2,391 research outputs found
Development and Evaluation of Elastomeric Materials for Geothermal Applications
A material was formulated having about 250-350 psi tensile strength and 30-80 percent elongation at 260 C for at least 24 hours in simulated brine. The relationship between these laboratory test results and sealing performance in actual or simulated test conditions is not entirely clear; however, it is believed that no conventional formation or casing packer design is likely to perform well using these materials. The synthetic effort focused on high temperature block copolymers and development of curable polystyrene. Procedures were worked out for synthesizing these new materials. Initial results with heat-cured unfilled polystyrene 'gum' at 260 C indicate a tensile strength of about 50 psi. Cast films of the first sample of polyphenyl quinoxaline-polystyrene block copolymer, which has 'graft-block' structure consisting of a polystyrene chain with pendant polyphenyl quinoxaline groups, show elastomeric behavior in the required temperature range. Its tensile strength and elongation at 260 C were 220-350 psi and 18-36 percent, respectively. All of these materials also showed satisfactory hydrolytic stability
Compassionate containment? Balancing technical safety and therapy in the design of psychiatric wards
This paper contributes to the international literature examining design of inpatient settings for mental health care. Theoretically, it elaborates the connections between conceptual frameworks from different strands of literature relating to therapeutic landscapes, social control and the social construction of risk. It does so through a discussion of the substantive example of research to evaluate the design of a purpose built inpatient psychiatric health care facility, opened in 2010 as part of the National Health Service (NHS) in England. Findings are reported from interviews or discussion groups with staff, patients and their family and friends. This paper demonstrates a strong, and often critical awareness among members of staff and other participants about how responsibilities for risk governance of ‘persons’ are exercised through ‘technical safety’ measures and the implications for therapeutic settings. Our participants often emphasised how responsibility for technical safety was being invested in the physical infrastructure of certain ‘places’ within the hospital where risks are seen to be ‘located’. This illuminates how the spatial dimensions of social constructions of risk are incorporated into understandings about therapeutic landscapes. There were also more subtle implications, partly relating to ‘Panopticist’ theories about how the institution uses technical safety to supervise its own mechanisms, through the observation of staff behaviour as well as patients and visitors. Furthermore, staff seemed to feel that in relying on technical safety measures they were, to a degree, divesting themselves of human responsibility for risks they are required to manage. However, their critical assessment showed their concerns about how this might conflict with a more therapeutic approach and they contemplated ways that they might be able to engage more effectively with patients without the imposition of technical safety measures. These findings advance our thinking about the construction of therapeutic landscapes in theory and in practice
Effects of precompetition state anxiety interventions on performance time and accuracy among amateur soccer players: Revisiting the matching hypothesis
In this study, we tested the matching ypothesis, which contends that administration of a cognitive or somatic anxiety intervention should be matched to a participant's dominant anxiety response. Sixty-one male soccer players (mean age 31.6 years, s=6.3) were assigned to one of four groups based on their responses to the Competitive State Anxiety Inventory-2, which was modified to include a directional scale. Interventions were randomly administered in a counterbalanced order 10 min before each performance trial on a soccer skill test. The dominantly cognitive anxious group (n=17), the dominantly somatic anxious group (n=17), and the non-anxious control intervention group (n=14) completed a baseline performance trial. The second and third trials were completed with random administration of brief cognitive and somatic interventions. The non-anxious control group (n=13) completed three trials with no intervention. A mixed-model, GroupTreatment multivariate analysis of variance indicated significant (P0.05), or performance time or accuracy (P>0.05). The present findings do not provide support for the matching hypothesis for state anxiety intensity and direction, or for performance
Channeling and Volume Reflection Based Crystal Collimation of Tevatron Circulating Beam Halo (T-980)
The T980 crystal collimation experiment is underway at the Tevatron to
determine if this technique could increase 980 GeV beam-halo collimation
efficiency at high-energy hadron colliders such as the Tevatron and the LHC.
T980 also studies various crystal types and parameters. The setup has been
substantially enhanced during the Summer 2009 shutdown by installing a new
O-shaped crystal in the horizontal goniometer, as well as adding a vertical
goniometer with two alternating crystals (O-shaped and multi-strip) and
additional beam diagnostics. First measurements with the new system are quite
encouraging, with channeled and volume-reflected beams observed on the
secondary collimators as predicted. Investigation of crystal collimation
efficiencies with crystals in volume reflection and channeling modes are
described in comparison with an amorphous primary collimator. Results on the
system performance are presented for the end-of-store studies and for entire
collider stores. The first investigation of colliding beam collimation
simultaneously using crystals in both the vertical and horizontal plane has
been made in the regime with horizontally channeled and vertically
volume-reflected beams. Planning is underway for significant hardware
improvements during the FY10 summer shutdown and for dedicated studies during
the final year of Tevatron operation and also for a "post-collider beam physics
running" period.Comment: 3 pp. 1st International Particle Accelerator Conference: IPAC'10,
23-28 May 2010: Kyoto, Japa
Idarucizumab for Dabigatran Reversal - Full Cohort Analysis.
BACKGROUND: Idarucizumab, a monoclonal antibody fragment, was developed to reverse the anticoagulant effect of dabigatran.
METHODS: We performed a multicenter, prospective, open-label study to determine whether 5 g of intravenous idarucizumab would be able to reverse the anticoagulant effect of dabigatran in patients who had uncontrolled bleeding (group A) or were about to undergo an urgent procedure (group B). The primary end point was the maximum percentage reversal of the anticoagulant effect of dabigatran within 4 hours after the administration of idarucizumab, on the basis of the diluted thrombin time or ecarin clotting time. Secondary end points included the restoration of hemostasis and safety measures.
RESULTS: A total of 503 patients were enrolled: 301 in group A, and 202 in group B. The median maximum percentage reversal of dabigatran was 100% (95% confidence interval, 100 to 100), on the basis of either the diluted thrombin time or the ecarin clotting time. In group A, 137 patients (45.5%) presented with gastrointestinal bleeding and 98 (32.6%) presented with intracranial hemorrhage; among the patients who could be assessed, the median time to the cessation of bleeding was 2.5 hours. In group B, the median time to the initiation of the intended procedure was 1.6 hours; periprocedural hemostasis was assessed as normal in 93.4% of the patients, mildly abnormal in 5.1%, and moderately abnormal in 1.5%. At 90 days, thrombotic events had occurred in 6.3% of the patients in group A and in 7.4% in group B, and the mortality rate was 18.8% and 18.9%, respectively. There were no serious adverse safety signals.
CONCLUSIONS: In emergency situations, idarucizumab rapidly, durably, and safely reversed the anticoagulant effect of dabigatran. (Funded by Boehringer Ingelheim; RE-VERSE AD ClinicalTrials.gov number, NCT02104947 .)
Dynamical steady states in driven quantum systems
We derive dynamical equations for a driven, dissipative quantum system in which the environment-induced relaxation rate is comparable to the Rabi frequency, avoiding assumptions on the frequency dependence of the environmental coupling. When the environmental coupling varies significantly on the scale of the Rabi frequency, secular or rotating wave approximations break down. We avoid these approximations, yielding dynamical steady states which account for the interaction between driven quantum dots and their phonon environment. The theory, which is motivated by recent experimental observations, qualitatively and quantitatively describes the transition from asymmetric unsaturated resonances at weak driving to population inversion at strong driving
Different expressions of the same mode: a recent dialogue between archaeological and contemporary drawing practices
In this article we explore what we perceive as pertinent features of shared experience at the excavations of an Iron Age Hillfort at Bodfari, North Wales, referencing artist, archaeologist and examples of seminal art works and archaeological records resulting through inter-disciplinary collaboration. We explore ways along which archaeological and artistic practices of improvisation become entangled and productive through their different modes of mark-making. We contend that marks and memories of artist and archaeologist alike emerge interactively, through the mutually constituting effects of the object of study, the tools of exploration, and the practitioners themselves, when they are enmeshed in the cross-modally bound activities. These include, but are not limited to, remote sensing, surveying, mattocking, trowelling, drawing, photographing, videoing and sound recording. These marks represent the co-signatories: the gesture of the often anonymous practitioners, the voice of the deposits, as well as the imprint of the tools, and their interplay creates a multi-threaded narrative documenting their modes of intra-action, in short our practices. They occupy the conceptual space of paradata, and in the process of saturating the interstices of digital cognitive prosthetics they lend probity to their translations in both art form and archive
Extreme sensitivity of the spin-splitting and 0.7 anomaly to confining potential in one-dimensional nanoelectronic devices
Quantum point contacts (QPCs) have shown promise as nanoscale spin-selective
components for spintronic applications and are of fundamental interest in the
study of electron many-body effects such as the 0.7 x 2e^2/h anomaly. We report
on the dependence of the 1D Lande g-factor g* and 0.7 anomaly on electron
density and confinement in QPCs with two different top-gate architectures. We
obtain g* values up to 2.8 for the lowest 1D subband, significantly exceeding
previous in-plane g-factor values in AlGaAs/GaAs QPCs, and approaching that in
InGaAs/InP QPCs. We show that g* is highly sensitive to confinement potential,
particularly for the lowest 1D subband. This suggests careful management of the
QPC's confinement potential may enable the high g* desirable for spintronic
applications without resorting to narrow-gap materials such as InAs or InSb.
The 0.7 anomaly and zero-bias peak are also highly sensitive to confining
potential, explaining the conflicting density dependencies of the 0.7 anomaly
in the literature.Comment: 23 pages, 7 figure
Recombinant ADAMTS13 reduces abnormally up-regulated von Willebrand factor in plasma from patients with severe COVID-19
Thrombosis affecting the pulmonary and systemic vasculature is common during severe COVID-19 and causes adverse outcomes. Although thrombosis likely results from inflammatory activation of vascular cells, the mediators of thrombosis remain unconfirmed. In a cross-sectional cohort of 36 severe COVID-19 patients, we show that markedly increased plasma von Willebrand factor (VWF) levels were accompanied by a partial reduction in the VWF regulatory protease ADAMTS13. In all patients we find this VWF/ADAMTS13 imbalance to be associated with persistence of ultra-high-molecular-weight (UHMW) VWF multimers that are highly thrombogenic in some disease settings. Incubation of plasma samples from patients with severe COVID-19 with recombinant ADAMTS13 (rADAMTS13) substantially reduced the abnormally high VWF activity, reduced overall multimer size and depleted UHMW VWF multimers in a time and concentration dependent manner. Our data implicate disruption of normal VWF/ADAMTS13 homeostasis in the pathogenesis of severe COVID-19 and indicate that this can be reversed ex vivo by correction of low plasma ADAMTS13 levels. These findings suggest a potential therapeutic role for rADAMTS13 in helping restore haemostatic balance in COVID-19 patients
Antimicrobial use in European acute care hospitals: results from the second point prevalence survey (PPS) of healthcare-associated infections and antimicrobial use, 2016 to 2017
Antimicrobial agents used to treat infections are life-saving. Overuse may result in more frequent adverse effects and emergence of multidrug-resistant microorganisms. In 2016-17, we performed the second point-prevalence survey (PPS) of healthcare-associated infections (HAIs) and antimicrobial use in European acute care hospitals. We included 1,209 hospitals and 310,755 patients in 28 of 31 European Union/European Economic Area (EU/EEA) countries. The weighted prevalence of antimicrobial use in the EU/EEA was 30.5% (95% CI: 29.2-31.9%). The most common indication for prescribing antimicrobials was treatment of a community-acquired infection, followed by treatment of HAI and surgical prophylaxis. Over half (54.2%) of antimicrobials for surgical prophylaxis were prescribed for more than 1 day. The most common infections treated by antimicrobials were respiratory tract infections and the most commonly prescribed antimicrobial agents were penicillins with beta-lactamase inhibitors. There was wide variation of patients on antimicrobials, in the selection of antimicrobial agents and in antimicrobial stewardship resources and activities across the participating countries. The results of the PPS provide detailed information on antimicrobial use in European acute care hospitals, enable comparisons between countries and hospitals, and highlight key areas for national and European action that will support efforts towards prudent use of antimicrobials
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