Tying knots and linking microscopic loops of polymers, macromolecules, or defect lines in complex materials is a challenging task for material scientists. We demonstrate the knotting of microscopic topological defect lines in chiral nematic liquid-crystal colloids into knots and links of arbitrary complexity by using laser tweezers as a micromanipulation tool. All knots and links with up to six...

We have recently developed a new type of porous silicon we name as porous silicon colloids. They consist of almost perfect spherical silicon nanoparticles with a very smooth surface, able to scatter (and also trap) light very efficiently in a large-span frequency range. Porous silicon colloids have unique properties because of the following: (a) they behave as optical microcavities with a high ...

Introduction In the past year there has been an escalation of the age-old crystalloid–colloid debate as a result of the publication of several systematic reviews assessing the effect of various colloids versus various crystalloids on mortality. In 1998, an excess mortality of 4% for the colloid resuscitated patients was claimed for various colloids versus various crystalloids in various clinica...

Spherical Janus colloids, particles with different surface properties on their two hemispheres, are generally heterogeneous in permittivity. This dielectric heterogeneity may affect their behavior in electrolytes and external electric fields, but is typically not taken into account in computational studies. We apply the iterative dielectric solver developed by Barros and Luijten [Phys. Rev. Let...

A new nanosize colloid detection method comprised of flow-field flow fractionation (FFFF) with laser-induced breakdown detection (LIBD) is presented, which is capable of characterizing the colloid size distribution as well as determining the number density of each size fraction in very low concentrations. The method facilitates the detection of aquatic colloids particularly in the lower range o...

[1] We report results on the effects of porewater pH and transients in porewater flow on the deposition and mobilization of colloid-sized clay particles within unsaturated sand columns. The deposition rates of illite under steady-flow conditions were essentially independent of pH, while the deposition rates of kaolinite nearly doubled as the pH decreased from 7.4 to 4.6. Mobilization of kaolini...

This study reports the feasibility of citratereduced colloidal silver surface-enhanced Raman scattering (SERS) for differentiating three important food borne pathogens, E. coli, Listeria, and Salmonella. FT-Raman and SERS spectra of both silver colloids and colloidK3PO4 mixtures were collected and analyzed to evaluate the reproducibility and stability of silver colloids fabricated in a batch-pr...

Colloidal systems exhibit intriguing assembly phenomena with impact in a wide variety of technological fields. The use of magnetically responsive colloids allows one to exploit interactions with an anisotropic dipolar nature. Here, we reveal magnetic interfacial rotaphoresis - a magnetically-induced rotational excitation that imposes a translational motion on colloids by a strong interaction wi...

We performed passive and active microrheology using probe particles in a bath of well-characterized, model hard-sphere colloids in the fluid state over the whole range of volume fractions below the glass transition. The probe and bath particles have nearly the same size. Passive tracking of probe particles yields short-time self-diffusion coefficients. Comparison with literature data demonstrat...

The transport properties of colloids in anisotropic media constitute a general problem of fundamental interest in experimental sciences, with a broad range of technological applications. This work investigates the transport of soft spherical colloids in binary mixtures with rod-like particles by means of Monte Carlo and Brownian Dynamics simulations. Layered phases are considered, that range fr...