Showing papers by "University of Duisburg-Essen published in 1980"

A Solution of the Earthed Fin Line with Finite Metallization Thickness

Abstract: A method is presented which solves the eigenvalue problem of an earthed fin line considering finite metallization thickness as well as a longitudinal slit in the metal waveguide-mount. Numerical and experimental results are given for the unilateral fin line.

Sequentiell alternierende Chemotherapie nicht-seminomatöser Hodentumoren mit Velbe/Bleomycin und Adriamycin/Cisplatin - I. Ergebnisse einer randomisierten Studie bei 71 Patienten mit pulmonaler Metastasierung (Stadium IV)

Abstract: 74 patients with disseminated non-seminomatous testicular cancer were randomly entered on a prospective sequential combination chemotherapy regimen with mandatory crossover, consisting of either vinblastine/bleomycin or adriamycin/cis-dichlorodiammineplatinum (II) (DDP) as initial therapy. Independent of the randomization the overall remission rate in 71 evaluable patients was 89% including 54% complete remissions. 35% of the patients remained disease-free at 2+ to 28+ months with a median of 12 months. By additional surgical removal of residual pulmonary metastases in two patients the complete remission rate was increased to 40/71 (56%), and the number of patients with no evidence of disease to 27/71 (38%). According to the life-table method the two-years survival rates were 63% for complete responders and 29% for all other patients, which was significantly lower. 53 patients (75%) were alive at 3 to 28 months with a median of 9 months. Additional advanced abdominal disease, initially elevated beta-HCG and LDH and extension of pulmonary disease were of significant negative influence on the prognosis. The evaluation of single chemotherapy courses revealed equal efficacy of both combinations. However, response to adriamycin/DDP occurred in 46% of the courses, when vinblastine/bleomycin had failed, while response to vinblastine/bleomycin occurred only in 21% of the courses when adriamycin/DDP had failed. Thus different patterns of cross-resistance between these alternative regimens may exist.

Sequential combination chemotherapy with vinblastine-bleomycin and doxorubicin-cis-dichlorodiammineplatinum(II) in disseminated nonseminomatous testicular cancer.

Abstract: Forty-two patients with disseminated nonseminomatous testicular cancer were randomly entered to receive a two-armed chemotherapy regimen with mandatory crossover, consisting of either vinblastine-bleomycin or doxorubicin-cis-dichlorodiammineplatinum(II) (DDP) as initial therapy. Forty of these patients received at least four courses and were considered evaluable. Twenty-five of these patients received vinblastine-bleomycin and 15 received doxorubicin-DDP as initial treatment. The overall remission rate was 88%, with a complete remission rate of 68%. Thirty-two patients remain alive and 20 (50%) remain disease-free at 3+ to 18+ months, with a median duration of complete remissions of 9+ months. The response rate was not affected by prior chemotherapy or radiotherapy. Either treatment arm proved equally effective. However, response with doxorubicin-DDP therapy occurred in nine of 19 treatment courses when vinblastine-bleomycin therapy had failed, while response with vinblastine-bleomycin therapy occurred in only two of 11 treatment courses when doxorubicin-DDP therapy had failed. Thus, different patterns of cross-resistance between these alternative regimens may exist.

Eine Meßapparatur zur Untersuchung des Kriech- und Relaxationsverhaltens von Polymeren unter Torsion

Abstract: Zur experimentellen Bestimmung der Kriechfunktion J(t) und der Relaxationsfunktion G(t) unter Torsionsbelastung der Probe wurde eine Mesapparatur entwickelt. Das mechanisch-elektrische Mesprinzip sowie eine Prozesrechnerkopplung gestatten einen weitgehend automatischen Mesbetrieb. Anderungen an den physikalischen Versuchsbedingungen konnen rein Software-seitig durchgefuhrt werden. Das entsprechende Auswerteprogramm liefert neben numerischen Werten eine Zeichnung der entsprechenden Masterkurven, die mit Hilfe der WLF-Gleichung konstruiert werden. Messungen an kommerziellem PMMA zeigen einen Mesz bereich furJ(t) von 10−9 bis 10−5 m2/N und fur G(t) von 10° bis N 105 N/m2 ; das zugangliche Temperaturintervall liegt zwischen −180 °C und 200 °C. Damit ist der fur die meisten Polymere erforderliche Bereich erfast.

Resümee und Perspektiven

Abstract: Die Ergebnisse der Befragung deuten an, das die kommunikativen Beziehungen zwischen den Lehramtsanwartern und den verschiedenen Ausbildern zwar im Einzel fall sich nicht immer storungsfrei entwickeln (das Ausmas und die Wirkung solcher Turbulenzen konnen aufgrund der Wahl des methodischen Instruments dieser Untersuchung nicht prazise bestimmt werden), i.d.R. allen Betroffenen aber weit mehr positive Erfahrungen uber den jeweils anderen vermitteln. Diese Feststellung gilt zumindest fur Lehramtsanwarter, die wenigstens ein halbes Jahr am Bezirksseminar ausgebildet worden sind.