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The Global ETD Search service is a free service for researchers
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Showing 11 to 13 of 13 (0.042 seconds)Spelling suggestions: "subject:"evans blue"" "subject:"svans blue""
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Avaliação de corantes para a detecção da viabilidade do fitoplâncton marinho / Staining evaluation for detection of marine phytoplankton viabilityIzadora De La Volpe Mattiello 22 May 2014 (has links)
O fitoplâncton é sensível às perturbações ambientais e identificar a viabilidade destes organismos é importante para o monitoramento aquático. O termo viabilidade tem sido usado neste contexto para determinar basicamente se o organismo está vivo ou morto. O uso de corantes vitais e mortais tem sido uma das técnicas aplicadas neste tipo de análise, mas ainda não se conhece a potencialidade de alguns corantes que se apliquem a espécies de fitoplâncton. Neste trabalho, foram utilizadas espécies de diferentes grupos taxonômicos mantidas em cultivo, as quais foram submetidas a uma série de corantes vitais e mortais com o objetivo de detectar a viabilidade do fitoplâcton marinho. Dentre os corantes testados, o vermelho neutro, azul de Evans e o fluorescente CMFDA tiveram os melhores resultados (observado x esperado) em testes com diferentes porcentagens de células vivas e mortas. A combinação entre o corante vital vermelho neutro e o mortal azul de Evans não foi efetiva para análise simultânea. Alexandrium tamiyavanichii foi a espécie que teve menor afinidade com os corantes. Também foram comparados diferentes métodos de observação e registro de células coradas e não coradas, provando que é possível substituir a observação direta da microscopia pela filmagem no microscópio ou pela FlowCAM. A vantagem do uso destes métodos é que além de serem mais rápidos, é possível salvar as imagens capturadas e não é necessário fazer a análise instantaneamente. O método da filmagem é vantajoso, pois é fácil de ser desenvolvido em qualquer laboratório. / Phytoplankton cells are sensitive to environmental perturbations and, therefore, identifying their viability is important for aquatic monitoring. The term viability has been used in this context to determine whether an organism is alive or dead. The use of vital and mortal stains to detect phytoplankton viability is a promising approach. In this study we investigated the efficiency of several vital and mortal dyes in detecting marine phytoplankton viability. Best results were achieved with neutral red, Evans blue and the fluorescent stain in tests with different percentages of live and dead cells. The combination of neutral red and Evans blue (vital and a mortal stains, respectively) was not effective in simultaneous analysis. Alexandrium tamiyavanichii had low affinity for any given stain. Different observational methods were compared, suggesting that direct microscopic counts can be replaced by image acquisition methods using either a microscope-mounted camera or a FlowCAM. Such imaging methods are fast, allow image archiving, and image processing can be performed on a later stage, which is useful when several experiments need to be run in a short period of time.
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The Effects of Cold and Freezing Temperatures on The Blood Brain Barrier and Aquaporin 1, 4, and 9 Expression in Cope's Gray Treefrog (Hyla Chrysoscelis)Felemban, Dalal Nouruldeen January 2016 (has links)
No description available.
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Ausgewählte Eigenschaften des Sporopollenins der KieferBohne, Guido 27 February 2007 (has links)
Gegenstand der Arbeit sind Zusammenhänge zwischen physikochemischen Eigenschaften und Funktionen der Exine bei Ausbreitung, Bestäubung und Befruchtung. Dabei bewährte sich der Einsatz der 3-kammrigen Sporopolleninkapseln (Zentralkapsel und Sacci) in der Permeationschromatographie. Sowohl kinetisch bedingte chromatographische Dispersion kleiner Moleküle als auch Konzentrationsänderungen von Zuckern und Dextranmolekülen im Medium wurden zur Bestimmung von Permeabilitätskoeffizienten der Nexine genutzt. Die Wasserabsorptionskapazität von Exinefragmenten und die hydraulische Leitfähigkeit der Nexine wurden anhand von Konzentrationsänderungen ausgeschlossener Dextranmoleküle ermittelt. Das Tectum der saccalen Sexine ist eine Mikrofiltermembran mit scharfer Trenngrenze im Submikrometerbereich; daher werden an den Sacci nur Hydrokolloide mit Stokes''schen Radius über 100 nm (z.B. aus nativem Dextran) ausgeschlossen. Die Nexine ist eine nicht-ideale Umkehrosmose-Membran, die in Zucker- und Salzlösungen hohe Reflexionskoeffizienten zeigt; zusätzlich besitzt sie wenige große Poren, die den Austausch von Zuckern und selbst kleinen Polymermolekülen ermöglichen. Die hydraulische Leitfähigkeit der Nexine liegt im Größenbereich derjenigen von Plasmamembranen (0,39-0,48 µm s-1 MPa-1); die Ergebnisse zeigen, dass die Exine weder die Nährstoffaufnahme des Sporoplasten aus der lokulären Flüssigkeit noch dessen rasche Rehydratation in der Mikropyle behindert. Die Einfaltungen der distalen Nexine (oberhalb der Sacci) und die Omega-Faltung der Exine zwischen den Sacci (Leptom) bieten beim Quellvorgang Schutz vor zu schneller Flächenausdehnung der Plasmamembran. Der Corpus kann mit konzentrierten Elektrolytlösungen beladen werden. Beim anschließenden osmotischen Schwellen in Wasser reißt die Exine, und der Sporoplast wird mit anhaftender Intine ausgeschleudert. Wasser und andere polare Flüssigkeiten adhärieren stärker als hydrophobe Flüssigkeiten an Sporopollenin. Die Sporopolleninmatrix weist eine hohe Feststoffdichte auf, ist wenig quellfähig (0,18 mL g-1 TM) und deformationsstabil. Dies ermöglicht die Pulverbildung beim Trocknen. / Subject of this thesis are relationships between physicochemical properties and functions of the exine concerning propagation, pollination and fecundation. Here the application of the 3-chambered sporopollenin-microcapsules (central capsule and sacci) in permeation chromatography proved of value. Both the kinetically dependent dispersion of small molecules and changes in concentration of sugars and dextran molecules in the medium were analysed to determine permeability coefficients of the nexine. The water absorption capacity of exine fragments and the hydraulic conductance of the nexine were calculated by means of changes in concentrations of excluded dextran molecules. The tectum of the saccal sexine is a microfiltration membrane with a sharp cut off in the submicrometer range; thus hydrocolloids with Stokes´radii over 100 nm (e.g. from native dextran) are excluded from the sacci. The nexine is a non-ideal reverse osmosis membrane having high reflexion coefficients in sugar and salt solutions; in addition few large pores allow the exchange of sugars and even of small polymers. The hydraulic conductance of the nexine is in the range typically for plasmamembranes (0.39-0.48 µm s-1 MPa-1); the results indicate that the exine does neither obstruct the uptake of nutrients by the sporoplast from the locular fluid nor hinder the rapid rehydration in the micropyle. When rehydrating, the distal foldings of the nexine (above the sacci) and the omega-like folding of the exine between the sacci (leptom), provide protection for the plasmamembrane when its surface area has to increase too rapidly. The corpus can be loaded with a concentrated electrolyte solution. When subsequently transferred into water the exine rupture and the sporoplast along with the intact intine is ejected. Water and other polar liquids adhere stronger to sporopollenin than hydrophobic ones. The matrix of sporopollenin show a high density in its solid content, water absorption capacity is low (0.18 mL g-1 DM) and it is resistant to deformation. This enable the formation of powder while dehydrating.
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