خيارات البحث
النتائج 4291 - 4300 من 7,292
Phytoremediation of formaldehyde by the stems of Epipremnum aureum and Rohdea japonica النص الكامل
2022
Decorative plants can efficiently purify formaldehyde and improve the quality of indoor air. The existing studies primarily revealed that the aerial and underground parts of plants’ capacity to purify formaldehyde, while the performance of stems is unclear. A formaldehyde fumigation experiment was conducted on Epipremnum aureum and Rohdea japonica in a sealed chamber. Results showed the stems could remove formaldehyde. The efficiency of removal by the stems of each plant was 0.089 and 0.137 mg∙m⁻³∙h⁻¹, respectively, the rate of purification was 40.0 and 61.6%, respectively. Both were related to plant species and the latter was affected by other factors like exposed area. To further explore the mechanism of phytoremediation, the correlation between the concentration of formaldehyde and CO₂ during the experiment was investigated. Results showed when leaves of plants were exposed to formaldehyde, the concentration of CO₂ increased with the decrease in concentration of formaldehyde, and the change in concentration of CO₂ could be used as an indicator of the degree of decontamination of formaldehyde by the plants.
اظهر المزيد [+] اقل [-]Phytotoxicity of atrazine combined with cadmium on photosynthetic apparatus of the emergent plant species Iris pseudacorus النص الكامل
2022
The combined pollution, instead of single pollution, has become a widespread contamination phenomenon in aquatic environment. However, little information is now available about the joint effects of the combined pollution, especially co-existed pesticides and heavy metals, on aquatic plants. In the present study, using continuous excitation chlorophyll fluorescence parameters and the OJIP transient, comparisons of herbicide atrazine (ATZ) phytotoxicity on Iris pseudacorus between in the presence and absence of cadmium (Cd) were evaluated over an exposure period of three weeks under laboratory conditions. Results showed that both ATZ and Cd were toxic to I. pseudacorus. The ratio Fᵥ/Fₒ, specific electron transport energy (ET₀/RC), and photochemistry efficiency (PIₐbₛ and PIₜₒₜₐₗ) of this emergent plant species at individual ATZ and Cd concentrations were significantly lower than those of the control. ATZ mainly inhibited electron transport beyond QA at PSII acceptor side as indicated by the sharp rise of the J-step level of fluorescence rise kinetics. A pronounced K-step and the loss of I-step due to the damage on the OEC and PSI also occurred when ATZ was at or above 1.0 mg·L⁻¹. In comparison to ATZ alone, ATZ combined with Cd resulted in a lower amplitude rise in J-step with apparent J-I and I-P phases; and significantly lower Fₒ with higher Fᵥ/Fₒ, as well as greater ET₀/RC with higher values of PIₐbₛ and PIₜₒₜₐₗ. However, the adverse influences of ATZ combined with Cd on the above indicators were still significant as compared with the control. Therefore, the coexistence of Cd alleviated the individual phytotoxicities of ATZ, whereas combined pollution of ATZ and Cd still induced the decline in photosynthetic performance of I. pseudacorus, and its potential ecological impacts on the aquatic vegetation cannot be ignored. Our findings offer a better understanding of the joint effects of the pesticide and heavy metal on non-target aquatic plants, and provided valuable insights into the interaction of these pollutants in aquatic environment.
اظهر المزيد [+] اقل [-]Epidemiological characteristics of gonorrhea and its influential meteorological factors: a 14-year retrospective assessment in China النص الكامل
2022
This study aimed to investigate the seasonal variation of gonorrhea in China, and to analyze the relationship between the incidence of gonorrhea and meteorological factors. Data from gonorrhea cases were obtained from the Disease Prevention and Control Bureau and the Data-Center for China Public Health Science, Chinese Center for Disease Control and Prevention, and the incidence of gonorrhea in China from 1 January 2006 to 31 December 2019 was analyzed. Meteorological data from the same period were obtained from the South China Meteorological Data Sharing Center, including the average monthly temperature, relative humidity, atmospheric pressure, sunshine hours, number of rainy days, and precipitation. The ratio-to-moving average method and seasonal subseries plots were used to analyze the seasonality of gonorrhea cases. The distributed lag non-linear model and attribution risks were used to investigate the effects of meteorological indexes on gonorrhea cases. The number of gonorrhea cases showed seasonal variation, with a peak in the third quarter and a decline in the first quarter. The Spearman assay showed that the reported number of patients with gonorrhea was positively correlated with the monthly temperature, relative humidity, precipitation, and number of rainy days. The risk of gonorrhea onset was highest at 6–11 °C, and the highest risk occurred when the average monthly temperature was 7 °C (resulting in an increase of 14.5% compared with 13 °C); a similar result was found regarding the cumulative risk of gonorrhea onset in relation to temperature. The attribution score of temperature to the onset of gonorrhea was 5.02% (95% confidence interval: − 3.84%, 13.88%). The study findings suggest that increased emphasis should be placed on screening for gonorrhea during summer and autumn, and that education on safe sexual behavior should be promoted during these times.
اظهر المزيد [+] اقل [-]Impact of organic amendments on the bioavailability of heavy metals in mudflat soil and their uptake by maize النص الكامل
2022
Organic amendments (OAs) can be a sustainable and effective method for mudflat soil improvement. A field experiment was conducted to investigate the potential of OA application to mudflat soil improvement. We measured the pH, soil organic matter (SOM), salinity, maize growth, and heavy metal (HM) accumulation in OA-applied soils, and maize tissues after three OAs, sewage sludge (SS), Chinese medical residue (CMR), and cattle manure (CM), were applied at the application rates of 0, 30, 75, 150, and 300 t ha⁻¹. OA application significantly increased the SOM and decreased the pH and salinity of mudflat soils. The maize biomass and HM contents in soil and maize increased after OA application. The bioavailability and bioconcentration of HMs were generally in the sequence of SS > CMR > CM. The average bioavailability ratios of HMs were in the order of Cd > Zn > Cu > Mn > Ni. The bioconcentration of Zn and Cd by maize was highest, followed by Mn, Cu, and Ni. SOM, pH, and salinity were the important factors regulating soil available HMs and, subsequently, HM accumulation in maize. Among the three OAs, SS is most effective in decreasing soil salinity, and increasing the SOM, bioavailability, and bioconcentration of HMs. On the other hand, CM was the best OA because it promoted significant maize growth yet maintained low HM contamination risk.
اظهر المزيد [+] اقل [-]A modified exergy evaluation of using carbon-black/water/EG nanofluids as coolant of photovoltaic modules النص الكامل
2022
To provide the progressive global demand for energy, the use of renewable energies is being rapidly developed. Since solar radiation is available in most parts of the earth, the photovoltaic (PV) power plant is one of the worthwhile solutions. As a deficiency, temperature rise in photovoltaic cells leads to a drop in their electrical output power. In this experimental study, the circulation of carbon black nanofluid was investigated as a coolant of PV modules. Both water and ethylene glycol (EG) were used as the base fluids. It is found that all modified cases generate more output power than the conventional one. For instance, water + carbon nanofluid yields 54% more output power compared with the conventional one. To make a real assessment of using nanofluid as a coolant, the electrical consumption by pump and fan must be counted. Therefore, in this study, the net output power is calculated. In the cases of EG and EG + carbon, the net output powers get lower than the conventional module. So, they are not justifiable. In this paper, a modified formula is proposed to calculate the exergy efficiency, in order to achieve more accurate results. Accordingly, from an exergy viewpoint, 16.3% and 4.5% in electrical and thermal exergy efficiencies are achieved, when water + carbon nanofluid was used. Moreover, the values of entropy generation and lost exergy were reported for all considered cases.
اظهر المزيد [+] اقل [-]The effective path of green transformation of heavily polluting enterprises promoted by green merger and acquisition—qualitative comparative analysis based on fuzzy sets النص الكامل
2022
Green merger and acquisition (GMA) is becoming a growing tendency for heavily polluting enterprises in recent years; however, the realization path of green transformation through GMA is still unexplored. Taking 48 Chinese heavily polluting enterprises that had GMA in 2018 as the research object, this paper constructs the “M&A attributes, Organizational characteristics, and External environment” (M-O-E) framework, by using the method of fuzzy-set qualitative comparative analysis (fsQCA) to reveal the configurations of conditions that lead to high levels of green innovation performance. The results show that the high green technology innovation performance after GMA of heavily polluting enterprises is the outcome of multiple antecedents, and no singular antecedent is sufficient for achieving it. Besides, there are three equivalent configurations of conditions to achieve green transformation: professional buyer, internal leading, and internal-external linkage. Among them, the professional buyer configuration highlights that the combination of M&A experience and M&A scale is of great importance, the internal leading configuration emphasizes that the existence of environmental awareness and organizational resources is the core conditions, and the internal-external linkage configuration requires simultaneous efforts of M&A experience and government environmental regulations. Our research contributes to the understanding of green transformation in heavily polluting enterprises from a configurational perspective, and provides a practice-oriented guide to achieve green transformation for the government and heavily polluting enterprises.
اظهر المزيد [+] اقل [-]Highly efficient photocatalytic oxidation of antibiotic ciprofloxacin using TiO2@g-C3N4@biochar composite النص الكامل
2022
Wang, Guanghui | Li, Yingjie | Dai, Jialing | Deng, Nansheng
In this present study, a novel indirect Z-scheme TiO₂@g-C₃N₄@biochar (TiO₂@g-C₃N₄@BC) composite photocatalyst was successfully fabricated and characterized with SEM, TEM, EDS, XRD, FTIR, PL, XPS, and UV–vis DRS. The photocatalytic degradation behavior of ciprofloxacin (CIP) on the TiO₂@g-C₃N₄@BC was evaluated under UV–vis and visible light irradiation, and the possible reaction mechanism of photocatalytic oxidation of CIP on the TiO₂@g-C₃N₄@BC was explained. The TiO₂@g-C₃N₄@BC composite photocatalyst exhibited stronger photocatalytic oxidation activity for CIP in comparison with TiO₂, g-C₃N₄, TiO₂@BC, and TiO₂@g-C₃N₄. After 60 min of UV–vis and visible light irradiation, the photocatalytic removal efficiency of CIP by TiO₂@g-C₃N₄@BC was 99.3 and 89.2%, respectively. The photocatalytic removal performance of CIP was affected by the initial concentration of CIP, catalyst dosage, and pH value. The composite photocatalyst presented excellent stability and reusability after five cycles. An indirect Z-scheme principle of the CIP photocatalytic oxidation reaction on TiO₂@g-C₃N₄@BC was clearly proposed, and the whole process of photocatalytic degradation was the results of the interaction between CIP and reactive active species (·O₂⁻, h⁺, and ·OH), of which ·O₂⁻ is the main active substance. Four CIP degradation pathways were proposed. This work may provide an effective strategy to remove antibiotics in wastewater.
اظهر المزيد [+] اقل [-]The lag effect of 24-year tobacco consumption on lung cancer mortality in Henan Province, China, 1992 to 2016 النص الكامل
2022
Tobacco exposure is the major risk factor for lung cancer. Previous studies have shown that there is a correlation between tobacco consumption and lung cancer mortality, but they do not show a specific trend. This study established the polynomial distributed lags (PDLs) model to explore the distributional lag effect between tobacco consumption and lung cancer mortality by using the lung cancer mortality rate of residents in Henan Province and the annual per capita tobacco consumption data from 1992 to 2016 and adopted dynamic simulation prediction method to predict lung cancer mortality for the next 20 years. We found that per capita tobacco consumption had a 10-year lag effect on lung cancer mortality. The harm of tobacco consumption did not show in the first 4 years, but after a lag of 4 years or more, the lung cancer mortality in men was higher than that in women, with a peak effect occurring 10 years later. The prediction showed that if per capita tobacco consumption was controlled, lung cancer mortality would show a steady decline trend after 10 years. These results suggested that tobacco consumption and lung cancer mortality were asynchronous, with a lag effect of tobacco use on the occurrence of lung cancer.
اظهر المزيد [+] اقل [-]Effects of Different Fertilizers on the Germination of Tomato and Cucumber Seeds النص الكامل
2022
In order to achieve maximum crop yields, the use of fertilizers has become prevalent in the agricultural industry. Chemical fertilizers are a controversial topic where the accumulation of heavy metals is detrimental to soil conditions, as well as in water and air pollution. However, there is little information from investigations on the effectiveness of different fertilizers on seed germination. This study evaluated six fertilizers: three organic fertilizers, namely fish manure (FM), bone meal (BM), and seaweed meal (SM), and three inorganic fertilizers, namely urea, HYPONeX NO.40 (HPX), and potassium sulfate (PS), on seed germination and root and shoot elongation in tomatoes and cucumbers. BM was regarded as the most effective fertilizer with the highest germination shown in tomato and cucumber crops. The results show that the six tested fertilizers promoted higher root and shoot elongations. The optimal concentration was identified in dosages at 100 mg/L with the application of FM, BM, HPX, and PS. For urea and SM, the most effective concentrations were 150 mg/L and more than 200 mg/L, respectively. Furthermore, the regression equations indicated there was a strong correlation between N, P, and K provided in the fertilizers and the growth performance, where the R² ranged from 0.76 to 0.99. The use of FM had a strong correlation with growth performance, which reflected that the levels of FM (9.5:3:0.4) were effective to sustain the growth of tomato and cucumber seedlings. The study suggested that organic fertilizers could be the most applicable and should be widely used in the agricultural industry, as the seed germination rates and root and shoot elongations were observed high. These fertilizers would lessen the impacts on the environment.
اظهر المزيد [+] اقل [-]Increase of antibiotic resistance genes via horizontal transfer in single- and two-chamber microbial electrolysis cells النص الكامل
2022
Microbial electrolysis cells (MECs) have been applied for antibiotic degradation but simultaneously induced antibiotic resistance genes (ARGs), thus representing a risk to disseminate antibiotic resistance. However, few studies were on the potential and risk of ARGs transmission in the MECs. This work assessed conjugative transfer of ARGs under three tested conditions (voltages, cell concentration, and donor/recipient ratio) in both single- and two-chamber MECs. The results indicated that voltages (> 0.9 V) facilitated the horizontal frequency of ARGs in the single-chamber MECs and anode chamber of two-chamber MECs. The donor cell number (donor/recipient ratio was 2:1) increased the transfer frequency of ARGs. Furthermore, voltages ranged from 0.9 to 2.5 V increased reactive oxygen species (ROS) production and cell membrane permeability in MECs. These findings offer new insights into the roles of ARG transfer under different applied voltages in the MECs, which should not be ignored for horizontal transfer of antibiotic resistance.
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