Browsing by Subject "CONVERSION"

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  • Zhang, Rui; Eronen, Aleksi; Du, Xiangze; Ma, Enlu; Guo, Ming; Moslova, Karina; Repo, Timo (2021)
    The synthesis of new types of furan-based compounds other than 5-hydroxymethylfurfural from glucose is a very attractive yet underexploited strategy. We report here a catalytic conversion of glucose with acetylacetone (acac) to furan-centered chemicals, 2-methyl-3-acetylfuran (MAF) and 1-(5-(1,2-dihydroxyethyl)-2-methylfuran-3-yl)ethan-1-one (DMAF), which are potential building blocks for the synthesis of fine chemicals. The experimentally supported reaction mechanism is cascade-type, including glycolaldehyde (GA) formation by H2MoO4-catalysed retro-aldol condensation (C2 + C4) of glucose and immediate capture of transient C2 and C4 intermediates by acac to yield MAF and DMAF. To the best of our knowledge, this is the first report on the straightforward synthesis of MAF and DMAF from glucose, providing a new but generic synthesis strategy for GA-based C2 and erythrose-based C4 chemistry in biorefining.
  • Ravikumar, Ashwin; Larjavaara, Markku; Larson, Anne; Kanninen, Markku (2017)
    Revenues derived from carbon have been seen as an important tool for supporting forest conservation over the past decade. At the same time, there is high uncertainty about how much revenue can reasonably be expected from land use emissions reductions initiatives. Despite this uncertainty, REDD+ projects and conservation initiatives that aim to take advantage of available or, more commonly, future funding from carbon markets have proliferated. This study used participatory multi-stakeholder workshops to develop divergent future scenarios of land use in eight landscapes in four countries around the world: Peru, Indonesia, Tanzania, and Mexico. The results of these future scenario building exercises were analyzed using a new tool, CarboScen, for calculating the landscape carbon storage implications of different future land use scenarios. The findings suggest that potential revenues from carbon storage or emissions reductions are significant in some landscapes (most notably the peat forests of Indonesia), and much less significant in others (such as the low-carbon forests of Zanzibar and the interior of Tanzania). The findings call into question the practicality of many conservation programs that hinge on expectations of future revenue from carbon finance. The future scenarios-based approach is useful to policy-makers and conservation program developers in distinguishing between landscapes where carbon finance can substantially support conservation, and landscapes where other strategies for conservation and land use should be prioritized.
  • Niemi, Teemu Yrjö Manuel; Fernández, Israel; Steadman, Bethany; Mannisto, Jere Kristian; Repo, Timo Juhani (2018)
    We report herein a straightforward general method for the synthesis of cyclic carbamates from amino alcohols and carbon dioxide in the presence of an external base and a hydroxyl group activating reagent. Utilizing p-toluenesulfonyl chloride (TsCl), the reaction proceeds under mild conditions, and the approach is fully applicable to the preparation of various high value-added 5- and 6-membered rings as well as bicyclic fused ring carbamates. DFT calculations and experimental results indicate a SN2-type reaction mechanism with high regio-, chemo-, and stereoselectivity.
  • Tuunainen, Petra; Koivunen, Erja; Valaja, Jarmo; Valkonen, Eija; Hiidenhovi, Jaakko; Tupasela, Tuomo; Hongisto, Marja (2016)
    Performance, meat quality and litter quality were determined in 4000 male and female Ross 308 broilers fed on starter diet (soybean meal or rapeseed meal and peas) and grower-finisher diets based on either soybean meal (control) or substituting rapeseed meal or rapeseed meal and pea in different proportions (100/0%, 75/25% or 50/50%) for soybean meal in iso-nitrogenous basis. Performance of the birds fed with soybean meal diets was superior compared to that of the birds fed with rapeseed meal and pea based diets. Bird performance was the poorest and mortality the highest for the birds fed with the rapeseed meal grower diet. In this experiment birds did not reach performance target for the age and strain of bird. Overall, diet based solely on rapeseed meal protein is not suitable for broiler production. However, dietary rapeseed meal inclusion clearly improved fatty acid profile of breast meat. The omega-6/omega-3-ratio was 4.1, 2.4 and 2.7 for soybean meal, rapeseed meal, and rapeseed meal and peas based diets, respectively. There were no differences in sensory quality evaluation of breast meat between the treatments.
  • Montonen, Risto; Kassamakov, Ivan; Lehmann, Peter; Österberg, Kenneth; Haeggström, Edward (2018)
    The group refractive index is important in length calibration of Fourier domain interferometers by transparent transfer standards. We demonstrate accurate group refractive index quantification using a Fourier domain short coherence Sagnac interferometer. Because of a justified linear length calibration function, the calibration constants cancel out in the evaluation of the group refractive index, which is then obtained accurately from two uncalibrated lengths. Measurements of two standard thickness coverslips revealed group indices of 1.5426 +/- 0.0042 and 1.5434 +/- 0.0046, with accuracies quoted at the 95% confidence level. This agreed with the dispersion data of the coverslip manufacturer and therefore validates our method. Our method provides a sample specific and accurate group refractive index quantification using the same Fourier domain interferometer that is to be calibrated for the length. This reduces significantly the requirements of the calibration transfer standard. (C) 2018 Optical Society of America
  • Lindgren, Noora; Kaprio, Jaakko; Rinne, Juha; Vuoksimaa, Eero (2019)
    Objective To investigate the effect of familial risk for dementia on verbal learning by comparing cognitively healthy twins who had demented co-twins with cognitively healthy twins who had cognitively healthy co-twins. Methods 4367 twins aged >= 65 years including 1375 twin pairs (533 monozygotic (MZ), 823 dizygotic (DZ) and 19 unknown zygosity pairs) from a population-based Finnish Twin Cohort participated in a cross-sectional telephone assessment for dementia and in a single free recall trial of a 10-item word list. Results Cognitively healthy twins with demented co-twins (n=101 pairs) recalled less words than cognitively healthy twins with cognitively healthy co-twins (n=770 pairs) after adjusting for age, sex and education, B=-0.44, 95% C I (-0.73 to -0.14), p=0.003. The effect size was similar in MZ (n=31) twins (3.88 vs 4.29 words, B=-0.41, 95% C I (-0.96 to 0.13)) and DZ (n=66) twins (3.70 vs 4.17 words, B=-0.47, 95% C I (-0.84 to -0.10)). The heritability estimate of immediate recall (IR) was 0.37, 95% C I (0.21 to 0.43). Conclusions The results demonstrate that familial risk for dementia is reflected in the IR performance of cognitively healthy older persons. The finding of poorer IR performance in non-affected siblings compared with the general population, together with substantial heritability of IR, supports IR as a useful endophenotype for molecular genetic studies of dementia.
  • Al-Ani, Anas Aaqel Salim Salim; Stape, Thiago Henrique Scarabello; Mutluay, Murat; Tjäderhane, Leo; Tezvergil-Mutluay, Arzu (2019)
    Objective: To understand dimethyl sulfoxide (DMSO) interaction with distinct methacrylate monomer blends and the impact on polymer formation by investigating the combined relationship among degree of resin hydrophilicity, presence of DMSO and specific physico/mechanical properties. Methods: One hydrophobic (R2) and one hydrophilic (R5) methacrylate-based resins with different monomer compositions were solvated in ascending DMSO concentrations (0, 0.01, 0.1, 1, 5, and 10 w/w %). Neat resins (0 w/w % DMSO) were used as controls. The degree of conversion was determined by Fourier-transform infrared spectroscopy. Polymer crosslinking density was indirectly measured by a modified ethanol-water two-stage solvation technique and the biaxial flexural strength was measured after 24 h and 30 days of water storage at 37 degrees C. Water sorption and solubility were gravimetrically assisted during 28 days of water storage to determine the kinetics of water-polymer interactions. Data were analyzed by ANOVA and Tukey test (alpha = 0.05). Results: Incorporation of high DMSO-concentrations significantly increased the degree of conversion of all tested formulations, specifically for the hydrophobic resin (p <0.05). Despite the increase in degree of monomer conversion, higher water sorption/solubility values and lower biaxial flexure strengths were detected as a result of reductions in polymer crosslink density (p <0.05). In general, low DMSO-concentrations had no impact on the biaxial flexural strength, crosslinking density and water sorption/solubility (p <0.05). Conclusion: DMSO-monomer ratio and monomer composition are critical for new dental methacrylate-based adhesive formulations. High DMSO incorporation hampers physico/mechanical properties of methacrylate bonding resins, albeit to a lesser extend when hydrophilic resins are employed. Nonetheless, DMSO-solvated hydrophobic adhesives extensively outperform their hydrophilic correspondents. DMSO incorporation of 1 w/w % may constitute a secure threshold regardless of monomer composition.
  • Tossavainen, Marika; Ilyass, Usman; Ollilainen, Velimatti; Valkonen, Kalle; Ojala, Anne; Romantschuk, Martin (2019)
    Nitrogen limitation is considered a good strategy for enhancement of algal lipid production while conversely N repletion has been shown to result in biomass rich in proteins. In this study, the influence of long-term N limitation on Euglena gracilis fatty acid (FA), protein, chlorophyll a, and carotenoid concentrations was studied in N limited cultures. Biomass composition was analyzed from three-time points from N starved late stationary phase cultures, exposed to three different initial N concentrations in the growth medium. Total lipid content increased under N limitation in ageing cultures, but the low N content and prolonged cultivation time resulted in the formation of a high proportion of saturated FAs. Furthermore, growth as well as the production of proteins, chlorophyll a and carotenoids were enhanced in higher N concentrations and metabolism of these cellular components stayed stable during the stationary growth phase. Our findings showed that a higher N availability and a shorter cultivation time is a good strategy for efficient E. gracilis biomass production, regardless of whether the produced biomass is intended for maximal recovery of polyunsaturated FAs, proteins, or photosynthetic pigments. Additionally, we showed an increase of neoxanthin, beta-carotene, and diadinoxanthin as a response to higher N availability.
  • Friman, Styrbjorn; Tisone, Giuseppe; Nevens, Frederik; Lehner, Frank; Santaniello, Walter; Bechstein, Wolf O.; Zhuvarel, Sergey; Isoniemi, Helena; Rummo, Oleg O.; Klempnauer, Juergen; Anaokar, Swapneel; Hurst, Martin; Kazeem, Gbenga; Undre, Nasrullah; Trunecka, Pavel (2021)
    Background. Immunosuppression with calcineurin inhibitors (CNIs) is reportedly associated with risk of renal impairment in liver transplant recipients. It is believed that this can be mitigated by decreasing initial exposure to CNIs or delaying CNI introduction until 3-4 d posttransplantation. The ADVAGRAF studied in combination with mycophenolate mofetil and basili ximab in liver transplantation (DIAMOND) trial evaluated different administration strategies for prolonged-release tacrolimus (PR-T). Methods. DIAMOND was a 24-wk, open-label, phase 3b trial in de novo liver transplant recipients randomized to: PR-T 0.2 mg/kg/d (Arm 1); PR-T 0.15-0.175 mg/kg/d plus basiliximab (Arm 2); or PR-T 0.2 mg/kg/d delayed until day 5 posttransplant plus basiliximab (Arm 3). In a 5-y follow-up, patients were maintained on an immunosuppressive regimen according to standard clinical practice (NCT02057484). Primary endpoint: graft survival (Kaplan-Meier analysis). Results. Follow-up study included 856 patients. Overall graft survival was 84.6% and 73.5% at 1 and 5 y post transplant, respectively. Five-year rates for Arms 1, 2, and 3 were 74.7%, 71.5%, and 74.5%, respectively. At 5 y, death-censored graft survival in the entire cohort was 74,7%. Overall graft survival in patients remaining on PR-T for z30 d was 79.1%. Graft survival in patients who remained on PR-T at 5 y was 87.3%. Patient survival was 86.6% at 1 y and 76.3% at 5 y, with survival rates similar in the 3 treatment arms at 5 y. Estimated glomerular filtration rate at the end of the 24-wk initial study and 5 y posttransplant was 62.1 and 61.5 mi./min/1.73 m(2), respectively, and was similar between the 3 treatment arms at 5 y. Overall, 18 (2.9%) patients had z1 adverse drug reaction, considered possibly related to PR-T in 6 patients. Conclusions. In the DIAMOND study patient cohort, renal function, graft survival, and patient survival were similar between treatment arms at 5 y posttransplant.
  • Mkrtchyan, Satenik; Jakubczyk, Michal; Lanka, Suneel; Yar, Muhammad; Ayub, Khurshid; Shkoor, Mohanad; Pittelkow, Michael; Iaroshenko, Viktor O. (2021)
    We communicate two mild, solvent-free mechanochemical coupling transformations of CF3 group with nitro compounds into amides or Schiff bases employing Ytterbia as a catalyst. This process proceeds via C-F bond activation, accompanied with utilisation of Si-based reductants/oxygen scavengers - reductants of the nitro group. The scope and limitations of the disclosed methodologies are thoroughly studied. To the best of our knowledge, this work is the first example of mechanical energy promoted transformation of the inert CF3 group into other functionalities.
  • Wrigstedt, P.; Keskiväli, J.; Repo, T. (2016)
    We describe herein an efficient microwave-assisted aqueous biphasic dehydration of carbohydrates to 5-hydroxymethylfurfural (HMF). The effects of several alkali metal salts in aqueous phase, organic solvents as an extractive phase and Lewis acids are evaluated on the reaction. Specifically, starting from fructose, the use of bromide salts in aqueous phase and the common organic solvent MeCN or lignocellulose-derived gamma-valerolactone (GVL) as organic extractors are highly beneficial, leading to excellent HMF yields of up to 91% with HCl as a Bronsted acid catalyst. In conjunction with an isomerization catalyst, the method was applicable to glucose as well as various disaccharides and cellulose, affording HMF in notably good yields, particularly with GVL as an extractor and reusable Amberlyst-38(wet) as an acid catalyst. The exceptionally high HMF yields obtained in aqueous solutions is attributed to the combined effect of the biphasic reaction system and the application of microwaves, which ensures short reaction times and minimized by-product formation thereof.
  • Angileri, A.; Sardini, P.; Beaufort, D.; Amiard, G.; Beaufort, M. F.; Nicolai, J.; Siitari-Kauppi, M.; Descostes, M. (2020)
    In highly permeable sedimentary rock formations, U extraction by in-situ leaching techniques (ISR - In-Situ Recovery) is generally considered to have a limited environmental impact at ground level. Significantly, this method of extraction produces neither mill tailings nor waste rocks. Underground, however, the outcome for U-238 daughter elements in aquifers is not well known because of their trace concentrations in the host rocks. Thus, understanding the in-situ mobility of these elements remains a challenge. Two samples collected before and after six months of ISR experiments (Dulaan Uul, Mongolia) were studied with the help of a digital autoradiography technique (DA) of alpha particles, bulk alpha spectrometry, and complementary petrographic observation methods. These techniques demonstrate that before and after leaching, the radioactivity is concentrated in altered and microporous Fe-Ti oxides. Most of the daughter elements of U remain trapped in the rock after the leaching process. DA confirms that the alpha activity of the Fe-Ti oxides remains high after uranium leaching, and the initial secular equilibrium of the U-238 series for Th-230 to Po-210 daughter elements (including Ra-226) of the fresh rocks is maintained after leaching. While these findings should be confirmed by more systematic studies, they already identify potential mechanisms explaining why the U-daughter concentrations in leaching water are low.
  • Rossi, Jussi; Rossi, Jussi; Sharma, Sucheta; Laurila, Toni; Teissier, Roland; Baranov, Alexei; Ikonen, Erkki; Vainio, Markku (2021)
    We present an experimental comparison of photoacoustic responsivities of common highly absorbing carbon based materials. The comparison was carried out with parameters relevant for photoacoustic power detectors and Fourier-transform infrared (FTIR) spectroscopy: we covered a broad wavelength range from the visible red to far infrared (633 nm to 25 mu m) and the regime of low acoustic frequencies (< 1 kHz). The investigated materials include a candle soot-based coating, a black paint coating and two different carbon nanotube coatings. Of these, the low-cost soot absorber produced clearly the highest photoacoustic response over the entire measurement range.
  • Korkalo, Pasi; Hagner, Marleena; Janis, Janne; Makinen, Marko; Kaseva, Janne; Lassi, Ulla; Rasa, Kimmo; Jyske, Tuula (2022)
    The pyroligneous acids (PAs) of woody biomass produced by torrefaction have pesticidal properties. Thus, PAs are potential alternatives to synthetic plant protection chemicals. Although woody biomass is a renewable feedstock, its use must be efficient. The efficiency of biomass utilization can be improved by applying a cascading use principle. This study is novel because we evaluate for the first time the pesticidal potential of PAs derived from the bark of hybrid aspen (Populus tremula L. x Populus tremuloides Michx.) and examine simultaneously how the production of the PAs can be interlinked with the cascade processing of hybrid aspen biomass. Hybrid aspen bark contains valuable extractives that can be separated before the hemicellulose is thermochemically converted into plant protection chemicals. We developed a cascade processing scheme, where these extractives were first extracted from the bark with hot water (HWE) or with hot water and alkaline alcohol (HWE+AAE) prior to their conversion into PAs by torrefaction. The herbicidal performance of PAs was tested using Brassica rapa as the test species, and the fungicidal performance was proven using Fusarium culmorum. The pesticidal activities were compared to those of the PAs of debarked wood and of commercial pesticides. According to the results, extractives can be separated from the bark without overtly diminishing the weed and fungal growth inhibitor performance of the produced PAs. The HWE of the bark before its conversion into PAs appeared to have an enhancing effect on the herbicidal activity. In contrast, HWE+AAE lowered the growth inhibition performance of PAs against both the weeds and fungi. This study shows that hybrid aspen is a viable feedstock for the production of herbicidal and fungicidal active chemicals, and it is possible to utilize biomass according to the cascading use principle.
  • Teles, Camila A.; Rabelo-Neto, Raimundo C.; Duong, Nhung; Quiroz, Jhon; Camargo, Pedro H. C.; Jacobs, Gary; Resasco, Daniel E.; Noronha, Fabio B. (2020)
    In this work, the effect of interfacial sites between Pd particles and Nb2O5 species is investigated by testing a series of Pd-Nb2O5/SiO2 catalysts with different niobium loadings for the HDO reaction of phenol in the gas phase. Important differences in the selectivity to deoxygenated product were observed depending on the presence of niobium oxide close to Pd particles, which reveals the key role of the type of active phase in the control of reaction steps. It was found that Pd/SiO2 catalyst promotes hydrogenation pathways, producing cyclohex-anone as the major product. For Pd-Nb2O5/SiO2 catalyst containing a Nb/Pd molar ratio of 0.5, a sharp increase in the selectivity to benzene is observed (7.5-fold). Increasing the Nb/Pd molar ratio, the formation of benzene is enhanced. The results showed that the Pd-Nb2O5 interface, composed by an oxophilic oxide in the perimeter of the metal particle, is responsible for the activation of the C-O bond, promoting the deoxygenation reaction.
  • Buffiere, Jean; Ahvenainen, Patrik; Borrega, Marc; Svedström, Kirsi; Sixta, Herbert (2016)
    This work discusses the suitability of supercritical water treatment (SCWT) for depolymerising microcrystalline cellulose in a controlled way. The SCWT partially hydrolysed cellulose down to a mixture of three valuable products: water-insoluble low-molecular-weight cellulose (WI-LMWC) precipitate, water-soluble low-molecular-weight cellulose (WS-LMWC) oligomers, and glucose. The conditions under which the energy demand for obtaining these products is minimised were identified by adjusting the reaction time inside the continuous reactor and the temperature around the critical point. The optimum conditions were 370 degrees C and 0.4 seconds for producing WI-LMWC and 360 degrees C and 0.5 seconds for producing WS-LMWC, with maximum yields of 19 wt% and 50 wt%, respectively. This work also shows that the water-insoluble product precipitates into crystalline cellulose II arrangements. This precipitation phenomenon enabled isolation of cellulose chains of different lengths according to their respective solubilities in ambient water. The results show that SCWT is a relevant process for producing narrowly distributed fractions of low-molecular-weight cellulose using water and heat only.
  • Koivunen, Erja; Talvio, Eija; Valkonen, Eija; Tupasela, Tuomo; Tuunainen, Petra; Valaja, Jarmo (2016)
    The aim was to study the effects of dietary pea inclusion and the addition of Avizyme 1200 -enzyme cocktail on broiler performance, intestinal viscosity and organoleptic quality of meat. The experimental design was a 4 x 2 factorial, the factors being dietary pea inclusion (0, 150, 300 and 450 g kg(-1)) in the diets fed from day 9 to day 38 and the addition of Avizyme 1200 enzyme cocktail including amylase, protease and xylanase during the entire experiment. The growth of birds improved (p 0.05). In conclusion, 450 g kg(-1) peas can be used in the broiler grower diets without negative effects on the bird performance. The use of enzyme cocktail improves bird performance.