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Shape Deformation (shape + deformation)

Distribution by Scientific Domains

Polymers and Materials Science	57%

Selected Abstracts

A Discrete, Space Variation Model for Studying the Kinetics of Shape Deformation of Vesicles Coupled with Phase Separation

MACROMOLECULAR THEORY AND SIMULATIONS, Issue 5 2006
Jianfeng Li
Abstract Summary: The evolution dynamics of phase separation, coupled with shape deformation of vesicles is described by using dissipative dynamic equations, specifically the time-dependent Ginzburg-Landau (TDGL) equations. In order to improve the numerical stability and thus to efficiently deal with a large deformation of vesicles, a new algorithm, namely the discrete space variation model (DSVM) has been developed for the first time. The algorithm is based on the variation of the discretized free-energy functional, which is constructed in discrete membrane space, in contrast to the commonly used continuous free-energy functional. For the sake of numerical tractability, only the cylindrical vesicles (2D), with two components, are taken into consideration to illustrate the efficiency and validity of new algorithm. The simulation results, based on the DSVM algorithm have been compared with those from both linear analysis and strong segregation theory using the continuous space free-energy functional. It is found that the DSVM algorithm can correctly describe the coupling between the lateral phase-separation on the vesicle membrane and the vesicle shape deformation, both for early and late stages. A flower-like vesicle obtained by DSVM simulation. [source]

Energy-Based Image Deformation

COMPUTER GRAPHICS FORUM, Issue 5 2009
Z. Karni
Abstract We present a general approach to shape deformation based on energy minimization, and applications of this approach to the problems of image resizing and 2D shape deformation. Our deformation energy generalizes that found in the prior art, while still admitting an efficient algorithm for its optimization. The key advantage of our energy function is the flexibility with which the set of "legal transformations" may be expressed; these transformations are the ones which are not considered to be distorting. This flexibility allows us to pose the problems of image resizing and 2D shape deformation in a natural way and generate minimally distorted results. It also allows us to strongly reduce undesirable foldovers or self-intersections. Results of both algorithms demonstrate the effectiveness of our approach. [source]

Sweep-based Freeform Deformations

COMPUTER GRAPHICS FORUM, Issue 3 2006
Seung-Hyun Yoon
We propose a sweep-based approach to the freeform deformation of three-dimensional objects. Instead of using a volume enclosing the whole object, we approximate only its deformable parts using sweep surfaces. The vertices on the object boundary are bound to the sweep surfaces and follow their deformation. Several sweep surfaces can be organized into a hierarchy so that they interact with each other in a controlled manner. Thus we can support intuitively plausible shape deformation of objects of arbitrary topology with multiple control handles. A sweep-based approach also provides important advantages such as volume preservation. We demonstrate the effectiveness of our technique in several examples. Categories and Subject Descriptors (according to ACM CCS): I.3.5 [Computational Geometry and Object Modeling]: Curve, surface, solid, and object representations [source]

A Discrete, Space Variation Model for Studying the Kinetics of Shape Deformation of Vesicles Coupled with Phase Separation

Characteristics, head shape measurements and developmental delay in 287 consecutive infants attending a plagiocephaly clinic

ACTA PAEDIATRICA, Issue 9 2009
BL Hutchison
Abstract Aim:, To describe the characteristics, developmental status and severity of head shape deformation in infants presenting to a plagiocephaly clinic. Methods:, Head shape was measured and neck function assessed in 287 consecutive infants presenting to a plagiocephaly outpatient clinic. Information was obtained on demographic and obstetric factors, plagiocephaly history and current positioning strategies. Development was assessed by the Ages and Stages Questionnaire (ASQ). Results:, After clinical examination, craniosynostosis was suspected in seven infants (2%) and a skull computed tomography (CT) scan was performed; five showed suture abnormalities. Fifty-eight percent of cases had a history of limitation of neck function; this was more likely in plagiocephalic infants than brachycephalic infants. Males, firstborn infants, instrument-delivered infants, supine sleep position and right-sided flattening were predominant. One or more delays on the ASQ were seen in 36% of infants. Conclusion: Physical examination of infants with head shape deformities is essential in order to rule out craniosynostosis. Infants with deformational plagiocephaly frequently have neck muscle dysfunction. We postulate that the higher than expected number of developmental delays may be related to the effects of supine sleep position, low or variable tone, lower activity levels, male gender and neck muscle dysfunction. [source]

Microstructured Surfaces Cause Severe but Non-Detrimental Deformation of the Cell Nucleus

ADVANCED MATERIALS, Issue 35 2009
Patricia M. Davidson
Surface features on the length scale of organelles allow their manipulation. Here, we present observations of an unexpected deformation of nuclei within cells growing on surfaces with micrometer-sized pillars. Our results demonstrate that a microstructured surface can induce strong shape deformations in cells, without harmful consequences, and strongly suggest that these are limited to cancerous cells. [source]