High-pressure behavior of polyiodides confined into single-walled carbon nanotubes: A Raman study

International audienceThe high-pressure behavior of polyiodides confined into the hollow core of single-walled carbon nanotubes organized into bundles has been studied by means of Raman spectroscopy. Several regimes of the structural properties are observed for the nanotubes and the polyiodides under pressure. Raman responses of both compounds exhibit correlations over the whole pressure range (0–17 GPa). Modifications, in particular, take place, respectively, between 1 and 2.3 GPa for polyiodides and between 7 and 9 GPa for nanotubes, depending on the experiment. Differences between one experiment to another are discussed in terms of nanotube filling homogeneity. These transitions can be presumably assigned to the tube ovalization pressure and to the tube collapse pressure. A nonreversibility of several polyiodide mode modifications is evidenced and interpreted in terms of a progressive linearization of the iodine polyanions and a reduction in the charged species on pressure release. Furthermore, the significant change in the mode intensities could be associated to an enhancement of lattice modes, suggesting the formation of a new structure inside the nanotube. Changes in the nanotube mode positions after pressure release point out a decrease in the charge transfer in the hybrid system consistent with the observed evolution of the charged species

3 kirja Karl Morgensternile, Paris

http://tartu.ester.ee/record=b1826275~S1*es

High-pressure behavior of polyiodides confined into single-walled carbon nanotubes: A Raman study

International audienceThe high-pressure behavior of polyiodides confined into the hollow core of single-walled carbon nanotubes organized into bundles has been studied by means of Raman spectroscopy. Several regimes of the structural properties are observed for the nanotubes and the polyiodides under pressure. Raman responses of both compounds exhibit correlations over the whole pressure range (0–17 GPa). Modifications, in particular, take place, respectively, between 1 and 2.3 GPa for polyiodides and between 7 and 9 GPa for nanotubes, depending on the experiment. Differences between one experiment to another are discussed in terms of nanotube filling homogeneity. These transitions can be presumably assigned to the tube ovalization pressure and to the tube collapse pressure. A nonreversibility of several polyiodide mode modifications is evidenced and interpreted in terms of a progressive linearization of the iodine polyanions and a reduction in the charged species on pressure release. Furthermore, the significant change in the mode intensities could be associated to an enhancement of lattice modes, suggesting the formation of a new structure inside the nanotube. Changes in the nanotube mode positions after pressure release point out a decrease in the charge transfer in the hybrid system consistent with the observed evolution of the charged species

Recherche sur l'origine des fausses réactions positives dans le diagnostic sérologique de la péripneumonie contagieuse bovine

Des bovins ont été expérimentalement immunisés respectivement avec Mycoplasma (M) capricolum, M. mycoides subsp. mycoides (LC), M. mycoides subsp. capri, M. species groupe 7 de LEACH. Pendant 8 semaines ces animaux ont fait l'objet d'un suivi sérologique vis-à-vis de l'agent de la péripneumon ie contagieuse bovine (PPCB), par le test immunoenzymatique (ELISA), en fixation du complément (FC) et en hémagglutination passive (HAP), l'HAP étant effectuée également vis-à-vis des valences d'immunisation. En FC, utilisée selon la méthode standardisée, des réactions croisées, souvent transitoires, sont notées chez les bovins immunisés par le groupe 7 et les 2 "mycoides" caprins. Ce modèle experimental pourrait expliquer certaines réactions aspécifiques naturelles rencontrées exceptionnellement lors du diagnostic sérologique de la PPC

Motion frozen 18F-FDG cardiac PET

BackgroundPET reconstruction incorporating spatially variant 3D Point Spread Function (PSF) improves contrast and image resolution. "Cardiac Motion Frozen" (CMF) processing eliminates the influence of cardiac motion in static summed images. We have evaluated the combined use of CMF- and PSF-based reconstruction for high-resolution cardiac PET.MethodsStatic and 16-bin ECG-gated images of 20 patients referred for (18)F-FDG myocardial viability scans were obtained on a Siemens Biograph-64. CMF was applied to the gated images reconstructed with PSF. Myocardium to blood contrast, maximum left ventricle (LV) counts to defect contrast, contrast-to-noise (CNR) and wall thickness with standard reconstruction (2D-AWOSEM), PSF, ED-gated PSF, and CMF-PSF were compared.ResultsThe measured wall thickness was 18.9 ± 5.2 mm for 2D-AWOSEM, 16.6 ± 4.5 mm for PSF, and 13.8 ± 3.9 mm for CMF-PSF reconstructed images (all P < .05). The CMF-PSF myocardium to blood and maximum LV counts to defect contrasts (5.7 ± 2.7, 10.0 ± 5.7) were higher than for 2D-AWOSEM (3.5 ± 1.4, 6.5 ± 3.1) and for PSF (3.9 ± 1.7, 7.7 ± 3.7) (CMF vs all other, P < .05). The CNR for CMF-PSF (26.3 ± 17.5) was comparable to PSF (29.1 ± 18.3), but higher than for ED-gated dataset (13.7 ± 8.8, P < .05).ConclusionCombined CMF-PSF reconstruction increased myocardium to blood contrast, maximum LV counts to defect contrast and maintained equivalent noise when compared to static summed 2D-AWOSEM and PSF reconstruction

AS PROTEÍNAS DE FOLHA DE MANDIOCA: ASPECTOS FISIOLÓGICOS, NUTRICIONAIS E IMPORTÂNCIA TECNOLÓGICA

Some aspects of leaf proteins, specially from cassava (Manihot esculenta Crantz), as physiologic origin, amino acid composition, biochemical properties, nutritional role and technological process are reviewed. Cassava leaves present high protein content (20-30% w/w dry basis), of satisfactory quality when compared to FAO recommended pattern, and also high content of vitamins A and C and minerals. Some potential applications for human nutrition, animal feed or biotechnology industries are discussed. Alguns aspectos ligados à tecnologia de proteínas de folhas, com ênfase para as folhas de mandioca (Manihot esculenta Crantz), são revisados. A composição em aminoácidos, as propriedades bioquímicas, a importância nutricional e os princípios dos métodos de extração são apresentados. As folhas de mandioca apresentam elevado teor de proteínas (20-30% base seca), de valor nutricional adequado às recomendações da FAO, além de altos teores de vitaminas A e C e de minerais. Algumas aplicações potenciais em nutrição humana ou animal ou como substrato para a indústria de biotecnologia são discutidas

Topological mirror symmetry with fluxes

Motivated by SU(3) structure compactifications, we show explicitly how to construct half--flat topological mirrors to Calabi--Yau manifolds with NS fluxes. Units of flux are exchanged with torsion factors in the cohomology of the mirror; this is the topological complement of previous differential--geometric mirror rules. The construction modifies explicit SYZ fibrations for compact Calabi--Yaus. The results are of independent interest for SU(3) compactifications. For example one can exhibit explicitly which massive forms should be used for Kaluza--Klein reduction, proving previous conjectures. Formality shows that these forms carry no topological information; this is also confirmed by infrared limits and old classification theorems.Comment: 35 pages, 5 figure