| 1. |
- Trinh, David Huy, 1981-, et al.
(författare)
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Nanocomposite Al2O3-ZrO2 thin films grown by reactive dual radio-frequency magnetron sputtering
- 2008
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Ingår i: Thin Solid Films. - : Elsevier. - 0040-6090 .- 1879-2731. ; 516:15, s. 4977-4982
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Tidskriftsartikel (refereegranskat)abstract
- Crystalline alumina–zirconia nanocomposites have been synthesized at 450 °C and 750 °C with reactive magnetron sputtering using radio-frequency power supplies. The composition of the films ranged from pure alumina to pure zirconia as measured by ion beam techniques. Microstructural characterization showed the presence of monoclinic zirconia in the pure zirconia films and γ-alumina in the pure alumina films while the nanocomposites contained either an amorphous compound, γ-alumina, cubic zirconia or a mixture of these. The grain size was 5 nm for the nanocomposite compared to larger grains in the pure oxide films. Electron energy loss spectroscopy showed a clear progression from the pure alumina to the pure zirconia.
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| 2. |
- Trinh, David Huy, et al.
(författare)
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Radio frequency dual magnetron sputtering deposition and characterization of nanocomposite Al2O3-ZrO2 thin films
- 2006
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Ingår i: Journal of Vacuum Science & Technology. A. Vacuum, Surfaces, and Films. - : American Vacuum Society. - 0734-2101 .- 1520-8559. ; 24:2, s. 309-316
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Tidskriftsartikel (refereegranskat)abstract
- Radio frequency magnetron sputtering from oxide targets has been used to synthesize crystalline alumina–zirconia nanocomposites at a relatively low temperature of 450 °C. Films of different compositions have been deposited ranging from pure zirconia to pure alumina, the compositions being measured with Rutherford backscattering and elastic recoil detection analysis. X-ray diffraction studies show the presence of the monoclinic zirconia phase in pure zirconia films. Addition of alumina into the film results in the growth of the cubic zirconia phase and amorphous alumina. No crystalline alumina was detected in either the composite or the pure alumina film. The microstructure of the films as studied by high resolution electron microscopy and scanning transmission electron microscopy shows a columnar growth mode in both the pure zirconia and nanocomposite films, but reveals differences in the intracolumnar structure. For the nanocomposite small equiaxed grains, ~5 nm in size, are found at the base of the columns at the interface with the substrate. An amorphous tissue of alumina was present between the small crystallites in the case of the nanocomposite.
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| 5. |
- Kopp, J, et al.
(författare)
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Regulation of neuropeptide Y Y1 receptors by testosterone in vascular smooth muscle cells in rat testis
- 2008
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Ingår i: Neuroendocrinology. - : S. Karger AG. - 1423-0194 .- 0028-3835. ; 88:3, s. 216-226
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Tidskriftsartikel (refereegranskat)abstract
- It is well established that testosterone and neuropeptide Y (NPY), via its Y1 receptor (Y1R), are involved in the central control of the gonadotrope axis in male rats. Here we examined if a similar interaction also occurs in the male peripheral reproductive target organ, the testes. Expression of the Y1R transcript and protein and changes in testicular microcirculation were studied in normal rats and 12 days following hypophysectomy with and without testosterone substitution (1 or 25 mg s.c.). In situ hybridization and immunohistochemistry showed strong expression of, respectively, Y1R messenger RNA (Y1R mRNA) and Y1R-like immunoreactivity (Y1R-LI) in vascular smooth muscles in the testes of control and hypophysectomized rats treated with testosterone, but was not seen without testosterone substitution. In parallel, control animals and hypophysectomized, testosterone-supplemented rats showed a strong (approximately 40%) decrease in testicular blood flow following intratesticular (i.t.) injection of the Y1-R agonists, [Leu<sup>31</sup>, Pro<sup>34</sup>]NPY, [<i>D</i>-Arg<sup>25</sup>]NPY or NPY, an effect which was completely blocked by prior intravenous administration of the Y1R antagonist, BIBP3226. No significant change in testicular blood flow following i.t. injection of NPY was seen in hypophysectomized rats without testosterone substitution. These findings suggest that the high levels of Y1R mRNA and Y1R-LI in the testes reflect expression of functional Y1Rs mediating vasoconstriction, and that testosterone regulates expression of functional Y1Rs.
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| 6. |
- Linge, Helena M, et al.
(författare)
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The human CXC chemokine granulocyte chemotactic protein 2 (GCP-2)/CXCL6 possesses membrane-disrupting properties and is antibacterial
- 2008
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Ingår i: Antimicrobial Agents and Chemotherapy. - 1098-6596 .- 0066-4804. ; 52:7, s. 2599-2607
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Tidskriftsartikel (refereegranskat)abstract
- Granulocyte chemotactic protein 2 (GCP-2)/CXCL6 is a CXC chemokine expressed by macrophages and epithelial and mesenchymal cells during inflammation. Through binding and activation of its receptors (CXCR1 and CXCR2), it exerts neutrophil-activating and angiogenic activities. Here we show that GCP-2/CXCL6 itself is antibacterial. Antibacterial activity against gram-positive and gram-negative pathogenic bacteria of relevance to mucosal infections was seen at submicromolar concentrations (minimal bactericidal concentration at which 50% of strains tested were killed, 0.063 +/- 0.01 to 0.37 +/- 0.03 muM). In killed bacteria, GCP-2/CXCL6 associated with bacterial surfaces, which showed membrane disruption and leakage. A structural prediction indicated the presence of three antiparallel NH(2)-terminal beta-sheets and a short amphipathic COOH-terminal alpha-helix; the latter feature is typical of antimicrobial peptides. However, when the synthetic derivatives corresponding to the NH(2)-terminal (50 amino acids) and COOH-terminal (19 amino acids, corresponding to the putative alpha-helix) regions were compared, higher antibacterial activity was observed for the NH(2)-terminus-derived peptide, indicating that the holopeptide is necessary for full antibacterial activity. An artificial model of bacterial membranes confirmed these findings. The helical content of GCP-2/CXCL6 in the presence or absence of lipopolysaccharide or negatively charged membranes was studied by circular dichroism. As with many antibacterial peptides, membrane disruption by GCP-2/CXCL6 was dose-dependently reduced in the presence of NaCl, which, we here demonstrate, inhibited the binding of the peptide to the bacterial surface. Compared with CXC chemokines ENA-78/CXCL5 and NAP-2/CXCL7, GCP-2/CXCL6 showed a 90-fold-higher antibacterial activity. Taken together, GCP/CXCL6, in addition to its chemotactic and angiogenic properties, is likely to contribute to direct antibacterial activity during localized infection.
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| 7. |
- Luisa Mearin, M, et al.
(författare)
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European multi-centre study on coeliac disease and non-Hodgkin lymphoma.
- 2006
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Ingår i: European Journal of Gastroenterology and Hepathology. - 0954-691X .- 1473-5687. ; 18:2, s. 187-194
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Tidskriftsartikel (refereegranskat)abstract
- Introduction: Coeliac disease (CD) is associated with an increased risk of non-Hodgkin lymphoma (NHL), but there is little information about whether this is true for clinically silent CD. Objective: To investigate the frequency of CD in two European populations; one with NHL and another derived from the general population. Methods: A prospective, multi-centre, case-control study in 10 European countries was conducted between May 1998 and April 2001. A total of 1446 consecutive patients with newly diagnosed NHLaged over 18 years was collected. The control group consisted of a population of 9676 individuals who were screened for CD. The number of patients with a previous diagnosis of CD and those with silent CD detected by screening were determined in the two groups. Results: The patients with CD had a significantly increased risk of developing NHL [odds ratio (OR) 2.6, 95% confidence interval (CI) 1.4-4.9]. This risk was only present in patients with CD diagnosed clinically before the study (OR 3.3, 95% CI 1.4-7.9), but not in those with silent CD detected by screening (OR 1.3, 95% CI 0.6-2.7). Conclusion: Patients with CD have an increased risk of developing NHL, although this is lower than previously thought. Clinically silent CD is rare in patients with NHL.
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| 8. |
- Payer, Dietmar, et al.
(författare)
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Toward Mechanical Switching of Surface-Adsorbed [2]Catenane by in Situ Copper Complexation
- 2007
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Ingår i: Journal of the American Chemical Society. - Washington, DC, USA : American Chemical Society (ACS). - 0002-7863 .- 1520-5126. ; 129, s. 15662-15667
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Tidskriftsartikel (refereegranskat)abstract
- Using scanning tunneling microscopy (STM), electrospray ionization mass spectrometry (ESI-MS), and X-ray photoelectron spectroscopy (XPS), we demonstrate that a free [2]catenane consisting of two interlocking 30-membered rings (cat-30) can be deposited on a Ag(111) surface by vacuum sublimation without decomposition. The deposited cat-30 molecules self-organize as ordered dimer chain structures at the surface, presumably via intermolecular π−π stacking. An in situ addition of Cu atoms to the surface-adsorbed catenanes induces a drastic change in the molecular organization, i.e., from the dimer chain structure to isolated species. The nitrogen core level spectra suggest that the cat-30 phenanthroline units coordinate with Cu, indicating that the free catenane has been transformed into a Cu-complexed [2]catenane. Since it is known that the two interlocked macrocyclic rings of the free ligand cat-30 completely rearrange, i.e., circumrotate, upon complexation to copper, our results reveal that when adsorbed on the silver surface, the two macrocyclic rings of the free [2]catenane can glide within one another so as to generate the corresponding copper complex by in situ Cu complexation.
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| 9. |
- Pozina, Galia, et al.
(författare)
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Phase identification in γ- and κ-alumina coatings by cathodoluminescence
- 2009
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Ingår i: Scripta Materialia. - : Elsevier BV. - 1359-6462 .- 1872-8456. ; 61:4, s. 379-382
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Tidskriftsartikel (refereegranskat)abstract
- Cathodoluminescence (CL) properties were studied for metastable γ- and κ-Al2O3 coatings for cutting tool inserts. The alumina films demonstrate a strong CL, with peak energies depending on the Al2O3 polymorphs. The phase transformation caused by heat treatment is shown to correlate with strong CL modification in the annealed coatings. Spatially resolved CL is found to be a powerful nondestructive technique for identification of different alumina phases on the microscopic level. The corresponding optical properties of γ- and κ-Al2O3 are discussed.
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