2,154 research outputs found

    Biologic effects of oil fly ash.

    Get PDF
    Epidemiologic studies have demonstrated increased human morbidity and mortality with elevations in the concentration of ambient air particulate matter (PM). Fugitive fly ash from the combustion of oil and residual fuel oil significantly contributes to the ambient air particle burden. Residual oil fly ash (ROFA) is remarkable in the capacity to provoke injury in experimental systems. The unique composition of this emission source particle makes it particularly useful as a surrogate for ambient air PM in studies of biologic effects testing the hypothesis that metals mediate the biologic effects of air pollution particles. A majority of the in vitro and animal model investigations support the postulate that transition metals present in ROFA (especially vanadium) participate in Fenton-like chemical reactions to produce reactive oxygen species. This is associated with tyrosine phosphorylation, nuclear factor kappa B and other transcription factor activation, induction of inflammatory mediator expression, and inflammatory lung injury. It is also evident that vanadium accounts for a significant portion of the biologic activity of ROFA. The extrapolation of this body of investigation on ROFA to the field of ambient air PM is difficult, as particles in numerous environments have such small amounts of vanadium

    ‘It's like the bad guy in a movie who just doesn't die’ : a qualitative exploration of young people's adaptation to eczema and implications for self‐care

    Get PDF
    Background Eczema is a common childhood inflammatory skin condition, affecting more than one in five children. A popular perception is that children ‘outgrow eczema’, although epidemiological studies have shown that, for many, eczema follows a lifelong episodic course. Objectives To explore the perceptions of young people about the nature of their eczema and how these perceptions relate to their self‐care and adapting to living with eczema. Methods This is a secondary inductive thematic analysis of interviews conducted for Healthtalk.org. In total 23 interviews with young people with eczema were included. Of the 23 participants, 17 were female and six male, ranging from 17 to 25 years old. Results Participants generally experienced eczema as an episodic long‐term condition and reported a mismatch between information received about eczema and their experiences. The experience of eczema as long term and episodic had implications for self‐care, challenging the process of identifying triggers of eczema flare‐ups and evaluating the success of treatment regimens. Participants’ experiences of eczema over time also had implications for adaptation and finding a balance between accepting eczema as long term and hoping it would go away. This linked to a gradual shift in treatment expectations from ‘cure’ to ‘control’ of eczema. Conclusions For young people who continue to experience eczema beyond childhood, a greater focus on self‐care for a long‐term condition may be helpful. Greater awareness of the impact of early messages around ‘growing out of’ eczema and provision of high‐quality information may help patients to manage expectations and support adaptation to treatment regimens

    The GRAAL high resolution BGO calorimeter and its energy calibration and monitoring system

    Get PDF
    We describe the electromagnetic calorimeter built for the GRAAL apparatus at the ESRF. Its monitoring system is presented in detail. Results from tests and the performance obtained during the first GRAAL experiments are given. The energy calibration accuracy and stability reached is a small fraction of the intrinsic detector resolution.Comment: 19 pages, 14 figures, submitted to Nuclear Instruments and Method

    Evidence for narrow resonant structures at W1.68W \approx 1.68 and W1.72W \approx 1.72 GeV in real Compton scattering off the proton

    Get PDF
    First measurement of the beam asymmetry Σ\Sigma for Compton scattering off the proton in the energy range Eγ=0.851.25E_{\gamma}=0.85 - 1.25 GeV is presented. The data reveals two narrow structures at Eγ=1.036E_{\gamma}= 1.036 and Eγ=1.119E_{\gamma}=1.119 GeV. They may signal narrow resonances with masses near 1.681.68 and 1.721.72 GeV, or they may be generated by the sub-threshold KΛK\Lambda and ωp\omega p production. Their decisive identification requires additional theoretical and experimental efforts.Comment: Published versio

    Deuteron photo-disintegration with polarised photons in the energy range 30 - 50 MeV

    Full text link
    The reaction d(\vec\gamma,np) has been studied using the tagged and polarised LADON gamma ray beam at an energy 30 - 50 MeV to investigate the existence of narrow dibaryonic resonances recently suggested from the experimental measurements in a different laboratory. The beam was obtained by Compton back-scattering of laser light on the electrons of the storage ring ADONE. Photo-neutron yields were measured at five neutron angle \vartheta_n = 22, 55.5, 90, 125 and 157 degrees in the center of mass system.Our results do not support the existence of such resonances.Comment: 16 pages, Latex, 22 figures, 1 table. Nucl. Phys. A to appea

    Shedding New Light on Kaon-Nucleon/Nuclei Interaction and Its Astrophysical Implications with the AMADEUS Experiment at DAFNE

    Get PDF
    The AMADEUS experiment deals with the investigation of the low-energy kaon-nuclei hadronic interaction at the DA{\Phi}NE collider at LNF-INFN, which is fundamental to respond longstanding questions in the non-perturbative QCD strangeness sector. The antikaon-nucleon potential is investigated searching for signals from possible bound kaonic clusters, which would open the possibility for the formation of cold dense baryonic matter. The confirmation of this scenario may imply a fundamental role of strangeness in astrophysics. AMADEUS step 0 consisted in the reanalysis of 2004/2005 KLOE dataset, exploiting K- absorptions in H, 4He, 9Be and 12C in the setup materials. In this paper, together with a review on the multi-nucleon K- absorption and the particle identification procedure, the first results on the {\Sigma}0-p channel will be presented including a statistical analysis on the possible accomodation of a deeply bound stateComment: 6 pages, 2 figure, 1 table, HADRON 2015 conferenc

    Eta photoproduction off the neutron at GRAAL: Evidence for a resonant structure at W=1.67 GeV

    Full text link
    New (preliminary) data on eta photoproduction off the neutron are presented. These data reveal a resonant structure at W=1.67 GeV.Comment: 8 pages, 4 figures. Published in Proceedings of Workshop on the Physics of Excited Nucleons NSTAR2004, Grenoble, France, March 24 - 27, pg.19

    Unprecedented studies of the low-energy negatively charged kaons interactions in nuclear matter by AMADEUS

    Get PDF
    The AMADEUS experiment aims to provide unique quality data of KK^- hadronic interactions in light nuclear targets, in order to solve fundamental open questions in the non-perturbative strangeness QCD sector, like the controversial nature of the Λ(1405)\Lambda(1405) state, the yield of hyperon formation below threshold, the yield and shape of multi-nucleon KK^- absorption, processes which are intimately connected to the possible existence of exotic antikaon multi-nucleon clusters. AMADEUS takes advantage of the DAΦ\PhiNE collider, which provides a unique source of monochromatic low-momentum kaons and exploits the KLOE detector as an active target, in order to obtain excellent acceptance and resolution data for KK^- nuclear capture on H, 4{}^4He, 9{}^{9}Be and 12{}^{12}C, both at-rest and in-flight. During the second half of 2012 a successful data taking was performed with a dedicated pure carbon target implemented in the central region of KLOE, providing a high statistic sample of pure at-rest KK^- nuclear interactions. For the future dedicated setups involving cryogenic gaseous targets are under preparation.Comment: 14 pages, 6 figure

    Perception de la parole et IRM : réalisation, évaluation et validation d'un système permettant une stimulation sonore de qualité en cours de séquence IRM

    No full text
    International audienceThis study describes the design and the assessment of a MRI-compatible sound production hardware. This system was developed to permit auditory studies with Magnetic Resonance Imaging (MRI) techniques. An important disadvantage caused by the MR imager is the acoustic noise generated during data acquisition, due to the fast gradient switching interacting with the main magnetic field. Several solutions were explored to reduce noise and to provide audio stimuli with a reasonable quality. The sound production system was first tested by instrumental methods (sound level, spectral analysis). Finally, perceptual tests consisting in intelligibility, semantic decision and prosodic judgement were achieved to validate the installation.Cette étude décrit la réalisation d'un dispositif de stimulation auditive pour un imageur à résonnance magnétique fonctionelle de 3 Tesla. Le plus important probléme de ces systémes réside dans l'émission d'un niveau de bruit considérable au cours de son fonctionnement qui les rend quasi impossible à utiliser pour des études en stimulation auditive.Plusieurs solutions de stimulation de réalisation locale sont proposées pour permettre de gérérer au tympan des sujet une stimulation de qualité raisonnable. Les stimulus ainsi générés sont d'abord testés au moyen de méthodes physiques classiques (analyses acoustiques). Ils sont ensuite testés au moyen de tests d'intelligibilité de décision sémantique et de jugement prosodique afin de les valider pour des études de psycho linguistique et psycho acoustique

    KK-series X-ray yield measurement of kaonic hydrogen atoms in a gaseous target

    Full text link
    We measured the KK-series X-rays of the KpK^{-}p exotic atom in the SIDDHARTA experiment with a gaseous hydrogen target of 1.3 g/l, which is about 15 times the ρSTP\rho_{\rm STP} of hydrogen gas. At this density, the absolute yields of kaonic X-rays, when a negatively charged kaon stopped inside the target, were determined to be 0.0120.003+0.004^{+0.004}_{-0.003} for KαK_{\alpha} and 0.0430.011+0.012^{+0.012}_{-0.011} for all the KK-series transitions KtotK_{tot}. These results, together with the KEK E228 experiment results, confirm for the first time a target density dependence of the yield predicted by the cascade models, and provide valuable information to refine the parameters used in the cascade models for the kaonic atoms.Comment: 9 pages, 5 figures. Submitted to Nuclear Physics A, Special Issue on Strangeness and Char
    corecore