Inflammatory bowel diseases (IBD) are chronic, relapsing disorders affecting gastrointestinal (GI) tract and associated with intestinal mucosa damage and inflammation. The principal therapeutic goals in IBD include control of the intestinal inflammation and treatment of the major symptoms, mainly abdominal pain and diarrhea. Current therapeutic strategies for IBD rely on the use of non-specific anti-inflammatory agents and immunosuppressive drugs (e.g. aminosalicylates, monoclonal antibodies, and antibiotics), which cause severe side effects, and - in a significant number of patients - do not induce long-term benefits. In this review, we summarize the epidemiology and the most important risk factors of IBD, including genetic, immunological and environmental. Our main focus is to discuss pharmacological targets for current and future treatments of IBD.
The dissociative electron attachment (DEA) to benzoic acid (C6H5COOH) has been studied using an experimental crossed beam setup of a quadrupole mass spectrometer and a trochoidal electron monochromator. Relative partial cross sections for the DEA to produce negative ion fragments show the main channels for dissociation. The comparison of the present results with the ultraviolet photoelectron spectrum of benzoic acid [J. Meeks, A. Wahlborg, and S. P. McGlynn, J. Electron Spectrosc. Relat. Phenom. 22, 43 (1981)] implies that most DEA bands in the high energy range are due to Feshbach resonances with double occupation of diffuse Rydberg-like orbitals. The measurements are supported by density functional theory calculations of the threshold energies.
In this contribution the dissociative electron attachment to metabolites found in aerobic organisms, namely oxaloacetic and citric acids, was studied both experimentally by means of a crossed-beam setup and theoretically through density functional theory calculations. Prominent negative ion resonances from both compounds are observed peaking below 0.5 eV resulting in intense formation of fragment anions associated with a decomposition of the carboxyl groups. In addition, resonances at higher energies (3–9 eV) are observed exclusively from the decomposition of the oxaloacetic acid. These fragments are generated with considerably smaller intensities. The striking findings of our calculations indicate the different mechanism by which the near 0 eV electron is trapped by the precursor molecule to form the transitory negative ion prior to dissociation. For the oxaloacetic acid, the transitory anion arises from the capture of the electron directly into some valence states, while, for the citric acid, dipole- or multipole-bound states mediate the transition into the valence states. What is also of high importance is that both compounds while undergoing DEA reactions generate highly reactive neutral species that can lead to severe cell damage in a biological environment.
Gold-containing compounds offer many
applications in nanoscale
materials science, and electron-beam methods are versatile for shaping
nanostructures. In this study, we report the energy-selective fragmentation
of chloro(dimethyl sulfide)gold(I) (ClAuS(CH3)2) induced by slow electrons. We observe the resonant formation of
four fragment anions, namely [Cl]−, [S]−, [CH2S]−, and [ClAuH···SH]−, which are generated in the energy range of 0–9
eV. The predominant fragment anion is formed below 1 eV from the cleavage
of a single Au–Cl bond to produce the [Cl]− anion. The resonant states and the energetics of the fragmentation
are investigated by DFT methods. These findings may contribute to
future strategies in the elaboration of specific nanomaterials or
for selective chemistry using electron-beam techniques.
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