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Macromolecular X-ray crystallography is an important and powerful technique in drug discovery, used by pharmaceutical companies in the discovery process of new medicines. The detailed analysis of crystal structures of protein-ligand complexes allows the study of the specific interactions of a particular drug with its protein target at the atomic level. It is used to design and improve drugs. The starting point of these studies is the preparation of suitable crystals of complexes with potential ligands, which can be achieved by using different strategies described in this chapter. In addition, an introduction to X-ray crystallography is given, highlighting the fundamental steps necessary to determine the three-dimensional structure of protein-ligand complexes, as well as some of the tools and criteria to validate crystal structures available in databases.

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Analysis of x-ray spectra emitted by highly charged ions in an electron-cyclotron-resonance ion source (ECRIS) may be used as a tool to estimate the charge-state distribution (CSD) in the source plasma. For that purpose, knowledge of the electron energy distribution in the plasma, as well as the most important processes leading to the creation and de-excitation of ionic excited states are needed. In this work we present a method to estimate the ion CSD in an ECRIS through the analysis of the x-ray spectra emitted by the plasma. The method is applied to the analysis of a sulfur ECRIS plasma.

Analysis of x-ray spectra emitted by highly charged ions in an electron-cyclotron-resonance ion source (ECRIS) may be used as a tool to estimate the charge-state distribution (CSD) in the source plasma. For that purpose, knowledge of the electron energy distribution in the plasma, as well as the most important processes leading to the creation and de-excitation of ionic excited states are needed. In this work we present a method to estimate the ion CSD in an ECRIS through the analysis of the x-ray spectra emitted by the plasma. The method is applied to the analysis of a sulfur ECRIS plasma.

We study the contribution of the most important processes leading to the creation of excited states of Cl14+ ions from the ground configurations of Cl ions in an Electron Cyclotron Resonance Ion Source (ECRIS), which lead to the emission of K X-ray lines. Theoretical values for inner-shell excitation, K and KL ionization cross-sections, and energies and transition probabilities for the de-excitation processes are calculated in the framework of the Multi-Configuration Dirac-Fock (MCDF) method. With reasonable assumptions about the electron energy distribution, a theoretical K[alpha] X-ray spectrum is obtained, which reproduces closely a recent experimental result.

We study the contribution of the most important processes leading to the creation of excited states of Cl14+ ions from the ground configurations of Cl ions in an Electron Cyclotron Resonance Ion Source (ECRIS), which lead to the emission of K X-ray lines. Theoretical values for inner-shell excitation, K and KL ionization cross-sections, and energies and transition probabilities for the de-excitation processes are calculated in the framework of the Multi-Configuration Dirac-Fock (MCDF) method. With reasonable assumptions about the electron energy distribution, a theoretical K[alpha] X-ray spectrum is obtained, which reproduces closely a recent experimental result.

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The QED contribution to the energies of the circular (n, = n–1), 2n13, transitions have been calculated for several kaonic atoms throughout the periodic table, using the current world-average kaon mass. Calculations were done in the framework of the Klein-Gordon equation, with finite nuclear size, finite particle size, and all-order Uelhing vacuum polarization corrections, as well as Källén and Sabry and Wichmann and Kroll corrections. These energy level values are compared with other computed values. The circular transition energies are compared with available measured and theoretical transition energies. Electron screening is evaluated using a Dirac-Fock model for the electronic part of the wave function. The effect of electronic wave-function correlation is evaluated.Exo

The QED contribution to the energies of the circular (n, = n–1), 2n13, transitions have been calculated for several kaonic atoms throughout the periodic table, using the current world-average kaon mass. Calculations were done in the framework of the Klein-Gordon equation, with finite nuclear size, finite particle size, and all-order Uelhing vacuum polarization corrections, as well as Källén and Sabry and Wichmann and Kroll corrections. These energy level values are compared with other computed values. The circular transition energies are compared with available measured and theoretical transition energies. Electron screening is evaluated using a Dirac-Fock model for the electronic part of the wave function. The effect of electronic wave-function correlation is evaluated.

Energies of the circular (n, ℓ = n − 1) 1 less-than-or-equals, slant n less-than-or-equals, slant 20 levels have been calculated for hydrogenlike sigmonic atoms with 1 less-than-or-equals, slant Z less-than-or-equals, slant 92, using the current world average sigma mass, as well as the electronic shift in Σ− + Ne e− + nucleus systems, where Ne stands for the number of electrons. The electronic influence on sigmonic orbitals has also been investigated through the computation of the hyperfine structure and the anomalous Σ− magnetic moment effects in sigmonic Be 2p states.

Energies of the circular (n, ℓ = n − 1) 1 less-than-or-equals, slant n less-than-or-equals, slant 20 levels have been calculated for hydrogenlike sigmonic atoms with 1 less-than-or-equals, slant Z less-than-or-equals, slant 92, using the current world average sigma mass, as well as the electronic shift in Σ− + Ne e− + nucleus systems, where Ne stands for the number of electrons. The electronic influence on sigmonic orbitals has also been investigated through the computation of the hyperfine structure and the anomalous Σ− magnetic moment effects in sigmonic Be 2p states.Exo

The present work refers to an X-ray microtomography experiment aiming at the elucidation of some aspects regarding particle distribution in SiC-particle-reinforced functionally graded aluminium composites.
Precursor composites were produced by rheocasting. These were then molten and centrifugally cast to obtain the
functionally graded composites. From these, cylindrical samples, around 1 mm in diameter, were extracted, which were then irradiated with a X-ray beam produced at the European Synchrotron Radiation Facility.
The 3-D images were obtained in edge-detection mode. A segmentation procedure has been adapted in order to
separate the pores and SiC particles from the Al matrix. Preliminary results on the particle and pore distributions are presented.