Stacking

堆叠
  • 文章类型: Journal Article
    长时间的伤口引流(PWD)是增加关节成形术后早期假体周围感染风险的最重要原因之一。在关节置换术后手术领域评估PWD的危险因素非常重要。这可以使用机器学习或人工智能方法来实现。我们在这项研究中的目的是比较机器学习方法在预测可能的PWD。
    这项研究是在临床上进行的,实验室,313例股骨近端骨折患者的影像学资料。我们对数据集进行了预处理,并使用交叉验证对机器学习方法进行了训练和测试。我们比较了各种机器学习算法(线性判别分析,决策树,k-最近的邻居,梯度增压机,和逻辑回归[LR])基于绩效指标。我们还将最成功的算法与元分类器结合在一起。为了帮助理解风险因素之间的关系,我们提供了风险因素严重程度排序.
    为了估计PWD的风险,使用一级分类器进行分类,然后整合为基于LR的元学习器堆叠方法.使用堆叠方法实现了更多的性能改进。
    我们发现堆叠方法在PWD分类中优于其他方法。我们确定从排水管收集的液体量,病态肥胖类,输血,和体重指数评分是四个最重要的危险因素。
    UNASSIGNED: Prolonged wound drainage (PWD) is one of the most important reasons that increase the risk of early periprosthetic joint infection after arthroplasty. It is very important to evaluate the risk factors for PWD in the surgical field after arthroplasty surgery. This can be accomplished using machine learning or artificial intelligence methods. Our aim in this study was to compare machine learning methods in predicting possible PWD.
    UNASSIGNED: The study was carried out on clinical, laboratory, and radiological data of 313 patients who underwent hemiarthroplasty (HA) for proximal femur fractures. We preprocessed the dataset and trained and tested machine learning methods using cross validation. We compared various machine learning algorithms (linear discriminant analysis, decision tree, k-nearest neighbors, gradient boosting machine, and logistic regression [LR]) based on performance measures. We also combined the most successful algorithms with a metaclassifier. To help understand the relationship between risk factors, we provided a risk factor severity ranking.
    UNASSIGNED: To estimate the risk of PWD, classification was performed with first-level classifiers and then integrated as a LR-based meta-learner stacking method. More performance improvements were achieved with the stacking method.
    UNASSIGNED: We found that the stacking method was superior to other methods in PWD classification. We determined that the volume of fluid collected from the drain, morbid obesity class, blood transfusion, and body mass index score were the four most important risk factors according to stacking.
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  • 文章类型: Journal Article
    糖尿病(DM)期间的长期高血糖与可能影响前眼和后眼节的严重并发症有关。导致视力受损或失明。角膜是眼睛的重要部分,其具有作为保护性透明屏障和作为主要屈光结构的双重作用,并且同样受到DM中的高血糖的负面影响。了解与DM相关的表型变化的细胞和分子机制对于开发靶向治疗以促进组织完整性至关重要。在这个概念验证研究中,我们应用基于细胞片的方法,使用从尸体对照(健康)分离的原代人角膜成纤维细胞产生生理角膜厚度的堆叠构建体,1型DM和2型DM角膜组织。培养2周后生成自组装角膜基质片,孤立的,随后组装以创建堆叠结构,使用透射电子显微镜进行评估。基因表达模式分析显示纤维化标志物显著下调,α-平滑肌肌动蛋白,和3型胶原蛋白,与对照相比,在2型DM构建体中堆叠。与对照相比,IGF1表达在2型DM构建体中显著上调,通过堆叠诱导显著降低。这项研究描述了一种较厚的发展,自组装角膜基质构建体作为评估与DM衍生角膜成纤维细胞相关的表型差异的平台,并能够开发靶向治疗以促进角膜完整性。
    Prolonged hyperglycemia during diabetes mellitus (DM) is associated with severe complications that may affect both the anterior and posterior ocular segments, leading to impaired vision or blindness. The cornea is a vital part of the eye that has a dual role as a protective transparent barrier and as a major refractive structure and is likewise negatively affected by hyperglycemia in DM. Understanding the cellular and molecular mechanisms underlying the phenotypic changes associated with DM is critical to developing targeted therapies to promote tissue integrity. In this proof-of-concept study, we applied a cell sheet-based approach to generate stacked constructs of physiological corneal thickness using primary human corneal fibroblasts isolated from cadaveric control (healthy), Type 1 DM and Type 2 DM corneal tissues. Self-assembled corneal stromal sheets were generated after 2 weeks in culture, isolated, and subsequently assembled to create stacked constructs, which were evaluated using transmission electron microscopy. Analysis of gene expression patterns revealed significant downregulation of fibrotic markers, α-smooth muscle actin, and collagen type 3, with stacking in Type 2 DM constructs when compared to controls. IGF1 expression was significantly upregulated in Type 2 DM constructs compared to controls with a significant reduction induced by stacking. This study describes the development of a thicker, self-assembled corneal stromal construct as a platform to evaluate phenotypic differences associated with DM-derived corneal fibroblasts and enable the development of targeted therapeutics to promote corneal integrity.
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  • 文章类型: Journal Article
    高血压是一个主要的公共卫生问题,及其导致的其他心血管疾病是全球死亡的主要原因。在这项研究中,我们构建了一个方便、高效的高血压风险预测模型来辅助临床诊断和探索其他重要影响因素。
    我们包括来自NHANES的8073人(2017年至2020年3月),使用它们的120个特征来形成原始数据集。数据预处理后,我们通过LASSO回归和相关分析去除了几个冗余特征.13种常用的机器学习方法被用来构建预测模型,然后,性能较好的方法与递归特征消除相结合,以确定最佳特征子集。通过SMOTE实现数据平衡后,我们整合了这些表现较好的学习者,构建了一个基于堆叠策略预测高血压风险的融合模型.此外,探讨血清铁蛋白与高血压发病风险的关系,我们进行了单变量分析,并按四分位数将其分为四个水平组(Q1至Q4),以最低级别组(Q1)为参考,进行多元logistic回归分析和趋势分析。
    最佳特征子集为:年龄,BMI,腰部,SBP,DBP,Cre,UACR,血清铁蛋白,HbA1C,医生建议减少盐的摄入量。与其他机器学习模型相比,所构建的融合模型显示出更好的预测性能和精度,准确度,召回,F1值和AUC分别为0.871、0.873、0.871、0.869和0.966。为分析血清铁蛋白与高血压的关系,在控制所有协变量后,与第一季度相比,第二季度至第四季度的OR和95%CI为1.396(1.176-1.658),1.499(1.254-1.791),和1.645(1.360-1.989),分别,P<0.01,趋势P<0.001。
    本研究开发的高血压风险预测模型仅具有10种低成本且易于获取的特征,就可以有效预测高血压,这在辅助临床诊断方面具有成本效益。我们还发现血清铁蛋白水平与高血压风险之间存在趋势相关性。
    UNASSIGNED: Hypertension is a major public health problem, and its resulting other cardiovascular diseases are the leading cause of death worldwide. In this study, we constructed a convenient and high-performance hypertension risk prediction model to assist in clinical diagnosis and explore other important influencing factors.
    UNASSIGNED: We included 8,073 people from NHANES (2017-March 2020), using their 120 features to form the original dataset. After data pre-processing, we removed several redundant features through LASSO regression and correlation analysis. Thirteen commonly used machine learning methods were used to construct prediction models, and then, the methods with better performance were coupled with recursive feature elimination to determine the optimal feature subset. After data balancing through SMOTE, we integrated these better-performing learners to construct a fusion model based for predicting hypertension risk on stacking strategy. In addition, to explore the relationship between serum ferritin and the risk of hypertension, we performed a univariate analysis and divided it into four level groups (Q1 to Q4) by quartiles, with the lowest level group (Q1) as the reference, and performed multiple logistic regression analysis and trend analysis.
    UNASSIGNED: The optimal feature subsets were: age, BMI, waist, SBP, DBP, Cre, UACR, serum ferritin, HbA1C, and doctors recommend reducing salt intake. Compared to other machine learning models, the constructed fusion model showed better predictive performance with precision, accuracy, recall, F1 value and AUC of 0.871, 0.873, 0.871, 0.869 and 0.966, respectively. For the analysis of the relationship between serum ferritin and hypertension, after controlling for all co-variates, OR and 95% CI from Q2 to Q4, compared to Q1, were 1.396 (1.176-1.658), 1.499 (1.254-1.791), and 1.645 (1.360-1.989), respectively, with P < 0.01 and P for trend <0.001.
    UNASSIGNED: The hypertension risk prediction model developed in this study is efficient in predicting hypertension with only 10 low-cost and easily accessible features, which is cost-effective in assisting clinical diagnosis. We also found a trend correlation between serum ferritin levels and the risk of hypertension.
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  • 文章类型: Journal Article
    我们试图建立一个预测脓毒症患者住院期间死亡风险的模型。
    从临床记录挖掘数据库收集脓毒症患者的数据,2013年1月至2022年8月在温州医科大学附属东阳医院住院。将这些纳入的患者分为建模组和验证组。在建模组中,使用单变量和多变量回归分析确定住院期间死亡的独立危险因素.经过逐步回归分析(两个方向),画了一个列线图。用受试者工作特征(ROC)曲线的曲线下面积(AUC)评价模型的辨别能力,和GiViTI校准图表评估模型校准。进行下降曲线分析(DCA)以评估预测模型的临床有效性。在验证组中,将逻辑回归模型与SOFA评分系统建立的模型进行比较,随机森林方法,和堆叠方法。
    本研究共纳入1740名受试者,1218在建模群体中,522在验证群体中。结果表明,血清胆碱酯酶,总胆红素,呼吸衰竭,乳酸,肌酐,脑钠肽前体是死亡的独立危险因素。模型组和验证组的AUC值分别为0.847和0.826。两组人群中校准图的P值分别为0.838和0.771。DCA曲线高于两个极端曲线。此外,SOFA评分系统建立的模型的AUC值,随机森林方法,验证组中的堆叠法和堆叠法分别为0.777、0.827和0.832。
    结合多个危险因素建立的列线图模型可以有效预测脓毒症患者住院期间的死亡风险。
    UNASSIGNED: We attempted to establish a model for predicting the mortality risk of sepsis patients during hospitalization.
    UNASSIGNED: Data on patients with sepsis were collected from a clinical record mining database, who were hospitalized at the Affiliated Dongyang Hospital of Wenzhou Medical University between January 2013 and August 2022. These included patients were divided into modeling and validation groups. In the modeling group, the independent risk factors of death during hospitalization were determined using univariate and multi-variate regression analyses. After stepwise regression analysis (both directions), a nomogram was drawn. The discrimination ability of the model was evaluated using the area under the curve (AUC) of the receiver operating characteristic (ROC) curve, and the GiViTI calibration chart assessed the model calibration. The Decline Curve Analysis (DCA) was performed to evaluate the clinical effectiveness of the prediction model. Among the validation group, the logistic regression model was compared to the models established by the SOFA scoring system, random forest method, and stacking method.
    UNASSIGNED: A total of 1740 subjects were included in this study, 1218 in the modeling population and 522 in the validation population. The results revealed that serum cholinesterase, total bilirubin, respiratory failure, lactic acid, creatinine, and pro-brain natriuretic peptide were the independent risk factors of death. The AUC values in the modeling group and validation group were 0.847 and 0.826. The P values of calibration charts in the two population sets were 0.838 and 0.771. The DCA curves were above the two extreme curves. Moreover, the AUC values of the models established by the SOFA scoring system, random forest method, and stacking method in the validation group were 0.777, 0.827, and 0.832, respectively.
    UNASSIGNED: The nomogram model established by combining multiple risk factors could effectively predict the mortality risk of sepsis patients during hospitalization.
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  • 文章类型: Journal Article
    Tetrathiafulvalene (TTF) and its derivatives are very well known as electron donors with widespread use in the field of organic conductors and superconductors. Stacking interactions between two neutral TTF fragments were studied by analysing data from Cambridge Structural Database crystal structures and by quantum chemical calculations. Analysis of the contacts found in crystal structures shows high occurrence of parallel displaced orientations of TTF molecules. In the majority of the contacts, two TTF molecules are displaced along their longer C2 axis. The most frequent geometry has the strongest TTF-TTF stacking interaction, with CCSD(T)/CBS energy of -9.96 kcal mol-1. All the other frequent geometries in crystal structures are similar to geometries of the minima on the calculated potential energy surface.
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  • 文章类型: Journal Article
    细胞外斑块,阿尔茨海默病大脑的标志,由淀粉样β肽聚集产生的不溶性淀粉样原纤维组成。目前采用的少数治疗选择都没有,解决疾病的原因。相反,它们减少了疾病的症状。因此,抑制聚集体的聚集或不稳定,作为一种优选的治疗方法出现。设计抑制剂或去稳定剂需要对β淀粉样蛋白残基的全面了解,这些残基负责聚集体的显着结构稳定性。出于目的,我们通过分子动力学模拟比较了淀粉样蛋白β原原纤维的β-链-转角-β-链基序的13个芯片突变(单和双)与野生型对应物对结构不稳定的影响.除了已知的K28和D23之间的盐桥相互作用之外,我们的分析揭示了K28作为附近存在的唯一正电荷的更重要的作用。在两个连续的芳香残基中,F19参与堆叠相互作用;尽管F20突变的影响更明显。A21和V36的面对面布置充当支柱,维持连续链之间的必要最佳距离以促进稳定相互作用。除了为第一β链提供稳定性外,大尺寸的带负电荷的E22通过确保D23和K28的固定相对位置来促进盐桥形成。同样,疏水残基I32和L34包装原纤核,再次促进盐桥互动。Prospective,这些发现可用于有效鉴定或设计导致原原纤维不稳定的支架。由RamaswamyH.Sarma沟通。
    Extracellular plaques, the hallmark of Alzheimer\'s disease brains, consist of insoluble amyloid fibrils that result from the aggregation of amyloid beta peptides. None of the few therapeutic options currently adopted, address the cause of the disease. Instead, they reduce symptom of the disease. Inhibition of aggregation or destabilization of aggregates therefore, emerges as a preferable therapeutic approach. Designing inhibitors or destabilizers demands comprehensive knowledge of the residues of amyloid beta responsible for the phenomenal structural stability of the aggregate. For the purpose, we have compared the effect on structural destabilization of 13 in silico mutations (single and double) with the wild type counterpart of beta-strand-turn-beta-strand motif of the amyloid beta protofibrils by molecular dynamics simulation. Besides the already known salt bridge interaction between K28 and D23, our analyses expose more significant role of K28 as the only positive charge present in the vicinity. Amongst the two consecutive aromatic residues, F19 is involved in stacking interaction; although effect of F20 mutation is more pronounced. Face to face arrangement of A21 and V36 acts as a pillar maintaining the necessary optimum distance between consecutive chains to promote stabilizing interactions. In addition to providing stability to the first beta-strand, large sized negatively charged E22 facilitates salt bridge formation by ensuring fixed relative position of D23 and in turn K28. Likewise, the hydrophobic residues I32 and L34 pack the protofibril core, once again fostering salt bridge interaction. Prospectively, these findings may be compiled for efficient identification or design of scaffolds accountable for protofibril destabilization.Communicated by Ramaswamy H. Sarma.
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  • 文章类型: Journal Article
    We present the results of an experimental and computational study of structural changes in two polymorphs of tolazamide {systematic name: 1-[(azepan-1-ylamino)carbonyl]-4-methylbenzenesulfonamide}, C14H21N3O3S, on cooling to 100 K and reverse heating. No phase transitions occurred in this temperature range. The anisotropy of the thermal expansion was different for the two polymorphs and differed from that reported previously for the hydrostatic compression. The changes in different intermolecular contacts responsible for the strain anisotropy were analysed. Relative shortening of the contacts was related directly to their initial length and reversely to the steric density around them. Increasing steric density is likely to be the driving force for the conformational ordering of the azepane ring under compression.
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  • 文章类型: Journal Article
    The reaction pathway of the cyclization of 2-phenoxybenzophenone into 9-phenyl-9H-xanthen-9-ol in the presence of acid and an excess of AlCl33 was studied using density functional theory. This type of reaction is known to occur during the Friedel-Crafts polycondensation of poly(aryl ether ketones) following the undesired benzoylation of nucleophilic positions ortho- to the growing polymer\'s ether groups. The formed defect acts as an undesired terminator of the polymer chain, causing severe problems in the polymer\'s melt state. A branched, multistep mechanism reminiscent of the Friedel-Crafts acylation reaction is discovered; the reaction starts with the protonation of the carbonyl oxygen, followed by intramolecular electrophilic attack on the carbonyl carbon that determines the turnover frequency of the catalytic cycle and ends by deprotonation of the Wheland intermediate.
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  • 文章类型: Journal Article
    在过去的几年里,一些作者专注于通过毛细管电泳表征纳米粒子的大小和电荷。然而,考虑到纳米颗粒通常悬浮在不同于通常用作背景电解质(BGE)的溶剂中,需要对样品-BGE界面中纳米颗粒的行为进行适当的表征,因为这可能会影响纳米粒子的整体电泳行为。在目前的工作中,我们致力于评估COOH包覆的磁赤铁矿纳米颗粒在pH边界附近的行为。要做到这一点,将在酸性介质中制备的纳米颗粒的不同悬浮液注射到硼酸盐/NaOHpH9.5BGE中。通过计算机模拟对此类系统中样品-BGE界面中边界的形成和演化进行了建模。对共离子等参数的影响进行系统评估,样品的pH值或注入时间对纳米粒子的电泳行为进行了研究。
    During the last years, several authors have focused on the characterization of the size and charge of the nanoparticles by capillary electrophoresis. However, considering that nanoparticles are generally suspended in a solvent different from those commonly used as background electrolytes (BGE), an appropriate characterization of the behavior of the nanoparticles in the sample-BGE interface is required, as this might affect the overall electrophoretic behavior of the nanoparticles. In the present work, we address the evaluation of the behavior of COOH-coated maghemite nanoparticles in the vicinity of a pH boundary. To do so, different suspensions of nanoparticles prepared in acid media were injected into a borate/NaOH pH 9.5 BGE. The formation and evolution of boundaries in the sample-BGE interface in such systems was modeled by computer simulation. A systematic evaluation of the effect that parameters such as the co-ion, the sample pH or the injection time have on the electrophoretic behavior of the nanoparticles was carried out.
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