Continuous gas phase methane oxidation using nitrous oxide over Fe-based zeolite

This study investigates the direct continuous gas phase methane partial oxidation using nitrous oxide (N2O) over a range of Fe exchanged MFI framework catalysts. It has been shown that the required active species, namely α-oxygen can be generated over the biomimetic catalyst (Fe/ZSM-5) after heating treatment with N2O. The hydrogen abstraction step is followed to cleave the C-H bond to form methoy and hydroxy groups on the Fe sites. Investigating the influence of acid sites in continuous methane oxidation with N2O over Fe/ MFI zeolites revealed that Bronsted acidity of the Fe-zeolite catalyst supports the α-oxygen active species for the hydrogen abstraction to activate methane. The calcination treatment could cause a significantly decrease for both the Brønsted and Lewis acidity of Fe/ZSM-5 via the migration of aluminium as the catalyst treatment temperature increases. A substantial decrease is observed in catalytic performance following such alteration. The desired methanol could undergo further transformation to ethene follow by coke which is observed to behave similar to the methanol to olefin (MTO) reaction over zeolite framework. This side reaction path led to poor carbon balance and limited selectivity to partial oxygenates. The subsequent kinetic study on methane oxidation over 2 wt % Fe/ZSM-5 using N2O for both water-free and water-assisted (20 %) system has shown that the addition of water significantly improves methanol selectivity. A delplot technique was applied after performing a series of reactions using different catalyst mass for both system to identify the product rank of reaction products. Control experiments carried out in the absence of methane shown that the N2O decomposition rate also proceed similar to the full reaction mixture

Investigating the influence of acid sites in continuous methane oxidation with N2O over Fe/MFI zeolites

Methane oxidation using N2O was carried out with Fe–MFI zeolite catalysts at 300 °C. Methane conversion over Fe–ZSM-5, Fe–silicalite-1 and Fe–TS-1 indicates that Brønsted acidity is required to support the Fe-based alpha-oxygen active site for the important initial hydrogen abstraction step. Increasing the calcination temperature of Fe–ZSM-5 from 550 to 950 °C showed that the catalyst retained the MFI structure. However, at 950 °C the Brønsted and Lewis acid sites were altered significantly due to the migration of aluminium, which led to a significant decrease in catalytic performance. Over Fe–ZSM-5 the desired partial oxidation product, methanol was observed to undergo a reaction path similar to the methanol to olefin (MTO) process, which predominately produced ethene and subsequently produced coke. Methanol control experiments over Fe–silicalite-1, Fe–ZSM-5, Fe–TS-1 and H–ZSM-5 indicated that with the presence of Brønsted acidity the catalysts were more effective at forming ethene and subsequent aromatic species from DME, which resulted in an increased level of catalyst fouling. The implication of these observations is that the desorption of methanol is crucial to afford high mass balances and selectivity, however, Brønsted acid sites appear to slow this rate. These sites appear to effectively retain methanol and DME under reaction conditions, leading to low mass balances being observed. Our results confirm that to afford efficient and continuous methane oxidation by N2O, the catalytic active site must be Fe coordinated to Al

Selective oxidation of methane to methanol using supported AuPd catalysts prepared by stabilizer-free sol-immobilization

The selective oxidation of methane to methanol, using H₂O₂, under mild reaction conditions was studied using bimetallic 1 wt % AuPd/TiO₂ prepared by stabilizer-free sol-immobilization. The as-prepared catalysts exhibited low, unselective oxidation activity and deleterious H₂O₂ decomposition, which was ascribed to the small mean particle size of the supported AuPd nanoparticles. Heat treatments were employed to facilitate particle size growth, yielding an improvement in the catalyst turnover frequency and decreasing the H₂O₂ decomposition rate. The effect of support phase was studied by preparing a range of AuPd catalysts supported on rutile TiO₂. The low surface area rutile TiO₂ yielded catalysts with effective oxygenate production but poor H₂O₂ utilization. The influence of the rutile-TiO₂ support was investigated further by producing catalysts with a lower metal loading to maintain a consistent metal loading per square meter compared to the 1 wt % AuPd/P25 TiO₂ catalyst. When calcined at 800 °C, the 0.13 wt % AuPd catalyst demonstrated significantly improved turnover frequency of 103 h^–1. In contrast, the turnover frequency was found to be ca. 2 h^–1 for the rutile-supported 1 wt % AuPd catalyst calcined at 800 °C. The catalysts were probed by electron microscopy and X-ray photoelectron spectroscopy to understand the influence of particle size and oxidation state on the utilization of H₂O₂ and oxygenate productivity. This work shows that the key to highly active catalysts involves the prevention of deleterious H₂O₂ decomposition, and this can be achieved through carefully controlling the nanoparticle size, metal loading, and metal oxidation state

Characterization of the commercially-available fluorescent chloroquine-BODIPY conjugate, LynxTag-CQGREEN, as a marker for chloroquine resistance and uptake in a 96-well plate assay

Chloroquine was a cheap, extremely effective drug against Plasmodium falciparum until resistance arose. One approach to reversing resistance is the inhibition of chloroquine efflux from its site of action, the parasite digestive vacuole. Chloroquine accumulation studies have traditionally relied on radiolabelled chloroquine, which poses several challenges. There is a need for development of a safe and biologically relevant substitute. We report here a commercially-available green fluorescent chloroquine-BODIPY conjugate, LynxTag-CQGREEN, as a proxy for chloroquine accumulation. This compound localized to the digestive vacuole of the parasite as observed under confocal microscopy, and inhibited growth of chloroquine-sensitive strain 3D7 more extensively than in the resistant strains 7G8 and K1. Microplate reader measurements indicated suppression of LynxTag-CQGREEN efflux after pretreatment of parasites with known reversal agents. Microsomes carrying either sensitive or resistant-type PfCRT were assayed for uptake; resistant-type PfCRT exhibited increased accumulation of LynxTag-CQGREEN, which was suppressed by pretreatment with known chemosensitizers. Eight laboratory strains and twelve clinical isolates were sequenced for PfCRT and Pgh1 haplotypes previously reported to contribute to drug resistance, and pfmdr1 copy number and chloroquine IC50s were determined. These data were compared with LynxTag-CQGREEN uptake/fluorescence by multiple linear regression to identify genetic correlates of uptake. Uptake of the compound correlated with the logIC50 of chloroquine and, more weakly, a mutation in Pgh1, F1226Y

Towards a global partnership model in interprofessional education for cross-sector problem-solving

Objectives A partnership model in interprofessional education (IPE) is important in promoting a sense of global citizenship while preparing students for cross-sector problem-solving. However, the literature remains scant in providing useful guidance for the development of an IPE programme co-implemented by external partners. In this pioneering study, we describe the processes of forging global partnerships in co-implementing IPE and evaluate the programme in light of the preliminary data available. Methods This study is generally quantitative. We collected data from a total of 747 health and social care students from four higher education institutions. We utilized a descriptive narrative format and a quantitative design to present our experiences of running IPE with external partners and performed independent t-tests and analysis of variance to examine pretest and posttest mean differences in students’ data. Results We identified factors in establishing a cross-institutional IPE programme. These factors include complementarity of expertise, mutual benefits, internet connectivity, interactivity of design, and time difference. We found significant pretest–posttest differences in students’ readiness for interprofessional learning (teamwork and collaboration, positive professional identity, roles, and responsibilities). We also found a significant decrease in students’ social interaction anxiety after the IPE simulation. Conclusions The narrative of our experiences described in this manuscript could be considered by higher education institutions seeking to forge meaningful external partnerships in their effort to establish interprofessional global health education

SCANNING THE MEKONG RIVER’S HORIZONS: HOW MIGHT HYDROPOWER DAMS ALONG THE RIVER ALTER THE COURSE OF INTERSTATE RELATIONS ACROSS MAINLAND SOUTHEAST ASIA?

Bachelor'sBACHELOR OF SOCIAL SCIENCES (HONOURS

Effect of lipoproteins and homocysteine on vascular endothelial function

published_or_final_versionPharmacologyMasterMaster of Philosoph

Salutogenic-based interventions among community-dwelling older adults: a systematic review and meta-analysis.

10.1093/heapro/daac007Health Promotion Internationa