Dynamics of a higher order rational difference equation

Yanqin Wang 한국전산응용수학회 2009 Journal of applied mathematics & informatics Vol.27 No.3

In this paper, we investigate the invariant interval, periodic character, semicycle and global attractivity of all positive solutions of the equation yn+1 =<수식> , n = 0, 1, . . . , where the parameters p, q, r and the initial conditions y−k, . . . , y−1, y0 are positive real num- bers, k ∈ {1, 2, 3, . . . }.It is worth to mention that our results solve the open problem proposed by Kulenvic and Ladas in their monograph [Dynamics of Second Order Rational Difference Equations: with Open Problems and Conjectures, Chapman & Hall/CRC, Boca Raton, 2002] In this paper, we investigate the invariant interval, periodic character, semicycle and global attractivity of all positive solutions of the equation yn+1 =<수식> , n = 0, 1, . . . , where the parameters p, q, r and the initial conditions y−k, . . . , y−1, y0 are positive real num- bers, k ∈ {1, 2, 3, . . . }.It is worth to mention that our results solve the open problem proposed by Kulenvic and Ladas in their monograph [Dynamics of Second Order Rational Difference Equations: with Open Problems and Conjectures, Chapman & Hall/CRC, Boca Raton, 2002]

DYNAMICS OF A HIGHER ORDER RATIONAL DIFFERENCE EQUATION

Wang, Yanqin The Korean Society for Computational and Applied M 2009 Journal of applied mathematics & informatics Vol.27 No.3

In this paper, we investigate the invariant interval, periodic character, semicycle and global attractivity of all positive solutions of the equation $Y_{n+1}\;=\;\frac{p+qy_{n-k}}{1+y_n+ry_{n-k}}$, n = 0, 1, ..., where the parameters p, q, r and the initial conditions $y_{-k}$, ..., $y_{-1}$, $y_0$ are positive real numbers, k $\in$ {1, 2, 3, ...}. It is worth to mention that our results solve the open problem proposed by Kulenvic and Ladas in their monograph [Dynamics of Second Order Rational Difference Equations: with Open Problems and Conjectures, Chapman & Hall/CRC, Boca Raton, 2002]

GLOBAL STABILITY OF A NONLINEAR DIFFERENCE EQUATION

YanQin Wang 한국전산응용수학회 2011 Journal of applied mathematics & informatics Vol.29 No.3

In this paper, we investigate the local asymptotic stability, the invariant intervals, the global attractivity of the equilibrium points, and the asymptotic behavior of the solutions of the difference equation [수식]n = 0, 1, . . . , where the parameters a, b, A, B, C and the initial conditions x_(-k), . . . , x_(-1), x_0 are positive real numbers.

GLOBAL STABILITY OF A NONLINEAR DIFFERENCE EQUATION

Wang, Yanqin The Korean Society for Computational and Applied M 2011 Journal of applied mathematics & informatics Vol.29 No.3

In this paper, we investigate the local asymptotic stability, the invariant intervals, the global attractivity of the equilibrium points, and the asymptotic behavior of the solutions of the difference equation $x_{n+1}=\frac{a+bx_nx_{n-k}}{A+Bx_n+Cx_{n-k}}$, n = 0, 1,${\ldots}$, where the parameters a, b, A, B, C and the initial conditions $x_{-k}$, ${\ldots}$, $x_{-1}$, $x_0$ are positive real numbers.

Prognostic Value of TP53 Mutation for Transcatheter Arterial Chemoembolization Failure/Refractoriness in HBV-Related Advanced Hepatocellular Carcinoma

Miao Xue,Yanqin Wu,Wenzhe Fan,Jian Guo,Jialiang Wei,Hongyu Wang,Jizhou Tan,Yu Wang,Wang Yao,Yue Zhao,Jiaping Li 대한암학회 2020 Cancer Research and Treatment Vol.52 No.3

Purpose This study aimed to investigate the clinicopathologic features and mutational landscape of patients with hepatitis B virus (HBV)–related advanced hepatocellular carcinomas (HCC) undergoing transcatheter arterial chemoembolization (TACE). Materials and Methods From January 2017 to December 2018, 38 patients newly diagnosed with HBV-related advanced HCC were enrolled in the final analysis. Their pathological tissues and corresponding blood samples before TACE treatment were collected for whole-exome sequencing. Response to TACE was evaluated at 1-3 months after two consecutive use of TACE. Predictive factors were analyzed by univariate and multivariate analyses in a bivariate Logistic regression model. Enrichment of related pathways of all driver genes were acquired using the gene set enrichment analysis (GSEA). Results Among 38 patients, 23 (60.5%) exhibited TACE failure/refractoriness. Patients with TACE failure/refractoriness showed higher frequency of TP53 mutation than their counterparts (p=0.020). Univariate and multivariate analyses showed that only vascular invasion and TP53mutation were significantly correlated with TACE failure/refractoriness in HBV-related advanced HCC. Of the 16 patients without vascular invasion, eight (50.0%) had TP53 mutations, and TP53mutation was associated with TACE failure/refractoriness (p=0.041). Moreover, GSEA showed that mitogen-activated protein kinase and apoptosis pathways induced by TP53 mutation were possibly associated with TACE failure/refractoriness. Conclusion Our study suggested that TP53 mutation was independently related with TACE efficacy, which may work via mitogen-activated protein kinase and apoptosis pathways. These findings may provide evidence to help distinguish patients who will particularly benefit from TACE from those who require more personalized therapeutic regimens and rigorous surveillance in HBV-related advanced HCC.

Isolation and Characterization of a Novel Bacterium Burkholderia gladioli Bsp-1 Producing Alkaline Lipase

( Jing Zhu ),( Yanjing Liu ),( Yanqin ),( Lixia Pan ),( Yi Li ),( Geliang ),( Qingyan Wang ) 한국미생물·생명공학회 2019 Journal of microbiology and biotechnology Vol.29 No.7

Active lipase-producing bacterium Burkholderia gladioli Bps-1 was rapidly isolated using a modified trypan blue and tetracycline, ampicillin plate. The electro-phoretically pure enzyme was obtained by purification using ethanol precipitation, ion-exchange chromatography, and gel filtration chromatography. The molecular weight was 34.6 kDa and the specific activity was determined to be 443.9 U/mg. The purified lipase showed the highest activity after hydrolysis with p-NPC₁₆ at a pH of 8.5 and 50°C, and the K_m, k_cat, and k_cat/K_m values were 1.05 mM, 292.95 s^-1 and 279 s^-1mM^-1, respectively. The lipase was highly stable at 7.5 ≤ pH ≤ 10.0. K⁺ and Na⁺ exerted activation effects on the lipase which had favorable tolerance to short-chain alcohols with its residual enzyme activity being 110% after being maintained in 30% ethanol for 1 h. The results demonstrated that the lipase produced by the strain B. gladioli Bps-1 has high enzyme activity and is an alkaline lipase. The lipase has promising chemical properties for a range of applications in the food-processing and detergent industries, and has particularly high potential for use in the manufacture of biodiesel.

The molybdenum species of MoO3/SiO2 and their catalytic activities for the epoxidation of propylene with cumene hydroperoxide

Yongxia Miao,Xiaohui Liu,Yanglong Guo,Yanqin Wang,Yun Guo,Guanzhong Lu 한국공업화학회 2010 Journal of Industrial and Engineering Chemistry Vol.16 No.1

The MoO3/SiO2 catalysts containing different surface molybdenum species were prepared by a sol–gel method, and the effects of the preparation condition and MoO3 loading on the surface molybdenum species and property of MoO3/SiO2 were studied. The XRD, FT-IR, UV–vis and Raman spectroscopies were used to characterize the surface molybdenum species, and temperature-programmed desorption of NH3 adsorbed on a catalyst was used to detect the surface acidic properties. The results show that, therewere the dispersed polymolybdate, a-MoO3, b-MoO3, monomeric molybdenum species and silicomolybdic acid on the MoO3/SiO2 catalyst, and their distributions and subsistence states were affected by the preparation condition and MoO3 loading. Different molybdenum species exhibit different catalytic activities for the epoxidation of propylene with cumene hydroperoxide. In the 15 wt% MoO3/SiO2 catalyst synthesized at pH 9.1 and dried appropriately, there are the small size b-MoO3 and monomeric molybdenum species that they are mainly effective catalyst components for the epoxidation of propylene. Using this catalyst, the ~100% conversion of cumene hydroperoxide and ~100% selectivity to propylene oxide can be obtained in the tert-butyl alcohol solvent at 2.6 MPa and 80 8C for 4 h.

Influences of Pd precursors and preparation method on the catalytic performances of Pd-only close-coupled catalysts

Zengzan Zhu,Yun Guo,Yanglong Guo,Zhigang Zhang,Yanqin Wang,Guanzhong Lu 한국공업화학회 2012 Journal of Industrial and Engineering Chemistry Vol.18 No.6

The properties and stabilities of Pd/Al2O3 close-coupled catalysts prepared with different methods and Pd precursors (PdCl2, Pd(NO3)2, and Pd(NH3)2(NO2)2) have been investigated, and characterized by N2adsorption at low temperature, H2 chemical adsorption, X-ray diffraction (XRD), H2 temperature programmed reduction (H2-TPR), transmission electron microscopy (TEM) and three-way catalytic activity testing. The results show that the catalyst prepared by a prefabricate method with Pd(NH3)2(NO2)2 precursor behaves higher catalytic activity and thermal stability for removing HC, CO and NOx, due to its higher BET surface area, higher Pd dispersion, smaller Pd particle sizes. And the prefabricate method can lead to stronger interaction between the Pd active species and the support by means of a strong electrostatic attraction and ion/ligand-exchange between the Pd complexes and the support surface, which restrict the remotion and sintering of Pd active particles at high temperature. Therefore, a prefabricate method is more suited to preparing close-coupled catalysts than a traditional impregnation method.

Functional characterization of the CfAOC and CfJMT gene promoters related to MeJA biosynthesis in Cymbidium faberi

Zhou Yin,Xu Zheng,Chen Xu,Zhou Junjiang,Wang Songtai,Xu Yanqin 한국식물생명공학회 2023 Plant biotechnology reports Vol.17 No.2

Oriental orchids of the genus Cymbidium are famous for their flower fragrance and have great value in the horticultural market. To investigate the regulatory mechanisms of fragrance biosynthesis in Cymbidium faberi, the promoters of the CfAOC and CfJMT genes in the methyl jasmonate biosynthesis pathway were cloned and analyzed. Notably, the CfAOC promoter was transcriptionally active in all vegetative organs, which was not true for the CfJMT promoter, indicating that the latter is tissue-specific for the flowers of C. faberi. The dual-luciferase assay showed that the fragment between –629 and –1038 nt of the CfAOC promoter, as well as the fragment between –960 and –1121 nt of the CfJMT promoter, displayed specific interaction with the CfbHLH transcription factors. These results provide a theoretical basis for the genetic modification of the flower fragrance of Cymbidium based on specific CfbHLH transcription factors.