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Purpose: Major aim of the work was to formulate 2-parameters models of the cavitation erosion process and to bring about the particular methods for prediction of its performance with due calculation formulas. Design/methodology/approach: Phenomenological model of the erosion supplemented with functional relationships between calculation parameters and the strength parameters stand for the foundations of the method. Having assumed the probabilistic nature of the process and fatigue regime of the material destruction, the volume loss in time has been determined as proportional to the integral of the appropriate probability function. Correlations between parameters have been derived by adjusting the computed erosion curves to the experimental ones for the vast diversity of the cases. Findings: Two different formulas for the volume loss of the material in time under cavitation loading have been derived. Research limitations/implications: Results obtained from both the International Cavitation Erosion Test program as well as the own experiments carried out at the rotating disk set-up supplied necessary experimental data. Preliminary verification of the method soundness was completed. Assumption on the independence of the calculation parameters on the loading conditions have been taken. The approach is valid provided the defined relationships are also independent on the type and amplitude of the loading. Practical implications: Achieving the objectives is expected to result in developing a technique for assessment of the material damage under cavitation loadings. Numerical implementation of the model completed with the derived functional relationships stand for a tool, enabling a prospective user to predict the material performance under defined cavitation loading. Originality/value: New formulas for calculating the efficiency of cavitation erosion, inferred from the models of high physical clarity are the original contribution to the methodology and techniques concerned. [ABSTRACT FROM AUTHOR]

Purpose: Propagation‐based phase‐contrast computed tomography (PB‐CT) is a method for three‐dimensional x‐ray imaging that utilizes refraction, as well as absorption, of x rays in the tissues to increase the signal‐to‐noise ratio (SNR) in the resultant images, in comparison with equivalent conventional absorption‐only x‐ray tomography (CT). Importantly, the higher SNR is achieved without sacrificing spatial resolution or increasing the radiation dose delivered to the imaged tissues. The present work has been carried out in the context of the current development of a breast CT imaging facility at the Australian Synchrotron. Methods: Seven unfixed complete mastectomy samples with and without breast cancer lesions have been imaged using absorption‐only CT and PB‐CT techniques under controlled experimental conditions. The radiation doses delivered to the mastectomy samples during the scans were comparable to those approved for mammographic screening. Physical characteristics of the reconstructed images, such as spatial resolution and SNR, have been measured and compared with the results of the radiological quality assessment of the complete absorption CT and PB‐CT image stacks. Results: Despite the presence of some image artefacts, the PB‐CT images have outperformed comparable absorption CT images collected at the same radiation dose, in terms of both the measured objective image characteristics and the radiological image scores. The outcomes of these experiments are shown to be consistent with predictions of the theory of PB‐CT imaging and previous reported experimental studies of this imaging modality. Conclusions: The results presented in this paper demonstrate that PB‐CT holds a high potential for improving on the quality and diagnostic value of images obtained using existing medical x‐ray technologies, such as mammography and digital breast tomosynthesis (DBT). If implemented at suitable synchrotron imaging facilities, PB‐CT can be used to complement existing imaging modalities, leading to more accurate breast cancer diagnosis. [ABSTRACT FROM AUTHOR]

In this study, we aimed to investigate disulfide/thiol homeostasis in trichloroethylene (TCE) exposure. The study was carried out in 30 nonsmoker TCE-exposed workers with a variety of occupations. Additionally, 30 healthy nonsmoker volunteers were recruited as the control group. TCE exposure was determined by measuring urinary trichloroacetic acid (TCA) concentration. Median urinary TCA levels of exposed workers (20.5 mg/L) were significantly higher than control subjects (5 mg/L). Thiol and disulfide concentrations were determined using a novel automated method. Disulfide/thiol ratio was significantly higher in the exposed group (p < 0.001). Thiol/disulfide homeostasis was found to be disturbed in TCE-exposed workers. We predict that in TCE-exposed workers this disturbance can be a therapeutic target, and the efficiency of the treatment can easily be monitored by the novel method we used. [ABSTRACT FROM AUTHOR]

The purpose of the work presented in this paper was to adapt the Multiple Sorption Model (MSM), originally developed for hard coals, to study sorption in lignites. It also includes an analysis of the sorption process of small molecule compounds in lignites. Measurements were made of the sorption isotherms of carbon dioxide in two samples of lignite from Polish collieries at different temperatures (298, 313 and 323 K) and in the pressure range up to 5 MPa. Subsequently, simulations of the isotherms for selected carbon dioxide-lignite systems were performed using the MSM. They were evaluated using the empirical isotherms until agreement of the isotherms was attained and the parameters of the sorption system reached reasonable values. Surprisingly, a low contribution of absorption was found in the overall sorption process probably as an effect of the high porosity of the sample and the presence of a large number of high-energy sites on the coal surface. Sorbate molecules occupied these high-energy sites on the surface and did not migrate to the absorption subsystem. [ABSTRACT FROM AUTHOR]

The decline of the European eel ( Anguilla anguilla) stock has led the European Commission to enforce a regulation (Council Regulation N° 1100/2007), in which each member state was required to establish an eel management plan. Various measures in the French plan aim at restoring river connectivity by mitigating the impact of obstacles on the colonization of continental water by eels. Consequently, many obstacles are going to be equipped with elver ladder in the near future. In this context, a method to assess the passability of an obstacle seems essential. In this study, we developed a tag-recapture method, appropriate to glass eels and elvers, and an associated multi-state mark-recapture model (i) to assess the passability of a ladder and (ii) to quantify the effect of various environmental factors on this passability. An application to a specific obstacle is applied as an illustrative example that demonstrates the relevance of the assessment method, and how the results can be used to propose technical solution to improve the efficiency of the ladder. Nine tag-recapture campaigns were carried on this obstacle, and about 4400 young eels were tagged. The model demonstrates that the efficiency of the ladder was rather low, especially during low river flow periods, mainly because of accessibility problems. The model also demonstrates the major influence of the river flow on the probability for an eel to pass the ladder; consequently, managing river flow during the migration period can be a relevant measure to improve river connectivity and facilitate colonization of the watershed. Copyright © 2014 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

A dynamic population model was developed to study the impact of biotic and abiotic environmental factors on changes in trout populations. The model is based on the Leslie Matrix and simulates population change by age class in terms of biological parameters (i.e. fish survival, fertility, growth rates), which are dependent on environmental conditions. Changes in physical habitat, expressed as Weighted Usable Area, cause displacement of fish and increased mortality. Calculations were made at 1-month intervals to account for the effect of climatic variations on the population. The model was used to analyze the dynamics of two trout populations, quite different in terms of their biological characteristics: one in Lower Normandy in the Oir watershed and the other in the Pyrenees Mountains in the Neste d'Oueil watershed. Application of the model to those populations revealed two types of stabilizing mechanisms. The first was a capacity for population restoration, which is well-represented by the model through the phenomenon of density-dependent mortality in the first months of life. The second was adjustment of the adult population to the carrying capacity of the environment. The two applications demonstrate the utility of this type of model for understanding and simulating the dynamics of different cohorts of a population. Coupling habitat models and dynamic population models facilitates the identification of key periods during which carrying capacity-related to the hydrology-becomes a limiting factor for fish. This brings new perspectives to water management and may facilitate analysis of instream flow requirements related to water development projects, such as hydropower plants. Copyright © 2001 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

The variability of mesohabitat used by populations of brown trout Salmo trutta was studied in seven rivers of the central Pyrenees, France. Physical habitat preferences of individuals, intraspecific competition, season, and diversity of adjacent channel unit segments explained the trout density variation among different types of mesohabitat. Total trout density, size-class densities, and redd densities differed significantly among mesohabitats and 18 subgroups of a hierarchical classification. The total density followed a gradient from deep channel morphodynamic units to shallow rapids including step channel, glides, riffles, and cascades. The different size-classes of trout expressed a strong spatial segregation between fry and adult stages. Fry were more often found in riffles and glides, whereas adults concentrated in deep habitats. During the reproduction period, the highest redd densities were observed in glides and riffles. The density of trout in deep mesohabitat increased in relation to the diversity of mesohabitat type and the percentage of riffles in the adjacent segment. These results clearly showed the importance of the diversity of hydrodynamic conditions for the life cycle of brown trout in mountain streams. [ABSTRACT FROM AUTHOR]

In this study we demonstrate the first direct comparison between synchrotron x-ray propagation-based CT (PB-CT) and cone-beam breast-CT (CB-CT) on human mastectomy specimens (N = 12) including different benign and malignant lesions. The image quality and diagnostic power of the obtained data sets were compared and judged by two independent expert radiologists. Two cases are presented in detail in this paper including a comparison with the corresponding histological evaluation. Results indicate that with PB-CT it is possible to increase the level of contrast-to-noise ratio (CNR) keeping the same level of dose used for the CB-CT or achieve the same level of CNR reached by CB-CT at a lower level of dose. In other words, PB-CT can achieve a higher diagnostic potential compared to the commercial breast-CT system while also delivering a considerably lower mean glandular dose. Therefore, we believe that PB-CT technique, if translated to a clinical setting, could have a significant impact in improving breast cancer diagnosis. [ABSTRACT FROM AUTHOR]