Neural plate | EPFL Graph Search

The neural plate is a key developmental structure that serves as the basis for the nervous system. Cranial to the primitive node of the embryonic primitive streak, ectodermal tissue thickens and flattens to become the neural plate. The region anterior to the primitive node can be generally referred to as the neural plate. Cells take on a columnar appearance in the process as they continue to lengthen and narrow. The ends of the neural plate, known as the neural folds, push the ends of the plate up and together, folding into the neural tube, a structure critical to brain and spinal cord development. This process as a whole is termed primary neurulation. Signaling proteins are also important in neural plate development, and aid in differentiating the tissue destined to become the neural plate. Examples of such proteins include bone morphogenetic proteins and cadherins. Expression of these proteins is essential to neural plate folding and subsequent neural tube formation. Generally divided into four, the process of primary neurulation involves the neural plate in the first three steps. The formation and folding of the neural plate is the first step in primary neurulation. This is followed by the refinement and growth of neural plate cells. The third step of primary neurulation does not involve the neural plate per se, but rather the edges of the neural plate, which come together, turning the plate into the start of the neural tube. With the neural plate having folded into a tube, the neural folds come together to complete the fusion of the neural tube. This process is illustrated in the figure to the right, where the neural plate is shown in purple. The lime green marks the edges of the neural plate, which become the neural folds, involved in the folding of the plate to create the neural tube. The figure demonstrates the development of the neural plate into the neural tube, which is where the neural crest cells are derived from as well.

Origami - Folded Plate Structures

Hans Ulrich Buri

This research investigates new methods of designing folded plate structures that can be built with cross-laminated timber panels. Folded plate structures are attractive to both architects and engineers for their structural, spatial, and plastic qualities. Thin surfaces can be stiffened by a series of folds, and thus not only cover space, but also act as load bearing elements. The variation of light and shadow along the folded faces emphasizes the plasticity of space and envelope. Folds not only create structural depth, but also perceptual deepness. Folds give rhythm to space, and variations can be used to express a spatial sequence as well as to modify the structural strength. Because of this we are convinced that a design method which rapidly generates and modifies folded plate structures is of great interest, and can form the basis of a productive collaboration between architects and engineers. In the last fifteen years the timber industry has developed new, large size, timber panels. Composition and dimensions of these panels and the possibility of milling them with Computer Numerical Controlled machines shows great potential for folded plate structures. An interdisciplinary team investigates architectural, structural and mathematical aspects of folded plate structures. The main focus of the architectural portion is the form-finding process which is inspired by Origami, the Japanese art of paper folding. Based on a simple technique, Origami gives birth to an astonishing formal richness and variability. Complex geometries are generated in an economic way and this research aims at transferring these principles to construction with timber panels. In an intuitive approach, we investigate different folding patterns with paper folding. The geometry of selected patterns is analyzed with the aim to generate them in 3D modeling software. We develop a method that generates doubly-corrugated surfaces by two polygonal lines: the corrugation profile and the cross section profile. The corrugation profile defines the characteristics of simply-corrugated surfaces, composed of straight main folds. Simply-corrugated surfaces can be bent by reverse folds. A series of investigations outlines the parameters which influence the geometry of reverse folds. The cross section profile introduces a secondary corrugation. It outlines the general shape of the folded plate geometry and defines the bending angles of the reverse folds. The pattern of folded plate geometries is qualified by the configuration of the two profiles. We establish the conditions which allow control of the pattern type and design of folded plate geometries which respect a given corrugation amplitude. This allows rapid representation of complex folded plate structures in space as well as unfolded. A great variety of forms can be generated. This variability is attractive because it allows the engineer as well as the architect to react on project specific conditions by modifying different parameters of the folded plate structure without distorting its expressive character. Further on the possibilities of offseting the generated surface are investigated. The influence of different parameters on the offset geometry is shown. Finally a series of prototypes investigates the feasibility of folded plate structures generated with the proposed design method.

EPFL2010

Origami - Folded Plate Structures

Hans Ulrich Buri

EPFL2010