147 research outputs found
Effects of short-form video app addiction on academic anxiety and academic engagement: The mediating role of mindfulness
IntroductionThe impact of short-form video app addiction on academic performance, including academic anxiety and engagement, has not been adequately explored or addressed.MethodThis study tested the effects of short-form video app addiction on academic anxiety and academic engagement and the mediating role of mindfulness in these relationships. The participants were 1,879 undergraduates in China who completed the Short-Form Video App Addiction Scale, Mindful Attention Awareness Scale, Academic Anxiety Sub-questionnaire of Academic Emotions Questionnaire, and Engagement Scales. Structural equation modelling (SEM) was used to analyse the data.ResultsThe results indicate that short-form video app addiction has significant positive effects on academic anxiety and negative effects on academic engagement. Furthermore, short-form video app addiction has significant indirect effects on academic anxiety and engagement via mindfulness. The proportions of the mediation effects are 19.23 and 51.85%, respectively.DiscussionThe implications and limitations of this study are discussed
Discovery of Potential Inhibitors of Aldosterone Synthase from Chinese Herbs Using Pharmacophore Modeling, Molecular Docking, and Molecular Dynamics Simulation Studies
Aldosterone synthase (CYP11B2) is a key enzyme for the biosynthesis of aldosterone, which plays a significant role for the regulation of blood pressure. Excess aldosterone can cause the dysregulation of the renin-angiotensin-aldosterone system (RAAS) and lead to hypertension. Therefore, research and development of CYP11B2 inhibitor are regarded as a novel approach for the treatment of hypertension. In this study, the pharmacophore models of CYP11B2 inhibitors were generated and the optimal model was used to identify potential CYP11B2 inhibitors from the Traditional Chinese Medicine Database (TCMD, Version 2009). The hits were further refined by molecular docking and the interactions between compounds and CYP11B2 were analyzed. Compounds with high Fitvalue, high docking score, and expected interactions with key residues were selected as potential CYP11B2 inhibitors. Two most promising compounds, ethyl caffeate and labiatenic acid, with high Fitvalue and docking score were reserved for molecular dynamics (MD) study. All of them have stability of ligand binding which suggested that they might perform the inhibitory effect on CYP11B2. This study provided candidates for novel drug-like CYP11B2 inhibitors by molecular simulation methods for the hypertension treatment.</jats:p
Experimental study on unloading creep of sandstone under temperature-seepage coupling conditions
Environmental factors (such as temperature and water) and their coupling effects will change the unloading creep properties of surrounding rock after tunnel excavation, threatening the stability of surrounding rock and the safety maintenance of construction sites. To analyze the effects of temperature, seepage flow, and their coupling on the creep characteristics of sandstone unloading, the triaxial unloading creep test was carried out on the sandstone specimen (φ50 mm×100 mm) by using the self-designed temperature control system and the improved pore water conduction specimen sealing device. The results show that during the creep time of 300 min after unloading the confining stress, the axial compression and radial expansion creep speed increase gradually and then slow down. The strain is mainly radial creep. The decrease in temperature leads to the increase in axial creep deformation and the decrease in radial creep deformation of the dry and saturated specimens. With the increase in seepage water pressure, the axial strain reduces, and the seepage water pressure suppresses the axial creep deformation, while the radial strain increases significantly, and the expansion phenomenon is obvious. Seepage water pressure promotes radial creep deformation. With the increase of seepage water pressure, the axial unloading creep rate decreases and the radial unloading creep rate increases. Under the coupling effect of temperature and seepage, the creep rate curve of unloading is divided into the attenuation stage and the stable stage, and the deformation in the attenuation stage is dominant. The radial creep rate is higher than the axial creep rate, and the fluctuation amplitude of the radial creep rate is small, which reaches stability fast. This study can provide scientific information for the stability evaluation of surrounding rock in deep underground engineering
Study on the breakdown characteristics of multiple-reignition secondary arcs on EHV/UHV transmission lines
A long-gap AC arc with a length of more than ten meters (secondary arc) are normally generated at the short-circuit arc channel after a single-phase-to-ground fault. In previous studies, arc breakdowns of secondary arcs have mainly been considered as electrical breakdowns, ignoring the role of heat in the arc channel. Besides, the extinction-reignition theory of secondary arc, i.e., dielectric strength recovery theory, still lack the support of experimental data. In this study, based on the equivalent experiments performed in the laboratory, the influences of compensation degree of transmission lines, initial recovery voltage gradient of air gap, test current, wind speed, and wind direction on the breakdown characteristics of secondary arcs are studied and statistically analyzed. The laws of the transient recovery voltage (TRV) and of the rate of rise of recovery voltage (RRRV) also studied by considering the influencing factors mentioned above. The results of this study will provide a more complete experimental basis for the theory of extinction–reignition of secondary arcs and a deeper understanding of the transient characteristics of arc breakdow
Replenishing IRAK-M expression in retinal pigment epithelium attenuates outer retinal degeneration
Chronic inflammation is a constitutive component of many age-related diseases, including age-related macular degeneration (AMD). Here, we identified interleukin-1 receptor-associated kinase M (IRAK-M) as a key immunoregulator in retinal pigment epithelium (RPE) that declines during the aging process. Rare genetic variants of IRAK3, which encodes IRAK-M, were associated with an increased likelihood of developing AMD. In human samples and mouse models, IRAK-M abundance in the RPE declined with advancing age or exposure to oxidative stress and was further reduced in AMD. Irak3-knockout mice exhibited an increased incidence of outer retinal degeneration at earlier ages, which was further exacerbated by oxidative stressors. The absence of IRAK-M led to a disruption in RPE cell homeostasis, characterized by compromised mitochondrial function, cellular senescence, and aberrant cytokine production. IRAK-M overexpression protected RPE cells against oxidative or immune stressors. Subretinal delivery of adeno-associated virus (AAV)-expressing human IRAK3 rescued light-induced outer retinal degeneration in wild-type mice and attenuated age-related spontaneous retinal degeneration in Irak3-knockout mice. Our data show that replenishment of IRAK-M in the RPE may redress dysregulated pro-inflammatory processes in AMD, suggesting a potential treatment for retinal degeneration
Paleokarst crust of Ordovician limestone and its capability in resisting water inrushes in coal mines of north China NCKRI Symposium 2: Proceedings of the Thirteenth Multidisciplinary Conference on Sinkholes and the Engineering and Environmental Impacts of Karst
Karst Paleo-Collapses and Their Impacts on Mining and the Environment in Northern China
Karst paleo-collapses are unique collapse structures widely found in the coal measures of northern China. Their geometric dimensions and internal properties indicate that a compound dissolution of carbonate and gypsum rocks may contribute to their formation. When these collapses are permeable to groundwater flow, they hydraulically connect the coal seams and the karst aquifers, which is a pre-requisite for water inrushes during coal mining. Over the last 40 years, water inrushes through these collapses have caused fatalities, economic losses, and degradation in the environment in northern China. Determination of locations and hydrogeological characteristics of the karst paleo-collapses are essential in preventing water inrush incidents through them. Advanced geophysical prospecting, aquifer testing and accompanied dye tracing are effective approaches to investigating these structures
Karst Paleo-Collapses and Their Impacts on Mining and the Environment in Northern China
Karst paleo-collapses are unique collapse structures widely found in the coal measures of northern China. Their geometric dimensions and internal properties indicate that a compound dissolution of carbonate and gypsum rocks may contribute to their formation. When these collapses are permeable to groundwater flow, they hydraulically connect the coal seams and the karst aquifers, which is a pre-requisite for water inrushes during coal mining. Over the last 40 years, water inrushes through these collapses have caused fatalities, economic losses, and degradation in the environment in northern China. Determination of locations and hydrogeological characteristics of the karst paleo-collapses are essential in preventing water inrush incidents through them. Advanced geophysical prospecting, aquifer testing and accompanied dye tracing are effective approaches to investigating these structures
Paleokarst Crust of Ordovician Limestone and Its Capability in Resisting Water Inrushes in Coal Mines of North China
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