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PubMed2005

Learning from the acquired optimized pulse shapes about the isotope selective ionization of potassium dimers.

Selective optimization of the 39,39K2 and 39,41K2 isotopomers in a three-photon ionization process is presented by applying evolution strategies on shaped fs pulses in a feedback loop. The optimizations at different center wavelengths show considerably large enhancements of one isotope compared to the other and reversed. We compare the acquired optimized pulse shapes for combined phase and amplitude with pure amplitude modulation. Particularly from their spectra we are able to extract information about the optimally chosen differing ionization paths via the involved vibrational states. Furthermore, a comparison of the temporal shape of the optimized pulse forms for combined phase and amplitude with pure phase optimization is given. The presented pulse form analysis demonstrates the potential of restricted optimization to gain insight into the underlying dynamical processes. Our approach reveals how the optimization algorithm precisely addresses the vibrational wave functions both spectrally and temporally.

Journal Article↗
PubMed1965

CAT HEART MUSCLE IN VITRO. VII. THE TEMPERATURE DEPENDENCE OF STEADY STATE K EXCHANGE IN PRESENCE AND ABSENCE OF NACL.

In quiescent cat papillary muscles J(K), the rate of exchange of cellular K with K(42) in the steady state, has been measured in the presence and absence of NaCl over a wide range of temperatures. J(K) was found to be independent of the presence of external NaCl under the steady state conditions investigated. The Arrhenius plot for K exchange was linear over a range of temperatures from 2.5 to 37.5 degrees C in the absence of NaCl, and from 17.5 to 37.5 degrees C in the presence of NaCl. The corresponding apparent activation energies were, respectively, 10,200 and 8,800 calories/mole. J(K) in the absence of NaCl was not affected by 10(-5)M ouabain. These results are consistent with a passive distribution for the K of heart muscle cells. The observations suggest that a carrier-mediated forced exchange of K for Na does not occur during the steady state in mammalian heart muscle.

Animals↗