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We present an algorithm for achieving background consistency in overlapping images. The algorithm consists of two main steps. First, the images are interpolated to a common grid. Second, the cumulative pixel-by-pixel difference between the overlapping areas of all pairs of images is minimized with respect to the unknown constant offsets of the input images. The images are corrected by adding the computed offsets. Optionally, detection and masking of bright objects in the images can be performed prior to minimization. This option is especially useful for images with a high density of cosmic-ray hits. We use simulated data to optimize the algorithm in order to achieve a trade-off between the speed of execution and the quality of the background matching. We also show several examples of the application of this algorithm to real Spitzer data. The algorithm has been implemented and successfully used by the Spitzer image processing package MOPEX (Makovoz & Khan) and deployed by the Spitzer automated pipeline.

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To explore new biocompatible antioxidants with the least associated side-effects, the present study was carried out to evaluate the antioxidant activity of leaf extracts of Abutilon indicum L. (Malvaceae). The methanol extract was prepared and screened for in vitro antioxidant activities using Ferric Reducing Antioxidant Power (FRAP) assay. The reducing power of a methanolic leaf extract of Abutilon indicum was markedly enhanced with the increasing concentrations. In addition, the potential antioxidant(s) from the plant extract of Abutilon indicum were partially purified by thin layer chromatography. The results indicate a strong antioxidant activity of the extract.

The Spitzer Space Telescope Infrared Array Camera (IRAC) basic calibrated data reduction pipeline is designed to take a single raw frame from a single IRAC detector and produce a flux-calibrated image that has had all well-understood instrumental signatures removed. We discuss several modifications to the pipeline developed in the last two years in response to the Spitzer warm mission. Due to the different instrument characteristics in the warm mission, we have significantly changed pipeline procedures for masking residual images and mitigating column pulldown. In addition, the muxbleed correction was turned off, because it is not present in the warm data. Parameters relevant to linearity correction, bad pixels, and the photometric calibration have been updated and are continually monitored.