Blind Image Quality Assessment Based on Multi-Window Method and HSV Color Space

To improve the evaluation accuracy of the distorted images with various distortion types, an effective blind image quality assessment (BIQA) algorithm based on the multi-window method and the HSV color space is proposed in this paper. We generate multiple normalized feature maps (NFMs) by using the multi-window method to better characterize image degradation from the receptive fields of different sizes. Specifically, the distribution statistics are first extracted from the multiple NFMs. Then, Pearson linear correlation coefficients between spatially adjacent pixels in the NFMs are utilized to quantify the structural changes of the distorted images. Weibull model is utilized to capture distribution statistics of the differential feature maps between the NFMs to more precisely describe the presence of the distortions. Moreover, the entropy and gradient statistics extracted from the HSV color space are employed as a complement to the gray-scale features. Finally, a support vector regressor is adopted to map the perceptual feature vector to image quality score. Experimental results on five benchmark databases demonstrate that the proposed algorithm achieves higher prediction accuracy and robustness against diverse synthetically and authentically distorted images than the state-of-the-art algorithms while maintaining low computational cost

Modified Modeling and System Stabilization of Shunt Active Power Filter Compensating Loads with μF Capacitance

The interactions between shunt active power filter (APF) and capacitance load tend to result in stability problems and resonance. The conventional model of a shunt APF is not precise enough to reflect this phenomenon. To address it, this paper proposes a modified shunt APF system model to accurately reflect various stability problems. This paper also studies the mechanism of positive feedback resonance brought by capacitance load and proposes a modified hybrid controller to improve the stable margin of the system, making the shunt APF work stably under different working conditions where there are μF capacitors on the demand side. The correctness and validity of the proposed strategy are verified by simulation analysis and prototype experiments

Sequence-admittance-based stability analysis for multiple parallel converters

With the development of energy storage system, the voltage-controlled converters (VCCs) that can achieve voltage and frequency support have become hot spots in both theory and practice. Therefore, apart from the traditional multiple parallel current-controlled converters (CCCs), multiple parallel VCCs and multiple parallel hybrid-controlled converters (HCCs) consisting of both the CCCs and VCCs have emerged, which makes stability issues of multi-converter grid-connected systems more complex. To cope with stability concerns related to different kinds of multiple parallel converter systems, this paper analyzes the interactive process of circuit-coupling and frequency-coupling among grid-connected converters and develops equivalent sequence-admittance-based stability analysis models. Based on the proposed models, stability recognition of grid-connected CCCs, VCCs and HCCs are derived. Finally, the effectiveness of the built models and the correctness of the stability analysis results are verified by experiments

Sintering study of ITO using a ZnO-doped and microwave hybrid sintering approach

ITO ceramics with full densities are difficult to achieve using conventional heating because of the volatilization property of both indium oxide (In2O3) and tin oxide (SnO2) at high temperatures. In our present study, we proposed to use a ZnO-doped and microwave hybrid-sintering approach to prepare for ITO ceramics with full densities under normal atmospheric condition. The investigation on the effect of the content of ZnO on the densification and resistivity of the ITO ceramics showed that as the ZnO content increased, the relative density of the ceramics increased while the weight loss and grain size decreased. The resistivity of the ceramics initially decreased by increasing the ZnO content but increased when the content of ZnO was more than 9.09 wt.%. Employing this logic, a relative density approaching 99% of the theoretical density was obtained and the sintering time required was just 25 min. The obtained ITO ceramics were pure ITO phase and had the lowest resistivity and the relative density of 98.1% when the content of ZnO was 9.09 wt.%. This hybrid sintering approach might open a new avenue in the fabrication of ITO ceramics with high densities

Pterostilbene Inhibits the Growth of Human Esophageal Cancer Cells by Regulating Endoplasmic Reticulum Stress

Background/Aims: Pterostilbene (PTE), a natural dimethylated resveratrol analog from blueberries, is known to have diverse pharmacological activities, including anticancer properties. In this study, we investigated the anticancer activity of PTE against human esophageal cancer cells both in vitro and in vivo and explored the role of endoplasmic reticulum (ER) stress (ERS) signaling in this process. Methods: Cell viability, the apoptotic index, Caspase 3 activity, adhesion, migration, reactive oxygen species (ROS) levels, and glutathione (GSH) levels were detected to explore the effect of PTE on human EC109 esophageal cancer cells. Furthermore, siRNA transfection and a chemical inhibitor were employed to confirm the role of ERS. Results: PTE treatment dose- and time-dependently decreased the viability of human esophageal cancer EC109 cells. PTE also decreased tumor cell adhesion, migration and intracellular GSH levels while increasing the apoptotic index, Caspase 3 activity and ROS levels, which suggest the strong anticancer activity of PTE. Furthermore, PTE treatment increased the expression of ERS-related molecules (GRP78, ATF6, p-PERK, p-eIF2α and CHOP), upregulated the pro-apoptosis-related protein PUMA and downregulated the anti-apoptosis-related protein Bcl-2 while promoting the translocation of cytochrome c from mitochondria to cytosol and the activation of Caspase 9 and Caspase 12. The downregulation of ERS signaling by CHOP siRNA desensitized esophageal cancer cells to PTE treatment, whereas upregulation of ERS signaling by thapsigargin (THA) had the opposite effect. N-Acetylcysteine (NAC), a ROS scavenger, also desensitized esophageal cancer cells to PTE treatment. Conclusions: Overall, the results indicate that PTE is a potent anti-cancer pharmaceutical against human esophageal cancer, and the possible mechanism involves the activation of ERS signaling pathways

Peptide-Conjugated Fluorescent Silicon Nanoparticles Enabling Simultaneous Tracking and Specific Destruction of Cancer Cells

We herein introduce a kind of fluorescent silicon nanoparticles (SiNPs) bioprobes, that is, peptides-conjugated SiNPs, which simultaneously feature small sizes (<10 nm), biological functionality, and stable and strong fluorescence (photoluminescent quantum yield (PLQY): ∼28%), as well as favorable biocompatibility. Taking advantage of these merits, we further demonstrate such resultant SiNPs bioprobes are superbly suitable for real-time immunofluorescence imaging of cancer cells. Meanwhile, malignant tumor cells could be specifically destroyed by the peptides-conjugated SiNPs, suggesting potential promise of simultaneous detection and treatment of cancer cells

In Vitro Investigation of Enhanced Hemocompatibility and Endothelial Cell Proliferation Associated with Quinone-Rich Polydopamine Coating

Recent investigations have demonstrated that polydopamine (PDA)-modified surfaces were beneficial to the proliferation of endothelial cells (ECs). In this work, PDA coated 316L stainless steels (316L SS) were thermally treated at 50, 100, and 150 °C respectively (hereafter designated as Th50, Th100, and Th150) and consequently produced diverse surface chemical components. In vitro hemocompatibility and vascular cell-material interactions with ECs and smooth muscle cells (SMCs) affected by surface characteristics have been investigated. The Th150, rich in quinone, showed the best hemocompatibility and could effectively inhibit platelet adhesion, activation, and fibrinogen conformation transition. The polydopamine-modified surfaces were found to induce dramatic cell-material interaction with enhanced ECs proliferation, viability and migration, release of nitric oxide (NO), and reduced SMCs proliferation. The inhibitory effect of SMCs proliferation might be associated with the surface catechol content. The coating on Th150 showed a good resistance to the deformation of compression and expansion of vascular stents. These results effectively suggested that the Th150 coating might be promising when served as a stent coating platform