Enzymatic Synthesis of Theanine with L-glutamine-Zn(II) Complexes

Hao-Qi Wang,Zhong Yao,Zhi Zhou,Yun Sun,Ping Wei,Ping-Kai Ouyang 한국생물공학회 2012 Biotechnology and Bioprocess Engineering Vol.17 No.6

Theanine, a unique amino acid found in tea plants, has many important physiological functions. Theanine can be enzymatically synthesized via the γ-glutamyltranspeptidation reaction. In this study, we described a new method of theanine synthesis using the L-glutamine-Zn(II)(Zn(Gln)2) complex instead of glutamine as the donor,which successfully reduced the side autotranspeptidation reaction and led to higher yield of theanine. We prepared the Zn(Gln)2 complexes and showed that they are stable in liquid bulk under 9.0 pH. After using the Zn(Gln)2 in the γ-glutamyltranspeptidation reaction, we utilized HPLC and Mass spectrometry analysis to demonstrated that Zn(Gln)2was an more effective γ-glutamyl donor than glutamine. The autotranspeptidation reaction was restrained effectively. As a result, the theanine yield and the conversion rate for glutamine were vastly improved. In a reaction mixture containing 48 mM of Zn(Gln)2, 1.6 M ethylamine, and 0.5 U/mL GGT, the final concentration of theanine obtained was 61.3 mM after incubation at 37oC for three hours. The conversion rate for glutamine was 63.8%, which showed a 16.9% increase as compared to when using glutamine alone as the donor substrate.

Electrical Measurements of an AlGaN/GaN High-electron-mobility Transistor Structure Grown on Si

Zhi-Yao Zhang,Shun-Tsung Lo,Li-Hung Lin,Kuang Yao Chen,J. Z. Huang,Zhi-Hao Sun,C.-T. Liang,N. C. Chen,Chin-An Chang,P. H. Chang 한국물리학회 2012 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.61 No.9

We report on magnetotransport results for an Al_0.15Ga_0.85N/GaN high-electron-mobility-transistor structure grown on a p-type Si (111) substrate. Our results show that there exists an approximately temperature (<i>T</i>)-independent point, which could be ascribed to a direct transition from a weak insulator to a high Landau level filling factor quantum Hall state, exists in the longitudinal resistivity ρ_xx. The Hall resistivity decreases with increasing <i>T</i>, compelling experimental evidence for electron-electron interaction effects in a weakly-disordered two-dimensional (2D) system. We find that electron-electron interaction effects can be estimated and eliminated, giving rise to a corrected nominally temperature-independent Hall slope. By fitting the low-field magnetotransport data to conventional 2D weak localization theory, we find that the dephasing rate 1/τ_φ is proportional to <i>T</i>. Moreover, 1/τ_φ is finite as <i>T</i> → 0, evidence for zero-temperature dephasing in our system.

Cisplatin Combined with Metformin Inhibits Migration and Invasion of Human Nasopharyngeal Carcinoma Cells by Regulating E-cadherin and MMP-9

Sun, Xiao-Jin,Zhang, Pei,Li, Hai-Hui,Jiang, Zhi-Wen,Jiang, Chen-Chen,Liu, Hao Asian Pacific Journal of Cancer Prevention 2014 Asian Pacific journal of cancer prevention Vol.15 No.9

Metformin has been shown to be useful in reducing insulin resistance by restoring sensitivity. Recent evidence suggests that metformin might also possess anti-tumour activity. This study aimed to investigate the effects of cisplatin combined with metformin on the proliferation, invasion and migration of HNE1/DDP human nasopharyngeal carcinoma (NPC) cells, and to provide a new target for treating metastasis. The MTT assay was used to assess viability of HNE1/DDP cells after exposure to different concentrations of 2, 5-diaminopyrimidine-4, 6-diol (DDP; 2, 4, 8, 16, and $32{\mu}mol{\cdot}L^{-1}$), metformin (5, 10, 15, 20, and $25{\mu}mol{\cdot}L^{-1}$), and $4{\mu}mol{\cdot}L^{-1}$ of DDP combined with metformin. Wound healing and transwell migration assays were performed to assess cell migration and invasion, and expression of E-cadherin and MMP-9 was detected using Western blotting. MTT assay results showed that DDP could inhibit the proliferation of HNE1/DDP cells in a time- and concentration-dependent manner, with an IC50 of $32.0{\mu}mol{\cdot}L^{-1}$ at 24 h (P < 0.05), whereas low concentrations of DDP had almost no inhibitory effects on cell invasion and migration. DDP combined with metformin significantly inhibited cell invasion and migration. In addition, genes related to migration and invasion, such as those of E-cadherin and MMP-9, showed differential expression in the NPC cell line HNE1/DDP. In the present study, with an increasing concentration of metformin, the expression of MMP-9 was downregulated whereas that of E-cadherin was significantly upregulated. Taken together, our results show that cisplatin combined with metformin has effects on proliferation, invasion, and migration of human NPC cells.

miR-10b Promotes Migration and Invasion in Nasopharyngeal Carcinoma Cells

Sun, Xiao-Jin,Liu, Hao,Zhang, Pei,Zhang, Xu-Dong,Jiang, Zhi-Wen,Jiang, Chen-Chen Asian Pacific Journal of Cancer Prevention 2013 Asian Pacific journal of cancer prevention Vol.14 No.9

MicroRNA-10b (miR-10b) has been reported to play an important role in some types of cancer, but the effects and possible mechanisms of action of miR-10b in the metastasis of nasopharyngeal carcinoma cells (NPC) have not been explored. The aim of the present study was to investigate the function of miR-10b in nasopharyngeal carcinoma and to determine the molecular mechanisms underlying its action. The MTT assay was used to assess proliferation of CNE-2Z cells. Wound healing and transwell migration assays were applied to assess cell migration and invasion, while and expression of E-cadherin and MMP-9 were detected using Western blot analysis. Real-time PCR was employed to detect the expression of genes related to migration and invasion and the $2^{-{\Delta}{\Delta}Ct}$ method was used to calculate the degree of expression. MTT assay showed the expression of miR-10b to have no effect on the proliferation of NPC cell lines. The wound healing assay showed that miR-10b mimics promoted the mobility and invasion of NPC cell lines. Inhibitors of miR-10b reduced the ability of NPC cell lines to migrate and invade. In addition, the expression of genes related to migration and invasion, such as E-cadherin, vimentin, and MMP-9, were confirmed to be different in the CNE-2Z NPC cell line transfected with miR-10b mimics and with miR-10b inhibitors. In the present study, miR-10b was found to upregulate the expression of MMP-9 and knockdown of miR-10b was found to significantly downregulate the expression of E-cadherin. On the whole, these results showed that miR-10b plays an important role in the invasion and metastasis of NPC cells.

Active mass damper control for cable stayed bridge under construction: an experimental study

Hao Chen,Zhi Sun,Limin Sun 국제구조공학회 2011 Structural Engineering and Mechanics, An Int'l Jou Vol.38 No.2

A cable stayed bridge under construction has low structural damping and is not as stable as the completed bridge. Control countermeasures, such as the installation of energy dissipating devices, are thus required. In this study, the general procedure and key issues on adopting an active control device, the active mass damper (AMD), for vibration control of cable stayed bridges under construction were studied. Taking a typical cable stayed bridge as the prototype structure; a lab-scale test structure was designed and fabricated firstly. A baseline FEM model was then setup and updated according to the modal parameters measured from vibration test on the structure. A numerical study to simulate the bridge-AMD control system was conducted and an efficient LQG-based controller was designed. Based on that, an experimental implementation of AMD control of the transverse vibration of the bridge model was performed. The results from numerical simulation and experimental study verified that the AMD-based active control was feasible and efficient for reducing dynamic responses of a complex structural system. Moreover, the discussion made in this study clarified some critical problems which should be addressed for the practical implementation of AMD control on real cable-stayed bridges.

Current Evidence on the Relationship Between Two Polymorphisms in the NBS1 Gene and Breast Cancer Risk: a Meta-analysis

Zhang, Zhi-Hua,Yang, Lin-Sheng,Huang, Fen,Hao, Jia-Hu,Su, Pu-Yu,Sun, Ye-Huan Asian Pacific Journal of Cancer Prevention 2012 Asian Pacific journal of cancer prevention Vol.13 No.11

Introduction: Published studies on the association between Nijmegen breakage syndrome 1(NBS1) gene polymorphisms and breast cancer risk have been inconclusive, and a meta-analysis was therefore performed for clarification. Methods: Eligible articles were identified by a search of MEDLINE and EMBASE bibliographic databases for the period up to March 2012. The presence of between-study heterogeneity was investigated using the chi-square-based Cochran's Q statistic test. When there was statistical heterogeneity, the random effects model was chosen; otherwise, fixed effects estimates were reported as an alternative approach. Results: A total of 11 eligible articles (14 case-control studies) were identified, nine case-control studies were for the 657del5 mutation (7,534 breast cancer cases, 14,034 controls) and five case-control studies were for the I171V mutation (3,273 breast cancer cases, 4,004 controls). Our analysis results indicated that the 657del5 mutation was associated with breast cancer risk (carriers vs. non-carriers: pooled OR =2.63, 95% CI: 1.76-3.93), whereas the I171V mutation was not (carriers vs. non-carriers: pooled OR =1.52, 95% CI: 0.70-3.28). Conclusion: The present meta-analysis suggests that the 657del5 gene mutation in the NBS1 gene plays a role in breast cancer risk, while the I171V mutation does not exert a significant influence.

Predictive Significance of Claudin-3 for Epithelial Barrier Dysfunction in Chronic Rhinosinusitis With Nasal Polyps

Huang Zhi-Qun,Ye Jing,Liu Jing,Sun Li-Ying,Ong Hsiao Hui,Wei Yong-Hao,Fu Shu-Cai,Hu Xiao-Xun,Xu Yu,Wang De-Yun 대한천식알레르기학회 2023 Allergy, Asthma & Immunology Research Vol.15 No.4

Purpose: The abnormal expression of tight junction (TJ) plays a vital role in the pathogenesis of chronic rhinosinusitis with nasal polyps (CRSwNP). However, there is no appropriate tool to distinguish and diagnose epithelial barrier defects in clinical practice. This study aimed to evaluate the predictive value of claudin-3 for epithelial barrier dysfunction in CRSwNP. Methods: In this study, TJ protein levels were evaluated by real-time quantitative polymerase chain reaction, immunofluorescent, and immunohistochemistry staining in control subjects and CRSwNP patients. The receiver operating characteristic (ROC) curve was created to assess the predictive value of TJ breakdown in clinical outcomes. In vitro, human nasal epithelial cells were cultured at the air-liquid interface to analyze the transepithelial electrical resistance (TER) level. Results: The expression levels of occludin, tricellulin, claudin-3, and claudin-10 were decreased (all P < 0.05), and those of claudin-1 was increased (P < 0.05) in CRSwNP patients as compared to healthy subjects. Additionally, claudin-3 and occludin levels were negatively correlated with the computed tomography score in CRSwNP (all P < 0.05), and the ROC curve indicated that the claudin-3 level had the most predictive accuracy in evaluating epithelial barrier disruption (area under the curve = 0.791, P < 0.001). Finally, the time-series analysis showed the highest correlation coefficient between TER and claudin-3 (cross-correlation function = 0.75). Conclusion: In this study, we suggest that claudin-3 could be a valuable biomarker for predicting nasal epithelial barrier defects and disease severity in CRSwNP.

Experimental quantum fast hitting on hexagonal graphs

Tang, Hao,Di Franco, Carlo,Shi, Zi-Yu,He, Tian-Shen,Feng, Zhen,Gao, Jun,Sun, Ke,Li, Zhan-Ming,Jiao, Zhi-Qiang,Wang, Tian-Yu,Kim, M. S.,Jin, Xian-Min Springer Science and Business Media LLC 2018 Nature photonics Vol.12 No.12

Effect of Sand Particle Size on Hydraulic-Mechanical Behavior of Bentonite-Sand Mixtures

Tian-Hao Lu,Wen-Jing Sun,Ke Liu,Yun-Zhi Tan 대한토목학회 2022 KSCE JOURNAL OF CIVIL ENGINEERING Vol.26 No.8

Bentonite-sand mixtures can be used as the base material of engineered barriers in deep high-level radioactive waste geological repositories. Swelling, compression, and permeability tests were conducted out on bentonite-sand mixtures with 30%, 50%, 70% and 85% sand content. Influence of sand content and particle size on the deformation and permeability characteristics of bentonite-sand mixtures were analyzed. The sand particle size affects the deformation characteristics by influencing the vertical stress required to form a sand skeleton, and the skeleton’s stability. When the sand content is less than the critical sand content, bentonite-sand mixtures cannot form a sand skeleton, and particle size has no effect on their characteristics. When the sand content is greater than the critical sand content and the vertical stress exceeds the initial deviation stress, a sand skeleton forms. In this case, smaller the sand particle size, lesser will be the vertical stress required to form a sand skeleton, and more the swelling of bentonite-sand mixtures. Further, more uniform particle size, more stable will be its structure and lesser the compressibility of bentonite-sand mixtures. The hydraulic conductivity is related to the flow area and the seepage path length, and particle size has no obvious effect on either with the same sand content. Therefore, the sand particle size has no obvious effect on mixtures’ permeability.

Active mass damper control for cable stayed bridge under construction: an experimental study

Chen, Hao,Sun, Zhi,Sun, Limin Techno-Press 2011 Structural Engineering and Mechanics, An Int'l Jou Vol.38 No.2

A cable stayed bridge under construction has low structural damping and is not as stable as the completed bridge. Control countermeasures, such as the installation of energy dissipating devices, are thus required. In this study, the general procedure and key issues on adopting an active control device, the active mass damper (AMD), for vibration control of cable stayed bridges under construction were studied. Taking a typical cable stayed bridge as the prototype structure; a lab-scale test structure was designed and fabricated firstly. A baseline FEM model was then setup and updated according to the modal parameters measured from vibration test on the structure. A numerical study to simulate the bridge-AMD control system was conducted and an efficient LQG-based controller was designed. Based on that, an experimental implementation of AMD control of the transverse vibration of the bridge model was performed. The results from numerical simulation and experimental study verified that the AMD-based active control was feasible and efficient for reducing dynamic responses of a complex structural system. Moreover, the discussion made in this study clarified some critical problems which should be addressed for the practical implementation of AMD control on real cable-stayed bridges.