Stability analysis

稳定性分析
  • 文章类型: Journal Article
    宫颈癌是最常见的癌症类型之一,它主要由高风险的人乳头瘤病毒(HPV)引起,并继续以惊人的速度传播。虽然HPV的影响之前已经调查过,目前只有少量的数学模型来说明HPV在宫颈癌中的动态作用.目标是开发一个宿主内密度依赖性确定性模型,用于基底细胞的动力学含义。病毒体,和结合免疫和功能反应的淋巴细胞。使用基本复制数等流行病学模型技术对模型进行分析,并使用MatlabODE求解器对模型进行仿真。在模型中考虑了六个区室;易感细胞(S),感染细胞(I),癌前细胞(P),癌细胞(C),病毒体(V),和淋巴细胞(L)。下一代矩阵(NGM),生存功能,和特征多项式方法用于确定表示为R0的基本再现数。R0是使用三种方法获得的,因为NGM有一些弱点,因此需要其他两种方法。这项研究的结果表明,当R0*<1时,无疾病平衡点是局部渐近稳定的,如果R0*≤1,则局部渐近稳定,如果R0*>1,则局部平衡是全局渐近稳定的。获得的结果表明,癌前细胞向癌细胞的进展速率(θ)对模型具有最直接的影响。当(θ)增加0.08时,该模型能够将患者的寿命估计为10天。这项研究的结果将有助于医疗保健提供者,公共卫生当局,和非政府健康团体制定有效的预防策略来减缓宫颈癌的发展。应该做更多的研究来确定可能导致宫颈癌患者死亡的癌细胞的确切数量,因为本文估计比例为75%。
    Cervical cancer is one of the most common types of cancer and it is caused mostly by high-risk Human Papillomavirus (HPV) and continues to spread at an alarming rate. While HPV impacts have been investigated before, there are currently only a scanty number of mathematical models that account for HPV\'s dynamic role in cervical cancer. The objectives were to develop an in-host density-dependent deterministic model for the dynamics implications of basal cells, virions, and lymphocytes incorporating immunity and functional responses. Analyze the model using techniques of epidemiological models such as basic reproduction number and simulate the model using Matlab ODE solver. Six compartments are considered in the model that is; Susceptible cells (S), Infected cells (I), Precancerous cells (P), Cancerous cells (C), Virions (V), and Lymphocytes (L). Next generation matrix (NGM), survival function, and characteristic polynomial method were used to determine the basic reproduction number denoted as R 0 . R 0 was obtained using three methods because NGM has some weaknesses hence the need for the other two methods. The findings from this research indicated that Disease-Free Equilibrium point is locally asymptotically stable whenever R 0 * < 1 and globally asymptotically stable if R 0 * ≤ 1 and the Endemic Equilibrium is globally asymptotically stable if R 0 * > 1 . The results obtained shows that the progression rate of precancerous cells to cancerous cells ( θ ) has the most direct impact on the model. The model was able to estimate the longevity of a patient as 10 days when ( θ ) increases by 0.08 . The findings of this research will help healthcare providers, public health authorities, and non-governmental health groups in creating effective prevention strategies to slow the development of cervical cancer. More research should be done to determine the exact number of cancerous cells that can lead to the death of a cervical cancer patient since this paper estimated a proportion of 75 % .
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  • 文章类型: Journal Article
    在目前的研究中,我们采用Atangana-Baleanu意义上的新型分形分数算子来研究相互作用浮游植物物种模型的动力学。最初,我们利用Picard-Lindelöf定理来验证模型解的唯一性和存在性。然后,我们探索浮游植物模型中的平衡点,并进行Hyers-Ulam稳定性分析。此外,我们提出了一个利用牛顿多项式的数值方案来验证我们的分析结果。数值模拟说明了模型在各种分形和分数参数值上的动力学行为,通过图形表示可视化。我们的模拟表明,平衡点的稳定性不受长期记忆效应的影响。其特征在于分形分数阶值。然而,分形分数参数的增加加速了解收敛到其预期平衡状态。
    In the current study, we employ the novel fractal-fractional operator in the Atangana-Baleanu sense to investigate the dynamics of an interacting phytoplankton species model. Initially, we utilize the Picard-Lindelöf theorem to validate the uniqueness and existence of solutions for the model. We then explore equilibrium points within the phytoplankton model and conduct Hyers-Ulam stability analysis. Additionally, we present a numerical scheme utilizing the Newton polynomial to validate our analytical findings. Numerical simulations illustrate the dynamical behavior of the model across various fractal and fractional parameter values, visualized through graphical representations. Our simulations reveal that the stability of equilibrium points is not significantly impacted with the long-term memory effect, which is characterized by fractal-fractional order values. However, an increase in fractal-fractional parameters accelerates the convergence of solutions to their intended equilibrium states.
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  • 文章类型: Journal Article
    COVID-19大流行带来了许多挫折,无论是对一个国家的经济还是像世界卫生组织这样的组织的全球使命,儿童基金会或GTFCC。挫折之一是由于缺乏霍乱疫苗接种,发展中国家霍乱病例增加。该模型通过引入另一种公共干预提出了解决方案,例如在水体中添加氯和接种疫苗。提出了一种新的分数阶时滞微分模型,有两种不同的延迟,一个代表疾病的潜伏期,另一个代表向水生环境添加消毒剂的延迟。该模型还考虑了将接受疫苗接种的人群。本研究利用繁殖数量的敏感性分析来分析证明控制措施在预防疾病传播方面的有效性。该分析为在水体中添加消毒剂和接种易感个体提供了数学证据。已经讨论了平衡点的稳定性。确定了稳定性切换曲线的存在性。数值模拟显示了延迟的影响,导致一些隔间的波动。它还描述了导数阶数对振荡的影响。
    The COVID-19 pandemic came with many setbacks, be it to a country\'s economy or the global missions of organizations like WHO, UNICEF or GTFCC. One of the setbacks is the rise in cholera cases in developing countries due to the lack of cholera vaccination. This model suggested a solution by introducing another public intervention, such as adding Chlorine to water bodies and vaccination. A novel delay differential model of fractional order was recommended, with two different delays, one representing the latent period of the disease and the other being the delay in adding a disinfectant to the aquatic environment. This model also takes into account the population that will receive a vaccination. This study utilized sensitivity analysis of reproduction number to analytically prove the effectiveness of control measures in preventing the spread of the disease. This analysis provided the mathematical evidence for adding disinfectants in water bodies and inoculating susceptible individuals. The stability of the equilibrium points has been discussed. The existence of stability switching curves is determined. Numerical simulation showed the effect of delay, resulting in fluctuations in some compartments. It also depicted the impact of the order of derivative on the oscillations.
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  • 文章类型: Journal Article
    从(21)维旋转黑洞构造薄壳虫洞的动机源于研究该特定时空中非最小耦合标量场的影响的愿望。通过研究这种场在存在旋转的情况下的行为,我们可以深入了解低维系统中重力场和标量场之间的相互作用。此外,这种构造使我们能够探索黑洞物理学与可穿越虫洞等奇异现象之间的潜在联系。考虑围绕平衡喉部半径的径向扰动,以探索物理参数特定值的稳定配置。然后,状态方程,特别是用于外来物质的类幻影和广义Chaplygin气体模型,用于对反向旋转的薄壳虫孔的稳定性进行广泛研究。我们的结果表明,标量场的存在增强了反向旋转的薄壳虫洞的稳定性。
    The motivation for constructing a thin-shell wormhole from a (2+1)-dimensional rotating black hole arises from the desire to study the effects of a nonminimally coupled scalar field in this particular spacetime. By investigating the behavior of such a field in the presence of rotation, we can gain insights into the interplay between gravity and scalar fields in lower-dimensional systems. Additionally, this construction allows us to explore potential connections between black hole physics and exotic phenomena like traversable wormholes. The radial perturbation around the equilibrium throat radius is considered to explore the stable configuration for specific values of physical parameters. Then, the equations of state, specifically the phantom-like and generalized Chaplygin gas model for exotic matter is used to conduct an extensive investigation into the stability of the counter-rotating thin-shell wormholes. Our results show that the presence of a scalar field enhances the stability of the counter-rotating thin-shell wormholes.
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  • 文章类型: Journal Article
    这项研究引入了分数阶模型来研究脊髓灰质炎疾病传播的动态,专注于它的意义,独特的结果,和结论。我们强调了解脊髓灰质炎传播动力学的重要性,并提出了一种使用具有指数衰减核的分数阶模型的新颖方法。经过严格的分析,包括应用CaputoFabrizio分数阶算子的存在性和稳定性评估,我们得出了疾病动态的关键见解。我们的发现揭示了不同的无病平衡点(DFE)和地方性平衡点(EE),揭示疾病的稳定性。此外,图形表示和数值模拟证明了疾病在各种参数值下的行为,加强我们对脊髓灰质炎传播动态的理解。总之,这项研究为脊髓灰质炎的传播提供了有价值的见解,并有助于更广泛地了解传染病的动态。
    This study introduces a fractional order model to investigate the dynamics of polio disease spread, focusing on its significance, unique results, and conclusions. We emphasize the importance of understanding polio transmission dynamics and propose a novel approach using a fractional order model with an exponential decay kernel. Through rigorous analysis, including existence and stability assessment applying the Caputo Fabrizio fractional operator, we derive key insights into the disease dynamics. Our findings reveal distinct disease-free equilibrium (DFE) and endemic equilibrium (EE) points, shedding light on the disease\'s stability. Furthermore, graphical representations and numerical simulations demonstrate the behavior of the disease under various parameter values, enhancing our understanding of polio transmission dynamics. In conclusion, this study offers valuable insights into the spread of polio and contributes to the broader understanding of infectious disease dynamics.
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  • 文章类型: Journal Article
    本文论证了,一种数值方法,用于求解涉及具有非奇异核的时间分数Atangana-BaleanuCaputo(ABC)导数的一维和二维Burgers方程。数值策略由时间分数(ABC)导数的正交规则以及一维和二维问题的Haar小波(HW)近似组成。该方案的关键特征是通过搭配过程将分数问题简化为线性方程组。求解该系统给出了给定问题的近似解。为了验证所开发方法的有效性,考虑了五个数值示例。除此之外,将获得的模拟与一些已发表的工作进行比较,并确定提出的技术更好。此外,在计算上给出了时空方向的收敛速度,显示了二阶收敛。还通过Lax-Richtmyer准则描述了所提出方案的稳定性。从仿真中可以明显看出,该方案对于时间分数问题非常有用。
    This paper demonstrates, a numerical method to solve the one and two dimensional Burgers\' equation involving time fractional Atangana-Baleanu Caputo ( ABC ) derivative with a non-singular kernel. The numerical stratagem consists of a quadrature rule for time fractional ( ABC ) derivative along with Haar wavelet (HW) approximations of one and two dimensional problems. The key feature of the scheme is to reduce fractional problems to the set of linear equations via collocation procedure. Solving the system gives the approximate solution of the given problem. To verify the effectiveness of the developed method five numerical examples are considered. Besides this, the obtained simulations are compared with some published work and identified that proposed technique is better. Moreover, computationally the convergence rate in spatiotemporal directions is presented which shows order two convergence. The stability of the proposed scheme is also described via Lax-Richtmyer criterion. From simulations it is obvious that the scheme is quite useful for the time fractional problems.
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  • 文章类型: Journal Article
    滑翔运动的细胞形状几乎没有变化,通常是由于与细胞外环境结合的粘附素的主动驱动表面流动所致。它允许在表面或组织中快速移动,特别是对于来自顶孔门的真核寄生虫,其中包括广泛传播的疟疾和弓形虫病的病原体。我们开发了一个完全三维的活动粒子理论,它连接了自组织,在固定的细胞形状上主动驱动表面流动到最终的全局运动模式。我们的解析解和数值模拟表明,对于简单的形状,没有旋转的直线运动是不稳定的,并且笔直的细胞形状往往会导致纯旋转。这表明疟原虫子孢子和弓形虫速殖子的弯曲形状是进化适应,以避免旋转而不翻译。某些粘细菌或黄细菌也使用滑翔运动,主要在平坦的外表面上移动,并且对通过内部轨道的细胞表面流量有更高的控制。我们为这些案例扩展了我们的理论。我们再次发现旋转和平移之间的竞争,并预测内部轨道几何形状对整体前进速度的影响。虽然具体机制可能因物种而异,总的来说,我们的几何理论预测和解释了旋转,圆形,以及微滑翔机通常观察到的螺旋轨迹。我们的理论也可以用来设计合成的小滑翔机。
    Gliding motility proceeds with little changes in cell shape and often results from actively driven surface flows of adhesins binding to the extracellular environment. It allows for fast movement over surfaces or through tissue, especially for the eukaryotic parasites from the phylum apicomplexa, which includes the causative agents of the widespread diseases malaria and toxoplasmosis. We have developed a fully three-dimensional active particle theory which connects the self-organized, actively driven surface flow over a fixed cell shape to the resulting global motility patterns. Our analytical solutions and numerical simulations show that straight motion without rotation is unstable for simple shapes and that straight cell shapes tend to lead to pure rotations. This suggests that the curved shapes of Plasmodium sporozoites and Toxoplasma tachyzoites are evolutionary adaptations to avoid rotations without translation. Gliding motility is also used by certain myxo- or flavobacteria, which predominantly move on flat external surfaces and with higher control of cell surface flow through internal tracks. We extend our theory for these cases. We again find a competition between rotation and translation and predict the effect of internal track geometry on overall forward speed. While specific mechanisms might vary across species, in general, our geometrical theory predicts and explains the rotational, circular, and helical trajectories which are commonly observed for microgliders. Our theory could also be used to design synthetic microgliders.
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  • 文章类型: Journal Article
    为了理解社会中疾病传播的动态,数学公式是必不可少的。这项工作的目的是通过引入细胞因子(IL2&IL12)和抗PD-L1抑制剂来研究免疫系统减弱者肺癌的诊断和治疗。为了找到最近建立的系统TCDIL2IL12Z的稳定位置,在敏感参数下进行定性和定量分析。通过检查生成的系统的有界性来确保可靠的有界发现,积极性,独特性,和局部稳定性分析,这是流行病模型的关键特征。具有线性增长的正解被全局导数验证,使用Lipschitz标准确定每个子隔室的影响速率。使用具有一阶导数的Lyapunov函数,为了评估细胞因子和抗PD-L1抑制剂对免疫系统较弱的人的联合作用,检查了该系统的整体稳定性。通过使用Mittag-Leffler内核与分形分数算子相结合来实现可靠性,因为FFO以多维方式提供了对肺癌的连续监测。为了验证抗PD-L1抑制剂之间的关系,使用模拟研究肺癌疾病的症状和无症状效应。细胞因子,和免疫系统。此外,通过引入细胞因子和抗PD-L1抑制剂,通过早期诊断和治疗来确定肺癌控制的实际状态,这有助于患者产生抗癌细胞。根据我们验证的结果调查疾病的传播并创建控制方法都将从这种研究中受益。
    In order to comprehend the dynamics of disease propagation within a society, mathematical formulations are essential. The purpose of this work is to investigate the diagnosis and treatment of lung cancer in persons with weakened immune systems by introducing cytokines ( I L 2 & I L 12 ) and anti-PD-L1 inhibitors. To find the stable position of a recently built system TCD I L 2 I L 12 Z, a qualitative and quantitative analysis are taken under sensitive parameters. Reliable bounded findings are ensured by examining the generated system\'s boundedness, positivity, uniqueness, and local stability analysis, which are the crucial characteristics of epidemic models. The positive solutions with linear growth are shown to be verified by the global derivative, and the rate of impact across every sub-compartment is determined using Lipschitz criteria. Using Lyapunov functions with first derivative, the system\'s global stability is examined in order to evaluate the combined effects of cytokines and anti-PD-L1 inhibitors on people with weakened immune systems. Reliability is achieved by employing the Mittag-Leffler kernel in conjunction with a fractal-fractional operator because FFO provide continuous monitoring of lung cancer in multidimensional way. The symptomatic and asymptomatic effects of lung cancer sickness are investigated using simulations in order to validate the relationship between anti-PD-L1 inhibitors, cytokines, and the immune system. Also, identify the actual state of lung cancer control with early diagnosis and therapy by introducing cytokines and anti-PD-L1 inhibitors, which aid in the patients\' production of anti-cancer cells. Investigating the transmission of illness and creating control methods based on our validated results will both benefit from this kind of research.
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  • 文章类型: Journal Article
    疟疾是一种传染性和传染性疾病,由一种或多种疟原虫寄生虫引起。人类有五种寄生虫导致疟疾,其中两个,恶性疟原虫和间日疟原虫,是最危险的.在吉布提,两种疟原虫在感染人群中以不同的比例存在:77%的恶性疟原虫和33%的Vivax。在这项研究中,我们提出了一个新的数学模型,描述了恶性疟原虫和间日疟原虫共感染的时间动力学。我们简要地关注此模型的适当性以及每种疟原虫物种感染的基本生殖数的计算,这有助于我们了解此模型的长期动态(即,各种eqiuilibria的存在和稳定性)。然后我们使用计算方法:(a)使用吉布提疟疾感染的真实数据确定模型参数;(b)说明不同估计参数对基本繁殖数的影响;(c)对各种模型参数对传染性蚊子和受感染人类的瞬时动态的影响进行全局敏感性和不确定性分析,每个疟原虫物种的感染。这项研究的独创性源于采用FAST方法和LHS方法来确定影响吉布提人群疾病进展的关键因素。此外,敏感性分析确定了对镰刀菌和活鱼繁殖率影响最大的参数。最后,不确定性分析使我们能够了解感染区室某些参数的变异性.
    Malaria is an infectious and communicable disease, caused by one or more species of Plasmodium parasites. There are five species of parasites responsible for malaria in humans, of which two, Plasmodium Falciparum and Plasmodium Vivax, are the most dangerous. In Djibouti, the two species of Plasmodium are present in different proportions in the infected population: 77% of P. Falciparum and 33% of P. Vivax. In this study we present a new mathematical model describing the temporal dynamics of Plasmodium Falciparum and Plasmodium Vivax co-infection. We focus briefly on the well posedness of this model and on the calculation of the basic reproductive numbers for the infections with each Plasmodium species that help us understand the long-term dynamics of this model (i.e., existence and stability of various eqiuilibria). Then we use computational approaches to: (a) identify model parameters using real data on malaria infections in Djibouti; (b) illustrate the influence of different estimated parameters on the basic reproduction numbers; (c) perform global sensitivity and uncertainty analysis for the impact of various model parameters on the transient dynamics of infectious mosquitoes and infected humans, for infections with each of the Plasmodium species. The originality of this research stems from employing the FAST method and the LHS method to identify the key factors influencing the progression of the disease within the population of Djibouti. In addition, sensitivity analysis identified the most influential parameter for Falciparium and Vivax reproduction rates. Finally, the uncertainty analysis enabled us to understand the variability of certain parameters on the infected compartments.
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  • 文章类型: Journal Article
    目的通过酶法制备具有钙结合能力的鲭鱼肽(MPs),并探讨其在体外提高钙生物利用度的潜在作用。钙结合能力,水解度(DH),分子量(MW),并测定了MPs的电荷分布随酶解时间的变化。使用光谱学和形态分析对鲭鱼肽-钙(MP-钙)复合物进行了结构表征。结果表明,当使用alcalase3h时,所得MPs的最大钙结合能力为120.95mg/g,DH为15.45%。此外,随着水解时间的增加,国会议员的MW减少了,负电荷增加。MPs的天冬氨酸(Asp)和谷氨酸(Glu)中的羧基和氨基可以充当钙结合位点,它们通过分子间相互作用与钙离子进一步组装成紧凑的纳米级球形复合物。此外,即使在草酸的影响下,MP-钙复合物保持一定的溶解度。本研究为开发新型钙补充剂和有效利用鲭鱼蛋白质资源提供了依据。
    The purpose of this study was to prepare mackerel peptides (MPs) with calcium-binding capacity through an enzyme method and to investigate the potential role they play in improving the bioavailability of calcium in vitro. The calcium-binding capacity, degree of hydrolysis (DH), molecular weight (MW), and charge distribution changes with the enzymolysis time of MPs were measured. The structural characterization of mackerel peptide-calcium (MP-calcium) complexes was performed using spectroscopy and morphology analysis. The results showed that the maximum calcium-binding capacity of the obtained MPs was 120.95 mg/g when alcalase was used for 3 h, with a DH of 15.45%. Moreover, with an increase in hydrolysis time, the MW of the MPs decreased, and the negative charge increased. The carboxyl and amino groups in aspartic (Asp) and glutamate (Glu) of the MPs may act as calcium-binding sites, which are further assembled into compact nanoscale spherical complexes with calcium ions through intermolecular interactions. Furthermore, even under the influence of oxalic acid, MP-calcium complexes maintained a certain solubility. This study provides a basis for developing new calcium supplements and efficiently utilizing the mackerel protein resource.
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