Pinhole hologram and its applications

We propose the use of a pinhole-camera approach to make holograms. On recording the object beam passes through a pinhole, forming an image plane hologram, but on reconstruction the pinhole can be taken away. The reconstructed image can be programmed and processed by using optical information-processing elements placed in the position of the reconstructed pinhole or pinholes. Pinhole holography can also suppress intermodulation effects. We present brief theoretical considerations and experimental results for pinhole holograms produced for programmable holographic optical interconnects.

Deep-red holography using a junction laser and silver-halide holographic emulsion

We have investigated exposure parameters for deep-red holography using a junction laser and silver-halide holographic emulsion to record single-beam reflection phase-volume holograms recorded and reconstructed at a wavelength of 750 nm. We present measurements of the variation of diffraction efficiency and its derivative efficiency with exposure energy. These measurements are compared with the corresponding values obtained when using a He-Ne laser for recording; similar diffraction efficiencies have been obtained with both kinds of laser.

Dynamic properties of membrane proteins: reversible insertion into membrane vesicles of a colicin E1 channel-forming peptide

The binding of colicin E1 and its COOH-terminal channel-forming peptides to artificial membrane vesicles has an optimum at acidic pH values. The Mr 18,000 thermolytic peptide inserted into membrane vesicles at pH 4.0 has a limited accessibility to exogenous protease. It is converted by trypsin cleavage after Lys-381 and Lys-382 to a lower Mr 14,000 peptide. However, when the pH of a vesicle suspension to which peptide has been bound at pH 4.0 is shifted to 6.0, the accessibility to protease increased greatly. This was shown (i) by the large decrease in the amount of Mr 14,000 or Mr 18,000 peptide after the pH 4----6 shift and treatment with trypsin or Pronase, consistent with (ii) a previously observed decrease in membrane-bound radiolabeled peptide after protease treatment. (iii) When a photoactivable nitrene-generating phospholipid probe was used to label the colicin peptide inserted into the bilayer, the extent of labeling decreased by a factor of 3 when the pH was shifted from 4.0 to 6.5. (iv) Colicin peptide added to vesicles at pH 4.0 can "hop" to other vesicles if the pH and ionic strength of donor vesicles are successively increased. It is proposed that deprotonation of acidic residues in contact with the hydrophobic bilayer or the membrane surface destabilizes the inserted channel and causes it to be extruded from the membrane. The pH-dependent extrusion of the inserted colicin channel provides an example of dynamic properties of an intrinsic membrane protein.

Sympathetic ophthalmia. An immunohistochemical study of epithelioid and giant cells

There is controversy regarding the origin of the pigment-containing epithelioid cells in the uvea of eyes with sympathetic ophthalmia. The results of the present immunocytochemical study demonstrating the presence of muramidase and S-100 protein in these cells, and the binding of peanut lectin by the pigment-containing cells support the interpretation that the pigment-containing epithelioid cells and giant cells are of monocytic (histiocytic) origin. Our study also emphasizes the diverse functional capacity of these epithelioid cells.

Culture requirements of Ascaris suum larvae using a stationary multi-well system: increased survival, development and growth with cholesterol

Ascaris suum third-stage larvae (L3) were recovered from infected rabbits and cultured in a stationary multi-well plate system. Several different culture media including Medium 199, NCTC-135, Minimum Essential Medium-Eagle, Dulbecco's Modified Eagle's Medium, RPMI 1640, McCoy's 5A and Neuman-Tytell medium were tested to determine which was best for overall larval survival, development and growth. Larvae developed from L3 to fourth-stage (L4) in all media tested, but larval survival and the yield and growth of L4 were superior in RPMI 1640. Pyruvate is an important medium component because its addition to RPMI 1640 enhanced the yield and growth of L4 while its removal from DMEM reduced larval survival and the yield and growth of L4. Cholesterol markedly enhanced larval survival and the yield and growth of L4 when added to RPMI 1640 as either a soluble supplement in Tween 80 or to a lesser degree, as a component of liposomes. The multi-well culture plate system is a convenient method for determining the effects of different media and changes in media composition on larvae in vitro.