152 research outputs found

    Calixarene bulk modified screen-printed electrodes (SPCCEs) as a one-shot disposable sensor for the simultaneous detection of lead(II), copper(II) and mercury(II) ions: Application to environmental samples

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    Calixarene bulk modified screen-printed electrodes (SPCCEs) have been designed, fabricated and utilized as one-shot disposable electrochemical sensors towards the simultaneous measurement of toxic metal ions lead(II), copper(II) and mercury(II) within environmental samples. These SPCCEs have been fabricated upon polyester strips, which have been modified over a range of different calixarene compositions. These bespoke sensors have been utilized as disposable electrochemical sensors and quantified in model aqueous solution of 0.1 M HCl giving rise to the simultaneous sensing of lead(II), copper(II) and mercury(II) using cyclic voltammetry and differential pulse anodic stripping voltammetry techniques. These SPCCEs have additionally been applied for the sensing of lead(II), copper(II) and mercury(II) within industrial and environmental samples such as industrial effluents and wastewater samples, furthermore the presented method has been subjected to a comprehensive interference study and further validated with an atomic absorption spectrometric method. © 2017 Elsevier B.V

    Is it possible to recover information from the black-hole radiation?

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    In the framework of communication theory, we analyse the gedanken experiment in which beams of quanta bearing information are flashed towards a black hole. We show that stimulated emission at the horizon provides a correlation between incoming and outgoing radiations consisting of bosons. For fermions, the mechanism responsible for the correlation is the Fermi exclusion principle. Each one of these mechanisms is responsible for the a partial transfer of the information originally coded in the incoming beam to the black--hole radiation. We show that this process is very efficient whenever stimulated emission overpowers spontaneous emission (bosons). Thus, black holes are not `ultimate waste baskets of information'.Comment: 9 pages (2 figures available upon request), CERN-TH 6811/93, (LateX file

    One-pot synthesis of Mn3O4/graphitic carbon nanoparticles for simultaneous nanomolar detection of Pb(II), Cd(II) and Hg(II)

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    In this paper, a facile one-step sucrose–nitrate decomposition method has been proposed to synthesis Mn3O4 nanoparticles (Mns)/graphitic carbon. The prepared material has been characterized by X-ray diffraction, Fourier transform infrared spectrometer, surface area analysis and transmission electron microscopy. The prepared Mns/graphitic carbon is drop-casted on glassy carbon electrode to allow the fabrication of electrochemical sensors for the simultaneous detection of Pb(II), Cd(II) and Hg(II) at nanomolar (nM) levels in aqueous solutions via differential pulse anodic stripping voltammetry. The proposed Mns/graphitic carbon sensors exhibit a wide linear range from 20 to 680 nM towards the simultaneous sensing of Cd(II), Pb(II) and Hg(II), and the corresponding limits of detection were found to be 0.48 × 10−11, 9.66 × 10−11 and 0.51 × 10−11 M, respectively. The practical application of the proposed sensor is evaluated within a real battery, industrial and chrome plating effluents

    Noncommutativity, generalized uncertainty principle and FRW cosmology

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    We consider the effects of noncommutativity and the generalized uncertainty principle on the FRW cosmology with a scalar field. We show that, the cosmological constant problem and removability of initial curvature singularity find natural solutions in this scenarios.Comment: 8 pages, to appear in IJT

    Possible Effects of Noncommutative Geometry on Weak CP Violation and Unitarity Triangles

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    Possible effects of noncommutative geometry on weak CP violation and unitarity triangles are discussed by taking account of a simple version of the momentum-dependent quark mixing matrix in the noncommutative standard model. In particular, we calculate nine rephasing invariants of CP violation and illustrate the noncommutative CP-violating effect in a couple of charged D-meson decays. We also show how inner angles of the deformed unitarity triangles are related to CP-violating asymmetries in some typical B_d and B_s transitions into CP eigenstates. B-meson factories are expected to help probe or constrain noncommutative geometry at low energies in the near future.Comment: RexTev 16 pages. Modifications made. References added. Accepted for publication in Phys. Rev.

    Astrophysical and cosmological considerations on a string dilaton of a least coupling

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    String-loop effects may generate very weak matter couplings for a (massless) dilaton. We examine limits on the shift of such a dilaton toward its present equilibrium value from big-bang nucleosynthesis and the binary pulsar. On the other hand, the approach of the dilaton toward its present value can be realized in the early universe in a quick and efficient way if an inflationary period is present. We comment briefly on some implications.Comment: Revised version to appear in Astropart.Phys., numerical correction of the binary pulsar constraint. 18 pages, late

    Designing a mHealth clinical decision support system for Parkinson's disease: a theoretically grounded user needs approach.

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    BACKGROUND: Despite the established evidence and theoretical advances explaining human judgments under uncertainty, developments of mobile health (mHealth) Clinical Decision Support Systems (CDSS) have not explicitly applied the psychology of decision making to the study of user needs. We report on a user needs approach to develop a prototype of a mHealth CDSS for Parkinson's disease (PD), which is theoretically grounded in the psychological literature about expert decision making and judgement under uncertainty. METHODS: A suite of user needs studies was conducted in 4 European countries (Greece, Italy, Slovenia, the UK) prior to the development of PD_Manager, a mHealth-based CDSS designed for Parkinson's disease, using wireless technology. Study 1 undertook Hierarchical Task Analysis (HTA) including elicitation of user needs, cognitive demands and perceived risks/benefits (ethical considerations) associated with the proposed CDSS, through structured interviews of prescribing clinicians (N = 47). Study 2 carried out computational modelling of prescribing clinicians' (N = 12) decision strategies based on social judgment theory. Study 3 was a vignette study of prescribing clinicians' (N = 18) willingness to change treatment based on either self-reported symptoms data, devices-generated symptoms data or combinations of both. RESULTS: Study 1 indicated that system development should move away from the traditional silos of 'motor' and 'non-motor' symptom evaluations and suggest that presenting data on symptoms according to goal-based domains would be the most beneficial approach, the most important being patients' overall Quality of Life (QoL). The computational modelling in Study 2 extrapolated different factor combinations when making judgements about different questions. Study 3 indicated that the clinicians were equally likely to change the care plan based on information about the change in the patient's condition from the patient's self-report and the wearable devices. CONCLUSIONS: Based on our approach, we could formulate the following principles of mHealth design: 1) enabling shared decision making between the clinician, patient and the carer; 2) flexibility that accounts for diagnostic and treatment variation among clinicians; 3) monitoring of information integration from multiple sources. Our approach highlighted the central importance of the patient-clinician relationship in clinical decision making and the relevance of theoretical as opposed to algorithm (technology)-based modelling of human judgment

    Electroproduction and Hadroproduction of Light Gluinos

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    In a class of supergravity models, the gluino and photino are massless at tree level and receive small masses through radiative corrections. In such models, one expects a gluino-gluon bound state, the R0R_0, to have a mass of between 1.0 and 2.2 GeV and a lifetime between 10−1010^{-10} and 10−610^{-6} seconds. Applying peturbative QCD methods (whose validity we discuss), we calculate the production cross sections of R0R_0's in e−pe-p, π−p\pi-p, K−pK-p, p‟−p\overline{p}-p and p−pp-p collisions. Signatures are also discussed.Comment: 10 pages, latex, 6 figures uuencoded, figures also available via anonymous ftp to ftp://physics.wm.edu/pub/gluinofig.p

    Large-scale pathways-based association study in amyotrophic lateral sclerosis

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    Sporadic amyotrophic lateral sclerosis (ALS), a devastating neurodegenerative disease, most likely results from complex genetic and environmental interactions. Although a number of association studies have been performed in an effort to find genetic components of sporadic ALS, most of them resulted in inconsistent findings due to a small number of genes investigated in relatively small sample sizes, while the replication of results was rarely attempted. Defects in retrograde axonal transport, vesicle trafficking and xenobiotic metabolism have been implicated in neurodegeneration and motor neuron death both in human disease and animal models. To assess the role of common genetic variation in these pathways in susceptibility to sporadic ALS, we performed a pathway-based candidate gene case-control association study with replication. Furthermore, we determined reliability of whole genome amplified DNA in a large-scale association study. In the first stage of the study, 1277 putative functional and tagging SNPs in 134 genes spanning 8.7 Mb were genotyped in 822 British sporadic ALS patients and 872 controls using whole genome amplified DNA. To detect variants with modest effect size and discriminate among false positive findings 19 SNPs showing a trend of association in the initial screen were genotyped in a replication sample of 580 German sporadic ALS patients and 361 controls. We did not detect strong evidence of association with any of the genes investigated in the discovery sample (lowest uncorrected P-value 0.00037, lowest permutation corrected P-value 0.353). None of the suggestive associations was replicated in a second sample, further excluding variants with moderate effect size. We conclude that common variation in the investigated pathways is unlikely to have a major effect on susceptibility to sporadic ALS. The genotyping efficiency was only slightly decreased (∌1%) and genotyping quality was not affected using whole genome amplified DNA. It is reliable for large scale genotyping studies of diseases such as ALS, where DNA sample collections are limited because of low disease prevalence and short survival time. © 2007 The Author(s)
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