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Due to the continuous worldwide threats from infectious diseases, exploring novel antibacterial materials based on renewable, biodegradable and biocompatible polymers, like poly(lactic acid) (PLA), is essential for the development of advanced personal protective equipment, but the incorporation of a large amount of inorganic piezoelectric nanoparticles to endow it with a piezoelectric antibacterial effect deteriorated the unique properties of PLA. In this work, a self-assembling hydrazide nucleator (HNA) was introduced into PLA through melt blending, while PLA–HNA fibers were prepared by melt spinning–hot drawing dual processes, and further knitted into a plain fabric. The incorporation of HNA improved the spinnability/uniformity of the fibers, and promoted the formation of a highly oriented crystalline structure of fibers under a high draw ratio (DR), exhibiting a higher degree of crystallinity/orientation in both crystalline and amorphous regions than neat PLA fiber. With increasing DR, the shish-kebab crystallinity of the fibers changed to fibrillar crystallinity, forming compact microfibrillar structures along the drawing direction, and the tensile strength and modulus increased remarkably, reaching as high as 645.27 MPa and 8.87 GPa at a DR of 6. Meanwhile the open-circuit voltage (Vpp), short-circuit current (Isc), and piezoelectric sensitivity increased with DR, and compared with PLA fiber, incorporating HNA improved the piezoelectricity of the fiber significantly with high cycling stability. The knitted fabric with twisted and tightly interweaved fibers exhibited a much enhanced piezoelectric response, generating Vpp and Isc signals of 9.17 V and 210 nA, respectively. Moreover, both the PLA–HNA fiber and fabric inhibited E. coli bacteria almost completely by ultrasonic coculture with Vpp signals of 89.3 and 95.8 mV, respectively, reaching an inhibition rate of more than 99%, exhibiting an excellent intrinsic piezoelectric and antibacterial effect, and showing promising potential as personal protective equipment. [ABSTRACT FROM AUTHOR]

The feasibility of using preheated kerosene and pre-evaporation to assist in liquid kerosene detonation ignition and self-sustaining combustion under near-ramjet limit conditions was investigated. Additionally, the detonation decoupling and self-sustaining mechanisms were analyzed in depth. Owing to the forced heat transfer effect of supersonic flow on kerosene droplets, self-sustaining detonation combustion could not be achieved using preheated kerosene alone. The detonation wave was still decoupled due to the forced heat exchange effect of the cold kerosene droplets on the detonation wave, even if the distribution of C12H23 reached the detonation conditions through the pre-evaporation of fuel. [ABSTRACT FROM AUTHOR]

During the COVID-19 pandemic, panic buying, price inflation, and the pollution of production processes led to economic and social unrest. In response to the current situation, the current research takes less account of the subjective perception of public panic buying and the lack of reference to the reality of effective governance. First, this paper uses prospect theory to portray the public's perceived value of goods in panic buying and non-panic buying situations. Then, drawing on the experience of effective governance in China, a tripartite evolutionary game model of local government, the public and green smart supply chain enterprises is constructed under the reward and punishment mechanism of the central government. Then, this paper analyzes the strategic choices of each game player and the stability of the system equilibrium. The structure of the study suggests the following. (1) Improving local government subsidies and penalties, the cost of positive response and the probability of response can lead to an evolutionary direction where the public chooses not to panic buy and green smart supply chain enterprises choose to ensure a balance between supply and demand and increase pollution control in the production process. (2) Our study yields three effective combinations of evolutionary strategies, of which an ideal combination of evolutionary strategies exists. Non-ideal evolutionary strategy combinations can occur due to improper incentives and penalties of local governments and misallocation of limited resources. However, we find four paths that can transform the non-ideal evolutionary strategy combination into an ideal evolutionary strategy combination. (3) The central government's reward and punishment mechanism is an important tool to stabilize the tripartite strategy, but the central government cannot achieve effective governance by replacing incentives with punishment. [ABSTRACT FROM AUTHOR]

Two-phase rotating detonation ramjets are considered to be suitable for aerospace applications due to their high thermodynamic cycle efficiency. These engines have an extremely complex internal flow field, in which the liquid fuel undergoes physical and chemical processes such as fragmentation, evaporation, mixing, and combustion; these processes also interact with detonation waves that have significant gradients. This makes it difficult to simulate a three-dimensional (3D) full-process rotating detonation combustion chamber. Here, based on the Euler–Lagrangian simulation method, a 3D numerical combustion chamber was simulated using kinetic theory and the constant thermal physical property parameter (TPPP) calculation method. The accuracy of these methods was then compared with the existing experimental results and theoretical values. Calculating the TPPPs using kinetic theory brought about a relatively high-pressure peak and detonation wave temperature; the detonation wave profile was also finer and more precise. The detonation wave propagation velocity of the two-phase detonation is estimated to be about 60% of the theoretical gas-phase CJ velocity. The calculation method of physical parameters has relatively little influence on the engine's operating frequency and the detonation wave's propagation velocity but has a more significant influence on the peak pressure. Constant TPPPs can be used when the Kelvin–Helmholtz–Rayleigh–Taylor model with insufficient precision is used to consider the breakup of droplets and leads to the acceleration of the propagation speed of two-phase detonation waves. [ABSTRACT FROM AUTHOR]

Two-phase rotating detonation ramjets are considered to be suitable for aerospace applications due to their high thermodynamic cycle efficiency. These engines have an extremely complex internal flow field, in which the liquid fuel undergoes physical and chemical processes such as fragmentation, evaporation, mixing, and combustion; these processes also interact with detonation waves that have significant gradients. This makes it difficult to simulate a three-dimensional (3D) full-process rotating detonation combustion chamber. Here, based on the Euler–Lagrangian simulation method, a 3D numerical combustion chamber was simulated using kinetic theory and the constant thermal physical property parameter (TPPP) calculation method. The accuracy of these methods was then compared with the existing experimental results and theoretical values. Calculating the TPPPs using kinetic theory brought about a relatively high-pressure peak and detonation wave temperature; the detonation wave profile was also finer and more precise. The detonation wave propagation velocity of the two-phase detonation is estimated to be about 60% of the theoretical gas-phase CJ velocity. The calculation method of physical parameters has relatively little influence on the engine's operating frequency and the detonation wave's propagation velocity but has a more significant influence on the peak pressure. Constant TPPPs can be used when the Kelvin–Helmholtz–Rayleigh–Taylor model with insufficient precision is used to consider the breakup of droplets and leads to the acceleration of the propagation speed of two-phase detonation waves. [ABSTRACT FROM AUTHOR]

Abstract: Introduction: Novel technetium-labeled ligands, 99mTc-NCAM and 99mTc-NHAM were developed from the N-methyl-d-aspartate (NMDA) receptor agonist memantine as a lead compound by coupling with N2S2. This study evaluated the binding affinity and specificity of the ligands for the NMDA receptor. Methods: Ligand biodistribution and uptake specificity in the brain were investigated in mice. Binding affinity and specificity were determined by radioligand receptor binding assay. Three antagonists were used for competitive binding analysis. In addition, uptake of the complexes into SH-SY5Y nerve cells was evaluated. Results: The radiochemical purity of 99mTc-labeled ligands was more than 95%. Analysis of brain regional uptake showed higher concentration in the frontal lobe and specific uptake in the hippocampus. 99mTc-NCAM reached a higher target to nontarget ratio than 99mTc-NHAM. The results indicated that 99mTc-NCAM bound to a single site on the NMDA receptor with a K d of 701.21 nmol/l and a B max of 62.47 nmol/mg. Specific inhibitors of the NMDA receptor, ketamine and dizocilpine, but not the dopamine D2 and 5HT1A receptor partial agonist aripiprazole, inhibited specific binding of 99mTc-NCAM to the NMDA receptor. Cell physiology experiments showed that NCAM can increase the viability of SH-SY5Y cells after glutamate-induced injury. Conclusions: The new radioligand 99mTc-NCAM has good affinity for and specific binding to the NMDA receptor, and easily crosses the blood–brain barrier; suggesting that it might be a potentially useful tracer for NMDA receptor expression. [Copyright &y& Elsevier]