23 research outputs found
Electrochromism in Electrolyte-Free and Solution Processed Bragg Stacks
Achieving an active manipulation of colours has huge implications in
optoelectronics, as colours engineering can be exploited in a number of
applications, ranging from display to lightning. In the last decade, the
synergy of the highly pure colours of 1D photonic crystals, also known as Bragg
stacks, with electro-tunable materials have been proposed as an interesting
route to attain such a technologically relevant effect. However, recent works
rely on the use of liquid electrolytes, which can pose issues in terms of
chemical and environmental stability. Here, we report on the proof-of-concept
of an electrolyte free and solution-processed electrochromic Bragg stack. We
integrate an electro-responsive plasmonic metal oxide, namely indium tin oxide,
in a 1D photonic crystal structure made of alternating layers of ITO and TiO2
nanoparticles. In such a device we observed 15 nm blue-shift upon application
of an external bias (5 V), an effect that we attribute to the increase of ITO
charge density arising from the capacitive charging at the metal
oxide/dielectric interface and from the current flowing throughout the porous
structure. Our data suggest that electrochromism can be attained in all-solid
state systems by combining a judicious selection of the constituent materials
with device architecture optimisation
Analisi econometrica degli effetti del protezionismo comunitario sulla domanda di importazione di alcuni prodotti agricoli in Italia
5-Hydroxytryptamine Modulates Maturation and Mitochondria Function of Human Oligodendrocyte Progenitor M03-13 Cells
Inside the adult CNS, oligodendrocyte progenitor cells (OPCS) are able to proliferate, migrate and differentiate into mature oligodendrocytes (OLs) which are responsible for the production of myelin sheet and energy supply for neurons. Moreover, in demyelinating diseases, OPCs are recruited to the lesion areas where they undergo differentiation and myelin synthesis. Serotonin (5-hydroxytryptamine, 5-HT) is involved in OLs’ development and myelination, but so far the molecular mechanisms involved or the effects of 5-HT on mitochondria function have not yet been well documented. Our data show that 5-HT inhibits migration and proliferation committing cells toward differentiation in an immortalized human oligodendrocyte precursor cell line, M03-13. Migration blockage is mediated by reactive oxygen species (ROS) generation since antioxidants, such as Vit C and Cu-Zn superoxide dismutase, prevent the inhibitory effects of 5-HT on cell migration. 5-HT inhibits OPC migration and proliferation and increases OL phenotypic markers myelin basic protein (MBP) and Olig-2 via protein kinase C (PKC) activation since the inhibitor of PKC, bis-indolyl-maleimide (BIM), counteracts 5-HT effects. NOX inhibitors as well, reverse the effects of 5-HT, indicating that 5-HT influences the maturation process of OPCs by NOX-dependent ROS production. Finally, 5-HT increases mitochondria function and antioxidant activity. The identification of the molecular mechanisms underlying the effects of 5-HT on maturation and energy metabolism of OPCs could pave the way for the development of new treatments for autoimmune demyelinating diseases such as Multiple Sclerosis where oligodendrocytes are the primary target of immune attack
A Characterization System for the Monitoring of ELI-NP Gamma Beam
The ELI-NP (Extreme Light Infrastructure-Nuclear Physics) facility, currently under
construction near Bucharest (Romania), is the pillar of the project ELI dedicated to the generation of
high-brilliance gamma beams and high-power laser pulses that will be used for frontier research in
nuclear physics. To develop an experimental program at the frontiers of the present-day knowledge,
two pieces of equipment will be deployed at ELI-NP: a high power laser system consisting of two
10 PW lasers and a high brilliance gamma beam system. The ELI-NP Gamma beam system will
deliver an intense gamma beam with unprecedented specifications in terms of photon flux, brilliance
and energy bandwidth in an energy range from 0.2 to 20 MeV. Such a gamma beam requires special
devices and techniques to measure and monitor the beam parameters during the commissioning and
the operational phase. To accomplish this task, the Gamma Beam Characterization System, equipped
with four elements, was developed: a Compton spectrometer (CSPEC), to measure and monitor the
photon energy spectrum; a nuclear resonant scattering system (NRSS), for absolute beam energy
calibration and inter-calibration of the other detectors; a beam profile imager (GPI) to be used for
alignment and diagnostics purposes; and finally a sampling calorimeter (GCAL), for a fast combined
measurement of the beam average energy and intensity. The combination of the measurements
performed by GCAL and CSPEC allows fully characterizing the gamma beam energy distribution
and intensity with a precision at the level of few per mill, enough to demonstrate the fulfillment
of the required parameters. This article presents an overview of the gamma beam characterization
system with focus on these two detectors, which were designed, assembled and are currently under
test at INFN-Firenze. The layout and the working principle of the four devices is described, as well
as some of the main results of detector test
Reactive oxygen species regulate the levels of dual oxidase (Duox1-2) in human neuroblastoma cells.
Dual Oxidases (DUOX) 1 and 2 are efficiently expressed in thyroid, gut, lung and immune system. The function and the regulation of these enzymes in mammals are still largely unknown. We report here that DUOX 1 and 2 are expressed in human neuroblastoma SK-N-BE cells as well as in a human oligodendrocyte cell line (MO3-13) and in rat brain and they are induced by platelet derived growth factor (PDGF). The levels of DUOX 1 and 2 proteins and mRNAs are induced by reactive oxygen species (ROS) produced by the membrane NADPH oxidase. As to the mechanism, we find that PDGF stimulates membrane NADPH oxidase to produce ROS, which stabilize DUOX1 and 2 mRNAs and increases the levels of the proteins. Silencing of gp91(phox) (NOX2), or of the other membrane subunit of NADPH oxidase, p22(phox), blocks PDGF induction of DUOX1 and 2. These data unravel a novel mechanism of regulation of DUOX enzymes by ROS and identify a circuitry linking NADPH oxidase activity to DUOX1 and 2 levels in neuroblastoma cells.Journal ArticleResearch Support, Non-U.S. Gov'tSCOPUS: ar.jinfo:eu-repo/semantics/publishe