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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.
21

Product tactics in a complex and turbulent environment viewed through a complexity lens

Mason, Roger Bruce January 2012 (has links)
This paper is based on the proposition that the choice of different product tactics is influenced by the nature of the firm’s external environment. It illustrates the type of product activities suggested for a complex and turbulent environment, when viewing the environment through a chaos and complexity theory lens. A qualitative, case method, using depth interviews,investigated the product activities in two companies to identify the product activities adopted in a more successful, versus a less successful, firm in a complex/turbulent environment. The results showed that the more successful company uses some destabilizing product activities but also partially uses stabilizing product activities. These findings are of benefit to marketers as they emphasize a new way to consider future product activities in their firms. Since businesses and markets are complex adaptive systems, using complexity theory to understand how to cope in complex, turbulent environments is necessary, but has not been widely researched, with even less emphasis on individual components of the marketing mix.
22

Mass spectrometry of lens fiber membrane proteins

Shearer, David B. 03 April 2012 (has links)
Gap junctions are communicating junctions between cells that allow small molecules to pass from the cytoplasm of one cell to the cytoplasm of an adjacent cell. The pores of gap junctions are comprised of two adjacent connexons on neighboring cells, and each connexon is comprised of six connexin proteins. The eye lens of vertebrates is an avascular tissue that is dependent on gap junctions for the distribution of nutrients as well as the removal of waste products. In addition, as the lens cells develop into fibers, they lose their intracellular organelles including the membrane-bound organelles, and are highly dependent on connexons for movement of metabolites and waste materials. Only two connexins, in Bos Taurus Cx44 and Cx49, are highly expressed in lens fiber cells. Thus, the lens offers an excellent system for studying gap junctions. In this study, high-pressure liquid chromatography (HPLC) and mass spectrometry (MS) techniques were used to isolate and characterize connexin proteins from the eye lens of the cow and mouse. Despite over 300 proteins being identified from bovine lens using MS techniques, it was still possible to identify the two connexin proteins following proteolytic digests and MS analysis of the resultant peptides. Several post- translational modifications (PTMs) were identified and characterized in lens fiber connexins, including phosphorylations, acetylations and deamidations and proteolytic cleavages. Changes in phosphorylation of several other lens proteins upon the activation of protein kinase C were also identified. Detection of the orthologous proteins in mouse lens proved more challenging, but peptides derived from both connexin proteins were also detected from this tissue and PTMs of mouse connexins were also observed. Glutathione-S-transferase fusions to mouse Cx44 and Cx50 were used to identify a number of proteins that may interact with the mouse connexins, and the relevance of those interactions was considered. The utility of mass spectrometry to the identification of specific proteins from complex mixtures was clearly demonstrated, and its application to understanding the functional relevance of PTMs was discussed.
23

New solution for well test analysis in reservoirs with permeability discontinuities

Sagawa, Atsushi January 2000 (has links)
No description available.
24

Mass spectrometry of lens fiber membrane proteins

Shearer, David B. 03 April 2012 (has links)
Gap junctions are communicating junctions between cells that allow small molecules to pass from the cytoplasm of one cell to the cytoplasm of an adjacent cell. The pores of gap junctions are comprised of two adjacent connexons on neighboring cells, and each connexon is comprised of six connexin proteins. The eye lens of vertebrates is an avascular tissue that is dependent on gap junctions for the distribution of nutrients as well as the removal of waste products. In addition, as the lens cells develop into fibers, they lose their intracellular organelles including the membrane-bound organelles, and are highly dependent on connexons for movement of metabolites and waste materials. Only two connexins, in Bos Taurus Cx44 and Cx49, are highly expressed in lens fiber cells. Thus, the lens offers an excellent system for studying gap junctions. In this study, high-pressure liquid chromatography (HPLC) and mass spectrometry (MS) techniques were used to isolate and characterize connexin proteins from the eye lens of the cow and mouse. Despite over 300 proteins being identified from bovine lens using MS techniques, it was still possible to identify the two connexin proteins following proteolytic digests and MS analysis of the resultant peptides. Several post- translational modifications (PTMs) were identified and characterized in lens fiber connexins, including phosphorylations, acetylations and deamidations and proteolytic cleavages. Changes in phosphorylation of several other lens proteins upon the activation of protein kinase C were also identified. Detection of the orthologous proteins in mouse lens proved more challenging, but peptides derived from both connexin proteins were also detected from this tissue and PTMs of mouse connexins were also observed. Glutathione-S-transferase fusions to mouse Cx44 and Cx50 were used to identify a number of proteins that may interact with the mouse connexins, and the relevance of those interactions was considered. The utility of mass spectrometry to the identification of specific proteins from complex mixtures was clearly demonstrated, and its application to understanding the functional relevance of PTMs was discussed.
25

Inductive tissue interaction in the development of the mouse lens in vitro

Muthukkaruppan, Veerappan, January 1965 (has links)
Thesis (Ph. D.)--University of Wisconsin--Madison, 1965. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.
26

Expression of the Ets family in the lens

O'Leary, Christine Marie. January 2005 (has links)
Thesis (M.S.)--University of Delaware, 2005. / Principal faculty advisor: Melinda K. Duncan, Dept. of Biological Sciences. Includes bibliographical references.
27

Isospectral orbifold lens spaces

Shams-Ul-Bari, Naveed January 2016 (has links)
Spectral theory is the study of Mark Kac's famous question [K], "can one hear the shape of a drum?" That is, can we determine the geometrical or topological properties of a manifold by using its Laplace Spectrum? In recent years, the problem has been extended to include the study of Riemannian orbifolds within the same context. In this thesis, on the one hand, we answer Kac's question in the negative for orbifolds that are spherical space forms of dimension higher than eight. On the other hand, for the three-dimensional and four-dimensional cases, we answer Kac's question in the affirmative for orbifold lens spaces, which are spherical space forms with cyclic fundamental groups. We also show that the isotropy types and the topology of the singularities of Riemannian orbifolds are not determined by the Laplace spectrum. This is done in a joint work with E. Stanhope and D. Webb by using P. Berard's generalization of T. Sunada's theorem to obtain isospectral orbifolds. Finally, we construct a technique to get examples of orbifold lens spaces that are not isospectral, but have the same asymptotic expansion of the heat kernel. There are several examples of such pairs in the manifold setting, but to the author's knowledge, the examples developed in this thesis are among the first such examples in the orbifold setting.
28

Reações biocatalíticas usando células íntegras de Lens culinaris (Lentilha). / Reactions using whole cell biocatalytic lens culinaris (lentil)

Ferreira, Daniele Alves January 2012 (has links)
FERREIRA, D. A. Reações biocatalíticas usando células íntegras de Lens culinaris (Lentilha). 2012. 144 f. Tese (Doutorado em Química) - Centro de Ciências, Universidade Federal do Ceará, Fortaleza, 2012. / Submitted by José Jairo Viana de Sousa (jairo@ufc.br) on 2014-10-17T19:36:21Z No. of bitstreams: 1 2012_tese_daferreira.pdf: 4506710 bytes, checksum: 94cfd04a00906636065e44839b576c29 (MD5) / Approved for entry into archive by José Jairo Viana de Sousa(jairo@ufc.br) on 2015-03-10T22:06:31Z (GMT) No. of bitstreams: 1 2012_tese_daferreira.pdf: 4506710 bytes, checksum: 94cfd04a00906636065e44839b576c29 (MD5) / Made available in DSpace on 2015-03-10T22:06:32Z (GMT). No. of bitstreams: 1 2012_tese_daferreira.pdf: 4506710 bytes, checksum: 94cfd04a00906636065e44839b576c29 (MD5) Previous issue date: 2012 / This paper describes the use of seeds of lentil (Lens culinaris) as intact plant system in biocatalytic reactions of reduction and hydrolysis. Initially, some plant sources were evaluated for their action in the biocatalytic reduction of aromatic ketone acetophenone. The plants that showed positive results in the reduction reaction underwent determination of their protein content by the methods of Lowry and Bradford. Lens culinaris was plant species revealed that most relevant biocatalytic activity, in agreement with their high protein content (1.33 mg / mL and 1.07 mg / mL according to Bradford and Lowry methods, respectively), and thus The plant was selected for further study. Subsequently, always using the model substrate acetophenone as the reaction parameters were optimized: concentration of biocatalyst; reaction kinetics; stirring speed the reaction medium. After selecting these parameters, the bioreduction reactions were extended to other derivatives of prochiral acetophenone, which were observed with bioconversions yields and enantiomeric excess (ee) ranging from low to high percentages. Generally, were observed steric and electronic influences due to the type and relative position of the various substituents on aromatic compounds. In the case of substrates containing two different functional groups susceptible to reduction, low chemoselectivity observed. Investigated also other carbonyl compounds such as aliphatic and aromatic ketones, aromatic aldehydes and aromatic nitro compounds. In addition investigated the possibility that hydrolytic action from compounds belonging functions esters, amides and nitriles. The yields of the reactions were calculated using Gas Chromatography coupled with Mass Spectrometry (GC-MS) and Nuclear Magnetic Resonance Hydrogen (1H NMR). The enantiomeric excess (ee) were determined by High Performance Liquid Chromatography (HPLC) equipped with chiral columns. / Este trabalho relata a utilização das sementes de lentilha (Lens culinaris) como sistema íntegro de planta em reações biocatalíticas de redução e hidrólise. Inicialmente, algumas fontes vegetais foram avaliadas quanto sua ação biocatalítica na redução da cetona aromática acetofenona. Os vegetais que revelaram resultados positivos na reação de redução foram submetidos à determinação do seu teor de proteínas através dos métodos de Lowry e Bradford. Lens culinaris foi à espécie vegetal que revelou atividade biocatalítica mais relevante, em acordo com seu alto teor de proteína (1,33 mg/mL e 1,07 mg/mL, segundo os métodos de Bradford e Lowry, respectivamente), e assim, foi o vegetal selecionado para estudos mais aprofundados. Posteriormente, utilizando sempre a acetofenona como substrato modelo foram otimizados os parâmetros reacionais: concentração do biocatalisador; cinética de reação; velocidade de agitação e meio reacional. Após seleção desses parâmetros, as reações de biorredução foram estendidas a outros derivados pró-quirais da acetofenona, onde foram observadas bioconversões com rendimentos e excessos enantioméricos (ee) que variaram de baixas a elevadas porcentagens. De modo geral, foram observadas influencias eletrônica e estérica devidas ao tipo e a posição relativa dos diferentes substituintes nos compostos aromáticos. No caso de substratos contendo dois grupos funcionais diferentes suscetíveis de redução, foi observada baixa quimiosseletividade. Foram investigados também outros compostos carbonilicos, como: cetonas alifáticas e aromáticas, aldeídos aromáticos e nitrocompostos aromáticos. Em adição foi investigado a possibilidade de ação hidrolítica a partir de compostos pertencente às funções ésteres, amidas e nitrilas. Os rendimentos das reações foram calculados utilizando Cromatografia Gasosa acoplada à Espectrometria de Massas (CG-EM) e Ressonância Magnética Nuclear de Hidrogênio (RMN 1H). Os excessos enantioméricos (ee) foram determinados através de Cromatografia Líquido de Alta Eficiência (CLAE) equipada com colunas quirais.
29

Towards the induction of lens regeneration: Lessons learned from newts

Tsissios, Georgios Dimitrios 14 November 2022 (has links)
No description available.
30

Contact Lens Discomfort, Vision Correction Preferences, and Accommodative Treatment in Presbyopic and Non-Presbyopic Contact Lens Wearers

Rueff, Erin M. 18 October 2018 (has links)
No description available.

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