SOLUBILITY LIMIT OF DOPANTS IN SILICON IRRADIATED BY RUBY LASER

The solubility of several dopants (Sb, Ga, Bi, In) in laser treated silicon has been investigated. The dopants were introduced by vacuum deposition followed by a ruby laser irradiation. Their solubility was determined by Rutherford backscattering spectrometry measurements in channeling and random conditions. In all cases a solubility limit Cmℓ higher than the equilibrium solubility was found and a simple correlation with the equilibrium distribution coefficient kO could be established : Cmℓ = 8.6 × 1021 k0.51O cm-3

Fracture Roughness Scaling: a case study on planar cracks

Using a multi-resolution technique, we analyze large in-plane fracture fronts moving slowly between two sintered Plexiglas plates. We find that the roughness of the front exhibits two distinct regimes separated by a crossover length scale $\delta^*$. Below $\delta^*$, we observe a multi-affine regime and the measured roughness exponent $\zeta_{\parallel}^{-} = 0.60\pm 0.05$ is in agreement with the coalescence model. Above $\delta^*$, the fronts are mono-affine, characterized by a roughness exponent $\zeta_{\parallel}^{+} = 0.35\pm0.05$, consistent with the fluctuating line model. We relate the crossover length scale to fluctuations in fracture toughness and the stress intensity factor

PULSED ELECTRON BEAM ANNEALING OF As AND B IMPLANTED SILICON

p-type (100) silicon wafers have been implanted either by As or B ions at 20 and 200 keV energies and doses of 1016cm-2. Pulsed electron beam annealing has been performed with fluences of 1.1 and 1.4 J/cm2 using a mean electron energy of 15 keV. The pulse duration was 50 ns. The annealed layers have been investigated by Rutherford backscattering under random and channeling conditions and by S.I.M.S. profiling. Good crystal regrowth and high dopant activation occur in all cases except for the 200 keV Boron implant. Impurities redistribution is observed but no significant segregation effects appear. The experimental profiles are in good agreement with a diffusion model using a modified green function solution and taking into account dopant diffusion in liquid phase and the computed melt front location. The deduced diffusion coefficient are in the 5.10-5cm2/s range for boron and 2.10-4cm2/s range for arsenic

INTERACTION BETWEEN ARGON AND DOPANTS IN SPUTTERED a-Si : H

The concentrations of As, B, H, Ar and Si in sputtered a-Si : H are measured by helium Rutherford backscattering and nuclear reactions analysis. Excess or deficit of hydrogen and argon by comparison with intrinsic a-Si : H are found in presence of dopants at high deposition rate. This is related to the plasma deposition method and would suggest micro grain structure in the deposited layer

Determination of left ventricular wall thickness and muscle mass by intravenous digital subtractionangiocardiography: validation of the method

Left ventricular (LV) wall thickness and muscle mass are important measures of LV hypertrophy. In 24 patients LV end-diastolic wall thickness and muscle mass were determined (two observers) by digital subtraction angiocardiography (DSA) and conventional LV angiocardiography (LVA). Wall thickness was determined over the anterolateral wall of the left ventricle according to the technique of Rackley (method 1) or by planimetry (method 2). Seventeen patients were studied at rest and seven during dynamic exercise. Wall thickness correlated well between LVA and DSA; the best correlations were obtained by a combined subtraction mode using either method 1 or 2 (method 1, r≥0-80; method2, r≥0. 75). The standard error of estimate of the mean (SEE) was slightly lower for method 2 (≤ 10%) than for method 1 (≤ 13%). DSA significantly overestimated wall thickness by 5-7% with method 1 and underestimated by 12-14% with method 2. Muscle mass correlated well between LVA and DSA; the SEE was ≤ 15% for method 1 and≤ 12% for method 2. Overestimation of muscle mass by DSA was 7-11% with method 1 and underestimation was 13-15% with method 2.It is concluded that LV wall thickness can be determined accurately by DSA with an SEE ranging between 10 and 13%. Determination of LV muscle mass is slightly less accurate and the SEE is slightly larger ranging between 13 to 17%. With method 1, wall thickness and muscle mass were over estimated and with method 2 underestimate

Nutrients limitation of primary productivity in the Southeast Pacific (BIOSOPE cruise)

Revue sans Comité de lectureInternational audienceIron is an essential nutrient involved in a variety of biological processes in the ocean, including photosynthesis, respiration and nitrogen fixation. Atmospheric deposition of aerosols is recognized as the main source of iron for the surface ocean. In high nutrient, low chlorophyll areas, it is now clearly established that iron limits phytoplankton productivity but its biogeochemical role in low nutrient, low chlorophyll environments has been poorly studied. We investigated this question in the unexplored southeast Pacific, arguably the most oligotrophic area of the global ocean. Situated far from any continental aerosol source, the atmospheric iron flux to this province is amongst the lowest of the world ocean. Here we report that, despite low dissolved iron concentrations (~0.1 nmol l-1) measured across the whole gyre (3 stations situated in the center, the western and the eastern edge), photosynthesis and primary productivity are only limited by iron availability at the border of the gyre, but not in the center. The seasonal stability of the gyre has apparently allowed for the development of populations acclimated to these extreme oligotrophic conditions. Moreover, despite clear evidence of nitrogen limitation in the central gyre, we were unable to measure nitrogen fixation in our experiments, even after iron and/or phosphate additions, and cyanobacterial nifH gene abundances were extremely low compared to the North Pacific Gyre. The South Pacific gyre is therefore unique with respect to the physiological status of its phytoplankton populations

Patients' and urologists' preferences for prostate cancer treatment: A discrete choice experiment

__Abstract__ Background: Patients' preferences are important for shared decision making. Therefore, we investigated patients' and urologists' preferences for treatment alternatives for early prostate cancer (PC). Methods: A discrete choice experiment was conducted among 150 patients who were waiting for their biopsy results, and 150 urologists. Regression analysis was used to determine patients' and urologists' stated preferences using scenarios based on PC treatment modality (radiotherapy, surgery, and active surveillance (AS)), and risks of urinary incontinence and erectile dysfunction.Results:The response rate was 110 out of 150 (73%) for patients and 50 out of 150 (33%) for urologists. Risk of urinary incontinence was an important determinant of both patients' and urologists' stated preferences for PC treatment (P<0.05). Treatment modality also influenced patients' stated preferences (P<0.05), whereas the risk of erectile dysfunction due to radiotherapy was mainly important to urologists (P<0.05). Both patients and urologists preferred AS to radical treatment, with the exception of patients with anxious/depressed feelings who preferred radical treatment to AS. Conclusion: Although patients and urologists generally may prefer similar treatments for PC, they showed different trade-offs between various specific treatment aspects. This implies that urologists need to be aware of potential differences compared with the patient's perspective on treatment decisions in shared decision making on PC treatment

Integrating transposable elements in the 3D genome

Chromosome organisation is increasingly recognised as an essential component of genome regulation, cell fate and cell health. Within the realm of transposable elements (TEs) however, the spatial information of how genomes are folded is still only rarely integrated in experimental studies or accounted for in modelling. Whilst polymer physics is recognised as an important tool to understand the mechanisms of genome folding, in this commentary we discuss its potential applicability to aspects of TE biology. Based on recent works on the relationship between genome organisation and TE integration, we argue that existing polymer models may be extended to create a predictive framework for the study of TE integration patterns. We suggest that these models may offer orthogonal and generic insights into the integration profiles (or "topography") of TEs across organisms. In addition, we provide simple polymer physics arguments and preliminary molecular dynamics simulations of TEs inserting into heterogeneously flexible polymers. By considering this simple model, we show how polymer folding and local flexibility may generically affect TE integration patterns. The preliminary discussion reported in this commentary is aimed to lay the foundations for a large-scale analysis of TE integration dynamics and topography as a function of the three-dimensional host genome