3,696 research outputs found

    The CKM matrix from anti-SU(7) unification of GUT families

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    We estimate the CKM matrix elements in the recently proposed minimal model, anti-SU(7) GUT for the family unification, [ 3 ]+2 [ 2 ]+8 [ 1ˉ ][\,3\,]+2\,[\,2\,]+8\,[\,\bar{1}\,]+\,(singlets). It is shown that the real angles of the right-handed unitary matrix diagonalizing the mass matrix can be determined to fit the Particle Data Group data. However, the phase in the right-handed unitary matrix is not constrained very much. We also includes an argument about allocating the Jarlskog phase in the CKM matrix. Phenomenologically, there are three classes of possible parametrizations, \delq=\alpha,\beta, or γ\gamma of the unitarity triangle. For the choice of \delq=\alpha, the phase is close to a maximal one.Comment: 11 pages of LaTex file with 2 figure

    Corporate Social Responsibility and Corporate Financial Performance: Evidence from Korea

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    This paper studies the empirical relation between corporate social responsibility (CSR) and corporate financial performance in Korea using a sample of 1122 firm-years during 2002-2008. We measure corporate social responsibility by both an equal-weighted CSR index and a stakeholder-weighted CSR index suggested by Akpinar et al. (2008). Corporate financial performance is measured by ROE, ROA and Tobin’s Q. We find a positive and significant relation between corporate financial performance and the stakeholder-weighted CSR index, but not the equal-weighted CSR index. This finding is robust to alternative model specifications and several additional tests, providing evidence in support of instrumental stakeholder theory.corporate social responsibility; corporate financial performance; KEJI index; instrumental stakeholder theory

    Phytochemical profile, antioxidant, antimicrobial and antipancreatic lipase activities of fermented Camellia japonica L leaf extracts

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    Purpose: To investigate the probable antioxidant, antimicrobial and  antipancreatic lipase effects of fermented Camellia japonica leaf extracts.Methods: Camellia japonica leaves fermented with Nuruk were extracted using methanol and ethanol. Total phenolic, flavonoid, carotenoid and L-ascorbic acid contents were determined by UV-visible spectrophotometry. The antioxidant activities of these extracts were determined by free radical scavenging, ferrous ion chelating and reducing power assays. Their  antimicrobial properties against Gram-positive Staphylococcus epidermidis and Bacillus subtilis, and Gram-negative Klebsiella pneumonia and Escherichia coli bacteria were evaluated by disc diffusion method. Inhibition of pancreatic lipase was measured based on the hydrolytic reaction of p-nitrophenyl butyrate with pancreatic lipase.Results: The ethanol extracts of fermented Camellia japonica leaves exhibited higher phenolic (32274mg GAE/100 g) and flavonoid (20519 mg RE/100 g) contents with higher superoxide (IC50 = 0.23  mg/mL), hydrogen peroxide (IC50 = 0.28 mg/mL) radical scavenging and ferrous ion chelating (IC50 = 0.21 mg/mL) activities than those of methanol. These ethanol extracts also showed higher antimicrobial activities against all bacterial strains tested with higher inhibitory effects on pancreatic lipase than methanol extracts.Conclusion: The results highlight the possible use of fermented Camellia japonica leaf extracts as a source of antioxidant, antibacterial and antiobesity agents. Ethanol is recommended as solvent for extracting antioxidants, antibacterial and antiobesity agents from this plant.Keywords: Antioxidant activity, Antimicrobial activity, Fermented Camellia japonica extracts, Pancreatic lipase inhibitio

    GENOTOXICITY OF N-HYDROXY AND AMINOPHENOL METABOLITES OF 2,6- AND 3,5-DIMETHYLANILINE AT THE HYPOXANTHINEGUANINE PHOSPHORIBOSYLTRANSFERASE LOCUS IN TK6 CELLS

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    Objective: The objective of this study as to characterize the genotoxicity of reactive metabolites of 2,6-dimethylaniline (2,6-DMA) and 3,5-DMA in the hypoxanthineguanine phosphoribosyltransferase (HPRT) gene of human lymphoblastoid TK6 cells.Methods: Cultures were exposed to N-hydroxylamine and aminophenol metabolites of 2,6- and 3,5-DMA for 1 h in serum-free medium. Cell survival 24 h after exposure was determined by trypan blue exclusion. Cells were then subcultured for 7–10 days to allow to phenotypic expression of HPRT mutants. After the expression period, cells were plated in the presence of 2 μg/ml 6-thioguanine for the selection of HPRT mutants. Plating efficiency was determined and mutant fraction calculated. Electron paramagnetic resonance (EPR) was also used to determine whether 3,5- dimethylaminophenol (DMAP) produced reactive oxygen species (ROS).Results: All of the metabolites tested were cytotoxic to these cells but exhibited a considerable variation in potency. The aminophenol metabolites of 2,6- and 3,5-DMA were considerably more toxic than the corresponding N-hydroxylamines. Furthermore, each metabolite of 3,5-DMA was more toxic than its 2,6-DMA counterpart; N-OH-3,5-DMA and 3,5-DMAP were clearly mutagenic at a level of 50 μM. EPR studies showed intracellular oxidative stress induced under 3,5-DMAP treatment.Conclusions: Our findings suggest that genotoxic responses of 2,6- and 3,5-DMA are mediated through the generation of ROS by hydroxylamine and/ or aminophenol metabolites.Â

    METABOLIC ACTIVATION OF 2,6-DIMETHYLANILINE: MUTATIONAL SPECIFICITY IN THE GPT GENE OF AS52 CELLS

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    Objective: The purpose of the current work was to characterize the mechanisms of cytotoxicity and mutagenesis of a potential human bladder carcinogen 2,6-dimethylaniline (2,6-DMA).Methods: Chinese hamster ovary (CHO) AS52 cells were exposed to either human S9 activated 2,6-DMA for 6 h or its N-hydroxylamine and aminophenol metabolites for 1 h in serum-free medium. Cell survival was determined by trypan blue exclusion 24 h after treatment, and 6-thioguanine-resistant mutants at the xanthine-guanine phosphoribosyl transferase (gpt) gene locus were assessed with doses, of which relative survival is 30% or more. Nested polymerase chain reaction-based deletion analysis was also performed.Results: AS52 cells exhibited a dose-dependent increase in cytotoxicity and mutant fraction on treatment of 2,6-DMA and its metabolites but show a considerable variation in potency with aminophenol metabolites having the highest potency and parent compound at least; at the highest 2,6-dimethylaminophenol dose (10 μM), the mutant fraction in AS52 cells was 8-fold (13.2×10−5) greater than the spontaneous fraction of 1.62×10−5. Total deletion of the gpt gene sequences was found in 1 (4%) spontaneous and 2 (6%) the 6-thioguanine mutants generated by N-hydroxy-2,6-DMA.Conclusions: These findings indicate the mutagenicity of 2,6-DMA at the gpt gene, which is mediated through hydroxylamine and aminophenol metabolites, and contribute to the elucidation of mechanisms through which 2,6-DMA may exert its effects in vivo

    three essays in development economics

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    Thesis(Doctoral) --KDI School:Ph.D in Development Policy,2018I. Role Model Effects of Female Leadership Training on Girl’s Education II. Reforestation in South Korea and Its Consequences III. The Impact of Female Leadership in Rural Development Project in MyanmardoctoralpublishedMin Young SEO

    Therapeutic and developmental design: the relationship between spatial enclosure and impaired elder-child social interaction

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    Social interaction and the availability of meaningful activities promote the physical and psychological well-being of children and older adults. The development of social interaction is closely related to physical and social environments that complement the therapeutic needs of cognitively impaired elders and the developmental needs of young children. This study examined the effects of the degree of spatial enclosure on social interaction between these two groups during physical exercise in an assisted living facility co-located with a childcare center. The multi-methodological approach allowed for triangulation and employed the following techniques: naturalistic observation, a Web-based and mail out survey, an experiment, semi-structured interviews, sequential analysis, nonparametric analysis, and content analysis. The findings of this study demonstrated that a semi-enclosed spatial plan most influenced the prosocial behavior of older adults and young children. These elder-child prosocial behaviors were likely facilitated by a perception of adequate personal space, openness, and possible spaces for prospect and refuge within the semi-enclosed spatial plan. Elder-child social interaction was positively influenced by several programmatic factors which gave participants some sense of control. These findings led to design recommendations for creating appropriate developmental and therapeutic environments for children and older adults in intergenerational care settings. Recommendations were that a satisfactory balance be maintained between openness and enclosure as these stimulate elder-child social interaction
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