1,175 research outputs found

    Origin of the Mosaicity in Graphene Grown on Cu(111)

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    We use low-energy electron microscopy to investigate how graphene grows on Cu(111). Graphene islands first nucleate at substrate defects such as step bunches and impurities. A considerable fraction of these islands can be rotationally misaligned with the substrate, generating grain boundaries upon interisland impingement. New rotational boundaries are also generated as graphene grows across substrate step bunches. Thus, rougher substrates lead to higher degrees of mosaicity than do flatter substrates. Increasing the growth temperature improves crystallographic alignment. We demonstrate that graphene growth on Cu(111) is surface diffusion limited by comparing simulations of the time evolution of island shapes with experiments. Islands are dendritic with distinct lobes, but unlike the polycrystalline, four-lobed islands observed on (100)-textured Cu foils, each island can be a single crystal. Thus, epitaxial graphene on smooth, clean Cu(111) has fewer structural defects than it does on Cu(100).Comment: Article revised following reviewer comment

    Feasibility of using the Fitbit Charge HR in validating self-reported exercise diaries in a community setting in patients with heart failure

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    Background: Use of wrist-worn activity monitors has increased over the past few years; however, the use of the Fitbit® Charge HR (FCHR) in a community setting in patients with heart failure has not been tested. Purpose: The purpose of the study was to assess the feasibility, practicality and acceptability of utilizing the FCHR to validate self-reported exercise diaries and monitor exercise in community dwelling patients with heart failure. Methods: Thirty heart failure patients (12 females and 18 males) aged 64.7 ± 11.5 years were provided with a FCHR. Participants were provided with an exercise routine and for eight weeks, recorded their exercise sessions in self-reported exercise diaries and used the FCHR to record those exercise sessions. Results: Exercise data from the self-reported exercise diaries were validated with data from the FCHR. Participants’ perception and acceptance of using the FCHR was positive. Validation of exercise and physical activity interventions using the FCHR appears feasible and acceptable in patients with heart failure. Conclusion: Wrist-worn activity monitors can be useful for objective measurement of exercise adherence and monitoring of physical activity in patients with heart failure in a community setting

    Developing a Rapid Assessment Program for Student Success in Clinical Education

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    Successful management of the struggling student in the clinic relies heavily on the early identification of clinical performance deficits. CIs who directly observe student performance, actions and behaviors should aim for early and precise identification of difficulties, which should lead to initial discussions with the student. If the student\u27s struggles require involvement from the educational institution, the CI should promptly contact and collaborate with the DCE. Early communication with the DCE is beneficial, as they can provide support for CIs overwhelmed by the difficulties that accompany working with a challenging student. The DCE provides guidance on determining the depth of deficiencies, the student’s needs, and options for remediation. The Rapid Student Assessment and Review (R-STAR) Program was designed to facilitate a thorough and timely review of students’ Clinical Performance Instruments (CPIs)through partnership with expert clinical education faculty. With the increasing number of students in programs and the competing demands on Clinical Instructors (CIs), the successful management of the struggling student in the clinic relies heavily on the early identification of clinical performance deficits. Judicious review of CPI ratings and narratives is essential to identify discrepancies between the scores given and narrative comments. The R-STAR Program utilizes clinical partners who were carefully selected and specifically trained to review and provide feedback to students and CIs, while identifying those individuals with issues requiring the DCE to prioritize and address. This session describes how to develop an efficient and effective program that may be implemented to help facilitate the timely management of student assessments in clinical education to enhance success

    Smart Power Supply for Battery-Powered Systems

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    A power supply for battery-powered systems has been designed with an embedded controller that is capable of monitoring and maintaining batteries, charging hardware, while maintaining output power. The power supply is primarily designed for rovers and other remote science and engineering vehicles, but it can be used in any battery alone, or battery and charging source applications. The supply can function autonomously, or can be connected to a host processor through a serial communications link. It can be programmed a priori or on the fly to return current and voltage readings to a host. It has two output power busses: a constant 24-V direct current nominal bus, and a programmable bus for output from approximately 24 up to approximately 50 V. The programmable bus voltage level, and its output power limit, can be changed on the fly as well. The power supply also offers options to reduce the programmable bus to 24 V when the set power limit is reached, limiting output power in the case of a system fault detected in the system. The smart power supply is based on an embedded 8051-type single-chip microcontroller. This choice was made in that a credible progression to flight (radiation hard, high reliability) can be assumed as many 8051 processors or gate arrays capable of accepting 8051-type core presently exist and will continue to do so for some time. To solve the problem of centralized control, this innovation moves an embedded microcontroller to the power supply and assigns it the task of overseeing the operation and charging of the power supply assets. This embedded processor is connected to the application central processor via a serial data link such that the central processor can request updates of various parameters within the supply, such as battery current, bus voltage, remaining power in battery estimations, etc. This supply has a direct connection to the battery bus for common (quiescent) power application. Because components from multiple vendors may have differing power needs, this supply also has a secondary power bus, which can be programmed a priori or on-the-fly to boost the primary battery voltage level from 24 to 50 V to accommodate various loads as they are brought on line. Through voltage and current monitoring, the device can also shield the charging source from overloads, keep it within safe operating modes, and can meter available power to the application and maintain safe operations

    A nuclear localization signal targets tail-anchored membrane proteins to the inner nuclear envelope in plants

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    Protein targeting to the inner nuclear membrane (INM) is one of the least understood protein targeting pathways. INM proteins are important for chromatin organization, nuclear morphology and movement, and meiosis, and have been implicated in human diseases. In opisthokonts, one mechanism for INM targeting is transport factor-mediated trafficking, in which nuclear localization signals (NLSs) function in nuclear import of transmembrane proteins. To explore whether this pathway exists in plants, we fused the SV40 NLS to a plant ER tail-anchored protein and showed that the GFP-tagged fusion protein was significantly enriched at the nuclear envelope (NE) of leaf epidermal cells. Airyscan subdiffraction limited confocal microscopy showed that this protein displays a localization consistent with an INM protein. Nine different monopartite and bipartite NLSs from plants and opisthokonts, fused to a chimeric tail-anchored membrane protein, were all sufficient for NE enrichment, and both monopartite and bipartite NLSs were sufficient for trafficking to the INM. Tolerance for different linker lengths and protein conformations suggests that INM trafficking rules might differ from those in opisthokonts. The INM proteins developed here can be used to target new functionalities to the plant nuclear periphery

    A stereospecific one-pot synthesis of β-chloro esters via the BiCl<inf>3</inf> catalysed O-acylative cleavage of crowded epoxides

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    © 2015, Science Reviews 2000 Ltd. All rights reserved. A simple, one-pot procedure is described for the stereospecific preparation of β-chloro esters from the corresponding crowded epoxide

    MOVE-HF: an internet-based pilot study to improve adherence to exercise in patients with heart failure

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    Aim: The use of the internet and newer activity monitors such as the Fitbit Charge HR to improve exercise adherence is limited. The primary aim of the Move on Virtual Engagement (MOVE-HF) was to investigate the effects of group social support by internet-based synchronized face-to-face video and objective physical activity feedback on adherence to recommended exercise guidelines. Methods: Thirty stable heart failure patients (New York Heart Association class I–III), aged 64.7±11.5 years, were randomly assigned to an experimental or comparison group. Participants were provided a handout on self-care in heart failure, an exercise routine, a Fitbit Charge HR and were asked to wear the Fitbit Charge HR daily, and record their exercise sessions using both the Fitbit Charge HR and exercise diaries. In addition, participants in the experimental group connected to Vidyo software, once a week, for 8 weeks, for a 45-minute face-to-face online group discussion/education session. Results: Overall Vidyo session attendance was 68%, with 73% of participants attending five or more sessions. Adherence to exercise was 58.8% in the experimental group and 57.3% in the comparison group. The experimental group perceived receiving social support through the internet-based synchronized face-to-face video meetings but due to a small sample size and lack of adequate power, no significant impact on exercise adherence was observed. Participants commented that feedback regarding physical activity from the Fitbit Charge HR was helpful and motivational. Conclusion: Delivering social support by internet-based synchronized face-to-face video is feasible with heart failure patients. However, more investigations are needed to understand its impact on exercise adherence

    The hydrolysis of geminal ethers: A kinetic appraisal of orthoesters and ketals

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    © 2016 Repetto et al. A novel approach to protecting jet fuel against the effects of water contamination is predicated upon the coupling of the rapid hydrolysis reactions of lipophilic cyclic geminal ethers, with the concomitant production of a hydrophilic acyclic hydroxyester with de-icing properties (Fuel Dehydrating Icing Inhibitors - FDII). To this end, a kinetic appraisal of the hydrolysis reactions of representative geminal ethers was undertaken using a convenient surrogate for the fuel-water interface (D2 O/CD3 CN 1:4). We present here a library of acyclic and five/six-membered cyclic geminal ethers arranged according to their hydroxonium catalytic coefficients for hydrolysis, providing for the first time a framework for the development of FDII. A combination of 1H NMR, labelling and computational studies was used to assess the effects that may govern the observed relative rates of hydrolyses
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