Effect of fatty acids and oils on photodegradation of azadirachtin-A

Azadirachtin-A on exposure to UV-light (254 nm) as a thin film on glass surface gave a isomerised (Z)-2-methylbut-2-enoate product. Half-life of azadirachtin-A as thin film under UV light was found to be 48 min. Azadirachtin-A was irradiated along with saturated and unsaturated fatty acids, and fatty oils under ultra-violet light as thin film. Saturated fatty acid increased the rate of photodegradation of azadirachtin-A, whereas unsaturated fatty acids such as oleic, linoleic and elaidic acid reduced the rate of degradation. Castor, linseed and olive oil accelerated the rate of degradation, whereas neem oil showed no or little change in the rate of degradation of azadirachtin-A. None of these fatty acids and fatty oils were effective in controlling the rate of degradation of azadirachtin-A under UV-light as thin film.     

Challenges for physical characterization of silver nanoparticles under pristine and environmentally relevant conditions

The reported size distribution of silver nanoparticles (AgNPs) is strongly affected by the underlying measurement method, agglomeration state, and dispersion conditions. A selection of AgNP materials with vendor-reported diameters ranging from 1 nm to 100 nm, various size distributions, and biocompatible capping agents including citrate, starch and polyvinylpyrrolidone were studied. AgNPs were diluted with either deionized water, moderately hard reconstituted water, or moderately hard reconstituted water containing natural organic matter. Rigorous physico-chemical characterization by consensus methods and protocols where available enables an understanding of how the underlying measurement method impacts the reported size measurements, which in turn provides a more complete understanding of the state (size, size distribution, agglomeration, etc.) of the AgNPs with respect to the dispersion conditions. An approach to developing routine screening is also presented.     

Assessment of alpha activity of building materials commonly used in West Bengal, India

This paper, reports for the first time, an extensive study of alpha activity of all widely used building materials (plaster of Paris, stone chips, marble, white cement, mosaic stone, limestone, sand, granite, cement brick, asbestos, red brick, cement tile, ceramic tile and ceramics) in West Bengal, India. The alpha activities have been measured using Solid State Nuclear Track Detector (SSNTD), a very sensitive detector for alpha particles. The samples were collected from local markets of Kolkata. The measured average alpha activities ranged from 22.7+/-2.5 to 590.6+/-16.8Bqkg(-1). The alpha activity of ceramic tiles was highest and provides additional data to estimate the effect of environmental radiation exposure on human health.     

Comparisons of polybrominated diphenyl ethers levels in paired South Korean cord blood, maternal blood, and breast milk samples

Polybrominated diphenyl ethers (PBDEs), commonly used flame retardants, have been reported as potential endocrine disruptor and neurodevelopmental toxicants, thus giving rise to the public health concern. The goal of this study was to investigate the relationship between umbilical cord blood, maternal blood, and breast milk concentrations of PBDEs in South Korean. We assessed PBDE levels in paired samples of umbilical cord blood, maternal blood, and breast milk. The levels of seven PBDE congeners were measured in 21 paired samples collected from the Cheil Woman’s Hospital (Seoul, Korea) in 2008. We also measured thyroid hormones levels in maternal and cord blood to assess the association between PBDEs exposure and thyroid hormone levels. However, there was no correlation between serum thyroxin (T4) and total PBDEs concentrations. The total PBDEs concentrations in the umbilical cord blood, maternal blood, and breast milk were 10.7 ± 5.1 ng g⁻¹ lipid, 7.7 ± 4.2 ng g⁻¹ lipid, and 3.0 ± 1.8 ng g⁻¹ lipid, respectively. The ranges of total PBDE concentrations observed were 2.28-30.94 ng g⁻¹ lipid in umbilical cord blood, 1.8-17.66 ng g⁻¹ lipid in maternal blood, and 1.08-8.66 ng g⁻¹ lipid in breast milk. BDE-47 (45-73% of total PBDEs) was observed to be present dominantly in all samples, followed by BDE-153. A strong correlation was found for major BDE-congeners between breast milk and cord blood or maternal blood and cord blood samples. The measurement of PBDEs concentrations in maternal blood or breast milk may help to determine the concentration of PBDEs in infant.     

Monitoring of multiple drug-resistant pathogens in a selected stretch of Bay of Bengal,India

The present work aims at identification of multiple drug-resistant pathogenic bacteria in a selected stretch, namely, Puri on the Bay of Bengal, India. Six stations at the coast of Puri were selected and samples of water and sediment were collected during the winter of 2008 and 2009 for this study. Thirty-eight pathogenic bacteria were isolated and identified from both the water and the sediment of 6 fixed stations (PU-1a, PU-1b, PU-2, PU-3, PU-4, and PU-5). The identified pathogens were Escherichia coli, Vibrio cholerae, Vibrio parahaemolyticus, Klebsiella pneumoniae, Staphylococcus aureus, Enterococcus faecalis, Pseudomonas aeruginosa, and Proteus mirabilis. Antibiotic sensitivity of the isolated bacteria was studied by using 12 selected antibiotics, commonly used for the medication of human beings and animals. The isolated pathogens from both the water and the sediment samples showed lowest resistance to chloramphenicol (C-30 μg) where as the pathogens showed highest level of resistance to ampicillin (10-μg) among the antibiotics used for the study. Among the isolated pathogens E. faecalis (PU-1a), P. aeruginosa (PU-2 and PU-3), E. coli (PU-3 and PU-4), and K. pneumonia (PU-4) showed resistance to more than four antibiotics. Out of the isolated species, 57.8% pathogens were multi-drug resistant. Antibiotic resistance indexes of all the stations were calculated and found to be in the range of 0.066 to 0.083.     

Entomotoxicity and biosafety assessment of PEGylated acephate nanoparticles: A biologically safe alternative to neurotoxic pesticides

This is a report of an experimental study on a nanoencapsulation of the organophosphate acephate. Acephate was encapsulated in polyethylene glycol, using a simple, easy-to-replicate method that required no special equipment or conditions. The nanoencapsulation (nanoacephate) was characterized and its bioefficacy as compared to the regular commercial acephate was tested. The biosafety of the new compound was also tested on a murine model. Our new nanoencapsulation scored over the regular variety on all counts. It was found to successfully incorporate the active pesticidal component, acephate and this compound retained greater functional integrity over time as a nanoencapsulation. It was significantly more efficacious than the regular variety. It was biosafe when tested on murine model. We have reason to believe that this nanoencapsulation would allow the use of an organophosphate in a more targeted manner, thereby making it a cost-effective and eco-friendly alternative to the regular variety in use now.     

Innovations in applications and prospects of bioplastics and biopolymers: a review

Environmental Chemistry Letters - Non-biodegradable plastics are continually amassing landfills and oceans worldwide while creating severe environmental issues and hazards to animal and human...