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91.
92.
Kassoum Barry Gisèle Laure Lecomte-Nana Mohamed Seynou Michael Faucher Philippe Blanchart Claire Peyratout 《International Journal of Applied Ceramic Technology》2022,19(6):3084-3098
Silicate ceramics were shaped using tape casting (TC) and freeze tape casting (FTC) processes from three clays labeled HCR, KORS, and KCR. These clays exhibited mass content of 77% halloysite–10 Å, 29% kaolinite, and 98% kaolinite minerals, respectively. After casting the slurries, the dried tapes were sintered at 1200°C. The microstructure changes were characterized before and after sintering using scanning electron microscopy. The apparent porosity of TC samples was lower (36–47 vol.%) compared to values obtained with FTC samples (67–79 vol.%). The latter samples exhibited a highly textured porosity, with micron-sized pores aligned perpendicular to the tape surfaces. Upon sintering, the porosity of TC samples tended to decrease conversely to the case of FTC samples. Such behavior seemed related to the simultaneous effect of organic additives and ice templating. Consequently, the FTC samples showed a relatively low mechanical strength of 3–7 MPa and thermal conductivity of .14– .22 W m−1 K−1. After sintering, the mullite crystallization contributed to strengthen the bulk materials, helping to compensate for the detrimental effect of porosity on the stress to rupture and on thermal conductivity values. 相似文献
93.
94.
Irene J. A. Baker Barry Matthews Hector Suares Irena Krodkiewska D. Neil Furlong Franz Grieser Calum I. Drummond 《Journal of surfactants and detergents》2000,3(1):1-11
Ultimate aerobic biodegradabilities of an array of sugar ester surfactants were determined by International Standards Organisation
method 7827, “Water Quality—Evaluation in an Aqueous Medium of the Aerobic Biodegradability of Organic Compounds, Method by
Dissolved Organic Carbon” (1984). The surfactants were nonionic sugar esters with different-sized sugar head groups (formed
from glucose, sucrose, or raffinose) and different lengths and numbers of alkyl chains [formed from lauric (C12) or palmitic (C16) acid]. Analogous anionic sugar ester surfactants, formed by attaching an α-sulfonyl group adjacent to the ester bond, and
sugar esters with α-alkyl substituents were also studied. It was found that variations in sugar head group size or in alkyl
chain length and number do not significantly affect biodegradability. In contrast, the biodegradation rate of sugar esters
with α-sulfonyl or α-alkyl groups, although sufficient for them to be classified as readily biodegradable, was dramatically
reduced compared to that of the unsubstituted sugar esters. An understanding of the relationship between structure and biodegradability
provided by the results of this study will aid the targeted design of readily biodegradable sugar ester surfactants for use
in consumer products. 相似文献
95.
The effect of heartwood extracts from Acacia mangium (heartrot-susceptible) and A. auriculiformis (heartrot-resistant) was examined on the growth of wood rotting fungi with in vitro assays. A. auriculiformis heartwood extracts had higher antifungal activity than A. mangium. The compounds 3,4,7,8-tetrahydroxyflavanone and teracacidin (the most abundant flavonoids in both species) showed antifungal activity. A. auriculiformis contained higher levels of these flavonoids (3.5- and 43-fold higher, respectively) than A. mangium. This suggests that higher levels of these compounds may contribute to heartrot resistance. Furthermore, both flavonoids had strong 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity and laccase inhibition. This suggests that the antifungal mechanism of these compounds may involve inhibition of fungal growth by quenching of free radicals produced by the extracellular fungal enzyme laccase. 相似文献
96.
The effect of unsaturated fatty acids on the abundance of Δ6 desaturase (D6D) mRNA and the fatty acid composition of HepG2
cell membranes was examined. Supplementation of HepG2 cells with oleic acid (18:1n-9, OA), linoleic acid (18:2n-6, LA), α-linolenic
acid (18:3n-3, ALA), arachidonic acid (20:4n-6, AA) or eicosapentaenoic acid (20:5n-3, EPA) reduced D6D mRNA abundance by
39 ± 6.6, 40 ± 2.2, 31 ± 5.2, 55 ± 4.8, and 52 ± 5.0%, respectively, compared with control cells. Despite the reduction in
D6D mRNA abundance, the level of D6D conversion products (20:3n-9, EPA and AA) in OA, ALA and LA supplemented cells, respectively,
was elevated above that in control cells. Our results suggest that although unsaturated fatty acids decrease the abundance
of D6D mRNA by as much as 50%, the conversion of polyunsaturated fatty acids and accumulation of long chain polyunsaturated
fatty acids (LCPUFA) in HepG2 cell phospholipids continues to occur. 相似文献
97.
Bubert C Woo LW Sutcliffe OB Mahon MF Chander SK Purohit A Reed MJ Potter BV 《ChemMedChem》2008,3(11):1708-1730
4-(((4-Cyanophenyl)(4H-1,2,4-triazol-4-yl)amino)methyl)phenyl sulfamate (6 a) was the first dual aromatase-sulfatase inhibitor (DASI) reported. Several series of its derivatives with various linker systems between the steroid sulfatase (STS) and the aromatase inhibitory pharmacophores were synthesised and evaluated in JEG-3 cells. The X-ray crystal structures of the aromatase inhibitors, DASI precursors 42 d and 60, and DASI 43 h were determined. Nearly all derivatives show improved in vitro aromatase inhibition over 6 a but decreased STS inhibition. The best aromatase inhibitor is 42 e (IC(50)=0.26 nM) and the best DASI is 43 e (IC(50 aromatase)=0.45 nM, IC(50 STS)=1200 nM). SAR for aromatase inhibition shows that compounds containing an alkylene- and thioether-based linker system are more potent than those that are ether-, sulfone-, or sulfonamide-based, and that the length of the linker has a limited effect on aromatase inhibition beyond two methylene units. Compounds 43 d-f were studied in vivo (10 mg kg(-1), single, p.o.). The most potent DASI is 43 e, which inhibited PMSG-induced plasma estradiol levels by 92 % and liver STS activity by 98 % 3 h after dosing. These results further strengthen the concept of designing and developing DASIs for potential treatment of hormone-related cancers. 相似文献
98.
Oishi S Masuda R Evans B Ueda S Goto Y Ohno H Hirasawa A Tsujimoto G Wang Z Peiper SC Naito T Kodama E Matsuoka M Fujii N 《Chembiochem : a European journal of chemical biology》2008,9(7):1154-1158
The design, synthesis, and bioevaluation of fluorescence- and biotin-labeled CXCR4 antagonists are described. The modification of D-Lys8 at an epsilon-amino group in the peptide antagonist Ac-TZ14011 derived from polyphemusin II had no significant influence on the potent binding of the peptide to the CXCR4 receptor. The application of the labeled peptides in flow cytometry and confocal microscopy studies demonstrated the selectivity of their binding to the CXCR4 receptor, but not to CXCR7, which was recently reported to be another receptor for stromal cell-derived factor 1 (SDF-1)/CXCL12. 相似文献
99.
The synthesis and in vitro biological evaluation (JEG-3 cells) of a series of novel and potent aromatase inhibitors, prepared by microwave-enhanced Suzuki cross-coupling methodology, are reported. These compounds possess a biphenyl template incorporated with the haem-ligating triazolylmethyl moiety, either on its own or in combination with other substituent(s) at various positions on the phenyl rings. The most potent aromatase inhibitor reported herein has an IC(50) value of 0.12 nM, although seven of its congeners are also highly potent (IC(50)相似文献
100.
Ni-Al2 O3 composites containing 5 to 80 vol% Ni were produced using powder processing methods and their thermal expansion behavior was studied using dilatometry. By varying composition and relative particle sizes, either interpenetrating-phase or particle-reinforced microstructures were obtained. Experimentally determined values of the mean thermal expansion coefficient were compared with predictions made using two different rule-of-mixtures (ROM) formulations. Experimental results for interpenetrating-phase composites were in reasonable agreement with linear ROM estimates. Certain particle-reinforced microstructures that contain processing-induced damage did not correlate as well with ROM predictions. By accounting for this damage in ROM models, better agreement with experimental observations was obtained. However, linear ROM predictions were reasonable over the entire composition range. 相似文献