| 11. |
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| 12. |
- Forslund, Carina
(författare)
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BMP treatment for improving tendon repair. Studies on rat and rabbit Achilles tendons
- 2002
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- We wanted to improve tendon healing by adding a growth factor. Bone Morphogenetic Proteins (BMPs) are well known to stimulate bone healing and bone formation. The local environment is of major importance for cell differentiation after a BMP has been added. Cartilage Derived Morphogenetic Proteins (CDMPs) -1, -2 and -3 (BMP 14, 13 and 12 or GDF 5, 6 and 7) form a subgroup in the BMP-family and are closely related to OP-1 (BMP 7). CDMP implants have been shown to induce bone and cartilage as well as tendon and ligament-like tissue. Our hypothesis has therefore been that if a BMP were added in a tendon environment, a tendon-like tissue would be induced. We have developed models in rats and rabbits where the Achilles tendon is transsected. To influence tendon healing, different BMPs (OP-1, CDMP-1. -2 and -3) were added, either on a collagen carrier, or as a local injection into the tendon defect. The tendons were evaluated by histology and mechanical testing at different time-points after transection. The results show that also when the mechanical environment would favour the formation of a tendon-like tissue, OP-1 reduced tendon strength in aid of bone formation. In contrast, CDMP-1, -2 and -3 had a beneficial effect upon tendon healing in rats. More callus tissue was produced than in controls, and strength and stiffness were improved, although minor amounts of bone and cartilage were detected in the tendon callus. Cartilage and bone formation sometimes occur normally during Achilles tendon healing in rats. In the rabbit model, where the healing situation is more similar to the clinical situation, the positive result with CDMP-2 was repeated. Moreover, in rabbits no bone or cartilage was found. The results suggest that conservative treatment of Achilles tendon ruptures with injection of a CDMP in combination with early rehabilitation might afford a good alternative to surgical treatment.
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| 13. |
- Erixon, Per-Olof, 1954-
(författare)
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Pedagogiskt arbete i romanens prisma : Upplevelser av den svenska folkskolan under ett omvälvande sekel
- 2002
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Bok (övrigt vetenskapligt/konstnärligt)abstract
- I studien Pedagogiskt arbete i romanens prisma inringas ett motiv i den svenska prosalitteraturen, skolmotivet, med speciell tonvikt på de värderingar av skolan, lärarna, eleverna, bildning etc. som litteraturen förmedlar. Föresatsen är inte primärt att ur det skönlitterära materialet frambringa ny kunskap om den svenska skolans innehållsliga och organisatoriska förändringar. Vad skönlitteratur på ett mer subtilt sätt framför allt kan bidra med är en belysning av hur de förändringar som sker uppfattas och bearbetas av dem som är verksamma i skolan, dvs. lärarna själva. På denna nivå kan skolromaner, dvs. romaner skrivna av utbildade och verksamma lärare, bidra med ny kunskap.
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| 14. |
- Dahlin, Bo
(författare)
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Den tunga vetenskapen : Lärarstuderandes uppfattningar av naturvetenskap med kontroversen mellan Goethes och Newtons optik som utgångspunkt
- 2002
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Rapport (refereegranskat)abstract
- Science literacy, dvs förståelse för naturvetenskapens karaktär och innehåll, har i många länder under flera decennier varit ett övergripande mål för skolans undervisning i naturkunskap/ naturvetenskap. Huvudsyftet med denna rapport äratt undersöka, beskriva och diskutera blivande NA-lärares uppfattningar av vad som kännetecknar naturvetenskaplig kunskap. Rapporten syftar också till att belysa relationen mellan science literacy och bildning. Den utgår från ett hermeneutiskt- fenomenologiskt grundperspektiv, vilket tillämpas både på naturvetenskapen som sådan och på empiriska data. Det hermeneutiskt-fenomenologiska perspektivet på naturvetenskap exemplifieras med Johann W Goethes färglära
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| 15. |
- Bläckberg, Jonas
(författare)
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Hepatitis B virus infection and genomic changes from a long-term perspective
- 2002
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Hepatitis B virus is a non-cytopathic virus with a small, circular, partially double-stranded DNA of 3.2 kb. It causes acute and chronic inflammatory liver disease and hepatocellular carcinoma (HCC). Retesting of stored sera from an outbreak of acute hepatitis in 1969-72 allowed identification of 126 cases of acute hepatitis B. No chronic carriers expressing hepatitis B surface antigen (HBsAg) could be found among 100 patients at follow-up 25-30 years later. Sixteen patients with documented self-limited acute hepatitis were evaluated further. HBV DNA could not be detected by PCR in serum or PBMCs. However, HBV DNA could be detected in the liver specimens of two patients 30 years after having an acute hepatitis B infection. Both patients had histological signs of minor liver inflammation. When selected genomic sequences of the strains detected in the liver were compared with the primary infecting strains in serum collected 30 years earlier, they were identical. Mutations in the precore and core promoter (cp) regions of the HBV genome have been associated with a lack of detectable hepatitis B e antigen (HBeAg). The precore and cp regions of viral strains from 83 chronic HBV carriers, including 16 carriers sampled during HBeAg seroconversion, were sequenced. The development of precore and cp mutations appeared to be a separate event from the HBeAg seroconversion. Mutations in strains from 16 patients with HBV infection and HCC were analyzed. Sequencing of the preS, S, X, and precore regions showed a high prevalence (50%) of mutations affecting part of the preS2 region which codes for B and T cells epitopes.
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| 16. |
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| 17. |
- Assefa, Getachew, et al.
(författare)
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Life Cycle Assessment of Thermal Treatment Technologies : An environmental and financial systems analysis of gasification, incineration and landfilling of waste
- 2002
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- A technology which is currently developed by researchers at KTH is catalytic combustion which is one component of a gasification system. Instead of performing the combustion in the gas turbine by a flame, a catalyst is used. When the development of a new technology (as catalytic combustion) reaches a certain step where it is possible to quantify material-, energy- and capital flows, the prerequisites for performing a systems analysis is at hand. The systems analysis can be used to expand the know-how about the potential advantages of the catalytic combustion technology by highlighting its function as a component of a larger system. In this way it may be possible to point out weak points which have to be investigated more, but also strong points to emphasise the importance of further development.The aim of this project was to assess the energy turnover as well as the potential environmental impacts and economic costs of thermal treatment technologies in general and catalytic combustion in particular. By using a holistic assessment of the advantages and disadvantages of catalytic combustion of waste it was possible to identify the strengths and weaknesses of the technology under different conditions. Following different treatment scenarios have been studied: (1) Gasification with catalytic combustion, (2) Gasification with flame combustion, (3) Incineration with energy recovery and (4) Landfilling with gas collection. In the study compensatory district heating is produced by combustion of biofuel. The power used for running the processes in the scenarios is supplied by the waste-to-energy technologies themselves while compensatory power is assumed to be produced from natural gas. The emissions from the system studied were classified and characterised using methodology from Life Cycle Assessment into the following environmental impact categories: Global Warming Potential (also called the green house effect), Acidification Potential, Eutrophication Potential and finally Formation of Photochemical Oxidants.It is obvious that a decreased use of landfilling in favour of an increased energy recovery from waste is positive from all considered impact categories. Gasification with energy recovery in a combi cycle using catalytic combustion in the gas turbine is the most competitive technology from primarily an environmental point of view. The financial costs are however a bit higher than for incineration with energy recovery. This conclusion depends, however, on the assumption that the gasification and catalyst technologies work as the researchers presume and that the fuel is of high quality. For this, the pelletising unit is vital in the technology chain.A comparison of the catalytic combustion and the flame combustion shows that all impact categories except acidification, eutrophication and photochemical oxidants remain the same. The gasification process is identical between the two alternatives; it is just the combustion technology in the gas turbine that is different. This explains why the fuel consumption and the financial costs are not changed (a minor extra investment is made for the catalyst but is not noticeable in comparison to the total impact). Emissions of greenhouse gases are also identical. For the other impact categories there are differences for several of the emissions involved in the impact assessment but NOX is clearly the dominating one.Gasification with catalytic combustion is competitive to incineration. The small difference for eutrophication is within the error margin and is strongly dependent on the reduction of NOX in the incineration plant. The explanation to this result is that a combi cycle in combination with natural gas as the alternative power generation is a better system solution than incineration with biofuel as compensatory fuel. Financial costs are somewhat higher than for incineration but could also claimed to be within the error margin since the inventory of costs are more uncertain due to the fact that there is no plant with gasification and catalytic combustion in operation.
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| 18. |
- Antonsson, Ann-Beth, et al.
(författare)
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Isocyanater och bilglasarbete. Vilka är problemen och hur skyddar man sig?
- 2002
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Bilglasarbete innebär arbete med lim som innehåller isocyanater. Exponering för isocyanater kan ske genom hudkontakt och inandning av isocyanater vid limning, genom inandning av isocyanater vid demontering av rutan, om ett verktyg som alstrar mycket värme används samt om limspill tas bort genom att upphettas. Mätningar har gjorts för att studera bildning av isocyanater då olika verktyg används för demontering av rutor. Vid demontering med två verktyg, Excalibur (ungefär samma som Equalizer) samt sågning med tvinnad guldtråd bildades isocyanater i låga halter. Därför rekommenderas att dessa verktyg ej används. Tidigare mätningar tyder på att limning av bilrutor inte utgör något problem när det gäller inandning av isocyanater. Däremot förekommer hudkontakt med limmet vid limning. All hudkontakt med PUR-lim ska undvikas, eftersom hudkontakt misstänks kunna ge astma. Blodprover har tagit på tolv bilglasarbetare för analys av omvandlingsprodukter av isocyanater. Halten i blodproverna låg under analysmetodens detektionsgräns. Intervjuer har gjorts med tio personer som anmält arbetsskada som kan bero på bilglasarbete. Åtgärder för att minska risken med isocyanater vid bilglasarbete beskrivs.
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| 19. |
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