The syntheses and halogen bonded (XB) complexes of tetrahalogenated ethynyl cavitands are presented. These cavitands act as quite rigid 3D multivalent halogen bond donors and show strong XB with oxygen, nitrogen and bromide XB acceptors.

[reaction: see text] We report for the first time that stoichiometric and even catalytic quantities of weak acids in aqueous solution can very efficiently catalyze amide isomerization in a carefully designed system in which a proton donor is situated so that intramolecular hydrogen bonding to the amide nitrogen is highly favored. Our results provide the first experimental verification that hydr...

We study the mutual passivation of shallow donor and isovalent N in GaAs. We find that all the donor impurities, SiGa, GeGa, SAs, and SeAs, bind to N in GaAs:N, which has a large N-induced band-gap reduction relative to GaAs. For a group-IV impurity such as Si, the formation of the nearest-neighbor SiGa-NAs defect complex creates a deep donor level below the conduction band minimum (CBM). The c...

A challenge for photobiological production of hydrogen gas (H(2)) as a potential biofuel is to find suitable electron-donating feedstocks. Here, we examined the inorganic compound thiosulfate as a possible electron donor for nitrogenase-catalyzed H(2) production by the purple nonsulfur phototrophic bacterium (PNSB) Rhodopseudomonas palustris. Thiosulfate is an intermediate of microbial sulfur m...

Nitrogen balances were measured in isolated perfused rat livers in the presence and absence of nitrogen donors. In all instances the balance apparently was incomplete. The expression [alanine][alpha-oxoglutarate]/[pyruvate][glutamate] remained fairly constant under the metabolic conditions studied, indicating that it may be at near-equilibrium. The source of the extra nitrogen seems to be deriv...

The aim of this study was to investigate the normal values of glomerular filtration rate (GFR) by technetium-99m diaethylene-triamine-pentaacetic acid ((99m)Tc-DTPA) renal dynamic imaging for living kidney graft donors. In a total of 212 candidate donors, GFR was examined using (99m)Tc-DTPA renal dynamic imaging. Donors with GFR≥80mL/(min×1.73m(2)) and as low as with GFR≥70mL/(min×1.73m(2)) but...

Hall measurements on four n-type cubic SiC films epitaxially grown by chemical vapor deposition on (100) SiC substrates are reported. Detailed analyses of the temperature dependent carrier concentrations indicate that the samples are highly compensated (>90 percent), contrary to the assumption of no compensation made in previous studies of similarly prepared SiC films. Donor ionization energies...

The characteristics of the generation-recombination (g-r) process in silicon are investigated a temperature range from 25 to 360 K. In case shallow donors, it is shown that free electron density strongly depends on temperature: only 20% donors ionized at donor densities about 10 17 cm -3 liquid nitrogen temperature. maximum variance noise due fluctuations for sample with increases and shifts It...