Combined exposure to cyanobacterial biomass, lead and the Newcastle virus enhances avian toxicity

Under environmental conditions, wild birds can be exposed to multiple stressors including natural toxins, anthropogenic pollutants and infectious agents at the same time.This experimental study was successful in testing the hypothesis that adverse effects of cyanotoxins, heavy metals and a non-pathogenic immunological challenge combine to enhance avian toxicity. Mortality occurred in combined exposures to naturally occurring cyanobacterial biomass and lead shots, lead shots and Newcastle vaccination as well as in single lead shot exposure. Mostly acute effects around day 10 were observed. On day 30 of exposure, there were no differences in the liver accumulation of lead in single and combined exposure groups. Interestingly, liver microcystin levels were elevated in birds co-exposed to cyanobacterial biomass together with lead or lead and the Newcastle virus. Significant differences in body weights between all Pb-exposed and Pb-non-exposed birds were found on days 10 and 20. Single exposure to cyanobacterial biomass resulted in hepatic vacuolar dystrophy, whereas co-exposure with lead led to more severe granular dystrophy. Haematological changes were associated with lead exposure, in particular. Biochemical analysis revealed a decrease in glucose and an increase in lactate dehydrogenase in single and combined cyanobacterial and lead exposures, which also showed a decreased antibody response to vaccination.The combined exposure of experimental birds to sub-lethal doses of individual stressors is ecologically realistic. It brings together new pieces of knowledge on avian health. In light of this study, investigators of wild bird die-offs should be circumspect when evaluating findings of low concentrations of contaminants that would not result in mortality on a separate basis. As such it has implications for wildlife biologists, veterinarians and conservationists of avian biodiversity.     

Mineralogy of air-pollution-control residues from a secondary lead smelter: environmental implications

The mineralogy and solubility of air-pollution-control (APC) residues from a secondary lead (Pb) smelter have been studied on samples from the Príbram smelter, Czech Republic, recycling car batteries, with the emphasis on their potential environmental effect. The presence of dominant anglesite (PbSO4) and laurionite (Pb(OH)Cl) was observed in a sintered residue from after-burning chambers (800-1000 degrees C). In contrast, low-temperature Pb-bearing phases, such as KCl x 2PbCl2 and caracolite (Na3Pb2(SO4)3Cl), were detected in the major APC residue from bag-type fabric filters. Metallic elements, zinc (Zn), cadmium (Cd), and tin (Sn) were found homogeneously distributed within this residue. The formation of anglesite, cotunnite (PbCl2), (Zn,Cd)2SnO4, and (Sb,As)2O3 was observed during the sintering of this APC residue at 500 degrees C in a rotary furnace. The 168 h leaching test on filter residue, representing the fraction that may escape the flue gas treatment system, indicated rapid release of Pb and other contaminants. Caracolite and KCl x 2PbCl2 are significantly dissolved, and anglesite and cotunnite form the alteration products, as was confirmed by mineralogical analysis and PHREEQC-2 modeling. The observed Pb-bearing chlorides have significantly higher solubility than anglesite and, following emission from the smelter stack, can readily dissolve, transferring Pb into the environmental milieu (soils, water, inhabited areas).     

Reactive phenylbenzimidazole UV absorbers and their application to cellulose textiles

New types of reactive UV absorbers for applications to cellulose textiles have been prepared. These substances are condensation products of sulfobenzimidazolaniline, cyanuric chloride, and aminophenyl‐(2‐sulfethoxy)‐sulfone. They were applied to bleached, unbleached, as well as dyed cellulose textiles with the aim to increase the protection effect of these textiles against UV radiation. All the tested textiles showed a marked increase in the UV protection factor (UPF). The effects of the UV absorbers tested neither interfere with the function of fluorescent brighteners (FBs) nor affect the hue of the used dyestuffs. They exhibit synergistic effect in the protection effectiveness against UV radiation: the UV absorbers used together with dyestuffs and FBs have a higher UPF factor than is the sum of UPF contributions of the individual components. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Influence of Precipitates Size and Distribution on Room Temperature Mechanical Properties and Accelerated Creep of X20CrMoV121

The effect of microstructure on creep resistance of the low carbon chromium steel X20CrMoV121 after 100‐hours of static‐load test at a temperature of 580 °C and constant stress of 170 MPa was investigated. The specimens for the experiments were extracted from steam pipes of a steam power plant and heat treated. The effect of isothermal annealing on the microstructure and hardness as well as the kinetics of the precipitation of the carbide particles were determined.     

Spaceborne Radar Subsurface Imaging in Hyperarid Regions

Imaging data acquired with the Shuttle Imaging Radar (SIR-A) over the hyperarid region of Egypt/Sudan clearly show surface penetration through the sand cover. Even though absorption does occur in the sand layer, surface refraction leads to a steeper incidence angle at the sand/bedrock interface resulting in a stronger backscatter. A simple backscatter model shows that for a low-loss thin sand layer the presence of the covering layer enhances the capability to image the subsurface interface, particularly at large incidence angles and HH polarization.     

Chiroptical Properties of Phorbol-12, 13, 20-triacetate and Some Other Phorbol Derivatives

The CD spectra of phorbol and of some of its derivatives, such as its 12, 13, 20-triacetate 1, show at least four bands. Three of them (called I, III, and IV) correspond to the R-, K-, and (perhaps) second n → π*-transition, respectively, of the enone system; the fourth band around 260 nm (band II) is of π → π*-origin and could be ascribed to an interaction of the lone pair of electrons on the oxygen atom at C(4) with the C=C-C=O system. The signs of the R-band as well as the K-band Cotton effects are very sensitive to chemical modifications around the chromophoric system in the cyclopentenones investigated. The absolute configuration of phorbol may be derived from the CD spectra of some of its derivatives, and, in particular, from the application of the “dibenzoate rule” to 12, 13-di-O-benzoyl phorbol-20-acetate (4).     

Dynamic tear tests of carbon weldable steels

For determining the crack arrest temperature of structural weldable steels of mass production, it is convenient to use the dynamic tear test because of its simple and low cost application using drop weight testers or pendulum testing machines. The dependence of the dynamic tear energy on temperature can in fact represent the curve of the crack arrest temperatures. The energy/temperature results have to be transformed into the nominal stress vs. temperature coordinates to permit a better review and simpler application. This work describes two methods of making such transformations and shows some results acquired with carbon weldable structural steels.