2,643 research outputs found

    A House Divided--The Schism Doctrine

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    Active and Unidirectional Acceleration of Biaryl Rotation by a Molecular Motor

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    Light‐driven molecular motors possess immense potential as central driving units for future nanotechnology. Integration into larger molecular setups and transduction of their mechanical motions represents the current frontier of research. Herein we report on an integrated molecular machine setup allowing the transmission of potential energy from a motor unit onto a remote receiving entity. The setup consists of a motor unit connected covalently to a distant and sterically encumbered biaryl receiver. By action of the motor unit, single‐bond rotation of the receiver is strongly accelerated and forced to proceed unidirectionally. The transmitted potential energy is directly measured as the extent to which energy degeneration is lifted in the thermal atropisomerization of this biaryl. Energy degeneracy is reduced by more than 1.5 kcal mol−1, and rate accelerations of several orders of magnitude in terms of the rate constants are achieved

    Green light powered molecular state motor enabling eight-shaped unidirectional rotation

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    Molecular motors convert external energy into directional motions at the nano-scales. To date unidirectional circular rotations and linear motions have been realized but more complex directional trajectories remain unexplored on the molecular level. In this work we present a molecular motor powered by green light allowing to produce an eight-shaped geometry change during its unidirectional rotation around the central molecular axis. Motor motion proceeds in four different steps, which alternate between light powered double bond isomerizations and thermal hula-twist isomerizations. The result is a fixed sequence of populating four different isomers in a fully unidirectional trajectory possessing one crossing point. This motor system opens up unexplored avenues for the construction and mechanisms of molecular machines and will therefore not only significantly expand the toolbox of responsive molecular devices but also enable very different applications in the field of miniaturized technology than currently possible

    Be My Little Baby Bumble Bee

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    https://digitalcommons.library.umaine.edu/mmb-vp/1077/thumbnail.jp

    Bibliographical Notes for The Press in Australia and Related Subjects

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    These Notes are pretty haphazard and do not meet the minimum standards of a bibliography or even of a checklist. They are the by-product of my book, The Press in Australia (Lansdowne Press, Melbourne, 1964). They consist largely of a listing of material I read in doing research on this book, supplemented by some entries which are taken from the results of a questionnaire sent to all metropolitan newspapers. I would like to thank the editors and librarians who furnished entries. The bulk of the book deals with 20th Century Australian metropolitan dailies. I began by making a survey of existing book and pamphlets on these, and in this field the Notes are most complete. For my historical chapter, which deals with some aspects of our 19th Century press, I did three main things: First, I sampled a cross section of dailies in 25 year periods. Second, I checked all books which were subject-indexed in the Mitchell catalogue. The entries for these, in fuller and more precise form, are given in the Notes. Third, I was faced with the problem of how to get [at] primary sources without consulting either manuscripts or Government documents. After spending some weeks on both, I decided that a thorough search would take up too much time relative to my short chapter. I hence switched to making a systematic check of 100 journal and magazine titles. The Mitchell catalogue lists some of them by states, but its selection is very incomplete. As it would have been folly to go through the whole catalogue, I began by checking all promising periodicals mentioned in Frank S. Greenop's History of Magazine Publishing in Australia, and all titles mentioned in H.M. Green's A History of Australian Literature. These were supplemented by entries from Ferguson's bibliography and by a check under likely titles in the catalogue, e.g. "Australian ...", "Sydney ...", "Colonial ..." etc. The periodicals often had references to their contemporaries, which were also used. This gave me a rough-and-ready list, which met two essential requirements: It covered a long period, and it contained periodicals from all states. I recognize, of course, that this was not a systematic sampling – but in order to draw a sample one would have needed a complete bibliography of titles. The period of checking depended on the length of the run, and the apparent promise of the periodical. The material was then supplemented by consulting The Bulletin Index, 1880-90. The entries given here are a selection from that index, and include only the longer and more informative pieces. As usual, the scope of the book as published is much narrower than its scope at first conceived. I have included entries on a number of subjects marginal to the daily metropolitan press, but of course these are very incomplete. So far as location is concerned, nearly all the books and most of the periodicals mentioned are in the Mitchell Library. But the Library does not contain some of the "House Organs" and "Cadet" papers mentioned. It is rather spotty so far as pamphlets are concerned, and perhaps 10-20% of the pamphlets mentioned here are not in the Mitchell. Apart from the Mitchell, I also checked the catalogues of the State Public Library of Victoria and of the National Library of Australia. My book contains some material based on semi-confidential surveys conducted by Anderson Analysis etc. These reports have not been included here, as they do not seem to be in any Public Library

    Sunlight-powered kHz rotation of a hemithioindigo-based molecular motor

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    Photodriven molecular motors are able to convert light energy into directional motion and hold great promise as miniaturized powering units for future nanomachines. In the current state of the art, considerable efforts have still to be made to increase the efficiency of energy transduction and devise systems that allow operation in ambient and non-damaging conditions with high rates of directional motions. The need for ultraviolet light to induce the motion of virtually all available light-driven motors especially hampers the broad applicability of these systems. We describe here a hemithioindigo-based molecular motor, which is powered exclusively by nondestructive visible light (up to 500 nm) and rotates completely directionally with kHz frequency at 20 degrees C. This is the fastest directional motion of a synthetic system driven by visible light to date permitting materials and biocompatible irradiation conditions to establish similarly high speeds as natural molecular motors

    Uterine phosphatase concentrations and their relationship to number and weight of embryos in the rat

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    This bulletin reports on Department of Agricultural Chemistry Research Project 223, 'Reproductive Physiology', and Department of Animal Husbandry Research Project 222--P. [3].Digitized 2007 AES.Includes bibliographical references (page 19)

    Mejora de un sistema de gestión de SEGDAD y salud en el trabajo para disminuir el número de accidentes en las obras civiles del centro comercial - 2017.

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    RESUMEN La empresa Centenario Retail S.A.C. toma la decisión de invertir S/. 100 millones para remodelar el diseño del Centro Comercial con el fin de optimizar y ser eficientes con los espacios y áreas comunes ya que el Core del negocio es el alquiler de espacios para locales comerciales En enero del 2017 se inician las obras de construcción civil para la remodelación del Centro Comercial. Luego de iniciar el proyecto de remodelación con tres (03) constructoras reconocidas en su rubro se asignan distintos frentes de trabajo donde observamos en los meses de enero, febrero y marzo un incremento significativo de accidente laborales en las obras de construcción civil, la cual nos exige tomar medidas para disminuir el incremento de accidentes por medio de una mejora en el sistema de gestión de seguridad y salud en el trabajo para del centro comercial 2017. Palabras claves: Variable X, Variable Y, dimensiones, etc.ABSTRACT The company Centenario Retail S.A.C. takes the decision to invest S /. 100 million to remodel the design of the Shopping Center in order to optimize and be efficient with the spaces and common areas since the Core of the business is the rental of spaces for commercial premises In January 2017, civil construction works began for the remodeling of the Shopping Center. After starting the remodeling project with three (03) construction companies recognized in their area are assigned different work fronts when we observe in January, February and March a significant increase in work accidents in civil construction works, which It requires taking measures to reduce the increase in accidents through an improvement in the occupational safety and health management system for the shopping center 2017
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