Burnout among surgeons before and during the SARS-CoV-2 pandemic: an international survey

Background: SARS-CoV-2 pandemic has had many significant impacts within the surgical realm, and surgeons have been obligated to reconsider almost every aspect of daily clinical practice. Methods: This is a cross-sectional study reported in compliance with the CHERRIES guidelines and conducted through an online platform from June 14th to July 15th, 2020. The primary outcome was the burden of burnout during the pandemic indicated by the validated Shirom-Melamed Burnout Measure. Results: Nine hundred fifty-four surgeons completed the survey. The median length of practice was 10 years; 78.2% included were male with a median age of 37 years old, 39.5% were consultants, 68.9% were general surgeons, and 55.7% were affiliated with an academic institution. Overall, there was a significant increase in the mean burnout score during the pandemic; longer years of practice and older age were significantly associated with less burnout. There were significant reductions in the median number of outpatient visits, operated cases, on-call hours, emergency visits, and research work, so, 48.2% of respondents felt that the training resources were insufficient. The majority (81.3%) of respondents reported that their hospitals were included in the management of COVID-19, 66.5% felt their roles had been minimized; 41% were asked to assist in non-surgical medical practices, and 37.6% of respondents were included in COVID-19 management. Conclusions: There was a significant burnout among trainees. Almost all aspects of clinical and research activities were affected with a significant reduction in the volume of research, outpatient clinic visits, surgical procedures, on-call hours, and emergency cases hindering the training. Trial registration: The study was registered on clicaltrials.gov "NCT04433286" on 16/06/2020

Flame Propagation In Premixed Mixtures Of Liquid Biofuels

There is a great potential for biofuels in automotive applications because they show advantages in mitigating greenhouse-gases, improving air quality, and reducing our dependence of fossil fuels. Ketones are new class of biofuels produced from endophytic conversion of cellulose. 2,4-Dimethyl-3-pentanone (DIPK) is a promising ketone for automotive applications. In this study, the laminar burning velocity (LBV) of DIPK was investigated in a spherical combustion chamber at initial T=120°C and various initial pressures using two ignition (laser and spark) techniques. Both constant pressure and constant volume approaches were used to derive the LBV values. The flame stability was assessed based on Markstein length, linear, and nonlinear extrapolation methods. The extended LBV values along one isentrope in constant volume method, helps in obtaining LBV values in a high pressure and temperature environment similar to automotive engines. Current data can be compared to the predictions of recent DIPK chemical kinetic mechanisms

Laminar Burning Velocity Measurements In Dipk-An Advanced Biofuel

The biofuel and engine co-development framework was initiated at Sandia National Labs. Here, the synthetic biologists develop and engineer a new platform for drop-in fuel production from lignocellulosic biomass, using several endophytic fungi. Hence this process has the potential advantage that expensive pretreatment and fuel refining stages can be optimized thereby allowing scalability and cost reduction; two major considerations for widespread biofuel utilization. Large concentrations of ketones along with other volatile organic compounds were produced by fungi grown over switchgrass media. The combustion and emission properties of these new large ketones are poorly known. Therefore, fundamental measurements of representative molecules are needed to provide feedback on their desirability in advanced combustion engines (e.g., HCCI: homogeneous charge compression ignition engines) and their impact on emissions, as well as other combustion devices such as micro-combustors. 2,4-Dimethyl-3-pentanone, also known as diisopropyl ketone (DIPK), is a promising candidate biofuel for automotive applications produced by the fungal conversion process. Laminar burning velocity (LBV) is an important fundamental property of a fuel/air mixture and it depends on the composition, temperature, and pressure. Therefore, the knowledge of the dependence of the laminar burning velocity on above mentioned parameters can be used to design advanced engines as it can affect efficiency and heat release rates. We provide LBV measurements for DIPK, using the University of Central Florida (UCF) spherical flame chamber connected to a modified spark plug. Both pressure and direct flame visualization (shadowgraph) were utilized to ensure that the flame is spherical and stable (no cellular structure was observed within the flame) in order to provide reliable results with the constant volume approach. LBV measurements were also performed in iso-octane (C8H18), a relatively well characterized fuel, in order to validate our facility and measurement technique. The LBV results of C8H18/air and DIPK/air mixtures are compared with several oxygenated fuels in the literature and numerical values predicted by two chemical kinetic mechanisms

Laminar Burning Velocity Measurements in DIPK-An Advanced Biofuel

The biofuel and engine co-development framework was initiated at Sandia National Labs. Here, the synthetic biologists develop and engineer a new platform for drop-in fuel production from lignocellulosic biomass, using several endophytic fungi. Hence this process has the potential advantage that expensive pretreatment and fuel refining stages can be optimized thereby allowing scalability and cost reduction; two major considerations for widespread biofuel utilization. Large concentrations of ketones along with other volatile organic compounds were produced by fungi grown over switchgrass media. The combustion and emission properties of these new large ketones are poorly known. Therefore, fundamental measurements of representative molecules are needed to provide feedback on their desirability in advanced combustion engines (e.g., HCCI: homogeneous charge compression ignition engines) and their impact on emissions, as well as other combustion devices such as micro-combustors. 2,4-Dimethyl-3-pentanone, also known as diisopropyl ketone (DIPK), is a promising candidate biofuel for automotive applications produced by the fungal conversion process. Laminar burning velocity (LBV) is an important fundamental property of a fuel/air mixture and it depends on the composition, temperature, and pressure. Therefore, the knowledge of the dependence of the laminar burning velocity on above mentioned parameters can be used to design advanced engines as it can affect efficiency and heat release rates. We provide LBV measurements for DIPK, using the University of Central Florida (UCF) spherical flame chamber connected to a modified spark plug. Both pressure and direct flame visualization (shadowgraph) were utilized to ensure that the flame is spherical and stable (no cellular structure was observed within the flame) in order to provide reliable results with the constant volume approach. LBV measurements were also performed in iso-octane (C8H18), a relatively well characterized fuel, in order to validate our facility and measurement technique. The LBV results of C8H18/air and DIPK/air mixtures are compared with several oxygenated fuels in the literature and numerical values predicted by two chemical kinetic mechanisms

Electrochemical Hydrogen Evolution Reaction Evaluation of CoNi(Cr/V) Medium-Entropy Alloys in an Acidic Environment

Developing nonprecious metal-based electrocatalysts with outstanding performance has been the focal point of the scientific community for the past decade. Multiprinciple element medium- and high-entropy alloys have recently been known to exhibit a range of superior mechanical, physical, electrocatalytic, and anticorrosive properties, which are superior to traditional alloys. In this study, the electrocatalytic properties of equiatomic single-phase medium-entropy alloy electrodes with equiatomic compositions CoNiCr, CoNiV, and CoNi(Cr/V) are investigated for the hydrogen evolution reaction in 0.5 M H2SO4 at room temperature. Electrochemical measurements revealed operational overpotentials of 50 and 228 mV at current densities of 10 and 100 mA/cm2 with a Tafel slope of 46 mV/dec for the CoNi(Cr/V) alloy, while CoNiCr and CoNiV exhibited Tafel slopes of 78 and 82 mV/dec, respectively. The long-term durability of all specimens in the acidic phase was further tested at room temperature using cyclic voltammetry degradation and chronoamperometry methods, and it was found that all samples exhibited good stability with a shift in overpotential of just 6 mV@50 mA/cm2 after 2000 cycles and stable multistep current density values for 20 h. X-ray photoelectron spectroscopy analysis showed an increase in the surface oxidation number of Ni and Co through Cr and V doping, which is in agreement with the higher electrocatalytic activity of the CoNi(Cr/V) alloy. The spin-polarized first-principles calculations within the context of the plane wave self-consistent field method were performed to evaluate the mechanism of electrochemical experimental results

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