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278 results on '"Wang, Xuekun"'

14. Study on distribution of advance supporting stress and stability of coal pillar during the working face passing through abandon roadway

Author

WANG Xuekun

Subjects
abandon roadway, bearing stress, advanced coal pillar, theoretical calculation, numerical simulation, reinforcement, Mining engineering. Metallurgy, TN1-997
Abstract

The working face 1303 passing through the gob was studied by means of field investigation, laboratory test, theoretical analysis and numerical simulation, taking the engineering geological conditions of 1303 working face in the north wing of a mine in Datong, Shanxi Province as the background. The results show that the influence range of the leading bearing stress of the coal wall in the working face is 39.2 m, and that of the side bearing stress of the tunnel is 9.6 m. When the width of the coal pillar L is less than 48.8 m, the bearing stress begins to overlap; when the width of the coal pillar L is reduced from 50 m to 10 m, the peak stress keeps increasing continuously, and when the width of the coal pillar is 10 m, the peak stress is the largest, which is the critical bending stress width of coal pillar; when the width of coal pillar is less than 10 m, the critical yield state of coal pillar changes from full yield state to full yield state, and the peak stress shifts to the outer side of the goaf, so it is necessary to take additional measures to prevent the occurrence of coal rock dynamic disaster.

Published
2022
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15. Development of Xanthoangelol-Derived Compounds with Membrane-Disrupting Effects against Gram-Positive Bacteria.

Author

Yang, Siyu, Liu, Fangquan, Leng, Yue, Zhang, Meiyue, Zhang, Lei, Wang, Xuekun, and Wang, Yinhu

Subjects
BACTERIAL cell membranes, ANTIBACTERIAL agents, PLASMA stability, DRUG resistance in bacteria, ANTIMICROBIAL peptides
Abstract

Infections caused by multidrug-resistant pathogens have emerged as a serious threat to public health. To develop new antibacterial agents to combat such drug-resistant bacteria, a class of novel amphiphilic xanthoangelol-derived compounds were designed and synthesized by mimicking the structure and function of antimicrobial peptides (AMPs). Among them, compound 9h displayed excellent antimicrobial activity against the Gram-positive strains tested (MICs = 0.5–2 μg/mL), comparable to vancomycin, and with low hemolytic toxicity and good membrane selectivity. Additionally, compound 9h demonstrated rapid bactericidal effects, low resistance frequency, low cytotoxicity, and good plasma stability. Mechanistic studies further revealed that compound 9h had good membrane-targeting ability and was able to destroy the integrity of bacterial cell membranes, causing an increase in intracellular ROS and the leakage of DNA and proteins, thus accelerating bacterial death. These results make 9h a promising antimicrobial candidate to combat bacterial infection. [ABSTRACT FROM AUTHOR]

Published
2024
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20. Phosphine-Catalyzed γ′-Carbon 1,6-Conjugate Addition of α-Succinimide Substituted Allenoates with Para -Quinone Methides: Synthesis of 4-Diarylmethylated 3,4-Disubstituted Maleimides.

Author

Gao, Zhenzhen, Zhou, Xiaoming, Liu, Dandan, Nie, Baoshen, Lu, Hanchong, Chen, Xiaotong, Wu, Jiahui, Li, Lei, and Wang, Xuekun

Subjects
MALEIMIDES, BIOCHEMICAL substrates, CARBONYL compounds, QUINONE
Abstract

In this paper, an interesting γ′-carbon 1,6-conjugate addition for phosphine-catalyzed α-succinimide substituted allenoates has been disclosed. A wide array of substrates was found to participate in the reaction, resulting in the production of diverse 4-diarylmethylated 3,4-disubstituted maleimides with satisfactory to outstanding yields. Furthermore, a plausible mechanism for the reaction was proposed by the investigators. [ABSTRACT FROM AUTHOR]

Published
2024
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27. Discovery of a 4-Hydroxy-3′-Trifluoromethoxy-Substituted Resveratrol Derivative as an Anti-Aging Agent.

Author

Liang, Yinhu, Chen, Xi, Teng, Zhifeng, Wang, Xuekun, Yang, Jie, and Liu, Guoyun

Subjects
AGING prevention, RESVERATROL, CHOLINERGIC mechanisms, OXIDATIVE stress, PATHOLOGICAL physiology, AGING
Abstract

With the intensification of population aging, aging-related diseases are attracting more and more attention, thus, the study of aging mechanisms and anti-aging drugs is becoming increasingly urgent. Resveratrol is a potential candidate as an anti-aging agent, but its low bioavailability limits its application in vivo. In this work, a 4-hydroxy-3′-trifluoromethoxy-substituted resveratrol derivative (4–6), owing to its superior cell accumulation, could inhibit NO production in an inflammatory cell model, inhibit oxidative cytotoxicity, and reduce ROS accumulation and the population of apoptotic cells in an oxidative stress cell model. In D-galactose (D-gal)-stimulated aging mice, 4–6 could reverse liver and kidney damage; protect the serum, brain, and liver against oxidative stress; and increase the body's immunity in the spleen. Further D-gal-induced brain aging studies showed that 4–6 could improve the pathological changes in the hippocampus and the dysfunction of the cholinergic system. Moreover, protein expression related to aging, oxidative stress, and apoptosis in the brain tissue homogenate measured via Western blotting also showed that 4–6 could ameliorate brain aging by protecting against oxidative stress and reducing apoptosis. This work revealed that meta-trifluoromethoxy substituted 4–6 deserved to be further investigated as an effective anti-aging candidate drug. [ABSTRACT FROM AUTHOR]

Published
2024
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47. Machine vision on-line detecting system for effectively eliminating non-detection zone of surface defects

Author

Gao Shu-mei, Hong Cuncun, YU Wenwen, Cao Jianjun, Qian Wei-ying, and Wang Xuekun

Subjects
Light intensity, Planar, Materials science, Optics, Feature (computer vision), Plane (geometry), Image quality, Machine vision, business.industry, Planar array, Line (geometry), business, Atomic and Molecular Physics, and Optics
Abstract

For leather surface defects with the machine vision on-line detection, the image quality of some leather surface defects presented aeolotropism to the lighting direction, and the defects even failed to be shown, therefore the non-detection zone was formed. Considering this problem, an on-line detecting system which could eliminate the non-detection zone was designed. Based on the scattering and the information acquisition mechanism of the defect, the change law of the defect feature light intensity with the lighting direction was obtained. An experimental study on the defects of imprinting and ink was carried out to show that these two types of defect feature light intensity distributions were related to the lighting direction, and the non-detection zone as well as the effective zone of defects presented a orthogonal state. According to this, a self-designed off-axis plane light source with side-entering uniform irradiation was adapted to design the on-line detecting system for the orthogonal composition with linear array and planar array. The vertical target plane was used to collect the information and the dark field orthogonal lighting was carried out at 45°. The main detecting system was composed of the linear-array camera and the linear light source, while the auxiliary detecting system was composed of the planar camera and the off-axis plane light source to detect hundreds of samples of random anisotropic defects. The experimental results show that the defects non-detection zone is effectively eliminated, the defects recognition rate is increased by 22%, and the detection effciency is also greatly improved.

Published
2020

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