Podzolization as a deferralitization process: dynamics and chemistry of ground and surface waters in an Acrisol-Podzol sequence of the upper Amazon Basin

Hydrochemical processes involved in the development of hydromorphic Podzols are a major concern for the upper Amazon Basin because of the extent of the areas affected by such processes and the large amounts of organic carbon and associated metals exported to the rivers. The dynamics and chemical composition of ground and surface waters were studied along an Acrisol-Podzol sequence lying in an open depression of a plateau. Water levels were monitored along the sequence over a period of 2 years by means of piezometers. Water was sampled in zero-tension lysimeters for groundwater and for surface water in the drainage network of the depression. The pH and concentrations of organic carbon and major elements (Si, Fe and Al) were determined. The contrasted changes reported for concentrations of Si, organic carbon and metals (Fe, Al) mainly reflect the dynamics of the groundwater and the weathering conditions that prevail in the soils. Iron is released by the reductive dissolution of Fe oxides, mostly in the Bg horizons of the upslope Acrisols. It moves laterally under the control of hydraulic gradients and migrates through the iron-depleted Podzols where it is exported to the river network. Aluminium is released from the dissolution of Al-bearing minerals (gibbsite and kaolinite) at the margin of the podzolic area but is immobilized as organo-Al complexes in spodic horizons. In downslope positions, the quick recharge of the groundwater and large release of organic compounds lead to acidification and a loss of metals (mainly Al), previously stored in the Podzols.

X ray densitometry applied to technological evaluation of MDF panels of eucalyptus

MDF panels from eucalyptus wood fibers were manufactured in laboratory and industrial production and had their apparent density profile determined by X-ray densitometry. The MDF panels apparent density parameters (maximum density of the superior and inferior faces; medium and minimum density) were determined and compared. The results indicated that the density values of the MDF panels made in the laboratory and in industrial line did not show significant statistical differences, indicating the similarities in the pressing phase of the fibers of both kinds. However, for MDF panels of laboratory and production line, the values of maximum, mean and minimum densities showed statistically significant correlations. The determination of the density profile for MDF panels by X-ray densitometry is important for the evaluation of pressing phase and other variables of the industrial process of production, as well for the determination of the technological properties.

Cyanobacteria and Cyanotoxin in the Billings Reservoir (Sao Paulo, SP, Brazil)

The Billings Complex and the Guarapiranga System are important strategic reservoirs for the city of Sao Paulo and surrounding areas because the water is used among other things, for the public water supply. They produce 19,000 liters of water per second and Supply water to 5.4 million people. Crude water is transferred from the Taquacetuba branch of the Billings Complex to the Guarapiranga Reservoir to regulate the water level of the reservoir. The objective of this study was to evaluate the water quality in the Taquacetuba branch, focusing on cyanobacteria and cyanotoxins. Surface water samples were collected in February (summer) and July (winter) of 2007. Analyses were conducted of physical, chemical, and biological variables of he water, cyanobacteria richness and density, and the presence of cyanotoxins. The water was classified as eutrophic-hypereutrophic. Cyanobacteria blooms were observed in both collection periods. The cyanobacteria bloom was most significant in July, reflecting lower water transparency and higher levels of total solids, suspended organic matter, chlorophyll-a, and cyanobacteria density in the surface water. Low richness and elevated dominance of the cyanobacteria were found in both periods. Cylindrospermopsis raciborskii was dominant in February, with 352 661.0 cel mL(-1), and Microcystis panniformis was dominant in July, with 1 866 725.0 cel mL(-1). Three variants of microcystin were found in February (MC-RR, MC-LR, MC-YR), as well as saxitoxin. The same variants of microcystin were found in July, but no saxitoxin was detected. Anatoxin-a and cylindropermopsin were not detected in either period. These findings are of great concern because the water in the Taquacetuba branch, which is transferred into the Guarapiranga Reservoir, is not treated nor managed. It is recommended that monitoring be intensified and more effective measures be taken by the responsible agencies to prevent the process of eutrophication and the consequent development of the cyanobacteria and their toxins.

Development and Characterization of L-Alanyl-L-Glutamine Containing Pellets employing Extrusion-Spheronization Method and Drying Process in Fluidized Bad Equipment.

Development and Characterization of L-Alanyl-L-Glutamine Containing Pellets employing Extrusion-Spheronization Method and Drying Process in Fluidized Bad Equipment"". In this work, five formulations of L-alanyl-L-glutamine (glutamine dipeptide) containing pellets with different drug concentration were developed and evaluated: F1 (9.07%); F2 (17.70%); F3 (27.98%); F4 (37.74%) e F5 (47.53%). Pellets were prepared by extrusion-spheronization method and, further, dried in fluidized bad equipment. The following assays were carried out with the batches obtained: granulometry, friability, true density and morphologic analysis. Between the five formulations evaluated, pellets obtained from F3 present best yield (75.80%), most uniform particle size distribution (89.67% of pellets with size in the range of 0.80 to 1.18), most high true density (2.1634 g/ml) and best aspect (1.0795 +/- 0.0410). Due to these features, pellets obtained from F3 were considered adequate to further polymeric coating process in order to produce a multiparticulate system to prolong L-alanyl-L-glutamine release.

Dissolution parameters for sodium diclofenac-containing hypromellose matrix tablet

Sodium diclofenac (SD) release from dosage forms has been studied under different conditions. However, no dissolution method that is discriminatory enough to reflect slight changes in formulation or manufacturing process, and which could be effectively correlated with the biological properties of the dosage form, has been reported. This study sought to develop three different formulae of SD-containing matrix tablets and to determine the effect of agitation speed in its dissolution profiles. F1, F2 and F3 formulations were developed using hypromellose (10, 20 and 30%, respectively for F1, F2 and F3) and other conventional excipients. Dissolution tests were carried out in phosphate buffer pH 6.8 at 37 degrees C using apparatus 11 at 50, 75 or 100 rpm. Dissolution efficiency (DE), T(50) and T(90) were determined and plotted as functions of the variables agitation speed and hypromellose concentration. Regarding DE, F2 showed more sensitivity to variations in agitation speed than F1 and F3. Increasing hypromellose concentration reduced DE values, independent of agitation speed. Analysis of T(50) and T(90) suggests that F1 is less sensitive to variations in agitation speed than F2 and F3. Most discriminatory dissolution conditions were observed at 50 rpm. Results suggest that the comparison of dissolution performance of SD matrix tablets should take into account polymer concentration and agitation conditions. (C) 2009 Published by Elsevier B.V.

Process Capability Indexes Determination on Tabletting Performance during the Process Validation for Metamizol Tablets

The aim of the present study was to provide a numerical measure, through the process capability indexes (PCIs), C(p) and C(pk), on whether or not the manufacturing process can be considered capable of producing metamizol (500 mg) tablets. They were also used as statistical tool in order to prove the consistency of the tabletting process, making sure that the tablet weight and the content uniformity of metamizol are able to comply with the preset requirements. Besides that, the ANOVA, the t-test and the test for equal variances were applied to this study, allowing additional knowledge of the tabletting phase. Therefore, the proposed statistical approach intended to assure more safety, precision and accuracy on the process validation analysis.

Optimization of preservative system in ophthalmic suspension with dexamethasone and polymyxin B

A simplex-lattice statistical project was employed to study an optimization method for a preservative system in an ophthalmic suspension of dexametasone and polymyxin B. The assay matrix generated 17 formulas which were differentiated by the preservatives and EDTA (disodium ethylene diamine-tetraacetate), being the independent variable: X-1 = chlorhexidine digluconate (0.010 % w/v); X-2 = phenylethanol (0.500 % w/v); X-3 = EDTA (0.100 % w/v). The dependent variable was the Dvalue obtained from the microbial challenge of the formulas and calculated when the microbial killing process was modeled by an exponential function. The analysis of the dependent variable, performed using the software Design Expert/W, originated cubic equations with terms derived from stepwise adjustment method for the challenging microorganisms: Pseudomonas aeruginosa, Burkholderia cepacia, Staphylococcus aureus, Candida albicans and Aspergillus niger. Besides the mathematical expressions, the response surfaces and the contour graphics were obtained for each assay. The contour graphs obtained were overlaid in order to permit the identification of a region containing the most adequate formulas (graphic strategy), having as representatives: X-1 = 0.10 ( 0.001 % w/v); X-2 = 0.80 (0.400 % w/v); X-3 = 0.10 (0.010 % w/v). Additionally, in order to minimize responses (Dvalue), a numerical strategy corresponding to the use of the desirability function was used, which resulted in the following independent variables combinations: X-1 = 0.25 (0.0025 % w/v); X-2 = 0.75 (0.375 % w/v); X-3 = 0. These formulas, derived from the two strategies (graphic and numerical), were submitted to microbial challenge, and the experimental Dvalue obtained was compared to the theoretical Dvalue calculated from the cubic equation. Both Dvalues were similar to all the assays except that related to Staphylococcus aureus. This microorganism, as well as Pseudomonas aeruginosa, presented intense susceptibility to the formulas independently from the preservative and EDTA concentrations. Both formulas derived from graphic and numerical strategies attained the recommended criteria adopted by the official method. It was concluded that the model proposed allowed the optimization of the formulas in their preservation aspect.

Effects of light intensity and dilution rate on the semicontinuous cultivation of Arthrospira (Spirulina) platensis. A kinetic Monod-type approach

Semicontinuous cultures were carried out at different dilution rates (D) and light intensities (I) to determine the maximum productivity of Arthrospira platensis cultivated in helicoidal photobioreactor up to the achievement of pseudo-steady-state conditions. At I = 108 mu mol photons m(-2) s(-1), the semicontinuous regime ensured the highest values of maximum cell concentration (X(m) = 5772 +/- 113 mg L(-1)) and productivity (P(XS) = 1319 +/- 25 mg L(-1) d(-1)) at the lowest (D = 0.1 day(-1)) and the highest (D = 0.3 day(-1)) dilution rates, respectively. A kinetic model derived from that of Monod was proposed to determine the relationship between the product of light intensity to dilution rate (ID) and the cell productivity, which were shown to exert a combined influence on this parameter. This result put into evidence that pseudosteady-state conditions could be modified according to circumstances, conveniently varying one or other of the two independent variables. (C) 2010 Elsevier Ltd. All rights reserved.

Extractive Fermentation of Clavulanic Acid by Streptomyces DAUFPE 3060 Using Aqueous Two-Phase System

The influence of four variables, specifically PEG molar mass (400, 1,000, and 8,000 g/mol), concentrations of PEG and phosphate salts (15, 20, and 25% for both), and agitation intensity (110, 150, and 200 rpm), on clavulanic acid (CA) extraction by extractive fermentation with PEG/phosphate salts aqueous two-phase system was investigated in shaken flasks using a 2(4-1)-fractional factorial design. After selection of the two most significant variables (agitation intensity and PEG molar mass), an optimization study conducted according to a 2(2)-central composite design revealed that 25% PEG 8,000 g/mol and phosphate salts at 240 rpm (run 6) were the best conditions for the extractive fermentation, leading to the best results in terms of partition coefficient (k = 8.2), yield of CA in the PEG-rich phase (eta(T) = 93%) and productivity (P = 5.3 mg/Lh). As a first attempt to make a scale-up of these results, the effectiveness of the extractive fermentation was then checked in a bench-scale bioreactor under conditions as close as possible to the optimum ones determined in flasks. The highest CA concentration obtained in the PEG-rich phase (691 mg/L) was 30% higher than in flasks, thus demonstrating the potential of such a new process, integrating the production and extraction steps, as a promising, low-cost tool to obtain high yields of this and similar products. (C) 2010 American Institute of Chemical Engineers Biotechnol. Prog., 27: 95-103, 2011

Transient process in ice creams evaluated by laser speckles

When a coherent light beam is scattered from a colloidal medium, in the observation plane, appears a random grainy image known as speckle pattern. The time evolution of this interference image carries information about the ensemble-averaged dynamics of the scatterer particles. The aim of this work was to evaluate the use of dynamic speckles as an alternative tool to monitoring frozen foams formulated with glucose and fructose syrups. Ice creams, after preparation and packing, were stored at 18 degrees C. Changes in properties of products were analyzed by speckle phenomena at three room temperatures (20 degrees C, 25 degrees C and 30 degrees C), minute by minute, during 50 min. Two moments were identified in which samples activity achieved significant levels. These instants were associated, respectively, to ice crystals melting and to air bubbles dissipation into the food matrix causing motion of diverse structures. As expected, ice crystals melting was first in formulations containing fructose syrup, but for same samples, air losses were delayed. Speckle methodology was satisfactory to observe temporal evolution of transient process, opening goods prospects to application, still incoming, in foodstuffs researches. (C) 2010 Elsevier Ltd. All rights reserved.

Fed-batch cultivation of Arthrospira (Spirulina) platensis: Potassium nitrate and ammonium chloride as simultaneous nitrogen sources

Arthrospira platensis was cultivated in minitanks at 13 klux, using a mixture of KNO(3) and NH(4)Cl as nitrogen source. Fed-batch daily supply of NH(4)Cl at exponentially-increasing feeding rate allowed preventing ammonia toxicity and nitrogen deficiency, providing high maximum cell concentration (X(m)) and high-quality biomass (21.85 mg chlorophyll g cells(-1); 20.5% lipids; 49.8% proteins). A central composite design combined to response surface methodology was utilized to determine the relationships between responses (X(m), cell productivity and nitrogen-to-cell conversion factor) and independent variables (KNO(3) and NH(4)Cl concentrations). Under optimum conditions (15.5 mM KNO3; 14.1 mM NH(4)Cl), X(m) was 4327 mg L(-1), a value almost coincident with that obtained with only 25.4 mM KNO(3), but more than twice that obtained with 21.5 mM NH(4)Cl. A 30%-reduction of culture medium cost can be estimated when compared to KNO(3)-batch runs, thus behaving as a cheap alternative for the commercial production of this cyanobacterium. (C) 2010 Elsevier Ltd. All rights reserved.

Screening of Variables Influencing the Clavulanic Acid Production by Streptomyces DAUFPE 3060 Strain

Clavulanic acid (CA) is a beta-lactam antibiotic, which has a potent beta-lactamase inhibiting activity. The influence of five variables, namely pH (6.0, 6.4, and 6.8), temperature (28A degrees C, 30A degrees C, and 32A degrees C), agitation intensity (150, 200, and 250 rpm), glycerol concentration (5.0, 7.5, and 10 g/L) and soybean flour concentration (5.0, 12.5, and 20 g/L), on CA production by a new isolate of Streptomyces (DAUFPE 3060) was investigated in 250-mL Erlenmeyer flasks using a fractional factorial design. Temperature and soybean flour concentration were shown to be the two variables that exerted the most important effects on the production of CA at 95% confidence level. The highest CA concentration (494 mg/L) was obtained after 48 h at 150 rpm, 32A degrees C, pH 6.0, 5.0 g/L glycerol, and 20 g/L soybean flour concentrations. Under these conditions, the yields of biomass and product on consumed substrate were 0.26 g(X)/g(S) and 64.3 mg(P)/g(S), respectively. Fermentations performed in 3.0-L bench-scale fermenter allowed increasing the CA production by about 60%.

Extraction of Ascorbate Oxidase from Cucurbita maxima by Continuous Process in Perforated Rotating Disc Contactor Using Aqueous Two-Phase Systems

The ascorbate oxidase is the enzyme used to determine the content of ascorbic acid in the pharmaceutical and food industries and clinics analyses. The techniques currently used for the purification of this enzyme raise its production cost. Thus, the development of alternative processes and with the potential to reduce costs is interesting. The application of aqueous two-phase system is proposed as an alternative to purification because it enables good separation of biomolecules. The objective of this study was to determine the conditions to continuously pre-purify the enzyme ascorbate oxidase by an aqueous two-phase system (PEG/citrate) using rotating column provided with perforated discs. Under the best conditions (20,000 g/mol PEG molar mass, 10% PEG concentration, and 25% citrate concentration), the system showed satisfactory results (partition coefficient, 3.35; separation efficiency, 54.98%; and purification factor, 1.46) and proved suitable for the pre-purification of ascorbate oxidase in continuous process.

Biogas production and valorization by means of a two-step biological process

The scope of this research work was to investigate biogas production and purification by a two-step bench-scale biological system, consisting of fed-batch pulse-feeding anaerobic digestion of mixed sludge, followed by methane enrichment of biogas by the use of the cyanobacterium Arthrospira platensis. The composition of biogas was nearly constant, and methane and carbon dioxide percentages ranged between 70.5-76.0% and 13.2-19.5%, respectively. Biogas yield reached a maximum value (about 0.4 m(biogas)(3)/kgCOD(i)) at 50 days-retention time and then gradually decreased with a decrease in the retention time. Biogas CO(2) was then used as a carbon source for A. platensis cultivation either under batch or fed-batch conditions. The mean cell productivity of fed-batch cultivation was about 15% higher than that observed during the last batch phase (0.035 +/- 0.006 g(DM)/L/d), likely due to the occurrence of some shading effect under batch growth conditions. The data of carbon dioxide removal from biogas revealed the existence of a linear relationship between the rates of A. platensis growth and carbon dioxide removal from biogas and allowed calculating carbon utilization efficiency for biomass production of almost 95%. (C) 2009 Elsevier Ltd. All rights reserved.

Sterilization of Medical Devices by Ethylene Oxide, Determination of the Dissipation of Residues, and Use of Green Fluorescent Protein as an Indicator of Process Control

Ethylene oxide (EO) is used to sterilize Oxygenator and Tubing applied to heart surgery. Residual levels of EO and its derivatives, ethylene chlorohydrin (ECH) and ethylene glycol (EG), may be hazardous to the patients. Therefore, it must be removed by the aeration process. This study aimed to estimate the minimum aeration time for these devices to attain safe limits for use (avoiding excessive aeration time) and to evaluate the Green Fluorescent Protein (GFP) as a biosensor capable of best indicating the distribution and penetration of EO gas throughout the sterilization chamber. Sterilization cycles of 2, 4, and 8 h were monitored by Bacillus atrophaeus ATCC 9372 as a biological indicator (131) and by the GFP. Residual levels of EO, ECH, and EG were determined by gas chromatography (GC), and the residual dissipation was studied. Safe limits were reached right after the sterilization process for Oxygenator and after 204 h of aeration for Tubing. In the 2 h cycle, the GFP concentration decreased from 4.8 (+/- 3.2)% to 7.5 (+/- 2.5)%. For the 4 h cycle, the GFP concentration decreased from 17.4 (+/- 3.0)% to 21.5 (+/- 6.8)%, and in the 8 h cycle, it decreased from 22.5 (+/- 3.2)% to 23.9 (+/- 3.9)%. This finding showed the potentiality for GFP applications as an EO biosensor. (C) 2009 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 9113: 626-630, 2009