Endocrine alteration and other biochemical responses in juvenile turbot exposed to the Prestige fuel oil

Juvenile turbot (Scophthalmus maximus) were exposed to different concentrations of the Prestige fuel oil through the diet. The effects on hepatic biotransformation enzymes, namely, 7-ethoxyresorufin O-deethylase (EROD), catalase, and phase II activities - UDP-glucuronosyltransferases (UGT) and cytosolic sulfotransferases (SULT) -, were monitored after 42-day exposure. Additionally, potential alterations on the endocrine system of juvenile turbot were assessed by measuring circulating levels of testosterone and 17beta-estradiol in plasma, together with gonadal P450 aromatase activity and the glucuronidation of testosterone by liver microsomal fractions. Fluorescent aromatic compounds (FACs) in bile were determined as an indicator of exposure to polycyclic aromatic hydrocarbons (PAHs). EROD activity increased in a dose dependent manner, and a positive correlation between levels of FACs in bile and EROD activity was observed. A significant increase in UGT activity was observed in fish exposed to medium and high fuel doses, whereas SULT cytosolic activity was not responsive to exposure. Exposure to the Prestige fuel oil sharply reduced circulating levels of testosterone in plasma. The obtained results suggest the ability of the Prestige fuel oil to alter hepatic biotransformation enzymes and to disrupt endogenous hormone levels in juvenile turbot, with unknown consequences in terms of sexual differentiation and reproduction.     

Charge transport in disordered graphene-based low dimensional materials

Two-dimensional graphene, carbon nanotubes, and graphene nanoribbons represent a novel class of low dimensional materials that could serve as building blocks for future carbon-based nanoelectronics. Although these systems share a similar underlying electronic structure, whose exact details depend on confinement effects, crucial differences emerge when disorder comes into play. In this review, we consider the transport properties of these materials, with particular emphasis on the case of graphene nanoribbons. After summarizing the electronic and transport properties of defect-free systems, we focus on the effects of a model disorder potential (Anderson-type), and illustrate how transport properties are sensitive to the underlying symmetry. We provide analytical expressions for the elastic mean free path of carbon nanotubes and graphene nanoribbons, and discuss the onset of weak and strong localization regimes, which are genuinely dependent on the transport dimensionality. We also consider the effects of edge disorder and roughness for graphene nanoribbons in relation to their armchair or zigzag orientation. This article is published with open access at Springerlink.com     

Physical processes within a 2D granular layer during an impact

In this paper, the impact of a block on a coarse granular soil corresponding to rockfall events is investigated using the Discrete Element Method. Different impacting particle and medium characteristics (impact point, impacting particle size and shape, sample height, etc.) are considered. The numerical results first exhibit the physical phenomena involved in the interaction between the impacting particle and the granular medium. The impact process starts with the partial energy exchange from the impacting particle to the soil. This phase is followed by the propagation of a shockwave from the impact point and a wave reflection on the bottom wall of the sample. A second energy exchange from soil particles to the impacting particle can occur if the reflected wave reaches the soil surface before the end of the impact. Based on these investigations, the impacting particle bouncing occurrence diagram is defined for various impacting particle sizes, incident kinematic parameters and sample heights. The bouncing occurrence diagram brings out three impact regimes. For a small impacting particle, the impact is mainly determined by the first interaction between the impacting particle and the soil, whereas for an intermediate-sized impacting particle, the shockwave propagation through the sample is the leading phenomenon. For a large impacting particle, bouncing is associated with the formation of a compact layer below the impacting particle.     

Insight into silicate-glass corrosion mechanisms

The remarkable chemical durability of silicate glass makes it suitable for a wide range of applications. The slowdown of the aqueous glass corrosion kinetics that is frequently observed at long time is generally attributed to chemical affinity effects (saturation of the solution with respect to silica). Here, we demonstrate a new mechanism and highlight the impact of morphological transformations in the alteration layer on the leaching kinetics. A direct correlation between structure and reactivity is revealed by coupling the results of several structure-sensitive experiments with numerical simulations at mesoscopic scale. The sharp drop in the corrosion rate is shown to arise from densification of the outer layers of the alteration film, leading to pore closure. The presence of insoluble elements in the glass can inhibit the film restructuring responsible for this effect. This mechanism may be more broadly applicable to silicate minerals.     

A hybrid position/force control approach for identification of deformation models of skin and underlying tissues

In this paper, the focus is on the design of two biomechanical models representing the skin as well as the underlying tissues behavior and properties during a robotized harvesting process. The first model is quasi-static (i.e., without considering velocity) in the pressure direction of the tool: it is principally issued from the work of d'Aulignac et al. and some interesting properties are exhibited from it. The second model is new and takes into account velocity and lubrication in the motion direction of the tool. The goal of this study is to improve skin harvesting process in robotized reconstructive surgery, by automatically selecting the force applied on the donor area and tuning the gain factors of the control law prior to harvesting. It requires extracting relevant parameters such as skin thickness and stiffness, friction coefficient, etc. that characterize the biomechanical properties of the skin and underlying tissues of each patient and of different harvesting surfaces on a given patient (thigh, skull, buttocks, ...). Due to the surgical constraint, the in vivo procedure should be performed in the operating room before starting the operation with the robot itself thanks to a suitable hybrid position/force controller. In this paper, a survey about soft tissue modeling is presented. Mathematical models are discussed along with identification protocols, and two models are chosen that meet our requirements. Finally, experimental results are presented on foam and human skin.     

Sensitivity variation of doped Fricke gel irradiated with monochromatic synchrotron X rays between 33.5 and 80 keV

An experimental binary radiotherapy proposes the concomitant use of a high-Z compound and synchrotron X rays for enhancing radiation dose selectively in tumours by a photoelectric effect. This study aimed at measuring the resulting dose enhancement in irradiated material. A doped Fricke gel dosemeter model was manufactured with 10 mg ml(-1) of iodine (Telebrix) or barium (Micropaque). Samples were irradiated with a monochromatic synchrotron beam at 33.5, 50, 65 and 80 keV. The ensuing enhancement of the sensitivity of the dosemeter was derived from the nuclear magnetic resonance relaxation rates measured at different X-ray doses. Our results demonstrate (1) the preservation of a linear relationship between relaxation rates and X-ray doses for dosemeters doped with high-Z atoms and (2) a clear energy-dependent sensitivity enhancement for barium-doped Fricke gels. This enhancement was neither reproducible with iodinated compounds nor clearly related to the expected dose enhancement factor. However 1% barium sulphate in the gel could significantly improve the gel's response when it was irradiated by low-energy X rays.     

Building an infrastructure for scientific Grid computing: status and goals of the EGEE project

The state of computer and networking technology today makes the seamless sharing of computing resources on an international or even global scale conceivable. Scientific computing Grids that integrate large, geographically distributed computer clusters and data storage facilities are being developed in several major projects around the world. This article reviews the status of one of these projects, Enabling Grids for E-SciencE, describing the scientific opportunities that such a Grid can provide, while illustrating the scale and complexity of the challenge involved in establishing a scientific infrastructure of this kind.     

Association between novel indices of malnutrition-inflammation complex syndrome and cardiovascular disease in hemodialysis patients

Background: Inflammation and malnutrition are recognized as important risk factors for cardiovascular disease (CVD) in hemodialysis (HD) patients. Owing to substantial short‐term variability of serum C‐reactive protein (CRP), more reliable markers of malnutrition–inflammation complex syndrome should be sought with stronger associations with the risk of CVD in HD patients. We therefore explored the clinical relevance of a composite inflammatory index (prognostic inflammatory and nutritional index [PINI]) and of muscle protein mass indicators, derived from creatinine kinetics. Methods: This cross‐sectional study included 177 HD patients (89 women and 88 men; median age, 67.73 years). CVD and risk factors were assessed using medical charts, clinical examination, and biochemical measurements performed at inclusion. Lean body mass (LBM) was derived from creatinine kinetic modeling, whereas PINI was calculated as the ratio (CRP ×α1‐acid‐glycoprotein)/(albumin × transthyretin). Patients were divided according to the presence or absence of established CVD. Results: The traditional risk factors diabetes (odds ratio [OR], 5.83; p = 0.0045) and smoking (OR, 3.50; p < 0.02) were associated with an increase in prevalent CVD. Low transthyretin (OR, 3.79; p < 0.02) and high levels of CRP (OR, 2.70; p < 0.05), PINI (OR, 3.44; p < 0.02), observed LBM (OR, 3.01; p < 0.05), and the ratio of observed/expected LBM (OR, 4.24; p < 0.01) were associated with CVD after adjustment for age, sex, dialysis center, and dialysis vintage. After additional adjustment for diabetes and smoking, only PINI (OR, 2.85; p = 0.0446) and observed/expected LBM (OR, 2.96; p = 0.0361) were still significant. Conclusion: PINI and LBM are associated with increased relative risk for having CVD and could be used routinely to examine the degree of severity of malnutrition inflammation complex syndrome.     

Electrochemical nanofabrication using crystalline protein masks

We have developed a simple and robust method to fabricate nanoarrays of metals and metal oxides over macroscopic substrates using the crystalline surface layer (S-layer) protein of Deinococcus radiodurans as an electrodeposition mask. Substrates are coated by adsorption of the S-layer from a detergent-stabilized aqueous protein extract, producing insulating masks with 2-3 nm diameter solvent-accessible openings to the deposition substrate. The coating process can be controlled to achieve complete or fractional surface coverage. We demonstrate the general applicability of the technique by forming arrays of cuprous oxide (Cu(2)O), Ni, Pt, Pd, and Co exhibiting long-range order with the 18 nm hexagonal periodicity of the protein openings. This protein-based approach to electrochemical nanofabrication should permit the creation of a wide variety of two-dimensional inorganic structures.     

Effects of Glass Phase Additions and Stoichiometry on the Ba(Zn<Subscript>1/3</Subscript>X<Subscript>2/3</Subscript>)O<Subscript>3</Subscript> (<Emphasis Type="Italic">X</Emphasis> = Ta or Nb) Sinterability and Dielectric Properties

Ba(Zn_1/3X_2/3)O₃ materials where X = Ta or Nb (respectively named BZT and BZN) exhibit attractive properties suitable for applications in type I Multi Layer Ceramics Capacitors (MLCC). Nevertheless, to produce such components using Base Metal Electrodes such as copper, a significant reduction of their sintering temperature is required. The aim of this work is first to study the effects of glass phases additions and secondly the stoichiometry influence on the sintering temperature of BZT and BZN. It is shown for example, that our materials can be sintered in air at a temperature lowered by 450C when sintering agents (B₂O₃ with LiF) are combined with a slight non-stoichiometry. The sintered samples are characterised in terms of final density, microstructure and phase content and it was underlined that such modifications (additions and stoichiometry) does not affect the dielectric properties.