Intermediate (VISA-type) vancomycin resistance in Staphylococcus aureus has been associated with a range of physiologic and genetic alterations. Previous work described the emergence of VISA-type resistance in two clonally-distinct series of isolates. In both series (the first belonging to MRSA clone ST8-USA300, and the second to ST5-USA100), resistance was conferred by a single mutation in yvq...

We examined the molecular mechanisms of resistance to kanamycin and viomycin in Mycobacterium smegmatis. All of the M. smegmatis strains with high-level kanamycin resistance had a nucleotide substitution from A to G at position 1389 of the 16S rRNA gene (rrs). This position is equivalent to position 1408 of Escherichia coli, and mutation at this position is known to cause aminoglycoside resista...

Background: The equivalent dose in the human body due to the natural gamma-emitting radionucides (238U, 232Th and 40K) in the surface soil surrounding the Consolidated Tin mine site in Bukuru-Jos, Nigeria has been determined in this study. Materials and Methods: Measurements of the soil natural radioactivity were made using a multi-channel pulseheight analyzer (Canberra Series 10 plus) coupled ...

The pyroxene composition of basaltic rocks from the Coloured Series and Exotic blocks in the Neyriz area are discussed. Comparison has been made with equivalent rocks from Oman. The clinopyroxene compositions are in cognation with trace and rare-earth element analyses which definately confirm the occurrence of three different trends in basic lavas: I-Depleted tholeiite, 2-Transitional basal...

The proton conductivity of a series of extruded Nafion membranes @of equivalent weight ~EW! of 1100 and nominal dry thickness of 51, 89, 127, and 178 mm# has been studied. Measurements were made in 1 M H2SO4 at 298 K using a four-electrode, dc technique. The membrane area resistance increases with thickness, as expected, from 0.07 to 0.16 V cm for Nafion 112 and Nafion 117, respectively. Howeve...

Four-probe impedance spectra of polycrystalline cation conductors: NASICON, Na b0-alumina and Ag b0-alumina, were measured in the frequency range from 10 Hz to 100 kHz with the aid of high sensitivity, high input impedance preamplifiers. Dispersion associated with the grain boundary polarization was observed below room temperature. The frequency dependent part of the conductivity of grain inter...

An electrical equivalent circuit is derived for the electrospray process. It is a series circuit which consists of the power supply, the electrochemical contact to the solution, the solution resistance (R(s)), a constant-current regulator which represents the processes of charge separation and charge transport in the gap between the spray needle aperture and the counter electrode, and charge ne...