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The optimization of the symmetry of MTDC systems after a contingency is crucial for the stable and economic operation of the MTDC systems. In this paper, a multi-objective optimal control method for the power flow symmetry of MTDC systems for the large-scale integration of offshore wind farms is proposed. A mirror relationship between the available headroom of DC lines and VSCs and their actual power flow distribution performance is established. A corresponding symmetry index is established for the MTDC network, and the multi-objective optimization problem is converted into a series of single-objective problems by the normal boundary intersection method, and solved by the original dyadic interior point method, so as to obtain the Pareto optimal solution with uniform distribution. The compromise optimal solution is decided according to the entropy weight double-basis point method, which provides decision-making guidance for the operators. The simulation results show that the normal boundary intersection method can solve the multi-objective dynamic optimal control problem of the VSC-HVDC system quickly and efficiently, and improve the symmetry of the power flow in an MTDC network. [ABSTRACT FROM AUTHOR]

Objective: To construct a machine learning diagnostic model integrating feature dimensionality reduction techniques and artificial neural network classifiers to develop the value of clinical routine blood indexes for the auxiliary diagnosis of ovarian cancer. Methods: Patients with ovarian cancer clearly diagnosed in our hospital were collected as a case group (n = 185), and three groups of patients with other malignant otolaryngology tumors (n = 138), patients with benign otolaryngology diseases (n = 339) and those with normal physical examination (n = 92) were used as an overall control group. In this paper, a fully automated segmentation network for magnetic resonance images of ovarian cancer is proposed to improve the reproducibility of tumor segmentation results while effectively reducing the burden on radiologists. A pre-trained Res Net50 is used to the three edge output modules are fused to obtain the final segmentation results. The segmentation results of the proposed network architecture are compared with the segmentation results of the U-net based network architecture and the effect of different loss functions and region of interest sizes on the segmentation performance of the proposed network is analyzed. Results: The average Dice similarity coefficient, average sensitivity, average specificity (specificity) and average hausdorff distance of the proposed network segmentation results reached 83.62%, 89.11%, 96.37% and 8.50, respectively, which were better than the U-net based segmentation method. For ROIs containing tumor tissue, the smaller the size, the better the segmentation effect. Several loss functions do not differ much. The area under the ROC curve of the machine learning diagnostic model reached 0.948, with a sensitivity of 91.9% and a specificity of 86.9%, and its diagnostic efficacy was significantly better than that of the traditional way of detecting CA125 alone. The model was able to accurately diagnose ovarian cancer of different disease stages and showed certain discriminative ability for ovarian cancer in all three control subgroups. Conclusion: Using machine learning to integrate multiple conventional test indicators can effectively improve the diagnostic efficacy of ovarian cancer, which provides a new idea for the intelligent auxiliary diagnosis of ovarian cancer. [ABSTRACT FROM AUTHOR]

Multi-gas tunable diode laser absorption spectroscopy (TDLAS) system based on time division multiplexing (TDM) demodulation technology which combine with frequency division multiplexing (FDM) technology is proposed, called F-TDM (frequency- time division multiplexing) system. In addition, traditional TDM technology and FDM technology are introduced to analyze and compare their performance. As for the performance of F-TDM system, multi-gas detection of CH4 and C2H2 has been accomplished with minimum detection limits of 10.24 ppmv for CH4 at 1653.72 nm and 0.763 ppmv for C2H2 at 1532.83 nm respectively. The relationships (CH4: R-square = 0.9989; C2H2: R-square = 0.9995) between gas concentration and second harmonic signal amplitude are proved as a good linear response. It is consistent with the data obtained by traditional TDM and FDM demodulation methods, indicating that the F-TDM system is feasible. By comparison, it is known that different methods have their advantages in different applications. The TDM system uses less equipment and is the most cost-effective. The system based on FDM technology is the most time-saving. The F-TDM system is a compromise method that combines the advantages of both and has no obvious disadvantage at the detection limit. [ABSTRACT FROM AUTHOR]

MicroRNAs (miRNAs) serve important roles in drug-resistance; however, exosomal miRNAs associated with drug-resistance in ovarian cancer (OC) have not been reported to date. The current study aimed to analyze the drug resistance-associated exosomal miRNAs in original OC cells and their derived exosomes using microarray data downloaded from the Gene Expression Omnibus database (series GSE76449). The chemosensitive OC cell lines SKOV3_ip1, A2780_PAR and HEYA8, as well as the chemoresistant cell lines SKOV3_TR, A2780_CP20 and HEYA8_MDR, were investigated. Differentially expressed miRNAs (DE-miRNAs) were identified using the limma method, and their mRNA targets were predicted using the miRWalk and LinkedOmics database. Functions of target genes were analyzed with DAVID tool, while TCGA data were used to explore the survival association of identified miRNAs. According to the results, 28 DE-miRNAs were found to be common in exosomal and original samples of A2780_CP20 cells, among which the functions of 5 miRNAs were predicted (including miR-146b-5p, miR-509-5p, miR-574-3p, miR-574-5p and miR-760). In addition, 16 and 35 DE-miRNAs were detected for HEYA8_MDR and SKOV3_TR, respectively, with the functions of 4 of these miRNAs predicted for each cell line (HEYA8_MDR: miR-30a-3p, miR-30a-5p, miR-612 and miR-617; SKOV3_TR: miR-193a-5p, miR-423-3p, miR-769-5p and miR-922). It was also reported that miR-183-5p was the only one common miRNA among the three cell lines. Furthermore, miR-574-3p, miR-30a-5p and miR-922 may regulate CUL2 to mediate HIF-1 cancer signaling pathway, while miR-183-5p may modulate MECP2, similar to miR-760, miR-30a-5p and miR-922, to influence cell proliferation. Finally, the downregulated miR-612 may promote the expression of TEAD3 via the Hippo signaling pathway, and this miRNA was associated with poor prognosis. In conclusion, the findings of the present study suggested several underlying miRNA targets for improving the chemotherapy sensitivity of OC. [ABSTRACT FROM AUTHOR]

The widely applied aromatic nitration in modern industry leads to toxic p -nitrophenol (PNP) in environment. Exploring its efficient degradation routes is of great interests. In this study, a novel four-step sequential modification procedure was developed to increase the specific surface area, functional group, hydrophilicity, and conductivity of carbon felt (CF). The implementation of the modified CF promoted reductive PNP biodegradation, attaining 95.2 ± 0.8% of removal efficiency with less accumulation of highly toxic organic intermediates (e.g., p -aminophenol), compared to carrier-free and CF-packed biosystems. The constructed anaerobic-aerobic process with modified CF in 219-d continuous operation achieved further removal of carbon and nitrogen containing intermediates and partial mineralization of PNP. The modified CF promoted the secretion of extracellular polymeric substances (EPS) and cytochrome c (Cyt c), which were essential components to facilitate direct interspecies electron transfer (DIET). Synergistic relationship was deduced that glucose was converted into volatile fatty acids by fermenters (e.g., Longilinea and Syntrophobacter), which donated electrons to the PNP degraders (e.g., Bacteroidetes_vadinHA17) through DIET channels (CF, Cyt c, EPS) to complete PNP removal. This study proposes a novel strategy using engineered conductive material to enhance the DIET process for efficient and sustainable PNP bioremediation. [Display omitted] • Four-step sequential modification for carbon felt (CF) was conducted. • Modified CF promoted PNP biodegradation, with less accumulation of PAP. • DIET was enhanced between fermenters and PNP degraders. • Contents of EPS and Cyt c facilitating DIET increased. [ABSTRACT FROM AUTHOR]

• An advanced methodology is developed for DC line power flow regulation without extra power flow controllers. • A pre-evaluation method is proposed to evaluate the power transfer and available control variables. • A novel control strategy is proposed to develop dispatch solutions for the MTDC system connected to AC girds and wind farms. The regulation of DC line power flow and optimization of system operational characteristics after contingency is crucial for the stable and economic operation of the MTDC grid. In this paper, a novel adaptive voltage reference based multi-objective optimal control method is proposed for proper line power flow control, as well as voltage deviation minimization and economic operation of the MTDC system. A hierarchical control method based on the M-MOMPA algorithm is proposed for the development of dispatch solutions for the MTDC system connected to multiple AC systems and large-scale wind farms. A pre-evaluation method is proposed to choose appropriate control variables and accelerate the convergence of optimization algorithms. The effectiveness of the proposed approach is validated through comparisons with several algorithms. The dynamic simulations of a five-terminal MTDC grid are carried out using MATLAB/Simulink and RTLAB to verify the effectiveness of the proposed method under various types of disturbance and contingency. [ABSTRACT FROM AUTHOR]

Conventional acoustic materials with uniform media which are of fixed impedance and density are unable to satisfy the requirements of the development of modern acoustic technology in volume, weight, pressure resistance and stealth performance. In this paper, composite structures with different gradient impedances are proposed. The influence of impedance gradient forms and discrete layering methods on acoustic performance is investigated numerically and experimentally. It is found that the gradient structure with exponential form improves absorbing performance in low frequency best among all these forms studied in terms of absorption coefficient and reflection coefficient. The curvature of the exponential curves shows the greatest effects on the position of the first absorption peak and the corresponding absorption coefficient. Better acoustic properties can be obtained in the case when adopting the equivalent layering method by thickness than that of the method equally layering by impedance. These findings provide useful guidance for application of underwater acoustic impedance gradient medium in engineering, especially for designing customized anechoic coating. Unlabelled Image • Composite structures with different gradient impedances are proposed. • The gradient structure with exponential form shows the best acoustic properties. • The impedance gradient forms and discrete layering methods show great effect on acoustic properties. [ABSTRACT FROM AUTHOR]

Interaction behaviors are a crucial, distinctive feature of organisms in ecological systems. Inspired by nature, micro‐/nanorobots also show interaction behaviors with a significant number of novel and advanced functionalities. The micro‐/nanoscale size and self‐driven abilities of micro‐/nanorobots have attracted considerable attention for potential applications. The mission of micro‐/nanorobots has evolved from basic mechanical transfer or assistance to a diverse range of complex tasks, such as targeted drug delivery, biosensing, and environmental remediation. Herein, we focus on the interaction behavior of coexisting cooperative cognitive (Tri‐Co) micro‐/nanorobots, summarize recent research, and classify the interactions into three broad types: with the environment, with robot peers, and with human external control. [ABSTRACT FROM AUTHOR]

Aims: CD47 is overexpressed in multiple tumours and plays an important role in immune escape and other biological processes of tumours. However, its role in adamantinomatous craniopharyngioma (ACP) remains unclear. Therefore, we explored the functions of CD47 in ACP. Methods: In this study, the expression of CD47 and the infiltration of immune cells in ACP was determined by immunohistochemistry (IHC) or immunofluorescence. Microglia‐mediated phagocytosis was analysed using an in vitro phagocytosis assay. Using lentivirus transfection, CD47 was either silenced or overexpressed in primary ACP cells and the biological effects of CD47 on these cells were evaluated in vitro using cell viability, flow cytometry, wound healing, Transwell migration and 3D hydrogel assays. The protein expression levels were analysed by western blotting. Results: Finger‐like protrusions, which may be the key factor in the recurrence of ACP, were primarily found in the region of hypothalamic involvement. The expression of CD47 was higher in palisading epithelium compared with stellate reticulum and epithelial whorls. An in vitro phagocytosis assay showed that CD47 blockade could promote microglia‐mediated phagocytosis. Functional assays revealed that CD47 promoted the growth, migration and invasion of ACP cells in vitro. Our mechanistic investigations showed that CD47 activated the MAPK/ERK pathway, thereby facilitating the biological behaviour of ACP cells. Conclusions: Here, we demonstrated that CD47 plays an important role in ACP cells, suggesting that CD47 could be a new potential therapeutic target for ACP, and adding to the body of literature a role for the inhibition of MAPK/ERK in ACP. [ABSTRACT FROM AUTHOR]

• A comprehensive dual-spectroscopy detection technique based on tunable diode laser absorption spectroscopy (TDLAS) and quartz enhanced photoacoustic spectroscopy (QEPAS) is demonstrated using a single quartz tuning fork (QTF) for signal detection. • A QTF was used as a photodetector and an acoustic wave transducer to detect the TDLAS and QEPAS signal simultaneously for 2f signal enhancement. • A gas absorption cell with 3 m optical path length was utilized to generate and enhance the TDALS signal. We tested the feasibility of the proposed dual-spectroscopy detection technique by detecting acetylene (C 2 H 2) at 1532.83 nm. • The signal of the dual-spectroscopy technique was approximately 1.13 and 8.71 times higher than that of the QEPAS and TDLAS techniques based on QTF. The proposed dual-spectroscopy detection technique also showed superior gas sensing capability for trace gas detection and could achieve a minimum detection limit of 1.05 ppm. A comprehensive dual-spectroscopy detection technique based on tunable diode laser absorption spectroscopy (TDLAS) and quartz enhanced photoacoustic spectroscopy (QEPAS) is demonstrated using a single quartz tuning fork (QTF) for signal detection. The QTF was utilized as an acoustic wave transducer for QEPAS signal detection. The QTF also served as a photoelectric detector for TDLAS signal detection based on the thermoelastic effect. The dual-spectroscopy detection structure was designed for TDLAS and QEPAS detection. The on-beam acoustic micro resonator (AMR) structure was placed on the upper end of the QTF for QEPAS signal enhancement, and the laser beam transmitted through the AMR was aligned to the QTF prong by an optical collimator for TDLAS signal detection. An absorption gas cell with an optical path length of 3 m was utilized in the TDLAS setup. The gas cell enhanced the absorption signal of the gas by virtue of its relatively long optical path. We tested the feasibility of the proposed dual-spectroscopy detection technique by detecting acetylene (C 2 H 2) at 1532.83 nm. The experimental show that the signal of the dual-spectroscopy detection technique is approximately 1.13 times that of the QEPAS signal. The proposed dual-spectroscopy detection technique also showed superior gas sensing capability for trace gas detection and could achieve a minimum detection limit of 1.05 ppm. The signal strength of the proposed dual-spectroscopy detection technique can be further enhanced by using an absorption gas cell with a longer optical path. [ABSTRACT FROM AUTHOR]

• A scanned-wavelength intra-cavity QEPAS sensor with injection seeding technique and Q-switched technique was reported. • The Q-switched fiber laser has a peak pulse power of 0.88 W. • A minimum detection limit (MDL) of 507 ppbv was achieved. A high sensitivity scanned-wavelength intra-cavity quartz enhanced photoacoustic spectroscopy (QEPAS) system, based on injection seeding technique and Q-switched technique, was proposed in this paper. In this system, the gas cell was placed in the acousto-optic Q-switched fiber laser cavity, and the high power Q-switched pulses were used to acoustic wave excitation. A distributed feedback (DFB) diode laser with a wavelength scanning range from 1532.63 nm to 1533.03 nm was used as the seed laser to select the laser wavelength. The laser power emitted by the seed laser operating at an injection current of 56 mA (the gas absorption peak) was 3 mW. A custom-made broadband fiber Bragg grating (FBG) with a bandwidth of 500 pm (picometer) was used to stabilize the cavity operation and suppress the amplified spontaneous emission (ASE) spectrum. With an intra-cavity peak pulse power of 0.88 W, the system achieved a minimum detection limit (MDL) of 507 ppbv at atmospheric pressure and room temperature, corresponding to a normalized noise-equivalent absorption (NNEA) of 1.616 × 10−8 W cm−1 Hz−1/2. [ABSTRACT FROM AUTHOR]