The substituent effect on nonlinear current voltage characteristics in a two-terminal molecular electronic device

We present a quantum mechanical tunneling model for electron transport through a molecular junction and address the model with the results of quantum chemical electronic structure calculations. The model gives insight into the origin of the substituent effect on the current versus applied voltage characteristics of molecular junctions.

Interactions of hydrogen with CeO(2)

The interactions of hydrogen with ceria have been the subject of several experimental studies, but whether hydrogen atoms enter the bulk or are merely chemisorbed on the surfaces is disputed. We combine first-principles calculations with thermodynamic arguments and conclude that the uptake of small amounts of hydrogen by ceria is spontaneous below 665 K. The calculations also predict that hydrogen atoms within the bulk form hydroxyl groups and slightly expand the lattice. The predicted hydrogen content, OH vibrational frequency, and ceria lattice expansion upon hydrogen uptake are consistent with available data.

Nonstoichiometry and the electrical activity of grain boundaries in SrTiO3

A combination of experiments and first-principles calculations is used to show that grain boundaries in SrTiO3 are intrinsically nonstoichiometric. Total-energy calculations reveal that the introduction of nonstoichiometry into the grain boundaries is energetically favorable and results in structures that are consistent with atomic-resolution Z-contrast micrographs. Electron energy-loss spectra provide direct evidence of nonstoichiometry. These results and calculations for nonstoichiometric grain boundaries provide an explanation of the microscopic origin of the "double Schottky barriers" that dominate the electrical behavior of polycrystalline oxides.

Surface reconstruction and the difference in surface acidity between gamma- and eta-alumina

The surfaces of the gamma and eta forms of alumina are well known to differ significantly in Lewis acidity. Surface reconstructions observed on gamma- and eta-alumina are also qualitatively different, despite the close similarity of the bulk structures. Here we demonstrate through first-principles calculations that subtle differences in the bulk point defect distribution between these two forms of alumina give rise to the major differences in the mode of surface reconstruction and correlate with the different levels of Lewis acidity.

Reversible, nanometer-scale conductance transitions in an organic complex

Reversible conductance transitions are demonstrated on the molecular scale in a complex of 3-nitrobenzal malononitrile and 1, 4-phenylenediamine, by application of local electric field pulses. Both macroscopic and local current-voltage (I/V) measurements show similar electrical bistability behavior. The mechanism of the electrical bistability is discussed.

Fatal congestive heart failure following mitoxantrone treatment in two children previously treated with doxorubicin and cisplatin

Two children, who had received chemotherapy with doxorubicin and cisplatin for disseminated chondrosarcoma and recurrent rhabdomyosarcoma, developed congestive heart failure following treatment with mitoxantrone (DHAD); the total doses of DHAD were 128 and 90 mg/m2, respectively. The patient with chondrosarcoma had relief of his cardiac symptoms with digitalis and furosemide. The patient with rhabdomyosarcoma, whose tumor responded following treatment with DHAD, died 2 weeks after development of congestive heart failure. For patients who have received prior treatment with potentially cardiotoxic agents, administration of DHAD should be followed by careful monitoring of cardiac function.