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1.
Dressings Loaded with Cyclodextrin–Hamamelitannin Complexes Increase Staphylococcus aureus Susceptibility Toward Antibiotics Both in Single as well as in Mixed Biofilm Communities 下载免费PDF全文
Gilles Brackman Maria José Garcia‐Fernandez Joke Lenoir Laurens De Meyer Jean‐Paul Remon Thomas De Beer Angel Concheiro Carmen Alvarez‐Lorenzo Tom Coenye 《Macromolecular bioscience》2016,16(6):859-869
Bacteria reside within biofilms at the infection site, making them extremely difficult to eradicate with conventional wound care products. Bacteria use quorum sensing (QS) systems to regulate biofilm formation, and QS inhibitors (QSIs) have been proposed as promising antibiofilm agents. Despite this, few antimicrobial therapies that interfere with QS exist. Nontoxic hydroxypropyl‐β‐cyclodextrin‐functionalized cellulose gauzes releasing a burst of the antibiotic vancomycin and the QSI hamamelitannin are developed, followed by a sustained release of both. The gauzes affect QS and biofilm formation of Pseudomonas aeruginosa and Staphylococcus aureus in an in vitro model of chronic wound infection and can be considered as candidates to be used to prevent wound infection as well as treat infected wounds.
2.
Apperloo JJ Groenendaal LB Verheyen H Jayakannan M Janssen RA Dkhissi A Beljonne D Lazzaroni R Brédas JL 《Chemistry (Weinheim an der Bergstrasse, Germany)》2002,8(10):2384-2396
The optical and redox properties of a series of 3,4-ethylenedioxythiophene oligomers (EDOTn, n=1-4) and their beta,beta'-unsubstituted analogues (Tn, n=1-4) are described. Both series are end capped with phenyl groups to prevent irreversible alpha-coupling reactions during oxidative doping. Absorption and fluorescence spectra of both series reveal a significantly higher degree of intrachain conformational order in the EDOTn oligomers. Oxidation potentials (E(PA1) and E(PA2)) determined by cyclic voltammetry reveal that those of EDOTn are significantly lower than the corresponding Tn oligomers as a consequence of the electron-donating 3,4-ethylenedioxy substitution. Linear fits of E(PA1) and E(PA2) versus the reciprocal number of double bonds reveal significantly steeper slopes for the EDOTn than for the Tn oligomers. This could indicate a more effective conjugation for the EDOTn series, confirmed by the fact that coalescence of E(PA1) and E(PA2) is reached already at relatively short chain lengths ( approximately 5 EDOT units) in contrast to the Tn series (>10 thiophene units). The stepwise chemical oxidation of the EDOTn and Tn oligomers in solution was carried out to obtain radical cations and dications. The energies of the optical transitions of the radical cations and dications as determined by UV/Vis/NIR spectroscopy were similar for the two series. These spectroscopic observations are consistent with quantum-chemical calculations performed on the singly charged molecules. Cooling solutions containing T2.+, T3.+, EDOT2.+, and EDOT3.+ revealed the reversible formation of dimers, albeit with a somewhat different tendency, expressed in the values for the dimerization enthalpy. 相似文献
3.
LaSrMnNbO6 has been synthesized by high temperature solid state reaction under 1% H2/Ar dynamic flow. The structure is determined by Rietveld refinement of the powder X-ray diffraction data. It crystallizes in the monoclinic space group P21/n with the unit cell parameters: a=5.69187(12), b=5.74732(10), c=8.07018(15) Å and β=90.0504(29)°, which were also confirmed by electron diffraction. The Mn2+ and Nb5+ ions, whose valence states are confirmed by X-ray absorption near-edge spectroscopy, are almost completely ordered over the B-site (<1% inversion) of the perovskite structure due to the large differences of both cationic size (0.19 Å) and charge. The octahedral framework displays significant tilting distortion according to Glazer’s tilt system a−b−c+. Upon heating, LaSrMnNbO6 decomposes at 690 °C under O2 flow or at 775 °C in air. The magnetic susceptibility data indicate the presence of long-range antiferromagnetic ordering at TN=8 K; the experimentally observed effective paramagnetic moment, μeff=5.76 μB for high spin Mn2+ (3d5, S=5/2) is in good agreement with the calculated value (μcalcd=5.92 μB). 相似文献
4.
A. S. Kalyuzhnaya A. M. Abakumov M. G. Rozova H. D’Hondt J. Hadermann E. V. Antipov 《Russian Chemical Bulletin》2010,59(4):706-711
The complex oxide Ca7Mn2.14Ga5.86O17.93 was synthesized by the solid-state reaction in a sealed evacuated quartz tube at 1000 °C. Its crystal structure was determined
by electron diffraction and X-ray powder diffraction. The structure can be represented as a tetrahedral framework, viz., the
polyanion [(Mn0.285Ga0.715)15O29.86]19- stabilized by the incorporated cation [Ca14GaO6]19+. The polycation consists of the GaO6 octahedra surrounded by the Ca atoms, which are arranged to form a cube capped at all places. The tetrahedral framework is
partially disordered due to the presence of tetrahedra with two possible orientations in the positions (0, 0, 0) and (x, x,
x) with x ≈ 0.15 and 0.17. The relationship between the Ca7Mn2.14Ga5.86O17.93 structures and related ordered phases with the symmetry F23, as well as the influence of the oxygen content on the ordering
in the tetrahedral framework, are discussed. 相似文献
5.
Frederik Detobel Ken Broeckhoven Joke Wellens Bert Wouters Remco Swart Mario Ursem Gert Desmet Sebastiaan Eeltink 《Journal of chromatography. A》2010,1217(18):3085-3090
An experimental study was performed to investigate the effects of column parameters and gradient conditions on the separation of intact proteins using styrene-based monolithic columns. The effect of flow rate on peak width was investigated at constant gradient steepness by normalizing the gradient time for the column hold-up time. When operating the column at a temperature of 60 °C a small C-term effect was observed in a flow rate range of 1–4 μL/min. However, the C-term effect on peak width is not as strong as the decrease in peak width due to increasing flow rate. The peak capacity increased according to the square root of the column length. Decreasing the macropore size of the polymer monolith while maintaining the column length constant, resulted in an increase in peak capacity. A trade-off between peak capacity and total analysis time was made for 50, 100, and 250 mm long monolithic columns and a microparticulate column packed with 5 μm porous silica particles while operating at a flow rate of 2 μL/min. The peak capacity per unit time of the 50 mm long monolithic column with small pore size was superior when the total analysis time is below 120 min, yielding a maximum peak capacity of 380. For more demanding separations the 250 mm long monolith provided the highest peak capacity in the shortest possible time frame. 相似文献
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7.
J. Hadermann 《Physics letters. [Part B]》1975,55(2):141-143
The energy distribution of neutrons following muon capture in heavy nuclei is investigated. It is shown that the experimental high energy tail (E > 10 MeV) of the neutron distribution can be explained by a direct emission process. 相似文献
8.
Chemical Transport of Nickel by Indium Iodide At higher temperatures (1273 → 1073 K) the chemical transport of nickel by means of indium iodide going into the zone with lower temperature is caused by the endothermic reaction Ni + InJ3O,g = NiJ2,g + InJ,g At lower temperatures (873 → 973 K) this reaction is superimposed by the formation of gas complexes. These exothermic reactions cause transport in the inversed direction. 相似文献
9.
Partial fission channel widths can be extracted from fission cross-section analysis only up to a rotation in the space of fission vectors. We propose to obtain a physically significant basis for fission vectors taking into account information from other fission characteristics such as the valley-to-peak ratio of the mass distribution and the number of prompt neutrons emitted per fission event. Fission widths and other channel characteristics are calculated for 0+ resonances in low energy neutron induced fission of 239Pu. 相似文献
10.
A. Wyttenbach P. Baertschi S. Bajo J. Hadermann K. Junker S. Katcoff E.A. Hermes H.S. Pruys 《Nuclear Physics A》1978,294(3):278-292
The probabilities for the reactions (μ?, p), (μ?, pn), (μ?, p2n), (μ?, p3n) and (μ?, α) were measured by activation experiments on 18 elements from Na to Bi. The results suggest the following systematics : (i) the probability W of each type of reaction depends on the atomic number of the target and can be described by W = aexp( -bV), where V is the Coulomb barrier of the compound nucleus for the ejected charged particle; (ii) the factor b is the same for all (μ?, pxn) reactions and not very different for (μ?, α) reactions; (iii) the relative probabilities for (μ?, pxn) reactions for a given target vary as 1 :6 :4 :4 for x = 0, 1, 2, 3. The experimental results are compared with a theoretical estimate of the reaction probability and with the corresponding 14 MeV neutron induced reactions. 相似文献