| 1. |
- Aad, G., et al.
(författare)
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- 2012
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Ingår i: Journal of High Energy Physics. - 1029-8479 .- 1126-6708. ; :12
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Tidskriftsartikel (refereegranskat)
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| 2. |
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| 3. |
- D'Ippolito, Veronica, et al.
(författare)
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Color mechanisms in spinel: cobalt and iron interplay for the blue color
- 2015
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Ingår i: Physics and chemistry of minerals. - : Springer Science and Business Media LLC. - 0342-1791 .- 1432-2021. ; 42:6, s. 431-439
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Tidskriftsartikel (refereegranskat)abstract
- Six natural, blue colored spinel crystals were studied chemically by electron microprobe and laser ablation inductively coupled plasma mass spectrometry (LAICP-MS) techniques and optically by UV–VIS–NIR–MIR spectroscopy in the range 30,000–2,000 cm−1 to investigate the causes of their blue color hues. The positions of the absorption bands vary only marginally with the principal composition of the samples (gahnite vs. spinel s.s .). Although blue colors in spinels are frequently the result of various electronic processes in Fe cations, we demonstrate by comparison with synthetic Co-bearing samplesthat Co acts as an important chromophore also in natural spinels. Already at concentration levels of a few ppm (e.g.,>10 ppm), cobalt gives rise to absorption bands at ~18,000, 17,000 and 16,000 cm−1 that result in distinct blue coloration. In spinels with insignificant Co contents, different shades of paler blue (from purplish to greenish blue) colors are caused by electronic transitions in TFe2+, MFe2+, MFe3+ and Fe2+–Fe3+ cation pairs.
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| 4. |
- D'Ippolito, Veronica, et al.
(författare)
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Crystallographic and spectroscopic characterisation of a natural Zn-rich spinel approaching the endmember gahnite (ZnAl2O4) composition
- 2013
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Ingår i: Mineralogical magazine. - : Mineralogical Society. - 0026-461X .- 1471-8022. ; 77, s. 2941-2953
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Tidskriftsartikel (refereegranskat)abstract
- The crystal chemistry of a natural, gem-quality, blue-grey Zn-rich spinel crystal from Jemaa, Kaduna State, Nigeria, was studied using electron microprobe, single-crystal X-ray diffraction, optical absorption and Raman spectroscopies. The composition of the crystal approaches the gahnite endmember (ZnAl2O4), ∼94 mol.%, with the remainder being dominated by a hercynite component (FeAl2O4). The unit-cell dimension is 8.0850(3) Å and the tetrahedral and octahedral bond distances are determined asT–O 1.9485(6) Å andM–O 1.9137(3) Å. Crystal chemical analysis resulted in the empirical structural formulaT(Zn0.94Fe2+0.03Al0.03)M(Al1.96Fe2+0.03Fe3+0.01)O4, which shows Zn and Al almost fully ordered in the tetrahedrally and octahedrally coordinatedTandMsites, respectively. Raman spectra obtained using the excitation of the blue 473.1 nm line of a Nd:YAG laser display three of the five Raman-active modes predicted for the general oxide spinel group of minerals. These are the Egmode at 420.6 cm–1and the T2gmodes at 510 cm–1and 661 cm–1, due to vibrations in the AlO6octahedra. Optical absorption spectra recorded in the UV/VIS-NIR-MIR range 2000 29000 cm–1show a dominant absorption band at ∼5000 cm–1which is caused by spin-allowed electronicd–dtransitions in Fe2+located at theTsites. The blue-grey hue exhibited by the sample is mainly due to spin-forbidden electronic transitions inTFe2+and toMFe2+↔MFe3+intervalence charge transfer, and the poor saturation of the colour is due to the small concentration of Fe2+and Fe3+.
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| 5. |
- Sakao, Tomohiko, 1969-, et al.
(författare)
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Analysis of Integrated Product and Service Offerings from Current Perspectives of Providers and Customers
- 2009
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Ingår i: Proceedings of the 1st CIRP IPS<sup>2</sup> Conference. - Cranfield : Cranfield University Press. - 9780955743658 ; , s. 193-199
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Konferensbidrag (refereegranskat)abstract
- This paper reports the current status of how companies address IPSO (Integrated Product and Service Offerings)-typed business. It will consist of perspectives both from providers and customers mainly fromSweden and Germany. Especially, it selects how providing firms address uncertainty as one focal issue. As a result of interviews, factors from customers are the major source of uncertainty for an experiencedcompany, while services are the major for little experienced companies. In addition, there was found to be areasonable wish of providers to obtain a formalized way leading to quantitative management of uncertainty. On the other hand, customer incentives are not always clear. While some customers find the IPSO preferable from economic reasons other customers have the opposite recognition.
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| 6. |
- Sayardoust, Shariel, 1979
(författare)
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The effect of tobacco exposure on bone healing and the osseointegrationof dental implants
- 2017
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Background: The mechanisms behind the impact of smoking on osseointegration are not fully understood. Aim: To correlate the clinical and molecular aspects of osseointegration in smokers compared with non-smokers. Methodology: Study I: In a retrospective cohort study of smokers and nonsmokers, the 5-years implant survival and marginal bone loss (MBL) of machined and oxidized implants, were assessed. Studies II and III: In a prospective controlled study, smokers (n=16) and non-smokers (n=16) received machined, oxidized and laser-modified implants. Pain scores, implant stability quotient (ISQ) and gene expression of peri-implant crevicular fluid (PICF) and baseline bone biopsies were analyzed during 0-90d. Clinical assessments and radiology were performed at 90d. Study IV: Smokers (n=24) and non-smokers (n=24), each received two mini-implants with machined and oxidized surfaces. The gene expression of selected factors was analyzed in implant-adherent cells and surrounding bone after 1d, 7d and 28d. Results: Study I: Overall implant survival rate was lower in smokers. In smokers, machined implants failed more frequently than oxidized implants. Mean MBL at 5 years was higher at machined implants in smokers vs. non-smokers. Studies II and III: A higher ISQ was found in smokers compared to nonsmokers. Greater MBL was found in smokers than non-smokers, particularly at the machined implant. At 90d in smokers, the PICF around machined implants revealed a higher expression of pro-inflammatory cytokine, IL-6, and a lower expression of osteocalcin compared with the surface-modified implants. Multivariate regression revealed that smoking, BoP, IL-6 expression in PICF at 90d and HIF-1α baseline expression are predictors for MBL at 90d. Study IV: Cells adherent to machined implants revealed higher expression of pro-inflammatory cytokine, TNF-α. After 7d and 28d, the expression of bone formation gene, ALP, was higher at oxidized implants. Smoking was associated with initial inhibition of bone remodeling (CTR) and coupling (OPG and RANKL) genes in cells on machined implants. Conclusions: Smoking is associated with higher MBL during the early healing phase (0- 90d), and an increased failure rate and MBL in the long-term (5 years). Whereas the machined implants were associated with a dysregulated inflammation, osteogenesis and remodeling, an increased MBL and failure rate in smokers, the oxidized implants appear to favor osseointegration by mitigating the negative effects of smoking. It is concluded that the local effects of smoking on osseointegration are modulated by host factors and implant surface properties.
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| 10. |
- Kiehn, O
(författare)
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Locomotor circuits in the mammalian spinal cord
- 2006
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Ingår i: Annual review of neuroscience. - : Annual Reviews. - 0147-006X .- 1545-4126. ; 29, s. 279-306
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Tidskriftsartikel (refereegranskat)abstract
- Intrinsic spinal networks, known as central pattern generators (CPGs), control the timing and pattern of the muscle activity underlying locomotion in mammals. This review discusses new advances in understanding the mammalian CPGs with a focus on experiments that address the overall network structure as well as the identification of CPG neurons. I address the identification of excitatory CPG neurons and their role in rhythm generation, the organization of flexor-extensor networks, and the diverse role of commissural interneurons in coordinating left-right movements. Molecular and genetic approaches that have the potential to elucidate the function of populations of CPG interneurons are also discussed.
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