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The production of white light based on a near-UV LED chip requires incorporating three inorganic phosphors that emit in the blue, green, and red portions of the visible spectrum. Using a near-UV LED has the advantage of generating a light with excellent color quality, but due to the large Stokes' shift between the LED excitation and the multiple phosphor emissions, these devices can suffer from a low overall efficiency. To minimize this inherent energy loss, the three phosphors employed to convert the LED emission must be very efficient, as measured by the internal photoluminescent quantum yield (Φ). In this work, we report the synthesis of a cubic borate, Ba3Y2B6O15, which when substituted with Ce3+ becomes an efficient blue phosphor. This compound can be prepared using a multistep high temperature solid state synthesis with the ensuing photoluminescent measurements revealing a broad excitation band (300-415 nm) making this phosphor compatible with a 365 or 400 nm LED chip. Ba3Y2B6O15:Ce3+ luminesces bright blue (λem = 446 nm) and is the narrowest Ce3+ based phosphor reported thus far with a full width at half the maximum of only 70 nm due to its highly symmetric, nearly perfect octahedral rare-earth coordination environment. Moreover, exciting Ba3Y2B6O15:Ce3+ at 365 nm results in a Φ of 84% owing to the dense connectivity of the crystal structure. This combination of a broad excitation spectrum, narrow emission, and high Φ suggest that Ba3Y2B6O15:Ce3+ is an excellent phosphor for incorporation in a three-phosphor, near-UV LED system. Furthermore, these results demonstrate that a highly symmetric and ordered rare-earth environment in combination with a highly connected polyhedral network is a universal design criterion to generate narrow-emitting phosphors. [ABSTRACT FROM AUTHOR]

This study focused on the solubility enhancement and thein vivoantidotal efficacy testing of a new potential cyanide (CN) countermeasure, dimethyl trisulfide (DMTS). Various FDA approved cyclodextrins (HPβCD, RMβCD, HPγCD), cosolvents (ethanol, polyethylene glycols, propylene glycol), surfactants (cremophor EL, cremophor RH 40, sodium cholate, sodium deoxycholate, polysorbate 80) and their combinations were applied. Based on the solubility enhancing potential of the tested systems, polysorbate 80 was chosen for furtherin vivoefficacy studies. A composition comprising 15% polysorbate 80 and 50 mg/ml DMTS with the applied DMTS dose of 100 mg/kg provided a therapeutic antidotal protection of 3.4 × LD50. For comparison, the present therapy of sodium thiosulfate (TS) with the dose of 100 mg/kg provided only 1.1 × LD50protection, and at the dose of 200 mg/kg, the LD50was enhanced by 1.3 times. No difference in the therapeutic protection by DMTS was detected when the concentration of polysorbate 80 was increased to 20% (3.2 × LD50protection). These data demonstrate the potential importance of DMTS as a CN countermeasure, and the formulation comprising polysorbate 80 provides the base of an injectable intramuscular dosage form that can later serve as a CN antidotal kit suitable for mass scenario. [ABSTRACT FROM AUTHOR]

Following an investigation proving La 2 Si 4 N 6 C crystallizes in a monoclinic space group, isostructural to Y 2 Si 4 N 6 C, the reportedly hexagonal (La 0.5 Y 0.5 ) 2 Si 4 N 6 C was reinvestigated to examine the apparent crystal structure change across the solid solution. Initially, calculating the electronic structure and phonon density of states of (La 0.5 Y 0.5 ) 2 Si 4 N 6 C in the P6 3 mc space group revealed an imaginary phonon mode, which is indicative of a structural instability. Displacing the atoms along the pathway of the imaginary vibration led to a previously unreported space group for carbonitridosilicates, trigonal P31c. The assignment of the trigonal space group was subsequently confirmed by synthesizing (La 0.5 Y 0.5 ) 2 Si 4 N 6 C using high-temperature, solid state synthesis and analyzing the crystal structure with high-resolution synchrotron X-ray powder diffraction. Preparing the solid solution, (La δ Y 1-δ ) 1.98 Ce 0.02 Si 4 N 6 C (δ = 0-0.5), showed that the crystal structure changes from the monoclinic to the trigonal space group at δ ≈ 0.25. Finally, substituting Ce 3+ in the crystal structure to investigate the optical response via steady-state luminescent and photoluminescent quantum yield measurements reveals severe luminescent quenching with increasing La 3+ content, due to a combination of absorption of luminescence by the host structure and thermal quenching. These results display the virtue of combining computational and experimental techniques to solve inorganic crystal structures and assess potential phosphor hosts.