3,056 research outputs found

    Different chemical behaviors and antioxidant activity of three novel schiff bases containing hydroxyl groups. X-ray structure of CH2{cyclo-C6H10-NH=CH-(2-O-naphth)}2.H2O

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    The antioxidant activities of three new Schiff base compounds, 1–3, were studied through their direct scavenging ability to eliminate free radicals using DPPH and ABTS methods and also through their indirect antioxidant activity as measured using the ferric thiocyanate (FTC) method. The number of OH groups in the compounds and their positions play a role in the activity. The crystal structure of CH2{cycloC6H10NHCH-(2-O-naphth)}2.H2O (1), has been determined and proves the existence of intramolecular hydrogen-bonds and hydrogen-bonded water molecules and reveals the keto-amine (NH⋯O) tautomer of this compound. One cyclo-hexyl ring was found to be disordered, and was resolved in two orientations. Hydrogen atoms of the NHCH groups were located in difference maps and were refined freely. Compounds 2 and 3 exhibit the enol-imine form. The UV–vis spectra of the three compounds have been studied in organic solvents of different polarity, and in basic and acidic media, and were found helpful in understanding the tautomeric forms in these compounds; the polarity was modified by adding (CF3COOH) or [(C2H5)3N] to the solvent. All three compounds have been characterized by elemental analysis, UV–vis, FTIR, NMR and MS

    Crystal structure of 5-(adamantan-1-yl)-3-= (4-chloroanilino)methyl-2,3-dihydro-1,3,4-oxadiazole-2-thione, C19H22ClN3OS

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    Abstract C19H22ClN3OS, orthorhombic, P212121 (no. 19), a = 7.0418(2) Å, b = 10.8802(3) Å, c = 23.5506(6) Å, V = 1804.36(8) Å3, Z = 4, R gt (F) = 0.0413, wR ref (F 2 ) = 0.1110, T = 100 K.</jats:p

    Sensory Electrical Stimulation Improves Foot Placement during Targeted Stepping Post-Stroke

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    Proper foot placement is vital for maintaining balance during walking, requiring the integration of multiple sensory signals with motor commands. Disruption of brain structures post-stroke likely alters the processing of sensory information by motor centers, interfering with precision control of foot placement and walking function for stroke survivors. In this study, we examined whether somatosensory stimulation, which improves functional movements of the paretic hand, could be used to improve foot placement of the paretic limb. Foot placement was evaluated before, during, and after application of somatosensory electrical stimulation to the paretic foot during a targeted stepping task. Starting from standing, twelve chronic stroke participants initiated movement with the non-paretic limb and stepped to one of five target locations projected onto the floor with distances normalized to the paretic stride length. Targeting error and lower extremity kinematics were used to assess changes in foot placement and limb control due to somatosensory stimulation. Significant reductions in placement error in the medial–lateral direction (p = 0.008) were observed during the stimulation and post-stimulation blocks. Seven participants, presenting with a hip circumduction walking pattern, had reductions (p = 0.008) in the magnitude and duration of hip abduction during swing with somatosensory stimulation. Reductions in circumduction correlated with both functional and clinical measures, with larger improvements observed in participants with greater impairment. The results of this study suggest that somatosensory stimulation of the paretic foot applied during movement can improve the precision control of foot placement

    An empirical investigation of the factors contributing to spreadsheets usage and end-user computing satisfaction

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    The purpose of this research is to develop and test a model of the relationships between several external and various mediating variables and the end-users' satisfaction and usage of spreadsheets. The present research takes several steps toward establishing a valid motivational model of the end-users. Two fairly general, well-established theoretical models (i) 'theory of reasoned action' (TRA) of human behaviour from social psychology and (ii) 'technology acceptance model' (TAM) from management information systems were chosen as paradigms within which to formulate an extended model Several adaptations to these paradigms were introduced in order to make them applicable to the present context building upon and integrating previous research in a curnulative manner. This led to a model which was tested by a nine page questionnaire with 129 entries. Response data was collected from a cross-sectional survey of 333 university students who have been out for one year training in industry across the UK. A careful reliability and validity analysis for the measures used in the survey was conducted. Multiple regression analysis, path analysis, and LISREL modelling were used as different data analysis techniques. The analysis in part gave good support for the initial model considered but also indicated some shortcomings in the two base models

    Search for the decay B+K0K+B^+\rightarrow\overline{K}{}^{*0}K^{*+} at Belle

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    We report a search for the rare charmless decay B+K0K+B^+\rightarrow\overline{K}{}^{*0}K^{*+} using a data sample of 772×106772\times10^6 BBˉB\bar{B} pairs collected at the Υ(4S)\Upsilon(4S) resonance with the Belle detector at the KEKB asymmetric-energy e+ee^+e^- collider. No statistically significant signal is found and a 90% confidence-level upper limit is set on the decay branching fraction as B(B+K0K+)<1.31×106 \mathcal{B}(B^+\rightarrow\overline{K}{}^{*0}K^{*+}) <1.31\times 10^{-6}.Comment: 8 pages, 3 figures, submitted to PRD(RC

    Measurements of the Υ(10860)\Upsilon(10860) and Υ(11020)\Upsilon(11020) resonances via σ(e+eΥ(nS)π+π)\sigma(e^+e^-\rightarrow\Upsilon(n{\rm S})\pi^+\pi^-)

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    We report new measurements of the total cross sections for e+eΥ(nS)π+πe^+e^-\to \Upsilon(n{\rm S})\pi^+\pi^- (nn = 1, 2, 3) and e+ebbˉe^+e^-\to b\bar b from a high-luminosity fine scan of the region s=10.63\sqrt{s} = 10.63-11.0511.05 GeV with the Belle detector. We observe that the Υ(nS)π+π\Upsilon(n{\rm S})\pi^+\pi^- spectra have little or no non-resonant component and extract from them the masses and widths of Υ(10860)\Upsilon(10860) and Υ(11020)\Upsilon(11020) and their relative phase. We find M10860=(10891.1±3.21.7+0.6)M_{10860}=(10891.1\pm3.2^{+0.6}_{-1.7}) MeV/c2c^2 and Γ10860=(53.75.6+7.15.4+1.3)\Gamma_{10860}=(53.7^{+7.1}_{-5.6}\,^{+1.3}_{-5.4}) MeV and report first measurements M11020=(10987.52.5+6.42.1+9.0)M_{11020}=(10987.5^{+6.4}_{-2.5}\,^{+9.0}_{-2.1}) MeV/c2c^2, Γ11020=(6119+920+2)\Gamma_{11020}=(61^{+9}_{-19}\,^{+2}_{-20}) MeV, and ϕ11020ϕ10860=(1.0±0.40.1+1.4)\phi_{\rm 11020}-\phi_{\rm 10860} = (-1.0\pm0.4\,^{+1.4}_{-0.1}) rad.Comment: University of Cincinnati preprint UCHEP-15-01, submitted to Physical Review D - Rapid Communication

    Measurement of the CKM Matrix Element Vcb|V_{cb}| from B0D+νB^{0} \to D^{*-} \ell^+ \nu_\ell at Belle

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    We present a new measurement of the CKM matrix element Vcb|V_{cb}| from B0D+νB^{0} \to D^{*-} \ell^+ \nu_\ell decays, reconstructed with the full Belle data set of 711fb1711 \, \rm fb^{-1} integrated luminosity. Two form factor parameterizations, originally conceived by the Caprini-Lellouch-Neubert (CLN) and the Boyd, Grinstein and Lebed (BGL) groups, are used to extract the product F(1)ηEWVcb\mathcal{F}(1)\eta_{\rm EW}|V_{cb}| and the decay form factors, where F(1)\mathcal{F}(1) is the normalization factor and ηEW\eta_{\rm EW} is a small electroweak correction. In the CLN parameterization we find F(1)ηEWVcb=(35.06±0.15±0.56)×103\mathcal{F}(1)\eta_{\rm EW}|V_{cb}| = (35.06 \pm 0.15 \pm 0.56) \times 10^{-3}, ρ2=1.106±0.031±0.007\rho^{2}=1.106 \pm 0.031 \pm 0.007, R1(1)=1.229±0.028±0.009R_{1}(1)=1.229 \pm 0.028 \pm 0.009, R2(1)=0.852±0.021±0.006R_{2}(1)=0.852 \pm 0.021 \pm 0.006. For the BGL parameterization we obtain F(1)ηEWVcb=(34.93±0.23±0.59)×103\mathcal{F}(1)\eta_{\rm EW}|V_{cb}|= (34.93 \pm 0.23 \pm 0.59)\times 10^{-3}, which is consistent with the World Average when correcting for F(1)ηEW\mathcal{F}(1)\eta_{\rm EW}. The branching fraction of B0D+νB^{0} \to D^{*-} \ell^+ \nu_\ell is measured to be B(B0D+ν)=(4.90±0.02±0.16)%\mathcal{B}(B^{0}\rightarrow D^{*-}\ell^{+}\nu_{\ell}) = (4.90 \pm 0.02 \pm 0.16)\%. We also present a new test of lepton flavor universality violation in semileptonic BB decays, B(B0De+ν)B(B0Dμ+ν)=1.01±0.01±0.03 \frac{{\cal B }(B^0 \to D^{*-} e^+ \nu)}{{\cal B }(B^0 \to D^{*-} \mu^+ \nu)} = 1.01 \pm 0.01 \pm 0.03~. The errors correspond to the statistical and systematic uncertainties respectively. This is the most precise measurement of F(1)ηEWVcb\mathcal{F}(1)\eta_{\rm EW}|V_{cb}| and form factors to date and the first experimental study of the BGL form factor parameterization in an experimental measurement

    Measles on the Rise: The importance of vaccination

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