924 resultados para Copper mines and mining


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Includes bibliographical references.

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The benefit of windbreaks and copper sprays for control of citrus canker caused by Xanthomonas axonopodis pv. citri was investigated in a commercial citrus orchard located in a citrus canker endemic area in southern Brazil. Control of canker was evaluated as incidence and severity of lesions on foliage and by the effect on premature leaf and fruit drop for three production seasons. Effect of the treatments on fruit production was evaluated as incidence of citrus canker on prematurely abscised fruits and harvested fruits. Copper application significantly reduced damage to foliage and fruit, while windbreaks made little contribution to disease control. Copper sprays increased fruit yield for 3 years. This could be attributed to lower incidence of fruit with lesions and fewer fruits abscised due to canker infection. Incidence and severity on the leaves were inversely related to the number of fruits harvested per tree and directly related to the number of fruits abscised per tree. Published by Elsevier Ltd.

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BACKGROUND: There has been growing interest in sodium copper chlorophyllin (Cu-Chl) as a food colourant and supplement owing to its beneficial biological activities. Studies have revealed that this green pigment inhibits experimental carcinogenesis and interacts with proteins and genotoxic agents. Health-related activities have also been associated with the prevention of lipid peroxidation. However, intestinal absorption of this pigment has been considered insignificant, raising questions of whether eventual biological properties are related to pre- or post-absorptive actions. In this study, intestinal absorption of Cu-Chl and its appearance in serum and organs were estimated by high-performance liquid chromatography analysis in rat feeding experiments. The effect of ingested Cu-Chl on lipid peroxidation was analysed by measuring thiobarbituric acid-reactive substances and antioxidant enzyme activities in hepatic and brain tissues of oxidative stress-induced rats. RESULTS: The two main components of commercial Cu-Chl, namely Cu-chlorin e(6) and Cu-chlorin e(4), showed different digestive behaviours, and only Cu-chlorin e4 was found in serum, liver and kidneys. Antioxidant activity in vivo could be observed in brain and seemed to be related to in situ protection but not to antioxidant enzyme modulation. CONCLUSION: As at least one of the major components of Cu-Chl is effectively absorbed, further pharmacolkinetic studies are encouraged to access absorption rates and the role of ingested copper chlorophyllins in mammals. (C) 2009 Society of Chemical Industry

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The main goal of this research study was the removal of Cu(II), Ni(II) and Zn(II) from aqueous solutions using peanut hulls. This work was mainly focused on the following aspects: chemical characterization of the biosorbent, kinetic studies, study of the pH influence in mono-component systems, equilibrium isotherms and column studies, both in mono and tri-component systems, and with a real industrial effluent from the electroplating industry. The chemical characterization of peanut hulls showed a high cellulose (44.8%) and lignin (36.1%) content, which favours biosorption of metal cations. The kinetic studies performed indicate that most of the sorption occurs in the first 30 min for all systems. In general, a pseudo-second order kinetics was followed, both in mono and tri-component systems. The equilibrium isotherms were better described by Freundlich model in all systems. Peanut hulls showed higher affinity for copper than for nickel and zinc when they are both present. The pH value between 5 and 6 was the most favourable for all systems. The sorbent capacity in column was 0.028 and 0.025 mmol g-1 for copper, respectively in mono and tri-component systems. A decrease of capacity for copper (50%) was observed when dealing with the real effluent. The Yoon-Nelson, Thomas and Yan’s models were fitted to the experimental data, being the latter the best fit.

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Biochemistry, 2004, 43 (46), pp 14566–14576 DOI: 10.1021/bi0485833

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To investigate the trace elements (TE) losses and status after trauma, 11 severely injured patients (Injury Severity Score: 29 +/- 6), admitted to the ICU were studied from the day of injury (D0) until D25. Balance studies were started within 24 hours after injury, until D7. Serum and urine samples were collected from D1 to D7, then on D10, 15, 20, and 25. Intravenous TE supplementation was initiated upon admission. SERUM: Selenium (Se) and zinc (Zn) levels were decreased until D7 and were normal thereafter. LOSSES: TE urinary excretions were higher than reference ranges until D20 in all patients. Fluid losses through drains contained large amounts of TE. BALANCES: Balances were slightly positive for copper (Cu) and Zn, and negative for Se from D5 to D7 despite supplements. Cu status exhibited minor changes compared to those observed with the Zn and Se status: Serum levels were decreased and losses increased. Considering the importance of Se and Zn in free radical scavenging, anabolism, and immunity, current recommendations for TE supplements in severely traumatized patients ought to be revised.

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Copper-67 has comparable beta-particle emissions to that of 131I, but it displays more favorable gamma emission characteristics for application in radioimmunotherapy (RIT). This study investigates the potential of 67Cu-labeled monoclonal antibody (MAb) 35 for RIT of colorectal carcinoma. METHODS: Biokinetics of simultaneously injected 67Cu- and 125I-labeled MAb35 were studied in six patients scheduled for surgery of primary colorectal cancer. RESULTS: Whole-body clearance (T 1/2) of 67Cu, estimated from sequential anterior and posterior whole-body scans and corrected for decay of 67Cu, was 41 hr. Serum clearance of 67Cu was faster (27.41 hr) than that of 125I (38.33 hr). Mean tumor uptake of the 67Cu-labeled compound (0.0133% ID/g) exceeded that of 125I (0.0095% ID/g), and tumor-to-blood ratios were higher for 67Cu than for 125I, with averages of 6.07 and 2.41, respectively. The average 67Cu/125I ratio was 1.9 for tumor uptake, 0.7 for blood and 2.6 for tumor-to-blood ratios. Nonspecific liver uptake of 67Cu as calculated from whole-body scans was high in four patients, up to 25% of residual whole-body activity at 48 hr, but did not increase with time. We also observed some nonspecific bowel activity, as well as moderate to high uptake in benign polyps. CONCLUSION: Copper-67-labeled MAb35 is more favorable than its radioiodine-labeled counterpart for RIT of colorectal carcinoma due to higher tumor-to-blood ratios, but the problem of nonspecific liver and bowel uptake must first be overcome. The absolute accumulation of activity in tumor remains low, however, so the probability of cure with this compound alone is questionable. The use of 67Cu as one component of a multimodality adjuvant treatment seems to remain the most appropriate application for RIT.

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Systematic pig slurry application to crop soils may lead to the accumulation of heavy metals in regions with intensive pig raising. The aim of this study was to evaluate the accumulation of Cu, Zn and Mn in soils under systematic pig slurry application. For this purpose, soil samples were collected from two of the most representative watersheds of Santa Catarina where the predominant activity is pig raising. In each watershed, 12 properties were chosen to evaluate the different systems of pig husbandry (complete cycle (CC), farrowing (FaU) and finishing units (FiU)). Based on information of the producers, soil samples were collected in areas with and without systematic manure application. To determine the total Cu, Zn and Mn content in soils and manure, a methodology proposed by the Environmental Protection Agency of the United States (USEPA), method nº 3050B, was used. For the available heavy metal content, Cu and Zn was extracted with HCl 0.1 mol L-1 and Mn with KCl 1 mol L-1. Data were subjected to multivariate analysis, using the canonical discriminant analysis to identify the metals that best differentiate the soils studied within each swine housing system. Successive pig slurry applications cause an increase in Cu, Zn and Mn availability in the soil and this indicates the need for monitoring of the metal concentrations over time. The critical values of Cu in the soil can be reached and exceeded more rapidly than Zn. The results showed that the soil type may be one of the attribute underlying the determination of public policies in pig raising and waste management because soils such as Inceptisols were shown to be more prone to possible contamination since they may more rapidly reach total critical Cu levels.

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Anthropogenic emissions of metals from sources such as smelters are an international problem, but there is limited published information on emissions from Australian smelters. The objective of this study was to investigate the regional distribution of heavy metals in soils in the vicinity of the industrial complex of Port Kembla, NSW, Australia, which comprises a copper smelter, steelworks and associated industries. Soil samples (n=25) were collected at the depths of 0-5 and 5-20 cm, air dried and sieved to < 2 mm. Aqua regia extractable amounts of As, Cr, Cu, Ph and Zn were analysed by inductively coupled plasma mass spectrometry (lCP-MS) and inductively coupled plasma atomic emission spectrometry (ICP-AES). Outliers were identified from background levels by statistical methods. Mean background levels at a depth of 0-5 cm were estimated at 3.2 mg/kg As, 12 mg/kg Cr, 49 mg/kg Cu, 20 mg/kg Ph and 42 mg/kg Zn. Outliers for elevated As and Cu values were mainly present within 4 km from the Port Kembla industrial complex, but high Ph at two sites and high Zn concentrations were found at six sites up to 23 km from Port Kembla. Chromium concentrations were not anomalous close to the industrial complex. There was no significant difference of metal concentrations at depths of 0-5 and 5-20 cm, except for Ph and Zn. Copper and As concentrations in the soils are probably related to the concentrations in the parent rock. From this investigation, the extent of the contamination emanating from the Port Kembla industrial complex is limited to 1-13 km, but most likely <4 km, depending on the element; the contamination at the greater distance may not originate from the industrial complex. (C) 2003 Elsevier B.V. All rights reserved.

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The aims of this study were to evaluate the effectiveness of diquat, copper hydroxide, copper oxychloride and their associations diquat + 0.1% copper oxychloride and diquat + 0.1% copper hydroxide to control Cerathophyllum demersum. Therefore, the concentrations used were 0.1, 0.3, 0.5, 0.7, 1.0 and 1.5 mg L-1 oxychloride and copper hydroxide and 0.2, 0.4, 0.8 and 1.2 mg L-1 diquat and their associations with 0.1% copper oxychloride and 0.1% copper and a control hydroxide. The experimental design was completely randomized with ten replications for 45 days. For evaluation we used a scale of 0-100% control of notes and rated the weight (g) and length (cm) of pointers at the end of the trial period. Diquat showed 100% efficacy at 30 DAA, associations in 21 DAA and copper sources promoted regrowth of C. demersum. Diquat and its associations were more effective in controlling C. demersum. The use of herbicide in combination with a copper source is more efficient for the control of submerged weeds because it potentiates the effect of the herbicide in weed control

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This master’s thesis investigates the significant macroeconomic and firm level determinants of CAPEX in Russian oil and mining sectors. It also studies the Russian oil and mining sectors, its development, characteristics and current situation. The panel data methodology was implemented to identify the determinants of CAPEX in Russian oil and mining sectors and to test derived hypotheses. The core sample consists of annual financial data of 45 publicly listed Russian oil and mining sector companies. The timeframe of the thesis research is a six year period from 2007 to 2013. The findings of the master’s thesis have shown that Gross Sales, Return On Assets, Free Cash Flow and Long Term Debt are firm level performance variables along with Russian GDP, Export, Urals and the Reserve Fund are macroeconomic variables that determine the magnitude of new capital expenditures reported by publicly listed Russian oil and mining sector companies. These results are not controversial to the previous research paper, indeed they confirm them. Furthermore, the findings from the emerging countries, such as Malaysia, India and Portugal, are analogous to Russia. The empirical research is edifying and novel. Findings from this master’s thesis are highly valuable for the scientific community, especially, for researchers who investigate the determinant of CAPEX in developing countries. Moreover, the results can be utilized as a cogent argument, when companies and investors are doing strategic decisions, considering the Russian oil and mining sectors.

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Two flavors of cookies were developed (savory and peppery) containing a mixture of plants such as "guaraná" (Paullinia cupana) and "catuaba" (Anemopaegma mirandum). A test of acceptance and buying intention was applied to 48 consumers through a structured hedonic scale of 9 points. Afterwards, the centesimal compositions of these cookies were obtained as well as their total contents of copper, iron, and zinc through the method of atomic absorption spectrometry with flame. Sensorial tests indicated that the cookies presented good acceptance with potential to sensorial growth. The amount of fibers in the samples, 3 g/100 g, surpassed expectations since the product was not invented with the intention of being a source of this nutrient. The total amount of copper (0.41 mg.100 g-1), iron (4.50 mg.100 g-1), and zinc (1.32 mg.100 g-1) was considered good. The cookies produced can be considered good sources of fibers, copper, iron, and zinc. Furthermore, they are beneficial to people affected by celiac disease because they lack gluten. They also present functional properties. In addition, the medicinal plants used are considered energetic.