Scheme design considering network topology and multi-attribute decision-making for under frequency load shedding

Power system emergency control is one key defense strategy in contingencies for protecting the system from cascading blackout. Under Frequency Load Shedding (UFLS) is one such strategy to ensure system stability by shedding load to retrieve balance between power supply and demand. Novel UFLS scheme design and a scheme optimization approach are proposed in this paper to find the optimal load-shedding schemes for different network partition resulted from contingencies. To obtain all possible UFLS schemes for a certain area, a candidate scheme set design algorithm based on value assigning of scheme parameters is proposed and then a relatively complete candidate scheme set is constructed. Considering network splitting caused by protection, several subsystems may exist from the reconstruction of independent network areas. The concept of homological area is defined and a graph-based method is used to analyse system topology change. Then, a multi-attribute decision-making (MADM) algorithm is introduced for order preference by similarity to an ideal solution (TOPSIS) for global optimizing candidate schemes. Optimal schemes for an area in both isolated area and homological area cases can be derived from all feasible UFLS schemes by MADM method. Simulation results demonstrate that the UFLS schemes can effectively restore system frequency in different network topologies.     

变频节能技术在山煤国际澄蓉选煤厂的应用

随着国家对环保、节能降耗要求的提高,以重介工艺为主的选煤厂大力响应国家的环保政策,实现节能降耗。山煤国际能源澄蓉选煤厂对合格介质泵304(450 kW)、精磁泵328(200 kW)、中矸泵(90 kW)、浮选入料泵402(185 kW)、循环水泵604(200 kW)等大功率电机(占全厂总容量33.3%)采用美国圣诺变频器进行调控,仅电能一项每年就为公司节省了近200万元。采用变频器来控制大功率的泵类设备,还可以降低电机的噪音污染、减少管路阀门的机械磨损、延长泵的使用寿命,节省了人力和物力。     

煤炭装卸系统增设筛分设备的改造方法

在简单介绍煤炭专业化连续输送系统和煤炭筛分设备知识的基础上,结合天津港煤码头公司卸车系统筛分设备改造的相关内容,阐述了在传统煤炭连续输送系统中进行煤炭筛分设备改造的方法。     

Increasing X-ray image interpretation competency of cargo security screeners

X-ray screening of containers and unit load devices in the area of cargo shipping is becoming an essential and common feature at ports and airports all over the world. The detection of prohibited items in X-ray images is a challenging task for screening officers as they need to know which items are prohibited and what they look like in X-ray images. The main aim of this study was to investigate whether X-ray image interpretation competency of cargo security screeners can be increased by computer-based training. More specifically, effects of training were investigated by conducting tests before training started and after approximately three months of training. Moreover, it was examined whether viewing X-ray images in pseudo color would lead to a better detection performance compared to when X-ray images are shown in greyscale. Recurrent computer-based training resulted in large performance increases after three months. No significant difference in detection performance could be found for tests when using X-ray images in greyscale vs. pseudo color.     

Development of efficient docking strategies and structure-activity relationship study of the c-Met type II inhibitors

c-Met is a transmembrane receptor tyrosine kinase and an important therapeutic target for anticancer drugs. In the present study, we systematically investigated the influence of a range of parameters on the correlation between experimental and calculated binding free energies of type II c-Met inhibitors. We especially focused on evaluating the impact of different force fields, binding energy calculation methods, docking protocols, conformation sampling strategies, and conformations of the binding site captured in several crystallographic structures. Our results suggest that the force fields, the protein flexibility, and the selected conformation of the binding site substantially influence the correlation coefficient, while the sampling strategies and ensemble docking only mildly affect the prediction accuracy. Structure-activity relationship study suggests that the structural determinants to the high binding affinity of the type II inhibitors originate from its overall linear shape, hydrophobicity, and two conserved hydrogen bonds. Results from this study will form the basis for establishing an efficient computational docking approach for c-Met type II inhibitors design.     

NMR-Guided Repositioning of Non-Steroidal Anti-Inflammatory Drugs into Tight Junction Modulators

Bioavailability is a major bottleneck in the clinical application of medium molecular weight therapeutics, including protein and peptide drugs. Paracellular transport of these molecules is hampered by intercellular tight junction (TJ) complexes. Therefore, safe chemical regulators for TJ loosening are desired. Here, we showed a potential application of select non-steroidal anti-inflammatory drugs (NSAIDs) as TJ modulators. Based on our previous observation that diclofenac and flufenamic acid directly bound various PDZ domains with a broad specificity, we applied solution nuclear magnetic resonance techniques to examine the interaction of other NSAIDs and the first PDZ domain (PDZ1) of zonula occludens (ZO)-1, ZO-1(PDZ1). Inhibition of ZO-1(PDZ1) is expected to provide loosening of the epithelial barrier function because the domain plays a crucial role in maintaining TJ integrity. Accordingly, diclofenac and indomethacin were found to decrease the subcellular localization of claudin (CLD)-2 but not occludin and ZO-1 at the apicolateral intercellular compartment of Madin–Darby canine kidney (MDCK) II cells. These NSAIDs exhibited 125–155% improved paracellular efflux of fluorescein isothiocyanate insulin for the Caco-2 cell monolayer. We propose that these NSAIDs can be repurposed as drug absorption enhancers for peptide drugs.     

The Discovery of Aurora Kinase Inhibitor by Multi-Docking-Based Virtual Screening

We report the discovery of aurora kinase inhibitor using the fragment-based virtual screening by multi-docking strategy. Among a number of fragments collected from eMololecules, we found four fragment molecules showing potent activity (>50% at 100 μM) against aurora kinase. Based on the explored fragment scaffold, we selected two compounds in our synthesized library and validated the biological activity against Aurora kinase.     

A Conditionally Fluorescent Peptide Reporter of Secondary Structure Modulation

Proteins containing intrinsic disorder often form secondary structure upon interaction with a binding partner. Modulating such structures presents an approach for manipulating the resultant functional outcomes. Translational repressor protein 4E-BP1 is an example of an intrinsically disordered protein that forms an α-helix upon binding to its protein ligand, eIF4E. Current biophysical methods for analyzing binding-induced structural changes are low-throughput, require large amounts of sample, or are extremely sensitive to signal interference by the ligand itself. Herein, we describe the discovery and development of a conditionally fluorescent 4E-BP1 peptide that reports structural changes of its helix in high-throughput format. This reporter peptide is based on conditional quenching of fluorescein by thioamides. In this case, fluorescence signal increases as the peptide becomes more ordered. Conversely, destabilization of the α-helix results in decreased fluorescence signal. The low concentration and low volume of peptide required make this approach amenable for high-throughput screening to discover ligands that alter peptide secondary structure.     

Leaf-to-Whole Plant Spread Bioassay for Pepper and Ralstonia solanacearum Interaction Determines Inheritance of Resistance to Bacterial Wilt for Further Breeding

Bacterial wilt (BW) disease from Ralstonia solanacearum is a serious disease and causes severe yield losses in chili peppers worldwide. Resistant cultivar breeding is the most effective in controlling BW. Thus, a simple and reliable evaluation method is required to assess disease severity and to investigate the inheritance of resistance for further breeding programs. Here, we developed a reliable leaf-to-whole plant spread bioassay for evaluating BW disease and then, using this, determined the inheritance of resistance to R. solanacearum in peppers. Capsicum annuum ‘MC4′ displayed a completely resistant response with fewer disease symptoms, a low level of bacterial cell growth, and significant up-regulations of defense genes in infected leaves compared to those in susceptible ‘Subicho’. We also observed the spreading of wilt symptoms from the leaves to the whole susceptible plant, which denotes the normal BW wilt symptoms, similar to the drenching method. Through this, we optimized the evaluation method of the resistance to BW. Additionally, we performed genetic analysis for resistance inheritance. The parents, F₁ and 90 F₂ progenies, were evaluated, and the two major complementary genes involved in the BW resistance trait were confirmed. These could provide an accurate evaluation to improve resistant pepper breeding efficiency against BW.