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( Zhenyue Feng ),( Defu Liu ),( Ziwen Liu ),( Yimin Liang ),( Yanhong Wang ),( Qingpeng Liu ),( Zhenhua Liu ),( Zhongjing Zang ),( Yudong Cui ) 한국미생물 · 생명공학회 2020 Journal of microbiology and biotechnology Vol.30 No.7
A putative multidrug efflux gene, yddA, was cloned from the Escherichia coli K-12 strain. A drugsensitive strain of E. coli missing the main multidrug efflux pump AcrB was constructed as a host and the yddA gene was knocked out in wild-type (WT) and drug-sensitive E. coliΔacrB to study the yddA function. Sensitivity to different substrates of WT E.coli, E. coliΔyddA, E. coliΔacrB and E. coliΔacrBΔyddA strains was compared with minimal inhibitory concentration (MIC) assays and fluorescence tests. MIC assay and fluorescence test results showed that YddA protein was a multidrug efflux pump that exported multiple substrates. Three inhibitors, ortho-vanadate, carbonyl cyanide m-chlorophenylhydrazone (CCCP), and reserpine, were used in fluorescence tests. Ortho-vanadate and reserpine significantly inhibited the efflux and increased accumulation of ethidium bromide and norfloxacin, while CCCP had no significant effect on YddA-regulated efflux. The results indicated that YddA relies on energy released from ATP hydrolysis to transfer the substrates and YddA is an ABC-type multidrug exporter. Functional study of unknown ATP-binding cassette (ABC) superfamily transporters in the model organism E. coli is conducive to discovering new multidrug resistance-reversal targets and providing references for studying other ABC proteins of unknown function.
Feng Zhou,Jinjin Cai,Xiaoning Mao,Zhenyu Wu,Yong Nie 한국화학공학회 2022 Korean Journal of Chemical Engineering Vol.39 No.9
As a green plasticizer, the industrial production of dioctyl terephthalate (DOTP) is still facing the problemof high energy consumption. To optimize the production process and reactor, it is essential to understand the kineticbehavior of reaction system. In this work, the two-step consecutive esterification of solid terephthalic acid (PTA) and 2-ethylhexanol (2-EH) catalyzed by tetrabutyl titanate was studied. First, the equilibrium constants and enthalpies of thetwo-step reaction were experimentally determined and validated by the group contribution methods. Then, a pseudohomogeneouskinetic model was developed, and the reaction order of PTA was corrected to reflect its solid phase characteristic. Non-isothermal kinetic experiments were carried out under different initial feed molar ratios and catalystconcentrations, and the kinetic parameters in the model were estimated by mathematical regression. The model predicteddata agreed well with the experimental data. Finally, the analyses of reaction rate showed that the first-step reactionwas the rate-controlling step of the whole esterification process.
( Guijian Feng ),( Zhenyu Zhang ),( Chunyan Diao ),( Jun Jiang ),( Shuying Zheng ),( Yulan Liu ) 대한소화기기능성질환·운동학회 2015 Journal of Neurogastroenterology and Motility (JNM Vol.21 No.2
Background/Aims To establish an animal model of laryngopharyngeal reflux (LPR) and study the effect of LPR on the laryngopharyngeal mucosal ultrastructure. Methods Ten Bama minipigs were randomly divided into control group and stent group. Every pig underwent endoscope, and baseline pH was monitored for 4 hours at laryngopharynx and distal esophagus, then specimens from laryngopharyngeal mucosa were biopsied. For the control group, these procedures were repeated on the 14th day. In the stent group, a custom-designed esophageal stent suit was implanted into esophagus, laryngopharyngeal and distal esophageal pH monitoring lasted for 2 hours, then stent suit was removed 3 days later. At last, the same procedures were done as the control group on the 14th day. Specimens were observed under transmission electron microscope to measure the intercellular space and desmosome number. Results In the control group, there was no laryngopharyngeal reflux on the first day and 14th day. Before the stent was implanted, there was also no laryngopharyngeal reflux in the stent group. In both 2 hours and 14 days after stent implantation, the num - ber of reflux, reflux time, and percentage time of pH < 4.0 were significantly increased (P < 0.05) in the stent group. There was no difference in intercellular space and desmosomes in the control group between baseline and 14th day. In the stent group, intercellular space of laryngopharyngeal mucosa was significantly increased (0.37 μm vs 0.96 μm, P = 0.008), and the number of desmosomes was significantly decreased (20.25 vs 9.5, P = 0.003). Conclusions A Bama minipig model of LPR was established by implanting a custom-designed stent suit. LPR might destroy the laryngophar yngeal mucosal barrier. (J Neurogastroenterol Motil 2015;21:182-188)
Wenyou Zhu,Yu Tie,Zhenyu Zhu,Yuxia Yang,Shao Feng,Jun Liu 한국식품과학회 2022 Food Science and Biotechnology Vol.31 No.10
Liquid-state fermentation has been increasingly applied in the industrial glutinous rice wine (GRW) production. However, products brewed by this emerging technique possess some deficiencies in flavor quality. Therefore, this study firstly developed and optimized an innovative pulping technique by the synchronously pulping and gelatinizing treatment (Process I) to improve GRW flavor quality, and then revealed the influences of Process I on raw materials properties, oenological parameters, fermentation process, and flavor characteristics of GRW. Results show that Process I significantly (p < 0.05) enriched the soluble solid and crude protein content of glutinous rice milk by improving gelatinization degree and pulping efficiency, which consequently enhanced the microbial growth, glycolysis, and protein decomposition during the GRW fermentation process. GC–MS analysis shows that Process I sequentially significantly (p < 0.05) enhanced the esterification and Ehrlich or Harrison pathway during the fermentation process. This contributed to a higher content of key ester and alcohol compounds.
Li Weijian,Chen Gaohuang,Feng Zhenyu,Zhu Baoyi,Zhou Lilin,Zhang Yuying,Mai Junyan,Jiang Chonghe,Zeng Jianwen 한국유전학회 2021 Genes & Genomics Vol.43 No.12
Background Prostate cancer (PCa) is one of the most common malignancies in men. YTHDF1 may play an important role in promoting PCa progression, but there is no reports to date on YTHDF1 function in PCa. Objective This study explored whether YTHDF1 could regulate TRIM44 in PCa cells. Methods By querying the TCGA database, we evaluated YTHDF1 expression in PCa, the OS and DFS of YTHDF1, and the correlation between YTHDF1 and TRIM44 in PCa. We constructed vectors to interfere with YTHDF1 expression and overexpress TRIM44 to examine the role of YTHDF1 and TRIM44 in PCa cells. Diferentially expressed mRNAs were identifed by mRNA sequencing. The levels of YTHDF1, TRIM44, LGR4, SGTA, DDX20, and FZD8 were measured by qRT-PCR and WB was used to determine YTHDF1 and TRIM44 expression. A CCK-8 assay was used to assess cell proliferation. A Transwell chamber assay was used measure cell migration and invasion ability. Results YTHDF1 was highly expressed in both Pca tissues and cells. PCa patient prognosis with high YTHDF1 expression was relatively poor. Cell function experiments showed that inhibiting YTHDF1 expression decreased cell proliferation, migration, and invasion. RNA sequencing analysis revealed that YTHDF1 may promote PCa cell proliferation, migration, and invasion by modulating TRIM44 expression. Cell function experiments further verifed that YTHDF1 promoted PCa cell proliferation, migration, and invasion by regulating TRIM44. Conclusions YTHDF1 enhances PCa cell proliferation, migration, and invasion by regulating TRIM44.
Running-in performance of 7075 aluminum alloy strengthened by burnishing technology
Cong Ding,Shiqing Feng,Zhizhao Qiao,Zhenyu Zhou,Zhongyu Piao 대한기계학회 2023 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.37 No.5
A 2D ultrasonic burnishing technology was employed to strengthen 7075 aluminum alloy. The running-in experiments for original and burnished samples were implemented, and the running-in performance was explored qualitatively and quantitatively. The results show that the worn surface of an original sample exhibited the peelings, scratches, and abrasive particles, yet the wear form of a burnished sample was relatively single, mainly with scratches. The quantitative parameter “maximum distance between phase points d max ” was calculated. During the friction and wear process, the d max of friction coefficient signal displayed the variation of first decreasing and then stabilizing, which was consistent with the running-in and steadystate stages of the friction system. Compared with the original sample, the burnished sample had a less d max , which indicated that the phase trajectory had a more convergence, and the friction system had a better stability. This study can guide surface strengthening and running-in performance analysis.
Thermo-Mechanical Coupling Analysis of the Actuating Mechanism in a High Speed Press
Jin Cheng,Zhendong Zhou,Yixiong Feng,Zhenyu Liu,Yangyan Zhang 한국정밀공학회 2018 International Journal of Precision Engineering and Vol.19 No.5
In order to ensure the manufacturing precision of an ultra-precision high speed press, an integrated thermo-mechanical coupling model of its actuating mechanism is proposed, which includes the mechanical models of the slider and crankshaft, the thermal models for calculating the heat generation powers at different bearings as well as the heat transfer and heat dissipation in the actuating mechanism. The validity of the proposed thermo-mechanical coupling model is verified by a thermal equilibrium experiment when the press operates under the full load of 3000kN at 300 rpm. A sensitivity analysis is conducted to investigate the simulation errors resulting from the variation of the ambient temperature, the results of which demonstrate that the average ambient temperature should be applied for improving simulation accuracy. Then the thermal stiffness of the actuating mechanism and the thermo-mechanical coupling characteristics of different parts are analyzed by the proposed model with the average ambient temperature applied. The influences of the thermally induced loads on the thermal stiffness are discussed in detail. It is concluded that the temperature rise of the actuating mechanism in the stamping process of a high speed press should be fully considered in the design phase for ensuring its manufacturing precision.
Design and Implementation of an AHRS Based on Gauss Newton and Complementary Filtering Algorithm
ZhiMin Liu,Zhao Kai Ning,Feng Tian,ZhenYue Pang 보안공학연구지원센터 2016 International Journal of Hybrid Information Techno Vol.9 No.8
This paper presents design and implementation of an attitude and heading reference system (AHRS) based on Gauss Newton and Complementary Filtering algorithm (CF). The algorithm uses data measured from the MEMS sensor which contains a three-axis magnetometer, a three-axis angular rate sensor, and a three-axis accelerometer. The filter represents rotations using quaternions rather than Euler angles, which eliminates the long-standing problem of singularities associated with attitude estimation. A process model for rigid body angular motions and angular rate measurements is defined. The process model converts angular rates into quaternion rates, which are integrated to obtain quaternions. The Gauss-Newton iteration algorithm is utilized to find the optimal quaternion that relates the measured accelerations and earth magnetic field in the body coordinate frame to calculated values in the earth coordinate frame. Then fuse the optimal quaternion with the quaternion updated from gyroscope and calculate the attitude angle based on the complementary filtering algorithm . Extensive testing of the filter have proved feasibility and acceptable performance of this AHRS design.