Stability analysis

稳定性分析
  • 文章类型: Journal Article
    目的:肿瘤微环境(TME)在肿瘤进展和治疗反应中起着至关重要的作用。Radiomics通过从医学图像中提取定量特征,提供了一种非侵入性的方法来研究TME。在这项研究中,我们提出了一种新的方法来评估前庭神经鞘瘤(VS)的TME中影像组学特征的稳定性和辨别能力。
    方法:分析242例VS患者的磁共振成像(MRI)数据,包括对比增强T1加权(ceT1)和高分辨率T2加权(hrT2)序列。从不同大小的同心肿瘤周围区域提取影像组学特征。利用组内相关系数(ICC)评估特征稳定性和判别能力,为ICCmin和ICCmax建立分位数阈值。
    结果:确定的ICCmin和ICCmax阈值分别为0.45和0.72。特征分为四类:稳定和判别(S-D),稳定和非判别(S-ND),不稳定和判别(US-D),以及不稳定和非判别性(US-ND)。在ceT1和hrT2序列中,不同的特征组表现出不同比例的S-D特征。使用Jaccard指数评估ceT1和hrT2序列之间的S-D特征的相似性,对于从0.68(强度特征)到1.00(相邻灰度色调差矩阵(NGTDM)特征)的所有特征组的值为0.78。
    结论:这项研究提供了一个框架,用于识别TME中稳定和有区别的放射组学特征,可以作为潜在的生物标志物或患者预后的预测因子,最终改善VS患者的管理。
    OBJECTIVE: The tumor microenvironment (TME) plays a crucial role in tumor progression and treatment response. Radiomics offers a non-invasive approach to studying the TME by extracting quantitative features from medical images. In this study, we present a novel approach to assess the stability and discriminative ability of radiomics features in the TME of vestibular schwannoma (VS).
    METHODS: Magnetic Resonance Imaging (MRI) data from 242 VS patients were analyzed, including contrast-enhanced T1-weighted (ceT1) and high-resolution T2-weighted (hrT2) sequences. Radiomics features were extracted from concentric peri-tumoral regions of varying sizes. The intraclass correlation coefficient (ICC) was used to assess feature stability and discriminative ability, establishing quantile thresholds for ICCmin and ICCmax.
    RESULTS: The identified thresholds for ICCmin and ICCmax were 0.45 and 0.72, respectively. Features were classified into four categories: stable and discriminative (S-D), stable and non-discriminative (S-ND), unstable and discriminative (US-D), and unstable and non-discriminative (US-ND). Different feature groups exhibited varying proportions of S-D features across ceT1 and hrT2 sequences. The similarity of S-D features between ceT1 and hrT2 sequences was evaluated using Jaccard\'s index, with a value of 0.78 for all feature groups which is ranging from 0.68 (intensity features) to 1.00 (Neighbouring Gray Tone Difference Matrix (NGTDM) features).
    CONCLUSIONS: This study provides a framework for identifying stable and discriminative radiomics features in the TME, which could serve as potential biomarkers or predictors of patient outcomes, ultimately improving the management of VS patients.
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  • 文章类型: Journal Article
    背景:PfK13蛋白突变与恶性疟原虫青蒿素抗性的出现有关。PfK13蛋白对于介导泛素化和控制PI3K/AKT途径至关重要。突变体PfK13变异会干扰底物结合,尤其是PfPI3K,这提高了PfPI3K水平。
    方法:DUET,DynaMut2,mCSM,iStable2.0,I-Mutant2.0和MuPro用于研究蛋白质稳定性,并使用HADDOCK2.4对接算法研究了野生型和突变型PfK13与PfPI3K的螺旋和催化结构域之间的蛋白质-底物结合。
    结果:i-Stable服务器分析预测,在与青蒿素抗性相关的9个突变中(F446I,Y493H,R539T,I543T,P553L,R561H,C580Y)降低了蛋白质的稳定性。催化结构域的HADDOCK评分强调了所报道的突变对PfK13蛋白的结合亲和力的显著影响。通过MM_GBSA技术进一步验证,野生型和突变型PfK13蛋白之间的结合自由能(ddG)分析揭示了由PfK13突变引起的相互作用的丧失。
    结论:研究发现表明,PfK13中的突变导致蛋白质结构不稳定,并影响PfPI3K的结合。尽管调查结果仍是初步的,需要进一步验证,考虑到PfK13和PfPI3K相互作用对克服青蒿素耐药性影响的重要性,为进一步研究提供了基础。
    BACKGROUND: PfK13 protein mutations are associated with the emergence of artemisinin resistance in Plasmodium falciparum. PfK13 protein is essential for mediating ubiquitination and controlling the PI3K/AKT pathway. Mutant PfK13 variations can interfere with substrate binding, especially with PfPI3K, which raises PfPI3K levels.
    METHODS: DUET, DynaMut2, mCSM, iStable 2.0, I-Mutant 2.0, and MuPro were utilized to study the protein stability and protein-substrate binding was studied using HADDOCK 2.4 docking algorithm between Wild-type and mutant PfK13 with the helical and catalytic domain of PfPI3K.
    RESULTS: i-Stable server analysis predicted that seven, out of the nine mutations associated with artemisinin resistance (F446I, Y493H, R539T, I543T, P553L, R561H, C580Y) reduced the protein stability. HADDOCK scores of the catalytic domain underscores the significant impact of the reported mutations on the binding affinity of the PfK13 protein. Further validation through the MM_GBSA technique, the binding free energy (DDG) between the wild-type and the mutant PfK13 protein analysis revealed a loss of interactions resulting from mutations in PfK13.
    CONCLUSIONS: The study finding suggest that mutations in the PfK13 cause destabilization in the protein structure and affects the binding of PfPI3K. Although the findings remain preliminary and require further validation, it provides the basis for further research considering the importance of the interaction of PfK13 and PfPI3K to overcome the impact of artemisinin resistance.
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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
    近年来,已经进行了许多尝试来开发用于从发酵液或复杂混合物中选择性地回收工业上重要的产物的低成本吸附剂。当前的研究是一种新颖的尝试,使用廉价的吸附剂如膨润土(BT)从哈茨木霉中选择性吸附酯酶,活性炭(AC),二氧化硅(SiO2),和二氧化钛(TiO2)。由于其594.45m3/g的较大表面积,AC具有最高的酯酶吸附率,为97.58%。发现SiO2比酯酶具有最高的选择性,估计纯化倍数为7.2。有趣的是,在BT提取的发酵液中发现5.5的纯化倍数。采用功能化(FT-IR)和形态分析(SEM-EDX)对酯酶的吸附进行表征。酯酶在AC上的吸附,SiO2和TiO2很好地拟合了Freundlich等温线,证明了酯酶的多层吸附。建立了各种吸附剂中酯酶吸附的伪二级动力学模型。热力学分析表明,吸附是一个吸热过程。AC具有最低的吉布斯自由能-10.96kJ/mol,这支持酯酶和蛋白质的自发最大吸附。在解吸研究中,使用氯化钠从TiO2中提取酯酶的最大回收率为41.34%。不像其他吸附剂,AC吸附酯酶保持了其催化活性和稳定性,暗示它可以用作商业应用的固定系统。根据动力学分析,反应的总速率由反应动力学而不是外部传质阻力控制,如Damkohler数字所示。
    In recent years, numerous attempts have been made to develop a low-cost adsorbent for selectively recovering industrially important products from fermentation broth or complex mixtures. The current study is a novel attempt to selectively adsorb esterase from Trichoderma harzianum using cheap adsorbents like bentonite (BT), activated charcoal (AC), silicon dioxide (SiO2), and titanium dioxide (TiO2). AC had the highest esterase adsorption of 97.58% due to its larger surface area of 594.45 m3/g. SiO2 was found to have the highest selectivity over esterase, with an estimated purification fold of 7.2. Interestingly, the purification fold of 5.5 was found in the BT-extracted fermentation broth. The functional (FT-IR) and morphological analysis (SEM-EDX) were used to characterize the adsorption of esterase. Esterase adsorption on AC, SiO2, and TiO2 was well fitted by Freundlich isotherm, demonstrating multilayer adsorption of esterase. A pseudo-second-order kinetic model was developed for esterase adsorption in various adsorbents. Thermodynamic analysis revealed that adsorption is an endothermic process. AC has the lowest Gibbs free energy of -10.96 kJ/mol, which supports the spontaneous maximum adsorption of both esterase and protein. In the desorption study, the maximum recovery of esterase from TiO2 using sodium chloride was 41.34 %. Unlike other adsorbents, the AC-adsorbed esterase maintained its catalytic activity and stability, implying that it could be used as an immobilization system for commercial applications. According to the kinetic analysis, the overall rate of the reaction was controlled by reaction kinetics rather than external mass transfer resistance, as indicated by the Damkohler number.
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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
    新冠肺炎强调了在对疾病动力学进行建模时考虑人类行为变化的重要性。这导致开发了各种结合人类行为的模型。我们的目标是有助于深入,这种模型的数学检验。这里,我们考虑了一个简单的确定性隔室模型,该模型具有人类行为的内生整合(即,行为反馈)通过经典的易感暴露感染恢复(SEIR)结构中的传播。尽管它简单,具有行为的SEIR结构(SEIRb)在预测中表现良好,尤其是与更复杂的模型相比。我们将此模型与SEIR模型进行了对比,该模型排除了行为的内生整合。这两个模型都假定对COVID-19具有永久免疫力,因此我们还考虑对这些模型进行修改,包括减弱免疫力(SEIRS和SEIRSb)。我们进行均衡,灵敏度,并对所有模型进行可识别性分析,并检查模型在美国各地复制COVID-19数据的保真度。行为的内生整合显著提高了模型产生现实爆发的能力。虽然这两个内生模型在可识别性和敏感性方面相似,SEIRSb模型,随着免疫力下降的更准确的假设,通过允许存在地方性均衡来加强初始SEIRb模型,COVID-19动力学的一个现实特征。将模型拟合到数据时,我们进一步考虑增加影响疾病传播的简单季节性,以突出模型的解释力。
    COVID-19 highlighted the importance of considering human behavior change when modeling disease dynamics. This led to developing various models that incorporate human behavior. Our objective is to contribute to an in-depth, mathematical examination of such models. Here, we consider a simple deterministic compartmental model with endogenous incorporation of human behavior (i.e., behavioral feedback) through transmission in a classic Susceptible-Exposed-Infectious-Recovered (SEIR) structure. Despite its simplicity, the SEIR structure with behavior (SEIRb) was shown to perform well in forecasting, especially compared to more complicated models. We contrast this model with an SEIR model that excludes endogenous incorporation of behavior. Both models assume permanent immunity to COVID-19, so we also consider a modification of the models which include waning immunity (SEIRS and SEIRSb). We perform equilibria, sensitivity, and identifiability analyses on all models and examine the fidelity of the models to replicate COVID-19 data across the United States. Endogenous incorporation of behavior significantly improves a model\'s ability to produce realistic outbreaks. While the two endogenous models are similar with respect to identifiability and sensitivity, the SEIRSb model, with the more accurate assumption of the waning immunity, strengthens the initial SEIRb model by allowing for the existence of an endemic equilibrium, a realistic feature of COVID-19 dynamics. When fitting the model to data, we further consider the addition of simple seasonality affecting disease transmission to highlight the explanatory power of the models.
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