Composição química da precipitação atmosférica no sul do Brasil: estudo preliminar

The present work is a preliminary study of total and wet precipitation in the Candiota region, RS. The samples were collected from January to June 2001 at four different sites. The following variables were analysed: pH, conductivity, alkalinity, Cl-, NO3-, F-, SO4(2-), Na+, K+, Mg2+, NH4+, Ca2+ and Zn, Cu, Fe, Al, Mn. The results showed slightly acidic precipitation and higher concentrations of NH4+, Na+, Cl- and SO4(2-). Factor analysis applied to the variables studied allowed identifying the major sources. Na+, Cl- and Mg2+ have their origin in sea salts and NH4+, Ca2+, K+, SO4(2-) and NO3- are from local anthropogenic sources.

Composição química da chuva e aporte atmosférico na Ilha Grande, RJ

Wet (n = 21) and dry (n = 23) deposition samples were collected from March to September 2002 at the southern coast of Ilha Grande. Rainwater pH varied from 4.3 to 6.3 and ionic concentrations (in µmol L-1) decreased in the order Cl- > Na+ > Mg2+ > SO4(2-) > NO3- ~ NH4+ > K+ ~ H+ > Ca2+. Scavenging of sea-salt aerosols was the major source of Cl-, Na+, Mg2+, and Ca2+. Half of total SO4(2-) was non-sea-salt SO4(2-). Total deposition fluxes of NH4+, NO3-, and non-sea-salt SO4(2-) were respectively 9.3, 17.8, and 16.0 mol ha-1 month-1.

3,4-Methylenedioxymethamphetamine enhances kainic acid convulsive susceptibility

Abstract Kainic acid (KA) causes seizures and neuronal loss in the hippocampus. The present study investigated whether a recreational schedule of 3,4-methylenedioxymethamphetamine (MDMA) favours the development of a seizure state in a model of KA-induced epilepsy and potentiates the toxicity profile of KA (20 or 30 mg/kg). Adolescent male C57BL/6 mice received saline or MDMA t.i.d. (s.c. every 3 h), on 1 day a week, for 4 consecutive weeks. Twenty-four hours after the last MDMA exposure, the animals were injected with saline or KA (20 or 30 mg/kg). After this injection, we evaluated seizures, hippocampal neuronal cell death, microgliosis, astrogliosis, and calcium binding proteins. MDMA pretreatment, by itself, did not induce neuronal damage but increased seizure susceptibility in all KA treatments and potentiated the presence of Fluoro-Jade-positive cells in CA1. Furthermore, MDMA, like KA, significantly decreased parvalbumin levels in CA1 and dentate gyrus, where it potentiated the effects of KA. The amphetamine derivative also promoted a transient decrease in calbindin and calretinin levels, indicative of an abnormal neuronal discharge. In addition, treatment of cortical neurons with MDMA (1050 μM) for 6 or 48 h significantly increased basal Ca2 +, reduced basal Na+ levels and potentiated kainate response. These results indicate that MDMA potentiates KA-induced neurodegeneration and also increases KA seizure susceptibility. The mechanism proposed includes changes in Calcium Binding Proteins expression, probably due to the disruption of intracellular ionic homeostasis, or/and an indirect effect through glutamate release.

3,4-Methylenedioxymethamphetamine enhances kainic acid convulsive susceptibility

Abstract Kainic acid (KA) causes seizures and neuronal loss in the hippocampus. The present study investigated whether a recreational schedule of 3,4-methylenedioxymethamphetamine (MDMA) favours the development of a seizure state in a model of KA-induced epilepsy and potentiates the toxicity profile of KA (20 or 30 mg/kg). Adolescent male C57BL/6 mice received saline or MDMA t.i.d. (s.c. every 3 h), on 1 day a week, for 4 consecutive weeks. Twenty-four hours after the last MDMA exposure, the animals were injected with saline or KA (20 or 30 mg/kg). After this injection, we evaluated seizures, hippocampal neuronal cell death, microgliosis, astrogliosis, and calcium binding proteins. MDMA pretreatment, by itself, did not induce neuronal damage but increased seizure susceptibility in all KA treatments and potentiated the presence of Fluoro-Jade-positive cells in CA1. Furthermore, MDMA, like KA, significantly decreased parvalbumin levels in CA1 and dentate gyrus, where it potentiated the effects of KA. The amphetamine derivative also promoted a transient decrease in calbindin and calretinin levels, indicative of an abnormal neuronal discharge. In addition, treatment of cortical neurons with MDMA (1050 μM) for 6 or 48 h significantly increased basal Ca2 +, reduced basal Na+ levels and potentiated kainate response. These results indicate that MDMA potentiates KA-induced neurodegeneration and also increases KA seizure susceptibility. The mechanism proposed includes changes in Calcium Binding Proteins expression, probably due to the disruption of intracellular ionic homeostasis, or/and an indirect effect through glutamate release.

Expressional regulation of key hepatic enzymes of intermediary metabolism in European seabass (Dicentrarchus labrax) during food deprivation and refeeding

We hypothesized that the analysis of mRNA level and activity of key enzymes in amino acid and carbohydrate metabolism in a feeding/fasting/refeeding setting could improve our understanding of how a carnivorous fish, like the European seabass (Dicentrarchus labrax), responds to changes in dietary intake at the hepatic level. To this end cDNA fragments encoding genes for cytosolic and mitochondrial alanine aminotransferase (cALT; mALT), pyruvate kinase (PK), glucose 6-phosphate dehydrogenase (G6PDH) and 6-phosphogluconate dehydrogenase (6PGDH) were cloned and sequenced. Measurement of mRNA levels through quantitative real-time PCR performed in livers of fasted seabass revealed a significant increase in cALT (8.5-fold induction)while promoting a drastic 45-fold down-regulation of PK in relation to the levels found in fed seabass. These observations were corroborated by enzyme activity meaning that during food deprivation an increase in the capacity of pyruvate generation happened via alanine to offset the reduction in pyruvate derived via glycolysis. After a 3-day refeeding period cALT returned to control levels while PK was not able to rebound. No alterations were detected in the expression levels of G6PDH while 6PGDH was revealed to be more sensitive specially to fasting, as confirmed by a significant 5.7-fold decrease in mRNA levels with no recovery after refeeding. Our results indicate that in early stages of refeeding, the liver prioritized the restoration of systemic normoglycemia and replenishment of hepatic glycogen. In a later stage, once regular feeding is re-established, dietary fuel may then be channeled to glycolysis and de novo lipogenesis.

Expressional regulation of key hepatic enzymes of intermediary metabolism in European seabass (Dicentrarchus labrax) during food deprivation and refeeding

We hypothesized that the analysis of mRNA level and activity of key enzymes in amino acid and carbohydrate metabolism in a feeding/fasting/refeeding setting could improve our understanding of how a carnivorous fish, like the European seabass (Dicentrarchus labrax), responds to changes in dietary intake at the hepatic level. To this end cDNA fragments encoding genes for cytosolic and mitochondrial alanine aminotransferase (cALT; mALT), pyruvate kinase (PK), glucose 6-phosphate dehydrogenase (G6PDH) and 6-phosphogluconate dehydrogenase (6PGDH) were cloned and sequenced. Measurement of mRNA levels through quantitative real-time PCR performed in livers of fasted seabass revealed a significant increase in cALT (8.5-fold induction)while promoting a drastic 45-fold down-regulation of PK in relation to the levels found in fed seabass. These observations were corroborated by enzyme activity meaning that during food deprivation an increase in the capacity of pyruvate generation happened via alanine to offset the reduction in pyruvate derived via glycolysis. After a 3-day refeeding period cALT returned to control levels while PK was not able to rebound. No alterations were detected in the expression levels of G6PDH while 6PGDH was revealed to be more sensitive specially to fasting, as confirmed by a significant 5.7-fold decrease in mRNA levels with no recovery after refeeding. Our results indicate that in early stages of refeeding, the liver prioritized the restoration of systemic normoglycemia and replenishment of hepatic glycogen. In a later stage, once regular feeding is re-established, dietary fuel may then be channeled to glycolysis and de novo lipogenesis.

Efeitos dos escoamentos urbanos e rurais na qualidade das águas do córrego verruga em vitória da conquista - Bahia, Brasil

This study examined the spatial and temporal variations of 13 physico-chemical parameters in water and sediment samples collected along the rural and urban section of Verruga Stream. The metal concentrations were determined by FAAS. The conductivity and the concentration of Na+, Cl-, and Ca2+ showed the largest variations in the urban area demonstrating that these parameters are appropriate indicators of urban contamination. The application of cluster and principal component analysis showed that the Cd2+ and Mn2+ are associated with the use of fertilizers in the rural area.

Avaliação de metais traços e íons majoritários em águas de chuva na cidade de São Paulo

Rainfall samples collected in the downtown area of São Paulo city, during 2003, exhibited average concentrations of cadmium, lead and copper of 1.33, 8.52 and 49.5 nmol L-1, respectively. Among the major ions, NH4+ was the predominant species followed by NO3-, SO4(2-) and Ca2+, with volume weighed mean (VWM) concentrations of 37.1, 20.1, 11.9 and 10.8 µmol L-1, respectively. All the determined species showed high inter-events variability, including free H+ ions whose VWM concentration was 4.03 µmol L-1, corresponding to a pH value of 5.39.

Parâmetros indicativos do processo de salinização em rios urbanos do semi-árido brasileiro

This study examined the spatial and temporal variations of six important parameters of the salt accumulation process in water samples collected along section urban of Contas River. The Na+, K+, Ca2+ and Mg2+ concentrations were determined by FAAS. The conductivity, total dissolved solids, Na+ and Ca2+ presented the largest seasonal and spatial variations in the urban area demonstrated that are appropriate indicators of urban contamination. The readily soluble salts in drainage urban, contribute for the degradation of the water of rivers located in semi-arid zones.

Estudo de sorção de herbicidas pelos argilominerais vermiculita e montmorilonita

The clay minerals montmorillonite (MT) and vermiculite (VT), previously treated with Ca2+, K+ and Na+, were employed in a sorption study with herbicides. The herbicides 2,4-D, diuron, alachlor and metolachlor showed no interaction with MT and VT. On the other hand, the triazines presented a good sorption process, close to 100% for ametrine removal and near to 56 and 69% for atrazine and simazine, respectively, by MT. These results suggest that the MT specie may be a good material for triazines removal from aqueous medium and an alternative phase to preconcentration process, besides to exhibit a good selectivity.

Composição química das águas pluviais e deposição atmosférica anual na bacia do Alto Sorocaba (SP)

Two sampling points were chosen and forty samples were collected between January and December 2006 at Alto Sorocaba basin. The rainwater pH varied from 5.46 to 6.36 (Ibiúna) and 5.26 to 6.81 (Itupararanga), being Ca2+ the main ion responsible for controlling the rainwater pH. The ionic concentrations decreased in the following order: Ca2 +>Na+> Mg2+>K+ for cations and SO4(2-)>HCO3->NO 3->Cl- >PO4(3-) for anions. The annual atmospheric deposition appeared to be controlled mostly by following sources: mining activities and cement factories (Ca2+ and HCO3-), natural soil dust (Na+, Mg2+ and HCO3-), fossil fuel burning (SO4(2-)) and agriculture activities (K+, NO3- and PO4(3-)).

Composição química da precipitação úmida da região metropolitana de Porto Alegre, Brasil, 2005- 2007

This work aims to quantify the wet precipitation the Metropolitan Area of Porto Alegre (MAPA), in southern Brazil, through the analysis of major ions (by ion chromatography) and metallic elements (ICP/AES). By principal components analysis and cluster analysis was possible to identify the influence of natural and anthropic sources in wet precipitation. The results indicated of the higher contribution to the ions NH4+, SO4(2-) and Ca2+. Thus it was possible to identify the contribution of anthropogenic sources in wet precipitation in the study area, such as power plants, oil refineries, steel and vehicle emissions.

Assessment of hydrochemical quality of ground water under some urban areas within sana'a secreteriat

Groundwater from nine wells of three different districts, located at Sana'a secretariat was analyzed for hydrochemical quality assessment. Measurements of water quality parameters including pH, EC, CO3(2-), HCO3-, Cl-, NO3-, SO4(2-), Ca2+, Mg2+, Fe3+, K+, and Na+ were carried out . Classification of the groundwater samples according to Cl, SO4(2-), CO3(2-) and HCO3-, hardness (H), total dissolved solids (TDS), base-exchange, and meteoric genesis was demonstrated. Suitability of ground water samples for irrigation and industrial uses according to sodium adsorption ration (SAR), ratio of dissolved sodium (RDS), residual sodium carbonate (RSC) and saturation index (SI) was also investigated. The results of this study showed that almost all ground water samples were of good quality that makes them suitable for drinking and domestic uses. Results also indicated that even though some of the ground water samples were suitable for irrigation purposes, almost all of them were found not be good for industrial uses. Despite all drawbacks of the sewerage system built around Sana'a secretariat at the beginning of the first decade of the third millennium, the results of this study indicate that there is scope of significant improvement in Sana'a secretariat ground water quality.

Determination of sugars and organic acids in pulp samples by capillary electrophoresis with UV detection

This MSc work was done in the project of BIOMECON financed by Tekes. The prime target of the research was, to develop methods for separation and determination of carbohydrates (sugars), sugar acids and alcohols, and some other organic acids in hydrolyzed pulp samples by capillary electrophoresis (CE) using UV detection. Aspen, spruce, and birch pulps are commonly used for production of papers in Finland. Feedstock components in pulp predominantly consist of carbohydrates, organic acids, lignin, extractives, and proteins. Here in this study, pulps have been hydrolyzed in analytical chemistry laboratories of UPM Company and Lappeenranta University in order to convert them into sugars, acids, alcohols, and organic acids. Foremost objective of this study was to quantify and identify the main and by-products in the pulp samples. For the method development and optimization, increased precision in capillary electrophoresis was accomplished by calculating calibration data of 16 analytes such as D-(-)-fructose, D(+)-xylose, D(+)-mannose, D(+)-cellobiose, D-(+)-glucose, D-(+)-raffinose, D(-)-mannitol, sorbitol, rhamnose, sucrose, xylitol, galactose, maltose, arabinose, ribose, and, α-lactose monohydratesugars and 16 organic acids such as D-glucuronic, oxalic, acetic, propionic, formic, glycolic, malonic, maleic, citric, L-glutamic, tartaric, succinic, adipic, ascorbic, galacturonic, and glyoxylic acid. In carbohydrate and polyalcohol analyses, the experiments with CE coupled to direct UV detection and positive separation polarity was performed in 36 mM disodium hydrogen phosphate electrolyte solution. For acid analyses, CE coupled indirect UV detection, using negative polarity, and electrolyte solution made of 2,3 pyridinedicarboxylic acid, Ca2+ salt, Mg2+ salts, and myristyltrimethylammonium hydroxide in water was used. Under optimized conditions, limits of detection, relative standard deviations and correlation coefficients of each compound were measured. The optimized conditions were used for the identification and quantification of carbohydrates and acids produced by hydrolyses of pulp. The concentrations of the analytes varied between 1 mg – 0.138 g in liter hydrolysate.

Impactos de sistemas agroflorestais e convencional sobre a qualidade do solo no semi-árido cearense

Os benefícios gerados pelos sistemas agroflorestais (SAFs) ao ambiente são comprovados nas mais diversas regiões do mundo. No entanto, na região semi-árida cearense, são poucos os trabalhos desenvolvidos englobando as vantagens atribuídas a este tipo de sistema quanto ao uso do solo. Objetivou-se avaliar o impacto de quatro SAFs e um convencional sobre a qualidade do solo, comparativamente à condição natural (caatinga nativa), após cinco anos de uso na região semi-árida cearense. Os tratamentos testados foram: agrossilvipastoril (AGP); silvipastoril (SILV); tradicional cultivado em 1998 e 1999 (TR98); tradicional cultivado em 2002 (TR02); e cultivo intensivo (CI) e duas áreas de mata nativa (MN-1 e MN-2), que foram usadas como referência de um estado de equilíbrio. O impacto dos sistemas de manejo sobre a qualidade do solo foi medido pelas seguintes variáveis: a granulometria; argila dispersa; a estabilidade e distribuição porcentual dos agregados; os teores de Ca2+, Mg2+, K+, Na+ trocáveis; a acidez potencial; o pH do solo; e o teor de carbono orgânico total (COT), considerando-se as profundidades de 0-6, 6-12, 12-20 e 20-40 cm. Os tratamentos AGP, TR98 e CI promoveram maior revolvimento do solo provocando a redução nos teores de COT. Os atributos químicos, como bases trocáveis, capacidade de troca catiônica, pH e acidez potencial nos tratamentos SILV e MN-2, variaram em função dos teores de argila, enquanto nos tratamentos TR98 e CI a redução nesses atributos foi devido ao maior revolvimento do solo. O tratamento AGP mostrou-se eficiente na ciclagem de nutrientes, entretanto, o revolvimento do solo e a concomitante redução do teor de COT, geraram também diminuição na estabilidade de agregados. Os resultados obtidos permitem recomendar o tratamento SILV para a manutenção da qualidade do solo e produção de alimentos na região do semi-árido cearense.