This study investigates the permeability-porosity relationship for glass and natural fiber mats. The estimation of the permeability-porosity relationship for glass mats is not new and has been investigated before by several authors, but in the present paper the same relationship was discovered for natural fibers. The experimental permeability values were fitted by the Carman-Kozeny equation with two fitting parameters: the Kozeny constant and the exponent of the porosity. The obtained permeability for the natural fiber mats shows higher values than glass fiber mat.

Background. There are several clinical situations in which large epicardial coronary arteries are deprived of blood flow, such as occurs when an obstructing thrombus or embolus lodges within a vessel or during coronary dissection. There is little information concerning the effect of flow deprivation on large epicardial coronary arteries.Methods and Results. We studied a model in which a segment of a large epicardial coronary artery was deprived of blood flow using both proximal and distal clamps for 3 hours followed by reperfusion. On examination by light microscopy of cross sections of the arteries, 19±t6 neutrophils were present in the intima of ischemic/reperfused vessels, whereas only a mean of 4±3 (SEM) were present in the intima of nonischemic vessels (p<0.02). On average, there were 17±9 neutrophils just under the elastic lamina in ischemic/reperfused vessels versus none in the nonischemic vessels (p<0.05); there were 16± 10 neutrophils present within the media of ischemic/reperfused vessels, and none (p<0.05) in the nonischemic vessels. Electron microscopic analysis revealed that neutrophils in the ischemic/reperfused vessels were often "sandwiched" between the endothelial cells and the elastic lamina. Ultrastructural abnormalities within the myocardium also revealed damage to the microvasculature, including the presence of neutrophils within the vessels and erythrocyte stasis. To rule out the possibility that

The LASGB operation is safe and effective, and deserves wider use for treatment of morbid obesity.