343 research outputs found
Osteopontin and `Melanoma Inhibitory Activity': Comparison of Two Serological Tumor Markers in Metastatic Uveal Melanoma Patients
Background: Evaluation of the protein osteopontin (OPN) as a potential new marker in comparison to melanoma inhibitory activity (MIA) for screening and detection of metastatic uveal melanoma. Methods: Plasma levels of 32 patients with uveal melanoma were analyzed for OPN and MIA by enzyme-linked immunosorbent assay (ELISA). Fourteen of these patients had clinically detectable liver metastases. Results: Median plasma concentration of OPN in patients with metastatic disease was 152.01 ng/ml compared to 47.39 ng/ml in patients without clinically detectable metastases (p < 0.001). The difference between the median MIA plasma levels in patients with (13.11 ng/ml) and patients without (5.64 ng/ml) metastatic disease was also statistically significant (p < 0.001). No correlation could be found between MIA or OPN levels and tumor height in patients without clinically detectable metastases. Conclusion: The proteins MIA and OPN seem to be promising tumor markers for the metastasis screening in patients with uveal melanoma. Copyright (C) 2009 S. Karger AG, Base
Is Smaller Always Better? - Evaluating Video Compression Techniques for Simulation Ensembles
We provide an evaluation of the applicability of video compression techniques for compressing visualization image databases that are often used for in situ visualization. Considering relevant practical implementation aspects, we identify relevant compression parameters, and evaluate video compression for several test cases, involving several data sets and visualization methods; we use three different video codecs. To quantify the benefits and drawbacks of video compression, we employ metrics for image quality, compression rate, and performance. The experiments discussed provide insight into good choices of parameter values, working well in the considered cases
Faraday rotation maps of disk galaxies
Faraday rotation is one of the most widely used observables to infer the
strength and configuration of the magnetic field in the ionised gas of the
Milky Way and nearby spiral galaxies. Here we compute synthetic Faraday
rotation maps at for a set of disk galaxies from the Auriga
high-resolution cosmological simulations, for different observer positions
within and outside the galaxy. We find that the strength of the Faraday
rotation of our simulated galaxies for a hypothetic observer at the solar
circle is broadly consistent with the Faraday rotation seen for the Milky Way.
The same holds for an observer outside the galaxy and the observed signal of
the nearby spiral galaxy M51. However, we also find that the structure and
angular power spectra of the synthetic all-sky Faraday rotation maps vary
strongly with azimuthal position along the solar circle. We argue that this
variation is a result of the structure of the magnetic field of the galaxy that
is dominated by an azimuthal magnetic field ordered scales of several kpc, but
has radial and vertical magnetic field components that are only ordered on
scales of 1-2 kpc. Because the magnetic field strength decreases exponentially
with height above the disk, the Faraday rotation for an observer at the solar
circle is dominated by the local environment. This represents a severe obstacle
for attempts to reconstruct the global magnetic field of the Milky Way from
Faraday rotation maps alone without including additional observables.Comment: 10 pages, 10 figures, accepted by MNRA
The role of cosmic ray pressure in accelerating galactic outflows
We study the formation of galactic outflows from supernova explosions (SNe)
with the moving-mesh code AREPO in a stratified column of gas with a surface
density similar to the Milky Way disk at the solar circle. We compare different
simulation models for SNe placement and energy feedback, including cosmic rays
(CR), and find that models that place SNe in dense gas and account for CR
diffusion are able to drive outflows with similar mass loading as obtained from
a random placement of SNe with no CRs. Despite this similarity, CR-driven
outflows differ in several other key properties including their overall
clumpiness and velocity. Moreover, the forces driving these outflows originate
in different sources of pressure, with the CR diffusion model relying on
non-thermal pressure gradients to create an outflow driven by internal pressure
and the random-placement model depending on kinetic pressure gradients to
propel a ballistic outflow. CRs therefore appear to be non-negligible physics
in the formation of outflows from the interstellar medium.Comment: 8 pages, 4 figures, accepted for publication in ApJL; movie of
simulated gas densities can be found here:
http://www.h-its.org/tap-images/galactic-outflows
Magnetic field amplification in cosmological zoom simulations from dwarf galaxies to galaxy groups
Magnetic fields are ubiquitous in the Universe. Recently, cosmological
simulations of galaxies have successfully begun to incorporate magnetic fields
and their evolution in galaxies and their haloes. However, so far they have
mostly focused on Milky Way-like galaxies. Here we analyse a sample of high
resolution cosmological zoom simulations of disc galaxies in haloes with mass
from to
, simulated with the Auriga galaxy formation model.
We show that with sufficient numerical resolution the magnetic field
amplification and saturation is converged. The magnetic field strength reaches
equipartition with turbulent energy density for galaxies in haloes with
. For galaxies in less
massive haloes, the magnetic field strength saturates at a fraction of
equipartition that decreases with decreasing halo mass. For our lowest mass
haloes, the magnetic field saturates significantly below of
equipartition. We quantify the resolution we need to obtain converged magnetic
field strengths and discuss our resolution requirements also in the context of
the IllustrisTNG cosmological box simulations. We show that, at ,
rotation-dominated galaxies in our sample exhibit for the most part an ordered
large scale magnetic field, with fewer field reversals in more massive
galaxies. Finally, we compare the magnetic fields in our cosmological galaxies
at with simulations of isolated galaxies in a collapsing halo setup. Our
results pave the way for detailed studies of cosmic rays and other physical
processes in similar cosmological galaxy simulations that crucially depend on
the strength and structure of magnetic fields.Comment: 18 pages, 12 figures, submitted to MNRAS, comments welcom
Improving the accuracy of soil moisture retrievals using the phase difference of the dual-polarization GNSS-R interference patterns
Soil moisture (SM) is a key parameter in the climate studies at a global scale and a very important parameter in applications such as precision agriculture at a local scale. The Global Navigation Satellite Systems Interference Pattern Technique (IPT) has proven to be a useful technique for the determination of SM, based on observations at vertical polarization (V-Pol) due to the Brewster angle. The IPT can be applied at both V-Pol and horizontal polarization (H-Pol) at the same time, observing the Brewster angle only at V-Pol. This letter presents a measurement technique based on tracking the phase difference between V-Pol and H-Pol interference patterns to improve the accuracy of the Brewster angle determination and, consequently, that of the SM retrievals. This technique benefits from the different phase behavior of the reflection coefficients between H-Pol and V-Pol in the angular observation range. To be sensitive to the phase difference, the Rayleigh criterion for smooth surfaces must be accomplished. This technique is not sensitive to topography as it is intrinsically corrected. Experimental results are presented to validate the proposed algorithm.Peer ReviewedPostprint (author’s final draft
Clinical relevance and utility of cetuximab-related changes in magnesium and calcium serum levels
Hypomagnesemia and hypocalcemia are common adverse events during cetuximab treatment. The influence of the chemotherapeutic combination on serum levels is unknown and the predictive value is currently under discussion. This analysis investigated 79 patients who had received cetuximab for at least 6 weeks in the day clinic of the Comprehensive Cancer Center, University of Munich. Calcium and magnesium serum levels were analyzed weekly; tumor response and adverse events were followed. Thirty-eight patients had metastatic colorectal cancer (mCRC) and the predictive value of hypomagnesemia was tested in these patients. During therapy, calcium serum levels decreased to about 97% of the baseline levels and were maintained for the duration of treatment. Magnesium levels showed a significant time-dependent decrease. Serum levels of magnesium were lower when cetuximab was combined with a platinum derivative. After a treatment duration of 12 weeks, magnesium levels decreased to 70% in platinum-treated patients, whereas they decreased to only 90% of baseline in patients who did not receive platinum therapy. In patients treated for mCRC, a decrease of serum magnesium below 95% of the baseline levels 14 days after initiating treatment separated patients significantly in terms of survival times. Magnesium levels decrease in a time-dependent manner during cetuximab therapy. As hypomagnesemia was more prominent in patients receiving platinum agents, magnesium measurements may be advised in these patients. In mCRC patients treated with cetuximab, day-14 magnesium serum levels correlated with treatment efficacy
The MillenniumTNG Project: The hydrodynamical full physics simulation and a first look at its galaxy clusters
Cosmological simulations are an important theoretical pillar for
understanding nonlinear structure formation in our Universe and for relating it
to observations on large scales. In several papers, we introduce our
MillenniumTNG (MTNG) project that provides a comprehensive set of
high-resolution, large volume simulations of cosmic structure formation aiming
to better understand physical processes on large scales and to help
interpreting upcoming large-scale galaxy surveys. We here focus on the full
physics box MTNG740 that computes a volume of with a
baryonic mass resolution of using
\textsc{arepo} with ~billion cells and the IllustrisTNG galaxy formation
model. We verify that the galaxy properties produced by MTNG740 are consistent
with the TNG simulations, including more recent observations. We focus on
galaxy clusters and analyse cluster scaling relations and radial profiles. We
show that both are broadly consistent with various observational constraints.
We demonstrate that the SZ-signal on a deep lightcone is consistent with Planck
limits. Finally, we compare MTNG740 clusters with galaxy clusters found in
Planck and the SDSS-8 RedMaPPer richness catalogue in observational space,
finding very good agreement as well. However, {\it simultaneously} matching
cluster masses, richness, and Compton- requires us to assume that the SZ
mass estimates for Planck clusters are underestimated by ~dex on average.
Thanks to its unprecedented volume for a high-resolution hydrodynamical
calculation, the MTNG740 simulation offers rich possibilities to study baryons
in galaxies, galaxy clusters, and in large scale structure, and in particular
their impact on upcoming large cosmological surveys.Comment: 18 pages, 14 figures, accepted for publication by MNRAS, comments
welcom
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