Pathologic Evaluation of Routine Nasopharynx Punch Biopsy in the Adult Population: Is It Really Necessary?

Objectives To retrospectively evaluate the patients who underwent nasopharyngeal biopsy with imaging and biopsy results, who have or don’t have symptoms for nasopharyngeal pathology and to determine the ratio of the nasopharyngeal cancer cases and other pathologic conditions. Methods In this retrospective study, 983 patients who underwent endoscopic nasopharyngeal biopsy for symptomatic nasopharyngeal lesions were included. All pathological results, benign or malign was recorded and classified due to the patients’ presenting symptoms such as symptomatic for nasopharyngeal pathology or asymptomatic. Computed tomography (CT) or magnetic resonance imaging (MRI) reports were also recorded separately as group A for malignancy or group B for not malignancy. Results Forty-five (4.6%) of 983 biopsies were malignant. In this group, there is no statistically significant difference between symptomatic and asymptomatic group. For malignant pathologies, the sensitivity of MRI was found 88.2% and CT was 61.5%. Conclusion For early diagnosis of nasopharyngeal cancer, all patients admitted to Ear, Nose and Throat (ENT) referral clinics should be examined endoscopically irrespective of their complaints and suspicious cases should be investigated by imaging especially by MRI. If MRI report clearly indicates Thornwaldt cyst or reactive lymphoid hyperplasia and this result is compatible with endoscopic findings, biopsy may not be necessary. Apart from these cases, all suspected lesions should be biopsied

ANALYSIS OF ORTHOTROPIC PLATE STRUCTURES BY THE DIRECT-DYNAMIC STIFFNESS METHOD

WOS: A1995RV13600006

Free vibration solution for clamped orthotropic plates using the Kantorovich method

WOS: A1996VH81100009

Analysis of energy flow in thick plate structures

WOS: A1997WD04500017At sufficiently high frequencies: where the structural wavelength is much smaller than the thickness of the structure, the rotational inertia and transverse shear effects become increasingly important. In this study the direct-dynamic stiffness method is extended to include shear deformation and rotary inertia. The present method and the statistical energy analysis (SEA) approach are used to investigate the effects of shear distortion and rotary inertia on the flexural energy transmission of a representative stiffened plate structure. It is seen that energy flow decreases significantly when compared with the transmitted energy calculated using the classical thin plate theory. Copyright (C) 1996 Elsevier Science Ltd

High frequency vibration analysis of plate structures

Noise and vibration are important design issues for many types of vehicles such as ships, cars, and aeroplanes. Structure borne sound, which may be of relatively high frequency, usually emanates from an engine or some other type of localised source and propagates through the vehicle. Excessive vibration levels, and thus structural damage, may occur while structural acoustic interactions may lead to unacceptable interior noise. In the analysis of energy transmission between plate structures, it is common practice to consider only bending modes (or waves) of the structure. However if the concern is with high frequency vibration analysis, then due allowance may need to be made for the presence of inplane shear and longitudinal modes. Due to the infeasibility of the industry standard technique, the Finite Element Method, at high frequencies, almost all of the studies that have investigated the importance of in-plane energy transmission have used Statistical Energy Analysis (SEA). In this study an existing dynamic stiffness method is extended to include in-plane effects, and used as a benchmark against which SEA is assessed. Additionally the Wave Intensity Analysis (WIA) technique, which is an improved form of SEA, is extended to in-plane vibrations, and used to identify some of the reasons for the poor performance of SEA in certain applications. All three methods are applied to a wide range of plate structures within the frequency range of 600 Hz to 20 kHz. While the response levels as predicted by the WIA are generally quite close to exact results, it has been found that although all of the requirements which are usually postulated for the successful application of SEA are fulfilled, SEA severely underpredicts the energy transmission in large structures because of the diffuse wave field assumption. It is also shown that the exclusion of in-plane modes may lead to sizeable errors in energy predictions unless the structure is very simple

An assessment of the effects of in-plane vibrations on the energy flow between coupled plates

WOS: A1996UF42000003The majority of the studies of energy transmission in plate-type structures are based on the assumption that the main component of the energy transfer is due to flexural waves, and the contribution of in-plane waves may be neglected. In this study a systematic assessment of the effects and importance of in-plane vibrations has been made by using the dynamic stiffness technique which yields ''exact'' results for a certain class of structures. The method is also used as a ''bench-mark'' to assess the predictions of the statistical energy analysis (S.E.A.) approach and the wave intensity analysis (W.I.A.) approach. It is shown that the exclusion of in-plane modes may lead to sizeable errors in energy predictions unless the structure is very simple. (C) 1996 Academic Press Limite

Natural frequencies of cross-ply laminated singly curved panels

WOS: A1996TZ84300008