| 1. |
- Dey, Lankeswar, et al.
(författare)
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Authenticating the Presence of a Relativistic Massive Black Hole Binary in OJ 287 Using Its General Relativity Centenary Flare : Improved Orbital Parameters
- 2018
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Ingår i: Astrophysical Journal. - : American Astronomical Society. - 0004-637X .- 1538-4357. ; 866:1
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Tidskriftsartikel (refereegranskat)abstract
- Results from regular monitoring of relativistic compact binaries like PSR 1913+16 are consistent with the dominant (quadrupole) order emission of gravitational waves (GWs). We show that observations associated with the binary black hole (BBH) central engine of blazar OJ 287 demand the inclusion of gravitational radiation reaction effects beyond the quadrupolar order. It turns out that even the effects of certain hereditary contributions to GW emission are required to predict impact flare timings of OJ 287. We develop an approach that incorporates this effect into the BBH model for OJ 287. This allows us to demonstrate an excellent agreement between the observed impact flare timings and those predicted from ten orbital cycles of the BBH central engine model. The deduced rate of orbital period decay is nine orders of magnitude higher than the observed rate in PSR 1913+16, demonstrating again the relativistic nature of OJ 287's central engine. Finally, we argue that precise timing of the predicted 2019 impact flare should allow a test of the celebrated black hole no-hair theorem at the 10% level.
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| 2. |
- Adewumi, Oluseun, et al.
(författare)
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Characterization of human embryonic stem cell lines by the International Stem Cell Initiative
- 2007
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Ingår i: Nature Biotechnology. - : Springer Science and Business Media LLC. - 1087-0156 .- 1546-1696. ; 25:7, s. 803-816
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Tidskriftsartikel (refereegranskat)abstract
- The International Stem Cell Initiative characterized 59 human embryonic stem cell lines from 17 laboratories worldwide. Despite diverse genotypes and different techniques used for derivation and maintenance, all lines exhibited similar expression patterns for several markers of human embryonic stem cells. They expressed the glycolipid antigens SSEA3 and SSEA4, the keratan sulfate antigens TRA-1-60, TRA-1-81, GCTM2 and GCT343, and the protein antigens CD9, Thy1 (also known as CD90), tissue- nonspecific alkaline phosphatase and class 1 HLA, as well as the strongly developmentally regulated genes NANOG, POU5F1 (formerly known as OCT4), TDGF1, DNMT3B, GABRB3 and GDF3. Nevertheless, the lines were not identical: differences in expression of several lineage markers were evident, and several imprinted genes showed generally similar allele-specific expression patterns, but some gene-dependent variation was observed. Also, some female lines expressed readily detectable levels of XIST whereas others did not. No significant contamination of the lines with mycoplasma, bacteria or cytopathic viruses was detected.
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| 3. |
- Graco-Roza, Caio, et al.
(författare)
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Distance decay 2.0 – A global synthesis of taxonomic and functional turnover in ecological communities
- 2022
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Ingår i: Global Ecology and Biogeography. - : Wiley. - 1466-822X .- 1466-8238. ; 31:7, s. 1399-1421
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Tidskriftsartikel (refereegranskat)abstract
- Aim: Understanding the variation in community composition and species abundances (i.e., beta-diversity) is at the heart of community ecology. A common approach to examine beta-diversity is to evaluate directional variation in community composition by measuring the decay in the similarity among pairs of communities along spatial or environmental distance. We provide the first global synthesis of taxonomic and functional distance decay along spatial and environmental distance by analysing 148 datasets comprising different types of organisms and environments.Location: Global.Time period: 1990 to present.Major taxa studied: From diatoms to mammals.Method: We measured the strength of the decay using ranked Mantel tests (Mantel r) and the rate of distance decay as the slope of an exponential fit using generalized linear models. We used null models to test whether functional similarity decays faster or slower than expected given the taxonomic decay along the spatial and environmental distance. We also unveiled the factors driving the rate of decay across the datasets, including latitude, spatial extent, realm and organismal features.Results: Taxonomic distance decay was stronger than functional distance decay along both spatial and environmental distance. Functional distance decay was random given the taxonomic distance decay. The rate of taxonomic and functional spatial distance decay was fastest in the datasets from mid-latitudes. Overall, datasets covering larger spatial extents showed a lower rate of decay along spatial distance but a higher rate of decay along environmental distance. Marine ecosystems had the slowest rate of decay along environmental distances.Main conclusions: In general, taxonomic distance decay is a useful tool for biogeographical research because it reflects dispersal-related factors in addition to species responses to climatic and environmental variables. Moreover, functional distance decay might be a cost-effective option for investigating community changes in heterogeneous environments.
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| 4. |
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| 5. |
- Dotto, Guilherme Luiz, et al.
(författare)
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Adsorption of rare earth elements (Ce3+, La3+, and Nd3+) and recovery from phosphogypsum leachate using a novel ZSM-5 zeolite
- 2024
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Ingår i: Colloids and Surfaces A. - : Elsevier. - 0927-7757 .- 1873-4359. ; 698
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Tidskriftsartikel (refereegranskat)abstract
- ZSM-5 zeolite is a multifunctional material highly efficient for adsorbing ions. Our ZSM-5 was synthesized by employing a nucleating gel as a structure-directing agent, followed by homogenization and hydrothermal treatment. The as-prepared ZSM-5 was physicochemically characterized to assess its properties. Next, the as-prepared zeolite was employed as an adsorbent to remove rare earth elements, REEs from synthetic solutions and real phosphogypsum leachate under batch mode operation. As expected, the ZSM-5 adsorbent was discovered to be highly microporous with abundant surface functionalities, which could positively impact REE adsorption. The adsorption data indicated a high affinity between ZSM-5 and all three REEs with rapid kinetics and high adsorption capacities. The modeling study suggested that the adsorption kinetic data were well fitted by Avrami-fractional order, and Liu described the equilibrium data. The maximum adsorption capacity for Ce3+, La3+, and Nd3+ were 99.42 mg g−1, 96.43 mg g−1, 118.10 mg g−1, respectively. Further, the thermodynamic analysis revealed that the interaction between ZSM-5 and Ce3+, La3+, and Nd3+ was favorable, spontaneous, and endothermic. The efficiency of ZSM-5 adsorbent was also studied in recovering several REEs from leachate of phosphogypsum wastes, and the data results proved its potency to do so. The findings reported in this work support the idea that ZSM-5 can be successfully used as an adsorbent to recover REEs from synthetic and real samples.
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| 6. |
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| 7. |
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| 8. |
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| 9. |
- Mikkola, H, et al.
(författare)
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Lentivirus gene transfer in murine hematopoietic progenitor cells is compromised by a delay in proviral integration and results in transduction mosaicism and heterogeneous gene expression in progeny cells
- 2000
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Ingår i: Journal of Virology. - : American Society for Microbiology. - 0022-538X .- 1098-5514. ; 74:24, s. 8-11911
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Tidskriftsartikel (refereegranskat)abstract
- Human immunodeficiency virus type 1-based lentivirus vectors containing the green fluorescent protein (GFP) gene were used to transduce murine Lin(-) c-kit(+) Sca1(+) primitive hematopoietic progenitor cells. Following transduction, the cells were plated into hematopoietic progenitor cell assays in methylcellulose and the colonies were scored for GFP positivity. After incubation for 20 h, lentivirus vectors transduced 27.3% +/- 6.7% of the colonies derived from unstimulated target cells, but transduction was more efficient when the cells were supported with stem cell factor (SCF) alone (42. 0% +/- 5.5%) or SCF, interleukin-3 (IL-3), and IL-6 (53.3 +/- 1.8%) during transduction. The, vesicular stomatitis virus glycoprotein-pseudotyped MGIN oncoretrovirus control vector required IL-3, IL-6, and SCF for significant transduction (39.3 +/- 9.4%). Interestingly, only a portion of the progeny cells within the lentivirus-transduced methylcellulose colonies expressed GFP, in contrast to the homogeneous expression in oncoretrovirus-transduced colonies. Secondary plating of the primary GFP(+) lentivirus vector-transduced colonies revealed vector PCR(+) GFP(+) (42%), vector PCR(-) GFP(-) (46%), and vector PCR(+) GFP(-) (13%) secondary colonies, indicating true genetic mosaicism with respect to the viral genome in the progeny cells. The degree of vector mosaicism in individual colonies could be reduced by extending the culture time after transduction and before plating into the clonal progenitor cell assay, indicating a delay in the lentiviral integration process. Furthermore, supplementation with exogenous deoxynucleoside triphosphates during transduction decreased mosaicism within the colonies. Although cytokine stimulation during transduction correlates with higher transduction efficiency, rapid cell division after transduction may result in loss of the viral genome in the progeny cells. Therefore, optimal transduction may require activation without promoting intense cell proliferation prior to vector integration.
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| 10. |
- Mikkola, T. M., et al.
(författare)
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Influence of long-term postmenopausal hormone-replacement therapy on estimated structural bone strength: A study in discordant monozygotic twins
- 2011
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Ingår i: Journal of Bone and Mineral Research. - : Wiley. - 0884-0431. ; 26:3, s. 546-52
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Tidskriftsartikel (refereegranskat)abstract
- Although postmenopausal hormone-replacement therapy (HRT) is known to prevent fractures, knowledge on the influence of long-term HRT on bone strength and its determinants other than areal bone mineral density is scarce. This study used a genetically controlled design with 24 monozygotic female twin pairs aged 54 to 72 years in which one cotwin was using HRT (mean duration 8 years) and the other had never used HRT. Estimated bone strength, cross-sectional area, volumetric bone mineral density, bone mineral mass, and cross-sectional density and mass distributions were assessed in the tibial shaft, distal tibia, and distal radius with peripheral computed tomography (pQCT). In the tibial shaft, HRT users had 9% [95% confidence interval (CI) 3%-15%] higher estimated bending strength than their nonusing cotwins. Larger cortical area and higher cortical bone mineral density accounted for this difference. The cortex was larger in the HRT users in the endocortical region. In the distal tibia, estimated compressive strength was 24% (95% CI 9%-40%) higher and in the distal radius 26% (95% CI 11%-41%) higher in the HRT users than in their nonusing cotwins owing to higher volumetric bone mineral density. No difference between users and nonusers was observed in total bone cross-sectional area in any measured bone site. The added mineral mass in the HRT users was distributed evenly within and between bone sites. In postmenopausal women, long-term HRT preserves estimated bone strength systemically by preventing bone mineral loss similarly in body weight-loaded and non-weight-loaded bone. (c) 2011 American Society for Bone and Mineral Research.
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| 11. |
- Pezoa-Conte, R., et al.
(författare)
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Deconstruction of the green alga Ulva rigida in ionic liquids : closing the mass balance
- 2015
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Ingår i: Algal Research. - : Elsevier. - 2211-9264. ; 12, s. 262-273
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Tidskriftsartikel (refereegranskat)abstract
- Algae are known to grow at high rates compared to terrestrial plants that contain comparable amounts of carbohydrates by weight. Therefore, this renders them attractive in terms of any biorefinery concept. In this work the green alga Ulva rigida, containing 40 wt.% of carbohydrates was pretreated with a switchable ionic liquid (SIL), distillable ionic liquid (DIL) and low-viscosity ionic liquid (LVIL). The SIL DBU–MEA–SO2 was prepared from a mixture of mono-ethanolamine (MEA) and 1,8-diazabicyclo-[5,4,0]-undec-7-ene (DBU) that was coupled with sulfur dioxide (SO2), whereas the DIL [TMGH+][EtCO2−] (1,1,3,3-tetramethylguanidine propionate) was synthesized by a simple acid–base neutralization reaction. Consequently, the LVIL [HDBU+][5OF−] protonated 1,8-diazabicyclo-[5,4,0]-undec-7-ene- 2,2,3,3,4,4,5,5-octafluoro-1-pentoxide was used as received. The treatments were carried out in the temperature range of 100–160 °C for 6 h. The products obtained after the treatments were analyzed using different techniques like ICP, OES, SEM, TEM, TGA, FTIR and carbohydrate determination by GC. Upon treatment with DIL up to 67 wt.% of carbohydrates could be dissolved. For the first time, processing of U. rigida was carried out in ionic liquids so that the mass balance of the process was obtained. It can be concluded that 1,1,3,3-tetramethylguanidine propionate shows significant potential when aiming at releasing carbohydrates from algal biomass that, consequently, can be applied in the production of platform chemicals and/or biofuels such as bioethanol.
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| 12. |
- Schlosser, M, et al.
(författare)
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HIV-1 Sub-Subtype A6: Settings for Normalised Identification and Molecular Epidemiology in the Southern Federal District, Russia
- 2020
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Ingår i: Viruses. - : MDPI AG. - 1999-4915. ; 12:4
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Tidskriftsartikel (refereegranskat)abstract
- Russia has one of the largest and fastest growing HIV epidemics. However, epidemiological data are scarce. Sub-subtype A6 is most prevalent in Russia but its identification is challenging. We analysed protease/reverse transcriptase-, integrase-sequences, and epidemiological data from 303 patients to develop a methodology for the systematisation of A6 identification and to describe the HIV epidemiology in the Russian Southern Federal District. Drug consumption (32.0%) and heterosexual contact (27.1%) were the major reported transmission risks. This study successfully established the settings for systematic identification of A6 samples. Low frequency of subtype B (3.3%) and large prevalence of sub-subtype A6 (69.6%) and subtype G (23.4%) were detected. Transmitted PI- (8.8%) and NRTI-resistance (6.4%) were detected in therapy-naive patients. In therapy-experienced patients, 17.3% of the isolates showed resistance to PIs, 50.0% to NRTI, 39.2% to NNRTIs, and 9.5% to INSTIs. Multiresistance was identified in 52 isolates, 40 corresponding to two-class resistance and seven to three-class resistance. Two resistance-associated-mutations significantly associated to sub-subtype A6 samples: A62VRT and G190SRT. This study establishes the conditions for a systematic annotation of sub-subtype A6 to normalise epidemiological studies. Accurate knowledge on South Russian epidemiology will allow for the development of efficient regional frameworks for HIV-1 infection management.
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| 13. |
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| 14. |
- Woods, N B, et al.
(författare)
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Lentiviral gene transfer into primary and secondary NOD/SCID repopulating cells
- 2000
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Ingår i: Blood. - 0006-4971. ; 96:12, s. 33-3725
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Tidskriftsartikel (refereegranskat)abstract
- The ability of lentiviral vectors to transfer genes into human hematopoietic stem cells was studied, using a human immunodeficiency virus 1 (HIV-1)-derived vector expressing the green fluorescence protein (GFP) downstream of the phosphoglycerate kinase (PGK) promoter and pseudotyped with the G protein of vesicular stomatitis virus (VSV). High-efficiency transduction of human cord blood CD34(+) cells was achieved after overnight incubation with vector particles. Sixteen to 28 percent of individual colony-forming units granulocyte-macrophage (CFU-GM) colonies derived from cord blood CD34(+) cells were positive by polymerase chain reaction (PCR) for the GFP gene. The transduction efficiency of SCID-repopulating cells (SRC) within the cord blood CD34(+) population was assessed by serial transplantation into nonobese diabetic/severe combined immunodeficient (NOD/SCID) mice. When 400,000 cord blood CD34(+) cells were transplanted into primary recipients, all primary and secondary recipients contained and expressed the transgene. Over 50% of CFU-GM colonies derived from the bone marrow of these primary and secondary recipients contained the vector on average as determined by PCR. Transplantation of transduced cells in limiting dilution generated GFP(+) lymphoid and myeloid progeny cells that may have arisen from a single SRC. Inverse PCR analysis was used to amplify vector-chromosomal junctional fragments in colonies derived from SRC and confirmed that the vector was integrated. These results show that lentiviral vectors can efficiently transduce very primitive human hematopoietic progenitor and stem cells. (Blood. 2000;96:3725-3733)
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| 15. |
- Aid, T., et al.
(författare)
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Saccharification of lignocellulosic biomasses via ionic liquid pretreatment
- 2016
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Ingår i: Industrial crops and products (Print). - : Elsevier. - 0926-6690 .- 1872-633X. ; 92, s. 336-341
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Tidskriftsartikel (refereegranskat)abstract
- The current work focuses on the pretreatment efficiency of ILs combined with heat for woody biomass consisting of spruce, birch and pine as well as winter wheat straw. The latter was investigated as a comparison and with the aim to enhance its digestibility during enzymatic hydrolysis whereby the influence of IL-treatment to cellulose resistance for hydrolysis was investigated. Considering the wood species, the most common and industrially important wood species in Northern Europe were chosen in the present work and the goal was to obtain fermentable sugars and their degradation product, i.e. 5-hydroxymethylfurfural (5-HMF), which is known valuable platform chemical. Further, the differences in the yields of IL-obtainable carbohydrates between these species were studied. The highest sugar yields were obtained to glucose in the case of spruce and arabinose in the case of pine sapwood, 12.07 and 7.72 mmol/L, respectively. The highest 5-HMF yield was obtained for spruce heartwood (9.18 mmol/L) with longer treatment time, such as 100h. However, regarding woody biomass, the present work was focused more on the study and analysis of the IL-containing liquid part, wood hydrolysate, after IL-treatment aiming to answer the analysis challenges related to this fraction.
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| 16. |
- Anugwom, I, et al.
(författare)
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Selective Extraction of Hemicelluloses from Spruce using Switchable Ionic Liquids
- 2012
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Ingår i: Carbohydrate Polymers. - : Elsevier. - 0144-8617 .- 1879-1344. ; 87:3, s. 2005-2011
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Tidskriftsartikel (refereegranskat)abstract
- Switchable Ionic Liquids (SILs) made from alcohols, either hexanol or butanol, and CO2 together with an amidine (1,8-diazabicyclo-[5.4.0]-undec-7-ene (DBU)) were investigated as dissolution/fractionation solvents for wood material. Both native spruce (Picea abies), and pre-extracted spruce were treated with either butanol SIL (SIL1) or hexanol SIL (SIL 2) for 5 days at 55 °C under normal pressure. The SILs were formed by bubbling CO2 through an equimolar mixture of either 1-hexanol or 1-butanol and DBU. The viscosity of the mixture increased from 7.1 mPas to 2980 mPas for SIL 2 and 5.1 to 1600 mPas for SIL 1. Melting points of the SILs 1 and 2 were at 8 and 14 °C, respectively. After the treatment time (5 days), the undissolved fraction contained 38 wt % less hemicelluloses compared to native spruce. There was an increase in the glucose content of the milled spruce treated with both SILs, since the milling step reduced the cellulose crystallinity of the wood and facilitated an easier SIL access into the wood. The solvents were very neutral in terms of lignin removal. Consequently, only about 2% of the lignin was removed from native wood. Moreover, a priori removal of the wood extractives did not influence the lignin removal. Highlights► Switchable Ionic Liquids made from, either hexanol or butanol, and CO2 together with an amidine (DBU) were studies as dissolution/fractionation solvents for spruce wood. ► After the treatment undissolved fraction contained 38 wt-% less hemicelluloses. ► We conclude that Switchable ionic liquids are effective solvent for fractionation of wood material, and they are easily recycled and can be reused.
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| 17. |
- Biasi, P., et al.
(författare)
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Revealing the role of bromide in the H2O2 direct synthesis with the catalyst wet pretreatment method (CWPM)
- 2017
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Ingår i: AIChE Journal. - : American Institute of Chemical Engineers. - 0001-1541 .- 1547-5905. ; 63:1, s. 32-42
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Tidskriftsartikel (refereegranskat)abstract
- A tailor-made Pd0/K2621 catalyst was subjected to post synthesis modification via a wet treatment procedure. The aimwas the understanding of the role of promoters and how—if any—improvements could be qualitatively related to the cat-alyst performance for the H2O2direct synthesis. The Catalyst Wet Pretreatment Method was applied in different metha-nolic solutions containing H2O2, NaBr, and H3PO4, either as single modifiers or as a mixture. The catalyst wascharacterized by Transmission Electron Microscopy and X-ray Photoelectron Spectroscopy. It was concluded that themodified catalysts give rise to higher selectivities compared to the pristi ne reference catalyst thus opening a possibilityto exclude the addit ion of the undesirable selectivity enhancers in the reaction medium. This work provides original evi-dence on the role of promoter s, especially bromide, allowing the formulation of a new reaction mechanism for one ofthe most challenging reactions recognized by the world.
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| 18. |
- Binios, A., et al.
(författare)
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Moon compact satellite for hazard assessment (MOOCHA) - Proposing an international Earth-Moon small satellite constellation
- 2019
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Ingår i: Proceedings of the International Astronautical Congress, IAC. - : International Astronautical Federation, IAF.
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Konferensbidrag (refereegranskat)abstract
- The recent developments in space exploration have reinstated the Moon as a primary target for near future space missions. The principal reasons include the Moon being the closest test bed and analogue for planetary space missions and the prospect of scientific lunar bases and orbital stations within the next decade. Previous space missions have vastly improved our understanding on hazards of human spaceflights but not fully regarding the threats affecting a prospective lunar base or orbital station. The micrometeorite hazard has been partially addressed as an issue which can potentially impact both astronauts' health and safety as well as create issues for lunar bases and orbital stations, such as degradation or permanent damage of equipment and facilities. The current understanding is based partly on dust and micrometeoroid flux measurements and impact flash observations. However, observations with improved spatial and temporal resolution are imperative for advancing existing hazard models. In this paper, a mission concept of a constellation of nanosatellites is proposed that can both observe larger parts of cis-lunar and trans-lunar space while providing higher temporal resolution. Nanosatellite missions are a cost-effective solution providing data for significant improvement of our current understanding of lunar micrometeoroid flux models, and thus directly the scale of hazards caused by micrometeoroid impacts to future lunar missions. Additionally, such a distributed constellation mission will offer countless opportunities for academia, students and young scientists worldwide. The mission concept (Moon Compact Satellite for Hazard Assessment - MOOCHA) is a result of the Nordic-European Astrobiology Campus Summer School 2018 themed “Microsatellites in Planetary and Atmospheric Research” and was further developed during the 2019 follow-up summer school “Design of Small Satellite Missions for Planetary Studies”, both taking place in Tartu, Estonia and co-organized by the Stockholm University Astrobiology Centre, the University of Tartu, the European Astrobiology Campus and the Nordic Network of Astrobiology and supported by European Union's European Regional Development Fund and Estonia.
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| 19. |
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| 20. |
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| 21. |
- Elo, T., et al.
(författare)
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Ectodysplasin target gene Fgf20 regulates mammary bud growth and ductal invasion and branching during puberty
- 2017
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Ingår i: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 7
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Tidskriftsartikel (refereegranskat)abstract
- Mammary gland development begins with the appearance of epithelial placodes that invaginate, sprout, and branch to form small arborized trees by birth. The second phase of ductal growth and branching is driven by the highly invasive structures called terminal end buds (TEBs) that form at ductal tips at the onset of puberty. Ectodysplasin (Eda), a tumor necrosis factor-like ligand, is essential for the development of skin appendages including the breast. In mice, Eda regulates mammary placode formation and branching morphogenesis, but the underlying molecular mechanisms are poorly understood. Fibroblast growth factor (Fgf) receptors have a recognized role in mammary ductal development and stem cell maintenance, but the ligands involved are ill-defined. Here we report that Fgf20 is expressed in embryonic mammary glands and is regulated by the Eda pathway. Fgf20 deficiency does not impede mammary gland induction, but compromises mammary bud growth, as well as TEB formation, ductal outgrowth and branching during puberty. We further show that loss of Fgf20 delays formation of Eda-induced supernumerary mammary buds and normalizes the embryonic and postnatal hyperbranching phenotype of Eda overexpressing mice. These findings identify a hitherto unknown function for Fgf20 in mammary budding and branching morphogenesis.
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| 22. |
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| 23. |
- Freites Aguilera, A., et al.
(författare)
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Screening of heterogeneous catalysts for microwave assisted epoxidation of vegetable oils
- 2018
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Ingår i: 23rd International Congress of Chemical and Process Engineering, CHISA 2018 and 21st Conference on Process Integration, Modelling and Optimisation for Energy Saving and Pollution Reduction, PRES 2018. - : Czech Society of Chemical Engineering. - 9781510881198 ; , s. 54-55
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Konferensbidrag (refereegranskat)
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| 24. |
- Golets, Mikhail, 1987-, et al.
(författare)
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Continuous production of the renewable ρ-cymene from α-pinene
- 2013
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Ingår i: Journal of Catalysis. - : Elsevier. - 0021-9517 .- 1090-2694. ; 307, s. 305-315
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Tidskriftsartikel (refereegranskat)abstract
- The aim of this work was to demonstrate the feasibility to produce ρ-cymene, an important commodity chemical, in a continuous, one-pot reaction system from abundant α-pinene, available e.g. as a by-product of pulping industry. The isomerization reactions of α-pinene over bimetallic heterogeneous catalysts, 3 and 5 wt% Pd–Zn (1:1, 1:4, 4:1, 1:0, and 0:1), supported on Al-SBA15 were studied. The principal reaction products were identified as ρ- and m-cymenes, limonene, camphene, and ρ-menthene, respectively. The highest concentration of ρ-cymene reached 77 wt% under the optimized reaction conditions: 300 °C and α-pinene feed of 0.03 mL/min. Two main reaction pathways toward ρ- and m-cymenes were described, and a mechanistic kinetic model, based on a plausible reaction network in line with Langmuir–Hinshelwood approach, was developed. The catalyst characterization revealed the reduction in Pd(II) sites, catalyst coking, and decline of surface area over the course of time. The catalyst recovery and reuse was addressed.
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| 25. |
- Hamaguchi, I, et al.
(författare)
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Lentivirus vector gene expression during ES cell-derived hematopoietic development in vitro
- 2000
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Ingår i: Journal of Virology. - : American Society for Microbiology. - 0022-538X .- 1098-5514. ; 74:22, s. 84-10778
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Tidskriftsartikel (refereegranskat)abstract
- The murine embryonal stem (ES) cell virus (MESV) can express transgenes from the long terminal repeat (LTR) promoter/enhancer in undifferentiated ES cells, but expression is turned off upon differentiation to embryoid bodies (EBs) and hematopoietic cells in vitro. We examined whether a human immunodeficiency virus type 1-based lentivirus vector pseudotyped with the vesicular stomatitis virus G protein (VSV-G) could transduce ES cells efficiently and express the green fluorescent protein (GFP) transgene from an internal phosphoglycerate kinase (PGK) promoter throughout development to hematopoietic cells in vitro. An oncoretrovirus vector containing the MESV LTR and the GFP gene was used for comparison. Fluorescence-activated cell sorting analysis of transduced CCE ES cells showed 99.8 and 86.7% GPF-expressing ES cells in the VSV-G-pseudotyped lentivirus (multiplicity of infection [MOI] = 59)- and oncoretrovirus (MOI = 590)-transduced cells, respectively. Therefore, VSV-G pseudotyping of lentiviral and oncoretrovirus vectors leads to efficient transduction of ES cells. Lentivirus vector integration was verified in the ES cell colonies by Southern blot analysis. When the transduced ES cells were differentiated in vitro, expression from the oncoretrovirus LTR was severely reduced or extinct in day 6 EBs and ES cell-derived hematopoietic colonies. In contrast, many lentivirus-transduced colonies, expressing the GFP gene in the undifferentiated state, continued to express the transgene throughout in vitro development to EBs at day 6, and many continued to express in cells derived from hematopoietic colonies. This experimental system can be used to analyze lentivirus vector design for optimal expression in hematopoietic cells and for gain-of-function experiments during ES cell development in vitro.
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| 26. |
- Huang, B. T., et al.
(författare)
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Towards Production of gamma-valerolactone via Hydrogenation of Aqueous Levulinic Acid
- 2015
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Ingår i: International Journal of Chemical Reactor Engineering. - : Walter de Gruyter GmbH. - 1542-6580 .- 2194-5748. ; 13:1, s. 119-127
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Tidskriftsartikel (refereegranskat)abstract
- Synthesis of GVL (gamma-valerolactone) via hydrogenation of aqueous LA (levulinic acid) with H-2 over heterogeneous catalyst (Ru/C) was investigated. In the first part, a study of the influence of various operating conditions was conducted including that of temperature (90-180 degrees C), stirring rate (500-1200 rpm), catalyst loading (0.1-2.0 g), hydrogen pressure (0.4-2.8 MPa) and initial LA concentration (0.5-2 M). In the second part, influence of supercritical CO2 (scCO(2)) on hydrogenation rate and GVL yield were investigated. Hydrogenation of aqueous LA under scCO(2) and under N-2 atmosphere was carried out in batch reactor at 150 degrees C and was compared with the case when no additional gases were present. The result indicated that the use of scCO(2) had no beneficial effect neither in terms of LA conversion nor hydrogenation rate when the amount of hydrogen was relatively low compared to the stoichiometry. This effect was mitigated when more hydrogen was present.
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| 27. |
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| 28. |
- Hyvärinen, S, et al.
(författare)
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Towards ionic liquid fractionation of lignocellulosics for fermentable sugars
- 2010
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Ingår i: Cellulose Chemistry and Technology. - 0576-9787. ; 44:4-6, s. 187-195
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Tidskriftsartikel (refereegranskat)abstract
- The present study investigates wood fractionation through ionic liquid (IL) mediated pretreatment, for obtaining simple fermentable sugars, namely oligo- and monosaccharides, and in particular hexoses (andpentoses). The study focuses on softwood, Scots Pine (Pinus sylvestris) and Norway Spruce (Picea abies), exposed to ionic liquid 1-ethyl-3-methylimidazolium chloride (EmimCl). Since both EmimCl and the monosaccharides are water-soluble and dissolve readily in similar solvents, the separation of this hydrophilic IL from sugars is difficult. Moreover, the analytics of monosaccharides released from lignocellulosics with the help of EmimCl is challenging. Sufficiently diluted samples, with low enough EmimCl concentrations, tolerated by GC sugar columns, can be also analyzed by GC. The results obtained suggest that some IL-tolerating HPLC columns can be utilized for a quantitative determination of monosaccharides. However, frequently, these columns have low separation ability for monosaccharides and, consequently, the retention time values are very close to each other. So far, the best results on HPLC utilization were obtained with isocratic elution, using a refractive index detector and a diode array UV detector in series.
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| 29. |
- Hyvärinena, S., et al.
(författare)
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Sugars and sugar derivatives in ionic liquid media obtained from lignocellulosic biomass : comparison of capillary electrophoresis and chromatographic analysis
- 2014
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Ingår i: Catalysis Today. - : Elsevier. - 0920-5861 .- 1873-4308. ; 223, s. 18-24
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Tidskriftsartikel (refereegranskat)abstract
- Processing of woody lignocellulosic biomass, under heating in combination with ionic liquids (ILs) was studied in order to obtain simple (fermentable) sugars. Due to the new environmental challenges, finding greener ways to produce platform chemicals and/or bio-fuels has become a popular research area. Various industrial, pilot or laboratory scale technologies for the depolymerization or fractionation of lignocellulosic polysaccharides to monomers are known. One of the new, interesting, methods is to utilize ILs in biomass pre-treatment procedures with an aim to bypass other pre-treatment methods. Furthermore, in order even to initiate studies whether ILs can contribute to catalytic depolymerization, there has to be a robust way to analyze the IL-treated lignocellulosics. This is a major issue since woody samples that contain any salts such as ILs can indeed be quite challenging from the analytic point of view. The applied capillary electrophoresis was found to be an excellent analytical method providing substantial improvements compared to the earlier used chromatographic methods.In this work it was demonstrated that application of ILs, at elevated temperatures, contributes to hydrolysis and depolymerization of lignocellulose. The effect is time and temperature dependent: in harsh conditions sugars degrade but too low processing temperatures or short treatment times result in no meaningful effect. The formation of the degradation products of the monosaccharides is a good indicator of the harshness of the applied chemical conditions. Evidently, furfural and 5-(hydroxymethyl)furfural formed in rather short treatment times.
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| 30. |
- Joensuu, J, et al.
(författare)
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Maternal childbirth experience and pain relief methods: a retrospective 7-year cohort study of 85 488 parturients in Finland
- 2022
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Ingår i: BMJ open. - : BMJ. - 2044-6055. ; 12:5, s. e061186-
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Tidskriftsartikel (refereegranskat)abstract
- The aim of this study was to analyse the relation between the used labour pain relief and childbirth experience measured by Visual Analogue Scale (VAS).DesignA retrospective cohort study.SettingChildbirth in five Helsinki University Hospital delivery units from 2012 to 2018.Primary outcome measureChildbirth experience measured by VAS and classified in three groups (negative VAS=1–5, positive VAS=6–8 and highly positive=9–10).ResultsThe use of epidural or non-epidural compared with non-medical pain relief methods decreased the likelihood to experience highly positive childbirth for primiparous (adjusted OR (aOR)EPIDURAL=0.64, 95% CI 0.57 to 0.73; and aORNON-EPIDURAL=0.76, 95% CI 0.66 to 0.87) and multiparous (aOREPIDURAL=0.90, 95% CI 0.84 to 0.97 and aORNON-EPIDURAL=0.80, 95% CI 0.74 to 0.86) parturients. The effects of epidural differed between primiparas and multiparas. In multiparas epidural was associated with decreased odds for experiencing negative childbirth compared with the non-medical group (aOR=0.70, 95% CI 0.57 to 0.87), while the effect of epidural was considered insignificant in primiparas (aOR=1.28, 95% CI 0.93 to 1.77).ConclusionWhile the use of medical—epidural and non-epidural—pain relief methods were not associated with odds for experiencing negative childbirth in primiparas, using epidural helps to avoid negative experience in multiparas. However, the odds for experiencing highly positive childbirth were decreased if the parturients used any medical pain relief for both primiparas and multiparas. Consequently, the effect of pain relief on the childbirth experience is strongly confounded by indication. Thus, the use of pain relief per se plays a limited role in the complex formation of the overall childbirth experience.
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| 31. |
- Joensuu, J, et al.
(författare)
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Maternal childbirth experience and time of delivery: a retrospective 7-year cohort study of 105 847 parturients in Finland
- 2021
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Ingår i: BMJ open. - : BMJ. - 2044-6055. ; 11:6, s. e046433-
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Tidskriftsartikel (refereegranskat)abstract
- To explore how the time of delivery influences childbirth experience.DesignA retrospective cohort study.SettingChildbirth in the four Helsinki and Uusimaa Hospital District hospitals, Finland, from 2012 to 2018.Participants105 847 childbirths with a singleton live fetus.Main outcome measuresChildbirth experience measured by Visual Analogue Scale (VAS).ResultsThe major difference in average childbirth experience measured by VAS was between primiparas (8.03; 95% CI 8.01 to 8.04) and multiparas (8.47; 95% CI 8.45 to 8.48). Risk ratio (RR) of the low VAS (≤5) was 2.3 when primiparas were compared with multiparas. Differences in VAS between distinct periods were found in two stages: annual and time of day. The decrease in VAS from 2012–2016 to 2017–2018 in primiparas was from 7.97 (95% CI 7.95 to 7.99) to 7.80 (95% CI 7.77 to 7.83) and from 2014–2016 to 2017–2018 in multiparas from 8.60 (95% CI 8.58 to 8.61) to 8.49 (95% CI 8.47 to 8.52). Corresponding RRs of low VAS were 1.3 for primiparas and 1.2 for multiparas. Hourly differences in VAS were detected in primiparas between office hours 08:00–15:59 (7.97; 95% CI 7.94 to 7.99) and other times (night 00:00–07:59; 7.91; 95% CI 7.88 to 7.94; and evening 16:00–23:59; 7.90; 95% CI 7.87 to 7.92). In multiparas differences in VAS were detected between evening (8.52; 95% CI 8.50 to 8.54) and other periods (night; 8.56; 95% CI 8.54 to 9.58; and office hours; 8.57; 95% CI 8.55 to 8.59).ConclusionThe maternal childbirth experience depended on the time of delivery. Giving birth during the evening led to impaired childbirth experience in both primiparas and multiparas, compared with delivery at other times. The impact of labour induction on childbirth experience should be further examined. The reorganisation of delivery services and the reduction of birth preparations might affect annual VAS. VAS is a simple method of measuring the complex entity of childbirth experience, and our results indicate its ability to capture temporal variation.
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| 32. |
- Kirilin, A, et al.
(författare)
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Mechanistic investigations of the reaction network in chemobiocatalyzed synthesis of R1Phenylethyl Acetate
- 2010
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Ingår i: Kinetics and catalysis. - : Springer. - 0023-1584 .- 1608-3210. ; 51:6, s. 809-815
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Tidskriftsartikel (refereegranskat)abstract
- The kinetics and reaction network of the onepot synthesis of R1phenylethyl acetate was investigated at 70°C in toluene over a combination of three different catalysts: PdZn/Al2O3 as a catalyst for acetophenone hydrogenation, lipase as an enzymatic catalyst for R1phenylethanol acylation with ethyl acetate and Ru/Al2O3 as a racemization catalyst for S1phenylethanol. In addition to the desired reactions, other reactions, namely hydrogenolysis and dehydration of (R, S)1phenylethanol and debenzylation of (R, S)1phenylethyl acetate also occurred. The kinetic results revealed that ethylbenzene formation was enhancedwith higher amounts of PdZn/Al2O3, whereas lipase did not catalyze ethylbenzene formation. Furthermore, ethylbenzene was formed in the hydrogenolysis of (R, S)phenylethanol and in the debenzylation of (R, S)1phenylethylacetate over Pd/Al2O3 catalyst. The presence of Ru/Al2O3 catalyst, in which Ru was in the oxidation state of 3+, enhanced the formation of R1phenylethyl acetate, although no clear racemization of S1phenylethanol during the onepot synthesis of R1phenylethyl acetate was observed. Dynamic kinetic resolution of (R, S)1phenylethanol in toluene, was, however, demonstrated over Ru/Al2O3 and lipase.
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| 33. |
- Koffert, J. P., et al.
(författare)
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Metformin treatment significantly enhances intestinal glucose uptake in patients with type 2 diabetes: Results from a randomized clinical trial
- 2017
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Ingår i: Diabetes Research and Clinical Practice. - : Elsevier BV. - 0168-8227 .- 1872-8227. ; 131, s. 208-216
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Tidskriftsartikel (refereegranskat)abstract
- Aims Metformin therapy is associated with diffuse intestinal 18F-fluoro-deoxyglucose (FDG) accumulation in clinical diagnostics using routine FDG-PET imaging. We aimed to study whether metformin induced glucose uptake in intestine is associated with the improved glycaemic control in patients with type 2 diabetes. Therefore, we compared the effects of metformin and rosiglitazone on intestinal glucose metabolism in patients with type 2 diabetes in a randomized placebo controlled clinical trial, and further, to understand the underlying mechanism, evaluated the effect of metformin in rats. Methods Forty-one patients with newly diagnosed type 2 diabetes were randomized to metformin (1g, b.i.d), rosiglitazone (4mg, b.i.d), or placebo in a 26-week double-blind trial. Tissue specific intestinal glucose uptake was measured before and after the treatment period using FDG-PET during euglycemic hyperinsulinemia. In addition, rats were treated with metformin or vehicle for 12weeks, and intestinal FDG uptake was measured in vivo and with autoradiography. Results Glucose uptake increased 2-fold in the small intestine and 3-fold in the colon for the metformin group and associated with improved glycemic control. Rosiglitazone increased only slightly intestinal glucose uptake. In rodents, metformin treatment enhanced intestinal FDG retention (P=0.002), which was localized in the mucosal enterocytes of the small intestine. Conclusions Metformin treatment significantly enhances intestinal glucose uptake from the circulation of patients with type 2 diabetes. This intestine-specific effect is associated with improved glycemic control and localized to mucosal layer. These human findings demonstrate directs effect of metformin on intestinal metabolism and elucidate the actions of metformin. Clinical trial number NCT02526615 © 2017 The Authors
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| 34. |
- Kontturi, V, et al.
(författare)
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Simultaneous detection of absorption spectrum and refractive index ratio with a spectrophotometer : monitoring contaminants in bioethanol
- 2011
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Ingår i: Measurement science and technology. - : IOP Publishing. - 0957-0233 .- 1361-6501. ; 22:5, s. 6-
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Tidskriftsartikel (refereegranskat)abstract
- The optical properties of a biofuel resulting from the fungi-treated lignocellulosic biomass in an ethanol matrix were studied. The matrix simulates the case that the bioethanol is contaminated by sugars, water and colour pigments that reduce the quality of the biofuel and compromise the combustion process. It is suggested that by applying a spectrophotometer only, it is possible to obtain valid information, i.e. the spectral features of the contaminants as well as the refractive index ratio of bioethanol. This allows for simultaneous purity and density detection of biomass-derived liquids or liquid biofuels, in comparison to a reference representing an ideal bioethanol (pure ethyl alcohol, ethanol of 99.5% purity (v/v)).
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| 35. |
- Konwar, Lakhya Jyoti, 1987-, et al.
(författare)
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Sidestreams from bioenergy and biorefinery complexes as a resource for circular bioeconomy
- 2018. - 1
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Ingår i: Waste biorefinery. - Amsterdam : Elsevier. - 9780444639929 ; , s. 85-125
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Bokkapitel (refereegranskat)abstract
- One of the main drivers for the establishment of biorefineries and the drive toward bioeconomy is the call for sustainability. However, the modern-day biorefinery must embrace on the concept of whole-crop approach with complete feedstock utilization and zero waste, leading to a portfolio of valuable products in which food, feed, fuels, chemicals, and materials are produced. In this chapter, we address upon the prospective of improving the economics and carbon efficiency of existing bioenergy and biorefinery complexes through a circular bioeconomy-based whole-crop utilization. We emphasize hereupon the possibility to coproduce value-added products (e.g., chemicals, materials, or energy) from the various sidestreams or by-products generated from biorefinery operations such as CO2, glycerol, hemicelluloses, lignin, and extractives together with their potential as a raw material or chemical platform for the production of marketable products using available process technologies.
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| 36. |
- Kordas, Krisztian, et al.
(författare)
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On the Interaction of Metal Nanoparticles with Supports
- 2015
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Ingår i: Topics in catalysis. - : Springer Science+Business Media B.V.. - 1022-5528 .- 1572-9028. ; 58:14-17, s. 1127-1135
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Tidskriftsartikel (refereegranskat)abstract
- Metal nanoparticles supported on surfaces often undergo sintering even at moderate temperatures. The degree of sintering is typically influenced by the surface chemistry indicating that besides the commonly believed Ostwald ripening also other processes associated with metal surface diffusion are responsible for the nanoparticle size growth. In addition to the deterioration in metal dispersion, carbon supports can show chemical instability leading to their partial degradation in the proximity of the nanoparticles both in reducing and oxidizing environments at elevated temperatures. This work reports a study of Pd, Pt and Ni nanoparticles anchored on carbon (activated carbon, graphite and carbon nanotubes) as well as titania (nanoparticles and microparticles) surfaces frequently applied as catalyst materials in heterogeneous catalysis and photocatalysis, and evaluate the potential events causing metal sintering and degradation of the supports using transmission electron microscopy analysis.
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| 37. |
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| 38. |
- Lê, A D, et al.
(författare)
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Neurobiological processes in alcohol addiction.
- 2001
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Ingår i: Alcoholism, clinical and experimental research. - 0145-6008. ; 25:5 Suppl ISBRA
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Forskningsöversikt (refereegranskat)abstract
- This article represents the proceedings of a symposium at the ISBRA Meeting in Yokohama, Japan. The chairs were A. D. Lê and K. Kiianmaa. The presentations were (1) Alcohol reward and aversion, by C. L. Cunningham; (2) The role of sensitization of neuronal mechanisms in ethanol self-administration, by J. A. Engel, M. Ericson, and B. Söderpalm; (3) Alcohol self-administration in dependent animals: Neurobiological mechanisms, by G. F. Koob, A. J. Roberts, and F. Weiss; (4) Stress and relapse to alcohol, by A. D. Lê; (5) Alcohol-preferring AA and alcohol-avoiding ANA rats differ in locomotor activation induced by repeated morphine injections, by P. Hyytiä, S. Janhunen, J. Mikkola, P. Bäckström, and K. Kiianmaa; and (6) Initial sensitivity and acute functional tolerance to the hypnotic effects of ethanol in mice genetically selected for mild and severe ethanol withdrawal convulsions, by I. Ponomarev and J. C. Crabbe.
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| 39. |
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| 40. |
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| 41. |
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| 42. |
- Mohl, Melinda, et al.
(författare)
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Titania nanofibers in gypsum composites : an antibacterial and cytotoxicology study
- 2014
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Ingår i: Journal of Material Chemistry B. - : Royal Society of Chemistry. - 2050-750X .- 2050-7518. ; 2:10, s. 1307-1316
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Tidskriftsartikel (refereegranskat)abstract
- Further developments of antibacterial coatings based on photocatalytic nanomaterials could be a promising route towards potential environmentally friendly applications in households, public buildings and health care facilities. Hereby we describe a simple chemical approach to synthesize photocatalytic nanomaterial-embedded coatings using gypsum as a binder. Various types of TiO2 nanofiber-based photocatalytic materials (nitrogen-doped and/or palladium nanoparticle decorated) and their composites with gypsum were characterized by means of scanning (SEM) and transmission (TEM) electron microscopy as well as electron and X-ray diffraction (XRD) and energy-dispersive X-ray spectroscopy (EDX) techniques. These gypsum-based composites can be directly applied as commercially available paints on indoor walls. Herein we report that surfaces coated with photocatalytic composites exhibit excellent antimicrobial properties by killing both methicillin-sensitive Staphylococcus aureus (MSSA) and methicillin-resistant Staphylococcus aureus (MRSA) under blue light. In the case of MSSA cells, the palladium nanoparticle-decorated and nitrogen-doped TiO2 composites demonstrated the highest antimicrobial activity. For the MRSA strain even pure gypsum samples were proven to be efficient in eradicating Gram-positive human pathogens. The cytotoxicity of freestanding TiO2 nanofibers was revealed by analyzing the viability of HeLa cells using MTT and fluorescent cell assays.
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| 43. |
- Nakano, H., et al.
(författare)
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Haemogenic endocardium contributes to transient definitive haematopoiesis
- 2013
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Ingår i: Nature Communications. - : Springer Science and Business Media LLC. - 2041-1723 .- 2041-1723. ; 4
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Tidskriftsartikel (refereegranskat)abstract
- Haematopoietic cells arise from spatiotemporally restricted domains in the developing embryo. Although studies of non-mammalian animal and in vitro embryonic stem cell models suggest a close relationship among cardiac, endocardial and haematopoietic lineages, it remains unknown whether the mammalian heart tube serves as a haemogenic organ akin to the dorsal aorta. Here we examine the haemogenic activity of the developing endocardium. Mouse heart explants generate myeloid and erythroid colonies in the absence of circulation. Haemogenic activity arises from a subset of endocardial cells in the outflow cushion and atria earlier than in the aorta-gonad-mesonephros region, and is transient and definitive in nature. Interestingly, key cardiac transcription factors, Nkx2-5 and Isl1, are expressed in and required for the haemogenic population of the endocardium. Together, these data suggest that a subset of endocardial/endothelial cells serve as a de novo source for transient definitive haematopoietic progenitors. © 2013 Macmillan Publishers Limited. All rights reserved.
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| 44. |
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| 45. |
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| 46. |
- Pezoa, R., et al.
(författare)
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Use of ionic liquids in the pretreatment of forest and agricultural residues for the production of bioethanol
- 2010
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Ingår i: Cellulose Chemistry and Technology. - : Publishing House of the Romanian Academy. - 0576-9787. ; 44:4-6, s. 165-172
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Tidskriftsartikel (refereegranskat)abstract
- Pretreatment of lignocellulosic materials is an important step to achieve higher amounts of simple sugars, mono- and disaccharides, for obtaining ethanol as a biofuel, via enzymatic hydrolysis. The study introduces a concept that utilizes ionic liquids (ILs) as solvents in the pretreatment step, before enzymatic saccharification, for both forest residues (Eucalyptus (Eucalyptus globulus Labill.) and Lenga (Nothofagus pumilio (POEPP. EX. ENDL.) KRASSER) and for agricultural residues (wheat and corn). The procedure was evaluated at four different temperatures (80, 121, 150 and 170 °C) for 30 and 60 min, respectively, with 1-ethyl-3-methylimidazolium chloride ([EMIM+][Cl-]). Subsequent enzymatic hydrolysis of these materials was carried out at 47 °C, for 72 h, with commercial cellulases. The results demonstrated that the best experimental conditions found for wheat, corn and Eucalyptus residues were the following: 150 °C, for 60 min, yielding a total of 46, 48 and 30% sugars, respectively; in the case of Lenga residues, the optimum conditions were: 150 °C for 30 min, yielding a total of 40% sugars after saccharification. Temperatures exceeding 170 °C are not recommended for this type of pretreatment with [EMIM+][Cl-], because significant portions of cellulose could be dissolved in this IL. Finally, an analysis of the solid material after ionic liquid pretreatment is required, to determine the changes related to lignin, cellulose and hemicellulose composition.
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| 47. |
- Privalova, Elena, et al.
(författare)
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CO2 capture from biogas : absorbent selection
- 2013
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Ingår i: RSC Advances. - : RSC Publishing. - 2046-2069. ; 3:9, s. 2979-2994
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Tidskriftsartikel (refereegranskat)abstract
- The development of proper biogas upgrading technology offers a viable means to utilize biogas in conventional power systems. In this paper, various molecular and ionic solvent systems were evaluated for CO2 removal from biogas in a loop reactor system. The performance of amine solutions, ionic liquids and their mixtures, amino acid salts and solutions blended with piperazine was compared in terms of their CO2 loading capacity. The experimental results revealed that addition of small amounts of piperazine can increase the efficiency of abovementioned solutions on average by 30 vol%. The CO2 capturing capacity of the most promising solvents was in the range of 50-60 L CO2/L absorbent. The regeneration of the solvent mixtures can be challenging since the solvents could loose 16-43 vol% of their initial efficiency upon CO2 release. Ionic liquid [C4mim][acetate] was found to be an efficient VOCs scrubbing media. Moreover, upon use of this ionic liquid, the amount of identified volatile organic compounds (VOCs) in the studied samples was reduced by 65 wt%, while the use of 15 wt% aqueous N-methyldiethanolamine (MDEA) resulted only in 32 wt% reduction in the amount of VOCs.
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| 48. |
- Privalova, E, et al.
(författare)
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CO2 removal with ‘switchable’ versus ‘classical’ ionic liquids
- 2012
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Ingår i: Separation and Purification Technology. - Amsterdam : Elsevier. - 1383-5866 .- 1873-3794. ; 97, s. 42-50
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Tidskriftsartikel (refereegranskat)abstract
- Switchable ionic liquids (SILs) are promising solvents for CO2 separation due to their high CO2 capturing efficiency and easy preparation compared to ‘classical’ ionic liquids. Considering viscosity, the present study has demonstrated that SILs formed at least two times stronger chemical bonds with CO2 than studied classical ionic liquids (ILs). Furthermore, the reversible properties of SILs were confirmed by evaluation of different regeneration methods. On average, molar fractions of CO2 were more than 0.3 outperforming acetate-based ILs (molar fraction of CO2 around 0.25) and more than ten times the capacity of physical ionic liquids (molar fraction 0.02). Consequently, SILs are found to be efficient CO2 absorbents operating at atmospheric pressure.HighlightsComparison of ionic liquid systems acting as chemical vs. physical solvents in practical terms. ► Recycling and reuse issues of ionic liquids in carbon dioxide capture. ► Introduction of new types of switchable ionic liquids. ► Studying the capture-release cycle behavior of the aforementioned ionic liquids. ► In essence, we have focused on engineering aspects.
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| 49. |
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| 50. |
- Privalova, E, et al.
(författare)
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Ionic liquids versus amine solutions in biogas upgrading : the level of volatile organic compounds
- 2013
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Ingår i: Biofuels. - : future science ltd. - 1759-7269 .- 1759-7277. ; 4:3, s. 295-311
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Tidskriftsartikel (refereegranskat)abstract
- Background: This article provides information related to the occurrence of volatile organic compounds before and after biogas purification, by means of both aqueous amine solutions and ionic liquids. Results & discussion: Encouraging results were obtained. Under the experimental conditions, 1-butyl-3-methylimidazolium acetate ionic liquid appeared to perform at least two-times better than aqueous amines solutions, since it captured 65 wt% of the identified volatile organic compounds, while aqueous amine solutions retained around 35 wt% only. However, in the case of octamethylcyclotetrasiloxane and dichlorobenzene, aqueous amine solutions rendered better purification performance and diminished the concentration of aforementioned compounds by a factor of five and ten, respectively. Conclusion: This paper sheds new light on ionic liquids as potential separation sorbents and contributes to the understanding of the complex science of biogas upgrading and utilization of renewable energy resources.
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