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Dysregulation of MOF (also known as MYST1, KAT8), a highly conserved H4K16 acetyltransferase, plays important roles in human cancers. However, its expression and function in esophageal squamous cell carcinoma (ESCC) remain unknown. Here, we report that MOF is highly expressed in ESCC tumors and predicts a worse prognosis. Depletion of MOF in ESCC significantly impedes tumor growth and metastasis both in vitro and in vivo, whereas ectopic expression of MOF but not catalytically inactive mutant (MOF-E350Q) promotes ESCC progression, suggesting that MOF acetyltransferase activity is crucial for its oncogenic activity. Further analysis reveals that USP10, a deubiquitinase highly expressed in ESCC, binds to and deubiquitinates MOF at lysine 410, which protects it from proteosome-dependent protein degradation. MOF stabilization by USP10 promotes H4K16ac enrichment in the ANXA2 promoter to stimulate ANXA2 transcription in a JUN-dependent manner, which subsequently activates Wnt/β-Catenin signaling to facilitate ESCC progression. Our findings highlight a novel USP10/MOF/ANXA2 axis as a promising therapeutic target for ESCC.

Hexavalent chromium Cr(VI), as a well-established carcinogen, contributes to tumorigenesis for many human cancers, especially respiratory and digestive tumors. However, the potential function and relevant mechanism of Cr(VI) on the initiation of esophageal carcinogenesis are largely unknown. Here, immortalized human esophageal epithelial cells (HEECs) were induced to be malignantly transformed cells, termed HEEC-Cr(VI) cells, via chronic exposure to Cr(VI), which simulates the progress of esophageal tumorigenesis. In vitro and in vivo experiments demonstrated that HEEC-Cr(VI) cells obtain the ability of anchorage-independent growth, greater proliferative capacity, cancer stem cell properties, and the capacity to form subcutaneous xenografts in BALB/c nude mice when compared to their parental cells, HEECs. Additionally, HEEC-Cr(VI) cells exhibited weakened cell motility and enhanced cell adhesion. Interestingly, HEECs with acute exposure to Cr(VI) failed to display those malignant phenotypes of HEEC-Cr(VI) cells, suggesting that Cr(VI)-induced malignant transformation, but not Cr(VI) itself, is the cause for the tumor characteristics of HEEC-Cr(VI) cells. Mechanistically, chronic exposure to Cr(VI) induced abnormal activation of Notch signaling, which is crucial to maintaining the capacity for malignant proliferation and stemness of HEEC-Cr(VI) cells. As expected, N-[N-(3,5-difluorophenacetyl)-l-alanyl]-S-phenylglycine t-butyl ester (DAPT), an inhibitor for the Notch pathway, drastically attenuated cancerous phenotypes of HEEC-Cr(VI) cells. In conclusion, our study clarified the molecular mechanism underlying Cr(VI)-induced esophageal tumorigenesis, which provides novel insights for further basic research and clinical therapeutic strategies about Cr(VI)-associated esophageal cancer.

Purpose: Hyperspectral imaging has the potential to improve intraoperative decision making if tissue characterisation is performed in real-time and with high-resolution. Hyperspectral snapshot mosaic sensors offer a promising approach due to their fast acquisition speed and compact size. However, a demosaicking algorithm is required to fully recover the spatial and spectral information of the snapshot images. Most state-of-the-art demosaicking algorithms require ground-truth training data with paired snapshot and high-resolution hyperspectral images, but such imagery pairs with the exact same scene are physically impossible to acquire in intraoperative settings. In this work, we present a fully unsupervised hyperspectral image demosaicking algorithm which only requires exemplar snapshot images for training purposes. Methods: We regard hyperspectral demosaicking as an ill-posed linear inverse problem which we solve using a deep neural network. We take advantage of the spectral correlation occurring in natural scenes to design a novel inter spectral band regularisation term based on spatial gradient consistency. By combining our proposed term with standard regularisation techniques and exploiting a standard data fidelity term, we obtain an unsupervised loss function for training deep neural networks, which allows us to achieve real-time hyperspectral image demosaicking. Results: Quantitative results on hyperspetral image datasets show that our unsupervised demosaicking approach can achieve similar performance to its supervised counter-part, and significantly outperform linear demosaicking. A qualitative user study on real snapshot hyperspectral surgical images confirms the results from the quantitative analysis. Conclusion: Our results suggest that the proposed unsupervised algorithm can achieve promising hyperspectral demosaicking in real-time thus advancing the suitability of the modality for intraoperative use.

ABSTRACTHyperspectral imaging is one of the most promising techniques for intraoperative tissue characterisation. Snapshot mosaic cameras, which can capture hyperspectral data in a single exposure, have the potential to make a real-time hyperspectral imaging system for surgical decision-making possible. However, optimal exploitation of the captured data requires solving an ill-posed demosaicking problem and applying additional spectral corrections. In this work, we propose a supervised learning-based image demosaicking algorithm for snapshot hyperspectral images. Due to the lack of publicly available medical images acquired with snapshot mosaic cameras, a synthetic image generation approach is proposed to simulate snapshot images from existing medical image datasets captured by high-resolution, but slow, hyperspectral imaging devices. Image reconstruction is achieved using convolutional neural networks for hyperspectral image super-resolution, followed by spectral correction using a sensor-specific calibration matrix. The results are evaluated both quantitatively and qualitatively, showing clear improvements in image quality compared to a baseline demosaicking method using linear interpolation. Moreover, the fast processing time of 45 ms of our algorithm to obtain super-resolved RGB or oxygenation saturation maps per image for a state-of-the-art snapshot mosaic camera demonstrates the potential for its seamless integration into real-time surgical hyperspectral imaging applications.

Purpose: Management of vestibular schwannoma (VS) is based on tumour size as observed on T1 MRI scans with contrast agent injection. The current clinical practice is to measure the diameter of the tumour in its largest dimension. It has been shown that volumetric measurement is more accurate and more reliable as a measure of VS size. The reference approach to achieve such volumetry is to manually segment the tumour, which is a time intensive task. We suggest that semi-automated segmentation may be a clinically applicable solution to this problem and that it could replace linear measurements as the clinical standard. Methods: Using high-quality software available for academic purposes, we ran a comparative study of manual versus semi-automated segmentation of VS on MRI with 5 clinicians and scientists. We gathered both quantitative and qualitative data to compare the two approaches; including segmentation time, segmentation effort and segmentation accuracy. Results: We found that the selected semi-automated segmentation approach is significantly faster (167 s vs 479 s, $p\<0.001$\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$p<0.001$$\end{document}), less temporally and physically demanding and has approximately equal performance when compared with manual segmentation, with some improvements in accuracy. There were some limitations, including algorithmic unpredictability and error, which produced more frustration and increased mental effort in comparison with manual segmentation. Conclusion: We suggest that semi-automated segmentation could be applied clinically for volumetric measurement of VS on MRI. In future, the generic software could be refined for use specifically for VS segmentation, thereby improving accuracy.

Water always occurs in gas shales, especially during the treatment of shale gas hydraulic fracturing. In sharp contrast to the prevailing view that water film is ubiquitous in shale formations, we observed an unusual phenomenon that water bridge instead of water film dominates in some illite and kaolinite slit pores when we are investigating the coexisting pattern of water and methane inside shale nanopores using molecular dynamics simulations. The network orientation structure and hydrogen bond of water molecules are analyzed, and the results indicate that appearance of water bridge is attributed to the strong internal, self-generated electric field induced by surface charge contrast between different pore surfaces. Four factors can significantly influence this self-generated electric field strength: pore surface chemistry, mineral type, pore shape, and pore size. When the pore size is within several nanometers, a small charge difference could induce strong electric field and change the structural properties of water clusters. The water film or water bridge inside shale nanopores alters the hydraulic diameter of the pore and the fluid flow pattern. These findings may provide a better and microscopic insight of the water–gas flow behavior and the electric field inside clay nanopores.

It is particularly important to analyze the heat generation associated with the electrochemical process for thermal and safety management of ternary NMC lithium-ion batteries. In this paper, we develop an electrochemical-thermal coupled model to analyze the respective heat generation mechanisms of each battery component at both normal temperature and subzero temperature at different discharge rates. Taking 1C discharge rate as an example, at normal temperature the NE (negative electrode) heat generation rate is less than the PE (positive electrode) one. Although the NE polarization heat is higher than the PE one, there exists a large portion of reversible heat generation at PE as against a small portion at NE, leading to a lower level of heat generation at the NE. In addition, the transient heat generation rate of the NE keeps increasing with the discharge process and exceeds the PE one near the end of discharge. However, the NE heat generation rate at subzero temperature is much increased compared with the normal temperature case whereas the PE one changes little with temperature. The total NE heat generation rate at subzero temperature is higher than the PE one in that the NE polarization heat is much higher than the PE counterpart. It is noted that the polarization heat of the NE and PE is much higher than the ohmic heat throughout the temperature range. At the subzero temperature of −15 °C, the battery still functions at low to moderate discharge rates of 1– 1.5C by experiencing a voltage rebound without significant losing in capacity. The reversible heat occurring at NE exhibits heat release in the early stage of the discharge process at subzero temperature instead of heat absorption at normal temperature. In addition, the experimental test was also conducted to validate the present electrochemical and thermal coupled model.

Numerical simulation is performed for sessile droplet spreading and penetration on porous surfaces in this study. The volume of the fluid model is used to accurately track the droplet deformation, and the pressure implicit split operator algorithm is presented to calculate the coupling of the droplet pressure and velocity. The effects of droplet characteristics, porous media characteristics, and the wettability of liquid/porous media on sessile droplet spreading and permeation are investigated in detail. The studied problem can be characterized by four control parameters: the Bond number, Darcy number, static equilibrium contact angle, and ratio between the initial diameter of the droplet and the particle diameter in the porous substrate. The numerical simulations show that droplet spreading and penetration are competitive with each other and dependent on the above four dimensionless parameters. The results obtained in this work are of benefit to provide deep insights into the dynamic behavior of sessile droplet on porous substrates.

This paper numerically investigates the elastoplastic behavior and fatigue life of the current collector for the negative electrode of lithium-ion batteries (LIBs) based on the electrochemical-thermal-mechanical (ETM) coupling model. First, we discuss the effects of the thickness and yield stress of the current collector on the elastoplastic behavior. Then, we examine the influence of various current collector thicknesses on the stress in the active layer. Finally, the fatigue life of the current collector under different elastoplastic behaviors is predicted based on the Manson-Coffin-Basquin equation. The results indicate that the current collector will change from plastic shakedown (PS) to cyclic plasticity (CP) with decreasing current collector thickness or yield stress. Meanwhile, with the decrease of the current collector thickness, the peak stress in the current collector increases, while the stress level in the active layer decreases. The investigation of the fatigue life reveals that, the case of CP not only relieves the stress in the active layer but also provides more space (due to a thinner collector) for the active material to improve the energy density of the battery. The aforementioned studies shed light on the fatigue and elastoplastic behaviors of LIBs collectors.

The adsorption properties of methane (CH4) have a great influence on shale gas exploration and development. The surface chemistry characteristics of nanopores are key factors in adsorption phenomena. The clay pores in shale formations exhibit basal surface and edge surfaces (mainly as A and C chain and B chain surfaces in illite). Little research regarding CH4adsorption on clay edge surfaces has been carried out despite their distinct surface chemistries. In this work, the adsorption of CH4confined in nanoscale illite slit pores with basal and edge surfaces was investigated by grand canonical Monte Carlo and molecular dynamics simulations. The adsorbed phase density, adsorption capacity, adsorption energy, isosteric heat of adsorption, and adsorption sites were calculated and analyzed. The simulated adsorption capacity compares favorably with the available experimental data. The results show that the edge surfaces have van der Waals interactions that are weaker than those of the basal surfaces. The adsorption capacity follows the order basal surface > B chain surface > A and C chain surface. However, the differences of adsorption capacity between these surfaces are small; thus, edge surfaces cannot be ignored in shale formation. Additionally, we confirmed that the adsorbed phase has a thickness of approximately 0.9 nm. The pore size determines the interaction overlap strength on the gas molecules, and the threshold value of the pore size is about 2 nm. The preferential adsorption sites locate differently on edge and basal surfaces. These findings could provide deep insights into CH4adsorption behavior in natural illite-bearing shales.

The diffusion process of lithium-ions in the positive electrode solid phase as within the liquid phase is one of the pivotal factors in determining the battery performance. The effective conductivity and diffusion coefficient of the solid and liquid phases can be regulated by changing the distribution of the volume fraction of active material and porosity on the positive electrode. These crucial parameters can affect the transfer of lithium-ions in the solid and liquid phases and ultimately affect the battery’s performance. In this paper, a pseudo-three-dimensional (P3D) electrochemical-thermal-mechanical (ETM) coupling model is employed to study the non-uniform porosity of the positive electrode, especially the effect of porosity variation on the battery temperature and stress during the discharge process. Through numerical results, we find that reasonable porosity distribution can make the electrode lithiation more uniform and reduce the battery surface temperature by decreasing ionic ohmic heat. In addition, we display the stress distribution on the electrode and inside the active particles after adopting the linear porosity. The results are helpful for an in-depth understanding of the effect of the non-uniform porosity of the positive electrode on the lithium transport mechanism, the stress mechanism, and the thermal mechanism during the operation of lithium-ion batteries (LIBs).

In this paper, a generalized pseudo three-dimensional (P3D) electrochemical-thermal-mechanical coupling (ETM) model is proposed to describe the multiphysics coupling behavior during the discharge of lithium-ion battery (LIB). The proposed model is established and simulated by using COMSOL Multiphysics. In particular, the influence of external loads on the LIB is investigated via the stress field where the particle scale is coupled with the representative volume element (RVE) scale. Moreover, dynamic parameters dependent on the temperature and the lithium concentration are introduced to enable the proposed model more physically realistic. We validate the model by comparing the numerical results with experimental data available in the literature. In addition, we find that the lithium concentration gradient is reduced by the stress effect inside the active particles. Then, we show the distributions of stress and lithium concentration in the electrodes during the discharge process. Finally, the effect of external loads on the electrochemical process is investigated. It indicates that the electrochemical reaction is promoted. The results are of benefit to obtain an in-depth understanding of the stress mechanism, the lithium transport mechanism, and the synergistic mechanism among the multiphysics fields during the operation of LIBs.

In the present work the effect of the power law exponent of power-law fluid and non-Darcy number of non-Darcy flow on stability of natural convection in porous media are studied. The computation analysis of effect of power-law exponent of power-law fluid and non-Darcy number of non-Darcy flow in the rectangular duct on the transition Rayleigh number Ra*, which means the convective model transiting from stationary state to periodic solution. The duct has filled a porous medium saturated with the power-law non-Newtonian fluid or Newtonian fluid for non-Darcy flow, in which there is uniform internal heat generation per unit volume q.In this paper the relationship between the transition Rayleigh number Ra* and the power-law exponent n, Ra* and non-Darcy number Be, are shown. To these two aspects, the transition route from steady to chaotic convection is also obtained.

Abstract A novel hybrid finite element approach using fundamental solutions in conjunction with the boundary integration is proposed for the analysis of axisymmetric elasticity problems. In the formulation two displacement fields are independently assumed within the element domain and at the element boundary, which combines the advantages of conventional finite and boundary element methods. The resulting system of algebraic equations is symmetric and positive definite, which reduces the spatial dimension of the problem by one. It offers great flexibility in generating the mesh with arbitrary higher-order elements. Firstly, the proposed approach is validated by the analytical solution of a thick-walled hollow cylinder. A good agreement is observed. Meantime, the optimal number and location of source points for fundamental solutions as well as sensitivity to mesh distortion are studied. Finally, two more numerical examples including a flange and a wheel are provided. Compared to ABAQUS, the proposed approach exhibits higher efficiency, better convergence rate and strong capability to capture geometric singularities. [ABSTRACT FROM AUTHOR]

This paper describes a new type of hybrid fundamental solution based finite element method (HFS-FEM) for analysis of axisymmetric potential problems in multiply connected domain. In this approach, two independent potential fields are assumed within the element domain and on its boundary respectively. The fundamental solutions are utilized as internal trial functions to construct the non-conforming intra-element potential field. And the inter-element continuity is enforced by the conforming frame potential field which is of the same form as in the conventional FEM. Then, the axisymmetric modified variational functional is employed to derive the HFS finite element formulation. Finally, three numerical examples are given to demonstrate the validity, high-efficiency and robustness of the proposed method. [ABSTRACT FROM AUTHOR]

A novel hybrid polygonal finite element is proposed for simulating the heat conduction in two-dimensional cellular materials based on the hybrid fundamental-solution-based finite element method (HFS-FEM). The proposed method assumes two independent temperature fields in the domain and boundary of the element, respectively. The intra-element temperature field is approximated by a combination of fundamental solutions satisfying the governing equation of the problem. The charge simulation method is introduced so that the required fundamental solution can be established for the domain with an arbitrarily-shaped hole. To satisfy the continuity condition between adjacent elements, a conforming frame temperature field is approximated by the conventional finite element interpolation functions. Combing two independent fields into the modified variational functional leads to the resultant finite element formulation avoiding the need for domain integration. Such boundary-type feature endows a great capability of constructing any polygonal element with different number of sides and makes a great flexibility in mesh generation. The accuracy and efficiency of HFS-FEM are demonstrated through three numerical examples which includes triangular, astroid and irregular hole elements. [ABSTRACT FROM AUTHOR]