Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 4 de 4
Filtrar
Mais filtros








Base de dados
Intervalo de ano de publicação
1.
Huan Jing Ke Xue ; 45(2): 645-654, 2024 Feb 08.
Artigo em Chinês | MEDLINE | ID: mdl-38471905

RESUMO

It is of great importance to scientifically evaluate the impact of weather and climate conditions on the occurrence of O3 pollution in order to improve the accuracy of O3 pollution forecasts, as well as to reasonably control and reduce the adverse effects of O3 pollution. The characteristics of O3 concentration and climate background were analyzed based on daily O3 concentration data, meteorological factors, and NCEP/NCER reanalysis data from 2006 to 2021 in Shanghai. In addition, the differences in atmospheric circulation situations during years with anomalous O3 concentrations were compared and diagnosed from the perspective of climatology. Additionally, the monthly O3 concentration prediction model (seasonal autoregressive integrated moving average with exogenous regressors, SARIMAX) was further established by adding the key meteorological factors. The results indicated that both the whole-year average and summer half-year average O3 concentrations in Shanghai were increasing with fluctuation, and the summer half-year average was much higher than the annual average, up to 36.2%. Furthermore, there was a significant negative correlation between O3 concentration and wind speed (correlation coefficient of -0.826) and a significant positive correlation with the frequency of static wind and the number of days in which the low cloud cover was less than 20% (correlation coefficients of 0.836 and 0.724, respectively). The monthly mean O3 concentration had a clear periodicity, showing a pattern with a high concentration in the middle period (April to September) and a low concentration at the beginning and end of the periods. High O3 concentration years (2013-2021) were accompanied by more polluted days, lower average wind speed, more small wind (≤1.5 m·s-1) days, more days of low cloud cover of less than 20%, more days of high temperature, higher direct solar radiation, and more sunshine hours. When the location of the stronger West Pacific subtropical high was westward and southward in the summer half-year, Shanghai was influenced by an anomalous westerly wind, which was not conducive to the transportation of clean air from the sea to Shanghai and thus led to the high concentration of O3 pollution. When the long wave radiation emitted from the ground was low in the summer half-year, it was favorable for the increase in ground temperature and caused a high concentration of O3 pollution. Adding direct solar radiation, maximum temperature, and wind speed as exogenous variables to the monthly O3 forecast model could significantly improve the effectiveness of the monthly forecast, with the root mean square error decreasing by 47.7% (from 22 to 11.5) and the correlation coefficient increasing by 11.2% (from 0.819 to 0.911), which could be applied to the practical prediction of monthly O3 concentration.

2.
Huan Jing Ke Xue ; 41(1): 14-22, 2020 Jan 08.
Artigo em Chinês | MEDLINE | ID: mdl-31854899

RESUMO

We use daily aerosol particulate matter<10 µm (PM10) concentration data from 2006 to 2016 in Shanghai along with meteorological elements (wind and temperature), atmospheric stability, temperature inversion, and upper atmosphere circulation data, to analyze the variation characteristics of the PM10 concentrations and differences of the winter climate background. We establish a multivariate linear stepwise regression equation, and also compare and analyze differences in the upper atmospheric circulation by selecting the years with the highest and lowest PM10 concentrations. The results showed an oscillating downward trend in the annual average concentrations of PM10 in Shanghai, whereas seasonally, PM10 concentrations were relatively high in winter and showed two peaks with a low in between. PM10 concentrations were negatively correlated with the daily average wind speed and the daily mixing layer height at 20:00, and positively correlated with the frequency of northwest wind, the mean daily temperature, and the frequency of stable weathers and thermal inversion at 20:00. When the 500 hPa height field in the northern part of China was a positive anomaly in winter, a warm winter prevailed and led to high PM10 concentrations. When the 500 hPa height field was a negative anomaly, cold air frequently moved southward to result in relatively low temperatures, which caused relatively low PM10 concentrations. When the wind field at 850 hPa was easterly, the wind speed was relatively large and resulted in relatively low PM10 concentrations.

3.
Zhonghua Er Ke Za Zhi ; 45(9): 703-7, 2007 Sep.
Artigo em Chinês | MEDLINE | ID: mdl-18021567

RESUMO

OBJECTIVE: To investigative vacA, cagA and iceA genes dominant genotypes of Helicobacter pylori (Hp) isolated from children suffering from gastric and duodenal diseases in Guangzhou area. METHODS: Totally 105 children who underwent gastroscopy in Guangzhou Children's Hospital were enrolled into this study. From each patient, 3 biopsy specimens from the gastric antrum were taken, one was used for rapid urease test, one for histological examination, and one for polymerase chain reaction (PCR) for detecting ureA, vacA, cagA, and iceA genes. DNA was prepared directly from the biopsy specimens from the gastric antrum using a QIAamp DNA mini kit (Qiagen, Germany) according to the manufacturer's instructions. Then 11 primers were used for detecting the genotypes including ureas, (s1, s1a, s1b, s1c, s2) and m (m1, m1T, m2) region of vacA, cagA and iceA (iceA1 and iceA2) genotypes in the 105 children. The distribution of the genotypes of Hp was analyzed. RESULT: Among the 105 children, only 52 children were positive by the three methods, among these 52 children, 26 were boys and 26 girls. Hp vacA s1as1c/m2 was detected in 43 out of 52 children (82.7%), s1as1c/m1T in 9.6% (5/52), m region that could not betyped was 7.7% (4/52). No strains presented genotypes vacA s1b, s2, m1. The comparison of the positive ratio of vacA s1as1 c/m2 detected in the children infected with Hp and that of the other combination of signal region and middle region was statistically significantly different (P < 0.01). With regard to cagA gene, cagA(+) gene and cagA(-) gene were found in 90.4% (47/52) and 9.6% (5/52) of the children, respectively. The cagA(+) gene was more frequent in the children infected with Hp. Single iceA1 was detected in 78.8% (41/52) children, and single iceA2 was detected to be 1.9% (1/52), multiple strains infection of iceA1 and iceA2 were detected in 3.8% (2/52) children, iceA1 and iceA2 were not detected in 15.4% (8/52), the comparison of the positive ratio of iceA1 detected in the children infected with Hp and that of the other genotypes was statistically significantly different (P < 0.01). CONCLUSION: The s1as1c/m2, cagA and iceA1 were the dominant genotypes of Hp in the children in Guangzhou area and s1as1c/m2, cagA and iceA1 were the dominant genotypes combination of Hp in the children in this area.


Assuntos
Genes Bacterianos/genética , Genótipo , Infecções por Helicobacter/genética , Helicobacter pylori/genética , Antro Pilórico/microbiologia , Antígenos de Bactérias/genética , Antígenos de Bactérias/uso terapêutico , Proteínas da Membrana Bacteriana Externa/genética , Proteínas de Bactérias/genética , Criança , China/epidemiologia , Feminino , Genes Bacterianos/efeitos dos fármacos , Infecções por Helicobacter/tratamento farmacológico , Humanos , Masculino , Reação em Cadeia da Polimerase
4.
Yi Chuan ; 28(2): 200-7, 2006 Feb.
Artigo em Chinês | MEDLINE | ID: mdl-16520317

RESUMO

The completed genome sequence of filamental fungus Neurospora crassa has completed and 10,082 open reading frames (ORFs) were predicted in whole genome. Among them, 437 proteins were secreted ones based on the combination of prediction algorithms SignalP v3.0 and PSORT, transmembrane domains prediction algorithms TMHMM v2.0 and THUMBUP, potential GPI-anchor sites prediction algorithm big-PI predictor and the subcellular protein location prediction algorithm TargetP v1.01. The minimum ORF length of the encoding sequences for 437 secreted proteins was 252 bp, the maximum ORF length was 6 604 bp and average was 1 433 bp. The length of signal peptide of secreted proteins ranged from 15 to 59 amino acids. Among the 437 secreted proteins, 205 were provided with function description. The function of secretory proteins were involved in kinds of enzyme, cell energy, transmission, cell recovered itself and defense mechanism et al. These results implied that processes catalyzed by these proteins probably occurred outside of cells, at least partially.


Assuntos
Proteínas Fúngicas/genética , Genoma Fúngico/genética , Neurospora crassa/genética , Neurospora crassa/metabolismo , Sequência de Aminoácidos , Proteínas Fúngicas/química , Sinais Direcionadores de Proteínas/genética
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA