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Abstract: A composite of SrTiO3/TiO2 was successfully prepared using TiO2 (Degussa P25) and SrTiO3 powders as starting materials. The composite was characterized by X-ray diffraction (XRD), UV–vis absorption spectrum, scanning electron microscope (SEM), and surface photovoltage spectroscopy (SPS). The SrTiO3/TiO2 composite presents an enhanced photovoltaic response compared with pure TiO2 and SrTiO3. The enhancement was explained by investigating the energy levels of TiO2 and SrTiO3, and the photoluminescence (PL) spectra of TiO2, SrTiO3 and SrTiO3/TiO2. The analysis of energy levels shows that those of TiO2 and SrTiO3 are matching, which improves the separation efficiency of photogenerated carriers. The PL spectra indicate that the formation of SrTiO3/TiO2 composite decreases the recombination rate of photogenerated carriers. Thus the photovoltaic response enhancement is mainly resulting from the improved separation efficiency and decreased recombination rate of photogenerated carriers for SrTiO3/TiO2 composite. [Copyright &y& Elsevier]

For biomonitoring environmental exposure to acrylonitrile (AN), a monoclonal antibody (mAb) A2D1, was developed to recognize specifically the hemoglobin (Hb) adduct, Hb-AN, but not Hb itself. This appears to be the first example that a small molecule-like AN may introduce new antigenicity into hemoglobin, which already exhibits multiple antigenic determinants. This report addresses the localization of the newly formed antigenic sites in human Hb-AN. As antigenic probes, the AN conjugates of 10 amino acids, six dipeptides, and four tripeptides were prepared as monitored by 1H NMR, and their antigenicity was evaluated by competitive inhibition immunoassay. A Lys- ℇNH-AN was found essential to inhibiting activity. The potent peptide-AN inhibitors, containing a sequence of His and Lys, showed IC50 at the micromolar concentration, thus implicating human Hb α-89,90 and Hb β-143,144 in the distal heme pocket region as the new antigenic sites. [ABSTRACT FROM AUTHOR]

Abstract: Rearing in darkness slows the time course of the visual cortical critical period, such that at 5 weeks of age normal cats are more plastic than dark-reared cats, while at 20 weeks dark-reared cats are more plastic [Mower GD (1991) The effect of dark rearing on the time course of the critical period in cat visual cortex. Dev Brain Res 58:151–158]. Thus, genes that are important for visual cortical plasticity should show differences in expression between normal and dark-reared visual cortex that are of opposite direction in young versus older animals. Previously, we showed by differential display polymerase chain reaction and northern blotting that mRNA for Munc13–3, a mammalian homologue of the C. elegans uncoordinated (unc) gene, shows such bidirectional regulation in cat visual cortex [Yang CB, Zheng YT, Li GY, Mower GD (2002) Identification of Munc13–3 as a candidate gene for critical period neuroplasticity in visual cortex. J Neurosci 22:8614–8618]. Here, the analysis is extended to Munc13–3 protein in mouse visual cortex, which will provide the basis for gene manipulation analysis. In mice, Munc13–3 protein was elevated 2.3-fold in dark-reared compared with normal visual cortex at 3.5 weeks and 2.0-fold in normal compared with dark-reared visual cortex at 9.5 weeks. Analysis of variance of protein levels showed a significant interaction, indicating that the effect of dark rearing depended on age. This bidirectional regulation was restricted to visual cortex and did not occur in frontal cortex. Bidirectional regulation was also specific to Munc13–3 and was not found for other Munc13 family members. Munc13 proteins serve a central priming function in synaptic vesicle exocytosis at glutamatergic and GABAergic synapses and this work contributes to the growing evidence indicating a role of Munc13 genes in synaptic plasticity. [Copyright &y& Elsevier]