| 1. |
- Bräutigam, Marcus, 1968, et al.
(author)
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Development of Swedish winter oat with gene technology and molecular breeding
- 2006
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In: J. Seed Science. - 0039-6990. ; 116:1-2, s. 12-35
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Journal article (peer-reviewed)abstract
- In Sweden, oat (Avena sativa) is only grown as a spring crop. A Swedish winter oat, on the other hand, would give increased yields and would secure oat in Swedish agriculture. During three consecutive winters we performed field trials with oat aiming at identifying potential winter material. More than 300 varieties, originating from breeding programs all over the world, were tested. Plants were rated according to winter survival, vigour and general performance during the following growth season and more than 20 lines were identified that were cold hardier than present commercial oat varieties. In parallel experiments a cDNA library was constructed from cold induced English winter oat (Gerald) and ca 10000 EST sequences were generated. After data mining a UniGene set of 2800 oat genes was obtained. By detailed analysis of microarray data from cold stressed Arabidopsis and by advanced bioinformatics, gene interactions in the complex cold induced signal transduction pathway were deduced. By comparison to the oat UniGene set, several genes potentially involved in the regulation of cold hardiness in oat were identified. An Agrobacterium mediated transformation protocol was developed for one oat genotype. Key regulatory genes in cold acclimation will be introduced to oat by genetic transformation or modified by TILLING. Such genes will be used as molecular markers in intogression of winter hardiness to commercial oat.
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| 2. |
- Hägg, Daniel, 1974, et al.
(author)
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Expression profiling of macrophages from subjects with atherosclerosis to identify novel susceptibility genes.
- 2008
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In: International journal of molecular medicine. - 1107-3756 .- 1791-244X. ; 21:6, s. 697-704
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Journal article (peer-reviewed)abstract
- Although a number of environmental risk factors for atherosclerosis have been identified, heredity seems to be a significant independent risk factor. The aim of our study was to identify novel susceptibility genes for atherosclerosis. The screening process consisted of three steps. First, expression profiles of macrophages from subjects with atherosclerosis were compared to macrophages from control subjects. Secondly, the subjects were genotyped for promoter region polymorphisms in genes with altered gene expression. Thirdly, a population of subjects with coronary heart disease and control subjects were genotyped to test for an association with identified polymorphisms that affected gene expression. Twenty-seven genes were differentially expressed in both macrophages and foam cells from subjects with atherosclerosis. Three of these genes, IRS2, CD86 and SLC11A1 were selected for further analysis. Foam cells from subjects homozygous for the C allele at the -765C-->T SNP located in the promoter region of IRS2 had increased gene expression compared to foam cells from subjects with the nonCC genotype. Also, macrophages and foam cells from subjects homozygous for allele 2 at a repeat element in the promoter region of SLC11A1 had increased gene expression compared to macrophages and foam cells from subjects with the non22 genotype. Genotyping of 512 pairs of subjects with coronary heart disease (CHD) and matched controls revealed that subjects homozygous for C of the IRS2 SNP had an increased risk for CHD; odds ratio 1.43, p=0.010. Immunohistochemical staining of human carotid plaques showed that IRS2 expression was localised to macrophages and endothelial cells in vivo. Our method provides a reliable approach for identifying susceptibility genes for atherosclerosis, and we conclude that elevated IRS2 gene expression in macrophages may be associated with an increased risk of CHD.
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| 3. |
- Auvray, Xavier, 1986, et al.
(author)
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Aging of Cu/SSZ-13 for NH3 SCR in mixed lean condition
- 2018
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Conference paper (other academic/artistic)abstract
- Two catalytic methods have been developed to remove the NOx emissions from diesel vehicles and comply with the emission regulations: the NOx storage and reduction process (NSR) and the reduction of NOx with NH3 (SCR). Advanced systems combining these two methods for an optimum efficiency are now studied. SCR catalysts are subjected alternating lean and rich conditions as well as to high temperatures in rich conditions during deSOx of the LNT material. The purpose of the present work is therefore to determine the response of a Cu/SSZ-13 to several aging treatments at 800°C involving rich and/or lean exposure. Deactivation was observed after all types of aging. However strong differences in deactivation degree exists between aging procedures. Lean aging, for 8h at 800°C, was the most moderate aging tested although it brought about significant activity loss below 250°C. Alternating between long lean periods and short rich periods caused slightly stronger deactivation, which was most significant at 200°C. However, the switching frequency between lean and rich had negligible influence on subsequent activity. As shown in Figure 1, SCR activity after 8h exposure in H2 was outstandingly low. It increased monotonically with temperature to reach a maximum of 58% NO conversion. Further investigation pertaining to the rich treatment was performed. The aging time was reduced to 2h and, for direct comparison, a 32h cycling aging was performed, implying a total rich time of 2h. Both samples were severely impacted over the whole temperature range. It revealed that 2h in rich conditions led to stronger deactivation than 8h in lean and lean/rich conditions, emphasizing the deterioration power of H2. Aging caused by rich conditions was so dominant that additional 30h in lean has negligible influence on SCR below 300°C. However, the long additional exposure to lean conditions lowered significantly the SCR activity between 400 and 500°C.
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| 4. |
- Auvray, Xavier, 1986, et al.
(author)
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Deactivation of Cu/SSZ-13 NH3-SCR catalyst by exposure to CO, H2, and C3H6
- 2019
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In: Catalysts. - : MDPI AG. - 2073-4344. ; 9:11
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Journal article (peer-reviewed)abstract
- Lean nitric oxide (NOx)-trap (LNT) and selective catalytic reduction (SCR) are efficient systems for the abatement of NOx. The combination of LNT and SCR catalysts improves overall NOx removal, but there is a risk that the SCR catalyst will be exposed to high temperatures and rich exhaust during the LNTs sulfur regeneration. Therefore, the effect of exposure to various rich conditions and temperatures on the subsequent SCR activity of a Cu-exchanged chabazite catalyst was studied. CO, H2, C3H6, and the combination of CO + H2 were used to simulate rich conditions. Aging was performed at 800 °C, 700 °C, and, in the case of CO, 600 °C, in a plug-flow reactor. Investigation of the nature of Cu sites was performed with NH3-temperature-programed desorption (TPD) and diffuse reflectance infrared Fourier transform spectroscopy (DRIFT) of probe molecules (NH3 and NO). The combination of CO and H2 was especially detrimental to SCR activity and to NH3 oxidation. Rich aging with low reductant concentrations resulted in a significantly larger deactivation compared to lean conditions. Aging in CO at 800 °C caused SCR deactivation but promoted high-temperature NH3 oxidation. Rich conditions greatly enhanced the loss of Brønsted and Lewis acid sites at 800 °C, indicating dealumination and Cu migration. However, at 700 °C, mainly Brønsted sites disappeared during aging. DRIFT spectroscopy analysis revealed that CO aging modified the Cu2+/CuOH+ ratio in favor of the monovalent CuOH+ species, as opposed to lean aging. To summarize, we propose that the reason for the increased deactivation observed for mild rich conditions is the transformation of the Cu species from Z2Cu to ZCuOH, possibly in combination with the formation of Cu clusters. © 2019, MDPI AG. All rights reserved.
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| 5. |
- Auvray, Xavier, 1986, et al.
(author)
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Lean and rich aging of a Cu/SSZ-13 catalyst for combined lean NO x trap (LNT) and selective catalytic reduction (SCR) concept
- 2019
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In: Catalysis Science and Technology. - : Royal Society of Chemistry (RSC). - 2044-4753 .- 2044-4761. ; 9:9, s. 2152-2162
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Journal article (peer-reviewed)abstract
- © 2019 The Royal Society of Chemistry. In the combined lean NO x trap (LNT) and selective catalytic reduction (SCR) concept, the SCR catalyst can be exposed to rich conditions during deSO x of the LNT. Aging of Cu/SSZ-13 SCR catalysts, deposited on a cordierite monolith, was therefore studied in rich, lean and cycling lean/rich operations at 800 °C (lean condition: 500 ppm NO, 8% O 2 , 10% H 2 O and 10% CO 2 ; rich condition: 500 ppm NO, 1% H 2 , 10% H 2 O and 10% CO 2 ). The structure of the catalyst was investigated by X-ray diffraction (XRD), surface area measurements and scanning transmission electron microscopy (STEM). In general, aging decreased the SCR activity and NH 3 oxidation. However, rich conditions showed a very rapid and intense deactivation, while lean aging led to only a small low-temperature activity decrease. The XRD results showed no sign of structure collapse, but the number of active sites, as titrated by NH 3 temperature-programed desorption (NH 3 -TPD) and in situ DRIFTS, revealed an important loss of acid sites. NH 3 storage was significantly more depleted after rich aging than after lean aging. The Lewis sites, corresponding to exchange Cu 2+ , were preserved to some extent in lean conditions. Lean aging also decreased the enthalpy of NH 3 adsorption from -158 kJ mol -1 to -136 kJ mol -1 . Moreover, a comparison of aging in lean-rich cycling conditions with aging only in rich conditions revealed that adding lean events did not hinder or reverse the deactivation, and it was mainly the time in rich conditions that determined the extent of the deactivation. The STEM images coupled with elemental analysis revealed the formation of large Cu particles during rich aging. Conversely, Cu remained well dispersed after lean aging. These results suggest that the copper migration and agglomeration in large extra-framework particles, accelerated by the action of hydrogen, caused the observed severe deactivation.
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| 6. |
- Bergstrom, S., et al.
(author)
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J-factors for self-interacting dark matter in 20 dwarf spheroidal galaxies
- 2018
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In: Physical Review D. - 2470-0010 .- 2470-0029. ; 98:4
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Journal article (peer-reviewed)abstract
- Dwarf spheroidal galaxies are among the most promising targets for indirect dark matter (DM) searches in gamma rays. The gamma-ray flux from DM annihilation in a dwarf spheroidal galaxy is proportional to the J-factor of the source. The J-factor of a dwarf spheroidal galaxy is the line-of-sight integral of the DM mass density squared times /(0), where sigma(ann)v(rel) is the DM annihilation cross-section times relative velocity v(rel) = vertical bar v(rel)vertical bar angle brackets denote average over v(rel), and (sigma(ann)v(rel)) is the v(rel)-independent part of sigma(ann)v(rel). If sigma(ann)v(rel) is constant in v(rel), J-factors only depend on the DM space distribution in the source. However, if sigma(ann)v(rel) varies with v(rel), as in the presence of DM self-interactions, J-factors also depend on the DM velocity distribution, and on the strength and range of the DM self-interaction. Models for self interacting DM are increasingly important in the study of the small scale clustering of DM, and are compatible with current astronomical and cosmological observations. Here we derive the J-factor of 20 dwarf spheroidal galaxies from stellar kinematic data under the assumption of Yukawa DM self-interactions. J-factors are derived through a profile likelihood approach, assuming either NavarroFrenk-White (NEW) or cored DM profiles. We also compare our results with J-factors derived assuming the same velocity for all DM particles in the target galaxy. We find that this common approximation overestimates the Mactors by up to 1 order of magnitude. J-factors for a sample of DM particle masses and self-interaction coupling constants, as well as for NFW and cored density profiles, are provided electronically, ready to he used in other projects.
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| 7. |
- Berntsson, Thore, 1947, et al.
(author)
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Vad är ett bioraffinaderi?
- 2014
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In: Perspektiv på förädling av bioråvara 2014. - 9789198097450 ; , s. 8-9
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Book chapter (other academic/artistic)
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| 8. |
- Berntsson, Thore, 1947, et al.
(author)
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What is a biorefinery?
- 2012
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In: Systems Perspectives on Biorefineries 2012. - 9789198030013 ; , s. 16-25
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Book chapter (other academic/artistic)abstract
- The term “biorefinery” appeared in the 1990’s in response to a least four industry trends. First, there was an increased awareness in industry of the need to use biomass resources in a more rational way both economically and environmentally. The environmental issue was both policy and consumer driven. Second, therewas a growing interest in upgrading more low-quality lignocellulosic biomass to valuable products. Third, there was an increased attention to the production of starch for energy applications. Finally, there was a perceived need to develop more high-value products and diversify the product mix in order to meet global competi- tion and, in some cases, utilise an excess of biomass (especially in the pulp and paper industry).In a biorefinery, biomass is upgraded to one or more valuable products such as transport fuels, materials, chemicals, electricity and, as byproduct, heat. In principle all types of biomass can be used, e.g. wood, straw, starch, sugars, waste and algae. But there is more to it than that. The aim of this chapter is to explain in some more detail what a biorefinery is or could be.There have been many attempts to determine what should be meant by a “biorefinery” and in the next section we provide some of the definitions and additional meaning that has been attached to the concept. To give a more in-depth understanding of what a biorefinery might be, the following sections describe process technologies that are often considered as key constituent parts of biorefineries and some opportunities for integration in existing processing industry that also can be viewed as biorefining.
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| 9. |
- Bärring, Maja, 1988, et al.
(author)
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A VSM Approach to Support Data Collection for a Simulation Model
- 2017
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In: Proceedings - Winter Simulation Conference. - 0891-7736. ; , s. 3928-3939
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Conference paper (peer-reviewed)abstract
- Simulation is a powerful tool to analyze and help in the decision making process of a production system. It is capable of delivering a dynamic analysis, both of the existing system and the future planned system. One major challenge with simulation projects however, is the time required at the initial stage when collecting data. For this study, Value Stream Mapping (VSM) has been selected as a complementary method for the data collection. VSM has been widely spread in industry, and it is a suitable method for identifying value streams and visualizing flows. In this study, the applicability of VSM for data collection is examined for a production system with complex and non-linear flows. The results of this study confirms that VSM can support in the data collection phase, but entails the support from subject matters.
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| 10. |
- Carlsson, Nils, 1978, et al.
(author)
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Enzymes Immobilized in Mesoporous Silica: a Physical-Chemical Perspective
- 2014
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In: Advances in Colloid and Interface Science. - : Elsevier BV. - 0001-8686. ; 205, s. 339-360
-
Research review (peer-reviewed)abstract
- Mesoporous materials as support for immobilized enzymes have been explored extensively during the last two decades, primarily not only for biocatalysis applications, but also for biosensing, biofuels and enzyme-controlled drug delivery. The activity of the immobilized enzymes inside the pores is often different compared to that of the free enzymes, and an important challenge is to understand how the immobilization affects the enzymes in order to design immobilization conditions that lead to optimal enzyme activity. This review summarizes methods that can be used to understand how material properties can be linked to changes in enzyme activity. Real-time monitoring of the immobilization process and techniques that demonstrate that the enzymes are located inside the pores is discussed by contrasting them to the common practice of indirectly measuring the depletion of the protein concentration or enzyme activity in the surrounding bulk phase. We propose that pore filling (pore volume fraction occupied by proteins) is the best standard for comparing the amount of immobilized enzymes at themolecular level, and present equations to calculate pore filling from the more commonly reported immobilized mass. Methods to detect changes in enzyme structure upon immobilization and to study the microenvironment inside the pores are discussed in detail. Combining the knowledge generated from these methodologies should aid in rationally designing biocatalyst based on enzymes immobilized in mesoporous materials.
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