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We investigated high-pressure induced phase transitions in Y 2 O 3 and Eu-doped Y 2 O 3 ͑Y 2 O:Eu 3+ ͒ using angular dispersive synchrotron x-ray diffraction, Raman spectroscopy, and photoluminescence ͑PL͒. With increasing pressure, we observed a series of phase transformations in Y 2 O 3 :Eu 3+ , which followed a structure sequence of cubic→ monoclinic→ hexagonal, while Y 2 O 3 followed a sequence of cubic→ hexagonal. During decompression, both hexagonal structured Y 2 O 3 and Y 2 O 3 :Eu 3+ transformed into monoclinic phases which were quenchable back to ambient pressure. Raman and PL measurements shed additional light on the different phase transition behavior in these two samples.

Red phosphors BaTiF6:Mn(4+) with microrod and polyhedron morphologies have been prepared respectively by etching TiO2 and Ti(OC4H9)4 in a HF solution with an optimized concentration of KMnO4 at 1.5 mmol L(-1) in hydrothermal conditions. The red phosphor BaTiF6:Mn(4+) exhibits a broad excitation band in the blue region and sharp emission peaks in the red region. A white LED (WLED) fabricated with the red phosphor BaTiF6:Mn(4+) shows "warm" white light that possesses a color rendering index of 93.13 at a color temperature of 4073.1 K.

Near-infrared (NIR) quantum cutting (QC) involving the emission of two NIR photons per absorbed photon via a cooperative downconversion mechanism in one-dimensional (1D) (YbxGd1−x)Al3(BO3)4:Tb3+ nanorods has been demonstrated. The authors have analyzed the measured luminescence spectra and decay lifetimes and proposed a mechanism to rationalize the QC effect. Upon excitation of Tb3+ with a blue-visible photon at 485nm, two NIR photons could be emitted by Yb3+ through an efficient cooperative energy transfer from Tb3+ to two Yb3+ with optimal quantum efficiency as great as 196%. The development of 1D Tb3+–Yb3+ QC nanomaterials could open up a possibility to realize high efficiency silicon-based solar cells by means of downconversion of the green-to-ultraviolet part of the solar spectrum to ∼1000nm photons with a twofold increase in the photon number.

The nature of intestinal absorption of most herbal medicine is unknown. Cryptotanshinone (CTS) is the principal active constituent of the widely used cardiovascular herb Salvia miltiorrhiza (Danshen). We investigated the oral bioavailability of CTS in rats and the mechanism for its intestinal absorption using several in vitro and in vivo models: 1) Caco-2 cell monolayers; 2) monolayers of MDCKII cells overexpressing P-glycoprotein (PgP); and 3) single-pass rat intestinal perfusion with mesenteric vein cannulation. The systemic bioavailabilities of CTS after oral and intraperitoneal administration at 100 mg/kg were 2.05 and 10.60%, respectively. In the perfused rat intestinal model, permeability coefficients based on CTS disappearance from the luminal perfusate (P lumen ) were 6.7-to 10.3-fold higher than permeability coefficients based on drug appearance in venous blood (P blood ). P blood significantly increased in the presence of the P-gP inhibitor, verapamil. CTS transport across Caco-2 monolayers was pH-, temperature-and ATP-dependent. The transport from the apical (AP) to the basolateral (BL) side was 3-to 9-fold lower than that from the BL to the AP side. Inclusion of verapamil (50 M) in both AP and BL sides abolished the polarized CTS transport across Caco-2 cells. Moreover, CTS was significantly more permeable in the BL to AP than in the AP to BL direction in MDCKII and MDR1-MDCKII cells. The permeability coefficients in the BL to AP direction were significantly higher in MDCKII cells overexpressing PgP. These findings indicate that CTS is a substrate for PgP that can pump CTS into the luminal side.

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