Growth and Electrical Properties of PbMg0.047Nb0.095Zr0.416Ti0.442O3 Films Fabricated by Metalorganic Decomposition

On the basis of experimental data on the piezoelectric pinpoint composition of ceramics of the ternary system Pb(Mg1/3Nb2/3)O3-PbZrO3-PbTiO3 (PMNZT), which we investigated in our previous report, epitaxial PbMg0.047Nb0.095Zr0.416Ti0.442O3 thick films with thicknesses ranging from 0.4 to 1.9 m were fabricated on Pt(100)/MgO(100) substrates by metalorganic decomposition. The film- thickness dependence on the structural and electrical properties (dielectric, piezoelectric and ferroelectric properties) was investigated. All PMNZT films exhibited a highly uniform (001) orientation, regardless of the film thickness. The cross-sectional transmission electron microscope micrographs and all the physical data suggest that high-density PMNZT thick films with a thickness  1.0 m can be expected to function as highly electrically insulating capacitors with high potential for piezo- and ferroelectric applications.

Marine fungi from Seychelles. III. Aniptodera mangrovii sp.nov. from mangrove wood

Collections of higher marine fungi in Seychelles included an undescribed species of Aniptodera: A. mangrovii Hyde sp.nov. from driftwood and dead mangrove wood. This species differs from A. chesapeakensis in the size of the ascospores and in ascospore appendage morphology. Aniptodera mangrovii is described and illustrated by light microscope and scanning and transmission electron microscope micrographs.

Capture of nematodes by Arthrobotrys oligospora, an electron microscope study

The capture of nematodes by Arthrobotrys oligospora consists of (1) firm adhesion of the nematode to the capture organ, (2) penetration of the nematode cuticle by a penetration hypha, and (3) digestion of the nematode. Penetration of the nematode cuticle by a penetration hypha originating from the trap took place within 1 h after addition of nematodes to a fungal culture and occurred at any point on the nematode surface. Vegetative hyphae were able to invade an immobilized nematode only through the body orifices (8–12 h after addition of nematodes to fungal cultures lacking traps). The presence of prey caused an increased secretion of adhesive from the trap. Scanning electron microscope micrographs show a captured nematode covered by a mucilaginous coat. In transmission electron microscope micrographs of thin sections, a distinct osmiophilic layer between trap and nematode is always present. Since penetration occurred at the point of deposit of these substances, it is suggested that the osmiophilic layer also has enzymatic activity. An osmiophilic layer was never seen around vegetative hyphae, indicating the lack of both adhesive and similar enzymes.The traps contained numerous membranous electron-dense vesicles (150–300 nm) not present in hyphae. Large osmiophilic inclusions (1–2 μm) were more common in traps at certain stages of development than in hyphae. The results indicate that the adhesive and the digestive enzymes originate from either or both of these organelles.