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Causin, Paola; Mathematics, University ...
In the embryo, undifferentiated sets of cells form organized patterns following pathways marked by chemical cues, like ''Little Tom Thumbs'' of the molecular world. At this small scale, cues are represented by single molecules, displaced from their release location by diffusion. Diffusion is the movement of matter from areas with ...
Zhao Hongsheng - - 2008
A computer program, QtUCP, has been developed based on several well-established algorithms using GCC 4.0 and Qt 4.0 (Open Source Edition) under Debian GNU/Linux 4.0r0. It can determine the unit-cell parameters from an electron diffraction tilt series obtained from both double-tilt and rotation-tilt holders. In this approach, two or more ...
Féréol Sophie - - 2008
Cell mechanics provides an integrated view of many biological phenomena which are intimately related to cell structure and function. Because breathing constitutes a sustained motion synonymous with life, pulmonary cells are normally designed to support permanent cyclic stretch without breaking, while receiving mechanical cues from their environment. The authors study ...
Jin Songwan - - 2008
Diffusion through the extracellular space (ECS) in brain is important in drug delivery, intercellular communication, and extracellular ionic buffering. The ECS comprises approximately 20% of brain parenchymal volume and contains cell-cell gaps approximately 50 nm. We developed a random-walk model to simulate macromolecule diffusion in brain ECS in three dimensions ...
Rempe Michael J MJ Department of Applied Mathematics, Northwestern University, Evanston, IL 60208, - - 2008
Since their inception, computational models have become increasingly complex and useful counterparts to laboratory experiments within the field of neuroscience. Today several software programs exist to solve the underlying mathematical system of equations, but such programs typically solve these equations in all parts of a cell (or network of cells) ...
Falou Omar - - 2008
High-frequency ultrasound is a novel method to detect cell death based on changes in cell morphology that cause alterations in the acoustic properties of cell ensembles in tissues. In previous work, our group has suggested that for cells with a nucleus to cell volume ratio of 0.33, the backscatter response ...
Wikström J - - 2008
BACKGROUND: In cell therapy, microencapsulated cells secrete therapeutic protein, which is further released from the microcapsules. In principle, some secreted, but unreleased, protein may accumulate in the microcapsules. The kinetic simulation model was built to simulate the potential accumulation of the protein in the microcapsules. METHODS: The alginate microcapsules were ...
Kolios Michael C - - 2008
The goal of ultrasonic tissue characterization is to extract information over and above the information conventionally displayed on imaging instruments which is typically the backscatter strength (B-mode image). The driving hypothesis of our work is that as the ultrasound wavelength approaches the size of a cell, the backscatter characteristics become ...
Gunji Yukio-Pegio - - 2008
A cell is a minimal self-sustaining system that can move and compute. Previous work has shown that a unicellular slime mold, Physarum, can be utilized as a biological computer based on cytoplasmic flow encapsulated by a membrane. Although the interplay between the modification of the boundary of a cell and ...
Korn R W - - 2008
OBJECTIVES: Extensive mathematical studies have been made on cell clone development but little has been advanced in the mathematics of small clone formation and virtually no actual data of small clone size has been collected. MATERIALS AND METHODS: Small clone sizes in leaf marginal cells of the aquatic plant Elodea ...
Nakajima Akihiko - - 2008
In multicellular organisms, several cell states coexist. For determining each cell type, cell-cell interactions are often essential, in addition to intracellular gene expression dynamics. Based on dynamical systems theory, we propose a mechanism for cell differentiation with regulation of populations of each cell type by taking simple cell models with ...
Hoffman A - - 2008
A previously described model for cellular proliferation, based on the relationship of the cell cycle to redox parameters, is explored here to account for the origin of the cancerous cell and some of its key abnormal characteristics, such as the Warburg effect, apoptosis, aneuploidy, and uncontrolled proliferation. We describe how ...
Regnault, Damien
Cellular automata have been mainly studied on very regular graphs carrying the cells (like lines or grids) and under synchronous dynamics (all cells update simultaneously). In this paper we study how the asynchronism and the topology of cells act upon the dynamics of the classical Minority rule. Beyond its apparent ...
Zhou, Jie
The demand for wireless mobile communications has grown at a very high rate, recently. In order to solve the non-uniform traffic rates, the use of cell splits is unavoidable for balancing the traffic rate and maximizing total system capacity. For cell planning, a DS-CDMA cellular system can be comprise of ...
Manbachi Amir A Harvard-MIT Division of Health Sciences and Technology, Massachusetts Institute of Technology, 65 Landsdowne Street, Room 252, Cambridge, MA 02139, - - 2008
Immobilization of cells inside microfluidic devices is a promising approach for enabling studies related to drug screening and cell biology. Despite extensive studies in using grooved substrates for immobilizing cells inside channels, a systematic study of the effects of various parameters that influence cell docking and retention within grooved substrates ...
Galle J - - 2009
Collective phenomena in multi-cellular assemblies can be approached on different levels of complexity. Here, we discuss a number of mathematical models which consider the dynamics of each individual cell, so-called agent-based or individual-based models (IBMs). As a special feature, these models allow to account for intracellular decision processes which are ...
Su, Jing
High-throughput cell culture is an emerging technology that shows promise as a tool for research in tissue engineering, drug discovery, and medical diagnostics. An important, but overlooked, challenge is the integration of experimental methods with information processing suitable for handling large databases of cell-cell and cell-substrate interactions. In this work ...
Franck Carl - - 2008
In cell culture, when cells are inoculated into fresh media, there can be a period of slow (or lag phase) growth followed by a transition to exponential growth. This period of slow growth is usually attributed to the cells' adaptation to a new environment. However, we argue that, based on ...
Kasperski Andrzej - - 2008
This paper presents an integrated model describing the control of Saccharomyces cerevisiae yeast cells bioenergetics. This model describes the oxidative and respirofermentative metabolism. The model assumes that the mitochondria of the Saccharomyces cerevisiae cells are charged with NADH during the tricarboxylic acid cycle, and NADH is discharged from mitochondria later ...
Eblin K E - - 2008
Arsenical-induced carcinogenesis in human bladder has been established through epidemiological evidence, and UROtsa cells, a normal, immortalized cell culture model of human urothelium, have proven to be a good model for the bladder epithelium. This cell line does not form tumors when injected into immuno-compromised mice nor does it have ...
Nakielski Jerzy - - 2008
Plant organs grow symplastically, i.e. in a continuous and coordinated way. Such growth is of a tensor nature, which is manifested in the property that at every point of the organ three mutually orthogonal principal growth directions (PDG) can be recognized. The PDGs are postulated to affect orientation of cell ...
Briegel Ariane A Division of Biology, California Institute of Technology, 1200 E. California Blvd., Pasadena, CA 91125, - - 2008
A new method for recording both fluorescence and cryo-EM images of small bacterial cells was developed and used to identify chemoreceptor arrays in cryotomograms of intact Caulobacter crescentus cells. We show that in wild-type cells preserved in a near-native state, the chemoreceptors are hexagonally packed with a lattice spacing of ...
Belfiore Laurence A - - 2008
The theory of heterogeneous catalysis in chemical reactors is employed to simulate laminar flow through tubes at large mass transfer Peclet numbers in which anchorage-dependent cells (i) adhere to a protein coating on the inner surface at r=R(wall), (ii) receive nutrients and oxygen from an aqueous medium via transverse diffusion ...
Tozaki Hirokazu - - 2008
Single-cell-level behaviors of cells are typically inferred from ensemble measurements. However, such inferences implicitly assume a biological version of ergodicity: the percentage of cells in a state is identical to the probability to find a cell in that state. While the ergodicity does not always hold, it has been rarely ...
Araújo N A M - - 2008
We study the effect of the presence of a regular substrate pattern on the irreversible adsorption of nanosized and colloid particles. Deposition of disks of radius r(0) is considered, with the allowed regions for their center attachment at the planar surface consisting of square cells arranged in a square lattice ...
Xu Min - - 2008
A unified Mie and fractal model for light scattering by biological cells is presented. This model is shown to provide an excellent global agreement with the angular dependent elastic light scattering spectroscopy of cells over the whole visible range (400 to 700 nm) and at all scattering angles (1.1 to ...
Klein Allon M AM Cavendish Laboratory, Madingley Road, Cambridge CB3 OHE, United - - 2008
The dynamics of a genetically labeled cell population may be used to infer the laws of cell division in mammalian tissue. Recently, we showed that in mouse tail skin, where proliferating cells are confined to a two-dimensional layer, cells proliferate and differentiate according to a simple stochastic model of cell ...
Khan Adil G - - 2008
Many species of mammals are very good at categorizing odors. One model for how this is achieved involves the formation of "attractor" states in the olfactory processing pathway, which converge to stable representations for the odor. We analyzed the responses of rat olfactory bulb mitral/tufted (M/T) cells using stimuli "morphing" ...
Wong Amy P AP Harvard Biophysics Program, Harvard Medical School, Boston, MA 02115, - - 2008
Accurate modeling of the cellular microenvironment is important for improving studies of cell biology in vitro. Here, we demonstrate a flexible method for creating a cellular microenvironment in vitro that allows (i) controlled spatial distribution (patterning) of multiple types of cells within three-dimensional (3-D) matrices of a biologically derived, thermally ...
Tomelleri C - - 2008
OBJECTIVES: In this study, we quantify growth variability of tumour cell clones from a human leukaemia cell line. MATERIALS AND METHODS: We have used microplate spectrophotometry to measure growth kinetics of hundreds of individual cell clones from the Molt3 cell line. Growth rate of each clonal population has been estimated ...
Zajac Mark - - 2008
Cell crawling is an inherently physical process that includes protrusion of the leading edge, adhesion to the substrate, and advance of the trailing cell body. Research into advance of the cell body has focused on actomyosin contraction, with cytoskeletal disassembly regarded as incidental, rather than causative; however, extracts from nematode ...
Currie, David
This work concerns the modelling of the dielectric properties of biological cell suspensions. The relative permittivity of a suspension is proportional to the volume fraction of suspended cells but it would be more useful to know the average cell radius and number density separately. A non-linear least squares algorithm, based ...
Hines Michael L ML Computer Science, Yale University, New Haven, CT, USA. - - 2008
Neuron tree topology equations can be split into two subtrees and solved on different processors with no change in accuracy, stability, or computational effort; communication costs involve only sending and receiving two double precision values by each subtree at each time step. Splitting cells is useful in attaining load balance ...
Wang, Yang
My dissertation researches are on the field of fuel cell materials and fuel cell modeling. During my dissertation research, I authored two US patent applications and have developed several innovative approaches to new fuel cell materials, novel fuel cell hybrid power device and an original fuel cell modeling method. A ...
Biktashev Vadim N VN Department of Mathematical Sciences, University of Liverpool, Liverpool L69 7ZL, United - - 2008
We aim to understand the formation of abnormal waves of activity from myocardial regions with diminished cell-to-cell coupling. En route to this goal, we studied the behavior of a heterogeneous myocyte network in which a sharp coupling gradient was placed under conditions of increasing network automaticity. Experiments were conducted in ...
Wurdinger Thomas T Molecular Neurogenetics Unit, Department of Neurology, Harvard Medical School, 149 13th St., Charlestown, Massachusetts 02129, - - 2008
Luciferases are widely used to monitor biological processes. Here we describe the naturally secreted Gaussia princeps luciferase (Gluc) as a highly sensitive reporter for quantitative assessment of cells in vivo by measuring its concentration in blood. The Gluc blood assay complements in vivo bioluminescence imaging, which has the ability to ...
Fernandez-Capetillo Oscar - - 2008
In response to DNA double-stranded breaks (DSBs) cells activate a signaling cascade known as the DNA damage response (DDR) whose main function is to promote the repair of the lesions while it delays cell cycle progression until repair is completed. Whereas most cells respond alike to an equivalent dose of ...
Satulovsky Javier J Department of Physiology, University of Massachusetts Medical School, Worcester, Massachusetts 01605, - - 2008
We have developed a top-down, rule-based mathematical model to explore the basic principles that coordinate mechanochemical events during animal cell migration, particularly the local-stimulation-global-inhibition model suggested originally for chemotaxis. Cells were modeled as a shape machine that protrudes or retracts in response to a combination of local protrusion and global ...
Mtibaa Riadh - - 2008
We propose a computational model of perceptual grouping for explaining the 3D shape representation of an illusory percept called "mime effect." This effect is associated with the generation of an illusory, volumetric perception that can be induced by particular distributions of inducing stimuli such as cones, whose orientations affect the ...
Rejniak Katarzyna A KA Division of Mathematics, University of Dundee, Dundee, DD1 4HN, Scotland, UK. - - 2008
Normal hollow epithelial acini are 3-dimensional culture structures that resemble the architecture and functions of normal breast glands and lobules. This experimental model enables in vitro investigations of genotypic and molecular abnormalities associated with epithelial cancers. However, the way in which the acinar structure is formed is not yet completely ...
Dieterich Peter - - 2008
Cell movement--for example, during embryogenesis or tumor metastasis--is a complex dynamical process resulting from an intricate interplay of multiple components of the cellular migration machinery. At first sight, the paths of migrating cells resemble those of thermally driven Brownian particles. However, cell migration is an active biological process putting a ...
J. Holis
This paper deals with the application of High Altitude Platforms for the provision of third generation mobile services in sparsely-populated areas or in developing countries. It focuses on the behavior of large cells provided via a multiple HAP deployment and shows the possibilities of using small cells located inside these ...
Sokalski, Tomasz
Fuel Cells Science and Technology 2008, Scientific Advances in Fuel Cell Systems, Copenhagen, 8-9 October, 2008
Philipps, S.P.
In this letter a calibrated numerical model of a III-V dualjunction solar cell including tunnel diode and Bragg reflector is presented. The quantum efficiencies of the subcells are computed by using the principle of current-limitation in monolithic multi-junction solar cells. A special procedure with bias-illumination and bias-voltage was implemented. Numerical ...
Fisher, Jasmin
We introduce bounded asynchrony, a notion of concurrency tailored to the modeling of biological cell-cell interactions. Bounded asynchrony is the result of a scheduler that bounds the number of steps that one process gets ahead of other processes; this allows the components of a system to move independently while keeping ...
Pflug, A.
Parallel plate reactors for plasma activated chemical vapor deposition (PACVD) of a-Si:H/µc-Si:H are an established technology for the fabrication of thin film solar cells based on a-Si:H as well as a-Si:H/µc-Si:H tandem solar cells. In solar cell fabrication lines, a high deposition rate and a rate homogeneity better than 5% ...
Sandersius Sebastian A - - 2008
Recently, the Subcellular Element Model (SEM) has been introduced, primarily to compute the dynamics of large numbers of three-dimensional deformable cells in multicellular systems. Within this model framework, each cell is represented by a collection of elastically coupled elements, interacting with one another via short-range potentials, and dynamically updated using ...
Hatzikirou Haralambos - - 2008
Understanding the precise interplay of moving cells with their typically heterogeneous environment is crucial for central biological processes as embryonic morphogenesis, wound healing, immune reactions or tumor growth. Mathematical models allow for the analysis of cell migration strategies involving complex feedback mechanisms between the cells and their microenvironment. Here, we ...
Yang Liu - - 2008
BACKGROUND: Many cellular processes involve substantial shape changes. Traditional simulations of these cell shape changes require that grids and boundaries be moved as the cell's shape evolves. Here we demonstrate that accurate cell shape changes can be recreated using level set methods (LSM), in which the cellular shape is defined ...
Möhler Lars - - 2008
To describe the growth behavior of anchorage-dependent mammalian cells in microcarrier systems, various approaches comprising deterministic and stochastic single cell models as well as automaton-based models have been presented in the past. The growth restriction of these often contact-inhibited cells by spatial effects is described at levels with different complexity ...
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