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Synthesis of (2-pyridyl)-Acetyl Chitosan and Its Antioxidant Activity
Li, Rong-Chun Korean Chemical Society 2011 대한화학회지 Vol.55 No.5
In this paper, chloracetyl chitosan (CACTS) was prepared at first. In the molecules of CACTS, there are active chlorine groups, which can take part in other reactions. Thus, number of chitosan derivatives will be obtained after chlorine is substituted. Choosing pyridine as the active group, a novel water-soluble chitosan derivative, (2-pyridyl)-acetyl chitosan (PACTS) was obtained and its antioxidant activity against hydroxyl radicals and superoxide radicals was assessed. The results indicated that PACTS had better antioxidant activity than that of chitosan, carboxymethyl chitosan (CMCTS), hydroxypropyl chitosan (HPCTS), and Vitamin C. And the $IC_{50}$ values against hydroxyl radicals and superoxide radicals were 0.31 mg/mL and 0.21 mg/mL, respectively.
Yong Chun Li,Fan Rong Meng,Chun Yan Zhang,Ning Zhang,Ming Shan Sun,Jiang Ping Ren,Hong Bin Niu,Xiang Wang,Jun Yin 한국식물학회 2012 Journal of Plant Biology Vol.55 No.5
To understand better the mechanisms that regulate the water stress response in wheat, we conducted a comparative analysis of transcript profiles in roots from two wheat genotypes -- drought-tolerant ‘Luohan No. 2’ (LH)and drought-susceptible ‘Chinese Spring’ (CS). In LH roots,3831 transcripts displayed changes in expression of at least two-fold over the well-watered control when drought treatment was applied. Of these, 1593 were induced while 2238 were repressed. Relatively fewer transcripts were drought-responsive in CS; i.e., 1404 transcripts were induced and 1493 were repressed. In common between LH and CS,569 transcripts were induced and 424 transcripts were repressed. In all, 689 transcripts (757 probe sets) identified from LH and 537 transcripts (575 probe sets) from CS were annotated and classified into 10 functional categories. Among those annotated transcripts from LH and CS that had fold-change ratios of at least 4, 92 induced transcripts were common to both, while 23 transcripts were specifically induced in LH. Gene ontology analysis of these induced genes showed highly significant enrichment for multiple terms related to abiotic stimuli, organic acid biosynthesis,and lipid metabolism. This suggests that these gene groups play important roles during the stress response in LH and CS, and might also be responsible for differences in drought tolerance between those genotypes.
Li Zhang,Chun-Chun Li,You-Rong Li,Chun-Mei Wu 대한기계학회 2019 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.33 No.1
This study aims to improve the thermo-economic performance of the subcritical organic Rankine cycle (ORC). Accordingly, an economical evaluation and the simultaneous multiparametric optimization on the subcritical ORC system for recovering low-grade waste heat of flue gas were conducted using electricity production cost (EPC) as the evaluation indicator. Results show that the optimum evaporating and condensing temperatures are mainly influenced by the inlet temperatures of flue gas and cooling fluid, respectively. High critical temperature of working fluids indicates high thermal-economic performance of the ORC system for 19 kinds of selected working fluids. Furthermore, the optimum pinch point temperature difference of evaporator decreases and that of condenser increases with the variation in the critical temperature of working fluids, but the optimum condensing temperature is unchanged. On the basis of a large number of calculation data, the correlations among the optimum cycle and external operating parameters of the subcritical ORC are proposed. These correlations can guide the engineering design of the subcritical ORC system.
Tumor Necrosis Factor-α Gene Polymorphisms and Risk of Oral Cancer: Evidence from a Meta-analysis
Chen, Fang-Chun,Zhang, Fan,Zhang, Zhi-Jiao,Meng, Si-Ying,Wang, Yang,Xiang, Xue-Rong,Wang, Chun,Tang, Yu-Ying Asian Pacific Journal of Cancer Prevention 2013 Asian Pacific journal of cancer prevention Vol.14 No.12
Numerous studies have been conducted regarding association between TNF-${\alpha}$ and oral cancer risk, but the results remain controversial. The present meta-analysis is performed to acquire a more precise estimation of relationships. Databases of Pubmed, the Cochrane library and the China National Knowledge Internet (CNKI) were retrieved until August 10, 2013. Pooled odds ratios (ORs) and 95% confidence intervals (95% CIs) were calculated with fixed- or random-effect models. The heterogeneity assumption was assessed by I-squared test. Among the eight included case-control studies, all were focused on TNF-${\alpha}$-308G>A and four also concerned the TNF-${\alpha}$-238G>A polymorphism. It was found that oral cancer risk were significant decreased with the TNF-${\alpha}$-308G>A polymorphism in the additive genetic model (GG vs. AA, OR=0.19, 95% CI: [0.04, 1.00], P=0.05, I2=68.9%) and the dominant genetic model (GG+GA vs. AA, OR=0.22, 95% CI: [0.06, 0.82], P=0.03, I2=52.4%); however, no significant association was observed in allele contrast (G vs. A, OR=0.70, 95% CI: [0.23, 2.16], P=0.54, I2=95.9%) and recessive genetic models (GG vs. GA+AA, OR=0.72, 95% CI: [0.33, 1.57], P=0.41, I2=93.1%). For the TNF-${\alpha}$-238G>A polymorphism, significant associations with oral cancer risk were found in the allele contrast (G vs. A, OR=2.75, 95% CI: [1.25, 6.04], P=0.01, I2=0.0%) and recessive genetic models (GG vs. GA+AA, OR=2.23, 95%CI: [1.18, 4.23], P=0.01, I2=0.0%). Conclusively, this meta-analysis indicates that TNF-${\alpha}$ polymorphisms may contribute to the risk of oral cancer. Allele G and the GG+GA genotype of TNF-${\alpha}$-308G>A may decrease the risk of oral cancer, while allele G and the GG genotype of TNF-${\alpha}$-238G>A may cause an increase.
Enhancement of Haloacetate Dehalogenase Production by Strain Mutation and Condition Optimization
Chun-jiao Lin,Li-rong Yang,Gang Xu,Jian-ping Wu 한국생물공학회 2011 Biotechnology and Bioprocess Engineering Vol.16 No.5
Enhancement of the activity of an inducible chloroacetate dehalogenase was carried out by efficient and safe mutation with UV and microwave irradiation along with optimization of culture conditions. First, a stable mutant of Pseudomonas sp. CGMCC 3267-MW6 with chloroacetate dehalogenase activity of 2.77 U/mL (3-fold higher activity than the wild strain) was produced by mutation. The maximum activity of this inducible enzyme was measured as 29.41 U/mL when Pseudomonas sp. CGMCC 3267-MW6 was cultured with 4 g/L 3-hydroxybutyrate for 12 h followed by 40 mM 3-chlorobutyrate for an additional 20 h. Production of the enzyme was found to be associated with growth of the bacterium. According to these results, we determined that the optimum inducer of chloroacetate dehalogenase activity would be a hard degradable substrate. The optimum auxiliary carbon source would be the primary metabolite of the substrate or the precursor of the metabolite. The optimum time of inducer supplementation would be during the middle stage of exponential phase. The optimum concentration of substrate would be sufficient but would not induce inhibition. Finally, the optimum collection time would be at the later stage of exponential phase. This work provides further knowledge of chloroacetate dehalogenase and the optimization of inducible enzyme production.
Inorganic-organic Hybrid Nanoparticles and Their Application on PET Fabrics for UV Protection
Chunli Li,Rong Li,Xuehong Ren 한국섬유공학회 2020 Fibers and polymers Vol.21 No.2
In this paper, we reported the synthesis of TiO2/γ-(methacryloyloxy)propyltrimethoxysilane (KH570) hybrid nanoparticles with simple and mild condition at room temperature. The as-prepared TiO2/KH570 hybrid nanoparticles were characterized by FT-IR, XRD, SEM, EDS, and XPS. The hybrid nanoparticles were coated onto the surfaces of polyethylene terephthalate (PET) fabrics by pad-dry-cure (PDC) process. The morphology, structural, and chemical composition of the coated fabrics were analyzed by SEM, EDS, and XPS. The ultraviolet protection factor (UPF) was used to evaluate the UV protection property of PET fabrics. The coated PET fabric exhibited good UV resistance abilities with a UPF value of 50+. The air permeability of the coated PET fabrics decreased significantly compared with the original PET fabrics. The coated PET fabrics also showed good washing stability. The coated fabrics had an excellent protective effect against ultraviolet rays after exposure to ultraviolet light for a period of time. The PDC process only caused a small degree loss of the tensile strength of the coated PET fabrics.
Chun Wu,Zhe Chen,Rong Qi,Ralph Kennel 전력전자학회 2016 JOURNAL OF POWER ELECTRONICS Vol.16 No.4
To decouple the secondary saliencies in sensorless permanent magnet synchronous machine (PMSM) drives, a repetitive control (RC) in the angle domain is proposed. In this paper, the inductance model of a concentrated windings surface-mounted PMSM (cwSPMSM) with strong secondary saliencies is developed. Due to the secondary saliencies, the estimated position contains harmonic disturbances that are periodic relative to the angular position. Through a transformation from the time domain to the angle domain, these varying frequency disturbances can be treated as constant periodic disturbances. The proposed angle-domain RC is plugged into an existing phase-locked loop (PLL) and utilizes the error of the PLL to generate signals to suppress these periodic disturbances. A stability analysis and parameter design guidelines of the RC are addressed in detail. Finally, the proposed method is carried out on a cwSPMSM drive test-bench. The effectiveness and accuracy are verified by experimental results.