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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
321

Incorporating primary human renal proximal tubule cells into a hollow fibre bioreactor in the development of an in vitro model for pharmaceutical research

Ginai, Maaria January 2015 (has links)
Current in vitro cellular methods utilised in drug metabolism and pharmacokinetic (DMPK) studies during drug development do not provide the 3D structure and functions of organs found in vivo, such that resulting in vitro-in vivo extrapolation (IVIVE) may not always accurately reflect clinical outcome. This highlights the need for the development of new dynamic in vitro cell models to aid improvement of IVIVE. The aim of this project was to incorporate characterised primary renal cells within a hollow fibre bioreactor for use in DMPK studies investigating renal clearance. Fluorescence based assays were developed to assess the functionality of three drug transporters involved in the renal transport of pharmaceutical compounds: P-gp, BCRP and OCT2. The developed assays were then applied alongside transporter visualisation and genetic expression assays to characterise primary human proximal tubule cells over a series of population doublings. Cells at a population doubling of 5 demonstrated the best transporter activity whilst allowing cells to be expanded in vitro. Polysulfone (PSF) based membranes, which are widely used in dialysis components were developed by blending additives to improve renal cell attachment and culture. The membranes exhibited a characteristic porous internal structure with smooth skin layers on the surface, and were able to be sterilised via autoclaving due to their high thermal stability. PSF blended with polyvinylpyrrolidone (PVP) was the most hydrophilic with cell metabolic activity similar to standard tissue culture plastic. The production of hollow fibres of varying thicknesses and properties from the PSF and PVP blend yielded a marked difference in renal cell attachment and long term viability. Fibres incorporated into glass casings to produce the single hollow fibre bioreactors (HFBs) were able to be sterilised by autoclaving whilst remaining intact. Due to the variation of fibre integrity within the batch, many fibres exhibited tears within the HFBs. This ultimately led to cell depletion within the fibre over the culture period; however, intact fibres demonstrated an increase in cell growth towards the end of the culture period under flow conditions. These results demonstrate the progress made towards a small scale in vitro renal model incorporating characterised primary renal cells to aid the improvement of IVIVE in DMPK research.
322

The perceptions of intermediate phase educators about the implementation of stories for thinking in one Western Cape Education Department region

Agulhas, Ronald January 2011 (has links)
Magister Educationis - MEd / South Africa had a change in government and in education after the 1994 elections. A new curriculum was introduced and some of the underlying critical outcomes were to develop the learners to become critical thinkers. The methodology by which to teach these outcomes was not clear. An intervention programme, Philosophy for Children (P4C) is used in some countries across the world to promote thinking. Research across the world has shown that this programme has the ability to enhance the cognitive abilities of learners exposed to it. Stories for Thinking (SFT) is an intervention programme based on the principles of Philosophy for Children and was introduced in some schools in an Education District of the Western Cape. This study investigates the perceptions of Intermediate Phase educators about the implementation of Stories for Thinking in this Education District. Educators were asked their strengths and challenges of the approach, their way of using it and the support they received. A qualitative research method was used and data were gathered to answer the research questions by means of questionnaires and interviews. Research findings indicate that educators perceived that Stories for Thinking was able to enhance the reading ability of the learners, it showed a significant improvement in their confidence levels, and a positive change in their general behaviour. Language was seen as a barrier to learning, but the evidence indicates that the community of inquiry can be used as a tool to overcome some of the barriers. It seems as if educators valued the support from the project leaders. It is concluded that this kind of intervention programme is worth introducing as long as all the role-players play their part and the setting is conducive. / South Africa
323

Skilda Världar : Lärares och elevers skilda uppfattningar om motivation

Sembrant, Jennifer January 2020 (has links)
Studiens syfte var att försöka förstå fenomenet motivation genom att undersöka hur några elever upplever motivation och hur några lärare uppfattar elevers motivation. Eleverna som deltog i studien studerade naturbruksprogrammet på en gymnasieskola i Mellansverige och lärarna som deltog i studien arbetade på samma skola. Studien var en fallstudie och metodiken som användes var Critical Incident Technique (CIT) och insamlingsmetoden gruppintervju. Det insamlade materialet bestod av sju lärares beskrivningar av kritiska händelser och fem elevers beskrivningar av kritiska händelser. Materialet samlades in vid tre tillfällen under hösten 2019. Undersökningen gick ut på att utifrån lärares och elevers beskrivningar av händelser, sortera och kategorisera utsagorna för att kunna urskilja hur motivation och omotivation uppstått i de beskrivna händelserna. Teorierna som används för att sortera och kategorisera det insamlade materialet var Self-Determinant Theory, Zone of Proximal Development och KASAM. Resultatet visade att lärares uppfattning av elevers motivation skiljer sig från elevers upplevda motivation. När lärare uppfattar elevers motivation som inre motivation beskriver elever att det handlar om yttre motivation. Dessutom visar resultatet vikten av att känna meningsfullhet, förståelse och vikten av lärarens stöttning i förhållande till elevers utvecklingsnivå.
324

Espectroscopia de reflectância do visível ao infravermelho médio aplicada aos estudos qualitativos e quantitativos de solos / Reflectance spectroscopy from visible to mid-infrared applied for qualitative and quantitative studies of sois

Terra, Fabricio da Silva 09 February 2012 (has links)
Com a intensificação e expansão da produção agrícola brasileira, seguidas da crescente preocupação ambiental, surge a necessidade da adoção de novas tecnologias para o monitoramento e avaliação em larga escala dos recursos naturais, em especial o solo. Nesse sentido a espectroscopia de reflectância, aliada as bibliotecas espectrais, atende estas expectativas por ser uma técnica eficiente, rápida, barata e não poluente, pois não usa reagentes e nem gera resíduos, porém sua aplicação nos solos tropicais brasileiros ainda é incipientes e carece de mais estudos. Sendo assim, o objetivo principal do trabalho foi comparar as informações espectrais obtidas por espectroscopia de reflectância nas faixas do visível, infravermelho próximo e, principalmente, no infravermelho médio com análises convencionais de solo a fim entender as relações existentes entre o comportamento espectral e os atributos físicos, químicos e mineralógicos dos solos estudados, ainda quantificar e caracterizar a variabilidade desses atributos e dos solos com base no comportamento espectral. Para tanto, foram utilizadas 1288 amostras de solo correspondentes a diferentes horizontes de 458 perfis da região central brasileira (GO, MS, MG e SP), sobre as quais foram procedidas análise granulométrica e química, para fins de levantamento de solos, e mineralógica. Os espectros VisNIR foram adquiridos com o sensor FieldSpec Pro, enquanto que espectros Mid-IR com o sensor Nicolet 6700 Fourier Transform Infrared (FT-IR) e, após isso, os dados foram transformados com os seguintes préprocessamentos: remoção do espectro contínuo, absorbância e correção da linha base. As diferentes faixas espectrais também foram combinadas pela outer product analysis. A distribuição dos dados espectrais e a influência de cada atributo nos comportamentos espectrais dos solos foram avaliadas através de análises estatísticas multivariadas, tais como correlação multivariada, análise por componentes principais, seguidas das análises de agrupamento kmédias, para a avaliação entre amostras, e distância taxonômica, para avaliação entre perfis. A predição dos atributos dos solos com base nos dados espectrais foi determinada pelos algoritmos de regressão multivariada: mínimos quadrados parciais (PLSR), árvores de regressão ampliadas (BT) e máquina de vetor suporte (SVM); sendo que a qualidade das predições foi definida pelos R2, RMSE, RPD e RPIQ. O comportamento espectral das principais classes de solos tropicais brasileiros, em ambas as faixas espectrais, foi apresentado juntamente com as principais feições de absorção diagnosticadas (minerais 2:1, caulinita, óxidos de Fe e Al), assim como a contribuição de cada atributo do solo na variação dos espectros. Foi possível estabelecer a formação de grupos de solo com base no grau de intemperismo das amostras, enquanto que os perfis das principais classes de solos puderam ser discriminados com base na variação do comportamento espectral em profundidade. Grande parte dos atributos estudados pode ser quantificada nas duas faixas espectrais pelo menos com um nível de qualidade razoável (RPD > 1,40), sendo que o principal algoritmo de predição foi o SVM com os espectros em valores de absorbância. A espectroscopia de reflectância, principalmente na faixa Mid-IR, apresenta-se como uma tecnologia eficaz de alta potencialidade e aplicabilidade nas análises qualitativa e quantitativas dos solos, principalmente para fins de levantamento e mapeamento. / Considering the intensification and expansion of Brazilian agricultural production followed by the growing environmental concern, there is the necessity of adopting new technologies to monitor on a large scale the natural resources, in particular, the soil. In this sense, reflectance spectroscopy, integrated with spectral libraries, meets that expectation as an alternative for proximal soil sensing because its more efficient than other techniques being cheaper and faster than conventional analyses, besides, it doesnt produce waste. However, its application on Brazilian tropical soils is still incipient and needs more studies. The main aim of this research was to compare spectral information acquired by reflectance spectroscopy in the visible, near infrared and, mainly, in the mid infrared ranges with conventional soil analyses in order to understand the relationships among spectral behavior and physical, chemical, and mineralogical attributes of the studied soils, also, to quantify and characterize the variability of these attributes and soils based on their spectral behavior. For that, a dataset with 1288 soil samples referring to different horizons from 458 soil profiles from the central region of Brazil (States of Goiás, Mato Grosso do Sul, Minas Gerais e São Paulo) was used, and convetional analyses (granulometric, chemical and mineralogical) for soil survey were applied over them. VisNIR reflectance data were acquired by the FiledSpec Pro sensor whereas Mid-IR spectral data were acquired by the Nicolet 6700 (FT-IR) sensor and, after that, both data were transformed by the following pre-processing: continuum removal, absorbance and baseline correction. The different spectral ranges were also combined by outer product analysis. The data distribution and the influence of each attribute on soil spectral behavior were evaluated by multivariate statistical analyses, such as, multivariate correlations, principal component analysis followed by k-means clustering, for assessment among soil samples, and by taxonomic distance, for assessment among soil profiles. Predictions of soil attributes based on spectral data were modeled by following multivariate regression algorithms: partial least square regression (PLSR), boosted regression trees (BT) and support vector machine (SVM) and quality of modeling were evaluated by R2, RMSE, RPD and RPIQ. Spectral behavior of the main soil classes, in both ranges, were showed along with the absorption features of the major tropical minerals (2:1 minerals, kaolinite, Fe and Al oxides), as well as, the contribution of each soil attribute on spectra variations. Sample clustering based on different weathering levels of soils was possible regarding differences in absorbance intensities and features whereas profiles of the main soil classes could be discriminated based on variation of spectral behavior in depth. Much of the studied attributes could be predicted in both spectral range at least in a reasonable level of quality (RPD > 1,40), and SVM was considered the principal prediction algorithm as well as absorbance transformation as the major pre-processing. Reflectance spectroscopy, especially in the Mid-IR range, shows up as a high potential technique for qualitative and quantitative analysis of Brazilian soils, in particular for soil survey or mapping.
325

Der Einfluss von Therapie und Prophylaxe mit Strontiumranelat auf das proximale Femur osteoporotischer Ratten / The influence of therapy and prophylaxis with strontium ranelate on proximal femur of osteoporotic rats

Köstner, Felix 04 February 2020 (has links)
No description available.
326

Paralelizace náročných úloh rekonstrukce v dynamické magnetické rezonanci / Parallelization of complex tasks in reconstruction of dynamic magnetic resonance

Bijotová, Kateřina January 2019 (has links)
This thesis deals with parallelization of complex tasks in reconstruction of dynamic magnetic resonance. It describes the basic principle of magnetic resonance and its relation to Fourier transform. It deals with the difference between static and dynamic magnetic resonance image reconstruction. It analyzes SVD algorithm and its use in magnetic resonance image reconstruction. It presents the principles and the importance of parallel computing in magnetic resonance imaging and describes CUDA technology. The thesis also contains a description and execution of the implementation of the reconstruction model in MATLAB and Java programming language which were optimized by JCuda library for Java implementation and gpuArray function in case of MATLAB implementation.
327

Paralelizace náročných úloh rekonstrukce v dynamické magnetické rezonanci / Parallelization of complex tasks in reconstruction of dynamic magnetic resonance

Bijotová, Kateřina January 2019 (has links)
This thesis deals with parallelization of complex tasks in reconstruction of dynamic magnetic resonance. It describes the basic principle of magnetic resonance and its relation to Fourier transform. It deals with the difference between static and dynamic magnetic resonance image reconstruction. It analyzes SVD algorithm and its use in magnetic resonance image reconstruction. It presents the principles and the importance of parallel computing in magnetic resonance imaging and describes CUDA technology. The thesis also contains a description and execution of the implementation of the reconstruction model in MATLAB and Java programming language which were optimized by JCuda library for Java implementation and gpuArray function in case of MATLAB implementation.
328

Pokročilé optimalizační algoritmy a jejich efektivní implementace / Efficient Implementation of Advanced Optimization Algorithms

Talpa, Jaroslav January 2020 (has links)
Tato diplomová práce se zabývá tématikou konvexní optimalizace a to konkrétně modifikacemi algoritmu ADMM, společně s problematikou proximálních operátorů. Jedna z verzí ADMM je pak implementována v programovacím jazyce Julia s důrazem na obecnost a efektivnost této implementace, a dále aplikována na rozsáhlou úlohu z oblasti odpadového hospodářství.
329

Biomechanická studie proximální části femorálního vnitrodřeňového hřebu / Biomechanical study of the proximal part of the femoral intermedullary nail

Hrdlička, Jan January 2015 (has links)
The presented Master Thesis is focused on the structural analysis of the proximal femur on which the Proximal Femoral Nail (PFN) and Proximal Femoral Tele-Screw (PFT) systems are applied. These systems are used for a treatment of the intertrochanteric and femoral neck fractures. However, in some cases a loss of stability of the systems may be expected. The presented thesis describes a development of numerical models in which stress distribution of implants and strain distribution of bone tissue are compared. Numerical models were created from real objects. The model of femur geometry was created by using the Computed Tomography (CT). Boundary conditions of the model were estimated from the force equilibrium of the lower limb. All numerical models were processed in the commercial package ANSYS Workbench v15.0. It is shown that the hip screws of the PFN system result in lower equivalent stresses than the screws of the PFT system. Maximal strains of the bone tissue, when using the PFN system, are situated near the fracture, close the hip screw thread. For the PFT system, the maximal strains are only near the area of fracture.
330

Doplňování chybějících vzorků v audio signálu / Inpainting of Missing Audio Signal Samples

Mach, Václav January 2016 (has links)
V oblasti zpracování signálů se v současné době čím dál více využívají tzv. řídké reprezentace signálů, tzn. že daný signál je možné vyjádřit přesně či velmi dobře aproximovat lineární kombinací velmi malého počtu vektorů ze zvoleného reprezentačního systému. Tato práce se zabývá využitím řídkých reprezentací pro rekonstrukci poškozených zvukových záznamů, ať už historických nebo nově vzniklých. Především historické zvukové nahrávky trpí zarušením jako praskání nebo šum. Krátkodobé poškození zvukových nahrávek bylo doposud řešeno interpolačními technikami, zejména pomocí autoregresního modelování. V nedávné době byl představen algoritmus s názvem Audio Inpainting, který řeší doplňování chybějících vzorků ve zvukovém signálu pomocí řídkých reprezentací. Zmíněný algoritmus využívá tzv. hladové algoritmy pro řešení optimalizačních úloh. Cílem této práce je porovnání dosavadních interpolačních metod s technikou Audio Inpaintingu. Navíc, k řešení optimalizačních úloh jsou využívány algoritmy založené na l1-relaxaci, a to jak ve formě analyzujícího, tak i syntetizujícího modelu. Především se jedná o proximální algoritmy. Tyto algoritmy pracují jak s jednotlivými koeficienty samostatně, tak s koeficienty v závislosti na jejich okolí, tzv. strukturovaná řídkost. Strukturovaná řídkost je dále využita taky pro odšumování zvukových nahrávek. Jednotlivé algoritmy jsou v praktické části zhodnoceny z hlediska nastavení parametrů pro optimální poměr rekonstrukce vs. výpočetní čas. Všechny algoritmy popsané v práci jsou na praktických příkladech porovnány pomocí objektivních metod odstupu signálu od šumu (SNR) a PEMO-Q. Na závěr je úspěšnost rekonstrukce poškozených zvukových signálů vyhodnocena.

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