The effect of hyperglycemia on blood brain barrier of rats with focal cerebral ischemia/reperfusion injury

Objective： To determine whether hyperglycemia could aggravate the microvascular damage in ischemic stroke. Methods： Hyperglycemia model was made by injection of streptozocin through subcutaneous injection in wistar rats. Using the suture model, the rats were subjected to 3h of focal ischemia and different times of reperfusion, including 6,12,24,48,96h and 7d. TIC dyeing was used to Show the infarction area of rats. The infarctive volume of rats were calculated by computer imaging analysis system;Matrix metalloproteinase （MMP-2） and （MMP-9）were detected by immunohistochemistly and in situ hybridization histochemistly in Wistar rats. Results： The infarctive volume was siginificantly larger in hyperglycemic rats than that of nonhyperglycemic rats. The level of MMP-2, MMP-9 expression in the group of hyperglycemic rats was higher than that of nonhyperglycemic rats. Conclusion： Hyperglycemia aggravated the injury of focal ischmia-repeffusion in wistar rats and the higher expression of MMP-2,MMP-9 might be one of the mechanism in aggravation of focal ischemia/repeffusion injury.

Comprehensive study on fail-safe topological design method for 3D structures

Fail-safe topology optimization is valuable for ensuring that optimized structures remain operable even under damaged conditions.By selectively removing material stiffness in patches with a fixed shape,the complex phenomenon of local failure is modeled in fail-safe topology optimization.In this work,we first conduct a comprehensive study to explore the impact of patch size,shape,and distribution on the robustness of fail-safe designs.The findings suggest that larger sizes and finer distribution of material patches can yield more robust fail-safe structures.However,a finer patch distribution can significantly increase computational costs,particularly for 3D structures.To keep computational efforts tractable,an efficient fail-safe topology optimization approach is established based on the framework of multi-resolution topology optimization(MTOP).Within the MTOP framework,the extended finite element method is introduced to establish a decoupling connection between the analysis mesh and the topology description model.Numerical examples demonstrate that the developed methodology is 2 times faster for 2D problems and over 25 times faster for 3D problems than traditional fail-safe topology optimization while maintaining similar levels of robustness.

Whether and When Superhydrophobic/Superoleophobic Surfaces Are Fingerprint Repellent

Driven by the ever-increasing demand for fingerprint-resistant techniques in modern society,numerous researches have proposed to develop innovative antifingerprint coatings based on superhydrophobic/superoleophobic surface design.However,whether superhydrophobic/superoleophobic surfaces have favorable repellency to the microscopic fingerprint is in fact an open question.Here,we establish a reliable method that enables evaluating the antifingerprint capability of various surfaces in a quantitative way.We show that superhydrophobicity is irrelevant with fingerprint repellency.Regarding superoleophobic surfaces,two distinct wetting states of microscopic fingerprint residues,i.e.,the"repellent"and the“collapsed”states,are revealed.Only in the"repellent"state,in which the fingerprint residues remain atop surface textures upon being pressed,superoleophobic surfaces can bring about favorable antifingerprint repellency,which correlates positively with their receding contact angles.A finger-deformation-dependent intrusion mechanism is proposed to account for the formation of diferent fingerprint wetting states.Our findings offer important insights into the mechanism of fingerprint repellency and will help the design of high-performance antifingerprint surfaces for diverse applications.

Efficient,high-resolution topology optimization method based on convolutional neural networks

Topology optimization is a pioneer design method that can provide various candidates with high mechanical properties.However,high resolution is desired for optimum structures,but it normally leads to a computationally intractable puzzle,especially for the solid isotropic material with penalization(SIMP)method.In this study,an efficient,high-resolution topology optimization method is developed based on the super-resolution convolutional neural network(SRCNN)technique in the framework of SIMP.SRCNN involves four processes,namely,refinement,path extraction and representation,nonlinear mapping,and image reconstruction.High computational efficiency is achieved with a pooling strategy that can balance the number of finite element analyses and the output mesh in the optimization process.A combined treatment method that uses 2D SRCNN is built as another speed-up strategy to reduce the high computational cost and memory requirements for 3D topology optimization problems.Typical examples show that the high-resolution topology optimization method using SRCNN demonstrates excellent applicability and high efficiency when used for 2D and 3D problems with arbitrary boundary conditions,any design domain shape,and varied load.

Multi-resolution nonlinear topology optimization with enhanced computational efficiency and convergence

Huge calculation burden and difficulty in convergence are the two central conundrums of nonlinear topology optimization(NTO).To this end,a multi-resolution nonlinear topology optimization(MR-NTO)method is proposed based on the multiresolution design strategy(MRDS)and the additive hyperelasticity technique(AHT),taking into account the geometric nonlinearity and material nonlinearity.The MR-NTO strategy is established in the framework of the solid isotropic material with penalization(SIMP)method,while the Neo-Hookean hyperelastic material model characterizes the material nonlinearity.The coarse analysis grid is employed for finite element(FE)calculation,and the fine material grid is applied to describe the material configuration.To alleviate the convergence problem and reduce sensitivity calculation complexity,the software ANSYS coupled with AHT is utilized to perform the nonlinear FE calculation.A strategy for redistributing strain energy is proposed during the sensitivity analysis,i.e.,transforming the strain energy of the analysis element into that of the material element,including Neo-Hooken and second-order Yeoh material.Numerical examples highlight three distinct advantages of the proposed method,i.e.,it can(1)significantly improve the computational efficiency,(2)make up for the shortcoming that NTO based on AHT may have difficulty in convergence when solving the NTO problem,especially for 3D problems,(3)successfully cope with high-resolution 3D complex NTO problems on a personal computer.

BIM-based automated design for HVAC system of office buildings-An experimental study

Although computer technologies have greatly advanced in recent years and help engineers improve work efficiency,the heating,ventilation,and air conditioning(HVAC)design process is still very time-consuming.In this paper,we propose a conceptual framework for automating the entire design process to replace current human-based HVAC design procedures.This framework includes the following automated processes:building information modeling(BIM)simplification,building energy modeling(BEM)generation&load calculation,HVAC system topology generation&equipment sizing,and system diagram generation.In this study,we analyze the importance of each process and possible ways to implement them using software.Then,we use a case study to test the automated design procedure and illustrate the feasibility of the new automated design approach.The purpose of this study is to simplify the steps in the traditional rule-based HVAC system design process by introducing artificial intelligence(Al)technology based on the traditional computer-aided design(CAD)process.Experimental results show that the automatic processes are feasible,compared with the traditional design process can effectively shorten the design time from 23.37 working hours to nearly 1 hour,and improve the efficiency.