1,982 research outputs found
A molecular signature of myalgia in myotonic dystrophy 2
Background: Chronic muscle pain affects close to 20% of the population and is a major health burden. The underlying mechanisms of muscle pain are difficult to investigate as pain presents in patients with very diverse histories. Treatment options are therefore limited and not tailored to underlying mechanisms. To gain insight into the pathophysiology of myalgia we investigated a homogeneous group of patients suffering from myotonic dystrophy type 2 (DM2), a monogenic disorder presenting with myalgia in at least 50% of affected patients. Methods: After IRB approval we performed an observational cross-sectional cohort study and recruited 42 patients with genetically confirmed DM2 plus 20 healthy age and gender matched control subjects. All participants were subjected to an extensive sensory-testing protocol. In addition, RNA sequencing was performed from 12 muscle biopsy specimens obtained from DM2 patients.
Findings: Clinical sensory testing as well as RNA sequencing clearly separated DM2 myalgic from non-myalgia patients and also from healthy controls. In particular pressure pain thresholds were significantly lowered for all muscles tested in myalgic DM2 patients but were not significantly different between non-myalgic patients and healthy controls. The expression of fourteen muscle expressed genes in myalgic patients was significantly up or down-regulated in myalgic compared to non-myalgic DM2 patients. Interpretation: Our data support the idea that molecular changes in the muscles of DM2 patients are associated with muscle pain. Further studies should address whether muscle-specific molecular pathways play a significant role in myalgia in order to facilitate the development of mechanism-based therapeutic strategies to treat musculoskeletal pain
Nonequilibrium : Antiscreening and Inverted Populations from Nonlocal Correlations
We study the dynamics of screening in photodoped Mott insulators with long-ranged interactions using a nonequilibrium implementation of the GW plus extended dynamical mean-field theory formalism. Our study demonstrates that the complex interplay of the injected carriers with bosonic degrees of freedom (charge fluctuations) can result in long-lived transient states with properties that are distinctly different from those of thermal equilibrium states. Systems with strong nonlocal interactions are found to exhibit a self-sustained population inversion of the doublons and holes. This population inversion leads to low-energy antiscreening which can be detected in time- resolved electron-energy-loss spectra
The X-ray Spectrum and Light Curve of Supernova 1995N
We report on multi-epoch X-ray observations of the Type IIn (narrow emission
line) supernova SN 1995N with the ROSAT and ASCA satellites. The January 1998
ASCA X-ray spectrum is well fitted by a thermal bremsstrahlung (kT~10 keV,
N_H~6e20 cm^-2) or power-law (alpha~1.7, N_H~1e21 cm^-2) model. The X-ray light
curve shows evidence for significant flux evolution between August 1996 and
January 1998: the count rate from the source decreased by 30% between our
August 1996 and August 1997 ROSAT observations, and the X-ray luminosity most
likely increased by a factor of ~2 between our August 1997 ROSAT and January
1998 ASCA observations, although evolution of the spectral shape over this
interval is not ruled out. The high X-ray luminosity, L_X~1e41 erg/sec, places
SN 1995N in a small group of Type IIn supernovae with strong circumstellar
interaction, and the evolving X-ray luminosity suggests that the circumstellar
medium is distributed inhomogeneously.Comment: MNRAS accepted. 6 pages, 2 figures; uses mn.sty and psfi
Theoretical characterization of a model of aragonite crystal orientation in red abalone nacre
Nacre, commonly known as mother-of-pearl, is a remarkable biomineral that in
red abalone consists of layers of 400-nm thick aragonite crystalline tablets
confined by organic matrix sheets, with the crystal axes of the
aragonite tablets oriented to within 12 degrees from the normal to the
layer planes. Recent experiments demonstrate that this orientational order
develops over a distance of tens of layers from the prismatic boundary at which
nacre formation begins.
Our previous simulations of a model in which the order develops because of
differential tablet growth rates (oriented tablets growing faster than
misoriented ones) yield patterns of tablets that agree qualitatively and
quantitatively with the experimental measurements. This paper presents an
analytical treatment of this model, focusing on how the dynamical development
and eventual degree of order depend on model parameters. Dynamical equations
for the probability distributions governing tablet orientations are introduced
whose form can be determined from symmetry considerations and for which
substantial analytic progress can be made. Numerical simulations are performed
to relate the parameters used in the analytic theory to those in the
microscopic growth model. The analytic theory demonstrates that the dynamical
mechanism is able to achieve a much higher degree of order than naive estimates
would indicate.Comment: 20 pages, 3 figure
Community health workers at the dawn of a new era: 3. Programme governance
Background: Community health workers (CHWs) can play a critical role in primary healthcare and are seen widely
as important to achieving the health-related Sustainable Development Goals (SDGs). The COVID-19 pandemic has
emphasized the key role of CHWs. Improving how CHW programmes are governed is increasingly recognized as
important for achieving universal access to healthcare and other health-related goals. This paper, the third in a series
on “Community Health Workers at the Dawn of a New Era”, aims to raise critical questions that decision-makers need
to consider for governing CHW programmes, illustrate the options for governance using examples of national CHW
programmes, and set out a research agenda for understanding how CHW programmes are governed and how this
can be improved.
Methods: We draw from a review of the literature as well as from the knowledge and experience of those involved in
the planning and management of CHW programmes.
Results: Governing comprises the processes and structures through which individuals, groups, programmes, and
organizations exercise rights, resolve diferences, and express interests. Because CHW programmes are located
between the formal health system and communities, and because they involve a wide range of stakeholders, their
governance is complex. In addition, these programmes frequently fall outside of the governance structures of the
formal health system or are poorly integrated with it, making governing these programmes more challenging. We
discuss the following important questions that decision-makers need to consider in relation to governing CHW programmes: (1) How and where within political structures are policies made for CHW programmes? (2) Who implements
decisions regarding CHW programmes and at what levels of government? (3) What laws and regulations are needed
to support the programme? (4) How should the programme be adapted across diferent settings or groups within the
country or region?
Conclusion: The most appropriate and acceptable models for governing CHW programmes depend on communities, on local health systems, and on the political system in which the programme is located. Stakeholders in each
setting need to consider what systems are currently in place and how they might be adapted to local needs and
systems
Symmetry Breaking of Relativistic Multiconfiguration Methods in the Nonrelativistic Limit
The multiconfiguration Dirac-Fock method allows to calculate the state of
relativistic electrons in atoms or molecules. This method has been known for a
long time to provide certain wrong predictions in the nonrelativistic limit. We
study in full mathematical details the nonlinear model obtained in the
nonrelativistic limit for Be-like atoms. We show that the method with sp+pd
configurations in the J=1 sector leads to a symmetry breaking phenomenon in the
sense that the ground state is never an eigenvector of L^2 or S^2. We thereby
complement and clarify some previous studies.Comment: Final version, to appear in Nonlinearity. Nonlinearity (2010) in
pres
Mesoscopic Electron and Phonon Transport through a Curved Wire
There is great interest in the development of novel nanomachines that use
charge, spin, or energy transport, to enable new sensors with unprecedented
measurement capabilities. Electrical and thermal transport in these mesoscopic
systems typically involves wave propagation through a nanoscale geometry such
as a quantum wire. In this paper we present a general theoretical technique to
describe wave propagation through a curved wire of uniform cross-section and
lying in a plane, but of otherwise arbitrary shape. The method consists of (i)
introducing a local orthogonal coordinate system, the arclength and two locally
perpendicular coordinate axes, dictated by the shape of the wire; (ii)
rewriting the wave equation of interest in this system; (iii) identifying an
effective scattering potential caused by the local curvature; and (iv), solving
the associated Lippmann-Schwinger equation for the scattering matrix. We carry
out this procedure in detail for the scalar Helmholtz equation with both
hard-wall and stress-free boundary conditions, appropriate for the mesoscopic
transport of electrons and (scalar) phonons. A novel aspect of the phonon case
is that the reflection probability always vanishes in the long-wavelength
limit, allowing a simple perturbative (Born approximation) treatment at low
energies. Our results show that, in contrast to charge transport, curvature
only barely suppresses thermal transport, even for sharply bent wires, at least
within the two-dimensional scalar phonon model considered. Applications to
experiments are also discussed.Comment: 9 pages, 11 figures, RevTe
New XMM-Newton analysis of three bright X-ray sources in M31 globular clusters, including a new black hole candidate
We present detailed analysis of three globular cluster X-ray sources in the
XMM-Newton extended survey of M31. The X-ray counterpart to the M31 globular
cluster Bo 45 (XBo 45) was observed with XMM-Newton on 2006 December 26. Its
combined pn+MOS 0.3--10 keV lightcurve exhibited a r.m.s variability of ~10%,
and its 0.3--7.0 keV emission spectrum was well described by an absorbed power
law with photon index 1.440.12. Its variability and emission is
characteristic of low mass X-ray binaries (LMXBs) in the low-hard state,
whether the accretor is a neutron star or black hole. Such behaviour is
typically observed at luminosities \la10% Eddington. However, XBo 45
exhibited this behaviour at an unabsorbed, 0.3--10 keV luminosity of
2.5 erg s, or{~140%} Eddington for a 1.4
neutron star accreting hydrogen. Hence, we identify XBo 45 as a new
candidate black hole LMXB. XBo 45 appears to have been consistently bright for
~30 years, consistent with theoretical prediction for a globular cluster black
hole binary formed via tidal capture. Bo 375 was observed in the 2007, January
2 XMM-Newton observation, and has a two-component spectrum that is typical for
a bright neutron star LMXB. Bo 135 was observed in the same field as Bo 45, and
could contain either a black hole or neutron star.Comment: Accepted by ApJ, 16 pages, 5 figures. This version includes the final
changes made at the request of the refere
Thymic plasmacytoid dendritic cells are susceptible to productive HIV-1 infection and efficiently transfer R5 HIV-1 to thymocytes in vitro
<p>Abstract</p> <p>Background</p> <p>HIV-1 infection of the thymus contributes to the defective regeneration and loss of CD4<sup>+ </sup>T cells in HIV-1-infected individuals. As thymic dendritic cells (DC) are permissive to infection by HIV-1, we examined the ability of thymic DC to enhance infection of thymocytes which may contribute to the overall depletion of CD4<sup>+ </sup>T cells. We compared productive infection in isolated human thymic and blood CD11c<sup>+ </sup>myeloid DC (mDC) and CD123<sup>+ </sup>plasmacytoid DC (pDC) using enhanced green fluorescent protein (EGFP) CCR5 (R5)-tropic NL(AD8) and CXCR4 (X4)-tropic NL4-3 HIV-1 reporter viruses. Transfer of productive HIV-1 infection from thymic mDC and pDC was determined by culturing these DC subsets either alone or with sorted thymocytes.</p> <p>Results</p> <p>Productive infection was observed in both thymic pDC and mDC following exposure to R5 HIV-1 and X4 HIV-1. Thymic pDC were more frequently productively infected by both R5 and X4 HIV-1 than thymic mDC (p = 0.03; n = 6). Thymic pDC efficiently transferred productive R5 HIV-1 infection to both CD3<sup>hi </sup>(p = 0.01; mean fold increase of 6.5; n = 6) and CD3<sup>lo </sup>thymocytes (mean fold increase of 1.6; n = 2). In comparison, transfer of productive infection by thymic mDC was not observed for either X4 or R5 HIV-1.</p> <p>Conclusions</p> <p>The capacity of thymic pDC to efficiently transfer R5 HIV-1 to both mature and immature thymocytes that are otherwise refractory to R5 virus may represent a pathway to early infection and impaired production of thymocytes and CD4<sup>+ </sup>T cells in HIV-1-infected individuals.</p
Master integrals with 2 and 3 massive propagators for the 2-loop electroweak form factor - planar case
We compute the master integrals containing 2 and 3 massive propagators
entering the planar amplitudes of the 2-loop electroweak form factor. The
masses of the , and Higgs bosons are assumed to be degenerate. This work
is a continuation of our previous evaluation of master integrals containing at
most 1 massive propagator. The 1/\epsilon poles and the finite parts are
computed exactly in terms of a {\it new} class of 1-dimensional harmonic
polylogarithms of the variable x, with \epsilon=2-D/2 and D the pace-time
dimension. Since thresholds and pseudothresholds in s=\pm 4m^2 do appear in
addition to the old ones in s=0,\pm m^2, an extension of the basis function set
involving complex constants and radicals is introduced, together with a set of
recursion equations to reduce integrals with semi-integer powers. It is shown
that the basic properties of the harmonic polylogarithms are maintained by the
generalization. We derive small-momentum expansions |s| << m^2 of all the
6-denominator amplitudes. We also present large momentum expansions |s| >> m^2
of all the 6-denominator amplitudes which can be represented in terms of
ordinary harmonic polylogarithms. Comparison with previous results in the
literature is performed finding complete agreement.Comment: 68 pages, 7 figure
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