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Brassica parachinensis is a popular leafy vegetable. It is able to accumulate high concentration of Cd, however, the molecular mechanism of Cd accumulation is unknown. This study investigated the function and regulatory mechanism of the Cd-responsive metal ion transporter gene BrpHMA2. BrpHMA2 was induced by Cd stress and specifically expressed in vascular tissues, and the protein was localized in the plasma membrane. Heterologous expression of BrpHMA2 enhanced Cd accumulation and Cd sensitivity in transgenic Arabidopsis and yeast. After Cd stress, the transcriptional factors BrpNAC895 and BrpABI449, which may recognize the ABREs in the BrpHMA2 promoter, were also differentially expressed. The transcriptional regulation of BrpHMA2 was further investigated using ChIP-qPCR, EMSA and LUC reporter activity analysis employing the transient expression system of Brassica parachinensis protoplasts and tobacco leaves and the E. coli expression system. By binding to the promoter, BrpNAC895 induced the transcription of BrpHMA2. BrpABI449 might bind to the BrpHMA2 promoter or interact with BrpNAC895 to interfere with the action of BrpNAC895. The findings suggest that BrpHMA2 is a membrane-based afflux-type Cd transporter involved in the Cd2+ uptake and long-distance transport in plants. BrpNAC895 and BrpABI449, which function as the transcription activator and repressor respectively, coregulate BrpHMA2 expression.

Additional file 1: Fig. S1. Regional distribution, density distribution and principal component analysis of gene expression. Fig. S2. Hierarchical clustering DEGs in CS (LTvsNT). Each column represents a comparison group, and each row represents a gene. Fig. S3. qRT-PCR validation of expression profiles obtained by RNA-Seq in CT and CS under cold stress. Table S1. Summary of sequence assembly after illumine sequencing. Table S2. Number of reads sequenced and mapped to the Brassica rapa genome. Table S3. List of the core genes set involved in CS response to cold stress. Table S4. Top30 up GO enrichment analysis in CT(LTvsNT). Table S5. Top30 up GO enrichment analysis in CS(LTvsNT). Table S6. Primer pairs used to detect the expression of selected genes.

As a new industry, coal chemical industry is a high-risk industry with large investment scale, long process and complex technology. Its personnel come from coal mine, petroleum and petrochemical industry, and their quality and safety perception are different. Their behavior pattern has the characteristics of both coal mine and chemical industry, resulting in huge potential risk of personnel behavior. It is very important to study the safety behavior model of front-line workers under the management system of coal chemical industry. Based on the theory of planned behavior and the theory of prospect, this paper puts forward a model of safety behavior planning. In order to verify the model, the coal chemical front-line employees are taken as the research object. Firstly, through the comprehensive application of psychology, behavioral theory and previous research results of safety human factors, a more comprehensive index of safety factors on the spot is constructed, in which safety plan behavior elements are mixed. This paper explores the mechanism among many factors, collects index data through safety perception questionnaire, and uses DEMATEL-SIM system analysis method to analyze the system structure model of the influencing factors of field safety. The structure model supports the safety behavior planning model. Then the structural equation model is constructed to validate the safety behavior planning model, and the empirical research is carried out. The results show that there is a safety behavior planning model under the coal chemical management system, and the corresponding control countermeasures are given.

During grid faults, the grid-connected inverter (GCI) cannot work well by only using the traditional droop control. Besides, the unbalance factor of voltage/current at Common Coupling Point (PCC) may increase significantly. Therefore, in order to ensure GCI stable operation during grid fault, the GCI should integrate the ability to compensate for the imbalance of the grid. To solve the problem mentioned above, an improved voltage-type grid-connected control strategy is proposed in this paper. On the basis of the positive sequence power droop control, a negative sequence conductance compensation loop is added to keep the PCC voltage balance and reduce the grid current imbalance, thus meeting the PCC power quality requirements. Simulation and experimental results have verified the effectiveness of the improved droop control scheme.

In this paper, an improved control strategy for three-phase inverter is proposed, which ensures three-phase output voltage symmetry under unbalanced grid voltage. Firstly, the positive and negative sequence separation module is used to obtain unbalance output voltage and current during the grid faults. By calculating output power of the inverter, an improved P-ƒ, Q-U and Q-G droop control strategy is designed to adjust droop curve real-timely. Then three-phase symmetrical voltage reference could be generated. In order to improve the stability of parallel three-phase inverter system, the virtual impedance is further applied. The simulation results presented verify the feasibility of the improved control scheme. Experimental tests and analysis have been provided in this paper.