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Результаты 4171-4180 из 8,010
Assessing urbanization efficiency and its influencing factors in China based on Super-SBM and geographical detector models Полный текст
2021
Qian, Xiangyan | Wang, Di | Nie, Rui
Improving urbanization efficiency (UE) has gradually become an important requirement for the development of new-type urbanization. In this paper, first, we applied the Super-SBM model with undesirable outputs and Malmquist index to evaluate the UE of 30 provinces in China from 2006 to 2016 based on static and dynamic perspectives. Second, influencing factors were explored using the novel geographical detector model. The results show that China’s UE was not high overall and was increasing slowly. Regionally, the UE presented a high-to-low spatial evolution from east to west. Technical change was the main reason for the slow growth in efficiency, and undesirable outputs (pollutant emissions) were the key to efficiency loss. Over the study period, GDP per capita and urbanization rate had the greatest determining power on the UE, but their determination power was declining. Meanwhile, the impact of research and development (R&D) and foreign direct investment (FDI) on UE became increasingly important. Finally, some suggestions for improving the urban ecological environment and UE in China are discussed.
Показать больше [+] Меньше [-]Phthalates leaching from plastic food and pharmaceutical contact materials by FTIR and GC-MS Полный текст
2021
Andjelković, Tatjana | Bogdanović, Danica | Kostić, Ivana | Kocić, Gordana | Nikolić, Goran | Pavlović, Radmila
Phthalates are often used as plasticizers in the production of plastic food contact materials (FCMs) and pharmaceutical contact materials (PCMs), and having in mind that they are not bound to plastics, phthalates may easily leach from plastics under certain conditions. The aim of this research is determination of phthalates leaching potential from different plastic materials and quantitative determination of 5 phthalates (dimethyl phthalate (DMP), di-n-butyl phthalate (DnBP), benzyl butyl phthalate (BBP), diethyl hexyl phthalate (DEHP), and di-n-octyl phthalate (DOP)) in 44 different plastic articles of 7 different plastic polymers used as FCMs and PCMs by FTIR, GC-MS, and gravimetric methods. The FTIR technique is shown to be rapid method for determination of phthalate content in PVC articles. Comparing of FTIR method with GC-MS and gravimetric showed that separation and quantitative determination of each phthalate separately favor the GC-MS method, because FTIR method determines the total amount of phthalate content. However, the FTIR method is less expensive and demanding in terms of sample preparation, which is suited for use in pre-screening analysis. The results of GC-MS phthalates determination showed that PVC articles used as PCMs contain DEHP in significant amount, from 5.19 to 28.76% by weight and could be a potential risk to human health.
Показать больше [+] Меньше [-]Incorporation of natural assumption to deal with cancer Полный текст
2021
Karthika, Chenmala | Sureshkumar, Raman
The current state of the art for the use of natural ingredients for cancer therapy is by reviewing the publications and findings associated with cancer research with the employment of flavonoids. Cancer is the most furious disease making fear in the eyes of mankind. Though various treatment methods are prevalent, the patient’s choices are shifting from synthetic treatment strategy to the natural ones. The plant-based metabolites are used very often in our life as a food additive and also as a medicine for primary health care. The safety profile and its efficacy add on advantage for the incorporation of the natural products separately or in combination as a remedy for cancer. Flavonoids, the plant-based metabolites are proven for their anti-inflammatory, anti-oxidant, and anti-cancer properties. Their chemotherapeutic and chemosensitizing power had made it interesting for the researchers to dig more on the health benefits of the flavonoids and incorporating it in a holistic approach, with its natural benefits to relieve the pain and the symptoms of the patient suffering from various medical conditions. The predominant approach for the management of cancer is by following safe and effective treatment modality. In this review, we mentioned the benefits of the flavonoids for the management of various cancers and its potency as a chemotherapeutic agent and as the chemosensitizer. Our mother nature had given remedies to cure various diseases in both human beings and animals by it; we just need to find out the sources and access to them.
Показать больше [+] Меньше [-]Spatial–Temporal Growth, Distribution, and Diffusion of Marine Microplastic Research and National Plastic Policies Полный текст
2021
Harris, Lyda S. T. | Fennell, Jackson | Fales, Robin J. | Carrington, Emily
Plastics account for 80% of material waste in the ocean. The field of marine microplastic (MP) research is relatively new and growing rapidly, in terms of published papers as well as institutions and countries conducting research. To combat plastic pollution, there is sufficient evidence that policies can lead to reduced plastic production and consumption both locally and globally. We aim to understand how marine MP research and national plastic policies have individually grown and spread. Specifically, we used scientometric and spatial diffusion methods to best explain how ideas (science and policy) clustered and spread geographically through time. We performed systematic literature searches to determine the spatial and temporal growth of marine MP publications and national plastic policies from 1900–2019. We found that more countries adopted national plastic policies than those that have conducted marine MP research. At each level of analysis (publication, institution, and country levels) within each field (research and policy), the temporal growth rate had a break point where doubling time changed significantly. Marine MP research grew exponentially, where doubling times ranged 1.1–3.7 years and the topics of inquiry increased steadily. National plastic policies also grew exponentially, where doubling times ranged 3.3–4.1 years. Different diffusion methods explain spatial growth, where marine MP research spread was best explained by a hybrid of expansion and relocation diffusion while national plastic policy spread was best explained by expansion diffusion. Both marine MP research and national plastic policies continue to spread, increasing global knowledge and mitigation efforts of plastic pollution.
Показать больше [+] Меньше [-]Distribution and assessment of cadmium contamination in sediments from the Four River inlets to Dongting Lake, China Полный текст
2021
Wu, Yangyuan | Peng, Bo | Fang, Xiaohong | Xie, Shurong | Li, Xiaomin | Jiang, Chunxia | Dai, Yanan
The total concentrations of Cd in bulk sediments and those of the BCR sequential extraction fractions of sediments from inlets of the Four Rivers that feed Dongting Lake were determined using ICP-MS techniques. The results suggested that Cd was heterogeneously distributed in the inlet sediments of the rivers, with the highest degree of enrichment in sediments from the Xiangjiang River. The Cd anomaly was defined as Cd enrichment in sediments with an EF (enrichment factor) > 10.0, and it was identified in the inlet sediments of the Xiangjiang River. Cd in the sediments was dominated by acid-soluble Cd at a proportion of 23.9–69.8 (%) compared to its total concentrations in the sediments. The inlet sediments of the Four Rivers were contaminated with Cd, with the highest degree of contamination in the inlet sediments of the Xiangjiang River. The Cd contamination as well as the Cd anomaly in the sediments were closely related to the industrial activities (e.g. smelting and refining for ore minerals) in the areas, and Cd contamination at high levels may represent an ecological risk for the lake watershed. Cd contamination of the inlet sediments may also impact the lake basin sediments and is harmful to the lake ecological system, particularly for sediments of the Xiangjiang River. Therefore, it is essential to control and treat Cd contamination in the inlet sediments for ecological environmental protection of lake watersheds.
Показать больше [+] Меньше [-]Removal of Thiophene and 4,6-Dimethyldibenzothiophene by Adsorption on Different Kinds of Starches Полный текст
2021
Baeza, Patricio | Pasten, Bárbara | Concha, Jacqueline | Ojeda, Juan
The desulfurization by adsorption of thiophene and 4,6-dimethyldibenzothiophene on unripe banana starch, dessert banana starch, corn starch, and porous corn starch was studied. The adsorbents were characterized by scanning electron microscopy, surface acidity measurement, and infrared spectroscopy with attenuated total reflection. The results showed low values of adsorption of both sulfur molecules on both banana starches, which is due to the absence of cavities or pores in their structure. In the case of corn starch, the presence of cavities or pores allows a greater adsorption capacity for thiophene and 4,6-dimethyldibenzothiophene. The mechanism of interaction between sulfured molecules and the starches can occur through free electron pair of sulfur or the π electron cloud of the aromatic ring with the Brönsted acid site of starches. The enzymatic modification applied to corn starch allowed obtaining a material with a greater number of cavities or pores, but that maintains their structure and physicochemical properties. The presence of pores of a larger size allows adsorbing a greater amount of sulfured molecules in comparison to the native starch.
Показать больше [+] Меньше [-]Toxic cyanobacteria and microcystin dynamics in a tropical reservoir: assessing the influence of environmental variables Полный текст
2021
Phạm, Thanh Lưu | Tran, Thi Hoang Yen | Shimizu, Kazuya | Li, Qintong | Utsumi, Motoo
Toxic cyanobacterial blooms (TCBs) have become a growing concern worldwide. The present study investigated the dynamic of toxic cyanobacteria and microcystin (MC) concentrations in the Tri An Reservoir (TAR), a tropical system in Vietnam, with quantitative real-time polymerase chain reaction (qPCR) and high-performance liquid chromatography (HPLC), respectively. The results of the qPCR quantification revealed that Microcystis was the dominant group and the primary MC producer in the TAR. Potentially toxigenic cyanobacteria varied from 1.2 × 10⁴ to 1.58 × 10⁷ cells/mL, and the mean proportion of toxic Microcystis to that of the total toxic cyanobacteria varied from 21 to 88%. Microcystin concentrations in raw water and sediment samples often peaked during June to October as blooms occurred and varied from 0.27 to 6.59 μg/L and from 1.79 to 544.9 ng/g in wet weight, respectively. The results of this study indicated that conditions favoring Microcystis proliferation lead to the selection of more toxic genotypes. Water temperature and light availability were not driving factor in the formation of TCBs in the TAR. However, the high loads of total nitrogen (TN), phosphate, and total phosphorus (TP) into the water via rainfall runoff in combination with a high total suspended solid (TSS) and decreased water level during the early months of the rainy seasons did lead to a shift in Microcystis blooms and higher proportions of toxic genotypes of Microcystis in the TAR. This research may provide more insight into the occurrence mechanism of TCBs in tropical waters. The strategy to control TCB problems in tropical regions should be focused on these limnological and hydrological parameters, in addition to a reduction in nitrogen and phosphorus loading.
Показать больше [+] Меньше [-]Efficiency and comprehensive risk assessment of soil Pb and Cd by washing technique with three biodegradable eluents Полный текст
2021
Zhong, Qinmei | Zhang, Shirong | Pan, Xiaomei | Wang, Guiyin | Xu, Xiaoxun | Li, Ting | Zhou, Wei | He, Yan | Luo, Ling | Liu, Yan | Long, Lulu
Soil washing with environmentally friendly eluents is a rapid remediation technique for farmland polluted by heavy metals. In this study, polyepoxysuccinic acid (PESA), ethylenediamine tetra (methylene phosphonic acid) sodium (EDTMPS), and phosphonyl carboxylic acid copolymer (POCA) were applied to remedy paddy and arid soils polluted by Pb and Cd. At the same time, ethylenediaminetetraacetic acid (EDTA) was used as a control eluent. PESA showed comparable removal of soil Pb and Cd (over 80.0%) with EDTA, and EDTMPS and POCA removed two heavy metals by 35.2–50.3%. For labile fractions, PESA significantly removed Pb by 93.5–96.7% and Cd by 84.9–90.3% in two soils. EDTMPS and POCA removed Pb by 75.5–85.8% in two soils, while they only removed Cd by 11.7–42.2% in paddy soil, and 76.3–81.7% in arid soil. The risks of total heavy metal concentrations were reduced from the high risk to low risk in paddy soil, and to considerable risk in arid soil, while only dropped to considerable or even had no change by EDTMPS and POCA leaching. The risks of the two soils reduced from high to low or considerable level after PESA washing based on labile fraction change, and to considerable or high level after EDTMPS and POCA leaching, respectively. Therefore, PESA is an ecological benefit eluent for remediating the farmland polluted by heavy metals, and the risk assessment based on labile fraction more easily identifies the dynamic change of heavy metal during the washing process.
Показать больше [+] Меньше [-]Italian and Japanese public attention toward balneotherapy in the COVID-19 era Полный текст
2021
Maccarone, Maria Chiara | Kamioka, Hiroharu | Cheleschi, Sara | Tenti, Sara | Masiero, Stefano | Kardeş, Sinan
Italian and Japanese public widely use balneotherapy. The population interest in balneotherapy in coronavirus disease-2019 (COVID-19) era should be investigated. Therefore, we aimed to exploit Google Trends analysis, as a measure of peoples’ interest in balneotherapy, in two countries, Italy and Japan. In this infodemiology study, Google Trends was queried for the lay terms widely used by the Italian population to refer to the balneotherapy setting (terme + termale) and by the Japanese to refer to the bathing place and balneotherapy facilities (温泉 + スパ). The internet searches in 2020 were compared to overlapping time spans in 2016–2019 and were correlated with new confirmed cases/deaths. This study demonstrated that from February 23 to June 20, 2020, and from October 4 to December 26, 2020, the internet searches of the Italian words corresponding to balneotherapy were statistically significantly decreased; however, the internet searches were not significantly different in June 21 to October 3, 2020, compared to overlapping time spans in 2016–2019 in Italy. The study also showed that from March 15 to September 5, 2020, and from November 29 to December 26, 2020, the internet searches of the Japanese words corresponding to balneotherapy were statistically significantly decreased; however, the internet searches were significantly increased in September 13 to November 7, 2020, and were not significantly different in November 8 to 28, 2020, compared to overlapping time spans in 2016–2019 in Japan. There were significant negative correlations between the relative search volume and number of new cases (rho=−0.634; p<0.001)/deaths (rho=−0.856; p<0.001) in Italy and the number of new deaths (rho=−0.348; p=0.012) in Japan. Population interest in balneotherapy has changed in the COVID-19 era both in Italy and Japan. During the early stage of pandemic (March to June), the interest was lower. After this early stage, the interest showed a recovery in both countries. In Italy, the population interest reached to its prior levels in late June through early October, with a peak in August. In Japan, the recovery exceeded the prior 4-year levels in mid-September through early November. Then, both countries demonstrated a decline in interest: began in early October in Italy and late November in Japan. This information would allow us to understand/address the population response in the pandemic in respect of the balneotherapy and would guide the preparedness of healthcare providers and planners both in this pandemic and future similar situations.
Показать больше [+] Меньше [-]Sunlight-induced photocatalytic degradation of organic pollutants by biosynthesized hetrometallic oxides nanoparticles Полный текст
2021
Rani, Manviri | Keshu, | Uma Shanker,
Dyes and phenols are extensively used chemicals in petrochemicals, pharmaceuticals, textile, and paints industries. Due to high persistence, bioaccumulation, and toxicity, their removal from the environment is highly imperative by advanced techniques. Single metal oxide nanomaterials are generally associated with limitations of large bandgap (> 3eV) and charge recombination. Therefore, heterometallic oxides (HMOs) as CuFe₂O₄, CuMn₂O₄, and MnZn₂O₄ have been synthesized via green route by employing leaf extract of Azadirachta indica. XRD revealed the crystalline nature of HMOs nanospheres with particle size less than 100 nm. Subsequently, HMOs nanocatalysts were used as photocatalyst for removal of 3-amino phenols (3-AP) and eriochrome black T (EBT) from water under sunlight. Reaction parameters namely pollutant concentration (50–130 mgL⁻¹), catalyst dose (20–100 mg), and pH (3–11) were optimized in order to get best results. Substantial degradation (80–95%) of pollutants (50 mgL⁻¹) by HMOs (80 mg) was achieved at neutral pH under sunlight exposure. Highest removal by CuFe₂O₄ might be due to its high surface area (35.7 m²g⁻¹), low band gap (2.4 eV), larger particle stability (Zeta potential: -22.0 mV), and lower photoluminescence intensity. Sharp declines in curves were visually confirmed by color change and indicated for first-order kinetics of degradation with initial Langmuir adsorption. Spectrophotometric analysis revealed that half-life (t₁/₂) of 3-AP (0.9-1.7 h) and EBT (0.6-0.8 h) were significantly reduced. Faster degradation of EBT than 3-AP was because of less electronegative N-atom at the diazo group. Scavenger analysis indicated the presence of active radicals in photo-catalytic degradation of 3-AP and EBT. All HMOs have shown high reusability (n=8) which ensures their stability, sustainability, and efficiency. Overall, green synthesized HMOs nanoparticles with prominent surface characteristics offer a viable alternative photocatalyst for industrial applications.
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