•SACS/DES1 is cheaper, eco-friendlier, and efficient catalytic system.•The HMF was obtained in 67% yield and 100% selectivity.•The simple isolation of HMF from DES was performed by phase ...extraction.•SACS/DES1 could be recycled with a little decrease in reactivity.
Our findings could have an impact on the synthesis of HMF and the rational design of deep eutectic solvents (DES) for liquid‐phase separations of HMF in biomass processing. Brønsted acidic sites in the case of sulfonated amorphous carbon–silica (SACS) led to excellent selectivity in the dehydration of fructose in deep eutectic solvents. The deep eutectic solvents were found to play a crucial role to suppress the formation of undesired products and make the work-up separation of HMF easier. The combination of amorphous carbon with deep eutectic solvent allowed to conduct a transformation of fructose to HMF with 67% yield and 100% selectivity towards HMF at 110 °C in 4 h. The excellent selectivity, work-up simplification, and recyclable catalytic system provide a cost-effective strategy for the synthesis of HMF.
•Fibre length and volume fraction are demonstrated to influence mechanical properties of printed concrete.•Sufficient fibre volume and length is required to increase the flexural resistance.•3D ...printed concrete demonstrates anisotropic properties regardless of printing strategy.•Microscale structure of hardened concrete is visualised, and porosity is quantified by X-ray micro-CT.•Porosity content of printed concrete is dependent on fibre volume fractions.
Mechanical properties of high-performance printing concrete reinforced with steel fibres with different lengths (3 and 6 mm) at different fibre volume contents (0.25%, 0.5%, 0.75% and 1%) are investigated. The experimental results substantiate that critical length and volume fraction of fibres, particularly 0.75% and 1% steel fibres of 6 mm length, in conjunction with fibre alignment, are of major importance for generating fibre bridging mechanism to improve flexural performance. As a result, enhanced load-carrying capacity, deflection hardening behaviour and less brittle failure can be achieved in printed specimens tested in a specific direction. Compressive and flexural strengths of printed concrete are in a range of 70-111 MPa and 6–15 MPa compared with the cast control of 90–113 MPa and 11–14 MPa, respectively. Results from micro-computed tomography scanning on hardened concrete without fibres reveal that the high-quality printed concrete has lower pore content, which is 8.8% compared with 9.8% and 11.4% in the cast and low-quality printed samples, respectively. It also shows that more than 90% of extruded fibres align within 0°-30° from the filament orientation.
In response to the rapid spread of coronavirus disease-2019 (COVID-19) within and across countries and the need to protect public health, governments worldwide introduced unprecedented measures such ...as restricted road and air travel and reduced human mobility in 2020. The curtailment of personal travel and economic activity provided a unique opportunity for researchers to assess the interplay between anthropogenic emissions of primary air pollutants, their physical transport, chemical transformation, ultimate fate and potential health impacts. In general, reductions in the atmospheric levels of outdoor air pollutants such as particulate matter (PM), nitrogen dioxide (NO2), carbon monoxide (CO), sulfur dioxide (SO2), and volatile organic compounds (VOCs) were observed in many countries during the lockdowns. However, the levels of ozone (O3), a secondary air pollutant linked to asthma and respiratory ailments, and secondary PM were frequently reported to remain unchanged or even increase. An increase in O3 can enhance the formation of secondary PM2.5, especially secondary organic aerosols, through the atmospheric oxidation of VOCs. Given that the gaseous precursors of O3 (VOCs and NOx) are also involved in the formation of secondary PM2.5, an integrated control strategy should focus on reducing the emission of the common precursors for the co-mitigation of PM2.5 and O3 with an emphasis on their complex photochemical interactions. Compared to outdoor air quality, comprehensive investigations of indoor air quality (IAQ) are relatively sparse. People spend more than 80% of their time indoors with exposure to air pollutants of both outdoor and indoor origins. Consequently, an integrated assessment of exposure to air pollutants in both outdoor and indoor microenvironments is needed for effective urban air quality management and for mitigation of health risk. To provide further insights into air quality, we do a critical review of scientific articles, published from January 2020 to December 2020 across the globe. Finally, we discuss policy implications of our review in the context of global air quality improvement.
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•We studied the effects of the implementation of lockdown on air quality.•Reduction in primary air pollutants was observed in most cities during lockdowns.•Secondary PM and O3 increased in some cities under favorable weather conditions.•Exposure to high levels of PM can aggravate the health status of COVID-19 patients.•Indoor air quality assessment merits a serious consideration during lockdowns.
Gradual and localised changes in mechanical properties can be achieved by functionally graded cellular structures with the aim to improve structural performance. Gyroid belongs to a class of cellular ...structures that naturally inspired continuous non-self-intersecting surfaces with controllable mechanical properties. In this work, dynamic compression on functionally graded gyroid and sandwich composite panels constructed from functionally graded gyroid core and metallic facets are numerically investigated and compared to evaluate the dynamic behaviours when subjected to extreme loadings. The Finite Element Analysis (FEA) is employed to investigate the deformation behaviours of proposed structures considering the rate-dependent properties, elastoplastic response and nonlinear contact. The Johnson-Cook model is utilised to capture the rate-dependent dynamic responses of the gyroid panels. The numerical model is then validated with experimental results under quasi-static compression. Due to the symmetry, only a quarter of the gyroid panel is modelled using shell elements, which offers significantly reduction in computational cost. Parametric studies are conducted to demonstrate the influences of different functionally graded cores on the blast resistances of gyroid composite panels. Reaction forces and critical stress extracted from underneath protected structure are assessed. Fuctionally graded gyroid sandwich structures clearly demonstrate unique dynamic crushing responses, impact energy mitigation & dissipation mechanisms, which leads to enhancement of the blast resistance.
Fused deposition modelling (FDM) is one of the fastest-growing additive manufacturing methods used in printing fibre-reinforced composites (FRC). The performances of the resulting printed parts are ...limited compared to those by other manufacturing methods due to their inherent defects. Hence, the effort to develop treatment methods to overcome these drawbacks has accelerated during the past few years. The main focus of this study is to review the impact of those defects on the mechanical performance of FRC and therefore to discuss the available treatment methods to eliminate or minimize them in order to enhance the functional properties of the printed parts. As FRC is a combination of polymer matrix material and continuous or short reinforcing fibres, this review will thoroughly discuss both thermoplastic polymers and FRCs printed via FDM technology, including the effect of printing parameters such as layer thickness, infill pattern, raster angle and fibre orientation. The most common defects on printed parts, in particular, the void formation, surface roughness and poor bonding between fibre and matrix, are explored. An inclusive discussion on the effectiveness of chemical, laser, heat and ultrasound treatments to minimize these drawbacks is provided by this review.
Exosomes are small extracellular vesicles with diameters of 30-150 nm. In both physiological and pathological conditions, nearly all types of cells can release exosomes, which play important roles in ...cell communication and epigenetic regulation by transporting crucial protein and genetic materials such as miRNA, mRNA, and DNA. Consequently, exosome-based disease diagnosis and therapeutic methods have been intensively investigated. However, as in any natural science field, the in-depth investigation of exosomes relies heavily on technological advances. Historically, the two main technical hindrances that have restricted the basic and applied researches of exosomes include, first, how to simplify the extraction and improve the yield of exosomes and, second, how to effectively distinguish exosomes from other extracellular vesicles, especially functional microvesicles. Over the past few decades, although a standardized exosome isolation method has still not become available, a number of techniques have been established through exploration of the biochemical and physicochemical features of exosomes. In this work, by comprehensively analyzing the progresses in exosome separation strategies, we provide a panoramic view of current exosome isolation techniques, providing perspectives toward the development of novel approaches for high-efficient exosome isolation from various types of biological matrices. In addition, from the perspective of exosome-based diagnosis and therapeutics, we emphasize the issue of quantitative exosome and microvesicle separation.
Triply periodic minimal surfaces are cellular structures that naturally inspired continuous non-self-intersecting surfaces similar to bone microstructure with controllable mechanical properties. In ...this work, sandwich composite panels constructed from four different types of TMPS unit cells and metallic facets are numerically investigated and compared to evaluate the dynamic behaviours when subjected to extreme loadings. The finite element analysis is utilised to simulate the deformation of proposed structures considering the rate-dependent properties, elastoplastic response and nonlinear contact. The Johnson–Cook material model is implemented to capture the transient responses of the four TPMS panels under high strain-rate loadings. The numerical model is validated with a two-dimensional analytical one to reveal the static and dynamic crushing behaviors. Only a quarter of the sandwich panel is simulated using shell elements thanks to the symmetry, which significantly reduces the computational cost. A series of parametric studies are conducted to demonstrate the influences of different design parameters on the blast resistances of triply periodic minimal surface composite panels. Reaction forces and critical stresses extracted from underneath protected structure are assessed for various key parameters, including triply periodic minimal surface type, thickness and number of layers. The four TPMS sandwich structures clearly demonstrate unique dynamic crushing responses, impact energy mitigation and dissipation mechanisms, which leads to enhancement of the blast resistance.
Targeted exosomal delivery systems for precision nanomedicine attract wide interest across areas of molecular cell biology, pharmaceutical sciences, and nanoengineering. Exosomes are naturally ...derived 50–150 nm nanovesicles that play important roles in cell‐to‐cell and/or cell‐to‐tissue communications and cross‐species communication. Exosomes are also a promising class of novel drug delivery vehicles owing to their ability to shield their payload from chemical and enzymatic degradations as well as to evade recognition by and subsequent removal by the immune system. Combined with a new class of affinity ligands known as aptamers or chemical antibodies, molecularly targeted exosomes are poised to become the next generation of smartly engineered nanovesicles for precision medicine. Here, recent advances in targeted exosomal delivery systems engineered by aptamer for future strategies to promote human health using this class of human‐derived nanovesicles are summarized.
Recent advances in research and development of aptamer‐guided exosomes as a new nanoengineering strategy to achieve targeted drug delivery using bio‐nanoparticles highlight a promising next generation of targeted drug delivery systems. Cross‐fertilization between areas of exosomes and aptamers in both preclinical translational studies predicts a bright future for aptamer‐guided exosomal delivery in precision nanomedicine.
Smoke haze episodes, resulting from uncontrolled biomass burning (BB) including forest and peat fires, continue to occur in Southeast Asia (SEA), affecting air quality, atmospheric visibility, ...climate, ecosystems, hydrologic cycle and human health. The pollutant of major concern in smoke haze is airborne particulate matter (PM). A number of fundamental laboratory, field and modeling studies have been conducted in SEA from 2010 to 2020 to investigate potential environmental and health impacts of BB-induced PM. The goal of this review is to bring together the most recent developments in our understanding of various aspects of BB-derived PM based on 127 research articles published from 2010 to 2020, which have not been conveyed in previous reviews. Specifically, this paper discusses the physical, chemical, toxicological and radiative properties of BB-derived PM. It also provides insights into the environmental and health impacts of BB-derived PM, summarizes the approaches taken to do the source apportionment of PM during BB events and discusses the mitigation of exposure to BB-derived PM. Suggestions for future research priorities are outlined. Policies needed to prevent future BB events in the SEA region are highlighted.
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•Emission of biomass burning-derived particulate matter in Southeast Asia.•Physicochemical properties and health impacts of BB-derived PM.•Environmental impacts of BB-derived PM.•Source identification and source apportionment of BB-derived PM.•Future research directions for BB-related environmental and health issues.
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