Measurement of partial widths and search for direct CP violation in D0 meson decays to K-K+ and pi-pi+

We present a measurement of relative partial widths and decay rate CP asymmetries in K-K+ and pi(-)pi(+) decays of D0 mesons produced in pp collisions at sqrt[s]=1.96 TeV. We use a sample of 2x10(5) D(*+)-->D0pi(+) (and charge conjugate) decays with the D0 decaying to K-pi(+), K-K+, and pi(-)pi(+), corresponding to 123 pb(-1) of data collected by the Collider Detector at Fermilab II experiment at the Fermilab Tevatron collider. No significant direct CP violation is observed. We measure Gamma(D0-->K-K+)/Gamma(D0-->K-pi(+))=0.0992+/-0.0011+/-0.0012, Gamma(D0-->pi(-)pi(+))/Gamma(D0-->K-pi(+))=0.035 94+/-0.000 54+/-0.000 40, A(CP)(K-K+)=(2.0+/-1.2+/-0.6)%, and A(CP)(pi(-)pi(+))=(1.0+/-1.3+/-0.6)%, where, in all cases, the first uncertainty is statistical and the second is systematic.     

A parametric imaging approach for the segmentation of ultrasound data

When an ultrasonic examination is performed, a segmentation tool would often be very useful, either for the detection of pathologies, the early diagnosis of cancer or the follow-up of the lesions. Such a tool must be both reliable and accurate. However, because of the relatively reduced quality of ultrasound images due to the speckled texture, the segmentation of ultrasound data is a difficult task. We have previously proposed to tackle the problem using a multiresolution Bayesian region-based algorithm. For computation time purposes, a multiresolution version has been implemented. In order to improve the quality of the segmentation, we propose to perform the segmentation not only from the envelope image but to combine more information about the properties of the tissues in the segmentation process. Several acoustical parameters have thus been computed, either directly from the images or from the radio-frequency (RF) signal.

In a previous study, two parametric images were involved in the segmentation process. The parameter represented the integrated backscatter (IBS) and the mean central frequency (MCF), which is a measurement related to the attenuation of ultrasound waves in the media. In this study, parameters representative of the scattering conditions in the tissue are evaluated in the multiparametric segmentation process. They are extracted from the K-distribution (,b) and the Nakagami distribution (m,Ω) and are related to the local density of scatterers (,m), the size of the scatterers (b) and the backscattering properties of the medium (Ω).

The acoustical features are calculated locally on a sliding window. This procedure allows to built parametric mapping representing the particular characteristics of the medium. To test the influence of the acoustical parameters in the segmentation process, a set of numerical phantoms has been computed using the Field software developed by J.A. Jensen. Each phantom consists in two regions with two different acoustical properties: the density of scatterers and the scattering amplitude. From both the simulated RF signals and envelope images, the parameters have been computed; their relevance to represent a particular characteristic of the medium is evaluated. The segmentation has been processed for each phantom. The ability of each parameter to improve the segmentation results is validated. A agar–gel phantom has also been created, in order to test the accuracy of the parameters in conditions closer to the in vivo ultrasound imaging. This phantom contains four inclusions with different concentrations of silica. A B&K ultrasound device provides the RF data. The quantification of the segmentation quality is based on the rate of correctly classified pixels and it has been computed for all the parameters either from the field images or the phantom images. The large improvement in the segmentation results obtained reveals that the multiparametric segmentation scheme proposed in this study can be a reliable tool for the processing of noisy ultrasound data.     

Development and validation of an at-line fast and non-destructive Raman spectroscopic method for the quantification of multiple components in liquid detergent compositions

Implementation of process analytical technology (PAT) tools in the manufacturing process of liquid detergent compositions should allow fast and non-destructive evaluation of the product quality. The aim of this study was to develop and validate a rapid method for quantifying the chemical compounds of five washing liquid precursors. Raman spectroscopy was applied in combination with a two-step multivariate modeling procedure. In first instance, a SIMCA (Soft Independent Modeling of Class Analogy) model was developed and validated, allowing the distinction between the different laundry detergents. Once the product was correctly identified, it was aimed at predicting the concentration of its individual components using partial least squares (PLS) models. Raman spectra were collected at-line with a total acquisition time of 20 s, using a non-contact fiber-optic probe.     

Influence of the compatibilizer polarity and molar mass on the morphology and the gas barrier properties of polyethylene/clay nanocomposites

In this study, different modified polyethylenes with different molar masses and different modification rates were examined as compatibilizers to prepare high density polyethylene/organoclay nanocomposites. Nanocomposites having 5 wt % organo-modified clay and 20 wt % interfacial agent were prepared by melt blending. The effect of compatibilizer molar mass and polarity was investigated on the clay dispersion and on the gas barrier properties. It was observed that the amount of large and dense fillers aggregates was considerably reduced by introduction of an interfacial agent. The nanocomposite final morphology was governed by a diffusion/shear mechanism. A high degree of clay delamination was obtained with the high molar mass compatibilizers, whereas highly swollen clay aggregates resulted from the incorporation of the low molar mass interfacial agents. In the investigated nanocomposites series, the barrier properties could not be directly related to the clay dispersion state but resulted also from the matrix/clay interfacial interactions. A gas transport mechanism based on these both parameters was proposed to explain the barrier properties evolution in these low polar nanocomposites series. © 2008 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 46: 2593–2604, 2008     

A new certified reference material for benzene measurement in air on a sorbent tube: development and proficiency testing

A certified matrix reference material (CRM) for the measurement of benzene in ambient air has been developed at Laboratoire National de Métrologie et d’Essais. The production of these CRMs was conducted using a gravimetric method fully traceable to the International System of Units. The CRMs were prepared by sampling an accurate mass of a gaseous primary reference material of benzene, using a high-precision laminar flowmeter and a mass flow controller, with a PerkinElmer sampler filled with Carbopack™ X sorbent. The relative standard deviations obtained for the preparation of a batch of 20 tubes loaded with 500 ng of benzene were below 0.2%. Each CRM is considered independent from the others and with its own certified value and an expanded uncertainty estimated to be within 0.5%, lower than the uncertainties of benzene CRMs already available worldwide. The stability of these materials was also established up to 12 months. These CRMs were implemented during proficiency testing, to evaluate the analytical performances of seven French laboratories involved in benzene air monitoring.     

Highly flexible and efficient top-emitting organic light-emitting devices with ultrasmooth Ag anode

We demonstrate highly flexible and efficient top-emitting organic light-emitting devices (TOLEDs) by using an ultrasmooth Ag anode. A template-stripping process has been employed to create the ultrasmooth Ag anode on a photopolymer substrate. The flexible TOLEDs obtained by this method keep good electroluminescence properties under a small bending radius and after repeated bending. The efficiency of the flexible TOLEDs is improved by 60% compared with the conventional TOLEDs deposited on Si substrate due to the enhanced hole injection from the ultrasmooth anode.     

Upper critical magnetic field far above the paramagnetic pair-breaking limit of superconducting one-dimensional Li0:9Mo6O17 single crystals

The upper critical field H(c2) of purple bronze Li0:9Mo6O17 is found to exhibit a large anisotropy, in quantitative agreement with that expected from the observed electrical resistivity anisotropy. With the field aligned along the most conducting axis, H(c2) increases monotonically with decreasing temperature to a value 5 times larger than the estimated paramagnetic pair-breaking field. Theories for the enhancement of H(c2) invoking spin-orbit scattering or strong-coupling superconductivity are shown to be inadequate in explaining the observed behavior, suggesting that the pairing state in Li0:9Mo6O17 is unconventional and possibly spin triplet.     

Solvent influence on the photophysical properties of 4-methoxy-N-methyl-1,8-naphthalimide

4-Methoxy-N-methyl-1,8-naphthalimide (1) exhibits considerable solvatochromism and its UV-vis spectral properties have been studied in several polar/non-polar and protic/aprotic solvents, as well as in ethanol-water mixtures. The results reveal a strong influence of the solvent's polarity and its hydrogen-bond donor (HBD) capability on the photophysical properties of 1. For binary ethanol/water mixtures, preferential solvation models describe the band shifts in the probe's visible absorption spectrum well, but they fail to describe the corresponding shifts of the emission maxima. Pseudolinear approximations between solvent composition and molecule's transition energies, E(T), can be used to study the composition of ethanol-water mixtures, simplifying the mathematical treatment for eventual analytical applications.     

Evidence of a two-stage thermal denaturation process in lysozyme: a Raman scattering and differential scanning calorimetry investigation

Raman spectroscopy (in the low-frequency range and the amide I band region) and modulated differential scanning calorimetry investigations have been used to analyze temperature-induced structural changes in lysozyme dissolved in 1H2O and 2H2O in the thermal denaturation process. Low-frequency Raman data reveal a change in tertiary structure without concomitant unfolding of the secondary structure. Calorimetric data show that this structural change is responsible for the configurational entropy change associated with the strong-to-fragile liquid transition and correspond to about 1/3 of the native-denaturated transition enthalpy. This is the first stage of the thermal denaturation which is a precursor of the secondary structure change and is determined to be strongly dependent on the stability of the hydrogen-bond network in water. Low-frequency Raman spectroscopy provides information on the flexibility of the tertiary structure (in the native state and the transient folding state) in relation to the fragility of the mixture. The unfolding of the secondary structure appears as a consequence of the change in the tertiary structure and independent of the solvent. Protein conformational stability is directly dependent on the stability of the native tertiary structure. The structural transformation of tertiary structure can be detected through the enhanced 1H/2H exchange inhibited in native proteins. Taking into account similar features reported in the literature observed for different proteins it can be considered that the two-stage transformation observed in lysozyme dissolved in water is a general mechanism for the thermal denaturation of proteins.