Thesis (Ph. D.)--University of Nevada, Reno, 1998. / Includes bibliographical references. Online version available on the World Wide Web.

Thesis (DR. P.H.)--University of Michigan.

Thesis (M.S.)--Worcester Polytechnic Institute. / Keywords: proanthocyanidins; fimbriae; Bacterial adhesion. Includes bibliographical references (leaves 143-145).

Thesis (DR. P.H.)--University of Michigan.

Thesis (Ph. D.)--University of Washington, 1996. / Vita. Includes bibliographical references (leaves [85]-91).

Includes bibliographical references.

Thesis (Ph. D.)--University of Chicago, Committee on Neurobiology, August 1999. / Includes bibliographical references. Also available on the Internet.

Thesis (M.A.)--David Lipscomb College. Graduate Program in Bible Studies, 1985. / Includes bibliographical references (leaves 76-81).

This thesis is a study of the production of human speech sounds by acoustic modelling and signal analysis. It concentrates on sounds that are not produced by voicing (although that may be present), namely plosives, fricatives and aspiration, which all contain noise generated by flow turbulence. It combines the application of advanced speech analysis techniques with acoustic flow-duct modelling of the vocal tract, and draws on dynamic magnetic resonance image (dMRI) data of the pharyngeal and oral cavities, to relate the sounds to physical shapes. Having superimposed vocal-tract outlines on three sagittal dMRI slices of an adult male subject, a simple description of the vocal tract suitable for acoustic modelling was derived through a sequence of transformations. The vocal-tract acoustics program VOAC, which relaxes many of the assumptions of conventional plane-wave models, incorporates the effects of net flow into a one-dimensional model (viz., flow separation, increase of entropy, and changes to resonances), as well as wall vibration and cylindrical wavefronts. It was used for synthesis by computing transfer functions from sound sources specified within the tract to the far field. Being generated by a variety of aero-acoustic mechanisms, unvoiced sounds are somewhat varied in nature. Through analysis that was informed by acoustic modelling, resonance and anti-resonance frequencies of ensemble-averaged plosive spectra were examined for the same subject, and their trajectories observed during release. The anti-resonance frequencies were used to compute the place of occlusion. In vowels and voiced fricatives, voicing obscures the aspiration and frication components. So, a method was devised to separate the voiced and unvoiced parts of a speech signal, the pitch-scaled harmonic filter (PSHF), which was tested extensively on synthetic signals. Based on a harmonic model of voicing, it outputs harmonic and anharmonic signals appropriate for subsequent analysis as time series or as power spectra. By applying the PSHF to sustained voiced fricatives, we found that, not only does voicing modulate the production of frication noise, but that the timing of pulsation cannot be explained by acoustic propagation alone. In addition to classical investigation of voiceless speech sounds, VOAC and the PSHF demonstrated their practical value in helping further to characterise plosion, frication and aspiration noise. For the future, we discuss developing VOAC within an articulatory synthesiser, investigating the observed flow-acoustic mechanism in a dynamic physical model of voiced frication, and applying the PSHF more widely in the field of speech research.

Orientadores: Luiz Sergio Leonardi, Michel Cremer, Luis Alberto Magna / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Ciencias Medicas / Made available in DSpace on 2018-08-10T11:06:50Z (GMT). No. of bitstreams: 1 Trentini_ElianeAnrain_M.pdf: 2064169 bytes, checksum: 0b3a3597ddde6867786067aded166323 (MD5) Previous issue date: 2006 / Resumo: Não há, ainda, um modelo ideal de reconstrução das lesões extensas da via biliar. A reconstrução em Y de Roux é clássica, com vantagens como baixa incidência de refluxo de conteúdo intestinal para as vias biliares. Porém, como não é anatômica, ela dificulta enormemente ou impede o acesso endoscópico à via biliar. Uma técnica fisiológica para a substituição do colédoco é a interposição de segmento pediculado de jejuno entre a via biliar e o duodeno, descrita desde 1950 e realizada com êxito em número expressivo de pacientes. Contudo, esta técnica não se tornou amplamente utilizada. Com o intuito de reconstruir a via biliar de maneira fisiológica foi proposta a aplicação do princípio de Monti às vias biliares, que já está estabelecido em humanos para vias urinárias. Nesta técnica, faz-se a detubularização e retubularização transversa de um segmento de jejuno, promovendo uma modificação no sentido das pregas mucosas, tornando-as longitudinais o que facilita o fluxo de líquidos no seu interior. Ao aplicá-la na reconstrução das vias biliares possibilita-se, sobretudo, o acesso endoscópico, diagnóstico e terapêutico, às vias biliares. No presente estudo, foram operados 13 cães: inicialmente foi realizada ligadura laparoscópica do colédoco dos cães para provocar dilatação da via biliar e icterícia obstrutiva. Após uma semana, foi realizada derivação biliodigestiva por laparotomia com a interposição do tubo jejunal acima descrito entre a via biliar dilatada e o duodeno. Os cães foram submetidos a dosagens bioquímicas de transaminases glutâmico-pirúvica e glutâmico-oxalacética, bilirrubinas totais, fosfatase alcalina e gamaglutamiltransferase no pré-operatório das cirurgias e semanalmente, até a eutanásia, realizada seis semanas após a derivação biliodigestiva, quando foi realizada nova laparotomia e ressecção da peça via biliar-tubo jejunal-duodeno em monobloco para análise macroscópica. Foi coletada bile dos cães por ocasião da derivação biliodigestiva e no sacrifício. Dos 13 submetidos a ligadura laparoscópica de colédoco, um foi excluído porque não alcançou significativa dilatação da via biliar. Após a derivação biliodigestiva três cães morreram; destes três, apenas um apresentou peritonite à necropsia. Portanto, nove cães tiveram seus dados submetidos à análise estatística. Eles apresentaram icterícia obstrutiva após sete dias de ligadura do colédoco, comprovada por exames bioquímicos. Todos os nove animais apresentaram redução gradativa, estatisticamente significativa, de sua colestase após derivação biliodigestiva com a interposição do tubo jejunal pediculado e mantiveram-se saudáveis até o término do experimento. Os valores médios de bilirrubina total, fosfatase alcalina e gamaglutamiltransferase uma semana após ligadura da via biliar foram: 4,39; 3251,7 ; 66,1. Os valores dessas variáveis seis semanas após a derivação biliodigestiva foram 0,11 ; 323,1 ; 10,7, respectivamente. Concluiu-se que o tubo de segmento jejunal interposto entre o colédoco previamente ligado e o duodeno foi eficaz na descompressão da via biliar. A análise macroscópica das peças coletadas mostrou boa integração via biliar-tubo e tubo-duodeno. Com a abertura longitudinal das peças observou-se ótima cicatrização das estruturas anastomosadas e perviedade do tubo jejunal / Abstract: An ideal model for reconstruction of extensive lesions of the biliary tract has not been found so far. The Roux-en-Y reconstruction is a classic reconstruction and presents advantages as the low incidence of intestine contents reflux to the biliary tract. However, since this is not anatomical, it impedes or impairs the endoscopic access to the biliary tract. A physiological technique to replace the common bile duct is the interposition of a pediculated segment of jejunum between the biliary tract and the duodenum, described since 1950 and successfully performed in several patients. However, this technique has not been widely adopted. The present experimental study was proposed for reconstruction of the biliary tract in a physiological manner, by application of the Monti principle to the biliary tract, which is well established in humans for the urinary tract. This technique comprises detubulization and transverse retubulization of a segment of jejunum, changing the mucosal folds in longitudinal direction, thus enhancing the flow of liquids inside it. Its application for reconstruction of the biliary tract would allow endoscopic access to the biliary tract, for both diagnostic and therapeutic purposes. Thirteen dogs were operated in the present study; initially, laparoscopic ligation of the common bile duct of dogs was performed to induce extrahepatic cholestasis. After one week, biliodigestive derivation was performed by laparotomy with interposition of the aforementioned jejunal tube between the dilated biliary tract and the duodenum. The dogs were submitted to biochemical dosage of alanine and aspartate transaminases, total bilirrubin, alkaline phosphatase and gamma-glutamyltransferase preoperatively and weekly for six weeks postoperatively. Another laparotomy was then performed with resection of a monoblock specimen from the biliary tract-jejunal tube-duodenum for macroscopic analysis and the animals were killed. Bile was collected from the dogs upon biliodigestive derivation and upon killing. From the 13 animals submitted to laparoscopic ligation of the common bile duct, one was excluded because significant dilation of the biliary tract was not achieved. Three dogs died after biliodigestive derivation; among these, only one exhibited peritonitis upon autopsy. Thus, data on nine dogs were submitted to statistical analysis. These dogs exhibited obstructive jaundice at seven days after ligation of the common bile duct, as demonstrated by biochemical examinations. All nine animals presented statistically significant gradual reduction of cholestasis after biliodigestive derivation by interposition of a pediculated jejunal tube and were healthy until study completion. The mean values of total bilirubin, alkaline phosphatase and gamma glutamyltransferase at one week after ligation of the biliary tract were: 4.39; 3251.7; and 66.1. The values of these variables at six weeks after biliodigestive derivation were 0.11 ; 323.1 and 10.7, respectively. It was concluded that interposition of a jejunal segment tube between the previously ligated common bile duct and the duodenum was effective for decompression of the biliary tract. Macroscopic analysis of the collected specimens revealed good integration between the biliary tract and the tube and between the tube and the duodenum. Longitudinal sectioning of the specimens revealed optimal healing of the anastomosed structures and patency of the jejunal tube / Mestrado / Cirurgia / Mestre em Cirurgia