Background: Oxidative stress and neuroinflammation play crucial roles in the progression of neonatal hypoxic-ischemic brain damage (HIBD). Genistein, a natural phytoestrogen, has been found to protect against ischemic brain injury. However, its effects and potential mechanisms in HIBD have not yet been explored.Methods: A neonatal mouse model of hypoxia-ischemia (HI) and a cell model of oxygen-glucose deprivation/reperfusion (OGD/R) were employed. In the in vivo study, genistein (10 mg/kg; ip) was administered in mice once daily for 3 consecutive days before the operation and once immediately after HI.The effects of genistein treatment on acute brain damage and long-term responses were evaluated. Neuronal injury and apoptosis were estimated using hematoxylin and eosin (H&E) and terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) staining, respectively. The expression of apoptosis-related proteins were also measured by Western blot analysis. Dihydroethidium (DHE) staining and glutathione (GSH) and malondialdehyde (MDA) production were determined to assess the extent of oxidative stress. The messenger RNA (mRNA) levels of proinflammatory cytokines were detected using real-time quantitative polymerase chain reaction (RT-qPCR) to evaluate the extent of neuroinflammation. In the in vitro study, cell counting kit-8 (CCK-8) and lactate dehydrogenase (LDH) assays, as well as propidium iodide (PI) staining, were performed to analyse the neuroprotective effects of genistein on primary cortical neurons. Western blot assays were used to detect the levels of nuclear factor erythroid 2-related factor 2 (Nrf2), heme oxygenase-1 (HO-1), phosphorylated inhibitor kappa B-α (p-IκB-α) and phosphorylated nuclear factor-kappa B (p-NF-κB) both in vivo and in vitro.Results: Our results showed that genistein treatment effectively reduced cerebral infarction, attenuated neuronal injury and apoptosis, and contributed to the long-term recovery of neurological outcomes and brain atrophy in neonatal HIBD mice. Moreover, genistein ameliorated HIBD-induced oxidative stress and neuroinflammation. Meanwhile, genistein significantly increased cell viability, reversed neuronal injury and decreased cell apoptosis after OGD/R injury. Finally, the activation of the Nrf2/HO-1 pathway and inhibition of the NF-κB pathway by genistein were verified in the brain tissues of neonatal mice subjected to HIBD and in primary cortical neurons exposed to OGD/R. Conclusions: Genistein exerted neuroprotective effects on HIBD by attenuating oxidative stress and neuroinflammation through the Nrf2/HO-1 and NF-κB signalling pathways.
The work herein employed COMSOL Multiphysics simulation and experiment to study the temperature distribution of water in a specially designed cylindrical microwave (MW) reactor with two magnetrons. A numerical model was developed by combining three modules including radio frequency (RF), fluid heat transfer, and nonisothermal fluid flow. The experimental results of the temperature distribution corresponded with simulative values. Additional experiments and simulations of a single microwave port as well as two different combinations of ports were carried out to confirm the uniformity of the results. Results show that two parallel waveguides are better than both a single waveguide and two perpendicular waveguides in terms of uniformity and efficiency at the same incident power.
This work presents the study on solid−liquid mass-transfer performance of suspension in a rotating packed bed (RPB). The calculation model of solid−liquid mass-transfer coefficient (k S ) is deduced on the basis of the mass conversation law. The k S in RPB is measured using the suspension of cationexchange resin particle reaction with NaOH solution. The effects of different operating conditions such as the dispersion time (t) in a stirred tank reactor (STR), the rotating speed (N), the mesh packing thickness (w), the liquid volume flow rate (L T ), and the solid loading (e) on the RPB are investigated. The results show that k S increases with the increase of N and w; it increases first and then tends to remain constant with the increase of t and L T . However, e has little influence on k S . A nondimensional equation for Sh is established, and the predicted and experimental values of Sh are in good agreement with a deviation within ±15%. Furthermore, the maximum value of Sh of 124 is obtained under the conditions, t = 0.5 h in STR, N = 2200 rpm, L T = 56 L/h, e = 15 g/L, and w = 24 mm, which is higher than those in the microreactor (MR) and STR. Here, RPB exhibits great application potential in the solid− liquid mass-transfer or reaction process.
This work presents the study on solid-liquid mass transfer performance of suspension in a rotating packed bed (RPB). The calculation model of solid-liquid mass transfer coefficient (ks) is deduced on the basis of the mass conversation law. The ks in RPB is measured using the suspension of cation exchange resin particle reaction with NaOH. The effects of different operating parameters such as pre-dispersion time (t), rotating speed (N), mesh packing thickness (w), liquid volume flow rate (LT), and solid loading (e) are investigated. The results show that the ks increases with the increase of N and w, and increases first and then tends to remain constant with the increase of t and LT. However, the e has no influence on ks. The obtained ks ranges from 1.00×10-5 m/s to 2.60×10-4 m/s which is higher than that in microreactor (MR) under the similar experimental conditions.
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