Solid solubility of rare earth elements (Nd, Eu, Tb) in In2-xSnxO3 - effect on electrical conductivity and optical properties.

Wide band-gap semiconductors doped with luminescent rare earth elements (REEs) have attracted recent interest due to their unique optical properties. Here we report on the synthesis of the transparent conducting oxides (TCOs) indium oxide and indium tin oxide (ITO) doped with neodymium, europium and terbium. The solid solubility in the systems was investigated and isothermal phase diagrams at 1400 °C were proposed. The solubility of the REEs in In2O3 is mainly determined by the size of the rare earth dopant, while in ITO the solid solubility was reduced due to a strong tendency of the tin and REE co-dopants to form a pyrochlore phase. The effect of the REE-doping on the conductivity of the host was determined and optical activity of the REE dopants were investigated in selected host materials. The conductivity of sintered materials of REE-doped In2O3 was significantly reduced, even at small doping concentrations, due to a decrease in carrier mobility. The same decrease in mobility was not observed in thin films of the material processed at lower temperatures. Strong emissions at around 611 nm were observed for Eu-doped In2O3, demonstrating the possibility of obtaining photoluminescence in a TCO host, while no emissions was observed for Nd- and Tb-doping.

Visual results of progressive multifocal posterior chamber intraocular lens implantation.

PURPOSE: To evaluate corrected and uncorrected near, intermediate, and distance visual acuities in eyes with a progressive multifocal intraocular lens (IOL) and to determine the effect of the lens on contrast sensitivity. SETTING: Multicenter study. METHODS: This prospective study comprised 59 eyes that had uneventful cataract surgery and implantation of a progressive multifocal IOL at three study centers. Uncorrected and corrected near, intermediate, and distance visual acuities were measured, as was contrast sensitivity at different frequencies. One year results are reported. Patient satisfaction was assessed using a subjective questionnaire. RESULTS: Distance visual acuity improved from 0.13 Snellen lines uncorrected and 0.23 with best correction preoperatively to 0.77 and 0.96 lines, respectively, postoperatively. Uncorrected preoperative near acuity was 13.28 Jaeger lines and best corrected acuity, 8.93 lines. These improved to 4.75 and 2.69 lines, respectively. The differences between visual acuity at intermediate distances and best distance and near acuities were not significant. Patient satisfaction was highest with vision under good light conditions and when viewing larger objects. CONCLUSION: Visual performance with the multifocal progressive IOL was adequate at various distances without additional correction. It was less satisfactory under poor light conditions.

Particle-induced X-ray emission (PIXE) for detection of lead in mouse blastocysts.

Mice were injected intravenously with lead chloride, 75 micrograms/g body weight. The mice were in an experimental delay of implantation, which offered the functionally steady conditions required for developing the testing procedures. One day after the administration of lead, blastocysts were flushed from the uterine cavity, placed on thin foils of Kapton, and air-dried. The dried blastocysts were analyzed in a nuclear microprobe with a particle intensity of 10 nanoampere (nA) for 300 s using a spatial resolution of 3 microns. The average lead concentration of blastocysts at implantation was 3.90 micrograms/g dry weight. We judge this technique to be useful for evaluating the transport of heavy metals from mother to preembryos, not only under the present experimental conditions but also in normal pregnancies and in other species.