Influences of Bridge Group on Thermal and Mechanical Properties of Epoxy Resins

Liu Yuan,Zhao Jun,Liu Ai-Qin,Liu Xiao-Qing,Luo Jun 한국고분자학회 2020 폴리머 Vol.44 No.4

In order to obtain thermosetting epoxy resin, it is the prerequisite condition that the epoxy precursor must contain at least two epoxy groups. Thus, bridge group is needed to link the epoxy groups, and naturally, the chemical structure of the bridge group may also influence the thermomechanical performances of the cured epoxy resin. However, literature about the effects of bridge group on properties of cured epoxy is seldom published. To fill the gap, three model epoxy monomers containing different bridge groups have been synthesized from 4,4"-dihydroxydiphenyl, 1,1-bis(4- hydroxyphenyl)cyclohexane and bisphenol A in this work. After chemical structure confirmation, all of the monomers are cured by methylhexahydrophthalic anhydride (HMMPA), and the properties of the obtained cured network are evaluated by differential scanning calorimetry (DSC), dynamic thermomechanical analysis (DMA), tensile test and scanning electron microscope (SEM). The results show that bulky bridge group can effectively increase the glass transition temperature, enhance the tensile strength, and enlarge elongation at break of the cured epoxy resin.

Tick-Borne Pathogens in Ixodid Ticks from Poyang Lake Region, Southeastern China

Wei Qing Zheng,Xue Nan Xuan,Ren Long Fu,Hui Ying Tao,Yang Qing Liu,Xiao Qing Liu,Dong Mei Li,Hong Mei Ma,Hai Ying Chen 대한기생충학열대의학회 2018 The Korean Journal of Parasitology Vol.56 No.6

Flavonoid Glycosides and Potential Antivirus Activity of Isolated Compounds from the Leaves of Eucalyptus citriodora

Zhong-Liu Zhou,Wen-Qing Yin,Xiao-Peng Zou,Dan-Ying Huang,Cui-Liu Zhou,Lian-Mei Li,Ke-Cheng Chen,Zi-Ying Guo,San-Qing Lin 한국응용생명화학회 2014 Applied Biological Chemistry (Appl Biol Chem) Vol.57 No.6

The extraction and solvent partition of the leaves ofEucalyptus citriodora, and repeated column chromatography for n-BuOH fraction yielded a new flavonoid glycoside, citrioside C (1),along with three known flavonoid glycosides (2-4). The latter wereidentified with kaempferol-3-O-β-D-glucopyranosyl (12)-α-L-rhamnoside(2), kaempferol-3-O-α-L-rhamnoside (3), and quercetin-3-O-α-Lrhamnoside(4). Their chemical structures were identified on thebasis of spectroscopic data analyses including NMR, MS, UV, andIR. All constitutents were isolated for the first time from the leavesof Eucalyptus citriodora. The potential antivirus activity of all theisolated compounds was evaluated. Compound 4 showed potentantiviral activity against respiratory syncytial virus with 50%inhibition concentration (IC50) value of 1.9 μg/mL and selectiveindex value of 9.8.

Flavonoid Glycosides and Potential Antivirus Activity of Isolated Compounds from the Leaves of Eucalyptus citriodora

Zhou, Zhong-Liu,Yin, Wen-Qing,Zou, Xiao-Peng,Huang, Dan-Ying,Zhou, Cui-Liu,Li, Lian-Mei,Chen, Ke-Cheng,Guo, Zi-Ying,Lin, San-Qing 한국응용생명화학회 2014 Applied Biological Chemistry (Appl Biol Chem) Vol.57 No.6

The extraction and solvent partition of the leaves of Eucalyptus citriodora, and repeated column chromatography for n-BuOH fraction yielded a new flavonoid glycoside, citrioside C (1), along with three known flavonoid glycosides (2-4). The latter were identified with kaempferol-3-O-${\beta}$-$\small{D}$-glucopyranosyl (12)-${\alpha}$-$\small{L}$-rhamnoside (2), kaempferol-3-O-${\alpha}$-$\small{L}$-rhamnoside (3), and quercetin-3-O-${\alpha}$-$\small{L}$-rhamnoside (4). Their chemical structures were identified on the basis of spectroscopic data analyses including NMR, MS, UV, and IR. All constitutents were isolated for the first time from the leaves of Eucalyptus citriodora. The potential antivirus activity of all the isolated compounds was evaluated. Compound 4 showed potent antiviral activity against respiratory syncytial virus with 50% inhibition concentration ($IC_{50}$) value of $1.9{\mu}g/mL$ and selective index value of 9.8.

Protective effects of vitamins C and E on dichlorodiphenyltrichloroethane-induced genotoxicity and hepatotoxicity in human liver cells

Xiao Ting Jin,Li Song,Xiang Yuan Liu,Hang Qing Li,Long Cheng,Zhuo Yu Li1,,Z. Y. Li 대한독성 유전단백체 학회 2017 Molecular & cellular toxicology Vol.13 No.2

Dichlorodiphenoxytrichloroethane (DDT), a persistent organic pollutant and hepatotoxicant, is used to control the malaria. However, scarce information exists on relevant effective inhibitors of DDT’ toxicity. The aim of this study was to investigate protective effects of natural antioxidants vitamin C (VC) or/and vitamin E (VE) on p,pʹ-DDT-induced genotoxicity and hepatotoxicity in human liver cells. p,pʹ-DDT exposure increased levels of chromatin condensation, comet parameter, micronucleus induction and DPC coefficient of HL-7702 cells in a dose-dependent manner. Also, an increase in mRNA levels of CYP1A1 as well as CYP3A4, and a decrease in UGT along with GST were observed. Interestingly, supplementation with VC or/and VE prevented p,pʹ-DDT-caused alterations in DNA damage and phase metabolism gene expressions, and the combination of VC and VE had a more protective effect than VC or VE alone. These findings illustrated that VC or/and VE could be beneficial for the alleviation of p,pʹ-DDT-incurred toxicity in human liver cells.

Associations Between RASSF1A Promoter Methylation and NSCLC: A Meta-analysis of Published Data

Liu, Wen-Jian,Tan, Xiao-Hong,Guo, Bao-Ping,Ke, Qing,Sun, Jie,Cen, Hong Asian Pacific Journal of Cancer Prevention 2013 Asian Pacific journal of cancer prevention Vol.14 No.6

Background: RASSF1A has been reported to be a candidate tumor suppressor in non-small cell lung cancer (NSCLC). However, the association between RASSF1A promoter methylation and NSCLC remains unclear, particularly in regarding links to clinicopathologic features. Methods: Eligible studies were identified through searching PubMed, EMBASE, Cochrane Library and China National Knowledge Infrastructure (CNKI) databases. Studies were pooled and odds ratios (ORs) with corresponding confidence intervals (CIs) were calculated. Funnel plots were also performed to evaluate publication bias. Results: Nineteen studies involving 2,063 cases of NSCLC and 1,184 controls were included in this meta-analysis. A significant association was observed between RASSF1A methylation and NSCLC in the complete data set (OR = 19.42, 95% CI: 14.04-26.85, P < 0.001). Pooling the control tissue subgroups (heterogeneous/autologous) gave pooled ORs of 32.4 (95% CI, 12.4-84.5) and 17.7 (95% CI, 12.5-25.0) respectively. Racial subgroup (Caucasian/Asian) analysis gave pooled ORs of 26.6 (95% CI, 10.9-64.9) and 20.9 (95% CI, 14.4-30.4) respectively. The OR for RASSF1A methylation in poorly-differentiated vs. moderately/well-differentiated NSCLC tissues was 1.88 (95% CI, 1.32-2.68, P<0.001), whereas there were no significant differences in RASSF1A methylation in relation to gender, pathology, TNM stage and smoking behavior among NSCLC cases. Conclusion: This meta-analysis suggests a significant association between RASSF1A methylation and NSCLC, confirming the role of RASSF1A as a tumor suppressor gene. Large-scale and well-designed case-control studies are needed to validate the associations identified in the present meta-analysis.

Wheel tread defect detection for high-speed trains using FBG-based online monitoring techniques

Liu, Xiao-Zhou,Ni, Yi-Qing Techno-Press 2018 Smart Structures and Systems, An International Jou Vol.21 No.5

The problem of wheel tread defects has become a major challenge for the health management of high-speed rail as a wheel defect with small radius deviation may suffice to give rise to severe damage on both the train bogie components and the track structure when a train runs at high speeds. It is thus highly desirable to detect the defects soon after their occurrences and then conduct wheel turning for the defective wheelsets. Online wheel condition monitoring using wheel impact load detector (WILD) can be an effective solution, since it can assess the wheel condition and detect potential defects during train passage. This study aims to develop an FBG-based track-side wheel condition monitoring method for the detection of wheel tread defects. The track-side sensing system uses two FBG strain gauge arrays mounted on the rail foot, measuring the dynamic strains of the paired rails excited by passing wheelsets. Each FBG array has a length of about 3 m, slightly longer than the wheel circumference to ensure a full coverage for the detection of any potential defect on the tread. A defect detection algorithm is developed for using the online-monitored rail responses to identify the potential wheel tread defects. This algorithm consists of three steps: 1) strain data pre-processing by using a data smoothing technique to remove the trends; 2) diagnosis of novel responses by outlier analysis for the normalized data; and 3) local defect identification by a refined analysis on the novel responses extracted in Step 2. To verify the proposed method, a field test was conducted using a test train incorporating defective wheels. The train ran at different speeds on an instrumented track with the purpose of wheel condition monitoring. By using the proposed method to process the monitoring data, all the defects were identified and the results agreed well with those from the static inspection of the wheelsets in the depot. A comparison is also drawn for the detection accuracy under different running speeds of the test train, and the results show that the proposed method can achieve a satisfactory accuracy in wheel defect detection when the train runs at a speed higher than 30 kph. Some minor defects with a depth of 0.05 mm~0.06 mm are also successfully detected.

Learning with Information Entropy Method for Transportation Image Retrieval

Liu Xiao-jun,Li Qing-ling,Li Yong-jian,Li Jun-yi 보안공학연구지원센터 2015 International Journal of Multimedia and Ubiquitous Vol.10 No.7

As a new learning framework, Multi-Instance learning is labeled recently and has successfully found application in vision classification. A novel Multi-instance bag generating method is presented in this paper on basis of Gaussian Mixed Model. The generated GMM model composes not only color but also the locally stable unchangeable components. It is frequently named as MI bag by researchers. Besides, another method called Agglomerative Information Bottleneck clustering is applied to replace the MIL problem with the help of single-instance learning ones. Meanwhile, single-instance classifiers are employed for classification. Finally, ensemble learning is adopted to strengthen classifiers’ generalization ability of RBM (Restricted Boltzmann Machine) as the base classifier. On the basis of large-scale datasets, this method is tested and the corresponding result shows that our method provides high accuracy and good performance for image annotation, feature matching and example-based object-classification.

Gene Microarray Assessment of Multiple Genes and Signal Pathways Involved in Androgen-dependent Prostate Cancer Becoming Androgen Independent

Liu, Jun-Bao,Dai, Chun-Mei,Su, Xiao-Yun,Cao, Lu,Qin, Rui,Kong, Qing-Bo Asian Pacific Journal of Cancer Prevention 2014 Asian Pacific journal of cancer prevention Vol.15 No.22

To study the gene expression change and possible signal pathway during androgen-dependent prostate cancer (ADPC) becoming androgen-independent prostate cancer (AIPC), an LNCaP cell model of AIPC was established using flutamide in combination with androgen-free environment inducement, and differential expression genes were screened by microarray. Then the biological process, molecular function and KEGG pathway of differential expression genes are analyzed by Molecule Annotation System (MAS). By comparison of 12,207 expression genes, 347 expression genes were acquired, of which 156 were up-ragulated and 191 down-regulated. After analyzing the biological process and molecule function of differential expression genes, these genes are found to play crucial roles in cell proliferation, differntiation, cell cycle control, protein metabolism and modification and other biological process, serve as signal molecules, enzymes, peptide hormones, cytokines, cytoskeletal proteins and adhesion molecules. The analysis of KEGG show that the relevant genes of AIPC transformation participate in glutathione metabolism, cell cycle, P53 signal pathway, cytochrome P450 metabolism, Hedgehog signal pathway, MAPK signal pathway, adipocytokines signal pathway, PPAR signal pathway, TGF-${\beta}$ signal pathway and JAK-STAT signal pathway. In conclusion, during the process of ADPC becoming AIPC, it is not only one specific gene or pathway, but multiple genes and pathways that change. The findings above lay the foundation for study of AIPC mechanism and development of AIPC targeting drugs.

A Theoretical Study on the Mechanism of Decarboxylations for Hydroxymandelate Synthase

Qing-An Qiao,Qiuxian Li,Changchun Liu,Xiao Sun,Honglan Cai,Lixiang Sun,Huayang Wang 대한화학회 2017 Bulletin of the Korean Chemical Society Vol.38 No.6

Hydroxymandelate synthase is one type of alpha-keto acid-dependent oxygenases and plays an important role in the biosynthesis of hydroxyphenyl-pyruvate. The ferrous and ferryl intermediates in the reaction were considered to be very important in the DNA repair process. The mechanism of hydroxymandelate synthase was investigated by a theoretical method based on B3LYP/LACVP*. The data indicated that each decarboxylation went through a process of direct dioxygen insertion. The first oxidative decarboxylation experienced only one transition state, while there were two potential pathways for the second decarboxylation process. The calculation data showed that the stepwise one was favored to the concerted one due to the lower energy barrier. The process to form the iron-superoxide was the rate-limiting step. After two consecutive decarboxylations, a proton transfer reaction was needed to obtain the target products. Two possible transition states were found out to achieve this step. The one with a six-membered ring structure was preferred because of the lower activation energy. In addition, several ferryl species with high spins were captured in the whole process, which could be supplied as requisite substrates for DNA repair reaction.