Polystyrene-block-poly(ethylene oxide) copolymers as templates for stacked, spherical large-mesopore silica coatings: dependence of silica pore size on the PS/PEO ratio

Large-mesopore silica films with a narrow pore size distribution and high porosity have been obtained by a sol-gel reaction of a silicon oxide precursor (TEOS) and using polystyrene-block-poly(ethylene oxide) (PS-b-PEO) copolymers as templates in an acidic environment. PS-b-PEO copolymers with different molecular weight and composition have been studied in order to assess the effects of the block length on the pore size of the templated silica films. The changes in the morphology of the porous systems have been investigated by transmission electron microscopy and a systematic analysis has been carried out, evidencing the dependence between the hydrophilic/hydrophobic ratio of the two polymer blocks and the size of the final silica pores. The obtained results prove that by tuning the PS/PEO ratio, the pore size of the templated silica films can be easily and finely predicted

Poly(NIPAM-co-MPS)-grafted multimodal porous silica nanoparticles as reverse thermoresponsive drug delivery system

Hybrid drug delivery systems (DDS) have been prepared by grafting poly(NIPAM-co-MPS) chains on multimodal porous silica nanoparticles having an inner mesoporous structure and an outer thin layer of micropores. The hybrid thermoresponsive DDS were fully characterized and loaded with a model drug. The in vitro drug release tests are carried out at below and above the lower critical solution temperature (LCST) of the copolymer. The results have revealed that due to the presence of small diameter (~1.3 nm) micropores at the periphery of the particles, the collapsed globules of the thermoresponsive copolymer above its LCST hinders the complete release of the drug which resulted in a reverse thermoresponsive drug release profile by the hybrid DDS

Body composition in coronary artery disease in KONKAN region of India-Is non- obesity an indicator of Coronary Artery Disease?

 Background India is witnessing a rising prevalence of non communicable diseases like diabetes, hypertension, coronary artery disease. This is attributed to rapid nutrition and lifestyle transition taking place since last 2 decades. Obesity is a well known independent risk factor   but very little information is available about role of leanness (low BMI). We investigated whether non-obesity could be an independent risk factor for Coronary artery disease in a rural clinic in KONKAN.    Methods  In a cross sectional study we studied body composition of 300 patients (207 men) who underwent Coronary angiography in a rural hospital in KONKAN region.  History of diabetes, hypertension and history smoking, tobacco chewing was recorded. Body composition was estimated using bio-impedance analyser. Based on results of coronary angiography, we generated a SYNTAX score derived by number of vessels involved and classified them into groups of severity of coronary artery disease (CAD).     Results There were 95 (31 %) diabetes and 189 (63%) hypertensive patients in the sample and 60% of them smoked or chewed tobacco. There were 43 (28 males) patients with SYNTAX score of zero. Among those with coronary artery disease (n=257) increasing severity of CAD   was associated with lower body weight, BMI, body fat percentage, and body fat mass and ejection fraction as against positive trend for lean mass and visceral fat.   Conclusion BMI, fat mass decreased with severity of CAD while lean mass and visceral fat increased. We observed high proportion of CAD in underweight and lean KONKAN adults. These findings need further investigations

Labour, industry and production in megalithic period (South Indian Iron Age): Nomadic, semi settled group or settled group?

There are above 1933 Megalithic Iron Age sites across south India; they include burial sites, habitation sites, habitation cum burial sites, Iron Age painting sites, isolated iron smelting localities near a habitation or burial. With the approach of economic archeology and sociotechnic perspective analyzing ceramics, metallurgy, burial monument (builder) and subsistent evidence (considering them as industries) that are found in the Megalithic burials as grave furnishers (The Material Archives Preserved in the Burial Monuments) from the background of Labour, Production and Industry that has economic imprints can be discussed on whether the Megalithic folks were nomadic, semi-settled or settled. This paper is an attempt to make a rough computation on the quantity of output that this culture might have in micro or in macro scale. This helps in understanding two aspects; one: whether they were nomadic, semisettled or settled at one location; two: diffusion versus indigenous development

Synthesis and Surface Treatment of Magnetite Nanoparticles for Tuning Hydrophobicity and Colloidal Stability

Post synthetic surface modification of magnetite nanoparticles synthesized by a modified co precipitation process was carried out with triethoxy terminated perfluoropolyether (PFPE) oligomers. The chemisorption of PFPE oligomers on the surface of magnetites was confirmed by ATR FTIR and TGA analyses. The efficiency of surface modification of the oligomer to prevent the aggregation of magnetite nanoparticles was studied with the dynamic light scattering technique by measuring the hydrodynamic diameter and polydispersity index of the surface treated nanoparticles, together with their zeta potential. Aggregation kinetics profiles were constructed for surface treated nanoparticles. The obtained data was compared with magnetite nanoparticles treated with critic acid, to assess the efficiency of the surface modification with the PFPE oligomers. The comparison showed that the bifunctional PFPE oligomer treated nanoparticles are characterized by improved colloidal stability and hydrophobicity