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11.
Brigita Tomšič Barbara Simončič Boris Orel Lidija Černe Petra Forte Tavčer Mateja Zorko Ivan Jerman Aljaž Vilčnik Janez Kovač 《Journal of Sol-Gel Science and Technology》2008,47(1):44-57
Multifunctional, water and oil repellent and antimicrobial finishes for cotton fibres were prepared from a commercially available
fluoroalkylfunctional water-born siloxane (FAS) (Degussa), nanosized silver (Ag) (CHT) and a reactive organic–inorganic binder
(RB) (CHT). Two different application procedures were used: firstly, one stage treatment of cotton fabric samples by FAS sol
(i), as well as by a sol mixture constituted from all three precursors (Ag–RB–FAS, procedure 1S) (ii), and secondly, two stage
treatment of cotton by Ag–RB sol and than by FAS sol (Ag–RB + FAS, procedure 2S) (iii). The hydrophobic and oleophobic properties
of cotton fabrics treated by procedures (i)–(iii) before and after consecutive (up to 10) washings were established from contact
angle measurements (water, diiodomethane and n-hexadecane) and correlated with infrared and XPS spectroscopic measurements. The results revealed that even after 10 washing
cycles cotton treated with Ag–RB + FAS (2S) retained an oleophobicity similar to that of the FAS treated cotton, while the
Ag–RB–FAS (1S) cotton fibres exhibited a loss of oleophobicity already after the second washing, even though fluorine and
C–F vibrational bands were detected in the corresponding XPS and IR spectra. The antibacterial activity of cotton treated
by procedures (i)–(iii) was tested by its reduction of the bacteria Escherichia coli and Staphylococcus aureus following the AATCC 100-1999 standard method and EN ISO 20743:2007 transfer method. The reduction in growth of both bacteria
was nearly complete for the unwashed Ag–RB and Ag–RB–FAS (S1), but for the unwashed Ag–RB + FAS (S2) treated cotton no reduction
of S. aureus and 43.5 ± 6.9% reduction of E. coli was noted. After the first washing, the latter two finishes exhibited nearly a complete reduction of E. coli but for the Ag–RB treated cotton the reduction dropped to 88.9 ± 3.4. None of the finishes retained antibacterial properties
after 10 repetitive washings. The beneficial and long-lasting low surface energy effect of FAS finishes in the absence of
Ag nanoparticles, which led to the “passive” antibacterial properties of FAS treated cotton fabrics, was established by applying
the EN ISO 20743:2007 transfer method. The results revealed a reduction in bacteria of about 21.9 ± 5.7% (FAS), 13.1 ± 4.8%
(Ag–RB–FAS (S1)) and 41.5 ± 3.7% (Ag–Rb + FAS (S2)), while no reduction of the growth of bacteria was observed for cotton
treated with Ag nanoparticles after 10 repetitive washings. The physical properties (bending rigidity, breaking strength,
air permeability) of finished cotton samples were determined, and showed increased fabric softness and flexibility as compared
to the Ag–RB treated cotton, but a slight decrease of breaking strength in the warp and weft directions, while air permeability
decreased for all type of finishes. 相似文献
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Ae. de Groot M.P. Broekhuysen L.L. Doddema M.C. Vollering J.M.M. Westerbeek 《Tetrahedron letters》1982,23(46):4831-4834
The total synthesis of (±)-colorata-4(13),8-dienolide (), a sesquiterpene with a rearranged drimane skieleton, is described using 6β, 8aβ-dimethyl-5-methylene-3,4,4aα, 5,6,7,8,8a-octahydro-1(2H)-naphtalenone () as a key intermediate. A new annelation method for butenolides via hydrolysis of a thiohenyl furan is reported. 相似文献
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Ukmar T Godec A Planinšek O Kaučič V Mali G Gaberšček M 《Physical chemistry chemical physics : PCCP》2011,13(35):16046-16054
Compounds embedded into mesoporous or even microporous matrices are interesting for many emerging applications, such as novel catalysts, sensors, batteries, hydrogen storage materials or modern drug delivery devices. We report on two unexpected phenomena regarding the structural and dynamic properties of a model drug substance (indomethacin) when confined in mesoscopic matrices. Firstly, we show that the confinement directs the crystallization of the drug into a stable polymorph that is not otherwise formed at all; its relative amount depends on the pore size. This phenomenon is also explained theoretically using a modified classical heterogeneous nucleation theory. Secondly, we demonstrate that--even at relatively low volume fractions--the confined drug forms a condensed phase in a way that obstructs the passage of the pore channels. This may have far-reaching consequences for understanding the mechanisms of drug release from porous matrices. 相似文献
16.
Aljaž Zalar 《Integral Equations and Operator Theory》2014,79(2):219-242
Regular normalized W-valued spectral measures on a compact Hausdorff space X are in one-to-one correspondence with unital *-representations ${\rho : C(X, \mathbb{C}) \to W}$ , where W stands for a von Neumann algebra. In this paper we show that for every compact Hausdorff space X and every von Neumann algebras W 1, W 2 there is a one-to-one correspondence between unital *-representations ${\rho : C(X, W_1) \to W_2}$ and special B(W 1, W 2)-valued measures on X that we call non-negative spectral measures. Such measures are special cases of non-negative measures that we introduced in our previous paper (Cimpri? and Zalar, J Math Anal Appl 401:307–316, 2013) in connection with moment problems for operator polynomials. 相似文献