排序方式: 共有43条查询结果,搜索用时 15 毫秒
11.
A natural carbon from coconut fiber is used as a main composite material of gas diffusion layer (GDL) for fuel cell electrode. The composite comprise of polymer (ethylene vinyl acetate and poly ethylene glycol) and carbon in various compositions. The materials are mixed in xylene and printed using casting method. The composite is coated with polytetrafluoro ethylene (PTFE) to achieve hydrophobic requirement as GDL. The electrical properties of composite were measured by using LCR-meter, the porosity was obtained by immersion method, and the hydrophobic properties were observed by measuring its contact angle. The results show the electrical conductivity of GDL prepared corresponds to its carbon content. The electrical conductivity of GDLs is 22.17, 26.89, 35, 43, and 52 S/m for the carbon composition of 65, 70, 75, 80, and 85 %, respectively. The composite of 80 % carbon content and coated with PTFE contains 74 % porosity and has desired hydrophobic properties revealed from its high contact angle, i.e., 120°. 相似文献
12.
Saumen Hajra Ananta Karmakar Aswini Kumar Giri Sunit Hazra 《Tetrahedron letters》2008,49(22):3625-3627
(+)- and (−)-Methylenolactocins and phaseolinic acids are synthesized in four steps via asymmetric syn- and anti-aldol reactions of chiral N-succinyl-2-oxazolidinones using the same set of reagents. 相似文献
13.
R. Grigg L.D. Basanagoudar D.A. Kennedy J.F. Malone S. Thianpatanagul 《Tetrahedron letters》1982,23(27):2803-2806
Thioiminoethers and thioiminocarbonates of α-amino acid esters undergo acetic acid catalysed cycloaddition reaction with N-phenylmaleimide via their 1,3-dipolar tautomers. 相似文献
14.
Polymethyl methacrylate has been obtained at 40° with a VOCl3-AlEt3 catalyst in the presence of various amounts of basic additives, at a ratio of 1·5 of Al/V. The configuration of the polymers was affected by the presence of additives. An increase in the percentage of syndiotacticity and no alteration of the stereoblock structure were indicated by i.r. and n.m.r. The effects of additives on the formation of syndiotactic structures are discussed on the basis of their electron donating powers. 相似文献
15.
Waghadkar Yogesh Shinde Manish Ballal Reshma Rane Sunit Gosavi Suresh Chauhan Ratna 《Journal of Solid State Electrochemistry》2017,21(6):1797-1804
Journal of Solid State Electrochemistry - Hierarchically nano-structured ZnO microspheres have been synthesized solvothermally at variable reaction times (6, 12, 36, and 48 h) by using... 相似文献
16.
C-Triazolyl β-d-furanosides 10a–f were synthesized in a stereocontrolled way, starting from d-mannose. In the key steps of the synthesis a diastereoselective reduction of hemiketal 14 and a Cu(I) catalyzed [3+2]-cycloaddition of central building block 18 with various azides were performed. The synthesized hydroxamic acids were tested for their inhibitory activity against LpxC, a Zn2+-dependent deacetylase playing an important role in the biosynthesis of lipid A and therefore representing an interesting target for the development of novel antibiotics against Gram-negative bacteria. The C-triazolyl glycosides 10a–f did not exhibit antibiotic activity. However, the described synthesis is a versatile way to access C-triazolyl β-d-furanosides bearing all of their substituents at the same side of the tetrahydrofuran ring. 相似文献
17.
Design of Monodisperse and Well‐Defined Polypeptide‐Based Polyvalent Inhibitors of Anthrax Toxin 下载免费PDF全文
Sanket Patke Mohan Boggara Ronak Maheshwari Sunit K. Srivastava Manish Arha Marc Douaisi Jacob T. Martin Ian B. Harvey Matthew Brier Tania Rosen Jeremy Mogridge Prof. Ravi S. Kane 《Angewandte Chemie (International ed. in English)》2014,53(31):8037-8040
The design of polyvalent molecules, presenting multiple copies of a specific ligand, represents a promising strategy to inhibit pathogens and toxins. The ability to control independently the valency and the spacing between ligands would be valuable for elucidating structure–activity relationships and for designing potent polyvalent molecules. To that end, we designed monodisperse polypeptide‐based polyvalent inhibitors of anthrax toxin in which multiple copies of an inhibitory toxin‐binding peptide were separated by flexible peptide linkers. By tuning the valency and linker length, we designed polyvalent inhibitors that were over four orders of magnitude more potent than the corresponding monovalent ligands. This strategy for the rational design of monodisperse polyvalent molecules may not only be broadly applicable for the inhibition of toxins and pathogens, but also for controlling the nanoscale organization of cellular receptors to regulate signaling and the fate of stem cells. 相似文献
18.
The 2-formyl 1,3,5,7-tetraaryl aza-BODIPY and 2-formyl-6-bromo 1,3,5,7-tetraaryl aza-BODIPY were subjected to Wittig reaction with three different ylides under simple reaction conditions and afforded the conjugated aza-BODIPYs in high yields. The aza-BODIPYconjugates resulted from 2-formyl-6-bromo aza-BODIPYs were reacted further with 4-anisyl boronic acid under mild Pd(0) coupling conditions and afforded 1,2,3,5,7-pentaaryl aza-BODIPYconjugates. The method works efficiently and allows to introduce different substituents at the aza-BODIPY core. All compounds were characterized by HRMS, 1D, 2D NMR, absorption, fluorescence and electrochemical techniques. The spectral and electrochemical studies indicated that the introduction of conjugated substituents at the aza-BODIPY core alter the electronic properties significantly. 相似文献
19.
Ketthip Suphavanich Phornphimon Maitarad Supa Hannongbua Pichit Sudta Sunit Suksamrarn Yuthana Tantirungrotechai Jumras Limtrakul 《Monatshefte für Chemie / Chemical Monthly》2009,18(8):273-280
Abstract
A new series of xanthone derivatives against the oral human epidermoid carcinoma (KB) cancer cell line is examined to determine the relationship between the structural properties and the biological activity of these compounds—the 3-D quantitative structure–activity relationship (3D-QSAR)—using comparative molecular field analysis (CoMFA) and comparative molecular similarity indices analysis (CoMSIA). The best CoMFA and CoMSIA models were obtained using the atom-based alignment of 33 compounds, 22 training compounds and 11 tested compounds, and these give desirable statistics; those for the CoMFA standard model were: r cv2 = 0.691, r 2 = 0.998, S press = 0.178, s = 0.014 and F = 1080.765, while CoMSIA combined steric, electrostatic, hydrophobic and hydrogen-bond acceptor fields: r cv2 = 0.600, r 2 = 0.988, S press = 0.206, s = 0.034 and F = 284.433. The 3D-QSAR models calculated satisfactory test set activities. The 3D-QSAR contour plots correlated strongly with the experimental data for the binding topology. For this reason, these results would be beneficial for predicting affinities with the compounds of interest, and they are advantageous for guiding the design and synthesis of new and more effective anticancer agents. 相似文献20.
Ketthip Suphavanich Phornphimon Maitarad Supa Hannongbua Pichit Sudta Sunit Suksamrarn Yuthana Tantirungrotechai Jumras Limtrakul 《Monatshefte für Chemie / Chemical Monthly》2009,140(3):273-280
Abstract A new series of xanthone derivatives against the oral human epidermoid carcinoma (KB) cancer cell line is examined to determine
the relationship between the structural properties and the biological activity of these compounds—the 3-D quantitative structure–activity
relationship (3D-QSAR)—using comparative molecular field analysis (CoMFA) and comparative molecular similarity indices analysis
(CoMSIA). The best CoMFA and CoMSIA models were obtained using the atom-based alignment of 33 compounds, 22 training compounds
and 11 tested compounds, and these give desirable statistics; those for the CoMFA standard model were: r
cv2 = 0.691, r
2 = 0.998, S
press = 0.178, s = 0.014 and F = 1080.765, while CoMSIA combined steric, electrostatic, hydrophobic and hydrogen-bond acceptor fields: r
cv2 = 0.600, r
2 = 0.988, S
press = 0.206, s = 0.034 and F = 284.433. The 3D-QSAR models calculated satisfactory test set activities. The 3D-QSAR contour plots correlated strongly
with the experimental data for the binding topology. For this reason, these results would be beneficial for predicting affinities
with the compounds of interest, and they are advantageous for guiding the design and synthesis of new and more effective anticancer
agents.
Graphical abstract
A new and more effective anticancer agent of xanthone derivatives against the oral human epidermoid carcinoma (KB) cell line,
as investigated by CoMFA and CoMSIA analysis 相似文献