University of Macau

About: University of Macau is a education organization based out in Macao, Macau, China. It is known for research contribution in the topics: Population & Control theory. The organization has 6636 authors who have published 18324 publications receiving 327384 citations. The organization is also known as: UM & UMAC.

Explicating the influences that explain intention to use technology among English teachers in China

Abstract: Given the paradox between pervasive promotion of technology use in English teaching and lack of studies about teachers’ technology acceptance in China, this study aims to examine intentions of Engl...

Proneness to Boredom Mediates Relationships Between Problematic Smartphone Use With Depression and Anxiety Severity

Abstract: Research demonstrates that depression and anxiety symptom severity are related to problematic smartphone use (PSU). However, less is known about variables mediating these relationships. This study ...

Calycosin promotes angiogenesis involving estrogen receptor and mitogen-activated protein kinase (MAPK) signaling pathway in zebrafish and HUVEC.

Abstract: Background Angiogenesis plays an important role in a wide range of physiological processes, and many diseases are associated with the dysregulation of angiogenesis. Radix Astragali is a Chinese medicinal herb commonly used for treating cardiovascular disorders and has been shown to possess angiogenic effect in previous studies but its active constituent and underlying mechanism remain unclear. The present study investigates the angiogenic effects of calycosin, a major isoflavonoid isolated from Radix Astragali, in vitro and in vivo. Methodology Tg(fli1:EGFP) and Tg(fli1:nEGFP) transgenic zebrafish embryos were treated with different concentrations of calycosin (10, 30, 100 microM) from 72 hpf to 96 hpf prior morphological observation and angiogenesis phenotypes assessment. Zebrafish embryos were exposed to calycosin (10, 100 microM) from 72 hpf to 78 hpf before gene-expression analysis. The effects of VEGFR tyrosine kinase inhibitor on calycosin-induced angiogenesis were studied using 72 hpf Tg(fli1:EGFP) and Tg(fli1:nEGFP) zebrafish embryos. The pro-angiogenic effects of calycosin were compared with raloxifene and tamoxifen in 72 hpf Tg(fli1:EGFP) zebrafish embryos. The binding affinities of calycosin to estrogen receptors (ERs) were evaluated by cell-free and cell-based estrogen receptor binding assays. Human umbilical vein endothelial cell cultures (HUVEC) were pretreated with different concentrations of calycosin (3, 10, 30, 100 microM) for 48 h then tested for cell viability and tube formation. The role of MAPK signaling in calycosin-induced angiogenesis was evaluated using western blotting. Conclusion Calycosin was shown to induce angiogenesis in human umbilical vein endothelial cell cultures (HUVEC) in vitro and zebrafish embryos in vivo via the up-regulation of vascular endothelial growth factor (VEGF), VEGFR1 and VEGFR2 mRNA expression. It was demonstrated that calycosin acted similar to other selective estrogen receptor modulators (SERMs), such as raloxifene and tamoxifen, by displaying selective potency and affinity to estrogen receptors ERalpha and ERbeta. Our results further indicated that calycosin promotes angiogenesis via activation of MAPK with the involvement of ERK1/2 and ER. Together, this study revealed, for the first time, that calycosin acts as a selective estrogen receptor modulator (SERM) to promote angiogenesis, at least in part through VEGF-VEGFR2 and MAPK signaling pathways.

Induction of ferroptosis and mitochondrial dysfunction by oxidative stress in PC12 cells.

Abstract: Neurodegenerative diseases (NDD) are typically associated with neuron loss in nervous system areas. Interventions with related death mechanisms may ameliorate NDD progression. Oxidative stress plays an important role in NDD cell death routines. However, tert-butylhydroperoxide (t-BHP), a widely used oxidative stress stimulus, induces neural cell death through a mechanism that remains elusive. In our study, the ferroptosis marker events occurred after co-treatment with 100 μM t-BHP for 1 h, all of which were reversed in the presence of the ferroptosis inhibitor ferrostatin-1 (Fer-1) and the iron chelator deferoxamine, implying the occurrence of ferroptosis. Moreover, mitochondrial dysfunction accompanied by a decreased in membrane potential and ATP production, increased mitochondrial ROS generation. Furthermore, this mitochondrial dysfunction could be reversed by Fer-1. In addition, JNK1/2 and ERK1/2 were activated upstream of the ferroptosis and mitochondrial dysfunction. In summary, these data suggest that ferroptosis, coupled with mitochondrial dysfunction, was involved in t-BHP-induced PC12 death. JNK1/2 and ERK1/2 played important roles in t-BHP-induced cell death. Overall, this study might provide clues to the oxidative stress-based strategies for cell protection in NDD.

The Determinants of Bank Performance in China

Abstract: China's banking system has undergone gradual reform since 1978, with a view to improving efficiency and resource allocation. Recent reforms have focused on allowing banks to list some shares on domestic and foreign exchanges, greater foreign equity participation in Chinese banks, and the establishment of new rural financial institutions. To assess whether these objectives have been achieved, this study looks at how well different types of Chinese banks have performed between 1999 and 2006, and tests for the factors influencing performance. It also evaluates four measures of performance to identify which one, if any, is superior. The independent variables include the standard financial ratios, those which reflect more recent reforms (listing, bank type, the extent of foreign ownership) and macroeconomic variables. The results suggest economic value added and the net interest margin do better than the more conventional measures of profitability, namely ROAE and ROAA. Some macroeconomic variables and financial ratios are significant with the expected signs. Though the type of bank is influential, bank size is not. Neither the percentage of foreign ownership nor bank listings has a discernable effect.