The diet-induced atherosclerotic rabbit is an ideal model for atherosclerosis study, but temporal changes in atherosclerotic development in hypercholesterolemic rabbits are poorly understood. ...Japanese white rabbits were fed a high-cholesterol diet to induce sustained hypercholesterolemia, and each group of 10–12 animals was then sacrificed at 6, 12, 16, or 28 weeks. The rabbit aortas were harvested, and the sizes of the gross and intima atherosclerotic lesions were quantified. The cellular component of macrophages (Mφs) and smooth muscle cells (SMCs) in aortic intimal lesions was also quantified by immunohistochemical staining, and the correlation between plasma cholesterol levels and the progress of atherosclerotic lesions was studied. The ultrastructure of the atherosclerotic lesions was observed by transmission electron microscopy (TEM). Widely variable atherosclerotic plaques were found from 6 weeks to 28 weeks, and the lesional progress was closely correlated with cholesterol exposure. Interestingly, a relatively reduced accumulation of Mφ, an increased numbers of SMCs, and a damaged endothelial layer were presented in advanced lesions. Moreover, SMCs were closely correlated with cholesterol exposure and lesional progress for the whole period. Cholesterol exposure directly determines atherosclerotic progress in a rabbit model, and the changes in the cellular component of advanced lesions may affect plaque stability in an atherosclerotic rabbit model.
Since satellite communications have developed towards personal and mobile communication, they become indispensable portions in global communications. Transmission power and available frequency band ...are restricted by the satellite inherent characteristic. So, a new resource management strategy is required for satellite communications. Spot beam technique is widely adopted in satellite systems, building a overlapped beams architecture (OBA), with its frequency reuse just as in terrestrial cellulars, in which entire spectrum is orthogonally assigned to adjacent beams, leading to a relatively low spectrum utilization. In this paper, a new multi-layer beam architecture (MBA) is proposed. We analyze the system performance by calculating global reuse factor, system maximum achievable rate and blocking probability. Numerical results suggest that MBA outperforms the original OBA in the metrics above, making better utilization of frequency spectrum.
Current distribution of a tower on lightning stroke Peng Li; Yinghua Lv; Ning Liu ...
2011 4th IEEE International Symposium on Microwave, Antenna, Propagation and EMC Technologies for Wireless Communications,
2011-Nov.
Conference Proceeding
An original circuit model is presented for analyzing current distribution of a tower on lightning stroke. Electrical parameters of steels are determined by a serial of approximate calculating. ...Several profound references are provided - the earth resistivity and the lightning position can not affect the branch current of antenna cable jacket; grounding conductor's current is only determined by the conductor's location.
The cardioprotective effects of melatonin on recovery of rat donor hearts after 12 h of preservation were investigated. Wistar rats weighing 200 to 250 g (n=24) were randomly divided into 3 groups. ...In the non-storage group (n=8), donor hearts were not stored. In the melatonin group (n=8), donor hearts were stored in 4 degrees C St. Thomas solution with melatonin (0.1 mmol/L). In the control group (n=8), donor hearts were stored in 4 degrees C St. Thomas solution only. The coronary flow (CF), cardiac function, coronary vasodilatory response, creatine kinase (CK) and high energy phosphate levels were measured after the hearts had been preserved for 12 h. Transmission electron microscopy was used to examine the microstructural changes after 12 h of preservation. The recovery of cardiac function and coronary vasodilatory response were significantly improved in the melatonin group (P<0.01). CK release decreased greatly in the melatonin group (P<0.01). High energy phosphate levels were significantly better preserved in the melatonin group (P<0.01). Histological findings were much better in the melatonin group than in the control group. These results suggest that melatonin has cardioprotective effects on the recovery of rat donor hearts after 12 h of preservation.
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