| 11. |
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| 12. |
- Frostell, Claes, et al.
(author)
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Tracheal implants revisited
- 2017
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In: The Lancet. - : ELSEVIER SCIENCE INC. - 0140-6736 .- 1474-547X. ; 389:10075, s. 1191-1191
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Journal article (peer-reviewed)
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| 13. |
- García-García, Daniel, et al.
(author)
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Reinforcing capability of cellulose nanocrystals obtained from pine cones in a biodegradable poly(3-hydroxybutyrate)/poly(ε-caprolactone) (PHB/PCL) thermoplastic blend
- 2018
-
In: European Polymer Journal. - : Elsevier. - 0014-3057 .- 1873-1945. ; 104, s. 10-18
-
Journal article (peer-reviewed)abstract
- In this work, different loads (3, 5 and 7 wt%) of pine cone cellulose nanocrystals (CNCs) were added to films ofpoly(3-hydroxybutyrate)/poly(ε-caprolactone) (PHB/PCL) blends with a composition of 75 wt% PHB and 25 wt% PCL (PHB75/PCL25). The films were obtained after solvent casting followed by melt compounding in anextruder and finally subjected to a thermocompression process. The influence of different CNCs loadings on themechanical, thermal, optical, wettability and disintegration in controlled compost properties of the PHB75/PCL25blend was discussed. Field emission scanning electron microscopy (FESEM) revealed the best dispersion of CNCson the polymeric matrix was at a load of 3 wt%. Over this loading, CNCs aggregates were formed enhancing thefilms fragilization due to stress concentration phenomena. However, the addition of CNCs improved the opticalproperties of the PHB75/PCL25films by increasing their transparency and accelerated the film disintegration incontrolled soil conditions. In general, the blend with 3 wt% CNCs offers the best balanced properties in terms ofmechanical, thermal, optical and wettability
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| 14. |
- Gil-Castell, O., et al.
(author)
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Effect of the dissolution time into an acid hydrolytic solvent to taylor electrospun nanofibrous polycaprolactone scaffolds
- 2017
-
In: European Polymer Journal. - : Elsevier. - 0014-3057 .- 1873-1945. ; 87, s. 174-187
-
Journal article (peer-reviewed)abstract
- The hydrolysis of the polycaprolactone (PCL) as a function of the dissolution time in a formic/acetic acid mixture was considered as a method for tailoring the morphology of nanofibrous PCL scaffolds. Hence, the aim of this research was to establish a correlation between the dissolution time of the polymer in the acid solvent with the physico-chemical properties of the electrospun nanofibrous scaffolds and their further service life behaviour. The physico-chemical properties of the scaffolds were assessed in terms of fibre morphology, molar mass and thermal behaviour. A reduction of the molar mass and the lamellar thickness as well as an increase of the crystallinity degree were observed as a function of dissolution time. Bead-free fibres were found after 24 and 48 h of dissolution time, with similar diameter distributions. The decrease of the fibre diameter distributions along with the apparition of beads was especially significant for scaffolds prepared after 72 h and 120 h of dissolution time in the acid mixture. The service life of the obtained devices was evaluated by means of in vitro validation under abiotic physiological conditions. All the scaffolds maintained the nanofibrous structure after 100 days of immersion in water and PBS. The molar mass was barely affected and the crystallinity degree and the lamellar thickness increased along immersion, preventing scaffolds from degradation. Scaffolds prepared after 24 h and 48 h kept their fibre diameters, whereas those prepared after 72 h and 120 h showed a significant reduction. This PCL tailoring procedure to obtain scaffolds that maintain the nanoscaled structure after such long in vitro evaluation will bring new opportunities in the design of long-term biomedical patches.
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| 15. |
- Gil-Castell, O., et al.
(author)
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Impact of hydrothermal ageing on the thermal stability, morphology and viscoelastic performance of PLA/sisal biocomposites
- 2016
-
In: Polymer degradation and stability. - : Elsevier. - 0141-3910 .- 1873-2321.
-
Journal article (peer-reviewed)abstract
- The influence of the combined exposure to water and temperature on the behaviour of polylactide/sisal biocomposites coupled with maleic acid anhydride was assessed through accelerated hydrothermal ageing. The biocomposites were immersed in water at temperatures from 65 to 85 °C, between the glass transition and cold crystallisation of the PLA matrix. The results showed that the most influent factor for water absorption was the percentage of fibres, followed by the presence of coupling agent, whereas the effect of the temperature was not significant. Deep assessment was devoted to biocomposites subjected to hydrothermal ageing at 85 °C, since it represents the extreme degrading condition. The morphology and crystallinity of the biocomposites were evaluated by means of X-Ray diffraction (XRD) and field emission scanning electron microscopy (FE-SEM). The viscoelastic and thermal performance were assessed by means of dynamic mechanic thermal analysis (DMTA) and thermogravimetry (TGA). The presence of sisal generally diminished the thermal stability of the biocomposites, which was mitigated by the addition of the coupling agent. After composite preparation, the effectiveness of the sisal fibre was improved by the crystallisation of PLA around sisal, which increased the storage modulus and reduced the dampening factor. The presence of the coupling agent strengthened this effect. After hydrothermal ageing, crystallisation was promoted in all biocomposites therefore showing more fragile behaviour evidencing pores and cracks. However, the addition of coupling agent in the formulation of biocomposites contributed in all cases to minimise the effects of hydrothermal ageing.
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| 16. |
- Hallberg, Elisabet, et al.
(author)
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Miljöbedömning av matavfallsemballage - Livscykelanalys av olika påsalternativ
- 2018
-
Reports (other academic/artistic)abstract
- Matavfall används ofta i Sverige för att producera biogödsel och biogas. Olika typer av matavfallsemballage (matavfallspåsar) kan användas för insamling av matavfall, t ex: plastpåsar av polyeten (fossil- eller bio-baserade), påsar från material baserade på majs- eller potatisstärkelse, papperspåsar. Alternativen har olika egenskaper och olika fördelar och nackdelar. Många kommuner i Sverige ställer krav på en specifik typ av emballage som ska användas. Idag finns det inga speciella krav för matavfallsemballage för insamling av matavfall i Uppsala kommun och hushållen väljer själva vilken typ av påse som används. Uppsala Vatten vill undersöka om det ur hållbarhetssynpunkt finns skäl att göra förändringar av dagens insamlingssystem. I den här studien gjordes en miljöutvärdering av olika typer av matavfallsemballage för insamling från hushåll. Projektets syfte var att adressera frågeställningen hur matavfallsemballage av olika material påverkar klimatprestandan för insamling och rötning av matavfall. Studien har, genom livscykelanalys (LCA), utforskat, utvärderat och dokumenterat klimatpåverkan från olika matavfallsemballage längs hela värdekedjan. Olika fördelar och nackdelar av materialval samt distribution av matavfallspåsar har också identifierats med hjälp av intervjuer med olika kommuner och företag i Sverige. De olika typerna av påsar för matavfallsemballage som har analyserats i den här studien är: fossil polyeten (PE), (bärkasse och avfallspåse på rulle); återvunnen PE (bärkasse och avfallspåse på rulle), bio-baserad PE (bärkasse och avfallspåse på rulle) samt kompostpåse (papper). En viktig del av en LCA-beräkning är att sätta systemgränser för vilka delar av livscykeln som beräkningen ska täcka in. Detta beror i sin tur på hur produkten används. I denna studie har t. ex. inte tillverkningen av råvara och påse tagits med i beräkningen för plastbärkassar p.g.a. att de främst är tillverkade för att användas till ett annat ändamål. För avfallspåse på rulle och kompostpåse av papper inkluderas däremot denna tillverkning eftersom dessa påsar enbart är avsedda att användas som matavfallsemballage. Resultaten visar att bärkassen av bio-baserad PE faller bäst ut ur klimatsynpunkt eftersom utsläppet av koldioxid (CO2) vid förbränning av bio-baserad PE är biogent och därmed enligt praxis inte räknas som ett bidrag till antropogen klimatpåverkan och dessutom exkluderas tillverkningen av råvara och påse. Det bör dock påpekas att valet av en bio-baserad PE bärkasse sällan är ett val man som konsument själv kan styra över eftersom tillgången regleras av butikernas val av material i påsar. Om man enbart jämför påsar som produceras för ändamålet att samla in matavfall (där ”uppströms produktion” inkluderas) är papperspåse (kompostpåse) bästa alternativet, och avfallspåse på rulle av fossil PE faller ut sämst ur klimatsynpunkt. Att kompostpåse av papper är det mest gynnsamma alternativet, beror främst på att utsläppet av koldioxid (CO2) vid förbränning av papper är biogent (analogt med fallet för bio-baserad PE). Påverkan från tillverkningen av råvaran (papper) samt påstillverkningen är också lägre för papperspåsen. Under studien observerades dock att resultaten är mycket känsliga för vissa osäkra parametrar, t ex: antagande om volym av matavfall per påse, mängder av producerad biogödsel och biogas samt biogödselkvalitet. Känslighetsanalyser visade att dessa parametrar kan påverka jämförelsen mellan påsarna och behöver därmed studeras mer för att säkerställa pålitliga resultat.
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| 17. |
- Högfeldt, Anna-Karin, et al.
(author)
-
Leading the teacher team - balancing between formal and informal power in program leadership
- 2018
-
In: Tertiary Education and Management. - : Springer Nature. - 1358-3883 .- 1573-1936. ; 24:1, s. 49-65
-
Journal article (peer-reviewed)abstract
- This continuous research within Nordic engineering institutions targets the contexts and possibilities for leadership among engineering education program directors. The IFP-model, developed based on analysis of interviews with program leaders in these institutions, visualizes the program director's informal and formal power. The model is presented as a tool for starting a shared discussion on the complexities of the leadership of engineering program development. The authors liken program development to hunting in teams. Each individual expert in the program is needed, and all experts will need to work and collaborate for the same target. This calls for strategic and long-term thinking of engineering education development. Institutions should support the development of both formal structures as well as informal leadership skills among their program directors, but never fall for the temptation to see the program director as the only actor on the stage.
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| 18. |
- Karlsson, Hannah, et al.
(author)
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Evaluation of Intracellular Signaling Downstream Chimeric Antigen Receptors
- 2015
-
In: PLOS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 10:12
-
Journal article (peer-reviewed)abstract
- CD19-targeting CAR T cells have shown potency in clinical trials targeting B cell leukemia. Although mainly second generation (2G) CARs carrying CD28 or 4-1BB have been investigated in patients, preclinical studies suggest that third generation (3G) CARs with both CD28 and 4-1BB have enhanced capacity. However, little is known about the intracellular signaling pathways downstream of CARs. In the present work, we have analyzed the signaling capacity post antigen stimulation in both 2G and 3G CARs. 3G CAR T cells expanded better than 2G CAR T cells upon repeated stimulation with IL-2 and autologous B cells. An antigen-driven accumulation of CAR+ cells was evident post antigen stimulation. The cytotoxicity of both 2G and 3G CAR T cells was maintained by repeated stimulation. The phosphorylation status of intracellular signaling proteins post antigen stimulation showed that 3G CAR T cells had a higher activation status than 2G. Several proteins involved in signaling downstream the TCR were activated, as were proteins involved in the cell cycle, cell adhesion and exocytosis. In conclusion, 3G CAR T cells had a higher degree of intracellular signaling activity than 2G CARs which may explain the increased proliferative capacity seen in 3G CAR T cells. The study also indicates that there may be other signaling pathways to consider when designing or evaluating new generations of CARs.
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| 19. |
- Kittikorn, Thorsak, et al.
(author)
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Enhancement of mechanical, thermal and antibacterial properties of sisal/polyhydroxybutyrate-co-valerate biodegradable composite
- 2018
-
In: JOURNAL OF METALS MATERIALS AND MINERALS. - : CHULALONGKORN UNIV, METALLURGY & MATERIALS SCIENCE RESEARCH INST. - 0857-6149. ; 28:1, s. 52-61
-
Journal article (peer-reviewed)abstract
- Lignocellulosic biocomposite is a promising biodegradable materials, though improvement of the interfacial adhesion between cellulose fibre and polymer matrix is still challenged. Therefore, this work investigated the effect of propionylation of sisal reinforced fibre in the sisal/polyhydroxybutyrate-co-valerate (PHBV) biocomposite. Propionylation involved esterification substitution of propionic anhydride to hydroxyl group of sisal fibre, where ester group (COOR) of propionylated fibre was successfully observed by Fourier transform Infrared spectroscopy (FTIR). Then mechanical and thermal properties were evaluated and biodegradation characteristics were assessed. The tensile strength and modulus of propionylated sisal/PHBV biocomposite were greater than unmodified sisal/PHBV, which revealed better compatibility at the interface. In addition, propionate moieties of sisal fibre could induce crystalline formation of PHBV, as determined by an increase of crystalline phase. The higher decomposition temperature (Td) and activation energy (Ea) of 155 kJ.mol(-1), determined by thermal gravimetric analyser (TGA), were strong confirmation of good thermal resistance of the propionylated sisal biocomposite. The storage modulus, as characterized by dynamic mechanical thermal analyser (DMTA), also revealed the improvement of stiffness. Bacterial growth tests evaluated the inhibition of bacterial growth on the PHBV biocomposites. It was clear that propionylation of sisal fibre decreased colonization of Staphylococcus aureus (SA) and Escherichia coli (E.coli).
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| 20. |
- Lundqvist, Ulrika, 1968, et al.
(author)
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Integrering av hållbar utveckling i utbildningen: Jämförelse Chalmers och KTH
- 2017
-
In: Proceedings of the 6:e Utvecklingskonferensen för Sveriges ingenjörsutbildningar.
-
Conference paper (peer-reviewed)abstract
- Det finns ett stort behov av att ingenjörer har kompetens inom hållbar utveckling. Chalmers och KTH har under flera år arbetat aktivt med integrering av hållbar utveckling i ingenjörsutbildningarna. Syftet med den här jämförelsen är att dra lärdomar från förändringsarbetet för integrering av hållbar utveckling i utbildningen vid KTH och Chalmers samt belysa relevanta delar av förändringsarbetet och några resultat från detta vid de två lärosätena, lyfta fram en del skillnader och likheter samt diskutera framgångsfaktorer och utmaningar. Några framgångsfaktorer är: tydliga mål som är förankrade i ledningen, centralt organiserat stöd för programansvariga och lärare, kontinuerlig uppföljning som synliggör framgångar och behov av vidareutveckling.
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