Energy resolved X-ray fluorescence imaging based on a micropattern gas detector

A simple system for energy resolved X-ray fluorescence imaging using a room temperature, 2-D sensitive Micro-Hole and Strip Plate (MHSP) operating in pure xenon is proposed. The Micro-Hole and Strip Plate is an electron multiplier with two stages of avalanche production, one of them in the holes and another one in the anode strips. The X-ray interaction via photoelectron absorption in the xenon produces a number of electrons proportional to the incoming X-ray energy. The electron cloud is, then, amplified in the two amplification stages, resulting in a charge pulse that is also proportional to the detected X-ray energy. The 2-D capability is achieved in the Micro-Hole and Strip Plate by using two orthogonal resistive lines, one connecting the anode strips on the bottom face of the Micro-Hole and Strip Plate and the other one connecting the strips structured on the Micro-Hole and Strip Plate top surface. This low cost detector has an active area of 28 × 28 mm², an intrinsic position resolution of σ∼ 125 µm, an energy resolution of about 825 eV (Full Width at Half Maximum) at 5.9 keV and a count rate capability as high as 0.5 MHz. Fluorescence images were obtained by irradiating the sample with X-rays and using a pinhole placed between the sample and the detector window. Elemental map discrimination for different samples, image amplification and detector parameters, are presented.     

The analysis of composite laminated beams using a 2D interpolating meshless technique

Laminated composite materials are widely implemented in several engineering constructions. For its relative light weight, these materials are suitable for aerospace, military, marine, and automotive structural applications. To obtain safe and economical structures, the modelling analysis accuracy is highly relevant. Since meshless methods in the recent years achieved a remarkable progress in computational mechanics, the present work uses one of the most flexible and stable interpolation meshless technique available in the literature—the Radial Point Interpolation Method(RPIM).Here, a 2 D approach is considered to numerically analyse composite laminated beams. Both the meshless formulation and the equilibrium equations ruling the studied physical phenomenon are presented with detail. Several benchmark beam examples are studied and the results are compared with exact solutions available in the literature and the results obtained from a commercial finite element software. The results show the efficiency and accuracy of the proposed numeric technique.     

An original catalytic synthesis of boriran-1-ols

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Synthesis of new binary porphyrin–cyanine conjugates and their self-aggregation in organic-aqueous media

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A new member of the cationic dinitrosyl iron complexes family incorporating N-ethylthiourea is effective against human HeLa and MCF-7 tumor cell lines

A new analog of the active site of mononuclear dinitrosyl [1Fe–2S] proteins, [C₃N₂H₈SFe(NO)₂Cl][Fe(NO)₂(C₃N₂H₈S)₂]⁺Cl^? (I), has been synthesized by reacting NO with an aqueous mixture of iron(II) sulfate and N-ethylthiourea in acidic medium. The structure and properties of the complex were studied by X-ray diffraction, IR, Mössbauer, and EPR spectroscopy, in addition to quantum chemical calculations. Complex I spontaneously generates NO in protic media. The cytotoxicity of I was investigated against human cervical carcinoma (HeLa), breast cancer (MCF7), and non-immortalized (FetMCS) cell lines. The cytotoxicity of I against HeLa is similar to that of anticancer agents currently used clinically (platinum complexes), but I is 10 times less toxic in normal cells. The cytotoxicity of MCF7 cells to I is low.     

Three solutions for a nonlocal problem with critical growth

The main goal of this work is to prove the existence of three different solutions (one positive, one negative and one with nonconstant sign) for the equation ${(?{\mathrm{\Delta }}_p)}^{s}u=|u{|}^{p_s^{?}?2}u+\lambda f(x,u)$ in a bounded domain with Dirichlet condition, where ${(?{\mathrm{\Delta }}_p)}^s$ is the well known p-fractional Laplacian and $p_s^{?}=\frac{np}{n?sp}$ is the critical Sobolev exponent for the non local case. The proof follows the ideas of [28] and is based in the extension of the Concentration Compactness Principle for the p-fractional Laplacian [20] and Ekeland's variational Principle [7].