Search results for " polar"
showing 10 items of 1091 documents
PSA-based phase regeneration of DPSK signals in a silicon germanium waveguide
2015
We demonstrate a polarization-assisted PSA-based phase regenerator in a passive low-birefringence SiGe waveguide at low CW pump power. A PSER of 28.6-dB enables a six-fold reduction in phase-error and BER improvement of approximately 2-dB in the regenerated signal.
Modification of the Selectivity Properties of Tubular Ceramic Membranes after Alkaline Treatment
2017
International audience; This work focuses on the selectivity modification of ceramic membranes after a mild alkaline treatment. Filtration of pure saltwater solutions was carried out with commercial titania membranes before and after the treatment. After treatment, the rejection of NaF significantly decreased, while the rejection of NaCl and NaBr increased. Additionally, NaI and Na 2 SO 4 remained close to zero. Pore size and electrical charge being almost unchanged, only significant modifications in the dielectric effects can explain this modification of selectivity. Therefore, the surface chemistry and the interaction (nature and magnitude) with the solvent and with the species present in…
The polarimetric and helioseismic imager on solar orbiter
2020
This paper describes the Polarimetric and Helioseismic Imager on the Solar Orbiter mission (SO/PHI), the first magnetograph and helioseismology instrument to observe the Sun from outside the Sun-Earth line. It is the key instrument meant to address the top-level science question: How does the solar dynamo work and drive connections between the Sun and the heliosphere? SO/PHI will also play an important role in answering the other top-level science questions of Solar Orbiter, as well as hosting the potential of a rich return in further science. SO/PHI measures the Zeeman effect and the Doppler shift in the FeI 617.3nm spectral line. To this end, the instrument carries out narrow-band imaging…
Density of States characterization of TiO2 films deposited by Pulsed Laser Deposition for Heterojunction solar cells
2021
The application of titanium dioxide (TiO2) in the photovoltaic field is gaining traction as this material can be deployed in doping-free heterojunction solar cells with the role of electron selective contact. For modeling-based optimization of such contact, knowledge of the titanium oxide defect density of states is crucial. In this paper, we report a method to extract the defect density through nondestructive optical measures, including the contribution given by small polaron optical transitions. The presence of both related to oxygen-vacancy defects and polarons is supported by the results of optical characterizations and the evaluation of previous observations resulting in a defect band …
Reversed-phase liquid chromatography with mixed micellar mobile phases of Brij-35 and sodium dodecyl sulphate: a method for the analysis of basic com…
2015
Micellar liquid chromatography (MLC) is a reversed-phase liquid chromatographic (RPLC) mode, which uses a surfactant as a modifier, with significant changes in retention and selectivity with regard to the classical RPLC mode that employs mixtures of water and organic solvent. The anionic sodium dodecyl sulphate (SDS) is the most usual surfactant in MLC, but it also requires the addition of an organic solvent to decrease the retention times and increase the efficiency. In particular, positively charged basic compounds are strongly retained by the stationary phase modified by adsorption of SDS monomers and require the addition of a strong solvent, such as propanol or pentanol. The non-ionic s…
Molecular aggregates of quinuclidine and chlorophyll a
1991
A slightly polar molecule quinuclidine seems to form weakly bound aggregates in concentrated water solutions. Molecular dynamics simulation of a 6 mol water solution indicates clustering of quinuclidine molecules into an almost spherical structure with polar ends of the molecules pointing towards the solvent. Experimental evidence of aggregation was obtained by observing a small but obvious red shift of the o'' a absorption and a dramatic shortening of the fluorescence lifetime of the c n transition of concentrated solutions. The observed self-quenching is interpreted in terms of Frster model for energy transfer in the cluster. It is estimated that excitation may migrate on the cluster surf…
Sorafenib perpetuates cellular anti-cancer effector functions by modulating the cross talk between macrophages and natural killer cells.
2012
Alternatively polarized macrophages (Mϕ) shape the microenvironment of hepatocellular carcinoma (HCC) and temper anticancer immune responses. We investigated if sorafenib alters the HCC microenvironment by restoring classical macrophage polarization and triggering tumor-directed natural killer (NK) cell responses. In vivo experiments were conducted with sorafenib (25 mg/kg)-treated C57BL/6 wildtype as well as hepatitis B virus (HBV) and lymphotoxin transgenic mice with and without HCC. Monocyte-derived Mϕ or tumor-associated macrophages (TAM) isolated from HCC tissue were treated with sorafenib (0.07-5.0 μg/mL) and cocultured with autologous NK cells. Mϕ and NK cell activation was analyzed …
Microphones’ Directivity for the Localization of Sound Sources
2011
In a recent paper [P. Rizzo, G. Bordoni, A. Marzani, and J. Vipperman, "Localization of Sound Sources by Means of Unidirectional Microphones, Meas. Sci. Tech., 20, 055202 (12pp), 2009] the proof-of-concept of an approach for the localization of acoustic sources was presented. The method relies on the use of unidirectional microphones and amplitude-based signals' features to extract information about the direction of the incoming sound. By intersecting the directions identified by a pair of microphones, the position of the emitting source can be identified. In this paper we expand the work presented previously by assessing the effectiveness of the approach for the localization of an acoustic…
Cloning and characterization of the promoter of Hugl-2, the human homologue of Drosophila lethal giant larvae (lgl) polarity gene.
2007
The human lgl gene, Hugl-2 (llgl2, Lgl2), codes for a cytoskeletal protein involved in regulating cell polarity. Here, we report the identification and functional characterization of the promoter region ( approximately 1.2kb) of the Hugl-2 gene. Luciferase expression assays show a high basal Hugl-2 promoter activity in different cell lines and primary human hepatocytes. Truncations of the promoter identified a GC-rich region important for this activity. Alignment of human and mouse genomic sequences demonstrate that this is an evolutionary conserved region fcontaining putative binding sites for several transcription factors including Elk-1 and Sp-1. Mithramycin A reduces Hugl-2 expression i…
Data repeatability and acquisition techniques for Time-Domain Spectral Induced Polarization
2013
The Time Domain Induced Polarization (TDIP) technique is widely used in applied geophysics, particularly for environmental issues, for instance for delineating landfills or detecting leachate percolation. Because the reliability of IP data remains an issue at the field scale, this paper deals with the factors controlling data quality and compares different arrays and acquisition parameters for optimal collection of data in the field. The first part focuses on repeatability experiments carried out in the former Horlokke landfill (Denmark), in order to infer the degree of which a signal can be reproduced over time. Results show a good repeatability, with on average less than 10% of difference…