Zn-Co metal organic frameworks coated with chitosand and Au nanoparticles for chemo-photothermal-targeted combination therapy of liver cancer

The toxic effects of chemotherapy drugs on normal tissues are still a major limiting factor in cancer treatment. In this paper, we report a metal-organic framework (Zn-Co ZIF) with chitosan-coated outer layer as a carrier for the drug adriamycin hydrochloride (DOX), a treatment for liver cancer, as a novel anti-cancer nanodrug-enhanced carrier. Gold nanoparticles, a good photothermal conversion agent, were combined with the target SH-RGD during surface functionalisation to prepare Zn-Co ZIF@DOX-CS-Au-RGD (ZD-CAR), a nanoplatform with good photothermal conversion properties and targeting for combined liver cancer therapy. ZD-CAR was developed after RGD accurately targeted the tumour and entered the tumour microenvironment (TME), it cleaves and releases the liver cancer therapeutic agent (DOX) in a weak acidic environment to effectively kill tumour cells. The metal skeleton cleavage releases Co2+, which catalyzes the production of oxygen from H2O2 to alleviate the tumour hypoxic environment. The dissolved oxygen could reach 14 mg/L after adding 80 mg/mL of ZD-CAR. Meanwhile, gold nanoparticles could convert light energy into heat energy under 808 NIR irradiation to induce local superheating and kill tumour cells. In summary, this study developed a nanoplatform that combines chemo-photothermal-targeted therapy. It has shown good therapeutic effeciency in cellular experiments and performance tests and has promising applications in anti-cancer therapy

A review of voltage sag control measures and equipment in power systems

In recent years, voltage sags are one of the most critical research issues in the field of power quality. With the all-embracing study of voltage sag mitigation measures and equipment, the classification of voltage sag mitigation measures and equipment is becoming more and more necessary. Reasonable classification methods not only can guide users to choose appropriate control measures and equipment, but also provide basis and research direction for new voltage sag control measures and equipment. Firstly, this study performs a detailed analysis of the current stage of voltage sag control measures and equipment, and proposes a classification method that divides the voltage sag control measures into three categories: the power supply side, the customer side and the equipment manufacturing company. Secondly, due to the difference between single power supply and dual power supply in voltage sag control equipment, this study proposes a classification method for voltage sag control equipment based on the number and type of power supply. Finally, in order to help users to select the voltage sag control equipment suitable for the actual situation, this paper summarizes the prevention and control ability of the main voltage sag control equipment

Analysis of fault current and overvoltage at the neutral point of ±800 kV High-Voltage DC converter transformer

In order to enhance the security of ±800 kV High-Voltage DC (HVDC) system, it is needed to consider and analyze the grounding mode of the neutral point of converter transformer. Different neutral grounding modes have different inhibitory effects on the current of transmission lines when faults occur, and also produce different overvoltages at the neutral point. Therefore, this paper first analyzes the influence of converter transformer on fault current and neutral point voltage in three cases of ungrounded, direct grounding and via small reactance grounding. Through the analysis, it is known that the neutral grounding via small reactance is the most suitable for the HVDC transmission system. Then the model of ±800 kV bipolar HVDC transmission system is built in PSCAD/ EMTDC simulation software and analyzed under two typical conditions of grounding overvoltage and breaking overvoltage. By comparing several cases of converter transformer neutral point grounding directly, via 5Ω, 10Ω, 17Ω, 20Ω and 25Ω reactance grounding, it is found that grounding via small reactance can effectively suppress fault current. However, with the increase of the resistance value, the inhibitory effect will gradually weaken and cause the increase of the neutral point overvoltage

sj-docx-1-ejo-10.1177_11206721241238878 - Supplemental material for Burdens and trends of blindness and vision loss among those aged 55 years and older: A systematic analysis for the Global Burden of Disease Study 2019

Supplemental material, sj-docx-1-ejo-10.1177_11206721241238878 for Burdens and trends of blindness and vision loss among those aged 55 years and older: A systematic analysis for the Global Burden of Disease Study 2019 by Congling Zhao, Qiang Ding and Zhikuan Yang in European Journal of Ophthalmology</p

Joint expansion planning of distribution network with uncertainty of demand load and renewable energy

Rational planning plays a key role in developing and improving operation security and stability of distribution networks (DNs). This paper proposes a novel method to solve the expansion of transmission lines (TLs) and the allocation of distributed generators (DGs) considering the uncertainty of load demand and renewable energy. The spanning-tree is a theoretical method specifically tailored to guarantee the radiality operation of distribution networks. Also, to guarantee the stability and reliability of the network, the probability function is used to describe the stochastic nature of load behavior and renewable sources fluctuation. Thus, the most proper installation location and time for TL and DG assets can be identified by modeling the joint expansion planning. The objective of the proposed model is minimizing the present value of the total social costs, including the cost of investment, purchasing energy, and environmental benefits. This mixed-integer nonlinear problem (MINLP) optimization model is solved based on GAMS environment. The effectiveness and scalability of this model is validated and illustrated based on the IEEE RTS-24 system

Accurate Peer-to-Peer Hierarchical Control Method for Hybrid DC Microgrid Clusters

Hybrid DC microgrid clusters contain various types of converters such as BOOST, BUCK, and bidirectional DC/DC converters, making the control strategy complex and difficult to achieve plug-and-play. The common master–slave hierarchical control strategy makes it difficult to achieve accurate and stable system control. This paper proposes an accurate peer-to-peer hierarchical control method for the hybrid DC microgrid cluster, and the working principle of this hierarchical control method is analyzed in detail. The microgrid cluster consists of three sub-microgrids, where sub-microgrid A consists of three BUCK converters, sub-microgrid B consists of three BOOST converters, and sub-microgrid C consists of two bidirectional DC/DC converters. According to all possible operations of various sub-microgrids in the microgrid cluster, the top-, mid-, and bottom-level controls are designed to solve the coordination control problem among different types of sub-microgrids. In this paper, a hybrid microgrid cluster simulation model is built in the PLECS simulation environment, and an experimental hardware platform is designed. The simulation and experiment results verified the accuracy of the proposed control strategy and its fast plug-and-play regulation ability for the system