Scaffold-Based Temporomandibular Joint Cartilage Regeneration : Using Bone Marrow-Derived Mesenchymal Stem Cells

Reconstruction of lost or damaged cartilaginous structures of the temporomandibular joint (TMJ) presents a clinical challenge and current treatment options are limited. The potential for repair is poor, because cartilage is avascular and degenerated structures are traditionally surgically removed, to improve function and reduce the level of pain. The studies in this thesis were undertaken to explore the possibility for regeneration of TMJ cartilage by means of tissue engineering (TE). The main objective of this thesis was to develop a regenerative approach for degenerated TMJ cartilage, combining bone marrow-derived stem cells (BMSC) with a natural polymer scaffold. Study I is a pilot study, investigating the in vivo effect of the angiogenesis inhibitor, angiostatin, on BMSC seeded collagen scaffolds. After subcutaneous implantation in rats for two weeks, angiostatin downregulated the levels of inflammatory and angiogenic gene markers and decreased vessel formation in the constructs. However, histological examination disclosed that this strategy alone did not induce cartilage formation. Based on the above findings, and the observed lack of established methods for TMJ cartilage TE, a systematic literature review (Study II) was undertaken to assess the in vivo evidence for TMJ TE. In total, the search yielded 30 studies of ectopic and orthotopic models investigating regeneration of the TMJ disc, condyle, and synovial membrane, in five different species. Overall, the use of BMSC and natural polymer scaffolds was most frequently reported. With respect to regenerative potential, differentiated stem cells were reported to be superior to undifferentiated cells. The systematic review disclosed the beneficial effects of BMSC combined with scaffolds of natural polymers, such as collagen and gelatin. With respect to TMJ regeneration by TE, the preferred scaffolding material for investigation was gelatin, because of its biocompatibility, superior hydrogel-forming properties and lower costs in comparison with collagen. In Study III, a gelatin hydrogel was 3D printed, crosslinked with genipin and characterized in terms of swelling, stability, degradation, mechanical properties and cytotoxicity. The chondrogenic differentiation potential of human BMSC (hBMSC) seeded on the developed scaffolds was compared with that of hBMSC in traditional pellet or novel spheroid cultures. Genipin successfully prevented rapid degradation of the scaffolds, which supported cell attachment and proliferation without adverse cytotoxic effects. Scaffolds seeded with hBMSC followed the same trend in upregulation of chondrogenic gene markers, but at lower levels than for pellet and spheroid cultures. It was noteworthy that the hypertrophy marker collagen type 10 was downregulated in hBMSC on scaffolds, in comparison with spheroids and cell pellets. The chondrogenic differentiation of hBMSC on the 3D printed scaffolds was confirmed by Alcian blue and immunofluorescence staining. In Study IV, dehydrothermal (DHT) treatment was compared to ribose and the dual crosslinking with both DHT and ribose. The scaffolds were characterized with respect to swelling, stability, enzymatic degradation, and degree of crosslinking. Cell-seeding efficiency, attachment, proliferation, glycosaminoglycan (GAG) formation and differentiation of rat BMSC were compared between the groups. While the dual crosslinking resulted in the highest degree of crosslinking, stability, enzymatic resistance, mechanical properties, and proliferation, DHT had the highest cell seeding efficiency and viability. Ribose had the highest swelling capacity, but the lowest stability, enzymatic degradation, mechanical properties, cell seeding density and chondrogenic differentiation potential. However, no differences were observed with respect to GAG formation. In summary, inhibition of vascularization alone was not enough to stimulate chondrogenesis in TE constructs (Study I), indicating the need for alternative approaches. The current preclinical evidence clearly demonstrates the beneficial effects of using natural polymer scaffolds combined with MSC for TMJ TE (Study II). Gelatin, one such polymer, was found to be suitable for fabrication of 3D printed scaffolds, which support the proliferation and chondrogenic differentiation of hBMSC (Study III). Finally, dual crosslinking of 3D printed gelatin scaffolds with DHT and ribose enhanced the degree of crosslinking, mechanical properties, enzymatic resistance and stability (Study IV).Doktorgradsavhandlin

Validation of the AROME MetCoOp Model Wind Predictions using Radiosonde Observations. Investigating the Impact of wind prediction errors on the modelled transportation of radioactivity after the Chernobyl Accident

The main objective of this thesis was to investigate the error in the wind speed and wind direction predicted by the AROME MetCoOp model for the time period after the Chernobyl accident, using radiosonde data with and without adjusting for horizontal displacement. The second objective was to examine specific radiosonde soundings to investigate the error in wind direction along the movement of the plume over the first four days, using radiosonde observations with horizontal drift and discussing the significance of these errors for the transportation of the radioactivity. To do this, the radiosonde observations were adjusted for horizontal drift by using methods explained in Laroche and Sarrazin (2013), and it was applied to the analysis of the model wind predictions, so that it could be compared to the analysis without adjustment. Then the model data was interpolated for the data to have the same position in space and time as the radiosonde observations. Then the mean absolute error and mean error were found for each timestep and for different height bins. Before this there was a scatter plot analysis of the mean absolute error and removal of outliers. To investigate the error in selected radiosonde stations, polar plots were presented to visualize the difference in predicted and observed wind direction, giving a picture of the difference in the observed and predicted path of the plume. Among other findings, this thesis concluded that the horizontal displacement of radiosondes, when comparing radiosonde observations with the AROME model, was not necessary to include in the analysis seeing that there were very little difference between the analysis with adjustment for horizontal displacement of the radiosonde observations and the analysis without. It was further observed that there was a larger error below 1000 meters than above, and an under prediction of the rotation of the wind direction from the surface of the earth to the free atmosphere. Therefore this thesis also concluded that depending on the vertical position of the radioactivity there could be more or less deviations between the model predictions and the actual transportation. Further, this thesis also came to the conclusion, based on the errors in wind direction, that radioactivity above 1000 meters during the first few days could be transported more north than predicted, and the radioactivity below 1000 meters could be transported more towards the west than predicted

On Trapped Particle Dynamics in Rotating Frames

The rapid rotation of Jupiter and Saturn, combined with internal source of plasma provided by their moons Io and Enceladus respectively, creates a magnetodisk structure of the planetary magnetic field. The magnetodisk looks like a stretched dipole magnetic field in the equatorial region, where centrifugal force is largest. The centrifugal force, originating in the rotating frame, is known to have large contribution to the magnetodisk structure in the Jovian and Kronian magnetospheres. In order to investigate deviations in the dynamics of charged particles trapped in a magnetodisk compared to a pure dipole magnetic field, this thesis studies how centrifugal force influences a trapped particle's bounce motion as described by the so-called guiding centre approximation. Here a model characterising a trapped particle's bounce period in a rotating frame of reference is presented. It is evident that conservation of energy and conservation of first adiabatic invariant put constraints on the particle motion along the field line. The beta parameter is a boundary condition to the model that determines the rate of change between kinetic and potential energy along the field line, and describes to which degree the system is affected by rotation. The bounce period is larger than in a non-rotating frame when inverse parallel velocity component increases faster than mirror point latitude decreases, and shorter for the opposite case. How these components change in relation to each other varies as a function of beta. Small values of beta results in longer bounce periods for particles with small equatorial pitch angles, and shorter bounce periods for particles with large equatorial pitch angles. An effect of rotation when beta increases is that also particles with small pitch angles are confined towards equator, bouncing with shorter bounce periods compared to a non-rotating frame. The beta parameter, describing the ratio of centrifugal potential energy to kinetic energy at equator, is thus a prerequisite for the particle dynamics along the field line in a rotating frame

Examining the experiences of implementing a lifestyle intervention for overweight and obese children An interview study on the barriers and enhancers when implementing an intervention program in Norwegian municipalities

Masteroppgave folkehelsevitenskap- Universitetet i Agder, 2015Background: Childhood obesity is one of the 21st century’s most serious public health challenges. In Norway, health nurses are obligated to record children’s body mass and children who are classified as overweight or obese should be offered a follow up through lifestyle programs. There has been a lack of such lifestyle programs, however, some municipalities have implemented intervention programs to support overweight and obese children and their families’ lifestyle changes. Aim: To examine how a lifestyle intervention focusing on promoting healthy lifestyle habits in overweight and obese children and their families in three different Norwegian municipalities was implemented and conducted. The intervention focused on physical activity, diet and individual guidance. Important enhancers and barriers related to the implementation process were identified. Methods: In depth interviews were conducted with representatives (n=5) involved in the implementation process in three different municipalities. All interviews were recorded digitally, transcribed verbatim and analysed using systematic text condensation. Results: An initiator to establish agreements in the municipality council was identified as an important enhancer in the implementation. Barriers in the implementation were related to the cooperation between the program facilitators, municipal council and the health nurses. Resistance from the participating children’s parents and a lack of program founding were also identified as barriers. There was a lack of structured evaluations of the intervention programs. The intervention programs components were identified as important focus areas, including connection to local community, physical activity sessions, diet courses, individual counselling and involvement of the entire family. Conclusion: Involvement of a determined individual with strong sense of commitment seems essential for implementing such intervention programs. For future work, better strategies to involve health nurses and how they should approach the families are needed. Thorough program evaluation should be conducted to examine the intervention program’s effect, why they were successful or not, and to ensure future funding

Regional and global changes in TCR [alpha][beta] T cell repertoires in the gut are dependent upon the complexity of the enteric microflora

The repertoire of gut associated T cells is shaped by exposure to microbes, including the natural enteric microflora. Previous studies compared the repertoire of gut associated T cell populations in germ free (GF) and conventional mammals often focussing on intra-epithelial lymphocyte compartments. Using GF, conventional and monocolonised (gnotobiotic) chickens and chicken TCRbeta-repertoire analysis techniques, we determined the influence of microbial status on global and regional enteric TCRbeta repertoires. The gut of conventionally reared chickens exhibited non-Gaussian distributions of CDR3-lengths with some shared over-represented peaks in neighbouring gut segments. Sequence analysis revealed local clonal over-representation. Germ-free chickens exhibited a polyclonal, non-selected population of T cells in the spleen and in the gut. In contrast, gnotobiotic chickens exhibited a biased repertoire with shared clones evident throughout the gut. These data indicate the dramatic influence of enteric microflora complexity on the profile of TCRbeta repertoire in the gut at local and global levels

Rekruttering 2.0 : en studie av screening ved hjelp av sosiale medier

Hvilken effekt har screening via sosiale medier på bedrifters valg av ansatt? Denne studien viser resultatene fra utførte dybdeintervjuer og eksperiment basert på bruken og effekten av sosiale medier i utvelgelsesprosessen. Det ble gjennomført totalt 13 intervjuer med åtte ulike bedrifter, og eksperimentet ble utført på 120 deltakere som fikk tildelt en rolle som HR-ansvarlig. Funnene ble deretter analysert for å se hvordan bedrifter i Norge bruker sosiale medier i utvelgelsesprosessen og hvilken effekt de sosiale mediene har på match mellom arbeidsbeskrivelse og personen som ansettes. Resultatene fra disse to forskningsmetodene gir bevis for at screening via sosiale medier, spesielt Facebook, har en effekt på valg av ansatt. Formålet med studien har vært å teste eksisterende forskning knyttet til temaene rekruttering ,screening og sosiale medier i en ny kontekst. Studien kan bidra til økt forståelse av hvordan man kan bruke sosiale medier i utvelgelsesprosessen og dermed forbedre kvaliteten av dette screening verktøyet. Videre kan det medføre bedre kvalitet på rekrutteringsprosessen innad i bedriftene og ha en positiveffekt på rekrutteringen i norsk næringsliv og offentlig sektor. Ved gjennomgang av eksisterende teori, ble det identifisert et forskningsgap knyttet til effekten av sosiale medier i norsk kontekst. Ved å fylle dette forskningsgapet, håper forskerne dermed at bedrifter kan dra nytte av denne studien og få en bredere forståelse av effekten sosiale medier har på utvelgelses prosessen

Etablering av beredskap for cyberhendelser

Etablering av beredskap for cyberhendelser. Denne masteroppgaven analyserer cybersikkerhetsstrategier og -praksis hos Glencore Nikkelverk, med fokus på forberedelse og håndtering av cyberhendelser. Med økende digitalisering og endrede trusselbilder, avdekker oppgaven at det er behov for forbedring knyttet til beredskapen mot digitale trusler. Kvalitative metoder ble benyttet for datainnsamling, gjennom intervjuer av ledere og sikkerhetsansvarlige er det funnet at Nikkelverket har en moderat grad av beredskap for cyberhendelser. Selskapet har tatt i bruk teorier og rammeverk for cybersikkerhet, men risikoforståelsen relatert til det digitale domenet krever forbedring. Økende digitalisering av samfunnet, inkludert viktige samfunnsfunksjoner og industriell produksjon, har endret trusselbildet. Det kreves beredskap mot digitale trusler på linje med fysisk beredskap i dagens samfunn. Dette er et relativt nytt fagområde, og mange bedrifter mangler erfaring med etablering av beredskap for cyberhendelser. Denne masteroppgaven har adressert følgende tiltak for å styrke beredskapen for cyberhendelser ved Glencore Nikkelverk: - Etablering av bedre dialog mellom forskjellige funksjoner i bedriften, eksempelvis IT-avdelingen, beredskapsstaber, industrivernledelsen og ledergruppen. - Risikoanalyser bør gjennomføres og oppdateres regelmessig. - Det bør utarbeides en beredskapsanalyse basert på resultatene fra risikoanalysene. - Beredskapsplaner, tiltakskort for cyberhendelser og en plan for kompetanseutvikling, trening og øving bør etableres ut fra resultatene i beredskapsanalysen. - Samarbeidsavtalen med det eksterne IT-sikkerhetsselskapet bør revideres for klarhet om ansvarsfordeling ved en cyberhendelse. Opprettholdelse av konkurranseposisjonen i et trusselutsatt, digitalisert landskap vil kreve kontinuerlig forbedring, bevissthet og kompetanseheving blant ansatte. Implementeringen av teorier og rammeverk for håndtering av cyberhendelser er en pågående prosess hos Glencore Nikkelverk. Ved å adressere de identifiserte svakhetene, kan bedriften styrke sin beredskap og evne til å håndtere cyberhendelser

Functional Somatic Symptoms in Children and Adolescents

This open access book sets out the stress-system model for functional somatic symptoms in children and adolescents. The book begins by exploring the initial encounter between the paediatrician, child, and family, moves through the assessment process, including the formulation and the treatment contract, and then describes the various forms of treatment that are designed to settle the child’s dysregulated stress system. This approach both provides a new understanding of how such symptoms emerge – typically, through a history of recurrent or chronic stress, either physical or psychological – and points the way to effective assessment, management, and treatment that put the child (and family) back on the road to health and well-being