Abstract: The invention relates to optical elements having image-forming, color- and polarization-selective reflection and containing cholesteric liquid crystals, and to the preparation and use of these elements. In the wavelength- and polarization-selective elements which form an optical image, at least one cholesteric liquid crystal is enclosed in the cavity of constant thickness between two light-transmitting substrates having curved surfaces in such a way that the helix axis of the liquid crystal is aligned perpendicular to the curved surface of the light-transmitting substrates. The elements are suitable for use as beam splitters or recombiners in projection displays.

Abstract: A composition for the delocalized marking of articles, which makes the forging or improper use or exploitation of these articles difficult. It includes chemical elements having a K.sub..alpha. line of from 3.69 keV to 76.315 keV in defined distributions, the physical properties of these substances and/or their elemental and/or quantitative composition serving as delocalized information which cannot be discerned with the naked eye.

Abstract: Acylated cyclodextrins of the formula I: ##STR1## where R denotes hydrogen or R1, and R1 is identical or different and denotes acetyl, propionyl, butyryl, 2-alkoxyacetyl, 2-chloroacetyl, 2-fluoroacetyl, 2-N-acetylaminoacetyl, methacryloyl or acryloyl, and the DS for R1, measured by means of .sup.1 H NMR spectroscopy, is between 0.3 and 2.0.

Abstract: 4-Hydroxyphenyl benzoate derivatives of the general formula 1: ##STR1## are prepared by cleaving 1,4-bis(benzoyl)hydroquinone derivatives of the general formula 2: ##STR2## with alkali metal alkanolates, in which in the general formulae 1 and 2 R.sup.1 to R.sup.14 are as defined in claim 1.

Abstract: Polymerizable liquid-crystalline siloxanes of a defined composition which are distinguished by low viscosity and pronounced thermochromic properties. The liquid-crystalline siloxanes of the present invention are used for the production of membranes in the optical display of electromagnetic field, opto-electronics, information storage and in particular in the production of optical filters and reflectors.

Abstract: A process for preparing amino-functional cyclodextrin derivatives has an amino function which is linked to the cyclodextrin (CD) via a spacer. Compositions containing CD derivatives are prepared by this process. In this process, .alpha.-cyclodextrin, .beta.-cyclodextrin or .gamma.-cyclodextrin, or their partially substituted derivatives, is reacted individually or in arbitrary mixture with at least one cyclic carbamic ester. The CD derivatives, as regards the listed amino substituents, have an average degree of molar substitution per anhydroglucose unit (MS) of 0.01-0.2 and a proportion of monoamino-substituted CD derivatives which is greater than 70%.

Abstract: The invention relates to catalysts for the catalytic post-combustion of exhaust gases containing carbon monoxide and/or oxidizable organic compounds and processes for their production. The catalysts contain 70 to 99% wt., calculated as TiO.sub.2, of a titanium oxide component, 1 to 30% wt., calculated as V.sub.2 O.sub.5 of a vanadium oxide component and 0.01 to 0.9% wt., calculated as noble metal, of a noble metal component from one or more nobel metal compounds of nobel metals of the 8th sub-group. The catalysts are characterized by a low starting (.ltoreq.220.degree. CC.) and operating temperature and their ability to oxidize even slight pollution of the exhaust gas with oxygen-containing or free aliphatic and aromatic hydrocarbons and carbon monoxide in the presence of gases containing molecular oxygen almost quantitatively to the substantially ecologically acceptable products carbon dioxide and water.

Abstract: A cyclodextrin glycosyltransferase (CGTase) which, in the conversion of starch or starch-like substrates to CD, produces .gamma.-CD in an increased amount, and whose protein sequence, in the region between amino acid position 180 and amino acid position 240, contains the amino acid sequence (SEQ ID NO: 1), where position 1 of the protein sequence is the beginning of the signal peptide of the CGTase and Xxx denotes a natural amino acid.

Abstract: Organosilsesquioxanes having at least one mesogenic side group and processes for their preparation, which comprise reacting organosilsesquioxanes having at least one Si-bonded hydrogen atom with chiral or achiral mesogenic compounds containing an aliphatic multiple bond.

Abstract: The invention rleates to .gamma.-cyclodextrin glycosyl transferases obtainable by screening bacteria for the secretion of a .gamma.-cyclodextrin glycosyl transferase, the bacteria are characterized and the .gamma.-cyclodextrin glycosyl transferase of the bacteria is purified and characterized biochemically. These enzymes can be used for the production of .gamma.cyclodextrin from starch.

Abstract: A compound of the general formulaM--(CH.sub.2).sub.n --(O).sub.m --[--D--B--].sub.q --Y, (I)in which M represents a silicon radical having 2 to 5 silicon atoms which are linked together by bridging elements A, and the remaining valencies of the silicon atoms are saturated with radicals R; A is a bridging element selected from the group consisting of C.sub.1 - to C.sub.8 -alkylene radicals and oxygen with the proviso that at least one radical A per M radical is a C.sub.1 - to C.sub.8 -alkylene radical; R represents optionally fluorine or chlorine atom- or cyano group-substituted straight-chain C.sub.1 - to C.sub.10 -alkyl or C.sub.2 - to C.sub.10 -alkenyl radicals, branched chain C.sub.3 - to C.sub.10 -alkyl or C.sub.3 - to C.sub.10 -alkenyl radicals, optionally C.sub.1 - to C.sub.4 -alkyl- , C.sub.1 - to C.sub.4 -alkoxy radicals, fluorine, chlorine, bromine atom, cyano, trifluoromethyl or nitro radical substituted C.sub.6 - to C.sub.12 -cycloalkyl, C.sub.6 - to C.sub.12 -cycloalkenyl, C.sub.6 - to C.sub.

Abstract: Purple membrane preparations having an increased holographic diffraction efficiency. The purple membrane preparations have a diffraction efficiency of less than 5 seconds and a resolution of greater than 1,500 lines/mm. The purple membrane preparations are obtainable by adjusting a purple membrane suspension having a photocycle time of at least 10 ms to a pH of between 6 and 11 by means of a buffer, adding from 1% to 10% by weight of a proton donor to this purple membrane suspension, and drying the resultant suspension down to a water content of from 1% to 30% by weight.

Abstract: The invention relates to pigments whose color depends on the viewing angle, their preparation and use.These pigments comprise oriented three-dimensionally crosslinked substances of liquid-crystalline structure having a chiral phase and, if desired, further dyes and pigments, the further dyes and pigments if present not serving as base for the oriented three-dimensionally crosslinked liquid-crystalline substances having a chiral phase.

Abstract: The invention relates to optical elements based on liquid-crystalline substances, and to a process for the production thereof. The optical elements based on liquid-crystalline substances are ones which exhibit no birefringence in a defined direction of incidence, optical elements in which no birefringence occurs perpendicularly to the surface being excepted. The process for preparing the optical elements comprises illuminating a liquid-crystalline substance with unpolarized light of suitable wavelength at a defined angle in such a way that, after illumination, the director of this substance is aligned parallel to the direction of the illuminating light on passing through said substance.

Abstract: A hydrophilic, water-dilatable cyclodextrin polymerizate has a high cyclodextrin content which possesses good mechanical properties. The cyclodextrin pearl polymerizates are produced by radical, inversion suspension polymerization of cyclodextrin derivatives carrying methacrylate groups or their copolymerization with suitable comonomers such as hydroxyethylacrylate or hydroxymethylacrylate. Suitable cyclodextrin derivatives can be produced by reacting cyclodextrins or hydroxyalkyl cyclodextrins with methacrylic anhydride or with glycidyl methacrylate. The cyclodextrin polymerizates produced in this manner have mechanical properties appreciably superior to those of known, comparable cyclodextrin polymers.

Abstract: The present invention provides a process for the preparation of optically active carboxylic acids of the formula I* or II* ##STR1## in which X is an oxygen or sulfur atom and n is 1 or 2. The process comprises reacting a racemic carboxylic acid I or II or its derivatives with an optically active 2-amino-carboxylic acid ester to give the diastereomeric carboxylic acid amides, separating the diastereomers and, after cleavage of the amide bond, isolating the optically active carboxylic acids of the general formula I* or II*. The invention also provides certain novel optically active carboxylic acid amides and a tetrahydrothiopyran-2-carboxylic acid.

Abstract: Novel tetrasubstituted methane derivatives of the general formula C[--Sp--M--R].sub.4 in which the radicals --Sp--M--R are the same or different, in which Sp is a spacer group selected from an alkylene or alkenylene radical which is unsubstituted or monosubstituted by halogen, --CN or --CF.sub.3 or one or two non-adjacent CH.sub.2 groups may be replaced by --O--, --CO--, --COO--, --OOC--, --CONH-- or --OCOO--, or is a single bond; R is selected from hydrogen, halogen, --CN, --CF.sub.3, --OCF.sub.3, --NO.sub.2, --N(CH.sub.3).sub.2, an alkyl or alkenyl radical which is unsubstituted or monosubstituted or polysubstituted by --CN, --NH.sub.2, --CF.sub.3 or halogen and in which one or more non-adjacent CH.sub.2 groups may be replaced by the radicals --O--, --CO--, --OOC--, --COO-- or OCOO--; and M is a mesogenic group. Due to their liquid crystal properties, the novel compounds are eminently suitable for use in liquid crystalline media.

Abstract: The present invention relates to cyclic siloxanes which have at least one group of formula (1) bonded to a silicon atom--(CH.sub.2).sub.x --R"--[--L--A--].sub.y --(L).sub.z --T (1),in which x is an integer having a value of at least 2, preferably having a value of from 2 to 10, R" is a chemical bond or a divalent radical of the formula --COO--, --OOC--, --CH.sub.2 --CH.sub.2 --, --CH.dbd.CH--, --C.tbd.C--, --N.dbd.N--, --N.dbd.N, --N.dbd.CH--, --CH.dbd.N or --Si(R).sub.

Abstract: The alkalophilic bacteria (DSM 5853) possesses a maltopentaose producing amylase. The maltopentaose producing amylase, and its derivatives modified by gene manipulation, can be expressed in E. coli. These amylases facilitate the production of maltopentaose.

Abstract: The invention relates to optical elements based on helical liquid-crystalline substances, having reflection bands of linear-polarized light, and to a process for preparing the same. The optical elements of this invention contain only one optically effective component based on helical liquid-crystalline substances. They reflect light incident perpendicular to the surface in a linear-polarized manner parallel to the direction of incidence of the incident light. The process for preparing the optical elements comprises illuminating a helical liquid-crystalline substance which contains at least one photoisomerizable substance with linear-polarized light in such a manner that this substance is subsequently aligned so that it exhibits at least one reflection band of linear-polarized light on illumination. Suitable helical liquid-crystalline substances are in particular organopolysiloxanes. The optical elements are suitable, for example, for data storage.