Analysis of bacterial chemotactic response using dynamic laser speckle
Silvia E. Murialdo, Gonzalo H. Sendra, Lucia I. Passoni, Ricardo Arizaga, J. Froilan Gonzalez et al.
Chemotaxis has a meaningful role in several fields, such as microbial physiology, medicine and biotechnology. We present a new application of dynamic laser speckle (or biospeckle) to detect different degrees of bacterial motility during chemotactic response experiments. Encouraging results showed di ... [J. Biomed. Opt. 14, 064015 (2009)] published Thu Nov 19, 2009.
Enhanced low-Reynolds-number propulsion in heterogeneous viscous environments
A. M. Leshansky
It has been known for some time that some microorganisms can swim faster in high-viscosity gel-forming polymer solutions. These gel-like media come to mimic highly viscous heterogeneous environment that these microorganisms encounter in-vivo. The qualitative explanation of this phenomena first offer ... [Phys. Rev. E 80, 051911 (2009)] published Wed Nov 18, 2009.
Mechanical Stress Analysis of Microfluidic Environments Designed for Isolated Biological Cell Investigations
Sean S. Kohles, Nathalie Neve, Jeremiah D. Zimmerman, and Derek C. Tretheway
Advancements in technologies for assessing biomechanics at the cellular level have led to discoveries in mechanotransduction and the investigation of cell mechanics as a biomarker for disease. With the recent development of an integrated optical tweezer with micron resolution particle image velocime ... [J. Biomech. Eng. 131, 121006 (2009)] published Tue Nov 10, 2009.
The adventures of Dicty, the Dictyostelium cell
Meghan Driscoll, Rael Kopace, Linjie Li, Colin McCann, John Watts et al.
Abstract not available. [Chaos 19, 041110 (2009)] published Tue Oct 27, 2009.
Hole mobility and transport mechanisms in lambda-DNA
Mattias Jakobsson and Sven Stafstrom
We have performed a study of charge transport in lambda-DNA using a recently developed model based on Marcus theory and dynamic Monte Carlo simulations. The model accounts for charge delocalization over multiple adjacent identical nucleobases. Such delocalized states are found to act as traps for ch ... [J. Chem. Phys. 131, 155102 (2009)] published Mon Oct 19, 2009.
Parameter effects on binding chemistry in crowded media using a two-dimensional stochastic off-lattice model
Byoungkoo Lee, Philip R. LeDuc, and Russell Schwartz
The intracellular environment imposes a variety of constraints on biochemical reaction systems that can substantially change reaction rates and equilibria relative to an ideal solution-based environment. One of the most notable features of the intracellular environment is its dense macromolecular cr ... [Phys. Rev. E 80, 041918 (2009)] published Wed Oct 14, 2009.
Conductive versus capacitive coupling for cell electroporation with nanosecond pulses
David M. French, Michael D. Uhler, Ronald M. Gilgenbach, and Y. Y. Lau
Experiments and simulations were performed to determine the difference between capacitive coupling and conductive connection for the electroporation of cells. The pulses used in the experiments have a peak voltage of 24 kV, 0.6 ns rise time, and 1.6 ns full width at half maximum. Experiments perform ... [J. Appl. Phys. 106, 074701 (2009)] published Thu Oct 8, 2009.
The Use Of Laser Irradiation To Stimulate Adipose Derived Stem Cell Proliferation And Differentiation For Use In Autologous Grafts
Heidi Abrahamse
Stem cells are characterized by the qualities of self-renewal, long term viability, and the ability to differentiate into various cell types. Historically, stem cells have been isolated from the inner cell mass of blastocysts and harvesting these cells resulted in the death of the embryo leading to ... [AIP Conf. Proc. 1172, 95 (2009)] published Thu Oct 8, 2009.
Symmetry breaking mechanism for epithelial cell polarization
A. Veglio, A. Gamba, M. Nicodemi, F. Bussolino, and G. Serini
In multicellular organisms, epithelial cells form layers separating compartments responsible for different physiological functions. At the early stage of epithelial layer formation, each cell of an aggregate defines an inner and an outer side by breaking the symmetry of its initial state, in a proce ... [Phys. Rev. E 80, 031919 (2009)] published Tue Sep 29, 2009.
Modeling of Bubble Expansion-Induced Cell Mechanical Profile in Laser-Assisted Cell Direct Writing
Wei Wang, Gang Li, and Yong Huang
Cell damage due to the mechanical impact during laser-assisted cell direct writing has been observed and is a possible hurdle for broad applications of fragile cell direct writing. The objective of this study is to numerically investigate the bubble expansion-induced cell mechanical loading profile ... [J. Manuf. Sci. Eng. 131, 051013 (2009)] published Thu Sep 24, 2009.
Characterization of Hydrodynamic Surface Interactions of Escherichia coli Cell Bodies in Shear Flow
Tolga Kaya and Hur Koser
We experimentally demonstrate that nonflagellated Escherichia coli strains follow modified Jeffery orbits in shear flow near a surface. We fully characterize their Jeffery orbits as a function of their aspect ratios and distance from that surface. Thanks to the linearity of Navier-Stokes equations u ... [Phys. Rev. Lett. 103, 138103 (2009)] published Thu Sep 24, 2009.
From a discrete to a continuum model of cell dynamics in one dimension
Philip J. Murray, Carina M. Edwards, Marcus J. Tindall, and Philip K. Maini
Multiscale modeling is emerging as one of the key challenges in mathematical biology. However, the recent rapid increase in the number of modeling methodologies being used to describe cell populations has raised a number of interesting questions. For example, at the cellular scale, how can the appro ... [Phys. Rev. E 80, 031912 (2009)] published Wed Sep 23, 2009.
Multiscale Modeling of Cortical Neural Networks
Benjamin Torben-Nielsen and Klaus M. Stiefel
In this study, we describe efforts at modeling the electrophysiological dynamics of cortical networks in a multi-scale manner. Specifically, we describe the implementation of a network model composed of simple single-compartmental neuron models, in which a single complex multi-compartmental model of ... [AIP Conf. Proc. 1167, 15 (2009)] published Wed Sep 23, 2009.
Cells, cancer, and rare events: Homeostatic metastability in stochastic nonlinear dynamical models of skin cell proliferation
Patrick B. Warren
A recently proposed model for skin cell proliferation [E. Clayton et al., Nature (London) 446, 185 (2007)] is extended to incorporate mitotic autoregulation, and hence homeostasis as a fixed point of the dynamics. Unlimited cell proliferation in such a model can be viewed as a model for carcinogenes ... [Phys. Rev. E 80, 030903 (2009)] published Tue Sep 22, 2009.
Mechanical changes of living oocytes at maturation investigated by multiple particle tracking
Giuseppe Pesce, Lara Selvaggi, Antonio Caporali, Anna Chiara De Luca, Agostina Puppo et al.
We have studied the mechanical properties of the cytoplasm of starfish oocytes before and after maturation using the multiple particle tracking technique. Fluorescent microbeads are microinjected in oocytes of Astropecten aranciacus starfishes. Mechanical properties are obtained analyzing the mean-s ... [Appl. Phys. Lett. 95, 093702 (2009)] published Fri Sep 4, 2009.
Continuum Modeling of Biological Tissue Growth by Cell Division, and Alteration of Intracellular Osmolytes and Extracellular Fixed Charge Density
Gerard A. Ateshian, Kevin D. Costa, Evren U. Azeloglu, Barclay Morrison, III, and Clark T. Hung
A framework is formulated within the theory of mixtures for continuum modeling of biological tissue growth that explicitly addresses cell division, using a homogenized representation of cells and their extracellular matrix (ECM). The model relies on the description of the cell as containing a soluti ... [J. Biomech. Eng. 131, 101001 (2009)] published Tue Sep 1, 2009.
Analytical Solution of Traffic Cellular Automata Model
Shih-Ching Lo and Chia-Hung Hsu
Complex traffic system seems to be simulated successfully by cellular automaton (CA) models. Various models are developed to understand single-lane traffic, multilane traffic, lane-changing behavior and network traffic situations. However, the result of CA simulation can only be obtained after massi ... [AIP Conf. Proc. 1148, 441 (2009)] published Mon Aug 24, 2009.
The local cell curvature guides pseudopodia towards chemoattractants
Peter J. M. Van Haastert and Leonard Bosgraaf
Many eukaryotic cells use pseudopodia for movement towards chemoattractants. We developed a computer algorithm to identify pseudopodia, and analyzed how pseudopodia of Dictyostelium cells are guided toward cAMP. Surprisingly, the direction of a pseudopod is not actively oriented toward the gradient, ... [HFSP J. 3, 282 (2009)] published Wed Aug 19, 2009.
Steering Chiral Swimmers along Noisy Helical Paths
Benjamin M. Friedrich and Frank Julicher
Chemotaxis along helical paths towards a target releasing a chemoattractant is found in sperm cells and many microorganisms. We discuss the stochastic differential geometry of the noisy helical swimming path of a chiral swimmer. A chiral swimmer equipped with a simple feedback system can navigate in ... [Phys. Rev. Lett. 103, 068102 (2009)] published Thu Aug 6, 2009.
Noisy swimming at low Reynolds numbers
Jorn Dunkel and Irwin M. Zaid
Small organisms (e.g., bacteria) and artificial microswimmers move due to a combination of active swimming and passive Brownian motion. Considering a simplified linear three-sphere swimmer, we study how the swimmer size regulates the interplay between self-driven and diffusive behavior at low Reynol ... [Phys. Rev. E 80, 021903 (2009)] published Wed Aug 5, 2009.
Calculation of free energies in fluid membranes subject to heterogeneous curvature fields
Neeraj J. Agrawal and Ravi Radhakrishnan
We present a computational methodology for incorporating thermal effects and calculating relative free energies for elastic fluid membranes subject to spatially dependent intrinsic curvature fields using the method of thermodynamic integration. Based on a simple model for the intrinsic curvature imp ... [Phys. Rev. E 80, 011925 (2009)] published Thu Jul 30, 2009.
Photodynamic influence on anti-cancer immunity. (arXiv:0911.4074v1 [q-bio.CB])
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