Lipid peroxidation in the presence of iron oxides

Exposure to iron oxides dusts may lead to lung cancers among exposed population. To evaluate the involvement of iron‐containing particles in lipid peroxidation by production of reactive oxygen species, hematite, magnetite (iron oxides), and crocidolite (asbestos compound) were tested. The peroxidation was followed by the evaluation of some degradation products of lino‐lenic acid. In a buffered medium, magnetite is higher active than hematite. The addition of an iron chelator (EDTA) or of a reducing agent (ascorbate) in this medium enhances the activity of hematite and magnetite, and the combination of both EDTA and ascorbate increases their activity. Crocidolite is the most active whatever the medium. The appearance of the EDTA‐iron‐oxygen complexes related to the reactivity of these oxides is postulated. These results suggest that the oxidizing activity triggered by hematite and magnetite, in a medium containing an iron chelator and a reducing agent, may lead to damages in biological medium.     

The management of severe malnutrition in Burundi: an NGO's perspective of the practical constraints to effective emergency and medium-term programmes

The NGO, Action contre la Faim (ACF), has been operating in Burundi since 1994, where the situation has dramatically hampered humanitarian programmes. These include poor security resulting in an inability to maintain 24-hour care for the severely malnourished and poor access to the beneficiaries, all within a politically and economically unstable context. However, ACF has been able to capitalise on lessons learnt and reflect on ways to move forward, which have included the improvement of their capacities in the treatment of severe malnutrition and the integration within broader disciplines and national structures. The protocols for the treatment of severe malnutrition currently used in Burundi have been developed as a result of the research of ACF over the past five years. Other aspects of the nutrition programme remain to be further developed. These include, for example, an improved capacity to care for severely malnourished adolescents and adults; and also a better knowledge of the beneficiaries to allow for stronger links between the provision of treatment and support for their longer-term food security.     

Degradation of CL-20 by white-rot fungi

In previous studies, we found that the emerging energetic chemical, CL-20 (C6H6N12O12, 2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane), can be degraded following its initial denitration using both aerobic and anaerobic bacteria. The C and N mass balances were not determined due to the absence of labeled starting compounds. The present study describes the degradation of the emerging contaminant by Phanerochaete chrysosporium using ring-labeled [15N]-CL-20 and [14C]-CL-20. Ligninolytic cultures degraded CL-20 with the release of nitrous oxide (N2O) in amounts corresponding to 45% of the nitrogen content of CL-20. When ring-labeled [15N]-CL-20 was used, both 14N14NO and 15N14NO were observed, likely produced from -NO2 and N-NO2, respectively. The incubation of uniformly labeled [14C]-CL-20 with fungi led to the production of 14CO2 (> 80%). Another ligninolytic fungus, Irpex lacteus, was also able to degrade CL-20, but as for P. chrysosporium, no early intermediates were observed. When CL-20 was incubated with manganese peroxidase (MnP), we detected an intermediate with a [M-H]- mass ion at 345 Da (or 351 and 349 Da when using ring-labeled and nitro-labeled [15N]-CL-20, respectively) matching a molecular formula of C6H6N10O8. The intermediate was thus tentatively identified as a doubly denitrated CL-20 product. The concomitant release of nitrite ions (NO2-) with CL-20 degradation by MnP also supported the occurrence of an initial denitration prior to cleavage and decomposition.     

An architectural model of spring wheat: Evaluation of the effects of population density and shading on model parameterization and performance

ADELwheat is an architectural model that describes development of wheat in 3D. This paper analyzes the robustness of the parameterization of ADELwheat for spring wheat cultivars in relation to plant population density and shading. The model was evaluated using data from two spring wheat experiments with three plant population densities and two light regimes. Model validation was done at two levels of aggregation: (a) by comparing parameterization functions used as well as parameter values to the data (leaf and tiller appearance, leaf number, blade dimensions, sheath length, internode length) and (b) by comparing ground cover (GC) and leaf area index (LAI) of simulated virtual wheat plots with GC and LAI calculated from data. A sensitivity analysis was performed by modulating parameters defining leaf blade dimensions and leaf or tiller appearance rate.In contrast to population density, shading generally increased phyllochron and delayed tiller appearance. Both at the level of the organ and at the level of the canopy the model performed satisfactorily. Parameterization functions in the model that had been established previously applied to independent data for different conditions; GC and LAI were simulated adequately at three population densities. Sensitivity analysis revealed that calibration of phyllochron and blade area needs to be accurate to prevent disproportional deviations in output.The robustness of the model parameterization and the simulation performance confirmed that the model is a complete architectural model for aboveground development of spring wheat. It can be used in studies that require simulation of spring wheat structure, such as studies on plant–insect interaction, remote sensing, and light interception.     

Toxicological characterization of sediments from Baie des Anglais on the St. Lawrence Estuary.

The sediments of Baie des Anglais on the St. Lawrence Estuary have a history of environmental contamination, but no information exists relating to their toxicity. The purpose of the present study was to characterize three sites in and near Baie des Anglais, in terms of sediment toxicity and contaminants. Sites 1 and 2 within the Baie des Anglais are relatively close to local industry and municipal sewage discharge points, while Site 3 is outside the bay. Three microscale bioassays, Microtox, echinoderm fertilization and Toxi-ChromoPad, showed that sediments from Site 1 were the most toxic, followed by Site 2. Site 3 was non-toxic. While the solid phase Microtox test did indicate that Site 1 was most toxic, the absolute response was weak. Liver cytochrome P450 1A1 mRNA in American plaice (Hippoglossoides platessoides), captured at Site 1 in the bay was significantly induced compared to the P450 system of plaice captured at Sites 2 and 3. Hepatic metallothionein mRNA levels were not significantly different between plaice captured at all three sites. Sediment chemical analyses revealed a gradient in polycyclic aromatic hydrocarbons, polychlorinated biphenyls and dibenzofurans (PCDF) with the highest levels recorded at Site 1, about 10-fold less at Site 2 and 100-fold less at Site 3. Amongst the organochlorines the PCDF group were deemed the most important due to their prevalence and known toxicity. Heavy metal concentrations were low and representative of background levels for the St. Lawrence Estuary.     

Powered two-wheeler riders' risk of crashes associated with filtering on urban roads

Objective: The objective of this study is to estimate the crash risk per kilometer traveled by powered two-wheeler (PTW) riders filtering through traffic on urban roads.

Methods: Using the traffic injury crashes recorded by the police over a period of 3 years on 14 sections of urban roads in the city of Marseille, France, and a campaign of observations of PTWs, the crash risk per kilometer traveled by PTWs filtering was estimated and compared to the risk of PTWs that did not filter.

Results: The results show that the risk of PTW riders being involved in injury crashes while filtering is significantly higher than the risk for riders who do not filter. For the 14 sections studied, it is 3.94 times greater (95% confidence interval [CI], 2.63, 5.89). This excess risk occurred for all PTW categories. Furthermore, no space appears to be safer than the others for filtering. Riders filtering forward along the axis of the carriageway, along bus lanes, or between traffic lanes (lane-splitting) all have a crash risk greater than the risk of those who do not filter.

Conclusions: All measures limiting the practice of filtering by PTWs on urban roads would probably contribute to improving the safety of their users.