368 research outputs found

    Superhydrophobic Surface by Replication of Laser Micromachined Pattern in Epoxy/Alumina Nanoparticle Composite

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    Superhydrophobic surfaces were obtained by superposition of microstructure—defined by replication of laser micromachined masters, with nanostructure—created by durable epoxy/γ-Al₂O₃ nanoparticle composite, used for replication. Hierarchical surface topography thus obtained consisted of hexagonally spaced microcavities and nanoparticle agglomerates, exposed on the replica surface by radio frequency (RF) air plasma etching. Surface topography was further enhanced by rims around the microcavity edges, resulting from nanosecond laser micromachining defects in aluminum masters. Subsequent wet chemical hydrophobization with 1H,1H,2H,2H-perfluorotetradecyltriethoxysilane (PFTDTES) provided superhydrophobic behavior in replicas with a microcavity spacing of 30 μm, as indicated by a water contact angle of 160° and a sliding angle of 8°. The preparation method is relatively simple, inexpensive, and potentially scalable.This work was supported by the National Science Centre of Poland through projects nos. 2011/03/N/ST8/05879 and UMO-2012/05/B/ST8/02876. The authors are grateful to Professor Weimin Liu and Professor Feng Zhou of the Lanzhou Institute of Chemical Physics, Chinese Academy of Science, for making the laser micromachining, JEOL SEM, and Drop Shape Analysis equipment available

    The influence of the chain length and the functional group steric accessibility of thiols on the phase transfer efficiency of gold nanoparticles from water to toluene

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    The papers were published with the financial support from the budget of the West Pomeranian Voivodeship.This paper describes the influence of the chain length and the functional group steric accessibility of thiols modifiers on the phase transfer process efficiency of water synthesized gold nanoparticles (AuNPs) to toluene. The following thiols were tested: 1-decanethiol, 1,1-dimethyldecanethiol, 1-dodecanethiol, 1-tetradecanethiol and 1-oktadecanethiol. Nanoparticles (NPs) synthesized in water were precisely characterized before the phase transfer process using Atomic Force Microscopy (AFM) and Transmission Electron Microscopy (TEM). The optical properties of AuNPs before and after the phase transfer were studied by the UV-Vis spectroscopy. Additionally, the particle size and size distribution before and after the phase transfer of nanoparticles were investigated using Dynamic Light Scattering (DLS). It turned out that the modification of NPs surface was not effective in the case of 1,1-dimethyldecanethiol, probably because of the difficult steric accessibility of the thiol functional group to NPs surface. Consequently, the effective phase transfer of AuNPs from water to toluene did not occur. In toluene the most stable were nanoparticles modified with 1-decanethiol, 1-dodecanethiol and 1-tetradecanethiol.This work was supported by FP7-NMP-2010-SMALL-4 program (HYMEC), project number 263073. Scientific work supported by the Polish Ministry of Science and Higher Education, funds for science in 2011–2014 allocated for the cofounded international project

    A Rough and Narrow Path: Preserving Native American Religious Liberty in the Smith Era

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    Treatment of the Crippled Child in Milwaukee County with Special Emphasis on the Junior League Curative Workshop

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    Beethoven was deaf. Milton was blind. Pasteur suffered a paralytic stroke. Franklin D. Roosevelt had infantile paralysis. What was the technique with which they handled their limitations? How can cripples today overcome their handicaps? What aids are given to them in this century of the child

    Versatile Phase Transfer Method for the Efficient Surface Functionalization of Gold Nanoparticles: Towards Controlled Nanoparticle Dispersion in a Polymer Matrix

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    In electronic devices based on hybrid materials such as nonvolatile memory elements (NVMEs), it is essential to control precisely the dispersion of metallic nanoparticles (NPs) in an insulating polymer matrix such as polystyrene in order to control the functionality of the device. In this work the incorporation of AuNPs in polystyrene films is controlled by tuning the surface functionalization of the metallic nanoparticles via ligand exchange. Two ligands with different structures were used for functionalization: 1-decanethiol and thiol-terminated polystyrene. This paper presents a versatile method for the modification of gold nanoparticles (AuNPs) with thiol-terminated polystyrene ligands via phase transfer process. An organic colloid of AuNPs (5±1 nm diameter) is obtained by the phase transfer process (from water to toluene) that allows exchanging the ligand adsorbed on AuNPs surface (hydrophilic citrate/tannic acid to hydrophobic thiols). The stability, size distribution, and precise location of modified AuNPs in the polymer matrix are obtained from UV-Vis spectroscopy, dynamic light scattering (DLS), and electron tomography. TEM tomographic 3D imaging demonstrates that the modification of AuNPs with thiol-terminated polystyrene results in homogeneous particle distribution in the polystyrene matrix compared to 1-decanethiol modified AuNPs for which a vertical phase separation with a homogeneous layer of AuNPs located at the bottom of the polymer matrix was observed.This work was supported by FP7-NMP-2010-SMALL-4 Program (“Hybrid Organic/Inorganic Memory Elements for Integration of Electronic and Photonic Circuitry,” HYMEC), Project no. 263073. Eric Gonthier is acknowledged for technical support in the preparation of hybrid thin films. Scientific work was supported by the Polish Ministry of Science and Higher Education Funds for Science in 2011–2014 allocated for the cofunded international project

    A Comparison of John Dryden\u27s Prose with that of John Henry Newman

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    In order to gain a clear idea of this thesis, it is necessary to sketch briefly each author\u27s life. Thus we will be able to distinguish the various characteristics of their early careers. This will aid in clearing up points which, otherwise would seem difficult, without any prelimin­ary knowledge of each man\u27s life. John Dryden was born in 1631 at Aldwinkle in Northamptonshire, his parents being members of the upper middle class and of Puritan sympathies. He was sent.to the Westminster school, and thence in 1650 to Trinity College Cambridge, where he remained at least seven years. During this time his father died leaving him a small property . His first works of importance were such poems as an elegy on the death of Cromwell and another poem entitled Astraea Redux which welcomed the return of the Stuarts. He soon abandoned the Puritanical belief and became an ardent Royalist, because he, too, was weary of the chaotic refine and anxious for the return of justice

    The tetanic depression in fast motor units of mammalian skeletal muscle can be evoked by lengthening of one initial interpulse interval

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    A lower than expected tetanic force (the tetanic depression) is regularly observed in fast motor units (MUs) when a higher stimulation frequency immediately follows a lower one. The aim of the present study was to determine whether prolongation of only the first interpulse interval (IPI) resulted in tetanic depression. The experiments were carried out on fast MUs of the medial gastrocnemius muscle in cats and rats. The tetanic depression was measured in each case as the force decrease of a tetanus with one IPI prolonged in relation to the tetanic force at the respective constant stimulation frequency. Force depression was observed in all cases studied and was considerably greater in cats. For cats, the mean values of force depression amounted to 28.64% for FR and 10.86% for FF MUs whereas for rats 9.30 and 7.21% for FR and FF motor units, respectively. Since the phenomenon of tetanic depression in mammalian muscle is commonly observed even after a change in only the initial interpulse interval within a stimulation pattern, it can effectively influence processes of force regulation during voluntary activity of a muscle, when motoneurones progressively increase the firing rate

    Essay: Recent Developments in Minnesota Dram Shop Law

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    Minnesota\u27s Civil Damages Act is a creature of statute without counterpart in common law. The Act, referred to as the “Dram Shop Act,” is highly penal in nature and is intended to provide remedies for damages attributable to commercial lenders\u27 illegal sale of intoxicating liquors. Since the Act\u27s inception more than ninety-two years ago, Minnesota courts traditionally have construed it in a strict fashion. Over its long evolution, the “duet” of legislative action and court interpretation served to clarify several ambiguities within the Act. Despite precise and oftentimes circumstantial application, certain ambiguities remain. The following article will--in the context of recent Minnesota Dram Shop decisions--analyze the ambiguities in Dram Shop law and recommend clarifications in these areas
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