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- Baptista, Marisa A. P., et al.
(författare)
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Deletion of Wiskott-Aldrich syndrome protein triggers Rac2 activity and increased cross-presentation by dendritic cells
- 2016
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Ingår i: Nature Communications. - : Springer Science and Business Media LLC. - 2041-1723. ; 7
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Tidskriftsartikel (refereegranskat)abstract
- Wiskott-Aldrich syndrome (WAS) is caused by loss-of-function mutations in the WASp gene. Decreased cellular responses in WASp-deficient cells have been interpreted to mean that WASp directly regulates these responses in WASp-sufficient cells. Here, we identify an exception to this concept and show that WASp-deficient dendritic cells have increased activation of Rac2 that support cross-presentation to CD8(+) T cells. Using two different skin pathology models, WASp-deficient mice show an accumulation of dendritic cells in the skin and increased expansion of IFN gamma-producing CD8(+) T cells in the draining lymph node and spleen. Specific deletion of WASp in dendritic cells leads to marked expansion of CD8(+) T cells at the expense of CD4(+) T cells. WASp-deficient dendritic cells induce increased cross-presentation to CD8(+) T cells by activating Rac2 that maintains a near neutral pH of phagosomes. Our data reveals an intricate balance between activation of WASp and Rac2 signalling pathways in dendritic cells.
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- Bolelli, G., et al.
(författare)
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Sliding and abrasive wear behaviour of HVOF- and HVAF-sprayed Cr3C2-NiCr hardmetal coatings
- 2016
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Ingår i: Wear. - : Elsevier BV. - 0043-1648 .- 1873-2577. ; 358-359, s. 32-50
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Tidskriftsartikel (refereegranskat)abstract
- This paper provides a comprehensive characterisation of HVOF- and HVAF-sprayed Cr3C2–25 wt.% NiCr hardmetal coatings. One commercial powder composition with two different particle size distributions was processed using five HVOF and HVAF thermal spray systems.All coatings contain less Cr3C2 than the feedstock powder, possibly due to the rebound of some Cr3C2-rich particles during high-velocity impact onto the substrate.Dry sand-rubber wheel abrasive wear testing causes both grooving and pull-out of splat fragments. Mass losses depend on inter- and intra-lamellar cohesion, being higher (≥70 mg after a wear distance of 5904 m) for the coatings deposited with the coarser feedstock powder or with one type of HVAF torch.Sliding wear at room temperature against alumina involves shallower abrasive grooving, small-scale delamination and carbide pull-outs, and it is controlled by intra-lamellar cohesion. The coatings obtained from the fine feedstock powder exhibit the lowest wear rates (≈5x10−6 mm3/(Nm)). At 400 °C, abrasive grooving dominates the sliding wear behaviour; wear rates increase by one order of magnitude but friction coefficients decrease from ≈0.7 to ≈0.5. The thermal expansion coefficient of the coatings (11.08x10−6 °C−1 in the 30–400 °C range) is sufficiently close to that of the steel substrate (14.23x10−6 °C−1) to avoid macro-cracking
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- Bolelli, G., et al.
(författare)
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Tribology of HVOF- and HVAF-sprayed WC-10Co4Cr hardmetal coatings : A comparative assessment
- 2015
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Ingår i: Surface and Coatings Technology. - : Elsevier. - 0257-8972. ; 265, s. 125-144
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Tidskriftsartikel (refereegranskat)abstract
- his paper provides a comprehensive assessment of the sliding and abrasive wear behaviour of WC–10Co4Cr hardmetal coatings, representative of the existing state-of-the-art. A commercial feedstock powder with two different particle size distributions was sprayed onto carbon steel substrates using two HVOF and two HVAF spray processes.Mild wear rates of < 10-7 mm3/(Nm) and friction coefficients of ≈ 0.5 were obtained for all samples in ball-on-disk sliding wear tests at room temperature against Al2O3 counterparts. WC–10Co4Cr coatings definitely outperform a reference electrolytic hard chromium coating under these test conditions. Their wear mechanisms include extrusion and removal of the binder matrix, with the formation of a wavy surface morphology, and brittle cracking. The balance of such phenomena is closely related to intra-lamellar features, and rather independent of those properties (e.g. indentation fracture toughness, elastic modulus) which mainly reflect large-scale inter-lamellar cohesion, as quantitatively confirmed by a principal component analysis. Intra-lamellar dissolution of WC into the matrix indeed increases the incidence of brittle cracking, resulting in slightly higher wear rates. At 400 °C, some of the hardmetal coatings fail because of the superposition between tensile residual stresses and thermal expansion mismatch stresses (due to the difference between the thermal expansion coefficients of the steel substrate and of the hardmetal coating). Those which do not fail, on account of lower residual stresses, exhibit higher wear rates than at room temperature, due to oxidation of the WC grains.The resistance of the coatings against abrasive wear, assessed by dry sand–rubber wheel testing, is related to inter-lamellar cohesion, as proven by a principal component analysis of the collected dataset. Therefore, coatings deposited from coarse feedstock powders suffer higher wear loss than those obtained from fine powders, as brittle inter-lamellar detachment is caused by their weaker interparticle cohesion, witnessed by their systematically lower fracture toughness as well.
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- Hemphälä, H., et al.
(författare)
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Towards better lighting recommendations for open surgery
- 2020
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Ingår i: Lighting Research and Technology. - : SAGE Publications. - 1477-1535 .- 1477-0938. ; 52:7, s. 856-882
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Tidskriftsartikel (refereegranskat)abstract
- This study assesses the lighting requirements for operating theatres and the lighting conditions in a specific test case and proposes alternate ways of achieving a favourable visual environment. The hypothesis was that an increased illuminance level from general lighting and lower luminance contrasts between the essential task areas affect perceived lighting quality, visual ability and performance, as well as tiredness of medical staff performing surgical work. The investigation consisted of three parts: a laboratory study, followed by a field study and concluding with a retrospective study. In the laboratory study, each medical staff subject was exposed to four lighting scenarios with three illuminances from the operating light (12 lighting conditions), with no patients present. In the field and the retrospective study, the existing lighting scenario was compared to the highest-rated test lighting scenario (with illuminances more than double). The field study and the retrospective study took place with medical staff working under either the test general lighting condition or the existing general lighting condition. Increased illuminance from the general lighting and a higher correlated colour temperature did not improve the operating staff’s visual ability. However, medical staff rated the change in lighting quality resulting from the increased general illuminance as an improvement in the work environment, both in the laboratory study and in the field study. Medical staff subjects using the operating theatre rated both perceived visual ability and lighting quality higher under the test lighting scenario. Tiredness was also rated lower under that test scenario. Based on the results from this study, general lighting levels of 2000 lx in the periphery of the operating room, 4000 lx surrounding the operating table and 5500 lx on the operating table are recommended by the authors. With reference to the selections made by the surgeons for the illuminance in the operating cavity, it is suggested that the central beam illuminance from the surgical luminaires be between 50,000 lx and 100,000 lx.
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- Ottosson, H, et al.
(författare)
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Potent Inducers of Endogenous Antimicrobial Peptides for Host Directed Therapy of Infections
- 2016
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Ingår i: Scientific reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 6, s. 36692-
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Tidskriftsartikel (refereegranskat)abstract
- A new concept for treatment of infections is induction of our own antimicrobial peptides and the presented novel class of inducer, aroylated phenylenediamines (APDs), gives up to 20 to 30-fold induction of the human antimicrobial peptide LL-37, in vitro. In addition, oral administration of an APD in a rabbit model of Shigellosis resulted in recovery from the infection in a few days implying that APD’s are promising candidates for treatment of infections.
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- Aronsson, K, et al.
(författare)
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Synergonomi och ögonbesvär hos personal på ögonsjukhus.
- 2012
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Ögonläkare, ögonsjuksköterskor, optiker och annan personal på ögonsjukhus arbetar ofta med synkrävande arbetsuppgifter i dämpad belysning eller helt utan allmänbelysning. Inför den planerade byggnationen av ett nytt ögonsjukhus i Stockholm ca år 2018 gjordes en enkätstudie för att kartlägga ögonbesvär och trötthet hos personalen på S:t Eriks Ögonsjukhus. Studien som är ett multidisciplinärt samarbetsprojekt mellan S:t Erik, Karolinska Institutet och Kungliga Tekniska Högskolan, syftar till att optimera belysning, dagsljusinsläpp och ljusmiljö vid det nya ögonsjukhuset.Totalt 265 anställda på S:t Eriks Ögonsjukhus samt 60 röntgenläkare och 45 barnläkare, varav de senare två utgjorde jämförelsegrupper, inviterades till studien. Enkäten som distribuerades baserades på synergonomienkäter av Knave och Hemphälä och bestod av 31 validerade frågor om subjektiva ögonbesvär, nuvarande belysning, tillgång till dagsljus och välbefinnande. Ögonbesvären räknades om till ett gruppmedelvärde (ögonbesvärsindex) med avseende på svårighetsgrad och frekvens. Studien är godkänd av Etikprövningsnämnden. Nittiosex av 265 (33%) anställda på S:t Eriks Ögonsjukhus hade t o m juni 2012 besvarat enkäten tillsammans med 23 röntgenläkare (38%) och 14 barnläkare (31%). Ögonbesvär som torrhets- och gruskänsla var vanligt förekommande hos alla yrkesgrupper på ögonsjukhuset och generellt vanligare hos kvinnor. Då samtliga grupper jämfördes med avseende på ögonbesvärsindex var skillnaden mellan män och kvinnor statistiskt säkerställd (p<0,05). Röntgenläkarna rapporterade högst ögonbesvärsindex och barnläkarna lägst, skillnaden mellan dessa yrkesgrupper var signifikant (p<0,05). Ögonpersonal och röntgenläkare som rapporterade att de ofta arbetade i mörker, associerade detta med ökad trötthet i högre grad än med barnläkarna (p<0,05).Ögonbesvär var vanliga hos ögonpersonalen inkluderade i studien. Den grupp som arbetade mest i mörker hade mer ögonbesvär än den grupp som arbetade minst i mörker. Kvinnor hade mer ögonbesvär än män. Arbete i mörker ökade den subjektiva känslan av trötthet . Optimala ljusförhållanden och bra synergonomi bör ges hög prioritet vid planering av ett nytt ögonsjukhus.
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- Aronsson, K, et al.
(författare)
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Visual ergonomics and eye strain in eye careprofessionals
- 2012
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Ingår i: NES2012 Proceedings. - 9789163711503
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Eye care professionals spend many hours a day in darkness performing visually demanding tasks. A new eye hospital will be built in Stockholm 2018. The current lighting, logistics, and working conditions are analysed in a multidisciplinary project aiming to optimise settings in the new hospital. The main purpose of the present project was to study visual ergonomics and current eye strain in employees at an eye hospital. Ninety-six employees answered a validated questionnaire regarding their experiences of light, visual ergonomics and eye strain problems. Twenty-three radiologists and 14 paediatricians at a university hospital were used as comparison groups. Eye strain was common in all departments at the hospital but was significantly more common only among radiologists compared to paediatricians. Overall, women experienced significantly more eye strain than men.
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