Demonstration of a semiconductor external cavity laser using a UVwritten grating in a planar silica waveguide

The authors report the first demonstration of a semiconductor external cavity waveguide laser, modulated at 2.5 Gbit/s over 100 km of standard optical fibre using a UV written grating in a planar silica waveguide as the feedback element     

Oculomotor paralysis. The perspective of a neuro-ophthalmology consultation

Ocular paresis is a usual diagnosis in neuro-ophthalmologic consultation, and its aetiology is indeed a challenge. The authors studied 3400 records concerning this consultation, between 1982 and the third quarter of 1993. During this period 221 cases with ocular paresis were selected. During this retrospective study we point out the following items: the cranial nerve affected; the neuro-ophthalmologic semiology; the aetiology and clinical evolution, according to the age groups. From 221 cases selected, 111 were paresis from the VIth pair (50.2%), 88 from the IIIrd pair (39.8%), 14 multiple paresis (6.4%) and 8 paresis from the IVth pair (3.6%). The most frequent complaint was diplopia (> 90%). As far as the aetiological diagnosis is concerned, this was easier to establish in patients > 50 years of age. In this age group the most usual aetiology was vascular and traumatic pathologies. In younger patients the most frequent pathologies were traumatic and tumoral. The prognostic was better in the vascular group, the paresis recovery being > 50% in all other pathologies, except the tumoral one.     

Roxatidine versus ranitidine in the treatment of duodenal ulcer: a randomized, double blind, controlled, multicenter study in Thailand

BACKGROUND: Roxatidine acetate is a novel H2-receptor antagonist and several studies have shown that it is effective in healing duodenal ulcers. We evaluated the efficacy of roxatidine in a non-western society with particular different features and its healing of duodenal ulcers was compared in Thailand with that of ranitidine. METHOD: The design was controlled, randomized, double-blind, and multicenter. The study recruited a total of 215 patients who were endoscoped at the start of the trial and then randomized to receive a single capsule of roxatidine acetate, 150 mg, or an identical capsule containing ranitidine, 300 mg, both to be taken at night. Patients were evaluated at 1, 2, and 4 weeks, including endoscopy at the last session, as well as at 6 weeks with repeat endoscopy if the ulcer had not healed. RESULT: Both drugs relieved pain rapidly, usually within a week, and at repeat endoscopy at 4 weeks most ulcers (78%) were healed, 77.0 and 79.5 per cent in ranitidine and roxatidine, and in those patients in whom healing was not completed the healing rate had risen appreciably to 89.8 and 93.8 per cent respectively at 6 weeks. Small ulcers tended to heal quicker than larger ones, but smoking and alcohol intake had no negative effects on the results. CONCLUSION: The study was valid proof that roxatidine, in a single evening dose of 150 mg, was found to be both safe and effective in the rapid healing of duodenal ulcers when compared with 300 mg ranitidine.     

Three-dimensional anatomical model-based segmentation of MR brainimages through principal axes registration

Model-based segmentation and analysis of brain images depends on anatomical knowledge which may be derived from conventional atlases. Classical anatomical atlases are based on the rigid spatial distribution provided by a single cadaver. Their use to segment internal anatomical brain structures in a high-resolution MR brain image does not provide any knowledge about the subject variability, and therefore they are not very efficient in analysis. The authors present a method to develop three-dimensional computerized composite models of brain structures to build a computerized anatomical atlas. The composite models are developed using the real MR brain images of human subjects which are registered through the principal axes transformation. The composite models provide probabilistic spatial distributions, which represent the variability of brain structures and can be easily updated for additional subjects. The authors demonstrate the use of such a composite model of ventricular structure to help segmentation of the ventricles and cerebrospinal fluid of MR brain images. Here, a composite model of ventricles using a set of 22 human subjects is developed and used in a model-based segmentation of ventricles, sulci, and white matter lesions. To illustrate the clinical usefulness, automatic volumetric measurements on ventricular size and cortical atrophy for an additional eight alcoholics and 10 normal subjects were made. The volumetric quantitative results indicated regional brain atrophy in chronic alcoholics     

Mine operating accurate stability control with optical fibersensing and Bragg grating technology: the European BRITE/EURAM STABILOSproject

Recent developments of stability control in mines, essentially based on Ge-doped fiber Bragg gratings (FBG) are reported including results about the different aspects of the system: accurate characterizations of FBG, sensor network topology and multiplexing method, user interface design and sensor packaging