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BACKGROUND: Currently, chronic obstructive pulmonary disease (COPD) significantly impacts patients’ quality of life and survival as it has a high morbidity and mortality rate. COPD progression is associated with infiltration of adaptive inflammatory immune cells that form lymphatic follicles into the lung. OBJECTIVE: The rapid development of single-cell RNA sequencing technology (scRNA-seq) provided us with powerful tools for studying the classification of cell subtypes. Additionally, it is known that COPD is closely related to the abnormal function of long-chain non-coding RNAs (lncRNAs), and scRNA-seq can help to study the expression of lncRNA from a single cell level. METHODS: We reanalyzed the scRNA-seq data of peripheral blood mononuclear cells of COPD patients downloaded from Gene Expression Omnibus (GEO) database, and performed the mRNA-based and lncRNA-based single cell clustering to compare the cell subsets in COPD and controls without COPD. Furthermore, we performed Gene Ontology (GO) enrichment analysis for the top ranked differentially expressed genes and target genes of differentially expressed lncRNAs in different cell subtypes for COPD and controls respectively. RESULTS: Differences in cell subtypes were found between COPD and controls. CONCLUSION: This study may help us to further understand the mechanism of the human adaptive immune cell response of COPD.

Bioelectricity plays a significant role in major biological processes and electrical stimulation is an effective and non-invasive way to promote cellular growth, differentiation and tissue regeneration. In tissue engineering, piezoelectric materials not only act as modulators to regulate behaviors and functions of cells and tissues, but are also used as scaffolds to regulate and guide cell growth and matrix synthesis, thus promoting the formation of new tissue. Piezoelectronic electrons are produced from piezoelectric materials upon mechanical stimuli and have similar effects on cells as an external electrical field. Devices based on piezoelectronics have been widely applied in bioelectronics and biomedical fields. In this review, the effects of piezoelectronic electrons on cells and their possible mechanisms are briefly introduced. Then, we overview the applications of piezoelectronic electrons in cell regulation and tissue regeneration according to the type of cells and tissues. Finally, future perspectives and challenges are also provided.

We consider the diffraction of an electromagnetic plane wave by a biperiodic structure. This paper is concerned with a numerical solution of the diffraction grating problem for three-dimensional Maxwell’s equations. Based on the Dirichlet-to-Neumann (DtN) operator, an equivalent boundary value problem is formulated in a bounded domain by using a transparent boundary condition. An a posteriori error estimate-based adaptive edge finite element method is developed for the variational problem with the truncated DtN operator. The estimate takes account of both the finite element approximation error and the truncation error of the DtN operator, where the former is used for local mesh refinements and the latter is shown to decay exponentially with respect to the truncation parameter. Numerical experiments are presented to demonstrate the competitive behaviour of the proposed method.

The perfectly matched layer (PML) method is extensively studied for scattering problems in homogeneous background media. However, rigorous studies on the PML method in layered media are very rare in the literature, particularly, for three-dimensional electromagnetic scattering problems. Cartesian PML method is favorable in numerical solutions since it is apt to deal with anisotropic scatterers and to construct finite element meshes. Its theories are more difficult than circular PML method due to anisotropic wave-absorbing materials. This paper presents a systematic study on the Cartesian PML method for three-dimensional electromagnetic scattering problem in a two-layer medium. We prove the well-posedness of the PML truncated problem and that the PML solution converges exponentially to the exact solution as either the material parameter or the thickness of PML increases. To the best of the authors’ knowledge, this is the first theoretical work on Cartesian PML method for Maxwell’s equations in layered media.

Given a shape regular tetrahedron and a curved surface that is defined implicitly by a nonlinear level set function and divides the tetrahedron into two sub-domains, a general-purpose, robust, and high-order numerical algorithm is proposed in this article for computing both volume integrals in the sub-domains and surface integrals on their common boundary. The algorithm uses a direct approach that decomposes 3D volume integrals or 2D surface integrals into multiple 1D integrals and computes the 1D integrals with Gaussian quadratures. It only requires finding roots of univariate nonlinear functions in given intervals and evaluating the integrand, the level set function, and the gradient of the level set function at given points. It can achieve arbitrarily high accuracy by increasing the orders of Gaussian quadratures, and it does not need extra a priori knowledge about the integrand and the level set function. The code for the algorithm is freely available in the open-source finite element toolbox Parallel Hierarchical Grid (PHG) and can serve as a basic building block for implementing 3D high-order numerical algorithms involving implicit interfaces or boundaries.