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Search Results: 1 - 10 of 10575 matches for " Yadong Long "
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Variable Separation and Exact Solutions for the Kadomtsev-Petviashvili Equation  [PDF]
Lili Song, Yadong Shang
Advances in Pure Mathematics (APM) , 2015, DOI: 10.4236/apm.2015.53014
Abstract: In the paper, we will discuss the Kadomtsev-Petviashvili Equation which is used to model shallow-water waves with weakly non-linear restoring forces and is also used to model waves in ferromagnetic media by employing the method of variable separation. Abundant exact solutions including global smooth solutions and local blow up solutions are obtained. These solutions would contribute to studying the behavior and blow up properties of the solution of the Kadomtsev-Petviashvili Equation.
Prognostic and Predictive Value of CpG Island Methylator Phenotype in Patients with Locally Advanced Nonmetastatic Sporadic Colorectal Cancer
Yuwei Wang,Yadong Long,Ye Xu,Zuqing Guan,Peng Lian,Junjie Peng,Sanjun Cai,Guoxiang Cai
Gastroenterology Research and Practice , 2014, DOI: 10.1155/2014/436985
Abstract: Purpose. In the present study, the prognostic significance of CpG island methylator phenotype (CIMP) in stage II/III sporadic colorectal cancer was evaluated using a five-gene panel. Methods. Fifty stage II/III colorectal cancer patients who received radical resection were included in this study. Promoter methylation of p14ARF, hMLH1, p16INK4a, MGMT, and MINT1 was determined by methylation specific polymerase chain reaction (MSP). CIMP positive was defined as hypermethylation of three or more of the five genes. Impact factors on disease-free survival (DFS) and overall survival (OS) were analyzed using Kaplan-Meier method (log-rank test) and adjusted Cox proportional hazards model. Results. Twenty-four percent (12/50) of patients were characterized as CIMP positive. Univariate analysis showed stage III ( ) and CIMP positive ( ) patients who had significantly inferior DFS. In Cox regression analysis, CIMP positive epigenotype was independently related with poor DFS with HR = 2.935 and 95% CI: 1.193–7.220 ( ). In patients with CIMP positive tumor, those receiving adjuvant chemotherapy had a poor DFS than those without adjuvant chemotherapy ( ). Conclusions. CIMP positive was significantly correlated with decreased DFS in stage II/III colorectal cancer. Patients with CIMP positive locally advanced sporadic colorectal cancers may not benefit from 5-fluorouracil based adjuvant chemotherapy. 1. Introduction Colorectal cancer is a major cause of mortality and morbidity throughout the world. With adjuvant chemotherapy as standard management following surgery to treat stage III and stage II patients with high risk factors, the 5-year relative survival rate of locally advanced colorectal cancer was still 69.2% compared with 90.1% among patients with localized disease [1], which highlighted the need of better prognostic and predictive markers to identify those high-risk individuals. Promoter CpG island hypermethylation resulting in the transcriptional silencing of tumor suppressor genes has been widely observed in colorectal cancer and been increasingly recognized to contribute to the pathogenesis of colorectal cancer. The subset of colorectal cancers with exceptionally high frequency of CpG island methylation were referred to as CpG island methylator phenotype (CIMP) [2] and showed distinct clinicopathological characteristics [3–5]. Tumor-specific hypermethylated loci of p14ARF, hMLH1, p16INK4a, MGMT, and MINT1 were proved to be closely related with colorectal cancers [2, 6]. However, the prognostic and predictive value of CIMP in sporadic locally advanced
The Importance of Neutrophil to Lymphocyte Ratio and Peripheral Blood Eosinophilia in Chronic Obstructive Pulmonary Disease Patients with Acute Exacerbation: Recent Studies  [PDF]
Abdullahi Hassan Abdinur, Yadong Gao
Open Journal of Respiratory Diseases (OJRD) , 2019, DOI: 10.4236/ojrd.2019.92004
Abstract: Chronic obstructive pulmonary disease (COPD) is a chronic, progressive respiratory disease and the third leading cause of respiratory disease mortality. The diagnosis of COPD is changed to acute exacerbation of COPD (AECOPD) when respiratory symptoms become worse, beyond normal day-to-day variations and severely enough that changes in medication are required. Both neutrophils to lymphocyte ratio (NLR) and peripheral blood eosinophilia (PBE) are rapid and relatively inexpensive tests that can be easily applied in the clinical practice for the diagnosis and treatment of AECOPD patients. Furthermore, current studies found that NLR and PBE had a higher accuracy rate than other traditional markers (Leukocyte count and C-reactive protein) for the diagnosis and management of AECOPD. Besides, recent studies determined that NLR and PBE can be used for prediction of future exacerbations in COPD patients. This review aims to explore the current knowledge about the significance of NLR and PBE in AECOPD patients.
Consistent Valuation of Bespoke CDO Tranches
Yadong Li
Quantitative Finance , 2010,
Abstract: This paper describes a consistent and arbitrage-free pricing methodology for bespoke CDO tranches. The proposed method is a multi-factor extension to the (Li 2009) model, and it is free of the known flaws in the current standard pricing method of base correlation mapping. This method assigns a distinct market factor to each liquid credit index and models the correlation between these market factors explicitly. A low-dimensional semi-analytical Monte Carlo is shown to be very efficient in computing the PVs and risks of bespoke tranches. Numerical examples show that resulting bespoke tranche prices are generally in line with the current standard method of base correlation with TLP mapping. Practical issues such as model deltas and quanto adjustment are also discussed as numerical examples.
A Dynamic Correlation Modelling Framework with Consistent Stochastic Recovery
Yadong Li
Quantitative Finance , 2010,
Abstract: This paper describes a flexible and tractable bottom-up dynamic correlation modelling framework with a consistent stochastic recovery specification. The stochastic recovery specification only models the first two moments of the spot recovery rate as its higher moments have almost no contribution to the loss distribution and CDO tranche pricing. Observing that only the joint distribution of default indicators is needed to build the portfolio loss distribution, we propose a generic class of default indicator copulas to model CDO tranches, which can be easily calibrated to index tranche prices across multiple maturities. This correlation modelling framework has the unique advantage that the joint distribution of default time and other dynamic properties of the model can be changed separately from the loss distribution and tranche prices. After calibrating the model to index tranche prices, existing top-down methods can be applied to the common factor process to construct very flexible systemic dynamics without changing the already calibrated tranche prices. This modelling framework therefore combines the best features of the bottom-up and top-down models: it is fully consistent with all the single name market information and it admits very rich and flexible spread dynamics. Numerical results from a non-parametric implementation of this modelling framework are also presented. The non-parametric implementation achieved fast and accurate calibration to the index tranches across multiple maturities even under extreme market conditions. A conditional Markov chain method is also proposed to construct the systemic dynamics, which supports an efficient lattice pricing method for dynamic spread instruments. We also showed how to price tranche options as an example of this fast lattice method.
Nonconforming H1-Galerkin Mixed Finite Element Method for Pseudo-Hyperbolic Equations  [PDF]
Yadong Zhang, Yuqi Niu, Dongwei Shi
American Journal of Computational Mathematics (AJCM) , 2012, DOI: 10.4236/ajcm.2012.24036
Abstract: Based on H1-Galerkin mixed finite element method with nonconforming quasi-Wilson element, a numerical approximate scheme is established for pseudo-hyperbolic equations under arbitrary quadrilateral meshes. The corresponding optimal order error estimate is derived by the interpolation technique instead of the generalized elliptic projection which is necessary for classical error estimates of finite element analysis.
Analysis on Correlation between Resistin—420C/G Polymorphism and Type 2 Diabetes Mellitus Macroangiopathy in Han Population of Northeast China  [PDF]
Bingxue Qi, Ma Yan, Yadong Sun
Journal of Biosciences and Medicines (JBM) , 2017, DOI: 10.4236/jbm.2017.512003
Abstract:
Objective: To study the allelic and genotypic frequency distribution of RETN—420C/G single nucleotide polymorphisms (SNPs) and its relationship with type 2 diabetes mellitus (T2DM) complicated with macroangiopathy in Han population of northeast China. Methods: The genotypes and their frequencies of a total of 180 cases, including 60 cases of T2DM complicated with macroangiopathy, 60 cases of simple T2DM and 60 cases of normal control (ND), were measured by PCR—RFLP. Results: The allelic frequencies and simple CC/GC + GG genotype in T2DM complicated with macroangiopathy group were significant different compared with ND group (P < 0.01). The allelic frequencies and CC/GC + GG genotype in T2DM complicated with macroangiopathy group were significant different compared with T2DM group (P < 0.05). The GC + GG genotype in T2DM complicated with macroangiopathy group was significantly higher than that in T2DM group (P < 0.05). Conclusion: The RETN—420C/G polymorphism has a correlation with the occurrence of T2DM complicated with macroangiopathy in Han population of northeast China.
The B?cklund Transformations and Abundant Exact Explicit Solutions for a General Nonintegrable Nonlinear Convection-Diffusion Equation
Yong Huang,Yadong Shang
Abstract and Applied Analysis , 2012, DOI: 10.1155/2012/489043
Abstract: The B?cklund transformations and abundant exact explicit solutions for a class of nonlinear wave equation are obtained by the extended homogeneous balance method. These solutions include the solitary wave solution of rational function, the solitary wave solutions, singular solutions, and the periodic wave solutions of triangle function type. In addition to rederiving some known solutions, some entirely new exact solutions are also established. Explicit and exact particular solutions of many well-known nonlinear evolution equations which are of important physical significance, such as Kolmogorov-Petrovskii-Piskunov equation, FitzHugh-Nagumo equation, Burgers-Huxley equation, Chaffee-Infante reaction diffusion equation, Newell-Whitehead equation, Fisher equation, Fisher-Burgers equation, and an isothermal autocatalytic system, are obtained as special cases.
The Extended Hyperbolic Function Method for Generalized Forms of Nonlinear Heat Conduction and Huxley Equations
Yong Huang,Yadong Shang
Journal of Applied Mathematics , 2012, DOI: 10.1155/2012/769843
Abstract: The extended hyperbolic function method is used to derive abundant exact solutions for generalized forms of nonlinear heat conduction and Huxley equations. The extended hyperbolic function method provides abundant solutions in addition to the existing ones. Some previous results are supplemented and extended greatly.
The First-Integral Method and Abundant Explicit Exact Solutions to the Zakharov Equations
Yadong Shang,Xiaoxiao Zheng
Journal of Applied Mathematics , 2012, DOI: 10.1155/2012/818345
Abstract: This paper is concerned with the system of Zakharov equations which involves the interactions between Langmuir and ion-acoustic waves in plasma. Abundant explicit and exact solutions of the system of Zakharov equations are derived uniformly by using the first integral method. These exact solutions are include that of the solitary wave solutions of bell-type for n and E, the solitary wave solutions of kink-type for E and bell-type for n, the singular traveling wave solutions, periodic wave solutions of triangle functions, Jacobi elliptic function doubly periodic solutions, and Weierstrass elliptic function doubly periodic wave solutions. The results obtained confirm that the first integral method is an efficient technique for analytic treatment of a wide variety of nonlinear systems of partial differential equations.
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