TY  - JOUR
A1  - Goychuk, Igor
T1  - Viscoelastic subdiffusion in a random Gaussian environment
JF  - Physical chemistry, chemical physics : a journal of European Chemical Societies
N2  - Viscoelastic subdiffusion governed by a fractional Langevin equation is studied numerically in a random Gaussian environment modeled by stationary Gaussian potentials with decaying spatial correlations. This anomalous diffusion is archetypal for living cells, where cytoplasm is known to be viscoelastic and a spatial disorder also naturally emerges. We obtain some first important insights into it within a model one-dimensional study. Two basic types of potential correlations are studied: short-range exponentially decaying and algebraically slow decaying with an infinite correlation length, both for a moderate (several kBT, in the units of thermal energy), and strong (5–10kBT) disorder. For a moderate disorder, it is shown that on the ensemble level viscoelastic subdiffusion can easily overcome the medium's disorder. Asymptotically, it is not distinguishable from the disorder-free subdiffusion. However, a strong scatter in single-trajectory averages is nevertheless seen even for a moderate disorder. It features a weak ergodicity breaking, which occurs on a very long yet transient time scale. Furthermore, for a strong disorder, a very long transient regime of logarithmic, Sinai-type diffusion emerges. It can last longer and be faster in the absolute terms for weakly decaying correlations as compared with the short-range correlations. Residence time distributions in a finite spatial domain are of a generalized log-normal type and are reminiscent also of a stretched exponential distribution. They can be easily confused for power-law distributions in view of the observed weak ergodicity breaking. This suggests a revision of some experimental data and their interpretation.
Y1  - 2018
U6  - https://doi.org/10.1039/c8cp05238g
SN  - 1463-9076
SN  - 1463-9084
VL  - 20
IS  - 37
SP  - 24140
EP  - 24155
PB  - Royal Society of Chemistry
CY  - Cambridge
ER  - 
TY  - JOUR
A1  - Goychuk, Igor
T1  - Sensing magnetic fields with magnetosensitive ion channels
JF  - Sensors
N2  - Magnetic nanoparticles are met across many biological species ranging from magnetosensitive bacteria, fishes, bees, bats, rats, birds, to humans. They can be both of biogenetic origin and due to environmental contamination, being either in paramagnetic or ferromagnetic state. The energy of such naturally occurring single-domain magnetic nanoparticles can reach up to 10-20 room k(B)T in the magnetic field of the Earth, which naturally led to supposition that they can serve as sensory elements in various animals. This work explores within a stochastic modeling framework a fascinating hypothesis of magnetosensitive ion channels with magnetic nanoparticles serving as sensory elements, especially, how realistic it is given a highly dissipative viscoelastic interior of living cells and typical sizes of nanoparticles possibly involved.
KW  - magnetic nanoparticles
KW  - ion channels
KW  - viscoelastic effects and anomalous diffusion
KW  - non-exponential statistics
KW  - influence of weak magnetic fields on living systems
Y1  - 2018
U6  - https://doi.org/10.3390/s18030728
SN  - 1424-8220
VL  - 18
IS  - 3
PB  - MDPI
CY  - Basel
ER  -