Study of copper electrodeposition mechanism from a strike alkaline bath prepared with 1-hydroxyethane-1,1-diphosphonic acid through cyclic voltammetry technique

Copper strike baths are extensively used in metal plating industry as they present the ability to plate adherent copper layers on less-noble metal substrates such as steel and zinc die castings. However, in the last few years, due to environmental controls and safety policies for operators, the plating industry has been interested in replacing the toxic cyanide copper strike baths with environmentally friendly baths. A broad bibliographic review showed that the published papers, referring to the new nontoxic copper strike baths, are patents, having little or no emphasis focused on electrodeposition mechanisms. Therefore, it was decided to study the copper electrodeposition mechanism from a strike alkaline bath prepared with one of the most nontoxic chelating agents cited in many patents which is the 1-hydroxyethane-1,1-diphosphonic acid, known as HEDP. This acid forms very stable water soluble complexes with Cu(2+) ions, thus cupric sulfate was used for preparing the plating bath. The results obtained through a cyclic voltammetry technique showed that Cu(2+) ion reduction to Cu from an HEDP electrodeposition bath occurs via a direct reduction reaction without a formation of Cu(+) intermediates. (C) 2010 Elsevier Ltd. All rights reserved.

Chemical-mineralogical characterization of C&D waste recycled aggregates from Sao Paulo, Brazil

This study presents a methodology for the characterization of construction and demolition (C&D) waste recycled aggregates based on a combination of analytical techniques (X-ray fluorescence (XRF), soluble ions, semi-quantitative X-ray diffraction (XRD), thermogravimetric analysis (TCA-DTG) and hydrochloric acid (HCl) selective dissolution). These combined analytical techniques allow for the estimation of the amount of cement paste, its most important hydrated and carbonated phases, as well as the amount of clay and micas. Details of the methodology are presented here and the results of three representative C&D samples taken from the Sao Paulo region in Brazil are discussed. Chemical compositions of mixed C&D aggregate samples have mostly been influenced by particle size rather than the visual classification of C&D into red or grey and geographical origin. The amount of measured soluble salts in C&D aggregates (0.15-25.4 mm) is lower than the usual limits for mortar and concrete production. The content of porous cement paste in the C&D aggregates is around 19.3% (w/w). However, this content is significantly lower than the 43% detected for the C&D powders (< 0.15 min). The clay content of the powders was also high, potentially resulting from soil intermixed with the C&D waste, as well as poorly burnt red ceramic. Since only about 50% of the measured CaO is combined with CO(2), the powders have potential use as raw materials for the cement industry. (C) 2008 Elsevier Ltd. All rights reserved.

Influence of Redox Environments on the Solubility of Arsenic in Soils

Arsenic (As) is a semimetallic element that is notorious for its toxicity and carcinogenicity. Arsenic can be removed by some ferns. The objectives of this study were to investigate the ability of Pteris vittata L. (Pteridophyta) and Phlebodium aureum (L.) J. Sm. (Polypodiaceae) to absorb inorganic As, in the form of arsenate and arsenite. The removal of As by ferns was observed at varying anion concentrations and As solubility in the absorbing plant. Results obtained with ferns on As-contaminated soil indicate that redox potential and iron (Fe) presence affected the solubility of As and the absorption capacity of ferns. Upon reduction to -200mV, the soluble As content increased to 400mV. The results indicate that Fe oxides and the influence of redox potential strongly affect As absorption. Under nonreducing conditions, Phlebodium aureum did not remove As as well as Pteris vittata. Under more reducing conditions (-200 to 0mV) and under similar soil conditions, the results show that the both ferns remove As.

QUALITY EVALUATION OF MINIMALLY PROCESSED `REGIS` PEACH

The aim of this work was evaluate the effect of citric acid at 1% and 2% in the maintenance of the quality of minimally processed `Regis` peaches, during 9 days storage under refrigeration (5+/-1 degrees C, 85-87% RU) and passive modified atmospheres. The following analyses were realized: color, firmness, texture, soluble solids, titratable acidity, pH, CO(2) and O(2). Increasing in a value and decreasing in b and L values on minimally processed peaches were observed, independent of the citric acid treatment, indicating a browning on the product mainly on the 9(th) day of storage. Overall, the levels of titratable acidity and pH changed at the storage period and at the concentrations studied, unlike the content of soluble solids that remained unchanged. The texture, CO(2) and O(2) changed only for the storage period unlike texture that was higher with the treatment of citric acid 2%. It can be concluded that neither tested concentration of citric acid was effective in preventing enzymatic browning of minimally processed peaches stored the 5+/-1 degrees C and 85-87% RU and passive modified atmosphere.

Microencapsulation of propolis extract by complex coacervation

The propolis has potential to be a natural food additive However its application is limited because It is alcohol-soluble and has strong flavour Microencapsulation may be an alternative for reducing these problems The aim of this study was to encapsulate propolis extract by complex coacervation using isolated soy protein and pectin as encapsulant agents The coacervation was studied as a function of pH (5 0 4 5 4 0 and 3 5) and the concentration of encapsulants and core (2 5 and 5 0 g/100 mL) Samples obtained at pH 4 0 in both concentrations were lyophilized and analyzed for hygroscopicity encapsulation efficiency particle size morphology thermal behavior stability of phenolic and flavonoids during storage as well as antioxidant and antimicrobial activities It was possible to encapsulate propolis extract by complex coacervation and to obtain it in the form of powder alcohol-free stable with antioxidant property antimicrobial activity against Staphylococcus aureus and with the possibility of controlled release in foods (C) 2010 Elsevier Ltd All rights reserved

Photochemical damage and comparative performance of superoxide dismutase and ascorbate peroxidase in sugarcane leaves exposed to paraquat-induced oxidative stress

The physiological responses of sugarcane (Succharion officinarum L.) to oxidative stress induced by methyl viologen (paraquat) were examined with respect to photochemical activity, chlorophyll content, lipid peroxidation and superoxide dismutase (SOD) and ascorbate peroxidase (APX) activities. Thirty-day-old sugarcane plants were sprayed with 0, 2, 4, 6 and 8 mM methyl viologen (MV). Chlorophyll fluorescence was measured after 18 It and biochemical analyses were performed after 24 and 48 h. Concentrations of MV above 2 mM caused significant damage to photosystem II (PSII) activity. Potential and effective quantum efficiency of PSII and apparent electron transport rate were greatly reduced or practically abolished. Both chlorophyll and soluble protein contents steadily decreased with MV concentrations above 2 mM after 24 It of exposure, which became more pronounced after 48 It, achieving a 3-fold decrease. Insoluble protein contents were little affected by MV. Oxidative stress induced by MV was evidenced by increases in lipid peroxidation. Specific activity of SOD increased, even after 48 h of exposure to the highest concentrations of MV, but total activity on a fresh weight basis did not change significantly. Nondenaturing YAGE assayed with H2O2 and KCN showed that treatment with MV did not change Cu/Zn-SOD and MnSOD isoform activities. In contrast, APX specific activity increased at 2 mM MV but then dropped at higher doses. Oxidative damage induced by MV was inversely related to APX activity. It is suggested that the major MV-induced oxidative damages in sugarcane leaves were related to excess H2O2, probably in chloroplasts, caused by an imbalance between SOD and APX activities, in which APX was a limiting step. Reduced photochemical activity allowed the early detection of the ensuing oxidative stress. (c) 2007 Elsevier Inc. All rights reserved.

Postharvest diseases in citrus and characterization of the fungal population in Sao Paulo`s wholesale market

The purposes of this workwere to characterize postharvest injuries and to evaluate the physicochemical characteristics of`Nra` and `Lima`oranges and `Murcott` tangor at Ceagesp market, as well as to characterize the environmental mycoflora in retail points at Ceagesp in 2006. Fruits collected at retail points were stored for 14 days at 25 degrees C and 85-90% RH. The incidence of injuries was visually evaluated every three days. The physicochemical characteristics analyzed were titratable acidity and soluble solids amount. The environmental mycoflora was sampled according to the gravimetric method, using Petri dishes containing potato-dextrose-agar medium+pentabiotic opened for two minutes. The average rot incidences in `Pera` and `Lima` oranges and `Murcott` tangor were 12.8, 14.9 and 25.8%, respectively, at the end of the storage period, and green mold was the main postharvest disease. Associations between physicochemical parameters and rot incidence was, in general, not significant. The environmental fungal population varied significantly between the sampling months in retail points with an average of 25.3 cfu/plate. Penicillium and Cladosporium were the most recorded genera of fungi. Positive correlation (r=0.96) was observed between frequency of P digitatum found in the environment of retail points and the green mold in on-sale fruits of `Pera` orange. However, for `Lima` orange and `Murcott` tangor such a correlation was not verified.

Zn uptake, physiological response and stress attenuation in mycorrhizal jack bean growing in soil with increasing Zn concentrations

The influence of arbuscular mycorrhizal fungi (AMF) inoculation on Canavalia ensiformis growth. nutrient and Zn uptake, and on some physiological parameters in response to increasing soil Zn concentrations was studied. Treatments were applied in seven replicates in a 2 x 4 factorial design, consisting of the inoculation or not with the AMF Glomus etunicatum, and the addition of Zn to soil at the concentrations of 0, 100, 300 and 900 mg kg(-1). AMF inoculation enhanced the accumulation of Zn in tissues and promoted biomass yields and root nodulation. Mycorrhizal plants exhibited relative tolerance to Zn up to 300 mg kg(-1) without exhibiting visual symptoms of toxicity, in contrast to non-mycorrhizal plants which exhibited a significant growth reduction at the same soil Zn concentration. The highest concentration of Zn added to soil was highly toxic to the plants. Leaves of plants grown in high Zn concentration exhibited a Zn-induced proline accumulation and also an increase in soluble amino acid contents; however proline contents were lower in mycorrhizal jack beans. Plants in association or not with the AMF exhibited marked differences in the foliar soluble amino acid profile and composition in response to Zn addition to soil. In general, Zn induced oxidative stress which could be verified by increased lipid peroxidation rates and changes in catalase, ascorbate peroxidase, glutathione reductase and superoxide dismutase activities. In summary, G. etunicatum was able to maintain an efficient symbiosis with jack bean plants in moderately contaminated Zn-soils, improving plant performance under those conditions, which is likely to be due to a combination of physiological and nutritional changes caused by the intimate relation between fungus and plant. The enhanced Zn uptake by AMF inoculated jack bean plants might be of interest for phytoremediation purposes. (C) 2009 Elsevier Ltd. All rights reserved.

Biochemical responses of glyphosate resistant and susceptible soybean plants exposed to glyphosate

Glyphosate is a wide spectrum, non-selective, post-emergence herbicide. It acts on the shikimic acid pathway inhibiting 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS), thus obstructing the synthesis of tryptophan, phenylalanine, tyrosine and other secondary products, leading to plant death. Transgenic glyphosate-resistant (GR) soybean [Glycine max (L.)] expressing an glyphosate-insensitive EPSPS enzyme has provided new opportunities for weed control in soybean production. The effect of glyphosate application on chlorophyll level, lipid peroxidation, catalase (CAT), ascorbate peroxidase (APX), guaiacol peroxidase (GOPX) and superoxide dismutase (SOD) activities, soluble amino acid levels and protein profile, in leaves and roots, was examined in two conventional (non-GR) and two transgenic (GR) soybean. Glyphosate treatment had no significant impact on lipid peroxidation, whilst the chlorophyll content decreased in only one non-GR cultivar. However, there was a significant increase in the levels of soluble amino acid in roots and leaves, more so in non-GR than in GR soybean cultivars. Root CAT activity increased in non-GR cultivars and was not altered in GR cultivars. In leaves, CAT activity was inhibited in one non-GR and one GR cultivar. GOPX activity increased in one GR cultivar and in both non-GR cultivars. Root APX activity increased in one GR cultivar. The soluble protein profiles as assessed by 1-D gel electrophoresis of selected non-GR and GR soybean lines were unaffected by glyphosate treatment. Neither was formation of new isoenzymes of SOD and CAT observed when these lines were treated by glyphosate. The slight oxidative stress generated by glyphosate has no relevance to plant mortality. The potential antioxidant action of soluble amino acids may be responsible for the lack of lipid peroxidation observed. CAT activity in the roots and soluble amino acids in the leaves can be used as indicators of glyphosate resistance.

Lysine biosynthesis and nitrogen metabolism in quinoa (Chenopodium quinoa): Study of enzymes and nitrogen-containing compounds

Aspartate kinase (AK, EC 2.7.2.4), homoserine dehydrogenase (HSDH, EC 1.1.1.3) and dihydrodipicolinate synthase (DHDPS, EC 4.2.1.52) were isolated and partially purified from immature Chenopodium quinoa Willd seeds. Enzyme activities were studied in the presence of the aspartate-derived amino acids lysine, threonine and methionine and also the lysine analogue S-2-aminoethyl-L-cysteine (AEC), at 1 mM and 5 mM. The results confirmed the existence of, at least, two AK isoenzymes, one inhibited by lysine and the other inhibited by threonine, the latter being predominant in quinoa seeds. HSDH activity was also shown to be partially inhibited by threonine, whereas some of the activity was resistant to the inhibitory effect, indicating the presence of two isoenzymes, one resistant and another sensitive to threonine inhibition. Only one DHDPS isoenzyme highly sensitive to lysine inhibition was detected. The results suggest that the high concentration of lysine observed in quinoa seeds is possibly due to a combined effect of increased lysine, synthesis and accumulation in the soluble form and/or as protein lysine. Nitrogen assimilation was also investigated and based on nitrate content, nitrate reductase activity, amino acid distribution and ureide content, the leaves were identified as the predominant site of nitrate reduction in this plant species. The amino acid profile analysis in leaves and roots also indicated an important role of soluble glutamine as a nitrogen transporting compound. (c) 2007 Elsevier Masson SAS. All rights reserved.

Nutritional Quality of Sorghum Seeds: Storage Proteins and Amino Acids

One sorghum commercial genotype (MASSA 03) and nine ICRISAT high-lysine genotypes from India were analyzed for storage protein content, distribution profile, and soluble amino acid concentrations. Storage proteins fraction were extracted and separated by SDS-PAGE. Soluble amino acids contents were determined by HPLC. Variations in intensity and appearance and disappearance of protein bands were observed among the sorghum genotypes suggesting genetic variability. Amino acid profile also indicated large variations in the amino acid concentrations. The high lysine and threonine soluble concentrations observed in the seeds of the sorghum genotypes encouraged the use of these genotypes as potential food source due to the better balanced amino acids profile.

Tree performance and fruit yield and quality of `Okitsu` Satsuma mandarin grafted on 12 rootstocks

The citriculture in Brazil, as well as in other important regions in the world, is based on very few mandarin cultivars. This fact leads to a short harvest period and higher prices for off-season fruit. The `Okitsu` Satsuma (Citrus unshiu Marc.) is among the earliest ripening mandarin cultivars and it is considered to be tolerant to, citrus canker (Xanthomonas citri subsp. citri Schaad et al.) and to citrus variegated chlorosis (Xylella fastidiosa Wells et al.). Despite having regular fruit quality under hot climate conditions, the early fruit maturation and absence of seeds of `Okitsu` fruits are well suited for the local market in the summer(December through March), when the availability of citrus fruits for fresh consumption is limited. Yet, only a few studies have been conducted in Brazil on rootstocks for `Okitsu`. Consequently, a field trial was carried out in Bebeclouro, Sao Paulo State, to evaluate the horticultural performance of `Okitsu` Satsuma mandarin budded onto 12 rootstocks: the citrandarin `Changsha` mandarin (Citrus reticulata Blanco) x Poncirus trifoliata `English Small`: the hybrid Rangpur lime (Citrus limonia Osbeck) x `Swingle` citrumelo (P. trifoliata (L.) Raf. x Citrus paradisi Macfad.); the trifoliates (P. trifoliata (L) Raf)`Rubidoux`,`FCAV` and `Flying Dragon`(P. trifoliata var. monstrosa); the mandarins `Sun Chu Sha Kat`(C. reticulata Blanco) and `Sunki`(Citrus sunki (Hayata) Hort. ex. Tanaka); the Rangpur limes (C. limonia Osbeck) `Cravo Limeira` and `Cravo FCAV`;`Carrizo` citrange (Citrus sinensis x P. trifoliata), `Swingle` citrumelo (P. trifoliata x C. paradisi), and `Orlando` tangelo (C. paradisi x Citrus tangerina cv. `Dancy`). The experimental grove was planted in 2001, using a 6 m x 3 m spacing, in a randomized block design. No supplementary irrigation was applied. Fruit yield, canopy volume, and fruit quality were assessed for each rootstock. A cluster multivariate analysis identified three different rootstock pairs with similar effects on plant growth, yield and fruit quality of `Okitsu` mandarin. The `Flying Dragon `trifoliate had a unique effect over the `Okitsu` trees performance, inducing lower canopy volume and higher yield efficiency and fruit quality, and might be suitable for high-density plantings. The `Cravo Limeira` and `Cravo FCAV` Rangpur limes induced early-ripening of fruits, with low fruit quality. `Sun Chu Sha Kat` and `Sunki` mandarins and the `Orlando` tangelo conferred lower yield efficiency and less content of soluble solids for the latter rootstock. (C) 2009 Elsevier B.V. All rights reserved.

Carbon and Nitrogen Dynamics in an Oxisol as Affected by Liming and Crop Residues under No-Till

The short-term effects of surface lime application and black oat (Avena strigosa Schreb.) residues, with or without N fertilization, were evaluated in a long-term no-till (NT) system on a sandy clay loam, a kaolinitic, thermic Typic Hapludox from the state of Parana, Brazil. The main plot treatments were: control and dolomitic lime applied on soil surface at 8 Mg ha(-1). Three treatments with crop residues were evaluated on the subplots: (i) fallow, (ii) black oat residues, and (iii) black oat residues aft er N fertilization at 180 kg ha(-1). Black oat dry biomass was not affected by the treatments during 3 yr. Surface liming increased soil pH, microbial biomass, microbial activity, and bacterial/fungal ratio at the soil surface (0-5 cm), resulting in increased amino acid turnover, water-soluble humic substances formation, and N mineralization and nitrification. While the application of black oat did increase the soil pH, overall it had much less effect on soil biological processes and C and N pools than did lime. We concluded that black oat cannot replace the need for lime to optimize crop production in these tropical NT systems. In the long term, however, black oat should aid in the amelioration of acidity and replenishment of soil organic C pools and should help reduce erosion. Overall, this study suggests that overapplication of inorganic fertilizer N may occur in some tropical NT systems. Further experiments are required in NT systems to investigate the use of slow-release N fertilizers in combination with lime and black oat as a mechanism to reduce acidification and promote sustainability.

Sodicity and salinity in a Brazilian Oxisol cultivated with sugarcane irrigated with wastewater

Changes in soil sodicity-salinity parameters are one of the most characteristic alterations after treated sewage effluent (TSE) irrigation in agro-systems. Considering the importance of these parameters for agricultural management, as well as the economical value of sugarcane for Brazil, the present study aimed at evaluating effects on soil sodicity and salinity under tropical conditions over 16 months of TSE irrigation in a sugarcane plantation at Lins, Sao Paulo State, Brazil. Soil samplings were carried out in February 2005 (before planting), December 2005 (after 8 months of TSE irrigation) and September 2006 (after 16 months of TSE irrigation) following a complete block design with four treatments and four replicates. Treatments consisted of. (i) control, without TSE irrigation; (ii) T100, T150 and T200, with TSE irrigation supplying 100% (0% surplus, total of 2524 mm), 150% (50% surplus, total of 3832 mm) and 200% (100% surplus, total of 5092 mm) of crop water demand, respectively. Compared to initial soil conditions, at the end of the experiment increases of exchangeable sodium (from 2.4 to 5.9 mmol(c) kg(-1)), exchangeable sodium percentage (ESP) (from 8 to 18%), soluble Na (from 1.4 to 4.7 mmol L(-1)) and sodium adsorption ratio (SAR) of soil solution (from 3.6 to 12.6 (mmol were found in the soil profile (0-100 cm) as an average for the irrigated plots due to high SAR of TSE. Associated with the increments were mostly significant increases in clay dispersion rates at depths 0-10, 10-20 and 20-40 cm. Electrical conductivity (EC) of soil solution increased during the TSE irrigation period whereas at the end of the experiment, after short term discontinuation of irrigation and harvest, EC in the topsoil (0-10 and 10-20 cm) decreased compared to the previous samplings. Moreover, despite increasing sodicity over time mainly insignificant differences within the different irrigated treatments were found in December 2005 and September 2006. This suggests that independent of varying irrigation amounts the increasing soil sodicity over time were rather caused by the continuous use of TSE than by its quantity applied. Moreover, also plant productivity showed no significant differences within the TSE irrigated plots. The study indicates that monitoring as well as remediation of soil after TSE irrigation is required for a sustainable TSE use in order to maintain agricultural quality parameters. (C) 2008 Elsevier B.V. All rights reserved.

Plant availability of phosphorus in four superphosphate fertilizers varying in water-insoluble phosphate compounds

There is concern that the use of lower quality phosphate rock can result in elevated amounts of Fe-Al-P water-insoluble compounds in fertilizers and, consequently, low agronomic effectiveness. Therefore, studies were conducted to evaluate the effect of some of these compounds on plant growth. Four commercial superphosphates varying in chemical composition (two single and two triple superphosphates) were selected for the study. Fertilizer impurities were collected as water-insoluble residues by washing each P source with deionized water. A modal analysis, based primarily on elemental chemical analysis and x-ray diffractometry, was used to estimate the chemical composition of each P source. Water-soluble monocalcium phosphate (MCP) and the water-leached fertilizer residues were prepared to give a range of fertilizers in terms of water-soluble phosphorus (WSP) (0-100% of the available P as MCP). The water-leached fractions, MCP, and the mixtures of MCP with water-leached fractions were applied to supply 40 mg available P kg(1) to a thermic Rhodic Kanhapludult with pH values of 5.2 +/- 0.05 (unlimed) and 6.4 +/- 0.08 (limed). Wheat (Triticum aestivum L.) grown in a greenhouse for 101 d served as the test crop. The requirement for WSP was source and pH dependent. At a soil pH of 5.2, the fertilizers required 73 to 95% WSP to reach the maximum dry-matter yield, while they required 60 to 86% WSP at pH 6.4. To reach 90% of the maximum yield, all superphosphate fertilizers required <50% WSP. These results show that it is not always necessary to have high water solubility as required by legislation in many countries.