Search results for "BLOCKADE"
showing 10 items of 164 documents
Influence of AT-1 receptor blockade on endothelium - derived factors in essential hypertension.
1999
C-X-C Motif Chemokine Receptor 4 Blockade Promotes Tissue Repair After Myocardial Infarction by Enhancing Regulatory T Cell Mobilization and Immune-R…
2019
Background: Acute myocardial infarction (MI) elicits an inflammatory response that drives tissue repair and adverse cardiac remodeling. Inflammatory cell trafficking after MI is controlled by C-X-C motif chemokine ligand 12 (CXCL12) and its receptor, C-X-C motif chemokine receptor 4 (CXCR4). CXCR4 antagonists mobilize inflammatory cells and promote infarct repair, but the cellular mechanisms are unclear. Methods: We investigated the therapeutic potential and mode of action of the peptidic macrocycle CXCR4 antagonist POL5551 in mice with reperfused MI. We applied cell depletion and adoptive transfer strategies using lymphocyte-deficient Rag1 knockout mice; DEREG mice, which express a diphth…
Coulomb blockade thermometer: Tests and instrumentation
1998
Coulomb blockade thermometry (CBT) provides a simple method for absolute thermometry in every day laboratory use at cryogenic temperatures. CBT has been found insensitive to even high magnetic fields. We review the principles and the operation of CBT and the fabrication of the sensors, and present new data on radiation hardness and stability of the sensors. We describe the instrumentation of CBT in detail. We have developed two signal conditioning units for CBT measurements. One is a modified alternating current resistance bridge, a versatile laboratory instrument operating with a PC computer, and the other one is a simple stand-alone instrument for direct temperature reading. Test results …
Logic gates scheme based on Coulomb blockade in metallic nanoclusters with organic ligands
2010
We propose a logic gates scheme based on the electron transfer through metallic nanoclusters linked to organic ligands and discuss theoretically the characteristics needed for practical implementation. As a proof-of-the-concept, we demonstrate the OR, AND and NOT gates and study the performance in terms of temperature, applied voltage, and noise.
Reliable signal processing using parallel arrays of non-identical nanostructures and stochastic resonance
2010
In the stochastic resonance (SR) phenomena, the response of a non-linear system to a weak periodic input signal is optimised by the presence of a particular level of noise which enhances signal detection. We explore, theoretically, the influence of thermal noise in arrays of metal nanoparticles functionalised with organic ligands acting as tunnelling junctions, with emphasis on the interplay between the SR phenomena and the nanostructure variability. In this system, the transference of a reduced number of electrons may suffice to implement a variety of electronic functions. However, because nanostructures are expected to show a significant variability in their physical characteristics, it i…
Sub-threshold signal processing in arrays of non-identical nanostructures
2011
Weak input signals are routinely processed by molecular-scaled biological networks composed of non-identical units that operate correctly in a noisy environment. In order to show that artificial nanostructures can mimic this behavior, we explore theoretically noise-assisted signal processing in arrays of metallic nanoparticles functionalized with organic ligands that act as tunneling junctions connecting the nanoparticle to the external electrodes. The electronic transfer through the nanostructure is based on the Coulomb blockade and tunneling effects. Because of the fabrication uncertainties, these nanostructures are expected to show a high variability in their physical characteristics and…
Method for finding the critical temperature of the island in a SET structure
2008
We present a method to measure the critical temperature of the island of a superconducting single electron transistor. The method is based on a sharp change in the slope of the zero-bias conductance as a function of temperature. We have used this method to determine the superconducting phase transition temperature of the Nb island of an superconducting single electron transistor with Al leads. We obtain $T_\mathrm{c}^\mathrm{Nb}$ as high as 8.5 K and gap energies up to $\Delta_\mathrm{Nb}\simeq 1.45$ meV. By looking at the zero bias conductance as a function of magnetic field instead of temperature, also the critical field of the island can be determined. Using the orthodox theory, we have …
Characterisation of Cooper pair boxes for quantum computing
2001
We have measured and characterised superconducting single Cooper pair boxes (SCB) using superconducting single electron transistor (SET) fabricated on the same chip as an electrometer. The electrometer is sensitive to the potential changes of the SCB island and thus measures the number of excess Cooper pairs on the island. The boxes were of the Al/AlOx/Al Josephson junction type. The SCB and SET were characterised separately and the box storage performance for Cooper pairs was analysed by observing the changes in the SCB island potential while sweeping the gate voltage.
Coulomb Blockade and Bloch Oscillations in Superconducting Ti Nanowires
2012
Quantum fluctuations in quasi-one-dimensional superconducting channels leading to spontaneous changes of the phase of the order parameter by $2\pi$, alternatively called quantum phase slips (QPS), manifest themselves as the finite resistance well below the critical temperature of thin superconducting nanowires and the suppression of persistent currents in tiny superconducting nanorings. Here we report the experimental evidence that in a current-biased superconducting nanowire the same QPS process is responsible for the insulating state -- the Coulomb blockade. When exposed to RF radiation, the internal Bloch oscillations can be synchronized with the external RF drive leading to formation of…
Proximity-induced Josephson-quasiparticle process in a single-electron transistor
1998
We have performed the first experiments in a superconductor - normal metal - superconductor single electron transistor in which there is an extra superconducting strip partially overlapping the normal metal island in good metal-to-metal contact. Superconducting proximity effect gives rise to current peaks at voltages below the quasiparticle threshold. We interpret these peaks in terms of the Josephson-quasiparticle process and discuss their connection with the proximity induced energy gap in the normal metal island.