36 research outputs found
Evidences of spin-temperature in Dynamic Nuclear Polarization: an exact computation of the EPR spectrum
In dynamic nuclear polarization (DNP) experiments, the compound is driven
out-of-equilibrium by microwave (MW) irradiation of the radical electron spins.
Their stationary state has been recently probed via electron double resonance
(ELDOR) techniques showing, at low temperature, a broad depolarization of the
electron paramagnetic resonance (EPR) spectrum under microwave irradiation. In
this theoretical manuscript, we develop a numerical method to compute exactly
the EPR spectrum in presence of dipolar interactions. Our results reproduce the
observed broad depolarisation and provide a microscopic justification for
spectral diffusion mechanism. We show the validity of the spin-temperature
approach for typical radical concentration used in dissolution DNP protocols.
In particular once the interactions are properly taken into account, the
spin-temperature is consistent with the non-monotonic behavior of the EPR
spectrum with a wide minimum around the irradiated frequency.Comment: 8 pages, 7 figures. Title and abstract change
Picking out a wine: Consumer motivation behind different quality wines choice
The quality scale of Italian wines is mainly organized in four categories: PDO, PGI, basic and bulk wine. Our analysis explicitly investigates the patterns and determinants of consumption for these four different types of wine by analyzing a representative sample of consumers from a traditional wine-producing country. This study provides for first time insights on quality perceptions of wines and verifies whether Italian consumers perceive significant differences among the different categories of wines. The overall results, obtained through a system of equation estimates, show that consumer motivations and wine consumption determinants change according to each different range of wine quality and thereby support a hierarchical scale of quality wines, as a fact consumers' motivation progressively changes as the quality scales of the wine increase or decrease. In addition, this study highlights for first time any differences in the consumption determinants between the PDO and the PGI wines in a national context and it suggests that the influence of the two different GI labels on the wine choice of consumers is truly different. Important insights were also provided for bulk wine whose consumption seems to be closely related to wine tourism and the desire to buy locally produced wines. Keywords: Basic wines, Bulk wines, Local wines, PDO, PG
Spin fluctuations in the light-induced high spin state of Cobalt valence tautomers
We present a study of the static magnetic properties and spin dynamics in
Cobalt valence tautomers (VT), molecules where a low-spin (LS) to high-spin
(HS) crossover driven by an intramolecular electron transfer can be controlled
by the temperature, by the external pressure or by light irradiation. In the
investigated complex, a LS-Co(III) ion bound to a dinegative organic ligand can
be reversibly converted into the HS-Co(II) bound to a mononegative one. By
combining magnetization measurements with Nuclear Magnetic Resonance (NMR) and
Muon Spin Relaxation ({\mu}SR), we have investigated the static magnetic
properties and the spin dynamics as a function of the temperature. Moreover,
the effect of the external pressure as well as of the infrared light
irradiation have been explored through magnetometry and NMR measurements to
determine the spin dynamics of the HS state. The photoinduced HS state, which
can have a lifetime of several hours below 30 K, is characterized by spin
dynamics in the MHz range, which persist at least down to 10 K. The application
of an external pressure causes a progressive increase of the LS-HS crossover,
which reaches room temperature for pressures around 10 kbar
Tumor-derived microvesicles modulate antigen cross-processing via reactive oxygen species-mediated alkalinization of phagosomal compartment in dendritic cells
Dendritic cells (DCs) are the only antigen-presenting cells able to prime naïve T cells and
cross-prime antigen-specific CD8+ T cells. Their functionality is a requirement for the
induction and maintenance of long-lasting cancer immunity. Albeit intensively investigated,
the in vivo mechanisms underlying efficient antigen cross-processing and presentation
are not fully understood. Several pieces of evidence indicate that antigen transfer to DCs
mediated by microvesicles (MVs) enhances antigen immunogenicity. This mechanism
is also relevant for cross-presentation of those tumor-associated glycoproteins such as
MUC1 that are blocked in HLA class II compartment when internalized by DCs as soluble
molecules. Here, we present pieces of evidence that the internalization of tumor-derived
MVs modulates antigen-processing machinery of DCs. Employing MVs derived from
ovarian cancer ascites fluid and established tumor cell lines, we show that MV uptake
modifies DC phagosomal microenvironment, triggering reactive oxygen species (ROS)
accumulation and early alkalinization. Indeed, tumor MVs carry radical species and the
MV uptake by DCs counteracts the chemically mediated acidification of the phagosomal
compartment. Further pieces of evidence suggest that efficacious antigen cross-priming
of the MUC1 antigen carried by the tumor MVs results from the early signaling induced by
MV internalization and the function of the antigen-processing machinery of DCs. These
results strongly support the hypothesis that tumor-derived MVs impact antigen immunogenicity
by tuning the antigen-processing machinery of DCs, besides being carrier of
tumor antigens. Furthermore, these findings have important implications for the exploitation
of MVs as antigenic cell-free immunogen for DC-based therapeutic strategies
High incidence of infections in HIV-positive patients treated for lymphoproliferative disorders
Active and capable fault? The case study of Prata D'Ansidonia (L'Aquila, Central Apennine)
The study deals with the morphogenetic meaning of several linear
scarps that carved the paleo-landsurface of Valle Daria, an extended
geomorphological feature located between Barisciano (AQ) and Prata
D'Ansidonia (AQ). These villages are situated in the southern termination
of the L'Aquila intermontane basin (one of the largest basin of the central
Apennines), nearby the epicentral area of the 6th April 2009 earthquake
(Mw 6.1). These scarps, up to 3 meters high and up to 1.5 km long, define
narrow/elongated flat-bottom depressions, filled by colluvial deposits.
These depressions are carved into fluvial-deltaical conglomerates, dated
back to the lower Pleistocene. Even if different authors have interpreted
these shapes as a paleodrainage or secondary faults, a morphometrical study
of the Valle Daria paleo-landsurface provided several information which
cast doubt on these two interpretations. In order to better understand the
nature and the state of activity of these lineaments, geological,
geomorphological and geophysical surveys were carried out. A
paleoseismological trench pointed out two events of deformation. The
curvilinear shape of the shear plane seems to be related to a slow
deformation, attributable to collapse-phenomena. Three GPR profiles, two
ERT profiles and two microgravimetrical profiles seem to corroborate this
interpretation. Therefore, this study permits to attribute the genesis of these
scarps to tectono-karstic phenomena, excluding the presence of an active
and capable fault.Published346-3494T. Sismologia, geofisica e geologia per l'ingegneria sismicaN/A or not JC
Patente a punti e sicurezza stradale: effetti e comparazioni
Printed from http://www.aci.it target=NewWindow>www.aci.it (July 2004)Consiglio Nazionale delle Ricerche - Biblioteca Centrale - P.le Aldo Moro, 7 , Rome / CNR - Consiglio Nazionale delle RichercheSIGLEITItal