Optical Properties of GaSb Nanofibers

Amorphous GaSb nanofibers were obtained by ion beam irradiation of bulk GaSb single-crystal wafers, resulting in fibers with diameters of ~20 nm. The Raman spectra and photoluminescence (PL) of the ion irradiation-induced nanofibers before and after annealing were studied. Results show that the Raman intensity of the GaSb LO phonon mode decreased after ion beam irradiation as a result of the formation of the amorphous nanofibers. A new mode is observed at ~155 cm-1 both from the unannealed and annealed GaSb nanofiber samples related to the A1g mode of Sb–Sb bond vibration. Room temperature PL measurements of the annealed nanofibers present a wide feature band at ~1.4–1.6 eV. The room temperature PL properties of the irradiated samples presents a large blue shift compared to bulk GaSb. Annealed nanofibers and annealed nanofibers with Au nanodots present two different PL peaks (400 and 540 nm), both of which may originate from Ga or O vacancies in GaO. The enhanced PL and new band characteristics in nanostructured GaSb suggest that the nanostructured fibers may have unique applications in optoelectronic devices

Type 2 diabetes in pregnancy: Rates of fetal malformations and level of preconception care

International audienceAn observational study was performed to assess the prevalence of fetal malformations and the level of preconception care in women with Type 2 diabetes. Pregnant women with Type 2 diabetes who delivered between 2002 and 2010 were recruited to the study. The fetal malformation rate of patients with Type 2 diabetes was compared with the rate in a control group; the general population. The malformation rate was 3.2 (7.2-2.2%; p < 0.0001) greater in the diabetes group. In addition, only 4% of women with Type 2 diabetes had preconception care. Despite evidence of benefits in women receiving preconception care, patients with Type 2 diabetes do not attend for preconception counselling and the malformation rate is high

Liquide amniotique teinté ou méconial : doivent-ils modifier notre prise en charge obstétricale ?

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