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211.
QuBiLS‐MIDAS: A parallel free‐software for molecular descriptors computation based on multilinear algebraic maps 下载免费PDF全文
212.
Aqueous room temperature metal-catalyzed living radical polymerization of vinyl chloride 总被引:1,自引:0,他引:1
Percec V Popov AV Ramirez-Castillo E Monteiro M Barboiu B Weichold O Asandei AD Mitchell CM 《Journal of the American Chemical Society》2002,124(18):4940-4941
This paper describes the room-temperature living radical polymerization (LRP) of vinyl chloride in H2O/THF in the presence of Cu0 or CuI salts as catalysts, tren or PEI as ligands, and iodoform as initiator. The disproportionation reaction 2CuI + L --> Cu0 + CuII(L) is the crucial step, as it continuously provides the active species for both the initiation (Cu0) and the reversible termination step (CuII). Mn was found to increase linearly with conversion and is in good agreement with Mth, with the Mw/Mn being approximately 1.5. 相似文献
213.
Trivinho-Strixino F Pereira EC Mello SV Oliveira ON 《Langmuir : the ACS journal of surfaces and colloids》2004,20(9):3740-3745
Nanostructured films from two conducting polymers, poly(o-methoxyaniline) (POMA) and poly(3-thiopheneacetic acid) (PTAA), were fabricated with the layer-by-layer (LBL) technique. The electrochemical response of the LBL films differs from that of a POMA cast film, even in a potential range where PTAA is inactive. This is attributed to differences in the diffusion-controlled charge and mass transport, where distinct ionic species participate in the LBL films, as demonstrated by quartz crystal microbalance measurements. The results show that the transport properties of conducting polymers can be changed by alternation with layers of appropriate materials in LBL films. 相似文献
214.
Sotelo E Fraiz N Yáñez M Laguna R Cano E Raviña E 《Chemical & pharmaceutical bulletin》2002,50(12):1574-1577
This paper describes the synthesis and the antiplatelet activity of a series of 4,5-disubstituted-6-phenyl-3(2H)-pyridazinones. Some of these compounds show a dose-dependent activity and were found to be more active than their 5-substituted analogues. 相似文献
215.
Truzzi DR Ferreira AG da Silva SC Castellano EE Lima FC Franco DW 《Dalton transactions (Cambridge, England : 2003)》2011,40(48):12917-12925
The trans-[Ru(NO)(NH(3))(4)(P(OH)(3))]Cl(3) complex was synthesized by reacting [Ru(H(2)O)(NH(3))(5)](2+) with H(3)PO(3) and characterized by spectroscopic ((31)P-NMR, δ = 68 ppm) and spectrophotometric techniques (λ = 525 nm, ε = 20 L mol(-1) cm(-1); λ = 319 nm, ε = 773 L mol(-1) cm(-1); λ = 241 nm, ε = 1385 L mol(-1) cm(-1); ν(NO(+)) = 1879 cm(-1)). A pK(a) of 0.74 was determined from infrared measurements as a function of pH for the reaction: trans-[Ru(NO)(NH(3))(4)(P(OH)(3))](3+) + H(2)O ? trans-[Ru(NO)(NH(3))(4)(P(O(-))(OH)(2))](2+) + H(3)O(+). According to (31)P-NMR, IR, UV-vis, cyclic voltammetry and ab initio calculation data, upon deprotonation, trans-[Ru(NO)(NH(3))(4)(P(OH)(3))](3+) yields the O-bonded linkage isomer trans- [Ru(NO)(NH(3))(4)(OP(OH)(2))](2+), then the trans-[Ru(NO)(NH(3))(4)(OP(H)(OH)(2))](3+) decays to give the final products H(3)PO(3) and trans-[Ru(NO)(NH(3))(4)(H(2)O)](3+). The dissociation of phosphorous acid from the [Ru(NO)(NH(3))(4)](3+) moiety is pH dependent (k(obs) = 2.1 × 10(-4) s(-1) at pH 3.0, 25 °C). 相似文献
216.
Campuzano S Pedrero M García JL García E García P Pingarrón JM 《Analytical and bioanalytical chemistry》2011,399(7):2413-2420
A disposable magnetogenosensor for the rapid, specific and sensitive detection of Streptococcus pneumoniae is reported. The developed procedure involves the use of streptavidin-modified magnetic beads, a specific biotinylated capture
probe that hybridizes with a specific region of lytA, the gene encoding the pneumococcal major autolysin, and appropriate primers for asymmetric polymerase chain reaction (PCR)
amplification. Capture probes and amplicons specific for S. pneumoniae were selected by a careful analysis of all lytA alleles available. The selected primers amplify a 235-bp fragment of pneumococcal lytA. A detection limit (LOD) of 5.1 nM was obtained for a 20-mer synthetic target DNA without any amplification protocol, while
the LOD for the asymmetric PCR amplicon was 1.1 nM. A RSD value of 6.9% was obtained for measurements carried out with seven
different genosensors for 1.1-nM aPCR product. The strict specificity of the designed primers was demonstrated by aPCR amplification
of genomic DNA prepared from different bacteria, including some closely related streptococci. Direct asymmetric PCR (daPCR),
using cells directly from broth cultures of S. pneumoniae, showed that daPCR products could be prepared with as few as 2 colony-forming units (CFU). Furthermore, this methodology
did not show any cross-reaction with closely related streptococci such as Streptococcus mitis (or Streptococcus pseudopneumoniae) even when present in the culture at concentrations up to 105 times higher than that of S. pneumoniae. Preliminary data for rapid detection of pneumococcus directly in clinical samples has shown that it is possible to discriminate
between non-inoculated blood and urine samples and samples inoculated with only 103 CFU mL−1
S. pneumoniae. 相似文献
217.
A new extension of the generalized topological indices (GTI) approach is carried out to represent “simple” and “composite”
topological indices (TIs) in an unified way. This approach defines a GTI-space from which both simple and composite TIs represent
particular subspaces. Accordingly, simple TIs such as Wiener, Balaban, Zagreb, Harary and Randić connectivity indices are
expressed by means of the same GTI representation introduced for composite TIs such as hyper-Wiener, molecular topological
index (MTI), Gutman index and reverse MTI. Using GTI-space approach we easily identify mathematical relations between some
composite and simple indices, such as the relationship between hyper-Wiener and Wiener index and the relation between MTI
and first Zagreb index. The relation of the GTI-space with the sub-structural cluster expansion of property/activity is also
analysed and some routes for the applications of this approach to QSPR/QSAR are also given. 相似文献
218.
Maria Letizia Ciavatta M. Pilar Lopez-Gresa Rosario Nicoletti Ernesto Mollo Guido Cimino 《Tetrahedron》2008,64(22):5365-5369
Chemical investigation of the culture broth of the fungus Eutypella scoparia ICB-OBX, isolated from the marine pulmonate mollusc Onchidium sp., led to the finding of novel compounds 1 and 2, structurally related to angiotensin II binding inhibitors cytosporins, along with unrelated known nitrogen metabolites (compounds 3-5). The structure and the relative stereochemistry of the novel metabolites were assigned mainly by a detailed analysis of two-dimensional NMR techniques whereas the absolute stereochemistry was proposed by modified Mosher's method. Compound 2 contains an unusual cyclic carbonate functionality that is rare among natural products. 相似文献
219.
220.
Barile E Borriello M Di Pietro A Doreau A Fattorusso C Fattorusso E Lanzotti V 《Organic & biomolecular chemistry》2008,6(10):1756-1762
A new series of diterpenes, the jatrophanes euphoscopin M (1), euphoscopin N (2) and euphornin L (3), and the lathyrane euphohelioscopin C (7) were isolated from plants of Euphorbia helioscopia L., together with four other known analogues, euphoscopin C (4), euphornin (5), epieuphoscopin B (6) and euphohelioscopin A (8). The new compound stereostructures were elucidated by NMR analysis and computational data. The resulting isolated diterpenes were found to be potent inhibitors of P-glycoprotein (ABCB1), while showing an absence of significant activity against BCRP (ABCG2), despite the high substrate overlapping of these transporters, thus including them in the third-generation class of specific multidrug transporter modulators. 相似文献