A precise control of the size, density, and distribution of metal nanoparticles dispersed on functional oxide supports is critical for promoting catalytic activity and stability in renewable energy and catalysis devices. Here, we measure the growth kinetics of individual Co particles ex-solved on SrTi0.75Co0.25O3‑δ polycrystalline thin films under a high vacuum, and at various temperatures and grain sizes using in situ transmission electron microscopy. The ex-solution preferentially occurs at grain boundaries and corners which appear essential for controlling particle density and distribution, and enabling low temperature ex-solution. The particle reaches a saturated size after a few minutes, and the size depends on temperature. Quantitative measurements with a kinetic model determine the rate limiting step, vacancy formation enthalpy, ex-solution enthalpy, and activation energy for particle growth. The ex-solved particles are tightly socketed, preventing interactions among them over 800 °C. Furthermore, we obtain the first direct clarification of the active reaction site for CO oxidationthe Co-oxide interface, agreeing well with density functional theory calculations.

In photoelectrochemical (PEC) water splitting, BiVO4 is considered the most promising photoanode material among metal oxide semiconductors because of its relatively narrow optical bandgap and suitable band structure for water oxidation. Nevertheless, until now, the solar-to-hydrogen conversion efficiency of BiVO4 has shown significant limitations for commercialization because of its poor charge transport. Various strategies, including the formation of a heterojunction and doping of electron donors, have been implemented to enhance the charge transport efficiency; however, fundamental approaches are required for further enhancement. In this regard, we report the fundamental approach for BiVO4 thin film photoanodes by fabricating epitaxial oxide thin films with different crystallographic orientations for PEC water splitting. The crystalline anisotropy generally reveals distinct physical phenomena along different crystallographic orientations. In the same vein, in terms of the anisotropic properties of BiVO4, the electrical conductivity of BiVO4 is greater along the ab-plane than along the c-axis. Consequently, as the crystallographic orientation of the BiVO4 thin film changes from (001) to (010), the charge transport properties in the epitaxial BiVO4 thin film are significantly enhanced. Thus, at 1.23 VRHE, the photocurrent density of the epitaxial BiVO4 (010) thin film (2.29 mA cm–2) is much higher than that of the epitaxial BiVO4 (001) thin film (0.74 mA cm–2) because of significant enhancement in charge transport properties even for undoped BiVO4. These results strongly suggest that the growth of epitaxial BiVO4 thin films with specific crystallographic orientations has great potential to considerably improve the charge transport efficiency of photoanodes for solar water splitting.

This study examined the role of calcineurin, a major calcium‐dependent protein phosphatase, in dephosphorylating Ser‐9 and activating glycogen synthase kinase‐3β (GSK‐3β). Treatment with calcineurin inhibitors increased phosphorylation of GSK‐3β at Ser‐9 in SH‐SY5Y human neuroblastoma cells. The over‐expression of a constitutively active calcineurin mutant, calcineurin A beta (1–401), led to a significant decrease in phosphorylation at Ser‐9, an increase in the activity of GSK‐3β, and an increase in the phosphorylation of tau. Km of calcineurin for a GSK‐3β phosphopeptide was 469.3 μM, and specific activity of calcineurin was 15.2 nmol/min/mg. In addition, calcineurin and GSK‐3β were co‐immunoprecipitated in neuron‐derived cells and brain tissues, and calcineurin formed a complex only with dephosphorylated GSK‐3β. We conclude that in vitro, calcineurin can dephosphorylate GSK‐3β at Ser‐9 and form a stable complex with GSK‐3β, suggesting the possibility that calcineurin regulates the dephosphorylation and activation of GSK‐3βin vivo.

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Clinical isolates of Escherichia coli and Klebsiella pneumoniae producing extended-spectrum ␤-lactamases or plasmid-mediated AmpC ␤-lactamases were screened for qnrA and qnrB genes. QnrB was present in 54 of 54 DHA-1-producing K. pneumoniae isolates and 10 of 45 SHV-12-producing ones, suggesting that the distribution of plasmids conferring resistance to extended-spectrum cephalosporins and quinolones in clinical isolates of K. pneumoniae is widespread.Since the first plasmid-mediated quinolone resistance-conferring gene (qnr) was discovered in a Klebsiella pneumoniae isolate from Alabama (7), Qnr determinants have been identified worldwide (2,9,13,15). A frequent association of quinolone resistance with the production of extended-spectrum ␤-lactamases (ESBLs) has been noticed and was explained by the selective pressures of multiple antibiotics and plasmidmediated qnr (3,9,12,15,17). At present, several qnrA-positive isolates have been found to express ESBLs, such as SHV-5, SHV-7, CTX-M-15, and VEB-1, or plasmid-mediated AmpC enzymes, such as DHA-1 (9, 17). The association of qnrB and SHV-12 was recently described (3).In order to study the prevalence of Qnr determinants and to identify ESBLs or plasmid-mediated AmpC ␤-lactamases associated with qnr genes, we screened 239 isolates of Escherichia coli and K. pneumoniae producing variable ESBLs or plasmidmediated AmpC ␤-lactamases for qnrA and qnrB.(This study was presented at the 44th IDSA meeting, Toronto, Ontario, Canada, 2006.) Twenty-seven E. coli strains and 62 K. pneumoniae strains were obtained from the blood isolate collection of Seoul National University Children's Hospital (SNUCH). These isolates were collected from 1993 to 2005 and were identified as producers of an ESBL or a plasmid-mediated AmpC ␤-lactamase (part of these data were published previously [6]). Forty-nine isolates of K. pneumoniae known to produce ESBLs or to have a plasmid-mediated AmpC enzyme were recruited from the blood isolate collection of Seoul National University Hospital (SNUH) during the 5 years from 1998 to 2002 (10). Fifty-four E. coli strains and 23 K. pneumoniae strains, selected for resistance to cefoxitin and extended-spectrum cephalosporins (ESCs), were obtained from Hanyang University Hospital (HUH), a tertiary-care teaching hospital in Seoul, from 2003 to 2005. Twenty-four K. pneumoniae isolates were collected from Korea University Hospital (KUH), Seoul, in 2005 and were chosen because of their ESC resistance. Only one isolate from each patient was included in all collections. Thus, a total of 81 E. coli strains and 158 K. pneumoniae strains which produced an ESBL or a plasmid-mediated AmpC were included in this study.Isoelectric focusing (IEF) was performed by the method of Mathew et al. (8) by using a Mini IEF cell system (Bio-Rad, Hercules, CA). Strains carrying plasmids encoding ␤-lactamases TEM-1 (R1), TEM-4 (pUD16), SHV-2 (pMG229), SHV-5 (pAFF2), and CMY-1 (pMVP-1) served as the IEF standards (6). The ␤-lactamase genes from the clinical isolates were amplified a...

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Serum 25(OH)D levels have a positive correlation with pulmonary function. This relationship appears prominent in subjects with susceptibility to pulmonary tuberculosis.

In order to investigate the incidence, clinical and microbiologic characteristics of Clostridium difficile infection (CDI) in Korea, a prospective observational study was performed. From September 2008 through January 2010, all patients whose stool was tested for toxin assay A&B and/or C. difficile culture were studied for clinical characteristics. Toxin types of the isolates from stool were tested. The mean incidence of CDI per 100,000 patient-days was 71.6 by month (range, 52.5-114.0), and the ratio of CDI to antibiotic-associated diarrhea was 0.23. Among 200 CDI patients, 37.5% (75/200) was severe CDI based on severity score. Clinical outcome of 189 CDI was as followed; 25.9% (49/189) improved without treatment, 84.3% (118/140) achieved clinical cure and attributed mortality was 0.7% (1/140) with the treatment. Recurrence rate was 21.4% (30/140) and cure without recurrence was 66.4% (93/140). The most common type of toxin was toxin A-positive/toxin B-positive strain (77.5%), toxin A-negative/toxin B-positive strains or binary toxin-producing strains comprised 15.4% or 7.1%, respectively. In conclusion, the incidence of CDI in Korea is a little higher than other reports during the non-epidemic setting. We expect that the change of epidemiology and clinical severity in CDI can be evaluated based on these results.