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Physical calculations of reactor cores are fundamental for reactor core design and nuclear safety analysis. The second generation of core calculation theory and methods based on advanced component homogenization theory and modern coarse grid block methods are commonly used in reactor core physics calculations. However, due to the fact that the two-step method of component homogenization does not accurately provide the grid rod power, the modified two-step method of cell homogenization based on the pin-by-pin homogenization theory of core calculations has gradually become a research hot spot in core calculations. Compared with the two-step method of component homogenization, the pin-by-pin calculation scheme only carries out the homogenization calculation for each cell in the component, which preserves the non-uniformity of different cells in the component, reduces the approximation and assumption in the core calculation, and can calculate the core number more accurately, which is conducive to the safety analysis of the core. However, the SP3/GSP3 methods currently in common use for pin-by-pin calculations still suffer from limitations in balancing computational accuracy and efficiency. In this regard, this paper aims to establish a core calculation method named quasi-diffusion theory which considers both computational efficiency and computational accuracy. First, the 3D quasi-diffusion equation was derived and established from neutron transport theory. Unlike the traditional diffusion equation, the formulation of the quasi-diffusion equation did not introduce a first-order approximation for the neutron angular flux, and the concept of the Eddington factor was introduced to deal with the leakage term of the neutron transport equation. The 3D quasi-diffusion equation was then formulated. In addition, a numerical solution model for the quasi-diffusion equation was developed by referring to traditional numerical solutions of the diffusion equation such as the transverse integral equation and using the nonlinear iterative cross section method. Second, since the Eddington factor was the key parameter in solving the quasi-diffusion equation, the solution of the quasi-diffusion equation depends on whether the Eddington factor was exact or not. In this paper, the Eddington factor was regarded as the homogenization parameter similar to other small group sections. The solution was obtained using Serpent, a modified version of the Monte Carlo program. Finally, several cases including the whole core model and the color-set assembly model were employed to validate the method, and the results were compared with the traditional diffusion and Monte Carlo reference solutions. By comparing the numerical output results under each model, the results show that for reactor cores with complex structures and strong heterogeneity, the accuracy of quasi-diffusion calculations is significantly better than that of traditional diffusion calculations, and the computationally efficient of the two methods is similar. In summary, the quasi-diffusion equation approximation, as a nonlinear method to approximate the neutron transport equation, is a computationally efficient and accurate method. It has great promise for new core calculations with strong neutron anisotropy and complex neutron energy spectrum.

Irreversible fibrosis following myocardial infarction (MI) stiffens the infarcted myocardium, which remains challenging to restore. This study aimed to investigate whether the injectable RLP12 hydrogel, derived from recombinant resilin protein, could serve as a vehicle for stem cells to enhance the function of the infarcted myocardium. The RLP12 hydrogel was prepared and injected into the myocardium of rats with MI, and brown adipose-derived mesenchymal stem cells (BADSCs) were loaded. The survival and differentiation of BADSCs in vivo were investigated using immunofluorescence one week and four weeks after treatment, respectively. The heart function, MI area, collagen deposition, and microvessel density were further assessed four weeks after treatment through echocardiography, histology, immunohistochemistry, and immunofluorescence. The RLP12 hydrogel was prepared with a shear modulus of 10–15 kPa. Four weeks after transplantation, the RLP12 hydrogel significantly improved cardiac function by increasing microvessel density and reducing infarct area size and collagen deposition in MI rats. Furthermore, the distribution ratio of collagen III to I increased in both the centre and edge areas of the MI, indicating the improved compliance of the infarct heart. Moreover, the RLP12 hydrogel also promoted the survival and differentiation of BADSCs into cardiac troponin T- and α-smooth muscle-positive cells. The RLP12 hydrogel can be utilised as an injectable vehicle of BADSCs for treating MI and regulating collagen I and III expression profiles to improve the mechanical microenvironment of the infarct site, thereby restoring heart function. The study provides novel insights into the mechanical interactions between the hydrogel and the infarct microenvironment. [ABSTRACT FROM AUTHOR]

In view of the characteristics of scattered distribution and various operation modes of various electrical equipment in coal mining face at present, a combined switch is used for control. The power supply mode, structure composition, protection system design, control mode design and operation mode design are described and analyzed. Two mobile transformers are used to supply power for one combined switch. CANBUS communication mode is used for the switch, and the switch circuit is simplified. Leakage protection, current protection and voltage protection have high sensitivity and reliability, and they ensure the safety of electrical equipment and operators. According to different electrical equipment and operation requirements, the corresponding start-up mode and control mode can be adopted, and it has good adaptability.

Background: Secukinumab, a fully humanized monoclonal antibody against IL-17A, was approved for the treatment of moderate-to-severe plaque psoriasis in the USA and European Union in 2015. Objectives: Secukinumab, a fully humanized monoclonal antibody against IL-17A, was approved for the treatment of moderate-to-severe plaque psoriasis in the USA and European Union in 2015. The aim of this study was to systematically evaluate the efficacy and safety of secukinumab for the treatment of moderate and severe plaque psoriasis and provide an evidence-based reference for clinical practice. Methods: PubMed, Google Scholar, Cochrane Library, and Clinical Trials databases were searched. Pivotal phase III clinical trials were analysed. RevMan was used for the statistical analysis of the data. Results: Seven pivotal phase III clinical trials were analysed. All trials evaluated secukinumab in moderate-to-severe plaque psoriasis and had two common primary end points: the proportion of respondents to the Psoriasis Area and Severity Index (PASI) and the proportion of respondents to the Investigator's Global Assessment (IGA). The total response ratios of PASI and IGA respondents in the secukinumab group were 82.8 and 71.3%, respectively, compared to placebo. Secukinumab was superior to etanercept, with risk ratios of 1.7 and 2.1, respectively. Secukinumab was generally well tolerated during the 1-year trial period. However, adverse events also occurred. Conclusion: Secukinumab was found to be more effective than etanercept and had an acceptable safety profile. Since psoriasis is an autoimmune disease that requires lifelong treatment, attention should be paid to its adverse effects. [ABSTRACT FROM AUTHOR]