170,250 research outputs found
Cylindrical Resonator Sectorally Filled With DNG Metamaterial and Excited by a Line Source
No full textA circular cylindrical resonator with metallic walls is analyzed in the phasor domain. The resonator contains a wedge of double-negative (DNG) metamaterial that is anti-isorefractive to the double-positive (DPS) material filling the remaining volume of the resonator, and whose edge is located on the resonator axis. The resonance conditions are established. The problem of an electric line source parallel to the axis and located anywhere inside the DPS region is solved exactly. Numerical results are presented and discusse
Cylindrical resonator filled with four alternating sectors of DPS and DNG materials
No full textA circular cylindrical metallic resonator with four alternating sectors of DPS and DNG materials is analyzed, in the frequency domain. The two materials are linear, lossless, homogeneous, and anti-isorefractive to each other. The electric field is assumed to be parallel to the cylinder axis. It is also shown that the resonator's dispersion relation is always satisfied for particular geometries. Numerical results for several sectors' combinations will be presented and discussed at the conferenc
Le anomalie dell'arteria epatica in relazione alla chirurgia dell'ipertensione portale
No full textThis study was aimed at investigating the occurrence of hepatic artery variants, at comparing the diagnostic value of duplex Doppler US with that of angiography, and at correlating the results with the technical problems in portal hypertension surgery. All patients were studied with angiography, conventional and duplex Doppler US. In 162 patients with portal hypertension, 38 hepatic artery variants (23.4%) were observed and classified according to Michaels. The commonest variant recognized by angiography was right hepatic artery arising from superior mesenteric artery (type III according to Michaels). US demonstrated hepatic artery variants in 9/162 patients (5.5%). At surgery, variants were found in 3/162 subjects (1.8%) and caused surgical problems in 2 of them (1.2%) - i.e., right hepatic artery arising from superior mesenteric artery. Arteriography is still the best examination to depict hepatic artery variants, while duplex Doppler US demonstrates only a few types. Moreover, the number of variants detected by imaging techniques (23.4%) differs greatly from that observed at surgery (1.8%). Finally, hepatic artery variants are not correlated with surgical problems, nor can the latter be foreseen by imaging methods. US is useful but not essential to detect hepatic artery variants which are subsequently confirmed by angiography
Confronto tra porto-TC e Lipiodol-TC nella stadiazione del carcinoma epatocellulare.
No full textEighteen patients (13 men and 5 women) with uni- and multifocal hepatocellular carcinomas (HCC) were examined. Mean patients age was 63.3 years (range: 47-74 years). All patients had alcoholic or posthepatitis cirrhosis; they were submitted to both CT during arterial portography (APCT) and Lipiodol-CT. The diagnosis of HCC was confirmed by fine-needle biopsy (FNB) in all cases. APCT and Lipiodol-CT results were compared for number, size and site of lesions-32 lesions in all. APCT demonstrated all the lesions: 9 of them were smaller than 2 cm, 14 ranged 2-5 cm and 9 were bigger than 5 cm; moreover, APCT demonstrated other lesions in 3/18 patients (16.6%) which had been missed by US, CT and angiography. Also Lipiodol-CT demonstrated all the 32 lesions and showed smaller lesions in 4/18 patients (22.2%); these nodules were smaller than 2 cm. Based on APCT results 11/18 patients (61.1%) were considered operable, vs. 7/18 patients (38.8%) based on Lipiodol-CT results. To conclude, both APCT and Lipiodol-CT are useful in the preoperative staging of HCC; Lipiodol-CT is preferable to APCT in the study of lesions smaller than 2 cm
Electromagnetic oblique scattering by a cylinder coated with chiral layers and anisotropic jump-immittance sheets
No full textNext-generation lung cancer surgery: a brief trip into the future of the research
No full textLung cancer is the third most frequent cancer and the leading cause of cancer-related mortality worldwide
L'ecotomografia nella cirrosi epatica e nell'ipertensione portale
No full textThe study of liver cirrhosis and portal hypertension by usual real-time ultrasound imaging allows to point out immediately essential signs especially if you consider hepatic surface and parenchymal echotexture, caliber changes in the splenic vein, size of the spleen, collateral veins and ascites
Estrusioni ortodontiche settoriali per la stabilizzazione post-riduttiva di un caso di lussazione temporo-mandibolare
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