Reducing the environmental impact of surgery on a global scale: systematic review and co-prioritization with healthcare workers in 132 countries

Abstract Background Healthcare cannot achieve net-zero carbon without addressing operating theatres. The aim of this study was to prioritize feasible interventions to reduce the environmental impact of operating theatres. Methods This study adopted a four-phase Delphi consensus co-prioritization methodology. In phase 1, a systematic review of published interventions and global consultation of perioperative healthcare professionals were used to longlist interventions. In phase 2, iterative thematic analysis consolidated comparable interventions into a shortlist. In phase 3, the shortlist was co-prioritized based on patient and clinician views on acceptability, feasibility, and safety. In phase 4, ranked lists of interventions were presented by their relevance to high-income countries and low–middle-income countries. Results In phase 1, 43 interventions were identified, which had low uptake in practice according to 3042 professionals globally. In phase 2, a shortlist of 15 intervention domains was generated. In phase 3, interventions were deemed acceptable for more than 90 per cent of patients except for reducing general anaesthesia (84 per cent) and re-sterilization of ‘single-use’ consumables (86 per cent). In phase 4, the top three shortlisted interventions for high-income countries were: introducing recycling; reducing use of anaesthetic gases; and appropriate clinical waste processing. In phase 4, the top three shortlisted interventions for low–middle-income countries were: introducing reusable surgical devices; reducing use of consumables; and reducing the use of general anaesthesia. Conclusion This is a step toward environmentally sustainable operating environments with actionable interventions applicable to both high– and low–middle–income countries

Enhancing aromatics and olefins yields in thermo-catalytic pyrolysis of LDPE over zeolites: Role of staged catalysis and acid site density of HZSM-5

The present work deals with the thermo-catalytic pyrolysis of LDPE (low-density polyethylene) in lab-scale one-and two-stage test rigs over HZSM-5 catalysts featuring different acid site densities. In the first part of this work, the influence of catalyst-to-feed ratio and temperature (in conjunction with the acid site density of HZSM-5) on the product distribution was studied with an aim to identify the optimum operating conditions for the enhanced production of aromatics and light olefins. For this purpose, one-stage thermo-catalytic pyrolysis was performed in which catalysts were mixed with LDPE pellets for in-situ catalysis. In the one-stage catalytic pyrolysis, the catalyst sample with the highest acid site density gave the highest concentration of aromatics (ca. 55%) in the pyrolysis oil with a mono-aromatics fraction of over 50% that consisted mainly of BTEX (benzene, toluene, ethylbenzene and xylenes) compounds. The highest C-2-C-4 olefins concentration (ca. 65%) in the pyrolysis gas was obtained when the sample with the lowest acid site density was used. In the two-stage catalytic pyrolysis (ex-situ catalysis), the concentration of aromatics in the pyrolysis oil reached over 77% with a mono-aromatics fraction of ca. 72% that contained mainly BTEX compounds, when the most acidic catalyst was used. When the catalyst with the lowest number of strong acid sites was employed, the high content of C-2-C-4 olefins in the pyrolysis gas remained almost independent of the reactor configuration. These findings might provide important new insights for the chemical recycling of plastic wastes.Web of Science314art. no. 12307

Chemical recycling of waste polypropylene via thermocatalytic pyrolysis over HZSM-5 catalysts

The present work deals with the chemical recycling of waste polypropylene viathermocatalytic pyrolysis over HZSM-5 zeolite catalysts. The main aim was tosystematically investigate the influence of reactor configuration, zeolite acidity,polypropylene wastes, obtained from different sources, as well as catalyst regener-ation on the product distribution. It was demonstrated that the reactor configura-tion and the acid site density of HZSM-5 catalysts strongly influence the productyields and distributions. The different types of polypropylene waste, on the otherhand, showed a comparatively small yet noticeable effect on the product distribu-tion. Moreover, it was demonstrated that the HZSM-5 catalysts exhibit goodregeneration capacity during regeneration-reaction cycles.Web of Science4661297128

Low yield of head CT in cirrhotic patients presenting with hepatic encephalopathy

Goals and background The utility of routine head CT (HCT) in hepatic encephalopathy (HE) evaluation is unclear. We investigated HCT yield in detecting acute intracranial abnormalities in cirrhotic patients presenting with HE.Study Retrospective review of cirrhotic patient encounters with HE between 2016 and 2018 at Beaumont Health, in Michigan was performed. A low-risk (LR) indication for HCT was defined as altered mental status (AMS), which included dizziness and generalised weakness. A high-risk (HR) indication was defined as trauma/fall, syncope, focal neurological deficits (FNDs) or headache. Descriptive statistics and univariate/multivariate analyses by logistic regression were performed using SPSS to identify HCT abnormality correlates.Results Five hundred twenty unique encounters were reviewed. Mean age was 63.4 (12.1) years, 162 (37.5%) had alcoholic cirrhosis and median Model for End-Stage Liver Disease (MELD)-score was 17 (13–23). LR indication was reported in 408 (78.5%) patients and FNDs reported in 24 (4.6%) patients. Only 13 (2.5%) patients were found to have an acute intracranial pathology (seven haemorrhagic stroke, two ischaemic stroke, four subdural haematoma). Aspirin use prior to presentation (aOR 4.6, 95% CI 1.1 to 19.2), and HR indication (aOR 7.3, 95% CI 2.3 to 23.8) were independent correlates of acute intracranial pathology on HCT. Age, sex, MELD-score, haemoglobin, platelet count, race and cirrhosis aetiology did not correlate with HCT abnormalities. Number needed to screen to identify one acute pathology was 14 in HR indications versus 82 for LR indications.Conclusion Routine HCTs in cirrhotic patients presenting with HE with AMS in the absence of history of trauma, headache, syncope, FNDs or aspirin use is of low diagnostic yield

Greening the esterification between isosorbide and acetic acid

This contribution deals with the investigation of greener conditions for the preparation of 2,5-diacetyl-isosorbide from the bio-based substances isosorbide and acetic acid. The influence of solvent, catalyst and reactant ratio on the course of the isosorbide conversion and selectivity to 2,5-diacetyl-isosorbide as well as to the intermediate 2-acetyl-isosorbide is examined. It was found that the conventionally used solvent toluene can be substituted by the greener solvent n-propyl acetate. Additionally, the homogeneous acid catalyst p-toluene sulfonic acid can be replaced by the heterogeneous catalyst Amberlyst-15, resulting in an easier isolation of the desired 2,5-diacetyl-isosorbide, this being an important precursor for the vasodilatory drug isosorbide-5-nitrate

Recent advances in the synthesis of hierarchically porous silica materials on the basis of porous glasses

The thermal phase separation and subsequent leaching of sodium borosilicate glasses is a well established route for the preparation of porous glasses exhibiting adjustable pore sizes in the range of 1 nm up to almost 1 μm as well as a very flexible geometric shape. The combination of this route with a large spectrum of synthesis strategies for the implementation of an additional pore system enables the preparation of hierarchically porous glass-based materials. This review covers a wide range of preparative routes for hierarchically porous silica materials starting from the sodium borosilicate glass with a special emphasis on the very recent developments in this versatile field of materials engineering

Comparative Study between Direct and Pseudomorphic Transformation of Rice Husk Ash into MFI-Type Zeolite

Pre-shaped mesoporous amorphous rice husk ash (RHA) and MCM-41 derived from RHA as a silica source were transformed into MFI-type zeolites using two different structure-directing agents. Tetrapropylammonium hydroxide (TPAOH) was utilized as an alkali source for silica dissolution and structure control during the direct transformation of RHA into zeolite. A monopropylamine (PA)-containing alkaline solution (NaOH) was used for the pseudomorphic transformation of RHA or MCM-41 into zeolite. The hydrothermal conversion of RHA or MCM-41 into MFI-type zeolites was investigated as a function of reaction time at 175 °C. With PA as template, the crystallization took place inside and on the outer surface of RHA or MCM-41 without losing the original shape of the initial silica sources, while TPAOH led to the formation of conventional MFI-type zeolite crystals due to the complete dissolution of RHA. The final products were characterized by X-ray diffraction, nitrogen adsorption, scanning electron microscopy, and optical emission spectroscopy

Cobalt mixed oxides deposited on the SiC open-cell foams for nitrous oxide decomposition

Supported Co3O4 and Co4MnAlOx mixed oxides were prepared by deposition on the SiC open-cell foams by wet impregnation and suspension methods and characterized by AAS, BET, XRD, SEM, TEM, TPR-H-2, XPS and nitrogen adsorption methods. Prepared supported catalysts as well as active phase Co3O4 and Co4MnAlOx in grain form prepared from parent solutions were tested for nitrous oxide decomposition. Catalytic activity of grain active phase was governed by methods of preparation; Co3O4 and Co4MnAlOx prepared by suspension method were significantly more active than those from solutions for impregnation method. Suspension method provided active phase with higher surface areas and sites with better reducibility, both of these factors contributed to higher N2O conversions. In contrast to this, N2O conversions over supported catalysts were dependent more on chemical composition of active phase than on method of preparation. Both catalysts containing Co4MnAlOx mixed oxide revealed higher conversion of N2O than catalysts containing Co3O4. STEM analysis of the most active Co4MnAlOx prepared by suspension method showed (i) segregation of Co3O4 nanocrystals of cuboctahedral shape containing (100) and (111) facets (this segregation was confirmed also by XPS and TPR-H-2) and (ii) Co-Mn-Al oxide nanoparticles with very small un-faceted grains assembled into elongated fiber-like agglomerates were observed by STEM.Web of Science255art. no. 11774