Made available in DSpace on 2014-06-11T19:35:05Z (GMT). No. of bitstreams: 0 Previous issue date: 2000Bitstream added on 2014-06-13T19:44:55Z : No. of bitstreams: 1 godoi_rhm_dr_araiq.pdf: 3270573 bytes, checksum: 3559f7c3543330be1257e14395d9f52a (MD5) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / Partículas magnéticas de ferrita de Ítrio (YIG) foram preparadas através da heterocoagulação da sílica sobre a ferrita de ítrio. A ferrita de ítrio foi obtida através do processo de nucleação homogênea, controlando a rota química a partir da hidrólise de cátions em meio ácido. A heterocoagulação foi induzida pela hidrólise do tetraetilortosilicato (TEOS) em diferentes meios de dispersão da ferrita de ítrio. Os produtos dispersos foram calcinados e caracterizados por magnometria de amostra vibrante, espectroscopia fotoeletrônica de raios X, microscopias eletrônicas de varredura e de transmissão, difração de elétrons, análise térmica diferencial, difratometria de raios X e mobilidade eletroforética. A camada de sílica que recobre a ferrita de ítrio foi identificada por microscopia eletrônica de transmissão. Difração de elétrons permitiu distinguir a fase policristalina da ferrita de ítrio e a sílica. A ausência dos picos de Fe e Y no espectro de XPS das partículas confirmam que o processo de heterocoagulação foi efetivo. Comparando as propriedades magnéticas da ferrita de ítrio e do sistema sílica/ferrita de ítrio infere-se que as propriedades de magnetização de saturação (Ms) e de campo coercivo (Hc) variaram em função da camada de sílica. / Yttrium iron garnet (YIG) particles were coated with silica for control of their synthesis, improving the performance of system and stabilization of magnetic properties. Well-defined magnet particles were prepared by heterocoagulating silica on yttrium iron garnet. Yttrium iron garnet was obtained by homogeneous nucleation process, controlling the chemical routes from cation hydrolysis in acid medium. The heterocoagulation was induced by hydrolysis of tetraethylorthosilicate (TEOS) in appropriate yttrium iron garnet dispersion medium. Dispersed calcinated product was and characterized by vibrating sample magnetometry, X-ray photoemission spectroscopy, transmission and scanning electron microscopies, small area electron diffraction, differential thermal analysis, X-ray diffractometry and electrophoretic mobility. The pure systems YIG and Silica particles dispersions show appropriated physical-chemistry characteristics to be heterocoagulated. The shell of silica on YIG was identified by transmission electron microscopy and small area electron diffraction allowed to distinguish both silica and polycrystalline YIG phases. The absence of Fe and Y peaks on the particle surface XPS measurements confirmed that the heterocoagulation process was carried out by X-ray photoemission spectroscopy Comparing the magnetic measures of the YIG and silica on YIG samples, the magnetic properties of Ms were reduced and of Hc varied in function of the cover layer.

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Made available in DSpace on 2014-10-09T12:26:02Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:06:50Z (GMT). No. of bitstreams: 1 00378.pdf: 987505 bytes, checksum: b6587927b6c5975dc6119eb53714b845 (MD5) / Dissertacao (Mestrado) / IEA/D / Instituto de Energia Atomica - IEA

Orientador: Celso Dario Ramos / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Ciências Médicas / Made available in DSpace on 2018-08-26T18:27:04Z (GMT). No. of bitstreams: 1 Takahashi_MariaEmiliaSeren_M.pdf: 16141939 bytes, checksum: 42dea31b2ec345da45284f3ac4086cfc (MD5) Previous issue date: 2015 / Resumo: Contexto: Apesar do importante potencial dos cálculos dosimétricos para uso clínico em radiosinoviortese (RSV), há poucos dados na literatura sobre este assunto. Neste trabalho, é proposta uma metodologia para dosimetria beta paciente-específica utilizando imagens SPECT/CT para avaliar a dose absorvida por RSV em articulações tratadas com hidroxiapatita marcada com samário-153 (HA-153Sm) e hidroxiapatita marcada com ítrio-90 (HA-90Y). Metodologia: Uma análise voxel-por-voxel foi realizada para construir um mapa de dose absorvida tridimensional para três pacientes tratados com HA-90Y (185MBq) ou HA-153Sm (740MBq). Uma equação genérica de dose absorvida foi utilizada para calcular a dose absorvida no voxel, a partir da atividade intra-voxel obtida da quantificação da imagem SPECT e a sua massa correspondente obtida a partir da imagem CT. Considerando o tamanho do voxel (7.79mmX7.79mmX7.79mm), a energia média e o alcance terapêutico das partículas beta emitidas do 90Y e 153Sm, é assumido que a dose em cada voxel não é afetada pela atividade dos voxels vizinhos. Dados sobre a razão de dose entre HA-90Y e HA-153Sm foram comparados. Resultados: Foram obtidas distribuição espacial da dose absorvida, dose absorvida total e dose absorvida por atividade injetada para cada paciente. A dose absorvida relativa entre HA-90Y e HA- 153Sm foi cerca de 5.5:1. Conclusão: Dosimetria paciente-específica em RSV pode ser uma poderosa ferramenta, especialmente em distribuições heterogêneas de radiotraçadores intra-articulares, quando doses terapêuticas complementares podem ser necessárias. Usando esta metodologia, foi possível demonstrar que podem ser obtidos efeitos terapêuticos comparáveis entre as RSVs realizadas com HA-90Y e HA-153Sm se for utilizada uma atividade cerca 5.5 vezes maior de HA-153Sm / Abstract: Background: Despite the potential clinical importance of dosimetric calculations in radiosynovectomy (RSV), there are very few data in the literature about this topic. In this study, we propose a patient-specific methodology for beta dosimetry using SPECT/CT images to evaluate the absorbed dose of RSV in human joints treated with HA-90Y and HA-153Sm. Methods: A voxel-by-voxel analysis was performed to build a 3D absorbed dose map for three patients treated with HA-90Y (185MBq) or HA-153Sm (740MBq). A generic absorbed dose equation was used to calculate the voxel dose, supported by the voxel activity obtained from quantified SPECT image and the corresponding voxel mass obtained from CT image. Considering the voxel size (7.79mmX7.79mmX7.79mm), the average energy and the therapeutic range of emitted beta particles from 90Y and 153Sm, we assumed that the dose in each voxel is not affected by the activity of neighboring voxels. Data about ratio of absorbed dose between HA-90Y and HA-153Sm were compared. Results: Spatial distribution of absorbed dose, total absorbed dose and absorbed dose per injected activity were obtained for each patient. The calculated relative absorbed dose between HA-90Y to HA-153Sm was about 5.5:1. Conclusions: Patient-specific dosimetry in RSV can be a powerful tool, especially in heterogeneous intra-articular distributions of radiotracer when additional therapeutic doses can be administered. Using this methodology we estimated that it is possible to achieve comparable therapeutic effects for RSV using HA-90Y if one uses activities about 5.5 times greater of HA-153Sm / Mestrado / Clinica Medica / Mestra em Clínica Médica

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Les hétérocycles azotés chiraux représentent une classe importante de composés biologiquement actifs. L’hydroamination asymétrique intramoléculaire correspond parfaitement au concept d’économie d’atomes et permet l’accès direct à la formation de nouvelles liaisons carbone-azote. Le développement de catalyseurs pour la formation de pyrrolidines et piperidines reste cependant une tâche importante. Le thème de cette thèse est l’étude de nouveaux complexes chiraux binaphthylamide d’yttrium facilement accessibles et leur application pour promouvoir la réaction d’hydroamination/cyclisation des amines primaires liées à des alcènes stériquement encombrés.Des complexes chiraux binaphthylamidure alkyl ate d’yttrium ont été développés. Ces systèmes catalytiques ont été préparés in situ par une réaction simple stœchiométrique en présence d’un précurseur d’yttrium [Li(THF)4][Y(CH2SiMe3)4] connu et d’une variété de ligands chiraux binaphthyldiamine substitués. Les complexes chiraux hétéroleptiques obtenus se sont révélés actifs et énantiosélectifs pour la réaction d’hydroamination asymétrique intramoléculaire des aminoalcènes 1,2-disubstitués conduisant à la formation d’hétérocycles azotés avec cinq et six châinons. Les catalyseurs d’yttrium préparés à partir du ligand (R)-N-anthrylmethyl-binaphthylamine H2L13 et des ligands (R)-benzyl N-para-substitués H2L4 or H2L6 se sont révélés les plus énantiosélectifs à 70-110°C pour la réaction d’hydroamination/cyclisation des aminoalcènes encombrés. Un excès énantiomérique de 77% a été obtenu comme valeur la plus élevée décrite jusqu’à présent pour l’hydroamination asymétrique intramoléculaire des amines comportant des alcènes 1,2-disubstitués. Les premiers exemples de la réaction d’hydroamination intramoléculaire asymétrique des aminoalcènes 1,1,2-trisubstitués ont été rapportés. Les complexes ate alkyl d’yttrium ont fourni les produits hétérocycliques avec des centres quaternaires énantiomériquement enrichis dans des conditions réactionelles plus sévères que la cyclisation des aminoalcènes 1,2-disubstitués et avec des énantiosélectivités prometteuses atteignant 55%. Les complexes alkyl d’yttrium contenant une molécule de chlorure de lithium [{(R)-C20H12(NSiMe3)2}Y{CH2SiMe3}{LiCl(THF)2}] and [{(R)-C20H12(NC5H9)2}Y{CH2SiMe3}{LiCl(THF)2}] ont été préparés et comparés aux mêmes complexes sans LiCl. Ils se sont révélés être des catalyseurs efficaces pour la réaction d’hydroamination intramoléculaire des aminoalcènes terminaux. / Chiral nitrogen-containing heterocycles represent an important class of biologically active compounds. The asymmetric intramolecular hydroamination perfectly matches the concept of sustainable chemistry and allows the formation of new nitrogen-carbon bonds in an ideal atom efficiency and economy, starting from non activated substrates. The development of catalysts for formation of enantioenriched pyrrolidines and piperidines derivatives remains however a challenging task. The topic of this dissertation is the study of new easily accessible chiral yttrium binaphthylamide complexes and their application for promoting the hydroamination/cyclisation of primary amines tethered to sterically demanding alkenes. Chiral binaphthylamido alkyl ate yttrium complexes have been investigated. These catalytic systems have been prepared by a facile in situ stoichiometric reaction of a well-known yttrium precursor [Li(THF)4][Y(CH2SiMe3)4] with a variety of chiral substituted (R)-binaphthylamine ligands. These chiral heteroleptic complexes are shown to be efficient catalysts for the enantioselective intramolecular hydroamination of 1,2-disubstituted aminoalkenes leading to the formation of five and six-membered N-heterocycles. Yttrium catalysts prepared from (R)-N-anthrylmethyl-binaphthylamine ligand H2L13 and (R)-N-para-substituted benzyl ligands H2L4 or H2L6 proved to be the most enantioselective catalysts at 70-110°C for the hydroamination/cyclisation of challenging aminoalkenes. An enantiomeric excess value of 77 % was indeed disclosed as the highest value reported so far for the asymmetric intramolecular hydroamination of amines tethered to 1,2-disubstituted alkenes. The first examples of asymmetric intramolecular hydroamination of 1,1,2-tri-substituted aminoalkenes have been reported. The alkyl ate yttrium complexes produced the heterocyclic compounds with enantioenriched quaternary centres under harsher reaction conditions than the cyclisation of the corresponding 1,2-disubstituted alkenes, and with promising enantioselectivities of up to 55 %.The neutral alkyl yttrium complexes containing one molecule of lithium chloride [{(R)-C20H12(NSiMe3)2}Y{CH2SiMe3}{LiCl(THF)2}] and [{(R)-C20H12(NC5H9)2}Y{CH2SiMe3}{LiCl(THF)2}] have been prepared and compared with the same complexes lacking LiCl. They have been revealed as efficient catalysts for intramolecular hydroamination of terminal aminoalkenes.

In this project self-supporting foils with focus on the element yttriumhave been fabricated by means of evaporation and magnetron sputtering.The goal was to see if it was possible to make photochromic selfsupportingyttrium foils. Multiple self-supporting foils were made andsome had suitable properties to be further investigated. The first foilof interest was a plain carbon foil, the second was yttrium layered ontop of a carbon foil, the third was a yttrium-only foil and the fourthwas a yttrium oxyhydride foil. The foils were then subsequentlycharacterized with a newly developed Medium Energy Ion Scattering -Elastic Recoil Detection Analysis (MEIS - ERDA) technique. Thistechnique measures energy loss and recoils (kicked out atoms) of heavyions passing through the self-supporting foils. The measurements weremade with three ion projectile energies, 250, 300 and 320keV. Theprojectiles sent were argon ions. It was noted that the yttriumoxyhydride foil had more hydrogen and oxygen than the yttrium foil. Withoptical measurements it was also possible to confirm that the yttriumoxyhydride foil had photochromic properties. With the knowledge of theparameters used to fabricate these foils, the conclusion is that furtherresearch on self-supporting yttrium oxyhydride is encouraged.

This thesis describes the synthesis of yttrium oxide nanoparticles in an AOT/isooctane reverse micelle solution. Two synthetic methods are compared. First is the precipitation reaction between yttrium nitrate and ammonia, second is the hydrolysis of yttrium isopropoxide. The effects of annealing of the resulting the yttrium oxide nanoparticles are also described. The nitrate method produced network-like aggregates of yttrium oxide nanoparticles ranging from 10 nm to 40 nm in diameter. Reaction conditions, including the water/AOT ratio (1 to 15), the nitrate concentration (0.02 M to 1.0 M), the ammonia concentration (2 M to 14.8 M), the AOT concentration (0.1 M and 0.5 M), the aging time (1 h to 5 d), and the washing method, were varied to investigate their influence on nanoparticle formation. The optimized synthetic conditions were: a water/AOT ratio of 7.5, [NO₃⁻] = 0.5 M, [NH₃] = 2 M, and [AOT] = 0.1 M. The as-prepared yttrium oxide nanoparticles had highly distorted structures related to the cubic Y2O3 phase. Annealing improved the crystallinity of the as-prepared nanoparticle products and led to larger particles. As annealing temperatures increased, the yttrium oxide nanoparticles gradually evolved into the cubic Y₂O₃ phase. However, an unknown intermediate phase was also observed during the annealing process, which disappeared when the annealing temperature was sufficiently high and the annealing time was long enough (>1000 °C and 4 h). As-prepared products from the isopropoxide hydrolysis also contained network-like nanoparticle aggregates. Particle sizes ranged from 10 nm to 20 nm. Some experimental conditions were varied; they were the water/AOT ratio (10 to 40), the isopropoxide concentration (0.0001 M to 0.003 M), the aqueous phase pH (7.0 and 12.0), the aging temperature (room temperature, approximately 25 °C, and refluxing temperature, approximately, 100 °C), and the aging time (1 h to 5 d). Transmission Electronic Micrographs showed that products of desirable morphology could be produced in a much wider range of experimental conditions by this method compared to those produced by nitrate hydrolysis. / Master of Science