The Mechanics of Heterotypic Cell Aggregates: Insights From Computer Simulations

2000 ◽  
Vol 122 (4) ◽  
pp. 402-407 ◽  
Author(s):  
G. Wayne Brodland ◽  
Helen H. Chen
Keyword(s):  
Finite Element ◽  
Pattern Formation ◽  
Interfacial Tension ◽  
Computer Simulations ◽  
Cell Sorting ◽  
Experimental Investigations ◽  
Checkerboard Pattern ◽  
Cell Aggregates ◽  
Tissue Engulfment ◽  
Cell Cell

Finite element–based computer simulations are used to investigate a number of phenomena, including tissue engulfment, cell sorting, and checkerboard-pattern formation, exhibited by heterotypic cell aggregates. The simulations show that these phenomena can be driven by a single equivalent force, namely a surface (or interfacial) tension, that results from cytoskeletal components and cell–cell adhesions. They also reveal that tissue engulfment, cell sorting, and checkerboard-pattern formation involve several discernible mechanical features or stages. With the aid of analytical arguments, we identify the conditions necessary for each of these phenomena. These findings are consistent with previous experimental investigations and computer simulations, but pose significant challenges to current theories of cell sorting and tissue engulfment. [S0148-0731(00)01304-2]

Conditions for Cell Sorting, Mixing and Checkerboard Pattern Formation Determined Using Mechanics and Computer Simulations

2000 ◽  
Author(s):  
G. W. Brodland
Keyword(s):  
Pattern Formation ◽  
Computer Simulations ◽  
Cell Sorting ◽  
Necessary Conditions ◽  
Sufficient Conditions ◽  
Checkerboard Pattern ◽  
Biological Cells

Abstract Sufficient conditions for the sorting of biological cells and necessary conditions for cell mixing and checkerboard pattern formation are derived using principles of mechanics and confirmed by computer simulations.

The Differential Interfacial Tension Hypothesis (DITH): A Comprehensive Theory for the Self-Rearrangement of Embryonic Cells and Tissues

2002 ◽  
Vol 124 (2) ◽  
pp. 188-197 ◽  
Author(s):  
G. Wayne Brodland
Keyword(s):  
Finite Element ◽  
Cell Adhesion ◽  
Interfacial Tension ◽  
Computer Simulations ◽  
Cell Types ◽  
The Self ◽  
Embryonic Cells ◽  
Comprehensive Theory

A comprehensive theory, herein named the Differential Interfacial Tension Hypothesis (DITH), for the self-rearrangement of embryonic cells and tissues is presented. These rearrangements include sorting, mixing and formation of checkerboard patterns in heterotypic aggregates of embryonic cells, and total or partial engulfment, separation and dissociation of tissues. This broadly-based theory accounts for the action of all currently known cytoskeletal components and cell adhesion mechanisms. The theory is used to derive conditions for the cell and tissue rearrangements named above. Finite element-based computer simulations involving two or more cell types confirm these conditions.

A Computer Simulation Approach for Engineering Air-Jet Spun Yarns

1997 ◽  
Vol 67 (3) ◽  
pp. 223-230 ◽  
Author(s):  
Rangaswamy Rajamanickam ◽  
Steven M. Hansen ◽  
Sundaresan Jayaraman
Keyword(s):  
Computer Simulation ◽  
Computer Simulations ◽  
Fiber Length ◽  
Experimental Investigations ◽  
Simulation Approach ◽  
Air Jet ◽  
Fiber Fineness ◽  
Spun Yarns ◽  
Yarn Count ◽  
Wrap Angle

A computer simulation approach for engineering air-jet spun yarns is proposed, and the advantages of computer simulations over experimental investigations and stand-alone mathematical models are discussed. Interactions of the following factors in air-jet spun yarns are analyzed using computer simulations: yarn count and fiber fineness, fiber tenacity and fiber friction, fiber length and fiber friction, and number of wrapper fibers and wrap angle. Based on the results of these simulations, yarn engineering approaches to optimize strength are suggested.

A Model to Explain the Variations of “End-of-Range” Defect Densities with Ion Implantation Parameters

1992 ◽  
Vol 279 ◽  
Author(s):  
L. Laanab ◽  
C. Bergaud ◽  
M. M. Faye ◽  
J. Faure ◽  
A. Martinez ◽  
...  
Keyword(s):  
Ion Implantation ◽  
Computer Simulations ◽  
Point Defects ◽  
Numerical Optimization ◽  
Experimental Investigations ◽  
Shallow Junctions ◽  
Quantitative Explanation ◽  
Defect Densities

ABSTRACTComputer simulations in conjunction with TEM experiments have been used to test the different models usually adopted in the literature to explain the formation of “End Of Range”(EOR) defects which appear after annealing of preamorphized silicon layers. Only one survives careful experimental investigations involving Si+, Ge+, Sn+ amorphization at RT and LNT. The “excess-interstitial” model appears relevant at least for a semi-quantitative explanation of the source of point-defects which after recombination and agglomeration, lead to the formation of these defects. This model may be used for the numerical optimization of conditions for the production of high performances ullra-shallow junctions.

scholarly journals Computer Simulations of Cell Sorting Due to Differential Adhesion

PLoS ONE ◽  
2011 ◽  
Vol 6 (10) ◽  
pp. e24999 ◽  
Author(s):  
Ying Zhang ◽  
Gilberto L. Thomas ◽  
Maciej Swat ◽  
Abbas Shirinifard ◽  
James A. Glazier
Keyword(s):  
Computer Simulations ◽  
Cell Sorting ◽  
Differential Adhesion

A Highly Accurate Beam Finite Element for Curved and Twisted Helicopter Blades

2011 ◽  
Author(s):  
Yan Skladanek ◽  
Paul Cranga ◽  
Guy Ferraris ◽  
Georges Jacquet ◽  
Re´gis Dufour
Keyword(s):  
Finite Element ◽  
Twist Angle ◽  
Experimental Investigations ◽  
Rotating Frame ◽  
Blade Design ◽  
Helicopter Blades ◽  
Performance Improvements ◽  
Blade Optimization ◽  
Model Reliability ◽  
Numerical Tools

Blade optimization is more than ever a crucial activity for helicopter manufacturers, always looking for performance improvements, noise reduction and vibratory comfort increase. Latest studies have led to design new blade concepts including a double swept plan shape, an evolutionary and increased twist angle at the tip and a new layout for internal components like roving spars. Such blades exhibit a highly coupled behavior between torsion, longitudinal and bending motions that should be accurately modeled for predictive numerical tools. In this research a highly accurate beam finite element is formulated in the rotating frame to improve the static deformation calculation under aerodynamic and centrifugal loads and thus enhance dynamic and stability analysis usually performed for a helicopter development. Numerical and experimental investigations are performed to demonstrate the model reliability both for academic beams with extreme shape and for actual blade design.

scholarly journals Numerical Prediction Of The Effect Of Lamination Orientation On Fracture Behaviour Of Wires For Civil Engineering Applications

2014 ◽  
Vol 60 (4) ◽  
pp. 397-408
Author(s):  
K.K. Adewole ◽  
S.J. Bull
Keyword(s):  
Finite Element ◽  
Civil Engineering ◽  
Fracture Behaviour ◽  
Fe Analysis ◽  
Experimental Investigations ◽  
Engineering Applications ◽  
Steel Wires ◽  
Fracture Shape ◽  
Pointed End ◽  
Prediction Approach

AbstractThis paper presents a numerical investigation of the effects of lamination orientation on the fracture behaviour of rectangular steel wires for civil engineering applications using finite element (FE) analysis. The presence of mid-thickness across-the-width lamination changes the cup and cone fracture shape exhibited by the lamination-free wire to a V-shaped fracture with an opening at the bottom/pointed end of the V-shape at the mid-thickness across-the-width lamination location. The presence of mid-width across-the-thickness lamination changes the cup and cone fracture shape of the lamination-free wire without an opening to a cup and cone fracture shape with an opening at the lamination location. The FE fracture behaviour prediction approach adopted in this work provides an understanding of the effects of lamination orientation on the fracture behaviour of wires for civil engineering applications which cannot be understood through experimental investigations because it is impossible to machine laminations in different orientations into wire specimens.

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