We simulate the spin-flip current and transmission function through rings containing elements with a spin–orbit interaction. In a previous study (J. Chem. Phys. 123 (2005) 204714) we predicted that such a system can show spin-birefringence, i.e., a spin current polarized parallel to the molecular axis can flip its direction due to a phase lag due to the spin–orbit interaction. Here we demonstra...

Using parameter values relevant to polyacetylene and its finite polyene analogs, we determine, via exact finite size diagonalization of a 1D Peierls-Hubbard model, the relaxed geometry and optical absorption spectra of several states of interest in optical experiments (the singlet (1Ag) and triplet (1Bu) ground states, the singlet one (n Bu) and two (2 Ag) photon gaps, and the triplet one (n Ag...

In this work we have calculated the electronic states of the trans-polyacetylene (t-PA) molecule within the framework of Density Functional Theory (DFT). For this purpose we have used SIESTA code based on the DFT within the Local Density Approximation (LDA). Fully self-consistent Kohn-Sham functional was performed. We used the Ceperley-Alder (CA) form of the exchange-correlation Potential in LD...

The use of fractal geometries has significantly impacted many areas of science and engineering; one of which is antenna. Designing antenna using fractal geometries has been shown to improve several antenna features. Moment method based simulation code was applied to perform a detailed parametric study for H-Shape model. The use of this model reduces the size of a resonant antenna compared with ...

Two new polyacetylenes, callyspongenol-D (1) and callyspongendiol (2), the known polyacetylene dehydrosiphonochalynol (3), and the known triterpenoid sipholenol-A (4) were isolated from the Red Sea sponge Siphonochalina siphonella. Their chemical structures were elucidated on the basis of spectroscopic analyses. The cytotoxicity of the isolated compounds towards the human mammary carcinoma cell...

We investigated the effects of capillin, a constituent of Artemisia monosperma, on four human tumour cell lines: colon carcinoma H729, pancreatic carcinoma MIA PaCa-2, epidermoid carcinoma of the larynx HEp-2 and lung carcinoma A549. Cells were treated with capillin to examine both the anti-proliferative and pro-apoptotic effects, as well as the molecular mechanism underlying these effects. Cha...