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961.
962.
We employed our inhalation methodology to examine whether biomarkers of inflammation and oxidative stress would be produced in mice following inhalation of aerosols containing carbonaceous particles or the vapor of pesticides prevalent during the first Gulf War. Exposure to two putative Gulf War Illness toxins, fine airborne particles and the pesticide malathion, increased biomarkers of inflammation and oxidative stress in Friend virus B (FVB) female mice. Mice inhaling particles 24 h before had increased lung lavage and plasma Leukotriene B4 (LTB4) (a biomarker of inflammation) and PGF (a biomarker of oxidative stress) levels, lung lavage protein and lung lavage lactic dehydrogenase (LDH) levels. These changes were a function of particle density and exposure time. Compared to particle inhalation, mice inhaling malathion 24 h before had small increase in plasma LTB4 and PGF levels but no increase in lung lavage LTB4, lung lavage protein, lung lavage LDH, and lung lavage alveolar macrophage (AM) levels compared to unexposed control mice. AM from particle-exposed mice contained phagocytosed particles, while AM from malathion-exposed mice showed no abnormalities. Our results indicate that inhaling particles or malathion can alter inflammatory and oxidative biomarkers in mice and raise the possibility that these toxins may have altered inflammation and oxidative stress biomarkers in Gulf War-exposed individuals.  相似文献   
963.
Aquatic macrophytes’ decomposition is a source of recalcitrant carbon in the long term contributing to humic substances (HS) formation. Understanding the influence of plant detritus quality and oxygen availability over molecular changes of these compounds provides ecological information related to their cycling. This study described the molecular variation of dissolved HS from Eichhornia azurea, Egeria najas, Oxycaryum cubense and Salvinia molesta decomposition under aerobic and anaerobic conditions. The aquatic HS formed from the four aquatic macrophytes showed similar features (e.g. molecular weight and aromaticity). This fact indicates little influence of the detritus quality or availability of oxygen on the fulvic acids (FA) and humic acid characteristics. Under aerobic condition a decrease in the polysaccharides content in FA occurred. HS from E. najas were related to less-recalcitrant features, while HS from S. molesta were related to recalcitrant.  相似文献   
964.

The present study determines the influence of three ionic liquids (ILs) containing cations with diversified structure on the growth and development of spring barley seedlings and common radish leaves. Increasing amounts of 1-butyl-1-methylpyrrolidinium hexafluorophosphate [Pyrrol][PF6], 1-butyl-1-methylpiperidinium hexafluorophosphate [Piper][PF6], and 1-butyl-4-methylpyridinium hexafluorophosphate [Pyrid][PF6] were added to the soil on which both plants were cultivated. The results of this studies showed that the applied ILs were highly toxic for plants, demonstrated by the inhibition of length of plant shoots and roots, decrease of fresh mass, and increase of dry weight content. Common radish turned out to be the plant with higher resistance to the used ILs. The differences in the cation structure did not influence phytotoxity of ILs for spring barley. Furthermore, all ILs led to a decrease of photosynthetic pigments, which was directly followed by decreased primary production in plants. Oxidative stress in plants occurred due to the presence of ILs in the soil, which was demonstrated by the increase of malondialdehyde (MDA) content, changes in the H2O2 level, and antioxidant enzymes such as superoxide dismutase (SOD), catalase (CAT), and peroxidase (POD). The changes in the chlorophyll contents and the increase of POD activity turned out to be the most significant oxidative stress biomarkers in spring barley and common radish. Both spring barley and radish exposed to ILs accumulated a large amount of fluoride ion.

  相似文献   
965.
Conserving irreplaceable, archived serum samples may sometimes conflict with the objective of minimizing measurement error due to laboratory effects. We sought to determine whether we could successfully combine assay results for DDT-related compounds and polychlorinated biphenyls (PCBs) in serum from the same birth cohort obtained from different laboratories over time. Using the Child Health and Development Studies (CHDS) serum archive, we compared variability for assays of a quality control pool to variability for assays of subject serum. The quality control pool was created from native archived serum samples that were pooled, then aliquoted, blinded and inserted pair-wise into assay batches along with the subject serum for 5 studies using CHDS samples conducted over a 13year period by three different laboratories. We found that the variability between laboratory and over time within laboratory was small relative to inter-individual variability for p,p'-DDT (1,1,1-trichloro-2,2-bis(p-chlorophenyl)ethane), p,p'-DDE (1,1'-dichloro-2,2'-bis(p-chlorophenyl)ethylene) and o,p'-DDT (1,1,1-trichloro-2-(p-chlorophenyl)-2-(o-chlorophenyl)-ethane). Results were also consistent for most PCB congeners which were detectable in 85% or more of samples. Our results suggest that it is possible to combine assays for DDT and PCB congeners measured at positive levels as they are accumulated for cohort subjects without risking meaningful misclassification due to variation stemming from laboratory or time period. This has significant implications for future study costs, conservation of irreplaceable archived samples and for leveraging past investments for future research. For PCB congeners with very low levels, findings caution against pooling of assays without further exploration.  相似文献   
966.
967.
This paper presents an evaluation of the consistency of an urban state-of-the-art hydrocarbon (HC) emission inventory. The evaluation was conducted through the comparison of this inventory with hourly HC measurements during two summer months in the centre of Marseille, on the Mediterranean French coast. Factors of under or overestimation could be calculated for each compound on the basis of a systematic HC to HC ratio analysis. These results, associated with a deep analysis of the speciation profiles, show that most of the common and highly concentrated hydrocarbons (such as butanes) are too much predominant in the emission speciation, while the heavy and less common species (branched alkanes, substituted aromatics) are under-represented in the inventory. The urban diffuse sources appear here as one critical point of the inventories. The disagreements were shown to have a strong incidence on the representation of the air mass reactivity. In a last step, the identified uncertainties in emissions were implemented in an air-quality model for sensitivity studies. It was shown that the observed biases in the inventory could affect the regional ozone production, with a probable impact on ozone peaks of 2–10 ppbv over the area.  相似文献   
968.
Methods for estimating the proportion of fish that exhibit gross pathological disorders and for estimating the variance of these estimates are defined. The methods are for the situation in which a probability-based sampling design is used to collect fish for examination, but geographic locations (rather than individual fish) are assigned probabilities of being selected for sampling. To illustrate the use of the methods, they are applied to data collected during the 1992 EMAP- Estuaries sampling program in the Louisianian Province (i.e., the Gulf of Mexico). Separate estimates of the proportion of fish with gross pathological disorders are computed for demersal species, commercial species, pelagic species, and all species as one group. In addition, a test for trend in the proportion of fish that exhibit gross pathological disorders is defined, and analyses of the power of the test are presented. The power analyses are based on a general underlying model of the random distribution patterns of fish and the random process of catching fish. The power analyses also take into account the features of the sampling designs used for collecting fish. Component parameter estimates were computed using data from the 1992 EMAP-Estuaries sampling program in the Louisianian Province. Results from these analyses suggest that the EMAP-Estuaries sampling designs are capable of detecting a 0.15% change per year in the proportion of fish (all species groups combined) with gross pathological disorders in estuaries of the Louisianian Province over a 12-year period with a power of at least 80%. © Rapid Science 1998  相似文献   
969.
Abstract: Traditionally, marine resources have been managed such that controls on new developments are implemented only when harmful effects on other environmental or economic interests can be demonstrated. This approach poses particular problems for the conservation of coastal cetaceans because potential threats to their populations are diverse and likely to interact, individual threats may result from multiple sources, and the problems inherent in studying cetaceans result in considerable scientific uncertainty and low statistical power to detect any effects. Consequently, many countries are adopting integrated coastal management programs and precautionary management principles. In practice, however, issues continue to be dealt with within traditional frameworks that require demonstration of harm. Because cetaceans are long-lived, they demand long-term studies, and populations could decline to dangerously low levels before management action is taken. We illustrate these problems using a case study from the Moray Firth, Scotland. This inshore area will soon be designated and managed as a "special area of conservation" to protect bottlenose dolphins (   Tursiops truncatus ) under the European Community's Habitats Directive. The population is small and isolated, and it faces a wide range of potential threats, but there remains considerable uncertainty over the magnitude of each threat. We combined power analysis and population viability analysis to explore the relative consequences of adopting either traditional or precautionary approaches to management. In this case, our results reaffirm the need for precautionary management. More generally, we illustrate how this approach can be used to provide a more scientific basis for determining the level of precaution required to address particular management issues in this and other marine systems.  相似文献   
970.
Capacity for environmental protection is important in developed and transitional countries, but the latter sometimes present a paradox where capacity has been created at the same time as public pressure and awareness has diminished. Slovakia presents a particular paradox, as its new democratic institutions have proved especially fragile. This paper adopts a framework developed by Janicke and Weidner in crossnational studies which implies that the use made of environmental capacity is a function of institutional, informational and structural conditions. By analysing the key features of the Slovakian environmental policy process in the context of these conditions, the paper confirms the utility of the model, and points to the prospects for future policy implementation.  相似文献   
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