Preparation and characterization of nanosized SrBi2Nb2O9 powder by the combustion synthesis

This work presents the preparation of SrBi2Nb2O9 (SBN) directly by the combustion synthesis. Strontium nitrate, niobium ammonium oxalate (NH4H2[NbO-(C2O4)(3)].3H(2)O) and bismuth oxide were used as oxidant reactants and urea as fuel. The influence of the fuel was evaluated by the addition of different fuel amounts (50%, 100%, 200% and 300%), 100% being the stoichiometric proportion. The XRD patterns showed that the SBN perovskite crystallized as the majority phase. The as-synthesized stoichiometric powder presented a specific surface area of around 13 m(2)/g and a mean grain size of around 16 nm. Dilatometric measurements showed that the maximum sintering rate occurs at 1275degreesC. The determination of the ferroparaelectric transition showed a Curie temperature (T-c) of 429degreesC. (C) 2002 Elsevier B.V. B.V. All rights reserved.

Wet deposition of major ions in a rural area impacted by biomass burning emissions

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Organic and conventional fertilisation procedures on the nitrate, antioxidants and pesticide content in parts of vegetables

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Atmospheric emission of reactive nitrogen during biofuel ethanol production

This paper evaluates emissions to the atmosphere of biologically available nitrogen compounds in a region characterized by intensive sugar cane biofuel ethanol production. Large emissions of NH(3) and NO,, as well as particulate nitrate and ammonium, occur at the harvest when the crop is burned, with the amount of nitrogen released equivalent to similar to 35% of annual fertilizer-N application. Nitrogen oxides concentrations show a positive association with fire frequency, indicating that biomass burning is a major emission source, with mean concentrations of NO, doubling in the dry season relative to the wet season. During the dry season biomass burning is a source of NH3, with other sources (wastes, soil, biogenic) predominant during the wet season. Estimated NO(2)-N, NH(3)-N, NO(3)(-)-N and NH(4)(+)-N emission fluxes from sugar cane burning in a planted area,of ca. 2.2 x 10(6) ha are 11.0, 1.1, 0.2, and 1.2 Gg N yr(-1), respectively.

Degradation of the antibiotic amoxicillin by photo-Fenton process - Chemical and toxicological assessment

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Soluble phosphate accumulation by Aspergillus niger from fluorapatite

In order to determine conditions that may provide greater solubilization of insouluble phosphate, the fungus Aspergillus niger was grown in a stationary culture containing modified citrate medium supplemented with 800 mg fluorapatite per litre. Solubilization of insouluble phosphate increased with fungal growth, reaching a maximum after 11 days of culture. Soluble phosphate levels were correlated with pH of the culture medium but not with titratable acidity values, probably due to the metabolic activity of the fungus resulting from consumption of sugar in the culture medium. Fructose, glucose, xylose, and sucrose were the carbohydrates that favoured fluorapatite solubilization the most when compared with galactose and maltose. Although increasing fructose concentrations in the culture medium favoured mycelial growth, increased total acidity and a fall in pH, soluble phosphate levels were reduced, probably owing to consumption by the rapidly growing fungus. Among the nitrogen sources tested, ammonium salts favoured the production of larger amounts of soluble phosphate than organic nitrogen (peptone or urea) or nitrate, corresponding to the lowest pH and highest titratable acidity values obtained. © 1988 Springer-Verlag.

Preparation and characterization of spherical yttrium iron garnet via coprecipitation

The purpose of this work is to obtain spherical particles yttrium iron garnet (YIG) by coprecipitation technique. The spherical particles were obtained from either nitrate or chloride salt solutions by controlling the precipitation medium. Different agents of dispersion such as PVP and ammonium iron sulfate were used to optimize the shape and size of YIG. Samples were characterized by X-ray diffraction, scanning electron microscopy and vibrating sample magnetometry. The results show that the samples phase transition takes place at 850°C (orthorhombic phase) and at 1200°C (cubic phase). Spherical shape particles, with diameter of around 0.5 μm, present magnetization values close to the bulk value (26 emu g -1). © 2001 Elsevier Science B.V. All rights reserved.

Effects of nitrate concentration on larval development of the giant river prawn, Macrobrachium rosenbergii

The effect of nitrate concentration on giant river prawn, Macrobrachium rosenbergii, larvae was investigated. Survival rate, weight gain, and larval development were evaluated for different concentrations of nitrate in three experiments. The experiments were divided i n to two phases. In the first phase, larvae from stages I through VIII were analysed, while in the second phase larvae from stage VIII through post-larvae metamorphosis were analysed. Oxygen consumption was also determined for zoea I, II, and VIII exposed to 0, 700, and 1,000 mg/L of nitrate-N. No effect was observed for concentrations up to 180 mg/L NO3-N (experiments I and II), and nitrate levels as 1,000 mg/L NO3-N did not affect survival in the first phase of the third experiment. On the other hand, larval stage index (LSI) and weight gain decreased as nitrate-N concentration increased from 0 to 1,000 mg/L. In the second phase, survival and metamorphosis rate decreased as nitrate concentration increased, according to a linear model. The effect of nitrate levels on weight gain followed a curvilinear pattern. Larval respiration decreased in the water where nitrate was added, but only during stage II. The results demonstrated that nitrate presents extremely low toxicity for giant river prawn larvae, and data were related to the levels of nitrate that usually occur in larviculture systems also discussed. Therefore, nitrate is not a limiting factor for giant river prawn larviculture. © 2003 by The Haworth Press, Inc. All rights reserved.

Water table effects on bean yield and nitrate distribution in the soil profile

In order to evaluate the bean yield under different water table levels as well as the moisture and nitrate distribution in the soil profile, a field experiment was carried out at the experimental area from the College of Agronomic Sciences - UNESP, Botucatu, SP, Brazil. Beans were grown in field lysimeters and subjected to five water table depths:30; 40; 50; 60 and 70 cm. The moisture in the soil profile was gravimetrically determined through samples obtained at 10; 20; 30; 40; 50; 60 and 70cm of depth. The water table depths of 30cm and 40cm showed the highest productivities (3,228.4 kg.ha-1 and 3,422.1 kg.ha-1, respectively), showing no statistical differences between each other. The highest productivity was related to the two most elevated water table levels (30 and 40cm), which provided the highest moisture average values on basis of volume in the soil profile (33.3 e 31%) as well as the consumptive use of water (416 and 396 mm). The nitrate content during the bean cycle at the extraction depth of 60cm has been under the safe drinking limit of 10 mg.1-1 for water table depths of 30; 40; 50 and 60cm, showing the denitrification effectiveness as a way of controlling water table from nitrate pollution. The water table handling allowed the attainment of high bean productivity levels, as well as the reduction of the nitrate level.

Efeito da calagem e sulfato de amônio no algodão. I - Transporte de cátions e ânions no solo

Applying lime on the soil surface in soils managed under no-tillage has caused an excess of basic cations in the most superficial layers of the soil profile. On the other hand, subsoil acidity is considered a constraint to the development of deep plant roots. The objective of this study was to evaluate Ca 2+, Mg 2+, NO 3- and SO 4 2- leaching in the soil profile as affected by liming and top dressing nitrogen fertilization in cotton, grown with straw cover on the soil surface. Cotton plants (Gossypium hirsutum) were grown for 60 days in PVC columns filled with a Distroferric Red Latosol (sand loam Rhodic Oxisol) with liming applied over the straw on the soil surface, incorporated liming 0-20 cm deep, or without liming. Nitrogen was applied at rates of 0, 50, 100 and 150 kg ha -1 as ammonium sulfate. The PVC columns were set up in layers of 0-5, 5-10, 10-20, 20-30 and 30-30 cm, totaling 15.71 dm 3. The ammonium sulfate application caused intense leaching of SO 4 2- in the soil, irrespective of the lime application method. Liming increased the concentration of NO 3 in the 0-20 cm soil layer, whereas the correction of the soil acidity did not affect the NO 3- concentration in the 30-50 cm soil layer. The influence of ammonium sulfate on Ca 2+ leaching below 20 cm was only observed in the soil with incorporated lime. Nitrogen application resulted in extensive Mg 2+ leaching from the soil, regardless of the lime application method. In the soil layer below 30 cm, SO 4 2- presented a higher correlation than NO 3- in the formation of ionic pairs with Ca 2+ and Mg 2+.

Pattern of silver nitrate-staining during meiosis and spermiogenesis in testicular lobes of Antiteuchus tripterus (Heteroptera: Pentatomidae)

The pattern of silver nitrate (Ag)-staining differed among testicular lobes of Antiteuchus tripterus. In general, these differences are in regard to the number, size, shape, coloring intensity, and location of the stained bodies or masses, observed during meiosis and spermiogenesis. These characteristics were similar in lobes 1-3. Lobes 4-6, however, differed from each other and from lobes 1-3 as well. Because the Ag-staining method is specific for nucleolar organizing regions and nucleolar material, the observations in meiosis of lobes 1-3 suggested the presence of a single pair of nucleolar organizing region-bearing chromosomes in A. tripterus, as previously found in other Pentatomidae species. In general, the amount of Ag-stained material seen in meiosis of the testicular lobes 1-3 of A. tripterus is smaller than in the other lobes. The differences among lobes observed during spermiogenesis included a striking variation in morphology of the Ag-stained material found in the head and tail of the spermatids. Given that the key role of the nucleolar material is to participate in protein synthesis, interlobular variations seem to be related to the different functions attributed to each lobe (reproduction to lobes 1-3 and basically nutrition to lobes 4-6). To our knowledge, this is the first time that the nucleolar material was studied in each testicular lobe during spermatogenesis. The present observations encourage further studies since, in addition to being of basic biological interest, several Pentatomidae species are agricultural pests and added knowledge of their biology, mainly in reproduction, may be important for the development of control strategies. ©FUNPEC-RP.

Water table effects on bean yield and nitrate distribution in the soil profile

In order to evaluate the bean yield under different water table levels as well as the moisture and nitrate distribution in the soil profile, a field experiment was carried out in the experimental area of the College of Agricultural Sciences - UNESP, Botucatu, SP, Brazil. Beans were grown in field lysimeters under five water table depths: 30; 40; 50; 60 and 70 cm. The moisture in the soil profile was determined gravimetrically using samples collected at 10; 20; 30; 40; 50; 60 and 70 cm deep. The water table depths of 30cm and 40cm showed the highest productivities (3,228.4kg.ha-1 and 3,422.1kg.ha-1, respectively), with no statistical differences between them. The highest productivity was related to the two highest water table levels (30 and 40cm), which provided the highest moisture average values on the basis of volume in the soil profile (33.3 e 31%) as well as the consumptive use of water (416 and 396mm). The nitrate content during the bean cycle at the extraction depth of 60cm was below the safe drinking limit of 10mg.1-1 for water table depths of 30; 40; 50 and 60cm, which shows the denitrification efficiency as a way of controlling nitrate pollution in water tables. The management of water table can lead to high levels of bean yield and to a better control of nitrate pollution in underground water.

Effect of 6-months of physical exercise on the nitrate/nitrite levels in hypertensive postmenopausal women

Background: Evidences have showed that the incidence of arterial hypertension is greater in postmenopausal women as compared to premenopausal. Physical inactivity has been implicated as a major contributor to weight gain and abdominal obesity in postmenopausal women and the incidence of cardiovascular disease increases dramatically after menopause. Additionally, more women than men die each year of coronary heart disease and are twice as likely as men to die within the first year after a heart attack. A healthy lifestyle has been strongly associated with the regular physical activity and evidences have shown that physically active subjects have more longevity with reduction of morbidity and mortality. Nitric oxide (NO) produced by endothelial cells has been implicated in this beneficial effect with improvement of vascular relaxing and reduction in blood pressure in both laboratory animals and human. Although the effect of exercise training in the human cardiovascular system has been largely studied, the majority of these studies were predominantly conducted in men or young volunteers. Therefore, the aim of this work was to investigate the effects of 6 months of dynamic exercise training (ET) on blood pressure and plasma nitrate/nitrite concentration (NOx-) in hypertensive postmenopausal women. Methods: Eleven volunteers were submitted to the ET consisting in 3 days a week, each session of 60 minutes during 6 months at moderate intensity (50% of heart rate reserve). Anthropometric parameters, blood pressure, NOx- concentration were measured at initial time and after ET. Results: A significant reduction in both systolic and diastolic blood pressure values was seen after ET which was accompanied by markedly increase of NOx- levels (basal: 10 ± 0.9; ET: 16 ± 2 μM). Total cholesterol was significantly reduced (basal: 220 ± 38 and ET: 178 ± 22 mg/dl), whereas triglycerides levels were not modified after ET (basal: 141 ± 89 and ET: 147 ± 8 mg/dl). Conclusion: Our study shows that changing in lifestyle promotes reducftion of arterial pressure which was accompanied by increase in nitrite/nitrate concentration. Therefore, 6-months of exercise training are an important approach in management arterial hypertension and play a protective effect in postmenopausal women. © 2009 Zaros et al; licensee BioMed Central Ltd.

Nitrate Removal on a Cu/Cu2O Photocathode under UV Irradiation and Bias Potential

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Estímulo da solubilização de fosfato resultante da co-inoculação de Aspergillus niger e Burkholderia cepacia

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)