Cortical microtubule nucleation can organise the cytoskeleton of Drosophila oocytes to define the anteroposterior axis

Many cells contain non-centrosomal arrays of microtubules (MTs), but the assembly, organisation and function of these arrays are poorly understood. We present the first theoretical model for the non-centrosomal MT cytoskeleton in Drosophila oocytes, in which bicoid and oskar mRNAs become localised to establish the anterior-posterior body axis. Constrained by experimental measurements, the model shows that a simple gradient of cortical MT nucleation is sufficient to reproduce the observed MT distribution, cytoplasmic flow patterns and localisation of oskar and naive bicoid mRNAs. Our simulations exclude a major role for cytoplasmic flows in localisation and reveal an organisation of the MT cytoskeleton that is more ordered than previously thought. Furthermore, modulating cortical MT nucleation induces a bifurcation in cytoskeletal organisation that accounts for the phenotypes of polarity mutants. Thus, our three-dimensional model explains many features of the MT network and highlights the importance of differential cortical MT nucleation for axis formation.

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Numerical Simulation of Vertical Forced Plume in a Crossflow of Stably Stratified Fluid

Journal of Fluids Engineering ◽

10.1115/1.2817325 ◽

1995 ◽

Vol 117 (4) ◽

pp. 696-705 ◽

Cited By ~ 12

Author(s):

Robert R. Hwang ◽

T. P. Chiang

Keyword(s):

Numerical Simulation ◽

Numerical Model ◽

Cross Section ◽

Three Dimensional ◽

Experimental Measurements ◽

Secondary Vortex ◽

Dimensional Model ◽

Three Dimensional Model ◽

Vortex Pairs ◽

Plume Flows

In this study, an investigation using a three-dimensional numerical model, which treats conservation of mass, momentum, and salinity simultaneously, was carried out to study the character of a vertical forced plume in a uniform cross-stream of stably linear stratified environment. A k-ε turbulence model was used to simulate the turbulent phenomena and close the solving problem. The performance of the three-dimensional model is evaluated by comparison of the numerical results with some available experimental measurements. Results indicate that the numerical computation simulates satisfactorily the plume behavior in a stratified crossflow. The secondary vortex pairs in the cross section induced by the primary one change as the plume flows downstream. This denotes the transformation of entrainment mechanism in stratified crossflow.

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Some observations on the structure and function of the dinoflagellate pusule

Canadian Journal of Botany ◽

10.1139/b87-098 ◽

1987 ◽

Vol 65 (4) ◽

pp. 736-744 ◽

Cited By ~ 22

Author(s):

M. Emilia Klut ◽

T. Bisalputra ◽

N. J. Antia

Keyword(s):

Horseradish Peroxidase ◽

Cytochalasin B ◽

Three Dimensional ◽

Structure And Function ◽

Cationized Ferritin ◽

Dimensional Model ◽

Three Dimensional Model ◽

Prorocentrum Micans ◽

Physicochemical Factors ◽

And Function

The pusules of an armoured dinoflagellate (Prorocentrum micans) and an unarmoured species (Amphidinium carterae) were examined for effects of certain physicochemical factors, physiological inhibitors, and cytological markers. Fluxes in both salinity and temperature caused pusular size changes, while colchicine, cytochalasin B, and pH changes (in the range 6.0–8.0) had little or no effect. The treatment with solutions of horseradish peroxidase, cationized ferritin, and lectins indicated uptake of these macromolecules via the flagellar canal into the pusules of both dinoflagellates. A three-dimensional model is proposed for the A. carterae pusule based on sequential sections examined by TEM. It is suggested that a fibrillar collar system, in conjunction with the flagellar beating, plays a crucial role in regulating the flow of materials in and out of the pusule. The overall results suggest a multiple function for the dinoflagellate pusule, including osmoregulation, macromolecule uptake, and probably, secretion.

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Establishment of the three-dimensional model of the nonwoven structure with fiber scale based on the GAN algorithm

Textile Research Journal ◽

10.1177/00405175211067280 ◽

2021 ◽

pp. 004051752110672

Author(s):

Jiang Wang ◽

Qianqian Shi ◽

Nicholus Tayari Akankwasa ◽

Yuze Zhang ◽

Jun Wang

Keyword(s):

Simulation Analysis ◽

Special Functions ◽

Three Dimensional ◽

Nonwoven Fabric ◽

Generation Model ◽

Diffusion Experiment ◽

Two Dimensional ◽

Dimensional Model ◽

Three Dimensional Model ◽

And Function

The structure of nonwovens gives special functions, and the establishment of the structure model has important reference significance for the realization of functions. In this work, the two-dimensional configuration of polyester fibers in a spunlaced nonwoven fabric was extracted, and the configurational feature points of 2500 fibers were obtained. Combined with the generative adversarial nets algorithm, the generation model of the two-dimensional configuration of fibers was proposed after learning the configuration feature of 2500 fibers. Based on the assumption that the fibers are randomly distributed in the nonwoven fabric, we established a three-dimensional model of the spunlaced nonwoven fabric on the fiber scale using ABAQUS software. In addition, the water diffusion experiment and simulation were carried out to visualize the diffusion process of a water droplet in the nonwoven fabric, verifying the accuracy of the model. This method provides a novel idea for the modeling of textile structure on the fiber scale, which can be regarded as a model basis for the subsequent simulation analysis and function research.

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