Cookbook asymptotics for spiral and scroll waves in excitable media.

Algebraic formulas predicting the frequencies and shapes of waves in a reaction-diffusion model of excitable media are presented in the form of four recipes. The formulas themselves are based on a detailed asymptotic analysis (published elsewhere) of the model equations at leading order and first order in the asymptotic parameter. The importance of the first order contribution is stressed throughout, beginning with a discussion of the Fife limit, Fife scaling, and Fife regime.

Large-excitability asymptotics for scroll waves in three-dimensional excitable media.

Three-dimensional scroll waves are considered in a reaction-diffusion model of excitable media in the large excitability limit. Coordinates based on the scroll filament are defined and shown to provide a natural extension of the coordinates used for two-dimensional spiral waves. The leading-order free-boundary equations for interface motion in three dimensions are explicitly derived in these coordinates.

Selection of twisted scroll waves in three-dimensional excitable media.

The selection of shape and rotation frequency for scroll waves in reaction-diffusion equations modeling excitable media is investigated. For scrolls with uniform twist about straight filaments, asymptotic methods are used to derive free-boundary equations at leading and first order. Both orders are validated against full solutions of the reaction-diffusion equations.

Cathepsin D in normal and neoplastic thyroid tissues.

Background: Cathepsin D is a widely distributed lysosomal acidic endopeptidase. It is an estrogen-regulated protein that is a prognostic factor in breast cancer. The aim of this study was to measure cathepsin D concentrations in thyroid tissues and to correlate these concentrations with clinical and pathologic parameters.

[Management of primary hyperparathyroidism in case of negative cervicotomy].

Negative initial cervicotomy for primary hyperparathyroidism can be due to one of two reasons: first, one gland has not been found: it was an missing adenoma on an ectopic gland. Secondly, four normal glands were found: a missing adenoma arising in a supernumerary and ectopic gland. Successful parathyroid surgery depends the on surgeon's experience, his knowledge of parathyroid gland embryology, and his perseverance to find the pathologic gland.

[Arterial risks in celiosurgery].

It is important to recognize exceptional vascular events in celiosurgery because of their gravity. Most occur during pneumoperitoneal manoeuvres using a Palmer needle and rarely at the insertion of the first trocar. We performed a tomodensitometric study in 200 subjects free of abdominal pathology in order to determine the distance from the umbilicus to the aortic bifurcation, their projection over the spine and the superficial relations of the large vessels to the cutaneous umbilical cover.

[Follow-up of elderly patients previously treated for uncomplicated acute lithiasic cholecystitis].

Surgery is usually indicated in elderly patients with acute lithiasic cholecystitis although single antibiotics are often used for patients over 75 with complex medical histories and major visceral lesions. In our series of 45 patients, no new biliary pathology was seen in 26 (57.8%) after a mean follow-up of 40 months.