Enhancing Bifunctional Electrocatalytic Activities of Oxygen Electrodes via Incorporating Highly Conductive Sm3+ and Nd3+ Double-Doped Ceria for Reversible Solid Oxide Cells.

Solid oxide cells (SOCs) are mutually convertible energy devices capable of generating electricity from chemical fuels including hydrogen in the fuel cell mode and producing green hydrogen using electricity from renewable but intermittent solar and wind resources in the electrolysis cell mode. An effective approach to enhance the performance of SOCs at reduced temperatures is by developing highly active oxygen electrodes for both oxygen reduction and oxygen evolution reactions. Herein, highly conductive Sm3+ and Nd3+ double-doped ceria (Sm0.075Nd0.075Ce0.85O2-δ, SNDC) is utilized as an active component for reversible SOC applications. We develop a novel La0.6Sr0.4Co0.2Fe0.8O3 -δ (LSCF)-SNDC composite oxygen electrode. Compared with the conventional LSCF-Gd-doped ceria oxygen electrode, the LSCF-SNDC exhibits ∼35% lower cathode polarization resistance (0.042 Ω cm2 at 750 °C) owing to rapid oxygen incorporation and surface diffusion kinetics. Furthermore, the SOC with the LSCF-SNDC oxygen electrode and the SNDC buffer layer yields a remarkable performance in both the fuel cell (1.54 W cm-2 at 750 °C) and electrolysis cell (1.37 A cm-2 at 750 °C) modes because the incorporation of SNDC promotes the surface diffusion kinetics at the oxygen electrode bulk and the activity of the triple phase boundary at the interface. These findings suggest that the highly conductive SNDC material effectively enhances both oxygen reduction and oxygen evolution reactions, thus serving as a promising material in reversible SOC applications at reduced temperatures.

Investigation of Ginsenosides and Antioxidant Activities in the Roots, Leaves, and Stems of Hydroponic-Cultured Ginseng (Panax ginseng Meyer).

There has been very little reported on ginsenoside composition and antioxidant activity of hydroponic-cultured ginseng roots (HCR), leaves (HCL), and stems (HCS). We profiled 6 ginsenoside compounds in HCR, HCL, and HCS using high-performance liquid chromatography. Antioxidative activity of HCR, HCL, and HCS were evaluated using total phenolic content (TPC) and total flavonoid content (TFC), 2,2-diphenyl-1-picrylhydrazyl (DPPH) free-radical-scavenging activity assays, and ferric reducing antioxidant power (FRAP) assays. Total ginsenoside contents of HCL and HCS were significantly higher than that of HCR (P<0.05). Rb1 was detected in HCR (23.02 mg/g) but was detected at very low levels in HCL and HCS (2.07~7.30 mg/g). Rg1 was the most abundant ingredient in HCL, followed by Rd; this was different than for HCR and HCS. The TPC and TFC ranged from 52.82~155.31 mg gallic acid equivalent/100 g and 194.71~256.52 mg quercetin equivalent/100 g, respectively, of which HCL contained the highest levels. Moreover, HCL was the most effective in both DPPH and FRAP activities. In this study, we also evaluated the inhibitory effect of HCR, HCL, and HCS on the activities of mushroom tyrosinase through whitening activity test. The inhibitory effect of HCL on tyrosinase activity was higher than that of HCR and HCS. This study provides information about ginsenoside contents and the antioxidative activity of hydroponic-cultured ginseng, and suggests that the whole ginseng plant (including roots, leaves, and stems) may be a beneficial functional vegetables.

Correlation of Time-Dependent Oxygen Surface Exchange Kinetics with Surface Chemistry of La0.6Sr0.4Co0.2Fe0.8O3-δ Catalysts.

The Sr segregation at the surface of a perovskite La0.6Sr0.4Co0.2Fe0.8O3-δ (LSCF) oxygen electrode is detrimental to the electrochemical performance and durability of energy conversion devices such as solid oxide fuel cells. However, a quantitative correlation of degradation of the oxygen surface exchange kinetics with Sr precipitation formation at the LSCF surface is not clearly understood yet. Herein, the correlation of the time-dependent degradation mechanisms of the LSCF catalysts with respect to Sr segregation phenomenon at the surface were investigated at 800 °C for a prolonged annealing time (∼800 h) by combining in situ electrochemical measurements, and ex situ chemical and structural analyses at the multiscale. The in situ monitored surface exchange coefficient (kchem) was found to drastically drop by ∼86% over the 800 h, and it was accompanied by the formation of Sr-containing secondary phases on the bulk LSCF surface, as expected. However, the estimated coverage of Sr segregation on the LSCF surface was only ∼15%, even after 800 h of aging time, showing significant deviation from the kchem degradation rate (∼86%). The surface chemistry evolution at the clean surface area, which is believed to be electrochemically active, was further analyzed on the nanoscale. The quantified results showed that the Sr elemental fraction of the A-site at the outermost surface of the LSCF samples was becoming deficient from ∼4.0 at 0 h to ∼0.27 at 800 h annealing. Interestingly, the time-dependent behavioral tendencies between kchem degradation and surface Sr fractional changes were highly analogous. Thus, our results suggest that this Sr deficiency at the clean surface region more dominantly impacts the degradation process rather than an electrochemical activity passivation by the SrOx precipitates, which has been shown to be a major degradation mechanism of LSCF performance.

Functionally Graded Bismuth Oxide/Zirconia Bilayer Electrolytes for High-Performance Intermediate-Temperature Solid Oxide Fuel Cells (IT-SOFCs).

A functionally graded Bi1.6Er0.4O3 (ESB)/Y0.16Zr0.84O1.92 (YSZ) bilayer electrolyte is successfully developed via a cost-effective screen printing process using nanoscale ESB powders on the tape-cast NiO-YSZ anode support. Because of the highly enhanced oxygen incorporation process at the cathode/electrolyte interface, a novel bilayer solid oxide fuel cell (SOFC) yields extremely high power density of ∼2.1 W cm-2 at 700 °C, which is a 2.4 times increase compared to that of the YSZ single electrolyte SOFC.

Comparative in vitro release and clinical pharmacokinetics of leuprolide from Luphere 3M Depot, a 3-month release formulation of leuprolide acetate.

A 3-month depot formulation of leuprolide acetate (Luphere 3M Depot) with a mean microsphere diameter of 22.3 µm was prepared aseptically by spray-drying glacial acetic acid solution of the drug and polylactic acid, and lyophilization in a d-mannitol solution. The encapsulation efficiency and loading content of the drug in the Luphere 3M Depot were 94.7% and 9.92% (w/w), respectively. The in vitro release of leuprolide from the depot was substantially delayed and the release profile was similar to that of Lucrin Depot (Abbott Korea, Korea). The safety and pharmacokinetics of leuprolide were investigated over a period of 42 days in 20 prostate cancer patients following a subcutaneous injection of Luphere 3M or Lucrin Depot suspensions (leuprolide acetate dose of 11.25 mg) in a multi-center, randomized, single dose, parallel study. Both formulations were well tolerated by the patients and no serious adverse effects were observed during and after the study. No significant differences were observed in the maximum serum concentration (Cmax) and area under the curve (AUClast) of leuprolide between the two formulations. The results suggest comparable safety and efficacy profiles of Luphere 3M Depot and Lucrin Depot in clinical situations.

Analysis of acamprosate in beagle dog plasma by LC-MS-MS.

A rapid, sensitive, and specific analytical method was developed and validated to quantify acamprosate calcium in beagle dog plasma. The method employs a single plasma protein precipitation, and the analytes are separated by chromatography on an Acquity UPLC HSS T3 column and analyzed by mass spectrometry in the multiple reaction monitoring (MRM) mode. The method has a chromatographic run time of 1.25 min and a linear calibration curve over the range 200-10000 ng/mL (r(2)>0.9994). The intra-day and inter-day accuracy and precision were within 10.0% for the analyte. Acamprosate was stable during all sample storage, preparation, and analytical periods. This method was employed in a pharmacokinetic study of an acamprosate 333 mg enteric-coated tablet in 8 male beagle dogs that received single 666 mg doses (333 mg x 2 tablets). The proposed method enables identification and quantification in pharmacokinetic studies of acamprosate in beagle dog plasma.

Development of a music group psychotherapy intervention for the primary prevention of adjustment difficulties in Korean adolescent girls.

PROBLEM: Traditionally, adolescent mental health in Korea has not been a prime focus for educators, health workers, and politicians, yet a majority of sampled adolescents report interpersonal sensitivity (Kim, 2003). METHOD: Thirty-five adolescent girls took part in a six-session school-based music group psychotherapy pilot intervention designed to promote relationships and improve self-control skills. FINDING: Participants identified several outcome benefits that may serve as protective factors in their continued social and emotional development. CONCLUSIONS: Music is a medium that promotes interpersonal relatedness among Korean adolescent girls. More research is necessary to identify long-term benefits of preventive music group psychotherapy interventions among the adolescent population.