scholarly journals Inferring transient particle transport dynamics in live cells

2015 ◽  
Vol 12 (9) ◽  
pp. 838-840 ◽  
Author(s):  
Nilah Monnier ◽  
Zachary Barry ◽  
Hye Yoon Park ◽  
Kuan-Chung Su ◽  
Zachary Katz ◽  
...  
Keyword(s):  
Particle Transport ◽  
Live Cells ◽  
Transport Dynamics

scholarly journals Fine particle transport dynamics in response to wood additions in a small agricultural stream

2020 ◽  
Vol 34 (21) ◽  
pp. 4128-4138
Author(s):  
Jennifer Drummond ◽  
Aslan Wright‐Stow ◽  
Paul Franklin ◽  
John Quinn ◽  
Aaron Packman
Keyword(s):  
Particle Transport ◽  
Fine Particle ◽  
Transport Dynamics ◽  
Agricultural Stream

VALIDATING THE DIFFUSION APPROXIMATION THROUGH CONDITIONAL ENTROPIES

2011 ◽  
Vol 25 (06) ◽  
pp. 377-383
Author(s):  
J.-P. RIVET ◽  
F. DEBBASCH
Keyword(s):  
Markov Process ◽  
Invariant Measure ◽  
Diffusion Approximation ◽  
Particle Transport ◽  
Invariant Measures ◽  
Large Range ◽  
Brownian Particle ◽  
Conditional Entropy ◽  
The Real ◽  
Transport Dynamics

The diffusion approximation replaces a real transport dynamics by an approximate stochastic Markov process. It is proposed that, when both dynamics have invariant measures, the conditional entropy of the invariant measure of the real dynamics with respect to the invariant measure of the Markov process be used to assess quantitatively the validity of the approximation. This proposal is tested on particle transport; the diffusion approximation is found to be quite robust, valid for an unexpectedly large range of mass ratios between the solvent and the Brownian particle.

scholarly journals Solute transport in a heterogeneous aquifer: a search for nonlinear deterministic dynamics

2005 ◽  
Vol 12 (2) ◽  
pp. 211-218 ◽  
Author(s):  
B. Sivakumar ◽  
T. Harter ◽  
H. Zhang
Keyword(s):  
Time Series ◽  
Solute Transport ◽  
Particle Transport ◽  
Correlation Dimension ◽  
Transport Processes ◽  
Anisotropy Ratio ◽  
Transport Dynamics ◽  
Heterogeneous Aquifer ◽  
Wide Range ◽  
Correlation Dimension Method

Abstract. The potential use of a nonlinear deterministic framework for understanding the dynamic nature of solute transport processes in subsurface formations is investigated. Time series of solute particle transport in a heterogeneous aquifer medium, simulated using an integrated probability/Markov chain (TP/MC) model, groundwater flow model, and particle transport model, are studied. The correlation dimension method, a popular nonlinear time series analysis technique, is used to identify nonlinear determinism. Sensitivity of the solute transport dynamics to the four hydrostratigraphic parameters involved in the TP/MC model: (1) number of facies; (2) volume proportions of facies; (3) mean lengths (and thereby anisotropy ratio of mean length) of facies; and (4) juxtapositional tendencies (i.e. degree of entropy) among the facies is also studied. The western San Joaquin Valley aquifer system in California is considered as a reference system. The results indicate, in general, the nonlinear deterministic nature of solute transport dynamics (dominantly governed by only a very few variables, on the order of 3), even though more complex behavior is possible under certain (extreme) hydrostratigraphic conditions. The sensitivity analysis reveals: (1) the importance of the hydrostratigraphic parameters (in particular, volume proportions of facies and mean lengths) in representing aquifer heterogeneity; and (2) the ability of the correlation dimension method in capturing the (extent of) complexity of the underlying dynamics. Verification and confirmation of the present results through use of other nonlinear deterministic techniques and assessment of their reliability for a wide range of solute transport scenarios are recommended.

scholarly journals Nuclear Import of Adeno-Associated Viruses Imaged by High-Speed Single-Molecule Microscopy

Viruses ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 167
Author(s):  
Samuel L. Junod ◽  
Jason Saredy ◽  
Weidong Yang
Keyword(s):  
Fluorescence Microscopy ◽  
Single Molecule ◽  
Nuclear Import ◽  
High Speed ◽  
Single Point ◽  
Live Cells ◽  
Nuclear Pore ◽  
Transport Dynamics ◽  
Technical Advances ◽  
Live Cell Microscopy

Understanding the detailed nuclear import kinetics of adeno-associated virus (AAV) through the nuclear pore complex (NPC) is essential for the application of AAV capsids as a nuclear delivery instrument as well as a target for drug development. However, a comprehensive understanding of AAV transport through the sub-micrometer NPCs in live cells calls for new techniques that can conquer the limitations of conventional fluorescence microscopy and electron microscopy. With recent technical advances in single-molecule fluorescence microscopy, we are now able to image the entire nuclear import process of AAV particles and also quantify the transport dynamics of viral particles through the NPCs in live human cells. In this review, we initially evaluate the necessity of single-molecule live-cell microscopy in the study of nuclear import for AAV particles. Then, we detail the application of high-speed single-point edge-excitation sub-diffraction (SPEED) microscopy in tracking the entire process of nuclear import for AAV particles. Finally, we summarize the major findings for AAV nuclear import by using SPEED microscopy.

scholarly journals Assessing and Modelling the Interactions of Instrumented Particles with Bed Surface at Low Transport Conditions

2021 ◽  
Vol 11 (16) ◽  
pp. 7306
Author(s):  
Zaid Alhusban ◽  
Manousos Valyrakis
Keyword(s):  
Sediment Transport ◽  
Turbulent Flows ◽  
Particle Transport ◽  
Particle Density ◽  
Probability Distributions ◽  
Low Cost ◽  
Bed Load ◽  
Transport Dynamics ◽  
Field Deployment ◽  
Near Future

Sediment transport at near threshold to low transport stages (below the continuous transport) can still be affected by flow turbulence and its dynamics can benefit from further comprehensive studies. This study uses an instrumented particle embedded with micro electromechanical sensors (MEMS) to allow tracking the motions and forces acting on it, leading to and during its transport. Instrumented particle transport experiments were carried out at laboratory flume under a range of flow conditions. The probability distributions functions (PDFs) of bed load particle instantaneous velocities, hop distances and associated travel times (measured from start to stop of transport) were obtained for all the performed experiments with varying flow rates and particle density. The modelled distributions are useful and enable a deeper understanding of bed load sediment transport dynamics from a Lagrangian perspective. Furthermore, the results analyzed from the instrumented particle (including the particle’s transport mode) were validated using visual particle tracking methods (top and side cameras). The findings of this study demonstrate that for the range of turbulent flows trialed herein, the instrumented particle can be a useful, accessible, and low-cost tool for obtaining particle transport dynamics, having demonstrated satisfactory potential for field deployment in the near future.

4-dimensional, high-resolution imaging of living cells

1992 ◽  
Vol 50 (1) ◽  
pp. 416-417
Author(s):  
Shinya Inoué
Keyword(s):  
Light Microscope ◽  
Living Cells ◽  
Live Cells ◽  
Video Tape ◽  
Active Living ◽  
High Resolution Imaging ◽  
3 Dimensional ◽  
Dynamic Architecture ◽  
Resolution Imaging ◽  
Disk Memory

This paper reports progress of our effort to rapidly capture, and display in time-lapsed mode, the 3-dimensional dynamic architecture of active living cells and developing embryos at the highest resolution of the light microscope. Our approach entails: (A) real-time video tape recording of through-focal, ultrathin optical sections of live cells at the highest resolution of the light microscope; (B) repeat of A at time-lapsed intervals; (C) once each time-lapsed interval, an image at home focus is recorded onto Optical Disk Memory Recorder (OMDR); (D) periods of interest are selected using the OMDR and video tape records; (E) selected stacks of optical sections are converted into plane projections representing different view angles (±4 degrees for stereo view, additional angles when revolving stereos are desired); (F) analysis using A - D.

Multi-mode light microscopy of microtubule assembly dynamics and chromosome movement in vivo and In vitro

1996 ◽  
Vol 54 ◽  
pp. 730-731
Author(s):  
E. D. Salmon ◽  
J. C. Waters ◽  
C. Waterman-Storer
Keyword(s):  
Imaging System ◽  
Ccd Camera ◽  
Transmitted Light ◽  
Microtubule Assembly ◽  
Live Cells ◽  
Optical Efficiency ◽  
Multiple Band ◽  
Multi Mode

We have developed a multi-mode digital imaging system which acquires images with a cooled CCD camera (Figure 1). A multiple band pass dichromatic mirror and robotically controlled filter wheels provide wavelength selection for epi-fluorescence. Shutters select illumination either by epi-fluorescence or by transmitted light for phase contrast or DIC. Many of our experiments involve investigations of spindle assembly dynamics and chromosome movements in live cells or unfixed reconstituted preparations in vitro in which photodamage and phototoxicity are major concerns. As a consequence, a major factor in the design was optical efficiency: achieving the highest image quality with the least number of illumination photons. This principle applies to both epi-fluorescence and transmitted light imaging modes. In living cells and extracts, microtubules are visualized using X-rhodamine labeled tubulin. Photoactivation of C2CF-fluorescein labeled tubulin is used to locally mark microtubules in studies of microtubule dynamics and translocation. Chromosomes are labeled with DAPI or Hoechst DNA intercalating dyes.

Characterization of a Motile Cellular Domain Arising During the Amoebo-Flagellate Transformation of Physarum Polycephalum

1980 ◽  
Vol 38 ◽  
pp. 552-553
Author(s):  
K.I. Pagh ◽  
M.R. Adelman
Keyword(s):  
Cell Shape ◽  
Physarum Polycephalum ◽  
Slime Mold ◽  
Live Cells ◽  
Cellular Domain

Unicellular amoebae of the slime mold Physarum polycephalum undergo marked changes in cell shape and motility during their conversion into flagellate swimming cells (l). To understand the processes underlying motile activities expressed during the amoebo-flagellate transformation, we have undertaken detailed investigations of the organization, formation and functions of subcellular structures or domains of the cell which are hypothesized to play a role in movement. One focus of our studies is on a structure, termed the “ridge” which appears as a flattened extension of the periphery along the length of transforming cells (Fig. 1). Observations of live cells using Nomarski optics reveal two types of movement in this region:propagation of undulations along the length of the ridge and formation and retraction of filopodial projections from its edge. The differing activities appear to be associated with two characteristic morphologies, illustrated in Fig. 1.

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