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Results 351 - 400 of 1912
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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 ...
Biton Y Y - - 2009
We present a theoretical model to explain recent observations of the orientational response of cells to unidirectional curvature. Experiments show that some cell types when plated on a rigid cylindrical surface tend to reorient their shape and stress fibers along the axis of the cylinder, while others align their stress ...
Kam Yoonseok - - 2009
BACKGROUND: Traditional in vitro cell invasion assays focus on measuring one cell parameter at a time and are often less than ideal in terms of reproducibility and quantification. Further, many techniques are not suitable for quantifying the advancing margin of collectively migrating cells, arguably the most important area of activity ...
Nogueira-Ferreira F H - - 2009
We studied the behavior of virgin queens of the stingless bee species Schwarziana quadripunctata, Paratrigona lineata and Tetragona clavipes, investigating internal nest activities, including the cell provisioning and oviposition process. We made direct observation of queen behavior, with the aid of video filming. Forty-four virgin queens of S. quadripunctata were ...
Cailliau Katia - - 2009
To study protein function in cellular signaling, manual microinjection is a direct technique, but limited by the small size of many cells. The giant vertebrate cell, the Xenopus laevis oocyte, is a perfect model system to perform these studies. Oocytes are numerous and synchronous cells, arrested in the G2 phase ...
Veronika Merlin - - 2009
High content screening techniques are increasingly used to understand the regulation and progression of cell motility. The demand of new platforms, coupled with availability of terabytes of data has challenged the traditional technique of identifying cell populations by manual methods and resulted in development of high-dimensional analytical methods. In this ...
Kim Sean H J SH UCSF/UC Berkeley Joint Graduate Group in Bioengineering, University of California, Berkeley, California 94720, USA. - - 2009
Three-dimensional (3D) embedded cell cultures provide an appropriate physiological environment to reconstruct features of early glandular epithelial cancer. Although these are orders of magnitude simpler than tissues, they too are complex systems that have proven challenging to understand. We used agent-based, discrete event simulation modeling methods to build working hypotheses ...
Moon James J JJ Department of Microbiology, Center for Immunology, University of Minnesota Medical, Minneapolis, MN 55455, - - 2009
Over the last decade, significant advances have been made in the methodology for studying immune responses in vivo. It is now possible to follow almost every aspect of pathogen-specific immunity using in vivo models that incorporate physiological infectious doses and natural routes of infection. This new ability to study immunity ...
Lee Timothy K TK Bioengineering Department, Stanford University, 318 Campus Drive West, Stanford, CA 94305-5444, - - 2009
Nearly identical cells can exhibit substantially different responses to the same stimulus. We monitored the nuclear localization dynamics of nuclear factor kappaB (NF-kappaB) in single cells stimulated with tumor necrosis factor-alpha (TNF-alpha) and lipopolysaccharide (LPS). Cells stimulated with TNF-alpha have quantitative differences in NF-kappaB nuclear localization, whereas LPS-stimulated cells can ...
Crouch Adam S - - 2009
In this study, we have used nanoimprinting to create a range of micro- and nanoscale gratings, or their combination, in bulk polystyrene plates to investigate anisotropic cell behaviors of human dermal fibroblasts with respect to the aspect ratio (depth/width) of gratings. The depth and width of the polystyrene gratings both ...
Timp Winston - - 2009
We report on the physical parameters governing prokaryotic cell-to-cell signaling in a model biofilm. The model biofilm is comprised of bacteria that are genetically engineered to transmit and receive quorum-sensing (QS) signals. The model is formed using arrays of time-shared, holographic optical traps in conjunction with microfluidics to precisely position ...
Mishra, Bikash
Fuel cells are promising technology to meet the energy need of the future. This alternative energy source is clean and efficient, and with the continuous decrease in fossil fuel resources, one of the best bets towards sustaining our power needs. Fuel cells are being used in automobiles as well as ...
Kiang, Lee K.
We consider a sensor that is subject to false-positive and false-negative errors. The sensor searches for stationary threat objects such as ballistic missile launchers or improvised explosive devices. The objects are located in a certain area of interest, which is divided into area-cells. The area-cells are defined such that each ...
Choi Kyung-Suk KS Department of Molecular Genetics, University of Florida, College of Medicine, Gainesville, Florida 32610, - - 2008
A classically identified "notochordal" cell population in the nucleus pulposus is thought to regulate disk homeostasis. However, the embryonic origin of these cells has been under dispute for >60 years. Here we provide the first direct evidence that all cell types in the adult mouse nucleus pulposus are derived from ...
Voigt, Ina K.
It is well known that all cells of the Voronoi diagram of a Delaunay set are polytopes. For a finite point set, all these cells are still polyhedra. So the question arises, if this observation holds for all discrete point sets: Are always all Voronoi cells of an arbitrary, infinite ...
Chen L Leon - - 2009
Aberrantly regulated cell motility is a hallmark of cancer cells. A hybrid agent-based model has been developed to investigate the synergistic and antagonistic cell motility-impacting effects of three microenvironment variables simultaneously: chemoattraction, haptotactic permission, and biomechanical constraint or resistance. Reflecting distinct cell-specific intracellular machinery, the cancer cells are modeled as ...
Dailey H L - - 2009
The acute respiratory distress syndrome (ARDS) is characterized by fluid accumulation in small pulmonary airways. The reopening of these fluid-filled airways involves the propagation of an air-liquid interface that exerts injurious hydrodynamic stresses on the epithelial cells (EpC) lining the airway walls. Previous experimental studies have demonstrated that these hydrodynamic ...
Smits Anke M - - 2009
Development involves an interplay between various cell types from their birth to their disappearance by differentiation, migration, or death. Analyzing these interactions provides insights into their roles during the formation of a new organism. As a study tool for these interactions, we have created a model based on embryoid bodies ...
Yguel, Manuel
Reliable and efficient perception in dynamic environments especially in densely cluttered environments is still a challenge today. Most of the systems used for target tracking are based on object models. Such approaches usually fail in complex environments with a variety of different moving obstacles. In this report, we propose a ...
Harvey M J - - 2008
Accelerator processors like the new Cell processor are extending the traditional platforms for scientific computation, allowing orders of magnitude more floating-point operations per second (flops) compared to standard central processing units. However, they currently lack double-precision support and support for some IEEE 754 capabilities. In this work, we develop a ...
Falou Omar - - 2008
The high frequency backscatter from cells with a nucleus to cell volume ratio of 0.50 cannot be adequately modeled as a homogeneous sphere. It was hypothesized that the cytoplasm of such cells is of fluid nature. This work attempts to model the ultrasound backscatter (10-62 MHz) from some non-nucleated biological ...
Linge Svein Ohm - - 2008
AIMS: To compute the effects of parameter perturbations for single ischemic cardiac cells, and to determine how perturbations influenced the tendency for the cells to undergo spontaneous depolarization (automaticity) during 20 min of acute ischemia. METHODS: A modified Luo-Rudy 1 cell model was used. Since the range of biological variation ...
Seale, AndreĢ P
Thesis (Ph. D.)--University of Hawaii at Manoa, 2002.
Slater Jennifer L - - 2009
The production of neurons to form the mammalian cortex, known as embryonic cortical neurogenesis, is a complex developmental process. Insight into the process of cell division during neurogenesis is provided by murine cortical cell lineage trees, recorded through experimental observation. Recurring patterns within cell lineage trees may be indicative of ...
Aubert M - - 2008
We examine the consequences of long-range effects on tumour cell migration. Our starting point are previous results of ours where we have shown that the migration patterns of glioma cells are best interpreted if one assumes attractive interactions between cells. Here we complement the cellular automaton model previously introduced by ...
Hutson M Shane - - 2008
Previous 2D and 3D models concluded that cell sorting requires cytoskeletal fluctuations and is stalled by high tension at heterotypic interfaces. New deterministic and stochastic models show that this is not true in 3D. Sorting in 3D involves both topological untangling and domain coalescence. Coalescence requires fluctuations and low tension, ...
Rubenstein Brenda M - - 2008
In this work, a cellular Potts model based on the differential adhesion hypothesis is employed to analyze the relative importance of select cell-cell and cell-extracellular matrix (ECM) contacts in glioma invasion. To perform these simulations, three types of cells and two ECM components are included. The inclusion of explicit ECM ...
Kapitanov Venedikt A - - 2008
We report investigations on newly designed compact photoacoustic gas cell resonator for laser gas analysis. This photoacoustic cell has a resonator with two times sensitivity compared with the previous result. Sensitivity comparisons between the simulation and the experimental results have been done. The comparisons show predicted result matches well with ...
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