32 results on '"Yun-Fang, Li"'
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2. Forest characteristics, population structure and growth trends of Pinus yunnanensis in Tianchi National Nature Reserve of Yunnan, southwestern China
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Cindy Q. Tang, Li-Qin Shen, Peng-Bin Han, Diao-Shun Huang, Shuaifeng Li, Yun-Fang Li, Kun Song, Zhi-Ying Zhang, Long-Yun Yin, Rui-He Yin, and Hui-Ming Xu
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Environmental sciences ,GE1-350 - Abstract
Aims: Pinus yunnanesis is commercially, culturally and economically important, but there is a lack of ecological data on its role in stand dynamics. Our aims are to clarify the structure, composition, regeneration and growth trends of primary mature P. yunnanensis forests. Study area: The Tianchi National Nature Reserve in the Xuepan Mountains, Yunlong County, northwestern Yunnan, China. Methods: We investigated forests containing P. yunnanensis, measured tree ages and analyzed the data. Results: Six forest types were identified: (1) coniferous forest: Pinus yunnanensis (Type 1); (2) mixed coniferous and evergreen broad-leaved forest: P. yunnanensis-Lithocarpus variolosus (Type 2); (3) mixed coniferous and deciduous broad-leaved forest: P. yunnanensis-Quercus griffithii (Type 3); (4) mixed evergreen broad-leaved and coniferous forest: Castanopsis orthacantha-P. yunnanensis-Schima argentea (Type 4); (5) mixed coniferous, evergreen and deciduous broad-leaved forest: Pinus yunnanensis-Schima argentea-Quercus griffithii (Type 5); (6) mixed coniferous and evergreen broad-leaved forest: Pinus armandii-Quercus rehderiana-Pinus yunnanensis (Type 6). The size- and age-structure and regeneration patterns of P. yunnanensis were highly variable within these six forest types. P. yunnanensis regeneration was well balanced in forest Type 1 as compared to the other five types. All six forest types were identified as rare and old-growth with P. yunnaensis trees reaching ages of more than 105 years (a maximum age of 165 years with a diameter 116 cm at breast height) except for the Type 4 forest (a 90-year-old stand). Growth rates of P. yunnanensis, based upon ring width measurements, were high for the first 10 years, then declined after the 10th year. In contrast, basal area increment (BAI) increased for the first 25 years, plateaued, and only declined as trees became older. Trees in the older age classes grew more quickly than younger trees at the same age, a consequence of either site quality or competitive differences. The BAI of P. yunnanensis in all age classes in the Tianchi National Nature Reserve was much higher than those of the secondary and degraded natural P. yunnanensis forests of other areas. Conclusions: The P. yunnanensis forests of the Tianchi area appear to be some of the last remnants of primeval and old-growth forests of this species. These forests are structurally diverse and contain a rich diversity of overstory, mid-story, and understory species. Taxonomic reference: Editorial Committee of Flora Republicae Popularis Sinicae (1959–2004) for vascular plants. Abbreviations: BA = basal area; BAI = basal area increment; DBH = diameter at breast height; H = height; RBA = relative basal area. more...
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- 2020
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3. Species richness, forest types and regeneration of Schima in the subtropical forest ecosystem of Yunnan, southwestern China
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Cindy Q. Tang, Peng-Bin Han, Shuaifeng Li, Li-Qin Shen, Diao-Shun Huang, Yun-Fang Li, Ming-Chun Peng, Chong-Yun Wang, Xiao-Shuang Li, Wei Li, Wei Wang, and Zhi-Ying Zhang
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Forest structure ,Regeneration dynamics ,Schima ,Species richness ,Forest succession ,Yunnan ,Ecology ,QH540-549.5 - Abstract
Abstract Background Schima genus of Theaceae is confined to subtropics and tropics of South, East and Southeast Asia. Thirteen species of Schima are distributed in subtropical China. Many of them appear as dominant canopy species in the subtropical forests. To date, Schima species richness distribution patterns of China have remained unknown. Meanwhile, there has been a longtime debate as to whether forests dominated by Schima species are early or late successional forests. We aim to clarify Schima species richness patterns and these species’ roles in the forest succession and regeneration dynamics of the subtropical ecosystem in Yunnan Province, China. Method We mapped Schima species richness distribution patterns in China. Based on 71 vegetation plots, we analyzed forest characteristics, population structure, and regeneration dynamics of Schima species in Yunnan. Results Yunnan was found to harbor the greatest richness and the highest rarity-weighted richness of Schima species in the subtropical regions of China. We classified five primary and six secondary forest types containing Schima species as one of dominants. Yunnan had the high floristic diversity and varying stand structure of forests containing Schima species. The Schima species studied generally had a sporadic regeneration type and a long life-span. Four species (Schima argentea, Schima villosa, Schima sinensis, Schima sericans) were shade-intolerant. But three species (Schima noronhae, Schima khasiana and Schima wallichii) were considered as bi-modal type species having shade-intolerant and shade-tolerant traits. Schima noronhae was seen to be a top dominant in late successional forests, while S. wallichii was found as a top-dominant in early or middle or late successional forests. S. khasiana, Schima villosa, Schima sinensis usually appeared as a top dominant in early or middle successional secondary forests, though they also presented as a second dominant in late-successional forests. Schima argentea and Schima sericans dominated only in the early or middle/seral successional forests. Schima species’ regeneration establishment depended mainly on forest canopy gap formation through moderate human and natural disturbances. Conclusions Yunnan has high species richness and rarity-weighted richness of Schima. Both moderate human and natural disturbances have provided regeneration niches for Schima species. Some of the Schima species studied as a second dominant (rare as the top-dominant) present in the late-successional forests. Some of them are more often as the top-dominant in early or middle successional forests, where as time goes by the dominance of Schima species would be replaced by their associated dominant taxa such as Castanopsis species. more...
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- 2020
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4. Effects of climate change on the potential distribution of the threatened relict Dipentodon sinicus of subtropical forests in East Asia: Recommendations for management and conservation
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Cindy Q. Tang, Haruka Ohashi, Tetsuya Matsui, Sonia Herrando-Moraira, Yi-Fei Dong, Shuaifeng Li, Peng-Bin Han, Diao-Shun Huang, Li-Qin Shen, Yun-Fang Li, and Jordi López-Pujol
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Dipentodon sinicus ,Ecological niche modeling ,Global warming ,Potential habitat ,Protected areas ,Southwestern China ,Ecology ,QH540-549.5 - Abstract
Dipentodon sinicus Dunn. (Dipentodonaceae) is a rare and threatened relict plant species usually found co-dominating with other relict plants in subtropical forest patches in highly fragmented habitats of southwestern China, northern Vietnam and northeastern Myanmar of East Asia. To date, its management and conservation strategies in the light of climate change have not been explored. We evaluated effects of climate change on the distribution of climatically suitable areas of D. sinicus as found prevailing during the last glacial maximum (LGM), the mid-Holocene and the present time, and predicted the distribution of climatically suitable habitats in 2070 throughout East Asia. The results as derived from ecological niche modeling (ENM) show the current distribution to be limited to the prehistoric (the mid-Holocene and LGM) refugia, and to indicate decreasing probability of presence and a reducing range of distribution for 2070. In addition, the suitable areas predicted with high probability (0.5–1) only account for on average 9.8% of the total area of potential habitats (threshold‒1) among the models for the year 2070, thereby indicating that D. sinicus is highly vulnerable. Under all the future scenarios for the year 2070, 69–74.2% of potential habitats in China would be outside protected areas. We assess and propose priorities for protected areas, and provide suggestions for conservation management strategies. more...
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- 2020
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5. Spin- and Valley-Dependent Electronic Structure in Silicene Under Periodic Potentials
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Wei-Tao Lu, Yun-Fang Li, and Hong-Yu Tian
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Silicene ,Energy band ,Valley polarization ,Spin polarization ,Materials of engineering and construction. Mechanics of materials ,TA401-492 - Abstract
Abstract We study the spin- and valley-dependent energy band and transport property of silicene under a periodic potential, where both spin and valley degeneracies are lifted. It is found that the Dirac point, miniband, band gap, anisotropic velocity, and conductance strongly depend on the spin and valley indices. The extra Dirac points appear as the voltage potential increases, the critical values of which are different for electron with different spins and valleys. Interestingly, the velocity is greatly suppressed due to the electric field and exchange field, other than the gapless graphene. It is possible to achieve an excellent collimation effect for a specific spin near a specific valley. The spin- and valley-dependent band structure can be used to adjust the transport, and perfect transmissions are observed at Dirac points. Therefore, a remarkable spin and valley polarization is achieved which can be switched effectively by the structural parameters. Importantly, the spin and valley polarizations are greatly enhanced by the disorder of the periodic potential. more...
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- 2018
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6. System Unbalance Analyses and Improvement for Rooftop Photovoltaic Generation Systems in Distribution Networks
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Rong-Ceng Leou, Jen-Hao Teng, Yun-Fang Li, Wei-Min Lin, and Yu-Hung Lin
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Rooftop Photovoltaic Generation Systems ,system unbalance ,On Load Tap Changer ,stochastic analyses ,optimal phase arrangement ,Technology - Abstract
This paper studies the system unbalance caused by rooftop Photovoltaic Generation Systems (PVGSs) in distribution networks and proposes an improved method. The voltage and current unbalance studies for three extreme cases considering all rooftop PVGSs being connected to one single phase and then the stochastic analyses for the integration cases of rooftop PVGSs are considered. These three extreme cases lead to severe system unbalance problems. An improving method that combines the On Load Tap Changer (OLTC) and the optimal phase arrangement of distribution transformers is proposed in this paper to mitigate the system unbalance. The OLTC-based improving method is applied first. If the system unbalance is still out of range, the optimal phase arrangement of distribution transformers is further used to mitigate the system unbalance problem. The objective function of optimal phase arrangement is to minimize the system unbalance with the constraints of voltage limits, line flow limit, etc. Test results show that the proposed method can improve the system unbalance significantly even under very extreme cases. more...
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- 2020
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7. Forest characteristics and population structure of a threatened palm tree Caryota obtusa in the karst forest ecosystem of Yunnan, China
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Cindy Q Tang, Xia Lu, Min-Rui Du, Shu-Li Xiao, Shuaifeng Li, Peng-Bin Han, Jia-Le Zeng, Jian-Ran Wen, Shi-Qian Yao, You-Cai Shi, Yun-Fang Li, Ming-Chun Peng, Chong-Yun Wang, and Zhi-Ying Zhang
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Ecology ,Plant Science ,Ecology, Evolution, Behavior and Systematics - Abstract
Caryota obtusa of Arecaceae is a fascinating palm tree native to southwestern China, India, Myanmar, Thailand, Laos and Vietnam. It is an economically important and threatened species and appears as a canopy dominant in some karst areas in Yunnan. We aim to clarify the forest structure, species diversity, population status and regeneration dynamics of C. obtusa in the karst forest ecosystem of Yunnan, China. We established 56 vegetation plots dominated by C. obtusa in 10 counties of southern Yunnan. Based on the plot data, we analyzed the community stratification, floristic composition and C. obtusa’s population structure. We used questionnaires to interview local people and recorded the human activity history in C. obtusa-dominated forests. Caryota obtusa palm forests were distributed on limestone mountain slopes and gullies. There were seven forest community types. The stratification of each community included arborous layer, shrub layer and understory. The communities had rich species composition. For all the plots as a whole of each community type, Shannon–Wiener diversity index of either woody or herbaceous species ranged from 2.1 to 3.8. The diameter at breast height (DBH)-class frequency distribution of C. obtusa was a multimodal type. The regeneration was sporadic and dependent on intermediate natural disturbances. In the current population structure, a number of C. obtusa trees with small DBHs consisted mainly of the forest communities with no or a slight degree of human disturbances. Intensive human activities terribly hindered recruitment of C. obtuse, followed by the medium intensity of human activities. more...
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- 2021
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8. Forest characteristics, population structure and growth trends of Pinus yunnanensis in Tianchi National Nature Reserve of Yunnan, southwestern China
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Diao-Shun Huang, Cindy Q. Tang, Li-Qin Shen, Peng-Bin Han, Kun Song, Long-Yun Yin, Zhi-Ying Zhang, Hui-Ming Xu, Shuaifeng Li, Yun-Fang Li, and Rui-He Yin
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0106 biological sciences ,Pinus yunnanensis ,lcsh:GE1-350 ,010504 meteorology & atmospheric sciences ,biology ,Population structure ,Forestry ,biology.organism_classification ,01 natural sciences ,Geography ,Age-class basal area increment forest stratification growth rate old-growth forest regeneration pattern species diversity ,China ,National nature reserve ,lcsh:Environmental sciences ,010606 plant biology & botany ,0105 earth and related environmental sciences - Abstract
Aims: Pinus yunnanesis is commercially, culturally and economically important, but there is a lack of ecological data on its role in stand dynamics. Our aims are to clarify the structure, composition, regeneration and growth trends of primary mature P. yunnanensis forests. Study area: The Tianchi National Nature Reserve in the Xuepan Mountains, Yunlong County, northwestern Yunnan, China. Methods: We investigated forests containing P. yunnanensis, measured tree ages and analyzed the data. Results: Six forest types were identified: (1) coniferous forest: Pinus yunnanensis (Type 1); (2) mixed coniferous and evergreen broad-leaved forest: P. yunnanensis-Lithocarpus variolosus (Type 2); (3) mixed coniferous and deciduous broad-leaved forest: P. yunnanensis-Quercus griffithii (Type 3); (4) mixed evergreen broad-leaved and coniferous forest: Castanopsis orthacantha-P. yunnanensis-Schima argentea (Type 4); (5) mixed coniferous, evergreen and deciduous broad-leaved forest: Pinus yunnanensis-Schima argentea-Quercus griffithii (Type 5); (6) mixed coniferous and evergreen broad-leaved forest: Pinus armandii-Quercus rehderiana-Pinus yunnanensis (Type 6). The size- and age-structure and regeneration patterns of P. yunnanensis were highly variable within these six forest types. P. yunnanensis regeneration was well balanced in forest Type 1 as compared to the other five types. All six forest types were identified as rare and old-growth with P. yunnaensis trees reaching ages of more than 105 years (a maximum age of 165 years with a diameter 116 cm at breast height) except for the Type 4 forest (a 90-year-old stand). Growth rates of P. yunnanensis, based upon ring width measurements, were high for the first 10 years, then declined after the 10th year. In contrast, basal area increment (BAI) increased for the first 25 years, plateaued, and only declined as trees became older. Trees in the older age classes grew more quickly than younger trees at the same age, a consequence of either site quality or competitive differences. The BAI of P. yunnanensis in all age classes in the Tianchi National Nature Reserve was much higher than those of the secondary and degraded natural P. yunnanensis forests of other areas. Conclusions: The P. yunnanensis forests of the Tianchi area appear to be some of the last remnants of primeval and old-growth forests of this species. These forests are structurally diverse and contain a rich diversity of overstory, mid-story, and understory species. Taxonomic reference: Editorial Committee of Flora Republicae Popularis Sinicae (1959–2004) for vascular plants. Abbreviations: BA = basal area; BAI = basal area increment; DBH = diameter at breast height; H = height; RBA = relative basal area. more...
- Published
- 2020
9. Systematic Effectiveness Assessment Methodology for Fault Current Indicators Deployed in Distribution Systems
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Jen-Hao Teng, Chia-Hung Hsieh, Shang-Wen Luan, Bo-Ren Lan, and Yun-Fang Li
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fault current indicator ,fault management system ,failure rate ,probability density function ,communication route tracking ,Technology - Abstract
Fault Current Indicators (FCIs) with communication interfaces have been widely used in distribution systems to reduce fault-finding time. The effectiveness of a Fault Management System (FMS) composed of FCIs greatly depends on the performance of the communication network deployed by the FCIs and the failure rates of distribution systems. The conventional techniques only focus on the issues of optimal number and location of FCIs or communication network deployment individually; therefore, the effectiveness of an FMS cannot be assessed realistically. A systematic effectiveness assessment methodology for FMS considering the performance of the communication network deployed by the FCIs and the failure rates of distribution systems is vital and is investigated in this paper. A communication evaluation platform is designed in this paper and used to acquire the field measurements of communication parameters. The communication parameters, especially the Packet Success Rate (PSR), between two adjacent FCIs are measured, and the Probability Density Function (PDF) of the PSR can be built accordingly. The effectiveness of the FMS is then assessed by stochastic analysis considering the failure rates of the distribution system and PSR PDFs between two adjacent FCIs. Due to the characteristics of easy installation, maintenance, longer battery life, lower cost, and so on of ZigBee, the ZigBee-based FCI is mainly discussed in this paper. In order to efficiently find the communication route when a fault occurs, a fast communication route tracking method is also proposed in this paper and its feasibility is demonstrated in an actual distribution system. Experimental and simulation results demonstrate the validity of the proposed systematic effectiveness assessment methodology for an FMS composed of FCIs. The proposed assessment methodology can more realistically react to the actual conditions of the FMS and therefore save on installation time and costs. more...
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- 2018
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10. Forest and population structure and regeneration dynamics of relict Dipentodon sinicus in southwestern China
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Cindy Q. Tang, Diao-Shun Huang, Peng-Bin Han, Li-Qin Shen, Yun-Fang Li, Shuaifeng Li, Qian Chen, and Zhi-Ying Zhang
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forest features ,species diversity ,lcsh:Biology (General) ,regeneration ,dipentodon sinicus ,habitat ,population structure ,age structure ,lcsh:QH301-705.5 - Abstract
Dipentodon sinicus is an extant relict plant of East Asia. It is a small deciduous broad-leaved tree, the sole surviving representative of the Dipentodonaceae. We investigated forest features, population structure, and regeneration dynamics of forest stands containing this species in Caojian Forest Station of Yunnan Province and Yushe National Forest Parks of Guizhou Province, southwestern China. We identified six forest types: Carpinus kweichowensis-Liquidambar formosana-Lithocarpus glaber-Dipentodon sinicus forest (Type 1); Illicium simonsii-Salix matsudana-Schima khasiana-Dipentodon sinicus forest (Type 2); Dipentodon sinicus forest (Type 3); Dipentodon sinicus-Schima khasiana forest (Type 4); Dipentodon sinicus-Tetracentron sinense forest (Type 5); Pterocarya macroptera var. delavayi-Tetracentron sinense-Populus yunnanensis-Salix matsudana forest (Type 6). Among the six forest types, D. sinicus forest (Type 3) had the lowest values in species richness, Shannon-Wiener and Simpson’s diversity indices. The maximum age of D. sinicus was 54 years, reaching 34 cm DBH, with 14 m maximum height. Its frequency distribution in DBH-and age-class displayed a sporadic pattern in various forests. Its regeneration was more active in D. sinicus forest (Type 3), Dipentodon sinicus-Tetracentron sinense forest (Type 5), and Carpinus kweichowensis-Liquidambar formosana-Lithocarpus glaber-Dipentodon sinicus forest (Type 1) than that in the other forests (Types 2, 4 and 6). D. sinicus’ growth rate generally fluctuated from 1.15 to 5.62 mm/year. Its regeneration modes were seedlings and sprouts. Its seedling establishment depends on forest gaps formation by disturbances. It is clear that the population persistence of D. sinicus was maintained in habitats where natural disturbances were frequent. more...
- Published
- 2019
11. Effects of climate change on the potential distribution of the threatened relict Dipentodon sinicus of subtropical forests in East Asia: Recommendations for management and conservation
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Jordi López-Pujol, Yi-Fei Dong, Diao-Shun Huang, Haruka Ohashi, Peng-Bin Han, Cindy Q. Tang, Shuaifeng Li, Tetsuya Matsui, Sonia Herrando-Moraira, Li-Qin Shen, Yun-Fang Li, Yunnan University, Ministry of Education of the People's Republic of China, Generalitat de Catalunya, Yunnan Province, and Environmental Restoration and Conservation Agency (Japan) more...
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0106 biological sciences ,Dipentodon sinicus ,Range (biology) ,Climate change ,Subtropics ,010603 evolutionary biology ,01 natural sciences ,Effects of global warming ,lcsh:QH540-549.5 ,Potential habitat ,Ecology, Evolution, Behavior and Systematics ,Nature and Landscape Conservation ,Ecology ,biology ,010604 marine biology & hydrobiology ,Global warming ,biology.organism_classification ,Dipentodon ,Environmental niche modelling ,Protected areas ,Geography ,Habitat ,Southwestern China ,Threatened species ,Ecological niche modeling ,lcsh:Ecology - Abstract
Dipentodon sinicus Dunn. (Dipentodonaceae) is a rare and threatened relict plant species usually found co-dominating with other relict plants in subtropical forest patches in highly fragmented habitats of southwestern China, northern Vietnam and northeastern Myanmar of East Asia. To date, its management and conservation strategies in the light of climate change have not been explored. We evaluated effects of climate change on the distribution of climatically suitable areas of D. sinicus as found prevailing during the last glacial maximum (LGM), the mid-Holocene and the present time, and predicted the distribution of climatically suitable habitats in 2070 throughout East Asia. The results as derived from ecological niche modeling (ENM) show the current distribution to be limited to the prehistoric (the mid-Holocene and LGM) refugia, and to indicate decreasing probability of presence and a reducing range of distribution for 2070. In addition, the suitable areas predicted with high probability (0.5–1) only account for on average 9.8% of the total area of potential habitats (threshold‒1) among the models for the year 2070, thereby indicating that D. sinicus is highly vulnerable. Under all the future scenarios for the year 2070, 69–74.2% of potential habitats in China would be outside protected areas. We assess and propose priorities for protected areas, and provide suggestions for conservation management strategies., This study received financial support from Science and Technology Department of Yunnan University, China (2019YNU002), the Ministry of Science and Technology of China (2015FY210200-15), Ajuts a Grups de Recerca Consolidats” (grants nos. 2014-SGR514-GREB and 2017-SGR1116) from the Generalitat de Catalunya (Spain), Applied Basic Research Foundation of Yunnan Province, China (Grant No. 2019FB058), the Environment Research and Technology Development Fund (JPMEERF15S11407) of the Environmental Restoration and Conservation Agency of Japan, and the Kakenhi Grant Number 15H02833., Highlights Abstract Keywords 1. Introduction 2. Material and methods 2.1. Species 2.2. Occurrence data and ecological niche modeling 3. Results 3.1. Model performance and present potential distribution 3.2. Projected distribution during the mid-Holocene (ca. 6000 yr BP) and LGM (ca. 21,000 yr BP) 3.3. Projected distribution under future climate (2070) 4. Discussion 4.1. Effects of climate change on spatial distribution patterns of D. sinicus 5. Recommendations for future conservation efforts and management Declaration of competing interest Acknowledgements Appendix A. Supplementary data References more...
- Published
- 2020
12. Depsidone and xanthones from Garcinia xanthochymus with hypoglycemic activity and the mechanism of promoting glucose uptake in L6 myotubes
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Qing-Hua Liu, Guangzhong Yang, Mingrui Xiong, Ping Zhao, Yanze Fu, Liu Liu, Kuan Shi, Yu Chen, Yun-Fang Li, Hui Liu, and Yuxiu Xiao
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0301 basic medicine ,Cell Survival ,Xanthones ,Glucose uptake ,Muscle Fibers, Skeletal ,Clinical Biochemistry ,Pharmaceutical Science ,Depsides ,01 natural sciences ,Biochemistry ,Lactones ,Structure-Activity Relationship ,03 medical and health sciences ,chemistry.chemical_compound ,Drug Discovery ,Xanthone ,medicine ,Animals ,Hypoglycemic Agents ,Protein kinase A ,Garcinia ,Molecular Biology ,Protein kinase B ,Cells, Cultured ,PI3K/AKT/mTOR pathway ,Dose-Response Relationship, Drug ,Molecular Structure ,biology ,010405 organic chemistry ,Chemistry ,Organic Chemistry ,biology.organism_classification ,Rats ,0104 chemical sciences ,Glucose ,030104 developmental biology ,Mechanism of action ,biology.protein ,Molecular Medicine ,medicine.symptom ,GLUT4 - Abstract
Garcinia xanthochymus is a widely used folk medicine in southwestern China. Previous studies indicated it possesses potential anti-diabetic activities both in vitro (Fu et al., 2014; Nguyen et al., 2017) and in vivo (Shivanand et al., 2017). To discover bioactive ingredients from it and unveil their mechanism of action against diabetes, the present study was designed to isolate constituents from extract of G. xanthochymus, determine their structures, screen their activities and investigate mechanism of action of the active substances. Twenty compounds including a new depsidone named garciniadepsidone A (20) and 19 known xanthones were obtained. All of them were screened to discover the active compounds with anti-diabetic activities. Finally, three xanthones including 12b-hydroxy-des-d-garcigerrin (5), 1,2,5,6-tretrahydroxy-4-(1,1-dimethyl-2-propenyl)-7-(3-methyl-2-butenyl) xanthone (13) and 1,5,6-trihydroxy-7,8-di(3-methyl-2-butenyl)-6',6'-dimethylpyrano (2',3':3,4) xanthone (18) were found to be able to significantly stimulate the glucose uptake in the skeleton muscle cells. The effects of the three compounds were comparable to those of insulin and metformin. Based on molecular mechanistic study, it was found that both of compound 5 and 13 promoted glucose uptake by activating phosphatidylinositol-3 kinase (PI3K)/the serine/threonine kinase protein kinase B (PKB/Akt) signaling pathway and AMP-activated protein kinase (AMPK) signaling pathway, resulting in the translocation of GLUT4 in L6 myotubes without affecting the expression of GLUT4. Compound 5 and 13 have great potential to be developed as promising leads to target diabetes. more...
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- 2017
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13. Screening of inhibitors of glycogen synthase kinase-3β from traditional Chinese medicines using enzyme-immobilized magnetic beads combined with high-performance liquid chromatography
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Yuxiu Xiao, Yu Chen, Yun-Fang Li, Zhinan Mei, and Jia Xu
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Immobilized enzyme ,Biochemistry ,High-performance liquid chromatography ,Analytical Chemistry ,Glycogen Synthase Kinase 3 ,Biflavonoids ,Enzyme kinetics ,Enzyme Inhibitors ,Phosphorylation ,Binding site ,Glycogen synthase ,Chromatography, High Pressure Liquid ,chemistry.chemical_classification ,Glycogen Synthase Kinase 3 beta ,Chromatography ,biology ,Chemistry ,Magnetic Phenomena ,Organic Chemistry ,Substrate (chemistry) ,General Medicine ,Enzymes, Immobilized ,Enzyme assay ,Molecular Docking Simulation ,Kinetics ,Enzyme ,biology.protein ,Peptides ,Drugs, Chinese Herbal - Abstract
Glycogen synthase kinase-3β (GSK-3β) was immobilized on magnetic beads (MBs) by affinity method for the first time. The enzyme-immobilized MBs were coupled with high-performance liquid chromatography-ultraviolet (HPLC-UV) technique to establish a cost-effective and reliable method for screening of inhibitors of GSK-3β. A peptide substrate of GSK-3β containing a tyrosine residue was employed since it can be sensitively detected by UV detector at 214nm. The substrate and its phosphorylated product were separated by baseline within 10min. The enzyme activity was determined by the quantification of peak area of the product. Parameters including enzyme immobilization, enzyme reaction and the performance of immobilized-enzyme were investigated. The immobilized enzyme can be reused for 10 times and remain stable for 4 days at 4°C. The inhibitory activities of extracts of 15 traditional Chinese medicines (TCMs) were screened. As a result, three of them including Euonymus fortunei, Amygdalus communis and Garcinia xanthochymus were found possessing high inhibitory activities (inhibition rate >90%). From G. xanthochymus, a new inhibitor of GSK-3β, fukugetin, was discovered with an IC50 value of 3.18±0.07μM. Enzyme kinetics and molecular docking experiments further revealed the inhibitory mechanism, indicating fukugetin was a non-ATP competitive inhibitor interacting with the phosphate recognizing substrate binding site of GSK-3β. more...
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- 2015
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14. Theoretical Study of Iron Heterogeneous Growth on the Surface of C60 Molecule
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Qi Cheng Liu and Yun Fang Li
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Crystal ,Crystallography ,Molecular dynamics ,Covalent bond ,law ,Chemistry ,Clathrate hydrate ,General Engineering ,Nucleation ,Molecule ,Icosahedron ,Crystallization ,law.invention - Abstract
Direct molecule dynamics (MD) simulations have also been performed to study heterogeneous nucleation and growth of iron on C60 molecule. The grown mechanism of this crystallization process was explored. The results indicate that 92 iron atoms attach to C60 molecule surface can form new covalent bond, forming a closed regular icosahedron. More atoms grow in layer to form bigger regular closed clathrate base on the structure of former one. As increase of atoms number, there will appear some crystal faces. more...
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- 2014
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15. Wide-Angle Behaviors of Sub-Wavelength Metal Gratings as Polarizing Beam Splitters
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Yun Fang Li and Chang Xi Xue
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Materials science ,Extinction ratio ,business.industry ,Filling factor ,Mechanical Engineering ,Grating ,law.invention ,Wavelength ,Optics ,Mechanics of Materials ,law ,Etching ,Optoelectronics ,General Materials Science ,Thin film ,business ,Absorption (electromagnetic radiation) ,Beam splitter - Abstract
A second-order effective medium theory (second-order EMT) and thin film theory have been used to design a polarizing beam splitter (PBS) composed of one-dimensional sub-wavelength metal grating, considering the material of metal to be copper (Cu). It was analyzed by the finite difference time domain method for the wavelength of 1500nm. A high extinction ratio in transmission (>55.71dB) over abroad interval of angles of incidence ([-60o, 60o]) is achieved with the depth and the filling factor of the grating chosen to be 350nm and 0.3762, which are selected to transmit TM polarized light and reflect TE polarized light as much as possible at normal incident. The loss of the TE polarized light for the Cu structures is approximately less than 5.55% due to the absorption of Cu in a large angle range. The desired property will enable this type of polarizing beam splitter to be used in diverging beams. When the PBS needs to transmit approximately 25% of the TE polarized light and as much as possible the TM polarized light, it can be used in magneto-optical data storage head. But the depth of grating has been changed (approximately d=40nm) and TM transmission is only 94.7%. But it can be further improved (from 94.7% to 97.97%) by etching into the substrate. more...
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- 2013
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16. [Chemical constituents from leaves of Garcinia xanthochymus]
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Liu Liu, Yun-Fang Li, Guangzhong Yang, Yu Chen, and Fei Gan
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biology ,Phytochemicals ,Ethyl acetate ,biology.organism_classification ,High-performance liquid chromatography ,Terpene ,Plant Leaves ,chemistry.chemical_compound ,Acetic acid ,Complementary and alternative medicine ,chemistry ,Glucoside ,Xanthone ,Pharmacology (medical) ,General Pharmacology, Toxicology and Pharmaceutics ,Garcinia ,Kaempferol ,Chromatography, High Pressure Liquid ,Nuclear chemistry - Abstract
The constituents were isolated and purified by the silica gel and semi-preparative HPLC, and their structures were elucidated by NMR spectral and MS data. Fifteen compounds were isolated from the ethyl acetate fraction of 95% ethanol extract from the leaves of Garcinia xanthochymus, and identified as 5, 7, 4'-trihydroxy-6-(3-hydroxy-3-methylbutyl)-flavone(1), 1,5-dihydroxy-3-methoxyxanthone(2), 1, 3-dimethoxy-5-hydroxy xanthone(3), kaempferol(4),(2S,3S)-trans-dihydrokaempferol(5), 3, 24, 25-trihydroxytirucall-7-ene(6), 4-hydroxycinnamic acid(7), isovanillic acid(8),(Z)-2-(2,4-dihydroxy-2, 6, 6-trimethylcyclohexylidene)acetic acid(9), volkensiflavone(10), morelloflavone(11), 3, 8″-biapigenin(12), bilobetin(13), fukugiside(14), GB2a glucoside(15). Compound 1 is a new compound, compounds 5, 6, 9 and 13 are isolated from the genus Garcinia for the first time, and compounds 4, 7-8, 10-12, 14 and 15 are firstly found from this plant. α-Amylase inhibitory activities of 10 compounds were determined using starch azure as the substrate, and the results show that compound 13 has the inhibitory activities against α-amylase, IC₅₀ values of compound 13 and acarbose are 8.12, 4.32 μmol•L⁻¹ respectively. more...
- Published
- 2016
17. Frequent occurrence of unreduced gametes in Triticum turgidum–Aegilops tauschii hybrids
- Author
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Yun-Fang Li, Qi Jiang, You-Liang Zheng, Yang Yen, Ze-Hong Yan, Ya-Qing Ye, Lianquan Zhang, Shou-Fen Dai, and Dengcai Liu
- Subjects
Genetics ,biology ,Chromosome ,Plant Science ,Horticulture ,Subspecies ,biology.organism_classification ,Meiosis ,Botany ,Aegilops tauschii ,Common wheat ,Ploidy ,Agronomy and Crop Science ,Gene ,Hybrid - Abstract
Spontaneous chromosome doubling via union of unreduced (2n) gametes has been thought to be the way that common wheat (Triticum aestivum L.) was originated from the hybridization of T. turgidum L. with Ae. tauschii Cosson. Previous works have observed unreduced gametes in F1 hybrids of Ae. tauschii with six of the eight T. turgidum subspecies. It is not clear, however, whether the formation of these unreduced gametes is a norm in the F1 hybrids. In the present study, we tried to answer this question by assessing the occurrence frequency of unreduced gametes in 115 T. turgidum–Ae. tauschii hybrid combinations, involving 76 genotypes of seven T. turgdium subspecies and 24 Ae. tauschii accessions. Our data show that these hybrid combinations differed significantly (P ≤ 0.01, F = 11.40) in selfed seedset, an indicator for production of unreduced gametes. This study clearly showed that meiotic restitution genes are widely distributed within T. turgidum. However, significant differences were found between as well as within T. turgidum subspecies and in the interaction of the T. turgidum genotypes with those of Ae. taushii. The possible application of the meiotic restitution genes from T. turgidum in production of double haploids is also discussed. more...
- Published
- 2009
- Full Text
- View/download PDF
18. Forest characteristics, population structure and growth trends of Pinus yunnanensis in Tianchi National Nature Reserve of Yunnan, southwestern China.
- Author
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Tang, Cindy Q., Li-Qin Shen, Peng-Bin Han, Diao-Shun Huang, Shuaifeng Li, Yun-Fang Li, Kun Song, Zhi-Ying Zhang, Long-Yun Yin, Rui-He Yin, and Hui-Ming Xu
- Subjects
PINUS kesiya ,PLANT growth ,NATURE reserves ,VEGETATION & climate ,FORESTS & forestry - Abstract
Aims: Pinus yunnanesis is commercially, culturally and economically important, but there is a lack of ecological data on its role in stand dynamics. Our aims are to clarify the structure, composition, regeneration and growth trends of primary mature P. yunnanensis forests. Study area: The Tianchi National Nature Reserve in the Xuepan Mountains, Yunlong County, northwestern Yunnan, China. Methods: We investigated forests containing P. yunnanensis, measured tree ages and analyzed the data. Results: Six forest types were identified: (1) coniferous forest: Pinus yunnanensis (Type 1); (2) mixed coniferous and evergreen broad-leaved forest: P. yunnanensis-Lithocarpus variolosus (Type 2); (3) mixed coniferous and deciduous broad-leaved forest: P. yunnanensis-Quercus griffithii (Type 3); (4) mixed evergreen broad-leaved and coniferous forest: Castanopsis orthacantha-P. yunnanensis-Schima argentea (Type 4); (5) mixed coniferous, evergreen and deciduous broad-leaved forest: Pinus yunnanensis-Schima argentea-Quercus griffithii (Type 5); (6) mixed coniferous and evergreen broad-leaved forest: Pinus armandii-Quercus rehderiana-Pinus yunnanensis (Type 6). The size- and age-structure and regeneration patterns of P. yunnanensis were highly variable within these six forest types. P. yunnanensis regeneration was well balanced in forest Type 1 as compared to the other five types. All six forest types were identified as rare and old-growth with P. yunnaensis trees reaching ages of more than 105 years (a maximum age of 165 years with a diameter 116 cm at breast height) except for the Type 4 forest (a 90-year-old stand). Growth rates of P. yunnanensis, based upon ring width measurements, were high for the first 10 years, then declined after the 10th year. In contrast, basal area increment (BAI) increased for the first 25 years, plateaued, and only declined as trees became older. Trees in the older age classes grew more quickly than younger trees at the same age, a consequence of either site quality or competitive differences. The BAI of P. yunnanensis in all age classes in the Tianchi National Nature Reserve was much higher than those of the secondary and degraded natural P. yunnanensis forests of other areas. Conclusions: The P. yunnanensis forests of the Tianchi area appear to be some of the last remnants of primeval and old-growth forests of this species. These forests are structurally diverse and contain a rich diversity of overstory, mid-story, and understory species. [ABSTRACT FROM AUTHOR] more...
- Published
- 2020
- Full Text
- View/download PDF
19. Forest and population structure and regeneration dynamics of relict Dipentodon sinicus in southwestern China.
- Author
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TANG, Cindy Q., Diao-Shun HUANG, Peng-Bin HAN, Li-Qin SHEN, Yun-Fang LI, Shuaifeng LI, Qian CHEN, and Zhi-Ying ZHANG
- Subjects
FOREST regeneration ,FOREST canopy gaps ,FOREST dynamics ,FOREST reserves ,DISTRIBUTION (Probability theory) ,SPECIES diversity - Abstract
Dipentodon sinicus is an extant relict plant of East Asia. It is a small deciduous broad-leaved tree, the sole surviving representative of the Dipentodonaceae. We investigated forest features, population structure, and regeneration dynamics of forest stands containing this species in Caojian Forest Station of Yunnan Province and Yushe National Forest Parks of Guizhou Province, southwestern China. We identified six forest types: Carpinus kweichowensis-Liquidambar formosana-Lithocarpus glaber-Dipentodon sinicus forest (Type 1); Illicium simonsii-Salix matsudana-Schima khasiana-Dipentodon sinicus forest (Type 2); Dipentodon sinicus forest (Type 3); Dipentodon sinicus-Schima khasiana forest (Type 4); Dipentodon sinicus-Tetracentron sinense forest (Type 5); Pterocarya macroptera var. delavayi-Tetracentron sinense-Populusyunnanensis-Salix matsudana forest (Type 6). Among the six forest types, D. sinicus forest (Type 3) had the lowest values in species richness, Shannon-Wiener and Simpson's diversity indices. The maximum age of D. sinicus was 54 years, reaching 34 cm DBH, with 14 m maximum height. Its frequency distribution in DBH-and age-class displayed a sporadic pattern in various forests. Its regeneration was more active in D. sinicus forest (Type 3), Dipentodon sinicus-Tetracentron sinense forest (Type 5), and Carpinus kweichowensis-Liquidambar formosana-Lithocarpus glaber-Dipentodon sinicus forest (Type 1) than that in the other forests (Types 2, 4 and 6). D. sinicus' growth rate generally fluctuated from 1.15 to 5.62 mm/year. Its regeneration modes were seedlings and sprouts. Its seedling establishment depends on forest gaps formation by disturbances. It is clear that the population persistence of D. sinicus was maintained in habitats where natural disturbances were frequent. [ABSTRACT FROM AUTHOR] more...
- Published
- 2019
- Full Text
- View/download PDF
20. Ca2+ participates in alpha1B-adrenoceptor-mediated cAMP response in HEK293 cells
- Author
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Youyi Zhang, Yun-fang Li, Qi-de Han, Yao Song, and Erdan Dong
- Subjects
medicine.medical_specialty ,DNA, Complementary ,Calmodulin ,G protein ,Gene Expression ,Kidney ,Transfection ,medicine.disease_cause ,Pertussis toxin ,Cell Line ,Adenylyl cyclase ,Norepinephrine ,chemistry.chemical_compound ,Receptors, Adrenergic, alpha-1 ,Internal medicine ,Cyclic AMP ,medicine ,Humans ,Pharmacology (medical) ,Channel blocker ,Protein Kinase C ,Pharmacology ,Phospholipase C ,biology ,Cholera toxin ,General Medicine ,Protein-Tyrosine Kinases ,Molecular biology ,EGTA ,Endocrinology ,chemistry ,Type C Phospholipases ,Calcium-Calmodulin-Dependent Protein Kinases ,biology.protein ,Calcium ,Signal Transduction - Abstract
Aim: To investigate the α 1B -adrenoceptor (α 1B -AR)-mediated cAMP response and underlying mechanisms in HEK293 cells. Methods: Full-length cDNA encoding α 1B -AR was transfected into HEK293 cells using the calcium phosphate precipitation method, and α 1B -AR expression and cAMP accumulation were determined by using the saturation radioligand binding assay and ion-exchange chromatography, respectively. Results: Under agonist stimulation, α 1B -AR mediated cAMP synthesis in HEK293 cells, and blockade by PLC-PKC or tyrosine kinase did not reduce cAMP accumulation induced by NE. Pretreatment with pertussis toxin (PTX) had little effect on basal cAMP accumulation as well as norepinephrine (NE)-stimulated cAMP accumulation. In addition, pretreatment with cholera toxin (CTX) neither mimicked nor blocked the effect induced by NE. The extracellular Ca 2+ chelator egtazic acid (EGTA), nonselective Ca 2+ channel blocker CdCl 2 and calmodulin (CaM) inhibitor W-7 significantly reduced NE-induced cAMP accumulation from 1.59%±0.47% to 1.00%±0.31%, 0.78%±0.23%, and 0.90%±0.40%, respectively. Conclusion: By coupling with a PTX-insensitive G protein, α 1B AR promotes Ca 2+ influx via receptor-dependent Ca 2+ channels, then Ca 2+ is linked to CaM to form a Ca 2+ -CaM complex, which stimulates adenylyl cyclase (AC), thereby increasing the cAMP production in HEK293 cell lines. more...
- Published
- 2005
- Full Text
- View/download PDF
21. Rapid screening and identification of α-amylase inhibitors from Garcinia xanthochymus using enzyme-immobilized magnetic nanoparticles coupled with HPLC and MS
- Author
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Yu Chen, Zhinan Mei, Yuxiu Xiao, Dan Chen, Yun-Fang Li, and Chuying Xiao
- Subjects
Clinical Biochemistry ,Biochemistry ,High-performance liquid chromatography ,Mass Spectrometry ,Analytical Chemistry ,chemistry.chemical_compound ,Glucoside ,Biflavonoids ,Medicinal plants ,Magnetite Nanoparticles ,Chromatography, High Pressure Liquid ,Enzyme Assays ,chemistry.chemical_classification ,Chromatography ,Chemistry ,Plant Extracts ,Cell Biology ,General Medicine ,Enzymes, Immobilized ,Garcinia xanthochymus ,NMR spectra database ,Enzyme ,Magnetic nanoparticles ,alpha-Amylases ,Garcinia - Abstract
α-Amylase inhibitors play an important role in management of diabetes and obesity. In order to rapidly discover potent α-amylase inhibitors from medicinal plants, a ligands-screening method based on enzyme-immobilized magnetic nanoparticles integrated with HPLC was developed. Amine-terminated magnetic nanoparticles were prepared for the immobilization of α-amylase. Based on the affinity theory, the α-amylase-coated magnetic nanoparticles were employed to fish out the ligands from the extracts of Garcinia xanthochymus, and the elutes were examined by HPLC. As a result, three ligands were screened out. Isolation and identification were carried out subsequently. By analyzing the UV, MS and NMR spectra, they were identified as three biflavonoids including GB2a glucoside (2), GB2a (3) and fukugetin (4). The IC50 values of the three compounds were also determined. The results suggest the proposed approach is efficient and accurate, and has great potential in rapid discovery of drug candidates from medical plants. more...
- Published
- 2014
22. Pterodontic acid
- Author
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Zhi-Nan Mei, Yun-Fang Li, Xin Yu, and Guang-Zhong Yang
- Subjects
General Materials Science ,General Chemistry ,Condensed Matter Physics - Abstract
In the title compound, C15H22O2, the C=C bond lengths in the cyclohexene ring and the allylic acid group [1.325 (3) and 1.324 (3) Å] are almost equal and are shorter than those observed in ethylene. The C=O and C—O bond lengths in the allylic acid group [1.201 (3) and 1.321 (3) Å] are almost equal to those of formic acid. There is an intramolecular hydrogen bond between the allylic acid H atom and the hydroxy O atom [C...O = 2.673 (2) Å and C—H...O = 101°]. more...
- Published
- 2006
- Full Text
- View/download PDF
23. Clinical manifestations of imaging demonstrations of AIDS-related nervous system infections
- Author
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Hong-Jun, Li, Yun-Fang, Li, Ning, Li, Hai-Feng, Mi, and Jing-Liang, Cheng
- Subjects
Diagnostic Imaging ,Acquired Immunodeficiency Syndrome ,AIDS-Related Opportunistic Infections ,Humans ,Nervous System Diseases - Published
- 2013
24. Four new lignans from Schisandra sphenanthera
- Author
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Guangzhong Yang, Jing-Fang Huang, Yun-Fang Li, and Yan Jiang
- Subjects
Stereochemistry ,Pharmaceutical Science ,Lignans ,Analytical Chemistry ,chemistry.chemical_compound ,Cyclooctanes ,Drug Discovery ,Polycyclic Compounds ,Furans ,Nuclear Magnetic Resonance, Biomolecular ,Schisandra ,Pharmacology ,Dibenzocyclooctadiene lignan ,biology ,Molecular Structure ,Chemistry ,Organic Chemistry ,Schisandra sphenanthera ,General Medicine ,biology.organism_classification ,Schisandraceae ,Complementary and alternative medicine ,Pinoresinol ,Schisantherin D ,Molecular Medicine ,Interiotherin B ,Two-dimensional nuclear magnetic resonance spectroscopy - Abstract
Three new 7,8-secolignans, schisandlignans A–C (1, 2, and 4), one new dibenzocyclooctadiene lignan, schisandlignan D (5), together with nine known lignans 3′,4′-dimethoxybenzoic acid (3″,4″-dimethoxyphenyl)-2-methyl-3-oxobutyl ester (3), gomisin J (6), rubrisandrin A(1b) (7), interiotherin B (8), schisantherin D (9), ( − )-machilusin (10), ganschisandrine (11), henricine A (12), and (+)-1-hydroxy pinoresinol (13), were isolated from the rattan of Schisandra sphenanthera. Their structures were determined by analysis of 1D and 2D NMR spectroscopic data. more...
- Published
- 2013
25. Critical influenza (H1N1) pneumonia: imaging manifestations and histopathological findings
- Author
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Hong-Jun, Li, Jing-Liang, Cheng, Ning, Li, Yun-Fang, Li, and Hui-Mao, Zhang
- Subjects
Adult ,Male ,Adolescent ,Middle Aged ,Radiography ,Young Adult ,Influenza A Virus, H1N1 Subtype ,Pregnancy ,Child, Preschool ,Influenza, Human ,Humans ,Female ,Child ,Retrospective Studies - Abstract
The global outbreak of influenza A (H1N1) has led to the Ministry of Health of China listing it as one of the A-class infectious diseases. Pneumonia is the most serious complication of influenza A, commonly causing death. Populations are ordinarily susceptible to influenza A. This study aimed to investigate the imaging manifestation features of critical influenza A (H1N1) pneumonia and to improve its diagnostic techniques.A total of seven death cases from critical influenza A (H1N1) pneumonia were retrospectively analyzed on their imaging manifestations and autopsy data. Pulmonary CT scanning was performed for five cases, with one receiving additional chest X-ray and chest CT scanning, and chest postero-anterior position X-ray examination was performed for other two. Autopsy was performed for five cases and postmortem examinations were performed for other two cases.The seven cases of influenza A showed critical manifestations in 4 - 7 days after symptoms onset, with two having basic diseases of diabetes and one being pregnant. Extensive blurry high-density shadows of bilateral lungs were found in three cases, which were most obvious in middle and inferior parts of lungs. Pulmonary CT scanning revealed bilateral flaky parenchymal shadows in peripheral, dorsal and fundus segments of the middle-inferior parts of lungs, with one case of complicated pneumothorax, atelectasis and pleural effusion and another case of thin-walled cavity and dilated bronchi shadows in the superior parts of lungs.Diagnostic imaging is an important assessing tool for critical influenza A (H1N1) pneumonia. The imaging manifestations are characteristic instead of being specific. The definitive diagnosis can be made in combination with clinical examinations and laboratory tests. more...
- Published
- 2012
26. [Terpenoids from Euphorbia antiquorum L.]
- Author
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Yu, Chen, Xue-Jun, Tian, Yun-Fang, Li, and Guang-Zhong, Yang
- Subjects
Plants, Medicinal ,Molecular Structure ,Euphorbia ,Terpenes ,Oleanolic Acid - Abstract
To study the chemical constituents of Euphorbia antiquorum L., the constituents were isolated with normal-phase and reverse-phase silica gel column chromatography and their structures were elucidated on the basis of spectroscopic data. Seven terpenoids were obtained from EtOAc extract of E. antiquoru L. They were identified as antiquorine A (1), antiquorine B (2), ent-13S-hydroxy-16-atisene-3,14-dione (3), taraxerol (4), 3beta-hydroxy-25,26,27-trisnorcycloart-24-oic acid (5), 9beta,19-cyclolanostan-3beta-ol (6) and psi-taraxastane-3,20-diol (7) by spectral analysis. Compounds 1-3 are diterpenoids, which belonged to abietane, ent-kaurane and atisane respectively. Among them, compounds 1 and 2 are new compounds. Compounds 4-7 are triterpenoids, and compound 5 is a degraded cycloartane triterpenoid which is a new natural product. Compound 7 was isolated from this plant for the first time. It demonstrated that the chemical structures of constituents in this plant were diverse. more...
- Published
- 2010
27. Terpenoids and flavonoids from Laggera pterodonta
- Author
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Guang-Zhong, Yang, Yun-Fang, Li, Xin, Yu, and Zhi-Nan, Mei
- Subjects
Flavonoids ,Spectrometry, Mass, Electrospray Ionization ,Staphylococcus aureus ,Magnetic Resonance Spectroscopy ,Plants, Medicinal ,Molecular Structure ,Terpenes ,Asteraceae ,Plant Components, Aerial ,Sitosterols ,Anti-Bacterial Agents ,Glucosides ,Pseudomonas aeruginosa ,Chromatography, Gel ,Quercetin ,Sesquiterpenes - Abstract
To study the chemical constituents of aerial parts of Laggera pterodonta (DC.) Benth., the air-dried aerial parts of this plant were powered and extracted with boiling water and purified by silica gel column chromatography and recrystallized. Eleven compounds were obtained from L. pterodonta. They were identified as to be 6-O-beta-D-glucopyranosyl-carvotanacetone (1), pterodontic acid (2), 1beta-hydroxy pterondontic acid (3), pterodontoside A (4), pterodondiol (5), pterodontriol B (6), 5-hydroxy-3,4', 6,7-tetramethoxyflavone (7), artemitin (8), chrysosplenetin B (9), quercetin (10) and beta-sitosterol (11). Compound 1 is a new monoterpene glucoside. Compounds 10 and 11 were isolated from this plant for the first time. Compounds 2 and 5 showed moderate activity against bacteria including Staphylococcus aureus, Pseudomonas aeruginosa, Bacillus subtilis, Mycobacteium phlei and Bacillus circulans by paper disc diffusion method, while they both displayed no activity against Escherichia coli. more...
- Published
- 2007
28. Plague in China 2014-All sporadic case report of pneumonic plague.
- Author
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Yun-fang Li, De-biao Li, Hong-sheng Shao, Hong-jun Li, Yue-dong Han, Li, Yun-Fang, Li, De-Biao, Shao, Hong-Sheng, Li, Hong-Jun, and Han, Yue-Dong
- Subjects
- *
PLAGUE , *YERSINIA pestis , *COMMUNICABLE diseases , *PANDEMICS - Abstract
Background: Yersinia pestis is the pathogen of the plague and caused three pandemics worldwide. Pneumonic plague is rarer than bubonic and septicemic plague. We report detailed clinical and pathogenic data for all the three sporadic cases of pneumonic plagues in China in 2014.Case Presentation: All the three patients are herders in Gansu province of China. They were all infected by Yersinia pestis and displayed in the form of pneumonic plague respectively without related. We tested patient specimens from the upper (nasopharyngeal swabs) or the lower (sputum) respiratory tract and whole blood, plasma, and serum specimens for Yersinia pestis. All patients had fever, cough and dyspnea, and for patient 2 and 3, unconscious. Respiratory symptoms were predominant with acute respiratory failure. The chest X-ray showed signs consistent with necrotizing inflammation with multiple lobar involvements. Despite emergency treatment, all patients died of refractory multiple organ failure within 24 h after admission to hospital. All the contacts were quarantined immediately and there were no secondary cases.Conclusions: Nowadays, the plague is epidemic in animals and can infect people who contact with the infected animals which may cause an epidemic in human. We think dogs maybe an intermediate vector for plague and as a source of risk for humans who are exposed to pet animals or who work professionally with canines. If a patient has been exposed to a risk factor and has fever and dyspnea, plague should be considered. People who had contact with a confirmed case should be isolated and investigated for F1 antigen analysis and receive post-exposure preventive treatment. A vaccination strategy might be useful for individuals who are occupationally exposed in areas where endemically infected reservoirs of plague-infected small mammals co-exist. [ABSTRACT FROM AUTHOR] more...- Published
- 2016
- Full Text
- View/download PDF
29. Helical Shell Structures of Ni–Al Alloy Nanowires and Their Electronic Transport Properties
- Author
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Xue-Qing, Zhang, primary, Hui, Li, additional, Kim-Meow, Liew, additional, Yun-Fang, Li, additional, and Feng-Wei, Sun, additional
- Published
- 2007
- Full Text
- View/download PDF
30. Pterodondiol
- Author
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Zhi-nan Mei, Yun-fang Li, and Guang-zhong Yang
- Subjects
General Materials Science ,General Chemistry ,Condensed Matter Physics - Published
- 2007
- Full Text
- View/download PDF
31. Frequent occurrence of unreduced gametes in Triticum turgidum– Aegilops tauschii hybrids.
- Author
-
Lian-Quan Zhang, Deng-Cai Liu, You-Liang Zheng, Ze-Hong Yan, Shou-Fen Dai, Yun-Fang Li, Qi Jiang, Ya-Qing Ye, and Yang Yen
- Subjects
GAMETES ,EMMER wheat ,AEGILOPS ,GENETIC polymorphisms ,SUBSPECIES - Abstract
Spontaneous chromosome doubling via union of unreduced (2n) gametes has been thought to be the way that common wheat ( Triticum aestivum L.) was originated from the hybridization of T. turgidum L. with Ae. tauschii Cosson. Previous works have observed unreduced gametes in F
1 hybrids of Ae. tauschii with six of the eight T. turgidum subspecies. It is not clear, however, whether the formation of these unreduced gametes is a norm in the F1 hybrids. In the present study, we tried to answer this question by assessing the occurrence frequency of unreduced gametes in 115 T. turgidum– Ae. tauschii hybrid combinations, involving 76 genotypes of seven T. turgdium subspecies and 24 Ae. tauschii accessions. Our data show that these hybrid combinations differed significantly ( P ≤ 0.01, F = 11.40) in selfed seedset, an indicator for production of unreduced gametes. This study clearly showed that meiotic restitution genes are widely distributed within T. turgidum. However, significant differences were found between as well as within T. turgidum subspecies and in the interaction of the T. turgidum genotypes with those of Ae. taushii. The possible application of the meiotic restitution genes from T. turgidum in production of double haploids is also discussed. [ABSTRACT FROM AUTHOR] more...- Published
- 2010
- Full Text
- View/download PDF
32. Ca2+ participates inα1B-adrenoceptor-mediated cAMP response in HEK293 cells.
- Author
-
Yao Song, Yun-fang Li, Er-dan Dong, Qi-de Han, and You-yi Zhang
- Subjects
ALPHA adrenoceptors ,ADRENERGIC receptors ,CYCLIC adenylic acid ,CELLULAR signal transduction ,PHOSPHOLIPASE C ,PROTEIN kinase C - Abstract
To investigate theα
1B -adrenoceptor (α1B -AR)-mediated cAMP response and underlying mechanisms in HEK293 cells.Full-length cDNA encodingα1Bbscript>-AR was transfected into HEK293 cells using the calcium phosphate precipitation method, andα 1B -AR expression and cAMP accumulation were determined by using the saturation radioligand binding assay and ion-exchange chromatography, respectively.Under agonist stimulation,α1B -AR mediated cAMP synthesis in HEK293 cells, and blockade by PLC-PKC or tyrosine kinase did not reduce cAMP accumulation induced by NE. Pretreatment with pertussis toxin (PTX) had little effect on basal cAMP accumulation as well as norepinephrine (NE)-stimulated cAMP accumulation. In addition, pretreatment with cholera toxin (CTX) neither mimicked nor blocked the effect induced by NE. The extracellular Ca2+ chelator egtazic acid (EGTA), nonselective Ca2+ channel blocker CdCl2 and calmodulin (CaM) inhibitor W-7 significantly reduced NE-induced cAMP accumulation from 1.59%±0.47% to 1.00%±0.31%, 0.78%±0.23%, and 0.90%±0.40%, respectively.By coupling with a PTX-insensitive G protein,α1B AR promotes Ca2+ influx via receptor-dependent Ca2+ channels, then Ca2+ is linked to CaM to form a Ca2+ -CaM complex, which stimulates adenylyl cyclase (AC), thereby increasing the cAMP production in HEK293 cell lines. [ABSTRACT FROM AUTHOR] more...- Published
- 2005
- Full Text
- View/download PDF
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