检索结果-南通市图书馆

Diffusion of Sm-Nd in Scheelite and its Significance to Isotopic Dating and Tracing

Acta Geologica Sinica(English Edition) 2023年第2期97卷 651-661页

作者： ZHANG Dongliang ian mCOULSON PENG Jiantang LI Shijie WANG Guoqiang Key Laboratory of metallogenic Prediction of Nonferrous metals Ministry of EducationSchool of Geosciences and InfophysicsCentral South UniversityChangsha 410083China Solid Earth Studies Laboratory Department of GeologyUniversity of ReginaReginaSaskatchewan S4S OA2Canada Lunar and Planetary Science Research Center Institute of GeochemistryChinese Academy of SciencesGuiyang 550081China Xi'an Center of Geological Survey CGSXi'an 710054China

As the principal ore mineral in various tungsten(-gold)deposits,scheelite(CaWO_(4))plays an important role in directly dating the timing of ore formation,and in tracing associated material sources through the study of its Sm-Nd geochronology and Nd isotopic *** the retention of Sm-Nd systematics within scheelite is presently unconstrained,equivocal interpretations for isotopic data resulting from this method have occurred quite often in previous studies that apply these isotopic *** order to better elucidate the closure of Sm-Nd in scheelite,the kinetics of Sm and Nd within this mineral lattice were investigated through calculation of diffusion constants presented *** following Arrhenius relations were obtained:D_(Nd)=4.00exp(-438 kJ·mol^(–1)/RT)cm^(2)/s D_(Sm)=1.85exp(-427 kJ·mol^(–1)/RT)cm^(2)/s showing diffusion rate of Nd is near identical to Sm in scheelite when at the same ***,compared to other rare earth elements(REEs),which have markedly different atomic radii to either Nd or Sm,these are shown to exhibit a great variation in *** observed trends in our data are in excellent agreement with the diffusion characteristics of REEs in other tetragonal ABO4 minerals,indicating that ionic radius is a key constraint to the diffusivity of REEs in the various crystal *** this in mind,the same substitution mechanism and a very slight discrepancy in radii will allow us to infer that significant Sm/Nd diffusional fractionation in scheelite is unlikely to occur during most geological *** upon the diffusion data determined herein,Sm and Nd closure temperatures and retention times in scheelite are discussed in terms of diffusion *** results suggest that closure temperatures for Sm-Nd within this mineral are relatively high in contrast to the temperature ranges of ore-formation responsible for scheelite-related deposits,and any later thermal *** is likely,therefore,that rel

关键词： Sm-Nd system diffusion scheelite closure temperature isotopic dating

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Effects of symmetric and asymmetric salt conditions on a selective solid-state nanopore assay

引用

Nano Research 2022年第11期15卷 9936-9942页

作者： ian D.Wadsworth Adam R.Hall Virginia Tech-Wake Forest University School of Biomedical Engineering and Sciences Wake Forest School of MedicineWinston-SalemNC 27101USA Comprehensive Cancer Center Wake Forest School of MedicineWinston-SalemNC 27157USA

Conventional solid-state nanopore measurements sense all translocating entities,necessitating meticulous analysis to differentiate target *** address this,we have established a selective assay with the platform that has shown utility in quantifying several nucleic acid ***,limited detection efficiency and intrinsic noise have so far limited assay resolution to 10 *** in this value require manipulation of translocation ***,we report the effects of NaCl conditions on assay *** first investigate symmetric conditions,finding sensitivity increases with salt concentration but selectivity is maximized at 1.0 m *** then probe asymmetric conditions,showing a remarkable impact on assay sensitivity and selectivity when measurement buffer NaCl concentration in the reservoir with the translocating molecules is low and the opposite reservoir is *** optimum conditions,we demonstrate detection of target biomolecules down to a concentration of 100 pm which is an improvement of 2 orders of magnitude over past results.

关键词： solid-state nanopores biomarkers amplification-free detection salt gradient nucleic acids

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Stevens-Johnson syndrome complicating adalimumab therapy in Crohn's disease

引用

World Journal of Gastroenterology 2009年第35期15卷 4449-4452页

作者： muna Salama ian Craig Lawrance Department of Gastroenterology Fremantle HospitalFremantle 6059WAAustralia Department of Gastroenterology Fremantle HospitalWAAustralia Centre for Inflammatory Bowel Diseases Fremantle HospitalWA Australia Department of medicine and Pharmacology University of Western AustraliaFremantle HospitalFremantle 6059WA Australia

The anti-tumor necrosis factor(TNF)αmedications demonstrate efficacy in the induction of remission and its maintenance in numerous chronic inflammatory *** the increasing number of patients receiving anti-TNFαagents,however,less common adverse reactions will *** eruptions complicating treatment with an anti-TNFαagent are not uncommon,occurring in around 20%of patients. Adalimumab,a fully humanized antibody against TNFα, may be expected to cause minimal immune-mediated skin reactions compared to the chimeric monoclonal antibody,***,however,report a case of Stevens-Johnson syndrome that required hospitalization and cessation of adalimumab in a patient with Crohn’ s disease(CD).In this case report,a 29-year-old male with colonic and perianal CD with associated erythema nodosum and large joint arthropathy developed severe mucositis,peripheral rash and desquamation,fevers and respiratory symptoms concomitant with a second dose of 40 mg adalimumab after a 2 mo break from adalimumab *** biopsies of the abdominal wall confirmed erythema multiforme and the patient was on no other drugs and infective etiologies were *** patient responded rapidly to IV hydrocortisone and was able to be commenced on infliximab without recurrence of the Stevens-Johnson *** skin reactions have now been described in three of the TNFαantagonists(infliximab,etanercept and adalimumab).These reactions can be serious and prescribers need to be aware of the potential mucocutaneous side effects of these agents,especially as Stevens-Johnson syndrome is associated with significant morbidity and mortality.

关键词： Stevens-Johnson syndrome Crohn'sdisease Adalimumab Serious adverse effect

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Etiopathogenesis of primary biliary cirrhosis

引用

World Journal of Gastroenterology 2008年第21期14卷 3328-3337页

作者： Ana Lleo Pietro Invernizzi ian R mackay Harry Prince Ren-Qian Zhong m Eric Gershwin Division of Internal medicine and Liver Unit San Paolo Hospital School of Medicine University of Milan Milan 20142 Italy Division of Rheumatology Allergy and Clinical Immunology University of California at Davis Davis CA 95616 United States Department of Biochemistry & molecular Biology Monash University Clayton Victoria 3800 Australia Focus Diagnostics 5785 Corporate Avenue Cypress CA 90630 United States Laboratory Diagnostics of Changzheng Hospital Second Military Medical University and Clinical Immunology Center of PLA Shanghai 200003 China

Primary biliary cirrhosis(PBC) is an autoimmune disease of the liver characterized by progressive bile duct destruction eventually leading to cirrhosis and liver *** serological hallmark of the disease is the presence of circulating antimitochondrial antibodies(AmA).These reflect the presence of autoreactive T and B cells to the culprit antigens,the E2 subunits of mitochondrial 2-oxo-acid dehydrogenase enzymes,chiefly pyruvate dehydrogenase(PDC-E2).The disease results from a combination of genetic and environmental risk *** predisposition is indicated by the higher familial incidence of the disease particularly among siblings and the high concordance rate among monozygotic *** triggering events appear crucial to disrupt a pre-existing unstable immune tolerance of genetic origin allowing,after a long latency,the emergence of clinical *** mimetopes of the vulnerable epitope of the PDC-E2 autoantigen can be derived from microbes that utilize the PDC enzyme or,alternatively,environmental xenobiotics/chemical compounds that modify the structure of native proteins to make them immunogenic.A further alternative as a source of antigen is PDC-E2 derived from apoptotic *** the effector phase the biliary ductular cell,by reason of itsproclivity to express the antigen PDC-E2 in the course of apoptosis,undergoes a multilineage immune attack comprised of CD4+ and CD8+ T cells and *** this article,we critically review the available evidence on etiopathogenesis of PBC and present interpretations of complex data,new developments and theories,and nominate directions for future research.

关键词： Autoantibodies Autoreactive T cells 2-oxoacid dehydrogenase Biliary epithelial cells Primary biliary cirrhosis

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Detrital zircon U-Pb-He double dating: A method of quantifying long- and short-term exhumation rates in collisional orogens

引用

Science China Earth Sciences 2014年第11期57卷 2702-2711页

作者： Christina Yan WANG ian H.CAmPBELL Peter W.REINERS Charlotte m.ALLEN Key Laboratory of mineralogy and metallogeny Guangzhou Institute of Geochemistry Chinese Academy of Sciences Research School of Earth Sciences The Australian National UniversityCanberra ACT 0200 Australia Department of Geosciences University of ArizonaTucson AZ 85721 USA

A U-Pb-He double-dating method is applied to detrital zircons with core-rim structure from the Ganges River in order to de- termine average short and long-term exhumation rates for the Himalayas. Long-term rates are calculated from the U/Pb ages of metamorphic rims of the grains that formed during the Himalayan orogeny and their crystallization temperatures, which are calculated from the Ti-in-zircon thermometer. Short-term rates are calculated from （U-Th）/He ages of the grains with appro- priate closure temperatures. The results show that short-term rates for the Himalayas, which range from 0.70 ± 0.09 to 2.67 ± 0.40 km/myr and average 1.75 ± 0.59 （1δ） km/myr, are higher and more varied than the long-term rates, which range from 0.84 ±0.16 to 1.85 ± 0.35 km/myr and average 1.26 ±0.25 （let） km/myr. The differences between the long-term and short-term rates can be attributed to continuous exhumation of the host rocks in different mechanisms in continental collision orogen. The U/Pb ages of 44.0 ± 3.7 to 18.3 ±0.5 ma for the zircon rims indicate a protracted episode of -：25 myr for regional metamorphism of the host rocks at deeper crust, whereas the （U-Th）/He ages of 42.2 ± 1.8 to 1.3 ± 0.2 ma for the zircon grains represent a protracted period of -40 myr for exposure of the host rocks to shallower crustal level. In particular, the oldest （U-Th）/He ages of the zircon grains are close to the oldest U/Pb ages for the rims, indicating that some parcels of the rocks that contain zircons were rapidly exhumed from deep to shallow levels in the stage of collisional orogeny. On the other hand, some parcels of the rocks may have been carried upwards by thrust faults in the post-collisional stage. The parcels could be carried upwards by the thrust faults that steepen as they near the surface, or by transient movement faults so that areas of rapid exhu- mation became areas of slow exhumation and visa versa on a time scale of a few myr in order to maintain the continuous ex- huma

关键词： zircon U-Pb-He double-dating method Himalayas exhumation rate collisional orogen

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Zircon U–Pb dating,geochemical,and Sr–Nd–Pb–Hf isotopic constraints on the age and origin of intermediate to felsic igneous rocks at South Altyn,Xinjiang,China

引用

Acta Geochimica 2020年第5期39卷 698-716页

作者： Shen Liu Caixia Feng Yan Fan Xiaoqing Chen Yuhong Yang Huibo Zhao ian m.Coulson State Key Laboratory of Continental Dynamics and Department of Geology Northwest University229 Taibai RoadXi'an 710069China College of Earth Sciences Jilin University2199 Jianshe RoadChangchun 130061China Solid Earth Studies Laboratory Department of GeologyUniversity of ReginaReginaSK S4S 0A2Canada

As a part of a giant trending fault system in the Asian continent and one where a strong zone of left strikeslip fault is present,the Altyn Orogenic belt(AOB)has become an important focus for *** rocks are widely distributed across the ***,many investigations have focused primarily on Paleozoic igneous rocks;discussion of mesozoic related igneous activity is often *** we present the result of studies of representative diorite and granite rocks outcropping in the AOB,within the Xinjiang Uygur Autonomous Region,South Altyn,*** present new zircon LA-ICP-mS U-Pb age,geochemical,and Sr-Nd-Pb-Hf isotopic data for these sample suites,identifying them as typical igneous rocks formed between 238±1.5 and 238.8±1.1 *** rocks that we studied fall into the alkaline series,also enriched in light rare earth elements(LREE),some large ion lithophile elements(LILE;e.g.,Rb,Ba,Sr,and K),Pb,Th and U,and depleted in heavy rare earth elements(HREE),Nb,Ta,Hf,and *** granite and diorite have high initial 87Sr/86Sr ratios(0.7062-0.7114),negativeεNd(t)values(-8.8 to-11.3),εHf(t)values(-8.7 to-18.7),and relatively constant Pb isotopic ratios((206-Pb/204Pb)i=6.74-17.884,(207Pb/204Pb)i=15.51-15.58,and(208Pb/204Pb)i=35.36-38.04),*** suggests that the magmas parental to these rocks were generated from the partial melting of the ancient *** parental magmas to these rocks experienced a degree of fractionation of plagioclase,K-feldspar,and hornblende,possibly during rapid magma *** on these studies,we propose a reasonable model for the origin of the investigated rocks from the Xinjiang Uygur Autonomous Region of South Altyn,which involves crustal thickening,lithospheric extension,and asthenosphere upwelling,that induced crustal melting.

关键词： Altyn orogenic belt Zircon U–Pb dating Geochemistry,Sr–Nd–Pb–Hf isotope Origin

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

微粒对多晶冰流变行为的影响——(Ⅱ)滞弹性行为

引用

地球物理学报 2007年第4期50卷 1156-1160页

作者：宋旼 David m Cole ian Baker 中南大学粉末冶金国家重点实验室 US Army Cold Regions Research and Engineering Laboratory HanoverNH03755USA Thayer School of Engineering Dartmouth CollegeHanoverNH03755USA

用反相直接加载的方法研究了微粒对多晶冰滞弹性的影响.结果表明:在较高频率时(1Hz和10-1Hz),滞弹性应变与应力峰值呈线性关系;在较低频率时(10-2Hz),其应力/应变偏离线性关系.微粒在高频时(1Hz)通过阻碍晶界滑移对晶界弛豫产生重要影响... 详细信息

用反相直接加载的方法研究了微粒对多晶冰滞弹性的影响.结果表明:在较高频率时(1Hz和10-1Hz),滞弹性应变与应力峰值呈线性关系;在较低频率时(10-2Hz),其应力/应变偏离线性关系.微粒在高频时(1Hz)通过阻碍晶界滑移对晶界弛豫产生重要影响,增加了模量和降低了内耗.但微粒对低频时的位错弛豫没有明显的影响.通过滞弹性实验计算了非线性弛豫模型的两个重要参数,计算表明K值约为0.07Pa,α值约为0.54.

关键词：冰与冰川滞弹性弛豫模型流变

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

mapping groundwater dependent ecosystem potential in a semi-arid environment using aremote sensing-based multiple-lines-of-evidence approach

引用

International Journal of Digital Earth 2023年第1期16卷 375-406页

作者： Stephen G.Fildes Tanya m.Doody David Bruce ian F.Clark Okke Batelaan UniSA STEm University of South AustraliaAdelaideAustralia CSIRO Land and WaterAdelaideAustralia National Centre for Groundwater Research and Training(NCGRT) College of Science and EngineeringFlinders UniversityBedford ParkAustralia

Groundwater dependent ecosystems(GDEs)are vulnerable to groundwater regime ***,their protection is often hampered by challenges in their *** is presented a remote sensing-based GDE potential mapping approach based on the persistency of relevant vegetation parameters during prolonged dry periods as an indicator of potential‘consistency’of water supply(***).The study uses a novel approach to characterising persistency for selected vegetation parameters based on a normalised difference measure and an adaptation of the coefficient of variation *** of parameters was facilitated through the analytic hierarchy process providing a structured weighting approach to minimise parameter *** approach is demonstrated in the semi-arid Flinders Ranges of South Australia where new groundwater resources are being sought to support local domestic and industry *** in GDE potential were mapped to better target areas where exploration of groundwater should be *** results indicated a high-level of agreement of 77%with an independent springs dataset,along with an 87%agreement with areas coinciding with known phreatophyte species and depths to *** index-based mapping approach has potential applicability across landscapes,as it normalises for variations in vegetation cover,minimises technical overheads,and employs continental-wide remote sensing data-products.

关键词： coefficient of variation NDVI coefficient of variation fractional cover barest Earth wetness percentiles actual evapotranspiration analytic hierarchy process groundwater potential

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Zinc, copper, and strontium isotopic variability in the Baiyangping Cu–Pb–Zn–Ag polymetallic ore field, Lanping Basin, Southwest China

引用

Acta Geochimica 2021年第4期40卷 557-574页

作者： Caixia Feng Shen Liu Guoxiang Chi Xianwu Bi Ruizhong Hu ian mCoulson State Key Laboratory of Continental Dynamics Department of GeologyNorthwest University229 Taibai RoadXi’an 710069China Departments of Geology University of Regina3737 Wascana ParkwayReginaSK S4S 0A2Canada Institute of Geochemistry Chinese Academy of Sciences99 Lincheng RoadGuiyang 550002China

The Baiyangping Cu-Ag polymetallic ore district is located in the northern part of the Lanping-Simao foreland fold belt,between the Jinshajiang-Ailaoshan and Lancangjiang faults,and the deposit can be divided into eastern and western ore *** upon microscope observation of ore minerals and analysis of zinc,copper,and strontium isotope composition,we conclude that:(1)the zinc isotopic compositions of sphalerite from the eastern and western ore belt of the Baiyangping polymetallic ore deposits are enriched in both the heavy(-0.09‰ to+0.15‰) and light(-0.19‰ to-0.01‰)zinc *** fractionation is likely the additional factor controlling the observed temporal and spatial variations in zinc isotopes in the two studied ore *** zinc isotopic composition in the Baiyangping polymetallic Pb-Zn deposits may have the same fractionation as that of magmatic-hydrothermal,VHmS,SEDEX,and mVT deposits,as demonstrated by geological and other geochemical evidence;(2) the range of δ^(65)Cu in massive tetrahedrite is from-0.06‰ to+0.12 ‰ that relates to the early stages of ore-formation,which are higher than that of venial chalcopyrite(from-0.72‰ to-0.07‰)formed at a late ore-forming stage in the western ore *** ore-forming stages and alteration or leaching processes are likely the main factors controlling the observed variations in copper isotopes in the western ore zone;(3) the ^(87)Sr/^(86)Sr value of hydrothermal calcite in eastern(0.7080-0.7093) and western(0.7085-0.7113) ore belt suggested that mineralization of early calcite,with^(87)Sr/^(86)Sr values much higher than in ancient Late Triassic seawater,may be related to recrystallization from a radiogenic Sr-rich or silicifying fluid,either from the strata that the ore-forming fluid flows through or from other fluids.

关键词： Zn-Cu-Sr isotopic variation Cu-Pb-Zn-Ag poly-metallic ore deposit Baiyangping Lanping Basin

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Geochronology and Genetic model for Early Cretaceous Volcanic Rocks from the Southern Qiangtang Terrane,Northern Tibet,China: Constraints from U-Pb Zircon Dating, Whole-Rock Geochemical and Sr-Nd Isotopic Data

引用

Acta Geologica Sinica(English Edition) 2018年第6期92卷 2157-2178页

作者： LIU Shen FENG Caixia m.Santosh FENG Guangying XU mengjing ian m.COULSON GUO Xiaolei GUO Zhuang FAN Yan State Key Laboratory of Continental Dynamics and Department of Geology Northwest UniversityXi'an 710069China China University of Geosciences Beijing 100083 BeijingChina Department of Earth Sciences University of AdelaideAdelaide SA 5005Australia Institute of Geology Chinese Academy of Geological Sciences100037 BeijingChina Solid Earth Studies Laboratory Department of GeologyUniversity of ReginaReginaSaskatchewan S4S OA2Canada

Post-collisional volcanic rocks of mesozoic age occur in the regions adjacent to Gerze, part of the southern Qiangtang Terrane of northern Tibet, China. Geochronological, geochemical, and wholerock Sr-Nd isotopic analyses were performed on the volcanic rocks to better characterize their emplacement age and models for their origin. Laser ablation-inductively coupled plasma-mass spectrometry(LA-ICP-mS) U-Pb zircon analyses yielded consistent ages ranging from 123.1±0.94 ma to 124.5±0.89 ma for six volcanic rocks from the study area. The intermediate volcanic rocks belong to the alkaline and sub-alkaline magma series in terms of K2 O+Na2 O contents(5.9%–9.0%), and to the shoshonitic and calc-alkaline series on the basis of their high K2 O contents(1.4%–3.3%). The Gerze volcanic rocks are characterized by the enrichment of light rare earth elements [(La/Yb)N=34.9–49.5] and large–ion lithophile elements(e.g., Rb, Ba, Th, U, K, Pb, and Sr), slightly negative Eu anomalies(Eu/Eu*=0.19–0.24), and negative anomalies in high field strength elements(e.g., Nb, Ta, Hf and Ti), relative to primitive mantle. The samples show slightly elevated(87 Sr/86 Sr)i values that range from 0.7049 to 0.7057, and low εNd(t) values from-0.89 to-2.89. These results suggest that the volcanic rocks studied derived from a compositionally heterogeneous mantle source and that their parent magmas were basaltic. The more mafic, parental magmas to the Gerze volcanic rocks likely underwent fractional crystallization of clinopyroxene, hornblende, biotite, and potassium feldspar, during ascent, with little to no crustal contamination, prior to their eruption/emplacement. While these volcanic rocks exhibit geochemical signatures typical of magmas formed in a destructive plate-margin setting, it is plausible that their mantle source might also have acquired such characteristics in an earlier episode of subduction.

关键词： volcanic rock U–Pb age–dating origin Qiangtang Terrane northern Tibet

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：