6,862 research outputs found
A shared mechanism of muscle wasting in cancer and Huntington's disease.
Skeletal muscle loss and dysfunction in aging and chronic diseases is one of the major causes of mortality in patients, and is relevant for a wide variety of diseases such as neurodegeneration and cancer. Muscle loss is accompanied by changes in gene expression and metabolism that lead to contractile impairment and likely affect whole-body metabolism and function. The changes may be caused by inactivity, inflammation, age-related factors or unbalanced nutrition. Although links with skeletal muscle loss have been found in diseases with disparate aetiologies, for example both in Huntingtons disease (HD) and cancer cachexia, the outcome is a similar impairment and mortality. This short commentary aims to summarize recent achievements in the identification of common mechanisms leading to the skeletal muscle wasting syndrome seen in diseases as different as cancer and HD. The latter is the most common hereditary neurodegenerative disorder and muscle wasting is an important component of its pathology. In addition, possible therapeutic strategies for anti-cachectic treatment will be also discussed in the light of their translation into possible therapeutic approaches for HD
Coherence in scale-free networks of chaotic maps
We study fully synchronized states in scale-free networks of chaotic logistic
maps as a function of both dynamical and topological parameters. Three
different network topologies are considered: (i) random scale-free topology,
(ii) deterministic pseudo-fractal scale-free network, and (iii) Apollonian
network. For the random scale-free topology we find a coupling strength
threshold beyond which full synchronization is attained. This threshold scales
as , where is the outgoing connectivity and depends on the
local nonlinearity. For deterministic scale-free networks coherence is observed
only when the coupling strength is proportional to the neighbor connectivity.
We show that the transition to coherence is of first-order and study the role
of the most connected nodes in the collective dynamics of oscillators in
scale-free networks.Comment: 9 pages, 8 figure
Scattering by nonspherical systems
Scattering by nonspherical particles with size of order of wavelength - scattering by axisymmetric penetrable particles using approximate matching of boundary condition
Basel II, External Ratings and Adverse Selection
This paper will describe and analyse the development of Basel II Capital Accord and will focus on the use of external ratings in the Standardized Approach in Basel II. Furthermore it will examine the problem of adverse selection which appears in Basel II as a result from the proposal for the use of external ratings in determining the risk weights in the standardized approach. The paper will also attempt to find possible solutions to the adverse selection problem by discussing two similar models, and derive implications from them.Basel II, external ratings, adverse selection, rating agencies, standardized approach
Intraoperative detection of blood vessels with an imaging needle during neurosurgery in humans
Intracranial hemorrhage can be a devastating complication associated with needle biopsies of the brain. Hemorrhage can occur to vessels located adjacent to the biopsy needle as tissue is aspirated into the needle and removed. No intraoperative technology exists to reliably identify blood vessels that are at risk of damage. To address this problem, we developed an “imaging needle” that can visualize nearby blood vessels in real time. The imaging needle contains a miniaturized optical coherence tomography probe that allows differentiation of blood flow and tissue. In 11 patients, we were able to intraoperatively detect blood vessels (diameter, \u3e500 μm) with a sensitivity of 91.2% and a specificity of 97.7%. This is the first reported use of an optical coherence tomography needle probe in human brain in vivo. These results suggest that imaging needles may serve as a valuable tool in a range of neurosurgical needle interventions
The influence of electron collisions on non-LTE Li line formation in stellar atmospheres
The influence of the uncertainties in the rate coefficient data for
electron-impact excitation and ionization on non-LTE Li line formation in cool
stellar atmospheres is investigated. We examine the electron collision data
used in previous non-LTE calculations and compare them to recent calculations
that use convergent close-coupling (CCC) techniques and to our own calculations
using the R-matrix with pseudostates (RMPS) method. We find excellent agreement
between rate coefficients from the CCC and RMPS calculations, and reasonable
agreement between these data and the semi-empirical data used in non-LTE
calculations up to now. The results of non-LTE calculations using the old and
new data sets are compared and only small differences found: about 0.01 dex (~
2%) or less in the abundance corrections. We therefore conclude that the
influence on non-LTE calculations of uncertainties in the electron collision
data is negligible. Indeed, together with the collision data for the charge
exchange process Li(3s) + H Li^+ + H^- now available, and barring the
existence of an unknown important collisional process, the collisional data in
general is not a source of significant uncertainty in non-LTE Li line formation
calculations.Comment: 8 pages, accepted by Astronomy and Astrophysics; Replaced with minor
corrections following proof
Mechanisms for Lasing with Cold Atoms as the Gain Medium
We realize a laser with a cloud of cold rubidium atoms as gain medium, placed
in a low-finesse cavity. Three different regimes of laser emission are observed
corresponding respectively to Mollow, Raman and Four Wave Mixing mechanisms. We
measure an output power of up to 300 W and present the main properties of
these different lasers in each regime
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