TEM and HREM of diamond crystals grown on Si tips: structure and results of ion-beam-treatment.

Diamond single crystals were grown on the silicon whiskers by a hot filament chemical vapor deposition technique at the filament temperature about 2100 degrees C and the temperature of support 800 degrees C. Specimens were examined by SEM, TEM, HRTEM and SAED. When the filament temperature was about 1900 degrees C globular polycrystalline diamond particles were grown. At a support temperature more then 800 degrees C SiC nanoparticles were formed. To investigate the ion etching process of the silicon tip/diamond system, tips were treated with an Ar(+) beam with energy up to 30 kV. The results depend on fluence: at 4 x 10(18)ion/cm(2) diamonds and partially Si tips were destroyed, amorphous layer was formed (sometimes with nanometric size fragments of diamond); at 1 x 10(18)ion/cm(2) sharpened diamonds (radius of curvature about 20 nm) covered with amorphous layer (radius about 80 nm) probably with nanoclusters of diamond were observed; at 4.4 x 10(17) ion/cm(2) there was no visible tip sharpening but formation of amorphous thick layer occurred. The emission characteristics of Si tips covered with diamond were improved due to ion treatment. Since such tips in our case were covered with amorphous layer containing nanometric size fragments of diamond, we suppose this layer is responsible for electron emission improvement.

Ethylene signaling: from mutants to molecules.

The past decade has been incredibly productive for ethylene researchers. Major components in the ethylene signaling pathway in plants have been identified and characterized. The past year's contributions include the crystallographic analysis of the Arabidopsis ETR1 receiver domain, antisense studies of the tomato ethylene receptor genes LeETR4 and NR, and the cloning and functional characterization of several Arabidopsis EREBP-related transcription activators and repressors, and of an EIN3-ortholog of tobacco. Additional evidence for the interconnection of the ethylene and auxin responses was provided by the cloning and characterization of Arabidopsis NPH4. Finally, the first discovery of ethylene responsiveness in an animal species implied a more universal role for ethylene than previously thought.

[Seasonal variability in the insecticide resistance and irritability of Anopheles superpictus]. / Sezonnaia izmenchivost' rezistentnosti i razdrazhimosti k insektitsidam u Anopheles superpictus.

The resistance and irritability to malathion, fenitrothion, propoxur and DDT (WHO insecticide impregnated papers) in Anopheles superpictus from Dangara District were determined three times in season. Complete susceptibility to malathion, fenitrothion and DDT and low resistance to propoxur probably based on knockdown mechanism were noticed. DDT and malathion irritability levels were high, and those for fenitrothion and propoxur were lower. During the season irritability to malathion and fenitrothion (organophosphorous compounds) was slightly decreasing, and in contrast was increasing to propoxur (carbamate). Irritability to DDT (organochloride) considerably fell down in August and achieved the initial level in September again. None of the tested insecticides can be recommended for residual spraying in Dangara District because of high irritability levels in mosquitos or danger of its rapid increase after onset of spraying.

[Trials of the insecticides Icon and Ficam against mosquitoes in the southern USSR]. / Ispytaniia insektitsidov aikona i fikama protiv komarov na iuge SSSR.

Two residual insecticides (Icon 10% WP, ICI and Ficam W 80% WP, CAMCO) were in 1989 tested in field trials in Tajikistan, Azerbaijan and Uzbekistan against Anopheles superpictus, An. sacharovi, An. pulcherrimus, An. martinius, Culex pipiens, Aedes caspius, and Ae. vexans. In dosages recommended by the producing companies (0.025 g/m2 a. i. for Icon and 0.4 g/m2 for Ficam), the above preparations showed residual action during 2-3 months. Icon and Ficam did not cause irritability and repellency in mosquito, which did not migrate to unsprayed rooms of cattle sheds. In areas where the experimental trials were large-scale, a stable decrease in mosquito density was achieved. An insecticide action of ICON was also noted on house flies, cockroaches, bed bugs, fleas and spiders.