| 1. |
- Wan, Li, et al.
(författare)
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Engineering the sign of circularly polarized emission in achiral polymer - chiral small molecule blends as a function of blend ratio
- 2022
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Ingår i: Journal of Materials Chemistry C. - : ROYAL SOC CHEMISTRY. - 2050-7526 .- 2050-7534. ; 10:13, s. 5168-5172
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Tidskriftsartikel (refereegranskat)abstract
- Circularly polarized organic light-emitting diodes (CP-OLEDs) that demonstrate both state-of-the-art efficiency and strongly circularly polarized (CP) electroluminescence have proved a considerable technical challenge. Furthermore, multiple factors - from film thickness to device structure - have been shown to influence the sign of the emitted CP light, independent of the handedness (absolute stereochemistry) of the chiral emitter. Here we report CP-OLEDs using a blend of poly(9,9-dioctylfluorene-alt-bithiophene) (F8T2) and a chiral small molecule additive (1-aza[6]helicene, aza[6]H). We demonstrate CP-OLEDs with an impressive electroluminescence dissymmetry (g(EL)) > 0.3 and a current efficiency of 0.53 cd A(-1) and brightness of 3023 cd m(-2). While at low aza[6]H loadings, F8T2 blends are consistent with previous observations of CP dissymetric inversion as a function of film thickness/excitation mode, a higher loading of aza[6]H (similar to 40 wt%) removes such dependencies while retaining excellent g-factors. The materials disclosed will allow for further mechanistic studies of chiral polymeric materials and provide new opportunities for chiroptical optimisation in films and devices.
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| 2. |
- Almeida, Joao, et al.
(författare)
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NADH- vs NADPH-coupled reduction of 5-hydroxymethyl furfural (HMF) and its implications on product distribution in Saccharomyces cerevisiae.
- 2008
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Ingår i: Applied Microbiology and Biotechnology. - : Springer Science and Business Media LLC. - 1432-0614 .- 0175-7598. ; 78:6, s. 939-945
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Tidskriftsartikel (refereegranskat)abstract
- Saccharomyces cerevisiae alcohol dehydrogenases responsible for NADH-, and NADPH-specific reduction of the furaldehydes 5-hydroxymethyl-furfural (HMF) and furfural have previously been identified. In the present study, strains overexpressing the corresponding genes (mut-ADH1 and ADH6), together with a control strain, were compared in defined medium for anaerobic fermentation of glucose in the presence and absence of HMF. All strains showed a similar fermentation pattern in the absence of HMF. In the presence of HMF, the strain overexpressing ADH6 showed the highest HMF reduction rate and the highest specific ethanol productivity, followed by the strain overexpressing mut-ADH1. This correlated with in vitro HMF reduction capacity observed in the ADH6 overexpressing strain. Acetate and glycerol yields per biomass increased considerably in the ADH6 strain. In the other two strains, only the overall acetate yield per biomass was affected. When compared in batch fermentation of spruce hydrolysate, strains overexpressing ADH6 and mut-ADH1 had five times higher HMF uptake rate than the control strain and improved specific ethanol productivity. Overall, our results demonstrate that (1) the cofactor usage in the HMF reduction affects the product distribution, and (2) increased HMF reduction activity results in increased specific ethanol productivity in defined mineral medium and in spruce hydrolysate.
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| 3. |
- Conte, Ricardo Pezoa, et al.
(författare)
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Bioethanol production from the green alga ulva rigida and the brown algae macrocystis pyrifera
- 2015
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Ingår i: NWBC 2015. - : VTT Technical Research Centre of Finland. - 9789513883539 ; , s. 319-325
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Konferensbidrag (refereegranskat)abstract
- Macroalgae are suitable bioresources to be explored as raw material for bioethanol production, as about 40 wt.% of its mass is composed of carbohydrates and they completely lack lignin. In this work the simultaneous saccharification and fermentation (SSF) of the green alga Ulva rigida and the brown alga Macrocystis pyrifera was performed. The algae were initially pretreated in deionized water or diluted sulfuric acid at 125°C in an autoclave for 60 min, respectively. Commercial cellulolytic enzymes and yeast were used for ethanol production. The carbohydrate composition of the fresh alga, pretreated alga and glucose and ethanol concentrations in the SSF processing are given. The water pretreatment solubilized 82 wt.% of the ulvan (rhamno-glucuroxylan) contained in U. rigida and 73 wt.% of the glucan remained in the residue. The diluted acid treatment removed 93 wt.% of the carbohydrates contained in U. rigida. The SSF of U. rigida pretreated with water produced 0.47 g EtOH/g sugar, with a 92 wt.% theoretical yield. In turn, water and diluted acid pretreatment of M. pyrifera increased 8.4 and 14.8 fold the carbohydrate content in the pretreated alga compared to the SSF of the fresh alga. The SSF of M. pyrifera pretreated with dilute sulfuric acid produced 0.15 g EtOH/g sugar, 29 wt.% theoretical yield. The production of ethanol was demonstrated for U. rigida and M. pyrifera with mild pretreatments. Especially in case of U. rigida simple water treatment allows to isolate ulvan for other purposes and efficiently ferment the remaining fibers.
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| 4. |
- Jilvero, Henrik, 1984, et al.
(författare)
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Equilibrium measurements of the NH3-CO2-H2O system - measurement and evaluation of vapor-liquid equilibrium data at low temperatures
- 2015
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Ingår i: Fluid Phase Equilibria. - : Elsevier BV. - 0378-3812. ; 385, s. 237-247
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Tidskriftsartikel (refereegranskat)abstract
- The equilibrium behavior of carbon dioxide (CO2) in aqueous ammonia at low temperatures was studied by means of experiments and modeling. The low-temperature conditions of this system are of interest for the development of ammonia-based CO2 capture. This study includes experimental analyses of the vapor and liquid phases to determine the fate of CO2 in aqueous ammonia. The partial pressure of CO2 at equilibrium was measured in a gas chromatograph. The vapor phase was assessed with ammonia concentrations at 5 and 10 wt%, CO2-loadings in the range of 0.15-0.75, and at the temperatures of 10 degrees C, 20 degrees C, and 40 degrees C. The liquid-phase carbon distribution was determined based on Raman spectroscopy and partial least-squares regression modeling. Speciation of the liquid phase was determined at 5 wt% and 10 wt%, CO2-loadings in the range of 0-0.6, and room temperature (25 degrees C). Two thermodynamic models of the NH3-CO2-H2O system were evaluated with respect to the measured data. For the prediction of the partial pressure of CO2, the model devised by Que and Chen [6] proved to be the most accurate, while for the liquid-phase predictions, there was no significant difference between the models in terms of accuracy.
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| 5. |
- Naurin, Elin, 1975, et al.
(författare)
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Does transition to parenthood affect gender traits? The effect of pregnancy on perceived female and male traits
- 2021
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Ingår i: European Journal of Politics and Gender. - 2515-1088 .- 2515-1096. ; 4:1, s. 135-150
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Tidskriftsartikel (refereegranskat)abstract
- Key messages We study the effect of a gendered life event on changes in gender identity during adulthood. Pregnant women and partners of pregnant women are followed over time, with pre- and post-test measures of gender identity. While pregnancy and childbirth are often seen as reinforcing feminine identity, we expect only small changes in a gender-equal society like Sweden. Results show that gender identity is stable during pregnancy and around childbirth for Swedish women and men.
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