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1.
Huan Jing Ke Xue ; 40(11): 4810-4823, 2019 Nov 08.
Artigo em Chinês | MEDLINE | ID: mdl-31854546

RESUMO

Northeastern China experiences severe atmospheric pollution, with an increasing occurrence of heavy haze episodes. Based on ground monitoring data, satellite products and meteorological products of atmospheric pollutants in northeast China from 2013 to 2017, the characteristics of spatial and temporal distribution of air quality and the causes of heavy haze events in northeast China were discussed. It was found that the "Shenyang-Changchun-Harbin" city belt was the most polluted area in the region on an annual scale. The spatial distribution of air quality index (AQI) values had a clear seasonality, with the worst pollution occurring in winter, an approximately oval-shaped polluted area around western Jilin Province in spring, and the best air quality occurring in summer and most of autumn. The three periods that typically experienced intense haze events were Period I from late-October to early-November (i. e., late autumn and early winter), Period Ⅱ from late-December to January (i. e., the coldest time in winter), and Period Ⅲ from April to mid-May (i. e., spring). During Period I, strong PM2.5 emissions from seasonal crop residue burning and coal burning for winter heating were the dominant reasons for the occurrence of extreme haze events (AQI>300). Period Ⅱ had frequent heavy haze events (200 < AQI < 300) in the coldest months of January and February(200 < AQI < 300), which were due to high PM2.5 emissions from coal burning and vehicle fuel consumption, a lower atmospheric boundary layer, and stagnant atmospheric conditions. Haze events in Period Ⅲ, with high PM10 concentrations, were primarily caused by the regional transportation of windblown dust from degraded grassland in central Inner Mongolia and bare soil in western Jilin Province. Local agricultural tilling could also release PM10 and enhance the levels of windblown dust from tilled soil.

2.
Huan Jing Ke Xue ; 40(8): 3438-3446, 2019 Aug 08.
Artigo em Chinês | MEDLINE | ID: mdl-31854748

RESUMO

Organic aerosols have attracted increasing attention recently due to their significant contribution to fine particles (PM2.5) and their complex components and sources. In this study, a total of 40 PM2.5 samples were collected simultaneously with high-volume samplers in Changchun from 16th Oct to 29th Nov 2016. Organic carbon (OC), elemental carbon (EC), non-polar organic compounds including n-alkanes, polycyclic aromatic hydrocarbons (PAHs), and hopanes, and levoglucosan in atmospheric fine particles were analyzed. The main sources of organic aerosols were identified by molecular markers, diagnostic ratios, and a principal component analysis-multiple liner regression (PCA-MLR) model. The results showed that the average mass concentration of PM2.5 was (79.0±55.7) µg·m-3, and the averaged OC and EC mass concentrations were (20.7±15.6) µg·m-3 and (2.2±1.1) µg·m-3, which accounted for 26.2% and 2.8% of PM2.5, respectively. The total average concentration of the tested non-polar organic compounds was (186.3±104.5) ng·m-3 and, in descending order, this was composed of n-alkane (101.3±67.0) ng·m-3, polycyclic aromatic hydrocarbons (81.4±46.0) ng·m-3, hopanes (3.8±1.9) ng·m-3. The PCA-MLR model results showed that the relative contributions of the main sources of organic aerosols were coal combustion (47.0%), biomass burning (42.6%), and traffic emission (10.4%).

3.
Environ Pollut ; 231(Pt 1): 654-662, 2017 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-28846986

RESUMO

Fine particulate matter (PM2.5) samples were collected using a high-volume air sampler and pre-combusted quartz filters during May 2013 to January 2014 at a background rural site (47∘35 N, 133∘31 E) in Sanjiang Plain, Northeast China. A homologous series of dicarboxylic acids (C2-C11) and related compounds (oxoacids, α-dicarbonyls and fatty acids) were analyzed by using a gas chromatography (GC) and GC-MS method employing a dibutyl ester derivatization technique. Intensively open biomass-burning (BB) episodes during the harvest season in fall were characterized by high mass concentrations of PM2.5, dicarboxylic acids and levoglucosan. During the BB period, mass concentrations of dicarboxylic acids and related compounds were increased by up to >20 times with different factors for different organic compounds (i.e., succinic (C4) acid > oxalic (C2) acid > malonic (C3) acid). High concentrations were also found for their possible precursors such as glyoxylic acid (ωC2), 4-oxobutanoic acid, pyruvic acid, glyoxal, and methylglyoxal as well as fatty acids. Levoglucosan showed strong correlations with carbonaceous aerosols (OC, EC, WSOC) and dicarboxylic acids although such good correlations were not observed during non-biomass-burning seasons. Our results clearly demonstrate biomass burning emissions are very important contributors to dicarboxylic acids and related compounds. The selected ratios (e.g., C3/C4, maleic acid/fumaric acid, C2/ωC2, and C2/levoglucosan) were used as tracers for secondary formation of organic aerosols and their aging process. Our results indicate that organic aerosols from biomass burning in this study are fresh without substantial aging or secondary production. The present chemical characteristics of organic compounds in biomass-burning emissions are very important for better understanding the impacts of biomass burning on the atmosphere aerosols.


Assuntos
Poluentes Atmosféricos/análise , Ácidos Dicarboxílicos/análise , Monitoramento Ambiental , Material Particulado/análise , Aerossóis/análise , Atmosfera/química , Biomassa , China , Compostos Orgânicos/análise , Estações do Ano
4.
J Environ Sci (China) ; 54: 101-113, 2017 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-28391918

RESUMO

This study presents the mass concentrations of PM2.5, O3, SO2 and NOx at one urban, one suburban and two rural locations in the Changchun region from September 25 to October 27 2013. Major chemical components of PM2.5 at the four sites were daily sampled and analyzed. Most of daily concentrations of SO2 (7-82µg/m3), O3 (27-171µg/m3) and NOx (14-213µg/m3) were below the limits of the National Ambient Air Quality Standard (NAAQS) in China. However, PM2.5 concentrations (143-168µg/m3) were 2-fold higher than NAAQS. Higher PM2.5 concentrations (~150µg/m3) were measured during the pre-harvest and harvest at the urban site, while PM2.5 concentrations significantly increased from 250 to 400µgm-3 at suburban and rural sites with widespread biomass burning. At all sites, PM2.5 components were dominated by organic carbon (OC) and followed by soluble component sulfate (SO42-), ammonium (NH4+) and nitrate (NO3-). Compared with rural sites, urban site had a higher mineral contribution and lower potassium (K+ and K) contribution to PM2.5. Severe atmospheric haze events that occurred from October 21 to 23 were attributed to strong source emissions (e.g., biomass burning) and unfavorable air diffusion conditions. Furthermore, coal burning originating from winter heating supply beginning on October 18 increased the atmospheric pollutant emissions. For entire crop harvest period, the Positive Matrix Factorization (PMF) analysis indicated five important emission contributors in the Changchun region, as follows: secondary aerosol (39%), biomass burning (20%), supply heating (18%), soil/road dust (14%) and traffic (9%).


Assuntos
Poluentes Atmosféricos/análise , Poluição do Ar/estatística & dados numéricos , Poeira/análise , Monitoramento Ambiental , Aerossóis/análise , Agricultura , China , Material Particulado/análise
5.
Brain Res ; 1653: 67-74, 2016 12 15.
Artigo em Inglês | MEDLINE | ID: mdl-27769787

RESUMO

Cilostazol(CTL) is a phosphodiesterase inhibitor, which has been widely used as anti-platelet agent. It also has preventive effects on various central nervous system (CNS) diseases, including ischemic stroke, Parkinson's disease and Alzheimer disease. However, the molecular mechanism underlying the protective effects of CTL is still unclear, and whether CTL can prevent I/R induced cognitive deficit has not been reported. Transient global brain ischemia was induced by 4-vessel occlusion in adult male Sprague-Dawley rats. The open field tasks and Morris water maze were used to assess the effect of CTL on anxiety-like behavioral and cognitive impairment after I/R. Western blotting were performed to examine the expression of related proteins, and HE-staining was used to detect the percentage of neuronal death in the hippocampal CA1 region. Here we found that CTL significantly improved cognitive deficits and the behavior of rats in Morris water maze and open field tasks (P<0.05). HE staining results showed that CTL could significantly protect CA1 neurons against cerebral I/R (P<0.05). Additionally, Akt1 phosphorylation levels were evidently up-regulated (P<0.05), while the activation of JNK3, which is an important contributor to I/R-induced neuron apoptosis, was reduced by CTL after I/R (P<0.05), and caspase-3 levels were also decreased by CTL treatment. Furthermore, all of CTL's protective effects were reversed by LY294002, which is a PI3K/Akt1 inhibitor. Taken together, our results suggest that CTL could protect hippocampal neurons and ameliorate the impairment of learning/memory abilities and locomotor/ exploratory activities in ischemic stroke via a PI3K-Akt1/JNK3/caspase-3 dependent mechanism.


Assuntos
Isquemia Encefálica/tratamento farmacológico , Transtornos Cognitivos/tratamento farmacológico , Hipocampo/efeitos dos fármacos , Fármacos Neuroprotetores/farmacologia , Traumatismo por Reperfusão/tratamento farmacológico , Tetrazóis/farmacologia , Animais , Apoptose/efeitos dos fármacos , Apoptose/fisiologia , Isquemia Encefálica/complicações , Isquemia Encefálica/enzimologia , Isquemia Encefálica/patologia , Caspase 3/metabolismo , Cilostazol , Transtornos Cognitivos/enzimologia , Transtornos Cognitivos/etiologia , Transtornos Cognitivos/patologia , Modelos Animais de Doenças , Avaliação Pré-Clínica de Medicamentos , Inibidores Enzimáticos/farmacologia , Hipocampo/enzimologia , Hipocampo/patologia , Masculino , Proteína Quinase 10 Ativada por Mitógeno/antagonistas & inibidores , Proteína Quinase 10 Ativada por Mitógeno/metabolismo , Neurônios/efeitos dos fármacos , Neurônios/enzimologia , Neurônios/patologia , Fosforilação/efeitos dos fármacos , Proteínas Proto-Oncogênicas c-akt/antagonistas & inibidores , Proteínas Proto-Oncogênicas c-akt/metabolismo , Ratos Sprague-Dawley , Traumatismo por Reperfusão/complicações , Traumatismo por Reperfusão/enzimologia , Traumatismo por Reperfusão/patologia
6.
Mitochondrial DNA A DNA Mapp Seq Anal ; 27(6): 4284-4285, 2016 11.
Artigo em Inglês | MEDLINE | ID: mdl-26369669

RESUMO

The Fossorochromis rostratus is a species of cichlid endemic to Lake Malawi in East Africa. In this study, we first reported the complete mitochondrial genome of F. rostratus. The whole mitochondrial genome is 16 581 bp in length, which contains 13 protein-coding genes, 22 transfer RNA genes, and two ribosomal RNA genes. The GC content of this mitochondrial genome is 45.96% (27.47% A, 26.57%T, 30.12% C, and 15.84% G), similar to Astatotilapia calliptera (the GC content of 45.90%). We constructed a phylogenetic tree on the complete mitochondrial genomes of these two species and other 10 closely related species to show their phylogenic relationship. The complete mitochondrial genome of F. rostratus and its phylogenic relationship with other related species would facilitate our understanding of the evolution of Cichlidae mitochondrial genome.


Assuntos
Ciclídeos/genética , DNA Mitocondrial/genética , Genoma Mitocondrial/genética , Animais , Composição de Bases/genética , Sequência de Bases/genética , Sequência Conservada/genética , Ordem dos Genes/genética , Genes Mitocondriais/genética , Genoma , Filogenia , Análise de Sequência de DNA/métodos
7.
Sci Total Environ ; 572: 1244-1251, 2016 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-26412422

RESUMO

To better characterize the chemical compositions and sources of fine particulate matter (i.e. PM2.5) in Sanjiang Plain, Northeast China, total carbon (TC), organic carbon (OC), elemental carbon (EC), water-soluble organic carbon (WSOC), and inorganic ions as well as stable carbon isotopic composition (δ13C) were measured in this study. Intensively open biomass burning episodes are identified from late September to early October by satellite fire and aerosol optical depth maps. During the biomass-burning episode, concentrations of PM2.5, OC, EC, and WSOC are increased by a factor of 4-12 compared to those during the non-biomass-burning period. Non-sea-salt potassium is strongly correlated with PM2.5, OC, EC and WSOC, demonstrating an important contribution from biomass-burning emissions. The enrichment in both the non-sea-salt potassium and chlorine is significantly larger than other inorganic species, suggesting that biomass-burning aerosols in Sanjiang Plain are mostly fresh and less aged. In addition, the WSOC-to-OC ratio is lower than that reported in biomass-burning aerosols in tropical regions, further supporting that biomass-burning aerosols in Sanjiang Plain are mostly primary and secondary organic aerosols may be not significant. A lower average δ13C value (-26.2‰) is observed during the biomass-burning period, indicating a dominant contribution from combustion of C3 plants in the studied region.


Assuntos
Aerossóis/análise , Poluentes Atmosféricos/análise , Carbono/análise , Material Particulado/análise , Biomassa , Isótopos de Carbono/análise , China , Monitoramento Ambiental , Fogo
8.
Huan Jing Ke Xue ; 36(3): 969-79, 2015 Mar.
Artigo em Chinês | MEDLINE | ID: mdl-25929065

RESUMO

A mineral-based porous granulation material (MPGM) was prepared for absorbing the heavy metal ions from quartz processing wastewater. Analytic results of the MPGM were illustrated by the techniques of BET, SEM and FT-IR, which revealed the excellent properties of multi-aperture distribution, large specific surface area, low loss ratio and so on; the N2 adsorption-desorption isotherm was type-III with H4 hysteresis loop; the functional groups were dominated by groups of layer silicate mineral. A batch adsorption study was carried out with varied adsorbent dosage, initial pH and reaction time. The results showed that the residual ion concentrations of Fe, Zn, Mn and As were decreased from 77.760, 3.700, 2.789 and 0.963 mg x L(-1) to 3.421, 0.574, 0.126 and 0.034 mg x L(-1), respectively. MPGM might be re-utilized after desorption by 1.0 mol x L(-1) NaCl for 12 hours, and the ideal adsorption performance was maintained after 5 recyclings. The adsorption equilibrium and kinetics followed Langmuir and typical pseudo-first-order/pseudo-second-order adsorption models. Thermodynamic parameters of ΔG(θ) < 0, ΔHθ > 0, ΔSθ > 0 showed that the adsorptions were spontaneous and endothermic processes in the temperature range of 15-45 degrees C.


Assuntos
Águas Residuárias/química , Purificação da Água/métodos , Adsorção , Concentração de Íons de Hidrogênio , Minerais , Porosidade , Quartzo , Termodinâmica
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