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1.
Front Microbiol ; 15: 1392090, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38808273

RESUMO

Introduction: Through the combined use of two nitrification inhibitors, Dicyandiamide (DCD) and chlorate with nitrogen amendment, this study aimed to investigate the contribution of comammox Nitrospira clade B, ammonia oxidizing bacteria (AOB) and archaea (AOA) to nitrification in a high fertility grassland soil, in a 90-day incubation study. Methods: The soil was treated with nitrogen (N) at three levels: 0 mg-N kg-1 soil, 50 mg-N kg-1 soil, and 700 mg-N kg-1 soil, with or without the two nitrification inhibitors. The abundance of comammox Nitrospira, AOA, AOB, and nitrite oxidising bacteria (NOB) was measured using qPCR. The comammox Nitrospira community structure was assessed using Illumina sequencing. Results and Discussion: The results showed that the application of chlorate inhibited the oxidation of both NH4+ and NO2- in all three nitrogen treatments. The application of chlorate significantly reduced the abundance of comammox Nitrospira amoA and nxrB genes across the 90-day experimental period. Chlorate also had a significant effect on the beta diversity (Bray-Curtis dissimilarity) of the comammox Nitrospira clade B community. Whilst AOB grew in response to the N substrate additions and were inhibited by both inhibitors, AOA showed litle or no response to either the N substrate or inhibitor treatments. In contrast, comammox Nitrospira clade B were inhibited by the high ammonium concentrations released from the urine substrates. These results demonstrate the differential and niche responses of the three ammonia oxidising communities to N substrate additions and nitrification inhibitor treatments. Further research is needed to investigate the specificity of the two inhibitors on the different ammonia oxidising communities.

2.
Sensors (Basel) ; 23(9)2023 Apr 29.
Artigo em Inglês | MEDLINE | ID: mdl-37177591

RESUMO

Spatial variation of indoor and outdoor PM2.5 within three states for a five-year period is studied using regulatory and low-cost PurpleAir monitors. Most of these data were collected in an earlier study (Wallace et al., 2022 Indoor Air 32:13105) investigating the relative contribution of indoor-generated and outdoor-infiltrated particles to indoor exposures. About 260 regulatory monitors and ~10,000 outdoor and ~4000 indoor PurpleAir monitors are included. Daily mean PM2.5 concentrations, correlations, and coefficients of divergence (COD) are calculated for pairs of monitors at distances ranging from 0 (collocated) to 200 km. We use a transparent and reproducible open algorithm that avoids the use of the proprietary algorithms provided by the manufacturer of the sensors in PurpleAir PA-I and PA-II monitors. The algorithm is available on the PurpleAir API website under the name "PM2.5_alt". This algorithm is validated using several hundred pairs of regulatory and PurpleAir monitors separated by up to 0.5 km. The PM2.5 spatial variation outdoors is homogeneous with high correlations to at least 10 km, as shown by the COD index under 0.2. There is also a steady improvement in outdoor PM2.5 concentrations with increasing distance from the regulatory monitors. The spatial variation of indoor PM2.5 is not homogeneous even at distances < 100 m. There is good agreement between PurpleAir outdoor monitors located <100 m apart and collocated Federal Equivalent Methods (FEM).

3.
Front Microbiol ; 13: 1048735, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36578577

RESUMO

The recent discovery of comammox Nitrospira, a complete ammonia oxidizer, capable of completing the nitrification on their own has presented tremendous challenges to our understanding of the nitrification process. There are two divergent clades of comammox Nitrospira, Clade A and B. However, their population abundance, community structure and role in ammonia and nitrite oxidation are poorly understood. We conducted a 94-day microcosm study using a grazed dairy pasture soil amended with urea fertilizers, synthetic cow urine, and the nitrification inhibitor, dicyandiamide (DCD), to investigate the growth and community structure of comammox Nitrospira spp. We discovered that comammox Nitrospira Clade B was two orders of magnitude more abundant than Clade A in this fertile dairy pasture soil and the most abundant subcluster was a distinctive phylogenetic uncultured subcluster Clade B2. We found that comammox Nitrospira Clade B might not play a major role in nitrite oxidation compared to the role of canonical Nitrospira nitrite-oxidizers, however, comammox Nitrospira Clade B is active in nitrification and the growth of comammox Nitrospira Clade B was inhibited by a high ammonium concentration (700 kg synthetic urine-N ha-1) and the nitrification inhibitor DCD. We concluded that comammox Nitrospira Clade B: (1) was the most abundant comammox in the dairy pasture soil; (2) had a low tolerance to ammonium and can be inhibited by DCD; and (3) was not the dominant nitrite-oxidizer in the soil. This is the first study discovering a new subcluster of comammox Nitrospira Clade B2 from an agricultural soil.

4.
Indoor Air ; 32(9): e13105, 2022 09.
Artigo em Inglês | MEDLINE | ID: mdl-36168225

RESUMO

Low-cost monitors have made it possible for the first time to measure indoor PM2.5 concentrations over extended periods of time (months to years). Coupled with concurrent outdoor measurements, these indoor measurements can be divided into particles entering the building from outdoors and particles generated from indoor activities. Indoor-generated particles are not normally considered in epidemiological studies, but they can have health effects (e.g., passive smoking and high-temperature cooking). We employed The Random Component Superposition (RCS) regression model to estimate infiltration factors for up to 790 000 matched indoor and outdoor sites. The median infiltration factors for subgroups in the 3-state region ranged between 0.22 and 0.24, with an interquartile range (IQR) of 0.13-0.40. These infiltration factors allowed calculation of both the indoor-generated and outdoor-infiltrated PM2.5 . Indoor-generated particles contributed, on average, 46%-52% of total indoor PM2.5 concentrations. However, the site-specific fractional contribution of these indoor sources to total indoor PM2.5 ranged from near-zero to nearly 100%. The influence of indoor-generated particles on potential exposures varied widely relative to outdoor concentrations. The greatest influence of indoor-generated particles occurred at low-to-moderate daily mean outdoor PM2.5 levels around 6 µg/m3 and was negligible at outdoor concentrations >20 µg/m3 . Epidemiological studies incorporating only estimated exposures due to the particles of ambient origin may benefit from the newly available knowledge of long-term indoor-generated particle concentrations.


Assuntos
Poluentes Atmosféricos , Poluição do Ar em Ambientes Fechados , Poluição por Fumaça de Tabaco , Poluentes Atmosféricos/análise , Poluição do Ar em Ambientes Fechados/análise , Monitoramento Ambiental , Oregon , Tamanho da Partícula , Material Particulado/análise , Washington
5.
Sensors (Basel) ; 22(13)2022 Jun 23.
Artigo em Inglês | MEDLINE | ID: mdl-35808235

RESUMO

Large quantities of real-time particle data are becoming available from low-cost particle monitors. However, it is crucial to determine the quality of these measurements. The largest network of monitors in the United States is maintained by the PurpleAir company, which offers two monitors: PA-I and PA-II. PA-I monitors have a single sensor (PMS1003) and PA-II monitors employ two independent PMS5003 sensors. We determine a new calibration factor for the PA-I monitor and revise a previously published calibration algorithm for PA-II monitors (ALT-CF3). From the PurpleAir API site, we downloaded 83 million hourly average PM2.5 values in the PurpleAir database from Washington, Oregon, and California between 1 January 2017 and 8 September 2021. Daily outdoor PM2.5 means from 194 PA-II monitors were compared to daily means from 47 nearby Federal regulatory sites using gravimetric Federal Reference Methods (FRM). We find a revised calibration factor of 3.4 for the PA-II monitors. For the PA-I monitors, we determined a new calibration factor (also 3.4) by comparing 26 outdoor PA-I sites to 117 nearby outdoor PA-II sites. These results show that PurpleAir PM2.5 measurements can agree well with regulatory monitors when an optimum calibration factor is found.


Assuntos
Poluentes Atmosféricos , Poluição do Ar , Poluentes Atmosféricos/análise , Poluição do Ar/análise , Calibragem , California , Monitoramento Ambiental/métodos , Oregon , Material Particulado/análise , Washington
6.
Ying Yong Sheng Tai Xue Bao ; 31(11): 3719-3728, 2020 Nov.
Artigo em Chinês | MEDLINE | ID: mdl-33300722

RESUMO

A field experiment was conducted for two seasons to evaluate the application effects of a decision support system named Nutrient Expert on radish based on yield response and agronomic efficiency, to provide theoretical and technical support for convenient and quick recommendation on fertilization management. There were seven treatments: farmer's practice treatment (FP), recommended fertilization treatment based on Nutrient Expert (TE), recommended fertilization treatment based on soil testing (TS), treatment of replacing 30% nitrogen fertilizer with organic fertilizer based on TE (TE+OM), and corresponding nitrogen omission treatment (TE-N), phosphorus omission treatment (TE-P), and potassium omission treatment (TE-K). We measured and compared the effects of different fertilization managements on radish yield, nutrient uptake, fertilizer utilization and fertilization benefit. The results showed that the N, P2O5 and K2O fertilizer applications based on Nutrient Expert were 200, 132 and 215 kg·hm-2 in the first half of the year, and 171, 204 and 251 kg·hm-2 in the second half of the year, respectively. The Nutrient Expert recommended fertilization adjusted the application amount of nitrogen, phosphorus, and potassium fertilizer. Compared with FP treatment, the economic yield of radish in the two-season experiments increased by 14.8% and 18.4%, and the profit of fertilization increased by 20115 and 14905 yuan·hm-2, respectively. Compared with the TS treatment, the economic yield of radish over the two seasons increased by 9.8% and 16.8%, and the profit of fertilization increased by 9076 and 9987 yuan·hm-2, respectively. The Nutrient Expert recommended fertilization improved the agronomic efficiency and nutrient recovery efficiency of radish, and promoted the efficient utilization of nutrients. The reasonable proportion of organic fertilizer in radish production could promote the transfer of plant nutrients to roots to a certain extent. In general, the application of Nutrient Expert on radish was feasible. This method could make full use of the indigenous nutrients of soil, consider the balance and sustainable supply, and reasonably regulate the supply of nitrogen, phosphorus and potassium, and finally result in high yield, high efficiency and sustainable development of radish production.


Assuntos
Fertilizantes , Raphanus , Sistemas Inteligentes , Nutrientes , Solo
7.
J Environ Manage ; 270: 110867, 2020 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-32507744

RESUMO

Water pollution caused by antibiotics and heavy metals has attracted considerable concern, and efficient approaches are urgently needed for their removal. The objective of this study was to investigate the potential of Myriophyllum aquaticum for long-term phytoremediation of wastewater containing tetracycline (TC) antibiotics and copper. Seven hydroponic microcosms were constructed, spiked with tetracycline, oxytetracycline (OTC) and chlortetracycline (CTC) (300-30,000 µg/L), alone or simultaneously with Cu (II), and operated for 12 weeks. The TC removal efficiencies using the hydroponic microcosms here were commensurate or higher than those in previous studies. However, the Cu/TC ratio greatly affected the removal, accumulation of TCs by M. aquaticum, and plant growth. Low levels of Cu (II) (<1000 µg/L) promoted TC removal, but excessive Cu (II) (>10,000 µg/L) impeded it. Mass balance analysis showed that most TCs (45%-64% on average) accumulated in the roots of M. aquaticum. Plant biomass was correlated with the removal of COD, TN, TP, and NH4+-N (p ≤ 0.05) but not with removal of the TCs. Proteobacteria, Bacteroidetes, and Fusobacteria were dominant in the microbial communities, but they showed little correlation with the TC removal. M. aquaticum can be employed as an effective means of TC removal from water. The co-existence of heavy metals should be considered when evaluating the removal potential of TCs in phytoremediation.


Assuntos
Cobre , Poluentes Químicos da Água/análise , Antibacterianos , Biodegradação Ambiental , Tetraciclina , Águas Residuárias , Água
8.
Environ Pollut ; 261: 114204, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32097793

RESUMO

Antibiotic and heavy metal pollution of aquatic environments are issues of serious concern, and the macrophyte Myriophyllum aquaticum may provide a viable solution for the removal of these contaminants. However, the toxic effects of coexisting tetracyclines (TCs) and Cu(II) on this plant species are currently unclear. In the present study, we constructed wetland microcosms planted with M. aquaticum and spiked these with three TCs (tetracycline, oxytetracycline, and chlortetracycline) and Cu(II) at concentrations ranging from 100 to 10,000 µg/L to investigate how Cu(II) influences the growth and tolerance responses of plants to TCs. After 12 weeks, we found that TCs had accumulated in the plants, and that plant growth and characteristics were significantly affected by the levels of both TCs and Cu(II). While low Cu(II) levels had a synergistic effect on the accumulation of TCs, high levels were observed to reduce accumulation. However, low levels of TCs and Cu(II) had a hormesis effect on plant growth, with plant biomass and leaf chlorophyll content decreasing and the malondialdehyde content and activities of antioxidant enzymes gradually increasing with an increase in TC dosage. The coexistence of low levels of Cu(II) was, however, found to alleviate these adverse effects. Principal component analysis revealed a close relationship among plant biomass, chlorophyll content, malondialdehyde content, and antioxidant enzyme activities. Considering that the Cu/TC ratio was shown to markedly affect M. aquaticum growth, the respective proportions of these pollutants should be taken into consideration in the future design of constructed wetlands.


Assuntos
Cobre , Magnoliopsida , Tetraciclinas , Áreas Alagadas , Antibacterianos/farmacologia , Cobre/farmacologia , Magnoliopsida/efeitos dos fármacos , Magnoliopsida/crescimento & desenvolvimento , Tetraciclinas/farmacologia , Poluentes Químicos da Água/farmacologia
9.
Artigo em Inglês | MEDLINE | ID: mdl-31623089

RESUMO

This study aimed to investigate the characteristics of gaseous emission (methane-CH4, carbon dioxide-CO2, nitrous oxide-N2O, nitric oxide-NO, hydrogen sulfide-H2S and sulfur dioxide-SO2) and the conservation of carbon (C), nitrogen (N), and sulfur (S) during cattle manure composting under different aeration strategies. Three aeration strategies were set as C60, C100, and I60, representing the different combinations of aeration method (continuous-C or intermittent-I) and aeration rate (60 or 100 L·min-1·m-3). Results showed that C, N, S mass was reduced by 48.8-53.1%, 29.8-35.9% and 19.6-21.9%, respectively, after the composing process. Among the three strategies, the intermittent aeration treatment I60 obtained the highest N2O emissions, resulting in the highest N loss and greenhouse gas (GHG) emissions when the GHG emissions from power consumption were not considered. Within two continuous aeration treatments, lower aeration rates in C60 caused lower CO2, N2O, NO, and SO2 emissions but higher CH4 emissions than those from C100. Meanwhile, C and N losses were also lowest in the C60 treatment. H2S emission was not detected because of the more alkaline pH of the compost material. Thus, C60 can be recommended for cattle manure composting because of its nutrient conservation and mitigation of major gas and GHG emissions.


Assuntos
Dióxido de Carbono/análise , Compostagem/métodos , Esterco/análise , Nitrogênio/análise , Enxofre/análise , Aerobiose , Anaerobiose , Animais , Bovinos
10.
Environ Pollut ; 254(Pt B): 113101, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31472457

RESUMO

As a floating plant, Myriophyllum aquaticum provides a large surface area under water, and thus has high potential for the removal of pollutants through adsorption. The aim of this study was to evaluate the potential adsorption of tetracycline (TC) by M. aquaticum, and examine the underlying mechanisms. M. aquaticum exhibited a high potential for TC removal from water. Adsorption was the main mechanism for rapid TC removal by live M. aquaticum plants, due to its large contact area and ion exchange, accounting for about 99% and 54% of the total amount of TC removed within 2 h and 5 d, respectively. Further, the roots of M. aquaticum exhibited a higher adsorption capacity than the stems or leaves, as the roots had the largest specific surface area. Fourier transform infrared spectroscopy analysis and identification of functional groups showed that -OH, -COOH, and -NH2 groups are involved in the adsorption process. The use of M. aquaticum may be a promising approach for TC removal from aquatic environments, especially in terms of shortening reaction times.


Assuntos
Magnoliopsida/química , Tetraciclina/química , Poluentes Químicos da Água/química , Adsorção , Troca Iônica , Magnoliopsida/metabolismo , Raízes de Plantas/química , Tetraciclina/análise , Águas Residuárias/química , Poluentes Químicos da Água/análise , Purificação da Água/métodos
11.
Bioresour Technol ; 291: 121916, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31377514

RESUMO

Pollution with antibiotics and heavy metals necessitates efficient approaches for their removal. This study was conducted to investigate the role of Cu in the tetracycline (TC) removal potential of the floating plant Myriophyllum aquaticum and determine the underlying mechanisms. Myriophyllum aquaticum exhibited high TC removal potential from water (60% at 50 mg·L-1 TC and 10 g·L-1M. aquaticum). Adsorption was the main mechanism of TC removal within 2 h, accounting for over 75% and 90% of total TC removal with and without Cu(II), respectively. Fourier-transform infrared spectroscopy and functional group identification showed that OH, COOH, and NH2 were involved in TC adsorption through ion exchange. Cu(II) may act as a bridge during TC adsorption with M. aquaticum, but competitive adsorption of Cu(II) and TC on M. aquaticum occurs in case of excessive Cu(II). Myriophyllum aquaticum can serve as an important bioresource for effectively removing TC and Cu(II) from aquatic environments.


Assuntos
Cobre , Poluentes Químicos da Água , Adsorção , Antibacterianos , Tetraciclina , Água
12.
J Environ Manage ; 235: 105-111, 2019 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-30677654

RESUMO

Although Myriophyllum aquaticum exhibits efficient nitrogen and phosphorus removal from wastewater, it has poor performance on organic matter removal. Here, a wastewater treatment system combining M. aquaticum and activated sludge was developed to improve its removal of organic matter. The Box-Behnken response surface methodology was used to optimize the construction conditions of the system, and the effects of time, temperature, illumination intensity, pollutant load, and dissolved oxygen (DO) on plant mass increment (PMI) and microbial biomass (MB) of the system were investigated. The wastewater remediation potential of the system was then evaluated. The results show that temperature and illumination intensity significantly affected PMI (p < 0.01), and that time, pollutant load, and DO were the most significant factors affecting MB (p < 0.01). The optimal construction conditions were 18.77 days in length, a temperature of 20.42 °C, an illumination intensity of 5827.61 Lx, a pollutant load of 120.61 mg/g plant, and a DO of 3.21 mg/L. The inoculation of activated sludge caused MB of the system to increase by four times relative to the non-inoculated system, suggesting successful formation of biofilms on M. aquaticum. Additionally, the removal of chemical oxygen demand (COD) from wastewater was significantly enhanced by the combined approach compared with a system relying solely on M. aquaticum. This study provides a new method for improving the remediation efficiency of M. aquaticum by combining the use of this species and activated sludge.


Assuntos
Esgotos , Águas Residuárias , Biomassa , Reatores Biológicos , Nitrogênio , Fósforo , Eliminação de Resíduos Líquidos
13.
Ecotoxicol Environ Saf ; 170: 708-715, 2019 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-30580165

RESUMO

Atmospheric particulate matter( PM10, PM2.5) has been the main pollutant in most cities of China in recent years, and the exposure concentration is related to the incidence of human diseases and mortality. The time spent indoors is more than 80% for modern people. Therefore, study on the correlation and exposure level of indoor and outdoor atmospheric particles is important. To research the exposure level in the heating season and non-heating season of indoor and outdoor particulate concentration in severe cold region of China, a total of 110 samples of four types of buildings (office, classroom, urban residence and rural residence) in Daqing, a typical city of severe cold region in China, were tested by particle monitor. Based on the indoor and outdoor environmental parameters, multiple linear regression (MLR) and principal component regression (PCR), established the indoor particulate concentration prediction models. The short and long term exposure of different people in different environments in severe cold region of China was analyzed based on the people's time-activity pattern with the measured data and model. The results showed that as for the short term indoor and outdoor exposure of different people, the average combined exposure of urban people in heating season is 60.0% higher than that in non-heating season, and rural people in heating season 30.2% higher than that in non-heating season. As for the long term indoor and outdoor exposure of different people, the annual average combined exposure of urban people was 9.6% higher than that of rural people. While all for urban and rural people, differences in respiratory rates between genders resulted in an average potential dose of 21. 8% higher in male than in female.


Assuntos
Poluentes Atmosféricos/análise , Poluição do Ar em Ambientes Fechados/análise , Exposição Ambiental/análise , Material Particulado/análise , China , Temperatura Baixa , Feminino , Habitação , Humanos , Modelos Lineares , Masculino , Análise Multivariada , Análise de Componente Principal , Taxa Respiratória , População Rural , Instituições Acadêmicas , Estações do Ano , Fatores de Tempo , População Urbana
14.
Bioresour Technol ; 235: 43-49, 2017 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-28360019

RESUMO

Composting is regarded as an effective treatment to suppress pathogenic organisms and stabilize the organic material in sewage sludge. This study investigated the use of biochar as an amendment to improve the composting effectiveness and reduce the bioavailability of heavy metals and loss of nitrogen during composting. Biochar of 0%, 1%, 3%, 5% and 7% were added into a mixture of sludge and straw, respectively. The use of biochar, even in small amounts, altered the composting process and the properties of the end products. Biochar addition resulted in a higher pile temperature (66°C) and could reduce nitrogen loss by transforming ammonium into nitrite. In the 5% biochar group, the final product from sludge composting, ammonia nitrogen, decreased by 22.4% compared to the control, and nitrate nitrogen increased by 310.6%. Considering temperature and N transformation, the treatment with 5% biochar is suggested for sludge composting.


Assuntos
Esgotos , Metais Pesados , Nitrogênio , Solo , Temperatura
15.
16.
PLoS One ; 11(9): e0162802, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27631468

RESUMO

In order to make clear the recent status and trend of wheat (Triticum aestivum L.) production in China, datasets from multiple field experiments and published literature were collected to study the agronomic characteristics related to grain yield, fertilizer application and nutrient use efficiency from the year 2000 to 2011. The results showed that the mean grain yield of wheat in 2000-2011 was 5950 kg/ha, while the N, P2O5 and K2O application rates were 172, 102 and 91 kg/ha on average, respectively. The decrease in N and P2O5 and increase in K2O balanced the nutrient supply and was the main reason for yield increase. The partial factor productivity (PFP, kg grain yield produced per unit of N, P2O5 or K2O applied) values of N (PFP-N), P (PFP-P) and K (PFP-K) were in the ranges of 29.5~39.6, 43.4~74.9 and 44.1~76.5 kg/kg, respectively. While PFP-N showed no significant changes from 2000 to 2010, both PFP-P and PFP-K showed an increased trend over this period. The mean agronomic efficiency (AE, kg grain yield increased per unit of N, P2O5 or K2O applied) values of N (AEN), P (AEP) and K (AEK) were 9.4, 10.2 and 6.5 kg/kg, respectively. The AE values demonstrated marked inter-annual fluctuations, with the amplitude of fluctuation for AEN greater than those for AEP and AEK. The mean fertilizer recovery efficiency (RE, the fraction of nutrient uptake in aboveground plant dry matter to the nutrient of fertilizer application) values of N, P and K in the aboveground biomass were 33.1%, 24.3% and 28.4%, respectively. It was also revealed that different wheat ecological regions differ greatly in wheat productivity, fertilizer application and nutrient use efficiency. In summary, it was suggested that best nutrient management practices, i.e. fertilizer recommendation applied based on soil testing or yield response, with strategies to match the nutrient input with realistic yield and demand, or provided with the 4R's nutrient management (right time, right rate, right site and right fertilizer) should be adopted widely to improve the yield production and nutrient use efficiency.


Assuntos
Solo , Triticum/crescimento & desenvolvimento , China , Fertilizantes
17.
PLoS One ; 11(5): e0154447, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27223106

RESUMO

In this study, we have generated and characterized Electronic Cigarette (EC) aerosols using a combination of advanced technologies. In the gas phase, the particle number concentration (PNC) of EC aerosols was found to be positively correlated with puff duration whereas the PNC and size distribution may vary with different flavors and nicotine strength. In the liquid phase (water or cell culture media), the size of EC nanoparticles appeared to be significantly larger than those in the gas phase, which might be due to aggregation of nanoparticles in the liquid phase. By using in vitro high-throughput cytotoxicity assays, we have demonstrated that EC aerosols significantly decrease intracellular levels of glutathione in NHOKs in a dose-dependent fashion resulting in cytotoxicity. These findings suggest that EC aerosols cause cytotoxicity to oral epithelial cells in vitro, and the underlying molecular mechanisms may be or at least partially due to oxidative stress induced by toxic substances (e.g., nanoparticles and chemicals) present in EC aerosols.


Assuntos
Glutationa/metabolismo , Queratinócitos/metabolismo , Boca/metabolismo , Estresse Oxidativo , Vaping/efeitos adversos , Aerossóis , Humanos , Queratinócitos/patologia , Boca/patologia , Nicotina/efeitos adversos , Nicotina/farmacologia
18.
Ying Yong Sheng Tai Xue Bao ; 26(1): 76-86, 2015 Jan.
Artigo em Chinês | MEDLINE | ID: mdl-25985656

RESUMO

In this study, the input and output parameters of N for wheat production were collected from published literatures and International Plant Nutrition Institute in the period of 2000 to 2011 to evaluate N cycling and balances in North China, the middle and lower reaches of Yangtze River and Northwest China. The results showed that the N fertilizer application rates for each region were 170, 183 and 150 kg N . hm-2, the amounts of N from the previous crop were 74.6, 15.2 and 8.1 kg N . hm-2, and from seeds were 4.9, 4.2 and 3.5 kg N . hm-2, respectively. The N inputs from symbiotic fixation, atmospheric deposition and irrigation water in North China were 15, 12.9 and 9.9 kg N . hm-2, and in the middle and lower reaches of Yangtze River were 15, 14.5 and 5.8 kg N . hm-2, and in Northwest China were 15, 9.4 and 7.7 kg N . hm-2, respectively. The amounts of N uptake by aboveground plant at harvest time in North China, the middle and lower reaches of Yangtze River and Northwest China were 174.3, 144.4 and 122.3 kg N . hm-2, respectively, and the rates of ammonia volatilization, N20 emission and N leaching in North China were 19.9, 2.6 and 11.8 kg N . hm-2, in the middle and lower reaches of Yangtze River were 9.4, 2.4 and 15.5 kg N . hm-2, and in Northwest China were 3.4, 0.7 and 0 kg N . hm-2, respectively. As a result, the N balances in these three regions were all showing surpluses by 78.7, 66.0 and 67.3 kg N . hm-2. It is therefore necessary to adjust the N fertilizer application rates in these three regions to avoid the negative impacts on the environment.


Assuntos
Fertilizantes , Ciclo do Nitrogênio , Nitrogênio/química , Triticum/fisiologia , Amônia , China , Meio Ambiente , Rios , Solo/química
19.
Ying Yong Sheng Tai Xue Bao ; 21(1): 115-20, 2010 Jan.
Artigo em Chinês | MEDLINE | ID: mdl-20387432

RESUMO

Four kinds of organic-inorganic cementing and coating materials were prepared by a coating method using water as the solvent, and the corresponding cemented and coated fertilizers (B2, PS, F2, and F2F) were produced by disc pelletizer. The tests on the properties of these fertilizers showed that the granulation rate, compression strength, and film-forming rate were B2 > PS > F2 > F2F. Soil column leaching experiment showed that the curve of accumulated nitrogen-dissolving rate was the gentlest for B2. In 48 days, the accumulated nitrogen-dissolving rate was in the order of B2, 54.65% < PS, 56.16% < F2, 59.47%, < F2F, 63.12%. Field experiment showed that compared with the same application amount of NPK, all the test fertilizers had better effects on corn yield, among which, B2 was the best, with the corn yield and fertilizer use efficiency increased by 19.72% and 20.30%, respectively. The yield-increasing effect of other test fertilizers was in the order of PS > F2 > F2F.


Assuntos
Fertilizantes , Nitrogênio/química , Zea mays/crescimento & desenvolvimento , Biomassa , Cimentação/métodos , Fenômenos Químicos , Compostos Inorgânicos/química , Compostos Orgânicos/química
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