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关键词： COVID-19   Influenza   Cytokines   SARS-CoV-2   Obesity  

摘要： Severe COVID-19 is marked by dysregulated inflammation and is associated with elevated BMI. By comparing cytokines and chemokines in patients with either COVID-19 or influenza, we identified distinct inflammatory pathways and a cytokine mediator of the effect of BMI. Background Several inflammatory cytokines are upregulated in severe coronavirus disease 2019 (COVID-19). We compared cytokines in COVID-19 versus influenza to define differentiating features of the inflammatory response to these pathogens and their association with severe disease. Because elevated body mass index (BMI) is a known risk factor for severe COVID-19, we examined the relationship of BMI to cytokines associated with severe disease. Methods Thirty-seven cytokines and chemokines were measured in plasma from 135 patients with COVID-19, 57 patients with influenza, and 30 healthy controls. Controlling for BMI, age, and sex, differences in cytokines between groups were determined by linear regression and random forest prediction was used to determine the cytokines most important in distinguishing severe COVID-19 and influenza. Mediation analysis was used to identify cytokines that mediate the effect of BMI and age on disease severity. Results Interleukin-18 (IL-18), IL-1 beta, IL-6, and tumor necrosis factor-alpha (TNF-alpha) were significantly increased in COVID-19 versus influenza patients, whereas granulocyte macrophage colony-stimulating factor, interferon-gamma (IFN-gamma), IFN-lambda 1, IL-10, IL-15, and monocyte chemoattractant protein 2 were significantly elevated in the influenza group. In subgroup analysis based on disease severity, IL-18, IL-6, and TNF-alpha were elevated in severe COVID-19, but not in severe influenza. Random forest analysis identified high IL-6 and low IFN-lambda 1 levels as the most distinct between severe COVID-19 and severe influenza. Finally, IL-1RA was identified as a potential mediator of the effects of BMI on COVID-19 severity. Conclusions These findings point to

关键词： 可分离变量微分方程   数学建模   思政元素   高等数学  

摘要： 本文以可分离变量微分方程章节的教学为例来探讨高等数学课程教学改革,在取得一些成效的同时,也存在一些问题.

摘要： One of the most prevalent malignant tumours is lung cancer. Circulating microRNAs (miRNAs) have shown to have significant promise for lung cancer diagnosis and prognosis, according to a growing body of research. The researchers wanted to explore if serum exosomal miR-1246 has any treatment significance in patients with non-small-cell lung cancer (NON-SCLC). Real-time PCR was used to determine the stage of exosomal miR-1246 serum expression in NON-SCLC patients. The researchers next looked into the link regarding exosomal miR-1246 serum stages and NON-SCLC prognosis. In NON-SCLC patients, exosomal miR-1246 serum appearance was considerably higher. According to a receiver operating characteristic (ROC) research, serum exosomal miR-1246 was effective in discriminating NON-SCLC patients from normal controls and non-malignant respiratory illness patients. Following treatment, the amount of serum exosomal miR-1246 reduced but increased in cases of recurrence. Furthermore, the level of serum exosomal miR-1246 was connected to distant metastases and TNM stages in a significant way. According to a survival analysis, cases with severe levels of exosomal miR-1246 serum had reduced overall or disease-free survival. The level of exosomal miR-1246 serum was found to be an autonomous predictive issue for NON-SCLC in multi-variate analysis. Finally, exosomal miR-1246 serum may be a useful prognosis biomarker for non-small-cell lung cancer.

关键词： x-ray phase contrast   edge illumination   Geant4  

摘要： The development of accurate simulation tools including x-ray phase-contrast effects is of great use in the design and optimization of x-ray phase-contrast imaging (XPCI) experimental setups. When the lateral coherence of the imaging system is limited, as in most compact laboratory-based XPCI applications, phase-contrast can be effectively described through refraction effects that can be simulated with a ray-tracing approach. This work presents a practical implementation of the x-ray phase-contrast in Geant4 and validates the simulation results against theoretical predictions for the propagation-based (PB) and edge-illumination (EI) imaging configurations. The simulation includes a realistic polychromatic tungsten anode spectrum and an extended x-ray source, a virtual phantom made of plastic wires with a diameter of 1 mm, as well as an accurate description of the absorbing masks and related movement during data acquisition. Results show a good agreement between theory and simulations, with maximum discrepancies below 2% in the intensity of PB images, below 0.3 mu rad for EI refraction, and below 0.03 mm for EI projected thickness. Additionally, an often disregarded effect such as the refraction sensitivity inhomogeneity across the field of view (around 20%) was reproduced by the simulation and quantitatively explained through a theoretical model. The presented simulation platform will be extensively used for the design of a novel EI facility that is under construction at the INFN laboratories in Trieste (Italy) in the framework of the Photon-counting Edge-illumination Phase-contrast Imaging (PEPI) project.

关键词： Gases  

摘要： Infrared matrix-assisted desorption and ionization (IR-MALDI) enables the transfer of sub-micron particles (sMP) directly from suspensions into the gas phase and their characterization with differential mobility (DM) analysis. A nanosecond laser pulse at 2940 nm induces a phase explosion of the aqueous phase, dispersing the sample into nano- and microdroplets. The particles are ejected from the aqueous phase and become charged. Using IR-MALDI on sMP of up to 500 nm in diameter made it possible to surpass the 100 nm size barrier often encountered when using nano-electrospray for ionizing supramolecular structures. Thus, the charge distribution produced by IR-MALDI could be characterized systematically in the 50-500 nm size range. Well-resolved signals for up to octuply charged particles were obtained in both polarities for different particle sizes, materials, and surface modifications spanning over four orders of magnitude in concentrations. The physicochemical characterization of the IR-MALDI process was done via a detailed analysis of the charge distribution of the emerging particles, qualitatively as well as quantitatively. The Wiedensohler charge distribution, which describes the evolution of particle charging events in the gas phase, and a Poisson-derived charge distribution, which describes the evolution of charging events in the liquid phase, were compared with one another with respect to how well they describe the experimental data. Although deviations were found in both models, the IR-MALDI charging process seems to resemble a Poisson-like charge distribution mechanism, rather than a bipolar gas phase charging one.

关键词： acoustic cloaking   partial differential equation-constrained optimization   metamaterial design  

摘要： We develop an optimization framework for the design of acoustic cloaks, with the aim of overcoming the limitations of usual transformation-based cloaks in terms of microstructure complexity and shape arbitrarity of the obstacle. This is achieved by recasting the acoustic cloaking design as a nonlinear optimal control problem constrained by a linear elliptic partial differential equation. In this setting, isotropic material properties' distributions realizing the cloak take the form of control functions and a system of the first-order optimality conditions is derived accordingly. Such isotropic media can then be obtained in practice with simple hexagonal lattices of inclusions in water. For this reason, the optimization problem is directly formulated to consider suitable partitions of the control domain. Two types of inclusions are analysed, and long-wavelength homogenization is used to define the feasible set of material properties that is employed as a constraint in the optimization problem. In this manner, we link the stage of material properties optimization with that of microstructure design, aiming at finding the optimal implementable solution. The resulting cloak is numerically tested via coupled structural/acoustic simulations. As a further test benchmark, a concave target and the silhouette of a ship are considered other than the usual axisymmetric cloak.

关键词： Stochastic functional differential equations with infinite delay   Non-Lipschitz conditions   Strong law of large numbers   Central limit theorem   Law of the iterated logarithm  

摘要： This paper examines limit theorems for a class of stochastic functional differential equations with infinite delay. Under non-Lipschitz conditions, the strong law of large numbers and the central limit theorem for additive functionals of the segment processes are established by using limit theorems of uniform mixing Markovian processes. Under some dissipative assumptions, the law of iterated logarithm is also derived for additive functionals of such equations via a martingale difference sequence of square integrable martingales. (c) 2021 Elsevier Inc. All rights reserved.