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Результаты 4941-4950 из 6,560
The effects of pretreatment with lithium metaborate dihydrate on lipid peroxidation and Ca, Fe, Mg, and K levels in serum of Wistar albino male rats exposed to Cd Полный текст
2020
Taşdemir, Muhammed | Çelikezen, Fatih Çağlar | Oto, Gökhan | Özbey, Fahrettin
Boron and boron compounds have beneficial biological effects. Lithium metaborate dihydrate (LMBDH) is used in many branches of industry. Despite its wide industrial use, there is limited information about its biological effects on antioxidant defense system and trace element homeostasis. Therefore, the aim of this study was to evaluate the in vivo protective effects of LMBDH against CdCl₂-induced oxidative stress and imbalance of some bioelements for the first time. In the study, totally 20 Wistar albino male rats were used. The rats were fed with pellet food and water ad libitum and divided into four groups including five rats in each. Group I was control group (standard pellet food + water + normal saline), Group II was CdCl₂ (4.58 mg/kg/body weight/intraperitoneally/single dose), Group III was LMBDH (15 mg/kg/body weight/day orally, for 5 days), Group IV was CdCl₂ (4.58 mg/kg/body weight/intraperitoneally/single dose in fifth day), and LMBDH (15 mg/kg/body weight/day orally for 5 days). The results showed that CdCl₂ treatment increased blood MDA level and decreased antioxidant enzyme activities and the level of blood GSH compared to control group. Pretreatment with LMBDH significantly decreased MDA levels and increased SOD activity (p < 0.05). In addition, Ca, Fe, and K levels decreased in LMBDH pretreatment group in different statistically levels. However, Mg levels showed an increase in LMBDH pretreatment group. As a result, LMBDH pretreatment decreased MDA status and supported antioxidant system by increasing SOD activity. In addition, it did not exhibit an ameliorative effect on measured bioelement homeostasis.
Показать больше [+] Меньше [-]Catalytic performance promoted on Pt-based diesel oxidation catalyst assisted by polyvinyl alcohol Полный текст
2020
Liang, Yanli | Ding, Xinmei | Wang, Jianli | Zhao, Ming | Dan, Yi | Jiang, Long | Chen, Yaoqiang
Eliminating vehicle emission is of importance due to the severe limit value. The work reports a convenient strategy of improving dispersion of platinum-based catalyst with the assistance of polyvinyl alcohol in a varied addition amount. Following the “two-step” annealing techniques, the catalytic performance of the polymer-assisted catalysts in diesel was obviously enhanced because of the improved dispersion of the platinum. Based on experimental results, the long chains of polymer resulting in the steric effect are presumed to isolate platinum ion, inhibiting the aggregation of platinum particles and then improving its dispersion. And the hydroxyl bonding between the polymers could convey electron to platinum species, leading to the lower platinum valence state. Both effects are positive resulting in an excellent NO maximum conversion of around 65% at the optimal introduction of 5 mass% of polymer, as the diesel oxidation catalyst (DOC), which could be inclined to a good purification in the diesel aftertreatment. Hopefully, the convenient research method could initiate the exploration and application of polymer-assisted catalysts for well-dispersed noble metal nanoparticles in eliminating exhaust emission.
Показать больше [+] Меньше [-]Implementation of data intelligence models coupled with ensemble machine learning for prediction of water quality index Полный текст
2020
Abba, Sani Isah | Phạm, Quó̂c Bảo | Saini, Gaurav | Linh, Nguyen Thi Thuy | Ahmed, Ali Najah | Mohajane, Meriame | Khaledian, Mohammadreza | Abdulkadir, Rabiu Aliyu | Bach, Quang-Vu
In recent decades, various conventional techniques have been formulated around the world to evaluate the overall water quality (WQ) at particular locations. In the present study, back propagation neural network (BPNN) and adaptive neuro-fuzzy inference system (ANFIS), support vector regression (SVR), and one multilinear regression (MLR) are considered for the prediction of water quality index (WQI) at three stations, namely Nizamuddin, Palla, and Udi (Chambal), across the Yamuna River, India. The nonlinear ensemble technique was proposed using the neural network ensemble (NNE) approach to improve the performance accuracy of the single models. The observed WQ parameters were provided by the Central Pollution Control Board (CPCB) including dissolved oxygen (DO), pH, biological oxygen demand (BOD), ammonia (NH₃), temperature (T), and WQI. The performance of the models was evaluated by various statistical indices. The obtained results indicated the feasibility of the developed data intelligence models for predicting the WQI at the three stations with the superior modelling results of the NNE. The results also showed that the minimum values for root mean square (RMS) varied between 0.1213 and 0.4107, 0.003 and 0.0367, and 0.002 and 0.0272 for Nizamuddin, Palla, and Udi (Chambal), respectively. ANFIS-M3, BPNN-M4, and BPNN-M3 improved the performance with regard to an absolute error by 41%, 4%, and 3%, over other models for Nizamuddin, Palla, and Udi (Chambal) stations, respectively. The predictive comparison demonstrated that NNE proved to be effective and can therefore serve as a reliable prediction approach. The inferences of this paper would be of interest to policymakers in terms of WQ for establishing sustainable management strategies of water resources.
Показать больше [+] Меньше [-]Prenatal and childhood exposure to chlordecone and sex-typed toy preference of 7-year-old Guadeloupean children Полный текст
2020
Cordier, Sylvaine | Forget-Dubois, Nadine | Desrochers-Couture, Mireille | Rouget, Florence | Michineau, Leah | Monfort, Christine | Thome, Jean Pierre | Kadhel, Philippe | Multigner, Luc | Muckle, Gina
Chlordecone was used intensively as an insecticide in the French West Indies. Because of its high persistence, the resulting contamination of food and water has led to chronic exposure of the general population as evidenced by its presence in the blood of people of Guadeloupe, in particular in pregnant women and newborns, and in maternal breast milk. Chlordecone is recognized as a reproductive and developmental toxicant, is neurotoxic and carcinogenic in rodents, and is considered as an endocrine-disrupting compound with well-established estrogenic and progestogenic properties both in vitro and in vivo. The question arises of its potential consequences on child neurodevelopment following prenatal and childhood exposure, in particular on behavioral sexual dimorphism in childhood. We followed 116 children from the TIMOUN mother–child cohort study in Guadeloupe, who were examined at age 7. These children were invited to participate in a 7-min structured play session in which they could choose between different toys considered as feminine, masculine, or neutral. The play session was video recorded, and the percentage of the time spent playing with feminine or masculine toys was calculated. We estimated associations between playtime and prenatal exposure to chlordecone (assessed by concentration in cord blood) or childhood exposure (determined from concentrations in child blood obtained at the 7-year follow-up), taking into account confounders and co-exposures to other environmental chemicals. We used a two-group regression model to take into account sex differences in play behavior. Our results do not indicate any modification in sex-typed toy preference among 7-year-old children in relation with either prenatal or childhood exposure to chlordecone.
Показать больше [+] Меньше [-]Rapid immobilization of viable Bacillus pseudomycoides in polyvinyl alcohol/glutaraldehyde hydrogel for biological treatment of municipal wastewater Полный текст
2020
Mehrotra, Tithi | Zaman, Mohammad Nawaid | Prasad, Bhim Bali | Shukla, Anuradha | Aggarwal, Srijan | Singh, Rachana
A new approach for easy synthesis of Bacillus pseudomycoides immobilized polyvinyl alcohol (PVA)/glutaraldehyde (GA) hydrogel for application in a wastewater treatment system is reported. Optimization studies revealed that GA/PVA mass ratio of 0.03 and acidic pH of 2 were required for hydrogel synthesis and eventually for bacterial cell immobilization. The synthesized crosslinked matrix possessed a pore size suitable for microbial cell entrapment while maintaining cell accessibility to external environment for bioremediation. Possible crosslinking and bacterial cell immobilization in the hydrogel were evidenced by FTIR, XRD, and SEM studies, respectively. Further, the extent of crosslinking of GA with PVA was investigated and confirmed by transmittance and permeability experiments. The viability and proliferation of hydrogel embedded cells (after 25 days) was confirmed by confocal fluorescence microscopy which also indicated that acidic pH of polymer solution did not affect the immobilized live cells. B. pseudomycoides immobilized hydrogel were demonstrated to be effective for treatment of municipal wastewater and reduced biochemical oxygen demand (BOD), chemical oxygen demand (COD), and protein content below the recommended levels. Overall, the results from this bench-scale work show that employing bacteria-embedded PVA/GA hydrogel for the treatment of municipal wastewater yield promising results which should be further explored in pilot/field-scale studies.
Показать больше [+] Меньше [-]Disaster resilience assessment based on the spatial and temporal aggregation effects of earthquake-induced hazards Полный текст
2020
Liu, Bin | Han, Suyue | Gong, Hao | Zhou, Zhongli | Zhang, Di
Since the “5.12” Wenchuan earthquake in 2008, frequent geologic hazards along the Longmenshan fault zone have had significant impacts on the socioeconomic conditions in the earthquake-stricken areas. Therefore, from the perspective of earthquake-induced hazards, this paper focuses on analyzing the change rules of disaster resilience under the spatial and temporal aggregation effects of earthquake-induced hazards, and this analysis provides an important basis for understanding the developmental characteristics of earthquake-induced hazards and disaster prevention, and mitigation after earthquakes. This paper takes Wenchuan County as an example. By collecting the 2008–2018 landslide geological hazards data, the global autocorrelation coefficient and local autocorrelation coefficient are adopted to analyze the temporal trends and spatial patterns of earthquake-induced hazards. At the same time, from the socioeconomic perspective, two disaster resilience indexes, the compatibility coefficient of industrial and employment structure and per capita GDP growth rate, were constructed to analyze the disaster resilience under the spatial and temporal aggregation effect of landslide geological hazards. The results show that, on the temporal trend, the temporal aggregation effect of earthquake-induced hazards has periodically decayed with time; in the spatial distribution, the spatial clustering effect as a whole increases first and then decreases, and the scope of the aggregation effect tends to narrow spatially. Disaster resilience (Hₓy and RGDP) showed a trend of increasing first and then decreasing, and could not recover to the level before the earthquake in 2017, indicating that Wenchuan County was greatly affected by earthquake-induced hazards in the post-earthquake reconstruction process.
Показать больше [+] Меньше [-]The impact of official development assistance on the economic growth and carbon dioxide mitigation for the recipient countries Полный текст
2020
Lee, Sue Kyoung | Choi, Gayoung | Lee, Eunmi | Jin, Taeyoung
The purpose of this study is to investigate the relationship between official development assistance (ODA) on CO₂ emissions based on both direct and indirect frameworks, using the annual panel data of 30 recipient countries of Korea from 1993 to 2017. It employs a modified impact, population, affluence, and technology (IPAT) model and a simultaneous equation framework for the direct model and indirect model, respectively. The empirical results suggest that ODA has both a direct and an indirect mitigation impact in the recipient countries. Compared to the direct impact, a small indirect mitigation impact of ODA on CO₂ emissions is derived. However, the estimation results of the environmental Kuznets curve (EKC) equation imply that economic growth has the potential of mitigating the environmental degradation when the economic development in recipient countries of Korea reaches a certain level. Therefore, the bilateral cooperation, through ODA and the supportive policy, should make an effort to promote economic development and mitigation of environmental degradation in developing countries.
Показать больше [+] Меньше [-]Effects of glyphosate on microcystin-LR production and release from Microcystis aeruginosa at different temperatures Полный текст
2020
Ye, Jing | Guan, Ying | Wu, Liang | Wang, Chunhui | Chen, Jiawen | Zhou, Shanshan | Xu, Chao
Cyanobacterial blooms and their associated toxins are growing issues for many aquatic ecosystems. Microcystin-LR (MC-LR) is a toxic and common cyanobacterial toxin, whereas glyphosate is a commonly used herbicide that is massively applied in agriculture. In this study, the effects of glyphosate on the growth of Microcystis aeruginosa and MC-LR synthesis and release from M. aeruginosa at different temperatures are investigated. In addition, the MC-LR pollution in the Huangpu River in Shanghai urban area is studied. Results indicated that the MC-LR concentration in the Huangpu River is related to water temperature. The laboratory experiments revealed that the growth of M. aeruginosa was slightly promoted at 15 °C and glyphosate concentrations of 1 and 5 mg/L and inhibited in the presence of glyphosate and high temperatures (20 °C, 25 °C, 30 °C, and 35 °C). The intracellular MC-LR contents were remarkably increased by glyphosate at 15 °C, 20 °C, 25 °C, and 30 °C and remarkably decreased at 35 °C. Meanwhile, the extracellular MC-LR contents were remarkably increased at all temperatures and all concentrations except when treated with 1 mg/L glyphosate at 35 °C. The highest extracellular MC-LR content, which was 143.9% higher compared with that of the control, was observed at 30 °C and treatment with 10 mg/L glyphosate. These results were consistent with those of MC-LR investigation in Huangpu River. Furthermore, in accordance with the intracellular MC-LR contents, the ability of a single cell to synthesize MC-LR was enhanced at 15 °C, 20 °C, 25 °C, and 30 °C and decreased at 35 °C. These results provide an understanding on the toxic effects of glyphosate on cyanobacteria and the effects of temperature on MC release. Moreover, these results will be helpful in protecting aquatic ecosystems and human health.
Показать больше [+] Меньше [-]Different inhibitory mechanisms of chlortetracycline and enrofloxacin on mesophilic anaerobic degradation of propionate Полный текст
2020
Gou, Min | Wang, Huizhong | Li, Jie | Sun, ZhaoYong | Nie, Yong | Nobu, Masaru Konishi | Tang, Yueqin
In anaerobic digestion, propionate is a key intermediate whose degradation is thermodynamically challenging and accumulation is detrimental to the process. Many wastewater streams contain antibiotics due to its globally increasing use, and these compounds can inhibit methane production. However, the effect of antibiotics on propionate degradation in anaerobic digestion remains unclear. In this study, the influence of two antibiotics (chlortetracycline [CTC] and enrofloxacin [EFX]) on biogas production and mesophilic propionate-degrading microbial community was investigated. CTC strongly repressed propionate oxidation, acetate utilization, and methane production, while EFX only inhibited propionate oxidation and methane production to a lesser extent. Microbial community analyses showed that syntrophic propionate-oxidizing bacteria (SPOB) Syntrophobacter had strong tolerance to both CTC and EFX. CTC inhibition mainly acted on the activity of acetate-oxidizing bacteria (Mesotoga, Geovibrio, Tepidanaerobacter, unclassified Bacteroidetes, and unclassified Clostridia) and acetoclastic methanogen, while EFX inhibition applied to the SPOB Smithella and acetoclastic methanogen. Network analysis further indicated that more complicated correlation among bacterial genera occurred in CTC treatments. These results suggested that CTC and EFX inhibited propionate degradation via different mechanisms, which was the result of joint action by antibiotics and microbial interactions.
Показать больше [+] Меньше [-]Effect of diurnal temperature range on outpatient visits for common cold in Shanghai, China Полный текст
2020
Ma, Yuxia | Yang, Sixu | Yu, Zhiang | Jiao, Haoran | Zhang, Yifan | Ma, Bingji | Zhou, Ji
To evaluate the correlations between diurnal temperature range (DTR) and the number of outpatient visits for common cold from Jan. 1, 2008, to Dec. 31, 2010, in the Shanghai metro area; we used a distributed lag non-linear model together with a Poisson regression model. The controlling factors included long-term trends and day of the week in outpatient visits for common cold and the selected weather elements. The entire study group was divided into three different age subgroups, including ≤ 15, 15–65, and ≥ 65 years old. We found some non-linear J-patterns between DTR and daily outpatient visits for common cold. At lag 0 day, the number of outpatient visits for common cold would increase by 11.1% per 1 °C increase in DTR. The greater the DTR, the more it affects outpatient visits for common cold, especially for the ≥ 65 years age group. In addition, DTR plays a more important role in outpatient visits for common cold in spring and winter compared with other seasons of the year. Our study showed that DTR is a risk factor that contributes to common cold. Results in this study can provide scientific evidence for the local authorities in improving preventive measures of the healthcare system.
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