Search Results
Results 401 - 450 of 1912
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Volfson Dmitri - - 2008
The structure of bacterial populations is governed by the interplay of many physical and biological factors, ranging from properties of surrounding aqueous media and substrates to cell-cell communication and gene expression in individual cells. The biomechanical interactions arising from the growth and division of individual cells in confined environments are ...
Campbell Stuart G SG Department of Bioengineering, University of California, San Diego, La Jolla, CA 92093, - - 2008
The mechanical properties of myocardium vary across the transmural aspect of the left ventricular wall. Some of these functional heterogeneities may be related to differences in excitation-contraction coupling characteristics that have been observed in cells isolated from the epicardial, mid-myocardial and endocardial regions of the left ventricle of many species, ...
Backes Tracy M - - 2009
We construct and implement a stochastic model of convergent extension, using a minimal set of assumptions on cell behavior. In addition to the basic assumptions of volume conservation, random cell motion, and cell-cell and cell-ECM adhesion, and a non-standard assumption that cytoskeletal polymerization generates an internal pressure tending to keep ...
Chao Dennis L DL Vaccine and Infectious Disease Institute, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA. - - 2008
Clonal expansion of premalignant lesions is an important step in the progression to cancer. This process is commonly considered to be a consequence of sustaining a proliferative mutation. Here, we investigate whether the growth trajectory of clones can be better described by a model in which clone growth does not ...
Meireles, Martine
This study reports a numerical approach for modeling the hydraulic resistance of a filter cake of deformable cells. First, a mechanical and osmotic model that describes the volume fraction of solids in a bed of yeast cells as a function of the compressive pressure it experiences is presented. The effects ...
Meillaud, Fanny
A simple theoretical model for pin/nip-type muc-Si:H solar cells is presented. It is based on a superposition of a drift-dominated collection model and of the classical drift-diffusion transport model of the pn-diode. The model is the basis for a solar cell equivalent circuit, identical to the one introduced by Merten ...
Painter K J - - 2009
The extracellular matrix (ECM) is a highly organised structure with the capacity to direct cell migration through their tendency to follow matrix fibres, a process known as contact guidance. Amoeboid cell populations migrate in the ECM by making frequent shape changes and have minimal impact on its structure. Mesenchymal cells ...
Lee, Daniel W.
Monolithic porous ceramic and porous polystyrene microcarriers were examined as supports for large scale mammalian cell culture. Vero cells and transformed baby hamster kidney (BHK) cells which produced human transferrin were grown in three different reactor configurations: a fixed bed ceramic perfusion system, an airlift systemwith draft tube made of ...
Damiand, Guillaume
In this paper, we present an algorithm for computing efficiently homology generators of 3D subdivided orientable objects which can contain tunnels and cavities. Starting with an initial subdivision, represented with a generalized map where every cell is a topological ball, the number of cells is reduced using simplification operations (removal ...
Canić Suncica - - 2008
Auricular elastic cartilage is a potential source for lining of luminal surfaces of implantable vascular devices, such as stents and left ventricular assist devices with the purpose to improve their biocompatibility. Auricular chondrocytes are easily accessible, harvested, and isolated, and they have been shown to provide a strong adherent cell ...
Kryukov A K - - 2008
We study collective phenomena in highly heterogeneous cardiac cell culture and its models. A cardiac culture is a mixture of passive (fibroblasts), oscillatory (pacemakers), and excitable (myocytes) cells. There is also heterogeneity within each type of cell as well. Results of in vitro experiments are modelled by Luo-Rudy and FitzHugh-Nagumo ...
Huang, Jun
A KINETIC STUDY OF THE T CELL RECOGNITION MECHANISM
Stenlund Hans - - 2008
In this study, the orthogonal projections to latent structures discriminant analysis (OPLS-DA) method was used to assess the in situ chemical composition of two different cell types in mouse liver samples, hepatocytes and erythrocytes. High spatial resolution FT-IR microspectroscopy equipped with a focal plan array (FPA) detector is capable of ...
Painter Scott - - 2008
Dewatered or "dry" grid cells in the USGS ground water modeling software MODFLOW may cause nonphysical artifacts, trigger convergence failures, or interfere with parameter estimation. These difficulties can be avoided in two dimensions by modifying the spatial differencing scheme and the iterative procedure used to resolve nonlinearities. Specifically, the spatial ...
Bur Michael - - 2009
A modified Astra type multistage liquid impinger (MSLI) with integrated bronchial cell monolayers was used to study deposition and subsequent drug absorption on in vitro models of the human airway epithelial barrier. Inverted cell culture of Calu-3 cells on the bottom side of cell culture filter inserts was integrated into ...
Wenzhong Gao, Jiaxin Ning
The fuel cell is a potential alternative energy source for an electric vehicle powertrain. The wide range of frequency spectrum generated by different types of power electronic converter in the fuel cell power conditioning unit causes ripples in the current drawn from fuel cells, and thus affects fuel cell performance ...
Acevedo Cristian A - - 2009
The use of fibrin in tissue engineering has greatly increased over the last 10 years. The aim of this research was to develop a mathematical model to relate the microcapsule-size and cell-load to growth and oxygen depletion. Keratinocytes were isolated from rat skins and microencapsulated dropping fibrinogen and thrombin solutions. ...
Balasubramanian Lavanya - - 2008
Impedance of renal vascular smooth muscle cells (VSMCs) cultured on microelectrodes was measured by electric cell-substrate impedance sensing. Changes in measured impedance as a function of frequency were compared with the calculated values obtained from an extended cell-electrode model to estimate the junctional resistance, distance between the ventral cell surface ...
Shen Xiling - - 2008
A closed-loop control system drives progression of the coupled stalked and swarmer cell cycles of the bacterium Caulobacter crescentus in a near-mechanical step-like fashion. The cell-cycle control has a cyclical genetic circuit composed of four regulatory proteins with tight coupling to processive chromosome replication and cell division subsystems. We report ...
Jang Wonhee W Department of Life Science, Dongguk University, Chung-Gu, Seoul, Korea. - - 2008
Little is known about how the sizes of specific organs and tissues are regulated. To try to understand these mechanisms, we have been using a combination of modelling and experiments to study the simple system Dictyostelium discoideum, which forms approximately 20000 cell groups. We found that cells secrete a factor, ...
Shahrezaei Vahid - - 2008
Cell behaviour and the cellular environment are stochastic. Phenotypes vary across isogenic populations and in individual cells over time. Here we will argue that to understand the abilities of cells we need to understand their stochastic nature. New experimental techniques allow gene expression to be followed in single cells over ...
Feng Yusheng Y Computational Bioengineering and Nanotechnology Laboratory, Department of Mechanical Engineering, The University of Texas at San Antonio, San Antonio, TX 78249, USA. - - 2008
The ultimate goal of cancer treatment utilizing thermotherapy is to eradicate tumors and minimize damage to surrounding host tissues. To achieve this goal, it is important to develop an accurate cell damage model to characterize the population of cell death under various thermal conditions. The traditional Arrhenius model is often ...
Beck, N.
The missing correlation between film characteristics and <i>α</i>-Si:H-based <i>p-i-n</i> solar cells is still a controversial subject. The authors present a new parameter <i>µ</i><sup>0</sup><i>τ</i><sup>0</sup>, evaluated from steady-state transport measurements on <i>a</i>-Si:H layers, which can indeed relate film quality and cell performance as far as the latter is limited by the quality ...
Ahmed Tanvir - - 2008
We present novel microfluidic experiments to quantify population-scale transport parameters (chemotactic sensitivity chi(0) and random motility mu) of a population of bacteria. Previously, transport parameters have been derived theoretically from single-cell swimming behavior using probabilistic models, yet the mechanistic foundations of this upscaling process have not been verified experimentally. We ...
Pawar Parag - - 2008
Polymorphonuclear leukocyte (PMN) recruitment to sites of inflammation is initiated by selectin-mediated PMN tethering and rolling on activated endothelium under flow. Cell rolling is modulated by bulk cell deformation (mesoscale), microvillus deformability (microscale), and receptor-ligand binding kinetics (nanoscale). Selectin-ligand bonds exhibit a catch-slip bond behavior, and their dissociation is governed ...
Rosenfeld, D.
The dynamic structure of the atmospheric marine boundary layer (MBL) supports two distinct states of cloud cover: closed and open Benard cellular convection. Closed cells are nearly fully cloud covered, while the open cells have <40% cloud cover. Here we show that aerosols have a greater than expected impact on ...
Deguchi Shinji - - 2009
Previous studies on the intracellular force balance that forms the adherent cell structure have paid much attention to the mechanical behavior of cells seen in the horizontal project plane. By contrast, there are only few quantitative considerations on that in the vertical plane. Particularly, the contribution of the nucleus to ...
Itoh, Takayuki
This article presents a computational method for generating organic textures. The method first tessellates a region into a set of pseudo-Voronoi polygons using a particle model and then generates the detailed geometry of each of the polygons using Loop's subdivision surface with fractal noise. Unlike previous particle models-which are designed ...
Rebora, N.
Rain cells are structures which represent an important component of convective precipitation and a study of their properties represents a necessary step both towards improved stochastic models of small-scale precipitation and for the verification of deterministic high resolution local-area models. The case of intense convective precipitation in the tropics has ...
Yasuhiro Naito
Keywords: E-Cell, Kyoto model, cell simulation, ion channel
Awazu Akinori - - 2008
Dynamical aspects of the asymmetric cellular automata were investigated to consider the signaling processes in biological systems. As a meta-model of the cascade of feed-forward loop type network motifs in biological reaction networks, we consider the one dimensional asymmetric cellular automata where the state of each cell is controlled by ...
Kepseu W D - - 2008
In this paper, numerical simulation of calcium waves in a network of cells coupled together by a paracrine signaling is investigated. The model takes into account the long-range interaction between cells due to the action of extracellular messengers, which provide links between first-neighbor cells, but also on cells located far ...
Bansaye, Vincent
We consider a branching model introduced by Kimmel for cell division with parasite infection. Cells contain proliferating parasites which are shared randomly between the two daughter cells when they divide. We determine the probability that the organism recovers, meaning that the asymptotic proportion of contaminated cells vanishes. We study the ...
Jong-O Lee, Johanna Rosenfield, ...
Since BoNTs are potential biothreat agents, efforts are being made to develop therapeutic countermeasures for which sensitive in vitro models are required to evaluate the efficacy of potential therapeutic agents. In this report, we tested human neuroblastoma cell lines for their susceptibility to BoNT toxicity and demonstrated the application of ...
Belmonte Julio M - - 2008
A self-propelled particle model is introduced to study cell sorting occurring in some living organisms. This allows us to evaluate the influence of intrinsic cell motility separately from differential adhesion with fluctuations, a mechanism previously shown to be sufficient to explain a variety of cell rearrangement processes. We find that ...
Chavoya Arturo - - 2008
Cell pattern generation has a fundamental role in both artificial and natural development. This paper presents results from a model in which a genetic algorithm (GA) was used to evolve an artificial regulatory network (ARN) to produce predefined 2D cell patterns through the selective activation and inhibition of genes. The ...
Zhang, Jihui
Cell sectorization is a promising method for improving the capacity of code division multiple access (CDMA) systems. It has been shown that the use of adaptive antenna arrays with dynamic cell sectoring is particularly suitable for non-uniformly distributed users. In this paper, we present a novel Cluster-based sectoring algorithm for ...
Debeir Olivier - - 2008
In vitro cell imaging is a useful exploratory tool for cell behavior monitoring with a wide range of applications in cell biology and pharmacology. Combined with appropriate image analysis techniques, this approach has been shown to provide useful information on the detection and dynamic analysis of cell events. In this ...
Edd Jon F - - 2008
Encapsulation of cells within picolitre-size monodisperse drops provides new means to perform quantitative biological studies on a single-cell basis for large cell populations. Variability in the number of cells per drop due to stochastic cell loading is a major barrier to these techniques. We overcome this limitation by evenly spacing ...
Bouyer Daniel - - 2008
Trichome patterning in Arabidopsis serves as a model system to study how single cells are selected within a field of initially equivalent cells. Current models explain this pattern by an activator-inhibitor feedback loop. Here, we report that also a newly discovered mechanism is involved by which patterning is governed by ...
Bansaye, Vincent
We consider a branching model introduced by Kimmel for cell division with parasite infection. Cells contain proliferating parasites which are shared randomly between the two daughter cells when they divide. We determine the probability that the organism recovers, meaning that the asymptotic proportion of contaminated cells vanishes. We study the ...
Henneman S - - 2008
This review describes the mechanical and biological signalling pathways during orthodontic tooth movement and provides an update of the current literature. A theoretical model is introduced to elucidate the complex cascade of events after the application of an orthodontic force to a tooth. In this model, the events are divided ...
Chen Hsiu-Hung - - 2008
Light microscopy method offers unique abilities for the determination of membrane transport properties of either single or multiple cells. A stream imaging system composed of a microfluidic device, a charge-coupled device camera, and a microscope has been developed to study the osmotic behavior of multiple cells in response toward their ...
Holmes Raquell M - - 2008
Through live cell imaging and computational modeling, Neves et al. (2008) demonstrate that molecular interactions alone are insufficient to explain the patterns of MAPK activation: a model must include the cell morphology and spatial distribution of signaling molecules.
Zeng Yan - - 2008
Micropatterning of two different cell types based on surface modification allows spatial control over two distinct cell subpopulations. This study considers a micropatterned coculture system, which has release and absorption parts alternately arranged at the base, and each part has a single cell type. A micropattern unit was defined and ...
Rahman A R A - - 2008
We report on the impedance mapping of in vitro cellular morphology by electrical impedance spectroscopy, using microelectrodes. A micro multielectrode system was designed, fabricated, assembled, tested and demonstrated for the monitoring of anchorage-dependent cell behavior and morphology. This system allowed continuous, label-free, quantitative monitoring and visualization of cell adhesion, spreading, ...
Krzyzanski Wojciech - - 2008
A new class of basic indirect pharmacodynamic models for agents that alter the loss of natural cells based on a lifespan concept are presented. The lifespan indirect response (LIDR) models assume that cells (R) are produced at a constant rate (k(in)), survive during a certain duration T(R), and finally are ...
Pappu Vijay - - 2008
Three-dimensional computational modeling and simulation are presented on the adhesive rolling of deformable leukocytes over a P-selectin coated surface in parabolic shear flow in microchannels. The computational model is based on the immersed boundary method for cell deformation and Monte Carlo simulation for receptor/ligand interaction. The simulations are continued for ...
Eyiyurekli Manolya - - 2008
We present a computational model that successfully captures the cell behaviors that play important roles in 2-D cell aggregation. A virtual cell in our model is designed as an independent, discrete unit with a set of parameters and actions. Each cell is defined by its location, size, rates of chemoattractant ...
Leon-Quinto Trinidad - - 2009
This work presents a Biological Resource Bank generated as a complementary supporting tool for the reproduction and the in situ and ex situ conservation of the Iberian lynx. In its design we prioritized the preservation of a maximum of the current genetic and biological diversity of the population, and the ...
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