Single-exposure two-dimensional superresolution in digital holography using a vertical cavity surface-emitting laser source array

We present a new implementation capable of producing two-dimensional (2D) superresolution (SR) imaging in a single exposure by aperture synthesis in digital lensless Fourier holography when using angular multiplexing provided by a vertical cavity surface-emitting laser source array. The system performs the recording in a single CCD snapshot of a multiplexed hologram coming from the incoherent addition of multiple subholograms, where each contains information about a different 2D spatial frequency band of the object's spectrum. Thus, a set of nonoverlapping bandpass images of the input object can be recovered by Fourier transformation (FT) of the multiplexed hologram. The SR is obtained by coherent addition of the information contained in each bandpass image while generating an enlarged synthetic aperture. Experimental results demonstrate improvement in resolution and image quality.     

The effect of the nature of the organic solvent on the gamma radiolysis of cholesteric esters

The relative efficiency of various chlorinated compounds as solvents for color transition temperatures lowering due to radiolysis is shown to be due to the C-Cl bond strength in the solvent.     

Structural analysis of complex saponins of Balanites aegyptiaca by 800 MHz 1H NMR spectroscopy

The main saponin (1) present in the mesocarp of Balanites aegyptiaca fruit is a mixture of 22R and 22S epimers of 26-(O-beta-D-glucopyranosyl)-3-beta-[4-O-(beta-D-glucopyranosyl)-2-O-(alpha-L-rhamnopyranosyl)-beta-D-glucopyranosyloxy]-22,26-dihydroxyfurost-5-ene. This structure differs from a previously reported saponin isolated from this source by the site of attachment of the rhamnosyl residue, and presumably represents a structural revision of the latter. The main saponin (2) present in the kernel is a xylopyranosyl derivative of 1. The use of high-field NMR enabled the practically complete assignment of 1H and 13C chemical shifts of these complex saponins, existing as a mixture of C-22 epimers. Moreover, the work represents a new approach to structural elucidation of saponins: direct preparative-scale HPLC-RID of crude extracts followed by high-field NMR investigations supported by ESI-MSn.     

The chemistry of polycyclic arene imines. I. Substitution at the nitrogen atom of 1a,9b-dihydro-1H-phenanthro[9,10-b]azirine

Chlorides of carboxylic, sulfonic and phosphoric acids proved to convert phenanthrene-9,10-imine into the corresponding rearranged acet- sulfon- and phosphonamidophenanthrene. Trimethylchlorosilane and N,O-bis(trimethylsilyl)acetamide reacted with the imine without destruction of the aziridine ring. The silylated compound could be transferred into the respective N-substituted phenanthrene-9,10-imines when treated with acetyl-, methanesulfonyl-, 4-tosyl- and diethylphosphoryl chloride. A remarkably stable N-chlorophenanthrene-9,10-imine was obtained from the unsubstituted compound and N-chlorosuccinimide.