1,481 research outputs found
Effect of the presence of two commercial adsorbents in animal feed on Aflatoxin B1 determination by ELISA kit test.
A rapid AFB1 detection method by ELISA kit test was used on feedstuff samples, and compared to an HPLC method, to verify if the presence of clay-adsorbent (SA) could cause erroneous quantification of the toxin. Samples were obtained using two AFB1-contaminated feedstuffs (7.92 and 17.58 µg/kg for low and high contaminated feeds; LC and HC respectively), added either one of two commercial SAs (Atox® and Myco AD) and three different inclusion doses (0, 10 and 20 g/kg, respectively for CTR, 1% and 2% doses). The HPLC and ELISA data were compared in CTR samples with a paired t-test. The AFB1 recoveries, performed with ELISA, were analysed as a completely randomized design using a 2×2×3 factorial arrangement. The ELISA method tended to underestimate the AFB1 concentrations with respect to the HPLC method, both in HC (P=0.050) and in LC (P<0.001) feedstuffs. A more drastic reduction (P<0.001) was observed when SAs were included in the two feedstuffs. In particular, Atox® determined an AFB1 recovery of 15,5% in HC and 7,6% in LC (1% dose) and of 11,1% in HC and 8,4% in LC (2% dose). Less severe penalisation were observed when Myco AD was added to feeds
Using mixed data in the inverse scattering problem
Consider the fixed- inverse scattering problem. We show that the zeros
of the regular solution of the Schr\"odinger equation, , which are
monotonic functions of the energy, determine a unique potential when the domain
of the energy is such that the range from zero to infinity. This
suggests that the use of the mixed data of phase-shifts
, for which the zeros of the regular solution are monotonic in both domains,
and range from zero to infinity, offers the possibility of determining the
potential in a unique way.Comment: 9 pages, 2 figures. Talk given at the Conference of Inverse Quantum
Scattering Theory, Hungary, August 200
Caracterização da matéria orgânica de solos da região amazônica empregando a espectroscopia de fluorescência induzida por laser e a espectroscopia de emissão óptica com plasma induzido por laser.
Entrada padronizada de BOAS, P. R. V.; MARTIN NETO, L
Comparison of algorithms for baseline correction of LIBS spectra for quantifying total carbon in Brazilian soils.
LIBS is a promising and versatile technique for multi-element analysis that
usually takes less than a minute and requires minimal sample preparation and no
reagents. Despite the recent advances in elemental quantification, the LIBS
still faces issues regarding the baseline produced by background radiation,
which adds non-linear interference to the emission lines. In order to create a
calibration model to quantify elements using LIBS spectra, the baseline has to
be properly corrected. In this paper, we compared the performance of three
filters to remove random noise and five methods to correct the baseline of LIBS
spectra for the quantification of total carbon in soil samples. All
combinations of filters and methods were tested, and their parameters were
optimized to result in the best correlation between the corrected spectra and
the carbon content in a training sample set. Then all combinations with the
optimized parameters were compared with a separate test sample set. A
combination of Savitzky-Golay filter and 4S Peak Filling method resulted in the
best correction: Pearson's correlation coefficient of 0.93 with root mean
square error of 0.21. The result was better than using a linear regression
model with the carbon emission line 193.04 nm (correlation of 0.91 with error
of 0.26). The procedure proposed here opens a new possibility to correct the
baseline of LIBS spectra and to create multivariate methods based on the a
given spectral range.Comment: 13 pages, 5 figure
Black garlic: transformation effects, characterization and consumer purchase intention.
The aim of this study was to evaluate quality and nutritional changes on bulbs before and after the transformation in black garlic, presenting the new product for the consumer, evaluating the purchase intention
Anisotropic diffusion in continuum relaxation of stepped crystal surfaces
We study the continuum limit in 2+1 dimensions of nanoscale anisotropic
diffusion processes on crystal surfaces relaxing to become flat below
roughening. Our main result is a continuum law for the surface flux in terms of
a new continuum-scale tensor mobility. The starting point is the Burton,
Cabrera and Frank (BCF) theory, which offers a discrete scheme for atomic steps
whose motion drives surface evolution. Our derivation is based on the
separation of local space variables into fast and slow. The model includes: (i)
anisotropic diffusion of adsorbed atoms (adatoms) on terraces separating steps;
(ii) diffusion of atoms along step edges; and (iii) attachment-detachment of
atoms at step edges. We derive a parabolic fourth-order, fully nonlinear
partial differential equation (PDE) for the continuum surface height profile.
An ingredient of this PDE is the surface mobility for the adatom flux, which is
a nontrivial extension of the tensor mobility for isotropic terrace diffusion
derived previously by Margetis and Kohn. Approximate, separable solutions of
the PDE are discussed.Comment: 14 pages, 1 figur
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