Asymmetric photolysis of (RS)-leucine with circularly polarized ultraviolet light

1977 ◽  
Vol 99 (11) ◽  
pp. 3622-3625 ◽  
Author(s):  
Jose J. Flores ◽  
William A. Bonner ◽  
Gail A. Massey
Keyword(s):  
Ultraviolet Light ◽  
Circularly Polarized ◽  
Asymmetric Photolysis

scholarly journals Astronomical Sources of Circularly Polarized Light and Their Role in Determining Molecular Chirality on Earth

1985 ◽  
Vol 112 ◽  
pp. 171-175
Author(s):  
Ramon D. Wolstencroft
Keyword(s):  
Polarized Light ◽  
Racemic Mixture ◽  
Relative Importance ◽  
Chiral Molecules ◽  
Direct Sunlight ◽  
Primitive Earth ◽  
Circularly Polarized Light ◽  
Circularly Polarized ◽  
Chiral Selection ◽  
Asymmetric Photolysis

The major source of circularly polarized flux potentially capable of inducing asymmetric photolysis of a racemic mixture of chiral molecules on the primitive Earth is the daytime sky. The degree of circular polarization (q) depends on the slope and orientation of the local terrain which obscures part of the sky. After allowance for dilution by direct sunlight values of |q| range between about 10−4 and 10−5. The rates of (1) asymmetric photolysis, (2) chiral selection by the electro-weak process and (3) racemization are not yet well enough known for the relative importance of these processes to be definitely established.

Production and direct measurement of circularly polarized vacuum‐ultraviolet light with multireflection optics

1991 ◽  
Vol 58 (23) ◽  
pp. 2592-2594 ◽  
Author(s):  
T. Koide ◽  
T. Shidara ◽  
M. Yuri ◽  
N. Kandaka ◽  
H. Fukutani
Keyword(s):  
Ultraviolet Light ◽  
Direct Measurement ◽  
Vacuum Ultraviolet ◽  
Circularly Polarized

The Use of Styrenes as Embedding Media for Electron Microscopy

1971 ◽  
Vol 29 ◽  
pp. 488-489
Author(s):  
Edward D. De-Lamater ◽  
Eric Johnson ◽  
Thad Schoen ◽  
Cecil Whitaker
Keyword(s):  
Electron Microscopy ◽  
Surface Tension ◽  
Ultraviolet Light ◽  
Methyl Ethyl Ketone Peroxide ◽  
Methyl Ethyl ◽  
Styrene Polymerization ◽  
Radical Initiation ◽  
Tertiary Butyl ◽  
Low Viscosity ◽  
Free Radical Initiation

Monomeric styrenes are demonstrated as excellent embedding media for electron microscopy. Monomeric styrene has extremely low viscosity and low surface tension (less than 1) affording extremely rapid penetration into the specimen. Spurr's Medium based on ERL-4206 (J.Ultra. Research 26, 31-43, 1969) is viscous, requiring gradual infiltration with increasing concentrations. Styrenes are soluble in alcohol and acetone thus fitting well into the usual dehydration procedures. Infiltration with styrene may be done directly following complete dehydration without dilution.Monomeric styrenes are usually inhibited from polymerization by a catechol, in this case, tertiary butyl catechol. Styrene polymerization is activated by Methyl Ethyl Ketone peroxide, a liquid, and probably acts by overcoming the inhibition of the catechol, acting as a source of free radical initiation.Polymerization is carried out either by a temperature of 60°C. or under ultraviolet light with wave lengths of 3400-4000 Engstroms; polymerization stops on removal from the ultraviolet light or heat and is therefore controlled by the length of exposure.

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