Axolotl uniquely generates blastema cells as a pool of progenitor/stem cells to restore an entire limb, a particular property that other organisms, such as humans, do not have. What underlies these differences? Is the main difference that cells residing at the amputation plane (in the stump) undergo reprogramming processes to re-enter the embryonic program, which allows developmental patterning to start, or are there fundamental differences? There is also a significant debate about whether regeneration occurs via stem cell differentiation or by dedifferentiation of mature limb tissue. The aim of my thesis was to address following questions: Are the cells in the blastema reprogrammed or differentiated to regenerate? Are the blastema cells genetically reactivated de novo during regeneration? How does the amputated limb exactly know which part of the limb needs to be regenerate? Using a novel technique of long-term genetic fate mapping, my team demonstrated that dedifferentiation in regenerated axolotl muscle tissue does not occur. Instead, PAX7+ satellite cells indeed play an important role during muscle regeneration in the axolotl limb. Surprisingly, this is in contrast to the newt, which regenerates muscle cells through a dedifferentiation process. Therefore, there is a fundamental difference that underlies the regenerative mechanism ((Sandoval-Guzman et al., 2014) [KR1]). This demonstrates that there is an unexpected diversity and flexibility of cellular mechanims used during limb regeneration, even among two closely related species. Finally, if one salamander species uses a mammalian regenerative strategy (Cornelison and Wold, 1997; Collins et al., 2005) involving stem cells and another uses a dedifferentiative strategy, this raises the question of whether there are other fundamental aspects of regeneration that could also be anomalous. This hypothesis is promising since there could be more than one possible mechanism to induce mammalian regeneration. The process of limb regeneration in principle seems to be more similar to those of limb development as historically assumed. We showed molecularly that embryonic players are reused during regeneration by reactivating the position- and tissue-specific developmental gene programs by using the newly isolated Twist sequences as early blastema cell markers ((Kragl et al., 2013) [KR2]). To gain insights into the molecular mechanisms of the P/D limb patterning in general, it was crucial to study the early patterning events of the resident progenitor/stem cells by using the specific blastema cell marker HoxA as a positional marker along the proximo-distal axis. Our HOXA protein analysis using high molecular and cellular resolution as well as transplantation assays demonstrated for the first time that axolotl limb blastema cells acquire their positional identity in a proximal to distal sequence. We found a hierarchy of cellular restrictions in positional identities. Amputation at the level of the upper arm showed that the blastema harbors cells, which convert to lower arm and hand. We observed ((Roensch et al., 2013) [KR3]) for the first time that intercalation- the intermediate element (lower arm) arises later from an interaction between the proximal and distal cells identities- does not occur. Intercalation, which has been an accepted model for a long time, is not the patterning mechanism underlying normal (without any manipulation) limb regeneration that is unique to axolotl. We further demonstrated, using the Hox genes as markers that positional identity is cell-type specific since their effects were confirmed to be present in the lateral plate mesoderm- derived cells of the limb. As our knowledge about limb blastemas expands concerning cell composition and molecular events controlling patterning, the similarity to development is becoming more and more clear. My work has resolved many ambiguities surrounding the molecularly identification of different types of blastema cells and how P/D limb patterning occurs during regeneration in comparison to development. It has highlighted the importance of combining high-resolution methods, such as in situ hybridizations, single-cell PCR (sc-PCR) of individual dissociated blastema cells and genetic labeling methods with grafting experiments to map cell fates in vivo. In addition to understanding the processes of regeneration, another long-term goal in the regenerative medicine field is to identify key molecules that trigger the regeneration of tissues. Recently, my colleague Takuji Sugiura (Sugiura et al., 2016) observed that an early event of blastema formation is the secretion of molecules like MLP (MARCKS-like protein), which induces wound-associated cell cycle re-entry. Such findings further increase the enthusiasm of biologists to understand the underlying principles of regeneration. By building our knowledge of the molecules and pathways that are involved in tissue regeneration, we increase the possibility of identifying a way to ‘activate’ regenerative processes in humans and thus reach the final goal of regenerative medicine, which is to use the concepts of cellular reprogramming, stem cell biology and tissue engineering to repair complex body structures.

Au cours de gastrulation chez la Drosophile, deux vagues successives de constriction ont lieux au niveau des cellules ventrales menant à l'invagination du mésoderme. La première vague de constriction est stochastique et entraine la constriction de 40% des cellules mesodermales réparties aléatoirement et est contrôlée par le facteur de transcription Snail. La seconde vague de constriction arrive immédiatement après et implique également la constriction des 60% manquant de cellules mésodermales. Cette seconde vague est contrôlée par le facteur de transcription Twist et requière la présence de la protéine sécrétée Fog. L'invagination complète du mésoderme riquière la redistribution de la protéine moteur Myosine II au niveau de l'apex des cellules en cours de constriction. Il a été montré que la mutation de Snail mène à une perte des deux phases de constriction, mais qu'une indentation sur les cellules du mésoderme permet de rétablir la seconde phase de constriction Twist dépendante. Nous avons cherché à étudier les interaction entre les deux phases de constriction, la protéine sécrétée Fog et le moteur moléculaire Myosine II à l'aide d'une simulation numérique. Nous avons également chercher à étudier la corélation entre l'invagination globale du mésoderme et la phosphorylation de la Bêta-Cathenine qui est impliquée dans l'activation de Twist. Nous avons étudier l'invagination de l'endoderme postérieur qui présente de nombreuses similitude avec l'invagination de l'endoderme et leurs interactions. Enfin également à l'aide d'une simulation numérique, nous avons testé l'hypothèse de l'apparition d'une invagination dans un organisme primitif mécano-sensible ( la gastræ d'HAECKEL ) au contact avec le plancher océanique. / During Drosophila gastrulation, two waves of constriction occur in the apical ventral cells, leading to mesoderm invagination. The first constriction wave is a stochastic process mediated by the constriction of 40% of randomly positioned mesodermal cells and is controlled by the transcription factor Snail.The second constriction wave immediately follows and involves the other 60% of the mesodermal cells. The second wave is controlled by the transcription factor Twist and requires the secreted protein Fog. It is known that Snail mutation lead to the loss of the two constriction phases but a mechanical poking on the mesoderm cells can rescue de second phase of Twist dependent constriction. The interactions between the two constriction phases, la secreted protein Fog and the molecular motor Myosin II with a numerical simulation. The posterior endoderm invagination that presents similarities with mesoderm invagination have been study, as well as the interaction between them. Finally with an other numerical simulation, the hypothesis of an induced invagination on a primitive mechanosensible organism ( the HAECKEL grastrae ) on the contact with the oceanic floor has been tested.

This diploma thesis on the theme Improving quality of GSM Banking services for T-Mobile customers deals with detailed analysis of the selected product, which the T-Mobile company has been mediating to all it´s customers for years. This analysis resides in comparing of GSM Banking services with other mobile operators operating on the contemporary Czech market. My thesis contains general theoretical and concrete practical resources, which offer possibilities of improving and innovation of the present situation.

Axolotl uniquely generates blastema cells as a pool of progenitor/stem cells to restore an entire limb, a particular property that other organisms, such as humans, do not have. What underlies these differences? Is the main difference that cells residing at the amputation plane (in the stump) undergo reprogramming processes to re-enter the embryonic program, which allows developmental patterning to start, or are there fundamental differences? There is also a significant debate about whether regeneration occurs via stem cell differentiation or by dedifferentiation of mature limb tissue. The aim of my thesis was to address following questions: Are the cells in the blastema reprogrammed or differentiated to regenerate? Are the blastema cells genetically reactivated de novo during regeneration? How does the amputated limb exactly know which part of the limb needs to be regenerate? Using a novel technique of long-term genetic fate mapping, my team demonstrated that dedifferentiation in regenerated axolotl muscle tissue does not occur. Instead, PAX7+ satellite cells indeed play an important role during muscle regeneration in the axolotl limb. Surprisingly, this is in contrast to the newt, which regenerates muscle cells through a dedifferentiation process. Therefore, there is a fundamental difference that underlies the regenerative mechanism ((Sandoval-Guzman et al., 2014) [KR1]). This demonstrates that there is an unexpected diversity and flexibility of cellular mechanims used during limb regeneration, even among two closely related species. Finally, if one salamander species uses a mammalian regenerative strategy (Cornelison and Wold, 1997; Collins et al., 2005) involving stem cells and another uses a dedifferentiative strategy, this raises the question of whether there are other fundamental aspects of regeneration that could also be anomalous. This hypothesis is promising since there could be more than one possible mechanism to induce mammalian regeneration. The process of limb regeneration in principle seems to be more similar to those of limb development as historically assumed. We showed molecularly that embryonic players are reused during regeneration by reactivating the position- and tissue-specific developmental gene programs by using the newly isolated Twist sequences as early blastema cell markers ((Kragl et al., 2013) [KR2]). To gain insights into the molecular mechanisms of the P/D limb patterning in general, it was crucial to study the early patterning events of the resident progenitor/stem cells by using the specific blastema cell marker HoxA as a positional marker along the proximo-distal axis. Our HOXA protein analysis using high molecular and cellular resolution as well as transplantation assays demonstrated for the first time that axolotl limb blastema cells acquire their positional identity in a proximal to distal sequence. We found a hierarchy of cellular restrictions in positional identities. Amputation at the level of the upper arm showed that the blastema harbors cells, which convert to lower arm and hand. We observed ((Roensch et al., 2013) [KR3]) for the first time that intercalation- the intermediate element (lower arm) arises later from an interaction between the proximal and distal cells identities- does not occur. Intercalation, which has been an accepted model for a long time, is not the patterning mechanism underlying normal (without any manipulation) limb regeneration that is unique to axolotl. We further demonstrated, using the Hox genes as markers that positional identity is cell-type specific since their effects were confirmed to be present in the lateral plate mesoderm- derived cells of the limb. As our knowledge about limb blastemas expands concerning cell composition and molecular events controlling patterning, the similarity to development is becoming more and more clear. My work has resolved many ambiguities surrounding the molecularly identification of different types of blastema cells and how P/D limb patterning occurs during regeneration in comparison to development. It has highlighted the importance of combining high-resolution methods, such as in situ hybridizations, single-cell PCR (sc-PCR) of individual dissociated blastema cells and genetic labeling methods with grafting experiments to map cell fates in vivo. In addition to understanding the processes of regeneration, another long-term goal in the regenerative medicine field is to identify key molecules that trigger the regeneration of tissues. Recently, my colleague Takuji Sugiura (Sugiura et al., 2016) observed that an early event of blastema formation is the secretion of molecules like MLP (MARCKS-like protein), which induces wound-associated cell cycle re-entry. Such findings further increase the enthusiasm of biologists to understand the underlying principles of regeneration. By building our knowledge of the molecules and pathways that are involved in tissue regeneration, we increase the possibility of identifying a way to ‘activate’ regenerative processes in humans and thus reach the final goal of regenerative medicine, which is to use the concepts of cellular reprogramming, stem cell biology and tissue engineering to repair complex body structures.

Call number: LD2668 .T4 1958 H86 / Master of Science

A aplicação de materiais cerâmicos na indústria têxtil, em especial nos processos de produção e modificação de fios é amplamente difundida no mundo. O fator chave para definição da necessidade do uso de um material cerâmico é a abrasividade dos fios associada à velocidade de processamento desse material. Nesse estudo foi focado o processo de texturização por falsa torção, e foi proposto analisar e compreender o impacto da variação de rugosidade de discos de cerâmica (que já tenham sofrido desgaste durante o processamento), sobre as características físicas de um fio de poliamida. Para isso efetuou-se a seleção de discos de cerâmica com diferentes faixas de rugosidade, fixou-se todas demais variáveis da máquina de texturização, e foram produzidos fios em cada uma das faixas. Depois de produzidos, os fios foram submetidos a testes físicos laboratoriais, e os resultados analisados pelo método ANOVA. Foi observado que a variação na rugosidade dos discos afetou principalmente as características de volume do fio (EKB%), não afetando significativamente o alongamento e tenacidade. / Use of ceramic materials in the textile industry, particularly in production and converting processes of yarns is widespread in the world. The key factor which defining the use of a ceramic material is the abrasiveness of the yarns associated by processing speed of the material. This study focused the false twist texturing, and has been proposed to analyze and understand the impact of variation in roughness of ceramic discs (which have already undergone wear during processing) on the physical characteristics of a polyamide yarn. So, the ceramic discs have been selected with different ranges of surface roughness, settled all other variables of the texturing machine, and each yarn were produced in each of the ranges. Once produced, the yarns were subjected to physical testing laboratory, and the results were analyzed by ANOVA. This study indicated that the variation in roughness of the disks mainly affected the characteristics of the yarn crimp (EKB%) not significantly affecting the elongation and tenacity.

No description available.

Quantification of cardiac left ventricular (LV) motion from medical images provides a non-invasive method for diagnosing cardiovascular disease (CVD). The proposed study continues our group\'s line of research in quantification of LV motion by applying optical flow (OF) techniques to quantify LV motion in gated Rubidium Chloride-82Rb (82Rb) and Fluorodeoxyglucose-18F (FDG) PET image sequences. The following challenges arise from this work: (i) the motion vector field (MVF) should be made as accurate as possible to maximise sensitivity and specificity; (ii) the MVF is large and composed of 3D vectors in 3D space, making visual extraction of information for medical diagnosis dffcult by human observers. Approaches to improve the accuracy of motion quantification were developed. While the volume of interest is the region of the MVF corresponding to the LV myocardium, non-zero values of motion exist outside this volume due to artefacts in the motion detection method or from neighbouring structures, such as the right ventricle. Improvements in accuracy can be obtained by segmenting the LV and setting the MVF to zero outside the LV. The LV myocardium was automatically segmented in short-axis slices using the Hough circle transform to provide an initialisation to the distance regularised level set evolution algorithm. Our segmentation method attained Dice similarity measure of 93.43% when tested over 395 FDG slices, compared with manual segmentation. Strategies for improving OF performance at motion boundaries were investigated using spatially varying averaging filters, applied to synthetic image sequences. Results showed improvements in motion quantification accuracy using these methods. Kinetic Energy Index (KEf), an indicator of cardiac motility, was used to assess 63 individuals with normal and altered/low cardiac function from a 82Rb PET image database. Sensitivity and specificity tests were performed to evaluate the potential of KEf as a classifier of cardiac function, using LV ejection fraction as gold standard. A receiver operating characteristics curve was constructed, which provided an area under the curve of 0.906. Analysis of LV motion can be simplified by visualisation of directional motion field components, namely radial, rotational (or circumferential) and linear, obtained through automated decomposition. The Discrete Helmholtz Hodge Decomposition (DHHD) was used to generate these components in an automated manner, with a validation performed using synthetic cardiac motion fields from the Extended Cardiac Torso phantom. Finally, the DHHD was applied to OF fields from gated FDG images, allowing an analysis of directional components from an individual with normal cardiac function and a patient with low function and a pacemaker fitted. Motion field quantification from PET images allows the development of new indicators to diagnose CVDs. The ability of these motility indicators depends on the accuracy of the quantification of movement, which in turn can be determined by characteristics of the input images, such as noise. Motion analysis provides a promising and unprecedented approach to the diagnosis of CVDs. / A quantificação do movimento cardíaco do ventrículo esquerdo (VE) a partir de imagens médicas fornece um método não invasivo para o diagnóstico de doenças cardiovasculares (DCV). O estudo aqui proposto continua na mesma linha de pesquisa do nosso grupo sobre quantificação do movimento do VE por meio de técnicas de fluxo óptico (FO), aplicando estes métodos para quantificar o movimento do VE em sequências de imagens associadas às substâncias de cloreto de rubídio-82Rb (82Rb) e fluorodeoxiglucose-18F (FDG) PET. Com a extração dos campos vetoriais surgiram os seguintes desafios: (i) o campo vetorial de movimento (motion vector field, MVF) deve ser feito da forma mais precisa possível para maximizar a sensibilidade e especificidade; (ii) o MVF é extenso e composto de vetores 3D no espaço 3D, dificultando a análise visual de informações por observadores humanos para o diagnóstico médico. Foram desenvolvidas abordagens para melhorar a precisão da quantificação de movimento, considerando que o volume de interesse seja a região do MVF correspondente ao miocárdio do VE, em que valores de movimento não nulos existem fora deste volume devido aos artefatos do método de detecção de movimento ou de estruturas vizinhas, como o ventrículo direito. As melhorias na precisão foram obtidas segmentando o VE e ajustando os valores de MVF para zero fora do VE. O miocárdio VE foi segmentado automaticamente em fatias de eixo curto usando a Transformada de Hough na detecção de círculos para fornecer uma inicialização ao algoritmo de curvas de nível, um tipo de modelo deformável. A segmentação automática do VE atingiu 93,43% de medida de similaridade Dice, quando foi testado em 395 fatias de eixo menor de FDG, comparado com a segmentação manual. Estratégias para melhorar o desempenho do algoritmo OF nas bordas de movimento foram investigadas usando spatially varying averaging filters, aplicados em seqüências de imagens sintéticas. Os resultados mostraram melhorias na precisão de quantificação de movimento utilizando estes métodos. O Índice de Energia Cinética (KEf), um indicador de motilidade cardíaca, foi utilizado para avaliar 63 sujeitos com função cardíaca normal e alterada / baixa de uma base de dados de imagens PET de 82Rb. Foram realizados testes de sensibilidade e especificidade para avaliar o potencial de KEf para classificar a função cardíaca, utilizando a fração de ejeção do VE como padrão ouro. Foi construída uma curva ROC, que proporcionou uma área sob a curva de 0,906. A análise do movimento do VE pode ser simplificada pela visualização de componentes de campo de movimento direcional, ou seja, radial, rotacional (ou circunferencial) e linear, obtidos por decomposição automatizada. A decomposição discreta de Helmholtz Hodge (DHHD) foi utilizada para gerar estes componentes de forma automatizada, com uma validação utilizando campos de movimento cardíaco sintéticos a partir do conjunto Extended Cardiac Torso Phantom. Finalmente, o método DHHD foi aplicado a campos de FO, criado a partir de imagens FDG, permitindo uma análise de componentes direcionais de um indivíduo com função cardíaca normal e um paciente com baixa função e utilizando um marca-passo. A quantificação do campo de movimento a partir de imagens PET possibilita o desenvolvimento de novos indicadores para diagnosticar DCVs. A capacidade destes indicadores de motilidade depende na precisão da quantificação de movimento que, por sua vez, pode ser determinado por características das imagens de entrada como ruído. A análise de movimento fornece um promissor e sem precedente método para o diagnóstico de DCVs.

Quantification of cardiac left ventricular (LV) motion from medical images provides a non-invasive method for diagnosing cardiovascular disease (CVD). The proposed study continues our group\'s line of research in quantification of LV motion by applying optical flow (OF) techniques to quantify LV motion in gated Rubidium Chloride-82Rb (82Rb) and Fluorodeoxyglucose-18F (FDG) PET image sequences. The following challenges arise from this work: (i) the motion vector field (MVF) should be made as accurate as possible to maximise sensitivity and specificity; (ii) the MVF is large and composed of 3D vectors in 3D space, making visual extraction of information for medical diagnosis dffcult by human observers. Approaches to improve the accuracy of motion quantification were developed. While the volume of interest is the region of the MVF corresponding to the LV myocardium, non-zero values of motion exist outside this volume due to artefacts in the motion detection method or from neighbouring structures, such as the right ventricle. Improvements in accuracy can be obtained by segmenting the LV and setting the MVF to zero outside the LV. The LV myocardium was automatically segmented in short-axis slices using the Hough circle transform to provide an initialisation to the distance regularised level set evolution algorithm. Our segmentation method attained Dice similarity measure of 93.43% when tested over 395 FDG slices, compared with manual segmentation. Strategies for improving OF performance at motion boundaries were investigated using spatially varying averaging filters, applied to synthetic image sequences. Results showed improvements in motion quantification accuracy using these methods. Kinetic Energy Index (KEf), an indicator of cardiac motility, was used to assess 63 individuals with normal and altered/low cardiac function from a 82Rb PET image database. Sensitivity and specificity tests were performed to evaluate the potential of KEf as a classifier of cardiac function, using LV ejection fraction as gold standard. A receiver operating characteristics curve was constructed, which provided an area under the curve of 0.906. Analysis of LV motion can be simplified by visualisation of directional motion field components, namely radial, rotational (or circumferential) and linear, obtained through automated decomposition. The Discrete Helmholtz Hodge Decomposition (DHHD) was used to generate these components in an automated manner, with a validation performed using synthetic cardiac motion fields from the Extended Cardiac Torso phantom. Finally, the DHHD was applied to OF fields from gated FDG images, allowing an analysis of directional components from an individual with normal cardiac function and a patient with low function and a pacemaker fitted. Motion field quantification from PET images allows the development of new indicators to diagnose CVDs. The ability of these motility indicators depends on the accuracy of the quantification of movement, which in turn can be determined by characteristics of the input images, such as noise. Motion analysis provides a promising and unprecedented approach to the diagnosis of CVDs. / A quantificação do movimento cardíaco do ventrículo esquerdo (VE) a partir de imagens médicas fornece um método não invasivo para o diagnóstico de doenças cardiovasculares (DCV). O estudo aqui proposto continua na mesma linha de pesquisa do nosso grupo sobre quantificação do movimento do VE por meio de técnicas de fluxo óptico (FO), aplicando estes métodos para quantificar o movimento do VE em sequências de imagens associadas às substâncias de cloreto de rubídio-82Rb (82Rb) e fluorodeoxiglucose-18F (FDG) PET. Com a extração dos campos vetoriais surgiram os seguintes desafios: (i) o campo vetorial de movimento (motion vector field, MVF) deve ser feito da forma mais precisa possível para maximizar a sensibilidade e especificidade; (ii) o MVF é extenso e composto de vetores 3D no espaço 3D, dificultando a análise visual de informações por observadores humanos para o diagnóstico médico. Foram desenvolvidas abordagens para melhorar a precisão da quantificação de movimento, considerando que o volume de interesse seja a região do MVF correspondente ao miocárdio do VE, em que valores de movimento não nulos existem fora deste volume devido aos artefatos do método de detecção de movimento ou de estruturas vizinhas, como o ventrículo direito. As melhorias na precisão foram obtidas segmentando o VE e ajustando os valores de MVF para zero fora do VE. O miocárdio VE foi segmentado automaticamente em fatias de eixo curto usando a Transformada de Hough na detecção de círculos para fornecer uma inicialização ao algoritmo de curvas de nível, um tipo de modelo deformável. A segmentação automática do VE atingiu 93,43% de medida de similaridade Dice, quando foi testado em 395 fatias de eixo menor de FDG, comparado com a segmentação manual. Estratégias para melhorar o desempenho do algoritmo OF nas bordas de movimento foram investigadas usando spatially varying averaging filters, aplicados em seqüências de imagens sintéticas. Os resultados mostraram melhorias na precisão de quantificação de movimento utilizando estes métodos. O Índice de Energia Cinética (KEf), um indicador de motilidade cardíaca, foi utilizado para avaliar 63 sujeitos com função cardíaca normal e alterada / baixa de uma base de dados de imagens PET de 82Rb. Foram realizados testes de sensibilidade e especificidade para avaliar o potencial de KEf para classificar a função cardíaca, utilizando a fração de ejeção do VE como padrão ouro. Foi construída uma curva ROC, que proporcionou uma área sob a curva de 0,906. A análise do movimento do VE pode ser simplificada pela visualização de componentes de campo de movimento direcional, ou seja, radial, rotacional (ou circunferencial) e linear, obtidos por decomposição automatizada. A decomposição discreta de Helmholtz Hodge (DHHD) foi utilizada para gerar estes componentes de forma automatizada, com uma validação utilizando campos de movimento cardíaco sintéticos a partir do conjunto Extended Cardiac Torso Phantom. Finalmente, o método DHHD foi aplicado a campos de FO, criado a partir de imagens FDG, permitindo uma análise de componentes direcionais de um indivíduo com função cardíaca normal e um paciente com baixa função e utilizando um marca-passo. A quantificação do campo de movimento a partir de imagens PET possibilita o desenvolvimento de novos indicadores para diagnosticar DCVs. A capacidade destes indicadores de motilidade depende na precisão da quantificação de movimento que, por sua vez, pode ser determinado por características das imagens de entrada como ruído. A análise de movimento fornece um promissor e sem precedente método para o diagnóstico de DCVs.

This dissertation explores the ways in which Charles Dickens writes Nancy in Oliver Twist, Anthony Trollope writes Carry Brattle in The Vicar of Bullhampton, and Elizabeth Gaskell writes Esther in Mary Barton to represent and examine some very personal and painful anxiety. About Dickens and Trollope, I contend that they turn their experiences of shame into their prostitute's shame. For Gaskell, I assert that the experience she projects onto her prostitute is that of her own maternal grief in isolation. Further, I argue that these authors self-consciously create biographical parallels between themselves and their prostitutes with an eye to drawing conclusions about the results of their anxieties, both for their prostitutes and, by proxy, for themselves. In Chapter II, I assert that in Nancy, Dickens writes himself and his sense of shame at his degradation and exploitation in Warren's Blacking Factory. This shame resulted in a Dickens divided, split between his successful, public persona and his secret, mortifying shame. Both shame and its divisiveness he represents in a number of ways in Nancy. In Chapter III, I contend that Trollope laces Carry Brattle with some of his own biographical details from his early adult years in London. These parallels signify Carry's personal importance to her author, and reveal her silences and her subordinate role in the text as representative of Trollope's own understanding and fear of shame and its consequences: its silencing and paralyzing nature, and its inescapability. In Chapter IV, I posit that Gaskell identifies herself with Esther, and that through her, Gaskell explores three personal things: her sorrow over the loss of not one but three of her seven children, her possible guilt over these deaths, and her emotional isolation in her marriage as she grieved alone. In her creation of Esther, Gaskell creates a way both to isolate her grief and to forge a close companion to share it, thus enabling her to examine and work through grief. In Chapter V, I examine the preface of each novel and find that these, too, reflect each author's identification with and investment of anxiety in his or her particular prostitute.