2,955 research outputs found

    Mean Occupation Function of High Redshift Quasars from the Planck Cluster Catalog

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    We characterise the distribution of quasars within dark matter halos using a direct measurement technique for the first time at redshifts as high as z1z \sim 1. Using the Planck Sunyaev-Zeldovich (SZ) catalogue for galaxy groups and the Sloan Digital Sky Survey (SDSS) DR12 quasar dataset, we assign host clusters/groups to the quasars and make a measurement of the mean number of quasars within dark matter halos as a function of halo mass. We find that a simple power-law fit of \log\left = (2.11 \pm 0.01) \log (M) -(32.77 \pm 0.11) can be used to model the quasar fraction in dark matter halos. This suggests that the quasar fraction increases monotonically as a function of halo mass even to redshifts as high as z1z\sim 1.Comment: Accepted for publication in PAS

    ANTIOXIDANT POTENTIAL PROFILE OF PAJANELIA LONGIFOLIA (WILLD.) K. SCHUMAN.; POTENTIAL NEW SOURCES OF NATURAL ANTIOXIDANT.

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    Objectives: The aim of the present work is to screen the antioxidant potentiality of the bark extracts of Pajanelia longifolia (Willd.) K. Schuman, ethnomedicinally prescribed plant as hepatoprotective. Methods: Bark extract was prepared using Soxhlet apparatus. Total phenol, flavonoid, total alkaloid were analyzed using Folin–Ciocalteu assay, aluminum chloride calorimetric assay, atropine standard, respectively. Antioxidant capacity and free radical scavenging potentialities were done by various in vitro methods, viz.; 1,1-diphenyl-2-picrylhydrazyl (DPPH), hydrogen peroxide scavenging activity, reducing power assay, metal chelating activity, ferric reducing antioxidant power (FRAP) assay, and thiobarbituric acid (TBA) method. Result: Total phenol, flavonoid, and alkaloid were found to be highest in acetone extract of P. longifolia (Willd.) K. Schuman. Acetone extracts of the bark of P. longifolia (Willd.) K. Schuman showed very low inhibitory concentration 50 (IC50) and effective concentration 50 values for DPPH assay and reducing power assay compared to other extracts. In hydrogen peroxide scavenging activity assay, the lowest IC50 value was recorded in acetone extract with 181.78±0.09 μg/ml in P. longifolia. The FRAP assay for P. longifolia acetone extract showed the highest activity at 967±0.69 μg/ml of ascorbic acid equivalent. The ferric reducing capacity and TBA values of the plant extracts confirmed the presence antioxidant principles in the bark of the said plant. Conclusion: These underused plants may be used for mitigating the detrimental effect of oxidative stress and reactive oxygen species-mediated disease and thus justifies its use in folklore medicines.Â

    Integrated graphene quantum dot decorated functionalized nanosheet biosensor for mycotoxin detection

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    Decoration of graphene quantum dots (GQDs) on molybdenum disulfide (MoS2) nanosheets serves as an active electrode material which enhances the electrochemical performance of the analyte detection system. Herein, ionic surfactant cetyltrimethylammonium bromide (CTAB)-exfoliated MoS2 nanosheets decorated with GQD material are used to construct an electrochemical biosensor for aflatoxin B1 (AFB1) detection. An antibody of AFB1 (aAFB1) was immobilized on the electrophoretically deposited MoS2@GQDs film on the indium tin oxide (ITO)-coated glass surface using a crosslinker for the fabrication of the biosensor. The immunosensing study investigated by the electrochemical method revealed a signal response in the range of 0.1 to 3.0 ng/mL AFB1 concentration with a detection limit of 0.09 ng/mL. Also, electrochemical parameters such as diffusion coefficient and heterogeneous electron transfer (HET) were calculated and found to be 1.67 x 10(-5) cm(2)/s and 2 x 10(-5)cm/s, respectively. The effective conjugation of MoS2@GQDs that provides abundant exposed edge sites, large surface area, improved electrical conductivity, and electrocatalytic activity has led to an excellent biosensing performance with enhanced electrochemical parameters. Validation of the fabricated immunosensor was performed in a spiked maize sample, and a good percentage of recoveries within an acceptable range were obtained (80.2 to 98.3%)

    STATISTICAL ANALYSIS FOR PERFORMANCE COMPARISON

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    ABSTRAC

    IN VITRO ANTIOXIDANT ACTIVITY OF BARK EXTRACTS OF OROXYLUM INDICUM (L) VENT

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      Objectives: The aim of the present work is to screen the antioxidant potentiality of the bark extract of Oroxylum indicum (L) Vent, ethnomedicinally prescribed plant as hepatoprotective.Methods: Bark extracts were prepared using soxhlet apparatus. Total phenol, flavonoid, and total alkaloid were analyzed using Folin–Ciocalteu assay, aluminum chloride colorimetric assay, atropine standard, respectively. Antioxidant capacity and free radical scavenging potentialities were done by several in vitro methods, viz.; 1,1-diphenyl-2-picrylhydrazyl (DPPH), hydrogen peroxide scavenging activity, reducing power assay, metal chelating activity, ferric reducing ability of plasma (FRAP) assay, and thiobarbituric acid (TBA) method.Result: Total phenol, flavonoid, and alkaloid were found to be highest in methanolic extract of O. indicum (L) Vent. Methanolic extract of the bark showed very low inhibitory concentration (IC50) and effective concentration values for DPPH assay and reducing power assay compared to another extract. In hydrogen peroxide scavenging activity assay, the lowest IC50 value was recorded in methanolic extract with 153.45±0.06 μg/ml. The FRAP assay for O. indicum methanolic extract showed the highest activity at 940.09±0.07 μg/mL of ascorbic acid equivalent. The ferric reducing capacity and TBA values of the plant extracts confirmed the presence antioxidant principles in the bark of the said plant.Conclusion: These underused plants may be used for mitigating the detrimental effect of oxidative stress and reactive oxygen species-mediated disease and thus justifies its use in folklore medicines
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