نتایج جستجو برای: spatial gradients

تعداد نتایج: 394873  

Journal: :Cold Spring Harbor perspectives in biology 2009
Robert A Arkowitz

Chemical gradients of peptide mating pheromones are necessary for directional growth, which is critical for yeast mating. These gradients are generated by cell-type specific secretion or export and specific degradation in receiving cells. Spatial information is sensed by dedicated seven-transmembrane G-protein coupled receptors and yeast cells are able to detect extremely small differences in l...

2014
Nelson Valdivia María J. Díaz Jorge Holtheuer Ignacio Garrido Pirjo Huovinen Iván Gómez

Understanding the variation of biodiversity along environmental gradients and multiple spatial scales is relevant for theoretical and management purposes. Hereby, we analysed the spatial variability in diversity and structure of intertidal and subtidal macrobenthic Antarctic communities along vertical environmental stress gradients and across multiple horizontal spatial scales. Since biotic int...

Journal: :Langmuir : the ACS journal of surfaces and colloids 2004
Jason A Burdick Ali Khademhosseini Robert Langer

A method of fabricating photo-cross-linked hydrogels with gradients of immobilized molecules and crosslinking densities is introduced. Two macromer/initiator solutions are injected into a unique poly(dimethylsiloxane) channel system that produces a prepolymer gradient that is subsequently polymerized into a water-swollen hydrogel with ultraviolet light exposure. The gradient is controlled by th...

2012
Amedeo Chiribiri Gilion Hautvast Tim Lockie Andreas Schuster Boris Bigalke Luca Olivotti Simon Redwood Marcel Breeuwer Eike Nagel Sven Plein

Background The subendocardial layer of the myocardium is more sensitive to ischaemia than the subepicaridal layer due to interactions between myocardial contraction and blood supply. The transmural perfusion gradients observed in coronary heart disease (CAD) can be visualised with high spatial resolution myocardial perfusion CMR. These gradients are characterised by the extent and intensity of ...

Journal: :Developmental cell 2015
Björn Hegemann Michael Unger Sung Sik Lee Ingrid Stoffel-Studer Jasmin van den Heuvel Serge Pelet Heinz Koeppl Matthias Peter

Directional cell growth requires that cells read and interpret shallow chemical gradients, but how the gradient directional information is identified remains elusive. We use single-cell analysis and mathematical modeling to define the cellular gradient decoding network in yeast. Our results demonstrate that the spatial information of the gradient signal is read locally within the polarity site ...

Journal: :Bioinformatics 2006
Jordi Vidal Rodríguez Jaap A. Kaandorp Maciej Dobrzynski Joke G. Blom

MOTIVATION Many biochemical networks involve reactions localized on the cell membrane. This can give rise to spatial gradients of the concentration of cytosolic species. Moreover, the number of membrane molecules can be small and stochastic effects can become relevant. Pathways usually consist of a complex interaction network and are characterized by a large set of parameters. The inclusion of ...

2007
Jana M. McPherson Walter Jetz

Aim Studies exploring the determinants of geographical gradients in the occurrence of species or their traits obtain data by: (1) overlaying species range maps; (2) mapping survey-based species counts; or (3) superimposing models of individual species’ distributions. These data types have different spatial characteristics. We investigated whether these differences influence conclusions regardin...

2010
Bo Hu Wen Chen Wouter-Jan Rappel Herbert Levine

Many eukaryotic cells are able to sense chemical gradients by directly measuring spatial concentration differences. The precision of such gradient sensing is limited by fluctuations in the binding of diffusing particles to specific receptors on the cell surface. Here, we explore the physical limits of the spatial sensing mechanism by modeling the chemotactic cell as an Ising spin chain subject ...

Journal: :Physical review letters 2010
Bo Hu Wen Chen Wouter-Jan Rappel Herbert Levine

Many eukaryotic cells are able to detect chemical gradients by directly measuring spatial concentration differences. The precision of such gradient sensing is limited by fluctuations in the binding of diffusing particles to specific receptors on the cell surface. Here, we explore the physical limits of the spatial sensing mechanism by modeling the chemotactic cell as an Ising spin chain subject...

2016
Fabio Leonardo Meza‐Joya Mauricio Torres

Although biodiversity gradients have been widely documented, the factors governing broad-scale patterns in species richness are still a source of intense debate and interest in ecology, evolution, and conservation biology. Here, we tested whether spatial hypotheses (species-area effect, topographic heterogeneity, mid-domain null model, and latitudinal effect) explain the pattern of diversity ob...

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