background: a comprehensive database, comprising geometry and properties of human teeth, is needed for dentistry education and dental research. the aim of this study was to create a three-dimensional model of human teeth to improve the dental e-learning and dental research.   methods: in this study, a cross-section picture of the three-dimensional model of the teeth was used. ct-scan images wer...

introduction: mandibular first molar is the most important tooth with complicated morphology. in finite element (fe) studies, investigators usually prefer to model anterior teeth with a simple and single straight root; it makes the results deviate from the actual case. the most complicated and time-consuming step in fe studies is modeling of the desired tooth, thus this study was performed to e...

Common three-dimensional (3D) modeling software mainly uses sequence modeling method based on feature tree structure. This kind of parametric modeling is achieved by using dimensional constraints. However, re-editing of any historical features will cause regeneration of the subsequent features, thus resulting in substantial waste of computer resources and time. Compared with sequence modeling t...

Abbreviations 1D D one-dimensional; 1D structure D one-dimensional (e.g., sequence or string of secondary structure); 2D D two-dimensional; 2D structure D two-dimensional (e.g., interresidue distances); 3D D three-dimensional; 3D structure D three-dimensional (coordinates of protein structure); PDB D Protein Data Bank of experimentally determined 3D structures of proteins; SWISS-PROT D database...

conclusions our underlying hypothesis is that recapitulating the three-dimensional early embryonic structure, in order to reproduce better in vitro the three-dimensional morphogenetic-like re-arrangements, would improve cells differentiation, when in vivo transplanted; moreover, it could be used as a simplified cancer disease model and reliable drug evaluation method as well. results the proces...

the purpose of this study is to correct the static shift of magnetotelluric (mt) data in one of the oil fields located in southwest of iran using time domain electromagnetic (tem or tdem) data. acquisition of the mt data has been made in the same area as the tem data was acquired at the frequency range of 0.0005-320 hertz. . a major problem in the mt method that occurs due to distribution of su...

Recent researches on Three-dimensional Geographic Information System (3D GIS) modeling technology were reviewed. The concept of 3D GIS modeling and its application in various fields were introduced. Essential techniques to realize 3D visualization were studied. A typical 3D GIS modeling usually contains the description and the transmission of GIS spatial data structure. GIS spatial data models ...

The present work investigates the effect of the elliptical three-dimensional (3D) cracks on a pipe with thickness transition, considering internal pressure. Level sets were defined using the extended finite element method (XFEM), the stress intensity factors (SIFs) of 3D cracks were investigated and compared between straight pipes and pipes with thickness transition. The results show that the X...