Thesis (doctoral)--University of Göteborg, Sweden, 1981. / Includes bibliographical references.

Thesis (M.S.)--University of Michigan, Ann Arbor, 1970. / Typescript (photocopy). eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 45-49).

Thesis (doctoral)--University of Göteborg, Sweden, 1981. / Includes bibliographical references.

Thesis (Ph. D.)--University of Wisconsin--Madison, 1951. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 103-104).

Thesis (Ph. D.)--University of Wisconsin--Madison, 1943. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 59-62).

Thesis (doctoral)--Freie Universität Berlin, 1980.

Thesis (M.S.)--University of Wisconsin--Madison, 1966. / eContent provider-neutral record in process. Description based on print version record. Bibliography: l. 67-72.

Orientador: Marisa Masumi Beppu / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Quimica / Made available in DSpace on 2018-08-13T20:01:56Z (GMT). No. of bitstreams: 1 Weska_RaquelFarias_M.pdf: 2528542 bytes, checksum: c7faca11cd121664f82f4719ad8f66fd (MD5) Previous issue date: 2009 / Resumo: A fibroína de seda tem sido amplamente explorada para aplicações biomédicas, devido à sua biocompatibilidade, biodegradabilidade e mínima reação inframatória. A esterilização é uma etapa fundamental no processamento de biomateriais, e não deve alterar de forma negativa as propriedades funcionais dos dispositivos médicos. Estudos recentes verificaram que a fibroína pode ser utilizada como suporte para mimetizar a biomineralização, promovendo o crescimento de cristais de hidroxiapatita. O objetivo deste trabalho foi analisar a influência de diferentes métodos de esterilização nas características físicas, mecânicas e biológicas de membranas densas e porosas de fibroína de seda, e também estudar a possibilidade de aplicação de membranas de fibroína como biomaterial, pelo estudo da calcificação in vitro. Membranas densas e porosas de fibroína foram esterilizadas por radiação ultravioleta, etanol 70%, autoclave, óxido de etileno e radiação gama, e foram analisadas por MEV, FTIR-ATR, DRX, testes mecânicos e de citotoxicidade indireta. Para os ensaios de calcificação in vitro, as membranas de fibroína foram imersas em SBF por sete dias, e caracterizadas por MEV e EDX. Os resultados de esterilização mostraram que nenhum método ocasionou degradação das membranas ou a formação de produtos citotóxicos. Os métodos que utilizaram solvente orgânico, e aumento de umidade e/ou temperatura (etanol 70%, autoclave e óxido de etileno) tornaram as membranas densas mais cristalinas, e as membranas porosas mais estáveis, o que pode ser aproveitado quando se deseja que as membranas apresentem uma degradação in vivo mais lenta, dependendo da aplicação. Os resultados obtidos de calcificação in vitro indicaram que a fibroína pode induzir a calcificação, pela formação de depósitos de fosfato de cálcio com relações de Ca/P similares à da hidroxiapatita e seus precursores. A membrana porosa apresentou maior tendência à calcificação, quando comparada com a membrana densa, devido à sua rugosidade e porosidade, podendo desta forma ser considerada para aplicação em regeneração óssea. / Abstract: Silk fibroin has been widely explored for many biomedical applications, due to its biocompatibility, biodegradability and minimal inflammatory reactions. Sterilization is a fundamental step in biomaterials processing, and it must not alter in a negative way the functionality of medical devices. On the applicability of fibroin as a biomaterial, recent studies verified that fibroin can be used as a scaffold for mimicking biomineralization, promoting the growing of hydroxyapatite crystals. The aim of this study was to analyze the influence of different sterilization methods on physical, mechanical and biological characteristics of dense and porous silk fibroin membranes, and also to study the application of the fibroin membranes as biomaterials, through in vitro calcification studies. Dense and porous fibroin membranes were sterilized by ultraviolet radiation, 70% ethanol, autoclave, ethylene oxide and gamma radiation, and were analyzed by SEM, FTIR-ATR, XRD, mechanical and cytotoxicity tests. For in vitro calcification experiments, the fibroin membranes were soaked in SBF for seven days, and characterized by SEM and EDS. The results for sterilization indicated that none of the methods caused degradation or formation of cytotoxic substances. The methods that used organic solvent, and increase of humidity and/or temperature (70% ethanol, autoclave and ethylene oxide) increased the crystallinity of the dense membranes, and stabilized the porous membranes, characteristics that may be utilized when a slow in vivo degradation is desired, depending on the application. The calcification experiments indicated that silk fibroin may induce calcification, by forming calcium phosphate deposits with a Ca/P ratio similar to that of hydroxyapatite and its precursors. Porous membranes presented higher tendency to calcify, when compared to dense membranes, due to its surface roughness and high porosity, indicating that porous silk fibroin membranes may be considered for application in bone regeneration. / Mestrado / Engenharia de Processos / Mestre em Engenharia Química

Doctor Educationis / The need for in-depth knowledge of dental emergence and calcification in orthodontic diagnosis and treatment planning cannot be disputed. Serial extractions, treatment timing, bite opening and closing, expansion and various other orthodontic procedures cannot be successfully executed without an in depth knowledge of the calcification and eruption of teeth. Besides its orthodontic implications, dental calcification and eruption plays a significant role in physical anthropology, forensic odontology, endocrinology and nutrition (Demirjian, 1978). Forensic scientists are agreed that teeth constitute the most important and reliable means for determining age from approximately 10 week in utero to old age (Altini, 1983). It is a generally accepted fact that there is no correlation between biological age and chronological age (Prahl-Andersen and Van der Linden, 1972; Demirjian, 1978), an aspect, which will be discussed in further detail later in the review of the literature. Biological age is seen to be a more accurate indicator of an individuals maturity than chronological age (Moorees et al, 1963; Prahl-Andersen and Van der Linden, 1973; Oemirjian et al, 1973). However, allocating a biological age to an individual is not an easy exercise as no definite consensus has, to date, been reached regarding the best method of determining biological age (Moorees et al, 1963; Garn et al, 1967; Demirjian, 1978). Today, many different methods are being used to establish this, for example bone age, height, menarche, circumpubertal growth and dental age.

Medial calcification refers to mineral deposition in the middle layer of arteries. This mineralization is common in chronic kidney disease patients and causes an increased chance of cardiovascular complications. Calcitriol, the active form of vitamin D, is often administered to these patients to treat an associated condition, secondary hyperparathyroidism. Unfortunately, calcitriol treatment may promote vascular calcification due to increasing serum calcium and phosphate. We examined the effects of calcitriol supplementation on vascular smooth muscle cell (VSMC) calcification, through atomic absorption, scanning electron microscopy, and western blot analysis. Additionally, we examined the effects of the combinations of calcitriol, fibroblast growth factor 23 (FGF-23), and klotho. We determined that calcitriol supplementation alone increased calcification but was not associated with a transition towards an osteoblast-like phenotype. On the other hand, the combination of calcitriol and FGF-23 caused a decrease in calcification, but this decrease was attenuated with the further addition of klotho.