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1.
Nat Commun ; 15(1): 5163, 2024 Jun 17.
Artigo em Inglês | MEDLINE | ID: mdl-38886381

RESUMO

As the most abundant organic substances in nature, carbohydrates are essential for life. Understanding how carbohydrates regulate proteins in the physiological and pathological processes presents opportunities to address crucial biological problems and develop new therapeutics. However, the diversity and complexity of carbohydrates pose a challenge in experimentally identifying the sites where carbohydrates bind to and act on proteins. Here, we introduce a deep learning model, DeepGlycanSite, capable of accurately predicting carbohydrate-binding sites on a given protein structure. Incorporating geometric and evolutionary features of proteins into a deep equivariant graph neural network with the transformer architecture, DeepGlycanSite remarkably outperforms previous state-of-the-art methods and effectively predicts binding sites for diverse carbohydrates. Integrating with a mutagenesis study, DeepGlycanSite reveals the guanosine-5'-diphosphate-sugar-recognition site of an important G-protein coupled receptor. These findings demonstrate DeepGlycanSite is invaluable for carbohydrate-binding site prediction and could provide insights into molecular mechanisms underlying carbohydrate-regulation of therapeutically important proteins.


Assuntos
Aprendizado Profundo , Sítios de Ligação , Carboidratos/química , Ligação Proteica , Redes Neurais de Computação , Humanos , Proteínas/metabolismo , Proteínas/química , Modelos Moleculares
2.
Biology (Basel) ; 13(3)2024 Mar 19.
Artigo em Inglês | MEDLINE | ID: mdl-38534463

RESUMO

To uncover the internal mechanisms of various drought stress intensities affecting the soluble sugar content in organs and its regulation by endogenous abscisic acid (ABA), we selected the saplings of Platycladus orientalis, a typical tree species in the Beijing area, as our research subject. We investigated the correlation between tree soluble sugars and endogenous ABA in the organs (comprised of leaf, branch, stem, coarse root, and fine root) under two water treatments. One water treatment was defined as T1, which stopped watering until the potted soil volumetric water content (SWC) reached the wilting coefficient and then rewatered the sapling. The other water treatment, named T2, replenished 95% of the total water loss of one potted sapling every day and irrigated the above-mentioned sapling after its SWC reached the wilt coefficients. The results revealed that (1) the photosynthetic physiological parameters of P. orientalis were significantly reduced (p < 0.05) under fast and slow drought processes. The photosynthetic physiological parameters of P. orientalis in the fast drought-rehydration treatment group recovered faster relative to the slow drought-rehydration treatment group. (2) The fast and slow drought treatments significantly (p < 0.05) increased the ABA and soluble sugar contents in all organs. The roots of the P. orientalis exhibited higher sensitivity in ABA and soluble sugar content to changes in soil moisture dynamics compared to other organs. (3) ABA and soluble sugar content of P. orientalis showed a significant positive correlation (p < 0.05) under fast and slow drought conditions. During the rehydration stage, the two were significantly correlated in the T2 treatment (p < 0.05). In summary, soil drought rhythms significantly affected the photosynthetic parameters, organ ABA, and soluble sugar content of P. orientalis. This study elucidates the adaptive mechanisms of P. orientalis plants to drought and rehydration under the above-mentioned two water drought treatments, offering theoretical insights for selecting and cultivating drought-tolerant tree species.

3.
Nat Commun ; 15(1): 313, 2024 Jan 05.
Artigo em Inglês | MEDLINE | ID: mdl-38182565

RESUMO

Geometric deep learning has been revolutionizing the molecular modeling field. Despite the state-of-the-art neural network models are approaching ab initio accuracy for molecular property prediction, their applications, such as drug discovery and molecular dynamics (MD) simulation, have been hindered by insufficient utilization of geometric information and high computational costs. Here we propose an equivariant geometry-enhanced graph neural network called ViSNet, which elegantly extracts geometric features and efficiently models molecular structures with low computational costs. Our proposed ViSNet outperforms state-of-the-art approaches on multiple MD benchmarks, including MD17, revised MD17 and MD22, and achieves excellent chemical property prediction on QM9 and Molecule3D datasets. Furthermore, through a series of simulations and case studies, ViSNet can efficiently explore the conformational space and provide reasonable interpretability to map geometric representations to molecular structures.

4.
Plants (Basel) ; 12(15)2023 Jul 31.
Artigo em Inglês | MEDLINE | ID: mdl-37570989

RESUMO

To explore whether there were differences among the patterns of response of grasslands with different levels of degradation to extreme drought events and nitrogen addition, three grasslands along a degradation gradient (extremely, moderately, and lightly degraded) were selected in the Bashang area of northern China using the human disturbance index (HDI). A field experiment with simulated extreme spring drought, nitrogen addition, and their interaction was conducted during the growing seasons of 2020 and 2021. The soil moisture, aboveground biomass, and composition of the plant community were measured. The primary results were as follows. (1) Drought treatment caused soil drought stress, with moderately degraded grassland being the most affected, which resulted in an 80% decrease in soil moisture and a 78% decrease in aboveground biomass. The addition of nitrogen did not mitigate the impact of drought. Moreover, the aboveground net primary production (ANPP) in 2021 was less sensitive to spring drought than in 2020. (2) The community composition changed after 2 years of drought treatment, particularly for the moderately degraded grasslands with annual forbs, such as Salsola collina, increasing significantly in biomass proportion, which led to a trend of exacerbated degradation (higher HDI). This degradation trend decreased under the addition of nitrogen. (3) The variation in drought sensitivities of the ANPP was primarily determined by the proportion of plants based on the classification of degradation indicators in the community, with higher proportions of intermediate degradation indicator species exhibiting more sensitivity to spring drought. These findings can help to provide scientific evidence for the governance and restoration of regional degraded grassland under frequent extreme weather conditions.

5.
IEEE Trans Pattern Anal Mach Intell ; 45(1): 980-998, 2023 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-35077355

RESUMO

Detecting hot social events (e.g., political scandal, momentous meetings, natural hazards, etc.) from social messages is crucial as it highlights significant happenings to help people understand the real world. On account of the streaming nature of social messages, incremental social event detection models in acquiring, preserving, and updating messages over time have attracted great attention. However, the challenge is that the existing event detection methods towards streaming social messages are generally confronted with ambiguous events features, dispersive text contents, and multiple languages, and hence result in low accuracy and generalization ability. In this paper, we present a novel reinForced, incremental and cross-lingual social Event detection architecture, namely FinEvent, from streaming social messages. Concretely, we first model social messages into heterogeneous graphs integrating both rich meta-semantics and diverse meta-relations, and convert them to weighted multi-relational message graphs. Second, we propose a new reinforced weighted multi-relational graph neural network framework by using a Multi-agent Reinforcement Learning algorithm to select optimal aggregation thresholds across different relations/edges to learn social message embeddings. To solve the long-tail problem in social event detection, a balanced sampling strategy guided Contrastive Learning mechanism is designed for incremental social message representation learning. Third, a new Deep Reinforcement Learning guided density-based spatial clustering model is designed to select the optimal minimum number of samples required to form a cluster and optimal minimum distance between two clusters in social event detection tasks. Finally, we implement incremental social message representation learning based on knowledge preservation on the graph neural network and achieve the transferring cross-lingual social event detection. We conduct extensive experiments to evaluate the FinEvent on Twitter streams, demonstrating a significant and consistent improvement in model quality with 14%-118%, 8%-170%, and 2%-21% increases in performance on offline, online, and cross-lingual social event detection tasks.

6.
Ying Yong Sheng Tai Xue Bao ; 33(8): 2153-2160, 2022 Aug.
Artigo em Chinês | MEDLINE | ID: mdl-36043822

RESUMO

Based on community investigation data from grasslands on two different soil parent material types (loess and sand parent materials) and under three human utilization modes in the Saihan Ullah Reserve, we calculated human disturbance index (HDI) and biodiversity indices and analyzed the interactions between species diversity and degradation levels. The results showed that degradation status varied across different soil parent material types and human utilization modes, and that degradation levels of loess and sand parent materials both increased with the enhancement of human utilization intensification. HDI of loess parent material grasslands (mean value of 1.21) was lower than sand parent material grasslands (mean value of 1.48) in the same human utilization. Biodiversity indices declined with soil sandy degree and the utilization intensification. The mean values of Margarlef richness index, Shannon diversity index, Simpson dominance index and Pielou evenness index were between 1.57-4.27, 1.16-2.39, 0.76-0.87, and 0.71-0.80, respectively. The Margalef richness index, Shannon diversity index and Simpson dominance index decreased with increasing HDI, while Pielou evenness index increased. Overgrazing could lead to serious threat on both grasslands with soil parent material types, and the optimum utilization mode of loess and sand parent material grasslands were enclosure with mowing and seasonal grazing. In the future works of biodiversity conservation, it is important to consider the influence of both different soil patent material and human utilization modes of grassland. It is urgent to develop different utilization modes for grassland under different soil parent material types, which would enhance the matchness of grassland restoration and management with local conditions.


Assuntos
Pradaria , Solo , Biodiversidade , Humanos , Plantas/metabolismo , Areia
7.
Ying Yong Sheng Tai Xue Bao ; 33(6): 1466-1474, 2022 Jun.
Artigo em Chinês | MEDLINE | ID: mdl-35729121

RESUMO

In this study, we examined the regularity of phenological rhythmical change of plant water-soluble compound δ13C (δ13Cwsc) in spring for two typical tree species in the warm temperate zone of China, Pinus tabuliformis and Robinia pseudoacacia. The δ13Cwsc in each organ of those two species in the spring phenological period were measured to explore the relationship between δ13Cwsc and related environmental factors. The results showed that there were significant differences in δ13Cwsc values of each organ between P. tabuliformis and R. pseudoacacia, with higher δ13Cwsc(-25.03‰±0.01‰) in the new shoot of P. tabuliformis. The δ13Cwsc value in the non-photosynthetic organs were 0.83‰-1.8‰ higher than that in the photosynthetic organs, while the δ13Cwsc value in the aboveground part was generally lower than that in the underground part. As spring progressing, different carbon storage strategies were found between two species. When the terminal bud of P. tabuliformis opened, the carbon was obtained from the proximal old leaves. At the beginning of leaf development, photosynthetic products accumulated by old leaves could not meet the growth requirements for new leaves and roots, with 90% of which depending on the carbon reserve in branches and stems. When full leaf having developed, the photosynthetic function of both new and old leaves recovered and the carbon consumed by branches and stems was gradually replenished. For R. pseudoacacia, at the beginning of leaf bud opening and leaf spreading, branches were the main carbon source for new leaves and roots. When leaves were fully unfolded, mature leaves with high capacity of carbon sequestration became the primary carbon source. Results of principal component analysis showed that temperature during observation period, ≥10 ℃ accumulated temperature, sunshine duration and solar radiation were the main factors influencing δ13Cwsc, which could explained 86.3% of the total variation. The δ13Cwsc values of both species was negatively correlated with temperature and relative humidity, but positively correlated with the difference of saturated water pressure, ≥10 ℃ accumulated temperature and sunshine duration. The main environmental factors affecting plant δ13Cwsc varied during the phenological process. Our results could provide a reference for more accurate estimation of spring organ carbon distribution pattern of regional typical tree species, and also a theoretical basis for formulating scientific and reasonable forest management strategy.


Assuntos
Árvores , Água , Carbono , Isótopos de Carbono , Florestas , Folhas de Planta , Estações do Ano
8.
Environ Pollut ; 281: 117009, 2021 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-33813194

RESUMO

Air pollution caused by PM2.5 particles is a critical issue for public health that adversely affects people living in urban cities. Short-term Mega-events such as international meetings, sports tournaments, and traditional festivals can profoundly influence the local air quality. However, the extent of these influences and their role in improving or deteriorating the local air quality is still unclear. By collecting relative research from 75 publications based on more than 37 cities worldwide, we conducted a systematic review and meta-analysis. We calculated the log response ratio (RR) of the treatment (during) and control periods (before and after) of the Mega-events. The short-term policy control measures enacted during the Mega-Events consisting of meetings caused a significant decline (by -44.06%) in the ambient PM2.5 concentration. The mean daily PM2.5 concentration reduced from more than 100.00 µg/m3 before the events to 60.39 µg/m3, which is below the WHO (World Health Organization) interim target - 1 (75 µg/m3). On the contrary, setting off fireworks during the festival increased the ambient PM2.5 concentrations by 89.57% on average, with a mean daily value of 254.22 µg/m3. The variations in the effects of all event types on the air quality were primarily influenced by the background PM2.5 concentrations, with a negative correlation throughout. Moreover, the impact of events with policy control measures was also influenced by the year of the event, level of control, and location (suburban/urban) of the monitoring sites. Our findings provide evidence of the potential of human intervention on PM2.5 pollution reduction. We further highlight the crucial role of background pollution level in implementing policies during the Mega-events, which can benefit the environmental governance of developing countries.


Assuntos
Poluentes Atmosféricos , Poluição do Ar , Poluentes Atmosféricos/análise , Poluição do Ar/análise , China , Cidades , Conservação dos Recursos Naturais , Monitoramento Ambiental , Política Ambiental , Humanos , Material Particulado/análise
9.
Brain Behav ; 11(4): e02046, 2021 04.
Artigo em Inglês | MEDLINE | ID: mdl-33599398

RESUMO

INTRODUCTION: To explore the changes in C-reactive protein (CRP) level in different regions of one old offspring rats exposed to prenatal stress (PS). METHODS: The rat model was constructed with prenatal restraint stress on pregnant dams on days 14-20 of gestation. Offspring rats were randomly divided into PS susceptibility (PS-S) group and control (CON) group. Behavioral experiments including sucrose preference test (SPT), open-field test (OFT), and forced swimming test (FST) were used to measure depressive-like behaviors. Immunohistochemistry, qRT-PCR, and Western blotting were applied to detect the changes in CRP level. RESULTS: The results showed that PS could cause depressive-like behaviors in all SPT, OFT, and FST. Concomitantly, CRP mRNA and protein expression significantly increased in hippocampus, prefrontal cortex, and hypothalamus in the PS-S group when compared that in the CON group, while no significantly changes in liver, heart, olfactory bulb, striatum, and cerebellum in the PS-S group when compared that in the CON group. CONCLUSION: Increasing of CRP expression in hippocampus, prefrontal cortex, and hypothalamus may play a critical role in the mechanism under depressive-like behavior in offspring rats exposed to PS.


Assuntos
Depressão , Efeitos Tardios da Exposição Pré-Natal , Animais , Comportamento Animal , Depressão/etiologia , Feminino , Hipocampo , Gravidez , Ratos , Ratos Sprague-Dawley , Estresse Psicológico/complicações
11.
Eur J Pharmacol ; 841: 67-74, 2018 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-30336138

RESUMO

Apoptosis of cardiomyocytes and oxidant stress are considered essential processes in the progression of cardiovascular diseases. A hypoxic stress which causes apoptosis of cardiomyocytes is the main problem in ischemic heart disease. The aim of the present study was to explore the functional role and potential mechanisms of miR-223-3p in hypoxia-induced cardiomyocyte apoptosis and oxidative stress. Here, we observed a increment of miR-223-3p level accompanied by the decrease of Krüppel-like zinc-finger transcription factor 15 (KLF15) expression in response to hypoxia. Additionally, absence of miR-223-3p manifestly dampened hypoxia-induced cardiomyocyte injury in H9c2 cells, including improving cell viability, attenuating the LDH leakage and preventing cardiomyocyte apoptosis accompanied by an increase in the expression of Bcl-2 and a decrease in the expression of Bax and C-caspase 3 in the setting of hypoxia. Moreover, depletion of miR-223-3p evidently retarded oxidant stress by inhibiting reactive oxygen species generation and lipid peroxidation, as well as enhancing antioxidant enzyme activity in H9c2 cells following exposure to hypoxia. More importantly, KLF15 was a direct and functional target of miR-223-3p. Further data validated that miR-223-3p negatively regulated the expression of KLF15. Mechanistically, deletion of KLF15 partly abrogated the suppressive effects of miR-223-3p deletion on hypoxia-induced cardiomyocyte apoptosis and oxidative stress. Taken all data together, our findings established that our study defines a novel mechanism by which miR-223-3p protects against cardiomyocyte apoptosis and oxidative stress by targeting KLF15, suggesting that the miR-223-3p/KLF15 may be a potential therapeutic target for ischemic heart conditions.


Assuntos
Apoptose/genética , Fatores de Transcrição Kruppel-Like/genética , MicroRNAs/genética , Miócitos Cardíacos/citologia , Miócitos Cardíacos/metabolismo , Proteínas Nucleares/genética , Estresse Oxidativo/genética , Deleção de Sequência , Sequência de Bases , Hipóxia Celular/genética , Linhagem Celular , Regulação da Expressão Gênica , Humanos , MicroRNAs/metabolismo
12.
Sensors (Basel) ; 17(12)2017 Dec 14.
Artigo em Inglês | MEDLINE | ID: mdl-29240675

RESUMO

The Chinese Gaofen-3 (GF-3) mission was launched in August 2016, equipped with a full polarimetric synthetic aperture radar (SAR) sensor in the C-band, with a resolution of up to 1 m. The absolute positioning accuracy of GF-3 is of great importance, and in-orbit geometric calibration is a key technology for improving absolute positioning accuracy. Conventional geometric calibration is used to accurately calibrate the geometric calibration parameters of the image (internal delay and azimuth shifts) using high-precision ground control data, which are highly dependent on the control data of the calibration field, but it remains costly and labor-intensive to monitor changes in GF-3's geometric calibration parameters. Based on the positioning consistency constraint of the conjugate points, this study presents a geometric cross-calibration method for the rapid and accurate calibration of GF-3. The proposed method can accurately calibrate geometric calibration parameters without using corner reflectors and high-precision digital elevation models, thus improving absolute positioning accuracy of the GF-3 image. GF-3 images from multiple regions were collected to verify the absolute positioning accuracy after cross-calibration. The results show that this method can achieve a calibration accuracy as high as that achieved by the conventional field calibration method.

13.
Water Environ Res ; 87(8): 697-706, 2015 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-26237685

RESUMO

Insoluble organic matter released to the water body through accidental spillage imposes serious damage on the environment. Polypropylene (PP) fiber and methacrylate resin, however, end up in certain morphology or low sorption capacity after a single use. In this study, a novel sorbent was prepared by radiation-induced graft polymerization of butyl methacrylate (BMA) onto PP fiber matrix to retain the advantages of both PP fibers and methacrylate resins to overcome the shortcomings of each used alone. The different parameters including irradiation power, irradiation time and monomer concentration that effect the grafting degree of grafted fiber were studied. The resulting grafted fibers (PP-g-BMA) were evaluated in this study in terms of sorption capacity, retention behaviors and reusability properties. The investigation revealed that the homopolymerization rate, organic matter temperature and pH values of organic-over-water aqueous solution are the most important factors in the sorption performance of polypropylene grafted fiber sorbent.


Assuntos
Metacrilatos/química , Polipropilenos/química , Poluentes Químicos da Água/química , Poluentes Químicos da Água/isolamento & purificação , Adsorção , Concentração de Íons de Hidrogênio , Polimerização , Solubilidade , Temperatura , Raios Ultravioleta
14.
Environ Sci Pollut Res Int ; 22(7): 5139-51, 2015 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-25563832

RESUMO

We analyzed fluctuation in Beijing's air quality over 328 days, based on air quality grades and air quality data from 35 atmospheric monitoring stations. Our results show the air over Beijing is subject to pollution 152 days of the year, or 46.34%. Among all pollutants, fine particulates, solid or liquid, 2.5 µm or less in size (PM2.5), appeared most frequently as the primary pollutant: 249 days, or 76% of the sample year (328 days). Nitrogen dioxide (NO2) and coarse particulates (PM10) cause the least pollution, appearing only 7 and 3 days, or 2 and 1% of the sample year, respectively. In Beijing, fine particulates like PM2.5 vary seasonally: 154.54 ± 18.60 in winter > 145.22 ± 18.61 in spring > 140.16 ± 20.76 in autumn > 122.37 ± 13.42 in summer. Air quality is best in August and worst in December, while various districts in Beijing experience different air quality. To be specific, from south to north and from west to east, air quality tends to improve. Meteorological elements have a constraining effect on air pollutants, which means there is a linear correlation between the air quality index and humidity, rainfall, wind speed, and temperature. Under a typical pollution scenario, the higher the air quality index (AQI) value, the lower the wind speed and the greater the relative humidity; the lower the AQI value, the higher the wind speed and lower the relative humidity. Analysis of influencing factors reveals that the air pollution is mainly particulate matter produced by burning coal, vehicle emissions, volatile oils and gas, fast development of food services, emissions from the surrounding region, and natural dust clouds formed in arid areas to the northwest. Topography affects the distribution of meteorological conditions, in turn varying air quality over the region from one location to another. Human activities also exercise impact on urban air quality with dual functions.


Assuntos
Poluentes Atmosféricos/química , Monitoramento Ambiental/métodos , Material Particulado/análise , Poluição do Ar/análise , China , Cidades , Carvão Mineral/análise , Poeira/análise , Substâncias Perigosas/análise , Humanos , Umidade , Meteorologia , Dióxido de Nitrogênio/análise , Estações do Ano , Temperatura , Emissões de Veículos/análise , Vento
15.
Huan Jing Ke Xue ; 35(5): 1891-900, 2014 May.
Artigo em Chinês | MEDLINE | ID: mdl-25055683

RESUMO

Seasonal variation of heavy metal contents in leaves and their relationships with soil heavy metal pollution levels were studied through measuring and analyzing the leaves of the common tree species in Beijing and soil heavy metal contents, to detect heavy metal accumulation ability of plant leaves. The results showed that: (1) the contents of Cu, Pb, Zn in plant leaves first decreased and then increased, again declined with changing the seasons (from spring to winter). Cr concentration showed the trend of first increase and then decrease from spring to winter, and the highest in the autumn; the accumulation capacities of Cu for Babylonica and Japonica were higher in the spring, summer and autumn, while Tabuliformis was in winter; the higher accumulation capacities for Cr, Pb were Japonica and Platycladus, and in winter were Platycladus and Bungeana; the higher accumulation capacities for Zn were Babylonica and Bungeana, while Platycladus in winter; (2) the pollution degree of four kinds of heavy metals (Cu, Cr, Pb, Zn) from downtown to suburbs showed that: Jingshan (C =2.48, C is contamination factor) > Olympic (C = 1.27) > Songshan (C = 1.20) > Shuiguan (C = 1. 18); (3) the heavy metals concentration of same plant leaves in the water of the Great Wall changed larger, but those in the other three areas showed that: Jingshan > Olympic > Songshan; the ability of same species leaf to absorb different sorts of heavy metals showed that: Zn >Cu >Pb >Cr; the difference between Zn content and Cr content was significant (P <0.01); (4) the relationship between heavy metal content in plant leaves and soil heavy metal pollution levels presented a quadratic polynomial relation; the significant correlation was found between other three heavy metal contents of plant samples and soil samples, but they were not the case for the Cu, and the correlation coefficients were above 0. 9.


Assuntos
Metais Pesados/química , Folhas de Planta/química , Estações do Ano , Poluentes do Solo/química , Árvores/metabolismo , China , Cidades , Monitoramento Ambiental , Solo/química
16.
Ying Yong Sheng Tai Xue Bao ; 24(3): 869-77, 2013 Mar.
Artigo em Chinês | MEDLINE | ID: mdl-23755507

RESUMO

Both inhalable particulate matter (PM10) and fine particulate matter (PM2.5) are not only one of the main causes of air pollution, but also the primary pollutants in most cities. Based on the analysis of the impacts of PM10 and PM2.5 on the environment and human health, this paper summarized the components, sources, and mass concentration variations of PM10 and PM2.5 and related affecting factors, and introduced the network layout of PM10 and PM2.5 monitoring and its principles and features. The research methods on the removal of PM10 and PM2.5 by forests, the removal rates of PM10 and PM2.5 by different forests, and the related affecting mechanisms were summed up at regional and individual scales, and the existed problems in this research field were discussed. Due to the lack of the comparable observation studies on the atmospheric PM10 and PM2.5 along different gradients and in background areas, the joint effects of multiple factors on the PM10 and PM2.5 concentrations are not revealed. It was suggested that to make a rational network layout of PM10 and PM2.5 monitoring, to correctly select proper monitoring methods, and to compare and calibrate the observed results from classical manual methods would be the bases to guarantee the validity of PM10 and PM2.5 monitoring data. At present, there are few reports about the PM2.5 removal by forests, and it's not clear about the physiological processes and ecological mechanisms of PM10 and PM2.5 removal at cell, tissue, organ, and individual level.


Assuntos
Poluentes Atmosféricos/análise , Monitoramento Ambiental/métodos , Material Particulado/análise , Árvores/fisiologia , Biodegradação Ambiental , Tamanho da Partícula
17.
Water Sci Technol ; 66(12): 2647-52, 2012.
Artigo em Inglês | MEDLINE | ID: mdl-23109581

RESUMO

In order to improve oil sorption performances, polypropylene (PP) fiber was modified through graft polymerization with butyl acrylate (BA) initiated by ultraviolet (UV) radiation in isopropanol/water mixture solution. Fourier transform infrared (FT-IR) spectra, scanning electron microscopy (SEM) and specific surface area were used to characterize the chemical and morphological changes of the PP fiber surface. Static contact angle (CA) measurements showed that the hydrophilicity of original PP fiber was enhanced after graft polymerization. The grafted fiber exhibited an excellent oil-sorption, oil-retention performance, fast saturation-sorption rate and superior reusability of oil. When the grafting degree was 15.55%, the maximum oil-sorption capacity reached 18.35 g/g, while the oil-sorption capacity of original PP fiber was only 11.54 g/g. After the tenth cycle of reuse, the grafted fiber sorbent assembly only lost 30% of its virgin sorption capacity.


Assuntos
Acrilatos/química , Óleos/isolamento & purificação , Polimerização/efeitos da radiação , Polipropilenos/química , Raios Ultravioleta , Adsorção/efeitos da radiação , Microscopia Eletrônica de Varredura , Reciclagem , Espectroscopia de Infravermelho com Transformada de Fourier , Propriedades de Superfície/efeitos da radiação , Fatores de Tempo
18.
Water Environ Res ; 84(9): 719-24, 2012 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-23012771

RESUMO

To solve water pollution caused by oil spillage, a new sorbent was prepared by radiation-induced graft polymerization. Acrylate monomer was introduced to polypropylene nonwoven and hydrophobic groups were introduced by the grafting method. The grafting degree of sorbent was determined as a function of monomer concentration and solvent solubility for monomer. Fourier transform-infrared spectra and static contact angle measurements were used to characterize the chemical changes of the polypropylene nonwoven surface. The grafted sorbent showed a fast sorption rate and a maximum sorption capacity of 13.56 g/g for diesel oil, while the original polypropylene nonwoven was only 7.48 g/g. In addition, retention measurement and the reusability test were conducted to evaluate the suitability of the polypropylene-acrylate grafted nonwoven for the treatment of oil spillage.


Assuntos
Acrilatos/química , Recuperação e Remediação Ambiental/métodos , Gasolina , Polipropilenos/química , Poluentes Químicos da Água/isolamento & purificação , Reciclagem , Espectroscopia de Infravermelho com Transformada de Fourier , Xilenos/química
19.
Mar Pollut Bull ; 64(6): 1172-6, 2012 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-22503098

RESUMO

Lauryl acrylate (LA) grafted polypropylene (PP) fibers (PP-g-LA) were prepared via ultraviolet radiation and used to adsorb insoluble organics from aqueous solutions. The grafted fibers showed a maximum adsorption capacity of 18.85 g/g for benzene, while the adsorption capacity of the original PP fiber was only 8.21 g/g. However, graft polymerization is usually accompanied by the homopolymerization phenomenon, which is detrimental to practical applications of the grafted fiber. Homopolymerization negatively affected the adsorption capacities and the reusabilities of the grafted fibers, which decreased with increasing rates of homopolymerization. The adsorption capacity of grafted fiber with a homopolymerization rate of 18.40% was maintained above 85% of its initial adsorption capacity after being regenerated 10 times, while the adsorption capacity of the grafted fiber with a homopolymerization rate of 70.51% was approximately 40% of its initial capacity after 10 regenerations.


Assuntos
Recuperação e Remediação Ambiental/métodos , Polipropilenos/química , Poluentes Químicos da Água/análise , Adsorção , Vazamento de Resíduos Químicos , Polimerização , Raios Ultravioleta , Poluentes Químicos da Água/química , Purificação da Água/métodos
20.
Sci China C Life Sci ; 51(7): 662-70, 2008 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-18622750

RESUMO

Evaluation of forest ecosystem services is a hot topic, both in China and at abroad, but it has not yet obtained a consistency of evaluation indicator systems and evaluation methods. Under the framework of evaluation criteria to be implemented for forest ecosystem services, years of consecutive observation data from Long Term Ecological Research Stations affiliated to Chinese Forest Ecosystem Research Network (CFERN), forest resource inventory and public data were applied to carry out a detailed and dynamic evaluation on the physical quantity and value of ecosystem services of Chinese pine forests in China. The results showed that the above services had the total value and unit value of 1144.9640 billion (1.1449640x10(12)) RMB and 52.074 thousand RMB per hectare per year, respectively during the 9th Five-year Plan (1996-2000), and of 1190.5461 billion RMB and 52.101 thousand RMB per hectare per year, respectively, during the 10th Five-year Plan (2001-2005). For Chinese pine forests, water conservation was 40.40 hundred million cubic meters annually, soil conservation was 67 million tons and C fixation 9 million tons annually, production of healthful negative ions was 1.96x10(20), absorption of SO(2) was 5.02 hundred million kilograms and dust-catching was 759.10 hundred million kilograms. Among the 15 provinces of China with Chinese pine forests, the biggest beneficiary from ecosystem services was Liaoning Province; while Hunan Province was the smallest beneficiary between the 9th Five-year Plan.


Assuntos
Ecossistema , Pinus/fisiologia , Árvores/fisiologia , China , Fatores de Tempo
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