L'objectif de ce travail est de réaliser des substrats pour l’effet SEIRA (surface enhanced IR absorption) pour mesurer de faibles volumes de gaz ambiants possédant une signature moléculaire de 3,3 μm à 5,1 μm en exploitant la forte amplification de champ électrique due à la résonance plasmon de surface localisés. A cette fin, nous avons démontré la modulation des résonances de plasmon de surface localisées MIR (LSPR) dans les nanocristaux de ZnO dopés (NCs) dopés à Ga ou Al ainsi que dans des nanofils (NWs) de ZnO dopés Ga (GZO) et dans des nanofils coeur/coquille de ZnO/GZO. En ce qui concerne l’accordabilité de MIR LSPR dans les NC, nous avons modulé la résonance plasmon de surface dans des NC de ZnO dopés Ga et Al, de 3 à 5 μm en faisant varier la teneur en Al et en Ga de 3 à 9 at.%. L’incorporation des dopants s’est révélée homogène jusqu’à 6%. Au-delà (9%), l’incorporation était fortement hétérogène, révélant que la limite de solubilité était atteinte. Les NC présentent une faible activation des impuretés. L'activation était aussi faible que 8%. Les LSPR présentaient également un fort élargissement (largeur-à-mi-hauteur FWHM). Pour accroitre l'activation des dopants, nous avons synthétisés les NC dans des conditions pauvres en O et en passivant les NC synthétisés dans des conditions riches en O (en les isolant dans des matrices telles que Al2O3 et SiO2). Nous avons ainsi augmenté l'activation de 8% à 20% pour les deux stratégies. De plus, l'incorporation des NC dans les matrices a réduit l'élargissement spectral de moitié (de 2200 cm-1 pour les NC déposés à 1100 cm-1 pour les NC noyés en matrice). En correspondance, les effets d’auto-assemblage des nanocristaux sur leur LSPR ont été modélisés par simulation FDTD. Cela a fourni des indications quant aux mécanismes responsable de l’élargissement inhomogènes des LSPR de nanocristaux de GZO. Outre les nanoparticules, nous avons étudié des nanofils ZnO dopés Ga (GZO) et coeur/coquille (ZnO/GZO) synthétisés par CVD d’organométalliques . La première conclusion importante est que le gallium produit un fort effet surfacatnt lors de la croissance MOCVD de GZO. Au lieu de former des nanofils de section hexagonale, l’introduction de Ga modifie nettement l’énergie de surface des faces latérales et conduit à al formation de structures de type « sapins de Noël ». Ce constat est aussi valable pour les coquilles de GZO déposées sur coeur de ZnO. Dans ce cas, les coquilles démouillent et forment des structures hiérarchiques en branches. Concernant les propriétés optiques de ces objets, les mesures de FTIR-photo acoustiques ont démontré une signature d’absorption reliée à la présence de Ga et pouvant être accordée selon la teneur en Ga. Cette absorption reproduit le comportement d’une résonance plasmon de surface. Cette résonance a pu être accordée de 1600 à 1900 cm-1. / The scope of this thesis is about developing SEIRA (surface enhanced IR absorption) platform to probe low volumes of environmental gases that possess molecular signature from 3.3 μm to 5.1 μm leveraging the high field amplification of localised surface plasmon resonance (LSPR). To realise SEIRA, we demonstrated tuning MIR LSPR in Al or Ga doped ZnO nanocrystals (NCs) as well as in GZO or core-shell (ZnO/GZO) nanowires (NWs). Regarding tuning MIR LSPR in NCs, we demonstrated tunable MIR LSPR in Ga and Al doped ZnO NCs from 3 to 5 μm varying the Al or Ga content from 3 to 9 at.%. The incorporation of dopant was homogeneous up to 6%. At 9% dopant concentration, the incorporation was inhomogeneous, revealing the solubility limit has been reached. However, the NCs exhibited low activation of impurities. The activation was as low as 8%. The LSPR were characterised by large broadening as well. In order to enhance the dopant activation, we synthesized the NCs in O-poor conditions as well as passivated the NCs fabricated in O-rich condictions (by isolating and embedding them in matrices such as Al2O3 and SiO2 matrices). Both strategies improved the dopant activation from 8% up to 20%. Moreover, for assemblies of NCs dispersed in matrices, the broadening (FWHM) of the LSPR was reduced by half (from 2200 cm-1 in as-deposited NCs to 1100 cm-1 in embedded NCs). Correspondingly, the effect of the self-assembly of the nanocrystals on their LSPR was modeled by FDTD simulation and provided hindsight into the mechanisms responsible for the heterogeneous broadening of the LSPR. Finally, we have studied Ga-doped ZnO (GZO) and core-shell (ZnO/GZO) NW synthesized by MOCVD. The first important conclusion is that Ga plays a major surfactant role during the MOCVD growth of GZO. Instead of leading to hexagonal NWs, the introduction of Ga during the synthesis led to faceted “Christmas-tree” like architectures. The same observation held for core-shell ZnO-GZO nanowires; in the latter case, the GZO shell resulted in a dewetting branched architecture. Regarding their optical properties, photo-acoustic FTIR measurements revealed an absorption feature related to the Ga content, likely to be assigned to a plasmonic effect. This resonance could be tuned from 1600 to 1900 cm.

Thesis (MSc)--Stellenbosch University, 2015. / ENGLISH ABSTRACT: Soil is one of the most complex and understudied terrestrial habitats, and it comprises a wide range of organisms that affect the functioning of terrestrial ecosystems. Despite the importance of these below-ground fauna, our understanding of this diversity remains limited, especially in the Cape Floristic Region (CFR), where higher plants and other more conspicuous invertebrates have been better represented in the literatures. The main aim of this thesis is to provide the first insights into the taxonomic, cryptic and spatial diversity of one of the more diverse Collembola genera, Seira (Collembola: Entomobryidae: Seirinae), in the Fynbos and Southern Afrotemperate forest habitats of the CFR. Collembola constitute an important component of terrestrial biodiversity and are essential for ecosystem functioning. The thesis is divided into two data chapters. The first data chapter examines the mitochondrial barcoding COI (Cytochrome-c oxidase subunit I) gene of 496 Seira specimens from 41 Fynbos and forest sites. Discrete Molecular Operational Taxonomic Units (MOTUs) are identified within Seira. Furthermore, divergence times are estimated and tentatively used to propose historical triggers for the diversification of Seira. Habitat specificity of Seira is assessed through phylogenetic reconstruction using Parsimony and Bayesian analyses based on the nucleotide and amino acid sequences. Genetic divergence indicates that Seira is composed of at least 91 MOTUs, suggesting that morphological taxonomy has vastly under-estimated the richness of this genus by at least four folds. Most of the MOTUs are highly habitat specific and geographically localised. The reconstruction of an evolutionary time frame of these lineages reveals several deep diversifications in the Miocene and a spate of more recent radiations in the Pleistocene and Holocene. Palaeo-environmental fluctuations and vegetation composition shifts are hypothesised as having increased the environmental complexity of the region and this may have influenced the diversification patterns of Seira. In the second data chapter, the spatial variation of Seira diversity is examined and compared between and within two major habitat types, Fynbos and forest, across nine study sites. Abiotic variables were recorded and compared for the investigation of environmental differences among habitat types. The habitat specificity of Seira is assessed, as well as the relative effects of habitat types and study sites on assemblage structure. Species richness of Seira is higher in Fynbos than in forest, and this could be due to the high heterogeneity of niches and resources created by the steep environmental and floristic gradients in the Fynbos habitats. Perhaps one of the most striking results is the high levels of beta diversity exhibited by Seira. The spatial turnover of the Seira assemblage is complete or nearly complete among and within habitat types across study sites within the CFR. Low dispersal abilities and consequently isolated evolutionary histories may account for the strong assemblage differences within the same habitat type of different study sites. However, the substantial differences in assemblage composition between adjacent habitat types in the same site are likely to be the result of the contrasting abiotic conditions exhibited by the Fynbos and forest habitats, as found by this study. Overall, the results of this thesis suggest that Seira species richness is much greater than previously thought. It follows similar diversity patterns to the well-described and hyper-diverse plant communities of the CFR. Here, for both CFR plants and Seira, the spectacular regional diversity displayed is not the result of high alpha diversity, but rather of substantial beta diversity. Because of the high beta diversity and the fact that only two CFR vegetation types were sampled from a limited number of study sites, I predict that the Seira species richness presented here is but the tip of the iceberg. / AFRIKAANSE OPSOMMING: Geen opsomming beskikbaar

Made available in DSpace on 2014-12-17T15:49:11Z (GMT). No. of bitstreams: 1 NerivaniaNG_DISSERT.pdf: 4462053 bytes, checksum: bf282e929e5cb41585970850c4d05edb (MD5) Previous issue date: 2013-03-25 / The family Entomobryidae is one of the most diverse families of Collembola in Northeast Brazil. Data on its diversity may be considered undervalued due to low collection efforts in the region. In this study, five areas in the Northeast region were sampled, to evaluate the species richness of this family. The study was done in the Serra da Jib?ia, Santa Terezinha municipality, Bahia; Serra das Confus?es, Caracol municipality, Piau?; Chapada do Araripe, Crato municipality, Cear?; Mata do Pau-Ferro, Areia municipality, Para?ba and Parque Nacional de Ubajara, Ubajara municipality, Cear?, all considered humid areas of Caatinga. Collections were made using pitfall traps and entomological aspirators. All the collected material was screened, mounted on slides, identified and, finally, the descriptions of some of the new species encountered were made. A total of 48 Entomobryidae species belonging to nine genera were recorded and 27 of these were new to science, representing a percentage of 56.25% of the total. A new record for Brazil was identified and several new records were made to the States. Seira was the genus with wider distribution and it was the only one found in all areas and the most representative with the highest number of recorded species (26). This result was expected, because individuals of the genus Seira have a good adaptability to semi-arid environments, a fact that has already been proven in previous research. Seven new species of Seira were described. A dichotomous key to genera and species of Seirini from Brazil was drafted. This work demonstrates the great potential of Entomobryidae and Seirini in the Northeast, despite having been held in very restricted areas, obtained important results for the knowledge of fauna of the group / A fam?lia Entomobryidae ? uma das mais diversas fam?lias de Collembola do Nordeste Brasileiro. Dados sobre sua diversidade podem ser considerados subestimados devido ao baixo esfor?o de coleta na regi?o. No presente estudo, foram realizadas coletas em cinco localidades do Nordeste, nunca antes amostradas, objetivando avaliar a riqueza de esp?cies desta fam?lia. O estudo foi feito na Serra da Jib?ia, munic?pio de Santa Teresinha, Bahia; Serra das Confus?es, munic?pio de Caracol, Piau?; Chapada do Araripe, mun?cipio do Crato, Cear?; Mata do Pau-Ferro, munic?pio de Areia, Para?ba; e Parque Nacional de Ubajara, munic?pio de Ubajara, Cear?, todas consideradas ?reas ?midas da Caatinga. As coletas foram feitas utilizando-se armadilhas de queda do tipo pitfall e aspiradores entomol?gicos. Todo o material coletado foi triado, montado em l?minas, identificado e, por fim, foram feitas as descri??es de algumas das esp?cies novas encontradas. Um total de 48 esp?cies de Entomobryidae pertencentes a nove g?neros foram registradas e 27 destas s?o esp?cies novas para a ci?ncia, o que representa um percentual de 56,25% do total. Um novo registro de esp?cie para o Brasil foi identificado e novos registros para os estados foram feitos. O g?nero que possuiu distribui??o mais ampla foi Seira, o ?nico encontrado em todas as ?reas e o mais representativo com o maior n?mero de esp?cies registradas (26). Esse resultado j? era esperado, pois indiv?duos do g?nero Seira possuem uma boa adaptabilidade a ambientes semi-?ridos, fato que j? foi comprovado em pesquisas anteriores. Sete novas esp?cies do g?nero Seira foram descritas. Uma chave dicot?mica de identifica??o dos g?neros e esp?cies de Seirini com ocorr?ncia no Brasil foi elaborada. Este trabalho demonstrou o grande potencial de Entomobryidae e Seirini no Nordeste, visto que, apesar de ter sido realizado em ?reas bem restritas, obteve resultados importantes para o conhecimento da fauna do grupo

Made available in DSpace on 2014-12-17T15:37:17Z (GMT). No. of bitstreams: 1 AilaSF_DISSERT.pdf: 2602874 bytes, checksum: 17786cedd4c6cf455a1bade82e0156e9 (MD5) Previous issue date: 2013-03-25 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / Collembola is one of the most abundant and diverse group of terrestrial arthropods, being at the base of the food chain operating in the decomposition process. They have a wide distribution in the world and can be found in practically all habitats. The knowledge of this distinctive fauna is still deficient in brazilian territory, especially in semi-arid region. The aim of this study was to investigate which climatic variables may act as predictors of species richness, abundance of individuals and compositional structure of the taxocenose of Collembola over 12 months in an area dominated by semi-arid Caatinga vegetation, northeastern Brazil and describe new species of the genus Seira found, more diverse taxon of Collembola in Brazil. Samples were collected in Jo?o C?mara, Rio Grande do Norte. Ten plots of 20 x 20 meters were established and the specimens were collected with collection effort of one hour/people using entomological aspirator. The identification and description of the species was carried out by studying the morphology and chaetotaxy. Was performed a multiple regression analysis between species richness and abundance of individuals with climatic variables. A total of 1231 individuals belonging to 15 species, 12 genera and nine families. The greatest richness and abundance of Collembola were found during the rainy season. The genus Seira was the most abundant. Rainfall explained the temporal variation in species richness and abundance of Collembola in the semi-arid region, which is consistent with the biology of these animals. The populations of Collembola showed grouped distribution. Three new species of Seira were described and illustrated and all show similarities with species already registered in the national territory / Collembola constitui um dos grupos mais abundantes e diversos de artr?podes terrestres, estando na base da cadeia alimentar e atuando no processo de decomposi??o. Possuem ampla distribui??o no mundo e podem ser encontrados em praticamente todos os habitats. O conhecimento desta distinta fauna ainda ? deficiente em territ?rio brasileiro, especialmente no semi?rido. O objetivo desse estudo foi investigar quais as vari?veis clim?ticas podem atuar como preditoras da riqueza de esp?cies, abund?ncia de indiv?duos e da estrutura composicional da taxocenose de Collembola ao longo de 12 meses em uma ?rea semi?rido dominada por vegeta??o de Caatinga, Nordeste brasileiro; e descrever novas esp?cies encontradas do g?nero Seira, t?xon mais diverso de Collembola no Brasil. As coletas foram realizadas em Jo?o C?mara, Rio Grande do Norte. Dez parcelas de 20 x 20 metros foram estabelecidas e os esp?cimes foram coletados com esfor?o de coleta de uma hora por pessoa utilizando um aspirador entomol?gico. A identifica??o e descri??o das esp?cies foram realizadas atrav?s do estudo da morfologia e quetotaxia dos exemplares. Foi realizada uma an?lise de regress?o m?ltipla entre a riqueza de esp?cies e a abund?ncia de indiv?duos com as vari?veis clim?ticas. Foi coletado um total de 1231 indiv?duos, distribu?dos em 15 esp?cies, 12 g?neros e nove fam?lias. As maiores riqueza e abund?ncia de Collembola foram encontradas durante a esta??o chuvosa. O g?nero Seira foi o mais abundante. A precipita??o explicou varia??o temporal da riqueza de esp?cies e abund?ncia de Collembola no semi?rido, o que condiz com a biologia desses animais. As popula??es de Collembola apresentaram distribui??o agrupada. Tr?s esp?cies novas de Seira foram descritas e ilustradas e todas apresentam semelhan?as com esp?cies j? registradas em territ?rio nacional

La mise au point de capteurs optiques moyen infrarouge (MIR) pour la surveillance des polluants organiques dans l'environnement aquatique est actuellement un défi de grande importance. Les capteurs MIR basés sur la spectroscopie à ondes évanescentes sont des outils d'analyse prometteurs pour la détection et la quantification simultanées d'une variété de polluants tels que les composés hydrocarbonés. Les verres de chalcogénure sont particulièrement bien adaptés aux applications de détection en raison de leur large domaine de transparence (jusqu'à 10-16 µm en fonction de leur composition). Ainsi, des films minces de chalcogénure pour le développement de plates-formes optiques intégrées ont été synthétisés. Leur fonctionnalisation par des polymères afin d'augmenter la sensibilité des capteurs a également été réalisée. Parmi les compositions de verre (GeSe2)100-x(Sb2Se3)x, deux cibles en verre séléniure ont été choisies pour leurs propriétés optiques et physiques. Grâce à la spectroscopie de réflexion totale atténuée, des mesures ont été effectuées dans l'eau pour détecter les hydrocarbures aromatiques (benzène, toluène et les trois isomères du xylène) dans des concentrations comprises entre 250 ppb et 40 ppm. Des mesures de détection ont également été effectuées à l'aide d'eau de mer et d'eau souterraine. Pour augmenter leur sensibilité, l'utilisation de nanoparticules métalliques est l'une des solutions prometteuses basées sur l'absorption infrarouge améliorée en surface (SEIRA). Ainsi, des structures hybrides combinant nanoparticules d'or déposées sur des verres de chalcogénure ont été fabriquées et caractérisées. / The development of middle-infrared (MIR) sensors for organic pollutants monitoring in the aquatic environment is currently a challenge of great importance. The mid-infrared sensor based on evanescent wave spectroscopy is a promising analytical tool for simultaneous detection and quantification of a variety of pollutants such as hydrocarbon compounds. Chalcogenide glasses are particularly well adapted for sensing applications due to their wide domain of transparence (up to 10-16 µm depending on their composition). The aims of this study are to synthetize chalcogenide thin films for developing mid-infrared optical integrated platforms and perform their functionalization with polymers in order to increase the sensor sensitivity. Among (GeSe2)100-x(Sb2Se3)x glass compositions, two selenide glass targets were chosen for their optical and physical properties. Thanks to attenuated total reflection spectroscopy, measurements were performed in water to detect aromatic hydrocarbons (benzene, toluene and the three xylene isomers) in the concentrations range of 25 ppb to 10 ppm. Detection measurements have also been fulfilled using seawater and ground-water. To increase their sensitivity, the use of metallic nanoparticles is one of the promising solutions based on Surface Enhanced Infrared Absorption (SEIRA). Thus, hybrid structures combining gold nanoparticles/chalcogenide glass and waveguides were fabricated and characterized.

The overarching objective of the investigations discussed herein is the development of a model experimental system for surface-enhanced infrared absorption (SEIRA) spectroscopy, with potential applicability in higher order infrared spectroscopic techniques, specifically, surface-enhanced two-dimensional infrared (SE-2D IR) spectroscopy. Theoretical predictions that accurately predict the stability of functionalized nanoparticles enable guided design of their properties but are often limited by the accuracy of the parameters used as model inputs. Hence, first, such parameterization limitations for the extended DLVO (xDLVO) theory are overcome using a size-dependent Hamaker constant for gold, interfacial surface potentials, and tilt angles of self-assembled monolayers (SAMs), which collectively improves the predictive power of xDLVO theory for modeling nanoparticle stability. Measurements of electrical properties of functionalized gold nanoparticles validate the predictions of xDLVO theory using these new parameterizations illustrating the potential for this approach to improve the design and control of the properties of functionalized gold nanoparticles in various applications. Next, a series of experiments were conducted to elucidate the behavior of various infrared active molecules in the presence of spherical gold nanoparticles of average diameter ∼20 nm. Here, the spectroscopic anomalies, specifically the shifted vibrational frequency and the dispersive lineshape observed in the infrared spectra for SCN- in the presence of gold nanoparticles provide direct evidence of SIERA. Nevertheless, it was evidenced that nanomaterial with plasmonic properties that extends into the infrared wavelengths are imperative in observing efficient infrared enhancements. Hence, nanomaterial indicating plasmonic properties extending into the infrared wavelengths were synthesized via a straightforward, seedless, one-pot synthesis. The gold nanostars prepared here indicated plasmonic behavior clearly extending into the near infrared, with simple plasmonic tunability via changing the buffer concentration used during synthesis. The systematic understanding achieved here in terms of theoretical prediction of nanoparticle stability, origin of infrared spectral anomalies in the presence of nanomaterials, and the preparation of infrared plasmonic material, collectively provides a resilient framework for the further investigation of surface-enhanced infrared spectroscopic techniques including SEIRA and SE-2D IR spectroscopies.

La détection et l'identification des substances biologiques ou chimiques peuvent être accomplies par des biocapteurs. On exige des biocapteurs d'être simple et rapide à utiliser, d'avoir une taille réduite, et d'être suffisamment sensible afin de pouvoir détecter des molécules en petite quantité. Des dispositifs plasmoniques se sont révélés adaptés pour l'usage en tant qu'élément transducteur des biocapteurs. Les plasmon-polaritons de surface (SPP) sont des oscillations collectives du nuage électronique des métaux, couplées à des ondes électromagnétiques. Leur fréquence de résonance dépend de l'indice de réfraction de leur environnement diélectrique. Ceci permet de sonder de manière efficace la présence des molécules par la modification de l'indice de réfraction engendrée par celles-ci. La technique reposant sur ce principe s'appelle la détection par résonance des plasmons de surface (SPR sensing en anglais). De plus, les SPP confinent le champ électrique incident à des volumes sub-longueurs d'onde et l'exaltent ainsi. Les molécules qui se situent dans ces zones de forte exaltation du champ électrique interagissent plus efficacement avec la lumière incidente par l'intermédiaire du SPP, tel que leur section efficace de l'absorption infrarouge (IR) augmente. La spectroscopie IR est une technique standard d'identification de molécules en quantités suffisantes. Pour améliorer la sensibilité, la spectroscopie vibrationnelle d'absorption exaltée par la surface (SEIRA pour surface enhanced infrared absorption en anglais) est particulièrement bien adaptée.Alors que la plasmonique s'est principalement développée dans le visible via les métaux nobles, les semi-conducteurs III-V fortement dopés présentent une alternative intéressante pour la plasmonique dans le moyen IR. Leur fonction diélectrique ressemble à celle des métaux nobles dans le visible, mais décalée dans le moyen IR. Leur densité de charges moindre que celle de l'or permet de réduire considérablement leurs pertes. La spectroscopie SEIRA utilise des nanoantennes plasmoniques dont les résonances se situent dans l'IR pour couvrir la gamme spectrale des modes vibrationnels moléculaires. L'InAsSb fortement dopé accordé en maille sur un substrat en GaSb présente des propriétés plasmoniques au-delà de 5 µm de longueurs d'onde.Dans ce manuscrit, nous proposons des nanostructures en InAsSb:Si/GaSb pour développer un biocapteur utilisant les techniques de SEIRA et de SPR "sensing". Les nanostructures ont été réalisées soit par photolithographie et gravure chimique humide soit par lithographie interférentielle et gravure par plasma réactif. Les caractérisations optiques ont été effectuées par spectroscopie IR à transformée de Fourier. Des calculs numériques par la méthode des différences finies dans le domaine temporel (FDTD) ont permis d'étudier l'effet des paramètres géométriques sur la réponse optique des structures. Deux types de structure ont été proposés : des réseaux unidimensionnels ainsi que des réseaux bidimensionnels de nanoantennes rectangulaires supportant des résonances de plasmon de surface localisé (LSPR) dans les deux directions de polarisation de la lumière par rapport aux axes de la structure. Ce type de structures permet ainsi une réponse optique ayant des résonances dans deux bandes spectrales différentes. Les techniques de SPR "sensing" et de SEIRA ont été démontrées pour l'ensemble des structures uni- et bidimensionnelles. Différents types d'analytes comme les polymères et le benzaldéhyde vanilline ont servi de systèmes de tests pour les structures plasmoniques. Les sensibilités se situent entre 10² et 10^3 nm/RIU. Les facteurs d'augmentation des signaux vibrationnels obtenus sont compris dans une gamme de 1,2 à 5,7 et les facteurs d'exaltation ont été évalués autour de 10^3 à 10^4 pour les réseaux bidimensionnels de nanoantennes plasmoniques. / The detection and identification of biological and chemical substances can be performed with biosensors. Biosensors are required to be simple and rapid to use, small, and sensitive in order to detect minute amounts of analyte molecules. Plasmonic devices have proven their utility as biosensing transducers. Surface plasmon-polaritons (SPP), collective oscillations of the electron cloud in metallic media coupled to an electromagnetic wave, are sensitive to the refractive index of their environment, providing thus an efficient way to probe the presence of molecules by the refractive index modification. This technique is called surface plasmon resonance (SPR) sensing. Moreover, SPP confine the incident electric field to sub-wavelength dimensions and enhance the field strength. Molecules located in these so-called field hotspots interact more efficiently with incident light due to a coupling mechanism mediated by the SPP, so that their infrared (IR) absorption cross section is increased. While IR spectroscopy is a standard tool for molecular identification, it does not provide sufficient sensitivity for the detection of smallest quantities. Exploiting the surface enhanced IR absorption (SEIRA) due to the plasmonic enhancement enables the detection of small amounts of analyte.While surface plasmons were mainly discovered using noble metals such as gold and silver, nowadays other material systems are also considered which display complementary or improved properties compared to the standard materials in plasmonics, especially to enlarge the spectral range where plasmonic effects can be observed and exploited. Material science enables to tailor the dielectric function of a material and consequently to control the plasmonic properties. Highly doped III-V semiconductors constitute an alternative to gold and silver for mid-IR plasmonics, due to their dielectric function which resembles the one of the noble metals, but shifted to the mid-IR spectral range. Indeed, InAsSb in the IR is even less lossy than gold in the visible. SEIRA using plasmonic resonances spectrally tuned to molecular absorption lines, or resonant SEIRA, requires nanoantenna substrates displaying their resonances in the IR. Highly doped InAsSb grown lattice matched on GaSb substrates is an interesting material system for this task. InAsSb is plasmonic for wavelengths above approximately 5 µm.In this work, we propose InAsSb:Si/GaSb nanostructures as SEIRA and SPR substrates for an application in biosensing devices. InAsSb nanoantennas on GaSb substrates have been prepared using photolithography and wet chemical etching by a citric acid: hydrogen peroxyde solution or alternatively, by interferential lithography and reactive ion etching, especially to reduce the lattice parameter. An optical characterization of the structures was performed by FTIR spectroscopy, supported by numerical finite-difference time-domain (FDTD) calculations which were also applied to study the impact of geometrical parameters on the optical response. Notably, two types of structure designs were proposed: one-dimensional periodic gratings and two-dimensional arrays of rectangular shaped nanoantennas which provide localized surface plasmon resonances (LSPR) in both polarization directions contrary to the gratings and enable hence a dual band optical response. SPR sensing and SEIRA have successfully been demonstrated using both types of structures, with proof-of-concept analytes such as different polymers and the aromatic compound vanillin with absorption features at high IR wavelengths. A bulk sensitivity in the range of 10² to 10^3 nm/RIU was reached. The vibrational signals increased of factors ranging between approximately 1.2-5.7, and the SEIRA enhancement was estimated to be in the range of 10^3 to 10^4 for the rectangular nanoantenna arrays.

Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2017-02-20T23:49:40Z No. of bitstreams: 1 ThiagoFernandoGomesDeFreitas_DISSERT.pdf: 3334465 bytes, checksum: 45551c8fb5cbb4b77890be34808aa6b4 (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2017-03-02T23:33:33Z (GMT) No. of bitstreams: 1 ThiagoFernandoGomesDeFreitas_DISSERT.pdf: 3334465 bytes, checksum: 45551c8fb5cbb4b77890be34808aa6b4 (MD5) / Made available in DSpace on 2017-03-02T23:33:33Z (GMT). No. of bitstreams: 1 ThiagoFernandoGomesDeFreitas_DISSERT.pdf: 3334465 bytes, checksum: 45551c8fb5cbb4b77890be34808aa6b4 (MD5) Previous issue date: 2016-05-31 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior (CAPES) / Col?mbolos s?o microartr?podes terrestres que apresentam grande diversidade entre os representantes da fauna ed?fica. Atualmente existem mais de 8 mil esp?cies descritas ao redor do mundo. O Brasil ? considerado um dos pa?ses com uma das maiores diversidades para o grupo, contudo o n?mero de esp?cies descritas no pa?s ainda ? pouco representativo. Atualmente pouco mais de 300 esp?cies foram descritas e a maioria dos registros deriva da regi?o Sudeste. Para a Regi?o Nordeste, especialmente no Bioma Caatinga, o n?mero de estudos ? escasso. Assim, esse trabalho tem como objetivo principal descrever novas esp?cies de Entomobryoidea em duas ?reas de Caatinga do Rio Grande do Norte, especificamente nos munic?pios de Riacho da Cruz e Portalegre, ambos localizados no Oeste Potiguar. As coletas foram realizadas em dois momentos, uma no m?s de novembro de 2013 e outra no m?s junho de 2014. Os esp?cimes foram triados e identificados em laborat?rios e descritos de forma detalhada atrav?s de literatura espec?fica. Foram descritas quatro novas esp?cies, tr?s da fam?lia Entomobryidae: Seira sp. nov. 1, Seira sp. nov. 2, e Lepidocyrtus sp. nov. e uma da fam?lia Paronellidae: Salina sp. nov., Seira sp. nov. 1 foi comparada com tr?s outras esp?cies do g?nero: Seira coroatensis, Seira mendoncea e Seira ritae mostrando diferen?as no n?mero de macrocerdas, diferen?a de espinhos no ?rg?o metatrocanteral e na f?rmula do tri?ngulo labial. Lepidocyrtus sp. nov. comparada com a esp?cie Lepidocyrtus sotoi, apresenta diferen?as na colora??o, f?rmula do tri?ngulo labial, tipos das cerdas prelabrais, n?mero de espinhos no ?rg?o metatrocanteral e altera??o no n?mero de cerdas nos segmentos corporais, Salina sp nov. comparada a Salina maculiflora e Salina colombiana difere na cor, n?mero de espinhos do ?rg?o metatrocanteral e no n?mero de dentes do mucro al?m da vis?vel diferen?a da quetotaxia em todos os segmentos. Seira sp nov. 2, comparada a Seira diamantinae e Seira jiboienses n?o apresenta cerdas na s?rie (a) do mesot?rax, apresenta cinco cerdas intraoculares, sendo uma delas macro, no abd?men IV as cerdas Be2 e Be3 est?o presentes apenas em Seira sp. nov. 2. Este trabalho demonstra a grande diversidade de col?mbolos existentes em ?reas de Caatinga, e al?m do conhecimento de novas esp?cies, pode ajudar a preservar o meio os quais s?o encontrados. / Springtails are land micro arthropods that present huge diversity among the members of edaphic fauna. Nowadays, there are more than 8 thousand species spread around the globe. Brazil is considered one of the countries that has one of the most ranged variety for the group, yet, the number of labelled species in this country is scarcely significant. Currently, the number of labelled species is slightly over 300 and the majority of them derives from the Southwest region. Concerning the Northeast region, specially in the biome Caatinga, the number of studies is scanty. Thus, this paper has as its main goal to describe new species of Entomobryoidea in two Caatinga areas of Rio Grande do Norte, specifically in the municipality of Riacho da Cruz and Portalegre, both located in the west of the city. The collections were made in two disctint moments, the first in November 2013 and the second in June 2014. The specimens were screened and identified in labs and described in details using specific literature. In this piece of work, four new species were described, three from the Entomobryidae family: Seira sp. nov. 1, Seira sp. nov. 2, e Lepidocyrtus sp. nov. and one from the Paronellidae family: Salina sp. nov., Seira sp. nov. 1 was compared to three other species of the same genera: Seira coroatensis, Seira mendoncea e Seira ritae, evidencing differences in the number of macrochaetae, number of spines in the metatrochanteral organ and in the labial triangle setea. Lepidocyrtus sp. nov.compared to the Lepidocyrtus sotoi species, shows differences in colour, labial triangle setea, types of Pre-labral setae, number of spines in the metatrochanteral organ, and change in the number of chaetae in the body segments. Salina sp nov. compared to Salina maculiflora and Salina colombiana evidencing differences in the number of spines of the metatrochanteral organ and in the number of theeth of the mucro and visible difference chaetotaxy in all segments. Seira sp nov. 2, compared to Seira diamantinae and Seira jiboienses does not present chatae in series (a) of mesothorx, it features five intraocular setae, being one macro. In the abdomen IV the chaetae Be2 e Be3 are present only in Seira sp. nov. 2. This paper shows the great diversity of existing collembolans in Caatinga areas, and apart from the knowledge of new species, may aid in the preservation of the environment where they are found.

Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2017-12-12T19:48:28Z No. of bitstreams: 1 NerivaniaNunesGodeiro_TESE.pdf: 42759157 bytes, checksum: 096a840516dd298c1623004a0fa0476d (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2017-12-14T20:25:43Z (GMT) No. of bitstreams: 1 NerivaniaNunesGodeiro_TESE.pdf: 42759157 bytes, checksum: 096a840516dd298c1623004a0fa0476d (MD5) / Made available in DSpace on 2017-12-14T20:25:43Z (GMT). No. of bitstreams: 1 NerivaniaNunesGodeiro_TESE.pdf: 42759157 bytes, checksum: 096a840516dd298c1623004a0fa0476d (MD5) Previous issue date: 2017-09-27 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior (CAPES) / Seirinae ? uma das mais diversas subfam?lias de Collembola, e grande parte dessa diversidade ? devida a Seira Lubbock que possui, aproximadamente, 220 esp?cies reconhecidas. At? o momento, nenhuma filogenia interna foi proposta para o t?xon, o que dificulta a organiza??o do conhecimento para compara??o, descri??o de novas esp?cies e g?neros, al?m da pr?pria compreens?o dos seus padr?es evolutivos. A quetotaxia dorsal ? o principal componente morfol?gico utilizado para distinguir esp?cies, e embora comprovadamente diagn?stico, pode ser vari?vel intraespecificamente. O principal objetivo deste trabalho ? esclarecer as rela??es filogen?ticas entre os Seirinae neotropicais, do ponto de vista molecular e morfol?gico, o que poder? resultar numa melhor organiza??o interna da subfam?lia. Para tanto, foram sequenciadas 27 amostras de diferentes esp?cies de Entomobryidae e uma de Paronellidae. Para as an?lises moleculares, foi extra?do e quantificado o DNA total de um indiv?duo/amostra e bibliotecas foram constru?das e sequenciadas por Next Generation Sequencing utilizando o HiSeq 2000. O genoma mitocondrial (DNAmt) completo das esp?cies foi reconstru?do atrav?s de an?lises de bioinform?tica utilizando duas metodologias: SOAPdenovo_Trans e MIRA/MITOBim. Duas filogenias foram propostas: uma contendo somente os genomas reconstru?dos neste trabalho e outra complementar, onde foram inclu?dos 11 DNAmt de Collembola disponibilizados em bancos de dados online. As filogenias foram feitas por an?lises Bayesianas utilizando os treze genes codificantes proteicos que correspondem a quase totalidade do DNAmt. Os resultados corroboram com a proposta atual que a ordem Poduromorpha ? a mais basal de Collembola; a ordem Symphypleona aparece como grupo-irm?o de Entomobryomorpha, que apresenta clara divis?o em duas superfam?lias, Isotomoidea e Entomobryoidea; o posicionamento dos g?neros Lepidocyrtoides Sch?tt e Lepidosira Sch?tt dentro de Entomobryinae corroboram com a mais recente filogenia publicada; a monofilia de Seirinae e seus grandes grupos internos foi comprovada pela primeira vez por dados moleculares com alto apoio nodal; o g?nero Tyrannoseira Bellini & Zeppelini, recentemente descrito, foi validado filogeneticamente; Lepidocyrtinus B?rner foi al?ado a status de g?nero; e tr?s sinon?mias de esp?cies foram propostas; por fim, algumas caracter?sticas morfol?gicas de Seirinae foram identificadas como diagn?sticas e com sinal filogen?tico, como por exemplo, a quantidade de macroquetas no primeiro segmento abdominal. / Seirinae is one of the most diverse subfamilies of Collembola, and a considerable part of this diversity is comprised by Seira Lubbock, which currently gathers approximately 220 species. So far no internal phylogeny Seirinae was proposed, what leads to difficulties in the establishment of comparative knowledge, description of new taxa, and also the understanding of the evolutionary patterns within this taxon. The dorsal chaetotaxy is the main morphological component utilised to distinguish species, and although undoubtedly diagnostic, it can be variable interspecifically. The main aim of this work is to clarify the phylogenetic relations within the Neotropical Seirinae based on both molecular and morphological data, which might result in a better internal organization of the subfamily. For this aim, 27 samples of different species belonging to Entomobryidae and one of Paronellidae were sequenced. As for molecular analyses genomic DNA of one individual/sample was extracted and quantified and sequencing libraries were built and sequenced using Next-Generation Sequencing on HiSeq 2000. The whole mitochondrial genome (DNAmt) of the species was reconstructed by two methods: SOAPdenovo_Trans and MIRA/MITOBim. Two phylogenies were then proposed: one containing only genomes reconstructed in this study as well as a complementary one, where 11 Collembola DNAmt available in a public database were also included. The phylogenies were generated through Bayesian analyses using the thirteen protein coding genes that almost correspond to the entire DNAmt. The results corroborate the current proposal which claims the order Poduromorpha as the most basal order of Collembola; the order Symphypleona as the sister-group of Entomobryomorpha, which shows clear division into two superfamilies, Isotomoidea and Entomobryoidea; the placement of Lepidocyrtoides Sch?tt and Lepidosira Sch?tt genera inside Entomobryinae corroborates the most recently published phylogeny; the monophyly of the internal groups of Seirinae based on molecular evidence was confirmed for the first time showing high nodal support; Tyrannoseira Bellini & Zeppelini, recently described, was validated phylogenetically; Lepidocyrtinus B?rner was elevated to genus status; and three species synonyms were proposed; finally some morphological characteristics of Seirinae were identified as diagnostic and having phylogenetic signal, for instance, the quantity of macrochaetae on the first abdominal segment.

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