Caracterização físico-química de polpas de frutos da Amazônia e sua correlação com a atividade anti-radical livre

Características físico-químicas (cor, pH, acidez total titulável, sólidos solúveis totais, conteúdo de lipídios e umidade) e níveis de compostos bioativos (ácido ascórbico, fenólicos totais) foram determinados em quinze amostras de polpas de frutos procedentes da região Amazônica (abiu, acerola, açaí, araçá-boi, bacaba, bacuri, buriti, cajá, cajarana, caju, cupuaçu, graviola, murici, noni e tamarindo). A atividade de radicais livres foi avaliada pelo método de ABTS. Algumas polpas apresentaram alta potencialidade antioxidante, associada com a atividade antirradicais livres obtida e os conteúdos dos componentes bioativos como compostos fenólicos e ácido ascórbico, destacando-se acerola e acaí. O conteúdo total de compostos fenólicos foi correlacionado à capacidade antioxidante das polpas.

Transport of North African dust from the Bod,l, depression to the Amazon Basin: a case study

Through long-range transport of dust, the North-African desert supplies essential minerals to the Amazon rain forest. Since North African dust reaches South America mostly during the Northern Hemisphere winter, the dust sources active during winter are the main contributors to the forest. Given that the Bod,l, depression area in southwestern Chad is the main winter dust source, a close link is expected between the Bod,l, emission patterns and volumes and the mineral supply flux to the Amazon. Until now, the particular link between the Bod,l, and the Amazon forest was based on sparse satellite measurements and modeling studies. In this study, we combine a detailed analysis of space-borne and ground data with reanalysis model data and surface measurements taken in the central Amazon during the Amazonian Aerosol Characterization Experiment (AMAZE-08) in order to explore the validity and the nature of the proposed link between the Bod,l, depression and the Amazon forest. This case study follows the dust events of 11-16 and 18-27 February 2008, from the emission in the Bod,l, over West Africa (most likely with contribution from other dust sources in the region) the crossing of the Atlantic Ocean, to the observed effects above the Amazon canopy about 10 days after the emission. The dust was lifted by surface winds stronger than 14 m s(-1), usually starting early in the morning. The lofted dust, mixed with biomass burning aerosols over Nigeria, was transported over the Atlantic Ocean, and arrived over the South American continent. The top of the aerosol layer reached above 3 km, and the bottom merged with the boundary layer. The arrival of the dusty air parcel over the Amazon forest increased the average concentration of aerosol crustal elements by an order of magnitude.

Atlantic forest: A natural reservoir of chemical elements

The accumulation of chemical elements in biological compartments is one of the strategies of tropical species to adapt to a low-nutrient soil. This study focuses on the Atlantic Forest because of its eco-environmental importance as a natural reservoir of chemical elements. About 20 elements were determined by INAA in leaf, soil, litter and epiphyte compartments. There was no seasonality for chemical element concentrations in leaves, which probably indicated the maintainance of chemical elements in this compartment. Considering the estimated quantities, past deforestation events could have released large amounts of chemical elements to the environment.

Screening of lipases for the synthesis of xylitol monoesters by chemoenzymatic esterification and the potential of microwave and ultrasound irradiations to enhance the reaction rate

Lipases from different sources, Pseudomonas fluorescens (AK lipase), Burkholderia cepacia (PS lipase), Penicillium camembertii (lipase G) and Porcine pancreas lipase (PPL), previously immobilized on epoxy SiO(2)-PVA, were screened for the synthesis of xylitol monoesters by esterification of the protected xylitol using oleic acid as acyl donor group. Among all immobilized derivatives, the highest esterification yield was achieved by P. camembertii lipase, showing to be attractive alternative to bulk chemical routes to satisfy increasing commercial demands. Further experiments were performed to determine the influence of fatty acids chain size on the reaction yield and the feasibility of using non-conventional heating systems (microwave and ultrasound irradiations) to enhance the reaction rate. (C) 2010 Elsevier B.V. All rights reserved.

Nestmate recognition in the stingless bee Frieseomelitta varia (Hymenoptera, Apidae, Meliponini): sources of chemical signals

Social insects use cuticular lipids for nestmate recognition. These lipids are chiefly hydrocarbons that can be endogenously produced or acquired from the environment. Although these compounds are already described as coming from different sources for different groups of social insects, nothing is known about the source of cuticular hydrocarbons in stingless bees. We used behavioural recognition tests and cuticle chemical investigation to elucidate the role of endogenous and environmentally based cues for nestmate recognition in the stingless bee Frieseomelitta varia. We found that although newly emerged workers present specific cuticle patterns according to their nest origin, these compounds are not used for nestmate recognition, since newly emerged workers are broadly accepted in different colonies. The cerumen used in nest construction played an important role in recognition behaviour. Twenty minutes of contact with foreign cerumen was sufficient to increase the rejection rates of nestmates and separate the groups of workers according to their chemical profile. On the other hand, tests of feeding on a common diet showed no effect on chemical cuticle pattern or recognition behaviour. (C) 2010 The Association for the Study of Animal Behaviour. Published by Elsevier Ltd. All rights reserved.

Numerical simulation of double-diffusion driven convective flow and rock alteration in three-dimensional fluid-saturated geological fault zones

Numerical methods are used to simulate the double-diffusion driven convective pore-fluid flow and rock alteration in three-dimensional fluid-saturated geological fault zones. The double diffusion is caused by a combination of both the positive upward temperature gradient and the positive downward salinity concentration gradient within a three-dimensional fluid-saturated geological fault zone, which is assumed to be more permeable than its surrounding rocks. In order to ensure the physical meaningfulness of the obtained numerical solutions, the numerical method used in this study is validated by a benchmark problem, for which the analytical solution to the critical Rayleigh number of the system is available. The theoretical value of the critical Rayleigh number of a three-dimensional fluid-saturated geological fault zone system can be used to judge whether or not the double-diffusion driven convective pore-fluid flow can take place within the system. After the possibility of triggering the double-diffusion driven convective pore-fluid flow is theoretically validated for the numerical model of a three-dimensional fluid-saturated geological fault zone system, the corresponding numerical solutions for the convective flow and temperature are directly coupled with a geochemical system. Through the numerical simulation of the coupled system between the convective fluid flow, heat transfer, mass transport and chemical reactions, we have investigated the effect of the double-diffusion driven convective pore-fluid flow on the rock alteration, which is the direct consequence of mineral redistribution due to its dissolution, transportation and precipitation, within the three-dimensional fluid-saturated geological fault zone system. (c) 2005 Elsevier B.V. All rights reserved.

Genes Differentially Expressed in Prolactinomas Responsive and Resistant to Dopamine Agonists

Background/Aims: Prolactin (PRL) secretion and its gene expression are inhibited by dopamine. Prolactinomas are the most common secreting pituitary adenomas, and dopamine agonists (DA) are the first choice for their treatment. However, a subset of patients is resistant to DA. As the mechanisms involved in DA resistance are not fully understood, the aim of this study was to obtain new insights regarding the molecular differences between the prolactinomas that are responsive to DA and those that are resistant. Methods: Tumor tissue samples were collected from 17 patients who harbored prolactinomas, which were classified as responsive or resistant according to their clinical and laboratorial reaction to DA. The expression of 6 genes was evaluated by real-time polymerase chain reaction: dopamine receptor type 2 (DRD 2), nerve growth factor-beta (NGFB) and its receptor (NGFR), estrogen receptor-alpha (ERA), estrogen receptor-beta (ERB) and the pituitary tumor transforming gene (PTTG). Results: Median DRD 2 and NGFR expression in responsive patients was significantly higher than in resistant ones (p = 0.029 and p = 0.020, respectively). Moreover, the expressions of DRD 2 and NGFR were positively correlated with PRL decrease during treatment (r = 0.66, p = 0.005 and r = 0.57, p = 0.044, respectively). Furthermore, ERB expression was positively correlated to PTTG expression (r = 0.68, p = 0.032) and negatively correlated to NGFB expression (r = -0.75, p = 0.02). Conclusions: DRD2 and NGFR expressions are related to the responsiveness of prolactinoma to DA. However, PTTG, ERB and ERA expressions are not. Also ERB, ERA and PTTG expressions did not present a clear correlation to tumor aggressiveness. Furthermore, the response of prolactinomas to DA should be viewed as a spectrum ranging from the most responsive to the most resistant ones. Copyright (c) 2008 S. Karger AG, Basel

Elephants and polity in ancient India as exemplified by Kautilya's Arthasastra (Science of Polity)

After providing some background on the domestication and use of elephants in ancient India, this article concentrates on the role of the elephant in Indian statescraft as outlined in Kautilya’s Arthasastra, reputed to have been written in the fourth century BC (over 2300 years ago). The body of this essay is presented as follows: first background on the nature of Kautilya’s Arthasastra is provided and then his advice is outlined and discussed about the care of elephants. This care involves the duty of the King, the duties of the superintendent of elephants and the law relating to the treatment of elephants. Subsequently, Kautilya’s views about the use of elephants in war are considered. The essay concludes with an overall assessment of the role of the elephant in the polity of ancient India as portrayed by Kautilya. It is argued that the high use value of elephants to ancient Indian rulers, especially in war, had a significant positive impact on the conservation of Asian wild elephants, and incidentally other wildlife in India as well. Today, the conservation of the Asian elephant depends mostly on its use for tourism and its non-use economic values which reflect human empathy with it and which are reinforced in India by social and cultural values.

Relationship between flocculation of activated sludge and composition of extracellular polymeric substances

Activated sludge floes are a flocculated mass of microorganisms, extracellular polymeric substances (EPS) and adsorbed organic and inorganic material. The structure of the floes is very heterogeneous and floes with very different properties and morphologies may occur, depending on the conditions in the activated sludge treatment plant and wastewater composition. Present thinking suggests that cations, such as calcium, create cationic bridges with EPS excreted by the bacteria and thereby hold the various floe constituents together. However, due to the complex and heterogeneous nature of activated sludge, the mechanisms have neither been thoroughly investigated nor successfully quantified. A better understanding and description of the biological flocculation process is necessary in order to establish more efficient operational strategies. The main aim of this study was to get a comprehensive and unique insight into the floe properties of activated sludge and to assess the relative impact of chemical and physical parameters. A variety of sludges from full scale treatment plants with different settling properties were characterised. The interrelationships between floe parameters such as composition of EPS, surface properties and floe structure, and their effect on the flocculation and separation properties were assessed. The results indicate that the EPS, both in terms of quantity and quality, are very important for the floe properties of the activated sludge. However, presence of filaments may alter the physical properties of the floes considerably. The EPS showed positive correlations to sludge volume index (SVI) if only sludges with low or moderate numbers of filaments were included. The surface properties were more affected by the composition of the EPS than by the number of filaments. The EPS showed positive correlation to negative surface charge and a negative correlation to relative hydrophobicity and flocculation ability. The negative correlation between flocculation ability and amount of EPS was surprising. The shear sensitivity, measured as degree of erosion of floes when subjected to shear, was more affected by floe size and number of filaments than amount of EPS.

Analysis of constructed wetland performance for irrigation reuse

Most of the wastewater treatment systems in small rural communities of the Cova da Beira region (Portugal) consist of constructed wetlands (CW) with horizontal subsurface flow (HSSF). It is believed that those systems allow the compliance of discharge standards as well as the production of final effluents with suitability for reuse. Results obtained in a nine-month campaign in an HSSF bed pointed out that COD and TSS removal were lower than expected. A discrete sampling also showed that removal of TC, FC and HE was not enough to fulfill international irrigation goals. However, the bed had a very good response to variation of incoming nitrogen loads presenting high removal of nitrogen forms. A good correlation between mass load and mass removal rate was observed for BOD5, COD, TN, NH4-N, TP and TSS, which shows a satisfactory response of the bed to the variable incoming loads. The entrance of excessive loads of organic matter and solids contributed for the decrease of the effective volume for pollutant uptake and therefore, may have negatively influenced the treatment capability. Primary treatment should be improved in order to decrease the variation of incoming organic and solid loads and to improve the removal of COD, solids and pathogenic. The final effluent presented good physical-chemical quality to be reused for irrigation, which is the most likely application in the area.

Estudo da tratabilidade laboratorial e optimização experimental do tratamento de águas residuais de indústrias lácteas

O presente trabalho experimental teve como objectivos estudar a tratabilidade dum efluente lácteo utilizando a técnica de coagulação/floculação e avaliar a possibilidade de utilização do carvão activado granulado (CAG) Aquasorb 2000 como adsorvente para a remoção de compostos orgânicos presentes nos efluentes lácteos pré–tratados por coagulação/floculação, funcionando como um tratamento de polimento. No estudo da tratabilidade do efluente por coagulação/floculação investigou-se a influência de determinadas variáveis como o tipo e dose de coagulante e pH, a fim de encontrar as melhores condições operatórias. A utilização da referida técnica visou a redução do valor de concentração de alguns parâmetros: carência química de oxigénio (CQO); fósforo total e turvação, tendo sido utilizados efluentes desta indústria recolhidos em diferentes datas e após tratamento biológico, designados por A, B, C e D apresentando características diferentes. Sendo que o efluente A apresentava valores de CQO, fósforo total e turvação de 500 mg O2/L;32 mg P/L e 40 NTU respectivamente, o efluente B 1400 mg O2/L; 120 mg P/L e 80 NTU respectivamente, o efluente C 12300 mg O2/L; 87 mg P/L e 350 NTU respectivamente e o efluente D 340 mg O2/L; 33 mg P/L e 42 NTU respectivamente. Os coagulantes estudados foram hidróxido de cálcio (HC), sulfato de alumínio (SA) e tricloreto de ferro (TF). Verificou-se que o coagulante com maior eficácia nos efluentes estudados foi o TF. As maiores remoções de CQO, fósforo total e turvação, 89%, 99,9% e 99%, respectivamente, foram obtidas para o efluente C, com uma dosagem de TF de 4 g/L e com um pH entre 6 e 7. Entre os efluentes estudados este era o que apresentava valores iniciais mais elevados para qualquer um destes parâmetros. As melhores percentagens de remoção obtidas com o HC, para a CQO, fósforo total e turvação foram de 59%, 99% e 91%, respectivamente, com uma dosagem de HC de 1 g/L e com um pH entre 10 e 11,5 foram conseguidas no tratamento do efluente D, com o qual se alcançaram também as melhores remoções de CQO, fósforo total e turvação de 65%, 99% e 87%, respectivamente, quando se utilizou o coagulante SA, com uma dosagem de 2 g/L e com um pH entre 7 e 7,5. Relativamente ao volume de lamas produzido neste processo pela utilização dos diferentes coagulantes no tratamento dos efluentes referidos concluiu-se que o coagulante que gera menor volume de lamas é o HC, sendo o SA aquele que origina um maior volume. Submeteu-se posteriormente o efluente D, pré-tratado por coagulação/floculação, a um processo de adsorção em batch utilizando o CAG Aquasorb 2000, onde se conseguiu uma remoção de CQO de 48%, alcançando para este parâmetro o valor de 63 mg O2/L, nas condições operatórias que correspondem a uma massa de CAG de 12,5 g/L e um tempo de contacto de 3 horas. Quanto aos custos associados com os coagulantes, o que menores custos apresenta é o HC (150 €/ton), seguido pelo TF (250 €/ton) e por ultimo o SA (340 €/ton). Sendo que o efluente quando tratado com TF e SA é necessário uma correcção do pH do meio para que estes coagulantes actuem eficazmente, em que essa correcção de pH é realizada com hidróxido de sódio (540 €/ton). Realizaram-se ainda estudos de equilíbrio de adsorção com o carvão activado referido e o azul-de-metileno usando diferentes concentrações deste (50 mg/L; 100 mg/L e 200 mg/L) e diferentes massas de CAG (0,1g; 0,2g; 0,3g; 0,4g e 0,5g). A temperatura a que se realizaram estes ensaios foi de 28,7ºC e o volume de azul-de-metileno foi de 200 mL. Verificou-se que os melhores resultados obtidos foram para uma concentração de adsorvato de 100 mg/L. Ajustaram-se os modelos de Langmuir e Freundlich às isotérmicas obtidas tendo correlações mais elevadas para a concentração de 100 mg/L de corante (azul de metileno), sendo o modelo de Freundlich aquele que melhor se ajustou apresentando uma correlação quadrática de 0,9744 e os seguintes parâmetros Kf = 6,59 e n = 5,33, enquanto que o de Langmuir apresentou uma correlação quadrática de 0,9583 e os seguintes parâmetros qmáx = 83,3 mg/g de adsorvente e K = 20 L/mg de adsorvato.. Verificou-se que a capacidade de adsorção promovida pelo CAG, em relação ao azul-demetileno, obtida experimentalmente, 83,3 mg/g, é muito inferior à capacidade de adsorção teoricamente prevista pela ficha técnica deste carvão, 280 mg/g a uma temperatura de 25ºC, o que pode indiciar que o carvão utilizado não estaria nas melhores condições.

Desenvolvimento de métodos rápidos para deteção de drogas no meio aquático

A vasta aplicação de antibióticos em sistemas de aquacultura tem conduzido ao aparecimento de espécies microbianas resistentes, devendo ser evitada ou, se possível, minimizada. A minimização implica um controlo muito rigoroso das doses aplicadas, algo que só pode ser realizado se todo o processo analítico for simples, barato e puder ser implementado no local. O presente trabalho descreve para este efeito um sistema sensor constituído por papel quimicamente modificado, cujo procedimento analítico foi semelhante à monitorização de pH através das conhecidas tiras indicadoras de pH universal. O papel foi modificado com base em reacções de monocamadas e assumiu uma coloração típica após contacto com o antibiótico. A intensidade da coloração estava também relacionada com a concentração desse antibiótico. Como prova deste conceito, o sensor proposto foi desenhado tendo em vista a monitorização de oxitetraciclina, um dos antibióticos utilizados neste contexto com elevada frequência. A modificação do papel foi baseada na alteração química das unidades de glucose na matriz sólida por reacção covalente com reagentes apropriados. Foram utilizadas duas estratégias diferentes para este efeito: uma foi baseada em reacções de tipo sol-gel e a outra em reacção de adição nucleófila. Posteriormente, o papel foi modificado com espécies metálicas capazes de mudar de cor na presença da oxitetraciclina. Estas modificações químicas foram avaliadas e optimizadas relativamente a vários parâmetros, no sentido de promover uma variação de cor intensa face à concentração de antibiótico. Procedeu-se ainda ao controlo desta modificação por técnicas de espectroscopia de infravermelho. A variação de cor foi avaliada por comparação visual, mas registada por imagem digital. Os materiais sensores preparados foram ainda caracterizados do ponto de vista do seu desempenho analítico. Incluíram-se aqui a identificação de uma relação linear entre coordenadas de cor e concentração, a atribuição de uma gama de concentrações capaz de fornecer uma resposta previsível e resposta cruzada face a outros antibióticos. Procedeu-se ainda à aplicação dos sensores numa amostra de água ambiental dopada com antibiótico. De uma forma geral, foi possível estabelecer um processo simples de modificação de papel capaz de aferir a presença e a quantidade de tetraciclinas, mais concretamente a oxitetraciclina. O processo aqui estabelecido é promissor, antevendo a concretização de uma metodologia simples, barata e local para a monitorização de anitbióticos em águas.

Portal cd4+ and cd8+ t lymphocyte correlate to intensity of interface hepatitis in chronic hepatitis C

BACKGROUND: The pathogenesis of chronic hepatitis C is still a matter of debate. CD4+ and CD8+ T lymphocytes (TL) are typically observed within the portal and periportal spaces of affected livers, but their functional role in hepatitis C progression has not been fully elucidated. METHODS: CD4+ and CD8+ TL were quantified by immunohistochemistry in portal and periportal spaces of 39 liver biopsies from patients with chronic hepatitis C. They were associated to demographic data, histological parameters, laboratory findings of patients and hepatitis C genotypes. RESULTS: There was high numbers of CD4+ and CD8+ TL from which the density of CD4+ T was higher than CD8+ TL in portal and periportal spaces. CD4+ and CD8+ TL were directly correlated to intensity of interface hepatitis. CD8+ TL correlated to serum enzyme levels. CONCLUSION: The high numbers of CD4+ and CD8+ TL in portal and periportal spaces and their correlation to interface hepatitis suggest that hepatitis C evolution depends on the action of intrahepatic T lymphocytes, lending support to the notion of an immune-mediated mechanism in the pathogenesis of chronic hepatitis C.

Metodologias para a qualificação de águas minerais naturais e águas de nascente

Dissertação de mestrado em Ordenamento e Valorização de Recursos Geológicos

A contribution to the study of simulium and Culicoides of Rio de Janeiro: monthly incidence and biting activity

During March 1984 to February 1985, we captured simuliids and biting midges in the National Park of Tijuca, Rio de Janeiro. A study on monthly incidence and biting activity and their correlation to air temperature, relative humidity, and rainfall was made.