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  • Publications
  • 2022-2022
  • English
  • Publikationer från Umeå universitet

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  • Open Access English
    Authors: 
    Eduardo Maia Paiva; Emil Thorin; Florian Schmidt;
    Publisher: Umeå universitet, Institutionen för tillämpad fysik och elektronik
    Country: Sweden

    Gaseous potassium (K) species play an important role in biomass combustion processes, and imaging techniques are powerful tools to investigate the related gas-phase chemistry. Here, laser absorption imaging of gaseous atomic K in flames is implemented using tunable diode laser absorption spectroscopy at 769.9 nm and a high-speed complementary metal oxide semiconductor (CMOS) camera recording at 30 kfps. Atomic K absorption spectra are acquired for each camera pixel in a field of view of 28 × 28 mm at a rate of 100 Hz. The technique is used to determine the spatial distribution of atomic K concentration during the conversion of potassium chloride (KCl) salt and wheat straw particles in a laminar premixed CH4/air flame with an image pixel resolution of up to 120 μm. Due to axisymmetry in setup geometry and, consequently, atomic K distributions, the radial atomic K concentration fields could be reconstructed by one-dimensional tomography. For the KCl sample, the K concentration field was in excellent agreement with previous point measurements. In the case of wheat straw, atomic K concentrations of around 3 ppm were observed in a cylindrical flame during devolatilization. In the char conversion phase, a spherical layer of atomic K, with concentrations reaching 25 ppm, was found within 5 mm of the particle surface, while the concentration rapidly decreased to sub-ppm levels along the vertical axis. In both cases, a thin (∼1 mm) layer without any atomic K was observed in close vicinity to the particle, suggesting that the potassium was initially not released in its atomic form.

  • Publication . Article . 2022
    Open Access English
    Authors: 
    Camilla Hällgren; Åsa Björk;
    Publisher: Umeå universitet, Institutionen för tillämpad utbildningsvetenskap
    Country: Sweden

    PurposeBut, so far, little is known about what this means to young people in their lives and how educators and others can support them. Most studies to date investigate digital technology use as a discrete phenomenon and few studies concern young people's identity practices in contexts, as they occur. In an increasingly digital world, where dependency on digital technologies continues this forms an urgent knowledge gap to bridge. In particular to guide educators and others, who support young people as they live and learn through interconnected spaces in and out of school. This conceptual paper is of importance to better understand how to bridge this gap.Design/methodology/approachThis conceptual paper takes identity, digital technology, young people and education as a combined starting point and suggests how to research young people's identity practices in and out of school. Today's young people form their identities in a world that is increasingly imbued by digital technologies. What is evident too is that these technologies and the use of them are not restricted to one single context. Rather, digital technologies mediate multiple contexts simultaneously – to an extent where they collapse. This means that school and leisure time, public and private, digital and analog, virtual and material, time and place, social contexts and audiences, through digital technology, merge in various ways in young people's identity practices and everyday life.FindingsThis conceptual paper is of importance to better understand how to bridge this gap. It addresses digital technology, identity, young people and education as a combined starting point to outline research questions.Research limitations/implicationsIt addresses identity, digital technology, young people and education as a combined starting point to outline research questions. The Guided Tour Technique and Social Media Research is suggested as possible methodologies for both ontologically and ethically sensitive, empirical research. The paper ends with concluding remarks on the relevance and significance of the proposed research approach.Originality/valueThe Guided Tour Technique and Social Media Research is suggested as possible methodologies for both ontologically and ethically sensitive, empirical research. The paper finishes with reflections on theory and potential advancement of new knowledge.

  • Open Access English
    Authors: 
    Per Jolbäck; Sebastian Mukka; Kristin Wetterling; Maizar Mohaddes; Anne Garland;
    Publisher: Umeå universitet, Ortopedi
    Country: Sweden

    Background and purpose: The sex of the surgeon has been proposed to be associated with a disparity in clinical outcomes after different surgical procedures. We investigated the association between surgeon–patient sex discordance and adverse events (AEs) and surgical AEs (SAEs) within 90 days after primary total hip arthroplasty (THA). We also investigated patient-reported satisfaction with surgical outcomes 1 year after the surgery.Patients and methods: We conducted a register-based cohort study including primary THAs performed due to osteoarthritis between 2008 and 2016 at 10 publicly managed hospitals in western Sweden. Hospital data was linked to the Swedish Arthroplasty Register and a regional patient register. Logistic regression models investigated discordant sex of patients and surgeons on AEs/SAEs and patient-reported satisfaction with the surgical outcome.Results: 11,993 primary THAs were included in the study. The proportion of AEs for the concordant group was 7.3% and for the discordant group 6.1%. For SAEs, the proportion was 5.0% for the concordant group and 4.3% for the discordant group. After adjustment the discordant group still had a lower likelihood of an AE or SAE than the concordant group: adjusted odds ratio (aOR) for AE (0.82, 95%CI 0.71–0.95) and for SAE (0.86, CI 0.72–0.99). No association was detected between patient-reported satisfaction and sex discordance.Conclusion: Sex discordance between surgeons and patients is linked to a decreased risk of an AE but not a lower level of patient-reported satisfaction with the surgical outcome.

  • Open Access English
    Authors: 
    Listia Rini; Joachim J. Schouteten; Ilona Faber; Kai-Brit Bechtold; Federico J. A. Perez-Cueto; Xavier Gellynck; Hans De Steur;
    Publisher: Umeå universitet, Institutionen för kost- och måltidsvetenskap
    Country: Sweden
    Project: EC | SMART PROTEIN (862957)

    Plant-based food (PBF) is on the rise as an alternative for animal-based food. Europe is leading in the market size compared with the global market. However, the high failure rate for new food products is challenging the success of new PBF in the market. This paper aims to unravel the key success factors (KSFs) from existing brands, contributing to the knowledge on how to achieve success in PBF market. Two subsequent studies employing online surveys were included, which targeted food expert participants. Study 1 focused on the collection of KSFs related to PBF brands utilizing the card sorting approach. Study 2 employed cluster analysis to further investigate the KSFs among different PBF brands. The findings identified six clusters of KSFs under the external and internal factors supporting the success of the PBF brands. Two (‘Consumer’ and ‘Trend’) and four (‘Ideology’, ‘Marketing strategy’, ‘Innovation management’, and ‘Management structure’) clusters were assigned into external and internal factors, respectively. Furthermore, cluster analysis identified four brand clusters: ‘Mature’, ‘Targeted’, ‘Newcomer’, and ‘Established but diversifying’ clusters. Each brand cluster utilized different KSFs into their strategies; however, both external and internal factors were applied, suggesting that there is no one-size-fits-all KSF to succeed in the market.

  • Open Access English
    Authors: 
    Michael C. Gilmore; Felipe Cava;
    Publisher: Umeå universitet, Molekylär Infektionsmedicin, Sverige (MIMS)
    Country: Sweden

    AbstractDuring growth and division, the bacterial cell wall peptidoglycan (PG) is remodelled, resulting in the liberation of PG muropeptides which are typically reinternalized and recycled. Bacteria belonging to the Rhizobiales and Rhodobacterales orders of the Alphaproteobacteria lack the muropeptide transporter AmpG, despite having other key PG recycling enzymes. Here, we show that an alternative transporter, YejBEF-YepA, takes over this role in the Rhizobiales phytopathogen Agrobacterium tumefaciens. Muropeptide import by YejBEF-YepA governs expression of the β-lactamase AmpC in A. tumefaciens, contributing to β-lactam resistance. However, we show that the absence of YejBEF-YepA causes severe cell wall defects that go far beyond lowered AmpC activity. Thus, contrary to previously established Gram-negative models, PG recycling is vital for cell wall integrity in A. tumefaciens. YepA is widespread in the Rhizobiales and Rhodobacterales, suggesting that YejBEF-YepA-mediated PG recycling could represent an important but overlooked aspect of cell wall biology in these bacteria.

  • Open Access English
    Authors: 
    Camila Emboava Lopes;
    Publisher: Umeå universitet, Institutionen för kultur- och medievetenskaper
    Country: Sweden

    The year 2020 was strange for Indigenous movements in Brazil. On-site gatherings were cancelled due to the outbreak of Covid-19. Indigenous movements, in connection with Indigenous media initiatives, aimed at occupying the screens instead. An abundance of live streams popped up on diverse social media platforms. During April 2020, online observations were carried out using an approach inspired by digital ethnography. This article offers a discussion about collecting research data within this changing context. The main aim is to reflect upon online observations as research practice and live streams as sources for scholarly investigation. Additionally, this paper discusses how to think about presence, place and temporality in the research context. 2020 var ett underligt år för urfolksrörelser i Brasilien. På grund av utbrottet av Covid-19 ställdes många av deras planerade sammankomster och träffar in. Istället höll urfolksgrupper massor av “liveströmmar” på sociala medieplattformar. Den här artikeln bygger på digital etnografi där sådana liveströmmar studeras. Online-observationerna genomfördes i april 2020. Artikeln bidrar med en diskussion om att samla in forskningsdata i sådana föränderliga sammanhang. Huvudsyftet är att reflektera över online-observationer som forskningspraxis och liveströmmar som källor för vetenskapliga undersökningar. Dessutom diskuteras hur forskare kan tänka om närvaro, plats och temporalitet i sådana kontexter.

  • Open Access English
    Authors: 
    Solveig Bollig;
    Publisher: Umeå universitet, Institutionen för språkstudier
    Country: Sweden

    The sagas of Icelanders contain a great wealth of personal names both of historical and fictional nature. Personal names function both as identifiers for individuals but also evoke associations that supersede the name’s lexical or identifying meaning, for example, cultural or social associations such as age, ethnicity, and ideology. This article examines personal names as a source within a source and appraises the use of literary and socio-onomastics in the context of the Íslendingasögur using the example of the elusive difference between “Icelanders” and “Norwegians” in the sagas. The onomastic analysis is based on seven shorter tales and explores the differences in personal names in Icelandic and Norwegian individuals. Based on the onomastic data gathered, this article concludes that there are certain regional differences in name-giving visible in the sagas and that saga authors either had authentic onomastic material at hand or tried to emulate realistic personal names. Islänningasagorna innehåller en stor mängd personnamn av både historisk och fiktiv karaktär. Personnamn fungerar både som identifierare för individer men väcker också associationer som överskuggar namnets lexikala eller identifierande betydelse, såsom kulturella eller sociala associationer som ålder, etnicitet och ideologi. I den här artikeln behandlas personnamn som en källa inom en källa. Även användningen av litterär onomastik och socioonomastik på Islänningasagorna evalueras genom att analysera den svårfångade skillnaden mellan ”islänningar” och ”norrmän” i sagorna. Den onomastiska analysen baseras på sju tåtar och utforskar skillnaderna i personnamn hos isländska och norska individer. Utifrån den onomastiska datan som samlats in drar artikeln slutsatsen att det finns vissa regionala skillnader i namngivning som är synliga i Islänningasagorna och att sagaförfattarna antingen hade autentiskt onomastiskt material till hands eller att de försökte efterlikna autentiska personnamn.

  • Open Access English
    Authors: 
    Dharmender K. Gahlot; Nayyer Taheri; Sheila MacIntyre;
    Publisher: Umeå universitet, Institutionen för molekylärbiologi (Teknisk-naturvetenskaplig fakultet)
    Country: Sweden

    Bacteria express different types of hair-like proteinaceous appendages on their cell surface known as pili or fimbriae. These filamentous structures are primarily involved in the adherence of bacteria to both abiotic and biotic surfaces for biofilm formation and/or virulence of non-pathogenic and pathogenic bacteria. In pathogenic bacteria, especially Gram-negative bacteria, fimbriae play a key role in bacteria–host interactions which are critical for bacterial invasion and infection. Fimbriae assembled by the Chaperone Usher pathway (CUP) are widespread within the Enterobacteriaceae, and their expression is tightly regulated by specific environmental stimuli. Genes essential for expression of CUP fimbriae are organised in small blocks/clusters, which are often located in proximity to other virulence genes on a pathogenicity island. Since these surface appendages play a crucial role in bacterial virulence, they have potential to be harnessed in vaccine development. This review covers the regulation of expression of CUP-assembled fimbriae in Gram-negative bacteria and uses selected examples to demonstrate both dedicated and global regulatory mechanisms.

  • Publication . Article . 2022
    Open Access English
    Authors: 
    Victor Falgas‐Ravry; Vincent Pfenninger;
    Publisher: Umeå universitet, Institutionen för matematik och matematisk statistik
    Country: Sweden

    A random graph model on a host graph (Formula presented.) is said to be 1-independent if for every pair of vertex-disjoint subsets (Formula presented.) of (Formula presented.), the state of edges (absent or present) in (Formula presented.) is independent of the state of edges in (Formula presented.). For an infinite connected graph (Formula presented.), the 1-independent critical percolation probability (Formula presented.) is the infimum of the (Formula presented.) such that every 1-independent random graph model on (Formula presented.) in which each edge is present with probability at least (Formula presented.) almost surely contains an infinite connected component. Balister and Bollobás observed in 2012 that (Formula presented.) tends to a limit in (Formula presented.) as (Formula presented.), and they asked for the value of this limit. We make progress on a related problem by showing that (Formula presented.) In fact, we show that the equality above remains true if the sequence of complete graphs (Formula presented.) is replaced by a sequence of weakly pseudorandom graphs on (Formula presented.) vertices with average degree (Formula presented.). We conjecture the answer to Balister and Bollobás's question is also (Formula presented.).

  • Open Access English
    Authors: 
    Cecilia S. Engdahl; Chinmay V. Tikhe; George Dimopoulos;
    Publisher: W. Harry Feinstone Department of Molecular Microbiology and Immunology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD, USA
    Country: Sweden

    AbstractVector control plays a key role in reducing the public health burden of mosquito-borne diseases. Today’s vector control strategies largely rely on synthetic insecticides that can have a negative environmental impact when applied outdoors and often become inefficient because of the mosquitoes’ ability to develop resistance. An alternative and promising approach to circumvent these challenges involves the implementation of insecticides derived from nature (biopesticides) for vector control. Biopesticides can constitute naturally occurring organisms or substances derived from them that have lifespan-shortening effects on disease vectors such as mosquitoes. Here we present the discovery and evaluation of natural product-based biological control agents that can potentially be developed into biopesticides for mosquito control. We screened a natural product collection comprising 390 compounds and initially identified 26 molecules with potential ability to kill the larval stages of the yellow fever mosquito Aedes aegypti, which is responsible for transmitting viruses such as dengue, Zika, chikungunya and yellow fever. Natural products identified as hits in the screen were further evaluated for their suitability for biopesticide development. We show that a selection of the natural product top hits, bactobolin, maytansine and ossamycin, also killed the larval stages of the malaria-transmitting mosquito Anopheles gambiae as well as the adult form of both species. We have further explored the usefulness of crude extracts and preparations from two of the best candidates’ sources (organisms of origin) for mosquitocidal activity, that is extracts from the two bacteria Burkholderia thailandensis and Streptomyces hygroscopicus var. ossamyceticus. Graphical abstract

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1,753 Research products, page 1 of 176
  • Open Access English
    Authors: 
    Eduardo Maia Paiva; Emil Thorin; Florian Schmidt;
    Publisher: Umeå universitet, Institutionen för tillämpad fysik och elektronik
    Country: Sweden

    Gaseous potassium (K) species play an important role in biomass combustion processes, and imaging techniques are powerful tools to investigate the related gas-phase chemistry. Here, laser absorption imaging of gaseous atomic K in flames is implemented using tunable diode laser absorption spectroscopy at 769.9 nm and a high-speed complementary metal oxide semiconductor (CMOS) camera recording at 30 kfps. Atomic K absorption spectra are acquired for each camera pixel in a field of view of 28 × 28 mm at a rate of 100 Hz. The technique is used to determine the spatial distribution of atomic K concentration during the conversion of potassium chloride (KCl) salt and wheat straw particles in a laminar premixed CH4/air flame with an image pixel resolution of up to 120 μm. Due to axisymmetry in setup geometry and, consequently, atomic K distributions, the radial atomic K concentration fields could be reconstructed by one-dimensional tomography. For the KCl sample, the K concentration field was in excellent agreement with previous point measurements. In the case of wheat straw, atomic K concentrations of around 3 ppm were observed in a cylindrical flame during devolatilization. In the char conversion phase, a spherical layer of atomic K, with concentrations reaching 25 ppm, was found within 5 mm of the particle surface, while the concentration rapidly decreased to sub-ppm levels along the vertical axis. In both cases, a thin (∼1 mm) layer without any atomic K was observed in close vicinity to the particle, suggesting that the potassium was initially not released in its atomic form.

  • Publication . Article . 2022
    Open Access English
    Authors: 
    Camilla Hällgren; Åsa Björk;
    Publisher: Umeå universitet, Institutionen för tillämpad utbildningsvetenskap
    Country: Sweden

    PurposeBut, so far, little is known about what this means to young people in their lives and how educators and others can support them. Most studies to date investigate digital technology use as a discrete phenomenon and few studies concern young people's identity practices in contexts, as they occur. In an increasingly digital world, where dependency on digital technologies continues this forms an urgent knowledge gap to bridge. In particular to guide educators and others, who support young people as they live and learn through interconnected spaces in and out of school. This conceptual paper is of importance to better understand how to bridge this gap.Design/methodology/approachThis conceptual paper takes identity, digital technology, young people and education as a combined starting point and suggests how to research young people's identity practices in and out of school. Today's young people form their identities in a world that is increasingly imbued by digital technologies. What is evident too is that these technologies and the use of them are not restricted to one single context. Rather, digital technologies mediate multiple contexts simultaneously – to an extent where they collapse. This means that school and leisure time, public and private, digital and analog, virtual and material, time and place, social contexts and audiences, through digital technology, merge in various ways in young people's identity practices and everyday life.FindingsThis conceptual paper is of importance to better understand how to bridge this gap. It addresses digital technology, identity, young people and education as a combined starting point to outline research questions.Research limitations/implicationsIt addresses identity, digital technology, young people and education as a combined starting point to outline research questions. The Guided Tour Technique and Social Media Research is suggested as possible methodologies for both ontologically and ethically sensitive, empirical research. The paper ends with concluding remarks on the relevance and significance of the proposed research approach.Originality/valueThe Guided Tour Technique and Social Media Research is suggested as possible methodologies for both ontologically and ethically sensitive, empirical research. The paper finishes with reflections on theory and potential advancement of new knowledge.

  • Open Access English
    Authors: 
    Per Jolbäck; Sebastian Mukka; Kristin Wetterling; Maizar Mohaddes; Anne Garland;
    Publisher: Umeå universitet, Ortopedi
    Country: Sweden

    Background and purpose: The sex of the surgeon has been proposed to be associated with a disparity in clinical outcomes after different surgical procedures. We investigated the association between surgeon–patient sex discordance and adverse events (AEs) and surgical AEs (SAEs) within 90 days after primary total hip arthroplasty (THA). We also investigated patient-reported satisfaction with surgical outcomes 1 year after the surgery.Patients and methods: We conducted a register-based cohort study including primary THAs performed due to osteoarthritis between 2008 and 2016 at 10 publicly managed hospitals in western Sweden. Hospital data was linked to the Swedish Arthroplasty Register and a regional patient register. Logistic regression models investigated discordant sex of patients and surgeons on AEs/SAEs and patient-reported satisfaction with the surgical outcome.Results: 11,993 primary THAs were included in the study. The proportion of AEs for the concordant group was 7.3% and for the discordant group 6.1%. For SAEs, the proportion was 5.0% for the concordant group and 4.3% for the discordant group. After adjustment the discordant group still had a lower likelihood of an AE or SAE than the concordant group: adjusted odds ratio (aOR) for AE (0.82, 95%CI 0.71–0.95) and for SAE (0.86, CI 0.72–0.99). No association was detected between patient-reported satisfaction and sex discordance.Conclusion: Sex discordance between surgeons and patients is linked to a decreased risk of an AE but not a lower level of patient-reported satisfaction with the surgical outcome.

  • Open Access English
    Authors: 
    Listia Rini; Joachim J. Schouteten; Ilona Faber; Kai-Brit Bechtold; Federico J. A. Perez-Cueto; Xavier Gellynck; Hans De Steur;
    Publisher: Umeå universitet, Institutionen för kost- och måltidsvetenskap
    Country: Sweden
    Project: EC | SMART PROTEIN (862957)

    Plant-based food (PBF) is on the rise as an alternative for animal-based food. Europe is leading in the market size compared with the global market. However, the high failure rate for new food products is challenging the success of new PBF in the market. This paper aims to unravel the key success factors (KSFs) from existing brands, contributing to the knowledge on how to achieve success in PBF market. Two subsequent studies employing online surveys were included, which targeted food expert participants. Study 1 focused on the collection of KSFs related to PBF brands utilizing the card sorting approach. Study 2 employed cluster analysis to further investigate the KSFs among different PBF brands. The findings identified six clusters of KSFs under the external and internal factors supporting the success of the PBF brands. Two (‘Consumer’ and ‘Trend’) and four (‘Ideology’, ‘Marketing strategy’, ‘Innovation management’, and ‘Management structure’) clusters were assigned into external and internal factors, respectively. Furthermore, cluster analysis identified four brand clusters: ‘Mature’, ‘Targeted’, ‘Newcomer’, and ‘Established but diversifying’ clusters. Each brand cluster utilized different KSFs into their strategies; however, both external and internal factors were applied, suggesting that there is no one-size-fits-all KSF to succeed in the market.

  • Open Access English
    Authors: 
    Michael C. Gilmore; Felipe Cava;
    Publisher: Umeå universitet, Molekylär Infektionsmedicin, Sverige (MIMS)
    Country: Sweden

    AbstractDuring growth and division, the bacterial cell wall peptidoglycan (PG) is remodelled, resulting in the liberation of PG muropeptides which are typically reinternalized and recycled. Bacteria belonging to the Rhizobiales and Rhodobacterales orders of the Alphaproteobacteria lack the muropeptide transporter AmpG, despite having other key PG recycling enzymes. Here, we show that an alternative transporter, YejBEF-YepA, takes over this role in the Rhizobiales phytopathogen Agrobacterium tumefaciens. Muropeptide import by YejBEF-YepA governs expression of the β-lactamase AmpC in A. tumefaciens, contributing to β-lactam resistance. However, we show that the absence of YejBEF-YepA causes severe cell wall defects that go far beyond lowered AmpC activity. Thus, contrary to previously established Gram-negative models, PG recycling is vital for cell wall integrity in A. tumefaciens. YepA is widespread in the Rhizobiales and Rhodobacterales, suggesting that YejBEF-YepA-mediated PG recycling could represent an important but overlooked aspect of cell wall biology in these bacteria.

  • Open Access English
    Authors: 
    Camila Emboava Lopes;
    Publisher: Umeå universitet, Institutionen för kultur- och medievetenskaper
    Country: Sweden

    The year 2020 was strange for Indigenous movements in Brazil. On-site gatherings were cancelled due to the outbreak of Covid-19. Indigenous movements, in connection with Indigenous media initiatives, aimed at occupying the screens instead. An abundance of live streams popped up on diverse social media platforms. During April 2020, online observations were carried out using an approach inspired by digital ethnography. This article offers a discussion about collecting research data within this changing context. The main aim is to reflect upon online observations as research practice and live streams as sources for scholarly investigation. Additionally, this paper discusses how to think about presence, place and temporality in the research context. 2020 var ett underligt år för urfolksrörelser i Brasilien. På grund av utbrottet av Covid-19 ställdes många av deras planerade sammankomster och träffar in. Istället höll urfolksgrupper massor av “liveströmmar” på sociala medieplattformar. Den här artikeln bygger på digital etnografi där sådana liveströmmar studeras. Online-observationerna genomfördes i april 2020. Artikeln bidrar med en diskussion om att samla in forskningsdata i sådana föränderliga sammanhang. Huvudsyftet är att reflektera över online-observationer som forskningspraxis och liveströmmar som källor för vetenskapliga undersökningar. Dessutom diskuteras hur forskare kan tänka om närvaro, plats och temporalitet i sådana kontexter.

  • Open Access English
    Authors: 
    Solveig Bollig;
    Publisher: Umeå universitet, Institutionen för språkstudier
    Country: Sweden

    The sagas of Icelanders contain a great wealth of personal names both of historical and fictional nature. Personal names function both as identifiers for individuals but also evoke associations that supersede the name’s lexical or identifying meaning, for example, cultural or social associations such as age, ethnicity, and ideology. This article examines personal names as a source within a source and appraises the use of literary and socio-onomastics in the context of the Íslendingasögur using the example of the elusive difference between “Icelanders” and “Norwegians” in the sagas. The onomastic analysis is based on seven shorter tales and explores the differences in personal names in Icelandic and Norwegian individuals. Based on the onomastic data gathered, this article concludes that there are certain regional differences in name-giving visible in the sagas and that saga authors either had authentic onomastic material at hand or tried to emulate realistic personal names. Islänningasagorna innehåller en stor mängd personnamn av både historisk och fiktiv karaktär. Personnamn fungerar både som identifierare för individer men väcker också associationer som överskuggar namnets lexikala eller identifierande betydelse, såsom kulturella eller sociala associationer som ålder, etnicitet och ideologi. I den här artikeln behandlas personnamn som en källa inom en källa. Även användningen av litterär onomastik och socioonomastik på Islänningasagorna evalueras genom att analysera den svårfångade skillnaden mellan ”islänningar” och ”norrmän” i sagorna. Den onomastiska analysen baseras på sju tåtar och utforskar skillnaderna i personnamn hos isländska och norska individer. Utifrån den onomastiska datan som samlats in drar artikeln slutsatsen att det finns vissa regionala skillnader i namngivning som är synliga i Islänningasagorna och att sagaförfattarna antingen hade autentiskt onomastiskt material till hands eller att de försökte efterlikna autentiska personnamn.

  • Open Access English
    Authors: 
    Dharmender K. Gahlot; Nayyer Taheri; Sheila MacIntyre;
    Publisher: Umeå universitet, Institutionen för molekylärbiologi (Teknisk-naturvetenskaplig fakultet)
    Country: Sweden

    Bacteria express different types of hair-like proteinaceous appendages on their cell surface known as pili or fimbriae. These filamentous structures are primarily involved in the adherence of bacteria to both abiotic and biotic surfaces for biofilm formation and/or virulence of non-pathogenic and pathogenic bacteria. In pathogenic bacteria, especially Gram-negative bacteria, fimbriae play a key role in bacteria–host interactions which are critical for bacterial invasion and infection. Fimbriae assembled by the Chaperone Usher pathway (CUP) are widespread within the Enterobacteriaceae, and their expression is tightly regulated by specific environmental stimuli. Genes essential for expression of CUP fimbriae are organised in small blocks/clusters, which are often located in proximity to other virulence genes on a pathogenicity island. Since these surface appendages play a crucial role in bacterial virulence, they have potential to be harnessed in vaccine development. This review covers the regulation of expression of CUP-assembled fimbriae in Gram-negative bacteria and uses selected examples to demonstrate both dedicated and global regulatory mechanisms.

  • Publication . Article . 2022
    Open Access English
    Authors: 
    Victor Falgas‐Ravry; Vincent Pfenninger;
    Publisher: Umeå universitet, Institutionen för matematik och matematisk statistik
    Country: Sweden

    A random graph model on a host graph (Formula presented.) is said to be 1-independent if for every pair of vertex-disjoint subsets (Formula presented.) of (Formula presented.), the state of edges (absent or present) in (Formula presented.) is independent of the state of edges in (Formula presented.). For an infinite connected graph (Formula presented.), the 1-independent critical percolation probability (Formula presented.) is the infimum of the (Formula presented.) such that every 1-independent random graph model on (Formula presented.) in which each edge is present with probability at least (Formula presented.) almost surely contains an infinite connected component. Balister and Bollobás observed in 2012 that (Formula presented.) tends to a limit in (Formula presented.) as (Formula presented.), and they asked for the value of this limit. We make progress on a related problem by showing that (Formula presented.) In fact, we show that the equality above remains true if the sequence of complete graphs (Formula presented.) is replaced by a sequence of weakly pseudorandom graphs on (Formula presented.) vertices with average degree (Formula presented.). We conjecture the answer to Balister and Bollobás's question is also (Formula presented.).

  • Open Access English
    Authors: 
    Cecilia S. Engdahl; Chinmay V. Tikhe; George Dimopoulos;
    Publisher: W. Harry Feinstone Department of Molecular Microbiology and Immunology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD, USA
    Country: Sweden

    AbstractVector control plays a key role in reducing the public health burden of mosquito-borne diseases. Today’s vector control strategies largely rely on synthetic insecticides that can have a negative environmental impact when applied outdoors and often become inefficient because of the mosquitoes’ ability to develop resistance. An alternative and promising approach to circumvent these challenges involves the implementation of insecticides derived from nature (biopesticides) for vector control. Biopesticides can constitute naturally occurring organisms or substances derived from them that have lifespan-shortening effects on disease vectors such as mosquitoes. Here we present the discovery and evaluation of natural product-based biological control agents that can potentially be developed into biopesticides for mosquito control. We screened a natural product collection comprising 390 compounds and initially identified 26 molecules with potential ability to kill the larval stages of the yellow fever mosquito Aedes aegypti, which is responsible for transmitting viruses such as dengue, Zika, chikungunya and yellow fever. Natural products identified as hits in the screen were further evaluated for their suitability for biopesticide development. We show that a selection of the natural product top hits, bactobolin, maytansine and ossamycin, also killed the larval stages of the malaria-transmitting mosquito Anopheles gambiae as well as the adult form of both species. We have further explored the usefulness of crude extracts and preparations from two of the best candidates’ sources (organisms of origin) for mosquitocidal activity, that is extracts from the two bacteria Burkholderia thailandensis and Streptomyces hygroscopicus var. ossamyceticus. Graphical abstract

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