Abandoned chemical smelting sites containing toxic substances can seriously threaten and pose a risk to the surrounding ecological environment.Soil samples were collected from different depths(0 to 13 m)and analyzed f...Abandoned chemical smelting sites containing toxic substances can seriously threaten and pose a risk to the surrounding ecological environment.Soil samples were collected from different depths(0 to 13 m)and analyzed for metal(loid)s content and fractionation,as well as microbial activities.The potential ecological risk indices for the different soil depths(ordered from high to low)were:1 m(D-1)>surface(S-0)>5 m(D-5)>13 m(D-13)>9 m(D-9),ranging between 1840.65-13,089.62,and representing extremely high environmental risks,of which Cd(and probably not arsenic)contributed to the highest environmental risk.A modified combined pollution risk index(MCR)combining total content and mobile proportion of metal(loid)s,and relative toxicities,was used to evaluate the degree of contamination and potential environmental risks.For the near-surface samples(S-0 and D-1 layers),the MCR considered that As,Cd,Pb,Sb,and Zn achieved high and alarming degrees of contamination,whereas Fe,Mn,and Ti were negligible or low to moderate pollution degrees.Combined microcalorimetry and enzymatic activity measurements of contaminated soil samples were used to assess the microbial metabolic activity characteristics.Correlation analysis elucidated the relationship between metal(loid)s exchangeable fraction or content and microbial activity characteristics(p<0.05).The microbial metabolic activity in the D-1 layer was low presumably due to heavy metal stress.Enzyme activity indicators and microcalorimetric growth rate(k)measurements were considered sensitive indicators to reflect the soil microbial activities in abandoned chemical smelting sites.展开更多
Synthetic pyrethroids （SPs） are among the most common pesticides in current use, and so far, several SPs have been assessed for their potential estrogenicities by various methods. Previous studies have shown that th...Synthetic pyrethroids （SPs） are among the most common pesticides in current use, and so far, several SPs have been assessed for their potential estrogenicities by various methods. Previous studies have shown that the estrogenicities partly come from their metabolites. Although considerable information is available with respect to the metabolism and environmental degradation of SPs, little is known about the estrogenicities of the metabolites. In this study, permethrin （PM） and β-cypermethrin （CP）, as well as their metabolites （3-phenoxybenzoic alcohol （PBCOH）, 3-phenoxybenzaldehyde （PBCHO） and 3-phenoxybenzoic acid （PBCOOH） were evaluated for their estrogenic activities in the MCF-7 human breast carcinoma cell line. In the MCF-7 cell proliferation assay, PM and CP exhibited significant estrogenic activities at 10-7 mol/L, comparable to 17β-estradiol （E2） of 10-9 tool/L, with the relative proliferative effect ratios of 55.4% and 56.3%, respectively. The real-time quantitative polymerase chain reaction （qRT-PCR） results confirmed the estrogenicities of PM and CP with significant alteration of pS2 and ERα mRNA levels observed at 10-6 mol/L. For the three major metabolites, PBCOH and PBCOOH exhibited estrogenic activities in all assays, while no significant estrogenic responses was observed for PBCHO compared to the vehicle control. In particular, PBCOH had even slightly stronger estrogenic activity than its parent compounds, indicating that metabolism may be one of the reasons for the estrogenicities of the SPs. Given the widespread use of SPs, the toxicological effects of parent compounds and their metabolites should be taken into consideration in the risk assessment of SPs.展开更多
Persulfate activation has been applied as one of the efficient advanced oxidation processes(AOPs) to remediate polluted environments. In this study, a novel α-FeOOH anchored by graphene oxide(GO)-carbon nanotubes(CNT...Persulfate activation has been applied as one of the efficient advanced oxidation processes(AOPs) to remediate polluted environments. In this study, a novel α-FeOOH anchored by graphene oxide(GO)-carbon nanotubes(CNTs) aerogel(α-FeOOH@GCA) nanocomposite activated persulfate system(α-FeOOH@GCA + K2S2O8) was applied for decolorization of Orange Ⅱ(OⅡ). The decolorization of OⅡ was remarkably enhanced to a level of ~ 99% in this system compared with that of pristine α-FeOOH(~ 44%) or GO-CNTs(~18%). The enhanced catalytic activity of α-FeOOH@GCA was due to the formation of a heterojunction byα-FeOOH and GO-CNTs as confirmed by the presence of Fe–O–C chemical bonds. The degradation intermediates of OⅡ were comprehensively identified. The proposed degradation pathway of OⅡ begins with the destruction of the conjugated structures of OⅡ by the dominant reactive oxygen species, surface-bound SO4·-. The decolorization efficiency of OⅡ by the α-FeOOH@GCA activated persulfate system decreased from the first to third cycle of recycling. Ultraviolet(UV) irradiation or introduction of a small amount of Fe2+ could restore the activation of this system. The results show that the α-FeOOH@GCA persulfate activation system promises to be a highly efficient environmental remediation method for organic pollutants.展开更多
In a non-chiral environment, the enantiomers of a racemate possessed the identical physico-cbemical properties, but in the biological systems they possessed different activities. Considering that the involvement of ox...In a non-chiral environment, the enantiomers of a racemate possessed the identical physico-cbemical properties, but in the biological systems they possessed different activities. Considering that the involvement of oxidative damage has been implicated in the toxicities of various pesticides, this study investigated the possibility of enantioselective oxidative stress and cytotoxicity induction by acetofenate （AF） which contains an asymmetrical center on PC12 cells. The results of the cytotoxicity assay indicated that S-（＋）-AF presented more toxic effects than R-（-）-AF and （＋）-AF. It also demonstrated that S-（＋）-AF possessed the strongest effects in induction of reactive oxygen species （ROS） production, decrease in superoxide dismutase （SOD） and catalase （CAT） activities, and increase in malondialdehyde （MDA） level. These results suggested that AF and its enanfiomers could induce enantioselecfive cytotoxicity in PC12 cells mediated by oxidative stress. Therefore, the assessment in environmental safety and new chiral pesticide development should consider enantioselectivity.展开更多
In this study, the performance of a sequencing batch biofilm reactor(SBBR) for removal of nitrogen and phosphorus from swine wastewater was evaluated. The replacement rate of wastewater was set at 12.5% throughout the...In this study, the performance of a sequencing batch biofilm reactor(SBBR) for removal of nitrogen and phosphorus from swine wastewater was evaluated. The replacement rate of wastewater was set at 12.5% throughout the experiment. The anaerobic and aerobic times were 3 h and 7 h, respectively, and the dissolved oxygen concentration of the aerobic phase was about 3.95 mg·L-1. The SBBR process demonstrated good performance in treating swine wastewater. The percentage removal of total chemical oxygen demand(COD), ammonia nitrogen(NH4+-N), total nitrogen(TN), and total phosphorus(TP) was 98.2%, 95.7%, 95.6%, and 96.2% at effluent concentrations of COD85.6 mg·L-1, NH4+-N 35.22 mg·L-1, TN 44.64 mg·L-1, and TP 1.13 mg·L-1, respectively. Simultaneous nitrification and denitrification phenomenon was observed. Further improvement in removal efficiency of NH4+-N and TN occurred at COD/TN ratio of 11:1, with effluent concentrations at NH4+-N 18.5 mg·L-1and TN 34 mg·L-1, while no such improvement in COD and TP removal was found. Microbial electron microscopy analysis showed that the filler surface was covered with a thick biofilm, forming an anaerobic–aerobic microenvironment and facilitating the removal of nitrogen, phosphorus and organic matters. A long-term experiment(15 weeks) showed that stable removal efficiency for N and P could be achieved in the SBBR system.展开更多
Climate change is thought to have a greater impact on crops that require particular conditions for their productivity.Southwest Ethiopia is a region where important cash crops such as Coffea arabica and Aframomum corr...Climate change is thought to have a greater impact on crops that require particular conditions for their productivity.Southwest Ethiopia is a region where important cash crops such as Coffea arabica and Aframomum corrorima(korerima)originate.These crops are known to require shade for their growth and productivity.This study was conducted to assess the impacts of climate change on an important but neglected cash crop of A.corrorima using GIS-based species distribution approaches.Local meteorological data and bioclimatic data from WorldClim were used to map past,present,and future distribution of the crop in the Coffee Forest System of Southwest Ethiopia.Moreover,96 key informants were interviewed and completed questionnaires to complement the distribution modeling.The key informants mapped the history and present occurrences of A.corrorima and based on this,ground-truthing survey was conducted.The interpolation method of the Inverse Distance Weighted was used in ArcGIS 10.5 to develop bioclimatic variables for modeling past and present distribution while data from IPCC(AR4)Emissions Scenarios was used for the future occurrence prediction using Principal Component Analysis.Eleven best bioclimatic variables were selected and MaxEnt was used to model past,present and future distribution of A.corrorima.The output of our model was validated using Area Under the Curve(AUC)approach.Temperature and precipitation are the most important environmental variable,then temperature increased by 1.3°C in the past(from 1988 to 2018)while it is predicted to increase further by at least 1.4°C before 2050.On the contrary,precipitation decreased by an average of 10.1 mm from the past while it is predicted to decrease further by 12.5 mm before 2050.Our model shows that the area suitable for korerima in 1988 was 20,638.2 ha and it was reduced by half and became 10,545.3 ha in 2018,similarly predicted to shrink into 3225.5 ha by 2050.The findings from the key informants confirm the model results whereby 89.1%of the respondent replied korerima producing area has been shifted into the mountains over the last 30 years(by 150 m a.s.l.from 1988 to 2018)and thus expected to be pushing up in the next 32 years(by 133 m before 2050).The community claims that the length of the rainy season of the area has been shortening from 9 months in the past to an average of 5.5 months recently which also coincides with increasing temperature.We conclude that with the changing climatic condition,the suitable habitat of korerima has already shrank by 48.9%(from 1988 to 2018)and the trend may lead to a shrink by 84.38%before 2050(from 1988 to 2050).Therefore,it is important to develop site-specific climate adaptation strategies for the region such as promoting alternative livelihoods and avoiding further coffee forest degradation and deforestation.展开更多
Photocatalytic selective transform native lignin into valuable chemicals is an attractive but challenging task.Herein,we report a mesoporous sulfur-doped carbon nitride(MSCN-0.5)which is prepared by a facile one-step ...Photocatalytic selective transform native lignin into valuable chemicals is an attractive but challenging task.Herein,we report a mesoporous sulfur-doped carbon nitride(MSCN-0.5)which is prepared by a facile one-step thermal condensation strategy.It is highly active and selective for the cleavage Cα-Cβbond inβ-O-4 lignin model compound under visible light radiation at room temperature,achieving 99%substrate conversion and 98%Cα-Cβbond cleavage selectivity.Mechanistic studies revealed that the Cβ-H bond of lignin model compounds activated by holes and generate key Cβradical intermediates,further induced the Cα-Cβbond cleavage by superoxide anion radicals(·O2-)to produce aromatic oxygenates.Waste Camellia oleifera shell(WCOS)was taken as a representative to further understand the reaction mechanisms on native lignin.33.2 mg of monophenolic compounds(Vanillin accounted for 22%and Syringaldehyde for 34%)can be obtained by each gram of WCOS lignin,which is 2.5 times as that of the pristine carbon nitride.The present work offers useful guidance for designing metal-free heterogeneous photocatalysts for Cα-Cβbond cleavage to harvest monophenolic compounds.展开更多
The effects of Rare Earth Element Lan on the activities of cellulose, catalase, peroxidase and superoxide dismutasein in earthworm were carried out by natural soil test. The results indicated that Lan can significantl...The effects of Rare Earth Element Lan on the activities of cellulose, catalase, peroxidase and superoxide dismutasein in earthworm were carried out by natural soil test. The results indicated that Lan can significantly suppress the activity of cellulose. The responses of three enzymes in earthworm to Lan were different, Lan mostly affects catalase activity and inhibited catalase activity throughout the experiment. Peroxidase activity tend to 'promote weakly and inhibited strongly' when short term of exposure to Lan, while 'inhibited weakly and promote strongly' as a function of time. In comparison, Lan had little influence on the activity of superoxide dismutase. The variance analysis results showed that the concentration of Lan significantly affected the activities of cellulose and CAT but had no obvious influence on the activities of SOD and POD. The treatment time and the interactive effect between treatment concentrations and time had very significant effect on the activities of cellulose, SOD, CAT and POD.展开更多
The effects of silver sulfide (Ag 2S) on the bioleaching of chalcopyrite and pyrite were investigated in this paper. It has been shown that Ag 2S enhanced the yields of bioleaching of chalcopyrite but inhibited the bi...The effects of silver sulfide (Ag 2S) on the bioleaching of chalcopyrite and pyrite were investigated in this paper. It has been shown that Ag 2S enhanced the yields of bioleaching of chalcopyrite but inhibited the bio oxidation of pyrite. The addition of Ag 2S selectively increased the copper dissolution from the chalcopyrite containing ores in shake flasks with a recovery of 85.3% compared with 24.3% without Ag 2S, while slightly decreased the iron yields from 51% to 41.8%. The copper extraction of the chalcoopyrite containing waste rock in column leaching charged with 18 kg mass increased up to 21.7% in the presence of Ag 2S, while only 3.4% in the absence of the catalyst. The mechanism of Ag 2S catalysis could be explained well by the "Mixed potential model".展开更多
Comparative study on the activity and kinectic properties of acid phosphatase （ACPase） of three soils amended with Hg and Cu at constant temperature and humidity was carried out. The results indicated that the inhib...Comparative study on the activity and kinectic properties of acid phosphatase （ACPase） of three soils amended with Hg and Cu at constant temperature and humidity was carried out. The results indicated that the inhibition on ACPase of the three sample soils by Hg and Cu varied with the content of soil organic matter and pH, where, Soil 1 was the most seriously contaminated due to its lowest content of organic matter and the lowest pH among three samples, Soil 2 took the second place, and Soil 3 was the least contaminated. Except Soil 3, the activity of soil ACPase tended to increase along with the contact time under the same type and the same concentration of heavy metal. In particular the Vmax values of ACPase in all three samples decreased with increasing Hg and Cu concentration, whereas the Km values were affected weakly. According to the change of Vmax and Km values, Cu and Hg had the same inhibition effect on soil ACPase. Both of them may he a type of compound of non-competitive and anti-competitive inhibition. Statistic analyses indicated that activities of soil ACPase and Vmax values could serve as bioindicator to partially denote the heavy metal Hg and Cu contamination degree.展开更多
The interaction of the novel tetra-carboxylphenyl calix[4]arene （TCPC） with the bovine heart cytochrome c （Cc） was first investigated by fluorescence spectroscopy and molecular modeling methods. The formation of a...The interaction of the novel tetra-carboxylphenyl calix[4]arene （TCPC） with the bovine heart cytochrome c （Cc） was first investigated by fluorescence spectroscopy and molecular modeling methods. The formation of a stable 1：1 complex was monitored by fluorescence titration, and its binding constant is 1.916 ×10^7 L mol^-1. Molecular modeling reveals the recognition mechanism of TCPC to the Cc surface, that is, the electrostatic interaction drives TCPC to the Cc surface, and the van der Waals interaction orientates TCPC parallel to the cleft of Cc.展开更多
Species composition,structure,regeneration,and management status of Jorgo-Wato Forest(JWF)was studied.Number of individuals,diameter at breast height(dbh)and height of woody species(dbh≥2.5 cm)were counted and measur...Species composition,structure,regeneration,and management status of Jorgo-Wato Forest(JWF)was studied.Number of individuals,diameter at breast height(dbh)and height of woody species(dbh≥2.5 cm)were counted and measured in each plot.Group discussions with local farmers residing around JWF were carried out to understand the management of the JWF.Forest structural attributes were computed using descriptive statistics;correlation was used to assess relationships between the structural variables.A total of 4313 individuals(dbh≥2.5 cm)with a density of 1477 ha-1 were recorded,the number of species and individuals decreasing with increasing dbh classes.Species with the highest Importance Value Index(IVI)were Pouteria adolfifriedericii(37.7),Syzygium guineense subsp.afromontanum(23.6),Dracaena afromontana(20.5),Chionanthus mildbraedii(15.9),and Croton macrostachyus(12.3).Overall distribution of woody plants across size classes exhibited a reverse J-pattern,suggesting a healthy population structure and good regeneration.Nevertheless,some species were not represented in smaller diameter classes,including juvenile phases,which indicate a lack of regeneration.For these species,monitoring and enrichment planting would be necessary,along with curbing illegal cutting and coffee farming in the natural forest.Management interventions in the JWF need to consider livelihood options and to respect the rights of local communities.展开更多
A novel potassium ions sensor based on mode-filtered light detection was reported. The analyzer was consisting of an optical fiber immobilized with a dye of bromocresol green and a fused-silica capillary. It was found...A novel potassium ions sensor based on mode-filtered light detection was reported. The analyzer was consisting of an optical fiber immobilized with a dye of bromocresol green and a fused-silica capillary. It was found that mode-filtered light intensity decreased with the concentration of potassium ions and a linear detection range of 0.25-20 mmol/L （R^2 = 0.9977） was obtained with a detection limit of 9 ×10^-5 mol/L as well as fast response, good reproducibility and reversibility in the working concentration range.展开更多
The interaction of calf thymus DNA（ctDNA） with berberine（Ber） was systematically investigated via UV-Vis,fluorescence and phosphorescence spectroscopies in aqueous solution and on solid substrate.The very weak flu...The interaction of calf thymus DNA（ctDNA） with berberine（Ber） was systematically investigated via UV-Vis,fluorescence and phosphorescence spectroscopies in aqueous solution and on solid substrate.The very weak fluorescence intensity of Ber at 525 nm in aqueous solution can be greatly enhanced by ctDNA.The UV-Vis spectrum shows that Ber could bind with DNA by intercalation.In addition,strong fluorescence of Ber alone could be observed on filter paper substrate and can be quenched by ctDNA effectively,and the increase of fluorescence polarization of Ber on the filter paper implies the intercalation binding.Ber emits phosphorescence at 619 nm in the presence of thallium（I） acetate.The lifetime of Ber increased from 38.4 ms to 43.4 ms with the increase of ctDNA.The increase of lifetime is possibly attributed to the increase of rigidity of Ber after its intercalating into the ctDNA base pairs.This explanation is also augmented by the anionic quenching results.Ber behaves as a typical intercalating agent into ctDNA.The intrinsic binding constant between Ber and ctDNA is（1.84±0.12）×10^4 L/mol and n=0.16.展开更多
The size distribution of fragmented rocks depends on not only the blasting standard but also the mechanical properties, joint system and crack density of rock mass. As, especially, the cracks in the rock mass are heav...The size distribution of fragmented rocks depends on not only the blasting standard but also the mechanical properties, joint system and crack density of rock mass. As, especially, the cracks in the rock mass are heavily developed at the limestone quarries in Japan, the joints and/or cracks in the rock mass have big impacts on the blasting effects such as the size of fragmented rocks. Therefore, if the joint system and/or crack density in the rock mass can be known and evaluated in quantity, the blasting operation can be done more effectively, efficiency and safety. However, the guideline for designing the appropriate blasting standard based on the rock mass condition such as mechanical properties, joint system and/or distribution of cracks, discontinuities, from the scientific point of view, has not been developed yet. Therefore, a series of blasting tests had been conducted in different mines and faces, geological conditions and blasting standards in order to know the impacts of each factor on the blasting effects. This paper summarizes the results of blasting tests and describes the impacts of rock mass conditions and blasting standard on the size of fragmented rocks.展开更多
Morin (MR) is an anticancer drug present in fruits and Chinese herbs. Fe3O4 magnetic nanoparticles (MNPs) coated on 3-aminopropyl triethoxysilane (APTES) were synthesized (MNPs-APTES) as carriers for MR. The character...Morin (MR) is an anticancer drug present in fruits and Chinese herbs. Fe3O4 magnetic nanoparticles (MNPs) coated on 3-aminopropyl triethoxysilane (APTES) were synthesized (MNPs-APTES) as carriers for MR. The characterization of drug delivery system was confirmed by Fourier Transform Infrared (FTIR), Transmission Electron Microscope (TEM), X-Ray Diffraction (XRD), dynamic light scattering (DLS), and vibrating sample magnetometer (VSM). The adsorbed APTES on the magnetite surface (MNPs-APTES) was examined by FTIR. The TEM image showed that the average particle size is obtained to be about 26.7 nm for MNPs-APTES. The MR loading and release behavior of MNPs-APTES were studied and the results showed that up to 60% of the adsorbed drug was released within 4 h. In summary, the MNPs-APTES nanocarriers are based on the results, promising for targeted morin drug delivery.展开更多
The main objective of this research work was to diagnose the vulnerability of terrestrial ecosystems to S deposition in Atasta region in Campeche State, Mexico, comprising two simultaneous sampling programs in both, s...The main objective of this research work was to diagnose the vulnerability of terrestrial ecosystems to S deposition in Atasta region in Campeche State, Mexico, comprising two simultaneous sampling programs in both, soil and atmospheric deposition on an annual basis during three climatic periods: dry, rainy and cold fronts seasons. From the estimation of soil properties estimation (pH, texture, mineralogy, cationic exchange capacity, and basis saturation %), critical loads and sensitivity classes were assigned to sampled soils based according to the empirical methodology proposed by UNECE. During the dry season, 10 sites fell into sensitivity class 2 (moderately sensitive) and 3 (sensitive). On the other hand, during the rainy season, 8 sites showed a sensitivity class 1 (highly sensitive) and 2 sites presented a sensitivity class 2 (moderately sensitive);whereas along cold fronts season, 12 sites fell into sensitivity class 1 that corresponds to highly sensitive. Sensitivity classes showed a seasonal trend, with a higher sensitivity during rainy and cold fronts seasons;this agrees with the kind of sources influencing on the study area as a result of the prevailing meteorology during these climatic periods. Likewise, S concentration in atmospheric deposition was determined by turbidimetric method, and S deposition fluxes were estimated from surface area of the funnel opening of the sampling device and the sampling period. S deposition fluxes ranged from 0.29 and 14.06 kg S ha-1·yr-1;with a mean value of 8.57 kg S ha-1·yr-1. From the comparison between the current deposition rates and proposed critical loads, exceedances percentages were obtained (from 1.65% to 62.8%) and mapped to identify critical zones of S deposition in the studied area. It was established the important role which mangrove vegetation plays in the attenuation of the potential ecological effects on terrestrial ecosystems of the study area associated to atmospheric deposition.展开更多
Plasma treatment is necessary to optimize the performance of biomaterial surfaces.It enhances and regulates the performance of biomaterial su rfaces,creating an effective interface with the human body.Plasma treatment...Plasma treatment is necessary to optimize the performance of biomaterial surfaces.It enhances and regulates the performance of biomaterial su rfaces,creating an effective interface with the human body.Plasma treatments have the ability to modify the chemical com position and physical structu re of a surface while leaving its properties unaffected.They possess the ability to modify material su rfaces,eliminate contaminants,conduct investigations on cancer therapy,and facilitate wound healing.The subject of study in question involves the integration of plasma science and technology with biology and medicine.Using a helium plasma jet source,applying up to 18 kV,with an average power of 10 W,polymer foils were treated for 60 s.Plasma treatment has the ability to alter the chemical composition and physical structure of a su rface while maintaining its quality.This investigation involved the application of helium plasma at atmospheric pressure to polyamide 6 and polyethylene terephthalate sheets.The inquiry involves monitoring and assessing the plasma source and polymer materials,as well as analyzing the impacts of plasma therapy.Calculating the mean power of the discharge aids in assessing the economic efficacy of the plasma source.Electric discharge in helium at atmospheric pressure has beneficial effects in technology,where it increases the surface free energy of polymer materials.In biomedicine,it is used to investigate cytotoxicity and cell survival,particularly in direct blood exposure situations that can expedite coagulation.Comprehending the specific parameters that influence the plasma source in the desired manner for the intended application is of utmost im portance.展开更多
基金supported by the National Key Research and Development Program of China(No.2019YFC1803500)the National Natural Science Foundation of China(No.42230716)+3 种基金the National Natural Science Foundation of China(No.42007289)the 111 Project(No.B21017)the Centre National de la Recherche Scientifique(No.CNRS PRC1416,France)the 1000-Talents Plan project(No.WQ2017110423)。
文摘Abandoned chemical smelting sites containing toxic substances can seriously threaten and pose a risk to the surrounding ecological environment.Soil samples were collected from different depths(0 to 13 m)and analyzed for metal(loid)s content and fractionation,as well as microbial activities.The potential ecological risk indices for the different soil depths(ordered from high to low)were:1 m(D-1)>surface(S-0)>5 m(D-5)>13 m(D-13)>9 m(D-9),ranging between 1840.65-13,089.62,and representing extremely high environmental risks,of which Cd(and probably not arsenic)contributed to the highest environmental risk.A modified combined pollution risk index(MCR)combining total content and mobile proportion of metal(loid)s,and relative toxicities,was used to evaluate the degree of contamination and potential environmental risks.For the near-surface samples(S-0 and D-1 layers),the MCR considered that As,Cd,Pb,Sb,and Zn achieved high and alarming degrees of contamination,whereas Fe,Mn,and Ti were negligible or low to moderate pollution degrees.Combined microcalorimetry and enzymatic activity measurements of contaminated soil samples were used to assess the microbial metabolic activity characteristics.Correlation analysis elucidated the relationship between metal(loid)s exchangeable fraction or content and microbial activity characteristics(p<0.05).The microbial metabolic activity in the D-1 layer was low presumably due to heavy metal stress.Enzyme activity indicators and microcalorimetric growth rate(k)measurements were considered sensitive indicators to reflect the soil microbial activities in abandoned chemical smelting sites.
基金supported by the National Basic Research of China (No.2009CB421603)the National Natural Science Foundations of China (No.20837002,20877071)
文摘Synthetic pyrethroids （SPs） are among the most common pesticides in current use, and so far, several SPs have been assessed for their potential estrogenicities by various methods. Previous studies have shown that the estrogenicities partly come from their metabolites. Although considerable information is available with respect to the metabolism and environmental degradation of SPs, little is known about the estrogenicities of the metabolites. In this study, permethrin （PM） and β-cypermethrin （CP）, as well as their metabolites （3-phenoxybenzoic alcohol （PBCOH）, 3-phenoxybenzaldehyde （PBCHO） and 3-phenoxybenzoic acid （PBCOOH） were evaluated for their estrogenic activities in the MCF-7 human breast carcinoma cell line. In the MCF-7 cell proliferation assay, PM and CP exhibited significant estrogenic activities at 10-7 mol/L, comparable to 17β-estradiol （E2） of 10-9 tool/L, with the relative proliferative effect ratios of 55.4% and 56.3%, respectively. The real-time quantitative polymerase chain reaction （qRT-PCR） results confirmed the estrogenicities of PM and CP with significant alteration of pS2 and ERα mRNA levels observed at 10-6 mol/L. For the three major metabolites, PBCOH and PBCOOH exhibited estrogenic activities in all assays, while no significant estrogenic responses was observed for PBCHO compared to the vehicle control. In particular, PBCOH had even slightly stronger estrogenic activity than its parent compounds, indicating that metabolism may be one of the reasons for the estrogenicities of the SPs. Given the widespread use of SPs, the toxicological effects of parent compounds and their metabolites should be taken into consideration in the risk assessment of SPs.
基金supported by China’s National Science Foundation(No.21377039)
文摘Persulfate activation has been applied as one of the efficient advanced oxidation processes(AOPs) to remediate polluted environments. In this study, a novel α-FeOOH anchored by graphene oxide(GO)-carbon nanotubes(CNTs) aerogel(α-FeOOH@GCA) nanocomposite activated persulfate system(α-FeOOH@GCA + K2S2O8) was applied for decolorization of Orange Ⅱ(OⅡ). The decolorization of OⅡ was remarkably enhanced to a level of ~ 99% in this system compared with that of pristine α-FeOOH(~ 44%) or GO-CNTs(~18%). The enhanced catalytic activity of α-FeOOH@GCA was due to the formation of a heterojunction byα-FeOOH and GO-CNTs as confirmed by the presence of Fe–O–C chemical bonds. The degradation intermediates of OⅡ were comprehensively identified. The proposed degradation pathway of OⅡ begins with the destruction of the conjugated structures of OⅡ by the dominant reactive oxygen species, surface-bound SO4·-. The decolorization efficiency of OⅡ by the α-FeOOH@GCA activated persulfate system decreased from the first to third cycle of recycling. Ultraviolet(UV) irradiation or introduction of a small amount of Fe2+ could restore the activation of this system. The results show that the α-FeOOH@GCA persulfate activation system promises to be a highly efficient environmental remediation method for organic pollutants.
基金supported by the National Basic Research Program(973) of China (No. 2009CB421603)the National Natural Science Foundations of China(No.20877071)the International Cooperation Project of Wenzhou City(No. H20090023)
文摘In a non-chiral environment, the enantiomers of a racemate possessed the identical physico-cbemical properties, but in the biological systems they possessed different activities. Considering that the involvement of oxidative damage has been implicated in the toxicities of various pesticides, this study investigated the possibility of enantioselective oxidative stress and cytotoxicity induction by acetofenate （AF） which contains an asymmetrical center on PC12 cells. The results of the cytotoxicity assay indicated that S-（＋）-AF presented more toxic effects than R-（-）-AF and （＋）-AF. It also demonstrated that S-（＋）-AF possessed the strongest effects in induction of reactive oxygen species （ROS） production, decrease in superoxide dismutase （SOD） and catalase （CAT） activities, and increase in malondialdehyde （MDA） level. These results suggested that AF and its enanfiomers could induce enantioselecfive cytotoxicity in PC12 cells mediated by oxidative stress. Therefore, the assessment in environmental safety and new chiral pesticide development should consider enantioselectivity.
基金Supported by the Beijing Municipal Science and Technology Program(Z121100001512008)
文摘In this study, the performance of a sequencing batch biofilm reactor(SBBR) for removal of nitrogen and phosphorus from swine wastewater was evaluated. The replacement rate of wastewater was set at 12.5% throughout the experiment. The anaerobic and aerobic times were 3 h and 7 h, respectively, and the dissolved oxygen concentration of the aerobic phase was about 3.95 mg·L-1. The SBBR process demonstrated good performance in treating swine wastewater. The percentage removal of total chemical oxygen demand(COD), ammonia nitrogen(NH4+-N), total nitrogen(TN), and total phosphorus(TP) was 98.2%, 95.7%, 95.6%, and 96.2% at effluent concentrations of COD85.6 mg·L-1, NH4+-N 35.22 mg·L-1, TN 44.64 mg·L-1, and TP 1.13 mg·L-1, respectively. Simultaneous nitrification and denitrification phenomenon was observed. Further improvement in removal efficiency of NH4+-N and TN occurred at COD/TN ratio of 11:1, with effluent concentrations at NH4+-N 18.5 mg·L-1and TN 34 mg·L-1, while no such improvement in COD and TP removal was found. Microbial electron microscopy analysis showed that the filler surface was covered with a thick biofilm, forming an anaerobic–aerobic microenvironment and facilitating the removal of nitrogen, phosphorus and organic matters. A long-term experiment(15 weeks) showed that stable removal efficiency for N and P could be achieved in the SBBR system.
基金the Tapi Spice Research Center for their support。
文摘Climate change is thought to have a greater impact on crops that require particular conditions for their productivity.Southwest Ethiopia is a region where important cash crops such as Coffea arabica and Aframomum corrorima(korerima)originate.These crops are known to require shade for their growth and productivity.This study was conducted to assess the impacts of climate change on an important but neglected cash crop of A.corrorima using GIS-based species distribution approaches.Local meteorological data and bioclimatic data from WorldClim were used to map past,present,and future distribution of the crop in the Coffee Forest System of Southwest Ethiopia.Moreover,96 key informants were interviewed and completed questionnaires to complement the distribution modeling.The key informants mapped the history and present occurrences of A.corrorima and based on this,ground-truthing survey was conducted.The interpolation method of the Inverse Distance Weighted was used in ArcGIS 10.5 to develop bioclimatic variables for modeling past and present distribution while data from IPCC(AR4)Emissions Scenarios was used for the future occurrence prediction using Principal Component Analysis.Eleven best bioclimatic variables were selected and MaxEnt was used to model past,present and future distribution of A.corrorima.The output of our model was validated using Area Under the Curve(AUC)approach.Temperature and precipitation are the most important environmental variable,then temperature increased by 1.3°C in the past(from 1988 to 2018)while it is predicted to increase further by at least 1.4°C before 2050.On the contrary,precipitation decreased by an average of 10.1 mm from the past while it is predicted to decrease further by 12.5 mm before 2050.Our model shows that the area suitable for korerima in 1988 was 20,638.2 ha and it was reduced by half and became 10,545.3 ha in 2018,similarly predicted to shrink into 3225.5 ha by 2050.The findings from the key informants confirm the model results whereby 89.1%of the respondent replied korerima producing area has been shifted into the mountains over the last 30 years(by 150 m a.s.l.from 1988 to 2018)and thus expected to be pushing up in the next 32 years(by 133 m before 2050).The community claims that the length of the rainy season of the area has been shortening from 9 months in the past to an average of 5.5 months recently which also coincides with increasing temperature.We conclude that with the changing climatic condition,the suitable habitat of korerima has already shrank by 48.9%(from 1988 to 2018)and the trend may lead to a shrink by 84.38%before 2050(from 1988 to 2050).Therefore,it is important to develop site-specific climate adaptation strategies for the region such as promoting alternative livelihoods and avoiding further coffee forest degradation and deforestation.
基金finacially supported by the National Natural Science Foundation of China(Nos.21966023,21665018 and 51568049)the Natural Science Foundation of Jiangxi Province,China(No.20171ACB21035)Jiangxi Province Graduate Student Innovation Special Fund(No.YC2020-S513)。
文摘Photocatalytic selective transform native lignin into valuable chemicals is an attractive but challenging task.Herein,we report a mesoporous sulfur-doped carbon nitride(MSCN-0.5)which is prepared by a facile one-step thermal condensation strategy.It is highly active and selective for the cleavage Cα-Cβbond inβ-O-4 lignin model compound under visible light radiation at room temperature,achieving 99%substrate conversion and 98%Cα-Cβbond cleavage selectivity.Mechanistic studies revealed that the Cβ-H bond of lignin model compounds activated by holes and generate key Cβradical intermediates,further induced the Cα-Cβbond cleavage by superoxide anion radicals(·O2-)to produce aromatic oxygenates.Waste Camellia oleifera shell(WCOS)was taken as a representative to further understand the reaction mechanisms on native lignin.33.2 mg of monophenolic compounds(Vanillin accounted for 22%and Syringaldehyde for 34%)can be obtained by each gram of WCOS lignin,which is 2.5 times as that of the pristine carbon nitride.The present work offers useful guidance for designing metal-free heterogeneous photocatalysts for Cα-Cβbond cleavage to harvest monophenolic compounds.
基金Project supported bythe National Natural Science Foundation of China (2002CB410800)
文摘The effects of Rare Earth Element Lan on the activities of cellulose, catalase, peroxidase and superoxide dismutasein in earthworm were carried out by natural soil test. The results indicated that Lan can significantly suppress the activity of cellulose. The responses of three enzymes in earthworm to Lan were different, Lan mostly affects catalase activity and inhibited catalase activity throughout the experiment. Peroxidase activity tend to 'promote weakly and inhibited strongly' when short term of exposure to Lan, while 'inhibited weakly and promote strongly' as a function of time. In comparison, Lan had little influence on the activity of superoxide dismutase. The variance analysis results showed that the concentration of Lan significantly affected the activities of cellulose and CAT but had no obvious influence on the activities of SOD and POD. The treatment time and the interactive effect between treatment concentrations and time had very significant effect on the activities of cellulose, SOD, CAT and POD.
文摘The effects of silver sulfide (Ag 2S) on the bioleaching of chalcopyrite and pyrite were investigated in this paper. It has been shown that Ag 2S enhanced the yields of bioleaching of chalcopyrite but inhibited the bio oxidation of pyrite. The addition of Ag 2S selectively increased the copper dissolution from the chalcopyrite containing ores in shake flasks with a recovery of 85.3% compared with 24.3% without Ag 2S, while slightly decreased the iron yields from 51% to 41.8%. The copper extraction of the chalcoopyrite containing waste rock in column leaching charged with 18 kg mass increased up to 21.7% in the presence of Ag 2S, while only 3.4% in the absence of the catalyst. The mechanism of Ag 2S catalysis could be explained well by the "Mixed potential model".
基金Project (No. 2002CB410800) supported by the National NaturalScience Foundation of China
文摘Comparative study on the activity and kinectic properties of acid phosphatase （ACPase） of three soils amended with Hg and Cu at constant temperature and humidity was carried out. The results indicated that the inhibition on ACPase of the three sample soils by Hg and Cu varied with the content of soil organic matter and pH, where, Soil 1 was the most seriously contaminated due to its lowest content of organic matter and the lowest pH among three samples, Soil 2 took the second place, and Soil 3 was the least contaminated. Except Soil 3, the activity of soil ACPase tended to increase along with the contact time under the same type and the same concentration of heavy metal. In particular the Vmax values of ACPase in all three samples decreased with increasing Hg and Cu concentration, whereas the Km values were affected weakly. According to the change of Vmax and Km values, Cu and Hg had the same inhibition effect on soil ACPase. Both of them may he a type of compound of non-competitive and anti-competitive inhibition. Statistic analyses indicated that activities of soil ACPase and Vmax values could serve as bioindicator to partially denote the heavy metal Hg and Cu contamination degree.
基金supported by the National Natural Science Foundation of China (No.90813018)the Youth Foundation of Shanxi Province (No.2006021009)as well as the Youth Scientific and Technical Foundation of Shanxi University (Nos.2006007 and 2007112).
文摘The interaction of the novel tetra-carboxylphenyl calix[4]arene （TCPC） with the bovine heart cytochrome c （Cc） was first investigated by fluorescence spectroscopy and molecular modeling methods. The formation of a stable 1：1 complex was monitored by fluorescence titration, and its binding constant is 1.916 ×10^7 L mol^-1. Molecular modeling reveals the recognition mechanism of TCPC to the Cc surface, that is, the electrostatic interaction drives TCPC to the Cc surface, and the van der Waals interaction orientates TCPC parallel to the cleft of Cc.
基金supported financially by Ethiopian Biodiversity Institute。
文摘Species composition,structure,regeneration,and management status of Jorgo-Wato Forest(JWF)was studied.Number of individuals,diameter at breast height(dbh)and height of woody species(dbh≥2.5 cm)were counted and measured in each plot.Group discussions with local farmers residing around JWF were carried out to understand the management of the JWF.Forest structural attributes were computed using descriptive statistics;correlation was used to assess relationships between the structural variables.A total of 4313 individuals(dbh≥2.5 cm)with a density of 1477 ha-1 were recorded,the number of species and individuals decreasing with increasing dbh classes.Species with the highest Importance Value Index(IVI)were Pouteria adolfifriedericii(37.7),Syzygium guineense subsp.afromontanum(23.6),Dracaena afromontana(20.5),Chionanthus mildbraedii(15.9),and Croton macrostachyus(12.3).Overall distribution of woody plants across size classes exhibited a reverse J-pattern,suggesting a healthy population structure and good regeneration.Nevertheless,some species were not represented in smaller diameter classes,including juvenile phases,which indicate a lack of regeneration.For these species,monitoring and enrichment planting would be necessary,along with curbing illegal cutting and coffee farming in the natural forest.Management interventions in the JWF need to consider livelihood options and to respect the rights of local communities.
基金supported by the Key Project of National Natural Science Foundation of China(No.50534100)
文摘A novel potassium ions sensor based on mode-filtered light detection was reported. The analyzer was consisting of an optical fiber immobilized with a dye of bromocresol green and a fused-silica capillary. It was found that mode-filtered light intensity decreased with the concentration of potassium ions and a linear detection range of 0.25-20 mmol/L （R^2 = 0.9977） was obtained with a detection limit of 9 ×10^-5 mol/L as well as fast response, good reproducibility and reversibility in the working concentration range.
基金Supported by the National Natural Science Foundation of China(Nos.21175086,21105060)the Natural Science Foundation of Shanxi Province,China(No.2010011013-1)the Research Project Supported by Shanxi Scholarship Council,China
文摘The interaction of calf thymus DNA（ctDNA） with berberine（Ber） was systematically investigated via UV-Vis,fluorescence and phosphorescence spectroscopies in aqueous solution and on solid substrate.The very weak fluorescence intensity of Ber at 525 nm in aqueous solution can be greatly enhanced by ctDNA.The UV-Vis spectrum shows that Ber could bind with DNA by intercalation.In addition,strong fluorescence of Ber alone could be observed on filter paper substrate and can be quenched by ctDNA effectively,and the increase of fluorescence polarization of Ber on the filter paper implies the intercalation binding.Ber emits phosphorescence at 619 nm in the presence of thallium（I） acetate.The lifetime of Ber increased from 38.4 ms to 43.4 ms with the increase of ctDNA.The increase of lifetime is possibly attributed to the increase of rigidity of Ber after its intercalating into the ctDNA base pairs.This explanation is also augmented by the anionic quenching results.Ber behaves as a typical intercalating agent into ctDNA.The intrinsic binding constant between Ber and ctDNA is（1.84±0.12）×10^4 L/mol and n=0.16.
文摘The size distribution of fragmented rocks depends on not only the blasting standard but also the mechanical properties, joint system and crack density of rock mass. As, especially, the cracks in the rock mass are heavily developed at the limestone quarries in Japan, the joints and/or cracks in the rock mass have big impacts on the blasting effects such as the size of fragmented rocks. Therefore, if the joint system and/or crack density in the rock mass can be known and evaluated in quantity, the blasting operation can be done more effectively, efficiency and safety. However, the guideline for designing the appropriate blasting standard based on the rock mass condition such as mechanical properties, joint system and/or distribution of cracks, discontinuities, from the scientific point of view, has not been developed yet. Therefore, a series of blasting tests had been conducted in different mines and faces, geological conditions and blasting standards in order to know the impacts of each factor on the blasting effects. This paper summarizes the results of blasting tests and describes the impacts of rock mass conditions and blasting standard on the size of fragmented rocks.
文摘Morin (MR) is an anticancer drug present in fruits and Chinese herbs. Fe3O4 magnetic nanoparticles (MNPs) coated on 3-aminopropyl triethoxysilane (APTES) were synthesized (MNPs-APTES) as carriers for MR. The characterization of drug delivery system was confirmed by Fourier Transform Infrared (FTIR), Transmission Electron Microscope (TEM), X-Ray Diffraction (XRD), dynamic light scattering (DLS), and vibrating sample magnetometer (VSM). The adsorbed APTES on the magnetite surface (MNPs-APTES) was examined by FTIR. The TEM image showed that the average particle size is obtained to be about 26.7 nm for MNPs-APTES. The MR loading and release behavior of MNPs-APTES were studied and the results showed that up to 60% of the adsorbed drug was released within 4 h. In summary, the MNPs-APTES nanocarriers are based on the results, promising for targeted morin drug delivery.
文摘The main objective of this research work was to diagnose the vulnerability of terrestrial ecosystems to S deposition in Atasta region in Campeche State, Mexico, comprising two simultaneous sampling programs in both, soil and atmospheric deposition on an annual basis during three climatic periods: dry, rainy and cold fronts seasons. From the estimation of soil properties estimation (pH, texture, mineralogy, cationic exchange capacity, and basis saturation %), critical loads and sensitivity classes were assigned to sampled soils based according to the empirical methodology proposed by UNECE. During the dry season, 10 sites fell into sensitivity class 2 (moderately sensitive) and 3 (sensitive). On the other hand, during the rainy season, 8 sites showed a sensitivity class 1 (highly sensitive) and 2 sites presented a sensitivity class 2 (moderately sensitive);whereas along cold fronts season, 12 sites fell into sensitivity class 1 that corresponds to highly sensitive. Sensitivity classes showed a seasonal trend, with a higher sensitivity during rainy and cold fronts seasons;this agrees with the kind of sources influencing on the study area as a result of the prevailing meteorology during these climatic periods. Likewise, S concentration in atmospheric deposition was determined by turbidimetric method, and S deposition fluxes were estimated from surface area of the funnel opening of the sampling device and the sampling period. S deposition fluxes ranged from 0.29 and 14.06 kg S ha-1·yr-1;with a mean value of 8.57 kg S ha-1·yr-1. From the comparison between the current deposition rates and proposed critical loads, exceedances percentages were obtained (from 1.65% to 62.8%) and mapped to identify critical zones of S deposition in the studied area. It was established the important role which mangrove vegetation plays in the attenuation of the potential ecological effects on terrestrial ecosystems of the study area associated to atmospheric deposition.
基金financially supported by UEFISCDI,PNCDI III,project PN-III-P1-1.1-TE-2021(No.150/09.06.2022)supported by COST(European Cooperation in Science and Technology,available online:https://www.cost.eu,accessed on 20 November 2023)。
文摘Plasma treatment is necessary to optimize the performance of biomaterial surfaces.It enhances and regulates the performance of biomaterial su rfaces,creating an effective interface with the human body.Plasma treatments have the ability to modify the chemical com position and physical structu re of a surface while leaving its properties unaffected.They possess the ability to modify material su rfaces,eliminate contaminants,conduct investigations on cancer therapy,and facilitate wound healing.The subject of study in question involves the integration of plasma science and technology with biology and medicine.Using a helium plasma jet source,applying up to 18 kV,with an average power of 10 W,polymer foils were treated for 60 s.Plasma treatment has the ability to alter the chemical composition and physical structure of a su rface while maintaining its quality.This investigation involved the application of helium plasma at atmospheric pressure to polyamide 6 and polyethylene terephthalate sheets.The inquiry involves monitoring and assessing the plasma source and polymer materials,as well as analyzing the impacts of plasma therapy.Calculating the mean power of the discharge aids in assessing the economic efficacy of the plasma source.Electric discharge in helium at atmospheric pressure has beneficial effects in technology,where it increases the surface free energy of polymer materials.In biomedicine,it is used to investigate cytotoxicity and cell survival,particularly in direct blood exposure situations that can expedite coagulation.Comprehending the specific parameters that influence the plasma source in the desired manner for the intended application is of utmost im portance.
