Des matériaux denses nanostructurés à base de l’alliage métastable Ni-P ont été élaborés par une stratégie "bottom-up" qui combine deux étapes. La première consiste en la préparation de nanoparticules de l’alliage grâce au procédé polyol modifié par l’ajout d’hypophosphite, un agent réducteur fort. Les nanoparticules obtenues sont de morphologie sphérique et de taille variant de 39 à 220 nm. La deuxième étape consiste en la consolidation de ces nanopoudres par le procédé SPS. Les massifs denses obtenus sont constitués de grains polygonaux de nickel (taille variant de 154 à 650 nm) et de nanoparticules sphériques de Ni₃P localisées aux points de jonction triple et aux joints des grains de nickel. Ces nanoparticules de taille ne dépassant pas 250 nm sont formées par un mécanisme de diffusion du phosphore à travers les grains de nickel. Les matériaux denses élaborés présentent les caractéristiques magnétiques d’un ferromagnétisme doux (faible champ coercitif) mais une aimantation à saturation élevée proche de celle du nickel massif. Les propriétés mécaniques sont fonction de la taille des grains. Quand cette taille est faible, les matériaux manifestent une résistance mécanique et une limite élastique élevées accompagnées d’une faible ductilité. Une augmentation de la taille des grains entraine des évolutions inverses conformément à la loi de Hall-Petch. / Dense nanostructured materials based on the metastable Ni- P alloy were prepared by "bottom- up" strategy. This synthesis pathway is the combination of two steps. The first is to prepare the powder by soft chemistry (reduction in polyol medium modified by the addition of hypophosphite a strong reducing agent). The nanoparticles produced have spherical morphology and size ranging from 39 to 220 nm. These powders are metastable solid solutions Ni- P. The second step is to consolidate these powders by SPS process; it results in dense nanostructured material consisting of polygonal grains of nickel (size ranging from 254 to 650 nm) along with spherical nanoparticles Ni3P located at triple junction points and grain boundaries. These nanoparticles of size no greater than 250 nm are formed by a diffusion mechanism through the phosphorous nickel grains. The as-obtained dense materials have magnetic characteristics of a soft ferromagnetism (low coercivity) but a good saturation magnetization close to that of bulk nickel. These materials also exhibit very interesting mechanical properties depending on the grain size. When the grain size is small, the materials exhibit mechanical strength and high elastic limit accompanied by low ductility. An increase in grain size leads to inverse changes in line with the Hall-Petch law.

No description available.

La synthèse de graphène par approche « bottom-up » fait l’objet de nombreux travaux de recherche ayant pour but de contrôler les propriétés électroniques et optiques de ce matériau par la fabrication de nanostructures avec une précision atomique. D’autre part, le contrôle de dopant dans le graphène permettant d’en moduler les propriétés suscite un grand intérêt et dans ce contexte l’utilisation de porphyrines avec un taux d’azote contrôlé est attrayante. Par leurs ressemblances structurelles, les porphyrines π-étendues peuvent être considérées comme des nanoparticules de graphène dopées à l’azote (GQDs) présentant de fortes propriétés infrarouge tandis que les briques de construction à base de porphyrines peuvent être utilisées pour la synthèse sur surface de deux type de nanoarchitectures de graphene appélées nanorubans (GNRs) et nanomèches (GNMs). Cette thèse a pour objectif de développer la synthèse de porphyrines à base d’anthracenes et de les utiliser comme précurseurs pour la fabrication de nanostructures. La première partie de cette thèse est dédiée à la synthèse organique de différentes anthracenylporphyrines et à l’étude de leurs assemblages sur surface dans la chambre d’un microscope à effet tunnel. La seconde partie est dédiée à l’étude de formation de porphyrines π-étendues via une méthode pyrolyse flash pouvant activer thermiquement des réactions de couplage par déhydrogenation entre des hydrocarbures aromatiques polyycliques (PAHs) et des porphyrines. La dernière partie est dédiée à la modification post synthétique d’une tetrabromoanthracenylporphyrine par addition de PAHs via la réaction de couplage de Suzuki-Miyaura et à la caractérisation des propriétés optiques de ces porphyrines nouvellement formées. / The synthesis of graphene via bottom-up approach is a hot topic of research that aims to control the electronic and optical properties of this material by the fabrication of atomically precised nanostructures. Moreover, the control of dopant in graphene is of great interest to modulate the properties of the material. In this context, the contribution of porphyrins with a controlled content of nitrogen is attractive in this context. Because of structural similarities with graphene quantum dots (GQDs), π-extented porphyrins can be regarded as nitrogen-doped GQD with promising NIR properties. Porphyrins are convenient building blocks for the synthesis on surface of nanoarchitectures of graphene called nitrogen-doped Graphene Nanoribbons (GNRs) and Graphene NanoMeshes (GNMs). This thesis aims to develop the synthesis of symmetrical and robust porphyrins with anthracenes and to use them as precursors for the fabrication of nanostructures. The first part of this thesis is dedicated to the organic synthesis of variety of anthracenylporphyrins and the study of their assemblies on surface in a chamber of a Scanning Tunneling Microscope. The second part is dedicated to the study of formation of π-extended porphyrins via a method of flash pyrolysis able to thermally activate dehydrogenative coupling reactions between Polycyclic Aromatic Hydrocarbons (PAHs) and porphyrins. The last part is dedicated to the post synthetic modification of a tetrabromoanthracenylporphyrin with additional PAHs via Suzuki-Miyaura coupling and the characterization of the optical properties of the resulting porphyrins.

Microtubules (MTs), whose basic units are a and ß tubulin proteins, are self-assembled proteinaceous filaments with nanometer scale diameters and micrometer scale lengths. Their aspect ratio, directionality, the reversibility of their assembly and their ability to be metallized by electroless plating make them good candidates to serve as templates for the fabrication of nanowires and other nanoscale devices. In addition, tubulin proteins can provide biological interactions with a naturally high specificity.Toward the goal of manufacturing MT-based metallic nanowires and networks of nanowires on a silicon wafer, I studied the influence of pH, temperature, and several biomolecules on the stability of MTs in solutions, as well as the surface effect on the dynamics of disassembly of microtubules. Secondly, I demonstrated the metallization of MTs by electroless nickel plating both in solution and on hydrophilic oxidized Si surface. After being activated by Pt, nickel coated MT surfaces during the electroless plating, with a thickness of several nanometers. Due to the different kinetics of the process, MTs metallized on the oxidized Si wafer are slightly different from MTs metallized in solutions. Finally, we explored controlled nucleation and growth of microtubules directly from a collection of g-tubulin monomers. g-tubulins bind to modified gold electrodes on a silicon wafer through an organic linker, Glutathione s-transferase, creating a g-tubulin layer for MT growth. MTs unambiguously originated from the surface-bound g-tubulin layer on the gold electrode, proving that the surface-bound g-tubulin retains its biological ability of nucleating MT growth.

No description available.

Made available in DSpace on 2014-06-12T22:58:12Z (GMT). No. of bitstreams: 2 arquivo4277_1.pdf: 4341020 bytes, checksum: 14c9ce1c7a9f4c1c01f64ebee2dd8876 (MD5) license.txt: 1748 bytes, checksum: 8a4605be74aa9ea9d79846c1fba20a33 (MD5) Previous issue date: 2008 / No presente trabalho, foi desenvolvido e caracterizado um sistema híbrido formado pela evaporação térmica de um nanofilme molecular de complexo de terra rara sobre um filme fino metálico, obtido por um processo bottom-up. Para a produção do novo híbrido, o complexo fotônico Eu(btfa)3bipy foi depositado sobre um substrato recoberto por um filme de prata nanoestruturado formado pela redução térmica de íons de prata seguido do crescimento e migração de nanopartículas de prata para a superfície do material vítreo. A luminescência do complexo de terra rara sobre o substrato vítreo foi monitorada em função do tempo de tratamento na temperatura de transição vítrea (Tg), e do crescimento do nanofilme autoformado, este, por sua vez, monitorado por microscopia de força atômica (AFM). Amostras de dois sistemas GAPAgF e GAPAgO foram obtidas pela fusão dos materiais de partida em um forno resistivo, seguido por um tratamento térmico próximo da Tg para produzir um filme de prata nanoestruturado na superfície das amostras, apresentando uma aparência metálica. O novo substrato vítreo ativo GAPAgO possui uma enorme velocidade de crescimento do nanofilme se comparada com a cinética de crescimento do vidro ativo GAPAgF, previamente estudado. O crescimento das nanopartículas foi monitorado por AFM em ambos os sistemas, em função do tempo de tratamento térmico, apresentando o crescimento de nanoestruturas de prata com 100 nm somente em dois minutos de tratamento térmico. A energia de ativação E relacionada com cristalização, e o fator de freqüência υ foi calculado para êtsr composições do sistema GAPAgO. O resultado indica uma instabilidade deste vidro se relacionado com o sistema GAPAgF previamente estudado. A morfologia da superfície foi avaliada em função da atmosfera durante o tratamento térmico. O sistema GAPAgO apresentou uma geometria preferencial de crescimento do nanofilme na superfície do vidro. Medidas de fluorescência do íon Eu3+ no complexo Eu(btfa)3 Palavras chave: Nanopartículas de prata, Plásmons, processo bottom up. bipy foram analisadas como uma função do tempo de tratamento, mostrando um melhor aumento da luminescência em amostras com superfícies mais rugosas. As propriedades fotônicas das amostras foram analisadas, e os sistemas foram caracterizados por DRX, AFM e XPS. O objetivo final deste trabalho é de usar esses novos materiais, como substratos ativos para nanodispositivos

The DNA double helix is inherently a nanoscale wire-like object, possessing a 2 nm diameter as well as a remarkable capability for molecular recognition and the interaction with other chemical compounds, thus making it an attractive material for biologically driven assembly of artificial nanostructures. In this work methods for the construction of functional electronic networks from single DNA molecules are presented. For this, (i) the generation of patterns of distinct interconnects between micro-fabricated contact pads are explored by stretching end-specifically thiol-functionalized, single-tethered DNA molecules using hydrodynamic flow as well as an electric field-induced thermal flow. (ii) These networks then serve as a template for a selective in-situ photoinduced nucleation and growth of platinum clusters of 4 nm diameter along the DNA molecules. In the synthesis exclusively platinum ions from an aqueous platinum nitrate solution bonded electrostatically to the backbone of the immobilized DNA can be reduced upon irradiation with UV light, while background metallization is inhibited. Furthermore, the metallization scheme is applied to DNA nanotubes and another photochemical deposition process is used to tune the interparticle gap space in a discontinuous platinum cluster chain to form conducting nanowires. The "process toolbox'' presented in this work offers a versatile alternative for the hierarchical patterning and incorporation of biotemplated nanomaterials into micro-/nanofabrication schemes. / Ein doppelhelikaler DNA-Strang besitzt mit seinem hohen Aspektverhältnis von Natur aus Ähnlichkeit mit einem Kabel. Zusammen mit seinen einzigartigen Selbstassemblierungseigenschaften sowie der Fähigkeit, mit einer Vielzahl von chemischen Stoffen eine Verbindung einzugehen, macht dies ihn zu einem aussichtsreichen Baumaterial für den Aufbau von künstlichen Nanostrukturen. In dieser Arbeit werden deshalb verschiedene Methoden für den Bau von elektronischen Schaltkreisen aus einzelnen DNA-Strängen demonstriert. Dazu wird (i) die Herstellung von Verdrahtungsmustern zwischen lithographisch gefertigten Kontaktstrukturen untersucht. Endständig mit Thiolgruppen funktionalisierte DNA-Moleküle, die an nur einem Ende mit der Oberfläche verknüpft sind, werden mittels Strömung oder eines elektrothermisch induzierten Flusses zwischen Elektroden gespannt. (ii) Diese Netzwerke dienen im Weiteren als Vorlage für ein selektives, lichtinduziertes Wachstum von Platinpartikeln mit Durchmessern von 4 nm lokal entlang der DNA-Moleküle. Dabei werden unter UV-Bestrahlung nur solche Platinionen reduziert, die aus einer Platinnitrat-Lösung elektrostatisch an die immobilisierte DNA angebunden haben. Partikelwachstum in der umgebenden Lösung wird weitgehend verhindert. Darüber hinaus wird dieses Verfahren auch auf DNA-Nanoröhren angewendet und ein weiterer photochemischer Abscheideprozess eingesetzt, um unterbrochene Clusterkettern zusammenzuwachsen, mit dem Ziel, elektrisch leitfähige Nanodrähte zu erhalten. Die vorgestellten Verfahren stellen eine vielseitige Alternative zu herkömmlichen, hierarchischen Fabrikationsschemen der Mikro- und Nanotechnologie dar.

Det finns två typer av goodwill, den första typen är internt upparbetad goodwill och den andra typen är goodwill som uppkommer vid förvärv av företag. Fokus i denna uppsats kommer att ligga på den förvärvade goodwill, som kan upplevas som en svart låda då det kan vara oklart vad posten faktiskt består av. Förvärvad goodwill kan definieras på olika sätt av företagen, i den akademiska världen har främst två perspektiv identifierats, top-downperspektivet och bottom-upperspektivet. Ur den första synvinkeln ses goodwill som en restpost och ur den andra synvinkeln kan goodwill ses som en summa av de komponenter som posten består av. Genom att betrakta dessa perspektiv är tanken att få en inblick i hur företagen väljer att redovisa sin goodwill. Det kan vara lättare sagt än gjort, teori och praktik går inte alltid hand i hand. Det finns ett glapp mellan hur praktiker jobbar med goodwill och teoretikers åsikt om posten. Varför det finns meningsskiljaktigheter växer successivt fram under studiens gång. Det finns än så länge bara ett fåtal studier som behandlar själva begreppet goodwill och dess olika perspektiv samt hur företagen ser på goodwill. För att försöka bidra till ökad förståelse på detta område, har vi i denna uppsats undersökt om teorin och praktiken kommit varandra närmare. Det främsta syftet med studien är att ta reda på om företag inom bemanningsbranschen definierar sin goodwill olika i sina årsredovisningar. För att undersöka detta på ett begripligt sätt har tre professionella respondenter intervjuats i ett försök att klargöra komplexiteten av posten.   Slutsatsen är att det inte går att identifiera vilket perspektiv som används i en årsredovisning på grund av att dessa är väldigt standardiserade, vilket gör att det blir svårt för intressenten att utläsa särskilt mycket information om goodwillposten.  Det alternativ som kändes mest relevant att använda och som skulle hjälpa oss att kunna få klarhet i vår frågeställning, var att vända sig till en urvalsgrupp av representanter på området. Den analys som efterföljde resulterade i att vi kunde konstatera att samtliga svarande på det praktiska området såg goodwillposten mer eller mindre som en restpost. Ingen värdering eller starkare reflektion gjordes kring det andra teoretiska perspektivet. Sammanfattningsvis vågar vi påstå att det inte skett någon märkbar förändring som gjort att teori och praktik närmat sig varandra. / There is two ways to understand goodwill. Number one, internally generated goodwill and number two, acquired purchase goodwill. The main topic for this research is acquired purchase goodwill. Many people believe that goodwill is a sort of black box.  It is unclear what goodwill actually is. There is no limit on how you can define acquired purchase goodwill. In academia we talk about two perspectives, top-down perspective and bottom-up perspective. The first perspective sees goodwill as a residual and the second perspective sees goodwill as a sum of its components. When you put on these two glasses, the idea is that you may be able to see how businesses account for their goodwill. It is easier said than done, many times theory and practice does not get along. There is a big space between the theories on how you work with goodwill in the reality. Only a few have studied the definition of goodwill. Because of that we really wanted to investigate this phenomenon. We have analyzed if the gap between theory and reality has been reduced. The purpose of this study is to investigate if the staffing companies define goodwill different in their annual reports. The tool we have used is to interview professional accountants to get their opinion. The conclusion is that the annual report is quite standardized which means it is difficult to understand what goodwill actually is. Everybody we interviewed have the same opinion, that goodwill is a residual. They made no reflections or additions on that subject. In summary, we know now that after our study, no big change has been made between theory and practice.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / O picoplâncton (0,2 - 2,0 m) e ultraplâncton (> 2,0 - 5,0 m) despertam interesse por utilizarem ativamente a matéria orgânica dissolvida, estabelecendo a alça microbiana. Responsáveis por 50-80% da produção primária em águas oligotróficas, essas frações apresentam elevadas eficiência luminosa e razão superfície/volume que as permitem alcançar alto desenvolvimento mesmo sob baixas luminosidade e disponibilidade de nutrientes. Buscando relacionar a distribuição espacial e composição da comunidade pico e ultraplanctônica aos controles bottom-up na plataforma continental e talude ao largo dos Estados do Rio de Janeiro e São Paulo (22S a 26S), foram coletadas amostras de água em 39 estações oceanográficas e utilizadas as imagens dos sensores MODIS Terra e Aqua, bem como dados de hidrografia, para a descrição dos fenômenos oceanográficos de mesoescala. A abundância total de ambas as frações de tamanho, assim como a dominância do picoplâncton, reduziu em função do distanciamento da costa. Os organismos autotróficos foram em média (102 cél.mL-1 a 104 cél.mL-1 ) majoritariamente uma ordem de grandeza inferiores aos heterotróficos (103 cél.mL-1 a 105 cél.mL-1). A Água Central do Atlântico Sul (ACAS) e as plumas das baías de Guanabara e Sepetiba (RJ) permaneceram na plataforma interna favorecendo o aumento na concentração dos macronutrientes e refletindo na mudança da estrutura da comunidade através do aumento da contribuição de autótrofos no centro da plataforma, principalmente do ultraplâncton à superfície (cerca de 21%) e na profundidade do máximo de clorofila (44%). O transporte de águas costeiras carreadas por uma corrente de origem sul gerou o vórtice de plataforma identificado nas imagens de satélite para a região da plataforma interna de Ubatuba (SP), onde concentrações mais elevadas de amônio (0,28 M) e fosfato (9,64 M) a partir dos 50 m sustentaram maior densidade do ultra autótrofo (2,89 x 103 cél.mL-1) que superou a densidade de heterótrofos (2,50 x 103 cél.mL-1) no máximo de clorofila. Os resultados destacaram um forte gradiente nerítico-oceânico na distribuição dos organismos. Sugerem ainda a predominância do metabolismo heterotrófico na maior parte das águas oligotróficas da plataforma e talude entre o Rio de Janeiro e São Paulo, bem como a presença de caráter autotrófico naquelas regiões influenciadas por feições de mesoescala, como plumas estuarinas e vórtices de plataforma. / The picoplankton (0.2 2.0 m) and ultraplankton (>2.0 5.0 m) arouse interest because they actively use the dissolved organic matter and establishe the microbial loop. Responsible for 50-80% of primary production in oligotrophic waters, these fractions have high luminous efficiency and high surface/volume ratio that enable them to achieve high development even under low light and low nutrient availability. Seeking to relate the spatial distribution and composition of pico and ultraplanktonic community to the bottom-up control and mesoscale oceanographic features in the Brazilian continental shelf and slope off Rio de Janeiro and São Paulo (22S to 26S), water samples were taken in 39 oceanographic stations and images of MODIS Terra and Aqua sensors, toghether with hidrography, were employed to decribe the mesoscale oceanographic features.The total abundance of both size fractions, as well as the dominance of picoplankton, decreased as a function of distance from the coast. Autotrophic organisms were, predominantly, on average (102 cell.mL-1 to 104 cell.mL-1) one order of magnitude lower than the heterotrophic (103 cell.mL-1 to 105 cell.mL-1). The South Atlantic Central Water (SACW) and the plumes of Guanabara and Sepetiba bays (RJ) remained in the inner shelf favoring an increase in macronutrients concentration and reflecting changes in community structure by the increase of autotrophs contribution, especially in the central portion of the shelf, mainly ultraplankton at surface (21%) and in maximum chlorophyll depth (44%). The transport of coastal waters carried by a current from south caused the shelf eddy identified by water colour/chlorophyll images for the region of Ubatuba inner shelf (SP), where high concentrations of ammonium (0,28 M) and phosphate (9,64 M) near the depth of 50 m supported higher density of autotrophic ultraplankton (2.89 x 103 cells.mL-1) which exceeded the density of heterotrophs at the chlorophyll maximum (2.19 x 103 cells.mL-1). Our results highlighted a strong neritic-oceanic gradient in the distribution of these organisms. They also suggest the predominance of the heterotrophic metabolism in the majority of the oligotrophic waters of the shelf and slope between Rio de Janeiro and São Paulo, as well as the presence of an autotrophic nature in those regions influenced by mesoscale features, such as estuarine plumes and shelf eddies.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / O picoplâncton (0,2 - 2,0 m) e ultraplâncton (> 2,0 - 5,0 m) despertam interesse por utilizarem ativamente a matéria orgânica dissolvida, estabelecendo a alça microbiana. Responsáveis por 50-80% da produção primária em águas oligotróficas, essas frações apresentam elevadas eficiência luminosa e razão superfície/volume que as permitem alcançar alto desenvolvimento mesmo sob baixas luminosidade e disponibilidade de nutrientes. Buscando relacionar a distribuição espacial e composição da comunidade pico e ultraplanctônica aos controles bottom-up na plataforma continental e talude ao largo dos Estados do Rio de Janeiro e São Paulo (22S a 26S), foram coletadas amostras de água em 39 estações oceanográficas e utilizadas as imagens dos sensores MODIS Terra e Aqua, bem como dados de hidrografia, para a descrição dos fenômenos oceanográficos de mesoescala. A abundância total de ambas as frações de tamanho, assim como a dominância do picoplâncton, reduziu em função do distanciamento da costa. Os organismos autotróficos foram em média (102 cél.mL-1 a 104 cél.mL-1 ) majoritariamente uma ordem de grandeza inferiores aos heterotróficos (103 cél.mL-1 a 105 cél.mL-1). A Água Central do Atlântico Sul (ACAS) e as plumas das baías de Guanabara e Sepetiba (RJ) permaneceram na plataforma interna favorecendo o aumento na concentração dos macronutrientes e refletindo na mudança da estrutura da comunidade através do aumento da contribuição de autótrofos no centro da plataforma, principalmente do ultraplâncton à superfície (cerca de 21%) e na profundidade do máximo de clorofila (44%). O transporte de águas costeiras carreadas por uma corrente de origem sul gerou o vórtice de plataforma identificado nas imagens de satélite para a região da plataforma interna de Ubatuba (SP), onde concentrações mais elevadas de amônio (0,28 M) e fosfato (9,64 M) a partir dos 50 m sustentaram maior densidade do ultra autótrofo (2,89 x 103 cél.mL-1) que superou a densidade de heterótrofos (2,50 x 103 cél.mL-1) no máximo de clorofila. Os resultados destacaram um forte gradiente nerítico-oceânico na distribuição dos organismos. Sugerem ainda a predominância do metabolismo heterotrófico na maior parte das águas oligotróficas da plataforma e talude entre o Rio de Janeiro e São Paulo, bem como a presença de caráter autotrófico naquelas regiões influenciadas por feições de mesoescala, como plumas estuarinas e vórtices de plataforma. / The picoplankton (0.2 2.0 m) and ultraplankton (>2.0 5.0 m) arouse interest because they actively use the dissolved organic matter and establishe the microbial loop. Responsible for 50-80% of primary production in oligotrophic waters, these fractions have high luminous efficiency and high surface/volume ratio that enable them to achieve high development even under low light and low nutrient availability. Seeking to relate the spatial distribution and composition of pico and ultraplanktonic community to the bottom-up control and mesoscale oceanographic features in the Brazilian continental shelf and slope off Rio de Janeiro and São Paulo (22S to 26S), water samples were taken in 39 oceanographic stations and images of MODIS Terra and Aqua sensors, toghether with hidrography, were employed to decribe the mesoscale oceanographic features.The total abundance of both size fractions, as well as the dominance of picoplankton, decreased as a function of distance from the coast. Autotrophic organisms were, predominantly, on average (102 cell.mL-1 to 104 cell.mL-1) one order of magnitude lower than the heterotrophic (103 cell.mL-1 to 105 cell.mL-1). The South Atlantic Central Water (SACW) and the plumes of Guanabara and Sepetiba bays (RJ) remained in the inner shelf favoring an increase in macronutrients concentration and reflecting changes in community structure by the increase of autotrophs contribution, especially in the central portion of the shelf, mainly ultraplankton at surface (21%) and in maximum chlorophyll depth (44%). The transport of coastal waters carried by a current from south caused the shelf eddy identified by water colour/chlorophyll images for the region of Ubatuba inner shelf (SP), where high concentrations of ammonium (0,28 M) and phosphate (9,64 M) near the depth of 50 m supported higher density of autotrophic ultraplankton (2.89 x 103 cells.mL-1) which exceeded the density of heterotrophs at the chlorophyll maximum (2.19 x 103 cells.mL-1). Our results highlighted a strong neritic-oceanic gradient in the distribution of these organisms. They also suggest the predominance of the heterotrophic metabolism in the majority of the oligotrophic waters of the shelf and slope between Rio de Janeiro and São Paulo, as well as the presence of an autotrophic nature in those regions influenced by mesoscale features, such as estuarine plumes and shelf eddies.