Superabsorbent sodium carboxymethyl cellulose membranes based on a new cross-linker combination for female sanitary napkin applications.

The main intent of this investigation was to retain the strength and superabsorbency of natural and non-toxic biodegradable polymers using an innovative combination of cross-linkers for application as the absorbent core of sanitary napkins. For this, sodium carboxymethyl cellulose (NaCMC) and starch were blend to form membranes by phase inversion and lyophilisation, using an optimized cross-linker combination of sodium trimetaphosphate (STMP) and aluminium sulphate (AlS). Optimal cross-linking of NaCMC and starch hampered membrane dissolution and disintegration, yielding a microtextured surface morphology. The membranes were biodegradable and yet possessed the requisite flexibility and mechanical strength for the proposed application, without compromise of superabsorbency. Lyophilised membranes possessed higher immediate water and blood sorption with ∼50% water retention capabilities when compared to the phase inversion technology. The results suggest that the developed membranes can be a cost-effective degradable alternative to the commercial polyacrylate-based nonbiodegradable sanitary products.

Cellular interactions of zinc oxide nanoparticles with human embryonic kidney (HEK 293) cells.

Zinc oxide nanoparticles (ZnO NPs) have potential biomedical, industrial and commercial applications. So they constantly come into contact with the body parts during applications. Safety concerns about ZnO NPs are increasing today and yet only few reports are available about their toxicity in kidney cells. It is very essential to analyze the toxicity on kidney because kidney plays a decisive role in nanoparticles excretion. Therefore, the present study focuses on the interaction of ZnO NPs with human embryonic kidney 293 (HEK 293) cells in vitro. The results showed that the cellular viability was much affected by ZnO NPs in a dose and time dependent manner. Oxidative stress increased the formation of reactive oxygen species (ROS), was found to be the prime mechanism of cytotoxicity. Formation of ROS eventually induced loss of mitochondrial membrane potential, lysosomal activity and nuclear condensation, which ultimately leads to apoptosis.

Seasonal characteristics of water-soluble inorganic ions and carbonaceous aerosols in total suspended particulate matter at a rural semi-arid site, Kadapa (India).

To better understand the sources as well as characterization of regional aerosols at a rural semi-arid region Kadapa (India), size-resolved composition of atmospheric particulate matter (PM) mass concentrations was sampled and analysed. This was carried out by using the Anderson low-pressure impactor for a period of 2 years during March 2013-February 2015. Also, the variations of organic carbon (OC), elemental carbon (EC) and water-soluble inorganic ion components (WSICs) present in total suspended particulate matter (TSPM) were studied over the measurement site. From the statistical analysis, the PM mass concentration showed a higher abundance of coarse mode particles than the fine mode during pre-monsoon season. In contrast, fine mode particles in the PM concentration showed dominance over coarse mode particle contribution during the winter. During the post-monsoon season, the percentage contributions of coarse and fine fractions were equal, whereas during the monsoon, coarse mode fraction was approximately 26 % higher than the fine mode. This distinct feature in the case of fine mode particles during the studied period is mainly attributed to large-scale anthropogenic activities and regional prevailing meteorological conditions. Further, the potential sources of PM have been identified qualitatively by using the ratios of certain ions. A high sulphate (SO4) concentration at the measurement site was observed during the studied period which is caused by the nearby/surrounding mining activity. Carbon fractions (OC and EC) were also analysed from the TSPM, and the results indicated (OC/EC ratio of ~4.2) the formation of a secondary organic aerosol. At last, the cluster backward trajectory analyses were also performed at Kadapa for different seasons to reveal the origin of sources from long-range transport during the study period.