Desenvolvimento de um dispositivo para obtenção de monocristais de ligas à base de cobre

This paper describes the drawing, construction and optimization of a device, which can be used to obtain single crystals of different metallic materials with melting point from 550 to 1050°C. Components of ease obtaining and of low cost were used. The device was based on the modified Bridgman technique and it was used to obtain single crystals of copper-based alloys. The temperature axial profiles and a difference less then 1% in the temperature between the wall and the center of the ceramic tube in the critical region for obtaining single crystals of good quality indicated that the oven presents a good thermal stability. Single crystals of CuZnAl and CuAlAg alloys of good quality were growth and characterized using optical microscopy and Laüe X-ray back reflection.

Uso do óxido nítrico em pediatria

Objective: To review the literature on inhaled nitric oxide and to describe its main clinical applications in pediatrics. Sources of data: A 10 year literature review with selection of the most important publications on inhaled nitric oxide, using the Medline and Cochrane Systematic Review databases. Summary of the findings: This review was organized as follows: introduction; metabolism and biological effects; clinical applications; dosage, gas administration and weaning; precautions and side-effects. Inhaled nitric oxide use was described in persistent pulmonary hypertension and hypoxia of the newborn, acute respiratory distress syndrome, primary pulmonary hypertension, heart surgery, chronic obstructive pulmonary disease, sickle cell anemia, and bronchospastic disease. Conclusions: Inhaled nitric oxide is a therapeutic approach with wide clinical applications in pediatrics. Its use is safe when administered in pediatric intensive care units under strict monitoring. As a pulmonary vasodilator, nitric oxide has beneficial effects on gas exchange and ventilation. Controlled trials, focusing on early gas administration should be performed under many clinical conditions, especially acute respiratory distress syndrome.

O óxido nítrico (NO) no controle neural da pressão arterial: Modulação da transmissão glutamatérgica no NTS

The neuromodulatory effect of nitric oxide (NO) on glutamatergic transmission within the NTS related to cardiovascular regulation has been widely investigated. Activation of glutamatergic receptors in the NTS stimulates the production and release of NO and other nitrosyl substances with neurotransmitter/neuromodulator properties. The presence of NOS, including the protein nNOS and its mRNA in vagal afferent terminals in the NTS and nodose ganglion cells suggest that NO can act on glutamatergic transmission. We previously reported that iontophoresis of L-NAME on NTS neurons receiving vagal afferent inputs significantly decreased the number of action potentials evoked by iontophoretic application of AMPA. In addition, iontophoresis of the NO donor papaNONOate enhanced spontaneous discharge and the number of action potentials elicited by AMPA, suggesting that NO could be facilitating AMPA-mediated neuronal transmission within the NTS. Furthermore, the changes in renal sympathetic discharge during activation of baroreceptors and cardiopulmonary receptors involve activation of AMPA and NMDA receptors in the NTS and these responses are attenuated by microinjection of L-NAME in the NTS of conscious and anesthetized rats. Cardiovascular responses elicited by application of NO in the NTS are closely similar to those obtained after activation of vagal afferent inputs, and L-glutamate is the main neurotransmitter of vagal afferent fibers. In this review we discuss the possible neuromodulatory mechanisms of central produced/released NO on glutamatergic transmission within the NTS.

Toxicidade aguda do sulfato de cobre e do extrato aquoso de folhas secas de nim para o caramujo (Pomacea canaliculata)

Snails can become an environmental and economic problem, causing substantial losses. The objective of this work was to estimate the acute toxicity of copper sulfate pentahydrate (CuSO4.5H2O) and the aqueous extract of dried neem leaves on snails (P. canaliculata) under laboratory conditions. In order to estimate the lethal concentration 50% (LC (I)50;96h), snails were exposed to six increasing copper sulfate concentrations (0.0; 0.01; 0.03; 0.05; 0.07 and 0.1 mg L-1) and six increasing concentrations of aqueous extract of dried neem leaves 0.0; 100; 125; 150; 175 and 200 mL aqueous extract of dried neem leaves L-1 water, equivalent to (0.0; 1.18; 1.47; 1.77; 2.06 and 2.36 mg azadirachtin L -1), in triplicate and one control treatment in an entirely random delineation. Estimated LC (I)50;96h, of copper sulfate was 0.02 mg copper sulfate L-1, with a 0.01 mg L-1 lower limit and a 0.03 mg L-1 upper limit. Estimated lethal concentration 50% of the aqueous extract of dried neem leaves was 142.75 mL L-1, equivalent to 1.68 mg L-1 of azadirachtine, with a 130.89 mL L-1 (1.54 mg L-1) low limit and 155.69 mL L-1 (1.83 mg L -1) as the upper limit.

El complejo de cobre de la Southern Perú

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Aplicação da metodologia de superfície de resposta na remediação de um solo arenoso contaminado artificialmente com cobre

Soil flushing is an alternative remediation technology for soils contaminated with heavy metals, which the main contaminant removing process consists in percolating an extraction solution. This work aimed to use the response surface methodology to point out combinations among the parameters of the extraction solution (Na2EDTA concentration, volume e pH) in order to reduce the concentration of copper in a sandy soil to risk levels lower than the intervention levels for exposure scenarios adopted by the Environmental Company of Sao Paulo State. Thus, a series of tests in leaching columns were carried out using a Fluvisol artificially contaminated (1257,3 mg kg-1). The tests were conducted in triplicate and setup a central composite rotatable design with 15 different parameters combinations of the extraction solution and one replicate in the center point. Using 5% significance level, the adjusted model (R2 = 0,98) indicated combinations of Na2EDTA concentration, pH and volume of the extraction solution which allow reduction of copper concentration below levels reported by environmental agency of Sao Paulo State for industrial, residential, agricultural or maximum exposure scenarios.

Una estrategia de desarrollo basada en recursos naturales: análisis 'cluster' del complejo de cobre de la Southern Perú

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Mapeamento de Paleosuperfícies associadas a identificação de depósitos supérgenos de cobre como ferramenta de exploração mineral na região de Itapeva e Ribeirão Branco- Vale do Ribeira, estado de São Paulo, Brasil

A few examples of supergene ore formation and their interaction with morphogenesis (palaeosurfaces) and weathering mineralogy are discussed. Geomorphological and mineralogical records to characterize palaeosurfaces associate the weathering of primary minerals and their relationship with concentrations of cooper and iron ore deposits in southeastern state of São Paulo, Brazil. We have distinguished two palaeosurfaces generated by several weathering phases and controlled by the geological framework. The first and oldest upper palaeosurfaces (900 - 1000 m a.s.l.), situated in Riberão Branco (Alto do Brancal), were developed on silico-limestones. It is formed by typical iron laterites enriched by secondary products of cooper. The second and younger level palaeosurfaces located in Itapeva (Santa Blandina and Bairro do Sambra). This palaeosurface is formed by copper percolating through the weathered rock (saprolite). Other features can be observed like neo-formed products in laterites. They are classified into two types: clay like silico- cupriferous products (with noticeable amounts of iron) and copper minerals (crysocolla, in their flat slopes). These features allowed the presence of copper ores and their morphogenesis control will help in the exploration and prospecting of supergene ore mineral.

Síndrome holandés, regalías mineras y políticas de gobierno para un país dependiente de recursos naturales: el cobre en Chile

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El impacto del programa de estabilización y las reformas estructurales sobre el desempeño ambiental de la minería de cobre en el Perú: 1990-1997

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El desarrollo de la minería del cobre en la segunda mitad del siglo XX

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Situación y tendencias recientes del mercado del cobre

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Determinantes del precio spot del cobre en las bolsas de metales

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Alimentação de leitões com dietas contendo soro de leite fermentado mais zinco e cobre orgânico

An experiment was carried out to evaluate the performance of piglets fed rations containing fermented milk and zinc and copper amino acid complex. Sixty four piglets, littermates, were used. The experimental design was based on random block with two dietary treatments. One of these contained a basal diet (DB) with ZnO e CuSO 4 and the other one with the DB, but without CuSO 4 and with the addition of fermented milk and zinc and copper amino acid complex (SLF Lact +ZnCuAA). There were eight replicate pens per treatment, and pigs were grouped at 4 per pen. The SLF Lact + ZnCuAA didn't not affect (p>0.05) final live weight of the piglets. However, live weight was different (p<0.01) between males and females (24.3 vs. 24.0 kg) at end of experiment. The feed intake of animals feed with SLF Lact+ZnCuAA was higher (p<0.01) in 8% in the first 14 days (0.261 vs. 0.239 kg/d), 15% from 15 to 28 days (0.756 vs. 0.675 kg/ d) and 12% from 29 to 42 days (1.091 vs. 0.962 kg/ d) compared to control group. Daily average feed intake in the experimental period was 11% higher (p<0.01) for the animals fed with the diet contained SLF Lact+ZnCuAA. Weight gain of the treatment with SLFL act+ZnCuAA was higher (p<0.01) by 14% from 0 to 14 days (0.176 vs. 0.152 kg/d), 11% from 15 to 28 days (0.564 vs. 0.500 kg/d) and 12% from 29 to 42 days (0,572 vs. 0,501 kg/d). Average daily weight gain of 42 days of trial of treatment with SLF Lact +ZnCuAA was 12% higher (p<0.01) compared to control group (0.437 vs. 0.384 kg/d). Feed conversion ratio was 8% lower (p<0.01) for treatment with SLF Lact+ZnCuAA in the first 14 days (1.487 vs. 1.614). Supplementation with fermented milk and zinc and copper amino acid complex in diets containing zinc oxide improved growth performance of weanling piglets.

Análisis empírico del comportamiento de las exportaciones no cobre en Chile: 1963-1990

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