Silylated Carbon Nanofiber/Polydimethylsiloxane Based Printable Electrorheological and Sensor Inks for Flexible Electronics.

Electrorheological fluids (ERF) have garnered significant attention for their potential to provide actuation on demand. Similarly, developing stimuli-responsive printable inks for flexible electronics is also gaining antecedence. However, developing a material that demonstrates both functionalities is far and few.

Pure elongation flow of an electrorheological fluid: insights on wall slip from electrorheology.

In this work we study the pure elongation flow behavior of an electrorheological (ER) fluid as a model soft-jammed system, wherein the extent of jamming is controlled by an externally applied electric-field. More specifically, a pure elongation flow has been achieved by facilitating significant slip at the contact between the material and rheometer-plate while pulling it with constant pulling velocity under a constant external electric-field. The normal force exerted by the top plate on the material was measured as a function of gap during the flow for various combinations of electric-field strength and pulling velocity.

Thermoresponsive keratin-methylcellulose self-healing injectable hydrogel accelerating full-thickness wound healing by promoting rapid epithelialization.

Chronic wounds suffer from impaired healing due to microbial attack and poor vascular growth. Thermoresponsive hydrogels gained attention in wound dressing owing to their gelation at physiological temperature enabling them to take the shape of asymmetric wounds. The present study delineates the development of thermoresponsive hydrogel (MCK), from hair-derived keratin (K) and methylcellulose (MC) in the presence of sodium sulfate.

Bioactive self-assembling silk fibroin-sericin films for skin tissue engineering.

The quest for an ideal wound dressing material has been a strong motivation for researchers to explore novel biomaterials for this purpose. Such explorations have led to the extensive use of silk fibroin (SF) as a suitable polymer for several applications over the years. Unfortunately, another major silk protein-sericin has not received its due attention yet in spite of having favorable biological properties.

Prediction of viscoelastic properties of peanut-based 3D printable food ink.

Viscoelastic properties of 3D printable peanut-based food ink were investigated using frequency sweep and relaxation test. The incorporation of xanthan gum (XG) improved the shear thinning behavior (n value ranging from 0.139 to 0.

Printable Carbon Nanotube-Liquid Elastomer-Based Multifunctional Adhesive Sensors for Monitoring Physiological Parameters.

Developing a printed elastomeric wearable sensor with good conformity and proper adhesion to skin, coupled with the capability of monitoring various physiological parameters, is very crucial for the development of point-of-care sensing devices with high precision and sensitivity. While there have been previous reports on the fabrication of elastomeric multifunctional sensors, research on the printable elastomeric multifunctional adhesive sensor is not very well explored. Herein, we report the development of a stencil printable multifunctional adhesive sensor fabricated in a solvent-free condition, which demonstrated the capability of having good contact with skin and its ability to function as a temperature and strain sensor.

Microfluidic thin film pressure balance for the study of complex thin films.

Investigations of free-standing liquid films enjoy an increasing popularity due to their relevance for many fundamental and applied scientific problems. They constitute soap bubbles and foams, serve as membranes for gas transport or as model membranes in biophysics. More generally, they provide a convenient tool for the investigation of numerous fundamental questions related to interface- and confinement-driven effects in soft matter science.

Signatures of Overaging in an Aqueous Dispersion of Carbopol.

In this work, we study the effect of the deformation field on the physical aging behavior of an aqueous Carbopol dispersion. It is composed of soft swollen particles of gel that get deformed and acquire a polygonal shape, with flat interfaces rendering the dispersion a soft solid-like consistency as filled volume fraction approaches unity. It has been proposed that owing to release of stored elastic energy in the deformed particles, Carbopol dispersion undergoes microstructural evolution that is reminiscent of physical aging in soft glassy materials.

Biomimetic silk fibroin and xanthan gum blended hydrogels for connective tissue regeneration.

Combination of naturally occurring materials instead of chemically synthesized products has always been an attractive proposition in the field of tissue engineering. In this study, silk fibroin (SF) and xanthan gum(XG) were physically crosslinked to form biocompatible hydrogels. SF/XG hydrogels were prepared using ultrasonication, which induces β-sheets from random coils in SF solution and allows entrapment of heated XG chains homogeneously in the SF network.

Tailorable hydrogel of gelatin with silk fibroin and its activation/crosslinking for enhanced proliferation of fibroblast cells.

Gelatin based hydrogel (Gel) possess remarkable cytocompatibility profile rendering it appropriate for tissue engineering applications. Herein, the questionable mechanical property of Gel was tuned by tailoring with different loading concentrations of silk fibroin (SF). The as tailored matrix was reconnoitred for its physico-mechanical, chemical and biological properties in order to investigate the effect of SF loading.

Three-dimensional yielding in anisotropic materials: validation of Hill's criterion.

Yielding transition in isotropic soft materials under the superposition of orthogonal deformation fields is known to follow von Mises' criterion. However, in anisotropic soft materials, von Mises' criterion fails owing to the preferred directions associated with the system. In this work we study a model anisotropic yield stress system: electrorheological (ER) fluids which show structural formation in the direction of an electric field.

Passive microrheology in the effective time domain: analyzing time dependent colloidal dispersions.

We studied the aging dynamics of an aqueous suspension of LAPONITE®, a model time dependent soft glassy material, using a passive microrheology technique. This system is known to undergo physical aging during which its microstructure evolves progressively to explore lower free energy states. Optical microscopy is used to monitor the motion of micron-sized tracer probes embedded in a sample kept between two glass plates.

Analyzing aging under oscillatory strain field through the soft glassy rheology model.

In this work, we solve the Soft Glassy Rheology (SGR) model under application of oscillatory deformation field with varying magnitudes of strain as well as frequency for different noise temperatures. In the glassy domain, the SGR model undergoes time evolution of elastic modulus. Increase in strain magnitude beyond the linear regime is observed to enhance the rate of aging as manifested by a faster evolution of elastic modulus with increase in strain amplitude due to overaging.

Linear viscoelasticity of soft glassy materials.

Owing to lack of time translational invariance, aging soft glassy materials do not obey fundamental principles of linear viscoelasticity. We show that by transforming the linear viscoelastic framework from a real time domain into an effective time domain, wherein the material clock is readjusted to account for evolution of relaxation time, the soft glassy materials obey effective time translational invariance. Consequently, we demonstrate successful validation of principles of linear viscoelasticity (the Boltzmann superposition principle and a convolution relation for creep compliance and stress relaxation modulus) for different types of soft glassy materials in the effective time domain.

Tailoring relaxation time spectrum in soft glassy materials.

Physical properties of out of equilibrium soft materials depend on time as well as deformation history. In this work we propose to transform this major shortcoming into gain by applying controlled deformation field to tailor the rheological properties. We take advantage of the fact that deformation field of a certain magnitude can prevent particles in an aging soft glassy material from occupying energy wells up to a certain depth, thereby populating only the deeper wells.

Extra vestibular schwannoma: a two year experience.

We present series of head, neck extracranial non-vestibular schwannomas treated during 2-year period. All patients with head and neck schwannomas treated at our department from April 2007 to July 2009 were reviewed. There was female predominance (72%).

Primary hyperparathyroidism: retrospective 10-year study of 32 cases.

Background: Parathyroid glands are endocrine glands that regulate calcium metabolism. Usually four in number, they lie mostly on the posterior aspect of thyroid glands. Primary hyper-parathyroidism (PHPT) refers to a condition wherein they secrete an excess of parathyroid hormone leading to signs and symptoms of hypercalcemia.

Microsatellite instability and its correlation with clinicopathological features in a series of thyroid tumors prevalent in iodine deficient areas.

Thyroid tumors display diverse spectrum of histopathological groups with geographic variation in its prevalence. Influence of iodine deficiency (a major causative factor) in its etiology, prevalence, or aggressiveness is debatable which reflects the existence of various genetic events in pathogenesis. The present study was undertaken to study the role of Microsatellite instability (MSI) or LOH (loss of heterozygosity), an indicator of defective mismatch repair system as a genetic change and to explore it as a prognostic marker in thyroid tumors.

Management of enterocutaneous fistulas.

Despite advances in antimicrobial chemotherapy, nutritional support, and perioperative critical care, the development of an enterocutaneous fistula continues to represent a major therapeutic challenge, with appreciable morbidity and mortality. Specific problems that must be addressed for the successful management of patients with enterocutaneous fistulas are the control of sepsis, maintenance of adequate fluid and electrolyte balance, provision of adequate and complication-free nutritional support, and skin-stoma care. In addition, many patients with postoperative intestinal fistulation suffer from significant psychological morbidity, which must be addressed during often prolonged periods of rehabilitation.