Synthesis and characterization of oxyanion (phosphate, sulfate) doped Ba2_2Sc2_2−_-y_yGay_yO5_5

In this paper we examine the effect of partial substitution of Ga for Sc in the oxyanion (phosphate, sulfate) containing perovskites, Ba2Sc$_2$$_-$$_x$P$_x$O$_5$$_+$$_x$ and Ba$_2$S$_c$$_2$$_-$$_x$S$_x$O$_5$$_+$3$_x$$_/$$_2$ with the samples analysed through a combination of X-ray diffraction, TGA, Raman spectroscopy and conductivity measurements. The results demonstrate that in both cases, Ga can be incorporated in place of Sc up to 40%. In order to accommodate the increasing Ga content, a reduction in the oxyanion content is required. Thus for the highest Ga content sample achieved, only 10% oxyanion incorporation was achieved giving endmember compositions of Ba$_2$S$_c$Ga$_0$$_.$$_8$P$_0$$_.$$_2$O$_5$$_.$$_2$ and Ba$_2$S$_c$Ga$_0$$_.$$_8$S$_0$$_.$$_2$O$_5$$_.$$_3$ for phosphate and sulfate doping respectively. While the Ga doping was shown to significantly improve the stability of the systems towards CO$_2$ containing atmospheres, conductivity measurements showed a reduction in the conductivity with increasing Ga content

Synthesis and characterisation of novel oxyanion doped materials for use in solid oxide fuel cells

In this thesis the work presented focused on the doping of oxyanions, borate, silicate, sulfate and phosphate, into different materials with the perovskite structure for use as electrolytes or cathodes in solid oxide fuel cells. Phosphate and sulfate doping was shown to have been carried out successfully on gallium doped barium and strontium scandates. They all adopted the cubic perovskite structures with the presence of oxyanions confirmed by Raman spectroscopy. These samples were found to have improved stability to CO2 atmospheres with increasing gallium content. Phosphate doping was also carried out on doped barium cerates and was found to lower the conductivity while not leading to improved stability. Oxyanion doped barium stannates were investigated and showed a lower conductivity on oxyanion doping and borate doped samples showed an improved stability in reducing atmospheres. Following on from earlier work on silicate doping in perovskite cathode materials silicon doping was carried out on (Ca/Sr)2MnFe1-xSixO6-δ which resulted in the formation of cubic perovskites with a mixed oxidation state on the B site. Conductivity and area specific resistance data were collected for the samples showing an initial improvement on silicon doping for two of the series

Investigation into the incorporation of phosphate into BaCe1-yAyO3-y/2 (A=Y, Yb, In)

In this paper we examine the effect of doping phosphate into BaCe1−yAyO3−y/2 (A = Y, Yb, In). The samples were analysed through a combination of X-ray diffraction, TGA, Raman spectroscopy and conductivity measurements. The results showed that phosphate could be incorporated into this system up to the 10% doping level, although this required an increased Y/Yb/In content, e.g., BaCe0.6(Y/In/Yb)0.3P0.1O2.9. The phosphate doping was, however, shown to lead to a decrease in conductivity; although at low phosphate levels high conductivities were still observed, e.g., for BaCe0.65Y0.3P0.05O2.875, σ = 4.3 × 10−3 S cm−1 at 600 °C in wet N2. In terms of the effect of phosphate incorporation on the CO2 stability, it was shown to lead to a small improvement for the In containing samples, whereas the yttrium doped compositions showed no change in CO2 stability

Getting shot of elves: healing, witchcraft and fairies in the Scottish witchcraft trials

This paper re-examines the evidence of the Scottish witchcraft trials for beliefs associated by scholars with "elf-shot." Some supposed evidence for elf-shot is dismissed, but other material illuminates the interplay between illness, healing and fairy-lore in early modern Scotland, and the relationship of these beliefs to witchcraft itself

Adjunctive rifampicin for Staphylococcus aureus bacteraemia (ARREST): a multicentre, randomised, double-blind, placebo-controlled trial.

BACKGROUND: Staphylococcus aureus bacteraemia is a common cause of severe community-acquired and hospital-acquired infection worldwide. We tested the hypothesis that adjunctive rifampicin would reduce bacteriologically confirmed treatment failure or disease recurrence, or death, by enhancing early S aureus killing, sterilising infected foci and blood faster, and reducing risks of dissemination and metastatic infection. METHODS: In this multicentre, randomised, double-blind, placebo-controlled trial, adults (≥18 years) with S aureus bacteraemia who had received ≤96 h of active antibiotic therapy were recruited from 29 UK hospitals. Patients were randomly assigned (1:1) via a computer-generated sequential randomisation list to receive 2 weeks of adjunctive rifampicin (600 mg or 900 mg per day according to weight, oral or intravenous) versus identical placebo, together with standard antibiotic therapy. Randomisation was stratified by centre. Patients, investigators, and those caring for the patients were masked to group allocation. The primary outcome was time to bacteriologically confirmed treatment failure or disease recurrence, or death (all-cause), from randomisation to 12 weeks, adjudicated by an independent review committee masked to the treatment. Analysis was intention to treat. This trial was registered, number ISRCTN37666216, and is closed to new participants. FINDINGS: Between Dec 10, 2012, and Oct 25, 2016, 758 eligible participants were randomly assigned: 370 to rifampicin and 388 to placebo. 485 (64%) participants had community-acquired S aureus infections, and 132 (17%) had nosocomial S aureus infections. 47 (6%) had meticillin-resistant infections. 301 (40%) participants had an initial deep infection focus. Standard antibiotics were given for 29 (IQR 18-45) days; 619 (82%) participants received flucloxacillin. By week 12, 62 (17%) of participants who received rifampicin versus 71 (18%) who received placebo experienced treatment failure or disease recurrence, or died (absolute risk difference -1·4%, 95% CI -7·0 to 4·3; hazard ratio 0·96, 0·68-1·35, p=0·81). From randomisation to 12 weeks, no evidence of differences in serious (p=0·17) or grade 3-4 (p=0·36) adverse events were observed; however, 63 (17%) participants in the rifampicin group versus 39 (10%) in the placebo group had antibiotic or trial drug-modifying adverse events (p=0·004), and 24 (6%) versus six (2%) had drug interactions (p=0·0005). INTERPRETATION: Adjunctive rifampicin provided no overall benefit over standard antibiotic therapy in adults with S aureus bacteraemia. FUNDING: UK National Institute for Health Research Health Technology Assessment

Synthesis and Characterization of Phosphate Doped BaPr1-y(Y/Yb/Tm)yO3-δ

In this paper we examine the effects of doping phosphate into yttrium, ytterbium, and thulium doped BaPrO3. Through phosphate doping it is possible to achieve high levels of Y/Yb/Tm, and we show that it is possible to completely replace all the Pr with this co-doping strategy, albeit such phases contained small impurities. The samples were analysed through a combination of X-ray diffraction, TGA, Raman spectroscopy and conductivity measurements. Conductivity data indicated that these heavily Y/Yb/Tm doped samples, however, showed lower conductivities than reported for previously for low levels (10-20%) of Y/Yb doping. </p