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'Chirality' in keywords Facet   section ZfN Section A  [X]
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2000 (1)
1999 (1)
1994 (1)
1Author    Alfred KlemmRequires cookie*
 Title    Monochiralities Caused by Sexuality  
 Abstract    It is shown how the interaction of sexuality and chirality causes monochiralities of the biosphere. In [1], Rikken and Raupach say: "We show experimen-tally that magnetochiral anisotropy can give rise to an enan-tiomeric excess in a photochemical reaction driven by unpolarized light in a parallel magnetic field, which sug-gests that this effect may have played a role in the origin of the homochirality of life."* Also the fact that outside the tropics the sun goes always to the right (left) on the northern (southern) hemisphere suggests that this effect may, via the sun-dependent growth of organisms, have played a role in the origin of the homochirality of life. 
  Reference    Z. Naturforsch. 55a, 978 (2000); received November 23 2000 
  Published    2000 
  Keywords    Evolution, Sexuality, Chirality 
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 TEI-XML for    default:Reihe_A/55/ZNA-2000-55a-0978_n.pdf 
 Identifier    ZNA-2000-55a-0978_n 
 Volume    55 
2Author    I. D. Ierking1, F. G. Ießelm Ann1, P. Zugenm, H. R2, H. Z. Aschke2, W. Kuczynski3Requires cookie*
 Title    The Origin of the Helical Twist Inversion in Single Component Cholesteric Liquid Crystals  
 Abstract    The cholesteric twist inversion by temperature variation o f a single com ponent thermotropic liquid crystalline system was experimentally investigated and is explained by the partial twisting power model, evaluating the temperature dependent pitch o f five different configurations of a benzoic acid biphenyl ester with two chiral centers. The temperature dependence o f the twisting power and the cholesteric pitch for several stereoisomeric com pounds can in first approximation be predicted by the partial twisting powers of the individual chiral centers determined from the partially racemic configurations. 
  Reference    Z. Naturforsch. 49a, 1081—1086 (1994); received August 12 1994 
  Published    1994 
  Keywords    Liquid crystal, Chirality, Cholesteric mesophase, Twist inversion 
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 TEI-XML for    default:Reihe_A/49/ZNA-1994-49a-1081.pdf 
 Identifier    ZNA-1994-49a-1081 
 Volume    49 
3Author    Reiner Memmer, Folkert JanssenRequires cookie*
 Title    Computer Simulation of Chiral Liquid Crystal Phases IX. Chiral Induction in Guest-host Systems - Calculation of the Helical Twisting Power  
 Abstract    The chiral induction in liquid crystalline phases was studied by Monte Carlo simulation of the chiral Lebwohl-Lasher model. Binary guest-host systems composed of achiral and chiral molecules as well as of different chiral molecules were investigated in dependence on the composition. A cholesteric phase was induced by dissolving a small fraction of chiral molecules in a nematic phase. For dilute solutions the equilibrium pitch was found to be a linear function of the chiral dopant concentration. Independent of system size effects the application of self-determined boundary conditions enabled the determination of the symmetry adapted quantities for the chiral induction, the helical twisting power (HTP) and the achiral helical twisting power (AHTP). Additionally, a different orientational behaviour of enantiomer-ic dopants in the chiral surroundings of a cholesteric host phase has been determined. 
  Reference    Z. Naturforsch. 54a, 747—754 (1999); received October 29 1999 
  Published    1999 
  Keywords    Chirality, Liquid Crystals, Computer Simulation, Induced Cholesteric Phases, Helical Twisting Power 
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 TEI-XML for    default:Reihe_A/54/ZNA-1999-54a-0747.pdf 
 Identifier    ZNA-1999-54a-0747 
 Volume    54