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  • 151. Al-Behadili, Ali
    et al.
    Uhler, Jay P.
    Berglund, Anna-Karin
    Peter, Bradley
    Doimo, Mara
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Reyes, Aurelio
    Wanrooij, Sjoerd
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Zeviani, Massimo
    Falkenberg, Maria
    A two-nuclease pathway involving RNase H1 is required for primer removal at human mitochondrial OriL2018In: Nucleic Acids Research, ISSN 0305-1048, E-ISSN 1362-4962, Vol. 46, no 18, p. 9471-9483Article in journal (Refereed)
    Abstract [en]

    The role of Ribonuclease H1 (RNase H1) during primer removal and ligation at the mitochondrial origin of light-strand DNA synthesis (OriL) is a key, yet poorly understood, step in mitochondrial DNA maintenance. Here, we reconstitute the replication cycle of L-strand synthesis in vitro using recombinant mitochondrial proteins and model OriL substrates. The process begins with initiation of DNA replication at OriL and ends with primer removal and ligation. We find that RNase H1 partially removes the primer, leaving behind the last one to three ribonucleotides. These 5′-end ribonucleotides disturb ligation, a conclusion which is supported by analysis of RNase H1-deficient patient cells. A second nuclease is therefore required to remove the last ribonucleotides and we demonstrate that Flap endonuclease 1 (FEN1) can execute this function in vitro. Removal of RNA primers at OriL thus depends on a two-nuclease model, which in addition to RNase H1 requires FEN1 or a FEN1-like activity. These findings define the role of RNase H1 at OriL and help to explain the pathogenic consequences of disease causing mutations in RNase H1.

  • 152.
    Albers, Michael F
    et al.
    Department of Chemical Biology, Max Planck Institute for Molecular Physiology.
    Hedberg, Christian
    Amino acid building blocks for Fmoc solid-phase synthesis of peptides phosphocholinated at serine, threonine, and tyrosine2013In: Journal of Organic Chemistry, ISSN 0022-3263, E-ISSN 1520-6904, Vol. 78, no 6, p. 2715-2719Article in journal (Refereed)
    Abstract [en]

    Phosphocholination of eukaryotic host cell proteins has recently been identified as a novel post-translational modification important for bacterial pathogenesis. Here, we describe the first straightforward synthetic strategy for peptides containing phosphocholinated serine, threonine, or tyrosine residues using preformed functional amino acid building blocks, fully compatible with standard Fmoc solid-phase peptide synthesis.

  • 153.
    Albers, Michael F
    et al.
    Department of Chemical Biology, Max-Planck Institute of Molecular Physiology.
    van Vliet, Bart
    Hedberg, Christian
    Amino acid building blocks for efficient Fmoc solid-phase synthesis of peptides adenylylated at serine or threonine2011In: Organic Letters, ISSN 1523-7060, E-ISSN 1523-7052, Vol. 13, no 22, p. 6014-6017Article in journal (Refereed)
    Abstract [en]

    The first straightforward building block based (non-interassembly) synthesis of peptides containing adenylylated serine and threonine residues is described. Key features include final global acidolytic protective group removal as well as full compatibility with standard Fmoc solid-phase peptide synthesis (SPPS). The described Thr-AMP SPPS-building block has been employed in the synthesis of the Thr-adenylylated sequence of human GTPase CDC42 (Ac-SEYVP-T(AMP)-VFDNYGC-NH(2)). Further, we demonstrate proof-of-concept for the synthesis of an Ser-adenylylated peptide (Ac-GSGA-S(AMP)-AGSGC-NH(2)) from the corresponding adenylylated serine building block.

  • 154.
    Albers, Michael Franz
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Synthesis and investigation of bacterial effector molecules2016Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    During infections, bacterial microorganisms initiate profound interactions with mammalian host cells. Usually defense mechanisms of the host destroy intruding bacteria in rapid manner. However, many bacterial pathogens have evolved in a way to avoid these mechanisms. By use of effector molecules, which can be small organic molecules or proteins with enzymatic activity, the host is manipulated on a molecular level. Effectors mediating post-translational modifications (PTMs) are employed by many pathogens to influence the biological activity of host proteins. In the presented thesis, two related PTMs are investigated in detail: Adenylylation, the covalent transfer of an adenosine monophosphate group from adenosine triphosphate onto proteins, and phosphocholination, the covalent transfer of a phosphocholine moiety onto proteins. Over the past years, enzymes mediating these modifications have been discovered in several pathogens, especially as a mechanism to influence the signaling of eukaryotic cells by adenylylating or phosphocholinating small GTPases. However, the development of reliable methods for the isolation and identification of adenylylated and phosphocholinated proteins remains a vehement challenge in this field of research. This thesis presents general procedures for the synthesis of peptides carrying adenylylated or phosphocholinated tyrosine, threonine and serine residues. From the resulting peptides, mono-selective polyclonal antibodies against adenylylated tyrosine and threonine have been raised. The antibodies were used as tools for proteomic research to isolate unknown substrates of adenylyl transferases from eukaryotic cells. Mass spectrometric fragmentation techniques have been investigated to ease the identification of adenylylated proteins. Furthermore, this work presents a new strategy to identify adenylylated proteins. Additionally, small effector molecules are involved in the regulation of infection mechanisms. In this work, the small molecule LAI-1 (Legionella autoinducer 1) from the pathogen Legionella pneumophila, the causative agent of the Legionnaire’s disease, was synthesised together with its amino-derivatives. LAI-1 showed are a clear pharmacological effect on the regulation of the life cycle of L. pneumophila, initiating transmissive traits like motility and virulence. Furthermore, LAI-1 was shown to have an effect on eukaryotic cells as well. Directed motility of the eukaryotic cells was significantly reduced and the cytoskeletal architecture was reorganised, probably by interfering with the small GTPase Cdc42.

  • 155.
    Albertsson, Jan
    Umeå University, Faculty of Science and Technology, Umeå Marine Sciences Centre (UMF).
    Biologisk inventering av havsbottnar kring Örefjärden, Snöan och Bonden: Marinbiologisk inventering och naturvärdesbedömning av planerat marint naturreservat2009Report (Other academic)
  • 156.
    Albertsson, Jan
    Umeå University, Faculty of Science and Technology, Umeå Marine Sciences Centre (UMF).
    Inventering och naturvärdesbedömning av fyra kustnära havsområden i Västerbotten - Tavasten, Ostnäs, Juviken/Lillhavet och Kinnbäcksfjärden2017Report (Other academic)
    Abstract [sv]

    En inventering och naturvärdesbedömning av fyra kustnära havsområden i Västerbottens län har genomförts. Inventeringen fokuserade på undervattensvegetation och består huvudsakligen av en visuell transektinventering genom video och dykning utförd av Umeå marina forskningscentrum 2007-2008. Kunskapsunderlaget har utökats genom att inkludera flera andra undersökningar. Totalt spänner underlaget över tidsperioden 1997-2012.

  • 157.
    Albertsson, Jan
    Umeå University, Faculty of Science and Technology, Umeå Marine Sciences Centre (UMF).
    Miljöövervakning i Gaviksfjärden, Västernorrlands län: sammanställning och resultatanalys2014Report (Other academic)
  • 158.
    Albertsson, Jan
    Umeå University, Faculty of Science and Technology, Umeå Marine Sciences Centre (UMF).
    Trophic interactions involving mysid shrimps (Mysidacea) in the near-bottom habitat in the Baltic Sea2004In: Aquatic Ecology, ISSN 1386-2588, E-ISSN 1573-5125, Vol. 38, no 3, p. 457-469Article in journal (Refereed)
    Abstract [en]

    In a six month mesocosm tank experiment, hypotheses were tested concerning the role of benthopelagic mysid shrimps (Mysidacea) in the near-bottom food web of the Bothnian Sea, in the northern Baltic Sea. The first hypothesis tested was that the mysids interact, through predation, with benthic deposit-feeding Monoporeia affinis amphipods. A second hypothesis tested was that the sediment type is important for the overwintering success of the mysids. Changes in abundance and mass were recorded for M. affinis and mysids when separate and when coexisting, in two sediment types differing in organic content (food level); soft muddy clay (rich) and fine sand (poor). Despite the fact that newborn M. affinis offspring, a plausible target for predation by mysids, were present in substantial numbers in the tanks, no consistent evidence for any interaction between these taxa was found. The biomass of mysids was slightly higher in the muddy clay than in the sand tanks, and the mechanism behind this substrate effect is discussed. A third hypothesis, that the mysids interact with near-bottom zooplankton, was investigated. The tanks were continually supplied with in situ near-bottom sea-water containing a seminatural assemblage of near-bottom plankton. As a result of mysid predation, tanks with mysids had lower abundance and biomass of cyclopoid copepods than tanks without mysids. Thus, the major interaction found was predation on near-bottom zooplankton by mysids and it is suggested that this interaction could potentially be an important food link, especially during periods with low food availability in the pelagic system.

  • 159.
    Albertsson, Jan
    Umeå University, Faculty of Science and Technology, Umeå Marine Sciences Centre (UMF).
    Undervattensvegetation i Holmöarnas naturreservat: Inventeringar och miljöövervakningar genomförda under åren 1997, 2004 och 20072008Report (Other academic)
  • 160.
    Albertsson, Jan
    Umeå University, Faculty of Science and Technology, Umeå Marine Sciences Centre (UMF).
    Uppföljning av naturtypen 1140 blottade ler- och sandbottnar i Bottenviken och Södra Östersjön: En pilotstudie2016Report (Other (popular science, discussion, etc.))
  • 161.
    Albertsson, Jan
    Umeå University, Faculty of Science and Technology, Umeå Marine Sciences Centre (UMF).
    Övervakning av makrovegetation i Bottniska viken: En utvärdering av pågående undersökningar och underlag för vidareutveckling2014Report (Other academic)
  • 162.
    Albertsson, Jan
    et al.
    Umeå University, Faculty of Science and Technology, Umeå Marine Sciences Centre (UMF).
    Leonardsson, K
    Deposit-feeding amphipods (Monoporeia affinis) reduce the recruitment of copepod nauplii from benthic resting eggs in the northern Baltic Sea2001In: Marine Biology, ISSN 0025-3162, E-ISSN 1432-1793, Vol. 138, no 4, p. 793-801Article in journal (Refereed)
    Abstract [en]

    We experimentally investigated the effect of different densities of the burrowing, deposit-feeding amphipod Monoporeia affinis on the recruitment of zooplankton from benthic resting eggs. Intact sediment cores with in situ density and species composition of zooplankton resting eggs and benthic fauna were collected in the northern Bothnian Sea, part of the Baltic Sea. We removed as many M, affinis as possible from the cores and then added different numbers of ill. affinis to the cores to generate a range of densities. The cores were exposed to different densities of M. affinis for either 3 or 40 days, after which the hatched zooplankton was registered. One subset of the cores were initially incubated under low temperature (2-3 degreesC, to prevent hatching) for 37 days (the resting phase), to allow for effects of M. affinis on unhatched resting eggs. These cores were then incubated under higher temperature (13 degreesC) for 3 days (the hatching phase), to induce hatching and allow for effects on hatching or hatched specimens. In a second subset of cores with the same time and temperature schedule, the M. affinis density was experimentally reduced at the start of the hatching phase, to evaluate the effect of M. affinis during the hatching phase. To a third subset of cores, we immediately initiated the hatching phase, without an experimental resting phase, to evaluate the effects induced during the resting phase. The most common zooplankton species that hatched was Eurytemora affinis (Copepoda), followed by Bosmina longispina maritima (Cladocera). In all cores that were subjected to a resting phase, the numbers of hatched E. affinis were log-linearly negatively related to density of M. affinis. An increase of M. affinis density from 1,000 to 5,000 individuals m(-2), normal field densities, reduced the hatching by 60-70%. The negative impact was mainly exerted during the hatching phase, suggesting predation on, burial of or physical injury of hatching nauplii or eggs in a late development stage as likely mechanisms. Also, the number of B. longispina maritima that hatched was reduced by M. affinis during the hatching phase, but no clear relation to density of M. affinis could be identified. The results show that M. affinis can reduce recruitment to zooplankton from benthic resting eggs. Such impact by the benthos on resting stages of zooplankton is therefore a potentially significant link between the benthic and pelagic systems.

  • 163.
    Albertsson, Jan
    et al.
    Umeå University, Faculty of Science and Technology, Umeå Marine Sciences Centre (UMF).
    Leonardsson, K
    Impact of a borrowing deposit-feeder, Monoporeia affinis, on viable zooplankton resting eggs in the northern Baltic Sea2000In: Marine Biology, ISSN 0025-3162, E-ISSN 1432-1793, Vol. 136, no 4, p. 611-619Article in journal (Refereed)
    Abstract [en]

    We investigated the effect of different densities of the burrowing deposit-feeding amphipod Monoporeia affinis on the potential for recruitment of zooplankton from benthic resting eggs. Hatching of resting eggs was induced in the laboratory on sliced and resuspended 1-cm depth-sections of sediment cores, collected at six stations ill an archipelago area of the Gulf of Bothnia, Baltic Sea. The uppermost 5 cm of the sediment was studied. The most common species that hatched was Eurytemor affinis (Copepoda). Individuals from another copepod genus, Acartia, hatched in significant numbers only in the cores from two stations with low amphipod abundance. Cores from stations with high amphipod densities showed a deeper distribution of emerging E. affinis nauplii compared with stations with few amphipods: the oxidised sediment layer was also deeper at high M. affinis densities than at low. Total (0 to 5 cm strata pooled) number of hatched E. affinis nauplii was independent of amphipod density. This indicates that the effect of M. affinis on E. affinis eggs involves deeper burial due to bioturbation, rather than predation. Decreased benthic recruitment of zooplankton at localities with high M. affinis density is suggested, since more deeply positioned eggs are less likely to hatch. When hatching was induced in intact, non-sliced cores from one station, the number of E. affinis nauplii that hatched was on average 43% of the number that hatched in the upper centimetre of the sliced cores from the same station. This fraction (43%), if applied to the other stations, implied a potential for benthic recruitment of up to 80000 ind m(-2) for E. affinis. Due to its high abundance, M. affinis is likely to greatly reduce benthic recruitment of zooplankton in this system.

  • 164.
    Albing, Malin
    et al.
    Department of Mathematics, Luleå University of Technology.
    Vännman, Kerstin
    Department of Mathematics, Luleå University of Technology.
    Elliptical safety region plots for Cpk2011In: Journal of Applied Statistics, ISSN 0266-4763, E-ISSN 1360-0532, Vol. 38, no 6, p. 1169-1187Article in journal (Refereed)
    Abstract [en]

    The process capability index C pk is widely used when measuring the capability of a manufacturing process. A process is defined to be capable if the capability index exceeds a stated threshold value, e.g. C pk >4/3. This inequality can be expressed graphically using a process capability plot, which is a plot in the plane defined by the process mean and the process standard deviation, showing the region for a capable process. In the process capability plot, a safety region can be plotted to obtain a simple graphical decision rule to assess process capability at a given significance level. We consider safety regions to be used for the index C pk . Under the assumption of normality, we derive elliptical safety regions so that, using a random sample, conclusions about the process capability can be drawn at a given significance level. This simple graphical tool is helpful when trying to understand whether it is the variability, the deviation from target, or both that need to be reduced to improve the capability. Furthermore, using safety regions, several characteristics with different specification limits and different sample sizes can be monitored in the same plot. The proposed graphical decision rule is also investigated with respect to power.

  • 165.
    Albrectsen, Benedicte R.
    et al.
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    Ericson, Lars
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Lundberg, Per
    Nutrient addition extends flowering display, which gets tracked by seed predators, but not by their parasitoids2008In: Oikos, ISSN 0030-1299, E-ISSN 1600-0706, Vol. 117, p. 473-480Article in journal (Refereed)
    Abstract [en]

    Although phenological matching between two and three trophic interactions has received some attention, it has largely been disregarded in explaining the lack of strong cascade dynamics in terrestrial systems. We studied the response of the specialist seed predator, Paroxyna plantaginis (Tephritidae) and associated generalist parasitoids (Chalcidoidea) to controlled fertilisation of individuals of naturally growing Tripolium vulgare (Asteraceae) on four island populations (Skeppsvik Archipelago, Sweden). We consistently found evidence of nutrient limitation: fertilised plants increased their biomass, produced more capitula (the oviposition units for tephritid flies), were more at risk of attack by the tephritids, and puparia were heavier in fertilised plants. During some parts of the season tephritids became more heavily parasitized, supporting the presence of cascade dynamics, however net parasitism over season decreased in response to nutrient addition. We found no evidence that capitulum size complicated parasitoid access to the tephritids, however the extended bud production prolonged the flowering season. Thus, tephritids utilized the surplus production of capitula throughout the entire season, while parasitoids did not expand their oviposition time window accordingly. Implications for top down regulation and cascade dynamics in the system are discussed.

  • 166.
    Albrectsen, Benedicte R
    et al.
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    Witzell, Johanna
    Robinson, Kathryn M
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    Wulff, Sören
    Luquez, Virginia MC
    Ågren, Rickard
    Jansson, Stefan
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    Large scale geographic clines of parasite damage to Populus tremula L2010In: Ecography, ISSN 0906-7590, E-ISSN 1600-0587, Vol. 33, no 3, p. 483-493Article in journal (Refereed)
    Abstract [en]

    In conclusion, clines of Phyllocnistis were stronger and more persistent compared to Melampsora, which showed contrasting clines of varying strength. Our data thus support the assumption of the GMTC model that clines exist in the border between hot and cold spots and that they may be less persistent for parasites with an elevated gene flow, and/or for parasites which cover relatively larger hot spots surrounded by fewer cold spots.

  • 167.
    Albrectsen, Benedicte Riber
    et al.
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    Siddique, Abu Bakar
    Decker, Vicki Huizu Guo
    Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC). Umeå University, Faculty of Science and Technology, Department of Plant Physiology.
    Unterseher, Martin
    Robinson, Kathryn M
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    Both plant genotype and herbivory shape aspen endophyte communities2018In: Oecologia, ISSN 0029-8549, E-ISSN 1432-1939, Vol. 187, no 2, p. 535-545Article in journal (Refereed)
    Abstract [en]

    Salicinoid phenolic glycosides are common defence substances in salicaceous trees and specialist leaf beetles use these compounds for their own defence against predators. Salicinoids vary qualitatively and qualitatively in aspen (Populus tremula) and this variation has a genetic basis. The foliar endophyte mycobiome is plentiful and we hypothesised that it is related to plant genotype, potentially mediated by salicinoid composition, and that interactions with the leaf beetle Chrysomela tremula may alter this relationship. We studied these three-way interactions in controlled greenhouse experiments. Endophytic fungi were isolated from sterilised leaf tissues with and without beetle damage, and from beetles. We confirmed that endophyte composition was influenced by host genotype. Beetle activity added generalist morphs to the mycobiome that overrode the initial host association. Yeast-like genera (Cryptococcus and Rhodotorula) were isolated only from beetle-damaged tissues and from beetles, whereas fast-growing filamentous fungi dominated beetle-free control plants. Competition experiments between filamentous fungi of plant origin and beetle-related yeasts suggested interaction of both stimulating and inhibiting modes of action amongst the fungi. As a result, we detected examples of amensalism, commensalism, parasitism and competition between the morphs tested, but we found no evidence of mutualism, and consequently no co-evolutionary relationship could be demonstrated, between yeasts carried by beetles, host genotype and associated filamentous morphs. Endophyte studies are method-dependent and high-throughput sequencing technology best define the fungal mycobiome, culturing however continues to be a cheap way to provide fundamental ecological insights and it is also required for experimental studies.

  • 168.
    Albán Reyes, Diana Carolina
    et al.
    Umeå University, Faculty of Science and Technology, Department of Chemistry. Umeå University.
    de Wit, Paul P.
    AkzoNobel Specialty Chemicals.
    Sundman, Ola
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Variation of the alkalisation conditions during the synthesis of a cellulose etherManuscript (preprint) (Other academic)
    Abstract [en]

    We show the effect of simultaneous variation of i) the NaOH/AGU (anhydroglucose unit) stoichiometric ratio (r), ii) added [NaOH], and iii) mercerization time, on the degree of cellulose substitution (DS), and by-product formation including proportions of insoluble particles and unreacted chemicals, in the synthesis of carboxymethylcellulose (CMC), under conditions resembling those often used for production of non-ionic cellulose ethers and without the use of alcohols. The DS was found to increase when (r) was increased (range 1.0-1.3) and added [NaOH] was decreased (range 50-30%). However, such changes also favoured the formation of unwanted by-products. Decreased (r) and increased [NaOH] resulted in increased the quantities of insoluble particles and unreacted chemicals. In the CMC samples, DS of 0.18-0.7 was obtained. The measured solubility (46%-86%) was lower than expected for a given DS. This, along with a deviation of the substituent distribution from the statistical calculations, indicated a high heterogeneity in the samples. The substitution at hydroxyl positions within the AGU shows the order of < ≈ , and that substitution increases with (r). The relative importance of substitution at increases with an increased [NaOH].

  • 169.
    Albán Reyes, Diana Carolina
    et al.
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Eliasson, Bertil
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Karlsson, Leif
    AkzoNobel.
    de Wit, Paul
    AkzoNobel.
    Svedberg, Anna
    MoRe Research.
    Sundman, Ola
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Activation of dissolving celluloses pulp for viscose and cellulose ether production2016In: The 7th workshop on cellulose, regenerated cellulose and cellulose derivatives / [ed] Ola Sundman, Umeå ; Karlstad: Umeå university ; Karlstad university , 2016, p. 29-30Conference paper (Other academic)
    Abstract [en]

    Mercerisation of cellulose by alkali treatment is the most common procedure used to activate natural cellulose fibres into many commercial cellulosic materials. During mercerisation, the NaOH solution enters the cellulose fibres, transforming them into a swollen and a highly reactive material called alkali cellulose (Na-Cell). In case NaOH is completely washed out of the cellulose structure, Na-Cell turns into Cellulose II upon drying.

    Traditionally the cellulose is mercerised by suspending it in a 15-20 % NaOH solution. The result is a high (15-25 mol/mol) NaOH: Anhydroglucose  molar ratio (r) and mercerisation in these conditions have been extensively studied. However, in modern production of cellulose ethers, the mercerisation conditions are often very different. The main reason is that any excess of water and OH--ions used during the mercerisation can later react with different chemicals in the process, thus forming unwanted by-products e.g. methanol. One way to avoid this kind of side reaction is by using low-water-content mercerisation conditions, i.e. low (r) = 0.8-1.8 mol/mol and high NaOH concentration (45-55% w/w). The traditional mercerisation is a suspension process while the cellulose during the latter process, i.e low-water-content mercerisation conditions, remains quite “dry”. Thus, although the chemical reaction principles of activation of cellulose for both viscose and cellulose ethers processes are the same, the activation conditions used are often very different. Therefore, the different dependencies of process parameters as well as any similarities between the processes are interesting.

    The presentation summarises the findings presented in two papers which described the influence of the different parameters on the mercerisation/activation of softwood Sulphite dissolving pulp in viscose production conditions (Albán Reyes et al. 2016) and cellulose derivatives production conditions (Albán Reyes et al.) respectively. In the individual studies this has been done by analysing the degree of transformation (DoT) of dissolving pulp to Na-cellulose (or more correctly cellulose II after washing and upon drying) as a function of simultaneous variation of [NaOH], temperature, and reaction time varied using design of experiment. Also the (r) was varied for samples mercerised at dry conditions. A combination of Raman imaging and multivariate data analysis have been used to study the DoT to Cellulose II.

    It was found that the mercerisation under the different conditions was dependent on different parameters. For traditional mercerisation, on the one hand, the temperature was shown to be important for the DoT and showed negative correlation with the data, while [NaOH] showed a positive correlation. On the other hand, at low-water-content mercerisation conditions the (r) was overall most important while the temperature showed no statistical importance in a Partial least squares analysis. Traditional mercerisation gave much higher DoT than the low-water-content mercerisation. Thus,  the data for low-water-content mercerisation was further examined at the different (r). The same chemistry is always expected and the different influences of the parameters seen is understood and discussed in terms of the different physical reaction mechanisms.  

  • 170.
    Albán Reyes, Diana Carolina
    et al.
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Skoglund, Nils
    Umeå University, Faculty of Science and Technology, Department of Chemistry. Department of Engineering Sciences and Mathematics, Luleå University of Technology, Luleå, Sweden .
    Svedberg, Anna
    Eliasson, Bertil
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Sundman, Ola
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    The influence of different parameters on the mercerisation of cellulose for viscose production2016In: Cellulose (London), ISSN 0969-0239, E-ISSN 1572-882X, Vol. 23, no 2, p. 1061-1072Article in journal (Refereed)
    Abstract [en]

    A quantitative analysis of degree of transformation from a softwood sulphite dissolving pulp to alkalised material and the yield of this transformation as a function of the simultaneous variation of the NaOH concentration, denoted [NaOH], reaction time and temperature was performed. Samples were analysed with Raman spectroscopy in combination with multivariate data analysis and these results were confirmed by X-ray diffraction. Gravimetry was used to measure the yield. The resulting data were related to the processing conditions in a Partial Least Square regression model, which made it possible to explore the relevance of the three studied variables on the responses. The detailed predictions for the interactive effects of the measured parameters made it possible to determine optimal conditions for both yield and degree of transformation in viscose manufacturing. The yield was positively correlated to the temperature from room temperature up to 45 A degrees C, after which the relation was negative. Temperature was found to be important for the degree of transformation and yield. The time to reach a certain degree of transformation (i.e. mercerisation) depended on both temperature and [NaOH]. At low temperatures and high [NaOH], mercerisation was instantaneous. It was concluded that the size of fibre particles (mesh range 0.25-1 mm) had no influence on degree of transformation in viscose processing conditions, apparently due to the quick reaction with the excess of NaOH.

  • 171.
    Albán Reyes, Diana Carolina
    et al.
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Stridh, Kjell
    AkzoNobel, Stenungsund, Sverige.
    de Wit, Paul P.
    AkzoNobel, Arnhem, The Netherlands.
    Sundman, Ola
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Is there a diffusion of alkali in the activation of dissolving cellulose pulp at low NAOH stoichiometric excess?2019In: Cellulose (London), ISSN 0969-0239, E-ISSN 1572-882X, Vol. 26, no 2, p. 1297-1308Article in journal (Refereed)
    Abstract [en]

    We conducted a quantitative study, following the degree of activation (i.e. the transformation to alkali cellulose, denoted as DoA) over time for dissolving cellulose pulp treated with different [NaOH] at low NaOH/anhydroglucose unit stoichiometric ratio (denoted as (r) ≤ 2.6). Our quantitative approach was based on Raman spectroscopy data, evaluated by partial least squares regression modelling. The results show strong influence of the (r) on DoA (increasing from DoA= 45% at (r) = 0.8, to DoA = 85% at (r) = 2.6), and its complex dependence on [NaOH]. At (r) = 0.8 the highest DoA (DoA ≳ 60%) was found at 30% [NaOH], while at (r) =1.3 it was found at 20% [NaOH] (DoA ≳ 80%). Although activation of cellulose happens in minutes at the studied temperature (30 °C), it was found that the reaction may be slow when a low (r) is used. A gradual increase of the DoA from ≈ 30% to ≈ 70% in time was seen when samples were activated with 30% [NaOH] at (r) = 0.8. At the same (r), a similar increase of DoA from ≈ 30 % to ≈ 60 % was also observed when 40% [NaOH] was used. Slow diffusion of NaOH through poorly swollen cellulose fibres is proposed as an explanation for this phenomenon. Lastly, solid-state CP/MAS NMR measurements suggest that at a fixed temperature, the Na-Cell allomorph mostly depends on [NaOH]. However, in the transition area between Na-Cell I and Na-Cell II, its influence might be affected by (r). 

  • 172.
    Albán Reyes, Diana Carolina
    et al.
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Sundman, Ola
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Schröder, Ulf
    AkzoNobel.
    Karlsson, Leif
    AkzoNobel.
    de Wit, Paul
    AkzoNobel.
    Eliasson, Bertil
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Activation of dissolving cellulose pulp at low water content2015In: 4th EPNOE International Polysaccharide Conference: Polysaccharides and polysaccharide-based advance materials: from science to industry, 2015Conference paper (Other academic)
    Abstract [en]

    Mercerisation of cellulose by alkali treatment is the first step in modifying natural cellulose fibres into many commercial cellulosic materials. During treatment, the fiber transforms into a reactive and highly swollen material called alkali cellulose (Na-Cell). In case NaOH is washed out of the cellulose structure, Na-Cell turn into Cellulose II upon drying (Langan et al. 2001).

     

    The aim of the present study was to gain a better understanding of the mercerisation of dissolving cellulose pulp at low water content. This has been done by spraying NaOH onto milled cellulose in a kneader, then washing the cellulose to neutrality to stop the reaction. After drying the transformation degree to cellulose II was analysed. The experiments include variation of temperature (30-60°C), reaction time (5 and 25 min), [NaOH] (45-55%), and NaOH:Cellulose molar ratio (0.8- 1.8). A combination of NIR Raman imaging and multivariate data analysis have been used to study the transformation degree.

     

    To the authors’ knowledge, this is the first time the influence of NaOH: Cellulose molar ratio on the mercerisation process has been studied in a single model together with temperature, reaction time and [NaOH]. Our results indicate that increased NaOH: Cellulose molar ratio has a significant positive influence on transformation degree of dissolving cellulose pulp at low water content.

  • 173. Alcocer, M. J. C.
    et al.
    Murtagh, G. J.
    Mirotti, L.
    Brans, A.
    Harnett, W.
    Rundqvist, Louise
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Larsson, Göran
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    The allergenicity of 2S plant albumins2011In: Clinical and Experimental Allergy, ISSN 0954-7894, E-ISSN 1365-2222, Vol. 41, no 12, p. 1827-1827Article in journal (Refereed)
  • 174. Aldea, Steliana
    et al.
    Snåre, Mathias
    Eränen, Kari
    Grenman, Henrik
    Rautio, Anne-Riika
    Kordás, Krisztian
    Mikkola, Jyri-Pekka
    Umeå University, Faculty of Science and Technology, Department of Chemistry. Laboratory of Industrial Chemistry and Reaction Engineering, Johan Gadolin Process Chemistry Centre, Åbo Akademi University, Biskopsgatan 8, 20500 Åbo-Turku, Finland.
    Salmi, Tapio
    Murzin, Dmitry Y.
    Crystallization of Nano-Calcium Carbonate: The Influence of Process Parameters2016In: Chemie Ingenieur Technik, ISSN 0009-286X, E-ISSN 1522-2640, Vol. 88, no 11, p. 1609-1616Article in journal (Refereed)
    Abstract [en]

    Precipitated calcium carbonate was synthesized by carbonation of calcium hydroxide in the presence and absence of ultrasound (conventional stirring) at atmospheric as well as at elevated pressures and different initial concentrations of Ca(OH)2. Spherical morphology of the formed calcite was favored at high Ca(OH)2 concentrations and low CO2 pressures. The presence of ultrasound did not show any influence on the reaction rate in case of efficient mixing. A small increase of the reaction rate was observed at lower CO2 pressures. Elevated pressures in combination with ultrasound did not lead to notable changes of reaction rate or particle morphology.

  • 175. Alekeyenko, Artyom A.
    et al.
    Ho, Joshua W. K.
    Peng, Shouyong
    Gelbart, Marnie
    Tolstorukov, Michael Y.
    Plachetka, Annette
    Kharchenko, Peter V.
    Jung, Youngsook L.
    Gorchakov, Andrey A.
    Larschan, Erica
    Gu, Tingting
    Minoda, Aki
    Riddle, Nicole C.
    Schwartz, Yuri B.
    Umeå University, Faculty of Medicine, Department of Molecular Biology (Faculty of Medicine).
    Elgin, Sarah C. R.
    Karpen, Gary H.
    Pirrotta, Vincenzo
    Kuroda, Mitzi I.
    Park, Peter J.
    Sequence-Specific Targeting of Dosage Compensation in Drosophila Favors an Active Chromatin Context2012In: PLoS Genetics, ISSN 1553-7390, Vol. 8, no 4, p. e1002646-Article in journal (Refereed)
    Abstract [en]

    The Drosophila MSL complex mediates dosage compensation by increasing transcription of the single X chromosome in males approximately two-fold. This is accomplished through recognition of the X chromosome and subsequent acetylation of histone H4K16 on X-linked genes. Initial binding to the X is thought to occur at "entry sites" that contain a consensus sequence motif ("MSL recognition element" or MRE). However, this motif is only similar to 2 fold enriched on X, and only a fraction of the motifs on X are initially targeted. Here we ask whether chromatin context could distinguish between utilized and non-utilized copies of the motif, by comparing their relative enrichment for histone modifications and chromosomal proteins mapped in the modENCODE project. Through a comparative analysis of the chromatin features in male S2 cells (which contain MSL complex) and female Kc cells (which lack the complex), we find that the presence of active chromatin modifications, together with an elevated local GC content in the surrounding sequences, has strong predictive value for functional MSL entry sites, independent of MSL binding. We tested these sites for function in Kc cells by RNAi knockdown of Sxl, resulting in induction of MSL complex. We show that ectopic MSL expression in Kc cells leads to H4K16 acetylation around these sites and a relative increase in X chromosome transcription. Collectively, our results support a model in which a pre-existing active chromatin environment, coincident with H3K36me3, contributes to MSL entry site selection. The consequences of MSL targeting of the male X chromosome include increase in nucleosome lability, enrichment for H4K16 acetylation and JIL-1 kinase, and depletion of linker histone H1 on active X-linked genes. Our analysis can serve as a model for identifying chromatin and local sequence features that may contribute to selection of functional protein binding sites in the genome.

  • 176. Aleksandrovskii, A. N.
    et al.
    Dolbin, A.V.
    Esel'son, V.B.
    Gavrilko, V.G.
    Manzhelii, V.G.
    Udovidchenko, B.G.
    Bakai, A.S.
    Gadd, G.E.
    Moricca, S.
    Sundqvist, Bertil
    Umeå University, Faculty of Science and Technology, Department of Physics.
    Low-temperature thermal expansion of pure and inert gas-doped fullerite C602003In: Fizika Nizkikh Temperatur (Kharkov), ISSN 0132-6414 (Print) 1816-0328 (On-line), Vol. 29, no 4, p. 432-442Article in journal (Refereed)
    Abstract [en]

    The low temperature (2–24 K) thermal expansion of pure (single-crystal and polycrystalline) C60 and polycrystalline C60 intercalated with He, Ne, Ar, and Kr has been investigated using the high-resolution capacitance dilatometer. The investigation of the time dependence of the sample length variations deltaL(t) on heating by deltaT shows that the thermal expansion is determined by the sum of positive and negative contributions, which have different relaxation times. The negative thermal expansion usually prevails at helium temperatures. The positive expansion is connected with the phonon thermalization of the system. The negative expansion is caused by reorientation of the C60 molecules. It is assumed that the reorientation is of a quantum character. The inert gas impurities affect the reorientation of the C60 molecules very strongly, especially at liquid helium temperatures. A temperature hysteresis of the thermal expansion coefficient of Kr– and He–C60 solutions has been revealed. The hysteresis is attributed to orientational polyamorphous transformation in these systems.

  • 177. Aleksandrovskii, A. N.
    et al.
    Esel'son, V.B.
    Manzhelii, Vadim Grigorovich
    Udovidchenko, B.G.
    Soldatov, Alexander
    Umeå University, Faculty of Science and Technology, Department of Physics.
    Sundqvist, Bertil
    Umeå University, Faculty of Science and Technology, Department of Physics.
    Negative thermal expansion of fullerite C60 at helium temperatures1997In: Low temperature physics (Woodbury, N.Y., Print), ISSN 1063-777X, E-ISSN 1090-6517, Vol. 23, no 11, p. 943-946Article in journal (Refereed)
    Abstract [en]

    The thermal expansion of fullerite C60 has been measured in the temperature range 2–9 K. A compacted fullerite sample with a diameter of about 6 mm and height of 2.4 mm was used. It was found that at temperatures below ~ 3.4 K the linear thermal expansion coefficient becomes negative. At temperatures above 5 K our results are in good agreement with the available literature data. A qualitative explanation of the results is proposed

  • 178. Aleksandrovskii, A. N.
    et al.
    Esel'son, V.B.
    Manzhelii, V.G.
    Udovidchenko, B.G.
    Soldatov, Alexander
    Umeå University, Faculty of Science and Technology, Department of Physics.
    Sundqvist, Bertil
    Umeå University, Faculty of Science and Technology, Department of Physics.
    Thermal expansion of single-crystal fullerite C60 at helium temperatures2000In: Low temperature physics (Woodbury, N.Y., Print), ISSN 1063-777X, E-ISSN 1090-6517, Vol. 26, no 1, p. 75-80Article in journal (Refereed)
    Abstract [en]

    The thermal expansion of single-crystal fullerite C60 has been studied in the range of liquid-helium temperatures (2–10 K). At temperatures below ~4.5 K the thermal expansion of fullerite C60 becomes negative, in agreement with the previous results on polycrystalline materials. A qualitative explanation of the results is proposed.

  • 179. Aleksandrovskii, A. N.
    et al.
    Gavrilko, V.G.
    Esel'son, V.B.
    Manzhelii, V. G.
    Udovidchenko, B.G.
    Maletskiy, V.P.
    Sundqvist, Bertil
    Umeå University, Faculty of Science and Technology, Department of Physics.
    Effect of argon on the thermal expansion of fullerite C60 at helium temperatures2001In: Low temperature physics (Woodbury, N.Y., Print), ISSN 1063-777X, E-ISSN 1090-6517, Vol. 27, no 3, p. 245-246Article in journal (Refereed)
    Abstract [en]

    The linear thermal expansion of compacted Ar-doped fullerite C60(ArxC60) is investigated at 2–12 K using a dilatometric method. The thermal expansion of ArxC60 is also studied after partial desaturation of argon from fullerite. It is revealed that argon doping resulted in a considerable change of the temperature dependence of the thermal expansion of fullerite. An explanation of the observed effects is proposed.

  • 180. Aleksandrovskii, A.N.
    et al.
    Bakai, A.S.
    Cassidy, D.
    Dolbin, A.V.
    Esel'son, V.B.
    Gadd, G.E.
    Gavrilko, V.G.
    Manzhelii, V.G.
    Moricca, S.
    Sundqvist, Bertil
    Umeå University, Faculty of Science and Technology, Physics.
    On the polyamorphism of fullerite-based orientational glasses.2005In: Low Temperature Physics, ISSN 1063-777X, Vol. 31, no 5, p. 429-444Article in journal (Refereed)
    Abstract [en]

    The dilatometric investigation in the temperature range of 2–28 K shows that a first-order

    polyamorphous transition occurs in the orientational glasses based on C60 doped with H2, D2 and

    Xe. A polyamorphous transition was also detected in C60 doped with Kr and He. It is observed that

    the hysteresis of thermal expansion caused by the polyamorphous transition (and, hence, the transition

    temperature) is essentially dependent on the type of doping gas. Both positive and negative

    contributions to the thermal expansion were observed in the low-temperature phase of the glasses.

    The relaxation time of the negative contribution occurs to be much longer than that of the positive

    contribution. The positive contribution is found to be due to phonon and libron modes, whilst the

    negative contribution is attributed to tunneling states of the C60 molecules. The characteristic

    time of the phase transformation from the low-T phase to the high-T phase has been found for the

    C60–H2 system at 12 K. A theoretical model is proposed to interpret these observed phenomena.

    The theoretical model proposed, includes a consideration of the nature of polyamorphism in

    glasses, as well as the thermodynamics and kinetics of the transition. A model of noninteracting

    tunneling states is used to explain the negative contribution to the thermal expansion. The experimental

    data obtained is considered within the framework of the theoretical model. From the theoretical

    model the order of magnitude of the polyamorphous transition temperature has been estimated.

    It is found that the late stage of the polyamorphous transformation is described well by the

    Kolmogorov law with an exponent of n = 1. At this stage of the transformation, the two-dimensional

    phase boundary moves along the normal, and the nucleation is not important.

  • 181. Aleksandrovskii, A.N.
    et al.
    Gavrilko, V.G.
    Esel'son, V.B.
    Manzhelii, V. G.
    Udovidchenko, B.G.
    Maletskiy, V.P.
    Sundqvist, Bertil
    Umeå University, Faculty of Science and Technology, Department of Physics.
    Thermal expansion of fullerite C60 alloyed with argon and neon2001In: Low temperature physics (Woodbury, N.Y., Print), ISSN 1063-777X, E-ISSN 1090-6517, Vol. 27, no 12, p. 1033-1036Article in journal (Refereed)
    Abstract [en]

    The linear thermal expansion of compacted fullerite C60 alloyed with argon (ArxC60) and neon (NexC60) are investigated by a dilatometric method. The experimental temperature is 2–12 K. In the same temperature interval the thermal expansion of ArxC60 and NexC60 are examined after partial desaturation of the gases from fullerite. It is found that Ar and Ne alloying affects the temperature dependence of the thermal expansion coefficient of C60 quite appreciably. The libration and translation contributions to the thermal expansion of pure C60 are separated. The experimental results on the thermal expansion are used to obtain the Debye temperature of pure C60. The effects observed are tentatively interpreted.

  • 182.
    Alekzandra, Granath
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Filmskapande för nybörjare - steg för steg2017Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This report is about film making, wich parts that are included in film making and things that is good to think of when doing film for the first time. A short movie has been created and from this, this study has been done to figure out if the theory is like the reality. Also the report is based om the book ”How to get started in film making” by Tom Holden and interviews with people working with film.

  • 183.
    Alenius, Mattias
    et al.
    Umeå University, Faculty of Medicine, Department of Molecular Biology (Faculty of Medicine). Umeå University.
    Bohm, Staffan
    Umeå University, Faculty of Medicine, Department of Molecular Biology (Faculty of Medicine). Umeå University, Faculty of Science and Technology, Department of Molecular Biology (Faculty of Science and Technology).
    Identification of a novel neural cell adhesion molecule-related gene with a potential role in selective axonal projection1997In: Journal of Biological Chemistry, ISSN 0021-9258, E-ISSN 1083-351X, Vol. 272, no 42, p. 26083-26086Article in journal (Refereed)
    Abstract [en]

    We describe here the cloning of mouse complementary DNAs encoding a novel protein, Rb-8 neural cell adhesion molecule (RNCAM), with a predicted extracellular region of five immunoglobulin Ca-type domains followed by two fibronectin type III domains, Alternative splicing is likely to generate two RNCAM isoforms, which are differently attached to the cell membrane, These structural features and overall sequence identity identify this protein as a novel member of a cell adhesion molecule subgroup together with vertebrate neural cell adhesion molecule, Aplysia cell adhesion molecule, and Drosophila fasciclin II, In insects, fasciclin II is present on a restricted subset of embryonic central nervous system axons where it controls selective axon fasciculation. Intriguingly, RNCAM likewise is expressed in subsets of olfactory and vomeronasal neurons with topographically defined axonal projections, The spatial expression RNCAM corresponds precisely to that of certain odorant receptor expression zones of the olfactory epithelium. These expression patterns thus render RNCAM the first described cell adhesion molecule with a potential regulatory role in formation of selective axonal projections important for olfactory sensory information coding.

  • 184.
    Aler Tubella, Andrea
    et al.
    Umeå University, Faculty of Science and Technology, Department of Computing Science.
    Dignum, Virginia
    Umeå University, Faculty of Science and Technology, Department of Computing Science.
    The Glass Box Approach: Verifying Contextual Adherence to Values2019Conference paper (Refereed)
    Abstract [en]

    Artificial Intelligence (AI) applications are beingused to predict and assess behaviour in multiple domains, such as criminal justice and consumer finance, which directly affect human well-being. However, if AI is to be deployed safely, then people need to understand how the system is interpreting and whether it is adhering to the relevant moral values. Even though transparency is often seen as the requirement in this case, realistically it might notalways be possible or desirable, whereas the needto ensure that the system operates within set moral bounds remains.

    In this paper, we present an approach to evaluate the moral bounds of an AI system based on the monitoring of its inputs and outputs. We place a ‘Glass Box’ around the system by mapping moral values into contextual verifiable norms that constrain inputs and outputs, in such a way that if these remain within the box we can guarantee that the system adheres to the value(s) in a specific context. The focus on inputs and outputs allows for the verification and comparison of vastly different intelligent systems–from deep neural networks to agent-based systems–whereas by making the context explicit we exposethe different perspectives and frameworks that are taken into account when subsuming moral values into specific norms and functionalities. We present a modal logic formalisation of the Glass Box approach which is domain-agnostic, implementable, and expandable.

  • 185.
    Aler Tubella, Andrea
    et al.
    Umeå University.
    Theodorou, Andreas
    Umeå University.
    Dignum, Frank
    Umeå University.
    Dignum, Virginia
    Umeå University.
    Governance by Glass-Box: Implementing Transparent Moral Bounds for AI Behaviour2019In: Proceedings of the 28th International Joint Conference on Artificial Intelligence, 2019Conference paper (Other academic)
    Abstract [en]

    Artificial Intelligence (AI) applications are being used to predict and assess behaviour in multiple domains which directly affect human well-being. However, if AI is to improve people’s lives, then people must be able to trust it, by being able to understand what the system is doing and why. Although transparency is often seen as the requirementin this case, realistically it might not always be possible, whereas the need to ensure that the system operates within set moral bounds remains.

    In this paper, we present an approach to evaluate the moral bounds of an AI system based on the monitoring of its inputs and outputs. We place a ‘Glass-Box’ around the system by mapping moral values into explicit verifiable norms that constrain inputs and outputs, in such a way that if these remain within the box we can guarantee that the system adheres to the value. The focus on inputs and outputs allows for the verification and comparison of vastly different intelligent systems; from deep neural networks to agent-based systems.

    The explicit transformation of abstract moral values into concrete norms brings great benefits interms of explainability; stakeholders know exactly how the system is interpreting and employing relevant abstract moral human values and calibrate their trust accordingly. Moreover, by operating at a higher level we can check the compliance of the system with different interpretations of the same value.

  • 186. Alessi, Daniel S.
    et al.
    Lezama-Pacheco, Juan S.
    Stubbs, Joanne E.
    Janousch, Markus
    Bargar, John R.
    Persson, Per
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Bernier-Latmani, Rizlan
    The product of microbial uranium reduction includes multiple species with U(IV)-phosphate coordination2014In: Geochimica et Cosmochimica Acta, ISSN 0016-7037, E-ISSN 1872-9533, Vol. 131, p. 115-127Article in journal (Refereed)
    Abstract [en]

    Until recently, the reduction of U(VI) to U(IV) during bioremediation was assumed to produce solely the sparingly soluble mineral uraninite, UO2(s). However, results from several laboratories reveal other species of U(IV) characterized by the absence of an EXAFS U-U pair correlation (referred to here as noncrystalline U(IV)). Because it lacks the crystalline structure of uraninite, this species is likely to be more labile and susceptible to reoxidation. In the case of single species cultures, analyses of U extended X-ray fine structure (EXAFS) spectra have previously suggested U(IV) coordination to carboxyl, phosphoryl or carbonate groups. In spite of this evidence, little is understood about the species that make up noncrystalline U(IV), their structural chemistry and the nature of the U(IV)-ligand interactions. Here, we use infrared spectroscopy (IR), uranium L-III-edge X-ray absorption spectroscopy (XAS), and phosphorus K-edge XAS analyses to constrain the binding environments of phosphate and uranium associated with Shewanella oneidensis MR-1 bacterial cells. Systems tested as a function of pH included: cells under metal-reducing conditions without uranium, cells under reducing conditions that produced primarily uraninite, and cells under reducing conditions that produced primarily biomass-associated noncrystalline U(IV). P X-ray absorption near-edge structure (XANES) results provided clear and direct evidence of U(IV) coordination to phosphate. Infrared (IR) spectroscopy revealed a pronounced perturbation of phosphate functional groups in the presence of uranium. Analysis of these data provides evidence that U(IV) is coordinated to a range of phosphate species, including monomers and polymerized networks. U EXAFS analyses and a chemical extraction measurements support these conclusions. The results of this study provide new insights into the binding mechanisms of biomass-associated U(IV) species which in turn sheds light on the mechanisms of biological U(VI) reduction. (C) 2014 Elsevier Ltd. All rights reserved.

  • 187.
    Alewell, C
    et al.
    Institute of Environmental Geosciences, University of Basel, Switzerland.
    Giesler, Reiner
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Klaminder, Jonatan
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Leifeld, J
    Agroscope Reckenholz-Tanikon Research Station ART, Switzerland.
    Rollog, M
    Institute of Environmental Geosciences, University of Basel, Switzerland.
    Stable carbon isotopes as indicators for environmental change inpalsa peats2011In: Biogeosciences, ISSN 1726-4170, E-ISSN 1726-4189, Vol. 8, p. 1769-1778Article in journal (Refereed)
    Abstract [en]

    Palsa peats are unique northern ecosystems formed under an arctic climate and characterized by a high biodiversity and sensitive ecology. The stability of the palsas are seriously threatened by climate warming which will change the permafrost dynamic and induce a degradation of the mires.

    We used stable carbon isotope depth profiles in two palsa mires of Northern Sweden to track environmental change during the formation of the mires. Soils dominated by aerobic degradation can be expected to have a clear increase of carbon isotopes (δ13C) with depth, due to preferential release of 12C during aerobic mineralization. In soils with suppressed degradation due to anoxic conditions, stable carbon isotope depth profiles are either more or less uniform indicating no or very low degradation or depth profiles turn to lighter values due to an enrichment of recalcitrant organic substances during anaerobic mineralisation which are depleted in 13C.

    The isotope depth profile of the peat in the water saturated depressions (hollows) at the yet undisturbed mire Storflaket indicated very low to no degradation but increased rates of anaerobic degradation at the Stordalen site. The latter might be induced by degradation of the permafrost cores in the uplifted areas (hummocks) and subsequent breaking and submerging of the hummock peat into the hollows due to climate warming. Carbon isotope depth profiles of hummocks indicated a turn from aerobic mineralisation to anaerobic degradation at a peat depth between 4 and 25 cm. The age of these turning points was 14C dated between 150 and 670 yr and could thus not be caused by anthropogenically induced climate change. We found the uplifting of the hummocks due to permafrost heave the most likely explanation for our findings. We thus concluded that differences in carbon isotope profiles of the hollows might point to the disturbance of the mires due to climate warming or due to differences in hydrology. The characteristic profiles of the hummocks are indicators for micro-geomorphic change during permafrost up heaving.

  • 188.
    Alewell, C
    et al.
    Institute of Environmental Geosciences, University of Basel, Switzerland.
    Giesler, Reiner
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Klaminder, Jonatan
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Leifeld, J
    Agroscope Reckenholz-Tänikon Research Station ART, Switzerland.
    Rollog, M
    Institute of Environmental Geosciences, University of Basel, Switzerland.
    Stable carbon isotopes as indicators for micro-geomorphic changes in palsa peats2011In: Biogeoscience Discussions, ISSN 1810-6277, Vol. 8, no 1, p. 527-548Article in journal (Refereed)
    Abstract [en]

    Palsa peats are unique northern ecosystems formed under an arctic climate and characterizedby an unique biodiversity and ecology. The stability of the palsas are seriouslythreatened by climate warming which will change the permafrost dynamic and5 results in degradation of the mires. We used stable carbon isotope depth profiles intwo palsa mires of Northern Sweden to track environmental change during the formationof the mires. Carbon isotope (13C) depth profile of the yet undisturbed mireStorflaket indicated very low to no degradation of the peat in the water saturated depressions(hollows) but increased rates of anaerobic degradation at the Stordalen site.10 The latter might be induced by degradation of the permafrost cores in the uplifted areas(hummocks) and subsequent braking and submerging of the hummock peat intothe hollows due to climate warming. Carbon isotope depth profiles of hummocks indicateda turn from aerobic mineralisation to anaerobic degradation at a peat depthbetween 4 to 25 cm. The age of these turning point was 14C dated between 150 and15 670 years and could thus not be caused by anthropogenically induced climate change.We found the uplifting of the hummocks due to permafrost heave the most likely explanationfor our findings. We thus concluded that differences in carbon isotope profiles ofthe hollows might point to the disturbance of the mires due to climate warming or dueto differences in hydrology. The characteristic profiles of the hummocks are indicators20 for micro-geomorphic change during permafrost up heaving.

  • 189.
    Alexander, Bodén
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Kommunikation och marknadsföring inom Sociala medier – Novamedia Svenska PostkodLotteriet AB2015Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    When I worked with the daily communication with the lottery’s customers on social media the Communications Department at Nova Media Swedish Postcode Lottery contacted me to write a document, plan and present an advertising campaign in their social media channels to Christmas 2014. The company had ideas on a campaign that they wanted develop where my job was to develop and present a plan for how to implement the campaign. The purpose is to explain what PostkodTomten is and to highlight its commercial advantages for marketing purposes. To have succeeded with this work, I needed a clear methodology and plan. I deepened my knowledge in marketing with a clear focus on social media, literary studies has been key and theoretical studies have been a good basis to implement my work practically. The conclusion I take with me in the future, the importance of how to dispose of your work, meetings booked weekly and milestones were set up giving the project good order and structure. This report will first and foremost focus and process these documents but also contains a theoretical part of marketing and communications in social media in general. The document and the report were presented to the company as an appendix. The theoretical parts of the report focuses on the marketing and communications in social media, how it is going to and how to do it appropriately. It is also up to what a company can do to strategically "stick out" and promote themselves on social media and its various channels. The terms "Buzz marketing" and "viral marketing" will also be explained.

  • 190.
    Alexeyev, O. A.
    et al.
    Umeå University, Faculty of Medicine, Department of Medical Biosciences, Pathology.
    Jahns, A. C.
    Umeå University, Faculty of Medicine, Department of Medical Biosciences, Pathology.
    Sampling and detection of skin Propionibacterium acnes: Current status2012In: Anaerobe, ISSN 1075-9964, E-ISSN 1095-8274, Vol. 18, no 5, p. 479-483Article, review/survey (Refereed)
    Abstract [en]

    A connection between acne vulgaris and Propionibacterium acnes has long been suggested. Over the years, several human skin microbiota sampling methods have been evolved and applied, e.g. swab, scrape, extraction techniques including cyanoacrylate gel sampling as well as punch biopsy. Collected samples have been processed following various methodologies ranging from culture studies to probe labelling and molecular analysis. Direct visualization techniques have recently shown the existence of anatomically distinct skin P acnes populations: epidermal and follicular. P. acnes biofilms appear to be a common phenomenon. Current sampling approaches target different skin populations of P. acnes and the presence of microbial biofilms can influence the retrieval of P. acnes. The anatomical considerations must be taken into account while interpreting microbiological data. (C) 2012 Elsevier Ltd. All rights reserved.

  • 191.
    Alfredsson, Jessica
    Umeå University, Faculty of Social Sciences, Department of Psychology.
    INNOVATIVE TOOL-MODIFICATIONS AND TOOL SELECTIVITY IN NEW CALEDONIAN CROWS (CORVUS MONEDULOIDES)2012Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Tool-use and tool-manufacture are thought to require high cognitive skills and have been considered as an exclusive attribute to primates. Recent observations of New Caledonian crows (NCCs) challenge this assumption. In this study 13 NCCs were tested with two different tool production tasks. The NCC either had to straighten a hook or bend a stick to retrieve food from two different kinds of tree trunks. The result showed that 3/5 birds bent sticks and used them to retrieve food and 1/5 birds straightened hooks to retrieve food. The birds managed to solve both tasks but not the birds in the control group. This indicates that NCC's tool making is a flexible innovative act and not just an innate predisposition to bend flexible material. This finding is interesting given that recent studies on human children show that below 8 years of age children fail in similar innovative tool making tasks.

  • 192.
    Alftberg Melin, Mattias
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Change in growth and overall condition in populations of anadromous burbot (Lota lota) in the Gulf of Bothnia2019Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Many populations of burbot (Lota lota)around the world have been extirpated, are endangered or are in serious decline both regarding numbers but also in size. The aim of this study was to investigate if growth and overall condition in populations of anadromous burbot in the Gulf of Bothnia has changed over time and if so, discuss potential causes behind. This was done by comparing size at age and individual level condition indices of the two populations of anadromous burbot in Sävarån and Rickleån to previous studies from the same rivers. The results showed thatgrowth of young burbot has increased between the time period 2001-2014 to 2019in Sävarånand also a change towards a higher frequency of young individuals and a lack of older ones. Furthermore, an increase over time in condition was observed in Sävarån. In Rickleån the growth at the age of 3 had increased from both 1969-1971 and 2001-2014 to 2019. At the age of 4 to 9 a decrease in growth was shown from the time period 1969-1971 to 2001-2014 in Rickleån. A shift towards warmer water temperatures due to climate change might be an explanation in the observed change in both growth and condition in the population of burbots in Sävarån and Rickleån. Furthermore, the observed change in age frequency in Sävarån could also be a result of an increase in water temperature but could also be an effect of restoration and the control of pH in Sävarån.

  • 193.
    Al-Furoukh, Natalie
    et al.
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Ianni, Alessandro
    Nolte, Hendrik
    Hölper, Soraya
    Krüger, Marcus
    Wanrooij, Sjoerd
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Braun, Thomas
    ClpX stimulates the mitochondrial unfolded protein response (UPRmt) in mammalian cells2015In: Biochimica et Biophysica Acta. Molecular Cell Research, ISSN 0167-4889, E-ISSN 1879-2596, Vol. 1853, no 10, p. 2580-2591Article in journal (Refereed)
    Abstract [en]

    Proteostasis is crucial for life and maintained by cellular chaperones and proteases. One major mitochondrial protease is the ClpXP complex, which is comprised of a catalytic ClpX subunit and a proteolytic ClpP subunit. Based on two separate observations, we hypothesized that ClpX may play a leading role in the cellular function of ClpXP. Therefore, we analyzed the effect of ClpX overexpression on a myoblast proteome by quantitative proteomics. ClpX overexpression results in the upregulation of markers of the mitochondria( proteostasis pathway, known as the "mitochondrial unfolded protein response" (UPRmt). Although this pathway is described in detail in Caenorhabditis elegans, it is not clear whether it is conserved in mammals. Therefore, we compared features of the classical nematode UPRmt with our mammalian ClpX-triggered UPRmt dataset. We show that they share the same retrograde mitochondria-to-nucleus signaling pathway that involves the key UPRmt transcription factor CHOP (also known as Ddit3, CEBPZ or GADD153). In conclusion, our data confirm the existence of a mammalian UPRmt that has great similarity to the C elegans pathway. Furthermore, our results illustrate that ClpX overexpression is a good and simple model to study the underlying mechanisms of the UPRmt in mammalian cells.

  • 194.
    Alger, Susanne
    Umeå University, Faculty of Social Sciences, Department of applied educational science.
    Is This Reliable Enough?: Examining Classification Consistency and Accuracy in a Criterion-Referenced Test2016In: International journal of assessment tools in education, ISSN 2148-7456, Vol. 3, no 2, p. 137-150Article in journal (Refereed)
    Abstract [en]

    One important step for assessing the quality of a test is to examine the reliability of test score interpretation. Which aspect of reliability is the most relevant depends on what type of test it is and how the scores are to be used. For criterion-referenced tests, and in particular certification tests, where students are classified into performance categories, primary focus need not be on the size of error but on the impact of this error on classification. This impact can be described in terms of classification consistency and classification accuracy. In this article selected methods from classical test theory for estimating classification consistency and classification accuracy were applied to the theory part of the Swedish driving licence test, a high-stakes criterion-referenced test which is rarely studied in terms of reliability of classification. The results for this particular test indicated a level of classification consistency that falls slightly short of the recommended level which is why lengthening the test should be considered. More evidence should also be gathered as to whether the placement of the cut-off score is appropriate since this has implications for the validity of classifications.

  • 195.
    Algers, Björn
    Umeå University, Faculty of Science and Technology, Department of Physics.
    Stereo Camera Calibration Accuracy in Real-time Car Angles Estimation for Vision Driver Assistance and Autonomous Driving2018Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The automotive safety company Veoneer are producers of high end driver visual assistance systems, but the knowledge about the absolute accuracy of their dynamic calibration algorithms that estimate the vehicle’s orientation is limited.

    In this thesis, a novel measurement system is proposed to be used in gathering reference data of a vehicle’s orientation as it is in motion, more specifically the pitch and roll angle of the vehicle. Focus has been to estimate how the uncertainty of the measurement system is affected by errors introduced during its construction, and to evaluate its potential in being a viable tool in gathering reference data for algorithm performance evaluation.

    The system consisted of three laser distance sensors mounted on the body of the vehicle, and a range of data acquisition sequences with different perturbations were performed by driving along a stretch of road in Linköping with weights loaded in the vehicle. The reference data were compared to camera system data where the bias of the calculated angles were estimated, along with the dynamic behaviour of the camera system algorithms. The experimental results showed that the accuracy of the system exceeded 0.1 degrees for both pitch and roll, but no conclusions about the bias of the algorithms could be drawn as there were systematic errors present in the measurements.

  • 196.
    Algesten, Grete
    Umeå University, Faculty of Science and Technology, Ecology and Environmental Science.
    Regulation of carbon dioxide emission from Swedish boreal lakes and the Gulf of Bothnia2005Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The global carbon cycle is subject to intense research, where sources and sinks for greenhouse gases, carbon dioxide in particular, are estimated for various systems and biomes. Lakes have previously been neglected in carbon balance estimations, but have recently been recognized to be significant net sources of CO2.

    This thesis estimates emission of carbon dioxide (CO2) from boreal lakes and factors regulating the CO2 saturation from field measurements of CO2 concentration along with a number of chemical, biological and physical parameters. Concentration of dissolved organic carbon (DOC) was found to be the most important factor for CO2 saturation in lake water, whereas climatic parameters such as precipitation, temperature and global radiation were less influential. All lakes were supersaturated with and, thus, sources of CO2. Sediment incubation experiments indicated that in-lake mineralization processes during summer stratification mainly occurred in the pelagial. Approximately 10% of the CO2 emitted from the lake surface was produced in epilimnetic sediments.

    The mineralization of DOC and emission of CO2 from freshwaters was calculated on a catchment basis for almost 80,000 lakes and 21 major catchments in Sweden, together with rates of sedimentation in lakes and export of organic carbon to the sea. The total export of terrestrial organic carbon to freshwaters could thereby be estimated and consequently also the importance of lakes for the withdrawal of organic carbon export from terrestrial sources to the sea. Lakes removed 30-80% of imported terrestrial organic carbon, and mineralization and CO2 emission were much more important than sedimentation of carbon. The carbon loss was closely related to water retention time, where catchments with short residence times (<1 year) had low carbon retentions, whereas in catchments with long residence times (>3 years) a majority of the imported TOC was removed in the lake systems.

    The Gulf of Bothnia was also studied in this thesis and found to be a net heterotrophic system, emitting large amounts of CO2 to the atmosphere on an annual basis. The rate of CO2 emission was depending on the balance between primary production and bacterial respiration, and the system was oscillating between being a source and a sink of CO2.

  • 197.
    Algesten, Grete
    et al.
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Brydsten, Lars
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Jonsson, Per
    Institute of Applied Environmental Research, Stockholm University, Stockholm, Sweden.
    Kortelainen, Pirkko
    Finnish Environment Institute, P.O. Box 140, FIN-00251, Helsinki, Finland.
    Löfgren, Stefan
    Department of Environmental Assessment, SLU, P.O. Box 7050, Uppsala, Sweden.
    Rahm, Lars
    Department of Water and Environmental Studies, Linköping University, SE-58183 Linköping, Sweden.
    Räike, Antti
    Finnish Environment Institute, P.O. Box 140, FIN-00251, Helsinki, Finland.
    Sobek, Sebastian
    Institute for Aquatic Sciences and Water Pollution Control, Swiss Federal Institute of Technology Zurich (ETH), Universitätsstr. 16, CH-8092 Zurich, Switzerland.
    Tranvik, Lars
    Department of Ecology and Evolution, EBC, Uppsala University, SE-752 36 Uppsala, Sweden.
    Wikner, Johan
    Umeå University, Faculty of Science and Technology, Umeå Marine Sciences Centre (UMF).
    Jansson, Mats
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Organic carbon budget for the Gulf of Bothnia2006In: Journal of Marine Systems, ISSN 0924-7963, E-ISSN 1879-1573, Vol. 63, no 3-4, p. 155-161Article in journal (Refereed)
    Abstract [en]

    We calculated input of organic carbon to the unproductive, brackish water basin of the Gulf of Bothnia from rivers, point sources and the atmosphere. We also calculated the net exchange of organic carbon between the Gulf of Bothnia and the adjacent marine system, the Baltic Proper. We compared the input with sinks for organic carbon; permanent incorporation in sediments and mineralization and subsequent evasion of CO2 to the atmosphere. The major fluxes were riverine input (1500 Gg C year− 1), exchange with the Baltic Proper (depending on which of several possible DOC concentration differences between the basins that was used in the calculation, the flux varied between an outflow of 466 and an input of 950 Gg C year 1), sediment burial (1100 Gg C year− 1) and evasion to the atmosphere (3610 Gg C year− 1). The largest single net flux was the emission of CO2 to the atmosphere, mainly caused by bacterial mineralization of organic carbon. Input and output did not match in our budget which we ascribe uncertainties in the calculation of the exchange of organic carbon between the Gulf of Bothnia and the Baltic Proper, and the fact that CO2 emission, which in our calculation represented 1 year (2002) may have been overestimated in comparison with long-term means. We conclude that net heterotrophy of the Gulf of Bothnia was due to input of organic carbon from both the catchment and from the Baltic Proper and that the future degree of net heterotrophy will be sensible to both catchment export of organic carbon and to the ongoing eutrophication of the Baltic Proper.

  • 198.
    Algesten, Grete
    et al.
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Wikner, Johan
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences. Umeå University, Faculty of Science and Technology, Umeå Marine Sciences Centre (UMF).
    Sobek, Sobek
    Department of Limnology, Evolutionary Biology Centre, Uppsala University, Uppsala, Sweden .
    Tranvik, Lars T.
    Department of Limnology, Evolutionary Biology Centre, Uppsala University, Uppsala, Sweden .
    Jansson, Mats
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Seasonal variation of CO2 saturation in the Gulf of Bothnia: Indications of marine net heterotrophy2004In: Global Biogeochemical Cycles, ISSN 0886-6236, E-ISSN 1944-9224, Vol. 18, p. 4021-4028Article in journal (Refereed)
    Abstract [en]

    Seasonal variation of pCO2 and primary and bacterioplankton production were measured in the Gulf of Bothnia during an annual cycle. Surface water was supersaturated with CO2 on an annual basis, indicating net heterotrophy and a source of CO2 to the atmosphere. However, the Gulf of Bothnia oscillated between being a sink and a source of CO2 over the studied period, largely decided by temporal variation in bacterial respiration (BR) and primary production (PP) in the water column above the pycnocline. The calculated annual respiration-production balance (BR-PP) was very similar to the estimated CO2 emission from the Gulf of Bothnia, which indicates that these processes were major determinants of the exchange of CO2 between water and atmosphere. The southern basin (the Bothnian Sea) had a lower net release of CO2 to the atmosphere than the northern Bothnian Bay (7.1 and 9.7 mmol C m−2 d−1, respectively), due to higher primary production, which to a larger extent balanced respiration in this basin.

  • 199. Alhayali, Amani
    et al.
    Tavelin, Staffan
    Umeå University, Faculty of Medicine, Department of Pharmacology and Clinical Neuroscience, Pharmacology.
    Velaga, Sitaram
    Dissolution and precipitation behavior of ternary solid dispersions of ezetimibe in biorelevant media2017In: Drug Development and Industrial Pharmacy, ISSN 0363-9045, E-ISSN 1520-5762, Vol. 43, no 1, p. 79-88Article in journal (Refereed)
    Abstract [en]

    The effects of different formulations and processes on inducing and maintaining the supersaturation of ternary solid dispersions of ezetimibe (EZ) in two biorelevant media fasted-state simulated intestinal fluid (FaSSIF) and fasted-state simulated gastric fluid (FaSSGF) at different temperatures (25 °C and 37 °C) were investigated in this work.

    Ternary solid dispersions of EZ were prepared by adding polymer PVP-K30 and surfactant poloxamer 188 using melt-quenching and spray-drying methods. The resulting solid dispersions were characterized using scanning electron microscopy, differential scanning calorimetry (DSC), modulated DSC, powder X-ray diffraction and Fourier transformation infrared spectroscopy. The dissolution of all the ternary solid dispersions was tested in vitro under non-sink conditions.

    All the prepared solid dispersions were amorphous in nature. In FaSSIF at 25 °C, the melt-quenched (MQ) solid dispersions of EZ were more soluble than the spray-dried (SD) solid dispersions and supersaturation was maintained. However, at 37 °C, rapid and variable precipitation behavior was observed for all the MQ and SD formulations. In FaSSGF, the melting method resulted in better solubility than the spray-drying method at both temperatures.

    Ternary solid dispersions show potential for improving solubility and supersaturation. However, powder dissolution experiments of these solid dispersions of EZ at 25 °C may not predict the supersaturation behavior at physiologically relevant temperatures.

  • 200.
    Al-Hayali, Asifa
    Umeå University, Faculty of Science and Technology, Department of Physics.
    Characterization of ion-irradiation-induced defects in graphite by Raman and Atomic Force Microscopy2013Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Graphite is an interesting prototype material for ion implantation studies because of the anisotropy in its physical and structural properties; In particular, due to the layered nature of the graphite lattice, the processes of amorphization and recrystallization (graphitization) of the implanted region are conceptually different from that observed in commonly studied materials. Since ion implantation provides a controlled method for the introduction of lattice defects which can be subsequently annealed, this technique provides fundamental information on the unique crystalline regrowth (graphitization)process of this highly anisotropic material. The structure of ion‐irradiated HOPG has also been studied, and drawing inspiration from this, the crystallite size is fundamental in these novel properties in carbon. The bombarded graphite (with H+ and He ions), diamagnetic graphite, were performed using a Renishaw Raman microscope with a 514.5 nm Ar‐ion laser. The work includes the following parts:

    1. Raman spectroscopy (measurements, spectra treatment with Origin and LabFit program, interpretation based on available literature).

    2. Atomic force microscopy, interpretation with the SPIP software.

    3. TRIM software simulation ion tracks in the sample.

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