Desilicated NaY zeolites impregnated with magnesium as catalysts for glucose isomerisation into fructose

Acknowledgement This work was performed with financial support from EPSRC(UK) under grant EP/K014749/1. Solid-state NMR spectra were obtained at the EPSRC UK National Solid-state NMR Service at Durham.Peer reviewedPublisher PD

Micro- and mesoporous supports for CO2 methanation catalysts : a comparison between SBA-15, MCM-41 and USY zeolite

Mesoporous SBA-15 synthesized by two different methods and MCM-41 were used as supports for Ni and Ni-Ce catalysts applied in CO2 methanation reaction. The performances obtained for both materials were compared taking into account the differences in terms of textural properties, Ni species and reaction mechanism. Results were compared with the reported in the literature for a microporous USY zeolite. XRD, DRS UV–Vis, H2-TPR and TEM were used for the characterization of the samples. Catalytic tests were performed under the same conditions for all catalysts. Finally, FTIR Operando studies were carried out in order to establish differences from the mechanistically point of view as well as in terms of CO2 adsorption species for the different samples. Promising data was obtained with the Ni-based SBA-15 catalysts whatever the preparation method. Despite the greater Ni particles size, MCM-41 also reported interesting catalytic performances, so that presenting the highest TOF values among the catalysts studied. The good results obtained for the MCM-41 could be explained by the lower amount of non-reactive carbonyl species adsorbed on the Ni0 particles surface during the reaction as well as by the enhanced interaction between metal and support reflected in the calculated band gap values. All the results are comparable to the obtained using a HNaUSY zeolite with Si/Al = 2.8 as support. Cerium incorporation on Ni/mesoporous supports allowed enhancing the CO2 conversion, especially at lower temperatures, as already reported for the zeolite-based samples

Magnesium as promoter of CO2 methanation on Ni-based USY zeolites

CO2 methanation was studied over Ni–Mg–USY zeolite catalysts. Mg was added by incipient wetness impregnation and ion exchange. Whatever the Mg incorporation method used, Mg is able to improve the performance of the Ni-zeolite catalysts. Magnesium impregnation at lower contents (below 2.5%) over a 5%Ni/zeolite leads to an enhancement of the CO2 conversion into methane of 15% at 350–450 °C, probably due to the induced increase of the Ni particle dispersion, as well as to the possible activation of CO2 on the defects present on the MgO surface. At higher Mg contents, the stronger interaction between Ni and Mg oxides, leading to the formation of NiO–MgO solid solutions, seems to reduce the reducibility of the Ni species, decreasing the amount of nickel active sites available and thus the catalytic performance. Furthermore, important improvements of the catalytic performance (CO2 conversion and CH4 selectivity increased around 20% at 350–450 °C) were also found for the Mg-exchanged 5%Ni/zeolite. The results are comparable to those obtained by impregnation, but lower Mg contents are required. The enhanced activation of CO2 on Mg2+, the more dispersed Ni particles on the support, as well as the enhanced Ni reducibility when compared to the impregnated catalysts can explain the observed results. The beneficial effect of the Mg addition both by impregnation and ion exchange was also observed for samples containing higher amounts of Ni, the best sample remaining stable after 10 h under reaction conditions. Thus, Mg could be an interesting promoter for CO2 methanation over Ni-zeolite catalysts

Impact of opioid-free analgesia on pain severity and patient satisfaction after discharge from surgery: multispecialty, prospective cohort study in 25 countries

Background: Balancing opioid stewardship and the need for adequate analgesia following discharge after surgery is challenging. This study aimed to compare the outcomes for patients discharged with opioid versus opioid-free analgesia after common surgical procedures.Methods: This international, multicentre, prospective cohort study collected data from patients undergoing common acute and elective general surgical, urological, gynaecological, and orthopaedic procedures. The primary outcomes were patient-reported time in severe pain measured on a numerical analogue scale from 0 to 100% and patient-reported satisfaction with pain relief during the first week following discharge. Data were collected by in-hospital chart review and patient telephone interview 1 week after discharge.Results: The study recruited 4273 patients from 144 centres in 25 countries; 1311 patients (30.7%) were prescribed opioid analgesia at discharge. Patients reported being in severe pain for 10 (i.q.r. 1-30)% of the first week after discharge and rated satisfaction with analgesia as 90 (i.q.r. 80-100) of 100. After adjustment for confounders, opioid analgesia on discharge was independently associated with increased pain severity (risk ratio 1.52, 95% c.i. 1.31 to 1.76; P < 0.001) and re-presentation to healthcare providers owing to side-effects of medication (OR 2.38, 95% c.i. 1.36 to 4.17; P = 0.004), but not with satisfaction with analgesia (beta coefficient 0.92, 95% c.i. -1.52 to 3.36; P = 0.468) compared with opioid-free analgesia. Although opioid prescribing varied greatly between high-income and low- and middle-income countries, patient-reported outcomes did not.Conclusion: Opioid analgesia prescription on surgical discharge is associated with a higher risk of re-presentation owing to side-effects of medication and increased patient-reported pain, but not with changes in patient-reported satisfaction. Opioid-free discharge analgesia should be adopted routinely

El laboratorio y los derrames tuberculosos : (cito y sero-diagnóstico)

Tese presentada para optar ao grao de Doutor en Medicin