ABSTRACT
A unique paradigm for intermolecular charge transport mediated by diffuse atomic-like orbital (SAMOs), typically present in conjugated hollow shaped molecules, is investigated for C20H10 molecular fragments by means of G0W0 theory. Inclusion of many body screening and polarization effects is seen to be important for accurate prediction of electronic properties involving these diffuse orbitals. Theoretical predictions are made for the series of bowl-shaped fullerene fragments, C20H10, C30H10, C40H10, C50H10. Interesting results are found for the LUMO-SAMO energy gap in C20H10, which is shown to be nearly an order of magnitude lower that that determined for C60. Given the ability to support bowl fragments on metal surfaces, these results suggest the concrete possibility for exploiting SAMO-mediated electron transport in supramolecular conducting layers.
ABSTRACT
The expression of the neural cell adhesion molecule (NCAM) was studied in normal human myocardium and in Chagas' disease myocarditis. We found that NCAM is expressed in the conduction system as well as the myocardium in the fetal heart, but its expression is restricted to the conduction system and absent in the adult myocardium. Chagas' disease is an American endemic disease caused by the Trypanosoma cruzi parasite, which produces myocarditis and a blockade of the conduction system, resulting in cardiac dysfunction. We studied the expression of NCAM in paraffin-embedded human heart tissues from 34 autopsies of patients with Chagas' myocarditis and from murine and canine experimental acute Chagas' myocarditis, using a polyclonal anti-NCAM antibody and immunohistochemistry. Our results show a dramatic upregulation of NCAM expression in the intercalated discs of cardiomyocytes in acute and chronic Chagas' myocarditis. Surprisingly, the NCAM signal was detected in intracellular nests of amastigote forms of the parasite, within infected cardiomyocytes of human and experimental Chagas' myocarditis. In contrast, cardiac cell-cell adhesion proteins, N-cadherin and beta-catenin, were found in intercalated discs distorted by the infection but absent from the amastigote nests. Proteins reactive to several antibodies against NCAM were detected by Western immunoblotting in cultured T cruzi parasites and in trypomastigote forms of T cruzi extracted from the blood of infected mice. The upregulation of NCAM in Chagas' myocarditis and the expression of NCAM or a NCAM-like protein by T cruzi suggest that NCAM may act as a receptor for tissue targeting and cellular invasion by T cruzi in Chagas' disease.
