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  • 201.
    Barghi, Hamidreza
    et al.
    Högskolan i Borås, Institutionen Ingenjörshögskolan.
    Skrifvars, Mikael
    Högskolan i Borås, Institutionen Ingenjörshögskolan.
    Taherzadeh, Mohammad J.
    Högskolan i Borås, Institutionen Ingenjörshögskolan.
    Synthesis and characterization of novel bulk hydrophilic acetaldehyde modified polyamide 462011Konferensbidrag (Övrigt vetenskapligt)
  • 202. Barig, Susann
    et al.
    Alisch, Romy
    Nieland, Susanne
    Wuttke, Anne
    Graeser, Yvonne
    Huddar, Mahesh
    Schnitzlein, Klaus
    Stahmann, Klaus-Peter
    Monoseptic growth of fungal lipase producers under minimized sterile conditions: Cultivation of Phialemonium curvatum in 350 L scale2011Ingår i: Engineering in Life Sciences, ISSN 1618-0240, E-ISSN 1618-2863, Vol. 11, nr 4, s. 387-394Artikel i tidskrift (Refereegranskat)
  • 203.
    Barkenäs, Emelie
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för biologisk grundutbildning.
    Automation of a solid-phase proximity ligation assay for biodefense applications2013Självständigt arbete på avancerad nivå (yrkesexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [en]

    The extent of devastation caused by a biological warfare attack is highly correlated to the time from release to detection. As a step towards lowering the detection time the international project TWOBIAS was launched. Here, the main goal is to develop an automated, specific and sensitive combined detection and identification instrument capable of identifying a biological threat within an hour. The identification unit is comprised of a sample preparation module, an amplification module and a detection module and utilizes a proximity ligation assay in combination with circle-to-circle amplification in order to detect a biological threat. This thesis describes the automation of the sample preparation steps of the assay and the integration with the downstream units. The functionality of the sample preparation module was verified by subjecting it to biological samples in a laboratory and at a real-life location. The results showed that the sample preparation module was capable of preparing a sample collected in a complex environment with the same results as a sample prepared in a laboratory. 

  • 204.
    Barzegar, Hamid Reza
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för fysik. Department of Physics, University of California, Berkeley, CA 94720, USA; Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA; Kavli Energy NanoSciences Institute at the University of California, Berkeley and the Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA.
    Yan, Aiming
    Coh, Sinisa
    Gracia-Espino, Eduardo
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för fysik.
    Ojeda-Aristizabal, Claudia
    Dunn, Gabriel
    Cohen, Marvin L.
    Louie, Steven G.
    Wågberg, Thomas
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för fysik.
    Zettl, Alex
    Spontaneous twisting of a collapsed carbon nanotube2017Ingår i: Nano Reseach, ISSN 1998-0124, E-ISSN 1998-0000, Vol. 10, nr 6, s. 1942-1949Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We study the collapsing and subsequent spontaneous twisting of a carbon nanotube by in situ transmission electron microscopy (TEM). A custom-sized nanotube is first created in the microscope by selectively extracting shells from a parent multi-walled tube. The few-walled, large-diameter daughter nanotube is driven to collapse via mechanical stimulation, after which the ribbon-like collapsed tube spontaneously twists along its long axis. In situ diffraction experiments fully characterize the uncollapsed and collapsed tubes. The experimental observations and associated theoretical analysis indicate that the origin of the twisting is compressive strain.

  • 205.
    Basselet, Pascal
    et al.
    KTH, Skolan för bioteknologi (BIO), Bioprocessteknik.
    Wegrzyn, Grzegorz
    Enfors, Sven-Olof
    KTH, Skolan för bioteknologi (BIO), Bioprocessteknik.
    Gabig-Ciminska, Magdalena
    KTH, Skolan för bioteknologi (BIO), Bioprocessteknik.
    Sample processing for DNA chip array-based analysis of enterohemorrhagic Escherichia coli (EHEC)2008Ingår i: Microbial Cell Factories, ISSN 1475-2859, E-ISSN 1475-2859, Vol. 7Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Background: Exploitation of DNA-based analyses of microbial pathogens, and especially simultaneous typing of several virulence-related genes in bacteria is becoming an important objective of public health these days. Results: A procedure for sample processing for a confirmative analysis of enterohemorrhagic Escherichia coli (EHEC) on a single colony with DNA chip array was developed and is reported here. The protocol includes application of fragmented genomic DNA from ultrasonicated colonies. The sample processing comprises first 2.5 min of ultrasonic treatment, DNA extraction (2x), and afterwards additional 5 min ultrasonication. Thus, the total sample preparation time for a confirmative analysis of EHEC is nearly 10 min. Additionally, bioinformatic revisions were performed in order to design PCR primers and array probes specific to most conservative regions of the EHEC-associated genes. Six strains with distinct pathogenic properties were selected for this study. At last, the EHEC chip array for a parallel and simultaneous detection of genes etpC-stx1-stx2-eae was designed and examined. This should permit to sense all currently accessible variants of the selected sequences in EHEC types and subtypes. Conclusion: In order to implement the DNA chip array-based analysis for direct EHEC detection the sample processing was established in course of this work. However, this sample preparation mode may also be applied to other types of EHEC DNA-based sensing systems.

  • 206.
    Basu, Alex
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för biologisk grundutbildning.
    Relation between hydrogen production and photosynthesis in the green algae Chlamydomonas reinhardtii2015Självständigt arbete på avancerad nivå (yrkesexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [en]

    The modernized world is over-consuming low-cost energy sources that strongly contributes to pollution and environmental stress. As a consequence, the interest for environmentally friendly alternatives has increased immensely. One such alternative is the use of solar energy and water as a raw material to produce biohydrogen through the process of photosynthetic water splitting. In this work, the relation between H2-production and photosynthesis in the green algae Chlamydomonas reinhardtii was studied with respect to three main aspects: the establishment of prolonged H2-production, the involvement of PSII in H2-production and the electron pathways associated with PSII during H2-production. For the first time, this work reveals that PSII plays a crucial role throughout the H2-producing phase in sulfur deprived C. reinhardtii. It further reveals that a wave-like fluorescence decay kinetic, before only seen in cyanobacteria, is observable during the H2-producing phase in sulfur deprived C. reinhardtii, reflecting the presence of cyclic electron flows also in green algae. 

  • 207.
    Bauer, Fredric
    et al.
    Lund University.
    Berglund, Kris
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Hulteberg, Christian
    Lund University.
    Lundgren, Joakim
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Mesfun, Sennai
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Nilsson, Robert
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Rova, Ulrika
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Wännström, Sune
    SP Technical Research Institute of Sweden.
    Comparative system analysis of carbon preserving fermentations for biofuels production2013Rapport (Refereegranskat)
  • 208.
    Baumann, Martin J.
    et al.
    KTH, Skolan för bioteknologi (BIO).
    Eklöf, Jens
    KTH, Skolan för bioteknologi (BIO).
    Michel, G.
    Kallas, Åsa
    KTH.
    Teeri, Tuula
    KTH, Skolan för bioteknologi (BIO).
    Czjzek, Mirjam
    KTH.
    Brumer, Harry
    KTH, Skolan för bioteknologi (BIO), Glykovetenskap.
    Structural analysis of nasturtium NXG reveals the evolution of GH16 xyloglucanase activity from XETs: biological implications for cell wall metabolismManuskript (Övrigt vetenskapligt)
  • 209.
    Bayat, Narges
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för biokemi och biofysik.
    Lopes, Viviana R.
    Schoelermann, Julia
    Dahl Jensen, Lasse
    Cristobal, Susana
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för biokemi och biofysik.
    Vascular toxicity of ultra-small TiO2 nanoparticles and single walled carbon nanotubes in vitro and in vivo2015Ingår i: Biomaterials, ISSN 0142-9612, E-ISSN 1878-5905, Vol. 63, s. 1-13Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Ultra-small nanoparticles (USNPs) at 1-3 nm are a subset of nanoparticles (NPs) that exhibit intermediate physicochemical properties between molecular dispersions and larger NPs. Despite interest in their utilization in applications such as theranostics, limited data about their toxicity exist. Here the effect of TiO2-USNPs on endothelial cells in vitro, and zebrafish embryos in vivo, was studied and compared to larger TiO2-NPs (30 nm) and to single walled carbon nanotubes (SWCNTs). In vitro exposure showed that TiO2-USNPs were neither cytotoxic, nor had oxidative ability, nevertheless were genotoxic. In vivo experiment in early developing zebrafish embryos in water at high concentrations of TiO2-USNPs caused mortality possibly by acidifying the water and caused malformations in the form of pericardial edema when injected. Myo1C involved in glomerular development of zebrafish embryos was upregulated in embryos exposed to TiO2-USNPs. They also exhibited anti-angiogenic effects both in vitro and in vivo plus decreased nitric oxide concentration. The larger TiO2-NPs were genotoxic but not cytotoxic. SWCNTs were cytotoxic in vitro and had the highest oxidative ability. Neither of these NPs had significant effects in vivo. To our knowledge this is the first study evaluating the effects of TiO2-USNPs on vascular toxicity in vitro and in vivo and this strategy could unravel USNPs potential applications.

  • 210. Beatriz Badia, Mariana
    et al.
    Mans, Robert
    Lis, Alicia V.
    Ariel Tronconi, Marcos
    Lucia Arias, Cintia
    Maurino, Veronica Graciela
    Santiago Andreo, Carlos
    Fabiana Drincovich, Maria
    van Maris, Antonius J. A.
    KTH, Skolan för bioteknologi (BIO), Industriell bioteknologi.
    Gerrard Wheeler, Mariel Claudia
    Specific Arabidopsis thaliana malic enzyme isoforms can provide anaplerotic pyruvate carboxylation function in Saccharomyces cerevisiae2017Ingår i: The FEBS Journal, ISSN 1742-464X, E-ISSN 1742-4658, Vol. 284, nr 4, s. 654-665Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    NAD(P)-malic enzyme (NAD(P)-ME) catalyzes the reversible oxidative decarboxylation of malate to pyruvate, CO2, and NAD(P)H and is present as a multigene family in Arabidopsis thaliana. The carboxylation reaction catalyzed by purified recombinant Arabidopsis NADP-ME proteins is faster than those reported for other animal or plant isoforms. In contrast, no carboxylation activity could be detected in vitro for the NAD-dependent counterparts. In order to further investigate their putative carboxylating role in vivo, Arabidopsis NAD(P)-ME isoforms, as well as the NADP-ME2del2 (with a decreased ability to carboxylate pyruvate) and NADP-ME2R115A (lacking fumarate activation) versions, were functionally expressed in the cytosol of pyruvate carboxylase-negative (Pyc(-)) Saccharomyces cerevisiae strains. The heterologous expression of NADP-ME1, NADP-ME2 (and its mutant proteins), and NADP-ME3 restored the growth of Pyc(-) S. cerevisiae on glucose, and this capacity was dependent on the availability of CO2. On the other hand, NADP-ME4, NAD-ME1, and NAD-ME2 could not rescue the Pyc(-) strains from C-4 auxotrophy. NADP-ME carboxylation activity could be measured in leaf crude extracts of knockout and over-expressing Arabidopsis lines with modified levels of NADP-ME, where this activity was correlated with the amount of NADP-ME2 transcript. These results indicate that specific A. thaliana NADP-ME isoforms are able to play an anaplerotic role in vivo and provide a basis for the study on the carboxylating activity of NADP-ME, which may contribute to the synthesis of C-4 compounds and redox shuttling in plant cells.

  • 211.
    Beaussant Törne, Karin
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Materialfysik, MF.
    Investigation of corrosion properties of metals for degradable implant applications2017Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [sv]

    Nedbrytbara metaller utgör en ny klass av biomaterial med potential attersätta permanenta material i tillfälliga applikationer. Detta för att minskarisken för långvariga biverkningar. I den pågående forskningen för att utvecklanya nedbrytbara metaller är screening av nya material genom in vitro testmetoderett attraktivt alternativ för att undvika onödiga, tidskrävande ochdyrbara djurstudier.Denna avhandling fokuserar på in vitro-testning av zink- och magnesiumbaserademetaller. Inverkan av faktorer såsom sammansättningen av testlösningen,buffersystemet, belastning samt mikrostruktur hos legeringar undersöktes.Genom att använda elektrokemiska in situ tekniker såsom impedansspektroskopi(EIS) är det möjligt att studera gränssnittet mellan metall ochlösning och karakterisera egenskaperna hos den korroderande ytan. Ex situytkaraktäriseringstekniker som svepelektronmikroskopi och infraröd spektroskopianvändes sedan för att komplettera resultaten av de elektrokemiskamätningarna.Korrosionen av zink i Ringer’s lösning fanns vara närmare in vivo korrosionän korrosionen i fosfatbuffrad saltlösning (PBS). Ringers lösning är därför denföredragna testmiljön för långsiktig utvärdering av zinkbaserade metallerDet biologiska buffersystemet (CO2/H2CO3) bör företrädesvis användasför att stabilisera pH-värdet på testlösningen vid magnesiumnedbrytning. NärHEPES användes för att stabilisera pH ökade korrosionshastigheten på grundav bildning av mindre skyddande skikt av korrosionsproduktMöjligheten att använda helblod och plasma som mer kliniskt relevantatestmiljöer utvärderades och befanns producera reproducerbara resultat.Bildning av ett korrosionsskikt bestående av både organiskt och oorganisktmaterial detekterades på zink i både plasma och helblod.När zink prover i helbod utsattes för belastning förhindrade korrosionsskiktetbildningen av mikrosprickor och förtidigt brott av provet. Det varvidare möjligt att detektera tidig sprickbildning på grund av belastning avMagnesium AZ61-legering med EIS.Adsorption av organiska species på zinkytan under anodisk polariseringökar yttäckningen av Zn-joner i helblod. Den ökade yttäckningen leder sedantill utfällningen av ett skyddande skikt av zinkfosfater och en minskadkorrosionshastighet vid högre potentialer.Korrosion av Zn-Mg och Zn-Ag legeringar i Ringers lösning befanns skevia selektiv upplösning. Lokal utfällning av korrosionsprodukter och bildningav ett poröst, mindre skyddande skikt av korrosionsprodukter hittades påZn-Mg legeringar. Den selektiva upplösningen av Zn-Ag legering orsakade enanrikning av AgZn3 vilket kan påverka biokompatibiliteten av ett implantatmed tiden.

  • 212. Beerenwinkel, N.
    et al.
    Greenman, C. D.
    Lagergren, Jens
    KTH, Skolan för datavetenskap och kommunikation (CSC), Beräkningsvetenskap och beräkningsteknik (CST).
    Computational Cancer Biology: An Evolutionary Perspective2016Ingår i: PloS Computational Biology, ISSN 1553-734X, E-ISSN 1553-7358, Vol. 12, nr 2, artikel-id e1004717Artikel i tidskrift (Refereegranskat)
  • 213.
    Behravan, Gity
    et al.
    Umeå universitet.
    Sen, Srikanta
    Stockholms Universitet.
    Rova, Ulrika
    Thelander, Lars
    Umeå universitet.
    Eckstein, Fritz
    Max-Planck-Institut fur Experimentelle Medizin.
    Gräslund, Astrid
    Stockholms Universitet.
    Formation of a free radical of the sulfenylimine type in the mouse ribonucleotide reductase reaction with 2'-azido-2'-deoxycytidine 5'-diphosphate1995Ingår i: Biochimica et Biophysica Acta, Gene Structure and Expression, ISSN 0167-4781, E-ISSN 1879-2634, Vol. 1264, nr 3, s. 323-329Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Mouse and Escherichia coli ribonucleotide reductases (RR) both belong to the same class of RR, where the enzyme consists of two non-identical subunits, proteins R1 and R2. A transient free radical was observed by EPR spectroscopy in the mouse RR reaction with the suicidal inhibitor 2′-azido-2′-deoxycytidine 5′-diphosphate. The detailed hyperfine structure of the EPR spectrum of the transient radical is somewhat different for the mouse and previously studied E. coli enzymes. When the positive allosteric effector ATP was replaced by the negative effector dATP, no transient radical was observed, showing that ‘normal' binding of the inhibitor to the substrate binding site is required. Using the mouse protein R2 mutants W 103Y and D266A, where the mutations have been shown to specifically block long range electron transfer between the active site of the R1 protein to the iron/radical site in protein R2, no evidence of transient radical was found. Taken together, the data suggest that the radical is located at the active site in protein R1, and is probably of the sulfenylimine type

  • 214. Beigi, H.M.
    et al.
    Karimi, Keikhosro
    Högskolan i Borås, Institutionen Ingenjörshögskolan.
    Effects of temperature, pH and glucose concentration on bioethanol production by Mucor indicus2009Konferensbidrag (Övrigt vetenskapligt)
  • 215.
    Beijer, Ronja
    Linköpings universitet, Institutionen för fysik, kemi och biologi.
    Enzymatic treatement of wastewater sludge in presence of a cation binding agent: improved solubilisation and increased methane production2008Självständigt arbete på grundnivå (yrkesexamen), 20 poäng / 30 hpStudentuppsats
    Abstract [en]

    Stockholm Water is a water and sewage company with Henriksdal as one of two wastewater treatment plants (WWTPs). At Henriksdal wastewater sludge generated in the wastewater treatment process is digested which generate biogas; a mixture of mainly methane and carbon dioxide. If purified to methane content of 96 - 98 % this gas is called biomethane.

    Biogasmax is a project aiming to reduce the use of fossile fuels in Europe by providing that biogas is a good technical, economical and environmental alternative as vehicle fuel. The specific aim for Stockholm Water is to increase the biogas production at the existing plant in Henriksdal. Enzymatic treatment of wastewater sludge is an innovative technique earlier proofed to increase the biogas production from wastewater sludge with up to 60 %. The enzyme activity is in turn proven to significantly increase in the presence of a cation binding agent.

    One aim with this thesis was to investigate if the sludge from Henriksdal wastewater treatment process at all is affected of enzymatic treatment in presence of a cation binding agent since this has shown to have some significance. The chemical oxygen demand (COD) was measured in the liquid phase of sludge after treatment and used as a measurement of treatment effect. Another aim of this thesis was to look into the possibility to increase the methane production from sludge at Henriksdal WWTP. This was investigated through batch laboratory digestion tests.

    The sludge from Henriksdal WWTP was shown to be a good substrate for the enzymes added. COD in the liquid phase was increased with 17 – 32 % depending on the dose of enzymes and sodium citrate added. Digestion of sludge with a total addition of 18.6 mg enzymes per 1 g total solids (TS) and a concentration of 5 mM sodium citrate increased the methane production with almost 18 % compared to untreated sludge. This equals an increase of 18.3 % when converted to represent a totally blended and continuous digestion chamber at Henriksdal WWTP. The increased methane production also results in a sludge reduction out from the digestion chambers. The increased methane production and sludge reduction though does not fulfil the increased costs for the enzymes and sodium citrate applied. These doses must be decreased and the costs for both enzymes and sodium citrate must be reduced for this technique to be economically feasible in a full scale operation.

  • 216.
    Bekin, Seda
    et al.
    Department of Chemical Engineering, Faculty of Engineering, Istanbul University.
    Sarmad, Shokat
    Department of Chemical Engineering, Faculty of Engineering, Istanbul University.
    Gürkan, Koray
    Department of Electrical and Electronics Engineering, Faculty of Engineering, Istanbul University.
    Keçeli, Gönül
    Department of Chemistry, Faculty of Engineering, Istanbul University.
    Gürdağ, Gülten
    Department of Chemical Engineering, Faculty of Engineering, Istanbul University.
    Synthesis, characterization and bending behavior of electroresponsive sodium alginate / poly (acrylic acid) interpenetrating network films in an electric stimulus2014Ingår i: Sensors and actuators. B, Chemical, ISSN 0925-4005, E-ISSN 1873-3077, Vol. 202, s. 878-892Artikel i tidskrift (Refereegranskat)
  • 217.
    Bekin, Seda
    et al.
    Department of Chemical Engineering, Faculty of Engineering, Istanbul University.
    Sarmad, Shokat
    Department of Chemical Engineering, Faculty of Engineering, Istanbul University.
    Gürkan, Koray
    Department of Electrical and Electronics Engineering, Faculty of Engineering, Istanbul University.
    Yenici, Gökcen
    Department of Chemical Engineering, Faculty of Engineering, Istanbul University, Avcilar.
    Keceli, Gönül
    Department of Chemistry, Faculty of Engineering, Istanbul University.
    Gürdag, Gülten
    Department of Chemical Engineering, Faculty of Engineering, Istanbul University.
    Dielectric, thermal, and swelling properties of calcium ion crosslinked sodium alginate film2014Ingår i: Polymer Engineering and Science, ISSN 0032-3888, E-ISSN 1548-2634, Vol. 54, nr 6, s. 1372-1382Artikel i tidskrift (Refereegranskat)
  • 218.
    Benevides, Kristina
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för biologisk grundutbildning.
    Broström, Oscar
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för biologisk grundutbildning.
    Elison Kalman, Grim
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för biologisk grundutbildning.
    Swenson, Hugo
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för biologisk grundutbildning.
    Vlassov, Andrei
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för biologisk grundutbildning.
    Ågren, Josefin
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för biologisk grundutbildning.
    Stabil och antibiotikafri läkemedelsproduktion i rekombinant Escherichia coli2017Självständigt arbete på grundnivå (kandidatexamen), 10 poäng / 15 hpStudentuppsats (Examensarbete)
    Abstract [sv]

    Den här rapporten presenterar ett antibiotikafritt, stabilt och kromosombaserat expressionssystem för läkemedelsproduktion i Escherichia coli på beställning av företaget Affibody AB. E. coli-stammen BL21(DE3) valdes som värdorganism för expressionssystemet. Systemet består av en genkassett som innehåller en T7-promotor, en 5′-UTR från genen ompA och en terminatorsekvens från RNA-operonet rrnB. Fyra kopior av genkassetten ska integreras i pseudogenerna caiB, yjjM, hsdS och yjiV. En datormodell som modellerar det egentliga kopietalet i cellerna har skapats i mjukvaran MATLAB, vilket visar att det uppskattas vara maximalt 32 kopior av genkassetten per cell på grund av replikation av kromosomen. Ett högt pH i fermentorn; att använda fed-batch och blandade kolhydratkällor; och att använda stammen BL21(DE3) minskar acetatproduktionen i cellen. En lägre acetatproduktion kan leda till en högre produkthalt. En proteinutbytesmodell för mjukvaran MATLAB har konstruerats för att uppskatta koncentrationen av Affibody®-molekylen i en E. coli cell.

  • 219.
    Bengtsson, Katarina
    Linköpings universitet, Institutionen för fysik, kemi och biologi. Linköpings universitet, Tekniska högskolan.
    Design of a galvanotaxic track for cells, using polymer electrodes.2011Självständigt arbete på avancerad nivå (masterexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [en]

    Galvanotaxis is the movement of cells in an applied electric field. The first steps to design a chip for observations of galvanotaxic behavior of cells were done in this work. The chip is a miniaturised system of previous larger galvanotaxis systems and uses materials which are thought to be biocompatible. The system was constructed on microscope slides with a channel in PDMS with adjacent polymer electrodes. The polymer electrodes were made from poly(3,4-ethylenedioxythiophene) poly(styrenesulfonate) (PEDOT:PSS), glycerol and Silquest A-187. The PEDOT:PSS electrodes were connected with either an evaporated metal electrode of titanium and gold or a gold net. Systems with PEDOT:PSS are neutralised when put in excessive amount of PBS (pH=7.4) for 24 hours. The final system had a channel with dimension length=14 mm, width=0.5 mm and height=0.25 mm. PEDOT:PSS worked as an electrode material and the achieved electric field through the channel was between 55 V/m and 160 V/m with an applied voltage of 1 V. The decrease of the electric field within the first hour was between 10 % and 30%.  Further development of this system could give an easy way to observe galvanotaxic behaviour of cells or an instrument that can distinguish between different cell types.

  • 220.
    Bengtsson, Magnus
    et al.
    Norwegian University of Science and Technology (NTNU), Trondheim.
    Gatenholm, Paul
    CTH.
    Oksman, Kristiina
    The effect of crosslinking on the properties of polyethylene/wood flour composites2005Ingår i: Composites Science And Technology, ISSN 0266-3538, E-ISSN 1879-1050, Vol. 65, nr 10, s. 1468-1479Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In this study, the possibility of using silane technology in crosslinking composites of wood flour and polyethylene has been investigated. Composites of vinyltrimethoxy silane grafted high density polyethylene and wood flour were produced by compounding in a twin-screw extruder. Gel content analysis with p-xylene extraction revealed higher gel content in the samples where wood flour was added compared to neat crosslinked matrix. Mechanical analysis of the crosslinked composites showed increased tensile strength with increasing amount of wood flour, which might be an indication of improved adhesion between the matrix and the wood flour. The stiffness increased with increasing amount of wood flour with accompanied decrease in strain at break. Dynamic mechanical thermal analysis of crosslinked plastics and composites showed no significant shift in the γ-transition towards higher temperature for the composites compared to neat plastic. Short-term creep experiments showed reduced creep deformation with increasing amount of wood flour. Crosslinking of the composites reduced the creep deformation further. A boiling test in water followed by tensile testing showed that the crosslinked composites were less susceptible to water uptake compared to the non-crosslinked. Moreover, the decrease in tensile strength of the crosslinked composites was not as significant as for the non-crosslinked composites. Scanning electron microscopy revealed good compatibility and adhesion between the plastic and the wood flour for crosslinked composites.

  • 221.
    Bengtsson, Magnus
    et al.
    Norwegian University of Science and Technology (NTNU), Trondheim.
    LeBaillif, Marie
    Norwegian University of Science and Technology (NTNU), Trondheim.
    Oksman, Kristiina
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Materialvetenskap.
    Extrusion and mechanical properties of highly filled cellulose fibre-polypropylene composites2007Ingår i: Composites. Part A, Applied science and manufacturing, ISSN 1359-835X, E-ISSN 1878-5840, Vol. 38, nr 8, s. 1922-1931Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This study focused on manufacturing of highly filled cellulose fibre-polypropylene composites and evaluation of the mechanical properties of the composites. Cellulose fibre reinforced polypropylene composites with up to 60 wt-% of fibres with and without coupling agent were manufactured by extrusion. In order to achieve consistent feeding of the fibres into the extruder a pelletization technique was used where the fibres were pressed into pellets. Two commercial grades of cellulose fibres were used in the study, bleached sulfite and bleached kraft fibres. Fibre dimension measurements showed that the pelletization process and extrusion at high fibre loading caused the most severe fibre breakage. Flexural testing showed that increased fibre loading made the composites stiffer but reduced the toughness. Addition of maleic anhydride grafted coupling agent increased the stiffness and strength of the composites significantly. In general, there was no significant difference in the mechanical properties between the composites with kraft and sulfite fibres. Scanning electron microscopy showed that addition of coupling agent improved the interfacial adhesion between the fibres and polypropylene matrix.

  • 222.
    Bengtsson, Magnus
    et al.
    Norwegian University of Science and Technology (NTNU), Trondheim.
    Oksman, Kristiina
    Crosslinked wood-thermoplastic composites: profile extrusion & mechanical properties2006Ingår i: Proceedings of the International Conference on Progress in Wood and Bio-Fibre Plastic Composites, Centre for Materials and Manufacturing , 2006Konferensbidrag (Refereegranskat)
  • 223. Bengtsson, Magnus
    et al.
    Oksman, Kristiina
    Optimization of silane crosslinkling technology for use in polyethylene-wood flour composites2005Ingår i: 8th International Conference on Woodfiber-Plastic Composites (and Other Natural Fibers): May 23 - 25, 2005, Monona Terrace Community & Convention Center, Madison, Wisconsin, USA, Forest Products Society, 2005Konferensbidrag (Refereegranskat)
  • 224.
    Bengtsson, Magnus
    et al.
    Norwegian University of Science and Technology (NTNU), Trondheim.
    Oksman, Kristiina
    Silane crosslinked wood plastic composites: Processing and properties2006Ingår i: Composites Science And Technology, ISSN 0266-3538, E-ISSN 1879-1050, Vol. 66, nr 13, s. 2177-2186Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The focus of the study has been to produce silane crosslinked wood plastic composites in a compounding process. Silane crosslinking is one way to improve the mechanical and long-term properties of wood plastic composites. Silane crosslinked composites with different amounts of vinyltrimethoxy silane were produced in a compounding process using a co-rotating twin-screw extruder. The composites were stored in a sauna and at room temperature to study the effect of humidity on the degree of crosslinking. Gel content and swelling experiments showed that the highest degree of crosslinking was found in the composites stored in a sauna. The crosslinked composites showed toughness, impact strength and creep properties superior to those composites to which no silane was added. The flexural modulus, on the other hand, was lower in the crosslinked samples than in the non-crosslinked ones. Differential scanning calorimetry measurements of the composites showed a lower crystallinity in the crosslinked samples than in the non-crosslinked.

  • 225. Bengtsson, Magnus
    et al.
    Oksman, Kristiina
    The Effect of Crosslinking on the Properties of Polyethylene/Wood Flour Composites2004Ingår i: Conference proceedings: Progress in Woodfibre-Plastic Composites Conference 2004 : May 10 - 11, 2004, Toronto, Canada, Toronto, 2004Konferensbidrag (Refereegranskat)
  • 226.
    Bengtsson, Magnus
    et al.
    Norwegian University of Science and Technology (NTNU), Trondheim.
    Oksman, Kristiina
    The use of silane technology in crosslinking polyethylene/wood flour composites2006Ingår i: Composites. Part A, Applied science and manufacturing, ISSN 1359-835X, E-ISSN 1878-5840, Vol. 37, nr 5, s. 752-765Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In this study, the use of silane technology in crosslinking polyethylene-wood flour composites have been investigated. Composites were produced in a one-step process using a co-rotating twin-screw extruder. The composites were stored in a sauna and at room temperature to study the effect of humidity on the degree of crosslinking. Crosslinked composites showed improved toughness and creep properties compared to non-crosslinked composites. The flexural modulus, on the other hand, was lower in the crosslinked samples than in the non-crosslinked ones. FTIR was used to study the crosslinking reaction in the samples. X-ray mapping of the silicon signal was also performed to locate the silane in the composites. This study provides a basis for proposing, that part of the silane is grafted onto polyethylene and wood thereby creating a crosslinked network in the matrix with chemical bonds (covalent and hydrogen bonding) to wood. The other part of the silane remains un-reacted and blends into the system.

  • 227.
    Bengtsson, Magnus
    et al.
    Norwegian University of Science and Technology (NTNU), Trondheim.
    Stark, Nicole
    Forest Products Laboratory.
    Oksman, Kristiina
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Materialvetenskap.
    Durability and mechanical properties of silane cross-linkedwood thermoplastic composites2007Ingår i: Composites Science And Technology, ISSN 0266-3538, E-ISSN 1879-1050, Vol. 67, nr 13, s. 2728-2738Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In this study, silane cross-linked wood-polyethylene composite profiles were manufactured by reactive extrusion. These composites were evaluated regarding their durability and mechanical properties in comparison with two non-cross-linked wood-polyethylene composites. An addition of only 2% w/w of silane solution during manufacturing was enough to achieve almost 60% degree of cross-linking after curing. The cross-linked composites showed flexural toughness superior to the non-cross-linked composites. The cross-linked composites also absorbed less moisture during a boiling test in water and this was an indirect evidence of improved interfacial adhesion. After accelerated weathering for 1000-3000 h the general trend was a decrease in flexural modulus and strength of both the non-cross-linked and cross-linked composites. The decrease in modulus seemed to be lower for the cross-linked composites while the decrease in strength seemed to be higher compared to the non-cross-linked composites. Weathering also resulted in a considerable colour fading of the composites. Water absorption-freeze-thaw cycling decreased the flexural modulus of non-cross-linked composites considerably while there was no statistical decrease in modulus for the cross-linked composites. There was only an insignificant decrease in strength for the composites after the water absorption-freeze-thaw cycling.

  • 228.
    Bengtsson, Magnus
    et al.
    Norwegian University of Science and Technology (NTNU), Trondheim.
    Stark, Nicole
    Forest Products Laboratory.
    Oksman, Kristiina
    Profile Extrusion and Mechanical Properties of Crosslinked Wood-Thermoplastic Composites2006Ingår i: Polymer Composites, ISSN 0272-8397, E-ISSN 1548-0569, Vol. 27, nr 2, s. 184-194Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Challenges for wood-thermoplastic composites to be utilized in structural applications are to lower product weight and to improve the long-term load performance. Silane crosslinking of the composites is one way to reduce the creep during long-term loading and to improve the mechanical properties. In this study, silane crosslinked wood-polyethylene composites were produced by reactive extrusion and subsequently manufactured into rectangular profiles. The silane crosslinked composites were stored in a sauna at 90 °C to increase the degree of crosslinking. The toughness of the silane crosslinked composites was significantly higher than for the non-crosslinked composites. Improved adhesion between the wood and polyethylene phases is most likely the reason for the improved toughness of the crosslinked composites. There was no significant difference in flexural modulus between the crosslinked and non-crosslinked composites. In addition, impact testing showed that the impact strength of the crosslinked composites was considerable higher (at least double) than the non-crosslinked. The effect of temperature on the impact strength of the composites indicated slightly higher impact strength at _30 °C than at 0° and at 25 °C, and then an incrase in impact strength at 60 °C. Crosslinking also reduced the creep response during short-term loading. Moreover, scanning electron microscopy on the fracture surface of the crosslinked composites revealed good adhesion between the polyethylene and wood phases.

  • 229.
    Bergeld, Linnéa
    Karlstads universitet, Institutionen för kemi.
    Trametes versicolor laccase: random mutagenesis and heterologous expression in Pichia pastoris2008Självständigt arbete på avancerad nivå (magisterexamen), 20 poäng / 30 hpStudentuppsats
    Abstract [en]

    Laccase is a blue multi-copper oxidase. It has a broad biotechnical potential which increases the interest to study the enzyme further. A laccase-encoding gene from the white-rot fungus Trametes versicolor (lcc2) was mutated using two different methods for random mutagenesis: error-prone PCR and a method based on an E.coli strain (ES1301 mutS) that introduces random mutations. For the error-prone PCR reaction, the vector pPICZB with the lcc2 gene inserted was used as template. The E. coli strain ES1301 mutS was transformed with the vector pBluescript SKII with the lcc2 gene as insert. The mutagenesis products were cloned into the Pichia pastoris expression vector pPICZB for transformation of P. pastoris SMD1168. The transformants were spread on agar plates containing zeocin. Laccase-secreting transformants were selected by their ability to oxidize the substrates ABTS [2,2´-azinobis-(3-ethylbenzthiazoline-6-sulfonic acid)] and syringaldazine [N,N´-bis(3,5-dimethoxy-4-hydroxybenzylidene)hydrazine], the products of which give green and purple colour, respectively. Around 20 transformants from each of the mutagenesis methods were transformed to plates containing 1 mM ABTS or 1 mM syringaldazine. None of the transformants produced any colour. Control transformants (pPICZB with unmutated lcc2) were also spread on plates with either ABTS or syringaldazine. The transformants gave rise to green colour after 24 hours on the ABTS plates and to purple colour after 72 hours on the syringaldazine plates. Experimets with different chromogenic substrates indicated that ABTS and syringaldazine were best suited for screening of mutants. Remazol Brilliant Blue and Phenol Red are two substrates that after optimisation can serve as alternatives for the selection of laccase-secreting transformants.

  • 230.
    Bergenheim, Veronica
    Mälardalens högskola, Institutionen för biologi och kemiteknik.
    Effects of nicotine on GABAA subunit expression in the rat brain2007Studentuppsats
    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.

  • 231. Bergenholtz, Sa Schoug
    et al.
    Wessman, Per
    Wuttke, Anne
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för medicinsk cellbiologi.
    Håkansson, Sebastian
    A case study on stress preconditioning of a Lactobacillus strain prior to freeze-drying2012Ingår i: Cryobiology, ISSN 0011-2240, E-ISSN 1090-2392, Vol. 64, nr 3, s. 152-159Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Freeze-drying of bacterial cells with retained viability and activity after storage requires appropriate formulation, i.e. mixing of physiologically adapted cell populations with suitable protective agents, and control of the freeze-drying process. Product manufacturing may alter the clinical effects of probiotics and it is essential to identify and understand possible factor co-dependencies during manufacturing. The physical solid-state behavior of the formulation and the freeze-drying parameters are critical for bacterial survival and thus process optimization is important, independent of strain. However, the maximum yield achievable is also strain-specific and strain survival is governed by e.g. medium, cell type, physiological state, excipients used, and process. The use of preferred compatible solutes for cross-protection of Lactobacilli during industrial manufacturing may be a natural step to introduce robustness, but knowledge is lacking on how compatible solutes, such as betaine, influence formulation properties and cell survival. This study characterized betaine formulations, with and without sucrose, and tested these with the model lactic acid bacteria Lactobacillus coryniformis Si3. Betaine alone did not act as a lyo-protectant and thus betaine import prior to freeze-drying should be avoided. Differences in protective agents were analyzed by calorimetry, which proved to be a suitable tool for evaluating the characteristics of the freeze-dried end products.

  • 232.
    Berghel, Jonas
    et al.
    Karlstads universitet, Fakulteten för teknik- och naturvetenskap, Avdelningen för energi-, miljö- och byggteknik.
    Renström, Roger
    Karlstads universitet, Fakulteten för teknik- och naturvetenskap, Avdelningen för energi-, miljö- och byggteknik.
    Kullendorff, Anders
    Biobränsletorkning - en lägesrapport projektet Fluidtork1996Rapport (Övrigt vetenskapligt)
  • 233.
    Bergkvist, Magnus
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för ytbioteknik med Centrum för ytbioteknik.
    Orientation and Conformation of Single Macromolecules on Unmodified and Functionalized Surfaces2002Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    In this thesis methods for investigation of orientation and conformation of individual macromolecules on surfaces are presented as well as novel methods for functionalization of silicon chips with the possibility to get an ordered immobilization of antibodies.

    Two novel methods are presented which makes it possible to investigate the orientation of individual macromolecules on different kinds of surfaces with AFM. One is based on threshold patterning where, depending on substrate, side- and end-on adsorbed immunoglobulin molecules could be detected. The other method is using the principle of site-specific ligands where the orientation of proteins adsorbed to various surfaces was evaluated. By measuring the increase in protein volume of the formed protein-ligand complexes with AFM, the amount of protein having an orientation that allows binding can be estimated.

    The influence of surface chemistry on protein structure was examined using human serum fibronectin adsorbed to hydrophilic and hydrophobic surfaces, where a major difference in structure were seen depending on surface properties.

    In addition, methods for surface functionalization have been developed which are suitable for immobilization of macromolecules and for basic studies of macromolecule/surface interactions at the nanometer scale. In an effort to immobilize protein in a specific orientation that could be studied with AFM, a new method for preparing reactive disulfides based upon a mixed reaction with 2,2’-dipyridyldisulfide and 2-thiopyridone to a mercapto-silanized silica surface was presented. The possibility to covalently bind proteins to this surface was examined, using beta-galactosidase and Fab’-fragments of IgG.

  • 234.
    Berglund, Joel
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    THE PROSPECT OF LIVING FILTERS: Reducing building sector energy demands by improving indoor air quality2018Självständigt arbete på avancerad nivå (yrkesexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [en]

    Today people spend all the more time indoors. Asthma, allergies and Sick Building Syndrome (SBS) are affecting an increasing number of people. The remedy for all these affections has long been to increase the volume flow of outdoor air in the ventilation but at the same time cities all over the world are struggling with air pollution and smog rising above endangering levels. Living filters present a new solution where part of the indoor air can be purified and recirculated in a building. This project has compiled research on the area to describe the how and why concerning air purification by plants. Independent research conclude that plants can reduce most hazardous chemical agents in the air.

    Climate change, global warming and increasing demands on energy performance induces a race for countries and companies to improve energy efficiency in all sectors. To the building engineering sector living filters presents a unique solution to cut ventilation energy loses. A powerful simulation tool IDA ICE was used to estimate the energy saving capacity when a living filter is applied in the lunch room of an office floor. Another simulation software; Comsol Multiphysics was used to illustrate the aspects of ventilation flow when a living filter cabinet is deployed in a room. The simulation results show that for three living filter cabinets each measuring 0,7x0,8x1,73 cm the buildings energy usage is reduced with more than the living filters use to operate. The single room simulations then show how a living filter can be accommodated with both mixing and displacing ventilation. However, these simulations also illustrate the importance of the living filters placement to achieve maximum ventilation efficiency. 

    The conclusions from this work are that living filters can reduce building sector energy demands and provide significant indoor environmental benefits. The main issue for using living filters is identified to be building regulations putting strict demands on outdoor air flow and that the hygienic function of each living filter must be verified before it may replace outdoor air.

  • 235.
    Berglund, Kris
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriell miljö- och processteknik.
    Succinic acid from xylan: fermentations using mixed sugar feedstocks2008Ingår i: NWBC 2008: 2008 Nordic Wood Biorefinery conference : 11-14 March, 2008 : City Conference Centre, Stockholm, Sweden : proceedings, Stockholm: STFI-Packforsk , 2008, s. 121-124Konferensbidrag (Refereegranskat)
    Abstract [en]

    The next generation of cost effective, economically viable biorefinery scenarios requires the development and deployment of higher valued added products whose production can be integrated into a forest biorefinery. We present preliminary results for the production of one such product, succinic acid, from mixed sugars streams including glucose and xylose, as would be present from the hydrolysis of xylan. Examples are presented for the base laboratory case, softwood hydrolysis streams, and hardwood extracts

  • 236.
    Berglund, Kris
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Andersson, Christian
    Luleå tekniska universitet.
    Rova, Ulrika
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Process for the production of succinic acidPatent (Övrig (populärvetenskap, debatt, mm))
    Abstract [en]

    A process for the production of succinic acid can comprise supplying a media with E. coli AFP 184 and a high sugar concentration under aerobic conditions, then converting the media to aerobic conditions. Such a process can be useful when performed in conjunction with the production of ethanol in a biorefmery .

  • 237.
    Berglund, Kris
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriell miljö- och processteknik.
    Falcon, Javier A
    Departments of Chemistry, Chemical Engineering & Materials Science and Agricultural Engineering, Michigan State University, East Lansing, Michigan.
    In situ monitoring of antisolvent addition crystallization with principal components analysis of Raman spectra2004Ingår i: Crystal Growth & Design, ISSN 1528-7483, E-ISSN 1528-7505, Vol. 4, nr 3, s. 457-463Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Fiber optic Raman spectroscopy was used for in situ monitoring of antisolvent addition crystallization of progesterone. Raman spectral features of the solute and the antisolvent were subjected to principal components analysis (PCA) to attempt to obtain information that is not readily apparent from the raw spectral data. For the system utilized, PCA was able to distinguish spectral features from the solute in solution, the solute crystals, and the antisolvent. Furthermore, PCA was capable of detecting subtle changes in the spectral data (as the addition of antisolvent progressed) that could be used as a warning for the onset of crystallization. The current study demonstrates the advantages that can be gained by combining PCA with Raman spectroscopy for monitoring crystallizations in situ.

  • 238. Berglund, Kris
    et al.
    Larson, M.A.
    Iowa State University.
    Modeling of growth rate dispersion of citric acid monohydrate in continuous crystallizers1984Ingår i: AIChE Journal, ISSN 0001-1541, E-ISSN 1547-5905, Vol. 30, nr 2, s. 280-287Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A mathematical model for prediction of the crystal size distribution from a continuous crystallizer is presented. The kinetic data used for the model were obtained from batch contact nucleation experiments with citric acid monohydrate. In these experiments, the distribution of growth rates as well as the initial size distribution were estimated. Results from the model indicate that the excess number of crystals usually present at small sizes in continuous crystallizers is due to growth rate dispersion (where crystals of the same size may have different growth rates) and not size dependent growth.

  • 239. Berglund, Kris
    et al.
    Larson, Maurice A.
    Growth of contact nuclei of citric acid monohydrate1982Ingår i: Nucleation, growth, and impurity effects in crystallization process engineering / [ed] Mary Anne Farrell Epstein, American Institute of Chemical Engineers, 1982, s. 9-13Konferensbidrag (Refereegranskat)
  • 240.
    Berglund, Kris
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Rova, Ulrika
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriell miljö- och processteknik.
    Fermentative Upgrading of Xylose2009Ingår i: NWBC-2009: The 2nd Nordic wood biorefinery conference : Finlandia Hall, Helsinki, Finland, September 2-4, 2009 : Proceedings-Posters / [ed] Annemari Kuokka-Ihalainen., Helsinki: KCL Re-inventing paper , 2009Konferensbidrag (Övrigt vetenskapligt)
    Abstract [en]

    Chemical pulp mills such as Kraft, soda, or sulfite mills are current examples of biorefineries that can convert lignocellulosic biomass into energy, pulp or cellulose derivatives, and tall oil.  While existing viscose pulps use a hemicellulose extraction to generate soluble sugars for ethanol production, in general there still exists a large potential for other more profitable applications of the biomass (Fig. 1), i.e. the mill needs to present a widespread product portfolio.  The biofuels under development from fermentation that will be discussed are the diesel fuel oxygenates dibutyl succinate and diethyl succinate to be used for reduced particulate emissions and fossil fuel replacement for diesel engines and butanol for Otto engines.  It's important to stress that succinic acid, butanol and ethanol, needed for the production of the diesel additives and gasoline replacement will be produced from renewable resources and hence replacing products currently produced from non-renewable fossil sources.  Since wood will be used, there will be no issue of competing with raw material used for food production.  Besides biofuel production, succinic acid and butanol, can be used directly or further refined into numerous different products classified as green chemicals.

  • 241.
    Berglund, Kris
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriell miljö- och processteknik.
    Rova, Ulrika
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriell miljö- och processteknik.
    Hodge, David
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriell miljö- och processteknik.
    Fermentation-Based Building Blocks for Renewable Resource-Based Surfactants2010Ingår i: Surfactants from renewable resources, Chichester: John Wiley & Sons Ltd , 2010, s. 127-141Kapitel i bok, del av antologi (Refereegranskat)
    Abstract [en]

    'new' top-ranked building blocks; Citric acid recovery from fermentation broths and CaCO3 precipitation; Citric, acetic and lactic acid - top three industrial carboxylic acids; Fermentation-based building blocks for renewable resource-based surfactants; Fermentation-based building blocks for surfactants; Filamentous fungi, Aspergillus niger and Candida yeast strains; New fermentation-based building blocks; Organic acid metabolites - as hydrophilic moiety; Sulfonates - largest market share of anionic surfactants; Sulfosuccinate class of surfactants

  • 242.
    Berglund, Linn
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Materialvetenskap.
    From bio-based residues to nanofibers using mechanical fibrillation for functional biomaterials2019Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    Bio-based resource utilization in different forms has been driven by societal, industrial and academic research interests towards the development of “green”, sustainable materials from renewable sources. Within this context, exploiting biomass from different industrial residues is further advantageous from an environmental and economic point of view, leading to minimization of residues by means of waste treatment and to the development of high-addedvalue- products. Breaking down the cell wall structure to its smallest structural components is one means of turning bio-based residues into high-value products, leaving us with nanofibers. The aim of this work has been to understand how these nanofibers can be liberated from various cellulosic sources using mechanical fibrillation and how they can be assembled into functional hydrogels.

    The production of bio-based nanofibers as a sustainable bio-based material is in the early stages of commercialization and considerable research has been devoted to explore different methods of reaching nanoscale. However, the extraction process by chemical and/or mechanical means is still associated with a relatively high energy demand and/or cost. These are key obstacles for use of the material in a wide range of applications. Another challenge is that methods to characterize nanofiber dimensions are still being developed, with few options available as online measurements for assessing the degree of fibrillation. Allowing for assessment during the fibrillation process would enable not only optimization towards a more energy efficient fibrillation, but also matching of the nanofiber quality to its intended function, since different applications will require widely different nanofiber qualities. Energy-efficient fibrillation and scalability from industrial residues were explored using upscalable ultrafine grinding processes.

    Nanofibers from various industrial bio-residues and wood were prepared and characterized, including the development of a method for evaluation of the fibrillation process online via viscosity measurements as an indication of the degree of fibrillation down to nanoscale. Furthermore, the correlation of viscosity to that of the strength of the nanopapers (dried fiber networks) was evaluated for the different raw materials.

    Switchable ionic liquids (SIL) were tested as a green pretreatment for delignification, without bleaching of wood prior to fibrillation, with the aim to preserve the low environmental impact that the raw material source offers.

    In order to employ the hydrophilic nature and strong network formation ability of the fibrillated nanofibers, they were utilized in the preparation of functional biomaterials in the form of hydrogels. Firstly, brewer’s spent grain nanofibers were used to promote and reinforce hydrogel formation of lignin-containing arabinoxylan, resulting in a hydrogel completely derived from barley residues. In addition, alginate-rich seaweed nanofibers from the stipe (stem-like part of the seaweed) were used directly after fibrillation as an ink and hydrogels were formed via 3D printing.

    Publikationen är tillgänglig i fulltext från 2019-10-25 14:00
  • 243.
    Berglund, Linn
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Materialvetenskap.
    Anugwom, Ikenna
    Technical Chemistry, Department of Chemistry, Chemical-Biological Centre, Umeå University .
    Hedenström, Mattias
    Technical Chemistry, Department of Chemistry, Chemical-Biological Centre, Umeå University .
    Aitomäki, Yvonne
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Materialvetenskap.
    Mikkola, Jyri-Pekka
    Technical Chemistry, Department of Chemistry, Chemical-Biological Centre, Umeå University.
    Oksman, Kristiina
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Materialvetenskap. Fibre and Particle Engineering, University of Oulu.
    Switchable ionic liquids enable efficient nanofibrillation of wood pulp2017Ingår i: Cellulose (London), ISSN 0969-0239, E-ISSN 1572-882X, Vol. 24, nr 8, s. 3265-3279Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Use of switchable ionic liquid (SIL) pulp offers an efficient and greener technology to produce nanofibers via ultrafine grinding. In this study, we demonstrate that SIL pulp opens up a mechanically efficient route to the nanofibrillation of wood pulp, thus providing both a low cost and chemically benign route to the production of cellulose nanofibers. The degree of fibrillation during the process was evaluated by viscosity and optical microscopy of SIL treated, bleached SIL treated and a reference pulp. Furthermore, films were prepared from the fibrillated material for characterization and tensile testing. It was observed that substantially improved mechanical properties were attained as a result of the grinding process, thus signifying nanofibrillation. Both SIL treated and bleached SIL treated pulps were fibrillated into nanofibers with fiber diameters below 15 nm thus forming networks of hydrophilic nature with an intact crystalline structure. Notably, it was found that the SIL pulp could be fibrillated more efficiently than traditional pulp since nanofibers could be produced with more than 30% less energy when compared to the reference pulp. Additionally, bleaching reduced the energy demand by further 16%. The study demonstrated that this switchable ionic liquid treatment has considerable potential in the commercial production of nanofibers due to the increased efficiency in fibrillation.

  • 244.
    Berglund, Linn
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Materialvetenskap.
    Forsberg, Fredrik
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Strömningslära och experimentell mekanik.
    Jonoobi, Mehdi
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Materialvetenskap. Department of Wood and Paper Science and Technology, Faculty of Natural Resources, University of Tehran, Karaj, Iran.
    Oksman, Kristiina
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Materialvetenskap. Fibre and Particle Engineering, University of Oulu, Oulu, Finland.
    Promoted hydrogel formation of lignin-containing arabinoxylan aerogel using cellulose nanofibers as a functional biomaterial2018Ingår i: RSC Advances, ISSN 2046-2069, E-ISSN 2046-2069, Vol. 8, nr 67, s. 38219-38228Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In this work, three-dimensional (3D) aerogels and hydrogels based on lignin-containing arabinoxylan (AX) and cellulose nanofibers (CNF) were prepared. The effects of the CNF and the crosslinking with citric acid (CA) of various contents (1, 3, 5 wt%) were evaluated. All the aerogels possessed highly porous (above 98%) and lightweight structures. The AX-CNF hydrogel with a CA content of 1 wt% revealed a favorable network structure with respect to the swelling ratio; nanofiber addition resulted in a five-fold increase in the degree of swelling (68 g of water per g). The compressive properties were improved when the higher CA content (5 wt%) was used; when combined with CNF, there was a seven-fold enhancement in the compressive strength. The AX-CNF hydrogels were prepared using a green and straightforward method that utilizes sustainable resources efficiently. Therefore, such natural hydrogels could find application potential, for example in the field of soft tissue engineering.

  • 245.
    Berglund, Linn
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Materialvetenskap.
    Noël, Maxime
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Materialvetenskap.
    Aitomäki, Yvonne
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Materialvetenskap.
    Öman, Tommy
    Oksman, Kristiina
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Materialvetenskap.
    Production potential of cellulose nanofibers from industrial residues: Efficiency and nanofiber characteristics2016Ingår i: Industrial crops and products (Print), ISSN 0926-6690, E-ISSN 1872-633X, Vol. 92, s. 84-92Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The aim of this study was to evaluate the production potential of cellulose nanofibers from two different industrial bio-residues: wastes from the juice industry (carrot) and the beer brewing process (BSG). The mechanical separation of the cellulose nanofibers was by ultrafine grinding. X-ray diffraction (XRD) and Raman spectroscopy revealed that the materials were mechanically isolated without significantly affecting their crystallinity. The carrot residue was more easily bleached and consumed less energy during grinding, using only 0.9 kWh/kg compared to 21 kWh/kg for the BSG. The carrot residue also had a 10% higher yield than the BSG. Moreover, the dried nanofiber networks showed high mechanical properties, with an average modulus and strength of 12.9 GPa and 210 MPa, respectively, thus indicating a homogeneous nanosize distribution. The study showed that carrot residue has great potential for the industrial production of cellulose nanofibers due to its high quality, processing efficiency, and low raw material cost

  • 246.
    Berglund, Lisa
    KTH, Skolan för bioteknologi (BIO), Proteomik.
    Selection of antigens for antibody-based proteomics2008Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    The human genome is predicted to contain ~20,500 protein-coding genes. The encoded proteins are the key players in the body, but the functions and localizations of most proteins are still unknown. Antibody-based proteomics has great potential for exploration of the protein complement of the human genome, but there are antibodies only to a very limited set of proteins. The Human Proteome Resource (HPR) project was launched in August 2003, with the aim to generate high-quality specific antibodies towards the human proteome, and to use these antibodies for large-scale protein profiling in human tissues and cells.

    The goal of the work presented in this thesis was to evaluate if antigens can be selected, in a high-throughput manner, to enable generation of specific antibodies towards one protein from every human gene. A computationally intensive analysis of potential epitopes in the human proteome was performed and showed that it should be possible to find unique epitopes for most human proteins. The result from this analysis was implemented in a new web-based visualization tool for antigen selection. Predicted protein features important for antigen selection, such as transmembrane regions and signal peptides, are also displayed in the tool. The antigens used in HPR are named protein epitope signature tags (PrESTs). A genome-wide analysis combining different protein features revealed that it should be possible to select unique, 50 amino acids long PrESTs for ~80% of the human protein-coding genes.

    The PrESTs are transferred from the computer to the laboratory by design of PrEST-specific PCR primers. A study of the success rate in PCR cloning of the selected fragments demonstrated the importance of controlled GC-content in the primers for specific amplification. The PrEST protein is produced in bacteria and used for immunization and subsequent affinity purification of the resulting sera to generate mono-specific antibodies. The antibodies are tested for specificity and approved antibodies are used for tissue profiling in normal and cancer tissues. A large-scale analysis of the success rates for different PrESTs in the experimental pipeline of the HPR project showed that the total success rate from PrEST selection to an approved antibody is 31%, and that this rate is dependent on PrEST length. A second PrEST on a target protein is somewhat less likely to succeed in the HPR pipeline if the first PrEST is unsuccessful, but the analysis shows that it is valuable to select several PrESTs for each protein, to enable generation of at least two antibodies, which can be used to validate each other.

  • 247.
    Berglund, Lisa
    et al.
    KTH, Skolan för bioteknologi (BIO).
    Andrade, Jorge
    KTH, Skolan för bioteknologi (BIO).
    Odeberg, Jacob
    KTH, Skolan för bioteknologi (BIO).
    Uhlén, Mathias
    KTH, Skolan för bioteknologi (BIO).
    The epitope space of the human proteome2008Ingår i: Protein Science, ISSN 0961-8368, E-ISSN 1469-896X, Vol. 17, nr 4, s. 606-613Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In the post-genome era, there is a great need for protein-specific affinity reagents to explore the human proteome. Antibodies are suitable as reagents, but generation of antibodies with low cross-reactivity to other human proteins requires careful selection of antigens. Here we show the results from a proteomewide effort to map linear epitopes based on uniqueness relative to the entire human proteome. The analysis was based on a sliding window sequence similarity search using short windows (8, 10, and 12 amino acid residues). A comparison of exact string matching (Hamming distance) and a heuristic method (BLAST) was performed, showing that the heuristic method combined with a grid strategy allows for whole proteome analysis with high accuracy and feasible run times. The analysis shows that it is possible to find unique antigens for a majority of the human proteins, with relatively strict rules involving low sequence identity of the possible linear epitopes. The implications for human antibody-based proteomics efforts are discussed.

  • 248.
    Berglund, Lisa
    et al.
    KTH, Skolan för bioteknologi (BIO).
    Björling, Erik
    KTH, Skolan för bioteknologi (BIO).
    Gry, Marcus
    KTH, Skolan för bioteknologi (BIO).
    Asplund, Anna
    Uppsala Univ, Rudbeck laboratory.
    Al-Khalili Szigyarto, Cristina
    KTH, Skolan för bioteknologi (BIO).
    Persson, Anja
    KTH, Skolan för bioteknologi (BIO).
    Ottoson, Jenny
    KTH, Skolan för bioteknologi (BIO).
    Wernérus, Henrik
    KTH, Skolan för bioteknologi (BIO).
    Nilsson, Peter
    KTH, Skolan för bioteknologi (BIO).
    Sivertsson, Åsa
    KTH, Skolan för bioteknologi (BIO).
    Wester, Kenneth
    Uppsala Univ, Rudbeck laboratory.
    Kampf, Caroline
    Uppsala Univ, Rudbeck laboratory.
    Hober, Sophia
    KTH, Skolan för bioteknologi (BIO).
    Pontén, Fredrik
    Uppsala Univ, Rudbeck laboratory.
    Uhlén, Mathias
    KTH, Skolan för bioteknologi (BIO).
    Generation of validated antibodies towards the human proteomeArtikel i tidskrift (Övrigt vetenskapligt)
    Abstract [en]

    Here we show the results from a large effort to generate antibodies towards the human proteome. A high-throughput strategy was developed based on cloning and expression of antigens as recombitant protein epitope signature tags (PrESTs) Affinity purified polyclonal antibodies were generated, followed by validation by protein microarrays, Western blotting and microarray-based immunohistochemistry. PrESTs were selected based on sequence uniqueness relative the proteome and a bioinformatics analysis showed that unique antigens can be found for at least 85% of the proteome using this general strategy. The success rate from antigen selection to validated antibodies was 31%, and from protein to antibody 55%. Interestingly, membrane-bound and soluble proteins performed equally and PrEST lengths between 75 and 125 amino acids were found to give the highest yield of validated antibodies. Multiple antigens were selected for many genes and the results suggest that specific antibodies can be systematically generated to most human proteibs.

  • 249.
    Berglund, Lisa
    et al.
    KTH, Skolan för bioteknologi (BIO).
    Björling, Erik
    KTH, Skolan för bioteknologi (BIO).
    Jonasson, Kalle
    KTH, Skolan för bioteknologi (BIO).
    Rockberg, Johan
    KTH, Skolan för bioteknologi (BIO).
    Fagerberg, Linn
    KTH, Skolan för bioteknologi (BIO).
    Al-Khalili Szigyarto, Cristina
    KTH, Skolan för bioteknologi (BIO).
    Sivertsson, Åsa
    KTH, Skolan för bioteknologi (BIO).
    Uhlén, Mathias
    KTH, Skolan för bioteknologi (BIO).
    A whole-genome bioinformatics approach to selection of antigens for systematic antibody generation2008Ingår i: Proteomics, ISSN 1615-9853, E-ISSN 1615-9861, Vol. 8, nr 14, s. 2832-2839Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Here, we present an antigen selection strategy based on a whole-genome bioinformatics approach, which is facilitated by an interactive visualization tool displaying protein features from both public resources and in-house generated data. The web-based bioinformatics platform has been designed for selection of multiple, non-overlapping recombinant protein epitope signature tags by display of predicted information relevant for antigens, including domain- and epitope sized sequence similarities to other proteins, transmembrane regions and signal peptides. The visualization tool also displays shared and exclusive protein regions for genes with multiple splice variants. A genome-wide analysis demonstrates that antigens for approximately 80% of the human protein-coding genes can be selected with this strategy.

  • 250.
    Berglund, Lisa
    et al.
    KTH, Skolan för bioteknologi (BIO), Proteomik.
    Björling, Erik
    KTH, Skolan för bioteknologi (BIO), Proteomik.
    Oksvold, Per
    KTH, Skolan för bioteknologi (BIO), Proteomik.
    Fagerberg, Linn
    KTH, Skolan för bioteknologi (BIO), Proteomik.
    Al-Khalili Szigyarto, Cristina
    KTH, Skolan för bioteknologi (BIO), Proteomik.
    Persson, Anja
    KTH, Skolan för bioteknologi (BIO), Proteomik.
    Ottosson, Jenny
    KTH, Skolan för bioteknologi (BIO), Proteomik.
    Wernérus, Henrik
    KTH, Skolan för bioteknologi (BIO), Proteomik.
    Nilsson, Peter
    KTH, Skolan för bioteknologi (BIO), Proteomik.
    Lundberg, Emma
    KTH, Skolan för bioteknologi (BIO), Proteomik.
    Sivertsson, Åsa
    KTH, Skolan för bioteknologi (BIO), Proteomik.
    Hober, Sophia
    KTH, Skolan för bioteknologi (BIO), Proteomik.
    Uhlén, Mathias
    KTH, Skolan för bioteknologi (BIO), Proteomik.
    et al.,
    A genecentric human protein atlas for expression profiles based on antibodies2008Ingår i: Molecular & Cellular Proteomics, ISSN 1535-9476, Vol. 7, nr 10, s. 2019-2027Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    An attractive path forward in proteomics is to experimentally annotate the human protein complement of the genome in a genecentric manner. Using antibodies, it might be possible to design protein-specific probes for a representative protein from every protein-coding gene and to subsequently use the antibodies for systematical analysis of cellular distribution and subcellular localization of proteins in normal and disease tissues. A new version (4.0) of the Human Protein Atlas has been developed in a genecentric manner with the inclusion of all human genes and splice variants predicted from genome efforts together with a visualization of each protein with characteristics such as predicted membrane regions, signal peptide, and protein domains and new plots showing the uniqueness (sequence similarity) of every fraction of each protein toward all other human proteins. The new version is based on tissue profiles generated from 6120 antibodies with more than five million immunohistochemistry-based images covering 5067 human genes, corresponding to similar to 25% of the human genome. Version 4.0 includes a putative list of members in various protein classes, both functional classes, such as kinases, transcription factors, G-protein-coupled receptors, etc., and project-related classes, such as candidate genes for cancer or cardiovascular diseases. The exact antigen sequence for the internally generated antibodies has also been released together with a visualization of the application-specific validation performed for each antibody, including a protein array assay, Western blot analysis, immunohistochemistry, and, for a large fraction, immunofluorescence-based confocal microscopy. New search functionalities have been added to allow complex queries regarding protein expression profiles, protein classes, and chromosome location. The new version of the protein atlas thus is a resource for many areas of biomedical research, including protein science and biomarker discovery.

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