RESUMO
In this article, extensional rheological data of various polymer solutions, to be used in Azad Trivedi viscoelastic model (AT-VEM) for predicting the viscoelastic behavior of synthetic polymer in porous media are provided. Extensional rheology measurements are performed for different polymer solutions using Capillary breakup extensional Rheometer (CaBER) to obtain the filament diameter with respect to time. Extensional rheological parameters, such as the extensional relaxation time, maximum elongational viscosity at the critical Deborah number and strain hardening index are determined from observed filament diameter with time-based on the Upper Convected Maxwell model, the finite extensible non-linear elastic model, and the power law model.
RESUMO
In Indian subcontinent, all types of nasopharyngeal masses are rare. However, Nasopharyngeal carcinoma is not uncommon in Bangladesh. It is very important to differentiate malignant from benign lesions early in the disease process. In recent years, CT is the primary diagnostic screening modality for the detection of nasopharyngeal pathology. This cross sectional study was carried out in the Department of Radiology & Imaging, BSMMU in collaboration with Department of otolaryngology of the same hospital from July 2012 to June 2014. Sensitivity of CT scan in diagnosis of nasopharyngeal carcinoma was 100%, specificity was 93.10%, positive predictive value (PPV) was 93.94%, negative predictive value (NPV) was 100% and accuracy was 96.67%. Sensitivity of CT scan in diagnosis of benign angiofibroma was 78.26 %, specificity was 89.19%, positive predictive value (PPV) was 81.82%, negative predictive value (NPV) was 86.84% and accuracy was 85% of CT scan. CT scan findings of the present study correlated well in most of the cases with the histopathological evaluations. Considering the high validity parameter it can come to a conclusion that CT scan is as highly effective as histopathology in diagnosis of nasopharyngeal mass.
