A local solution approach for level-set based structural topology optimization in isogeometric analysis

Zijun Wu,Shuting Wang,Renbin Xiao,Lianqing Yu 한국CDE학회 2020 Journal of computational design and engineering Vol.7 No.4

This paper develops a new topology optimization approach for minimal compliance problems based on the parameterized level set method in isogeometric analysis. Here, we choose the basis functions as level set functions. The design variables are obtained with Greville abscissae based on the corresponding collocation points. The zero-level set boundaries are derived from the level set function values of the interpolation points in all knot spans. In the optimization iteration process, the whole design domain is discretized into two types of subdomains around the zero-level set boundaries, undesign area with void materials and redesign domain with solid materials. To decrease the size of equations and the computational consumptions, only the solid material area is recalculated and the void material area is discarded according to the high accuracy of isogeometric analysis. Numerical examples demonstrate the validity of the proposed optimization method.

A topology optimization approach to structure design with self-supporting constraints in additive manufacturing

Wu Zijun,Xiao Renbin 한국CDE학회 2022 Journal of computational design and engineering Vol.9 No.2

The manufacturability model of complex structure is the premise of manufacturing, and it is necessary to consider material properties, structure design, manufacturing constraints, and so on. However, due to the inconsistent restrictions between design and manufacturing, it is not easy to obtain the manufacturable structure that matches its design performance using layer-wise manufacturing. This paper presents a topology optimization method for manufacturable form, which incorporates the self-supporting factors such as overhang angle and length based on the characteristics of the generic additive manufacturing process. The support relationship between the supporting and supported elements in self-supporting constraints is mapped to a cascade relationship between two adjacent layers. To avoid a low-density structure supporting multiple high-density ingredients, we establish a fabrication model using the smax and smin operators. Also, the sensitivity analysis and variable updating method are given under the Solid Isotropic Material with Penalization method. Furthermore, numerical examples are shown to validate the correctness and superiority of this proposed self-supporting structure design method.

Vortex Domain Wall Structures and Exchange Coupled Magnetization Switching in Bit Patterned Media

Zijun Wang,Ying Zheng,Wangqiang He,Xingqiao Ma,Pingping Wu 한국자기학회 2021 Journal of Magnetics Vol.26 No.1

Establishment and validation of five autophagy-related signatures for predicting survival and immune microenvironment in glioma

Zhao Zijun,Wu Yue,Wang Zairan,Xu Jiayi,Wang Yizheng,Zhao Zongmao 한국유전학회 2022 Genes & Genomics Vol.44 No.1

Background: Gliomas, especially Glioblastoma multiforme, are the most frequent type of primary tumors in central nervous system. Increasing researches have revealed the relationship between autophagy and tumor, while the molecular mechanism of autophagy in glioma is still rarely reported. Objective: Our research aims to conform the autophagy-related genes (ARGs) implicated in the development and progression of glioma and improve our understanding of autophagy in glioma. Methods: 20 candidate ARGs were screened through the protein-protein interaction network. We also downloaded the publicly accessible glioma data for 665 individuals from TCGA and 970 individuals from CGGA with RNA sequences and clinicopathological information. Subsequently, univariate and multivariate Cox regression analysis identified 5 key ARGs among the 20 candidate genes as key prognostic genes for survival, GSEA and immune response analysis. Results: ATG5, BCL2L1, CASP3, CASP8, GAPDH were identified as key ARGs in our research. Further studies showed that the high-risk population was linked to a dismal prognosis and suggested an immune-inhibitory microenvironment. GSEA results demonstrated that high risk population was closely related to DNA repair, hypoxia pathways, implicated in immunosuppression and carcinogenesis. Through CMap, we finally identified 14 candidate drugs for the ARG high risk population. Conclusions: This study established and verified an ARG risk model, which can serve as an independent predictor for prognosis, reflect on the strength of the immune response and predict the potential drugs in glioma. Our findings offer new understandings of ARG molecular mechanism and promising therapeutic targets for glioma treatment.

Activating SIRT3 in peritoneal mesothelial cells alleviates postsurgical peritoneal adhesion formation by decreasing oxidative stress and inhibiting the NLRP3 inflammasome

Shen Tianli,Wu Yunhua,Wang Xingjie,Wang Zijun,Li Enmeng,Zhou Cancan,Yue Chenyang,Jiang Zhengdong,Wei Guangbing,Lian Jie,Xu Qinhong,Li Xuqi 생화학분자생물학회 2022 Experimental and molecular medicine Vol.54 No.-

Peritoneal adhesions (PAs) are a serious complication of abdominal surgery and negatively affect the quality of life of millions of people worldwide. However, a clear molecular mechanism and a standard therapeutic strategy for PAs have not been established. Here, we developed a standardized method to mimic the pathological changes in PAs and found that sirtuin 3 (SIRT3) expression was severely decreased in adhesion tissues, which was consistent with our bioinformatics analysis and patient adhesion tissue analysis. Thus, we hypothesized that activating SIRT3 could alleviate postsurgical PAs. Sirt3-deficient (Sirt3−/−) mice exhibited many more PAs after standardized abdominal surgery. Furthermore, compared with wild-type (Sirt3+/+) mice, Sirt3-deficient (Sirt3−/−) mice showed more prominent reactive oxygen species (ROS) accumulation, increased levels of inflammatory factors, and exacerbated mitochondrial damage and fragmentation. In addition, we observed NLRP3 inflammasome activation in the adhesion tissues of Sirt3−/− but, not Sirt3+/+ mice. Furthermore, mesothelial cells sorted from Sirt3−/− mice exhibited impaired mitochondrial bioenergetics and redox homeostasis. Honokiol (HKL), a natural compound found in several species of the genus Magnolia, could activate SIRT3 in vitro. Then, we demonstrated that treatment with HKL could reduce oxidative stress and the levels of inflammatory factors and suppress NLRP3 activation in vivo, reducing the occurrence of postsurgical PAs. In vitro treatment with HKL also restored mitochondrial bioenergetics and promoted mesothelial cell viability under oxidative stress conditions. Taken together, our findings show that the rescue of SIRT3 by HKL may be a new therapeutic strategy to alleviate and block postsurgical PA formation.

Causal relationship between smoking status, smoking frequency and bladder cancer: a Mendelian randomization study

Pang Lei,Ding Zijun,Chai Hongqiang,Li Fei,Wu Ming,Shuang Weibing 한국유전학회 2023 Genes & Genomics Vol.45 No.2

Background Smoking is a well-established risk factor for bladder cancer. However, it remained unclear that whether smoke status and smoke frequency increase bladder cancer. Objective We aim to explore the causal relationship between smoking status, smoking frequency and the risk of bladder cancer by Mendelian randomization. Methods Large sample size of the genome-wide association(GWAS) database of smoking status, smoking frequency and bladder cancer were obtained. Smoking status included never, previous and current whereas smoking frequency included cigarettes smoked per day, number of cigarettes currently smoked daily and pack years of smoking. Six sets of instrumental variables and 78 related single nucleotide polymorphic(SNP) loci were identified (P < 5 × 10–8. Linkage disequilibrium R2 < 0.001). The causal relationship between smoking status and bladder tumor was studied by inverse variance weighted (IVW), weighted median and MR-Egger regression. Sensitivity analysis were also performed. Results There is no causal effect from smoke status on bladder cancer risk while significantly positive relationship between smoking frequency on bladder cancer risk were found. IVW results showed that cigarettes smoked per day, number of cigarettes currently smoked daily and pack years of smoking increase bladder cancer (OR 1.001, 95% CI 1.000–1.002, P = 0.047; OR 1.003, 95% CI 1.000–1.005, P = 0.028; OR 1.004, 95% CI 1.001–1.006, P = 0.003). Sensitivity analysis showed that genetic pleiotropy did not bias the results. Conclusion The results of two sample Mendelian randomization analysis show that there is a positive causal relationship between smoking frequency and the risk of bladder cancer.

Vibration reduction design of the Hangzhou Bay cable-stayed bridges

Liu, Weiqing,Xu, Xiuli,Wang, Rengui,Wang, Zijun,Wu, Xiaolan Techno-Press 2006 Structural Engineering and Mechanics, An Int'l Jou Vol.24 No.3

Hangzhou Bay Bridge spans the Hangzhou Bay and is located at Zhejiang province in the southeast seacoast of China. The total length of the bridge is 36 km. The bridge is composed of bridge approaches made up of multi-span prestressed concrete box girders and two cable-stayed bridges over the north and south navigable spans respectively. The seismic response analysis of the bridge model shows that if the navigable spans are designed as the routine earthquake-resistance system, the displacements and internal forces in pylons, piers and deckes are too large to satisfy the anti-seismic requirement of the structure. Therefore, the seismic reduction design was carried out by using viscous dampers to dissipate the kinetic energy of the structure both longitudinally and transversely. Using the vibration reduction system and aiming at the reasonable optimal goal, the purpose to reduce the seismic responses in south and north navigable spans has been achieved.

Does H3K27M Mutation Impact Survival Outcome of High-Grade Spinal Cord Astrocytoma?

Fan Zhang,Lei Cheng,Ze Ding,Shengxi Wang,Xingang Zhao,Zijun Zhao,Cong Liang,Kun Wu,Dongao Zhang,Yinqian Wang,Tao Fan 대한척추신경외과학회 2023 Neurospine Vol.20 No.4

Objective: To evaluate the impact of H3K27M mutation in the prognosis of histological high-grade intramedullary astrocytoma. Methods: A total of 78 patients who were diagnosed with high-grade spinal cord astrocytoma were included. Clinical data consisting demographic, radiological, molecular features and treatment data were recorded. Univariate and multivariate Cox analysis were performed to investigate variables associated with survival outcome of histological high-grade spinal cord astrocytoma. Results: Median survival time was 21 months. Overall survival (OS) at 1 and 3 years was 65.7% and 40.7%, respectively. Sex, location, and tumor span did not present significant association with OS. Patients with H3K27M mutation showed significant shorter duration of symptom than patients with H3K27 wild-type. As respect to adjuvant treatment, adjuvant radiotherapy and chemotherapy were associated with favorable OS (both p = 0.01). Younger patients (age ≤ 18 years) had shorter OS (p = 0.008) than adult patients (age > 18 years). Of note, H3K27M mutation did not show significant impact on the survival outcome, regardless of histology grade 3 or grade 4 (p = 0.3). Conclusion: Histological high-grade spinal cord astrocytoma has dismal prognosis. Our study demonstrated that H3K27M mutation did not show significant impact on survival outcome of histological high-grade spinal cord astrocytoma.