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171.
D Dascier E Ji A Parthasarathy KS Schanze DG Whitten 《Langmuir : the ACS journal of surfaces and colloids》2012,28(31):11286-11290
Cationic end-only-functionalized oligo(arylene-ethynylene)s (EO-OPEs) have recently been found to be broad-spectrum and effective antimicrobial agents because of their unique structure and optical properties. In this study, we investigated their potential use for preventing and reducing Escherichia coli (E. coli) biofilms. The Calgary biofilm device (CBD) was used to form bacterial biofilms of E. coli; in these studies, the minimum inhibitory concentration (MIC) and the minimum biofilm eradication concentration (MBEC) were determined. E. coli biofilms uniformly grow on pegs of the CBD device lid. The MIC values determined for EO-OPEs are comparable to those found for standard antibiotics such as kanamycin (MIC = 11.2 μg/mL). About 10-30 times the concentration of EO-OPEs was required to eradicate E. coli biofilms and prevent regrowth in the dark. Near-UV irradiation of EO-OPEs enhanced their efficacy in killing biofilms. 相似文献
172.
Ridgers CP Brady CS Duclous R Kirk JG Bennett K Arber TD Robinson AP Bell AR 《Physical review letters》2012,108(16):165006
In simulations of a 10 PW laser striking a solid, we demonstrate the possibility of producing a pure electron-positron plasma by the same processes as those thought to operate in high-energy astrophysical environments. A maximum positron density of 10(26) m(-3) can be achieved, 7 orders of magnitude greater than achieved in previous experiments. Additionally, 35% of the laser energy is converted to a burst of γ rays of intensity 10(22) W cm(-2), potentially the most intense γ-ray source available in the laboratory. This absorption results in a strong feedback between both pair and γ-ray production and classical plasma physics in the new "QED-plasma" regime. 相似文献
173.
The shear flow behaviour of stirred yoghurt in the cone-and-plate and cylindrical Couette geometries was studied using diffusing
wave spectroscopy (DWS) and nuclear magnetic resonance (NMR) velocimetry. Differences between the transmission and backscattering
DWS correlations suggest the formation of a high shear rate band near the surface of a moving cone of a cone-and-plate geometry
at low shear rates. At higher shear rates, homogeneous shear flow is indicated. NMR velocimetry unambiguously demonstrated
that a high shear rate band forms at the moving inner wall of a cylindrical Couette geometry at low shear rates. At intermediate
shear rate, a high shear rate band is formed at the stationary outer wall and plug-like flow is observed mid-gap. At higher
shear rates, homogeneous shear flow is observed. Slip is seen at both walls. The three flow regimes appear to correlate loosely
with transitions in the pseudo-steady-state flow curve and may reflect a break-up of the protein aggregates observed with
confocal microscopy. 相似文献
174.
The strain-controlled flow of a wormlike micellar solution in cylindrical Couette geometries with smooth and rough glass inner
walls is investigated using 2D 1H NMR velocimetry. We find anomalous shear banding in which fluctuating slip dynamics in combination with surfactant properties
lead to a non-lever rule behaviour where the interface position remains constant while the high and low shear rates change.
Velocities in the flow direction are imaged in the flow-gradient/vorticity plane. The spatiotemporal resolution achieved reveals
fluctuations in flow structure along the vorticity axis and instability of the high shear band. 相似文献
175.
Kirk Olson Yiyan Chen Gregory L. Baker 《Journal of polymer science. Part A, Polymer chemistry》2001,39(16):2731-2739
Cyclodextrins thread onto polymer chains to form inclusion complexes, especially when the polymer is hydrophobic relative to the solvent. Selective threading might occur when the polymer architecture contains both hydrophobic and hydrophilic segments. α‐Cyclodextrin formed crystalline inclusion complexes with (AB)n microblock copolymers, where the A block was a linear alkyl segment containing a single double bond and the B block was an exact length segment of poly(ethylene oxide). The complexes were isolated and characterized by solution and solid‐state NMR, X‐ray diffraction, differential scanning calorimetry, and thermogravimetric analysis. Each method confirmed complex formation and showed that the physical properties of the complexes were distinct from those of its individual components. The X‐ray data were consistent with known inclusion complexes having a channel or column crystal structure. The stoichiometry of the complex formation, 2.3 α‐cyclodextrin rings per polymer repeat unit, was determined by NMR analysis of the complexes and from an analysis of the inclusion complex yields. The data suggest that the inclusion complex stoichiometry is defined by the increasing insolubility of the polymer–cyclodextrin complex. Solid‐state NMR data were consistent with a preference for threading onto hydrophobic segments of the (AB)n polymer. © 2001 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 39: 2731–2739, 2001 相似文献
176.
纳米阵列电极研究* 总被引:1,自引:0,他引:1
纳米阵列电极作为一种人工组装的纳米结构体系,具有高传质速率、低双电层充电电流、小时间常数、小IR降及高信噪比、可操作性强和测量灵敏度高等优势,因而在电化学理论研究、生物传感器、电催化材料和高能化学电源电极材料等方面等具有广阔的应用前景。迄今为止,人们采用多种材料设计制备出包括圆盘状、圆柱形、球形、圆锥形、叉指状和井状等各种形状的纳米阵列电极。其制作方法主要包括模板法、刻蚀法和自组装法等,电极的表征主要采用电子显微镜技术和电化学方法。本文结合我们的工作和国内外文献,就纳米阵列电极制作方法、表征和应用等方面进行了评述,并对目前纳米阵列电极研究中存在的问题及发展前景进行了探讨和展望。 相似文献
177.
T. A. Armstrong R. P. Barnes M. Benayoun W. Beusch I. J. Bloodworth J. N. Carney D. Di Bari C. J. Dodenhoff D. Evans B. R. French B. Ghidini M. Girone A. Jacholkowski J. B. Kinson A. Kirk K. Knudson V. Lenti V. Manzari F. Navach A. Palano E. Quercigh M. Sené R. Sené G. Vassiliadis O. Villalobos Baillie M. F. Votruba 《Zeitschrift fur Physik C Particles and Fields》1991,52(3):389-395
The reactionpp→p f (ηπ+π?)p s where the ηπ+π? system is centrally produced has been studied at 300 GeV/c incident momentum at the CERN Ω spectrometer. The ηπ± mass spectrum shows a strong δ/a 0(980) signal having a mass of 984±4 and Γ=95±14 MeV. The ηπ+π? mass spectrum shows η′ andf 1(1285) signals over little background. A spin-parity analysis of the ηπ+π? system shows evidence for aJ PC =1++ peak at thef 1(1285) mass but no evidence for the pseudoscalar states η(1270) andl/η(1440). No evidence is found for the ηππ decay of theE/f 1(1420) meson for which we set an upper limit BR(E/f 1(1420)→ηππ)<0.1 at 95% cl. 相似文献
178.
179.
-lyxose has been elaborated to methyl deoxypseudomonate B (I) by a sequence of reactions involving the Lewis acid catalyzed anomeric allylation procedure and a stereospecific Grignard addition reaction. 相似文献
180.