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591.
Cell survival, synergistic interaction, liquid-holding recovery (LHR) kinetics and inactivation forms after the simultaneous treatment with UV light (254 nm) and various high temperatures were studied in diploid yeast cells Saccharomyces cerevisiae. The synergistic interaction was observed within a certain temperature range in which there was a temperature that maximizes the synergistic effect. The LHR study revealed that both the extent and the rate of recovery greatly decreased with the increase in exposure temperature. A quantitative approach describing the LHR process as a decrease in the effective radiation dose was used to estimate the probability of recovery per unit time and the irreversible component of damage. Using the experimental data obtained and the mathematical model described, it was shown that the irreversible component, i.e. the fraction of cells incapable of recovery, increased with the exposure temperature, whereas the recovery constant, i.e. the probability of recovery per unit time, was independent of the exposure temperature. The increase in the irreversible component was accompanied by an increase in cell death without postirradiation division. It is concluded based on this that the synergistic interaction of UV light radiation and hyperthermia in yeast cells is not related to the impairment of the recovery process itself and that it may be attributed to an increased yield of the irreversible damage. 相似文献
592.
The dual variety X* for a smooth n-dimensional variety X of the projective space PN is the set of tangent hyperplanes to X. In the general case, the variety X* is a hypersurface in the dual space (PN)*. If dimX*<N–1, then the variety X is called dually degenerate.
The authors refine these definitions for a variety XPN with a degenerate Gauss map of rankr. For such a variety, in the general case, the dimension of its dual variety X* is N–l–1, where l=n–r, and X is dually degenerate if dimX*<N–l–1.
In 1979 Griffiths and Harris proved that a smooth variety XPN is dually degenerate if and only if all its second fundamental forms are singular. The authors generalize this theorem for a variety XPN with a degenerate Gauss map of rankr.
Mathematics Subject Classification (2000) 53A20. 相似文献
593.
An n-dimensional submanifold X of a projective space P
N
(C) is called tangentially degenerate if the rank of its Gauss mapping gamma;; X G(n, N) satisfies 0 < rank < n. The authors systematically study the geometry of tangentially degenerate submanifolds of a projective space P
N
(C). By means of the focal images, three basic types of submanifolds are discovered: cones, tangentially degenerate hypersurfaces, and torsal submanifolds. Moreover, for tangentially degenerate submanifolds, a structural theorem is proven. By this theorem, tangentially degenerate submanifolds that do not belong to one of the basic types are foliated into submanifolds of basic types. In the proof the authors introduce irreducible, reducible, and completely reducible tangentially degenerate submanifolds. It is found that cones and tangentially degenerate hypersurfaces are irreducible, and torsal submanifolds are completely reducible while all other tangentially degenerate submanifolds not belonging to basic types are reducible. 相似文献
594.
595.
Assuming the validity of the law of mass action for particles, the relationships for the calculation of the activities of chemical individuals from the concentration of particles in a homogeneous system, are derived using the transformation of baricentric coordinates. These relationships can be applied to general disorder models, and they can serve for the selection of the correct and optimum methods for the comparison between disorder models and experimental data. Possible methods of application to binary and ternary systems are discussed. 相似文献
596.
The study of the Dirac system and second-order elliptic equations with complex-valued coefficients on the plane naturally leads to bicomplex Vekua-type equations (Campos et al. in Adv Appl Clifford Algebras, 2012; Castañeda et al. in J Phys A Math Gen 38:9207–9219, 2005; Kravchenko in J Phys A Math Gen 39:12407–12425, 2006). To the difference of complex pseudoanalytic (or generalized analytic) functions (Bers in Theory of pseudo-analytic functions. New York University, New York, 1952; Vekua in Generalized analytic functions. Nauka, Moscow (in Russian); English translation Oxford, 1962. Pergamon Press, Oxford, 1959) the theory of bicomplex pseudoanalytic functions has not been developed. Such basic facts as, e.g., the similarity principle or the Liouville theorem in general are no longer available due to the presence of zero divisors in the algebra of bicomplex numbers. In the present work we develop a theory of bicomplex pseudoanalytic formal powers analogous to the developed by Bers (Theory of pseudo-analytic functions. New York University, 1952) and especially that of negative formal powers. Combining the approaches of Bers and Vekua with some additional ideas we obtain the Cauchy integral formula in the bicomplex setting. In the classical complex situation this formula was obtained under the assumption that the involved Cauchy kernel is global, a very restrictive condition taking into account possible practical applications, especially when the equation itself is not defined on the whole plane. We show that the Cauchy integral formula remains valid with the Cauchy kernel from a wider class called here the reproducing Cauchy kernels. We give a complete characterization of this class. To our best knowledge these results are new even for complex Vekua equations. We establish that reproducing Cauchy kernels can be used to obtain a full set of negative formal powers for the corresponding bicomplex Vekua equation and present an algorithm which allows one their construction. Bicomplex Vekua equations of a special form called main Vekua equations are closely related to stationary Schrödinger equations with complex-valued potentials. We use this relation to establish useful connections between the reproducing Cauchy kernels and the fundamental solutions for the Schrödinger operators which allow one to construct the Cauchy kernel when the fundamental solution is known and vice versa. Moreover, using these results we construct the fundamental solutions for the Darboux transformed Schrödinger operators. 相似文献
597.
We prove that the generalized Swift–Hohenberg equation with nonlinear right-hand side, a natural generalization of the Swift–Hohenberg equation arising in physics, chemistry and biology and describing inter alia pattern formation, has no nontrivial local conservation laws.
相似文献598.
We present the quantum mechanical expressions for the angular momentum distribution of the photofragments produced in slow predissociation. The paper is based on our recent theoretical treatment [J. Chem. Phys. 123, 034307 (2005)] of the recoil angle dependence of the photofragment multipole moments which explicitly treat the role of molecular axis rotation on the electronic angular momentum polarization of the fragments. The electronic wave function of the molecule was used in the adiabatic body frame representation. The rigorous expressions for the fragment state multipoles which have been explicitly derived from the scattering wave function formalism have been used for the case of slow predissociation where a molecule lives in the excited quasibound state much longer than a rotation period. Possible radial nonadiabatic interactions were taken into consideration. The optical excitation of a single rotational branch and the broadband incoherent excitation of all possible rotational branches have been analyzed in detail. The angular momentum polarization of the photofragments has been treated in the high-J limit. The polarization of the photofragment angular momenta predicted by the theory depends on photodissociation mechanism and can in many cases be significant. 相似文献
599.
Vladislav Yu. KorotaevAlexey Yu. Barkov Pavel A. SlepukhinMikhail I. Kodess Vyacheslav Ya. Sosnovskikh 《Tetrahedron letters》2011,52(44):5764-5768
A new type of ring-ring isomerism, which consists of the reversible transformation of cyclobutane derivatives into substituted 1,2-oxazine N-oxides was found and studied by NMR spectroscopy and X-ray diffraction analysis. The starting materials were prepared by the stereoselective reaction of α-(trifluoroethylidene)nitroalkanes, which react with ethyl β-morpholino- and β-piperidinocrotonates at the more nucleophilic α-position, whereas the reaction of α-(trichloroethylidene)nitroalkanes proceeds at the β-methyl group to give the corresponding linear products. 相似文献
600.
Raúl Castillo Pérez Vladislav V. Kravchenko Rabindranath Reséndiz Vázquez 《Mathematical Methods in the Applied Sciences》2011,34(4):455-468
We propose a method for solving boundary value and eigenvalue problems for the elliptic operator D = div p grad + qin the plane using pseudoanalytic function theory and in particular pseudoanalytic formal powers. Under certain conditions on the coefficients p and q with the aid of pseudoanalytic function theory a complete system of null solutions of the operator can be constructed following a simple algorithm consisting in recursive integration. This system of solutions is used for solving boundary value and spectral problems for the operator D in bounded simply connected domains. We study theoretical and numerical aspects of the method. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献