Role of the prevalentAnophelesspecies in the transmission ofPlasmodium falciparumandP. vivaxin Assam state, north–eastern India

In north-eastern India, Anopheles minimus, An. dirus and An. fluviatilis are considered the three major vectors of the parasites causing human malaria. The role in transmission of the other Anopheles species present in this region is not, however, very clear. To examine the vectorial role of the more common anopheline mosquitoes, the heads and thoraces of 4126 female Anopheles belonging to 16 species (collected using miniature light traps set in human dwellings in a foothill village in the Jorhat district of Assam state) were tested, in ELISA, for the circumsporozoite proteins (CSP) of Plasmodium falciparum or the VK-210 and VK-247 polymorphs of P. vivax. Sixty-five pools of head-thorax homogenates, representing 10 different species of Anopheles, were found reactive, giving an overall minimum prevalence of infection (MPI) of 1.58%, with a 95% confidence interval (CI) of 1.21%-2.0%. Among the CSP-reactive pools of mosquitoes, 31% were positive only for P. falciparum, 45% only for P. vivax VK 247, 6% only for P. vivax VK 210, and 18% for both P. falciparum and P. vivax VK 247. The results indicate that not only the proven vector, An. minimus s.l. (MPI = 0.71%), but also several species of Anopheles previously considered unimportant in the epidemiology of malaria, especially An. aconitus (MPI = 3.95%), An. annularis (MPI = 5.8%), the An. hyrcanus group (MPI = 0.48%), An. kochi (MPI = 1.28%), the An. philippinensis-nivipes complex (MPI = 0.94%), and An. vagus (MPI = 3.87%), are important vectors in the foothills of Assam.

Characterization of the species formed during the extraction of thorium employing tri-n-butyl phosphate and N,N-dihexyl octanamide as extractants by laser desorption/ionization time-of-flight mass spectrometry

Laser desorption/ionization-time-of-flight mass spectrometry (LDI-ToF-MS) has been applied to identify and characterize the organic phase species formed during the extraction of thorium nitrate by 1.1 M tri-n-butyl phosphate (TBP) and N,N-dihexyl octanamide (DHOA) solutions in n-dodecane. The aqueous phase thorium concentrations (at 4M HNO3) have been suitably chosen to get Loaded organic phases with/without third-phase. The extracted species have been characterized for the first time using LDI-ToF-MS. The results show feasibility of the use of this technique for understanding the extraction mechanisms and third-phase formation behavior of different extractants. The different chemical species observed using this technique are consistent with those observed by small-angle neutron scattering (SANS).

Modified synthesis scheme for N,N´-dimethyl-N,N´-dioctyl-2,(2´-hexyloxyethyl) malonamide (DMDOHEMA) and its comparison with proposed solvents for actinide partitioning

N,N´-dimethyl-N,N´-dioctyl-2,(2´-hexyloxyethyl) malonamide (DMDOHEMA) has been synthesized by a relatively simpler route with a better yield than the conventional procedures for the synthesis of pentaalkyl substituted diamides. The proposed route replaces the use of acid chlorides and brominating agents (corrosive in nature) by acid diester and p-toluene sulphonyl (tosyl) chloride, respectively. The later easily replaces hydrogen from primary OH group of the 3-oxanonyl side chain and relatively less corrosive. The synthesized product has been tested for the extraction behavior of 241Am, Np, Pu as pure tracers as well as under Pressurized Heavy Water Reactor (PHWR) Simulated High-Level Waste (SHLW) conditions. The stoichiometries of extracted species of Np(IV), Pu(IV), and Am(III) from 3 M HNO3 using varying concentrations of DMDOHEMA in n-dodecane has been determined. The effect of the nature of mineral acid (viz. HCl, HNO3, and HClO4) on the extraction of Am(III) has also been investigated employing DMDOHEMA and N,N´-dimethyl-N,N´-dibutyl-tetradecyl malonamide (DMDBTDMA) as extractants and explained in terms of the aggregation behavior of diamides. The performance of DMDOHEMA has been evaluated vis-à-vis other proposed extractants for actinide partitioning under PHWR-SHLW conditions.

Supported liquid membrane transport studies on Am(III), Pu(IV), U(VI) and Sr(II) using irradiated TODGA

Transport behaviour of actinides viz. Am(3+), Pu(4+) and UO(2)(2+) was investigated from nitric acid feed conditions using PTFE (polytetrafluoroethylene) flat sheet supported liquid membranes (SLM) containing an irradiated solvent system comprising of N,N,N',N'-tetra-n-octyldiglycolamide (TODGA) as the carrier extractant and N,N-di-n-hexyloctanamide (DHOA) as the phase modifier. The present studies were carried out in order to understand the effect of irradiation on the long term reusability of the SLM and the decontamination behaviour in the absorbed dose range of 0-100 MRad. The studies using irradiated carrier included those with irradiated TODGA without any phase modifier and with 0.1M as well as 0.5M DHOA as the phase modifier. Transport behaviour of all the metal ions were found to be seriously affected with increasing radiation dose which was reflected in the decreasing percentage transport (%T) as well as permeability co-efficient (P) values. Though Sr(II) transport was quite significant with all the three unirradiated solvent systems, it was surprisingly low (<5%) when solvents exposed to 100 MRad dose were used in the SLM. Separation factors (S.F.) of the actinides over Sr(II) were calculated and were found to increase at higher radiation doses suggesting possibility of getting better decontamination on prolonged use of the supported liquid membrane system.

Variation in effects of four OP insecticides on photosynthetic pigment fluorescence of Chlorella vulgaris Beij

Effects of the insecticides quinalphos, chlorfenvinphos, dimethoate and phorate on photosystem activity of Chlorella vulgaris were investigated by different chlorophyll fluorescence measurements. Exposure to each of the insecticides increased the proportion of inactivated PS II reaction center. Quinalphos and chlorfenvinphos caused OJIP fluorescence reduction at all levels by decreasing the proportion of Q(A)-reducing PS II reaction centers (RCs). The other two insecticides affected OJIP fluorescence rise by hindering the electron transport beyond Q(A). Insecticide treatment resulted in decrease of the density of active RC and performance indices (PI) by enhanced dissipated energy flux per active RC. Antenna size was severely minimized by quinalphos and chlorfenvinphos treatment whereas other two insecticides had no such effect. Each insecticide treatment caused increase of photosystem antenna/core and PS II/PS I fluorescence ratios. Quinalphos and chlorfenvinphos affected the donor sides of photosystems whereas dimethoate and phorate inhibited electron transfer beyond Q(A) (acceptor side).