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A new rat model of portal hypertension induced by intraportal injection of microspheres

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World Journal of Gastroenterology 1998年第1期4卷 71-74页

作者： LI Xiang-Nong IS benjamin B Alexander Department of Liver Surgery Affiliated Hospital Xuzhou Medical College Xuzhou 221002 China Department of Liver Surgery Affiliated Hospital Xuzhou Medical College China Xuzhou Medical College China Beijing Medical University China Department of Surgery King's College School and Dentistry United Kingdom Department of Liver Surgery Affiliated Hospital Xuzhou Medical College 50 Jiaheqian Street Xuzhou 221002 China Department of Surgery King's Coll. Sch. of Med. and Dent. London United Kingdom

IM To produce a new rat model of portal hypertension by intraportal injection of microspheres.METHODS Measured aliquots of single or differentsized microspheres (15, 40, 80μm) were injected into the portal vein to block intrahepatic portal radicals. The resultant changes in arterial, portal, hepatic venous and splenic pulp pressures were monitored. The liver and lungs were excised for histological examination.RESULTS Portal venous pressure was elevated from basal value of 089-102 kPa to a steadystate of 198-319 kPa following the sequential injections of single or differentsized microspheres, with a markedly lowered mean arterial pressure. However, a smalldose injection of 80μm microspheres (18×105) produced a steadystate portal venous pressure of 253±017 kPa, and all rats showed normal arterial pressures. In addition, numerous microspheres were found in the lungs in all experimental groups.CONCLUSION Portal hypertension can be reproduced in rats by intraportal injection of microspheres at a small dose of 80μm (18×105). Intrahepatic portalsystemic shunts probably exist in the normal rat liver..

关键词： portal vein hypertension,portal disease model,animal latex microsphere

Special Topic： Cretaceous greenhouse palaeoclimate and sea-level changes

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Science China Earth Sciences 2017年第1期60卷 1-4页

作者： XiuMian HU Michael WAGREICH benjamin SAMES State Key Laboratory of Mineral Deposits Research School of Earth Sciences and Engineering Nanjing University China Department of Geodynamics and Sedimentology Center for Earth Sciences University of Vienna Austria

Earth＇s climate has oscillated between greenhouse （warm） and icehouse （cold） modes throughout Earth history. At present, Earth is in the midst of an icehouse climate interval, despite the anthropogenic contribution to global warming and sea-level rise due to industrialization during the past two centuries. This led to a dramatic increase in atmospheric CO2, mainly caused by the extensive burning of fossils fuels. The Cretaceous （145 to 66 million years ago） is the youngest prolonged greenhouse climate interval in the Phanerozoic, marked by very high global mean temperatures with some extreme warming peaks （＇hothouse＇ or ＇supergreenhouse＇）, largely absence of permanent continental ice sheets, a mean global sea-level having been some 250 m higher than that of today, and levels of carbon dioxide 4 to 10 times higher than those of the pre-industrial era. If temperature will continue to rise as quickly as in the last three decades, we are close to being at the cusp to a new greenhouse climate interval facing quickly rising global sea-level and reaching atmospheric CO2 levels of the ＇Cretaceous supergreenhouse＇ in about the years 2190-2260 （Hay, 2011）. Evidence from Earth＇s history indicates that glacial-interglacial climate mode changes as well as past sea-level changes such as in the Cretaceous greenhouse occurred at rates orders of magnitude slower than observed at present. The recent rise in global sea-level in response to rising levels of atmospheric greenhouse gases, the associated global warm- ing, and the waning of continental ice shields is a primary concern for human society. To predict future sea-levels we need a better understanding of the record of past sea-level changes, especially in the greenhouse palaeoclimate modes. Therefore, understanding the Cretaceous palaeoclimate is essential for a more accurate prediction of future global climate, sea-level rise and environmental changes in a prospective ＇Cretaceous-like＇ greenhouse Earth.

关键词： greenhouse Cretaceous warming anthropogenic despite throughout

Test Elements, Generic Elements and Almost Primitivity in Free Products

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Algebra Colloquium 2016年第2期23卷 263-280页

作者： Ann-Kristin Engel benjamin Fine Gerhard Rosenberger Faculty of Mathematics TU-Braunschweig 38106 Braunschweig Germany Department of Mathematics Fairfield University Fairfield Connecticut 06430 USA Fachbereich Mathematik University of Hamburg Bundesstrasse 55 20146 Hamburg Germany FIM University of Passau Innstrasse 33 94032 Passau Germany

In [5, 6] the relationships between test words, generic elements, almost primitivity and tame almost primitivity were examined in free groups. In this paper we extend the concepts and connections to general free produ... 详细信息

关键词： test elements generic elements almost primitive elements free products

The OpenStreetMap folksonomy and its evolution

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Geo-Spatial Information Science 2017年第3期20卷 219-230页

作者： Franz-benjamin Mocnik Alexander Zipf Martin Raifer Institute of Geography Heidelberg UniversityHeidelbergGermany

The comprehension of folksonomies is of high importance when making sense of Volunteered Geographic Information(VGI),in particular in the case of OpenStreetMap(OSM).So far,only little research has been conducted to understand the role and the evolution of folksonomies in VGI and OSM,which is despite the fact that without a comprehension of the folksonomies the thematic dimension of data can hardly be *** article examines the history of the OSM folksonomy,with the aim to predict its future *** particular,we explore how the documentation of the OSM folksonomy relates to its actual use in the data,and we investigate the historical and future scope and granularity of the ***,a visualization technique is proposed to examine the folksonomy in more detail.

关键词： Volunteered Geographic Information(VGI) OpenStreetMap(OSM) folksonomy taxonomy evolution granularity visualization

The Civil Examination System in Late Imperial China, 1400-1900

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Frontiers of History in China 2013年第1期8卷 32-50页

作者： benjamin A, Elman Department Princeton University Princeton NJ 08544-1008 USA

Scholars often contend that civil examinations were what made imperial China a political meritocracy. They point to the examination system to show that the selection process served more as a common training program for literati than as a gate-keeper to keep non-elites out. Despite the symbiotic relations between the court and its literati, the emperor played the final card in the selection process. The asymmetrical relations between the throne and its elites nevertheless empowered elites to seek upward mobility as scholar-officials through the system. But true social mobility, peasants becoming officials, was never the goal of state policy in late imperial China; a modest level of social circulation was an unexpected consequence of the meritocratic civil service. Moreover, the meri^t-based bureaucracy never broke free of its dependence on an authoritarian imperial system. A modem political system might be more compatible with meritocracy, however. One of the unintended consequences of the civil examinations was creation of classically literate men （and women）, who used their linguistic talents for a variety of non-official purposes, from literati physicians to local pettifoggers, from fiction-writers to examination essay teachers, from Buddhist and Daoist monks to mothers and daughters. If there was much social mobility, i.e., the opportunity for members of the lower classes to rise in the social hierarchy, it was likely here. Rather than ＂social mobility,＂ this phenomenon might be better described as a healthy ＂circulation＂ of lower and upper elites when compared to aristocratic Europe and Japan.

关键词： Meritocracy civil service examinations late imperial China education reproduction

A conifer-dominated Early Triassic flora from Southwest China

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Science Bulletin 2018年第22期63卷 1462-1463页

作者： Zhuo Feng Haibo Wei Yun Guo benjamin Bomfleur Institute of Deep Time Terrestrial Ecology Yunnan UniversityKunming 650500China Research Center for Earth System Science Yunnan UniversityKunming 650500China Institute of Karst Geology Chinese Academy of Geological SciencesGuilin 541004China Forschungsstelle fur Paltiobotanik Westfalische Wilhelms-UniversitatHeisenbergstraβe 2Munster D-48149Germany

The end-Permian mass extinction is the greatest biotic crisis in Earth *** marine species (>95%)and many land tetrapods (>70%)disappeared within a very short time interval [1]. Previous studies of this dramatic event mainly have focused on evolutionary patterns in animal groups prior to the extinction, and on their recovery during the Early Triassic [2].Although some macroevolutionary scenarios have been postulated for the changes in land-plant vegetation through the Permian and Triassic,the severity of extinction and,the timing and radiation pattern in the recovery of plant groups during the Early Triassic are still debated [3].Hitherto there has been little information about plant life in the wake of the end-Permian extinction event,mainly because of the scarcity of records of earliest Triassic plant-bearing deposits *** we report on an Early Triassic flora from Southwest China that provides a rare glimpse into the post-extinction vegetation in the (sub)tropics of Cathavsia.

关键词：生物危机二叠纪三叠纪

A hybrid Monte Carlo study of bond-stretching electron–phonon interactions and charge order in BaBiO_(3)

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npj Computational Materials 2023年第1期9卷 1950-1958页

作者： benjamin Cohen-Stead Kipton Barros Richard Scalettar Steven Johnston Department of Physics and Astronomy The University of TennesseeKnoxvilleTN 37996USA Institute for Advanced Materials and Manufacturing The University of TennesseeKnoxvilleTN 37996USA Theoretical Division and CNLS Los Alamos National LaboratoryLos AlamosNM 87545USA Department of Physics and Astronomy University of CaliforniaDavisCA 95616USA

The relationship between electron–phonon(e-ph)interactions and charge-density-wave(CDW)order in the bismuthate family of high-temperature superconductors remains *** address this question using nonperturbative hybrid Monte Carlo calculations for the parent compound BaBiO_(3).Our model includes the Bi 6s and O 2pσorbitals and coupling to the Bi-O bond-stretching branch of optical phonons via modulations of the Bi-O hopping *** simulate three-dimensional clusters of up to 4000 orbitals,with input model parameters taken from ab initio electronic structure calculations and a phonon energyℏΩ0=60 *** results demonstrate that the coupling to the bond-stretching modes is sufficient to reproduce the CDW transition in this system,despite a relatively small dimensionless *** also find that the transition deviates from the weak-coupling Peierls’*** work demonstrates that off-diagonal e-ph interactions in orbital space are vital in establishing the bismuthate phase diagram.

关键词： stretching phonon charge

Arthropods and biofuel production systems in North America

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Insect Science 2010年第3期17卷 220-236页

作者： Douglas A. Landis benjamin P. Werling Department of Entomology and Great Lakes Bioenergy Research Center 204 Center for Integrated Plant Systems Michigan State University East Lansing Michigan USA

Biomass harvest may eventually be conducted on over 100 000 000 ha of US crop and forest lands to meet federally-mandated targets for renewable biofuels. Such largescale land use changes could profoundly impact working landscapes and the arthropod communities that inhabit them. We review the literature on dedicated biofuel crops and biomass harvest from forests to look for commonalities in arthropod community responses. With expanded biofuel production, existing arthropod pests of biofuel crops will likely become more important and new pests will emerge. Beneficial arthropods will also be influenced by biofuel crop habitats, potentially altering the distribution of pollination and pest control services to the surrounding landscape. Production of biofuel crops including initial crop selection, genetic improvement, agronomic practices, and harvest regimes will also influence arthropod communities. In turn, arthropods will impact the productivity and species composition of biomass production systems. Some of these processes have the potential to cause landscape-level changes in arthropod community dynamics and insect- vectored plant diseases. Finally, changes in arthropod populations and their spatiotemporal distribution in the landscape will have impacts on consumers of insects at higher trophic levels, potentially influencing their population and community dynamics and producing feedbacks to arthropod communities. Given that dedicated biofuel crops and intensified biomass harvest from forests are still relatively uncommon in North America, as they increase, we anticipate ＇predictably unpredictable＇ shifts in arthropod communities and the ecosystem services and functions they support. We suggest that research on arthropod dynamics within biofuel crops, their spillover into adjacent habitats, and implications for the sustainability of working landscapes are critical topics for both basic and applied investigations.

关键词： biodiversity land use change pest management

Topology-enhanced mechanical stability of swelling nanoporous electrodes

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npj Computational Materials 2023年第1期9卷 1161-1175页

作者： benjamin E.Grossman-Ponemon Ataollah Mesgarnejad Alain Karma Center for Interdisciplinary Research on Complex Systems Department of PhysicsNortheastern UniversityBostonMA 02115USA School of Engineering Brown UniversityProvidenceRI 02912USA

Materials like silicon and germanium offer a 10-fold improvement in charge capacity over conventional graphite anodes in lithium-ion batteries but experience a roughly threefold volume increase during lithiation,which challenges ensuring battery *** silicon,created by liquid-metal-dealloying,is a potentially attractive anode design to mitigate this challenge,exhibiting both higher capacity and extended cycle ***,how nanoporous structures accommodate the large volume change is ***,we address this question by using phase-field modeling to produce nanoporous particles and to investigate their elastoplastic swelling behavior and *** simulations show that enhanced mechanical stability results from the network topology consisting of ligaments connected by bulbous,sphere-like *** ligaments forcefully resist elongation while the nodes,behaving like isolated spherical particles,experience large stresses driving ***,being smaller compared to a sphere of the same volume as the entire nanoporous particle,the nodes are more protected against fracture.

关键词： swelling stability attractive