A 47-year-old man presented with carotid rete mirabile manifesting as subarachnoid hemorrhage (SAH). Computed tomography showed SAH, and angiography disclosed an abnormal vascular network around the petrous and cavernous portions of the internal carotid artery. Single photon emission computed tomography (SPECT) with technetium-99m methyl cysteinate dimer revealed reduced regional cerebral blood...

A method for probing the strength of B-N dative bonds is reported. The activation parameters for nitrogen inversion in a series of azetidines tethered to boronate esters have been quantified by VT-NMR and the measured barriers correlated with data obtained by (11)B NMR, X-ray crystallography and MP2 calculations.

Enzyme kinetics for systems biology should ideally yield information about the enzyme's activity under in vivo conditions, including such reaction features as substrate cooperativity, reversibility and allostery, and be applicable to enzymatic reactions with multiple substrates. A large body of enzyme-kinetic data in the literature is based on the uni-substrate Michaelis-Menten equation, which ...

Nuclear magnetic resonance (NMR) spectroscopy is widely used for profiling of a variety of complex biological samples. The advantages of NMR are its quantitative and nondestructive nature, high reproducibility and that measurements can be done with minimal sample preparation and instrument calibration. However, accurate quantification of compounds from a 1H NMR spectrum of biological sample, wh...

the n-(2-benzoyl-phenyl) oxalyl derivatives are important models for studying of three-centered intramolecular hydrogen bonding in organic molecules. the quantum theoretical calculations for two crystal structures of n-(2-benzoyl-phenyl) oxalyl (compounds i and ii) were performed by density functional theory (b3lyp method and 6-311+g* basis set). from the optimized structures, geometric paramet...

The three-dimensional structure of a cyclic enterobacterial common antigen (ECA) having four trisaccharide repeating units has been investigated by NMR spectroscopy and molecular dynamics simulations. Three different NMR parameters were determined: (a) (1)H,(1)H cross-relaxation rates from NOE experiments were used for determination of proton-proton distances; (b) trans-glycosidic (3)J(C,H) sca...