Morphological importance of coronary ostia in equine.

The position of the coronary ostia was investigated in 70 segments of the aorta from young adult crossbred horses. After fixation with a 4% buffered aqueous formaldehyde solution and cautious dissection of the aortic bulb, the morphometric relationships between the coronary ostium and the aortic valvar elements were digitally analysed with the support of Image-Pro Plus® software. In horses, the left coronary ostium was near to the right valvular commissure in all cases (100%) analysed in this study. The left coronary ostium was at the level of the intercommissural line in 57.1% and below it in 42.9%. The right coronary ostium was near to the left valvular commissure in 58.6% (2.14 ± 0.32 cm) and close to the right valvular commissure in 41.4% (2.27 ± 0.40 cm). Concerning the intercommissural line, the right coronary ostia was at its level in 24.3% and below it in 75.7%. Accessory coronary ostia were observed in 8.6% of the specimens. In view of the results, it was possible to assume that the positions of the coronary ostia in equines tend towards a standard morphological disposition. Thus, perfusion of the left coronary artery occurs partly more frequently in ventricular systole and complete perfusion occurs less frequently in ventricular diastole. For the right coronary artery, perfusion is mostly complete in diastole and partially in ventricular systole.

Anisotropic self-organization of hybrid silica based xerogels containing bridged positively charged 1,4-diazoniabicycle[2.2.2]octane chloride group.

Anisotropic self-organized hybrid silica based xerogels were obtained. The ordered structure was imposed by the double charged 1,4-diazoniabicycle[2.2.2]octane chloride group bonded in a bridged way. This was confirmed by the presence of well defined X-ray diffraction peaks corresponding to an interplanar distance with the same length estimated for the organic bridged groups. The material was characterized by elemental analysis using CHN technique and the chloride ion was analyzed by a potentiometric titration. (13)C and (29)Si CP MAS solid state NMR spectroscopy and thermogravimetric analysis were also performed. The material that can be obtained in the form of powders and transparent monoliths or films, is thermally stable up to 260 degrees C and the samples with high organic content presented birefringence properties.