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Search Results: 1 - 10 of 37235 matches for " Zhiping Zhao "
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地理科学进展 , 2008, DOI: 10.11820/dlkxjz.2008.03.004
Abstract: Undertheintegratedinfluencesofglobalclimatechangesandovergrazing,Chinarangelandhasdegradedoverrecentyears.MaduoCountylocatesintheSourceRegionofYellowRiveranditsrangelandhasexperiencedexpansivedegradation.ThegovernmentofQinghaiProvincelaunchedaneco-immigrationpolicyin2004.Inordertoanalyzetheresponsesofherdfamiliestotheeco-immigrationandthereasonsfortheseresponses,theauthorsusedthreeperiodsMSSandTMimagesforrecent25yearsandinterviewsurveydataof144herdfamiliesinrecenttwoyears,gettingthefollowingresults(1)therangelandhaddegradedextensivelyforrecent28years;and(2)theimmigrantfamiliesweremainlycomposedoftheold,withlittleornolivestock.What'smore,thepercentageofimmigranthouseholdsthatshareonerangelandcertificatewithparentsorbrothersintheimmigrantfamilywas54.5%.Therefore,itishardtogreatlydecreasetheovergrazingdegreethrougheco-immigrationwiththosepreviouscharacteristicsofeco-immigrantfamilystructure.
An Expectation Maximization Algorithm to Model Failure Times by Continuous-Time Markov Chains
Qihong Duan,Zhiping Chen,Dengfu Zhao
Mathematical Problems in Engineering , 2010, DOI: 10.1155/2010/242567
Abstract: In many applications, the failure rate function may present a bathtub shape curve. In this paper, an expectation maximization algorithm is proposed to construct a suitable continuous-time Markov chain which models the failure time data by the first time reaching the absorbing state. Assume that a system is described by methods of supplementary variables, the device of stage, and so on. Given a data set, the maximum likelihood estimators of the initial distribution and the infinitesimal transition rates of the Markov chain can be obtained by our novel algorithm. Suppose that there are transient states in the system and that there are failure time data. The devised algorithm only needs to compute the exponential of upper triangular matrices for times in each iteration. Finally, the algorithm is applied to two real data sets, which indicates the practicality and efficiency of our algorithm. 1. Introduction Among many quantitative analysis methods of system reliability, the state space representation has often been employed by reliability engineers, for example, [1–5]. The state space representation has been recognized by industrial IEC61511 standards [6]. This method assumes that the structure of the system is modelled with a continuous-time Markov chain (CTMC). In the state space representation, nodes represent states of the system and arcs represent the transitions between nodes. This method is well adapted to study the reliability of various systems and allows an exact analysis of their probability of failure. In the state space representation method, the time interval between two consecutive transitions is a random variable of an exponential distribution. However, many studies have presented counterexamples. For some mechanical and electronic components, the failure rate function of time to failure (TTF) has a bathtub curve: a monotonically decreasing function initially, eventually becoming a constant, and finally changing to a monotonically increasing function after sufficient time elapses [7]. Because existing approaches do not provide a perfect solution to deal with this class of systems, several researchers have explored models with nonexponential distributions (see [8–10] and references therein). Among many approaches treating TTF with nonexponential distributions, the extended Markov-model [11] is recommendable. In the extended Markov-model, an operation state is divided into substates with different levels of failure rates, which result in a nonconstant failure rate of the operation state. That is, in these models, the bug of failure rate
Spectral properties of LH2 exhibit very similar even when heterologously express LH2 with β-subunit fusion protein in Rhodobacter sphaeroides  [PDF]
Zhiping Zhao, Xin Nie, Zongli Hu, Guoping Chen, Zaixin Li, Zhi Zhang
Advances in Biological Chemistry (ABC) , 2013, DOI: 10.4236/abc.2013.31013

Interactions between the light-harvesting subunits and the non-covalently bound photopigments attribute considerably to the spectral properties of photosynthetic bacteria light-harvesting complexes. In our previous studies, we have constructed a novel Rhodobacter sphaeroides expression system. In the present study, we focus on the spectral properties of LH2 when heterologously express LH2 with β-subunit- GFP fusion protein in Rb. sphaeroides. Near infra-red spectrum of LH2 remained nearly unchanged as measured by spectroscopy. Fluorescence spectrum suggested that the LH2 with β-subunit-GFP fusion protein complexes still possessed normal activity in energy transfer. However, photopigments contents were significantly decreased to a very low level in the LH2 with β-subunit-GFP fusion protein complexes compared to that of LH2. FT-IR spectra indicated that interactions between photopigments and LH2 α/β- subunits appeared not to be changed. It was concluded that the LH2 spectral properties exhibited very similar even when heterologously expressed LH2 b-subunit fusion protein in Rb. sphaeroides. Our present study may supply a new insight into better understand the interactions between light-harvesting subunits and photopigments and bacterial photosynthesis and promote the development of the novel Rb. sphaeroides expression system.

Amino terminus mutant OmpA from an isolated antibiotic resistant Escherichia coli still possess resistance to environmental stresses  [PDF]
Zhiping Zhao, Xin Nie, Zaixin Li, Zhi Zhang, Jie Ding, Wanru Xie
Advances in Biological Chemistry (ABC) , 2013, DOI: 10.4236/abc.2013.31014

Antibiotic resistant Escherichia coli strains are becoming more common recently. OmpA is a very important antigen protein of E. coli, which consists of two separate domains, N-terminal and C-terminal domain. The N-terminal domain contains eight β- barrel regions that plays important roles in the multifaceted functions of OmpA. In the present study, we cloned a mutant OmpA gene from a multi-antibiotic resistant E. coli strain. Sequence analysis indicated that the N-terminal DNA sequence of the mutant OmpA shared 81.05% homology with the modeled OmpA from E. coli K12 and the N-terminal amino acid sequence of the mutant OmpA was 81.22% identical to that of the E. coli K12 OmpA. Moreover, several amino acids located in the β-barrel region were mutated. The mutant OmpA was expressed in BL21 suggested by SDS-PAGE. Resistance to environmental stress assay indicated that the N-terminus mutant OmpA still possessed excellent activities in pH, temperature and osmotic pressure resistance. Our pre- sent study may supply insights into better and deeper understand the relationships between OmpA N-terminal regions and its functions in environmental stress conditions and the mechanisms on antibiotic resistance of E. coli.


ZHAO Zhiping,

力学与实践 , 2007,
Abstract: The bending resistance function of a reinforced concrete beam is simulated by using ANSYS 10.0 software.The modeling of the reinforced concrete beam is three-dimensional.The simulation includes critical loads,deflection,stress distribution,movement of neutral axis and so on.The yield load and the ultimate load are found to agree with the actual loads.The method may be used to simulate the load capacity of RC beams (slabs).
Normality of Ethernet Traffic at Large Time Scales
Zhiping Lu,Ming Li,Wei Zhao
Mathematical Problems in Engineering , 2013, DOI: 10.1155/2013/471963
Viremia Associated with Fatal Outcomes in Ferrets Infected with Avian H5N1 Influenza Virus
Xue Wang,Jiangqin Zhao,Shixing Tang,Zhiping Ye,Indira Hewlett
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0012099
Abstract: Avian H5N1 influenza viruses cause severe disease and high mortality in infected humans. However, tissue tropism and underlying pathogenesis of H5N1 virus infection in humans needs further investigation. The objective of this work was to study viremia, tissue tropism and disease pathogenesis of H5N1 virus infection in the susceptible ferret animal model. To evaluate the relationship of morbidity and mortality with virus loads, we performed studies in ferrets infected with the H5N1 strain A/VN/1203/04 to assess clinical signs after infection and virus load in lung, brain, ileum, nasal turbinate, nasal wash, and blood. We observed that H5N1 infection in ferrets is characterized by high virus load in the brain and and low levels in the ileum using real-time PCR. In addition, viral RNA was frequently detected in blood one or two days before death and associated with symptoms of diarrhea. Our observations further substantiate pathogenicity of H5N1 and further indicate that viremia may be a bio-marker for fatal outcomes in H5N1 infection.
Stability and infectivity of novel pandemic influenza A (H1N1) virus in blood-derived matrices under different storage conditions
Xue Wang, Olga Zoueva, Jiangqin Zhao, Zhiping Ye, Indira Hewlett
BMC Infectious Diseases , 2011, DOI: 10.1186/1471-2334-11-354
Abstract: We examined the stability of novel pandemic influenza A (H1N1) virus RNA when the virus was stored in phosphate buffered saline (PBS), plasma, or buffy coated blood at either room temperature or 4°C using a sensitive Taqman RT-PCR assay. We also investigated virus infectivity using the EID50 assay when virus was stored in PBS, plasma, or buffy coats isolated from blood at 4°C.Viral RNA stability was affected by the matrix used for storage. The recovery of viral RNA was highest when virus was stored in PBS with lower amounts being recovered from plasma and buffy coats at either room temperature or 4°C. Incubation time did not appear to be a major factor for viral RNA stability, although there was gradual decline after longer periods post-incubation. Both sample matrix and incubation time affected virus infectivity. The decay in virus infectivity was greatest in PBS followed by buffy coats and plasma. Virus infectivity was abolished in buffy coats at day 20 post-incubation when virus concentrations were low.These data indicate that encapsidated viral RNA was stable overall in all three liquid matrices at room temperature or 4°C although it was most stable in PBS; virus infectivity in buffy coats at 4°C decayed in a time dependent manner while it remained unchanged in plasma. These findings have implications for storage, handling and transport of blood derived samples from influenza patients for epidemiological and laboratory investigations. It should be noted that there is little known about influenza viremia, and whether influenza viruses can be transmitted by blood or blood derived samples.Influenza is a major cause of morbidity and mortality in the United States and worldwide. The possibility of an influenza pandemic has focused attention on the epidemiology and pathophysiology of influenza, including its potential for viremia in the acute phase of infection [1].Influenza A viruses belong to the Orthomyxoviridae family of RNA viruses. They contain eight segments of
Eco-immigration Policy for the Degraded Rangeland and Responses of Herd Family in the Source Region of Yellow River——Case Study Based on Household Investigation in Maduo County
Eco- immigr ation Policy for the Degr aded Rangeland and Responses of Herd Family in the Sour ce Region of Yellow River——Case Study Based on Household Investigation in Maduo County

LU Qingshui,ZHAO Zhiping,

地理科学进展 , 2008,
Abstract: Under the integrated influences of global climate changes and overgrazing, China rangeland has degraded over recent years. Maduo County locates in the Source Region of Yellow River and its rangeland has experienced expansive degradation. The government of Qinghai Province launched an eco-immigration policy in 2004. In order to analyze the responses of herd families to the eco-immigration and the reasons for these responses, the authors used three periods MSS and TM images for recent 25 years and interview survey data of 144 herd families in recent two years, getting the following results: (1) the rangeland had degraded extensively for recent 28 years; and (2) the immigrant families were mainly composed of the old, with little or no livestock. What's more, the percentage of immigrant households that share one rangeland certificate with parents or brothers in the immigrant family was 54.5%. Therefore, it is hard to greatly decrease the overgrazing degree through eco-immigration with those previous characteristics of eco-immigrant family structure.
Leachate treatment using a demonstration aged refuse biofilter

Hongjiang Li,Yingying Gu,Youcai Zhao,Zhiping Wen,

环境科学学报(英文版) , 2010,
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