166 research outputs found

    “On the fly” characterization of YbIII:ErIII co-doped upconversion nanoparticle nonlinear optical response from single-particle trajectories

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    Spectroscopic characterization of individual nanoparticles is essential for understanding their structure-property relationship and for applications. Upconversion nanoparticles (UCNPs) in condensed phases can undergo both nonlinear optical and stochastic dynamics when interacting with near-infrared sources. By integrating optical trapping microspectroscopy, stochastic dynamics and light-matter interactions experiments and simulations, in the present work we study how individual trajectories of YbIII:ErIII co-doped UCNPs can be used to perform “on the fly” characterization of their nonlinear optical power-law response upon near-infrared excitation. We illustrate the methodology in the case of freely diffusing and optically trapped UCNPs as well as with particles bound to the substrate. The approach presented in this work can be applied to UCNPs with varying composition and morphological features, particularly in single-particle studies.Fil: Cavalcante, Isabela N.. Universidade Estadual de Campinas; BrasilFil: Marchi, María Claudia. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Física de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Física de Buenos Aires; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química, Física de los Materiales, Medioambiente y Energía. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química, Física de los Materiales, Medioambiente y Energía; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Centro de Microscopías Avanzadas; ArgentinaFil: Sigoli, Fernando A.. Universidade Estadual de Campinas; BrasilFil: de Sousa Filho, Paulo C.. Universidade Estadual de Campinas; BrasilFil: Barja, Beatriz Carmen. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química, Física de los Materiales, Medioambiente y Energía. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química, Física de los Materiales, Medioambiente y Energía; ArgentinaFil: Nome, René A.. Universidade Estadual de Campinas; Brasi

    Deficiências minerais de bovinos na sub-região dos Paiaguás, no Pantanal Mato-grossense. I. Cálcio, fósforo e magnésio

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    This experiment was carried out in order to survey soil defficiency on calcium (Ca), phosphorus (P) and magnesium (Mg), either in forage or in animal tissues, during four different periods of the year, in the region of Paiaguás, lowlands of Mato Grosso State, Brazil. Calcium present in the soil, indifferent on geomorphic units and forage species, ranged through the year from 0.057 to 0.170 meq/100 g of soil, 0.13% to 0.24% in forages, 33.67% to 36.88% in bone P, ranged from 1.6 ppm to 5.16 ppm, in the soil 0.07% to 0.15% forages, 2.59 to 4.38 mg/100 ml in blood serum; 14.12% to 16.64% in bone. Mg ranged from 0.032 to 0.055 meq/100 g in soil, 0.07% to 0.12% in forages, 1.35 to 2.86 mg/100 ml in blood serum and 0.42% to 0.55% in bone. Mineral concentration observed in the soils, forages, bone and blood tissues determined shortages of phosphorus in the animals during four periods, calcium during one period and magnesium during three periods.Realizou-se um levantamento das deficiências de cálcio (Ca), fósforo (P) e magnésio (Mg) no solo, nas forrageiras e tecidos animais, em quatro épocas do ano, na sub-região dos Paiaguás, no Pantanal Mato-grossense. O Ca no solo, independentemente de unidade geomórfica e espécies forrageiras, variou durante o ano de 0,057 a 0,170 meq/100 g de solo, nas forrageiras de 0,13% a 0,24%, no osso 33,67% a 36,88%, P no solo de 1,6 ppm a 5,16 ppm, nas forrageiras de 0,07% a 0,15%, no soro sanguíneo de 2,59 a 4,38 mg/100 ml de soro, no osso de 14,12% a 16,64%; Mg no solo de 0,032 a 0,055 meq/100 g de solo nas forrageiras de 0,07% a 0,12%, no soro sanguíneo de 1,35 a 2,86 mg/100 ml de soro e no osso de 0,42% a 0,55%. As concentrações de minerais verificadas nos solos, forrageiras e nos tecidos animais determinaram com que os animais apresentassem deficiência de P nas quatro épocas estudadas, Ca em uma época e Mg em três épocas

    Seasonality Role on the Phenolics from Cultivated Baccharis dracunculifolia

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    Baccharis dracunculifolia is the source of Brazilian green propolis (BGP). Considering the broad spectrum of biological activities attributed to green proplis, B. dracunculifolia has a great potential for the development of new cosmetic and pharmaceutical products. In this work, the cultivation of 10 different populations of native B. dracunculifolia had been undertaken aiming to determine the role of seasonality on its phenolic compounds. For this purpose, fruits of this plant were collected from populations of 10 different regions, and 100 individuals of each population were cultivated in an experimental area of 1800 m2. With respect to cultivation, the yields of dry plant, essential oil and crude extract were measured monthly resulting in mean values of 399 ± 80 g, 0.6 ± 0.1% and 20 ± 4%, respectively. The HPLC analysis allowed detecting seven phenolic compounds: caffeic acid, ferulic acid, aromadendrin-4′-methyl ether (AME), isosakuranetin, artepillin C, baccharin and 2-dimethyl-6-carboxyethenyl-2H-1-benzopyran acid, which were the major ones throughout the 1-year monthly analysis. Caffeic acid was detected in all cultivated populations with mean of 4.0%. AME displayed the wide variation in relation to other compounds showing means values of 0.65 ± 0.13% at last quarter. Isosakuranetin and artepillin C showed increasing concentrations with values between 0% and 1.4% and 0% and 1.09%, respectively. The obtained results allow suggesting that the best time for harvesting this plant, in order to obtain good qualitative and quantitative results for these phenolic compounds, is between December and April

    On the correlation between electronic intramolecular delocalization and Au-S bonding strength of ruthenium tetraammine SAMs

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    Trans-[Ru(L)(NH3)4(L’)](PF6)n type complexes, where L = 4-cyanopyridine (CNpy), NCS-, CN-, and L’ = CNpy, 1,4-dithiane (1,4-dt), 4-mercaptopyridine (pyS) and thionicotinamide (tna), were synthesized and characterized. SAMs on gold of the complexes containing sulfur were studied by reductive desorption and SERS spectroscopy. Depending on the nature of L’, the withdrawing capability of the CNpy ligand is strong enough to partially oxidize the ruthenium atom and, as a consequence, delocalize the s electronic density from the trans located ligand. The reductive desorption results showed that the stability of the SAMs is directly related to this effect

    Prevention of hypertension in patients with pre-hypertension: protocol for the PREVER-prevention trial

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    <p>Abstract</p> <p>Background</p> <p>Blood pressure (BP) within pre-hypertensive levels confers higher cardiovascular risk and is an intermediate stage for full hypertension, which develops in an annual rate of 7 out of 100 individuals with 40 to 50 years of age. Non-drug interventions to prevent hypertension have had low effectiveness. In individuals with previous cardiovascular disease or diabetes, the use of BP-lowering agents reduces the incidence of major cardiovascular events. In the absence of higher baseline risk, the use of BP agents reduces the incidence of hypertension. The PREVER-prevention trial aims to investigate the efficacy, safety and feasibility of a population-based intervention to prevent the incidence of hypertension and the development of target-organ damage.</p> <p>Methods</p> <p>This is a randomized, double-blind, placebo-controlled clinical trial, with participants aged 30 to 70 years, with pre-hypertension. The trial arms will be chlorthalidone 12.5 mg plus amiloride 2.5 mg or identical placebo. The primary outcomes will be the incidence of hypertension, adverse events and development or worsening of microalbuminuria and of left ventricular hypertrophy in the EKG. The secondary outcomes will be fatal or non-fatal cardiovascular events: myocardial infarction, stroke, heart failure, evidence of new sub-clinical atherosclerosis, and sudden death. The study will last 18 months. The sample size was calculated on the basis of an incidence of hypertension of 14% in the control group, a size effect of 40%, power of 85% and P alpha of 5%, resulting in 625 participants per group. The project was approved by the Ethics committee of each participating institution.</p> <p>Discussion</p> <p>The early use of blood pressure-lowering drugs, particularly diuretics, which act on the main mechanism of blood pressure rising with age, may prevent cardiovascular events and the incidence of hypertension in individuals with hypertension. If this intervention shows to be effective and safe in a population-based perspective, it could be the basis for an innovative public health program to prevent hypertension in Brazil.</p> <p>Trial Registration</p> <p>Clinical Trials <a href="http://www.clinicaltrials.gov/ct2/show/NCT00970931">NCT00970931</a>.</p

    Expression profile of genes associated with mastitis in dairy cattle

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    In order to characterize the expression of genes associated with immune response mechanisms to mastitis, we quantified the relative expression of the IL-2, IL-4, IL-6, IL-8, IL-10, IFN-γ and TNF- α genes in milk cells of healthy cows and cows with clinical mastitis. Total RNA was extracted from milk cells of six Black and White Holstein (BW) cows and six Gyr cows, including three animals with and three without mastitis per breed. Gene expression was analyzed by real-time PCR. IL-10 gene expression was higher in the group of BW and Gyr cows with mastitis compared to animals free of infection from both breeds (p < 0.05). It was also higher in BW Holstein animals with clinical mastitis (p < 0.001), but it was not significant when Gyr cows with and without mastitis were compared (0.05 < p < 0.10). Among healthy cows, BW Holstein animals tended to present a higher expression of all genes studied, with a significant difference for the IL-2 and IFN- γ genes (p < 0.001). For animals with mastitis no significant difference in gene expression was observed between the two breeds. These findings suggest that animals with mastitis develop a preferentially cell-mediated immune response. Further studies including larger samples are necessary to better characterize the gene expression profile in cows with mastitis

    Erratum to: The study of cardiovascular risk in adolescents – ERICA: rationale, design and sample characteristics of a national survey examining cardiovascular risk factor profile in Brazilian adolescents

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    Sugarcane (Saccharum X officinarum): A Reference Study for the Regulation of Genetically Modified Cultivars in Brazil

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    Global interest in sugarcane has increased significantly in recent years due to its economic impact on sustainable energy production. Sugarcane breeding and better agronomic practices have contributed to a huge increase in sugarcane yield in the last 30 years. Additional increases in sugarcane yield are expected to result from the use of biotechnology tools in the near future. Genetically modified (GM) sugarcane that incorporates genes to increase resistance to biotic and abiotic stresses could play a major role in achieving this goal. However, to bring GM sugarcane to the market, it is necessary to follow a regulatory process that will evaluate the environmental and health impacts of this crop. The regulatory review process is usually accomplished through a comparison of the biology and composition of the GM cultivar and a non-GM counterpart. This review intends to provide information on non-GM sugarcane biology, genetics, breeding, agronomic management, processing, products and byproducts, as well as the current technologies used to develop GM sugarcane, with the aim of assisting regulators in the decision-making process regarding the commercial release of GM sugarcane cultivars
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