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- Bouyoucef, S E, et al.
(författare)
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Poster Session 2 : Monday 4 May 2015, 08
- 2015
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Ingår i: European Heart Journal Cardiovascular Imaging. - : Oxford University Press (OUP). - 2047-2404 .- 2047-2412. ; 16 Suppl 1
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Tidskriftsartikel (refereegranskat)
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2. |
- Sun, D. Z., et al.
(författare)
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Effective elastic properties of a van der Waals molecular monolayer at a metal surface
- 2010
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Ingår i: Physical Review B - Condensed Matter and Materials Physics. - 2469-9950 .- 2469-9969. ; 82:20
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Tidskriftsartikel (refereegranskat)abstract
- Adsorbing anthracene on a Cu(111) surface results in a wide range of complex and intriguing superstructures spanning a coverage range from 1 per 17 to 1 per 15 substrate atoms. In accompanying first-principles density-functional theory calculations we show the essential role of van der Waals interactions in estimating the variation in anthracene adsorption energy and height across the sample. We can thereby evaluate the compression of the anthracene film in terms of continuum elastic properties, which results in an effective Young's modulus of 1.5 GPa and a Poisson ratio approximate to 0.1. These values suggest interpretation of the molecular monolayer as a porous material-in marked congruence with our microscopic observations.
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3. |
- Nielsen, M, et al.
(författare)
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Gender-related variables for health research
- 2021
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Ingår i: Biology of Sex Differences. - : BioMed Central. - 2042-6410. ; 12:23
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Tidskriftsartikel (refereegranskat)abstract
- BackgroundIn this paper, we argue for Gender as a Sociocultural Variable (GASV) as a complement to Sex as a Biological Variable (SABV). Sex (biology) and gender (sociocultural behaviors and attitudes) interact to influence health and disease processes across the lifespan—which is currently playing out in the COVID-19 pandemic. This study develops a gender assessment tool—the Stanford Gender-Related Variables for Health Research—for use in clinical and population research, including large-scale health surveys involving diverse Western populations. While analyzing sex as a biological variable is widely mandated, gender as a sociocultural variable is not, largely because the field lacks quantitative tools for analyzing the influence of gender on health outcomes.MethodsWe conducted a comprehensive review of English-language measures of gender from 1975 to 2015 to identify variables across three domains: gender norms, gender-related traits, and gender relations. This yielded 11 variables tested with 44 items in three US cross-sectional survey populations: two internet-based (N = 2051; N = 2135) and a patient-research registry (N = 489), conducted between May 2017 and January 2018.ResultsExploratory and confirmatory factor analyses reduced 11 constructs to 7 gender-related variables: caregiver strain, work strain, independence, risk-taking, emotional intelligence, social support, and discrimination. Regression analyses, adjusted for age, ethnicity, income, education, sex assigned at birth, and self-reported gender identity, identified associations between these gender-related variables and self-rated general health, physical and mental health, and health-risk behaviors.ConclusionOur new instrument represents an important step toward developing more comprehensive and precise survey-based measures of gender in relation to health. Our questionnaire is designed to shed light on how specific gender-related behaviors and attitudes contribute to health and disease processes, irrespective of—or in addition to—biological sex and self-reported gender identity. Use of these gender-related variables in experimental studies, such as clinical trials, may also help us understand if gender factors play an important role as treatment-effect modifiers and would thus need to be further considered in treatment decision-making.
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4. |
- Wyrick, J., et al.
(författare)
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Do Two-Dimensional "Noble Gas Atoms" Produce Molecular Honeycombs at a Metal Surface?
- 2011
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Ingår i: Nano Letters. - : American Chemical Society (ACS). - 1530-6992 .- 1530-6984. ; 11:7, s. 2944-2948
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Tidskriftsartikel (refereegranskat)abstract
- Anthraquinone self-assembles on Cu(111) into a giant honeycomb network with exactly three molecules on each side. Here we propose that the exceptional degree of order achieved in this system can be explained as a consequence of the confinement of substrate electrons in the pores, with the pore size tailored so that the confined electrons can adopt a noble-gas-like two-dimensional quasi-atom configuration with two filled shells. Formation of identical pores in a related adsorption system (at different overall periodicity due to the different molecule size) corroborates this concept. A combination of photoemission spectroscopy with density functional theory computations (including van der Waals interactions) of adsorbate-substrate interactions allows quantum mechanical modeling of the spectra of the resultant quasi-atoms and their energetics.
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5. |
- Berland, Kristian, 1983, et al.
(författare)
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Response of the Shockley surface state to an external electrical field: A density-functional theory study of Cu(111)
- 2012
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Ingår i: Physical Review B - Condensed Matter and Materials Physics. - 2469-9950 .- 2469-9969. ; 85:3
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Tidskriftsartikel (refereegranskat)abstract
- The response of the Cu(111) Shockley surface state to an external electrical field is characterized by combining a density-functional theory calculation for a slab geometry with an analysis of the Kohn-Sham wave functions. Our analysis is facilitated by a decoupling of the Kohn-Sham states via a rotation in Hilbert space. We find that the surface state displays isotropic dispersion, quadratic until the Fermi wave vector but with a significant quartic contribution beyond. We calculate the shift in energetic position and effective mass of the surface state for an electrical field perpendicular to the Cu(111) surface; the response is linear over a broad range of field strengths. We find that charge transfer occurs beyond the outermost copper atoms and that accumulation of electrons is responsible for a quarter of the screening of the electrical field. This allows us to provide well converged determinations of the field-induced changes in the surface state for a moderate number of layers in the slab geometry.
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6. |
- Berland, Kristian, 1983, et al.
(författare)
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Rings sliding on a honeycomb network: Adsorption contours, interactions, and assembly of benzene on Cu(111)
- 2009
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Ingår i: Physical Review B - Condensed Matter and Materials Physics. - 2469-9950 .- 2469-9969. ; 80:15, s. 155431-
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Tidskriftsartikel (refereegranskat)abstract
- Using a van der Waals density functional (vdW-DF) [Phys. Rev. Lett. 92, 246401 (2004)], we perform ab initio calculations for the adsorption energy of benzene (Bz) on Cu(111) as a function of lateral position and height. We find that the vdW-DF inclusion of nonlocal correlations (responsible for dispersive interactions) changes the relative stability of eight binding-position options and increases the binding energy by over an order of magnitude, achieving good agreement with experiment. The admolecules can move almost freely along a honeycomb web of “corridors” passing between fcc and hcp hollow sites via bridge sites. Our diffusion barriers (for dilute and two condensed adsorbate phases) are consistent with experimental observations. Further vdW-DF calculations suggest that the more compact (hexagonal) Bz-overlayer phase, with lattice constant a=6.74 Å, is due to direct Bz-Bz vdW attraction, which extends to ~8 Å. We attribute the second, sparser hexagonal Bz phase, with a=10.24 Å, to indirect electronic interactions mediated by the metallic surface state on Cu(111). To support this claim, we use a formal Harris-functional approach to evaluate nonperturbationally the asymptotic form of this indirect interaction. Thus, we can account well for benzene self-organization on Cu(111).
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7. |
- Hyldgaard, Per, 1964, et al.
(författare)
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Interactions Mediated by Surface State: From Pairs and Trios to Adchains and Ordered Overlayers
- 2004
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Ingår i: Journal of Crystal Growth. ; 275, s. 1637-
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Tidskriftsartikel (refereegranskat)abstract
- Since metallic surface states on (1 1 1) noble metals are free-electron like, their propagators can be evaluated analytically. Since they are well-screened, one can use simple tight-binding formalism to study their effects. The needed phase shifts can be extracted from the experiment. Hence, one can now make quantitative predictions of these slowly-decaying, oscillatory indirect interactions. For the (isotropic!) pair interactions (which decay as the inverse square of adatom–adatom separation), remarkable agreement has been obtained with experiments by two groups. We have extended the formalism to consider the full indirect (“triple”) interaction of 3 adsorbates, which is the sum of the 3 constituent pair interactions plus the non-pairwise “trio” contribution, which tends to decay with the View the MathML source power of perimeter. Here, we concentrate on interactions due to ordered overlayers and to linear defects, relating the latter to the interactions of (n×1) ordered overlayers and both to the constituent pair and trio interactions. We compare with the experimental studies of interactions of adatoms with adchains and of consequent 1D motion of adatoms trapped between two such parallel chains. We discuss the implications for step–step interactions (on vicinal surfaces), with attention to the modification of the surface state itself for small terrace widths.
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