Numerical Evaluation of the Size-Dependent Elastic Properties of Cellular Polymers

2017 ◽  
Vol 140 (1) ◽  
Author(s):  
Gurudutt Chandrashekar ◽  
Chung-Souk Han
Keyword(s):  
Relative Density ◽  
Cell Size ◽  
Elastic Properties ◽  
Numerical Evaluation ◽  
Elastic Moduli ◽  
Size Dependence ◽  
Experimental Studies ◽  
Length Scale ◽  
Cellular Solid ◽  
Size Dependent

Several experimental studies have revealed that the size-dependent deformation in polymers at nano- to micro-meter length scales is significantly associated with elastic deformation. Such size-dependent deformation in polymers is expected to affect the in-plane macroscopic elastic properties of cellular polymers with micrometer-sized cells. A finite element (FE) formulation of a higher-order elasticity theory is applied to evaluate the in-plane macroscopic elastic properties of different polymer cellular geometries by varying the cell size from the macroscopic to micron length scale. For a given relative density of the cellular solid, a reduction in the cell size from the macroscopic to micron length scale resulted in geometry-specific variations in the in-plane macroscopic elastic moduli and Poisson's ratios. Furthermore, an increase in the relative density for a given cell size revealed variations in the size dependence of the elastic properties. The size dependence of elastic properties is interpreted based on the influence of rotation gradients with varying cell size of the cellular solid. Also, the evaluated size-dependent elastic properties are compared with the available analytical solutions from the literature.

Spindle scaling mechanisms

2020 ◽  
Vol 64 (2) ◽  
pp. 383-396
Author(s):  
Lara K. Krüger ◽  
Phong T. Tran
Keyword(s):  
Cell Size ◽  
Spindle Assembly ◽  
Dependent Manner ◽  
Post Translational Modification ◽  
Size Dependent ◽  
A Cell ◽  
Chromosome Separation ◽  
Spindle Elongation ◽  
Protein Gradients ◽  
Spindle Structure

Abstract The mitotic spindle robustly scales with cell size in a plethora of different organisms. During development and throughout evolution, the spindle adjusts to cell size in metazoans and yeast in order to ensure faithful chromosome separation. Spindle adjustment to cell size occurs by the scaling of spindle length, spindle shape and the velocity of spindle assembly and elongation. Different mechanisms, depending on spindle structure and organism, account for these scaling relationships. The limited availability of critical spindle components, protein gradients, sequestration of spindle components, or post-translational modification and differential expression levels have been implicated in the regulation of spindle length and the spindle assembly/elongation velocity in a cell size-dependent manner. In this review, we will discuss the phenomenon and mechanisms of spindle length, spindle shape and spindle elongation velocity scaling with cell size.

SIZE-DEPENDENT EFFECTS IN ATOMIC CLUSTERS

2020 ◽  
Author(s):  
A. S. Sharipov ◽  
◽  
B. I. Loukhovitski ◽  
Keyword(s):  
Binding Energy ◽  
Physical Properties ◽  
Size Dependence ◽  
Atomic Clusters ◽  
Energy Collision ◽  
Size Dependent

The size-dependence of different physical properties of atomic clusters (by the example of binding energy, collision diameter, and static isotropic polarizability) is discussed.

Size-dependent elastic moduli of platelike nanomaterials

2003 ◽  
Vol 93 (2) ◽  
pp. 1212-1218 ◽  
Author(s):  
C. T. Sun ◽  
Haitao Zhang
Keyword(s):  
Elastic Moduli ◽  
Size Dependent

scholarly journals Large cells activate global protein degradation to maintain cell size homeostasis

2021 ◽  
Author(s):  
Shixuan Liu ◽  
Ceryl Tan ◽  
Chloe Melo-Gavin ◽  
Kevin G. Mark ◽  
Miriam Bracha Ginzberg ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Protein Synthesis ◽  
Protein Degradation ◽  
Cell Size ◽  
Cell Cycle Progression ◽  
Mapk Pathway ◽  
Cellular Growth ◽  
Small Cells ◽  
Animal Cells ◽  
Size Dependent

Proliferating animal cells maintain a stable size distribution over generations despite fluctuations in cell growth and division size. This tight control of cell size involves both cell size checkpoints (e.g., delaying cell cycle progression for small cells) and size-dependent compensation in rates of mass accumulation (e.g., slowdown of cellular growth in large cells). We previously identified that the mammalian cell size checkpoint is mediated by a selective activation of the p38 MAPK pathway in small cells. However, mechanisms underlying the size-dependent compensation of cellular growth remain unknown. In this study, we quantified global rates of protein synthesis and degradation in naturally large and small cells, as well as in conditions that trigger a size-dependent compensation in cellular growth. Rates of protein synthesis increase proportionally with cell size in both perturbed and unperturbed conditions, as well as across cell cycle stages. Additionally, large cells exhibit elevated rates of global protein degradation and increased levels of activated proteasomes. Conditions that trigger a large-size-induced slowdown of cellular growth also promote proteasome-mediated global protein degradation, which initiates only after growth rate compensation occurs. Interestingly, the elevated rates of global protein degradation in large cells were disproportionately higher than the increase in size, suggesting activation of protein degradation pathways. Large cells at the G1/S transition show hyperactivated levels of protein degradation, even higher than similarly sized or larger cells in S or G2, coinciding with the timing of the most stringent size control in animal cells. Together, these findings suggest that large cells maintain cell size homeostasis by activating global protein degradation to induce a compensatory slowdown of growth.

scholarly journals Energetic analysis of succinic acid in water droplets: insight into the size-dependent solubility of atmospheric nanoparticles

2021 ◽  
Author(s):  
Chuchu Chen ◽  
Xiaoxiang Wang ◽  
Kurt Binder ◽  
Mohammad Mehdi Ghahremanpour ◽  
David van der Spoel ◽  
...  
Keyword(s):  
Succinic Acid ◽  
Size Dependence ◽  
Volume Ratio ◽  
Size Dependent ◽  
Bulk Volume ◽  
Energetic Analysis ◽  
Entropic Effect ◽  
Dynamics Simulations ◽  
Enhanced Surface ◽  
Potential Of Mean Forces

Abstract. Size-dependent solubility is prevalent in atmospheric nanoparticles, but a molecular level understanding is still insufficient, especially for organic compounds. Here, we performed molecular dynamics simulations to investigate the size dependence of succinic acid solvation on the scale of ~1–4 nm with the potential of mean forces method. Our analyses reveal that the surface preference of succinic acid is stronger for a droplet than the slab of the same size, and the surface propensity is enhanced due to the curvature effect as the droplet becomes smaller. Energetic analyses show that such surface preference is primarily an enthalpic effect in both systems, while the entropic effect further enhances the surface propensity in droplets. On the other hand, with decreasing droplet size, the solubility of succinic acid in the internal bulk volume may decrease, imposing an opposite effect on the size dependence of solubility as compared with the enhanced surface propensity. Meanwhile, structural analyses, however, show that the surface to internal bulk volume ratio increases drastically, especially when considering the surface in respect to succinic acid, e.g., for droplet with radius of 1 nm, the internal bulk volume would be already close to zero for the succinic acid molecule.

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