525 research outputs found
Interaction between nitric oxide signaling and gap junctions: Effects on vascular function
Nitric oxide signaling, through eNOS (or possibly nNOS), and gap junction communication are essential for normal vascular function. While each component controls specific aspects of vascular function, there is substantial evidence for cross-talk between nitric oxide signaling and the gap junction proteins (connexins), and more recently, protein protein association between eNOS and connexins. This review will examine the evidence for interaction between these pathways in normal and diseased arteries, highlight the questions that remain about the mechanisms of their interaction, and explore the possible interaction between nitric oxide signaling and the newly discovered pannexin channels. This article is part of a Special Issue entitled: The Communicating junctions, composition, structure and characteristics. (C) 2011 Elsevier B.V. All rights reserved
Stark Effect of Interactive Electron-hole pairs in Spherical Semiconductor Quantum Dots
We present a theoretical variational approach, based on the effective mass
approximation (EMA), to study the quantum-confinement Stark effects for
spherical semiconducting quantum dots in the strong confinement regime of
interactive electron-hole pair and limiting weak electric field. The respective
roles of the Coulomb potential and the polarization energy are investigated in
details. Under reasonable physical assumptions, analytical calculations can be
performed. They clearly indicate that the Stark shift is a quadratic function
of the electric field amplitude in the regime of study. The resulting numerical
values are found to be in good agreement with experimental data over a
significant domain of validity
Contribution to the understanding of tribological properties of graphite intercalation compounds with metal chloride
Intrinsic tribological properties of lamellar compounds are usually attributed to the presence of van der Waals gaps in their structure through which interlayer interactions are weak. The controlled variation of the distances and interactions between graphene layers by intercalation of electrophilic species in graphite is used in order to explore more deeply the friction reduction properties of low-dimensional compounds. Three graphite intercalation compounds with antimony pentachloride, iron trichloride and aluminium trichloride are studied. Their tribological properties are correlated to their structural parameters, and the interlayer interactions are deduced from ab initio bands structure calculations
RESEAL II: a large-scale in situ demonstration for repository sealing in an argillaceous host rock: phase II
Final ReportPreprin
Spatially-resolved decoherence of donor spins in silicon strained by a metallic electrode
Electron spins are amongst the most coherent solid-state systems known,
however, to be used in devices for quantum sensing and information processing
applications, they must be typically placed near interfaces. Understanding and
mitigating the impacts of such interfaces on the coherence and spectral
properties of electron spins is critical to realize such applications, but is
also challenging: inferring such data from single-spin studies requires many
measurements to obtain meaningful results, while ensemble measurements
typically give averaged results that hide critical information. Here, we report
a comprehensive study of the coherence of near-surface bismuth donor spins in
28-silicon at millikelvin temperatures. In particular, we use strain-induced
frequency shifts caused by a metallic electrode to make spatial maps of spin
coherence as a function of depth and position relative to the electrode. By
measuring magnetic-field-insensitive clock transitions we separate magnetic
noise caused by surface spins from charge noise. Our results include
quantitative models of the strain-split spin resonance spectra and extraction
of paramagnetic impurity concentrations at the silicon surface. The interplay
of these decoherence mechanisms for such near-surface electron spins is
critical for their application in quantum technologies, while the combination
of the strain splitting and clock transition extends the coherence lifetimes by
up to two orders of magnitude, reaching up to 300 ms at a mean depth of only
100nm. The technique we introduce here to spatially map coherence in
near-surface ensembles is directly applicable to other spin systems of active
interest, such as defects in diamond, silicon carbide, and rare earth ions in
optical crystals.Comment: 16 pages, 11 figure
Circular dichroism in molecular-frame photoelectron angular distributions in the dissociative photoionization of H2 and D2 molecules
ABSTRACT: The presence of net circular dichroism in the photoionization of nonchiral homonuclear molecules has been put in evidence recently through the measurement of molecular-frame photoelectron angular distributions in
dissociative photoionization of H2 [Dowek et al., Phys. Rev. Lett. 104, 233003 (2010)]. In this work we present a detailed study of circular dichroism in the photoelectron angular distributions of H2 and D2 molecules, oriented perpendicularly to the propagation vector of the circularly polarized light, at different photon energies (20, 27, and 32.5 eV). Circular dichroism in the angular distributions at 20 and to a large extent 27 eV exhibits the usual pattern in which inversion symmetry is preserved. In contrast, at 32.5 eV, the inversion symmetry breaks down, which eventually leads to total circular dichroism after integration over the polar emission angle. Time-dependent ab initio calculations support and explain the observed results for H2 in terms of quantum interferences between direct photoionization and delayed autoionization from the Q1 and Q2 doubly excited states into ionic states (1sσg and 2pσu) of different inversion symmetry. Nevertheless, for D2 at 32.5 eV, there is a particular case where theory and experiment disagree in the magnitude of the symmetry breaking: when D+ ions are produced with an energy of around 5 eV. This reflects the subleties associated to such simple molecules when exposed to this fine scrutiny
Marriage “sharia style”: everyday practices of Islamic morality in England
The growing visibility of Islam in the public spaces of Western societies is often interpreted in the media as a sign of Muslim radicalisation. This article questions this postulate by examining the flourishing Muslim marriage industry in the UK. It argues that these ‘halal’ services, increasingly popular among the young generation of British Muslims, reflect the semantic shifting of categories away from the repertoire of Islamic jurisprudence to cultural and identity labels visible in public space. Informed by long-term ethnographic fieldwork in the British field of Islamic law, this article examines a Muslim speed-dating event, which took place in central London in 2013. It investigates how Islamic morality is maintained and negotiated in everyday social interactions rather than cultivated via discipline and the pursuit of virtuous dispositions. Using Goffman’s “frame analysis” and his interpretation of the social as a space of “performances” as well as recent anthropological reflections on “ordinary ethics” (Lambek) and “everyday Islam” (Schielke, Osella and Soares), it examines the potential for such practices to define the contours of a new public culture where difference is celebrated as a form of distinction
Speech, language, and reading in 10-year-olds with cleft: Associations with teasing, satisfaction with speech, and psychological adjustment
© 2017 American Cleft Palate-Craniofacial Association. Background: Despite the use of multidisciplinary services, little research has addressed issues involved in the care of those with cleft lip and/or palate across disciplines. The aim was to investigate associations between speech, language, reading, and reports of teasing, subjective satisfaction with speech, and psychological adjustment. Design: Cross-sectional data collected during routine, multidisciplinary assessments in a centralized treatment setting, including speech and language therapists and clinical psychologists. Participants: Children with cleft with palatal involvement aged 10 years from three birth cohorts (N = 170) and their parents. Outcome Measures: Speech: SVANTE-N. Language: Language 6-16 (sentence recall, serial recall, vocabulary, and phonological awareness). Reading: Word Chain Test and Reading Comprehension Test. Psychological measures: Strengths and Difficulties Questionnaire and extracts from the Satisfaction With Appearance Scale and Child Experience Questionnaire. Results: Reading skills were associated with self- and parent-reported psychological adjustment in the child. Subjective satisfaction with speech was associated with psychological adjustment, while not being consistently associated with speech therapists' assessments. Parent-reported teasing was found to be associated with lower levels of reading skills. Having a medical and/or psychological condition in addition to the cleft was found to affect speech, language, and reading significantly. Conclusions: Cleft teams need to be aware of speech, language, and/or reading problems as potential indicators of psychological risk in children with cleft. This study highlights the importance of multiple reports (self, parent, and specialist) and a multidisciplinary approach to cleft care and research
Voriconazole and squamous cell carcinoma after lung transplantation: A multicenter study
This study evaluated the independent contribution of voriconazole to the development of squamous cell carcinoma (SCC) in lung transplant recipients, by attempting to account for important confounding factors, particularly immunosuppression. This international, multicenter, retrospective, cohort study included adult patients who underwent lung transplant during 2005-2008. Cox regression analysis was used to assess the effects of voriconazole and other azoles, analyzed as time-dependent variables, on the risk of developing biopsy-confirmed SCC. Nine hundred lung transplant recipients were included. Median follow-up time from transplant to end of follow-up was 3.51 years. In a Cox regression model, exposure to voriconazole alone (adjusted hazard ratio 2.39, 95% confidence interval 1.31-4.37) and exposure to voriconazole and other azole(s) (adjusted hazard ratio 3.45, 95% confidence interval 1.07-11.06) were associated with SCC compared with those unexposed after controlling for important confounders including immunosuppressants. Exposure to voriconazole was associated with increased risk of SCC of the skin in lung transplant recipients. Residual confounding could not be ruled out because of the use of proxy variables to control for some confounders. Benefits of voriconazole use when prescribed to lung transplant recipients should be carefully weighed versus the potential risk of SCC. This article is protected by copyright. All rights reserved
- …