| 1. |
- Montes, V., et al.
(author)
-
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.
|
|
| 2. |
- Berg, M., et al.
(author)
-
Catalytic combustion of low heating value gas mixtures : comparison between laboratory and pilot scale tests
- 2000
-
In: Catalysis Today. - 0920-5861 .- 1873-4308. ; 59:02-jan, s. 117-130
-
Journal article (peer-reviewed)abstract
- Catalytic combustion of low heating value fuels is a promising method for electricity production combining the use of a renewable fuel with ultra-low emissions. In the present work, catalytic combustion of a low heating value gas has been studied over monolithic catalysts in an atmospheric 30 kW pilot catalytic combustor connected to a wood pellet gasifier. The results have been compared to similar tests with a model gas mixture and a series of test in a laboratory scale reactor for monolithic samples. Various catalyst configurations have been tested, such as precious metal-based catalyst impregnated on modified alumina washcoats and hexaaluminate washcoats. Cordierite monoliths with various cells per square inch were used as supports, but hexaaluminate extruded monoliths were also used. The catalysts were combined in different segment series. The results show that it is possible to ignite the low heating value gas at compressor outlet temperatures without the use of pre-burners over precious metal catalysts. Generally, trends and phenomena obtained in laboratory reactor operating close to isothermal could be confirmed in the pilot operating at close to adiabatic conditions. Further results, such as deactivation by sulphur compounds, fuel-NOx conversion and emissions of carbon monoxide and total hydrocarbons, are addressed in the paper.
|
|
| 3. |
- Johansson, E. M., et al.
(author)
-
Development of hexaaluminate catalysts for combustion of gasified biomass in gas turbines
- 2002
-
In: Journal of engineering for gas turbines and power. - : ASME International. - 0742-4795 .- 1528-8919. ; 124:2, s. 235-238
-
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.
|
|
| 4. |
- Kusar, H. M. J., et al.
(author)
-
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
-
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.
|
|
| 5. |
- 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.
|
|
| 6. |
- Peña, Pablo, et al.
(author)
-
Interleukin 4 induces apoptosis of acute myeloid leukemia cells in a Stat6 dependent manner
- 2018
-
In: Leukemia. - : Springer Science and Business Media LLC. - 1476-5551 .- 0887-6924. ; 32:3, s. 588-596
-
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.
|
|
| 7. |
- Vu, Ly P., et al.
(author)
-
Functional screen of MSI2 interactors identifies an essential role for SYNCRIP in myeloid leukemia stem cells
- 2017
-
In: Nature Genetics. - : Springer Science and Business Media LLC. - 1061-4036 .- 1546-1718. ; 49:6, s. 866-875
-
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.
|
|
| 8. |
- Arbajian, Elsa, et al.
(author)
-
In-depth genetic analysis of sclerosing epithelioid fibrosarcoma reveals recurrent genomic alterations and potential treatment targets
- 2017
-
In: Clinical Cancer Research. - 1078-0432. ; 23:23, s. 7426-7434
-
Journal article (peer-reviewed)abstract
- PURPOSE: Sclerosing epithelioid fibrosarcoma (SEF) is a highly aggressive soft tissue sarcoma closely related to low-grade fibromyxoid sarcoma (LGFMS). Some tumors display morphological characteristics of both SEF and LGFMS, so called hybrid SEF/LGFMS. Despite the overlap of gene fusion variants between these two tumor types, SEF is much more aggressive. The present study aimed to further characterize SEF and hybrid SEF/LGFMS genetically in order to better understand the role of the characteristic fusion genes and possible additional genetic alterations in tumorigenesis.EXPERIMENTAL DESIGN: We performed whole exome sequencing, single nucleotide polymorphism (SNP) array analysis, RNA-sequencing (RNA-seq), global gene expression analyses and/or IHC on a series of 13 SEFs and 6 hybrid SEF/LGFMS. We also expressed the FUS-CREB3L2 and EWSR1-CREB3L1 fusion genes conditionally in a fibroblast cell line; these cells were subsequently analyzed by RNA-seq and expression of the CD24 protein was assessed by FACS analysis.RESULTS: The SNP array analysis detected a large number of structural aberrations in SEF and SEF/LGFMS, many of which were recurrent, notably DMD microdeletions. RNA-seq identified FUS-CREM and PAX5-CREB3L1 as alternative fusion genes in one SEF each. CD24 was strongly upregulated, presumably a direct target of the fusion proteins. This was further confirmed by the gene expression analysis and FACS analysis on Tet-On 3G cells expressing EWSR1-CREB3L1.CONCLUSIONS: While gene fusions are the primary tumorigenic events in both SEF and LGFMS, additional genomic changes explain the differences in aggressiveness and clinical outcome between the two types. CD24 and DMD constitute potential therapeutic targets.
|
|
| 9. |
- Eriksson, Sara, et al.
(author)
-
Experimental and numerical investigation of supported rhodium catalysts for partial oxidation of methane in exhaust gas diluted reaction mixtures
- 2007
-
In: Chemical Engineering Science. - : Elsevier BV. - 0009-2509 .- 1873-4405. ; 62:15, s. 3991-4011
-
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.
|
|
| 10. |
- Eriksson, Sara, et al.
(author)
-
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
-
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.
|
|
