This thesis researches in the structure and fabrication of lensed fibers. To begin with, a novel method for automating fiber endface polishing to form quadrangular-pyramid-shaped fiber endface (QPSFE)-like shape is presented. This system successfully supported automatic polishing with an encouraged fiber tip offset. Such an automatic polishing system can also be applied to any other type of fiber endface. Next, an advanced polishing method to form an elliptical microlens endface from a QPSFE-like shape fiber is proposed. There are many advantages of this approach. First, the process to remove the tip of the fiber can be omitted and be replaced by the proposed process. This would raise the yield of the manufacturing of the lensed fiber and reducing manufacturing time and eliminating the possibility of human error. Second, after the process of the proposed method, an elliptic microlens is formed on the end of fiber and the fusing step can be skipped. In addition, in optical module packaging, laser welding used to attach components is expected to cause relative motion between the pre-aligned components. Such shifts might considerably reduce the efficiency of light coupling. This thesis provides a particular method to measurement the fiber shifts along the three axes quickly and precisely. Furthermore, the efficient coupling of plastic optical fibers (POFs) to the light source has become critical. Two kinds of new schemes of lensed optical fiber for POFs are proposed. The first type of lensed plastic optical fiber (LPOF) scheme is fabricating a convexo-concave-shaped fiber endface (CCSFE) by joining a flat-end POF and a convexo-concave plastic lens (CCPL). The second type of LPOF scheme is fabricating a hyperbola shape LPOF by using electrical force. Both designs of the LPOF all have advantages of easy fabrication and automatic manufacture.

Submitted by Luiz Felipe Barbosa (luiz.fbabreu2@ufpe.br) on 2015-03-10T18:07:47Z No. of bitstreams: 2 DISSERTAÇÃO Roberto Tenorio Figueiredo.pdf: 4777817 bytes, checksum: cf990f731142ef8b52d6cff5757837f7 (MD5) license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) / Made available in DSpace on 2015-03-11T17:39:22Z (GMT). No. of bitstreams: 2 DISSERTAÇÃO Roberto Tenorio Figueiredo.pdf: 4777817 bytes, checksum: cf990f731142ef8b52d6cff5757837f7 (MD5) license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) Previous issue date: 2014-03-14 / No contexto de um mercado cada vez mais exigente e competitivo, as empresas desenvolvedoras de jogos têm adotado bibliotecas e frameworks para realizar funções básicas (como detectar dispositivos de entrada, acessar interfaces de hardware, renderizar imagens, etc.), ganhando tempo e deixando o programador mais focado na lógica do jogo. Neste contexto, a utilização de padrões de projeto poderia ser mais uma ferramenta importante para auxiliar o desenvolvimento de jogos. Infelizmente, ainda há poucos trabalhos devotados a catalogar padrões de projetos em jogos. Um grupo bastante afamado de padrões de projeto é o GoF (Gang of Four), composto por vinte e três padrões com uso reconhecido em aplicações comerciais, mas com utilização bastante limitada no desenvolvimento de jogos. Este trabalho analisa alguns padrões de projeto propostos para o desenvolvimento jogos e propõe maneiras de se utilizar todos os padrões GoF neste contexto, não somente mostrando o resultado final, mas apresentado o “antes e depois” da aplicação desses padrões e onde eles estão auxiliando o programador em sua tarefa. Uma avaliação preliminar do uso destes padrões nos jogos foi positiva.

The tumour suppressor p53 is often disrupted by missense mutations that can result in p53 protein accumulation and acquisition of novel oncogenic activities. Various studies have demonstrated that DNA-damaging drugs currently used in the clinic aimed at activating wild type p53, can also stabilise and activate mutant p53 oncogenic functions and thereby paradoxically enhance tumour progression, resulting in poor response to the treatment. In this study we aimed to investigate whether, like in wt p53, post-translational modifications (PTMs) drive such drug-induced mutant p53 accumulation and activation. For this purpose, we generated plasmids expressing non-phosphorylatable and phospho-mimic versions of R175H mutant p53 and tested them in different cell line models. We demonstrated that in response to DNA damage mutant p53 is accumulated and phosphorylated and these phenomena appeared to be mediated by ATM and ATR kinases. DNA-damage induced acetylation was also observed and occurred in a S15 phosphorylation-dependent manner. This suggested a role of the HAT p300, which is recruited by phosphorylated S15. Of note, other works have shown that p300 is required to trigger some oncogenic functions of mutant p53. We then aimed at developing systems to explore mutant p53 functions and their dependence on PTMs. Although we showed that cell growth is compromised upon endogenous mutant p53 depletion, exogenous expression of mutant p53 or its phosphorylation-site forms did not result in a successful rescue in our experimental conditions, thus we were unable to use this strategy to test the effect of PTMs. Ectopic expression of R175H mutant p53 or its phosphorylayion-site versions did not interfere with the growth rate and response to chemotherapy of the p53-null cell line H1299. We also found that mutant p53 phosphorylation does not affect subcellular localisation of mutant p53 and mutant p53-mediated inhibition of p63. Interestingly, ectopically expressed mutant p53 enhanced cell migration in H1299 cells. Notably, our results suggested an apparent threshold effect of mutant p53 levels required to induce migration. Due to the difficulty of obtaining cell lines expressing similar levels of the different phosphorylation-site mutants, the determination of the role of phosphorylation in mutant p53-induced migration was not conclusive. Remarkably, we found that, while S15 and S20 phosphorylation decreased MDM2-dependent degradation, only phosphorylated S20 interfered with CHIP-induced turnover in H1299 cells. Overall our data suggest that, despite exhibiting opposite biological effects, mutant and wt p53 can share upstream regulatory mechanisms and thus present phosphorylation as a promising target to prevent mutant p53 stabilisation and activation and improve response to therapy. Our results also highlight the challenge of developing a good system for determining the effects of the mutant p53 protein and its regulation by PTMs.

L’osteopetrosi autosomale recessiva (ARO) è un gruppo di malattie dovute a un difettoso funzionamento degli osteoclasti che preclude un rimodellamento osseo corretto. Nel 50% dei casi umani il difetto è dovuto ad una delezione nel gene Tcirg1. Il modello murino mutante oc/oc porta lo stesso difetto genetico e fenotipico umano. Nel lavoro di tesi si è dimostrato che gli epatociti fetali di 12.5 giorni di gestazione trapiantati in utero in feti mutati di 13.5 giorni di gestazione sono in grado di curare il fenotipo malato. Si è inoltre derivata una sottolinea di cellule staminali embrionali murine transgeniche per il costrutto plasmidico GOF18eGFP. Si vuole utilizzare la GFP sotto il controllo del promotore del gene Oct-4 come marcatore del livello di staminalità cellulare per microiniettare le ESC in blastocisti murine mutate oc/oc. / Autosomal recessive osteopetrosis (ARO) is a group of genetic disorders due to defects that preclude normal function of osteoclasts. In half the cases, human ARO is due to mutations in the Tcirg1 gene. The oc/oc mutant mouse closely recapitulates human Tcirg1-dependent ARO. In ths work we demonstrate that in utero injection of allogenic fetal liver cells on 12.5 days into oc/oc fetuses at 13.5 day post coitum completely rescue the osteopetrotic phenotype. Moreover, an embryonic stem cells line transgenic for GOF18eGFP was produced. The goal is to use the GFP under the transcriptional control of the Oct-4 promoter as a marker of pluripotency of the ESC that are to microinject into oc/oc blastocysts.