5,739 research outputs found
Haemoglobin scavenging after subarachnoid haemorrhage
Rapid and effective clearance of cell-free haemoglobin after subarachnoid haemorrhage (SAH) is important to prevent vasospasm and neurotoxicity and improve long-term outcome. Haemoglobin is avidly bound by haptoglobin, and the complex is cleared by CD163 expressed on the membrane surface of macrophages. We studied the kinetics of haemoglobin and haptoglobin in cerebrospinal fluid after SAH. We show that haemoglobin levels rise gradually after SAH. Haptoglobin levels rise acutely with aneurysmal rupture as a result of injection of blood into the subarachnoid space. Although levels decline as haemoglobin scavenging occurs, complete depletion of haptoglobin does not occur and levels start rising again, indicating saturation of CD163 sites available for haptoglobin-haemoglobin clearance. In a preliminary neuropathological study we demonstrate that meningeal CD163 expression is upregulated after SAH, in keeping with a proinflammatory state. However, loss of CD163 occurs in meningeal areas with overlying blood compared with areas without overlying blood. Becauses ADAM17 is the enzyme responsible for shedding membrane-bound CD163, its inhibition may be a potential therapeutic strategy after SAH
Gas Purity effect on GEM Performance in He and Ne at Low Temperatures
The performance of Gas Electron Multipliers (GEMs) in gaseous He, Ne, He+H2
and Ne+H2 was studied at temperatures in the range of 3-293 K. This paper
reports on previously published measurements and additional studies on the
effects of the purity of the gases in which the GEM performance is evaluated.
In He, at temperatures between 77 and 293 K, triple-GEM structures operate at
rather high gains, exceeding 1000. There is an indication that this high gain
is achieved through the Penning effect as a result of impurities in the gas. At
lower temperatures the gain-voltage characteristics are significantly modified
probably due to the freeze-out of these impurities. Double-GEM and single-GEM
structures can operate down to 3 K at gains reaching only several tens at a gas
density of about 0.5 g/l; at higher densities the maximum gain drops further.
In Ne, the maximum gain also drops at cryogenic temperatures. The gain drop in
Ne at low temperatures can be re-established in Penning mixtures of Ne+H2: very
high gains, exceeding 104, have been obtained in these mixtures at 30-77 K, at
a density of 9.2 g/l which corresponds to saturated Ne vapor density at 27 K.
The addition of small amounts of H2 in He also re-establishes large GEM gains
above 30 K but no gain was observed in He+H2 at 4 K and a density of 1.7 g/l
(corresponding to roughly one-tenth of the saturated vapor density). These
studies are, in part, being pursued in the development of two-phase He and Ne
detectors for solar neutrino detection.Comment: 4 pages, 7 figure
Modeling pedestrian evacuation movement in a swaying ship
With the advance in living standard, cruise travel has been rapidly expanding
around the world in recent years. The transportation of passengers in water has
also made a rapid development. It is expected that ships will be more and more
widely used. Unfortunately, ship disasters occurred in these years caused
serious losses. It raised the concern on effectiveness of passenger evacuation
on ships. The present study thus focuses on pedestrian evacuation features on
ships. On ships, passenger movements are affected by the periodical water
motion and thus are quite different from the characteristic when walking on
static horizontal floor. Taking into consideration of this special feature, an
agent-based pedestrian model is formulized and the effect of ship swaying on
pedestrian evacuation efficiency is investigated. Results indicated that the
proposed model can be used to quantify the special evacuation process on ships.Comment: Traffic and Granular Flow'15, At Delft, the Netherland
The impact of security bollards on evacuation flow
Individual bollard and bollard arrays (BA) have become a common design of Vehicle Security Barriers surrounding crowded spaces, in particular busy rail and underground stations, airports and many key commercial and public buildings. While guidance on the general installation of BA is available this earlier advice did not take into consideration the potential impact a BA may have on pedestrian flow during emergency evacuation. To address this issue, FSEG in collaboration with the CPNI and DfT investigated the potential impact that security bollards may have on evacuation flows through a series of full-scale experiments. In total 50 trials were conducted over three days on two weekends in March 2013. The experiment for each unique trial set up was repeated three times in order to ensure that the collected data was repeatable and representative of the trial conditions. The trials took place in the Queen Anne Courtyard of the University of Greenwich. Some 630 participants were recruited to take part in the trials, of which 458 actually participated. The trials were designed to capture the conditions produced as the population left a simulated station exit: at the point of exit (Exit flow trials) and when this population is incident upon the BA (BA flow trials). These trials were designed to control a number of key parameters in order to explore two specific questions: How does BA stand-off distance impact exit flow? And how does the BA impact flow passing through the BA? A key finding from these trials is that if the BA stand-off distance is greater than 3m there is not expected to be any adverse impact on exit flow due to the presence of the BA. However, it is essential that the BA is sufficiently wide so that it does not restrict the natural diffusion of the crowd as it exits
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The Role of Genes in Defining a Molecular Biology of PTSD
Because environmental exposure to trauma is the sine qua non for the development of Post Traumatic Stress Disorder (PTSD), the recent focus on genetic studies has been noteworthy. The main catalyst for such studies is the observation from epidemiological studies that not all trauma survivors develop this disorder. Furthermore, neuroendocrine findings suggest pre-existing hormonal alterations that confer risk for PTSD. This paper presents the rationale for examining genetic factors in PTSD and trauma exposure, but suggests that studies of genotype may only present a limited picture of the molecular biology of this disorder. We describe the type of information that can be obtained from candidate gene and genomic studies that incorporate environmental factors in the design (i.e., gene – environment interaction and gene-environment correlation studies) and studies that capitalize on the idea that environment modifies gene expression, via epigenetic or other molecular mechanisms. The examination of epigenetic mechanisms in tandem with gene expression will help refine models that explain how PTSD risk, pathophysiology, and recovery is mediated by the environment. Since inherited genetic variation may also influence the extent of epigenetic or gene expression changes resulting from the environment, such studies should optimally be followed up by studies of genotype
Active dynamic signage system: A full-scale evacuation trial
Efficient evacuation from transport terminals in an emergency can be constrained by the complex nature of the buildings. Although emergency signage systems are widely used as a well established means of facilitating evacuation, recent research demonstrates that only 38% of people 'see' conventional static emergency signage in simulated emergency situations. Besides, conventional signage only conveys single and passive information; therefore, they cannot be adapted to respond to developing evacuation situations. The EU FP7 GETWAY project addresses this problem for transport terminals through the development of an Intelligent Active Dynamic Signage System (IADSS), which routes terminal passengers to their optimal exit according to the distribution of occupants and the nature of the evolving incident. This paper presents the results of two full scale evacuation trials conducted in a rail station to establish the specific benefits of the Active Dynamic Signage System (i.e. ADSS, a subsystem of the IADSS without the intelligent component) over the current standard emergency signage system. These trials demonstrate that the flashing lights of the ADSS do have a greater effect on route choice compared to the standard signage system and therefore are more likely to promote the adoption of emergency evacuation procedures than would otherwise be the case, especially where evacuees are required to adopt routes not entirely based on proximity
Searching for Dark Matter at the LHC with a Mono-Z
We investigate a mono-Z process as a potential dark matter search strategy at
the LHC. In this channel a single Z boson recoils against missing transverse
momentum, attributed to dark matter particles, , which escape the
detector. This search strategy is related, and complementary to, monojet and
monophoton searches. For illustrative purposes we consider the process
in a toy dark matter model, where the Z boson is
emitted from either the initial state quarks, or from the internal propagator.
Among the signatures of this process will be a pair of muons with high pT that
reconstruct to the invariant mass of the Z, and large amounts of missing
transverse energy. Being a purely electroweak signal, QCD and other Standard
Model backgrounds are relatively easily removed with modest selection cuts. We
compare the signal to Standard Model backgrounds and demonstrate that, even for
conservative cuts, there exist regions of parameter space where the signal may
be clearly visible above background in future LHC data, allowing either new
discovery potential or the possibility of supplementing information about the
dark sector beyond that available from other observable channels.Comment: 11 pages, 13 figure
Data-Intensive architecture for scientific knowledge discovery
This paper presents a data-intensive architecture that demonstrates the ability to support applications from a wide range of application domains, and support the different types of users involved in defining, designing and executing data-intensive processing tasks. The prototype architecture is introduced, and the pivotal role of DISPEL as a canonical language is explained. The architecture promotes the exploration and exploitation of distributed and heterogeneous data and spans the complete knowledge discovery process, from data preparation, to analysis, to evaluation and reiteration. The architecture evaluation included large-scale applications from astronomy, cosmology, hydrology, functional genetics, imaging processing and seismology
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