Environmental exposure to lead and its correlation with biochemical indices in children

Lead is a global concern because of its ubiquity in the environment and known to be associated with abnormal neurobehavioral and cognitive development of young children. There is no study from India to describe a composite profile of blood lead and its biochemical influences in children. The present study was aimed at determining the proportion of children with >10 mug/dL blood lead levels (BLLs), association between BLLs, and sociodemographic characteristics, if any, and alterations in biochemical indices in the blood as an underlying mechanism of lead intoxication. A total of 62 children (4--12 y) of Lucknow and nearby areas were recruited to determine BLLs, delta-amimolevulinic acid dehydratase (delta-ALAD) activity, catalase (CAT) activity, and malondialdehyde (MDA) and glutathione (GSH) levels in the blood. Mean level of blood lead was 7.47+/-3.06 microg/dL (2.78--15.0) and 29%-exceeded 10 microg/dL, CDC intervention level. The BLLs were found to be significantly influenced by social status, area of residence, source of water supply, maternal educational status (p<0.001), type of house, and proximity to traffic density (p<0.01). delta-ALAD was significantly lower in the group of children with BLLs 11.39+/-1.39 microg/dL when compared to children with BLLs 7.11+/-1.25 microg/dL and 3.93+/-0.61 microg/dL (p=0.0007, 0.0005, respectively). However, CAT activity was higher in the groups of children with higher blood levels than with lower BLLs (p=0.0159, 0.0001, respectively). There was an increase in MDA level with a concomitant decrease of GSH in children with BLLs 11.39+/-1.39 microg/dL compared with those of children with BLLs 7.11+/-1.25 microg/dL and 3.93+/-0.61 microg/dL (p=0.0001, 0.0002, and p=0.0001, respectively). There was statistically significant correlation of BLLs with delta-ALAD (r=-0.44, p=0.00035), MDA (r=0.46, p=0.00018), GSH (r=-0.62, p=0.00001), and CAT (r=0.44, p=0.00035). Significantly, CAT activity, MDA, and GSH levels were in turn, found to be correlated with delta-ALAD (r=-0.45, p=0.00024; r=-0.43, p=0.00053; r=0.43, p=0.00053, respectively). Results of the present study indicate a declining trend of BLLs in children when compared with those reported from metropolitan cities of India when leaded gasoline was in practice and that the BLLs were significantly associated with biochemical indices in the blood which have the potential to be used as biomarkers of lead intoxication.     

The characterisation of friction stir welding process effects on stiffened panel buckling performance

The introduction of advanced welding methods as an alternative joining process to riveting in the manufacture of primary aircraft structure has the potential to realise reductions in both manufacturing costs and structural weight. However, welding processes can introduce undesirable residual stresses and distortions in the final fabricated components, as well as localised loss of mechanical properties at the weld joints. The aim of this research is to determine and characterise the key process effects of friction stir welding assembly methods on stiffened panel static strength performance. Utilising experimentally validated finite element modelling methods, it is demonstrated that welding induced residual stresses have a significant influence, and that collapse behaviour is less sensitive to advanced process effects and process effect magnitudes than panel initial buckling behaviour.     

A new mathematical model to evaluate simazine removal in three different immobilized-biomass reactors

A new mathematical model based on the cinetical Langmuir equation is developed to interpret and predict the effectiveness of simazine (SZ) removal in immobilized-biomass reactor (IBR), to consider herbicide-support affinity (Cx), and herbicide-cell affinity (Cy). Three solid supports: sepiolite monolith, granular sepiolite, and alginate were used in pilot-scale reactors that were inoculated with Klebsiella planticola DSZ. The abiotic process was analysed by measuring the SZ sorption capacity of the reactor supports. Sepiolite monolith showed the maximum value for herbicide-support affinity (28.02+/-0.9%). The effectiveness of the biotic process was estimated considering the formation of biomass and SZ biodegradation. Granular sepiolite showed either higher affinity with SZ and viability rate (0.90) throughout the process, and SZ removal rate was 3.39+/-0.06 mg/h. The mathematical model presented in this paper provides useful insights into the interpretation of experimental data as well as prediction for the implementation of biological reactors.     

Congratulations to Valerii Viktorovich Mikheev

Anniversaries and Memorable Dates

Congratulations to Valerii Viktorovich Mikheev Candidate of Technical Sciences, honorable builder of the Russian Federation, and recipient of the prize awarded by the Council of Ministers of the USSR     

Does oyster size matter for modelling trace metal bioaccumulation?

The aim of this study was assessing whether trace metal bioaccumulation models for oysters need to account for the effect of size-structured demography. To achieve this, we used a Bayesian generalised additive mixed modelling (BGAMM) approach. This nonparametric regression approach allowed us to estimate potentially nonlinear size effects of the oysters as well as random and structured spatial effects. Native oysters were collected from ten locations around the shoreline of Moreton Bay, a subtropical estuary in southeast Queensland, Australia. The soft-tissue of these sampled oysters were weighed (dry weight basis) and then analysed for Al, Cu, Fe, Mg, Mn and Zn. Of the six trace metals analysed, only Mg was found to have a significant (negative) effect of soft-tissue mass. The correlated spatial effects for Cu, Mn and Zn indicated that the source of these trace metals in the oysters was from anthropogenic inputs while the correlated spatial effects for Al and Mg indicated natural inputs. The correlated spatial effect for Fe was characterised by 'hotspot' concentrations in regions of Moreton Bay where algal blooms have previously occurred and consequently oysters might be useful as an indicator of algal blooms in the Bay. Overall, the absence of an observed size effect for five of the six trace metals indicates that bioaccumulation models do not necessarily need to account for size-structured demography therefore enabling simpler models to be used.     

The use of desorbing agents in electrodialytic remediation of harbour sediment

Electrodialytic removal of Cu, Zn, Pb and Cd from contaminated harbour sediment was made with the emphasis of testing the effectiveness of different desorbing agents: HCl, NaCl, citric acid, lactic acid, ammonium citrate and distilled water. Extraction experiments with the desorbing agents were made prior to the electrodialytic experiments. The extractions showed that HCl was most efficient for metal desorption, probably due to the low pH and complexation with chloride. The metals were not extracted by distilled water. However, in the electrodialytic experiments, the removal was high when using distilled water and the desorbing agents did generally not enhance the heavy metal removal compared to distilled water. The only exception was with lactic acid, where the Cu removal was 20% higher compared to the other desorbing agents. The removal was 48% Cu, 80% Zn, 96% Pb and 98% Cd, when using distilled water. Metal speciation with the different desorbing agents was simulated with the geochemical model Visual MINTEQ version 2.15. Variations in the Cl concentration were found to be of crucial importance since it influences the formation of metal chlorocomplexes, especially uncharged species. All the acidic desorbing agents were predicted to form mostly cationic species, which was in agreement with the removal direction in the electrodialytic remediation experiments.     

Wind loads on attached canopies and their effect on the pressure distribution over arch-roof industrial buildings

Arch-roof industrial buildings are very wind sensitive. The current aerodynamic coefficients in wind codes do not contemplate the possibility of existence of canopies attached to the buildings. This paper presents the results of an investigation on the influence exerted by canopies on the static wind actions on arch-roof industrial buildings. Six scale models of these arch-roof buildings were tested, with five types of canopies attached. Three of these canopies were instrumented and the static wind pressures were measured. The tests were done at the boundary layer wind tunnel of the Universidade Federal do Rio Grande do Sul. The results show that the aerodynamic coefficients for the roof are not affected by the canopies, in the case of axial incidence. However, the influence on the pressure distribution is noticeable for wind incidence perpendicular to the main axis of the arch roofs and for other incidences as well. This influence is discussed in the paper. The aerodynamic coefficients for the design of the arch-roofs, with and without the attached canopies are given. Aerodynamic coefficients for design of the canopies are also suggested. Furthermore, the paper discusses the relation between the magnitude of the canopy design forces and the canopy width, as well as the relation between the canopy height location and the height of the building wall. The results were compared with design recommendations from previous work of Jancauskas and Holmes (in: US National Conference on Wind Engineering, Proceedings, Texas Tech University, Lubbock, 1985) and Jancauskas and Eddleston (in: International Conference on Wind Engineering, Fotodruck J. Mainz, Aachen, 1987).     

Charge transport in grain size tuned CuO nanocrystal films

Journal of Electroceramics - CuO nanocrystal (NC) films of different grain sizes were synthesized through the oxidation of Cu films deposited by controlling the supersaturation in the deposition...     

The Effect of Energy-Supply and Performance Indicators on the Performance of Traction-Resource Management Centers

Russian Electrical Engineering - This paper presents the results of a study of the effect of the characteristics of the traction power-supply system on the indicator of the energy supply of...