172 research outputs found
Structural and thermodynamic properties of heavily mechanically deformed Ru and AlRu
We report on high-energy ball milling of Ru and AlRu. The deformation results in a drastic decrease of the crystal size to a nanometer scale and in an increase of atomic-level strain. This is accompanied by a disordering of the crystal lattice as is shown by means of the long-range-order parameter in AlRu. The specific heat increases by more than 15%–20%, indicating large changes in the vibrational and configurational part of the entropy. The stored energy of cold work is up to 6 kJ/mol for AlRu and 10 kJ/mol for Ru. This is almost 40% of the heat of fusion of Ru and exceeds by far the energies stored by other deformation processes
Endovascular Treatment of Intracranial Vein and Venous Sinus Thrombosis-A Systematic Review.
BACKGROUND
Cerebral venous sinus or vein thromboses (SVT) are treated with heparin followed by oral anticoagulation. Even after receiving the best medical treatment, numerous patients experience neurological deterioration, intracerebral hemorrhage or brain edema. Debate regarding whether endovascular treatment (EVT) is beneficial in such severe cases remains ongoing. This systematic review summarizes the current evidence supporting the use of EVT for SVT on the basis of case presentations, with a focus on patient selection, treatment strategies and the effects of the COVID-19 pandemic.
METHODS
This systemic literature review included randomized controlled trials (RCTs) and retrospective observational data analyzing five or more patients. Follow-up information (modified Rankin scale (mRS)) was required to be provided (individual patient data).
RESULTS
21 records (n = 405 patients; 1 RCT, 20 observational studies) were identified. EVT was found to be feasible and safe in a highly selected patient cohort but was not associated with an increase in good functional outcomes (mRS 0-2) in RCT data. In observational data, good functional outcomes were frequently observed despite an anticipated poor prognosis.
CONCLUSION
The current evidence does not support the routine incorporation of EVT in SVT treatment. However, in a patient cohort prone to poor prognosis, EVT might be a reasonable therapeutic option. Further studies determining the patients at risk, choice of methods and devices, and timing of treatment initiation are warranted
Mesons in a Poincare Covariant Bethe-Salpeter Approach
We develop a covariant approach to describe the low-lying scalar,
pseudoscalar, vector and axialvector mesons as quark-antiquark bound states.
This approach is based on an effective interaction modeling of the
non--perturbative structure of the gluon propagator that enters the quark
Schwinger-Dyson and meson Bethe-Salpeter equations. We consistently treat these
integral equations by precisely implementing the quark propagator functions
that solve the Schwinger-Dyson equations into the Bethe-Salpeter equations in
the relevant kinematical region. We extract the meson masses and compute the
pion and kaon decay constants. We obtain a quantitatively correct description
for pions, kaons and vector mesons while the calculated spectra of scalar and
axialvector mesons suggest that their structure is more complex than being
quark-antiquark bound states.Comment: 18 pages LaTeX, 5 figures; some changes in the presentation, new
results on axial vector mesons in enlarged mixing scheme; version to be
published in Physical Review
The politicisation of evaluation: constructing and contesting EU policy performance
Although systematic policy evaluation has been conducted for decades and has been growing strongly within the European Union (EU) institutions and in the member states, it remains largely underexplored in political science literatures. Extant work in political science and public policy typically focuses on elements such as agenda setting, policy shaping, decision making, or implementation rather than evaluation. Although individual pieces of research on evaluation in the EU have started to emerge, most often regarding policy “effectiveness” (one criterion among many in evaluation), a more structured approach is currently missing. This special issue aims to address this gap in political science by focusing on four key focal points: evaluation institutions (including rules and cultures), evaluation actors and interests (including competencies, power, roles and tasks), evaluation design (including research methods and theories, and their impact on policy design and legislation), and finally, evaluation purpose and use (including the relationships between discourse and scientific evidence, political attitudes and strategic use). The special issue considers how each of these elements contributes to an evolving governance system in the EU, where evaluation is playing an increasingly important role in decision making
K -> pi pi and a light scalar meson
We explore the Delta-I= 1/2 rule and epsilon'/epsilon in K -> pi pi
transitions using a Dyson-Schwinger equation model. Exploiting the feature that
QCD penguin operators direct K^0_S transitions through 0^{++} intermediate
states, we find an explanation of the enhancement of I=0 K -> pi pi transitions
in the contribution of a light sigma-meson. This mechanism also affects
epsilon'/epsilon.Comment: 7 pages, REVTE
Cigarette smoke induces genetic instability in airway epithelial cells by suppressing FANCD2 expression
Chromosomal abnormalities are commonly found in bronchogenic carcinoma cells, but the molecular causes of chromosomal instability (CIN) and their relationship to cigarette smoke has not been defined. Because the Fanconi anaemia (FA)/BRCA pathway is essential for maintenance of chromosomal stability, we tested the hypothesis that cigarette smoke suppresses that activity of this pathway. Here, we show that cigarette smoke condensate (CSC) inhibited translation of FANCD2 mRNA (but not FANCC or FANCG) in normal airway epithelial cells and that this suppression of FANCD2 expression was sufficient to induce both genetic instability and programmed cell death in the exposed cell population. Cigarette smoke condensate also suppressed FANCD2 function and induced CIN in bronchogenic carcinoma cells, but these cells were resistant to CSC-induced apoptosis relative to normal airway epithelial cells. We, therefore, suggest that CSC exerts pressure on airway epithelial cells that results in selection and emergence of genetically unstable somatic mutant clones that may have lost the capacity to effectively execute an apoptotic programme. Carcinogen-mediated suppression of FANCD2 gene expression provides a plausible molecular mechanism for CIN in bronchogenic carcinogenesis
Conformal and continuous deposition of bifunctional cobalt phosphide layers on p-silicon nanowire arrays for improved solar hydrogen evolution
Vertically aligned p-silicon nanowire (SiNW) arrays have been extensively investigated in recent years as promising photocathodes for solar-driven hydrogen evolution. However, the fabrication of SiNW photocathodes with both high photoelectrocatalytic activity and long-term operational stability using a simple and affordable approach is a challenging task. Herein, we report conformal and continuous deposition of a di-cobalt phosphide (Co2P) layer on lithography-patterned highly ordered SiNW arrays via a cost-effective drop-casting method followed by a low-temperature phosphorization treatment. The as-deposited Co2P layer consists of crystalline nanoparticles and has an intimate contact with SiNWs, forming a well-defined SiNW@Co2P core/shell nanostructure. The conformal and continuous Co2P layer functions as a highly efficient catalyst capable of substantially improving the photoelectrocatalytic activity for the hydrogen evolution reaction (HER) and effectively passivates the SiNWs to protect them from photo-oxidation, thus prolonging the lifetime of the electrode. As a consequence, the SiNW@Co2P photocathode with an optimized Co2P layer thickness exhibits a high photocurrent density of -21.9 mA.cm(-2) at 0 V versus reversible hydrogen electrode and excellent operational stability up to 20 h for solar-driven hydrogen evolution, outperforming many nanostructured silicon photocathodes reported in the literature. The combination of passivation and catalytic functions in a single continuous layer represents a promising strategy for designing high-performance semiconductor photoelectrodes for use in solar-driven water splitting, which may simplify fabrication procedures and potentially reduce production costsThis work was funded by ERDF funds through the Portuguese Operational Programme for Competitiveness and Internationalization COMPETE 2020, and national funds through FCT – The Portuguese Foundation for Science and Technology, under the project “PTDC/CTM-ENE/2349/2014” (Grant Agreement No. 016660). The work is also partially funded by the Portugal-China Bilateral Collaborative Programme (FCT/21102/28/12/2016/S). L. F. Liu acknowledges the financial support of the FCT Investigator Grant (IF/01595/2014) and Exploratory Grant (IF/01595/2014/CP1247/CT0001). L. Qiao acknowledges the financial support of the Ministry of Science and Technology of China (Grant Agreement No. 2016YFE0132400).info:eu-repo/semantics/publishedVersio
Transfusion-transmitted infections
Although the risk of transfusion-transmitted infections today is lower than ever, the supply of safe blood products remains subject to contamination with known and yet to be identified human pathogens. Only continuous improvement and implementation of donor selection, sensitive screening tests and effective inactivation procedures can ensure the elimination, or at least reduction, of the risk of acquiring transfusion transmitted infections. In addition, ongoing education and up-to-date information regarding infectious agents that are potentially transmitted via blood components is necessary to promote the reporting of adverse events, an important component of transfusion transmitted disease surveillance. Thus, the collaboration of all parties involved in transfusion medicine, including national haemovigilance systems, is crucial for protecting a secure blood product supply from known and emerging blood-borne pathogens
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