The viscoelastic properties of filled elastomers (uncured styrene–butadiene rubber filled with carbon black) were investigated with two shear rheometers specially designed for the characterization of complex polymer systems. A torsional strain‐controlled rheometer [i.e., a rubber process analyzer (RPA)] was used in dynamic and relaxation modes for measuring the storage and loss moduli and the relaxation modulus. A stress‐controlled sliding cylinder rheometer (SCR) was operated for the measurement of the creep compliance. Both devices could be operated on a large scale of imposed strains or stresses ranging from the linear viscoelastic regime to the nonlinear viscoelastic regime, and they were complementary in supporting the original viscoelastic behavior of filled elastomers for a wide experimental time range. Moreover, when the measuring ranges of the two apparatus overlapped, a cross‐check of the material functions obtained with the RPA or SCR could be successfully carried out. This validation of the data was performed not only in the linear domain of viscoelasticity, with the classical approach of a generalized Maxwell model, but also in the nonlinear domain, with a viscoelastic integral model of type K‐BKZ. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 87: 31–41, 2003

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PET imaging may differentiate responding and nonresponding tumors early in the course of therapy. By avoiding ineffective and potentially harmful treatment, this may markedly facilitate the use of preoperative therapy, especially in patients with potentially resectable tumors.

ObjectiveTo analyze the changing pattern in tumor type and postoperative deaths at a national referral center for esophageal cancer in the Western world and to assess prognostic factors for long-term survival after resection. Summary Background DataDuring the past two decades, the epidemiology and treatment strategies of esophageal cancer have changed markedly in the Western world. The influence of these factors on postoperative deaths and long-term prognosis has not been adequately evaluated. MethodsBetween 1982 and 2000, 1,059 patients with primary esophageal squamous cell cancer or adenocarcinoma had resection with curative intention at a single center. Patient and tumor characteristics and details of the surgical procedure and outcome were documented during this period. Follow-up was available for 95.8% of the patients. Changing patterns in tumor type and postoperative deaths were analyzed. Prognostic factors for longterm survival were assessed by multivariate analysis. ResultsThe prevalence of adenocarcinoma in patients with resected esophageal cancer increased markedly during the study period. The postoperative death rate decreased from about 10% before 1990 to less than 2% since 1994, coinciding with the introduction of a procedure-specific composite risk score and exclusion of high-risk patients from surgical resection. In addition to the well-established prognostic parameters, tumor cell type "adenocarcinoma" was identified as a favorable independent predictor of long-term survival after resection. The independent prognostic effect of tumor cell type persisted in the subgroups of patients with primary resection and patients with primary resection and R0 category.