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Downconversion (DC) with emission of two near-infrared photons about 1000 nm for each blue photon absorbed was obtained in thulium (Tm3+) and ytterbium (Yb3+) codoped yt-trium lithium fluoride (LiYF4) single crystals grown by an improved Bridgman method. The luminescent properties of the crystals were measured through photoluminescence excitation, emission spectra and decay curves. Luminescence between 960 and 1050 nm from Yb3+: 2F5/2 →2F7/2 transition, which was originated from the DC from Tm3+ ions to Yb3+ ions, was observed under the excitation of blue photon at 465 nm. Moreover, the energy transfer processes were studied based on the Inokuti-Hirayama model, and the results indicated that the energy transfer from Tm3+ to Yb3+ was an electric dipole-dipole interaction. The maximum quantum cutting efficiency approached up to 167.5% in LiYF4 single crystal codoped with 0.49mol% Tm3+ and 5.99mol% Yb3+. Application of this crystal has prospects for increasing the energy efficiency of crystalline Si solar cells by photon doubling of the high energy part of the solar spectrum. [ABSTRACT FROM AUTHOR]

Two new 2D metal–organic frameworks were assembled in different conditions. Single X-ray diffraction analyses reveal that complex 1possesses packing of large helical channels filled by guest water molecules; and 2has a 2-fold interpenetration layer-like structure with relatively petite helical channels, with guest water molecules residing in the void spaces between neighboring helical layers. The diverse structures may result from dissimilar crystal growth mechanisms with distinct thermal stable energies confirmed by theoretical calculation. Photoluminescent spectra, thermogravimetric analyses and power X-ray diffraction analyses were performed. [ABSTRACT FROM AUTHOR]

BACKGROUND: Angiogenesis appears to be an important event in the pathophysiology of endometriosis (EM) and adenomyosis. Two angiogenic factors, fibroblast growth factor (FGF) 1 and 2, play a central role in the initiation of angiogenesis. We investigated whether FGF1 -1385A/G and FGF2 754C/G polymorphisms are associated with a risk of developing EM and adenomyosis. METHODS: Genotypes were analyzed by the PCR-restriction fragment length polymorphism method in two groups of women, of Han ethnicity in north China, aged 16-55 years: (1) 421 EM patients and 421 controls; (2) 269 adenomyosis patients and 269 controls. RESULTS: There was no difference in genotype distribution of the FGF1 -1385A/G polymorphism between adenomyosis cases and controls (P > 0.05), but the frequency of the A allele in EM patients was lower than that in controls (P = 0.013). Genotype and allele frequencies of the FGF2 754C/C polymorphism were significantly different in both EM and adenomyosis cases versus control groups. Compared with C/C homozygotes, the G allele (C/G + G/G) was associated with a decreased susceptibility to developing EM [odds ratio (OR) = 0.575, 95% confidence interval (CI) = 0.387-0.854] and adenomyosis (OR = 0.577, 95% CI = 0.367-0.906). Combined genotype analysis of both polymorphisms also showed differences between cases versus controls (all P , 0.001). CONCLUSIONS: Our study shows for the first time that the FGF2 754C/G polymorphism may be associated with a risk of developing EM and adenomyosis in north Chinese women. Carriers of the G allele in the FGF2 gene appear to be protected from these gynecological diseases. Further studies in other populations, and of other candidate genes, are now warranted. [ABSTRACT FROM AUTHOR]