1,987 research outputs found
Rapid degradation of mutant SLC25A46 by the ubiquitin-proteasome system results in MFN1/2-mediated hyperfusion of mitochondria.
SCL25A46 is a mitochondrial carrier protein that surprisingly localizes to the outer membrane and is distantly related to Ugo1. Here we show that a subset of SLC25A46 interacts with mitochondrial dynamics components and the MICOS complex. Decreased expression of SLC25A46 results in increased stability and oligomerization of MFN1 and MFN2 on mitochondria, promoting mitochondrial hyperfusion. A mutation at L341P causes rapid degradation of SLC25A46, which manifests as a rare disease, pontocerebellar hypoplasia. The E3 ubiquitin ligases MULAN and MARCH5 coordinate ubiquitylation of SLC25A46 L341P, leading to degradation by organized activities of P97 and the proteasome. Whereas outer mitochondrial membrane-associated degradation is typically associated with apoptosis or a specialized type of autophagy termed mitophagy, SLC25A46 degradation operates independently of activation of outer membrane stress pathways. Thus SLC25A46 is a new component in mitochondrial dynamics that serves as a regulator for MFN1/2 oligomerization. Moreover, SLC25A46 is selectively degraded from the outer membrane independently of mitophagy and apoptosis, providing a framework for mechanistic studies in the proteolysis of outer membrane proteins
Experimental study of electric breakdowns in liquid argon at centimeter scale
In this paper we present results on measurements of the dielectric strength
of liquid argon near its boiling point and cathode-anode distances in the range
of 0.1 mm to 40 mm with spherical cathode and plane anode. We show that at such
distances the applied electric field at which breakdowns occur is as low as 40
kV/cm. Flash-overs across the ribbed dielectric of the high voltage
feed-through are observed for a length of 300 mm starting from a voltage of 55
kV. These results contribute to set reference for the breakdown-free design of
ionization detectors, such as Liquid Argon Time Projection Chambers (LAr TPC)
On the Electric Breakdown in Liquid Argon at Centimeter Scale
We present a study on the dependence of electric breakdown discharge
properties on electrode geometry and the breakdown field in liquid argon near
its boiling point. The measurements were performed with a spherical cathode and
a planar anode at distances ranging from 0.1 mm to 10.0 mm. A detailed study of
the time evolution of the breakdown volt-ampere characteristics was performed
for the first time. It revealed a slow streamer development phase in the
discharge. The results of a spectroscopic study of the visible light emission
of the breakdowns complement the measurements. The light emission from the
initial phase of the discharge is attributed to electro-luminescence of liquid
argon following a current of drifting electrons. These results contribute to
set benchmarks for breakdown-safe design of ionization detectors, such as
Liquid Argon Time Projection Chambers (LAr TPC).Comment: Minor revision according to editor report. 17 pages, 15 figures, 2
tables. Turboencabulato
A method to suppress dielectric breakdowns in liquid argon ionization detectors for cathode to ground distances of several millimeters
We present a method to reach electric field intensity as high as 400 kV/cm in
liquid argon for cathode-ground distances of several millimeters. This can be
achieved by suppressing field emission from the cathode, overcoming limitations
that we reported earlier
Measurement of the drift field in the ARGONTUBE LAr TPC with 266~nm pulsed laser beams
ARGONTUBE is a liquid argon time projection chamber (LAr TPC) with a drift
field generated in-situ by a Greinacher voltage multiplier circuit. We present
results on the measurement of the drift-field distribution inside ARGONTUBE
using straight ionization tracks generated by an intense UV laser beam. Our
analysis is based on a simplified model of the charging of a multi-stage
Greinacher circuit to describe the voltages on the field cage rings
GeneXplorer: an interactive web application for microarray data visualization and analysis
BACKGROUND: When publishing large-scale microarray datasets, it is of great value to create supplemental websites where either the full data, or selected subsets corresponding to figures within the paper, can be browsed. We set out to create a CGI application containing many of the features of some of the existing standalone software for the visualization of clustered microarray data. RESULTS: We present GeneXplorer, a web application for interactive microarray data visualization and analysis in a web environment. GeneXplorer allows users to browse a microarray dataset in an intuitive fashion. It provides simple access to microarray data over the Internet and uses only HTML and JavaScript to display graphic and annotation information. It provides radar and zoom views of the data, allows display of the nearest neighbors to a gene expression vector based on their Pearson correlations and provides the ability to search gene annotation fields. CONCLUSIONS: The software is released under the permissive MIT Open Source license, and the complete documentation and the entire source code are freely available for download from CPAN
Phase Transition Study of Superconducting Microstructures
The presented results are part of a feasibility study of superheated
superconducting microstructure detectors. The microstructures (dots) were
fabricated using thin film patterning techniques with diameters ranging from
m up to m and thickness of m. We used arrays and single
dots to study the dynamics of the superheating and supercooling phase
transitions in a magnetic field parallel to the dot surface. The phase transi-
tions were produced by either varying the applied magnetic field strength at a
constant temperature or changing the bath temperature at a constant field.
Preliminary results on the dynamics of the phase transitions of arrays and
single indium dots will be reported.Comment: 7pages in LaTex format, five figures available upon request by
[email protected], preprint Bu-He 93/
Renormalization Group and Universality
It is argued that universality is severely limited for models with multiple
fixed points. As a demonstration the renormalization group equations are
presented for the potential and the wave function renormalization constants in
the scalar field theory. Our equations are superior compared with the
usual approach which retains only the contributions that are non-vanishing in
the ultraviolet regime. We find an indication for the existence of relevant
operators at the infrared fixed point, contrary to common expectations. This
result makes the sufficiency of using only renormalizable coupling constants in
parametrizing the long distance phenomena questionable.Comment: 32pp in plain tex; revised version to appear in PR
Quantum-classical crossover in electrodynamics
A classical field theory is proposed for the electric current and the
electromagnetic field interpolating between microscopic and macroscopic
domains. It represents a generalization of the density functional for the
dynamics of the current and the electromagnetic field in the quantum side of
the crossover and reproduces standard classical electrodynamics on the other
side. The effective action derived in the closed time path formalism and the
equations of motion follow from the variational principle. The polarization of
the Dirac-see can be taken into account in the quadratic approximation of the
action by the introduction of the deplacement field strengths as in
conventional classical electrodynamics. Decoherence appears naturally as a
simple one-loop effect in this formalism. It is argued that the radiation time
arrow is generated from the quantum boundary conditions in time by decoherence
at the quantum-classical crossover and the Abraham-Lorentz force arises from
the accelerating charge or from other charges in the macroscopic or the
microscopic side, respectively. The functional form of quantum renormalization
group, the generalization of the renormalization group method for the density
matrix, is proposed to follow the scale dependence through the
quantum-classical crossover in a systematical manner.Comment: new references added, few sign errors fixed, to appear in Physical
Review
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