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Search Results: 1 - 10 of 78308 matches for " Xueli Chen "
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Numerical Study of Initial Soil Moisture Impacts on Regional Surface Climate  [PDF]
Xueli Shi
Atmospheric and Climate Sciences (ACS) , 2011, DOI: 10.4236/acs.2011.14019
Abstract: In this paper, the impacts of initial soil moisture (SM) over the Huaihe River Basin of China on the summertime climate have been investigated with a regional climate model. Three fourth-month-long simulations are made for two summers, the abnormal flooding in 2003 and normal climate in 2004. Besides control simulations (noted as CTL), sensitivity experiments have been conducted by assigning the initial soil moisture equals to 50% and 150% of the simulated soil moisture while keeping the others unchanged, which are noted as SM50 and SM150, respectively.The results show that effects of initial SM anomalies at late spring can last for the whole summer, and the increase of initial soil moisture (SM150) has more significant effects than the decreased one (SM50). The differences between sensitivity experiments and CTL mainly appear at surface and near-surface atmosphere. When increasing the initial SM, the latent heat flux and surface soil moisture are increased, correspondingly the sensible heat flux, temperature and radiation are all decreased. The changes of rainfall are not distinct between SM50 and SM150, which might be related to the processes within atmosphere, especially the humidity pattern.
An accurate solution of point kinetics equations of one-group delayed neutrons and an extraneous neutron source for step reactivity insertion
HaoFeng Li,XueLi Shang,WenZhen Chen
Chinese Science Bulletin , 2010, DOI: 10.1007/s11434-010-4220-2
Abstract: The continuous indication of the neutron density and its rate of change are important for the safe startup and operation of reactors. The best way to achieve this is to obtain analytical solutions of the neutron kinetics equations because none of the developed numerical methods can well satisfy the need for real-time or even super-time computation for the safe startup and operation of reactors in practice. In this paper, an accurate analytical solution of point kinetics equations with one-group delayed neutrons and an extraneous neutron source is proposed to calculate the change in neutron density, where the whole process from the subcritical stage to critical and supercritical stages is considered for step reactivity insertions. The accurate analytical solution can also be used as a benchmark of all numerical methods employed to solve stiff neutron kinetics equations.
Risk Factors for Gastrointestinal Injuries in Acute Coronary Syndrome Patients with Double Antiplatelet Therapy in One-Year Follow-Up  [PDF]
Ling Zhong, Xin Chen, Xihua Qiu, Xueli Zhang, Hua Shao, Yamin Liu, Jing Xiong
World Journal of Cardiovascular Diseases (WJCD) , 2018, DOI: 10.4236/wjcd.2018.810046
Abstract: Background: The goal is to determine the incidence of symptomatic gastrointestinal (GI) injuries in acute coronary syndrome (ACS) patients receiving double antiplatelet therapy (DAPT). The risk factors for serious GI complications are also evaluated. Methods: 603 eligible patients from the Department of Cardiology at Zhongda Hospital between January 2014 and August 2015 were enrolled and the occurrence of GI injuries within one year assessed. The risk factors for serious GI complications were identified using cox regression analysis. Results: After one-year follow-up, 108 (17.9%) out of 603 patients developed symptomatic GI injuries: 22 (3.65%) with serious GI complications and 86 (14.2%) with GI symptoms. Drinking habit (95% CI: 1.512 - 8.796; P = 0.004) and previous peptic injury (95% CI: 2.307 - 18.080; P = 0.001) are independent predictors of serious GI complications, while proton pump inhibitor (PPI) was protective (95% CI: 0.120 - 0.699; P = 0.006) per cox regression analysis. Additionally, GI injuries of both serious GI complications and GI symptoms peaked in the first three months. Conclusions: Symptomatic GI injuries were relatively
Review of the Domestic Crowdfunding Industry Development  [PDF]
Defeng Yang, Xueli Zhang
Journal of Service Science and Management (JSSM) , 2016, DOI: 10.4236/jssm.2016.91006
Abstract: 2014 was called “the first year of the crowdfunding in China”. The State Council executive meeting on Nov. 19, 2014 put forward that we must establish a rapid refinance mechanism for capital markets, trying to launch equity crowdfunding. In December, the Securities Association of China solicited opinions on management measures of the private equity crowdfunding, which boosted the crowdfunding into the “fast track”. A lot of crowdfunding platforms appeared including the three giants (Jingdong, Taobao, Suning). The three giants occupied most of the market share. Other platforms constantly followed. Domestic crowdfunding industry has entered the flourishing mode. This paper analyzes the domestic developments of various crowdfunding platforms.
Labor-Leisure Choice: Is Everything as Straightforward as One Might Have Thought?  [PDF]
Emin Gahramanov, Xueli Tang
Theoretical Economics Letters (TEL) , 2016, DOI: 10.4236/tel.2016.64079
Abstract: We argue that a full understanding of a rational labor supply choice in a standard dynamic life cycle framework is obscure, despite the framework’s being seemingly self-explanatory, straight-forward, and intuitively sensible. In a completely friction-free environment, we, to our knowledge, are the first to provide a complete analytic solution to the benchmark model that presumes a kind of labor supply behavior that is typically taken as the standard in economic studies. We find that such standard behavior holds only for a narrow set of parameters. For many alternative parameterizations, the labor supply behavior of a rational agent is either highly unrealistic, or extremely hard to predict and interpret. A complete understanding of a rational, intertemporal labor supply choice requires further analysis.
The Annealed Entropy of Wiener Number on Random Double Hexagonal Chains  [PDF]
Haizhen Ren, Xueli Su
Applied Mathematics (AM) , 2017, DOI: 10.4236/am.2017.810108
Abstract:
We study a random planar honeycomb lattice model, namely the random double hexagonal chains. This is a lattice system with nonperiodic boundary condition. The Wiener number is an important molecular descriptor based on the distances, which was introduced by the chemist Harold Wiener in 1947. By applying probabilistic method and combinatorial techniques we obtained an explicit analytical expression for the expected value of Wiener number of a random double hexagonal chain, and the limiting behaviors on the annealed entropy of Wiener number when the random double hexagonal chain becomes infinite in length are analyzed.
Modulation of the Ribonucleotide Reductase-Antimetabolite Drug Interaction in Cancer Cell Lines
Jun Zhou,Paula Oliveira,Xueli Li,Zhengming Chen,Gerold Bepler
Journal of Nucleic Acids , 2010, DOI: 10.4061/2010/597098
Abstract: RRM1 is a determinant of gemcitabine efficacy in cancer patients. However, the precision of predicting tumor response based on RRM1 levels is not optimal. We used gene-specific overexpression and RNA interference to assess RRM1's impact on different classes of cytotoxic agents, on drug-drug interactions, and the modulating impact of other molecular and cellular parameters. RRM1 was the dominant determinant of gemcitabine efficacy in various cancer cell lines. RRM1 also impacted the efficacy of other antimetabolite agents. It did not disrupt the interaction of two cytotoxic agents when combined. Cell lines with truncation, deletion, and null status of p53 were resistant to gemcitabine without apparent relationship to RRM1 levels. Pemetrexed and carboplatin sensitivity did not appear to be related to p53 mutation status. The impact of p53 mutations in patients treated with gemcitabine should be studied in prospective clinical trials to develop a model with improved precision of predicting drug efficacy. 1. Introduction The regulatory subunit of ribonucleotide reductase (RRM1) has been identified as the key molecular determinant of gemcitabine efficacy both in vitro and in vivo [1–7]. Human lung and pancreatic cancer cell lines and a serially transplanted mouse colon cancer made resistant to gemcitabine through continuous exposure to increasing amounts of drug overexpressed RRM1 [1, 3, 5]. RRM1 overexpression through transfection of a lung cancer cell line likewise resulted in gemcitabine resistance [4]. Reduction of RRM1 expression through RNA interference abrogated the induced gemcitabine resistance and increased drug sensitivity in otherwise sensitive cell lines [4, 5]. An association between intratumoral RRM1 levels and efficacy of systemic therapy that includes gemcitabine as a single-agent or in combination with a platinum-agent or pemetrexed has also been reported [8]. However, the addition of a vinca-alkaloid (vinorelbine) to a gemcitabine-containing combination in patients with nonsmallcell lung cancer (NSCLC) appeared to abrogate the RRM1-gemcitabine efficacy association [2]. Although gemcitabine therapy is statistically significantly more efficacious in patients with low tumoral RRM1 levels, the scatter plots reported and correlation coefficients are less than optimal for precise predictions on whether or not gemcitabine will result in tumor shrinkage in individual patients [7]. Here we studied associations between RRM1 expression levels and sensitivities to frequently used chemotherapeutic single agents and combinations as well as cell lines
RNA interference as a gene silencing therapy for mutant MYOC protein in primary open angle glaucoma
Mao Li, Jianjiang Xu, Xueli Chen, Xinghuai Sun
Diagnostic Pathology , 2009, DOI: 10.1186/1746-1596-4-46
Abstract: We speculate that a complete elimination of mutant myocilin expression in trabecular meshwork cells is safe and that gives the possibility of avoiding the POAG phenotype.We propose RNA interference (RNAi) as a gene silencing therapy to eliminate the mutant myocilin proteins in the trabecular meshwork cells, either in a mutation-dependent or mutation-independent way due to the different engineering of the small interfering (si) RNA.The RNAi strategy can reverse the pathological process of trabecular meshwork cells and thus treat the POAG caused by myocilin gene mutation. This strategy can also be applicable to many protein-misfolding diseases caused by gain-of-function mutant proteins.Glaucoma is a group of progressive optic neuropathies that have in common a slow progressive degeneration of retinal ganglion cells and their axons, resulting in a distinct appearance of the optic disc and a concomitant pattern of visual loss[1]. Without adequate treatment, glaucoma can progress to irreversible visual disability and eventual blindness [1]. Of the many types of glaucoma, primary open angle glaucoma (POAG) is perhaps the most common, particularly in populations of African ancestry and European [2-4]. In most cases of POAG, increased resistance to the outflow of aqueous humor results in a rise in intraocular pressure (IOP), which eventually leads to loss of retinal ganglion cells[5]. Though Increased IOP has been proven to be the only treatable risk factor for glaucoma, the biological basis of the disease is not yet fully understood[1]. This may underlies that the present treatment of POAG directed at lowering IOP[6] does not seem to halt all cases of progression [7-10]. To date, six loci (GLC1A-E) have been linked to POAG alone. Among them, the gene MYOC encoding myocilin has been identified as harboring causal mutations, which are responsible for 3-4% adult-onset POAG cases [11]. This warrants the gene therapy which holds the promise for curing the disease. Current inves
Klotho inhibits growth and promotes apoptosis in human lung cancer cell line A549
Bo Chen, Xueli Wang, Weihong Zhao, Jianqing Wu
Journal of Experimental & Clinical Cancer Research , 2010, DOI: 10.1186/1756-9966-29-99
Abstract: In this study, plasmids encoding klotho or klotho specific shRNAs were constructed to overexpress or knockdown klotho in vitro. A549 cells were respectively treated with pCMV6-MYC-KL or klotho specific shRNAs. The MTT assay was used to evaluate the cytotoxic effects of klotho and flow cytometry was utilized to observe and detect the apoptosis of A549 cells induced by klotho. The activation of IGF-1/insulin signal pathways in A549 cells treated by pCMV6-MYC-KL or shRNAs were evaluated by western blotting. The expression levels of bcl-2 and bax transcripts were evaluated by quantitative reverse transcription-polymerase chain reaction (qRT-PCR).Overexpression of klotho reduced the proliferation of lung cancer A549 cells, whereas klotho silencing in A549 cells enhanced proliferation. Klotho did not show any effects on HEK-293 cells. Klotho overexpression in A549 cells was associated with reduced IGF-1/insulin-induced phosphorylation of IGF-1R (IGF-1 receptor)/IR (insulin receptor) (P < 0.01). Overexpression of klotho can promote the apoptosis of A549 cells (P < 0.01). Overexpression of klotho, a bcl family gene bax, was found up-regulated and bcl-2, an anti-apoptosis gene, was found down-regulated (P < 0.01). In contrast, bax and bcl-2 were found down-regulated (P < 0.05) and up-regulated (P < 0.01), respectively when silencing klotho using shRNAs.Klotho can inhibit proliferation and increase apoptosis of A549 cells, this may be partly due to the inhibition of IGF-1/insulin pathways and involving regulating the expression of the apoptosis-related genes bax/bcl-2. Thus, klotho can serve as a potential tumor suppressor in A549 cells.Aging is the greatest risk factor for cancer. About 77% of all cancers are diagnosed in people over 55 years old, with men facing a 50% chance of developing cancer, whereas women having a 35% chance. Thus, with the aging population increasing, it is expected that cancer will become an enormous challenge. Lung cancer is the leading cause of can
A computational model for functional mapping of genes that regulate intra-cellular circadian rhythms
Tian Liu, Xueli Liu, Yunmei Chen, Rongling Wu
Theoretical Biology and Medical Modelling , 2007, DOI: 10.1186/1742-4682-4-5
Abstract: We present a statistical model for mapping and characterizing specific genes or quantitative trait loci (QTL) that affect variations in rhythmic responses. This model integrates a system of differential equations into the framework for functional mapping, allowing hypotheses about the interplay between genetic actions and periodic rhythms to be tested. A simulation approach based on sustained circadian oscillations of the clock proteins and their mRNAs has been designed to test the statistical properties of the model.The model has significant implications for probing the molecular genetic mechanism of rhythmic oscillations through the detection of the clock QTL throughout the genome.Rhythmic phenomena are considered to involve a mechanism, ubiquitous among organisms populating the earth, for responding to daily and seasonal changes resulting from the planet's rotation and its orbit around the sun [1]. All these periodic responses are recorded in a circadian clock that allows the organism to anticipate rhythmic changes in the environment, thus equipping it with regulatory and adaptive machinery [2]. It is well recognized that circadian rhythms operate at all levels of biological organization, approximating a twenty-four hour period, or more accurately, the alternation between day and night [3]. Although there is a widely accepted view that the normal functions of biological processes are strongly correlated with the genes that control them, the detailed genetic mechanisms by which circadian behavior is generated and mediated are poorly understood [4].Several studies have identified various so-called circadian clock genes and clock-controlled transcription factors through mutants in animal models [5,6]. These genes have implications for clinical trials: their identification holds great promise for determining optimal times for drug administration based on an individual patient's genetic makeup. It has been suggested that drug administration at the appropriate body tim
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