RESUMO
We report the synthesis of sulfonated copolyaniline/polysafranin/L-ascorbic acid/Ag@SiO2 fine powdered nanocomposites and investigate the influence of incorporating the dye on their conductivity. The composite was characterized via IR, UV, cyclic voltammetry (CV), electric, dielectric, SEM, TEM, TGA and DSC measurements. Microscopy images revealed intensified spherical particles that were dispersed across the entire surface, and the SiO2/Ag particles were distributed on the surface. The XRD results exhibited peaks at many 2q values, and their interatomic spacing (d) and crystallite (grain) sizes were calculated. The thermal degradation curves exhibited an interesting model of stability. The cyclic voltammogram exhibited redox peaks identical to those of the reported analogues. The d.c. conductivity of the oligomer varied from 0.06 - 0.016 (s/cm), and that of the composite varied from 0.008 to 0.016 (s/cm). The material changed from a semiconductor to a metallic material. The observed conductivity is mainly attributed to self-doping between the sulfonate groups and the charged nitrogen atoms in the polymer chains. The frequency dependence of the permittivity, ε', showed a marked effect on the frequency window under consideration. The permittivity, ε', is independent of the increase in the frequency of the oligomer and the composite. This behavior supports the non-Debye dependency by confirming the occurrence of electrode polarization and space charge effects. In conclusion, the incorporation of safranin dye with a thermally stable, highly sulfonated polyaniline derivative/Ag@SO2 nanocomposite achieved improved conductivity after heating. The d.c. conductivities are comparable to those of many commercial inorganic or organic composites, and because of their attractive electrical properties, we suggest that these materials are promising for electronic field applications.
RESUMO
INTRODUCTION: Cases of primary neuroendocrine tumors in the liver combined with hepatocellular carcinoma are scarce. Such cases could present either as combined-type tumor or collision type. PRESENTATION OF CASE: A 51-year-old man presented with a mass in the right hemiliver. Serum level of alpha-fetoprotein was slightly elevated (2.3ng/ml), with normal CA19-9 and CA125. The patient underwent right hepatectomy. The resected specimen showed a well-defined and heterogeneous gray-white to brown friable tumor, 20cm in diameter. Microscopically, the tumor consisted predominantly of monotonous small- to medium-sized neoplastic cells arranged in trabeculea separated by sinusoidal spaces. Immunohistochemically, the tumor cells were strongly positive for synaptophysin and focally positive for chromogranin-A. Interestingly, the tumor cells showed patchy positive coarse granular staining of HerPar-1 involving about 1% of the tumor cells. Glypican-3 staining was negative. These immunohistochemical findings supported the diagnosis of combined high grade neuroendocrine carcinoma and hepatocellular carcinoma. DISCUSSION: Cases of primary neuroendocrine tumors in the liver combined 82 with hepatocellular carcinoma are scarce. The uniqueness of this case lies in the fact that the neuroendocrine carcinoma component comprised more than 99% of the tumor area, and the minor hepatocellular carcinoma component was detected only by the immunohistochemical staining for HepPar-1. CONCLUSION: To the best of our knowledge, this is the first case of combined neuroendocrine carcinoma and hepatocellular carcinoma in Egypt.
