For Daniel Greenberger on His 65th Birthday

Dedication

For Daniel Greenberger on His 65th Birthday     

MRI-assisted radiation therapy planning of brain tumors--clinical experiences in 17 patients

A new and simple method for precise determination of lateral opposed treatment portals was developed and used in 17 patients. Compared to CT, MRI led to significant changes of portals in 59% (10/17) of cases. Individual shielding blocks could be precisely designed by use of our new method. MRI is the procedure of choice in local radiation therapy planning of brain tumors.     

The capability of ultrafiltration and ETV-ICP-MS for size fractionation studies of arsenic and selenium species in ground water samples with high concentrations of iron, manganese and sulfur

A simple, but highly sensitive procedure for the determination of particular and colloidally bound arsenic and selenium species in ground water samples with high concentrations of iron, manganese and sulfur is presented. Samples were first filtered through a 0.45 μm filter to separate the particulate matter from the dissolved. Aliquots of the filtered sample were submitted to ultrafiltration through membrane filters with pore diameters of 30 nm and 1 nm, respectively. Filtrates were analyzed by ETV-ICP-MS for their arsenic and selenium concentration. Received: 24 October 1997 / Revised: 17 March 1998 / Accepted: 28 March 1998     

α'β-Elimination and wittig rearrangement of the carbanion from benzyl cyclooctyl ether

Beside the Wittig rearrangement and the migration of the cyclooctyl radical to the para position, the title carbanion gives rise to an elimination in a syn process.     

Collective and two-quasiparticle states in 158Gd observed through study of radiative neutron capture in 157Gd

The level structure of ¹⁵⁸Gd has been studied using the prompt γ-rays and conversion electrons emitted following neutron capture in ¹⁵⁷Gd. The γ-ray energy and intensity measurements were made using both Ge(Li) detectors and a curved-crystal spectrometer. Conversion-electron energy and intensity measurements were made using two separate magnetic spectrometers: one to measure the primary electron spectrum and the other to measure the lower energy secondary electron spectrum. Some γ-γ coincidence measurements were also made among the secondary γ-rays. From these data, a neutron separation energy of 7937.1 ± 0.5 keV has been determined for ¹⁵⁸Gd. A level scheme containing 59 excited states with energies < 2.25 MeV, for which de-excitation modes have been identified, is proposed for ¹⁵⁸Gd. Many of these states have been grouped into rotational bands. A total of thirteen excited rotational bands with band-head energies below 2.0 MeV are contained in the level scheme. Features of the proposed level scheme include: the K^π = 0^?, 1^? and 2^? octupole-vibrational bands with band-head energies of 1263, 977 and 1793 keV, respectively; the γ-vibrational band at 1187 keV; three excited K^π = 0⁺ bands with band-head energies of 1196, 1452 and 1743 keV; several two-quasiparticle bands with band-head energies in keV (and K^π assignments) of 1380 (4⁺), 1636 (4^?), 1847 (1⁺), 1856 (1^?), 1920 (4⁺) and 1930 (1⁺). An analysis of (d, p) reaction data is presented which permits definite two-quasiparticle configuration assignments to be made to most of these latter bands. Evidence is presented which suggests strong mixing of some two-neutron and two-proton bands. A phenomenological four-band mixing analysis is made of the energy and E2 transition-probability data for the ground-state band and the three lowest-lying excited collective positive-parity bands. Good agreement with experiment is obtained. A Coriolis-mixing analysis of the octupole bands has been carried out and good agreement with the data on level energies and E1 transition probabilities to the ground-state band has been achieved. Values of Z, the ratio of the E1 transition matrix element with ΔK = 1 to that with ΔK = 0, involving the octupole bands and the first four 0⁺ bands are derived. For three of these 0⁺ bands, absolute values of these matrix elements are deduced. An interesting alternation in the sign of Z is observed for these four 0⁺ bands.     

Polymere mit dem Zentralatom eines Makrocyclus in der Hauptkette. 1. Mitt. Polykondensationsreaktionen mit Phthalocyaninsilicium-und Hemiporphyrazingermaniun-Verbindungen

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