Aims/hypothesis Excess glucose transport to embryos during diabetic pregnancy causes congenital malformations. The early postimplantation embryo expresses the gene encoding the high-K m GLUT2 (also known as SLC2A2) glucose transporter. The hypothesis tested here is that high-K m glucose transport by GLUT2 causes malformations resulting from maternal hyperglycaemia during diabetic pregnancy. Materials and methods Glut2 mRNA was assayed by RT-PCR. The K m of embryo glucose transport was determined by measuring 0.5-20 mmol/l 2-deoxy[ 3 H]glucose transport. To test whether the GLUT2 transporter is required for neural tube defects resulting from maternal hyperglycaemia, Glut2 +/− mice were crossed and transient hyperglycaemia was induced by glucose injection on day 7.5 of pregnancy. Embryos were recovered on day 10.5, and the incidence of neural tube defects in wild-type, Glut2 +/− and Glut2 −/− embryos was scored. Results Early postimplantation embryos expressed Glut2, and expression was unaffected by maternal diabetes. Moreover, glucose transport by these embryos showed Michaelis-Menten kinetics of 16.19 mmol/l, consistent with transport mediated by GLUT2. In pregnancies made hyperglycaemic on day 7.5, neural tube defects were significantly increased in wild-type embryos, but Glut2 +/− embryos were partially protected from neural tube defects, and Glut2 −/− embryos were completely protected from these defects. The frequency of occurrence of wild-type, Glut2 +/− and Glut2 −/− embryos suggests that the presence of Glut2 alleles confers a survival advantage in embryos before day 10.5. Conclusions/interpretations High-K m glucose transport by the GLUT2 glucose transporter during organogenesis is responsible for the embryopathic effects of maternal diabetes.

Efficient energy transfer from Si-nanoclusters to Er ions in silica induced by substrate heating during deposition J. Appl. Phys. 108, 064302 (2010); 10.1063/1.3481375 Energy transfer and 1.54 μ m emission in amorphous silicon nitride films Appl. Phys. Lett. 95, 031107 (2009); Influence of the silicon nanocrystal size on the 1.54 μ m luminescence of Er-doped SiO / SiO 2 multilayers

Ultrafast two-color pump-probe measurements, time-resolved photoluminescence (TRPL), and photoluminescence excitation measurements were performed on Si-rich nitride (SRN) and Er doped SRN (Er:SRN) nanocrystals samples. Transient absorption data were compared with picosecond TRPL and excited state absorption cross (ESA) sections σ were measured at different wavelengths. Our data show that σ in Er:SRN, which is approximately 10−19cm2 at 1.54μm, does not scale with the ∼λ2 behavior predicted by simple free carrier absorption models. Finally, our data demonstrate that in Er:SRN efficient energy transfer to Er ions occurs on the nanosecond time scale with reduced ESA compared to Er-doped oxide-based systems.

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Two-dimensional arrays of silver nanocylinders fabricated by electron-beam lithography are used to demonstrate plasmon-enhanced near-green light emission from nitride semiconductor quantum wells. Large enhancements in peak photoluminescence intensity (up to a factor of over 3) are obtained, accompanied by a substantial reduction in recombination lifetime indicative of increased internal quantum efficiency. The measured enhancement factors exhibit a strong dependence on the nanoparticle dimensions, underscoring the importance of geometrical tuning for this application.