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Synthesis and Optical Properties of 2,13-Dibenzothiazol-2′-yldibenzo[b,k]-18-crown-6
HUANG, Zhi-Bin,KIM, Sung-Hong,SHI, Da-Qing,KANG, Tai-Jong,CHANG, Seung-Hyun WILEY-VCH Verlag 2008 Chinese journal of chemistry Vol.26 No.6
<P>A new crown ether of 2,13-dibenzothiazol-2′-yldibenzo[b,k]-18-crown-6 was synthesized from 2,13-diformyl- dibenzo[b,k]-18-crown-6 with 2-aminothiophenol. The binding behavior and the optical properties of the crown ether were examined through UV-visible spectroscopy and fluorescence spectroscopy. When complexed with Na<SUP>+</SUP>, K<SUP>+</SUP>, Rb<SUP>+</SUP> and Cs<SUP>+</SUP> ions, it led to intramolecular charge transfer and caused the changes of the fluorescence spectra. The protonation of the crown ether was also studied.</P>
( Yuan Wei ),( Zhi Peng Chen ),( Feng Chang Wu ),( Ji Ning Li ),( Yu Xian Shangguan ),( Fa Sheng Li ),( Qing Ru Zeng ),( Hong Hou ) 한국미생물 · 생명공학회 2015 Journal of microbiology and biotechnology Vol.25 No.8
Arbuscular mycorrhizal fungi (AMF) have great potential for assisting heavy metal hyperaccumulators in the remediation of contaminated soils. However, little information is available about the symbiosis of AMF associated with an antimony (Sb) accumulator plant under natural conditions. Therefore, the objective of this study was to investigate the colonization and molecular diversity of AMF associated with the Sb accumulator ramie (Boehmeria nivea) growing in Sb-contaminated soils. Four Sb mine spoils and one adjacent reference area were selected from Xikuangshan in southern China. PCR-DGGE was used to analyze the AMF community composition in ramie roots. Morphological identification was also used to analyze the species in the rhizosphere soil of ramie. Results obtained showed that mycorrhizal symbiosis was established successfully even in the most heavily polluted sites. From the unpolluted site Ref to the highest polluted site T4, the spore numbers and AMF diversity increased at first and then decreased. Colonization increased consistently with the increasing Sb concentrations in the soil. A total of 14 species were identified by morphological analysis. From the total number of species, 4 (29%) belonged to Glomus, 2 (14%) belonged to Acaulospora, 2 (14%) belonged to Funneliformis, 1 (7%) belonged to Claroideoglomus, 1 (7%) belonged to Gigaspora, 1 (7%) belonged to Paraglomus, 1 (7%) belonging to Rhizophagus, 1 (7%) belonging to Sclervocystis, and 1 (7%) belonged to Scutellospora. Some AMF sequences were present even in the most polluted site. Morphological identification and phylogenetic analysis both revealed that most species were affiliated with Glomus, suggesting that Glomus was the dominant genus in this AMF community. This study demonstrated that ramie associated with AMF may have great potential for remediation of Sb-contaminated soils.
Antitumor Activity of Histone Deacetylase Inhibitor Trichostatin A in Osteosarcoma Cells
Cheng, Dong-Dong,Yang, Qing-Cheng,Zhang, Zhi-Chang,Yang, Cui-Xia,Liu, Yi-Wen Asian Pacific Journal of Cancer Prevention 2012 Asian Pacific journal of cancer prevention Vol.13 No.4
Background: Histone deacetylase (HDAC) inhibitors have been reported to induce cell growth arrest, apoptosis and differentiation of tumor cells. The present study aimed to examine the effects of trichostatin A (TSA), one such inhibitor, on the cell cycle, apoptosis and invasiveness of osteosarcoma cells. Methods: MG-63 cells were treated with TSA at various concentrations. Then, cell growth and apoptosis were determined by 3-(4, 5-dimethyl-2-thiazolyl)-2H-tetrazolium bromide (MTT) and TUNEL assays, respectively; cell cycling was assessed by flow cytometry; invasion assays were performed with the transwell Boyden Chamber system. Results: MTT assays revealed that TSA significantly inhibited the growth of MG-63 cells in a concentration and time dependent manner. TSA treated cells demonstrated morphological changes indicative of apoptosis and TUNEL assays revealed increased apoptosis of MG-63 cells after TSA treatment. Flow cytometry showed that TSA arrested the cell cycle in G1/G2 phase and annexin V positive apoptotic cells increased markedly. In addition, the invasiveness of MG-63 cells was inhibited by TSA in a concentration dependent manner. Conclusion: Our findings demonstrate that TSA inhibits the proliferation, induces apoptosis and inhibits invasiveness of osteosarcoma cells in vitro. HDAC inhibitors may thus have promise to become new therapeutic agents against osteosarcoma.
Seismic Response of Resilient Steel Frame with Self-Centering SMA Brace
Shujun Hu,Liqing Chang,Bo Zhang,Sizhi Zeng,Fenghua Tang,Qing Zhi 한국강구조학회 2023 International Journal of Steel Structures Vol.23 No.6
An innovative self-centering shape memory alloy (SMA) brace aiming at improving the seismic performance and self-centering capacity of steel frame structures is proposed in this paper. A series of cyclic loading tests with six self-centering SMA brace (SC-SMAB) specimens was carried out to investigate the effects of SMA area, bolt torque and initial SMA force on the hysteresis curves, energy dissipation and self-centering capacity. In addition, based on the experimental results, a numerical model of SC-SMAB with the improved Graesser and Bouc–Wen model was established and validated. Three different single-bay plan configurations of 9 storey steel frames including bare steel frame (BSF), steel frame with slip braces (SF-SB) and steel frame with SC-SMABs (SF-SCB) were analyzed to evaluate the seismic response. The test results show that the SC-SMAB with the bolt torque of 10 N M and initial SMA force of 5 kN has the maximum bearing force and self-centering capacity ratio. The established numerical model can accurately predict the seismic performance of the SC-SMAB. The inter-story drift ratio, roof displacement and roof acceleration of SF-SCB are lower than those of the BSF and SF-SB evidently, which decrease by 62.21%, 29.46% and 28.36% respectively from BSF. The hysteresis curve of SC-SMAB in the steel frame has nearly ideal flag-shape with high bearing force, good energy dissipation capacity, small residual deformation and outstanding re-centering capacity.
Sha Liao,Shi-Yong Fan,Qin Liu,Chang-Kun L,Jia Chen,Jing-Lai Li,Zhi-Wei Zhang,Zhen-Qing Zhang,Bo-Hua Zhong,Jian-Wei Xie 대한약학회 2014 Archives of Pharmacal Research Vol.37 No.11
Chronic hepatitis B virus (HBV) infection maylead to liver cirrhosis and hepatocellular carcinoma, butfew drugs are available for its treatment. Acyclic nucleosidephosphonates (ANPs) have remarkable antivirusactivities but are not easily absorbed from the gastrointestinaltract and accumulate in the kidneys, resulting innephrotoxicity. Therefore, there is a need to find effectiveliver site-specific prodrugs. The dipivaloyloxymethyl esterof 9-(2-phosphonylmethoxyethyl)adenine (PMEA)—adefovirdipivoxil (ADV)—is a first-line therapy drug forchronic hepatitis B with a low therapeutic index because ofrenal toxicity and low hepatic uptake. In this study, a seriesof PMEA derivatives were synthesized to enhance plasmastability and liver release. The metabolic stability of ADV(Chemical I) and its two analogues (Chemicals II and III)was evaluated in rat plasma and liver homogenate in vitro. An ion-pair reverse-phase HPLC–UV method and a hybridion trap and high-resolution time-of-flight mass spectrometry(LC-IT-TOF-MS) were used to evaluate the degradationrate of the analogues and to identify their intermediatemetabolites, respectively. Chemicals I and II were hydrolyzedby cleavage of the C–O bond to give monoesters. Sufficient enzymatic activation in the liver homogenatethrough a relatively simple metabolic pathway, in additionto a favorable stability profile in rat plasma, made ChemicalII an optimal candidate. Next, six analogues based onthe structure of Chemical II were synthesized and evaluatedin plasma and liver homogenate. Compared toChemical II, these compounds generated less active PMEAlevels in rat liver homogenate. Therefore, chemical modificationof Chemical II may lead to new promising PMEAderivatives with enhanced plasma stability and liveractivation.