Puerarin protects against sepsis-associated encephalopathy by inhibiting NLRP3/Caspase-1/GSDMD pyroptosis pathway and reducing blood-brain barrier damage.

Puerarin (Pue), an isoflavone compound extracted from Pueraria, has been shown to inhibit inflammation and reduce cerebral edema. The neuroprotective effect of puerarin has attracted much attention in recent years. Sepsis-associated encephalopathy (SAE) is a serious complication of sepsis that causes damage to the nervous system. This study aimed to investigate the effect of puerarin on SAE and elucidate the potential underlying mechanisms. A rat model of SAE was established by cecal ligation and puncture, and puerarin was injected intraperitoneally immediately after the operation. Puerarin was found to improve the survival rate and neurobehavioral score of SAE rats, alleviate symptoms, inhibit the level of brain injury markers NSE and S100ß, and improve the pathological changes in rat brain tissue. Puerarin was also found to inhibit the level of factors related to the classical pathway of pyroptosis, such as NLRP3, Caspase-1, GSDMD, ASC, IL-1ß, and IL-18. Puerarin also reduced the brain water content and penetration of Evan's Blue dye in SAE rats, and reduced the expression of MMP-9. In the in vitro experiments, we further confirmed the inhibitory effect of puerarin on neuronal pyroptosis by establishing a pyroptosis model in HT22 cells. Our findings suggest that puerarin may improve SAE by inhibiting the classical pathway of NLRP3/Caspase-1/GSDMD-mediated pyroptosis and reducing blood-brain barrier damage, thus playing a role in brain protection. Our study may provide a novel therapeutic strategy for SAE.

Experimental Study on Mechanical Properties of Root-Soil Composite Reinforced by MICP.

Mechanical properties of undisturbed root-soil composites were investigated through direct shear tests under different cementation concentrations by microbially induced carbonate precipitation (MICP). The results show that MICP has a significant strengthening effect on the undisturbed root-soil composite, and the maximum shear strength increases by about 160% after grouting. The shear strength of root-soil composites increases with the increase in calcium chloride concentration, and the shear strength increases the most when the concentration is 0.75M. Calcium carbonate formed by MICP treatment has cementitious properties, which increases the cohesion and internal friction angle of the root-soil composite by about 400% and 120%, respectively. The results show that it is feasible to solidify slope and control soil erosion together with microbial and vegetation roots. The research results can serve as a scientific basis and reference for the application of MICP technology in vegetation slope protection engineering.

An agent-based study on the airborne transmission risk of infectious disease in a fever clinic during COVID-19 pandemic.

Prevention of nosocomial infections is particularly important for the control of COVID-19 pandemic. We conducted a field study and performed extensive numerical simulations of infection transmission in a fever clinic during pandemic through an agent-based model with pedestrian dynamic and an infection transmission model. Furthermore, we evaluated the cross-infection risk of the patients influenced by the patient inject flow, medical service capability and plane layout. The service capability of fever clinic is determined by the least efficient medical session. When patient inject flow exceeded the service capability, the average dwell time, contact time, exposure dose, and risk of infection of patients all increased dramatically. With the patient inject flow exceeding the service capability, the growth rate of the contact time between patients and the cross-infection risk increased by 11.5-fold and 29.5-fold, respectively. The plane layout of the fever clinic affected the exposure dose and risk of infection. The waiting areas in the fever clinic had the highest risk, where the cumulative exposure dose of virus occupied up to 66.5% of the total. Our research will help to evaluate the biosafety of hospital buildings used for the diagnosis and treatment of infectious diseases.

Lipoxin A4 protects against paraquat­induced acute lung injury by inhibiting the TLR4/MyD88­mediated activation of the NF­κB and PI3K/AKT pathways.

Paraquat (PQ) causes serious oxidative stress and inflammatory responses, particularly to the lungs. Since lipoxin A4 (LXA4) functions as an anti­inflammatory mediator, the present study aimed to explore its effects on PQ­induced acute lung injury (ALI) and to elucidate the possible underlying mechanisms. PQ was administered to male SD rats and RAW264.7 cells to establish a model of poisoning, and LXA4 was used as an intervention drug. LXA4 treatment attenuated PQ­induced lung injury, and this was accompanied by decreased tumor necrosis factor (TNF)­α and interleukin (IL)­1ß secretion levels, and reduced oxidative stress damage. Additionally, LXA4 treatment inhibited the activation of the inflammation­related signaling molecules, Toll­like receptor 4 (TLR4), myeloid differentiation primary response 88 (MyD88), nuclear factor (NF)­κB p65, p­phosphoinositide 3­kinase (PI3K) and p­AKT. Furthermore, the in vitro experiments further confirmed that the beneficial effects of LXA4 on PQ­induced damage were TLR4­dependent. Hence, the present study demonstrated that LXA4 attenuated PQ­induced toxicity in lung tissue and RAW264.7 macrophages, and that this protective effect may be closely related to the mitigation of inflammatory responses, oxidative stress damage and the TLR4/MyD88­mediated activation of the PI3K/AKT/NF­κB pathway.

Field study to characterize customer flow and ventilation rates in retail buildings in Shenzhen, China.

Reduction of the customers' exposure risk of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in the retail buildings, i.e., supermarkets and small shops where residents purchase daily necessities is of prime importance during pandemic. In this study, the main influencing factors of the exposure risk of SARS-CoV-2, namely the occupant density, dwell time, and fresh air volume per person, were on-sited measured in 5 supermarkets and 21 small shops in Shenzhen, China. The small shops with an occupant area per person of 4.7 m2/per presented a more crowded environment than the supermarkets with an occupant area per person of 18.8 m2/per. The average dwell time of customers in the supermarkets linearly increased with the floor area and its probability distribution was fitted well by the Gamma distribution with a shape parameter of 3.0. The average dwell time of customers in the supermarkets was relatively longer than the combination of five types of small shops. In addition, the measured average outdoor air change rate of the small shops by natural ventilation was 10.7 h-1, while that of the supermarkets by mechanical ventilation was only 0.7 h-1. Correspondingly, the CO2 concentration in the small shops was 100-150 ppm lower than the supermarkets. The small shops provided an average fresh air volume per person of 216 m3/(h·per), far exceeding the supermarkets with a value of 95 m3/(h·per).