| 1. |
- Callegari, Riccardo, et al.
(author)
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Early Neoproterozoic magmatism and Caledonian metamorphism recorded by the Mårma terrane, Seve Nappe Complex, northern Swedish Caledonides
- 2023
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In: Journal of the Geological Society. - : Geological Society of London. - 0016-7649 .- 2041-479X. ; 180:5
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Journal article (peer-reviewed)abstract
- Petrology, geochronology and bulk-rock chemistry are combined to investigate the early Neoproterozoic magmatismand Cambrian–Ordovician metamorphism in the northern Swedish Caledonides. This work includes several lithologies of theMårma terrane in the Seve Nappe Complex exposed in the Kebnekaise region. U–Pb zircon geochronology yielded crystallizationages of 835 ± 8 Ma for a mylonitic orthogneiss, 864 ± 3 Ma for the Vistas Granite and 840 ± 7 Ma for an intruded granitic dyke,whereas a gabbro and a granodiorite intrusion gave U–Pb zircon crystallization ages of 856 ± 3 Ma and 850 ± 1 Ma, respectively.U–Pb monazite dating of the mylonitic orthogneiss gave an upper intercept age of 841 ± 7 Ma and a lower intercept age of443 ± 20 Ma. Pressure–temperature estimates derived for the mylonitic orthogneiss reveal metamorphic peak-pressure and peaktemperatureof 10.5–11.75 kbar and 550–610°C and 7.4–8.1 kbar at 615–675°C, respectively.Metamorphic pressure–temperatureestimates for the Vistas Granite yield 6.5–7.5 kbar at 600–625°C. Whole-rock chemistry coupled with U–Pb geochronologyindicates that bimodal magmatism was related to attempted rifting of Rodinia between 870 and 840 Ma.
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| 2. |
- Nilsson, Patrik, et al.
(author)
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Design of experiments to investigate multi-additive cellulose nanocrystal films
- 2022
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In: Frontiers in Molecular Biosciences. - : Frontiers Media S.A.. - 2296-889X. ; 9
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Journal article (peer-reviewed)abstract
- Cellulose nanocrystal (CNC) suspensions can self-assemble into chiral nematic films upon the slow evaporation of water. These films are brittle, as indicated by their fracturing instead of plastically deforming once they are fully elastically deformed. This aspect can be mediated to some extent by plasticizing additives, such as glucose and glycerol, however, few reports consider more than one additive at a time or address the influence of additive content on the homogeneity of the self-assembled structure. In this work, design of experiments (DoE) was used to empirically model complex film compositions, attempting to relate additive concentrations in dilute suspension to film properties, and to understand whether outcome specific predictions are possible using this approach. We demonstrate that DoE can be used to predict film properties in multi-additive systems, without consideration given to the different phenomena that occur along the drying process or to the nature of the additives. Additionally, a homogeneity metric is introduced in relation to chiral nematic organization in CNC films, with most of the additive-containing compositions in this work found to reduce the homogeneity of the self-assembly relative to pure CNC films. Copyright © 2022 Nilsson, Engström, Kaschuk, Vapaavuori, Larsson and Abitbol.
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| 3. |
- Stockfelt, Leo, 1981, et al.
(author)
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A controlled chamber study of effects of exposure to diesel exhaust particles and noise on heart rate variability and endothelial function
- 2022
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In: Inhalation Toxicology. - : Taylor and Francis Ltd.. - 0895-8378 .- 1091-7691. ; 34:5-6, s. 159-170
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Journal article (peer-reviewed)abstract
- Background: Adverse cardiovascular effects are associated with both diesel exhaust and road traffic noise, but these exposures are hard to disentangle epidemiologically. We used an experimental setup to evaluate the impact of diesel exhaust particles and traffic noise, alone and combined, on intermediary outcomes related to the autonomic nervous system and increased cardiovascular risk. Methods: In a controlled chamber 18 healthy adults were exposed to four scenarios in a randomized cross-over fashion. Each exposure scenario consisted of either filtered (clean) air or diesel engine exhaust (particle mass concentrations around 300 µg/m3), and either low (46 dB(A)) or high (75 dB(A)) levels of traffic noise for 3 h at rest. ECG was recorded for 10-min periods before and during each exposure type, and frequency-domain heart rate variability (HRV) computed. Endothelial dysfunction and arterial stiffness were assessed after each exposure using EndoPAT 2000. Results: Compared to control exposure, HRV in the high frequency band decreased during exposure to diesel exhaust, both alone and combined with noise, but not during noise exposure only. These differences were more pronounced in women. We observed no synergistic effects of combined exposure, and no significant differences between exposure scenarios for other HRV indices, endothelial function or arterial stiffness. Conclusion: Three-hour exposure to diesel exhaust, but not noise, was associated with decreased HRV in the high frequency band. This indicates activation of irritant receptor-mediated autonomic reflexes, a possible mechanism for the cardiovascular risks of diesel exposure. There was no effect on endothelial dysfunction or arterial stiffness after exposure. © 2022 The Author(s).
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| 4. |
- Carroll, Christopher, et al.
(author)
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Hypoxia Generated by Avian Embryo Growth Induces the HIF-α Response and Critical Vascularization
- 2021
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In: Frontiers in Ecology and Evolution. - : Frontiers Media SA. - 2296-701X. ; 9, s. 1-15
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Journal article (peer-reviewed)abstract
- Cancer research has transformed our view on cellular mechanisms for oxygen sensing. It has been documented that these mechanisms are important for maintaining animal tissues and life in environments where oxygen (O2) concentrations fluctuate. In adult animals, oxygen sensing is governed by the Hypoxia Inducible Factors (HIFs) that are stabilized at low oxygen concentrations (hypoxia). However, the importance of hypoxia itself during development and for the onset of HIF-driven oxygen sensing remains poorly explored. Cellular responses to hypoxia associates with cell immaturity (stemness) and proper tissue and organ development. During mammalian development, the initial uterine environment is hypoxic. The oxygenation status during avian embryogenesis is more complex since O2 continuously equilibrates across the porous eggshell. Here, we investigate HIF dynamics and use microelectrodes to determine O2 concentrations within the egg and the embryo during the first four days of development. To determine the increased O2 consumption rates, we also obtain the O2 transport coefficient (DO2) of eggshell and associated inner and outer shell membranes, both directly (using microelectrodes in ovo for the first time) and indirectly (using water evaporation at 37.5°C for the first time). Our results demonstrate a distinct hypoxic phase (<5% O2) between day 1 and 2, concurring with the onset of HIF-α expression. This phase of hypoxia is demonstrably necessary for proper vascularization and survival. Our indirectly determined DO2 values are about 30% higher than those determined directly. A comparison with previously reported values indicates that this discrepancy may be real, reflecting that water vapor and O2 may be transported through the eggshell at different rates. Based on our obtained DO2 values, we demonstrate that increased O2 consumption of the growing embryo appears to generate the phase of hypoxia, which is also facilitated by the initially small gas cell and low membrane permeability. We infer that the phase of in ovo hypoxia facilitates correct avian development. These results support the view that hypoxic conditions, in which the animal clade evolved, remain functionally important during animal development. The study highlights that insights from the cancer field pertaining to the cellular capacities by which both somatic and cancer cells register and respond to fluctuations in O2 concentrations can broadly inform our exploration of animal development and success.
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| 5. |
- Omelekhina, Yuliya, et al.
(author)
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Cooking and electronic cigarettes leading to large differences between indoor and outdoor particle composition and concentration measured by aerosol mass spectrometry
- 2020
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In: Environmental Sciences: Processes and Impacts. - : Royal Society of Chemistry (RSC). - 2050-7895 .- 2050-7887. ; 22:6, s. 1382-1396
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Journal article (peer-reviewed)abstract
- We spend about two thirds of our time in private homes where airborne particles of indoor and outdoor origins are present. The negative health effects of exposure to outdoor particles are known. The characteristics of indoor airborne particles, though, are not well understood. This study assesses the differences in chemical composition of PM1 (<1 μm) inside and outside of an occupied Swedish residence in real time with a High-Resolution Time-of-Flight Aerosol Mass Spectrometer (HR-ToF-AMS) and an Aethalometer. The chemical composition and concentration of particles indoors showed large differences compared to outdoors. The average indoor concentration was 15 μg m-3 and was higher than the outdoor 7 μg m-3. Organics dominated indoor particle composition (86% of the total mass) and originated from indoor sources (cooking, e-cigarette vaping). The average indoor to outdoor ratios were 5.5 for organic matter, 1.0 for black carbon, 0.6 for sulphate, 0.1 for nitrate, 0.2 for ammonium and 0.2 for chloride. The occupancy time accounted for 97% of the total measured period. Four factors were identified in the source apportionment of organic particle fraction by applying positive matrix factorization (PMF): two cooking factors, one e-cigarette factor and one outdoor contribution (OOA) organic factor penetrated from outside.
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| 6. |
- Kristensson, Adam, et al.
(author)
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Metaller i luftburna partiklar i Landskrona 2017
- 2019
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Reports (other academic/artistic)abstract
- Mellan 16 februari och 22 mars 2017 genomfördes 24 mätningar av finfraktionen (PM2.5) och grovfraktionen (PM10 – PM2.5) av grundämnen i luftburna partiklar på mätstationerna i Stadshuset och Lundåkrahamnen i Landskrona. Detta gjordes som ett led i att kontrollera luftkvaliten i Landskrona stad, särskilt med tanke på industrierna i Landskrona, som tidigare har givit höga halter av framförallt metaller i luften för åren 1977, 1988, 2003, och 2008. Bägge mätstationerna representerar urbana bakgrundsstationer, där Stadshusets mätningar är i trafikmiljö, medan Lundåkrahamnens mätningar är i industriområde.Flertalet ämnen kunde detekteras med PIXE-analysmetoden; Al, Si, P, S, Cl, K, Ca, Ti, Cr, Mn, Fe, Ni, Cu, Zn, Br, Sr, Pb. V och As låg mestadels under detektionsgränsen. Ga, Ge, Se, Rb, Y, Zr, Pd, Cd, och Sn var aldrig detekterbara.För grovfraktionen både vid Stadshuset och Lundåkrahamnen har mätningar under år 2008 generellt gett de lägsta partikelhlaterna. Förutom detta år har det rent generellt varit en nedåtgående trend för halterna för följande ämnen sedan 1977; K, Ca, Ti, Mn, Fe, Ni, Zn, och Pb. Nästan oförändrade halter har observerats för Al, Si, S, Cu, och Br. Halterna av Cl och Cr har rent av gått upp. Det bör dock nämnas att Cl kommer från den naturliga källan havssprej, varför halterna av Cl och andra naturliga ämnen mer beror på meteorologiska förutsättningar än minskningar i mänskliga utsläpp. För finfraktionen har vi nedåtgående trend sedan 1977 för; S, K, Ca, Ti, Mn, Fe, Ni, Cu, Zn, Br, och Pb. Oförändrade halter för Cr, och uppåtgående trend för Cl.P mättes för första gången både i grov- och finfraktion. Detta ämne kan till exempel komma från jordstoftpartiklar, samt från havet (övergödning). Men, ingen vidare korrelation kunde skönjas med jordstoftpartiklar och havssprejpartiklar. Ämnet har betydelse för bördiga jordar och övergödning, varför det är viktigt att fortsätta mäta detta ämne.Käll/receptor-modellering har utförts för att beräkna källtilldelningen. PMF-modellen kördes med en lätt polarisering av källorna (FPEAK-paramter = 0.5) och för grovfraktion och finfraktion för sig, och de två stationerna var och en för sig. Det gjordes alltså 4 olika PMF-körningar.Resultaten visade att vi i princip har 7 olika källor för partiklar och grundämneselement i Landskrona;1. Havssprej2. Jordstoftpartiklar3. Pb-källa4. Fe/Zn-källa5. Cr/Ni-källa6. Cu/Zn-källa7. Åldrad källaHavssprej både i Stadshuset och Lundåkrahamnen utgörs av grova partiklar med Cl, Br som främsta ämnen. Även finfraktionen innehåller en hög halt Cl och Br, vilket förmodligen beror på att även finfraktionen innehåller en relativt hög andel grova partiklar. Högsta halterna är förknippade med havsluft västerifrån.Jorstoftpartiklar karakteriseras av elementen Si, K, Ca, Ti, och Fe, vilka är typiska för jordskorpan. Framförallt grova partiklar ger höga halter av dessa ämnen, men även finfraktionen kan innehålla en andel grova partiklar liksom havssprejkällan.Pb-källan är förknippad med vindar från Boliden-Bergsoe-fabriken, vilket den även har varit för föregående mätningar, både vid Stadshuset och Lundåkrahamnen, såväl i fin- som i grovfraktionen.Fe/Zn-källan är vid några tillfällen associerad med vindar från hamnområdet eller Scandust, för både grov- och finfraktionen i Stadshuset och Lundåkrahamnen. Det går dock inte att härleda denna källa till specifik aktivitet i detta område i Landskrona. En del av Fe/Zn-källan samvarierar med jordsoftkällan, vilket bevisar att en del av Fe och Zn kommer från jordstoft. Detta är väntat eftersom jordskorpan även innehåller dessa element.Liknande resonemang gäller för Cr/Ni-källan. Vi kan dessutom inte utesluta att Cr/Ni i finfraktionen dessutom kommer från långdistanstransport av fossila förbränningspartiklar, eftersom fossil olja ofta innehåller Cr och Ni.Återigen gäller liknande resonemang för Cu/Zn-källan. Dessutom är det möjligt att en del Cu/Zn-damm och fina partiklar möjligen härstammar från färgborttagning från småbåtar och målning.Den sista källan är en långdistanstransporterad källa innehållandes S, framförallt i finfraktionen. Denna kommer från kondensation av svaveldioxid eller svavelsyra under långdistanstransport under flera timmar eller dygn (sekundär källa), eller direkt under förbränning av fossila bränslen (primär källa). Man kan förvänta sig att denna källa har minskat i och med regleringen av sulfatinnehållet i sjöfartsbränslet sedan 2015 i Östersjön och Nordsjön, eller generellt bättre rening av S från kolkraftverk eller andra industrier med förbränningsprocesser sedan konventionen om gränsöverskridande luftföroreningar (CLRTAP) kom igång ordentligt på 80-talet. En svag trend är synlig. Å andra sidan kan variationer i S bero på variationer i meteorologiska förhållanden, och inte enbart på grund av utsläppsminskningar.
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| 7. |
- Omelekhina, Yuliya, et al.
(author)
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Indoor-to-outdoor ratios of ultrafine particles in Swedish residences
- 2019
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Conference paper (other academic/artistic)abstract
- A number of health effects have been linked to exposure to airborne particles, however the consequences of exposure to ultrafine particles is largely unknown. Ultrafine particles can be emitted from different indoor activities or be of the outdoor origin. This is further complicated by the fact that we are spending majority of the time indoors. The aim of this work was to assess the influence of renovations on indoor-to-outdoor (I/O) ratios of ultrafine particles (UFP) in 6 occupied Swedish residences. Simultaneous indoor and outdoor measurements were performed in 6 residences for seven consecutive days in urban area in southern Sweden. The apartments were mechanically ventilated and had volumes between 115-218 m3. The renovation activities included adjusting air exchange rates (AER) to meet Swedish standards (0.5 AER h-1) and installation of the new kitchen extraction fans. NanoTracers (Oxility Aerasense) were used to measure particle number concentrations and mean particle diameters (10 - 300 nm). Based on the averages of particle number concentrations (PNC) during occupancy period, indoor-to-outdoor ratios (I/O) were calculated for each home. AER have been increased in the apartments during renovations to 0.4-0.7 h-1 in comparison to values before the renovation 0.2-0.4 h-1. After renovation I/O ratios of PNC during occupancy periods varied between 0.2-3.8 and were lower in comparison to the values before renovations 1.0-11.9. This could indicate increased efficiency of particles removal after renovation but also can be influenced by lower amount of performed activities by occupants, which were 2-3 times lower after in comparison to before. Results have shown the positive changes of the renovation processes on AER and particle removal. Nevertheless, the frequency and type of indoor activities performed by residents at home influence the indoor concentrations. The Swedish Research Council FORMAS and the Swedish Energy Agency financed the project.
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| 8. |
- Andréasson, Per Gunnar, et al.
(author)
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Seve terranes of the Kebnekaise Mts., Swedish Caledonides, and their amalgamation, accretion and affinity
- 2018
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In: GFF. - : Informa UK Limited. - 1103-5897 .- 2000-0863. ; 140:3, s. 264-291
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Journal article (peer-reviewed)abstract
- A major allochthon of the Scandinavian Caledonides, the Seve belt has traditionally been considered to be derived from the rifted margin and continent-ocean transition (COT) of Baltica. However, geochronological results obtained from its inferred northern equivalent, the Kalak Nappe Complex (KNC), have been taken to indicate an exotic affinity of this complex and of also Seve terranes, an interpretation adopted in recent palaeogeographic models. In the Kebnekaise Mts., the COT is represented by the Kebnekaise terrane composed of amphibolitized dykes of gabbro and dolerite of depleted magma source and rare felsic and ultramafic rocks. Coronitic dolerite and gabbro with abundant rutile suggest high pressures before or during amalgamation with the underlying Mårma terrane, composed of quartzofeldspathic gneisses intruded by mafic and granitic rocks, the latter including a previously dated c. 845 Ma-old granite. The granite mingled with mildly alkaline dolerites chemically similar to transitional basalts of continental rifts. Following emplacement at shallow (andalusite stability) crustal levels, the igneous complex and host rocks underwent extensive deformation, metamorphism within the sillimanite-kyanite stability field and local migmatization. The Kebnekaise and Mårma terranes amalgamated in early Ordovician as indicated by the U-Pb age of 487±7 Ma obtained from titanite fabrics of deformed granite in thrust vicinity, and by 40Ar-39Ar results. The pressure increase in both terranes suggests that amalgamation occurred during initial subduction and imbrication. Correlation of the Mårma terrane with the KNC is discussed. Results obtained in this study give no reason to ascribe an exotic affinity to the Seve terranes of the Kebnekaise Mts.
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| 9. |
- Bothén, Simon, et al.
(author)
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An analysis and comparative user study on interactions in mobile virtual reality games
- 2018
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In: FDG '18: Proceedings of the 13th International Conference on the Foundations of Digital Games. - New York, NY, USA : Association for Computing Machinery (ACM). - 9781450365710
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Conference paper (peer-reviewed)abstract
- Mobile Virtual Reality (MVR) makes Virtual Reality games more accessible to a broader audience. Interaction design guidelines and best practices for MVR experiences are available for developers. In this paper, we specifically explore interactions in MVR games, a particular subset of MVR experiences that is becoming popular. A set of MVR games is analyzed with a special focus on head gaze, categorizing and isolating their mechanics implemented with this common MVR technique. This analysis is the basis of a test application in the MVR interactions are implemented and later compared to a traditional game pad controller in three different challenges. A comparative user study has been carried out from the perspective of both gamers and non-gamers facing these challenges. Results show the preferences and performances of the players using all the interactions, highlighting an interesting generalized preference for MVR interactions over the traditional controller in some of the analyzed cases.
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| 10. |
- Nilsson, Patrik T., et al.
(author)
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Emissions into the air from bitumen and rubber bitumen - Implications for asphalt workers' exposure
- 2018
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In: Annals of Work Exposures and Health. - : Oxford University Press (OUP). - 2398-7308 .- 2398-7316. ; 62:7, s. 828-839
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Journal article (peer-reviewed)abstract
- The risk among asphalt workers of developing adverse health effects may increase due to their occupational exposure. One area of special concern arises when rubber granules are mixed into bitumen to enhance asphalt properties. This research characterizes and compares bitumen and rubber bitumen regarding the emissions of and workers' exposure to particulates, polycyclic aromatic hydrocarbons (PAHs) and benzothiazole. A laboratory and a field study were carried out. In the laboratory, two types of bitumen, one with and one without rubber, were heated up to two temperatures (140°C and 160°C). The concentrations and chemical compositions of the emissions were determined. In the field at asphalt work sites, both emissions and worker exposure measurements were performed. The methods applied included direct-reading sampling techniques next to the asphalt work area and personal sampling techniques on asphalt workers. The exposure measurements on asphalt workers for respirable dust, total dust, particle number and mass, and total PAH concentrations showed similar concentrations when both standard and rubber bitumen were used. The asphalt-surfacing machine operators were the workers with the highest observed exposure followed by the screed operators and roller drivers. Both laboratory and field measurements showed higher concentrations of benzothiazole when rubber bitumen was used, up to 7.5 times higher in the laboratory. The levels of naphthalene, benzo(a)pyrene, and total particles were lower for both types compared with the Swedish occupational exposure limits, 8-h time weighted average concentrations. Benzo(a)pyrene exceeded however the health-based guideline value given by the WHO for both types of bitumen. The study concludes that several air pollutants such as benzothiazole and PAHs are emitted into the air during asphalt work, but it is not evident if exposure to rubber bitumen possesses a higher risk than exposure to standard bitumen in terms of asphalt worker exposure.
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