University of Extremadura

About: University of Extremadura is a education organization based out in Badajoz, Spain. It is known for research contribution in the topics: Population & Hyperspectral imaging. The organization has 7856 authors who have published 18299 publications receiving 396126 citations. The organization is also known as: Universidad de Extremadura.

The terminal crest: morphological features relevant to electrophysiology

Abstract: Objective: To investigate the detailed anatomy of the terminal crest (crista terminalis) and its junctional regions with the pectinate muscles and intercaval area to provide the yardstick for structural normality. Design: 97 human necropsy hearts were studied from patients who were not known to have medical histories of atrial arrhythmias. The dimensions of the terminal crest were measured in width and thickness from epicardium to endocardium, at the four points known to be chosen as sites of ablation. Results: The pectinate muscles originating from the crest and extending along the wall of the appendage towards the vestibule of the tricuspid valve had a non-uniform trabecular pattern in 80% of hearts. Fine structure of the terminal crest studied using light and scanning electron microscopy consisted of much thicker and more numerous fibrous sheaths of endomysium with increasing age of the patient. 36 specimens of 45 (80%) specimens studied by electron microscopy had a predominantly uniform longitudinal arrangement of myocardial fibres within the terminal crest. In contrast, in all specimens, the junctional areas of the terminal crest with the pectinate muscles and with the intercaval area had crossing and non-uniform architecture of myofibres. Conclusions: The normal anatomy of the muscle fibres and connective tissue in the junctional area of the terminal crest/pectinate muscles and terminal crest/intercaval bundle favours non-uniform anisotropic properties.

Ozone-Enhanced Oxidation of Oxalic Acid in Water with Cobalt Catalysts. 2. Heterogeneous Catalytic Ozonation

Abstract: Ozone and a Co3O4/Al2O3 catalyst have been used to remove oxalic acid from water at acidic pH. The influence of different variables, including the initial oxalic acid and ozone gas concentrations, the catalyst mass, and the temperature, has been investigated under conditions of chemical control. The ozone efficiency was found to reach values of up to 40%, which are higher than those found in homogeneous catalysis (see also the first part of this work, which immediately precedes this paper in this issue), and the mean stoichiometry was determined to be 0.8 mol of ozone consumed per mole of oxalic acid consumed. Metal leaching was also followed to check the stability of the catalyst. As a result, ozonation of oxalic acid was found to be due to both heterogeneous and homogeneous catalytic ozonation. The average contribution of heterogeneous catalytic ozonation for the removal of oxalic acid was found to be 75%. A kinetic study taking into account both catalytic contributions is also presented. The experiment...