Solid Lipid Nanoparticles: A Potential Approach for Dermal Drug Delivery

Solid lipid nanoparticles (SLNs) have attracted increasing attention during recent years. Due to their unique size dependent properties, lipid nanoparticles offer possibilities to develop new therapeutics. The ability to incorporate drugs into nanoparticles offers a new prototype in drug delivery thus realizing the dual goal of both controlled release and site-specific drug delivery. Drug delivery to the skin is widely used for local and systemic delivery and has potential to be improved by application of nanoparticulate formulations. If investigated appropriately, solid lipid nanoparticles may open new opportunities in therapy of complex diseases which is difficult to treat

Studies on high strength defects in nematic liquid crystals?

We recently reported the discovery of stable disclinations of strength ±3/2 and ±2 in mixtures of several nematogenic compounds with a non-mesomorphic compound having plate-like molecules. We describe here further detailed observations on these defects, particularly on pairs of high strength disclinations

Elasticity and orientational order in some cyanobiphenyls: Part IV. Reanalysis of the data

We present revised absolute values of the elastic constants and order parameters of several cyanobiphenyls. The calculations make use of our earlier measurements of Freedericksz threshold fields and refractive indices, and corrected values of normalizing constants, particularly in respect of the anisotropy of magnetic susceptibility. The new values agree well with some recent measurements

On the occurrence of point and ring defects in the nematic-nematic coexistence range of a binary mixture of rod-like and disc-like mesogens

We report some observations on the director configurations in the coexistence range of two nematic phases, NR and ND in a binary mixture of rod-like and disc- like nematogens. The director alignment is continuous across the boundary of the NR and ND phases. Point defects of strength + 1 in NR droplets in an otherwise continuous ND medium are found to be annulled by singular ring disclinations of strength - ½ Further, the NR drops which orient homeotropically at the glass plates have a point defect of strength + 1 only if their size is less than about 7 μm. Larger drops have ring disclinations of strength + ½ instead of + 1 point defects. This changeover can be understood on the basis of simple energy considerations

Experimental determination of the elastic constant k<SUB>13</SUB> of a nematic liquid crystal

The elastic constant k13 is the coefficient of a divergence term in the free energy density and involves the second derivative of the director field. Thus its influence is felt only at the surface of the sample. We have analysed the optical path difference of a hybrid aligned nematic liquid crystal PCH7 taken in a cell which has a weak homeotropic alignment on one glass plate and a strong homogeneous alignment on the other. We use the approximation that solutions in the class of Euler-lagrange equations are valid up to the boundaries and extract both k13 and the anchoring energy at the homeotropically aligned surface. In view of the recent argument by Oldano and Barbero that the k13 term by itself may lead to discontinuities in the director configuration near the surfaces our measurements may be taken to yield an 'effective' value which may have contributions from other terms influencing the director configuration at the surface

Component orientational order parameter in binary mixtures

We have used the IR dichroism technique to measure the component order parameters of two different cyanobiphenyl compounds in two binary mixtures. The measurements clearly show that smectic-like short range order considerably enhances the orientational order in the nematic phase. Further, the temperature variation of the orientational order is also increased by virtue of that of the smectic-like short range order

Anomalous temperature dependence of elastic constants in the nematic phase of binary mixtures made of rodlike and bent-core molecules

We report on two anomalous trends in the temperature dependences of the splay (K11) and bend (K33) elastic constants in the nematic (N) phase of mixtures of compounds with rodlike (R) and bent-core (BC) molecules: As the sample is cooled from the isotropic to N transition point, (i) K33 increases, attains a maximum value and then decreases, and (ii) close to the N to smectic A (SmA) transition point, K11 decreases sharply. At higher temperatures the bow axes of BC molecules are aligned along the director n^, strongly favoring a bend distortion of n^ as the orientational order parameter is increased. Close to the N-SmA transition point the smecticlike short-range order builds up, and the arrow axes of BC molecules are aligned along n^, facilitating a splay distortion of n^. A simple model calculation brings out the anomalous trend in K33

Clinical significance of Kriyakala in Ayurveda

Ayurveda is an ancient bunch of knowledge which aims at maintaining the health of a healthy individual and curing the diseased one. This is brought by equalizing Dosha, Dhatu and Mala. The term Kriyakala refers to the recognition of the stage of a disease's progress, which helps to determine appropriate measure to correct the imbalance in Doshas (biological factors). It is a compound expression, comprised of Kriya and Kala, where Kriya means the choice to treatment (medicine, food and daily-routine) used to improve the disturbance in Doshas, and Kala refers to the stage of progress of a disease. The six stages mentioned by Acharya Sushruta gives an idea regarding the state of the disease in the body and it guides us when to intervene. Early diagnosis of diseases helps to cure the diseases successfully without much discomfort in planning treatment. The primary objective of this study is to describe the importance of Kriyakala in prognosis and diagnosis of the disease. The concept is traced through classical texts. Kriyakala gives us the knowledge of diagnosis, prognosis and the level of intervention and so that to prevent the establishment of a disease