Investigation of the behavior of a crack between two half-planes of functionally graded materials by using the Schmidt method

Zhen-Gong Zhou,Biao Wang,Lin-Zhi Wu 국제구조공학회 2005 Structural Engineering and Mechanics, An Int'l Jou Vol.19 No.4

In this paper, the behavior of a crack between two half-planes of functionally graded materials subjected to arbitrary tractions is resolved using a somewhat different approach, named the Schmidt method. To make the analysis tractable, it is assumed that the Poisson’s ratios of the mediums are constants and the shear modulus vary exponentially with coordinate parallel to the crack. By use of the Fourier transform, the problem can be solved with the help of two pairs of dual integral equations in which the unknown variables are the jumps of the displacements across the crack surfaces. To solve the dual integral equations, the jumps of the displacements across the crack surfaces are expanded in a series of Jacobi polynomials. This process is quite different from those adopted in previous works. Numerical examples are provided to show the effect of the crack length and the parameters describing the functionally graded materials upon the stress intensity factor of the crack. It can be shown that the results of the present paper are the same as ones of the same problem that was solved by the singular integral equation method. As a special case, when the material properties are not continuous through the crack line, an approximate solution of the interface crack problem is also given under the assumption that the effect of the crack surface interference very near the crack tips is negligible. It is found that the stress singularities of the present interface crack solution are the same as ones of the ordinary crack in homogenous materials.

The nonlocal theory solution for two collinear cracks in functionally graded materials subjected to the harmonic elastic anti-plane shear waves

Zhou, Zhen-Gong,Wang, Biao Techno-Press 2006 Structural Engineering and Mechanics, An Int'l Jou Vol.23 No.1

In this paper, the scattering of harmonic elastic anti-plane shear waves by two collinear cracks in functionally graded materials is investigated by means of nonlocal theory. The traditional concepts of the non-local theory are extended to solve the fracture problem of functionally graded materials. To overcome the mathematical difficulties, a one-dimensional non-local kernel is used instead of a two-dimensional one for the anti-plane dynamic problem to obtain the stress field near the crack tips. To make the analysis tractable, it is assumed that the shear modulus and the material density vary exponentially with coordinate vertical to the crack. By use of the Fourier transform, the problem can be solved with the help of a pair of triple integral equations, in which the unknown variable is the displacement on the crack surfaces. To solve the triple integral equations, the displacement on the crack surfaces is expanded in a series of Jacobi polynomials. Unlike the classical elasticity solutions, it is found that no stress singularities are present at crack tips.

Two collinear Mode-I cracks in piezoelectric/piezomagnetic materials

Zhou, Zhen-Gong,Wang, Jia-Zhi,Wu, Lin-Zhi Techno-Press 2008 Structural Engineering and Mechanics, An Int'l Jou Vol.29 No.1

In this paper, the behavior of two collinear Mode-I cracks in piezoelectric/piezomagnetic materials subjected to a uniform tension loading was investigated by the generalized Almansi's theorem. Through the Fourier transform, the problem can be solved with the help of two pairs of triple integral equations, in which the unknown variables were the jumps of displacements across the crack surfaces. To solve the triple integral equations, the jumps of displacements across the crack surfaces were directly expanded as a series of Jacobi polynomials to obtain the relations among the electric displacement intensity factors, the magnetic flux intensity factors and the stress intensity factors at the crack tips. The interaction of two collinear cracks was also discussed in the present paper.

Investigation of the behavior of a crack between two half-planes of functionally graded materials by using the Schmidt method

Zhou, Zhen-Gong,Wang, Biao,Wu, Lin-Zhi Techno-Press 2005 Structural Engineering and Mechanics, An Int'l Jou Vol.19 No.4

In this paper, the behavior of a crack between two half-planes of functionally graded materials subjected to arbitrary tractions is resolved using a somewhat different approach, named the Schmidt method. To make the analysis tractable, it is assumed that the Poisson's ratios of the mediums are constants and the shear modulus vary exponentially with coordinate parallel to the crack. By use of the Fourier transform, the problem can be solved with the help of two pairs of dual integral equations in which the unknown variables are the jumps of the displacements across the crack surfaces. To solve the dual integral equations, the jumps of the displacements across the crack surfaces are expanded in a series of Jacobi polynomials. This process is quite different from those adopted in previous works. Numerical examples are provided to show the effect of the crack length and the parameters describing the functionally graded materials upon the stress intensity factor of the crack. It can be shown that the results of the present paper are the same as ones of the same problem that was solved by the singular integral equation method. As a special case, when the material properties are not continuous through the crack line, an approximate solution of the interface crack problem is also given under the assumption that the effect of the crack surface interference very near the crack tips is negligible. It is found that the stress singularities of the present interface crack solution are the same as ones of the ordinary crack in homogenous materials.

Two collinear Mode-I cracks in piezoelectric/piezomagnetic materials

Zhen-Gong Zhou,Jia-Zhi Wang,Lin-Zhi Wu 국제구조공학회 2008 Structural Engineering and Mechanics, An Int'l Jou Vol.29 No.1

In this paper, the behavior of two collinear Mode-I cracks in piezoelectric/piezomagnetic materials subjected to a uniform tension loading was investigated by the generalized Almansi’s theorem. Through the Fourier transform, the problem can be solved with the help of two pairs of triple integral equations, in which the unknown variables were the jumps of displacements across the crack surfaces. To solve the triple integral equations, the jumps of displacements across the crack surfaces were directly expanded as a series of Jacobi polynomials to obtain the relations among the electric displacement intensity factors, the magnetic flux intensity factors and the stress intensity factors at the crack tips. The interaction of two collinear cracks was also discussed in the present paper.

Aberrant Expression of Markers of Cancer Stem Cells in Gastric Adenocarcinoma and their Relationship to Vasculogenic Mimicry

Zhou, Lei,Yu, Lan,Feng, Zhen-Zhong,Gong, Xiao-Meng,Cheng, Ze-Nong,Yao, Nan,Wang, Dan-Na,Wu, Shi-Wu Asian Pacific Journal of Cancer Prevention 2015 Asian Pacific journal of cancer prevention Vol.16 No.10

Background: Gastric cancer is the second leading cause of cancer-related death in Asia, and the majority type is gastric adenocarcinoma (GAC). Most GAC patients die of recurrence and metastasis. Cancer stem cells (CSCs) have been thought to be responsible for the initiation, development, metastasis, and ultimately recurrence of cancer. In this study, we aimed to investigate expression and clinical significance of CSCs markers, CD133 and Lgr5, and vasculogenic mimicry (VM) in primary GAC. Materials and Methods: Specimens from 261 Chinese patients with follow-up were analyzed for CD133, Lgr5 protein expression and VM by immunohistochemical and histochemical staining. The Pearson Chi's square test was used to assess the associations among the positive staining of these markers and clinicopathological characteristics. Postoperative overall survival time was were studied by univariate and multivariate analyses. Results: In GAC tissues, positive rates of 49.0%, 38.7%, and 26.8% were obtained for CD133, Lgr5, and VM, respectively. The mean score of microvessel density (MVD) was $21.7{\pm}11.1$ in GAC tissues. There was a significantly difference between the positive and negative groups. There was a positive relationship between the VM, the expression of CD133 and Lgr5, and the score of MVD and the grades of tumor, lymph node metastasis, TNM stages (all p<0.05). The overall mean survival time of the patients with CD133, Lgr5, VM, and MVD (${\geq}22$) positive expression was lower than that of patients with negative expression. The score of MVD, positive expression of CD133 and VM were independent prognostic factors of GAC (p<0.05). Conclusions: VM, and expression of CD133, Lgr5, and the score of MVD are related to grades of tumor, lymph node metastasis, TNM stages, and overall mean survival time. It is suggested that CSCs and VM could play an important role in the evolution of GAC.

Transcriptional regulation of Glis2 in hepatic fibrosis

Gong Huan-Yu,Zhou Peng-Cheng,Zhang Hao-Ye,Chen Li-Min,Zhou Yang-Mei,Liu Zhen-Guo 생화학분자생물학회 2023 Experimental and molecular medicine Vol.55 No.-

The role of Gli-similar 2 (Glis2) in hepatic fibrosis (HF) is controversial. In this study, we focused on the functional and molecular mechanisms involved in the Glis2-mediated activation of hepatic stellate cells (HSCs)—a milestone event leading to HF. The expression levels of Glis2 mRNA and protein were significantly decreased in the liver tissues of patients with severe HF and in mouse fibrotic liver tissues as well as HSCs activated by TGFβ1. Functional studies indicated that upregulated Glis2 significantly inhibited HSC activation and alleviated BDL-induced HF in mice. Downregulation of Glis2 was found to correlate significantly with DNA methylation of the Glis2 promoter mediated by methyltransferase 1 (DNMT1), which restricted the binding of hepatic nuclear factor 1-α (HNF1-α), a liver-specific transcription factor, to Glis2 promoters. In addition, the enrichment of DNMT1 in the Glis2 promoter region was mediated by metastasis-associated lung adenocarcinoma transcriptor-1 (MALAT1) lncRNA, leading to transcriptional silencing of Glis2 and activation of HSCs. In conclusion, our findings reveal that the upregulation of Glis2 can maintain the resting state of HSCs. The decreased expression of Glis2 under pathological conditions may lead to the occurrence and development of HF with the expression silencing of DNA methylation mediated by MALAT1 and DNMT1.

New Method to Improve the Secondary Path Modeling Accuracy for Active Noise Control Systems

Shan-zhen Yi,Ren-yuan Fei,Da-sen Zhou,Tai-wen Liu,Jian-ping Yu,Jin-feng Yang,Kui-cheng Gong 한국소음진동공학회 2003 한국소음진동공학회 국제학술대회논문집 Vol.2003 No.8

Nitrogen, phosphorus and potassium fertilization promotes Zanthoxylum armatum ‘Hanyuan Putao Qingjiao’ fl ower bud diff erentiation in Sichuan, China

Chaobin Zhou,Yu Cai,Zhen’an Yang,Hongmin Wang,Fang Deng,Zeping Bai,Wei Gong,Jingyan Wang 한국원예학회 2020 Horticulture, Environment, and Biotechnology Vol.61 No.4

Chinese prickly ash is an ecologically and economically important tree species. In southwestern China, its yield is low dueto severe fruit and fl ower drop related to the relatively low nutrient status of shoots and/or fl owers caused by a lack of nutrientsupply. Therefore, studies on fl ower bud diff erentiation are of great importance to improve the yield of Chinese pricklyash. An orthogonal experimental design was used to study the eff ects of N (urea, 97.8, 195.7 and 391.3 g/individual), P(superphosphate, 150, 300 and 600 g/individual) and K (potassium sulphate, 83.3, 166.7 and 333.3 g/individual) treatmentson fl ower bud diff erentiation in 3-year-old Zanthoxylum armatum ‘Hanyuan Putao Qingjiao’ trees. The results showed thatN, P and K fertilizer application signifi cantly increased the fl ower bud diff erentiation rate, branch diameter and number, thesoluble sugar content, the soluble protein content, the C/N ratio, the ABA content and the ABA/IAA ratio but decreasedthe GA content and IAA content in Chinese prickly ash. The fl ower bud diff erentiation rate was positively related to thesoluble sugar content, soluble protein content, C/N ratio and ABA/IAA ratio ( p < 0.05) but negatively related to GA andIAA ( p < 0.05). A higher P content increased the accumulation of nutrients and ABA in the buds, thereby promoting thefl ower bud diff erentiation in Z. armatum ‘Hanyuan Putao Qingjiao’. From these results, the fl ower bud diff erentiation in Z. armatum ‘Hanyuan Putao Qingjiao’ requires appropriate N, P and K fertilizer ratios and amounts. Treatment 12 (N 2 P 3 K 1 )signifi cantly improved the absorption of nutrients in the buds and promoted the diff erentiation of fl ower buds.

MicroRNA-766-3p Inhibits Tumour Progression by Targeting Wnt3a in Hepatocellular Carcinoma

You, Yu,Que, Keting,Zhou, Yun,Zhang, Zhen,Zhao, Xiaoping,Gong, Jianpin,Liu, Zuojin Korean Society for Molecular and Cellular Biology 2018 Molecules and cells Vol.41 No.9

Recent studies have indicated that microRNAs (miRNAs) play an important role in hepatocellular carcinoma (HCC) progression. In this study, we showed that miR-766-3p was decreased in approximately 72% of HCC tissues and cell lines, and its low expression level was significantly correlated with tumour size, TNM stage, metastasis, and poor prognosis in HCC. Ectopic miR-766-3p expression inhibited HCC cell proliferation, colony formation, migration and invasion. In addition, we showed that miR-766-3p repressed Wnt3a expression. A luciferase reporter assay revealed that Wnt3a was a direct target of miR-766-3p, and an inverse correlation between miR-766-3p and Wnt3a expression was observed. Moreover, Wnt3a up-regulation reversed the effects of miR766-3p on HCC progression. In addition, our study showed that miR-766-3p up-regulation decreased the nuclear ${\beta}-catenin$ level and expression of Wnt targets (TCF1 and Survivin) and reduced the level of MAP protein regulator of cytokinesis 1 (PRC1). However, these effects of miR-766-3p were reversed by Wnt3a up-regulation. In addition, PRC1 upregulation increased the nuclear ${\beta}-catenin$ level and protein expression of TCF1 and Survivin. iCRT3, which disrupts the ${\beta}-catenin-TCF4$ interaction, repressed the TCF1, Survivin and PRC1 protein levels. Taken together, our results suggest that miR-766-3p down-regulation promotes HCC cell progression, probably by targeting the Wnt3a/PRC1 pathway, and miR-766-3p may serve as a potential therapeutic target in HCC.