| 1. |
- Hansen, Nils, et al.
(author)
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SOCS2 is dispensable for BCR/ABL1-induced chronic myeloid leukemia-like disease and for normal hematopoietic stem cell function.
- 2013
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In: Leukemia. - : Springer Science and Business Media LLC. - 1476-5551 .- 0887-6924. ; 27, s. 130-135
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Journal article (peer-reviewed)abstract
- Suppressor of cytokine signaling 2 (SOCS2) is known as a feedback inhibitor of cytokine signaling and is highly expressed in primary bone marrow (BM) cells from patients with chronic myeloid leukemia (CML). However, it has not been established whether SOCS2 is involved in CML, caused by the BCR/ABL1 fusion gene, or important for normal hematopoietic stem cell (HSC) function. In this study, we demonstrate that although Socs2 was found to be preferentially expressed in long-term HSCs, Socs2-deficient HSCs were indistinguishable from wild-type HSCs when challenged in competitive BM transplantation experiments. Furthermore, by using a retroviral BCR/ABL1-induced mouse model of CML, we demonstrate that SOCS2 is dispensable for the induction and propagation of the disease, suggesting that the SOCS2-mediated feedback regulation of the JAK/STAT pathway is deficient in BCR/ABL1-induced CML.Leukemia advance online publication, 24 July 2012; doi:10.1038/leu.2012.169.
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| 2. |
- Lee, S. W., et al.
(author)
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Sol-gel integrated protein microarray for high-resolution signal readout of psa (prostate specific antigen) in clinical samples
- 2010
-
In: 14th International Conference on Miniaturized Systems for Chemistry and Life Sciences 2010, MicroTAS 2010. - 9781618390622 ; 2, s. 800-802
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Conference paper (peer-reviewed)abstract
- In this study, we demonstrate a new protein microarray technology for highly sensitive detection of PSA (prostate caser specific antigen) in scrum samples. Using the optically active sol-gel nanocomposites, which can hold capturing probes in native and surface morphology tailored porous silicon, purified PSA (Prostate Specific Antigen) in human female serum was assessed by FlTC-antiPSA in broad dynamic range of the sandwich (1 pg/mL to Ing/mL). Additionally, we tested reverse phase assay using our developed system, which purified PSA imbedded in sol-gel and FITC labeled its counter antibody was accessed. Dynamic range was 60 fg/mL to 6ng/mL. Our concept can allow the measurement oflow amount of PSA at pg/ml range and thus, it is possible to do relative quantification for marker protein as well.
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| 3. |
- Lögdberg, Sara, et al.
(author)
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Further insights into methane and higher hydrocarbons formation over cobalt-based catalysts with γ-Al2O3, α-Al2O3 and TiO2 as support materials
- 2017
-
In: Journal of Catalysis. - : Academic Press. - 0021-9517 .- 1090-2694. ; 352, s. 515-531
-
Journal article (peer-reviewed)abstract
- A range of cobalt-based catalysts varying in Co loading and prepared by incipient wetness impregnation of traditional support materials (γ-Al2O3, α-Al2O3 and TiO2), have been studied in the Fischer-Tropsch reaction at industrially relevant process conditions (483 K, 20 bar, H2/CO = 2.1). A high selectivity to C5+ hydrocarbons (SC5+) is to a great extent connected with a high site activity, but not exclusively. We propose that the ratio of monomer-production rate to C–C coupling rate of a catalyst determines chain-growth probability by means of governing the coverage of the monomer on the cobalt surface. We speculate that this ratio depends on e.g. shape, strain and size of the Co crystallites and, therefore, is highly dependent on the choice of support material. No general relationship between Co particle size and SC5+ is found, but individual correlations exist for each support material. Within each support material, there are indications of negative correlations between the chain-growth probability of the C1 ∗ surface intermediate (αC1) and the higher αCn values. This can be rationalized by assuming that the majority of methane is formed by a different mechanism, separate from chain growth, but connected with chain growth through a common carbon pool. We propose that the monomers and the majority of methane are produced at sites different from the ones involved in chain growth. There is no general correlation between αC1 and SC5+ for catalysts with different support materials, possibly due to small differences in cobalt surface coverage of hydrogen. For the TiO2-supported catalysts, a dramatically increased αC1 value observed for catalysts with Co particles smaller than approx. 15 nm, is probably associated with strong metal-support interactions (SMSI). This phenomenon apparently limits the effect (reduction) on the SC5+ when moving toward smaller Co particles.
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| 4. |
- Montes, V., et al.
(author)
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Preparation and characterization of Pt-modified Co-based catalysts through the microemulsion technique : Preliminary results on the Fischer-Tropsch synthesis
- 2014
-
In: Catalysis Today. - : Elsevier BV. - 0920-5861 .- 1873-4308. ; 223, s. 66-75
-
Journal article (peer-reviewed)abstract
- The influence of the addition of small amounts of platinum (0.1-0.25% wt) to cobalt-based systems on Fischer-Tropsch synthesis was investigated. The solids were synthesized through microemulsion technique using TiO2 as the support. The best catalytic performance was achieved using Synperonic 13/6.5 as the surfactant. In all cases, the presence of platinum led to an increase in CO conversion which could be ascribed to the promotion of cobalt reducibility as evidenced by XPS. Moreover, the simultaneous reduction of cobalt and platinum precursors during synthetic procedure (ME1) was preferable to the consecutive one (ME2) probably as a result of a better Co-Pt interaction in the former case, as evidenced by TPR. TPR, Raman and XPS data also suggested that not only the presence of Co-0 but also the appearance of Co-TiO2 interactions favor the catalytic performance and that in general those interactions are stronger for ME1 solids.
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| 5. |
- Montes, V., et al.
(author)
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Selective transformation of glycerol into 1,2-propanediol on several Pt/ZnO solids : Further insight into the role and origin of catalyst acidity
- 2015
-
In: Catalysis Today. - : Elsevier BV. - 0920-5861 .- 1873-4308. ; 257, s. 246-258
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Journal article (peer-reviewed)abstract
- Microemulsion technique allowed us to synthesize different ZnO solids with similar particle sizes and textural properties. Platinum was subsequently incorporated by deposition-precipitation and impregnation methods and solids tested for glycerol selective transformation into 1,2-PDO. Incorporation of platinum led to the creation of new (mainly Lewis) acid sites. A good correlation between conversion and acidity of Pt/ZnO solids was obtained. Interestingly, despite exhibiting some acidity, supports alone were inactive in the process which evidenced the role of the metal in dehydration of glycerol into acetol. Furthermore, as the reaction proceeded some chlorine coming from the precursor (H2PtCl6) was leached which led to the disappearance of the strongest acid sites, associated to side reactions (catalytic cracking) thus resulting in an increase in selectivity to 1,2-PDO. Eventual formation of Pt-Zn alloy upon reduction of the systems at ca. 400 degrees C was beneficial to 1,2-PDO selectivity.
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| 6. |
- Montes, V., et al.
(author)
-
Synthesis of different ZnO-supported metal systems through microemulsion technique and application to catalytic transformation of glycerol to acetol and 1,2-propanediol
- 2014
-
In: Catalysis Today. - : Elsevier BV. - 0920-5861 .- 1873-4308. ; 223, s. 129-137
-
Journal article (peer-reviewed)abstract
- Different systems consisting of diverse metals (Au, Pt, Pd, Rh) supported on ZnO (5% by weight) were synthesized through the microemulsion technique (ME) and tested for glycerol hydrogenolysis, the main products being hydroxyacetone (acetol) and 1,2-propanediol (1,2-PDO). The solids synthesized using sodium borohydride as the reducing agent (B series) had smaller particle sizes as compared to the use of hydrazine (H series) which, in turn, resulted in a better catalytic performance. This synthetic method allowed us to obtain similar metal particle sizes (2-4 nm) for Pt, Pd and Rh solids in B series, whereas average gold metal particle was higher (> 8 nm) which probably accounts for Au-containing systems being inactive under our experimental conditions. Reactivity order followed the sequence Rh > Pt > Pd. A comparison of the systems synthesized in the present paper through ME technique with those obtained in a previous work through the deposition-precipitation process revealed a higher activity and selectivity to acetol for the former solids which could be related to the presence of surfactant. Moreover, results suggested that metal sites could participate not only in hydrogenation of acetol to 1,2-propanediol but also in the previous dehydration step of glycerol to acetol.
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| 7. |
- Persson, K., et al.
(author)
-
Preparation of alumina-supported palladium catalysts for complete oxidation of methane
- 2003
-
In: Applied Catalysis A. - : Elsevier BV. - 0926-860X .- 1873-3875. ; 249:1, s. 165-174
-
Journal article (peer-reviewed)abstract
- Alumina-supported palladium catalysts (Pd/Al2O3) have been prepared by incipient wetness (IW), grafting (G) and microemulsion techniques (ME). Two slightly different microemulsion methods have been used (ME1) and (ME2). The catalysts have been calcined at 1000 degreesC for 4 h. The catalysts have then been examined with respect to their activity for the combustion of methane, during heating and cooling ramps. Pd/Al2O3-IW and Pd/Al2O3-ME2 exhibit the highest activity whereas Pd/Al2O3-ME1 and Pd/Al2O3-G are the less active. There is not much of a difference in activity between Pd/Al2O3-IW and Pd/Al2O3-ME2, despite strong differences in palladium particle size observed by TEM analysis. TPO experiments show that Pd/Al2O3-IW and Pd/Al2O3-ME2 present a higher PdO/Pd ratio than the other samples exhibit. The preparation technique affects the reoxidation ability of palladium during cooling, hence the combustion activity of the fresh catalyst, as PdO is more active than Pd for the complete oxidation of methane under lean conditions.
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| 8. |
- Rojas, S., et al.
(author)
-
Preparation of carbon supported Pt and PtRu nanoparticles from microemulsion - Electrocatalysts for fuel cell applications
- 2005
-
In: Applied Catalysis A. - : Elsevier BV. - 0926-860X .- 1873-3875. ; 285:02-jan, s. 24-35
-
Journal article (peer-reviewed)abstract
- A series of platinum and platinum ruthenium carbon supported electrocatalyst have been prepared by the microemulsion technique. The influence of parameters such as the preparation route, the metal loading and the PtRu stoichiometry on the morphology of the final nanoparticles has been studied. Irrespective the total metal loading, nanosized particles, displaying a narrow size distribution were obtained. In addition, particle size was found to be independent of the metal loading. Structural characteristics of these systems have been studied by XPS, X-ray diffraction, TEM, and TPR-TPO and their textural parameters by N-2 adsorption. The catalytic performance of the samples was evaluated in the electrochemical oxidation of methanol. The influence of the morphology on the catalytic performance of the catalysts is discussed in terms of their synthesis route. © 2005 Elsevier B.V. All rights reserved.
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| 9. |
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| 10. |
- Thevenin, P. O., et al.
(author)
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Catalytic combustion of methane over cerium-doped palladium catalysts
- 2003
-
In: Journal of Catalysis. - : Elsevier BV. - 0021-9517 .- 1090-2694. ; 215:1, s. 78-86
-
Journal article (peer-reviewed)abstract
- Various Pd-supported catalysts have been prepared using three different types of alumina as support material: (a) gamma-alumina, (b) Ba-stabilized alumina, and
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| 11. |
- Thevenin, P. O., et al.
(author)
-
Characterization and activity of supported palladium combustion catalysts
- 2002
-
In: Journal of Catalysis. - : Elsevier BV. - 0021-9517 .- 1090-2694. ; 207:1, s. 139-149
-
Journal article (peer-reviewed)abstract
- The catalytic activity of Pd supported on gamma-Al2O3, Ba-Al2O3, and La-Al2O3 has been examined in complete oxidation of methane when operating in excess of oxygen. Two different sizes of I'd particles have been considered. Foreign ions have a strong influence with respect to the stabilization of alumina when submitted to a temperature as high as 1000 degrees C. In contrast, no specific effect can be detected when the samples are calcined at 500 degreesC. Interaction with the supported palladium particles, observed during the combustion reaction, has been investigated by X-ray photoelectron Spectroscopy and temperature-programmed oxidation. The difference in combustion activity is attributed to the difference in surface oxidation states of the Pd particles. The presence of foreign ions in the alumina structure results in surface PdO only. When supported on gamma-Al2O3, small amounts of metallic Pd can be detected, resulting in a lower ignition temperature.
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| 12. |
- Agrell, J., et al.
(author)
-
Production of hydrogen by partial oxidation of methanol over Cu/ZnO catalysts prepared by microemulsion technique
- 2001
-
In: Applied Catalysis A. - 0926-860X .- 1873-3875. ; 211:2, s. 239-250
-
Journal article (peer-reviewed)abstract
- Production of hydrogen by partial oxidation of methanol, using air as oxidant. has been studied over a series of Cu/ZnO catalysts prepared by microemulsion technique. The catalytic activity was compared to that of a reference catalyst prepared by conventional co-precipitation. The BET surface areas of the microemulsion catalysts (30-70 wt.% Cu) ranged from 22 to 36 m(2)/g and were considerably lower than that of the reference (60 m(2)/g). Nevertheless, the microemulsion catalysts were more active in the partial oxidation reaction and exhibited high hydrogen and carbon dioxide selectivities. At a molar O-2/CH3OH ratio of 0.1, hydrogen production was initiated at about 185 degreesC over the microemulsion catalysts. Over the reference, hydrogen production began at 215 degreesC under the same conditions. The catalytic activity was Found to be strongly dependent on the partial pressure of oxygen, which also plays an important role in determining the product distribution. By increasing the O-2/CH3OH ratio, the methanol conversion and carbon dioxide selectivity increase. while production of water occurs at the expense of hydrogen. By TEM and TPR, it was observed that Cu is less well-dispersed in the microemulsion catalysts than in the reference. The higher catalytic activity is not expected considering the lower number of exposed Cu sites, i.e, the turnover frequencies are substantially higher over the microemulsion catalysts. It is possible that, a strong interaction between a small part of CuO and the ZnO lattice is responsible for the higher turnover frequencies of the microemulsion catalysts, or that particular crystallographic Cu planes or surface imperfections are the active sites of the reaction.
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| 13. |
- Agrell, J., et al.
(author)
-
Production of hydrogen by partial oxidation of methanol over ZnO-supported palladium catalysts prepared by microemulsion technique
- 2003
-
In: Applied Catalysis A. - 0926-860X .- 1873-3875. ; 242:2, s. 233-245
-
Journal article (peer-reviewed)abstract
- Selective production of hydrogen by partial oxidation of methanol, using air as oxidant, was studied over a series of ZnO-supported Pd catalysts. Microemulsion-assisted synthesis and conventional impregnation techniques were used for preparation of catalysts containing Pd particles of different sizes. Catalyst characterisation included BET, XRD and TEM analyses. The influence of Pd particle size on catalytic activity and product distribution was studied by carrying out activity measurements at temperatures between 230 and 300 degreesC using a stoichiometric feed composition. All catalysts performed well with respect to methanol conversion and hydrogen yield. Both methanol conversion and hydrogen selectivity increased with increasing reaction temperature, the latter at the expense of water formation. Oxygen conversion was complete throughout the examined temperature range. These selectivity trends, with a strong dependence of hydrogen and carbon monoxide selectivities on methanol conversion and reaction temperature, support a reaction scheme consisting of consecutive methanol combustion, steam reforming and decomposition. More importantly, a correlation between Pd particle size and carbon monoxide selectivity was found. When the microemulsion catalysts are compared, carbon monoxide formation increases with increasing particle size. This was not observed over the impregnated reference catalysts, which exhibited high carbon monoxide-levels throughout the examined temperature range. Bimetallic PdZn particles were detected in spent catalysts by means of XRD and it is suggested that the catalytic activity is dependent on the formation of PdZn, the catalytic function being different from that of Pd-0.
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| 14. |
- Arnardottir, Steinunn, et al.
(author)
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Long-term outcomes of patients with acromegaly: a report from the Swedish Pituitary Register
- 2022
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In: European Journal of Endocrinology. - : European Society of Endocrinology. - 1479-683X .- 0804-4643. ; 186:3, s. 329-339
-
Journal article (peer-reviewed)abstract
- Objective: To describe the treatment and long-term outcomes of patients with acromegaly from all healthcare regions in Sweden. Design and methods: Analysis of prospectively reported data from the Swedish Pituitary Register of 698 patients (51% females) with acromegaly diagnosed from 1991 to 2011. The latest clinical follow-up date was December 2012, while mortality data were collected for 28.5 years until June 2019. Results: The annual incidence was 3.7/million; 71% of patients had a macroadenoma, 18% had visual field defects, and 25% had at least one pituitary hormone deficiency. Eighty-two percent had pituitary surgery, 10% radiotherapy, and 39% medical treatment. At the 5- and 10-year follow-ups, insulin-like growth factor 1 levels were within the reference range in 69 and 78% of patients, respectively. In linear regression, the proportion of patients with biochemical control including adjuvant therapy at 10 years follow-up increased over time by 1.23% per year. The standardized mortality ratio (SMR) (95% CI) for all patients was 1.29 (1.11-1.49). For patients with biochemical control at the latest follow-up, SMR was not increased, neither among patients diagnosed between 1991 and 2000, SMR: 1.06 (0.85-1.33) nor between 2001 and2011, SMR: 0.87 (0.61-1.24). In contrast, non-controlled patients at the latest follow-up from both decades had elevated SMR, 1.90 (1.33-2.72) and 1.98 (1.24-3.14), respectively. Conclusions: The proportion of patients with biochemical control increased over time. Patients with biochemically controlled acromegaly have normal life expectancy, while non-controlled patients still have increased mortality. The high rate of macroadenomas and unchanged age at diagnosis illustrates the need for improvements in the management of patients with acromegaly.
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| 15. |
- Elm Svensson, Erik, 1976-
(author)
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Nanotemplated High-Temperature Materials for Catalytic Combustion
- 2008
-
Doctoral thesis (other academic/artistic)abstract
- Catalytic combustion is a promising technology for heat and power applications, especially gas turbines. By using catalytic combustion ultra low emissions of nitrogen oxides (NOX), carbon monoxide (CO) and unburned hydrocarbons (UHC) can be reached simultaneously, which is very difficult with conventional combustion technologies. Besides achieving low emission levels, catalytic combustion can stabilize the combustion and thereby be used to obtain stable combustion with low heating-value gases. This thesis is focused on the high-temperature part of the catalytic combustor. The level of performance demanded on this part has proven hard to achieve. In order to make the catalytic combustor an alternative to the conventional flame combustor, more stable catalysts with higher activity have to be developed. The objective of this work was to develop catalysts with higher activity and stability, suitable for the high-temperature part of a catalytic combustor fueled by natural gas. Two template-based preparation methods were developed for this purpose. One method was based on soft templates (microemulsion) and the other on hard templates (carbon). Supports known for their stability, magnesia and hexaaluminate, were prepared using the developed methods. Catalytically active materials, perovskite (LaMnO3) and ceria (CeO2), were added to the supports in order to obtain catalysts with high activities and stabilities. The supports were impregnated with active materials by using a conventional technique as well as by using the microemulsion technique. It was shown that the microemulsion method can be used to prepare catalysts with higher activity compared to the conventional methods. Furthermore, by using a microemulsion to apply active materials onto the support a significantly higher activity was obtained than when using the conventional impregnation technique. Since the catalysts will operate in the catalytic combustor for extended periods of time under harsh conditions, an aging study was performed on selected catalysts prepared by the microemulsion technique. The stability of the catalysts was assessed by measuring the activity before and after aging at 1000 C in humid air for 100 h. One of the most stable catalysts reported in the literature, LMHA (manganese-substituted lanthanum hexaaluminate), was included in the study for comparative purposes. The results showed that LMHA deactivated much more strongly compared to several of the catalysts consisting of ceria supported on lanthanum hexaaluminate prepared by the developed microemulsion method. Carbon templating was shown be a very good technique for the preparation of high-surface-area hexaaluminates with excellent sintering resistance. It was found that the pore size distribution of the carbon used as template was a crucial parameter in the preparation of hexaaluminates. When a carbon with small pores was used as template, the formation of the hexaaluminate crystals was strongly inhibited. This resulted in a material with poor sintering resistance. On the other hand, if a carbon with larger pores was used as template, it was possible to prepare materials with hexaaluminate as the major phase. These materials were, after accelerated aging at 1400 C in humid air, shown to retain surface areas twice as high as reported for conventionally prepared materials.
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| 16. |
- Eriksson, Sara, et al.
(author)
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Experimental and numerical investigation of supported rhodium catalysts for partial oxidation of methane in exhaust gas diluted reaction mixtures
- 2007
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In: Chemical Engineering Science. - : Elsevier BV. - 0009-2509 .- 1873-4405. ; 62:15, s. 3991-4011
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Journal article (peer-reviewed)abstract
- The partial oxidation of methane/oxygen mixtures with large exhaust gas dilution (46.3 vol% H2O and 23.1 vol% CO2) has been investigated experimentally and numerically over Rh/CeO2-ZrO2, Rh/ZrO2 and Rh/alpha-Al2O3 catalysts. Experiments were carried out in a short-contact-time (similar to 8 ms) reactor at 5 bar and included exhaust gas analysis, temperature measurements along the reactor, and catalyst characterization. Additional experiments were performed in an optically accessible channel-flow reactor and involved in situ Raman measurements of major gas-phase species concentrations over the catalyst boundary layer and laser-induced fluorescence (LIF) of formaldehyde. A full elliptic two-dimensional numerical code that included elementary hetero-/homogeneous chemical reaction schemes and relevant heat transfer mechanisms in the solid was used in the simulations. The employed heterogeneous reaction mechanism, including only active Rh sites, reproduced the experiments with good accuracy. The ratio of active to geometrical surface area, deduced from hydrogen chemisorption measurements, was the single model parameter needed to account for the effect of different supports. This indicated that water activation occurring on support sites, resulting in inverse OH spillover from the support to the noble metal sites, could be neglected under the present conditions with high water dilution. An evident relationship between noble metal dispersion and catalytic behavior, in terms of methane conversion and synthesis gas yields, could be established. Both measurements and predictions indicated that an increasing Rh dispersion (in the order Rh/alpha-Al2O3, Rh/ZrO2, and Rh/CeO2-ZrO2) resulted in higher methane conversions, lower surface temperatures, and higher synthesis gas yields.
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| 17. |
- Eriksson, Sara, et al.
(author)
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Fuel-rich catalytic combustion of methane in zero emissions power generation processes
- 2006
-
In: Catalysis Today. - : Elsevier BV. - 0920-5861 .- 1873-4308. ; 117:4, s. 447-453
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Journal article (peer-reviewed)abstract
- A novel catalytic combustion concept for zero emissions power generation has been investigated. Catalysts consisting of Rh supported on ZrO2, Ce-ZrO2 or alpha-Al2O3 were prepared and tested under fuel-rich conditions, i.e. for catalytic partial oxidation (CPO) of methane. The experiments were performed in a subscale gas-turbine reactor operating at 5 bar with exhaust gas-diluted feed mixtures.The catalyst support material was found to influence the light-off temperature significantly, which increased in the following order Rh/Ce-ZrO2 < Rh/ZrO2 < Rh/alpha-Al2O3. The Rh loading, however, only had a minor influence. The high activity of Rh/Ce-ZrO2 is probably related to the high dispersion of Rh on Ce-ZrO2 and the high oxygen mobility of this support compared to pure ZrO2. The formation of hydrogen was also found to increase over the catalyst containing ceria in the support material.
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| 18. |
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| 19. |
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| 20. |
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| 21. |
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| 22. |
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| 23. |
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| 24. |
- Johansson, E. M., et al.
(author)
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Development of hexaaluminate catalysts for combustion of gasified biomass in gas turbines
- 2002
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In: Journal of engineering for gas turbines and power. - : ASME International. - 0742-4795 .- 1528-8919. ; 124:2, s. 235-238
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Journal article (peer-reviewed)abstract
- There is an increasing interest in Catalytic combustors fuelled by low-heating value (LHV) gases, with a LHV of 5-7 MJ/Nm(3). This is because catalytic combustion could be advantageous compared to flame combustion with respect to stable combustion of LHV-gases and low conversions of fuel-N (mainly NH3) to NOX. In the present project, funded by the EU Joule Program, catalytic combustion of gasified wood for gas turbine applications is studied. A synthetic gas mixture of H-2, CO, CO2, H2O, CH4, N-2, and NH3, that resembles the output from a fluidized bed gasifier using biomass as raw material, is used. The gas mixture is mixed with air at atmospheric pressure and combusted over wash-coated cordierite monoliths in a bench-scale laboratory quartz-reactor. The objectives of the work described here are twofold. To begin with, improvement of the thermal stability of hexaaluminate washcoats by substitutions of rare earth or transition metal compounds is being studied. Secondly, catalytic combustion of gasified biomass over these washcoats has been studied in a bench-scale unit. In. this on-going project, obtained result show that it is possible to improve the surface area of hexaaluminate compounds up to 17 m(2)/g after careful synthesis and calcination up to 1400degreesC for four hours. The selectivity of NH3-conversion to N-2 is at present at 60 percent, but varies strongly with temperature. Fuel components such as H-2, CO, C2H4, and NH3 ignite at temperatures close to compressor outlet temperatures. This means that a pilot-flame may not be needed for ignition of the fuel. A comparison between a Pd-impregnated lanthanum hexaaluminate and a Mn-substituted lanthanum hexaaluminate showed that the ignition temperature and the NOX-formation varied strongly over the two different catalysts.
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| 25. |
- Kusar, H. M. J., et al.
(author)
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Catalytic combustion of gasified refuse-derived fuel
- 2003
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In: Applied Catalysis B. - 0926-3373 .- 1873-3883. ; 45:1, s. 1-11
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Journal article (peer-reviewed)abstract
- The catalytic combustion of gasified refuse-derived fuel (RDF), i.e. a low heating-value (LHV) gas containing H-2, CO and CH4 as combustible components, has been studied and compared with the combustion of methane. Two metal oxide catalysts, i.e. a spinel and a hexaaluminate, and three noble metal catalysts were tested. The results show that the Pd-based catalysts were the most active both for the gasified waste, i.e. RDF and methane. Incorporating an active support such as LaMnAl11O19 enhances the catalytic activity for methane in gasified waste. Substituting Mn into the crystal lattice of the spinel also increased the catalytic activity for H-2 and CO, while the methane activity remained low. The formation of NOX from fuel-bound nitrogen was investigated by adding NH3 to the gas stream. The metal oxide catalysts showed a higher selectivity for oxidising NH3 into N-2 than the catalysts containing precious metals. The spinel materials have high thermal stability and are comparable to the hexaaluminates confirming that they could be promising as washcoat materials to avoiding sintering at high temperatures.
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| 26. |
- Kusar, H. M. J., et al.
(author)
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Selective catalytic oxidation of NH3 to N-2 for catalytic combustion of low heating value gas under lean/rich conditions
- 2005
-
In: Applied Catalysis B. - : Elsevier BV. - 0926-3373 .- 1873-3883. ; 58:02-jan, s. 25-32
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Journal article (peer-reviewed)abstract
- The selective catalytic oxidation (SCO) of ammonia to nitrogen has been examined over 5% Fe/Al2O3, 5% Mn/Al2O3, 20% Cuo/Al2O3, 1% Pt/20% CuO/Al2O3, 2% Rh/Al2O3 and a Fe zeolite (Fe-SH-27) under fuel-lean and fuel-rich conditions in a monolith lab-scale reactor. For simulating fuel-bound nitrogen in a low heating value (LHV) gas 400 ppm NH3 was added to the test gas. The SCO performance of the catalysts was tested both with and without water added to the gas stream. For SCO under fuel-lean conditions the Fe-zeolite catalyst exhibited the lowest NO, yield. For SCO under fuel-rich conditions the 20% CuO/Al2O3 was superior with close to zero NO, formation.
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| 27. |
- Peña, Pablo, et al.
(author)
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Interleukin 4 induces apoptosis of acute myeloid leukemia cells in a Stat6 dependent manner
- 2018
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In: Leukemia. - : Springer Science and Business Media LLC. - 1476-5551 .- 0887-6924. ; 32:3, s. 588-596
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Journal article (peer-reviewed)abstract
- Cytokines provide signals that regulate immature normal and acute myeloid leukemia (AML) cells in the bone marrow microenvironment. We here identify interleukin 4 (IL4) as a selective inhibitor of AML cell growth and survival in a cytokine screen using fluorescently labeled AML cells. RNA-sequencing of the AML cells revealed an IL4-induced upregulation of Stat6 target genes and enrichment of apoptosis-related gene expression signatures. Consistent with these findings, we found that IL4 stimulation of AML cells induced Stat6 phosphorylation and that disruption of Stat6 using CRISPR/Cas9-genetic engineering rendered cells partially resistant to IL4-induced apoptosis. To evaluate whether IL4 inhibits AML cells in vivo, we expressed IL4 ectopically in AML cells transplanted into mice and also injected IL4 into leukemic mice; both strategies resulted in the suppression of the leukemia cell burden and increased survival. Notably, IL4 exposure caused reduced growth and survival of primary AML CD34(+)CD38(-) patient cells from several genetic subtypes of AML, whereas normal stem and progenitor cells were less affected. The IL4-induced apoptosis of AML cells was linked to Caspase-3 activation. Our results demonstrate that IL4 selectively induces apoptosis of AML cells in a Stat6-dependent manner, findings that may translate into new therapeutic opportunities in AML.Leukemia accepted article preview online, 18 August 2017. doi:10.1038/leu.2017.261.
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| 28. |
- Persson, Katarina, et al.
(author)
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Influence of molar ratio on Pd-Pt catalysts for methane combustion
- 2006
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In: Journal of Catalysis. - : Elsevier BV. - 0021-9517. ; 243:1, s. 14-24
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Journal article (peer-reviewed)abstract
- The catalytic oxidation of methane was investigated over six catalysts with different palladium and platinum molar ratios. The catalysts were characterised by TEM, EDS, XPS, PXRD and temperature-programmed oxidation. The results suggest that in the bimetallic catalysts, an alloy between Pd and Pt was formed in close contact with the PdO phase, with an exception for the Pt-rich catalyst, where no PdO was observed. It was found that the molar ratio between palladium and platinum clearly influences both the activity and the stability of methane conversion. By adding small amounts of platinum into the palladium catalyst, improved activity was obtained in comparison with the monometallic palladium catalyst. However, higher amounts of platinum are required for stabilising the methane conversion. The most promising catalysts with respect to both activity and stability were Pd67Pt33 and Pd50Pt50. The platinum-rich catalyst showed very poor activity for methane conversion.
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| 29. |
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| 30. |
- Thevenin, P. O., et al.
(author)
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Deactivation of high temperature combustion catalysts
- 2001
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In: Applied Catalysis A. - 0926-860X .- 1873-3875. ; 212:02-jan, s. 189-197
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Journal article (peer-reviewed)abstract
- The main objective of catalytic combustion is to attain a flame temperature 300-400 Klower than in thermal or non-catalyzed combustion; this substantially reduces the direct combination of nitrogen and oxygen in air to form the so-called thermal NOx. In this way, catalytic combustion is a preventive solution to the problem of nitrogen oxides emissions. The focus of attention here is its application in gas turbines, both for power production and for transportation by road, sea and air. Any catalyst for catalytic combustion, however, has to face extreme demands: continuous operation above 1000 degreesC in the presence of oxygen and steam for preferably 30,000 h, resistance to poisons in the fuel and/or process air, and ability to withstand large thermal and mechanical shocks. While material/catalyst advances are still inadequate, systems engineering is coming to the rescue by developing multiple-monolith catalyst systems and the so-called hybrid reactors. The deactivation of catalyst supports, washcoats, and active materials is briefly reviewed here: sintering, vaporization, phase transformation, thermal shock and poisoning.
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| 31. |
- von Palffy, Sofia, et al.
(author)
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A high-content cytokine screen identifies myostatin propeptide as a positive regulator of primitive chronic myeloid leukemia cells
- 2020
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In: Haematologica. - : Ferrata Storti Foundation (Haematologica). - 0390-6078 .- 1592-8721. ; 105:8, s. 2095-2104
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Journal article (peer-reviewed)abstract
- Aberrantly expressed cytokines in the bone marrow (BM) niche are increasingly recognized as critical mediators of survival and expansion of leukemic stem cells. To identify regulators of primitive chronic myeloid leukemia (CML) cells, we performed a high-content cytokine screen using primary CD34+ CD38low chronic phase CML cells. Out of the 313 unique human cytokines evaluated, 11 were found to expand cell numbers ≥2-fold in a 7-day culture. Focusing on novel positive regulators of primitive CML cells, the myostatin antagonist myostatin propeptide gave the largest increase in cell expansion and was chosen for further studies. Herein, we demonstrate that myostatin propeptide expands primitive CML and normal BM cells, as shown by increased colony-forming capacity. For primary CML samples, retention of CD34-expression was also seen after culture. Furthermore, we show expression of MSTN by CML mesenchymal stromal cells, and that myostatin propeptide has a direct and instant effect on CML cells, independent of myostatin, by demonstrating binding of myostatin propeptide to the cell surface and increased phosphorylation of STAT5 and SMAD2/3. In summary, we identify myostatin propeptide as a novel positive regulator of primitive CML cells and corresponding normal hematopoietic cells.
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| 32. |
- Vu, Ly P., et al.
(author)
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Functional screen of MSI2 interactors identifies an essential role for SYNCRIP in myeloid leukemia stem cells
- 2017
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In: Nature Genetics. - : Springer Science and Business Media LLC. - 1061-4036 .- 1546-1718. ; 49:6, s. 866-875
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Journal article (peer-reviewed)abstract
- The identity of the RNA-binding proteins (RBPs) that govern cancer stem cells remains poorly characterized. The MSI2 RBP is a central regulator of translation of cancer stem cell programs. Through proteomic analysis of the MSI2-interacting RBP network and functional shRNA screening, we identified 24 genes required for in vivo leukemia. Syncrip was the most differentially required gene between normal and myeloid leukemia cells. SYNCRIP depletion increased apoptosis and differentiation while delaying leukemogenesis. Gene expression profiling of SYNCRIP-depleted cells demonstrated a loss of the MLL and HOXA9 leukemia stem cell program. SYNCRIP and MSI2 interact indirectly though shared mRNA targets. SYNCRIP maintains HOXA9 translation, and MSI2 or HOXA9 overexpression rescued the effects of SYNCRIP depletion. Altogether, our data identify SYNCRIP as a new RBP that controls the myeloid leukemia stem cell program. We propose that targeting these RBP complexes might provide a novel therapeutic strategy in leukemia.
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