Search results for "Quantitative Biology::Subcellular Processes"
showing 10 items of 97 documents
Nonlinear dynamics of semiflexible magnetic filaments in an ac magnetic field
2006
Flexible spontaneously magnetized filaments exist in the living world (magnetotactic bacteria) and arise in magnetic colloids with large magnetodipolar interaction parameter. We demonstrate that these filaments possess variety of novel nonlinear phenomena in an ac magnetic field: orientation of the filament in the direction perpendicular to the field and the development of the oscillating U-like shapes, which presumably can lead to the formation of rings of magnetic filaments. It is found that these phenomena are determined by the development of the localized boundary modes of the filament deformation. We have illustrated by qualitative estimates that the phenomena found may be useful for i…
FLEXIBLE FERROMAGNETIC FILAMENTS AS ARTIFICIAL CILIA
2011
The model of an artificial cilia as a flexible ferromagnetic filament in a rotating magnetic field is proposed. Numerical algorithm for the simulation of its behavior is developed and the characteristic shapes of the filament with one fixed end under the action of a rotating field are found. It is concluded that ferromagnetic filaments may be used as mixers in microfluidics.
The Influence of Filtration of Atrasine on the Spectrum of Positron Lifetimes in Immobilized Liquid Filtration Membranes
2006
The spectra of positron lifetimes were investigated in elements which were later used to form an immobilized liquid membrane and also in the immobilized liquid membrane, after different times of atrasine filtration. Next, the spectra of positron lifetimes were separated out into three components. The values of the components of the positron lifetimes spectrum indicated the formation of the Ps-atom both in the elements composing the membrane and in the very membrane itself. An influence of the filtration time of atrasine on the values of all components of positron lifetimes spectrum was found. On the basis of Eldrup–Tao model, changes in the sizes of spherical free spaces in the membrane and…
A POSSIBLE SOLUTION TO THE HARD PROBLEM OF CONSCIOUSNESS USING MULTIDIMENSIONAL APPROACH
2012
In this work a new solution to the hard problem of consciousness using multidimensional approach [1-3] is proposed. It is shown that our perceptions may be interpreted as elastic oscillations of a two dimensional membrane with closed topology embedded in our brains. According to the model our universe is also a three dimensional elastic membrane embedded into the higher dimensional space-time. The model allows us to create a unified world picture where physical and perceptual aspects of the reality are complementary. We can observe our 2d self-membranes through our perceptions, which are encoded in elastic oscillations of the elastic membrane. According to the theory, elastic membranes occu…
Motion of magnetotactic bacteria swarms in an external field
2017
Magnetotactic bacteria moving on circular orbits form hydrodynamically bound states. When close to a surface and with the tilting of the field in a direction close to the perpendicular to this surface these swarms move perpendicularly to the tilting angle. We describe quantitatively this motion by a continuum model with couple stress arising from the torques produced by the rotary motors of the amphitrichous magnetotactic bacteria. The model not only correctly describes the change of direction of swarm motion while inverting the tangential field but also predicts reasonable value of the torque produced by the rotary motors.
"Table 18" of "Search for heavy particles decaying into a top-quark pair in the fully hadronic final state in $pp$ collisions at $\sqrt{s} =13$ TeV w…
2020
Expected and observed upper limits on the cross-section times branching fraction of V1 vector mediator decaying into top-quark pair as a function of the mediator mass.
A Ferrite Tubular Linear Motor (FTLM): Analysis and design
2015
The electromagnetic linear machines have wide applications in the electromagnetic aircraft launch systems [1] and in transportation systems [2]. Additional energy saving and efficiency can be achieved using a linear motor in the refrigeration application [3]. Linear electromagnetic machines are also very suitable for high-speed packaging, manufacturing sectors and precision positioning. There are different linear motor topologies. Tubular permanent-magnets are particularly attractive since they have a high thrust force density and high efficiency, no end windings, and zero net attractive force between stator and armature. There are various tubular motor topologies, in which the armature may…
An Extended Filament Based Lamellipodium Model Produces Various Moving Cell Shapes in the Presence of Chemotactic Signals
2015
The Filament Based Lamellipodium Model (FBLM) is a two-phase two-dimensional continuum model, describing the dynamcis of two interacting families of locally parallel actin filaments (C.Schmeiser and D.Oelz, How do cells move? Mathematical modeling of cytoskeleton dynamics and cell migration. Cell mechanics: from single scale-based models to multiscale modeling. Chapman and Hall, 2010). It contains accounts of the filaments' bending stiffness, of adhesion to the substrate, and of cross-links connecting the two families. An extension of the model is presented with contributions from nucleation of filaments by branching, from capping, from contraction by actin-myosin interaction, and from a pr…
Tuning active Brownian motion with shot noise energy pulses
2009
The main aim of this work is to explore the possibility of modeling the biological energy support mediated by absorption of ATP (adenosine triphosphate) as an energetic shot noise. We develop a general model with discrete input of energy pulses and study shot-noise-driven ratchets. We consider these ratchets as prototypes of Brownian motors driven by energy-rich ATP molecules. Our model is a stochastic machine able to acquire energy from the environment and convert it into kinetic energy of motion. We present characteristic features and demonstrate the possibility of tuning these motors by adapting the mean frequency of the discrete energy inputs, which are described as a special shot noise…
Investigation of Temperature-Induced Phase Transitions in DOPC and DPPC Phospholipid Bilayers Using Temperature-Controlled Scanning Force Microscopy
2004
Under physiological conditions, multicomponent biological membranes undergo structural changes which help define how the membrane functions. An understanding of biomembrane structure-function relations can be based on knowledge of the physical and chemical properties of pure phospholipid bilayers. Here, we have investigated phase transitions in dipalmitoylphosphatidylcholine (DPPC) and dioleoylphosphatidylcholine (DOPC) bilayers. We demonstrated the existence of several phase transitions in DPPC and DOPC mica-supported bilayers by both atomic force microscopy imaging and force measurements. Supported DPPC bilayers show a broad L(beta)-L(alpha) transition. In addition to the main transition …