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  • 701. Winka, Katarina
    et al.
    Eriksson, Ove E
    Bång, Åsa
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Molecular evidence for recognizing the Chaetothyriales 1998Inngår i: Mycologia, ISSN 0027-5514, Vol. 90, nr 5, s. 822-830Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The 18S rRNA gene sequences from the bitunicate ascomycetes Ceramothyrium linnaeae (Chaetothyriaceae) and Coccodinium bartschii (Coccodiniaceae) were determined and aligned with the corresponding sequences from 33 other ascomycetes and one basidiomycete, Boletus satanas. Phylogenetic analyses of these sequences supported previous reports that the Herpotrichiellaceae (Capronia, black yeasts, etc.) are distant from Dothideales and Pleosporales. A new sequence of Ceramothyrium linnaeae, representing the family Chaetothyriaceae, is monophyletic with representatives of the Herpotrichiellaceae, suggesting that both families can be accommodated in the order Chaetothyriales. The concept of Chaetothyriales can not be based on the presence of periphysoids, since Coccodinium bartschii, which also has periphysoids, clustered with members of the Dothideaceae. The Chaetothyriales are not closely related to other bitunicates, but are the sister group of either Eurotiales or Lecanorales/Peltigerales.

  • 702. Wängberg, Sten-Åke
    et al.
    Selmer, Johanne-Sophie
    Gustavsson, Kim
    Ekelund, Nils
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    UV-B Effects on Nordic Marine Ecosystem – A literature Review1997Bok (Annet vitenskapelig)
  • 703.
    Wågberg, Lars
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Polyelectrolyte adsorption on cellulose fibres: a review2001Rapport (Annet vitenskapelig)
  • 704.
    Wågberg, Lars
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Polyelectrolyte adsorption onto cellulose fibres - A review2000Inngår i: Nordic Pulp & Paper Research Journal, ISSN 0283-2631, E-ISSN 2000-0669, Vol. 15, nr 5, s. 586-597Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This review focuses upon the following questions: a) Why are the polyelectrolytes adsorbed onto cellulosic fibres? The easiest way to describe the adsorption is as an interaction between the charges on the fibres and the charges on the polyelectrolytes. However the entropy gain upon the release of counterions to the charges on the fibres and the polyelectrolytes gives a much larger contribution to the adsorption energy than the charge interaction. There are some investigations which clarify the influence of certain basic parameters on the fibres and the surfaces and these investigations will be reviewed. An attempt will also be made to create a link between published adsorption data and the Scheutjens-Fleer theory for polyelectrolyte adsorption. Another important question is how the polyelectrolytes are adsorbed on the fibres, i.e. are the segments only found in trains on the surface or will there be some loops and/or tails protruding into the solution? Very little is known about this but the topic will be discussed in some detail. b) Where are the polyelectrolytes adsorbed - on the external surfaces of the fibres or within the fibre wall and how is this related to the molecular properties of the polyelectrolytes? There are a lot of definitions in the literature about fibre surfaces, external surfaces etc. but it is important to link the adsorption to molecular properties and the work in this area will be reviewed. The influence of fines will also be discussed. c) What controls the kinetics of polyelectrolyte adsorption and are there models to describe this adsorption? It is still not entirely known how polymers that adsorb onto the internal surfaces of the fibres are then transported through the fibre wall. The work conducted in this area will be reviewed, It is also important to know the kinetics of the reconformation of the polymer on the fibre surface and this topic will also be discussed in detail. Finally the kinetics of desorption will be treated.

  • 705.
    Wågberg, Lars
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Spreading of droplets of different liquids on specially structured papers2000Rapport (Annet vitenskapelig)
  • 706. Wågberg, Lars
    et al.
    Forsberg, Sven
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Johansson, A
    Juntti, P
    Engineering of fibre surface properties by application of the polyelectrolyte multilayer concept: Part I: Modification of paper strength2002Inngår i: Journal of Pulp and Paper Science (JPPS), ISSN 0826-6220, Vol. 28, nr 7, s. 222-228Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Consecutive layers of cationic polyallylamine and anionic polyacrylic acid have been deposited on both unbeaten and beaten fully bleached cellulosic fibres. By preparing sheets of these fibres and by forming 5-10 layers of these polyelectrolytes on the unbeaten fibres, it was possible to develop the same strength as can be achieved by conventional beating. Experiments show that considerable strength improvement can be achieved with this type of treatment also on beaten fibres. Atomic force microscopy investigations of multilayers of the polylectrolytes formed on silicon oxide surfaces showed that the thickness of 10 layers of polyelectrolytes was 52 nm. Since the strength improvement was significant with 5 layers, it is suggested that a 26 nm thick multilayer of polyelectrolytes is sufficient to create a strong joint between fibres. The structure of the polyelectrolyte multilayers formed on the fibres was not determined.

  • 707.
    Wågberg, Lars
    et al.
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Hägglund, R
    SCA Packaging Research.
    Kinetics of polyelectrolyte adsorption on cellulosic fibers2001Inngår i: Langmuir, ISSN 0743-7463, E-ISSN 1520-5827, Vol. 17, nr 4, s. 1096-1103Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The present investigation has been focused on studying the adsorption of three different molecular mass fractions of a polydimethyldiallylammonium chloride (DMDAAC) (8750 (LMw), 48 000 (MMw), and 1 200 000 (HMw)) on bleached chemical fibers. Both kinetics of adsorption and equilibrium adsorption measurements have been conducted, and the adsorption has been measured by polyelectrolyte titration. The results show that the LMw polymer can reach all the charges in the fiber wall whereas the MMw and HMw can only reach the charges on the external surfaces of the fibers. It is also shown that the kinetics of adsorption of the LMw polymer is not at all affected by the presence of a saturated layer of HMw polymer on the surface of the fibers. Finally the results from the investigation show that it is possible to have a full coverage of the external surface of the fibers by a high molecular mass polymer and a full coverage of the internal surface of the fibers with a low molecular mass polymer provided that the high molecular mass polymer is adsorbed before addition of the low molecular mass polymer. This is true if the polymers are adsorbed to the same type of groups on the fibers. A simplistic model for describing ployelectrolyte adsorption in turbulent flow also shows good agreement with measured values for the low molecular mass polyelectrolyte whereas the agreement for the high molecular polyelectrolyte is not as good. For the high molecular mass polyelectrolyte a more sophisticated model is needed.

  • 708.
    Wågberg, Lars
    et al.
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Hägglund, Rickard
    SCA packaging Research.
    Kinetics of polyelectrolyte adsorption on cellulosic fibres2000Rapport (Annet vitenskapelig)
  • 709. Wågberg, Lars
    et al.
    Pettersson, Gunilla
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Notley, Shannon
    Adsorption of bilayers and multilayers of cationic and anionic copolymers of acrylamide on silcon oxide2004Inngår i: Journal of Colloid and Interface Science, ISSN 0021-9797, E-ISSN 1095-7103, Vol. 274, nr 2, s. 480-488Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Silica surfaces were consecutively treated with copolymers of cationic and anionic polyacrylamides (C-PAM and A-PAM, respectively) and the layer-by-layer build-up was continuously monitored with the aid of stagnation point adsorption reflectometry (SPAR). Four different charge densities of the cationic polymer and one charge density of the anionic polymer were studied. The solid substrate used in the investigation was an oxidized Si wafer, the charge of which was varied by performing the measurements at different pH. Adsorption measurements were performed both in deionized water and with a background electrolyte concentration of 0.01 M NaCl The results show that the adsorption of C-PAM at pH 6 was dominated by electrostatic interactions. However, a significant nonionic contribution to the adsorption of C-PAM on SiO2 was detected-when the results of adsorption measurements conducted in deionized water and in 0.01 M NaCl were compared. At pH 9, the adsorption of C-PAM onto SiO2 was found to be geometrically restricted since the adsorption stoichiometry between the polymer charges and the charges on the surface was less than I irrespective of the charge of the C-PAM. Adsorption of the A-PAM onto the C-PAM covered surface increases as a function of the adsorbed charges in the first layer. Experiments showed that it was possible to form multilayers of polyelectrolytes on the SiO2 surface provided the charge of the C-PAM was high enough. The critical charge of the polyelectrolyte for the formation of multilayers was also dependent on the charge of the substrate; that is, the lower the surface charge the higher the critical charge of the C-PAM. The substrate affected the amount of polyelectrolyte adsorbed up to the fifth layer. For further layers there was almost a stoichiometric relationship between the charges of the polyelectrolytes in consecutive layers. Results from studies of the formed multilayers with a quartz crystal microbalance (QCM-D) indicated that there was a close correlation between energy dissipation into the multilayers and a decrease in the adsorption as detected with SPAR. This in turn indicates that a decrease in the reflectometer signal does not necessarily indicate a decrease in adsorption.

  • 710.
    Wågberg, Lars
    et al.
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Westerlind, Christina
    SCA.
    Spreading of droplets of different liquids on specially structured papers2000Inngår i: Nordic Pulp & Paper Research Journal, ISSN 0283-2631, E-ISSN 2000-0669, Vol. 15, nr 5, s. 598-606Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The spreading kinetics of drops of different liquids (water, glycerol and ethylene glycol) on different types of model papers have been investigated. In the first part of the investigation single ply and two-ply papers, made from pulps with different degrees of beating, were investigated. The results show that is very common the surface layer of the paper had a much larger influence on the spreading than the bottom ply. By normalising the data showing the drop radius as a function of time with the viscosity and surface tension of the liquids all data collapse onto a master curve. The results from the first part of the investigation also show that in order to determine a contact angle between the liquid and the paper the drop volume should remain constant and the contact angle should be determined when the drop has reached its equilibrium volume. In the second part of the investigation the influence of surface topography and surface energy of the papers on the spreading kinetics was determined. The results show that when the pattern of use, the avails on the surface creates fine capillaries the contact angle is decreased compared to the situation with a flat surface. For papers with a higher roughness the uneven structure creates barriers against the spreading which increases the contact angle compared to the situation with a flat surface. A simple attempt to fit the data to a power law based on a hydrodynamic approach was also conducted. The results from this treatment show that it is possible to get a good match for the sheets with virtually only surface spreading. The constants achieved in this treatment can be used to rationalise the spreading data to be compared with other investigations.

  • 711. Xiong, Shaojun
    et al.
    Johansson, Mats
    Hughes, Francine
    Hayes, Adrian
    Richards, Keith
    Nilsson, Christer
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Interactive effects of soil moisture, vegetation canopy, plant litter and seed addition on plant diversity in a wetland community2003Inngår i: Journal of Ecology, ISSN 0022-0477, E-ISSN 1365-2745, Vol. 91, nr 6, s. 976-986Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    1 We carried out a factorial experiment to examine how groundwater availability (low and high sites with intermediate or rare flooding), vegetation canopy, leaf litter and seed availability interacted to determine the species richness of a productive wet grassland community in Wicken Fen National Nature Reserve, Cambridgeshire, UK. Seeds of 18 species were added to half the plots in each of eight combinations of elevation, canopy and litter, and seedling emergence was observed for two growing seasons.2 Both individual and interactive effects on plant diversity and colonization were determined for all four examined factors. Interactive effects explained 41-63% of the total variation in both species richness and numbers of individuals growing from added seeds.3 Neither elevation nor vegetation canopy had significant individual effects on total species richness, but their interaction was significant. Litter addition limited seedling emergence at the low elevation but favoured it at the high elevation.4 The relative importance of vegetation canopy and plant litter in affecting plant community composition varied with the community parameter considered (species richness or number of seedlings), elevation and stage of vegetation development. In general, plant litter was more important in determining species richness, whereas the vegetation canopy was more important in determining seed germination and seedling emergence. Plant litter was also more important than vegetation canopy at an early stage of vegetation development and at low elevation.5 Seed availability was the most important factor in determining overall species richness in the studied community. The influence of the local seed bank was very limited. Seedling emergence and seedling species richness were generally enhanced by lower elevation and seed addition, but depressed by vegetation and litter addition.6 The complex relationships observed have considerable implications for ecological modelling and ecosystem restoration. Manipulation of one factor may produce unexpected effects on other factors, which may induce a series of consequences for the whole community. Further knowledge on how natural communities are organized and maintained is needed to guide the management of ecosystems.

  • 712.
    Xiong, Shaojun
    et al.
    Umea Univ, Landscape Ecol Grp, Dept Ecol & Environm Sci, SE-90187 Umea.
    Nilsson, Christer
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Johansson, Mats E
    Umea Univ, Landscape Ecol Grp, Dept Ecol & Environm Sci, SE-90187 Umea.
    Jansson, Roland
    Umea Univ, Landscape Ecol Grp, Dept Ecol & Environm Sci, SE-90187 Umea.
    Responses of riparian plants to accumulation of silt and plant litter: the importance of plant traits2001Inngår i: Journal of Vegetation Science, ISSN 1100-9233, E-ISSN 1654-1103, Vol. 12, s. 481-490Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A 2-yr field experiment was used to determine the response of riparian plants to accumulation of litter or silt in a river flood-plain meadow in northern Sweden. Such disturbances occur regularly in free-flowing rivers but are likely to change as a result of global changes in land use or climate. We anticipated that plants with different traits would differ in their response to litter and silt accumulation. We quantified plant response as relative change in above-ground biomass, and regressed it on either litter mass or silt depth, and on plant traits such as lateral spread, plant height, relative growth rate, seed mass and seed persistence in soil. The relative changes in riparian plant biomass following litter or silt accumulation were negatively related to litter mass and silt depth, and positively related to most examined plant traits Such as seed mass. seed persistence and lateral spread. The vegetation recovery in the second season was largely determined by plant traits; litter or silt accumulation had no significant effect. Litter accumulation selected for large-seeded species, but silt accumulation selected for species with strong ability of lateral spread. Seed persistence was a useful variable in predicting species recovery from both litter and silt accumulation. Plant height was negatively related to plant recovery, but relative growth rate was not significantly related to relative change in plant biomass after silt or litter accumulation. Our results imply that plant traits are important variables to consider for predicting the responses of riparian vegetation to deposition of organic and inorganic matter.

  • 713.
    Zhang, Jin
    et al.
    McMaster Ctr. for Pulp/Paper Res., Department of Chemical Engineering, McMaster University, Hamilton, Ont. L8S 4L7, Canada.
    Pelton, Robert
    McMaster Ctr. for Pulp/Paper Res., Department of Chemical Engineering, McMaster University, Hamilton, Ont. L8S 4L7, Canada.
    Wågberg, Lars
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Rundlöf, M.
    SCA Research AB, SE-850 03 Sundsvall.
    The effect of molecular weight on the performance of paper strength-enhancing polymers2001Inngår i: Journal of Pulp and Paper Science (JPPS), ISSN 0826-6220, Vol. 27, nr 5, s. 145-151Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The influence of dextran molecular weight (77 000 to 2 000 000) on the strength of fibre-fibre bonds was investigated. A series of cationic dextrans with different molecular weights, from 77 000 to 2 000 000, was prepared and the adsorption behaviour on fibre was characterized. The maximum amount of adsorbed dextran increased with decreasing molecular weight, while the adsorbed layer thickness on colloidal silica increased with increasing molecular weight. At saturation coverage, the molecular weight of dextran did nor affect the tensile strength of handsheets made from unbeaten bleached kraft pulp. The strength improvement with polymer addition did not correspond to increased optical bonded area (opacity). The external surface of fibre accessible to dextran of molecular weight 2 000 000 was estimated as 35 m(2)/g.

  • 714. Zhang, Jin
    et al.
    Pelton, Robert
    Wågberg, Lars
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Rundlöf, Mats
    The effect of charge density and hydrophobic modification on dextran-based paper strength enhancing polymers2000Inngår i: Nordic Pulp & Paper Research Journal, ISSN 0283-2631, E-ISSN 2000-0669, Vol. 15, nr 5, s. 440-445Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The dry tensile strengths of bleached kraft pulp handsheets were measured as functions of the cationic charge density and hydrophobic substituents on 2 million Dalton dextran adsorbed onto the fibers before sheet making. The charge density controlled the maximum amount of dextran that could be adsorbed by the fibers which, in turn, influenced tensile strength. The lower the charge density, the higher were both the dextran adsorption capacity of fibers and the tensile strength of the resulting paper. Butanoic and hexanoic acid when condensed onto dextran gave hydrophobic domains which lowered paper strength linearly with hydrophobic content. An extension to the Page equation gave a semi-empirical model which predicted the major effects of hydrophobic substitution on paper strength.

  • 715. Zhang, Zhen
    et al.
    Wang, Hongbin
    Chen, Guofa
    Anderbrant, Olle
    Zhang, Yun
    Zhou, Shuzhi
    Hedenström, Erik
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Högberg, Hans-Erik
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Sex pheromone for monitoring flight periods and population densities of the pine sawfly, Diprion jingyuanensis2005Inngår i: Journal of Applied Entomology, ISSN 0931-2048, Vol. 129, nr 7, s. 368-374Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Sex pheromone for monitoring flight periods and population densities of the pine sawfly, Diprion jingyuanensis

  • 716.
    Zimmerman, J K M
    et al.
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Palo, Thomas R
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    The decline and extinction of Noble crayfish in the river Ljungan, Mid-Sweden.: A case of non-sustainable harvest2007Inngår i: 92nd ESA/SER Joint Meeting, San Jose 5-10 August 2007, 2007Konferansepaper (Fagfellevurdert)
  • 717.
    Öberg, Lisa
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Trädgränsdynamik på Sånfjället2002Inngår i: Svensk Botanisk Tidskrift, ISSN 0039-646X, Vol. 96, nr 3/4, s. 177-185Artikkel i tidsskrift (Annet vitenskapelig)
  • 718.
    Öberg, Lisa
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Trädgränsprojektet - lägesrapport 20062007Rapport (Annet vitenskapelig)
  • 719.
    Öberg, Lisa
    et al.
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Kullman, L.
    Fjällvärld i förvandling - klimatförändringens effekter på fjällens växtliv2006Inngår i: Jämten, Östersund: Jamtli förlag , 2006, s. 83-91Kapittel i bok, del av antologi (Annet vitenskapelig)
  • 720.
    Östberg, Tomas
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Effects of organic amendments on the biodegradation of petroleum hydrocarbons in contaminated soil2006Doktoravhandling, med artikler (Annet vitenskapelig)
  • 721.
    Östberg, Tomas
    et al.
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för teknik, fysik och matematik.
    Jonsson, Anders
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Bylund, Dan
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Lundström, Ulla
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    The effects of carbon sources and micronutrients in fermented whey on the biodegradation of n-hexadecane in diesel fuel contaminated soil2007Inngår i: International Biodeterioration & Biodegradation, ISSN 0964-8305, E-ISSN 1879-0208, Vol. 60, nr 4, s. 334-341Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The effect of organic amendments on the biodegradation of n-alkanes and phenanthrene in diesel contaminated soil was evaluated. The organic amendments used were fermented and non fermented sweet milk whey and the mineralization was estimated by analysis of evolved 14CO from added 14C-hexadecane, 14C-octadecane and 14C-phenanthrene. The addition of 2100 mg dry weight (dw) sweet whey kg-1 soil dw at the start of the experiment increased the extent of mineralization after 184 days compared to a control, from 45 % to 61 % for n-hexadecane and from 35 % to 46 % for n-octadecane. The stimulation was characterized according to a three-half-order kinetic such as if a greater part of the substrates was mineralized according to first order kinetics. Similar stimulation was achieved from the fermented whey when 210 mg dw kg-1 soil dw was added to the soil every second week during the 184 days of incubation.

  • 722.
    Östberg, Tomas
    et al.
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Jonsson, Anders
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för teknik, fysik och matematik.
    Lundström, Ulla
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för informationsteknologi och medier.
    Enhanced biodegradation of diesel fuel hydrocarbons in soil by the addition of fermented whey2005Konferansepaper (Annet vitenskapelig)
    Abstract [en]

    Industrial organic byproducts such as whey or fermented whey contain easily accessible carbon and micronutrients which could be used to stimulate microbial degradation of hazardous organic contaminants in soil. In this work we have investigated the possibility to use fermented whey as a growth supplement to enhance the aerobic degradation of diesel fuel hydrocarbons in soil. Experiments were carried out with two soils, a sand soil and a loamy sand soil, contaminated with diesel fuel at a concentration of 5000 mg kg-1 soil dry weight (dw). Fermented whey was added at different dosages to nutrient amended soil microcosms. Petroleum hydrocarbon mineralization was monitored by analysis of evolved 14CO2 from added 14C-labeled n-hexadecane. Mineralization curves were fitted to a three-half-order kinetics model. Enhanced mineralization was observed in sand soil at 7 and 22C and in loamy sand soil at 22C but the stimulatory effect was most pronounced in the sand soil at 22C, where the addition of 6 and 60 ml fermented whey kg-1 soil dw, increased the final degree of n-hexadecane mineralization from 49% in the control soil to 60 and 67% respectively. The increased total mineralization was characterized by an increase in the amount of substrate mineralized by first-order kinetics despite a decrease in the first order rate constant, k1. The highest concentration of fermented whey, 60 ml kg-1, gave rise to substrate competition, diauxie, which resulted in an extended lag phase.

  • 723.
    Östberg, Tomas
    et al.
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för teknik, fysik och matematik.
    Jonsson, Anders
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Lundström, Ulla
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Enhanced degradation of n-hexadecane in diesel fuel contaminated soil by the addition of fermented whey2007Inngår i: Soil & sediment contamination: an international journal, ISSN 1532-0383, Vol. 16, nr 2, s. 221-232Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The objective of this work has been to investigate the possibility of using fermented whey as an organic growth supplement in order to enhance the aerobic degradation of n-hexadecane in soil. Fermented whey was added at different dosages to nutrient amended soil microcosms contaminated with 5000 mg diesel fuel kg-1 dry weight (dw). The target substance was 14C-labeled n-hexadecane, and the biodegradation was monitored by analysis of evolved 14CO2. Biodegradation curves were fitted to a three-half-order kinetics model. Enhanced biodegradation was observed in sand at 7 and 22C and in loamy sand at 22C but the effect was most pronounced in the sand soil at 22C. The addition of 6 or 60 ml fermented whey kg-1 soil dw, increased the degree of n-hexadecane biodegradation at the end of the experiment, 167 days, from 49% in the untreated sand to 60 or 67% respectively. This increase in biodegradation was characterized by an increase in the amount of substrate biodegradation by first-order kinetics despite a decrease in the first order rate constant, k1. The highest concentration of fermented whey, 60 ml kg-1, gave rise to substrate competition, diauxie, which resulted in an extended lag phase.

  • 724.
    Östberg, Tomas L
    et al.
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Jonsson, A P
    Lundström, Ulla
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Bylund, Dan
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Effects of whey addition on the biodegradation of n-hexadecane, n-octadecane and phenanthrene in diesel fuel contaminated soilManuskript (Annet vitenskapelig)
  • 725.
    Östberg, Tomas L.
    et al.
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för teknik, fysik och matematik.
    Jonsson, Anders P
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för teknik, fysik och matematik.
    Lundström, Ulla S.
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Accelerated biodegradation of n-alkanes in aqueous solution by the addition of fermented whey2006Inngår i: International Biodeterioration & Biodegradation, ISSN 0964-8305, E-ISSN 1879-0208, Vol. 57, nr 3, s. 190-194Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The effect of fermented whey on the aerobic degradation of n-alkanes by a microbial consortium was investigated in an aqueous system. Microbial degradation of 100 mg n-alkanes (C12, C14, C16 and C18) in mineral nutrient medium was assessed by measuring the decrease in n-alkanes, production of CO2 and increase in biomass. The addition of fermented whey at a concentration of 5 mg dry weight to a nutrient medium receiving a small-sized inoculum (103.4 CFU ml-1)shortened the lag phase from 8 to 3 days, but the degradation rate during the degradation phase was not enhanced. The shortened lag phase at low initial concentration of microorganisms indicates that the fermented whey stimulates growth in the initial phase, without reducing the consortium's capacity for n-alkane degradation.

  • 726. Östrand, Fredrik
    et al.
    Anderbrant, Olle
    Wassgren, Ann-Britt
    Bergström, Gunnar
    Hedenström, Erik
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Högberg, Hans-Erik
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Nguyen, Ba-Vu
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Larsson, Michael
    Stereoisomeric composition of the sex pheromone of the pine sawfly Microdiprion pallipes (Hym., Diprionidae)2003Inngår i: Chemoecology, ISSN 0937-7409, E-ISSN 1423-0445, Vol. 13, nr 3, s. 155-162Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The basic chemical structure of the sex pheromone of the pine sawfly Microdiprion pallipes (Fallen) has earlier been identified as the propionate ester of (2S,3S,7 R/S,11 R/S)/(2R,3R,7 R/S,11 R/S)-3,7,11-trimethyl-2-tridecanol. We now report the results from further investigations on the male response to individual stereoisomers and to blends of stereoisomers, both in electroantennographic (EAG) recordings and in field trapping experiments. We also present our attempts to determine the stereochemistry of the compounds present in females of M. pallipes. By comparing gas chromatograms and mass spectra obtained from natural extracts with those from synthetic compounds it was found that the females contain one or more of the four (2S,3S,7 R/S,11 R/S)-3,7,11-trimethyl-2-tridecanol isomers (SS++-1). The active pheromone component is the corresponding propionate ester 2. In EAG experiments, males responded most strongly to five propionate ester samples, namely two four-isomer blends: SS++-2 and SR++-2, and three individual stereoisomers: SSSR-, SRRR- and SRSR-2. In a series of field trapping experiments it was found that males were attracted to the SR++-2 four-isomer blend and to the individual isomer SSSR-2. Based on the EAG-recordings and field responses of males and the stereoisomers found in the females, we suggest that the propionate ester of (2S,3S,7S,11R)-3,7,11-trimethyl-2-tridecanol (SSSR-2) is used as a main component of the sex pheromone in M. pallipes. Apparently the males react to other stereoisomers in addition to that or those produced by the females.

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