| 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. |
- 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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| 3. |
- Kukkola, J, et al.
(författare)
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Novel printed nanostructured gas sensors
- 2011
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Ingår i: Procedia Engineering. - : Elsevier. - 1877-7058. ; 25, s. 896-899
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Tidskriftsartikel (refereegranskat)abstract
- There is a need for low-cost mass-production circuits on various substrates, possibly performing some simple functions as switches, antennas, displays, and sensors. Also in the field of gas sensors widely used in several applications there is a need for such novel fabrication technologies and materials. In this paper, we present three gas sensor structures fabricated using novel printing techniques. Inkjet and gravure printing techniques were used for fabrication of resistive WO3 nanoparticle gas sensors for detection of NO, and inkjet printing was utilized for fabrication of solid electrolyte (mixture of H3PW12O40 and PVC) in a nanostructured Metal-Electrolyte-Insulator- Semiconductor (MEIS) transistor for detection of H2. The sensor structures were found to be sensitive for detection of NO below 10 ppm, and H2 below 100 ppm concentrations in synthetic air, respectively.
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| 4. |
- 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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| 5. |
- 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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| 6. |
- 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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| 7. |
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| 8. |
- Hajek, J., et al.
(författare)
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Processing of gluconic acid derivatives to value added monosaccharides via oxidative degradation
- 2012
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Konferensbidrag (refereegranskat)abstract
- One of the components that can be efficiently obtained, e.g., via fermentation of polysaccharide containing waste or biomass, is glucose and some of its derivatives. Degradation of C6 carbohydrates yields corresponding C5 sugars. In case of gluconic acid, the product is arabinose. The reaction, illustrating a valuable synthetic route, e.g., for the abatement of waste streams containing gluconic acid is shown. In spite of high yields, the reaction is characterized by complex analytics due to the presence of organic as well as inorganic by-products. Under optimized conditions, yields between 70-80% could be achieved. This is an abstract of a paper presented at the CHISA 2012 - 20th International Congress of Chemical and Process Engineering and PRES 2012 - 15th Conference PRES (Prague, Czech Republic 8/25-29/2012).
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| 9. |
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| 10. |
- Huerta, I., et al.
(författare)
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Effect of low hydrogen to palladium molar ratios in the direct synthesis of H2O2 in water in a trickle bed reactor
- 2015
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Ingår i: Catalysis Today. - : Elsevier BV. - 0920-5861 .- 1873-4308. ; 248, s. 91-100
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Tidskriftsartikel (refereegranskat)abstract
- Application of a trickle bed reactor (TBR) renders a very compact solution to carry out direct synthesis of hydrogen peroxide in water over a carbon supported palladium. The laboratory scale reactor was filled with silica particles (50-70 mesh) physically mixed with 37.5 to 75 mg of 5%Pd/C particles. The reaction conditions applied were 15 degrees C, 15-28 barg, 0.5 to 6 mL min(-1) of liquid and 4.0-4.5 mL min(-1) of gas flowrate (86.7/11/2.23 mol% of CO2/O-2/H-2). Thus, we demonstrated that the ratio between H-2 and Pd is one of the key factors to achieve optimized, higher yields of hydrogen peroxide. Consequently, low H-2 concentrations lead to low productivities. One of the least studied parameters, addressed here, is the ratio between the bed filling (SiO2) and the catalyst; i.e. the active catalytic species dilution effect. In short, it was found that when the amount of Pd was reduced below 0.094 mg Pd cm(-3) SiO2 the highest productivity of H2O2 could be achieved. The selectivity obtained were between 5.3 and 38.0%, respectively, corresponding to turn-over-frequencies (TOF) ranging from 65 to 921 mmol H2O2 gPd(-1) h(-1). (C) 2014 Elsevier B.V. All rights reserved.
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| 11. |
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| 12. |
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| 13. |
- 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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| 14. |
- 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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| 15. |
- 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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| 16. |
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| 17. |
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| 18. |
- Anugwom, Ikenna, et al.
(författare)
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In quest for the optimal delignification of lignocellulosic biomass using hydrated, SO2 switched DBU MEASIL switchable ionic liquid
- 2016
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Ingår i: Chemical Engineering Journal. - : Elsevier. - 1385-8947 .- 1873-3212. ; 297, s. 256-264
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Tidskriftsartikel (refereegranskat)abstract
- In this paper, various process parameters aiming at optimal short-time-high-temperature (STHT) process were studied upon fractionation of Nordic woody biomass into its primary constituents. Highly diluted, aqueous 'SO2-switched' switchable ionic liquid (SIL) based on an alkanol amine (monoethanol amine, MEA) and an organic superbase (1,8-diazabicyclo-[5.4.0]-undec-7-ene, DBU) was applied. The ultimate goal was to develop a more sustainable, environmentally friendly and cost efficient systems for efficient separation of the lignocellulosic fractions. One of the main products from the SIL fractionation is cellulose-rich pulp with very low lignin content, complemented with hemicelluloses. The NMR results reveal that substantial removal of lignin occurs even when relatively low amount of SIL was used. Further, a simple mathematical model describing the dissolution of the lignocellulose components (hemicellulose and lignin) and weight loss of wood as a function of time is described. Moreover, the most efficient process involved the use of SpinChem (R) rotating bed reactor while upon use of a flow through (loop) reactor, promising results were obtained at a treatment time of 4 h. Still, all the reactor systems studied gave rise to a rather low removal of hemicelluloses which mean that the solvent system is primary selective towards lignin dissolution.
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| 19. |
- Asres, Georgies Alene, et al.
(författare)
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Ultrasensitive H2S gas sensors based on p-type WS2 hybrid materials
- 2018
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Ingår i: Nano Reseach. - : Springer. - 1998-0124 .- 1998-0000. ; 11:8, s. 4215-4224
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Tidskriftsartikel (refereegranskat)abstract
- Owing to their higher intrinsic electrical conductivity and chemical stability with respect to their oxide counterparts, nanostructured metal sulfides are expected to revive materials for resistive chemical sensor applications. Herein, we explore the gas sensing behavior of WS2 nanowire-nanoflake hybrid materials and demonstrate their excellent sensitivity (0.043 ppm-1) as well as high selectivity towards H2S relative to CO, NH3, H2, and NO (with corresponding sensitivities of 0.002, 0.0074, 0.0002, and 0.0046 ppm-1, respectively). Gas response measurements, complemented with the results of X-ray photoelectron spectroscopy analysis and first-principles calculations based on density functional theory, suggest that the intrinsic electronic properties of pristine WS2 alone are not sufficient to explain the observed high sensitivity towards H2S. A major role in this behavior is also played by O doping in the S sites of the WS2 lattice. The results of the present study open up new avenues for the use of transition metal disulfide nanomaterials as effective alternatives to metal oxides in future applications for industrial process control, security, and health and environmental safety.
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| 20. |
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| 21. |
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| 22. |
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| 23. |
- García-Serna, Juan, et al.
(författare)
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Engineering in direct synthesis of hydrogen peroxide : targets, reactors and guidelines for operational conditions
- 2014
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Ingår i: Green Chemistry. - : Royal Society of Chemistry. - 1463-9262 .- 1463-9270. ; 16:5, s. 2320-2343
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Tidskriftsartikel (refereegranskat)abstract
- The demand for hydrogen peroxide is booming since it is considered as one of the most environmentally friendly and versatile chemical oxidants available and with a wide range of applications. The annual market close to 3000 kt/y being produced via the auto-oxidation process (with 2-ethyl anthraquinone (traditional) or amyl anthraquinone for mega-plants) is mostly supplied by the company Solvay (30%), followed by Evonik (20%) and Arkema (13%) as key intermediate. Nevertheless, the dream of direct synthesis process is close to a century year-old and it has gained momentum in research effort during the last decade with more than 15 groups active in the world. In this review, we focus the discussion on the targets, e.g. plant tonnage, the reactors and the most feasible industrial operational conditions, based on our experience, and from the point of view using the chemical engineering tools available. Thus, direct synthesis can be competitive when on-site production is required and capacities less than 10 kt/y are demanded. The total investment cost should be approximately in between 40.3±12.1 MM$ (in 2012) for a 10 kt/y size process to be comparable to the traditional process in terms of costs. Moreover, all kinds of reactors used are hereby discussed emphasizing the pros and cons; the most common ones are batch and semicontinous modes of operations. However, at the moment, demonstrations of continuous operations as well as carefully determined kinetics are needed in order to scale up the process. Finally, operational conditions, including the catalyst composition (active metal, oxidation state and support), promoters (halides and acids-pH-isoelectric point), solvents, pressure and temperature need to be carefully analysed. In our opinion, as we try to show here, H2O2 direct synthesis is a competitive process and ready for larger scale demonstration. Also, more than a hundred patents within the area support this claim, although the barries of technology demonstration and further licensing are still pending.
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| 24. |
- Golets, Mikhail, 1987-, et al.
(författare)
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A kinetic study of the liquid phase acetoxylation of α-pinene
- 2012
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Ingår i: Topics in catalysis. - : Springer. - 1022-5528 .- 1572-9028. ; 55:7-10, s. 649-656
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Tidskriftsartikel (refereegranskat)abstract
- The present study introduces kinetic modeling of liquid phase α-pinene acetoxylation with acetic acid over an ion-exchange resin catalyst. The reaction was carried out in a laboratory scale high-pressure autoclave. α-terpinyl (35 wt%) and bornyl (40 wt%) acetates were the primary products. The predominant reaction pathways were identified and evaluated.
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| 25. |
- Golets, Mikhail, 1987-, et al.
(författare)
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Liquid phase acetoxylation of α-pinene
- 2012
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Ingår i: NWBC 2012. - : VTT. - 9789513878801 - 9789513878818 ; , s. 339-341
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Konferensbidrag (refereegranskat)abstract
- Chemical pulping and bio-refining results in many fractions such as. tall oil and turpentine that contain substantial amounts of α-pinene and other terpenes. Today these fractions are usually burned in the recovery boilers. However, the northern forest industry, primarily utilizing the boreal forests, faces serious challenges from developing markets (South America, Asia), because of lower cost of raw material resources and labor. At the same time, there is a growing concern about emissions of greenhouse gases and security of supply connected to the use of fossil oil for transportation and as a feedstock for the chemical industry. The mentioned fact renders the substitution of petrochemical-related raw materials an important field of research.The flavor and fragrance industry is one of the main users of terpene esters. From those esters, α-terpinyl and bornyl acetates are produced from α-pinene and commonly used for bath products and perfumes. Due to the imperfection of conventional two-stage production method of the mentioned esters, which lays in the equipment corrosion, environmental pollution, large load and nonrecyclability of a catalyst, the novel one-stage catalytic process is always of high priority.The possibility of α-pinene liquid phase catalytic acetoxylation is introduced in the present study. The complex product distribution and reaction network analysis, influent reaction and catalytic factors optimization, combined with the reaction kinetic modeling were the main aims of research. The ion-exchange resin catalyst Amberlyst 70 was characterized as the catalyst used in the studied reaction and compared with the solvent-catalyzed mode. Valuable combinations of acetates were obtained for both studied modes. A wide range of process factors were studied in the batch (Parr) reactor used. The mentioned type of reactor is suitable for the consequent industrial operations scale-up calculations.
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| 26. |
- 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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| 27. |
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| 28. |
- Haapanen, Markus J., et al.
(författare)
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Early growth, stress, and socioeconomic factors as predictors of the rate of multimorbidity accumulation across the life course : a longitudinal birth cohort study
- 2024
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Ingår i: Lancet healthy longevity. - 2666-7568. ; 5:1, s. e56-e65
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Tidskriftsartikel (refereegranskat)abstract
- Background: Early growth, stress, and socioeconomic factors are associated with future risk of individual chronic diseases. It is uncertain whether they also affect the rate of multimorbidity accumulation later in life. This study aimed to explore whether early life factors are associated with the rate at which chronic diseases are accumulated across older age.Methods: In this national birth cohort study, we studied people born at Helsinki University Central Hospital, Helsinki, Finland between Jan 1, 1934, and Dec 31, 1944, who attended child welfare clinics in the city, and were living in Finland in 1971. Individuals who had died or emigrated from Finland before 1987 were excluded, alongside participants without any registry data and who died before the end of the registry follow-up on Dec 31, 2017. Early anthropometry, growth, wartime parental separation, and socioeconomic factors were recorded from birth, child welfare clinic, or school health-care records, and Finnish National Archives. International Classification of Diseases codes of diagnoses for chronic diseases were obtained from the Care Register for Health Care starting from 1987 (when participants were aged 42-53 years) until 2017. Linear mixed models were used to study the association between early-life factors and the rate of change in the number of chronic diseases over 10-year periods.Findings: From Jan 1, 1934, to Dec 31, 2017, 11 689 people (6064 [51 center dot 9%] men and 5625 [48 center dot 1%] women) were included in the study. Individuals born to mothers younger than 25 years (beta 0 center dot 09; 95% CI 0 center dot 06-0 center dot 12), mothers with a BMI of 25-30 kg/m2 (0 center dot 08; 0 center dot 05-0 center dot 10), and mothers with a BMI more than 30 kg/m2 (0 center dot 26; 0 center dot 21-0 center dot 31) in late pregnancy accumulated chronic diseases faster than those born to older mothers (25-30 years) and those with a BMI of less than 25 kg/m2. Individuals with a birthweight less than 2 center dot 5 kg (0 center dot 17; 0 center dot 10-0 center dot 25) and those with a rapid growth in height and weight from birth until age 11 years accumulated chronic diseases faster during their life course. Additionally, paternal occupational class (manual workers vs upper-middle class 0 center dot 27; 0 center dot 23-0 center dot 30) and wartime parental separation (0 center dot 24; 0 center dot 19-0 center dot 29 for boys; 0 center dot 31; 0 center dot 25-0 center dot 36 for girls) were associated with a faster rate of chronic disease accumulation. Interpretation Our findings suggest that the foundation for accumulating chronic diseases is established early in life. Early interventions might be needed for vulnerable populations, including war evacuee children and children with lower socioeconomic status.
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| 29. |
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| 30. |
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| 31. |
- Horacek, J., et al.
(författare)
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Lignin transformations to chemicals
- 2013
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Ingår i: Proceedings of the 1st INTERNATIONAL CONFERENCE ON CHEMICAL TECHNOLOGY. - : Czech Chemical Society. - 9788086238555 ; , s. 382-388
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Konferensbidrag (refereegranskat)abstract
- Sodium lignosulfonate was decomposed at 320 degrees C and 130 bar over various catalysts. Zeolites Beta modified with 0.5 % of Pt showed important effect of Al content in the support on product yields. Alumina-supported NiO was also found as active in lignosulfonate decomposition to guaiacol: Moreover, the contact time of substrate with the active centers was identified as the key reaction factor in lignosulfonate decomposition. Model compounds of lignin decomposition were hydrodeoxygenated at 180 degrees C and 5 MPa over Pt modified zeolites Beta. Dealuminated zeolite was found as more active in phenol conversion than zeolite with similar Si/Al ratio obtained by direct synthesis. Reactivity of cresols increased in order m>o>p for catalyst with higher Si/Al ratio, decrease of Al content resulted in lower reactivity of cresols and change of reactivity order of isomers to o>m>p.
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| 32. |
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| 33. |
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| 34. |
- 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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| 35. |
- 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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| 36. |
- Kirilin, Alexey V., et al.
(författare)
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Aqueous-phase reforming of xylitol over Pt/C and Pt/TiC-CDC catalysts : catalyst characterization and catalytic performance
- 2014
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Ingår i: Catalysis Science & Technology. - : RSC Publishing. - 2044-4753. ; 4:2, s. 387-401
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Tidskriftsartikel (refereegranskat)abstract
- The aqueous phase reforming (APR) of xylitol was studied over five Pt/C catalysts. The correlation between physico-chemical properties of the catalysts and catalytic performance was established. The Pt/C catalysts have different textural properties as well as different mean Pt cluster sizes and surface acidity. The average Pt cluster size was investigated by means of CO chemisorption as well as by TEM. The reaction was found to be structure sensitive and TOF linearly increases with increasing average Pt cluster size in the studied domain. The catalysts which possess higher surface acidity favoured higher rates of hydrocarbon production. On the contrary the Pt/C materials with lower acidities generated hydrogen with high selectivity and TOF.
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| 37. |
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| 38. |
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| 39. |
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| 40. |
- Mikkola, Daniel, et al.
(författare)
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New stellar velocity substructures from Gaia DR3 proper motions
- 2023
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Ingår i: Monthly Notices of the Royal Astronomical Society. - : Oxford University Press (OUP). - 0035-8711 .- 1365-2966. ; 519:2, s. 1989-2003
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Tidskriftsartikel (refereegranskat)abstract
- Local stellar motions are expected, and have been shown, to include signatures of the Galaxy’s past dynamical evolution. These are typically divided into the disc, which shows the dynamical effects of spiral arms and the bar, and the stellar halo, with structures thought to be debris from past mergers. We use Gaia Data Release 3 to select large samples of these populations without limiting them to sources with radial velocities. We apply a penalized maximum likelihood method to these samples to determine the full 3D velocity distribution in Cartesian (U, V, and W) or spherical (vr, vφ, and vθ) coordinates. We find that the disc population is dominated by four moving groups and also detect a new moving group at (U, V) = (−10, −15) km s−1 which we call MMH-0. For the stellar halo, we isolate the accreted component with cuts in transverse velocity and the colour–magnitude diagram. In this component, we find several known structures believed to be caused by past mergers, particularly one around (vr, vφ, vθ) = (−150, −300, and −100) km s−1 appears more prominent than previously claimed. Furthermore, we also identify two new structures near (vr, vφ, and vθ) = (225, 25, and 325) km s−1 and (0, 150, and −125) km s−1, which we refer to as MMH-1 and MMH-2, respectively. These results give new insights into local stellar motions and shows the potential of using samples that are not limited to stars with measured line-of-sight velocities, which is key to providing large samples of stars, necessary for future studies.
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| 41. |
- Mikkola, Daniel, et al.
(författare)
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Radial migration and vertical action in N-body simulations
- 2020
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Ingår i: Monthly Notices of the Royal Astronomical Society. - : Oxford University Press (OUP). - 0035-8711 .- 1365-2966. ; 495:3, s. 3295-3306
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Tidskriftsartikel (refereegranskat)abstract
- We study the radial migration of stars as a function of orbital action as well as the structural properties of a large suite of N-body simulations of isolated disc galaxies. Our goal is to establish a relationship between the radial migration efficiency of stars and their vertical action. We aim to describe how that relationship depends on the relative gravitational dominance between the disc and the dark matter halo. By changing the mass ratio of our disc and dark matter halo, we find a relationship between disc dominance, number, and strength of spiral arms, and the ensuing radial migration as a function of the vertical action. We conclude that the importance of migration at large vertical action depends on the strength of the spiral arms and therefore the dominance of the disc. Populations with more radial action undergo less radial migration, independently of disc dominance. Our results are important for the future of analytical modelling of radial migration in galaxies and further the understanding of radial migration that is a key component of the restructuring of galaxies, including the Milky Way.
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| 42. |
- Mikkola, Daniel, et al.
(författare)
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The velocity distribution of white dwarfs in Gaia EDR3
- 2022
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Ingår i: Monthly Notices of the Royal Astronomical Society. - : Oxford University Press (OUP). - 0035-8711 .- 1365-2966. ; 512:4, s. 6201-6216
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Tidskriftsartikel (refereegranskat)abstract
- Using a penalized maximum likelihood, we estimate, for the first time, the velocity distribution of white dwarfs in the solar neighbourhood. Our sample consists of 129 675 white dwarfs within 500 pc in Gaia Early Data Release 3. The white dwarf velocity distributions reveal a similar structure to the rest of the solar neighbourhood stars, reflecting that white dwarfs are subject to the same dynamical processes. In the velocity distribution for three magnitude-binned subsamples, we, however, find a novel structure at (U, V) = (7,-19) km s-1 in fainter samples, potentially related to the Coma Berenices stream. We also see a double-peaked feature in U-W at U ≈-30 km s-1 and in V-W at V ≈-20 km s-1 for fainter samples. We determine the velocity distribution and velocity moments as a function of absolute magnitude for two samples based on the bifurcation identified in Gaia Data Release 2 in the colour-magnitude diagram. The brighter, redder sequence has a larger velocity dispersion than the fainter, bluer sequence across all magnitudes. It is hard to reconcile this kinematic difference with a bifurcation caused purely by atmospheric composition, while it fits neatly with a significant age difference between the two sequences. Our results provide novel insights into the kinematic properties of white dwarfs and demonstrate the power of analytical techniques that work for the large fraction of stars that do not have measured radial velocities in the current era of large-scale astrometric surveys.
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| 43. |
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| 44. |
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| 45. |
- 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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| 46. |
- Riitonen, T, et al.
(författare)
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Chapter I : Engineering Aspects of Bioethanol Synthesis
- 2013. - 1
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Ingår i: Advances in Chemical Engineering. - : Academic Press. - 9780123865052 ; , s. 1-73
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Bokkapitel (refereegranskat)abstract
- This chapter examines the chemistry, technology, and engineering aspects of ethanol production from different biomass sources. The occurrence, structure, and processing of natural sugars, particularly, those obtained from lignocellulose materials, into fermentable units for bioethanol are reviewed. In addition, different industrial technologies for the fractionation of lignocellulosic materials for the production of bioethanol as a fuel and platform chemical are discussed. Finally, the synthetic routes for bioethanol production processes and the catalytic upgrading processes are addressed.
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| 47. |
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| 48. |
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| 49. |
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| 50. |
- Soudham, Venkata Prabhakar, et al.
(författare)
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Enzymatic hydrolysis of Norway spruce and sugarcane bagasse after treatment with 1-allyl-3-methylimidazolium formate
- 2013
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Ingår i: Journal of chemical technology and biotechnology (1986). - : Wiley. - 0268-2575 .- 1097-4660. ; 88:12, s. 2209-2215
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Enzymatic hydrolysis of cellulose in lignocellulosic materials suffers from slow reaction rates due to limited access to enzyme adsorption sites and to the high crystallinity of the cellulose. In this study, an attempt was made to facilitate enzymatic hydrolysis by pretreatment of cellulosic materials using the ionic liquid (IL) 1-allyl-3-methylimidazolium formate ([Amim][HCO2]) under mild reaction conditions. The effect of the IL was compared with that of thermochemical pretreatment under acidic conditions. RESULTS: The lignocellulosic substrates investigated were native and thermochemically pretreated Norway spruce and sugarcane bagasse. Microcrystalline cellulose (Avicel) was included for comparison. The IL treatments were performed in the temperature range 45-120°C and, after regeneration and washing of the cellulosic substrates, enzymatic saccharification was carried out at 45°C for 72h. After 12h of hydrolysis, the glucose yields from regenerated native spruce and sugarcane bagasse were up to nine times higher than for the corresponding untreated substrates. The results also show positive effects of pretreatment using [Amim][HCO2] on the hydrolysis of xylan and mannan. Conclusion: The present work demonstrates that both native wood and agricultural residues are readily soluble in [Amim][HCO2] under gentle conditions, and that pretreatment with ionic liquids such as [Amim][HCO2] warrants further attention as a potential alternative to conventional pretreatment techniques.
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