scholarly journals Coloring Single Nanoparticle Trajectory in Live Cell with its Own History: a Presuppositionless Preprocessing Approach

2019 ◽  
Author(s):  
Hansen Zhao ◽  
Zhenrong Huang ◽  
Feng Ge ◽  
Xiangjun Shi ◽  
Bin Xiong ◽  
...  
Keyword(s):  
Single Particle ◽  
Complex Dynamics ◽  
Live Cell ◽  
State Transitions ◽  
Human Beings ◽  
Global Pattern ◽  
Model Free ◽  
Mechanical Models ◽  
Data Points ◽  
Underlying Mechanisms

AbstractAnalyzing single particle trajectories is a prominent issue in understanding complex dynamics such as nanoparticle-cell interactions. Existing methods treat data points as isolated “atoms” and use predefined mechanical models to “frame” their complicated relationship. Herein, we propose a “historical evolution” based model-free strategy. It allows spatiotemporal heterogeneity embedded in a trajectory to self-emerge as consecutive colored segments before any model assumption, provide both an overall picture and local state transitions on the particle movement with minimum information loss, and inspire further model-based investigation. We demonstrate with simulations and experiments that the underlying mechanisms of various time-series and motion states of single nanoparticles on live cell membranes could all be revealed successfully. Since complexity studies at different levels of molecules, particles, cells, human beings, vehicles, and even stars could all be reduced to analyzing spatiotemporal trajectories of “single particles”, this presuppositionless approach will help fundamental researches on many important systems.Impact StatementA preprocessing strategy for single particle trajectory analysis is established by providing an intuitive global pattern from “historical experiences” of the particle without predefining any mechanical models.

scholarly journals Trends in the Control of Hexapod Robots: A Survey

Robotics ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 100
Author(s):  
Joana Coelho ◽  
Fernando Ribeiro ◽  
Bruno Dias ◽  
Gil Lopes ◽  
Paulo Flores
Keyword(s):  
Control System ◽  
Literature Review ◽  
Systematic Literature Review ◽  
Traditional Approach ◽  
Robotic Manipulators ◽  
Static Stability ◽  
Human Beings ◽  
Complex Environments ◽  
Model Free ◽  
Mechanical Models

The static stability of hexapods motivates their design for tasks in which stable locomotion is required, such as navigation across complex environments. This task is of high interest due to the possibility of replacing human beings in exploration, surveillance and rescue missions. For this application, the control system must adapt the actuation of the limbs according to their surroundings to ensure that the hexapod does not tumble during locomotion. The most traditional approach considers their limbs as robotic manipulators and relies on mechanical models to actuate them. However, the increasing interest in model-free models for the control of these systems has led to the design of novel solutions. Through a systematic literature review, this paper intends to overview the trends in this field of research and determine in which stage the design of autonomous and adaptable controllers for hexapods is.

scholarly journals Sensitivity of the Single Particle Soot Photometer to different black carbon types

2012 ◽  
Vol 5 (5) ◽  
pp. 1031-1043 ◽  
Author(s):  
M. Laborde ◽  
P. Mertes ◽  
P. Zieger ◽  
J. Dommen ◽  
U. Baltensperger ◽  
...  
Keyword(s):  
Black Carbon ◽  
Single Particle ◽  
Diesel Exhaust ◽  
Mass Analyzer ◽  
Human Beings ◽  
Radiative Balance ◽  
Ambient Particles ◽  
Fullerene Soot ◽  
Wood Burning ◽  
Incomplete Removal

Abstract. Black carbon (BC) is now mainly of anthropogenic origin. It is the dominant light absorbing component of atmospheric aerosols, playing an important role in the earth's radiative balance and therefore relevant to climate change studies. In addition, BC is known to be harmful to human beings making it relevant to policy makers. Nevertheless, the measurement of BC remains biased by the instrument-based definition of BC. The Single Particle Soot Photometer (SP2), allows the measurement of the refractory BC (rBC) mass of individual particles using laser-induced incandescence. However, the SP2 needs an empirical calibration to retrieve the rBC mass from the incandescence signal and the sensitivity of the SP2 differs between different BC types. Ideally, for atmospheric studies, the SP2 should be calibrated using ambient particles containing a known mass of ambient rBC. However, such "ambient BC" calibration particles cannot easily be obtained and thus commercially available BC particles are commonly used for SP2 calibration instead. In this study we tested the sensitivity of the SP2 to different BC types in order to characterize the potential error introduced by using non-ambient BC for calibration. The sensitivity of the SP2 was determined, using an aerosol particle mass analyzer, for rBC from thermodenuded diesel exhaust, wood burning exhaust and ambient particles as well as for commercially available products: Aquadag® and fullerene soot. Thermodenuded, fresh diesel exhaust has been found to be ideal for SP2 calibration for two reasons. First, the small amount of non-BC matter upon emission reduces the risk of bias due to incomplete removal of non-BC matter and second, it is considered to represent atmospheric rBC in urban locations where diesel exhaust is the main source of BC. The SP2 was found to be up to 16% less sensitive to rBC from thermodenuded ambient particles (≤15 fg) than rBC from diesel exhaust, however, at least part of this difference can be explained by incomplete removal of non-refractory components in the thermodenuder. The amount of remaining non-refractory matter was estimated to be below 30% by mass, according to a comparison of the scattering cross sections of the whole particles with that of the pure BC cores. The SP2 sensitivity to rBC from wood burning exhaust agrees with the SP2 sensitivity to rBC from diesel exhaust within an error of less than 14% (≤40 fg). If, due to experimental restrictions, diesel exhaust cannot be used, untreated fullerene soot was found to give an SP2 calibration curve similar to diesel exhaust and ambient rBC (within ±10% for a rBC mass ≤15 fg) and is therefore recommended although two different batches differed by ~14% between themselves. In addition, the SP2 was found to be up to 40% more sensitive to Aquadag® than to diesel exhaust rBC. Therefore Aquadag® cannot be recommended for atmospheric application without accounting for the sensitivity difference. These findings for fullerene soot and Aquadag® confirm results from previous literature.

scholarly journals Lysosome Mobility Probed with Live Cell Imaging and Single Particle Tracking

2013 ◽  
Vol 104 (2) ◽  
pp. 651a
Author(s):  
Debjyoti Bandyopadhyay ◽  
Youngeun J. Kim ◽  
Jairo Zapata ◽  
Christine K. Payne
Keyword(s):  
Particle Tracking ◽  
Single Particle ◽  
Live Cell Imaging ◽  
Cell Imaging ◽  
Single Particle Tracking ◽  
Live Cell

scholarly journals Tracking single particle rotation: probing dynamics in four dimensions

2015 ◽  
Vol 7 (17) ◽  
pp. 7020-7028 ◽  
Author(s):  
S. M. Anthony ◽  
Y. Yu
Keyword(s):  
Temporal Resolution ◽  
Single Particle ◽  
Complex Dynamics ◽  
Biological Processes ◽  
Direct Visualization ◽  
Small Particles ◽  
Particle Rotation ◽  
Four Dimensions ◽  
Powerful Approach

Direct visualization and tracking of small particles at high spatial and temporal resolution provides a powerful approach to probing complex dynamics and interactions in chemical and biological processes.

scholarly journals Modelling the role of LHCII-LHCII, PSII-LHCII and PSI-LHCII interactions in state transitions

2019 ◽  
Author(s):  
W. H. J. Wood ◽  
M. P. Johnson
Keyword(s):  
Monte Carlo ◽  
Protein Complex ◽  
Thylakoid Membrane ◽  
State Transition ◽  
Complex Dynamics ◽  
Light Harvesting ◽  
State Transitions ◽  
Antenna Size ◽  
Light Harvesting Antenna ◽  
Novel Algorithm

AbstractThe light-dependent reactions of photosynthesis take place in the plant chloroplast thylakoid membrane, a complex three-dimensional structure divided into the stacked grana and unstacked stromal lamellae domains. Plants regulate the macro-organization of photosynthetic complexes within the thylakoid membrane to adapt to changing environmental conditions and avoid oxidative stress. One such mechanism is the state transition which regulates photosynthetic light harvesting and electron transfer. State transitions are driven by changes in the phosphorylation of light harvesting antenna complex II (LHCII), which cause a decrease in grana diameter and stacking, a decreased energetic connectivity between photosystem II (PSII) reaction centres and an increase in the relative LHCII antenna size of photosystem I (PSI) compared to PSII. Phosphorylation is believed to drive these changes by weakening the intra-membrane lateral PSII-LHCII and LHCII-LHCII interactions and the inter-membrane stacking interactions between these complexes, while simultaneously increasing the affinity of LHCII for PSI. We investigated the relative roles and contributions of these three types of interaction to state transitions using a lattice-based model of the thylakoid membrane based on existing structural data, developing a novel algorithm to simulate protein complex dynamics. Monte Carlo simulations revealed that state transitions are unlikely to lead to a large-scale migration of LHCII from the grana to the stromal lamellae. Instead, the increased light harvesting capacity of PSI is largely due to the more efficient recruitment of LHCII already residing in the stromal lamellae into PSI-LHCII supercomplexes upon its phosphorylation. Likewise, the increased light harvesting capacity of PSII upon dephosphorylation was found to be driven by a more efficient recruitment of LHCII already residing in the grana into functional PSII-LHCII clusters, primarily driven by lateral interactions.Statement of significanceFor photosynthesis to operate at maximum efficiency the activity of the light-driven chlorophyll-protein complexes, photosystems I and II (PSI and PSII) must be fine-tuned to environmental conditions. Plants achieve this balance through a regulatory mechanism known as the state transition, which modulates the relative light-harvesting antenna size and therefore excitation rate of each photosystem. State transitions are driven by changes in the extent of the phosphorylation of light harvesting complex II (LHCII), which modulate the interactions between PSI, PSII and LHCII. Here we developed a novel algorithm to simulate protein complex dynamics and then ran Monte Carlo simulations to understand how these interactions cooperate to affect the organization of the photosynthetic membrane and bring about state transitions.

scholarly journals Single-particle states vs. collective modes: friends or enemies ?

2018 ◽  
Vol 178 ◽  
pp. 02003 ◽  
Author(s):  
T. Otsuka ◽  
Y. Tsunoda ◽  
T. Togashi ◽  
N. Shimizu ◽  
T. Abe
Keyword(s):  
Single Particle ◽  
Collective Motion ◽  
Collective Mode ◽  
Self Organization ◽  
Collective Modes ◽  
Particle State ◽  
Nuclear Forces ◽  
Atomic Nuclei ◽  
Many Body Systems ◽  
Underlying Mechanisms

The quantum self-organization is introduced as one of the major underlying mechanisms of the quantum many-body systems. In the case of atomic nuclei as an example, two types of the motion of nucleons, single-particle states and collective modes, dominate the structure of the nucleus. The collective mode arises as the balance between the effect of the mode-driving force (e.g., quadrupole force for the ellipsoidal deformation) and the resistance power against it. The single-particle energies are one of the sources to produce such resistance power: a coherent collective motion is more hindered by larger spacings between relevant single particle states. Thus, the single-particle state and the collective mode are “enemies” against each other. However, the nuclear forces are rich enough so as to enhance relevant collective mode by reducing the resistance power by changing single-particle energies for each eigenstate through monopole interactions. This will be verified with the concrete example taken from Zr isotopes. Thus, the quantum self-organization occurs: single-particle energies can be self-organized by (i) two quantum liquids, e.g., protons and neutrons, (ii) monopole interaction (to control resistance). In other words, atomic nuclei are not necessarily like simple rigid vases containing almost free nucleons, in contrast to the naïve Fermi liquid picture. Type II shell evolution is considered to be a simple visible case involving excitations across a (sub)magic gap. The quantum self-organization becomes more important in heavier nuclei where the number of active orbits and the number of active nucleons are larger.

scholarly journals Learning Output Reference Model Tracking for Higher-Order Nonlinear Systems with Unknown Dynamics

Algorithms ◽  
2019 ◽  
Vol 12 (6) ◽  
pp. 121 ◽  
Author(s):  
Mircea-Bogdan Radac ◽  
Timotei Lala
Keyword(s):  
Nonlinear Systems ◽  
State Feedback ◽  
Reference Model ◽  
The State ◽  
State Transitions ◽  
Practical Implementation ◽  
General Function ◽  
State Action ◽  
Model Free ◽  
Continuous State

This work suggests a solution for the output reference model (ORM) tracking control problem, based on approximate dynamic programming. General nonlinear systems are included in a control system (CS) and subjected to state feedback. By linear ORM selection, indirect CS feedback linearization is obtained, leading to favorable linear behavior of the CS. The Value Iteration (VI) algorithm ensures model-free nonlinear state feedback controller learning, without relying on the process dynamics. From linear to nonlinear parameterizations, a reliable approximate VI implementation in continuous state-action spaces depends on several key parameters such as problem dimension, exploration of the state-action space, the state-transitions dataset size, and a suitable selection of the function approximators. Herein, we find that, given a transition sample dataset and a general linear parameterization of the Q-function, the ORM tracking performance obtained with an approximate VI scheme can reach the performance level of a more general implementation using neural networks (NNs). Although the NN-based implementation takes more time to learn due to its higher complexity (more parameters), it is less sensitive to exploration settings, number of transition samples, and to the selected hyper-parameters, hence it is recommending as the de facto practical implementation. Contributions of this work include the following: VI convergence is guaranteed under general function approximators; a case study for a low-order linear system in order to generalize the more complex ORM tracking validation on a real-world nonlinear multivariable aerodynamic process; comparisons with an offline deep deterministic policy gradient solution; implementation details and further discussions on the obtained results.

scholarly journals Live‐cell imaging of octaarginine‐modified polymer dots via single particle tracking

2019 ◽  
Vol 52 (2) ◽  
pp. e12556 ◽  
Author(s):  
Yao Luo ◽  
Yuping Han ◽  
Xingjie Hu ◽  
Min Yin ◽  
Changfeng Wu ◽  
...  
Keyword(s):  
Particle Tracking ◽  
Single Particle ◽  
Live Cell Imaging ◽  
Cell Imaging ◽  
Single Particle Tracking ◽  
Live Cell ◽  
Modified Polymer ◽  
Polymer Dots
Sign in / Sign up

Export Citation Format

Share Document