Application and optimal design of the bionic guide vane to improve the safety serve performances of the reactor coolant pump

Liu Haoran,Wang Xiaofang,Lu Yeming,Yan Yongqi,Zhao Wei,Wu Xiaocui,Zhang Zhigang 한국원자력학회 2022 Nuclear Engineering and Technology Vol.54 No.7

As an important device in the nuclear island, the nuclear coolant pump can continuously provide power for medium circulation. The vane is one of the stationary parts in the nuclear coolant pump, which is installed between the impeller and the casing. The shape of the vane plays a significant role in the pump's overall performance and stability which are the important indicators during the safety serve process. Hence, the bionic concept is firstly applied into the design process of the vane to improve the performance of the nuclear coolant pump. Taking the scaled high-performance hydraulic model (on a scale of 1:2.5) of the coolant pump as the reference, a united bionic design approach is proposed for the unique structure of the guide vane of the nuclear coolant pump. Then, a new optimization design platform is established to output the optimal bionic vane. Finally, the comparative results and the corresponding mechanism are analyzed. The conclusions can be gotten as: (1) four parameters are introduced to configure the shape of the bionic blade, the significance of each parameter is herein demonstrated; (2) the optimal bionic vane is successfully obtained by the optimization design platform, the efficiency performance and the head performance of which can be improved by 1.6% and 1.27% respectively; (3) when compared to the original vane, the optimized bionic vane can improve the inner flow characteristics, namely, it can reduce the flow loss and decrease the pressure pulsation amplitude; (4) through the mechanism analysis, it can be found out that the bionic structure can induce the spanwise velocity and the vortices, which can reduce drag and suppress the boundary layer separation.

Application of amine-loaded activated carbon fiber in CO2 capture and separation

Haoran Liu,Xinmei Lu,Liying Liu,Jian Wang,Pengyu Wang,Peng Gao,Tingsheng Ren,Guo Tian,Di Wang 한국화학공학회 2022 Korean Journal of Chemical Engineering Vol.39 No.9

The CO2 emitted by coal-fired power plants is the main factor leading to global warming, and the captureof CO2 in the flue gas of power plants is still the main task at this stage. Many adsorbents have been developed to captureCO2 in high-temperature flue gas, but some materials are complicated to synthesize or the cost is too high. Here,we used low-cost raw materials activated carbon fiber and PEI, and used green synthesis to synthesize new adsorbentsin order to capture CO2 in high-temperature flue gas of a power plant. To improve the performance of highly porousactivated carbon fiber (ACF) in CO2 capture and separation, an organic polymer polyethylenimine (PEI) was loadedsuccessfully into the oxidized ACF. The modified adsorbent was tested by FT-IR, XRD and SEM, and the CO2 adsorptioncapacity and CO2/N2 selectivity were analyzed. The results showed that the as-synthesized PEI-modified adsorbenthas a CO2 adsorption capacity of 2.5mmol/g, which is 1.7 times better than that of the pristine ACF adsorbent(1.5mmol/g), at 1 bar and 333 K, and it has excellent CO2/N2 selectivity, as calculated by ideal adsorption solution theory(IAST). These data indicate that PEI was loaded successfully into the oxidized ACF. In addition, the dual site Langmuirisotherm equation and Langmuir isotherm equation can be in good agreement with the adsorption curves ofCO2 and N2. In comparison with other composite adsorbents, the preparation process of the present new adsorbent ishighly environmentally friendly, the synthesis method is simple and the cost is low, which demonstrates potential applicationsin the separation of CO2 from the flue gas of power plants.

Gliotoxin is Antibacterial to Drug-resistant Piscine Pathogens

Haoran Feng,Sen Liu,SUMINGZHI,김은라,홍종기,정지형 한국생약학회 2018 Natural Product Sciences Vol.24 No.4

By activity-guided fractionation, gliotoxin was isolated as an antibacterial metabolite of the fungus Penicillium decumbens which was derived from the jellyfish Nemopilema nomurai. Gliotoxin was further evaluated for antibacterial activity against several piscine and human MDR (multidrug resistance) pathogens. Gliotoxin showed significant antibacterial activity against Gram-positive piscine pathogens such as Streptococcus iniae FP5228, Streptococcus iniae FP3187, Streptococcus parauberis FP3287, Streptococcus parauberis SPOF3K, S. parauberis KSP28, and Lactococcus garvieae FP5245. Gliotoxin showed strong activity especially against S. parauberis SPOF3K and S. iniae FP5228, which are resistant to oxytetracycline. It is noteworthy that gliotoxin effectively suppressed streptococci which are the major pathogens for piscine infection and mortality in aquaculture industry. Gliotoxin also showed strong antibacterial activity against multidrug- resistant human pathogens (MDR) including Enterococcus faecium 5270 and MRSA (methicillin-resistant Staphylococcus aureus) 3089.

A bibliometric review on latent topics and trends of the empirical MOOC literature (2008–2019)

Liu, Caixia,Zou, Di,Chen, Xieling,Xie, Haoran,Chan, Wai Hong 서울대학교 교육연구소 2021 Asia Pacific Education Review Vol.22 No.3

Massive Open Online Courses (MOOCs) have become a popular learning mode in recent years, especially since the outbreak of COVID-19 in late 2019, which had resulted in a signifcant increase in associated research. This paper presents a bibliometric review of 1078 peer-reviewed MOOC studies between 2008 and 2019. These papers are extracted from three infuential databases, the Web of Science (WOS), Scopus, and the Education Resources Information Center (ERIC). The MOOC literature analysis with a bibliometric approach identifed the research trends, journals, countries/regions, and institutions with high H-index, scientifc collaborations, research topics, topic distributions of the prolifc countries/regions and institutions, and annual topic distributions, after which the representative research and research implications were discussed. This review gives researchers a deep and comprehensive understanding of current MOOC research and identifes potential research topics and collaborative partners, which supports MOOC-related future research.

IL-33 Promotes ST2-Dependent Fibroblast Maturation via P38 and TGF-β in a Mouse Model of Epidural Fibrosis

Wang Haoran,Wu Tao,Hua Feng,Sun Jinpeng,Bai Yunfeng,Wang Weishun,Liu Jun,Zhang Mingshun 한국조직공학과 재생의학회 2022 조직공학과 재생의학 Vol.19 No.3

BACKGROUND: Recent evidence suggests that IL-33, a novel member of the IL-1b family, is involved in organ fibrosis. However, the roles of IL-33 and its receptor ST2 in epidural fibrosis post spine operation remain elusive. METHODS: A mouse model of epidural fibrosis was established after laminectomy. IL-33 in the wound tissues post laminectomy was measured with Western blotting, ELISA and immunoflurosence imaging. The fibroblast cell line NIH- 3T3 and primary fibroblasts were treated with IL-33 and the mechanisms of maturation of fibroblasts into myofibroblasts were analyzed. To explore roles of IL-33 and its receptor ST2 in vivo, IL-33 knockout (KO) and ST2 KO mice were employed to construct the model of laminectomy. The epidural fibrosis was evaluated using H&E and Masson staining, western-blotting, ELISA and immunohistochemistry. RESULTS: As demonstrated in western blotting and ELISA, IL-33 was increased in epidural wound tissues post laminectomy. The immunoflurosence imaging revealed that endothelial cells (CD31?) and fibroblasts (a-SAM?) were major producers of IL-33 in the epidural wound tissues. In vitro, IL-33 promoted fibroblast maturation, which was blocked by ST2 neutralization antibody, suggesting that IL-33-promoted-fibroblasts maturation was ST2 dependent. Further, IL-33/ ST2 activated MAPK p38 and TGF-b pathways. Either p38 inhibitor or TGF-b inhibitor decreased fibronectin and a-SAM production from IL-33-treated fibroblasts, suggesting that p38 and TGF-b were involved with IL-33/ST2 signal pathways in the fibroblasts maturation. In vivo, IL-33 KO or ST2 KO decreased fibronectin, a-SMA and collagen deposition in the wound tissues of mice that underwent spine surgery. In addition, TGF-b1 was decreased in IL-33 KO or ST2 KO epidural wound tissues. CONCLUSION: In summary, IL-33/ST2 promoted fibroblast differentiation into myofibroblasts via MAPK p38 and TGFb in a mouse model of epidural fibrosis after laminectomy.

Large eddy simulation on the turbulent mixing phenomena in 3×3 bare tight lattice rod bundle using spectral element method

Ju, Haoran,Wang, Mingjun,Wang, Yingjie,Zhao, Minfu,Tian, Wenxi,Liu, Tiancai,Su, G.H.,Qiu, Suizheng Korean Nuclear Society 2020 Nuclear Engineering and Technology Vol.52 No.9

Subchannel code is one of the effective simulation tools for thermal-hydraulic analysis in nuclear reactor core. In order to reduce the computational cost and improve the calculation efficiency, empirical correlation of turbulent mixing coefficient is employed to calculate the lateral mixing velocity between adjacent subchannels. However, correlations utilized currently are often fitted from data achieved in central channel of fuel assembly, which would simply neglect the wall effects. In this paper, the CFD approach based on spectral element method is employed to predict turbulent mixing phenomena through gaps in 3 × 3 bare tight lattice rod bundle and investigate the flow pulsation through gaps in different positions. Re = 5000,10000,20500 and P/D = 1.03 and 1.06 have been covered in the simulation cases. With a well verified mesh, lateral velocities at gap center between corner channel and wall channel (W-Co), wall channel and wall channel (W-W), wall channel and center channel (W-C) as well as center channel and center channel (C-C) are collected and compared with each other. The obvious turbulent mixing distributions are presented in the different channels of rod bundle. The peak frequency values at W-Co channel could have about 40%-50% reduction comparing with the C-C channel value and the turbulent mixing coefficient β could decrease around 25%. corrections for β should be performed in subchannel code at wall channel and corner channel for a reasonable prediction result. A preliminary analysis on fluctuation at channel gap has also performed. Eddy cascade should be considered carefully in detailed analysis for fluctuating in rod bundle.

Oxygen tank for synergistic hypoxia relief to enhance mitochondria-targeted photodynamic therapy

Xianghui Li,Haoran Wang,Zhiyan Li,Dandan Li,Xiaofeng Lu,Shichao Ai,Yuxiang Dong,Song Liu,Jinhui Wu,Wenxian Guan 한국생체재료학회 2022 생체재료학회지 Vol.26 No.4

Background: Mitochondria play an essential role in cellular redox homeostasis maintenance and meanwhile serve as an important target for organelle targeted therapy. Photodynamic therapy (PDT) is a promising strategy for organelle targeted therapy with noninvasive nature and highly spatiotemporal selectivity. However, the efficacy of PDT is not fully achieved due to tumor hypoxia. Moreover, aerobic respiration constantly consumes oxygen and leads to a lower oxygen concentration in mitochondria, which continuously limited the therapeutic effects of PDT. The lack of organelle specific oxygen delivery method remains a main challenge. Methods: Herein, an Oxygen Tank is developed to achieve the organelle targeted synergistic hypoxia reversal strategy, which not only act as an oxygen storage tank to open sources and reduce expenditure, but also coated with red blood cell membrane like the tank with stealth coating. Within the oxygen tank, a mitochondrion targeted photosensitizer (IR780) and a mitochondria respiration inhibitor (atovaquone, ATO) are co-loaded in the RBC membrane (RBCm) coated perfluorocarbon (PFC) liposome core. Results: Inside these bio-mimic nanoparticles, ATO effectively inhibits mitochondrial respiration and economized endogenous oxygen consumption, while PFC supplied high-capacity exogenous oxygen. These Oxygen modulators reverse the hypoxia status in vitro and in vivo, and exhibited a superior anti-tumor activity by mitochondria targeted PDT via IR780. Ultimately, the anti-tumor effects towards gastric cancer and colon cancer are elicited in vivo. Conclusions: This oxygen tank both increases exogeneous oxygen supply and decreases endogenous oxygen consumption, may offer a novel solution for organelle targeted therapies.

A Novel Strategy for Thermostability Improvement of Trypsin Based on N-Glycosylation within the Ω-Loop Region

Guo, Chao,Liu, Ye,Yu, Haoran,Du, Kun,Gan, Yiru,Huang, He The Korean Society for Microbiology and Biotechnol 2016 Journal of microbiology and biotechnology Vol.26 No.7

The Ω-loop is a nonregular and flexible structure that plays an important role in molecular recognition, protein folding, and thermostability. In the present study, molecular dynamics simulation was carried out to assess the molecular stability and flexibility profile of the porcine trypsin structures. Two Ω-Loops (fragment 57-67 and fragment 78-91) were confirmed to represent the flexible region. Subsequently, glycosylation site-directed mutations (A73S, N84S, and R104S) were introduced within the Ω-loop region and its wing chain based on its potential N-glycosylation sites (Asn-Xaa-Ser/Thr consensus sequences) and structure information to improve the thermostability of trypsin. The result demonstrated that the half-life of the N84S mutant at 50℃ increased by 177.89 min when compared with that of the wild-type enzyme. Furthermore, the significant increase in the thermal stability of the N84S mutant has also been proven by an increase in the T_m values determined by circular dichroism. Additionally, the optimum temperatures of the wild-type enzyme and the N84S mutant were 75℃ and 80℃, respectively. In conclusion, we obtained the thermostability-improved enzyme N84S mutant, and the strategy used to design this mutant based on its structural information and N-linked glycosylation modification could be applied to engineer other enzymes to meet the needs of the biotechnological industry.

Ethanol Induces Autophagy Regulated by Mitochondrial ROS in Saccharomyces cerevisiae

( Hongjuan Jing ),( Huanhuan Liu ),( Lu Zhang ),( Jie Gao ),( Haoran Song ),( Xiaorong Tan ) 한국미생물 · 생명공학회 2018 Journal of microbiology and biotechnology Vol.28 No.12

Ethanol accumulation inhibited the growth of Saccharomyces cerevisiae during wine fermentation. Autophagy and the release of reactive oxygen species (ROS) were also induced under ethanol stress. However, the relation between autophagy and ethanol stress was still unclear. In this study, expression of the autophagy genes ATG1 and ATG8 and the production of ROS under ethanol treatment in yeast were measured. The results showed that ethanol stress very significantly induced expression of the ATG1 and ATG8 genes and the production of hydrogen peroxide (H₂O₂) and superoxide anion (O₂ ^·-). Moreover, the atg1 and atg8 mutants aggregated more H₂O₂ and O₂ ^·- than the wild-type yeast. In addition, inhibitors of the ROS scavenging enzyme induced expression of the ATG1 and ATG8 genes by increasing the levels of H₂O₂ and O₂ ^·-. In contrast, glutathione (GSH) and N-acetylcystine (NAC) decreased ATG1 and ATG8 expression by reducing H₂O₂ and O₂ ^·- production. Rapamycin and 3-methyladenine also caused an obvious change in autophagy levels and simultaneously altered the release of H₂O₂ and O₂ ^·-. Finally, inhibitors of the mitochondrial electron transport chain (mtETC) increased the production of H₂O₂ and O₂ ^·- and also promoted expression levels of the ATG1 and ATG8 genes. In conclusion, ethanol stress induced autophagy which was regulated by H₂O₂ and O₂ ^·- derived from mtETC, and in turn, the autophagy contributed to the elimination H₂O₂ and O₂ ^·-.

A Novel Strategy for Thermostability Improvement of Trypsin Based on N-Glycosylation within the Ω-Loop Region

( Chao Guo ),( Ye Liu ),( Haoran Yu ),( Kun Du ),( Yiru Gan ),( He Huang ) 한국미생물 · 생명공학회 2016 Journal of microbiology and biotechnology Vol.26 No.6

The Ω-loop is a nonregular and flexible structure that plays an important role in molecular recognition, protein folding, and thermostability. In the present study, molecular dynamics simulation was carried out to assess the molecular stability and flexibility profile of the porcine trypsin structures. Two Ω-Loops (fragment 57-67 and fragment 78-91) were confirmed to represent the flexible region. Subsequently, glycosylation site-directed mutations (A73S, N84S, and R104S) were introduced within the Ω-loop region and its wing chain based on its potential N-glycosylation sites (Asn-Xaa-Ser/Thr consensus sequences) and structure information to improve the thermostability of trypsin. The result demonstrated that the half-life of the N84S mutant at 50°C increased by 177.89 min when compared with that of the wild-type enzyme. Furthermore, the significant increase in the thermal stability of the N84S mutant has also been proven by an increase in the Tm values determined by circular dichroism. Additionally, the optimum temperatures of the wild-type enzyme and the N84S mutant were 75°C and 80°C, respectively. In conclusion, we obtained the thermostability-improved enzyme N84S mutant, and the strategy used to design this mutant based on its structural information and N-linked glycosylation modification could be applied to engineer other enzymes to meet the needs of the biotechnological industry.