The effect of solvents on metal ion adsorption by the alga Chlorella vulgaris

The dead dried alga, Chlorella vulgaris, was used for metal ion sequestering. The uptake of each of Cu(II), Cd(II), Fe(III), and Sn(IV) from their aqueous solutions decreased upon reuse of the biomass. Introducing mixed ethanol/water (50% v/v) metal ion solutions in batch systems enhanced the metal uptake of the exhausted biomass by 90% for iron, 40% for tin and only 14% for cadmium. In the column system, 20% v/v ethanol/water proved to be superior to acetone/water and isopropanol/water metal solutions in enhancing metal uptake. This increase in uptake offers a new method for regeneration of the algal capacity to remove metal ions from their solutions. Mossbauer results of iron and tin loaded algae from aqueous and mixed ethanol water solutions exhibited the characteristic doublet for (FeCl4-) at 0.350-0.565 mms(-1) respectively and the major doublet for inorganic Sn(IV) moieties at -0.217 to -0.365 mms(-1) respectively, excluding the possibility of microprecipitation of iron and tin, which is expected at such high concentrations of metals in the alga.     

Organ targeted prenatal gene therapy—how far are we?

Prenatal gene therapy aims to deliver genes to cells and tissues early in prenatal life, allowing correction of a genetic defect, before long-term tissue damage has occurred. In contrast to postnatal gene therapy, prenatal application can target genes to a large population of dividing stem cells, and the smaller fetal size allows a higher vector-to-target cell ratio to be achieved. Early-gestation delivery may allow the development of immune tolerance to the transgenic protein which would facilitate postnatal repeat vector administration if needed. Targeting particular organs will depend on manipulating the vector to achieve selective tropism and on choosing the most appropriate gestational age and injection method for fetal delivery. Intra-amniotic injection reaches the skin, and other organs that are bathed in the fluid however since gene transfer to the lung and gut is usually poor more direct injection methods will be needed. Delivery to the liver and blood can be achieved by systemic delivery via the umbilical vein or peritoneal cavity. Gene transfer to the central nervous system in the fetus is difficult but newer vectors are available that transduce neuronal tissue even after systemic delivery. Copyright © 2011 John Wiley & Sons, Ltd.     

Characterization of cytotoxicity of airborne particulates from urban areas of Lahore

A number of species (organic and inorganic) in airborne particulates cause the toxicity to living being. The potential of in vitro test methods were explored for toxicity assessment of trace toxic elements (inorganic species) present in ambient air on human being (lungs). A year long sampling of airborne particles (PM_2.5) was carried (April 2008 to March 2009) in Lahore, Pakistan. A total of thirty nine samples were collected on 47 mm Zefluor Teflon filter membranes and each was analysed to characterize for the elements: Sb, As, Be, Cd, Cr, Co, Pb, Mn, Hg using ICP-MS in water extract and total acid digestate. The samples cytotoxicity was also established using lung derived cells and MTS colorimetric assays. This generated dose response curves and IC₅₀ values for the elemental mixtures identified on the Teflon filter membrane. The results indicated that even at low concentrations airborne elemental mixtures displayed an additive toxic effect.     

Minimizing predation risk in a landscape of multiple predators: effects on the spatial distribution of African ungulates

Studies that focus on single predator-prey interactions can be inadequate for understanding antipredator responses in multi-predator systems. Yet there is still a general lack of information about the strategies of prey to minimize predation risk from multiple predators at the landscape level. Here we examined the distribution of seven African ungulate species in the fenced Karongwe Game Reserve (KGR), South Africa, as a function of predation risk from all large carnivore species (lion, leopard, cheetah, African wild dog, and spotted hyena). Using observed kill data, we generated ungulate-specific predictions of relative predation risk and of riskiness of habitats. To determine how ungulates minimize predation risk at the landscape level, we explicitly tested five hypotheses consisting of strategies that reduce the probability of encountering predators, and the probability of being killed. All ungulate species avoided risky habitats, and most selected safer habitats, thus reducing their probability of being killed. To reduce the probability of encountering predators, most of the smaller prey species (impala, warthog, waterbuck, kudu) avoided the space use of all predators, while the larger species (wildebeest, zebra, giraffe) only avoided areas where lion and leopard space use were high. The strength of avoidance for the space use of predators generally did not correspond to the relative predation threat from those predators. Instead, ungulates used a simpler behavioral rule of avoiding the activity areas of sit-and-pursue predators (lion and leopard), but not those of cursorial predators (cheetah and African wild dog). In general, selection and avoidance of habitats was stronger than avoidance of the predator activity areas. We expect similar decision rules to drive the distribution pattern of ungulates in other African savannas and in other multi-predator systems, especially where predators differ in their hunting modes.     

Effect of teeth amalgam on mercury levels in the colostrums human milk in Lenjan

Human milk is usually the only source of food for infants during the first 4 to 5 months of their life. Maternal environmental mercury exposure is directly related to fish consumption or amalgam filling. In this research, 38 human milk samples were collected from mothers of Lenjan area who were not occupationally exposed with mercury. Mercury concentration in human milk was determined by AMA254 Mercury Analyzer. A level of mercury was examined in relation to somatometric, demographic and dental amalgam parameters. Obtained results showed that only dental amalgam significantly increased the mercury level in human milk (p < 0.001). The mean mercury concentrations in milk of mothers without teeth fillings (n = 13), with one to three teeth fillings (n = 10), and four to eight teeth fillings (n = 15) were 2.87, 5.47, and 13.33 μg/l, respectively. The result of this study also showed a positive correlation of mercury milk levels with the number of teeth fillings of the mother (p < 0.05, r = 0.755). The estimated weekly intake of mercury of a breastfed infant in this study was, in some cases, higher than provisional tolerance weekly intake recommended by FAO/WHO, which pose a threat to their health.     

Improved Titrilog Sensitivity

ABSTRACT

A method was developed to reproducibly measure environmental tobacco smoke (ETS) components generated by different cigarettes. Measurements were carried out in an unventilated, controlled environment chamber. True ETS (the aged and diluted combination of exhaled mainstream plus sidestream smoke) was generated by human smokers. To reliably quantitate components normally present at trace levels, the comparisons were carried out at elevated ETS concentrations—greater than 40 times those typically encountered in “real-world” settings.

The method was applied to four commercially available cigarettes and a cigarette prototype that primarily heats tobacco. Forty-three properties and components of the gas and particulate phases of ETS generated by the different cigarettes were measured. Good precision of measurement was obtained both within and between tests. Statistically significant differences in the concentration of ETS components were observed among the different commercial cigarettes and between the commercial and prototype cigarettes. Most ETS components from the prototype cigarette were reduced by >90% when compared to the commercial cigarettes. The method was used to determine the effect of cigarette design changes on the generation of ETS.     

Current Technology for Continuous Monitoring of Particulate Emissions

Particulate matter is characterized by its physical and chemical properties. Federal and state emission standards identify two important physical properties, opacity (visible emissions) and particulate mass concentration. In addition, particle size and particle composition are characteristics that play a significant role in the assessment of health effects, visibility, and control strategy. Systems to monitor these particle characteristics are in various stages of development. Opacity monitors have the longest history of commercial availability and of applicability to various source emissions. Particulate mass monitors have a short history as commercially available systems and are under evaluation in various source applications. Particle size monitors are mainly in the advanced prototype development stage undergoing evaluation. Particle composition monitors are in the early stages of development as research prototypes. Real time size monitoring systems will eventually be wedded to real time particle composition analyzers to give a monitoring system for particle size distributions of chemical constituents.     

Dielectric and Material Properties of Poly (Vinyl Alcohol): Based Modified Red Mud Polymer Nanocomposites

Red mud emerges as the major waste material during production of alumina from bauxite by the Bayer??s process. Based on economics as well as environmental related issues, enormous efforts have been directed worldwide towards red mud management issues i.e. of utilization, storage and disposal. The present research work has been undertaken with an objective to explore the use of red mud as a reinforcing material in the polymer matrix as a low cost option. The silicate layered red mud was organophilized by aniline formaldehyde and to know the effect of various filler loading on the material properties of PVA-organophilized red mud composites, prepared by a conventional solvent casting technique and comparison of the same with that of the virgin poly (vinyl alcohol) (PVA), various characterizations was done. The modified red mud was typically characterized by X-ray diffraction. The X-ray diffraction pattern of the composite materials was also studied. The morphological image of the composite materials was studied by scanning electron microscopy (SEM). Transmission electron microscopy (TEM) was used to characterize the dispersion of the red mud within the composite materials. The surface topography of the composite materials was studied by Atomic Force Microscopy (AFM). The dielectric properties of composite materials were investigated in wide frequency ranges from 1?MHz to 1?GHz.