The increase in strength usually accompanies by the sacrifice of ductility in the composites. This work proposed a strategy of design and synthesis of in-situ TiB2 particles to effectively tailor the ...microstructures and to enhance the mechanical performance of Al–Si-based composites. The tuning mechanisms for size and morphology of TiB2 particles were investigated by combustion synthesis in the Al–Ti–B reaction system. The nano/submicron-sized TiB2 particles with desirable morphology were then specially selected to construct high-performance Al–Si-based composites. Thanks to the strong interface bonding with a low crystallographic mismatch, TiB2 particles significantly refined the primary α-Al dendrites, eutectic Si and θ’ precipitates in the composites, which were 79.2%, 51.9% and 37.6% respectively smaller than those of the matrix. Numerical modeling results suggested that submicron-sized TiB2 particles were more likely to be engulfed or serve as heterogeneous sites while nano-sized TiB2 particles would be repulsed to the solid/liquid interface to physically restrict the growth of α-Al dendrites. The strength-ductility trade-off dilemma was broken therefore superior mechanical properties were obtained in the composites. This work provides a novel perspective for manipulating Al–Si-based alloys in terms of avoiding poisoning and achieving microstructural refinement and outstanding strength-ductility synergy.
•Novel TiB2 particles were designed and synthesized to enhance the performance of Al–Si-based composites.•The size and morphology tuning mechanisms of in-situ TiB2 particles are revealed in the Al–Ti–B reaction system.•Nano/submicron-sized TiB2 particles exert strong interface bonding and low crystallographic mismatch with Al–Si matrix.•By optimizing the spatial distribution of TiB2 particles, composites outstanding strength-ductility synergy are achieved.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Monoclonal antibodies represent important weapons in our arsenal to against the COVID-19 pandemic. However, this potential is severely limited by the time-consuming process of developing effective ...antibodies and the relative high cost of manufacturing. Herein, we present a rapid and cost-effective lipid nanoparticle (LNP) encapsulated-mRNA platform for in vivo delivery of SARS-CoV-2 neutralization antibodies. Two mRNAs encoding the light and heavy chains of a potent SARS-CoV-2 neutralizing antibody HB27, which is currently being evaluated in clinical trials, were encapsulated into clinical grade LNP formulations (named as mRNA-HB27-LNP). In vivo characterization demonstrated that intravenous administration of mRNA-HB27-LNP in mice resulted in a longer circulating half-life compared with the original HB27 antibody in protein format. More importantly, a single prophylactic administration of mRNA-HB27-LNP provided protection against SARS-CoV-2 challenge in mice at 1, 7 and even 63 days post administration. In a close contact transmission model, prophylactic administration of mRNA-HB27-LNP prevented SARS-CoV-2 infection between hamsters in a dose-dependent manner. Overall, our results demonstrate a superior long-term protection against SARS-CoV-2 conferred by a single administration of this unique mRNA antibody, highlighting the potential of this universal platform for antibody-based disease prevention and therapy against COVID-19 as well as a variety of other infectious diseases.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Plasma medicine is a rapidly growing multidisciplinary field. Recently, experimental observations have shown that plasma‐activated oil (PAO) with high reactive activity can effectively promote wound ...healing. In this study, a reactive molecular dynamic (MD) simulation is performed to investigate the interactions of reactive oxygen species (ROS), such as O, OH, and O3 produced in atmospheric plasmas, and fatty acids in vegetable oils with the ReaxFF field. The reaction processes of the chemical bond breaking and formation of fatty acids upon impact by the ROS are deeply explored. The simulation shows that the reactions typically start with the H ion from fatty acids, then often resulting in the formation of double C═C bonds or conjugated double bonds. The insertion of functional groups, such as aldehyde and alcohol groups, and the detachment of the carboxyl group are also observed from the simulation. Based on the computational data the final products in PAO upon impact of ROS are given. Moreover, the dose effects of ROS on the oxidation processes are explored by changing the number of ROS in the simulation box. Usually, by increasing the number of ROS in the simulation, more reactive groups are generated in PAO, which are consistent with the experimental observation. This study unveils the formation and breaking of chemical bonds and the production of new reactive groups, which enables us to deeply understand the mechanisms of plasma pharmacy and plasma medicine.
Recently, experimental observations have shown that Plasma Activated Oil (PAO), can effectively promote wound healing, which provides a typical example of plasma pharmacy. In this paper, a reactive molecular dynamic (MD) simulation is performed to investigate the interactions of atmospheric plasmas and fatty acids in vegetable oils. The simulation reveals the reaction processes of breaking and formation of chemical bonds, especially the fragmentation of fatty acid chain upon the impact of O3 molecules, then summarizes the new reactive groups in PAO and the final products, which are consistent with the experimental observation. This study could effectively enhance the understanding of plasma pharmacy and plasma medicine.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Tuning solidification microstructure remains a grand challenge for ceramic particles reinforced Al-Si based composites due to adverse interactions between ceramic particles and Si-containing melts. ...This work proposed a novel in-situ synthesis strategy of designing master alloys decorated with well-dispersed TiCxNy and TiB2 particles to synergistically optimize the Al-Si based composites. By adjusting the reactant contents and ratios, near-spherical nano-sized TiCxNy particles and hexagonal submicron-sized TiB2 particles were obtained in as-synthesized Al-(TiCxNy-TiB2)p master alloys. The effects of this pre-dispersed agent on solidification kinetics, microstructure features and mechanical performance evolution of the Al-10Si-2Mg composites were investigated in detail. TiCxNy-TiB2 particles could trigger the heterogeneous nucleation of primary α-Al crystals, and the growth-restricting effects also contributed to grain refinement, which finally accounted for the enhancement in both strength and ductility. This work is expected to provide new guidance for selection of reinforcing particles and synergistic optimization of the solidification microstructure and performance.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Structural principles underlying the composition and synergistic mechanisms of protective monoclonal antibody cocktails are poorly defined. Here, we exploited antibody cooperativity to develop a ...therapeutic antibody cocktail against SARS-CoV-2. On the basis of our previously identified humanized cross-neutralizing antibody H014, we systematically analyzed a fully human naive antibody library and rationally identified a potent neutralizing antibody partner, P17, which confers effective protection in animal model. Cryo-EM studies dissected the nature of the P17 epitope, which is SARS-CoV-2 specific and distinctly different from that of H014. High-resolution structure of the SARS-CoV-2 spike in complex with H014 and P17, together with functional investigations revealed that in a two-antibody cocktail, synergistic neutralization was achieved by S1 shielding and conformational locking, thereby blocking receptor attachment and viral membrane fusion, conferring high potency as well as robustness against viral mutation escape. Furthermore, cluster analysis identified a hypothetical 3rd antibody partner for further reinforcing the cocktail as pan-SARS-CoVs therapeutics.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Comprehensive Summary
Molecular scaffolds endowed with all‐carbon quaternary stereocenter are ubiquitous in natural products and significant bioactive molecules. However, efficient construction of ...this type of structure units is full of challenge due to their congested chemical environment. Herein, we report a new gold(I) self‐relay catalysis merging 3,3‐sigmatropic rearrangement/Nazarov cyclization with allylic alkylation starting from 1,3‐enyne acetates and allylic alcohols, producing a wide range of synthetically important allyl cyclopentenones with an all‐carbon quaternary stereocenter in good yields under mild conditions. This protocol demonstrates the precise control of regioselectivity, high functional group tolerance of substrates and the low loading of gold catalyst without inert atmosphere protection, providing a catalytic and efficient entry to all‐carbon quaternary stereocenters
A new gold(I) self‐relay catalysis merging 3,3‐sigmatropic rearrangement/Nazarov cyclization with allylic alkylation starting from 1,3‐enyne acetates and allylic alcohols is reported, producing a wide range of synthetically important allyl cyclopentenones with an all‐carbon quaternary stereocenter in good yields under mild conditions.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Al–Zn–Mg–Cu alloys that are prone to segregation and hot cracks always encounter difficulty in manufacturing large-size workpiece with desirable strength-plasticity synergy, especially when the ...tonnage of the extruder exceeds 6000 tons. This work puts forward a novel idea to address this challenge by joining extruded profiles of Al–Zn–Mg–Cu-based composite reinforced by trace in-situ TiC–TiB2 nanoparticles through friction stir welding (FSW). The extruded profiles of Al–Zn–Mg–Cu-based composite along transverse direction (TD) achieved superior yield strength (σY) of 827 MPa and large plastic strain (εp) of 10.2%. The σY of FSW-ed joint along TD reached 847 MPa, and the εp was maintained at 2.8%. It was found that trace nanoparticles can weaken the grain boundary segregation of the composite ingot significantly, effectively avoiding the hot cracking that may occur during hot extrusion and FSW. In extruded profiles, nanoparticles promoted the nucleation of η′ precipitates, promoted the dislocation multiplication, and increased the proportions of low-angle grain boundaries (LAGBs) within 2°–15° and high-angle grain boundaries (HAGBs), thereby enhancing the strength. Meanwhile, nanoparticles increased the density of LAGBs and facilitated the precipitation of Guinier–Preston (GP) zones, which facilitated to maintain high plasticity of the extruded profiles of composite. Additionally, nanoparticles can effectively inhibit the abnormal grain growth in nugget zone (NZ) during post-weld heat treatment (PWHT), which strengthened the FSW-ed joint. This work elaborated the multiscale microstructure evolution mechanisms, offering guidance to fabricate Al–Zn–Mg–Cu workpieces with infinitely extensive size as required in actual manufacturing and fantastic mechanical performances.
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•Trace in-situ TiC–TiB2 enhanced performance of large-size Al–Zn–Mg–Cu composite.•TiC–TiB2 optimized segregation, recrystallization and precipitation behavior.•TiC–TiB2 inhibited the abnormal grain growth during post-weld heat treatment.•Microstructure evolution and performance improvement mechanisms were revealed.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
A new and green route to skeletally diverse oxo-heterocyclic architectures such as pyrano3,4-cchromen-2-ones and pyrano3,4-cquinolin-2-ones is reported via an unprecedented photocatalytic ...Kharasch-type cyclization/1,5-(SN″)-substitution/elimination/6π-electrocyclization/double nucleophilic substitution cascade starting from easily available heteroatom-linked 1,7-diynes and low-cost CBrCl3. During this reaction process, the full scission of carbon–halogen bonds of BrCCl3 was realized to directly build two new rings, including a lactone scaffold, using H2O as the oxygen source of the ester group.
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IJS, KILJ, NUK, PNG, UL, UM
•Table FW has more putrescible fraction and fewer impurities than kitchen FW.•Three anaerobic digestion scenarios are compared with incineration practice.•AD followed by composting digestate is best ...in most of the impact categories.•AD followed by gasifying digestate outputs the largest electricity.•Gas engine emission, and water consumption should be lowered.
A life cycle assessment (LCA) was conducted to determine the best solution for dealing with the food waste (FW) generated in Singapore eateries. Since the representativeness of the life cycle inventory (LCI) data determined the overall quality of the LCA, this study made a significant endeavor to capture the local specificities, such as waste composition, water supply and treatment plant operation. Characterization data showed that eatery FW from Singapore contained 16% non-biodegradable impurities (such as plastic and metal) and a higher methane generation potential was found in FW from the dining table than in FW from the kitchen. Based on the FW chemical element composition, mass balances were established for the four examined scenarios, including incineration (Inci), anaerobic digestion (AD) followed by composting (ADcom), AD followed by incineration (ADinci) and AD followed by gasification (ADgas). Because of the environmental benefits from compost production in addition to electricity generation, ADcom outperformed other scenarios in all impact categories except Eutro (eutrophication), GW (global warming) and POC (photochemical ozone creation). The best score of GW was observed in ADgas, mainly ascribed to the highest electricity output and the carbon sequestration of biochar. The disadvantages of the AD scenarios in Eutro and POC were associated with NOx and CO emissions from the biogas engine. Finally, the sensitivity analysis demonstrated that better environmental profiles could be achieved if improvements can be made by minimizing water usage, mitigating gas engine pollution, and diverting as much FW as possible from incineration plants to AD plants. However, based on the local context, source separation was not an urgent issue for improving the sustainability of eatery FW management.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
The electrochemical performance of MnO2 nanorods prepared by a precipitation reaction was investigated in 0.5 mol/L Li2SO4, Na2SO4, and K2SO4 aqueous electrolyte solutions. Results show that at the ...slow scan rates, the nanorods show the largest capacitance (201 F/g) in Li2SO4 electrolyte since the reversible intercalation/deintercalation of Li+ in the solid phase produces an additional capacitance besides the capacitance based on the absorption/desorption reaction. At fast scan rates they show the largest capacitance in the K2SO4 electrolyte due to the smallest hydration radius of K+, highest ionic conductivity, and lowest equivalent series resistance (ESR). An asymmetric activated carbon (AC)/K2SO4/MnO2 supercapacitor could be cycled reversibly between 0 and 1.8 V with an energy density of 17 Wh/kg at 2 kW/kg, much higher than those of the AC/K2SO4/AC supercapacitor and AC/Li2SO4/LiMn2O4 hybrid supercapacitor. Moreover, this supercapacitor exhibits excellent cycling behavior with no more than 6% capacitance loss after 23 000 cycles at 10C rate even when the dissolved oxygen is not removed.
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IJS, KILJ, NUK, PNG, UL, UM
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