755 research outputs found

    Alimentação de bezerros com extrato hidrossolúvel de soja. II. Produção de anticorpos e distúrbios intestinais.

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    O Objetivo do trabalho foi avaliar a substituição total do sucedâneo lácteo à base de proteína de leite (SL) por extrato hidrossolúvel de soja (EHS) na alimentação de bezerros Holandeses machos, com idade média inicial de cinco dias. Os bezerros alimentados com EHS apresentaram diminuição visível das gorduras presentes no tecido subcutâneo, omento, epíplon e da gordura perirenal. No abomaso, a principal alteração verificada foi a falta de formação do coágulo do EHS ingerido

    Kinetics of Eucalypt Lignosulfonate Oxidation to Aromatic Aldehydes by Oxygen in Alkaline Medium

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    The oxidation kinetics of lignosulfonates (LS) from acidic magnesium-based sulfite pulping of Eucalyptus globulus wood with oxygen under alkaline conditions was studied. The analysis of oxidation products in the reaction system O(2)/NaOH revealed a predominance of aromatic aldehydes (vanillin and syringic aldehyde) though small amounts of vanillic and syringic acids and acetophenone/phenylacetaldehyde derivatives have also been detected. The rate constant of syringic aldehyde formation was roughly twice of that for vanillin. The effective activation energies for the oxidation of LS to aromatic aldehydes (ca. 60-70 kJ/mol) were rather different to those found for the formation of aromatic acids (ca. 110 kJ/mol) indicating different mechanisms involved in the rate-determining reaction step. The addition of catalyst (copper salt, 20% w/w) promoted the LS oxidation with increments of aromatic aldehyde yields by 25-50%. The maximum yields of syringic aldehyde and vanillin upon LS oxidation were 16.1 and 4.5%, respectively (150 degrees C, 20 min, P(O2) = 10 bar, 0.9 M NaOH solution). The highly negative effect of concomitant sugars in sulfite liquor to the yield of aromatic aldehydes was highlighted

    Can ocean warming alter sub-lethal effects of antiepileptic and antihistaminic pharmaceuticals in marine bivalves?

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    The negative effects induced in marine organisms by Climate Change related abiotic factors consequences, namely ocean warming, are well-known. However, few works studied the combined impacts of ocean warming and contaminants, as pharmaceutical drugs. Carbamazepine (CBZ) and cetirizine (CTZ) occur in the marine environment, showing negative effects in marine organisms. This study aimed to evaluate the impacts of ocean warming on the effects of CBZ and CTZ, when acting individually and combined (drug vs drug), in the edible clam Ruditapes philippinarum. For that, drugs concentration, bioconcentration factors and biochemical parameters, related with clam's metabolic capacity and oxidative stress, were evaluated after 28 days exposure to environmentally relevant scenarios of these stressors. The results showed limited impacts of the drugs (single and combined) at control and warming condition. Indeed, it appeared that warming improved the oxidative status of contaminated clams (higher reduced to oxidized glutathione ratio, lower lipid peroxidation and protein carbonylation levels), especially when both drugs were combined. This may result from clam's defence mechanisms activation and reduced metabolic capacity that, respectively, increased elimination and limited production of reactive oxygen species. At low stress levels, defence mechanisms were not activated which resulted into oxidative stress. The present findings highlighted that under higher stress levels clams may be able to activate defence strategies that were sufficient to avoid cellular damages and loss of redox homeostasis. Nevertheless, low concentrations were tested in the present study and the observed responses may greatly change under increased pollution levels or temperatures. Further research on this topic is needed since marine heat waves are increasing in frequency and intensity and pollution levels of some pharmaceuticals are also increasing in coastal systems.publishe

    Aqueous biphasic systems composed of ionic liquids: one-step extraction/concentration techniques for water pollution tracers

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    Emergent micropollutants have become a serious global problem with a large impact in the environment and human health, while their presence in aquatic systems has been registered as ranging from ng/L-1 to ug/L-1. Pharmaceuticals are ubiquitous micropollutants since their continuous consumption and consequent release via human excretions into aqueous systems are inevitable. Due to their usually low concentrations in aqueous samples, the development of a pre-concentration technique in order to continuously quantify and to monitor these components in aqueous streams is of major relevance. Aqueous biphasic systems (ABS) composed of ionic liquids (ILs) can be seen as more sustainable separation processes since they avoid the use of volatile and hazardous organic solvents (VOCs). As liquid-liquid systems, ABS can be used as extraction, purification and concentration platforms. Due to the outstanding tunable properties of ILs, IL-based ABS provide higher and more selective extraction efficiencies for a wide range of compounds when compared to traditional polymer-based ABS. IL-based ABS were already employed and adequately characterized for the extraction and concentration of endocrine disruptors, either from biological fluids or aqueous matrices. The aim of this work is to demonstrate the applicability of IL-based ABS to completely extract and concentrate, in one-step, two different and representative pharmaceutical pollution tracers, namely caffeine (CAF) and carbamazepine (CBZ). The low concentration of these persistent pollutants (usually found in ug/L-1 and ng/L-1 levels) does not allow a proper detection and quantification by conventional analytical equipment without a previous concentration step. However, pre-concentration methods commonly applied are costly, time-consuming, provide irregular recoveries and/or use VOCs. In this work, ABS composed of the IL tetrabutylammonium chloride ([N4444]Cl) and the salt K3C6H5O7 was investigated, demonstrating to be able to completely extract and concentrate CAF and CBZ in a single-step. Moreover, with this pre-treatment step it was demonstrated to be possible to overcome the detection limits of a high performance liquid chromatography coupled to an UV-Vis detector equipment. The results obtained demonstrate that IL-based ABS are versatile pre-concentration techniques, and can be used for the extraction and concentration of a large plethora of other micropollutants from environmental aqueous matrices.publishe

    Producing magnetic nanocomposites from paper sludge for the adsorptive removal of pharmaceuticals from water: a fractional factorial design

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    In view of a simple after-use separation, the potentiality of producing magnetic activated carbon (MAC) by intercalation of ferromagnetic metal oxide nanoparticles in the framework of a powder activated carbon (PAC) produced from primary paper sludge was explored in this work. The synthesis conditions to produce cost effective and efficient MACs for the adsorptive removal of pharmaceuticals (amoxicillin, carbamazepine, and diclofenac) from aqueous media were evaluated. For this purpose, a fractional factorial design (FFD) was applied to assess the effect of the most significant variables (Fe3+ to Fe2+ salts ratio, PAC to iron salts ratio, temperature, and pH), on the following responses concerning the resulting MACs: Specific surface area (SBET), saturation magnetization (Ms), and adsorption percentage of amoxicillin, carbamazepine, and diclofenac. The statistical analysis revealed that the PAC to iron salts mass ratio was the main factor affecting the considered responses. A quadratic linear regression model A = f(SBET, Ms) was adjusted to the FFD data, allowing to differentiate four of the eighteen MACs produced. These MACs were distinguished by being easily recovered from aqueous phase using a permanent magnet (Ms of 22-27 emu g-1), and their high SBET (741-795 m2 g-1) were responsible for individual adsorption percentages ranging between 61% and 84% using small MAC doses (35 mg L-1).publishe
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