维普中文期刊产品整合服务
401篇 您的检索式:作者名="Xianhua"
    题名 作者 年代 出处 被引量
1Role of mantle-derived magma in genesis of early Yanshanian granites in the Nanling Range, South China: in situ zircon Hf-O isotopic constraints显示文摘Although a number of petrographic observations and isotopic data suggest that magma mixing is common in genesis of many granite plutons, it is still controversial whether the mantle-derived magmas were involved in granites. We carried out in this study a systematic analysis of in situ zircon Hf-O isotopes for three early Yanshanian intrusions dated at ca. 160 Ma from the Nanling Range of Southeast China. The Qinghu monzonite has very homogeneous zircon Hf-O isotopic compositions, εHf(t) =11.6±0.3 and δ18O=5.4‰±0.3‰. In combination with whole-rock geochemical and Sr-Nd isotopic data, the parental magma of the Qinghu monzonite were likely derived from the partial melting of recently-metasomatized, phlogopite-bearing lithospheric mantle without appreciable crustal contamination. The Lisong and Fogang granites and the mafic microgranular enclaves (MME) within the Lisong granites have a wide range of zircon Hf-O isotopic compositions, with Hf and O isotopes being negatively correlated within each pluton. The Lisong MMEs were crystallized from a mantle-derived magma, similar to the parental magma of the Qinghu monzonite, with small amount of crustal assimilation. The Lisong and Fogang granites were formed by reworking of meta-sedimentary materials by mantle-derived magmas and mixing of the mantle-and sediment-derived melts to varying degrees. It is thus concluded that these two Yanshanian granites in the Nanling Range were formed associated with growth and differentiation of continental crust.LI XianHua LI WuXian WANG XuanCe LI QiuLi LIU Yu TANG GuoQiang 2009Science China Earth Sciences2009,52,9:101
2Petrogenesis of the Neopro-terozoic bimodal volcanic rocks along the western margin of the Yangtze Block:New constraints from Hf isotopes and Fe/Mn ratios显示文摘High-precision major element and Hf isotope data are reported for the Neoproterozoic Suxiong volcanic rocks along the western margin of the Yangtze Block. These volcanic rocks have variable εHf(T) values and Fe/Mn ratios. The relatively primitive basalts have high Fe/Mn ratios and high Hf-Nd isotopic compositions, indicating that they were generated by partial melting of garnet clinopyroxene in mantle plume at high pressure. Thus, the Suxiong basalts are genetically related to the proposed Neoproterozoic super-plume. On the contrary, a few differentiated basalts have low Fe/Mn ratios and low Hf-Nd isotopic compositions. They are likely to experience assimilation-fractional crystallization process. The Suxiong rhyolites have consistent Hf and Nd model ages of 1.3―1.4 Ga. They are likely generated by shallow dehydration melting of pre-existing young arc igne-ous rocks associated with the basaltic underplating/intrusion in a continental rift.LI Xianhua QI Changshi LIU Ying LIANG Xirong TU Xianglin XlE Liewen YANG Yueheng 2005Chinese Science Bulletin2005,50,21:91
3On the genetic classification and tectonic implications of the Early Yanshanian granitoids in the Nanling Range, South China显示文摘Early Yanshanian (Jurassic) granitoids are widespread in the Nanling Range of South China, and are associated with numerous non-ferrous and rare metal mineral deposits. These granitoids consist mainly of slightly peraluminous biotite monzogranites and K-feldspar granites that are closely associated in time and space with subordinate amphibole-bearing granites and muscoviteand garnet-bearing granites. In most previous studies, the biotite-bearing granites were classified as crustal transformation-type (corresponding to the S-type) granites which were interpreted to be derived from the regional Paleoproterozoic meta-sedimentary rocks. In this paper, we re-analyze the geochemical characteristics of a number of representative Early Yanshanian Nanling granitoids. There exists a clear negative correlation between SiO2 and P2O5 for the studied granitoids. The Early Yanshanian Nanling granitoid suites (including amphibole-bearing granodiorites→biotite monzogranites→K-feldspar granites→two-mica (muscovite) granites) are metaluminous to slightly peraluminous I-type or fractionated I-type granites. They were derived predominantly from Proterozoic igneous protoliths. The juvenile crust and/or newly mantle-derived materials might also have been involved in some of these granites. In addition, the Iand fractionated I-type granites are closely associated in time and space with minor amount of A-type felsic and mafic volcanic and intrusive rocks as well as alkaline rocks. All these rocks constitute a typical assemblage of anorogenic, intraplate magmatism, suggesting a dominant lithospheric extensional regime for the Nanling Range and neighboring region during the Early Yanshanian period.LI XianHua LI WuXian LI Zheng-Xiang 2007Chinese Science Bulletin2007,52,14:179
4A Review on Casting Magnesium Alloys: Modification of Commercial Alloys and Development of New Alloys显示文摘The research and development status of casting magnesium alloys including the commercial casting alloys and the new types casting alloys are reviewed,with more attention to microstructure and mechanical properties of modified-AZ91,AM60 and WE43 alloys with various additions,and new types of low cost casting alloys and high strength casting alloys.The modification and/or refinement of Mg2 Si phase in Mg–Al–Si based casting alloys by various additions are discussed and new purifying technologies for casting magnesium alloys are introduced to improve the performance.The modified AZ81 alloy with reduced impurities is found to have the tensile strength of 280 ± 6 MPa and elongation of 16% ± 0.7%.The fatigue strength of AZ91 D alloy could be obviously improved by addition of Ce and Nd.The Mg–16Gd–2Ag–0.3Zr alloy exhibits very high tensile and yield strengths(UTS:423 MPa and YS:328 MPa);however,its elongation still needs to be improved.Fusheng Pan Mingbo Yang Xianhua Chen 2016Journal of Materials Science & Technology2016,32,12:78
5Qinghu zircon:A working reference for microbeam analysis of U-Pb age and Hf and O isotopes显示文摘Zircon is the most useful mineral for studies in U-Pb geochronology and Hf and O isotope geochemistry.Matrix effect is a major problem of the microbeam techniques such as SIMS and LA-(MC)-ICPMS.Therefore,external standardization using well-characterized natural zircon standards is fundamental for accurate microbeam measurements.While the isotopic geochronology and geochemistry laboratories equipped with microbeam analytical facilities have been increasingly established in China during the past decade,applications of the isotopic microanalysis are still limited due to shortage of available standards.We report here the Qinghu zircon as a potential new working reference for microbeam analysis of zircon U-Pb age and O-Hf isotopes.This zircon was separated from the Qinghu quartz monzonite from the western Nanling Range,Southeast China.It is fairly homogeneous in U-Pb age and Hf and O isotopes in terms of large amounts of mircobeam measurements by LA-MC-ICPMS and SIMS at the scales of 20–60 m.SIMS measurements yield consistent206Pb/238U age within analytical uncertainties with that obtained by ID-TIMS.Precise determinations of O isotopes by IRMS and Hf isotopes by solution MC-ICPMS are in good agreement with the statistical mean of microbeam measurements.We recommend U-Pb age of=159.5±0.2 Ma(2SE),18O=5.4‰±0.2‰(2SD)and176Hf/177Hf=0.283002±0.000004(2SD)as the best reference values for the Qinghu zircon.LI XianHua TANG GuoQiang GONG Bing YANG YueHeng HOU KeJun HU ZhaoChu LI QiuLi LIU Yu LI WuXian 2013Chinese Science Bulletin2013,58,36:60
6SHRIMP U-Pb zircon age,geochemistry and Nd-Hf isotope of Neoproterozoic mafic dyke swarms in western Sichuan:Petrogenesis and tectonic significance显示文摘Neoproterozoic magmatic rocks are widespread in the western margin of the Yangtze block, and their origin and genesis have significant implications for understanding the evolution of the Rodinia super- continent. However, there are currently two opposing interpretations for their petrogenesis and tectonic setting: mantle plume-related and island arc origin. To further verify these two competing models, SHRIMP U-Pb zircon age determinations and geochemical and Nd-Hf isotopic analyses are conducted on the mafic dykes in the Kangdian Rift, western Sichuan. U-Pb dating suggests that these mafic dykes were emplaced at 780―760 Ma, spatially and temporally coeval with the Kangding granitoid complex. The parental magmas of these dykes were derived from a depleted asthenosphere mantle source likely triggered by an anomalously-hot mantle plume. Despite some arc-geochemical features caused by variable degrees of contamination of young island arc crust during magma ascending and emplace- ment, they show general geochemical and Nd-Hf isotopic features similar to those of the intraplate basalts. Our results support the reconstruction model of Rodinia in which the South China block was located between Australia and Laurentia.LIN GuangChun LI XianHua LI WuXian 2007Science China Earth Sciences2007,50,1:43
7The efficacy and safety of endovascular recanalization of occluded large cerebral arteries during the subacute phase of cerebral infarction:a case series report显示文摘background Intravenous tissue plasminogen activator with or without mechanical thrombectomy during the acute phase are approved therapies for ischaemic stroke.Due to the short treatment time window(<6 hours)and often treatment failure,these patients would still have an intracranial arterial occlusion(IAO).It is unclear whether these patients can benefit from subsequent interventional recanalizationof their occluded artery in the subacute phase.In this retrospective study,we have examined the efficacy and safety in patients who have received either percutaneous transluminal angioplasty(PTA)or percutaneous transluminal angioplasty and stenting(PTAS)for IAO in the subacute phase of their stroke.Methods Patients with subacute symptomatic ischaemic stroke caused by IAO were assessed to identify the responsible artery and low perfusion areas by CT angiography,MR angiography or digital subtraction angiography.In eligible patients,a PTA or PTAS was performed to reopen the occluded artery.Regular antithrombotic therapy,use of statins,control of risk factors and rehabilitation therapy were prescribed after the procedure.All patients had regular follow-up up to 12 months.results PTA or PTAS was performed in 16 patients with cerebral infarction caused by IAO in the subacute phase.After the procedure,12 cases were recanalized,two were partially recanalized and two failed to open.One patient with left C6 segment occlusion of the carotid artery had a central retinal artery embolism after PTAS.The perioperative adverse events were 6.25%.At 3 months,the distribution of modified Rankin scale scores was 0(seven cases),1(three cases),2(five cases)and 3(one case).conclusion Selective PTA or PTAS could be performed in ischaemic stroke patients with a small infarct size and large area of hypoperfusion from an occluded large cerebral artery after the acute phase.It may improve neurological dysfunction and reduce the incidence of disability.Kangning Chen Xianhua Hou Zhenhua Zhou Guangjian Li Qu Liu Li Gui Jun Hu Shugui Shi 2017Stroke & Vascular Neurology2017,2,3:41
8Shoshonitic intrusive suite in SE Guangxi: Petrology and geochemistry显示文摘A NE-direction Mesozoic shoshonitic intrusive s黫te in SE Guangxi has been identified in terms of geological, petrological and geochemical investigations. The shoshonitic intrusives are characterized by enrichment of LILE, HFSE and LREE and no obvious Nb-Ta depletion, similar to those potassic rocks formed in within-plate and rifting environments. Unlike most shoshonitic rocks forming in arc settings, the SE Guangxi shoshonitic intrusives were likely generated during regional lithosphere extension induced by upwelling of asthenosphere mantle.LI Xianhua ZHOU Hanwen LIU Ying LEE Chi-yu SUN Min CHEN Chenhong 2000Chinese Science Bulletin2000,45,7:32
9Petrogenesis of early Yanshanian highly evolved granites in the Longyuanba area,southern Jiangxi Province:Evidence from zircon U-Pb dating,Hf-O isotope and whole-rock geochemistry显示文摘Early Yanshanian(Jurassic) granitoids are widespread in the Nanling Range,South China.Whereas large granitic batholiths commonly crop out in the center of the Nanling Range(corresponding geographically to the central and northern parts of Guangdong Province),many small stocks occur in the southern part of Jiangxi Province.Most of the small stocks are associated closely with economically significant rare-metal deposits(W,Sn,Nb,Ta).Here we report the results for biotite granites and two-mica granites from three Yanshanian stocks of the Longyuanba complex.LA-ICPMS U-Pb dating of zircon yields an age of 156.1±2.1 Ma for Xiaomubei biotite granite,and U-Pb zircon dating using SIMS yields an age of 156.7±1.2 Ma for Longyuanba-Chengjiang biotite granite and 156.4±1.3 Ma for Jiangtoudong two-mica granite.Biotite granites are silica-rich(SiO 2 =70%-79%),potassic(K 2 O/Na 2 O>1.9),and peraluminous(ASI=1.05-1.33).Associated samples are invariably enriched in Rb,Th,Pb and LREE,yet depleted in Ba,Nb,Sr,P and Ti,and their REE pattern shows a large fractionation between LREE and HREE((La/Yb) N =10.7-13.5) and a pronounced Eu negative anomaly(δEu=0.28-0.41).Two-mica granite samples are also silica-rich(SiO 2 =75%-79%),potassic(K 2 O/Na 2 O>1.2),and peraluminous(ASI=1.09-1.17).However,in contrast to the biotite granites,they are more enriched in Rb,Th,Pb and extremely depleted in Ba,Nb,Sr,P and Ti,and exhibit nearly flat((La/Yb) N =0.75-1.08) chondrite-normalized REE patterns characterized by strong Eu depletion(δEu=0.02-0.04) and clear tetrad effect(TE 1.3 =1.10-1.14).Biotite granites and two-mica granties have comparable Nd isotopic signatures,and their εNd(t) are concentrated in the 13.0 to 9.6 and 11.5 to 7.7 respectively.Their zircon Hf-O isotopes of both also show similarity(biotite granites:εHf(t)= 10.8-7.9,δ 18 O=7.98‰-8.89‰ and εHf(t)= 13.8 to 9.1,δ 18 O=8.31‰-10.08‰;two-mica granites:εHf(t)= 11.3 to 8.0,δ 18 O=7.91‰-9.77‰).The results show that both biotite and two-mica granites were derived mainly from sedimentary source rocks with a minor contribution from mantle-derived materials.In spite of some S-type characteristics,the biotite granites were formed by fractional crystallization of I-type magma and assimilation of peraluminous sedimentary rocks during their ascent to the surface.Therefore,they belong to highly fractionated I-type granites.Two-mica granites exhibit a tetrad effect in their REE patterns,but share the same isotopic features with the biotite granites,suggesting that they are highly fractionated I-type granites as well.Their Lanthanide tetrad effects may be attributed to the hydrothermal alteration by magmatic fluids that have suffered degassing at late stages.Granitic magmas undergoing fractional crystallization and wall-rock assilimation can generate highly evolved granites with no REE tetrad effect in the uni-phase system.However,in the late-stage of magmatic evolution in the multi-phase system(i.e.,magmatic-hydrothermal system),these magmas also can lead to the highly evolved granites exhibiting mew-shaped REE pattern characterized by tetrad effect as the consequence of melt-fluid and fluid-vapor fractionation,and the resultant autometasomatism.We thus suggest that the REE pattern exhibiting tetrad effect feature is an important indicator of rare metal mineralization in the early Yanshanian time in southern China,implying the metamorphism of the ore fluid.TAO JiHua LI WuXian LI XianHua CEN Tao 2013Science China Earth Sciences2013,56,6:26
10SIMS U-Pb zircon age of a tuff layer in the Meishucun section, Yunnan, southwest China: Constraint on the age of the Precambrian-Cambrian boundary显示文摘Determination of the age of the Precambrian-Cambrian boundary is critical in understanding early evolution of life on Earth. SIMS U-Pb zircon analyses of the Bed 5 tuff layer of the Meishucun section were carried out closely following the guidance of cathodoluminescence images, and the majority of analyses were conducted on the oscillatory zircon grains. Thirteen measurements yield a highly reliable Concordia U-Pb age of 536.7 ± 3.9 Ma for the Bed 5 horizon. A grand mean of 206Pb/238U age of 535.2± 1.7 Ma (MSWD = 0.53) is calculated based on 13 concordant SIMS measurements of this study and 4 nano-SIMS measurements of Sawaki et al., which is the best estimate of the deposition age of the tuff layer within Bed 5 in the Meishucun section. This age has provided a robust age constraint on the significant Precambrian-Cambrian boundary strata in southern China, which independently suggested the placement of the Precambrian-Cambrian boundary at the bottom of the Xiaowaitoushan Member (Marker A).RiXiang Zhu XianHua Li XianGuang Hou YongXin Pan Fei Wang ChengLong Deng HuaiYu He 2009Science China Earth Sciences2009,52,9:24
11Accuracy of LA-ICPMS zircon U-Pb age determination:An inter-laboratory comparison显示文摘LA-ICPMS zircon U-Pb dating has been greatly advanced and widely applied in the past decade because it is a cheap and fast technique.The internal error of LA-ICPMS zircon U-Pb dating can be better than 1%,but reproducibility(accuracy)is relatively poor.In order to quantitatively assess the accuracy of this technique,zircons from two dioritic rocks,a Mesozoic dioritic microgranular enclave(FS06)and a Neoproterozoic diorite(WC09-32),were dated independently in eight laboratories using SIMS and LA-ICPMS.Results of three SIMS analyses on FS06 and WC09-2 are indistinguishable within error and give a best estimate of the crystallization age of 132.2 and 760.5 Ma(reproducibility is^1%,2RSD),respectively.Zircon U-Pb ages determined by LA-ICPMS in six laboratories vary from 128.3±1.0 to 135.0±0.9 Ma(2SE)for FS06 and from 742.9±3.1 to777.8±4.7 Ma(2SE)for WC09-32,suggesting a reproducibility of^4%(2RSD).Uncertainty produced during LA-ICPMS zircon U-Pb analyses comes from multiple sources,including uncertainty in the isotopic ratio measurements,uncertainty in the fractionation factor calculation using an external standard,uncertainty in the age determination as a result of common lead correction,age uncertainty of the external standards and uncertainty in the data reduction.Result of our study suggests that the uncertainty of LA-ICPMS zircon U-Pb dating is approximately 4%(2RSD).The uncertainty in age determination must be considered in order to interpret LA-ICPMS zircon U-Pb data rationally.LI XianHua LIU XiaoMing LIU YongSheng SU Li SUN WeiDong HUANG HuiQing YI Keewook 2015Science China Earth Sciences2015,58,10:15
12Age of granulite from Huangtuling, Dabie Mountain:Pb-Pb dating of garnet by a stepwise dissolution technique显示文摘A new stepwise dissolution scheme, involving acids with different properties, enables the selective recovery of radiogenic and common Pb from a mineral, and makes single-mineral Pb-Pb dating possible. Garnet from a granulite sample from Huangtuling, northern Dabie Mountain yields a Pb-Pb isochron age of (1098 ± 35) Ma, which is interpreted as the timing of peak metamorphism of granulite facies.Hanwen Zhou Xianhua Li Ying Liu Zhendong You Shutian Suo Zengqiu Zhong 1999Chinese Science Bulletin1999,44,10:15
13Progress and Prospects of Salt Lake Research in China显示文摘China has unique salt lake resources, and they are distributed in the east of Eurasian salt lake subzone of the Northern Hemisphere Salt Lake Zone, mainly concentrated in the regions with modern mean annual precipitation lower than 500 mm. This paper preliminarily reviews the progress made in salt lake research in China for the past 60 years. In the research of Paleoclimate and paleoenvironment from salt lake sediments, a series of salts have been proposed to be indicators of paleoclimate, and have been well accepted by scholars. The chloride-sulfate depositional regions of the west Qaidam and the east Tarim have been revealed to be the drought center of China since the Quaternary, and more than 6 spreading stages of arid climate(salt forming) have been identified. Five pan-lake periods with highstands have been proved to exist during the late Quaternary on the Tibetan Plateau. In mineral resource prospecting and theories of the forming of salt deposits: the atlas(1:2500000) of hydrochemical zoning of salt lakes on the Tibetan Plateau has been compiled for the first time, revealing the zonal distribution and transition from carbonate type to chloride type from south to north and presenting corresponding mineral assemblages for different type of salt lakes; several large continental salt deposits have been discovered and the theory of continental potash deposition has been developed, including the salt deposition in deep basins surrounded by high mountains, the mineral deposition from multistage evolution through chains of moderate or shallow lakes with multilevels, the origin of potassium rich brines in gravel layers, and the forming of potassium deposits through the inheriting from ancient salt deposits, thus establishing the framework of 'Continental Potash Deposition Theory'; several new types of Mg-borate deposits have been discovered, including the ulexite and pinnoite bed in Da Qaidam Lake, Qinghai, the pinnoite and kurnakovite bed in Chagcam Caka, Tibet, the kurnakovite bed in Lake Nyer, and the corresponding model of borate deposition from the cooling and dissolution of boron rich brines was proposed based on principles of geology, physics and chemistry. The anti-floatation-cold crystallization method developed independently has improved the capacity of KCl production to 3 million tons per year for the Qarham, serving the famous brand of potash fertilizer products. One 1.2 million ton K-sulfate production line, the biggest in the world, has been built in Lop Nor, and K-sulfate of about 1.6 million tons was produced in 2015. Supported by the new technology, i.e. brine preparation in winter-cooling-solarization-isolation-lithium deposition from salt gradient solar pond' the highest lithium production base at Zabuye Lake(4421 m), Tibet, has been established, which is the first lithium production base in China that reaches the year production of 5000 tons of lithium carbonate. The concept of Salt lake agriculture(Salt land agriculture) has been established based on the mass growth of Dunaliella and other bacillus-algae and the occurrence of various halophytes in saltmarsh and salt saline-alkali lands, finding a new way to increase arable lands and develop related green industry in salt rich environments. Finally this paper presents some new thoughts for the further research and development on salt science, and the further progress in salt science and technology will facilitate the maturing of the interdisciplinary science 'Salinology'.ZHENG Mianping ZHANG Yongsheng LIU Xifang NIE Zhen KONG Fanjing QI Wen Jia Qingxian PU Linzhong HOU Xianhua WANG Hailei ZHANG Zhen KONG Weigang LIN Yongjie 2016Acta Geologica Sinica(English Edition)2016,90,4:15
14Effect of Nd on microstructure and mechanical properties of as-extruded Mg-Y-Zr-Nd alloy显示文摘The microstructure and mechanical properties of Mg-Y-Zr-x Nd alloys with 0–2.63 wt% Nd were investigated using optical microscopy, scanning electron microscopy, transmission electron microscopy, X-ray diffraction and tensile testing test. Results indicated that more Mg_(24)Y_5 particles and Mg_(14)Nd_2Y(β) phases were dispersed in the matrix when Nd content increased from 0 wt% to 2.63 wt% in the extruded alloys.Consequently, the nucleation of dynamic recrystallization and the volume fraction of recrystallized grains were promoted obviously. The average grain size can be refined in the range of 4.6–1.3 μm after the addition of 2.63 wt% Nd. The tensile strength of extruded alloys increased with increasing Nd content, and elongation exhibited an opposite change tendency. The extruded alloy sheet with 1.01 wt% Nd demonstrates optimal combination of strength and plasticity, i.e., the ultimate tensile strength, yield strength,and elongation were 273 MPa, 214 MPa, and 24.2%, respectively. Variations in mechanical properties are discussed on the basis of microstructure observations.Xiaoyang Xu Xianhua Chen Weiwei Du Yuxiao Geng Fusheng Pan 2017Journal of Materials Science & Technology2017,33,9:14
15In situ U-Pb dating of titanite by LA-ICPMS显示文摘Titanite is an ideal mineral for U-Pb isotopic dating because of its relatively high U,Th and Pb contents.Here,we developed a technique for U-Pb dating of titanite using the 193 nm ArF laser-ablation system and Agilent 7500a Q-ICP-MS.Standards of titanite (BLR-1 and OLT-1) and zircon (91500 and GJ-1) were dated using single spot and line raster scan analytical methods.To check the matrix effect,titanite (BLR-1) and zircon (91500) standards were analyzed as the external standards.The weighted mean 206 Pb/238 U ages of OLT-1 titanite are 1015±5 Ma (2,n=24) and 1017±6 Ma (2,n=24) by single spot and line raster scan analyses,respectively,using BLR-1 titanite as the external standard.These ages are consistent with its reference age of about 1014 Ma.However,using 91500 zircon as the external standard,the weighted mean 206 Pb/238 U ages are 917±4 Ma (2,n=24) and 927±5 Ma (2,n=24) for BLR-1 titanite,and 891±4 Ma (2,n=24) and 901±5 Ma (2,n=24) for OLT-1 titanite by single spot and line raster scan analyses,respectively.It is evident that these ages are ~12% younger than their reference values.Our results reveal that significant matrix effect does exist between different kinds of minerals during LA-ICPMS U-Pb age determination,whereas it is insignificant between same minerals.Therefore,same mineral must be used as the external standard for fractionation corrections during in situ LA-ICPMS U-Pb age analysis.In addition,we determined U-Pb ages for titanites from the Early Cretaceous Fangshan pluton,which indicates a rapid cooling history of this pluton.SUN JinFeng YANG JinHui wu FuYuan XIE LieWen YANG YueHeng LIU ZhiChao LI XianHua 2012Chinese Science Bulletin2012,57,20:14
16C_(19)-Diterpenoid alkaloid arabinosides from an aqueous extract of the lateral root of Aconitum carmichaelii and their analgesic activities显示文摘Eight new C_(19)-diterpenoid alkaloid arabinosides, named aconicarmichosides E–L(1–8), were isolated from an aqueous extract of the lateral roots of Aconitum carmichaelii(Fu Zi). Their structures were determined by spectroscopic and chemical methods including 2D NMR experiments and acid hydrolysis. Compounds 1–8, together with the previously reported four neoline 14-O-arabinosides from the same plant, represent the only examples of glycosidic diterpenoid alkaloids so far. At a dose of 1.0 mg/kg(i.p.), as compared with the black control, compounds 1, 2, and 4–6 exhibited analgesic effects with 465.6% inhibitions against acetic acid-induced writhing of mice. Structure–activity relationship was also discussed.Qinglan Guo Huan Xia Xianhua Meng Gaona Shi Chengbo Xu Chenggen Zhu Tiantai Zhang Jiangong Shi 2018Acta Pharmaceutica Sinica B2018,8,3:12
17Dietary supplementation with Clostridium butyricum improves growth performance of broilers by regulating intestinal microbiota and mucosal epithelial cells显示文摘Clostridium butyricum has been widely considered an antibiotic substitute in recent years.It can promote growth performance,improve the immune response and enhance the intestinal barrier function of the host.In the present study,1-d-old Arbor Acres(AA)broilers were fed C.butyricum(1×109 cfu/kg)for 28 d.The transcriptomic characteristics of epithelial cells of the cecal mucosa were determined by RNA-sequence,and the cecal microbiota composition was explored by 16 S ribosomal RNA gene sequencing.The changes in the intestinal mucosa of broilers were then analyzed by tissue staining.Gene Ontology(GO)annotations identified substance transport and processes and pathways that might participate in intestinal development and cell viability.Kyoto Encyclopedia of Genes and Genomes(KEGG)pathway analysis revealed that the differentially expressed genes are involved in numerous pathways related to amino acid and vitamin metabolism and antioxidant and defensive functions,among others.The relative expression of some genes associated with intestinal barrier function(claudins 2,15,19,and 23,tight junction proteins 1,2,and 3 and mucin 1)was significantly increased in the treatment group(P<0.05 or P<0.01).Moreover,the proportion of Firmicutes was higher in the C.butyricum-treated group,whereas the proportion of Proteobacteria was higher in the control group.At the genus level,the relative abundances of Butyricicoccus and Lactobacillus,among other bacteria,were increased after C.butyricum supplementation.The tissue staining analysis showed that the cecal mucosa of broilers was significantly ameliorated after the addition of C.butyricum(P<0.05 or P<0.01).These results showed that dietary supplementation with C.butyricum can enhance the antioxidant capacity,mucosal barrier function,and stabilize the cecal microbiota,resulting in improving the growth performance.Laipeng Xu Xiangli Sun Xianhua Wan Keke Li Fuchun Jian Wenting Li Ruirui Jiang Ruili Han Hong Li Xiangtao Kang Yanbin Wang 2021Animal Nutrition2021,,4:12
18Imaging superoxide flash and metabolism-coupled mitochondrial permeability transition in living animals显示文摘线粒体为精力新陈代谢和反应的氧种类(ROS ) 的生产是必要的。在未经触动的房间,呼吸线粒体展览自发的 “ superoxide flashes”,对短暂 mitochondrial 渗透转变(tMPT ) 结果的 quantal 生产 ROS 事件。这里,我们在表示 superoxide 生物传感器 mt-cpYFP 的生活老鼠在 mitochondrial superoxide 闪光和 tMPT 活动的 vivo 成像执行第一,并且表明他们联合到整个身体的葡萄糖新陈代谢。柔韧的 tMPT/superoxide 闪光活动发生在骨胳的肌肉和 anesthetized 的臀部的神经转基因的老鼠。在骨胳的肌肉,成像 tMPT/superoxide 闪光揭示了线粒体的迷宫的三维的网络同时地操作。tMPT/superoxide 闪光活动响应全身的葡萄糖挑战或胰岛素刺激澎湃,以一种显然调制频率的方式并且也在 tMPT 的 gating 模式包含移动。因此,在 tMPT 依赖的 mitochondrial ROS 的 vivo 成像,信号和 metabolism-tMPT-superoxide 的发现闪光联合标记为 mitochondrial 功能并且 ROS 处于健康和疾病发信号的学习的重要工艺、概念的进展。Huaqiang Fang Min Chen Yi Ding Wei Shang Jiejia Xu Xing Zhang Wanrui Zhang Kaitao Li Yao Xiao Feng Gao Shujiang Shang Jing-Chao Li Xiao-Li Tian Shi-Qiang Wang Jingsong Zhou Noah Weisleder Jianjie Ma Kunfu Ouyang Ju Chen Xianhua Wang Ming Zheng Wang Wang Xiuqin Zhang Heping Cheng 2011Cell Research2011,21,9:11
19Randomized controlled multicenter clinical trial for integrated treatment of community-acquired pneumonia based on Traditional Chinese Medicine syndrome differentiation显示文摘OBJECTIVE:To evaluate the efficacy and safety of treatment based on syndrome differentiation ofTraditional Chinese Medicine(TCM) for community-acquired pneumonia(CAP).METHODS:A total of 240 CAP patients were randomly divided into the following two groups:thecontrol group was treated by anti-infection plus conventional medicine treatment;and the trial group was treated by TCM plus the above-mentioned treatment given to the controls.The course of treatment was 14 days,and the patients were followed up for 7 days.RESULTS:Of the 240 patients,235 accomplished the whole process of treatment.The five patients who withdrew from the study were brought into an intent-to-treat analysis.The therapeutic effects of the trial group were superior to those of the control group(P<0.01).The trial group took less time to become clinically stable,with a higher score in the quality of life(P<0.01).There were no significant differences in mortality rate(P>0.05),white blood cell count(P>0.05),bacterial clearance rate(P>0.05),and adverse reactions between the two integrated groups.CONCLUSION:Treatment based on TCM syndrome differentiation for CAP has the advantages of resulting in less time to achieve a stable clinical condition,improvement of clinical symptoms and quality of life,and is comparatively safe.Jiansheng Li Xueqing Yu Suyun Li Haifeng Wang Yunping Bai Minghang Wang Zikai Sun Wei Zhang Zhaoshan Zhou Xianhua Jia Qingwei Zhou 2012Journal of Traditional Chinese Medicine2012,32,4:11
20Frequency/time hopping sequence sets with optimal partial Hamming correlation properties显示文摘Frequency hopping/time hopping(FH/TH) sequences have found wide applications in various modern FH/TH spread spectrum communications,such as digital cellular mobile communication,short-range wireless communication,personal communication,and multi-user radar,sonar systems.In order to evaluate the goodness of FH/TH sequences design,the periodic Hamming correlation function is used as an important measure.Usually,the length of correlation window is shorter than the period of the chosen FH/TH sequence,so the study of the partial Hamming correlation of FH/TH sequence is particularly important.In this paper,a new class of FH/TH sequence sets with good partial Hamming correlation properties is proposed and investigated.The construction of new FH/TH sequence sets is based upon the generalized m-sequence and generalized Gordon-Mills-Welch sequence over a polynomial residue class ring.It is shown that new FH/TH sequence sets are optimal with respect to the partial Hamming correlation bound.NIU XianHua PENG DaiYuan ZHOU ZhengChun 2012Science China(Information Sciences)2012,55,10:10
返回顶部 每页显示:
共21页 首页 上一页 第1页 下一页 末页 /21 跳转

网站首页 | 关于我们 | 联系我们 | 产品服务 | 客服中心 | 广告服务 | 版权声明 | 网站联盟 | 友情链接 | 售卡网点

版权所有© 渝B2-20050021-1 渝公网安备 50019002500403号 违法和不良信息举报中心

互联网出版许可证 新出网证(渝)字10号 全国400电话 - 免长途话费