Towards complete photonic band gap in a high refractive index nanoparticle-doped blue phase liquid crystal.

Three-dimensional (3D) photonic crystals with complete photonic band gap (PBG) are fascinating due to the possibility of controlling light in all directions. Realizing such photonic crystals is nontrivial due to symmetry requirements and associated fabrication challenges. Liquid crystalline cubic blue phases (BPs) are soft 3D photonic crystals with an incomplete PBG due to the low refractive index contrast (<0.

Effect of Photonic Band Gap on Photoluminescence in a Dye-Doped Blue Phase Liquid Crystal.

Tunability of fluorescence intensity is an essential parameter for enhancing the versatility of devices like emissive displays and solar cells. Soft photonic crystals, with their tunable photonic band gap (PBG), are highly sought-after systems for such purposes. Here, we report modulation of photoluminescence (PL) intensity in a fluorescent dye-doped blue phase liquid crystal, a 3D soft photonic crystal.

A Study of Outcome of Pediatric Cochlear Implantation in Patients with Cochleovestibular Nerve Deficiency.

Objectives: A cochleovestibular nerve deficiency (CVND) could compromise stimulation of nerve by electrical pulses delivered from a cochlear implant, thereby hindering activity along auditory pathway. The evaluation of children with congenital hearing loss with a high-resolution magnetic resonance imaging is presently the investigative modality of choice to diagnose CVND. The aim of this study was to determine the outcomes in pediatric cochlear implant recipients with a diagnosis of CVND.

Cochlear Implantation in Children with Usher's Syndrome: A South Asian Experience.

Usher's syndrome is an autosomal recessive disorder characterized by dual sensory impairment involving both the ears and eyes. Cochlear implantation paves a way to restore hearing loss in such individuals but poor vision among these patients poses additional challenges for the habilitationists. This study aimed to compare the habilitation outcomes and hearing-related quality of life scores of cochlear implantees having Usher syndrome with age-matched cochlear implantees with no such syndromic association.

Effect of gelation on the Frank elastic constants in a liquid crystalline mixture exhibiting a twist bend nematic phase.

We report studies on the Frank elastic constant behaviour of a liquid crystal gel system exhibiting the twist bend nematic (Ntb) phase. Physical gelation is observed to ease the splay and stabilize the twist deformations in the nematic phase preceding the Ntb. More importantly, the ultra-low bend elastic constant (K33) of the system is enhanced by an order of magnitude on gelation.

Paying for Hemodialysis in Kerala, India: A Description of Household Financial Hardship in the Context of Medical Subsidy.

Introduction: Many low- and middle-income countries are implementing strategies to increase dialysis availability as growing numbers of people reach end-stage renal disease. Despite efforts to subsidize care, the economic sustainability of chronic dialysis in these settings remains uncertain. We evaluated the association of medical subsidy with household financial hardship related to hemodialysis in Kerala, India, a state with high penetrance of procedure-based subsidies for patients on dialysis.

Giant enhancement and facile tuning of photoluminescence in a soft anisotropic magneto-gel.

A soft photoluminescent composite, prepared using a nematic liquid crystal and a fluorescent gelator, exhibits a nearly two orders of magnitude increase in fluorescence on addition of superparamagnetic nanoparticles. The internal magnetic field generated leading to an increase in the population of singlet excitons which affects the radiative efficiency, and enhanced ordering of the LC environment are proposed to be responsible for the large increase seen in fluorescence. Also, the nematic nature of the host liquid crystal medium aids in switching of the fluorescence intensity between its anisotropic limits on application of an external electric field with the switch-off time being faster compared to the field-driven switch-on time.

Electrically Tunable Soft Photonic Gel Formed by Blue Phase Liquid Crystal for Switchable Color-Reflecting Mirror.

We report a robust soft photonic crystal system, fabricated using blue phase (BP) liquid crystal, which can efficiently filter the visible light. The BP gel system is obtained without surface treatment or polymerization, and thus is facile and cost effective to fabricate. Perfect monodomain with vivid color is achieved with a low electric field, which can be further tuned to reflect a second color.

Dynamic Orthogonal Switching of a Thermoresponsive Self-Organized Helical Superstructure.

Controllable manipulation of self-organized dynamic superstructures of functional molecular materials by external stimuli is an enabling enterprise. Herein, we have developed a thermally driven, self-organized helical superstructure, i.e.

Effect of Atomic-Scale Differences on the Self-Assembly of Thiophene-based Polycatenars in Liquid Crystalline and Organogel States.

Two series of polycatenars are reported that contain a central thiophene moiety connected to two substituted oxadiazole or thiadiazole units. The number, position, and length of the peripheral chains connected to these molecules were varied. The oxadiazole-based polycatenars exhibited columnar phases with rectangular and hexagonal or oblique symmetry, whereas the thiadiazole-based polycatenars exhibited columnar phases with rectangular and/or hexagonal symmetry.

Optically Biaxial, Re-entrant and Frustrated Mesophases in Chiral, Non-symmetric Liquid Crystal Dimers and Binary Mixtures.

Sixteen optically active, non-symmetric dimers, in which cyanobiphenyl and salicylaldimine mesogens are interlinked by a flexible spacer, were synthesized and characterized. While the terminal chiral tail, in the form of either (R)-2-octyloxy or (S)-2-octyloxy chain attached to salicylaldimine core, was held constant, the number of methylene units in the spacer was varied from 3 to 10 affording eight pairs of (R & S) enantiomers. They were probed for their thermal properties with the aid of orthoscopy, conoscopy, differential scanning calorimetry and X-ray powder diffraction.

Diminished Splay Stiffening in Weak Gels of Calamitic-Bent-Core Nematic Composites.

Composites of calamitic and bent-core nematic molecules exhibiting a nematic to nematic-gel transformation have been investigated using thermal, electrical, X-ray, and mechanical probes. The studies focusing on the Frank elastic behavior show a surprising result that the thermal behavior of the threshold voltage and the dependent splay elastic constant (K11) are remarkably different in temperature regions identified as weak and strong gels. In the former gel, the parameters exhibit values significantly smaller than the higher-temperature fluid nematic, effectively canceling out the underlying thermal variation due to the order parameter.

Phosphaturic mesenchymal tumor of the brain without tumor-induced osteomalacia in an 8-year-old girl: case report.

Phosphaturic mesenchymal tumor (mixed connective tissue variant) (PMT-MCT) are tumors that may cause tumor-induced osteomalacia and rarely appear intracranially. The authors describe the case of an 8-year-old girl who was found to have PMT-MCT with involvement of the cerebellar hemisphere and a small tumor pedicle breaching the dura mater and involving the skull. This was removed surgically in gross-total fashion without further complication.

Influence of polarization-tilt coupling on the ferroelectric properties of smectic gels.

We have studied composites of a ferroelectric liquid crystal mixture with a simple organic gelating agent, employing structural, thermal, electrical and mechanical probes, investigating the influence of the coupling between the polarization and the tilt angle on the ferroelectric properties of smectic gels. The calorimetric data, presenting clear signatures of the gelation occurring in the smectic A (SmA) phase or the isotropic phase, depending on the concentration of the gelator, help in constructing a rich diagram in the temperature-gelator concentration phase space. The atomic force microscopy imaging brings out the interesting feature of the transfer of chirality from the ferroelectric liquid crystal (FLC) to the gel strands, as exemplified by the creation of nanorope structures which have attracted much attention in recent times.

Anchoring transition induced by gelation in a liquid crystal system.

We report a novel type of anchoring transition (ANT) in a liquid crystal driven by the physical gelation of the system. The ANT manifests as anomaly in the thermal behaviour of the dielectric permittivity. Data from X-ray studies suggest that ANT is caused by the ability of the gel fibres to compete with the substrate-driven orientation conditions.

Soft glass rheology in liquid crystalline gels formed by a monodisperse dipeptide.

Thermal and extensive rheological characterization of a nematic liquid crystal gelated with a novel monodisperse dipeptide, also a liquid crystal, has been carried out. For certain concentrations, the calorimetric scans display a two-peak profile across the chiral nematic-isotropic (N*-I) transition, a feature reminiscent of the random-dilution to random-field crossover observed in liquid crystal gels formed with aerosil particles. All samples show shear thinning behavior without a Newtonian plateau region at lower shear rates.

Intraoperative touch imprint and frozen section analysis of sentinel lymph nodes after neoadjuvant chemotherapy for breast cancer.

Objective: To evaluate the accuracy of touch imprint and frozen section analysis of sentinel nodes after neoadjuvant chemotherapy.

Summary Background Data: Intraoperative evaluation of the sentinel node can determine the need for axillary dissection at the time of initial operation and therefore spare the patient a second operation. Little data, however, exists on the accuracy of intraoperative evaluation of sentinel nodes after neoadjuvant chemotherapy.

Electric-field-dictated phase diagram and accelerated dynamics of a reentrant nematic liquid crystal under photostimulation.

In a system consisting of photoactive molecules that exhibit light-driven isomerization transformations, actinic light can diminish or enhance ordering to the extent that transitions from the equilibrium to a more disordered phase can be brought about isothermally. This feature enables light to be used as a thermodynamiclike parameter to investigate phase behavior and adds another dimension to the studies owing to the nonequilibrium character of the isothermal transitions. We have carried out experiments which exploit the combination of two recent findings, viz.

Fast responding robust nematic liquid crystalline gels formed by a monodisperse dipeptide: electro-optic and rheological studies.

Realization of mechanically robust electrically fast responding liquid crystal devices with low operating voltage is one of the current research interests. Here we report a gel system comprising a commercially available nematic liquid crystal material and a new monodisperse dipeptide liquid crystalline organogelator that results in these properties. The gels exhibit nearly 2 orders of magnitude faster switching response than the pure nematic liquid crystal while having 3 orders of magnitude higher zero shear rate viscosity, and with the attractive feature that the switching threshold voltage is hardly altered.

A new Mycobacterium species causing diffuse lepromatous leprosy.

Mycobacterium leprae causes leprosy. M leprae strains collected worldwide have been genetically clonal, which poorly explains the varying severity and clinical features of the disease. We discovered a new Mycobacterium species from 2 patients who died of diffuse lepromatous leprosy (DLL).

Diffuse large B-cell lymphoma presenting as multiple lymphomatous polyposis of the gastrointestinal tract.

Primary gastrointestinal (GI) lymphomas constitute 5%-10% of all gastrointestinal tumors. Involvement of the entire GI tract as multiple polypoid lesions is very rare. Multiple lymphomatous polyposis is a distinctive and rare type of malignant GI lymphoma.

Evidence of wormlike micellar behavior in chromonic liquid crystals: rheological, X-ray, and dielectric studies.

We report rheological, X-ray, and dielectric investigations on a chromonic liquid-crystalline system formed by aqueous solutions of a food coloring agent, Sunset Yellow, in the absence and upon addition of salt. The salt-concentration dependence of the steady-state viscosity at low shear rates has a non-monotonic variation and is qualitatively similar to the behavior seen in wormlike micellar systems, a surprising result since chromonic systems are expected to be non-micellar in character. More interestingly, for a particular low concentration of the salt (20 mM), the viscosity increases by 3 orders of magnitude in comparison with that of the pure chromonic material.