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81.
Silva ME Firmino PI Sousa MR Santos AB 《Applied biochemistry and biotechnology》2012,166(4):1057-1069
Colour and COD removals of the azo dyes Congo Red (CR) and Reactive Black 5 (RB5) were individually evaluated in a sequential
anaerobic/aerobic treatment system. Additionally, dye toxicity was assessed by using acute ecotoxicity tests with Daphnia magna as the indicator-organism. The anaerobic reactor was operated at approximately 27 °C and with hydraulic retention times of
12 and 24 h. The aerobic reactor was operated in batch mode with a total cycle of 24 h. During anaerobic step, high colour
removals were obtained, 96.3% for CR (400 mg/L) and 75% for RB5 (200 mg/L). During the aerobic phase, COD effluent was considerably
reduced, with an average removal efficiency of 52% for CR and 85% for RB5, which resulted in an overall COD removal of 88%
for both dyes. Ecotoxicity tests with CR revealed that the anaerobic effluent presented a higher toxicity compared with the
influent, and an aerobic post-treatment was not efficient in reducing toxicity. However, the results with RB5 showed that
both anaerobic and aerobic steps could decrease dye toxicity, especially the aerobic phase, which removed completely the toxicity
in D. magna. Therefore, the anaerobic/aerobic treatment is not always effective in detoxifying dye-containing wastewaters, sometimes
even increasing dye toxicity. 相似文献
82.
da Silva CD Coriolano MC da Silva Lino MA de Melo CM de Souza Bezerra R de Carvalho EV Dos Santos AJ Pereira VR Coelho LC 《Applied biochemistry and biotechnology》2012,166(2):424-435
The aim of this work was to purify and partially characterize a mannose recognition lectin from Nile tilapia (Oreochromis niloticus) serum, named OniL. OniL was isolated through precipitation with ammonium sulfate and affinity chromatography (Concanavalin
A–Sepharose 4B). In addition, we evaluated carbohydrate specificity, sodium dodecyl sulfate polyacrylamide gel electrophoresis
(SDS–PAGE) profiles, and in vitro immunomodulatory activity on mice splenocyte experimental cultures through cytotoxic assays
and cytokine production. The ammonium sulfate fraction F2 showed the highest specific hemagglutinating activity (331) and
was applied to affinity matrix. Adsorbed proteins (OniL) were eluted with methyl-α-d-mannopyranoside. OniL, a 17-kDa protein by SDS–PAGE constituted by subunits of 11 and 6.6 kDa, showed highest affinity for
methyl-α-d-mannopyranoside and d-mannose. Immunological assays, in vitro, showed that OniL did not show cytotoxicity against splenocytes, induced higher IFN-γ
production and lower IL-10 as well as nitrite release. In conclusion, OniL lectin was successfully purified and showed a preferential
Th1 response in mice splenocytes. 相似文献
83.
Juliana Cristina Barreiro Tânia Vieira Madureira Maria Elizabeth Tiritan Quezia Bezerra Cass 《Talanta》2010,82(1):384-4648
This work reports the use of a two-dimensional liquid chromatography (2D-LC) system for quantification of the enantiomers of omeprazole in distinct native aqueous matrices. An octyl restricted-access media bovine serum albumin column (RAM-BSA C8) was used in the first dimension, while a polysaccharide-based chiral column was used in the second dimension with either ultraviolet (UV-vis) or ion-trap tandem mass spectrometry (IT-MS/MS) detection. An in-line configuration was employed to assess the exclusion capacity of the RAM-BSA columns to humic substances. The excluded macromolecules had a molecular mass in the order of 18 kDa. Good selectivity, extraction efficiency, accuracy, and precision were achieved employing a very small amount (500 μL or 1.00 mL) of native water sample per injection, with detection limits of 5.00 μg L−1, using UV-vis, and 0.0250 μg L−1, using IT-MS/MS. The total analysis time was only 35 min, with no time spent on sample preparation. The methods were successfully applied to analyze a series of waste and estuarine water samples. The enantiomers were detected in an estuarine water sample collected from the Douro River estuary (Portugal) and in an influent sample from the wastewater treatment plant (WWTP) of São Carlos (Brazil). As far as we are concerned, this is the first report of the occurrence of (+)-omeprazole and (−)-omeprazole in native aqueous matrices. 相似文献
84.
Rodrigo Amorim Bezerra da Silva Adriano César Rabelo Rodrigo Alejandro Abarza Munoz Eduardo Mathias Richter 《Electroanalysis》2010,22(19):2167-2171
This work describes the construction, characterization, and application of a three‐electrode‐integrated sensor into a micropipette tip. The three electrodes (working, pseudoreference and counter) are positioned at the end of a micropipette tip. The working electrode (graphite composite or gold microfiber) is placed inside the micropipette tip and the pseudo‐reference and counter electrodes outside (diametrically opposed sides). This approach is candidate for portable applications and allows the analysis and studies in low‐volume solutions (ca. 10 µL) which are useful for waste minimization and development of clean analytical methods. In addition, the three‐electrode‐integrated sensor can be easy used as detector in flow injection system through its direct joining at the end of polyethylene tubing of the FIA system. 相似文献
85.
A compact miniaturized continuous flow system for the determination of urea content in milk 总被引:1,自引:0,他引:1
Willian Toito Suarez Osmundo Dantas Pessoa-Neto Vagner Bezerra dos Santos Ana Rita de Araujo Nogueira Ronaldo Censi Faria Orlando Fatibello-Filho Mar Puyol Julián Alonso 《Analytical and bioanalytical chemistry》2010,398(3):1525-1533
A multicommutation-based flow system with photometric detection was developed, employing an analytical microsystem constructed
with low temperature co-fired ceramics (LTCC) technology, a solid-phase reactor containing particles of Canavalia ensiformis DC (urease source) immobilized with glutaraldehyde, and a mini-photometer coupled directly to the microsystem which monolithically
integrates a continuous flow cell. The determination of urea in milk was based on the hydrolysis of urea in the solid-phase
reactor and the ammonium ions produced were monitored using the Berthelot reaction. The analytical curve was linear in the
urea concentration range from 1.0 × 10−4 to 5.0 × 10−3 mol L−1 with a limit of detection of 8.0 × 10−6 mol L−1. The relative standard deviation (RSD) for a 2.0 × 10−3 mol L−1 urea solution was lower than 0.4% (n = 10) and the sample throughput was 13 h−1. To check the reproducibility of the flow system, calibration curves were obtained with freshly prepared solutions on different
days and the RSD obtained was 4.7% (n = 6). Accuracy was assessed by comparing the results of the proposed method with those from the official procedure and the
data are in close agreement, at a 95% confidence level. 相似文献
86.
A procedure has been developed for the simultaneous determination of traces amounts of Cd, Cr, Cu, Mn, Ni and Pb from saline oil-refinery effluents and digested vegetable samples using inductively coupled plasma optical emission spectrometry (ICP OES). The procedure is based on cloud point extraction (CPE) of these metals as 2-(bromo-2-pyridylazo)-5-diethyl-amino-phenol (Br-PADAP) complexes into a micellar phase of octylphenoxypolyethoxyethanol (Triton X-114). Optimization of the procedure was performed by response surface methodology (RSM) using a Doehlert design. Principal components (PC) were used to simplify the multiple response analysis. A response surface for the first PC score is useful in determining the optimum conditions for the Cd, Cr, Cu, Mn and Pb determinations whereas the second PC is highly correlated with the Ni response. Improvement factors of 22, 36, 46, 25, 65 and 39, along with limits of detection (3σB) of 0.081, 0.79, 0.38, 0.83, 0.28 and 0.69 μg L−1, and precision expressed as relative standard deviation (%R.S.D., n = 8, 20.0 μg L−1) of 1.5, 2.2, 3.5, 2.6, 2.5 and 2.5 were achieved for Cd, Cr, Cu, Mn, Ni and Pb, respectively. The accuracy was evaluated by spike tests in oil-refinery effluent samples and analysis of a vegetable certified reference material (NIST 1571, orchard leaves). Results found were in agreement with certified values. 相似文献
87.
We address the spin wave modes propagating in Fibonacci, Thue–Morse, and double period quasiperiodic magnonic superlattices. These structures are made of layers of a metamagnetic material alternating with layers of a nonmagnetic material, presenting mirror symmetry. Our calculations are carried out in the magnetostatic regime for the antiferromagnetic phase. Our model takes into account the presence of an external applied magnetic field, which is perpendicular to the interfaces of the superlattice, as well as the crystalline anisotropic contribution to the inner magnetic field. The magnetostatic bulk and surface modes are obtained by using the transfer matrix technique. The metamagnetic material considered here is FeBr2, however, our results can be extended to other materials. Our numerical results show the behavior of these modes, for small frequencies of the energy spectra. The results reported here can be experimentally observed by light scattering techniques. 相似文献
88.
Marta M. Conceição V. J. Fernandes Jr A. F. Bezerra M. C. D. Silva Iêda M. G. Santos F. C. Silva A. G. Souza 《Journal of Thermal Analysis and Calorimetry》2007,87(3):865-869
Diesel oil has an important role in the field
of urban traffic as well as in the transportation of products. However, the
amount of the non-renewable sources is continuously decreasing. This fact
and the environmental requirements brought the necessity to search for other,
renewable sources. This paper aimed the dynamic kinetic calculation of thermal
decomposition of castor oil, methanol biodiesel and ethanol biodiesel using
Coats–Redfern, Madhusudanan and Ozawa methods. On the base of the thermogravimetric
curves the following thermal stability order could be established: castor
oil>ethanol biodiesel>methanol biodiesel. Kinetic data presented coherent
results. Methanol biodiesel presented lower activation energy than ethanol
biodiesel, suggesting that methanol biodiesel has a better quality for combustion. 相似文献
89.
Taking in consideration the global analysis of complex samples, proposed by the metabolomic approach, the chromatographic
fingerprint encompasses an attractive chemical characterization of herbal medicines. Thus, it can be used as a tool in quality
control analysis of phytomedicines. The generated multivariate data are better evaluated by chemometric analyses, and they
can be modeled by classification methods. “Stone breaker” is a popular Brazilian plant of Phyllanthus genus, used worldwide to treat renal calculus, hepatitis, and many other diseases. In this study, gradient elution at reversed-phase
conditions with detection at ultraviolet region were used to obtain chemical profiles (fingerprints) of botanically identified
samples of six Phyllanthus species. The obtained chromatograms, at 275 nm, were organized in data matrices, and the time shifts of peaks were adjusted
using the Correlation Optimized Warping algorithm. Principal Component Analyses were performed to evaluate similarities among
cultivated and uncultivated samples and the discrimination among the species and, after that, the samples were used to compose
three classification models using Soft Independent Modeling of Class analogy, K-Nearest Neighbor, and Partial Least Squares for Discriminant Analysis. The ability of classification models were discussed
after their successful application for authenticity evaluation of 25 commercial samples of “stone breaker.” 相似文献
90.
Delatorre P Rocha BA Simões RC Pereira-Júnior FN Silva HC Bezerra EH Bezerra MJ Marinho ES Gadelha CA Santi-Gadelha T Farias DL Assreuy AM Marques-Domingos GF Nagano CS Cavada BS 《Applied biochemistry and biotechnology》2011,164(6):741-754
The lectin from seeds of Dioclea virgata (DvirL) was purified in a single step affinity chromatography, sequenced by tandem mass spectrometry and submitted to crystallization and biological experiments. DvirL has a molecular mass of 25,412?±?2 Da and the chains β and γ has 12,817 Da?±?2 and 12,612 Da?±?2, respectively. Primary sequence determination was assigned by tandem mass spectrometry and revealed a protein with 237 amino acids and 87% of identify with ConA. The protein crystals were obtained native and complexed with X-Man using vapor-diffusion method at a constant temperature of 293 K. A complete X-ray dataset was collected at 1.8 ? resolution. DvirL crystals were found to be orthorhombic, belonging to the space group I222, with a unit cell parameters a?=?647.5 ?, b?=?86.6 ?, c?=?90.2 ?. Molecular replacement search found a solution with a correlation coefficient of 77.1% and an R(factor) of 44.6%. The present study also demonstrated that D. virgata lectin presents edematogenic and antinociceptive activities in rodents electing this protein as a candidate to structure/function analysis. 相似文献