Microscopic magnetic particles dispersed in a solvent-or dipolar colloidal fluids-commonly assemble into chains due to a directional attractive interparticle potential. These chained structures can impart optical anisotropy (i.e., birefringence) to dipolar fluids, [1] and have been demonstrated as effective matrix materials in the rapid separation of DNA using microfluidic electrophoresis. [2] In the special case of magnetorheological (MR) systems, which require external fields to induce dipoles in polarizable colloids, an abrupt microstructural transition from isolated (unpolarized) particles into oriented chains can produce dramatic changes in the viscous behavior. [3] This responsive property makes MR fluids attractive as field-controllable damping fluids in hydraulic valves, shock absorbers, brakes, and so on. [4] Dipolar fluids also display interesting ordering phenomena beyond the 1D case. For instance, nickel-coated glass microspheres were shown to pack onto square, oblique, triangular, and even quasicrystalline lattices with five-fold symmetry in 2D. [5a] Binary particle mixtures assembled into ''flower''-like aggregates and superlattices in a planar configuration. [5b,c] In 3D, dipolar fluids were predicted to form rich mesophases as a function of the dipole moment strength, particle volume fraction, and the relative ''hard'' or ''soft'' nature of the colloidal interactions. [6] Examples include the body-centered-tetragonal (bct) and body-centered-orthorhombic (bco) crystals, along with a broad fluid-bct coexistence phase. Yethiraj and van Blaaderen [7] demonstrated these phases experimentally using a system with tunable long-range repulsive (isotropic) and dipolar (anisotropic) interactions. Such a model system is useful for the exploration of uncommon colloidal structures and for the elucidation of phase phenomena, including the field-induced solid-solid transformations between face-centered-cubic (fcc) and bct crystals.A recent trend in colloid science suggests an emerging theme of applying complex particles as structural motifs for an ever increasing array of synthetic materials. Significant progress in the fabrication of submicrometer-and micrometer-sized colloids in the past few years has yielded particles with various nonspherical shape, [8] ''patchy'' functionality, [8a,9] and anisotropic properties ranging from amphiphilicity [10] and polarizability [11] to magnetic anisotropy. [12] An important consideration in the pursuit of self-assembly strategies using such building blocks is to ensure that interactions are well-controlled. Thus, selectivity in ''bonds'' and weak interactions are often more desirable for equilibrium structures, as this allows systems to evolve toward the target structure in a reversible fashion. With regards to nonspherical colloids in particular, a major challenge remains in the limited ability to control the orientation, localization, and registry of the particles.Here, we report the synthesis and microstructure of peanut-shaped colloids with a permanent transverse ma...

The self‐assembly of polystyrene dimer‐ and spherocylinder‐shaped colloids is achieved via controlled drying on glass and silicon substrates. 3D monoclinic colloidal crystal structures are determined from scanning electron microscopy images of sections prepared using focused ion‐beam (FIB) milling. Full photonic bandgaps between the eighth and ninth bands are found for a systematic range of colloidal dimer shapes explored with respect to the degree of constituent lobe fusion and radius ratio. The pseudogap between bands 2 and 3 for spherocylinder‐based monoclinic crystals is also probed using normal incidence reflection spectroscopy.

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Aims The optimal use of intracardiac echocardiography (ICE) may reduce fluoroscopy time and procedural complications during endocardial ablation of cardiac arrhythmias. Due to limited evidence in this area, we conducted the first systematic literature review and meta‐analysis to evaluate outcomes associated with the use of ICE. Methods and Results Studies reporting the use of ICE during ablation procedures vs without ICE were searched using PubMed/MEDLINE. A meta‐analysis was performed on the 19 studies (2186 patients) meeting inclusion criteria, collectively representing a broad range of arrhythmia mechanisms. Use of ICE was associated with significant reductions in fluoroscopy time (Hedges' g −1.06; 95% confidence interval [CI] −1.81 to −0.32; P < .01), fluoroscopy dose (Hedges' g −1.27; 95% CI −1.91 to −0.62; P < .01), and procedure time (Hedges' g −0.35; 95% CI −0.64 to −0.05; P = .02) vs ablation without ICE. A 6.95 minute reduction in fluoroscopy time and a 15.2 minute reduction in procedure time was observed between the ICE vs non‐ICE groups. These efficiency gains were not associated with any decreased effectiveness or safety. Sensitivity analyses limiting studies to an atrial fibrillation (AF) only population yielded similar results to the main analysis. Conclusion The use of ICE in the ablation of cardiac arrhythmias is associated with significantly lower fluoroscopy time, fluoroscopy dose, and shorter procedure time vs ablation without ICE. These efficiency improvements did not compromise the clinical effectiveness or safety of the procedure.

Nonspherical particles of pear-like and spherocylinder shape were organized into diverse two-dimensional (2D) structures, including the orientationally disordered rotator. Dry films with hexagonal, oblique, and centered rectangular symmetry were obtained by using convective assembly to condense and confine the system in a thin meniscus region. Monte Carlo simulations confirmed the transition from fluid to rotator simply as a function of system density and short-bond-length particle morphology.