Polyethylene Oxidation in Total Hip Arthroplasty: Evolution and New Advances

Ultra-high molecular weight polyethylene (UHMWPE) remains the gold standard acetabular bearing material for hip arthroplasty. Its successful performance has shown consistent results and survivorship in total hip replacement (THR) above 85% after 15 years, with different patients, surgeons, or designs

Case study on the improved use of collective dose for nuclear and/or radiological emergencies

The improved use of collective dose following the 2007 ICRP recommendations is studied for nuclear and radiological emergency situations. To study the accumulation of low individual doses to the collective dose the collective dose is calculated as a function of the minimum individual dose for three cases including nuclear as well as radiological accidents. It is found that the use of collective dose in this way can have an added value in nuclear emergency preparedness and response in particular related to decisions on overall protective actions following an accident

Comparison of the Belgian interventions levels and the new ICRP recommendations for emergency exposures

The new recommendations on emergency exposure situations of the International Commission on Radiological Protection (ICRP) advise a reference level for the residual dose in a range of between 20 and 100 mSv effective dose (acute or per year). At the same time, the protection strategy should account for the simultaneous consideration of all the exposure pathways, as well as all of the protective actions. Similarly to other countries, the actual Belgian nuclear emergency plan is based on individual projected doses (thyroid committed dose and total effective doses) and independent protective actions that mainly focus on the early phase of an emergency situation. The two approaches are compared in this study on the basis of the projected and residual dose calculations obtained using JRODOS and the Belgian Noodplan models for different radiological or nuclear accidental scenarios. The comparison has been made by considering separately the early and the late phase contributions. The ingestion dose has been investigated from the predicted deposition values and compared to the single level of the ICRP 109 recommendations

Proposal for new best estimates of the soil-to-plant transfer factor of U, Th, Ra, Pb and Po

There is increasing interest in radiological assessment of discharges of naturally occurring radionuclides into the terrestrial environment. Such assessments require parameter values for the pathways considered in predictive models. An important pathway for human exposure is via ingestion of food crops and animal products. One of the key parameters in environmental assessment is therefore the soil-to-plant transfer factor to food and fodder crops. The objective of this study was to compile data, based on an extensive literature survey, concerning soil-to-plant transfer factors for uranium, thorium, radium, lead, and polonium. Transfer factor estimates were presented for major crop groups (Cereals, Leafy vegetables, Non-leafy vegetables, Root crops, Tubers, Fruits, Herbs, Pastures/grasses, Fodder), and also for some compartments within crop groups. Transfer factors were also calculated per soil group, as defined by their texture and organic matter content (Sand, Loam, Clay and Organic), and evaluation of transfer factors' dependency on specific soil characteristics was performed following regression analysis. The derived estimates were compared with estimates currently in use.Fil: Vandenhove, H.. Belgian Nuclear Research Centre; BélgicaFil: Olyslaegers, G.. Belgian Nuclear Research Centre; BélgicaFil: Sanzharovab, N.. Russian Institute of Agricultural Radiology and Agroecology; RusiaFil: Shubina, O.. Russian Institute of Agricultural Radiology and Agroecology; RusiaFil: Reed, E.. Center for Risk Analysis; Estados UnidosFil: Shang, Z.. Nuclear Safety Center of SEPA; ChinaFil: Velasco, Ricardo Hugo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto de Matemática Aplicada de San Luis "Prof. Ezio Marchi". Universidad Nacional de San Luis. Facultad de Ciencias Físico, Matemáticas y Naturales. Instituto de Matemática Aplicada de San Luis "Prof. Ezio Marchi"; Argentin

Morphological and physiological indicators of tolerance to atmospheric stress in two sensitive and two tolerant tea clones in South Africa

Tea (Camellia sinensis) clones (PC113 and SFS204) sensitive to very dry air and clones (PC114 and SFS150) that are, tolerant, were studied at two tea estates (Tshivhase and Grenshoek) in the Northern Province of the Republic of South Africa. Among the morphological leaf traits studied, stomatal density, pore diameter and pore depth were not linked consistently to stress tolerance. Cuticle thickness was not a good indicator of stress tolerance because genetic differences between clones were confounded by the clonal response of wax production to stress. In contrast, measured leaf conductance to water vapour transport was larger and leaf water potential was lower in sensitive clones, but only with more severe atmospheric stress (Grenshock). Also the ratio of the calculated maximum stomatal conductance in old and young leaves was higher in sensitive clones, suggesting that the loss of a larger fraction of the total stem flow by old leaves enhanced the stress experienced by the young leaves. However, this indicator was valid only under the more stressful microclimate of Grenshoek. The results indicate that even promising criteria for stress tolerance should be tested by exposure to stress during selection

A comparative radiological assessment of five European biosphere systems in the context of potential contamination of well water from the hypothetical disposal of radioactive waste.

In the framework of the BioMoSA project for the development of biosphere assessment models for radioactive waste disposal the Reference Biosphere Methodology developed in the IAEA programme BIOMASS was applied to five locations, situated in different European countries. Specific biosphere models were applied to assess the hypothetical contamination of a range of agricultural and environmental pathways and the dose to individuals, following contamination of well water. The results of these site-specific models developed by the different BioMoSA partners, and the individual normalised dose to the exposure groups were compared against each other. Ingestion of drinking water, fruit and vegetables were found to be among the most important pathways for almost all radionuclides. Stochastic calculations revealed that consumption habits, transfer factors, irrigation rates and distribution coefficients (Kd s) were the most important parameters that influence the end results. Variations in the confidence intervals were found to be higher for sorbing elements (e.g. 36Cl, 237Np, 99Tc, 238U, 129I) than for mobile elements (e.g. 226Ra, 79Se, 135Cs, 231Pa, 239Pu). The influence of daughter products, for which the distribution into the biosphere was calculated individually, was also shown to be important. This paper gives a brief overview of the deterministic and stochastic modelling results and the parameter sensitivity. A screening methodology was introduced to identify the most important pathways, simplify a generic biosphere tool and refine the existing models. © 2005 IOP Publishing Ltd