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The effect of 135Xe and 149Sm on the reactivity of a typical megawatt heat pipe reactor had been studied by MCNP and SuperMC-CAS. The results showed that the reactivity introduced by 135Xe was only 8 pcm. The concentration of 149Sm increased with the core running time, highlighting its significant poisoning effect. A simplified calculation method for determining the equilibrium xenon poisoning value of a fast neutron reactor was proposed in this study. These results provided valuable insights for assessing xenon and samarium poisoning in low-power, fast neutron reactors. [ABSTRACT FROM AUTHOR]

BACKGROUND: Histopathological evaluation is currently the gold standard for grading gliomas; however, this technique is invasive. OBJECTIVE: This study aimed to develop and validate a diagnostic prediction model for glioma by employing multiple machine learning algorithms to identify risk factors associated with high-grade glioma, facilitating the prediction of glioma grading. METHODS: Data from 1114 eligible glioma patients were obtained from The Cancer Genome Atlas (TCGA) database, which was divided into a training set (n = 781) and a test set (n = 333). Fifty machine learning algorithms were employed, and the optimal algorithm was selected to construct a prediction model. The performance of the machine learning prediction model was compared to the clinical prediction model in terms of discrimination, calibration, and clinical validity to assess the performance of the prediction model. RESULTS: The area under the curve (AUC) values of the machine learning prediction models (training set: 0.870 vs. 0.740, test set: 0.863 vs. 0.718) were significantly improved from the clinical prediction models. Furthermore, significant improvement in discrimination was observed for the Integrated Discrimination Improvement (IDI) (training set: 0.230, test set: 0.270) and Net Reclassification Index (NRI) (training set: 0.170, test set: 0.170) from the clinical prognostic model. Both models showed a high goodness of fit and an increased net benefit. CONCLUSION: A strong prediction accuracy model can be developed using machine learning algorithms to screen for high-grade glioma risk predictors, which can serve as a non-invasive prediction tool for preoperative diagnostic grading of glioma. [ABSTRACT FROM AUTHOR]

Fine tailoring of the subtle movements of a hydrogel actuator through simple methods has widespread application prospects in wearable electronics, bionic robots and biomedical engineering. However, to the best of our knowledge, this challenge is not yet completed. Inspired by the diffusion-reaction process in nature, a hydrogel gripper with the capability of fine movement was successfully prepared based on the spatiotemporal fabrication of the polypyrrole (PPY) pattern in a poly (N-isopropylacrylamide) (PNIPAM) hydrogel. The hydrogel was given gradient porous structures using a one-step UV irradiation method. Moreover, photothermal PPY patterns on the hydrogel were obtained through spatiotemporal mineralization of ferric hydroxide followed by the polymerization of pyrrole in a controllable manner. Taking advantage of the unique structures, the hydrogel gripper can not only achieve reversible grasping–releasing of substrates with the tuning of temperature (similar to that of hands), but also generate delicate movement under the irradiation of light (resembling that of finger joints). The strategy reported here is easily accessible and there is no need for sophisticated templates, therefore making it superior to other existing methods. We believe this work will provide references for the design and application of more advanced soft actuators. [ABSTRACT FROM AUTHOR]

Currently, researchers are looking for efficient and sustainable methods to synthesize biochar for the adsorption of pollutants. In this study, biochar with high specific surface area, tunable pore structure, and abundant functional groups were prepared from waste cotton woven (WCW) using low-dosage Fe(NO3)3 activation at 400–900 °C. The biochar obtained at 800 °C possessed the excellent specific surface area of 1167.37 m2/g with a unique micro-mesoporous structure. XRD analysis showed that the Fe species changed from Fe2O3 to Fe3O4 and then Fe0 with the increase of pyrolysis temperature. TEM images further confirmed the template effect of iron oxides for mesoporous formation. The effect of Fe(NO3)3 on the pyrolysis pathway of waste cotton woven was systematically investigated by TG and XPS analyses to explore the pore development of biochar. The results indicated that Fe(NO3)3 could enhance the dehydration, decarbonylation and dehydroxylation of WCW components, thereby reducing the temperature required for WCW pyrolysis. Moreover, the synergistic effect of Fe and N species improved the development of microporous and mesoporous structure through carbon structure corrosion and reorganization, and volatile release. Additionally, satisfactory adsorption capacity for Eriochrome Black T (456.01 mg/g) of the prepared biochar was obtained at 25 °C. This study demonstrated that low-dosage Fe(NO3)3 activation of waste cotton woven could be used as a facile method to prepare promising inexpensive biochar for contaminants removal. [ABSTRACT FROM AUTHOR]

The practical application of Li−S batteries is still limited by the fundamental problems of the insulation properties of sublimed S and the "shuttle effect" of polysulfides. S‐doped porous carbon cage (SPCC) obtained by the catalytic guidance methodology is employed as a highly efficient S host material for Li−S batteries, which presents the cage‐like morphology coupled with abundant pore channels. Compared to the undoped PCC, SPCC exhibits higher electrical conductivity. The composite of sublimed S and SPCC (S@SPCC) employed as cathode for Li−S batteries possesses a higher reversible capacity, superior rate capability and better durability in comparison with that of S@PCC cathode. The synergistic effect of robust matrix associated with good electrical conductivity and abundant pore channels of SPCC is beneficial for the fast electron transport and shorten the Li‐ion diffusion distance. Besides, S doping possesses the positive function to attract Li‐polysulfides, inhibiting the shuttle of Li‐polysulfides and contributing to the superior electrode behavior of the S@SPCC cathode. [ABSTRACT FROM AUTHOR]