Search results for " Specificity"
showing 10 items of 2170 documents
NATURAL SELECTION AND THE ORGAN-SPECIFIC DIFFERENTIATION OF HIV-1 V3 HYPERVARIABLE REGION
2004
The existence of organ-specific HIV-1 populations within infected hosts has been studied for many years; nonetheless results reported by different authors are somewhat discrepant. To tackle this problem, we used a population genetics approach to analyze previously published data from the V3 hypervariable region of the envelope env gene. Our results are compatible with a population subdivision by organs in 95% of individuals analyzed at autopsy. In addition, populations infecting the nervous system and testicles clearly appear as differentiated subsets of the so-called macrophage-tropic variants. Liver and kidney may harbor differentiated populations as well. Although it is widely accepted t…
Propagation pattern analysis during atrial fibrillation based on the adaptive group LASSO.
2012
The present study introduces sparse modeling for the estimation of propagation patterns in intracardiac atrial fibrillation (AF) signals. The estimation is based on the partial directed coherence (PDC) function, derived from fitting a multivariate autoregressive model to the observed signals. A sparse optimization method is proposed for estimation of the model parameters, namely, the adaptive group least absolute selection and shrinkage operator (aLASSO). In simulations aLASSO was found superior to the commonly used least-squares (LS) estimation with respect to estimation performance. The normalized error between the true and estimated model parameters dropped from 0.200.04 for LS estimatio…
Sensitivity enhancement in pulse EPR distance measurements
2004
Established pulse EPR approaches to the measurement of small dipole-dipole couplings between electron spins rely on constant-time echo experiments to separate relaxational contributions from dipolar time evolution. This requires a compromise between sensitivity and resolution to be made prior to the measurement, so that optimum data are only obtained if the magnitude of the dipole-dipole coupling is known beforehand to a good approximation. Moreover, the whole dipolar evolution function is measured with relatively low sensitivity. These problems are overcome by a variable-time experiment that achieves suppression of the relaxation contribution by reference deconvolution. Theoretical and exp…
Improvement of ESR dosimetry for thermal neutron beams through the addition of gadolinium.
2007
In this paper, the addition of gadolinium is proposed as a useful tool to enhance the electron spin resonance (ESR) sensitivity of organic compounds to thermal neutrons. The target of this work is the detection, through the ESR technique, of the thermal neutron fluence in a mixed field of photons and neutrons. Gadolinium was chosen because it has a very high capture cross section to thermal neutrons; its nuclear reaction with thermal neutrons induces complex inner shell transitions that generate, besides other particles, Auger electrons, which in turn release their energy in the neighborhood (only several nanometers) of the place of reaction. Gadolinium was added to two organic molecules: a…
CHEMICAL AND PHYSICAL SIGNALS MEDIATING CONSPECIFIC AND HETEROSPECIFIC AGGREGATION BEHAVIOR OF FIRST INSTAR STINK BUGS
2004
We investigated cues that mediate the aggregation behavior of immature pentatomid bugs by using nymphs of six different pentatomid bug species (Nezara viridula, Acrosternum hilare, Chlorochroa ligata, Chlorochroa sayi, Thyanta pallidovirens, and Euschistus conspersus). When first instars of any two species were put together in a Petri dish, they readily formed heterospecific aggregations similar to their natural conspecific aggregations. The chemical profiles of first and second instar nymphs of each species were determined by solvent extraction with pentane, followed by GC-MS analysis. Immature bugs of the different species had some compounds in common, and some that were more species spec…
Identification of a lysyl residue defining the binding specificity of a human odorant-binding protein
2008
International audience
Bermanella marisrubri gen. nov., sp. nov., a genome-sequenced gammaproteobacterium from the Red Sea
2009
5 pages, 2 figures, 1 table
Natural co-occurrence of ochratoxin A, ochratoxin B and aflatoxins in Sicilian red wines
2015
The natural occurrence of ochratoxin A, ochratoxin B, aflatoxin B1, aflatoxin B2, aflatoxin G1 and aflatoxin G2 (OTA, OTB, AFB1, AFB2, AFG1, AFG2) in red wines was investigated by HPLC/FLD after immunoaffinity column clean-up in 57 market samples produced in Sicily (Italy). The results showed a very low incidence of these mycotoxins in analysed samples, confirming the high degree of quality and safety of Sicilian red wines. The results indicated 71.9% and 64.9% positive samples for OTA and OTB respectively, with an average level of 0.13 μg l(-1), well below the European maximum permitted levels (MLs). The aflatoxin most frequently detected in the samples was AFG1, present in 57.9% of sample…
Simultaneous detection of the main black aspergilli responsible for ochratoxin A (OTA) contamination in grapes by multiplex real-time polymerase chai…
2009
9 pages.
Rapid determination of ochratoxin A in cereals and cereal products by liquid chromatography.
2004
A new method based on extraction with octylsilica (C8) followed by liquid chromatography coupled with fluorescence detection (LC-FLD) was studied to determine ochratoxin A (OTA) from cereals and cereal products. Optimization of different parameters, such as type and amount of solid phase, type and volume of eluent and amount of sample were carried out. Recovery of OTA from rice samples spiked at 10 ng/g level was of 86% with relative standard deviation of 5%. The limits of detection and quantification of the proposed method were 0.25 and 0.75 ng/g, respectively. Furthermore, LC-FLD after of OTA methylation and liquid chromatography coupled to mass spectrometry with an electrospray interface…