897 resultados para sodium and lithium niobate
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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Pós-graduação em Engenharia Elétrica - FEIS
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Pós-graduação em Engenharia Elétrica - FEIS
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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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The performance of advanced electronic ceramics is directly related to the synthesis route employed. Sol-gel methods are widely used for this purpose. However, the physicochemical intermediate steps are still not well understood. Better understanding and control of these processes can improve the final quality of samples. In this work, we studied theoretically the formation of metal complexes between citric acid and lithium or barium metal cations with different citric acid/metal proportions, using Density Functional Theory electronic structure calculations. Infrared and Raman scattering spectra were simulated for the more stable geometric configurations. Using this methodology, we identified some features of complexes formed in the synthesis process. Our results show that the complexes can be distinguished by changes in the bands assigned to C=O, COH-, and COO- group vibrations. An estimate of the most stable complexes is made based on total energy.
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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Aims: The study evaluated the influence of light curing units and immersionmedia on superficial morphology and chemistry of the nanofilled composite resin Supreme XT (3M)through the EDX analysis and SEM evaluation. Light curing units with different power densitiesand mode of application used were XL 3000 (480 mW/cm2), Jet Lite 4000 Plus (1230mW/cm2), andUltralume Led 5 (790 mW/cm2) and immersion media were artificial saliva, Coke1, tea and coffee,totaling 12 experimental groups. Specimens (10 mm 3 2 mm) were immersed in each respectivesolution for 5 min, three times a day, during 60 days and stored in artificial saliva at 378C 6 18Cbetween immersion periods. Topography and chemical analysis was qualitative. Findings: Groupsimmersed in artificial saliva, showed homogeneous degradation of matrix and deposition of calciumat the material surface. Regarding coffee, there was a reasonable chemical degradation with loss ofload particles and deposition of ions. For tea, superficial degradation occurred in specific areaswith deposition of calcium, carbon, potassium and phosphorus. For Coke1, excessive matrix degra-dation and loss of load particles with deposition of calcium, sodium, and potassium. Conclusion:Light curing units did not influence the superficial morphology of composite resin tested, but theimmersion beverages did. Coke1affected material’s surface more than did the other tested drinks.Microsc. Res. Tech. 73:176–181, 2010.
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A study was conducted to evaluate the s of dietary inorganic and organic trace minerals in two levels of supplementation regarding performance, diarrhea occurrence, hematological parameters, fecal mineral excretion and mineral retention in metacarpals and liver of weanling pigs. Seventy piglets weaned at 21 days of age with an average initial body weight of 6.70 ± 0.38 kg were allotted in five treatments: control diet (no added trace mineral premix); 50% ITMP (control diet with inorganic trace mineral premix supplying only 50% of trace mineral requirements); 50% OTMP (control diet with organic trace mineral premix supplying only 50% of trace mineral requirements); 100% ITMP (control diet with inorganic trace mineral premix supplying 100% of trace mineral requirements); and 100% OTMP (control diet with organic trace mineral premix supplying 100% of trace mineral requirements). Feed intake and daily weight gain were not affected by treatments, however, piglets supplemented by trace minerals presented better gain:feed ratio. No differences were observed at calcium, phosphorus, potassium, magnesium, sodium and sulfur excreted in feces per kilogram of feed intake. Treatments did not affect calcium, phosphorus, magnesium, sulfur and iron content in metacarpals. Trace mineral supplementation, regardless of level and source, improved the performance of piglets.
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We present here some results of our research related to the optoelectronics and photonics and show all the experimental setups used. Starting with a discussion on the importance of the waves, we demonstrate our achievements based on employment of acoustic, optical, and microwaves and their technological use. The results concern the acousto-optic and electro-optic effects. The generalized analysis of the electro-optic effect reveals a new high induced birefringence in lithium niobate. A patented optical fiber microphone is presented, and its applications to the measurements of acoustic wave velocity in gases and in the laser ultrasound non-destructive evaluation system are discussed. Finally, the generation of microwaves by an optical method with substantial cost reduction is presented.
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To determine whether central α1 and α2-adrenergic mechanisms are involved in urinary sodium and potassium excretion and urine volume induced by angiotensin II (ANGII), these renal parameters were measured in volume-expanded Holtzman rats with cannulas implanted into lateral ventricle (LV) and lateral hypothalamus (LH). The injection of ANGII into LV in rats with volume expansion reduced the sodium, potassium and urine excretion in comparison to the control injections of isotonic saline, whereas prazosin (α1 antagonist) potentiated these effects. Clonidine (α2 agonist) and yohimbine (α2 antagonist) injected into LH previous to injection of ANGII into LV also abolished the inhibitory effect of ANGII. These results suggest that the discharge of central alpha-adrenergic receptors has dual inhibitory and excitatory effect on antinatriuretic, antikaliuretic and antidiuretic effect induced by central ANGII in volume-expanded rats. © 1995.
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A espécie vegetal, Petroselinum sativum Hoff, conhecida como salsa, é amplamente utilizada na medicina popular brasileira como diurético. O objetivo desse estudo é verificar se o uso brasileiro do extrato aquoso da salsa tem efeitos semelhantes com investigações que mostram o efeito diurético da P. sativum em ratos. MÉTODOS: 19 Ratos foram anestesiados e canulamos a traquéia, artéria carótida esquerda (para a medição da pressão arterial) e bexiga urinária (para coletar urina). Depois de 40 minutos para adaptação das condições cirúrgicas, ratos anestesiados foram administrados de acordo com seus grupos: controle (CON), administração oral com 1.0 mL de água filtrada, e grupo tratado (AE), administração oral com extrato aquoso de sementes de salsa 20% (AE). Urina foi coletada três vezes (de 30 em 30 minutos) e então esse material foi utilizado para determinações de sódio e potássio, para avaliar a quantidade excretada desses íons. Pressão arterial foi medida pelo manômetro de mercúrio por 9 vezes. Todos os dados foram estatisticamente avaliados. RESULTADOS E CONCLUSÃO: nos parâmetros anestesiados, o grupo CON não mostrou nenhuma diferença; mas o grupo AE mostrou um aumento do fluxo urinário e da quantidade excretada de sódio e potássio, e também uma diminuição da pressão arterial. Todos os parâmetros apresentaram essas modificações após 30 minutos de administração do AE (p<0,05). Esses resultados mostram que o tratamento com o AE leva a efeitos natriurético e hipotensor em ratos Wistar anestesiados, confirmando o uso da população brasileira dessa erva como diurético.
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The deactivation of the inhibitory mechanisms with injections of moxonidine (alpha(2)-adrenoceptor/imidazoline receptor agonist) into the lateral parabrachial nucleus (LPBN) increases hypertonic NaCl intake by intra- or extracellular dehydrated rats. In the present study, we investigated the changes in the urinary sodium and volume, sodium balance, and plasma vasopressin and oxytocin in rats treated with intragastric (i.g.) 2 M NaCl load (2 ml/rat) combined with injections of moxonidine into the LPBN. Male Holtzman rats (n=5-12/group) with stainless steel cannulas implanted bilaterally into LPBN were used. Bilateral injections of moxonidine (0.5 nmol/0.2 mu l) into the LPBN decreased i.g. 2 M NaCIinduced diuresis (4.6 +/- 0.7 vs. vehicle: 7.4 +/- 0.6 ml/120 min) and natriuresis (1.65 +/- 0.29 vs. vehicle: 2.53 +/- 0.17 mEq/120 min), whereas the previous injection of the alpha(2)-adrenoceptor antagonist RX 821002 (10 nmol/0.2 mu l) into the LPBN abolished the effects of moxonidline. Moxonidine injected into the LPBN reduced i.g. 2 M NaCl-induced increase in plasma oxytocin and vasopressin (14.6 +/- 2.8 and 2.2 +/- 0.3 vs. vehicle: 25.7 +/- 7 and 4.3 +/- 0.7 pg/ml, respectively). Moxonidine injected into the LPBN combined with i.g. 2 M NaCl also increased 0.3 M NaCl intake (7.5 +/- 1.7 vs. vehicle: 0.5 +/- 0.2 mEq/2 h) and produced positive sodium balance (2.3 +/- 1.4 vs. vehicle: -1.2 +/- 0.4 mEq/2 h) in rats that had access to water and NaCl. The present results show that LPBN alpha(2)-adrenoceptor activation reduces renal and hormonal responses to intracellular dehydration and increases sodium and water intake, which facilitates sodium retention and body fluid volume expansion. (C) 2012 IBRO. Published by Elsevier Ltd. All rights reserved.
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Objective. To describe individual attitudes, knowledge, and behavior regarding salt intake, its dietary sources, and current food-labeling practices related to salt and sodium in five sentinel countries of the Americas. Methods. A convenience sample of 1 992 adults (>= 18 years old) from Argentina, Canada, Chile, Costa Rica, and Ecuador (approximately 400 from each country) was obtained between September 2010 and February 2011. Data collection was conducted in shopping malls or major commercial areas using a questionnaire containing 33 questions. Descriptive estimates are presented for the total sample and stratified by country and sociodemographic characteristics of the studied population. Results. Almost 90% of participants associated excess intake of salt with the occurrence of adverse health conditions, more than 60% indicated they were trying to reduce their current intake of salt, and more than 30% believed reducing dietary salt to be of high importance. Only 26% of participants claimed to know the existence of a recommended maximum value of salt or sodium intake and 47% of them stated they knew the content of salt in food items. More than 80% of participants said that they would like food labeling to indicate high, medium, and low levels of salt or sodium and would like to see a clear warning label on packages of foods high in salt. Conclusions. Additional effort is required to increase consumers' knowledge about the existence of a maximum limit for intake and to improve their capacity to accurately monitor and reduce their personal salt consumption.
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Inoue BH, dos Santos L, Pessoa TD, Antonio EL, Pacheco BPM, Savignano FA, Carraro-Lacroix LR, Tucci PJF, Malnic G, Girardi ACC. Increased NHE3 abundance and transport activity in renal proximal tubule of rats with heart failure. Am J Physiol Regul Integr Comp Physiol 302: R166-R174, 2012. First published October 26, 2011; doi:10.1152/ajpregu.00127.2011.-Heart failure (HF) is associated with a reduced effective circulating volume that drives sodium and water retention and extracellular volume expansion. We therefore hypothesized that Na(+)/H(+) exchanger isoform 3 (NHE3), the major apical transcellular pathway for sodium reabsorption in the proximal tubule, is upregulated in an experimental model of HF. HF was induced in male rats by left ventricle radiofrequency ablation. Sham-operated rats (sham) were used as controls. At 6 wk after surgery, HF rats exhibited cardiac dysfunction with a dramatic increase in left ventricular end-diastolic pressure. By means of stationary in vivo microperfusion and pH-dependent sodium uptake, we demonstrated that NHE3 transport activity was significantly higher in the proximal tubule of HF compared with sham rats. Increased NHE3 activity was paralleled by increased renal cortical NHE3 expression at both protein and mRNA levels. In addition, the baseline PKA-dependent NHE3 phosphorylation at serine 552 was reduced in renal cortical membranes of rats with HF. Collectively, these results suggest that NHE3 is upregulated in the proximal tubule of HF rats by transcriptional, translational, and posttranslational mechanisms. Enhanced NHE3-mediated sodium reabsorption in the proximal tubule may contribute to extracellular volume expansion and edema, the hallmark feature of HF. Moreover, our study emphasizes the importance of undertaking a cardiorenal approach to contain progression of cardiac disease.