Hydrogen sensors based on electrophoretically deposited Pd nanoparticles onto InP

Electrophoretic deposition of palladium nanoparticles prepared by the reverse micelle technique onto InP substrates is addressed. We demonstrate that the substrate pre-deposition treatment and the deposition conditions can extensively influence the morphology of the deposited palladium nanoparticle films. Schottky diodes based on these films show notably high values of the barrier height and of the rectification ratio giving evidence of a small degree of the Fermi level pinning. Moreover, electrical characteristics of these diodes are exceptionally sensitive to the exposure to gas mixtures with small hydrogen content

External decontamination of wild leeches with hypochloric acid

BACKGROUND: Medicinal leech, Hirudo medicinalis, has been used in plastic and reconstructive surgery, to relieve venous congestion and to improve the microrevascularization of flaps. In many countries, wild leeches are still provided from local markets and utilised with antibiotic prophylaxies. In this research, results of identification of bacteria in the transport fluid is reported, oral and intestinal floras and the antibiograms of the identified microorganisms are investigated. Also, to avoid possible infections, the ability of hypochloric acid, a disinfectant, to suppress the relevant microorganisms without changing the life style and behavior of leeches in terms of sucking function, is investigated. METHODS: Bacterial identifications and antibiograms of oral and intestinal flora and transport medium were performed for 10 leeches. The optimum concentration of hypochloric acid which eliminated microorganisms without affecting the viability and sucking function of the leeches were determined by dilution of hypochloric acid to 100, 50, 25, 12.5, 6.25 ppm concentrations in different groups of 25 leeches. Finally, 20 leeches were applied atraumatically to the bleeding areas of rats, the duration of suction was determined and compared statistically between the leeches treated and not treated with hypochloric acid solution. RESULTS: Aeromonas hydrophilia was the most commonly identified microorganism and found to be resistant to first generation cephalosporins, frequently used in prophylaxis at surgical wards. In the next stages of the study, the leeches were subjected to a series of diluted hypochloric acid solutions. Although disinfection of the transport material and suppression of the oral flora of hirudo medicinalis were successful in 100, 50, 25, 12.5, 6.25 ppm concentrations; 12.5 ppm solution was the greatest concentration in which hirudo medicinalis could survive and sucking function was not affected significantly. CONCLUSIONS: External decontamination of wild leeches with 12.5 ppm hypochloric acid enables bacterial suppression without causing negative effects on leech sucking function and life

ATP and its N6-substituted analogues: parameterization, molecular dynamics simulation and conformational analysis

In this work we used a combination of classical molecular dynamics and simulated annealing techniques to shed more light on the conformational flexibility of 12 adenosine triphosphate (ATP) analogues in a water environment. We present simulations in AMBER force field for ATP and 12 published analogues [Shah et al. (1997) Proc Natl Acad Sci USA 94: 3565–3570]. The calculations were carried out using the generalized Born (GB) solvation model in the presence of the cation Mg2+. The ion was placed at a close distance (2 Å) from the charged oxygen atoms of the beta and gamma phosphate groups of the −3 negatively charged ATP analogue molecules. Analysis of the results revealed the distribution of inter-proton distances H8–H1′ and H8–H2′ versus the torsion angle ψ (C4–N9-C1′–O4′) for all conformations of ATP analogues. There are two gaps in the distribution of torsion angle ψ values: the first is between −30 and 30 degrees and is described by cis-conformation; and the second is between 90 and 175 degrees, which mostly covers a region of anti conformation. Our results compare favorably with results obtained in experimental assays [Jiang and Mao (2002) Polyhedron 21:435–438]

(1RS,4RS)-1-methoxyspiro[bicyclo[2.2.2]oct-5-ene-2.2 '-[1 ',3 ']dithiolane]

WOS: 000183875000076The title compound, C11H16OS2, consists of a five-membered dithiolane ring with a methoxybicyclooctene spiro-fused at the 2-position. A few interatomic close contacts seem to influence the geometry of the dithiolane ring

(1RS,4RS)-1-Methoxyspiro[bicyclo[2.2.2]oct-5-ene-2,2 '-[1 ',3 ']dithiolane] (vol E59, pg o926, 2003)

WOS: 00023503370028

(1RS,3RS)-2-Methoxymethyl-1,3-dithiolane 1,3-dioxide

WOS: 000185644100093The title compound, C5H10O3S2, consists of a five-membered dithiolane ring with one O atom bonded to each S atom and a methoxymethyl group at the 2-position. Some interatomic close contacts appear to influence the geometry of the dithiolane ring

Dimethyl 3,6-dioxatetracyclo[6.1.0.0(2,4).0(5,7)]nonane-2,9-dicarboxylate

The title compound, C11H12O6, has a norcarane structure, which is obtained by the photooxygenation reaction of a cycloheptatriene derivative. The cyclohexane ring is planar. The intermolecular C-H center dot center dot center dot O hydrogen bonds are effective in stabilizing the crystal structure, in which they form parallel infinite chains along the b axis

1,1 ',3,3 '-tetraalkyl-2,2 '-biperimidinylidenes: Unexpected substituent effects on the reactivity of carbon-carbon double bond

WOS: 000180824700013C-2 deprotonation of 1,3-dibutylperimidinium bromide (1a) with sodium hydride and a catalytic amount of potassium tert-butoxide in dry THF led to the formation of the exceptionally inert tetraaminoalkene 2a. In contrast, isostructural tetrakis(2-methoxyethyl)-tetraaminoalkene (2b) instantaneously reacted with O-2 to yield urea 3b, and silver nitrate was readily reduced with 2b to form a silver mirror. Compound 2a has been characterized by X-ray diffraction studies; the naphtho-pyrimidine skeleton imposes structural constraints and some rigidity to the C=C bonding. (C) 2003 Wiley Periodicals, Inc