Tumour necrosis factor-α and adenosine in endotoxin shockleading related cardiovascular symptoms

We have observed uncontrollable cardiogenic shock as a cardiovascular manifestation of systemic inflammatory response syndrome (SIRS) leading to death in a 62-year-old woman. The diagnosis of SIRS was based on the demonstration of endotoxinaemia, and highly elevated plasma levels of tumour necrosis factor (TNF)-α, and interleukin (IL)-10. We suggest that these cytokines may contribute to the terminal SIRS-related arrythmias, impaired myocardial contractility, as well as increased vascular permeability. In addition, the increased production of adenosine, a counter-regulatory mediator of inflammation, may also play a role in cardiodepression. We suggest a relationship between the action of TNF-α , IL-10 and adenosine in the pathogenesis of circulatory symptoms described above

Interplay between surface chemistry and performance of rutile-type catalysts for halogen production

Catalytic HBr oxidation is an integral step in the bromine-mediated functionalisation of alkanes to valuable chemicals. This study establishes the relationships between the mechanism of HBr oxidation over rutile-type oxides (RuO2, IrO2, TiO2) and their apparent catalytic performance. Comparison with the well-studied HCl oxidation revealed distinct differences in surface chemistry between HBr and HCl oxidation that impact the stability and activity of the catalysts. The kinetic fingerprints of both oxidation reactions over the three rutile-type oxides investigated are compared using temporal analysis of products, which substantiates the energy profiles derived from density functional theory. The quantitative determination of the halogen uptake under operando conditions using prompt gamma activation analysis demonstrates that RuO2 suffers from extensive subsurface bromination upon contact with hydrogen bromide, particularly at low temperature and low O2 : HBr ratios, which negatively affects the stability of the catalyst. TiO2 exhibits intrinsically low halogen coverage (30–50%) under all the conditions investigated, due to its unique defect-driven mechanism that renders it active and stable for Br2 production. On the contrary, for HCl oxidation TiO2 is inactive, and the chlorination of the highly active RuO2 is limited to the surface. Differences in the extent of surface halogenation of the materials were also confirmed by high-resolution transmission electron microscopy and explained by the DFT calculations. These insights into the molecular-level processes taking place under working conditions pave the way for the design of the next generation catalysts for bromine production

Supported CeO₂ catalysts in technical form for sustainable chlorine production

Bulk CeO2 has been recently reported as a promising catalyst for the oxidation of HCl to Cl2. In order to undertake the scale up of this system, various oxides (TiO2, Al2O3 , and low- and high-surface area ZrO2) have been evaluated as carriers. Supported CeO2 catalysts (3–20 wt.% Ce) prepared by dry impregnation were isothermally tested at the lab scale. Their performance was ranked as: CeO2/ZrO2 ≫ CeO2/Al2O3 ≥ CeO2/TiO2. Kinetic data revealed a lower activation energy and a similar activity dependence on the partial pressure of O2 for CeO2/ZrO2 compared to bulk CeO2. Pilot-scale testing over 3-mm pellets of this catalyst evidenced outstanding stability for 700 h on stream. In-depth characterization of the carriers and fresh catalysts by N2 sorption, Hg porosimetry, X-ray diffraction, temperature-programmed reduction with H2, Raman spectroscopy, electron microscopy, and in situ prompt gamma activation analysis, enabled to rationalize the different catalytic behavior of the materials. ZrO2 stabilizes nanostructures of CeO2 and a Ce–Zr mixed oxide phase, which offer high dispersion and improved oxidation properties. The catalyst also shows reduced chlorine uptake, and overall stands as a better Deacon material compared to bulk CeO2 and other supported systems. CeO2 is present on Al2O3 predominantly as well-distributed nanoparticles. Still, alumina does not induce any electronic effect, thus the supported phase behaves similarly to bulk ceria. TiO2, likely due to the structural collapse and dramatic sintering suffered during calcination, leads to the formation of very large ceria particles. Based on our results, CeO2/ZrO2 appears as a robust and cost-effective alternative to the current RuO2-based catalysts for large-scale chlorine recovery

Do observations on surface coverage-reactivity correlations always describe the true catalytic process? A case study on ceria

In situ (operando) investigations aim at establishing structure-function and/or coverage-reactivity correlations. Herein, we investigated the gas-phase HCl oxidation (4HCl + O2 → 2Cl2 + 2H2O) over ceria. Despite its remarkable performance, under low oxygen over-stoichiometry, this oxide is prone to a certain extent to subsurface/bulk chlorination, which leads to deactivation. In situ Prompt Gamma Activation Analysis (PGAA) studies evidenced that the chlorination rate is independent of the pre-chlorination degree but increases at lower oxygen over-stoichiometry, while dechlorination is effective in oxygen-rich feeds, and its rate is higher for a more extensively pre-chlorinated ceria. Even bulk CeCl3 could be transformed into CeO2 under oxygen excess. Electron Paramagnetic Resonance experiments strongly suggested that oxygen activation is inhibited by a high surface chlorination degree. The coverages of most abundant surface intermediates, OH and Cl, were monitored by in situ infrared spectroscopy and PGAA under various conditions. Higher temperature and p(O2) led to enhanced OH coverage, reduced Cl coverage, and increased reactivity. Variation of p(HCl) gave rise to opposite correlations, while raising p(Cl2) did not induce any measurable increase in the Cl coverage, despite the strong inhibition of the reaction rate. The results indicate that only a small fraction of surface sites is actively involved in the reaction, and most of the surface species probed in the in situ observation are spectators. Therefore, when performing in situ steady-state experiments, a large set of variables should be considered to obtain accurate conclusions

High-resolution study of the 113

The gamma-ray spectrum and the decay scheme of 114Cd obtained from a radiative neutron capture experiment on 113Cd samples are modelled in the framework of extreme statistical model. The unfolding of the experimental spectrum with proper normalization yields a total capture cross section of 21640 b and an average gamma-ray multiplicity of 4.1. Using the extreme statistical model the development of the low energy decay scheme of 114Cd is in progress. In the model the constant-temperature level density is used, where the temperature parameter was very sensitive to the shape of the modelled gamma-ray spectrum. Using this sensitivity T = 0.62 MeV was obtained with the constraint of good description of low energy level density and the level density at the binding energy. This is in full agreement with our earlier publication. For the description of the continuum shape of the unfolded spectrum the inclusion of low energy enhancement for the photon strength function was an important new addition

Radiative-capture cross sections for the La139(n,γ) reaction using thermal neutrons and structural properties of La140

A set of prompt partial γ-ray production cross sections from thermal neutron capture were measured for the 139La (n,γ) reaction using a guided beam of subthermal (thermal and cold) neutrons incident on a nat La2O3 target at the Prompt Gamma Activation Analysis facility of the Budapest Research Reactor. Absolute 140La cross sections were determined relative to the well-known comparator 35Cl(n,γ) cross sections from the irradiation of a stoichiometric nat LaCl3 sample. The total cross section for radiative thermal neutron capture on 139La from the sum of experimentally measured cross sections observed to directly feed the 140 La ground state was determined to be σ0 = 8.58(50) b. To assess completeness of the decay scheme and as a consistency check, the measured cross sections for transitions feeding the ground state from levels below a critical energy of Ec = 285 keV were combined with a modeled contribution accounting for ground-state feeding from the quasi continuum to arrive at a total cross section of σ0 = 9.36(74) b. In addition, a neutron-separation energy of Sn = 5161.001(21) keV was determined from a least-squares fit of the measured primary γ-ray energies to the low-lying levels of the 140La decay scheme. Furthermore, several nuclear structure improvements are proposed for the decay scheme. The measured cross-section and separation-energy results are comparable to earlier measurements of these quantities

Role of Hydrogen Species in Palladium-Catalyzed Alkyne Hydrogenation

Selective alkyne hydrogenation in the presence of carbon-carbon double bond compounds, for which Pd is an excellent catalyst, is a strategically important large-scale industrial process. Although in palladium, functionality and structure are closely interrelated, knowledge of the structure of Pd is insufficient as the interaction with the chemical environment causes drastic compositional changes near the subsurface region: while unselective hydrogenation proceeds in the presence of a β-hydride phase, selective hydrogenation can be achieved only in the presence of a near-surface Pd-C phase. Here, we show from a combination of in situ prompt gamma activation analysis and ab initio simulations based on density functional theory that (i) the presence of the Pd-C phase created under selective conditions implies a strong change in the surface and subsurface stability of hydrogen, (ii) there is still a slower exchange of bulk and surface hydrogen, and (iii) the reaction rate for selective hydrogenation is independent of the bulk H/Pd ratio