DRA0336, Another OxyR Homolog, Involved in the Antioxidation Mechanisms in Deinococcus radiodurans

Longfei Yin,Liangyan Wang,Huiming Lu,Guangzhi Xu,Hongdan Zhan,Bing Tian,Yuejin Hua,Huan Chen 한국미생물학회 2010 The journal of microbiology Vol.48 No.4

A novel OxyR (DR0615) with one conserved cysteine that senses hydrogen peroxide in Deinococcus radiodurans had been identified in our previous work. Comparative genomics revealed that D. radiodurans possesses another OxyR homolog, OxyR2 (DRA0336). In this study, we constructed the deletion mutant of oxyR2 and the double mutant of both the OxyR homologs to investigate the role of OxyR in response to oxidative stress in D. radiodurans. Deletion of oxyR2 resulted in an obviously increased sensitivity to hydrogen peroxide, and the double mutant for oxyR and oxyR2 was significantly more sensitive than any of the two single mutants. The total catalase activity of the double mutant was lower than that of any of the single mutants, and reactive oxygen species (ROS) accumulated to a greater extent. DNA microarray analysis further suggested that oxyR2 was involved in antioxidation mechanisms. Site-direct mutagenesis and complementation analysis revealed that C228 in OxyR2 was essential. This is the first report of the presence of two OxyR in one organism. These results suggest that D. radiodurans OxyR and OxyR2 function together to protect the cell against oxidative stress.

Resveratrol suppresses the epithelial-to-mesenchymal transition in PC-3 cells by down-regulating the PI3K/AKT signaling pathway

Zhi Wang,Longxiang Wu,Shiyu Tong,Xiheng Hu,Xiongbing Zu,Yuan Li,Wei He,Longfei Liu,Minfeng Chen,Lin Qi 한국통합생물학회 2016 Animal cells and systems Vol.20 No.2

Resveratrol possesses a wide spectrum of pharmacological properties and has been an ideal alternative drug for the treatment of different cancers, including prostate cancer. However, the mechanisms by which resveratrol inhibits the growth of prostate cancer are still not fully elucidated. To understand the effect of resveratrol on the apoptosis and the epithelial-tomesenchymal transition (EMT) of prostate cancer as well as its related mechanism, we investigated the potential use of resveratrol in PC-3 prostate cancer cells in vitro using real-time PCR, fluorescence-activated cell sorting, Western blotting, etc. Resveratrol suppresses the PC-3 prostate cancer cell growth and induces apoptosis. Resveratrol also influences the expression of EMT-related proteins (increased E-cadherin and decreased Vimentin expression). Finally, resveratrol also suppressed Akt phosphorylation in PC-3 cells. This study indicates that resveratrol may be a potential anti-cancer treatment for prostate cancer; moreover, it provides new evidence that resveratrol suppresses prostate cancer growth and metastasis.

On-line integration of structural identification/damage detection and structural reliability evaluation of stochastic building structures

Ying Lei,Longfei Wang,Lanxin Lu,Dan-dan Xia 국제구조공학회 2017 Structural Engineering and Mechanics, An Int'l Jou Vol.63 No.6

Recently, some integrated structural identification/damage detection and reliability evaluation of structures with uncertainties have been proposed. However, these techniques are applicable for off-line synthesis of structural identification and reliability evaluation. In this paper, based on the recursive formulation of the extended Kalman filter, an on-line integration of structural identification/damage detection and reliability evaluation of stochastic building structures is investigated. Structural limit state is expanded by the Taylor series in terms of uncertain variables to obtain the probability density function (PDF). Both structural component reliability with only one limit state function and system reliability with multi-limit state functions are studied. Then, it is extended to adopt the recent extended Kalman filter with unknown input (EKF-UI) proposed by the authors for on-line integration of structural identification/damage detection and structural reliability evaluation of stochastic building structures subject to unknown excitations. Numerical examples are used to demonstrate the proposed method. The evaluated results of structural component reliability and structural system reliability are compared with those by the Monte Carlo simulation to validate the performances of the proposed method

Capture of CO2 from coal using chemical-looping combustion: Process simulation

Ming Luo,Shuzhong Wang,Jiabin Zhu,Longfei Wang,Mingming Lv 한국화학공학회 2015 Korean Journal of Chemical Engineering Vol.32 No.3

Coal direct chemical-looping combustion (CLC) and coal gasification CLC processes are the two basicapproaches for the application of the CLC technology with coal. Two different combined cycles with the overall thermalinput of 1,000MW (LHV) were proposed and simulated, respectively, with NiO/NiAl2O4 as an oxygen carrierusing the ASPEN software. The oxygen carrier circulation ratio in two CLC processes was calculated, and the influenceof the CLC process parameters on the system performance such as air reactor temperature and the turbine inletsupplementary firing temperature was investigated. Results found were that the circulation ratio of the oxygen carrierin the coal gasification CLC process is smaller than that in the coal direct CLC process. In the coal direct CLCcombined system, the system efficiency is 49.59% with the CO2 capture efficiency of almost 100%, assuming the airreactor temperature at 1,200 oC and the fuel reactor temperature at 900 oC. As a comparison, the system efficiency ofcoal gasification CLC combined system is 40.53% with the CO2 capture efficiency of 85.2% when the turbine inlet temperatureis at 1,350 oC. Increasing the supplementary firing rate or decreasing the air reactor temperature can increasethe system efficiency, but these will reduce the CO2 capture efficiency.

Adoption and Diffusion Rule of LBS in the View of Social Network Privacy– A Case Study of SinaMicroblogLBS

Xia Chen,Tingjie Lu,Longfei Guo,Yu Shen,Chenguang Wang 보안공학연구지원센터 2014 International Journal of Smart Home Vol.8 No.6

Some studies have shown that the attitude and intention of using mobile LBS is strongly influenced by the privacy factor. Since LBS bears prominent privacy attribute, our study selects the aggregation form based on Microblog content in the LBS of SinaMicroblog, namely, LBS Microblog, asthe object of study, acquires an actual Microblog user data sample of over 30,000 items, with over 8.64 million Microblog postings and 20 million Microblog re-postings of these users, conducts a contrastive research on the adoption behavior in LBS of users at Hub nodes and common nodes in social network through relative analysis, and discusses the diffusion rule of LBS through BASS model. The study finds that the structure attribute of users in social network has strong influence on the adoption rule of LBS; the adoption of different types of LBS by users is obviously in consistency; LBS is remarkably influenced by emergencies related to privacy.

On the association analysis of CNV data: a fast and robust family-based association method

Liu, Meiling,Moon, Sanghoon,Wang, Longfei,Kim, Sulgi,Kim, Yeon-Jung,Hwang, Mi Yeong,Kim, Young Jin,Elston, Robert C.,Kim, Bong-Jo,Won, Sungho BioMed Central 2017 BMC bioinformatics Vol.18 No.1

<P><B>Background</B></P><P>Copy number variation (CNV) is known to play an important role in the genetics of complex diseases and several methods have been proposed to detect association of CNV with phenotypes of interest. Statistical methods for CNV association analysis can be categorized into two different strategies. First, the copy number is estimated by maximum likelihood and association of the expected copy number with the phenotype is tested. Second, the observed probe intensity measurements can be directly used to detect association of CNV with the phenotypes of interest.</P><P><B>Results</B></P><P>For each strategy we provide a statistic that can be applied to extended families. The computational efficiency of the proposed methods enables genome-wide association analysis and we show with simulation studies that the proposed methods outperform other existing approaches. In particular, we found that the first strategy is always more efficient than the second strategy no matter whether copy numbers for each individual are well identified or not. With the proposed methods, we performed genome-wide CNV association analyses of hematological trait, hematocrit, on 521 Korean family samples.</P><P><B>Conclusions</B></P><P>We found that statistical analysis with the expected copy number is more powerful than the statistic with the probe intensity measurements regardless of the accuracy of the estimation of copy numbers.</P><P><B>Electronic supplementary material</B></P><P>The online version of this article (doi:10.1186/s12859-017-1622-z) contains supplementary material, which is available to authorized users.</P>

Mechanism of sulfamethoxazole adsorption on wastewater-sludge-based biochar: Sludge type and modification improvement

Yongkui Yang,Yifeng Ling,Longfei Wang,Peizhe Sun,Lin Zhao,Hongyang Wang 한국화학공학회 2023 Korean Journal of Chemical Engineering Vol.40 No.5

With rapid industrialization and population growth, sewage sludge generation has increased worldwide, and it needs to be treated properly. The pyrolysis of sewage sludge into biochar provides sustainable benefits for concomitant pollutant adsorption and waste treatment. Sulfamethoxazole (SMX) antibiotics are highly prevalent in waste-water owing to their widespread utilization and low metabolic rate and removal efficiency during conventional waste-water treatment. Biochar is known to effectively remove pollutants from wastewater. However, the adsorption capacity and mechanism of SMX adsorption onto sludge-based biochar are currently unclear. Therefore, the adsorption behavior of SMX on sludge-based biochar from three sources (raw sludge, compost sludge, and digested sludge) and ZnCl2-modified biochar was investigated. Among the unmodified biochars, raw sludge-based biochar exhibited the highest adsorption capacity, followed by compost sludge-based and digested sludge-based biochar. The pore-forming effect of ZnCl2 application significantly increased the biochar specific surface area, which increased the equilibrium adsorption of SMX from 6.1 mg/g to 49.3 mg/g. The adsorption mechanisms involved electrostatic interactions, pore filling, hydrophobic interactions, hydrogen bonding, and π-π interactions. The findings of this study demonstrate the development of sewage sludge biochar and its effectiveness for the treatment of antibiotics containing wastewater.

Research on High-Frequency Isolation Type of Dual-PWM Variable Frequency Speed Regulation

Liu Jiangong,Liu Wenzhuang,Wang Yiying,Zhang Guilin,Chen Longfei 대한전기학회 2023 Journal of Electrical Engineering & Technology Vol.18 No.4

Frequency converters are widely used in power grids, motor speed regulation, and other fields. When the voltage level is above low voltage and the workspace is limited, traditional frequency converters mostly adopt the power frequency transformer to connect to the power grid. But the structure has the problems of bigger volume and complexity. To solve these problems, this paper proposes a three-stage topology structure of high-frequency isolation type of dual-PWM variable frequency speed regulation based on three-phase rectification, single active isolated DC/DC converter, and three-phase inverter, and analyzes its power transmission characteristics in detail. And a new method that combines high-frequency electrical isolation and frequency conversion is discussed. Then, the control strategies of the new method are also described. Lastly, simulation and experiment are constructed to verify the new design method is correct and feasible, and that the steady and dynamic characteristics of the three-stage high-frequency isolated frequency converter are better.

Simulation-Based Optical Spectra Analyses and Synthesis of Highly Monodispersed Mn-Doped ZnSe Nanocrystal

Mukerem. H Abib,Xudong Yao,Guopeng Li,Longfei Mi,Yajing Chang,Hui Wang,Dabin Yu,YANG JIANG 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2016 NANO Vol.11 No.8

Geometrical structures of (ZnSe)n, n = 3x, (x = 1–4) and (MnxZn2xSe3x), (x = 1–4) clusters were calculated using density functional theory (DFT). Optical/absorption spectra, Raman spectra, HOMO–LUMO gap energy and binding energy of each cluster were calculated. The calculated results show the red shift of the optical/absorption spectra band caused by the manganese atoms doped in ZnSe clusters, and the highest occupied molecular orbital-lowest unoccupied molecular orbital (HOMO–LUMO) gap energy value is decreased. Furthermore, we realized highly monodispersed manganese-doped zinc selenide quantum dots (Mn:ZnSe d-dots) experimentally by using a convenient route. The as-synthesized Mn:ZnSe d-dots were characterized by UV-Vis absorption, photoluminescence (PL), X-ray diffraction (XRD), TEM and HRTEM. The experimental results revealed that the as-prepared Mn:ZnSe d-dots with zincblende structure have an average size of about 3.9 nm.

Seismic behavior of energy dissipation shear wall with CFST column elements

Hao Su,Lihua Zhu,Yaohong Wang,Lei Feng,Zeyu Gao,Yuchen Guo,Longfei Meng,Hanquan Yuan 국제구조공학회 2022 Steel and Composite Structures, An International J Vol.43 No.1

To develop high-efficiency lateral force resistance components for high-rise buildings, a novel energy dissipation shear wall with concrete-filled steel tubular (CFST) column elements was proposed. An energy dissipation shear wall specimen with CFST column elements (GZSW) and an ordinary reinforced concrete shear wall (SW) were constructed, and experimented by low-cycle reversed loading. The mechanical characteristics of these two specimens, including the bearing capacity, ductility, energy dissipation, and stiffness degradation process, were analyzed. The finite-element model of the GZSW was established by ABAQUS. Based on this finite-element model, the effect of the placement of steel-plate energy dissipation connectors on the seismic performance of the shear wall was analyzed, and optimization was performed. The experiment results prove that, the GZSW exhibited a superior seismic performance in terms of bearing capacity, ductility, energy dissipation, and stiffness degradation, in comparison with the SW. The results calculated by the ABAQUS finite-elements model of GZSW corresponded well with the results of experiment, and it proved the rationality of the established finite-elements model. In addition, the optimal placement of the steel-plate energy dissipation connectors was obtained by ABAQUS.