Infrared spectroscopy and elastic properties of nanocrystalline Mg-Mn ferrites prepared by co-precipitation technique.

Nanoparticles having particle size in the range 25-40 nm for compositions x = 0.0, 0.2, 0.4 and 0.5 of Mg(x)Mn(1-x)Fe2O4 spinel ferrite system have been prepared by chemical co-precipitation route. The microstructure, infrared spectral and elastic properties have been studied by means of energy dispersive analysis of X-rays (EDAX), transmission electron microscopy (TEM), X-ray diffraction (XRD) and infrared spectroscopic (IR) measurements, before (W) and after high temperature annealing A(w). The force constants for tetrahedral and octahedral sites determined by infrared spectral analysis, lattice constant and X-ray density values by X-ray diffraction pattern analysis; have been used to calculate elastic constants. The magnitude of force constant and elastic moduli for nanocrystalline W-samples are found to be larger as compared to coarse grained A(w)-samples. The results have been explained in the light of redistribution of cations and as a result change in mean ionic charge for such cationic sites, elastic energy and grain size reduction effect of Nanoparticles.

Monoclonal antibody based ELISA : an effective diagnostic tool for the diagnosis of falciparum malaria.

An enzyme-linked immunosorbent assay (ELISA) system based on the monoclonal antibodies (F2W22C1) originated from Thai strains of P.falciparum in mice models and polyclonal antibodies raised against Nepali strains of P.falciparum in rabbit models was developed for the detection of local Nepali strain of P.falciparum antigens in red cell lysates. The monoclonal-polyclonal antibody based indirect ELISA developed for the detection of P.falciparum antigens was specific since it was positive only with P.falciparum infected erythrocytes and negative when blood from forty healthy individuals collected from the malaria non-endemic areas and forty P.vivax infected erythrocytes were tested. When the test was applied to microscopically confirmed 154 falciparum infected blood samples collected from Dhanusha district, Nepal; the assay detected only 138 out of 154 P.falciparum samples indicating the sensitivity of the test to be 89.6%. When the assay was used to detect forty samples from the patients of unknown origin of fever other than the malaria collected from the malaria endemic areas, all forty samples were negative with the assay system. A significant correlation was observed (r = 0.872; p = 0.013) in between the parasitemia and the O.D. values obtained from the MAb-PAb based indirect ELISA. The test developed using monoclonal antibodies raised against Thai P. falciparum isolates and the polyclonal antibodies raised against native Nepali strains of P.falciparum offered high degrees of sensitivity and specificity. However, the test requires further evaluation with higher number of samples; requires further improvement in sensitivity; before commercial use of the test in patient care.