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  • 351.
    Svensson, Dag
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Creating High Fat Emulsions with Mango, Rapeseed Oil and Soy Lecithin2013Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Food inevitably plays a vital role in our lives and is of great importance to our health and wellbeing. With increasing age, it is equally important to achieve adequate nutrition to prevent and alleviate age-related diseases. One problem is that far too many older adults find it difficult to eat enough nutritious food which in the long term may lead to malnutrition. With an increasing life expectancy the older population is growing and the problem with malnutrition is of great concern. Malnutrition can be caused by many different factors which make it difficult to find a single unique solution to the problem. Oral nutritional supplementation is one approach which has proved to be useful for improving the nutritional intake. This paper examines the possibility of creating high fat fruit emulsion with mango puré, rapeseed oil and lecithin, using simple blending equipment.  The puré-like products were evaluated for emulsion stability by a storage test, oil droplet size by a light microscope and light scattering device, viscosity by a viscometer, sensory properties by Flavoring profiling. Furthermore the nutritional values were calculated.  Successful emulsions were created using up to 50 g/100g rapeseed oil with adequate emulsion stability without lecithin. The energy content of the highest fat emulsion was 475kcal/100g. The quantities of lecithin used in these products reduced the oil droplet size but lowered the emulsion stability perhaps by depleting the stabilizing effect of mango originated particles. The lecithin made the product more viscous, also the oily and creamy/Rich mouth-feel were perceived higher with increasing lecithin. In these products and with the quantities used the lecithin was redundant. Further development of similar products but with addition of protein and perhaps sugar, to enhance flavor, should be of high interest.

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    Creating High Fat Emulsions with Mango, Rapeseed Oil and Soy Lecithin
  • 352.
    Svensson, Fredric
    Linnaeus University, Faculty of Health and Life Sciences, Department of Chemistry and Biomedical Sciences.
    Do the grasshoppers Tetrix subulata and T. undulata use pheromones?2013Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
  • 353.
    Svensson, Fredric
    Linnaeus University, Faculty of Health and Life Sciences, Department of Chemistry and Biomedical Sciences.
    Identification, Synthesis and Characterization of Semiochemicals of some Forest Beetles2015Independent thesis Advanced level (degree of Master (Two Years)), 30 credits / 45 HE creditsStudent thesis
    Abstract [en]

    This work consists of three parts. Part one deals with the syntheses of a number of common Cerambycidae and bark beetle semiochemicals. Additionally, syntheses for three new suspected Cerambycidae semiochemicals were developed. In part two, the elution order and Kovats retention indices of various bark beetle associated semiochemicals were determined on an enantioselective GC-column. In part three, SPME/GC-MS analyses of bark beetle associated fungi cultivations on terpenes were undertaken to find fungal degradation products with known electrophysical activity to bark beetles. A large number of bark beetle semiochemicals were found, including two bark beetle pheromones.

  • 354.
    Svensson, Karin
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Development of a Method for Measurement of the Mechanical Stability of Granulated Milk Powders2012Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Barry Callebaut Sweden AB manufactures a large number of powder mixes for vending and coffee machines. It is important that the powder obtains good flowability, good instant properties and reduced tendency to cake during storage. Agglomeration or granulation of powder can be used to improve these properties. Agglomerated or granulated powder is often fragile and can be destroyed during handling and shipping, leading to formation of smaller particles, fines. Fines have in general a tendency to cake and poorer instant properties. Therefore it is important that the powders have a good mechanical strength.The purpose of this work was to develop a method for investigating the stability of granulated milk powders to mechanical stress using the Auto – Friability Tester – PTF10 E. Two different milk powders were investigated by varying effects of rotation speed, runtime, sample size and the amount of added ball bearings. The attrition of the powder samples were analyzed by an ALPINE Air Jet Sieve.The results showed that the degree of attrition was dependent on the settings used and the powder samples were affected by the sieving which needs to be taken into consideration.In conclusion, it is possible to develop the methodology further but more measurements are needed to improve precision and accuracy. 

  • 355.
    Svensson, Lovisa
    et al.
    Uppsala University.
    Artursson, Karin
    National Veterinary Institute.
    Berg, Charlotte
    Swedish University of Agricultural Sciences.
    Nicholls, Ian A.
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Infection Ecology and Epidemiology, IEE Network - A New Interdisciplinary Collaboration of Researchers in Zoonotic Infections2011In: EcoHealth, vol. 7, Supplement 1, Springer, 2011, Vol. 7, p. S80-S81Conference paper (Refereed)
    Abstract [en]

    Combating zoonoses effectively requires an approach where researchers take in account the ‘‘one health’’ concepts. TheInfection Ecology and Epidemiology, IEE network was started to stimulate interdisciplinary projects with potential toincrease knowledge of the emergence, spread and effects of infectious disease in humans, domestic animals and wildlife. Themain objective for IEE is to provide a platform where researchers from multiple medical and ecological disciplines caninteract and create synergies through collaboration, annual meetings and workshops.The first IEE meeting, in March 2010, served as a unique opportunity for Swedish researchers (veterinarians, physicians,ecologists, epidemiologists and others with relevant backgrounds) interested in infectious diseases to interact over disci-plinary boundaries. The meeting was a great success with almost 100 participants from across the nation. Since the meetinginterest in IEE has continued to increase and the number of researchers supporting IEE now has now passed 150.The projects within the IEE network range from antibiotic resistance in bacteria to the genetic virology of vector-bornepathogens, zoonotic viroses and gastrointestinal pathogens. The rationale is not to build up new laboratory facilities, but touse and collaborate within already established research structures. Within the network we have access to original samples ofanimal, human and environmental origin for collaborative projects for detection and characterization of viruses andbacteria. We hope that the IEE network will provide a sustainable platform for interdisciplinary collaborations and a stronginternational research environment for research on zoonotic infections.

  • 356.
    Sørud, Mai
    et al.
    Krüger Veolia Water Technologies, Denmark.
    Nielsen, Katrine
    Technical University of Denmark, Denmark.
    Skau Damskier, Sophie
    Nordvand A/S, Denmark.
    Torpenholt Jørgensen, Alex
    Krüger Veolia Water Technologies, Denmark.
    Fjendbo Petersen, Mette
    Krüger Veolia Water Technologies, Denmark.
    Kofoed Rasmussen, Lone
    Gladsaxe kommune, Denmark.
    Mikkelsen, Peter Steen
    Technical University of Denmark, Denmark.
    Eriksson, Eva
    Technical University of Denmark, Denmark.
    DEMFIL - treatment of stormwater for recreational use2013In: Proceedings of the 13th Nordic Wastewater Conference, Malmö: Svenskt Vatten , 2013Conference paper (Refereed)
    Abstract [en]

    Decoupling of stormwater (road runoff) in a residential area has been implemented in order to reduce flooding and to increase the hydraulic capacity of a lake with a high recreational value. The object here was to evaluate a disc filter technology in combination with a green polymer for flocculation for its feasibility of particle removal. Secondary, the particulate pollution in the separate road runoff should be assessed.The road runoff was found not to be highly contaminated with particle pollution, here measured as turbidity and total suspended solids (TSS). The particles were generally small (< 10 μm) and negatively charged. The disc filtration was hampered during the winter season and by the large fraction of small particles, but supplementing it with flocculation increased the removal efficiencies. The inlet particle concentrations (mg/L) affected the removal efficiencies, and events with inlet concentrations < 10 mg TSS/L or FNU had no statistically significant removal of the particle pollution whereas the events with the highest concentrations yielded among the highest removal efficiencies. The green polymer is as efficient as previously tested commercial coagulant/ flocculent and the disc technology is promising but need to be further tested with higher hydraulic loadings.

  • 357.
    Taghiyari, Hamid Reza
    et al.
    Shahid Rajaee Teacher Training University, Iran.
    Tajvidi, Mehdi
    University of Maine, USA.
    Taghiyari, Reyhaneh
    Payame Noor University, Iran.
    Mantanis, George
    University of Thessaly, Greece.
    Esmailpour, Ayoub
    Shahid Rajaee Teacher Training University, Iran.
    Hosseinpourpia, Reza
    Linnaeus University, Faculty of Technology, Department of Forestry and Wood Technology.
    Nanotechnology for wood quality improvement and protection2020In: Nanomaterials for Agriculture and Forestry Applications: Micro and Nano Technologies / [ed] Azamal Husen and Mohammad Jawaid, Elsevier, 2020, p. 469-489Chapter in book (Refereed)
    Abstract [en]

    Wood is a natural renewable material with unique properties helping mankind to build and develop its communities since the genesis of human on the Earth. Moreover, wood/cellulosic composites provide the opportunity to utilize low-density wood species and agricultural materials that are basically not suitable for structural applications. Although wood is considered irreplaceable, it has some disadvantages narrowing its applications and limiting its service life. These disadvantages mainly include its susceptibility to water and water vapor, biological deteriorating fungi, insects, termites, and marine borers. The present chapter tries to summarize some main areas in which nanotechnology is being used to improve wood and lignocellulosic-based composite panels. Moreover, some new applications and capabilities of this precious natural material are also brought into perspective, areas such as transparent wood, self-cleaning coatings, and smart windows. Though some areas have been thoroughly studied, much potential still exists for further studies and commercialization.

  • 358.
    ten Siethoff, Lasse
    et al.
    Linnaeus University, Faculty of Health and Life Sciences, Department of Chemistry and Biomedical Sciences.
    Lard, Mercy
    Lund university.
    Generosi, Johanna
    Lund university.
    Andersson, Håkan S.
    Linnaeus University, Faculty of Health and Life Sciences, Department of Chemistry and Biomedical Sciences.
    Linke, Heiner
    Lund university.
    Månsson, Alf
    Linnaeus University, Faculty of Health and Life Sciences, Department of Chemistry and Biomedical Sciences.
    Molecular Motor Propelled Filaments Reveal Light-Guiding in Nanowire Arrays for Enhanced Biosensing2014In: Nano letters (Print), ISSN 1530-6984, E-ISSN 1530-6992, Vol. 14, no 2, p. 737-742Article in journal (Refereed)
    Abstract [en]

    Semiconductor nanowire arrays offer significant potential for biosensing applications with optical read-out due to their high surface area and due to the unique optical properties of one-dimensional materials. A challenge for optical read-out of analyte-binding to the nanowires is the need to efficiently collect and detect light from a three-dimensional volume. Here we show that light from fluorophores attached along Several mu m long vertical Al2O3 coated gallium phosphide nanowires couples into the wires, is guided along them and emitted at the tip. This enables effective collection of light emitted by fluorescent analytes located at different focal planes along the nanowire. We unequivocally demonstrate the light-guiding effect using a novel method whereby the changes in emitted fluorescence intensity are observed when fluorescent cytoskeletal filaments are propelled by molecular motors along the wires. The findings are discussed in relation to nanobiosensor developments, other nanotechnological applications, and fundamental studies of motor function.

  • 359.
    Timmer, Brian J. J.
    et al.
    KTH Royal instute of technology, Sweden.
    Ramström, Olof
    Linnaeus University, Faculty of Health and Life Sciences, Department of Chemistry and Biomedical Sciences. KTH Royal instute of technology, Sweden;Univ Massachusetts, USA.
    Acid-Assisted Direct Olefin Metathesis of Unprotected Carbohydrates in Water2019In: Chemistry - A European Journal, ISSN 0947-6539, E-ISSN 1521-3765, Vol. 25, no 63, p. 14408-14413Article in journal (Refereed)
    Abstract [en]

    The ability to use unprotected carbohydrates in olefin metathesis reactions in aqueous media is demonstrated. By using water-soluble, amine-functionalized Hoveyda-Grubbs catalysts under mildly acidic aqueous conditions, the self-metathesis of unprotected alkene-functionalized alpha-d-manno- and alpha-d-galactopyranosides could be achieved through minimization of nonproductive chelation and isomerization. Cross-metathesis with allyl alcohol could also be achieved with reasonable selectivity. The presence of small quantities (2.5 vol %) of acetic acid increased the formation of the self-metathesis product while significantly reducing the alkene isomerization process. The catalytic activity was furthermore retained in the presence of large amounts (0.01 mm) of protein, underlining the potential of this carbon-carbon bond-forming reaction under biological conditions. These results demonstrate the potential of directly using unprotected carbohydrate structures in olefin metathesis reactions under mild conditions compatible with biological systems, and thereby enabling their use in, for example, drug discovery and protein derivatization.

  • 360.
    Tjörnbo, Jonas
    University of Kalmar, School of Pure and Applied Natural Sciences.
    Mätning av syrehalt i öl vid olika processteg2009Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    ABSTRACT

     

    Today the market and consumers demand good and even quality of beer. Most people find factors as price, durability, origin of manufacturing and sensory pleasure important when choosing among an abundance of goods.

     

    What people generally don’t know, is what it takes to produce an even quality beer that tastes exactly the same year after year. There are so many things that can spoil a batch of beer. One important factor is the oxygen level. If it’s too high in the product, the beer will go cloudy and produce off-flavours.

     

    This is what my objective has been during this project; to evaluate how extensive the oxygen pickup is during different steps of beer making. Everybody knows that we need oxygen to survive. But when it comes to later stages of beer making, its presence is absolutely not wanted.

     

    To find out the oxygen level in different steps of beer making, an oxygen meter that can measure very small amounts of dissolved oxygen in fluids was used. By connecting the instrument to examination taps before and after different process steps, I could determine exactly how big the oxygen pickup had been at a specific point.

     

    The outcome of the oxygen level measuring shows inconsistency when comparing data from a single process that has been measured on different dates. Though there are trends showing a pickup of oxygen during the processes from emptying the storage tanks to filling the beer into bottles or cans.

     

    Further measurements need to be done during the beer production, to evaluate the magnitude of oxygen pickup to the product and to get more precise values.

     

    This short project has been limited to beer-production, and filling it to cans or bottles. But there is also a need for following up the filling of KEGs and trucks. Mapping out the oxygen levels during cider production also needs to be done.

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  • 361.
    Todde, Guido
    et al.
    Linnaeus University, Faculty of Health and Life Sciences, Department of Chemistry and Biomedical Sciences.
    Friedman, Ran
    Linnaeus University, Faculty of Health and Life Sciences, Department of Chemistry and Biomedical Sciences.
    Activation and Inactivation of the FLT3 Kinase: Pathway Intermediates and the Free Energy of Transition2019In: Journal of Physical Chemistry B, ISSN 1520-6106, E-ISSN 1520-5207, Vol. 123, no 26, p. 5385-5394Article in journal (Refereed)
    Abstract [en]

    The aberrant expression of kinases is often associated with pathologies such as cancer and autoimmune diseases. Like other types of enzymes, kinases can adopt active and inactive states, where a shift toward more stable active state often leads to disease. Dozens of kinase inhibitors are, therefore, used as drugs. Most of these bind to either the inactive or active state. In this work, we study the transitions between these two states in FLT3, an important drug target in leukemias. Kinases are composed of two lobes (N- and C-terminal lobes) with the catalytic site in-between. Through projection of the largest motions obtained through molecular dynamics (MD) simulations, we show that each of the end-states (active or inactive) already possess the ability for transition as the two lobes rotate which initiates the transition. A targeted simulation approach known as essential dynamics sampling (EDS) was used to speed up the transition between the two protein states. Coupling the EDS to implicit-solvent MD was performed to estimate the free energy barriers of the transitions. The activation energies were found in good agreement with previous estimates obtained for other kinases. Finally, we identified FLT3 intermediates that assumed configurations that resemble that of the c-Src nonreceptor tyrosine kinase. The intermediates show better binding to the drug ponatinib than c-Src and the inactive state of FLT3. This suggests that targeting intermediate states can be used to explain the drug-binding patterns of kinases and for rational drug design.

  • 362.
    Todde, Guido
    et al.
    Linnaeus University, Faculty of Health and Life Sciences, Department of Chemistry and Biomedical Sciences.
    Friedman, Ran
    Linnaeus University, Faculty of Health and Life Sciences, Department of Chemistry and Biomedical Sciences.
    Conformational modifications induced by internal tandem duplications on the FLT3 kinase and juxtamembrane domains2019In: Physical Chemistry, Chemical Physics - PCCP, ISSN 1463-9076, E-ISSN 1463-9084, Vol. 21, no 34, p. 18467-18476Article in journal (Refereed)
    Abstract [en]

    he aberrant expression of FLT3 tyrosine kinase is associated primarily with acute myeloid leukaemia. This blood malignancy is often related to the onset of internal tandem duplications (ITDs) in the native sequence of the protein. The ITDs occur mainly in the juxtamembrane domain of the protein and alter the normal activity of the enzyme. In this work, we have studied the native form of FLT3 and six mutants by molecular dynamics simulations. The catalytic activity of FLT3 is exerted by the tyrosine kinase domain (KD) and regulated by the juxtamembrane (JM) domain. Analysis of the dynamics of these two domains have shown that the introduction of ITDs in the JM domain alters both structural and dynamic parameters. The presence of ITDs allowed the protein to span a larger portion of the conformational space, particularly in the JM domain and the activation loop. The FLT3 mutants were found to adopt more stable configurations than the native enzyme. This was due to the different arrangements assumed by the JM domain. Larger fluctuations of the activation loop were found in four of the six mutants. In the native FLT3, the key residue Tyr(572) is involved in a strong and stable interaction with an ion pair. This interaction, which is thought to keep the JM in place hence regulating the activity of the enzyme, was found to break in all FLT3 mutants.

  • 363.
    Unelius, C. Rikard
    et al.
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Bohman, Björn
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Lorenzo, Marcelo
    Laboratório de Triatomíneos e Epidemiologia da Doença de Chagas. Centro de Pesquisas René Rachou/FIOCRUZ, Belo Horizonte, BRAZIL.
    Tröger, A
    Univ of Hamburg.
    Franke, S
    Univ of Hamburg.
    Francke, Wittko
    Univ of Hamburg.
    (4S,5S)-2,2,4-Triethyl-5-methyl-1,3-dioxolane: A New Volatile Released by a Triatomine Bug2010In: Organic Letters, ISSN 1523-7060, E-ISSN 1523-7052, Vol. 12, no 24, p. 5601-5603Article in journal (Refereed)
    Abstract [en]

    Adults of the triatomine bug, Triatoma brasiliensis release 2,2,4-triethyl-5-methyl-1,3-dioxolane (1) as a mixture of the (4S,5S)- and (4R,5R)-enantiomers in a ratio of 4:1. Among the volatile acetals identified from insects so far, this is the first example resulting from an intermolecular condensation of a carbonyl moiety and a diol substructure.

  • 364.
    Unelius, C. Rikard
    et al.
    Linnaeus University, Faculty of Health and Life Sciences, Department of Chemistry and Biomedical Sciences.
    Bohman, Björn
    Linnaeus University, Faculty of Health and Life Sciences, Department of Chemistry and Biomedical Sciences. Univ Western Australia, Australia.
    Nordlander, Goran
    Swedish University of Agricultural Sciences.
    Comparison of Phenylacetates with Benzoates and Phenylpropanoates as Antifeedants for the Pine Weevil, Hylobius abietis2018In: Journal of Agricultural and Food Chemistry, ISSN 0021-8561, E-ISSN 1520-5118, Vol. 66, no 44, p. 11797-11805Article in journal (Refereed)
    Abstract [en]

    This study concludes an extensive investigation of antifeedants for the pine weevil, Hylobius abietis (Coleoptera: Curculionidae), an economically important pest of planted conifer seedlings. Building on the previously reported antifeedant effects of benzoates and phenylpropanoids (aromatic compounds with one- or three-carbon-atom substituents on the benzene ring), we here report the antifeedant effects of compounds with two-carbon-atom side chains (i.e., phenylacetates). We also present new results; the best antifeedants from the benzoate class were tested at 10-fold lower concentrations in order to find the optimal antifeedants. Generally, for all three compound classes, efficient antifeedants were found to have one or two methyl, chloro, or methoxy substituents on the aromatic ring. For monosubstituted phenylpropanoids, the substituent preferably should be in the para-position. In the search for synergistic antifeedant effects among the three compound classes, combinations of compounds from the three classes were tested in binary and ternary mixtures.

  • 365.
    Unelius, C. Rikard
    et al.
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    El-Sayed, Ashraf
    The New Zealand Institute for Plant & Food Research Ltd.
    Twidle, Andrew
    The New Zealand Institute for Plant & Food Research Ltd.
    Bunn, Barry
    The New Zealand Institute for Plant & Food Research Ltd.
    Zaviezo, Tania
    Universidad Católica de Chile, Santiago, Chile.
    Flores, Fernanda
    Pontificia Universidad Católica de Valparaíso, , Chile.
    Bell, Vaughn
    The New Zealand Institute for Plant & Food Research Ltd.
    Bergmann, Jan
    Pontificia Universidad Católica de Valparaíso, , Chile.
    The Absolute Configuration of the Sex Pheromone of the Citrophilous Mealybug, Pseudococcus calceolariae2011In: Journal of Chemical Ecology, ISSN 0098-0331, E-ISSN 1573-1561, Vol. 37, no 2, p. 166-172Article in journal (Refereed)
    Abstract [en]

    The absolute configuration of the sex pheromone of the Citrophilous mealybug, Pseudococcus calceolariae, has been identified as (1R,3R)-2,2-dimethyl-3-(2-methylprop-1-enyl)cyclopropyl)methyl (R)-2-acetoxy-3-methylbutanoate. The absolute configuration was determined by NMR, derivatization reactions, chiral GC/MS analysis, and comparison with synthetic chiral reference compounds. The correct structure was further proven by trap catches of adult male mealybugs in field trials. Traps baited with 1000 µg of the pheromone caught 36-fold more males than traps baited with virgin females. A mixture of stereoisomers of the pheromone can be used in field trapping experiments. A comparison with the structures of other sex pheromones of mealybugs is presented.

  • 366.
    Unelius, C. Rikard
    et al.
    The Horticulture & Food Research Institute of New Zealand Limited (HortResearch), P.O. Box 51 Lincoln, New Zealand.
    Townsend, R J
    Mundy, D C
    Manning, L M
    Jackson, T A
    Suckling, D M
    Trap Comparisons and Lures for Monitoring Grass Grub, Costelytra zealandica2008In: New Zealand Plant Protection, ISSN 1175-9003, Vol. 61, p. 215-221Article in journal (Refereed)
  • 367.
    Unelius, Rikard
    Organic Chemistry, KTH.
    Pheromone Synthesis: Conjugated Diene Systems and Oxygenated Carene Derivatives1989Doctoral thesis, comprehensive summary (Other academic)
  • 368.
    Vidal Carulla, Clara
    et al.
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Adbo, Karina
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Using Cultural-Historical Theory to Design and Assess a Chemistry Play-Based Learning Intervention2019In: Cultural-Historical Psychology, ISSN 1816-5435, E-ISSN 2224-8935, Vol. 15, no 4, p. 35-43Article in journal (Refereed)
    Abstract [en]

    This study has been performed in Sweden, where the preschool curriculum states that children's understanding of simple chemical processes is a goal to strive towards [13]. However, uncertainty within the current preschool practice exists and has been described by B. Sundberg et al. [20]. Motivated by the lack of scientific literature on what chemistry content is suitable for preschool children and how to introduce it, this study aims to tackle how abstract concepts like "atoms" and "molecules" can be introduced to preschool children. With this purpose, a play-based learning intervention was designed, following the cultural- historical model for preschool science education proposed by M. Fleer [7], and implemented in two Swedish preschools, dividing a total of 20 three-years-old children into four groups of five children each. Data were collected in the form of video-recordings of the sessions and analysed following the principles from the experimental-genetic method summarized by N. Veresov [23]. Results are presented in the form of vignettes that illustrate significant moments from the intervention, together with discussion of how the social situation of development, the zone of actual development and the mediating tools facilitate the children in starting to talk about atoms.

  • 369.
    Vikfors, Ida
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Utveckling av recepturen för Rydbergs räksallad med avsikt att förbättra dess hållbarhet2012Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Att producera en livsmedelsprodukt med lång hållbarhet är både fördelaktigt för producenten och konsumenten.  Rydbergs räksallad är en majonnäsbaserad sallad innehållande synliga bitar av räkor och vita betor. Förruttnelsen av majonnäsbaserade sallader sker oftast på grund av produktförstörande mjölksyrabakterier och jäst. Dessa har förmågan att tillväxa vid lågt pH, låga temperaturer och låg vattenaktivitet, vilket gör dem till en utmaning för livsmedelsindustrin att undvika. På grund av deras starka motståndskraft i livsmedel, är det nödvändigt att tillsätta konserveringsmedel till de drabbade produkterna. Natriumbensoat och kaliumsorbat är vanliga konserveringsmedel i majonnäsbaserade produkter och har sin största effektivitet vid låga pH. Syftet med föreliggande examensarbete var att validera och undersöka problemen i hållbarheten hos Rydbergs räksallad. Därför, med hjälp av justering av pH och koncentrationer av konserveringsmedlen natriumbensoat och kaliumsorbat, fokuserar examensarbetet på att försöka förlänga hållbarheten hos Rydbergs räksallad.Mikrobiologiska analyser visade att det är de vita betorna i räksalladen som troligen begränsar räksalladens hållbarhet. Sänkt pH till 3,5 och 3,0 hos de vita betorna gav en märkbar reduktion i tillväxten av aeroba mikroorganismer. Ökad koncentration av natriumbensoat och kaliumsorbat, med avsikt att minska halten av produktförstörande mikroorganismer, gav liknande samband som analysen med justerat pH. En slutsats av studien är att längre hållbarhet hos Rydbergs räksallad fås genom att antingen sänka pH till 3,5–3,0 eller öka halterna av konserveringsmedel hos betorna.

  • 370. Vitta, A.C.R.
    et al.
    Bohman, Björn
    University of Kalmar, School of Pure and Applied Natural Sciences.
    Unelius, C. Rikard
    University of Kalmar, School of Pure and Applied Natural Sciences.
    Lorenzo, Marcelo
    Behavioral and Electrophysiological Responses of Triatoma brasiliensis Males to Volatiles Produced in the Metasternal Glands of Female2009In: Journal of Chemical Ecology, ISSN 0098-0331, E-ISSN 1573-1561, Vol. 35, no 10, p. 1212-1221Article in journal (Refereed)
    Abstract [en]

    In many insects, mate finding is mediated by volatile sex pheromones, but evidence for this phenomenon in triatomines (Heteroptera: Reduviidae) is still fragmentary. Recently, it was shown that metasternal glands (MGs) are involved in producing signals related to the sexual communication of Triatoma infestans and Rhodnius prolixus. Based on this, we tested whether MG volatiles could be involved in the sexual communication of Triatoma brasiliensis. Odor-mediated orientation responses were studied by using a T-tube olfactometer. These tests showed that males exhibit positive anemotaxis when confronted with adult odor-laden air currents. Moreover, females that had their metasternal glands occluded did not elicit significant orientation by males. Compounds produced by the MGs of T. brasiliensis females were identified by means of SPME, GC-FID, and GC-MS, with achiral and chiral columns. All substances identified were ketones and alcohols, and similar compound profiles were found in the secretions produced by both sexes. The most abundant compounds identified were 3-pentanone, followed by (4R)-methyl-1-heptanol, 3-pentanol, and (2S)-methyl-1-butanol. In addition, GC-EAD recordings showed that the antennae of males responded to several of the main components of female MG secretions. Our results showed that compounds produced by the MGs of T. brasiliensis females are involved in the sexual communication of this species.

  • 371.
    Wagner, Ylva
    Linnaeus University, Faculty of Health and Life Sciences, Department of Chemistry and Biomedical Sciences.
    Conformational Change of β2-glycoprotein I: Evaluation of Difference in Binding Capacity of Autoantibodies to Open and Closed Forms of β2-glycoprotein I2013Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Antiphospolipidsyndrome (APS) is one of the most common autoimmune diseases characterized bythrombosis, fetal loss and presence of antiphospholipid antibodies. In APS research the antibodies of biggestinterest are anti-β2-glycoprotein I antibodies (Aβ2GPIA). β2-glycoprotein I (β2GPI)is a plasma protein which becomes activated and obtains a open structure incontact with negative charged surface molecules such as phospholipids. Inactiveβ2GPI has a closed, circular shape which can’t bind autoantibodies. Thereis no golden standard for APS diagnosing and the methods used often giveinconsistent results. The purpose of this examination project work was toconvert β2GPI into the open and closed forms, respectively, by dialyzing againsthigh ionic strength, low and high pH and determine if there is any differencein binding capacity between the two forms and Aβ2GPIAon a microtiter plate.                                               

    The binding capacity was tested inan ELISA (enzyme-linkedimmunosorbent assay) using purified IgG from patient sera and thedifferent conformational forms of β2GPI. An ELISA for measuring of Aβ2GPIAon several patient samples was also performed.              

    No difference in binding capacitycould be detected which might be explained by that the conversion of β2GPI was unsuccessful.Perhaps no difference can be measured between the structures because the closedform is expected to open on microtiter plates. An unexpected result was thepresence of immune complexes of β2GPI-Aβ2GPIA found in the serum of one of the patients. In theory an ELISA based on theopen form of β2GPI would provide more reliable diagnoses and furtherresearch is needed in this area.  

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  • 372.
    Wahlin, Linda
    Linnaeus University, Faculty of Health and Life Sciences, Department of Chemistry and Biomedical Sciences.
    Utveckling och analys av isglass sötad med fruktjuice2018Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Syftet med studien var att undersöka om det är möjligt att ta fram en isglass baserad på enbart fruktjuice och som uppfyller ställda krav på textur samt smak. Sockret i isglassen har en central påverkan på smak, fryspunkt och smälthastighet samt utgör den största delen torrsubstans. I studien har en serie mätningar genomförts där smältkaraktär, smälthastighet och fryspunkt på tre isglassar med olika procentuell andel druvjuice (14 %, 19 % och 24 %) samt en referensglass, som hade ett sockerinnehåll som motsvarade 22 g socker/100 g produkt, har undersökts. Resultatet från den genomförda studien visade att samtliga isglassar med fruktjuice klarade ställda krav på smältning. Fryspunkten skiljde sig som förväntat jämfört med referensglassen. Analys av smälthastigheter för de studerade glassammansättningarna visade på ett icke-linjärt samband mellan andel fruktjuice och maximal smälthastighet. Erhållna data från dessa mätningar var dock begränsad i antalet mätningar som genomfördes samt att temperaturen inte var konstant under försöken. Det sensoriska testet resulterade i att 89 % (8 av 9 deltagare) föredrog isglassen med 24 % druvjuice. Sammanfattningsvis indikerar resultaten i studien på att fruktjuicer är en mer komplex blandning jämfört med en sockerlösning samt att fler faktorer påverkar smälthastigheten än enbart den procentuella halten druvjuice. För framtida studier skulle ett matematiskt samband eventuellt kunna tas fram för procentuell andel druvjuice och smälthastighet, där även fler styrande faktorer tas med i beräkningen, som kan användas till att förutse vilka smältegenskaper ett givet recept skulle erhålla och på så sett kunna effektivisera receptframställning.

  • 373. Wang, Conan
    et al.
    Hu, Shu-Hong
    Martin, Jennifer
    Sjögren, Tove
    Hajdu, Janos
    Bohlin, Lars
    Claeson, Per
    Göransson, Ulf
    Rosengren, K. Johan
    University of Kalmar, School of Pure and Applied Natural Sciences.
    Tang, Jun
    Tan, Nin-hua
    Craik, David J.
    Combined X-ray and NMR analysis of the stability of the cyclotide cystine knot fold that underpins its insecticidal activity and potential use as a drug scaffold2009In: Journal of Biological Chemistry, ISSN 0021-9258, E-ISSN 1083-351X, Vol. 284, no 16, p. 10672-10683Article in journal (Refereed)
    Abstract [en]

    Cyclotides are a family of plant defense proteins that are highly resistant to adverse chemical, thermal, and enzymatic treatment. Here, we present the first crystal structure of a cyclotide, varv F, from the European field pansy, Viola arvensis, determined at a resolution of 1.8 angstrom. The solution state NMR structure was also determined and, combined with measurements of biophysical parameters for several cyclotides, provided an insight into the structural features that account for the remarkable stability of the cyclotide family. The x-ray data confirm the cystine knot topology and the circular backbone, and delineate a conserved network of hydrogen bonds that contribute to the stability of the cyclotide fold. The structural role of a highly conserved Glu residue that has been shown to regulate cyclotide function was also determined, verifying its involvement in a stabilizing hydrogen bond network. We also demonstrate that varv F binds to dodecylphosphocholine micelles, defining the binding orientation and showing that its structure remains unchanged upon binding, further demonstrating that the cyclotide fold is rigid. This study provides a biological insight into the mechanism by which cyclotides maintain their native activity in the unfavorable environment of predator insect guts. It also provides a structural basis for explaining how a cluster of residues important for bioactivity may be involved in self-association interactions in membranes. As well as being important for their bioactivity, the structural rigidity of cyclotides makes them very suitable as a stable template for peptide-based drug design.

  • 374.
    Westerhult, David
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Weak Affinity Chromatography: Evaluation of Different Silica Supports for Protein Immobilizationand Effect of Mobile Phases Regarding Retentionand Non-specific Binding2012Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Fragment based lead discovery (FBLD), where libraries of small fragments are screened andlater on developed to lead compounds, is an alternative to the classical drug discovery methods such as high trough-put screening. Weak affinity chromatography (WAC) is a new promising approach to the screening process of FBLD. WAC is performed by injections of fragments onto a high performance liquid chromatography (HPLC) column in which a protein is immobilized to a silica support. The retention of the injected fragments is correlated to the binding affinity of the fragments towards the immobilized protein. Immobilization capacity of three different silica materials with varying pore size (Kromasil240 Å, Nucleosil 1000 Å and Kromasil 300 Å) was evaluated by immobilization of trypsin. Retention of benzamidines on the trypsin columns was evaluated with different mobile phases. Contribution of non-specific binding in the interaction between the 4-aminobenzamidine and thrombin was estimated by frontal chromatography on a capillary columnusing PBS and PBS/acetonitrile as mobile phases. This study showed that the Kromasil 300 Å had a superior immobilization capacity of trypsin compared to the Kromasil 240 Å andthe Nucleosil 1000 Å (100 mg compared to 87.4 mg and 15.1 mg trypsin/g silica, respectively). However, the Nucleosil 1000 Å might be a more suitable support for the immobilization of larger proteins. Adding 5 % methanol or acetonitrile to the mobile phase resulted in a significant (p < 0.05) decreased retention of benzamidine fragments on the trypsin 240 Å column. Non-specific binding between thrombin and 4-ABA was not statistically significantly altered when 5 % acetonitrile was added to the mobile phase.

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  • 375.
    Wijma, Hein J
    et al.
    University of Groningen, The Netherlands.
    Floor, Robert J
    University of Groningen, The Netherlands.
    Bjelic, Sinisa
    University of Washington, USA.
    Marrink, Siewert J
    University of Groningen, The Netherlands.
    Baker, David
    University of Washington, USA.
    Janssen, Dick B
    University of Groningen, The Netherlands.
    Enantioselective enzymes by computational design and in silico screening2015In: Angewandte Chemie International Edition, ISSN 1433-7851, E-ISSN 1521-3773, Vol. 54, no 12, p. 3726-3730Article in journal (Refereed)
    Abstract [en]

    Computational enzyme design holds great promise for providing new biocatalysts for synthetic chemistry. A strategy to design small mutant libraries of complementary enantioselective epoxide hydrolase variants for the production of highly enantioenriched (S,S)-diols and (R,R)-diols is developed. Key features of this strategy (CASCO, catalytic selectivity by computational design) are the design of mutations that favor binding of the substrate in a predefined orientation, the introduction of steric hindrance to prevent unwanted substrate binding modes, and ranking of designs by high-throughput molecular dynamics simulations. Using this strategy we obtained highly stereoselective mutants of limonene epoxide hydrolase after experimental screening of only 37 variants. The results indicate that computational methods can replace a substantial amount of laboratory work when developing enantioselective enzymes.

  • 376.
    Wiklander, Jesper G.
    et al.
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Karlsson, Björn C. G.
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Aastrup, Teodor
    Attana AB, Stockholm.
    Nicholls, Ian A.
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    A synthetic polymer with avidin-like binding properties2010Conference paper (Refereed)
    Abstract [en]

    A series of streptavidin mimicking molecularly imprinted polymers has been developed and evaluated for their biotin binding characteristics. A combination of molecular dynamics and NMR spectroscopy was used to examine potential polymer systems, in particular with the functional monomers methacrylic acid and 2-acrylamidopyridine. Synthesis of co-polymers of ethylene dimethacrylate and one or both of these functional monomers was performed. A combination of radioligand binding studies and surface area analyses (BET, SEM) demonstrated the presence of selectivity in polymers prepared using methacrylic acid as functional monomer. This correlated well with the molecular dynamics studies, showing the power of this methodology as a prognostic tool for predicting the behaviour of molecularly imprinted polymers.

  • 377.
    Wiklander, Jesper G.
    et al.
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Karlsson, Björn C. G.
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Aastrup, Teodor
    Nicholls, Ian A.
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Towards a synthetic avidin mimic2011In: Analytical and Bioanalytical Chemistry, ISSN 1618-2642, E-ISSN 1618-2650, Vol. 400, no 5, p. 1397-1404Article in journal (Refereed)
    Abstract [en]

    A series of streptavidin-mimicking molecularly imprinted polymers has been developed and evaluated for their biotin binding characteristics. A combination of molecular dynamics and NMR spectroscopy was used to examine potential polymer systems, in particular with the functional monomers methacrylic acid and 2-acrylamidopyridine. The synthesis of copolymers of ethylene dimethacrylate and one or both of these functional monomers was performed. A combination of radioligand binding studies and surface area analyses demonstrated the presence of selectivity in polymers prepared using methacrylic acid as the functional monomer. This was predicted by the molecular dynamics studies showing the power of this methodology as a prognostic tool for predicting the behavior of molecularly imprinted polymers.

  • 378. Witzgall, P
    et al.
    Trematerra, P
    Liblikas, Ilme
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Bengtsson, M
    Unelius, C. Rikard
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Pheromone communication channels in tortricid moths: lower specificity of alcohol vs. acetate geometric isomer blends2010In: Bulletin of entomological research, ISSN 0007-4853, E-ISSN 1475-2670, Vol. 100, no 2, p. 225-230Article in journal (Refereed)
    Abstract [en]

    Discrimination of conspecific and heterospecific signals is a key element in the evolution of specific mate recognition systems. Lepidopteran pheromone signals are typically composed of several compounds that synergize attraction of conspecific and inhibit attraction of heterospecific males. Blends convey specificity, but not their single components, that are typically shared by several species. Many sex pheromones are blends of geometric or positional isomers of straight-chain acetates, while species-specific blends of analogous alcohols have not been described. We have, therefore, studied the attraction of tortricid moths to the geometric isomers (E,E)-, (E,Z)-, (Z,E)- and (Z,Z)-8,10-dodecadien-1-ol. Only one species responding to these alcohols seemed to be attracted to a blend of two isomers, while most species are attracted to only one alcohol isomer. Lack of a pronounced synergist or antagonist effect of the other geometric isomers explains the lack of specific attraction to isomer blends and reduces accordingly the number of specific communication signals composed of these alcohols. In comparison, many more species respond to the analogous (E,E)-, (E,Z)-, (Z,E)- and (Z,Z)-8,10-dodecadienyl acetates and their binary blends. The acetate isomers all play a behavioural role, either as attractants, attraction synergists or antagonists, and thus promote specific communication with acetate blends. Male moths seem to discriminate the acetate isomers with greater precision than the analogous alcohols. It is proposed that discrimination is facilitated by steric differences between the four acetate isomers, as compared to the more uniform steric properties of the alcohols.

  • 379.
    Wällstedt, Elin
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Development and preliminary evaluation of novel materials for selective detection of oseltamivir in waste water2019Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This project aims to investigate whether it is possible to detect consentrations down to 0,3 µg/L of oseltamirir in waste water by Quartz Crystal Microbalance. The risks linked to this contaminant could be not only environmental, scientists have found that infuence recistence can propagate due to contaminats of this kind. Cases similar to the bird- and swine-flu could occure if the drug spreads through animals and mutate.

     

    Four systems of different character was synthesised. As a result it was found that MAA functional monomer systems probably was interfering with charges within it’s own nanowires.

    Reference systems could not detect 0,01 mg/mL and HEMA polymer surfaces was the only reliable system, pH of 5,1. Lowest limit of detection (LOD) was found in Molecular Imprinted Polymer nanowires (MIP Nw) at 0,01 mg/mL and could be scaled down to 0,1 mg/L with increased loop size (injection at 10x that of 0,01 mg/mL at about 500 µL and a halved flow rate.)

     

    An alternative could be nano structuring such as ”polystyrene balls” that possibly could be able to achieve surfaces with even more binding sites needed to detect the lowest limit at 0,3 µg/L. 

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  • 380.
    Wójcik, Natalia A.
    et al.
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology. Gdańsk University of Technology, Poland.
    Ali, Sharafat
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Möncke, Doris
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology. Alfred University, USA;National Hellenic Research Foundation, Greece.
    Kamitsos, Efstratios
    National Hellenic Research Foundation, Greece.
    Segawa, Hiroyo
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology. National Institute for Materials Science, Japan.
    Eriksson, Mirva
    Stockholm University, Sweden.
    Jonson, Bo
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    The influence of Be addition on the structure and thermal properties of alkali-silicate glasses2019In: Journal of Non-Crystalline Solids, ISSN 0022-3093, E-ISSN 1873-4812, Vol. 521, article id 119532Article in journal (Refereed)
    Abstract [en]

    Be-Na-(Li)-Si oxide glasses containing up to 15 mol% of BeO were prepared. Their structure was characterized by X-ray powder diffraction and Raman as well as infrared spectroscopic techniques, while their chemical compositions were examined by Inductively Coupled Plasma Optical Emission Spectrometry. All materials were found to be amorphous and contain Al contaminations from minor dissolution of the alumina crucibles. The results of Raman and IR spectroscopies showed that BeO addition to Na-(Li)-Si glass systems resulted in the formation of [BeO4/2]2− tetrahedra which are inserted into the silicate glass network, demonstrating the intermediate glass-forming role of BeO. In parallel, the effective destruction of Si-O-Si bridges was observed by vibrational spectroscopy. The glass transition temperature was studied by Differential Thermal Analysis and found to range from about 431 °C to 551 °C. A significant increase in Tg by 70 °C was found as SiO2 was substituted by up to 15 mol% BeO.

  • 381.
    Xie, Sheng
    et al.
    KTH Royal Instute of Technology, Sweden;Hunan Univ, Peoples Republic of China.
    Manuguri, Sesha
    KTH Royal Instute of Technology, Sweden.
    Ramström, Olof
    Linnaeus University, Faculty of Health and Life Sciences, Department of Chemistry and Biomedical Sciences. KTH Royal Instute of Technology, Sweden;Univ Massachusetts, USA.
    Yan, Mingdi
    KTH Royal Instute of Technology, Sweden;Univ Massachusetts, USA.
    Impact of Hydrogen Bonding on the Fluorescence of N-Amidinated Fluoroquinolones2019In: Chemistry - An Asian Journal, ISSN 1861-4728, E-ISSN 1861-471X, Vol. 14, no 6, p. 910-916Article in journal (Refereed)
    Abstract [en]

    The fluorescence properties of AIE-active N-amidinated fluoroquinolones, efficiently obtained by a perfluoroaryl azide-aldehyde-amine reaction, have been studied. The fluorophores were discovered to elicit a highly sensitive fluorescence quenching response towards guest molecules with hydrogen-bond-donating ability. This effect was evaluated in a range of protic/aprotic solvents with different H-bonding capabilities, and also in aqueous media. The influence of acid/base was furthermore addressed. The hydrogen-bonding interactions were studied by IR, NMR, UV/Vis and time-resolved fluorescence decay, revealing their roles in quenching of the fluorescence emission. Due to the pronounced quenching property of water, the N-amidinated fluoroquinolones could be utilized as fluorescent probes for quantifying trace amount of water in organic solvents.

  • 382.
    Xie, Sheng
    et al.
    Hunan Univ, China;KTH Royal instute of technology, Sweden.
    Proietti, Giampiero
    KTH Royal instute of technology, Sweden.
    Ramström, Olof
    Linnaeus University, Faculty of Health and Life Sciences, Department of Chemistry and Biomedical Sciences. KTH Royal instute of technology, Sweden;Univ Massachusetts Lowell, USA.
    Yan, Mingdi
    Univ Massachusetts Lowell, USA.
    Photoactivatable Fluorogens by Intramolecular C-H Insertion of Perfluoroaryl Azide2019In: Journal of Organic Chemistry, ISSN 0022-3263, E-ISSN 1520-6904, Vol. 84, no 22, p. 14520-14528Article in journal (Refereed)
    Abstract [en]

    Molecules, capable of fluorescence turn-on by light, are highly sought-after in spatio-temporal labeling, surface patterning, monitoring cellular and molecular events, and high-resolution fluorescence imaging. In this work, we report a fluorescence turn-on system based on photoinitiated intramolecular C-H insertion of azide into the neighboring aromatic ring. The azide-masked fluorogens were efficiently synthesized via a cascade nucleophilic aromatic substitution of perfluoroaryl azides with carbazoles. The scaffold also allows for derivatization with biological ligands, as exemplified with D-mannose in this study. This photoinitiated intramolecular transformation led to high yields, high photo-conversion efficiency, and well-separated wavelengths for photoactivation and fluorescence excitation. The mannose-derivatized structure enabled spatio-temporal activation and showed high contrast and signal amplification. Live cell imaging suggested that the mannose-tagged fluorogen was transported to the lysosomes.

  • 383.
    Xie, Sheng
    et al.
    KTH Royal Instute of Technology;Hunan Univ, Peoples Republic of China.
    Zhou, Juan
    KTH Royal Instute of Technology;Jiangnan Univ, Peoples Republic of China.
    Chen, Xuan
    Univ Massachusetts Lowell, USA.
    Kong, Na
    KTH Royal Instute of Technology.
    Fan, Yanmiao
    KTH Royal Instute of Technology.
    Zhang, Yang
    KTH Royal Instute of Technology.
    Hammer, Gerry
    Univ Washington, USA.
    Castner, David G.
    Univ Washington, USA.
    Ramström, Olof
    Linnaeus University, Faculty of Health and Life Sciences, Department of Chemistry and Biomedical Sciences. KTH Royal Instute of Technology;Univ Massachusetts Lowell, USA.
    Yan, Mingdi
    KTH Royal Instute of Technology;Univ Massachusetts Lowell, USA.
    A versatile catalyst-free perfluoroaryl azide-aldehyde-amine conjugation reaction2019In: Materials Chemistry Frontiers, E-ISSN 2052-1537, Vol. 3, no 2, p. 251-256Article in journal (Refereed)
    Abstract [en]

    In a tri-component reaction, an electrophilically-activated perfluoroaryl azide, an enolizable aldehyde and an amine react readily at room temperature without any catalysts in solvents including aqueous conditions to yield a stable amidine conjugate. The versatility of this reaction is demonstrated in the conjugation of an amino acid without prior protection of the carboxyl group, and in the synthesis of antibiotic-nanoparticle conjugates.

  • 384.
    Yu, Qian
    et al.
    University of Mississippi, USA;China Pharmaceut University, Peoples Republic of China.
    Ravu, Ranga Rao
    University of Mississippi, USA.
    Xu, Qiong-Ming
    University of Mississippi, USA.
    Ganji, Suresh
    University of Mississippi, USA.
    Jacob, Melissa R.
    University of Mississippi, USA.
    Khan, Shabana I.
    University of Mississippi, USA.
    Yu, Bo-Yang
    China Pharmaceut University, Peoples Republic of China.
    Li, Xing-Cong
    University of Mississippi, USA.
    Antibacterial Prenylated Acylphloroglucinols from Psorothamnus fremontii2015In: Journal of natural products (Print), ISSN 0163-3864, E-ISSN 1520-6025, Vol. 78, no 11, p. 2748-2753Article in journal (Refereed)
    Abstract [en]

    Psorothatins A-C (1-3), three antibacterial prenylated acylphloroglucinol derivatives, were isolated from the native American plant Psorothamnus fremontii. They feature an unusual alpha,beta-epoxyketone functionality and a beta-hydroxy-alpha,beta-unsaturated ketone structural moiety. The latter forms a pseudo-six-membered heterocyclic ring due to strong intramolecular hydrogen bonding, as indicated by the long-range proton-carbon correlations in the NMR experiments. Psorothatin C (3) was the most active compound against methicillin-resistant Staphylococcus aureus and vancomycin-resistant Enterococcus faecium, with IC50 values in the range 1.4-8.8 mu g/mL. The first total synthesis of 3 described herein permits future access to structural analogues with potentially improved antibacterial activities.

  • 385.
    Zhang, Yan
    et al.
    Jiangnan Univ, China.
    Barboiu, Mihail
    Univ Montpellier, France.
    Ramström, Olof
    Linnaeus University, Faculty of Health and Life Sciences, Department of Chemistry and Biomedical Sciences. Univ Massachusetts, USA.
    Chen, Jinghua
    Jiangnan Univ, China.
    Surface-Directed Selection of Dynamic Constitutional Frameworks as an Optimized Microenvironment for Controlled Enzyme Activation2020In: ACS Catalysis, ISSN 2155-5435, E-ISSN 2155-5435, Vol. 10, no 2, p. 1423-1427Article in journal (Refereed)
    Abstract [en]

    Dynamic constitutional frameworks composed of cross-linked networks of imine-exchanging components have been generated and applied to the establishment of optimal microenvironments for carbonic anhydrase (CA) in aqueous solution., In response to the dynamic recomposition process, the enzyme showed distinct differential preferences for interchanging and incorporation of the amine functionalities, which were furthermore in good correlation with their inverse activation effects of CA. The results demonstrated surface-directed selection of the enzyme environment, where amines with lower enzyme-directed incorporation ratio possess higher activation effects, leading to a strategy of self-optimization of the enzyme microenvironment for better catalytic performances.

  • 386.
    Zhang, Yan
    et al.
    Jiangnan Univ, China.
    Qi, Yunchuan
    Univ Massachusetts, USA.
    Ulrich, Sebastien
    Univ Montpellier, France.
    Barboiu, Mihail
    Univ Montpellier, France.
    Ramström, Olof
    Linnaeus University, Faculty of Health and Life Sciences, Department of Chemistry and Biomedical Sciences. Univ Massachusetts, USA.
    Dynamic covalent polymers for biomedical applications2020In: Materials Chemistry Frontiers, E-ISSN 2052-1537, Vol. 4, no 2, p. 489-506Article, review/survey (Refereed)
    Abstract [en]

    The rapid development of supramolecular polymer chemistry and constitutional dynamic chemistry over the last decades has made tremendous impact on the emergence of dynamic covalent polymers. These materials are formed through reversible covalent bonds, endowing them with adaptive and responsive features that have resulted in high interest throughout the community. Owing to their intriguing properties, such as self-healing, shape-memory effects, recyclability, degradability, stimuli-responsiveness, etc., the materials have found multiple uses in a wide range of areas. Of special interest is their increasing use for biomedical applications, and many examples have been demonstrated in recent years. These materials have thus been used for the recognition and sensing of biologically active compounds, for the modulation of enzyme activity, for gene delivery, and as materials for cell culture, delivery, and wound-dressing. In this review, some of these endeavors are discussed, highlighting the many advantages and unique properties of dynamic covalent polymers for use in biology and biomedicine.

  • 387.
    Zhang, Yan
    et al.
    Jiangnan Univ, China.
    Zhang, Yang
    Hunan Univ, China.
    Ramström, Olof
    Linnaeus University, Faculty of Health and Life Sciences, Department of Chemistry and Biomedical Sciences. Univ Massachusetts, USA.
    Dynamic covalent kinetic resolution2020In: Catalysis reviews. Science and engineering, ISSN 0161-4940, E-ISSN 1520-5703, Vol. 62, no 1, p. 66-95Article in journal (Refereed)
    Abstract [en]

    Implemented with the highly efficient concept of Dynamic Kinetic Resolution (DKR), dynamic covalent chemistry can be a useful strategy for the synthesis of enantioenriched compounds. This gives rise to dynamic covalent kinetic resolution (DCKR), a subset of DKR that over the last decades has emerged as increasingly fruitful, with many applications in asymmetric synthesis and catalysis. All DKR protocols are composed of two important parts: substrate racemization and asymmetric transformation, which can lead to yields of >50% with good enantiomeric excesses (ee) of the products. In DCKR systems, by utilizing reversible covalent reactions as the racemization strategy, the substrate enantiomers can be easily interconverted without the presence of any racemase or transition metal catalyst. Enzymes or other chiral catalysts can then be adopted for the resolution step, leading to products with high enantiopurities. This tutorial review focuses on the development of DCKR systems, based on different reversible reactions, and their applications in asymmetric synthesis.

  • 388.
    Zhao, Shangqing
    Linnaeus University, Faculty of Health and Life Sciences, Department of Chemistry and Biomedical Sciences.
    Coumarin-based molecular probes: exploring the spectroscopic properties of complex mixtures and applications in colloid chemistry2018Independent thesis Advanced level (degree of Master (One Year)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Warfarin is a well-known anticoagulant drug that is used to prevent cardiovascular disease and blood coagulation such as thrombosis. In this study, the main aim was to investigate the photo physical characteristics of warfarin in the different molecular environments provided by sodium dodecyl sulfate (SDS) micelles by using ultraviolet absorption and fluorescence emission spectroscopic techniques. Warfarin and a structural analogue not existing in solution as a cyclic hemiketal, phenprocoumon, were mixed with different concentrations of SDS and spectral changes for these warfarin and phenprocoumon were recorded. Interestingly, results demonstrated, based on an evident increase in the absorption intensity at 273 nm and an evident blue shift in the fluorescence emission spectrum after the addition of an increasing concentration of SDS, that primarily the cyclic hemiketal isomer of warfarin was found to be solvated by SDS micelles at an apparent recorded critical micelle concentration of ~8mM.  Altogether these observations suggest that warfarin may be used as a molecular probe to explore the polarities of complex colloidal mixtures. Moreover, the possibility of using micelles for controlling the isomeric state of warfarin is interesting and can potentially be used for better controlling dosage of warfarin thereby reducing side effects.

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  • 389.
    Zhao, Tao
    et al.
    Linnaeus University, Faculty of Health and Life Sciences, Department of Chemistry and Biomedical Sciences. KTH Royal Instute of Technology, Sweden;Örebro University, Sweden.
    Ganji, Suresh
    Linnaeus University, Faculty of Health and Life Sciences, Department of Chemistry and Biomedical Sciences.
    Bohman, Björn
    Linnaeus University, Faculty of Health and Life Sciences, Department of Chemistry and Biomedical Sciences. University of Western Australia, Australia.
    Weinstein, Philip
    University of Adelaide, Australia.
    Krokene, Paal
    Norwegian Institute of Bioeconomy Research, Norway.
    Borg-Karlsson, Anna-Karin
    KTH Royal Instute of Technology, Sweden.
    Unelius, C. Rikard
    Linnaeus University, Faculty of Health and Life Sciences, Department of Chemistry and Biomedical Sciences.
    Convergent evolution of semiochemicals across Kingdoms: bark beetles and their fungal symbionts2019In: The ISME Journal, ISSN 1751-7362, E-ISSN 1751-7370, Vol. 13, no 6, p. 1535-1545Article in journal (Refereed)
    Abstract [en]

    Convergent evolution of semiochemical use in organisms from different Kingdoms is a rarely described phenomenon. Treekilling bark beetles vector numerous symbiotic blue-stain fungi that help the beetles colonize healthy trees. Here we show for the first time that some of these fungi are able to biosynthesize bicyclic ketals that are pheromones and other semiochemicals of bark beetles. Volatile emissions of five common bark beetle symbionts were investigated by gas chromatography-mass spectrometry. When grown on fresh Norway spruce bark the fungi emitted three well-known bark beetle aggregation pheromones and semiochemicals (exo-brevicomin, endo-brevicomin and trans-conophthorin) and two structurally related semiochemical candidates (exo-1,3-dimethyl-2,9-dioxabicyclo[3.3.1]nonane and endo-1,3-dimethyl-2,9-dioxabicyclo[3.3.1] nonane) that elicited electroantennogram responses in the spruce bark beetle Ips typographus. When grown on malt agar with 13C D-Glucose, the fungus Grosmannia europhioides incorporated 13C into exo-brevicomin and trans-conophthorin. The enantiomeric compositions of the fungus-produced ketals closely matched those previously reported from bark beetles. The production of structurally complex bark beetle pheromones by symbiotic fungi indicates cross-kingdom convergent evolution of signal use in this system. This signaling is susceptible to disruption, providing potential new targets for pest control in conifer forests and plantations.

  • 390.
    Åman, Sandra
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Stabila bakfyllningar2011Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Fyllning i kakor (s.k. bakfyllning) kan under bakning och särskilt under lagring ge negativa effekter så som migrering av fyllning och olja ut i kakdegen. Valet av fettsystem i fyllningen och dess smältpunkt är av stor betydelse för att erhålla önskvärd konsistens och textur. Syftet med examensarbetet var att minimera dessa negativa effekter samt att kartlägga faktorer som påverkar detta. Tidigare bakförsök vid AarhusKarlshamn har visat att fyllningens partikelstorlek påverkar migreringen, då migreringen tycks öka med ökande partikelstorlek. Examensarbetet innefattade provbakningar, fysikaliska analyser och sensoriska test. Baktemperatur och avsvalningshastigheten varierades. Kakdegens socker varierades med strö- och florsocker för att ge olika porositet. Fyllningarna baserades på tre olika fettsystem; A, B och B:C. Fettsystem B gav dock fyllningen för lös konsistens och uteslöts senare ur studien. Fyllningarnas normala (N) partikelstorlek var 50 μm och fyllning baserad på A valsades för att reducera partikelstorleken till 10, 20 respektive 40 μm, vilka namngavs A(10), A(20) respektive A(40). Oljemigrering studerades efter 3 dagar och 2,5 veckor genom sensorisk utvärdering och texturanalys. Differential scanning calorimetry och reologi användes för att studera fyllningens fysikaliska egenskaper. Ingen signifikant skillnad i textur kunde påvisas med olika socker i kakdegen eller med de olika använda baktemperaturerna (160 resp. 190 °C). Den sensoriska och visuella utvärderingen visade att för kakor med fyllning A(N) och A(40) gav mest oljemigrering. Detta styrktes med resultat från texturanalysen. Smältpunkten för fyllning baserad på A bestämdes till ~48,4 °C och fyllning baserad på B:C till 60,6 °C. Partikelstorlek visades således ha inverkan på oljemigreringen och en partikelstorlek ≤ 20 μm är nödvändig för att fyllningen ska vara stabil, dvs. ingen migrering av fyllning och olja.

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    Stabila bakfyllningar
  • 391.
    Åqvist, Johan
    et al.
    Uppsala University.
    Wennerström, Petra
    Uppsala University.
    Nervall, Martin
    Uppsala University.
    Bjelic, Sinisa
    Uppsala University.
    Brandsdal, Bjørn O.
    Uppsala University.
    Molecular dynamics simulations of water and biomolecules wit a Monte Carlo constant pressure algorithm2004In: Chemical Physics Letters, ISSN 0009-2614, E-ISSN 1873-4448, Vol. 384, no 4-6, p. 288-294Article in journal (Refereed)
    Abstract [en]

    A mixed molecular dynamics/Monte Carlo (MD/MC) algorithm for constant pressure simulations of arbitrary molecular systems is examined. Calculations are reported at ambient and high pressures both for liquid water systems and for a chemical reaction step in a solvated enzyme utilizing empirical valence bond potentials. The present method reproduces earlier reported results well and is computationally efficient since it does not require the virial to be evaluated at each MD step. It is also found that the effects of introducing MC volume steps on the dynamics of the system are negligible provided that the volume step sizes and updating frequencies are appropriately chosen.

  • 392.
    Öberg, Tomas
    European Chemicals Agency (ECHA), Helsinki, Finland.
    Substitution of chemicals based on assessment of hazard, risk and impact2014In: Journal of Risk Research, ISSN 1366-9877, E-ISSN 1466-4461, Vol. 17, no 5, p. 565-568Article in journal (Other academic)
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