Synthesis of porous high-temperature superconductors via a melamine formaldehyde sacrificial template.

Nanostructured high-temperature superconductors YBa2Cu3O6+δ and Bi2Sr2CaCu2O8+δ were synthesised using a melamine formaldehyde sponge as a sacrificial template, via three solution-based approaches. In the case of YBa2Cu3O6+δ , a modified Pechini method produced a material with a superconducting transition at 92 K and a specific surface area of 4.22 m2 g-1. Further analysis with Hg porosimetry determined that the sponge exhibited a porosity of 82%. In the case of Bi2Sr2CaCu2O8+δ , this method produced a material that exhibited superconductivity at 86 K with a specific surface area of 9.62 m2 g-1. Hg-porosimetry determined that the BSCCO sponge exhibited a porosity of 78%.

Improved photodegradation of anionic dyes using a complex graphitic carbon nitride and iron-based metal-organic framework material.

Introducing heterostructures to graphitic carbon nitrides (g-C3N4) can improve the activity of visible-light-driven catalysts for the efficient treatment of multiple toxic pollutants in water. Here, we report for the first time that a complex material can be constructed from oxygen-doped g-C3N4 and a MIL-53(Fe) metal-organic framework using facile hydrothermal synthesis and recycled polyethylene terephthalate from plastic waste. The novel multi-walled nanotube structure of the O-g-C3N4/MIL-53(Fe) composite, which enables the unique interfacial charge transfer at the heterojunction, showed an obvious enhancement in the separation efficiency of the photochemical electron-hole pairs. This resulted in a narrow bandgap energy (2.30 eV, compared to 2.55 eV in O-g-C3N4), high photocurrent intensity (0.17 mA cm-2, compared to 0.12 mA cm-2 and 0.09 mA cm-2 in MIL-53(Fe) and O-g-C3N4, respectively) and excellent catalytic performance in the photodegradation of anionic azo dyes (95% for RR 195 and 99% for RY 145 degraded after 4 h, and only a minor change in the efficiency observed after four consecutive tests). These results demonstrate the development of new catalysts made from waste feedstocks that show high stability, ease of fabrication and can operate in natural light for environmental remediation.

Crystal structure and Hirshfeld surface analysis of (E)-3-(3-iodo-phen-yl)-1-(4-iodo-phen-yl)prop-2-en-1-one.

The title compound, C15H10I2O, is a halogenated chalcone formed from two iodine substituted rings, one para-substituted and the other meta-substituted, linked through a prop-2-en-1-one spacer. In the mol-ecule, the mean planes of the 3-iodo-phenyl and the 4-iodo-phenyl groups are twisted by 46.51 (15)°. The calculated electrostatic potential surfaces show the presence of σ-holes on both substituted iodines. In the crystal, the mol-ecules are linked through type II halogen bonds, forming a sheet structure parallel to the bc plane. Between the sheets, weak inter-molecular C-H⋯π inter-actions are observed. Hirshfeld surface analysis showed that the most significant contacts in the structure are C⋯H/H⋯C (31.9%), followed by H⋯H (21.4%), I⋯H/H⋯I (18.4%). I⋯I (14.5%) and O⋯H/H⋯O (8.1%).

Size-dependent melting point depression of nickel nanoparticles.

We investigate the phase-transition behaviour of nickel nanoparticles (3-6 nm) via dynamic TEM. The nanoparticles were synthesized within a reverse microemulsion and then monitored via dynamic TEM simultaneously while undergoing controlled heating. The size-dependent melting point depression experimentally observed is compared with, and is in good agreement with existing thermodynamic and molecular dynamic predictions.

The effects of repeated Toll-like receptors 2 and 4 stimulation in COPD alveolar macrophages.

Background: COPD is a progressive inflammatory airway disease characterized by increased numbers of alveolar macrophages in the lungs. Bacterial colonization of the lungs is a common feature in COPD and can promote inflammation through continual and repeated Toll-like receptor (TLR) stimulation. We have studied the response of COPD alveolar macrophages to repetitive stimulation with TLR2 and TLR4 ligands. We investigated the effect of sequential stimulation with different ligands to determine whether this results in tolerance or amplification of the immune response. Methods: We stimulated alveolar macrophages from COPD patients (n=9) and smokers (n=8) with the TLR4 agonist lipopolysaccharide (LPS) or the TLR2 agonist Pam3CSK4 for 24 hours before restimulating again for 24 hours. Cytokine protein release and gene expression were investigated. Results: Repetitive stimulation of COPD and smokers macrophages with LPS for both 24-hour periods caused a reduction in tumor necrosis factor α, CCL5, and IL-10 production compared to cells that were not exposed initially to LPS. IL-6 and CXCL8 production were not significantly altered following repetitive LPS stimulation. The same pattern was observed for repeated stimulation with Pam3CSK4. Using COPD macrophages, LPS followed by Pam3CSK4 stimulation increased the levels of all cytokines compared to media followed by Pam3CSK4. Conclusion: TLR tolerance in COPD alveolar macrophages occurs after repetitive stimulation with the same TLR ligand, but this only occurs for selected cytokines. CXCL8 production is not reduced after repetitive TLR stimulation with the same ligand; this may be an important mechanism for the increased CXCL8 levels that have been observed in COPD. We showed that TLR4 stimulation followed by TLR2 stimulation does not cause tolerance, but enhances cytokine production. This may be a relevant mechanism by which bacteria cause excessive inflammation in COPD patients.

The MIF Antagonist ISO-1 Attenuates Corticosteroid-Insensitive Inflammation and Airways Hyperresponsiveness in an Ozone-Induced Model of COPD.

INTRODUCTION: Macrophage migration inhibitory factor (MIF) is an inflammatory cytokine associated with acute and chronic inflammatory disorders and corticosteroid insensitivity. Its expression in the airways of patients with chronic obstructive pulmonary disease (COPD), a relatively steroid insensitive inflammatory disease is unclear, however. METHODS: Sputum, bronchoalveolar lavage (BAL) macrophages and serum were obtained from non-smokers, smokers and COPD patients. To mimic oxidative stress-induced COPD, mice were exposed to ozone for six-weeks and treated with ISO-1, a MIF inhibitor, and/or dexamethasone before each exposure. BAL fluid and lung tissue were collected after the final exposure. Airway hyperresponsiveness (AHR) and lung function were measured using whole body plethysmography. HIF-1α binding to the Mif promoter was determined by Chromatin Immunoprecipitation assays. RESULTS: MIF levels in sputum and BAL macrophages from COPD patients were higher than those from non-smokers, with healthy smokers having intermediate levels. MIF expression correlated with that of HIF-1α in all patients groups and in ozone-exposed mice. BAL cell counts, cytokine mRNA and protein expression in lungs and BAL, including MIF, were elevated in ozone-exposed mice and had increased AHR. Dexamethasone had no effect on these parameters in the mouse but ISO-1 attenuated cell recruitment, cytokine release and AHR. CONCLUSION: MIF and HIF-1α levels are elevated in COPD BAL macrophages and inhibition of MIF function blocks corticosteroid-insensitive lung inflammation and AHR. Inhibition of MIF may provide a novel anti-inflammatory approach in COPD.

Synthesis of phase pure praseodymium barium copper iron oxide.

The control of crystallization of praseodymium barium copper iron oxide, an intermediate temperature solid oxide fuel cell cathode material, has been demonstrated for the first time using a biotemplated sol-gel synthesis technique. The results obtained showed significant improvement in purity, synthesis time, surface area and simplicity over that previously reported.