Search results for "junctions"

Superconducting spintronic tunnel diode

2022

Diodes are key elements for electronics, optics, and detection. Their evolution towards low dissipation electronics has seen the hybridization with superconductors and the realization of supercurrent diodes with zero resistance in only one direction. Here, we present the quasi-particle counterpart, a superconducting tunnel diode with zero conductance in only one direction. The direction-selective propagation of the charge has been obtained through the broken electron-hole symmetry induced by the spin selection of the ferromagnetic tunnel barrier: a EuS thin film separating a superconducting Al and a normal metal Cu layer. The Cu/EuS/Al tunnel junction achieves a large rectification (up to ∼…

Fabrication, Electrical Characterization and 1/f Noise Study of Submicron-sized Superconducting Tunnel Junctions

2016

Mechanisms of C-reactive protein-induced blood-brain barrier disruption.

2009

Background and Purpose— Increased mortality after stroke is associated with brain edema formation and high plasma levels of the acute phase reactant C-reactive protein (CRP). The aim of this study was to examine whether CRP directly affects blood–brain barrier stability and to analyze the underlying signaling pathways. Methods— We used a cell coculture model of the blood–brain barrier and the guinea pig isolated whole brain preparation. Results— We could show that CRP at clinically relevant concentrations (10 to 20 μg/mL) causes a disruption of the blood–brain barrier in both approaches. The results of our study further demonstrate CRP-induced activation of surface Fcγ receptors CD16/32 fo…

Increased Connexin 43 Expression as a Potential Mediator of the Neuroprotective Activity of the Corticotropin-Releasing Hormone

2009

CRH is a major central stress mediator, but also a potent neuroprotective effector. The mechanisms by which CRH mediates its neuroprotective actions are largely unknown. Here, we describe that the gap junction molecule connexin43 (Cx43) mediates neuroprotective effects of CRH toward experimentally induced oxidative stress. An enhanced gap junction communication has been reported to contribute to neuroprotection after neurotoxic insults. We show that CRH treatment up-regulates Cx43 expression and gap junctional communication in a CRH receptor-dependent manner in IMR32 neuroblastoma cells, primary astrocytes, and organotypic hippocampal slice cultures. MAPKs and protein kinase A-cAMP response…

Efficiency of concentration photovoltaic cells governed by luminescence processes

2013

The development of multi-junctions III-V semiconductors solar cells, that combine high conversion efficiency (over 40%) and capability of working under high illumination intensity (up to 1000 suns), has stimulated a rapid growth of concentrating photovoltaic (CPV) technology. The performance of these cells is based on the matching between the semiconductors band gap and the solar spectrum so as to optimize the current balancing between the subcells. This requirement is also important in connection with the CPV modules using lenses, mirrors, optical coupling compounds that introduce a wavelength dependent response to the sunlight. Therefore, care must be exercised in designing optimum cells …

Time-dependent Landauer—Büttiker formalism for superconducting junctions at arbitrary temperatures

2016

We discuss an extension of our earlier work on the time-dependent Landauer– Büttiker formalism for noninteracting electronic transport. The formalism can without complication be extended to superconducting central regions since the Green’s functions in the Nambu representation satisfy the same equations of motion which, in turn, leads to the same closed expression for the equal-time lesser Green’s function, i.e., for the time-dependent reduced one-particle density matrix. We further write the finite-temperature frequency integrals in terms of known special functions thereby considerably speeding up the computation. Simulations in simple normal metal – superconductor – normal metal junctions…

ORGANOTIN(IV)-PORPHINATE FOR PHOTOVOLTAIC BULK HETEROJUNCTIONS

2013

Due to the versatility and variability of their molecular structures, optical spectra, electrical properties, and supramolecular organization potential, porphyrins related compounds have been widely studied in organic solar cells [1,2]. Indeed, these applications are a natural function for these compounds, and they have been extensively investigated in a variety of formats including single molecules, macromolecular and supramolecular structures. In this work, poly(hexylthiophene) (P3HT) and organotin(IV)-[meso-tetra(4-carboxyphenyl) porphinate] have been employed for engineering planar and bulk heterojunctions by layer by layer deposition. Improving the overall efficiencies of photovoltaic …

CONTROLLING THE QUANTUM DYNAMICS OF MULTIPARTITE JOSEPHSON CIRCUITS

2011

CONTROLLING THE QUANTUM DYNAMICS OF MULTIPARTITE JOSEPHSON CIRCUITS

Fabrication of 3-D phononic crystals for thermal transport management

2016

Thermal transport is an important physical phenomenon, and it has recently become even more relevant for the reduction of energy losses and the increase of efficiency in novel devices based on thermoelectricity [1]. Significant reduction of thermal conduction was recently achieved by coherent modification of phonon modes [2], with the help of periodic phononic crystal structures. However, currently the experimental studies have only been performed for two-dimensional (2-D) nanostructures. Theoretically, the magnitude of control of thermal transport should be even stronger in three-dimensional (3-D) phononic crystal structures. For that reason, the question arises how to fabricate the desire…

Universal Restrictions in Reading: What Do French Beginning Readers (Mis)perceive?

2020

International audience; Despite the many reports that consider statistical distribution to be vitally important in visual identification tasks in children, some recent studies suggest that children do not always rely on statistical properties to help them locate syllable boundaries. Indeed, sonority-a universal phonological element-might be a reliable source for syllable segmentation. More specifically, are children sensitive to a universal phonological sonority-based markedness continuum within the syllable boundaries for segmentation (e.g., from marked, illegal intervocalic clusters, "jr," to unmarked, legal intervocalic clusters, "rj"), and how does this sensitivity progress with reading…