[en] AIMS: This paper reports the findings of facial nodal metastasis in nasopharyngeal carcinoma (NPC). MATERIALS AND METHODS: The film records of 1916 patients with histologically confirmed NPC seen over a 5-year period were reviewed. RESULTS: Eight facial nodes were demonstrated in three (0.2%) patients. There were three buccinator, two malar, two infraorbital and one mandibular nodes. CONCLUSION: Facial nodal metastasis in NPC is unusual, but may be seen at presentation or during recurrence. Chong, V.F.H., Fan, Y.-F. (2000)

[en] Permeative infiltration of the meninges appears to be a distinct form of recurrent nasopharyngeal carcinoma (NPC). The present report of eight patients with recurrent NPC illustrates meningeal infiltration following basal foramina extension. Seven of the eight patients (88%) showed jugular foramen involvement. Three patients had concomitant infiltration of the foramen magnum. There was one patient showing spread through the foramen lacerum. Only four (50%) of these patients had clinically detectable tumour in the nasopharynx, while the other half showed deep submucosal recurrence with endoscopically unremarkable findings. Permeative meningeal infiltration appears to be a distinct form of NPC recurrence. It is important to recognize this phenomenon so as to optimize the treatment options. The imaging studies were reviewed and the following features were recorded: local nasopharyngeal recurrence, the manner of intracranial spread and site of meningeal infiltration. Four patients had only MRI, two had only CT and two patients had both CT and MRI. The presence or absence of intracranial tumour before treatment was also recorded. Two observers reviewed the images and results were arrived at by consensus. Copyright (1999) Blackwell Science Pty Ltd

[en] The nasopharynx, located just below the central skull base, is a difficult area to evaluate clinically. Endoscopic examination provides useful information but cannot delineate submucosal disease. Benign lesions of the nasopharynx are relatively uncommon. They include Thornwaldt cyst, juvenile angiofibroma, haemangioma, haemangiopericytoma, Kimura's disease, branchial cleft cyst, oncocytoma, amyloidoma, and non-ossifying fibromyxoid tumours. The most common malignant lesions are carcinomas and lymphomas. Other malignant neoplasms such as adenocystic carcinomas are rarely seen. The purpose of the present pictorial review is to highlight the salient normal anatomy of the nasopharynx and the spectrum of pathological anatomy. Small or superficial lesions are best assessed endoscopically, coupled with biopsy when deemed necessary. It is demonstrated that both computerized tomography and MRI play a central role in the evaluation of lesions involving deeper structures of the nasopharynx, especially when skull base involvement or intracranial extension is suspected. Copyright (1999) Blackwell Science Pty Ltd

[en] Negative impedance converters (NICs) are used to create impedance loads that can effectively cancel the inductive properties of magnetic dipoles, resulting in active metamaterials with increased bandwidth and reduced loss for μ-near-zero (MNZ) and negative-Re(μ) (MNG) media. We demonstrate techniques for analyzing the stability and characterizing the magnetic properties of effective media loaded with NICs. Specifically, we apply the Nyquist criterion to validate the stability of sample active metamaterials. It is shown that the practical NIC-loaded metamaterial may maintain stability and reduce dispersion, albeit with reduced performance as compared to the ideal NIC load. (paper)

[en] The influence of transverse magnetic field on the liquid-solid interface stability and morphology has been investigated in directionally solidified Al-0.85wt%Cu alloy. Experimental results show that the transverse magnetic field causes the interface to be instable and the interface shape to be depressed on one side along the radius. The interface instability increases with increasing magnetic field. Increasing the solidification velocity reduced extent of interface destabilization by the magnetic field. The depression of the interface with the magnetic field is more dramatic at low solidification velocities. These phenomena are attributed to the thermoelectromagnetic convection (TEMC) on the interface and cellular scale.