Dynamic Behavior of Viscous Droplets Impact on a Flexible Mesh Surface.

The dynamic behavior of a viscous droplet impacting a flexible mesh surface with a fixed end is studied by high-speed photography in this work. Our experimental results reveal that surface vibration occurs when the viscous droplet impacts the flexible mesh surface. Simultaneously, the droplet spreads on the upper surface and penetrates into the mesh surface, resulting in a decrease in the spreading diameter on the upper surface. On the lower surface, the droplet elongates and forms multiple ligaments. Notably, different dynamic behaviors are observed when the droplet impacts surfaces with varying Weber (We) numbers due to viscous dissipation and surface vibration. However, as the impact position deviates from the fixed end, the surface vibrational amplitude increases, leading to a decreased diffusion range of the droplet on the lower surface. In addition, the vibration amplitude significantly enhances with increase of the We number. The vibration induces stretching and eventual rupture of the cardinal ligament under specific conditions. The first breaking time of the cardinal ligament delays with the decrease of the We number. As the impact position moves away from the fixed end, this situation is enhanced. Especially, when the stretching direction of the ligament is inconsistent with the vibration direction of the surface, the vibration has a great influence on the stretching behavior of the cardinal ligament.

DDIT3/CHOP promotes LPS/ATP-induced pyroptosis in osteoblasts via mitophagy inhibition.

Inflammatory environments can trigger endoplasmic reticulum (ER) stress and lead to pyroptosis in various tissues and cells, including liver, brain, and immune cells. As a key factor of ER stress, DNA damage-inducible transcript 3 (DDIT3)/CCAAT/enhancer-binding protein (C/EBP) homologous protein (CHOP) is upregulated in osteoblasts during inflammatory stimulation. DDIT3/CHOP may therefore regulate osteoblast pyroptosis in inflammatory conditions. During this investigation, we found that lipopolysaccharides (LPS)/adenosine 5'-triphosphate (ATP) stimulation in vitro induced osteoblasts to undergo pyroptosis, and the expression of DDIT3/CHOP was increased during this process. The overexpression of DDIT3/CHOP further promoted osteoblast pyroptosis as evidenced by the increased expression of the inflammasome NLR family pyrin domain containing 3 (NLRP3) and ratios of caspase-1 p20/caspase-1 and cleaved gasdermin D (GSDMD)/GSDMD. To explore the specific mechanism of this effect, we found through fluorescence imaging and Western blot analysis that LPS/ATP stimulation promoted PTEN-induced kinase 1 (PINK1)/E3 ubiquitin-protein ligase parkin (Parkin)-mediated mitophagy in osteoblasts, and this alteration was suppressed by the DDIT3/CHOP overexpression, resulting in increased ratio of pyroptosis compared with the control groups. The impact of DDIT3/CHOP on pyroptosis in osteoblasts was reversed by the application of carbonyl cyanide 3-chlorophenylhydrazone (CCCP), a specific mitophagy agonist. Therefore, our data demonstrated that DDIT3/CHOP promotes osteoblast pyroptosis by inhibiting PINK1/Parkin-mediated mitophagy in an inflammatory environment.

PTX3 promotes cementum formation and cementoblast differentiation via HA/ITGB1/FAK/YAP1 signaling pathway.

Cementum is a vital component of periodontium, yet its regeneration remains a challenge. Pentraxin 3 (PTX3) is a multifunctional glycoprotein involved in extracellular matrix remodeling and bone metabolism regulation. However, the role of PTX3 in cementum formation and cementoblast differentiation has not been elucidated. In this study, we initially observed an increase in PTX3 expression during cementum formation and cementoblast differentiation. Then, overexpression of PTX3 significantly enhanced the differentiation ability of cementoblasts. While conversely, PTX3 knockdown exerted an inhibitory effect. Moreover, in Ptx3-deficient mice, we found that cementum formation was hampered. Furthermore, we confirmed the presence of PTX3 within the hyaluronan (HA) matrix, thereby activating the ITGB1/FAK/YAP1 signaling pathway. Notably, inhibiting any component of this signaling pathway partially reduced the ability of PTX3 to promote cementoblast differentiation. In conclusion, our study indicated that PTX3 promotes cementum formation and cementoblast differentiation, which is partially dependent on the HA/ITGB1/FAK/YAP1 signaling pathway. This research will contribute to our understanding of cementum regeneration after destruction.

Influencing factors and prediction of net carbon sink in the primary sector of the coastal city in China.

To achieve the goal of urban carbon dioxide emission reduction, how to increase carbon sequestration has become a top priority. The biological sink is mainly divided into green carbon sink and blue carbon sink. Coastal cities have two kinds of carbon sinks. There, the study of carbon sinks in coastal cities is the primary choice to cope with climate change. Therefore, this study chooses coastal cities with primary industries including agriculture, fishery, and forestry as the study subjects. The LMDI (Log-Mean Divisia Index) method and multiple regression prediction models were used to explore the low-carbon countermeasures which increase urban net carbon sink from the perspective of influencing factors and future potential. The study found that the average output value of employees in the primary industry is the main driving factor, and the change in the purchasing power of unit carbon sinks and the change in the proportion of employees in the primary industry have inhibited the increase in net carbon sinks. Projections based on the primary industry's output and afforestation area as independent variables show an overall upward trend in net carbon sinks, reaching 15.70 million tons of net carbon sinks in 2060, offsetting 10-20% of total carbon emissions in the same year. Based on the calculation results, this paper puts forward some corresponding countermeasures to increase carbon sinks. This paper provides a theoretical reference for the low-carbon development of coastal cities in China, and the strategies can be also expanded to other cities with similar resources around the world.

Analysis on shadow price and abatement potential of carbon dioxide in China's provincial industrial sectors.

CO2 emission performance evaluation is crucial to make abatement policies. Knowledge about the potential and costs of CO2 reduction could provide information guides for policymakers and help them implement targeted measures. However, relevant studies are rarely subdivided into detailed industrial sectors, and results are lack of inter-industry comparisons. To fill this gap, this study estimates provincial technical inefficiency, abatement potential, and shadow price of CO2 from fuel combustion in China's 25 industries in 2001-2017. Results show that China's industry could ideally reduce CO2 emissions by a further 22.01-33.27%, averaging 1645.96 MtCO2. Technical efficiency, abatement potential, and cost vary across provinces and industries and should therefore be fully considered when designing emission reduction targets and control policies. Provinces and industries with low technical efficiency, large-scale emissions, great abatement potential and low shadow price are the key to emission reduction. We thus identify key provinces and industries that need to take on more abatement responsibility. Those findings are of great significance to the formulation of carbon reduction targets and the implementation of abatement policies, and prove the feasibility of China's trans-regional carbon trading. It is suggested to prioritize key industries into the trading system and further promote inter-provincial cooperation through carbon trading.

Natural resources, population aging, and environmental quality: analyzing the role of green technologies.

Depletion of natural resources and population aging are the two most critical challenges for environmental sustainability. However, the research that integrates natural resources and population aging in the same environmental policy framework is still scant. Therefore, this study investigates the linkage between natural resources, population aging, green technologies, and ecological footprint (EF) of G7 countries. In addition, this study also explores the moderating effects of green technologies on the relationship between natural resources and EF. Drawing on the panel times series data from 1970 to 2017, we employ a cross-sectional autoregressive distributed lags (CS-ARDL) model for short- and long-run empirical estimation. Our empirical analysis indicates that natural resource use exacerbates ecological degradation by increasing EF. By contrast, population aging and green technologies present positive ameliorative effects on EF. Interestingly, the interaction effect of green technologies and natural resources indicates that the damage to ecological quality from natural resources can be effectively improved by means of green technologies, thus maintaining environmental sustainability. Furthermore, the results of panel quantile regression show that the effects of population aging and green technologies on the overall ecological footprint distribution in G7 countries are heterogeneous, while the effects of natural resources on the distribution of all conditions of the ecological footprint are positive. In addition, this paper verifies the causal relationship between the variables using the Dumitrescu and Hurlin test. The findings reveal that the relevant changes in all explanatory variables are bilaterally causally associated with EF. Based on these results, this paper provides some feasible policy recommendations.

Study on the spatial interaction between carbon emission intensity and shadow economy in China.

Both high carbon emission intensity (CEI) and large scale of shadow economy in China are the undesirable products of economic development with too fast growth rate. For the rapid and healthy development of the economy in China, the research on the relationship between the two should attract more attention, while the relevant literatures are very few at present. According to the panel data of 30 provinces in China from 2004 to 2016, this paper firstly examines the spatial correlation between CEI and the scale of shadow economic. Then verifies the interaction relationship between them with SPDM (spatial panel Dubin Model). Moreover, the robustness test is conducted with three different spatial weight matrices. As the interaction between CEI and shadow economy has been proved, providing new ideas for carbon emission reduction, environmental protection, and healthy economic development with rapid rate in the future. The specific conclusions are as follows: first, CEI and shadow economy both have significant positive spatial autocorrelation. Second, there is a spatial interaction between CEI and shadow economy, indicating provincial cooperation plays a very important role in both economic growth and environment protection. Third, the impacts from economic development on both CEI and shadow economy satisfy the EKC hypothesis. Also, the development of the tertiary industry plays a positive role in promoting the growth of CEI, while promotes and inhibits the expansion of shadow economic scale at the same time.

Study on the impact of comprehensive urbanization on urban civil building CO2 emissions in China.

With the rapid development of China, urbanization has become an important research topic of China's CO2 emissions. To fill the gap in considering the spatial correlation of the comprehensive urbanization that includes multi-dimensional factors on CO2 emissions from urban civil buildings (UBEC), this study constructs a comprehensive evaluation indicator of urbanization from four aspects including population, economy, society, and land urbanization by using the entropy method. The spatial spillover effect of UBEC and the impact of comprehensive urbanization on UBEC are also studied by using the spatial panel model in this paper. This study finds out that UBEC has obvious spatial spillover effects. During the early years of the study period, the eastern coastal areas had greater carbon emissions, while in recent years, they have gradually transitioned to the northwestern regions. Comprehensive urbanization has a significant promotion effect on it. And foreign direct investment and per capita energy consumption also have positive impact on UBEC. This study provides a reference for measuring the effects of urbanization on sector-specific CO2 emissions and may be useful for energy efficiency and emission abatement efforts in China.

Convergence study of water pollution emission intensity in China: evidence from spatial effects.

One of the challenges that China currently faces is how to reduce the emissions of water pollution. However, the study of water pollution convergence has a certain policy significance for controlling the emissions of water pollution. This article firstly uses chemical oxygen demand (COD) and ammonia nitrogen (NH3-N) as indicators of water pollution. Due to the obvious spillover effect of water in space, this article adds a spatial effect to the convergence model. Based on panel data of 30 provinces and cities from 2006 to 2017, this article uses a dynamic spatial Dubin model to analyze the convergence of water pollution emission intensity to address the endogenous problem in the model. The empirical results of this paper show that there is absolute ß-convergence and conditional ß-convergence in the intensity of water pollution emissions. The spatial autocorrelation test shows that there is a positive spatial autocorrelation of water pollution emissions, which means that the pollution emissions in neighboring areas will affect the emissions in the local area. The industrial structure has a certain promoting effect on the emission of water pollution, which means that adjusting the industrial structure and alleviating the structure of the secondary industry is the trend of future development. Economic growth can curb the emissions of water pollution. The influences of urbanization and foreign investment on the emissions of the two pollutants are inconsistent, and policies can be formulated according to local conditions in the future.

Random-walk model simulation of air pollutant dispersion in atmospheric boundary layer in China.

In this study, the land-sea breeze circulation model coupled with a random-walk model is developed by the analysis of the formation and the mechanism of the land-sea breeze. Based on the data of the land-sea circulation in Dalian, China, the model simulated the diurnal variation of pressure, flow, temperature, and turbulent kinetic energy field and also provides a basis for solving the air pollutant concentration in the land-sea breeze circulation so as to estimate the economic cost attributable to the atmospheric pollution. The air pollutant concentration in the background of land-sea circulation is also simulated by a Gaussian dispersion model, and the results revealed that the land-sea circulation model coupled with the random-walk model gives a reasonable description of air pollutant dispersion in coastal areas.

Convergence analysis of regional marginal abatement cost of carbon dioxide in China based on spatial panel data models.

China has announced to launch a national emission trading system (ETS). The heterogeneity of marginal abatement cost (MAC) is prerequisite for trading, and the knowledge about the evolutionary characteristics of MAC is particularly necessary. However, the ß convergence theory has been proved to be suitable yet rarely applied to the study of MAC of CO2. To fill this gap, this paper connects them creatively, and the convergence of MAC during 2001-2015 and the influential factors are explored by spatial panel data models. Results show that China's MAC converges during the study period whether the spatial effect is considered or not. When evaluating the convergence of MAC, the spatial effect should not be ignored, because it will improve the explanatory power of models and promote the convergence. The size of labor force, emission level, coal consumption, foreign direct investment, and industrial structure significantly affect the growth rate of MAC. Low-carbon policies could be formulated fully considering the factors and their spillover effects. Those findings are certainly significant in imposing carbon reduction targets and adopting policy instruments. In addition, a national ETS is more applicable to China's reality at this stage and suggested to introduce carbon tax in due course in the future.

Study on the long-term impact of economic globalization and population aging on CO2 emissions in OECD countries.

Both economic globalization and population aging have given rise to changes in environmental quality, but the research that integrates these two crucial factors into the same environment policy framework is still a blank. Therefore, using panel data of the Organization for Economic Cooperation and Development (OECD) over the period 1971-2016, this study examines the long-term impact of economic globalization and population aging on CO2 emissions. First, second-generation panel regression approaches are employed to verify the panel data, including unit root tests, cointegration tests and causality tests. Next, Fully Modified Ordinary Least Squares (FMOLS) and Dynamic Ordinary Least Squares (DOLS) are respectively used for empirical analysis of the long-term impact between variables. The augmented mean group (AMG) is also applied to ascertain the robustness results of the estimation coefficients. Finally, using Dumitrescu and Hurlin non-causality test to examine the causal associations between variables to avoid the contingency of the results. The overall results show that economic globalization and population aging decrease the long-term CO2 emissions. The inverted U-shaped relationship between economic growth and environmental pollution confirms the effectiveness of the Environmental Kuznets Curve (EKC) in OECD countries. In addition, unidirectional causal relationships have been found from economic globalization and population aging to CO2 emissions in this study. Policy suggestions in response to these findings are discussed.

Environmental tradeoffs in municipal wastewater treatment plant upgrade: a life cycle perspective.

Municipal wastewater treatment plants (WWTPs) play an indispensable role in improving environmental water quality in urban areas. Existing WWTPs, however, are an important source of greenhouse gas (GHG) emissions and may not be able to treat increasingly complicated wastewater or meet stringent environmental standards. These WWTPs can be updated to address these challenges, and different technologies are available but with potentially different environmental implications. Life cycle assessment (LCA) is a widely used approach to identify alternatives with lower environmental footprint. In this study, LCA was applied to an actual urban WWTP, considering four scenarios involving upgrading and energy-resource recovery. The environmental performance with respect to life cycle GHG emissions and eutrophication impact was analyzed. The environmental benefits of reduced water pollution and energy and material displacement associated with energy-resource recovery process were also considered. The results showed tradeoffs among the four scenarios. Although upgrading the studied WWTP would meet discharge standard for total phosphorus and reduce total eutrophication impact by about 19%, it would increase GHG emissions by at least 16%. Besides, the energy-resource recovery mode for existing WWTP (S2) performs the best in terms of GHG emissions. For different biogas utilization methods, combined heat and power (CHP) system is superior to the existing method of delivering biogas to gas grid, in terms of energy recovery or reduction of GHG emissions and eutrophication impact. Our research results may provide a reference for plant managers to select the most environmentally friendly upgrade scheme and energy-resource recovery technique for future upgrade projects.

Interaction between shadow economy and pollution: empirical analysis based on panel data of northeast China.

Side issues of economy development break out in China during recent decades, like environmental pollution or the widely ignored one, shadow economy. Using annual data for the three provinces at northeast China over the period 2000 to 2016, this paper examines the size of the shadow economy by MIMIC model first and then adopts the dynamic panel analysis to study the direct relationship between the shadow economy and pollution level. The major innovation point of this paper is the pioneering study of the impact from the pollution level on the size of shadow economy. We also employ various pollution descriptions from terrestrial, aquatic, and atmospheric ecosystems as the robustness check to make our following conclusions more comprehensive and credible: (1) shadow economy is a direct quality factor to the increase of the pollution level. (2) A positive effect from pollution to shadow economy also exists: the higher the pollution level is, the larger the size of shadow economy will be. In the end, this paper proposes several valuable information and suggestions to the government in economy development and pollution abatement.

Experimental study of the supercritical CO2 diffusion coefficient in porous media under reservoir conditions.

Reliable measurement of the CO2 diffusion coefficient in consolidated oil-saturated porous media is critical for the design and performance of CO2-enhanced oil recovery (EOR) and carbon capture and storage (CCS) projects. A thorough experimental investigation of the supercritical CO2 diffusion in n-decane-saturated Berea cores with permeabilities of 50 and 100 mD was conducted in this study at elevated pressure (10-25 MPa) and temperature (333.15-373.15 K), which simulated actual reservoir conditions. The supercritical CO2 diffusion coefficients in the Berea cores were calculated by a model appropriate for diffusion in porous media based on Fick's Law. The results show that the supercritical CO2 diffusion coefficient increases as the pressure, temperature and permeability increase. The supercritical CO2 diffusion coefficient first increases slowly at 10 MPa and then grows significantly with increasing pressure. The impact of the pressure decreases at elevated temperature. The effect of permeability remains steady despite the temperature change during the experiments. The effect of gas state and porous media on the supercritical CO2 diffusion coefficient was further discussed by comparing the results of this study with previous study. Based on the experimental results, an empirical correlation for supercritical CO2 diffusion coefficient in n-decane-saturated porous media was developed. The experimental results contribute to the study of supercritical CO2 diffusion in compact porous media.