ABSTRACT
The capability to detect traces of explosives sensitively, selectively and rapidly could be of great benefit for applications relating to civilian national security and military needs. Here, we show that, when chemically modified in a multiplexed mode, nanoelectrical devices arrays enable the supersensitive discriminative detection of explosive species. The fingerprinting of explosives is achieved by pattern recognizing the inherent kinetics, and thermodynamics, of interaction between the chemically modified nanosensors array and the molecular analytes under test. This platform allows for the rapid detection of explosives, from air collected samples, down to the parts-per-quadrillion concentration range, and represents the first nanotechnology-inspired demonstration on the selective supersensitive detection of explosives, including the nitro- and peroxide-derivatives, on a single electronic platform. Furthermore, the ultrahigh sensitivity displayed by our platform may allow the remote detection of various explosives, a task unachieved by existing detection technologies.
ABSTRACT
The communication presents DFT calculations of 10 different C-H hydroxylation barriers by the active species of the enzyme cytochrome P450. The work demonstrates the existence of an excellent barrier-bond energy correlation. The so-obtained equation of the straight line is demonstrated to be useful for predicting barriers of related C-H activation processes, as well as for assessing barrier heights within the protein environment. This facility is demonstrated be estimating the barrier of camphor hydroxylation by P450cam.
Subject(s)
Alkanes/chemistry , Cytochrome P-450 Enzyme System/chemistry , Iron Compounds/chemistry , Alkanes/metabolism , Benzene Derivatives/chemistry , Benzene Derivatives/metabolism , Camphor 5-Monooxygenase/chemistry , Camphor 5-Monooxygenase/metabolism , Cytochrome P-450 Enzyme System/metabolism , Ferric Compounds/chemistry , Ferric Compounds/metabolism , Hydrogen/chemistry , Hydrogen/metabolism , Hydroxylation , Iron Compounds/metabolism , Phenols/chemistry , Phenols/metabolism , ThermodynamicsABSTRACT
A novel electrochemical method for deposition of ZrO(2) thin films is described. The films, 50-600 nm thick, were obtained by applying moderate positive or negative potentials (+2.5 V to -1.5 V versus SHE) on conducting surfaces immersed in a 2-propanol solution of zirconium tetra-n-propoxide [Zr(OPr)(4)] in the presence of minute quantities of water (water/monomer molar ratios in the range of 10(-5) to 10(-1)), which was the limiting reagent. Oxidative electrochemical formation of solvated H(+) and reductive formation of OH(-) catalyze the hydrolysis and condensation of the metal alkoxide precursor. The magnitude of the applied potential and its duration provide a convenient way of controlling the film thickness. The films consist of an amorphous phase, as revealed by XRD measurements. The effects of different parameters, such as the applied potential and its duration, the amount of added water and the current-time characteristics, were studied. A mechanism for the electrodeposition of the zirconia films which is in accordance with our findings is proposed.
