miun.sePublications
Change search
Refine search result
3456789 251 - 300 of 436
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Rows per page
  • 5
  • 10
  • 20
  • 50
  • 100
  • 250
Sort
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
Select
The maximal number of hits you can export is 250. When you want to export more records please use the 'Create feeds' function.
  • 251.
    Liu, Rong
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Berglund, Per
    Högberg, Hans-Erik
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Preparation of the four stereoisomers of 3-bromo-2-butanol or their acetates via lipase-catalysed resolutions of the racemates derived from dl- or meso-2,3-butanediol2005In: Tetrahedron: asymmetry, ISSN 0957-4166, E-ISSN 1362-511X, Vol. 16, no 15, p. 2607-2611Article in journal (Refereed)
    Abstract [en]

    The four stereoisomeric 3-bromo-2-butanols and/or their acetates were prepared via lipase-catalysed kinetic resolution by hydrolyses of the acetates of the (+/-)-syn- and (+/-)-anti-3-bromo-2-butanols, or via esterifications of the alc hols. The diastereomeric bromoacetates were obtained by syntheses from the dl- and meso-2,3-butanediols, respectively. On a preparative scale, the four stereoisomers, either as the free alcohols or as their acetates, were obtained in > 95% ee, and in 35-40% yield (based on the starting racemates).

  • 252.
    Liu, Rong
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Högberg, Hans-Erik
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Chemoenzymatic preparation of (2S, 3S)- and (2R, 3R)-2,3-butanediols and their esters from mixtures of d,l- and meso-diols2001In: Tetrahedron: Asymmetry, ISSN 0957-4166, Vol. 12, no 5, p. 771-778Article in journal (Refereed)
    Abstract [en]

    An efficient method of preparing the pure enantiomers of 2,3-butanediol front commercially available mixtures of the d,l- and meso-isomers was developed. It furnished (2S,3S)-2.3-butanediol with > 99% e.e. and a >9.5/0.5 diastereomeric ratio and (2R,3R)-2,3-butanediol in 95% e.e. and >9.5/<5 diastereomeric ratio.

  • 253. Liénard, Marjorie A
    et al.
    Strandh, Maria
    Hedenström, Erik
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences, Engineering and Mathematics.
    Johansson, Tomas
    Löfstedt, Christer
    Key biosynthetic gene subfamily recruited for pheromone production prior to the extensive radiation of Lepidoptera2008In: BMC Evolutionary Biology, ISSN 1471-2148, E-ISSN 1471-2148, Vol. 8, no 270Article in journal (Refereed)
    Abstract [en]

    Background Moths have evolved highly successful mating systems, relying on species-specific mixtures of sex pheromone components for long-distance mate communication. Acyl-CoA desaturases are key enzymes in the biosynthesis of these compounds and to a large extent they account for the great diversity of pheromone structures in Lepidoptera. A novel desaturase gene subfamily that displays Δ11 catalytic activities has been highlighted to account for most of the unique pheromone signatures of the taxonomically advanced ditrysian species. To assess the mechanisms driving pheromone evolution, information is needed about the signalling machinery of primitive moths. The currant shoot borer, Lampronia capitella, is the sole reported primitive non-ditrysian moth known to use unsaturated fatty-acid derivatives as sex-pheromone. By combining biochemical and molecular approaches we elucidated the biosynthesis paths of its main pheromone component, the (Z,Z)-9,11-tetradecadien-1-ol and bring new insights into the time point of the recruitment of the key Δ11-desaturase gene subfamily in moth pheromone biosynthesis. Results The reconstructed evolutionary tree of desaturases evidenced two ditrysian-specific lineages (the Δ11 and Δ9 (18C>16C)) to have orthologs in the primitive moth L. capitella despite being absent in Diptera and other insect genomes. Four acyl-CoA desaturase cDNAs were isolated from the pheromone gland, three of which are related to Δ9-desaturases whereas the fourth cDNA clusters with Δ11-desaturases. We demonstrated that this transcript (Lca-KPVQ) exclusively accounts for both steps of desaturation involved in pheromone biosynthesis. This enzyme possesses a Z11-desaturase activity that allows transforming the palmitate precursor (C16:0) into (Z)-11-hexadecenoic acid and the (Z)-9-tetradecenoic acid into the conjugated intermediate (Z,Z)-9,11-tetradecadienoic acid. Conclusion The involvement of a single Z11-desaturase in pheromone biosynthesis of a non-ditrysian moth species, supports that the duplication event leading to the origin of the Lepidoptera-specific Δ11-desaturase gene subfamily took place before radiation of ditrysian moths and their divergence from other heteroneuran lineages. Our findings uncover that this novel class of enzymes affords complex combinations of unique unsaturated fatty acyl-moieties of variable chain-lengths, regio- and stereo-specificities since early in moth history and contributes a notable innovation in the early evolution of moth-pheromones.

  • 254.
    Lundgren, Anders
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Internal catalytic bed in a staged fluidized bed2015Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    In this work the purpose is to investigate whether a staged fluidized bed can maintain its hydrodynamics while introducing a stationary internal catalytic bed in the upper fluidized bed. To accomplish this a literature study has been made. This resulted in finding the key parameters of gas and bed material mass flow that determines if a fluidized bed is formed or not. The literature study also showed a positive catalytic effect with decreased size of the catalytic particles. The experimental setup was designed to check for the two anomalies where the gasifying velocity and the bed material mass flow rate was as high and low as possible. A middle ground was used as another point of interest. The objective was then to incrementally minimize the particle size of the internal catalytic bed. The results showed that the internal catalytic bed could be present in the staged fluidized bed while maintaining the fluid dynamics, but only if the gas velocity was high enough. The produced syngas with the catalytic bed present did not show any results that indicates if the effect was positive or not.

  • 255. Lundh, Mårten
    et al.
    Nordin, Ove
    Hedenström, Erik
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Högberg, Hans-Erik
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Enzyme Catalysed Irreversible Transesterifications with Vinyl Acetate: Are they really Irreversible?1995In: Tetrahedron: Asymmetry, ISSN 0957-4166, Vol. 6, no 9, p. 2237-2244Article in journal (Refereed)
  • 256. Lundh, Mårten
    et al.
    Smitt, Olof
    Hedenström, Erik
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Sex Pheromone of Pine Sawflies: Enantioselective Lipase Catalysed Transesterification of erythro-3,7-Dimethylpentadecan-2-ol, Diprionol1996In: Tetrahedron: Asymmetry, ISSN 0957-4166, Vol. 7, no 11, p. 3277-3284Article in journal (Refereed)
  • 257.
    Lundström, Ulla
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Bain, DC
    Taylor, AF
    Van Hees, PA
    Geibe, Christine E
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Holmström, Sara J
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Melkerud, PA
    Finlay, R
    Jones, DL
    Nyberg, L
    Gustafsson, JP
    Riise, G
    Tau Strand, L
    Effects of acidification and its mitigation with lime and wood ash on forest soil processes in southern Sweden: A Joint Multidisciplinary Study2003In: Water , Air and Soil Pollution: Focus, ISSN 1567-7230, Vol. 3, no 4, p. 167-188Article in journal (Refereed)
  • 258.
    Lundström, Ulla
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Bain, D.C.
    Taylor, A.F.S.
    Van Hees, P.A.W.
    Effects of acidifiaction and its mitigation with lime and wood ash on forest soil processes: a review2003In: Water, Air, & Soil Pollution: Focus, ISSN 1567-7230, Vol. 3, no 4, p. 5-28Article in journal (Refereed)
  • 259.
    Lundström, Ulla S
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Norström, Sara H
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Vestin, Jenny L K
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Essén, Sofia A
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Bylund, Dan
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Dissolved Organic Matter Dynamics of Soil and Stream Water in a Catchment Area, Keynote speaker2006Conference paper (Other scientific)
  • 260.
    Lundström, Ulla
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    van Breemen, N.
    Bain, D. C.
    The podzolization process. A reveiw.2000In: Geoderma, ISSN 0016-7061, Vol. 94, no 2-4, p. 91-107Article, review/survey (Refereed)
    Abstract [en]

    This paper reviews the major mechanisms proposed to explain podzolization. These include the production of organic acids that form soluble complexes with aluminium/iron thereby enhancing weathering, followed by illuviation by precipitation/adsorption processes occurring at greater depth. Precipitation of aluminium and iron is explained by decreasing solubility of increasingly metal-rich complexes, or by microbial degradation of the organic ligand. We also discuss proposed role of inorganic hydroxy-aluminium-silicate sols in podzolization. The paper is introductory to a multidisciplinary study of podzolization performed in the Nordic Countries presented in this volume.

  • 261.
    Lundström, Ulla
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    van Breemen, N.
    Bain, D. C.
    van Hees, P. A. W.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Gielser, R.
    Gustafsson, J. P.
    Ilvesniemi, H.
    Karltun, E
    Melkerud, P. A.
    Olsson, M.
    Riise, G.
    Wahlberg, O.
    Bergelin, A.
    Bishop, K.
    Finlay, R.
    Advances in understanding the podzolization process resulting from a multidisciplinary study of three coniferous forest soils in the Nordic Countries2000In: Geoderma, ISSN 0016-7061, Vol. 94, no 2-4, p. 335-353Article in journal (Refereed)
  • 262. Lyytikäinen-Saarenmaa, P
    et al.
    Anderbrant, O
    Löfqvist, J
    Hedenström, Erik
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Högberg, Hans-Erik
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Monitoring European pine sawfly population density with pheromone traps in young pine plantations1999In: Forest Ecology and Management, ISSN 0378-1127, Vol. 124, no 2-3, p. 113-121Article in journal (Refereed)
  • 263. Lyytikäinen-Saarenmaa, P
    et al.
    Varama, M
    Anderbrant, O
    Kukkola, M
    Hedenström, Erik
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Högberg, Hans-Erik
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Predicting Pine Sawfly Population Densities and Subsequent Defolation with Pheromone Traps2001In: Integrated management and dynamics of forest defoliating insects, 2001, p. 108-116Conference paper (Refereed)
  • 264. Lyytikäinen-Saarenmaa, P.
    et al.
    Varama, M.
    Anderbrant, O.
    Kukkola, M.
    Hedenström, Erik
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Högberg, Hans-Erik
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Predicting pine sawfly population densities and subsequent defoliation with pheromone traps2001In: Proceedings. Integrated management and dynamics of forest defoliating insects, Victoria, Canada, 15-19 August 1999, 2001, p. 108-116Conference paper (Refereed)
  • 265.
    Lyytikäinen-Saarenmaa, P
    et al.
    Department of Applied Biology, University of Helsinki, Helsinki, Finland.
    Varama, M
    Finnish Forest Research Institute, Vantaa Research Centre, Vantaa, Finland.
    Anderbrant, O
    Department of Ecology, Lund University, Ecology Building, Lund.
    Kukkola, M
    Finnish Forest Research Institute, Vantaa Research Centre, Vantaa, Finland.
    Kokkonen, A.-M.
    Finnish Forest Research Institute, Vantaa Research Centre, Vantaa, Finland.
    Hedenström, Erik
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Högberg, Hans-Erik
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Monitoring the European pine sawfly with pheromone traps in maturing Scots pine stands2006In: Agricultural and Forest Entomology, ISSN 1461-9555, Vol. 8, no 1, p. 7-15Article in journal (Refereed)
    Abstract [en]

    1. During 1989-93, field studies were conducted in Finland to develop a method based on pheromone traps to monitor and forecast population levels of the European pine sawfly (Neodiprion sertifer Geoffr.) and tree defoliation. 2. Three traps per site were baited with 100 μg of the N. sertifer sex pheromone, the acetate ester of (2S,3S,7S)-3,7-dimethyl-2-pentadecanol (diprionol), in maturing pine stands in southern and central Finland. In addition, three different dosages (1, 10 and 100 μg) of the pheromone were tested in 1991-92. 3. The highest number of males was observed in traps baited with the highest dose. On average, there was a 10-fold increase in trap catch between lure doses. 4. Density of overwintering eggs was used to evaluate the effectiveness of pheromone traps in predicting sawfly populations. The proportion of healthy overwintering eggs was determined each year. A model based on the number of current shoots on sample trees, diameter at breast height and tree height was formulated to estimate eggs per hectare. 5. Linear regression analysis produced high coefficients of determination between number of males in traps and density of total eggs in the subsequent generation, when populations were at peak densities. The relationships were not significant for low population densities. The results indicate a risk of moderate defoliation when the seasonal trap catch is 800-1000 males per trap or higher.

  • 266.
    M, Yu
    et al.
    Department of Chemistry, Merkert Chemistry Center, Boston College, Chestnut Hill, MA 02467, United States.
    Ibrahem, Ismail
    Boston Coll, Merkert Chem Ctr, Dept Chem, Chestnut Hill, MA 02467 USA.
    Hasegawa, M
    Department of Chemistry, Merkert Chemistry Center, Boston College, Chestnut Hill, MA 02467, United States.
    Schrock, R.
    Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA 02139, United States.
    Hoveyda, H
    Department of Chemistry, Merkert Chemistry Center, Boston College, Chestnut Hill, MA 02467, United States.
    Enol Ethers as Substrates for Efficient Z- and Enantioselective Ring-Opening/Cross-Metathesis Reactions Promoted by Stereogenic-at-Mo Complexes; Utility in Chemical Synthesis and Mechanistic Attributes2012In: Journal of the American Chemical Society, ISSN 0002-7863, E-ISSN 1520-5126, Vol. 134, no 5, p. 2788-2799Article in journal (Refereed)
    Abstract [en]

    The first examples of catalytic enantioselective ring-opening/cross- metathesis (EROCM) reactions that involve enol ethers are reported. Specifically, we demonstrate that catalytic EROCM of several oxa-and azabicycles, cyclobutenes and a cyclopropene with an alkyl-or aryl-substituted enol ether proceed readily in the presence of a stereogenic-at-Mo monopyrrolide-monoaryloxide. In some instances, as little as 0.15 mol % of the catalytically active alkylidene is sufficient to promote complete conversion within 10 min. The desired products are formed in up to 90% yield and >99:1 enantiomeric ratio (er) with the disubstituted enol ether generated in >90% Z selectivity. The enol ether of the enantiomerically enriched products can be easily differentiated from the terminal alkene through a number of functionalization procedures that lead to the formation of useful intermediates for chemical synthesis (e.g., efficient acid hydrolysis to afford the enantiomerically enriched carboxaldehyde). In certain cases, enantioselectivity is strongly dependent on enol ether concentration: larger equivalents of the cross partner leads to the formation of products of high enantiomeric purity (versus near racemic products with one equivalent). The length of reaction time can be critical to product enantiomeric purity; high enantioselectivity in reactions that proceed to >98% conversion in as brief a reaction time as 30 s can be nearly entirely eroded within 30 min. Mechanistic rationale that accounts for the above characteristics of the catalytic process is provided. © 2012 American Chemical Society.

  • 267.
    Ma, Guangning
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Afewerki, Samson
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Deiana, L.
    Department of Organic Chemistry, Arrhenius Laboratory, Stockholm University, Sweden .
    Palo-Nieto, C.
    Department of Organic Chemistry, Arrhenius Laboratory, Stockholm University, Sweden .
    Liu, L.
    Berzelii Center EXSELENT, Stockholm University, Sweden .
    Sun, J.
    Berzelii Center EXSELENT, Stockholm University, Sweden .
    Ibrahem, Ismail
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Córdova, Armando
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    A palladium/chiral amine co-catalyzed enantioselective dynamic cascade reaction: Synthesis of polysubstituted carbocycles with a quaternary carbon stereocenter2013In: Angewandte Chemie International Edition, ISSN 1433-7851, E-ISSN 1521-3773, Vol. 52, no 23, p. 6050-6054Article in journal (Refereed)
    Abstract [en]

    Polysubstituted 5- and 6-membered carbocycles were synthesized by the title reaction. The one-pot dynamic relay process generates four new stereocenters, including a quaternary carbon center, in a highly enantioselective fashion (99.5:0.5→99:0.5 e.r.) by using a simple combination of palladium and chiral amine co-catalysts. 

  • 268.
    Ma, Guangning
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences, Engineering and Mathematics.
    Bartoszewicz, Agnieszka
    Stockholm Univ, Arrhenius Lab, Dept Organ Chem, SE-10691 Stockholm, Sweden .
    Ibrahem, Ismail
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences, Engineering and Mathematics.
    Córdova, Armando
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences, Engineering and Mathematics.
    Highly Enantioselective Co-Catalytic Direct Aldol reactions by Combination of Hydrogen-Bond Donating and Acyclic Amino Acid Catalysts2011In: Advanced Synthesis and Catalysis, ISSN 1615-4150, E-ISSN 1615-4169, Vol. 353, no 17, p. 3114-3122Article in journal (Refereed)
    Abstract [en]

    Highly enantioselective co-catalytic direct aldol reactions by a combination of simple hydrophobic acyclic amino acid and hydrogen-bond donating catalysts are presented. The corresponding aldol products are formed in high yields with high regio-, diastereo- (anti or syn) and enantioselectivity (up to 99.5:0.5 er). The catalyst loadings can be decreased to as little as 2 mol%.

  • 269.
    Ma, Guangning
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of applied science and design.
    Lin, Shuangzheng
    Stockholm Univ, Dept Organ Chem, Arrhenius Lab, S-10691 Stockholm, Sweden .
    Ibrahem, Ismail
    Mid Sweden University, Faculty of Science, Technology and Media, Department of applied science and design.
    Kubik, Grzegorz
    Stockholm Univ, Dept Organ Chem, Arrhenius Lab, S-10691 Stockholm, Sweden .
    Liu, Leifeng
    Stockholm Univ, Dept Mat & Environm Chem, Arrhenius Lab, S-10691 Stockholm, Sweden.
    Sun, Junliang
    Stockholm Univ, Dept Mat & Environm Chem, Arrhenius Lab, S-10691 Stockholm, Sweden.
    Cordova, Armando
    Mid Sweden University, Faculty of Science, Technology and Media, Department of applied science and design.
    Achiral Co-Catalyst Induced Switches in Catalytic Asymmetric Reactions on Racemic Mixtures (RRM): From Stereodivergent RRM to Stereoconvergent Deracemization by Combination of Hydrogen Bond Donating and Chiral Amine Catalysts2012In: Advanced Synthesis and Catalysis, ISSN 1615-4150, E-ISSN 1615-4169, Vol. 354, no 14-15, p. 2865-2872Article in journal (Refereed)
    Abstract [en]

    A stereochemical divergent approach for the highly enantioselective synthesis of distinct bicyclic products with multiple stereocenters from a racemate using a single chiral catalyst is disclosed. It is based on switches of the overall reaction pathways in the chiral amine-catalyzed cascade reactions between racemic ?-nitro ketones and a,beta-unsaturated aldehydes using different achiral co-catalysts. The utility of the method is exemplified by the highly diasteroselective switch and stereoconvergent deracemization process by combination of chiral amine and achiral hydrogen-bond-donating catalysts.

  • 270. MacDonald, J.C.
    et al.
    Jonsson, Anders
    Högskolan i Östersund.
    Ethyl nitrite: The in vivo synthesis of a mutagenic substance from tobacco smoke and ethanol1981In: Acta Chemica Scandinavica, ISSN 0904-213X, Vol. 335, p. 485-487Article in journal (Refereed)
  • 271. Marques, Eduardo F.
    et al.
    Edlund, Håkan
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    La Mesa, Camilo
    Khan, Ali
    Liquid Crystals and Phase Equilibria Binary Bile Salt-Water Systems2000In: Langmuir, ISSN 0743-7463, E-ISSN 1520-5827, Vol. 16, no 11, p. 5178-5186Article in journal (Refereed)
    Abstract [en]

    The phase behavior of several binary sodium bile salt-water systems is investigated over the entire concentration range, with emphasis on concentrated regions beyond the isotropic solution phase. The studied bile acid salts comprise the free salt sodium deoxycholate (SDC), the taurine conjugates sodium taurocholate (STC), sodium taurodeoxycholate (STDC), and sodium taurochenodeoxycholate (STCDC) and the glycine conjugate sodium glycodeoxycholate (SGDC). A combination of classical techniques is used, including phase diagram determination, polarizing microscopy, 2H NMR, and small-angle X-ray scattering (SAXS). The aggregation behavior in the isotropic micellar solutions of STC and STDC is also investigated by pulsed-field gradient NMR self-diffusion. The optical textures and the data from SAXS and 2H NMR clearly point to the formation of hexagonal liquid crystals, possibly of the reverse type, beyond the micellar solution for all the bile salts. Several unusual kinetic effects, such as very slow equilibration times and the formation of transient spherulitic crystals in biphasic regions, are observed. The phase diagrams and structural data are qualitatively discussed in terms of the molecular structure and solubility of the different salts. The formation of lyotropic liquid crystals by bile salts, which has remained unknown for decades, is clearly demonstrated in this work.

  • 272. Marques, Eduardo
    et al.
    Regev, Oren
    Edlund, Håkan
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Khan, Ali
    Micelles, Dispersions and Liquid Crystals in the Catanionic Mixture Bile Salt-Double-Chained Surfactant. The Bile Salt-Rich Area2000In: Langmuir, ISSN 0743-7463, Vol. 16, no 22, p. 8255-8262Article in journal (Refereed)
    Abstract [en]

    The phase behavior and phase structure for the catanionic pair sodium taurodeoxycholate - didodecyl-dimethylammonium bromide (DDAB) are investigated, at 25 degreesC. A combination of techniques is used including light and electron microscopy, small-angle X-ray scattering, and pulsed field gradient NMR self-diffusion. The bile salt micellar solution incorporates large amounts of the double-chained amphiphile, with the solution region extending to equimolarity. On the contrary, the hexagonal liquid-crystalline phase is destabilized by the addition of small amounts of DDAB. At equimolarity, coacervation instead of precipitation is observed, with formation of a viscous isotropic solution and a very dilute one. In the water-rich part of the phase diagram, a peculiar type of phase separation occurs, involving the formation of very fine bluish dispersions and a region of coexistence of two dispersions (double dispersion region). Microscopy and self-diffusion data for the solution region indicate limited growth of the mixed micelles. Large domains in which the micellar structure appears to be maintained are imaged in the bluish dispersions by electron microscopy. No other type of aggregate such as vesicles or precipitates is observed in the dilute bile salt-rich area of this mixture.

  • 273. Martini, A.
    et al.
    Baldassari, N.
    Baronio, P.
    Anderbrant, O.
    Hedenström, Erik
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Högberg, Hans-Erik
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Rocchetta, G.
    Mating disruption of the pine sawfly Neodiprion sertifer (Hymenoptera. Diprionidae) in isolated pine stands2002In: Agricultural and Forest Enthomology, ISSN 1461-9555, Vol. 4, no 3, p. 195-201Article in journal (Refereed)
    Abstract [en]

    1. Previous applications of the mating disruption technique to Neodiprion sertifer resulted in decreased numbers of males caught in the treated area but no effect on sex ratio or overall population density. 2. The present study assessed the efficacy of mating disruption against N. sertifer outbreaks in pine stands surrounded by agricultural areas or pasture, and therefore isolated from other infested areas. 3. Pine stands were treated by placing dispensers with an erythro-mixture of the acetate ester of 3,7-dimethyl-2-pentadecanol every 10 m in a grid. 4. The efficacy of this technique was evaluated by comparing the number of males caught in sticky traps baited with synthetic pheromone, and by comparing the sex ratio and the population density of the sawfly in the subsequent generation between treated and control pine stands. 5. The number of males caught within treated areas was significantly lower than in the control area. 6. In the treated pine stands 46% of the egg clusters resulted in male cocoons only, compared to 3% of the clusters in the control stand. 7. A significant reduction of the sawfly population was observed in the treated pine stands. The results contrast to the earlier mating disruption attempts with N. sertifer and can probably be ascribed to the isolation of the experimental stands.

  • 274. Moberg, M
    et al.
    Nilsson, E
    Holmström, Sara J. M.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Lundström, Ulla S
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Pettersson, J
    Markidies, K
    Fingerprinting siderophores by the exchange of iron by gallium and subsequent column- switched LC-ICP-MS.2003In: 16th IMSC (The International Mass Spectrometry Society);Edinburgh, Scotland, 2003-08-31 - 2003-09-05, 2003Conference paper (Other academic)
  • 275. Moberg, M.
    et al.
    Nilsson, E. M.
    Holmström, Sara
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Lundström, Ulla
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Pettersson, J.
    Markides, K.
    Fingerprinting metal-containing biomolecules after reductive displacement of iron by gallium and subsequent column-switched LC-ICP-MS analysis applied on siderophore.2004In: Analytical Chemistry, ISSN 0003-2700, E-ISSN 1520-6882, Vol. 76, no 9, p. 2618-2622Article in journal (Refereed)
    Abstract [en]

    Column-switching liquid chromatography followed by lowresolution ICPMS was evaluated as a tool for speciation analysis of metal-containing biomolecules. The strategy was applied on siderophores, strong iron chelators of low molecular weight (M-w < 1500). Prior to the LC-ICPMS analysis, reductive displacement of iron by gallium was performed using ascorbate as the reducing agent to increase the sensitivity. Different experimental conditions during the exchange reaction were tested using ferrichrysin and ferrichrome for evaluation. A reaction time of 30 min and a pH of 3.9 gave an exchange yield of 27 and 83% for ferrichrysin and ferrichrome, respectively. A gradient elution profile was also developed to separate gallium-chelated siderophores on a PGC column. Detection limits for standard solutions of ferrichrysin and ferrichrome in the low-nanomolar range were obtained by monitoring the gallium-69 isotope. The combined use of LC-ICPMS and LC-ESI-MS/MS was also evaluated as a tool to identify unknown metal complexes, here siderophores, in field soil solution samples.

  • 276.
    Moberg, My
    et al.
    Uppsala University.
    Bergquist, Jonas
    Uppsala University.
    Bylund, Dan
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    A generic stepwise optimization strategy for liquid chromatography electrospray ionization tandem mass spectrometry methods2006In: Journal of Mass Spectrometry, ISSN 1076-5174, E-ISSN 1096-9888, Vol. 41, no 10, p. 1334-1345Article in journal (Refereed)
    Abstract [en]

    The feasibility and advantages of using sophisticated chemometric tools in combination with the execution of thoroughly planned experiments to determine experimental conditions for optimal performance of an LC-ESI-MS/MS analysis is demonstrated. A stepwise strategy is proposed, which provides a controlled optimization procedure of the chromatographic quality (in terms of separation among the sample constituents) and maximizes the mass spectrometric signal of the selected product ions. Design of experiments (DOE) and response surface methodology are applied throughout the procedure. The stepwise approach has the advantage of dealing with the different optimization criteria separately, i.e. first ensuring sufficient chromatographic separation, then maximizing the amount of precursor ion entering the mass spectrometer, and finally generating high amounts of selected product ions. The experiments are performed on a linear ion trap mass spectrometer. Retention mapping using the band-tracking model is applied during LC development, which facilitates the optimization of segmented gradients. A set of different siderophores, strong iron chelates, is used as the model substances.

  • 277. Moberg, My
    et al.
    Bylund, Dan
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Danielsson, Rolf
    Markides, Karin E
    Optimization strategy for liquid chromatography-electrospray ionization mass spectrometry methods2000In: Analyst, ISSN 0003-2654, Vol. 125, p. 1970-1976Article in journal (Refereed)
    Abstract [en]

    A strategy for the optimization of liquid chromatography (LC)–electrospray ionization mass spectrometry methods is proposed. The optimization aims at good chromatographic quality and a high signal-to-noise ratio for the analyte. The three-step strategy comprises screening experiments, LC studies and infusion experiments, using empirical modelling to evaluate the experimental data. The optimization route was examined for three different cases: (a) estriol in a mixture of estrogens, (b) ibuprofen and related metabolites in urine and (c) morphine in the presence of codeine

  • 278. Moberg, My
    et al.
    Holmström, Sara
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Lundström, Ulla
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Markides, Karin
    Novel approach to the determination of structurally similar hydroxamate siderophores by column-switching capillary liquid chromatography coupled to mass spectrometry2003In: Journal of Chromatography A, ISSN 0021-9673, E-ISSN 1873-3778, Vol. 1020, no 1, p. 91-97Article in journal (Refereed)
    Abstract [en]

    In this study a new approach to determine three different siderophores (ferrichrome, ferrichrysin, ferricrocin) in natural soil solutions as well as in cultures of fungi is presented. The method includes enrichment of the analytes on a short pre-column, packed with C18 material, and subsequent highly selective separation of the analytes on a capillary porous graphitic carbon (PGC) column. In contrast to normal C18 packing materials, porous graphitic carbon offers chromatographic resolution between the three very similar analytes. The selectivity of the method is enhanced even further by the electrospray ionization (ESI) mass spectrometric detection. The combination of a short pre-column and a packed capillary separation column results in a method with high sensitivity. Reported detection limits, defined as the concentration giving the signal-to-noise ratio 3:1, is 27.7 pM for ferrichrome, 46.1 pM for ferricrocin and 37.4 pM for ferrichrysin.

  • 279. Moberg, My
    et al.
    Markides, Karin E
    Bylund, Dan
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Multi-parameter investigation of tandem mass spectrometry in a linear ion trap using response surface modelling2005In: Journal Of Mass Spectrometry, ISSN 1076-5174, Vol. 40, no 3, p. 317-324Article in journal (Refereed)
    Abstract [en]

    The feasibility of experimental design in combination with subsequent response surface modelling was illustrated for the prediction and interpretation of tandem mass spectrometric (MS/MS) fragmentation data using a linear quadrupole ion trap under various experimental conditions. The instrumental parameters included were (i) the pressure of the collision gas, (ii) the collision energy, (iii) the fill time of the linear ion trap and (iv) the scan rate. The spectral intensity and width of five fragment ions of the doubly charged neuro-active peptide bombesin were used for evaluation, and all experiments were performed so as to resemble the results obtained from a liquid chromatographic peak. The reported results show how fairly simple mathematical tools can be utilized successfully to describe fundamental mechanisms associated with multiple collisional activation and collision-induced dissociation processes without an extensively controlled experimental environment. Most beneficial, using the suggested approach, is the ability to study interaction (synergistic) effects between various parameters. As was realized from the results, many interaction effects are indeed significant. For example, the effect on the signal intensity of different collision gas pressure settings is strongly dependent on the settings of the other parameters. The described approach can easily be adopted for optimization purposes of any MS/MS experiment.

  • 280. Morozov, V. A.
    et al.
    Antzutkin, Oleg
    Koptyug, Andrey
    Institute of Chemical Kinetics and Combustion, Novosibirsk, USSR.
    Doktorov, A. B.
    Multiquantum resonances in low-field optically detected ESR of radical-ion pairs1991In: Molecular Physics, ISSN 0026-8976, E-ISSN 1362-3028, Vol. 73, no 3, p. 517-540Article in journal (Refereed)
    Abstract [en]

    Multiquantum resonances in low-field optically-detected electron spin resonance (ESR) spectra of radiation-induced radical-ion pairs of aromatic acceptors in liquid and some polymeric solutions have been studied experimentally and theoretically. Corresponding resonances occur in spectra under the action of relatively intense radiofrequency (RF) pumping, when usual signals are inverse due to spin-locking effect. Special experiments have been carried out to prove that such resonances are not caused by the apparatus. The dependencies of resonance shifts and intensities on the radiofrequency field amplitude for various polarizations of the RF field have been studied. The case of pumping with two independent RF generators has also been analysed. A general theory for multiquarium optically detected ESR spectra of radicalion pairs in liquid solutions has been developed, with spin relaxation processes being neglected. The theory has been applied to calculating multiquantum resonance parameters in transverse RF fields (H1 ⊥ H0) of various polarizations. The mechanism of multiquantum resonance spin dynamics of radical pairs (RP) has been analysed in detail. The shapes of OD ESR spectra components have been studied for the Poisson distribution of RP lifetimes. The developed theory shows qualitative agreement with experimental results

  • 281.
    Mridha, Moniruzzaman
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences. Uppsala University.
    Ma, Guangning
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Palo-Nieto, Carlos
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Afewerki, Samson
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences. Stockholm University.
    Cordova, Armando
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences. Stockholm University.
    Development of an Amino Acid/Hydroxy Oxime Dual Catalyst System for Highly Stereoselective Direct Asymmetric Aldol Reactions in the Presence of Water2017In: Synthesis (Stuttgart), ISSN 0039-7881, E-ISSN 1437-210X, Vol. 49, no 2, p. 383-390, article id ss-2015-z0592-opArticle in journal (Refereed)
    Abstract [en]

    An eco-friendly dual catalyst system for stereoselective aldol reactions in the presence of water is described. It is based on the cooperative action of acyclic amino acids and H-bond donating hydroxy oxime catalysts. The synthetic utility of this dual catalyst system was further demonstrated by applying it as the key step in the expeditious and highly stereoselective total synthesis of D-lyxo-phytosphingosine (29% overall yield). Here the amino acid/hydroxy oxime system significantly accelerated the direct aldol reactions in the presence of water as compared to organic solvents. The stereo-and chemoselectivity were also significantly increased.

  • 282.
    Musa, Najihah
    et al.
    IFM Biology, Conservation Ecology Group, Linköping University, Linköping, Sweden .
    Andersson, Klas
    Department of Plant Protection Biology, Swedish University of Agricultural Sciences, Alnarp, Sweden .
    Burman, Joseph
    Department of Plant Protection Biology, Swedish University of Agricultural Sciences, Alnarp, Sweden .
    Andersson, Fredrik
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Hedenström, Erik
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Jansson, Nicklas
    IFM Biology, Conservation Ecology Group, Linköping University, Linköping, Sweden .
    Paltto, Heidi
    IFM Biology, Conservation Ecology Group, Linköping University, Linköping, Sweden .
    Westerberg, Lars
    IFM Biology, Conservation Ecology Group, Linköping University, Linköping, Sweden .
    Winde, Inis
    Department of Plant Protection Biology, Swedish University of Agricultural Sciences, Alnarp, Sweden .
    Larsson, Mattias C.
    Department of Plant Protection Biology, Swedish University of Agricultural Sciences, Alnarp, Sweden .
    Bergman, Karl-Olof
    IFM Biology, Conservation Ecology Group, Linköping University, Linköping, Sweden .
    Milberg, Per
    IFM Biology, Conservation Ecology Group, Linköping University, Linköping, Sweden .
    Using Sex Pheromone and a Multi-Scale Approach to Predict the Distribution of a Rare Saproxylic Beetle2013In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 8, no 6, p. e66149-Article in journal (Refereed)
    Abstract [en]

    The European red click beetle, Elater ferrugineus L., is associated with wood mould in old hollow deciduous trees. As a result of severe habitat fragmentation caused by human disturbance, it is threatened throughout its distribution range. A new pheromone-based survey method, which is very efficient in detecting the species, was used in the present study to relate the occurrence of E. ferrugineus to the density of deciduous trees. The latter data were from a recently completed regional survey in SE Sweden recording >120,000 deciduous trees. The occurrence of E. ferrugineus increased with increasing amount of large hollow and large non-hollow trees in the surrounding landscape. Quercus robur (oak) was found to be the most important substrate for E. ferrugineus, whereas two groups of tree species (Carpinus betulus, Fagus sylvatica, Ulmus glabra, vs. Acer platanoides, Aesculus hippocastanum, Fraxinus excelsior, Tilia cordata) were less important but may be a complement to oak in sustaining populations of the beetle. The occurrence of E. ferrugineus was explained by the density of oaks at two different spatial scales, within the circle radii 327 m and 4658 m. In conclusion, priority should be given to oaks in conservation management of E. ferrugineus, and then to the deciduous trees in the genera listed above. Conservation planning at large spatial and temporal scales appears to be essential for long-term persistence of E. ferrugineus. We also show that occurrence models based on strategic sampling might result in pessimistic predictions. This study demonstrates how pheromone-based monitoring make insects excellent tools for sustained feedback to models for landscape conservation management.

  • 283.
    Månsson, P. E.
    et al.
    Swedish University of Agricultural Sciences, Alnarp.
    Schlyter, F.
    Swedish University of Agricultural Sciences, Alnarp.
    Eriksson, Carina
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Sjödin, Kristina
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Nonanoic acid, other alkanoic acids and related compounds as antifeedants in Hylobius abietis pine weevils2006In: Entomologia Experimentalis et Applicata, ISSN 0013-8703, E-ISSN 1570-7458, Vol. 121, no 3, p. 191-201Article in journal (Refereed)
    Abstract [en]

    A medium-length, straight-chain alkanoic acid, nonanoic acid, is known from laboratory microassays to be an antifeedant in adults of the large pine weevil, Hylobius abietis (L.) (Coleoptera: Curculionidae). Our hypothesis was that we could find new, less volatile alkanoic acids or related compounds suitable for field application and with improved long-term duration. Alkanoic acids of varying chain lengths (C6-C13) were tested for antifeedant activity in H. abietis adults. Microassay choice tests showed that straight-chain (C6-C11) alkanoic acids were active. However, high activities were restricted to the (C6-C10) acids, with the C9 (nonanoic acid) at 4 μmol cm-2 being the most active one. In a no-choice test on pine twigs, the antifeedant effect of C10 acid was lower than that of the C8 and C9 acids. In microassays, less volatile methyl-branched alkanoic acids exhibited lower antifeedant activities than did the corresponding straight-chain ones. However, the most active of the methyl-branched acids, 2-methyldecanoic acid, had an activity similar to that of nonanoic acid. Compounds related to nonanoic acid were either active (1-nonanol), weakly active (nonanoic anhydride), or inactive (nonanal, sodium nonanoate). The anhydride was highly active in the microassay, but less active on twigs. The antifeedant effects of the straight chain (C8-C10) alkanoic acids against pine weevil feeding were tested in the field. In contrast to the results from the twig tests, the less volatile C10 acid was more active in the field for the protection of transplants on fresh clear cuts over a 3-month period than both the C8 and C9 acids. Phytotoxic effects of the alkanoic acids were observed both in the field and in laboratory studies. If a protective layer of paraffin was applied to the stem prior to application of the alkanoic acids, these undesired side effects were reduced.

  • 284. Månsson, Per
    et al.
    Eriksson, Carina
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Sjödin, Kristina
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Antifeedants against Hylobius abietis pine weevils: An active compound in extract of bark of Tilia cordata linden2005In: Journal of Chemical Ecology, ISSN 0098-0331, Vol. 31, no 5, p. 989-1001Article in journal (Refereed)
    Abstract [en]

    Linden (Tilia cordata) bark contains antifeedants effective against the large pine weevil, Hylobius abietis. Soxhlet extraction of inner and outer bark resulted in an extract which showed antifeedant activity in a micro-feeding assay. The extract was fractionated by chromatography on silica gel using gradient elution with solvents of increasing polarity. The content of the fractions obtained was monitored by thin layer- and gas chromatography. Fractions of similar chemical composition were merged. Two of the 17 fractions showed antifeedant activity in the micro feeding assay. Nonanoic acid was identified in both of these fractions. Subsequent testing in the micro feeding assay showed that nonanoic acid possessed strong antifeedant activity against H. abietis adults.

  • 285.
    Nambu, Kei
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    van Hees, P. A. W.
    Essén, Sofia
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Lundström, Ulla
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Assessing centrifugation technique for obtaining soil solution with respect to leaching of low molecular mass organic acids from pine roots.2005In: Geoderma, ISSN 0016-7061, E-ISSN 1872-6259, Vol. 127, no 3-4, p. 263-269Article in journal (Refereed)
    Abstract [en]

    Centrifugation is a common technique to obtain soil solution. However, this method may disrupt living cells in the soil and release their contents into the soil solution. To examine this possibility, we compared leaching of low molecular mass organic acids (LMMOAs) and dissolved organic carbon (DOC) from the root of Scots pine (Pinus sylvestris) packed in quartz sand via extraction by centrifugation and milder procedures of water immersion and suction. Centrifugation enhanced leaching of shikimate appreciably; leaching of DOC, lactate, malate, and phosphate was also significantly enhanced. The concentration leached from the root was greater than 10 mu M for shikimate, and generally ranged between 0.5 and 5 mu M for the other acids. As for actual soil samples, this level of leaching could be appreciably large in upper mineral horizon(s) if the root density is as large as in our experiments and if the concentrations of LMMOAs in the soil matrix are relatively small.

  • 286.
    Nambu, Kei
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences, Engineering and Mathematics.
    van Hees, P A W
    Jones, D L
    Vinogradoff, S
    Lundström, Ulla S
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences, Engineering and Mathematics.
    Composition of organic solutes and respiration in soils derived from alkaline and non-alkaline parent materials2008In: Geoderma, ISSN 0016-7061, E-ISSN 1872-6259, Vol. 144, no 3-4, p. 468-477Article in journal (Refereed)
    Abstract [en]

    Parent material greatly influences pedogenesis and soil nutrient availability and consequently we hypothesized that it would significantly affect the amount of organic solutes in soil, many of which have been implicated in rhizosphere processes linked to plant nutrient uptake. Consequently, we investigated the influence of two contrasting parent materials in which calcite was present or absent (alkaline and non-alkaline soils) on the concentrations of dissolved organic carbon (DOC), low-molecular weight organic acids (LMWOA) and glucose in soil solution. Both soils were under Norway spruce. The dynamics of LMWOAs in soil were also investigated using 14C-labelled citrate and oxalate. Some of the mineral horizons of the alkaline soils showed significantly higher concentrations of DOC, phenolics, and fumarate in soil solution and also a higher basal respiration. No major differences were seen in organic solute status in the organic horizons of the two soil types. LMWOAs were present at low concentrations in soil solution (< 1 to 25 µM). Their mineralization rate significantly decreased with soil depth, however, overall neither their concentration or half-life in soil was markedly affected by parent material. The alkaline soils had significantly higher CO2-to-soil organic C (SOC) ratios, and consequently SOC in the alkaline soils did not seem more chemically stable against mineralization. Considering possible DOC and CO2 efflux rates it was suggested that the equal or larger SOC stocks in alkaline mineral soils were most likely linked to a higher net primary productivity. In conclusion, our study found that parent material exerted only a small effect on the concentration and dynamics of organic solutes in soil solution. This suggests that in comparison to other factors (e.g. vegetation cover, climate etc) parent material may not be a major regulator of the organic solute pool in soil.

  • 287.
    Nguyen, Ba-Vu
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Hedenström, Erik
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Candida rugosa lipase as an enantioselective catalyst in the esterification of methyl branched carboxylic acids: Resolution of rac-3,7-dimethyl-6-octenoic acid (citronellic acid)1999In: Tetrahedron: Asymmetry, ISSN 0957-4166, Vol. 10, no 9, p. 1821-1826Article in journal (Refereed)
  • 288.
    Nguyen, Ba-Vu
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Nordin, Ove
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Vörde, Carin
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Hedenström, Erik
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Högberg, Hans-Erik
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Structure vs. Enantioselectivity in Pseudomonas cepacia Lipase Catalysed Transesterifications: Enantioselective Acylation of Primary 2-Methylalcohols1997In: Tetrahedron: Asymmetry, ISSN 0957-4166, Vol. 8, no 7, p. 983-986Article in journal (Refereed)
  • 289.
    Nieberding, Caroline M
    et al.
    Evolutionary Biology Group, Institute of Biology, Leiden University, 2300 RA Leiden, Netherlands.
    Fischer, Klaus
    Zoological Institute and Museum, Greifswald University, Johann-Sebastian-Bach Str. 11/12, 17489 Greifswald, Germany.
    Saastamoinen, Marjo
    Metapopulation Research Group, Department of BioSciences, University of Helsinki, PO Box 65 (Viikinkaari 1), FI-00014, Finland.
    Allen, Cerisse E
    Division of Biological Sciences, University of Montana, Missoula MT 59812, United States.
    Wallin, Erika A.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of applied science and design.
    Hedenström, Erik
    Mid Sweden University, Faculty of Science, Technology and Media, Department of applied science and design.
    Brakefield, Paul M
    University Museum of Zoology Cambridge, Downing Street, Cambridge, CB2 3EJ, United Kingdom.
    Cracking the olfactory code of a butterfly: the scent of ageing.2012In: Ecology Letters, ISSN 1461-023X, E-ISSN 1461-0248, Vol. 15, no 5, p. 415-424Article in journal (Refereed)
    Abstract [en]

    Ecology Letters (2012) 15: 415-424 ABSTRACT: Although olfaction is a primary mode of communication, its importance in sexual selection remains understudied. Here, using the butterfly Bicyclus anynana, we address all the parameters of importance to sexual selection for a male olfactory signal. We show that variation in the male sex pheromone composition indicates male identity and male age. Courting males of different ages display small absolute (c. 200 ng) but large relative (100%) change of one specific pheromone component (hexadecanal) which, unlike the other components, showed no heritability. Females prefer to mate with mid-aged over younger males and the pheromone composition is sufficient to determine this preference. Surprisingly refined information is thus present in the male olfactory signal and is used for sexual selection. Our data also reveal that there may be no 'lek paradox' to resolve once the precise signal of importance to females is identified, as hexadecanal is, as expected, depleted in additive genetic variation.

  • 290.
    Niga, Petru
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Crown ethers at the aqueous solution–air interface: 1. Assignments and surface spectroscopy2011In: Physical Chemistry, Chemical Physics - PCCP, ISSN 1463-9076, E-ISSN 1463-9084, Vol. 13, no 17, p. 7930-7938Article in journal (Refereed)
    Abstract [en]

    The surface of aqueous solutions of 4-Nitro Benzo-15-Crown-5 (NB15C5) and Benzo-15-Crown-5 (B15C5) has been studied using the surface sensitive technique vibrational sum frequency spectroscopy (VSFS). The NO, CN, COC and CH vibrational modes of these compounds at the air–water interface as well as OH vibrational modes of the surface water hydrating this compound have been targeted in order to obtain molecular information about arrangement and conformation of the adsorbed crown ether molecules at the air–water interface. The CH2 vibrational modes of crown ethers have been identified and found to be split due to interaction with ether oxygen. The spectra provide evidence for the existence of a protonated crown complex moiety at the surface leading to the appearance of strongly ordered water species. The interfacial water species are influenced by the resulting charged interface and by the strong Zundel polarizability due to tunneling of the proton species between equivalent sites within the crown ring.

  • 291.
    Niga, Petru
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Crown ethers at the aqueous solution–air interface. Part 2. Electrolyte effects, ethylene oxide hydration and temperature behaviour2011In: Physical Chemistry, Chemical Physics - PCCP, ISSN 1463-9076, E-ISSN 1463-9084, Vol. 13, no 17, p. 7939-7947Article in journal (Refereed)
    Abstract [en]

    Vibrational Sum Frequency Spectroscopy (VSFS) was employed to study adsorbing films of 4-Nitro Benzo-15-Crown-5 (NB15C5) and Benzo-15-Crown-5 (B15C5) at the aqueous solution–air interface. The surface of the solution is strongly influenced by the presence of crown ether species. Changes in the orientation of NB15C5 were monitored as a function of solution concentration, by targeting the ratio of peak intensities of the CN and NO2 vibrational modes. The water of hydration has also been probed as a function of crown concentration, salt concentration, and temperature. The latter study strongly suggests that the surface can be treated as a charged interface, and that the associated ordered water decreases with increasing ionic strength of the bulk solution.

  • 292.
    Nilsson, Anna
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences, Engineering and Mathematics.
    Identification and Syntheses of Semiochemicals Affecting Mnesampela privata and Trioza apicalis2009Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    The Autumn gum moth, Mnesampela privata (Lepidoptera: Geometridae) is an endemic Australian moth whose larvae feed upon species of Eucalyptus. The moths favorite host plants are E. globulus and E. nitens which are the most important species used in commercial plantations of the Australian pulpwood industry. The autumn gum moth has become one of the most significant outbreak insects of eucalyptus plantations throughout Australia. As a consequence great financial losses to the forest industry occur. Today insecticides such as pyrethroids are used for control of eucalyptus defoliators as M. privata.

    The carrot psyllid, Trioza apicalis (Homoptera: Psylloidea), is one of the major pests of carrot (Daucus carota) in northern Europe. The psyllid causes curling of the carrot leafs and reduction of plant growth. Today the carrot crops are protected with the pyrethroid insecticide cypermethrin, which is toxic to aquatic organisms and is, from 2010, prohibited for use in Sweden by the Swedish Chemicals Inspectorate.

    An alternative to insecticides is to protect the seedlings with semiochemicals, a chemical substance or mixture of them that carries a message. This thesis describes the identification and the syntheses of semiochemicals from the above mentioned insect species.

    From analysis of abdominal tip extracts of M. privata females from Tasmania a blend of (3Z,6Z,9Z)-3,6,9-nonadecatriene and (3Z,6Z,9Z)-3,6,9-heneicosatriene was identified as the sex pheromone of this species. The identification of the C19- and C21-trienes was confirmed by synthesis.

    In the analysis of carrot leaf extracts we found a compound, α-cis-bergamotene, that induces antennal response in the carrot psyllid. This is just the beginning of the studies of trying to manipulate this psyllid with semiochemicals instead of insecticides.

  • 293.
    Nilsson, Per
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Jansson, M
    Brydsten, L
    Retention and long term accumulation of EOC1 from pulp mill effluents in a Baltic Sea recipient2003In: Water, Air and Soil Pollution, ISSN 0049-6979, E-ISSN 1573-2932, Vol. 143, no 1-4, p. 225-243Article in journal (Refereed)
    Abstract [en]

    The total inventory and distribution of Extractable Organic Chlorine (EOCl) has been investigated in an estuary exposed to pulp mill effluents for over 50 yr. The estuarine turnover of suspended particulate matter (SPM) and associated pollutants was studied using a model describing important processes for EOCl accumulation. The recipient has a low retention of SPM due to dominating stratified conditions in the water column. The total inventory of EOCl in the sediment is therefore relatively low as compared with the total discharge. It was found that the vertical distribution of EOCl has a close relationship to the extent of chlorine use at the mill. Discharges of SPM from the pulp production process play a major role in establishing the chronology of the sediment. A modernisation of the mill from 1986 to 1991 considerably reduced the discharges of chlorinated substances. In the near future there will be an accumulation of EOCl in the estuary.

  • 294. Nilsson, S. L.
    et al.
    Andersson, C
    Sjöberg, Per J. R
    Bylund, Dan
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Petersson, Patrik
    Jörntén-Karlsson, Magnus
    Markides, Karin E
    Phosphate buffers in capillary electrophoresis/mass spectrometry using atmospheric pressure photo ionization and electrospray ionization2003In: Rapid Communication in mass spectrometry, ISSN 0951-4198, Vol. 17, no 20, p. 2267-2272Article in journal (Refereed)
    Abstract [en]

    Capillary electrophoresis (CE) has been combined with atmospheric pressure photoionization (APPI) and electrospray ionization (ESI) for mass spectrometric (MS) detection. Separation conditions using potassium phosphate buffer and ammonium formate buffer have been compared for analysis of eleven pharmaceutical bases. The results showed improvements in separation efficiency and peak symmetry when phosphate buffer was used. The low flow in CE may enable utilization of these advances with MS detection. Compared with ESI, the APPI technique provided a cluster-free background. The enhanced signal-to-noise ratio in the total ion current (TIC) and the reduced spectral background indicated that the APPI process is less affected by non-volatile salts in the CE buffers. This results in a wider range of choice of CE buffers in CE/MS analysis when APPI is the ionization method.

  • 295. Nilsson, Sara L
    et al.
    Bylund, Dan
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Jörntén-Karlsson, Magnus
    Petersson, Patrik
    Markides, Karin E
    A chemometric study of active parameters and their interaction effects in a nebulized sheath-liquid electrospray interface for capillary electrophoresis-mass spectrometry2004In: Electrophoresis, ISSN 0173-0835, E-ISSN 1522-2683, Vol. 25, no 13, p. 2100-2107Article in journal (Refereed)
    Abstract [en]

    A chemometrics approach has been used for evaluating the effect of four experimental parameters when coupling capillary electrophoresis (CE) to electrospray ionization-mass spectrometry (ESI-MS). Electrospray voltage, sheath-liquid flow rate, nebulizing gas flow rate, and spray needle position in respect to the MS orifice were varied according to a full factorial design. In addition to main effects, two interaction effects could be identified as significant when measuring the peak intensity of the analytes, from a sample mixture containing peptides and pharmaceuticals. The first interaction effects, between the nebulizing gas flow rate and the sheath-liquid flow rate, and the second interaction effect, between the nebulizing gas flow rate and the spray position, could further explain the impact that these variables have on the spray performance. The number of theoretical plates and the baseline noise were also measured. The sheath-liquid flow was found to significantly affect the separation efficiency, while the noise level mainly was controlled by the nebulizing gas flow. The same factorial design was also used for a CE capillary with lower internal diameter (ID) and the effects of the same variables were compared on those capillaries using equal injection volume for both capillaries. Similar trends were obtained in both capillaries but capillary ID was shown to be a significant variable when evaluating both capillaries in a single model. It was found that a capillary with 25 m ID provided improved CE-MS performance over than corresponding 50 m ID capillary. Enhanced sensitivity was obtained using the narrow-bore capillary, and at lower sheath-liquid flow rate the 25 m ID capillary also gave rise to more efficient peaks.

  • 296.
    Nordin, Ove
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Hedenström, Erik
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Högberg, Hans-Erik
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Stereochemistry of 1,6-Germacradien-5-ol, a Constituent of the Needles of Scots Pine Pinus silvestris) and the Defence Secretation from Larvae of the Pine Sawfly Neodiprion sertifer1999In: Acta Chemica Scandinavica, ISSN 0904-213X, Vol. 53, no 2, p. 124-132Article in journal (Refereed)
  • 297.
    Nordin, Ove
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Nguyen, Ba-Vu
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Vörde, Carin
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Hedenström, Erik
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Högberg, Hans-Erik
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Kinetic Resolution of Primary 2-methylalcohols via Pseudomonas cepacia Lipase Catalysed Enantioselective Acylation2000In: Journal of The Chemical Society. Perkin Transactions 1, ISSN 1472-7781, p. 367-376Article in journal (Refereed)
    Abstract [en]

    The enantioselectivities of lipases from Pseudomonas cepacia (PFL, Amano PS, etc.) towards a series of primary 2-methyl-substituted alcohols using vinyl acetate as the acyl donor in transesterifications in organic solvents were studied. In terms of enantioselectivity, the best results were found for 3-aryl-2-methylpropan-1-ols with enantiomeric ratios (E-values) over 100 in most cases, whereas other 3-substituted primary 2-methylpropan-1-ols generally displayed lower enantioselectivities: 3-cycloalkyl-2-methylpropan-1-ols (E ≈ 20) and 2-methylalkan-1-ols (E ≈ 10). Moving the aryl group closer or further away from the chiral centre resulted in low enantioselectivities: 2-arylpropan-1-ols (E < 10), 2-methyl-4-(2-thienyl)butan-l-ol (E = 12), 2-methyl-5-(2-thienyl)pentan-l-ol (E=3.2) and 2-methyl-6-(2-thienyl)hexan-l-ol (E=3.8).

  • 298.
    Norgren, Magnus
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    NMR self-diffusion measurements as analytical tool - possibilities and restrictions2007In: Pulp and paper chemical analysis seminar, 4th 2007: modern analytical techniques for the future mill : abstracts, Stockholm: STFI-Packforsk , 2007Conference paper (Other scientific)
    Abstract [en]

    Pulsed field gradient (PFG) NMR self-diffusion has been proved as an excellent method to extract structural information from different solutions. Therefore, this technique has been a versatile tool among physical chemists in studies of surfactant self-assembly for some decades. Besides that the method is non-destructive, some of the benefits are that external disturbance of the analysed system is cancelled and the possibilities of studying several molecular species simultaneously. Moreover, in contrast to �common� solution NMR, deuterated solvents are not necessary to perform the studies. NMR self-diffusion measurements can also be applied in the field of polymers to extract molecular mass distributions and polydispersity data. The focus of this talk is to introduce and discuss the possibilities and limitations of the PFG NMR self-diffusion technique as an analytical tool in the pulp and paper area.

  • 299.
    Norgren, Magnus
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    On the Physical Chemistry of Kraft Lignin: Fundamentals and Applications2001Doctoral thesis, monograph (Other scientific)
  • 300.
    Norgren, Magnus
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Some aspects on the physical chemistry of kraft lignins in aqueous solutions: Theoretical considerations and practical implications.2000Licentiate thesis, monograph (Other scientific)
3456789 251 - 300 of 436
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf