468 research outputs found

    Sprawozdanie z sesji poświęconej pamięci prof. Jerzego A. Janika

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    Report of the Session Dedicated to Prof. J.A. Janik on the Occasion of the First Anniversary of his Deat

    Graphene on Pt(111): Growth and substrate interaction

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    In situ low-energy electron microscopy (LEEM) of graphene growth combined with measurements of the graphene structure and electronic band structure has been used to study graphene on Pt (111). Growth by carbon segregation produces macroscopic monolayer graphene domains extending continuously across Pt (111) substrate steps and bounded by strongly faceted edges. LEEM during cooling from the growth temperature shows the propagation of wrinkles in the graphene sheet, driven by thermal stress. The lattice mismatch between graphene and Pt (111) is accommodated by moiré structures with a large number of different rotational variants, without a clear preference for a particular interface geometry. Fast and slow growing graphene domains exhibit moiré structures with small [e.g., (3X3) G, (6X6) R2G, and (2X2) R4] and large unit cells [e.g., (44 x44) R15G, (52x52) R14G, and (8x8) G], respectively. A weak substrate coupling, suggested by the growth and structural properties of monolayer graphene on Pt (111), is confirmed by maps of the band structure, which is close to that of isolated graphene aside from minimal hole doping due to charge transfer from the metal. Finally, the decoupled graphene monolayer on Pt (111) appears impenetrable to carbon diffusion, which self-limits the graphene growth at monolayer thickness. Thicker graphene domains, which can form at boundaries between monolayer domains, have been used to characterize the properties of few-layer graphene on Pt (111)

    Graphene on Pt(111): Growth and substrate interaction

    Get PDF
    In situ low-energy electron microscopy (LEEM) of graphene growth combined with measurements of the graphene structure and electronic band structure has been used to study graphene on Pt (111). Growth by carbon segregation produces macroscopic monolayer graphene domains extending continuously across Pt (111) substrate steps and bounded by strongly faceted edges. LEEM during cooling from the growth temperature shows the propagation of wrinkles in the graphene sheet, driven by thermal stress. The lattice mismatch between graphene and Pt (111) is accommodated by moiré structures with a large number of different rotational variants, without a clear preference for a particular interface geometry. Fast and slow growing graphene domains exhibit moiré structures with small [e.g., (3X3) G, (6X6) R2G, and (2X2) R4] and large unit cells [e.g., (44 x44) R15G, (52x52) R14G, and (8x8) G], respectively. A weak substrate coupling, suggested by the growth and structural properties of monolayer graphene on Pt (111), is confirmed by maps of the band structure, which is close to that of isolated graphene aside from minimal hole doping due to charge transfer from the metal. Finally, the decoupled graphene monolayer on Pt (111) appears impenetrable to carbon diffusion, which self-limits the graphene growth at monolayer thickness. Thicker graphene domains, which can form at boundaries between monolayer domains, have been used to characterize the properties of few-layer graphene on Pt (111)

    Type 2 diabetes as a modifier of fibrin clot properties in patients with coronary artery disease

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    Altered fibrin clot structure has been reported both in patients with coronary artery disease (CAD) and those with type 2 diabetes mellitus (DM2). The aim of the present study was to evaluate plasma fibrin clot permeability and susceptibility to lysis in patients with DM2 and CAD. We studied 132 consecutive CAD patients, including 67 subjects with DM2, scheduled for elective coronary artery bypass grafting surgery. Ex vivo plasma fibrin clot permeability (K(s)) and lysis time (t(50%)) induced by 1 μg/mL recombinant tissue plasminogen activator (tPA), along with plasma levels of plasminogen activator inhibitor-1 (PAI-1), thrombin activatable fibrinolysis inhibitor (TAFI), tPA, von Willebrand factor (vWF), P-selectin, soluble CD40 ligand (sCD40L), were measured. Diabetic and non-diabetic patients did not differ in regard to demographics and remaining cardiovascular risk factors. Concomitant DM2 was associated with higher glucose (+24.3 %, p < 0.001), fibrinogen (+9.0 %, p = 0.037), PAI-1 (+58.7 %, p < 0.001), tPA (+24.0 %, p < 0.001) and P-selectin (+12.2 %, p < 0.001). Compared with the non-diabetic group, the CAD patients with DM2 had lower K(s) (-6.1 %, p = 0.02) and prolonged t(50%) (+5.1 %, p = 0.04). Multiple regression analysis of the whole study group showed that vWF, PAI-1, fibrinogen and DM2 were the independent predictors of t(50%) (R(2) = 0.58, p < 0.001), while only vWF was an independent predictor of K(s) (R(2) = 0.22, p < 0.001). This study indicates that DM2 is potent enough to unfavorably affect plasma fibrin clot characteristics despite abnormal clot phenotype typically observed in CAD. Of note, platelet and endothelial markers appear to contribute to fibrin clot properties in CAD concomitant with DM2

    Qualitative and quantitative differences in the motor and somatosensory cortical projections of the rat claustrum &#8212; combined retrograde transport and stereological studies

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    Using axonal retrograde tracing, combined with morphometric analysis, we compared the distribution and number of claustral neurons projecting to the motor and somatosensory cortical areas in the Wistar rat. Comparable volumes of the retrograde tracer Fluoro-Gold, were injected into the motor or somatosensory cortices. Injections into these areas resulted in labeling of neurons along the entire length of the claustrum. Neurons retrogradely labeled after injection into the motor cortex prevailed in the anterior part of the claustrum, whereas those projecting to the somatosensory cortex predominated in the central part. The mean number of claustral neurons retrogradely labeled after tracer injections into the motor cortex significantly outnumbered that from the somatosensory cortical area (

    Identification of clinical risk factors of atrial fibrillation in congestive heart failure

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    Background: Factors associated with the development of atrial fibrillation (AF) in generalpopulation have been described, but it is still unknown whether the same risk factors applyto heart failure (HF) patients. The aim of this study was to identify clinical factors related tovarious forms of AF in HF patients.Methods: The clinical and echocardiographic characteristics were assessed in 155 HF patients:50 with sinus rhythm, 52 with non-permanent AF, and 53 with permanent AF.Results: Multivariate logistic regression analysis showed that the increase in the NYHAclass was an independent risk factor for both forms of AF. The occurrence of permanent AF incomparison to sinus rhythm group was independently associated with hs-C-reactive protein(CRP) elevation above 1 mg/dL (OR 1.87, 95% CI 1.05–3.35), left atrial dimension above4 cm (OR 3.78, 95% CI 1.29–11.06) and tricuspid maximal pressure gradient elevation above35 mm Hg (OR 5.01, 95% CI 1.38–18.27). The presence of coronary disease was independentlyassociated with less frequent occurrence of permanent AF in comparison to sinus rhythm group(OR 0.21, 95% CI 0.06–0.67).Conclusions: More advanced congestive HF was associated with presence of both types of AF.Non-ischemic etiology of HF and elevated CRP are independently associated with permanentAF compared to sinus rhythm. Left ventricular diastolic dysfunction indicators (increasedtricuspid maximal pressure gradient and left artial dimension) are independently associatedwith permanent AF

    New nondestructive way of identifying the values of pull-off adhesion between concrete layers in floors

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    This paper presents a new nondestructive way of identifying the values of pull-off adhesion between the concrete layers in concrete floors. It based on the roughness parameters of the base layer surface, using the nondestructive optical technique, and on the floor surface, using the nondestructive acoustic techniques and employing artificial neural networks (ANNs) for this purpose. The new way has a potential for being widely used in practice, whereby it may become possible to employ previously trained ANNs to identify the pull-off adhesion, without impairing the surface of the tested concrete floor
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