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1,078 results on '"Xu, Xudong"'

304. Semisynthesis and Biological Evaluation of Oleanolic Acid 3-O-β-d-Glucuronopyranoside Derivatives for Protecting H9c2 Cardiomyoblasts against H2O2-Induced Injury

Author

Tian, Yu, primary, Sun, Zhonghao, additional, Wang, Wenqian, additional, Shang, Hai, additional, Wang, Baoqi, additional, Deng, Di, additional, Ma, Guoxu, additional, Wu, Haifeng, additional, Zhu, Nailiang, additional, Xu, Xudong, additional, Sun, Guibo, additional, and Sun, Xiaobo, additional

Published
2018
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310. Figure error measurement method of cylindrical reflection mirror for conic approximate Wolter-I X-ray type telescope

Author

沈正祥 Shen Zhengxiang, 刘 娜 Liu Na, 王占山 Wang Zhanshan, 马 彬 Ma Bin, 魏振博 Wei Zhenbo, and 徐旭东 Xu Xudong

Subjects
Physics, Measurement method, business.industry, X-ray, Aerospace Engineering, Type (model theory), Atomic and Molecular Physics, and Optics, law.invention, Telescope, Reflection (mathematics), Optics, Space and Planetary Science, law, Conic section, Electrical and Electronic Engineering, business
Published
2018

329. FE Modeling of Tension Pin-end Connections

Author

Guan Fulin, Xu Xudong, and Tetsuro Ono

Subjects
Friction coefficient, Engineering, business.industry, Tension (physics), Numerical analysis, Connection (vector bundle), Building and Construction, Conservation, Radius, Structural engineering, Finite element method, Position (vector), Architecture, Connection type, business, Civil and Structural Engineering
Abstract

Pin-end connections have been widely used in tension structures. Accurate design methods are required to ensure these connections are safe and economic. The modeling of a given connection type is normally based on the determination of the connection behavior using experimental or numerical methods. This paper presents some finite-element (FE) modeling principles to analyze pin-end connections. The MSCMarc finite-element package is used to simulate the experimental behavior observed in tests conducted at the Nagoya Institute of Technology, Japan. The parameters varied in both the experiments and MSCMarc simulations are the inner radius of pin-block and gusset-block, the radius and the position of pin. The results obtained from the FE analyses are evaluated and the numerically predicted ultimate strengths are also compared with experiment data. It is shown that the proposed modeling principles are effective and efficient.

Published
2007

330. A Ca-alginate particle co-immobilized with Phanerochaete chrysosporium cells and the combined cross-linked enzyme aggregates from Trametes versicolor

Author

Xu Xudong, Liqiang Jin, Zhi Wang, and Yanchun Li

Subjects
Environmental Engineering, Alginates, Bioengineering, Phanerochaete, Microbiology, chemistry.chemical_compound, Trametes, Glucuronic Acid, Naphthalenesulfonates, Lignin, Coloring Agents, Waste Management and Disposal, Trametes versicolor, Chrysosporium, Laccase, biology, Renewable Energy, Sustainability and the Environment, Hexuronic Acids, General Medicine, biology.organism_classification, Glucuronic acid, chemistry, Peroxidases, biology.protein, Azo Compounds, Nuclear chemistry, Peroxidase
Abstract

For improving stability of immobilized white-rot fungus to treat various effluents, Phanerochaete chrysosporium cells and the combined cross-link enzyme aggregates (combi-CLEAs) prepared from Trametes versicolor were co-immobilized into the Ca-alginate gel particles in this paper. The activity yields of obtained combi-CLEAs were 42.7% for lignin peroxidases (LiPs), 31.4% for manganese peroxidases (MnPs) and 40.4% for laccase (Lac), respectively. And their specific activities were 30.2U/g as combi-CLEAs-LiPs, 9.5 U/g as combi-CLEAs-MnPs and 28.4 U/g as combi-CLEAs-Lac. Further, the present of the combi-CLEAs in the particles extremely improved their ability to degrade the dyes. Compared to the immobilized Ph. chrysosporium without the combi-CLEAs, the co-immobilized particles enhanced the decolorized rate of Acid Violet 7 (from 45.2% to 93.4%) and Basic Fuchsin (from 12.1% to 67.9%). In addition, the addition of the combi-CLEAs improved the adaptability of the white-rot fungal particles to adverse environmental conditions.

Published
2015

332. Eleucanainones A and B: Two Dimeric Structures from the Bulbs of Eleutherine americanawith Anti-MRSA Activity

Author

Chen, Deli, Sun, Zhaocui, Liu, Yangyang, Li, Zongyang, Liang, Hanqiao, Chen, Lei, Xu, Xudong, Yang, Junshan, Ma, Guoxu, and Huo, Xiaowei

Abstract

Two naphthoquinone-derived heterodimers with unprecedented carbon skeletons, eleucanainones A (1) and B (2), were isolated from the bulbs of Eleutherine americana. Their structures were elucidated by comprehensive spectroscopic methods. The structures of 1and 2were determined to be the first examples of dibenzofuran- and naphthalenone-containing naphthoquinone dimers. Compound 1exhibited significant anti-MRSA activity in vitro with minimum inhibitory concentration (MIC) values of 0.78 μg/mL by downregulation of basal expression of agrA, cidA, icaA and sarA in methicillin-resistant S. aureus(MRSA).

Published
2020
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333. A miniature insertion element transposable in Microcystis sp. FACHB 854*

Author

Kong Renqiu, Xu Xudong, and Xu Min

Subjects
Transposition (music), Transposable element, Genetics, Composite transposon, biology, Inverted repeat, Inverted Repeat Sequences, Microcystis, Direct repeat, General Materials Science, biology.organism_classification, Genome
Abstract

A 186-bp sequence with imperfect terminal inverted repeats and target direct repeats but without any transposase-encoding capacity was found to be transposable in an isolate derived from Microcystis sp. FACHB 854. This miniature insertion element, designated as ISM854-1, and with its homologues present at least 10 copies in the genome of Microcystis FACHB 854, is inserted into the 8-bp long and AT-rich target sequences, but none or few in other Microcystis strains. A variant of ISM854-1, denoted ISM854-1A, has perfect inverted repeat sequences and may transpose in pairs in a structure like a composite transposon. This is the first report of non-autonomous transposition of a mini-IS in a cyanobacterium.

Published
2006

334. Influence of colonic dialysis using Gubenxiezhuo on the distribution of gut microflora in uremia rats.

Author

He, Haidong, Hu, Ping, Tang, Yuyan, and Xu, Xudong

Subjects
BACILLUS cereus, UREMIA, RATS
Abstract

Objective: This study aimed to explore the underlying function of Gubenxiezhuo dialysis on the distribution of gut microflora uremia. Methods: A uremia rat model was constructed, and the morphology of renal tissue was determined using the hematoxylin‐eosin (H&E) staining. Moreover, the blood samples were collected and the expression of IL‐1β, IL‐6, and CRP was determined using enzyme‐linked immunosorbent assay. Following these experiments, the gut tissues of rats were collected and the distribution of gut microbiota was explored using real‐time PCR. Results: Compared with the control group, inflammatory infiltration, apoptosis, and bleeding were significantly upregulated in kidney of uremia rats, and Gubenxiezhuo dialysis could obviously ameliorate these changes. Expression of IL‐1β, IL‐6, and CRP were significantly elevated in uremic rats and Gubenxiezhuo could significantly attenuate these elevations (p < 0.01). In addition, Gubenxiezhuo dialysis also could attenuate the upregulations of Acinetobacter, Bacillus cereus, Proteus vulgaris, Shigella flexneri, and Escherichia coli , and the downregulation of Bifidobacterium, Lactobacillus, and Helicobacter in the uremia rats (p < 0.05). Conclusion: Gubenxiezhuo dialysis could significantly ameliorate the inflammatory to modulate the distribution of gut microbiota in uremia. Gubenxiezhuo dialysis could significantly ameliorate the inflammatory to modulate the distribution of gut microbiota in uremia. [ABSTRACT FROM AUTHOR]

Published
2019
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335. Mechanism of Regulation of Big-Conductance Ca2+-Activated K+ Channels by mTOR Complex 2 in Podocytes.

Author

Wang, Yinhang, Tao, Jie, Wang, Mengling, Yang, Licai, Ning, Fengling, Xin, Hong, Xu, Xudong, Cai, Hui, Zhang, Weiguang, Yu, Ker, and Zhang, Xuemei

Subjects
MECHANICAL movements, RAPAMYCIN, PROTEIN expression, MESSENGER RNA, CYTOSKELETON
Abstract

Podocytes, dynamic polarized cells wrapped around glomerular capillaries, are an essential component of the glomerular filtration barrier. BK channels consist of one of the slit diaphragm (SD) proteins in podocytes, interact with the actin cytoskeleton, and play vital roles in glomerular filtration. Mechanistic target of rapamycin (mTOR) complexes regulate expression of SD proteins, as well as cytoskeleton structure, in podocytes. However, whether mTOR complexes regulate podocyte BK channels is still unclear. Here, we investigated the mechanism of mTOR complex regulation of BK channels via real-time PCR, western blot, immunofluorescence, and patch clamping. Inhibiting mTORC1 with rapamycin or downregulating Raptor had no significant effect on BK channel mRNA and protein levels and bioactivity. However, the dual inhibitor of mTORC1 and mTORC2 AZD8055 and short hairpin RNA targeting Rictor downregulated BK channel mRNA and protein levels and bioactivity. In addition, MK2206, GF109203X, and GSK650394, which are inhibitors of Akt, PKCα, and SGK1, respectively, were employed to test the downstream signaling pathway of mTORC2. MK2206 and GF109203X had no effect on BK channel protein levels. MK2206 caused an obvious decrease in the current density of the BK channels. Moreover, GSK650394 downregulated the BK channel protein and mRNA levels. These results indicate mTORC2 not only regulates the distribution of BK channels through Akt, but also modulates BK channel protein expression via SGK1 in podocytes. [ABSTRACT FROM AUTHOR]

Published
2019
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336. Congmujingnosides B-G, triterpene saponins from the stem of Aralia chinensis and their protective effects against H2O2-induced myocardial cell injury.

Author

Zhang, Wen, Zhu, Nailiang, Hu, Meigeng, Yu, Shichun, Sun, Zhonghao, Wu, Haifeng, Li, Pengfei, Yang, Junshan, Ma, Guoxu, and Xu, Xudong

Abstract

Phytochemical investigation of the stem of Aralia chinensis yielded six new oleanane-type triterpene saponins named as congmujingnosides B-G (1–6). The new ones were elucidated on the basis of the chemical and spectroscopic analysis. Protective effects of compounds 1−6 were tested against H2O2-induced H9c2 cardiomyocyte injury, and the data showed that compounds 1 and 5 had significant cell-protective effects. No significant DPPH radical scavenging activity was observed for compounds 1−6. [ABSTRACT FROM AUTHOR]

Published
2019
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338. Attaining the Utmost Stability and Energy of Carbonyl Azides by the Synergistic Improvement of Conjugation and H-bonding

Author

Tian, Baojing, Ding, Ning, Xu, Xudong, Jiang, Zhiyi, Chang, Jinyu, Jiang, Yanda, Zhao, Chaofeng, Sun, Qi, Li, Shenghua, and Pang, Siping

Abstract

Carbonyl azides are important precursors to isocyanates and are used as energetic compounds. However, the further development of these compounds is limited by their inherently poor stability. In this study, we present a new family of carbonyl azides, 5-nitro-1H-1,2,4-triazol-3-yl-carbamoyl-azide (NTCA), which was synthesized through in situ oxidation cleavage of amino-tetrazole. Compared with its precursor (nitrocarbamoyl azide, HNCA), X-ray data and quantum calculations indicate that NTCA has much stronger conjugation (dihedral angle decreased from 13.39° to 1.35°) and more H-bonds (increase from 2 to 7 pairs). As a result, NTCA exhibits the highest thermal stability (decomposition temperature of 212 °C) and highest density (1.820 g cm−3) among all known carbonyl azides. In addition, a series of Curtius rearrangements were performed to generate substituted ionic derivatives, which also exhibit high stability and energy. This study provides an effective strategy for synthesizing carbonyl azides with high stability and energy, paving the way for future practical applications.

Published
2024
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339. 1-Trinitromethyl-3,5-dinitro-4-nitroaminopyrazole: Intramolecular Full Nitration and Strong Intermolecular H-Bonds toward Highly Dense Energetic Materials

Author

Ding, Ning, Sun, Qi, Xu, Xudong, Zhang, Wenjin, Zhao, Chaofeng, Li, Shenghua, and Pang, Siping

Abstract

Full nitration is one of the most effective strategies used in synthesizing high-density energetic materials, but this strategy has reached its limit because the resultant compounds cannot be further functionalized. To overcome this limitation, we present the synergistic action of full nitration and strong intermolecular H-bonding in designing and synthesizing 1-trinitromethyl-3,5-dinitro-4-nitroaminopyrazole (DNTP) with a density that exceeds those of the reported monocyclic CHON compounds. The detonation velocity and specific impulse of DNTP exceed those of 1-trinitromethyl-3,4,5-trinitropyrazole (TTP), HMX, and ADN.

Published
2024
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340. Discovery of Cadinane-Type Sesquiterpenoids from the Infected Stems of Hibiscus tiliaceusas Potential Agrochemical Fungicides

Author

Chen, Deli, Xu, Xudong, Yang, Yun, Meng, Hui, Xu, Minghui, Dong, Lin, Ma, Guoxu, and Zhang, Xiaopo

Abstract

Ten new cadinane-type sesquiterpenoids, named hibisceusins I–R (1–10), along with 14 known sesquiterpenoids (11–24), were acquired from the tainted stems of Hibiscus tiliaceus. Their structures were identified via spectroscopic analysis, one-dimensional (1D) and two-dimensional (2D) NMR, and computer-assisted structure elucidation techniques, including infrared (IR) and mass spectrometry (MS) data. Additionally, subsequent DP4/DP4+ probability methods were used to resolve 3′s relative configurations by comparing their experimental values to the predicted NMR data. The absolute configurations of compounds 1–4were measured through electronic circular dichroism (ECD) spectra. The ability of all isolates to inhibit the growth of five phytopathogenic fungi (Rhizopus stolonifer, Verticillium dahliaeKleb., Thanatephorus cucumeris, Fusarium oxysporumSchltdl., and F. oxysporumHK-27) was evaluated. Aldehydated sesquiterpenoids (1, 6–9, 11, 12, and 22) and a known sesquiterpenoid quinine (18) exhibited significant inhibitory activities against V. dahliae, T. cucumeris, F. oxysporum, and F. oxysporumHK-27 with minimum inhibitory concentration (MIC) values of 2.5–50 μg/mL, but all isolates remained inactive against R. stolonifer. Moreover, the effects of the isolates on the mycelial morphology were watched through scanning electron microscopy. This study revealed that aldehydated cadinane-type sesquiterpenoids could be used as novel antifungal molecules to develop agrochemical fungicides in plant protection.

Published
2024
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342. Multiple microdischarge dynamics in dielectric barrier discharges

Author

Xu, Xudong, Peter and Kushner, Mark J.

Subjects
Dielectric devices -- Observations, Electric discharges -- Observations, Physics
Abstract

Dielectric barrier discharges (DBDs) are pulsed atmospheric pressure devices where plasma forms as microdischarge array. Microdischarges may interact during their expansion if spaced sufficiently close together. A two-dimensional plasma hydrodynamics model is proposed for microdischarge development in DBDs. The aim was to study the interaction between closely spaced microdischarges. Ionization efficiency was only moderately affected by microdischarges expanding into physical contact.

Published
1998

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