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Round Top Mountain rhyolite(Texas, USA), a massive, unique Y-bearing-fluorite-hosted heavy rare earth element(HREE) deposit

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Journal of Rare Earths 2014年第1期32卷 90-96页

作者： PINgITORE nicholas CLAgUE Juan gORSKI Daniel Department of geological Sciences The University of Texas at El Paso Texas Rare Earth Resources

Round Top Mountain in Hudspeth County, west Texas, USA is a surface-exposed rhyolite intrusion enriched in Y and heavy rare earth elements （HREEs）, as well as Nb, Ta, Be, Li, F, Sn, Rb, Th, and U. The massive tonnage, estimated at well over 1 billion tons, of the deposit makes it a target for recovery of valuable yttrium and HREEs （YHREEs）, and possibly other scarce ele-ments. Because of the extremely fine grain size of the mineralized rhyolite matrix, it has not been clear which minerals host the YHREEs and in what proportions. REE-bearing minerals reported in the deposit included bastn？site-Ce, Y-bearing fluorite, xeno-time-Y, zircon, aeschynite-Ce, a Ca-Th-Pb fluoride, and possibly ancylite-La and cerianite-Ce. Extended X-ray absorption fine struc-ture （EXAFS） indicated that virtually all of the yttrium, a proxy for the HREEs, resided in a coordination in the fluorite-type crystal structure, rather than those in the structures of bastn？site-Ce and xenotime-Y. The YREE grade of the Round Top deposit was just over 0.05%, with 72%of this consisting of YHREEs. This grade was in the range of the South China ionic clay deposits that supply essentially all of the world’s YHREEs. Because the host Y-bearing fluorite is soluble in dilute sulfuric acid at room temperature, a heap leaching of the deposit appeared feasible, aided by the fact that 90%-95%of the rock consists of unreactive and insoluble feld-spars and quartz. The absence of overburden, remarkable consistency of mineralization grade throughout the massive rhyolite, prox-imity （a few km） to a US interstate highway, major rail systems and gas and electricity, temperate climate, and stable political location in the world’s largest economy all enhanced the potential economic appeal of Round Top.

关键词： heavy rare earth elements yttrium-beating fluorite yttrofluorite heap leaching rhyolite Round Top deposit

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Influence of random heterogeneity of shear wave velocity on sliding mass response and seismic deformations of earth slopes

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Earthquake Engineering and Engineering Vibration 2020年第2期19卷 269-287页

作者： Pourya Kazemi Esfeh Bahram Nadi nicholas Fantuzzi Department of Civil ChemicalEnvironmentaland Materials EngineeringUniversity of BolognaItaly Department of Civil Engineering Azad University of NajafabadIran

Soil shear wave velocity has been recognized as a governing parameter in the assessment of the seismic response of *** spatial variability of soil shear wave velocity can influence the seismic response of sliding mass and seismic ***,most analyses of sliding mass response have been carried out by deterministic *** paper stochastically investigates the effect of random heterogeneity of shear wave velocity of soil on the dynamic response of sliding mass using the correlation matrix decomposition method and Monte Carlo simulation(MCS).The software FLAC 7.0 along with a Matlab code has been utilized for this *** influence of statistical parameters on the seismic response of sliding mass and seismic displacements in earth slopes with different inclinations and stiffnesses subject to various earthquake shakings was *** results indicated that,in general,the random heterogeneity of soil shear modulus can have a notable impact on the sliding mass response and that neglecting this phenomenon could lead to underestimation of sliding deformations.

关键词： random heterogeneity random fields Monte Carlo simulation sliding mass response seismic deformations

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Arbuscular mycorrhizal fungi are necessary for the induced response to herbivores by Cucumis sativus

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Journal of Plant Ecology 2013年第2期6卷 171-176页

作者： nicholas A.Barber Department of Biological Sciences Northern Illinois UniversityDeKalbIL 60115USA

Aims Although ecological interactions are often conceptualized and stud-ied in a pairwise framework,ecologists recognize that the outcomes of these interactions are influenced by other members of the ***(i)between plants and insect herbivores and(I)between plants and mycorrhizal fungi are ubiquitous in terrestrial ecosystems and may be linked via common host *** studies suggest that colonization by arbuscular mycorrhizal fungi(AMF)can modifty plants'induced responses to herbivore attack,but these indirect effects of fungal symbionts are poorly understood.I investigated the role of AMF in induced plant response to a gen-eralist ***|manipulated AMF status and herbivory in Cucumis sativus L.(cucumber,Cucurbitaceae)in a greenhouse to investigate induced responses in the presence and absence of the mycorrhi-zal fungus glomus intraradices(glomeraceae).Spodoptera exigua Habner(Noctuidae)were used to manipulate prior damage and later as assay caterpillars.I also measured *** and her-bivory effects on plant N and effects on plant *** tant Findings AMF status affected the induced response of ***,underscor-ing the importance of incorporating the roles of plant symbionts into plant defense *** caterpillars ate significantly more leaf tissue only on mycorrhizal plants that had experienced prior *** more consumption,biomass change in these cat-erpillars did not differ from those feeding on plants with other treat-ment *** N content was reduced by *** but unaffected by herbivory treatments,suggesting that the observed differences in assay caterpillar feeding were due to changes in defensive chemistry that depended on AMF.

关键词： aboveground-belowground cucurbitacin induced defense mutualist resistance trait-mediated indirect effect

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Future of robotics in vascular surgery

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Chinese Medical Journal 2013年第3期126卷 550-553页

作者： Celia Riga nicholas Cheshire Vascular Surgery Department Imperial College St Marys Campus London United Kingdom

For over a decade, there has been a paradigm shift to an endovascular, minimally invasive approach whilst treating diseases of the aorta and its branches, with clear advantages in terms of morbidity and mortality in certain vascular beds, especially in patients with multiple co-morbidities that would otherwise be deemed unsuitable for traditional open surgical approaches. Endovascular intervention however, has certain momhological and anatomical constraints.

关键词： robotic vascular surgery endovascular

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Homocysteine induces expressions of adhesive molecules on leukocytes in whole blood

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Chinese Medical Journal 2001年第12期114卷 3-7,100页

作者：郭雪微 Dudman nicholas Peter 甘肃省人民医院心血管疾病中心兰州730000 澳大利亚新南威尔士大学血栓与血管生物研究中心

Objective To observe whether homocysteine can directly alter the expressions of CD11b, CD18, CD14 and Lselectin on neutrophils, monocytes, and lymphocytes in whole blood from healthy human subjectsMethods Leukocyte surface adhesive molecule expressions were analyzed by immunofluorescence flow cytometry Results Homocysteine at the lowest concentration (20μmol/L) significantly increased surface adhesive molecule expressions of CD11b and CD18 on each cell type and CD14 on monocytes and neutrophils in whole blood These effects were increased at homocysteine concentrations of 200 and 400μmol/L, but at concentrations 1mmol/L, CD11b/CD18 and CD14 expressions on all types of leukocytes were decreased Lselectin expression was slightly decreased on all cell types in whole blood by homocysteineConclusion Homocysteine alters leukocyte expressions of CD11b/CD18, CD14 and Lselectin on leukocytes, which may be involved into homocysteineinduced leukocyte adhesion and migration

关键词： homocysteine · adhesive molecules · leukocytes

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Presentation of hepatocellular antigens

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Cellular & Molecular Immunology 2016年第3期13卷 293-300页

作者： Arash grakoui Ian nicholas Crispe Division of Infectious Diseases Department of Medicine Emory University School of Medicine and Yerkes National Primate Research Center Atlantal GAUSA Department of Pathology University of Washington Seattle WA USA.

The liver is an organ in which antigen-specific T-cell responses manifest a bias toward immune tolerance. This is clearly seen in the rejection of allogeneic liver transplants, and multiple other phenomena suggest that this effect is more general. These include tolerance toward antigens introduced via the portal vein, immune failure to several hepatotropic viruses, the lack of natural liverstage immunity to malaria parasites, and the frequent metastasis of cancers to the liver. Here we review the mechanisms by which T cells engage with hepatocellular antigens, the context in which such encounters occur, and the mechanisms that act to suppress a full T-cell response. While many mechanisms play a role, we will argue that two important processes are the constraints on the cross-presentation of hepatocellular antigens, and the induction of negative feedback inhibition driven by interferons. The constant exposure of the liver to microbial products from the intestine may drive innate immunity, rendering the local environment unfavorable for specific T-cell responses through this mechanism. Nevertheless, tolerance toward hepatocellular antigens is not monolithic and under specific circumstances allows both effective immunity and immunopathology.

关键词： liver hepatocytes immunity tolerance

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Articulating China's Science and Technology:Knowledge Collaboration Networks Within and Beyond the Yangtze River Delta Megalopolis in China

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Chinese geographical Science 2018年第2期28卷 247-260页

作者： LI Yingcheng nicholas A.PHELPS School of Architecture Southeast University Bartlett School of Planning University College London

In this paper, we reconsider the defining but often overlooked ‘hinge' function of megalopolises by analyzing how megalopolises have articulated national and international urban systems in the context of a globalizing knowledge economy. Taking the case of China's Yangtze River Delta(YRD) region, we particularly focus on knowledge circulation within and beyond the YRD region by analyzing the pattern and process of knowledge collaboration at different geographical scales during the 2004–2014 period. Results show that the structure of scientific knowledge collaboration as reflected by co-publications has been strongest at the national scale whereas that of technological knowledge collaboration as measured by co-patents has been strongest at the global scale. Despite this difference, the structure of both scientific and technological knowledge collaboration has been functionally polycentric at the megalopolitan scale but become less so at the national and global scales. The ‘globally connected but locally disconnected' pattern of Shanghai's external knowledge collaboration suggests that the gateway role of the YRD megalopolis in promoting knowledge collaboration at different geographical scales will take time before it is fully realized.

关键词： urban network publication patent scale gateway Yangtze River Delta (YRD)

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Heart healthy equals prostate healthy and statins, aspirin, and/or metformin （S.A.M.） are the ideal recommendations for prostate cancer prevention

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Asian Journal of Andrology 2015年第5期17卷 783-791,I0008页

作者： Mark A Moyad nicholas J Vogelzang Department of Urology University of Michigan Medical Center Ann Arbor Michigan USA Developmental Therapeutics Committee and genitourinary Committee for US Oncology Research Comprehensive Cancer Centers of Nevada Las Vegas Nevada USA

Cardiovascular disease （CVD） has been the number one cause of death in the U.S. for 114 of the last 115 years. Lifestyle factors that promote CVD also appear to increase prostate cancer risk and those that reduce CVD risk also appear to reduce the risk of prostate cancer. The largest randomized trials utilizing dietary supplements or pharmacologic agents for prostate cancer prevention （Selenium and Vitamin E Cancer Prevention Trial [SELECT]） have also shed light on the problems and future solutions in this area. Dietary supplements that have not been found to be CVD protective, such as selenium and Vitamin E have not been found to be prostate protective. In addition, over exposure to specific anti-oxidants in nutritionally replete populations may be encouraging cancer growth. Futuretrials of dietary supplements to prevent prostate cancer could be problematic because by the time a definitive trial is initiated the participants will no longer be ＂deficient＂ in the nutrient being tested, which arguably occurred in the SELECT trial. It is also interesting that statins, aspirin, and/or metformin （S.A.M.） are 3 generic, low-cost, heart healthy agents derived from natural sources with separate mechanism of actions, which all appear to have the best benefit to risk ratio compared to any other agent available for prostate cancer prevention, especially aggressive disease, or as an ancillary agent （s） to conventional cancer treatment. It is time to focus on the forest over the trees and recommend proven CVD protective measures for men concerned about their risk of prostate cancer.

关键词： aspirin diet lifestyle metformin prostate cancer statins

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Animal personalities and their implications for complex signaling

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Current Zoology 2014年第3期60卷 381-386页

作者： nicholas DIRIENZO Ann V HEDRICK Department of Neurobiology Physiology & Behavior Animal Behavior Graduate Group University of California Davis CA 95616 USA Department of Neurobiology Physiology & Behavior University of California Davis CA 95616 USA

Animal personalities have been a major focus of behavioral ecology over the past decade. Consistent individual dif ferences in behavior have been found across taxa, and have been shown to influence a range of ecological processes. The role of personalities in sexual selection has been considered, and examples exist that show selection for personality traits with both assortative and disassortative mating patterns between personality types. One overlooked aspect of the personality and sexual se lection literature is the potential for personalitysignaling interactions, specifically with complex signaling. Complex signaling is a diverse topic in itself, and in short, consists of multiple signals within one or more modalities that interact to elicit a receiver response. Research into complex signaling has been thorough, although at times studies discover complex signaling systems that fail to fit into one of the existing hypotheses in the literature. Here, we argue that personalities may interact with complex signal ing, which should be considered by researchers of both personality and sexual selection and communication. We describe several ways in which personalitycomplex signaling interactions could affect both the signaler and receiver, and the way in which they may drive personalityspecific signals as well as receiver preferences. Finally, we discuss how considering personality in com plex signaling studies may inform theory as well as improve the ability of researchers to accurately describe its function.

关键词： Animal Personalities Sexual Selection Complex Signaling Multimodal Communication Communication

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Teleseismic waves reveal anisotropic poroelastic response of wastewater disposal reservoir

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Earth and Planetary Physics 2021年第6期5卷 547-558页

作者： Andrew J Barbour nicholas M Beeler u.s.geological survey earthquake science centerusa

Connecting earthquake nucleation in basement rock to fluid injection in basal,sedimentary reservoirs,depends heavily on choices related to the poroelastic properties of the fluid-rock system,thermo-chemical effects *** constraints on these parameters outside of laboratory settings are rare,and it is commonly assumed that the rock layers are *** the Arbuckle wastewater disposal reservoir in Osage County,Oklahoma,high-frequency formation pressure changes and collocated broadband ground velocities measured during the passing of large teleseismic waves show a poroelastic response of the reservoir that is both azimuthally variable and anisotropic;this includes evidence of static shifts in pressure that presumably relate to changes in local *** azimuthal dependence in both the static response and shear coupling appears related to tectonic stress and strain indicators such as the orientations of the maximum horizontal stress and faults and *** dynamic strains from a nearby borehole strainmeter,we show that the ratio of shear to volumetric strain coupling is~0.41 which implies a mean Skempton's coefficient of A=0.24 over the plausible range of the undrained Poisson's *** these observations are made at relatively low confining pressure and differential stress,we suggest that the hydraulically conductive fracture network is a primary control on the coupling between pore pressure diffusion and elastic stresses in response to natural or anthropogenic sources.

关键词： poroelasticity dynamic strain anisotropy wastewater disposal Oklahoma induced seismicity

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