Made available in DSpace on 2014-12-17T14:07:12Z (GMT). No. of bitstreams: 1 UlissesTB.pdf: 2103703 bytes, checksum: 784868c57be7336a1a7601f71664ac81 (MD5) Previous issue date: 2006-10-31 / The oil production in mature areas can be improved by advanced recovery techniques. In special, steam injection reduces the viscosity of heavy oils, thus improving its flow to surrounding wells. On the other hand, the usually high temperatures and pressures involved in the process may lead to cement cracking, negatively affecting both the mechanical stability and zonal isolation provided by the cement sheath of the well. The addition of plastic materials to the cement is an alternative to prevent this scenario. Composite slurries consisting of Portland cement and a natural biopolymer were studied. Samples containing different contents of biopolymer dispersed in a Portland cement matrix were prepared and evaluated by mechanical and rheological tests in order to assess their behavior according to API (American Petroleum Institute) guidelines. FEM was also applied to map the stress distribution encountered by the cement at bottom bole. The slurries were prepared according to a factorial experiment plan by varying three parameters, i.e., cement age, contents of biopolymer and water-to-cement ratio. The results revealed that the addition of the biopolymer reduced the volume of free water and the setting time of the slurry. In addition, tensile strength, compressive strength and toughness improved by 30% comparing hardened composites to plain Portland slurries. FEM results suggested that the stresses developed at bottomhole may be 10 to 100 times higher than the strength of the cement as evaluated in the lab by unconfined mechanical testing. An alternative approach is proposed to adapt the testing methodology used to evaluate the mechanical behavior of oilwell cement slurries by simulating the confined conditions encountered at bottornhole / A cimenta??o de po?os ? pr?tica comum na ind?stria do petr?leo. Po?os antigos que apresentam baixo rendimento passam a produzir mais quando se adota o processo de recupera??o secund?ria. Um dos procedimentos que pode ser adotado nestes po?os ? a introdu??o de vapor d'?gua sob press?o para que o petr?leo tenha sua viscosidade reduzida e flua com mais facilidade para os po?os da circunvizinhan?a. A temperatura elevada provoca fissura??o nas bainhas dos po?os e conseq?ente perda de estanqueidade devido ao car?ter r?gido das bainhas de cimento Portland. Comp?sitos de cimento Portland aditivados com biopol?mero foram analisados com rela??o a tr?s aspectos: propriedades mec?nicas previstas nas normas da ABNT e espec?ficas para a ind?stria do petr?leo; propriedades reol?gicas tamb?m previstas em norma e avalia??o num?rica por elementos finitos simulando bainhas de po?os de petr?leo. As pastas foram preparadas seguindo planejamento fatorial pr?vio, com varia??o de tr?s fatores: idade do cimento Portland, concentra??o de biopol?mero e fator ?gua/cimento. Os resultados mostraram que a presen?a do biopol?mero elimina forma??o de ?gua livre; funciona como acelerador de pega, reduzindo o tempo de espessamento; aumenta as resist?ncias ? compress?o e ? tra??o em at? 30 % e a tenacidade-resili?ncia em at? 30 %. A an?lise por elementos finitos mostrou que a ordem de grandeza das tens?es despertadas pela temperatura no fundo do po?o chega a ser 10 e 100 vezes superior ?s resist?ncias ? compress?o e ? tra??o, respectivamente, das pastas ensaiadas em laborat?rio. Isto levou ? constata??o de que os ensaios n?o confinados de propriedades mec?nicas n?o conseguem medir o comportamento real das pastas, sendo necess?ria a adapta??o dos mesmos para a condi??o confinada. Um ensaio alternativo ? proposto por meio de um equipamento (SCERB) que simula as condi??es de fundo de po?o

Arc welding still requires deeper process understanding and more accurateprediction of the heat transferred to the base metal. This can be provided by CFD modelling.Most works done to model arc discharge using CFD consider the arc corealone. Arc core simulation requires applying extrapolated experimental data asboundary conditions on the electrodes. This limits the applicability. To become independent of experimental input the electrodes need to be included in the arcmodel. The most critical part is then the interface layer between the electrodesand the arc core. This interface is complex and non-uniform, with specific physicalphenomena.The present work reviews the concepts of plasma and arc discharges that areuseful for this problem. The main sub-regions of the model are described, andtheir dominant physical roles are discussed.The coupled arc-electrode model is developed in different steps. First couplingsolid and fluid regions for a simpler problem without complex couplinginterface. This is applied to a laser welding problem using the CFD softwareOpenFOAM. The second step is the modelling of the interface layer betweencathode and arc, or cathode layer. Different modelling approaches available inthe literature are studied to determine their advantages and drawbacks. One ofthem developed by Cayla is used and further improved so as to satisfy the basicprinciples of charge and energy conservation in the different regions of thecathode layer. A numerical procedure is presented. The model, implementedin MATLAB, is tested for different arc core and cathode conditions. The maincharacteristics calculated with the interface layer model are in good agreementwith the reference literature. The future step will be the implementation of theinterface layer model in OpenFOAM.

Introdução: Os processos degenerativos vêm sendo considerados determinantes da progressão do déficit neurológico na esclerose múltipla (EM) e são associados sobretudo à perda neuronal e axonal. A patologia na substância branca (SB) manifesta-se pela quebra de membranas e perda da complexidade microestrutural dos tratos cerebrais, o que pode ser estudado indiretamente pelas alterações nos índices de fração de anisotropia (FA) e difusividade média (DM), obtidos por meio das análises das imagens por tensores de difusão (diffusion tensor imaging - DTI). Essa técnica oferece outros dois índices mais específicos, a difusividade axial () e difusividade radial (), que são associados aos processos de perda axonal e desmielinização, respectivamente. A perda neuronal na substância cinzenta (SC) pode ser avaliada pelo grau de atrofia do córtex cerebral. Este estudo tem como objetivos mensurar os índices de DTI na maior comissura cerebral, o corpo caloso (CC), e o grau e distribuição da atrofia cortical em indivíduos com EM remitente-recorrente (EMRR) e baixos escores de incapacidade funcional, correlacionando essas alterações com o volume de lesões macroscópicas e os principais parâmetros clínicos. Método: 31 indivíduos (22 mulheres, idade média 30,5 anos ± 8,7) com EMRR e um grupo controle (GC) composto por 34 indivíduos saudáveis (27 mulheres, idade média 32,3 anos ± 7,8) realizaram exames de crânio em aparelho de ressonância magnética de 3 Tesla (3T), sendo adquiridas imagens de DTI com 32 direções de gradiente, obtendo-se os índices de FA, DM, e de cinco segmentos na secção sagital do corpo caloso (CC). Através da segmentação de imagens volumétricas ponderadas em T1 foram obtidas as espessuras corticais regionais nos grupos. Esses resultados foram correlacionados com os volumes lesionais de imagens ponderadas em T1 e T2/FLAIR e os escores da escala expandida do estado de incapacidade (Expanded Disability Status Scale - EDSS), considerando-se significativos resultados com p< 0,05. Resultados: Os índices de FA, DM e do CC estavam difusamente alterados no grupo EMRR e a , alterada significativamente no esplênio, tronco médio anterior e tronco médio posterior do CC. Observou-se atrofia cortical significativa no terço anterior dos lobos temporais, bilateralmente, e nas regiões parietal inferior, insular e fronto-orbitária direitas, com uma tendência à atrofia no giro frontal superior esquerdo. As FA, DM e correlacionaram-se com os volumes lesionais T1 e, mais significativamente, com os volumes lesionais T2/FLAIR, porém não houve correlação entre os volumes lesionais e a . A espessura cortical no grupo EMRR apresentou correlações com ambos os volumes lesionais, mais significativamente com as lesões em T1. O escore médio da EDSS era 1,1 ± 0,9 (variando de 0-3), apresentando correlações com a DM e a no esplênio, tronco médio anterior e posterior do CC, com uma correlação com a no tronco médio posterior. O EDSS correlacionou-se com a espessura cortical na topografia do giro frontal superior esquerdo. Discussão e conclusão: Houve alteração difusa nos índices de FA, DM e nos segmentos do CC, com acometimento mais localizado, predominantemente médio posterior, da , o que pode sugerir desmielinização difusa do CC, porém axonopatia ou degeneração mais acentuada em algumas regiões da SB. A atrofia cortical também apresentou uma distribuição regional característica, afetando sobretudo as regiões temporais, bilateralmente, parietal inferior, insular e fronto-orbitária direitas. As correlações encontradas entre os índices de DTI e a espessura cortical e os volumes lesionais demonstraram que, ao menos em parte, as degenerações das SB e SC podem ser relacionadas à degeneração Walleriana, secundária ao acúmulo de placas lesionais. As correlações entre a DM, de alguns segmentos do CC e a espessura cortical do giro frontal superior com os escores da EDSS favoreceram à hipótese de que a degeneração tecidual na EM foi um fator preponderante na progressão do déficit neurológico na EMRR / Introduction: The degenerative processes are gaining attention as predictors of the neurological deficit in multiple sclerosis (MS), being reflected by the degree of axon loss and central nervous system atrophy. The white matter pathology (WM) is characterized by cellular membranes disruption and loss of the microstructural complexity, which can be accessed by the diffusion tensor imaging (DTI) indices of fractional anisotropy (FA) and mean diffusivity (MD). This imaging technique also offers two more specific indices: the axial diffusivity () and radial diffusivity (), which are useful to differentiate between axon loss and demyelination, respectively. The gray matter (GM) neuronal loss can be accessed by the degree of cortical atrophy. The aim of this study is to measure the DTI indices in the greatest WM commisure, the corpus callosum (CC), and the degree and distribution of cortical atrophy in patients with relapsing remitting MS (RRMS) and low disability scores, correlating them to the macroscopic lesion load and the main clinical scores. Method: 31 RRMS patients (22 women, mean age 30.5 years ± 8.7) and 34 healthy control (HC) subjects (27 women, mean age 32.3 years ± 7.8) were submitted to brain examinations in a 3T magnetic resonance image scanner. From DTI with 32 gradient encoding directions were extracted the indices of FA, MD, and , which were measured in 5 segments of the mid-sagital section of the corpus callosum (CC). The cortical thickness was obtained from the segmentation of volumetric T1 images. These results were correlated with the macroscopic lesion loads in the T1 and T2/FLAIR images and the scores in the Expanded Disability Status Scale EDSS, considering significant the results with p< 0.05. Results: The FA, MD and were diffusively abnormal in all 5 segments of the CC in the RRMS group and the was abnormal only in the splenium, anterior midbody and posterior mid-body. The anterior area of the both temporal lobes and right inferior parietal, some orbital-frontal and insular regions showed significant atrophy, with a tendency of atrophy in the superior frontal gyrus. The FA, MD and correlated with the T1 lesion load and, more significantly, with the T2/FLAIR lesion load. The cortical thickness correlated with T1 and T2/FLAIR lesion loads, more significantly with the T1 lesion load. The mean EDSS in the RRMS group was 1.1 ± 0.9 (range 0-3), correlating with the MD and of the splenium, anterior and posterior mid-body of the CC. The EDSS correlated to cortical thickness in the topography of the superior frontal gyrus. Discussion and conclusion: The FA, MD and are diffusively abnormal in the CC, with abnormalities in the , restricted to the medial and posterior segments. These results can be interpreted as signs of diffuse demyelination in the CC and a predominance of axonopathy or more advanced degeneration in some segments. The cortical atrophy also followed a characteristic regional distribution, affecting predominantly the bilateral temporal lobes, and inferior parietal, orbital-frontal and insular regions, in the right hemisphere. The correlations found between the DTI indices and the cortical thickness and the macroscopic lesion loads show that, at least partially, the WM and GM degeneration can be related to Wallerian degeneration secondary to macroscopic lesion accumulation. The correlations between the DM, , in some of the CC segments, and cortical thickness, in the superior frontal gyrus, and the EDSS scores reinforces the hypothesis that the degenerative processes in MS can play a role in the disability status of the patients

Orientador: Tatiane Maria Rodrigues / Resumo: Em folhas de diversas espécies vegetais, a bainha de células que envolve os feixes vasculares se estende em direção à epiderme em ambas as faces do limbo formando extensões da bainha do feixe (EBF), o que caracteriza folhas heterobáricas. Folhas que não apresentam EBF são chamadas homobáricas. Pesquisas demostram que folhas homobáricas garantem maior difusão lateral de gases, enquanto as EBF podem atuar na condução de água e aumentar o desempenho fotossintético foliar garantindo a transferência de luz para as camadas mais internas do mesofilo. As diferenças morfofuncionais entre os dois tipos foliares parecem estar relacionadas ao ambiente onde as plantas ocorrem e à sua distribuição nos diferentes estratos vegetacionais. Entretanto, para formações vegetais no Brasil não foram encontrados estudos sobre a distribuição de espécies com folhas homobáricas e heterobáricas. Esse trabalho teve como objetivo estudar a anatomia foliar de espécies herbáceas, arbustivas e arbóreas na floresta estacional semidecídua, cerradão e cerrado stricto sensu a fim de identificar folhas homobáricas e heterobáricas, buscando associar a presença/ausência de EBF com o porte das plantas e com o ambiente. Quadrantes de 20mX20m foram demarcados nas fragmentos vegetacionais. Folhas completamente expandidas foram coletadas de 59 espécies no cerradão (32 arbóreas; 19 arbustos e 8 herbáceas); 68 espécies no cerrado stricto sensu (21 arbóreas; 30 arbustos e 17 herbáceas) e 51 espécies na floresta estacional ... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: In leaves of several plants species, the vascular bundle sheath extends toward the epidermis on both sides of the blade forming bundle sheath extensions (BSE), characterizing heterobarics leaves. Leaves lacking BSE are called homobarics. Research shows that homobaric leaves provide greater lateral movements of gases, while the BSE can act conducting water and increasing the leaf photosynthetic performance, what ensures the transference of light to the inner layers of the mesophyll. The morphological and functional differences between the two leaf types seem to be related to the environment where the plants occur and their distribution in the different vegetation strata. However, there are no studies on the distribution of species with homobarics and heterobarics leaves for vegetation formations in Brazil. This work aimed to study the leaf anatomy of herbs, shrubs and trees in semideciduous seasonal forest, cerradão and cerrado stricto sensu to identify homobarics and heterobarics leaves, searching to associate the presence / absence of BSE to the plant strata and environmental characteristics. Quadrants of 20mX20m were marked in vegetation fragments. Fully expanded leaves were collected from 59 species in the cerradão (32 tree, 19 shrubs and 8 herbs); 68 species in the cerrado stricto sensu (21 tree, 30 shrubs and 17 herbs) and 51 species in the semideciduous seasonal forest (23 tree, 17 shrubs and 11 herbs). Samples of the leaf blade were processed according to standard tech... (Complete abstract click electronic access below) / Mestre

Abstract The myelin sheath is a crucial component of vertebrate nervous systems. Myelin is formed as the plasma membrane of a glial cell is wrapped around a neuronal axon. The presence of myelin enables the fast transmission of neuronal impulses, and degradation or dysfunction of myelin results in severe neurological symptoms. Molecular composition of myelin is unique, and many myelin proteins are not present elsewhere in the body. A myelin enzyme, 2′,3′-cyclic nucleotide 3′-phosphodiesterase (CNPase), is found in specific regions within the myelin sheath and is one of the most abundant proteins in the brain. Substrates for CNPase catalytic activity are formed during brain damage. CNPase also interacts with the cytoskeleton and cell membranes, and it is thought to play a role during myelin formation. Mice that lack CNPase suffer from axonal degeneration and die early. The aim of this study was to characterise CNPase structure and function. To this end, a system was first developed to produce the protein for subsequent analyses. The aim was to characterise the catalytic mechanism of CNPase by determining its three-dimensional molecular structure at different stages of the catalytic reaction. The interactions between CNPase and other molecules related to its function would also be characterised. Finally, the structure of the full-length protein would be used to understand of the function of the uncharacterised N-terminal domain. Using X-ray crystallography, the structure of the CNPase catalytic domain was determined in the presence of substrate and product molecules. These data, complemented with analyses of mutationally inactivated enzyme variants, were used to examine the catalytic reaction at the molecular level. The catalytic domain structure was compared to homologous enzymes from diverse organisms. The interaction between CNPase and the calcium-sensing protein calmodulin was characterised. The solution structure of full-length CNPase was determined using small-angle X-ray scattering, and protein sequence databases were utilised to determine CNPase conservation during animal evolution. The results provide novel information on the catalytic activity and overall function of CNPase. Further studies will be necessary to determine its specific role, but it is increasingly clear that CNPase can perform multiple important tasks within the nervous system. / Tiivistelmä Myeliinituppi on tärkeä osa selkärankaisten hermostoa. Myeliiniä muodostuu, kun gliasolun solukalvo kiertyy hermosolun aksonin ympärille. Myeliini mahdollistaa hermoimpulssien nopean välityksen, ja sen tuhoutuminen ja vajaatoiminta aiheuttavat vakavia neurologisia oireita. Myeliinin molekyylikoostumus on ainutlaatuinen, ja monet myeliiniproteiineista eivät esiinny muualla elimistössä. Myeliinissä esiintyvää entsyymiä, 2′,3′-syklisten nukleotidien 3′-fosfodiesteraasia (CNPaasi), esiintyy runsaasti tietyillä myeliinialueilla, ja se on yksi aivojen runsaslukuisimmista proteiineista. Substraatteja CNPaasin katalyyttiselle aktiivisuudelle muodostuu aivovaurion aikana. CNPaasi on myös vuorovaikutuksessa solun tukirangan ja solukalvon kanssa, ja sen uskotaan vaikuttavan myeliinin muodostumiseen. Hiiret, joilta puuttuu CNPaasi, kärsivät aksonien rappeumista ja kuolevat ennenaikaisesti. Tämän tutkimuksen tavoite oli karakterisoida CNPaasin rakennetta ja toimintaa. Tätä tarkoitusta varten ensin kehitettiin menetelmä analysoitavan proteiinin tuottamiseksi. Tavoitteena oli karakterisoida CNPaasin katalyyttinen mekanismi määrittämällä sen kolmiulotteinen molekyylirakenne katalyysireaktion eri vaiheissa. Myös CNPaasin vuorovaikutuksia sen toimintaan liittyvien molekyylien kanssa tutkittiin. Lopuksi kokopitkän proteiinin rakenteen avulla selvitettiin karakterisoimattoman aminoterminaalisen alayksikön toimintaa. CNPaasin katalyyttisen alayksikön rakenne määritettiin käyttäen röntgenkristallografiaa substraatti- ja tuotemolekyylien läsnäollessa. Rakennetta, täydennettynä mutaatioilla inaktivoitujen entsyymimuunnosten analyysillä, käytettiin katalyyttisen reaktion molekyylitason karakterisointiin. Katalyyttisen alayksikön rakennetta verrattiin eri organismeissa esiintyviin homologisiin entsyymeihin. CNPaasin ja kalsiumia sitovan kalmoduliinin vuorovaikutusta karakterisoitiin. Kokopitkän CNPaasin liuosrakenne selvitettiin pienkulmaröntgensironnan avulla, ja CNPaasin sekvenssin säilymistä eläinten evoluution aikana tarkasteltiin proteiinisekvenssitietokantoja käyttämällä. Tulokset antavat uutta tietoa CNPaasin katalyyttisestä aktiivisuudesta ja tämän arvoituksellisen entsyymin toiminnasta. Jatkotutkimukset ovat tarpeen sen täsmällisen roolin selvittämiseksi, mutta on kasvavassa määrin selvää, että CNPaasi pystyy suorittamaan useita tärkeitä tehtäviä hermostossa.

Um eine verbesserte Therapieoption mit weniger Schmerzen und Nebenwirkun-gen für Patienten mit Depigmentierungsstörungen wie Vitiligo zu entwickeln, wurde eine Methode zur nichtinvasiven Gewinnung von autologen Melanozyten aus der Haarwurzel genutzt. Die Haarwurzel als einfach zugängliches Stammzell-reservoir bietet die Möglichkeit, Vorläufermelanozyten aus der äußeren Haar-wurzelscheide zu isolieren, differenzieren und zu proliferieren. Für zukünftige autologe Transplantationsversuche wurden in dieser Arbeit die kultivierten hu-manen Melanozyten aus der äußeren Haarwurzelscheide (Human Melanocytes from the Outer Root Sheath, HUMORS) auf drei unterschiedlichen Scaffolds getes-tet. Hinsichtlich mitochondrialer Aktivität (Marker für Zellproliferation), mela-nozytenspezifischer Markerexpression und ihrer Funktionalität (Tyrosinase-Enzymaktivität und Melaningehalt) wurden die Zellen auf Collagen Cell Carrier® (CCC), Poly-ε-Caprolacton-Scaffolds (PCL) und kollagen basierten Hydrogelen (cGEL) kultiviert und charakterisiert. Alle Scaffolds waren biokompatibel, immu-nologisch nur gering aktiv und wiesen eine dreidimensionale Struktur auf, die der extrazellulären Matrix nachempfunden war. Einen positiven Effekt auf die Prolife-ration wiesen die HUMORS auf den Collagen Cell Carrier® auf. Bei Untersuchun-gen der melanotischen Aktivität überzeugten die HUMORS auf dem cGEL Typ4 durch einen signifikant höheren Melaningehalt. Da Melanin das entscheidende Produkt der Repigmentierung bei Vitiligoläsionen ist, stellte sich damit das cGEL Typ4 als vielversprechender Zellträger für die Kultivierung und vorgesehene Transplantation der Melanozyten heraus.

Title: Correlation properties of magnetosheath fluctuations Author: Olga Gutynska Department: Department of Surface and Plasma Science Supervisor: Prof. RNDr. Jana Šafránková, DrSc. e-mail address: Jana.Safrankova@mff.cuni.cz Abstract: This thesis deals with fluctuations of the magnetic field (MF) and plasma density in different magnetosheath locations. The statistical study of the correlation length of these quantities has shown that these lengths are surprisingly low for both the ion flux and MF (approx. 1 RE). However, the correlation length increases with an increasing correlation between the magnetosheath and interplanetary magnetic fields (IMF). Further, we have found that the correlation length of MF fluctuations depends on the solar wind speed, on a correlation between IMF and magnetosheath MF fluctua- tions, and on the amplitude of fluctuations. The statistical study of radial profiles of cross-correlations between MF and plasma density at the subsolar and flank regions based on Cluster and THEMIS magnetosheath observa- tions revealed better correlations toward the magnetopause. A study of the modification of the IMF direction in the magnetosheath has shown that a reliable prediction of the magnetosheath BZ sign requires |IMF BZ| > 2 nT and that this prediction is more precise during solar minimum....

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Traumatic brain injury (TBI) affects millions of people worldwide, leading to significant mortality and disability rates. Elevated intracranial pressure (ICP) resulting from TBI can cause severe complications and requires early detection to improve patient outcomes. While invasive methods are commonly used to measure ICP accurately, non-invasive techniques such as optic nerve sheath diameter (ONSD) measurement show promise. This study aims at the creation of a tool that can automatically perform a segmentation of the ONS from a head computed tomography (CT) scan, and extracts meaningful measures from the segmentation mask, that can be used by radiologists and medics when treating people affected by TBI. This has been achieved using a deep learning model called ”nnU-Net”, commonly adopted for semantic segmentation in medical contexts. The project makes use of manually labeled head CT scans from a public dataset named CQ500, to train the aforementioned segmentation model, using an iterative approach. The initial training using 33 manually segmented samples demonstrated highly satisfactory segmentations, with good performance indicated by Dice scores. A subsequent training, combined with manual corrections of 44 unseen samples, further improved the segmentation quality. The segmentation masks enabled the development of an automatic tool to extract and straighten optic nerve volumes, facilitating the extraction of relevant measures. Correlation analysis with a binary label indicating potential raised ICP showed a stronger correlation when measurements were taken closer to the eyeball. Additionally, a comparison between manual and automated measures of optic nerve sheath diameter (ONSD), taken at a 3mm distance from the eyeball, revealed similarity between the two methods. Overall, this thesis lays the foundation for the creation of an automatic tool whose purpose is to make faster and more accurate diagnosis, by automatically segmenting the optic nerve and extracting useful prognostic predictors. / Traumatisk hjärnskada (TBI) drabbar miljontals människor över hela världen, vilket leder till betydande dödlighet och funktionshinder. Förhöjt intrakraniellt tryck (ICP) till följd av TBI kan orsaka allvarliga komplikationer och kräver tidig upptäckt för att förbättra patientens resultat. Medan invasiva metoder vanligtvis används för att mäta ICP exakt, icke-invasiva tekniker som synnervens höljediameter (ONSD) mätning ser lovande ut. Denna studie syftar till att skapa ett verktyg som automatiskt kan utföra en segmentering av ONS från en datortomografi skanning av huvudet, och extraherar meningsfulla åtgärder från segmenteringsmasken, som kan användas av radiologer och läkare vid behandling av personer som drabbats av TBI. Detta har uppnåtts med hjälp av en deep learning modell som kallas ”nnU-Net”, som vanligtvis används för semantisk segmentering i medicinska sammanhang. Projektet använder sig av manuellt märkta datortomografi skanningar från en offentlig datauppsättning som heter CQ500, för att träna den tidigare nämnda segmenteringsmodellen, med hjälp av en iterativ metod. Den inledande träningen med 33 manuellt segmenterade prov visade tillfredsställande segmentering, med god prestation indikerad av Dice-poäng. En efterföljande utbildning, i kombination med manuella korrigeringar av 44 osedda prover, förbättrade segmenteringskvaliteten ytterligare. Segmenteringsmaskerna möjliggjorde utvecklingen av ett automatiskt verktyg för att extrahera och räta ut optiska nervvolymer, vilket underlättade utvinningen av relevanta mått. Korrelationsanalys med en binär märkning som indikerar potentiellt förhöjd ICP visade en starkare korrelation när mätningar gjordes närmare ögongloben. Dessutom avslöjade en jämförelse mellan manuella och automatiserade mätningar av optisk nervmanteldiameter (ONSD), tagna på ett avstånd på 3 mm från ögongloben, likheten mellan de två metoderna. Sammantaget lägger denna avhandling grunden för skapandet av ett automatiskt verktyg vars syfte är att göra snabbare och mer exakta diagnoser, genom att automatiskt segmentera synnerven och extrahera användbara prognostiska prediktorer.

Bone transplantation is regarded as the preferred therapy to treat a variety of bone defects. Autologous bone tissue is often lacking at the source, and the mesenchymal stem cells (MSCs) responsible for bone repair mechanisms are extracted by invasive procedures. This study explores the potential of autologous mesenchymal stem cells derived from the hair follicle outer root sheath (MSCORS). We demonstrated that MSCORS have a remarkable capacity to differentiate in vitro towards the osteogenic lineage. Indeed, when combined with a novel gelatin-based hydrogel called Osteogel, they provided additional osteoinductive cues in vitro that may pave the way for future application in bone regeneration. MSCORS were also compared to MSCs from adipose tissue (ADMSC) and bone marrow (BMMSC) in a 3D Osteogel model. We analyzed gel plasticity, cell phenotype, cell viability, and differentiation capacity towards the osteogenic lineage by measuring alkaline phosphatase (ALP) activity, calcium deposition, and specific gene expression. The novel injectable hydrogel filled an irregularly shaped lesion in a porcine wound model displaying high plasticity. MSCORS in Osteogel showed a higher osteo-commitment in terms of calcium deposition and expression dynamics of OCN, BMP2, and PPARG when compared to ADMSC and BMMSC, whilst displaying comparable cell viability and ALP activity. In conclusion, autologous MSCORS combined with our novel gelatin-based hydrogel displayed a high capacity for differentiation towards the osteogenic lineage and are acquired by non-invasive procedures, therefore qualifying as a suitable and expandable novel approach in the field of bone regeneration therapy