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On Behavioral Response of Ciliated Cervical Canal on the Development of Electroosmotic Forces in Spermatic Fluid 宫颈管对精子液电渗力发展的行为反应
IF 2.2 4区 数学 Q2 MATHEMATICAL & COMPUTATIONAL BIOLOGY Pub Date : 2022-07-21 DOI: 10.1051/mmnp/2022030
S. Abdelsalam, A. Z. Zaher
The goal of this research is to conduct a theoretical investigation about the effect of the electroosmotic forces on the swimming of sperms throughout the cervical canal. To imitate male semen with self-propulsive spermatozoa, a hyperbolic tangent fluid is used as the base liquid. Swimming sperms move inside a ciliated cervical canal and peristalsis occurs due to the ciliated walls. The perturbation method is used to solve the controlling partial differential set of equations analytically. Due to self-propulsion of swimmers and long wavelength assumption, a creeping flow protocol is used throughout the stream. The stream pattern, velocity distribution, and pressure gradient (above and below the swimming sheet) solutions are produced and displayed with the relevant parameters. The outcomes of this manuscript show that the rheological parameters of hyperbolic tangent fluid are more appropriate to simulate and discuss the motility of cervical fluid. Moreover, the motility of mucus velocity is more applicable for small values of power law index n at the upper swimming sheet of propulsive spermatozoa. In addition, the mucus velocity increases in both region (upper and lower region of swimming sheet) with an increase of the electroosmotic parameter  and Helmholtz-Smoluchowski velocity .
本研究的目的是对电渗力对精子在整个宫颈管中游动的影响进行理论研究。为了模仿具有自推进精子的男性精液,使用双曲正切流体作为基础液体。游动的精子在有纤毛的宫颈管内移动,蠕动是由于有纤毛的壁而发生的。用摄动方法解析求解控制偏微分方程组。由于游泳者的自我推进和长波假设,整个溪流都采用了爬行流协议。流模式、速度分布和压力梯度(游泳板上方和下方)解决方案将与相关参数一起生成和显示。本文的结果表明,双曲正切流体的流变参数更适合于模拟和讨论宫颈液的运动。此外,粘液速度的运动性更适用于推进精子上层的幂律指数n值较小的情况。此外,随着电渗参数和Helmholtz-Smoluchowski速度的增加,两个区域(游泳板的上部和下部区域)的粘液速度都会增加。
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引用次数: 39
Nonlocal longitudinal vibration in a nanorod, a system theoretic analysis 纳米棒非局部纵向振动的系统理论分析
IF 2.2 4区 数学 Q2 MATHEMATICAL & COMPUTATIONAL BIOLOGY Pub Date : 2022-07-13 DOI: 10.1051/mmnp/2022028
Hanif Heidari, H. Zwart
Analysis of longitudinal vibration in a nanorod is an important subject in science and engineering due to its vast application in nanotechnology. This paper introduces a port-Hamiltonian formulation for the longitudinal vibrations in a nanorod, which shows that this model is essentially hyperbolic. Furthermore, it investigates the spectral properties of the associated system operator. Standard distributed control and feedback are shown not to be controllable nor stabilizing.
纳米棒的纵向振动分析由于其在纳米技术中的广泛应用而成为科学和工程中的一个重要课题。本文介绍了纳米棒纵向振动的端口哈密顿公式,表明该模型本质上是双曲型的。此外,它还研究了相关系统算子的谱性质。标准的分布式控制和反馈被证明既不可控也不稳定。
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引用次数: 1
A SIQRB delayed model for cholera and optimal control treatment 霍乱SIQRB延迟模型及其最优控制治疗
IF 2.2 4区 数学 Q2 MATHEMATICAL & COMPUTATIONAL BIOLOGY Pub Date : 2022-06-25 DOI: 10.1051/mmnp/2022027
Ana P. Lemos-Paião, H. Maurer, Cristiana J. Silva, Delfim F. M. Torres
We improve a recent mathematical model for cholera by adding a time delay that represents the time between the instant at which an individual becomes infected and the instant at which he begins to have symptoms of cholera disease. We prove that the delayed cholera model is biologically meaningful and analyze the local asymptotic stability of the equilibrium points for positive time delays. An optimal control problem is proposed and analyzed, where the goal is to obtain optimal treatment strategies, through quarantine, that minimize the number of infective individuals and the bacterial concentration, as well as treatment costs. Necessary optimality conditions are applied to the delayed optimal control problem, with a $L^1$ type cost functional. We show that the delayed cholera model fits better the cholera outbreak that occurred in the Department of Artibonite -- Haiti, from 1 November 2010 to 1 May 2011, than the non delayed model. Considering the data of the cholera outbreak in Haiti, we solve numerically the delayed optimal control problem and propose solutions for the outbreak control and eradication.
我们改进了最近的霍乱数学模型,增加了一个时间延迟,该时间延迟表示一个人被感染的时刻和他开始出现霍乱症状的时刻之间的时间。我们证明了延迟霍乱模型具有生物学意义,并分析了正时滞平衡点的局部渐近稳定性。提出并分析了一个最优控制问题,其目标是通过隔离获得最优治疗策略,以最大限度地减少感染个体的数量、细菌浓度以及治疗成本。将必要的最优性条件应用于具有$L^1$型成本函数的延迟最优控制问题。我们表明,与非延迟模型相比,延迟霍乱模型更适合2010年11月1日至2011年5月1日发生在海地阿蒂博尼特省的霍乱疫情。考虑到海地霍乱疫情的数据,我们对延迟最优控制问题进行了数值求解,并提出了控制和根除霍乱疫情的解决方案。
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引用次数: 4
Wave blocking in a bistable system by local introduction of a population~: application to sterile insect techniques on mosquito populationsp, li { white-space: pre-wrap; } 局部引入种群在双稳态系统中的波阻挡作用:在蚊虫种群不育昆虫技术中的应用[j], [j]}
IF 2.2 4区 数学 Q2 MATHEMATICAL & COMPUTATIONAL BIOLOGY Pub Date : 2022-06-16 DOI: 10.1051/mmnp/2022026
L. Almeida, J. Estrada, N. Vauchelet
The Sterile Insect Technique (SIT) is a classic vector control method that has been successfully applied to fight against diverse insect plagues since the 1950s . In recent years, this strategy has been used to control mosquito populations, in order to limit the spread of the diseases they transmit. In this paper, we consider a system of reaction-diffusion equations to model the mosquito population and study the effect of the release of sterile mosquito males. Then we propose to analyze the release in a limited area inside a wider area containing natural mosquito population. We are interested in protecting a mosquito free region from invasion by mosquitoes from an exterior domain by controlling the population in a release band at the border between the two regions: we construct a barrier blocking the invasion of mosquitoes from the exterior. We adapt the geometric method of Lewis and Keener in this framework and extend their main result to find relations on the size of the release region and the density of the released sterile males that allow us to block the invasion. Numerical simulations are also performed to illustrate our results.
昆虫不育技术(SIT)是一种经典的媒介控制方法,自20世纪50年代以来已成功应用于对抗各种昆虫瘟疫。近年来,这一策略已被用于控制蚊子的数量,以限制它们传播的疾病的传播。在本文中,我们考虑了一个反应扩散方程组来模拟蚊子种群,并研究了释放不育雄蚊的影响。然后,我们建议在包含自然蚊子种群的更大区域内,分析有限区域内的释放。我们感兴趣的是通过控制两个地区边界释放带中的种群来保护无蚊区免受外部蚊子的入侵:我们建造了一个屏障,阻止蚊子从外部入侵。我们在这个框架中采用了Lewis和Keener的几何方法,并扩展了他们的主要结果,以找到释放区域的大小和释放的不育雄性的密度之间的关系,从而使我们能够阻止入侵。还进行了数值模拟来说明我们的结果。
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引用次数: 3
The effect of composite material on Rayleigh wave at free surface of composite matrix saturated by fluids. 复合材料对流体饱和复合材料自由表面瑞利波的影响。
IF 2.2 4区 数学 Q2 MATHEMATICAL & COMPUTATIONAL BIOLOGY Pub Date : 2022-06-10 DOI: 10.1051/mmnp/2022025
A. Arora, N. Bala
The present study signifies the effect of distinct solids on the phase speed and attenuation of Rayleigh surface wave propagating on the boundary of composite porous matrix saturated with fluids. Secular equation depicting propagation of Rayleigh wave is obtained and solved numerically for obtaining phase speed and attenuation coefficient. Two different types of composite materials are considered for numerical study to analyze the effect of solids present in the structure. The study depicts that increase in rigidity of the composite increases the phase speed of the Rayleigh surface wave. Significant effect of the density and bulk modulus of fluid mixture present in the pores is also observed on the phase speed of the wave. The effect of porosity on the phase speed of the Rayleigh wave and the particle motion during the propagation of the wave is also analyzed.
本文研究了不同固体对流体饱和复合多孔基质边界上瑞利面波传播相速度和衰减的影响。得到瑞利波传播的长期方程,并对其进行数值求解,得到相速和衰减系数。采用两种不同类型的复合材料进行数值研究,以分析结构中固体的影响。研究表明,复合材料刚度的增加增加了瑞利表面波的相速度。孔隙中流体混合物的密度和体积模量对波的相速也有显著影响。本文还分析了孔隙率对瑞利波相速度和粒子运动的影响。
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引用次数: 0
Rational choice of modelling assumptions for simulation of blood vessel end-to-side anastomosis 血管端侧吻合仿真模型假设的合理选择
IF 2.2 4区 数学 Q2 MATHEMATICAL & COMPUTATIONAL BIOLOGY Pub Date : 2022-06-08 DOI: 10.1051/mmnp/2022022
I. I. Tagiltsev, D. Parshin, A. Shutov
Blood vessels exhibit highly nonlinear, anisotropic behaviour with numerous mechanical interactions. Since exact modelling of all involved effects would yield a computationally prohibitive procedure, a practical clinical simulation tool needs to account for a minimum threshold of relevant factors. In this study, we analyse needed modelling assumptions for a reliable simulation of the end-to-side anastomosis. The artery wall is modelled in a geometrically exact setting as a pre-stressed fibre-reinforced composite. The study focuses on the sensitivity analysis of post-anastomosis stress fields concerning the modelling assumptions. Toward that end, a set of full-scale finite element simulations is carried out for three sensitivity cases: (i) The post-operational stresses are estimated with and without taking the residual stresses into account. (ii) Different geometries of the cut in the recipient vessel are examined. (iii) The influence of errors in material stiffness identification on the post-operational stress field is estimated. The studied cases (i)---(iii) have shown a substantial impact of the considered modelling assumptions on the predictive capabilities of the simulation. Approaches to more accurate predictions of post-operational stress distribution are outlined, and a quest for more accurate experimental procedures is made. As a by-product, the occurrence of the pseudo-aneurysm is explained.
血管表现出高度非线性、各向异性的行为,具有许多机械相互作用。由于所有相关影响的精确建模将产生计算上令人望而却步的程序,因此实用的临床模拟工具需要考虑相关因素的最小阈值。在这项研究中,我们分析了端侧吻合可靠模拟所需的建模假设。动脉壁在几何精确的设置中建模为预应力纤维增强复合材料。本研究的重点是与建模假设相关的吻合后应力场的敏感性分析。为此,对三种敏感情况进行了一组全尺寸有限元模拟:(i)在考虑和不考虑残余应力的情况下估计操作后的应力。(ii)检查受体血管中切口的不同几何形状。(iii)估计了材料刚度识别中的误差对操作后应力场的影响。所研究的案例(i)-(iii)表明,所考虑的建模假设对模拟的预测能力产生了重大影响。概述了更准确地预测操作后应力分布的方法,并寻求更准确的实验程序。作为副产品,对假性动脉瘤的发生进行了解释。
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引用次数: 3
Mathematical Modelling of Natural Phenomena 自然现象的数学模型
IF 2.2 4区 数学 Q2 MATHEMATICAL & COMPUTATIONAL BIOLOGY Pub Date : 2022-05-24 DOI: 10.1051/mmnp/2022021
M. Adimy, Abdennasser Chekroun, B. Kazmierczak
Abstract.   We consider a class of biological models represented by a system composed of reaction-diffusion PDE coupled with difference equations (renewal equations) in $n$-dimensional space, with nonlocal dispersal terms and implicit time delays. The difference equation generally arises, by means of the method of characteristics, from an age-structured partial differential system. Using upper and lower solutions, we study the existence of monotonic planar traveling wave fronts connecting the extinction state to the uniform positive state. The corresponding minimum wave speed is also obtained. In addition, we investigate the effect of the parameters on this minimum wave speed and we give a detailed analysis of its asymptotic behavior.
摘要我们考虑了一类由反应扩散PDE和差分方程(更新方程)组成的系统表示的生物模型,该系统在$n$-维空间中具有非局部扩散项和隐式时滞。差分方程通常通过特征法由年龄结构的偏微分系统产生。利用上下解,我们研究了连接消光态和均匀正态的单调平面行波阵面的存在性。还获得了相应的最小波速。此外,我们还研究了参数对该最小波速的影响,并对其渐近行为进行了详细分析。
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引用次数: 0
Structural changes of a radially symmetric thermocapillary flow in the shallow cavity partially covered by a solid film 部分被固体膜覆盖的浅腔中径向对称热毛细流的结构变化
IF 2.2 4区 数学 Q2 MATHEMATICAL & COMPUTATIONAL BIOLOGY Pub Date : 2022-05-18 DOI: 10.1051/mmnp/2022019
V. Demin, M. Petukhov
Numerical study is devoted to the spatial transformations of a radially symmetric flow in the liquid, filling a shallow cylindrical cavity covered partially by a solid non-deformable film. The upper part of liquid has a free surface in the center of which a beam of light produces the hot dot. The heating generates a divergent thermocapillary motion along the free surface after that the liquid flows under the immovable solid film. The edge of this film induces the perturbations into the current. At definite values of heat generation these perturbations begin to increase and cause the radial flow symmetry breakdown that visually leads to the origin of the vorticity in azimuthal plane. Three-dimensional calculations have been fulfilled on the base of interfacial hydrodynamics equations using mathematical package “Comsol Multiphysics”. The motion in azimuthal direction becomes more evident with the growth of heating intensity. There is a predominantly radial flow in the region with the free surface. At the same time, the vortices with azimuthal component of velocity are observed under the film. As in experiment, the proportion of free surface area to the covered one determines the number of vortices in azimuthal plane.
数值研究了液体中径向对称流的空间变换,该流填充在部分被固体不可变形膜覆盖的浅圆柱形腔中。液体的上部有一个自由表面,在其中心有一束光产生热点。加热产生沿自由表面发散的热毛细运动,之后液体在不可移动的固体膜下流动。薄膜的边缘将微扰引入电流。在一定的产热值时,这些扰动开始增加,并导致径向流动对称性的破坏,这在视觉上导致了方位面涡度的起源。利用Comsol Multiphysics数学包,在界面流体力学方程的基础上进行了三维计算。随着加热强度的增大,在方位方向上的运动更加明显。在有自由表面的区域,主要是径向流动。同时,在膜下观察到具有速度方位分量的涡旋。在实验中,自由表面积与被覆盖表面积的比例决定了方位面中漩涡的数量。
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引用次数: 0
Mathematical modelling of proton migration in Earth mantle 地幔中质子迁移的数学模型
IF 2.2 4区 数学 Q2 MATHEMATICAL & COMPUTATIONAL BIOLOGY Pub Date : 2022-05-17 DOI: 10.1051/mmnp/2022018
V. Bobrovskiy, J. Galvis, A. Kaplin, A. Sinitsyn, Marco Tognoli, P. Trucco
In the study, we address the mathematical problem of proton migration in the Earth’smantle and suggest a prototype for exploring the Earth’s interior to map the effects of superionicproton conduction. The problem can be mathematically solved by deriving the self-consistent electromagnetic field potential U(x,t) and then reconstructing the distribution function f(x, v, t). Reducing the Vlasov-Maxwell system of equations to non-linear sh-Gordon hyperbolic and transport equations, the propagation of a non-linear wavefront within the domain and transport of the boundary conditions in the form of a non-linear wave are examined. By computing a 3D model and through Fourier-analysis, the spatial and electrical characteristics of potential U(x, t) are investigated. The numerical results are compared to the Fourier transformed quantities of the potential (V) obtained through field observations of the electric potential (Kuznetsov method). The non-stationary solutions for the forced oscillation of two-component system, and therefore, the oscillatory strengths of two types of charged particles can be usefully addressed by the proposed mathematical model. Moreover, the model, along with data analysis of the electric potential observations and probabilistic seismic hazard maps, can be used to develop an advanced seismic risk metric.
在这项研究中,我们解决了地球地幔中质子迁移的数学问题,并提出了一个用于探索地球内部以绘制超电子质子传导效应的原型。通过推导自洽电磁场势U(x,t),然后重构分布函数f(x, v, t),可以在数学上解决该问题。将Vlasov-Maxwell方程组简化为非线性sh-Gordon双曲方程和输运方程,研究了非线性波前在域内的传播和边界条件以非线性波形式的输运。通过计算三维模型和傅里叶分析,研究了电位U(x, t)的空间和电特性。数值结果与通过电势场观测(库兹涅佐夫法)得到的电位(V)的傅里叶变换量进行了比较。该数学模型可以有效地求解双组分系统强迫振荡的非平稳解,从而求解两种带电粒子的振荡强度。此外,该模型与电势观测数据分析和概率地震危险度图一起,可用于开发先进的地震风险度量。
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引用次数: 1
Efficient Uncertainty Quantification and Variance-Based Sensitivity Analysis in Epidemic Modelling using Polynomial Chaos 基于多项式混沌的流行病模型的有效不确定性量化和方差敏感性分析
IF 2.2 4区 数学 Q2 MATHEMATICAL & COMPUTATIONAL BIOLOGY Pub Date : 2022-04-25 DOI: 10.1051/mmnp/2022014
Bjørn Jensen, A. Engsig-Karup, Kim Knudsen
The use of epidemic modelling in connection with spread of diseases plays an important role in understanding dynamics and providing forecasts for informed analysis and decision-making. In this regard, it is crucial to quantify the effects of uncertainty in the modelling and in model-based predictions to trustfully communicate results and limitations. We propose to do efficient uncertainty quantification in compartmental epidemic models using the generalized Polynomial Chaos (gPC) framework. This framework uses a suitable polynomial basis that can be tailored to the underlying distribution for the parameter uncertainty to do forward propagation through efficient sampling via a mathematical model to quantify the effect on the output. By evaluating the model in a small number of selected points, gPC  provides illuminating statistics and sensitivity analysis at a low computational cost. Through two particular case studies based on Danish data for the spread of Covid-19, we demonstrate the applicability of the technique. The test cases consider epidemic peak time estimation and the dynamics between superspreading and partial lockdown measures. The computational results show the efficiency and  feasibility of the uncertainty quantification techniques based on gPC, and highlight the relevance of computational uncertainty quantification in epidemic modelling.
将流行病建模用于疾病传播在了解动态和为知情分析和决策提供预测方面发挥着重要作用。在这方面,至关重要的是量化建模和基于模型的预测中的不确定性影响,以可靠地传达结果和局限性。我们建议使用广义多项式混沌(gPC)框架在分区流行病模型中进行有效的不确定性量化。该框架使用合适的多项式基,该多项式基可以根据参数不确定性的基本分布进行调整,通过数学模型通过有效采样进行正向传播,以量化对输出的影响。通过在少量选点中评估模型,gPC以较低的计算成本提供了启发性的统计和灵敏度分析。通过基于丹麦新冠肺炎传播数据的两个特定案例研究,我们证明了该技术的适用性。测试案例考虑了疫情高峰时间估计以及超级传播和部分封锁措施之间的动态。计算结果表明了基于gPC的不确定性量化技术的有效性和可行性,并强调了计算不确定性量化在流行病建模中的相关性。
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引用次数: 2
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Mathematical Modelling of Natural Phenomena
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