PHOTOCATALYTICDEGRADATION OF RHODAMIN-B USING METAL COMPLEXES AND HYDROGEN PEROXIDE

ABSTRACT The photocatalytic degradation has been considered to be an efficient process for degradation of organic pollutants, which are present in the effluents released by industries. Thephotocatalytic bleaching was carried out on rhodamin-B (cationic dye) in the presence of iron (III) complex, hydrogen peroxide and was observed spectrophotometrically. The effect of various operating variables like pH, concentration of complex and dye, amount of HzOzand light intensity etc. was also observed on the efficiency of the reaction. A tentative mechanism has also been proposed for this photocatalytic degradation of rhodamin-B. Keywords: Photocatalytic degradation, rhodamin-B, metal complexes, hydrogen peroxide

AN OVERVIEW OF OBSERVATIONAL SLEEP RESEARCH WITH APPLICATION TO SLEEP STAGE TRANSITIONING

In this manuscript we give an overview of observational sleep research with a particular emphasis on sleep stage transitions. Sleep states represent a categorization of sleep electroencephalogram behavior over the night. We postulate that the rate of transitioning between sleep states is an important predictor of health. This claim is evaluated by comparing subjects with sleep disordered breathing to matched controls

Nucleon electroweak form factors in a meson-cloud model

The meson-cloud model of the nucleon consisting of a system of three valence quarks surrounded by a meson cloud is applied to study the electroweak structure of the proton and neutron. The electroweak nucleon form factors are calculated within a light-front approach, by obtaining an overall good description of the experimental data. Charge densities as a function of the transverse distance with respect to the direction of the three-momentum transfer are also discussed.Comment: Prepared for Proceedings of NSTAR2007, Workshop on the physics of excited nucleons, Bonn (Germany), 5-8 September 200

Relativistic Description of Exclusive Deuteron Breakup Reactions

The exclusive deuteron break-up reaction is analyzed within a covariant approach based on the Bethe-Salpeter equation with realistic meson-exchange interaction. Relativistic effects in the cross section, tensor analyzing power and polarization transfer are investigated in explicit form. Results of numerical calculations are presented for kinematical conditions in forthcoming p + D reactions at COSY.Comment: 10 LaTeX pages, 4 eps-figure

Dye-sensitized Photo-oxygenation of Nitrofurazone by Singlet Oxygen

Dye-sensitized photo-oxygenation of nitrofurazone by singlet oxygen has been carried out under various reaction conditions, including changes in solvents and sensitizers. The product has been isolated and characterized by elemental analysis, physical, chemical and spectral data. A suitable mechanism has been proposed for the formation of photoproduct. To confirm the participation of singlet oxygen in the reaction, singlet oxygen scavengers have been used in the photo-oxygenation reaction

Enhanced photocatalytic degradation of nigrosine dye from its aqueous solution using La2Ce2O7 nanoparticles

172-179In the present work, removal of nigrosine dye from its aqueous solution via combined photocatalysis and adsorption has been reported using ternary catalyst lanthanum cerate under visible light. The catalyst has been synthesized by citric acid assisted sol-gel method. XRD graph reveals that the average crystallite size of sample is found to be approximate 4.0 nm having cubic fluorite structure. There is 64.45% oxygen. 17.76% lanthanum and 17.79% cerium atoms present in the material, as observed by EDS result. FESEM results shows that obtained particles are in the form of rice grain shape arranged densely in homogeneous manner. TGA curve shows that there is a evaporation of moisture, nitrate and carbon. Two exothermic peaks are observed at about 170°C and 200°C in the DTA curve. The UV-Visible spectrum gives the band gap of lanthanum cerate and it is 3.0 eV. A spectrophotometer has been used to follow the photocatalytic degradation of nigrosine dye at specific intervals of time. The effect of various parameters such as pH, concentration of dye, photocatalyst dosage and light intensity has been studied on the rate of degradation. A tentative mechanism for degradation of nigrosine has been proposed involving superoxide and hydroperoxyl radicals as main oxidizing species

Abnormalities in autonomic function in obese boys at-risk for insulin resistance and obstructive sleep apnea.

Study objectivesCurrent evidence in adults suggests that, independent of obesity, obstructive sleep apnea (OSA) can lead to autonomic dysfunction and impaired glucose metabolism, but these relationships are less clear in children. The purpose of this study was to investigate the associations among OSA, glucose metabolism, and daytime autonomic function in obese pediatric subjects.MethodsTwenty-three obese boys participated in: overnight polysomnography; a frequently sampled intravenous glucose tolerance test; and recordings of spontaneous cardiorespiratory data in both the supine (baseline) and standing (sympathetic stimulus) postures.ResultsBaseline systolic blood pressure and reactivity of low-frequency heart rate variability to postural stress correlated with insulin resistance, increased fasting glucose, and reduced beta-cell function, but not OSA severity. Baroreflex sensitivity reactivity was reduced with sleep fragmentation, but only for subjects with low insulin sensitivity and/or low first-phase insulin response to glucose.ConclusionsThese findings suggest that vascular sympathetic activity impairment is more strongly affected by metabolic dysfunction than by OSA severity, while blunted vagal autonomic function associated with sleep fragmentation in OSA is enhanced when metabolic dysfunction is also present

A Comparison of Polarization Observables in Electron Scattering from the Proton and Deuteron

Recoil proton polarization observables were measured for both the p($\vec {\rm e}$,e$^\prime\vec{\rm p}\,$) and d($\vec {\rm e}$,e$^\prime\vec{\rm p}\,)$n reactions at two values of Q$^2$ using a newly commissioned proton Focal Plane Polarimeter at the M.I.T.-Bates Linear Accelerator Center. The hydrogen and deuterium spin-dependent observables $D_{\ell\ell}$ and $D_{{\ell}t}$, the induced polarization $P_n$ and the form factor ratio $G^p_E/G^p_M$ were measured under identical kinematics. The deuterium and hydrogen results are in good agreement with each other and with the plane-wave impulse approximation (PWIA).Comment: 9 pages, 1 figure; accepted by Phys. Rev. Let