Nutrition morbidity interactions in pre-school children.

Background & objectives: Research studies in the 1970s reported that in pre-school children, undernutrition increased the risk of infections and infections aggravated undernutrition. Over decades, there has been a reduction in prevalence of undernutrition and improvement in access to healthcare for treatment of infections. A mixed longitudinal study was undertaken to assess whether over time there were any changes from the earlier reported effect of undernutrition prior to infection on the risk of morbidity and effect of morbidity on nutritional status in pre-school children. Methods: Pre-school (0-59 months of age) children from urban low- and middle-income families whose parents were willing to allow their participation in the study were enrolled. Information on sociodemographic profile of the families was collected at enrolment. Weight of all children and length in infants were recorded every month; length/height in children 12-59 months of age was recorded once in three months. Morbidity information was collected through fortnightly visits. Results: 3888 pre-school children were followed up in 74636 home visits. Among these children, underweight and wasting were associated with a small increase in risk of infections. The odds ratio for risk of infection for underweight children was 1.09 (95% CI: 1.02 to 1.16) and for wasting was 1.18 (95% CI: 1.08 to 1.29). The deterioration in Z scores for weight-for-age and body mass index-for-age in children during illness and convalescence was small but significant (P<0.001). Interpretation & conclusions: The increased risk of infections in undernourished children living in overcrowded tenements in areas with poor environmental hygiene was not significant, perhaps because the risk of infection in normally nourished children was also high. The deterioration in nutritional status following infection was small because of the ready access to and utilization of health and nutrition care.

Structural, magnetic, and dielectric properties of solution combustion synthesized LaFeO3, LaFe0.9Mn0.1O3, and LaMnO3 perovskites.

Nanocrystalline LaFeO3, LaFe0.9Mn0.1O3, and LaMnO3 perovskites have been synthesized by a novel solution combustion route, in which oxalyl dihydrazide (ODH) has been used as a fuel. These materials have been characterized using several physicochemical techniques. LaFeO3 and LaFe0.9Mn0.1O3 adopt an orthorhombic structure and LaMnO3 crystallizes in a rhombohedral structure as demonstrated by X-ray diffraction (XRD) patterns. The microporous character of the materials due to huge gas evolution during preparation has been revealed by field emission scanning electron microscopy (FESEM) images. Corresponding elements are present in stoichiometric amounts in all perovskites as revealed by energy dispersive X-ray spectroscopy (EDXS) analyses. X-ray photoelectron spectroscopy (XPS) studies demonstrate the presence of La3+, Fe2+, Fe3+, Mn3+, and Mn4+ species in the respective materials. Absorption bands in the frequency range of 500-600 cm-1 related to Fe-O/Mn-O bonds in FeO6/MnO6 octahedra are observed in Fourier transform infrared (FTIR) spectra. Raman spectroscopy depicts symmetric modes related to metal-oxygen bonds in orthorhombic and rhombohedral structures. Weak ferromagnetism has been observed in LaFeO3 and LaFe0.9Mn0.1O3 which is due to superexchange interaction between the magnetic cations. However, LaMnO3 shows paramagnetic behavior. The electrical characteristics exhibit the lowest dielectric loss for magnetic LaFeO3 among the LaFeO3, LaFe0.9Mn0.1O3, and LaMnO3 perovskites studied here.

Effect of Cerium Oxide Nanostructures on CO Oxidation.

Cerium oxide particles with different morphologies, namely nanoparticles, nanofibers, nanocubes, and rice grains have been prepared by simple chemical routes. The shape and size of the synthesized morphologies have been studied using field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM). X-ray diffraction (XRD) and selected area electron diffraction (SAED) techniques have been used to determine their crystal phases. Both nanoparticles and nanocubes of cerium oxide exclusively crystallize in fluorite structure of CeO2 as observed in XRD patterns, whereas nanofibers and rice grains are characterized by the presence of CeO2, Ce2O3, and Ce(OH)3 phases. X-ray photoelectron spectroscopy (XPS) has been employed to evaluate Ce species present in the different cerium oxide morphologies and to estimate their relative surface concentrations. As evident from Ce 3d core level spectra cerium oxide nanoparticles and nanocubes are basically CeO2 having Ce in the +4 oxidation state along with some amount of Ce3+ species. In contrast, Ce is in +3 oxidation state on its surface in cerium oxide nanofibers and rice grains that contain intermediate phases like Ce2O3 and Ce(OH)3 as endorsed by XRD patterns. CO oxidation has been carried out over these cerium oxide morphologies and among all morphologies lowest temperature CO oxidation has been demonstrated by the nanocube morphology.

Solution combustion synthesis, characterization, magnetic, and dielectric properties of CoFe2O4 and Co0.5M0.5Fe2O4 (M = Mn, Ni, and Zn).

Nanocrystalline CoFe2O4 and Co0.5M0.5Fe2O4 (M = Mn, Ni, and Zn) ferrites were prepared by the solution combustion method using oxalyl dihydrazide as a fuel. These materials were characterized by several physicochemical techniques. X-ray diffraction (XRD) patterns indicate the cubic spinel structure of these ferrites. Field emission scanning electron microscopy (FESEM) images demonstrate the microporous nature of the materials because of the large amount of gas production during their synthesis. High resolution transmission electron microscopy (HRTEM) images show lattice fringes corresponding to the {220} and {311} planes of the spinel structure. Fourier transform infrared (FTIR) spectra exhibit absorption bands around the 500-600 cm-1 wavenumber region which are related to metal-oxygen bonds with tetrahedral coordination. Symmetric and asymmetric stretching and symmetric bending modes associated with tetrahedral and octahedral cations present in the spinel structures have been assessed by Raman spectroscopy. X-ray photoelectron spectroscopy (XPS) studies demonstrate the presence of Co2+, Mn2+, Ni2+, Zn2+, and Fe3+ in tetrahedral and octahedral coordinations in these ferrites. Co0.5Zn0.5Fe2O4 is observed to show the highest saturation magnetization among all these materials. The dielectric measurements reveal that the dielectric constant and loss values decrease with an increase in frequency and the ac conductivity increases at higher frequencies due to mobilization of the charge carriers.

Enhanced microwave absorption properties of PMMA modified MnFe2O4-polyaniline nanocomposites.

A manganese based spinel ferrite, chemically modified with polymethyl methacrylate (PMMA) and polyaniline (PANI) are synthesized and their composites are used as electromagnetic interference (EMI) shielding materials. X-ray diffraction studies show that the as-prepared manganese ferrite crystallizes in a cubic spinel structure. The particles are highly agglomerated and nanocrystalline as indicated by transmission electron microscopy. Manganese exists in +2 and +4 oxidation states and Fe in +2 and +3 oxidation states. Modified manganese ferrite and polyaniline composites in different weight ratios are evaluated for their EMI shielding properties. It is observed that composites containing the PMMA modified ferrite show enhanced total shielding effectiveness (SET) compared to those containing the unmodified ferrite in the X band frequency range (8-12 GHz). The optimized ratio of the PMMA modified ferrite and PANI demonstrates SET values as high as ∼44 dB in the X band frequency range.

Effect of particle size and dopant concentration on photophysical properties of Eu3+-doped rare earth oxysulphide phosphor coatings.

Europium-doped rare-earth oxysulphides (red phosphors) are often used as reference luminophore in pyrene-based pressure sensor coatings for aerodynamic applications. Different red phosphor samples were characterized for their particle size, chemical composition, photoluminescent properties and temperature sensitivity. The red phosphor samples were characterized using energy-dispersive X-ray spectroscopy (EDX) for elemental analysis and scanning electron microscopy (SEM) for morphology and particle size measurement. The particle size was in the range of 1.5-5.7 µm with morphology of hexagonal or spherical shape. It was found that phosphor with higher europium content exhibited higher luminescent emission intensity. The phosphor coatings were prepared by spraying a dispersion of the material in silicone resin. Smooth coatings were obtained by using phosphor samples with smaller particle size. Upon 334 nm excitation, the coatings showed characteristic luminescence 5D0→7FJ (J=0, 1, 2, 3, 4) of the Eu3+ ions. The electronic transition located at 626 nm (5D0→7F2) of Eu3+ ions was stronger than the magnetic dipole transition located at 595 nm (5D0→7F1). Luminescence decay curves obeyed double exponential behaviour. The phosphor samples showed temperature sensitivity of -0.012 to -0.168%/°C in the temperature range of 25-50 °C.

Fabrication of superhydrophobic sol-gel composite films using hydrophobically modified colloidal zinc hydroxide.

A superhydrophobic sol-gel composite film was fabricated by incorporating hydrophobically modified colloidal zinc hydroxide (CZH) in sol-gel matrix. CZH was prepared by controlled precipitation and modified by treatment with stearic acid. The concentration of stearic acid and stirring time were optimized to obtain modified CZH with very high water contact angle (WCA) of 165 degrees and sliding angle (SA)<2 degrees . X-ray diffraction (XRD) analysis has shown that the crystal structure of CZH was mainly composed of epsilon-zinc hydroxide and the modified CZH indicated the presence of zinc stearate. The modified CZH film exhibited a microstructure which resembled clusters of interconnected rods creating roughness on the film surface. The modified CZH suspension was dispersed in an acid-catalyzed sol of tetraethoxysilane (TEOS) and methyltriethoxysilane (MTEOS) and spray-coated on glass slides to prepare sol-gel composite coatings. The concentration of CZH in the composite film was optimized to obtain superhydrophobic surfaces. FTIR spectrum also confirmed the presence of zinc stearate in the composite film. The method is simple and cost-effective and does not involve any expensive chemicals or equipments.