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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.
41

Análise morfométrica digital na parede aórtica de suínos após implante de stents não revestidos versus stents revestidos com dacron / Digital morphometric analysis on the aortic wall of pigs after implants of non coated stents versus coated stents with dacron

Dutra, Clandio de Freitas January 2001 (has links)
Os stents são dispositivos intravasculares implantados com o objetivo de dilatar ou fixar a placa de colesterol contra a parede arterial. O objetivo avaliar dois tipos de stents de aço inoxidável, um recoberto com poliéster (dacron) e outro não recoberto, implantados na aorta infra-renal de suínos jovens, foram avaliados por morfometria digital para medir o espessamento intimal. Foi realizado um estudo experimental randomizado, separados em dois grupos(stents não revestidos e revestidos com dacron) e duas fases (I e II). Oito stents recobertos com dacron e oito stents de aço inoxidável (30mm de extensão e 8 mm de diâmetro), não revestidos, foram implantados através de abordagem retroperitoneal na aorta infrarenal normal de 16 suínos normolipêmicos. Para a passagem do sistema de implante, foi necessário uma pequena arteriotomia na aorta distal (fase I). Após quatro semanas, a aorta com os stents foram removidas em monoblocos (fase II). Os valores de hematimetria e do lipidograma foram coletados nas duas fases e não apresentaram alterações que pudessem influenciar o estudo. Amostras de tecido dos sítios de fixação (proximal e distal) dos stents foram retiradas, confeccionadas lâminas, que foram coradas pelas técnicas de hematoxilina e eosina de Verhoeff e enviadas para análise morfométrica digital. A camada intima distal não apresentou diferença estatística significativa. A camada média proximal das porções proximal e da porção distal não apresentaram diferença entre os grupos. Os dois tipos de stents apresentaram 100% de perviedade, boa biocompatibilidade e boa incorporação a parede aórtica de suínos normolipêmicos. A camada íntima proximal do grupo de stents revestidos com dacron apresentou espessura maior do que os stents não revestidos, mas com significância estatísitica limítrofe. / Stents are intravascular devices implanted with the objective of dilating or fixing the cholesterol plate against the arterial wall. To evaluate, by digital morphometry, the intimal thickening after the placement of two different kinds of stents: polyester covered stainless steel stents (Dacron) and non-covered stents implanted in young pigs’ infrarenal aortas. The stents were made at the Biotransformation Laboratory of Federal University of Rio Grande do Sul. The experiment was performed at the Biotério of University of Caxias do Sul, carried out on two separate groups of pigs. Eight polyester-covered stainless steel stents (Dacron) and eight stainless steel stents (30-mm long, 8-mm diameter) were deployed through extraperitoneal approach in the normal infrarenal aorta of 16 normolipemic pigs. To allow the passage of the delivery system, a small arteriotomy was performed (phase I). After four weeks, the aorta with the stent was removed en bloc. (phase II). The values of the hematimetric and lipid analysis did not show any changes that could influence the study. Tissue samples of the fixing sites (proximal and distal) of the stents were taken. Microscope slices were prepared and submitted to Verhoeff’s hematoxilin and eosin techniques and sent to morphometric analysis.The intima immediately proximal to the device was thicker in the group of covered stents with marginal significance. The distal intimal layer, proximal medial layer of the proximal portion and distal portion did not present statistical difference between the two groups. Patency was 100% in both groups of these normolipemic pigs. After four weeks the intimal layer immediately proximal to the covered stents was ticker when compared to uncovered stents, but this had a borderline significance. The intimal layer distal to covered stents and the media proximal or distal to the devices had similar morphometric features when covered and uncovered stents where compared.
42

Histologia e morfometria do aparelho reprodutor de fêmeas submetidas à ovariosalpingo-histerectomia (Canis familiaris, Linnaeus, 1758) /

Diagone, Karen Vicente. January 2005 (has links)
Resumo: Nesta pesquisa foram realizadas a histologia e morfometria de ovários, ovidutos e úteros de cadelas. Foram utilizados 15 animais distribuídos em grupos (G) de acordo com as idades em anos, G1 (1 até 3), G2 (maiores de 3 até 5) e G3 (maiores de 5 até 7). Após a realização da ovariosalpingo-histerectomia, ovários, fragmentos de tubas uterinas e útero foram fixados e processados rotineiramente para a inclusão em parafina. As amostras foram coradas pela técnica da Hematoxilina-eosina. Os parâmetros morfométricos analisados foram: diâmetros máximo e mínimo (æm), perímetro (æm), área (æmø), fator de forma do citoplasma e núcleo dos oócitos dos diferentes tipos de folículos e espessura das camadas salpíngicas e uterinas. Os procedimentos estatísticos utilizados foram ANOVA e o teste Tukey (5%). Houve diferenças significativas entre os grupos experimentais para os parâmetros do citoplasma e núcleo de oócitos foliculares e para a espessura das camadas salpíngicas e uterinas. Concluiu-se que de acordo com os resultados desta pesquisa a maturação in vitro, obtém melhores desempenhos na utilização de oócitos de folículos primordiais nas fêmeas correspondentes ao G3 e para oócitos inclusos em folículos secundários e terciários, as do G2; as diferenças nas espessuras das camadas uterinas podem ser uma das explicações para o desenvolvimento diferenciado dos fetos em fêmeas caninas; os valores obtidos neste estudo servirão como subsídios para a biotecnologia da reprodução, diagnóstico e prognóstico de enfermidades que acometem esta espécie. / Abstract: The objectives of this work were the histologyc and morphometric study of ovaries, oviducts and uterus of canines females. There were 15 animals distributed in groups involved according to their age, Group 1 (G1), Group 2 (G2) and Group 3 (G3). To the histological analysis after the accomplishment of the ovariehisterectomy, the ovaries, fragments of oviducts and uterus were fixed and processed routinely for inclusion in paraffin. The samples were stained by haematoxilyn-eosin technique. The morphometric parameters studied were: maximum and minimum diameters (æm), perimeter (æm), area (æm2), roundness factor of nucleus and cytoplasm of oocytes of different kinds of follicles and thickness of oviduct and uterine layers. The statistical procedures used were ANOVA and Tukey's test. There was significantly difference in oocytes of follicles: primordials in the cytoplasm for maximum and minimum diameters, perimeter and area between the G1 and G3, unilaminar primary in the cytoplasm for roundness factor between the G1 and G2, secondary in the nucleus for maximum and minimum diameters, perimeter and area between the G1 and G2 and G2 and G3, tertiary in the nucleus for minimum diameter, perimeter and area between the G1 and G2 and G2 and G3. In the oviduct there was significantly difference in: the infundibulum for mucosa between the G2 and G3, and the serose between the G1 and G3, the ampulla for mucosa and serose between the G1 and G2, the isthmus for serose between the G1 and G2 and G1 and G3. In the uterus there was significantly difference in: the segment 1 of myometrium between the G1 and G3 and G2 and G3, the segment 2 of miometrium between the G1 and G2 and G1 and G3. It concludes that this study will serve as subsidy for the biotechnology of the reproduction, the diagnosis and prognostic of diseases that impaired this specie. / Orientador: Wilter Ricardo Russiano Vicente / Coorientador: Maria Rita Pacheco / Banca: Ivo Walter dos Santos / Banca: Marion Burkhardt de Koivisto / Mestre
43

Candidate gene analyses of craniofacial variation in malocclusion phenotypes

Souza Gomes da Fontoura, Clarissa 01 May 2019 (has links)
The precise role that genes play in early craniofacial development and postnatal craniofacial growth are essential to understand dento-facial development overall. However, genotype-phenotype correlations between genetic variation of early craniofacial genes and adult craniofacial phenotypes is poorly understood. Thus, this thesis focused on identifying the genetic etiology underlying phenotypic variations present in malocclusion conditions. First, we performed genotype-phenotype association analyses between common variants in 82 craniofacial genes and phenotypic variations extracted from 2D and 3D pre-treatment dental records of individuals with malocclusion. This effort identified that variant rs2189000 upstream of TWIST1 is highly associated with mandibular body length and inclination and cranial base angulations which can lead to malocclusion. Next, via cell based functional assays, we discovered that rs2189000 disrupts a PITX2 binding site and also showed the direct regulation of TWIST1 expression by the PITX2 gene. Finally, we identified abnormal craniofacial phenotypes and malocclusion in Twist1 deleted mice including asymmetric snouts, domed cranial vaults, and changes in size and inclination of the cranial base, palate and mandible resulting in malocclusion and resembling the human phenotypes observed. Also, premature calcification of calvarial sutures and cranial base synchondroses were also observed in the mutant mice indicating a possible biological mechanism for the abnormal phenotypes detected. These results confirm that TWIST1 is an important regulator of postnatal growth and that genetic variation in TWIST1 can result in malocclusion. The continued identification of genetic etiological factors and their role in craniofacial growth will impact treatment and prevention of malocclusion and other craniofacial conditions
44

Morphometric Analysis of Hippocampal Subfields

Shan Cong (6845576) 17 October 2019 (has links)
Alzheimer's disease (AD) is an irreversible neurodegenerative brain disease distinguished by progressive impairment of memory and decline in cognitive abilities. The hippocampus is widely recognized to play essential roles in forming and gradually transferring information from short-term memory into long-term memory, and it is involved in the onset of the neuropathological pathways of the brain to suffer neuron loss in the rise of AD. Thus, hippocampal information obtained from magnetic resonance imaging (MRI) scans have been established as crucial AD biomarkers. The hippocampus is composed of multiple subfields, and the neuron loss is not uniformly distributed on the whole hippocampus. However, this critical subfield information is not addressed by the existing surface-based morphometry (SBM) and voxel-based morphometry (VBM) studies. Due to the size, complexity, heterogeneity, and folding anatomy of the hippocampus, acquiring volumetric and morphometric measures of hippocampal subfields usually presents not only technical challenges in quantitative neuroimaging but also analytical challenges. To address these challenges and deeply understand the relationships between hippocampal shape changes and brain disorders, especially to examine the degeneration of hippocampal subfields, this thesis focuses on constructing a hippocampal subfield morphometric analysis framework including the following aspects: 1) hippocampal subfield segmentation; 2) 3D shape modeling; 3) feature formulation; 4) diffeomorphic surface registration; 5) surface shape reconstruction; and 6) association analytics. The goals include developing accurate hippocampal subfield guided registration methods, extracting useful features and identifying significant subfields on the hippocampus that are highly related to cognitive disabilities, and using such information to assist early detection of AD.
45

Digital topologic and geometric approaches for CT-based multi-generation characterization of airway and pulmonary vascular tree morphology and their association

Jin, Dakai 01 December 2016 (has links)
Chronic obstructive pulmonary disease (COPD) is a type of obstructive lung disease characterized by chronically poor airflow, which is the result of breakdown of lung tissue (known as emphysema) and small airways disease. It typically worsens over time. Most treatments are limited to the management of symptoms, which makes early detection more valuable to treat the disease etiology itself. With the advancement of computed tomography (CT), it is able to provide high resolution structural and functional imaging to distinguish the lung anatomic structures, as well as characterize their changes over time. Previously, the majority of CT-based measures have focused on quantifying the extent of airway and parenchymal damage. Recent studies suggests that pulmonary vascular dysfunction is an early lesion in COPD and associated with an emphysematous phenotype. Few studies attempted to quantify pulmonary vessel morphology and compared those measures across COPD groups. However, the scope of examined vascular structures in these studies was limited, majorly due to the lack of a standardized method to quantify a broad range of vascular structures. In this thesis, we propose to use anatomically defined airway branches as references to locate and morphologically quantify central pulmonary arteries in different lung regions. Although pulmonary vessel trees have complex topologic and geometric structures, airway tree possesses much simpler and consistent branching patterns and standardized anatomic nomenclatures are available up to sub-segmental levels. It is also well-known that airway and arterial branches have a unique pairing that is established by their spatial proximity and parallel configuration. Therefore, anatomically labeled airway tree provides a robust benchmark to locate consistent arterial segments for both intra- and inter-subjects. New methods have been developed for quantitative assessment of arterial morphology matched and standardized by associated airways at different anatomic branches. First, the skeletons of airway and vessel trees are generated to provide simple and hierarchical representations. Then, topologic and geometric properties of airways and arteries, such as distance, orientation and anatomic positon information, are explored to locate the target arterial segments. Finally, the morphologic properties, e.g. cross-sectional area, of target arterial segments are robustly computed. The developed methods in this thesis provides a standardized framework to assess and compare the vascular measurements in intra- and inter- subjects from a broad range of vessel branches in different lung regions. The work also serves as a practical tool for large longitudinal or cross-sectional studies to explore the pulmonary vessel roles played at the early stage of COPD. The major contribution of this thesis include: (1) developing two novel skeletonization methods that are applicable to airway and pulmonary vessel trees; (2) developing a semi-automatic method to locate and quantify central pulmonary arterial morphology associate to anatomic airway branches; (3) developing a fully automatic method to identify and reconstruct central pulmonary arterial segments associated to anatomic airway branches and quantify their morphology; (4) validating the methods using computerized phantoms, physical phantoms and human subjects; (5) applying the developed methods to two human lung disease studies.
46

Morphometric Evaluation of the Whitefish Complex in Bear Lake, Utah/Idaho

Ward, Alan 01 May 2001 (has links)
Whitefish populations around the world have long been difficult to categorize taxonomically. The whitefish of Bear Lake, Utah/Idaho are no exception. There are three recognized species of Prosopium that are endemic to the lake. Two of these species, Prosopium spilonotus and Prosopium abyssicota, have previously been indistinguishable outside of spawning times. Previous studies have proposed additional taxa within P. spi/onotus to further complicate the identification among these taxa. Morphological characteristics were quantified on wild whitefish from Bear Lake, as well as from progeny reared in the laboratory from the wild adult fish. The purported taxa were separated in the field using the best characteristics presented in previous studies, and the progeny were reared separately in these groups. Otolith aging was also done on the wild adult fish to understand the age structure of the spawning populations. Results from otolith aging and morphological analyses on the laboratoryreared fish indicated that there is only one taxonomic group of P. spilonotus. By using scale counts, it was determined that P. spilonotus and P. abyssicola can be distinguished from each other with considerable reliability.
47

Ecology and Taxonomy of Ateles geoffroyi in Parque Nacional Pico Bonito, Atlántida, Honduras

Hines, Justin, justin.hines@opwall.com January 2005 (has links)
The first study on Ateles geoffroyi in Honduras, this research focused on the population of spider monkeys in Parque Nacional Pico Bonito, Atlántida, Honduras. Subgroup size of spider monkeys in Parque Nacional Pico Bonito ranged from 1-23 (n=55) individuals, with a mean subgroup size of 6.93 ± 4.53 individuals, which was larger than nearly all subgroup sizes reported in Central and South America. Mean subgroup composition consisted of 1.65 ± 1.16 adult males, 2.67 ± 1.69 adult females and 1.75 ± 1.92 juveniles. Sex ratio of adult males to adult females was 1:1.62, which was consistent with most Central and South American Ateles studies in the literature.¶ Of a possible 23 identified food tree species from 15 families, and 7 unidentified tree and vine species, spider monkeys were confirmed to consume fruits, leaves and/or seeds from 8 identified tree species, 1 unidentified tree species, and 1 unidentified vine species. Several of the confirmed genera consumed by Ateles in Parque Nacional Pico Bonito were consistent with other studies conducted in Central and South America, including Dialium, Ficus, and Coccoloba.¶ Combining pelage analysis and discriminant analysis of cranial and dental measurements from 140 skins and 253 adult crania, the taxonomy of the Central American Ateles geoffroyi was revised to recognize the taxa Ateles geoffroyi yucatanensis, A. g. vellerosus, A. g. pan, A. g. geoffroyi, A. g. frontatus, A. g. ornatus, and A. g. grisescens, with the recognition of a potential new taxon from northern Honduras, resulting in a revised distribution of Ateles geoffroyi, based on the pelage and cranial analyses.
48

Molecular Phylogeography and Species Discrimination of Freshwater <em>Cladophora</em> (Cladophorales, Chlorophyta) in North America

Ross, Sara J. January 2006 (has links)
<em>Cladophora</em> is a widespread freshwater filamentous cholorophyte genus and is frequently observed in eutrophic waters where it can produce large nuisance blooms. These blooms can have direct impacts on water intake for power generation, irrigation canals and can be aesthetically unpleasant. Much of the ecological and physiological studies on <em>Cladophora</em> have assumed that the populations of this genus in North America belong to the species <em>Cladophora glomerata</em>. However, this has never been tested despite that it is well documented that identifying freshwater <em>Cladophora</em> to the species level is difficult due morphological variability under different ecological conditions. In addition, the species epithets for freshwater <em>Cladophora</em> are based on European collections and it is not clear if these should be applied to North America. This study examines approximately 40 collections of <em>Cladophora</em> from the Laurentian Great Lakes and 43 from various locations in North America ranging from the Northwest Territories to Puerto Rico. Initially we determined the nucleotide sequences of the internal transcribed spacer (ITS) region of the nuclear ribosomal cistron and observed sequence divergence to be low (0-3%), demonstrating an inability for this marker to resolve species delineation as divergence of this region was low. Amplification of the inter-simple sequence repeat (ISSR) regions were used to analyze microsatellite motif frequency throughout the genome to evaluate the biogeography relationships, including diversity, of freshwater <em>Cladophora</em> sp. five different primers were used on 70 individuals. UPGMA analyses of the presence/absence of bands demonstrate that each of the Great Lake populations separate into groups according to the Lake they were initially sampled from. However, collections from North America are highly variable and do not form well supported biogeographic clades. In addition, these collections appear to be distinct from type cultures of freshwater <em>Cladophora</em> from Europe. Supplementary morphological analysis using suggested taxonomically valid criterion (length and diameter of main axis, ultimate branch, and apical cell) none were able to differentiate Great Lake populations.
49

Molecular Phylogeography and Species Discrimination of Freshwater <em>Cladophora</em> (Cladophorales, Chlorophyta) in North America

Ross, Sara J. January 2006 (has links)
<em>Cladophora</em> is a widespread freshwater filamentous cholorophyte genus and is frequently observed in eutrophic waters where it can produce large nuisance blooms. These blooms can have direct impacts on water intake for power generation, irrigation canals and can be aesthetically unpleasant. Much of the ecological and physiological studies on <em>Cladophora</em> have assumed that the populations of this genus in North America belong to the species <em>Cladophora glomerata</em>. However, this has never been tested despite that it is well documented that identifying freshwater <em>Cladophora</em> to the species level is difficult due morphological variability under different ecological conditions. In addition, the species epithets for freshwater <em>Cladophora</em> are based on European collections and it is not clear if these should be applied to North America. This study examines approximately 40 collections of <em>Cladophora</em> from the Laurentian Great Lakes and 43 from various locations in North America ranging from the Northwest Territories to Puerto Rico. Initially we determined the nucleotide sequences of the internal transcribed spacer (ITS) region of the nuclear ribosomal cistron and observed sequence divergence to be low (0-3%), demonstrating an inability for this marker to resolve species delineation as divergence of this region was low. Amplification of the inter-simple sequence repeat (ISSR) regions were used to analyze microsatellite motif frequency throughout the genome to evaluate the biogeography relationships, including diversity, of freshwater <em>Cladophora</em> sp. five different primers were used on 70 individuals. UPGMA analyses of the presence/absence of bands demonstrate that each of the Great Lake populations separate into groups according to the Lake they were initially sampled from. However, collections from North America are highly variable and do not form well supported biogeographic clades. In addition, these collections appear to be distinct from type cultures of freshwater <em>Cladophora</em> from Europe. Supplementary morphological analysis using suggested taxonomically valid criterion (length and diameter of main axis, ultimate branch, and apical cell) none were able to differentiate Great Lake populations.
50

Identification Of Morphometric Properties Of Basins Located On Western Part Of Nafz

Sarp, Gulcan 01 February 2012 (has links) (PDF)
This study aims to investigate tectonic activity levels and development stages of the tectonic and hydrologic basin areas located on western part of the main trace of the North Anatolian Fault Zone (NAFZ) using quantitative measurement techniques. The basins investigated are Bolu, Yeni&ccedil / aga, D&ouml / rtdivan, &Ccedil / erkes, Ilgaz and Tosya. The methodology includes application of six morphometric indices (Basin Shape, Hypsometric curve and Hypsometric Integral, Sinuosity of Mountain Fronts, Stream Length Gradient Index, Valley width to height ratio, and Asymmetry Factor) to Digital Elevation Model (DEM) of the region generated from 1:25000 scale topographic maps. The analyses indicate that the basins located in the study area have different characteristics of tectonic activity. According to the results of the applied indices relative order of the activity for tectonic basins is, in decreasing order, Bolu, Tosya, Ilgaz, &Ccedil / erkes, Yeni&ccedil / aga and D&ouml / rtdivan. For hydrologic basins, on the other hand, the same order is observed except for a swap in &Ccedil / erkes and Yeni&ccedil / aga basins. Among the basins located to the north of the NAFZ, the activity decreases eastward whereas to the south the fault zone it decreases towards the west.

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