The ability to assemble nano- and micro- sized colloidal components into highly ordered configurations is often cited as the basis for developing advanced materials. However, the dynamics of stochastic grain boundary formation and motion have not been quantified, which limits the ability to control and anneal polycrystallinity in colloidal based materials. Here we use optical microscopy, Browni...

The crystalline photoreceptor lattice in the Drosophila eye is a paradigm for pattern formation during development. During eye development, activation of proneural genes at a moving front adds new columns to a regular lattice of R8 photoreceptors. We present a mathematical model of the governing activator-inhibitor system, which indicates that the dynamics of positive induction play a central r...

Magnetospirillum sp. AMB-l is a freshwater magnetic bacterium which synthesizes intracellular particles of magnetite (Fe304). A genomic DNA fragment required for synthesis of magnetic particles, was previously isolated from a non-magnetic transposon Tn5 mutant. We have determined the complete nucleotide sequence of this fragment. The 2975 bp region contains two putative open reading frames (ORF...

Initiation and Growth of Uroliths Urolith formation, dissolution, and prevention involve complex physical processes. Major factors include: 1) supersaturation resulting in crystal formation, 2) effects of inhibitors of crystallization and inhibitors of crystal aggregation and growth, 3) crystalloid complexors, 4) effects of promoters of crystal aggregation and growth, and 5) effects of non-crys...

Adhesion of microcrystals that nucleate in tubular fluid to the apical surface of renal tubular cells could be a critical step in the formation of kidney stones, 12% of which contain uric acid (UA) either alone or admixed with calcium oxalates or calcium phosphates. UA crystals bind rapidly to monolayer cultures of monkey kidney epithelial cells (BSC-1 line), used to model the surface of the ne...