Structural and morphological studies on the deformation behavior of polypropylene/multi‐walled carbon nanotubes nanocomposites prepared through ultrasound‐assisted melt extrusion process

Structural and morphological behavior under stress–strain of polypropylene/multi‐walled carbon nanotubes (PP/MWCNTs) nanocomposites prepared through ultrasound‐assisted melt extrusion process was studied by means of optical microscopy, scanning electron microscopy, transmission electron microscopy, Raman spectroscopy, small angle X‐ray scattering (SAXS), and wide angle X‐ray scattering (WAXS). A high ductile behavior was observed in the PP/MWCNT nanocomposites with low concentration of MWCNTs. This was related to an energy‐dissipating mechanism, achieved by the formation of an ordered PP‐CNTs interphase zone and crystal oriented structure in the undeformed samples. Different strain‐induced‐phase transformations were observed by ex situ SAXS/WAXS, characterizing the different stages of structure development during the deformation of PP and PP/MWCNTs nanocomposites. The high concentration of CNTs reduced the strain behavior of PP due to the agglomeration of nanoparticles. A structural pathway relating the deformation‐induced phase transitions and the dissipation energy mechanism in the PP/MWCNTs nanocomposites at low concentration of nanoparticles was proposed. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2015 , 53, 475–491     

Simultaneous analysis by capillary electrophoresis of five amyloid peptides as potential biomarkers of Alzheimer's disease

We report here a CE method for the separation and quantitation of five amyloid peptides (Abeta1-42, 1-40, 1-39, 1-38, and 1-37) considered as potential biomarkers of Alzheimer's disease. These amyloid peptides have very similar structures. Sample preparation and storage conditions are critical parameters to ensure their solubility and to avoid the aggregation process in particular for Abeta1-42. Their solubility was found fully dependent on the NH(4)OH concentration that was employed initially to dissolve the lyophilized amyloid peptides. Conditions to achieve a full separation of these peptides were found using a dynamic coating with 1,4-diaminobutane (DAB). The linear decrease of their electrophoretic mobility highlighted an ion-pairing phenomenon between the peptides and DAB. The optimal background electrolyte was a 40 mM borate buffer, pH 9 containing 3 mM of DAB. Under these conditions, resolutions ranged from 1.3 to 2.4 with theoretical plates reaching 300,000. Under the retained conditions, we showed that adsorption of peptides to silica was negligible (recovery over 94.5%) and depletion effect of the background electrolyte was overcome. The method was finally validated in terms of linearity and repeatability and the limits of detection for the five Abeta peptides were estimated. The inter-day repeatability of the migration times was very satisfactory with RSDs less than 1.55%. The RSDs of the peak areas were below 5%. With this CE-UV method, limits of detection of the peptides ranged from 300 to 500 nM. We finally demonstrated that this method can be applied to real biological samples such as CSF.     

A wave automaton for Maxwell's equations

This paper presents an extension to electromagnetic fields of the wave automaton, which was introduced in recent years for describing wave propagation in inhomogeneous media. Using elementary processes obeying a discrete Huygens' principle and satisfying fundamental symmetries such as time reversal and reciprocity, this new wave automaton is capable of modeling Maxwell's equations in 3+1 dimensions. It supplements the methods that were developed early for scalar and spinor fields. Received 19 July 2001     

Brute-force orientation of178m 2Hf and magnetic moments of178m 1Hf and178m 2Hf

Gamma-ray anisotropy measurements have been carried out with brute-force oriented^178m ₂Hf (16⁺) to derive its magnetic moment 7.26 (±0.16; +0.2/−0) nm and E2/M1 mixing ratios of some γ-transitions observed in the decay of this isomer. This magnetic moment is in agreement with an earlier proposed four-quasi-particle configuration. The magnetic moment of the 8⁻ isomer at 1147.7 keV (4.0 s) is estimated to be between 1.4 and 5.3 nm, which confirms mixing of the {p[514]9/2 +p[404]7/2}8⁻ and {n[514]7/2+n[624]9/2}8⁻ configurations, which summed together give the 16⁺ isomer.     

Maximum directed cuts in digraphs with degree restriction

For integers m, k≥1, we investigate the maximum size of a directed cut in directed graphs in which there are m edges and each vertex has either indegree at most k or outdegree at most k. © 2009 Wiley Periodicals, Inc. J Graph Theory     

Synthesis of novel alkylamino zinc(II) phthalocyanines

The synthesis of tetramethyl‐tetraphthalimidomethyl‐phthalocyaninato zinc(II) ( 6 ) and tetramethyl‐tetraaminomethyl‐phthalocyaninato zinc(II) ( 7 ) is described.     

In-beam orientation of low energy mass-separated radioactive beams: Development of the technique and first results

We report on the first results obtained with a system designed to polarize on-line mass-separated radioactive ion beams by scattering the beams from very flat single crystal surfaces at grazing incidence angles. Polarizations of 1 to 2% were already observed for deuterium.