Photoluminescence properties of a new orange-red-emitting Sm(3+)-La3SbO7 phosphor.

The antimonate compound La3SbO7 has high chemical stability, lattice stiffness and thermal stability. Orange-red-emitting antimonate-based phosphors La3SbO7:xSm(3+) (x = 0.02, 0.05, 0.08, 0.10, 0.15, 0.20 and 0.25) were synthesized. The phase structure and photoluminescence properties of these phosphors were investigated. The emission spectrum obtained on excitation at 407 nm contained exclusively the characteristic emissions of Sm(3+) at 568, 608, 654 and 716 nm, which correspond to the transitions from (4)G5/2 to (6)H5/2, (6)H7/2, (6)H9/2 and (6)H11/2 of Sm(3+), respectively. The strongest emission was located at 608 nm due to the (4)G5/2→(6)H7/2 transition of Sm(3+), generating bright orange-red light. The critical quenching concentration of Sm(3+) in La3SbO7:Sm(3+) phosphor was determined as 10% and the energy transfer between Sm(3+) was found to be through an exchange interaction. The International Commission on Illumination chromaticity coordinates of the La3SbO7:0.10Sm(3+) phosphors are located in the orange-red region. The La3SbO7:Sm(3+) phosphors may be potentially used as red phosphors for white light-emitting diodes.

Characterization of resting-state fMRI-derived functional connectivity in patients with deficiency versus excess patterns of major depression.

OBJECTIVE: Patients with major depression (MD) experience a variety of emotional and mental problems accompanied by characteristic clinical symptoms. Based on traditional Chinese medicine (TCM) notions, the clinical appearance of MD can be divided into two syndromes, namely a deficiency pattern (DP) and an excess pattern (EP), depending on the patient's clinical symptoms, pulse, and lingual signs. Brain functional neuroimaging has demonstrated cerebral activity abnormalities in MD patients. However, such abnormalities have not been linked to particular symptoms of MD. The objective of this work was to compare functional connectivity of the posterior cingulate cortex (PCC) across MD patients with DP, MD patients with EP, and normal control (NC) subjects in a resting-state functional magnetic resonance imaging (rs-fMRI) study. METHODS: Participants (24 DP patients, 21 EP patients, and 20 NCs) underwent rs-fMRI scans. Whole-brain functional connectivity of a seed in the PCC was then mapped for each subject. Functional connectivity differences among the three studied groups were analyzed statistically. RESULTS: Compared to the NC group, DP patients had decreased functional connectivity of the PCC with the right middle temporal gyrus and bilateral precuneus, as well as increased functional connectivity of the PCC with the bilateral middle frontal gyrus. Meanwhile, compared to the NC group, the EP group had decreased functional connectivity of the PCC with both the middle temporal gyrus and bilateral precuneus, as well as increased functional connectivity of the PCC with the bilateral superior frontal gyrus. Relative to the DP group, the EP group had reduced functional connectivity of the PCC with the bilateral cerebellum and left superior frontal gyrus. CONCLUSION: Functional connectivity changes differ between MD patients with different TCM syndrome types, suggesting that the TCM clinical syndromes of MD are associated with correlates in cerebral functional activity.