| 1. |
- Adu, Cynthia, et al.
(författare)
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Properties of cellulose nanofibre networks prepared from never-dried and dried paper mill sludge
- 2018
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Ingår i: Journal of Cleaner Production. - : Elsevier. - 0959-6526 .- 1879-1786. ; 197:1, s. 765-771
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Tidskriftsartikel (refereegranskat)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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| 2. |
- Aitomäki, Yvonne, et al.
(författare)
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Light scattering in cellulose nanofibre suspensions : Model and experiments
- 2016
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Ingår i: Computers in Chemistry Proceeding from ACS National Meeting San Diego. - : American Chemical Society (ACS). ; , s. 122-
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Here light scattering theory is used to assess the size distribution in a suspension of cellulose as it is fibrillated from micro-scaled to nano-scaled fibres. A model based on Monte carlo simulations of the scattering of photons by different sizes of cellulose fibres was used to predict the UV-IF spectrum of the suspensions. Bleached cellulose hardwood pulp was tested and compared to the visually transparent tempo-oxidised hardwood cellulose nanofibres (CNF) suspension. The theoretical results show that different diameter size classes exhibit very different scattering patterns. These classes could be identified in the experimental results and used to establish the size class dominating the suspension. A comparison to AFM/microscope size distribution was made and the results indicated that using the UV-IF light scattering spectrum maybe more reliable that size distribution measurement using AFM and microscopy on dried CNF samples. The UV-IF spectrum measurement combined with the theoretical prediction can be used even at this initial stage of development of this model to assess the degree of fibrillation when processing CNF.
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| 3. |
- Antlauf, Mathis, et al.
(författare)
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Thermal Conductivity of Cellulose Fibers in Different Size Scales and Densities
- 2021
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Ingår i: Biomacromolecules. - : American Chemical Society (ACS). - 1525-7797 .- 1526-4602. ; 22:9, s. 3800-3809
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Tidskriftsartikel (refereegranskat)abstract
- Considering the growing use of cellulose in various applications, knowledge and understanding of its physical properties become increasingly important. Thermal conductivity is a key property, but its variation with porosity and density is unknown, and it is not known if such a variation is affected by fiber size and temperature. Here, we determine the relationships by measurements of the thermal conductivity of cellulose fibers (CFs) and cellulose nanofibers (CNFs) derived from commercial birch pulp as a function of pressure and temperature. The results show that the thermal conductivity varies relatively weakly with density (ρsample = 1340–1560 kg m–3) and that its temperature dependence is independent of density, porosity, and fiber size for temperatures in the range 80–380 K. The universal temperature and density dependencies of the thermal conductivity of a random network of CNFs are described by a third-order polynomial function (SI-units): κCNF = (0.0787 + 2.73 × 10–3·T – 7.6749 × 10–6·T2 + 8.4637 × 10–9·T3)·(ρsample/ρ0)2, where ρ0 = 1340 kg m–3 and κCF = 1.065·κCNF. Despite a relatively high degree of crystallinity, both CF and CNF samples show amorphous-like thermal conductivity, that is, it increases with increasing temperature. This appears to be due to the nano-sized elementary fibrils of cellulose, which explains that the thermal conductivity of CNFs and CFs shows identical behavior and differs by only ca. 6%. The nano-sized fibrils effectively limit the phonon mean free path to a few nanometers for heat conduction across fibers, and it is only significantly longer for highly directed heat conduction along fibers. This feature of cellulose makes it easier to apply in applications that require low thermal conductivity combined with high strength; the weak density dependence of the thermal conductivity is a particularly useful property when the material is subjected to high loads. The results for thermal conductivity also suggest that the crystalline structures of cellulose remain stable up to at least 0.7 GPa.
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| 4. |
- Baş, Yağmur, et al.
(författare)
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Preparation and Characterization of Softwood and Hardwood Nanofibril Hydrogels: Toward Wound Dressing Applications
- 2023
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Ingår i: Biomacromolecules. - : American Chemical Society (ACS). - 1525-7797 .- 1526-4602. ; 24:12, s. 5605-5619
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Tidskriftsartikel (refereegranskat)abstract
- Hydrogels of cellulose nanofibrils (CNFs) are promising wound dressing candidates due to their biocompatibility, high water absorption, and transparency. Herein, two different commercially available wood species, softwood and hardwood, were subjected to TEMPO-mediated oxidation to proceed with delignification and oxidation in a one-pot process, and thereafter, nanofibrils were isolated using a high-pressure microfluidizer. Furthermore, transparent nanofibril hydrogel networks were prepared by vacuum filtration. Nanofibril properties and network performance correlated with oxidation were investigated and compared with commercially available TEMPO-oxidized pulp nanofibrils and their networks. Softwood nanofibril hydrogel networks exhibited the best mechanical properties, and in vitro toxicological risk assessment showed no detrimental effect for any of the studied hydrogels on human fibroblast or keratinocyte cells. This study demonstrates a straightforward processing route for direct oxidation of different wood species to obtain nanofibril hydrogels for potential use as wound dressings, with softwood having the most potential.
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| 5. |
- Berglund, Andreas, et al.
(författare)
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15 koncept för bättre ergonomi : Inom äldreomsorg, fysioterapi, däckmontering och varuhantering
- 2015
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Rapport (populärvet., debatt m.m.)abstract
- Den här boken är resultatet av en kurs i ergonomi vid Teknisk design, Luleå tekniska universitet, våren 2015. 15 kursdeltagare har under 10 veckor använt designmetodik och ergonomiska teorier och metoder för att utveckla 15 konceptuella förbättringsförslag baserade på de 4 undersökta kontexterna äldreomsorg, fysioterapi, däckmontering och varuhantering. Fokus för ergonomi inom området teknisk design är att se till att all design, oavsett vilket system det avser, kompletterar människans styrkor och förmågor. Vi ska kort och gott se till att arbetsuppgifter, utrustning, apparater, processer, miljöer och organisationer utformas med människan som utgångspunkt, istället för att tvinga människan att anpassa sig med olika former av överbelastning som möjlig påföljd. För att uppnå detta behöver vi förstå och designa för den variabilitet som är representerad bland oss människor: vi är olika, har olika åldrar, storlek, styrka, kognitiv förmåga, erfarenheter, förväntningar och mål. Att tillämpa ergonomi betyder att studera hur människor interagerar med produkter, processer, miljöer och system för att förbättra dem, dvs. göra dem enklare, säkrare, bekvämare och effektivare att använda. För att kunna göra det behöver vi kunskap om människans förutsättningar och behov. Teknisk design med utgångspunkt och mål i god ergonomi innebär att exempelvis: Att designa produkter och utrustning som är enkla och tillförlitliga att använda med utgångspunkt i kunskap om kognitiv ergonomi, antropometri och belastningsergonomiska och biomekaniska analyserAtt designa säkra och effektiva tillverkningsprocesser med utgångspunkt i kunskap om kognitiv ergonomi och belastningsergonomiska analyserAtt designa organisationer utifrån kunskap om arbetslivsfysiologi och organisationsergonomiAtt designa arbetsuppgifter utifrån kunskap om kognitiv ergonomi, biomekanik och belastningsergonomiska analyserAtt designa enkla och användarvänliga gränssnitt med utgångspunkt i kognitiv ergonomiErgonomisk anpassning av en produkt eller en arbetsmiljö kan exempelvis handla om att se till att människan inte använder kroppen felaktigt. Det kan handla om fysisk belastning när en uppgift utförs, såväl som sensorisk input från olika system eller psykosocial belastning i form av stress. Det handlar om att utveckla kunskaper om människans begränsningar och förmågor, vilket ger bättre förutsättningar att bidra till användarvänliga lösningar. Det i sin tur bidrar till säkerhet och användarvänlighet och i slutändan att alla produkter, system och miljöer i vår omvärld fungerar väl för människan – det är hållbar utveckling om något. I kursen Ergonomi 2 vid civilingenjörsutbildningen Teknisk design, Luleå tekniska universitet, ingår en projektuppgift. Den syftar till att få fördjupad förståelse inom ergonomi genom att tillämpa kunskap och metoder i ett designprojekt för en verklig situation. Våren 2015 omfattade projektuppgiften att enanalys av valfri kontext, med syfte att förstå problem och utmaningar i den miljö, det sammanhang, den situation och för de personer som var berörda. Inledningsvis arbetade kursdeltagarna i grupper bestående av 3-4 personer, för att sedan gå in i en konceptutvecklingsfas individuellt. Det innebar att kursdeltagarna kunde genomföra ergonomiska analyser gemensamt och sedan utveckla konceptuella lösningar på egen hand. Det resulterade i att kursdeltagarna utvecklade tämligen olika lösningar, även om de haft en gemensam utgångspunkt. Bokens kapitel omfattar en beskrivning av respektive kontext följt av de konceptförslag som kursdeltagarna utvecklade. Som lärare är det alltid extra roligt när kursdeltagare är motiverade och engagerade inför projektuppgifter. Vår förhoppning är att det engagemanget ska framgå på följande sidor och att koncepten ska ge inspiration till att förbättra ergonomin i våra vardagsliv. Åsa Wikberg Nilsson, Therese Öhrling, Lars Sundström, Agneta Larsson och Ulrik RöijezonTeknisk design Luleå tekniska universitet, Augusti 2015
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| 6. |
- Berglund, Hilda-Linn, et al.
(författare)
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Sampling of flower-visiting insects : Poor correspondence between the catches of colour pan-trap and sweep netting
- 2019
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Ingår i: European Journal of Entomology. - Ceske Budejovice, Czech Republic : Akademie Ved Ceske Republiky * Entomologicky Ustav. - 1210-5759 .- 1802-8829. ; 116, s. 425-431
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Tidskriftsartikel (refereegranskat)abstract
- Pollinating insects are important and therefore, it is important to be able to assess and monitor changes in their abundance. Consequently, it is essential that the methods used to collect data have some level of precision and are accurate. In the present study, two commonly used methods: colour pan-traps and sweep netting along transects, were compared. A total of 1775 specimens of 120 species of four insect families were caught in twelve clear-cuts in southern Sweden. Overall, Lepturinae (Cerambycidae; 5 species) and Cetoniidae (Scarabaeidae; 2) were trapped in larger numbers by pan-traps and Syrphidae (62) and Apoidea, both social (10) and solitary (41), by sweep netting. The catches of none of the above groups of insects by the two methods were correlated. These results show that the composition of catches of the two methods are very different, which has implications when choosing a method for sampling or monitoring and comparing and analysing published data.
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| 7. |
- Berglund, Lisa, et al.
(författare)
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A genecentric Human Protein Atlas for expression profiles based on antibodies
- 2008
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Ingår i: Molecular & Cellular Proteomics. - 1535-9476 .- 1535-9484. ; 7:10, s. 2019-2027
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Forskningsöversikt (refereegranskat)abstract
- An attractive path forward in proteomics is to experimentally annotate the human protein complement of the genome in a genecentric manner. Using antibodies, it might be possible to design protein-specific probes for a representative protein from every protein-coding gene and to subsequently use the antibodies for systematical analysis of cellular distribution and subcellular localization of proteins in normal and disease tissues. A new version (4.0) of the Human Protein Atlas has been developed in a genecentric manner with the inclusion of all human genes and splice variants predicted from genome efforts together with a visualization of each protein with characteristics such as predicted membrane regions, signal peptide, and protein domains and new plots showing the uniqueness (sequence similarity) of every fraction of each protein toward all other human proteins. The new version is based on tissue profiles generated from 6120 antibodies with more than five million immunohistochemistry-based images covering 5067 human genes, corresponding to approximately 25% of the human genome. Version 4.0 includes a putative list of members in various protein classes, both functional classes, such as kinases, transcription factors, G-protein-coupled receptors, etc., and project-related classes, such as candidate genes for cancer or cardiovascular diseases. The exact antigen sequence for the internally generated antibodies has also been released together with a visualization of the application-specific validation performed for each antibody, including a protein array assay, Western blot analysis, immunohistochemistry, and, for a large fraction, immunofluorescence-based confocal microscopy. New search functionalities have been added to allow complex queries regarding protein expression profiles, protein classes, and chromosome location. The new version of the protein atlas thus is a resource for many areas of biomedical research, including protein science and biomarker discovery.
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| 8. |
- Berglund, Lisa, et al.
(författare)
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A whole-genome bioinformatics approach to selection of antigens for systematic antibody generation
- 2008
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Ingår i: Proteomics. - : Wiley. - 1615-9853 .- 1615-9861. ; 8:14, s. 2832-2839
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Tidskriftsartikel (refereegranskat)abstract
- Here, we present an antigen selection strategy based on a whole-genome bioinformatics approach, which is facilitated by an interactive visualization tool displaying protein features from both public resources and in-house generated data. The web-based bioinformatics platform has been designed for selection of multiple, non-overlapping recombinant protein epitope signature tags by display of predicted information relevant for antigens, including domain- and epitope sized sequence similarities to other proteins, transmembrane regions and signal peptides. The visualization tool also displays shared and exclusive protein regions for genes with multiple splice variants. A genome-wide analysis demonstrates that antigens for approximately 80% of the human protein-coding genes can be selected with this strategy.
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| 9. |
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| 10. |
- Berglund, Linn
(författare)
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From bio-based residues to nanofibers using mechanical fibrillation for functional biomaterials
- 2019
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Bio-based resource utilization in different forms has been driven by societal, industrial and academic research interests towards the development of “green”, sustainable materials from renewable sources. Within this context, exploiting biomass from different industrial residues is further advantageous from an environmental and economic point of view, leading to minimization of residues by means of waste treatment and to the development of high-addedvalue- products. Breaking down the cell wall structure to its smallest structural components is one means of turning bio-based residues into high-value products, leaving us with nanofibers. The aim of this work has been to understand how these nanofibers can be liberated from various cellulosic sources using mechanical fibrillation and how they can be assembled into functional hydrogels.The production of bio-based nanofibers as a sustainable bio-based material is in the early stages of commercialization and considerable research has been devoted to explore different methods of reaching nanoscale. However, the extraction process by chemical and/or mechanical means is still associated with a relatively high energy demand and/or cost. These are key obstacles for use of the material in a wide range of applications. Another challenge is that methods to characterize nanofiber dimensions are still being developed, with few options available as online measurements for assessing the degree of fibrillation. Allowing for assessment during the fibrillation process would enable not only optimization towards a more energy efficient fibrillation, but also matching of the nanofiber quality to its intended function, since different applications will require widely different nanofiber qualities. Energy-efficient fibrillation and scalability from industrial residues were explored using upscalable ultrafine grinding processes.Nanofibers from various industrial bio-residues and wood were prepared and characterized, including the development of a method for evaluation of the fibrillation process online via viscosity measurements as an indication of the degree of fibrillation down to nanoscale. Furthermore, the correlation of viscosity to that of the strength of the nanopapers (dried fiber networks) was evaluated for the different raw materials.Switchable ionic liquids (SIL) were tested as a green pretreatment for delignification, without bleaching of wood prior to fibrillation, with the aim to preserve the low environmental impact that the raw material source offers.In order to employ the hydrophilic nature and strong network formation ability of the fibrillated nanofibers, they were utilized in the preparation of functional biomaterials in the form of hydrogels. Firstly, brewer’s spent grain nanofibers were used to promote and reinforce hydrogel formation of lignin-containing arabinoxylan, resulting in a hydrogel completely derived from barley residues. In addition, alginate-rich seaweed nanofibers from the stipe (stem-like part of the seaweed) were used directly after fibrillation as an ink and hydrogels were formed via 3D printing.
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