| 1. |
- Andersson, Henrik, et al.
(författare)
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T A microarray analysis of the murine macrophage response to infection with Francisella tularensis LVS
- 2006
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Ingår i: Journal of Medical Microbiology. - : Microbiology Society. - 0022-2615 .- 1473-5644. ; 55:8, s. 1023-1033
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Tidskriftsartikel (refereegranskat)abstract
- The response of cells of the mouse macrophage cell line J774 to infection with Francisella tularensis LVS was analysed by means of a DNA microarray representing approximately 18 500 genes (20 600 clones). The adaptive response was modest at all time points, and at most, 81 clones were differentially regulated from the time point of uptake of bacteria (0 min) up to 240 min later. For all five time points, 229 clones fulfilled the criteria of being differentially regulated, i.e. the ratio between infected versus non-infected cells was at least 1.7-fold up- or down-regulated and P <0.05. It was found that many of the differentially regulated genes are known to respond to stress in general and to oxidative stress specifically. However, at 120 min it was observed that genes that lead to depletion of glutathione were upregulated. Possibly, this was a result of mechanisms induced by F. tularensis. Generally, there was a conspicuous lack of inflammatory responses and, for example, although tumour necrosis factor alpha (TNF-α) was upregulated at 0 min, a significant down-regulation was noted at all subsequent time points. When cells were treated with an inhibitor of inducible nitric oxide synthase (iNOS) or the antioxidant N-acetylcysteine (NAC), the infection-induced cytopathogenic effect was significantly inhibited. Together, the results suggest that F. tularensis LVS infection confers an oxidative stress upon the target cells and that many of the host-defence mechanisms appear to be intended to counteract this stress. The infection is characterized by a very modest inflammatory response.
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| 2. |
- Andersson, Mattias, et al.
(författare)
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Intrinsic and extrinsic influences on the temperature dependence of mobility in conjugated polymers
- 2008
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Ingår i: Organic electronics. - : Elsevier. - 1566-1199 .- 1878-5530. ; 9:5, s. 569-574
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Tidskriftsartikel (refereegranskat)abstract
- The temperature dependence of charge carrier mobility in conjugated polymers and their blends with fullerenes is investigated with different electrical methods, through field effect transistor (FET), space charge limited current (SCLC) and charge extraction (CELIV) measurements. Simple models, such as the Gaussian disorder model (GDM), are shown to accurately predict the temperature behavior, and a good correlation between the different measurement methods is obtained. Inconsistent charge carrier concentrations in the modeling are explained through intrinsic non-equilibrium effects, and are responsible for the limited applicability of existing numerical models. A severe extrinsic influence from water in FETs with a hydrophilic insulator interface is also demonstrated. The presence of water leads to a significant overestimate of the disorder in the materials from measurements close to room temperature and erratic behavior in the 150-350 K range. To circumvent this problem it is shown to be necessary to measure under ultra high vacuum (UHV) conditions. © 2008 Elsevier B.V. All rights reserved.
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| 3. |
- Andersson, Mattias K., et al.
(författare)
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The extended substrate cleavage specificity of the human mast cell chymase reveals a serine protease with well-defined substrate recognition profile
- 2009
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Ingår i: International Immunology. - : Oxford University Press (OUP). - 0953-8178 .- 1460-2377. ; 21:1, s. 95-104
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Tidskriftsartikel (refereegranskat)abstract
- The human chymase (HC) is a major granule constituent of mast cells (MCs) residing in the connective tissue and the sub-mucosa. Although many potential substrates have been described for this important MC enzyme, its full range of in vivo substrates has most likely not yet been identified. A major step toward a better understanding of the function of the HC is therefore to determine its extended cleavage specificity. Using a phage-displayed random nonapeptide library, we show that the HC has a rather stringent substrate recognition profile. Only aromatic amino acids (aa) are accepted in position P1, with a strong preference for Tyr and Phe over Trp. Aliphatic aa are preferred in positions P2 to P4 N-terminal of the cleaved bond. In the P1' position C-terminal of the cleaved bond, Ser is clearly over-represented and acidic aa Asp and Glu are strongly preferred in the P2' position. In P3', the small aliphatic aa Ala, Val and Gly were frequently observed. The consensus sequence, from P4 to P3': Gly/Leu/Val-Val/Ala/Leu-Ala/Val/Leu-Tyr/Phe-Ser-Asp/Glu-Ala/Val/Gly, provides an instrument for the identification of novel in vivo substrates for the HC. Interestingly, a very similar cleavage specificity was recently reported for the major chymase in mouse connective tissue mast cells (CTMCs), the beta-chymase mouse mast cell protease-4, suggesting functional homology between these two enzymes. This indicates that a rather stringent chymotryptic substrate recognition profile has been evolutionary conserved for the dominant CTMC chymase in mammals.
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| 4. |
- Andersson, Marcus, 1975, et al.
(författare)
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Quartz crystal microbalance-with dissipation monitoring (QCM-D) for real time measurements of blood coagulation density and immune complement activation on artificial surfaces
- 2005
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Ingår i: Biosensors & Bioelectronics. - : Elsevier BV. - 0956-5663. ; 21:1, s. 79-86
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Tidskriftsartikel (refereegranskat)abstract
- A recently developed variant of quartz crystal microbalance (QCM) called QCM-with dissipation monitoring (QCM-D) allows simultaneous and simple measurements of changes in adsorbed mass as well as the viscoelastic property (D-factor) of deposited protein layers on the sensor surface. We have taken the QCM-D technology a step further and demonstrated its advantages in the study of protein assembly as a consequence of surface induced immune complement activation, or contact activated blood coagulation. In the present study we have continued our QCM-D investigations of surface assembly of fibrin clot formation and complement activation and incubated differently modified quartz sensor surfaces in blood plasma and sera. Polymer surfaces used were spin-coated polyethylene, poly(ethylene terephtalate), poly(methylmetacrylate) and poly(dimethylsiloxane). Also used were sputtered titanium and heparin grafted surfaces. In this investigation we found that we could describe the surface induced coagulation with four independent parameters: (1) Time of onset of coagulation, (2) fibrin deposition rate, (3) total frequency shift at stable plateau, and (4) fibrin clot density. The most important finding was that the blood plasma clot density can be assessed with the use of D determinations and that the clot density varied significantly with the chemical composition of the surface. However, the D-factor did not give any new analytical information about the possible complement activation mechanisms. Nevertheless, the QCM-D was found to be a reliable tool for the analysis of surface induced complement activation. We also compared the QCM-D technique with traditional enzyme immuno assay (EIA) measurements of soluble products from the surface activation of the complement and coagulation systems. We found that the results from EIA and QCM-D measurements corresponded well for the complement activation but not for the coagulation, probably due to the biological complexity of the coagulation system.
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| 5. |
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| 6. |
- Arvidsson, Yvonne, 1960, et al.
(författare)
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Amyloid precursor-like protein 1 is differentially upregulated in neuroendocrine tumours of the gastrointestinal tract.
- 2008
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Ingår i: Endocrine-related cancer. - 1351-0088. ; 15:2, s. 569-81
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Tidskriftsartikel (refereegranskat)abstract
- We have examined the global gene expression profile of small intestinal carcinoids by microarray analysis. High expression of a number of genes was found including amyloid precursor-like protein 1 (APLP1). Quantitative real-time PCR and western blot analysis demonstrated higher expression of APLP1 in carcinoid metastases relative to primary tumours indicating a role of APLP1 in tumour dissemination. Tissue microarray analysis of gastroentero-pancreatic tumours demonstrated a high frequency of APLP1 expression and a low frequency of APLP2 expression in neuroendocrine (NE) tumours when compared with non-NE tumours at the same sites. Meta-analysis of gene expression data from a large number of tumours outside the gastrointestinal tract confirmed a correlation between APLP1 expression and NE phenotype where high expression of APLP1 was accompanied by downregulation of APLP2 in NE tumours. Cellular localization of APLP1, APLP2 and amyloid precursor protein (APP) in carcinoid cells (GOT1) by confocal microscopy demonstrated partial co-localization with synaptophysin. This suggests that the APP family of proteins is transported to the cell membrane by synaptic microvesicles and that they may influence tumour cell adhesion and invasiveness. We conclude that APLP1 is differentially upregulated in gastrointestinal NE tumours and that APLP1 may be important for the dissemination of small intestinal carcinoids. Identification of APLP1 in NE tumours offers a novel target for treatment and may also serve as a tumour-specific marker.
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| 7. |
- Chen, Miaoxiang, 1962-, et al.
(författare)
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High carrier mobility in low band gap polymer-based field-effect transistors
- 2005
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Ingår i: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 87:25, s. 252105-1-252105-3
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Tidskriftsartikel (refereegranskat)abstract
- A conjugated polymer with a low band gap of 1.21 eV, i.e., absorbing infrared light, is demonstrated as active material in field-effect transistors (FETs). The material consists of alternating fluorene units and low band gap segments with electron donor-acceptor-donor units composed of two electron-donating thiophene rings attached on both sides of a thiadiazolo-quinoxaline electron-acceptor group. The polymer is solution-processable and air-stable; the resulting FETs exhibit typical p-channel characteristics and field-effect mobility of 0.03 cm2 V−1 s−1.
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| 8. |
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| 9. |
- Gadisa, Abay, et al.
(författare)
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A new donor-acceptor-donor polyfluorene copolymer with balanced electron and hole mobility
- 2007
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Ingår i: Adv. Funct. Mater. FIELD Full Journal Title:Advanced Functional Materials. ; 17:18, s. 3836-3842
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Tidskriftsartikel (refereegranskat)abstract
- A new alternating polyfluorene copolymer poly[2,7-(9,9-dioctylfluoren)-alt-5,5-(5',8'-di-2-thienyl-(2',3'-bis-(3''-octyloxyphenyl)-quinoxaline))] (APFO-15), which has electron donor-acceptor-donor units in between the fluorene units, is synthesized and characterized. This polymer has a strong absorption and emission in the visible range of the solar spectrum. Its electroluminescence and photolumin escence emissions extend from about 560 to 900 nm. Moreover, solar cells with efficiencies in excess of 3.5 % have been realized from blends of APFO-15 and an electron acceptor mol., a mathanofullerene [6,6]-phenyl-C61-butyric acid Me ester (PCBM). It has also been obsd. that electron and hole transport is balanced both in the pure polymer phase and in polymer/PCBM bulk heterojunction films, which makes this material quite attractive for applications in opto-electronic devices. [on SciFinder (R)]
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| 10. |
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| 11. |
- Göransson, Melker, 1974, et al.
(författare)
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The myxoid liposarcoma FUS-DDIT3 fusion oncoprotein deregulates NF-kappaB target genes by interaction with NFKBIZ.
- 2009
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Ingår i: Oncogene. - : Springer Science and Business Media LLC. - 1476-5594 .- 0950-9232. ; 28:2, s. 270-8
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Tidskriftsartikel (refereegranskat)abstract
- FUS (also called TLS), EWSR1 and TAF15 (also called TAF2N) are related genes involved in tumor type-specific fusion oncogenes in human malignancies. The FUS-DDIT3 fusion oncogene results from a t(12;16)(q13;p11) chromosome translocation and has a causative role in the initiation of myxoid/round cell liposarcomas (MLS/RCLS). The FUS-DDIT3 protein induces increased expression of the CAAT/enhancer-binding protein (C/EBP) and nuclear factor-kappaB (NF-kappaB)-controlled gene IL8, and the N-terminal FUS part is required for this activation. Chromatin immunoprecipitation analysis showed that FUS-DDIT3 binds the IL8 promoter. Expression studies of the IL8 promoter harboring a C/EBP-NF-kappaB composite site pinpointed the importance of NF-kappaB for IL8 expression in FUS-DDIT3-expressing cells. We therefore probed for possible interaction of FUS-DDIT3 with members of the NF-kappaB family. The nuclear factor NFKBIZ colocalizes with FUS-DDIT3 in nuclear structures, and immunoprecipitation experiments showed that FUS-DDIT3 binds the C-terminal of NFKBIZ. We also report that additional NF-kappaB-controlled genes are upregulated at the mRNA level in FUS-DDIT3-expressing cell lines and they can be induced by NFKBIZ. Taken together, the results indicate that FUS-DDIT3 deregulates some NF-kappaB-controlled genes through interactions with NFKBIZ. Similar mechanisms may be a part of the transformation process in other tumor types carrying FUS, EWSR1 and TAF15 containing fusion oncogenes.
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| 12. |
- Lindgren, Lars Johan, 1977, et al.
(författare)
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Synthesis, Characterization, and Devices of a Series of Alternating Copolymers for Solar Cells
- 2009
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Ingår i: CHEMISTRY OF MATERIALS. - : American Chemical Society (ACS). - 0897-4756 .- 1520-5002. ; 21:15, s. 3491-3502
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Tidskriftsartikel (refereegranskat)abstract
- In this study we report the synthesis, characterization. and photovoltaic properties of a series of six Conjugated polymers based on donor-acceptor-donor (DAD) structure. The polymers are obtained via Suzuki polymerization of different alkoxy-substituted DAD monomers together with a substituted fluorene or phenylene monomer. Application of polymers as light-harvesting and electron-donating materials in solar cells, in conjunction with both [60]PCBM and [70]PCBM as acceptors, show power-conversion efficiencies (PCEs) up to 2.9%, values obtained without extensive optimization work. Furthermore, atomic force microscopy and field-effect transistor (FET) mobility measurements of acceptor-polymer mixtures show that differences in substitution on the polymers affect morphology, mobility, and device performance. Within the series of polymers, all showing similar optical absorption and redox behavior, substituents play an important role in phase separation on a micrometer scale, which in turn has a large impact on device performance. The phase-separation behavior is clearly seen in [70]PCBM devices where the best-performing devices are obtained using the polymers with short alkoxy groups or no substituents together with a high speed of spin coating during device preparation.
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| 13. |
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| 14. |
- Rydell, Bengt, et al.
(författare)
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Geotechnical decision basis for sustainable coastal areas
- 2008
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Ingår i: [Host publication title missing]. - 9788360261071
-
Konferensbidrag (refereegranskat)abstract
- There are several urban areas close to the coast or other waterways that may be adversely affected by erosion, flooding and slope instability. Global climate change including sea level rise, increased precipitation and more intense and damaging storms will increase the threats of natural hazards in several areas. Mitigating and adapting to these risks in urban areas are huge challenges for society. There is a need for a proper geotechnical decision basis to build a long-term sustainable society in terms of economic, social and environmental aspects. By incorporating coastal hazard and risk mapping into spatial planning new developments can be diverted away from threatened areas and by adaptation measures risks in existing urban areas can be reduced.
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| 15. |
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| 16. |
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| 17. |
- Sudow, Mattias, 1980, et al.
(författare)
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A Single-Ended Resistive $X$-Band AlGaN/GaN HEMT MMIC Mixer
- 2008
-
Ingår i: IEEE Transactions on Microwave Theory and Techniques. - 0018-9480 .- 1557-9670. ; 56:10, s. 2201-2206
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Tidskriftsartikel (refereegranskat)abstract
- A broadband highly linear X-band mixer in AlGaN/GaN monolithic microwave integrated circuit technology has been designed, processed, and characterized. The design is based on a 4 times 100 mum AlGaN/GaN HEMT in a single-ended circuit topology. The mixer has an IF bandwidth of 2 GHz with a conversion loss (CL) of
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| 18. |
- Sudow, Mattias, 1980, et al.
(författare)
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An AlGaN/GaN HEMT-Based Microstrip MMIC Process for Advanced Transceiver Design
- 2008
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Ingår i: IEEE Transactions on Microwave Theory and Techniques. - 0018-9480 .- 1557-9670. ; 56:8, s. 1827-1833
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Tidskriftsartikel (refereegranskat)abstract
- A MMIC process in AlGaN/GaN technology for advanced transceiver design has been developed. The process is based on microstrip technology with a complete model library of passive elements and AlGaN/GaN HEMTs. The transistor technology in this process is suitable for both power and low noise design, demonstrated with a power density of 5 W/mm, and an ${rm NF}_{min}$ of 1.4 dB at $X$ -band. Process stability of subcircuits, complementary to power amplifiers and LNAs, in a transceiver system have been investigated. The results indicate that an all AlGaN/GaN MMIC transceiver is realizable using this technology.
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| 19. |
- Sudow, Mattias, 1980, et al.
(författare)
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SiC varactors for dynamic load modulation of high power amplifiers
- 2008
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Ingår i: IEEE Electron Device Letters. - 0741-3106 .- 1558-0563. ; 29:7, s. 728-730
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Tidskriftsartikel (refereegranskat)abstract
- SiC Schottky diode varactors with a high breakdown voltage, a high tuning ratio, and a low series resistance have been designed and fabricated. These characteristics are particularly necessary for the dynamic load modulation of high power amplifiers (PAs), which is an attractive alternative to other efficiency enhancement techniques. For a SiC Schottky diode varactor with a 50-µm radius fabricated by using a graded doping profile, a breakdown voltage of 40 V, a tuning range of 5.6, and a series resistance of 0.9 O were achieved. The results show the great potential of this type of varactors for the use in the dynamic load modulation of high power amplifiers. © 2008 IEEE.
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| 20. |
- Thorsell, Mattias, 1982, et al.
(författare)
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Characterization of the temperature dependent access resistances in AlGaN/GaN HEMTs
- 2008
-
Ingår i: Workshop on Integrated Nonlinear Microwave and Millimetre-Wave Circuits, 2008. INMMIC 2008.. - 9781424426454 ; , s. 17-20
-
Konferensbidrag (refereegranskat)abstract
- The temperature dependence of the access resistances for AlGaN/GaN HEMTs is investigated. The self-heating is measured using infrared microscopy and the access resistances are extracted at different ambient temperatures. Their influence on the intrinsic small signal parameters is studied versus bias and ambient temperature.
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| 21. |
- Thorsell, Mattias, 1982, et al.
(författare)
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Thermal characterization of the intrinsic noise parameters for AlGaN/GaN HEMTs
- 2008
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Ingår i: International Microwave Symposium Digest, 2008, Atlanta. - 0149-645X. - 9781424417810 ; , s. 463-466
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Konferensbidrag (refereegranskat)abstract
- The noise parameters of AlGaN/GaN-HEMTs are measured between 298 K and 423 K. The temperature dependent access resistances are de-embedded and the intrinsic noise parameters are studied as a function of temperature. It is shown that the parasitic access resistances are limiting the highfrequency noise performance of the AlGaN/GaN-HEMT.The intrinsic noise sources are extracted and a noise model is derived and verified for a MMIC amplifier.
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| 22. |
- Thorsell, Mattias, 1982, et al.
(författare)
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Thermal Study of the High-Frequency Noise in GaN HEMTs
- 2009
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Ingår i: IEEE Transactions on Microwave Theory and Techniques. - 0018-9480 .- 1557-9670. ; 57:1, s. 19-26
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Tidskriftsartikel (refereegranskat)abstract
- The high-frequency noise performance of the GaN HEMT is studied for temperatures between 297–398 K. The access resistances ${ R}_{ S}$ and ${ R}_{ D}$ have a limiting effect on the noise performance, and in this paper, their temperature dependence is studied in detail for a ${hbox{2}}times {hbox{100}} mu{hbox{m}}$ GaN HEMT. ${ R}_{ S}$ and ${ R}_{ D}$ show an increase of 0.71 and 0.86 %/K, respectively. The self-heating effect due to dissipated power is also studied to allow accurate intrinsic small-signal and noise parameter extraction. The thermal resistance is measured by infrared microscopy. Based on these results, a temperature dependent noise model including self-heating and temperature-dependent access resistances is derived and verified with measurements.
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| 23. |
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| 24. |
- Aarnio, Harri, et al.
(författare)
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Recombination studies in a polyfluorene copolymer for photovoltaic applications
- 2005
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Ingår i: Synthetic Metals. - : Elsevier BV. - 0379-6779. ; 155:2, s. 299-302
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Tidskriftsartikel (refereegranskat)abstract
- We present detailed continuous wave (cw) and transient photoinduced absorption (PA) measurements in thin films of a novel alternating polyfluorene copolymer, poly[2,7-(9,9-dioctyl-fluorene)-alt-5,5-(4',7'-di-2-thienyl-2',1',3-benzo-thiadiazole)] (DiO-PFDTBT), and its blends with the sol. fullerene deriv. [6,6]-phenyl-C61-butyric acid Me ester (PCBM) in wt. ratios of 1:0, 4:1 and 1:4. We measure the frequency, intensity and temp. dependence of the PA signal in the frequency domain, and compare with the results obtained from the transient PA decay measurements in the time domain. In all blends, the PA spectrum shows a broad high energy PA band ranging from .apprx.1 eV to 2 eV as well as a low energy band peaking at .apprx.0.35 eV. We attribute the low energy band to the P1 transition of polarons and part of the high energy band to the correlated P2 transition of polarons. Both frequency and time domain measurements show that the high energy band has two decay components, a faster component in the microsecond time regime and a slower component in the millisecond time regime. The slow component is strongly dispersive, whereas the fast component is practically non-dispersive. [on SciFinder (R)]
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| 25. |
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| 26. |
- Admassie, Shimelis, et al.
(författare)
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A polymer photodiode using vapour-phase polymerized PEDOT as an anode
- 2006
-
Ingår i: Solar Energy Materials & Solar Cells. ; 90:2, s. 133-141
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Tidskriftsartikel (refereegranskat)abstract
- We report the photovoltaic properties of devices made using a highly conducting polymer electrode, from vapor-phase polymd. poly (3,4-ethylenedioxy) thiophene (VPP PEDOT) on glass substrate as an anode and a polyfluorene copolymer poly[2,7-(9,9-dioctyl-fluorene)-alt-5,5-(4',7'-di-2thienyl-2',1'3'-benzothiadiazole)] (APFO-3) mixed with [6,6]-phenyl-C61-butyric acid methylester (PCBM) in the ratio of 1:4 as the active layer. The device performance was compared with that of devices made with PEDOT-PSS on glass substrates. The surfaces of VPP PEDOT were imaged using at. force microscopy (AFM). [on SciFinder (R)]
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| 27. |
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| 28. |
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| 29. |
- Andersson, Anna, et al.
(författare)
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Gene expression profiling of leukemic cell lines reveals conserved molecular signatures among subtypes with specific genetic aberrations
- 2005
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Ingår i: Leukemia. - : Springer Science and Business Media LLC. - 1476-5551 .- 0887-6924. ; 19:6, s. 1042-1050
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Tidskriftsartikel (refereegranskat)abstract
- Hematologic malignancies are characterized by fusion genes of biological/clinical importance. Immortalized cell lines with such aberrations are today widely used to model different aspects of leukemogenesis. Using cDNA microarrays, we determined the gene expression profiles of 40 cell lines as well as of primary leukemias harboring 11q23/MLL rearrangements, t(1;19)[TCF3/PBX1], t(12;21)[ETV6/RUNX1], t(8;21)[RUNX1/CBFA2T1], t(8;14) [IGH@/MYC], t(8;14)[TRA@/MYC], t(9;22)[BCR/ABL1], t(10;11) [PICALM/MLLT10], t(15;17)[PML/RARA], or inv(16)[CBFB/MYH11]. Unsupervised classification revealed that hematopoietic cell lines of diverse origin, but with the same primary genetic changes, segregated together, suggesting that pathogenetically important regulatory networks remain conserved despite numerous passages. Moreover, primary leukemias cosegregated with cell lines carrying identical genetic rearrangements, further supporting that critical regulatory pathways remain intact in hematopoietic cell lines. Transcriptional signatures correlating with clinical subtypes/primary genetic changes were identified and annotated based on their biological/molecular properties and chromosomal localization. Furthermore, the expression profile of tyrosine kinase-encoding genes was investigated, identifying several differentially expressed members, segregating with primary genetic changes, which may be targeted with tyrosine kinase inhibitors. The identified conserved signatures are likely to reflect regulatory networks of importance for the transforming abilities of the primary genetic changes and offer important pathogenetic insights as well as a number of targets for future rational drug design.
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| 30. |
- Andersson, Anna, et al.
(författare)
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Microarray-based classification of a consecutive series of 121 childhood acute leukemias: prediction of leukemic and genetic subtype as well as of minimal residual disease status.
- 2007
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Ingår i: Leukemia. - : Springer Science and Business Media LLC. - 1476-5551 .- 0887-6924. ; 21:6, s. 1198-1203
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Tidskriftsartikel (refereegranskat)abstract
- Gene expression analyses were performed on 121 consecutive childhood leukemias (87 B-lineage acute lymphoblastic leukemias (ALLs), 11 T-cell ALLs and 23 acute myeloid leukemias (AMLs)), investigated during an 8-year period at a single center. The supervised learning algorithm k-nearest neighbor was utilized to build gene expression predictors that could classify the ALLs/AMLs according to clinically important subtypes with high accuracy. Validation experiments in an independent data set verified the high prediction accuracies of our classifiers. B-lineage ALLs with uncharacteristic cytogenetic aberrations or with a normal karyotype displayed heterogeneous gene expression profiles, resulting in low prediction accuracies. Minimal residual disease status (MRD) in T-cell ALLs with a high (40.1%) MRD at day 29 could be classified with 100% accuracy already at the time of diagnosis. In pediatric leukemias with uncharacteristic cytogenetic aberrations or with a normal karyotype, unsupervised analysis identified two novel subgroups: one consisting mainly of cases remaining in complete remission (CR) and one containing a few patients in CR and all but one of the patients who relapsed. This study of a consecutive series of childhood leukemias confirms and extends further previous reports demonstrating that global gene expression profiling provides a valuable tool for genetic and clinical classification of childhood leukemias.
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| 31. |
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| 32. |
- Andersson, Ing-Marie, et al.
(författare)
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Arbetsmiljöfrågans väg : samverkan mellan kundföretag och företagshälsovård
- 2006
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Inom ramen för Tema SMARTA vid Arbetslivsinstitutet har ett delprojekt genomförts som utgår från frågan ”Hur kan och bör arbetsmiljöarbete bedrivas och integreras i organisationers verksamheter?”. Syftet är dels att analysera beslutsprocesser i arbetsmiljöfrågor i ett perspektiv av företagens kundrelation till ett företagshälsovårdsföretag (FHV-företag), dels att analysera hur en expertfunktion inom FHV – i det här fallet ergonomer – arbetar, särskilt avseende samverkan med kunden, metoder och verktyg. En bas för studien är genomgången av tidigare forskning inom området. Utöver detta baseras studien på intervjuer med FHV-företagens kunder och med ergonomer yrkesverksamma inom FHV, både interna och externa, samt med fristående ergonomikonsulter. Intervjuerna har berört beslutsprocesser, prioriteringar, initiativ och strukturer för ett förebyggande arbetsmiljöarbete samt systematiskt arbetsmiljöarbete. De har genomförts med kontaktpersoner på företag som är kunder till ett FHV-företag samt med ergonomer inom FHV som har intervjuats om vilka arbetssätt de väljer samt vilka metoder och verktyg de använder. Resultaten visar att beslutsprocessen är komplex och prioriteringar sker i många steg. I sitt arbete med arbetsmiljöfrågor vill företagen ofta själva prova att lösa olika problem, och gör också sådana försök, innan man tar kontakt med sitt FHVföretag. Alla yrkeskategorier inom FHV-företaget anlitas men oftast en i taget, snarare än som ett samlat team. Företagen litar på FHV-företagens rekommendationer, men genomför till stor del åtgärderna på egen hand och utan att utvärdera resultaten. Många ergonomer fungerar som experter och som i sina uppdrag använder få eller enstaka metoder samt analyserar och levererar lösningar. Relationen mellan FHV-företaget och kunden bygger i liten omfattning på arbetsformer som innehåller dialog och en metodik som innebär ett gemensamt problemlösningsarbete.
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| 33. |
- Andersson, Kristoffer, 1976, et al.
(författare)
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Fabrication and characterization of field-plated buried-gate SiC MESFETs
- 2006
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Ingår i: IEEE Electron Device Letters. - 0741-3106 .- 1558-0563. ; 27:7, s. 573-575
-
Tidskriftsartikel (refereegranskat)abstract
- Silicon carbide (SiC) MESFETs were fabricated using a standard SiC MESFET structure with the application of the "buried-channel" and field-plate (FP) techniques in the process. FPs combined with a buried-gate are shown to be favorable concerning output power density and power-added efficiency (PAE), due to higher breakdown voltage and decreased output conductance. A very high power density of 7.8 W/mm was measured on-wafer at 3 GHz for a two-finger 400-/spl mu/m gate periphery SiC MESFET. The PAE for this device was 70% at class AB bias. Two-tone measurements at 3 GHz /spl plusmn/ 100 kHz indicate an optimum FP length for high linearity operation.
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| 34. |
- Andersson, Lars Mattias, et al.
(författare)
-
Acceptor influence on hole mobility in fullerene blends with alternating copolymers of fluorene
- 2006
-
Ingår i: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 88, s. 082103-
-
Tidskriftsartikel (refereegranskat)abstract
- Hole mobility in polyfluorene/fullerene blends has been studied with field effect transistors. Two different C60 derivatives and one C70 derivative have been investigated together with two different polyfluorenes. Mobility is presented as a function of acceptor loading at ratios suitable for photovoltaics and varies between 10–3 and 10–5 cm2 V–1 s–1 depending on the polymer/acceptor combination. The hole mobility is increased in blends with the commonly used acceptor [6-6]-phenyl-C61-butyric acid methylester (PCBM). With related C60 and C70 derivatives the hole mobility is decreased under the same circumstances.
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| 35. |
- Andersson, Lars Mattias, et al.
(författare)
-
Bipolar transport observed through extraction currents on organic photovoltaic blend materials
- 2006
-
Ingår i: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 89, s. 142111-
-
Tidskriftsartikel (refereegranskat)abstract
- Both electron and hole mobilities have been simultaneously measured through charge extraction by linearly increasing voltage on polymer heterojunction solar cells with varying stoichiometry of polymer and acceptor. The polymer is a low band gap copolymer of fluorene, thiophene, and electron accepting groups named APFO-Green 5, and the acceptor is [6,6]-phenyl-C61-butyric acid methylester. Results are correlated to field effect transistor measurements on the same material system. A monotonous increase in mobility for both carrier types is observed with increased acceptor loading.
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| 36. |
- Andersson, Lars Mattias, 1976-
(författare)
-
Electronic Transport in Polymeric Solar Cells and Transistors
- 2007
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The main topic of this dissertation is electronic charge transport in polymeric and molecular organic materials and material blends intended for solar cell applications. Charge transport in polymers is a strange beast and carrier mobility is rarely a well-defined number. Measurements on different sample geometries and under different conditions tend to give different results and when everything is to be related to solar cell performance it is imperative that there is a way to correlate the results from different measurements. Polymer solar cells utilize composite materials for their function. This puts an additional twist on charge transport studies, as there will also be interaction between the different phases to take into account.Several measurement techniques have been used and their interrelationships as well as information on their relevance for solar cells have been investigated. Field effect transistors (FET) with an organic active layer have proved to be one of the more versatile measurement geometries and are also an interesting topic in itself. FETs are discussed both as a route for material characterization and as components. A main result correlates bias stress in organic field effect transistors with the electronic structure of the material.Power conversion efficiency in solar cells is discussed with respect to electrical properties. The interaction of different blend materials and the impact of stoichiometry on transport properties in the active layer have been investigated. Results indicate that charge transport properties frequently are a key determining factor for which material combinations and ratios that works best.Some work on the conductive properties of nano-fibers coated with semiconducting polymers has also been done and is briefly discussed. The conductive properties of nano-fibers have been studied through potential imaging.
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| 37. |
- Andersson, Lars M, et al.
(författare)
-
Historikerna och moralen
- 2007
-
Ingår i: Sverige och Nazityskland. - Stockholm : Dialogos. - 9789175042008 ; , s. 9-25
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Bokkapitel (populärvet., debatt m.m.)
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| 38. |
- Andersson, Lars M, et al.
(författare)
-
Lära av det förflutna?
- 2008
-
Ingår i: Fjorton perspektiv på framtiden. - Stockholm : Institutet för Framtidsstudier. - 9789185619344 ; , s. 78-93
-
Bokkapitel (övrigt vetenskapligt/konstnärligt)
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| 39. |
- Andersson, Lars Mattias, et al.
(författare)
-
Non-equilibrium effects on electronic transport in organic field effect transistors
- 2007
-
Ingår i: Organic electronics. - : Elsevier BV. - 1566-1199 .- 1878-5530. ; 8:4, s. 423-430
-
Tidskriftsartikel (refereegranskat)abstract
- Non-ideal behavior in organic field effect transistors, in particular threshold voltage drift and light sensitivity, is argued to be due to intrinsic carrier dynamics. The discussion is based on the theory for hopping transport within a Gaussian density of states. Carrier concentration is shown to be of fundamental importance, and the time required to reach equilibrium at different bias is responsible for device behavior, with implications for mobility evaluation. Experimental results from various conjugated polymers in a field effect transistor illustrate the theory.
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| 40. |
- Andersson, Lars Mattias, et al.
(författare)
-
Stoichiometry, mobility, and performance in bulk heterojunction solar cells
- 2007
-
Ingår i: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 91:7, s. 071108-
-
Tidskriftsartikel (refereegranskat)abstract
- Bipolar transport in blends of a copolymer of fluorene, thiophene and electron accepting groups, and the substituted fullerene [6,6]-phenyl-C61-butyric acid methylester have been studied through charge extraction by linearly increasing voltage on solar cells and with field effect transistors. Between 10% and 90% polymer has been used and the results show a clear correlation to solar cell performance. Optimal solar cells comprise 20% polymer and have a power conversion efficiency of 3.5%. The electron mobility is increasing strongly with fullerene content, but is always lower than the hole mobility, thus explaining the low amount of polymer in optimized devices.
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| 41. |
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| 42. |
- Andersson, Mattias, et al.
(författare)
-
Approximate distance oracles for graphs with dense clusters
- 2007
-
Ingår i: Computational Geometry. - : Elsevier BV. - 0925-7721. ; 37:3, s. 142-154
-
Tidskriftsartikel (refereegranskat)abstract
- Let H1=(V,E1) be a collection of N pairwise vertex disjoint O(1)-spanners where the weight of an edge is equal to the Euclidean distance between its endpoints. Let H2=(V,E2) be the graph on V with M edges of non-negative weight. The union of the two graphs is denoted G=(V,E1 u E2). We present a data structure of size O(M^2 + nlogn) that answers (1+ε)-approximate shortest path queries in G in constant time, where ε>0 is constant.
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| 43. |
- Andersson, Mattias
(författare)
-
Approximation Algorithms for Geometric Networks
- 2007
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The main contribution of this thesis is approximation algorithms for several computational geometry problems. The underlying structure for most of the problems studied is a geometric network. A geometric network is, in its abstract form, a set of vertices, pairwise connected with an edge, such that the weight of this connecting edge is the Euclidean distance between the pair of points connected. Such a network may be used to represent a multitude of real-life structures, such as, for example, a set of cities connected with roads. Considering the case that a specific network is given, we study three separate problems. In the first problem we consider the case of interconnected `islands' of well-connected networks, in which shortest paths are computed. In the second problem the input network is a triangulation. We efficiently simplify this triangulation using edge contractions. Finally, we consider individual movement trajectories representing, for example, wild animals where we compute leadership individuals. Next, we consider the case that only a set of vertices is given, and the aim is to actually construct a network. We consider two such problems. In the first one we compute a partition of the vertices into several subsets where, considering the minimum spanning tree (MST) for each subset, we aim to minimize the largest MST. The other problem is to construct a $t$-spanner of low weight fast and simple. We do this by first extending the so-called gap theorem. In addition to the above geometric network problems we also study a problem where we aim to place a set of different sized rectangles, such that the area of their corresponding bounding box is minimized, and such that a grid may be placed over the rectangles. The grid should not intersect any rectangle, and each cell of the grid should contain at most one rectangle. All studied problems are such that they do not easily allow computation of optimal solutions in a feasible time. Instead we consider approximation algorithms, where near-optimal solutions are produced in polynomial time. In addition to the above geometric network problems we also study a problem where we aim to place a set of different sized rectangles, such that the area of their corresponding bounding box is minimized, and such that a grid may be placed over the rectangles. The grid should not intersect any rectangle, and each cell of the grid should contain at most one rectangle. All studied problems are such that they do not easily allow computation of optimal solutions in a feasible time. Instead we consider approximation algorithms, where near-optimal solutions are produced in polynomial time.
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| 44. |
- Andersson, Mattias, et al.
(författare)
-
Chips on wafers, or packing rectangles into grids
- 2005
-
Ingår i: Computational Geometry. - : Elsevier BV. - 0925-7721. ; 30:2, s. 95-111
-
Tidskriftsartikel (refereegranskat)abstract
- A set of rectangles S is said to be gridpacked if there exists a rectangular grid (not necessarily regular) such that every rectangle lies in the grid and there is at most one rectangle of S in each cell. The area of a grid packing is the area of a minimal bounding box that contains all the rectangles in the grid packing. We present an approximation algorithm that given a set S of rectangles and a real epsilon constant epsilon > 0 produces a grid packing of S whose area is at most (1 + epsilon) times larger than an optimal grid packing in polynomial time. If epsilon is chosen large enough the running time of the algorithm will be linear. We also study several interesting variants, for example the smallest area grid packing containing at least k less than or equal to n rectangles, and given a region A grid pack as many rectangles as possible within A Apart from the approximation algorithms we present several hardness results.
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| 45. |
- Andersson, Mattias, et al.
(författare)
-
Color measurements on prints containing fluorescent whitening agents
- 2007
-
Ingår i: Proceedings of SPIE - The International Society for Optical Engineering. - : SPIE - International Society for Optical Engineering. - 9780819466068 ; , s. Q4930-Q4950
-
Konferensbidrag (refereegranskat)abstract
- Papers with a slightly blue shade are, at least among a majority of observers, perceived as whiter than papers having a more neutral color. Therefore, practically all commercially available printing papers contain bluish dyes and fluorescent whitening agents (FWA) to give the paper a whiter appearance. Furthermore, in the Paper Industry, the most frequently used measure for paper whiteness is the CIE-whiteness. The CIE Whiteness formula, does in turn, also favor slightly bluish papers. Excessive examples of high CIE-whiteness values can be observed in the office-paper segment where a high CIE-whiteness value is an important sales argument. As an effect of the FWA, spectrophotometer measurements of optical properties such as paper whiteness are sensitive to the ultraviolet (UV) content of the light source used in the instrument. To address this, the standard spectrophotometers used in the Paper Industry are equipped with an adjustable filter for calibrating the UV-content of the illumination. In the Paper Industry, spectrophotometers with d/0 measurement geometry and a light source of type C are used. The Graphic Arts Industry on the other hand, typically measures with spectrophotometers having 45/0 geometry and a light source of type A. Moreover, these instruments have only limited possibilities to adjust the UV-content by the use of different weighting filters. The standard for color measurements in the Paper Industry governs that measurements should be carried out using D65 standard illumination and the 10 degrees standard observer. The corresponding standard for the Graphic Arts Industry specify D50 standard illumination and the 2 degrees standard observer. In both cases, the standard illuminants are simulated from the original light source by spectral weighting functions. However, the activation of FWA, which will impact the measured spectral reflectance, depends on the actual UV-content of the illumination used. Therefore, comparisons between measurements on substrates containing FWA from two instruments having light sources with different UV-content are complicated. In this study, the effect of FWA content in paper on color reproduction has been quantified for an office-type paper. Furthermore, examples are given on how color measurement instruments give different readings when FWA is present. For the purpose of this study and in order to ensure that only the effect of FWA was observed, a set of papers with varying additions of FWA but otherwise identical, were produced on a small-scale experimental paper machine. The pilot papers were printed in three different printers. Two spectrophotometers representative to the instruments used in the Graphic Arts Industry and the Paper Industry respectively where used to measure the printed papers. The results demonstrate how the use of spectral weighting functions for simulating standard illuminants works properly on non-fluorescent material. However, when FWA is present, disparities in UV content between the light source and the simulated illuminant will result in color differences. Finally, in many printing processes, some of the used inks are UV-blocking, which further complicates the effect of FWA in printed material. An example is shown on how different color differences are obtained for different process ink combinations when the amount of FWA added to the paper is varied.
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| 46. |
- Andersson, Mattias, 1973-
(författare)
-
Colour Calibration of Trichromatic Capturing Devices
- 2006
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- In a time where there is an increasing demand for easily accessible and up-to-date information, digital printing has become a link between traditional printed media and electronic media. Over the last years, applications such as variable data printing, personalised printing and print on demand have changed the way in which printed matter is produced and handled. The print quality of products produced by digital printing systems has improved considerably in recent years. The main reason for this improvement is better printer hardware but the printing paper is still a very influential factor. The two major technologies, inkjet and electrophotography and their respective applications put very different demands on the paper, mechanically, chemically and optically. Nevertheless, the differences in print quality across digital printing systems are decreasing, except for one area − colour reproduction. The growth of the market of consumer colour imaging products, such as digital printers and desktop printers, has been enormous during the last years. As a consequence of this, consumer expectations on colour reproduction have risen significantly, as even very small failures in colour reproduction can drastically reduce the visual impression of an otherwise impeccably reproduced image. Therefore, as consumer expectations continue to rise, a high and repeatable quality of colour image reproduction is a growing challenge for producers of digital printing devices as well as for paper producers. However, this is impossible to achieve without precise methods and routines to measure colour reproduction quality. The use of spectrophotometers for colour measurements of printed substrates is widely spread among paper producers as well as within the printing industry. Spectrophotometers are precise instruments for point-wise measurements. However, the measurement procedure is very time-consuming and therefore, faster methods for colour measurements are longed-for. If the spectrophotometers used today could be replaced with trichromatic capturing devices such as flatbed scanners or digital cameras, colour characterisation would be not only faster, but also less expensive. In addition, if the trichromatic devices are colorimetrically calibrated, spatial image information can be combined with colour information, making it possible to measure quality attributes related to colour image rendering that are impossible to capture with point-wise measurements. Today, flatbed scanners and digital cameras provide robust and high-quality image capturing capabilities at a relatively low cost. Furthermore, scanner and camera-based systems for automated objective measurements of print quality parameters have already become widely used tools for print quality measurements of print-related properties such as print mottle, sharpness and bleeding. However, the colour calibration of trichromatic capturing devices is not free from obstacles. In colour calibrations, where the aim is to measure colour of printed matter, knowledge about the properties of the capturing device, the printing substrate, the printing process and the printer function are all of great importance. In the work presented here, methods for colour characterisation of printing processes are proposed as well as methods for colour characterisation and calibration of trichromatic capturing devices. Furthermore, the media dependency problem inherent to colour calibrations of trichromatic capturing devices is discussed. Examples are given on how properties of the printed substrate, such as the content of fluorescent whitening agents, influence colour calibrations as well as colour measurements in general.
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| 47. |
- Andersson, Mattias
(författare)
-
Digital camera calibration for color measurements on prints
- 2007
-
Ingår i: Proceedings of SPIE - The International Society for Optical Engineering. - : SPIE - International Society for Optical Engineering. - 9780819466068
-
Konferensbidrag (refereegranskat)abstract
- Papers with a slightly blue shade are, at least among a majority of observers, perceived as whiter than papers having a more neutral color. Therefore, practically all commercially available printing papers contain bluish dyes and fluorescent whitening agents (FWA) to give the paper a whiter appearance. Furthermore, in the Paper Industry, the most frequently used measure for paper whiteness is the CIE-whiteness. The CIE Whiteness formula, does in turn, also favor slightly bluish papers. Excessive examples of high CIE-whiteness values can be observed in the office-paper segment where a high CIE-whiteness value is an important sales argument. As an effect of the FWA, spectrophotometer measurements of optical properties such as paper whiteness are sensitive to the ultraviolet (UV) content of the light source used in the instrument. To address this, the standard spectrophotometers used in the Paper Industry are equipped with an adjustable filter for calibrating the UV-content of the illumination. In the Paper Industry, spectrophotometers with d/0 measurement geometry and a light source of type C are used. The Graphic Arts Industry on the other hand, typically measures with spectrophotometers having 45/0 geometry and a light source of type A. Moreover, these instruments have only limited possibilities to adjust the UV-content by the use of different weighting filters. The standard for color measurements in the Paper Industry governs that measurements should be carried out using D65 standard illumination and the 10 degrees standard observer. The corresponding standard for the Graphic Arts Industry specify D50 standard illumination and the 2 degrees standard observer. In both cases, the standard illuminants are simulated from the original light source by spectral weighting functions. However, the activation of FWA, which will impact the measured spectral reflectance, depends on the actual UV-content of the illumination used. Therefore, comparisons between measurements on substrates containing FWA from two instruments having light sources with different UV-content are complicated. In this study, the effect of FWA content in paper on color reproduction has been quantified for an office-type paper. Furthermore, examples are given on how color measurement instruments give different readings when FWA is present. For the purpose of this study and in order to ensure that only the effect of FWA was observed, a set of papers with varying additions of FWA but otherwise identical, were produced on a small-scale experimental paper machine. The pilot papers were printed in three different printers. Two spectrophotometers representative to the instruments used in the Graphic Arts Industry and the Paper Industry respectively where used to measure the printed papers. The results demonstrate how the use of spectral weighting functions for simulating standard illuminants works properly on non-fluorescent material. However, when FWA is present, disparities in UV content between the light source and the simulated illuminant will result in color differences. Finally, in many printing processes, some of the used inks are UV-blocking, which further complicates the effect of FWA in printed material. An example is shown on how different color differences are obtained for different process ink combinations when the amount of FWA added to the paper is varied.
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| 48. |
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| 49. |
|
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| 50. |
- Andersson, Marcus, 1975, et al.
(författare)
-
Effect of molecular mobility of polymeric implants on soft tissue reactions: An in vivo study in rats
- 2008
-
Ingår i: Journal of Biomedical Materials Research Part A. - : Wiley. - 1552-4965 .- 1549-3296. ; 84A:3, s. 652-660
-
Tidskriftsartikel (refereegranskat)abstract
- Although numerous different polymers are used as implants or otherwise studied for many other biotechnical applications, there is a lack of basic models that correlate polymer characteristics with foreign body reactions. This study aims at developing one such model by systematically studying surface molecular mobility of polymeric implants in soft tissues in vivo. Changing the length of the alkyl side chain of poly(alkyl methacrylates) (PAMAs), provides an interesting opportunity to study the surface molecular mobility with minimal changes of the hydrophobicity of the surface. Thus, in this study three different PAMAs, with increasingly surface mobility; poly (isobutyl methacrylate) (PIBMA), poly(butyl methacrylate) (PBMA), and poly(lauryl methacralate) (PLMA) along with pure titanium (Ti) substrates were implanted in the dorsum of Sprague-Dawley rats. Inflammatory cell recruitment, cell adhesion, and cytokine release were studied after 1, 3, and 28 days of implantation. Total number of inflammatory cells in the exudate was measured but no correlation between surface mobility and cell recruitment where found. However, the number of surface associated cells where significantly lower on the surfaces with high molecular mobility (PLMA and PBMA). The histological evaluation performed after 28 days revealed thicker fibrous capsule and a higher number of blood vessels on the low molecular mobility surface (PIBMA). After 28 days the cell activity was higher on the high molecular mobility surfaces (PLMA and PBMA) compared with PIBMA, based on the cytokine release. None of the surfaces induced any significant cell-death. On the basis of the results of this study we conclude that there is a significant difference in biological response to surfaces with different in molecular mobility. This might affect the wound healing process and the biocompatibility of biomaterials. © 2007 Wiley Periodicals, Inc. J Biomed Mater Res, 2007 -------------------------------------------------------------------------------- Received: 13 March 2006; Revised: 15 December 2006; Accepted: 29 January 2007 Digital Object Identifier (DOI) 10.1002/jbm.a.31389 About DOI
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