Impact of hyperthermic regional perfusion therapy on cell metabolism of malignant melanoma monitored by 31P MR spectroscopy

For the first time, the influence of hyperthermic regional perfusion therapy on tumor cell metabolism has been monitored by means of 31P MR spectroscopy. Shortly after treatment, a complete depletion of high energy phosphates, a significant increase of inorganic phosphate, phosphomono- and phosphodiester resonances and a decrease of pH have been observed. Healthy muscle tissue showed only minor effects caused by this aggressive therapy. The time course of the transient variation of phosphate metabolite concentrations is explained in the framework of a simple pathophysiological model. The results demonstrate that the imediate effect of chemotherapy on tumor tissue can be detected by 31P MRS before any clinical signs of tumor response are visible.     

On the Majorana equations and the rest mass of neutrinos

As is well known, the law of parity conservation does not hold in weak interactions. This type of asymmetry created a number of theoretical problems which were solved, first of all, by a new understanding of the features of neutrinos and their role in weak interactions. These solutions were based, however, essentially on the handedness (chirality) of neutrinos which is closely related to their vanishing rest mass. The thesis of neutrinos with nonvanishing rest mass, newly considered in the literature, therefore requires a rediscussion of the early arguments concerning the relation between the neutrino theory and some weak interaction essentials. When one does this, as in the present paper, it is noted that neutrinos with rest mass lead to some difficulties, in particular to a violation of T invariance.     

Hall effect of noncrystalline Zr−Cu films

Quench condensed Zr _x Cu_1–x films offer a wide concentration range (0.1x0.9) for measurements of the Hall coefficientR _H of amorphous Zr–Cu alloys.R _H changes sign as a function of composition, from negative to positive, as the Zr concentration is increased. The sign change is observed in a narrow concentration range at aboutx=0.22, without any peculiarity of the conductivity at this crossover concentration. The Hall coefficient of the unannealed Zr-rich films is nearly independent of temperature. However, both, the values ofR _H and of the temperature dependence ofR _H change with a heat treatment well below the crystallization temperature. This is most obvious for the films with a composition close to the cross-over concentration.Dedicated to B. Mühlschlegel on the occasion of his 60th birthday     

Study of the level structure of239U using the thermal neutron capture reaction

For the investigation of vibrational states in odd A nuclei we have studied the level structure of²³⁹U by the²³⁸U (n _thermal,γ) reaction. Various complementary measurement techniques as curved-crystal-, anti-Compton-,γ-γ coincidence- and conversion electron spectroscopy have been applied. The resulting data have been used to establish the deexcitation scheme of²³⁹U up to ～1.3 MeV and to make spin assignments. Most of the levels are interpreted in terms of the Nilsson model. The data also indicate the presence of the Nilsson states ¦501?¦ and ¦750¦. Three members of theΒ-vibrational band built on the ¦631?¦ state and one member of theΒ-vibration built on the ¦622↑¦ ground state have been identified through transitions with strongE0 admixtures. The octupole vibrational state built on the ¦631?¦ band is proposed at 815 keV.     

Diffusive motion of iron microcrystals studied by Mössbauer spectroscopy

A new model is presented which explains well the dramatic decrease of the Mössbauer line intensities with raising temperatures for freely dispersed iron microscrystals. In contrast to other theories which consider mainly vibration to be responsible we discuss here the decrease in terms of large amplitude diffusive rotational or translational jumps of the particles. Such diffusive jumps lead — in agreement with the observation — to a strong reduction of the Mössbauer-intensity without broadening the line width in a noticeable way. The typical potential well for a diffusing particle in an equilibrium position is derived quantitatively to be 13 meV. The model might be important also for a new understanding of the dynamics of catalytic clusters either in contact with each other or with larger solid surfaces.Part of this work was supported by the DFG Sonderforschungsbereich 306, Konstanz     

Breathing muscle activity and subglottal pressure dynamics in singing and speech

Previous studies have indicated that the diaphragm may contribute to the accomplishment of the quick and precise subglottal pressure changes required during singing. The present investigation compares data collected from simultaneously recorded electromyograms from breathing muscles and transdiaphragmatic pressure during singing as well as during nonsense and emphatic speech.     

Study of the reaction238U (α, α′f) atE α=480 MeV

The excitation function of the fission probability P _E E _x) for²³⁸U has been measured in the reaction²³⁸U(α, α′ f) at 480 MeV bombarding energy. The reaction mechanism of this reaction is discussed for excitation energies belowB _nf , the threshold for second chance fission, and aboveB _nf up toE _x =37 MeV. In comparing with results from fission induced by photons and by particle transfer reactions the (α, α′f) reaction gives too low values for the fission probabilityP _f at excitation energies well aboveB _nE . The role of the quasi-elastic knock-out process in this reaction is discussed.