Subtle structural details of siliceous zeolites are probed by using two-bond scalar (J) coupling constants to characterize covalently bonded Si–O–Si site pairs and local framework order. Solid-state two-dimensional (2D) Si{Si} NMR measurements and first-principles calculations of J(Si–O–Si) couplings shed insights on both the local structures of siliceous zeolites Sigma-2 and ZSM-12, as well as...

Novel organosilylated tetrathiafulvalenes (TTFs) possessing Si-H or Si-Si bonds have been synthesised. The crystal structures of several derivatives have been determined by X-ray diffraction, including that of dimeric (Si2Me4)(TTF)2 (11) incorporating a diatomic SiMe2-SiMe2 linker. Cyclic voltammetry measurements in all cases show two oxidation waves. DFT calculations were performed to rational...

Following the complete sequencing of the Escherichia coli genome, it has been shown that the proposed second citrate synthase of this organism, recently described by the authors, is in fact a 2-methylcitrate synthase that possesses citrate synthase activity as a minor component. Whereas the hexameric citrate synthase is constitutively produced, the 2-methylcitrate synthase is induced during gro...

In this work, we present our preliminary ab initio results for the structural and electronic properties of both Siand C-terminated SiC (100) surfaces in (2×1) and c(2×2) reconstruction patterns. Based on our results, we found that the Si-terminated surfaces are dominated by weak bonded Si-dimers, which are stabilized only at Si-rich conditions, leading to (3×2) or more complex reconstruction pa...

BACKGROUND AND PURPOSE Prior reports have described increased signal intensity (SI) of CSF on fluid-attenuated inversion recovery (FLAIR) images of anesthetized patients receiving 100% O(2). This appearance can simulate that of diseases. We evaluated the relationship between the concentration of inhaled O(2) and the development of increased SI of CSF on FLAIR images. METHODS FLAIR was perform...

A simple method was found for the fabrication of silver nanosheets (AgNS) by the catalysis of gold nanoparticles (AuNP) on an amine-terminated cubic boron nitride (cBN) surface deposited on a Si(001) substrate in the presence of reductant. The morphology of the AgNS/AuNP/NH(2)-cBN/Si(001) sample was characterized by scanning electron microscopy and X-ray diffraction. The performance of the AgNS...