757 research outputs found
Temperature inversion symmetry in the Casimir effect with an antiperiodic boundary condition
We present explicitly another example of a temperature inversion symmetry in
the Casimir effect for a nonsymmetric boundary condition. We also give an
interpretation for our result.Comment: 4 page
Pathogenesis of hypertension in a mouse model for human CLCN2 related hyperaldosteronism
Human primary aldosteronism (PA) can be caused by mutations in several ion channel genes but mouse models replicating this condition are lacking. We now show that almost all known PA-associated CLCN2 mutations markedly increase ClC-2 chloride currents and generate knock-in mice expressing a constitutively open ClC-2 Cl(−) channel as mouse model for PA. The Clcn2(op) allele strongly increases the chloride conductance of zona glomerulosa cells, provoking a strong depolarization and increasing cytoplasmic Ca(2+) concentration. Clcn2(op) mice display typical features of human PA, including high serum aldosterone in the presence of low renin activity, marked hypertension and hypokalemia. These symptoms are more pronounced in homozygous Clcn2(op/op) than in heterozygous Clcn2+/op mice. This difference is attributed to the unexpected finding that only ~50 % of Clcn2(+/op) zona glomerulosa cells are depolarized. By reproducing essential features of human PA, Clcn2(op) mice are a valuable model to study the pathological mechanisms underlying this disease
Cytochrome c speeds up caspase cascade activation by blocking 14-3-3¿-dependent Apaf-1 inhibition article
Apoptosis is a highly regulated form of programmed cell death, essential to the development and homeostasis of multicellular organisms. Cytochrome c is a central figure in the activation of the apoptotic intrinsic pathway, thereby activating the caspase cascade through its interaction with Apaf-1. Our recent studies have revealed 14-3-3€ (a direct inhibitor of Apaf-1) as a cytosolic cytochrome c target. Here we explore the cytochrome c / 14-3-3€ interaction and show the ability of cytochrome c to block 14-3-3€-mediated Apaf-1 inhibition, thereby unveiling a novel function for cytochrome c as an indirect activator of caspase-9/3. We have used calorimetry, NMR spectroscopy, site mutagenesis and computational calculations to provide an insight into the structural features of the cytochrome c / 14-3-3€ complex. Overall, these findings suggest an additional cytochrome c-mediated mechanism to modulate apoptosome formation, shedding light onto the rigorous apoptotic regulation network
The electronic structure of metal/alkane thiol self-assembled monolayers/metal junctions for magnetoelectronics applications
Long-chain alkane thiols use in metal to organic self-assembled monolayer to metal junctions may be limited by orientational disorder, and photoemission studies suggest that several molecular layers may be needed for the dielectric layer to be effective. Several alkane thiols were investigated in a range of junctions areas 10–102 μm2. Top layer contact deposition, activated with Pd clusters resulted in a high yield of junctions that were not electrically shorted and are stable over a wide temperature range. Zerobias anomalies, observed at low temperatures, are attributed to a Coulomb blockade associated with the Pd clusters
Nonextensivity and Galaxy Clustering in the Universe
We investigate two important questions about the use of the nonextensive
thermostatistics (NETS) formalism in the context of nonlinear galaxy clustering
in the Universe. Firstly, we define a quantitative criterion for justifying
nonextensivity at different physical scales. Then, we discuss the physics
behind the ansatz of the entropic parameter . Our results suggest the
approximate range where nonextensivity can be justified and, hence, give some
support to the applicability of NETS to the study of large scale structures.Comment: 8 pages, written version of a talk presented in the International
Workshop on Trends and Perspectives on Extensive and Non-Extensive
Statistical Mechanics. Accepted for publication in Physica
Biophotonic Sensing Cells (BICELLs) for label-free biosensing
Label free immunoassay sector is a ferment of activity, experiencing rapid growth as new technologies come forward and achieve acceptance. The landscape is changing in a “bottom up” approach, as individual companies promote individual technologies and find a market for them. Therefore, each of the companies operating in the label-free immunoassay sector offers a technology that is in some way unique and proprietary. However, no many technologies based on Label-free technology are currently in the market for PoC and High Throughput Screening (HTS), where mature labeled technologies have taken the market
Low temperature transport in AC-driven Quantum Dots in the Kondo regime
We present a fully nonequilibrium calculation of the low temperature
transport properties of a quantum dot in the Kondo regime when an AC potential
is applied to the gate voltage. We solve a time dependent Anderson model with
finite on-site Coulomb interaction. The interaction self-energy is calculated
up to second order in perturbation theory in the on-site interaction, in the
context of the Keldysh non-equilibrium technique, and the effect of the AC
voltage is taken into account exactly for all ranges of AC frequencies and AC
intensities. The obtained linear conductance and time-averaged density of
states of the quantum dot evolve in a non trivial way as a function of the AC
frequency and AC intensity of the harmonic modulation.Comment: 30 pages,7 figure
Using metabarcoding to assess Viridiplantae sequence diversity present in Antarctic glacial ice
Antarctica contains most of the glacial ice on the planet, a habitat that is largely unexplored by biologists. Recent warming in parts of Antarctica, particularly the Antarctic Peninsula region, is leading to widespread glacial retreat, releasing melt water and, potentially, contained biological material and propagules. In this study, we used a DNA metabarcoding approach to characterize Viridiplantae DNA present in Antarctic glacial ice. Ice samples from six glaciers in the South Shetland Islands and Antarctic Peninsula were analysed, detecting the presence of DNA representing a total of 16 taxa including 11 Chlorophyta (green algae) and five Magnoliophyta (flowering plants). The green algae may indicate the presence of a viable algal community in the ice or simply of preserved DNA, and the sequence diversity assigned included representatives of Chlorophyta not previously recorded in Antarctica. The presence of flowering plant DNA is most likely to be associated with pollen or tissue fragments introduced by humans
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