Objectives: This study examined the mediating effects of smartphone dependence on the relationship between anxiety and delayed bedtime and analyzed the group differences based on gender and economic difficulties caused by the COVID-19 pandemic among Korean adolescents. Methods: Data from 4254 middle school students living in metropolitan areas and cohabiting with highly educated parents were analyzed using the 2020 Korea Youth Risk Behavior Survey.The participants were divided into four groups based on gender and economic difficulties caused by COVID-19. T-tests, analysis of variance, and Pearson correlation analysis were conducted on each variable. The Baron–Kenny method and Sobel tests were used to verify the mediating effects. Results: Female students showed higher levels of anxiety, smartphone dependence, and delayed bedtime. Groups experiencing economic difficulties due to COVID-19 reported higher levels of anxiety and smartphone dependence. Across all groups, positive correlations were observed between anxiety, smartphone dependence, and delayed bedtime. Smartphone dependence partially mediated the relationship between anxiety and delayed bedtime, except in the group of male students experiencing economic difficulties caused by COVID-19. Conclusion This study confirmed the associations between anxiety, smartphone dependence, and delayed bedtime among adolescents, suggesting the need for interventions related to smartphone use to support the mental health of adolescents in stressful situations.

Objectives: This study examined the mediating effects of smartphone dependence on the relationship between anxiety and delayed bedtime and analyzed the group differences based on gender and economic difficulties caused by the COVID-19 pandemic among Korean adolescents. Methods: Data from 4254 middle school students living in metropolitan areas and cohabiting with highly educated parents were analyzed using the 2020 Korea Youth Risk Behavior Survey.The participants were divided into four groups based on gender and economic difficulties caused by COVID-19. T-tests, analysis of variance, and Pearson correlation analysis were conducted on each variable. The Baron–Kenny method and Sobel tests were used to verify the mediating effects. Results: Female students showed higher levels of anxiety, smartphone dependence, and delayed bedtime. Groups experiencing economic difficulties due to COVID-19 reported higher levels of anxiety and smartphone dependence. Across all groups, positive correlations were observed between anxiety, smartphone dependence, and delayed bedtime. Smartphone dependence partially mediated the relationship between anxiety and delayed bedtime, except in the group of male students experiencing economic difficulties caused by COVID-19. Conclusion This study confirmed the associations between anxiety, smartphone dependence, and delayed bedtime among adolescents, suggesting the need for interventions related to smartphone use to support the mental health of adolescents in stressful situations.

Objectives: This study examined the mediating effects of smartphone dependence on the relationship between anxiety and delayed bedtime and analyzed the group differences based on gender and economic difficulties caused by the COVID-19 pandemic among Korean adolescents. Methods: Data from 4254 middle school students living in metropolitan areas and cohabiting with highly educated parents were analyzed using the 2020 Korea Youth Risk Behavior Survey.The participants were divided into four groups based on gender and economic difficulties caused by COVID-19. T-tests, analysis of variance, and Pearson correlation analysis were conducted on each variable. The Baron–Kenny method and Sobel tests were used to verify the mediating effects. Results: Female students showed higher levels of anxiety, smartphone dependence, and delayed bedtime. Groups experiencing economic difficulties due to COVID-19 reported higher levels of anxiety and smartphone dependence. Across all groups, positive correlations were observed between anxiety, smartphone dependence, and delayed bedtime. Smartphone dependence partially mediated the relationship between anxiety and delayed bedtime, except in the group of male students experiencing economic difficulties caused by COVID-19. Conclusion This study confirmed the associations between anxiety, smartphone dependence, and delayed bedtime among adolescents, suggesting the need for interventions related to smartphone use to support the mental health of adolescents in stressful situations.

Objectives: This study examined the mediating effects of smartphone dependence on the relationship between anxiety and delayed bedtime and analyzed the group differences based on gender and economic difficulties caused by the COVID-19 pandemic among Korean adolescents. Methods: Data from 4254 middle school students living in metropolitan areas and cohabiting with highly educated parents were analyzed using the 2020 Korea Youth Risk Behavior Survey.The participants were divided into four groups based on gender and economic difficulties caused by COVID-19. T-tests, analysis of variance, and Pearson correlation analysis were conducted on each variable. The Baron–Kenny method and Sobel tests were used to verify the mediating effects. Results: Female students showed higher levels of anxiety, smartphone dependence, and delayed bedtime. Groups experiencing economic difficulties due to COVID-19 reported higher levels of anxiety and smartphone dependence. Across all groups, positive correlations were observed between anxiety, smartphone dependence, and delayed bedtime. Smartphone dependence partially mediated the relationship between anxiety and delayed bedtime, except in the group of male students experiencing economic difficulties caused by COVID-19. Conclusion This study confirmed the associations between anxiety, smartphone dependence, and delayed bedtime among adolescents, suggesting the need for interventions related to smartphone use to support the mental health of adolescents in stressful situations.

The anti-melanogenic activity of 259 actinomycete strains was tested, and based on the results for the inhibition of mushroom tyrosinase activity and the reduction in melanin content, Micromonospora sp. JCS1 and JCS7 were selected as the strains with the highest anti-melanogenic potential. The activity-guided fractionation of extracts from JCS1 and JCS7 led to the isolation of the dipeptides cyclo(L-Phenyl alanine (Phe)-L-Proline (Pro)) (1) and cyclo(L-Tryptophan (Trp)-L-Proline (Pro)) (2). These two compounds were tested for their inhibition of mushroom tyrosinase by monitoring L-DOPA levels and melanin production. Cyclo(L-Phe-L-Pro) (1) and cyclo(L-Trp-L-Pro) (2) were thus confirmed to have the potential for use in functional whitening cosmetics containing actinomycete-derived secondary metabolites.

We investigated the effect of phenylephrine (PE)- and isoproterenol (ISO)-induced cardiac hypertrophy on subcellular localization and expression of caveolin-3 and STAT3 in H9c2 cardiomyoblast cells. Caveolin-3 localization to plasma membrane was attenuated and localization of caveolin-3 to caveolae in the plasma membrane was 24.3% reduced by the catecholamine-induced hypertrophy. STAT3 and phospho-STAT3 were up-regulated but verapamil and cyclosporin A synergistically decreased the STAT3 and phospho-STAT3 levels in PE- and ISO-induced hypertrophic cells. Both expression and activation of STAT3 were increased in the nucleus by the hypertrophy. Immunofluorescence analysis revealed that the catecholamine-induced hypertrophy promoted nuclear localization of pY705-STAT3. Of interest, phosphorylation of pS727-STAT3 in mitochondria was significantly reduced by catecholamine-induced hypertrophy. In addition, mitochondrial complexes II and III were greatly down-regulated in the hypertrophic cells. Our data suggest that the alterations in nuclear and mitochondrial activation of STAT3 and caveolae localization of caveolin-3 are related to the development of the catecholamine-induced cardiac hypertrophy.
Animals ; Catecholamines/*pharmacology ; Caveolae/*metabolism ; Caveolin 3/*metabolism ; Cell Line ; Hypertrophy/metabolism ; Mitochondria/*metabolism ; Myocardium/cytology/*pathology ; Myocytes, Cardiac/cytology/*drug effects/metabolism ; Rats ; STAT3 Transcription Factor/*metabolism

A chiral derivatization strategy with phenylglycine methyl ester (PGME) was employed to develop a straightforward method to determine the absolute configurations of N,N-dimethyl amino acids. The PGME derivatives were analyzed using liquid chromatography-mass spectrometry to identify the absolute configurations of various N,N-dimethyl amino acids based on their elution time and order. The established method was applied to assign the absolute configuration of the N,N-dimethyl phenylalanine in sanjoinine A (4), a cyclopeptide alkaloid isolated from Zizyphi Spinosi Semen widely used as herbal medicine for insomnia. Sanjoinine A displayed production of nitric oxide (NO) in LPS-activated RAW 264.7 cells.