Visualizing the valence states of europium ions in Eu-doped BaAl2O4 using X-ray nanoprobe mapping.

This study develops and successfully demonstrates visualization methods for the characterization of europium (Eu)-doped BaAl2O4 phosphors using X-ray nanoprobe techniques. X-ray fluorescence (XRF) mapping not only gives information on the elemental distributions but also clearly reveals the valence state distributions of the Eu2+ and Eu3+ ions. The accuracy of the estimated valence state distributions was examined by performing X-ray absorption spectroscopy (XAS) across the Eu L3-edge (6.977 keV). The X-ray excited optical luminescence (XEOL) spectra exhibit different emission lines in the selected local areas. Their corresponding emission distributions can be obtained via XEOL mapping. The emission properties can be understood through correlation analysis. The results demonstrate that the main contribution to the luminescence intensity of the Eu-doped BaAl2O4 comes from the Eu2+ activator and the emission intensity will not be influenced by the concentration of Eu2+ or Eu3+ ions. It is anticipated that X-ray nanoprobes will open new avenues with significant characterization ability for unravelling the emission mechanisms of phosphor materials.

Effects of Variation in Al Content on the Emission of Eu Doped CaAlSiN3 Red Phosphor Synthesized by Combustion Synthesis Method for White LEDs.

Effects of Al content on the formation and the photoluminescence properties of CaAlSiN3:Eu2+ phosphor (CASIN) were investigated by a combustion synthesis method. XRD (X-ray diffraction), combined with PL (photoluminescence), TEM-EDS (transmission electron microscope equipped with an energy-dispersive X-ray spectroscope), and SAED (selected area electron diffraction) measurements, show that the bar-like CASIN gives a stronger emission than the plate-like and agglomerated fine particles. The emission intensity increases as the Al content increased from Al = 0.2 to Al = 0.8, which resulted from the extent of formation of CASIN increases. Then, the emission intensity decreases as the Al content is increased from Al = 0.8 to Al = 1.5, which resulted from the transformation of morphology of CASIN and a large amount formation of AlN. In addition, the extent of formation of CASIN increases with increasing Al from Al = 0.2 to Al = 1.2 and begins to decrease as Al is further increased to 1.5, and thus the peak emission wavelength increases from 647 nm to 658 nm as the Al molar ratio is increased from 0.2 to 1.2 and begins to decrease when further increasing the Al molar ratio to 1.5, which resulted from the large amount of AlN formed.

Effects of Ca Content on Formation and Photoluminescence Properties of CaAlSiN3:Eu2+ Phosphor by Combustion Synthesis.

Effects of Ca content (in the reactant mixture) on the formation and the photoluminescence properties of CaAlSiN3:Eu2+ phosphor (CASIN) were investigated by a combustion synthesis method. Ca, Al, Si, Eu2O3, NaN3, NH4Cl and Si3N4 powders were used as the starting materials and they were mixed and pressed into a compact which was then wrapped up with an igniting agent (i.e., Mg + Fe3O4). The compact was ignited by electrical heating under a N2 pressure of ≤1.0 MPa. By keeping the molar ratios of Al and Si (including the Si powder and the Si in Si3N4 powder) both at 1.00 and that of Eu2O3 at 0.02, XRD (X-ray diffraction) coupled with TEM-EDS (transmission electron microscope equipped with an energy-dispersive X-ray spectroscope) and SAED (selected area electron diffraction) measurements show that AlN:Eu2+ and Ca-α-SiAlON:Eu2+ are formed as the major phosphor products when the Ca molar ratio (denoted by Y) is equal to 0.25 and AlN:Eu2+ and Ca-α-SiAlON:Eu2+ could not be detected at Y ≥ 0.75 and ≥1.00, respectively. CASIN (i.e., CaAlSiN3:Eu2+) becomes the only phosphor product as Y is increased to 1.00 and higher. The extent of formation of CASIN increases with increasing Y up to 1.50 and begins to decrease as Y is further increased to 1.68. While the excitation wavelength regions are similar at various Y, the emission wavelength regions vary significantly as Y is increased from 0.25 to 1.00 due to different combinations of phosphor phases formed at different Y. The emission intensity of CASIN was found to vary with Y in a similar trend to its extent of formation. The Ca and Eu contents (expressed as molar ratios) in the synthesized products were found to increase roughly with increasing Y but were both lower than the respective Ca and Eu contents in the reactant mixtures.

Combustion Synthesis and Photoluminescence Properties of Red-Emitting CaAlSiN3:Eu2+ Phosphor for White-LEDs.

A combustion synthesis method has been developed for synthesis of Eu2+ doped CaAlSiN3 phosphor and its photoluminescence properties were investigated. Ca, Al, Si, and Eu2O3 powders were used as the Ca, Al, Si and Eu sources. The addition of NaN3, NH4Cl and Si3N4 powders was found to increase significantly the product yield. These powders were mixed and pressed into a compact, which was then wrapped up with an igniting agent (i.e., Mg+Fe3O4). The compact was ignited by electrical heating under a N2 pressure of ≤1.0 MPa. Effects of these experimental parameters on the product yield were investigated and a reaction mechanism was proposed. The synthesized CaAlSiN3:Eu2+ phosphor absorbs light in the region of 200-600 nm and shows a broad band emission in the region of 500-800 nm due to the 4f65d¹ → 4f7 transition of Eu2+. The sample doped with Eu2+ at the optimized molar ratio of 0.04 is efficiently excited by the blue light (460 nm) and generates emission peaking at ~650 nm with peak emission intensity ~106% of a commercially available phosphor, YAG:Ce3+(P46-Y3).The internal quantum efficiency of the synthesized phosphor was measured to be 71%, compared to 69% of the YAG:Ce3+ (P46-Y3).

Aripiprazole improves social interaction in Taiwanese children with pervasive developmental disorder.

Aripiprazole, an atypical antipsychotic, is effective in children with psychosis and few adverse effects have been reported. However, little is known about the efficacy and safety of aripiprazole in the treatment of autistic or other pervasive developmental disorders. We report three children with pervasive developmental disorders who were treated with aripiprazole for associated behavioral syndromes. Aripiprazole significantly improved the social interaction of all three children. Furthermore, two patients also showed significant improvement in depression/anxiety syndromes. The outcomes achieved with aripiprazole in these cases suggest that it is a potential therapeutic agent for children with pervasive developmental disorders.

Six cases of deletion 9p24 and trisomy 19q13.4 inherited from a familial balanced translocation.

The deletion 9p with trisomy 19q syndrome is a rare disorder. We report 2 adults and 4 children with deletion 9p and trisomy 19q due to familial balanced 9p;19q translocation with clinical features suggestive of monosomy 9p. The children had dysmorphic features and psychomotor retardation while the adults were self-sufficient but worked in a sheltered environment. High-resolution chromosome analysis and fluorescence in situ hybridization confirmed that the 6 cases of unbalanced translocation, der(9)t(9;19)(p24.1;q13.4) were inherited from a balanced translocation carrier, t(9;19)(p24.1;q13.4). The dysmorphic features included trigonocephaly, small nose with stunted tip, and long philtrum. Associated anomalies included wide-set nipples, extra finger flexion creases, hernia, external genitalia hypoplasia, scoliosis, and hypopigmented skin patch. We suggest that genetic counseling is necessary for those who have family members with dysmorphic features and/or major anomalies and/or psychomotor retardation.

Fluoxetine-induced memory impairment in four family members.

OBJECTIVE: Fluoxetine, a selective serotonin reuptake inhibitor antidepressant agent, has been implicated in learning and memory. Here, we report four cases from the same family of fluoxetine-related memory-impairment. RESULTS: Memory-impairment resulted after fluoxetine treatment and disappeared after changing to another selective serotonin reuptake inhibitor. CONCLUSIONS: There may be a relationship between fluoxetine-related memory impairment and genetic factors, and this side-effect appears to be specific to fluoxetine treatment. Possible mechanisms underlying this effect may be the drug's influence on the central serotonergic system or brain-derived neurotrophic factor.