PS‐b‐PMA block copolymers carrying terminal anionic groups have been studied. Their synthesis is achieved by mean of 3‐(benzylsulfanyl thiocarbonylsulfanyl) propionic acid and ...3‐(1‐phenylethylsulfanyl thiocarbonylsulfanyl) propanesulfonic acid sodium salt as RAFT agents. These block copolymers, when dispersed in methanol, display a pseudo‐amphiphilic behaviour and provide micelles that can be suspended in water by osmosis. During the self‐assembling process, the anionic terminations lead to the formation of nanosized monodispersed particles and confer stability to the micelles in aqueous media. The core of the micelles is loaded with Nile Red to achieve the intracellular delivery of a lipophilic substance; this has been demonstrated by Confocal Laser Scanning Microscopy. The particles, when loaded with Doxorubicin, are able to overcome the intrinsic resistance of LoVo‐MDR cancer cells. A further stabilization is given to the micelles by covalent shell crosslinking provided by triethylene glycol diacrylate. The increased intracellular stability of the crosslinked micelles makes them stain, when loaded with Nile Red, the aqueous cytosol instead of the lipophilic cellular compartments. The unimers constituting the micelles have been covalently labelled with fluorescein to follow their fate once incorporated into the cells.
Many early-type stars are in systems; some of them have been indicated as putative high-energy emitters. The radiation is expected to be produced at the region where two stellar winds collide. ...Compelling evidence of such emission was found only for the colliding-wind binary (CWB) Eta Car, which was associated to a GeV source. Very recently, the closest CWB, WR 11, was proposed as a counterpart of a 6sigma emission excess, measured with the Fermi LAT satellite. We looked for evidence to support or reject the hypothesis that WR 11 is responsible of the gamma-ray excess. Archive radio interferometric data at 1.4 and 2.5 GHz taken with the Australia Telescope Compact Array along sixteen different dates were reduced. The sizes of the field-of-view at 2.5 GHz and of the central region of the Fermi LAT excess are alike. We analyzed the emission of the field of WR 11, characterized the radio sources detected and derived their spectral indices, to investigate their nature. Eight sources with fluxes above 10 mJy were detected at both frequencies. All but one (WR 11) showed negative spectral indices. Four of them were identified with known objects, including WR 11. A fifth source, labeled here S6, could be a promising candidate to produce gamma-ray emission, besides the CWB WR 11.
The colliding-wind region in binary systems made of massive stars allows us
to investigate various aspects of shock physics, including particle
acceleration. Particle accelerators of this kind are ...tagged as
Particle-Accelerating Colliding-Wind Binaries, and are mainly identified thanks
to their synchrotron radio emission. Our objective is first to validate the
idea that obtaining snapshot high-resolution radio images of massive binaries
constitutes a relevant approach to unambiguously identify particle
accelerators. Second, we intend to exploit these images to characterize the
synchrotron emission of two specific targets, HD167971 and HD168112, known as
particle accelerators. We traced the radio emission from the two targets at 1.6
GHz with the European Very Long Baseline Interferometry Network, with an
angular resolution of a few milli-arcseconds. Our measurements allowed us to
obtain images for both targets. For HD167971, our observation occurs close to
apastron, at an orbital phase where the synchrotron emission is minimum. For
HD168112, we resolved for the very first time the synchrotron emission region.
The emission region appears slightly elongated, in agreement with expectation
for a colliding-wind region. In both cases the measured emission is
significantly stronger than the expected thermal emission from the stellar
winds, lending strong support for a non-thermal nature. Our study brings a
significant contribution to the still poorly addressed question of high angular
resolution radio imaging of colliding-wind binaries. We show that snapshot Very
Long Baseline Interferometry measurements constitute an efficient approach to
investigate these objects, with promising results in terms of identification of
additional particle accelerators, on top of being promising as well to reveal
long period binaries.
The direct EPR detection of thioacyl radicals has been reported only once, while thioacyl nitroxides remain an elusive species. We failed to detect the thioacyl radicals from two thioaldehydes and ...from phosphoryldithioformates but have obtained EPR evidence that thioacyl radicals react with 2-methyl-2-nitrosopropane to give thiocarbonyloxyaminyls rather than thioacyl nitroxides. The results of DFT calculations support this unexpected reactivity of thioacyls, while making questionable their previous EPR identification.
The radicals formed upon visible light irradiation of the photoinitiator 2-benzyl-2-dimethylamino-4'-morpholinobutyrophenone (Irgacure 369), 1, were investigated by means of EPR spectroscopy coupled ...with the spin trapping technique both in the absence and in the presence of a monomer. The results suggest a dual behavior of 1 that may act both as a Type I and a Type II photoinitiator. From experiments carried out in the presence of 2-ethoxythioxanthone (Pila 124), 2, an additive commonly used in combination with 1 as sensitizer, it is inferred that 2 mainly acts via hydrogen abstraction from 1.
Corps et matière Benaglia, Cecilia; Bertina, Arno; Bertrand, Michel ...
Association des lecteurs de Claude Simon,
12/2017
Journal Article
Recenzirano
Odprti dostop
Une conscience historique habite l’œuvre de Claude Simon et, plus généralement, les écrivains du Nouveau Roman. Ainsi Simon déclarait-il en 1989 à Marianne Alphant : « Les choses. Si le surréalisme ...est né de la guerre de 1914, ce qui s’est passé après la dernière guerre est lié à Auschwitz. Il me semble qu’on l’oublie souvent quand on parle du “nouveau roman”. Ce n’est pas pour rien que Nathalie Sarraute a écrit L’Ère du soupçon ; Barthes, Le Degré zéro de l’écriture. Que des artistes comme Tàpies ou Dubuffet sont partis des graffitis, du mur, ou que Louise Nevelson a fait des sculptures à partir de décombres. Toutes les idéologies s’étaient disqualifiées. L’humanisme, c’était fini … : il n’y a plus de recours, essayons de revenir au primordial, à l’élémentaire, à la matière, aux choses. » Cette livraison des Cahiers entend montrer comment l’œuvre de Simon est marquée par ce retour à l’élémentaire. Elle s’ouvre par la reprise d’un texte court de Simon de 1961 (« Sous le kimono ») et d’un entretien long et rare publié en 1977 dans La Nouvelle critique. Le dossier critique se compose de sept études, dont deux articles anciens de critiques anglo-saxons qui ont fait date (dont l’un traduit pour la première fois), tous centrés sur la question du corps et de la matière. On trouve ensuite les rubriques traditionnelles des Cahiers : un bilan de la réception de Simon à l’étranger (le monde anglo-saxon), les paroles d’écrivains lecteurs de Simon (Arno Bertina et Oliver Rohe), les comptes rendus d’ouvrage et l’actualité de l’œuvre.
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