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Search Results: 1 - 10 of 22922 matches for " ZhenGan Yuan "
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Detennination of trace uranium in environment by laser induced fluorescence method
Wu Jinhai,Yuan Zhengan,Li Jinquan,Zhang Chuanzuo,Ren Lihua,
Wu Jinhai
,Yuan Zhengan,Li Jinquan,Zhang Chuanzuo,Ren Lihua

环境科学学报(英文版) , 1994,
Abstract: he analytical technique of trace uranium has been developed rapidly since Robbins firstreported the laser uranium analyzer in 1978. Because of the complicated operation and experimentalprocedure of the normal spectrophotometer, neutron activation and solid fluorescence, they havebeen replaced gradually by the laser induced fluoresccncc mcthod. According to high sensitivity andIow detection limit of the fluoreseenee, it can determine the trace uranium. The uranium content inthe lake water, underground water and rain etc. can be measured directly without pretreatment. Therange of the method for determining uranium is from 005 ppb to 20 ppb, and the detection limitis 0.05 ppb.
High Prevalence of Human Parvovirus 4 Infection in HBV and HCV Infected Individuals in Shanghai
Xuelian Yu, Jing Zhang, Liang Hong, Jiayu Wang, Zhengan Yuan, Xi Zhang, Reena Ghildyal
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0029474
Abstract: Human parvovirus 4 (PARV4) has been detected in blood and diverse tissues samples from HIV/AIDS patients who are injecting drug users. Although B19 virus, the best characterized human parvovirus, has been shown to co-infect patients with hepatitis B or hepatitis C virus (HBV, HCV) infection, the association of PARV4 with HBV or HCV infections is still unknown. The aim of this study was to characterise the association of viruses belonging to PARV4 genotype 1 and 2 with chronic HBV and HCV infection in Shanghai. Serum samples of healthy controls, HCV infected subjects and HBV infected subjects were retrieved from Shanghai Center for Disease Control and Prevention (SCDC) Sample Bank. Parvovirus-specific nested-PCR was performed and results confirmed by sequencing. Sequences were compared with reference sequences obtained from Genbank to derive phylogeny trees. The frequency of parvovirus molecular detection was 16–22%, 33% and 41% in healthy controls, HCV infected and HBV infected subjects respectively, with PARV4 being the only parvovirus detected. HCV infected and HBV infected subjects had a significantly higher PARV4 prevalence than the healthy population. No statistical difference was found in PARV4 prevalence between HBV or HCV infected subjects. PARV4 sequence divergence within study groups was similar in healthy subjects, HBV or HCV infected subjects. Our data clearly demonstrate that PARV4 infection is strongly associated with HCV and HBV infection in Shanghai but may not cause increased disease severity.
Applied Mixed Generalized Additive Model to Assess the Effect of Temperature on the Incidence of Bacillary Dysentery and Its Forecast
Weiping Ma, Xiaodong Sun, Yanyan Song, Fangfang Tao, Wei Feng, Yi He, Naiqing Zhao, Zhengan Yuan
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0062122
Abstract: Background Association between bacillary dysentery (BD) disease and temperature has been reported in some studies applying Poisson regression model, however the effect estimation might be biased due to the data autocorrelation. Furthermore the temperature effect distributed in the time of different lags has not been studied either. The purpose of this work was to obtaining the association between the BD counts and the climatic factors such as temperature in the form of the weighted averages, concerning the autocorrelation pattern of the model residuals, and to make short term predictions using the model. The data was collected in the city of Shanghai from 2004 to 2008. Methods We used mixed generalized additive model (MGAM) to analyze data on bacillary dysentery, temperature and other covariates with autoregressive random effect. Short term predictions were made using MGAM with the moving average of the BD counts. Main Results Our results showed that temperature was significant linearly associated with the logarithm of BD count for temperature in the range from 12°C to 22°C. Optimal weights in the temperature effect have been obtained, in which the one of 1-day-lag was close to 0, and the one of 2-days-lag was the maximum (p-value of the difference was less than 0.05). The predictive model was showing good fitness on the internal data with R2 value 0.875, and the good short term prediction effect on the external data with correlation coefficient to be 0.859. Conclusion According to the model estimation, corresponding Risk Ratio to affect BD was close to 1.1 when temperature effect goes up for 1°C in the range from 12°C to 22°C. And the 1-day incubation period could be inferred from the model estimation. Good prediction has been made using the predictive MGAM.
Positive solutions for a class of singular boundary-value problems
Li Xia,Zhengan Yao
Electronic Journal of Differential Equations , 2007,
Abstract: Using regularization and the sub-super solutions method, this note shows the existence of positive solutions for singular differential equation subject to four-point boundary conditions.
Intensive Cytokine induction in Pandemic H1N1 Influenza Virus Infection Accompanied by Robust Production of IL-10 and IL-6
Xuelian Yu,Xi Zhang,Baihui Zhao,Jiayu Wang,Zhaokui Zhu,Zheng Teng,Junjie Shao,Jiaren Shen,Ye Gao,Zhengan Yuan,Fan Wu
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0028680
Abstract: The innate immune system is the first line of defense against viruses by inducing expression of cytokines and chemokines. Many pandemic influenza H1N1 virus [P(H1N1)] infected severe cases occur in young adults under 18 years old who were rarely seriously affected by seasonal influenza. Results regarding host cytokine profiles of P(H1N1) are ambivalent. In the present study we investigated host cytokine profiles in P(H1N1) patients and identified cytokines related to disease severity.
High Human Bocavirus Viral Load Is Associated with Disease Severity in Children under Five Years of Age
Baihui Zhao, Xuelian Yu, Chuanxian Wang, Zheng Teng, Chun Wang, Jiaren Shen, Ye Gao, Zhaokui Zhu, Jiayu Wang, Zhengan Yuan, Fan Wu, Xi Zhang, Reena Ghildyal
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0062318
Abstract: Human bocavirus (HBoV) is a parvovirus and detected worldwide in lower respiratory tract infections (LRTIs), but its pathogenic role in respiratory illness is still debatable due to high incidence of co-infection with other respiratory viruses. To determine the prevalence of HBoV infection in patients with LRTI in Shanghai and its correlation with disease severity, we performed a 3-year prospective study of HBoV in healthy controls, outpatients and inpatients under five years of age with X-ray diagnosed LRTIs. Nasopharyngeal aspirates were tested by PCR for common respiratory viruses and by real time PCR for HBoV subtypes 1–4. Nasopharyngeal swabs from healthy controls and serum samples and stools from inpatients were also tested for HBoV1-4 by real time PCR. Viral loads were determined by quantitative real time PCR in all HBoV positive samples. HBoV1 was detected in 7.0% of inpatients, with annual rates of 5.1%, 8.0% and 4.8% in 2010, 2011 and 2012, respectively. Respiratory syncytial virus (RSV) subtype A was the most frequent co-infection detected; HBoV1 and RSVA appeared to co-circulate with similar seasonal variations. High HBoV viral loads (>106 copies/ml) were significantly more frequent in inpatients and outpatients than in healthy controls. There was a direct correlation of high viral load with increasing disease severity in patients co-infected with HBoV1 and at least one other respiratory virus. In summary, our data suggest that HBoV1 can cause LRTIs, but symptomatic HBoV infection is only observed in the context of high viral load.
Solutions of fourth-order partial differential equations in a noise removal model
Qiang Liu,Zhengan Yao,Yuanyuan Ke
Electronic Journal of Differential Equations , 2007,
Abstract: In this paper, we discuss the existence and uniqueness of weak solutions for a fourth-order partial differential equation stemmed from image processing for noise removal. We also present some numerical tests for high order filters.
Dynamics of Soil Organic Carbon and Microbial Biomass Carbon in Relation to Water Erosion and Tillage Erosion
Nie Xiaojun, Zhang Jianhui, Su Zhengan
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0064059
Abstract: Dynamics of soil organic carbon (SOC) are associated with soil erosion, yet there is a shortage of research concerning the relationship between soil erosion, SOC, and especially microbial biomass carbon (MBC). In this paper, we selected two typical slope landscapes including gentle and steep slopes from the Sichuan Basin, China, and used the 137Cs technique to determine the effects of water erosion and tillage erosion on the dynamics of SOC and MBC. Soil samples for the determination of 137Cs, SOC, MBC and soil particle-size fractions were collected on two types of contrasting hillslopes. 137Cs data revealed that soil loss occurred at upper slope positions of the two landscapes and soil accumulation at the lower slope positions. Soil erosion rates as well as distribution patterns of the <0.002-mm clay shows that water erosion is the major process of soil redistribution in the gentle slope landscape, while tillage erosion acts as the dominant process of soil redistribution in the steep slope landscape. In gentle slope landscapes, both SOC and MBC contents increased downslope and these distribution patterns were closely linked to soil redistribution rates. In steep slope landscapes, only SOC contents increased downslope, dependent on soil redistribution. It is noticeable that MBC/SOC ratios were significantly lower in gentle slope landscapes than in steep slope landscapes, implying that water erosion has a negative effect on the microbial biomass compared with tillage erosion. It is suggested that MBC dynamics are closely associated with soil redistribution by water erosion but independent of that by tillage erosion, while SOC dynamics are influenced by soil redistribution by both water erosion and tillage erosion.
Regularity criteria for the 3D MHD equations in term of velocity
Qunyi Bie,Qiru Wang,Zhengan Yao
Mathematics , 2013,
Abstract: In this paper we consider three-dimensional incompressible magnetohydrodynamics equations. By using interpolation inequalities in anisotropic Lebesgue space, we provide regularity criteria involving the velocity or alternatively involving the fractional derivative of velocity in one direction, which generalize some known results.
Domain Oscillation Criteria for a Forced Second Order Elliptic Differential Equations

Zhuang Rongkun,Yao Zhengan,

数学物理学报(A辑) , 2007,
Abstract: 对二阶非线性椭圆型方程建立了若干新的振动准则,所得结果仅依赖于方程在外区域Ω■R"的一个子区域序列的信息而有别于已知的大多数结论.
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