124 research outputs found
Diagnosis of periarticular osteoporosis in rheumatoid arthritis using digital X-ray radiogrammetry
Osteoporosis can manifest in two ways in rheumatoid arthritis: generalized bone loss, which may result from immobility, the inflammatory process per se and/or treatments such as steroids; and periarticular demineralization, which is probably due to local release of inflammatory agents. Digital X-ray radiogrammetry (DXR) is an effective and sensitive modality for monitoring periarticular osteoporosis, which is among the earliest features of rheumatoid arthritis, preceding bone erosions. DXR is a promising technique, which can provide quantitative data that allow early diagnosis. During the course of rheumatoid arthritis it can be deployed in combination with established X-ray scoring methods to inform decisions regarding the optimal therapy to prevent joint destruction
Capacity of a bosonic memory channel with Gauss-Markov noise
We address the classical capacity of a quantum bosonic memory channel with
additive noise, subject to an input energy constraint. The memory is modeled by
correlated noise emerging from a Gauss-Markov process. Under reasonable
assumptions, we show that the optimal modulation results from a "quantum
water-filling" solution above a certain input energy threshold, similar to the
optimal modulation for parallel classical Gaussian channels. We also derive
analytically the optimal multimode input state above this threshold, which
enables us to compute the capacity of this memory channel in the limit of an
infinite number of modes. The method can also be applied to a more general
noise environment which is constructed by a stationary Gauss process. The
extension of our results to the case of broadband bosonic channels with colored
Gaussian noise should also be straightforward.Comment: 11 pages, 4 figures, final corrections mad
External iliac artery thrombosis associated with the ilio-inguinal approach in the management of acetabular fractures: a case report
<p>Abstract</p> <p>Introduction</p> <p>The ilio-inguinal approach has come to be used routinely in the management of acetabular fractures involving the anterior wall. Thrombotic complications following surgery via this route are a serious, but rare, complication.</p> <p>Case presentation</p> <p>We report the case of a 66-year-old male patient who slipped on an icy pavement and fell on his left hip. He sustained a comminuted acetabular fracture (a transtectal T-fracture with an incomplete posterior stem through the ischial tuberosity), and was operated on five days later, via an ilio-inguinal approach. In the recovery room, his left lower limb was found to be cool and pale. Immediate re-exploration showed a left external iliac artery thrombosis, and thrombectomy was performed. In the surgical management of acetabular fractures, thrombosis of a major pelvic artery is a rare but potentially devastating complication. We discuss the possible aetiology (initial vessel trauma versus iatrogenic, intraoperative arterial injury) and pathomechanism, and wish to draw attention to this complication and to recommend ways in which it can be prevented.</p> <p>Conclusion</p> <p>We recommend circulation monitoring in patients with acetabular fractures, especially where nerve blocks and/or deep sedation/analgesia have been used. High-risk patients should be identified and subjected to intensive preoperative screening, including ultrasonography and if necessary angiography.</p
On the proper reconstruction of complex dynamical systems spoilt by strong measurement noise
This article reports on a new approach to properly analyze time series of
dynamical systems which are spoilt by the simultaneous presence of dynamical
noise and measurement noise. It is shown that even strong external measurement
noise as well as dynamical noise which is an intrinsic part of the dynamical
process can be quantified correctly, solely on the basis of measured times
series and proper data analysis. Finally real world data sets are presented
pointing out the relevance of the new approach
Computational Fluid Dynamic Investigations on a Small-Scale Liquid Sodium Loop
Liquid metal heat transfer systems are a technically attractive option to increase the efficiency of CSP plants. Sodium as heat transfer medium is promising especially due to high heat transfer rates. In this paper, basic considerations are made to match the requirements of a small-scale loop with sodium as heat transfer medium. The setup of the test facility KArlsruhe ReceIver test FAcility (KARIFA) to heat up this loop with a 20 kW IR laser is described. The loop is planned as an integrated design using an additive manufacturing process. Different technologies like selective laser melting (SLM) are established processes to realize an integrated design and to bring together components in one part. Some variations must be implemented to adapt these processes to liquid metal loops. The high heat fluxes also demand a flow simulation to ensure an efficient and safe operation. A Reynolds-averaged Navier-Stokes (RANS) steady state simulation was performed to show the surface and duct temperatures as well as dimensionless values to analyse the characteristics of the sodium flow
Cyanine Dye Coupling Mediates Self-assembly of a pH Sensitive Peptide into Novel 3D Architectures
Synthetic multichromophore systems are of great importance in artificial light harvesting devices, organic optoelectronics, tumor imaging and therapy. Here, we introduce a promising strategy for the construction of self-assembled peptide templated dye stacks based on coupling of a de novo designed pH sensitive peptide with a cyanine dye Cy5 at its N-terminus. Microscopic techniques, in particular cryogenic TEM (cryo-TEM) and cryo-electron tomography technique (cryo-ET), reveal two types of highly ordered three-dimensional assembly structures on the micrometer scale. Unbranched compact layered rods are observed at pH 7.4 and two-dimensional membrane-like assemblies at pH 3.4, both species displaying spectral features of H-aggregates. Molecular dynamics simulations reveal that the coupling of Cy5 moieties promotes the formation of both ultrastructures, whereas the protonation states of acidic and basic amino acid side chains dictates their ultimate three-dimensional organization
Multiwavelength Observations of LS I +61 303 with VERITAS, Swift and RXTE
We present results from a long-term monitoring campaign on the TeV binary LSI
+61 303 with VERITAS at energies above 500 GeV, and in the 2-10 keV hard X-ray
bands with RXTE and Swift, sampling nine 26.5 day orbital cycles between
September 2006 and February 2008. The binary was observed by VERITAS to be
variable, with all integrated observations resulting in a detection at the 8.8
sigma (2006/2007) and 7.3 sigma (2007/2008) significance level for emission
above 500 GeV. The source was detected during active periods with flux values
ranging from 5 to 20% of the Crab Nebula, varying over the course of a single
orbital cycle. Additionally, the observations conducted in the 2007-2008
observing season show marginal evidence (at the 3.6 sigma significance level)
for TeV emission outside of the apastron passage of the compact object around
the Be star. Contemporaneous hard X-ray observations with RXTE and Swift show
large variability with flux values typically varying between 0.5 and 3.0*10^-11
ergs cm^-2 s^-1 over a single orbital cycle. The contemporaneous X-ray and TeV
data are examined and it is shown that the TeV sampling is not dense enough to
detect a correlation between the two bands.Comment: 30 pages, 5 figures, 2 table, Accepted for publication in The
Astrophysical Journa
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