DYNAMICS OF A HEPATITIS B MODEL WITH SATURATED INCIDENCE

In this article, we present a hepatitis B epidemic model with saturated incidence.The dynamic behaviors of the deterministic and stochastic system are studied. To thisend, we first establish the local and global stability conditions of the equilibrium of thedeterministic model. Second, by constructing suitable stochastic Lyapunov functions, thesufficient conditions for the existence of ergodic stationary distribution as well as extinctionof hepatitis B are obtained.

DYNAMIC FOR A STOCHASTIC MULTI-GROUP AIDS MODEL WITH SATURATED INCIDENCE RATE

In this paper,a stochastic multi-group AIDS model with saturated incidence rate is studied.We prove that the system is persistent in the mean under some parametric restrictions.We also obtain the sufficient condition for the existence of the ergodic stationary distribution of the system by constructing a suitable Lyapunov function.Our results indicate that the existence of ergodic stationary distribution does not rely on the interior equilibrium of the corresponding deterministic system,which greatly improves upon previous results.

High Expression of the RECK Gene in Breast Cancer Cells is Related to Low Invasive Capacity

OBJECTIVE To investigate the expression of the RECK gene in human breast （cancer） cell lines, and to determine the relationship between RECK gene expression and the invasive capacity of the breast cancer cell lines.METHODS The invasive capacity of breast （cancer） cell lines including HBL-100, MCF-7 and MDA-MB-435S were determined by the Tran- swell method. The protein expression levels of RECK, MMP-2 and MMP- 9 genes in these three cell lines were measured by immunocytochemical methods. The expressions of the RECK gene and protein level were measured hv RT-PCR and Westrn hints in the cell lines respectively.RESULTS The order of the nvasive capacity of the breast （cancer） cell lines was MDA-MB-435S, being the highest, and HBL-100, being the lowest. The invasive capacity difference between any two groups among the three groups was significant （P〈0.01）. The protein expression level of the RECK gene in the HBL-100 cell line was highest, and no expression was detected in MDA-MB-435S cells. Moreover, the expression of the RECK gene was negatively correlated with the expression of the MMP-2 and MMP-9 genes. The mRNA level of the RECK gene in HBL-100 cells was the highest, but no expression was found in the MDA-MB-435S cells （P〈0.001）.CONCLUSION There was a significant negative correlation between the expression level of the RECK gene and invasive capacity in vitro, and the RECK gene expression showed an inverse proportion to that of the MMP-2, MMP-9 genes.

Iron-based metal-organic framework as a dual cooperative release system for enhanced vascularization and bone regeneration

Vascularization and bone regeneration are closely related in the process of bone remodeling,and designing a bioactive scaffold with pro-angiogenic and osteogenic properties may accelerate the repair of bone defects.In this work,an iron-based metal-organic framework(MIL-88)was developed as a carrier for loading a pro-angiogenic small molecular drug(dimethyloxallyl glycine,DMOG),and then embedded into the PLGA nanofibrous scaffolds to repair cranial defects in rats.Imaging and histological evaluation indicated that PLGA/MIL@D scaffold markedly enhanced vascularization and bone regeneration in vivo.Moreover,in vitro assay showed that co-delivery system significantly promoted angiogenesis by stimulating endothelial cell migration,tube formation,and enhanced osteogenesis by promoting expression of osteoblast related proteins.In addition,PLGA/MIL@D scaffold promotes angiogenesis by activating the hypoxia-inducible factor-1(HIF-1)/vascular endothelial growth factor(VEGF)signaling pathway.Altogether,this bioactive PLGA/MIL@D scaffold can combine angiogenesis with osteogenesis,and will be a bright strategy for the repair of bone defects.

Integration exosomes with MOF-modified multifunctional scaffold for accelerating vascularized bone regeneration

Designing a multifunctional scaffold with osteogenic and angiogenic properties holds promise for ideal bone regeneration. Innovative scaffold was here constructed by immobilizing exosomes derived from human bone mesenchymal stem cells(h BMSCs) onto porous polymer meshes which developed by PLGA and Cu-based MOF(PLGA/Cu BDC@Exo). The synthesized exosome-laden scaffold capable of providing a dual cooperative controllable release of bioactive copper ions and exosomes that promote osteogenesis and angiogenesis, thereby achieving cell-free bone regeneration. In vitro assay revealed the composite stent not only substantially upregulated the expression of osteogenic-related proteins(ALP, Runx2, Ocn)and VEGF in h BMSCs, but promoted the migration and tube formation of the human umbilical vein endothelial cells(HUVECs). In vivo evaluation further confirmed this scaffold dramatically stimulated bone regeneration and angiogenesis in critical-sized defects in rats. Altogether, this composite scaffold carrying therapeutic exosomes had an osteogenic-angiogenic coupling effect and offered a new idea for cell-free bone tissue engineering.

不同经营模式山核桃林地土壤pH值、养分与细菌多样性的差异

为探究土壤细菌多样性及其功能对山核桃(Carya cathayensis)经营模式的指导作用,本文采用16S r RNA基因高通量测序技术检测并比较了生态经营和过度经营的山核桃林土壤中的细菌群落,分析了山核桃干腐病发病期干腐病感病指数、土壤pH值、养分与细菌多样性的相关性。结果表明:(1)生态经营山核桃林的感病指数(3.3±3.35)显著低于过度经营山核桃林(81.9±1.27)。(2)生态经营山核桃林土壤pH(6.64±0.06)显著高于过度经营山核桃林(5.80±0.04)。(3)过度经营山核桃林土壤的速效磷、速效钾和速效氮含量分别为18.10±0.58 mg/kg、698.63±11.24mg/kg和227.13±3.81 mg/kg,均分别显著高于三者在生态经营山核桃林土壤中的含量(14.94±0.27 mg/kg、497.13±6.19 mg/kg和195.28±6.01 mg/kg)。(4)生态经营和过度经营山核桃林土壤分别有14和21个主要细菌属,其中鞘氨醇单胞菌属(Sphingomonas)、Gaiella和溶杆菌属(Lysobacter)为生态经营山核桃林土壤的优势属,其相对多度显著高于过度经营山核桃林;而Bryobacter、Candidatus Solibacter和慢生根瘤菌属(Bradyrhizobium)为过度经营山核桃林土壤中的优势属,其相对多度显著高于生态经营山核桃林。两种经营模式下山核桃林土壤的OTUs、Ace指数、Chao指数、Shannon指数和Simpson指数无显著差异。RDA分析与蒙特卡罗检验表明,p H值、速效磷和速效氮均对土壤细菌优势菌群群落结构有显著影响(P<0.05)。

Exosome-functionalized magnesium-organic framework-based scaffoldswith osteogenic, angiogenic and anti-inflammatory properties foraccelerated bone regeneration

Exosomes derived from human adipose-derived stem cells (hADSCs-Exos) have shown potential as an effectivetherapeutic tool for repairing bone defects. Although metal-organic framework (MOF) scaffolds are promisingstrategies for bone tissue regeneration, their potential use for exosome loading remains unexplored. In this study,motivated by the potential advantages of hADSCs-Exos and Mg-GA MOF, we designed and synthesized anexosome-functionalized cell-free PLGA/Mg-GA MOF (PLGA/Exo-Mg-GA MOF) scaffold, taking using of thebenefits of hADSCs-Exos, Mg2+, and gallic acid (GA) to construct unique nanostructural interfaces to enhanceosteogenic, angiogenic and anti-inflammatory capabilities simultaneously. Our in vitro work demonstrated thebeneficial effects of PLGA/Exo-Mg-GA MOF composite scaffolds on the osteogenic effects in human bonemarrow-derived mesenchymal stem cells (hBMSCs) and angiogenic effects in human umbilical endothelial cells(HUVECs). Slowly released hADSCs-Exos from composite scaffolds were phagocytosed by co-cultured cells,stabilized the bone graft environment, ensured blood supply, promoted osteogenic differentiation, and acceleratedbone reconstruction. Furthermore, our in vivo experiments with rat calvarial defect model showed thatPLGA/Exo-Mg-GA MOF scaffolds promoted new bone formation and satisfactory osseointegration. Overall, weprovide valuable new insights for designing exosome-coated nanocomposite scaffolds with enhanced osteogenesisproperty.

Dynamics of stochastic predator-prey models with distributed delay and stage structure for prey

In this paper,we analyze two stochastic predator-prey models with distributed delay and stage structure for prey.For the nonautonomous periodic case of the model,by using Khasminskii’s theory of periodic solution,we show that the system has at least one positive T-periodic solution.For the model which is disturbed by both white and telegraph noises,we obtain sufficient criteria for positive recurrence of the solutions to the model by constructing a suitable stochastic Lyapunov function with regime switching.The positive recurrence implies that both prey and predator populations will be persistent in the long term.

Stationary distribution and periodic solution of stochastic chemostat models with single-species growth on two nutrients

In this paper,we consider two chemostat models w th random perturbation,in which single species depends on two perfectly substitutable resources for growth.For the autonomous system,we first prove that the solution of the system is positive and global.Then we establish sufficient conditions for the existence of an ergodic stationary distribu tion by constructing appropriate Lyapunov functions-For the non-autonomous system,by using Mas'minskii theory on periodic Markov processes,we derive it admits a nontriv ial positive periodic solution.Finally,numerical simulations are carried out to illustrate our main results.

The stationary distribution and extinction of a double thresholds HTLV-I infection model with nonlinear CTL immune response disturbed by white noise

This paper investigates the stochastic HTLV-I infection model with CTL immune response,and the corresponding deterministic model has two basic reproduction numbers.We consider the nonlinear CTL immune response for the interaction between the virus and the CTL immune cells.Firstly,for the theoretical needs of system dynamical behavior,we prove that the stochastic model solution is positive and global.In atldition,we obtain the existence of ergodic stationary distribution by stochastic Lyapunov functions.Meanwhile,sufficient condition for the extinction of the stochastic system is acquired.Reasonably,the dynamical behavior of deterministic model is included in our result of stochastic model when the white noise disappears.

Dynamics of a stochastic rabies epidemic model with Markovian switching

In this paper,we analyze a stochastic rabies epidemic model which is perturbed by both white noise and telegraph noise.First,we prove the existence of the unique global positive solution.Second,by constructing an appropriate Lyapunov function,we establish a sufficient condition for the existence of a unique ergodic stationary distribution of the positive solutions to the model.Then we establish sufficient conditions for the extinction of diseases.Finally,numerical simulations are introduced to illustrate our theoretical results.

The asymptotic behavior of a stochastic multigroup SIS model

In this paper, we explore the long time behavior of a multigroup Susceptible-Infected Susceptible （SIS） model with stochastic perturbations. The conditions for the disease to die out are obtained. Besides, we also show that the disease is fluctuating around the endemic equilibrium under some conditions. Moreover, there is a stationary distribution under stronger conditions. At last, some numerical simulations are applied to support our theoretical results.

DYNAMICS OF AN HIV-1 INFECTION MODEL WITH CELL-MEDIATED IMMUNE RESPONSE AND STOCHASTIC PERTURBATION

In this paper, we introduce the stochasticity into an HIV-1 infection model with cytotoxic T lymphocytes （CTLs） immune response via the technique of parameter perturbation. We show that there is a positive solution as desired in any population dynamics. Then we analyze the long time behavior of this model. We obtain a sufficient condition for the stochastic asymptotic stability in the large of the infection-free equilibrium and give the conditions for the solution fluctuating around the two infection equilibria （one without CTLs being activated and the other with）. Finally, we make sinmlations to conform to our analytical results.

ANALYSIS OF A PREDATOR-PREY MODEL WITH DISEASE IN THE PREY

In this paper, we discuss the behavior of a predator-prey model with disease in the prey with and without stochastic perturbation, respectively. First, we briefly give the dynamic of the deterministic system, by analyzing stabilities of its four equilibria. Then, we consider the asymptotic behavior of the stochastic system. By Lyapunov analysis methods, we show the stochastic stability and its long time behavior around the equi- librium of the deterministic system. We obtain there are similar properties between the stochastic system and its corresponding deterministic system, when white noise is small. But large white noise can make a unstable deterministic system to be stable.

The asymptotic behavior and ergodicity of stochastically perturbed SVIR epidemic model

In this paper, we introduce stochasticity into an SIR epidemic model with vaccina- tion. The stochasticity in the model is a standard technique in stochastic population modeling. When the perturbations are small, by the method of stochastic Lyapunov functions, we carry out a detailed analysis on the dynamical behavior of the stochastic model regarding of the basic reproduction number R0. If R0 ≤ 1, the solution of the model is oscillating around a steady state, which is the disease-free equilibrium of the corresponding deterministic model. If R0 〉 1, there is a stationary distribution and the solution has the ergodic property, which means that the disease will prevail.

Dynamical behavior of a stochastic multigroup staged-progression HIV model with saturated incidence rate and higher-order perturbations

In this paper,we analyze a higher-order stochastically perturbed multigroup staged-progression model for the transmission of HlV with saturated incidence rate.We obtainsufficient conditions for the existence and uniqueness of an ergodic stationary distribu-tion of positive solutions to the system by establishing a suitable stochastic Lyapunovfunction.In addition,we make up adequate conditions for complete eradication and wip-ing out the infectious disease.In a biological interpretation,the existence of a stationarydistribution implies that the disease will prevail and persist in the long term.Finally,examples and numerical simulations are introduced to validate our theoretical results.

Stationary distribution and extinction for a stochastic two-compartment model of B-cell chronic lymphocytic leukemia

In this paper,we study the dynamical behavior of a stochastic two-compartment model of B-cell chronic lymphocytic leukemia,which is perturbed by white noise.Firstly,by constructing suitable Lyapunov functions,we establish sufficient conditions for the existence of a unique ergodic stationary distribution.Then,conditions for extinction of the disease are derived.Furthermore,numerical simulations are presented for supporting the theoretical results.Our results show that large noise intensity may contribute to extinction of the disease.

Dynamics of an autonomous Gilpin-Ayala competition model with random perturbation

This paper discusses the dynamics of a Gilpin-Ayala competition model of two interact­ing species perturbed by white noise.We obtain the existence of a unique global positive solution of the system and the solution is bounded in pth moment.Then,we establish sufficient and necessary conditions for persistence and the existence of an ergodic sta­tionary distribution of the model.We also establish sufficient conditions for extinction of the model.Moreover,numerical simulations are carried out for further support of present research.