895 research outputs found

    4-Ď€-Photocyclization of 1,2-Dihydropyridazines: An Approach to Bicyclic 1,2-Diazetidines with Rich Synthetic Potential.

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    The 4-Ď€-photocyclization of a range of 1,2-dihydropyridazines is described, generating bicyclic 1,2-diazetidines in high yields on multigram scale. The key bicyclic 1,2-diazetidines are versatile synthetic intermediates and were easily converted into a range of novel derivatives, including functionalized 1,2-diazetidines, cyclobutenes, cyclobutanes, and 1,3-dienes

    Localization of Interaction using Fibre-Optic Shape Sensing in Soft-Robotic Surgery Tools

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    Minimally invasive surgery requires real-time tool tracking to guide the surgeon where depth perception and visual occlusion present navigational challenges. Although vision-based and external sensor-based tracking methods exist, fibre-optic sensing can overcome their limitations as they can be integrated directly into the device, are biocompatible, small, robust and geometrically versatile. In this paper, we integrate a fibre Bragg grating-based shape sensor into a soft robotic device. The soft robot is the pneumatically attachable flexible (PAF) rail designed to act as a soft interface between manipulation tools and intra-operative imaging devices. We demonstrate that the shape sensing fibre can detect the location of the tools paired with the PAF rail, by exploiting the change in curvature sensed by the fibre when a strain is applied to it. We then validate this with a series of grasping tasks and continuous US swipes, using the system to detect in real-time the location of the tools interacting with the PAF rail. The overall location-sensing accuracy of the system is 64.6%, with a margin of error between predicted location and actual location of 3.75 mm

    Synthesis of (±)-Panduratin A and Related Natural Products Using the High Pressure Diels-Alder Reaction

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    Panduratin A and 4-hydroxypanduratin A are synthesised in 6 steps via a high pressure Diels-Alder reaction. This sequence has also allowed the synthesis of isopanduratin A, 4-hyrdoxyisopanduratin A, panduratin H, and panduratin I. In addition the regioselectivity of the Diels-Alder reaction has been investigated.We thank the Australian Research Council for financial support. M.L.C thanks the National Facility of the National Computational Infrastructure for supercomputing time

    Interventions for preventing falls in people with multiple sclerosis.

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    This is a protocol for a Cochrane Review (Intervention). The aim of this review is to evaluate the effectiveness of interventions designed to reduce the rate of falls in people with multiple sclerosis (MS). Specific objectives include comparing the effectiveness of single, multiple and multifactorial interventions designed to reduce the rate of falls in people with MS

    Commentary on “Can a Good Philosophical Contribution Be Made Just By Asking a Question?”

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    This paper explains some of the reasoning behind “Can a Good Philosophical Contribution Be Made Just by Asking a Question?,” a paper which consists solely in its title and which is published in the same issue of the journal as the present paper. The method for explaining that reasoning consists in making available a lightly edited version of a letter the authors sent to the editors when submitting the title-only paper. The editors permitted publication of that paper on the condition that the authors also separately publish a version of that letter; the present paper aims to fulfil that condition

    Experimental and Theoretical Studies of the Redox Potentials of Cyclic Nitroxides

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    (Chemical Equation Presented) The redox potentials of 25 cyclic nitroxides from four different structural classes (pyrrolidine, piperidine, isoindoline, and azaphenalene) were determined experimentally by cyclic voltammetry in acetonitrile, and also via high-level ab initio molecular orbital calculations. It is shown that the potentials are influenced by the type of ring system, ring substituents and/or groups surrounding the radical moiety. For the pyrrolidine, piperidine, and isoindolines there is excellent agreement (mean absolute deviation of 0.05 V) between the calculated and experimental oxidation potentials; for the azaphenalenes, however, there is an extraordinary discrepancy (mean absolute deviation of 0.60 V), implying that their one-electron oxidation might involve additional processes not considered in the theoretical calculations. This recently developed azaphenalene class of nitroxide represents a new variant of a nitroxide ring fused to an aromatic system and details of the synthesis of five derivatives involving differing aryl substitution are also presented
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