| 1. |
- Munthe, Christian, 1962
(author)
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Precaution and Ethics: Handling risks, uncertainties and knowledge gaps in the regulation of new biotechnologies
- 2017
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Book (other academic/artistic)abstract
- This volume outlines and analyses ethical issues actualized by applying a precautionary approach to the regulation of new biotechnologies. It presents a novel way of categorizing and comparing biotechnologies from a precautionary standpoint. Based on this, it addresses underlying philosophical problems regarding the ethical assessment of decision-making under uncertainty and ignorance, and discusses how risks and possible benefits of such technologies should be balanced from an ethical standpoint. It argues on conceptual and ethical grounds for a technology neutral regulation as well as for a regulation that not only checks new technologies but also requires old, inferior ones to be phased out. It demonstrates how difficult ethical issues regarding the extent and ambition of precautionary policies need to be handled by such a regulation, and presents an overarching framework for doing so.
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| 2. |
- Anasontzis, George E, 1980
(author)
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Biomass modifying enzymes: From discovery to application
- 2012
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In: Oral presentation at the Chalmers Life Science AoA conference.
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Conference paper (other academic/artistic)abstract
- It has now been realized that the road towards the bio-based economy is a one-way street, leaving gradually the oil-based technology and driving slowly towards a more sustainable society. The current non-biodegradable hydrocarbon fuels and plastics will be replaced by new products which will derive from natural and renewable resources. The synthesis of such biofuels and biochemicals is still challenged by the difficulties to cost efficiently degrade lignocellulosic material to fermentable sugars or to isolate the intact polymers. Biomass degrading and modifying enzymes play an integral role both in the separation of the polymers from the wood network, as well as in their subsequent modification, prior to further product development.Our group interests focus on all levels of applied enzyme research of biomass acting enzymes: Discovery, assay development, production and application. Relevant examples will be provided: What is our strategy for discovering novel microorganisms and enzymes from the tropical forests and grasslands of Vietnam? How do we design novel real-world assays for enzyme activity determination? Which are the bottlenecks in the enzymatic cellulose hydrolysis? How enzymes can be used to produce high added value compounds from biomass?
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| 3. |
- Jansson, Ronnie, et al.
(author)
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Functionalized silk assembled from a recombinant spider silk fusion protein (Z-4RepCT) produced in the methylotrophic yeast Pichia pastoris
- 2016
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In: Biotechnology Journal. - : Wiley-VCH Verlagsgesellschaft. - 1860-6768 .- 1860-7314. ; 11:5, s. 687-699
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Journal article (peer-reviewed)abstract
- Functional biological materials are a growing research area with potential applicability in medicine and biotechnology. Using genetic engineering, the possibility to introduce additional functions into spider silk-based materials has been realized. Recently, a recombinant spider silk fusion protein, Z-4RepCT, was produced intracellularly in Escherichia coli and could after purification self-assemble into silk-like fibers with ability to bind antibodies via the IgG-binding Z domain. In this study, the use of the methylotrophic yeast Pichia pastoris for production of Z-4RepCT has been investigated. Temperature, pH and production time were influencing the amount of soluble Z-4RepCT retrieved from the extracellular fraction. Purification of secreted Z-4RepCT resulted in a mixture of full-length and degraded silk proteins that failed to self-assemble into fibers. A position in the C-terminal domain of 4RepCT was identified as being subjected to proteolytic cleavage by proteases in the Pichia culture supernatant. Moreover, the C-terminal domain was subjected to glycosylation during production in P. pastoris. These observed alterations of the CT domain are suggested to contribute to the failure in fiber assembly. As alternative approach, Z-4RepCT retrieved from the intracellular fraction, which was less degraded, was used and shown to retain ability to assemble into silk-like fibers after enzymatic deglycosylation.
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| 4. |
- Shin, Jae Ho, 1987, et al.
(author)
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Molecular docking and linear interaction energy studies give insight to α, β-reduction of enoate groups in enzymes
- 2018
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Conference paper (other academic/artistic)abstract
- Production of adipic acid from renewable sources has been gaining attention in an attempt to move from an oil-based economy to a biobased economy. Metabolic engineering allows microorganisms to produce useful chemicals using renewable resources as carbon sources. We target a theoretical metabolic pathway that relies on conversion of L-lysine to adipic acid. One of the enzymatic steps in this conversion pathway is an α, β-reduction of an unsaturated bond in an enoate moiety and no aerobic enzymes have been identified to specifically make this conversion on 6-amino-trans-2-hexenoic acid. We evaluated Escherichia coli NemA, and Saccharomyces pastorianus Oye1 (Old Yellow Enzyme 1) for their potenstial capability to carry out the desired α, β-reduction. Here, we build homology models for E. coli NemA and perform molecular docking studies of trans-2-hexenoic acid and trans-2-hexenal to the candidate enzyme models. Ligand-enzyme binding stability is assessed by molecular dynamics (MD) simulations. Additionally, linear energy calculations were used to investigate binding stability in solution environment. Here, we propose that NemA and Oye1, both belonging to the Old yellow enzyme family, have large enough catalytic pocket for accommodating enoate moieties but not enough stability to carry out the α, β-reduction. Protein engineering of both NemA and Oye1 would be necessary for these enzymes to perform the targeted reactions efficiently. The results shown in this study provides a useful insight to α, β-reduction reaction potentially crucial in bio-based production of adipic acid.
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| 5. |
- Svensson, Sofie, et al.
(author)
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Fungal textiles : Wet spinning of fungal microfibers to produce monofilament yarns
- 2021
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In: Sustainable Materials and Technologies. - : Elsevier BV. - 2214-9937. ; 28
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Journal article (peer-reviewed)abstract
- The cell wall of a zygomycetes fungus was successfully wet spun into monofilament yarns and demonstrated as a novel resource for production of sustainable textiles. Furthermore, the fungus could be cultivated on bread waste, an abundant food waste with large negative environmental impact if not further utilized. Rhizopus delemar was first cultivated in bread waste in a bubble column bioreactor. The fungal cell wall collected through alkali treatment of fungal biomass contained 36 and 23% glucosamine and N-acetyl glucosamine representing chitosan and chitin in the cell wall, respectively. The amino groups of chitosan were protonated by utilizing acetic or lactic acid. This resulted in the formation of a uniform hydrogel of fungal microfibers. The obtained hydrogel was wet spun into an ethanol coagulation bath to form an aggregated monofilament, which was finally dried. SEM images confirmed the alignment of fungal microfibers along the monofilament axis. The wet spun monofilaments had tensile strengths up to 69.5 MPa and Young's modulus of 4.97 GPa. This work demonstrates an environmentally benign procedure to fabricate renewable fibers from fungal cell wall cultivated on abundant food waste, which opens a window to creation of sustainable fungal textiles.
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| 6. |
- Gontia, Paul, 1984, et al.
(author)
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Life cycle assessment of bio-based sodium polyacrylate production from pulp mill side streams: Case study of thermo-mechanical and sulfite pulp mills
- 2016
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In: Journal of Cleaner Production. - : Elsevier BV. - 0959-6526. ; 131, s. 475-484
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Journal article (peer-reviewed)abstract
- Sodium polyacrylate (Na-PA) is a super absorbent polymer, which is commonly used in diverse hygiene products. The polymer is currently produced from fossil feedstock and its production consequently leads to adverse environmental impacts. Na-PA production from sugars present in pulp mill side streams can potentially be a successful way to achieve a more sustainable production of this polymer. In order to guide the development of a novel biochemical process for producing Na-PA, a life cycle assessment was done in which Na-PA produced from side streams of thermo-mechanical pulp (TMP) and sulfite pulp mills were compared. Furthermore, a comparison was made with Na-PA produced from fossil resources. The results show that the main determinant of the environmental impact of the bio-based Na-PA production is the free sugar content in the side streams. The lowest environmental impact is achieved by the least diluted side streams. More diluted side streams require larger amounts of energy for concentration, and, if the diluted streams are not concentrated, processes such as hydrolysis and detoxification, and fermentation are the environmental hotspots. Furthermore, the higher the yield of the fermentation process, the lower the environmental impact will be. Lastly, the production of bio-based Na-PA led to a lower global warming potential for some of the considered pulp mill side streams, but all of the other impacts considered were higher, when compared to fossil-based Na-PA production. Therefore, in parallel with efforts to develop a high-yield yeast for the fermentation process, technology developers should focus on low energy concentration processes for the side streams.
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| 7. |
- Karlsson, Emma, 1983, et al.
(author)
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In silico and in vitro studies of the reduction of unsaturated α,β bonds of trans-2-hexenedioic acid and 6-amino-trans-2-hexenoic acid – Important steps towards biobased production of adipic acid
- 2018
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In: PLoS ONE. - : Public Library of Science (PLoS). - 1932-6203 .- 1932-6203. ; 13:2
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Journal article (peer-reviewed)abstract
- The biobased production of adipic acid, a precursor in the production of nylon, is of great interest in order to replace the current petrochemical production route. Glucose-rich lignocel-lulosic raw materials have high potential to replace the petrochemical raw material. A number of metabolic pathways have been proposed for the microbial conversion of glucose to adipic acid, but achieved yields and titers remain to be improved before industrial applications are feasible. One proposed pathway starts with lysine, an essential metabolite industrially produced from glucose by microorganisms. However, the drawback of this pathway is that several reactions are involved where there is no known efficient enzyme. By changing the order of the enzymatic reactions, we were able to identify an alternative pathway with one unknown enzyme less compared to the original pathway. One of the reactions lacking known enzymes is the reduction of the unsaturated α,β bond of 6-amino-trans-2-hexenoic acid and trans-2hexenedioic acid. To identify the necessary enzymes, we selected N-ethylmaleimide reductase from Escherichia coli and Old Yellow Enzyme 1 from Saccharomyces pastorianus. Despite successful in silico docking studies, where both target substrates could fit in the enzyme pockets, and hydrogen bonds with catalytic residues of both enzymes were predicted, no in vitro activity was observed. We hypothesize that the lack of activity is due to a difference in electron withdrawing potential between the naturally reduced aldehyde and the carboxylate groups of our target substrates. Suggestions for protein engineering to induce the reactions are discussed, as well as the advantages and disadvantages of the two metabolic pathways from lysine. We have highlighted bottlenecks associated with the lysine pathways, and proposed ways of addressing them.
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| 8. |
- Pajalic, Oleg, 1964
(author)
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BIOCHEMICALS, BIOMATERIALS, AND BIOINNOVATIONS – WHAT CAN WE GET FROM BIOMASS
- 2015
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In: 4th SCIENTIFIC SYMPOSIUM WITH INTERNATIONAL PARTICIPATION Environmental resources, sustainable development and food production OPORPH – 2015 Tuzla, Bosnia and Herzegovina November 12-13, 2015.
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Conference paper (other academic/artistic)abstract
- Environmental changes and oil price has triggered an increased interest in bio-based energy, chemicals and materials in the last decades. Thou the oil price have been dropped recently due to new findings, the transformation towards bio-based economy will continue. EU has pumped hundred millions of EURO in sustainability related research and innovation projects. Sweden has followed the pattern and has been pushed towards the green economy by establishing the vision to create and develop a bio-based economy in the first half of the twenty-first century. Sweden is rich with non-edible bio-mass i.e. forest. Traditionally the forest was used in pulp and paper industry, but digitalization boom requires paradigm shift. Green materials and green chemicals were identified as a big potential. Ambitious research was started supported by Swedish government and industry. Some of the industrial initiatives are:-The new research agenda, NRA 2020, is the collective assessment of Swedish forest-based industries regarding research, development and demonstration, which is necessary for the sector to be able to contribute to achieving. - Chemical cluster in Western Sweden started an initiative called Sustainable Chemistry 2030 with the vision that their business will be based on renewable feedstock and energy and contribute to sustainable society.
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| 9. |
- Spetea, Cornelia, 1968
(author)
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Energy-efficient cultivation of marine microalgae for biomass production : Final rapport: Energimyndigheten P45907-1
- 2020
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Reports (other academic/artistic)abstract
- This project has demonstrated the principle of rotational cultivation of marine microalgae and that species adapted to cold climates can provide higher productivity during cold periods. By using marine species, and thus seawater instead of freshwater in cultivation, the environmental impact is reduced. Society faces major challenges to produce sufficient amounts of biomass for energy and material, and microalgae have a great potential to complement sources from forestry and agriculture. At Nordic latitudes year-round microalgae cultivation is debatable due to seasonal variations in productivity. Shall the same species be used throughout the year or shall seasonal-adapted species be used? The aims of the project were to identify suitable algal strains for a potential annual rotation model, where different strains are rotated during three cultivation seasons, and to further develop and optimize an energy-efficient cultivation process for the marine environment. To achieve these aims, a laboratory study was performed where two marine microalgal strains out of 167 were selected for intended cultivation at the west coast of Sweden. One strain belongs to the species Nannochloropsis granulata and the other to Skeletonema marinoi. The strains were cultivated in three simulated growth seasons: summer, winter and spring, and thereafter compared. We show that Nannochloropsis produced more biomass with more incorporated energy in lipids during summer and spring (25 MJ kg-1 compared to about 45 MJ kg-1 for diesel), whereas Skeletonema produced more biomass rich in carbohydrates and proteins during winter. Skeletonema was in general more efficient in taking up phosphate. Based on our results, biomass production as energy feedstock would be energy efficient only during the summer on the Swedish west coast. Nevertheless, species could be rotated for different purposes during the year. Biomass production could be combined with nutrient recycling of wastewater, for example, from fish industry. Our project faces a challenge in boosting the biomass produced in winter, but this could be solved, for example, by optimization of the cultivation medium and temperature increase with heat wastewater or other heat waste. The summer species Nannochloropsis proved to withstand winter by activating different lipid metabolic pathways than the cold-adapted species Skeletonema uses. Enhanced synthesis of proteins, such as enzymes, in Skeletonema during winter may compensate for their reduced activities, promoting growth and biomass production even at low temperatures. More species need to be studied to find those with higher productivity under winter conditions. In practice, the work-related consequences of a rotational cultivation should be weighed against its benefits, relative to a shorter cultivation season in each application. Potential applications mainly include cleaning of air and seawater, production of energy, biomass and biomaterials for the industry.
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| 10. |
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| 11. |
- Gustafsson, Marcus, 1987-, et al.
(author)
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Climate performance of liquefied biomethane with carbon dioxide utilization or storage
- 2024
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In: Renewable and sustainable energy reviews. - : Elsevier. - 1364-0321 .- 1879-0690. ; 192
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Journal article (peer-reviewed)abstract
- In the process of upgrading biogas to biomethane for gas grid injection or use as a vehicle fuel, biogenic carbon dioxide (CO₂) is separated and normally emitted to the atmosphere. Meanwhile, there are a number of ways of utilizing CO₂ to reduce the dependency on fossil carbon sources. This article assesses the climate performance of liquefied biomethane for road transport with different options for utilization or storage of CO₂. The analysis is done from a life cycle perspective, covering the required and avoided processes from biogas production to the end use of biomethane and CO₂. The results show that all of the studied options for CO₂ utilization can improve the climate performance of biomethane, in some cases contributing to negative CO₂ emissions. One of the best options, from a climate impact perspective, is to use the CO₂ internally to produce more methane, although continuous supply of hydrogen from renewable sources can be a challenge. Another option that stands out is concrete curing, where CO₂ can both replace conventional steam curing and be stored for a long time in mineral form. Storing CO₂ in geological formations can also lead to negative CO₂ emissions. However, with such long-term storage solutions, opportunities to recycle biogenic CO₂ are lost, together with the possibility of de-fossilizing processes that require carbon, such as chemical production and horticulture.
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| 12. |
- Magnusson, Mikael, et al.
(author)
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Bioconversion of food waste to biocompatible wet-laid fungal films
- 2022
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In: Materials & design. - : Elsevier. - 0264-1275 .- 1873-4197. ; 216
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Journal article (peer-reviewed)abstract
- The fungus Rhizopus delemar was grown on bread waste in a submerged cultivation process and wet-laid into films. Alkali or enzyme treatments were used to isolate the fungal cell wall. A heat treatment was also applied to deactivate biological activity of the fungus. Homogenization of fungal biomass was done by an iterative ultrafine grinding process. Finally, the biomass was cast into films by a wet-laid process. Ultrafine grinding resulted in densification of the films. Fungal films showed tensile strengths of up to 18.1 MPa, a Young's modulus of 2.3 GPa and a strain at break of 1.4%. Highest tensile strength was achieved using alkali treatment, with SEM analysis showing a dense and highly organized structure. In contrast, less organized structures were obtained using enzymatic or heat treatments. A cell viability assay and fluorescent staining confirmed the biocompatibility of the films. A promising route for food waste valorization to sustainable fungal wet-laid films was established. © 2022 The Authors
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| 13. |
- Moaveni, Raouf, et al.
(author)
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Production of Polymeric Films from Orange and Ginger Waste for Packaging Application and Investigation of Mechanical and Thermal Characteristics of Biofilms
- 2024
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In: Applied Sciences. - 2076-3417. ; 14:11
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Journal article (peer-reviewed)abstract
- Citrus waste has been used as a source of bioplastics for research in different ways. Because the juice industry produces significant amounts of residue each year, it would be advantageous to use the byproducts in the creation of new materials. Researchers have long explored eco-friendly methods to convert citrus and other organic waste into polymers for producing biodegradable films. The goal of this study is to create biofilms from orange waste (OW) and ginger waste (GW) using an ultrafine grinder and study the films’ properties. Since pectin has the ability to gel, and because cellulosic fibers are strong, citrus waste has been studied for its potential to produce biofilms. After being washed, dried, and milled, orange and ginger waste was shaped into films using a casting process. Tensile testing was used to determine the mechanical properties of biofilms, while dynamic mechanical thermal analysis (DMTA), thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC) were used to determine their thermal properties. As the number of grinding cycles increased, the suspension’s viscosity increased from 29 mPa.s to 57 mPa.s for OW and from 217 mPa.s to 376 mPa.s for GW, while the particle size in the suspension significantly decreased. For OW and GW films, the highest tensile strength was 17 MPa and 15 MPa, respectively. The maximum strain obtained among all films was 4.8%. All the tested films were stable up to 150 °C, and maximum degradation occured after 300 °C.
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| 14. |
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| 15. |
- Agar, David, et al.
(author)
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A systematic study of ring-die pellet production from forest and agricultural biomass
- 2018
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In: Fuel Processing Technology. - : Elsevier BV. - 0378-3820 .- 1873-7188. ; 180, s. 47-55
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Journal article (peer-reviewed)abstract
- Continuous global growth in the pellet production industry and renewable energy policy targets have driven interest in under-utilised lignocellulosic biomass. In this comprehensive study, pelleting trials were systematically carried out using a pilot-scale ring-die pellet press with eight different biomass feedstock; logging residues, pine bark, wheat straw, reed canary grass, coppiced willow, poplar and beech. A standard spruce/pine sawdust blend was pelleted as a reference material.Pellets were produced from feedstock at four different moisture content levels, through two press channel lengths and three replicate steady-state sampling periods. A total of 192 batches of 8 mm diameter pellets were produced within a press channel length and moisture content range of 30-60 mm and 9-17% respectively. Pellet production had a range of 141-206 kg h(-1) and relatively good pellet quality was achieved for a majority of the studied feedstock. The best pellet batches had a mechanical durability and bulk density range of 91-99% and 532-714 kg m(-3) respectively, corresponding to an energy density range of 8.3-12.5 GJ m(-3) (as received). The extruded pellet temperature ranged between 99 and 131 degrees C and was correlated to pellet bulk density for hardwoods, pine bark and forest residues. The normalised energy (reference value of 1) used in pelleting all materials varied between 0.76 and 1.3 being highest for the hardwoods and lowest for straw and forest residues.
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| 16. |
- Andersson, Johanna, 1984, et al.
(author)
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Stick–slip motion and controlled filling speed by the geometric design of soft micro-channels
- 2018
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In: Journal of Colloid and Interface Science. - : Elsevier BV. - 1095-7103 .- 0021-9797. ; 524, s. 139-147
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Journal article (peer-reviewed)abstract
- Hypothesis Liquid can move by capillary action through interconnected porous materials, as in fabric or paper towels. Today mass transport is controlled by chemical modification. It is, however, possible to direct mass transport by geometrical modifications. It is here proposed that it is possible to tailor capillary flow speed in a model system of micro-channels by the angle, size and position of attached side channels. Experiments A flexible, rapid, and cost-effective method is used to produce micro-channels in gels. It involves 3D-printed moulds in which gels are cast. Open channels of micrometre size with several side channels on either one or two sides are produced with tilting angles of 10 – 170°. On a horizontal plane the meniscus of water driven by surface tension is tracked in the main channel. Findings The presence of side channels on one side slowed down the speed of the meniscus in the main channel least. Channels having side channels on both sides with tilting angles of up to 30° indicated tremendously slower flow, and the liquid exhibited a stick-slip motion. Broader side channels decreased the speed more than thinner ones, as suggested by the hypothesis. Inertial forces are suggested to be important in branched channel systems studied here.
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| 17. |
- De La Fuente, Teresa, et al.
(author)
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Life cycle assessment of decentralized mobile production systems for pelletizing logging residues under Nordic conditions
- 2018
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In: Journal of Cleaner Production. - : Elsevier BV. - 0959-6526 .- 1879-1786. ; 201, s. 830-841
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Journal article (peer-reviewed)abstract
- The development of mobile systems for the decentralized pelletizing of forest-based residual biomass is currently underway. However, there is a lack of knowledge regarding the environmental impacts of such systems that needs to be developed for correct judgements on the most sustainable developing paths. The objective of this study was to quantify and compare the environmental impacts of a decentralized mobile production system for pelletizing logging residues in Northern Sweden operating at either the forest landing or forest terminal from a Life Cycle Assessment (LCA) perspective.The results showed that the landing- and terminal-based scenarios showed similar environmental profiles. The pelleting, transportation and drying stages of both scenarios were identified as environmental hotspots. These production stages accounted for 62%, 14% and 14% of the total greenhouse gas emissions, respectively. Key factors influencing the system were the use of electricity at terminals, the increase in pelletizer capacity, and long transportation distances. The use of a Swedish electricity mix instead of diesel based electricity in the terminal-based scenario reduced all of the environmental impacts by between 68% and 83%, with the exception of fresh water eutrophication potential, which increased by 26%.In conclusion, our findings indicate that an electrified mobile pellet production system with high operational efficiency and situated at a terminal close to the harvesting sites could, from an LCA point of view, be an interesting option for pelletizing Nordic logging residues, especially in regions with long transportation distances to industry. (C) 2018 Elsevier Ltd. All rights reserved.
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| 18. |
- Fjellgaard Mikalsen, Ragni
(author)
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Fighting flameless fires : Initiating and extinguishing self-sustainedsmoldering fires in wood pellets
- 2018
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Doctoral thesis (other academic/artistic)abstract
- Smoldering fires represent domestic, environmental and industrial hazards. This flameless form of combustion is more easily initiated than flaming, and is also more persistent and difficult to extinguish. The growing demand for non-fossil fuels has increased the use of solid biofuels such as biomass. This represents a safety challenge, as biomass self-ignition can cause smoldering fires, flaming fires or explosions.Smoldering and extinguishment in granular biomass was studied experimentally. The set-up consisted of a cylindrical fuel container of steel with thermally insulated side walls. The container was closed at the bottom, open at the top and heated from below by a hot surface. Two types of wood pellets were used as fuel, with 0.75-1.5 kg samples.Logistic regression was used to determine the transition region between non-smoldering and self-sustained smoldering experiments, and to determine the influence of parameters. Duration of external heating was most important for initiation of smoldering. Sample height was also significant, while the type of wood pellet was near-significant and fuel container height was not.The susceptibility of smoldering to changes in air supply was studied. With a small gap at the bottom of the fuel bed, the increased air flow in the same direction as the initial smoldering front (forward air flow) caused a significantly more intense combustion compared to the normal set-up with opposed air flow.Heat extraction from the combustion was studied using a water-cooled copper pipe. Challenges with direct fuel-water contact (fuel swelling, water channeling and runoff) were thus avoided. Smoldering was extinguished in 7 of 15 cases where heat extraction was in the same range as the heat production from combustion. This is the first experimental proof-of-concept of cooling as an extinguishment method for smoldering fires.Marginal differences in heating and cooling separated smoldering from extinguished cases; the fuel bed was at a heating-cooling balance point. Lower cooling levels did not lead to extinguishment, but cooling caused more predictable smoldering, possibly delaying the most intense combustion. Also observed at the balance point were pulsating temperatures; a form of long-lived (hours), macroscopic synchronization not previously observed in smoldering fires.For practical applications, cooling could be feasible for prevention of temperature escalation from self-heating in industrial storage units. This study provides a first step towards improved fuel storage safety for biomass.
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| 19. |
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| 20. |
- Hao, Nanjing, et al.
(author)
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Glyconanomaterials for biosensing applications
- 2016
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In: Biosensors & bioelectronics. - : Elsevier. - 0956-5663 .- 1873-4235. ; 76:15, s. 113-130
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Journal article (peer-reviewed)abstract
- Nanomaterials constitute a class of structures that have unique physiochemical properties and are excellent scaffolds for presenting carbohydrates, important biomolecules that mediate a wide variety of important biological events. The fabrication of carbohydrate-presenting nanomaterials, glyconanomaterials, is of high interest and utility, combining the features of nanoscale objects with biomolecular recognition. The structures can also produce strong multivalent effects, where the nanomaterial scaffold greatly enhances the relatively weak affinities of single carbohydrate ligands to the corresponding receptors, and effectively amplifies the carbohydrate-mediated interactions. Glyconanomaterials are thus an appealing platform for biosensing applications. In this review, we discuss the chemistry for conjugation of carbohydrates to nanomaterials, summarize strategies, and tabulate examples of applying glyconanomaterials in in vitro and in vivo sensing applications of proteins, microbes, and cells. The limitations and future perspectives of these emerging glyconanomaterials sensing systems are furthermore discussed.
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| 21. |
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| 22. |
- Martinez Avila, Hector, 1985, et al.
(author)
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Biocompatibility evaluation of densified bacterial nanocellulose hydrogel as an implant material for auricular cartilage regeneration
- 2014
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In: Applied Microbiology and Biotechnology. - : Springer Science and Business Media LLC. - 1432-0614 .- 0175-7598. ; 98:17, s. 7423-7435
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Journal article (peer-reviewed)abstract
- Bacterial nanocellulose (BNC), synthesized by the bacterium Gluconacetobacter xylinus, is composed of highly hydrated fibrils (99 % water) with high mechanical strength. These exceptional material properties make BNC a novel biomaterial for many potential medical and tissue engineering applications. Recently, BNC with cellulose content of 15 % has been proposed as an implant material for auricular cartilage replacement, since it matches the mechanical requirements of human auricular cartilage. This study investigates the biocompatibility of BNC with increased cellulose content (17 %) to evaluate its response in vitro and in vivo. Cylindrical BNC structures (48 Au 20 mm) were produced, purified in a built-in house perfusion system, and compressed to increase the cellulose content in BNC hydrogels. The reduction of endotoxicity of the material was quantified by bacterial endotoxin analysis throughout the purification process. Afterward, the biocompatibility of the purified BNC hydrogels with cellulose content of 17 % was assessed in vitro and in vivo, according to standards set forth in ISO 10993. The endotoxin content in non-purified BNC (2,390 endotoxin units (EU)/ml) was reduced to 0.10 EU/ml after the purification process, level well below the endotoxin threshold set for medical devices. Furthermore, the biocompatibility tests demonstrated that densified BNC hydrogels are non-cytotoxic and cause a minimal foreign body response. In support with our previous findings, this study concludes that BNC with increased cellulose content of 17 % is a promising non-resorbable biomaterial for auricular cartilage tissue engineering, due to its similarity with auricular cartilage in terms of mechanical strength and host tissue response.
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| 23. |
- Martinez Avila, Hector, 1985
(author)
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Biofabrication, Biomechanics and Biocompatibility of Nanocellulose-based Scaffolds for Auricular Cartilage Regeneration
- 2015
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Doctoral thesis (other academic/artistic)abstract
- In about 2:10,000 births the external part of the ear, the auricle, is severely malformed or absent. Furthermore, tumors and trauma can cause defects to the auricle. For patients with dysplasia of the auricle, and especially for children, an inconspicuous outer appearance with life-like auricles is important for their psychological and emotional well being as well as their psycho-social development. Auricular reconstruction remains a great challenge due to the complexity of surgical reconstruction using rib cartilage. Despite the advances in stem cell technology and biomaterials, auricular cartilage tissue engineering (TE) is still in an early stage of development due to critical requirements demanding appropriate mechanical properties and shape stability of the tissue-engineered construct. This thesis has focused on developing patient-specific tissue-engineered auricles for one-step surgery using a novel biomaterial, bacterial nanocellulose (BNC), seeded with human nasoseptal chondrocytes (hNC) and bone marrow mononuclear cells (MNC).Biomechanical properties of human auricle cartilage were measured and used as a benchmark for tuning BNC properties. In order to meet the biomechanical requirements, a scaffold with bilayer architecture composed of a dense BNC support layer and a macroporous structure was designed. Firstly, the biocompatibility of the dense BNC layer was investigated, demonstrating a minimal foreign body response according to standards set forth in ISO 10993. Secondly, different methods to create macroporous BNC scaffolds were studied and the redifferentiation capacity of hNCs was evaluated in vitro; revealing that macroporous BNC scaffolds support cell ingrowth, proliferation and neocartilage formation. The bilayer BNC scaffold was biofabricated and tested for endotoxins and cytotoxicity before evaluating in long-term 3D culture, and subsequently in vivo for eight weeks—in an immunocompromised animal model. The results demonstrated that the non-pyrogenic and non- cytotoxic bilayer BNC scaffold offers a good mechanical stability and maintains a structural integrity, while providing a porous 3D environment that is suitable for hNCs and MNCs to produce neocartilage, in vitro and in vivo. Furthermore, patient-specific auricular BNC scaffolds with bilayer architecture were biofabricated and seeded with autologous rabbit auricular chondrocytes (rAC) for implantation in an immunocompetent rabbit model for six weeks. The results demonstrated the shape stability of the rAC-seeded scaffolds and neocartilage depositions in the immunocompetent autologous grafts. 3D bioprinting was also evaluated for biofabrication of patient-specific, chondrocyte-laden auricular constructs using a bioink composed of nanofibrillated cellulose and alginate. Bioprinted auricular constructs showed an excellent shape and size stability after in vitro culture. Moreover, this bioink supports redifferentiation of hNCs while offering excellent printability, making this a promising approach for auricular cartilage TE. Furthermore, the use of bioreactors is essential for the development of tissue-engineered cartilage in vitro. Thus, a compression bioreactor was utilized to apply dynamic mechanical stimulation to cell-seeded constructs as a means to enhance production of extracellular matrix in vitro.In this work, a potential clinical therapy for auricular reconstruction using tissue-engineered auricles is demonstrated; where BNC is proposed as a promising non-degradable biomaterial with good chemical and mechanical stability for auricular cartilage TE. Although the primary focus of this thesis is on auricular reconstruction, the methods developed are also applicable in the regeneration of other cartilage tissues such as those found in the nose, trachea, spine and articular joints.
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| 24. |
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| 25. |
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| 26. |
- Shin, Jae Ho, 1987, et al.
(author)
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Metabolic engineering of Corynebacterium glutamicum for enhanced production of 5-aminovaleric acid
- 2016
-
In: Microbial Cell Factories. - : Springer Science and Business Media LLC. - 1475-2859. ; 15:1
-
Journal article (peer-reviewed)abstract
- Background: 5-Aminovaleric acid (5AVA) is an important five-carbon platform chemical that can be used for the synthesis of polymers and other chemicals of industrial interest. Enzymatic conversion of l-lysine to 5AVA has been achieved by employing lysine 2-monooxygenase encoded by the davB gene and 5-aminovaleramidase encoded by the davA gene. Additionally, a recombinant Escherichia coli strain expressing the davB and davA genes has been developed for bioconversion of l-lysine to 5AVA. To use glucose and xylose derived from lignocellulosic biomass as substrates, rather than l-lysine as a substrate, we previously examined direct fermentative production of 5AVA from glucose by metabolically engineered E. coli strains. However, the yield and productivity of 5AVA achieved by recombinant E. coli strains remain very low. Thus, Corynebacterium glutamicum, a highly efficient l-lysine producing microorganism, should be useful in the development of direct fermentative production of 5AVA using l-lysine as a precursor for 5AVA. Here, we report the development of metabolically engineered C. glutamicum strains for enhanced fermentative production of 5AVA from glucose. Results: Various expression vectors containing different promoters and origins of replication were examined for optimal expression of Pseudomonas putida davB and davA genes encoding lysine 2-monooxygenase and delta-aminovaleramidase, respectively. Among them, expression of the C. glutamicum codon-optimized davA gene fused with His 6 -Tag at its N-Terminal and the davB gene as an operon under a strong synthetic H 36 promoter (plasmid p36davAB3) in C. glutamicum enabled the most efficient production of 5AVA. Flask culture and fed-batch culture of this strain produced 6.9 and 19.7 g/L (together with 11.9 g/L glutaric acid as major byproduct) of 5AVA, respectively. Homology modeling suggested that endogenous gamma-aminobutyrate aminotransferase encoded by the gabT gene might be responsible for the conversion of 5AVA to glutaric acid in recombinant C. glutamicum. Fed-batch culture of a C. glutamicum gabT mutant-harboring p36davAB3 produced 33.1 g/L 5AVA with much reduced (2.0 g/L) production of glutaric acid. Conclusions:Corynebacterium glutamicum was successfully engineered to produce 5AVA from glucose by optimizing the expression of two key enzymes, lysine 2-monooxygenase and delta-aminovaleramidase. In addition, production of glutaric acid, a major byproduct, was significantly reduced by employing C. glutamicum gabT mutant as a host strain. The metabolically engineered C. glutamicum strains developed in this study should be useful for enhanced fermentative production of the novel C5 platform chemical 5AVA from renewable resources.
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| 27. |
- Werker, Alan
(creator_code:cre_t)
-
Method for the recovery of stabilized polyhydroxyalkanoates from biomass that has been used to treat organic waste
- 2016
-
Patent (other academic/artistic)abstract
- The invention is directed to a method of increasing the chemical and/or thermal stability of PHA in biomass where the biomass is contained within mixed liquor, and wherein the mixed liquor is treated by a combination of removing water from the mixed liquor and pH adjustment of the mixed liquor or maintenance of the pH of the mixed liquor within a selected pH range, and wherein the method includes reducing the pH of the mixed liquor below 6, or maintaining the pH of the mixed liquor below 6 for a selected period of time, and wherein the pH adjustment of the mixed liquor to below 6 or the maintenance of the pH of the mixed liquor below 6 gives rise to an increase in chemical and/or thermal stability of the PHA in the biomass.
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| 28. |
- Zhang, Emma, 1985, et al.
(author)
-
Activation of municipal solid waste incineration ashes for green concrete
- 2020
-
In: IOP Conference Series: Earth and Environmental Science. - : IOP Publishing. - 1755-1307 .- 1755-1315. ; 588:4
-
Conference paper (peer-reviewed)abstract
- Due to the variable characteristics of municipal solid waste incineration (MSWI) ashes and the lack of coherent standards and regulations, a majority of MSWI ashes is landfilled currently. It is an urgent issue that the significant amount of residue MSWI ashes need to be better handled and reused as a renewable source. MSWI ashes have great potential to be utilized as a cementitious replacement material in concrete mixing, which is beneficial for both promoting MSWI ash reuse and reducing cement consumption. However, there are major challenges associated with MSWI ash reuse, including the presence of lack of efficient approach to restore the reactivity of MSWI ashes as a binding agent, because such ashes are usually low in reactivity or even inert. This study aims to develop an effective and reliable activation method to enable the pozzolanic and hydraulic properties of MSWI ashes. A novel activation methodology by means of physiochemical treatments, including particle size reduction and high pH activator was proposed to increase the reactivity of such bottom ashes. A rapid test method, namely solution test, was developed to test the potential reactivity after the activation. Thermogravimetric analysis (TGA) and ion chromatography (IC) were employed to evaluate the degree of reactivity. The results showed that the physicochemical treatment can indeed increase the reactivity of MSWI ashes. Compared to the existing test protocols using normal activator the new solution test can more effectively examine the latent pozzolanic activities of MSWI ashes. The successful application of the proposed activation methodology together with the developed solution test could turn those “inert or low reactivity” to-be-landfilled ashes into an active binding agent as a cement replacement material, which would contribute greatly to recycle and reuse of waste materials and reduce CO2 emission.
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| 29. |
- Apelgren, Peter, et al.
(author)
-
Chondrocytes and stem cells in 3D-bioprinted structures create human cartilage in vivo.
- 2017
-
In: PloS one. - : Public Library of Science (PLoS). - 1932-6203. ; 12:12
-
Journal article (peer-reviewed)abstract
- Cartilage repair and replacement is a major challenge in plastic reconstructive surgery. The development of a process capable of creating a patient-specific cartilage framework would be a major breakthrough. Here, we described methods for creating human cartilage in vivo and quantitatively assessing the proliferative capacity and cartilage-formation ability in mono- and co-cultures of human chondrocytes and human mesenchymal stem cells in a three-dimensional (3D)-bioprinted hydrogel scaffold. The 3D-bioprinted constructs (5 × 5 × 1.2 mm) were produced using nanofibrillated cellulose and alginate in combination with human chondrocytes and human mesenchymal stem cells using a 3D-extrusion bioprinter. Immediately following bioprinting, the constructs were implanted subcutaneously on the back of 48 nude mice and explanted after 30 and 60 days, respectively, for morphological and immunohistochemical examination. During explantation, the constructs were easy to handle, and the majority had retained their macroscopic grid appearance. Constructs consisting of human nasal chondrocytes showed good proliferation ability, with 17.2% of the surface areas covered with proliferating chondrocytes after 60 days. In constructs comprising a mixture of chondrocytes and stem cells, an additional proliferative effect was observed involving chondrocyte production of glycosaminoglycans and type 2 collagen. This clinically highly relevant study revealed 3D bioprinting as a promising technology for the creation of human cartilage.
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| 30. |
- Apelgren, Peter, et al.
(author)
-
In Vivo Human Cartilage Formation in Three-Dimensional Bioprinted Constructs with a Novel Bacterial Nanocellulose Bioink
- 2019
-
In: Acs Biomaterials Science & Engineering. - : American Chemical Society (ACS). - 2373-9878. ; 5:5, s. 2482-2490
-
Journal article (peer-reviewed)abstract
- Bacterial nanocellulose (BNC) is a 3D network of nanofibrils exhibiting excellent biocompatibility. Here, we present the aqueous counter collision (ACC) method of BNC disassembly to create bioink with suitable properties for cartilage-specific 3D-bioprinting. BNC was disentangled by ACC, and fibril characteristics were analyzed. Bioink printing fidelity and shear-thinning properties were evaluated. Cell-laden bioprinted grid constructs (5 X 5 X 1 mm(3)) containing human nasal chondrocytes (10 M mL(-1)) were implanted in nude mice and explanted after 30 and 60 days. Both ACC and hydrolysis resulted in significantly reduced fiber lengths, with ACC resulting in longer fibrils and fewer negative charges relative to hydrolysis. Moreover, ACC-BNC bioink showed outstanding printability, postprinting mechanical stability, and structural integrity. In vivo, cell-laden structures were rapidly integrated, maintained structural integrity, and showed chondrocyte proliferation, with 32.8 +/- 13.8 cells per mm(2) observed after 30 days and 85.6 +/- 30.0 cells per mm(2) at day 60 (p = 0.002). Furthermore, a full-thickness skin graft was attached and integrated completely on top of the 3D-bioprinted construct. The novel ACC disentanglement technique makes BNC biomaterial highly suitable for 3D-bioprinting and clinical translation, suggesting cell-laden 3D-bioprinted ACC-BNC as a promising solution for cartilage repair.
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| 31. |
- Chudinova, Ekaterina, et al.
(author)
-
Additive manufactured Ti6Al4V scaffolds with the RF-magnetron sputter deposited hydroxyapatite coating
- 2016
-
In: Journal of Physics: Conference Series. - : Institute of Physics Publishing (IOPP). - 1742-6588 .- 1742-6596.
-
Conference paper (peer-reviewed)abstract
- Present paper reports on the results of surface modification of the additively manufactured porous Ti6Al4V scaffolds. Radio frequency (RF) magnetron sputtering was used to modify the surface of the alloy via deposition of the biocompatible hydroxyapatite (HA) coating. The surface morphology, chemical and phase composition of the HA-coated alloy were studied. It was revealed that RF magnetron sputtering allows preparing a homogeneous HA coating onto the entire surface of scaffolds.
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| 32. |
- Chudinova, Ekaterina, et al.
(author)
-
In Vitro Assessment of Hydroxyapatite Coating on the Surface of Additive Manufactured Ti6Al4V Scaffolds
- 2017
-
In: Materials Science Forum. - Switzerland : Trans Tech Publications Inc.. - 0255-5476 .- 1662-9752. ; 879, s. 2444-2449
-
Journal article (peer-reviewed)abstract
- Custom orthopedic and dental implants may be fabricated by additive manufacturing (AM), for example using electron beam melting technology. This study is focused on the modification of the surface of Ti6Al4V alloy coin-like scaffolds fabricated via AM technology (EBM®) by radio frequency (RF) magnetron sputter deposition of hydroxyapatite (HA) coating. The scaffolds with HA coating were characterized by Scanning Electron microscopy, X-ray diffraction. HA coating showed a nanocrystalline structure with the crystallites of an average size of 32±9 nm. The ability of the surface to support adhesion and the proliferation of human mesenchymal stem cells was studied using biological short-term tests in vitro. In according to in vitro assessment, thin HA coating stimulated the attachment and proliferation of cells. Human mesenchymal stem cells cultured on the HA-coated scaffold also formed mineralized nodules.
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| 33. |
- Jocic, Simonne, et al.
(author)
-
Fabrication of user-friendly and biomimetic 1,1′-carbonyldiimidazole cross-linked gelatin/agar microfluidic devices
- 2017
-
In: Materials Science and Engineering C. - : Elsevier BV. - 0928-4931 .- 1873-0191. ; 76, s. 1175-1180
-
Journal article (peer-reviewed)abstract
- We have developed a straightforward technique for fabricating user-friendly and biomimetic microfluidic devices out of a gelatin/agar gel cross-linked with 1,1′-carbonyldiimidazole. The fabrication procedure requires only inexpensive starting materials such as glass capillaries and wires to mold 3D cylindrical channels into the gel with the possibility of achieving channel diameters of 375 μm and 1000 μm. We demonstrate that the channel absent of gel injury can retain fluid within its dimensions for at least 7 h. We also show that the device material does not autofluoresce nor provide hindrances with fluorescent imaging. A discussion of the chemical linkage identities of cross-linked gelatin/agar is included via ATR-FTIR studies. Crosslinking of the gelatin/agar is further confirmed by the lack of a gel to sol transition at physiological temperature as assessed by DSC measurements. SEM micrographs that demonstrate the 100 nm mean pore width of the cross-linked gelatin/agar are provided. This device is considered biomimetic because it represents components present in the natural extracellular matrix such as collagen and proteoglycans in the form of cross-linked gelatin/agar.
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| 34. |
- Larsson, Karl-Johan, 1985, et al.
(author)
-
Influences of human thorax variability on population rib fracture risk prediction using human body models
- 2023
-
In: Frontiers in Bioengineering and Biotechnology. - : Frontiers Media SA. - 2296-4185. ; 11
-
Journal article (peer-reviewed)abstract
- Rib fractures remain a common injury for vehicle occupants in crashes. The risk of a human sustaining rib fractures from thorax loading is highly variable, potentially due to a variability in individual factors such as material properties and geometry of the ribs and ribcage. Human body models (HBMs) with a detailed ribcage can be used as occupant substitutes to aid in the prediction of rib injury risk at the tissue level in crash analysis. To improve this capability, model parametrization can be used to represent human variability in simulation studies. The aim of this study was to identify the variations in the physical properties of the human thorax that have the most influence on rib fracture risk for the population of vehicle occupants. A total of 15 different geometrical and material factors, sourced from published literature, were varied in a parametrized SAFER HBM. Parametric sensitivity analyses were conducted for two crash configurations, frontal and near-side impacts. The results show that variability in rib cortical bone thickness, rib cortical bone material properties, and rib cross-sectional width had the greatest influence on the risk for an occupant to sustain two or more fractured ribs in both impacts. Therefore, it is recommended that these three parameters be included in rib fracture risk analysis with HBMs for the population of vehicle occupants.
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| 35. |
- Singh, Shikha, et al.
(author)
-
Orientation of Polylactic Acid–Chitin Nanocomposite Films via Combined Calendering and Uniaxial Drawing: Effect on Structure, Mechanical, and Thermal Properties
- 2021
-
In: Nanomaterials. - : MDPI. - 2079-4991. ; 11:12
-
Journal article (peer-reviewed)abstract
- The orientation of polymer composites is one way to increase the mechanical properties of the material in a desired direction. In this study, the aim was to orient chitin nanocrystal (ChNC)-reinforced poly(lactic acid) (PLA) nanocomposites by combining two techniques: calendering and solid-state drawing. The effect of orientation on thermal properties, crystallinity, degree of orientation, mechanical properties and microstructure was studied. The orientation affected the thermal and structural behavior of the nanocomposites. The degree of crystallinity increased from 8% for the isotropic compression-molded films to 53% for the nanocomposites drawn with the highest draw ratio. The wide-angle X-ray scattering results confirmed an orientation factor of 0.9 for the solid-state drawn nanocomposites. The mechanical properties of the oriented nanocomposite films were significantly improved by the orientation, and the pre-orientation achieved by film calendering showed very positive effects on solid-state drawn nanocomposites: The highest mechanical properties were achieved for pre-oriented nanocomposites. The stiffness increased from 2.3 to 4 GPa, the strength from 37 to 170 MPa, the elongation at break from 3 to 75%, and the work of fracture from 1 to 96 MJ/m3. This study demonstrates that the pre-orientation has positive effect on the orientation of the nanocomposites structure and that it is an extremely efficient means to produce films with high strength and toughness.
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| 36. |
- Sämfors, Sanna, 1987, et al.
(author)
-
Biofabrication of bacterial nanocellulose scaffolds with complex vascular structure
- 2019
-
In: Biofabrication. - : IOP Publishing. - 1758-5082 .- 1758-5090. ; 11:4
-
Journal article (peer-reviewed)abstract
- Bacterial nanocellulose (BNC) has proven to be an effective hydrogel-like material for different tissue engineering applications due to its biocompatibility and good mechanical properties. However, as for all biomaterials, in vitro biosynthesis of large tissue constructs remains challenging due to insufficient oxygen and nutrient transport in engineered scaffold-cell matrices. In this study we designed, biofabricated and evaluated bacterial nanocellulose scaffolds with a complex vascular mimetic lumen structure. As a first step a method for creating straight channeled structures within a bacterial nanocellulose scaffold was developed and evaluated by culturing of Human Umbilical Vein Endothelial Cells (HUVECs). In a second step, more complex structures within the scaffolds were produced utilizing a 3D printer. A print mimicking a vascular tree acted as a sacrificial template to produce a network within the nanoporous bacterial nanocellulose scaffolds that could be lined with endothelial cells. In a last step, a method to produce large constructs with interconnected macro porosity and vascular like lumen structure was developed. In this process patient data from x-ray computed tomography scans was used to create a mold for casting a full-sized kidney construct. By showing that the 3D printing technology can be combined with BNC biosynthesis we hope to widen the opportunities of 3D printing, while also enabling the production of BNC scaffolds constructs with tailored vascular architectures and properties.
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| 37. |
- Ahlqvist, Josefin, et al.
(author)
-
DNA digestion and formation of DNA-network structures with Holliday junction-resolving enzyme Hjc_15-6 in conjunction with polymerase reactions
-
In: Journal of Biotechnology. - 1873-4863.
-
Journal article (peer-reviewed)abstract
- The recently identified novel Holliday junction-resolving enzyme, termed Hjc_15-6, activity investigation results imply DNA cleavage by Hjc_15-6 in a manner that potentially enhances the molecular self-assembly that may be exploited for creating DNA-networks and nanostructures. The study also demonstrates Pwo DNA polymerase acting in combination with Hjc_15-6 capability to produce large amounts of DNA that transforms into large DNA-network structures even without DNA template and primers. Furthermore, it is demonstrated that Hjc_15-6 prefers Holliday junction oligonucleotides as compared to Y-shaped oligonucleotides as well as efficiently cleaves typical branched products from isothermal DNA amplification of both linear and circular DNA templates amplified by phi29-like DNA polymerase. The assembly of large DNA network structures was observed in real time, by transmission electron microscopy, on negative stained grids that were freshly prepared, and also on the same grids after incubation for 4 days under constant cooling. Hence, Hjc_15-6 is a promising molecular tool for efficient production of various DNA origamis that may be implemented for a wide range of applications such as within medical biomaterials, catalytic materials, molecular devices and biosensors.
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| 38. |
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| 39. |
- Eivazihollagh, Alireza, et al.
(author)
-
On chelating surfactants : Molecular perspectives and application prospects
- 2019
-
In: Journal of Molecular Liquids. - : Elsevier BV. - 0167-7322 .- 1873-3166. ; 278, s. 688-705
-
Journal article (peer-reviewed)abstract
- Chelating agents, molecules that very strongly coordinates certain metal ions, are used industrially as well as in consumer products to minimize disturbances and increase performance of reactions and applications. The widely used sequestering agents, nitrilotriacetic acid (NTA), ethylenediaminetetraacetic acid (EDTA) and diethylenetriaminepentaacetic acid (DTPA) belong to this branch of readily water-soluble compounds. When these chemical structures also have hydrophobic parts, they are prone to adsorb at air-water interfaces and to self-assemble. Such bifunctional molecules can be called chelating surfactants and will have more extended utilization prospects than common chelating agents or ordinary ionic surfactants. The present review attempts to highlight the fundamental behavior of chelating surfactants in solution and at interfaces, and their very specific interactions with metal ions. Methods to recover chelating surfactants from metal chelates are also described. Moreover, utilization of chelating surfactants in applications for metal removal in environmental engineering and mineral processing, as well as for metal control in the fields of biology, chemistry and physics, is exemplified and discussed.
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| 40. |
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| 41. |
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| 42. |
- Parker, Daniela, et al.
(author)
-
Biohybrid plants with electronic roots via in vivo polymerization of conjugated oligomers
- 2021
-
In: Materials Horizons. - : Royal Society of Chemistry. - 2051-6347 .- 2051-6355. ; 8:12, s. 3295-3305
-
Journal article (peer-reviewed)abstract
- Plant processes, ranging from photosynthesis through production of biomaterials to environmental sensing and adaptation, can be used in technology via integration of functional materials and devices. Previously, plants with integrated organic electronic devices and circuits distributed in their vascular tissue and organs have been demonstrated. To circumvent biological barriers, and thereby access the internal tissue, plant cuttings were used, which resulted in biohybrids with limited lifetime and use. Here, we report intact plants with electronic functionality that continue to grow and develop enabling plant-biohybrid systems that fully maintain their biological processes. The biocatalytic machinery of the plant cell wall was leveraged to seamlessly integrate conductors with mixed ionic-electronic conductivity along the root system of the plants. Cell wall peroxidases catalyzed ETE-S polymerization while the plant tissue served as the template, organizing the polymer in a favorable manner. The conductivity of the resulting p(ETE-S) roots reached the order of 10 S cm(-1) and remained stable over the course of 4 weeks while the roots continued to grow. The p(ETE-S) roots were used to build supercapacitors that outperform previous plant-biohybrid charge storage demonstrations. Plants were not affected by the electronic functionalization but adapted to this new hybrid state by developing a more complex root system. Biohybrid plants with electronic roots pave the way for autonomous systems with potential applications in energy, sensing and robotics.
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| 43. |
- Raji, Olanrewaju, et al.
(author)
-
The coordinated action of glucuronoyl esterase and α-glucuronidase promotes the disassembly of lignin–carbohydrate complexes
- 2021
-
In: FEBS Letters. - : Wiley. - 1873-3468 .- 0014-5793. ; 595:3, s. 351-359
-
Journal article (peer-reviewed)abstract
- Glucuronoxylans represent a significant fraction of woody biomass, and its decomposition is complicated by the presence of lignin–carbohydrate complexes (LCCs). Herein, LCCs from birchwood were used to investigate the potential coordinated action of a glucuronoyl esterase (TtCE15A) and two α-glucuronidases (SdeAgu115A and AxyAgu115A). When supplementing α-glucuronidase with equimolar quantities of TtCE15A, total MeGlcpA released after 72 h by SdeAgu115A and AxyAgu115A increased from 52% to 67%, and 61% to 95%, respectively. Based on the combined TtCE15A and AxyAgu115A activities, ~ 34% of MeGlcpA in the extracted birchwood glucuronoxylan was occupied as LCCs. Notably, insoluble LCC fractions reduced soluble α-glucuronidase concentrations by up to 70%, whereas reduction in soluble TtCE15A was less than 30%, indicating different tendencies to adsorb onto the LCC substrate.
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| 44. |
- Seveso, Andrea, 1992, et al.
(author)
-
Enzyme discovery and structure-function investigation of carbohydrate-active enzymes
- 2019
-
Conference paper (other academic/artistic)abstract
- The plant cell wall is the main component of wood, and it has a highly complex structure. In nature, microorganisms can essentially break down all of its parts, and their enzymes can be used for catalyzing specific reaction to remodel and modify wood-derived individual polysaccharides and complex fibers. There are still significant knowledge gaps regarding the interaction with the complex cell wall matrix on the molecular level. Further research on carbohydrate-active enzymes is hence needed, with a particular focus on enzyme active on hemicelluloses and on covalent bonds between lignin and polysaccharides. Investigating proteins of unknown function is also interesting, as they may be enzymes possessing novel activities towards the polymers of the cell wall.
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| 45. |
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| 46. |
- Stépán, Agnes, 1985, et al.
(author)
-
Enzymatic Transformation of Hemicelluloses to Bioplastics
- 2012
-
In: 243rd ACS National Meeting, 25-29 March 2012, San Diego, CA, USA.
-
Conference paper (other academic/artistic)abstract
- Hemicelluloses being the second most abundant biopolymer on Earth are getting more attention in the recent years for having a great potential as a renewable source for materials, fine chemicals and fuels. The focus of this study is to modify molecular architecture of spruce arabinoglucuronoxylan (AGX) and to gain better understanding of structure-material properties relationships. Chemical acetylation and gradient debranching of arabinoxylan has been carried out and material properties have been evaluated. The recent work is more focused on enzymatic acetylation and acylation. Most of our enzymatic modifications are based on enzymes with a proven record in biocatalytic reactions. In parallel, we target the use of more specific acting enzymes as well. These enzymes are commercially not available yet, so this part includes enzyme cloning and production. The desired product is a thermoplastic biomaterial suitable for packaging or as binder / matrix in a biocomposite.
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| 47. |
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| 48. |
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| 49. |
- Abitbol, Tiffany, et al.
(author)
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Cellulose nanocrystal/low methoxyl pectin gels produced by internal ionotropic gelation.
- 2021
-
In: Carbohydrate Polymers. - : Elsevier BV. - 0144-8617 .- 1879-1344. ; 260
-
Journal article (peer-reviewed)abstract
- The biotechnological applications of cellulose nanocrystals (CNCs) continue to grow due to their sustainable nature, impressive mechanical, rheological, and emulsifying properties, upscaled production capacity, and compatibility with other materials, such as protein and polysaccharides. In this study, hydrogels from CNCs and pectin, a plant cell wall polysaccharide broadly used in food and pharma, were produced by calcium ion-mediated internal ionotropic gelation (IG). In the absence of pectin, a minimum of 4 wt% CNC was needed to produce self-supporting gels by internal IG, whereas the addition of pectin at 0.5 wt% enabled hydrogel formation at CNC contents as low as 0.5 wt%. Experimental data indicate that CNCs and pectin interact to give robust and self-supporting hydrogels at solid contents below 2.5 %. Potential applications of these gels could be as carriers for controlled release, scaffolds for cell growth, or wherever else distinct and porous network morphologies are required.
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| 50. |
- Adu, Cynthia, et al.
(author)
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Properties of cellulose nanofibre networks prepared from never-dried and dried paper mill sludge
- 2018
-
In: Journal of Cleaner Production. - : Elsevier. - 0959-6526 .- 1879-1786. ; 197:1, s. 765-771
-
Journal article (peer-reviewed)abstract
- Paper mills yield large volumes of sludge materials which pose an environmental and economic challenge for disposal, despite the fact that they could be a valuable source for cellulose nanofibres (CNF) production. The aim of the study was to evaluate the production process and properties of CNF prepared by mechanical fibrillation of never-dried and dried paper mill sludge (PMS). Atomic force microscopy (AFM) showed that average diameters for both never-dried and dried paper sludge nanofibres (PSNF) were less than 50 nm. The never-dried and dried sludge nanofibres showed no statistical significant difference (p > 0.05) in strength 92 MPa, and 85 MPa and modulus 11 GPa and 10 GPa. The study concludes that paper mill sludge can be used in a dried state for CNF production to reduce transportation and storage challenges posed on industrial scale.
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