255 research outputs found

    A comparison of retention following oral presentation or silent reading in grade three

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    Thesis (Ed. M.)--Boston University, 195

    Trace Level Arsenic Quantification through Methyl Red Bromination

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    A simple protocol has been developed for the quantification of trace level arsenic through methyl red bromination. The proposed method is based on the oxidation of arsenic(III) to arsenic(V) by the bromine and the residual bromine’s reaction with methyl red to form colorless bromo methyl red. As the concentration of arsenic increases, the bleaching of the dye decreases due to bromine consumption. Measuring the intensity of the unreacted methyl red at 515 nm forms the basis of arsenic quantification. The molar absorptivity of this method has been found to be 2.25 × 103 L/mol/cm. The method obeys Beer’s law in the concentration range 0 - 0.25 µg/mL. The Sandell sensitivity and the limit of detection (LOD) were found to be 0.03 µg/mL/cm2 and 0.03 µg/mL respectively. The relative standard deviation has been found to be 0.35% at 1.0 µg/mL. The reaction conditions have been optimized and the interference due to various common cations and anions were studied. The proposed method has been successfully applied to the determination of trace level arsenic in various environmental samples like water, soil and vegetable samples

    Relapse risk factors in anti-N-methyl-D-aspartate receptor encephalitis

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    Aim: To identify factors that may predict and affect the risk of relapse in anti-N-methyl-D-aspartate receptor (NMDAR) encephalitis. Method: This was a retrospective study of an Italian cohort of patients with paediatric (≤18y) onset anti-NMDAR encephalitis. Results: Of the 62 children included (39 females; median age at onset 9y 10mo, range 1y 2mo–18y; onset between 2005 and 2018), 21 per cent relapsed (median two total events per relapsing patient, range 2–4). Time to first relapse was median 31.5 months (range 7–89mo). Severity at first relapse was lower than onset (median modified Rankin Scale [mRS] 3, range 2–4, vs median mRS 5, range 3–5; admission to intensive care unit: 0/10 vs 3/10). At the survival analysis, the risk of relapsing was significantly lower in patients who received three or more different immune therapies at first disease event (hazard ratio 0.208, 95% confidence interval 0.046–0.941; p=0.042). Neurological outcome at follow-up did not differ significantly between patients with relapsing and monophasic disease (mRS 0–1 in 39/49 vs 12/13; p=0.431), although follow-up duration was significantly longer in relapsing (median 84mo, range 14–137mo) than in monophasic patients (median 32mo, range 4–108mo; p=0.002). Interpretation: Relapses may occur in about one-fifth of children with anti-NMDAR encephalitis, are generally milder than at onset, and may span over a long period, although they do not seem to be associated with severity in the acute phase or with outcome at follow-up. Aggressive immune therapy at onset may reduce risk of relapse. What this paper adds: Relapses of anti-N-methyl-D-aspartate receptor encephalitis may span over a long period. Relapses were not associated with severity in the acute phase or outcome at follow-up. Aggressive immune therapy at onset appears to decrease risk of relapse

    U.S. Environmental Protection Agency

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    This document has been reviewed in accordance with U.S. Environmental Protection Agency policy. Mention of trade names or commercial products does not constitute endorsement or recommendation for use. Note: This document may undergo revisions in the future. The mos
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