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BACKGROUND: As an essential trace element for mammalian species, selenium (Se) possesses powerful antioxidant properties and is a potential regulator of intestinal microbiota. However, effects of Cardamine hupingshanensis aqueous extract (CE), rich in Se, on balancing the intestinal redox status and regulating gut microbiota have been neglected. RESULTS: An Se‐deficient rat model was established by feeding a low‐Se diet (LD) for 5 weeks and CE was then supplemented to LD or normal‐Se‐diet (ND) rats. Antioxidant enzyme activities and short‐chain fatty acids (SCFA) concentration were increased by CE in both LD and ND rats. CE improved the intestinal morphology of LD rats impaired by deficient Se. Intestinal microbiota demonstrated various changes; for example, Butyrivibrio was increased in LD rats, while Bacteroides, Christensenellaceae, Clostridiaceae and Blautia were enhanced in ND rats. CONCLUSION: Our findings provide evidence that CE shows potential in improving intestinal redox status and regulating gut microbiota. © 2020 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

Combustion optimization is an effective technique for energy conservation in power plants. An accurate NO X emission estimation model is crucial for combustion optimization. A novel NO X emission estimation model is proposed that integrates an improved random forest (RF) and a wrapper feature selection based on an improved binary flower pollination algorithm (FPA). Three improvements to the basic FPA are proposed, an elite-selection strategy, a mutation operator, and a dynamic switch probability. Moreover, the optimization precision of the proposed FPA is compared to those of five other optimization algorithms. A feature selection method based on the proposed FPA is employed to identify the optimal inputs for the NO X emission model. In addition, a fine-tuning mechanism to update the population (based on mutual information) is designed and embedded in the feature selection process to speed up convergence. To improve the basic RF, an ensemble pruning algorithm based on a back propagation neural network that can evaluate the importance of each tree and prune “detrimental” trees is developed. With the optimal inputs, the NO X emission model is constructed using the improved RF. The prediction results demonstrate that it is of higher accuracy and better robustness compared to the basic RF and the three other models. The designed feature selection could also decrease the computational complexity and improve the prediction accuracy. [ABSTRACT FROM AUTHOR]

Iron based nanomedicine (IBNM) has been one powerful diagnostic tool as a magnetic resonance imaging (MRI) contrast agent (CA) in the clinic for years. Conventional IBNMs are generally employed as T 2 -MRI CAs, but most of them are constrained in clinical indication expansion by magnetic susceptibility artifacts. In comparison, extremely small iron oxide (ESIO) with a core size less than 5 nm has demonstrated the T 1 -MRI effect, which provides prospects for a Gd-based agent alternative. Nevertheless, currently developed ESIOs for T 1 -MRI CAs always require harsh conditions such as a high temperature and high boiling point reagent. Moreover, very few of the currently developed ESIOs meet the stringent pharmaceutical standard. Herein, on the basis of a crystal nuclear precipitation-dissolution equilibrium mechanism and outer/inner sphere T 1 -MRI theory, monodisperse ESIOs with an average size of 3.43 nm (polydispersity index of 0.104) are fabricated using a moderate cooling procedure with mild coprecipitation reaction conditions. The as-synthesized ESIOs display around 3-fold higher T 1 MRI signal intensity than that of commercial Ferumoxytol (FMT), comparable to that of Gd-based CAs in vitro. Additionally, the T 1 -MRI performance of the ESIOs is pH dependent and delivers bright signal augmentation. Eventually, the internalization into mesenchymal stem cells of the ESIO is realized in the absence of a transferring agent. Considering the identical structure and composition of the ESIOs as compared to that of FMT, they could meet the pharmaceutical criteria, thus providing great potential as T 1 -MRI Cas, for instance as stem cell tracers.