In Vitro Evaluation and Monitoring of the Expression Level and Localization of Aldose Reductase Using Functionalized Quantum Dots and EGFP

Xiaomin Liu,Chengbin Yang,Jing Liu,Jianwei Liu,Rui Hu,Hongwei Lian,Guimiao Lin,Liwei Liu,Ken-Tye Yong,Ling Ye 한국생물공학회 2015 Biotechnology and Bioprocess Engineering Vol.20 No.4

The optimization of aldose reductase (AR) expression levels and tracking of the AR expression sites within the cell is an essential step in developing a platform for the effective production of aldose reductase inhibitors (ARIs). In this study, we have demonstrated the use of both immunocytochemistry and quantum dots-based immunofluorescence techniques for observing and detecting the expression level and localization of AR in the cytoplasm and cell membrane of a eukaryotic cell model with high levels of AR protein expression. Our results show that high expression levels of human AR can be achieved using the eukaryotic cell model that we have developed. The overexpressed AR can be used for translational studies of hAR and the screening of ARIs. More importantly, the use of the established quantum dots-based immunofluorescence technique in the intracellular labeling of AR allows the determination of the expression and distribution of the AR gene. Overall, the use of the interdisciplinary approach of both genetic engineering and quantum dot-based immunofluorescence allows not only the effective production of a desired protein, but also the determination of the cellular localization of such an expressed protein.

Analysis and Optimization of Asymmetric Hybrid Permanent Magnet Motor for Electric Vehicle

Liu Kaiwen,Shi Liwei,Liu Zhengwei,Wang Wenqiang,Ding Hongshan 대한전기학회 2023 Journal of Electrical Engineering & Technology Vol.18 No.5

An asymmetric hybrid permanent magnet motor (AHPMM) is proposed for the traditional permanent magnet motor (TPMM) with a large amount of rare earth materials and high cogging torque. The equivalent magnetic circuit model of the motor is established and the factors affecting the fluctuation of cogging torque are analyzed. With the objective of reducing the torque ripple and cogging torque of the AHPMM, the motor is parametrically modeled and analyzed, and multi-objective hierarchical optimization of the motor parameters is carried out using a hybrid algorithm combining the response surface algorithm and the single scan method, which ultimately determines the optimal combination of motor dimensional parameters. The electromagnetic performance of the AHPMM compared to the TPMM is analyzed using the finite element method. The results show that, without any decrease in output torque, the use of rare-earth materials is reduced by 18.5%, the cogging torque and the total harmonic distortion of the No-load back EMF waveform are reduced by 0.78 Nm and 4.7% respectively compared to the TPMM. Finally, a prototype motor is manufactured and the validity of the theoretical analysis and design of the AHPMM is verified through experiments.

Synthesis of Sulfonated Fluorenyl-Containing Poly(ether ether ketone ketone)s and Their Blends with an Amino-Functionalized Poly(ether ether ketone) for Fuel Cell Applications

Long Li,Baijun Liu,Siyuan Liu,Zhuang Liu,Yunwu Yu,Liwei Jing,Zhenhua Jiang 한국고분자학회 2013 Macromolecular Research Vol.21 No.7

A new family of sulfonated fluorenyl-containing poly(ether ether ketone ketone)s (SFPEEKKs) were successfully synthesized through a mild postsulfonation in concentrated sulfuric acid at room temperature. Further, a series of “molecule-enhanced” blend membranes were prepared based on SFPEEKKs and an amino-functionalized poly(ether ether ketone) by the solution casting method. These blend membranes generally showed higher thermal stability, lower swelling ratio and methanol permeability and superior mechanical properties in comparison with pristine SFPEEKK membranes. The results showed that some blend membranes may be promising proton exchange membranes for fuel cell applications.

The associations of job strain and leisure-time physical activity with the risk of hypertension: the population-based Midlife in the United States cohort study

Xinyue Liu,Timothy A. Matthews,Liwei Chen,Jian Li 한국역학회 2022 Epidemiology and Health Vol.44 No.-

OBJECTIVES Job strain is positively associated with incident hypertension, while increasing leisure-time physical activity (LTPA) can reduce incident hypertension. However, the joint associations of job strain and LTPA with incident hypertension among United States workers have yet to be investigated. This study examined the independent and joint associations of job strain and LTPA with incident hypertension. METHODS This prospective cohort study (n=1,160) utilized data from the population-based Midlife in the United States study. The associations of job strain and LTPA at baseline with incident hypertension during follow-up were examined using Cox proportional hazards models. High job strain was derived from a combination of high job demands and low job control, and high LTPA was defined as engagement in moderate or vigorous LTPA at least once per week. RESULTS During 9,218 person-years of follow-up, the hypertension incidence rate was 30.6 (95% confidence interval [CI], 27.3 to 34.3) per 1,000 person-years. High job strain was associated with a higher risk for hypertension than low job strain (adjusted hazard ratio [aHR], 1.29; 95% CI, 1.00 to 1.67). High LTPA was associated with lower hypertension risk than low LTPA (aHR, 0.77; 95% CI, 0.60 to 0.98). Hypertension risk was higher among workers with high job strain and low LTPA than among those with low job strain and high LTPA (aHR, 1.70; 95% CI, 1.18 to 2.43). CONCLUSIONS Job strain and LTPA showed positive and inverse associations, respectively, with incident hypertension. The combination of high job strain and low LTPA was associated with the highest risk for hypertension.

Synthesis of Au@MoS2-CdS Ternary Composite Structure with Enhanced Photocatalytic Activity

Zhe Liu,Liwei Wang,Ruoping Li,Mingju Huang 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2019 NANO Vol.14 No.9

Au@MoS2-CdS, as ternary composite structure, was successfully synthesized by a facile process combining hydrothermal and seed-growth methods. The introduction of Au nanoparticles (NPs) into MoS2 spheres, forming a core–shell structure, demonstrats strong plasmonic absorption enhancement. The incorporation of CdS NPs into the Au@MoS2 core–shell structure further extends the absorption range of visible light and enhances exciton dissociation. The resultant composite structure exhibits the highest photocatalytic activity in photocatalytic degradation of rhodamine B (RhB) solution, compared with Au NPs, MoS2 spheres, Au@MoS2 core–shell and MoS2-CdS heterostructures. The above phenomena are supported by a series of characterization results such as SEM, TEM, XRD, EDS and UV-Vis, etc. Based on structural and morphological analyses, we propose the synthesis method of ternary composite structure photocatalysts, which is helpful for the synthesis of future multicomponent photocatalytic materials.

Phenolic acids in Panax ginseng inhibit melanin production through bidirectional regulation of melanin synthase transcription via different signaling pathways

Jianzeng Liu,Xiaohao Xu,Jingyuan Zhou,Guang Sun,Zhenzhuo Li,Lu Zhai,Jing Wang,Rui Ma,Daqing Zhao,Rui Jiang,Liwei Sun 고려인삼학회 2023 Journal of Ginseng Research Vol.47 No.6

Background: Our previous investigation indicated that the preparation of Panax ginseng Meyer(P. ginseng) inhibited melanogenesis. It comprised salicylic acid (SA), protocatechuic acid (PA), p-coumaricacid (p-CA), vanillic acid (VA), and caffeic acid (CA). In this investigation, the regulatory effects ofP. ginseng phenolic acid monomers on melanin production were assessed. Methods: In vitro and in vivo impact of phenolic acid monomers were assessed. Results: SA, PA, p-CA and VA inhibited tyrosinase (TYR) to reduce melanin production, whereas CA hadthe opposite effects. SA, PA, p-CA and VA significantly downregulated the melanocortin 1 receptor(MC1R), cycle AMP (cAMP), protein kinase A (PKA), cycle AMP-response element-binding protein (CREB),microphthalmia-associated transcription factor (MITF) pathway, reducing mRNA and protein levels ofTYR, tyrosinase-related protein 1 (TYRP1), and TYRP2. Moreover, CA treatment enhanced the cAMP, PKA,and CREB pathways to promote MITF mRNA level and phosphorylation. It also alleviated MITF proteinlevel in a-MSH-stimulated B16F10 cells, comparable to untreated B16F10, increasing the expression ofphosphorylation glycogen synthase kinase 3b (p-GSK3b), b-catenin, p-ERK/ERK, and p-p38/p38. Furthermore, the GSK3b inhibitor promoted p-GSK3b and p-MITF expression, as observed in CA-treatedcells. Moreover, p38 and ERK inhibitors inhibited CA-stimulated p-p38/p38, p-ERK/ERK, and p-MITFincrease, which had negative binding energies with MC1R, as depicted by molecular docking. Conclusion: P. ginseng roots' phenolic acid monomers can safely inhibit melanin production by bidirectionallyregulating melanin synthase transcription. Furthermore, they reduced MITF expression viaMC1R/cAMP/PKA signaling pathway and enhanced MITF post-translational modification via Wnt/mitogen-activated protein kinase signaling pathway.

Adjustable Multiple Relay Selection Based on Steady-State Mean Square Joint Error for Cooperative Communication

( Zhiyong Liu ),( Qinyu Zhang ),( Liwei Mu ) 한국인터넷정보학회 2016 KSII Transactions on Internet and Information Syst Vol.10 No.9

In this paper, an adjustable multiple relay selection (MRS) scheme for cooperative communication with amplify-and-forward (AF) relay under frequency selective channels is proposed. In the proposed scheme, the relays are ordered firstly by the steady-state mean square error (MSE), then the relays are sequentially selected out from N relays and the number of cooperating relays is adjusted dynamically according to the steady-state mean square joint error (MSJE). The aim of this work is to dynamically estimate the optimum number No of cooperating relays. Optimum means the minimum number of cooperating relays, No, achieving the minimum level of steady-state MSJE. Numerical results verify the analyses and show that the scheme can adaptively adjust the number of cooperating relays, and outperform conventional relay selection schemes. Hence, the proposed scheme provides better tradeoff between BER performance and spectral efficiency and to save more energy in cooperative wireless networks.

Synergistic catalysis of bifunctional polyacrylonitrile fiber for the synthesis of (E)-α,β-unsaturated esters from aldehydes by decarboxylative Doebner–Knoevenagel reaction

Pengyu Li,Liwei Mi,Yuanyuan Liu,Wenqin Zhang,Xian-Lei Shi 한국공업화학회 2020 Journal of Industrial and Engineering Chemistry Vol.81 No.-

A series of monofunctional and bifunctional polyacrylonitrilefiber catalysts have been successfullyprepared to catalyze the decarboxylative Doebner–Knoevenagel reaction of aldehydes and monoethylmalonate for the syntheses of the (E)-α,β-unsaturated esters. Among which, the catalyst PANPDFII/I showsthe best synergistic catalytic activity with high yields (89–96%), stereoselectivities (Z:E > 99:1) andreusability (up to 8 times). The influences of the N position on aminopyridine moiety, solvent andtemperature on the catalytic system were investigated in detail. This catalytic system can process well inhigher or lower polar organic solvents instead of moderate polar solvents, which is an interestingphenomenon in organic catalysis, and the reasons are explained in this work. Furthermore, a DMAP (4-dimethylaminopyridine) and piperazine synergistic catalytic mechanism in the micro-environment ofthefiber catalyst has been conceived to explain the high catalytic performance of this catalytic system. Besides, thefiber catalyst PANPDFII/I shows high application potential in industry for its good performancein scaled-up experiment, as well as its advantages of the easy preparation, high mechanical strength,flexibility and high stability in air.

Improved design method for line gear pair based on screw theory

Jiang Ding,Liwei Liu,Yuting Wei,Aiping Deng 대한기계학회 2022 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.36 No.4

The line gear (LG) is a novel gear mechanism based on conjugate space curve meshing theory. It is suitable for micro-mechanical systems due to its small size, light weight, and large transmission ratio. Since its invention, the LG pair has been studied from the perspective of differential geometry. To simplify the design process of the LG pair, we studied the LG pair from the innovative perspective of screw algebra. A unified screw coordinate was created for the LG pair, and velocity screws were established to derive its meshing equations. Moreover, the design equations of the center curves and contact curves were calculated for the driving line teeth and the driven line teeth, respectively. Finally, examples of LG pairs were fabricated for the kinematic performance tests, which indicated that the LG pairs designed according to screw theory were capable of performing a stable transmission.

Proteomic analysis of amino acid metabolism differences between wild and cultivated Panax ginseng

Sun, Hang,Liu, Fangbing,Sun, Liwei,Liu, Jianzeng,Wang, Manying,Chen, Xuenan,Xu, Xiaohao,Ma, Rui,Feng, Kai,Jiang, Rui The Korean Society of Ginseng 2016 Journal of Ginseng Research Vol.40 No.2

Background: The present study aimed to compare the relative abundance of proteins and amino acid metabolites to explore the mechanisms underlying the difference between wild and cultivated ginseng (Panax ginseng Meyer) at the amino acid level. Methods: Two-dimensional polyacrylamide gel electrophoresis and isobaric tags for relative and absolute quantitation were used to identify the differential abundance of proteins between wild and cultivated ginseng. Total amino acids in wild and cultivated ginseng were compared using an automated amino acid analyzer. The activities of amino acid metabolism-related enzymes and the contents of intermediate metabolites between wild and cultivated ginseng were measured using enzyme-linked immunosorbent assay and spectrophotometric methods. Results: Our results showed that the contents of 14 types of amino acids were higher in wild ginseng compared with cultivated ginseng. The amino acid metabolism-related enzymes and their derivatives, such as glutamate decarboxylase and S-adenosylmethionine, all had high levels of accumulation in wild ginseng. The accumulation of sulfur amino acid synthesis-related proteins, such as methionine synthase, was also higher in wild ginseng. In addition, glycolysis and tricarboxylic acid cycle-related enzymes as well as their intermediates had high levels of accumulation in wild ginseng. Conclusion: This study elucidates the differences in amino acids between wild and cultivated ginseng. These results will provide a reference for further studies on the medicinal functions of wild ginseng.