Scattering and absorption properties of multiply coated magnetic nanoparticles.

The optical properties of a material are characterized by its electric and magnetic susceptibilities. Finding analytical expressions for those quantities for a nanoparticle of arbitrary shape is generally a formidable task. A great deal of insight in to the basic phenomena can be obtained by studying analytically solvable cases, for nanoparticles of ellipsoidal and spherical shapes. We present here our study on the scattering and absorptive properties of multiply coated magnetic spherical and elliptical nanoparticles as functions of frequency of an incident electromagnetic radiation. We will present our results based on the analytical expressions for the dielectric and magnetic susceptibilities derived for such multiply coated nanoparticles. To our knowledge, the latter results are new. We will also present our results based on Maxwell-Garnett theory for a material having uniform distribution of mono dispersed multiply coated nanoparticles.

Shape-dependent force between magnetic nanoparticles in a colloidal ferro-fluid.

In the presence of applied magnetic fields, magnetic nanoparticles suspended in a colloidal ferrofluid align themselves in chains if the inter-particle force due to induced dipolar interactions within the chain dominates over the thermal randomization. The variation of this chain force with the interparticle separation and particle volume has been studied in the past for the special case of spherical particles. In the present paper the dependence of the chain-force on the shape of the suspended nanoparticles of prolate spheroidal type has been investigated. Starting with the case of a sphere (eccentricity e = 0), the shape is evolved by varying the eccentricity of the spheroid up to the limiting case of a nano-rod (eccentricity e = 1) while keeping the particle volume and the inter-particle separation fixed. For the first time in our knowledge, the expressions for the bulk susceptibility and hence the induced magnetization of ellipsoidal nanoparticles have been derived and used for the present problem. The variation of chain-force with the inter-particle separation for a fixed shape is also presented.

Attitudes of patients to alternative medicine for cancer treatment.

Awareness of attitudes to different types of medicine is very important for estabishment of cancer prevention programs. Alternative medicine has become an important feature of oncology regardless of geographic region, and in India, the majority of cancer patients present at late advance stage of disease when curative treatment cannot be initiated. Given the lack of facilities it is no surprise that many Indian cancer patients try various complementary and alternative medicines, depsite the fact that little is known about their therapeutic efficacy and toxicity. A study was conducted in 300 biopsy proven cancer patients undergoing alternative cancer therapy with Psorinum in Kolkata. The main aim of the study was to analyze the patients'/caregivers narratives regarding the therapy they have been trying. One hundred and ninety five patients (65%) have consulted their oncologists before trying this therapy. About 18.5% of the patients expressed satisfaction with the therapy due to the holistic nature and team approach employed for patient management. The cost of the therapy was within the reach of many cancer patients belonging to the underprivileged segment of the society, contributing to its immense popularity in Kolkata. Whether this can be translated into a willingness to use similar natural compounds for cancer prevention and treatment purposes now needs to be analysed.