76 research outputs found
Inherited epithelial transporter disorders—an overview
Summary: In the late 1990s, the identification of transporters and transporter-associated genes progressed substantially due to the development of new cloning approaches such as expression cloning and, subsequently, to the implementation of the human genome project. Since then, the role of many transporter genes in human diseases has been elucidated. In this overview, we focus on inherited disorders of epithelial transporters. In particular, we review genetic defects of the genes encoding glucose transporters (SLC2 and SLC5 families) and amino acid transporters (SLC1, SLC3, SLC6 and SLC7 families
Synthetic X-ray and radio maps for two different models of Stephan's Quintet
We present simulations of the compact galaxy group Stephan's Quintet (SQ)
including magnetic fields, performed with the N-body/smoothed particle
hydrodynamics (SPH) code \textsc{Gadget}. The simulations include radiative
cooling, star formation and supernova feedback. Magnetohydrodynamics (MHD) is
implemented using the standard smoothed particle magnetohydrodynamics (SPMHD)
method. We adapt two different initial models for SQ based on Renaud et al. and
Hwang et al., both including four galaxies (NGC 7319, NGC 7320c, NGC 7318a and
NGC 7318b). Additionally, the galaxies are embedded in a magnetized, low
density intergalactic medium (IGM). The ambient IGM has an initial magnetic
field of G and the four progenitor discs have initial magnetic fields
of G. We investigate the morphology, regions of star
formation, temperature, X-ray emission, magnetic field structure and radio
emission within the two different SQ models. In general, the enhancement and
propagation of the studied gaseous properties (temperature, X-ray emission,
magnetic field strength and synchrotron intensity) is more efficient for the SQ
model based on Renaud et al., whose galaxies are more massive, whereas the less
massive SQ model based on Hwang et al. shows generally similar effects but with
smaller efficiency. We show that the large shock found in observations of SQ is
most likely the result of a collision of the galaxy NGC 7318b with the IGM.
This large group-wide shock is clearly visible in the X-ray emission and
synchrotron intensity within the simulations of both SQ models. The order of
magnitude of the observed synchrotron emission within the shock front is
slightly better reproduced by the SQ model based on Renaud et al., whereas the
distribution and structure of the synchrotron emission is better reproduced by
the SQ model based on Hwang et al..Comment: 20 pages, 15 figures, accepted to MNRA
Learning Informative Health Indicators Through Unsupervised Contrastive Learning
Condition monitoring is essential to operate industrial assets safely and
efficiently. To achieve this goal, the development of robust health indicators
has recently attracted significant attention. These indicators, which provide
quantitative real-time insights into the health status of industrial assets
over time, serve as valuable tools for fault detection and prognostics. In this
study, we propose a novel and universal approach to learn health indicators
based on unsupervised contrastive learning. Operational time acts as a proxy
for the asset's degradation state, enabling the learning of a contrastive
feature space that facilitates the construction of a health indicator by
measuring the distance to the healthy condition. To highlight the universality
of the proposed approach, we assess the proposed contrastive learning framework
in two distinct tasks - wear assessment and fault detection - across two
different case studies: a milling machines case study and a real condition
monitoring case study of railway wheels from operating trains. First, we
evaluate if the health indicator is able to learn the real health condition on
a milling machine case study where the ground truth wear condition is
continuously measured. Second, we apply the proposed method on a real case
study of railway wheels where the ground truth health condition is not known.
Here, we evaluate the suitability of the learned health indicator for fault
detection of railway wheel defects. Our results demonstrate that the proposed
approach is able to learn the ground truth health evolution of milling machines
and the learned health indicator is suited for fault detection of railway
wheels operated under various operating conditions by outperforming
state-of-the-art methods. Further, we demonstrate that our proposed approach is
universally applicable to different systems and different health conditions
Comparative adverse effects, perceptions and attitudes related to BNT162b2, mRNA1273, or JNJ-78436735 SARS-CoV-2 vaccines: A population-based longitudinal cohort
Importance Long-term control of SARS-CoV-2 requires effective vaccination strategies. This has been challenged by public mistrust and spread of misinformation regarding vaccine safety. Hence, better understanding and communication on the longer-term and comparative experiences of general population individuals following SARS-CoV-2 vaccination are required.
Objective To evaluate and compare self-reported adverse effects following SARS-CoV-2 vaccination, participants’ perceptions regarding vaccinations and their compliance with recommended public health measures.
Design, Setting and Participants Population-based longitudinal cohort of 575 adults, randomly selected from all individuals presenting to the reference vaccination center of the Canton of Zurich, Switzerland, for receipt of BNT162b2, mRNA1273, or JNJ-78436735
Adverse effects, perceptions and attitudes related to BNT162b2, mRNA-1273 or JNJ-78436735 SARS-CoV-2 vaccines: Population-based cohort
Long-term control of SARS-CoV-2 requires effective vaccination strategies. This has been challenged by public mistrust and the spread of misinformation regarding vaccine safety. Better understanding and communication of the longer-term and comparative experiences of individuals in the general population following vaccination are required. In this population-based longitudinal study, we included 575 adults, randomly selected from all individuals presenting to a Swiss reference vaccination center, for receipt of BNT162b2, mRNA1273, or JNJ-78436735. We assessed the prevalence, onset, duration, and severity of self-reported adverse effects over 12 weeks following vaccination. We additionally evaluated participants' perceptions of vaccines, trust in public health authorities and pharmaceutical companies, and compliance with public health measures. Most participants reported at least one adverse effect within 12 weeks following vaccination. Adverse effects were mostly mild or moderate, resolved within three days, and rarely resulted in anaphylaxis or hospitalizations. Female sex, younger age, higher education, and receipt of mRNA-1273 were associated with reporting adverse effects. Compared to JNJ-78436735 recipients, a higher proportion of mRNA vaccine recipients agreed that vaccination is important, and trusted public health authorities. Our findings provide real-world estimates of the prevalence of adverse effects following SARS-CoV-2 vaccination and highlight the importance of transparent communication to ensure the success of current or future vaccination campaigns
Phase transitions in two-dimensional model colloids in a one-dimensional external potential
Two-dimensional melting transitions for model colloids in presence of a
one-dimensional external periodic potential are investigated using Monte Carlo
simulation and Finite Size Scaling techniques. Here we explore a hard disk
system with commensurability ratio , where is the
mean distance between the disks and the period of the external potential.
Three phases, the modulate liquid, the locked smectic and the locked floating
solid are observed, in agreement with other experimental and analytical
studies. Various statistical quantities like order parameters, their cumulants
and response functions, are used to obtain a phase diagram for the transitions
between these three phases.Comment: Some changes in order to meet with published versio
Constrained Hyperbolic Divergence Cleaning for Smoothed Particle Magnetohydrodynamics
We present a constrained formulation of Dedner et al's hyperbolic/parabolic
divergence cleaning scheme for enforcing the \nabla\dot B = 0 constraint in
Smoothed Particle Magnetohydrodynamics (SPMHD) simulations. The constraint we
impose is that energy removed must either be conserved or dissipated, such that
the scheme is guaranteed to decrease the overall magnetic energy. This is shown
to require use of conjugate numerical operators for evaluating \nabla\dot B and
\nabla{\psi} in the SPMHD cleaning equations. The resulting scheme is shown to
be stable at density jumps and free boundaries, in contrast to an earlier
implementation by Price & Monaghan (2005). Optimal values of the damping
parameter are found to be {\sigma} = 0.2-0.3 in 2D and {\sigma} = 0.8-1.2 in
3D. With these parameters, our constrained Hamiltonian formulation is found to
provide an effective means of enforcing the divergence constraint in SPMHD,
typically maintaining average values of h |\nabla\dot B| / |B| to 0.1-1%, up to
an order of magnitude better than artificial resistivity without the associated
dissipation in the physical field. Furthermore, when applied to realistic, 3D
simulations we find an improvement of up to two orders of magnitude in momentum
conservation with a corresponding improvement in numerical stability at
essentially zero additional computational expense.Comment: 28 pages, 25 figures, accepted to J. Comput. Phys. Movies at
http://www.youtube.com/playlist?list=PL215D649FD0BDA466 v2: fixed inverted
figs 1,4,6, and several color bar
The Interplay of Magnetic Fields, Fragmentation and Ionization Feedback in High-Mass Star Formation
Massive stars disproportionately influence their surroundings. How they form
has only started to become clear recently through radiation gas dynamical
simulations. However, until now, no simulation has simultaneously included both
magnetic fields and ionizing radiation. Here we present the results from the
first radiation-magnetohydrodynamical (RMHD) simulation including ionization
feedback, comparing an RMHD model of a 1000 M_sol rotating cloud to earlier
radiation gas dynamical models with the same initial density and velocity
distributions. We find that despite starting with a strongly supercritical mass
to flux ratio, the magnetic field has three effects. First, the field offers
locally support against gravitational collapse in the accretion flow,
substantially reducing the amount of secondary fragmentation in comparison to
the gas dynamical case. Second, the field drains angular momentum from the
collapsing gas, further increasing the amount of material available for
accretion by the central, massive, protostar, and thus increasing its final
mass by about 50% from the purely gas dynamical case. Third, the field is wound
up by the rotation of the flow, driving a tower flow. However, this flow never
achieves the strength seen in low-mass star formation simulations for two
reasons: gravitational fragmentation disrupts the circular flow in the central
regions where the protostars form, and the expanding H II regions tend to
further disrupt the field geometry. Therefore, outflows driven by ionization
heating look likely to be more dynamically important in regions of massive star
formation.Comment: ApJ in pres
Magnetic field amplification and X-ray emission in galaxy minor mergers
We investigate the magnetic field evolution in a series of galaxy minor
mergers using the N-body/smoothed particle hydrodynamics (SPH) code
\textsc{Gadget}. The simulations include the effects of radiative cooling, star
formation and supernova feedback. Magnetohydrodynamics (MHD) is implemented
using the SPH method. We present 32 simulations of binary mergers of disc
galaxies with mass ratios of 2:1 up to 100:1, whereby we have additionally
varied the initial magnetic field strengths, disc orientations and resolutions.
We investigate the amplification of a given initial magnetic field within the
galaxies and an ambient intergalactic medium (IGM) during the interaction. We
find that the magnetic field strengths of merger remnants with mass ratios up
to 10:1 saturate at a common value of several G. For higher mass ratios,
the field strength saturates at lower values. The saturation values correspond
to the equipartition value of magnetic and turbulent energy density. The
initial magnetization, disc orientation and numerical resolution show only
minor effects on the saturation value of the magnetic field. We demonstrate
that a higher impact energy of the progenitor galaxies leads to a more
efficient magnetic field amplification. The magnetic and turbulent energy
densities are higher for larger companion galaxies, consistent with the higher
impact energy supplied to the system. We present a detailed study of the
evolution of the temperature and the bolometric X-ray luminosity within the
merging systems. Thereby we find that magnetic fields cause a more efficient
increase of the IGM temperature and the corresponding IGM X-ray luminosity
after the first encounter. However, the presence of magnetic fields does not
enhance the total X-ray luminosity. Generally, the final value of the X-ray
luminosity is even clearly lower for higher initial magnetic fields.Comment: 20 pages, 12 figures. Submitted to MNRA
Protostellar outflows with Smoothed Particle Magnetohydrodynamics (SPMHD)
The protostellar collapse of a molecular cloud core is usually accompanied by
outflow phenomena. The latter are thought to be driven by magnetorotational
processes from the central parts of the protostellar disc. While several 3D
AMR/nested grid studies of outflow phenomena in collapsing magnetically
supercritical dense cores have been reported in the literature, so far no such
simulation has been performed using the Smoothed Particle Hydrodynamics (SPH)
method. This is mainly due to intrinsic numerical difficulties in handling
magnetohydrodynamics within SPH, which only recently were partly resolved. In
this work, we use an approach where we evolve the magnetic field via the
induction equation, augmented with stability correction and divergence cleaning
schemes. We consider the collapse of a rotating core of one solar mass,
threaded by a weak magnetic field initially parallel to the rotation axis so
that the core is magnetically supercritical. We show, that Smoothed Particle
Magnetohydrodynamics (SPMHD) is able to handle the magnetorotational processes
connected with outflow phenomena, and to produce meaningful results which are
in good agreement with findings reported in the literature. Especially, our
numerical scheme allows for a quantitative analysis of the evolution of the
ratio of the toroidal to the poloidal magnetic field, which we performed in
this work.Comment: 5 pages, 4 figures. Accepted to MNRAS Letter
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