2,891 research outputs found

    Mechanochemical Synthesis of Active Magnetite Nanoparticles Supported on Charcoal for Facile Synthesis of Alkynyl Selenides by C−H Activation

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    Magnetite (Fe3O4) nanoparticles supported on charcoal, graphene, or SBA‐15 were prepared by a simple solid‐state grinding technique and subsequent thermal treatment. The Fe3O4 nanoparticles supported on activated charcoal exhibited high catalytic activity and furnished good yields of the alkynyl selenide product in the cross‐coupling reaction of diphenyl diselenide and alkynes through activation of C−H and Se−Se bonds under ecofriendly conditions, surpassing traditional copper‐based catalysts to effect the same organic transformation.Alkynes of fun: Fe3O4 nanoparticles separately supported on charcoal, graphene, and SBA‐15 are prepared by solid‐state grinding and subsequent thermal treatment. The Fe3O4 nanoparticles supported on activated charcoal exhibit high catalytic activity and furnish good yields of alkynyl selenide products in the cross‐coupling reactions of diphenyl diselenide with alkynes through C−H and Se−Se bond activation under ecofriendly conditions.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/137502/1/cctc201600280-sup-0001-misc_information.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/137502/2/cctc201600280_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/137502/3/cctc201600280.pd

    HI 21 cm Emission Line Study of Southern Galactic Supernova Remnants

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    We have searched for HI 21 cm line emission from shocked atomic gas associated with southern supernova remnants (SNRs) using data from the Southern Galactic Plane Survey. Among the 97 sources studied, we have detected 10 SNRs with high-velocity HI emission confined to the SNR. The large velocity and the spatial confinement suggest that the emission is likely from the gas accelerated by the SN blast wave. We also detected 22 SNRs which show HI emission significantly brighter than the surrounding regions over a wide (>10>10\kms) velocity interval. The association with these SNRs is less certain. We present the parameters and maps of the excess emission in these SNRs. We discuss in some detail the ten individual SNRs with associated high-velocity HI emission.Comment: 17 pages, 8 figures, accepted for publication in JKAS (Journal of the Korean Astronomical Society

    Factors influencing the health-related quality of life in Korean menopausal women: a cross-sectional study based on the theory of unpleasant symptoms

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    Purpose Based on the theory of unpleasant symptoms (TOUS), this study aimed to examine the direct effect of antecedent factors on health-related quality of life (HRQoL) and its indirect effect via symptoms in Korean women during the late menopausal transition (MT) and early postmenopause. Methods This cross-sectional survey employed a descriptive correlational research design. The respondents were 152 middle-aged women 40 to 60 years with an intermenstrual interval of 60 days or more (late MT) or less than 5 years from the last menstrual period (early postmenopause). The respondents were recruited through convenience sampling in Busan, Korea, from December 1, 2020, to January 31, 2021. Based on the TOUS, self-report data were collected on perceived health status, psychological distress, social support, menopausal symptoms, and HRQoL. The collected data were analyzed using descriptive statics, independent t-test, one-way analysis of variance, Pearson’s correlation coefficient, and the Hayes’ PROCESS macro. Results TOUS was supported on this sample (n=152) of Korean women during the late MT and early postmenopause. Perceived health status, psychological distress, and social support had significant direct relationships with HRQoL. Menopausal symptoms had significant indirect relationships between antecedent factors (perceived health status, psychological distress, and social support) and partially mediated HRQoL. Conclusion The findings of this study indicate that menopausal symptoms play an important role as an intervening factor of HRQoL in women during the late MT and early postmenopause. Therefore, women need an integrated program that manages antecedent factors and menopausal symptoms to improve HRQoL in these menopausal stages

    Prevalence of sarcopenia and sarcopenic obesity in Korean adults: The Korean Sarcopenic Obesity Study (KSOS)

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    *Context:* Sarcopenic obesity (SO), a combination of excess weight and reduced muscle mass and/or strength, is suggested to be associated with an increased risk of adverse health outcomes. 
*Objectives:* To examine the prevalence and characteristics of Sarcopenic and SO defined by using different indices such as Appendicular Skeletal muscle Mass (ASM)/height^2^ and Skeletal Muscle Index (SMI (%): skeletal muscle mass (kg)/weight (kg) × 100) for Korean adults. 
*Methods:* 591 participants were recruited from the Korean Sarcopenic Obesity Study (KSOS) which is an ongoing prospective observational cohort study. Analysis was conducted in 526 participants (328 women, 198 men) who had complete data on body composition using Dual X-ray absorptiometry and computed tomography. 
*Results:* The prevalence of sarcopenia and SO increases with aging. Using two or more standard deviations (SD) of ASM/height^2^ below reference values from young, healthy adults as a definition of sarcopenia, the prevalence of sarcopenia and SO was 6.3% and 1.3% in men and 4.1% and 1.7% in women over 60 years of age. However, using two or more SD of SMI, the prevalence of sarcopenia and SO was 5.1% and 5.1% respectively in men and 14.2% and 12.5% respectively in women. As defined by SMI, subjects with SO had 3 times the risk of metabolic syndrome (OR = 3.03, 95% confidence interval (CI) = 1.26-7.26) and subjects with non-sarcopenic obesity had approximately 2 times the risk of metabolic syndrome (OR = 1.89, 95% CI = 1.18-3.02) compared with normal subjects. 
*Conclusion:* Obese subjects with relative sarcopenia were associated with a greater likelihood for metabolic syndrome. As Koreans were more obese and aging, the prevalence of SO and its impact on health outcomes are estimated to be rapidly grow. Further research is requested to establish the definition, cause and consequences of SO.

    Flightless-I Controls Fat Storage in Drosophila

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    Triglyceride homeostasis is a key process of normal development and is essential for the maintenance of energy metabolism. Dysregulation of this process leads to metabolic disorders such as obesity and hyperlipidemia. Here, we report a novel function of the Drosophila flightless-I (fliI) gene in lipid metabolism. Drosophila fliI mutants were resistant to starvation and showed increased levels of triglycerides in the fat body and intestine, whereas fliI overexpression decreased triglyceride levels. These flies suffered from metabolic stress indicated by increased levels of trehalose in hemolymph and enhanced phosphorylation of eukaryotic initiation factor 2 alpha (eIF2??). Moreover, upregulation of triglycerides via a knockdown of fliI was reversed by a knockdown of desat1 in the fat body of flies. These results indicate that fliI suppresses the expression of desat1, thereby inhibiting the development of obesity; fliI may, thus, serve as a novel therapeutic target in obesity and metabolic diseases

    Accurate and Efficient Estimation of Small P-values with the Cross-Entropy Method: Applications in Genomic Data Analysis

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    Small pp-values are often required to be accurately estimated in large scale genomic studies for the adjustment of multiple hypothesis tests and the ranking of genomic features based on their statistical significance. For those complicated test statistics whose cumulative distribution functions are analytically intractable, existing methods usually do not work well with small pp-values due to lack of accuracy or computational restrictions. We propose a general approach for accurately and efficiently calculating small pp-values for a broad range of complicated test statistics based on the principle of the cross-entropy method and Markov chain Monte Carlo sampling techniques. We evaluate the performance of the proposed algorithm through simulations and demonstrate its application to three real examples in genomic studies. The results show that our approach can accurately evaluate small to extremely small pp-values (e.g. 10610^{-6} to 1010010^{-100}). The proposed algorithm is helpful to the improvement of existing test procedures and the development of new test procedures in genomic studies.Comment: 34 pages, 1 figure, 4 table