Domain wall conductivity in semiconducting hexagonal ferroelectric TbMnO3 thin films.

Although enhanced conductivity of ferroelectric domain boundaries has been found in BiFeO3 and Pb(Zr,Ti)O3 films as well as hexagonal rare-earth manganite single crystals, the mechanism of the domain wall conductivity is still under debate. Using conductive atomic force microscopy, we observe enhanced conductance at the electrically-neutral domain walls in semiconducting hexagonal ferroelectric TbMnO3 thin films where the structure and polarization direction are strongly constrained along the c-axis. This result indicates that domain wall conductivity in ferroelectric rare-earth manganites is not limited to charged domain walls. We show that the observed conductivity in the TbMnO3 films is governed by a single conduction mechanism, namely, the back-to-back Schottky diodes tuned by the segregation of defects.

Isolated, well-defined organovanadium(iii) on silica: single-site catalyst for hydrogenation of alkenes and alkynes.

A well-defined, isolated, single-site organovanadium(iii) catalyst on SiO2 [(SiO2)V(Mes)(THF)] was synthesized via surface organometallic chemistry, and fully characterized using a combination of analytical and spectroscopic techniques (EA, ICP, 1H NMR, TGA-MS, EPR, XPS, DR-UV/Vis, UV-Raman, DRIFTS, XAS). The catalyst exhibits unprecedented reactivity in liquid- and gas-phase alkene/alkyne hydrogenation. Kinetic poisoning experiments revealed that 100% of the V sites are active for hydrogenation.

Conducting LaAlO3/SrTiO3 heterointerfaces on atomically-flat substrates prepared by deionized-water.

We have investigated how the recently-developed water-leaching method for atomically-flat SrTiO3 (STO) substrates affects the transport properties of LaAlO3 (LAO) and STO heterointerfaces. Using pulsed laser deposition at identical growth conditions, we have synthesized epitaxial LAO thin-films on two different STO substrates, which are prepared by water-leaching and buffered hydrofluoric acid (BHF) etching methods. The structural, transport, and optical properties of LAO/STO heterostructures grown on water-leached substrates show the same high-quality as the samples grown on BHF-etched substrates. These results indicate that the water-leaching method can be used to grow complex oxide heterostructures with atomically well-defined heterointerfaces without safety concerns.

Worms in smallholder livestock systems: technologies and practices that make a difference.

Australian scientists, in partnership with Asian, African and Pacific nations have longstanding interests in applied research on helminth parasite control. Many technologies and practices have been successfully developed to control the parasite problems of smallholder and emerging farmers. This wide range extends from simple herbal remedies to complex, integrated use of chemicals, feeding and breeding. In many cases widespread adoption has been limited by lack of technical support, poor access to input markets and lack of incentives for poorer farmers to seek out and pay for innovations. A further new approach may be required that encompasses the wider production and market environment. The biological, social and economic context of each 'emerging farming system' is different and the matching of technologies to each system requires sound understanding of farmer needs and requirements. Thus, it is essential that farmers, extension workers, and scientists jointly decide what technologies to try, what results mean and, if successful, how to sustain their use. In one Asian example a range of technologies were considered for pig, large ruminant and goat production and parasite control through a participatory process which was also used to agree on what determines sustainability beyond testing. The criteria use to screen technologies and practices were (a) continued availability of inputs including dewormers, (b) dependence on related innovations (e.g. weaning or fencing) and (c) degree of community organisation required (e.g. control of breeding or communal grazing). On this basis deworming with chemicals, especially for Toxacara infection in cattle and buffalo calves following on from supplementary feeding with forages were the most feasible entry points. Further interventions were dependent on changes to the production system, including the introduction of weaning and controlled breeding. Further, the incentives for these production changes could not exist without improved market access and market signals for improved weight and condition. Examples such as this point to the need for stronger multidisciplinary and participatory approaches to parasite control.

OKT3 monoclonal antibody in cardiac transplantation. Experience with 102 patients.

OKT3 is a murine monoclonal antibody that is reactive against the CD3 surface antigen on T lymphocytes. This antigen appears to be essential for recognition of foreign antigen and for initiation of the process of cell-mediated rejection. One hundred and two patients having orthotopic cardiac transplantation in a single program during a 3-year period received prophylactic immune suppression with OKT3, along with azathioprine and low-dose steroids. Patients began receiving cyclosporine on Day 11; steroid-weaning was attempted 3 weeks after transplantation. In this group of patients, the time to the first rejection was 76 +/- 11 days (mean +/- SEM), and 85% were successfully weaned from maintenance steroids. Avoidance of the side effects of cyclosporine and/or high dose steroids during the perioperative period, combined with a long rejection-free interval and the likelihood of long-term maintenance free of steroids, make the use of OKT3 or similar agents an attractive alternative to conventional immunosuppression.