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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.
211

CONTRIBUTION CHIMIQUE A LA DEFINITION DE LA QUALITE : EXEMPLES DES SPIRITUEUX DE MYRTE (MYRTUS COMMUNIS L.) ET DE CEDRAT (CITRUS MEDICA L.) DE CORSE

Venturini, Nicolas 26 November 2012 (has links) (PDF)
Ce travail de thèse, développé en partenariat avec la Société Mavela et l'INRA de Corse, est axé autour de l'étude de deux plantes traditionnellement utilisées en Corse pour la préparation de spiritueux (liqueur et eau de vie) : le myrte commun (Myrtus communis L.) et le cédrat (Citrus medica L). Le mémoire de thèse se décline en deux parties principales : * Une partie fondamentale visant à établir une méthodologie d'analyse des spiritueux par chromatographie liquide couplée à la spectrométrie de masse, d'une part, et à définir et à réunir en un même corpus les règles de fragmentation des flavonoïdes, d'autre part. * Une partie appliquée dont l'objectif est de contribuer à la définition d'une qualité en termes de compositions volatile et phénolique. Ainsi, nous avons étudié la variabilité intraspécifique des baies de myrte récoltées en Corse et nous avons caractérisé différentes variétés de cédrats. La composition volatile des baies de myrte est dominée par le couple α-pinène/1,8-cinéole alors que la composition phénolique est riche en myricétine, myricétine-3-O-arabinoside, myricétine-3-O-galactoside et en épigallocatéchine. Cette " empreinte " chimique des baies est retrouvée dans les liqueurs et les eaux de vie correspondantes. En outre, les huiles essentielles ont une composition homogène pour l'ensemble des lieux d'échantillonnage. L'étude des caractéristiques morphologiques, génétiques, et chimiques de 24 variétés de cédrat a permis de différencier les variétés " ancestrales " et les variétés " hybrides ". Sur la base de l'analyse de la diversité morphologique et génétique, 13 variétés dont le cédrat de Corse (Citrus medica var. corsican) sont considérées comme des cédrats ancestraux alors que les 11 autres cultivars sont assimilés à des hybrides entre les cédratiers et d'autres espèces du genre Citrus. Au niveau de la composition chimique des huiles essentielles, les cédratiers ancestraux se distinguent des autres variétés par des chimiotypes à limonène/néral/géranial ou limonène/nérol/géraniol pour les feuilles et à limonène/ץ-terpinène ou limonène/néral/géranial pour les zestes. Au niveau des composés phénoliques, la distinction entre les cédrats ancestraux et hybrides n'a pas pu être mise en évidence. L'étude de la composition chimique des liqueurs élaborées à partir du cédrat de Corse a permis d'étudier l'influence de la maturité des fruits sur la qualité des spiritueux. Il apparait que la date de récolte n'a pas d'impact sur la composition en volatils. A contrario, les concentrations en acides phénoliques et en leurs dérivés diminuent fortement au cours du développement du fruit. En outre, nous avons défini la qualité de la liqueur en fonction des conditions expérimentales de sa préparation. Enfin, ce travail de doctorat est la première étape de la mise en place d'un programme de protection de l'origine géographique et botanique de ces productions identitaires.
212

Quantification of selected energy and redox markers in blood samples of chronic fatigue syndrome patients / Chantalle Moolman

Moolman, Chantalle January 2014 (has links)
Chronic, noncommunicable diseases such as chronic fatigue syndrome (also known as myalgic encephalomyelitis) are rapidly becoming a worldwide epidemic that profoundly affects public health and productivity. Chronic fatigue syndrome (CFS) is characterised by severe and debilitating fatigue and although its etiology is still unknown, recent studies have found considerable evidence that mitochondrial dysfunction and oxidative stress might be responsible for the underlying energy deficit in these patients. Adenine and pyridine nucleotides could be used as potential biomarkers for energy related disorders such as chronic fatigue syndrome because of their various functions in the energy and redox pathways. The first part of this study focussed on developing a liquid chromatography electrosprayionisation tandem mass spectrometry (LC-ESI-MS/MS) method for the quantification of these nucleotides in blood samples. Due to the instability of nucleotides in biological matrices it was also necessary to find a suitable extraction method that would be able to stop enzymatic activity via protein precipitation. Out of the four extraction methods investigated during this study, deproteinisation of whole blood samples with perchloric acid produced the highest nucleotide abundances. Although nucleotide standards were found to be stable in perchloric acid, nucleotide levels in blood samples were not stabilised by addition of perchloric acid. The second part of this study consisted of measuring the nucleotide levels in blood samples of controls and possible CFS patients in order to test the proof of concept of the new LCESI- MS/MS method. Despite changes in the nucleotide levels due to perchloric acid and problems with nucleotide instability, it was still possible to distinguish between the two groups based on the results obtained with the new LC-ESI-MS/MS method. The newly developed LC-ESI-MS/MS method proved to be reliable and adequate for nucleotide quantification in whole blood samples, thus the aim of this study was achieved. / MSc (Biochemistry), North-West University, Potchefstroom Campus, 2014
213

The biogeochemical source and role of soluble organic-Fe(III) complexes in continental margin sediments

Beckler, Jordon Scott 12 January 2015 (has links)
In the past couple of decades, the discovery that iron is a limiting nutrient in large regions of the ocean has spurred much research into characterizing the biogeochemical controls on iron cycling. While Fe(II) is soluble at circumneutral pH, it readily oxidizes to Fe(III) in the presence of oxygen. Fe(III) is highly insoluble at circumneutral pH, presenting organisms with a bioavailability paradox stemming from the physiological challenge of using a solid phase mineral for assimilatory or dissimilatory purposes. Interestingly, dissolved organic-Fe(III) complexes can be stable in seawater in the presence of oxygen, and an active flux of these complexes has recently been measured in estuarine sediments. Their sources and biogeochemical role, however, remain poorly understood. In this work, a suite of field and laboratory techniques were developed to quantify diagenetic processes involved in the remineralization of carbon in marine sediments in situ, investigate the role of these organic-Fe(III) complexes in sediment biogeochemistry, and characterize the composition of the ligands possibly involved in the solubilization of Fe(III) in marine sediments. The first-of-its-kind in situ electrochemical analyzer and HPLC was used to better constrain diagenetic processes that may lead to the formation of dissolved organic-Fe(III) complexes in the Altamaha estuary and Carolina slope. An intensive study of the Satilla River estuary reveals that dissimilatory iron-reduction contributes to the formation of sedimentary organic-Fe(III) complexes, which are demonstrated to serve as an electron acceptor in subsequent incubations with a model iron-reducing microorganism. Similar observations in deep-sea slope and abyssal plain sediments fed by the Mississippi and Congo Rivers suggest that dissimilatory iron reduction may represent an important component of carbon remineralization in river-dominated ocean margin sediments that may be currently underestimated globally. To confirm that these organic-Fe(III) complexes are produced during microbial iron reduction, novel separation schemes were developed to extract and identify Fe(III)-binding ligands from sediment pore waters. Preliminary results reveal the presence of a few select low-molecular weight compounds in all pore waters extracted, suggesting they might be endogenous ligands secreted by iron-reducing bacteria to non-reductively dissolve Fe(III) minerals prior to reduction.
214

Contribution de la fonction achats dans le processus d'innovation des industries agro-alimentaires / Analysis of the contribution of purchasing department into the innovation process : the case of the food industries

Viale, Laurence 01 June 2018 (has links)
Dans un contexte où l'injonction d’innover atteint son paroxysme, les différentes fonctions de l’entreprise sont à la recherche de processus susceptibles de renforcer leur capacité d’innovation. Notre recherche a pour objectif d’apporter un éclairage sur l’implication et la contribution de la fonction Achats dans le processus d’innovation des entreprises Agro-Alimentaires en construisant, d’une part, une typologie des acheteurs et en identifiant, d’autre part, certains facteurs organisationnels déterminants du succès de l'implication de cette fonction. Sur la base de nos résultats, l’implication réussie de la fonction Achats dans le processus d’innovation n’est pas l’affaire d’une performance particulière des facteurs inter-organisationnels mais plutôt le fruit d’une performance équilibrée sur un ensemble de composantes comme l’alignement des services et organisations en interne et externe, les compétences métacognitives des acheteurs, l’implication dans l’idéation, ainsi que l’attractivité interne et externe. / At the heart of the company's strategy for a long time, and compounded by globalisation, innovation is becoming increasingly collaborative, open to external organisations such as suppliers who can play a prominent role in innovations (product or service design, organisational or technical). As Purchasing is the internal/external interface, this function may have an impact on the companies' ability to innovate. Beyond the suppliers' contribution, and within the other departments, the purpose of this thesis is to help clarify and characterise innovation by the Purchasing department, a multi-faceted notion, as well as identify the endogenous and exogenous factors conducive to innovation.
215

Mapa de vulnerabilidade ambiental ao óleo e cartas SAO: trecho Praia Grande - Ilha Comprida, litoral paulista

Romero, Ágata Fernandes [UNESP] 22 May 2009 (has links) (PDF)
Made available in DSpace on 2014-06-11T19:32:17Z (GMT). No. of bitstreams: 0 Previous issue date: 2009-05-22Bitstream added on 2014-06-13T18:43:28Z : No. of bitstreams: 1 romero_af_dr_rcla.pdf: 17670184 bytes, checksum: 06d42107402ca20faf754bc99cbfe1ea (MD5) / Agência Nacional do Petróleo, Gás Natural e Biocombustíveis (ANP) / Este trabalho apresenta Mapas de Vulnerabilidade Ambiental ao Óleo simulando um vazamento de óleo no fundeadouro do Porto de Santos, próximo ao litoral de Praia Grande. Foram também elaboradas Cartas de Sensibilidade Ambiental ao Óleo (SAO) para o trecho do litoral paulista entre os municípios de Praia Grande e Cananéia. A metodologia utilizada para elaboração das Cartas SAO é baseada nas normas do Ministério do Meio Ambiente e para a elaboração dos Mapas de Vulnerabilidade foi utilizado o modelo SIMAP, desenvolvido pela empresa ASA, capaz de representar a mancha de óleo na superfície do mar, na linha de costa e na coluna d’água. A área apresenta trechos com intenso uso turístico, principalmente nos meses de verão e áreas com ambientes naturais preservados, com destaque à presença do sistema estuarino-lagunar de Cananéia-Iguape e Unidades de Conservação, que conferem à área grande importância ecológica. As Carta SAO foram geradas nas escalas tática (1:150.000) e operacional (1:50.000 e 1:25.000) e os Mapas de Vulnerabilidade foram gerados em escalas entre 1:100.000 e 1:750.000, de forma a abranger toda a área da mancha de óleo. Os resultados confirmam a necessidade de avançar na abordagem da sensibilidade da costa ao óleo, incorporando às cartas SAO informações sobre a probabilidade das áreas serem atingidas, estimativas do tempo de contato na costa e informações sobre a área da mancha que tem potencial tóxico à biota. / This paper shows the Environmental Vulnerability Maps a simulated oil spill in the anchorage of the Santos port, close to Praia Grande shore. ESI Maps for the São Paulo shore between the municipalities of Praia Grande and Cananéia were also built. The methodology used to build ESI Maps is based on the Ministry of the Environment rules and for the construction of the Vulnerability charts used the SIMAP model, developed by the ASA. This is capable of modeling the oil spill on the surface of the sea, in the coast line and in the water column. The whole area shows intense tourist use, especially during the summer and areas with preserved natural environments include the presence of the estuarine-lagoon system of Cananéia-Iguape and Conservation Units that give the area great ecological importance. ESI Maps were generated in the tatic range (1:150.000) and operational (1:50.000 and 1:25.000) and the vulnerability maps were generated using 1:100.000 and 1:750.000 scales, to cover the entire area of oil stain. The results confirm the sensitivity of the coast to oil, use of the information above has been incorporated in the ESI Maps to estimate shore contact lead time and of the oil spill and this toxicity potential on the environment.
216

Composição fenólica e atividade biológica in vitro e in vivo de frutas nativas brasileiras / Phenolic composition and biological activity in vitro and in vivo of Brazilian native fruits

Jackeline Cintra Soares 03 April 2018 (has links)
O Brasil possui condições climáticas adequadas para o desenvolvimento de um grande número de frutas nativas e essa biodiversidade tem se tornado um caminho promissor para a descoberta de novos compostos bioativos capazes de ser utilizados na formulação de alimentos funcionais e medicamentos. Os compostos fenólicos apresentam ações específicas, podendo atuar como antioxidantes e anti-inflamatórios, assim prevenindo doenças crônicas. Diante do exposto, o objetivo deste trabalho foi avaliar o potencial antioxidante, antiinflamatório e a composição fenólica de dez frutas nativas brasileiras ainda pouco conhecidas: araçá-boi (Eugenia stipitata), cambuití-cipó (Sagerectia elegans), murici vermelho (Bysonima arthropoda), murici guassú (Byrsonima lancifolia), morango silvestre (Rubus rosaefolius), cambuci (Campomanesia phaea), jaracatiá-mamão (Jacaratia spinosa), juquirioba (Solanum alterno-pinatum), fruta-do-sabiá (Acnistus arborescens) e cajá (Spondias mombin L.). Os extratos etanólicos (80% v/v) das polpas foram analisados inicialmente quanto à capacidade de sequestro dos radicais ABTS&#8729+ e ROO&#8729. A atividade anti-inflamatória foi avaliada in vivo por meio do modelo de migração de neutrófilos induzida por carragenina, enquanto que a composição fenólica foi realizada por técnicas cromatográficas (CLAE-DAD e CG-EM). As 5 frutas com as maiores atividades biológicas foram ainda analisadas quanto à capacidade de sequestro de O2 &#8729-, HOCl e NO&#8729, atividade anti-inflamatória por meio do ensaio de ativação do fator nuclear-&kappa;B (NF-&kappa;B) e composição fenólica por espectrometria de massas de alta resolução (LC-ESI-QTOF-MS). Em relação ao sequestro do radical ABTS&#8729+ o cambuití-cipó apresentou a maior atividade (749,88 &mu;mol TE.g-1) e para o ROO&#8729 o murici vermelho apresentou a maior atividade antioxidante (559,09 &mu;mol TE.g-1). Os animais tratados com araçá-boi, cambuití-cipó, murici vermelho, cajá e morango silvestre apresentaram reduções no influxo de neutrófilos comparados ao grupo carragenina (p < 0,05). Por meio das técnicas de CLAE-DAD e CG-EM foi possível identificar compostos fenólicos pertencentes a classe dos flavonoides (catequina, epicatequina, rutina, quercetina glicosilada, kaempeferol glicosilado, quercetina, procianidina B1 e procianidina B2), sub-classe do ácido hidroxibenzóico (ácido gálico) e sub-classe dos ácidos hidrocinâmicos (ácido cumárico, ácido ferúlico e caféico). O araçá-boi, cambuití-cipó, murici vermelho, morango silvestre e cajá foram as cinco frutas que apresentaram as maiores atividades antioxidantes e/ou anti-inflamatórias, cujo perfil fenólico por LC-ESI-QTOF-MS indicou a presença de 18 compostos no araçá-boi, 32 no cambuitícipó, 26 no murici vermelho e 20 e 11 compostos no morango silvestre e cajá, respectivamente. Vários dos compostos fenólicos identificados foram encontrados pela primeira vez nessas espécies. O cambuiti-cipó e murici vermelho se destacaram em relação ao sequestro de HOCl (EC50 4,99 e 4,41 &mu;g mL-1, respectivamente) e o cambuití-cipó foi o mais ativo para desativar o radical O2 &#8729- (EC50 68,33 &mu;g mL-1) e NO&#8729 (EC50 0,78 &mu;g mL-1). Já os extratos de murici-vermelho, cambuití-cipó e morango silvestre inibiram significativamente a ativação do NF-&kappa;B. Portanto, as frutas nativas brasileiras são fontes de substâncias antioxidantes e anti-inflamatórias, bem como de uma grande diversidade de compostos fenólicos, os quais podem propiciar importantes benefícios para a saúde humana. / Brazil has favorable climatic conditions for the development of a large number of native fruits and this biodiversity has become a promising path towards the discovery of new bioactive compounds capable of being used in the formulation of functional foods and medicines. Phenolic compounds show specific action mechanisms, being able to act as antioxidants and anti-inflammatories, thus preventing chronic diseases. However, few Brazilian native fruits are well known and consumed by the population, undermining the investigation of chemical composition as well as the identification/quantification of bioactive compounds. In light of this, the objective of this work was to evaluate the antioxidant and anti-inflammatory potentials as well as the phenolic composition of ten underexploited Brazilian native fruits, namely: araçá-boi (Eugenia stipitata), cambuití-cipó (Sagerectia elegans), murici vermelho (Bysonima arthropoda), murici guassu (Byrsonima lancifolia), morango silvestre (Rubus rosaefolius), cambuci (Campomanesia phaea), jaracatiá-mamão (Jacaratia spinosa), juquirioba (Solanum alterno-pinatum), fruto-do-sabiá (Acnistus arborescens) and cajá (Spondias mombin L.). Pulps ethanolic extracts (80%, v/v) were initially analyzed regarding scavenging capacity of the ABTS&#8729+ and ROO&#8729 radicals. Antiinflammatory activity was evaluated in vivo using the carrageenan-induced neutrophil migration model, while phenolic composition was determined by chromatographic techniques (HPLC-PAD and GC-MS). The five fruits with the highest biological activities were analyzed for O2&#8729-, HOCl and NO&#8729 radicals scavenging capacities, for in vitro anti-inflammatory activity by nuclear factor-&kappa;B (NF-&kappa;B) activation, and for phenolic composition by High Resolution Mass Spectrometry (LC-ESI-QTOF-MS). In relation to ABTS&#8729+ radical scavenging cambuiticipó showed the highest activity (749.88 &mu;mol TE.g-1), while for ROO&#8729 scavenging, murici vermelho had the highest antioxidant activity (559.09 &mu;mol TE.g-1). The animals treated with araçá-boi, cambuití-cipó, murici vermelho, cajá and morango silvestre reported decreases in neutrophils influx compared to carrageenan group (p <0.05). It was possible to identify by HPLC-DAD and GC-MS techniques phenolic compounds belonging to the class of flavonoids (catechin, epicatechin, rutin, glycosylated quercetin, glycosylated kaempeferol, quercetin, procyanidin B1 and procyanidin B2), subclass of hydroxybenzoic acid (gallic acid) and subclass of hydrocinnamic acids (coumaric, ferulic and caffeic acids). Araçá-boi, cambuitícipó, murici vermelho, morango silvestre and cajá were the five fruits with the highest antioxidant and / or anti-inflammatory activities. The phenolic profile analysis by LC-ESIQTOF- MS pointed the presence of 18 compounds in araçá-boi, 32 in cambuití-cipó, 26 in murici vermelho, 20 in morango silvestre and 11 in cajá. Several of the identified phenolic compounds were found for the first time in these fruit species. Cambuiti-cipó and murici vermelho stood out in relation to HOCl scavenging (EC50 4.99 and 4.41 &mu;g.mL-1, respectively) and cambuití-cipó was the most active to deactivate both O2 &#8729- radical (EC50 68.33 &mu;g.mL-1) as NO&#8729 (EC 500.78 &mu;g.mL-1). Murici vermelho, cambuití-cipó and morango silvestre extracts significantly inhibited the activation of NF- &kappa;B.Therefore, Brazilian native fruits are sources of antioxidant and anti-inflammatory substances, as well as a great diversity of phenolic compounds, which can provide important benefits for human health.
217

Real-time mass spectrometric analysis of catalytic reaction mechanisms

Yunker, Lars Peter Erasmus 01 May 2017 (has links)
Mass spectrometry was used to study two disparate transformations: in an applied project, the supposed degradation of perfluorooctanesulfonate (PFOS); and in a fundamental study, the Suzuki-Miyaura (SM) reaction was investigated in detail. The first investigation revealed that published methods to degrade PFOS were ineffectual, with apparent decreases being associated with adsorption onto available surfaces. In the Suzuki-Miyaura reaction, a dynamic series of equilibria were observed, and there is no direct evidence of a single pathway. Instead, there appear to be two mechanisms which are active in different conditions (one fluoride, one aqueous). Studies were initiated into the related SM polycondensation reaction and the hydrolysis of aryltrifluoroborates, the former indicating a step-growth mechanism, and the latter indicating a dynamic series of equilibria which are very sensitive to experimental conditions. Processing and interpretation of mass spectrometric data was a significant part of all of these projects, so a python framework was developed to assist in these tasks and its features are also documented herein. / Graduate / 0488 / 0486 / larsy@uvic.ca
218

Analyse des cyanotoxines dans différents organismes aquatiques et habitats de la réserve écologique de la Rivière-aux-Brochets

Skafi, Mourad 04 1900 (has links)
La diversité et la distribution des cyanobactéries dans les écosystèmes aquatiques conduisent à des effets nuisibles dans l’eau par la production d’une variété de toxines cyanobactériennes qui présentent des risques pour la faune et la santé humaine. Différentes techniques analytiques émergentes ont été développées pour détecter et quantifier les toxines cyanobactériennes dans l'environnement. Dans ce mémoire nous avons examiné la présence de cyanotoxines multi-classes, dont 12 microcystines, les anatoxines, la cylindrospermopsine (CYN), les anabaenopeptines (AP-A, AP-B) et la cyanopeptoline-A dans les eaux de surface et les poissons sauvages. L'échantillonnage a été conduit pendant l’été 2018, dans l'écosystème fluvial de la réserve écologique de la Rivière aux Brochets (QC, Canada) près de la Baie Missisquoi (Lac Champlain). La méthode analytique employée combine la chromatographie liquide ultra haute performance et une ionisation par électronébuliseur (UHPLC-ESI) avec l’usage d’un spectromètre de masse triple quadripôle. Sur les 18 cyanotoxines ciblées, 14 ont été détectées dans des échantillons d'eau de surface impactés par la floraison ; les toxines ont culminé au début de la mi-septembre avec les concentrations les plus élevées de MC-LR (3,8 μg L-1) et MC-RR (2,9 μg L-1). Parmi les 71 poissons prélevés sur le terrain (10 espèces au total), 38% avaient des détections positives d'au moins une cyanotoxine. Dans les échantillons positifs, les plages de concentration dans le muscle du poisson étaient les suivantes : la somme des microcystines ΣMC (0,16-9,2 μg kg-1), la CYN (46-75 μg kg-1), et les anabaénopeptines AP-A (1,1-5,4 μg kg-1) et AP-B (0,01 à 5,0 μg kg-1). Dans l'ensemble, 17% des échantillons de poisson étaient positifs pour AP-A ou AP-B. A notre connaissance, ceci constitue le premier signalement de bioaccumulation d'anabaénopeptines dans la faune. La somme maximale des concentractions des microcystines ΣMC dans les poissons était 1,15 fois plus élevées que la recommandation de l'apport quotidien (8 μg kg-1 de tissu-1) de l'Organisation mondiale de la santé (OMS) pour les adultes et équivalaient presque à la valeur dérivée pour les jeunes enfants 9.3 μg kg-1. La concentration de CYN était également environ 3 fois plus élevée que la limite dérivée des valeurs recommandées pour la santé humaine. / The diversity and widespread distribution of cyanobacteria in aquatic ecosystems lead to harmful effects in water through the production of a variety of cyanobacterial toxins, which pose a great danger to fauna and human health. Different emerging analytical techniques have been developed to detect and quantify cyanobacterial toxins in the environment. In this thesis we examined the presence of multi-class cyanotoxins, including 12 microcystins, anatoxins, cylindrospermopsin (CYN), anabaenopeptins (AP-A, AP-B) and cyanopeptolin-A in surface water and wild fish. Sampling was conducted during the 2018 summer season in the fluvial ecosystem of the Pike River ecological reserve (QC, Canada) near Missisquoi Bay, Lake Champlain. This study was carried out using an analytical method combining ultra-high-performance liquid chromatography and ionization by electrospray (UHPLC-ESI) with the use of a triple quadrupole mass spectrometer. Of the 18 cyanotoxins targeted, 14 were detected in surface water samples impacted by the bloom; toxins peaked in early mid-September with the highest concentrations of MC-LR (3.8 μg L-1) and MC-RR (2.9 μg L-1). Among the 71 fish sampled in the field from 10 species, 38% had positive detections of at least one cyanotoxin. In positive samples, the concentration ranges in fish muscle were as follows: the sum of microcystins ΣMC (0.16-9.2 μg kg-1), CYN (46-75 μg kg-1), AP -A (1.1-5.4 μg kg-1) and AP-B (0.01 to 5.0 μg kg-1). Overall, 17% of the fish samples were positive for AP-A or AP-B; to our knowledge, this is the first report of accumulation of anabaenopeptins in wildlife. The maximum sum ΣMC of microcystin concentrations in fish was 1.15 times higher than the recommendation of the World Health Organization (WHO) Daily Intake (8 μg kg-1 tissue-1) for adults and was almost equivalent to the derived value for young children 9.3 μg kg-1. The concentration of CYN was also approximately 3 times higher than the limit derived from the recommended human health values.
219

Aufbau und Funktionalisierung von Carbosiloxandendrimeren

Lühmann, Bettina 19 December 2002 (has links)
In der vorliegenden Arbeit wird die Synthese von Carbosiloxandendrimeren der dritten Generation durch repetitive Alkoholyse-Hydrosilylierungs-cyclen auf dem divergenten Syntheseweg beschrieben. Im Mittelpunkt der Arbeit stand jedoch die Funktionalisierung dieser Dendrimere mit einer Vielzahl metallorganischer (Ferrocenyl-, Übergangsmetallcarbonyl-verbindungen) bzw. organischer (stickstoffhaltige Ligandsysteme) Einheiten. Zudem wird die Darstellung amphiphiler und bifunktionaler Carbosiloxandendrimere vorgestellt. Die neu synthetisierten Verbindungen wurden analytisch umfassend charakterisiert, wobei die 29Si-{1H}-NMR-Spektroskopie sowie die Massenspektrometrie einen besonderen Stellenwert einnehmen.
220

Synthese und Charakterisierung peripher funktionalisierter Carbosiloxan- und Carbosilandendrimere

Buschbeck, Roy 02 February 2005 (has links)
In der vorliegenden Arbeit wird die Synthese und die Charakterisierung von Carbosiloxandendrimeren der 1. – 3. Generation, welche periphere Me2SiH, MeSiH2 bzw. SiH3 Gruppen besitzen, vorgestellt. Ausgehend von diesen Verbindungen konnte am Beispiel eines mit einer Dimethylvinylsilyl-Einheit funktionalisierten Titanocendichlorides gezeigt werden, dass sich durch die Hydrosilylierungsreaktion metallorganische Bausteine an SiH-funktionalisierte Carbosiloxandendrimere anbinden lassen. Einen weiteren Schwerpunkt dieser Arbeit bildeten Carbosilandendrimere. Eine neue Variante der Darstellung dieser Moleküle durch die konvergente Synthesemethode mit Hilfe von kettenverlängernden, 1 zu 2 bzw. 1 zu 3 verzweigten Bausteinen konnte partiell erfolgreich durchgeführt werden. Die Anbindung von cyclischen (12-Krone-4, 15-Krone-5, 18-Krone-6, Sila-8-Krone-3, Sila-11-Krone-4) und acyclischen (Triethylenglycolmonomethylether) Polyethern an dendritische Carbosilane der 1. und 2. Generation wird ebenfalls beschrieben. Hierzu wurden Carbosilandendrimere mit peripheren SiH-Einheiten durch Hydrosilylierung mit den entsprechenden allyl- bzw. vinylfunktionalisierten Ethern zur Reaktion gebracht. Die auf diesem Weg erhaltenen Dendrimere mit endständigen cyclischen bzw. linearen Polyethern wurden mit Alkalimetallionen (Li+, Na+, K+) umgesetzt und die entstandenen Komplexe massenspektrometrisch untersucht.

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