Synergistic mosquito-repellent activity of Curcuma longa, Pogostemon heyneanus and Zanthoxylum limonella essential oils

SummaryMosquito repellents play an important role in preventing man–mosquito contact. In the present study, we evaluated the synergistic mosquito-repellent activity of Curcuma longa, Pogostemon heyneanus and Zanthoxylum limonella essential oils. The mosquito repellent efficacies of three essential oils were evaluated separately and in combination under laboratory and field conditions. N,N-Diethylphenylacetamide (DEPA) and dimethylphthalate (DMP) were used for comparison of the protection time of the mixture of essential oils. At an optimum concentration of 20%, the essential oils of C. longa, Z. limonella and P. heyneanus provided complete protection times (CPTs) of 96.2, 91.4 and 123.4min, respectively, against Aedes albopictus mosquitoes in the laboratory. The 1:1:2 mixture of the essential oils provided 329.4 and 391.0min of CPT in the laboratory and field trials, respectively. The percent increases in CPTs for the essential oil mixture were 30 for DMP and 55 for N,N-diethylphenylacetamide (DEPA). The synergistic repellent activity of the essential oils used in the present study might be useful for developing safer alternatives to synthetic repellents for personal protection against mosquitoes

Information Systems Security8th International Conference, ICISS 2012, Guwahati, India, December 15-19, 2012. Proceedings /

XVI, 353 p. 96 illus.online resource

2,7-Dichlorofluorescein, a fluorescent sensor to detect Cd²⁺ over Na⁺, K⁺, Ca²⁺, Cu²⁺, Ni²⁺ and Zn²⁺

1617-1620The intensity of the fluorescent emission spectra of 2,7-dichlorofluorescein (510-640 nm) on excitation with 350 nm enhances on interaction with Cd2+ ions. Minor enhancement is observed with Na+ and Zn2+ ions, while no enhancement at all in fluorescence is observed with K+, Ca2+, Cu2+ and Ni2+. The enhancement in the fluorescence is explained on the basis of photoinduced electron transfer (PET) mechanism due to the binding of two Cd2+ ions to 2,7-dichlorofluorescein (log b = 3.80)

REMOTE SENSING AND GIS BASED LAND-USE PLANNING IN “SATER MIANAR HOUR ” WET LAND ECOSYSTEM IN TRIPURA STATE OF INDIA FOR SUSTAINABLE DEVELOPMENT

In the state of Tripura, in India, agriculture contributes about 64 % of the total employment and about 48 % of the state’s domestic product. Growing population and decreasing per capita land availability entails that the available land must be utilized effectively. With this broad objective, the study team took up an integrated study of “Sater Mianar Hour”- an erstwhile wetland ecosystem being used for rice cultivation. The study was basically aimed at improving the productivity of the wetland area in catchment level. Major problems of the wetland ecosystem are siltation of the natural drainages locally called charras, gradual rise of the major river bed resulting in back flow into the feeder channels causing water stagnation and flooding, mono-crop agriculture with rice alone as the dominant crop etc. Major objective of the study was to prepare land-use plan for sustainable development of the area in catchment level with inputs from sub-watersheds prioritization and Sub-surface water potential in various landforms and litho-types of the study area, where sub-watersheds were prioritized based both field and remote sensing parameters such as various parameters of drainage morphometry such as drainage density, circularity ratio etc, slope, Soil brightness index (SBI), nomalised difference vegetation index (NDVI) etc. Data from LISS III (multispectral) and LISS-IV (mono) of IRS-P6 satellite and soil maps from NBSSLUP were used to map the current land use, geomorphology, ground water prospective zones. The entire rice ecosystem has been delineated into twenty micro watersheds and prioritized into four categories such as very high, high, medium and low for taking up developmental plans on priority. It is found that most of the study area is good to very good in ground water prospect that can be used extensively during Rabi and summer season crop growing periods after carrying out qualit

Disappearance of An. minimus and An. dirus from Certain Malaria Endemic Areas of Assam, India

Background: Orang Primary Health Centre (OPHC) and Balipara Primary Health Centre (BPHC) of Assam (India) report mosquito borne diseases annually. Current study was performed to ascertain the prevalence of known malaria and Japanese Encephalitis (JE) vectors and their possible role in disease transmission. Methods: Malaria epidemiological data for 2006–2010 and JE data for 2008–2013 of Assam, India were obtained from the health authority. Mosquitoes were collected using CDC light traps and identified morpho-taxonomically. Results: Plasmodium falciparum cases (81.5%, 95% CI= 72.0–91.1) were statistically higher in OPHC (P< 0.0001, t= 8.0) during the recent years. There was 4.4 folds rise in the confirmed acute encephalitis syndrome (AES) and 3.2 folds increase in the confirmed JE cases during 2013 as compared to 2008. Altogether 9,218 mosquito specimens (PTND= 153.6), comprising of 44.1% anophelines (PTND= 67.7), 42.3% culicines (PTND= 65.0) and 9.5% manso­nia (PTND= 14.6) were recorded. In BPHC, An. vagus was recorded in high density (P< 0.0001), whereas Cx. quin­quefasciatus was the predominant JE vector (P= 0.04). In OPHC, among the known malaria vectors, the density of An. annularis was significantly high (P< 0.0001). However Culex bitaeniorhynchus was the predominant known JE vector (P< 0.0001) followed by Cx. quinquefasciatus. Conclusion: Even in the absence of known efficient vectors, many Anopheles species are still involved in malaria transmission. There was disappearance of An. minimus and An. dirus and establishment of An. annularis, An. vagus and An. philippinensis/nivipes mosquitoes in study area