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The objectives of this study were to show the effect of miR-222 expression on angiogenesis and the mechanism of angiogenesis differentiation of bone microvascular endothelial cells. For the study, the concentration of VEGF release was detected by ELISA, and cell activity was shown using a CCK-8 (Cell Counting Kit-8). We used western blotting to detect VEGFR, TGF-β, and bFGF expression. The results showed that miR-222 expression by day 14 was significantly lower compared to the expression results for days 3 and 7. Additionally, miR-222 expression on day 7 was significantly lower than on day 3. MiR-222 expression in the control group and PELA group decreased gradually over time. On day 14, miR-222 expression in the VEGF microcapsule scaffold group was at its lowest level. Our conclusions were that the regulation of the angiogenesis of bone microvascular endothelial cells appears to be related to (1) the effect of miR-222 on VEGFR and TGF-β, and (2) how bFGF expression is regulated.

In 2015, China National Energy Administration announced an action plan of 2 trillion yuan ($3225.8 billion) investment for power distribution network for the coming 5 years. The intent is to upgrade and modernise the network to meet multidimensional requirements, including distributed energy resources, high levels of security, quality and efficiency of power supply, and requests of CO 2 reduction. A systematic, effective reform action would best be based on the comprehensive evaluation of network performance. However, in literature, previous works evaluated intensively on partial network performances, i.e. reliability, operation efficiency etc. Different from these approaches, this study proposes a holistic performance evaluation framework based on health index (HI) methodology. To cope fully with industry needs, the proposed HI system measures performances of two-level objects from power equipment to network scales. For each level, the corresponding HI is derived successively by determining object's health metrics, establishing a core set of indicators, building physics-based model, using data-driven and multiple health information fusion techniques. As part of a 3-year major research programme initiated by State Grid of China, the above work has been implemented in a software architecture. The fundamentals of distribution network HI framework are reported and discussed.

SCADA collects a large amount of alarm information during the power system operation. If the controller cannot quickly judge the monitoring alarm events, it may cause the expansion of the accident. Therefore, we propose a grid monitoring alarm event recognition method combining expert rules and deep learning. The method includes two stages: expert knowledge base determination and deep learning recognition model determination. In the first stage, the characteristics and rules related to monitoring alarm events are sorted, the expert knowledge base is constructed, and the alarm events are initially identified. In the second stage, the preliminary judgment results and the alarm information are combined into the convolutional neural network (CNN) recognition model, thus the final recognition result is obtained.

Alarm messages for grid monitoring are an important way to supervise the operation of power grids. Since the use of alarm messages is increasing exponentially due to the continuous expansion of the scale of power grids, a processing method for alarm messages based on statistics is proposed in this study. Entropy theory in information theory is introduced into the calculation of information value in power-grid alarming. By means of multiple entropy definitions, an evaluation index system for information value is constructed. Based on the analytic hierarchy process (AHP), various alarm-message entropies are used as indices to comprehensively assess the information value and level of each alarm message. Finally, an example is given to illustrate the effectiveness and practicality of the proposed method. This study provides a new idea for the intelligent classification of alarm messages.

Large scale integration of intermittent renewable energy sources, responsive loads and energy storage devices in distribution network has brought great challenges to operation in power systems, especially under fault condition. To cope with the requirement of reliability of the distribution network, distributed feeder automation (FA) is utilized, and the performance of it is high relied on the accuracy of the system model. In this paper, a verification algorithm is introduced to check the model from smart terminal unit (STU) and master station to enhance the reliability of distributed FA. The algorithm utilized MD5 message-digest algorithm and consensus algorithm to generate the "finger print" of the model to be compared with each other. Thus, the comparison can be achieved by communication between the master station and only one STU, which greatly simplifies the verification procedure and increase its speed. And the application of this algorithm is also given in the paper.

The reduction of common mode leakage current in centralized inverter for grid-connected PV (photovoltaic) system has been well studied. However, the research in cascaded multilevel inverter PV system is not far enough. This paper focuses on analyzing the generation mechanism of common mode leakage current and building equivalent circuit model of cascaded PV system. By clarifying the reason why the conventional cascaded H4 (full-bridge inverter) PV system fails to reduce the common mode leakage current, a new cascaded iH6 inverter PV system is proposed. The related theoretical analysis and simulation results are given, and it is verified that the common mode leakage current can be greatly reduced compared with the conventional cascaded H4 system. Meanwhile, the cascaded iH6 inverter PV system does not need an EMI filter to suppress the high frequency noise.

Cable conductor temperature is the key condition to determine whether current in operation reaches to cable's ampacity. In order to optimize cable operation, it is important to calculate cable conductor temperature with high accuracy. A simple and quick method of calculating temperature field for double-circuit underground cables is introduced in this paper. The superpose principle is applied to establish a calculation model of conductor temperature, and the conductor temperature is divided into three parts: initial temperature decided by environment temperature, temperature rise caused by its loss, and conductor temperature rise generated by other cable heat sources. Theoretical calculating models are established by combinating analytical method and the finite element method, then the formula of conductor temperature is deduced. On this basis, double-circuit soil buried cables' ampacity is calculated and optimized. Finally, the validity of conductor temperature field model and calculation formula proposed in this paper is verified by calculation examples.

Under the background of steady development of DC transmission and distribution technology, a series of pilot projects and demonstrations have been carried out gradually in the Engineering application of DC distribution network. In this paper, the typical mode of low voltage DC distribution network- flexible distribution system, is taken as the main research object. The interface between low voltage DC distribution and AC distribution, the distributed energy resource and electric vehicle, and the characteristics of electrical load is considered synthetically. The DC voltage level, power supply radius and capacity, the mode of grounding and connection, and topology structure are analyzed and studied. The typical DC distribution structure is analyzed by simulation. And the DC network load mutual supply experiment system suitable for different scenarios is constructed.

There are many uncertain factors in the modern distribution network, including the access of renewable energy sources and the heavy load level. The existence of these factors has brought challenges to the stability of the power distribution network, as well as increasing the risk of exceeding transmission capacity of distribution lines. The appearance of flexible load control technology provides a new idea to solve the above problems. Air conditioners (ACs) account for a great proportion of all loads. In this paper, the model of dispatching AC loads in the regional power grid is constructed, and the direct load control (DLC) method is adopted to reduce the load of ACs. An improved tabu search technique is proposed to solve the problem of network dispatch in distribution systems in order to reduce the resistive line losses and to eliminate the transmission congestion in lines under normal operating conditions. The optimal node solution is obtained to find the best location and reduction capacity of ACs for load control. To demonstrate the validity and effectiveness of the proposed method, a test system is studied. The numerical results are also given in this article, which reveal that the proposed method is promising.

Due to the presence of urban heat island effect (UHIE), high humidity and other urban microclimate, temperature of city central area rises. This causes that the actual air-conditioning energy consumption (ACEC) in the urban central area is much higher than that in the suburbs. Load control of air-conditioners (ACs) is considered to be equivalent to a power plant of the same capacity, and it can greatly reduce the system pressure to peak load shift. In this paper, a simplified second order transfer function control model of ACs is presented, and its parameters will be influenced by the ambient temperature and urban microclimate. The temperature is obtained by using the temperature inversion algorithm of the heat island effect. Then, the heat index is calculated by combining temperature and humidity. The ambient temperature index of urban central area is modified based on the above microclimate, and the second order linear time invariant model of aggregated ACs is upgraded to the linear time varying model. Furthermore, the consequent parameter changes of the second order transfer function model are studied and the influence of urban microclimate on AC load control is analyzed. The proposed method is verified on numerical examples