Abstract: Ferroelectric liquid crystal mixtures containing compounds of the formula (I): ##STR1## wherein R.sup.1 is, for example, a straight-chain or branched alkyl radical having 1 to 22 carbon atoms, in which one --CH.sub.2 -- group may be replaced by --O-- or --CO--O--.

Abstract: Optically active 1,3-dioxolane derivatives which carry a mesogenic radical in the 4-position and have the general formula (I) ##STR1## are suitable for use as doping agents in liquid-crystal mixtures--in particular ferroelectric liquid-crystal mixtures. The symbols in the general formula have the following meanings:R.sup.1 is composed analogously to the part of the general formula on the right-hand side of X or is an alkyl or alkylene radical which can be substituted,R.sup.2, R.sub.3 and R.sup.4 are H or alkyl (R.sup.4 is also alkenyl) which can also be substituted [R.sup.2 and R.sup.3, together with the C(2) of the dioxolane ring are also a cycloaliphatic radical or a keto group], J, l and n are zero, 1 or 2 and k and m are zero or 1, subject to the proviso that, if k is zero n is zero and if n is zero m is zero and 1.ltoreq.J+l+n.ltoreq.3,--A.sup.1, --A.sup.2 and --A.sup.3 are an aromatic, heterocyclic or aliphatic ring system, --M.sup.1 and --M.sup.2 are --CO--O, --0--CO, --CH.sub.2 CH.sub.2, --CH.dbd.

Abstract: Optically active, mesogenic 1,3-dioxolane-4-carboxylates are suitable as dopes in liquid-crystal mixtures. They result in liquid-crystalline ferroelectric phases having short switching times and in electroclinic phases having large electroclinic coefficients. Their particular advantage is that they induce a helix of very large pitch, meaning that helix compensation by further dopes is unnecessary. In addition, the 1,3-dioxolane-4-carboxylates exhibit high UV stability.

Abstract: Ferroelectric liquid-crystal systems having high spontaneous polarization, in particular >35 nC cm.sup.-2, and good orientation properties in the ferroelectric phase, in particular the S.sub.C * phase, contain at least three different optically active compounds, preferably as dopes in a base mixture which is not itself optically active and has a nematic phase above the smectic phase. The optically active compounds are selected so that they do not all induce a helix of the same rotation sense in the nematic phase. Their relative concentrations are selected so that the total resultant pitch of the helix throughout the cholesteric phase is not less than 10 .mu.m.

Abstract: Cyclohexylphenylpyrimidines of the formula (I) ##STR1## in which R.sup.1 is straight-chain or branched, chiral or achiral alkyl or alkenyl having 2 to 16 carbon atoms, in which one or two nonadjacent --CH.sub.2 -- groups may be replaced by --0--, --S--, --CO--, --COO--, --OCO--, --Si(CH.sub.3).sub.2 -- or --C(CH.sub.3).sub.2 --, and in which one or more hydrogen atoms of the alkyl or alkenyl radical may be replaced by fluorine atoms, and in which the terminal CH.sub.3 group of the alkyl may also be replaced by ##STR2## R.sup.2 is straight-chain or branched, chiral or achiral alkyl having 1 to 10 carbon atoms,are particularly suitable components for ferroelectric liquid-crystal mixtures since they result in favorable properties, such as, for example, high contrast, when used in electrooptical switching and display devices.

Abstract: An H. saimiri-HTLV-1 or 2 X region vector is disclosed. This vector can be used to establish continuous cell lines of difficult to grow cells, such as human T-cells. It can also be used to obtain certain cell products and in methods for screening new compounds.

Abstract: Disclosed and claimed are liquid-crystalline cyclopropylalkyl or -alkenyl or heterocyclic compounds, process for their preparation, and their use in liquid-crystalline mixtures. The novel cyclopropylalkyl or -alkenyl or heterocyclic compounds are of the general formula ##STR1## In this formula A.sup.1, A.sup.2 and A.sup.3 are unsubstituted or substituted, aromatic or heteroaromatic molecular components such as 1,4-phenylene or pyrimidine-2,5-diyl which are linked via a single bond (in the case where k and m=0) or via functional groups M.sup.1 and M.sup.2, such as CO--O or CH.sub.2 --O; j, k, l, m and n are zero, 1 or 2. The radicals R.sup.2, R.sup.3 and R.sup.4 are H or alkyl/alkenyl, R.sup.1 is alkyl/alkenyl or one of the substitutents known from LC chemistry such as an .alpha.-haloalkanoic acid radical. At least one of the components A.sup.1, A.sup.2 and A.sup.3 can be heteroaromatic, and G is alkylene or alkenylene.

Abstract: The use of optically active tetrahydrofuran-2-carboxylic acid esters as dopants in liquid-crystal mixtures, liquid-crystal mixtures containing same and novel optically active tetrahydrofuran-2-carboxylic acid esters.Optically active tetrahydrofuran-2-carboxylic acid esters containing a mesogenic molecular building unit are suitable as dopants in liquid-crystal mixtures. They result in liquid-crystalline ferroelectric phases having short switching times and in electroclinic phases having large electroclinic coefficients. A further advantage is that they induce a helix having a very small pitch so that they are also suitable for helix compensation in LC mixtures.The compounds are symbolized by the general formula: ##STR1## in which the symbols and indices essentially denote: R.sup.1 =alkyl/alkenyl or tetrahydrofurancarbonyloxy or -thio; j, l, n=zero, 1 or 2; k, m=zero or 1; --A.sup.1, --A.sup.2, --A.sup.3 =phenylene, cycloalkylene or corresponding heterocyclates containing nitrogen, oxygen or sulfur; --M.sup.

Abstract: The novel ferroelectric liquid-crystalline mixtures are based on at least two mixture components of the general formula (I) ##STR1## but additionally contain at least one optically active dope from one or more of the following groupsa) optically active esters of tetrahydrofuran-2-carboxylic acidb) optically active aryl 2,3-epoxyalkyl ethersc) optically active 1,3-dioxolan-4-yl ethers.The ferroelectric LC mixtures have a high spontaneous polarization and facilitate substantial compensation of the pitch of the helix in a nematic phase.

Abstract: Geminal dimethylalkyl compounds, process for their preparation and their use in liquid-crystalline mixtures Geminal dimethylalkyl compounds of the formula (I) ##STR1## in which: R.sup.1 is, for example, straight-chain or branched (with or without an asymmetric carbon atom) alkyl or alkenyl having 2 to 16 carbon atoms,A.sup.1, A.sup.2 and A.sup.3 are, for example, identical or different 1,4-phenylene, 1,4-cyclohexylene or pyrimidine-2,5-diyl,M.sup.1 and M.sup.2 are, for example, identical or different CO--O or O--CO,G is for example, identical or different straight-chain or branched alkylene having 1 to 16 carbon atoms,k, l, m and n are zero or 1, andR.sup.6 is straight-cain alkyl having 1 to 10 carbon atoms,can advantageously be employed in liquid-crystalline mixtures. In liquid-crystalline mixtures, said compounds result in a melting point depression, in a shift in the temperature limit of the S.sub.c phase in ferroelectric mixtures and in other improvements of important electrooptical characteristic values.

Abstract: Use of optically active carboxylic esters of oxygen-containing heterocycles as doping substances in liquid crystal mixtures and liquid crystal mixtures containing them.Optically active 1,3-dioxolane-4-carboxylic esters and oxirane-2-carboxylic esters of the general formula (I)R(--A.sup.1).sub.j (--M.sup.1).sub.k (--A.sup.2).sub.l (--M.sup.2).sub.m (--A.sup.3).sub.n --X--Acin whichR.sup.1 is, for example, (C.sub.1 -C.sub.16)-alkyl or (C.sub.1 -C.sub.16)-alkoxy,A.sup.1, A.sup.2, A.sup.3 are, for example, phenyl or pyrimidine-2, 5-diyl,M.sup.1, M.sup.2 are, for example, CO--O, CH.sub.2 --CH.sub.2,j, l are 0, 1, 2,k, m are 0, 1,n is 0, 1, 2,X is O, S andAc is ##STR1## in which R.sup.2, R.sup.3, R.sup.4, R.sup.5, R.sup.6 for example, H or methyl, are particularly suitable doping substances for liquid crystalline mixtures, since they induce a high spontaneous polarization and effect a substantial decrease in the melting point.

Abstract: The novel silylalkyl or silylalkenyl compounds correspond to the general formula (I) ##STR1## Here the symbols A.sup.1, A.sup.2, A.sup.3 denote aromatic or heteroaromatic molecular units such as 1,4-phenylene or pyrimidine-2,5-diyl which are combined via a single bond (for k, m=0) or via functional groups M.sup.1,M.sup.2 such as CO--O or CH.sub.2 --O; j, k, l, m, n are zero or 1 (j+l+n=2 or 3). The radicals R.sup.2, R.sup.3, R.sup.4, R.sup.5 are hydrogen or alkyl/alkenyl, cycloalkyl, and the radicals R.sup.6, R.sup.7, R.sup.8 have a comparable meaning (hydrogen); R.sup.1 is alkyl/alkenyl or one of the substituents known from LC chemistry such as an .alpha.-haloalkanoic radical. In some cases compounds have wide and polymorphous liquid crystalline phases.

Abstract: Optically active 1,3-dioxolane derivatives of the general formula (I) ##STR1## are suitable as doping substances in liquid crystal mixtures. The symbols in the general formula have the following meaning:R.sup.1 has the structure which is analogous to the moiety of the general formula which is on the right of X or is an alkyl or alkylene radical which can be substituted, R.sup.2, R.sup.3 are H or alkyl, which can also be substituted [R.sup.2, R.sup.3 can also be a cycloaliphatic compound together with C(2) of the dioxolane ring],R.sup.4 is vinyl or ethyl, with the proviso that at least one radical R.sup.4 is vinyl or ethyl, if R.sup.1 is analogous to the moiety of the formula (I) which is on the right of X, --A.sup.1, --A.sup.2, --A.sup.3 are an aromatic, heterocyclic or aliphatic ring system,--M.sup.1, --M.sup.2 are --CO--O, --O--CO, --CH.sub.2 CH.sub.2, --CH.dbd.CH, --CH.sub.2 O, --OCH.sub.2, --C.dbd.C andX is O, S or O--CO--O.

Abstract: The novel liquid-crystalline mixtures (in the case of ferroelectric behavior they additionally contain an optically active compound as dope) are based on at least two mixture components of the general formula (I) and at least one carboxylate of the general formula (II), (III) or (IV). ##STR1## The mixtures have favorable properties for use in electrooptical display elements, such as high contrast, low melting point and short switching times.

Abstract: Cyclohexylphenylpyrimidines of the formula (I) ##STR1## in which R.sup.1 is straight-chain or branched, chiral or achiral alkyl or alkenyl having 2 to 16 carbon atoms, in which one or two nonadjacent --CH.sub.2 -- groups may be replaced by --O--, --S--, --CO--, --COO--, --OCO--, --Si(CH.sub.3).sub.2 -- or --C(CH.sub.3).sub.2 --, and in which one or more hydrogen atoms of the alkyl or alkenyl radical may be replaced by fluorine atoms, and in which the terminal CH.sub.3 group of the alkyl may also be replaced by ##STR2## R.sup.2 is straight-chain or branched, chiral or achiral alkyl having 1 to 10 carbon atoms,are particularly suitable components for ferroelectric liquid-crystal mixtures since they result in favorable properties, such as, for example, high contrast, when used in electrooptical switching and display devices.

Abstract: In a process of producing strip or wire, which consists of a monotectic aluminum-silicon alloy comprising a matrix consisting of aluminum and an aluminum-silicon eutectic system and as a minority phase 1 to 50% by weight lead or bismuth included in said matrix, which strip or wire has been continuously cast at a high casting velocity and a high cooling rate from a molten material which has been heated to a temperature above the segregation temperature, and which strip or wire has been subjected to plastic deformation and to a heat treatment, the minority phase which is embedded in the form of elongate platelets in the strip or wire is transformed to more compact shapes by a heat treatment at temperatures of 550.degree. to 600.degree. C.

Abstract: The novel liquid-crystalline mixtures (in the case of ferroelectric behavior they additionally contain an optically active compound as dope) are constructed from at least 2 mixture components of the general formula (I): ##STR1## wherein n=6 to 14 and x=2 to 14. In addition, the mixtures may also contain cyclohexanecarboxylates of the general formula (II) ##STR2## where R.sup.1 =(C.sub.10 -C.sub.16) or (C.sub.8 -C.sub.14)alkoxy and R.sup.2 =(C.sub.2 -C.sub.9)alkyl, alkenyloxyphenylpyrimidine derivatives of the general formula (III) ##STR3## where R.sup.3 =(C.sub.7 -C.sub.16)alkyl or (C.sub.6 -C.sub.14)alkoxy and y=4-14, and/or alkoxyphenyl derivatives of alkylpyrimidine, of the general formula (IV) ##STR4## where m and p=6 to 14.

Abstract: Optically active oxirane-2-carboxylic acid esters with a mesogenic molecular component suitable as dopants in liquid-crystal mixtures. They result in liquid-crystalline ferroelectric phases with short switching times and in electroclinic phases with large electroclinic coefficients. A further advantage lies in the fact that they induce a helix with a very small pitch so that they are also suitable for helix compensation in LC mixtures.

Abstract: Arylcarboxylates of 2-hydroxypropionates are known, amongst other compounds, as dopes for converting tilted smectic liquid-crystal phases into ferroelectric liquid-crystal phases.The novel chiral aryloxypropionates of the general formula ##STR1## are two-fold chiral and in which the symbols have the following meaning: R.sup.1 denotes a straight-chain alkyl or alkoxy radical having 1 to 16 carbon atoms or a branched alkyl or alkoxy radical having 4 to 16 carbon atoms, it being possible for one or two non-adjacent CH.sub.2 groups to be replaced by a sulfur and/or oxygen atom;A denotes one, two or three aromatic or heteroaromatic rings which are linked to one another directly or via one or two COO groups;B denotes a chemical bond or one or two aromatic or heteroaromatic rings which are linked directly to one another;R.sup.2(a) if B is a chemical bond, denotes an alkyl radical having 2 to 10 carbon atoms which contains an asymmetrical carbon atom which is substituted by CH.sub.3, halogen or a COOC.sub.2 H.sub.

Abstract: Liquid-crystal 5-phenylpyrmidine derivatives having S.sub.c or S.sup.*.sub.c phases and a process for preparing them. The new liquid-crystal 5-phenylpyrimidine derivatives have an S.sub.c or S.sup.*.sub.c phase and are described by the general formula (I) ##STR1## in which the symbols have the following meaning: R.sup.1 and R.sup.2 denote identical or different, straight-chain or branched alkyl or alkenyl groups having from k to 16 carbon atoms, with or without an asymmetric carbon atom, in which one or more non-adjacent --CH.sub.2 -- groups can be replaced by --O-- and /or --S----A and --B each denote ##STR2## in which the radicals R.sup.1, R.sup.2, in each case, are situated at the phenylene part of --A, --B andm and n denote 0 or 1, but m and n do not simultaneously denote 1, with the following provisos:(a) if m=n=0, k is 8, and in R.sup.2 the --CH.sub.2 -- group adjacent to the phenyl nucleus is replaced by --O--;(b) if m=1 and n=0, k is 2, and(c) if m=0 and n=1, k is 2 and in R.sup.2 the --CH.sub.