scholarly journals Local Analysis of Heterogeneous Intracellular Transport: Slow and Fast Moving Endosomes

Entropy ◽  
2021 ◽  
Vol 23 (8) ◽  
pp. 958
Author(s):  
Nickolay Korabel ◽  
Daniel Han ◽  
Alessandro Taloni ◽  
Gianni Pagnini ◽  
Sergei Fedotov ◽  
...  
Keyword(s):  
Diffusion Coefficients ◽  
Fast Moving ◽  
Intracellular Transport ◽  
Single Particle Tracking ◽  
Local Analysis ◽  
Exponential Distributions ◽  
Auto Correlation ◽  
Slow Moving ◽  
The Mean ◽  
Power Law Distributions

Trajectories of endosomes inside living eukaryotic cells are highly heterogeneous in space and time and diffuse anomalously due to a combination of viscoelasticity, caging, aggregation and active transport. Some of the trajectories display switching between persistent and anti-persistent motion, while others jiggle around in one position for the whole measurement time. By splitting the ensemble of endosome trajectories into slow moving subdiffusive and fast moving superdiffusive endosomes, we analyzed them separately. The mean squared displacements and velocity auto-correlation functions confirm the effectiveness of the splitting methods. Applying the local analysis, we show that both ensembles are characterized by a spectrum of local anomalous exponents and local generalized diffusion coefficients. Slow and fast endosomes have exponential distributions of local anomalous exponents and power law distributions of generalized diffusion coefficients. This suggests that heterogeneous fractional Brownian motion is an appropriate model for both fast and slow moving endosomes. This article is part of a Special Issue entitled: “Recent Advances In Single-Particle Tracking: Experiment and Analysis” edited by Janusz Szwabiński and Aleksander Weron.

scholarly journals Reconstruction of Diffusion Coefficients and Power Exponents from Single Lagrangian Trajectories

Fluids ◽  
2021 ◽  
Vol 6 (3) ◽  
pp. 111
Author(s):  
Leonid M. Ivanov ◽  
Collins A. Collins ◽  
Tetyana Margolina
Keyword(s):  
Black Sea ◽  
Diffusion Coefficients ◽  
Current System ◽  
Mean Square Displacement ◽  
California Current ◽  
The Black Sea ◽  
Mean Square ◽  
California Current System ◽  
The Mean ◽  
Non Gaussian

Using discrete wavelets, a novel technique is developed to estimate turbulent diffusion coefficients and power exponents from single Lagrangian particle trajectories. The technique differs from the classical approach (Davis (1991)’s technique) because averaging over a statistical ensemble of the mean square displacement (<X2>) is replaced by averaging along a single Lagrangian trajectory X(t) = {X(t), Y(t)}. Metzler et al. (2014) have demonstrated that for an ergodic (for example, normal diffusion) flow, the mean square displacement is <X2> = limT→∞τX2(T,s), where τX2 (T, s) = 1/(T − s) ∫0T−s(X(t+Δt) − X(t))2 dt, T and s are observational and lag times but for weak non-ergodic (such as super-diffusion and sub-diffusion) flows <X2> = limT→∞≪τX2(T,s)≫, where ≪…≫ is some additional averaging. Numerical calculations for surface drifters in the Black Sea and isobaric RAFOS floats deployed at mid depths in the California Current system demonstrated that the reconstructed diffusion coefficients were smaller than those calculated by Davis (1991)’s technique. This difference is caused by the choice of the Lagrangian mean. The technique proposed here is applied to the analysis of Lagrangian motions in the Black Sea (horizontal diffusion coefficients varied from 105 to 106 cm2/s) and for the sub-diffusion of two RAFOS floats in the California Current system where power exponents varied from 0.65 to 0.72. RAFOS float motions were found to be strongly non-ergodic and non-Gaussian.

Diffusion of Zinc in Two-Phase Mg-Al Alloy

2007 ◽  
Vol 263 ◽  
pp. 189-194
Author(s):  
Ivo Stloukal ◽  
Jiří Čermák
Keyword(s):  
Diffusion Coefficient ◽  
Diffusion Coefficients ◽  
Effective Diffusion ◽  
Residual Activity ◽  
Diffusion Path ◽  
Al Alloy ◽  
Serial Sectioning ◽  
Two Phase ◽  
Interphase Boundaries ◽  
The Mean

Coefficient of 65Zn heterodiffusion in Mg17Al12 intermetallic and in eutectic alloy Mg - 33.4 wt. % Al was measured in the temperature region 598 – 698 K using serial sectioning and residual activity methods. Diffusion coefficient of 65Zn in the intermetallic can be written as DI = 1.7 × 10-2 m2 s-1 exp (-155.0 kJ mol-1 / RT). At temperatures T ≥ 648 K, where the mean diffusion path was greater than the mean interlamellar distance in the eutectic, the effective diffusion coefficient Def = 2.7 × 10-2 m2 s-1 exp (-155.1 kJ mol-1 / RT) was evaluated. At two lower temperatures, the diffusion coefficients 65Zn in interphase boundaries were estimated: Db (623 K) = 1.6 × 10-12 m2 s-1 and Db (598 K) = 4.4 × 10-13 m2 s-1.

scholarly journals Neuronal receptors display cytoskeleton-independent directed motion on the plasma membrane

2018 ◽  
Author(s):  
R. D. Taylor ◽  
M. Heine ◽  
N. J. Emptage ◽  
L. C. Andreae
Keyword(s):  
Plasma Membrane ◽  
Neuronal Activity ◽  
Particle Tracking ◽  
Hippocampal Neurons ◽  
Intracellular Transport ◽  
Transmembrane Proteins ◽  
Single Particle Tracking ◽  
Directed Motion ◽  
Surface Movement ◽  
Transport Vesicles

AbstractDirected transport of transmembrane proteins is generally believed to occur via intracellular transport vesicles. However, using single particle tracking in rat hippocampal neurons with a pH-sensitive quantum dot probe which specifically reports surface movement of receptors, we have identified a subpopulation of neuronal EphB2 receptors that exhibit directed motion between synapses within the plasma membrane itself. This receptor movement occurs independently of the cytoskeleton but is dependent on cholesterol and is regulated by neuronal activity.

scholarly journals Subtle changes in crosslinking drive diverse anomalous transport characteristics in actin-microtubule networks

2020 ◽  
Author(s):  
Sylas Anderson ◽  
Jonathan Garamella ◽  
Ryan McGorty ◽  
Rae Robertson-Anderson
Keyword(s):  
Intracellular Transport ◽  
Single Particle Tracking ◽  
Anomalous Transport ◽  
Brownian Diffusion ◽  
Complex Environments ◽  
Materials Engineering ◽  
Microtubule Networks ◽  
Non Gaussian ◽  
Fluid Rheology ◽  
The Impact

Abstract Anomalous diffusion in crowded and complex environments is widely studied due to its importance in intracellular transport, fluid rheology and materials engineering. Specifically, diffusion through the cytoskeleton, a network comprised of semiflexible actin filaments and rigid microtubules that interact both sterically and via crosslinking, plays a principal role in viral infection, vesicle transport and targeted drug delivery. Here, we elucidate the impact of crosslinking on particle diffusion in composites of actin and microtubules with actin-actin, microtubule-microtubule and actin-microtubule crosslinking. We analyze a suite of complementary transport metrics by coupling single-particle tracking and differential dynamic microscopy. Using these orthogonal techniques, we find that particles display non-Gaussian and non-ergodic subdiffusion that is markedly enhanced by cytoskeletal crosslinking of any type, which we attribute to suppressed microtubule mobility. However, the extent to which transport deviates from normal Brownian diffusion depends strongly on the crosslinking motif – with actin-microtubule crosslinking inducing the most pronounced anomalous characteristics – due to increased actin fluctuation heterogeneity. Our results reveal that subtle changes to actin-microtubule interactions can have dramatic impacts on diffusion in the cytoskeleton, and suggest that less mobile and more locally heterogeneous networks lead to more strongly anomalous transport.

scholarly journals Analisis Industri Retail Nasional

Humaniora ◽  
2011 ◽  
Vol 2 (2) ◽  
pp. 1309
Author(s):  
Handy Martinus
Keyword(s):  
Fast Moving ◽  
Retail Industry ◽  
Global Crisis ◽  
Revenue Growth ◽  
Research Material ◽  
Slow Moving ◽  
Document Review

Fast moving in retail industry is the latest trading industry in trading chain. The study is to identify the condition of retail industry in Indonesia. This uses normative juridical approach. The research material is gathered by literature or document review. The analysis for modern retail industry is conducted through qualitative, thus explaining law material gathered from library being selected, arranging systematically, and finally getting conclusion figured to answer problems related to the rules for monopoly and dysfunction business competition in retail industry. The study result showed that modern market, which so far having a good performance, will have challenges. One biggest challenge is the potential for slow-moving revenue growth as the effects of slow-moving economic caused by global crisis.  

scholarly journals Metode FSN Analysis Dan Implementasinya Pada Desain Sistem Informasi Pergudangan

2021 ◽  
Vol 15 (1) ◽  
pp. 60
Author(s):  
Amri Yanuar ◽  
Marwanto Rahmatuloh ◽  
Ilman Mutaqien
Keyword(s):  
Fast Moving ◽  
Order Picking ◽  
Bottle Neck ◽  
Slow Moving

Operasional gudang memiliki berbagai aktivitas inti yang saling berkaitan satu dengan yang lainnya, seperti aktivitas receiving, storage, dan picking. Aktivitas inti ini atau yang biasa disebut inbound dan outbound harus dikerjakan dalam waktu yang singkat dan meminimalisir tingkat kesalahan agar tidak mengganggu keberlangsungan alur masuk dan keluarnya barang di gudang. Beberapa hal yang dapat mengganggu aliran barang di gudang di antaranya adalah terjadinya bottle neck di area receiving, waktu proses pencarian barang yang lama, dan 70% waktu proses order picking di bawah waktu standar. Permasalahan-permasalahan ini terjadi salah satunya dikarenakan pengelolaan barang di gudang masih manual atau belum menggunakan sistem informasi. Tujuan dari penelitian ini adalah merancang sistem informasi untuk membantu operasional gudang guna meminimalisir kesalahan-kesalahan yang dapat mengganggu aliran masuka dan keluarnya barang dari gudang, dengan menggunakan pendekatan FSN Analysis. Hasil dari pengolahan data menggunakan FSN Analysis ini, dapat membantu dalam mengetahui produk-produk yang masuk kedalam kategori fast moving, slow moving, dan non-moving.

Radio Observations of a Massive, Slow-Moving Ejection of Coronal Material

1978 ◽  
Vol 3 (4) ◽  
pp. 249-250 ◽  
Author(s):  
K. V. Sheridan ◽  
B. V. Jackson ◽  
D. J. McLean ◽  
G. A. Dulk
Keyword(s):  
White Light ◽  
Fast Moving ◽  
Radio Bursts ◽  
Type Ii ◽  
Radio Observations ◽  
Quiet Sun ◽  
Slow Moving

Studies of coronal transients observed in white-light (Gosling et al., 1976) have shown that fast-moving events (≤ 400 km s-1) are closely associated with flares and with type II and IV radio bursts while slow-moving events are not. We now report the first detection of the radio counterpart of a slow-moving transient. The event of 1974 January 21 is shown to be visible on maps of the quiet Sun made at a frequency of 80 MHz.

scholarly journals Specific features of eddy turbulence in the turbopause region

2014 ◽  
Vol 32 (4) ◽  
pp. 431-442 ◽  
Author(s):  
M. N. Vlasov ◽  
M. C. Kelley
Keyword(s):  
Diffusion Coefficient ◽  
Heat Transport ◽  
Diffusion Coefficients ◽  
Transport Coefficient ◽  
Molecular Diffusion ◽  
Eddy Diffusion ◽  
Cooling Rates ◽  
Eddy Diffusion Coefficient ◽  
Eddy Heat Transport ◽  
The Mean

Abstract. The turbopause region is characterized by transition from the mean molecular mass (constant with altitude) to the mean mass (dependent on altitude). The former is provided by eddy turbulence, and the latter is induced by molecular diffusion. Competition between these processes provides the transition from the homosphere to the heterosphere. The turbopause altitude can be defined by equalizing the eddy and molecular diffusion coefficients and can be located in the upper mesosphere or the lower thermosphere. The height distributions of chemical inert gases very clearly demonstrate the transition from turbulent mixing to the diffusive separation of these gases. Using the height distributions of the chemical inert constituents He, Ar, and N2 given by the MSIS-E-90 model and the continuity equations, the height distribution of the eddy diffusion coefficient in the turbopause region can be inferred. The eddy diffusion coefficient always strongly reduces in the turbopause region. According to our results, eddy turbulence above its peak always cools the atmosphere. However, the cooling rates calculated with the eddy heat transport coefficient equaled to the eddy diffusion coefficient were found to be much larger than the cooling rates corresponding to the neutral temperatures given by the MSIS-E-90 model. The same results were obtained for the eddy diffusion coefficients inferred from different experimental data. The main cause of this large cooling is the very steep negative gradient of the eddy heat transport coefficient, which is equal to the eddy diffusion coefficient if uniform turbulence takes place in the turbopause region. Analysis of wind shear shows that localized turbulence can develop in the turbopause region. In this case, eddy heat transport is not so effective and the strong discrepancy between cooling induced by eddy turbulence and cooling corresponding to the temperature given by the MSIS-E-90 model can be removed.

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