computational modelling

计算建模
  • 文章类型: Journal Article
    光动力疗法(PDT)是一种使用光,光敏剂,和氧气产生细胞毒性化合物,消除恶性细胞。最近,微流体系统已用于分析光敏剂(PS),因为它们具有在体内环境中复制的潜力。虽然先前的研究已经建立了反应的单线态氧浓度和PDT诱导的细胞死亡之间的强相关性,环境流体流动可能对氧气和PS浓度的影响在许多情况下都被忽视了,这限制了结果的可靠性。在这里,我们将氧气和PS在整个环境介质中以及球形多细胞聚集体内的运输相结合,以初步研究辐射前后整个球体中氧气和PS浓度以及PDT诱导的细胞死亡的分布。获得的结果表明,PDT诱导的细胞死亡始于球状体的表面,随后扩散到相邻区域,这与实验结果非常吻合。之后,药光间隔(DLI)的影响,通量率,PS组成,微通道高度,和入口流速对治疗结果的影响进行了研究。研究结果表明,充分的DLI对于确保PS在整个培养基中的均匀分布至关重要,发现5小时的值就足够了。PS的组成至关重要,ALA-PpIX诱导早期细胞死亡,但加速氧消耗,尤其是在外层,剥夺PDT所需的内层氧气,与mTHPC和Photofrin相比,这反过来又破坏并延长了曝光时间。尽管注量率直接影响单线态氧生成率,将注量率增加189mW/cm2不会显着受益。微孔高度和入口流量涉及竞争现象-增加高度或减少流量会减少氧气供应并增加PS“冲刷”及其浓度。
    Photodynamic therapy (PDT) is a medical radio chemotherapeutic method that uses light, photosensitizing agents, and oxygen to produce cytotoxic compounds, which eliminate malignant cells. Recently, Microfluidic systems have been used to analyse photosensitizers (PSs) due to their potential to replicate in vivo environments. While prior studies have established a strong correlation between reacted singlet oxygen concentration and PDT-induced cellular death, the effects that the ambient fluid flow might have on the concentration of oxygen and PS have been disregarded in many, which limits the reliability of the results. Herein, we coupled the transport of oxygen and PS throughout the ambient medium and within the spheroidal multicellular aggregate to initially study the profiles of oxygen and PS concentration alongside PDT-induced cellular death throughout the spheroid before and after radiation. The attained results indicate that the PDT-induced cellular death initiates on the surface of the spheroids and subsequently spreads to the neighbouring regions, which is in great accordance with experimental results. Afterward, the effects that drug-light interval (DLI), fluence rate, PS composition, microchannel height, and inlet flow rate have on the therapeutic outcomes are studied. The findings show that adequate DLI is critical to ensure uniform distribution of PS throughout the medium, and a value of 5 h was found to be sufficient. The composition of PS is critical, as ALA-PpIX induces earlier cell death but accelerates oxygen consumption, especially in the outer layers, depriving the inner layers of oxygen necessary for PDT, which in turn disrupts and prolongs the exposure time compared to mTHPC and Photofrin. Despite the fluence rate directly influencing the singlet oxygen generation rate, increasing the fluence rate by 189 mW/cm2 would not significantly benefit us. Microwell height and inlet flow rate involve competing phenomena-increasing height or decreasing flow reduces oxygen supply and increases PS \"washout\" and its concentration.
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  • 文章类型: Journal Article
    由于长期住院而获得的感染,并且在患者进入医疗机构2天后出现感染,可以归类为医院获得性感染。肺炎克雷伯菌(K.肺炎)已成为一种关键病原体,由于高毒力和耐碳青霉烯类菌株的发病率上升,在全球引起严重关注。谷氧还蛋白是一种氧化还原蛋白,可与谷胱甘肽结合以减少混合的二硫化物,从而保护细胞免受氧化应激。蛋白腺苷酰转移酶(PrAT)是一种假激酶,具有将AMP基团从ATP转移到谷氧还蛋白的机制。通过抑制PrAT的活性来诱导细菌的氧化应激是对抗其对医院获得性感染的贡献的有希望的方法。因此,这项研究旨在过度表达,净化,分析ATP和Mg2+与肺炎克雷伯菌PrAT(KpPrAT)的结合作用。pET表达系统和镍亲和层析可有效表达和纯化KpPrAT。远紫外CD光谱表明该蛋白质主要是α-螺旋,即使在Mg2+的存在下。用ANS的外在荧光光谱表明在ATP和Mg2+的存在下存在疏水口袋,而Mant-ATP研究暗示了KpPrAT的潜在核苷酸结合能力。Mg2+的存在增加了蛋白质的热稳定性。等温滴定量热法可深入了解与ATP与KpPrAT结合相关的结合亲和力和热力学参数,有或没有Mg2+。最后,Mg2+的存在诱导KpPrAT中有利于核苷酸结合的构象。
    Infections that are acquired due to a prolonged hospital stay and manifest 2 days following the admission of a patient to a health-care institution can be classified as hospital-acquired infections. Klebsiella pneumoniae (K. pneumoniae) has become a critical pathogen, posing serious concern globally due to the rising incidences of hypervirulent and carbapenem-resistant strains. Glutaredoxin is a redox protein that protects cells from oxidative stress as it associates with glutathione to reduce mixed disulfides. Protein adenylyltransferase (PrAT) is a pseudokinase with a proposed mechanism of transferring an AMP group from ATP to glutaredoxin. Inducing oxidative stress to the bacterium by inhibiting the activity of PrAT is a promising approach to combating its contribution to hospital-acquired infections. Thus, this study aims to overexpress, purify, and analyse the effects of ATP and Mg2+ binding to Klebsiella pneumoniae PrAT (KpPrAT). The pET expression system and nickel affinity chromatography were effective in expressing and purifying KpPrAT. Far-UV CD spectroscopy demonstrates that the protein is predominantly α-helical, even in the presence of Mg2+. Extrinsic fluorescence spectroscopy with ANS indicates the presence of a hydrophobic pocket in the presence of ATP and Mg2+, while mant-ATP studies allude to the potential nucleotide binding ability of KpPrAT. The presence of Mg2+ increases the thermostability of the protein. Isothermal titration calorimetry provides insight into the binding affinity and thermodynamic parameters associated with the binding of ATP to KpPrAT, with or without Mg2+. Conclusively, the presence of Mg2+ induces a conformation in KpPrAT that favours nucleotide binding.
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  • 文章类型: Journal Article
    阅读对于获取知识至关重要,研究表明,在阅读障碍儿童中,以语音为重点的干预措施通常比以英语为重点的干预措施产生更大的改善。然而,阅读教学的有效性因人而异。在影响阅读技能的各种因素中,如阅读接触和口语技能,阅读教学对于促进儿童发展成为熟练读者至关重要;它可以显著影响阅读策略,并有助于阅读的个体差异。为了调查这个假设,我们使用优化的MikeNet模拟器开发了阅读的计算模型。根据教育实践,该模型接受了三种不同教学方法的训练:以语音为重点的训练,以意义为中心的培训,和语音意义上的平衡训练。我们使用了语义依赖(SR),在模型中不同训练条件下,对打印到声音和打印到含义映射的相对依赖性的度量,作为阅读中个体差异的指标。仿真结果表明,SR级别与阅读指令类型之间存在直接联系。此外,SR分数能够预测朗读任务中的模型表现:较高的SR分数与语音错误增加和语音激活减少相关。这些发现与行为和神经影像学研究的数据一致,并提供了有关教学方法对阅读行为影响的见解。同时揭示了阅读中的个体差异以及为初学者整合OP和OS教学方法的重要性。
    Reading is vital for acquiring knowledge and studies have demonstrated that phonology-focused interventions generally yield greater improvements than meaning-focused interventions in English among children with reading disabilities. However, the effectiveness of reading instruction can vary among individuals. Among the various factors that impact reading skills like reading exposure and oral language skills, reading instruction is critical in facilitating children\'s development into skilled readers; it can significantly influence reading strategies, and contribute to individual differences in reading. To investigate this assumption, we developed a computational model of reading with an optimised MikeNet simulator. In keeping with educational practices, the model underwent training with three different instructional methods: phonology-focused training, meaning-focused training, and phonology-meaning balanced training. We used semantic reliance (SR), a measure of the relative reliance on print-to-sound and print-to-meaning mappings under the different training conditions in the model, as an indicator of individual differences in reading. The simulation results demonstrated a direct link between SR levels and the type of reading instruction. Additionally, the SR scores were able to predict model performance in reading-aloud tasks: higher SR scores were correlated with increased phonological errors and reduced phonological activation. These findings are consistent with data from both behavioral and neuroimaging studies and offer insights into the impact of instructional methods on reading behaviors, while revealing individual differences in reading and the importance of integrating OP and OS instruction approaches for beginning readers.
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  • 文章类型: Editorial
    暂无摘要。
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  • 文章类型: Journal Article
    从单波长异常衍射X射线数据求解蛋白质的结构时,通过从异常散射子结构定相获得的初始相通常需要通过迭代电子密度修改来改善。在这份手稿中,提出了使用卷积神经网络(CNN)分割初始实验定相电子密度图。报告的结果表明,具有U网架构的CNN,在监督学习中,主要使用蛋白质数据库中的X射线数据生成的数千个电子密度图进行训练,可以提高电流密度的改性方法。
    When solving a structure of a protein from single-wavelength anomalous diffraction X-ray data, the initial phases obtained by phasing from an anomalously scattering substructure usually need to be improved by an iterated electron-density modification. In this manuscript, the use of convolutional neural networks (CNNs) for segmentation of the initial experimental phasing electron-density maps is proposed. The results reported demonstrate that a CNN with U-net architecture, trained on several thousands of electron-density maps generated mainly using X-ray data from the Protein Data Bank in a supervised learning, can improve current density-modification methods.
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  • 文章类型: Editorial
    现有的创伤后应激障碍(PTSD)理论激发了大量的研究,并为我们当前的知识库做出了重大贡献。然而,大多数理论都是定性和口头的,并且可能难以相互评估和比较。在本文中,我们提出一种前进的方法是使用计算模型来制定更精确的PTSD理论,可以通过(1)评估模型是否可以解释与PTSD相关的基本现象,(2)将模拟结果与真实数据进行比较。计算建模可以迫使我们更精确地描述过程,并获得更强大的理论,这些理论可以用于测试。在进行实证研究之前,建立理论基础可以帮助我们避免以有效结果的低概率进行研究,并抵消心理学中的可复制性危机。总之,计算建模是促进对PTSD的理解和治疗的有希望的途径。
    计算模型可以帮助我们指定参与PTSD的心理过程,这可能会增加我们对如何最好地帮助人们在创伤事件后恢复的理解。有了创伤后应激障碍的计算模型,我们可以模拟理论原理的后果,并确保设计理论基础良好的研究。要验证计算模型,仍需要高质量的经验数据。
    The existing theories of post-traumatic stress disorder (PTSD) have inspired large volumes of research and have contributed substantially to our current knowledge base. However, most of the theories are of a qualitative and verbal nature, and may be difficult to evaluate and compare with each other. In this paper, we propose that one way forward is to use computational modelling to formulate more precise theories of PTSD that can be evaluated by (1) assessing whether the model can explain fundamental phenomena related to PTSD, and (2) comparing simulated outcomes with real data. Computational modelling can force us to describe processes more precisely and achieve stronger theories that are viable for testing. Establishing the theoretical groundwork before undertaking empirical studies can help us to avoid doing research with low probability of valid results, and counteract the replicability crisis in psychology. In conclusion, computational modelling is a promising avenue for advancing the understanding and treatment of PTSD.
    Computational modelling can help us to specify the psychological processes involved in PTSD, which may increase our understanding of how best to help people to recover after traumatic events.With computational models of PTSD, we can simulate the consequences of the theoretical principles and make sure to design research studies that are theoretically well grounded.To validate the computational models, high-quality empirical data are still needed.
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  • 文章类型: Journal Article
    氧化还原翻译后修饰(氧化还原-PTM)是蛋白质氨基酸的化学变化。氧化还原-PTM参与蛋白质构象的调节,本地化和功能,充当影响细胞中许多基本生化过程的信号效应物。至关重要的是,蛋白质的氧化还原-PTM的失调与许多人类疾病的病理生理学有关,包括神经退行性疾病,如阿尔茨海默病和帕金森病。这篇综述旨在强调氧化还原-PTMs生物学领域目前的知识空白,并探索蛋白质组学和计算模型的新方法进展,这将为更好地理解蛋白质的氧化还原-PTMs在神经退行性疾病中的作用和治疗潜力铺平道路。这里,我们总结了蛋白质的氧化还原-PTM的主要类型,同时提供了它们在神经退行性疾病中发生的例子,并概述了用于检测它们的最新方法。我们探索了新型计算建模方法作为必要工具的潜力,以了解氧化还原-PTM在调节蛋白质结构和功能中的精确作用。我们还讨论了在活细胞中发生的各种PTM之间的复杂串扰。最后,我们认为,蛋白质的氧化还原-PTMs将来可用作神经退行性疾病的诊断和预后生物标志物.
    Oxidation-reduction post-translational modifications (redox-PTMs) are chemical alterations to amino acids of proteins. Redox-PTMs participate in the regulation of protein conformation, localization and function, acting as signalling effectors that impact many essential biochemical processes in the cells. Crucially, the dysregulation of redox-PTMs of proteins has been implicated in the pathophysiology of numerous human diseases, including neurodegenerative diseases such as Alzheimer\'s disease and Parkinson\'s disease. This review aims to highlight the current gaps in knowledge in the field of redox-PTMs biology and to explore new methodological advances in proteomics and computational modelling that will pave the way for a better understanding of the role and therapeutic potential of redox-PTMs of proteins in neurodegenerative diseases. Here, we summarize the main types of redox-PTMs of proteins while providing examples of their occurrence in neurodegenerative diseases and an overview of the state-of-the-art methods used for their detection. We explore the potential of novel computational modelling approaches as essential tools to obtain insights into the precise role of redox-PTMs in regulating protein structure and function. We also discuss the complex crosstalk between various PTMs that occur in living cells. Finally, we argue that redox-PTMs of proteins could be used in the future as diagnosis and prognosis biomarkers for neurodegenerative diseases.
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  • 文章类型: Journal Article
    这里,扩展范围高能量分辨率荧光检测(XR-HERFD)的新技术已成功地高精度观察了锰中n=2的卫星。所提出的卫星签名的重要性是数百个标准误差,并且远远超出了三到六个标准误差的典型发现水平。该卫星是凝聚态中所有含锰材料的敏感指标。测量的不确定度已经定义,它清楚地观察到多个峰和结构,表明复杂的物理量子力学过程。能量特征值的理论计算,还给出了抖落概率和螺旋率,这解释了卫星的起源来自物理n=2个抖动过程。相对于锰的完整Kα光谱测量该卫星的强度演变,以研究卫星结构,因此,多体过程,作为入射能量的函数。结果表明,多体还原因子S02不应像目前所做的那样用恒定值建模。这项工作对理解多体过程和以定量方式解释HERFD或共振非弹性X射线散射光谱的挑战做出了重大贡献。
    Here, the novel technique of extended-range high-energy-resolution fluorescence detection (XR-HERFD) has successfully observed the n = 2 satellite in manganese to a high accuracy. The significance of the satellite signature presented is many hundreds of standard errors and well beyond typical discovery levels of three to six standard errors. This satellite is a sensitive indicator for all manganese-containing materials in condensed matter. The uncertainty in the measurements has been defined, which clearly observes multiple peaks and structure indicative of complex physical quantum-mechanical processes. Theoretical calculations of energy eigenvalues, shake-off probability and Auger rates are also presented, which explain the origin of the satellite from physical n = 2 shake-off processes. The evolution in the intensity of this satellite is measured relative to the full Kα spectrum of manganese to investigate satellite structure, and therefore many-body processes, as a function of incident energy. Results demonstrate that the many-body reduction factor S02 should not be modelled with a constant value as is currently done. This work makes a significant contribution to the challenge of understanding many-body processes and interpreting HERFD or resonant inelastic X-ray scattering spectra in a quantitative manner.
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  • 文章类型: Journal Article
    通过不同运输路线的细胞内货物递送依赖于囊泡载体。关键的贩运途径通过早期内体分配由网格蛋白介导的内吞作用(CME)吸收的货物。内体网络的高度动态性对其定量分析提出了挑战,和理论建模方法可以帮助阐明内体贩运系统的组织。这里,我们引入了一种新的计算建模方法来评估内体分布。我们采用了诱导多能干细胞衍生的心肌细胞(iPSC-CM)模型,其遗传突变导致扩张型心肌病(DCM)。在这个模型中,由于CME依赖性信号传导受损,囊泡分布有缺陷,导致质膜定位的早期内体。我们在携带两种不同突变的iPSC-CM中概述了这一点,TPM1-L185F和TnT-R141W(MUT),使用3D共聚焦成像以及超分辨率STED显微镜。我们根据细胞的球形近似计算了EEA1阳性囊泡的缩放距离分布。采用这种方法,3D球形建模确定了MUTiPSC-CM中早期内体种群的双峰分离,与WT对照相比。此外,球形建模证实了RhoAII处理的MUTiPSC-CM中双峰囊泡定位的回归。这反映了恢复,在通过RhoAII依赖性RhoA激活挽救CME依赖性信号后,MUTiPSC-CM内早期内体的均匀分布。总的来说,我们的方法能够评估基于细胞的疾病模型中的早期内体分布.这种新方法可以进一步深入了解不同生理场景中的内体网络的动力学。
    Intracellular cargo delivery via distinct transport routes relies on vesicle carriers. A key trafficking route distributes cargo taken up by clathrin-mediated endocytosis (CME) via early endosomes. The highly dynamic nature of the endosome network presents a challenge for its quantitative analysis, and theoretical modelling approaches can assist in elucidating the organization of the endosome trafficking system. Here, we introduce a new computational modelling approach for assessment of endosome distributions. We employed a model of induced pluripotent stem cell-derived cardiomyocytes (iPSC-CMs) with inherited mutations causing dilated cardiomyopathy (DCM). In this model, vesicle distribution is defective due to impaired CME-dependent signaling, resulting in plasma membrane-localized early endosomes. We recapitulated this in iPSC-CMs carrying two different mutations, TPM1-L185F and TnT-R141W (MUT), using 3D confocal imaging as well as super-resolution STED microscopy. We computed scaled distance distributions of EEA1-positive vesicles based on a spherical approximation of the cell. Employing this approach, 3D spherical modelling identified a bi-modal segregation of early endosome populations in MUT iPSC-CMs, compared to WT controls. Moreover, spherical modelling confirmed reversion of the bi-modal vesicle localization in RhoA II-treated MUT iPSC-CMs. This reflects restored, homogeneous distribution of early endosomes within MUT iPSC-CMs following rescue of CME-dependent signaling via RhoA II-dependent RhoA activation. Overall, our approach enables assessment of early endosome distribution in cell-based disease models. This new method may provide further insight into the dynamics of endosome networks in different physiological scenarios.
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  • 文章类型: Journal Article
    由面部外观形成的第一印象预测重要的社会结果。这些印象的现有模型表明,它们是由效价和优势的维度支撑的,通常是通过将数据缩减方法应用于一系列特征的面部明确评级而得出的。然而,这种方法存在潜在的问题,因为特质评级可能无法完全捕获人们自发评估面孔的维度.这里,我们使用自然语言处理直接从参与者的自由文本描述中提取“主题”(即,他们的第一印象)2222张人脸图像。出现了两个话题,反映与积极情绪效价和温暖(主题1)以及消极情绪效价和潜在威胁(主题2)相关的第一印象。接下来,我们调查了这些主题如何与来自显性性状评级的效价和优势成分相关.总的来说,这些成分仅解释了从自由文本描述中提取的主题差异的约44%,并建议第一印象由包含现有基于特质评级的模型的内容的相关效价维度支撑。自然语言为理解社会认知提供了一个有希望的新途径,未来的工作可以检查自然语言和传统数据驱动模型在不同社会背景下的印象的预测效用。
    First impressions formed from facial appearance predict important social outcomes. Existing models of these impressions indicate they are underpinned by dimensions of Valence and Dominance, and are typically derived by applying data reduction methods to explicit ratings of faces for a range of traits. However, this approach is potentially problematic because the trait ratings may not fully capture the dimensions on which people spontaneously assess faces. Here, we used natural language processing to extract \'topics\' directly from participants\' free-text descriptions (i.e., their first impressions) of 2222 face images. Two topics emerged, reflecting first impressions related to positive emotional valence and warmth (Topic 1) and negative emotional valence and potential threat (Topic 2). Next, we investigated how these topics were related to Valence and Dominance components derived from explicit trait ratings. Collectively, these components explained only ~44% of the variance in the topics extracted from free-text descriptions and suggested that first impressions are underpinned by correlated valence dimensions that subsume the content of existing trait-rating-based models. Natural language offers a promising new avenue for understanding social cognition, and future work can examine the predictive utility of natural language and traditional data-driven models for impressions in varying social contexts.
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