Thesis (Ph.D.)--University of Alabama at Birmingham, 2008. / Title from PDF title page (viewed on July 15, 2010). Includes bibliographical references.

Dissertation (Ph.D.).--University of Texas Graduate School of Biomedical Sciences at San Antonio, 2007. / Vita. Includes bibliographical references.

Ultrastructural observations on the six-day chick embryo lens reveal that fibre cell differentiation, which involves extensive cell elongation, is characterized by the presence of numerous oriented microtubules and by marked changes in intercellular relationships which are felt to be important for cell extension. Increased Golgi activity in cells initiating elongation appears to be related to the formation of intercellular junctions and the elaboration of new surface membrane. Studies concerning the differentiation in vitro of anterior lens epithelia demonstrate that their cells elongate either to a great extent or to a limited extent, depending on factors deriving from the epithelial conformation.The conformation of an explanted anterior lens epithelium can be manipulated so that its cells elongate consistently to either a limited or a great extent. These cells, whether elongated to a limited or to a great extent, are ultrastructurally similar with respect to features reflecting cytoplasmic differentiation, including those important for morphogenesis. Their fine structure closely resembles that of fibre cells differentiating in vivo. The cells of anterior lens epithelia differentiating in vitro, whether elongating to a limited or to a great extent, are the same in terms of the nature and relative proportions of their soluble proteins as indicated by polyacrylamide gel electrophoresis. There is a change in the relative proportions of the soluble proteins accumulated by the anterior lens epithelia when they differentiate in vitro that is similar to that which occurs in cells undertaking fibre cell differentiation in vivo. It is concluded that those factors deriving from the conformation of the anterior lens epithelium that affect the degree of elongation of its cells differentiating in vitro are physical in nature. Since such physical factors are important with regard to restraining or encouraging the expression of morphogenetic potential in vitro, it is suggested that similar physical forces are important in lens morphogenesis in vivo. Observations concerning anterior lens epithelia elongating to a great extent in vitro demonstrate that their cells progressively elongate for only about three days. Well differentiated explants cultured for longer periods do not show greater elongation or further cytoplasmic differentiation. Their cells, at the ultrastructural level, resemble differentiating fibre cells in vivo rather than differentiated ones. It is concluded that the anterior lens epithelium has some capacity for differentiation independent of the ocular environment, but that the latter is essential for the expression of its full developmental potential. / Science, Faculty of / Zoology, Department of / Graduate

Diss. (sammanfattning) Stockholm : Karol. inst. / Härtill 7 uppsatser.

Thesis (Ph. D.)--University of Washington, 1997. / Vita. Includes bibliographical references (leaves [78]-85).

Two experiments investigated the effects of pre-receptoral absorption and levels of illumination on colour vision. Simulation filters approximating lens and macular pigment changes were constructed on the basis of previous investigations. Experiment I investigated the effects of these filters on young, normal subject performance. Shifts were found in the direction of ageing populations but not as great as is required. Experiment II investigated the additional effect of reductions in illumination. The two experimental manipulations together account for senile decreases in discrimination at slightly higher levels than previously reported / Arts, Faculty of / Psychology, Department of / Graduate

Diss. (sammanfattning) Stockholm : Karolinska institutet, 2007. / Härtill 4 uppsatser.

Diss. (sammanfattning) Stockholm : Karolinska institutet, 2005. / Härtill 5 uppsatser.

Licentiatavhandling (sammanfattning) Stockholm : Karol. inst., 2005. / Härtill 3 uppsatser.

Diss. (sammanfattning) Umeå : Umeå universitet, 2009. / Härtill 4 uppsatser.