Effects of Quenching Methods and Aging Processes on the Crushing Properties and Microstructure of Al–Zn–Mg Alloy Thin-Walled Square Extrusions

Hui Guo,Jin Zhang,Cheng Wang,Yun‑lai Deng 대한금속·재료학회 2022 METALS AND MATERIALS International Vol.28 No.8

In this study, the effects of different (online quenching and offline quenching) quenching methods and aging processes (T6and T73) on the crashworthiness and microstructural evolution of three Al–Zn–Mg alloys (G1–G3) were studied by conductingtensile test and axial compression tests at room temperature, combined with optical metallography, electron back scattereddiffraction, and transmission electron microscopy microstructural observations. The obtained results revealed that thecrushing properties of three different Al–Zn–Mg alloys subjected to different quenching methods and aging processes weresignificantly different. Their crushing energy absorption of are ranked as follows: G1 > G3 > G2. The highest total energyabsorption gap (between T6 and T73) is the G1 alloy, and the lowest one is the G3 alloy. The largest total energy absorptiongap between the two quenching methods is the G3 alloy, and the smallest one is the G1 alloy. The G2 alloy with the largesttotal amount of Zn + Mg has the highest number density of matrix precipitates, the largest precipitate gap (between T6 andT73) and the smallest precipitate gap between the two quenching methods. The G3 alloy with the largest Zn/Mg ratio hasthe smallest number density of matrix precipitates, the minimum precipitation gap (between T6 and T73) and the maximumprecipitation gap between the two quenching methods. The G1 alloy with the lowest Zn/Mg ratio has the smallest size ofgrain boundary precipitates and PFZ width, while their largest values are obtained for the G3 alloy with the maximum Zn/Mg ratio. As a crushing resistant structural material, the crushing properties is improved without reducing the strength. Theratio of Zn/Mg should be controlled within the range of 4.57–6.15, while the total amount of Zn + Mg should be controlledwithin the range of 6.18–7.01.

Association of Polymorphisms in the Calpain I Gene with Meat Quality Traits in Yanbian Yellow Cattle of China

Xin, Jin,Zhang, Li-Chun,Li, Zhao-Zhi,Liu, Xiao-Hui,Jin, Hai-Guo,Yan, Chang-Guo Asian Australasian Association of Animal Productio 2011 Animal Bioscience Vol.24 No.1

The calpain I (CAPN1) gene is an important marker for meat tenderness and marbling score in the bovine, but there were no studies to determine whether the CAPN1 gene had an association with other meat quality traits. In this study, we examined the relation between genetic polymorphisms of the CAPN1 gene and some meat quality traits in Yanbian Yellow Cattle of China. By PCRSSCP and gene sequencing in 321 unrelated Yanbian yellow cattle, twenty seven single nucleotide polymorphisms (SNPs) were detected in CAPN1, two existed SNPs in exon 8 and exon 17 resulted in the change of AA at F311S and M599V, respectively, and the otherpolymorphisms were at intron 7, 8, 14, 16 and 17. There were different preponderant genotypes at the corresponding gene locus and all genotypes were not associated with tenderness but other meat traits. This is the first study of the relationship between CAPN1 and meat quality besides tenderness in Yanbian yellow cattle of China.

Ginsengenin derivatives synthesized from 20(R)-panaxotriol: Synthesis, characterization, and antitumor activity targeting HIF-1 pathway

Guo, Hong-Yan,Xing, Yue,Sun, Yu-Qiao,Liu, Can,Xu, Qian,Shang, Fan-Fan,Zhang, Run-Hui,Jin, Xue-Jun,Chen, Fener,Lee, Jung Joon,Kang, Dongzhou,Shen, Qing-Kun,Quan, Zhe-Shan The Korean Society of Ginseng 2022 Journal of Ginseng Research Vol.46 No.6

Background: Ginseng possesses antitumor effects, and ginsenosides are considered to be one of its main active chemical components. Ginsenosides can further be hydrolyzed to generate secondary saponins, and 20(R)-panaxotriol is an important sapogenin of ginsenosides. We aimed to synthesize a new ginsengenin derivative from 20(R)-panaxotriol and investigate its antitumor activity in vivo and in vitro. Methods: Here, 20(R)-panaxotriol was selected as a precursor and was modified into its derivatives. The new products were characterized by ¹H-NMR, ¹³C-NMR and HR-MS and evaluated by molecular docking, MTT, luciferase reporter assay, western blotting, immunofluorescent staining, colony formation assay, EdU labeling and immunofluorescence, apoptosis assay, cells migration assay, transwell assay and in vivo antitumor activity assay. Results: The derivative with the best antitumor activity was identified as 6,12-dihydroxy-4,4,8,10,14-pentamethyl-17-(2,6,6-trimethyltetrahydro-2H-pyran-2-yl)hexadecahydro-1H-cyclopenta[a]phenanthren-3-yl(tert-butoxycarbonyl)glycinate (A11). The focus of this research was on the antitumor activity of the derivatives. The efficacy of the derivative A11 (IC₅₀ < 0.3 µM) was more than 100 times higher than that of 20(R)- panaxotriol (IC₅₀ > 30 µM). In addition, A11 inhibited the protein expression and nuclear accumulation of the hypoxia-inducible factor HIF-1α in HeLa cells under hypoxic conditions in a dose-dependent manner. Moreover, A11 dose-dependently inhibited the proliferation, migration, and invasion of HeLa cells, while promoting their apoptosis. Notably, the inhibition by A11 was more significant than that by 20(R)-panaxotriol (p < 0.01) in vivo. Conclusion: To our knowledge, this is the first study to report the production of derivative A11 from 20(R)-panaxotriol and its superior antitumor activity compared to its precursor. Moreover, derivative A11 can be used to further study and develop novel antitumor drugs.

Neutronics modelling of control rod compensation operation in small modular fast reactor using OpenMC

Hui Guo,Xingjie Peng,Yiwei Wu,Xin Jin,Kuaiyuan Feng,Hanyang Gu 한국원자력학회 2022 Nuclear Engineering and Technology Vol.54 No.3

The small modular liquid-metal fast reactor (SMFR) is an important component of advanced nuclearsystems. SMFRs exhibit relatively low breeding capability and constraint space for control rod installation. Consequently, control rods are deeply inserted at beginning and are withdrawn gradually tocompensate for large burnup reactivity loss in a long lifetime. This paper is committed to investigatingthe impact of control rod compensation operation on core neutronics characteristics. This paper presentsa whole core fine depletion model of long lifetime SMFR using OpenMC and the influence of depletionchains is verified. Three control rod position schemes to simulate the compensation process arecompared. The results show that the fine simulation of the control rod compensation process impactssignificantly the fuel burnup distribution and absorber consumption. A control rod equivalent positionscheme proposed in this work is an optimal option in the trade-off between computation time andaccuracy. The control position is crucial for accurate power distribution and void feedback coefficients inSMFRs. The results in this paper also show that the pin level power distribution is important due to theheterogeneous distribution in SMFRs. The fuel burnup distribution at the end of core life impacts theworth of control rods.

Purification and Characterization of a β-Glucosidase from Aspergillus niger and Its Application in the Hydrolysis of Geniposide to Genipin

( Guo Hong Gong ),( Zhi Ming Zheng ),( Hui Liu,Li Wang ),( Jin Shan Diao ),( Peng Wang ),( Gen Hai Zhao ) 한국미생물 · 생명공학회 2014 Journal of microbiology and biotechnology Vol.24 No.6

An extracellular β-glucosidase from Aspergillus niger Au0847 was purified to homogeneity by precipitation with ammonium sulfate, anion exchange, and gel filtration. The purified protein was composed of two subunits with molecular masses of 110 and 120 kDa. Au0847 β-glucosidase exhibited relatively high thermostability and pH stability, and its highest activity was obtained at 65°C and pH 4.6, respectively. As a potential metalloprotein, its enzymatic activity was potently stimulated by manganese ion and DTT. The β-glucosidase displayed avid affinity and high catalytic efficiency for geniposide. Au0847 β-glucosidase has potential value as an industrial enzyme for the hydrolysis of geniposide to genipin.

Influence of nuclear data library on neutronics benchmark of China experimental fast reactor start-up tests

Guo Hui,Jin Xin,Huo Xingkai,Gu Hanyang,Wu Haicheng 한국원자력학회 2022 Nuclear Engineering and Technology Vol.54 No.10

Nuclear data is the basis of reactor physics analysis. This paper aim at studying the influence of major evaluated nuclear data libraries, CENDL-3.2, ENDF/B-VIII.0, JEFF-3.3, and JENDL-4.0u, on the neutronics modelling of CEFR start-up tests. Results show these four libraries have a good performance and consistency in the modelling CEFR start-up tests. The JEFF-3.3 results exhibit only an 8 pcm keff difference with the measurement. The difference in criticality is decomposed by nuclide, which shows the large overestimation of CENDL-3.2 is mainly from the cross-section of 52Cr. Except for few cases, the calculation results are within 1s of measurement uncertainty in control rod worth, sodium void reactivity, temperature reactivity, and subassembly swap reactivity. In the evaluation of axial and radial reaction distribution, there are about 65% of relative errors that are less than 5% and 82% of relative errors that are less than 10%

Visibility detection approach to road scene foggy images

( Fan Guo ),( Hui Peng ),( Jin Tang ),( Beiji Zou ),( Chenggong Tang ) 한국인터넷정보학회 2016 KSII Transactions on Internet and Information Syst Vol.10 No.9

A cause of vehicle accidents is the reduced visibility due to bad weather conditions such as fog. Therefore, an onboard vision system should take visibility detection into account. In this paper, we propose a simple and effective approach for measuring the visibility distance using a single camera placed onboard a moving vehicle. The proposed algorithm is controlled by a few parameters and mainly includes camera parameter estimation, region of interest (ROI) estimation and visibility computation. Thanks to the ROI extraction, the position of the inflection point may be measured in practice. Thus, combined with the estimated camera parameters, the visibility distance of the input foggy image can be computed with a single camera and just the presence of road and sky in the scene. To assess the accuracy of the proposed approach, a reference target based visibility detection method is also introduced. The comparative study and quantitative evaluation show that the proposed method can obtain good visibility detection results with relatively fast speed.

Coherent Population Transfer in a Three-Level System Driven by Unmatched Gaussian Pulses

Hong Guo,Dingan Han,Hong Jin Kong,Hui Sun,Xuzong Chen,Yanfeng Bai 한국물리학회 2004 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.45 No.2

The population transfer in a three-level system driven by unmatched Gaussian pulses is investigated. A set of time-dependent density matrix equations is solved numerically using the rotating wave approximation, and the solution shows that the population of the atomic level depends strongly on the pulse widths of the applied probe and coupling pulses. If the parameters are chosen appropriately, population can be transferred almost completely to the target state, which interacts with the pulse with the smaller pulse width.

Ubiquitination of p53 is Involved in Troglitazone Induced Apoptosis in Cervical Cancer Cells

Chen, Hui-Min,Zhang, Ding-Guo,Wu, Jin-Xiz,Pei, Dong-Sheng,Zheng, Jun-Nian Asian Pacific Journal of Cancer Prevention 2014 Asian Pacific journal of cancer prevention Vol.15 No.5

Peroxisome proliferator-activated receptor gamma (PPAR-${\gamma}$), a ligand-dependent nuclear transcription factor, has been found to widely exist in tumor tissues and plays an important role in affecting tumor cell growth. In this study, we investigated the effect of PPAR-${\gamma}$ on aspects of the cervical cancer malignant phenotype, such as cell proliferation and apoptosis. Cell growth assay, Western blotting, Annexin V and flow cytometry analysis consistently showed that treatment with troglitazone (TGZ, a PPAR-${\gamma}$ agonist) led to dose-dependent inhibition of cervical cancer cell growth through apoptosis, whereas T0070907 (another PPAR-${\gamma}$ antagonist) had no effect on Hela cell proliferation and apoptosis. Furthermore, we also detected the protein expression of p53, p21 and Mdm2 to explain the underlying mechanism of PPAR-${\gamma}$ on cellular apoptosis. Our work, finally, demonstrated the existence of the TGZ-PPAR-${\gamma}$-p53 signaling pathway to be a critical regulator of cell apoptosis. These results suggested that PPAR-${\gamma}$ may be a potential therapeutic target for cervical cancer.

N-Acyl-Homoserine Lactone Quorum Sensing Switch from Acidogenesis to Solventogenesis during the Fermentation Process in Serratia marcescens MG1

( Wensong Jin ),( Hui Lin ),( Huifang Gao ),( Zewang Guo ),( Jiahuan Li ),( Quanming Xu ),( Shujing Sun ),( Kaihui Hu ),( Jung-kul Lee ),( Liaoyuan Zhang ) 한국미생물생명공학회(구 한국산업미생물학회) 2019 Journal of microbiology and biotechnology Vol.29 No.4

N-acyl-homoserine lactone quorum sensing (AHL-QS) has been shown to regulate many physiological behaviors in Serratia marcescens MG1. In the current study, the effects of AHL-QS on the biosynthesis of acid and neutral products by S. marcescens MG1 and its isogenic ΔswrI with or without supplementing exogenous N-hexanoyl-L-homoserine lactone (C₆-HSL) were systematically investigated. The results showed that swrI disruption resulted in rapid pH drops from 7.0 to 4.8, which could be restored to wild type by supplementing C₆-HSL. Furthermore, fermentation product analysis indicated that ΔswrI could lead to obvious accumulation for acidogenesis products such as lactic acid and succinic acid, especially excess acetic acid (2.27 g/l) produced at the early stage of fermentation, whereas solventogenesis products by ΔswrI appeared to noticeably decrease by an approximate 30% for acetoin during 32-48 h and by an approximate 20% for 2,3-butanediol during 24-40 h, when compared to those by wild type. Interestingly, the excess acetic acid produced could be removed in an AHL-QS-independent manner. Subsequently, quantitative real-time PCR was used to determine the mRNA expression levels of genes responsible for acidogenesis and solventogenesis and showed consistent results with those of product synthesis. Finally, by close examination of promoter regions of the analyzed genes, four putative luxI box-like motifs were found upstream of genes encoding acetyl-CoA synthase, lactate dehydrogenase, α-acetolactate decarboxylase, and Lys-like regulator. The information from this study provides a novel insight into the roles played by AHL-QS in switching from acidogenesis to solventogenesis in S. marcescens MG1.