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Astronomical time scale for the lower Doushantuo Formation of early Ediacaran,South China

Science bulletin 2018年第22期63卷 1485-1494页

作者： Yu Sui Chunju Huang Rui Zhang Zhixiang Wang james Ogg David b.Kemp State Key Laboratory of biogeology and Environmental Geology School of Earth SciencesChina University of GeosciencesWuhan 430074China State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation Chengdu University of TechnologyChengdu 610059China Department of Earth Atmospheric and Planetary SciencesPurdue UniversityWest LafayetteIN 47907USA School of Geosciences University of AberdeenAberdeenScotland AB243UEUK

Nearly 90% of the Ediacaran Period(635–541 Ma) of the Neoproterozoic is represented by the Doushantuo Formation(DST Fm) in South *** lowest Member I is a 3.7 m-thick cap carbonate deposited at the termination of the Cryogenian Marinoan *** DST Fm consists of alternating organic-rich black shale and thinly bedded dolostone, and it contains some of the oldest records of multicellular life and three pronounced negative carbon isotope *** Jiulongwan(JLW) section is a well-studied reference section for these Ediacaran *** analysis of geochemical data through the lower DST Fm(22.3 m) shows 27 predominant ～90 cm sedimentary cycles that correspond to 405-ka long eccentricity *** power spectra of the 405-ka tuned Ca and Fe/Ti series show significant peaks at ～1.2-Ma, 405-ka, 133-ka, 128-ka, 100-ka, 82-ka, ～31-ka and 29-ka periods, respectively.A 11.16 Malong astronomical time scale has been constructed for the lower DST Fm and provide a duration of 1.6 Ma for the cap carbonate(Member Ⅰ) based on the 405-ka long eccentricity cycle *** the U-Pb age of 635.2 ± 0.6 Ma for the volcanic ash bed at the Member Ⅰ/Ⅱboundary, we proposed a 636.8 Ma age for the base of the DST *** ages and astronomical timescale provide important new constraints on the subdivision of Ediacaran strata, and have implications for understanding the character of the first negative δ^(13)C excursion(EN1).Orbital forcing may have been played an important role for the climate changes and the evolution of Ediacaran multi-cellular life and the carbon cycle variations.

关键词： Ediacaran Doushantuo Formation Astronomical time scale Orbital forcing Jiulongwan section

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Time-dependent viscoelastic properties along rat small intestine

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World Journal of Gastroenterology 2005年第32期11卷 4974-4978页

作者： james b Smith Jing-bo Zhao Yan-Ling Dou Hans Gregersen Institute of Experimental Clinical Research Aarhus University Denmark Center of Excellence in Visceral biomechanics and Pain Aalborg Hospital and Center of SMI Aalborg University Aalborg Denmark Department of Gastroenterology China-Japan Friendship Hospital Beijing 100029 China

AIM： To measure the time-dependent （viscoelastic） behavior in the change of the small intestinal opening angle and to test how well the behavior could be described by the Kelvin model for a standard linear solid. METHODS： Segments from the duodenum, jejunum, and ileum were harvested from 10 female Wistar rats and the luminal diameter, wall thickness, and opening angle over time （θ（t）） were measured from rings cut from these segments. RESULTS： Morphometric variations were found along the small intestine with an increase in luminal area and a decrease in wall thickness from the duodenum to the ileum. The opening angle obtained after 60 rain was highest in the duodenum （220.8±12.9°）and decreased along the length of the intestine to 143.9±8.9° in the jejunum and 151.4±9.4° in the ileum. The change of opening angle as a function of time, fitted well to the Kelvin model using the equation θ（t）/θo = [1-ηexp （-λt）] after the ring was cut. The computed creep rate λ. did not differ between the segments. Compared to constant calculated from pig aorta and coronary artery, it showed that α agreed well （within 5%）, η was three times larger than that for vascular tissue, and λ ranged ±40% from the value of the pig coronary artery and was a third of the value of pig aorta. CONCLUSION： The change of opening angle over time for all the small intestine segments fits well to the standard linear spring-dashpot model. This viscoelastic constant of the rat small intestine is fairly homogenous along its length. The data obtained from this study add to a base set of biomechanical data on the small intestine and provide a reference state for comparison to other tissues,diseased intestinal tissue or intestinal tissue exposed to drugs or chemicals.

关键词： biomechanics Standard linear solid Creep Opening angle

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More than Target 6.3： A Systems Approach to Rethinking Sustainable Development Goals in a Resource-Scarce World

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Engineering 2016年第4期2卷 481-489页

作者： Qiong Zhang Christine Prouty Julie b. Zimmerman james R. Mihelcic University of South Florida Tampa EL 33620 USA Yale University New Haven CT06520 USA

The 2030 Agenda for Sustainable Development outlines 17 individual Sustainable Development Goals （SDGs） that guide the needs of practice for many professional disciplines around the world, including engineering, research, policy, and development. The SDGs represent commitments to reduce poverty, hunger, ill health, gender inequality, environmental degradation, and lack of access to clean water and sanitation. If a typical reductionist approach is employed to address and optimize individual goals, it may lead to a failure in technological, policy, or managerial development interventions through unin- tended consequences in other goals. This study uses a systems approach to understand the fundamental dynamics between the SDGs in order to identify potential synergies and antagonisms. A conceptual system model was constructed to illustrate the causal relationships between SDGs, examine system structures using generic system archetypes, and identify leverage points to effectively influence intentional and minimize unintentional changes in the system. The structure of interactions among the SDGs reflects three archetypes of system behavior： Reinforcing Growth, Limits to Growth, and Growth and Underinvestment. The leverage points identified from the conceptual model are gender equality, sustainable management of water and sanitation, alternative resources, sustainable livelihood standards, and global partnerships. Such a conceptual system analysis of SDGs can enhance the likelihood that the development community will broaden its understanding of the potential synergistic benefits of their projects on resource management, environmental sustainability, and climate change. by linking the interactions and feedbacks of those projects with economic gains, women＇s empowerment, and educational equality, stakeholders can recognize holistic improvements that can be made to the quality of life of many of the world＇s poor.

关键词： Systems thinking SanitationEnvironmental protection GenderResource recovery Causal loop diagram Sustainability

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Geographic and temporal variations of sulfate aerosols over the Pacific Ocean

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Acta Oceanologica Sinica 1991年第1期10卷 47-71页

作者： F.Parungo C.Nagamoto b.Kopcewicz J.harris S.Hoyt Air Resources Laboratory NoAA/ERLBoulderColoradoU.S.A.Air Resources LaboratoryNoAA/ERLBoulderColoradoU.S.A.Air Resources LaboratoryNoAA/ERLBoulderColoradoU.S.A.Air Resources LaboratoryNoAA/ERLBoulderColoradoU.S.A.Environmental Analytical Service Inc. San Luis ObispoCaliforniaU. S. A.

To investigate the life cycle of marine sulfate aerosols, chemicophysical characteristics of marine aerosolswere measured during five cruises in the Pacific Ocean. Dimethyl sulfide concentrations in seawater and in the air were also measured. The geographic variation of sulfate-aerosol concentrations was studied in relation to biogenic and anthropogenic sources,transport with air trajectories, and chemical transformations in the atmosphere. The highest concentrations were found near Asian and American ports, indicating anthropogenic pollution is the major sulfate aerosols source. Higher concentrations were observed in the upwelling regions than in the oligotrophic areas. Along the coastal regions, both mass and number concentrations of sulfate aerosols depended on wind direction and wind speed, and land-breeze and sea-breeze oscillations; no clear diurnal variation was detected. In pelagic areas, along the equator, the concentrations of small sulfate particles showed a maximum in the afternoon and the minimum at night , indicating photo-oxidation as an important process for gas-to-particle conversion. Higher sulfate-aerosol concentrations were observed in spring than in autumn and higher concentrations were found during the La Nina anomaly than during the El Nino anomaly. biogenic source of sulfate aerosols has an important role in the remote ocean. Case studies of sulfate-aerosol distributions are discussed.

关键词： DMS Geographic and temporal variations of sulfate aerosols over the Pacific Ocean over

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MbE growth of tensile-strained Ge quantum wells anC quantum dots

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Frontiers of Optoelectronics 2012年第1期5卷 112-116页

作者： Yijie HUO Hai LIN Robert CHEN Yiwen RONG Theodore I.KAMINS james S.harris Department of Electrical Engineering Stanford UniversityStanfordCalifomia 94305USA Department of Materials Science and Engineering Stanford UniversityStanfordCalifornia 94305USA

Germanium （Ge） has gained much interest due to the potential of becoming a direct band gap material and an efficient light source for the future complementary metal-oxide-semiconductor （CMOS） compatible photonic integrated circuits. In this paper, highly biaxial tensile strained Ge quantum wells （QWs） and quantum dots （QDs） grown by molecular beam epitaxy are presented. Through relaxed step-graded InGaAs buffer layers with a larger lattice constant, up to 2.3% tensile-strained Ge QWs as well as up to 2.46% tensile-strained Ge QDs are obtained. Characterizations show the good material quality as well as low threading dislocation density. A strong increase of photoluminescence （PL） with highly tensile strained Ge layers at low temperature suggests the existence of a direct band gap semiconductor.

关键词： Si photonics germanium (Ge) tensilestrained photoluminescence (PL)

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Silk-based nerve guidance conduits with macroscopic holes modulate the vascularization of regenerating rat sciatic nerve

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Neural Regeneration Research 2025年第6期20卷 1789-1800页

作者： Carina Hromada Patrick Heimel Markus Kerbl LászlóGál Sylvia Nürnberger barbara Schaedl james Ferguson Nicole Swiadek Xavier Monforte Johannes C.Heinzel Antal Nógrádi Andreas H.Teuschl-Woller David Hercher Department Life Science Engineering University of Applied Sciences Technikum WienViennaAustria Austrian Cluster for Tissue Regeneration ViennaAustria Ludwig boltzmann Institute for Traumatology The Research Center in Cooperation with AUVAViennaAustria University Clinic of Dentistry Medical University of ViennaViennaAustria Department of Plastic Reconstructive and Aesthetic SurgeryLandesklinikum Wiener Neustadt2700 Wiener NeustadtAustria Department of Anatomy Histology and EmbryologyAlbert Szent-Györgyi Medical SchoolUniversity of SzegedSzegedHungary Medical University of Vienna Department of Orthopedics and Trauma SurgeryDevision of Trauma SurgeryViennaAustria Department of Hand- PlasticReconstructive and Burn SurgeryBG Unfallklinik TuebingenUniversity of TuebingenTuebingenGermany

Peripheral nerve injuries induce a severe motor and sensory deficit. Since the availability of autologous nerve transplants for nerve repair is very limited, alternative treatment strategies are sought, including the use of tubular nerve guidance conduits(tNGCs). However, the use of tNGCs results in poor functional recovery and central necrosis of the regenerating tissue, which limits their application to short nerve lesion defects(typically shorter than 3 cm). Given the importance of vascularization in nerve regeneration, we hypothesized that enabling the growth of blood vessels from the surrounding tissue into the regenerating nerve within the tNGC would help eliminate necrotic processes and lead to improved regeneration. In this study, we reported the application of macroscopic holes into the tubular walls of silk-based tNGCs and compared the various features of these improved silk^(+) tNGCs with the tubes without holes(silk^(–) tNGCs) and autologous nerve transplants in an 8-mm sciatic nerve defect in rats. Using a combination of micro-computed tomography and histological analyses, we were able to prove that the use of silk^(+) tNGCs induced the growth of blood vessels from the adjacent tissue to the intraluminal neovascular formation. A significantly higher number of blood vessels in the silk^(+) group was found compared with autologous nerve transplants and silk^(–), accompanied by improved axon regeneration at the distal coaptation point compared with the silk^(–) tNGCs at 7 weeks postoperatively. In the 15-mm(critical size) sciatic nerve defect model, we again observed a distinct ingrowth of blood vessels through the tubular walls of silk^(+) tNGCs, but without improved functional recovery at 12 weeks postoperatively. Our data proves that macroporous tNGCs increase the vascular supply of regenerating nerves and facilitate improved axonal regeneration in a short-defect model but not in a critical-size defect model. This study suggests that further optimizatio

关键词： axon regeneration blood vessel functional recovery macroporous nerve lesion peripheral nerve repair sciatic nerve silk-based nerve guidance conduit vascularization

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Simplified heavy metal staining techniques demonstrated with Fast Plant leaf tissue

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Cell Research 1991年第1期 89-96页

作者： harris JOSEPH b..THOMAS G. GUILLIAMS JEFFERY A. SCHULTZ

Fast Plant(brassica rapa,Cruciferae)leaf tissuefixed in glutaraldehyde-acrolein and post-fixed in os-mium,was examined for response to several easily-prepared heavy metal *** and uranium,separately and in combination,gave typical resultsacross the spectrum of cell *** a single stainfollowing osmium,bismuth produced images seeminglyequivalent to lead and *** acidproduced very good membrane delineation but produceda washed-out background image similar to that from *** compounds were especiallyresponsive to ruthenium;the cytoplasm and the matrixof all organelles were also stained very *** were no more demanding than traditionalstaining methods and may be easily used in research *** Plant materials are a reliable,quick andeasy source of living material.

关键词： Fast Plant leaf tissue Simplified heavy metal staining technique.

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Characterization of a novel murine Sost ERT2 Cre model targeting osteocytes

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bone Research 2019年第1期7卷 41-53页

作者： Delphine b.Maurel Tsutomu Matsumoto Julian A.Vallejo Mark L.Johnson Sarah L.Dallas Yukiko Kitase Marco brotto Michael J.Wacker Marie A.harris Stephen E.harris Lynda F.bonewald Department of Oral and Craniofacial Sciences University of Missouri-Kansas City School of DentistryKansas CityMOUSA Department of Anatomy and Cell biology Indiana University School of MedicineIndianapolisINUSA bone.Muscle Collaborative Sciences College of Nursing and Health InnovationUniversity of Texas at ArlingtonArlingtonUSA Department of biomedical Sciences University of Missouri-Kansas City School of MedicineKansas CityMOUSA University of Texas Health Science Center San AntonioTXUSA Department of Orthopaedic Surgery Indiana University School of MedicineIndianapolisINUSA Pharmaceutical Sciences Department Universite de BordeauxBio-TisINSERM Unité1026 BioTis146 Rue Léo Saignat33076 BordeauxFrance

Transgenic mice are widely used to delete or overexpress genes in a cell specific manner to advance knowledge of bone biology,function and *** numerous Cre models exist to target gene recombination in osteoblasts and osteoclasts,few target osteocytes specifically,particularly mature *** goal was to create a spatial and temporal conditional Cre model using tamoxifen to induce Cre activity in mature osteocytes using a bac construct containing the 5’and 3’regions of the Sost gene(Sost ERT2 Cre).Four founder lines were crossed with the Ai9 Cre reporter *** founder line showed high and specific activity in mature *** and organs were imaged and fluorescent signal *** no activity was observed in 2 day old pups,by 2 months of age some osteocytes were positive as osteocyte Cre activity became spontaneous or‘leaky’with *** percentage of positive osteocytes increased following tamoxifen injection,especially in males,with 43%to 95%positive cells compared to 19%to 32%in *** signal was observed in any bone surface cell,bone marrow,nor in muscle with or without tamoxifen *** spontaneous signal was observed in any other ***,with tamoxifen injection,a few positive cells were observed in kidney,eye,lung,heart and *** other organs,28 in total,were negative with tamoxifen ***,with age,a muscle phenotype was apparent in the Sost-ERT2 Cre ***,although this mouse model may be useful for targeting gene deletion or expression to mature osteocytes,the muscle phenotype may restrict the use of this model to specific applications and should be considered when interpreting data.

关键词： cell knowledge model

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从北美的研究看大熊猫的种群动态(英文)

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动物学报 2004年第4期50卷 662-668页

作者： Richard b. harris Wildlife biology Program College of Forestry and Conservation University of Montana Missoula MT USA 59812

尽管人们对大熊猫的种群动态了解很少 ,但是我们可以从对相似物种的研究和经历中了解一些基本原理。在不减少对后续的有关大熊猫种群特征、遗传学和行为研究的前提下 ,根据对北美食肉动物种群生物学的理解 ,我提出了下面一般性的结论。... 详细信息

尽管人们对大熊猫的种群动态了解很少 ,但是我们可以从对相似物种的研究和经历中了解一些基本原理。在不减少对后续的有关大熊猫种群特征、遗传学和行为研究的前提下 ,根据对北美食肉动物种群生物学的理解 ,我提出了下面一般性的结论。首先 ,弹性分析确认 ,大熊猫演变出了确保雌性个体高存活率的生活史。比较而言 ,繁殖率并不重要。成年雌性个体的存活率增加 ,比相应的繁殖输出要导致 5倍的保护效益。第二 ,在可能表现大熊猫种群特征的假设前提下 ,雄性 (甚至成年个体 )的存活率相对而言也是不重要的。第三 ,尽管都认为大熊猫繁殖很缓慢 ,但是从数学上来说 ,如果生境 (以及与其相关的存活率 )允许 ,大熊猫的种群能够比较快地增长。最后 ,北美西部对濒危物种再引入的经验提醒我们 ,保留大片尚未破碎化的生境非常重要。狼在 2 0世纪中叶就在美国西部灭绝了 ,但是目前由于有广阔的生存区域和丰富的食物 ,种群恢复很快。对比而言 ,最近从原野中消失的黑足鼬 ,在种群重建过程中遇到了很大的困难 ,尽管人们在科学上做出了巨大的努力。看来黑足鼬可能只是没有足够的野外栖息地 (猎物 )以维持生存。如果没有足够的栖息地。

关键词：大熊猫种群野外栖息地濒危物种

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基于月球动力学演化的地质年代划分

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中国科学：地球科学 2024年第1期54卷 244-263页

作者：郭弟均刘建忠 james W.HEAD 张福勤凌宗成陈圣波陈建平丁孝忠籍进柱欧阳自远中国科学院国家空间科学中心空间天气学国家重点实验室北京100190 中国科学院地球化学研究所月球与行星科学中心贵阳550081 Department of Earth Environmental and Planetary SciencesBrown UniversityProvidenceRI 02912USA 中国科学院地质与地球物理研究所北京100029 山东大学空间科学研究院山东省光学天文与日地空间环境重点实验室威海264209 吉林大学地球探测科学与技术学院长春130026 中国地质大学(北京)地球科学与资源学院北京100083 中国地质科学院地质研究所北京100037 内蒙古工业大学资源与环境工程学院呼和浩特010051 中国科学院比较行星学卓越创新中心合肥230026

月球地质年代表将月球的地层按形成的时间顺序划分为不同的时代,能够清晰地表达月球的整体演化历史.在地基望远镜观测和阿波罗时代早期,由于当时所用数据的空间覆盖度和分辨率有限,所建立的月球地质年代划分存在部分缺陷.在阿波罗时代... 详细信息

月球地质年代表将月球的地层按形成的时间顺序划分为不同的时代,能够清晰地表达月球的整体演化历史.在地基望远镜观测和阿波罗时代早期,由于当时所用数据的空间覆盖度和分辨率有限,所建立的月球地质年代划分存在部分缺陷.在阿波罗时代结束以来的几十年里,人类对月球进行了更广泛的研究,拓展了对全月地质演化的认识和理解.基于对月球动力学演化的综合性分析,本文对当前的月球地质年代表进行了更新,特别考虑了内动力地质作用和外动力地质作用在月球早期演化中所发挥的作用.首先,根据内动力和外动力在不同时期对月球改造的效应,提出了三阶段月球动力学演化模型,并建立了三个相应的“宙/宇”级别的年代及地层单元.其次,为了更清晰地反映月球的演化历史,以南极-艾肯(SPA)盆地的形成为界线将前酒海纪划分为了岩浆洋纪和艾肯纪,其中较年轻的艾肯纪是以SPA盆地的形成为起点.本文识别了SPA盆地的溅射物地层,即达斯建造,其沉积在月球的原始月壳上,是岩浆洋结束后保存下来的最古老的外动力成因地层.更新的月球地质年代表系统综合了阿波罗时期以来月球探测和研究的成果,构建了一个描述月球演化历史的系统框架,能够更方便地开展月球地质研究,对其他类地行星的地质演化研究也具有重要的参考意义.

关键词：月球地质年代表演化历史内动力作用外动力作用

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