Differential and Temporal Immunomodulation of alpha4 Integrins on CD4+ Memory Cells by Bordetella pertussis and Bordetella parapertussis

Pertussis, caused by Bordetella pertussis (B. pertussis), is reemerging worldwide due to vaccine inefficacy. The hallmarks of infection are extreme lymphocytosis and delayed recovery, which are partially associated with pertussis toxin. Lymphocytes migrate to infected tissues using trafficking receptors. Specific combinations of these lymphocyte trafficking receptors are identified for skin and gut but are not well established for lung. This study focused on the effect of pertussis toxin on lung-associated trafficking receptors and tested the hypothesis that pertussis toxin alters dendritic cell imprinting of lung trafficking receptors on T cells, thus delaying resolution of the infection. B. pertussis-infected mice were compared with pertussis toxin-deficient strains. Imprinting of trafficking receptors on allogeneic T cells by dendritic cells derived from Bordetella-infected mice was analyzed by flow cytometry. Mice infected with Bordetella strains showed an increase in mature dendritic cells on day 5 post-infection. Despite their mature phenotype, dendritic cells from B. pertussis infection, were compromised in their ability to imprint lung trafficking receptors on allogenic T cells. These results indicated a pertussis toxin-dependent defect in dendritic cell imprinting of lung trafficking receptors on T cells. In conclusion, this study provides important data for future vaccine development against respiratory pathogens

Optical Absorption in B13_{13} Cluster: A Time-Dependent Density Functional Approach

The linear optical absorption spectra of three isomers of planar boron cluster B$_{13}$ are calculated using time-dependent spin-polarized density functional approach. The geometries of these cluster are optimized at the B3LYP/6-311+G* level of theory. Even though the isomers are almost degenerate, the calculated spectra are quite different, indicating a strong structure-property relationship. Therefore, these computed spectra can be used in the photo-absorption experiments to distinguish between different isomers of a cluster.Comment: Version2: Latex and hyperref enabled. Minor typos corrected. 4 figures, 2 pages. Accepted manuscript. To appear in AIP Conference Proceeding

Twin Telescope observations of the Sun at Kodaikanal Observatory

We report the design, fabrication and installation of a 'Twin Telescope' at Kodaikanal Observatory intended to augment the ongoing synoptic observations of the Sun that has been carried out since 1904. The telescope uses a 15 cm objective capable of taking Ca-K line filtergrams and photoheliograms in continuum of the full disk of the Sun simultaneously, at a frequency of 0.1 Hz using 2kx2k format CCD cameras. The telescope has been in operation since February 2008 and images are being obtained at a cadence of 5 min during normal observing periods. In case of solar activity, images of the active regions can be taken at a frequency of 1 Hz by restricting the field of view and spatial resolution. In this paper, we describe the telescope, instruments, image acquisition, data calibration and image processing. We also discussed a method of determining the network element and plage area index. The preliminary results show that while the network element covers about 30% of the disk, the percentage of the network element area index varies marginally with the seeing conditions during the day.Comment: 17 pages, 10 Figures, to appear in the 2012 March issue of the Bulletin of the Astronomical Society of Indi