Expression, Purification and Properties of Shikimate Dehydrogenasefrom Mycobacterium Tuberculosis

Xuhui Lai,Honghai Wang,Xuelian Zhang,Shunbao Zhang,Fang Hao,Haidong Yu,Yishu Huang 한국생화학분자생물학회 2005 BMB Reports Vol.38 No.5

Study on the effect of vacuum fusion infiltration technology on the properties of tungsten/copper joining interface

Zhang Hao-Jie,Tian Xue-qin,Ding Xiao-Yu,Zheng Hui-Yun,Luo Lai-Ma,Wu Yu-Cheng,Yao Jian-Hua 한국원자력학회 2024 Nuclear Engineering and Technology Vol.56 No.6

In this paper, based on the need for high-strength connections between all-tungsten-oriented plasma materials and thermal sinking materials of copper and its alloys in nuclear fusion devices, a study on the effect of tungsten surface laser micro structuring on the interfacial bonding properties of W/Cu joints was carried out. In the experiment, the connectors were prepared by vacuum fusion infiltration technology, and the effects of microgroove structure on the mechanical and thermal conductivity of W/Cu connectors were investigated under different parameters (including microgroove pitch, microgroove depth, and microgroove taper). The maximum shear strength is 126.0 MPa when the pitch is 0.15 mm and the depth is 34 μm. In addition, the negative taper structure, i.e., the width of the entrance of the microstructure is smaller than the width of the interior of the microstructure, is also investigated. The shear tests show that there is an approximately linear relationship between the shear strength of W/Cu and taper. Compared with the positive taper, the shear strength of the samples with the same morphological density and depth of the tungsten surface is significantly higher.

Maintenance of pegylated liposomal doxorubicin/carboplatin in patients with advanced ovarian cancer: randomized study of an Asian Gynecologic Oncology Group

Chyong-Huey Lai,Elizabeth Vallikad,Hao Lin,Lan-Yan Yang,Shih-Ming Jung,Hsueh-Erh Liu,Yu-Che Ou,Hung-Hsueh Chou,Cheng-Tao Lin,Huei-Jean Huang,Kuan-Gen Huang,Jiantai Qiu,Yao-Ching Hung,Tzu-I Wu,Wei-Yang 대한부인종양학회 2020 Journal of Gynecologic Oncology Vol.31 No.1

Objectives: An Asian Gynecologic Oncology Group phase III randomized trial was conducted to determine whether maintenance chemotherapy could improve progression-free survival (PFS) in stages III/IV ovarian cancer. Methods: Between 2007 and 2014, 45 newly-diagnosed ovarian cancer patients were enrolled after complete remission and randomized (1:1) to arm A (4-weekly carboplatin area under the curve 4 and pegylated liposomal doxorubicin [PLD] 30 mg/m2, n=24) for 6 cycles or arm B (observation, n=21). The primary end-point was PFS. A post hoc translational study was conducted to deep sequence BRCA/homologous recombination deficiency (HRD) genes, because BRCA/HRD mutations (BRCA/HRDm) are known to be associated with better prognosis. Results: Enrollment was slow, accrual was closed when 7+ years had passed. With a median follow-up of 88.9 months, the median PFS was significantly better in arm A (55.5 months) than arm B (9.2 months) (hazard ratio [HR]=0.40; 95% confidence interval [CI]=0.19–0.87; p=0.020), yet the median overall survival was not significantly different in arm A (not reached) than arm B (95.1 months) (p=0.148). Overall grade 3/4 adverse events were more frequent in arm A than arm B (60.9% vs 0.0%) (p<0.001). Quality of life was generally not significantly different. Distribution of BRCA1/2m or BRCA/HRDm was not significantly biased between the two arms. Wild-type BRCA/non-HRD subgroup seemed to fare better with maintenance therapy (HR=0.35; 95% CI=0.11–1.18; p=0.091). Conclusions: Despite limitations in small sample size, it suggests that maintenance carboplatin-PLD chemotherapy could improve PFS in advanced ovarian cancer.

Expression, Purification and Properties of Shikimate Dehydrogenase from Mycobacterium Tuberculosis

Zhang, Xuelian,Zhang, Shunbao,Hao, Fang,Lai, Xuhui,Yu, Haidong,Huang, Yishu,Wang, Honghai Korean Society for Biochemistry and Molecular Biol 2005 Journal of biochemistry and molecular biology Vol.38 No.5

Tuberculosis, caused by Mycobacterium tuberculosis, continues to be one of the main diseases to mankind. It is urgent to discover novel drug targets for appropriate antimicrobial agents against this human pathogen. The shikimate pathway is onsidered as an attractive target for the discovery of novel antibiotics for its essentiality in bacteria and absence in mammalian cells. The Mycobacterium tuberculosis aroE-encoded shikimate dehydrogenase was cloned, expressed and purified. Sequence alignment analysis shows that shikimate dehydrogenase of Mycobacterium tuberculosis exhibit the pattern of G-X-(N/S)-V-(T/S)-X-PX-K, which is highly conserved within the shikimate dehydrogenase family. The recombinant shikimate dehydrogenase spectrum determined by CD spectroscopy showed that the percentages for $\alpha$-helix, $\beta$-sheet, $\beta$-turn, and random coil were 29.2%, 9.3%, 32.7%, and 28.8%, respectively. The enzymatic characterization demonstrates that it appears to be fully active at pH from 9.0 to 12, and temperature $63^{\circ}C$. The apparent Michaelis constant for shikimic acid and $NADP^+$ were calculated to be about $29.5\;{\mu}M$ and $63\;{\mu}M$. The recombinant shikimate dehydrogenase catalyzes the substrate in the presence of $NADP^+$ with an enzyme turnover number of $399\;s^{-1}$. Zymological studies suggest that the cloned shikimate dehydrogenase from M. tuberculosis has a pretty activity, and the work should help in the discovery of enzyme inhibitors and further of possible antimicrobial agents against Mycobacterium tuberculosis.

Improving Scanner Data Collection in P4-based SDN

Yun-Zhan Cai,Chih-Hao Lai,Yu-Ting Wang,Meng-Hsun Tsai 한국통신학회 2020 한국통신학회 APNOMS Vol.2020 No.09

Port scanning is a well-known behavior when a botnet searches target devices. To detect port scanning accurately, data with high discriminatory power are indispensable. Most related works, however, focus on data analysis methods but neglect storage limitations of switches, which makes their methods impractical. Therefore, we propose a new data collection method for collecting network information of port scanning in P4-based SDN named 0-replacement. Through simulations, we compare the 0-replacement method with two classic data collection methods. Results show that the 0-replacement method improves the true positive ratio by at least 25 percentage points but only consumes 0.36% memory space.

Thermal Stability, Adhesion and Electrical Studies on (Ti,Zr)Nx Thin Films as Low Resistive Diffusion Barriers between Cu and Si

Cheng-Lin Huang,Chih-Huang Lai,Po-Hao Tsai,Yu-Lin Kuo,Jing-Cheng Lin,Chiapyng Lee 대한금속·재료학회 2014 ELECTRONIC MATERIALS LETTERS Vol.10 No.3

In this study, we investigated the thermal stability, wettability, adhesion and reliability of (Ti,Zr)Nx films used as the diffusion barrier between Cu and Si. (Ti,Zr)Nx films were prepared by DC reactive magnetron sputtering from a Ti-5 at. % Zr alloy target in N2/Ar gas mixtures. A minimum film resistivity of 59.3 μΩ cm was obtained at an N2/Ar flow ratio of 2.75, which corresponds to the near stoichiometric composition (N/(Ti,Zr) ratio ~0.95). The sheet resistance of Cu/(Ti,Zr)N0.95/Si was not significantly increased until annealing above 750°C, indicating good thermal stability. On the other hand, the adhesion energy between Cu and the (Ti,Zr)Nx film was reduced as the N/Ti ratio was increased. To obtain reliable performance on stress-induced-voiding (SIV) and electromigration (EM) tests, we proposed to use (Ti,Zr)/(Ti,Zr)Nx/(Ti,Zr) tri-layers. We suggest that the interfacial adhesion between barrier and Cu plays an important role in reliability. The proposed tri-layer structure may be a promising candidate for a barrier, as it exhibits excellent reliability without increasing resistance.

IBM Zigbee Positioning Method for Smart Home Applications

Ming-Hui Jin,Chung-Jung Fu,Chih-Hao Yu,Hung-Ren Lai,Ming-Whei Feng 보안공학연구지원센터 2008 International Journal of Smart Home Vol.2 No.2

This paper presents a smart home system prototype which employs an indoor positioning system called the III Beacon Match (I3BM) positioning method to intelligently trigger the appropriately services for the home members. To overcome the ninja problem in the I3BM method, the signal filtering, adjustment and smooth procedures are proposed. The proposed system prototype employs the Zigbee module to implement the prototypes of the components for the I3BM positioning method, and the prototypes had passed the ZigBee Compliant Platform (ZCP) certification test. The proposed system prototype which intelligently controls the air condition and light system for smart home applications is also verifying in our demo room and in the smart house in National Taiwan University.

Apple RING finger E3 ubiquitin ligase MdMIEL1 negatively regulates salt and oxidative stresses tolerance

Jian-Ping An,Xin Liu,Lai-Qing Song,Chun-Xiang You,Xiao-Fei Wang,Yu-Jin Hao 한국식물학회 2017 Journal of Plant Biology Vol.60 No.2

RING-finger-containing E3 ubiquitin ligases play important roles in plant response to biotic and abiotoc stresses. In this study, through homology analysis, a Malus× domestica MYB30-Interacting E3 Ligase 1 gene, MdMIEL1, was identified and subsequently cloned from apple ‘Gala’ (Malus×domestica). MdMIEL1 contained a zinc finger domain close to N-terminus and a RING finger domain close to Cterminus. Expression of MdMIEL1 was significantly induced by NaCl and H2O2 treatments. Further study demonstrated that the MdMIEL1-overexpressing Arabidopsis and apple calli were less tolerance to salt stress than wild-type control. In addition, transgenic plants had higher levels of reactive oxygen species (ROS) (H2O2 and O2 –). And transgenic Arabidopsis and apple calli exhibited more sensitive phenotype to H2O2 treatment, which was associated with increased levels of ROS. These findings indicate MdMIEL1 is an important regulator involved in plant response to salt and oxidative stresses tolerance.

Analysis, Design, and Implementation of a High-Performance Rectifier

Wang, Chien-Ming,Tao, Chin-Wang,Lai, Yu-Hao The Korean Institute of Power Electronics 2016 JOURNAL OF POWER ELECTRONICS Vol.16 No.3

A high-performance rectifier is introduced in this study. The proposed rectifier combines the conventional pulse width modulation, soft commutation, and instantaneously average line current control techniques to promote circuit performance. The voltage stresses of the main switches in the rectifier are lower than those in conventional rectifier topologies. Moreover, conduction losses of switches in the rectifier are certainly lower than those in conventional rectifier topologies because the power current flow path when the main switches are turned on includes two main power semiconductors and the power current flow path when the main switches are turned off includes one main power semiconductor. The rectifier also adopts a ZCS-PWM auxiliary circuit to derive the ZCS function for power semiconductors. Thus, the problem of switching losses and EMI can be improved. In the control strategy, the controller uses the average current control mode to achieve fixed-frequency current control with stability and low distortion. A prototype has been implemented in the laboratory to verify circuit theory.

A Study of Optical Properties of InGaAs/GaAs Quantum Dots

Gwo-Jen Jan,Chih-Ming Lai,Fu-Yu Chang,Hao-Hsing Lin 한국물리학회 2003 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.42 No.III

The optical properties of InGaAs/GaAs quantum dots (QDs) were investigated by temperature-dependent photoluminescence (PL) and photoreflectance (PR) spectroscopies. The surface morphology and structure analysis of InGaAs QDs were also examined and characterized by a field emission scanning electron microscope (SEM) and an atomic force microscope (AFM). The In$_{0.5}$Ga$_{0.5}$As/GaAs self-assembled QDs specimens were grown with gas-source molecular beam epitaxy and migration enhanced techniques. The area density of the QDs is on an order of magnitude about 1 $\times$ 10$^{10}$ dots/cm$^2$. The measured PL results exhibited 5 major energy peaks, two of which are attributed to InGaAs QDs, one is attributed to the InGaAs wetting layer and the other two are attributed to GaAs band-gap transitions. Two of the low energy features are identified to the optical transitions of the ground state. They were originated from the two kinds of InGaAs QDs which might be formed with slight change of the indium composition. An inverted ``S curve'' shape of the temperature-dependent PL peak energies was observed. This abnormal behavior of the line-shape is attributed to carrier localization. The results of PR measurement which reveal energy features on the high energy side contributed by GaAs is also reported.