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Your search keyword '"Zhu, Zhi-Xiang"' showing total 135 results
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135 results on '"Zhu, Zhi-Xiang"'

15. Two new diterpenoids from Penicillium chrysogenum MT-12, an endophytic fungus isolated from Huperzia serrata.

Author

Qi, Bowen, Jia, Fangfang, Luo, Yuan, Ding, Ning, Li, Sainan, Shi, Fanyu, Hai, Yan, Wang, Lili, Zhu, Zhi-Xiang, Liu, Xiao, Tu, Pengfei, and Shi, She-Po

Subjects
PENICILLIUM chrysogenum, ENDOPHYTIC fungi, DITERPENES, CIRCULAR dichroism, MEDICINAL plants
Abstract

Two new diterpenoids, penicichrysogene A (1) and penicichrysogene B (2), were isolated from the solid substrate fermentation cultures of Penicillium chrysogenum MT-12, an endophytic fungus isolated from the medicinal plant of Huperzia serrata. Their structures were elucidated on the basis of extensive spectroscopic and spectrometric data (1D and 2D NMR, UV, IR, and HRESIMS). The absolute configurations of 1 and 2 were assigned on the basis of experimental and calculated electronic circular dichroism spectra. Compound 1 exhibited inhibitory activity on ATP release of thrombin-activated platelets with IC50 = 42.7 ± 3.5 μM. [ABSTRACT FROM AUTHOR]

Published
2022
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24. Research and Application of Image Retrieval Improved Algorithm Based on BOF

Author

Lu Hai Hong and Zhu Zhi Xiang

Subjects
Dimensionality reduction, InformationSystems_INFORMATIONSTORAGEANDRETRIEVAL, Inverted index, computer.software_genre, Image (mathematics), Dimension (vector space), Feature (computer vision), Signal Processing, Content (measure theory), Point (geometry), Data mining, Image retrieval, computer, Mathematics
Abstract

The feature description of image and the index mechanism of the feature are the keys to realize the content-based image retrieval, aiming at the problem of massive image data and “dimension curse”, this paper proposes the BOF-based image retrieval improved algorithm, and combines with VLAD and soft assignment it generates the soft assignment local aggregation descriptor (SA-VLAD) which has a better ability to resist the dimension reduction and a higher recognition rate. When the index mechanism IVFADC is at query time, to ensure the recall ratio and precision rate of the result, the candidates inverted index chain are increased, which leads to the problems of distance calculation and the query time’s increasing. For this point, in the index phase, the scattered distribution is carried out aiming at the database vector, which reduces the burden of distance calculation, and improves the quality of the query results at the same time. The experimental results show that the algorithm in this paper obtains a good effect in the content-based massive image database retrieval.

Published
2015

25. Across-cohort QC analyses of GWAS summary statistics from complex traits

Author

Trzaskowski, Maciej, Yang, Jian, Robinson, Matthew R, Lee, Sang Hong, Visscher, Peter M., Chen, Guo-Bo, Loos, Ruth J F, Zhu, Zhi-Xiang, Wray, Naomi R, Locke, Adam E, Winkler, Thomas W, Frayling, Timothy M, Hirschhorn, Joel N, Day, Felix R, Croteau-Chonka, Damien C, Wood, Andrew R, and Kutalik, Zoltán

Abstract

Genome-wide association studies (GWASs) have been successful in discovering SNP trait associations for many quantitative traits and common diseases. Typically, the effect sizes of SNP alleles are very small and this requires large genome-wide association meta-analyses (GWAMAs) to maximize statistical power. A trend towards ever-larger GWAMA is likely to continue, yet dealing with summary statistics from hundreds of cohorts increases logistical and quality control problems, including unknown sample overlap, and these can lead to both false positive and false negative findings. In this study, we propose four metrics and visualization tools for GWAMA, using summary statistics from cohort-level GWASs. We propose methods to examine the concordance between demographic information, and summary statistics and methods to investigate sample overlap. (I) We use the population genetics Fst statistic to verify the genetic origin of each cohort and their geographic location, and demonstrate using GWAMA data from the GIANT Consortium that geographic locations of cohorts can be recovered and outlier cohorts can be detected. (II) We conduct principal component analysis based on reported allele frequencies, and are able to recover the ancestral information for each cohort. (III) We propose a new statistic that uses the reported allelic effect sizes and their standard errors to identify significant sample overlap or heterogeneity between pairs of cohorts. (IV) To quantify unknown sample overlap across all pairs of cohorts, we propose a method that uses randomly generated genetic predictors that does not require the sharing of individual-level genotype data and does not breach individual privacy.

Published
2017
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26. CVD Synthesis of Monodisperse Graphene/Cu Microparticles with High Corrosion Resistance in Cu Etchant

Author

Li, Shuangyi, primary, Hou, Baosen, additional, Dai, Dan, additional, Shu, Shengcheng, additional, Wu, Mingliang, additional, Li, Ao, additional, Han, Yu, additional, Zhu, Zhi-xiang, additional, Chen, Bao-an, additional, Ding, Yi, additional, Zhang, Qiang, additional, Wang, Qiang, additional, Jiang, Nan, additional, and Lin, Cheng-Te, additional

Published
2018
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27. Megastigmane glycosides from Urena lobata

Author

Su, Cong, primary, Qi, Bowen, additional, Wang, Juan, additional, Ding, Ning, additional, Wu, Yun, additional, Shi, Xiao-Ping, additional, Zhu, Zhi-Xiang, additional, Liu, Xiao, additional, Wang, Xiao-Hui, additional, Zheng, Jiao, additional, Tu, Peng-Fei, additional, and Shi, She-Po, additional

Published
2018
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31. Across-cohort QC analyses of GWAS summary statistics from complex traits

Author

Chen, Guo-Bo, Lee, Sang Hong, Robinson, Matthew R, Trzaskowski, Maciej, Zhu, Zhi-Xiang, Winkler, Thomas W, Day, Felix R, Croteau-Chonka, Damien C, Wood, Andrew R, Locke, Adam E, Kutalik, Zoltán, Loos, Ruth JF, Frayling, Timothy M, Hirschhorn, Joel N, Yang, Jian, Wray, Naomi R, Genetic Investigation Of Anthropometric Traits (GIANT) Consortium, Visscher, Peter M, Chen, Guo-Bo [0000-0001-5475-8237], Day, Felix R [0000-0003-3789-7651], Yang, Jian [0000-0003-2001-2474], Wray, Naomi R [0000-0001-7421-3357], Visscher, Peter M [0000-0002-2143-8760], and Apollo - University of Cambridge Repository

Subjects
Cohort Studies, Genetic Heterogeneity, Phenotype, Genotype, Meta-Analysis as Topic, Quantitative Trait Loci, Humans, Polymorphism, Single Nucleotide, Alleles, Software, Genome-Wide Association Study
Abstract

Genome-wide association studies (GWASs) have been successful in discovering SNP trait associations for many quantitative traits and common diseases. Typically, the effect sizes of SNP alleles are very small and this requires large genome-wide association meta-analyses (GWAMAs) to maximize statistical power. A trend towards ever-larger GWAMA is likely to continue, yet dealing with summary statistics from hundreds of cohorts increases logistical and quality control problems, including unknown sample overlap, and these can lead to both false positive and false negative findings. In this study, we propose four metrics and visualization tools for GWAMA, using summary statistics from cohort-level GWASs. We propose methods to examine the concordance between demographic information, and summary statistics and methods to investigate sample overlap. (I) We use the population genetics Fst statistic to verify the genetic origin of each cohort and their geographic location, and demonstrate using GWAMA data from the GIANT Consortium that geographic locations of cohorts can be recovered and outlier cohorts can be detected. (II) We conduct principal component analysis based on reported allele frequencies, and are able to recover the ancestral information for each cohort. (III) We propose a new statistic that uses the reported allelic effect sizes and their standard errors to identify significant sample overlap or heterogeneity between pairs of cohorts. (IV) To quantify unknown sample overlap across all pairs of cohorts, we propose a method that uses randomly generated genetic predictors that does not require the sharing of individual-level genotype data and does not breach individual privacy.

Published
2016

32. Dimeric furanocoumarins from the roots of Angelica dahurica

Author

Yang, Wan-Qing, Zhu, Zhi-Xiang, Song, Yue-Lin, Qi, Bo-Wen, Wang, Juan, Su, Cong, Tu, Peng-Fei, and She-Po Shi

Abstract

Three new dimeric furanocoumarins, dahuribiethrins H–J (1–3), and a new ester coumarin, dahurinol A (4), were isolated from the roots of Angelica dahurica. Their structures were elucidated on the basis of extensive spectroscopic data including UV, IR, HRESIMS, 1D and 2D NMR. Compounds 2 and 3 exhibited inhibition of nitric oxide production in the lipopolysaccharide (LPS)-stimulated RAW 264.7 macrophage cells with IC50 values of 8.7 ± 0.6 and 27.3 ± 0.9 μM, respectively.

Published
2016
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39. Chemical constituents from the roots and stems of Litsea cubeba

Author

Guo, Qiang, Bai, Rui-Feng, Su, Guo-Zhu, Zhu, Zhi-Xiang, Zeng, Ke-Wu, Tu, Peng-Fei, and Xing-Yun Chai

Abstract

A new monoterpene and a new lignan, named litsecols A and B (1 and 2), respectively, together with nine known compounds (3–11), were isolated in a continuous investigation on the roots and stems of Litsea cubeba. Their structures were elucidated on the basis of extensive spectroscopic data analysis, and the absolute configuration of 1 was resolved by X-ray diffraction analysis. Compounds 2–5 and 7–9 showed significant inhibitory activity against nitric oxide (NO) production in lipopolysaccharide (LPS)-induced murine microglial (Bv-2) cell line. Compounds 10 and 11 exhibited significant neuroprotective effect against hydrogen peroxide-induced oxidative damage in rat adrenal pheochromocytoma (PC12) cell line.

Published
2015
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40. Two new polyketides from the fungus Penicillium oxalicum MHZ153.

Author

Ren, Yi, Chao, Ling-Hui, Sun, Jing, Chen, Xiao-Nan, Yao, Hui-Na, Zhu, Zhi-Xiang, Dong, Dan, Liu, Ting, Tu, Peng-Fei, and Li, Jun

Abstract

Two new polyketides, penicilloxalones A (1) and B (2), together with 13 known compounds (3–15), were isolated from the ethyl acetate extract of the solid substrate fermentation cultures of the fungus Penicillium oxalicum MHZ153. The structures of the isolates were determined by spectroscopic analysis and comparison of their spectroscopic and physicochemical data with the literature values. Compounds 7 and 11 showed inhibition of nitric oxide production in lipopolysaccharide-stimulated BV-2 microglial cells with IC50 values of 0.9 ± 0.2 μM and 87.9 ± 0.7 μM, respectively. [ABSTRACT FROM AUTHOR]

Published
2019
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49. Effect of Stoichiometry and Temperature on NOxReduction by Reagent Injection in the Fuel-Rich Zone of Pulverized Coal Combustion

Author

Bi, De gui, Zhang, Zhong xiao, Dong, Jian cong, Zhu, Zhi xiang, and Yu, Juan

Abstract

In this paper, the characteristics of NOxreduction by reagent injection into the fuel-rich zone (RIFR) in coal combustion were investigated, under high temperatures and reducing atmosphere conditions. The stoichiometry and temperature have a major influence on the chemistry of NO and NH3reagent (ammonia or urea). Therefore, experiments were conducted on a bench-scale test system with urea solution as the reagent to investigate the key factors influencing NOxreduction, including primary stoichiometric ratio (SR1), temperature in the reaction zone, and normalized stoichiometric ratio (NSR) of the injected reagent. The results indicated that the primary stoichiometric ratio SR1was the key parameter affecting the reduction of NOxemissions. Better NOxreduction was achieved with a decrease in the SR1for bare air staging. However, there was no benefit for NOxreduction by reagent injection in the very fuel-rich zone (SR1≤ 0.75), which depended on the distribution of N-intermediates and initial NO concentration. On the other hand, a negative NOxreduction was obtained by reagent injection when SR1≥ 0.95 because the added reagent was oxidized to form NO. The optimum SR1for RIFR was found to be 0.85 in this study. A higher SR1greatly improved the NOxreduction by RIFR only when SR1was less than 1, and high temperatures (1473–1673 K) were required for the generation of more OH free-radicals in the fuel-rich zone, which promoted NOxreduction by NH3in the absence of oxygen. Therefore, RIFR is different from the traditional selective non-catalytic reduction technology, which has a strong temperature dependency from 1100–1300 K. The NOxreduction efficiency was increased by 21.4% with RIFR compared to the bare air-staged method, under the optimum conditions of SR1= 0.85, T= 1673 K, and NSR = 2. More urea solution led to greater NOxformation in the burnout zone but with no ammonia slip. This method can be applied as a new alternative technology to further reduce NOxin combination with the existing low NOxcombustion technologies.

Published
2019
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