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On D-admissibility Conditions of Singular Systems
Lixin Gao,Wenhai Chen 대한전기학회 2007 International Journal of Control, Automation, and Vol.5 No.1
In this paper, we first establish DL-admissibility and DR-admissibility conditions for singular systems. The admissibility conditions expressed as Lyapunov type inequalities extend the existed results of normal systems to singular systems. As special cases the admissibility conditions of the continuous-time and the discrete-time singular systems can be obtained directly. The results established in this paper can be applied to solve the problems of eigenvalue assignment, regional pole-placement and robust control etc.
Leader-following Consensus Problem with an Accelerated Motion Leader
Lixin Gao,Xinjian Zhu,Wenhai Chen 제어·로봇·시스템학회 2012 International Journal of Control, Automation, and Vol.10 No.5
In this paper, we consider a multi-agent consensus problem with an accelerated motion leader and variable interconnection topology. To track such a leader, a neighbor-based local controller together with a neighbor-based state-estimation rule is proposed for each second-order follower-agent. The neighbor-based estimation rule is used to estimate the acceleration of the leader, which is assumed not to be measured by follower agents directly. By constructing a parameter-dependent common Lya-punov function, a sufficient condition is established to guarantee that each agent can follow the leader although the leader moves with an unknown time-variant acceleration. Moreover, the tracking error is estimated for the case that the unknown acceleration part of the leader has bounded derivative. Finally, a numerical example is given to illustrate the obtained result.
Molecular Cloning and Expression of Grass Carp MyoD in Yeast Pichia pastoris
Wang, Lixin,Bai, Junjie,Luo, Jianren,Chen, Hong,Ye, Xing,Jian, Qing,Lao, Haihua Korean Society for Biochemistry and Molecular Biol 2007 Journal of biochemistry and molecular biology Vol.40 No.1
MyoD, expressed in skeletal muscle lineages of vertebrate embryo, is one of muscle-specific basic helix-loop-helix (bHLH) transcription factors, which plays a key role in the determination and differentiation of all skeletal muscle lineages. In this study, a cDNA of grass carp MyoD was cloned and characterized from total RNA of grass carp embryos by RT-PCR. The full-length cDNA of grass carp MyoD is 1597 bp. The cDNA sequence analysis reveals an open reading frame of 825 bp coding for a protein of 275 amino acids, which includes a bHLH domain composed of basic domain (1-84th amino acids) and HLH domain (98-142th amino acids), without signal peptide. Then the MyoD cDNA of grass carp was cloned to yeast expression vector pPICZ$\alpha$A and transformed into P. pastoris GS115 strain, the recombinant MyoD protein with a molecular weight of about 31KD was obtained after inducing for 2d with 0.5% methanol in pH 8.0 BMGY medium, and the maximum yield was about 250 mg/L in shaking-flask fermentation. The results were expected to benefit for further studies on the crystal structure and physiological function of fish MyoD.
Systematic equity risk change around convertible debt offerings
Lifang Chen,Lixin Xu 인하대학교 정석물류통상연구원 2009 인하대학교 정석물류통상연구원 학술대회 Vol.2009 No.10
This study investigates Systematic Equity Risk Change of a firm when it issues convertible bonds by studying the change in beta before and after the issuance of convertible bonds. Descriptive statistics provide the evidence that the systematic equity risk declines slightly after a firm has issued convertible debt, while the systematic equity risk was low both before and after issuance. However, both the T test and Wilcoxon signed-rank test of the paired-samples show that there appears to be no significant change in the systematic equity risk after a firm has issued convertible bonds. Although the conclusion is different from previous studies, it is consistent with and gives further support to the conjecture that firms try to stabilize the level of systematic risk of their common stock. Moreover, our results have implications for existing theories and suggest that it is important to consider possible risk changes when examining the issuance effects of offering convertible bonds.
Study of a Rapid Detection Method for Protein Content in Milk and Development of Detection Equipment
Liu Zhongfu,Chen Xingwen,Shi Lixin 보안공학연구지원센터 2015 International Journal of Multimedia and Ubiquitous Vol.10 No.12
Among the nutrients in milk, protein content is a core indicator for measuring the quality of milk. Therefore, to explore a rapid detection method for milk protein content and develop rapid detection equipment for protein ingredient can provide reference for quality analysis and quality control of the production process. In this paper, different dairy protein detection methods are analyzed, the working principles of Micro-Kjeldahl method are studied, and a new type of milk protein content detector is designed based on the Micro-Kjeldahl nitrogen determination method. As for this instrument, LPC2214 microcontroller with ARM structure is taken as the control core, with the functions such as adding certain volume of lye, adding certain volume of boric acid absorption liquid, automatically generating steam required, automatically titrating hydrochloric acid solution, accurately determining the endpoint, conveniently setting parameters and so on, which realizes the digital and intelligent design in determining the protein content in dairy products. Experimental results show that the system is stable, with broad application prospects.
Liang Yang,Lin Chen,Lixin Shen,Michael Surette,Kangmin Duan 한국미생물학회 2011 The journal of microbiology Vol.49 No.1
Resistance-Nodulation-Cell Division (RND) pumps play important roles in bacterial resistance to antibiotics. Pseudomonas aeruginosa is an important human pathogen which exhibits high level resistance to antibiotics. There are total of 12 RND pumps present in the P. aeruginosa PAO1 genome. The recently characterized MuxABC-OpmB system has been shown to play a role in resistance to novobiocin, aztreonam, macrolides,and tetracycline in a multiple knockout mutation. In this study, we examined the expression levels of all the 12 RND pump gene clusters and tested the involvement of MuxABC-OpmB in pathogenicity. The results indicated that in addition to the four known constitutively expressed RND pumps, mexAB-oprM, mexGHIopmD,mexVW, and mexXY, relatively high levels of expression were observed with mexJK and muxABCopmB in the conditions tested. Inactivation of muxA in the muxABC-opmB operon resulted in elevated resistance to ampicillin and carbenicillin. The mutant also showed attenuated virulence in both Brassica rapa pekinensis and Drosophila melanogaster infection models. The decreased virulence at least in part was due to decreased twitching motility in the mutant. These results indicate that the RND pump MuxABC-OpmB is associated with ampicillin and carbenicillin susceptibility and also involved in pathogenesis in P. aeruginosa.
TIEJUN ZHAO,HEZHONG CHEN,LIXIN YANG,HAI JIN,ZHIGANG LI,LIN HAN,FANGLIN LU,ZHIYUN XU 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2013 NANO Vol.8 No.2
Oral chemotherapy is a great way to cancer treatment because it is less stressful being that the patient will have less hospital visits and can still maintain a close relationship with health care professionals. In this research, three types of nanoparticle formulation from commercial PCL and self-synthesized TPGS-b-(PCL-ran-PGA) diblock copolymer were fabricated for oral delivery of antitumor agents, including DDAB-modified PCL nanoparticles, unmodified TPGS-b-(PCL-ran-PGA) nanoparticles and DDAB-modified TPGS-b-(PCL-ran-PGA) nanoparticles. Firstly, the TPGS-b-(PCL-ran-PGA) diblock copolymer was synthesized and characterized. DDAB was adopted to increase retention time at the cell surface, thus increasing the chances of nanoparticle uptake by the gastrointestinal mucosa and improving drug absorption. The TPGS-b-(PCL-ran-PGA) nanoparticles were found by FESEM of spherical shape and around 200 nm in diameter. The surface charge of TPGS-b-(PCL-ran-PGA) nanoparticles was reversed from anionic to cationic after DDAB modification. The DDAB-modified TPGS-b-(PCL-ran-PGA) nanoparticles have significantly higher level of the cell uptake than that of DDAB-modified PCL nanoparticles and unmodified TPGS-b-(PCL-ran-PGA) nanoparticles. In vitro cell viability studies showed advantages of the DDAB-modified TPGS-b-(PCL-ran-PGA) nanoparticles over Taxotere® in terms of cytotoxicity against A549 cells. In conclusion, oral chemotherapy by DDAB-modified TPGS-b-(PCL-ran-PGA) nanoparticle formulation may provide a promising outcome for lung cancer patients.