MiR-155 protects against sepsis-induced cardiomyocyte apoptosis via activation of NO/cGMP signaling pathway by eNOS

Purpose: To examine the impact of miR-155 on sepsis-induced myocardial apoptosis and heart failure, and to explore its molecular mechanism. Methods: Mice were divided into four groups and septic myocardial dysfunction was induced by intraperitoneal injection of lipopolysaccharide (LPS, 5 mg/kg). The LPS stimulation expression of miR-155 levels was determined by real time-polymerase chain reaction (RT-PCR). In vivo, echocardiography and TUNEL staining were used to investigate the effects of miR-155 in inhibiting cardiac function and myocardial apoptosis. Changes in the expression of eNOS when miR-155 was overexpressed or inhibited were determined by RT-PCR, while double luciferase gene assay assessed the relationship between eNOS and miR-155, eNOS, expression of iNOS, SGC alpha 1, and PKG protein. Results: MiR-155 was significantly increased after LPS stimulation (p < 0.01). In vitro, the inhibition of miR-155 by antagomiR significantly down-regulated the apoptosis of cardiomyocytes (p < 0.05), while overexpression of miR-155 by agomiR significantly up-regulated the apoptosis of cardiomyocytes (p < 0.05). In vivo, ejection fraction, fractional shortening and heart weight were significantly increased (p < 0.05), while apoptosis was significantly decreased (p < 0.05). MiR-155 negatively regulated the expression of eNOS (p < 0.01), and targeted the expression of eNOS mRNA (p < 0.001). In addition, the expression of eNOS, sGCα1 and PKA were significantly up-regulated (p < 0.05), while the expression of iNOS was significantly down-regulated (p < 0.05) after the inhibition of miR-155 in LPS mouse model. Conclusion: MiR-155 regulates sepsis-induced cardiomyocyte apoptosis and heart failure through eNOS /NO/cGMP signaling pathway. Thus, these findings can potentially facilitate the development of an effective strategy for management of heart failure

Spatial Effects of Digital Economy on Tourism Development: Empirical Research Based on 284 Cities at the Prefecture and Higher Levels in China

The digital economy, an essential engine for the high-quality development of China's economy, has the potential to become a breakthrough in promoting the rapid recovery of tourism. From a spatial perspective, this study used panel data from 284 prefecture-level and higher cities in China from 2011 to 2019 and constructed a spatial Durbin model (SDM) to empirically test the spatial effect and mechanism of the digital economy on tourism development. (1) Digital economy and tourism development showed significant positive global spatial autocorrelation during the study period. Hotspots of the digital economy have long been located in southeastern coastal areas, and cold spots in central and western China have shrunk significantly. Tourism development hotspots are mainly distributed in the Yangtze River Delta urban agglomerations and in Yunnan, Guangxi, Guizhou, and Chongqing. Cold spots were distributed in the central and western cities of the Shandong Peninsula and gradually expanded southward. (2) In China, the digital economy has a significant direct effect and positive spatial spillover effect, which was confirmed by a series of robustness tests were conducted. From the perspective of different regions, although the direct effect was significantly positive in all regions, the influence coefficient in the eastern region was significantly larger than that in the central, western, and northeastern regions. The spatial spillover effect is entirely significant in the eastern region, partly significant in the central and northeastern regions, and not significant in the western region, indicating that "digital segregation" exists in the western region. (3) The positive spatial spillover effect of the digital economy on tourism development is optimal at 300 km. Subsequently, the spatial spillover effect followed the law of geographical distance attenuation. The spatial spillover effect reaches the critical point of the practical effect at 800 km and almost disappears at 1500 km. (4) Among the digital economy components, digital infrastructure, digital industry development, and digital inclusive finance can significantly promote local tourism development. However, only digitally inclusive finance has a significant positive spatial spillover effect, and the effects of the remaining components are insignificant. This study constructs an analytical framework for the spatial effects of the digital economy on tourism development and conducts rigorous empirical research to compensate for the limitations of current research from a local perspective. This study also examined the spatial effects of various components of the digital economy, which helped identify the source of the impact of the digital economy on tourism development more accurately. In addition, the regional heterogeneity and distance attenuation law of the spatial effect of the digital economy on tourism development were analyzed, and customized policy implications were proposed based on the research conclusions. Overall, this study has essential reference value for achieving high-quality tourism development and expanding the scope of digital economy application

THE VIBRATIONAL PROPERTIES OF CHINESE FIR WOOD DURING MOISTURE SORPTION PROCESS

The vibrational properties of Chinese fir (Cunninghamia lanceolata) wood were investigated in this study as a function of changes in moisture content (MC) and grain direction. The dynamic modulus of elasticity (DMOE) and logarithmic decrement (δ) were examined using a cantilever beam vibration testing apparatus. It was observed that DMOE and δ of wood varied widely during moisture adsorption and desorption. The DMOE of wood conditioned by the adsorption process showed significant increases during the later stages of conditioning when the MC scarcely changed. However, with the desorption process, the DMOE did not increase as much during the later stages of conditioning, though they increased during the early stages of conditioning when the MC greatly decreased. These results suggest that wood in an unstable state, caused via the existing state of moisture, shows different vibrational behaviors. Furthermore, the parallel to grain direction showed much higher DMOE and lower δ when compared to the perpendicular to grain direction. The variation of vibrational properties between parallel and perpendicular to grain direction under constant MC and during moisture adsorption process could be attributed due to the microscopic, macroscopic molecular, as well as chemical constituents of wood

Can Tourism Development Help Improve Urban Liveability? An Examination of the Chinese Case

The emergence of “urban diseases” has aroused people’s widespread concern about urban liveability. Therefore, it is worth studying whether tourism, as a “smokeless industry” can improve it. In this article, the benchmark model, the spatial Durbin model (SDM), and the panel threshold model (PTM) are constructed to test the impact of tourism development on urban liveability based on the data from 284 prefecture-level and above cities in China for the period 2004–2019. The results show that tourism development can significantly contribute to the improvement of urban liveability. Meanwhile, the positive impact of tourism development on the liveability of neighboring cities through spatial spillover effects is still valid in eastern, central, and western China, but the effect is much larger in the eastern and central cities than in the western cities. Moreover, tourism development has positive nonlinear effects on urban liveability, and the marginal effects are clearly decreasing after crossing the first and second thresholds. Finally, specific recommendations are proposed for tourism development to improve urban liveability