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173 results on '"Lifson, S."'

6. The reaction of O(3P) with cyclohexane clusters.

Author

Rudich, Y., Hurwitz, Y., Lifson, S., and Naaman, R.

Subjects
CYCLOHEXANE, CLUSTER theory (Nuclear physics), ABSTRACT thought, HYDROCARBONS, MOLECULAR beams
Abstract

The effect of cluster formation on the reactivity of cyclohexane was investigated. When single molecules react with O(3P) the products are the OH radical and cyclohexyl radical. In contrast, we found that when small clusters react with O(3P), the OH product is suppressed; furthermore, the ‘‘liquid’’-like product, cyclohexanol, is observed, although the yield is unknown. It is proposed that blocking of the abstraction reaction occurs in the reaction when clusters are involved. In addition, an efficient insertion process can take place. These results provide a new explanation for the process in the liquid phase. [ABSTRACT FROM AUTHOR]

Published
1993
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13. A Comparison of the Temperature Dependent 1H NMR and Empirical Force Field Techniques in Determining Enantiomeric Recognition of Organic Ammonium Salts by Chiral Di- and Tetraalkyl-Substituted Pyridino-18-Crown-6 Ligands.

Author

BRIGHAM YOUNG UNIV PROVO UT DEPT OF CHEMISTRY, Bradshaw, J. S., Zhu, C. Y., Lifson, S., Izatt, R. M., BRIGHAM YOUNG UNIV PROVO UT DEPT OF CHEMISTRY, Bradshaw, J. S., Zhu, C. Y., Lifson, S., and Izatt, R. M.

Abstract

Complexation of the (R)- and (S)- forms of alpha-(1-naphthyl) ethylammonium perchlorate by chiral pyridino-18-crown-6 ligands 1-6 has been studied by the temperature dependent 1H NMR technique. At low temperatures, the peaks in the H NMR spectra of the complexes attributable to the hydrogen atoms on the CH2 groups attached to the pyridine rings (centered at about sigma 4.5), or the methyl hydrogens in the cases of 5 and 6, separated into two peaks of equal intensities. The low temperature peak separations were 40-140 Hz. At high temperatures, the appearance of a single peak is caused by a fast intermolecular or intramolecular face to face guest exchange. The kinetic parameters for the dissociation of these complexes were calculated reported.

Published
1990

24. General discussion.

Author

Klevens, H. B., Dervichian, D. G., Overbeek, J. Th. G., Lawrence, A. S. C., Pethica, B. A., Winsor, P. A., Booij, H. L., Phillips, J. N., Few, A. V., Sumner, C. G., Blokker, P. C., Durham, K., Camp, M., Emerson, W. W., Stainsby, G., Johnson, P., Ellenbogen, E., Brand, B. P., Lifson, S., and Težak, B.

Published
1954
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27. Energy functions for peptides and proteins. II. Amide hydrogen bond and calculation of amide crystal properties

Author

Lifson S and Hagler At

Subjects
Hot Temperature, Chemical Phenomena, Low-barrier hydrogen bond, Molecular Conformation, Biochemistry, Catalysis, Structure-Activity Relationship, chemistry.chemical_compound, Colloid and Surface Chemistry, Computational chemistry, Amide, Organic chemistry, Crystal properties, Nuclear Physics, Hydrogen bond, Bond strength, Chemistry, Bond, Proteins, General Chemistry, Amides, Bond order, Amide hydrogen, Energy Transfer, Peptides, Mathematics, Hydrogen
Published
1974
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28. Molecular Weight Dependence of the Optical Rotation of Poly((R)-1-deuterio-n-hexyl isocyanate) in Dilute Solution

Author

Okamoto, N., Mukaida, F., Gu, H., Nakamura, Y., Sato, T., Teramoto, A., Green, M. M., Andreola, C., Peterson, N. C., and Lifson, S.

Abstract

Poly((R)-1-deuterio-n-hexyl isocyanate) (αPdHIC) in dilute solution is characterized by an extraordinarily large specific optical rotation [α]. Detailed [α] data were obtained for a number of nearly monodisperse αPdHIC samples in different solvents over a wide range of temperature. The results were similar to those for poly((R)-2-deuterio-n-hexyl isocyanate) (βPdHIC) reported in a previous publication (Gu, H., et al. Macromolecules 1995, 28, 1016). The molecular weight dependence of [α] was remarkable over a wide range and consistently analyzed by the statistical mechanical theory of Lifson et al. (Lifson, S., et al. J. Am. Chem. Soc. 1989, 111, 8850) for a polyisocyanate chain consisting of an alternating sequence of right-handed and left-handed helices intervened by helix reversals. It was shown that the large [α] arises from the helical conformation, where the left-handed helix exists in some excess over the right-handed one due to a small free energy favoring the former helix (2ΔGh). This energy accumulates to a significant amount on a given chain assisted by a very small helix reversal probability (ν). This confirmed a similar conclusion on βPdHIC reported in the previous paper. It was found that ν is almost the same for the two polyisocyanates but the magnitude of 2ΔGh for αPdHIC, though smaller than a few calories per mole, is about twice as large as that for βPdHIC, exhibiting a remarkable hydrogen−deuterium isotope effect on chain conformation.

Published
1996

30. On the Statistical Mechanical Theories of Helix‐Coil Transition in Polypeptides, and the Structure and Structural Stability of Proteins

Author

Lifson, S. and Lotan, N.

Abstract

The theoretical and experimental study of the helix‐coil transition of synthetic polypeptides has significantly deepened our understanding of the phenomena of nucleation and cooperativity in the equilibrium transition between the native and the denatured states of proteins. Proteins differ, however, from synthetic copolymers by being neither regular nor random, their sequence having been determined by natural selection. Therefore, the quantitative results of the theoretical analysis of synthetic polypeptides should not be indiscriminately transferred to the study of proteins. However, these results provide important information for a rational analysis of the conformation and conformational stability of proteins.

Published
1974
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33. Proposed Report on Educational Qualifications of Directors of Public Health Departments. Committee on Professional Education

Author

Burney, Leroy E., Atwater, Reginald M., Blackerby, Philip E., Bosch, Harbert M., Defries, Robert D., Hardy, Albert V., Lifson, S. S., Mickey, Janice E., Roberts, Dean W., Smiley, Dean F., Van Volkenburgh, V. A., Webster, Robert G., Burgdorf, Alfred L., Crabtree, James A., Golley, Paul M., Kinde, M. R., Mattison, Berwyn F., Mott, Frederick D., Shanholtz, Mack I., Chope, Harold D., Eller, C. Howe, Gaus, John M., Hall, Frank M., Leavell, Hugh R., Lesser, Arthur, Molner, Joseph G., Mustard, Harry S., Osborne, Frank J., Porterfield, John D., Riley, Robert H., Sondag, Robert F., Willard, William R., Burney, Leroy E., Atwater, Reginald M., Blackerby, Philip E., Bosch, Harbert M., Defries, Robert D., Hardy, Albert V., Lifson, S. S., Mickey, Janice E., Roberts, Dean W., Smiley, Dean F., Van Volkenburgh, V. A., Webster, Robert G., Burgdorf, Alfred L., Crabtree, James A., Golley, Paul M., Kinde, M. R., Mattison, Berwyn F., Mott, Frederick D., Shanholtz, Mack I., Chope, Harold D., Eller, C. Howe, Gaus, John M., Hall, Frank M., Leavell, Hugh R., Lesser, Arthur, Molner, Joseph G., Mustard, Harry S., Osborne, Frank J., Porterfield, John D., Riley, Robert H., Sondag, Robert F., and Willard, William R.

Published
1955

34. Proposed Report on Field Training of Public Health Personnel. Committee on Professional Education

Author

Burney, Leroy E., Atwater, Reginald M., Blackerby, Philip E., Bosch, Herbert M., Defries, Robert D., Hardy, Albert V., Lifson, S. S., Mallery, Otto T., McGavran, Edward G., Mickey, Janice E., Roberts, Dean W., Smiley, Dean F., Webster, Robert G., Gibson, William C., Kinde, M. R., Lovell, S. Elizabeth, McIver, Pearl, Malcolm, James C., Robins, Hugh B., Smillie, Wilson G., Burney, Leroy E., Atwater, Reginald M., Blackerby, Philip E., Bosch, Herbert M., Defries, Robert D., Hardy, Albert V., Lifson, S. S., Mallery, Otto T., McGavran, Edward G., Mickey, Janice E., Roberts, Dean W., Smiley, Dean F., Webster, Robert G., Gibson, William C., Kinde, M. R., Lovell, S. Elizabeth, McIver, Pearl, Malcolm, James C., Robins, Hugh B., and Smillie, Wilson G.

Published
1955

35. Proposed Report on Educational Qualifications of Public Health Dental Hygienists. Committee on Professional Education

Author

Blackerby, Philip E., Atwater, Reginald M., Bosch, Herbert M., Defries, Robert D., Felix, R. H., Hardy, Albert V., James, George, Lifson, S. S., Mallery, Otto T., McGavran, Edward G., Mickey, Janice E., Roberts, Dean W., Webster, Robert G., Galagan, Donald J., Ast, David B., Ayers, Polly, Hannon, Evelyn R., Jeffreys, Margaret H., Sebelius, Carl, Swanson, Margaret, Warner, Elizabeth M., Blackerby, Philip E., Atwater, Reginald M., Bosch, Herbert M., Defries, Robert D., Felix, R. H., Hardy, Albert V., James, George, Lifson, S. S., Mallery, Otto T., McGavran, Edward G., Mickey, Janice E., Roberts, Dean W., Webster, Robert G., Galagan, Donald J., Ast, David B., Ayers, Polly, Hannon, Evelyn R., Jeffreys, Margaret H., Sebelius, Carl, Swanson, Margaret, and Warner, Elizabeth M.

Published
1956

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