检索结果-南通市图书馆

Metabolic collaboration between cells in the tumor microenvironment has a negligible effect on tumor growth

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

The Innovation 2024年第2期5卷 107-114页

作者： j.han Gustafsson Fariba Roshanzamir Anders Hagnestål Sagar M.Patel Oseeyi I.Daudu donald F.Becker j.nathan L.Robinson j.ns Nielsen Department of Life Sciences Chalmers University of TechnologySE-41296 GothenburgSweden Hagnesia AB SE-43854 HindåsSweden Department of Biochemistry and Redox Biology Center University of Nebraska-LincolnLincolnNE 68588USA BioInnovation Institute DK2200 CopenhagenDenmark

The tumor microenvironment is composed of a complex mixture of different cell types interacting under conditions of nutrient deprivation,but the metabolism therein is not fully understood due to difficulties in measuring metabolic fluxes and exchange of metabolites between different cell types in ***-scale metabolic modeling enables estimation of such exchange fluxes as well as an opportunity to gain insight into the metabolic behavior of individual cell ***,we estimated the availability of nutrients and oxygen within the tumor microenvironment using concentration measurements from blood together with a metabolite diffusion *** addition,we developed an approach to efficiently apply enzyme usage constraints in a comprehensive metabolic model of human *** combined modeling reproduced severe hypoxic conditions and the Warburg effect,and we found that limitations in enzymatic capacity contribute to cancer cells’preferential use of glutamine as a substrate to the citric acid ***,we investigated the common hypothesis that some stromal cells are exploited by cancer cells to produce metabolites useful for the cancer *** identified over 200 potential metabolites that could support collaboration between cancer cells and cancer-associated fibroblasts,but when limiting to metabolites previously identified to participate in such collaboration,no growth advantage was *** work highlights the importance of enzymatic capacity limitations for cell behaviors and exemplifies the utility of enzyme-constrained models for accurate prediction of metabolism in cells and tumor microenvironments.

关键词： metabolism effect limitations

Effect of particle stress tensor in simulations of dense gas-particle flows in fluidized beds

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Particuology 2018年第3期16卷 31-43页

作者： Mohammad Reza Haghgoo donald j. Bergstrom Raymond j. Spiteri Department of Mechanical Engineering University of Saskatchewan Saskatoon SK SFN 5A9 Canada Department of Computer Science University of Saskatchewan Saskatoon. SK S7N 5C9 Canada

A two-fluid model based on the kinetic theory of granular flow for the rapid-flow regime and the Coulomb friction law for the quasi-static regime is applied to predict the hydrodynamics of dense gas-particle flow in a three-dimensional fluidized bed. Two different models for the particle stress tensor that use different constitutive equations in the elastic-inertial regime are examined to assess their ability to predict bed dynamics. To understand how particle stress models affect structural features of the flow, a quantitative analysis is performed on some important aspects of the mechanics of bubbling beds that have received relatively little attention in the literature. Accordingly, different flow regimes are identified in the context of fluidized beds through the dimensionless inertial number, and the main characteristics of each regime are discussed. In addition, how the particle stress tensor manifests itself in the bubble characteristics, natural frequency of the bed, and particle Reynolds stress are investigated, all of which help to better understand the complex dynamics of the fluidized bed. The numerical results are validated against pub- lished experimental data and demonstrate the significant role of the stress tensor in the elastic-inertial regime.

关键词： Two-fluid model Inertial number Fluidized bed Flow regime Particle Reynolds stress MFIX

Bioacoustic variation of swimbladder disturbance sounds in Neotropical doradoid catfishes （Siluriformes： Doradidae, Auchenipteridae）： Potential morphological correlates

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Current Zoology 2012年第1期58卷 171-188页

作者： Kaatz, Ingrid M. Stewart, donald j. Department of Environmental and Forest Biology SUNY College of Environmental Science and Forestry Syracuse NY 13210 USA

Swimbladder disturbance sounds of doradoid catfishes （Doradidae and Aucheniptefidae） demonstrated striking waveform and spectrographic variation. We surveyed sounds of 25 doradoid species in 20 genera comparing these to sounds of four vocal outgroup catfish families. Sounds were either continuous waveforms （lacking interpulses） or pulsed （groups of pulses repeated at fixed temporal intervals）. This is the first evidence for swimbladder calls with fixed interpulse patterns in catfishes. Vocal mechanism components that were similar between doradids and auchenipterids included： swimbladder shape, swimbladder dimensions and sonic muscle-somatic index. Morphological traits that showed variation among taxa and were evaluated for po- tential correlates of call diversity are： 1） diverticula （marginal outpocketings of the swimbladder with no connection to inner ear） and 2） elastic spring apparatus Mtillerian rami （ESA-Mr）. Within the doradid subfamilies and within the Auchenipteridae most species differed significantly in dominant frequency with frequency ranges overlapping to some extent for most. Doradid swim- bladder diverticula did not explain dominant frequency variation within the doradoid superfamily. Some doradids with conical ESA-Mr had the highest dominant frequency sounds. Auchenipterids included both relatively lower and higher dominant fre- quency sound producers but lacked diverticula and had discoidal ESA-Mr. Comparing a phylogeny of doradoid genera with out- group taxa, we infer that complex diverticula and conical ESA-Mr are derived characters within the Doradidae. Species repre- senting outgroup families produced either continuous lower dominant frequency sounds （aspredinids, mochokids and pseudopimelodids） or pulsed higher dominant frequency sounds （pimelodids） [Current Zoology 58 （1）： 171-188, 2012].

关键词： Catfishes Communication Signal evolution Vocal mechanisms

Characterization of Kiwifruit Xyloglucan

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

j.urnal of Integrative Plant Biology 2009年第10期51卷 933-941页

作者： Xingj.n Li Naoki Sakurai donald j. Nevins Academy of the State Administration of Grains Beijing 100037 China Graduate School of Biosphere Science Hiroshima University Kagamiyama 1-7-1 Higashi-hiroshima 739-8521 Japan Department of Plant Sciences University of California Davis CA 95616 USA

Structural characteristics of xyloglucan are constant in the pericarp cell walls of kiwifruit （Actinidia deliciosa） throughout fruit enlargement and maturation. Most of the xyioglucan （XG） persists in the cell walls of ripe kiwifruit. XG from the pericarp tissues of 36-h ethylene-treated kiwifruit was extracted as hemicellulose Ⅱ （HC-Ⅱ） with 4.28 M KOH containing 0.02% NaBH4, and purified using iodine precipitation and subsequent anion-exchange chromatography. This purifying protocol increased XG purity from 50 mol% in HC-Ⅱ fraction to 62 mol% in the purified XG powder. The molar ratio of glucose： xylose： galactose： fucose in the purified XG was 10： 6.9： 2.1： 0.3. Gel permeation chromatography indicated that purified XG had an average molecular-mass of 161 KDa, a value that exceeds the 95 KDa Mr determined for total polymeric sugars. Sugar linkage analysis confirmed the lack of fucose in the kiwifruit XG, but a small amount of arabinoxylan and low Mr glucomannan remained associated with this fraction.

关键词： Actinidia deliciosa cell walls glucomannan hemicellulose sugar linkage analysis xyloglucan

Characterization of Binding Sites of Eukaryotic Transcription Factors

在线全文

学校读者我要写书评

暂无评论

Genomics, Proteomics & Bioinformatics 2006年第2期4卷 67-79页

作者： j.ang Qian j.mmy Lin donald j. Zack The Wilmer Institute Department of Molecular Biology and Genetics Department of Neuroscience McKusick-Nathans Institute of Genetic Medicine Johns Hopkins University School of Medicine Baltimore MD 21287 USA.

To explore the nature of eukaryotic transcription factor （TF） binding sites and determine how they differ from surrounding DNA sequences, we examined four features associated with DNA binding sites： G＋C content, pattern complexity, palindromic structure, and Markov sequence ordering. Our analysis of the regulatory motifs obtained from the TRANSFAC databases using yeast intergenic sequences as background, revealed that these four features show variable enrichment in motif sequences. For example, motif sequences were more likely to have palindromic structure than were background sequences. In addition, these features were tightly localized to the regulatory motifs, indicating that they are a property of the motif sequences themselves and are not shared by the general promoter ＂environment＂ in which the regulatory motifs reside. By breaking down the motif sequences according to the TF classes to which they bind, more specific associations were identified. Finally, we found that some correlations, such as G＋C content enrichment, were species-specific, while others, such as complexity enrichment, were universal across the species examined. The quantitative analysis provided here should increase our understanding of protein-DNA interactions and also help facilitate the discovery of regulatory motifs through bioinformatics.

关键词： transcription factor promoter gene regulation bioinformatics

Storylines of family medicine Ⅴ:ways of thinking—honing the therapeutic self

在线全文

学校读者我要写书评

暂无评论

Family Medicine and Community Health 2024年第S3期12卷 43-51页

作者： William B Ventres Leslie A Stone j.hanna F Shapiro Cynthia Haq j.ssica R B Leao donald E Nease j. Liz Grant Stewart W Mercer j.hn C M Gillies Pablo González Blasco Maria Auxiliadora C De Benedetto Graziela Moreto Marcelo R Levites j.nnifer E DeVoe William R Phillips j.ne M Uygur Thomas R Egnew Colette S Stanley Family and Preventive Medicine University of Arkansas for Medical Sciences College of MedicineLittle RockArkansasUSA Family Medicine University of California Irvine School of MedicineIrvineCaliforniaUSA Faculty of Medicine University of Sao PauloSao PauloBrazil Family Medicine University of Colorado Anschutz Medical Campus School of MedicineAuroraColoradoUSA Usher Institute Edinburgh Medical SchoolUniversity of EdinburghEdinburghUK SOBRAMFA-Medical Education and Humanism Sao PauloBrazil Family Medicine Oregon Health&Science University School of MedicinePortlandOregonUSA Family Medicine University of Washington School of MedicineSeattleWashingtonUSA General Practice Royal College of Surgeons in IrelandDublinIreland General Internal Medicine Geriatrics&Palliative MedicineTulane University School of MedicineNew OrleansLouisianaUSA

Storylines of Family Medicine is a 12-part series of thematically linked essays with accompanying illustrations that explore the many dimensions of family medicine,as interpreted by individual family physicians and medical educators in the USA and elsewhere around the ***‘Ⅴ:ways of thinking—honing the therapeutic self’,authors present the following sections:‘Reflective practice in action’,‘The doctor as drug—Balint groups’,‘Cultivating compassion’,‘Towards a humanistic approach to doctoring’,‘Intimacy in family medicine’,‘The many faces of suffering’,‘Transcending suffering’and‘The power of listening to stories.’May readers feel a deeper sense of their own therapeutic agency by reflecting on these essays.

关键词： illustration dimensions suffering

A SURVEY OF THE HOLARCTIC LINYPHIIDAE (ARANEAE),A REVIEW OF THE ERIGONINE GENUS ZORNELLA j.CKSON, 1932

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

动物分类学报 2007年第1期32卷 21-34页

作者： Yuri M. Marusik donald j. Buckle Seppo Koponen Institute for Biological Problems of the North Portovaya Str. 18 Magadan 685000 Russia 620 Albert Avenue Saskatoon Saskatchewan S7N 1G7 Canada Zoological Museum University of Turku FI-20014 Turku Finland

The Holarctic erigonid genus Zornella has been surveyed. Four species are recognized in this genus, two Palaearctic: ***(***,11879) & *** ***., and two Nearctic: ***(Banks, 1906) & *** Chamberlin,*** is demonstrated that neither nearctic species is conspecific with *** as was thought by Holm and other authors. *** ***. is described from northeastern Siberia. All of the species are illustrated and their distributions mapped.

关键词： Spiders Araneae Erigoninae Holarctic Zornella new species redescription

Src Is Dephosphorylated at Tyrosine 530 in Human Colon Carcinomas

在线全文

学校读者我要写书评

暂无评论

Chinese j.urnal of Cancer Research 2011年第3期23卷 229-231页

作者： j.ffrey D Bj.rge donald j.Fuj.ta Department of Biochemistry and Molecular Biology and Southern Alberta Cancer Research InstituteUniversity of Calgary

Obj.ctive：Src is a protein tyrosine kinase that plays important roles in cancer development,and Src kinase activity has been found to be elevated in several types of ***,the cause of the elevation of Src kinase activity in the maj.rity of human colon carcinomas is still largely *** aim at finding the cause of elevated Src kinase activity in human colon ***：We employed normal colon epithelial FHC cells and examined Src activation in human colon carcinoma specimens from 8 *** expression levels were determined by Western blotting,and the activity of Src kinase by kinase ***：Actin levels were different between tumor and normal tissues,demonstrating the complexities and inhomogeneities of the tissue *** kinase activities were increased in the maj.rity of the colon carcinomas as compared with normal colon epithelial cells （range 13-29）.Src protein levels were reduced in the colon *** Y530 phosphorylation levels were reduced to a higher extent than protein levels in the ***：The results suggest that Src specific activities were highly increased in human colon carcinomas;phosphorylation at Src Y530 was reduced,contributing to the highly elevated Src specific activity and Src kinase activity.

关键词： Src Kinase activation Dephosphorylation Colon carcinoma

Time Scale of Partial Melting of KLB-1 Peridotite: Constrained from Experimental Observation and Thermodynamic Models

在线全文

学校读者我要写书评

暂无评论

j.urnal of Earth Science 2018年第2期29卷 245-254页

作者： Wei Du Li Li donald j.Weidner State Key Laboratory of Ore Deposit Geochemistry Institute of Geochemistry Chinese Academy of Sciences Mineral Physics Institute Department of Geosciences University of New York at Stony Brook

Partial melting experiments were carried on KLB-1 peridotite, a xenolith sample from the Earth＇s upper mantle, at 1.5 GPa and temperatures from 1 300 to 1 600 ℃, with heating time varies from 1 to 30 min. We quantify the axial temperature gradient in the deformation-DIA appa- ratus （D-DIA） and constrain the time scale of partial melting by comparing experimental observa- tions with calculated result from pMELTS program. The compositions of the liquid phase and the coexisting solid phases （clinopyroxene, orthopyroxene, and olivine） agree well with those calculated from pMELTS program, suggesting that local chemical equilibrium achieves during partial melting, although longer heating time is required to homogenize the bulk sample. The Mg# （=Mg/（Mg＋Fe） moi.%） of olivines from the 1-minute heating experiment changed continuously along the axial of the graphite capsule. A thermal gradient of 50 ℃/mm was calculated by comparing the Mg# of oli- vine grains with the output of pMELTS program. Olivine grains at the hot end of the graphite cap- sule from the three experiments heated at 1 400 ℃ but with different annealing time show consis- tence on Mg#, indicating that partitioning of Fe2＋ between the olivine grains and the silicate melt happened fast, and partial melting occurs in seconds.

关键词： peridotite partial melting temperature gradient pMELTS program.