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Results 301 - 350 of 1889
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Soofi Shauheen S - - 2009
Recent studies indicate that the biophysical properties of the cellular microenvironment strongly influence a variety of fundamental cell behaviors. The extracellular matrix's (ECM) response to mechanical force, described mathematically as the elastic modulus, is believed to play a particularly critical role in regulatory and pathological cell behaviors. The basement membrane ...
Patwa Z - - 2009
Lytic viruses are obligate parasites whose population dynamics are necessarily coupled to the dynamics of their host-cell population. The adaptation rate of these viruses has attracted considerable scientific interest, as they are a key model organism in experimental evolution. Nevertheless, to date mathematical models of experimental evolution have largely ignored ...
Nakamasu Akiko - - 2009
The reaction-diffusion system is one of the most studied nonlinear mechanisms that generate spatially periodic structures autonomous. On the basis of many mathematical studies using computer simulations, it is assumed that animal skin patterns are the most typical examples of the Turing pattern (stationary periodic pattern produced by the reaction-diffusion ...
Li Weimin - - 2009
Early studies on cell cycle regulation were based on experiments in model systems (Yeast, Xenopus, Starfish, Drosophila) and have shaped the way we understand many events that control the cell cycle. Although these model systems are of great value, the last decade was highlighted by studies done in human cells ...
Blanchard Guy B GB Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, - - 2009
The dynamic reshaping of tissues during morphogenesis results from a combination of individual cell behaviors and collective cell rearrangements. However, a comprehensive framework to unambiguously measure and link cell behavior to tissue morphogenesis is lacking. Here we introduce such a kinematic framework, bridging cell and tissue behaviors at an intermediate, ...
Khabiry Masoud - - 2009
Microstructures that generate shear-protected regions in microchannels can rapidly immobilize cells for cell-based biosensing and drug screening. Here, a two-step fabrication method is used to generate double microgrooves with various depth ratios to achieve controlled double-level cell patterning while still providing shear protection. Six microgroove geometries are fabricated with different ...
Ribba B - - 2009
The aim here was to explore the potential of pharmacokinetic (PK)/pharmacodynamic (PD) and physiopathological parameters in explaining the primary effects of an anti-cancer treatment that targets cells in a specific cell cycle phase. The authors applied a theoretical multi-scale disease model of tumour growth that integrates cancer processes at the ...
Sakaguchi Hidetsugu - - 2009
We propose a kind of reaction-diffusion equations for cell differentiation, which exhibits the Turing instability. If the diffusivity of some variables is set to be infinity, we get coupled competitive reaction-diffusion equations with a global feedback term. The size ratio of each cell type is controlled by a system parameter ...
Demontis Pierfranco - - 2009
Local, discrete models of self-interacting multisite adsorption cells have been shown to be able to provide a coarse-grained representation of equilibrium properties of small molecules adsorbed in nanoporous materials at the mesoscopic scale. In the present work we show how the essential statistical properties of a host cell of structured ...
Park Joong Yull - - 2009
Cells are very sensitive to various microenvironmental cues, including mechanical stress and chemical gradients. Therefore, physiologically relevant models of cells should consider how cells sense and respond to microenvironmental cues. This can be accomplished by using microfluidic systems, in which fluid physics can be realized at a nanoliter scale. Here ...
Zeng Dehong - - 2010
Schlemm's canal (SC) endothelial cells are likely important in the physiology and pathophysiology of the aqueous drainage system of the eye, particularly in glaucoma. The mechanical stiffness of these cells determines, in part, the extent to which they can support a pressure gradient and thus can be used to place ...
Nag Ambarish - - 2009
Ligand-induced receptor aggregation is a well-known mechanism for initiating intracellular signals but oligomerization of distal signaling molecules may also be required for signal propagation. Formation of complexes containing oligomers of the transmembrane adaptor protein, linker for the activation of T cells (LAT), has been identified as critical in mast cell ...
Wasungu L - - 2009
Electropermeabilization is a physical method to deliver molecules into cells and tissues. Clinical applications have been successfully developed for antitumoral drug delivery and clinical trials for gene electrotransfer are currently underway. However, little is known about the mechanisms involved in this transfer. The main difficulties stem from the lack of ...
Valentiner Ursula - - 2009
BACKGROUND: Inhibition of the proteasome-ubiquitin pathway has shown to exert growth inhibitory effects on several human carcinoma cell lines. In this study, the influence of bortezomib on human neuroblastoma cells was investigated. MATERIALS AND METHODS: Cell proliferation of seven human neuroblastoma cell lines under bortezomib treatment was assessed by a ...
Händel N - - 2009
Physical interactions between different cell types are a requirement for the initiation and maintenance of immune responses. The distribution pattern of cells within a tissue may result from specific cell-cell-interactions or random distribution. Tissue architecture, degree of inflammation, frequencies of cells, number of contact partners, cell type, and size as ...
Thompson Kerry - - 2009
A high percentage of patients with temporal lobe epilepsy (TLE) are refractory to conventional pharmacotherapy. The progressive neurodegenerative processes associated with a lifetime of uncontrolled seizures mandate the development of alternative approaches to treat this disease. Transplantation of inhibitory cells has been suggested as a potential therapeutic strategy to achieve ...
Yamamoto T - - 2009
Dermatofibromas are benign dermal nodules usually seen on the extremities; however, whether a dermatofibroma is a reactive fibrous hyperplasia or a true neoplasm is still unclear. Fibrous type dermatofibromas might be regarded as the symptom of local fibrotic processes and thus present a possible model of local fibrosis. Interaction between ...
Myers Catherine E - - 2009
We present a simple computational model of the dentate gyrus to evaluate the hypothesis that pattern separation, defined as the ability to transform a set of similar input patterns into a less-similar set of output patterns, is dynamically regulated by hilar neurons. Prior models of the dentate gyrus have generally ...
Baranyi József - - 2009
In Quantitative Microbial Risk Assessment, it is vital to understand how lag times of individual cells are distributed over a bacterial population. Such identified distributions can be used to predict the time by which, in a growth-supporting environment, a few pathogenic cells can multiply to a poisoning concentration level. We ...
Hermelink Antje - - 2009
Single cells in genetically homogeneous microbial cultures exhibit marked phenotypic heterogeneity that is considered to bolster the fitness of the whole population. Heterogeneity on the single-cell level is typically masked in conventional studies of microbial populations, which rely on data averaged across thousands or millions of cells in a sample. ...
Hirashima Tsuyoshi - - 2009
In the early kidney development, a simple epithelial tube called ureteric bud is derived from the intermediate mesoderm and undergoes a complex process of growth and terminal bifid branching. The branching of the ureteric bud is achieved by different cellular behaviors including cell proliferation and chemotaxis. In this paper, we ...
Wei Hsiang-Chun - - 2009
To be compared with the wavelength modulation technique for measuring two-dimensional (2D) cell parameters of a twisted nematic liquid crystal (TN-LC), we propose an amplitude-sensitive heterodyne ellipsometer (ASHE) of a single wavelength that is able to characterize TN-LC in 2D quantitatively. A quarter-wave plate (QWP) is rotated continuously in this ...
Gurgel Leandro Vinícius Alves - - 2009
Succinylated mercerized cellulose (cell 1) was used to synthesize an anion exchange resin. Cell 1, containing carboxylic acid groups was reacted with triethylenetetramine to introduce amine functionality to this material to obtain cell 2. Cell 2 was reacted with methyl-iodide to quaternize the amine groups from this material to obtain ...
Sasagawa, Fumiyoshi
In order to understand biological phenomena, a new mathematical field was proposed by T. Kitagawa in 1970 and it was named biomathematics. T. Kitagawa and M. Yamaguchi discussed cell spaces which are one of approaches to establish biomathematics. More than two states are introduced in the cell space. By algebraic ...
Sasagawa, Fumiyoshi
This paper is one of a series of the papers treating stable configurations in cell space. The strong-week relations between states are introduced in the local transition rule of the cell space. The local transition rule is systematically represented by the threshold type function. The pattern of stable configuration is ...
Csikász-Nagy Attila - - 2009
One of the early success stories of computational systems biology was the work done on cell-cycle regulation. The earliest mathematical descriptions of cell-cycle control evolved into very complex, detailed computational models that describe the regulation of cell division in many different cell types. On the way these models predicted several ...
Bylski-Austrow Donita I - - 2009
BACKGROUND: Hemiepiphysiodesis is a potential method to treat idiopathic juvenile scoliosis early. The purpose of the present study was to investigate a mechanism of curve creation in the pig thoracic model of spinal hemiepiphysiodesis by determining whether the structure of the vertebral growth plate varied with distance from the stapled, ...
Ratiani L - - 2009
Increasing of number of various therapeutic agents or medications on the world market require the development of rapid and comparatively cheap methodology for screening of these preparations, elucidation their efficacy and mechanisms of action. In article was investigated the methodology based on modeling of human lymphoblastoid T-cell line Jurkat for ...
Krinke Dana - - 2009
Heart diseases represent the most common cause of death in industrialised countries. For this reason target identification and development of novel anti-target drugs are in the focus of pharmaceutical industry. Especially cardiac infarct is a topical field of research. A bottleneck in today's long-duration and high-cost drug development is the ...
Hu Yi-Ling - - 2009
Autoimmune diseases are marked by the presence of class-switched, high-affinity autoantibodies with pathogenic potential. Costimulation plays an important role in the activation of T cells and the development of T cell-dependent B cell responses. ICOS plays an indispensable role in the development of follicular helper T cells (T(FH) cells), which ...
Spetsieris Konstantinos - - 2009
Cell population balance (CPB) models can account for the phenotypic heterogeneity that characterizes isogenic cell populations. To utilize the predictive power of these models, however, we must determine the single-cell reaction and division rates as well as the partition probability density function of the cell population. These functions can be ...
Porro Danilo - - 2009
Model organisms and in particular the budding yeast Saccharomyces cerevisiae have been instrumental in advancing our understanding of cell cycle progression. The asymmetric division of the budding yeast and the tight coupling between cell growth and division have challenged the theoretical understanding of the cell size structure of growing yeast ...
Li, Fang
Recently, cell-based biosensors have attracted many attentions because of their potential applications in fundamental biological research, drug development, and other fields. Acoustic wave biosensors offer powerful tools to probe cell behaviors and properties in a non-invasive, simple, and quantitative manner. Current studies on cell-based acoustic wave sensors are focused on ...
Manica, Evandro
The preBotzinger complex located at the ventrolateral medulla in the brainstem is believed to have an important role in generating the respiratory rhythm in mammals, specially the inspiratory process [56]. Keeping this in mind, we will study a small network of such cells by means of a minimal model suggested ...
K.K.T. Thanapalan, G.P. Liu, ...
This paper presents a review and analysis of a fuel cell system modelling and controller design for electric fuel cell vehicle applications. The paper begins by presenting the basic principal of PEM fuel cell dynamics. The work proceeds to investigate models and controller design techniques for fuel cell systems.
Wu Yilin - - 2009
Many bacteria can rapidly traverse surfaces from which they are extracting nutrient for growth. They generate flat, spreading colonies, called swarms because they resemble swarms of insects. We seek to understand how members of any dense swarm spread efficiently while being able to perceive and interfere minimally with the motion ...
Poignard, Clair
The paper presents heuristics to reduce several difficulties related to the determination of the transmembrane voltage potential (TMP) on cells with arbitrary smooth shape. We show how the thin weakly conducting membrane can be replaced by asymptotically equivalent transmission conditions at the interface between the cell interior (the cytoplasm) and ...
Tsui, Simon
Cell-cell adhesion is important to understanding the mechanics of cell-cell interactions. A recent study of cell adhesion was conducted by others using an Atomic Force Microscopy to measure forces when two cells are brought together and then pulled apart. When the two cells come in contact, the adhesion molecules of ...
Entcheva Emilia - - 2009
This study tests the hypothesis that the cell cytoskeletal (CSK) network can rearrange from geodesic dome type structures to stress fibers in response to microenvironmental cues. The CSK geodesic domes are highly organized actin microarchitectures within the cell, consisting of ordered polygonal elements. We studied primary neonatal rat cardiac fibroblasts. ...
Kienitz, Brian L.
Polymer electrolyte membrane fuel cells (PEMFCs) running on hydrogen hold great promise to provide a source of clean energy and reduce our dependence on foreign oil, but fuel cells must become more durable before they can be implemented. The effects of cationic contamination, the process of foreign cations replacing protons ...
Markus Grötsch
The connection between PEM fuel cells and common DC-DC converters is examined. The analysis is model-based and done for boost, buck and buck-boost converters. In a first step, the effect of the converter ripples upon the PEM fuel cell is shown. They introduce oscillations in the fuel cell. Their appearance ...
Lal, Anita
This proposal is concerned with the functional role of merlin in arachnoidal and meningioma cells. In year 1, we developed meningioma-specific NF2 model systems. In Year 2, we characterized the phenotypic effects of these model systems. We showed that merlin loss enhances loss of contact inhibition of growth, increases anchorage ...
Zhang, Zikai
Abstract Over the past few years, the trend in microprocessor design has shifted from increasing the clock frequencies to multi-core designs that embed multiple processing cores on the same chip. This has meant that we can no longer rely on increasing clock frequencies in order to improve the performance of ...
Ma Xiaoyan - - 2009
We use laser hole drilling to assess the mechanics of an embryonic epithelium during development-in vivo and with subcellular resolution. We ablate a subcellular cylindrical hole clean through the epithelium and track the subsequent recoil of adjacent cells (on ms time scales). We investigate dorsal closure in the fruit fly ...
Roy Sushmita - - 2009
Analysis of condition-specific behavior under stressful environmental conditions can provide insight into mechanisms causing different healthy and diseased cellular states. Functional networks (edges representing statistical dependencies) inferred from condition-specific expression data can provide fine-grained, network level information about conserved and specific behavior across different conditions. In this paper, we examine ...
Sohka Takayuki - - 2009
ABSTRACT: BACKGROUND: Gradients of morphogens pattern cell fate - a phenomenon that is especially important during development. A simple model system for studying how morphogens pattern cell behavior would overcome difficulties inherent in the study of natural morphogens in vivo. A synthetic biology approach to building such a system is ...
van Zon Jeroen S - - 2009
Phagocytosis is the process by which cells internalize particulate material, and is of central importance to immunity, homeostasis and development. Here, we study the internalization of immunoglobulin G-coated particles in cells transfected with Fcgamma receptors (FcgammaRs) through the formation of an enveloping phagocytic cup. Using confocal microscopy, we precisely track ...
Kim Mun Ju - - 2009
T-killer cells of the immune system eliminate virus-infected and tumorous cells through direct cell-cell interactions. Reorientation of the killing apparatus inside the T cell to the T-cell interface with the target cell ensures specificity of the immune response. The killing apparatus can also oscillate next to the cell-cell interface. When ...
Baker Ruth E - - 2009
Since the discovery of gene products oscillating during the formation of vertebral segments, much attention has been directed toward eluciating the molecular basis of the so-called segmentation clock. What research has told us is, that even in the most simple vertebrates, enormously complicated gene networks act in each cell to ...
Hernandez Rosa - - 2009
Although the role of invasion in the virulence of Candida albicans has been demonstrated, the mechanism that governs fungal invasion is not fully understood. Among the tools that exist to fill these gaps in knowledge, in vitro tissue models based on reconstituted human epithelia (RHE) have already been developed. Such ...
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