Your browser doesn't support javascript.
loading
Montrer: 20 | 50 | 100
Résultats 1 - 15 de 15
Filtrer
1.
RSC Adv ; 14(21): 14784-14792, 2024 May 02.
Article de Anglais | MEDLINE | ID: mdl-38716103

RÉSUMÉ

Volatile organic compounds (VOCs) originating from diverse sources with complex compositions pose threats to both environmental safety and human health. Photocatalytic treatment of VOCs has garnered attention due to its high efficacy at room temperature. However, the intricate photochemical reaction generates ozone (O3), causing secondary pollution. Herein, our work developed a novel "synergistic effect" system for photocatalytic co-treatment of VOCs and O3 secondary pollution. Under the optimized reactor conditions simulated with computational fluid dynamics (CFD), MgO-loaded g-C3N4 composites (MgO/g-C3N4) were synthesized as efficient catalysts for the photocatalytic synergistic treatment process. Density functional theory (DFT) calculations, characterization, and electron paramagnetic resonance (EPR) tests revealed that the addition of MgO reduced the band gap of g-C3N4, and increased O3 molecule adsorption in the composites, efficiently harnessing the synergistic effect of O3 to generate a significant quantity of reactive oxygen radicals, thereby facilitating the removal of VOCs and O3. This study provides new insights for simultaneous elimination of VOCs and O3 secondary pollution by a photocatalytic process.

2.
Geohealth ; 8(5): e2024GH001025, 2024 May.
Article de Anglais | MEDLINE | ID: mdl-38784719

RÉSUMÉ

Although the World Health Organization has declared that the COVID-19 pandemic no longer qualifies as a global public health emergency, it still needs to explore the response of society to the COVID-19 pandemic. Socio-economic status (SES) was proven to be linearly associated with the COVID-19 pandemic, although this relationship may be more complex due to regional differences. In the study, we analyzed and revealed the effects and mechanisms of SES on infections among low, lower-middle, upper-middle and high SES group (LSG, LMSG, UMSG, and HSG, respectively). The results showed that the relationship between SES and infections was inverted U-shaped, especially in the first three phases. In Phase I, UMSG had the highest number of infections, with an average of 238.31/1M people (95%CI: 135.47-341.15/1M people). In Phases II and III, infections decreased insignificantly with increasing SES (r = -0.01, p = 0.92; r = -0.11, p = 0.22) and the highest number of infections were found in the LMSG. In Phase IV, SES was positively related to the number of infections (r = 0.54, p < 0.001). Furthermore, the nonlinear impact of multiple factors related to SES on the infections explains the complex relationships between SES and infections. SES affected infections mainly through medical resources, demographics and vaccination, and differed across the SES groups. Particularly, demographics could exert an impact on population mobility, subsequently influencing infections in LMSG, with an indirect effect of 0.01 (p < 0.05) in Phase II. This study argues for greater attention to countries with middle SES and the need for future targeted measures to cope with infectious diseases.

3.
Sci Data ; 10(1): 900, 2023 Dec 15.
Article de Anglais | MEDLINE | ID: mdl-38102189

RÉSUMÉ

For the ecologically vulnerable Qinghai-Tibet Plateau (QTP), hypoxia is increasingly becoming an extremely important environmental risk factor that significantly affects the health of both humans and livestock in the plateau region, as well as hindering high-quality development. To focus on the problem of hypoxia, it is especially urgent to study the surface oxygen concentration (i.e., oxygen concentration). However, the existing research is not sufficient, and there is a lack of oxygen concentration data collected on the QTP. In this study, through the Second Tibetan Plateau Scientific Expedition and Research and field measurements, the oxygen concentration data and corresponding geographic environmental data were collected at 807 measurement points on the QTP from 2017 to 2022, and the spatiotemporal oxygen concentration patterns were estimated. This work filled the gaps in the measurement and research of oxygen concentrations on the QTP while providing data support for analyses of the influencing factors and spatiotemporal characteristics of oxygen concentrations, which is of great significance for promoting the construction of ecological civilization in the QTP region.

4.
Heliyon ; 9(7): e17746, 2023 Jul.
Article de Anglais | MEDLINE | ID: mdl-37456022

RÉSUMÉ

Air quality prediction is a typical Spatiotemporal modeling problem, which always uses different components to handle spatial and temporal dependencies in complex systems separately. Previous models based on time series analysis and recurrent neural network (RNN) methods have only modeled time series while ignoring spatial information. Previous graph convolution neural networks (GCNs) based methods usually require providing spatial correlation graph structure of observation sites in advance. The correlations among these sites and their strengths are usually calculated using prior information. However, due to the limitations of human cognition, limited prior information cannot reflect the real station-related structure or bring more effective information for accurate prediction. To this end, we propose a novel Dynamic Graph Neural Network with Adaptive Edge Attributes (DGN-AEA) on the message passing network, which generates the adaptive bidirected dynamic graph by learning the edge attributes as model parameters. Unlike prior information to establish edges, our method can obtain adaptive edge information through end-to-end training without any prior information. Thus reducing the complexity of the problem. Besides, the hidden structural information between the stations can be obtained as model by-products, which can help make some subsequent decision-making analyses. Experimental results show that our model received state-of-the-art performance than other baselines.

6.
Sci Total Environ ; 838(Pt 1): 156023, 2022 Sep 10.
Article de Anglais | MEDLINE | ID: mdl-35595142

RÉSUMÉ

Great attention has been paid to the long-term decline in terrestrial near-surface wind speed (SWS) in China. However, how the SWS varies with regions and seasons and what modulates these changes remain unclear. Based on quality-controlled and homogenized terrestrial SWS data from 596 stations, the covarying SWS patterns during the Asian Summer Monsoon (ASM) and the Asian Winter Monsoon (AWM) seasons are defined for China using empirical orthogonal function (EOF) analysis for 1961-2016. The dominant SWS features represented by EOF1 patterns in both seasons show a clear decline over most regions of China. The interannual variability of the EOF1 patterns is closely related to the Northeast Asia Low Pressure (NEALP) and the Arctic Oscillation (AO), respectively. The EOF2 and EOF3 patterns during ASM (AWM) season describe a dipole mode of SWS between East Tibetan Plateau and East China Plain (between East Tibetan Plateau and Northeast China), and between Southeast and Northeast China (between Northeast China and the coastal areas of Southeast China), respectively. These dipole structures of SWS changes are closely linked with the oceanic-atmospheric oscillations on interannual scale.


Sujet(s)
Surveillance de l'environnement , Vent , Chine , Océans et mers , Saisons
7.
Sci Rep ; 11(1): 17338, 2021 08 30.
Article de Anglais | MEDLINE | ID: mdl-34462465

RÉSUMÉ

Oxygen (O2) is the most abundant molecule in the atmosphere after nitrogen. Previous studies have documented that oxygen concentration remains nearly constant (20.946%) at all altitudes. Here we show for the first time that oxygen concentration varies significantly from earlier consensus and shows strong spatial and seasonal differences. Field observations on the Qinghai-Tibetan Plateau (QTP) indicate oxygen concentration of 19.94-20.66% (2018, n = 80), 19.98-20.78% (2019, n = 166) and 19.97-20.73% (2020, n = 176), all statistically different from earlier reports (p < 0.001) and are lower than the nearly constant. The mean oxygen concentration in summer (20.47%) is 0.31% higher than that of winter (20.16%) (n = 53) at identical locations in 2019, sampled in the Qilian Mountains, northwest QTP. We used LMG (The Lindeman, Merenda and Gold) method to estimate the relative contributions of altitude, air temperature and vegetation index (Fractional Vegetation Cover, FVC and Leaf Area Index, LAI) to oxygen concentration, which are 47%, 32% and 3% (FVC, R2 = 82%); 45%, 30% and 7% (LAI, R2 = 82%), respectively. These findings provide a new perspective for in-depth understanding on population risk in high altitude regions in the context of global climate change, to ensure the health and safety of residents and tourists in high altitude regions and promoting the stability, prosperity and sustainable development of high-altitude regions worldwide.

8.
Oncol Lett ; 8(4): 1543-1550, 2014 Oct.
Article de Anglais | MEDLINE | ID: mdl-25202365

RÉSUMÉ

Prognostic markers for colorectal cancer (CRC) have not yet been fully investigated. Phosphatase and tensin homolog (PTEN), p27 and Cyclin D1 play significant roles in tumorigenesis and cell cycle regulation, and therefore require evaluation for their prognostic value in this disease. The aim of the present study was to assess the prognostic value of the single and combined expression of PTEN, p27 and Cyclin D1 in CRC patients. Protein expression levels of PTEN, p27 and Cyclin D1 were examined by immunohistochemistry from 61 patients with CRC in either stage II or III. In the CRC tissues, the frequencies of PTEN(-), p27(-) and Cyclin D1(+) expression were 42.62% (26/61), 32.79% (20/61) and 45.90% (28/61), respectively. Depletion of PTEN and p27 was more common with respect to stage III, low grade and lymph node metastasis compared with stage II, moderate grade and no lymph node metastasis (P<0.05). Cyclin D1-positive expression was frequently detected in CRC of stage III, with lymph node metastasis and deeper invasion (P<0.05). The depletion of PTEN was significantly correlated with the loss of p27 (P<0.001) and with the increased expression of Cyclin D1 (P<0.001). PTEN(-) and/or p27(-) expression was significantly correlated with Cyclin D1(+) expression (P<0.05). Combined PTEN(-)/p27(-)/Cyclin D1(+) expression was correlated with a significant decrease in overall survival time (P<0.05). Combined p27(-) and Cyclin D1(+) expression indicated a worse overall survival time than other combined expression patterns. These findings indicate that the single expression of PTEN(-), p27(-) and Cyclin D1(+) and the combined detection of p27(-) and Cyclin D1(+) may be used as prognostic markers for overall survival time in CRC.

9.
Huan Jing Ke Xue ; 35(5): 1623-32, 2014 May.
Article de Chinois | MEDLINE | ID: mdl-25055647

RÉSUMÉ

The emission characteristics of five typical crops, including wheat straw, rice straw, oil rape straw, soybean straw and fuel wood, were investigated to explore the gas and particulates emission of typical biomass burning in Yangzi-River-Delta area. The straws were tested both by burning in stove and by burning in the farm with a self-developed measurement system as open burning sources. Both gas and fine particle pollutants were measured in this study as well as the chemical composition of fine particles. The results showed that the average emission factors of CO, NO, and PM2,5 in open farm burning were 28.7 g.kg -1, 1.2 g.kg-1 and 2.65 g kg-1 , respectively. Due to insufficient burning in the low oxygen level environment, the emission factors of stove burning were higher than those of open farm burning, which were 81.9 g kg-1, 2. 1 g.kg -1 and 8.5 gkg -1 , respectively. Oil rape straw had the highest emission factors in all tested straws samples. Carbonaceous matter, including organic carbon(OC) and element carbon(EC) , was the foremost component of PM2, 5from biomass burning. The average mass fractions of OC and EC were (38.92 +/- 13.93)% and (5.66 +/-1.54)% by open farm burning and (26.37 +/- 10. 14)% and (18.97 +/- 10.76)% by stove burning. Water soluble ions such as Cl-and K+ had a large contribution. The average mass fractions of CI- and K+ were (13.27 +/-6. 82)% and (12.41 +/- 3.02)% by open farm burning, and were (16.25 +/- 9.34)% and (13.62 +/- 7.91)% by stove burning. The K +/OC values of particles from wheat straw, rice straw, oil rape straw and soybean straw by open farm burning were 0. 30, 0. 52, 0. 49 and 0. 15, respectively, which can be used to evaluate the influence on the regional air quality in YRD area from biomass burning and provide direct evidence for source apportionment.


Sujet(s)
Polluants atmosphériques/analyse , Biomasse , Surveillance de l'environnement , Incinération , Matière particulaire/analyse , Carbone/analyse , Chine , Produits agricoles , Rivières
10.
Huan Jing Ke Xue ; 35(5): 1644-53, 2014 May.
Article de Chinois | MEDLINE | ID: mdl-25055649

RÉSUMÉ

A continuous air quality observation was conducted in the urban area of Shanghai from April 28 to May 18 in 2011. The mass concentration of particle matters and main chemical compositions of fine particle were measured and analyzed. The mass concentrations of PM10 and PM2.5 during the dust episode were much higher than those in non-dust episode, with the maximum daily mass concentrations of PM10 and PM2.5 reaching 787.2 microg.gm-3 and 139.5 microgm(-3) , respectively. The average PM2.5 /PM10 ratio was (32.9 +/-14. 6)% (15. 6% -85.1% ). The total water soluble inorganic ions(TWSII ) contributed (27.2 +/- 19. 2)% (4. 8% -80. 8% ) of total PM2.5, and the secondary water soluble ions (SNA) , including SO(2-)4 , NO-(3) and NH(+)(4) , were (76.9 +/- 13.9)% (41.9%-94.2%) in TWSIl. The concentrations of TWSII and SNA in PM2.5 during dust days became lower than those in non-dust days while the trend of the ratio of Ca2+ to PM2.5, increased. The mean OC/EC value in non-dust days was higher than that in the heavy dust pollution episode, but lower than that in weak dust days. In addition, mineral-rich particle in dust period had an acid-buffer effect, making particle alkaline in dust days stronger. In non-dust days, SO(2-)(4) and NO(-)(3) mainly existed in the form of NH4HSO4, (NH4)SO4, and NH4NO3, and combined with other mineral ions during dust days.


Sujet(s)
Polluants atmosphériques/analyse , Poussière/analyse , Surveillance de l'environnement , Matière particulaire/analyse , Chine , Villes , Ions/analyse , Taille de particule , Saisons
11.
Huan Jing Ke Xue ; 33(4): 1071-9, 2012 Apr.
Article de Chinois | MEDLINE | ID: mdl-22720548

RÉSUMÉ

Light-duty gasoline taxis (LDGT) and passenger cars (LDGV), heavy-duty diesel buses (HDDB) and trucks (HDDT), gasoline motorcycles (MC) and LPG scooters (LPGS), were selected for tailpipe volatile organic compounds (VOCs) samplings by using transient dynamometer and on road test combined with SUMMA canisters technology. The samples were tested by GC-MS to analyze the concentration and species composition of VOCs. The results indicate that light-duty gasoline automobiles have higher fractions of aromatic hydrocarbons, which account for 43.38%-44.45% of the total VOCs, the main aromatic hydrocarbons are toluene and xylenes. Heavy-duty diesel vehicles have higher fractions of alkanes, which constitute 46.86%-48.57% of the total VOCs, the main alkanes are propane, n-dodecane and n-undecane. In addition, oxy-organics account for 13.28%-15.01% of the VOCs, the main oxy-organics is acetone. The major compound from MC and LPGS exhaust is acetylene, it accounts for 39.75% and 76.67% of the total VOCs, respectively. VOCs exhaust from gasoline motorcycles and light-duty gasoline automobiles has a significantly higher chemical reactivity than those from heavy-duty diesel vehicles, which contribute 55% and 44% to the atmospheric chemical reactivity in Shanghai. The gasoline motorcycles and light-duty gasoline automobiles are the key pollution sources affecting city and region ambient oxidation, and the key active species of toluene, xylenes, propylene, and styrene make the greatest contribution.


Sujet(s)
Polluants atmosphériques/analyse , Emissions des véhicules/analyse , Composés organiques volatils/analyse , Alcènes/analyse , Chine , Villes , Surveillance de l'environnement , Toluène/analyse , Composés organiques volatils/composition chimique , Xylènes/analyse
12.
Huan Jing Ke Xue ; 33(12): 4151-8, 2012 Dec.
Article de Chinois | MEDLINE | ID: mdl-23379136

RÉSUMÉ

The emission strength of VOCs was estimated in the study, based on the volatile organic compounds (VOCs) measurement results. Air mass backward trajectories were computed and cluster analysis was done combining with the corresponding air pollution indexes and VOCs concentrations. Source apportionment of VOCs was studied using receptor model. According to this study, VOCs emission in Shanghai per hour resulted in the VOCs concentration increment of (5.98 +/- 3.18) x 10(-9) during 2010 EXPO (from 1st May to 31st October in 2010), which was decreased by about 1 x 10(-9) compared to that in the same period of 2009. Under the control of the air masses roughly from the east (40%), the API was lower than 50. Influenced by the air masses from the northwest, the air quality was the worst with the average API higher than 70. The air masses from the southwest also resulted in bad air quality, with API higher than 60. The air masses originated from the west accounted for 25%, followed by the south and north air mass (20%). The VOCs concentrations were positively related to API in the same air mass, R2 = 0.599. During the 2010 EXPO, the emission related to vehicles including exhaust and gasoline evaporation contributed the largest amount of VOCs, approximately about -40%, followed by industry including industrial processes and coal combustion (30% - 40%), and solvent use and painting (20%). The biogenic emission was also considerable and accounted for 6% of VOCs in summer.


Sujet(s)
Polluants atmosphériques/analyse , Surveillance de l'environnement , Emissions des véhicules/analyse , Composés organiques volatils/analyse , Chine , Charbon
13.
J Environ Sci (China) ; 23(7): 1150-7, 2011.
Article de Anglais | MEDLINE | ID: mdl-22125908

RÉSUMÉ

Ozone has become one of the most important air pollution issues around the world. This article applied both O3/(NO(y)-NO(x)) and H2O2/HNO3 indicators to analyze the ozone sensitivity in urban and rural areas of Shanghai, with implementation of the MM5-CMAQ modeling system in July, 2007. The meteorological parameters were obtained by using the MM5 model. A regional emission inventory with spatial and temporal allocation based on the statistical data has been developed to provide input emission data to the MM5-CMAQ modeling system. Results showed that the ozone concentrations in Shanghai show clear regional differences. The ozone concentration in rural areas was much higher than that in the urban area. Two indicators showed that ozone was more sensitive to VOCs in urban areas, while it tended to be NO(x) sensitive in rural areas of Shanghai.


Sujet(s)
Surveillance de l'environnement/méthodes , Ozone/analyse , Chine , Géographie
14.
Gastroenterol Nurs ; 33(4): 313-7, 2010.
Article de Anglais | MEDLINE | ID: mdl-20679784

RÉSUMÉ

Gastric lymphoma is characterized by a good prognosis with slow progression and a nonspecific appearance under the endoscope. A biopsy is performed for accurate diagnosis. For this study, endoscopy and biopsy specimens were analyzed retrospectively to investigate the rate of accurate diagnosis of gastric lymphoma in first-, second-, and third-round endoscopic and biopsy procedures and to understand the causes of discrepancies. Fifty-four cases of gastric lymphoma were diagnosed in 32,000 patients. The rate of positive Helicobacter pylori infection was 70.4%. Of these, 13 cases were diffuse large B-cell lymphoma and 41 cases were marginal zone B-cell lymphoma. Thirty-two gastric lymphoma cases (59.3%) were diagnosed by first-round endoscopy and biopsy, 13 (24.1%) cases required second-round endoscopy and biopsy, and 9 (16.7%) cases were determined in the third round of endoscopic and biopsy procedures. Repeating endoscopy and biopsy reduced discrepancies in the diagnosis of gastric lymphoma by 40.8%, which can significantly improve the overall accuracy of diagnosis and treatment of gastric lymphoma.


Sujet(s)
Biopsie/méthodes , Erreurs de diagnostic/prévention et contrôle , Gastroscopie/méthodes , Lymphomes/anatomopathologie , Tumeurs de l'estomac/anatomopathologie , Adulte , Sujet âgé , Sujet âgé de 80 ans ou plus , Erreurs de diagnostic/statistiques et données numériques , Femelle , Humains , Mâle , Microscopie , Adulte d'âge moyen , Études rétrospectives , Sensibilité et spécificité
15.
Huan Jing Ke Xue ; 30(10): 2816-22, 2009 Oct 15.
Article de Chinois | MEDLINE | ID: mdl-19968092

RÉSUMÉ

Applying the volume data of dominant trees from statistics on the national forest resources, volatile organic compounds (VOC) emissions of each main tree species in China were estimated based on the light-temperature model put forward by Guenther. China's VOC emission inventory for forest was established, and the space-time and age-class distributions of VOC emission were analyzed. The results show that the total VOC emissions from forests in China are 8565.76 Gg, of which isoprene is 5689.38 Gg (66.42%), monoterpenes is 1343.95 Gg (15.69%), and other VOC is 1532.43 Gg (17.89%). VOC emissions have significant species variation. Quercus is the main species responsible for emission, contributing 45.22% of the total, followed by Picea and Pinus massoniana with 6.34% and 5.22%, respectively. Southwest and Northeast China are the major emission regions. In specific, Yunnan, Sichuan, Heilongjiang, Jilin and Shaanxi are the top five provinces producing the most VOC emissions from forests, and their contributions to the total are 15.09%, 12.58%, 10.35%, 7.49% and 7.37%, respectively. Emissions from these five provinces occupy more than half (52.88%) of the national emissions. Besides, VOC emissions show remarkable seasonal variation. Emissions in summer are the largest, accounting for 56.66% of the annual. Forests of different ages have different emission contribution. Half-mature forests play a key role and contribute 38.84% of the total emission from forests.


Sujet(s)
Polluants atmosphériques/analyse , Arbres/métabolisme , Composés organiques volatils/analyse , Chine , Modèles théoriques , Picea/métabolisme , Pinus/métabolisme , Quercus/métabolisme , Spécificité d'espèce , Arbres/classification
SÉLECTION CITATIONS
DÉTAIL DE RECHERCHE
...