Thesis (M.Sc. Biological Sciences)--University of Waikato, 2007. / Title from PDF cover (viewed April 11, 2008) Includes bibliographical references (p. 245-250)

Zugl.: Bielefeld, Univ., Diss., 2009

Stuttgart, Univ., Diss., 2004.

Universiẗat, Diss., 2003--Frankfurt (Main).

Universiẗat, Diss., 2002--Dortmund.

Mid-Infrared thermal emission sources based on graphene were investigated both experimentally and simulated using the finite element method modelling software package COMSOL. Devices were fabricated by transferring graphene onto various substrates. The thermal emission of few-layer and single graphene on SiO2/Si, under a pulsed square wave drive current, was characterised using spatially resolved thermal emission measurements. It was determined that the devices with single-layer graphene maintained characteristic properties of graphene, while few-layer graphene displayed properties typical of a semi-metal. The effect of thermal management on the emission was investigated by comparing simulations to the emission from these devices and a hexagonal boron nitride encapsulated few-layer graphene device. Limiting the vertical heat dissipation was shown to improve device modulation speed. The emission from the graphene devices was determined to be grey-body in nature. Metamaterial structures, including ring resonators and split ring resonators, were integrated with the encapsulated devices in order to narrow the emission spectra. The emission and reflectance of the devices was characterised using Fourier transform infrared spectroscopy. A tuneable electromagnetically induced transparency like spectral response was observed for devices with metamaterial structures. The resonance peaks were shifted by altering the unit cell parameters. Finally, gallium nitride nano-rod arrays were investigated for the potential to incorporate both spectral control and thermal management into the underlying substrate, in addition to the possibility of the optical generation of graphene plasmons. It was determined that the conventional wet transfer technique was inadequate to transfer the graphene onto the nano-rods. Therefore, a modified transfer technique was utilised, with a significant improvement in the graphene coverage observed. Optical characterisation of the nano-rods using Fourier transform infrared reflectance spectroscopy indicated the excitation of localised surface phonon polaritons, while no evidence was observed in the graphene reflectance spectra of the generation of graphene plasmons.

TELES, Catherine Morais. Caracterização e investigação biológica de complexos de Ir(III) com potencial atividade anticancerígena. 2016. 125 f. Dissertação (Mestrado em Química)-Universidade Federal do Ceará, Fortaleza, 2016. / Submitted by Aline Mendes (alinemendes.ufc@gmail.com) on 2017-05-03T20:04:51Z No. of bitstreams: 1 2016_dis_cmteles.pdf: 5780724 bytes, checksum: e55845e97728a606f266efc4f7b207dd (MD5) / Approved for entry into archive by Jairo Viana (jairo@ufc.br) on 2017-05-18T23:06:08Z (GMT) No. of bitstreams: 1 2016_dis_cmteles.pdf: 5780724 bytes, checksum: e55845e97728a606f266efc4f7b207dd (MD5) / Made available in DSpace on 2017-05-18T23:06:08Z (GMT). No. of bitstreams: 1 2016_dis_cmteles.pdf: 5780724 bytes, checksum: e55845e97728a606f266efc4f7b207dd (MD5) Previous issue date: 2016 / Currently, most metallodrugs used in anticancer treatment are platinum-based complexes. Despite their clinical success, these complexes have restrictions such as, high toxicity causing side effects and resistance to some cancer cell lines. These issues stimulated the search for new metals with different mechanisms of action. In this study, nine (9) organometallic complexes of Ir (III) of the type [Cp * Ir (XY) Z]0/+/+2, where XY = bipyridine, phenanthroline, dipyridophenazine and phenylpyridine and Z = NO2-, indazole and 7-azaindole were synthesised. These compounds were prepared aiming to modulate the cytotoxicity by structural replacements, which were investigated for anti-cancer activity in a screening using three cancer cell lines. Interestingly, three iridium complexes containing distinct chelating ligands did not show any enhancement on anti-cancer activity using as a NO2- ligand. However, for the complex containing dipyridophenazine (dppz) as a chelating agent, it was observed almost double of cytotoxic activity in all cancer cell lines when compared with already active precursor containing chloride. Beside those results, using 7-azaindole as Z ligand, it was observed moderate activity and much higher when compared with inactive precursor containing chloride and also analogous containing indazole. Aiming to understand the mechanism of action for these complexes, it was investigated, preliminarily, DNA as a molecular target. Both complexes containing dppz as chelating ligand showed nuclease activity using plasmid DNA monitored by agarose gel electrophoresis, and also an enhanced activity when subjected to ultraviolet light irradiation (290nm) for 30 minutes. The complex 1-ain had also its interaction with DNA investigated by agarose gel electrophoresis, but it did not show similar differences with indazole or any expressive activity. So, it is possible to expect a different biological target to explain its expressive increase in cytotoxicity. A complex containing 7-azaindole and dppz chelator was synthesized (3-ain) exhibiting nuclease activity, hypochromic effect upon titration with CT-DNA and displacement of ethidium bromide bound to CT-DNA supporting a possible mode of interaction to DNA through intercalation. All together these results support our structural strategy can generate new anti-cancer agents. / Atualmente a maioria dos metalofármacos utilizados no tratamento anticâncer são complexos de platina. Apesar do sucesso clínico, esses complexos possuem restrições como toxicidade alta, causando efeitos colaterais e resistência de algumas linhagens cancerígenas, logo a busca por novos metais a serem utilizados com diferentes mecanismos de ação se faz necessária. Neste trabalho, foram sintetizados 9 complexos organometálicos de Ir(III), do tipo [Cp*Ir(XY)Z]0/+/+2 , em que XY= bipiridina, fenantrolina, dipiridofenazina e fenilpiridina e Z=NO2-, indazol e 7-azaindol. Procurava-se regular a citotoxicidade através das substituições estruturais, para isso, foi realizado um screening anticâncer em 3 linhagens celulares cancerígenas. A substituição do ligante NO2- não se mostrou promissora em combinação com 3 dos quelantes destacados, mas para o complexo contendo o quelante dipiridofenazina (dppz) observou-se quase o dobro de atividade em todas as linhagens cancerígenas quando comparado ao precursor já ativo contendo o ligante cloreto. Uma substituição também promissora foi com o ligante 7-azaindol, apesar de sua semelhança estrutural com o ligante indazol (complexo 1-ain), o composto contendo 7-azaindol e o quelante bipiridina (complexo 3-ain), apresentou atividade moderada e muito superior ao seu precursor inativo contendo cloreto e o análogo contendo indazol. Para se entender o possível mecanismo de ação dos complexos, investigou-se preliminarmente o DNA como alvo molecular. Os dois complexos contendo dppz mostraram atividade nuclease, observados com DNA plasmidial por eletroforese em gel de agarose, e tiveram essa atividade intensificada quando submetidos a irradiação de luz ultravioleta branda (290nm) por 30 minutos. O complexo 3-ain apresentou ainda efeito hipocrômico em titulação com CT-DNA e foi capaz de efetivamente competir com o brometo de etídio em titulação fluorimétrica, sugerindo interação ao DNA através de intercalação. Por outro lado, o complexo 1-ain não apresentou diferenças significativas e nem atividade citotóxica expressiva, logo, espera-se que haja um alvo biológico diferente que justifique o aumento significativo de sua atividade. Desta forma, este trabalho identificou uma rota estratégica para desenvolver novos agentes anticâncer a base de irídio que merecerem posteriores estudos.

No description available.

Made available in DSpace on 2014-06-11T19:30:21Z (GMT). No. of bitstreams: 0 Previous issue date: 2010-07-13Bitstream added on 2014-06-13T19:39:52Z : No. of bitstreams: 1 fonseca_amh_me_sjrp.pdf: 1042737 bytes, checksum: f9dd75259f6eb37c6e7099009f8f986f (MD5) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / O presente trabalho tem como tema central a perífrase verbal ir+infinitivo. Sob o ponto de vista da Gramaticalização, tratamos da formação da perífrase e de sua multifuncionalidade no Português Brasileiro, mais especificamente na variedade falada no interior do Estado de São Paulo. As amostras de fala integram o banco de dados Iboruna. Além da função de futuridade, a perífrase expressa também funções aspectuais, modais e de marcador discursivo, multifuncionalidade decorrente de diferentes estágios de sua gramaticalização. A partir das funções identificadas, relacionamos os graus de gramaticalidade da perífrase com a escala universal de gramaticalização das categorias verbais flexionais do complexo TAM (Tempo, Aspecto, Modo/Modalidade), comprovando a hipótese de que a escala de gramaticalização de ir+infinitivo obedece à ordem “universal” dos morfemas verbais flexionais como postulado em Bybee (1985). Sob o enfoque da Sociolinguística, procedemos ao tratamento variável da expressão de futururidade codificada por [IRPRESENTE INDICATIVO + Infinitivo] vs. [Futuro do Presente], no caso de Futuro do Presente, e por [IRPRETÉRITO IMPERFEITO + Infinitivo] vs. [Futuro do Pretérito], no caso de Futuro do Pretérito. Enquanto a expressão de Futuro do Presente não constitui regra variável na comunidade de fala investigada, visto que a mudança já se instaurou em favor da variante analítica, a expressão de Futuro do Pretérito na forma analítica é condicionada pelos seguintes fatores: estatuto sintático da oração (orações subordinadas), paradigma verbal do verbo principal (verbos regulares), tipo de estado de coisas (estado), tipo de texto (narrativo) e idade do informante (faixa etária mais jovem). Ao final, consideramos que a principal contribuição do trabalho foi a de mostrar o êxito da abordagem de um mesmo fenômeno na interface... / This study focuses on the ir+infinitive verbal periphrasis. From the aspect of Grammaticalization, this study approaches the formation of the periphrasis and its multifunctionality in Brazilian Portuguese language, especially in the variety used in the interior of São Paulo State. The samples of speech integrate the Iboruna database. Besides the function of futurity, the periphrasis also expresses aspectual and modal functions, and acts as discourse marker. This multifunctionality derives from different stages of its grammaticalization. Based on the functions identified, we have related the grammaticality degrees of the periphrasis to the universal scale of grammaticalization of flexional verbal categories of the TAM complex (Time, Aspect, Mode/Modality), proving the hypothesis that the grammaticalization scale of ir+infinitive follows the “universal” order of flexional verbal morphemes, as postulated in Bybee (1985). Under the focus of Sociolinguistics, we proceed to the variable treatment of the expression of futurity encoded by [IRPRESENT INDICATIVE + Infinitive] vs. [Future of Present], in the case of the Future of Present, and by [IRIMPERFECT PRETERITE + Infinitive] vs. [Future of Preterite], in the case of the Future of Preterite. While the expression of the Future of Present does not constitute a variable rule in the speech community investigated – due to the fact that the change has already been established in favor of the analytical variant –, the expression of the Future of Preterite is conditioned by the following factors: syntactic statute of the clause (subordinate clause), verbal paradigm of the main verb (regular verbs), type of state of things (state), type of text (narrative) and age of the informer (youngest age-group). Finally, it is possible to consider that the main contribution of this study was to show the success of approaching the same phenomenon... (Complete abstract click electronic access below)

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.