Molecular self-assembly, the formation of large structures by small pieces of matter sticking together according to simple local interactions, is a ubiquitous phenomenon. A challenging engineering goal is to design a few molecules so that large numbers of them can self-assemble into desired complicated target objects. Indeed, we would like to understand the ultimate capabilities and limitations...

Our objective was to grade, by computer-assisted quantitative image tile analysis, the intraepithelial neoplasia (also called dysplasia) that develops in esophagi of rats given N-nitrosomethybenzylamine (NMBA) for 5 weeks. To perform image tile analysis, the computer divides the video image of the neoplastic epithelium into a row of contiguous small rectangular images, or "tiles," 84 x 292 micr...

Experimental demonstration of the Turing universal tile based algorithmic DNA self-assembly has been limited by significant assembly errors. An important class of errors, called co-ordinated growth errors, occur when an incorrect tile binds to a growing assembly even when some of its pads are mismatched with its neighbors. Activatable DNA tiles, introduced originally by [12], employ a protectio...

Welding is a major industrial process used for joining metals. Occupational exposure to welding fumes is a serious occupational health problem all over the world. The degree of risk to welder's health from fumes depends on composition, concentration, and the length of exposure. The aim of this study was to investigate workers' welding fume exposure levels in some industries in Jeddah, Saudi Ara...

The Virtual Factory is a job shop scheduling tool that was developed at NC State. It has been found to provide nearoptimal solutions to industrial-sized problems in seconds. Recently, the Virtual Factory was expanded to include interfactory transportation operations which enabled the detailed scheduling of entire multi-factory manufacturing supply chains. Separately, a rolling horizon procedure...

We have designed and experimentally demonstrated the self-assembly of an addressable DNA lattice (i.e., a unique tile for each position in the lattice) using a two-step tile annealing procedure. Our method can be applied to a variety of systems including algorithmic tiling systems to expand the basic tile set.

We consider the disklikeness of the planar self-affine tile T generated by an integral expanding matrix A and a consecutive collinear digit set D = {0, v, 2v, · · · , (|q|−1)v} ⊂ Z2. Let f(x) = x2+px+q be the characteristic polynomial of A. We show that the tile T is disklike if and only if 2|p| ≤ |q+2|. Moreover, T is a hexagonal tile for all the cases except when p = 0, in which case T is a s...

The Pattern self-Assembly Tile set Synthesis (PATS) problem, which arises in the theory of structured DNA self-assembly, is to determine a set of coloured tiles that, starting from a bordering seed structure, self-assembles to a given rectangular colour pattern. The task of finding minimum-size tile sets is known to be NP-hard. We explore several complete and incomplete search techniques for fi...