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Targeting the problem of the power grid facing greater risks with the connection of large-scale wind power, a method for power grid state analysis using big data is proposed. First, based on the big data, the wind power matrix and the branch power matrix are each constructed. Second, for the wind energy matrix, the eigenvalue index in the complex domain and the spectral density index in the real domain are constructed based on the circular law and the M-P law, respectively, to describe the variation of wind energy. Then, based on the concept of entropy and the M-P law, the index for describing the variation of the branch power is constructed. Finally, in order to analyze the real-time status of the grid connected to large-scale wind power, the proposed index is combined with the sliding time window. The simulation results based on the enhanced IEEE-33 bus system show that the proposed method can perform real-time analysis on the grid state of large-scale wind power connection from different perspectives, and its sensitivity is good.

Carolyn K Kan,1 Muhammad M Qureshi,1 Munizay Paracha,2 Teviah E Sachs,3 Suzanne Sarfaty,2 Ariel E Hirsch1 1Department of Radiation Oncology, Boston Medical Center, Boston, MA, USA; 2Department of Medicine, Boston Medical Center, Boston, MA, USA; 3Department of Surgical Oncology, Boston Medical Center, Boston, MA, USACorrespondence: Ariel E HirschDepartment of Radiation Oncology, Boston Medical Center, Moakley Building, Lower Level, 830 Harrison Avenue, Boston, MA, 02118, USATel +1 617-638-7070Email Ariel.Hirsch@bmc.orgIntroduction: Understanding the trend of student authorship is crucial in determining its correlation to scholarly impact for corresponding authors. Our objective is to investigate student authorship rates over time in articles published in JAMA Internal Medicine (IM), as well as to examine potential effects student authors have on scholarly impact scores of corresponding authors via H-index measures.Methods: Authorship data including student authors (SA), first student authors, and corresponding authors (CA) from prior JAMA IM publications between 2010 and 2018 were collected, with a total of 701 studies. Analysis of variance (ANOVA) and independent sample t-tests were performed to assess for differences in the mean by publishing year and student authorship, respectively.Results: Of 4591 total authors, 683 (14.9%) were considered student authors. The percentage of student authorship increased from 46.3% to 58.0% between 2010 and 2018, respectively. No difference in average H-indices of CA between SA and non-SA groups (overall NSA Hi mean: 30.2, vs SA Hi mean: 32.1, p=0.371) was noted.Discussion: Student participation in research is not a disadvantage to scholarly impact for corresponding authors. Increased student authorship reflects a promising trend towards greater student participation in research within the field of medicine.Keywords: student research, medical student, academic productivity, H-index, authorship

Abstract Methylene blue (MB) is a century-old medicine, a laboratory dye, and recently shown as a premier antioxidant that combats ROS-induced cellular aging in human skins. Given MB’s molecular structure and light absorption properties, we hypothesize that MB has the potential to be considered as a sunscreen active for UV radiation protection. In this study, we tested the effects of MB on UVB ray-induced DNA double-strand breaks in primary human keratinocytes. We found that MB treatment reduced DNA damages caused by UVB irradiation and subsequent cell death. Next, we compared MB with Oxybenzone, which is the most commonly used chemical active ingredient in sunscreens but recently proven to be hazardous to aquatic ecosystems, in particular to coral reefs. At the same concentrations, MB showed more effective UVB absorption ability than Oxybenzone and significantly outperformed Oxybenzone in the prevention of UVB-induced DNA damage and the clearance of UVA-induced cellular ROS. Furthermore, unlike Oxybenzone, MB-containing seawater did not affect the growth of the coral species Xenia umbellata. Altogether, our study suggests that MB has the potential to be a coral reef-friendly sunscreen active ingredient that can provide broad-spectrum protection against UVA and UVB.

The demand for decarbonization calls for nearly 100% renewable electricity rising as the dominant power resource. The foregoing paradigm shifts require proactive voltage and frequency controllers for the converter-based renewable energy. This article proposed a novel grid-forming technique for voltage-source controlled photovoltaic (PV) operating in 100% renewable power systems. The proposed idea was to design a DC voltage collapse-prevention controller in conjunction with a simplified frequency and inertia controller, thereby smart capturing and releasing PV energy to achieve improvements in dynamic performance and efficiency. By setting the two-phase operation scheme, the model initiatively considers the conflict between frequency regulation and maximum power point tracking (MPPT) curve control. The preferred controls are validated using extensive simulation and experimental findings based on a semi-physical platform and a practical photovoltaic demonstration project. The proposed controller outperforms the standard PV current controller over a much larger range of weak grid situations, according to the experimental and engineering operational data. Results demonstrated the effectiveness of the presented method in applying to the future 100% renewable power system.

Recently, with the fast development of renewable energy, various power-electronic-based devices have been widely incorporated in power systems, and controller saturation limiters have been broadly utilized, such as in voltage-source converter. It has been well recognized that these saturation limiters make sustained oscillations possible. To study the impact of saturation limiters, by considering the dynamical response of double saturation limiters in both the d-axis and q-axis of the alternating current control, this paper establishes single-input-single-output models for two novel phenomena including the double-clipped oscillation and single-clipped oscillation, based on the describing function. Then the describing-function-based Nyquist criterion is used to obtain the amplitude and frequency of the sustained oscillations. The model accuracy is verified by the electromagnetic transient simulation, and the influences of control parameters are extensively studied. All these findings clearly demonstrate that the saturation limiters play an active role in sustained oscillations in power-electronic-based power systems.

During the black start, backup ac power sources such as diesel generators can offer line-side voltage reference for wind turbine and keep line-side converter of wind turbine work properly so that the dc-link capacitor voltage within converter can be established without overcharge. This study proposes a black start control strategy and line-side voltage establishment method for PMSG-based wind turbines with no ac power source. Unlike the traditional control strategy of full power grid-connected converters, the dc-link voltage within back-to-back full power converters of wind turbines can be controlled by generator-side converters, and the line-side voltage can be established by line-side converters with the help of fixed loads. The mechanical power can be balanced by pitch angle control, and the power unbalance between mechanical power and electrical power will be reflected in the rotor speed of PMSG. By this method, a single wind turbine can establish the line-side voltage with no extra backup ac power source, offering voltage reference for the other wind turbines during the black start of a wind power plant.

Over the past forty years of reform and opening up, the urban center system in the Pearl River Delta Region has been rapidly restructured. Its two central cities, Guangzhou and Shenzhen, have been fiercely competing in the field of economic development. Dealing with the functional positioning of the two cities has constituted a long-term concern for regional planning and policy making. Under the new circumstances of the Guangdong-Hong Kong-Macao Greater Bay Area, there is an urgent need to clarify the functional positioning of the two central cities of Guangzhou and Shenzhen. Further, there is a need to coordinate the relationship between competition and cooperation, the premise of which lies in the dynamic and accurate identification of urban functional characteristics. Previous studies directly used economic and industrial statistical data to study and analyze urban functions. However, due to the relative low frequency and high cost of data collection and analysis, it is difficult to carry out real-time analysis using these data. Based on the theoretical understanding of the projection of city functions to the city network, this article uses inter-city air passenger flow as its research medium. Further, it uses the air passenger flow data extracted from Baidu location-based services (LBS) big data. Taking the Chinese city network as its overall scope, it adopts the following two approaches. First, it compares the functional characteristics of the cities where the air passenger flows toward Guangzhou and Shenzhen are sourced. Second, it compares the functional characteristics of the employment places in the two megacities of Beijing and Shanghai, where the air passenger flows toward Guangzhou and Shenzhen are sourced. Therefore, the functional attributes and the functional areas of the source cities are used as the basis for identifying the comparative functional features of Guangzhou and Shenzhen to judge their overall functional characteristics in the Chinese urban network. The research results show the following. 1) First, compared with Shenzhen, Guangzhou's network connection with cities across China and Beijing and Shanghai focuses on administrative management and business functions. It plays the role of an administrative and business center within the spatial scale of the Pearl River Delta urban agglomeration. 2) Second, compared with Guangzhou, Shenzhen focuses on technological innovation, finance, and high-tech manufacturing functions, and plays the role of a technological innovation and financial center and high-tech manufacturing base under the scale of the Pearl River Delta. 3) Third, as the two major service industry centers in the Pearl River Delta region, Guangzhou focuses on public and general producer services, and Shenzhen focuses on advanced producer services such as finance and technological research and development. Shenzhen has a higher status within the Chinese urban network system based on the producer service industry. The method provided by this article, which involves locational big data to flexibly extract urban functional characteristics from the city network, is novel. Further, it can serve as a supplementary approach to the studies on urban functions which relied on traditional economic and industrial statistics. Meanwhile, the research results of this article provide evidence for deepening the theoretical understanding of the urban function-space-network mapping relationship.

Due to the high dependence of economic and social development on power systems, the demand for reliable operation of power systems is increasing. Considering the popularity and widespread installation of smart meters, accurate system/node reliability indexes can be obtained. The inverse problem of reliability evaluation (IPRE) refers to the use of known system/node reliability indexes to obtain component reliability parameters. In this paper, a novel method of solving the IPRE is proposed. First, based on a nonsequential Monte Carlo (NSMC) method, analytical expressions for system reliability indexes in terms of component reliability parameters are derived, and then, the nonlinear equations of the IPRE are constructed. Second, a high-order polynomial approximation based on the conjugate gradient algorithm is used to calculate the unknown component reliability parameters, and the results are compared with those obtained using traditional neural networks method. Finally, a continuation method is used to correct the errors of the obtained component reliability parameters. Three cases, namely, the IEEE 1979 Reliability Test System (IEEE RTS-79), the Roy Billinton Test System (RBTS) and the Chuanyu power system in Southwest China, are used to test the method proposed in this paper to verify its feasibility and accuracy.

Oncolytic viruses are being developed as novel strategies for cancer therapy. Our previous studies have shown that vaccinia viruses armed with marine lectins improved the antitumor efficacy in diverse cancer types. The objective of this study was to assess the cytotoxic effects of oncoVV harboring Tachypleus tridentatus lectin (oncoVV-TTL), Aphrocallistes vastus lectin (oncoVV-AVL), white-spotted charr lectin (oncoVV-WCL), and Asterina pectinifera lectin (oncoVV-APL) on HCC. Our data revealed that the effects of recombinant viruses on Hep-3B cells were oncoVV-AVL > oncoVV-APL > oncoVV-TTL > oncoVV-WCL; oncoVV-AVL showed stronger cytotoxicity than oncoVV-APL, while oncoVV-TTL/WCL had no effect on cell killing in Huh7 cells, and PLC/PRF/5 cells exhibited sensitivity to oncoVV-AVL/TTL but not to oncoVV-APL/WCL. The cytotoxicity of oncoVV-lectins could be enhanced by apoptosis and replication in a cell-type-dependent manner. Further research revealed that AVL may mediate various pathways, including MAPK, Hippo, PI3K, lipid metabolism, and androgen pathways through AMPK crosstalk, to promote oncoVV replication in HCC in a cell-dependent manner. OncoVV-APL replication could be affected by AMPK/Hippo/lipid metabolism pathways in Hep-3B cells, AMPK/Hippo/PI3K/androgen pathways in Huh7 cells, and AMPK/Hippo pathways in PLC/PRF/5 cells. OncoVV-WCL replication was also multi-mechanistic, which could be affected by AMPK/JNK/lipid metabolism pathways in Hep-3B cells, AMPK/Hippo/androgen pathways in Huh7 cells, and AMPK/JNK/Hippo pathways in PLC/PRF/5 cells. In addition, AMPK and lipid metabolism pathways may play critical roles in oncoVV-TTL replication in Hep-3B cells, and oncoVV-TTL replication in Huh7 cells may depend on AMPK/PI3K/androgen pathways. This study provides evidence for the application of oncolytic vaccinia viruses in hepatocellular carcinoma.

Our previous studies demonstrated that arming vaccinia viruses with marine lectins enhanced the antitumor efficacy in several cancer cells. This study aims to compare the efficacy of oncolytic vaccinia viruses harboring Tachypleus tridentatus lectin (oncoVV-TTL), Aphrocallistes vastus lectin (oncoVV-AVL), white-spotted charr lectin (oncoVV-WCL), and Asterina pectinifera lectin (oncoVV-APL) in breast cancer cells (BC). These results indicated that oncoVV-AVL elicited the highest anti-tumor effect, followed by oncoVV-APL, while oncoVV-TTL and oncoVV-WCL had lower effects in BC. Further studies showed that apoptosis and replication may work together to enhance the cytotoxicity of oncoVV-lectins in a cell-type dependent manner. TTL/AVL/APL/WCL may mediate multiple pathways, including ERK, JNK, Hippo, and PI3K pathways, to promote oncoVV replication in MDA-MB-231 cells. In contrast, these pathways did not affect oncoVV-TTL/AVL/APL/WCL replication in MCF-7 cells, suggesting that the mechanisms of recombinant viruses in MCF-7 (ER+, PR+) and MDA-MB-231 (TNBC) cells were significantly different. Based on this study, we hypothesized that ER or PR may be responsible for the differences in promoting viral replication and inducing apoptosis between MCF-7 and MDA-MB-231 cells, but the specific mechanism needs to be further explored. In addition, small-molecule drugs targeting key cellular signaling pathways, including MAPK, PI3K/Akt, and Hippo, could be conjunction with oncoVV-AVL to promote breast cancer therapy, and key pathway factors in the JNK and PI3K pathways may be related to the efficacy of oncoVV-APL/TTL/WCL. This study provides a basis for applying oncolytic vaccinia virus in breast carcinoma.

Classification of airborne laser scanning (ALS) point clouds of power lines is of great importance to their reconstruction. However, it is still a difficult task to efficiently and accurately classify the ground, vegetation, power lines and power pylons from ALS point clouds. Therefore, in this paper, a method is proposed to improve the accuracy and efficiency of the classification of point clouds of transmission lines, which is based on improved Random Forest and multi-scale features. The point clouds are filtered by the optimized progressive TIN densification filtering algorithm, then the elevations of the filtered point cloud are normalized. The features of the point cloud at different scales are calculated according to the basic features of the point cloud and the characteristics of transmission lines. The Relief F and Sequential Backward Selection algorithm are used to select the best subset of features to estimate the parameters of the learning model, then an Improved Random Forest classification model is built to classify the point clouds. The proposed method is verified by using three different samples from the study area and the results show that, compared with the methods based on Support Vector Machines, AdaBoost or Random Forest, our method can reduce feature redundancy and has higher classification accuracy and efficiency.

In order to improve the agility of college students, this paper designs a distributed agility training system. The system includes an upper computer and nine lower computers, in which the lower computer realizes the functions of data acquisition and communication with the upper computer and calculates the reaction time. The Android-based system software was installed in the upper computer to complete the functions of network connection, setting training times and showing the exercise time. In order to test the effectiveness of the equipment, nine university students were invited to complete agility training over 8 weeks with the help of agility training equipment in preparatory, enhancement and special stages. A t-test (Student’s t test) was conducted on the test results at different positions on the front and middle and back areas of the court before and after the training. The results show that the agility of the experimental objects was significantly improved after training, from the midpoint to any point at the front, middle and back court (p < 0.01). This shows that using equipment designed to develop agility for long-term training can promote the sensitive quality in badminton learners.

AIM: To develop a new material for retina filling and to investigate its effect on intraocular structure and histocompatibility in rabbit eyes. METHODS: The polymer-derived hyaluronic acid (HA) was formed by UV light cross-linked with N-vinyl-pyrrolidone. Vitrectomy was performed in the rabbits, and then cross-linked HA hydrogels at different concentrations were injected. Intraocular pressure measurements, cornea check-up, and B-ultrasound examination were performed during the follow-up period. After six weeks’ follow-up, the rabbits were sacrificed, and both eyes were removed for hematoxylin-eosin (HE) staining, and the polymer materials were observed under electron microscopy. RESULTS: The particle size of the cross-linked HA hydrogels was mainly around at 100 nm. After vitrectomy and injection into vitreous cavity optical coherence tomography showed that the polymeric material HA had no significant effect on the overall thickness of the retina. The intraocular pressure returned to the normal level gradually at week 4. B-ultrasound results revealed that there is no significant change in the eye tissue given to HA material. The pathological and transmission electron microscopy results showed no obvious pathological change in the primary cells and rod cells under the retina tissue. CONCLUSION: HA-based cross-linked biopolymers has good biocompatibility in rabbit eyes, showing a promising potential as vitreous substitutes.

Hepatic ischemia/reperfusion injury (HIRI) is a common complication of liver surgery requiring hepatic disconnection, such as hepatectomy and liver transplantation. The aim of this study was to investigate the effects of cordycepin on HIRI and to elucidate the underlying mechanisms. Balb/c mice were randomly divided into six groups: a normal control group, sham group, H-cordycepin group, HIRI group, L-cordycepin (25 mg/kg) + HIRI group, and H-cordycepin (50 mg/kg) + HIRI group. Mice were subjected to I/R, and cordycepin was intragastrically administered for seven consecutive days before surgery. Orbital blood and liver specimens were collected at 6 and 24 h after HIRI. Serum levels of ALT and AST were decreased in the cordycepin pretreatment groups. Notably, cordycepin attenuated the inflammatory response and the production of proapoptosis proteins, while increasing expression of antiapoptosis proteins and decreasing expression of autophagy-linked proteins. Furthermore, cordycepin inhibited activation of the MAPK/NF-κB signaling pathway. Collectively, these results indicate that cordycepin pretreatment ameliorated hepatocyte injury caused by HIRI. As compared with the HIRI group, cordycepin pretreatment mitigated the inflammatory response and inhibited apoptosis and autophagy via regulation of the MAPK/NF-κB signaling pathway.