| 1. |
- Piikki, Kristin, et al.
(författare)
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Estimates of AOT ozone indices from time-integrated ozone data and hourly air temperature measurements in southwest Sweden
- 2009
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Ingår i: Environmental Pollution. - : Elsevier. - 0269-7491 .- 1873-6424. ; 157:11, s. 3051-3058
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Tidskriftsartikel (refereegranskat)abstract
- Surface ozone concentration and surface air temperature was measured hourly at three coastal sites, four low elevation inland sites and two high elevation inland sites in southwestern Sweden. Diurnal ozone concentration range (DOR) and diurnal temperature range (DTR) were strongly correlated, both spatially and temporally, most likely because both depended on atmospheric stability. Accumulated ozone exposure above a threshold concentration of x nmol mol(-1) (AOTx) was estimated from time-integrated ozone concentration (as from diffusive sampling) and measures of ozone concentration variability. Two methods both estimated 24-h AOTx with high accuracy (modelling efficiencies >90% for x <= 40 nmol mol(-1)). Daytime (08:00-20:00) AOTx could not be equally well estimated. Estimates were better for lower AOT thresholds. Diffusive ozone concentration sampling, combined with hourly temperature monitoring, could be a valuable complement to ozone concentration monitoring with continuous instruments. (C) 2009 Elsevier Ltd. All rights reserved.
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| 2. |
- Agui, A., et al.
(författare)
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Direct observation of interface effects of thin AlAs(100) layers buried in GaAs
- 2000
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Ingår i: Applied Surface Science. - : Elsevier. - 0169-4332 .- 1873-5584. ; 166:1-4, s. 309-312
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Tidskriftsartikel (refereegranskat)abstract
- A study of the electronic structure of ultrathin AlAs layers buried in GaAs(100) and their interfaces is presented. Al L2,3 soft-X-ray-emission (SXE) spectra from the AlAs layers were measured. The spectra show distinct thickness-dependent features, which are reproduced using ab initio calculations.
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| 3. |
- Chauhan, H. S., et al.
(författare)
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Direct- and inverse-photoemission investigations of the electronic structure of Cd(0001)
- 1993
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Ingår i: Physical Review B Condensed Matter. - : American Physical Society. - 0163-1829 .- 1095-3795. ; 48:7, s. 4729-4734
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Tidskriftsartikel (refereegranskat)abstract
- Photoemission and inverse angle-resolved photoemission spectra are presented for Cd(0001). The data are interpreted in terms of interband transitions, density-of-states effects, and excitations of surface states.
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| 4. |
- de Peppo, G.M., et al.
(författare)
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Human Embryonic Mesodermal Progenitors Highly Resemble Human Mesenchymal Stem Cells and Display High Potential for Tissue Engineering Applications
- 2010
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Ingår i: Tissue Engineering. Part A. - : Mary Ann Liebert. - 1937-3341 .- 1937-335X. ; 16:7, s. 2161-2182
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Tidskriftsartikel (refereegranskat)abstract
- Adult stem cells, such as human mesenchymal stem cells (hMSCs), show limited proliferative capacity and, after long-term culture, lose their differentiation capacity and are therefore not an optimal cell source for tissue engineering. Human embryonic stem cells (hESCs) constitute an important new resource in this field, but one major drawback is the risk of tumor formation in the recipients. One alternative is to use progenitor cells derived from hESCs which are more lineage restricted but do not form teratomas. We have recently derived a cell line from hESCs denoted human embryonic stem cell-derived mesodermal progenitors (hESMPs) and here, using genome wide microarray analysis, report that the process of hES-MPs derivation results in a significantly altered expression of hESCs characteristic genes to an expression level highly similar to that of hMSCs. However, hES-MPs displayed a significantly higher proliferative capacity and longer telomeres. Interestingly, the hES-MPs also demonstrated a lower expression of HLA class II proteins before and after interferon-γ treatment, indicating that these cells may somewhat be immunoprivileged and potentially used for HLA-incompatible transplantation. The hES-MPs are thus an appealing alternative to hMSCs in tissue engineering applications and stem cell-based therapies for mesodermal tissues.
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| 5. |
- Mankefors, S., et al.
(författare)
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Ab initio calculations of soft-x-ray emission from Si(100) layers buried in GaAs
- 1998
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Ingår i: Physical Review B Condensed Matter. - : American Physical Society. - 0163-1829 .- 1095-3795. ; 58:16, s. 10551-10556
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Tidskriftsartikel (refereegranskat)abstract
- Calculations of soft-x-ray emission spectra from Si(100) layers buried in GaAs are reported. The local densities of states for Si in As and Ga sites are found to be very different. By comparison with experimental data, this difference allows us to determine the relative amounts of Si in the two types of sites. In the case of a single Si layer we find that 63 (±5)% of the buried atoms are in Ga sites.
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| 6. |
- Mankefors, S., et al.
(författare)
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Theoretical investigation of soft x-ray emission from a Si(100) layer buried in GaAs
- 1998
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Ingår i: Vacuum. - : Elsevier. - 0042-207X .- 1879-2715. ; 49:3, s. 181-184
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Tidskriftsartikel (refereegranskat)abstract
- Calculations of the soft x-ray emission spectrum have been carried out on a buried Si(100) layer in GaAs and compared with experimental data. We find that Si occupies Ga- as well as As-sites and that the local density of states is different for these two cases.
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| 7. |
- Mankefors, S., et al.
(författare)
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Theoretical investigation of the thickness dependence of soft-x-ray emission from thin AlAs(100) layers buried in GaAs
- 2000
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Ingår i: Physical Review B Condensed Matter. - : American Physical Society. - 0163-1829 .- 1095-3795. ; 61:8, s. 5540-5545
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Tidskriftsartikel (refereegranskat)abstract
- Ultrathin AlAs(100) layers of 1-, 2-, and 5-ML thickness buried in GaAs are investigated by ab initio calculations. Unique experimental soft-x-ray emission spectra are explained in terms of interface effects and changes with layer thickness are found in the density of states. Only the central layer in the 5-ML geometry is bulklike. A valence-band offset of 0.53 eV is also found for this structure, while no offset exists in the 1- and 2-ML cases. Very good agreement is achieved between theory and experiment.
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| 8. |
- Mankefors, S., et al.
(författare)
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Theoretical investigations of As overlayers on InP(110) surfaces
- 1997
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Ingår i: Physical Review B Condensed Matter. - : American Physical Society. - 0163-1829 .- 1095-3795. ; 56:24, s. 15847-15852
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Tidskriftsartikel (refereegranskat)abstract
- As adsorption and interaction with InP(110) is investigated by means of total-energy minimization calculations. We find that the As-P exchanged configuration has higher energy than the As/InP(110) epitaxially continued layer structure (ECLS), for all types of As reservoirs considered. In the presence of an additional As layer in ECLS (i.e., 1.5 ML adsorbed As), however, the exchanged configuration is only slightly higher in energy than the nonexchanged one. We conclude that the As-P exchange process is energetically unfavorable, and should in any case not be complete at room temperature, as suggested in a recent report. Our conclusion is supported by results of a photoemission study, including As adsorption, desorption, and redeposition, according to which the process is nonreversible.
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| 9. |
- Nilsson, P. O., et al.
(författare)
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Prediction of image-state excitation by secondary beams in inverse-photoemission spectroscopy
- 1993
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Ingår i: Physical Review B Condensed Matter. - : American Physical Society. - 0163-1829 .- 1095-3795. ; 47:19, s. 12968-12971
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Tidskriftsartikel (refereegranskat)abstract
- Excitation of image states is predicted to occur frequently in inverse-photoemission spectroscopy due to diffracted electron beams traveling almost parallel to the surface. A simple kinematic model, as well as full calculations using inverse low-energy electron-diffraction theory, show the effect in the case of Cd(0001).
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| 10. |
- Papadia, S., et al.
(författare)
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Electronic structure of metallic superlattices : Mo/V
- 1992
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Ingår i: Physical Review B Condensed Matter. - : American Physical Society. - 0163-1829 .- 1095-3795. ; 45:4, s. 1857-1868
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Tidskriftsartikel (refereegranskat)abstract
- The electronic structure for a metallic superlattice system, Mo/V, has been calculated using the linear muffin-tin orbital method in the atomic-sphere approximation (ASA). Total energies have been calculated in the local-density approximation (LDA). Emphasis has been given to the electronic-density variation in these materials in order to understand hydrogen storage in metallic superlattices. It is found, within effective-medium theory, that the balance between charge transfer at the interfaces and volume changes of the constituents determines preferred hydrogen sites in Mo/V. Total-energy considerations favor a tetragonal distortion of the Mo/V superlattice over a cubic structure. Results for the LDA bands, charge transfer, and density of states are compared to other electronic-structure calculations of metallic superlattices, which gives rise to a consistent picture of electronic effects in these systems. The dependence of the results on the ASA is discussed. © 1992 The American Physical Society.
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