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In 194 healthy children of all ages, sonographic measurements of the liver and spleen were performed on standardized section planes and normal values established. These measurement values showed an approximately linear increase in the course of development and correlated best with the body length. For a rapid orientational evaluation of the liver size, sonographic nomograms of the individual measurements were developed. The spleen size was determined by volume calculation. On the basis of an index of liver size, which was calculated from the individual measurements, a diagram for simultaneous determination of liver and spleen size could be developed. These nomograms permit objective morphometry of size changes in the two organs.

The dipole moments of four photochromic derivatives of indolinospirobenzopyran have been studied in their spiro and their open merocyanine form, in dioxane. Determinations have been done by electrooptical absorption measurements (EOAM). To prepare either a pure spiropyran or a pure merocyanine form solution, the experimental setup had to be modified by addition of a second light beam. In this way thermal equilibration between the spiropyran and the merocyanine form and switching from one form to the other induced by the measuring light beam could be avoided. The ground-state dipole moment of the spiro form amounts to (10-15) × 10 -30 C m and increases strongly to about 60 × 10 -30 C m with the excitation to the first excited singlet state. The ground-state dipole moment of the merocyanine form is much larger and amounts to (50-60) × 10 -30 C m. In contrast to the spiro form it decreases to about 40 × 10 -30 C m, when exciting to the first excited singlet state of the merocyanine form. † Part of the special issue "Noboru Mataga Festschrift".

Picosecond time-resolved absorption spectra of 4-(9-anthryl)-A',/Y-dimethylaniline (ADMA) and related methyl derivatives in the excited singlet state have been measured in various solvents. Analysis of the solvent dependence of the transient absorption spectra indicates the existence of "multiple excited states" of ADMA with different degrees of charge transfer. Picosecond time-resolved transient absorption spectra in a viscous polar solvent, butanol, show a gradual change of the electronic structure of excited ADMA in the course of the reorientational relaxation of solvent molecules. The mechanisms of the solvent-induced change of the electronic structure of excited ADMA are discussed in relation to the TICT (twisted intramolecular charge transfer) model.