Parametric pitch instability investigation of Deep Draft Semi-submersible platform in irregular waves

Mao, Huan,Yang, Hezhen The Society of Naval Architects of Korea 2016 International Journal of Naval Architecture and Oc Vol.8 No.1

Parametric pitch instability of a Deep Draft Semi-submersible platform (DDS) is investigated in irregular waves. Parametric pitch is a form of parametric instability, which occurs when parameters of a system vary with time and the variation satisfies a certain condition. In previous studies, analyzing of parametric instability is mainly limited to regular waves, whereas the realistic sea conditions are irregular waves. Besides, parametric instability also occurs in irregular waves in some experiments. This study predicts parametric pitch of a Deep Draft Semi-submersible platform in irregular waves. Heave motion of DDS is simulated by wave spectrum and response amplitude operator (RAO). Then Hill equation for DDS pitch motion in irregular waves is derived based on linear-wave theory. By using Bubnov-Galerkin approach to solve Hill equation, the corresponding stability chart is obtained. The differences between regular-waves stability chart and irregular-waves stability chart are compared. Then the sensitivity of wave parameters on DDS parametric pitch in irregular waves is discussed. Based on the discussion, some suggestions for the DDS design are proposed to avoid parametric pitch by choosing appropriate parameters. The results indicate that it's important and necessary to predict DDS parametric pitch in irregular waves during design process.

Parametric pitch instability investigation of Deep Draft Semi-submersible platform in irregular waves

Huan Mao,He-zhen Yang 대한조선학회 2016 International Journal of Naval Architecture and Oc Vol.8 No.1

Parametric pitch instability of a Deep Draft Semi-submersible platform (DDS) is investigated in irregular waves. Parametric pitch is a form of parametric instability, which occurs when parameters of a system vary with time and the variation satisfies a certain condition. In previous studies, analyzing of parametric instability is mainly limited to regular waves, whereas the realistic sea conditions are irregular waves. Besides, parametric instability also occurs in irregular waves in some experiments. This study predicts parametric pitch of a Deep Draft Semi-submersible platform in irregular waves. Heave motion of DDS is simulated by wave spectrum and response amplitude operator (RAO). Then Hill equation for DDS pitch motion in irregular waves is derived based on linear-wave theory. By using Bubnov-Galerkin approach to solve Hill equation, the corresponding stability chart is obtained. The differences between regular-waves stability chart and irregular-waves stability chart are compared. Then the sensitivity of wave parameters on DDS parametric pitch in irregular waves is discussed. Based on the discussion, some suggestions for the DDS design are proposed to avoid parametric pitch by choosing appropriate parameters. The results indicate that it's important and necessary to predict DDS parametric pitch in irregular waves during design process.

Highly heat-resistant NF membrane modified by quinoxaline diamines for Li+ extraction from the brine

Huan-Yin Xie,Run-Hua Tang,Gui-E Chen,Zhen-Liang Xu,Haifang Mao 한국공업화학회 2022 Journal of Industrial and Engineering Chemistry Vol.112 No.-

The Functional layers with excellent heat-resistence nanofiltration (HRN) property were designed by fixingthermal stabilized quinoxaline diamines (QHDA) on poly (m-phenyleneisophthalamide) (PMIA) substratethrough interfacial polymerization. QHDA was used as aqueous monomer while cinnamoylchloride (CNC), isophthaloyl chloride (IPC) and trimesoyl chloride (TMC) were served as organic monomersto realize the immobilization of thermally stable N heterocycles. The experimental results statedclearly that the compact package reaction of QHDA with TMC lead a raise of thermal stability and saltsrejection at high temperature stream. With the optimal TMC and 0.5 wt.% QHDA, the as-developed membraneachieved the excellent NF performance and thermal stability. The rejection of MgSO4 reached to94.6 % at 30 C and hardly decrease at 90 C. The reduction in rejection was satisfactory at high temperatures. The functional layer still showed highly stability after 10 h long-term operation at 90 C with only2.8 % reduction in MgSO4 rejection. Besides, the excellent Mg2+ and poor Li+ rejection made this membranehave huge potential in the application of extracting Li+ from brine. The separation factor ofMg2+-Li+ at high temperature was satisfactory. Over all, this study offered a prospect technology toexploit heat-resistant membranes for extraction lithium at high temperature.

Prime ideals and maximal ideals on commutative $L$-algebras

Huan Yun,Xiao Long Xin,Xiao Fei Yang,Ling Ling Mao 원광대학교 기초자연과학연구소 2024 ANNALS OF FUZZY MATHEMATICS AND INFORMATICS Vol.27 No.1

In this paper, we focus on ideals and prime ideals of $CKL$-algebras and applications of prime ideals of $CKL$-algebras. Firstly, we prove that any self-distributive $L$-algebra is a $CKL$-algebra. Conversely, we give an example of $CKL$-algebras that is not a self-distributive $L$-algebra. Furthermore, we give a generation formula of ideals on $CKL$-algebras. Secondly, we give some equivalent descriptions of prime ideals and its properties on $CKL$-algebras. We mainly prove that maximal ideals are prime ideals on $CKL$-algebras. Next, we give a counterexample to show that commutative L-algebras may be not residuated lattices, much less $MV$-algebras. The results show that commutative L-algebras are a true promotion of $MV$-algebras. Therefore, we study some properties of commutative $L$-algebras.

Relationships among MTHFR a1298c Gene Polymorphisms and Methylation Status of Dact1 Gene in Transitional Cell Carcinomas

Cheng, Huan,Lu, Meng,Mao, Li-Jun,Wang, Jun-Qi,Li, Wang,Wen, Ru-Min,Chen, Jia-Cun Asian Pacific Journal of Cancer Prevention 2012 Asian Pacific journal of cancer prevention Vol.13 No.10

Objectives: The purpose of this study was to determine the relationship between methylation status of the Dact1 gene and MTHFR a1298c polymorphic forms in transitional cell carcinoma tissues in a Chinese population. Methods: Polymorphisms of folate metabolism enzyme gene MTHFR were assessed by restrictive fragment length polymorphism (RFLP) methods and PCR-based DNA methylation analysis was used to determine the CpG island methylation status of the Dact1 gene. Associations between the methylation status of the Dact1 gene and clinical characteristics, as well as MTHFR a1298c polymorphisms, were analyzed. Results: aberrant methylation of the Dact1 gene was found in 68.3% of cancer tissues and 12.4% of normal tissues,. The methylation rate of the Dact1 gene in cancer tissues was significantly higher in patients with lymph node metastasis than in those without lymph node metastasis (46.3% vs. 17.2%, P = 0.018). No association was found between aberrant DNA methylation and selected factors including sex, age, tobacco smoking, alcohol consumption and green tea consumption. After adjusting for potential confounding variables, variant allele of MTHFR a1298c was found to be associated with methylation of the Dact1 gene. Compared with wild type CC, the odds ratio was 4.33 (95% CI: 1.06-10.59) for AC and 4.95 (95% CI: 1.18-12.74) for AA. The N stage in TNM staging and the occurrence of lymph node metastasis were associated with an MTHFR 1298 AA+AC genotype (P<0.05). Conclusion: MTHFR 1298 AC and AA genotypes might help maintain a normal methylation status of the Dact1 gene, aberrant CpG island methylation of which is closely related to the genesis and progression of transitional cell carcinoma.

Metformin Down-regulates Endometrial Carcinoma Cell Secretion of IGF-1 and Expression of IGF-1R

Zhang, Yu,Li, Meng-Xiong,Wang, Huan,Zeng, Zheng,Li, Xiao-Mao Asian Pacific Journal of Cancer Prevention 2015 Asian Pacific journal of cancer prevention Vol.16 No.1

As metformin can inhibit endometrial carcinoma (EC) cell growth and the insulin growth factor (IGF) system is active in EC, the question of whether it can regulate endometrial carcinoma cell secretion of IGF-1 or expression of IGF-1 receptor (IGF-1R) is of interest. In this study, serum IGF-1 levels in EC patients were found to be comparable with that in the non EC patients (p>0.05). However, the IGF-1 level in the medium of cultured cells after treatment with metformin was decreased (p<0.05). IGF-1R was highly expressed in human endometrial carcinoma paraffin sections, but IGF-1R and phosphor-protein kinase B/protein kinase B (p-Akt/Akt) expression was down-regulated after metformin treatment (p<0.05). In summary, metformin can reduce the secretion of IGF-1 by Ishikawa and JEC EC cell lines and their expression of IGF-1R to deactivate downstream signaling involving the PI-3K/Akt pathway to inhibit endometrial carcinoma cell growth.

Wnt pathway is involved in 5-FU drug resistance of colorectal cancer cells

Lingfeng He,Hong Zhu,Shiying Zhou,Ting Wu,Huan Wu,Huan Yang,Huiwen Mao,Chandra SekharKathera,Avilala Janardhan,Ashlin M. Edick,Anna Zhang,Zhigang Hu,Feiyan Pan,Zhigang Guo 생화학분자생물학회 2018 Experimental and molecular medicine Vol.50 No.-

Colorectal cancer (CRC) is one of the leading causes of cancer-related death worldwide. 5-Fluorouracil (5-FU) is widely used in the treatment of cancers, but its antineoplastic activity is limited in drug-resistant cancer cells. To investigate the detailed mechanism of 5-FU resistance, we developed a model of 5-FU-resistant cells from HCT-8 cells, a wellestablished colorectal cancer cell line. We found that the drug-resistant cells demonstrated high expression of TCF4 and β-catenin, indicating an upregulated Wnt pathway. A microarray analysis revealed that the suppression of the checkpoint kinase 1 (CHK1) pathway explained the resistance to 5-FU, especially in p53 wild-type cancer cells such as HCT-8. Our data also demonstrated that the CHK1 pathway is suppressed by the Wnt pathway in 5-FU-resistant cells. In summary, we have discovered a novel mechanism for 5-FU resistance mediated by histone deacetylation, which also revealed the crosstalk between the Wnt pathway and CHK1 pathway.

Inhibitory effects of piceatannol on human cytomegalovirus (hCMV) in vitro

Wang San-Ying,Zhang Jing,Xu Xiao-Gang,Su Hui-Li,Xing Wen-Min,Zhang Zhong-Shan,Jin Wei-Hua,Dai Ji-Huan,Wang Ya-Zhen,He Xin-Yue,Sun Chuan,Yan Jing,Mao Gen-Xiang 한국미생물학회 2020 The journal of microbiology Vol.58 No.8

Human cytomegalovirus (hCMV) is a ubiquitous herpesvirus, which results in the establishment of a latent infection that persists throughout the life of the host and can be reactivated when the immunity is low. Currently, there is no vaccine for hCMV infection, and the licensed antiviral drugs mainly target the viral enzymes and have obvious adverse reactions. Thus, it is important to search for compounds with antihCMV properties. The present study aimed to investigate the suppressive effects of piceatannol on hCMV Towne strain infection and the putative underlying mechanisms using human diploid fibroblast WI-38 cells. Piceatannol supplementation prevented the lytic changes induced by hCMV infection in WI-38 cells. Furthermore, piceatannol suppressed the expression of hCMV immediate-early (IE) and early (E) proteins as well as the replication of hCMV DNA in a dose-dependent manner. Moreover, hCMV-induced cellular senescence was suppressed by piceatannol, as shown by a decline in the senescence-associated β-galactosidase (SA-β-Gal) activity and decreased production of intracellular reactive oxygen species (ROS). p16INK4a, a major senescence-associated molecule, was dramatically elevated by current hCMV infection that was attenuated by pre-incubation with piceatannol in a dose-dependent manner. These results demonstrated that piceatannol suppressed the hCMV infection via inhibition of the activation of p16INK4a and cellular senescence induced by hCMV. Together, these findings indicate piceatannol as a novel and potent anti-hCMV agent with the potential to be developed as an effective treatment for chronic hCMV infection.