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101.
102.
Yeong‐Tarng Shieh Gin‐Lung Liu Yawo‐Kuo Twu Tzong‐Liu Wang Chien‐Hsin Yang 《Journal of Polymer Science.Polymer Physics》2010,48(2):145-152
Effects of carbon nanotubes (CNT) on the dynamic mechanical property, thermal property, and crystal structure of poly(L ‐lactic acid) (PLLA) were investigated. Dynamic mechanical analysis (DMA) found that CNT via grafting modification with PLLA (CNT‐g‐PLLA) could result in effective reinforcing effects. Tan δ of DMA found that CNT‐g‐PLLA was compatible with the PLLA matrix, giving a single Tg of the composite with a higher CNT‐g‐PLLA loading giving a higher Tg of the composite. Wide angle X‐ray diffraction (WAXD) data demonstrated that CNT could assist the disorder‐to‐order (α′‐to‐α) transition in PLLA crystals but did not lead to a more compact chain packing of the crystal lattice in PLLA composites than in pure PLLA. The equilibrium melting temperature (T) obtained from Hoffman‐Weeks plots were found to increase with increasing CNT‐g‐PLLA content. Small angle X‐ray scattering data revealed that thicknesses of crystal layer and amorphous layer of PLLA both decreased with increasing CNT contents. © 2009 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 48: 145–152, 2010 相似文献
103.
Jiun‐Yang Chang Mohamed H. Abd El‐Razek Yu‐Hui Chen Yuan‐Bin Cheng Shun‐Ying Chen Ching‐Te Chien Yao‐Haur Kuo Ya‐Ching Shen 《Helvetica chimica acta》2010,93(1):123-132
A phytochemical investigation of the MeOH extract of Illicium arborescens yielded the two new phytoquinoid epimers, 2,3‐didehydro‐5‐O‐methyl‐11‐epiillifunone E ( 1 ) and 2,3‐didehydro‐5‐O‐methylillifunone E ( 2 ), as well as five new sesquiterpene lactones (8,9‐secoprezizaane‐type sesquiterpenes). Two of them, i.e., 3 and 4 , were minwanensin‐type sesquiterpenes, the other two, i.e., 5 and 6 , had the anisatin‐type (or floridanolide type) skeleton, and the fifth, i.e., 7 , was a dunnianin‐type sesquiterpene. Their structures were established by analyses of 1D‐ and 2D‐NMR, HR‐MS, and chemical evidence. The in vitro cytotoxic activity of compounds 1 – 7 was tested against four human tumor cell lines, including HeLa (cervical epitheloid), WiDr (colon), Daoy (medulloblastoma), and Hep2 (liver carcinoma) human‐tumor cells. 相似文献
104.
Two series of new Schiff bases 2 (n=8, 12, 16) derived from (3-hydroxypropyl imino)propan-1, 2-diol with a hydroxyl group at C19/C20-position and their palladium complexes 1 were prepared and their mesomorphic properties investigated by DSC, POM, and XRD. The presence of both hydroxyl groups was found to be crucial in forming the liquid crystalline behavior. All compounds 2a exhibited smectic A or and C phases, in contrast, all compounds 2b formed hexagonal columnar phases. The formation of mesophases in both compounds 1-2 was probably induced by inter-molecular H-bonds. Single crystallographic data in mesogenic compound 2a (n=8) indicated that a dimeric structure with a better linear or rod-like molecular shape was formed by an inter-molecular H-bond (O4-O1′, ∼1.854 Å). Another inter-molecular H-bond (∼1.903 Å) between two dimeric structures was also observed. It crystallizes in a monoclinic space group P2(1)/c. On the other hand, all palladium complexes 1 formed enantiotropic smectic A phases. Single crystallographic data in mesogenic compound 1a (n=8) indicated that the geometry at Pd2+ center was coordinated as slightly twisted square planar. It crystallizes in a monoclinic space group P2(1)/n. An inter-molecular H-bond (∼1.799 Å) between neighboring molecules were observed, which might have facilitated the formation of mesophases. Variable-temperature powder XRD experiments confirmed their mesophase structures. 相似文献
105.
Chih-Ching Chien Chian-Chiao Hong Po-Chi Soo Yu-Hong Wei Shan-Yu Chen Mei-Ling Cheng Yi-Ming Sun 《Applied biochemistry and biotechnology》2010,162(8):2355-2364
Polyhydroxyalkanoates are polyesters synthesized by numerous microorganisms. These polyesters are biodegradable and have similar
properties to those of conventional plastics. Cupriavidus taiwanensis strain 184 is phylogenetically related to the well-known polyhydroxybutyrate (PHB) producer Ralstonia eutropha (Cupriavidus necator) and is also shown to be able to accumulate significant amounts of PHB. In this study, we cloned the PHB synthesis genes
(phaCAB) from C. taiwanensis 184 into Escherichia coli for biosynthesis of PHB. The recombinant E. coli strains were able to synthesize significant amounts of PHB. The PHB amounted to about 66∼70% of total cell material of these
recombinant strains. 相似文献
106.
Biechele TL Camp ND Fass DM Kulikauskas RM Robin NC White BD Taraska CM Moore EC Muster J Karmacharya R Haggarty SJ Chien AJ Moon RT 《Chemistry & biology》2010,17(11):1177-1182
To identify new protein and pharmacological regulators of Wnt/β-catenin signaling, we used a cell-based reporter assay to screen a collection of 1857 human-experienced compounds for their ability to enhance activation of the β-catenin reporter by a low concentration of WNT3A. This identified 44 unique compounds, including the FDA-approved drug riluzole, which is presently in clinical trials for treating melanoma. We found that treating melanoma cells with riluzole in?vitro enhances the ability of WNT3A to regulate gene expression, to promote pigmentation, and to decrease cell proliferation. Furthermore riluzole, like WNT3A, decreases metastases in a mouse melanoma model. Interestingly, siRNAs targeting the metabotropic glutamate receptor, GRM1, a reported indirect target of riluzole, enhance β-catenin signaling. The unexpected regulation of β-catenin signaling by both riluzole and GRM1 has implications for the future uses of this drug. 相似文献
107.
Masilamani Jeganmohan Dr. Sivakolundu Bhuvaneswari Dr. Chien‐Hong Cheng Prof. Dr. 《化学:亚洲杂志》2010,5(1):153-159
The reaction of benzynes with N‐heteroaromatics including quinolines, isoquinolines, and pyridines and various terminal alkynes or ketones with an α‐hydrogen in the presence of KF and 18‐crown‐6 in THF at room temperature for 8 h gave various N‐arylated 1,2‐dihydroheteroaromatics in good to moderate yields. Some of these product structures are found in various naturally occurring and biologically active heterocyclic compounds. The reaction involves an unusual multiple construction of new C? C, C? N, and C? H bonds and the cleavage of a C? H bond in one pot. It is likely that the three‐component coupling proceeds through the nucleophilic addition of quinoline to benzyne, which generates a zwitterionic species. The latter then attracts a proton from terminal alkyne (or ketone) to generate an N‐arylated quinolinium cation and an acetylide anion. Further reaction of these two ions provides the final substituted 1,2‐dihydroquinolines. In the reaction, the terminal alkyne acts first as a proton donor and then as a nucleophile. The application of a three‐component coupling reaction product, 1,2‐dihydro‐2‐pyridinyl alkyne in a stereospecific [4+2] Diels–Alder cycloaddition reaction with N‐phenyl maleimide to give an isoquinuclidine derivative, an important core present in various natural products, is demonstrated. 相似文献
108.
Yu CC Chen HW Chen MJ Chang YC Chien SC Kuo YH Yang FL Wu SH Chen J Yu HH Chao LK 《Natural product communications》2010,5(12):1941-1944
The present study investigated the chemical composition of Isochrysis galbana Parke, a marine microalga which is widely used as a feedstock in aquaculture. From gas chromatography/mass spectrometric analysis the mono-sugar compositions of I. galbana were 2.1% fucose, 2.5% rhamnose, 2.7% arabinose, 8.5% xylose, 15.7% mannose, 32.7% galactose and 35.8% glucose. The polysaccharides of I. galbana were able to induce prointerleukin-1beta (pro-IL-1beta) protein expression within murine macrophages. Furthermore, five kinds of chlorophyll and one sterol were separated from the ethanolic extracts, including pheophorbide-a, ethyl pheophorbide-a, 10S-10-hydroxypheophytin-a, 10R-10-hydroxypheophytin-a, (132-R)-pheophytin-a, and brassicasterol. In addition, the major soluble components of the ethanol/n-hexane extract were 9-octadecenoic acid (E) (38.4%), hexadecanoic acid (23.3%), tetradecanoic acid (15.7%), and octadecanoic acid (7.2%), but only a few polyunsaturated fatty acids were found, such as 9,12,15-octadecatrienoic acid (1.9%), 9,12-octadecadienoic acid (Z,Z) (3.4%), and docosahexaenoic acid (0.2%). This is the first occasion that polysaccharides from I. galbana have been demonstrated to exert immunomodulatory properties by the induction of IL-1 within macrophages. 相似文献
109.
110.
Félix R Vázquez-Chona Alex Swan W Drew Ferrell Li Jiang Wolfgang Baehr Wei-Ming Chien Matthew Fero Robert E Marc Edward M Levine 《BMC neuroscience》2011,12(1):1-11