Liquid Pressure Varifocus Lens

A liquid pressure varifocus lens that consists of a thin polymer film and liquid is described. The lens can be continuously changed from a concave to a convex shape by driving the liquid pressure in the lens. The dynamic range of the focal length of the convex lens is from 50 to 250 mm. A beam spot verifies the variable focal function on a photographic film exposed by a He-Ne laser. In addition, the application of the laser for processing is demonstrated to manufacture Fe compressed powder sheets by normal pulse YAG laser. Its melting marks along a focus change are formed with a minimum width of 0.1 mm.     

THE PHOTOREACTIONS AND PHOTOSENSITIVITY OF 3,4-DEHYDRO-BACTERIORHODOPSIN AT LOW TEMPERATURES

Abstract— The photoreaction of the artificial pigment synthesized from bacterioopsin and rrans-3,4-dehydro-retinal, [3,4-dehydro]bacteriorhodopsin ([3,4-deH]bR^t) was investigated with low temperature spectrophotometry.
The amount of batho-product formed from the light-adapted pigment of [3,4-deH]bR (designated as batho-[3,4-deH]bR^t) by irradiation at 77 K was much less than that from trans -bacteriorhodopsin (bR^t) and depends on temperature at irradiation of the sample. The kinetics of photoconversion of [3,4-deH]bR^t to batho-[3,4-deH]bR^t and that of its reversion were measured at several temperatures with a so-called "double Dewar system". The results showed that the photosensitivity of [3,4-deH]bR^t was temperature dependent. When batho-[3,4-deH]bR^t was warmed above 143 K, it was converted to lumi-[3,4-deH]bR^t. Lumi-[3,4-deH]bR^t was also produced by irradiation of [3,4-deH]bR^t at 143 or 163 K. The maximum in the difference spectrum between lumi-[3,4-deH]bR^t and [3,4-deH]bR^t was located at about 540 nm. The irradiation of [3,4-deH]bR^t at 183 K produced an intermediate analogous to meta-bR^t, but under similar conditions bR^t does not produce meta-bR^t. These results indicate that intermediates of [3,4-deH]bR^t are less stable than those of bR^t.
The differences between bacteriorhodopsin and [3,4-dehydro]bacteriorhodopsin were discussed and compared with the differences between rhodopsin and [3,4-dehydro]rhodopsin.     

Thermally Stable and Resonance Enhanced Large Nonlinear Optical Properties In Poled Silica Films Doped with Thiazole Azo Dye

Sol-gel processed poled silica films doped with novel nonlinear organic materials, thiazole azo dye (TA), are prepared in high concentration. Resonance enhanced second-order nonlinear optical coefficient of d₃₃ = 154 pm/V is obtained from TA doped silica film (40 wt%) for the fundamental wavelength of 1064 nm. The value d₃₃ is unvaried for at least 100 h under a high temperature condition (100°C) without any relaxation. Wavelength dependent second-order nonlinearity is also measured.     

SPECTROSCOPIC STUDIES ON THE STRUCTURES OF RETINOCHROME and METARETINOCHROME*

Abstract– Spectroscopic measurements of retinochrome and the related photoproduct, metaretino-chrome, were carried out to determine the conformation of the retinal and the protein. Absorption spectra with fourth derivatives indicate that the tryptophan residues are located in a hydrophobic core and that the environment around these residues does not change after light irradiation. Circular dichroism measurements indicate that retinochrome has a high helical content which is not altered by the conversion of retinochrome to metaretinochrome. Fourier transform infrared difference spectra demonstrate that retinochrome has the all-trans retinal and metaretinochrome has the 11-CM retinal. Retinochrome has an absorption due to amino acid residue(s) which changes in metaretinochrome. This work demonstrates that conformational changes are not induced during the conversion but the electrical charge(s) of the protein are changed by irradiation.     

BACTERIORHODOPSIN RECONSTITUTED FROM TWO INDIVIDUAL HELICES AND THE COMPLEMENTARY FIVE-HELIX FRAGMENT IS PHOTOACTIVE

Bacteriorhodopsin (bR), a light-driven proton pump, consists of a bundle of seven membrane-spanning alpha-helices connected to each other by short extramembranous loops. Previously it has been shown that bR can be reconstituted from three fragments corresponding to the first helix, the second helix, and the remaining five helices, and that this reconstituted material reforms the native structure of bR. In this study, it is shown that the native function is also recovered. Low-temperature spectroscopy was used to examine the photochemical properties of bR reconstituted from three fragments. At room temperature at pH 6, the reconstituted material shows essentially the same absorption spectrum as native bR, while upon raising the pH at room temperature or cooling the sample in glycerol, a second, blue-shifted peak appears. The pH and temperature dependence of the absorption spectrum indicates that the reconstituted bR is in an equilibrium between two pigments, which we call P560 and P480. Both pigments convert to their own K intermediates, which differ in absorption maxima, upon illumination with green light at -180 degrees C. Each K intermediate can be reverted to its initial state by light. Similarly, both pigments convert to their own M intermediates upon irradiation with yellow light at -77 degrees C. The M intermediate of both species can be reverted only to P560 by light. Both pigments are therefore photoactive. These unique photochemical properties of bR reconstituted from three fragments may be attributable to the lack of a covalent linkage in the loop connecting the A and B helices, and thus possibly to a change in the orientation of the B helix.     

Modified guanidines as potential chiral superbases. 3. Preparation Of 1,4,6-triazabicyclooctene systems and 1,4-disubstituted 2-iminoimidazolidines by the 2-chloro-1,3-dimethylimidazolinium chloride-induced cyclization of guanidines with a hydroxyethyl substituent

Simple preparation methods of modified guanidines have been explored as potential chiral superbases. Thus, 3,7,8-trisubstituted and 3,6,7, 8-tetrasubstituted 1,4,6-triazabicyclooctene systems were prepared from (1S,2S)-1,2-diphenylethylenediamine through stepwise 2-chloro-1, 3-dimethylimidazolinium chloride (DMC)-induced cyclizations of protected thioureas to the corresponding 2-iminoimidazolidines and then of 2-(2-hydroxyethylimino)imidazolidines to the bicyclic systems. Linear guanidines with a 2-hydroxyethyl functional group were prepared by the reaction of carbodiimides with 2-amino alcohols. Reaction of linear-type guanidines with DMC followed by base treatment afforded 1,4-disubstitued 2-iminoimidazolidines. Furthermore, another type of 1,4,6-triazabicyclooctene was also prepared through double DMC-induced cyclization of guanidines with two 2-hydroxyethyl substituents.     

Ruthenium complex-catalyzed anti-Markovnikov hydration of terminal alkynes

[reaction: see text]. Highly regioselective, efficient, and substituent-tolerant anti-Markovnikov hydration of terminal alkynes occurs to give n-aldehyde by use of a catalytic amount of easily available cyclopentadienylruthenium complexes bearing appropriate bidentate or monodentate phosphine ligands. Typically, RuCpCl(dppm) (1 mol %) catalyzes the addition of water to 1-hexyne at 100 degrees C to give hexanal in 95% yield: 2-hexanone is not detected at all.     

Ruthenium-Catalyzed Intermolecular Hydroamination of Terminal Alkynes with Anilines: A Practical Synthesis of Aromatic Ketimines

Without solvent and in the open air, the hydroamination of phenylacetylene with aniline in the presence of [Ru(3)(CO)(12)]/NH(4)PF(6) proceeds with high regioselectivity [Eq. (1)]. Simple distillation gives a product with greater than 99 % purity in an excellent yield. The application of this method to a new two-component reaction gives the important class of substances: the quinolines.