Estudo do comportamento do chumbo em latossolos brasileiros tratados com fosfatos: contribui����es para a remedia����o de s��tios contaminados

Phosphates have been used for lead immobilization in soils but the influence of soil type is not fully understood. In this work, lead chemical behaviour in two Brazilian latosoils (LA and LV) was studied via treatment with phosphates. The Pb concentration in Toxicity Characteristic Leaching Procedure (TCLP) solutions was decreased in all treatments. After treatment with H3PO4 the Pb concentration in the LA remained within the regulatory limit established by EPA. The ecotoxicological results with Daphnia pulex showed that this treatment reduced the lead bioavailability. Sequential extraction analyses showed that the lead was transferred from the most available to the residual fraction. Relevant decrease of soluble lead was observed in all phosphate treatments.

Psychometric Properties of the Personal Wellbeing Index in Brazilian and Chilean Adolescents Including Spirituality and Religion = Propriedades Psicom��tricas do Personal Wellbeing Index em Adolescentes Brasileiros e Chilenos Incluindo Espiritualidade e Religi��o

This study compared the 7-item Personal Wellbeing Index (PWI) with two other versions which include the domains ���Spirituality��� and ���Religion���, separately, in a sample of Brazilian (n = 1.047) and Chilean (n = 1.053) adolescents. A comparison of psychometric properties between the PWI versions was carried out through multigroup confi rmatory factor analysis showing adequate adjustments (CFI > .95, RMSEA < .08), whereas the item spirituality presented better performance. For the analysis of the differential contribution of each domain to the notion of global satisfaction, a regression on the item Overall Life Satisfaction (OLS) was applied using structural equations. It isrecommended the inclusion of the item spirituality in the original scale, considering the importance of such domain in both cultures

Especia����o de cromo em cimentos e derivados de cimento brasileiros

A method for determination of Cr(III) and Cr(VI) in cement and cement-related materials was studied. Molecular absorption spectrophotometry based on 1,5-diphenylcarbazide as chromogenic reagent was used for determination of Cr(VI) after alkaline extraction. The total chromium concentration was determined using flame atomic absorption spectrometry (FAAS) after complete sample decomposition by fusion. The quantification of Cr(III) was accomplished by subtracting the Cr(VI) concentration from the total chromium concentration. The concentration of Cr(III) in the samples ranged from 10.9 to 88.0 mg kg-1, whereas only in few samples the Cr(VI) concentration was higher than the value established by the European Community to this type of sample [2 mg kg-1 Cr(VI)].

Mat��ria org��nica em quatro tipos de solos brasileiros: composi����o qu��mica e sor����o de atrazina

Soil organic matter is the main sorptive soil compartment for atrazine in soils, followed in a minor scale by the inorganic fraction. In this study, the soil organic matter quality and atrazine sorption were investigated in four different soil types. The pedogenic environment affected the humification and therefore the chemical composition of the organic matter. The organic matter contribution to atrazine sorption was larger (60-83%) than that of the inorganic fraction. The organic matter capacity in retaining the herbicide was favoured by a higher decomposition degree and a smaller carboxylic substitution of the aliphatic chains.

Alvejamento qu��mico de caulins Brasileiros: efeito do potencial eletroqu��mico da polpa e do ajuste do pH

Samples of Kaolin from different regions in Brazil were characterized by XRD, SEM and chemical analysis. A chemical bleaching study with pH adjustment was accomplished with the fractions below 37 &#956;m, after classification by screening. The main objective was to evaluate the conditions of chemical bleaching that most increase the brightness of these kaolin's samples. Increases between 2.63 and 2.98% in the brightness (ISO) were observed after the chemical bleaching. We could say that the reduction of Fe3+ to Fe2+ during the chemical bleaching promoted an increase in the brightness, based on the Pourbaix Diagrams.

Avalia����o geoqu��mica de ��leos brasileiros com ��nfase nos hidrocarbonetos arom��ticos

Aromatic compounds are still poorly evaluated in geochemical studies of Brazilian oil samples. For this reason, the objective of this work was to analyze and evaluate 26 oil samples from four Brazilian sedimentary basins. Aromatic hydrocarbon fractions have been analyzed by gas chromatography coupled to mass spectrometry. The results were also compared with previously evaluated saturated hydrocarbon data. Maturation parameters obtained using the 4- and 1-methyl-dibenzothiophenes and trimethyl-dibenzothiophenes led to the best results because a better grouping was observed. For this correlation, the samples were grouped by maturity degree enabling the routine use of these parameters to evaluate oil maturity levels.

Avalia����o de laborat��rios brasileiros na determina����o de alguns par��metros de qualidade de biocombust��veis

This work shows the results of a Proficiency Testing performed by a partnership between INMETRO and ANP. The performance of 49 Brazilian laboratories (using the z-score statistical test) in determining 10 quality parameters of ethanol fuel and biodiesel was evaluated. The certified reference values were provided by INMETRO, allowing a more rigorous assessment of the laboratories. For hydrous ethanol, the acidity parameter showed the lowest number of laboratories with satisfactory results (48%), while 85% of the laboratories presented satisfactory results for ethanol content. For biodiesel, the percentage of laboratories with satisfactory results ranged from 46% (kinematic viscosity) to 92% (acid number).

Teores de trigonelina, ��cido 5-cafeoilqu��nico, cafe��na e melanoidinas em caf��s sol��veis comerciais brasileiros

Commercial Brazilian regular and decaffeinated instant coffees (33 brands) were studied. The levels ranged from 0.47 to 2.15 g 100 g-1 for trigonelline, 0.38 to 2.66 g 100 g-1 for 5-caffeoylquinic acid (5-CQA), 0.24 to 4.08 g 100 g-1 for caffeine, and 0.253 to 0.476 (420 nm) for melanoidins. Variations in bioactive compound levels among batches were observed. There was no relationship between the drying process and the composition of the products. In general, Gourmet and decaffeinated coffees had higher trigonelline and 5-CQA but lower caffeine and melanoidin content than regular products.

Produ����o de hidrog��nio via fermenta����o anaer��bia - aspectos gerais e possibilidade de utiliza����o de res��duos agroindustriais brasileiros

Biological production of hydrogen through anaerobic fermentation has received increasing attention and offers a great potential as an alternative process for clean fuel production in the future. Considering biological systems for H2 production, anaerobic fermentation stands out, primarily due to its higher production of H2 compared with other biological processes. In addition the possibility of using different agro-industrial wastes as substrates opens up infinite possibilities. The development and implementation of sustainable processes for converting renewable materials into different value-added products is essential for the full exploitation of Brazilian agro-industrial wastes.

O que sabemos sobre os primeiros livros did��ticos brasileiros para o ensino de Qu��mica

This paper deals with the Brazilian textbooks of Chemistry from the XIX century to 1930. After presenting the science and its teaching contexts in Imperial Brazil and describing the first Chemistry textbook written by a Brazilian, the state of knowledge about these prime Brazilian books is presented. These works show the texts had strengths overlooked by current materials, a fact confirmed by analyzing textbooks from three authors from the period. The study concludes by compiling a list of 50 titles of early Chemistry books to help guide future research.

Separa����o e determina����o quantitativa dos alcanos lineares e dos c��clicos/ramificados em petr��leos brasileiros por aduto de ureia e cromatografia gasosa: um estudo de caso revisitado

A complete analysis of oils and their fractions allows correlations to be defined between their composition and derivatives or related geological materials. This work focused on optimization and implementation of a method for separation and quantification of n-alkanes in Brazilian oil samples by urea adduction and GC-FID techniques. Ten samples with different &#186;API were analyzed in triplicate to quantify individual n-alkanes and cyclic/branched alkane fraction. For individual quantification of n-alkanes, internal standardization with deuterated n-tetracosane was used. The use of urea adduction for the separation and quantification of n-alkanes was highly effective, with recovery values of above 80%.

Caracteriza����o molecular de dois isolados brasileiros de Lettuce mosaic virus apresentando propriedades biol��gicas distintas

Efetuou-se a clonagem e seq��enciamento do gene que codifica a prote��na capsidial de dois isolados do v��rus do mosaico da alface (Lettuce mosaic virus, LMV) provenientes do estado de S��o Paulo, previamente caracterizados como pertencentes aos pat��tipos II (AF198, incapaz de infetar cultivares com os genes de resist��ncia mo1�� ou mo1��) e IV (AF199, capaz de quebrar a resist��ncia propiciada pelos genes mo1�� e mo1��), com base na virul��ncia em cultivares diferenciadoras. An��lise comparativa das seq����ncias de nucleot��deos de isolados provenientes da Europa, Am��rica do Norte, Oriente M��dio e os dois isolados brasileiros n��o permitiu sua separa����o em estirpes, pois as porcentagens de homologia foram sempre superiores a 95%. Entretanto, an��lise filogen��tica dos isolados sugere uma origem comum entre o isolado AF-198 e os isolados LMV-R e LMV-0 (pat��tipo II, provenientes dos Estados Unidos e da Fran��a, respectivamente). O isolado AF199 apresentou uma alta homologia de seq����ncia com os isolados LMV-Aud e LMV-13, ambos provenientes da Fran��a. Esses isolados tamb��m s��o relacionados a isolados provenientes do Chile, embora uma origem comum n��o seja proposta. Eventos independentes de muta����o podem estar ocorrendo em diferentes partes do mundo, propiciando o surgimento de novas estirpes de LMV capazes de quebrar a resist��ncia conferida pelos genes mo1�� e mo1��.

Engraul��deos brasileiros, do g��nero Anchoa

Neste trabalho, o autor estuda os Engraul��deos do g��nero Anchoa ocorrentes no Brasil. Depois de se referir a quest��es de ordem nomenclatural, chama a aten����o para o fato de existirem diverg��ncias quanto �� caracteriza����o de esp��cies pertencentes a diversos g��neros, como, por exemplo, Anchoa e Anchoviella. Tendo examinado grande n��mero de exemplares encaminhados, para estudo, ao Instituto Paulista de Oceanografia, o autor, baseado em estudos feitos, em 1948, sob a dire����o do falecido Dr. SAMUEL F. HILDEBRAND, ictiologista do U. S. Fish &amp; Wildlife Service, de Washington, organizou uma chave para identifica����o das esp��cies de Anchoa ocorrentes em ��guas brasileiras. Ap��s ter discutido a significa����o do termo "manjuba", demonstra o autor a import��ncia econ��mica desses peixes, sobretudo no E. de S. Paulo onde grandes quantidades de Anchoa nasuta Hildebrand &amp; Carvalho, de Engtaulis anchoita Hubbs &amp; Marini e de Anchoa januaria (Steindachner) s��o utilizadas na ind��stria. Condena, ali��s, o autor a maneira pouco l��gica pela qual vem o produto sendo trabalhado, acrescentando que a mesma est�� longe de corresponder ao que dela se espera. Apresentando alguns dados biol��gicos sobre Anchoa januaria A. hepsetus hepsetus e A. tricolor, o autor d�� os caracteres de 10 esp��cimes frequentadores do litoral brasileiro, com os desenhos correspondentes a cada uma delas, figurando em duas estampas.

Engraul��deos brasileiros do g��nero Anchoviella

Nos anos de 1948-49, o autor teve ocasi��o de estudar os representantes da fam��lia Engraulidae que frequentam a costa brasileira, pesquisa essa supervisionada gentilmente pelo Dr. Samuel F. Hildebrand, icti��logo do U. S. Fish &amp; Wildlife Service, de Washington. Dessa investiga����o resultou a conveni��ncia de se identificar e redescrever as esp��cies que fazem parte das cole����es do Instituto Paulista de Oceanografia. O presente trabalho ��, pois, baseado na revis��o das manjubas americanas publicada pelo Dr. Hildebrand em 1943 e no trabalho em que figurou como co-autor: "Notes on some Brazilian anchovies (Family Engraulidae) with description of four new species" (1948). Gra��as �� gentileza do Dr. Hildebrand, foi examinada uma cole����o extensa do Museu Nacional dos Estados Unidos. De inestim��vel valor foi a manipula����o de exemplares constantes da cole����o do Dr. W. C. Schroeder, do Museu de Zoologia Comparada, especialmente rica em exemplares do Brasil. O autor muito deve ao Dr. Hildebrand pelo trabalho enorme desenvolvido nesse sentido. No texto, obedeceu-se a seq����ncia sempre uniforme quanto aos caract��res peculiares a cada esp��cie, de modo a facilitar o estudo, por parte de outras pessoas interessadas no grupo. A distribui����o geogr��fica dos esp��cimes aqui considerados figura no Mapa n.�� 1.

Produ����o e sensibilidade de isolados brasileiros de Xanthomonas axonopodis pv. citri �� bacteriocinas

Este trabalho teve por objetivo avaliar a produ����o e a sensibilidade de 48 isolados brasileiros de X. axonopodis pv. citri (Xac) �� bacteriocinas. Pelos resultados obtidos, nenhum isolado de Xac foi sens��vel ��s bacteriocinas produzidas pelos isolados bacterianos avaliados.