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Discussion of liquid threshold pressure gradient

Petroleum 2017年第2期3卷 232-236页

作者： Xiukun Wang james j.Sheng Texas Tech University USA Southwest Petroleum University China

Some authors believe that a minimum pressure gradient(called threshold pressure gradient(TPG))is required before a liquid starts to flow in a porous *** a tight or shale oil formation,this TPG phenomenon becomes more important,as it is more difficult for a fluid to *** this paper,experimental data on TPG published in the literature are carefully *** we found is that a very low flow velocity corresponding to a very low pressure gradient cannot be measured in the *** can only be done above some measurable flow *** these flow velocities and their corresponding pressure gradients are plotted in an XY plot and extrapolated to zero velocity,a non-zero pressure gradient corresponds to this zero *** non-zero pressure gradient is called threshold pressure gradient in the ***,in the regime of very low velocity and very low pressure gradient,the data gradually approach to the origin of the plot,demonstrating a non-linear relationship between the pressure gradient and the *** the data do not approach to a point of zero velocity and a threshold pressure ***,the concept of threshold pressure gradient is a result of data misinterpretation of available experimental *** correct interpretation is that there are two flow regimes:nonlinear flow regime(non-Darcy flow regime)when the pressure gradients are low,and linear flow regime(Darcy flow regime)when the pressure gradient is intermediate or *** nonlinear flow regime starts from the origin *** the pressure gradient is increased,the curve becomes a straight line demonstrating the linear flow *** have verified our views by first analyzing the causes of non-Darcy flow,and then systematically analyzed typical experimental data and correlations in the *** conclude that TPG does not *** also use several counter examples to support our conclusion.

关键词： Low velocity non-Darcy flow Threshold pressure gradient Shale oil reservoirs Tight oil reservoirs

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Competition for food in 2 populations of a wild-caught fish

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Current Zoology 2018年第5期64卷 615-622页

作者： Pierre j.C. CHUARD Grant E. BROWN james W.A. GRANT Research School of Biology The Australian National University Canberra ACT 0200 Australia Departmentof Biology Concordia University 7141 Sherbrooke Street West Montreal Quebec Canada H4B 1R6

Aggressive behavior when competing for resources is expected to increase as the ratio of competitors-to-resource ratio （CRR） units increases. Females are expected to be more aggressive than males when competing for food when body size is more strongly related to reproductive suc- cess in females than in males, whereas aggression is predicted to decrease under high ambient predation risk by natural selection. Under the risk allocation model, however, individuals under high ambient predation risk are expected to be more aggressive, and forage more in the absence of imminent risk than their low risk counterparts. An interaction between adult sex ratio （i.e., adult males/females）, ambient predation risk （high vs. low）, and sex on intrasexual competition for mates in Trinidadian guppies Poecilia reticulata has been shown. The interaction suggested an increase in aggression rates as CRR increased, except for males from the high predation population. To compare the patterns of competition for food versus mates, we replicated this study by using food patches. We allowed 4 male or 4 female guppies from high and low predation populations to com- pete for 5, 3, or 1 food patches. The foraging rate was higher in a high rather than low ambient pre- dation risk population. Surprisingly, CRR, sex, and population of origin had no effect on aggression rates. Despite other environmental differences between the 2 populations, the effect of ambient predation risk may be a likely explanation for differences in foraging rates. These results highlight the importance for individuals to secure food despite the cost of competition and predation.

关键词： aggression competitor-to-resource ratio foraging Poecifia reticulata population differences predation risk sex

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Arthropod prey of imported fire ants （Hymenoptera： Formicidae） in Mississippi sweetpotato fields

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Insect Science 2013年第4期20卷 467-471页

作者： Tahir Rashid jian Chen james T. Vogt Paul j. McLeod Aicorn State University Extension~Research Demonstration Farm & Tech Transfer Center Mound Bayou Mississippi USDA ARS Bio- logical Control of Pests Research Unit Stoneville Mississippi USDA FS Inventory & Analysis Knoxville Tennessee Department of Entomology University of Arkansas Fayetteville Arkansas United States

The red imported fire ants, Solenopsis invicta （Buren）, are generally considered pests. They have also been viewed as beneficial predators feeding on other insect pests of various agroecosystems. This study documents the foraging habits of fire ants in a sweetpotato field in Mississippi. Fire ant foraging trails connecting outside colonies to a sweetpotato field were exposed and foraging ants moving out of the field toward the direction of the colony were collected along with the solid food particles they were carrying. The food material was classified as arthropod or plant in origin. The arthropod particles were identified to orders. Fire ant foragers carried more arthropods than plant material. Coleoptera and Homoptera were the most abundant groups preyed upon. These insect orders contain various economically important pests of sweetpotato. Other major hexapod groups included the orders Hemiptera, Diptera and Collembola. The quantity of foraged material varied over the season. No damage to sweetpotato roots could be attributed to fire ant feeding. Imported fire ant foraging may reduce the number of insect pests in sweetpotato fields.

关键词： foraging imported fire ant predation Solenops& invicta sweetpotato

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Seasonal Dynamics of Turbidity Maximum in the Muthupet Estuary, India

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journal of Ocean University of China 2015年第5期14卷 765-777页

作者： PRIYA K.L. jEGATHAMBAL P. james E.j. School of Civil Engineering Karunya University

Results are presented of the longitudinal and vertical profiling of salinity and suspended particulate matter(SPM) at the Muthupet estuary, India, during a one year period under widely varying freshwater flow conditions. Freshwater flow was available during post-monsoon and monsoon. An up-estuary shift in the location of estuarine turbidity maxima(ETM) was observed during the transition from post-monsoon to pre-monsoon and further it shifted downstream during the transition from pre-monsoon to monsoon, thereby exhibiting a pronounced seasonal cycle. The salinity intrusion was dependent on the freshwater discharge and was expressed as a power function of freshwater flow, explaining 97% of the variance. The formation of a salt plug in Muthupet estuary and its seasonal dynamics were observed, which is not an identified feature of any of the Indian estuaries studied so far. The geographical positions of salt plug and ETM core were more or less the same during their formation. The occurrence of two ETM during the LW of post-monsoon and the absence of ETM during monsoon explains the strong seasonal variation in the formation of ETM. The primary factor affecting the formation of ETM was identified as the freshwater flow over an annual cycle; the resuspension of sediments by tidal current affecting the formation on a flood/ebb cycle was secondary. The extent of shift of ETM was found to be an inverse logarithmic function of the freshwater discharge. The separation between ETM intrusion and salinity intrusion increased two fold with the increase in ETM intrusion.

关键词： estuarine turbidity maximum salinity intrusion suspended particulate matter salt plug Muthupet estuary, India

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Peptide asparaginyl ligases——renegade peptide bond makers

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Science China Chemistry 2020年第3期63卷 296-307页

作者： james P.Tam Ning-Yu Chan Heng Tai Liew Shaun j.Tan Yu Chen School of Biological Sciences Nanyang Technological UniversitySingapore 637551Singapore Synzymes and Natural Products Center Nanyang Technological UniversitySingapore 637551Singapore NTU Institute of Structural Biology Nanyang Technological UniversitySingapore 636921Singapore

Making peptide bonds is tightly controlled by genetic code and machinery which includes cofactors,ATP,and *** this regard,the stand-alone and genetic-code-independent peptide ligases constitute a new family of renegade peptide-bond makers.A prime example is butelase-1,an Asn/Asp(Asx)-specific ligase that structurally belongs to the asparaginyl endopeptidase ***-1 specifically recognizes a C-terminal Asx-containing tripeptide motif,Asn/Asp-Xaa-Yaa(Xaa and Yaa are any amino acids),to form a site-specific Asn-Xaa peptide bond either intramolecularly as cyclic proteins or intermolecularly as modified *** work in the past five years has validated that butelase-1 is a potent and versatile *** we review the advances in ligases,with a focus on butelase-1,and their applications in engineering bioactive peptides and precision protein modifications,antibody-drug conjugates,and live-cell labeling.

关键词： asparaginyl endopeptidase Asn-specific ligation bioorthogonal ligation butelase chemoenzymatic ligation live-cell labeling protein engineering protein modification site-specific labeling tandem ligation

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Migmatite-like textures in anthracite:Further evidence for low-grade metamorphic melting and resolidification in high-rank coals

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Geoscience Frontiers 2021年第3期12卷 428-436页

作者： james C.Hower Susan M.Rimmer Maria Mastalerz Nicola j.Wagner University of Kentucky Center for Applied Energy Research 2540 Research Park DriveLexingtonKY 40511USA School of Earth Systems and Sustainability Southern Illinois University CarbondaleCarbondaleIL 62901USA Indiana Geological&Water Survey Indiana UniversityBloomingtonIN 47405USA Department of Geology University of JohannesburgJohannesburgSouth Africa

Previous studies demonstrated that melting,initiated by supercritical fluids in the 375-400℃range,occurred as part of anthracite metamorphism in the Appalachian *** on the known behavior of vitrinite at high temperatures and,to a lesser extent,at high pressures,it was determined that the duration of the heating,melting,and resolidification event was about 1 *** the current study,featureless vitrinite within banded maceral assemblages demonstratesthe intimate association of melted and resolidified vitrinite with anthracite-rank *** analogy with metamorphosed inorganic rocks,such associations represent diadysites and embrechites,i.e.,cross-cutting and layered migmatites,*** though the temperature of formation of the anthracite structures is several hundred℃lower than that seen in metamorphosed inorganic rocks,anthracites are metamorphic rocks and the nomenclature for metamorphic rocks may be appropriate for coal.

关键词： Igneous Metamorphic texture Pennsylvania Mesozoic basins South Africa

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Leading Approaches to Vascularize Kidney Constructs in Tissue Engineering

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Engineering 2022年第12期19卷 117-127页

作者： Diana S.Lim john D.jackson Anthony Atala james j.Yoo Wake Forest Institute for Regenerative Medicine Wake Forest University School of MedicineMedical Center BoulevardNC 27157USA

There is an unprecedented need for new treatments for renal failure,as the incidence of this disease is increasing disproportionately to advancements in *** treatments are limited by the availability of viable organs,for which there is a worldwide *** treatment modalities also require a substantial amount of infrastructure,significantly limiting the access to care in most *** tissue engineering approaches promise to develop alternative solutions that address many of the inadequacies in current *** many advancements have been made—primarily in the past decade—in biofabrication and whole-organ tissue engineering,many challenges *** major hindrance to the progress of current tissue engineering approaches is establishing successful vascularization of developed engineered tissue *** review focuses on the recent advancements that address the vascular challenge,including the biofabrication of vasculature,whole-organ engineering through decellularization and recellularization approaches,microscale organogenesis,and vascularization using organoids in the context of kidney tissue *** also highlight the specific challenges that remain in developing successful strategies capable of clinical translation.

关键词： Kidney Vascularization Tissue engineering Biofabrication Organoids

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Large-diameter trees, snags, and deadwood in southern Utah, USA

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Ecological Processes 2021年第1期10卷 130-141页

作者： james A.Lutz Soren Struckman Tucker j.Furniss joseph D.Birch Larissa *** Darren j.McAvoy Department of Wildland Resources S.J.and Jessie E.Quinney College of Natural ResourcesUtah State University5230 Old Main HillLoganUT 84322-5230USA. Department of Renewable Resources University of AlbertaEdmontonAlbertaCanada.

Background:The epidemic Dendroctonus rufipennis(spruce beetle)outbreak in the subalpine forests of the Colorado Plateau in the 1990s killed most larger Picea engelmannii(Engelmann spruce)*** quarter century later,the larger snags are beginning to fall,transitioning to deadwood(down woody debris)where they may influence fire behavior,regeneration,and habitat ***:We tracked all fallen trees≥1 cm in diameter at breast height(1.37-m high)and mapped all pieces of deadwood≥10-cm diameter and≥1 m in length within 13.64 ha of a high-elevation mixed-species forest in the Picea–Abies zone annually for 5 years from 2015 through *** examined the relative contribution of Picea engelmannii to snag and deadwood pools relative to other species and the relative contributions of large-diameter trees(≥33.2 cm at this subalpine site).We compared spatially explicit mapping of deadwood to traditional measures of surface fuels and introduce a new method for approximating vertical distribution of ***:In this mixed-species forest,there was relatively high density and basal area of live Picea engelmannii 20 years after the beetle outbreak(36 trees ha^(−1) and 1.94 m^(2) ha^(−1)≥10-cm diameter)contrasting with the near total mortality of mature Picea in forests *** from tree boles≥10-cm diameter on the ground had biomass of 42 Mg ha^(−1),7 Mg ha^(−1) of Picea engelmannii,and 35 Mg ha^(−1) of other *** live aboveground biomass was 119 Mg ha^(−1),while snag biomass was 36 Mg ha^(−1).Mean total fuel loading measured with planar transects was 63 Mg ha^(−1) but varied more than three orders of magnitude(0.1 to 257 Mg ha^(−1)).Planar transects recorded 32 Mg ha^(−1) of wood≥7.62-cm diameter compared to the 42 Mg ha^(−1) of wood≥10-cm diameter recorded by explicit *** pieces of deadwood were often stacked,forming a vertical structure likely to contribute to active fire ***:Bark beetle mortality in the 1990s has made

关键词： Cedar Breaks National Monument Dendroctonus rufipennis Utah Forest Dynamics Plot Vertical fuel structure

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Murine lung eosinophil activation and chemokine production in allergic airway inflammation

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Cellular & Molecular Immunology 2010年第5期7卷 361-374页

作者： C Edward Rose jr joanne A Lannigan Paul Kim james j Lee Shu Man Fu Sun-sang j Sung Division of Pulmonary and Critical Care Department of MedicineUniversity of Virginia School of MedicineCharlottesvilleVAUSA Department of Microbiology University of Virginia School of MedicineCharlottesvilleVAUSA Center for Immunity Inflammationand Regenerative Medicine and Division of NephrologyDepartment of MedicineUniversity of Virginia School of MedicineCharlottesvilleVAUSA Division of Pulmonary Medicine Department of Biochemistry and Molecular BiologyMayo Clinic ArizonaScottsdaleAZUSA

Eosinophils play important roles in asthma and lung *** models are widely used for assessing the functional significance and mechanistic basis for eosinophil involvements in these ***,little is known about tissue eosinophils in *** addition,little data on eosinophil chemokine production during allergic airway inflammation are *** this study,the properties and functions of homeostatic and activated eosinophils were *** from normal tissues expressed costimulation and adhesion molecules B7-1,B7-2 and ICAM-1 for Ag presentation but little major histocompatibility complex(MHC)class II,and were found to be poor stimulators of T-cell ***,these eosinophils expressed high levels of chemokine mRNA including C10,macrophage inflammatory protein(MIP)-1a,MIP-1c,MIP-2,eotaxin and monocyte chemoattractant protein-5(MCP-5),and produced chemokine *** intracellular chemokines decreased rapidly with concomitant surface marker downregulation upon in vitro culturing consistent with piecemeal *** eosinophils from mice with induced allergic airway inflammation exhibited increased chemokines mRNA expression and chemokines protein production and upregulated MHC class II and CD11c *** were also found to be the predominant producers of the CCR1 ligands CCL6/C10 and CCL9/MIP-1c in inflamed *** production of C10 and MIP-1c correlated with the marked influx of CD11bhigh lung dendritic cells during allergic airway inflammation and the high expression of CCR1 on these dendritic cells(DCs).The study provided baseline information on tissue eosinophils,documented the upregulation of activation markers and chemokine production in activated eosinophils,and indicated that eosinophils were a key chemokine-producing cell type in allergic lung inflammation.

关键词： allergy chemokines eosinophils lung mouse

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Development and application of molecular gut-content analysis to detect aphid and coccinellid predation by Harmonia axyridis （Coleoptera： Coccinellidae）in Italy

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Insect Science 2015年第6期22卷 719-730页

作者： Gabriele Rondoni Kacie j. Athey james D. Harwood Eric Contit Carlo Ricci john j. Obrycki Department of Agricultural Food and Environmental Sciences University of Perugia Borgo XX Giugno 74 Perugia 06121 Italy and Department of Entomology University of Kentucky S-225 Agricultural Science Center North Lexington KY 40546-0091 USA

Despite their positive effect in reducing pest populations, exotic generalist predators sometimes become invasive and contribute to the displacement of indigenous species in the same trophic level. Although laboratory experiments have linked intraguild predation （IGP） to these interactions, field evidence and quantification of IGP are still lacking for most systems. The recent establishment of the exotic Harmonia axyridis （Pallas）（Coleoptera： Coccinellidae） in Italy raises concern about the detrimental effect that the ladybird could have on native coccinellids. Here we assessed, under laboratory conditions, the acceptability and suitability of eggs of 2 native ladybirds, Adalia bipunctata L. and Oenopia conglobata （L.）, as prey items for H. axyridis larvae. Then we developed primers for molecular gut-content analysis to detect predation by H. axyridis on the 2 ladybirds and on the aphid Eucallipterus tiliae L. Species-specific 16S primers were developed for the 3 species and laboratory feeding trials were conducted to quantify the rate of prey DNA breakdown in the gut of//. axyridis. Moreover, to field evaluate primers, H. axyridis 4th instars （n = 132） were systematically collected from linden trees in northern Italy and screened for the presence of prey DNA. Seventy-three percent and 7% of field collected H. axyridis were positive for aphid and coccinellid DNA, respectively. Predation upon aphid and A. bipunctata was lower than predicted if density dependent consumption was expected, while predation upon O. conglobata was significantly higher. Here, we provided the first evidence of IGP among feral populations ofH. axyridis and indigenous ladybird beetles, occurring in Italy.

关键词： Adalia bipunctata biological control Eucallipterus tiliae intraguild inter-actions nontarget effect Oenopia conglobata

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