Duty ratio of cooperative molecular motors
Nadiv Dharan and Oded Farago
Molecular motors are found throughout the cells of the human body and have many different and important roles. These micromachines move along filament tracks and have the ability to convert chemical energy into mechanical work that powers cellular motility. Different types of motors are characterize ... [Phys. Rev. E 85, 021904 ] published .
Identifying Dynamical Bottlenecks of Stochastic Transitions in Biochemical Networks
Christopher C. Govern, Ming Yang, and Arup K. Chakraborty
In biochemical networks, identifying key proteins and protein-protein reactions that regulate fluctuation-driven transitions leading to pathological cellular function is an important challenge. Using large deviation theory, we develop a semianalytical method to determine how changes in protein expre ... [Phys. Rev. Lett. 108, 058102 ] published .
Growth dynamics of cancer cell colonies and their comparison with noncancerous cells
M. A. C. Huergo, M. A. Pasquale, P. H. Gonzalez, A. E. Bolzan, and A. J. Arvia
The two-dimensional (2D) growth dynamics of HeLa (cervix cancer) cell colonies was studied following both their growth front and the pattern morphology evolutions utilizing large population colonies exhibiting linearly and radially spreading fronts. In both cases, the colony profile fractal dimensio ... [Phys. Rev. E 85, 011918 ] published .
Fluctuations, Dynamics, and the Stretch-Coil Transition of Single Actin Filaments in Extensional Flows
Vasily Kantsler and Raymond E. Goldstein
Semiflexible polymers subject to hydrodynamic forcing play an important role in cytoskeletal motions in the cell, particularly when filaments guide molecular motors whose motions create flows. Near hyperbolic stagnation points, filaments experience a competition between bending elasticity and tensio ... [Phys. Rev. Lett. 108, 038103 ] published .
Contractile network models for adherent cells
P. Guthardt Torres, I. B. Bischofs, and U. S. Schwarz
Cells sense the geometry and stiffness of their adhesive environment by active contractility. For strong adhesion to flat substrates, two-dimensional contractile network models can be used to understand how force is distributed throughout the cell. Here we compare the shape and force distribution fo ... [Phys. Rev. E 85, 011913 ] published .
Structure and dynamics of nano-sized raft-like domains on the plasma membrane
Fernando E. Herrera and Sergio Pantano
Cell membranes are constitutively composed of thousands of different lipidic species, whose specific organization leads to functional heterogeneities. In particular, sphingolipids, cholesterol and some proteins associate among them to form stable nanoscale domains involved in recognition, signaling, ... [J. Chem. Phys. 136, 015103 (2012)] published Thu Jan 5, 2012.
Curvature multiphase field model for phase separation on a membrane
C. Varea, R. A. Barrio, and A. Hernandez-Machado
We propose a model to describe the physical mechanisms by which chemical substances separate in the vicinity of a membrane. We assume that the adsorption of the different components of a complex liquid on a membrane is governed by interactions that couple them to the spontaneous curvature of the mem ... [Phys. Rev. E 84, 061922 ] published .
The Effects of Power and Feeding Rate on Production of Polyurethane Nanofiber with Electrospinning Process
Mustafa O. Oteyaka, Emre Ozel, and M. Mustafa Yıldırım
Nowadays, nanofiber made of polymers becomes popular on biomaterials research. One of the main reasons to need of nanofiber size is to mimic extracellular matrix (ECM) that play a critical role in proliferation, cell motility and intercellular signaling in vascular graft replacement. In this study p ... [AIP Conf. Proc. 1400, 216 (2011)] published Wed Dec 28, 2011.
Boundary-induced orientation of dynamic filament networks and vesicle agglomerations
Philip Greulich and Ludger Santen
We find a statistical mechanism that can adjust orientations of intracellular filaments to cell geometry in the absence of organizing centers. The effect is based on random and isotropic filament (de-)polymerization dynamics and is independent of filament interactions and explicit regulation. It can ... [Phys. Rev. E 84, 060902 ] published .
Theoretical Study on Temperature Dependence of Cellular Uptake of QDs Nanoparticles
Aili Zhang, Yingxue Guan, and Lisa X. Xu
Cellular uptake kinetics of nanoparticles is one of the key issues determining the design and application of the particles. Models describing nanoparticles intrusion into the cell mostly take the endocytosis process into consideration, and the influences of electrical charges, sizes, concentrations ... [J. Biomech. Eng. 133, 124502 (2011)] published Wed Dec 21, 2011.
Room-temperature, atmospheric plasma needle reduces adenovirus gene expression in HEK 293A host cells
Z. Xiong, X. Lu, Y. Cao, Q. Ning, K. Ostrikov et al.
Room-temperature, atmospheric-pressure plasma needle treatment is used to effectively minimize the adenovirus (AdV) infectivity as quantified by the dramatic reduction of its gene expression in HEK 293A primary human embryonic kidney cells studied by green fluorescent protein imaging. The AdV titer ... [Appl. Phys. Lett. 99, 253703 (2011)] published Tue Dec 20, 2011.
Stochastic binary modeling of cells in continuous time as an alternative to biochemical reaction equations
Shunsuke Teraguchi, Yutaro Kumagai, Alexis Vandenbon, Shizuo Akira, and Daron M Standley
We have developed a coarse-grained formulation for modeling the dynamic behavior of cells quantitatively, based on stochasticity and heterogeneity, rather than on biochemical reactions. We treat each reaction as a continuous-time stochastic process, while reducing each biochemical quantity to a bina ... [Phys. Rev. E 84, 062903 ] published .
Fluorescent protein barrel fluctuations and oxygen diffusion pathways in mCherry
Prem P. Chapagain, Chola K. Regmi, and William Castillo
Fluorescent proteins (FPs) are valuable tools as biochemical markers for studying cellular processes. Red fluorescent proteins (RFPs) are highly desirable for in vivo applications because they absorb and emit light in the red region of the spectrum where cellular autofluorescence is low. The natural ... [J. Chem. Phys. 135, 235101 (2011)] published Thu Dec 15, 2011.
Length-dependent dynamics of microtubules
Vandana Yadav and Sutapa Mukherji
Certain regulatory proteins influence the polymerization dynamics of microtubules by inducing catastrophe with a rate that depends on the microtubule length. Using a discrete formulation, here we show that, for a catastrophe rate proportional to the microtubule length, the steady-state probability d ... [Phys. Rev. E 84, 062902 ] published .
Dynamic scaling in phase separation kinetics for quasi-two-dimensional membranes
Brian A. Camley and Frank L. H. Brown
We consider the dynamics of phase separation in lipid bilayer membranes, modeled as flat two-dimensional liquid sheets within a bulk fluid, both in the creeping flow approximation. We present scaling arguments that suggest asymptotic coarsening in these systems is characterized by a length scale R(t ... [J. Chem. Phys. 135, 225106 (2011)] published Wed Dec 14, 2011.
In-Plane Dynamics of Membranes with Immobile Inclusions
Naomi Oppenheimer and Haim Diamant
Cell membranes are anchored to the cytoskeleton via immobile inclusions. We investigate the effect of such anchors on the in-plane dynamics of a fluid membrane and mobile inclusions (proteins) embedded in it. The immobile particles lead to a decreased diffusion coefficient of mobile ones and suppres ... [Phys. Rev. Lett. 107, 258102 ] published .
Membrane morphology induced by anisotropic proteins
Kiyotaka Akabori and Christian D. Santangelo
There are a great many proteins that localize to and collectively generate curvature in biological fluid membranes. We study changes in the topology of fluid membranes due to the presence of highly anisotropic, curvature-inducing proteins. Generically, we find a surprisingly rich phase diagram with ... [Phys. Rev. E 84, 061909 ] published .
Interaction Of ZnO Nanoparticles With Food Borne Pathogens Escherichia coli DH5alpha and Staphylococcus aureus 5021 & Their Bactericidal Efficacy
Pawan Kaur, Rajesh Thakur, Sandeep Kumar, and Neeraj Dilbaghi
Bactericidal activity of ZnO nanoparticles (np) against the food borne pathogens E. coli DH5alpha (Gramve) and & S. aureus 5021 (Gram+ve), and the mechanism of their interaction with target microbes was studied. Bactericidal activity of ZnO np was attributed to disruption of cell membrane causing cy ... [AIP Conf. Proc. 1393, 153 (2011)] published Mon Dec 12, 2011.
Mechanochemical model of cell migration on substrates of varying stiffness
Tanny Lai and K.-H. Chiam
Cells propel themselves along a substrate by organizing structures at the leading edge called lamellipodia that contain the actin network, myosin, integrin, and other proteins. In this article, we describe a quantitative model that couples the response of stretch-sensitive proteins in the lamellipod ... [Phys. Rev. E 84, 061907 ] published .
Stable, biocompatible lipid vesicle generation by solvent extraction-based droplet microfluidics
Shia-Yen Teh, Ruba Khnouf, Hugh Fan, and Abraham P. Lee
In this paper, we present a microfluidic platform for the continuous generation of stable, monodisperse lipid vesicles 20110 [mu]m in diameter. Our approach utilizes a microfluidic flow-focusing droplet generation design to control the vesicle size by altering the system's fluid flow rates to genera ... [Biomicrofluidics 5, 044113 (2011)] published Fri Dec 9, 2011.
Mechanics of soft composites of rods in elastic gels
Moumita Das and F. C. MacKintosh
We report detailed theoretical investigations of the micromechanics and bulk elastic properties of composites consisting of randomly distributed stiff fibers embedded in an elastic matrix in two and three dimensions. Recent experiments [V. Pelletier, N. Gal, P. Fournier, and M. L. Kilfoil, Phys. Rev ... [Phys. Rev. E 84, 061906 ] published .