Implicit Damping Iterative Algorithm to Solve Elastoplastic Static and Dynamic Equations

This paper presents an implicit damping iterative algorithm to simultaneously solve equilibrium equations, yield function, and plastic flow equations, without requiring an explicit expression of elastoplastic stiffness matrices and local iteration for “return mapping” stresses to the yield surface. In addition, a damping factor is introduced to improve the stiffness matrix conformation in the nonlinear iterative process. The incremental iterative scheme and whole amount iterative scheme are derived to solve the dynamical and static and dynamical elastoplastic problems. To validate the proposed algorithms, computation procedures are designed and the numerical tests are implemented. The computational results verify the correctness and reliability of the proposed implicit iteration algorithms

Construction of a landscape ecological network based on landscape ecological risk assessment: A case study of the resource-based city of Linfen

The changes in the landscape structure within resource-dependent urban areas is influenced by a confluence of factors, potentially resulting in a decreased landscape ecological quality and a heightened ecological vulnerability. Landscape ecological quality directly influences the flow and transmission of ecological functions, rendering it a pivotal consideration in the development of landscape ecological networks. In this study, an investigation was conducted utilizing land-use data spanning from 2005 to 2020, encompassing the city of Linfen in Shanxi Province, China. A landscape ecological risk assessment model was formulated to analyze the spatiotemporal attributes of landscape ecological risk during this timeframe. Acknowledging the underlying connection between ecosystem resilience and landscape ecological quality, the 2020 landscape ecological risk assessment served as the basis for the extraction of ecological source areas using the Minimum Spanning Tree with Path Algorithm (MSPA), and the corridors were established using the Minimum Cumulative Resistance (MCR) model. This framework facilitated the construction of a landscape ecological network, and the complex network analysis was employed to scrutinize the network’s topological properties. The regions within the study area exhibiting high and extremely high ecological risk displayed an initial increase followed by a subsequent decrease, culminating in an overall reduction in risk levels. The areas surrounding urban development and mining activities displayed relatively heightened risk levels, while the regions characterized by forests and grasslands experienced relatively lower risks. The shifts in risk within the study area were predominantly attributed to various factors, including mining activities, urban expansion, governmental policies, alterations in land-use types, and village migrations. Through the optimization of the landscape ecological network using edge addition strategies and a subsequent comparison of network robustness pre- and post-optimization, it was discerned that the edge addition strategy notably improved the efficiency of energy transfer and interconnectivity among network nodes. This ecological risk assessment model, in conjunction with the development of a prospective ecological network, lends a valuable theoretical support to the enhancement of landscape structure within resource-dependent urban areas and the establishment of comprehensive ecological security systems

Investigation of foodborne disease outbreaks caused by Vibrio parahaemolyticus in China’s Mainland from 2010 to 2020

ObjectiveTo obtain the occurrence time and regional distribution characteristics， place of occurrence， high-risk food and risk factors， the epidemiological characteristics of foodborne disease outbreaks caused by Vibrio parahaemolyticus from 2010 to 2020 in China’s Mainland was analyzed.MethodsThe data of foodborne disease outbreaks caused by Vibrio parahaemolyticus were collected from China disease outbreak surveillance system from 2010 to 2020 were analyzed statistically.ResultsFrom 2010 to 2020， a total of 1 772 outbreaks of foodborne diseases caused by Vibrio parahaemolyticus were reported， with a total of 27 212 cases， 5 944 hospitalized cases and 2 deaths. The peak time was from July to September. The incidence in developed areas （28.8 cases/million people） was higher than that in underdeveloped areas （8.2 cases/million people）， and the incidence in coastal areas （31.7 cases/million people） was higher than that in inland areas （9.2 cases/million people）. The main causes were aquatic food （61.2%） and meat （25.3%）. Hotels and restaurants accounted for 49.6% of the total. The main contamination links were incomplete cooking of aquatic food and raw and cooked cross-contamination of ready-to-eat meat and vegetable food.ConclusionIn order to reduce the risk of foodborne diseases caused by Vibrio parahaemolyticus， it is important to strengthen the supervision of processing and storage of aquatic food and meat in catering service places

Construction of a cross-species cell landscape at single-cell level.

Individual cells are basic units of life. Despite extensive efforts to characterize the cellular heterogeneity of different organisms, cross-species comparisons of landscape dynamics have not been achieved. Here, we applied single-cell RNA sequencing (scRNA-seq) to map organism-level cell landscapes at multiple life stages for mice, zebrafish and Drosophila. By integrating the comprehensive dataset of > 2.6 million single cells, we constructed a cross-species cell landscape and identified signatures and common pathways that changed throughout the life span. We identified structural inflammation and mitochondrial dysfunction as the most common hallmarks of organism aging, and found that pharmacological activation of mitochondrial metabolism alleviated aging phenotypes in mice. The cross-species cell landscape with other published datasets were stored in an integrated online portal-Cell Landscape. Our work provides a valuable resource for studying lineage development, maturation and aging

The Formation of Shapes: Interplay of Genes during Leaf Development Processes

Leaf shape, as one of the clearest manifestations of plant morphology, shows considerable variation owing to genetics and the environment. Leaf initiation occurs in the peripheral zone of the SAM and goes through the three overlapping phases of leaf primordium initiation, leaf dorsiventral development, and leaf marginal meristem establishment. Transcription factors, such as KNOX, WOX, and CUC; hormone-regulating genes, such as GA2ox, GA20ox, and PIN1; and miRNAs such as miR164/165 are tightly involved in leaf shaping through the generation of intricate cooperative networks in different temporal phases and specific tissue zones. Here, we briefly discuss the critical interplay occurring between certain genes and the pivotal role these play in the leaf developmental network and phytohormone regulation, including AS1/AS2–KNOX–GA20ox–GA, miR164–NAM/CUC–PIN1–auxin, and CUC–BAS1/CYP734A–BR, and we attempt to summarize several basic insights into the mechanisms of leaf shape regulation

Computer-aided design–computer-aided engineering associative feature-based heterogeneous object modeling

Conventionally, heterogeneous object modeling methods paid limited attention to the concurrent modeling of geometry design and material composition distribution. Procedural method was normally employed to generate the geometry first and then determine the heterogeneous material distribution, which ignores the mutual influence. Additionally, limited capability has been established about irregular material composition distribution modeling with strong local discontinuities. This article overcomes these limitations by developing the computer-aided design–computer-aided engineering associative feature-based heterogeneous object modeling method. Level set functions are applied to model the geometry within computer-aided design module, which enables complex geometry modeling. Finite element mesh is applied to store the local material compositions within computer-aided engineering module, which allows any local discontinuities. Then, the associative feature concept builds the correspondence relationship between these modules. Additionally, the level set geometry and material optimization method are developed to concurrently generate the geometry and material information which fills the contents of the computer-aided design–computer-aided engineering associative feature model. Micro-geometry is investigated as well, instead of only the local material composition. A few cases are studied to prove the effectiveness of this new heterogeneous object modeling method

The Analysis of Genes and Phytohormone Metabolic Pathways Associated with Leaf Shape Development in <i>Liriodendron chinense</i> via De Novo Transcriptome Sequencing

The leaf, a photosynthetic organ that plays an indispensable role in plant development and growth, has a certain ability to adapt to the environment and exhibits tremendous diversity among angiosperms. Liriodendron chinense, an ancestral angiosperm species, is very popular in landscaping. The leaf of this species has two lobes and resembles a Qing Dynasty Chinese robe; thus, leaf shape is the most valuable ornamental trait of the tree. In this work, to determine the candidate genes associated with leaf development in L. chinense, scanning electron microscopy (SEM) was employed to distinguish the developmental stages of tender leaves. Four stages were clearly separated, and transcriptome sequencing was performed for two special leaf stages. Altogether, there were 48.23 G clean reads in the libraries of the two leaf developmental stages, and 48,107 assembled unigenes were annotated with five databases. Among four libraries, 3118 differentially expressed genes (DEGs) were enriched in expression profiles. We selected ten DEGs associated with leaf development and validated their expression patterns via quantitative real-time PCR (qRT-PCR) assays. Most validation results were closely correlated with the RNA-sequencing data. Taken together, we examined the dynamic process of leaf development and indicated that several transcription factors and phytohormone metabolism genes may participate in leaf shape development. The transcriptome data analysis presented in this work aims to provide basic insights into the mechanisms mediating leaf development, and the results serve as a reference for the genetic breeding of ornamental traits in L. chinense

Overexpression of a Novel LcKNOX Transcription Factor from Liriodendron chinense Induces Lobed Leaves in Arabidopsis thaliana

Liriodendron chinense is a common ornamental tree that has attractive leaves, which is a valuable trait for use in landscape architecture. In this work, we aimed to identify the potential genes that control and regulate the development of L. chinense leaf lobes. Based on the transcriptome data for the leaf developmental stages we previously generated, two candidate genes were identified in this study. KNOTTED-LIKE HOMEOBOX(KNOX), encoding homeobox family proteins, play a large role in leaf lobe and leaf complexity regulation. Here, two full length KNOX genes from L. chinense were amplified and named LcKNOX1 and LcKNOX6 according to their sequence similarities with the respective Arabidopsis thaliana KNOX family genes. Overexpression vectors were constructed and subsequently transformed into wild type (WT) A. thaliana. Additionally, LcKNOX6 was expressed in tobacco leaves to examine its subcellular localization, and the 35S::LcKNOX6 transgenic A. thaliana leaf cells were imaged with the use of SEM. The expression of several genes that participate in KNOX gene regulation were validated by quantitative real-time PCR. The results show that LcKNOX1 produces almost the same phenotype as that found in WT A. thaliana. Notably, the LcKNOX6-1 lines presented deep leaf lobes that were similar to L. chinense leaf lobes. Two 35S::LcKNOX6 lines induced an abnormal growth phenotype whose seeds were abortive. In short, these results indicate that the LcKNOX6 gene might affect leaf development in A. thaliana and provide insights into the regulation of L. chinense leaf shaping