The behavior of particles driven through a narrow constriction is investigated in experiment and simulation. The system of particles adapts to the confining potentials and the interaction energies by a self-consistent arrangement of the particles. It results in the formation of layers throughout the channel and of a density gradient along the channel. The particles accommodate to the density gr...

We consider a system of charged particles interacting with an unscreened Coulomb repulsion in a two-dimensional parabolic confining trap. The static charge on a portion of the particles is twice as large as the charge on the remaining particles. The particles separate into a shell structure with those of greater charge situated farther from the center of the trap. As we vary the ratio of the nu...

Single-domain magnetite crystals have been isolated and characterized from tissue located in a sinus within the dermethmoid bone of the skull of the yellowfin tuna, Thunnus albacares. Their chemical composition, narrow size distribution, and distinctive crystal morphology indicate that these crystals are biochemical precipitates. Experiments on the interaction between particles reveal the organ...

A Yagi-Uda-like optical nanoantenna concept using resonant core-shell plasmonic particles as its “reflectors” and “directors” is studied numerically. Such particles when placed near an optical dipole source in a certain arrangement may exhibit large induced dipole moments, resulting in shaping the far-field radiation pattern, analogous to the far field of classical Yagi-Uda antennas in the micr...

The Balbiani Rings (BR) in the polytene chromosomes of Chironomus salivary glands are intense sites of transcription. The nascent RNPs fold during transcription into 40-50-nm granules, containing in the mature transcript approximately 37-kb RNA. Using a new nucleic acid specific stain, osmium ammine B on Lowicryl sections, in combination with electron energy filtered imaging of sections contain...

Anisotropy of sand is mainly due to the geometrical arrangement of particles that depends on the orientation of applied load respect to the bedding plane. It is geologically due to micro-fabric created by the arrangement of the particles configured during deposition. Most of the models develop using stress/strain invariants are not capable of identifying this kind of anisotropy. This is mainly ...

The granulosa follicle cell of the Graafian follicle of the rabbit ovary differentiates into a lutein cell involved in steroid synthesis. Cytological events which occur within the granulosa cell of the normally stimulated follicle prior to ovulation have been duplicated by the intrafollicular injection of exogenous gonadotrophin. The luteinization of the granulosa cells involves the accumulatio...

The ability of manipulating mesoscopic objects with high precision and flexibility is extremely important for a wide variety of fields from physics, biochemistry, to biomedicine. Particularly, the ability of arranging particles/cells into desired patterns precisely is a challenge for numerous physical and biological applications. Here, we report a strategy of realizing highly flexible trapping,...

Physical fixation by rapid freezing followed by freeze-fracture and deep-etching has provided the means for potentially seeing the three-dimensional arrangement in the native state of particles on mitochondrial inner membranes. We have used these techniques to study the tubular cristae of Paramecium in the hope of determining the arrangement of F1 complexes, their abundance, and location in the...

The precise arrangement of microscopic objects is critical to the development of functional materials and ornately patterned surfaces. Here, we present an acoustics-based method for the rapid arrangement of microscopic particles into organized and programmable architectures, which are periodically spaced within a square assembly chamber. This macroscale device employs two-dimensional bulk acous...