lula (Illex coindetii), de uréia em sépia (Sepia officinalis), e de BNV e triptofano livre nas duas espécies de cefalópodes desde o início do armazenamento. BNV e triptofano livre foram considerados bons índices de frescor para I. coindetii e S. officinalis, pois seus teores aumentaram significativamente (p<0,05) desde o início do armazenamento. AGM e uréia foram consideradas índices de deterioração para I. coindetii e S. officinalis, respectivamente. Os teores de TMA (% NNP) aumentaram significativamente (p<0,05) durante a primeira semana de armazenamento em I. coindetii o que sugere sua utilidade como índice de frescor para lula. Para S. officinalis TMA é mais adequada como índice de deterioração / Abstract: Fish and shellfish muscle is highly susceptible to spoilage during storage. Because quality quickly decreases during storage reliable chemical indices for quality and freshness evaluation are greatly needed. Total volatile bases-nitrogen (TVB-N), trimethylamine (TMA), biogenic amines, nucleotides, urea and free tryptophan have been suggested as freshness indices for fish and shellfish. Such indices are useful depending on the species, microbial flora and storage conditions. Biogenic amines levels are also cause of concernment due to their toxicological effects. The objectives of this study were to evaluate the usefulness of biogenic amines, TVB-N, TMA, free tryptophan and urea as freshness and quality indices for fish and cephalopods; to develop and evaluate solvent systems for biogenic amines separation by thin-layer chromatography; and to evaluate the effects of time and temperature of derivatisation on the conversion of biogenic amines to their dansyl derivatives. Dansyl derivatives of agmatine (AGM), putrescine (PUT), tryptamine (TRY), cadaverine (CAD), histamine (HIS), spermidine (SPD), spermine (SPM), tiramine (TYR) and phenylethylamine (PHE) were separated using the solvent system chloroform: diethyl ether: triethylamine (6:4:1 ¿ v/v), followed by chloroform: triethylamine (6:1 ¿ v/v). The best dansylation condition was 1h at 40oC. AGM remained at the start position, indicating the determination of AGM by this method should be considered with caution. The percentages of recovery of TRY, SPM, SPD and TYR were low, indicating that the extraction methodology must be improved. TVB-N and TMA were considered inappropriate as freshness indices for cod (Gadus morhua) and haddock (Melanogrammus aeglefinus). CAD and PUT showed the greatest increases during the storage, but their levels did not increase significantly (p<0.05) during the first week. Volatile amines and biogenic amines were characterized as spoilage indices for G. morhua and M. aeglefinus due to the intense increasing of their amounts from the second week of storage. Urea was not useful as a quality index for cod and haddock. Linear and quadratic models indicated progressive increasing of AGM levels in squid (Illex coindetii), urea in cuttlefish (Sepia officinalis) and also increasing of TVB-N and free tryptophan in both cephalopods, since the beginning of the storage. TVB-N and free tryptophan were considered good freshness indices for both cephalopod species, because their levels significantly increased (p<0.05) during the first week of storage. AGM and urea were useful as spoilage indices for I. coindetii and S. officinalis, respectively. It was observed a significant increase of TMA (% of NNP) during the first week of storage in I. coindetii indicating the TMA usefulness as freshness index for squid. For S. officinalis TMA was a good spoilage index / Doutorado / Doutor em Tecnologia de Alimentos
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Characterization of microbial growth in lignin-based residues and biodegradation of vanillin: : Optimizing factors for maximizing the extraction of a biodegradation compound of vanillin and investigating the potential for lipid accumulation.

Rosales, Oscar January 2017 (has links)
Vanillin (4-hydroxy-3methoxybenzaldehyde) is one of the most employed aromatic and flavoring additives in food and cosmetic industry. The industrial interest in vanillin could also apply to its biodegradation products. The microbial transformation of vanillin can open the possibility of new products with new areas of application for products related to vanillin. For example, vanillyl alcohol, vanillic acid and ferulic acid are currently used in the pharmaceutical or food industry. Some species reported to biodegrade vanillin into the related products vanillyl alcohol and vanillic acid, are: Brettanomyces anomalus and Saccharomyces cerevisiae. Moreover, certain microorganisms possess the ability to accumulate lipids when cultivated on different carbon sources, opening the possibility of microbial lipid production as another industrial application. The present investigation focuses on the optimization of extraction methods for vanillin biodegradation products, as well as identifying the isolates of a collection of microorganisms originating from the Faroe Islands that are amenable to being cultivated on a lignin-based media. Finally, the potential for microbial lipid accumulation was also studied. Two analytical methods, Thin-Layer Chromatography (TLC) and Gas Chromatography (GC) were employed for characterizing the biodegradation products obtained after 24 hours and 72 hours of culture in growth medium supplemented with 1 mM of vanillin. The results showed that after 24 hours of incubation, the model microorganism, strain FMYD002, had consumed some of the vanillin and transformed it into biodegradation products. TLC retention factors and GC chromatograms revealed that the main biodegradation product after 24 hours - when compared to a standard – is likely to be to vanillyl alcohol. Furthermore, vanillin and its biodegradation products were relatively temperature-stable based on a temperature test of supernatant from a 24-hour culture, however, when the 72-hour culture had been subjected to the highest temperature (60 °C) some spontaneous decomposition occurred. The biodegradation pattern of the 72-hour culture evidenced by TLC revealed two additional biodegradation products, one of which migrates in a similar fashion to vanillic acid. After 72 hours of incubation, the biodegradation product presumed to be vanillyl alcohol was no longer observed. Acidification tests showed that the best route for extraction of the product believed to be vanillyl alcohol is to adjust the extracted sample to a pH of 9. The cultivation test of the isolates in media prepared from different lignin-based residual products showed that 26 out of 60 initial strains grew regardless of the concentration of lignosulfonates and vanillin. Moreover, 17 strains grew in nitrogen-limited medium. Eight of the strains accumulated lipids. A preliminary categorization of isolates based on their colony morphology and capacity of growth on different substrates showed that to some extent, their morphology can predict the ability to grow on lignin- and vanillin-based media. This could help future scientists to easily screen for and select isolates with interesting activity for the ligno-cellulose industry.
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Contribution à la compréhension de la relation entre les paramètres de découpe et l'usure des outils / Contribution to the knowledge of the relation between the blanking parameters and tool wear

Jeannin, Thomas 08 November 2016 (has links)
Ces travaux de thèse proposent une analyse tribologique de l’opération de découpage sur presse. Une meilleure connaissance des mécanismes d’usure présents sur les poinçons de découpage est nécessaire pour permettre leur reproduction en laboratoire et ainsi tester de nouveaux matériaux d’outils, pour allonger leur durée de vie et augmenter la productivité des outillages. Dans un premier temps un tribomètre de type ouvert est développé afin de recréer les mécanismes d’usure par abrasion présents sur presse. Cette configuration ouverte est choisie car lors de la découpe, l’outil vient découper une pièce sur une surface neuve en continue. Les caractéristiques innovantes de ce tribomètre sont la possibilité d’installer directement des tôles identiques à celles découpées, et les distances de frottement qui peuvent approcher cinq kilomètres sur surface neuve. Une approche énergétique de l’usure est mise en place afin de comparer les résultats obtenus avec le tribomètre et les mesures sur presse. En effet, dans un second temps, des essais réels sur presse à découper avec un outil instrumenté sont conduits. La mesure de l’usure du poinçon par réplication et par activation superficielle sont les deux techniques « in-situ » mises en place lors des essais. Différentes configurations de découpe sont testées afin d’observer leur impact sur l’effort de découpage, l’aspect du bord découpé et l’usure du poinçon. L’usure du poinçon est trop faible dans l’essai de découpage pour être mesurée, mais les taux d’énergie dissipée dans le frottement peuvent être estimés. Dans un troisième temps une comparaison des énergies dissipées dans le frottement sur le tribomètre et sur presse montre d’importants écarts. Pour les expliquer, une simulation par éléments finis de l’opération de découpe est conduite. Une prédiction de l’usure est établie afin de montrer le potentiel de la méthode d’approche énergétique. Une analyse vibratoire de l’outil montre que la phase de fissuration de la tôle induit des oscillations parfois nombreuses du poinçon qui peuvent conduire à de l’usure par fatigue. Des essais d’usure par fatigue sont réalisés et montrent que suivant les nuances, le carbure de tungstène usiné par électroérosion à fil est moins résistant à l’écaillage. / This work proposes a tribological analysis of the blanking operation. A better knowledge of the wear mechanisms present on the cutting punches is necessary to allow their reproduction in the laboratory and thus to test new tools materials, to extend their life time and increase the productivity of the process. Firstly, an open-type tribometer is developed in order to recreate the abrasive wear mechanisms present on the press. The innovative characteristics of this tribometer are the possibility of directly installing sheets identical to cutting pieces, and the friction distances can approach five kilometers on new surface. An energy approach of the wear is conducted in order to compare the results obtained with the tribometer and measurements on the press. Secondly, real tests on a cutting press with an instrumented tool are carried out. The measurement of the wear of the punch by replication and thin layer activation are the two "in-situ" techniques put in place during the tests. Differents cutting configurations are tested in order to observe their impact on the cutting force, the appearance of the cut edge and the wear of the punch. The wear of the punch is too low in the cutting test to be measured, but the rates of energy dissipated in the friction can be estimated. Thirdly, a comparison of the dissipated energies of friction on the tribometer and on the press shows significant deviations. To explain them, a finite element simulation of the cutting operation is carried out. A prediction of wear is established to show the potential of the energetic approach. A vibratory analysis of the tool shows that the phase of cracking of the sheet induces sometimes numerous oscillations of the punch which can lead to wear by fatigue.

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