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  • 1.
    Ahlqvist, Josefin
    et al.
    Lund University, Lund, Sweden .
    Kumar, Ashok
    Lund University, Lund, Sweden .
    Sundström, Heléne
    Royal Institute of Technology, Stockholm, Sweden.
    Ledung, Erika
    Mälardalen University, Department of Biology and Chemical Engineering.
    Hörnsten, E. Gunnar
    SIK, Swedish Institute for Food and Biotechnology, Sweden.
    Enfors, Sven-Olof
    Mälardalen University, Department of Biology and Chemical Engineering.
    Mattiasson, Bo
    Lund University, Lund, Sweden .
    Affinity binding of inclusion bodies on supermacroporous monolithic cryogels using labeling with specific antibodies.2006In: Journal of Biotechnology, ISSN 0168-1656, Vol. 122, no 2, p. 216-225Article in journal (Refereed)
    Abstract [en]

    A new chromatographic method based on affinity supermacroporous monolithic cryogels is developed for binding and analyzing inclusion bodies during fermentation. The work demonstrated that it is possible to bind specific IgG and IgY antibodies to the 15 and 17 amino acids at the terminus ends of a 33kDa target protein aggregated as inclusion bodies. The antibody treated inclusion bodies from lysed fermentation broth can be specifically retained in protein A and pseudo-biospecific ligand sulfamethazine modified supermacroporous cryogels. The degree of binding of IgG and IgY treated inclusion bodies to the Protein A and sulfamethazine gels are investigated, as well as the influence of pH on the sulfamethazine ligand. Optimum binding of 78 and 72% was observed on both protein A and sulfamethazine modified cryogel columns, respectively, using IgG labeling of the inclusion bodies. The antibody treated inclusion bodies pass through unretained in the sulfamethazine supermacroporous gel at pH that does not favour the binding between the ligand on the gel and the antibodies on the surface of inclusion bodies. Also the unlabeled inclusion bodies went through the gel unretained, showing no non-specific binding or trapping within the gel. These findings may very well be the foundation for the building of a powerful analytical tool during fermentation of inclusion bodies as well as a convenient way to purify them from fermentation broth. These results also support our earlier findings [Kumar, A., Plieva, F.M., Galaev, I.Yu., Mattiasson, B., 2003. Affinity fractionation of lymphocytes using a monolithic cyogel. J. Immunol. Methods 283, 185-194] with mammalian cells that were surface labeled with specific antibodies and recognized on protein A supermacroporous gels. A general binding and separation system can be established on antibody binding cryogel affinity matrices.

  • 2.
    Andersson, Emilia
    et al.
    Mälardalen University, Department of Biology and Chemical Engineering.
    Danielsson, Moa
    Mälardalen University, Department of Biology and Chemical Engineering.
    Naturskolan- en metod till lärande?: Outdoor teaching - A method for learning?2008Independent thesis Basic level (professional degree), 10 points / 15 hpStudent thesis
    Abstract [en]

    The purpose of this essay is to find an answer to whether the methodology used by the Naturskolan conduces to learning and also if the Naturskolan, as a method of its own, leads to an increased interest in natural science for the pupils participating in the classes at the Naturskolan.

    The method which has been used to reach the results of the study is a quantitative opinion poll. The results reached through the study has been compared to previous research in the subject. Deeper studies were made to examine however the interest of the pupils was influenced by their visit at the Naturskolan.

    The results of the study show an increase of interest in natural science after visiting the Naturskolan. It also shows that the teachers’ interest in natural science and outdoor pedagogy has increased by the visit at the Naturskolan.

    Through this study we came to the conclusion that the Naturskolan is a good method to learning.

  • 3.
    Angus-Dunne, Sarah
    et al.
    Mälardalen University, Department of Biology and Chemical Engineering.
    Burns, Robert C.
    Craig, Donald C.
    Lawrance, Geoffrey A.
    Synthesis and Crystal Structure of the Palladium(IV) Polyoxomolybdate, K0 75Na3 75[PdMo6O24H3 5]center dot 17H(2)O2010In: Zeitschrift für Anorganische und Allgemeines Chemie, ISSN 0044-2313, E-ISSN 1521-3749, Vol. 636, no 5, p. 727-734Article in journal (Refereed)
    Abstract [en]

    The first example of a heteropolyoxomolybdate containing palladium(IV) was isolated and characterized by X ray crystallography The palladium(IV) hexamolybdate, K0 75Na3 75[PdMo6O24H3 (5)] 17H(2)O, was isolated from an aqueous solution at pH 4 5 in the space group P (1) over bar a 10 790(2) b 12 244(3), c 14 086(3) angstrom, alpha 113 77(1), beta 90 41(1) gamma 107 86(1)degrees and the structure was determined using X ray diffraction methods refining to a residual of 0 0301 for 5334 reflections A formal [PdMo6O24H3](5-) subunit exhibits the basic Anderson structure with two [PdMo6O24H3](5-) cluster anions in the structure bridged by a hydrogen atom (formally an H+) situated on a center of symmetry to give a [Pd2Mo12O48H7](9-) dimeric anion The palladium(IV) atom occupies a slightly distorted octahedral environment with Pd-O distances ranging from 1 968 to 2 009 angstrom.

  • 4.
    Angus-Dunne, Sarah J.
    et al.
    Mälardalen University, Department of Biology and Chemical Engineering.
    Dunne, Simon J.
    Mälardalen University, Department of Biology and Chemical Engineering.
    The Dissociation Constants of Diprotonated Chalcogenobispyridines: Transmission of Electronic Effects Across Chalcogen Bridges2011In: Journal of Heterocyclic Chemistry, ISSN 0022-152X, E-ISSN 1943-5193, Vol. 48, no 4, p. 868-871Article in journal (Refereed)
    Abstract [en]

    The dissociation constants of the diprotonated chalcogenobispyridines have been determined using potentiometric titrations to establish a method for the measurement of the ability of a bridging ligand to relay electronic effects. The relationship between pK(a) and structure of the chalcogenobispyridines results from a balance between inductive, mesomeric, and steric effects. Delocalization of cationic charge onto the bridgehead increases the apparent electronegativity of the bridging atom, thereby relaying a strong base-weakening effect to the site of first deprotonation. Such delocalization was found to be a function of both the substitution site (4-X > 2-X >> 3-X) and orbital overlap requirements (S > O approximate to Se > Te).

  • 5.
    Bergenheim, Veronica
    Mälardalen University, Department of Biology and Chemical Engineering.
    Effects of nicotine on GABAA subunit expression in the rat brain2007Student thesis
    Abstract [en]

    Smoking is a worldwide problem and it is the second major cause of death. People often try to quit, but few succeed mainly because of withdrawal symptoms such as irritability, anxiety, increased appetite, hyperventilation and difficulty concentrating.

    The overall aim of this project was to study neurochemical changes in the brain following sensitization to nicotine which could give more information about what causes an individual to go from using drugs to abusing the drugs. Therefore, we investigated messenger ribonucleic acid (mRNA) expression of several genes known to be involved in the mesolimbic dopamine pathway in the nucleus accumbens, caudate putamen, prefrontal cortex and medial prefrontal cortex using real-time polymerase chain reaction (real-time PCR).

    The results showed that in the nucleus accumbens, mRNA expression of gamma-aminobutyric acid (GABA) Aα1 subunit receptor and GABA transporter 3 (GAT-3) were significantly increased following nicotine administration, while in the caudate putamen no difference in expression was observed. In prefrontal cortex, the expression of adrenergic subunit receptor α2A was significantly increased following hexamethonium administration. In medial prefrontal cortex a significant decrease of expression of GAT-1 was shown following nicotine and hexamethonium administration, while a decrease of CART expression only was shown following nicotine administration.

    Overall, these changes in the GABA system may help to explain the mechanism of nicotine sensitization.

  • 6.
    Bergkvist, Magnus
    et al.
    Mälardalen University, Department of Biology and Chemical Engineering.
    Carlsson, J
    Uppsala University, Sweden.
    Karlsson, T
    Pharmacia and Upjohn Diagnostics, Sweden.
    Oscarsson, Sven
    Mälardalen University, Department of Biology and Chemical Engineering.
    TM-AFM Threshold Analysis of Macromolecular Orientation: A Study of the Orientation of IgG and IgE on Mica Surfaces.1998In: Journal of Colloid and Interface Science, ISSN 0021-9797, Vol. 206, no 2, p. 475-481Article in journal (Refereed)
    Abstract [en]

    Adsorption and orientation properties of two different types of immunoglobulin molecules on derivatized and native mica surfaces were investigated using TM-AFM. The analyses included height measurements at two different pH values and a new technique, presented here as threshold analysis, which displays the outer mantle shape of an adsorbed protein. A major difference in preferential orientation is observed upon comparing the adsorption of the two proteins onto the different surfaces. The characteristics of both the adsorbed immunoglobulin and the surface are important for any preferential orientation of the adsorbed protein.

  • 7.
    Bergkvist, Magnus
    et al.
    Mälardalen University, Department of Biology and Chemical Engineering. Uppsala University, Sweden.
    Carlsson, Jan
    Uppsala University, Sweden.
    Oscarsson, Sven
    Mälardalen University, Department of Biology and Chemical Engineering. Uppsala University, Sweden.
    Surface-dependent conformations of human plasma fibronectin adsorbed to silica, mica, and hydrophobic surfaces, studied with use of Atomic Force Microscopy2003In: Journal of biomedical materials research. Part A., ISSN 0021-9304, Vol. 64, no 2, p. 349-356Article in journal (Refereed)
    Abstract [en]

    Human plasma fibronectin (Fn) is a large flexible protein stabilized by intermolecular ionic interactions forming a compact structure. On altering solution conditions, the structure can revert to a more expanded state, thereby exposing previously hidden domains (e.g., cell-binding sites). Electron microscopy images of Fn air-sprayed onto mica surfaces show elongated protein structures, indicating a surface-induced structural change. This makes it interesting to investigate the influence of surface properties on the structure of adsorbed Fn. We have used intermittent-contact Atomic Force Microscopy to investigate the structure of Fn adsorbed onto mica, silica, and methylated silica surfaces. We observed that on silica surfaces, which is hydrophilic, most (70%) of the molecules had an elongated structure with partial intramolecular chain interactions, compare to molecules adsorbed on hydrophobic, methylated surfaces, where a compact structure predominated (70%). On mica surfaces, both compact and elongated protein structures were observed, with a slight preference for the elongated form (53%). Results show that surface physical properties influence the molecular structure of fibronectin on adsorption, which could provide useful information in understanding surface-induced in vivo responses.

  • 8.
    Berna, Nathalie
    et al.
    Mälardalen University, Department of Biology and Chemical Engineering.
    Berna, P
    Uppsala University, Sweden.
    Oscarsson, Sven
    Mälardalen University, Department of Biology and Chemical Engineering.
    Cosolvent-induced adsorption and desorption of serum proteins on an amphiphilic mercaptomethylene pyridine-derivatized agarose gel1996In: Arch Biochem Biophys, ISSN 0003-9861, Vol. 330, no 1, p. 188-192Article in journal (Refereed)
    Abstract [en]

    We studied the effects of the following cosolvents on the adsorption and desorption of serum proteins from an amphiphilic mercaptomethylene pyridine-derivatized agarose gel: glucose, sucrose, polyethylene glycol (PEG), 2-methyl-2,4-pentanediol (MFD), sorbitol, pentaerythritol, glycerol, and Na2SO4. The water-structuring salt 0.4 M Na2SO4 was the most potent promoter of protein adsorption, followed by 5 M sorbitol and, to a lesser extent, 0.2 M PEG 1000 and 2.25 M MPD. The other cosolvents (4 M glucose, 1.5 M sucrose, 0.3 M pentaerythritol, and 7.6 M glycerol) were unable to promote protein adsorption to the gel. Attempts to modulate the salt-promotion effect of Na2SO4 with different cosolvents demonstrated the occurrence of synergistic effects for pentaerythritol, sorbitol, and glucose and antagonistic effects for the other cosolvents. Sorbitol and glycerol were found to be the most interesting co-solvents studied, as the first promoted protein adsorption, whereas the other disrupted protein interaction. As a consequence of these novel findings we propose sorbitol and glycerol, both well-known protein stabilizers, as possible alternatives to water-structuring salts during the adsorption phase and to deleterious organic solvents during the desorption phase on amphiphilic gels.

  • 9.
    Berner, S.
    et al.
    Uppsala University, Sweden.
    Biela, S.
    Uppsala University, Sweden.
    Ledung, G.
    Mälardalen University, School of Sustainable Development of Society and Technology.
    Gogoll, A.
    Uppsala University, Sweden.
    Bäckvall, J.E.
    Stockholm University, Sweden.
    Puglia, C.
    Uppsala University, Sweden.
    Oscarsson, S.
    Mälardalen University, Department of Biology and Chemical Engineering.
    Activity boost of a biomimetic oxidation catalyst by immobilization onto a gold surface2006In: Journal of Catalysis, ISSN 0021-9517, Vol. 244, no 1, p. 86-91Article in journal (Refereed)
    Abstract [en]

    Thiol-functionalized cobalt porphyrins were used as a model system for investigating catalytic activity in homogeneous and heterogeneous oxidation catalysis. Self-assembled monolayers of thiol-functionallized cobalt porphyrins were prepared on a gold surface and served as heterogeneous catalysts. These immobilized molecules prevented the strong inactivation observed for their homogeneous congener. As a result, the turnover number per molecule in heterogeneous catalysis was at least 100 times higher than that of the corresponding homogeneous catalyst. It is atypical for a heterogenized catalyst to outperform its homogeneous congener. The properties of the molecular layers were characterized on the molecular level by means of X-ray photoelectron spectroscopy (XPS) and scanning tunneling microscopy (STM). The results demonstrate that the performance of these biomimetic catalysts can be dramatically improved if the catalyst arrangement can be controlled on the molecular level.

  • 10.
    Berner, S.
    et al.
    Uppsala University, Uppsala, Sweden.
    Lidbaum, H.
    Uppsala University, Uppsala, Sweden.
    Ledung, G.
    Mälardalen University, School of Sustainable Development of Society and Technology.
    Åhlund, J.
    Uppsala University, Uppsala, Sweden.
    Nilson, K.
    Uppsala University, Uppsala, Sweden.
    Schiessling, J.
    Uppsala University, Uppsala, Sweden.
    Gelius, U.
    Uppsala University, Uppsala, Sweden.
    Bäckvall, J.
    Stockholm University, Sweden.
    Puglia, C.
    Uppsala University, Uppsala, Sweden.
    Oscarsson, Sven
    Mälardalen University, Department of Biology and Chemical Engineering.
    Electronic and structural studies of immobilized thiol-derivatized cobalt porphyrins on gold surfaces2007In: Applied Surface Science, ISSN 0169-4332, Vol. 253, no 18, p. 7540-7548Article in journal (Refereed)
    Abstract [en]

    The immobilisation of thiol-derivatized cobalt porphyrins on gold surfaces has been studied in detail by means of combined scanning tunnelling microscopy (STM) and X-ray photoelectron spectroscopy (XPS). S-thioacetyl has been used as a protective group for the thiol. Different routes for deprotection of the acetyl groups were performed in acidic and in basic conditions. The results show the formation of monolayer films for the different preparation schemes. The immobilisation of the molecules on the gold surface takes place through the thiol-linkers by the formation of multiple thiolate bonds. In the case of layers formed with protected porphyrins approximately 60% of the linkers are bonded to the gold surface whereas for deprotected layers the amount of bonded linkers is increased up to about 80%. STM measurements revealed that the molecules arrange in a disordered overlayer and do not exhibit mobility on the gold surface. Annealing experiments have been performed in order to test the stability of the porphyrin layers. Disordered patterns have been observed in the STM images after annealing at T= 400 degrees C. XPS revealed that the sulphur content disappeared completely after annealing at T= 180 degrees C and that the molecules did undergo significant modifications.

  • 11.
    Bobrova, Irina
    et al.
    Institute of Organic Synthesis, Riga, Latvia .
    Vlaskovska, Mila
    Medical University, Sofia, Bulgaria.
    Kasakov, Lubomir
    Institute of Physiology, Sofia, Bulgaria .
    Surovoy, Andrej
    Institute of Bioorganic Chemistry, Moscow, Russian Federation .
    Egorova, Natalija
    Institute of Bioorganic Chemistry, Moscow, Russian Federation .
    Johansson, LarsErik
    Mälardalen University, Department of Biology and Chemical Engineering.
    Karsnas, Per
    Mälardalen University, Department of Biology and Chemical Engineering.
    Terenius, Lars
    Karolinska Institute, Stockholm, Sweden.
    A structure-activity study of nociceptin-(1-13)-peptide amide. Synthesis of analogues substituted in positions 0, 1, 3, 4 and 10.2003In: European journal of medicinal chemistry, ISSN 0223-5234, Vol. 38, no 7-8, p. 687-694Article in journal (Refereed)
    Abstract [en]

    A series of analogues of nociceptin, Noc(1-13)NH(2) (an agonist at the ORL1 receptor) was synthesized with following modifications: (1) N-terminal extension with Arg(0); (2) replacement of Gly(3) by basic or polar amino acids-Arg, Asn, Lys(For) or deletion; (3) exchange of Phe(1) or Phe(4) by Phe(NO(2)); (4) substitution of Ser(10) with D-Ser, Pro, D-Pro. The analogs were synthesized by solid-phase methodology using Fmoc-amino acid pentafluorophenyl esters. The affinity for the ORL1 and for the kappa, micro and delta-opioid receptors was investigated by radioligand binding assay and bioactivity by a mouse vas deferens (MVD) assay. The addition of the amino acid residue Arg to the N-terminal enhances the opioid receptor affinity of Noc(1-13)NH(2) while retaining ORL1 receptor affinity at a moderate level. The replacement of Gly in position 3 by the basic or polar amino acids-Arg, Asn, Lys(For) or its deletion led to inactive analogues. The replacement of Ser in position 10 by its D-isomer, Pro and D-Pro resulted in a series of analogues with the following order of activity: Ser(10)>D-Ser(10)>Pro(10)>D-Pro(10). In [D-Ser(10)]Noc(1-13)NH(2), introduction of an additional Phe(NO(2))(4) led to a >60-fold increase of ORL1 affinity, completely attenuating the loss of affinity brought about by Ser(10). In other analogues, introduction of Phe(NO(2))(4) did not change the magnitude of ORL1 binding significantly. Generally, while modifications in position 3 frequently led to a loss of most or all bioactivity, modifications in position 0 (Arg(0)) or 4 (Phe(NO(2))(4)) and 10 (D-Ser(10), Pro(10)) are tolerated.

  • 12.
    Borgefjord, Ingela
    et al.
    Mälardalen University, Department of Biology and Chemical Engineering.
    Nyström, Liselotte
    Mälardalen University, Department of Biology and Chemical Engineering.
    Lärarens intressen och prioriteringar i naturkunskapsundervisning: artkunskapen i fokus2008Independent thesis Basic level (degree of Bachelor), 10 points / 15 hpStudent thesis
    Abstract [sv]

    Detta arbete undersöker hur intresset för naturkunskap påverkas av lärares prioriteringar av ämnesstoffet. Fokus i detta arbete ligger på lärarens inställning till artkunskap. Vi tittar också närmre på hur naturundervisningen går till och vad som kan ligga bakom lärarens val. Data i denna undersökning har inhämtats under intervjuer med sju lärare som undervisar i naturkunskap och/eller biologi antingen i grundskolans senare år eller på gymnasiet.

    Studien visar att naturundervisningen påverkas i mindre grad av lärarens eget intresse men däremot i hög grad av vad lärarna tror eleverna är intresserade av.

    Det finns en fara i att prioritera undervisningen efter elevers intresse, då eleverna inte kan hållas ansvariga för konsekvenserna av dessa val. Det är inte lärarens huvuduppgift att göra lektionerna roliga, utan att ge eleverna en god demokratisk grund och insikt om hur deras egna handlingar påverkar dem själva och naturen omkring oss. Lärare har ett stort ansvar över hur stoffet presenteras och vilka undervisningsmoment som läggs i fokus. Läraren kan sedan lägga upp undervisningen efter elevernas individuella behov och där bedriva en demokratisk verksamhet.

    Vi tror att ett större fokus på artkunskap kan väcka elevernas engagemang för den biologiska mångfalden och i ett vidare perspektiv hållbar utveckling.

  • 13.
    Buijs, J
    Mälardalen University, Department of Biology and Chemical Engineering.
    Optical Spectroscopy of Proteins at Interfaces2006In: In " Encyclopedia of Surface and Colloid Science, 2nd edition, Taylor and Francis Group, NY , 2006, p. 4302-4317Chapter in book (Refereed)
  • 14.
    Buijs, Jos
    et al.
    Mälardalen University, Department of Biology and Chemical Engineering.
    Håkansson, Kristina
    Uppsala University, Sweden.
    Hagman, Charlotte
    Uppsala University, Sweden.
    Håkansson, Per
    Uppsala University, Sweden.
    Oscarsson, Sven
    Mälardalen University, Department of Biology and Chemical Engineering.
    A new method for the accurate determination of the isotopic state of single amide hydrogens within peptides using Fourier transform ion cyclotron resonance mass spectrometry2000In: Rapid Communications in Mass Spectrometry, ISSN 0951-4198, Vol. 14, no 19, p. 1751-1756Article in journal (Refereed)
    Abstract [en]

    A new method is presented to accurately determine the probability of having a deuterium or hydrogen atom on a specific amide position within a peptide after deuterium/hydrogen (D/H) exchange in solution. Amide hydrogen exchange has been proven to be a sensitive probe for studying protein structures and structural dynamics. At the same time, mass spectrometry in combination with physical fragmentation methods is commonly used to sequence proteins based on an amino acid residue specific mass analysis. In the present study it is demonstrated that the isotopic patterns of a series of peptide fragment ions obtained with capillary-skimmer dissociation, as observed with a 9.4 T Fourier transform ion cyclotron resonance (FTICR) mass spectrometer, can be used to calculate the isotopic state of specific amide hydrogens. This calculation is based on the experimentally observed isotopic patterns of two consecutive fragments and on the isotopic binomial distributions of the atoms in the residue constituting the difference between these two consecutive fragments. The applicability of the method is demonstrated by following the sequence-specific D/H exchange rate in solution of single amide hydrogens within some peptides.

  • 15.
    Buijs, Jos
    et al.
    Uppsala University, Sweden.
    Ramström, Margareta
    Uppsala University, Sweden.
    Danfelter, Mikael
    Uppsala University, Sweden.
    Larsericsdotter, Helén
    Mälardalen University, Department of Biology and Chemical Engineering.
    Håkansson, Per
    Mälardalen University, Department of Biology and Chemical Engineering.
    Oscarsson, Sven
    Mälardalen University, Department of Biology and Chemical Engineering.
    Localized changes in the structural stability of myoglobin upon adsorption onto silica particles, as studied with hydrogen/deuterium exchange mass spectrometry2003In: Journal of Colloid and Interface Science, ISSN 0021-9797, Vol. 263, no 2, p. 441-448Article in journal (Refereed)
    Abstract [en]

    A new method is presented for monitoring the conformational stability of various parts of a protein that is physically adsorbed onto nanometer-sized silica particles. The method employs hydrogen/deuterium (H/D) exchange of amide hydrogens, a process that is extremely sensitive to structural features of proteins. The resulting mass increase is analyzed with Fourier transform ion cyclotron resonance (FTICR) mass spectrometry. Higher structural specificity is obtained by enzymatically cleaving the adsorbed proteins prior to mass spectrometric analysis. The mass increases of four peptic fragments of myoglobin are followed as a function of the H/D exchange time. The four peptic fragments cover 90% of the myoglobin structure. Two of the peptic fragments, located in the middle of the myoglobin sequence and close to the heme group, do not show any adsorption-induced changes in their structural stability, whereas the more stable C- and N-terminal fragments are destabilized. Interestingly, for the N-terminal fragment, comprising residues 1–29, two distinct and equally large conformational populations are observed. One of these populations has a stability similar to that in solution (−23 kJ/mol), whereas the other population is highly destabilized upon adsorption (−11 kJ/mol).

  • 16.
    buskqvist, ylva
    Mälardalen University, Department of Biology and Chemical Engineering. Mälardalen University, School of Sustainable Development of Society and Technology.
    utomhuspedagogik: en studie om förskollärares kunskap om och inställning till utomhuspedagogik samt hur detta omsätts i praktiken2008Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
  • 17.
    Chabo, Ablahad
    Mälardalen University, School of Sustainable Development of Society and Technology. Mälardalen University, Department of Biology and Chemical Engineering.
    Treatment of a mantle cell lymphoma cell line with cannabinoids and cytostatics: - effects on DNA synthesis and ceramide metabolism2009Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Mantle cell lymphoma (MCL) is an aggressive B-cell malignancy with bad prognosis, which predominates in males with advanced age. However, studies of the endocannabinoid system and how it affects tumour behaviour provides the basis for designing innovative therapeutic strategies that could open new opportunities for treatment of patient with MCL. It has earlier been shown that the cannabinoid receptor ligand (R)-(+)-methanandamide (R-MA) induce cell death in MCL by accumulation of ceramide. Ceramide has a pro-apoptotic effect on the cell but could be metabolized by the enzymes glucosylceramide synthase (GCS) and sphingosine kinase 1 (SphK1) to molecules with pro-proliferative effect. Therefore, treatments with R-MA on Jeko-1 MCL cell line were performed in this study to determine interference in the proliferative behaviour as well as in the gene expression of the enzymes GCS and SphK1. In addition, treatments with chemotherapeutic substances, such as doxorubicin or cytarabine (Ara-C), and combinations of R-MA and chemotherapeutic substance, were performed for the same reason. Results showed that the proliferation behaviour of Jeko cells remained unaffected when treated with R-MA, in contrast to the decreased proliferative effects shown when treated with cytostatics or combinations of R-MA and cytostatics. Furthermore, a tendency for up-regulation of GCS and SphK1 expression was recognized when cells were treated with cytostatics or combination of cytostatics and R-MA, in contrast to cells treated with R-MA alone. Although, R-MA alone had a tendency for a small down-regulation of GCS expression, it contributed to a potential elevation of GCS expression when combined with Ara-C or doxorubicin. It is believed that the effect from upregulated levels of the metabolizing enzymes GCS and SphK1 is balanced by, earlier observed, up-regulations of the ceramide synthesis enzymes.

  • 18.
    de Maré, L
    et al.
    Lund Institute of Technology, Sweden.
    Velut, S
    Lund Institute of Technology, Sweden.
    Ledung, Erika
    Mälardalen University, Department of Biology and Chemical Engineering.
    Cimander, C
    Novozymes Biopharma AB, Lund, Sweden .
    Norrman, Bo
    Mälardalen University, Department of Biology and Chemical Engineering.
    Karlsson, E
    Lund Institute of Technology, Lund, Sweden.
    Holst, O
    Lund Institute of Technology, Lund, Sweden.
    Hagander, P
    Lund Institute of Technology, Sweden.
    A cultivation technique for E. coli fed-batch cultivations operating close to the maximum oxygen transfer capacity of the reactor2005In: Biotechnology Letters, ISSN 0141-5492, Vol. 27, no 14, p. 983-990Article in journal (Refereed)
    Abstract [en]

    A cultivation strategy combining the advantages of temperature-limited fed-batch and probing feeding control is presented. The technique was evaluated in fed-batch cultivations with E. coli BL21(DE3) producing xylanase in a 3 liter bioreactor. A 20% increase in cell mass was achieved and the usual decrease in specific enzyme activity normally observed during the late production phase was diminished with the new technique. The method was further tested by growing E. coli W3110 in a larger bioreactor (50 l). It is a suitable cultivation technique when the O2 transfer capacity of the reactor is reached and it is desired to continue to produce the recombinant protein.

  • 19.
    Delsö, Emelie
    et al.
    Mälardalen University, Department of Biology and Chemical Engineering.
    Tengstrand, Caroline
    Mälardalen University, Department of Biology and Chemical Engineering.
    Utomhuspedagogik: Användandet av uterummet i den dagliga verksamheten2008Independent thesis Basic level (degree of Bachelor), 10 points / 15 hpStudent thesis
    Abstract [sv]

    Det som vi vill belysa med denna undersökning är hur viktigt det är att använda uterummet för elevers utvecklande i sin helhet. Det är viktigt att tänka på skolgården som ett extra klassrum. Vi vill belysa det faktum att uteverksamhet i skolan är gynnsamt för barnen. Något som vi vill ta upp kring utomhuspedagogiken är problematiken kring att arbeta ute och även ge en bättre bild av vad utomhuspedagogik betyder. Undersökningen har utförts i två skolor i Mellansverige. Vi har använt oss av en kvalitativ undersökning och det material vi använt oss av är 18 enkätformulär och 4 intervjuer.

    Vår undersökning visar att även om pedagogerna anser att det är bra att vara utomhus så förekommer det väldigt sällan. Detta trots att pedagogerna själva anser att de skulle ha tid att gå ut med barnen mer. Pedagogerna anser att uterummet har en betydande roll för elevernas lärande. Respondenterna menar att utomhuspedagogik handlar om att bedriva en sorts pedagogiks verksamhet, utomhus med eleverna.

    Vi vill framhålla att utomhuspedagogik är intressant, roligt, kreativt och nyskapande för både elever och pedagoger.

  • 20.
    Dilanson, Nadea
    Mälardalen University, Department of Biology and Chemical Engineering. Mälardalen University, School of Sustainable Development of Society and Technology.
    Halfsphere Derivatisation of Magnetic Micro Particles2008Independent thesis Advanced level (professional degree), 20 points / 30 hpStudent thesis
    Abstract [en]

    Abstract

     

    This exam project is an effort to derivatize one side of magnetic beads with one kind of molecule  , and another one on the opposite side. First the surface of the sphere is loaded with a suitable linker with, e.g. amino or hydroxyl groups. In the second step, these groups are derivatized with a photosensitive protecting group such as Nitroveratryloxycarbonyl. In the third step, the particles are placed on a surface and then irradiated with UltraViolet light (320 nm) from above, which will cleave off the Nitroveratryloxycarbonyl on the upper half, while leaving in place the ones at the lower half. The linker groups of the upper half can now be derivatized by other reagents of choice. The remaining Nitroveratryloxycarbonyl groups can be removed by suspending the particles in a solvent and then exposing them to UltraViolet light. Finally the linker groups on this half of the particles can be derivatized by a second reagent.

    Magnetic particles were marked with FITC, two different kinds of magnetic particles were selected, sikastar-NH2 function and sikastar-COOH function. Five different solvents were used to wash the magnetic particles and remove the bounded FITC, solvents are Acetone, 1-butanol, DMSO, 4-propanol, and Urea. Magnetic particles sikastar-NH2 and sikastar-COOH were washed with Tween 20 and SDS to remove non-specific binding of FITC. Sikastar particles were treated with IgG*FITC in constant presence of the following solvents: PBS*10, Pluronic-F127, Tween 20. Pegylation of sikastar particles got done to reduce non-specific binding. Derivatisation of Nitroveratryloxycarbonyl got done and specific bindning of IgG*FITC to micromer particles got done by protein thiolation.

    When a different concentration of FITC was tested to control specific and non-specific binding to sikastar functions, we observed that we had a specific binding to sikastar-NH2 in the lowest concentration. In choice of magnetic particles we had specific binding with sikastar-NH2. Using a different solvents Acetone, 1-butanol, 4-propanol, and Urea  to remove bounded FITC, sikastar-NH2 showed stronger fluoresence than sikastar-COOH after washing because of specific binding and it was difficult to remove FITC with Acetone, 1-butanol,  4-propanol,and Urea, on the other hand DMSO could remove bounded FITC from sikastar particles. When we washed magnetic particles sikastar-NH2 and sikastar-COOH with Tween 20 and SDS to remove non-specific binding of FITC, we could see that magnetic particles showed fluoresence in both functions due to non-specific binding. When sikastar particles got treated with IgG*FITC in constant presence of solvents PBS*10, Pluronic-F127, and Tween 20, we had a specific binding between sikastar particles and IgG*FITC in a presence of pluronic-F127. Pegylation of sikastar particles with a different kind of a PEG was possibl to reduce non-specific bindning. The derivatisation of Nitroveratryloxycarbonyl could be done in a N2 environment, and Nitroveratryloxycarbonyl-sikastar-NH2 could be radiated with UltraViolet light to remove Nitroveratryloxycarbonyl. Also thiolation method could be used to perform specific binding of IgG*FITC to micromer particles.

  • 21.
    Ekaterina, van der Haagen
    Mälardalen University, Department of Biology and Chemical Engineering.
    ”Processutveckling av metod f?r tillverkning av en funktionell tibetansk mejeriprodukt”2009Independent thesis Advanced level (professional degree), 30 credits / 45 HE creditsStudent thesis
    Abstract [en]

    Probiotics is a special group of health products on the market. The most common type of  these is live cultures of lactic acid fermenting bacteria from raw milk . These include, among others, yogurt and various trademarks such as Hälsofil ®, Acidophilus ®, Dofilus ® and Kefir ®. Such products are often used by patients who are treated with antibiotics to combat the intestinal flora eliminated, thus causing digestive problems. The present work deals with yet another type of health product, viz. kefir of Tibetan type. A literature review of mainly Russian sources has been made to identify the nutrients and potential health benefits of kefir consumption in humans. The study sought to find data on the nutritional values of this very particular culture of a certain fungus, Zoogloea ramigera and some species of the genus Lactobacillus. However, this has not been found other than the data on the product, which is on the Swedish market under the brand Kefir, which is a product of a different nature than the Tibetan form of kefir. One source indicates, however, that among other things, it contains vitamin D, which would otherwise break down in this type of product. Part of the work is a study of the characteristics of the kefir culture for an intended technological process of production. The study shows that culture can be stored while maintaining viability by freezing to -70 ⁰ C. The culture is not affected by Gentamycin, which is a common antibiotic. Kefir culture tends to grow in the form of granules or lumps, which may be separated and reused for production. It is sensitive to metal ions, so that process equipment, intended for contact with kefir must be manufactured from other materials such as enamel or polymer-coated steel sheets. A study of cultural interaction with three different strains of intestinal bacteria showed very little impact on the cultivation on agar plate. In batch fermentation the pH of the kefir culture decreases to 3.4, which is slightly higher than the pKa of lactic acid. This pH is unfavorable for disease-causing bacteria and can be expected to limit growth of those in the human gastrointestinal tract upon ingestion.

  • 22.
    Essö, Carola
    Mälardalen University, Department of Biology and Chemical Engineering.
    Modifying Polydimethylsiloxane (PDMS) surfaces2007Independent thesis Basic level (professional degree), 20 points / 30 hpStudent thesis
    Abstract [en]

    The aim of the project was to modify polydimethylsiloxane (PDMS) surfaces in order to minimize adsorption of proteins. PDMS is used in micro-fluidic devices that control the delivery of samples to a sensor chip in Biacore instrumentation. These instruments are used to characterize interactions between biomolecules with a detection principle based on surface plasmon resonance (SPR). To minimize adsorption of proteins poly-ethylene-oxide (PEO) based surfactants, were added to the buffer. The added PEO surfactants were P20, Pluronic F-127 and Brij 35. Interaction of these surfactants with the sensor chip in Biacore instruments was also examined. Creating a more hydrophilic surface layer on PDMS by oxidation was also examined.

    When surfactants were continuously added to protein samples, as in dynamically coating of PDMS surfaces, Brij 35 resulted in the strongest reduction in protein adsorption. Brij 35 was also the surfactant that was easiest to remove from both PDMS and the sensor surfaces. Pluronic bound strongest to surfaces, and is most suitable when only adding surfactant to the buffer in a pre-coating step. All surfactants did reduce protein adsorption considerably (99% or more) and addition is necessary when working with protein solutions and hydrophobic surfaces as PDMS. Another alternative is oxidation of PDMS surface, which is an easy procedure that decreased the protein adsorption to about 10% compared to adsorption to untreated surface.

  • 23.
    Fischer, Torkel
    Mälardalen University. Mälardalen University, School of Sustainable Development of Society and Technology. Mälardalen University, Department of Biology and Chemical Engineering.
    Boplatsval hos solitära getingar, bin och rovsteklar2009Independent thesis Advanced level (degree of Master (One Year)), 20 credits / 30 HE creditsStudent thesis
    Abstract [sv]

    Denna undersökning gjordes för att studera solitära steklars boplatsval speciellt med avseende på spatiala mönster. Aggregat av lämpliga bohål (bibatterier) tillverkades och gjordes tillgängliga förfrilevande steklar. Resultatet visade att steklar tenderar att anlägga bon i närheten av andra stekelbon. Ingen tendens fanns att anlägga bon i centralt belägna positioner. Steklarna verkar också föredra att anlägga bon till vänster om en tänkt mittllinje på bibatterierna. Aggregation kan vara ett sätt att undgå parasitering och predation vid boplatsen. Om detta orsakade aggregationstendensen var det dock något oväntat att inte också en central tendens kunde påvisas. Att steklarna föredrog bohål i bibatteriernas vänstra del är svårt att förklara.

  • 24.
    Forsman, Jonas
    et al.
    Mälardalen University, Department of Biology and Chemical Engineering.
    Frisk Engelbrektsson, Rickard
    Mälardalen University, Department of Biology and Chemical Engineering.
    Fysikundervisning ur ett kulturperspektiv: (Physics education cultures – A study of tuition culture)2007Independent thesis Basic level (professional degree), 10 points / 15 hpStudent thesis
    Abstract [en]

    This essay surveys physics science education in the light of cultures. A multivariate analysis –

    principal component analysis – has been used to map out the different cultures in middle

    school and high school. The main purpose of this essay is to examine differences and

    similarities between the different physics educational cultures found in the survey. Through

    examining literature and prior research, it is also the purpose to examine what possibilities

    and problems these physics educational cultures might impose on students and teachers.

    Border-crossing has been a central concept in explaining how possible cultural bordercrossings

    might affect the teachers and pupils.

    The survey has found four different kinds of physics educational cultures which are:

    ‘Praktikerna’, ‘Ämnesinriktade’, ‘Anpassarna’ and ‘Återkopplarna’. These physics

    educational cultures are not dependent of sex, age, appropriate teacher education or

    experience. However there is a connection between which grades the teacher educates but

    only for the physics educational cultures ‘Anpassarna’ and ‘Praktikerna’. The survey also

    discovered that the physics educational cultures ‘Ämnesinriktade’ and ‘Anpassarna’ has to

    some degree a connection to earlier examined science-cultures. ‘Återkopplarna’ seems to be a

    mixture of the other three described physics educational cultures. Since cultural bordercrossings

    do occur between the described educational cultures, the problems associated with

    border-crossings also exist. The problems which are associated with border-crossings are: that

    pupils and teachers don’t recognize each other’s physics educational cultures. These bordercrossings

    are described in light of both the teachers’ points of view and the pupils’ points of

    view.

  • 25.
    Gajardo Gunnarsson, Tania
    Mälardalen University, Department of Biology and Chemical Engineering.
    identifiering av genetisk markör för könsbestämning av Gasterousteus aculeatus2008Independent thesis Advanced level (degree of Magister), 20 points / 30 hpStudent thesis
    Abstract [sv]

    Arbetets uppgift var att identifiera en DNA-sekvens som skulle kunna finnas hos storspiggens könsbestämningsregion. Avsikten med detta arbete är att utveckla en enkel PCR-baserad metod för att kunna könsbestämma storspiggar genetiskt. Tidigare genetiska studier har visat en skillnad mellan honor och hanar vid jämförelse av deras RAPD-3 PCR produkter. Skillnaden består i att endast hanarna har ett fragment som är runt 250 bp stort. Detta fragment ska isoleras, renas, klonas och sekvenseras med hjälp av olika metoder. Sekvensen ska användas för att beställa designerade primer som testades för att vara specifika för hanar.

    I detta arbete kunde endast en sekvens användas för detta syfte och två egendesignerade primers beställdes, dessa visade sig dock icke vara specifika för hanar.

  • 26.
    Ghafoory, Shima
    Mälardalen University, School of Sustainable Development of Society and Technology. Mälardalen University, Department of Biology and Chemical Engineering.
    Development of a screening assay for inhibitors of inflammation useful against pancreatic cancer2009Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Pancreatic cancer is the fourth most lethal cancer and ranks as the eighth most commonly diagnosed cancer worldwide. This is due to its rapid proliferation, strong metastatic potential and its delayed detection. One major risk factor for developing pancreatic cancer is the aggressive inflammatory disease chronic pancreatitis. Chronic inflammation frequently precedes the development of certain pancreatic cancers.

    Inflammation is a protective and necessary process by which the body can alert the immune system of the existence of a wound or infection and mount an immune response to remove the harmful stimuli and start wound healing. The cross-talking of cells of the immune system and infected cells happens through cytokines, soluble proteins that activate and recruit other immune cells to increase the system’s response to the pathogen. Failure to resolve the injury can result in persistent cytokine production that in turn allows a cell that is damaged or altered to survive when in normal conditions it would be killed. Inflammation is thought to create a microenvironment that facilitates the initiation and/or growth of pancreatic cancer cells.

    Cytokines use two important kinases for their signaling: Janus Kinases (JAKs) and Signal Transducers and Activators of Transcription (STATs). The JAKs are activated upon the binding of cytokines to their corresponding receptors. When activated, the JAKs activate STATs through tyrosine phosphorylation. The STATs transduce signals to the nucleus of the cells to induce expression of critical genes essential in normal physiological cellular events such as differentiation, proliferation, cell survival, apoptosis and angiogenesis. STAT3 (a member of the STAT family) is constitutively activated in some pancreatic cancers, promoting cell cycle progression, cellular transformations and preventing apoptosis. Therefore, STAT3 is a promising target for cancer treatment. Novel therapies that inhibit STAT3 activity in cancers are urgently needed. Natural products are a very good resource for the discovery of new drugs against pancreatic cancer.

    Covering more than 70% of the Earths surface, The Ocean is an excellent source of bioactive natural products. Harbor Branch Oceanographic Institute’s Center for Marine Biomedical and Biotechnology Research (HBOI-CMBBR) situated in Florida, aims to find new marine natural products useful in disease prevention and drug therapy. Their current focus is to look for novel treatments for preventing both the formation of new pancreatic tumors and the metastasis of existing tumors.

    The hypothesis of this degree project was that novel inhibitors of STAT3 useful in the treatment of pancreatitis and/or pancreatic cancer could be found from marine-natural products. The first specific aim of this degree project was to set up an assay to identify bioactive marine natural products as inhibitors of inflammation. Furthermore the assay was validated using a commercially available inhibitor of inflammation (Cucurbitacin I). The last aim was to further validate the assay by screening pure compounds and peak library material from the HBOI marine specimen collection.

    At the end of the experimentation time, the assay still was not set-up as there were difficulties in proper cell culture techniques and the cell line did not respond as advertised. While the results were not as expected, the work performed resulted in familiarization with research laboratory practices and increased laboratory skills. Moreover, the results from the assays point to future directions to accomplish this project.

  • 27.
    Ghalali, Aram
    Mälardalen University, Department of Biology and Chemical Engineering. Mälardalen University, School of Sustainable Development of Society and Technology.
    STATINS AND INCREASED EFFICACY OF CANCER TREATMENT2008Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Abstract

    Activation of the PI3K/Akt signaling cascade is often associated with advanced forms of prostate cancer cells, DU145. This is likely explained by the common loss of the PTEN gene in majority of cancer cells. This study have documented that low concentration of atorvastatin, a drug inhibiting HMG-CoA reductase and cholesterol metabolism, decreased the level of insulin-induced phosphorylated Akt in the nucleus.

    The statins effect on Akt/protein kinase B signaling and the sensitizing effect of cytostatic drugs have been investigated in this study and it were found that cytostatic drugs induced Akt phosphorylation and nuclear translocation was inhibited by atorvastatin in A549 and DU145 cells. Inhibition of PI3K with LY294002 was observed by MTT assay, and it were noticed that atorvastatin increased the effect of LY294002.

    The main point of the study was the localization of the tumor suppressor PTEN. This gene acts as a plasma-membrane lipid-phosphatase antagonizing the phosphoinositide 3-kinase/Akt cell survival pathway. The nuclear localization of PTEN is a central for its activity. The insulin-induced A549 cells were treated with atorvastatin, thereafter very rapid change in PTEN localization was observed.

    The study is preformed in view of good laboratory practice, GLP. In this study GLP applies to non-clinical experiment conducted for the assessment of the safety of chemicals (the concentration of the atorvastatin) to man and the environment.

     

  • 28.
    Gunnarsson, K
    et al.
    Uppsala University, Sweden.
    Roy, P.E.
    Uppsala University, Sweden.
    Felton, S.
    Uppsala University, Sweden.
    Pihl, J.
    Uppsala University, Sweden.
    Svedlindh, P.
    Uppsala University, Sweden.
    Berner, S
    Mälardalen University, Department of Biology and Chemical Engineering. Uppsala University, Sweden.
    Lidbaum, H.
    Uppsala University, Sweden.
    Oscarsson, S
    Mälardalen University, Department of Biology and Chemical Engineering. Uppsala University, Sweden.
    Programmable motion and separation of single magnetic particles on patterned magnetic surfaces2005In: Advanced Materials, ISSN 0935-9648, Vol. 17, no 14, p. 1730-1734Article in journal (Refereed)
    Abstract [en]

    Motion of single micrometer-sized magnetic particles on patterned magnetic surfaces is controlled by a rotating magnetic field (see Figure and cover). Patterns of thin-film magnetic elements are tailored to form transport lines. Individual particles are separated by adding junctions to the transport lines. The method can improve existing applications in biotechnology and generate new ones in life sciences.

  • 29.
    Göransson Fladvad, Anne
    Mälardalen University, Department of Biology and Chemical Engineering.
    Effektiv batchdokumentation2008Independent thesis Basic level (professional degree), 20 points / 30 hpStudent thesis
    Abstract [sv]

    Sammanfattning

    Titel: Effektiv Batchdokumentation

    Handledare: Annette Elmqvist

    Examinator: Sven Hamp

    Problemformulering: De problemformuleringar varit utgångspunkt för arbetet är:

    • Kan dokumentationen struktureras på ett bättre sätt och effektiviseras.

    • Kan befintlig dokumentation delas upp för att skapa effektivare flöde

    Syfte och mål: Syftet med detta examensarbete är att utveckla en bättre struktur för GMP styrande dokumentation avseende tillverkningsmetod, kontrollprotokoll och instruktioner för tillverkning av valt intermediat i ett automatiserat system som uppfyller kraven på både lättförstålighet och effektivitet.

    Metod: Genom intervjuer med operatörer inom företaget och på andra företag ta fram nya rutiner för utarbetande och effektivisering av dokumentationsprocessen. Genom litteraturstudier definiera väsentlig krav på dokumentationsprocessen enligt GMP.

    Slutsatser: Det går att effektivisera dokumentationsprocessen för vald tillverkning. Det går att dela upp dokumentationen och särskilja uppvägning och analyser. Ansatserna i problemformuleringen kan med rimlig arbetsinsats uppnås. En förändring av dokumentationsprocessen är företagsekonomiskt motiverad och samtidigt viktig för att den underlättar kvalitetsuppföljning genom dokumentationsanalys.

    Målgrupp: Rapporten är i första hand ämnad för produktions- och kvalitetsledningen för implementering i organisationen. Men den kan även utgöra stöd för de grupper som kan komma att få i uppdrag att se över olika dokumentationsförfaranden inom företaget.

  • 30.
    Göthelid, Emmanuelle
    et al.
    Mälardalen University, Department of Biology and Chemical Engineering.
    Benito, N
    Universidad Miguel Hernández de Elche, Bio-Engineering Institute, Valencia KM.87, 03550 Alicante, Spain.
    Gonzalez, D
    Universidad Miguel Hernández de Elche, Bio-Engineering Institute, Valencia KM.87, 03550 Alicante, Spain.
    Fernandez, E
    Universidad Miguel Hernández de Elche, Bio-Engineering Institute, Valencia KM.87, 03550 Alicante, Spain.
    Granstam, Cecilia
    Mälardalen University, Department of Biology and Chemical Engineering.
    Chow, Winnie
    Mälardalen University, Department of Biology and Chemical Engineering.
    Geuens, D
    Uppsala University.
    Neves, H
    Uppsala University.
    Oscarsson, Sven
    Mälardalen University, Department of Biology and Chemical Engineering.
    Hyaluronic acid Grafting on Silicon Surfaces: Towards an Increased Biocomp of Brain Micro-Electorde arrays2008In: 8th World Biomaterials Congress 2008, Volume 2, 2008, p. 1081-Conference paper (Other (popular science, discussion, etc.))
  • 31.
    Hagerman, Malin
    Mälardalen University, Department of Biology and Chemical Engineering. Mälardalen University, School of Sustainable Development of Society and Technology.
    Identifiering och förslag till lösning av ett vattenreningsproblem vid ett slakteri2008Student thesis
  • 32.
    Helena, Stärner
    et al.
    Mälardalen University, Department of Biology and Chemical Engineering.
    Påhlsson, Carl
    Mälardalen University, Department of Biology and Chemical Engineering.
    Lindén, Mats
    Mälardalen University, Department of Biology and Chemical Engineering.
    Tandem repeat polymorphism and heteroplasmy in the mitochondrial DNA control region of threespine stickleback (Gasterosteus aculeatus)2004In: Behaviour: An International Journal of Behavioural Biology, ISSN 0005-7959, Vol. 141, no 11-12, p. 1357-1369Article in journal (Refereed)
    Abstract [en]

    Length polymorphism and heteroplasmy (multiple forms within a single individual) in the mitochondrial DNA (mtDNA) control region have been reported for several species of fish. In this report we demonstrate its existence in the threespine stickleback (Gasterosteus aculeatus). The repeat region, responsible for the length variation and heteroplasmy is located near the 5´ end of the control region and consists of slightly imperfect palindromic sequences. The repeat sequences vary in copy number from 1.5 to 16.5 and are capable of forming secondary structures. All individuals examined were heteroplasmic for 4 or more different copy number of repeats. Our results indicate that the repeats are a result of frequent competitive misalignment in the repeat region prior to replication and support the “illegitimate elongation model” as an explanation of the origin and maintenance of length heteroplasmy in the 5´ end of the control region.

  • 33.
    Holmlund, Anna
    Mälardalen University, School of Sustainable Development of Society and Technology. Mälardalen University, Department of Biology and Chemical Engineering.
    Molecular interactions of proinsulin C-peptide2008Independent thesis Advanced level (degree of Master (One Year)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The proinsulin C-peptide has long been thought as a byproduct from the insulin synthesis were it promotes the folding of the A and B-chain of insulin, but several studies in the past decade has shown that C-peptide is a bioactive peptide that can be beneficial in preventing diabetes complications. Patients with type I diabetes mellitus that has received C-peptide doses has shown for example improved renal function, increased blood flow in skeletal muscle and stimulated glucose transport. The aim of this study was to investigate the inter- and intramolecular binding properties of the proinsulin C-peptide, and in particular to study if the peptide forms oligomers and how the oligomerization is affected by additatives such as metal ions, insulin and sodium chloride. A method to identify C-peptide by SDS- and Native PAGE was developed. Using this technique, proinsulin C-peptide was found to form oligomers in μM concentrations. The oligomerization was dependent on the concentration, time and temperature. Metal ions such as Mg+, Zn2+ and Fe2+ affected the oligomerization. Insulin was shown to affect the oligomeric states of the C-peptide and to promote its disaggregation. Oligomerization of C-peptide was also detected with Surface Plasmon Resonance. Further studies are needed to find out how these finding can relate to the bioactivity of C-peptide.

  • 34. Jensen, J.
    et al.
    Sanz, R.
    Martin, D.
    Surpi, Alessandro
    Mälardalen University, Department of Biology and Chemical Engineering.
    Kubart, T.
    Vazquez, M.
    Hernandez-Velez, M.
    Implantation of anatase thin film with 100 keV Fe-56 ions: Damage formation and magnetic behaviour2009In: Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, ISSN 0168-583X, E-ISSN 1872-9584, Vol. 267, no 16, p. 2725-2730Article in journal (Refereed)
    Abstract [en]

    We have investigated the damage morphology and magnetic properties of titanium dioxide thin films following implantation with Fe ions. The titanium dioxide films, having a polycrystalline anatase structure, were implanted with 100 keV Fe-56(+) ions to a total fluence of 1.3 x 10(16) ions/cm(2). The ion bombardment leads to an amorphized surface with no indication of the presence of secondary phases or Fe clusters. The ion-beam induced damage manifested itself by a marked change in surface morphology and film thickness. A room temperature ferromagnetic behaviour was observed by SQUID in the implanted sample. It is believed that the ion-beam induced damage and defects in the polycrystalline anatase film were partly responsible for the observed magnetic response. 

  • 35.
    Johansson, LarsErik
    et al.
    Mälardalen University, Department of Biology and Chemical Engineering.
    Aldaeus, F
    Royal Institute of Technology, Sweden.
    Jonsson, G
    Mälardalen University, Department of Mathematics and Physics.
    Hamp, S
    Mälardalen University, Department of Biology and Chemical Engineering.
    Roeraade, J
    Royal Institute of Technology, Sweden.
    Determination of conductivity of bacteria by using cross-flow filtration2006In: Biotechnology letters, ISSN 0141-5492, E-ISSN 1573-6776, Vol. 28, no 8, p. 601-603Article in journal (Refereed)
    Abstract [en]

    An important property of the bacterial surface is its conductivity. To obtain reliable conductivity values, it is essential to handle the cells as gently as possible during the measurement procedure. We have developed a method where a standard conductivity meter is used in combination with cross-flow filtration, thus avoiding repeated centrifugation and resuspension. With this method, the conductivity of Bacillus subtilis was determined to be 7000 mu S/cm, which is a deviation from previously published data by almost an order of a magnitude.

  • 36. Jönsson, Mats
    et al.
    Aldaeus, Fredrik
    Johansson, Lars-Erik
    Mälardalen University, Department of Biology and Chemical Engineering.
    Lindberg, Ulf
    Roeraade, Johan
    Bäcklund, Ylva
    Hamp, Sven
    Mälardalen University, Department of Biology and Chemical Engineering.
    Jonsson, Gunnar
    A study of biological particles in a bio-MEMS device using dielectrophoresis2004In: Proceedings of the Fifth Micro Structure Workshop (MSW) 2004, 2004Conference paper (Other academic)
  • 37.
    Karlsson, Anders
    Mälardalen University, Department of Biology and Chemical Engineering. Mälardalen University, School of Sustainable Development of Society and Technology.
    Adhesion av mikroorganismer till lignocellulosa2008Independent thesis Advanced level (degree of Master (One Year)), 20 points / 30 hpStudent thesis
    Abstract [en]

    The aim of the project was to develop a method to investigate differences in adhesion of microorganisms to materials that contains lignocellulose. The method was tested on a gram-positive (Micrococcus lutea) and one gram-negative (E-coliJM109) bacteria.

    The study was begun by cultivation of the two microorganisms. The cultivation was done to calculate the generation times of the bacteria and to obtain growth curves. Cells from these cultivations were also frozen (-70ºC) and later used for inoculation.

    At STFI-Packforsk AB the total charge on the mass was measured and later a conductivity titration on the mass was executed as well, all to find out more about the different properties of the mass. Properties that in a later part of this study could possibly be linked to the adhesion of cells to the pulp. The adhesion experiments that were executed gave poor results. The adhesion experiment with M. lutea was the only experiment that gave a reproducible result. In this experiment M. lutea was contacted with bleached leaf. A reduction of cells was observed in all of the dilutions where M. lutea had been in contact with the mass. The number of colony forming units of the culture was 1,2×107 before the adhesion and 2×106 subsequently.

     

  • 38.
    Karlsson, Ann-Charlotte
    Mälardalen University, Department of Biology and Chemical Engineering.
    Släck inte den eld som brinner...: – en studie av lärares syn på miljöetiska frågor.2007Independent thesis Basic level (degree of Bachelor), 10 points / 15 hpStudent thesis
    Abstract [sv]

    Det som undersökts i denna studie är lärares sätt att se på miljöetiska frågor. Studien syftar till att utreda om detta är bundet till någon ämnesgrupp, någon bakgrund eller deras personliga ställningstaganden. Undersökningen har utförts bland lärare som undervisar på grundskolans senare år. Metoden som använts är en kvantitativ metod. Det empiriska materialet utgörs av 76 enkäter som har insamlats från fem skolor i en mellansvensk kommun. Studien visade att lärare tycker att miljöetiska frågor är viktiga men att de i praktiken har ett begränsat utrymme. Sociala faktorer, värderingar och intressen tycks vara viktiga för förekomsten av miljöinslag i undervisningen. Det som också framkom i resultatet av studien är att ma/no-lärares åsikter skiljer sig från de andra lärarnas, detta inte nödvändigtvis för att de är ma/no-lärare utan möjligen för att det finns ett intresse i grunden.

  • 39.
    Karlsson, Patrik G.
    et al.
    Uppsala University.
    Göthelid, Emmanuelle
    Mälardalen University, School of Sustainable Development of Society and Technology. Mälardalen University, Department of Biology and Chemical Engineering.
    Richter, Jan H.
    Uppsala University.
    Sandell, Anders
    Uppsala University.
    Initial stages of ZrO2 chemical vapour deposition on Si(100)-(2x1) from zirconium tetra-tert-butoxide.2008In: Surface Science, Vol. 602, no 10, p. 1803-1809Article in journal (Refereed)
    Abstract [en]

    The initial stages of chemical vapor deposition of ZrO2 from zirconium tetra-tert-butoxide (ZTB) on Si(100)-(2x1) have been studied by Scanning Tunneling Microscopy (STM) and synchrotron radiation excited Photoelectron Spectroscopy (PES). The STM images and core level (PES) spectra indicate that the predominant surface modifications induced by ZTB are due to silicon carbonization and formation of zirconium dioxide. The carbonization reaction leads to formation of subsurface carbon and two types of reconstructions are discussed: dimer vacancies and dimer vacancies in conjunction with a rotated surface Si-dimer. Indications for the formation of small amounts of zirconium silicide are also found. No evidence for silicon oxidation can be observed with PES, in contrast to the interface properties previously found after larger exposures to ZTB.

  • 40.
    Kuric, Enida
    Mälardalen University, Department of Biology and Chemical Engineering. Mälardalen University, School of Sustainable Development of Society and Technology.
    The Impact of Enriched environment on Lipid metaboilsm after Experimental Stroke2009Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Stroke is the major cause of serious long-term disability with a sufficient acute treatment for only a very limited number of patients. Limited recovery of neurological functions occurs and can be elevated by a permissive post-stroke milieu. Housing animals in an enriched environment modulates regenerative mechanisms in the nonischemic peri-infarct area which might be an attractive target for pharmacological treatments to promote recovery.

    Upon ischemia, cellular lipids are released due to massive cell damage and free lipids significantly contribute to the progression of acute and delayed cell death. The aim of this study was to evalute the effect of enriched environment on lipid metabolism. In particular we characterize the activation of the transcription factor liver X receptor (LXR) in glial scar formation and regulation of cholesterol balance of relevance for functional recovery following stroke.                                      Brain tissues from animals subjected to permanent occlusion of middle cerebral artery (pMCAo) were analysed for LXRα and β protein expression. We found an upregulation and an increased transcriptional activity of LXRβ in the peri-infarct area of rats housing in an enriched environment following pMCAO. Our data anticipate that enriched environment may have positive effects on lipid recycling in the ischemic hemisphere following experimental stroke.

  • 41.
    Larsericsdotter, Helén
    et al.
    Mälardalen University, Department of Biology and Chemical Engineering.
    Oscarsson, Sven
    Mälardalen University, Department of Biology and Chemical Engineering.
    Buijs, Jos
    Mälardalen University, Department of Biology and Chemical Engineering. Uppsala University, Sweden.
    Thermodynamic analysis of lysozyme adsorbed to silica2004In: Journal of colloid and interface science, ISSN 0021-9797, Vol. 276, no 2, p. 261-268Article in journal (Refereed)
    Abstract [en]

    The structural stability of hen egg white lysozyme in solution and adsorbed to small colloidal silica particles at various surface concentrations was investigated using hydrogen-deuterium (H/D) exchange in combination with mass spectrometry (HDX-MS) and differential scanning calorimetry (DSC). The combination of HDX-MS and DSC allows a full thermodynamic analysis of the lysozyme structure as both the enthalpy and the Gibbs free energy can be derived from the various measurements. Moreover, both HDX-MS and DSC provide information on the relative structural heterogeneity of lysozyme in the adsorbed state compared to that in solution. Results demonstrated that at high surface coverage, the structural stability of lysozyme was only marginally affected by adsorption to silica particles whereas the unfolding enthalpy decreased by more than 10%, meaning that the entropy of lysozyme increased with a similar value upon adsorption. Furthermore, the structural heterogeneity increased considerably. At lower surface concentrations, the structural heterogeneity increased further whereas the enthalpy of unfolding decreased. Further analyses of the HDX-MS experiments clearly indicated that folding/unfolding of lysozyme occurs through a two-domain process. These two domains had a similar amount of structural elements and a difference in stabilization energy of 8 kJ/mol, regardless if lysozyme was in solution or adsorbed to silica.

  • 42.
    Larsericsdotter, Helén
    et al.
    Mälardalen University, Department of Biology and Chemical Engineering.
    Oscarsson, Sven
    Mälardalen University, Department of Biology and Chemical Engineering.
    Buijs, Jos
    Mälardalen University, Department of Biology and Chemical Engineering. Uppsala University,, Sweden.
    Thermodynamic Analysis of Proteins Adsorbed on Silica Particles: Electrostatic Effects.2001In: Journal of colloid and interface science, ISSN 0021-9797, Vol. 237, no 1, p. 98-103Article in journal (Refereed)
    Abstract [en]

    Electrostatic effects on protein adsorption were investigated using differential scanning calorimetry (DSC) and adsorption isotherms. The thermal denaturation of lysozyme, ribonuclease A (RNase), and alpha-lactalbumin in solution and adsorbed onto silica nanoparticles was examined at three concentrations of cations: 10 and 100 mM of sodium and 100 mM of sodium to which 10 mM of calcium was added. The parameters investigated were the denaturation enthalpy (DeltaH), the temperature at which the denaturation transition was half-completed (T(m)), and the temperature range of the denaturation transition. For lysozyme and RNase, adsorption isotherms depend strongly on the ionic strength. At low ionic strength both proteins have a high affinity for the silica particles and adsorption is accompanied by a 15-25% reduction in DeltaH and a 3-6 degrees C decrease in T(m), indicating that the adsorbed state of the proteins is destabilized. Also, an increase in the width of the denaturation transition is observed, signifying a larger conformational heterogeneity of the surface bound proteins. At higher ionic strengths, both with and without the addition of calcium, no significant adsorption-induced alteration in DeltaH was observed for all three proteins. The addition of calcium, however, decreases the width of the denaturation transition for lysozyme and RNase in the adsorbed state.

  • 43.
    Larseriksdotter, Helén
    et al.
    Mälardalen University, Department of Biology and Chemical Engineering.
    Jansson, Östen
    Biacore AB, Sweden.
    Zhukov, Andrei
    Biacore AB, Sweden.
    Areskoug, Daphne
    Biacore AB, Sweden.
    Oscarsson, S
    Mälardalen University, Department of Biology and Chemical Engineering.
    Buijs, J
    Biacore AB, Sweden.
    Optimizing the surface plasmon resonance/mass spectrometry interface for functional proteomics applications2006In: Proteomics, ISSN 1615-9853, Vol. 6, no 8, p. 2355-2364Article in journal (Refereed)
    Abstract [en]

    A great challenge in functional or interaction proteomics is to map protein networks and establish a functional relationship between expressed proteins and their effects on cellular processes. These cellular processes can be studied by characterizing binding partners to a "bait" protein against a complex background of other molecules present in cells, tissues, or biological fluids. This so-called ligand fishing process can be performed by combining surface plasmon resonance biosensors with MS. This combination generates a unique and automated method to quantify and characterize biomolecular interactions, and identify the interaction partners. A general problem in chip-based affinity separation systems is the large surface-to-volume ratio of the fluidic system. Extreme care, therefore, is required to avoid nonspecific adsorption, resulting in losses of the target protein and carry-over during the affinity purification process, which may lead to unwanted signals in the final MS analysis and a reduction in sensitivity. In this study, carry-over of protein and low-molecular weight substances has been investigated systematically and cleaning strategies are presented. Furthermore, it is demonstrated that by the introduction of colloidal particles as a capturing and transporting agent, the recovery yield of the affinity-purified ligand could be improved nearly twofold.

  • 44.
    Larseriksdotter, Helén
    et al.
    Mälardalen University, Department of Biology and Chemical Engineering.
    Oscarsson, S
    Mälardalen University, Department of Biology and Chemical Engineering.
    Buijs, J
    Biacore AB, Sweden.
    Structure Stability and Orientation of BSA Adsorbed to Silica2005In: Journal of Colloid and Interface Science, ISSN 0021-9797, Vol. 289, no 1, p. 26-35Article in journal (Other (popular science, discussion, etc.))
    Abstract [en]

    In this investigation, the structure, stability, and orientation of bovine serum albumin (BSA) adsorbed onto silica particles were studied using differential scanning calorimetry (DSC) and limited proteolysis in combination with mass spectrometry (MS). DSC gave information on the overall structural stability of BSA while limited proteolysis was used to probe the accessibility of enzymatic cleavage sites, thereby yielding information on the orientation and structure of BSA adsorbed to silica surfaces. Thermal investigation of BSA in various buffers, both free in solution and in the adsorbed state, showed that solutes that surround the protein played an important role with respect to the overall structural stability and the structural heterogeneity of BSA. Limited proteolysis with trypsin and chymotrypsin indicated that BSA in the adsorbed state is oriented with domain 2 facing the silica surface. Also, upon adsorption, no additional cleavage sites were exposed. The combination of the results presented in this study implied that BSA molecules adsorbed onto silica particles were significantly reduced in their structural stability, but not to an extent that internal residues within the nativP structure became fully exposed to the solution.

  • 45.
    Ledung, Erika
    et al.
    Mälardalen University, Department of Biology and Chemical Engineering.
    Eriksson, Per-Olov
    Mälardalen University, Department of Biology and Chemical Engineering.
    Oscarsson, Sven
    Mälardalen University, Department of Biology and Chemical Engineering.
    A strategic crossflow filtration methodology for the initial purification of promegapoietin from inclusion bodies2009In: Journal of Biotechnology, ISSN 0168-1656, E-ISSN 1873-4863, Vol. 141, no 1-2, p. 64-72Article in journal (Refereed)
    Abstract [en]

    A novel crossflow filtration methodology is demonstrated for the initial purification of the therapeutic protein, promegapoietin-1a (PMP), produced as inclusion bodies (IBs) in a recombinant Escherichia coli bioprocess. Two strategic separation steps were performed by utilizing a filtration unit with a 1000 kDa polyethersulphone membrane. The first step, aiming for separation of soluble contaminants, resulted in a 50% reduction of the host cell proteins, quantified by total amino acid analysis and a 70% reduction of all DNA, quantified by fluorometry, when washing the particulate material with a 10 mM EDTA in 50 mM phosphate buffer, pH 8. The second step, aiming for separation of particulate contaminants from solubilized IBs, resulted in a 97-99.5% reduction of endotoxin, used as a marker for cell debris, and was quantified by the kinetic turbidimetric LAL endotoxin assay. The overall PMP yield was 58% and 33% respectively for the two solubilizations investigated, guanidine hydrochloride and arginine, as measured by RP-HPLC. The scope was also to investigate the physical characteristics of the intermediate product/s with regard to the choice of 113 solvent. Preliminary results from circular dichroism spectroscopy measurements indicate that the protein secondary structure was restored when arginine was used in the second step.

  • 46.
    Lindholm, Tobias
    Mälardalen University, Department of Biology and Chemical Engineering.
    Energioptimering för Recip Strängnäs AB2008Independent thesis Advanced level (degree of Magister), 20 points / 30 hpStudent thesis
    Abstract [sv]

    Recip Strängnäs AB är ett miljöcertifierat företag som framställer och förpackar penicillin produkter. Företaget måste göra vissa reparationer på ett av ventilationssystemen. De tar tillfället i akt att gå igenom energiomsättningen i helhet då åtgärder redan måste göras. På grund av det ökade oljepriset och mer fokus på miljön är det intressant att byta ut denna energikälla som används idag, vilket är ånga som produceras genom eldning av olja. Den energikälla som är tänkt att ersätta ångan är fjärrvärme.

    Flera processer som företaget använder sig av kräver ånga, men beräkningar visar att det bara behövs ca 400 MWh/år för att driva dessa processer. Då den totala energiomsättningen för Recip Strängnäs AB är kring 3100 MWh/år skulle det preliminärt innebära en besparing på 120 000 kr/år för att gå över till att använda fjärrvärme där det är möjligt istället för ånga.

    Det hygienvatten som används på Recip Strängnäs AB kostar i dagsläget ca 76 000 kr/år att värma. En övergång till fjärrvärme skulle sänka den kostnaden till ca 66 000 kr/år. Tanken är dock att använda sig av båda kondensatvattnet, som samlas upp i kondensattanken, och den spillvärme som produceras av värmeväxlaren för ånga, destillationen och kompressorerna till att förvärma hygienvattnet. I denna rapport presenteras två alternativ på hur det kan lösas.

    Även drifttiderna för de större fläktarna har setts över. Genom att ställa ner dem till mer anpassade tider kan elkostnaderna minskas med kring 87 000kr/år.

    Det finns ytterligare möjligheter att sänka kostnaderna. Det är bland annat genom att ställa om kylkompressorn så att den använder mindre vatten och istället höjer temperaturen på det vatten som släpps ut. Det är möjligt att ställa dem på så vis att det går att använda det varma vattnet för uppvärmning av vissa processer. Den fungerar då som en värmepump.

    Vid drageringen finns det ett utgående flöde av varmluft på drygt 40ºC som inte används till något. Genom att installera en värmepump mellan utgående och ingående lufttrumma är det möjligt att minska energiförbrukningen för drageringen med ca 50 %. Det visade sig dock att installationskostnaderna blev högre än priset på den sparade energin.

  • 47.
    Neumuller, Magnus
    et al.
    Mälardalen University, Department of Biology and Chemical Engineering.
    Nilsson, Kenneth
    Uppsala Univ, Sweden.
    Pahlson, Carl
    Uppsala Univ, Sweden.
    Trypanosoma spp. in Swedish game animals2012In: Parasitology Research, ISSN 0932-0113, E-ISSN 1432-1955, Vol. 110, no 1, p. 135-139Article in journal (Refereed)
    Abstract [en]

    Serum and blood samples from 36 game animals, shot during the hunting seasons 2007-2009, were collected and analyzed for the presence of Trypanosoma spp. by three methods: isolation, polymerase chain reaction (PCR), and serology. Only fissiped animals were included, four different ruminants and wild boar. Trypanosomes could be isolated from two of the animals, and eight had detectable parasite DNA. Seven animals had high titers of anti-trypanosoma IgG antibodies. The two isolated strains, one from roe dear and one from European elk, were determined to Trypanosoma theileri by partial DNA sequencing of the 18S ribosomal gene. In the seven boars, no Trypanosoma were detected, but four out of seven strongly positive serological samples came from this group. This is the first study in Scandinavia on the presence of Trypanosoma in game animals. The results indicate that trypanosomiasis is frequently occurring among Swedish game animals.

  • 48.
    Nevalainen, Nina
    Mälardalen University, Department of Biology and Chemical Engineering.
    Effects of glial cell line-derived neurotrophic factor (GDNF) on mouse fetal ventral mesencephalic tissue2008Independent thesis Advanced level (degree of Magister), 20 points / 30 hpStudent thesis
    Abstract [en]

    The symptoms of Parkinson's disease occur due to degeneration of dopamine neurons in substantia nigra. It has been demonstrated that glial cell line-derived neurotrophic factor (GDNF) is a potent neurotrophic factor when it comes to protect and enhance survival of dopamine neurons in animal models of Parkinson's disease. The aim of this study was to evaluate short- and long-term effects of GDNF on survival and nerve fiber outgrowth of dopamine cells and astrocytic migration in mouse fetal ventral mesencephalic (VM) tissue. Primary tissue cultures were made of mouse fetal VM tissue and evaluated at 7 and 21 days in vitro (DIV) in terms of dopaminergic nerve fiber outgrowth and astrocytic migration when developed with GDNF present, partially, or completely absent. The results revealed that VM tissue cultured in the absence of GDNF did not exhibit any significant differences in migration of astrocytes or dopaminergic nerve fiber outgrowth neither after 7 DIV nor after 21 DIV, when compared with tissue cultured with GDNF present. Migration of astrocytes and dopaminergic nerve fiber outgrowth reached longer distances when tissue was left to develop for 21 DIV in comparison with 7 DIV. In order to study the long-term effects of GDNF, mouse fetal dopaminergic tissue was transplanted into the ventricles of adult mice and evaluated after 6 months. No surviving dopamine neurons were present in the absence of GDNF. In contrast dopamine neurons developed with GDNF did survive, indicating that GDNF is an essential neurotrophic factor when it comes to long-term dopamine cell survival. More cases have to be assessed in the future in order to strengthen the findings. Thus, transplanted dopamine neurons will be assessed after 3 and 12 months in order to map out when dopamine neurons deprived of GDNF undergo degeneration.

  • 49.
    Nilson, K.
    et al.
    Uppsala Univ.
    Ahlund, J.
    Uppsala Univ.
    Shariati, M. -N
    Uppsala Univ.
    Schiessling, J.
    Lund Univ.
    Palmgren, P.
    KTH.
    Brena, B.
    Uppsala Univ.
    Göthelid, E.
    Mälardalen University, Department of Biology and Chemical Engineering.
    Hennies, F.
    Lund Univ.
    Huismans, Y.
    Univ Groningen.
    Evangelista, F.
    Univ Groningen.
    Rudolf, P.
    Univ Groningen.
    Gothelid, M.
    KTH.
    Martensson, N.
    Uppsala Univ.
    Puglia, C.
    Uppsala Univ.
    Potassium-intercalated H2Pc films: Alkali-induced electronic and geometrical modifications2012In: Journal of Chemical Physics, ISSN 0021-9606, E-ISSN 1089-7690, Vol. 137, no 4, p. 044708-Article in journal (Refereed)
    Abstract [en]

    X-ray spectroscopy studies of potassium intercalated metal-free phthalocyanine multilayers adsorbed on Al(110) have been undertaken. Photoelectron spectroscopy measurements show the presence of several charge states of the molecules upon K intercalation, due to a charge transfer from the alkali. In addition, the comparison of valence band photoemission spectra with the density functional theory calculations of the density of states of the H2Pc- anion indicates a filling of the formerly lowest unoccupied molecular orbital by charge transfer from the alkali. This is further confirmed by x-ray absorption spectroscopy (XAS) studies, which show a decreased density of unoccupied states. XAS measurements in different experimental geometries reveal that the molecules in the pristine film are standing upright on the surface or are only slightly tilted away from the surface normal but upon K intercalation, the molecular orientation is changed in that the tilt angle of the molecules increases. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4738755]

  • 50.
    Nilson, Katharina
    et al.
    Uppsala Univ.
    Ahlund, John
    Uppsala Univ.
    Shariati, Masumeh-Nina
    Uppsala Univ.
    Göthelid, Emmanuelle
    Mälardalen University, Department of Biology and Chemical Engineering.
    Palmgren, Pal
    Uppsala Univ.
    Schiessling, Joachim
    Lund Univ.
    Berner, Simon
    Uppsala Univ.
    Mårtensson, Nils
    Uppsala Univ.
    Puglia, Carla
    Uppsala Univ.
    Rubidium Doped Metal-Free Phthalocyanine Monolayer Structures on Au(111)2010In: The Journal of Physical Chemistry C, ISSN 1932-7447, E-ISSN 1932-7455, Vol. 114, no 28, p. 12166-12172Article in journal (Refereed)
    Abstract [en]

    Scanning tunneling microscopy (STM) studies of monolayer of metal-free phthalocyanine (H(2)Pc) adsorbed on Au(111) have shown ordered arrangement of the molecules on the surface. Evaporation of H2Pc onto the Au(111) surface and post annealing of the sample to 670 K results in a densely packed structure of the molecules. The monolayer is characterized by molecules adsorbed with the molecular plane parallel to the substrate surface in a square adsorption unit cell. Furthermore, the high resolution images revealed the orientation of individual molecules. The H(2)Pc/Au(111) system has also been doped by rubidum and compared to the undoped layers. The Rb affects the molecular adsorption geometry, and a hexagonal unit cell is found for the coadsorption of H(2)Pc and Rb. Upon doping, highly ordered Rb-induced protrusions are observed at the benzene site of adsorbed molecules.

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