Topology optimization of irregular flow domain by parametric level set method in unstructured mesh

Li Jiajing,Gao Liang,Ye Mengli,Li Hao,Li Lizhou 한국CDE학회 2022 Journal of computational design and engineering Vol.9 No.1

In this study, we present a novel method for the topology optimization of the irregular flow domain using a parametric level set method (PLSM). Some improvement was applied on the CS-RBFs (radial basis functions with compact support)-based PLSM to make it suitable for nonuniform mesh, expanding the range field of engineering application of the PLSM. The optimization problem is solved by a gradient-based algorithm with Stokes equations as state constraints, and the objective is set to minimize the power dissipation subject to the volume constraint of flow channels. A PLSM is introduced to avoid the direct solving of the Hamilton–Jacobi partial differential equation, which can have the potential to break through the restriction of relying on structured meshes because no finite difference scheme is required. Then, a self-adaption support radius approach is presented to allow the parametric level set to be evolved on the nonuniformed mesh, which can expand the application of the PLSM to more complicated engineering problems with irregular geometric shapes. A volume integration scheme is applied during the design sensitivity analysis to calculate the shape derivatives, allowing the nucleation of new holes. Numerical examples in two and three dimensions are provided to demonstrate the effectiveness of the proposed method.

Effects of Subdiaphragmatic Vagotomy in the MPTP-induced Neurotoxicity in the Striatum and Colon of Mice

Jiajing Shan,Youge Qu,Jiancheng Zhang,Li Ma,Kenji Hashimoto 대한정신약물학회 2022 CLINICAL PSYCHOPHARMACOLOGY AND NEUROSCIENCE Vol.20 No.2

Objective: Gut—microbiota—brain axis plays a role in the pathogenesis of Parkinson’s disease (PD). The subdiaphragmatic vagus nerve serves as a major modulatory pathway between the gut microbiota and the brain. However, the role of subdiaphragmatic vagus nerve in PD pathogenesis are unknown. Here, we investigated the effects of subdiaphragmatic vagotomy (SDV) on the neurotoxicity in the mouse striatum and colon after administration of 1-methyl-4-phenyl-1,2,3,6- tetrahydropyridine (MPTP). Methods: Sham or SVD was performed. Subsequently, saline or MPTP (10 mg/kg × 3, 2-hour interval) was administered to mice. Western blot analysis of tyrosine hydroxylase (TH) and dopamine transporter (DAT) in the striatum and phosphorylated α-synuclein (p-α-Syn) in the colon was performed. Results: Repeated administration of MPTP significantly caused reduction of TH and DAT in the striatum and increase of p-α-Syn in the colon of mice. However, SDV did not affect the reduction of TH and DAT in the striatum and increases in p-α-Syn in the colon after repeated MPTP administration. Conclusion: These data suggest that subdiaphragmatic vagus nerve doses not play a role in the MPTP-induced neurotoxicity in the brain and colon.

Millimeter-Wave Channel Modeling Based on A Unified Propagation Graph Theory

Chen, Jiajing,Yin, Xuefeng,Tian, Li,Kim, Myung-Don IEEE 2017 IEEE communications letters Vol.21 No.2

<P>In this letter, a unified propagation graph modeling approach is proposed, which is applicable to predicting multipath radio propagation by considering both specular components (SCs) and diffuse components (DCs). In this approach, the semi-deterministic graph modeling is used to generate multi-bounce DCs, and a single-lobe directive model is applied to reproducing individual single-bounce SCs together with DCs associated. The performance of the proposed approach is assessed by comparing measured channel characteristics with simulation results for 60 GHz millimeter-wave propagation in an office environment.</P>

Autism-like Behaviors in Male Juvenile Offspring after Maternal Glyphosate Exposure

Yaoyu Pu,Li Ma,Jiajing Shan,Xiayun Wan,BruceD.Hammock,Kenji Hashimoto 대한정신약물학회 2021 CLINICAL PSYCHOPHARMACOLOGY AND NEUROSCIENCE Vol.19 No.3

Objective: Exposure to the herbicide glyphosate during pregnancy and lactation may increase the risk for autism spectrum disorder (ASD) in offspring. Recently, we reported that maternal exposure of formulated glyphosate caused ASD-like behaviors in juvenile offspring. Here, we investigated whether maternal exposure of pure glyphosate could cause ASD-like behaviors in juvenile offspring. Methods: Water or 0.098% glyphosate was administered as drinking water from E5 to P21 (weaning). Behavioral tests such as grooming test and three-chamber social interaction test in male offspring were performed from P28 to P35. Results: Male offspring showed ASD-like behavioral abnormalities (i.e., increasing grooming behavior and social interaction deficit) after maternal exposure of glyphosate. Conclusion: The findings suggest that the exposure of glyphosate during pregnancy and lactation may cause ASD-like behavioral abnormalities in male juvenile offspring. It is likely that glyphosate itself, but not the other ingredients, may contribute to ASD-like behavioral abnormalities in juvenile offspring.

Sodium aescinate alleviates bone cancer pain in rats by suppressing microglial activation via p38 MAPK/c-Fos signaling

Yang Guang,Li Jiajing,Xu Qian,Xie Huilan,Wang Lijun,Zhang Minhao 대한독성 유전단백체 학회 2022 Molecular & cellular toxicology Vol.18 No.4

Background Bone cancer pain (BCP) severely compromises the life quality of patients with advanced cancer or bone metastases . Objective This study investigates the analgesic effect of sodium aescinate (SA) on BCP, and the underlying mechanisms within the spinal cord (SC) and dorsal root ganglion (DRG). Walker 256 cells were intratibially inoculated into rats to establish a BCP model. 10, 20, and 40 g/L of SA was intrathecally injected, respectively, and then, hyperalgesia and allodynia were evaluated by measuring the paw withdrawal threshold (PWT) and paw withdrawal latency (PWL). The effect of SA on neuroinflammation was observed by detecting the production of the pro-inflammatory cytokines based on RT-qPCR and ELISA. The NF-κB and p38 MAPK/c-Fos signaling was detected by WB analysis. Furthermore, RT-qPCR and WB analyses of Iba-1and CD206 were performed to assess microglial activation. Result The development of hyperalgesia and allodynia, and an increase of pro-inflammatory cytokines production, as well as microglial activation, were observed in the BCP rats. SA (40 g/L) not only relieved the pain-related behaviors induced by BCP but also suppressed the release of pro-inflammatory cytokines and the activation of microglia in the SC and DRG. SA could also inhibit p38 MAPK/c-Fos signaling in both the SC and DRG, which might contribute to the suppression of microglial activation. Conclusion Our findings suggest that SA plays a promising analgesic role in the BCP rats by suppressing infl ammation and microglial activation, and these effects may be associated with the suppression of p38 MAPK/c-Fos signaling.

Integrated Radial-axial Magnetic Bearing with Variable Permanent-Magnet Bias Flux In Situ

Xu Shilei,Li Jiajing,Wang Zhipeng,Sun Jinji,Ren Hongliang 대한전기학회 2024 Journal of Electrical Engineering & Technology Vol.19 No.4

Bias magnetic fl ux plays a crucial role in the performance of active magnetic bearings. However, the bias fl ux produced by NdFeB or SmCo materials in traditional permanent-magnet (PM) bias bearings cannot be adjusted, resulting in infl exible bearing performance. To improve the controllability of the PM bias fl ux in the integrated radial-axial magnetic bearing (RAMB), this article proposes a new design that uses a low coercivity AlNiCo magnet and equips a magnetization coil. By controlling the current of the magnetization coil, the magnetization state and bias fl ux of the AlNiCo magnet can be adjusted in situ, thereby improving the force characteristics and rotor iron losses of the PM-biased RAMB. The designed RAMB is analyzed and verifi ed by the 3D fi nite element method and the analytical model based on Preisach’s hysteresis theory and magnetic circuit method. The proposed design off ers a new idea for magnetic bearing structure and control.