ABSTRACT
A miniaturized sensor head for the optical measurement of velocities of fluids based on laser Doppler velocimetry is demonstrated. Holographic optical elements mounted on a glass substrate are used for beam splitting and deflection. Volume holograms in dichromated gelatin exhibit good optical efficiency (75% transmission of a cascade of two holographic optical elements). With diffractive devices one can achieve achromatic behavior that makes the sensor insensitive to wavelength drifts or mode hopping of a semiconductor laser.
ABSTRACT
Space-variant optical elements are necessary for realizing optical interconnects of arbitrary design. For such applications, planar holographic optical elements offer the highest degree of flexibility and ease of production; however their diffraction-based operation gives rise to chromatic aberrations. Here estimates for the number of independent space-variant interconnects, their spatial tolerances, and their wavelength stability are considered for close-cascade, and related, geometries.
Subject(s)
Granuloma/immunology , Periapical Granuloma/immunology , Animals , Dental Caries , Dentin , Foreign-Body Reaction/etiology , Foreign-Body Reaction/immunology , Foreign-Body Reaction/pathology , Glass , Granuloma/etiology , Granuloma/pathology , Histocytochemistry , Humans , Immunity, Cellular , Monophenol Monooxygenase/metabolism , RatsABSTRACT
With the aid of the histochemical phenoloxidase (PO) assay, 12 substances were tested. On the one side they can act as substrates or as inhibitors of phenoloxidase and on the other side as immunogenic or immunosuppressive compounds. In particular the following substances were investigated: o-cresol, Levamisol, prednisolonebisuccinate, Bleocin, siliciumdioxide, 4-methylbrenzcatechol, +-catechine, thiomersal, D-penicillamine, hydrochinonemonomethylether, hydrochinonemonoethylether, and hydrochinonemonobenzylether. No changes in the phenoloxidase activity and in the morphological behaviour of the cells could be detected using Levamisol, prednisolonebisuccinate, siliciumdioxide, and Bleomycin, indicating an immunogenic stimulation or immunosuppressive effect. 4-methylbrenzcatechol is probably transformed into a soluble reaction product by phenoloxidase. It could not clearly demonstrated by the histochemical method, if this substance is used as a true substrate. +-catechine, thiomersal, and D-penicillamine cause strong to complete enzyme inhibition of the phenoloxidase containing cells (POC), which are located in the spleen and gut of the white rat. Hydrochinonemonoethylether, hydrochinonemethylether, and hydrochinonemonobenzylether cause an increased pigment fermentation, but they are not used as substrates for the PO.
