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Research on the spatiotemporal coupling relationships between land use/land cover compositions or patterns and the surface urban heat island effect 全文
2022
Ma, Xiaoliang | Peng, Shuangyun
Urbanization leads to changes in landscape configuration and land use/land cover (LULC) patterns, and these changes are important factors affecting the surface urban heat island (SUHI) effect. However, from the perspective of spatiotemporal changes, quantitative analytical results regarding the impacts of the LULC composition, configuration, and pattern in inland plateau lakeside cities on the SUHI effect, and the responsive relationships among these factors remain unclear. By combining satellite remote sensing data with analytical methods, such as urban–rural gradients, spatial statistics, and landscape pattern indices, the impacts of LULC changes on the SUHI effect in Kunming, China, are revealed. The results show the following. (1) The explosive growth in impervious surfaces (ISs) caused by urbanization, leading to changes in the LULC composition, configuration and pattern, is the main reason for the deterioration of the SUHI effect. Over the past 30 years, Kunming’s ISs have increased by 304.58 km², SUHI has expanded by 764.26 km², and the regional average land surface temperature (LST) has increased by 1 °C. (2) This study also found that a large area of bare ground is another important reason for the sharp rise in LST, explaining why bare land (BL) has the highest average LST (28.72 °C). (3) The pattern of LULC can well explain the spatial distribution characteristics of SUHIs. The normalized difference built-up index (NDBI), normalized difference bareness index (NDBaI), and LST have the same change curve along the urban–rural gradient, while the normalized difference vegetation index (NDVI), modified normalized difference water index (MNDWI), and LST have opposite trends. (4) ISs and water body (WB) are the main types of warming and cooling, respectively, but the warming effect of ISs is greater than the cooling effect of WB. From the average value of the correlation coefficient with LST, NDBI (0.84) > MNDWI (-0.63). (5) Kunming’s remote sensing index values do not have simple linear relationships with the LST. NDBaI, NDBI, and LST show significant exponential relationships, and NDVI, MNDWI, and LST show significant quadratic polynomial relationships. (6) The dominant landscape type determines the correlation between the landscape shape index (LSI) and the LST of green spaces (GSs). (7) Adopting a simple and regular landscape layout can effectively reduce the SUHI effect. These research results could provide a scientific decision-making basis for the spatial urban planning and ecological construction of Kunming and could have practical significance for guiding the green, healthy, and sustainable development of the city.
显示更多 [+] 显示较少 [-]The average environmental efficiency technique and its application to Chinese provincial panel data 全文
2022
Tang, Jing | Yang, Feng | Wei, Fangqing
In this study, we propose average environmental efficiency, a more comprehensive, fair, comparable, and robust environmental efficiency measurement considering all projection directions to the efficient frontier, and then it is used to evaluate the environmental efficiency of Chinese provinces from 2006 to 2017. Furthermore, we investigate the most influential factors of regional environmental efficiency via a feasible generalized least squares regression approach. The empirical results show that only nine Chinese provinces have average environmental efficiency greater than the national average, implying that two-thirds of the provinces still have much room for improvement. Additionally, environmental efficiency disparities exist between provinces and between four larger geographical areas. The east area achieved the best environmental efficiency over the studied period, better than the whole country, followed in order by the west area, central area, and northeast area. Moreover, we find that the energy consumption structure, government intervention, and economic openness significantly and negatively influence regional environmental efficiency. Finally, we provide policy implications in terms of energy consumption structure optimization, government supervision, and foreign investment introduction while considering the local conditions in different provinces.
显示更多 [+] 显示较少 [-]Simultaneous removal of gaseous benzene and toluene with photocatalytic oxidation process at high temperatures under UVC irradiation 全文
2022
Dursun, Şükrü | Ayturan, Zeynep Cansu
Organic air pollutants represent many different pollutants, including persistent toxic organics and volatile organic compounds (VOC). The VOC group includes about 150 different compounds, the majority of which are considered harmful and toxic to human health. Considering all these features, the removal of VOC is of great importance. According to the Industrial Air Pollution Control Regulation, VOCs in flue gases are classified, and the limit value for the most dangerous group is specified as 20 mg/m³ according to the degree of damage. From past to present, many different removal technologies have been developed and continue to be developed. Removal of pollutants at low concentrations by conventional methods is more inadequate than those above certain concentrations. Photocatalytic oxidation (PCO) is one of the technologies used for VOC removal recently. It has been determined that many different organic pollutants can be removed with this method. Within the scope of this study, the removal of benzene and toluene pollutants, which are two important VOCs frequently encountered in flue gases, by the photocatalytic oxidation method has been studied under UVC irradiation. In this study, a new photocatalyst by doping silver (Ag), a noble metal, and nickel (Ni), one of the transition metals, on TiO₂ nanoparticles was developed and a laboratory-scale reactor system was designed. Many experiments were carried out by changing the system parameters such as ambient temperature (120 °C, 150 °C, 180 °C), humidity (25% and 50%), and percentage of Ag and Ni doping on TiO₂ (0.5%, 1%, 2.5%, %5) and the most successful conditions for the removal of benzene and toluene contaminants were tried to be determined based on the results obtained. When all experiments carried out within the scope of this study were considered, the average removal efficiency for benzene was found as 89.33%, while the average removal efficiency for toluene was 88.23%. According to the obtained results, the most suitable conditions for the simultaneous removal of benzene and toluene pollutants with photocatalytic oxidation method under UVC light were determined as 120 °C temperature, 25% humidity, and 0.5% doping photocatalyst.
显示更多 [+] 显示较少 [-]Effective mitigation of single-component and mixed textile dyes from aqueous media using recyclable graphene-based nanocomposite 全文
2022
Tran, Thuan Van | N. Vo, Dai-Viet | Nguyen, Duyen Thi Cam | Ching, Yern Chee | Nguyen, Ngoc Tung | Nguyễn, Quang Trung
The present study reported the synthesis and utilization of a graphene-based hybrid nanocomposite (MnFe₂O₄/G) to mitigate several synthetic dyes, including methylene blue, malachite green, crystal violet, and Rhodamine B. This adsorbent was structurally analyzed by several physicochemical techniques such as X-ray diffraction, Fourier-transform infrared spectroscopy, scanning electron microscopy, Raman spectroscopy, N₂ adsorption–desorption isotherm measurement, point of zero charge, and Boehm titrations. BET surface area of MnFe₂O₄/G was measured at 382.98 m²/g, which was substantially higher than that of MnFe₂O₄. MnFe₂O₄/G possessed diverse surface chemistry properties with the presence of many functional groups such as carboxylic acid, phenolic, lactone, and basic groups. MnFe₂O₄/G was used to remove synthetic dyes in the aqueous media. The effect of many factors, e.g., concentration (5–50 mg/L), pH (4–10), dose (5–20 mg), and temperature (25–45 °C) on adsorption performance of MnFe₂O₄/G was conducted. Kinetic, isotherm, intraparticle, and thermodynamic models were adopted for investigating adsorption phenomenon of dyes on MnFe₂O₄/G. The maximum adsorption capacity of dyes over MnFe₂O₄/G was found as Rhodamine B (67.8 mg/g) < crystal violet (81.3 mg/g) < methylene blue (137.7 mg/g) < malachite green (394.5 mg/g). Some tests were performed to remove mixed dyes, and mixed dyes in the presence of antibiotics with total efficiencies of 65.8–87.9% after 120 min. Moreover, the major role of π–π stacking interaction was clarified to gain insight into the adsorption mechanism. MnFe₂O₄/G could recycle up to 4 cycles, which may be beneficial for further practical water treatment.
显示更多 [+] 显示较少 [-]Cooperation mechanisms for a competitive, sustainable food supply chain to reduce greenhouse gas emissions 全文
2022
Manteghi, Yashar | Arkat, Jamal | Mahmoodi, Anwar
The food industry is a major source of greenhouse gases (GHG). Given that consumers in this industry are aware of the negative consequences of GHG emissions, such as global warming and climate change, members of the food supply chain should consider mechanisms to reduce GHG emissions. The purpose of this paper is to examine the effects of supply chain structure and cooperation methods on the objectives and decisions of a sustainable food supply chain composed of one manufacturer and two suppliers. In the first scenario, a single-level problem is solved for a centralized supply chain. Other scenarios consider the decentralized structure, in which supply chain members face constraints such as maximum additive use and GHG emission, budget, and capacity. The bi-level programming is used to model competition between members of the sustainable food supply chain. It is demonstrated first that the lower-level models in decentralized scenarios can be converted to a single-level model, and then the proposed bi-level model is converted to a single-level one using the KKT method. Computational results show that the alliance of the manufacturer and the first supplier yields the highest total profit for all decentralized scenarios. Because the lowest GHG emission rate among decentralized scenarios is achieved through alliance and cost-sharing mechanisms, the use of these mechanisms concurrently is appropriate for environmental purposes. In scenarios where supply chain members compete with each other, it is found to be cost-effective to increase the budget. Additional considerations can be made regarding the effects of other variables such as distance and advertising on demand as well as alternative forms of the demand function.
显示更多 [+] 显示较少 [-]Carbon variation of dry grasslands in Central Asia in response to climate controls and grazing appropriation 全文
2022
Zhu, Shihua | Chen, Xi | Zhang, Chi | Fang, Xia | Cao, Liangzhong
Quantification of grassland carbon (C) variations is necessary for understanding how grazing and climate change interact to regulate carbon capture and release. Central Asia (CA) has the largest temperate grassland belt in the world and unique temperate dryland ecosystems, which experienced severe climate change and grazing-induced disturbances. However, the impact of grazing on C dynamics is highly uncertain owing to climate variations. Here, an arid ecosystem model (AEM) supplemented with a grazing module that specifically addressed physiological and ecological characteristics of dryland vegetation was developed to quantitatively simulate grassland C dynamics in response to changes in precipitation, temperature, grazing intensity, and CO₂ level in the past decades. The regional simulation results showed that net primary productivity (NPP) was affected mainly by precipitation (in 59% of the studied area). Grazing had a negative effect on NPP and C stocks, whereas overcompensation occurred in 25.71% of the studied area, mainly in the dry western parts. The complex interaction effects of climate, CO₂, and grazing negatively affected productivity, with a grassland NPP decrease of − 1.14 g C/m²/a and high interannual variability. We found that the temporal pattern of cumulative C sequestration, especially total C and vegetation C (VEGC), closely followed the annual fluctuations of precipitation. VEGC stocks decreased from 182.22 to 177.82 g C/m², with a very low value between 1998 and 2008, when precipitation significantly decreased. The results indicate that southern Xinjiang and the Turgay Plateau of Kazakhstan are ecologically fragile areas due to grassland degradation.
显示更多 [+] 显示较少 [-]Emergence of microneedles as a potential therapeutics in diabetes mellitus 全文
2022
Zahoor, Ishrat | Singh, Sukhbir | Behl, Tapan | Sharma, Neelam | Naved, Tanveer | Subramaniyan, Vetriselvan | Fuloria, Shivkanya | Fuloria, Neeraj Kumar | Bhatia, Saurabh | Al-Harrasi, Ahmed | Aleya, Lotfi | Wani, Shahid Nazir | Vargas-De-La-Cruz, Celia | Bungau, Simona
Diabetes mellitus is a severe condition in which the pancreas produces inadequate insulin or the insulin generated is ineffective for utilisation by the body; as a result, insulin therapy is required for control blood sugar levels in patients having type 1 diabetes and is widely recommended in advanced type 2 diabetes patients with uncontrolled diabetes despite dual oral therapy, while subcutaneous insulin administration using hypodermic injection or pump-mediated infusion is the traditional route of insulin delivery and causes discomfort, needle phobia, reduced adherence, and risk of infection. Therefore, transdermal insulin delivery has been extensively explored as an appealing alternative to subcutaneous approaches for diabetes management which not only is non-invasive and easy, but also avoids first-pass metabolism and prevents gastrointestinal degradation. Microneedles have been commonly investigated in human subjects for transdermal insulin administration because they are minimally invasive and painless. The different types of microneedles developed for the transdermal delivery of anti-diabetic drugs are discussed in this review, including solid, dissolving, hydrogel, coated, and hollow microneedles. Numerous microneedle products have entered the market in recent years. But, before the microneedles can be effectively launched into the market, a significant amount of investigation is required to address the numerous challenges. In conclusion, the use of microneedles in the transdermal system is an area worth investigating because of its significant benefits over the oral route in the delivery of anti-diabetic medications and biosensing of blood sugar levels to assure improved clinical outcomes in diabetes management.
显示更多 [+] 显示较少 [-]Investigation into the role of Stmn2 in vascular smooth muscle phenotype transformation during vascular injury via RNA sequencing and experimental validation 全文
2022
Ke, Xiao | Guo, Wenyu | Peng, Yanren | Feng, Zongming | Huang, Yi-teng | Deng, Ming | Wei, Min-xin | Wang, Zan-xin
This study examined the effects of Stmn2 on phenotype transformation of vascular smooth muscle in vascular injury via RNA sequencing and experimental validation. Total RNA was extracted for RNA sequencing after 1, 3 and 5 days of injury to screen the differentially expressed genes (DEGs). Western blot was used to detect the protein expression of Stmn2 and its associated targets. The morphological changes of carotid arteries in rats were examined by hematoxylin and eosin (H&E) staining. The expression of vascular smooth muscle cell (VSMC) phenotype markers smooth muscle alpha-actin (α-SMA), vimentin and OPN were detected by immunohistochemistry. DEGs were related to the extracellular matrix and other cell components outside the plasma membrane. They were associated with protein binding, cytoskeleton protein binding, signal receptor binding and other molecular functions, actin cytoskeleton regulation and other Kyoto Encyclopedia of Genes and Genomes pathways. Stmn2 was identified as the hub gene of actin cytoskeleton pathway and vascular disease, and its expression followed the trend of decreasing initially and increasing afterwards during the progress of vascular injury. Western blot assay showed that the expression of Stmn2 and Tubulin decreased immediately after vascular injury; Stmn2 overexpression significantly up-regulated the expression of osteopontin and α-SMA and vimentin in VSMCs. The results of morphology analysis and immunostaining also showed that Stmn2 overexpression promoted the intima thickening and enhanced the proliferating cell nuclear antigen expression in the injured vascular tissues. In conclusion, our results implied that Stmn2 may play a potential role in vascular injury, which may be associated with VSMC phenotype transformation. Further studies are warranted to determine detailed molecular mechanisms of Stmn2 in vascular injury.
显示更多 [+] 显示较少 [-]A review of spatiotemporal patterns of neonicotinoid insecticides in water, sediment, and soil across China 全文
2022
Liu, Zhikun | Zhang, Leiming | Zhang, Zulin | An, Lihui | Hough, Rupert | Hu, Peng | Li, Yi-Fan | Zhang, Fuxiang | Wang, Shuang | Zhao, Yunqing | Ke, Yuxin | Cui, Song
Neonicotinoid insecticides (NNIs) have been widely used to control insect pests, while their environmental residues and associated hazardous impacts on human and ecosystem health have attracted increasing attention worldwide. In this study, we examined the current levels and associated spatial and temporal patterns of NNIs in multiple environmental media across China. Concentrations of NNIs in surface water, sediment, and soil were in the range of 9.94–755 ng·L⁻¹, 0.07–8.30 ng·g⁻¹ DW, and 0.009–356 ng·g⁻¹ DW, respectively. The high levels of NNIs in surface water, such as in Yangtze River (755 ng·L⁻¹), North River (539 ng·L⁻¹), Nandu River (519 ng·L⁻¹), and Minjiang River (514 ng·L⁻¹), were dominated by imidacloprid, thiamethoxam, and acetamiprid due to their extensive use. The levels of NNIs in sediments were relatively low, and the highest concentration (8.30 ng·g⁻¹ DW) was observed in Dongguan ditch. Sediment–water exchange calculated from fugacity fraction indicated that NNIs in sediment can be released back into the water due to their high solubility and low KOW. Soils from agricultural zones contained the largest residual NNIs, with imidacloprid concentrations in cultivated soil reaching 119 ng·g⁻¹ DW. The calculated leaching potential showed that clothianidin has the highest migration potential to deep soil or groundwater. The monitored data of NNIs presented a decreasing trend from 2016 to 2018, which might be caused by the implementation of relevant control policies for NNI applications. The high levels of NNIs mainly occurred in southern China due to frequent agricultural activities and warm and humid meteorological conditions. The results from this study improve our understanding of the pollution levels and environmental behavior of NNIs in different environmental media across China and provide new knowledge that is needed for making future control policies for NNIs production and application.
显示更多 [+] 显示较少 [-]Evaluation of occurrence of organic, inorganic, and microbial contaminants in bottled drinking water and comparison with international guidelines: a worldwide review 全文
2022
Pourfadakari, Sudabeh | Dobaradaran, Sina | De-la-Torre, Gabriel E. | Mohammadi, Azam | Saeedi, Reza | Spitz, Jorg
The aim of this study was to evaluate the levels of inorganic and organic substances as well as microbial contaminants in bottled drinking water on a global scale. The findings were compared to WHO guidelines, EPA standards, European Union (EU) directive, and standards drafted by International Bottled Water Association (IBWA). Our review showed that 46% of studies focused on the organic contaminants, 25% on physicochemical parameters, 12% on trace elements, 7% on the microbial quality, and 10% on microplastics (MPs) and radionuclides elements. Overall, from the 54 studies focusing on organic contaminants (OCs) compounds, 11% of studies had higher OCs concentrations than the standard permissible limit. According to the obtained results from this review, several OCs, inorganic contaminants (IOCs), including CHCl₃, CHBrCl₂, DEHP, benzene, styrene, Ba, As, Hg, pb, Ag, F, NO₃, and SO₄ in bottled drinking water of some countries were higher than the international guidelines values that may cause risks for human health in a long period of time. Furthermore, some problematic contaminants with known or unknown health effects such as EDCs, DBP, AA, MPs, and some radionuclides (⁴⁰K and ²²²Rn) lack maximum permissible values in bottled drinking water as stipulated by international guidelines. The risk index (HI) for OCs and IOCs (CHBrCl₂, Ba, As, and Hg) was higher than 1 in adults and children, and the value of HI for CHCl₃ in children was more than 1. Thus, further studies are required to have a better understanding of all contaminants levels in bottled drinking water.
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