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A novel IVGTT model including interstitial insulin 包括间质胰岛素在内的新型IVGTT模型
Q4 MATHEMATICS, APPLIED Pub Date : 2023-02-20 DOI: 10.5206/mase/15505
Jiaxu Li, Jin Jun, Xu Rui, Yu Lei, Jin Zhen
Minimal Model (MM) is the top-scoring model for assessing physiological characteristics to diagnose the potential or onset of type 2 diabetes mellitus (T2DM) through the intravenous glucose tolerance test (IVGTT) for the past four decades. Nevertheless it has been arguable that MM method either overestimates glucose effectiveness (GE) or underestimates insulin sensitivity (IS) in some cases by both biologists through in vivo experiments and mathematicians by analysis and/or simulations. We propose a novel model including the interstitial insulin according to physiology and adapted from the well accepted Sturis’ model for the glucose-insulin metabolic system suitable to the IVGTT setting. Our model consistently overcomes the aforementioned defects in a subgroup of subjects. In addition, the variable X for insulin action in MM might be appropriately interpreted as an increment of insulin in the interstitial space in response to the bolus stimulus, rather than being proportional to the interstitial insulin as believed.
最小模型(MM)是过去四十年来通过静脉葡萄糖耐量试验(IVGTT)评估生理特征以诊断2型糖尿病(T2DM)的潜在或发病的最高评分模型。然而,生物学家通过体内实验和数学家通过分析和/或模拟,在某些情况下,MM方法要么高估了葡萄糖有效性(GE),要么低估了胰岛素敏感性(IS),这是有争议的。我们根据生理学提出了一种新的模型,包括间质胰岛素,并改编自公认的Sturis模型,用于适合IVGTT环境的葡萄糖-胰岛素代谢系统。我们的模型一致地克服了受试者亚组中的上述缺陷。此外,MM中胰岛素作用的变量X可以适当地解释为间质空间中胰岛素对推注刺激的反应增加,而不是与间质胰岛素成比例。
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引用次数: 0
Fisher information approach to understand the Gompertz model 理解Gompertz模型的Fisher信息方法
Q4 MATHEMATICS, APPLIED Pub Date : 2022-12-26 DOI: 10.5206/mase/15447
A. Al-Saffar, Eun-jin Kim
As a measure of sustainability, Fisher information is employed in the Gompertz growth model. The effect of different oscillatory modulations is examined on the system's evolution and Probability Density Function (PDF). For a sufficiently large frequency of periodic fluctuations occurring in both positive and negative feedbacks, the system maintains its initial conditions. A similar PDF is shown regardless of the initial values when there are periodic fluctuations in positive feedback. By periodic fluctuations in negative feedback, the Gompertz model can lose its self-organization. Finally, despite the fact that the Gompertz and logistic systems evolve differently over time, the results show that they are exceptionally similar in terms of information and sustainability.
作为可持续性的衡量标准,Fisher信息被用于Gompertz增长模型。研究了不同振荡调制对系统演化和概率密度函数(PDF)的影响。对于在正反馈和负反馈中发生的周期性波动的足够大的频率,系统保持其初始条件。当正反馈中存在周期性波动时,无论初始值如何,都会显示类似的PDF。由于负反馈的周期性波动,Gompertz模型可能会失去自组织性。最后,尽管Gompertz和物流系统随着时间的推移发展不同,但结果表明,它们在信息和可持续性方面异常相似。
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引用次数: 1
A study on the mild solution of special random impulsive fractional differential equations 一类特殊随机脉冲分数阶微分方程温和解的研究
Q4 MATHEMATICS, APPLIED Pub Date : 2022-12-14 DOI: 10.5206/mase/14985
Sayooj Aby Jose, Varun Bose C S, Bijesh P Biju, Abin Thomas Nirappathu house
In this article, we deal with mild solution of special random impulsive fractional differential equations. Initially, we present the existence of the mild solution via Leray-Schauder fixed point method. After that, we establish the exponential stability of the system. Finally, we give examples to illustrate the effectiveness of the theoretical results.
本文讨论了一类特殊随机脉冲分数阶微分方程的温和解。首先,我们通过Leray Schauder不动点方法给出了温和解的存在性。然后,我们建立了系统的指数稳定性。最后,通过实例说明了理论结果的有效性。
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引用次数: 0
Combination therapy for cancer with IL-27 and anti-PD-1: A simplified mathematical model IL-27和抗pd -1联合治疗癌症:一个简化的数学模型
Q4 MATHEMATICS, APPLIED Pub Date : 2022-12-09 DOI: 10.5206/mase/15100
Kenton D. Watt, Kang-Ling Liao
Many experiential and clinical trials in cancer treatment show that a combination of immune checkpoint inhibitor with another agent can improve the tumor reduction. Anti Programmed death 1 (Anti-PD-1) is one of these immune checkpoint inhibitors that re-activate immune cells to inhibit tumor growth.  In this work, we consider a combination treatment of anti-PD-1 and Interleukin-27 (IL-27). IL-27 has anti-cancer functions to promote the development of Th1 and CD8$^+$ T cells, but it also upregulates the expression of PD-1 and Programmed death ligand 1 (PD-L1) to inactivate these T cells. Thus, the functions of IL-27 in tumor growth is controversial. Hence, we create a simplified mathematical model to investigate whether IL-27 is pro-cancer or anti-cancer in the combination with anti-PD-1 and to what degree anti-PD-1 improves the efficacy of IL-27. Our synergy analysis for the combination treatment of IL-27 and anti-PD-1 shows that (i) ant-PD-1 can efficiently improve the treatment efficacy of IL-27; and (ii) there exists a monotone increasing function $F_c(G)$ depending on the treatment efficacy of anti-PD-1 $G$ such that IL-27 is an efficient anti-cancer agent when its dose is smaller than $F_c(G)$, whereas IL-27 is a pro-cancer agent when its dose is higher than $F_c(G)$. Our analysis also provides the existence and the local stability of the trivial, non-negative, and positive equilibria of the model. Combining with simulation, we discuss the effect of the IL-27 dosage on the equilibria and find that the T cells and IFN-$gamma$ could vanish and tumor cells preserve, when the production rate of T cells by IL-27 is low or the dosage of IL-27 is low.
癌症治疗的许多经验和临床试验表明,免疫检查点抑制剂与另一种药物的组合可以改善肿瘤的减少。抗程序性死亡1(Anti-PD-1)是这些免疫检查点抑制剂之一,可重新激活免疫细胞以抑制肿瘤生长。在这项工作中,我们考虑了抗PD-1和白细胞介素-27(IL-27)的联合治疗。IL-27具有促进Th1和CD8$^+$T细胞发育的抗癌功能,但它也上调PD-1和程序性死亡配体1(PD-L1)的表达以灭活这些T细胞。因此,IL-27在肿瘤生长中的作用是有争议的。因此,我们创建了一个简化的数学模型来研究IL-27与抗PD-1的组合是抗癌还是抗癌,以及抗PD-1在多大程度上提高了IL-27的疗效。我们对IL-27和抗PD-1联合治疗的协同作用分析表明:(i)ant-PD-1可以有效提高IL-27的治疗效果;和(ii)存在单调递增函数$F_c(G)$,其取决于抗PD-1$G$的治疗效果,使得当其剂量小于$F_c)$时,IL-27是有效的抗癌剂,而当其剂量高于$F_c。我们的分析还提供了该模型平凡平衡、非负平衡和正平衡的存在性和局部稳定性。结合模拟,我们讨论了IL-27剂量对平衡的影响,发现当IL-27产生T细胞的速率较低或IL-27剂量较低时,T细胞和IFN-γ$可以消失,肿瘤细胞可以保留。
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引用次数: 0
The existence and uniqueness of solutions of a nonlinear toxin-dependent size-structured population model 一类非线性毒素依赖大小结构种群模型解的存在唯一性
Q4 MATHEMATICS, APPLIED Pub Date : 2022-09-30 DOI: 10.5206/mase/15074
Y. Li, Qihua Huang
In this paper, we study a toxin-mediated size-structured population model with nonlinear reproduction, growth, and mortality rates. By using the characteristic method and the contraction mapping argument, we establish the existence-uniqueness of solutions to the model. We also prove the continuous dependence of solutions on initial conditions.
在本文中,我们研究了一个具有非线性繁殖、生长和死亡率的毒素介导的大小结构种群模型。利用特征方法和收缩映射论证,建立了模型解的存在唯一性。我们还证明了解对初始条件的连续依赖性。
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引用次数: 0
Global stability of a delay HCV dynamics model with cellular proliferation 具有细胞增殖的延迟HCV动力学模型的全局稳定性
Q4 MATHEMATICS, APPLIED Pub Date : 2022-09-10 DOI: 10.5206/mase/14918
Alexis Nangue, Armel Willy Fokam Tacteu, Ayouba Guedlai
In this work, we propose and investigate a delay cell population model of hepatitis C virus (HCV) infection with cellular proliferation, absorption effect and a nonlinear incidence function. First of all, after having shown the existence of the local solutions of our model, we show the existence of the global solutions and positivity. Moreover, we determine the uninfected equilibrium point and the basic reproduction rate R0, which is a threshold number in mathematical epidemiology. After showing the existence and uniqueness of the infected equilibrium point, we proceed to the study of the local and global stability of this equilibrium. We show that if  R0 < 1, the uninfected equilibrium point is globally asymptotically stable, which means that the disease will disappear and if  R0 > 1, we have a unique infected equilibrium that is globally asymptotically stable under some conditions. Finally, we perform some numerical simulations to illustrate the obtained theoretical results.
在这项工作中,我们提出并研究了一个具有细胞增殖、吸收效应和非线性发病函数的丙型肝炎病毒(HCV)感染的延迟细胞群模型。首先,在展示了我们模型的局部解的存在性之后,我们展示了全局解和正性的存在性。此外,我们确定了未感染的平衡点和基本繁殖率R0,这是数学流行病学中的阈值。在证明了受感染平衡点的存在性和唯一性之后,我们开始研究该平衡点的局部和全局稳定性。我们证明,如果R0<1,未感染的平衡点是全局渐近稳定的,这意味着疾病将消失;如果R0>1,我们有一个唯一的感染平衡点,在某些条件下是全局渐进稳定的。最后,我们进行了一些数值模拟来说明所获得的理论结果。
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引用次数: 1
Macroscopic Analysis Of The Viscous-Diffusive Traffic Flow Model 粘性扩散交通流模型的宏观分析
Q4 MATHEMATICS, APPLIED Pub Date : 2022-07-09 DOI: 10.5206/mase/14626
Gabriel Obed Fosu, A. Adu-Sackey, J. Ackora-Prah
Second-order macroscopic traffic models are characterized by a continuity equation and an acceleration equation. Convection, anticipation, relaxation, diffusion, and viscosity are the predominant features of the different classes of the acceleration equation. As a unique approach, this paper presents a new macro-model that accounts for all these dynamic speed quantities. This is done to determine the collective role of these traffic quantities in macroscopic modeling. The proposed model is solved numerically to explain some phenomena of a multilane traffic flow.  It also includes a linear stability analysis. Furthermore, the evolution of speed and density wave profiles are presented under the perturbation of some parameters.
二阶宏观交通模型由连续性方程和加速度方程表征。对流、预期、松弛、扩散和粘性是不同类别加速度方程的主要特征。作为一种独特的方法,本文提出了一种新的宏观模型,该模型考虑了所有这些动态速度量。这样做是为了确定这些交通量在宏观建模中的集体作用。对所提出的模型进行了数值求解,以解释多车道交通流的一些现象。它还包括线性稳定性分析。此外,还给出了在某些参数扰动下速度和密度波剖面的演化过程。
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引用次数: 0
A mathematical model of quorum quenching in biofilm colonies and its potential role as an adjuvant for antibiotic treatment 生物膜菌落群体猝灭的数学模型及其作为抗生素治疗辅助剂的潜在作用
Q4 MATHEMATICS, APPLIED Pub Date : 2022-06-16 DOI: 10.5206/mase/14612
M. Ghasemi, Viktoria Freingruber, C. Kuttler, H. Eberl
We extend a previously presented mesoscopic (i.e. colony scale) mathematical model of the reaction of bacterial biofilms to antibiotics. In that earlier model, exposure to antibiotics evokes two responses: inactivation as the antibiotics kill the bacteria, and inducing a quorum sensing based stress response mechanism upon exposure to small sublethal dosages. To this model we add now quorum quenching as an adjuvant to antibiotic therapy. Quorum quenchers are modeled like enzymes that degrade the quorum sensing signal concentration. The resulting model is a quasilinear system of seven reaction-diffusion equations for the dependent variables volume fractions of upregulated (protected), downregulated (unprotected) and inert (inactive) biomass [particulate substances], and for concentrations of a growth promoting nutrient, antibiotics, quorum sensing signal, and quorum quenchers [dissolved substances]. The biomass fractions are subject to two nonlinear diffusion effects: (i) degeneracy, as in the porous medium equation, where biomass vanishes, and (ii) a super-diffusion singularity where as it attains its theoretically possible maximum. We study this model in numerical simulations. Our simulations suggest that for maximum efficacy quorum quenchers should be applied early on before quorum sensing induction in the biofilm can take place, and that an antibiotic strategy that by itself might not be successful can be notably improved upon if paired with quorum quenchers as an adjuvant. 
我们扩展了先前提出的细菌生物膜对抗生素反应的介观(即菌落尺度)数学模型。在早期的模型中,暴露于抗生素会引起两种反应:抗生素杀死细菌时的失活,以及暴露于小剂量亚致死剂量时诱导基于群体感应的应激反应机制。在这个模型中,我们现在添加quorum淬火作为抗生素治疗的辅助剂。群体猝灭器的模型类似于降低群体感应信号浓度的酶。由此产生的模型是一个由七个反应扩散方程组成的拟线性系统,这些方程是关于上调(受保护)、下调(不受保护)和惰性(不活跃)生物质[颗粒物质]的因变量体积分数,以及促进生长的营养物、抗生素、群体感应信号和群体猝灭剂[溶解物质]的浓度。生物质组分受到两种非线性扩散效应的影响:(i)简并,如在多孔介质方程中,生物质消失;(ii)超扩散奇点,当它达到理论上可能的最大值时。我们对该模型进行了数值模拟研究。我们的模拟表明,为了获得最大的效果,群体猝灭剂应该在生物膜中群体感应诱导发生之前尽早应用,并且如果将群体猝灭剂作为佐剂配对,则抗生素策略本身可能不成功,可以显着改善。
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引用次数: 0
Global Analysis of a generalized viral infection temporal model with cell-to-cell transmission and absorption effect under therapy 治疗下具有细胞间传播和吸收效应的广义病毒感染时间模型的全局分析
Q4 MATHEMATICS, APPLIED Pub Date : 2022-05-15 DOI: 10.5206/mase/14663
Alexis Nangue, Paulin Tiomo Lemofouet, Simon Ndouvatama, Kengne Emmanuel
In virus dynamics, when a cell is infected, the number of virions outside the cells is reduced by one: this phenomenon is known as absorption effect. Most mathematical in vivo models neglect this phenomenon. Virus-to-cell infection and direct cell-to-cell transmission are two fundamental modes whereby viruses can be propagated and transmitted.  In this work, we propose a new virus dynamics model, which incorporates both modes and takes into account the absorption effect and treatment. First we show mathematically and biologically the well-posedness of our model preceded by the result on the existence and the uniqueness of the solutions. Also, an explicit formula for the basic reproduction number R0 of the model is determined. By analyzing the characteristic equations we establish the local stability of the uninfected equilibrium and the infected equilibrium in terms of R0. The global behavior of the model is investigated by constructing an appropriate Lyapunov functional for uninfected equilibrium and by applying a geometric approach to the study of the infected equilibrium. Numerical simulations are carried out, to confirm the obtained theoretical result in a particular case.
在病毒动力学中,当一个细胞被感染时,细胞外的病毒粒子数量减少一个:这种现象被称为吸收效应。大多数体内数学模型都忽略了这一现象。病毒-细胞感染和直接细胞-细胞传播是病毒繁殖和传播的两种基本方式。在这项工作中,我们提出了一个新的病毒动力学模型,它结合了这两种模式,并考虑了吸收效应和治疗。首先,我们从数学和生物学上证明了模型的适定性,然后给出了解的存在性和唯一性。并给出了模型基本再现数R0的显式公式。通过对特征方程的分析,建立了以R0表示的未感染平衡点和感染平衡点的局部稳定性。通过构造一个适当的Lyapunov泛函来研究模型的全局行为,并应用几何方法来研究感染平衡。通过数值模拟验证了所得到的理论结果。
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引用次数: 1
Modeling road surface potholes within the macroscopic flow framework 在宏观流动框架下对路面凹坑进行建模
Q4 MATHEMATICS, APPLIED Pub Date : 2022-05-15 DOI: 10.5206/mase/14625
Gabriel Obed Fosu, J. Opong, B. E. Owusu, S. Naandam
The continual wearing of road surfaces results to crack and holes called potholes. These road surface irregularities often elongate travel time. In this paper, a second-order macroscopic traffic model is therefore proposed to account for these road surface irregularities that affect the smooth flow of vehicular traffic. Though potholes do vary in shape and size, for simplicity the paper assumes that all potholes have conic resemblances. The impact of different sized potholes on driving is experimented using fundamental diagrams. Besides, the width of these holes, driver reaction time amid these irregularities also determine the intensity of the flow rate and vehicular speed. Moreover, a local cluster analysis is performed to determine the effect of a small disturbance on flow. The results revealed that the magnitude of amplification on a road surface with larger cracks is not as severe as roads with smaller size holes, except at minimal and jam density where all amplifications quickly fade out.
路面的持续磨损导致裂缝和洞称为坑洞。这些凹凸不平的路面常常延长旅行时间。因此,本文提出了一个二阶宏观交通模型来解释这些影响车辆交通顺畅的路面不规则性。虽然坑洞的形状和大小各不相同,但为了简单起见,本文假设所有坑洞都具有圆锥相似性。用基本图试验了不同大小的坑穴对行车的影响。此外,这些孔洞的宽度和驾驶员在这些不规则情况下的反应时间也决定了流量的强度和车辆的速度。此外,还进行了局部聚类分析,以确定小扰动对流动的影响。结果表明,裂缝较大的路面上的放大幅度不如孔洞较小的路面严重,但在最小和堵塞密度下,所有放大都迅速消退。
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引用次数: 1
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Mathematics in applied sciences and engineering
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