Production of hydrogen by methane dry reforming over ruthenium-nickel based catalysts deposited on Al2O3, MgAl2O4, and YSZ

In this work, monometallic (1 wt% of Ru or 5 wt% of Ni) and bimetallic catalysts (1 wt% Ru-5 wt.% Ni) deposited on alumina (Al2O3), magnesium aluminate spinel (MgAl2O4), and yttriastabilized zirconia (YSZ) were prepared by wet impregnation. The synthesis method of MgAl2O4 was optimized and a well crystallized phase with high specific surface area was obtained by using wet impregnation, as a simple and low cost route, at 800 °C for 2 h. The catalytic activity was compared at atmospheric pressure and 750 °C toward methane dry reforming (DRM) reaction with a molar ratio CH4/CO2 ¼ 1/1 and a Weight Hourly Space Velocity (WHSV) of 60.000 mL g-1.h-1. Catalytic activity classification was obtained as the following: Ni/MgAl2O4 > Ru-Ni/ Al2O3 > Ru-Ni/MgAl2O4 > Ru-Ni/YSZ > Ni/Al2O3 > Ni/YSZ > Ru/Al2O3 > Ru/YSZ » Ru/MgAl2O4. Between the different catalysts, 5 wt% Ni/MgAl2O4 catalyst exhibited excellent catalytic activity for DRM. Furthermore, this catalyst was found to be very stable without any deactivation after 50 h under reacting mixture with a low carbon formation rate (3.58 mgC/gcat/h). Such superior activity and stability of MgAl2O4 supported Ni catalyst is consistent with characterization results from BET, XRD, TPR, CO-pulse chemisorption and CHNS analysis. It can be due to a strong interaction between Ni and MgAl2O4 leading to theincorporation of Ni into the spinel lattice and the formation of oxygen vacancies offering a benefit for DRM reaction. Furthermore, it seems that the addition of ruthenium onto Ni/MgAl2O4 decreases the interaction between Ni and the spinel leading to a decrease in the catalyst performance. On the other side, the addition of ruthenium on Ni/Al2O3 leads to an increase in the catalyst stability and efficiency by inhibiting the formation of poorly active phase NiAl2O4 already observed in TPR

Production of hydrogen by methane dry reforming: A study on the effect of cerium and lanthanum on Ni/MgAl2O4 catalyst performance

Hydrogen production from dry reforming of methane (DRM) was investigated on different Nickel based catalysts deposited on MgAl2O4. MgAl2O4 spinel was prepared using Alumina supplied from different manufacturers (Sigma Aldrich, Alfa Aesar and Degussa) with low and high specific surface area. Moreover, the influence of different parameters on the catalytic activity on methane dry reforming was studied such as the effect of Ni content, the effect of commercial alumina and the effect of doping nickel with cerium and lanthanum. During this study, the catalytic activity was compared at atmospheric pressure at 750 °C during 4h than 650 °C during 4h toward methane dry reforming (DRM) reaction with a molar ratio CH4/CO2 =1/1 and a Weight Hourly Space Velocity (WHSV) of 60.000 mL.g-1.h-1. The results showed that among the different catalysts 1.5Ce-Ni5/MgAl2O4, synthesized with alumina from Alfa Aesar, exhibited the best catalytic activity for DRM. Furthermore, this catalyst showed the best performance during a stability tes at 600 °C for 24 h under reacting mixture with a low carbon formation rate (2.71 mgC/gcat/h). Such superior activity is consistent with characterization results from BET, XRD, SEM, TPR and TPO analysis. Furthermore, it seems that the addition of Cerium on Ni/MgAl2O4 leads to an increase in catalyst efficiency. It can be due to an effective active oxygen transfer due to the redox properties of CeO2, leading to the formation of oxygen vacancies offering a benefit for DRM reaction

Phlebitis risk varies by peripheral venous catheter site and increases after 96 hours: A large multi-centre prospective study

This multi-centre prospective field study evaluated whether peripheral venous catheter site of insertion influences the risk of catheter-related phlebitis. Potential predictors of phlebitis were also investigated. Background: Millions of patients worldwide use peripheral venous catheters, which frequently cause local complications including phlebitis, infection and obstruction. Although phlebitis predictors have been broadly investigated, uncertainties remain on the potential effect of cannulation anatomical site, duration and the appropriate time for catheter removal. Design: A prospective cohort design was carried out from January-June 2012. Methods: The clinical course of each patient who received a new peripheral venous catheter for any cause in five Italian hospitals was followed by trained nurses until catheter removal. The presence of phlebitis was assessed every 24 hours using the Visual Infusion Phlebitis score. Analyses were based upon multilevel mixed-effects regression. Results: The final sample consisted of 1498 patients. The average time for catheters in situ was 65·6 hours and 23·6% of the catheters were in place beyond 96 hours. Overall phlebitis incidence was 15·4%, 94·4% of which were grade 1. The likelihood of phlebitis independently increased with increasing catheter duration, being highest after 96 hours. Compared with patients with catheter placed in the dorsum of the hand (22·8% of the sample), those with the catheter located in the antecubital fossa (34·1%) or forearm were less likely to have a phlebitis of any grade. Conclusions: Antecubital fossa and forearm veins may be preferential sites for peripheral venous cannulation. Our results support Centers for Disease Control and Prevention recommendations to replace catheters in adults no later than 96 hours. A relevant proportion of healthcare personnel did not adhere to such guidelines - more attention to this issue is required

Variation in communication and family visiting policies in intensive care within and between countries during the Covid-19 pandemic: The COVISIT international survey

Background: During the COVID-19 pandemic, intensive care units (ICU) introduced restrictions to in-person family visiting to safeguard patients, healthcare personnel, and visitors. Methods: We conducted a web-based survey (March-July 2021) investigating ICU visiting practices before the pandemic, at peak COVID-19 ICU admissions, and at the time of survey response. We sought data on visiting policies and communication modes including use of virtual visiting (videoconferencing). Results: We obtained 667 valid responses representing ICUs in all continents. Before the pandemic, 20% (106/525) had unrestricted visiting hours; 6% (30/525) did not allow in-person visiting. At peak, 84% (558/667) did not allow in-person visiting for patients with COVID-19; 66% for patients without COVID-19. This proportion had decreased to 55% (369/667) at time of survey reporting. A government mandate to restrict hospital visiting was reported by 53% (354/646). Most ICUs (55%, 353/615) used regular telephone updates; 50% (306/667) used telephone for formal meetings and discussions regarding prognosis or end-of-life. Virtual visiting was available in 63% (418/667) at time of survey. Conclusions: Highly restrictive visiting policies were introduced at the initial pandemic peaks, were subsequently liberalized, but without returning to pre-pandemic practices. Telephone became the primary communication mode in most ICUs, supplemented with virtual visits

SARS-CoV-2 vaccination modelling for safe surgery to save lives: data from an international prospective cohort study

Background: Preoperative SARS-CoV-2 vaccination could support safer elective surgery. Vaccine numbers are limited so this study aimed to inform their prioritization by modelling. Methods: The primary outcome was the number needed to vaccinate (NNV) to prevent one COVID-19-related death in 1 year. NNVs were based on postoperative SARS-CoV-2 rates and mortality in an international cohort study (surgical patients), and community SARS-CoV-2 incidence and case fatality data (general population). NNV estimates were stratified by age (18-49, 50-69, 70 or more years) and type of surgery. Best- and worst-case scenarios were used to describe uncertainty. Results: NNVs were more favourable in surgical patients than the general population. The most favourable NNVs were in patients aged 70 years or more needing cancer surgery (351; best case 196, worst case 816) or non-cancer surgery (733; best case 407, worst case 1664). Both exceeded the NNV in the general population (1840; best case 1196, worst case 3066). NNVs for surgical patients remained favourable at a range of SARS-CoV-2 incidence rates in sensitivity analysis modelling. Globally, prioritizing preoperative vaccination of patients needing elective surgery ahead of the general population could prevent an additional 58 687 (best case 115 007, worst case 20 177) COVID-19-related deaths in 1 year. Conclusion: As global roll out of SARS-CoV-2 vaccination proceeds, patients needing elective surgery should be prioritized ahead of the general population