1,334 research outputs found

    Electronic structure, imaging contrast and chemical reactivity of graphene moir\'e on metals

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    Realization of graphene moir\'e superstructures on the surface of 4d and 5d transition metals offers templates with periodically modulated electron density, which is responsible for a number of fascinating effects, including the formation of quantum dots and the site selective adsorption of organic molecules or metal clusters on graphene. Here, applying the combination of scanning probe microscopy/spectroscopy and the density functional theory calculations, we gain a profound insight into the electronic and topographic contributions to the imaging contrast of the epitaxial graphene/Ir(111) system. We show directly that in STM imaging the electronic contribution is prevailing compared to the topographic one. In the force microscopy and spectroscopy experiments we observe a variation of the interaction strength between the tip and high-symmetry places within the graphene moir\'e supercell, which determine the adsorption cites for molecules or metal clusters on graphene/Ir(111).Comment: submitted on Sep, 6th 201

    Graphene on Rh(111): STM and AFM studies

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    The electronic and crystallographic structure of the graphene/Rh(111) moir\'e lattice is studied via combination of density-functional theory calculations and scanning tunneling and atomic force microscopy (STM and AFM). Whereas the principal contrast between hills and valleys observed in STM does not depend on the sign of applied bias voltage, the contrast in atomically resolved AFM images strongly depends on the frequency shift of the oscillating AFM tip. The obtained results demonstrate the perspectives of application atomic force microscopy/spectroscopy for the probing of the chemical contrast at the surface.Comment: manuscript and supplementary information; submitted to Appl. Phys. Lett. on 01.03.201

    Scanning tunneling and atomic force microscopies studies

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    The electronic and crystallographic structure of the graphene/Rh(111) moiré lattice is studied via combination of density-functional theory calculations and scanning tunneling and atomic force microscopy(STM and AFM). Whereas the principal contrast between hills and valleys observed in STM does not depend on the sign of applied bias voltage, the contrast in atomically resolved AFM images strongly depends on the frequency shift of the oscillating AFM tip. The obtained results demonstrate the perspectives of application atomic force microscopy/spectroscopy for the probing of the chemical contrast at the surface

    Surface grafting of electrospun fibers using ATRP and RAFT for the control of biointerfacial interactions

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    BACKGROUND The ability to present signalling molecules within a low fouling 3D environment that mimics the extracellular matrix is an important goal for a range of biomedical applications, both in vitro and in vivo. Cell responses can be triggered by non-specific protein interactions occurring on the surface of a biomaterial, which is an undesirable process when studying specific receptor-ligand interactions. It is therefore useful to present specific ligands of interest to cell surface receptors in a 3D environment that minimizes non-specific interactions with biomolecules, such as proteins. METHOD In this study, surface-initiated atom transfer radical polymerization (SI-ATRP) of poly(ethylene glycol)-based monomers was carried out from the surface of electrospun fibers composed of a styrene/vinylbenzyl chloride copolymer. Surface initiated radical addition-fragmentation chain transfer (SI-RAFT) polymerisation was also carried out to generate bottle brush copolymer coatings consisting of poly(acrylic acid) and poly(acrylamide). These were grown from surface trithiocarbonate groups generated from the chloromethyl styrene moieties existing in the original synthesised polymer. XPS was used to characterise the surface composition of the fibers after grafting and after coupling with fluorine functional XPS labels. RESULTS Bottle brush type coatings were able to be produced by ATRP which consisted of poly(ethylene glycol) methacrylate and a terminal alkyne-functionalised monomer. The ATRP coatings showed reduced non-specific protein adsorption, as a result of effective PEG incorporation and pendant alkynes groups existing as part of the brushes allowed for further conjugation of via azide-alkyne Huisgen 1,3-dipolar cycloaddition. In the case of RAFT, carboxylic acid moieties were effectively coupled to an amine label via amide bond formation. In each case XPS analysis demonstrated that covalent immobilisation had effectively taken place. CONCLUSION Overall, the studies presented an effective platform for the preparation of 3D scaffolds which contain effective conjugation sites for attachment of specific bioactive signals of interest, as well as actively reducing non-specific protein interactions.This research was supported by the Cooperative Research Centre for Polymers (CRCP)

    Supporting smoking cessation in older patients: a continuing challenge for community nurses

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    Tobacco smoking continues to pose negative health consequences for smokers and their families, and is the single greatest cause of health inequalities in the UK. Older people are particularly vulnerable to the negative health impacts of smoking and therefore, supporting older smokers to quit remains an important public health goal. Community nurses are required to help patients to lead healthier lifestyles and have ideal opportunities to encourage smoking cessation in older people who are affected by smoking-related health conditions, or whose existing conditions may be exacerbated by continued smoking. This paper discusses how community nurses can support their older patients to quit smoking by fostering a patient-centred partnership through good communication and empathy. The newly developed ‘Very Brief Advice on Smoking’ (VBA) interventions can provide a useful tool for community nurses who experience time constraints to advise older people that psychosocial support with treatment is the most effective method of smoking cessation, while respecting the health decisions of patients

    Psychometric Evaluation and Design of Patient-Centered Communication Measures for Cancer Care Settings

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    Objective To evaluate the psychometric properties of questions that assess patient perceptions of patient-provider communication and design measures of patient-centered communication (PCC). Methods Participants (adults with colon or rectal cancer living in North Carolina) completed a survey at 2 to 3 months post-diagnosis. The survey included 87 questions in six PCC Functions: Exchanging Information, Fostering Health Relationships, Making Decisions, Responding to Emotions, Enabling Patient Self-Management, and Managing Uncertainty. For each Function we conducted factor analyses, item response theory modeling, and tests for differential item functioning, and assessed reliability and construct validity. Results Participants included 501 respondents; 46% had a high school education or less. Reliability within each Function ranged from 0.90 to 0.96. The PCC-Ca-36 (36-question survey; reliability=0.94) and PCC-Ca-6 (6-question survey; reliability=0.92) measures differentiated between individuals with poor and good health (i.e., known-groups validity) and were highly correlated with the HINTS communication scale (i.e., convergent validity). Conclusion This study provides theory-grounded PCC measures found to be reliable and valid in colorectal cancer patients in North Carolina. Future work should evaluate measure validity over time and in other cancer populations. Practice implications The PCC-Ca-36 and PCC-Ca-6 measures may be used for surveillance, intervention research, and quality improvement initiatives

    Report for Evaluation of Canonical SNP Taqman Assays to Detect Biothreat Agents and Environmental Samples for DHS

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    Abstract not provide

    Lessons Learned Developing an Extension-Based Training Program for Farm Labor Supervisors

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    This article outlines a four-step model for developing a training program for farm labor supervisors. The model draws on key lessons learned during the development of the University of Florida Institute of Food and Agricultural Sciences Farm Labor Supervisor Training program. The program is designed to educate farm supervisors on farm labor laws and to support compliance with workplace regulations critical for the safety of farmworkers and the economic sustainability of agricultural industries. Attentive to building partnerships, assessing needs, tailoring the curriculum, and conducting evaluations, the model can be applied elsewhere to address the farm labor issues confronted by specialty crop growers in other states

    The relationship between the insulin-like growth factor-1 axis, weight loss, an inflammation-based score and survival in patients with inoperable non-small cell lung cancer

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    <b>Background & aims:</b> The involvement of a systemic inflammatory response, as evidenced by the Glasgow Prognostic Score (GPS), is associated with weight loss and poor outcome in patients with non-small cell lung cancer. There is good evidence that nutritional and functional decline in patients with advanced malignant disease is associated with catabolic changes in metabolism. However, defects in anabolism may also contribute towards nutritional decline in patients with cancer. The aim of the present study was to examine the relationship between IGF-1 and IGFBP-3, performance status, mGPS and survival in patients with inoperable NSCLC. <b>Methods:</b> 56 patients with inoperable NSCLC were studied. The plasma concentrations of IGF-1, IGFBP-3 and leptin were measured using ELISA and RIA. <b>Results:</b> The patients were predominantly male (61%), over 60 years old (80%), with advanced (stage III or IV) disease (98%), with a BMI≥20 (84%), an ECOG-ps of 0 or 1 (79%), a haemoglobin (59%) and white cell count (79%) in the reference range. On follow-up 43 patients died of their cancer. On univariate analysis, BMI (p<0.05), Stage (p<0.05), ECOG-ps (p<0.05), haemoglobin (p<0.05), white cell count (p<0.05) and mGPS (p<0.05) were associated with cancer specific survival. There was no association between age, sex, treatment, IGF-1, IGFBP-3, IGF-1:IGFBP-3 ratio, or leptin and cancer specific survival. With an increasing mGPS concentrations of haemoglobin (p<0.005) and IGFBP-3 (p<0.05) decreased. mGPS was not associated with either IGF-1(p>0.20), or leptin (p>0.20). <b>Conclusions:</b> In summary, the results of this study suggest that anabolism (IGF-1 axis) does not play a significant role in the relationship between nutritional and functional decline, systemic inflammation and poor survival in patients with inoperable NSCLC

    Mode effects between computer self-administration and telephone interviewer-administration of the PROMIS® pediatric measures, self- and proxy report

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    To test equivalence of scores obtained with the PROMIS® pediatric Depressive Symptoms, Fatigue, and Mobility measures across two modes of administration: computer self-administration and telephone interviewer-administration. If mode effects are found, to estimate the magnitude and direction of the mode effects
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