758 resultados para isótopos estáveis


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This paper aims the preparation, characterization and study of luminescence, particularly as for the cerium ion action as activator or sensitizer, in diphenylphosphinate of lanthanum compounds trivalent ions cerium-, europium-, and/or terbium-doped. The following compounds were prepared and studied: i) La1-(x+y)CexEuy(DFF)3; ii) La1-(x+y)CexTby(DFF)3; iii) La1-(x+y+z)CexEuyTbz(DFF)3, with x = 10%, y = 5% e z = 5%. The diphenylphosphinate of lanthanum, Ln[(Ph2)PO2]3, are complexes obtained by the mixture of lanthanides chlorides with diphenylphosphinic acid, ethanol medium. These compounds make white powders, crystalline, insoluble in normal temperature and pressure, and are chemically and thermally stable. When doping with Ce3+, Eu3+ and/or Tb3+, the compounds present characteristic luminescence. Luminescent materials are made of a host matrix incorporated with few amounts of ions called activators, which are able to present luminescence after being excited by UV light or high energy radiation, and sensitizer ions, which have the role of absorbing excitation energy and transfer it to the activator, for it to emit luminescence radiation. The infrared vibrational spectroscopy indicates that the coordination occurs by the oxygens of phosphorile group with ΔνPO of about 40 cm-1 compared to the free ligand. The X Ray difractograms of compounds Eu- and/or Tb-doped are similar, but they present profile of diffraction different observed by Stucchi and col. In previous papers, indicated an influence of Ce in the crystalline phase formation of these matrices. In luminescence spectrums, the excitation that can be made by the levels of ligand in 273 nm, or cerium ion in area between 300 and 400 nm were observed. In the emission spectrum, with excitation in 273 nm, is possible to observe the emission of Ce3+ below 400 nm and the Eu3+ in 592, 611 and 617 nm, and the...as a sensitizer to.

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This work deals with the synthesis, spectroscopic characterization of mono and polynuclear Pd(II) compounds obtained from the reaction between [PdCl2(MeCN)2] precursor and imidazolidine-2-thione (L1) and benzimidazoline-2-thione (L2). The interaction between [PdCl2(MeCN)2] and imidazolidine-2-thione, in the 1:2 molar ratio, using MeOH as solvent, yielded compound [Pd2Cl4(L1)4]Cl2 (1) whereas the complex [Pd2Br4(L1)4]Br2 (2) was obtained from the reaction between 1 and Br- ions. Binuclear compounds of general formulae [Pd2(L2)4]X23/2 MeOH {X= Cl-(3), Br-(4)} were synthesized using benzimidazoline-2-thione as ligand, employing the same procedure used in the synthesis of 1 and 2, respectively. The new complexes 1-4 are crystalline, air stable and soluble in methanol and dmso. The compounds were characterized by elemental analysis, IR spectroscopy, ESI/MS mass spectrometry and thermogravimetry. Coordination of the ligands L1 and L2 via sulphur atom was evidenced by the shift of the CS band (~499 cm-1, 1 and 2; ~620 cm-1, 3 and 4) to lower frequencies in comparison with those found in the free ligands (510 cm-1, L1; 660 cm-1, L2), indicating the weakening of the CS bom after coordination. ESI/EM mass spectra (positive mode) of the complexes 1-4 allowed atribute the molecular formulae [Pd2X4(L1)4]X2 {X= Cl-(1), Br-(2)} and [Pd2(L2)4]X2 {X= Cl-(3), Br-(4)} by the appearance of the peaks at m/z 794,61 [(1) + MeOH]+, m/z 836,77 [(2) - 2H - L1]+, m/z 810 [(3) - 2Cl]+, m/z 810 [(4) - 2Br]+. The TG-DTA curves showed that the complexes 1 and 2 are thermally stable up to 212 and 169º C, respectively, and further decompose to metallic palladium at 527º C (1, obt. 28,46 %; calcd. 27,88%) and 895º C (2, obt. 22,85 %; calcd. 22,62%). Compounds 3 and 4 exhibited an initial mass loss of ~5% between 25 -146º C related to the release of metanol molecules. The complexes 3...Fujimura Leite.

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Pós-graduação em Física - IFT

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The association between emotional stress and intense bruxism has as consequence the Temporomandibular Disorder (TMD), which is an increasingly apparent problem at the dental clinic, requiring judicious means of diagnosis and especially treatment.. Several factors, of equivalent importance, may be related to the DTM, one of them is the loss of vertical dimension of occlusion (VDO), and parafunctional habits and also the loss of stable contacts between the posterior teeth or lack thereof, which generates an increase functional anterior teeth for excessive wear or buccal and consequent.. This paper proposes using a clinical case, to present and discuss the steps for clinical diagnosis, planning and execution of oral rehabilitation with Fixed Partial Denture for restoring vertical dimension of occlusion in a patient with severe parafunction.. Oral rehabilitation of these patients should be carefully planned, respecting the functional and aesthetic aspects.. The parafunction control by monitoring the Temporomandibular Disorder is essential to the longitudinal prediction of rehabilitation performed in these types of rehabilitative treatment.

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Are called panfacial fractures when the upper, middle and lower facial thirds present fractures concurrently. In clinical practice, came to imply the involvement of two facial thirds. Panfacial fractures are usually accompanied by other systemic lesions that impair the patient's life and therefore require primary treatment. Almost invariably are associated with damage to soft tissues and severe losses of bone structures which may lead to severe facial deformations and malocclusions. The panfacial fractures treatment is complex because often there isn’t a stable bone structure to guide the reduction of various fractures. Several orders of treatment have been proposed, but they are variations of the two classical approaches "bottom to top and inside-out" and "top to bottom and out-inside". The aim of this paper is to discuss the principles of management and panfacial fractures treatment, emphasizing the sequence of fracture reduction and highlighting its indications, advantages and disadvantages, through literature review and reports of surgical clinic cases. We conclude that the exact sequence of fracture reduction is not as important as developing a treatment plan that allows accurate positioning of the fractured segments.

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Introdução: As exigências nutricionais para o paciente transplantado são conhecidas, mas há poucas evidências sobre o consumo alimentar e o seu efeito no estado nutricional. O objetivo deste estudo é avaliar o efeito do transplante de células-tronco hematopoéticas (TCTH) no estado nutricional de pacientes orientados e monitorados quanto ao consumo alimentar durante os primeiros 100 dias do procedimento. Método: Participaram do estudos 27 indivíduos que realizaram TCTH, com idade entre 20 e 60 anos, 13 mulheres e 14 homens, índice de massa corporal médio de 27+/- 5kg/m². Os pacientes receberam orientações nutricionais individualizadas quanto ao consumo de alimentos. Nos momentos pré-TCTH, D+30, D_60 e D+100 (D+n = dias decorridos do TCTH) foram monitorados o consumo de alimentos, a partir de recordatório do consumo de 24 horas e o estado nutricional a partir dos indicadores antropométricos. Resultados: Após 100 dias do transplante, foi constatado que os 27 indivíduos analisados mantiveram estáveis o consumo alimentar e o estado nutricional. Conclusão: A orientação nutricional proporcionou a preservação do estado nutricional após o TCTH, a qual se deu à custa de incremento no consumo de energia e nutrientes oriundos de suplementos alimentares e também de alimentos não tão saudáveis.

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Conselho Nacional de Desevolvimento Científico e Tecnológico (CNPq)

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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The horse’s blood pressure is susceptible to changes induced by volatile anesthetics. Because of that, the use of anesthesic techniques which keep stable the horse´s blood pressure is essencial. Ketamine is an important induction and maintenance anesthetic agent used in the horse anesthesia practice mainly to improve the blood pressure. S(+)-ketamine provides the same effects on the blood pressure, with greater analgesic results and less side effects than the normal ketamine. Although some studies have been conducted with ketamine continuous rate infusion during the halothane anesthetized horses, the S(+)-ketamine has not been evaluated yet. Considering the increased use of ketamine, it is important to evaluate its cardiovascular and respiratory effects in halothane anesthetized horses. To conclude, S(+)-ketamine 0.01mg/kg/min. continuous rate infusion did not induce additive cardiovascular and respiratory depression in halothane anesthetized horses.

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Pós-graduação em Agronomia (Ciência do Solo) - FCAV

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)