Generation and Propagation of Flexoelectricity-Induced Solitons in Nematic Liquid Crystals.

Solitons in nematic liquid crystals facilitate the rapid transport and sensing in microfluidic systems. Little is known about the elementary conditions needed to create solitons in nematic materials. In this study, we apply a combination of theory, computational simulations, and experiments to examine the formation and propagation of solitary waves, or "solitons", in nematic liquid crystals under the influence of an alternating current (AC) electric field.

Control of liquid crystals combining surface acoustic waves, nematic flows, and microfluidic confinement.

The optical properties of liquid crystals serve as the basis for display, diagnostic, and sensing technologies. Such properties are generally controlled by relying on electric fields. In this work, we investigate the effects of microfluidic flows and acoustic fields on the molecular orientation and the corresponding optical response of nematic liquid crystals.

Minimal Model of Solitons in Nematic Liquid Crystals.

Solitons in liquid crystals have generated considerable interest. Several hypotheses of varying complexity have been advanced to explain how they arise, but consensus has not emerged yet about the underlying forces responsible for their formation or their structure. In this work, we present a minimal model for solitons in achiral nematic liquid crystals, which reveals the key requirements needed to generate them in the absence of added charges.

Jetting and Droplet Formation Driven by Interfacial Electrohydrodynamic Effects Mediated by Solitons in Liquid Crystals.

Solitons are highly confined, propagating waves that arise from nonlinear feedback in natural (e.g., shallow and confined waters) and engineered systems (e.

Programming Solitons in Liquid Crystals Using Surface Chemistry.

AC electric fields cause three-dimensional orientational fluctuations (solitons) to form and rapidly propagate in confined films of liquid crystals (LCs), offering the basis of a new class of active soft matter (e.g., for accelerating mixing and transport processes in microscale chemical systems).

Logic operations with active topological defects.

Logic operations performed by semiconductor-based transistors are the basis of modern computing. There is considerable interest in creating autonomous materials systems endowed with the capability to make decisions. In this work, we introduce the concept of using topological defects in active matter to perform logic operations.

Defect Spirograph: Dynamical Behavior of Defects in Spatially Patterned Active Nematics.

Topological defects in active liquid crystals can be confined by introducing gradients of activity. Here, we examine the dynamical behavior of two defects confined by a sharp gradient of activity that separates an active circular region and a surrounding passive nematic material. Continuum simulations are used to explain how the interplay among energy injection into the system, hydrodynamic interactions, and frictional forces governs the dynamics of topologically required self-propelling +1/2 defects.

Transformation between elastic dipoles, quadrupoles, octupoles, and hexadecapoles driven by surfactant self-assembly in nematic emulsion.

Emulsions comprising isotropic fluid drops within a nematic host are of interest for applications ranging from biodetection to smart windows, which rely on changes of molecular alignment structures around the drops in response to chemical, thermal, electric, and other stimuli. We show that absorption or desorption of trace amounts of common surfactants can drive continuous transformations of elastic multipoles induced by the droplets within the uniformly aligned nematic host. Out-of-equilibrium dynamics of director structures emerge from a controlled self-assembly or desorption of different surfactants at the drop-nematic interfaces, with ensuing forward and reverse transformations between elastic dipoles, quadrupoles, octupoles, and hexadecapoles.

Spatiotemporal control of liquid crystal structure and dynamics through activity patterning.

Active materials are capable of converting free energy into mechanical work to produce autonomous motion, and exhibit striking collective dynamics that biology relies on for essential functions. Controlling those dynamics and transport in synthetic systems has been particularly challenging. Here, we introduce the concept of spatially structured activity as a means of controlling and manipulating transport in active nematic liquid crystals consisting of actin filaments and light-sensitive myosin motors.

Active motion of multiphase oil droplets: emergent dynamics of squirmers with evolving internal structure.

Synthetic soft matter systems, when driven beyond equilibrium by active processes, offer the potential to achieve dynamical states and functions of a complexity found in living matter. Emulsions offer the basis of a simple yet versatile system for identification of the physicochemical principles underlying active soft matter, but how multiple internal phases within emulsion droplets (e.g.

Direct Observation of Liquid Crystal Droplet Configurational Transitions using Optical Tweezers.

Liquid crystals (LCs) are easily influenced by external interactions, particularly at interfaces. When rod-like LC molecules are confined to spherical droplets, they experience a competition between interfacial tension and elastic deformations. The configuration of LCs inside a droplet can be controlled using surfactants that influence the interfacial orientation of the LC molecules in the oil-phase of an oil in water emulsion.

Reticulo-cutaneous fistula due to the ingestion of a long metallic rod in a cow.

A five-year-old cow was referred to the veterinary faculty hospital for treatment of a swelling mass with a cutaneous fistula at the left lower part of the chest wall, between 7th till 9th intercostals space. Abdominal pain in palpation of the mass was observed with no abnormality in clinical symptoms. In surgical exploration, skin incision was carried out on the swelling mass and surprisingly a sinus tract with a sharp metallic rod (26 cm length) that continued to the reticulum lumen was identified.

High seroprevalence of bluetongue virus antibodies in goats in southeast Iran.

Objective: To describe the seroprevalence rate of bluetongue virus (BTV) in goat flocks in southeast of Iran.

Methods: The blood samples were collected randomly from herds of southeast of Iran. A total of 93 sera samples were collected between 2011 and 2012.

High Mortality Rate due to False Gid in a Sheep Herd.

The sheep nasal bot, Oestrus ovis (Diptera: Oestridae), is a cosmopolitan parasite commonly found in sheep and occasionally goats. Rarely a bot will migrate into the sheep brain (false gid). Following the complaint of an animal husbandman about high mortality rate in a sheep herd, the herd was clinically, hematologically, and pathologically examined exactly.

A serological investigation of bluetongue virus in cattle of south-east Iran.

The aim of this study was to describe the seroprevalence rate of bluetongue virus (BTV) in cattle herds in south-east Iran. A total of 188 serum samples were collected from 20 cattle herds (10 animals in each herd) that were randomly selected between 2009 and 2010. A total of 12 samples were eliminated because of inadequacy.

Evaluation of the brain, renal, and hepatic effects of flunixin meglumine, ketoprofen, and phenylbutazone administration in Iranian fat-tailed sheep.

Purpose: The purpose of this study was to evaluate the brain, renal, and hepatic effects of three NSAIDs (flunixin meglumine, ketoprofen, and phenylbutazone) when administered IV to clinically normal Iranian fat-tailed sheep.

Methods: The experiments were conducted on twenty clinically normal adult female sheep. Sheep were randomly assigned to four groups: saline (n = 5), flunixin meglumine (n = 5), ketoprofen (n = 5), and phenylbutazone (n = 5).