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  • 301.
    Högberg, Hans-Erik
    et al.
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Larsson, Michael
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Pherodip: Third coordination meeting, Freising, Munchen, Germany, deltagande.1997Konferensbidrag (Övrigt vetenskapligt)
  • 302.
    Högberg, Hans-Erik
    et al.
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Lindmark, Marica
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Isaksson, Dan
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Sjödin, Kristina
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Franssen, M
    Jongejan, H
    Wijnberg, J
    de Groot, A
    Formation of hemiacetal esters in lipase-catalysed reactions of vinyl esters with hindered secondary alcohols2000Ingår i: Tetrahedron Letters, ISSN 0040-4039, E-ISSN 1359-8562, Vol. 41, nr 17, s. 3193-3196Artikel i tidskrift (Refereegranskat)
  • 303.
    Höglund, Hans
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Mechanical Pulping2009Ingår i: Pulping Chemistry and Technology / [ed] Ek, M., Gellerstedt, G., Henriksson, G., Stockholm: KTH Royal Institute of Technology, 2009, s. 57-90Kapitel i bok, del av antologi (Övrigt vetenskapligt)
  • 304. Ilvesniemi, H.
    et al.
    Giesler, R.
    van Hees, Patrick
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Magnussson, T.
    Melkerud, P. A.
    General description of the sampling techniques and the sites investigated in the Fennoscandinavian podzolization project2000Ingår i: Geoderma, ISSN 0016-7061, E-ISSN 1872-6259, Vol. 94, nr 2-4, s. 109-123Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A 3-year project focusing on the fundamental processes of podzolization was carried out on three sampling sites in northern Fennoscandinavia. The soils were selected based on the previous information of the soil properties to represent typical soils in the area. In this article, the post-glacial history of the sites, site vegetation and general properties of the soils, as well as the methods used are presented. Two of the sites were classified as Typic HapLocryods and one as an Entic Haplocryod. The post-glacial age of the sites was between 9000 and 9500 years BP and the parent material was glacial till in one of the sites and glaciofluvial material in two of them. (C) 2000 Elsevier Science B.V. All rights reserved.

  • 305. Isaac, Giorgis
    et al.
    Bylund, Dan
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Månsson, Jan Eric
    Markides, Karin E
    Bergquist, Jonas
    Analysis of phosphatidylcholine and sphingomyelin molecular species from brain extracts using capillary liquid chromatography electrospray ionization mass spectrometry2003Ingår i: Journal of Neuroscience Methods, ISSN 0165-0270, Vol. 128, nr 1/2, s. 111-119Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    One feature of complex lipids is that many subtypes of these molecules exist as a diverse mixture in a biological sample. Qualitative and quantitative analysis of these closely related molecules require sensitive and specific analytical methods to detect intact phospholipids (PL) and sphingomyelin (SM) species and to differentiate between them. Conventional analytical methods require laborious procedures including separation by column, argentation thin-layer chromatography or liquid chromatography (LC) after pre- or post-column derivatization. In the present work, a method based on reversed phase capillary LC coupled on-line to electrospray ionization mass spectrometry (LC/ESI/MS) has been developed to gather tools for lipidomic studies, i.e. the profiling of complex mixtures of lipids in small amounts of various cells and tissues. The LC/MS system used consisted of an LC pump in an isocratic elution, a reversed phase capillary column and a single quadrupole mass spectrometer operated in the positive ion mode. A successful separation of phosphatidylcholine (PC) and SM molecular species was obtained with a minimum detectable quantity (MDQ) in the low fmol range injected on column. The method was applied to human brain extracts. Furthermore, the extraction efficiencies of the traditional Folch method and pressurized fluid extraction (PFE) were compared using the human brain. It was found that the intensity of the PC and SM molecular species extracted by PFE is two times that of Folch.

  • 306.
    Isaksson, Dan
    et al.
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Högberg, Hans-Erik
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Sjödin, Kristina
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Enantioselektiv syntes av norterpenen Cryptone: 19:e Organikerdagarna, 14-17 juni, Linköping2004Konferensbidrag (Övrigt vetenskapligt)
  • 307.
    Isaksson, Dan
    et al.
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Högberg, Hans-Erik
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Sjödin, Kristina
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Enantioselektiv syntes av seskviterpenen torreyol och andra kadinenderivat: 20:e Organikerdagarna, 12-15 juni 2006, Kalmar, Poster2006Konferensbidrag (Övrigt vetenskapligt)
  • 308.
    Isaksson, Dan
    et al.
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Lindmark Henriksson, Marica
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Sjödin, Kristina
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Högberg, Hans-Erik
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Hemiacetal ester formation in lipase catalysed transesterifications of vinyl esters with hindered secondary alcohols: Meeting abstract2003Ingår i: ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY, 2003Konferensbidrag (Refereegranskat)
  • 309.
    Isaksson, Dan
    et al.
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Lindmark-Henriksson, Marica
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Sjödin, Kristina
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Högberg, Hans-Erik
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Hemiacetals and their esters as side-products in lipase catalysed transesterification of vinyl esters with sterically hindered alcohols2004Ingår i: Journal of Molecular Catalysis B: Enzymatic, ISSN 1381-1177, E-ISSN 1873-3158, Vol. 31, nr 1-3, s. 31-37Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Hemiacetals and their esters are formed as side-products in lipase catalysed transesterification of vinyl esters with sterically hindered secondary alcohols. Scope and limitations of the reaction as well as the consequences of it for lipase catalysed kinetic resolutions are discussed.

  • 310.
    Isaksson, Dan
    et al.
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Sjödin, Kristina
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Högberg, Hans-Erik
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Enantiomerically enriched cryptone by lipase catalysed kinetic resolution2006Ingår i: Tetrahedron: asymmetry, ISSN 0957-4166, E-ISSN 1362-511X, Vol. 17, nr 2, s. 275-280Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Thiophenol was added to racemic cryptone (4-isopropyl-2-cyclohexene-1-one) and the resulting 1,4-addition products, cis- and trans-4-isopropyl-3-(phenylsulfanyl)cyclohexanone) were separated and the latter reduced to rac-1,3-cis-1,4-trans-4-isopropyl-3-(phenylsulfanyl)cyclo¬he¬xanol which was subjected to lipase catalysed resolution by acylation catalysed by CAL-B (Candida antarctica lipase B). The remaining alcohol was separated from the produced acetate, which was hydrolysed to the alcohol. The enantiomeric alcohols so obtained were oxidised. The initial products, probably sulfoxidoketones spontaneously decomposed to furnish enantiomerically enriched (R)- and (S)-cryptone with up to 76% and 98% ee, respectively.

  • 311.
    Isaksson, Per
    et al.
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Gradin, Per
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Östlund, Sören
    Solid Mechanics, KTH.
    A simplified treatise of the Scott bond testing method2007Ingår i: Proceedings of the 2007 International Paper Physics Conference, May 6-11, 2007, Gold Coast, Qld, Australia, 1-6, 2007, 2007Konferensbidrag (Övrigt vetenskapligt)
    Abstract [en]

    The Scott bond test method has been used extensively in the paper industry over the years as a mean to assess the bond strength of paper. The method has been a subject of some controversy lately since it does not always correlate to the sensitivity of the material to fracture by delamination.

     

    To gain some further insight into which parameters govern the fracture process in a Scott bond test a simplified approach has been chosen in order to formulate an analytical mathematical/mechanical model of the test. The model is dynamic in the sense that inertia effects are included. The material model utilised is a simple cohesive theory that assumes a linear behaviour between stress and crack opening when the material has started to degrade. This choice of material model makes the mathematical model very nonlinear. In fact, a system of three coupled nonlinear second order partial differential equations have to be solved and adjusted to the correct initial conditions.

     

    The material parameters needed for the model are the elastic modulus in the thickness direction, the transverse shear (elastic) modulus, the tensile strength (in the thickness direction) and the fracture work (per unit area) for a delamination crack.

     

    To investigate the ability of the model, a Scott bond testing apparatus have been equipped with a piezoelectric load sensor. The load cell was mounted on the apparatus' pendulum so that the load acting on the sample holder could be recorded during the whole impact stage. This was done for a number of different initial velocities of the pendulum and it is found that the model gives a fair prediction of the contact load.

  • 312.
    Isaksson, Per
    et al.
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Hägglund, R.
    A mechanical model of damage and delamination in corrugated board during folding2005Ingår i: Engineering Fracture Mechanics, ISSN 0013-7944, E-ISSN 1873-7315, Vol. 72, nr 15, s. 2299-2315Artikel i tidskrift (Refereegranskat)
  • 313. Ivarsson, P
    et al.
    Tittiger, C
    Blomquist, C
    Borgeson, C
    Seybold, S
    Blomquist, G
    Högberg, Hans-Erik
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Pheromone precursor synthesis is localized in the metathorax of Ips paraconfusus Lanier (Coleoptera : Scolytidae)1998Ingår i: Naturwissenschaften, ISSN 0028-1042, Vol. 85, nr 10, s. 507-511Artikel i tidskrift (Refereegranskat)
  • 314. Jansson, R.
    et al.
    Nilsson, Christer
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Dynesius, M.
    Andersson, E.
    Effects of river regulation on river-margin vegetation: A comparison of eight boreal rivers2000Ingår i: Ecological Applications, ISSN 1051-0761, E-ISSN 1939-5582, Vol. 10, nr 1, s. 203-224Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Regulation and fragmentation by dams belong to the most widespread deliberate impacts of humans on the world's rivers, especially in the Northern Hemisphere. We evaluated the effects of hydroelectric development by comparing the flora of vascular plants in 200-m-long reaches of river margin distributed along eight entire rivers in northern Sweden. Four of these rivers were free-flowing, and four were strongly regulated for hydroelectric purposes. First, we compared species diversity per site between entire free-flowing and regulated rivers. To reduce the effects of natural, between-river variation, we compared adjacent rivers. One regulated river had lower plant species richness and cover than two adjacent free-flowing ones, whereas two other parallel rivers, one regulated and another free-flowing, did not differ significantly. Second, river-margin vegetation responded differently to different types of regulated water-level regimes. Both along run-of-river impoundments, with small but daily water-level fluctuations, and along storage reservoirs, with large fluctuations between low water levels in spring and high levels in late summer and fall, the number of species and their cover per site were lower than along the free-flowing rivers. Regulated but unimpounded reaches were most similar to free-flowing rivers, having lower plant cover per site, but similar numbers of species. For reaches with reduced discharge, evidence was mixed; some variables were lower compared to free-flowing rivers whereas others were not. However, for the last two types of regulation, statistical power was low due to small sample sizes. Third, we classified all plant species according to their dispersal mechanisms and tested whether they respond differently to different types of regulated water-level regimes. Three out of four types of regulation had higher proportions of wind-dispersed species, and two out of four had lower proportions of species without specific mechanisms for dispersal, compared to free-flowing rivers, suggesting that dispersal ability is critical for persistence following regulation. Run-of-river impoundments had higher proportions of long-floating species and species with mechanisms for vegetative dispersal, suggesting that water dispersal may still be important despite fragmentation by dams. Fourth, plant species richness and cover varied with both local factors, such as water-level regime, and regional factors, such as length of the growing season. Presence of clay and silt in the river-margin soil, preregulation position of the contemporary river margin, non-reservoir sites, low altitudes, and long growing seasons were associated with high plant species richness and cover.

  • 315.
    Jansson, R.
    et al.
    Umeå University.
    Nilsson, Christer
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap. Umeå University.
    Renöfält, Birgitta
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap. Umeå University.
    Fragmentation of riparian floras in rivers with multiple dams2000Ingår i: Ecology, ISSN 0012-9658, E-ISSN 1939-9170, Vol. 81, nr 4, s. 899-903Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Rivers are increasingly fragmented by dams, resulting in disruption of natural dispersal pathways and subsequent changes of riverine communities. We assessed the effect of dams as barriers to plant dispersal along rivers by comparing the flora of vascular plants between pairs of run-of-river impoundments in northern Sweden. Adjacent impoundments in similar environmental settings develop different riparian floras because species with poor floating capacity become unevenly distributed among impoundments. Such discontinuities were not found along a free-flowing river, suggesting effective dispersal of riparian plants in the absence of dams. Given that dams regulate most of the world's rivers, floristic disruptions of riparian corridors may be a global phenomenon. The extensive fragmentation of other ecosystems may have caused similar obstructions to organism dispersal, with subsequent changes in species composition.

  • 316. Johansson, Björn
    et al.
    Anderbrant, Olle
    Simandl, Jiri
    Avtzis, Nikolaos
    Salvadori, Christina
    Hedenström, Erik
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Edlund, Helen
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Högberg, Hans-Erik
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Release Rates for Pine Sawfly Pheromones from Two Types of Dispensers and Phenology of Neodiprion sertifer2001Ingår i: Journal of Chemical Ecology, ISSN 0098-0331, E-ISSN 1573-1561, Vol. 27, nr 4, s. 733-745Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Comparisons of release rates, duration in the field, and catch efficiency of polyethylene and cotton roll dispensers for the sex pheromones of sawflies (Hymenoptera: Diprionidae) were conducted. The release rates of the Neodiprion sertifer (Geoffr.) and Diprion pini (L.) sex pheromones, the acetates of pentadecanol and (2S,3S,7S)-3,7-dimethyl (2S,3R,7R)-3,7-dimethyl-2-tridecanol from polyethylene dispensers were measured at different temperatures in the laboratory. The release rates for the substances depended on both the temperature and initial load in the vials. The catch from cotton rolls baited with 100 μg of the acetate or propionate of 3,7-dimethyl-2-pentadecanol was compared to the catch from regularly renewed cotton rolls baited with 10 μg of the same acetate. The catch was higher for the 100-μg cotton rolls for, at most, 45 days, and there was no significant difference in catch between the acetate and the propionate. The catch in traps baited with polyethylene or cotton roll dispensers loaded with the acetate of 3,7-dimethyl-2-pentadecanol was compared and showed that cotton roll traps mirrored the decreasing release of the substance rather than the actual flight activity. The length of the flight period of N. sertifer in Sweden, the Czech Republic, Italy, and Greece did not exceed 100 days in any of the countries. By adjusting the initial pheromone load of the polyethylene vials to the expected temperatures, it should be possible to get a constant and sufficiently high release rate during the entire flight period.

  • 317. Johansson, E
    et al.
    Lingström, R
    Norgren, Magnus
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Wågberg, L
    Evaluation of Adhesion between Polyelectrolyte Multilayers using AFM. : Poster - Veeco Scandinavian User Meeting2007Konferensbidrag (Övrigt vetenskapligt)
  • 318. Johansson, M. E.
    et al.
    Nilsson, Christer
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Responses of riparian plants to flooding in free-flowing and regulated boreal rivers: an experimental study2002Ingår i: Journal of Applied Ecology, ISSN 0021-8901, E-ISSN 1365-2664, Vol. 39, nr 6, s. 971-986Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    1 The long history of river regulation has resulted in extensively changed ecosystem structures and processes in rivers and their associated environments. This fact, together with changing climatic and hydrological conditions, has increased the need to recover the natural functions of rivers. To develop guidelines for river restoration, comparative ecological experiments at contrasting water-level regimes are needed. We compared growth and survival of transplanted individuals of four riparian plant species (Betula pubescens, Carex acuta, Filipendula ulmaria and Leontodon autumnalis) over 2 years on four free-flowing and four regulated riverbank sites in northern Sweden. The species were chosen as representatives of dominating life-forms and species traits on different elevations of the riverbanks.

    • 2 In Betula and Filipendula, mean proportional growth rates were significantly higher at free-flowing sites than at regulated sites, whereas no consistent differences between free-flowing and regulated sites were found in Carex and Leontodon. Differences among species were generally in accordance with natural distribution patterns along riverbank elevation gradients and with experimental evidence on flooding tolerance, although plants of all species survived and even showed positive growth rates on elevations below their natural range of occurrence.
    • 3 Partial least squares regression was used to relate plant performance (growth and survival) to duration, frequency and timing of flooding at the different sites. Flood duration and frequency typically reduced performance in all species and during all time periods, although to various degrees. Flood events early in the experiment determined the outcome to a high degree at all sites. Variables indicating a regulated regime were mostly negatively related to plant performance, whereas free-flowing regime variables were positively related to plant performance.
    • 4 We used two of the regression models generated from our data with an acceptably high predictive power to simulate a hypothetical re-regulation scenario in run-of-river impoundments. With an overall reduction in flooding duration and frequency of 50–75%, plant performance of Filipendula at low riverbank elevations showed predicted increases of about 20–30%, levelling off to zero at the highest elevations. Reductions in summer floods represented about one-third to half of this increase.
    • 5 We conclude that for a range of species individual plant performance is clearly reduced on banks of impoundments and storage reservoirs due to changes in the water-level regime. Furthermore, our model simulation suggests that rather substantial reductions of flood duration and frequency are needed to improve plant performance on riverbanks upstream from dams in impounded rivers. River restoration principles should, however, be based on a combination of experimental data on plant performance of individual species and observed long-term changes in plant communities of regulated rivers. Consequently, successful re-regulation schemes in boreal rivers should include both reductions of summer and winter floods as well as re-introduced spring floods.
  • 319. Johansson, Therese
    et al.
    Olsson, Jörgen
    Hjältén, Joakim
    Jonsson, Bengt Gunnar
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Ericson, Lars
    Beetle attraction to sporocarps and mycelia of wood-decaying fungi in old-growth spruce forests of northern Sweden2006Ingår i: Forest Ecology and Management, ISSN 0378-1127, E-ISSN 1872-7042, Vol. 237, s. 335-341Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Many saproxylic beetles do not feed on wood directly but on fungi colonizing the wood. The volume of decaying wood has decreased drastically in Scandinavian managed forest landscapes in recent years, so improved knowledge on the interactions between beetles and wood-decaying fungi is important for the long-term persistence of these trophic partners. Sporocarps of polypores are known to emit volatiles attracting both fungivorous and predatory beetles, but it is unknown whether some beetles are also attracted to odours from the mycelia. The aim of this experiment was to test the attraction of beetles to volatiles from the sporocarps and mycelia of wood-decaying fungi. In a randomized block design, six substrate types: Fomitopsis pinicola sporocarp, F. pinicola mycelium-infected wood, Fomitopsis rosea sporocarp, F. rosea mycelium-infected wood, Phellinus chrysoloma sporocarp and Phlebia centrifuga mycelium-infected wood were attached separately to specially designed window traps in four old-growth spruce forests in northern Sweden. Empty traps and traps with sterilised wood were used as controls. We found no significant differences in the species richness or abundance of saproxylic beetles between the control and sterilised wood and the fungal substrates. However, two abundant species showed significant preferences for one substrate type. The bark beetle Dryocoetes autographus preferred F. rosea mycelium-infected wood and the rove beetle Lordithon lunulatus preferred fruiting bodies of F. pinicola. The results indicate that some species do discriminate between volatiles emitted by different polypore species and also between volatiles emitted by the sporocarps and mycelia from the same species. Our data indicate a hitherto unknown interdependence between D. autographus and F. rosea. We conclude that present knowledge on interactions between beetles and wood-decaying fungi is limited and further studies are needed to enhance our ability to design appropriate conservation strategies in the forest landscape.

  • 320. Jones, D L
    et al.
    Dennis, P G
    Owen, A G
    van Hees, P A W
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Organic acid behavior in soils - misconceptions and knowledge gaps2003Ingår i: Plant and Soil, ISSN 0032-079X, E-ISSN 1573-5036, Vol. 248, nr 1-2, s. 31-41Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Organic acids have been hypothesized to perform many functions in soil including root nutrient acquisition, mineral weathering, microbial chemotaxis and metal detoxification. However, their role in most of these processes remains unproven due to a lack of fundamental understanding about the reactions of organic acids in soil. This review highlights some of the knowledge gaps and misconceptions associated with the behavior of organic acids in soil with particular reference to low-molecular-weight organic acids (e.g., citrate, oxalate, malate) and plant nutrient acquisition. One major concern is that current methods for quantifying organic acids in soil may vastly underestimate soil solution concentrations and do not reveal the large spatial heterogeneity that may exist in their concentration (e.g., around roots or microbes). Another concern relates to the interaction of organic acids with the soil's solid phase and the lack of understanding about the relative importance of processes such as adsorption versus precipitation, and sorption versus desorption. Another major knowledge gap concerns the utilization of organic acids by the soil microbial community and the forms of organic acids that they are capable of degrading (e.g., metal-complexed organic acids, adsorbed organic acids etc). Without this knowledge it will be impossible to obtain accurate mathematical models of organic acid dynamics in soil and to understand their role and importance in ecosystem processes. Fundamental research on organic acids and their interaction with soil still needs to be done to fully elucidate their role in soil processes.

  • 321.
    Jonsson, Bengt-Gunnar
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    A null-model for randomization tests of nestedness in species assemblages2001Ingår i: Oecologica, ISSN 0029-8549, Vol. 127, nr 3, s. 309-313Artikel i tidskrift (Refereegranskat)
  • 322.
    Jonsson, Bengt-Gunnar
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Availability of Coarse Woody Debris in a Boreal Old-Growth Picea abies Forest2000Ingår i: Journal of Vegetation Science: official organ of the international association for vegetation science, ISSN 1100-9233, Vol. 11, nr 1, s. 51-56Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This study reports temporal (based on cross-dated dead trees) and spatial patterns of availability of coarse woody debris (CWD) from Picea abies in a Swedish boreal landscape with discrete old-growth forest patches in a wetland matrix. Data were collected from 29 patches ranging in size from 0.3 to 28 ha. A total of 897 dead trees with a minimum diameter of 15 cm occurred on the 7.2 ha area analysed. The year of death was established for 50 % of these trees. CWD volume ranged from 17 to 65 msup3/sup/ha for downed logs and from 0.5 to 13 cmsup3/sup/ha for standing snags. CWD of all decay stages and diameter classes occurred abundantly and the probability of finding logs of all decay stages and sizes was very high at the scale of single hectares. Tree mortality differed among 5 yr periods. However, during the last 50 yr no 5 yr period produced less than 3 logs/ha. Decay rates were highly variable among different logs. Logs with soft wood and some wood pieces lost (decay stage 5) died ca. 34 years ago. This suggests a fairly rapid decay in this northern forest. The data indicate a high and continuous availability of CWD of all types. It is likely, therefore, that selection pressures for efficient dispersal among CWD dependent species may not be very high. Consequently, species with narrow habitat demands and/or low dispersal ability may have evolved and this may contribute to the decrease of certain species in the managed landscape.

  • 323.
    Jonsson, Bengt-Gunnar
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Biologisk mångfald i skogen - Många bra åtgärder men räcker det?2002Ingår i: Miljöforskning - Formas tidning - för ett uthålligt samhälle, ISSN 1650-4925, s. 19-21Artikel i tidskrift (Övrigt vetenskapligt)
  • 324.
    Jonsson, Bengt-Gunnar
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Hur används landskapet?: Att bevara biologisk mångfald i det brukade skogslandskapet2003Ingår i: Kungliga Skogs- och Lantbruksakademiens Tidskrift, ISSN 0023-5350, Vol. 142, nr 1, s. 91-94Artikel i tidskrift (Övrigt vetenskapligt)
  • 325.
    Jonsson, Bengt-Gunnar
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Rollspel i gränslandet naturvetenskap och samhälle - Exemplet "Gurken". 1999Ingår i: Lära - lärande - lärare: universitetspedagogisk konferens i Umeå 18-19 februari 1999 : konferensrapport, Umeå: Univ. , 1999Konferensbidrag (Övrigt vetenskapligt)
  • 326.
    Jonsson, Bengt-Gunnar
    et al.
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Jonsell, Mats
    Exploring potential biodiversity indicators in boreal forests1999Ingår i: Biodiversity and Conservation, ISSN 0960-3115, Vol. 8, nr 10, s. 1417-1433Artikel i tidskrift (Refereegranskat)
  • 327.
    Jonsson, Bengt-Gunnar
    et al.
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Kruys, N.
    Ranius, T.
    Ecology of species living on dead wood - Lessons for dead wood management2005Ingår i: Silva Fennica, ISSN 0037-5330, E-ISSN 2242-4075, Vol. 39, nr 2, s. 289-309Artikel, forskningsöversikt (Refereegranskat)
    Abstract [en]

    Dead wood has been identified as a crucial component for forest biodiversity. Recent research has improved our understanding of habitat relations for many species associated with dead wood. However, the consequences for forest management are yet to be explored. In this review we build upon the growing volume of studies on dead wood dependent species, the dynamics of dead wood and ecological theory in order to identify the challenges for forest management at the landscape level. The review has a Fennoscandian focus, but the problems and challenges are similar in many forest ecosystems. We argue that it is necessary to 1) counteract the current shortage in availability of dead wood, 2) concentrate planning at the landscape level in order to minimize isolation and reduce edge effects, 3) create a variety of dead wood types, and 4) utilise available quantitative analytical tools. This calls for new approaches to management that to a large extent includes available knowledge, and to find platforms for planning forested landscapes with diverse holdings.

  • 328.
    Jonsson, Bengt-Gunnar
    et al.
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Kruys, Nicholas
    Ecology of woody debris in boreal forest2001Samlingsverk (redaktörskap) (Övrigt vetenskapligt)
    Abstract [en]

    Today dead trees are not only viewed upon as waste and as potential sources of pest species. Instead they have gained an increased attention as key factors for biodiversity in many ecosystems. This change in focus and concern has sparked intense research activities directed to explore the ecological role of dead trees in forest ecosystems. Focus is directed into three main areas: 1) to understand thepatterns of woody debris availability in relation to forest stand dynamics and effects of forestry, 2) the role of woody debris in nutrient and particularly carbon dynamics in forest ecosystems, and 3) the pattern and biology of the utilization of woody debris for a large number of wood-dependent species. This volume summarises the present knowledge and presents a set of case studies on the role of dead wood in boreal forests. The focus is on Fennoscandian boreal forests.However, the results presented have a wide applicability and thus the volume may serve as a general introduction to the importance of woody debris in forest ecosystems.

  • 329.
    Jonsson, Bengt-Gunnar
    et al.
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Laaka-Lindberg, S.
    Lammi Biological Station, Finland.
    State of Bryophyte Ecology 2005: the final meeting of the BRYOPLANET network held in Kéked, Hungary 19-25 August 20052006Ingår i: Lindbergia, ISSN 0105-0761, E-ISSN 2001-5909, Vol. 31, nr 1-2, s. 3-5Artikel i tidskrift (Övrigt vetenskapligt)
    Abstract [en]

    BRYOPLANET, a bryophyte population and landscape analysis network, was funded by the Nordic Research Board (Nordforsk) from 2001-2005 to arrange scientific meetings, workshops and courses for researchers and students on bryophyte ecology in the Nordic and Baltic countries. It provided a tool for connecting bryologists in the region and elsewhere. The network succeeded in connecting experienced reserachers’ broad knowledge with young enthusiastic post-graduate students with fresh ideas. In the final meeting of the network in Kéked, Hungary on 19-22 August 2005 and during the post-meeting excursion on 22-25 August, 2005, the present state of research was discussed with strong emphasis on identifying the highlights and also the weaknesses in the many fields of bryophyte ecology today. The meeting consisted of seven invited retrospective lectures, offered by specialists in different fields of bryophyte ecology, and reserachers and students had an opportunity to present ongoing projects to the audience. In addition to the lectures, the meeting consisted of 15 presentations ranging from phylogeographic patterns to morphological adaptations, population dynamics and genetics. Retrospective lectures have been published, along with some of the original papers presented at the Kéked meeting. This introduction presents and evaluates the history, aims and outcomes of the BRYOPLANET network in addition to reporting on the final meeting in Kéked.

  • 330.
    Jönsson, Karin
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    A dendrohydrological method for reconstruction of river flow in the Swedish boreal zone: Tree Rings and People - An International Conference on the Future of Dendrochronology2001Konferensbidrag (Övrigt vetenskapligt)
  • 331.
    Jönsson, Karin
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Possibilities to reconstruct long-term changes in flood disturbances in the boreal riparian zone.2003Ingår i: The Ecology and Management of Wood in World Rivers, Bethesda, Maryland: American Fisheries Society , 2003Konferensbidrag (Övrigt vetenskapligt)
  • 332.
    Jönsson, Karin
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Reconstruction of riverflow in the Swedish boreal zone2001Ingår i: Detecting environmental change: science and society, 17-20 july 2001, London, UK, 2001Konferensbidrag (Övrigt vetenskapligt)
  • 333.
    Jönsson, Mari
    et al.
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Fraver, Shawn
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Jonsson, Bengt-Gunnar
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Dynesius, M.
    Umeå University.
    Rydgård, M.
    The County Administration of Västra Götaland.
    Esseen, P.-A.
    Umeå University.
    Eighteen years of tree mortality and structural change in an experimentally fragmented Norway spruce forest2007Ingår i: Forest Ecology and Management, ISSN 0378-1127, E-ISSN 1872-7042, Vol. 242, nr 2-3, s. 306-313Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Long-term experimental forest fragmentation studies remain uncommon, despite their critical role in the advancement of ecological theory and conservation planning. In 1986 five circular forest fragments (1/16-1 ha) were exposed through clearcutting within an old-growth Norway spruce (Picea abies) forest in northern Sweden. Initial responses to fragmentation (1986-1991) showed very high tree mortality and structural degradation of the fragments. In the present study we re-inventoried these fragments to evaluate tree mortality patterns and structural changes occurring over a longer time period (1991-2004). The fragments can readily be viewed as harvest retention patches or 'woodland key habitats' (i.e., set-aside patches of high conservation value), allowing us to make inferences about the effectiveness of these novel conservation tools. Tree mortality rates dropped markedly (to 1.2-3.9%/year) compared to the initial responses, yet remained elevated over those of control plots in the nearby unfragmented forest (0.7%). Mortality increased with tree diameter, resulting in smaller-diameter, more homogenous stands. Mortality also generally increased with decreasing fragment size and was dependent of tree location within fragments. Standing death (45% of dead trees, 1991-2004) replaced uprootings (71%, 1986-1991) as the dominant mode of mortality. Numbers of dying and standing dead trees increased during the second sampling period, further adding to structural change and reduced stand density. Elevated tree mortality resulted in uncharacteristically high volumes of coarse woody debris. Results clearly show that adverse edge-related changes to forest structure and function persist up to two decades after fragmentation. Fragments of this size largely fail as remnants intended to maintain forest interior conditions and late-successional forest structure. However, when embedded within a harvested landscape, they: (1) provide abundant coarse woody debris and snags for deadwood-dependent species that risk extirpation in the surrounding matrix and (2) retain important structures for the developing stands.

  • 334.
    Jönsson, Mari
    et al.
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Jonsson, Bengt Gunnar
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Landscape-level synchrony of dead-wood input in samll set-asides of Norway spruce (Picea abies) forest: Implications for saproxylic populationsManuskript (preprint) (Övrigt vetenskapligt)
  • 335.
    Jönsson, Mari T
    et al.
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Jonsson, Bengt-Gunnar
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Assessing coarse woody debris in Swedish woodland key habitats: Implications for conservation and management2007Ingår i: Forest Ecology and Management, ISSN 0378-1127, E-ISSN 1872-7042, Vol. 242, nr 2-3, s. 363-373Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In the mainland Nordic countries and the Baltic States, the delineation and set-aside of woodland key habitats (WKHs) has been one important approach to conserving biodiversity outside traditional protected areas. Though the specifics of the key habitat concept differ from country to country, the intent is to set aside forest areas that (1) exhibit a low degree of exploitation, (2) host or potentially host red-listed species, and/or (3) contain old-growth characteristics (e.g. dead wood, large old trees) or other qualities considered valuable for maintaining biodiversity. However, it is still uncertain to what extent WKHs actually retain quantities and qualities of coarse woody debris (CWD) that are characteristic of old-growth forests. The Biodiversity Monitoring Programme (BMP) recently conducted a detailed inventory of 491 WKHs across Sweden, providing a large dataset with which to evaluate the effectiveness of the WKH program with respect to CWD. In the present study we analyze the BMP data and compare CWD volume and composition between WKHs, mature managed (stand age 81-120 years), overmature managed (age 121-140 years), and published findings from old-growth forests. The national average volume of CWD (standing and downed combined, m3/ha) was higher in WKHs (19.5) than the mature managed (9.3) and the overmature managed forest (12.2), yet was markedly lower than that reported from old-growth forests. CWD volumes in spruce-dominated WKHs had been reduced by 50-63% in the southern and middle boreal regions to 43-64% in the northern boreal region when compared to old-growth forests. In general, CWD amount, variability and quality were greater within WKHs in the boreal regions as opposed to the nemoral and boreonemoral regions in the south of Sweden. The majority of the WKHs (64%) contained key elements (very large and/or decayed dead wood known to be crucial habitat for many threatened wood-dependent species). Considering that these structures are largely absent from managed forests, WKHs have better retained some of the important features of old-growth forests when compared to the surrounding managed forest. WKHs are therefore valuable habitats for dead wood dependent species and representative focal areas for continued and future forest restoration and landscape planning. Our results confirm that large sun-exposed and burned dead wood are underrepresented CWD components within WKHs and emphasize the need to broaden the WKH definition to include locations containing these structures.

  • 336.
    Jönsson, Mari Therese
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    The importance of small forest set-asides for saproxylic biodiversity at stand- landscape- and regional scales2007Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
  • 337.
    Jöricke, Burglind
    et al.
    Uppsala universitet.
    Porten, Egmont
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    On the Continuity Principle2007Ingår i: Asian Journal of Mathematics, ISSN 1093-6106, E-ISSN 1945-0036, Vol. 11, nr 1, s. 167-178Artikel i tidskrift (Refereegranskat)
  • 338.
    Karlsson, S.
    et al.
    Department of Physical Chemistry, Åbo Akademi University, Porthaninkatu 3-5, Turku, FI-20500, Finland.
    Friman, R.
    Department of Physical Chemistry, Åbo Akademi University, Porthaninkatu 3-5, Turku, FI-20500, Finland.
    Lindström, Birger
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Backlund, S.
    Department of Physical Chemistry, Åbo Akademi University, Porthaninkatu 3-5, Turku, FI-20500, Finland.
    Self-assembly in the system decanoic acid-butylamine-water2001Ingår i: Journal of Colloid and Interface Science, ISSN 0021-9797, E-ISSN 1095-7103, Vol. 243, nr 1, s. 241-247Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The phase behavior of alkanoic acid-alkylamine mixtures in water is mainly dictated by a proton transfer from the acid to the amine. For an asymmetric distribution of carbon atoms in the alkyl chains, the result will be an ionic surfactant with an organic counter-ion. In this study the phase diagram at 298.2 K for the ternary system decanoic acid-butylamine-water has been determined. The phase diagram is dominated by a large isotropic solution region. The selfdiffusion, viscosity, and conductivity measurements in the solution phase for an equimolecular ratio between the acid and the amine indicate a continuous transition from aqueous spherical mixed micelles to highly interacting hydrated acid-amine complexes passing through a bicontinuous region. One liquid crystalline lamellar phase, existing at excess acid, has been found. The small angle Xray scattering results indicate that the amine, due to its slightly amphiphilic character, is distributed between water and the bilayer.

  • 339.
    Karlsson, Staffan
    et al.
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Andersson, Fredrik
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Breistein, Palle
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Hedenström, Erik
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Synthesis of butenolides recently isolated from marine microorganisms2007Ingår i: Tetrahedron Letters, ISSN 0040-4039, Vol. 48, nr 44, s. 7878-7881Artikel i tidskrift (Refereegranskat)
  • 340.
    Karlsson, Staffan
    et al.
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Han, F
    Högberg, Hans-Erik
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Caldirola, P
    trans-3,4-Disubtituted Pyrrolidines by 1,3-Dipolar Cycloaddition: Enantioselective Approaches and their Limitations1999Ingår i: Tetrahedron: Asymmetry, ISSN 0957-4166, Vol. 10, nr 13, s. 2605-2616Artikel i tidskrift (Refereegranskat)
  • 341.
    Karlsson, Staffan
    et al.
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Hedenström, Erik
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Sex Pheromone of the Pine Sawfly Macrodiprion nemoralis: Stereoselective Synthesis of the Sixteen Stereoisomers of 3,7,9-Trimethyl-2-tridecyl Acetate1999Ingår i: Acta Chemica Scandinavica, ISSN 0904-213X, Vol. 53, nr 8, s. 620-630Artikel i tidskrift (Refereegranskat)
  • 342.
    Karlsson, Staffan
    et al.
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Högberg, Hans-Erik
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Asymmetric 1,3-dipolar cycloadditions for the construction of enantiomerically pure heterocycles. A review2001Ingår i: Organic preparations and procedures international, ISSN 0030-4948, E-ISSN 1945-5453, Vol. 33, nr 2-3, s. 105-172Artikel, forskningsöversikt (Refereegranskat)
  • 343.
    Karlsson, Staffan
    et al.
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Högberg, Hans-Erik
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Catalytic enantioselective 1,3-dipolar cycloaddition of nitrones to cyclopent-1-enecarbaldehyde2002Ingår i: Tetrahedron: Asymmetry, ISSN 0957-4166, Vol. 13, nr 9, s. 923-926Artikel i tidskrift (Refereegranskat)
  • 344.
    Karlsson, Staffan
    et al.
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Högberg, Hans-Erik
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Diastereoselective addition of chiral azomethine ylides to cinnamoyl moieties, attached to chiral auxiliaries2001Ingår i: Tetrahedron: Asymmetry, ISSN 0957-4166, Vol. 12, nr 14, s. 1975-1976Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Doubly diastereoselective 1,3-dipolar cycloadditions of chiral azomethine ylides to cinnamoyl moieties, attached to chiral auxiliaries, were investigated. The resulting trans-3,4-disubstituted pyrrolidines were obtained in diastereomeric ratios of up to 78:22. The influence on this ratio by the constitution of the chiral ylide was found to be rather small.

  • 345.
    Karlsson, Staffan
    et al.
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Högberg, Hans-Erik
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Diastereoselective addition of chiral azomethine ylides to cyclic alpha,beta-unsaturated N-enoylbornanesultams2002Ingår i: Journal of the Chemical Society. Perkin Transactions 1, ISSN 1472-7781, Vol. 2002, nr 8, s. 1076-1081Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Doubly diastereoselective 1,3-dipolar cycloaddition reactions of chiral non-racemic azomethine ylides to cyclic five-and six-membered α,β-unsaturated N-enoylbornanesultams were carried out. When suitable solvents were used, the fused bicyclic adducts formed were obtained in good diastereoselectivity. Moreover, a change of the absolute configuration of the starting ylide precursor reversed the diastereoselectivity of some such reactions. Cleavage of the chiral auxiliary of the cycloadducts furnished amino alcohols and a β-amino ester. The latter was transformed into a known precursor of an antibacterial compound.

  • 346.
    Karlsson, Staffan
    et al.
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Högberg, Hans-Erik
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Enantiomerically pure trans-3,4-disubstituted tetrahydrothiophenes from diastereoselective thiocarbonyl ylide addition to chiral alpha,beta-unsaturated amides1999Ingår i: Organic Letters, ISSN 1523-7060, Vol. 1, nr 10, s. 1667-1669Artikel i tidskrift (Refereegranskat)
  • 347.
    Karlsson, Staffan
    et al.
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Högberg, Hans-Erik
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Organocatalysts Promote Enantioselective 1,3-Dipolar Cycloadditions of Nitrones with 1-Cycloalkene-1-carboxaldehydes2003Ingår i: European Journal of Organic Chemistry, ISSN 1434-193X, E-ISSN 1099-0690, Vol. 2003, nr 15, s. 2782-2791Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In the presence of enantiopure organocatalysts, 1-cycloalkene-1-carboxaldehydes and various nitrones furnished fused isoxazolidines. Thus, some chiral pyrrolidinium salts catalyzed the formation of such cycloadducts in high diastereo- and enantioselectivity (up to 92% ee). The predominant diastereomer, the exo one, was mostly obtained in excellent diastereoselectivity (> 99:1 dr). Furthermore, after recrystallization of one of the cycloadducts, this was obtained enantiomerically pure (> 99% ee). The absolute configuration of one of the cycloadducts was determined. 

  • 348.
    Karlsson, Staffan
    et al.
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Högberg, Hans-Erik
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Pheromones of Pine Sawflies: Synthesis of a Pure (2S,3R)-3-Methylalkan-2-ol Stereoisomer via an Asymmetric 1,3-Dipolar Cycloaddition; Preparation of a Pheromone Component of Macrodiprion nemoralis2000Ingår i: Synthesis, ISSN 0039-7881, Vol. 2000, nr 13, s. 1863-1867Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This paper presents a new approach to the preparation of enantiomerically pure (2S,3R)-3-methylalkan-2-ols, the esters of which are sex pheromones of several pine sawflies. Thus, an asymmetric 1,3-dipolar cycloaddition between a sulfur containing 1,3-dipole and a dipolarophile attached to (1R)-camphorsultam containing a vinyl ether functionality furnished a 90:10 diastereomeric mixture of trans-3,4-disubstituted tetrahydrothiophene amides. The major one was converted to an enantiomerically pure tetrahydrothienylmethyl bromide, which was coupled with a monoalkylated dithiane unit. After Raney nickel reduction (2S,3R,7R,9S)-3,7,9-trimethyltridecan-2-ol was obtained, the acetate of which is the attractant sex pheromone component of Macrodiprion nemoralis. Because this new approach is quite efficient it can be valuable for the synthesis of similar compounds.

  • 349.
    Karlsson, Staffan
    et al.
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Högberg, Hans-Erik
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Synthesis of enantiomerically pure 4-substituted pyrrolidin-3-ols via asymmetric 1,3-dipolar cycloaddition2001Ingår i: Tetrahedron: Asymmetry, ISSN 0957-4166, Vol. 12, nr 14, s. 1977-1982Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Asymmetric 1,3-dipolar cycloadditions of chiral azomethine ylides to 3-benzyloxy-substituted alkenoylcamphorsultams are described. trans-3,4-Disubstituted pyrrolidines containing a protected hydroxyl group at C(4) of the pyrrolidine ring are obtained in high diastereomeric ratios. Such compounds can serve as chiral building blocks for the syntheses of enantiopure bioactive pyrrolidines. This is exemplified by a short synthetic route to a known glycosidase inhibitor, (3R,4R)-4-(hydroxymethyl)pyrrolidin-3-ol and its enantiomer.

  • 350.
    Klang, Anders
    et al.
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för teknik, fysik och matematik.
    Vikman, Per-Åke
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Brattebo, H
    (Norwegian University of Science and Technology) (Industrial Ecology).
    Sustainable management of demolition waste: an integrated model for the evaluation of environmental, economic and social aspect2003Ingår i: Resources, Conservation and Recycling, ISSN 0921-3449, E-ISSN 1879-0658, Vol. 38, nr 4, s. 317-334Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A model is presented for evaluating waste management systems for their contribution to a sustainable development, including environmental, economic and social aspects. The model was tested in a case-study, where groups of long term unemployed people were offered both education on environmental issues and practical work with the recovery and recycling of building and demolition waste as a form of vocational development. Application of the suggested model revealed the overall effects on sustainability of different methods of waste management. In addition, negative aspects of the systems analysed were identified, which led to discussions about possible improved practices within the waste management systems. Two of the waste management systems investigated (the recycling of steel and re-use of sanitary porcelain) showed a potential contribution to sustainable development in all of the aspects studied. Preparing bricks for re-use showed the largest potential for eco-efficiency, but had negative effects on sustainability from the social perspective of health and the working environment. The possibility of further use of the model and the remaining obstacles to such analyses are discussed. One observation is that the data collection needed to perform this kind of sustainability analysis is resource-demanding, and that it would therefore be better to identify a smaller number of key indicators.

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