4 research outputs found
Milky Way Demographics with the VVV Survey II. Color Transformations and Near-Infrared Photometry for 136 Million Stars in the Southern Galactic Disk
The new multi-epoch near-infrared VVV survey (VISTA Variables in the Via
Lactea) is sampling 562 sq. deg of the Galactic bulge and adjacent regions of
the disk. Accurate astrometry established for the region surveyed allows the
VVV data to be merged with overlapping surveys (e.g., GLIMPSE, WISE, 2MASS,
etc.), thereby enabling the construction of longer baseline spectral energy
distributions for astronomical targets. However, in order to maximize use of
the VVV data, a set of transformation equations are required to place the VVV
JHKs photometry onto the 2MASS system. The impetus for this work is to develop
those transformations via a comparison of 2MASS targets in 152 VVV fields
sampling the Galactic disk. The transformation coefficients derived exhibit a
reliance on variables such as extinction. The transformed data were
subsequently employed to establish a mean reddening law of
E_{J-H}/E_{H-Ks}=2.13 +/- 0.04, which is the most precise determination to date
and merely emphasizes the pertinence of the VVV data for determining such
important parameters.Comment: 24 pages, 12 figures, published in A&
PHYTOCHEMICAL SCREENING AND ANALYSIS POLYPHENOLIC ANTIOXIDANT ACTIVITY OF METHANOLIC EXTRACT OF WHITE DRAGON FRUIT (Hylocereus undatus)
White dragon fruit is a well known and widely used herbal
medicine, especially in Asia, which contains several interesting
bioactive constituents and possesses health promoting properties.
The aim of this study was to analyze for the bioactive
compounds, evaluate total phenolic contents and antioxidant
capacities of methanolic extract of white dragon fruit. The
antioxidant activity was determined by the 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging activity assay. Total
phenolic content were determined by Folin-Ciocalteu method.
Phytochemical screening of the white dragon fruit showed
the presence of triterpenoid, alkaloid, flavonoid and saponin.
The extract exhibited strong antioxidant activity with IC50 of
193 μg/mL, and total phenolic content of 246 μg/mL in 1 Kg dry
extract