خيارات البحث
النتائج 3861 - 3870 من 7,291
Airborne concentrations of SARS-CoV-2 in indoor community environments in Italy النص الكامل
2022
Conte, Marianna | Feltracco, Matteo | Chirizzi, Daniela | Trabucco, Sara | Dinoi, Adelaide | Gregoris, Elena | Barbaro, Elena | La Bella, Gianfranco | Ciccarese, Giuseppina | Belosi, Franco | La Salandra, Giovanna | Gambaro, Andrea | Contini, Daniele
COVID-19 pandemic raised a debate regarding the role of airborne transmission. Information regarding virus-laden aerosol concentrations is still scarce in community indoors and what are the risks for general public and the efficiency of restriction policies. This work investigates, for the first time in Italy, the presence of SARS-CoV-2 RNA in air samples collected in different community indoors (one train station, two food markets, one canteen, one shopping centre, one hair salon, and one pharmacy) in three Italian cities: metropolitan city of Venice (NE of Italy), Bologna (central Italy), and Lecce (SE of Italy). Air samples were collected during the maximum spread of the second wave of pandemic in Italy (November and December 2020). All collected samples tested negative for the presence of SARS-CoV-2, using both real-time RT-PCR and ddPCR, and no significant differences were observed comparing samples taken with and without customers. Modelling average concentrations, using influx of customers’ data and local epidemiological information, indicated low values (i.e. < 0.8 copies m⁻³ when cotton facemasks are used and even lower for surgical facemasks). The results, even if with some limitations, suggest that the restrictive policies enforced could effectively reduce the risk of airborne transmissions in the community indoor investigated, providing that physical distance is respected.
اظهر المزيد [+] اقل [-]Biomonitoring of transboundary pollutants using moss in Japan’s mountains النص الكامل
2022
Oishi, Yoshitaka
Long-range transported atmospheric pollutants (or transboundary pollutants) include trace metals with isotope ratios and compositions that vary from those of domestic pollutants, which threaten mountain ecosystems. These differences can be applied as indices to evaluate the influence of transboundary pollutants on mountain ecosystems. Mosses play important ecological functions in mountains and are sensitive to atmospheric deposition. Therefore, using these indices for moss biomonitoring can provide a more accurate indication of ecosystem health. However, studies on indices that are appropriate for moss biomonitoring are limited. Here, the effectiveness of moss biomonitoring using trace metal indices was examined to evaluate transboundary pollutants in mountainous areas in Japan. Transboundary pollutants in these areas originate from mainland Asia and are characterized by high lead isotope ratios, lead-to-zinc (Pb/Zn) ratios, and arsenic-to-vanadium (As/V) ratios. Given that the abundance of transboundary pollutants decreases with distance from mainland Asia, these three indices are also expected to vary with distance. The Pb isotope ratios were found to decrease with distance from mainland Asia; in contrast, the Pb/Zn and As/V ratios did not display any notable relationship with distance. These results are likely attributed to biological and environmental factors that affect trace metal content in moss. Thus, moss Pb isotope ratios are useful indicators of transboundary pollutants in Japan’s mountains, offering an important tool for comparable moss biomonitoring studies in East Asia.
اظهر المزيد [+] اقل [-]Phytoremediation of leachate contaminated soil: a biotechnical option for the bioreduction of heavy metals induced pollution in tropical landfill النص الكامل
2022
Barasarathi, Jayanthi | Auwal, Hassan | Pariatamby, Agamuthu | Hamid, Fauziah Shahul | Uche, Emenike Chijioke
Metal remediation is important considering the environmental pressure due to soil pollution from landfill leachate. Hence, identifying potential plant-based option for remediation, especially the use of bio-/hyper-accumulators, is inevitable. Contamination of soil with heavy metals has been a decades-long concern. This study is therefore aimed to evaluating the metal-remediation potentials of four ornamental plant species—Cordyline fruticosa, Duranta variegated, Tradescantia spathacea, and Chlorophylum comosum—on leachate-contaminated soil. Details of the study involved leachate analysis, soil characterization, and metal-accumulation test on selected plants. Characterization of both landfill soil and leachate has indicated that Pb, Cu, As, Mn, Cr, Zn, Fe, and Ni were higher than the prescribed limits. The high metal reduction efficiency of C. fruticosa on all the studied metals was about 63%, 85%, 77.88%, 77.55%, and 75% for Pb, As, Mn, Zn, and Cr concentrations. The metal removal by the plants was significantly higher as compared to control soil (P < 0.05). The highest removal rate constant witnessed was for Mn (0.023 day⁻¹) and was achieved using C. fruticosa. The results have revealed that C. fruticosa was the most promising plant for the removal of the studied metals. Therefore, it can be concluded that C. fruticosa has potentials to remediate heavy metal–contaminated soil at significant level. The findings will develop investigation into plant-tissue and compartmentalization effect on metal remediation using C. fruticosa.
اظهر المزيد [+] اقل [-]Wire-Tube DBD Reactor for H2S Treatment: Optimization of Materials and Configurations النص الكامل
2022
Xia, Chongjie | Shen, Xinjun | Gu, Jingxue | Zhou, Wei | Liu, Yinxin
Based on the wire-tube dielectric barrier discharge (DBD) reactor, this study investigated the effects of the materials and configurations of high-voltage pole, insulating medium layer and grounding pole on the discharge power, power factor, and ozone concentration of the reactor, respectively. The DBD reactor had the best discharge power and power factor and the highest ozone concentration when the high-voltage pole was the linear copper wire, the insulating medium material was quartz tube, and the grounding pole was the copper wire winding. Based on this optimized DBD reactor, the effect of energy density on the treatment efficiency and ozone concentration of H₂S exhaust gas was further investigated. At the energy density of 2143.1 J L⁻¹, the H₂S exhaust gas treatment efficiency reached 100% and the residual ozone concentration decreased to 0 g m⁻³.
اظهر المزيد [+] اقل [-]Life cycle approach applied to the production of ceramic materials incorporated with ornamental stone wastes النص الكامل
2022
Barbosa, Márcio Zago | de Oliveira Dias, Josinaldo | Marvila, Markssuel Teixeira | de Azevedo, Afonso R. G.
The use of the ornamental stone wastes, such as the originated from granite or marble, has been the subject of technological studies that evaluated its application in ceramic and cement materials; however, some complementary assessments, such as its life cycle assessment, are still not well explored in the literature. Therefore, the objective of this study was to discuss the main environmental impacts related to the manufacture of ceramic specimens, comparing conventional production versus the production of specimens incorporated with ornamental stone wastes. For this, the life cycle assessment was conducted in accordance with ISO 14.040 and 14.044. For this research, the ornamental stone wastes from the municipality of Cachoeiro do Itapemirim–ES and clay from the municipality of Campos dos Goytacazes–RJ were used. The system was modeled, using the SimaPro 9.0 software and the Ecoinvent database 3.3, for the life cycle assessment of the ceramic specimens and the potentiality regarding the use of ornamental stone wastes in ceramic materials using alternative input energy for burning, contributing to the effectiveness of the solid wastes reuse by the ceramic industry. The evaluation identified that the ornamental stone wastes incorporated into the ceramic specimens had significant potential in reducing environmental impacts and that the alternative input energy in burning stage makes them even more relevant. The study points out as the main result, the reduction of 35.74% of the impacts related to the category of the emission of greenhouse gases, and scarcity of mineral resources, 14.83% reduction, when compared to specimens to conventional brick production and alternative brick production, which emphasizes that the ceramic materials with wastes contribute to the mitigation of impacts.
اظهر المزيد [+] اقل [-]Cooperative carbon emission reduction through the Belt and Road Initiative النص الكامل
2022
Mao, Xiangyu | Wang, Ying
Carbon emission reduction under the Belt and Road Initiative has great significance on China’s goal of carbon peak. To better promote carbon emission reduction, based on the background of the Belt and Road Initiative, this paper analyzes the collaborative carbon emission reduction through investment between Chinese enterprises and local enterprises in developing countries along the Belt and Road Initiative. Considering the efforts of enterprises in carbon reduction, low-carbon infrastructure investment, and promotion of low-carbon products, this paper constructs a differential game model of collaborative carbon reduction cooperation between Chinese enterprises and local enterprises in developing countries along the Belt and Road Initiative. By horizontally comparing Nash non-cooperative mode, Stackelberg master-slave mode, and cooperative mode, the results shows that Chinese enterprises can encourage local enterprises in developing countries along the Belt and Road Initiative to coordinate carbon emission reduction through subsidies, which is Stackelberg master-slave mode. Under the cooperative mode, with the maximum carbon emission reduction efforts of both parties, the total benefit of carbon emission reduction reaches the optimal Pareto equilibrium. In addition, this paper also discusses the influence of related factors on the benefits of carbon emission reduction.
اظهر المزيد [+] اقل [-]A review on the removal of phthalate acid esters in wastewater treatment plants: from the conventional wastewater treatment to combined processes النص الكامل
2022
Bai, Lin | Dong, Xiaowan | Wang, Fangshu | Ding, Xiaohan | Diao, Zhikai | Chen, Dong
In the past decades, phthalate acid esters (PAEs), as a new class of recalcitrant environmental contaminant, have attracted increasing concern due to their potential hazards to reproductive system. wastewater treatment plants (WWTPs) are generally regarded as a crucial barrier to prevent a variety of contaminants from introducing into aquatic environment. This paper reviews the occurrence, fate, and removal efficacy of six widely appearing PAEs in conventional wastewater treatment. PAEs removal appears to be compound- and process-dependent. Advanced treatment processes, including activated carbon, advanced oxidation process (AOPs), membrane filtration, and membrane bioreactor, show good performance in PAEs elimination, but many methods have been commercially limited by toxic byproducts, high operation, and maintenance costs. Even though combined processes are qualified as a promising alternative, further studies are required to optimize these processes, especially the competitiveness between technique and economy.
اظهر المزيد [+] اقل [-]Can green trade save the environment? Introducing the Green (Trade) Openness Index النص الكامل
2022
Can, Muhlis | Ben Jebli, Mehdi | Brusselaers, Jan
Environmental degradation is one of the main drivers of climate change. One of the most broadly accepted tools to minimize environmental degradation is the introduction of “green products”. This paper introduces the “Green Trade Openness Index” to (a) measure the importance of green products in a region and (b) revisit the trade-environment nexus in a sample study of 31 OECD countries over the period 2007–2017. The empirical analysis confirms the environmental Kuznets curve hypothesis and — more importantly — demonstrates for the first time that the presence of green products in a country’s trade basket reduces that country’s ecological footprint. This is essential information for practitioners and policy makers looking for a pathway to sustainable development. Finally, the novel index creates opportunities for future research, as the index can be used as explanatory variable in different research questions and fields of research.
اظهر المزيد [+] اقل [-]Efficacy of ginsenoside Rg3 nanoparticles against Ehrlich solid tumor growth in mice النص الكامل
2022
El-Banna, Mona A. | Hendawy, Omnia M. | El-Nekeety, Aziza A. | Abdel-Wahhab, Mosaad A.
Solid tumors are fairly common and face many clinical difficulties since they are hardly surgically resectable and broadly do not respond to radiation and chemotherapy. The current study aimed to fabricate ginsenoside Rg3 nanoparticles (Rg3-NPs) and evaluate their antitumor effect against Ehrlich solid tumors (EST) in mice. Rg3-NPs were fabricated using whey protein isolates (WPI), maltodextrin (MD), and gum Arabic (GA). EST was developed by the injection of mice with Ehrlich ascites cells (2.5 × 10⁶). The mice were divided into a control group, EST group, and the EST groups that were treated orally 2 weeks for with normal Rg3 (3 mg/kg b.w.), Rg3-NPs at a low dose (3 mg/kg b.w.), and Rg3-NPs at a high dose (6 mg/kg b.w.). Serum and solid tumors were collected for different assays. The results revealed that synthesized Rg3-NPs showed a spherical shape with an average particle size of 20 nm and zeta potential of -5.58 mV. The in vivo study revealed that EST mice showed a significant increase in AFP, Casp3, TNF-α, MMP-9, VEGF, MDA, and DNA damage accompanied by a significant decrease in SOD and GPx. Treatment with Rg3 or Rg3-NPs decreased the tumor weight and size and induced a significant improvement in all the biochemical parameters. Rg3-NPs were more effective than Rg3, and the improvement was dose-dependent. It could be concluded that fabrication of Rg3-NPs enhanced the protective effect against EST development which may be due to the synergistic effect of Rg3 and MD, GA, and WPI.
اظهر المزيد [+] اقل [-]Influencing mechanism of non-CO2 greenhouse gas emissions and mitigation strategies of livestock sector in developed regions of eastern China: a case study of Jiangsu province النص الكامل
2022
Xiong, Chuanhe | Su, Weizhong | Li, Hengpeng | Guo, Zheng
The livestock sector not only provides people with meat, eggs, milk, and other nutrients but also causes a large number of non-CO₂ greenhouse gas emissions. It is urgent to explore the influence mechanism of non-CO₂ greenhouse gas emission from the livestock sector and formulate effective mitigation strategies. Taking Jiangsu province as an example, we analyzed the influencing factors of non-CO₂ greenhouse gas emissions from the livestock sector based on sources and modified the STIRPAT (stochastic impact by regression on population, affluence, and technology) model, proposed the directions, designed the generally circular path, and determined the focus of non-CO₂ greenhouse gas emissions reduction from the livestock sector. The results demonstrated: (1) the top priority of emission reduction of livestock sector in Jiangsu province was the reasonable treatment of manure produced by livestock (non-CO₂ greenhouse gas emissions from manure had accounted for more than 60% of the total emissions from the livestock sector since 2007.), and the core was pig manure management (the CH₄ and N₂O emissions from pig manure accounted for more than 90 and 50% of the total CH₄ and N₂O emissions from all livestock manure, respectively). (2) The decrease of the agricultural population, the increase of livestock output value per capita of the agricultural population, and the improvement of livestock carbon productivity all reduced non-CO₂ greenhouse gas emissions of the livestock sector. For every 1% decrease in agricultural population, for every 1% increase in livestock carbon productivity and livestock output value per capita of the agricultural population, non-CO₂ greenhouse gas emissions from the livestock sector would be reduced by 0.0859%, 0.1748%, and 0.0400%, respectively. (3) To construct and improve the low carbon industrial chain of the livestock sector, to promote low carbon technology research and development and introduction are two focuses for non-CO₂ greenhouse gas emission reduction in the livestock sector. The research can provide a basis for non-CO₂ greenhouse gas emissions reduction from the livestock sector in China, especially in the developed eastern regions.
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