Efficient production of reuterin from glycerol by Lactobacillus reuteri

Dexin WANG,Baek-rock OH,Sun-Yeon HEO,Jung-Hyun JU,Jeong-Woo SEO,Chul Ho KIM 한국생물공학회 2018 한국생물공학회 학술대회 Vol.2018 No.4

Research of the Exciting Current Detection Method of MCR

Wang Jun,Wei Liangliang,Chen Feng,Nie Dexin,Lu Wenhua 보안공학연구지원센터 2016 International Journal of Multimedia and Ubiquitous Vol.11 No.5

Magnetic valve controllable reactor (MCR) is a kind of dynamic reactive power compensation device. The exciting current of MCR is one of the important indexes of operating condition of MCR. This paper firstly analyzed the principle of MCR, and deduced the relationship between the exciting current and the output current, verified by MATLAB/SIMULINK. And then an effective method to detect the exciting current was proposed by this paper. The method has the advantages of optical fiber isolation, high detection precision, strong anti-interference, etc. Finally, a 220v/1200var MCR was experimented in detail. The results demonstrate the accuracy of the theoretical analysis.

Study on Ultimate Capacity of Steel H-Section Members Under Combined Biaxial Bending and Axial Force

Cheng Xin,Wang Xiaxin,Zhang Chao,Duan Dexin 한국강구조학회 2021 International Journal of Steel Structures Vol.21 No.5

The ultimate resistance of steel H-section members under biaxial bending and compression has been discussed in the present paper. Finite element models taking account of geometrical and material nonlinearities are established and validated by previous laboratory test results. A series of parametric studies are then conducted considering diff erent loading angles and a spectrum of fl ange width-to-thickness ratios, web width-to-thickness ratios and axial force ratios. An improved energy infl ection method (EIM), which is verifi ed by comparing the analytical results with numerical results, is proposed in order to determine the ultimate state of the members under biaxial bending. It is shown that the ultimate state determined by EIM occurs when the sectional stress distribution reaches the envelop line. Finally, a simple interaction formula is proposed to predict the ultimate capacity of the steel H-section columns subjected to biaxial bending and compression. It is verifi ed that the interaction formula can provide a satisfactory prediction, in comparison against the European code which tends to off er a relatively conservative estimate. The proposed method is applicable to fl ange width-to-thickness ratios ranging from 8 to 28, web width-to-thickness ratios changing from 30 to 120, and axial force ratios varying from 0 to 0.4.

Establishment and Evaluation of National Power Index System: Evidence from Evidence‐Based Analysis

Li Shijun,Wang Dexin 인하대학교 국제관계연구소 2022 Pacific Focus Vol.37 No.1

National power is the basis of the current competition and game betweenglobal sovereign states. It is the organic integration and concentratedexpression of the multi-dimensional and complex factors of politics, econ-omy, society, culture, ecology, value system, and history of any country.Due to the complexity of national power and the non-objectivity of theassessment, the concept of national power and assessment must be con-structed using multiple levels of evidence. Therefore, this paper constructsa three-level evidence chain national power index system based on the sys-tematic literature review, public value theory, and expert scoring, andtakes the G20 countries as an example to measure the change and motiveforce of national power of the major countries in the world from 1992 to2017. Research shows that national power is fundamentally dependent onthe creation of multiple public values, and the trend of“weak countriesgetting weaker and strong countries getting stronger”among countries hasstrengthened. The increase of national power in different types of valuepower is not synchronous, but there are key points and outstandingimprovements.

Jejubacter calystegiae gen. nov., sp. nov., moderately halophilic, a new member of the family Enterobacteriaceae, isolated from beach morning glory

Lingmin Jiang,Dexin Wang,이정숙,Dae-Hyuk Kim,Jae Cheol Jeong,Cha Young Kim,Suk Weon Kim,Jiyoung Lee 한국미생물학회 2020 The journal of microbiology Vol.58 No.5

Strain KSNA2T, a Gram-negative, moderately halophilic, facultatively anaerobic, motile, rod-shaped bacterium, was isolated from the surface-sterilized stem tissue of a beach morning glory (Calystegia soldanella) plant in Chuja Island, Jejudo, Republic of Korea. Phylogenetic analysis based on 16S rRNA gene and whole-genome sequences revealed that strain KSNA2T formed a distinct lineage within the family Enterobacteriaceae, with the highest 16S rRNA gene sequence similarity to Izhakiella australiensis KCTC 72143T (96.2%) and Izhakiella capsodis KCTC 72142T (96.0%), exhibited 95.5– 95.9% similarity to other genera in the family Enterobacteriaceae and Erwiniaceae. Conserved signature indels analysis elucidated that strain KSNA2T was delimited into family Enterobacteriaceae. KSNA2T genome comprises a circular chromosome of 5,182,800 bp with 56.1% G + C content. Digital DNA-DNA relatedness levels between strain KSNA2T and 18 closely related species were 19.3 to 21.1%. Average nucleotide identity values were between 72.0 and 76.7%. Growth of strain KSNA2T was observed at 4 to 45°C (optimum, 25°C) and pH 5.0 to 12.0 (optimum, pH 7.0) in the presence of 0 to 11% (w/v) NaCl (optimum, 0–7%). The major cellular fatty acids (> 10%) were C16:0 followed by summed feature 8 (C18:1 ω7c and/or C18:1 ω6c), summed feature 3 (C16:1 ω7c and/or C16:1 ω6c), C17:0 cyclo, and C14:0. The major isoprenoid quinone was ubiquinone-8 (Q-8). With combined phylogenetic, genomic, phenotypic, and chemotaxonomic features, strain KSNA2T represents a novel species of a new genus in the family Enterobacteriaceae, for which the name Jejubacter calystegiae gen. nov., sp. nov. is proposed. The type strain is KSNA2T (= KCTC 72234T = CCTCC AB 2019098T).

Improving the Microbial Production of Amino Acids: From Conventional Approaches to Recent Trends

Guoqing Zhang,Xueni Ren,Xiuhong Liang,Yaqun Wang,Dexin Feng,Yujun Zhang,Mo Xian,Huibin Zou 한국생물공학회 2021 Biotechnology and Bioprocess Engineering Vol.26 No.5

Variable industrial strains have been applied in the fermentation of bulk amino acids. Strain discovery and evolution, process optimization are traditional approaches to improve the yield and efficiency of the bio-production process, hence to compete with chemical or enzymatic process in amino acids production. With the fast development of bioengineering and synthetic biology, the strains can be rationally engineered to achieve better performance and gain the capacity in the fermentation of broader range of amino acids, especially for value-added amino acids. This proposed review aims to summarize traditional and recent strains in the microbial production of amino acids, characterize their metabolic pathways and present potential objectives for rational evolution. In addition, this proposed review prospect the recent opportunities and challenges in the microbial production of value-added amino acids (rare amino acids, non-canonical amino acids, and unnatural amino acids).

Facial Synthesis of Zn-Doped Fe3O4 with Enhanced Electromagnetic Wave Absorption Performance in S and C Bands

Zhenfeng Liu,Honglong Xing,Lei Wang,Dexin Tan,Ying Gan,Xiaoli Ji,Guocai Xu 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2016 NANO Vol.11 No.8

In this study, Zn-doped Fe3O4 nanoparticles were successfully synthesized by a facile solvothermal method in the presence of sodium dodecyl sulfate (SDS). The morphology, magnetic properties and electromagnetic wave absorbing properties of these materials were characterized. Results showed that Zn2+ played a significant role in the formation of Zn-doped Fe3O4. With the protection of SDS, highly dispersed Fe3O4 nanoparticles were obtained. The nanoparticle size decreased after Zn2+ doping, and the dispersity deteriorated with increasing Zn2+ doping concentration. Zndoped Fe3O4 exhibited excellent electromagnetic wave absorbing property, which resulted in magnetic loss and dielectric loss at an appropriate doping concentration. The minimum reflection loss (RL) was approximately -27.2 dB at 16.9 GHz. As the coating layer thickness increased to 4.0 mm, the bandwidth was approximately 5.0 GHz corresponding to RL below -10 dB, which nearly covered the entire S band (2–4 GHz) and C band (4–8 GHz). The peak frequency of RL and the number of peaks matched the quarter-wave thickness criteria. It was believed that the Zndoped Fe3O4 could be a potential electromagnetic wave absorbing material in S and C bands.

Molecular cloning of the Bombus terrestris bumblebee venom protein phospholipase A2 and its anti-leukemia effects on K562 cells

Yuling Qiu,Yali Chen,Haiyang Yu,Qianxiang Zhou,Ran Wang,Meihua Jin,Dexin Kong 한국응용곤충학회 2017 Journal of Asia-Pacific Entomology Vol.20 No.2

Bee venom has been used for treating various diseases for a long time. However, the bioactive constituents of bee venom and its mechanisms remain poorly understood. In the present study, phospholipase A2 (Bt-PLA2) cDNA was cloned, and a mature form of Bt-PLA2 was purified from bumblebee venom (Bombus terrestris). The differentiation induction and apoptosis induction activities of Bt-PLA2 on chronic myelogenous leukemia (CML) K562 cells were also evaluated. Bt-PLA2 cDNA has 540 nucleotides that encode a 180-amino-acid protein. The purified, mature form of Bt-PLA2 was an 18-kDa protein, and it inhibited K562 cell growth, determined by an IC50 value of 29.5 ng/μl. Moreover, Bt-PLA2 induced erythroid differentiation of K562 cells in a dose-dependent manner, and this was supplemented with the upregulation of glycophorin A (GPA) mRNA expression. Bt-PLA2- induced apoptosis, analyzed by DAPI staining, was correlated with the result analyzed by AnnexinV-FITC/PI binding. Furthermore, activation of caspase 3 and poly ADP-ribose polymerase (PARP) and inhibition of p-Akt, determined by western blot, further demonstrated that Bt-PLA2 induced apoptosis mainly through the Akt pathway. The parallel induction of erythroblasts differentiation of K562 cells and apoptosis due to Bt-PLA2 treatment demonstrated the potential use of Bt-PLA2 as an anti-leukemia drug lead.