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

Micro- and Macromechanical Properties of a Composite with a Ternary PLA–PCL–TPS Matrix Reinforced with Short Fique Fibers

Biocomposites were prepared from a ternary matrix of polylactic acid (PLA), polycaprolactone (PCL), and thermoplastic starch (TPS) and reinforced with native fique fibers from southwestern Colombia. The influence of surface modification by alkalization of fique fibers on the interfacial properties of the biocomposite was studied using pull-out tests. Additionally, the effect of short fique fibers in three proportions (10%, 20%, and 30% (w/w)) on the tensile mechanical properties of the composite was evaluated. The experimental results indicated that the interfacial shear strength (IFSS) of the ternary matrix was predominantly influenced by PCL and characterized by the development of a weak interface that failed due to matrix yielding. Furthermore, the incorporation of short fique fibers increased the elastic modulus of the composite to values similar to those estimated with the Tsai–Pagano model. The alkalization treatment of the fique fibers improved the interface with the composite matrix, and this phenomenon was evidenced by the results of the micromechanical and tensile characterizations of the composite

Potential Uses of Musaceae Wastes: Case of Application in the Development of Bio-Based Composites

The Musaceae family has significant potential as a source of lignocellulosic fibres and starch from the plant’s bunches and pseudostems. These materials, which have traditionally been considered waste, can be used to produce fully bio-based composites to replace petroleum-derived synthetic plastics in some sectors such as packaging, the automotive industry, and implants. The fibres extracted from Musaceae have mechanical, thermal, and physicochemical properties that allow them to compete with other natural fibres such as sisal, henequen, fique, and jute, among others, which are currently used in the preparation of bio-based composites. Despite the potential use of Musaceae residues, there are currently not many records related to bio-based composites’ developments using starches, flours, and lignocellulosic fibres from banana and plantain pseudostems. In this sense, the present study focusses on the description of the Musaceae components and the review of experimental reports where both lignocellulosic fibre from banana pseudostem and flour and starch are used with different biodegradable and non-biodegradable matrices, specifying the types of surface modification, the processing techniques used, and the applications achieved

Physicochemical characterization of natural and acetylated thermoplastic cassava starch

Thermoplastic starch (TPS) was obtained from natural and acetylated cassava starch using a twin screw extruder and then conditioned at 25 ºC and 54 % of relative humidity. It was found that the crystallinity index, calculated as the ratio of the IR peaks at 1047 (crystalline phase) and 1022 cm¯¹ (amorphous phase), decreases due to the effect of a plasticization process. Also, as expected, SEM micrographs show that the plasticization process destroyed the starch granular structure almost completely and an amorphous mass was obtained. The TGA results indicated that the activation energy, Ea, was also reduced by the plasticization process. The acetylated TPS shows a decrease in Tg, in tensile strength and in the percentage of moisture absorption compared to natural TPS but a larger strain at the breaking point. This behavior suggests that the chemical modification reduces the secondary interactions between starch chains due to the substitution of the hydroxyl groups by acetates

Production and Modification of Cellulose Nanocrystals from Agave tequilana Weber Waste and Its Effect on the Melt Rheology of PLA

The production and surface modification of cellulose nanocrystals (CNC) from Agave tequilana Weber waste (ATW) and their effect on the melt rheology of PLA were investigated. For that, CNC were obtained from ATW residues by acid hydrolysis and grafted with 2-ethyl hexyl acrylate (2-EHA) to promote compatibility with nonpolar polymers, such as PLA. The morphology of CNC occurred as rods, spheres, and the so-called porous network observed by scanning electron microscopy (SEM) and electron transmission microscopy (TEM), and the crystallinity of the cellulose fibers was ~73% and increased up to ~94% for CNC followed by X-ray diffraction (XRD). The acid hydrolysis and alkali extraction process produce changes on the native cellulose type I from ATW bagasse resulting in a mixture of cellulose type I and II and was preserved after CNC isolation and surface grafting. Polymer grafting was assessed using Fourier-transform infrared spectroscopy (FTIR) and X-ray electron spectroscopy (XPS). Upon surface modification, the grafted CNC presented better thermal stability than CNC pristine evaluated by thermogravimetric analysis (TGA), and the surface energy of the CNC was decreased which could promote CNC dispersion within polymers. Both pristine and surface modified CNC were melt mixed with PLA to produce nanocomposites at different concentrations of CNC. Dynamic time sweep tests showed that the introduction of CNC and CNC/2-EHA decreased the complex viscosity of PLA due to polymer degradation during compounding

Physicochemical characterization of natural and acetylated thermoplastic cassava starch

Thermoplastic starch (TPS) was obtained from natural and acetylated cassava starch using a twin screw extruder and then con-ditioned at 25 ºC and 54 % of relative humidity. It was found that the crystallinity index, calculated as the ratio of the IR peaks at 1047 (crystalline phase) and 1022 cm-1 (amorphous phase), decreases due to the effect of a plasticization process. Also, as expected, SEM micrographs show that the plasticization process destroyed the starch granular structure almost completely and an amorphous mass was obtained. The TGA results indicated that the activation energy, Ea, was also reduced by the plasticization process. The acetylated TPS shows a decrease in Tg, in tensile strength and in the percentage of moisture absorption compared to natural TPS but a larger strain at the breaking point. This behavior suggests that the chemical modifi cation reduces the secondary interactions between starch chains due to the substitution of the hydroxyl groups by acetateAlmidón de Yuca natural y acetilado fueron plastificados empleando un extrusor de doble husillo y almacena-dos a 25 °C y 54 % de humedad relativa. El índice de cristalinidad, estimado como el cociente de las bandas de FTIR a 1047 (fase cristalina) y a 1022 cm-1 (fase amorfa) disminuyó en ambos almidones debido al proceso de plastificación. Mediante las micro-grafías de SEM se pudo observar que el proceso de plastificación destruyó casi por completo la estructura granular de los almidones. Los resultados de TGA mostraron que la energía de activación, Ea, disminuyó con el proceso de plastificación. Por otra parte se encontró que el almidón termoplástico acetilado presentó una Tg, absorción de agua y resistencia a tensión menores en comparación con el almidón termoplástico natural, mientras que su elongación a la ruptura fue mayor. Este comportamiento sugirió que la esterificación de los grupos hidroxilos del almidón natural redujeron las interacciones entre las cadenas del almidón plastificad

Effect of Cellulose and Cellulose Nanocrystal Contents on the Biodegradation, under Composting Conditions, of Hierarchical PLA Biocomposites

In this work, the effect of microfibrillated cellulose (MFC) and cellulose nanocrystals (CNCs) on the biodegradation, under composting conditions, of hierarchical PLA biocomposites (HBCs) was studied using a full 22 factorial experimental design. The HBCs were prepared by extrusion processing and were composted for 180 days. At certain time intervals, the specimens were removed from the compost for their chemical, thermal and morphological characterizations. An ANOVA analysis was carried out at different composting times to study MFC and CNCs’ effects on biodegradation. The specimen’s mass loss and molecular weight loss were selected as independent variables. The results show that the presence of MFC enhances the PLA biodegradation, while with CNCs it decreases. However, when both cellulosic fibers are present, a synergistic effect was evident—i.e., in the presence of the MFC, the inclusion of the CNCs accelerates the HBCs biodegradation. Analysis of the ANOVA results confirms the relevance of the synergistic role between both cellulosic fibers over the HBC biodegradation under composting conditions. The results also suggest that during the first 90 days of incubation, the hydrolytic PLA degradation prevails, whereas, beyond that, the enzymatic microbial biodegradation dominates. The SEM results show MFC’s presence enhances the surface biodeterioration to a greater extent than the CNCs and that their simultaneous presence enhances PLA biodegradation. The SEM results also indicate that the biodegradation process begins from hydrophilic cellulosic fibers and promotes PLA biodegradation

Interfacial Shear Strength Evaluation of Pinewood Residue/High-Density Polyethylene Composites Exposed to UV Radiation and Moisture Absorption-Desorption Cycles

In outdoor applications, the mechanical performance of wood-plastic composites (WPCs) is affected by UV radiation, facilitating moisture intake and damaging the wood-polymer interfacial region. The purpose of this study was to evaluate the effect of moisture absorption-desorption cycles (MADCs), and the exposure to UV radiation on the interfacial shear strength (IFSS) of WPCs with 40% pinewood residue and 60% high-density polyethylene. One of the WPCs incorporated 5% coupling agent (CA) with respect to wood content. The IFSS was evaluated following the Iosipescu test method. The specimens were exposed to UV radiation using an accelerated weathering test device and subsequently subjected to four MADCs. Characterization was also performed by scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR). The absorption and desorption of moisture was slower in non-UV-irradiated WPCs, particularly in those with the CA. The UV radiation did not significantly contribute to the loss of the IFSS. Statistically, the CA had a favorable effect on the IFSS. Exposure of the samples to MADCs contributed to reduce the IFSS. The FTIR showed lignin degradation and the occurrence of hydrolysis reactions after exposure to MADCs. SEM confirmed that UV radiation did not significantly affect the IFSS