The objective of this study was to evaluate the distribution of silver nanoparticles (NPs) in pregnant mice and their developing embryos. Silver NPs (average diameter 50 nm) were intravenously injected into pregnant CD-1 mice on gestation days (GDs) 7, 8, and 9 at dose levels of 0, 35, or 66 μg Ag/mouse. Mice were euthanised on GD10, and tissue samples were collected and analysed for silver content. Compared with control animals injected with citrate buffer vehicle, silver content was significantly increased (p < 0.05) in nearly all tissues from silver NP-treated mice. Silver accumulation was significantly higher in liver, spleen, lung, tail (injection site), visceral yolk sac, and endometrium compared with other organs from silver NP-treated mice. Furthermore, silver NPs were identified in vesicles in endodermal cells of the visceral yolk sac. In summary, the results demonstrated that silver NPs distributed to most maternal organs, extra-embryonic tissues, and embryos, but did not accumulate significantly in embryos.

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Lanthanum zirconate (LZO) formation and growth kinetics between 1273-1673 K at the A-site (La, Sr)-deficient Sr-doped lanthanum manganite (LSM)/yttrium-stabilized zirconia (YSZ) interface were studied using high-resolution transmission electron microscopy-energy-dispersive X-ray spectrometry (HRTEM-EDS). A cross-section TEM sample preparation technique was developed using a dual-beam focused ion beam and an in situ Omniprobe manipulator. The LZO pyrochlore phase was identified at the LSM/YSZ interface by TEM. The LZO is epitaxial with respect to the YSZ phase but not to the LSM phase. EDS results coupled with structural analysis suggest that La diffusion is a critical step in LZO formation. This study shows that LZO formation can occur even for A-sitedeficient LSM with a La composition of 78 mol% (o86 mol%). The activation energy for LZO formation was found to be 16878 KJ/mol. T. Gur-contributing editorThe authors would like to thank the United States Department of Energy for funding under project number DOE project DE-AC05-76RL01830 and Nextech for supplying cathode inks for use in this work.

Thin films of scandium oxide were epitaxially deposited on GaN via molecular beam epitaxy using elemental Sc and an oxygen plasma. After growth, the Sc2O3 films were annealed at a temperature of 800°C for 5min in the growth chamber. The structural quality of Sc2O3 films, before and after annealing, was characterized using high-resolution x-ray diffraction, atomic force microscopy (AFM), and high-resolution transmission electron microscopy (HRTEM). AFM of the films revealed smooth surfaces with 0.38nm root mean square roughness and show evidence of step-flow growth. The rocking curve and reflectivity scans of the films reveal that the Sc2O3∕GaN interface is abrupt and that it remains so after annealing. Pole figure and grazing incidence θ-2θ measurements show that the films are very textured along the c axis of the GaN substrate. HRTEM produced lattice images of the Sc2O3∕GaN interface illustrating the single crystal growth of the Sc2O3 films on the GaN.

The effect of uniaxial stress on solid phase epitaxy in patterned ͕001͖ Si wafers after ion implantation and annealing was investigated. It was found that mask edge defect formation was suppressed when tensile stresses greater than 100 MPa were applied along the ͗110͘ direction. The application of compressive stress retarded ͗001͘ regrowth up to ϳ6% and enhanced ͗110͘ regrowth up to ϳ6%, while tensile stress enhanced ͗001͘ regrowth up to ϳ60% and retarded ͗110͘ regrowth up to ϳ40%. A stress-dependent regrowth velocity model qualitatively agrees with the observed trends in the ratio of ͗001͘ and ͗110͘ regrowth velocities.

Few transmission electron microscopy ͑TEM͒ studies of single crystal diamond have been reported, most likely due to the time and difficulty involved in sample preparation. A method is described for creating a TEM cross section of single crystal diamond using a focused ion beam and in situ lift-out. The method results in samples approximately 10 m long by 3 m deep with an average thickness of 100-300 nm. The total time to prepare a cross-sectional TEM sample of diamond is less than 5 h. The method also allows for additional thinning to facilitate high resolution TEM imaging, and can be applied to oddly shaped diamond samples. This sample preparation technique has been applied to the study of ion implantation damage in single crystal diamond and its evolution upon annealing. High-pressure-high-temperature diamonds were implanted with Si + at an energy of 1 MeV and a temperature of 30°C. One sample, with a ͑110͒ surface, was implanted with a dose of 1 ϫ 10 14 Si cm −2 and annealed at 950°C for 10 and 40 min. No significant defect formation or evolution was discernible by cross-sectional transmission electron microscopy. Another sample, with a ͑100͒ orientation, was implanted with 1 MeV at 1 ϫ 10 15 Si cm −2 and annealed at 1050°C for 10 min. Prior to annealing, a heavily damaged but still crystalline region was observed. Upon annealing, the sample showed no signs of conversion either to an amorphous form of carbon or to graphite. This is unexpected as the energy and dose are above the previously reported graphitization threshold for diamond. Higher annealing temperatures and possibly a high vacuum will be required for future study of defect formation, evolution, and phase transformations in ion-implanted single crystal diamond.