Numerical Simulation of Uniaxial Compressive Strength and Failure Characteristics of Non-Uniform Water-Bearing Sandstone.

As complex and heterogeneous materials, the mechanical properties of rocks are still in need of further investigation regarding the mechanisms of the effects of water. In engineering projects such as goaf foundation treatment and ecological restoration, it is particularly important to describe the fracturing process of non-uniform water-containing sandstone media. The study utilized the theory of continuum mechanics to adopt an elastoplastic strain-softening constitutive relationship and develop a numerical model for analyzing the uniaxial compressive strength and failure characteristics of non-uniform water-containing sandstone. The results indicate that, compared with the reference rock sample, the shorter the capillary path of water entering the rock sample's internal pores or the larger the contact area with water, the shorter the time required for the rock sample to be saturated. Increasing the water content causes a rapid decline in the rock sample's elastic modulus and intensifies its brittleness. Group D2 and D3 samples exhibited a decrease in average peak strength to 70.4% and 62.1%, respectively, along with a corresponding decrease in the elastic modulus to 90.78% and 76.55%, indicating significant strain softening. While the failure mode of the rock sample remains consistent across different water contents, the homogeneity of failure shows significant variation. Increasing volumetric water content raises the likelihood of interconnecting cracks between rock samples, resulting in a progressive decline in macroscopic mechanical properties such as peak strength, critical strain, and elastic modulus. This research is significant in advancing the theory and construction technology for ecological restoration in goaf areas.

The impact of environmental regulation on regional economic growth: A case study of the Yangtze River Economic Belt, China.

In this paper, we take the Yangtze River Economic Belt as the study area and analyze three types of environmental regulation tools, namely, command-and-control (CAC), market-incentivized (MI) and public-type (PT). We apply the threshold effect to test the impact of each of these tools on regional economic growth and analyze the relationships between the tools and environmental regulation. The entropy method is used to calculate the comprehensive environmental pollution index of each province and city in the Yangtze River Economic Belt. Using Stata 14.0 measurement software and based on provincial data with respect to the Yangtze River Economic Belt from 2014 to 2021, a panel threshold model is used to test the impact of the three types of environmental regulation tools on regional economic growth and analyze the relationship between environmental regulation and regional economic growth. It is found that the relationship between environmental regulation and economic growth is non-linear. There is no significant relationship between CAC environmental regulation and regional economic growth; there is a single threshold effect between market-incentive environmental regulation and public participation environmental regulation on the economic growth of the Yangtze River economic belt.

Differences in Dietary and Lifestyle Triggers between Non-Erosive Reflux Disease and Reflux Esophagitis-A Multicenter Cross-Sectional Survey in China.

The occurrence of gastroesophageal reflux disease (GERD) and symptom onset are closely associated with diet. We aimed to compare the dietary and lifestyle triggers between non-erosive reflux disease (NERD) and reflux esophagitis (RE) in Chinese patients and to provide evidence for development of practical dietary modifications for GERD. A multicenter cross-sectional survey was conducted. A total of 396 GERD patients with typical gastroesophageal reflux symptoms who received upper endoscopy in the previous month were enrolled, including 203 cases of NERD patients and 193 cases of RE patients. All participants completed questionnaires including demographic data, reflux symptoms, previous management, dietary and lifestyle habits, triggers of reflux symptoms, psychological status, and quality of life. There were no significant differences in GERD symptom scores between NERD and RE. RE patients had a higher male proportion and smoking/drinking and overeating rates than NERD patients. In the NERD group, more patients reported that fruits, dairy products, yogurt, bean products, cold food, and carbonated beverages sometimes and often induced reflux symptoms and had more triggers compared to RE patients. The number of triggers was positively correlated to GERD symptom score and GERD-HRQL score in both NERD and RE patients. However, 74.0% of GERD patients still often consumed the triggering foods, even those foods that sometimes and often induced their reflux symptoms, which might be related to the reflux relapse after PPI withdrawal considering NERD and RE patients had similar GERD symptom severity. There were some differences in terms of dietary habits, dietary and lifestyle triggers, and related quality of life between NERD and RE, and these results may provide evidence of different approaches toward the dietary modification of NERD and RE patients.

The mechanism of chlorogenic acid inhibits lipid oxidation: An investigation using multi-spectroscopic methods and molecular docking.

Endogenous lipase and lipoxygenase play important roles in accelerating lipid oxidation. Polyphenols are a series of commonly used chemicals for preserving fish and seafood products, due to their positive inhibitory effects on lipid oxidation. However, the mechanism involved is still unknown. The inhibitory effects of chlorogenic acid (CGA) on lipase and lipoxygenase were investigated and explored with multi- spectroscopic and molecular docking approaches. Results showed that CGA could inhibit the activities of lipase and lipoxygenase with concentration increased in a highly dose-dependent manner. CGA quenched intrinsic fluorescence intensities of enzymes by static quenching and binding with CGA which led to changes in 3D structures of enzymes. Results of the molecular docking confirmed binding modes, binding sites and major interaction forces between CGA and enzymes, which reduced the corresponding activity. Thus, this study could provide basic mechanisms of the inhibitory effects of polyphenols on lipid oxidation during food preservation.

Improving understanding of carbon stock characteristics of Eucalyptus and Acacia trees in southern China through litter layer and woody debris.

Surveying the quality and quantity of carbon stock in litter layer and woody debris of Eucalyptus and Acacia plantations is critical in understanding their carbon pools. Here, the focus of the present study was on a number of Eucalyptus and Acacia plantations of different stand aged in the Pearl River Delta region of southern China. The plantation type proved to be a crucial driver of the carbon concentration in litter layer and woody debris, with Acacia exhibiting a superior ability to Eucalyptus to accumulate carbon with stand age in both these materials. The relative contribution of the litter layer and woody debris to the carbon stock of the ecosystem was also significantly higher under mature Acacia (8% and 7%, respectively) than that under mature Eucalyptus (4% and 1%, respectively). Most of the carbon stock within the litter layer was present in the leaf debris. The carbon stock in woody debris was mainly contained in the components within the 10-20 cm diameter class during the primary decay stage, represented as snags in middle-aged and mature Acacia, and as logs for mature Eucalyptus, respectively. The results indicate that both plantation type and stand age influence the characteristics of carbon stored in litter layer and woody debris significantly.

Characterization of household food waste and strategies for its reduction: A Shenzhen City case study.

A clear understanding of the characteristics of generated household food waste (HFW) is necessary to formulate an effective food waste management policy. The present study has focused on the quantity and composition of generated HFW as well as the driving forces, and further explored potential means of reducing HFW. The quantity of avoidable HFW generated in Shenzhen City in 2015 was estimated to be two-fold greater than that in 2001, which consequently produced 1,378 thousand metric tonnes CO2 eq. emissions during their ultimate waste disposal. This suggests that HFW prevention can yield great environment benefits by reducing carbon emissions. Based on a survey in which 418 households in Shenzhen City participated, it was apparent that both household size and income are the major drivers to HFW generation. A substantial reduction in HFW generation can be achieved through improvements in consumer behaviors, consciousness and attitudes. Priority should be given to the strategies that can increase people's awareness of HFW induced problems, with the purposes to achieve a more sustainable development.

Criteria for assessing the ecological risk of nonylphenol for aquatic life in Chinese surface fresh water.

The typical environmental endocrine disruptor nonylphenol is becoming an increasingly common pollutant in both fresh and salt water; it compromises the growth and development of many aquatic organisms. As yet, water quality criteria with respect to nonylphenol pollution have not been established in China. Here, the predicted "no effect concentration" of nonylphenol was derived from an analysis of species sensitivity distribution covering a range of species mainly native to China, as a means of quantifying the ecological risk of nonylphenol in surface fresh water. The resulting model, based on the log-logistic distribution, proved to be robust; the minimum sample sizes required for generating a stable estimate of HC5 were 12 for acute toxicity and 13 for chronic toxicity. The criteria maximum concentration and criteria continuous concentration were, respectively 18.49 µg L-1 and 1.85 µg L-1. Among the 24 sites surveyed, two were associated with a high ecological risk (risk quotient >1) and 12 with a moderate ecological risk (risk quotient >0.1). The potentially affected fraction ranged from 0.008% to 24.600%. The analysis provides a theoretical basis for both short- and long-term risk assessments with respect to nonylphenol, and also a means to quantify the risk to aquatic ecosystems.

Enzymic degradation of hydroxyethyl cellulose and analysis of the substitution pattern along the polysaccharide chain.

The enzymatic degradation behavior of hydroxyethyl cellulose (HEC) samples with different molar substitutions (MS) values was investigated. The changes in the molecular structure of HEC treated with enzymatic approach in comparison to the native HEC were studied through nuclear magnetic resonance (NMR), fourier transform infrared spectra (FTIR), X-ray diffraction (XRD) and scanning electron microscopy (SEM) techniques and kinetics of degradation was studied by viscometry. The cleavage of HEC chains could be observed from FTIR and kinetics results. Moreover, reduce in molecular weight (Mw) of polymer and liberated glucose concentration was investigated by gel permeation chromatography (GPC) analysis during enzymatic degradation. And all these results indicated that HEC with lower MS is more susceptible to degrade and provided a better understanding of the mechanism operating during enzymatic hydrolysis of HEC by cellulases. Furthermore, by complete degradation and quantification of liberated glucose, the substitution index (SI) and the distribution of substituents along the HEC chain were investigated. The results suggested that the HEC samples differed in hydroxyethyl molar substitutions (MS) and possible distribution of the hydroxyethyl groups. Impressively, our efforts established a facile analytical method for the elucidation of the distribution of substituents along the HEC chain.

Characterization of post-disaster environmental management for Hazardous Materials Incidents: Lessons learnt from the Tianjin warehouse explosion, China.

Hazardous Materials Incidents (HMIs) have attracted a growing public concern worldwide. The health risks and environmental implications associated with HMIs are almost invariably severe, and underscore the urgency for sound management. Hazardous Materials Explosion incidents (HMEIs) belong to a category of extremely serious HMIs. Existing studies placed focuses predominately on the promptness and efficiency of emergency responses to HMIs and HMEIs. By contrast, post-disaster environmental management has been largely overlooked. Very few studies attempted to examine the post-disaster environmental management plan particularly its effectiveness and sufficiency. In the event of the Tianjin warehouse explosion (TWE), apart from the immediate emergency response, the post-disaster environmental management systems (P-EMSs) have been reported to be effective and sufficient in dealing with the environmental concerns. Therefore, this study aims to critically investigate the P-EMSs for the TWE, and consequently to propose a framework and procedures for P-EMSs in general for HMIs, particularly for HMEIs. These findings provide a useful reference to develop P-EMSs for HMIs in the future, not only in China but also other countries.

Multivariate assessment of polycyclic aromatic hydrocarbons in surface sediments of the Beijiang, a tributary of the Pearl River in Southern China.

To estimate the severity of polycyclic aromatic hydrocarbon (PAH) contamination in the upper sediment of the Beijiang River, 42 sediment samples were analyzed for the presence of 16 key PAHs using gas chromatography-mass spectrometry. The concentrations of PAH in the sediment ranged from 44 to 8,921 ng g(-1) dry weight. The four- to six-ring PAHs, contributing >50% to PAHs in 34 of the 42 sites, were the dominant species. Based on a principal component analysis, combined with multivariate linear regression, it became clear that the most important contributors of PAH were fossil fuel combustion (48%), diesel emissions plus oil spillage (33%), and coke combustion (19%). The surface sediments of Beijiang River were grossly contaminated by PAHs mainly derived from combustion.