Summary Improvements in acute burn care have enabled patients to survive massive burns that would have once been fatal. Now up to 70% of patients develop hypertrophic scars after burns. The ...functional and psychosocial sequelae remain a major rehabilitative challenge, decreasing quality of life and delaying reintegration into society. Approaches to optimise healing potential of burn wounds use targeted wound care and surgery to minimise the development of hypertrophic scarring. Such approaches often fail, and modulation of the established scar is continued although the optimal indication, timing, and combination of therapies have yet to be established. The need for novel treatments is paramount, and future efforts to improve outcomes and quality of life should include optimisation of wound healing to attenuate or prevent hypertrophic scarring, well-designed trials to confirm treatment efficacy, and further elucidation of molecular mechanisms to allow development of new preventive and therapeutic strategies.
IEEETrans.Nucl.Sci.52:2778-2785,2005 The cosmological revolution of 1997 has established that (at least long
duration) gamma-ray bursts (GRB) are among the most energetic events in the
Universe and ...occur at cosmological distances. The ECLAIRs micro-satellite, to
be launched in 2009, will provide multi-wavelength observations for
astrophysical studies of GRB and for their possible use as cosmological probes.
It is expected to be the only space borne GRB trigger available for ground
based robotic telescopes operational at that time. This paper presents the
ECLAIRs project and its status. An X/gamma-ray camera onboard ECLAIRs with a
wide field of view of 2 sr, will detect ~100 GRB/yr in the 4-50 keV energy
range, localize the GRB with a precision of ~10 arcmin on the sky, and transmit
this information to the ground in near real-time, as a GRB trigger for ground
based optical telescopes. Inspired by the INTEGRAL imager IBIS, it is based on
a CdTe detection plane covering 1000 cm^2, placed 35 cm below a coded mask. An
optical camera, sensitive to magnitude-15 stars, covering up to 1/4th of the
X/gamma-ray camera's field of view, will observe the prompt emission and a
possible precursor of ~10 GRB/yr in the visible-band. Used in a continuous
acquisition mode at a rate of ~5 images/s dumped into an on-board memory, a GRB
event sent by the X/gamma-ray camera triggers a seek-back in memory for the GRB
optical precursor. The full X/gamma-ray and visible-band data of a GRB are sent
to ground when a high data-rate telemetry ground receiver is reachable.
The X-ray burster 1E1724-3045 located in the globular cluster Terzan 2 is known as one of the persistent (though variable) hard X-ray sources as shown by the SIGMA observations of the Galactic Center ...region. 1E1724-3045 was observed with the PCA and HEXTE experiments onboard the RXTE on November 1996 for about 100 ksec. The broad band spectral capability and sensitivity of RXTE enables us to study simultaneously the X-ray (2-20 keV) and hard X-ray components (E>20 keV) of this source. During the observation, this ``Atoll'' source was in its ``Island'' state characterized by a hard Comptomized spectrum with an electron temperature kTe~29 keV, an optical depth of 2.9 (spherical geometry) and a temperature for the ``seed'' photons of 1.2 keV. Below 5 keV, there is a soft excess which we fit with a blackbody of kTbb=0.7 keV. The Comptonization temperature is significantly lower those observed for black holes candidates in their low luminosity states (kTe >~ 50 keV). Finally, our observation allows us to associate the presence of an hard tail with a low luminosity X-ray state (1-20 keV luminosity of 10^37 erg/s at 7.7 kpc).
Proc. 39th ESLAB Symposium, Noordwijk, 19-21 April 2005, SP-588,
p. 141-149, F. Favata, A. Gimenez. eds An extensive theoretical literature predicts that X-ray Polarimetry can
directly determine ...relevant physical and geometrical parameters of
astrophysical sources, and discriminate between models further than allowed by
spectral and timing data only. X-ray Polarimetry can also provide tests of
Fundamental Physics. A high sensitivity polarimeter in the focal plane of a New
Generation X-ray telescope could open this new window in the High Energy Sky.
AIP Conf.Proc.599:518-521,1999 The burster and dipper Low Mass X-ray Binary (LMXB) 4U1915-05 (also known as
XB1916-053) was observed by the Rossi X-ray Timing Explorer (RXTE) 19 times for
a total ...exposure of 140 ks between 1996 February and October. Here we report on
the discovery of Low Frequency (10-40 Hz) Quasi-Periodic Oscillations (LFQPOs)
from 4U1915-05. The properties of the LFQPOs are related to the presence of the
High Frequency QPOs (HFQPOs) detected simultaneously. We have observed a
correlation between the LFQPO frequency and source count rate, as well as a
correlation (linear) between the LFQPOs and HFQPOs. Both results cannot be
explained by a Beat Frequency Model (BFM). They are also hardly compatible with
predictions from the inner disk precession model.
We report on the development of an innovative CdTe detector plane (DPIX) optimized for the detection and localization of gamma-ray bursts in the X-ray band (below 100 keV). DPIX is part of an R&D ...program funded by the French Space Agency (CNES). DPIX builds upon the heritage of the ISGRI instrument, currently operating with great success on the ESA INTEGRAL mission. DPIX is an assembly of 200 elementary modules (XRDPIX) equipped with 32 CdTe Schottky detectors (4x4 mm2, 1 mm thickness) produced by ACRORAD Co. LTD. in Japan. These detectors offer good energy response up to 100 keV. Each XRDPIX is readout by the very low noise front-end electronics chip IDeF-X, currently under development at CEA/DSM/DAPNIA. In this paper, we describe the design of XRDPIX, the main features of the IDeF-X chip, and will present preliminary results of the reading out of one CdTe Schottky detector by the IDeF-X V1.0 chip. A low-energy threshold around 2.7 keV has been measured. This is to be compared with the 12-15 keV threshold of the ISGRI-INTEGRAL and BAT-SWIFT instruments, which both use similar detector material.
Headings in the French weekly publications Le Nouvel Observateur & Telerama provide references to titles of songs, films, plays, & books, & to well-known quotations. The instructor can use them to ...orient students to these aspects of French culture & as models for series of student-invented headings with similar reference. J. Hitchcock
The bright persistent X-ray source and type I X-ray burster 1E1724-3045
located in the globular cluster Terzan 2 was observed by ASCA for about 10 ksec
on September 24-25th, 1995 while it was in its ...hard state, with a luminosity of
\~6x10^36 erg/s in the 0.5-10 keV band (d=7.7 kpc). The ASCA spectrum is hard,
and reveals the presence of a soft component below 2-3 keV. When combined with
non simultaneous RXTE/HEXTE data, we show that the ASCA spectrum can be
adequately fitted by a Comptonization model for which the electron temperature
is ~30 keV, the optical depth is ~3 for a spherical scattering cloud. The soft
component carries off about 13%, and 35% of the 0.1-200 keV luminosity for a
blackbody and disk blackbody fit respectively. It is more likely to arise from
the accretion disk, whereas the hard Comptonized component is generated in a
hot boundary layer interior to the disk. The column density measured towards
the source (NH=10^22 cm^-2) is consistent with the value expected from the
optical reddening of the cluster. No emission lines were detected, and an upper
limit of 30 eV for the equivalent width of a 6.4 keV line (sigma=0.1 keV) has
been derived.
The Burst and Transient Source Experiment (BATSE), aboard the Compton Gamma
Ray Observatory (CGRO), provided a record of the low-energy gamma-ray sky
(20-1000 keV) between 1991 April and 2000 May ...(9.1y). Using the Earth
Occultation Technique to extract flux information, a catalog of sources using
data from the BATSE large area detectors has been prepared. The first part of
the catalog consists of results from the monitoring of 58 sources, mostly
Galactic. For these sources, we have included tables of flux and spectral data,
and outburst times for transients. Light curves (or flux histories) have been
placed on the world wide web. We then performed a deep-sampling of 179 objects
(including the aforementioned 58 objects) combining data from the entire 9.1y
BATSE dataset. Source types considered were primarily accreting binaries, but a
small number of representative active galaxies, X-ray-emitting stars, and
supernova remnants were also included. The deep sample results include definite
detections of 83 objects and possible detections of 36 additional objects. The
definite detections spanned three classes of sources: accreting black hole and
neutron star binaries, active galaxies and supernova remnants. Flux data for
the deep sample are presented in four energy bands: 20-40, 40-70, 70-160, and
160-430 keV. The limiting average flux level (9.1 y) for the sample varies from
3.5 to 20 mCrab (5 sigma) between 20 and 430 keV, depending on systematic
error, which in turn is primarily dependent on the sky location. To strengthen
the credibility of detection of weaker sources (5-25 mCrab), we generated Earth
occultation images, searched for periodic behavior using FFT and epoch folding
methods, and critically evaluated the energy-dependent emission in the four
flux bands.
Summary Histiocytoses are disorders characterised by inflammation and the accumulation of cells derived from the monocyte and macrophage lineages, which results in tissue damage. Although they are ...often considered rare disorders with protean clinical manifestations, considerable advances in the understanding of their genetics have led to increased clinical recognition of these conditions, and fuelled further insights into their pathogenesis. In this Review, we describe insights into the cells of origin, molecular pathology, clinical features, and treatment strategies for some of the most common histiocytic disorders, including Langerhans cell histiocytosis, Erdheim-Chester disease, and Rosai-Dorfman disease. With the discovery of recurrent mutations affecting the mitogen-activated protein kinase and mTOR–AKT pathways in some of these histiocytoses, our understanding of these diseases has now evolved from the concept of a primary inflammatory condition to that of a clonal neoplastic disease. This understanding has led to the development of effective mechanism-based therapeutic strategies for patients with histiocytic diseases.
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