Cool vapors and aerosols produced by several common surgical power instruments and hot smoke plumes generated with electrocautery on known HIV-1 innoculated blood were gently bubbled through sterile viral culture media. Tissue culture cells were then added and cell infection was detected by the appearance of HIV-1 P-24 core antigen assayed by ELISA in the culture medium. HIV-1 was cultured from cool aerosols and vapors generated by a 30,000 RPM spinning router tip, an instrument similar to the Midas Rex and the Stryker oscillating bone saw. No infectious HIV-1 was detected in aerosols generated by a Valley Lab electrocautery or with a manual wound irrigation syringe known as a Travenol Uromatic irrigator. We have demonstrated that HIV-1 can remain viable in cool aerosols generated by certain surgical power tools and this raises the possibility of HIV transmission to medical personnel exposed to aerosols similarly generated during the care of HIV infected patients. Further work is required to determine whether such a risk exists but caution should be exercised by those exposed to aerosols generated during procedures on HIV-1 infected patients.

X-ray diffraction contrast tomography ͑DCT͒ is a technique for mapping grain shape and orientation in plastically undeformed polycrystals. In this paper, we describe a modified DCT data acquisition strategy which permits the incorporation of an innovative Friedel pair method for analyzing diffraction data. Diffraction spots are acquired during a 360°rotation of the sample and are analyzed in terms of the Friedel pairs ͑͑hkl͒ and ͑hkl͒ reflections, observed 180°apart in rotation͒. The resulting increase in the accuracy with which the diffraction vectors are determined allows the use of improved algorithms for grain indexing ͑assigning diffraction spots to the grains from which they arise͒ and reconstruction. The accuracy of the resulting grain maps is quantified with reference to synchrotron microtomography data for a specimen made from a beta titanium system in which a second phase can be precipitated at grain boundaries, thereby revealing the grain shapes. The simple changes introduced to the DCT methodology are equally applicable to other variants of grain mapping.

No abstract

The diet, attributes of feeding sites and patterns of seasonal movements of a population of the Gouldian finch, Erythrura gouldiae, were studied in the Yinberrie Hills area north of Katherine in the Northern Territory. In the dry season (April–November) Gouldian finches foraged mostly on burnt ground and fed on exposed seed of annual grasses, especially seed of spear-grass, Sorghum spp. In the wet season (December–March) Gouldian finches fed on seed of a sequence of perennial grass species, including Themeda triandra, Alloteropsis semialata, Chrysopogon fallax and Heteropogon triticeus. Gouldian finches undertake regular seasonal shifts in habitat, from breeding areas in hill woodland in the dry season to adjacent lowlands throughout much of the wet season, in response to seasonal changes in food availability. There is an annual pulse in abundance of fallen seed in the early dry season that is depleted to near zero levels by germination of annual grasses early in the wet season. Thereafter, finches depend on seed from other sources, principally ripe and ripening seed of perennial grasses. Observations over three successive wet seasons suggest that Gouldian finches track seed resources provided by seeding perennial grasses over an extensive area of lowland grassy woodland adjacent to the breeding area, favouring small patches of grassy woodland for brief periods until seed fall. There were subtle differences between years in the types of resources used. Management of Gouldian finch populations will entail protection and management of the full range of grassland habitats used throughout the annual cycle, and will require predictive knowledge of the causes of patterning of seed resources and probably an ability to exert control over the timing and extent of fires in fire-prone seasonal savanna landscapes.

A systematic framework for estimating the uncertainty associated with measurements of finite stretch and orientation of a crystalline lattice using monochromatic X‐ray diffraction is presented. A hierarchical method is implemented, in which uncertainties in the locations of diffraction peaks are communicated to the lattice stretch and rotation parameters by using the classical method of weighted least squares. This enables the uncertainty of the lattice stretch and rotation parameters to be estimated from a single full rotation scan. This method is applied to diffraction data obtained from a ruby single crystal as an idealized case for validation, and an example application is demonstrated by analyzing a strained and plastically deformed polycrystalline titanium alloy, β21S. For the ruby single crystal, it was possible to attain average uncertainties for lattice orientation and strain that were found to be comparable to standard statistical analysis of repeated measurements. For the titanium alloy, a single grain was analyzed, and a precision of 0.03° for lattice orientation and 100–250 × 10−6 for lattice strain components was obtained. The basic framework of the uncertainty analysis is generally applicable, although specific results are unique to monochromatic X‐ray diffraction experiments.