Origin of asymmetry

An X-ray structure of the major diastereomeric complex was also obtained to give further insight into the origin of asymmetry in the attack by nucleophiles.446... 

Gillard R.D. and da Luz de Jesus J.D.P. (1979) Studies on the origin of asymmetry. Part I. Optieally aetive erystals as selective adsorbents, J. Chem. Soc., Dalton Trans. 1779-1782. 

Chris McManus, Right Hand, Left Hand The Origins of Asymmetry in Brains, Bodies, Atoms and Cultured , Harvard University Press, 2002. 

The origin of asymmetry of biomolecules Combination of deterministic and stochastic models ... 

Fig.40 Schematics illustrating the origin of asymmetry in the I-V curves and energy levels. (Reproduced with permission from Ref [159])...

One may say in summary that of the four origins of asymmetry in polyisocyanides discussed above, only one is predicated to be induced, i.e., the nickel(II)-catalyzed (but not the sulfuric acid catalyzed) polymerization of chiral monomers. The other three are reasoned to be autogenic. One may expect that polyiso-... 

Coren, S., The Left-Hander Syndrome The Causes and Consequences of Left-Handedness, Vintage Books (Random House), New York, 1993. McManus, C., Right Hand, Left Hand The Origins of Asymmetry in Brains, Bodies, Atoms and Cultures, Harvard Univ. Press, Cambridge, MA, 2004. Annett, M., Handedness and Brain Asymmetry The Right Shift Theory, Psychology Press, 2002. 

J, J. Halliwell, J. Perez-Mercader, and W. H. Znrek, eds.. Physical Origin of Time Asymmetry, University Press, Cambridge, 1994. 

Fig. 2.2. Origin of facial selectivity in indolylmethyloxazaborolidinone structure. Reproduced from Tetrahedron Asymmetry, 9, 357 (1998), by permission of Elsevier. (See also color insert.)...

In comparison to the research in n-type oxide semiconductors, little work has been done on the development of p-type TCOs. The effective p-type doping in TCOs is often compensated due to their intrinsic oxide structural tolerance to oxygen vacancies and metal interstitials. Recently, significant developments have been reported about ZnO, CuA102, and Cu2Sr02 as true p-type oxide semiconductors. The ZnO exhibits unipolarity or asymmetry in its ability to be doped n-type or p-type. ZnO is naturally an n-type oxide semiconductor because of a deviation from stoichiometry due to the presence of intrinsic defects such as Zn interstitials and oxygen vacancies. A p-type ZnO, doped with As or N as a shallow acceptor and codoped with Ga or Zn as a donor, has been recently reported. However, the origin of the p-type conductivity and the effect of structural defects on n-type to p-type conversion in ZnO films are not completely understood. 

Becker, P. Evolution in open systems Bistability and the origin of molecular asymmetry, Nature New Biology 241, 72—74 (1973). 

When a racemic substance is hydrogenated or when the reduction leads to the production of centers of asymmetry, the phytochemical reduction will take at first a completely or partially asymmetric course. Examples of such asymmetric reactions are the conversions of pure racemic valeraldehyde, acetaldol, furoin and furil, diacetyl and acetyl-methylcarbinol to optically active alcohols. Occasionally meso forms also arise, as for example in the case off glycols (p. 84). The reasons for the stereochemical specificity of these reactions have not been clarified. This type of phenomenon has frequently been observed in the related intramolecular dismutation of keto aldehydes, especially if enzyme materials of differing origins are used. 

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