Search Results
Results 201 - 250 of 1912
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Bousis C - - 2010
A hybrid Monte Carlo transport scheme combining event-by-event and condensed-history simulation with a full account of energy-loss straggling was used to study the dosimetric characteristics of the Auger-emitting radionuclides 67Ga, 99mTc, 111In, 123I, 125I and 201Tl at the single-cell level. The influence of the intracellular localization of the Auger radionuclide ...
Kim Pan-Jun - - 2010
Genetically identical cells under the same environmental conditions can show strong variations in protein copy numbers due to inherently stochastic events in individual cells. We here develop a theoretical framework to address how variations in enzyme abundance affect the collective kinetics of metabolic reactions observed within a population of cells. ...
Bloomfield J M - - 2010
Mosaic tissues are composed of two or more genetically distinct cell types. They occur naturally, and are also a useful experimental method for exploring tissue growth and maintenance. By marking the different cell types, one can study the patterns formed by proliferation, renewal and migration. Here, we present mathematical modelling ...
Cencic Avrelija - - 2010
Animal experimentation has a long tradition for risk assessment of new drugs before they reach the clinic. To reduce expensive animal experimentation, attempts have been made to build inexpensive and convenient intestinal functional cell models to study toxicity and bioavailability of new substances along with providing relevant models to study ...
Calmelet Colette - - 2010
In this paper we discuss a model of zebrafish embryo notochord development based on the effect of surface tension of cells at the boundaries. We study the process of interaction of mesodermal cells at the boundaries due to adhesion and cortical tension, resulting in cellular intercalation. From in vivo experiments, ...
Liang Shufang - - 2010
Honokiol (HNK), a natural small molecular product, inhibited proliferation of HepG2 cells and exhibited anti-tumor activity in nude mice. In this article, we applied a novel sensitive stable isotope labeling with amino acids in cell culture-based quantitative proteomic method and a model of nude mice to investigate the correlation between ...
Brown M Rowan MR School of Medicine, Cardiff University, Cardiff, United Kingdom. - - 2010
We present a new approach to the handling and interrogating of large flow cytometry data where cell status and function can be described, at the population level, by global descriptors such as distribution mean or co-efficient of variation experimental data. Here we link the "real" data to initialise a computer ...
Jabbari Sara - - 2011
Bacillus subtilis cells may opt to forgo normal cell division and instead form spores if subjected to certain environmental stimuli, for example nutrient deficiency or extreme temperature. The resulting spores are extremely resilient and can survive for extensive periods of time, importantly under particularly harsh conditions such as those mentioned ...
Li Bo - - 2010
Experimental investigations of cell size control in fission yeast Schizosaccharomyces pombe have illustrated that the cell cycle features 'sizer' and 'timer' phases which are distinguished by a growth rate changing point. Based on current biological knowledge of fission yeast size control, we propose here a model of ordinary differential equations ...
Roy Sitikantha - - 2010
Cell locomotion is a result of a series of synchronized chemo-mechanical processes. Previous extensive experimental studies have revealed many chemo-mechanical processes that may contribute to cell locomotion. In parallel, theoretical works have been developed to provide deeper insight. To date, however, direct simulations of cell locomotion on a substrate have ...
Ma Yanping - - 2010
Our research focused on the polymorphonuclear neutrophils (PMNs) tethering to the vascular endothelial cells (EC) and the subsequent melanoma cell emboli formation in a shear flow, an important process of tumor cell extravasation from the circulation during metastasis. We applied population balance model based on Smoluchowski coagulation equation to study ...
Zeiger Lisa - - 2010
The potential of facultative photosynthetic bacteria as producers of photosynthetic pigments, vitamins, coenzymes and other valuable products has been recognized for decades. However, mass cultivation under photosynthetic conditions is generally inefficient due to the inevitable limitation of light supply when cell densities become very high. The previous development of a ...
Nadell Carey D - - 2010
On its own, a single cell cannot exert more than a microscopic influence on its immediate surroundings. However, via strength in numbers and the expression of cooperative phenotypes, such cells can enormously impact their environments. Simple cooperative phenotypes appear to abound in the microbial world, but explaining their evolution is ...
Uriu Koichiro - - 2010
In vertebrate somitogenesis, the expression of segmentation clock genes oscillates and the oscillation is synchronized over nearby cells. Both experimental and theoretical studies have shown that the synchronization among cells is realized by intercellular interaction via Delta-Notch signaling. However, the following questions emerge: (i) During somitogenesis, dynamic rearrangement of relative ...
Slomka Noa - - 2010
This study introduces a new confocal microscopy-based three-dimensional cell-specific finite element (FE) modeling methodology for simulating cellular mechanics experiments involving large cell deformations. Three-dimensional FE models of undifferentiated skeletal muscle cells were developed by scanning C2C12 myoblasts using a confocal microscope, and then building FE model geometries from the z-stack ...
Dunlop Mary J - - 2010
Cells use feedback to implement a diverse range of regulatory functions. Building synthetic feedback control systems may yield insight into the roles that feedback can play in regulation since it can be introduced independently of native regulation, and alternative control architectures can be compared. We propose a model for microbial ...
Zhou E H - - 2010
Accurate quantification of the mechanical properties of living cells requires the combined use of experimental techniques and theoretical models. In this paper, we investigate the viscoelastic response of suspended NIH 3T3 fibroblasts undergoing micropipette aspiration using power-law rheology model. As an important first step, we examine the pipette size effect ...
Gandolfi Alberto - - 2011
We propose a model with age and space structure for the evolution of the supra-basal epidermis. The model includes different types of cells: proliferating cells, differentiated cells, corneous cells, and apoptotic cells. We assume that all cells move with the same velocity and that the local volume fraction, occupied by ...
Shirazi-Adl A - - 2010
Responsible for making and maintaining the extracellular matrix, the cells of intervertebral discs are supplied with essential nutrients by diffusion from the blood supply through mainly the cartilaginous endplates (CEPs) and disc tissue. Decrease in transport rate and increase in cellular activity may adversely disturb the intricate supply-demand balance leading ...
Park Chan Young CY Dept. of Environmental Health, Harvard School of Public Health, Boston, MA 02115, - - 2010
Cell mechanical properties on a whole cell basis have been widely studied, whereas local intracellular variations have been less well characterized and are poorly understood. To fill this gap, here we provide detailed intracellular maps of regional cytoskeleton (CSK) stiffness, loss tangent, and rate of structural rearrangements, as well as ...
Cairo Christopher W CW Department of Chemistry and Alberta Ingenuity Centre for Carbohydrate Science, University of Alberta, Edmonton, Alberta T6G 2G2, Canada. - - 2010
The leukocyte common antigen, CD45, is a critical immune regulator whose activity is modulated by cytoskeletal interactions. Components of the spectrin-ankyrin cytoskeleton have been implicated in the trafficking and signaling of CD45. We have examined the lateral mobility of CD45 in resting and activated T lymphocytes using single-particle tracking and ...
Lesman Ayelet - - 2010
Novel tissue-culture bioreactors employ flow-induced shear stress as a means of mechanical stimulation of cells. We developed a computational fluid dynamics model of the complex three-dimensional (3D) microstructure of a porous scaffold incubated in a direct perfusion bioreactor. Our model was designed to predict high shear-stress values within the physiological ...
Xu Mingen - - 2010
One of the major obstacles in drug discovery is the lack of in vitro three-dimensional (3D) models that can capture more complex features of a disease.Here we established a in vitro physiological model of the metabolic syndrome (MS) using cell-assembly technique (CAT), which can assemble cells into designated places to ...
Cai Zhongli - - 2010
Our objective was to compare Monte Carlo N-particle (MCNP) self- and cross-doses from (111)In to the nucleus of breast cancer cells with doses calculated by reported analytic methods (Goddu et al. and Farragi et al.). A further objective was to determine whether the MCNP-predicted surviving fraction (SF) of breast cancer ...
Cao Guoxin - - 2010
Viscoelastic mechanical properties of biological cells are commonly measured using atomic force microscope (AFM) dynamic indentation with spherical tips. A semiempirical analysis based on numerical simulation is built to determine the cell mechanical properties. It is shown that the existing analysis cannot reflect the accurate values of cell elastic/dynamic modulus ...
Aegerter-Wilmsen Tinri - - 2010
Apical cell surfaces in metazoan epithelia, such as the wing disc of Drosophila, resemble polygons with different numbers of neighboring cells. The distribution of these polygon numbers has been shown to be conserved. Revealing the mechanisms that lead to this topology might yield insights into how the structural integrity of ...
Bertaud Jérémie - - 2010
The cell's cytoskeleton, providing cells with structure and shape, consists of different structural proteins, including microtubules, actin microfilaments and intermediate filaments. It has been suggested that intermediate filaments play a crucial role in providing mechanical stability to cells. By utilizing a simple coarse-grained computational model of the intermediate filament network ...
Friedl Peter - - 2010
Cell migration underlies tissue formation, maintenance, and regeneration as well as pathological conditions such as cancer invasion. Structural and molecular determinants of both tissue environment and cell behavior define whether cells migrate individually (through amoeboid or mesenchymal modes) or collectively. Using a multiparameter tuning model, we describe how dimension, density, ...
Bock Martin - - 2010
Voronoi tessellations have been used to model the geometric arrangement of cells in morphogenetic or cancerous tissues, however, so far only with flat hyper-surfaces as cell-cell contact borders. In order to reproduce the experimentally observed piecewise spherical boundary shapes, we develop a consistent theoretical framework of multiplicatively weighted distance functions, ...
Fletcher Sarah J - - 2010
Polarised vesicle trafficking has been suggested to regulate cell migration. Understanding how this takes place has been complicated by the use of disparate assays and cellular models. Although polarised trafficking does occur in cell motility it is not clear which pathways are involved. We propose a model for migrating cells ...
Chen Wen Li Kelly - - 2010
Cell-substrate interactions are multifaceted, involving the integration of various physical and biochemical signals. The interactions among these microenvironmental factors cannot be facilely elucidated and quantified by conventional experimentation, and necessitate multifactorial strategies. Here we describe an approach that integrates statistical design and analysis of experiments with automated microscopy to systematically ...
Jeon Junhwan - - 2010
We have developed an off-lattice hybrid discrete-continuum (OLHDC) model of tumor growth and invasion. The continuum part of the OLHDC model describes microenvironmental components such as matrix-degrading enzymes, nutrients or oxygen, and extracellular matrix (ECM) concentrations, whereas the discrete portion represents individual cell behavior such as cell cycle, cell-cell, and ...
Champion Patrick D - - 2010
Monoclonal B-cell lymphocytosis (MBL) is defined by the presence of monoclonal B-cells in peripheral blood in the absence of hematologic disease. MBL is detected by flow cytometry with increasing frequency as the number of B-cells acquired increases. Computer simulations in R language were used to examine the impact of increasing ...
El-Manzalawy Yasser - - 2010
Identification of epitopes that invoke strong responses from B-cells is one of the key steps in designing effective vaccines against pathogens. Because experimental determination of epitopes is expensive in terms of cost, time, and effort involved, there is an urgent need for computational methods for reliable identification of B-cell epitopes. ...
Bowers Jeffrey S - - 2010
Replies to the comments by Plaut and McClelland and Quian Quiroga and Kreiman on the authors original article both challenged my characterization of localist and distributed representations. They also challenged the biological plausibility of grandmother cells on conceptual and empirical grounds. This reply addresses these issues in turn. The premise ...
Van Liedekerke P - - 2010
This paper is concerned with addressing how plant tissue mechanics is related to the micromechanics of cells. To this end, we propose a mesh-free particle method to simulate the mechanics of both individual plant cells (parenchyma) and cell aggregates in response to external stresses. The model considers two important features ...
Bogle Gib - - 2010
Activation of T cells by antigen-presenting cells (APCs) in lymph nodes (LNs) is a key initiating event in many immune responses. Our understanding of this process has been both improved and complicated in recent years by evidence from techniques such as intravital microscopy that has revealed new levels of dynamism ...
Janowski Sebastian - - 2010
The understanding of the molecular mechanism of cell-to-cell communication is fundamental for system biology. Up to now, the main objectives of bioinformatics have been reconstruction, modeling and analysis of metabolic, regulatory and signaling processes, based on data generated from high-throughput technologies. Cell-to-cell communication or quorum sensing (QS), the use of ...
De Wever Olivier - - 2010
Tumor invasion is the outcome of a complex interplay between cancer cells and the stromal environment. Considering the contribution of the stromal environment, we developed a membrane-free single-cell and spheroid based complementary model to study cancer invasion through native collagen type-I matrices. Cell morphology is preserved during the assays allowing ...
Tayi Venkata S - - 2010
A quantitative understanding of the process of retrovirus-mediated gene transfer into mammalian cells should assist the design and optimization of transduction protocols. We present a mathematical model of the process that incorporates the essential rate-limiting transduction steps including diffusion, convection and decay of viral vectors, their binding at the cell ...
Koziol Uriel - - 2010
In free-living flatworms somatic differentiated cells do not divide, and a separate population of stem cells (called neoblasts) is responsible for cell proliferation and renewal. In cestodes, there is evidence that similar mechanisms of cell renewal exist. In this work, we have characterized proliferative cells during the development of the ...
Janowski Miroslaw - - 2010
The last decade has been marked by a growing interest in an employment of intravenous cell delivery for treatment of neurological disorders. Numerous preclinical experimental studies have reported functional benefits, and have recently been followed by clinical trials. Some early clinical studies have indicated only modest positive effects, suggesting that ...
Kaivosoja Emilia - - 2010
Micro-textured biomaterials might enhance cytocompatibility of silicon-based micro-electro-mechanical system (bio-MEMS) dummies. Photolithography-physical vapour deposition was used to produce diamond-like carbon (DLC) or Ti squares and circles on silicon, and also their inverse replicas; then DLC and Ti were compared for their guiding potential, using a SaOS-2 cell model. Scanning electron ...
Han Ju - - 2010
Cell membrane proteins play an important role in tissue architecture and cell-cell communication. We hypothesize that segmentation and multidimensional characterization of the distribution of cell membrane proteins, on a cell-by-cell basis, enable improved classification of treatment groups and identify important characteristics that can otherwise be hidden. We have developed a ...
Rejniak Katarzyna A - - 2010
Most tumors arise from epithelial tissues, such as mammary glands and lobules, and their initiation is associated with the disruption of a finely defined epithelial architecture. Progression from intraductal to invasive tumors is related to genetic mutations that occur at a subcellular level but manifest themselves as functional and morphological ...
Jamali Yousef - - 2010
Understanding the biomechanical properties and the effect of biomechanical force on epithelial cells is key to understanding how epithelial cells form uniquely shaped structures in two or three-dimensional space. Nevertheless, with the limitations and challenges posed by biological experiments at this scale, it becomes advantageous to use mathematical and 'in ...
Thalhauser Craig J - - 2010
We study the selection dynamics in a heterogeneous spatial colony of cells. We use two spatial generalizations of the Moran process, which include cell divisions, death and migration. In the first model, migration is included explicitly as movement to a proximal location. In the second, migration is implicit, through the ...
Cselenyák Attila - - 2010
Bone marrow derived mesenchymal stem cells (MSCs) are promising candidates for cell based therapies in myocardial infarction. However, the exact underlying cellular mechanisms are still not fully understood. Our aim was to explore the possible role of direct cell-to-cell interaction between ischemic H9c2 cardiomyoblasts and normal MSCs. Using an in ...
Naldi Aurélien - - 2010
Alternative cell differentiation pathways are believed to arise from the concerted action of signalling pathways and transcriptional regulatory networks. However, the prediction of mammalian cell differentiation from the knowledge of the presence of specific signals and transcriptional factors is still a daunting challenge. In this respect, the vertebrate hematopoietic system, ...
Van Haastert Peter J M - - 2010
Cell migration in the absence of external cues is well described by a correlated random walk. Most single cells move by extending protrusions called pseudopodia. To deduce how cells walk, we have analyzed the formation of pseudopodia by Dictyostelium cells. We have observed that the formation of pseudopodia is highly ...
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