Among the Weapons of Mass Destruction, chemical warfare (CW) is probably one of the most brutal created by mankind in comparison with biological and nuclear warfare. Chemical weapons are inexpensive and are relatively easy to produce, even by small terrorist groups, to create mass casualties with small quantities. The characteristics of various CW agents, general information relevant to current physical as well as medical protection methods, detection equipment available and decontamination techniques are discussed in this review article. A brief note on Chemical Weapons Convention is also provided.
The chemical factors influencing the selection of oviposition site by gravid females of various mosquito species have been the subject of numerous investigations. Recent studies have revealed this behaviour to be controlled by semiochemicals. Here we report studies on semiochemicals of egg origin and their effect on the ovipositional behaviour of Aedes aegypti. The compounds present in egg extracts of Ae. aegypti mosquitoes were isolated and identified by gas chromatography‐mass spectrometry. They were then evaluated for their effect on ovipositional behaviour against gravid females of Ae. aegypti mosquitoes at different concentrations. Gravid female Ae. aegypti were found to be sensitive to all the identified compounds: 6‐hexanolactone, methyl dodecanoate, dodecanoic acid, methyl tetradecanoate, tetradecanoic acid, methyl (Z)‐9‐hexadecenoate, methyl hexadecanoate (Z)‐9‐hexadecenoic acid, hexadecanoic acid, methyl (Z)‐9‐octadecenoate, methyl octadecanoate (Z)‐9‐octadecenoic acid and octadecanoic acid. Among them, dodecanoic and (Z)‐9‐hexadecenoic acids showed significant positive ovipositional response at different concentrations whereas all the esters showed deterrent/repellent ovipositional effect.
Oviposition pheromones specifically influence the females of many insects to lay eggs in the sites resulting in more egg deposition. A previous report describes the principal role of n-heneicosane (C(21)) identified and characterized from the larval cuticle of Aedes aegypti (L.) in attracting the gravid mosquitoes to oviposit in treated substrates among other chemical components. However, the means by which this compound is perceived by the females for oviposition has not been reported. In this study, we have recorded the peripheral olfactory responses from the antenna of Ae. aegypti from 10(-7) g to 10(-3) g doses of n-heneicosane. The EAG response of female mosquitoes increased in a dose-dependent manner with increasing stimulus strength. In the orientation assay using Y-maze olfactometer, female mosquitoes were attracted to the odor plume of 10(-6) g and 10(-5) g dose, while the higher dose of 10(-3) g plume enforced repellency to gravid mosquitoes. The response to oviposition substrates by gravid Ae. aegypti females differed across the range of concentrations of n-heneicosane under multiple choice conditions, larger number of eggs were deposited in 10 ppm (10 mg/l) solutions compared to lower and higher concentrations indicating 10 ppm was most attractive. Application of n-heneicosane at 10 ppm in breeding habitats will be a useful method to attract the gravid mosquitoes using ovitraps for surveillance and monitoring. The possible use of this compound in monitoring of mosquito population in endemic areas in relevance to integrated vector management strategies is discussed in detail.
in Wiley InterScience (www.interscience.wiley.com).Decontamination reactions of sulfur mustard and sarin were studied on the surface of titania nanotubes and the data were compared with that of bulk titania. Before the reaction studies, titania nanotube samples were made by using hydrothermal method and were characterized by scanning electron microscopy, N 2 BET, X-ray diffractometry, and thermogravimetry. Soon after that, titania nanotube samples were exposed to sulfur mustard and sarin separately at room temperature (308C) and the reactions were monitored by gas chromatography, whereas the reaction products were characterized by GC-MS. The data explore the role of hydrolysis reactions and surface reactions for the decontamination of both sulfur mustard and sarin.
Laboratory studies were carried out to observe the oviposition responses of Aedes aegypti (L.) and Aedes albopictus (Skuse) to several C21 fatty acid esters. The oviposition activity of these dengue and chikungunya vectors to the long-chain fatty acid esters of C21 length have not been reported earlier. From the multiple choice experiments on oviposition activity in standard mosquito cages, it was observed that compounds hexadecyl pentanoate, tetradecyl heptanoate and tridecyl octanoate presented significant oviposition repellent activity against the two mosquito species, while one compound propyl octadecanoate was found to attract A. aegypti to the treated oviposition substrate at 1- and 10-ppm concentrations. The possible utilization of these esters in integrated vector management is discussed.
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