TY  - JOUR
A1  - Metzler, Ralf
T1  - Superstatistics and non-Gaussian diffusion
JF  - The European physical journal special topics
N2  - Brownian motion and viscoelastic anomalous diffusion in homogeneous environments are intrinsically Gaussian processes. In a growing number of systems, however, non-Gaussian displacement distributions of these processes are being reported. The physical cause of the non-Gaussianity is typically seen in different forms of disorder. These include, for instance, imperfect "ensembles" of tracer particles, the presence of local variations of the tracer mobility in heteroegenous environments, or cases in which the speed or persistence of moving nematodes or cells are distributed. From a theoretical point of view stochastic descriptions based on distributed ("superstatistical") transport coefficients as well as time-dependent generalisations based on stochastic transport parameters with built-in finite correlation time are invoked. After a brief review of the history of Brownian motion and the famed Gaussian displacement distribution, we here provide a brief introduction to the phenomenon of non-Gaussianity and the stochastic modelling in terms of superstatistical and diffusing-diffusivity approaches.
KW  - Brownian diffusion
KW  - anomalous diffusion
KW  - dynamics
KW  - kinetic-theory
KW  - models
KW  - motion
KW  - nanoparticles
KW  - nonergodicity
KW  - statistics
KW  - subdiffusion
Y1  - 2020
U6  - https://doi.org/10.1140/epjst/e2020-900210-x
SN  - 1951-6355
SN  - 1951-6401
VL  - 229
IS  - 5
SP  - 711
EP  - 728
PB  - Springer
CY  - Heidelberg
ER  - 
TY  - JOUR
A1  - Norregaard, Kamilla
A1  - Metzler, Ralf
A1  - Ritter, Christine M.
A1  - Berg-Sorensen, Kirstine
A1  - Oddershede, Lene Broeng
T1  - Manipulation and Motion of Organelles and Single Molecules in Living Cells
JF  - Chemical reviews
N2  - The biomolecule is among the most important building blocks of biological systems, and a full understanding of its function forms the scaffold for describing the mechanisms of higher order structures as organelles and cells. Force is a fundamental regulatory mechanism of biomolecular interactions driving many cellular processes. The forces on a molecular scale are exactly in the range that can be manipulated and probed with single molecule force spectroscopy. The natural environment of a biomolecule is inside a living cell, hence, this is the most relevant environment for probing their function. In vivo studies are, however, challenged by the complexity of the cell. In this review, we start with presenting relevant theoretical tools for analyzing single molecule data obtained in intracellular environments followed by a description of state-of-the art visualization techniques. The most commonly used force spectroscopy techniques, namely optical tweezers, magnetic tweezers, and atomic force microscopy, are described in detail, and their strength and limitations related to in vivo experiments are discussed. Finally, recent exciting discoveries within the field of in vivo manipulation and dynamics of single molecule and organelles are reviewed.
Y1  - 2017
U6  - https://doi.org/10.1021/acs.chemrev.6b00638
SN  - 0009-2665
SN  - 1520-6890
VL  - 117
IS  - 5
SP  - 4342
EP  - 4375
PB  - American Chemical Society
CY  - Washington
ER  -