| 1. |
|
|
| 2. |
- Osong, Sinke Henshaw, et al.
(författare)
-
Nanofibrillated cellulose/nanographite composite films
- 2016
-
Ingår i: Cellulose. - : Springer Science and Business Media LLC. - 0969-0239 .- 1572-882X. ; 23:4, s. 2487-2500
-
Tidskriftsartikel (refereegranskat)abstract
- Though research into nanofibrillated cellulose (NFC) has recently increased, few studies have considered co-utilising NFC and nanographite(NG) in composite films, and, it has, however been a challenge to use high-yield pulp fibres (mechanical pulps) to produce this nanofibrillar material. It is worth noting that there is a significant difference between chemical pulp fibres and high-yield pulp fibres, as the former is composed mainly of cellulose and has a yield of approximately 50 % while the latter is consist of cellulose, hemicellulose and lignin, and has a yield of approximately 90 %. NFC was produced by combining TEMPO (2,2,6,6-tetramethypiperidine-1-oxyl)-mediated oxidation with the mechanical shearing of chemi-thermomechanical pulp (CTMP) and sulphite pulp (SP); the NG was produced by mechanically exfoliating graphite. The different NaClO dosages in the TEMPO system differently oxidised the fibres, altering their fibrillation efficiency. NFC-NG films were produced by casting in a Petri dish. We examine the effect of NG on the sheet-resistance and mechanical properties of NFC films. Addition of 10 wt% NG to 90 wt% NFC of sample CC2 (5 mmol NaClO CTMP-NFC homogenised for 60 min) improved the sheet resistance, i.e. from that of an insulating pure NFC film to 180 Omega/sq. Further addition of 20 (CC3) and 25 wt% (CC4) of NG to 80 and 75 wt% respectively, lowered the sheet resistance to 17 and 9 Omega/sq, respectively. For the mechanical properties, we found that adding 10 wt% NG to 90 wt% NFC of sample HH2(5 mmol NaClO SP-NFC homogenised for 60 min) improved the tensile index by 28 %, tensile stiffness index by 20 %, and peak load by 28 %. The film's surface morphology was visualised using scanning electron microscopy, revealing the fibrillated structure of NFC and NG. This methodology yields NFC-NG films that are mechanically stable, bendable, and flexible.
|
|
| 3. |
|
|
| 4. |
|
|
| 5. |
- Andersson, Henrik, et al.
(författare)
-
Contacting paper-based supercapacitors to printed electronics on paper substrates
- 2012
-
Ingår i: Nordic Pulp & Paper Research Journal. - 0283-2631 .- 2000-0669. ; 27:2, s. 476-480
-
Tidskriftsartikel (refereegranskat)abstract
- Hybrid printed electronics, in which printed structures and silicon-based components co-exist will likely be among the first commercial solutions. In this case the paper substrate acts much in the same way as circuit boards, containing conductive tracks and acting as a carrier for the electrical components. It is important to consider the contacting of the components to be able to produce low resistance electrical contacts to the conductive tracks. Supercapacitors are able to deliver a large amount of current in a short time and are a good option for short term energy storage and if the printed product is to be used only one, or a few times, it can be the only power source needed. When manufacturing printed electronics, the overall resistance of the printed tracks as well as the contact resistance of the mounted components will add up to the total resistance of the system. A high resistance will cause a voltage drop from the power source to the component. This will waste power that goes to Joule heating and also the voltage and current available to components may be too low to drive them. If the intention is to use a power supply such as batteries or solar cells this becomes a limitation. In this article have been tested several conductive adhesives used to contact paper based supercapacitors to ink jet printed silver tracks on paper. The best adhesive gives about 0.3 Ω per contact, a factor 17 better compared to the worst which gave 5 Ω. The peak power that is possible to take out from a printed system with a flexible battery and super capacitors is about 10 times higher than compared with the same system with only the battery.
|
|
| 6. |
- Andersson, Henrik, et al.
(författare)
-
Evaluation of coatings applied to flexible substrates to enhance quality of ink jet printed silver nano-particle structures
- 2012
-
Ingår i: IEEE Transactions on Components, Packaging, and Manufacturing Technology, Part C. - 1083-4400 .- 1558-1241. ; 2:2, s. 342-348
-
Tidskriftsartikel (refereegranskat)abstract
- Different types of the commercial surface treatment InkAid have been evaluated as a surface treatment to enhance print quality of silver nano-particle ink structures printed on polyimide and polyethene substrate. Originally these coatings have been specified to be applied on substrates for graphical ink jet printing. On the coated polyimide and polyethene substrates lines of different widths have been printed using a Dimatix materials printer together with silver nano-particle ink manufactured by Advanced Nano Products. The prints have then been evaluated in terms of print quality and resistivity before and after sintering. The results show that the application of these coatings can improve the print quality considerably, making it possible to print lines with a good definition, which is not otherwise possible with this type of ink on this substrate types. It has been found that the coating Semi Gloss provides the best results, both in terms of print quality as well as the lowest resistivity. The resistivity on polyethene is 3.5*10-7Ωm at best when sintered at 150°C and for polyimide 8.9*10-8Ωm sintered at 200°C. This corresponds to a conductivity of about 4.5% and 18%of bulk silver, respectively. It can be concluded that applying such PVP based coatings to polyethene and polyimide will increase the print quality quite substantially, making it possible to print patterns with requirements of smaller line widths and more details than what is possible without coating.
|
|
| 7. |
|
|
| 8. |
- Andersson, Henrik, et al.
(författare)
-
Inkjet printed silver nanoparticle humidity sensor with memory effect on paper
- 2012
-
Ingår i: IEEE Sensors Journal. - 1530-437X .- 1558-1748. ; 12:6, s. 1901-1905
-
Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- In this paper, the design and the manufacture of an inkjet printed resistive type humidity sensor on paper are reported. After having been exposed to humidity above a given threshold level, the resistance of the sensor decreases substantially and remains at that level even when thehumidity is reduced. It is possible to deduce the humidity level by monitoring the resistance. The main benefit of the printed sensor presented in this case is in relation to its very low production costs. It has also been shown that both the ink type and this paper combination used prove to be crucial in order to obtain the desired sensor effect. More research is required in order to fully understand the humidity sintering effect on the nano particle ink and the role of the substrate. However, the observed effect can be put to use in printed humidity sensors which possess a memoryfunction. The sensor can be used in various applications for environmental monitoring, for example, in situations where a large number of inexpensive and disposable humidity sensors are required which are able to detect whether they have been subjected to high humidity. This could be the checking of transportation conditions of goods or monitoring humidity within buildings. © 2001-2012 IEEE.
|
|
| 9. |
- Andersson, Henrik, et al.
(författare)
-
Investigation of Humidity Sensor Effect in Silver Nanoparticle Ink Sensors Printed on Paper
- 2014
-
Ingår i: IEEE Sensors Journal. - 1530-437X .- 1558-1748. ; 14:3, s. Art. no. 6615915-
-
Tidskriftsartikel (refereegranskat)abstract
- Thin inkjet-printed tracks of silver nanoparticles have previously been observed to show a non-reversible decrease in resistance when exposed to a high degree of relative humidity and thus providing sensor functionality with a memory effect. This paper provides a more in-depth explanation of the observed humidity sensor effect that originates from inkjet-printed silver nanoparticle sensors on a paper substrate. It is shown that the geometry of the sensor has a large effect on the sensor's initial resistance, and therefore also on the sensor's resistive dynamic range. The importance of the sensor geometry is believed to be due to the amount of solvent from the ink interacting with the coating of the paper substrate, which in turn enables the diffusion of salts from the paper coating into the ink and thus affecting the silver ink.
|
|
| 10. |
- Andersson, Henrik, et al.
(författare)
-
The influence of paper coating content on room temperature sintering of silver nanoparticle ink
- 2013
-
Ingår i: Nanotechnology. - : IOP Publishing. - 0957-4484 .- 1361-6528. ; 24:45, s. Art. no. 455203-
-
Tidskriftsartikel (refereegranskat)abstract
- The resistance of inkjet printed lines using a silver nanoparticle based ink can be very dependent on the substrate. A very large difference in resistivity was observed for tracks printed on paper substrates with aluminum oxide based coatings compared to silica based coatings. Silica based coatings are often cationized with polymers using chloride as a counter ion. It is suggested that the precipitation of silver salts is the cause of the high resistivity, since papers pretreated with salt solutions containing ions that precipitate silver salts gave a high resistance. Silver nitrate has a high solubility and paper pretreated with nitrate ions gave a low resistivity without sintering. The results obtained show that, by choosing the correct type of paper substrate, it is possible to manufacture printed structures, such as interconnects on paper, without the need for, or at least to reduce the need for, post-print sintering. This phenomenon is, of course, ink specific. Inks without or with a low silver ion content are not expected to behave in this manner. In some sensor applications, a high resistivity is desired and, by using the correct combination of ink and paper, these types of sensors can be facilitated.
|
|
| 11. |
- Andréasson, Maia, 1960, et al.
(författare)
-
Swedish CLARIN activities
- 2009
-
Ingår i: Proceedings of the Nodalida 2009 workshop on CLARIN activities in the Nordic countries. NEALT Proceedings Series. - 1736-6305. ; 5, s. 1-5
-
Konferensbidrag (refereegranskat)
|
|
| 12. |
- Andréasson, Maia, et al.
(författare)
-
Swedish CLARIN Activities
- 2009
-
Ingår i: Proceedings of the NODALIDA 2009 workshop Nordic Perspectives on the CLARIN Infrastructure of Language Resources. - : Northern European Association for Language Technology (NEALT). ; , s. 1-5
-
Konferensbidrag (refereegranskat)abstract
- Although Sweden has yet to allocate funds specifically intended for CLARIN activities, there are some ongoing activities which are directly relevant to CLARIN, and which are explicitly linked to CLARIN. These activities have been funded by the Committee for Research Infrastructures and its subcommittee DISC (Database Infrastructure Committee) of the Swedish Research Council.
|
|
| 13. |
|
|
| 14. |
- Andres, Britta, et al.
(författare)
-
Characterization of nanographite and graphene produced in a high-pressure homogenizer
- 2014
-
Ingår i: Graphene Week 2014.
-
Konferensbidrag (refereegranskat)abstract
- Supercapacitor electrodes are often made of porous carbon materials such as activated carbon, but also graphene was frequently used as active electrode material. Graphene can be produced by mechanical exfoliation, chemical exfoliation, chemical vapor deposition or other elaborate methods. These techniques are relatively expensive and produce small quantities only. Recently we presented a method to produce nanographite and graphene by mechanical exfoliation of graphite in a high-pressure homogenizer. In our contribution “Large-scale production of graphene” by Nicklas Blomquist we suggest to optimize the geometry of the shear zone and increase the feeding pressure to obtain a higher yield.In this study we evaluated the influence of these process optimizations on the structural and electrical properties of the nanographite-graphene mixture. The produced dispersions were characterized in terms of particle size and shape by using a particle size analyzer, a transmission electron microscope (TEM) and an atomic force microscope (AFM). In order to analyze the performance of the produced material as electrodes for supercapacitors, electrodes were produced by vacuum filtration. The electrodes were studied by sheet-resistance and capacitance measurements. Furthermore, the structure of the electrode surface and the cross section of the electrode were visualized by using a scanning electron microscope (SEM).Comparisons with previously produced nanographite-graphene dispersions showed an increase in yield of the exfoliated nanomaterials. The optimized shear zone increased the production of nanosized particles and flakes and enhanced the material quality.
|
|
| 15. |
- Andres, Britta, 1986-, et al.
(författare)
-
Electrode Mass Balancing as an Inexpensive and Simple Method to Increase the Capacitance of Electric Double-Layer Capacitors
- 2016
-
Ingår i: PLOS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 11:9, s. 1-12
-
Tidskriftsartikel (refereegranskat)abstract
- Symmetric electric double-layer capacitors (EDLCs) have equal masses of the same active material in both electrodes. However, having equal electrode masses may prevent the EDLC to have the largest possible specific capacitance if the sizes of the hydrated anions and cations in the electrolyte differ because the electrodes and the electrolyte may not be completely utilized. Here we demonstrate how this issue can be resolved by mass balancing. If the electrode masses are adjusted according to the size of the ions, one can easily increase an EDLC's specific capacitance. To that end, we performed galvanostatic cycling to measure the capacitances of symmetric EDLCs with different electrode mass ratios using four aqueous electrolytes-Na2SO4, H2SO4, NaOH, and KOH (all with a concentration of 1 M)-and compared these to the theoretical optimal electrode mass ratio that we calculated using the sizes of the hydrated ions. Both the theoretical and experimental values revealed lower-than-1 optimal electrode ratios for all electrolytes except KOH. The largest increase in capacitance was obtained for EDLCs with NaOH as electrolyte. Specifically, we demonstrate an increase of the specific capacitance by 8.6% by adjusting the electrode mass ratio from 1 to 0.86. Our findings demonstrate that electrode mass balancing is a simple and inexpensive method to increase the capacitance of EDLCs. Furthermore, our results imply that one can reduce the amount of unused material in EDLCs and thus decrease their weight, volume and cost.
|
|
| 16. |
- Andres, Britta, 1986-, et al.
(författare)
-
Enhanced electrical and mechanical properties of nanographite electrodes for supercapacitors by addition of nanobrillated cellulose
- 2014
-
Konferensbidrag (refereegranskat)abstract
- Graphene and other porous carbon materials are widely used as electrodes in supercapacitors. In order to form mechanically stable electrodes, binders can be added to the conducting electrode material. However, most binders degrade the electrical performance of the electrodes. Here we show that by using nanobrillated cellulose (NFC) as binder the electrical properties, such as sheet-resistance, were enhanced. NFC is a good ion conductor and improves the access of ions to the electrodes. Thus electrodes made of a mixture of nanographite and NFC achieved larger capacitances in supercapacitors than electrodes with nanographite only. The lowest sheet-resistance and the highest capacitance were measured at NFC contents of 10-15% in ratio to the total amount of active material. Furthermore, NFC formed a network that improved the mechanical stability of the electrodes signicantly. Beside the mechanical stability, NFC stabilized the aqueous nanographite dispersion that was used to prepare the electrodes. NFC avoids the restacking of the delaminated graphene akes by forming a ber network between the graphene layers.
|
|
| 17. |
- Andres, Britta, et al.
(författare)
-
Enhanced electrical and mechanical properties of nanographite electrodes for supercapacitors by addition of nanofibrillated cellulose
- 2014
-
Ingår i: Physica status solidi. B, Basic research. - : Wiley. - 0370-1972 .- 1521-3951. ; 251:12, s. 2581-2586
-
Tidskriftsartikel (refereegranskat)abstract
- Graphene and porous carbon materials are widely used as electrodes in supercapacitors. In order to form mechanically stable electrodes, binders can be added to the conducting electrode material. However, most bindersdegrade the electrical performance of the electrodes. Here we show that by using nanofibrillated cellulose(NFC) as binder the electrical properties, such as capacitance, were enhanced. The highest capacitance was measured at a NFC content of approximately 10% in ratio to the total amount of active material. NFC is a good ionconductor and improves the access of ions in the electrodes. Thus, electrodes made of a mixture of nanographite and NFC achieved larger capacitances in supercapacitors than electrodes with nanographite only. In addition to electrical properties, NFC enhanced the mechanical stability and wet strength of the electrodes significantly. Furthermore, NFC stabilized the aqueous nanographite dispersions, which improved the processability. Galvanostatic cycling was performed and an initial transient behaviour of the supercapacitors during the first cycles was observed. However, stabilized supercapacitors showed efficiencies of 98–100 %.
|
|
| 18. |
|
|
| 19. |
|
|
| 20. |
- Andres, Britta, et al.
(författare)
-
Supercapacitors with graphene coated paper electrodes
- 2012
-
Ingår i: Nordic Pulp & Paper Research Journal. - 0283-2631 .- 2000-0669. ; 27:2, s. 481-485
-
Tidskriftsartikel (refereegranskat)abstract
- Paper based supercapacitors are prepared by stacking a paper between two graphene electrodes and soaking these in an aqueous electrolyte. We demonstrate that supercapacitors can easily be manufactured by using proven paper technologies. Several different electrode materials were compared and two types of contacting material, silver and graphite foil were tested. The influence of the paper used as separator was also investigated. The supercapacitors with a graphene-gold nanoparticle composite as electrodes showed a specific capacitance of up to 100 F/g and an energy density of 1.27 Wh/kg. The energy density can further be increased by using other electrolytes. The silver contacts showed a pseudo capacitance, which the graphite contacts did not. The papers tested had a minor effect on the capacitance, but they have an influence on the weight and the volume of the supercapacitor.
|
|
| 21. |
|
|
| 22. |
- Axsäter, Sven, et al.
(författare)
-
Approximating general multi-echelon inventory systems by Poisson models
- 1994
-
Ingår i: International Journal of Production Economics. - : Elsevier BV. - 0925-5273 .- 1873-7579. ; 35:1-3, s. 201-206
-
Tidskriftsartikel (refereegranskat)abstract
- We consider a continuous review two-level inventory system with a central warehouse and a number of retailers. The demand processes at the retailers are different compound Poisson processes. We present and evaluate an approximate optimization technique, where the real demand is replaced by "equivalent" Poisson demand such that the ratio between mean and standard deviation is the same as for the real distribution. The solution of the Poisson model is then scaled back to the original problem.
|
|
| 23. |
- Baison, J., et al.
(författare)
-
Genetic control of tracheid properties in Norway spruce wood
- 2020
-
Ingår i: Scientific Reports. - : Nature Research. - 2045-2322. ; 10:1
-
Tidskriftsartikel (refereegranskat)abstract
- Through the use of genome-wide association studies (GWAS) mapping it is possible to establish the genetic basis of phenotypic trait variation. Our GWAS study presents the first such effort in Norway spruce (Picea abies (L). Karst.) for the traits related to wood tracheid characteristics. The study employed an exome capture genotyping approach that generated 178 101 Single Nucleotide Polymorphisms (SNPs) from 40 018 probes within a population of 517 Norway spruce mother trees. We applied a least absolute shrinkage and selection operator (LASSO) based association mapping method using a functional multi-locus mapping approach, with a stability selection probability method as the hypothesis testing approach to determine significant Quantitative Trait Loci (QTLs). The analysis has provided 30 significant associations, the majority of which show specific expression in wood-forming tissues or high ubiquitous expression, potentially controlling tracheids dimensions, their cell wall thickness and microfibril angle. Among the most promising candidates based on our results and prior information for other species are: Picea abies BIG GRAIN 2 (PabBG2) with a predicted function in auxin transport and sensitivity, and MA_373300g0010 encoding a protein similar to wall-associated receptor kinases, which were both associated with cell wall thickness. The results demonstrate feasibility of GWAS to identify novel candidate genes controlling industrially-relevant tracheid traits in Norway spruce. © 2020, The Author(s).
|
|
| 24. |
- Baison, John, et al.
(författare)
-
Genome-Wide Association Study (GWAS) identified novel candidate loci affecting wood formation in Norway spruce
- 2019
-
Ingår i: The Plant Journal. - : Wiley. - 0960-7412 .- 1365-313X. ; 100:1, s. 83-100
-
Tidskriftsartikel (refereegranskat)abstract
- Norway spruce is a boreal forest tree species of significant ecological and economic importance. Hence there is a strong imperative to dissect the genetics underlying important wood quality traits in the species. We performed a functional Genome-Wide Association Study (GWAS) of 17 wood traits in Norway spruce using 178101 single-nucleotide polymorphisms (SNPs) generated from exome genotyping of 517 mother trees. The wood traits were defined using functional modelling of wood properties across annual growth rings.We applied a LASSO based association mapping method using a functional multi-locus mapping approach that utilizes latent traits, with a stability selection probability method as the hypothesis testing approach to determine significant Quantitative Trait Loci (QTLs). The analysis provided 52 significant SNPs from 39 candidate genes, including genes previously implicated in wood formation and tree growth in spruce and other species. Our study represents a multi-locus GWAS for complex wood traits in Norway spruce. The results advance our understanding of the genetics influencing wood traits and identifies candidate genes for future functional studies.
|
|
| 25. |
- Baison, John, et al.
(författare)
-
Genome-wide association study identified novel candidate loci affecting wood formation in Norway spruce
- 2019
-
Ingår i: The Plant Journal. - : John Wiley & Sons. - 0960-7412 .- 1365-313X. ; 100:1, s. 83-100
-
Tidskriftsartikel (refereegranskat)abstract
- Norway spruce is a boreal forest tree species of significant ecological and economic importance. Hence there is a strong imperative to dissect the genetics underlying important wood quality traits in the species. We performed a functional genome-wide association study (GWAS) of 17 wood traits in Norway spruce using 178 101 single nucleotide polymorphisms (SNPs) generated from exome genotyping of 517 mother trees. The wood traits were defined using functional modelling of wood properties across annual growth rings. We applied a Least Absolute Shrinkage and Selection Operator (LASSO-based) association mapping method using a functional multilocus mapping approach that utilizes latent traits, with a stability selection probability method as the hypothesis testing approach to determine a significant quantitative trait locus. The analysis provided 52 significant SNPs from 39 candidate genes, including genes previously implicated in wood formation and tree growth in spruce and other species. Our study represents a multilocus GWAS for complex wood traits in Norway spruce. The results advance our understanding of the genetics influencing wood traits and identifies candidate genes for future functional studies.
|
|
| 26. |
- Balliu, Enkeleda, et al.
(författare)
-
Laser-assisted reduction of graphene oxide for paper based large area flexible electronics
- 2016
-
Ingår i: Proceedings of SPIE - The International Society for Optical Engineering. - : SPIE - International Society for Optical Engineering. - 9781628419719
-
Konferensbidrag (refereegranskat)abstract
- In this work we present a promising method for fabrication of conductive tracks on paper based substrates by laser assisted reduction of Graphene Oxide (GO). Printed electronics on paper based substrates is be coming more popular due to lower cost and recyclability. Fabrication of conductive tracks is of great importance where metal, carbon and polymer inks are commonly used. An emerging option is reduced graphene oxide (r-GO), which can be a good conductor. Here we have evaluated reduction of GO by using a 532 nm laser source, showing promising results with a decrease of sheet resistance from >100 M Ω/Sqr for unreduced GO down to 126 Ω/Sqr. without any observable damage to the paper substrates.
|
|
| 27. |
- Balliu, Enkeleda, PhD student, et al.
(författare)
-
Laser processing of graphene oxide on different coated paper substrates
- 2016
-
Ingår i: 14th TAPPI Advanced Coating Symposium 2016. - : TAPPI Press. - 9781510877658 ; , s. 97-101
-
Konferensbidrag (refereegranskat)abstract
- Development of printed electronics is increasing each year, where many electrical components such as transistors and sensors are now printable. The most commonly used substrate have been plastics, but there is an increasing interest in using paper as substrate. The paper industry is a very large and mature industry with large production capacity and well developed processes. It is therefore of interest to investigate how it would be possible to combine printed electronics and paper based products. This can for example be to print sensors on packages, to use large scale roll-to-roll production for solar cells. To be able to achieve such goals it is of importance to develop methods of applying electrically active materials in the large, high speed roll-to-roll processes used in the paper industry. In this article we discuss coating of graphene oxide (GO) on large areas after which it is selectively reduced into electrically conductive reduced graphene oxide (rGO) by laser processing. Graphene oxide is an inexpensive, carbon based material very suitable to be deposited as a coating, and the selective activation of makes it possible to fabricate conductive patterns at high speeds. We have evaluated several different paper substrates on which GO was coated. The reduction was performed using an 532 nm laser source and the results are promising, showing that it is possible to fabricate selectively conductive patterns on paper substrates by coating and reduction of GO.
|
|
| 28. |
|
|
| 29. |
- Baskaran, Sathishkumar, 1988-
(författare)
-
New Molecular Approaches to Glioblastoma Therapy
- 2017
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Glioblastoma (GBM) is the most common high-grade brain tumor diagnosed in patients who are more than 50 years of age. The standard of care treatment is surgery, followed by radiotherapy and chemotherapy. The median life expectancy of patients is only between 12 to 15 months after receiving current treatment regimes. Hence, identification of new therapeutic compounds and gene targets are highly warranted. This thesis describes four interlinked studies to attain this goal. In study 1, we explored drug combination effects in a material of 41 patient-derived GBM cell (GC) cultures. Synergies between three compounds, pterostilbene, gefitinib, and sertraline, resulted in effective killing of GC and can be predicted by biomarkers. In study 2, we performed a large-scale screening of FDA approved compounds (n=1544) in a larger panel of GCs (n=106). By combining the large-scale drug response data with GCs genomics data, we built a novel computational model to predict the sensitivity of each compound for a given GC. A notable finding was that GCs respond very differently to proteasome inhibitors in both in-vitro and in-vivo. In study 3, we explored new gene targets by RNAi (n=1112) in a panel of GC cells. We found that loss of transcription factor ZBTB16/PLZF inhibits GC cell viability, proliferation, migration, and invasion. These effects were due to downregulation of c-MYC and Cyclin B1 after the treatment. In study 4, we tested the genomic stability of three GCs upon multiple passaging. Using molecular and mathematical analyses, we showed that the GCs undergo both systematic adaptations and sequential clonal takeovers. Such changes tend to affect a broad spectrum of pathways. Therefore, a systematic analysis of cell culture stability will be essential to make use of primary cells for translational oncology.Taken together, these studies deepen our knowledge of the weak points of GBM and provide several targets and biomarkers for further investigation. The work in this thesis can potentially facilitate the development of targeted therapies and result in more accurate tools for patient diagnostics and stratification.
|
|
| 30. |
|
|
| 31. |
- Bergström, Tobias, 1980-
(författare)
-
Modeling Neural Stem Cell and Glioma Biology
- 2013
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This thesis is focused on neural stem cell (NSC) and glioma biology. I discuss how NSCs interact with extracellular matrix (ECM) proteins in the stem cell niche, and investigate the consequences of deregulated Platelet-derived growth factor (PDGF) signaling for embryonic NSCs in transgenic mice. Furthermore I present cell cultures of human glioblastoma multiforme (GBM) that models human disease, taking into account the heterogeneity of GBM. Finally, interactions between brain tumors and mast cells are studied using the glioma cultures.In paper I, the importance of NSC interactions with the ECM in the stem cell niche during development is discussed. Contacts between NSCs and the ECM in the subventricular zone (SVZ) are emerging as important regulatory mechanisms. We show that early postnatal neural stem and progenitor cells (NSPC) attach to collagen I, and that the adhesion is explained by higher expression of collagen receptor integrins compared to adult NSPC. Further, blood vessels in the SVZ express collagen I, indicating a possible functional relationship.Growth factors, e.g. PDGF, regulate NSC proliferation and differentiation. Aberrant activation of growth factor signaling pathways also plays a role in brain tumor formation. Paper II demonstrates that transgenic mice expressing PDGF-B at high levels in embryonic NSCs displayed mild neurological defects but no hyperplasia or brain tumors. This suggests that a high level of PDGF is not sufficient to induce brain tumors from NSCs without further mutations.Paper III presents a novel panel of human glioma stem cell (GSC) lines from GBM that display NSC markers in vitro and form secondary orthotopic tumors in vivo. GBM has recently been categorized in molecular subclasses and we demonstrate, for the first time, that these subclasses can be retained in vitro by stem cell culture conditions. We have thus generated models for research and drug development aiming at a focused treatment depending on GBM subtype.Interactions with the immune system are integral parts of tumorigenesis. Mast cells are found in glioma and in paper IV we demonstrate that the grade-dependent infiltration of mast cells is in part mediated by macrophage migration inhibitory factor and phosphorylation of STAT5.
|
|
| 32. |
- Besharati, Farshid, et al.
(författare)
-
The EVI Distributed Shared Memory System
- 2015
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- With the data handled by companies and research institutes getting larger and larger every day, there is a clear need for faster computing. At the same time, we have reached the limit of power consumption and more power efficient computing is also called for, both in the datacenter and in the supercomputer room. For that, there is a great push, both in industry and academia, towards increasing the amount of computing power per watt consumed. With this shift towards a different computing paradigm, many older ideas are looked upon in a new light. One of these is the distributed shared memory (DSM) systems. It is becoming harder and harder to achieve higher performance and better power efficiency at the same form factor as we have always had. Furthermore, while we have seen a stop in the constant increase of processor speeds, there is a constant increase in network communication speeds. Software implemented DSM is again a viable solution for high performance computing, without the need for sacrificing ease of programming for performance gains. The goal of this course was to develop such a system, and learn in the process. We chose to work with the Adapteva Parallella boards and design a DSM system there. Over one semester we designed and developed that system.
|
|
| 33. |
- Bjerg, Anders, et al.
(författare)
-
Increased Prevalence of Symptoms of Rhinitis but Not of Asthma between 1990 and 2008 in Swedish Adults : Comparisons of the ECRHS and GA(2)LEN Surveys
- 2011
-
Ingår i: PLoS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 6:2, s. e16082-
-
Tidskriftsartikel (refereegranskat)abstract
- Background: The increase in asthma prevalence until 1990 has been well described. Thereafter, time trends are poorly known, due to the low number of high quality studies. The preferred method for studying time trends in prevalence is repeated surveys of similar populations. This study aimed to compare the prevalence of asthma symptoms and their major determinants, rhinitis and smoking, in Swedish young adults in 1990 and 2008. Methods: In 1990 the European Community Respiratory Health Survey (ECRHS) studied respiratory symptoms, asthma, rhinitis and smoking in a population-based sample (86% participation) in Sweden. In 2008 the same symptom questions were included in the Global Allergy and Asthma European Network (GA(2)LEN) survey (60% participation). Smoking questions were however differently worded. The regions (Gothenburg, Uppsala, Umea) and age interval (20-44 years) surveyed both in 1990 (n = 8,982) and 2008 (n = 9,156) were analysed. Results: The prevalence of any wheeze last 12 months decreased from 20% to 16% (p<0.001), and the prevalence of "asthma-related symptoms" was unchanged at 7%. However, either having asthma attacks or using asthma medications increased from 6% to 8% (p<0.001), and their major risk factor, rhinitis, increased from 22% to 31%. Past and present smoking decreased. Conclusion: From 1990 to 2008 the prevalence of obstructive airway symptoms common in asthma did not increase in Swedish young adults. This supports the few available international findings suggesting the previous upward trend in asthma has recently reached a plateau. The fact that wheeze did not increase despite the significant increment in rhinitis, may at least in part be due to the decrease in smoking.
|
|
| 34. |
|
|
| 35. |
- Blomquist, Nicklas, 1987-, et al.
(författare)
-
Large-Scale Production of Nanographite by Tube-Shear Exfoliation in Water
- 2016
-
Ingår i: PLOS ONE. - : Nicklas Blomquist. - 1932-6203. ; 11:4
-
Tidskriftsartikel (refereegranskat)abstract
- The number of applications based on graphene, few-layer graphene, and nanographite is rapidly increasing. A large-scale process for production of these materials is critically needed to achieve cost-effective commercial products. Here, we present a novel process to mechanically exfoliate industrial quantities of nanographite from graphite in an aqueous environment with low energy consumption and at controlled shear conditions. This process, based on hydrodynamic tube shearing, produced nanometer-thick and micrometer-wide flakes of nanographite with a production rate exceeding 500 gh-1 with an energy consumption about 10 Whg-1. In addition, to facilitate large-area coating, we show that the nanographite can be mixed with nanofibrillated cellulose in the process to form highly conductive, robust and environmentally friendly composites. This composite has a sheet resistance below 1.75 Ω/sq and an electrical resistivity of 1.39×10-4 Ωm and may find use in several applications, from supercapacitors and batteries to printed electronics and solar cells. A batch of 100 liter was processed in less than 4 hours. The design of the process allow scaling to even larger volumes and the low energy consumption indicates a low-cost process.
|
|
| 36. |
- Blomquist, Nicklas, 1987-, et al.
(författare)
-
Metal-free supercapacitor with aqueous electrolyte and low-cost carbon materials
- 2017
-
Ingår i: Scientific Reports. - : Nature Publishing Group. - 2045-2322. ; 7
-
Tidskriftsartikel (refereegranskat)abstract
- Electric double-layer capacitors (EDLCs) or supercapacitors (SCs) are fast energy storage devices with high pulse efficiency and superior cyclability, which makes them useful in various applications including electronics, vehicles and grids. Aqueous SCs are considered to be more environmentally friendly than those based on organic electrolytes. Because of the corrosive nature of the aqueous environment, however, expensive electrochemically stable materials are needed for the current collectors and electrodes in aqueous SCs. This results in high costs for a given energy-storage capacity. To address this, we developed a novel low-cost aqueous SC using graphite foil as the current collector and a mix of graphene, nanographite, simple water-purification carbons and nanocellulose as electrodes. The electrodes were coated directly onto the graphite foil by using casting frames and the SCs were assembled in a pouch cell design. With this approach, we achieved a material cost reduction of greater than 90% while maintaining approximately one-half of the specific capacitance of a commercial unit, thus demonstrating that the proposed SC can be an environmentally friendly, low-cost alternative to conventional SCs.
|
|
| 37. |
- Boman, Kurt, et al.
(författare)
-
Remote-controlled robotic arm for real-time echocardiography : the diagnostic future for patients in rural areas?
- 2009
-
Ingår i: Telemedicine journal and e-health. - : Mary Ann Liebert Inc. - 1530-5627 .- 1556-3669. ; 15:2, s. 142-147
-
Tidskriftsartikel (refereegranskat)abstract
- There exists a great clinical need for improving specialist consultation and utilization of echocardiography in areas remote from hospital-based care. This paper presents the development and first technical assessment of a concept of cardiovascular consultation utilizing long distance, real-time echocardiography as a diagnostic tool in rural areas. The development of CARdiological consultation at a DISTance (CARDISTA) was achieved in three stages, comprising tests of different broadband infrastructures, videoconference systems, microphones, cameras, monitors, and loudspeakers. The CARDISTA concept includes a cardiologist and a sonographer, a robotic arm (Medirob), a portable ultrasound machine, and presently available information technology using an advanced broadband backbone. The three stages provided, with some remaining doubts, echocardiographic examination at a distance comparable to hospital-based examinations. A continuous broadband capacity of 20 megabits per second (Mbps) seemed to be a vital component of CARDISTA for achieving the highest-quality imaging. With this broadband capacity, it was possible to achieve a transmission delay below 200 ms. The technical tests of the CARDISTA concept revealed promising results in enabling long distance real-time echocardiography for specialist consultation. CARDISTA is now ready for clinical testing and evaluation in rural areas for patients with heart diseases, especially heart failure.
|
|
| 38. |
- Cancer, Matko, et al.
(författare)
-
BET and Aurora Kinase A inhibitors synergize against MYCN-positive human glioblastoma cells
- 2019
-
Ingår i: Cell Death and Disease. - : NATURE PUBLISHING GROUP. - 2041-4889. ; 10
-
Tidskriftsartikel (refereegranskat)abstract
- Glioblastoma multiforme (GBM) is the most common primary malignant brain tumor in adults. Patients usually undergo surgery followed by aggressive radio- and chemotherapy with the alkylating agent temozolomide (TMZ). Still, median survival is only 12-15 months after diagnosis. Many human cancers including GBMs demonstrate addiction to MYC transcription factor signaling and can become susceptible to inhibition of MYC downstream genes. JQ1 is an effective inhibitor of BET Bromodomains, a class of epigenetic readers regulating expression of downstream MYC targets. Here, we show that BET inhibition decreases viability of patient-derived GBM cell lines. We propose a distinct expression signature of MYCN-elevated GBM cells that correlates with significant sensitivity to BET inhibition. In tumors showing JQ1 sensitivity, we found enrichment of pathways regulating cell cycle, DNA damage response and repair. As DNA repair leads to acquired chemoresistance to TMZ, JQ1 treatment in combination with TMZ synergistically inhibited proliferation of MYCN-elevated cells. Bioinformatic analyses further showed that the expression of MYCN correlates with Aurora Kinase A levels and Aurora Kinase inhibitors indeed showed synergistic efficacy in combination with BET inhibition. Collectively, our data suggest that BET inhibitors could potentiate the efficacy of either TMZ or Aurora Kinase inhibitors in GBM treatment.
|
|
| 39. |
|
|
| 40. |
- Dahlstedt, Magnus, et al.
(författare)
-
Systemet med fritt skolval måste bytas ut
- 2018
-
Ingår i: Svenska Dagbladet.
-
Tidskriftsartikel (populärvet., debatt m.m.)abstract
- Ökad segregation och deprofessionalisering av läraryrket är några av effekterna av det fria skolvalet. Nu krävs en grundlig utredning med siktet inställt på att hitta alternativ till nuvarande marknadssystem, skriver ett flertal forskare.
|
|
| 41. |
|
|
| 42. |
- Dalmo, Erika, et al.
(författare)
-
Targeting SOX2 in glioblastoma cells reveals heterogeneity in SOX2 dependency
-
Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Glioblastoma (GBM) is a lethal disease with no curative treatment. SOX2 is a stem cell transcription factor which is widely expressed across human GBM tumors. Downregulation of SOX2 inhibits tumor formation and its depletion leads to a complete stop of cell proliferation. Despite its known important role in GBM, there is a lack of SOX2 overexpression studies in human GBM cells cultured under stem cell conditions. Previous work in our lab suggests that SOX2 levels need to be precisely maintained for GBM cells to thrive. In this project, we have investigated how altered SOX2 expression affects primary human GBM lines. We found that elevated SOX2 expression inhibited proliferation in a dose-dependent manner in three out of four GBM cell lines. Global gene expression in the resistant line was shifted towards that of the proliferation-inhibited lines upon SOX2 induction. However, SOX2 induction also led to an increase in a GBM stem cell injury response phenotype, which was not present in proliferation-inhibited lines. Furthermore, CRISPR/Cas9-mediated SOX2 knockout revealed a SOX2 independence in the resistant cell line, where SOX2-negative cells could be propagated both in vitro and in vivo.
|
|
| 43. |
- Engqvist, Cecilia, et al.
(författare)
-
Interactions between single latex particles and silica surfaces studied with AFM
- 2007
-
Ingår i: Colloids and Surfaces A. - : Elsevier BV. - 0927-7757 .- 1873-4359. ; 302:03-jan, s. 197-203
-
Tidskriftsartikel (refereegranskat)abstract
- The spreading of single styrene-acrylic latex particles on silicon oxide C surfaces was studied using atomic force microscopy (AFM). Three latexes with different glass transition temperature (Tg) were used and the effects of temperature, time and preparation method were investigated. Particle sizes and shape were measured with AFM and the contact angles were calculated. The observed rate for the spreading of latex particles was low and it took several days before the particles reached steady state, even at temperatures well above their T-g. The experimental particle spreading results deviated with two orders of magnitude from predictions Using the WLF equation for polymer diffusion. The deviation could be attributed to polymer-surface interactions that slowed down the particle spreading. The work of adhesion was calculated using two models. The results from using the regular Young-Dupre equation and a modified version of this equation that also included the mechanical properties (E-modulus and Poisson's ratio) of the latexes, were compared. For soft latex particles the results from the two models agreed well and were of the order of 75 J/m(2), but for glassy latexes the Young-Dupre equation underestimated the work of adhesion.
|
|
| 44. |
- Fjellström, Helena, 1977-, et al.
(författare)
-
A novel method for studying the photo-stabilising properties of coating layers
- 2006
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- A new model system was developed which made it possible to study the reflectance and transmittance of thin coating layers (<10 g/m2) in a reproducible way, and to link this to the inhibition of the light-induced yellowing (Figure 1). The UV/VIS-screening properties of coatings of different coat weights containing common pigments such as kaolin, calcium carbonate (ground or precipitated) and titanium dioxide will be reported. The ability of a coating layer to protect a birch CTMP from light-induced discoloration will be exemplified using the evolved model system. An estimation of the contribution of different wavelength regions of the illuminating light to the photo-yellowing of various types of materials will also be shown. The developed method is a valuable tool for future photo-yellowing studies as well as for optimisation of the pigment coating formulation for various paper grades.
|
|
| 45. |
- Fjellström, Helena, et al.
(författare)
-
A novel method of studying the ability of coating layer to retard the photo-yellowing of the base paper
- 2007
-
Ingår i: Nordic Pulp & Paper Research Journal. - 0283-2631 .- 2000-0669. ; 22:3, s. 343-349
-
Tidskriftsartikel (refereegranskat)abstract
- A method was developed which made it possible to study the reflectance/transmittance of thin coating layers and to link this to the inhibition of the light-induced yellowing. The ability of a coating layer to retard the photo-yellowing of a hydrogen-peroxide-bleached birch chemithermomechanical pulp (CTMP) is exemplified using this method. It is shown that the repeatability of the model system is excellent, even for coat weights below 10 g/m2. Furthermore, the transmittance in the UV-region is strongly correlated with the coating layers ability to protect the birch CTMP against photo-yellowing.
|
|
| 46. |
- Fjellström, Helena, et al.
(författare)
-
Influence of coating formulation on light-induced brightness stability of mechanical and chemimechanical pulp sheets
- 2005
-
Ingår i: International Mechanical Pulping Conference: IMPC 2005, Oslo, Norway, 7-9 June 2005. ; , s. 339-343
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- The light-induced brightness reversion of different types of high-yield pulps has been studied under accelerated and long-term ambient ageing conditions. It was found that accelerated ageing (xenon lamp used as light source) overestimates the yellowing tendencies of hardwood pulps, whereas it was possible to predict the yellowing characteristics of softwood pulps. The lignin content of the pulps was found to be correlated to the degree of photo-yellowing for long-term ambient ageing. A model system was developed which made it possible to study the reflectance/transmittance of thin coating layers and to link this to the inhibition of the light-induced yellowing. The yellowing characteristics of a coated birch CTMP is exemplified using the evolved model system.
|
|
| 47. |
- Fjellström, Helena, et al.
(författare)
-
Inhibition of light-induced brightness reversion of high-yield pulps : the UV-screening properties of coating layers containing kaolin or calcium carbonate pigments
- 2007
-
Ingår i: Nordic Pulp & Paper Research Journal. - 0283-2631 .- 2000-0669. ; 22:3, s. 350-355
-
Tidskriftsartikel (refereegranskat)abstract
- A newly developed method making it possible to study the reflectance/transmittance of thin coating layers and to link this to the inhibition of the light-induced yellowing, was used to describe the photo-stabilising properties of different types of commercial kaolin and calcium carbonate pigments. A base paper produced from a hydrogen-peroxide-bleached birch chemithermomechanical pulp (CTMP) was used throughout the study.The transmittance of the coating layers in the UV-region (300-385 nm) was found to be very low (below 1.0% at coat weights < 5g/m2) for all of the tested pigments, it strongly depends on the coat weight especially for coat weights below 10 g/m2. The kaolin pigments examined were found to be better in inhibiting the brightness reversion compared to the calcium carbonate pigments, even though the differences between the pigment types were only a few brightness units. The coating layer was, however, able to conceal some of the colour formed through the light-induce brightness reversion. For example, a coating layer consisting of kaolin pigments (coat weight of 15.6 g/m2) could conceal about 30% of the discoloration of the CTMP base paper.
|
|
| 48. |
- Fjellström, Helena, et al.
(författare)
-
The UV-screening properties of coating layers : The influence of pigments, binders and additives
- 2009
-
Ingår i: Nordic Pulp & Paper Research Journal. - 0283-2631 .- 2000-0669. ; 24:2, s. 206-212
-
Tidskriftsartikel (refereegranskat)abstract
- The ability of coating colours to obstruct ultraviolet (UV) radiation in the 300-385 nm region was examined with the aim of finding the best photo-stabilising formulation to inhibit discoloration of high-yield pulps. The influence of pigment type, bleaching of the pigments, pigment size, pigment size distribution, type of binder and addition of U-V-absorbing compounds were examined using a newly developed method for studying the reflectance and transmittance properties of thin coating layers.The pigment type and coat weight was found to be the most important factors for reducing the transmittance of UV-radiation. Kaolin clays were more effective than calcium carbonate pigments and are therefore a better coating pigment for photostability reasons. Bleaching of the pigments, resulted in an overall minor decrease in transmittance for both kaolin and ground calcium carbonate (GCC) pigments, especially at low coat weights. Bleaching of the pigments changed the particle size distribution somewhat, which probably alters the structure in the coating layer. Precipitated calcium carbonate (PCC) pigments have a higher UV-screening potential compared to GCC pigments and should therefore be a better choice among the calcium carbonates. It was further concluded that a narrow pigment size distribution was beneficial for reducing the amount of transmitted UV-radiation that reaches the base paper. Styrene butadiene latex and polyvinylpyrrolidone were better in reducing the transmittance in the UV-region than polyvinyl alcohol.Adding a fluorescent whitening agent to a coating colour decreased the transmittance in the UV-region when the pigment was of the GCC type, and increased the transmittance when kaolin pigment was used. Addition of titanium dioxide (3 parts) to a coating colour containing kaolin pigment blocked about 90% of the UV-radiation at a coat weight of 10 g/m(2), which is a common coat weight for a single coated paper. Another possibility is to double coat to increase the coat weight, which turns the transmittance factor closed to zero.
|
|
| 49. |
- Forsberg, Anna, et al.
(författare)
-
Once-only colonoscopy or two rounds of faecal immunochemical testing 2 years apart for colorectal cancer screening (SCREESCO): preliminary report of a randomised controlled trial
- 2022
-
Ingår i: The Lancet Gastroenterology & Hepatology. - : ELSEVIER INC. - 2468-1253. ; 7:6, s. 513-521
-
Tidskriftsartikel (refereegranskat)abstract
- Background Screening for colorectal cancer is done with lower gastrointestinal endoscopy or stool-based tests. There is little evidence from randomised trials to show primary colonoscopy reduces mortality in colorectal cancer We aimed to investigate the effect of screening with once-only colonoscopy or two rounds of faecal immunochemical test screening on colorectal cancer mortality and incidence. Methods We did a randomised controlled trial in Sweden (SCREESCO). Residents in 18 of 21 regions who were age 60 years in the year of randomisation were identified from a population register maintained by the Swedish Tax Agency. A statistician with no further involvement in the trial used a randomised block method to assign individuals to once-only colonoscopy, two rounds of faecal immunochemical testing (OC-Sensor; 2 years apart), or a control group (no intervention; standard diagnostic pathways), in a ratio of 1:6 for colonoscopy versus control and 1:2 for faecal immunochemical testing versus control. Masking was not possible due to the nature of the trial. The primary endpoints of the trial are colorectal cancer mortality and colorectal cancer incidence. Here, we report preliminary participation rates, baseline findings, and adverse events from March, 2014, to December, 2020, in the two intervention groups after completion of recruitment and screening, up to the completion of the second faecal immunochemical testing round. Analyses were done in the intention-to-screen population, defined as all individuals who were randomly assigned to the respective study group. This study is registered with Clinical Trials.gov, NCT02078804. Findings Between March 1, 2014, and Dec 31, 2020, 278 280 people were induded in the study; 31 140 were assigned to the colonoscopy group, 60 300 to the faecal immunochemical test group, and 186 840 to the control group. 10 679 (35.1%) of 30 400 people who received an invitation for colonoscopy participated. 33 383 (55.5%) of 60 137 people who received a postal faecal immunochemical test participated. In the intention-to-screen analysis, colorectal cancer was detected in 49 (0.16%) of 31140 people in the colonoscopy group versus 121 (0. 20%) of 60 300 in the faecal immunochemical test group (relative risk [RR] 0.78, 95% CI 0.56-1.09). Advanced adenomas were detected in 637 (2.05%) people in the colonoscopy group and 968 (1.61%) in the faecal immunochemical test group (RR 1.27, 95% CI 1.15-1.41). Colonoscopy detected more right-sided advanced adenomas than faecal immunochemical testing. There were two perforations and 15 major bleeds in 16 555 colonoscopies. No intervention-related deaths occurred. Interpretation The diagnostic yield and the low number of adverse events indicate that the design from this trial, both for once-only colonoscopy and faecal immunochemical test screening, could be transferred to a population-based screening service if a benefit in disease-specific mortality is subsequently shown. Copyright (C) 2022 Elsevier Ltd. All rights reserved.
|
|
| 50. |
|
|
