Development of a microarray-based method for allergen-specific IgE and IgG4 detection.

Background: sIgE and sIgG4 detection is necessary for more accurate and effective type I hypersensitivity diagnostics and the estimation of disease development. Typically, the analyses of these antibodies are performed separately with the help of various specialized systems. The aim of this study was to develop a microarray-based method for the simultaneous quantitative detection of sIgE and sIgG4 to the most common allergens in a single sample.

Liquid crystal alignment at macroscopically isotropic polymer surfaces: Effect of an isotropic-nematic phase transition.

We study the effect of an isotropic-nematic (I-N) phase transition on the liquid crystal alignment at untreated polymer surfaces. We demonstrate that the pattern at the untreated substrate in the planar cell where the other substrate is uniformly rubbed strongly depends on the temperature gradient across the cell during the I-N phase transition, being macroscopically isotropic if the untreated substrate is cooled faster, but becoming almost homogeneous along the rubbing direction in the opposite temperature gradient. We interpret the observed effect using complementary models of heat transfer and nematic elasticity.

Coupled director and polarization fluctuations in suspensions of ferroelectric nanoparticles in nematic liquid crystals.

In colloidal suspensions of nanosized ferroelectric particles and nematic liquid crystals a large increase in the isotropic-nematic transition temperature has been observed recently. By dynamic light scattering we measured the relaxation rate of the nematic director fluctuations in colloidal systems with BaTiO3 and Sn2P2S6 particles. A substantial increase in the bend-mode relaxation rate, attributed to an increase in the bend elastic constant, is observed.

Orientational coupling amplification in ferroelectric nematic colloids.

We investigated the physical properties of low concentration ferroelectric nematic colloids, using calorimetry, optical methods, infrared spectroscopy, and capacitance studies. The resulting homogeneous colloids possess a significantly amplified nematic orientational coupling. We find that the nematic orientation coupling increases by approximately 10% for particle concentrations of 0.

All-optical switching in a nematic liquid crystal twist cell.

Continuous wave photorefractive-like all-optical switching was demonstrated using a twisted nematic liquid crystal cell composed of the liquid crystal 5CB (4-pentyl-4'-cyanobiphenyl) with polyvinyl alcohol (PVA) aligning layers. The nonlinear optical effect involved is due to optical control of surface charge on the polyvinyl alcohol alignment layer. The cell exhibits strong optical control of the Friedericksz transition by an argon ion laser.