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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.
541

Desenvolvimento embrionário e larval de Brycon gouldingi (Teleostei, Characidae) /

Faustino, Francine. January 2010 (has links)
Orientador: Laura Satiko Okada Nakaghi / Banca: Heid Sueli Leme dos Santos / Banca: Elisabeth Romagosa / Resumo: Brycon gouldingi é uma espécie endêmica da Bacia Tocantins-Araguaia e estudos acerca de sua biologia e desenvolvimento ontogenético não se encontram na literatura. Analises morfométrica e morfológica dos períodos embrionário e larval desta espécie contribuirão para o conhecimento de sua biologia e potencial para o cultivo. Para este trabalho, foram capturados exemplares adultos da espécie, provenientes do Rio das Mortes - MT, principal afluente do Rio Araguaia e adaptados em cultivo por cerca de sete meses. Dez coletas foram realizadas na Piscicultura Buriti, Nova Mutum - MT, nos meses de dezembro de 2007 e janeiro de 2008, apos a reprodução induzida dos exemplares, sendo feitas amostragens nos seguintes tempos: extrusão, fertilização (tempo zero), 10, 20 e 30 segundos, 1 min, 1 min e 30s, a cada minuto ate completar 10min, a cada 5min ate atingir 30min, aos 45min, de hora em hora ate completar 24 horas, a cada 2 horas ate completar 48 horas e a cada 3 horas ate a absorção total do vitelo. Ovócitos, ovos, embriões e larvas foram observados em estereomicroscópio, microscopia eletrônica de varredura e microscopia de luz. Foi realizada também a morfometria dos ovócitos liberados por cada fêmea e das larvas desde o momento da eclosão ate a absorção total do vitelo, registrando-se valores de comprimento total da larva, altura e comprimento do saco vitelínico. A temperatura media da água nas incubadoras foi de 26,4±1,12 °C. 0 diâmetro dos ovócitos foi de 1,13±0,06 mm e 54% deles possuíam entre 1,11 e 1,20 mm. 0 período embrionário teve uma duração media de 13,9±0,06 horas pós-fertilização (hpf) sendo dividido em sete fases (zigoto,'1. clivagem, mórula, blástula, gástrula, histogênese/organogênese... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Brycon gouldingi is an endemic species of Tocantins-Araguaia basin and studies about its biology and ontogenetic development are not available in the literature. Morphometric and morphological analyses of embryonic and larval stages of this species will increase the knowledge about its biology and aquaculture potential. To perform this work, adult specimens from Mortes River- MT, the main tributary of Araguaia River were collected and adapted to captivity for seven months. Ten collections were carried out at Buriti Fishculture, Nova Mutum - MT, between December 2007 and January 2008, after induced spawning, comprising samplings in the following periods: extrusion, fertilization (time zero), 10, 20 and 30 seconds, lmin, lmin e 30s, at each minute up to 10min, each 5min up to 30min, at 45min, each hour up to 24 hours, each 2 hours up to 48 hours and each 3 hours up to total yolk absorption. Oocytes, eggs, embryos and larvae were observed under stereomicroscope, scanning electron microscope and light microscope. Morphometry analyses were also performed in the oocytes released by each female and in the oocytes up to total yolk absorption taking into account total larval length, yolk sac height and length values. The mean water temperature in the incubators was 26.4±1.12 °C. The oocyte diameter was equal to 1.13±0.06 mm and 54% of them were between 1.11 and 1.20 mm. The mean duration of the embryonic period was 13.9±0.06 hours post-fertilization (hpf) being divided into seven stages (zygote, cleavage, blastula, gastrula, histogenesis/organogenesis and hatching). At hatching, the total larval length was equal to 3.40±0.07 mm and the yolk sac volume was 0.46±0.081.iL. During the larval development, the appearance of adhesive organs on the cephalic dorsal region plus heart... (Complete abstract click electronic access below) / Mestre
542

Morphological properties of articular chondrocytes in various experimental and clinical conditions

Karim, Asima January 2015 (has links)
Previous work has suggested that there exists a relationship between chondrocyte morphology and matrix metabolism. Changes to chondrocyte morphology have been reported in human cartilage however it is unclear if these are involved in the degenerative process associated with osteoarthritis (OA). In this work, the morphology of human and bovine chondrocytes has been characterised under a range of conditions. Bovine chondrocytes have been utilised in these experiments as bovine cartilage is non-degenerate and the chondrocytes have ‘normal’ morphology. However, if human cartilage have been used instead then there is possibility of having chondrocytes of mixed shapes i.e. both ‘normal’ and ‘abnormal’ cells. The thesis aimed at experimentally inducing morphological changes to chondrocytes to determine whether these changes resemble those observed in human cartilage. The ultimate aim is to model these changes to clarify the link between morphology and matrix metabolism by determining how morphological changes influence matrix metabolism. A classification system was developed for chondrocyte morphology allowing the quantification of chondrocyte shapes under different conditions permitting statistical comparisons. The different conditions utilised were (1) non-degenerate and mildly-degenerate human articular cartilage and (2) two in vitro models (a) weak 3D agarose gels to study the effect of gel strength and increasing concentrations of foetal calf serum (FCS) on morphology of bovine chondrocytes and (b) scalpel induced mechanically-injured bovine cartilage model to study in situ chondrocyte viability and morphology at the injured site in various culture conditions. Additionally, the effect of raised medium osmolarity on the response of chondrocytes to injury was studied to determine if the abnormal morphology could be reversed. Using fluorescence-mode confocal laser scanning microscopy (CLSM), chondrocyte viability, volume and morphology were determined and quantified by using VolocityTM 3D image analysis software. Histological evaluation of matrix by using Haematoxylin and eosin, Alcian blue and Masson’s trichrome staining of matrix produced by chondrocytes cultured in strong or weak agarose gels and in injured cartilage was determined. Additionally, immunohistochemical evaluation of matrix (collagen Types I & II) produced by chondrocytes was also performed. Results demonstrated that in non-degenerate human femoral head cartilage, ~83% chondrocytes were normal in morphology and 17±2% chondrocytes had cytoplasmic processes as compared to mildly-degenerate cartilage where 35±5% abnormal chondrocytes with cytoplasmic processes were present. In non-degenerate cartilage, 11±3% chondrocytes formed small sized clusters however clustering was quite evident in the superficial zone of mildly-degenerate human femoral head cartilage where 43±16% chondrocytes had formed large clusters. In mildly-degenerate cartilage the number of abnormal chondrocytes with processes, length of processes and number of processes per cell were greater in the superficial as compared to mid and deep zones. A model was developed to study the effect of external supporting agarose gel on chondrocyte morphology and also to determine the influence of FCS. Bovine chondrocytes cultured in weak gels after 7 days developed similar morphological changes as those observed in degenerate human cartilage. However, in the strong gels only few chondrocytes with morphological changes were present i.e. similar to non-degenerate cartilage. These morphological changes (development of clusters and processes) occurred more rapidly with increasing concentrations of FCS. Histology revealed less Alcian blue staining intensity around chondrocytes cultured in weak gels as compared to strong gels suggesting altered matrix produced by abnormal chondrocytes. FCS and gel strength were therefore proposed as related factors in regulating chondrocyte morphology. In the bovine injured cartilage explant model, after 14 days chondrocytes at the injury in the presence of FCS or synovial fluid (SF) produced morphological changes. These changes comprised cell enlargement, flattening, elongation and production of cytoplasmic processes. In the absence of FCS or SF, chondrocytes at the injury remained unaffected and were morphologically ‘normal’. Throughout the cartilage and even in the absence of subchondral bone, chondrocytes displayed morphological abnormalities in the presence of FCS or SF. These findings suggested that this is not the property of chondrocytes in the superficial layers alone rather it is due to the extent of penetration of the ‘factors’ into the matrix and there is no possibility of interference of injured site with osteocytes or bone factors. Histology revealed that these abnormal chondrocytes showed less staining with Alcian blue at the injury suggesting that these morphological changes might play a role in the changes to matrix metabolism. By raising the osmolarity of the culture medium these changes were inhibited and chondrocytes maintained their normal morphology. The results suggest that morphogenic/proliferative factors in FCS or SF and strength/damage to the matrix may be inter-related and act as potent controllers of chondrocyte morphology. Raised osmolarity was found to inhibit the morphological changes suggesting the possibly that hyperosmolarity can antagonise the effects of these factors. The key conclusions from the thesis were (a) in non-degenerate human femoral cartilage a large percentage of chondrocytes ~83% were normal in morphology and the rest were abnormal however in mildly-degenerate cartilage 35±5% abnormal chondrocytes with processes were present (b) the changes to chondrocyte morphology (development of clusters and processes) were exacerbated with cartilage degeneration (c) chondrocytes cultured in the weak gels produced morphological changes as compared to strong gels (d) chondrocytes at the injury displayed marked morphological changes in the presence of FCS or SF (e) by raising the medium osmolarity these morphological changes to chondrocytes at the injury were inhibited. These results show that chondrocyte morphology is complex and strongly dependent on the environmental settings. Experimental conditions were therefore identified which showed increased chondrocyte volume, abnormal morphology with cytoplasmic processes, enhanced proliferation/cluster formation and matrix changes. These changes to volume and morphology of chondrocytes in the models studied in this work had certain similarities to the changes observed in human cartilage suggesting that these shape changes may play a role in the changes to matrix metabolism occurring in OA. These findings may be of translational relevance in clinical and experimental research into cartilage injury and degeneration by providing new insights in understanding the role played by chondrocyte morphology in cartilage degeneration and injury.
543

Molecular genetic and phenotypic analysis of a new C. elegans MAB mutant, mab-29

Canas Simoes, Mariana January 2007 (has links)
No description available.
544

Obstetrical implications of sexual dimorphism in hominoid os coxae

Costa, Stephanie 08 April 2016 (has links)
Many studies have examined pelvic sexual dimorphism and its functional implications in linear analyses, but few have used three-dimensional (3D) methods, which are ideal for complex structures such as the pelvis. This study examines human and ape os coxae using 3D geometric morphometrics (GM) to determine if patterns of sexual dimorphism relate to obstetrical and/or biomechanical requirements. Twenty-five 3D landmarks were collected on 35 human and 116 hominoid os coxae. Generalized Procrustes and principal component analyses were performed on combined and sex-specific species samples. Tests of male and female human os coxae demonstrate dimorphism in several pelvic traits related to increasing birth canal dimensions in females; females have a wider subpubic angle and greater sciatic notch than males, as well as a short ischial spine. Hominoids, however, did not exhibit sexual dimorphism in pelvic shape. These results confirm previous studies showing that human pelvic shape dimorphism is related to the obstetrical requirements of birthing a large fetus, rather than sexual dimorphism in locomotor biomechanics. Future 3D GM research on other primate species that have large neonates relative to maternal size may determine whether the primate pelvis exhibits similar patterns of response to obstetrical selection pressures as in humans.
545

Long-term cocaine use and its potential effect on bone morphology

Appel, Nicollette Selene 01 November 2017 (has links)
There is a vast amount of information that the bones can offer and this can be on a macroscopic level, a microscopic level, or both. Understanding the changes in bone morphology can provide an understanding the broader picture of an individual’s life. The natural progression of changes in bone follows the natural progression of life. On the macroscopic level, morphological changes occur to skeletal elements such as the pubic symphysis and the sternal rib ends. These characteristics are used when determining the age of an individual. On the microscopic level, histological methods have been developed to determine the age of an individual based on changes in the microstructure of an element. While age at death estimations are based on a known sequence of change over time, time is not the only variable that effects bone morphology. Different pathologies and trauma can also alter skeletal elements. Just as disease processes and trauma act of signaling pathways in the body that cause changes in bone to occur, drug use also acts on the brain and can affect the same signaling pathways that are involved in bone regulation. It is hypothesized here that chronic cocaine use will have a detectable effect on bone morphology. The study sample used consisted of rats, some exposed to cocaine and others not. The experimental groups consisted of eleven Male Wistar Rats (Rattus norvegicus) from the Laboratory of Behavioral Neuroscience at Boston University in Boston, Massachusetts. The rat’s self-administered cocaine at a 0.3 mg/kg dosage and the concentration of the IV solution was 1.6 mg/ml of cocaine. The control group includes five female Sprague Dawley rats (Rattus norvegicus) from the Boston University Animal Science Center in Boston, Massachusetts. These rats were exposed to a training protocol but were not given any drugs prior. All samples went through a dissection and maceration process to obtain the femora and humeri. Mass, volume, and length measurements were taken for each element to be used for later analysis. One femur was chosen at random from each rodent to be used for histological analysis. Femora were embedded in a 2-part epoxy resin and then cut in half using a diamond band saw. A Buehler IsoMet Low Speed Saw was used to obtain thinner sections and a Buehler MetaServ 250 grinder was used to achieve a thickness of 100-120 μm. India ink was used for staining and all stained sections were put onto slides, covered with Permount and a cover slip, and labeled. Upon microscopic examination, it was determined that the outer circumferential lamellar bone thickness would be measured and compared between the experimental and control groups. Photographs were taken of each cross-section at 1x and 4x magnification through the NIS-element software. The ImageJ image-processing program was used for analysis. The thickness of the outer circumferential lamellar bone and the thickness of the total cross-section was taken at four random locations of each 4x magnification photograph. The ratio of the thicknesses and the outer circumferential lamellar bone thickness alone were compared. When comparing density values calculated from the original mass and volume measurements, a significant difference was found between the control and experimental groups. Samples that had been exposed to cocaine had lower density values than those not exposed to any drugs. The control group mean density equaled 1.492 g/mL and the experimental group mean density equaled 1.082 g/mL. A significant difference was found between the ratio of the thicknesses and between the outer circumferential lamellar bone thickness alone. The experimental group had ratio values significantly higher than the control group. The control groups mean ratio equaled 0.2686 while the experimental groups mean ratio equaled 0.4427. This indicates that in the control group, the outer circumferential lamellar bone thickness, on average, covered about 25% of the total cross-section, and the experimental groups outer circumferential lamellar bone thickness, on average, covered almost 50% of the total cross-section. These results were similar when comparing the outer circumferential lamellar bone thickness alone. The control groups thickness was significantly lower than the experimental groups thickness. The control group’s thickness measurements had a mean of 189.7674 μm and he experimental group’s thickness measurements had a mean of 343.2753 μm. These results are just the preliminary data that shows that chronic cocaine use does have an effect on bone morphology on a microscopic level. Only on histological characteristic was analyzed but there are many more traits that can be analyzed.
546

Prognosis of resected, early-stage, lung adenocarcinoma patients

Walsh, Kathryn Jane January 2018 (has links)
Lung cancer is the leading cause of cancer related death worldwide; despite recent treatment developments survival rates remain poor and are closely related to the patient’s clinical stage. Even among patients with early-stage lung cancer, which is amenable to surgical resection, prognosis is highly variable; some go on to live disease-free for many years whereas others quickly recur. Although post-operative chemotherapy is available it has associated morbidities and it is unclear which patients would benefit; therefore, there is a need for more effective stratification of patients. The adenocarcinoma sub-type of lung cancer is known to be morphologically heterogeneous however the majority of observed growth patterns, assessed by light microscopy, can be characterised into one of five formations: lepidic, papillary, acinar, solid and micropapillary. The morphology of each tumour has been proposed as a marker of prognosis and several studies have published a link between the most prevalent growth pattern and prognosis; suggesting those with predominantly solid or micropapillary tumours to have the least favourable outcomes. Indeed, it is now recommended that the proportion of each growth pattern and the predominant growth pattern should be reported for all resected lung adenocarcinomas; although no differential treatments have been recommended based on this assessment. The aim of this study was to determine whether combining the analysis of clinicopathological; morphological; and candidate protein, molecular genetic and transcriptomic characteristics in a single cohort of 208 early-stage, resected, adenocarcinomas with clinical follow-up could be used to identify a subset of patients at high risk of recurrence. Comprehensive morphological analysis was carried out including the presence, proportion and number of individual growth patterns; the predominant growth pattern as well as features previously associated with tumour grade (the presence of large numbers of mitotic figures, apoptotic bodies, inflammatory cells, prominent nucleoli, pleomorphic tumour cells, dyscohesive tumour cells and large amounts of necrosis and scar tissue within the tumour). In addition, gene expression was assessed using a panel of 31 cell-cycle related genes, EGFR and KRAS mutation status was determined, and EGFR and TTF1 protein expression investigated. In this study the predominant growth pattern defined by histopathology showed no ability to identify a group of patients with a poorer prognosis either in univariable or multivariable analysis. Univariable analysis identified nodal status [hazard ratio of N1 compared to N0 was 2.16 (95% CI 1.48 to 3.16, p< 0.0005)], clinical stage [hazard ratios of stage IIa and IIb compared to stage Ia were 3.15 (95% CI 1.73 to 5.73, p< 0.0005) and 2.22 (95% CI 1.10 to 4.48, p= 0.025) respectively], the presence of a significant amount of the papillary growth pattern [the hazard ratio of those with less than 8.5% papillary pattern was 0.657 (95% CI 0.44 to 0.98, p= 0.035)], and overall tumour grade score (including an assessment of necrosis, mitosis, apoptosis, nucleoli, scar tissue and inflammatory cells) [hazard ratio 1.71 (95% CI 1.14 to 2.56, p= 0.008)] as significantly associated with prognosis. Multivariable analysis using Cox’s proportional hazards model identified clinical stage (p< 0.0005), the presence of a significant amount of the papillary growth pattern (p= 0.048) and the presence of large numbers of mitotic figures (p=0.029) and apoptotic bodies (p= 0.015) as independently associated with disease specific survival; although after correction for type I errors only clinical stage remained significantly associated with prognosis with patients with stage Ia disease having a significantly better outcomes [hazard ratio 0.418 (95% CI 0.20 to 0.86)]. Classification and regression tree analysis (CART) was used to further explore the data and to develop decision trees for the prognostication of early-stage lung adenocarcinoma patients. Receiver operating characteristic analysis based on 5- year survival showed a minimal improvement in the area under the curve between a model utilizing currently available clinicopathologic characteristics only [nodal status and lesion size, (area under the curve 0.704, 95% CI 0.631 to 0.777)] and one including growth pattern characteristics [area under the curve 0.725, 95% CI 0.654 to 0.796]. The greatest improvement in prognostic accuracy was observed when gene expression analysis was included in the analysis [area under the curve 0.749, 95% CI 0.673 to 0.825]; however even this showed very little impact compared to routinely used clinicopathologic variables. This analysis suggests that the recommended characterisation of lung adenocarcinoma histology is not a robust predictor of patient outcomes; even a broader model which also included indicators of tumour grade and molecular characteristics was unable to identify a model sufficiently robust to implement into clinical practice and thereby potentially alter patient treatment. Currently routinely collected clinical characteristics; including nodal status, size and clinical stage; continue to provide the most robust method of prognostication and detailed and time-consuming morphological analysis offers no significant benefit to the patient.
547

A taxonomic revision of the genus Cymbidium Sw. (Orchidaceae)

DuPuy, David J. January 1986 (has links)
No description available.
548

A critical investigation of the semantic and morphological aspects of terminological incompetence (with special reference to the English-speaking student of Physical Science and History in the Cape Education Department high school)

Venter, Malcolm Gordon January 1984 (has links)
From Background to the thesis: It has been said that 'educational failure is language failure'. It can be argued here that there are many other factors which could cause educational failure and that language failure does not necessarily result in lack of academic success. However, it is no doubt true that the schoolchild who does not attain a certain type of language competence will be handicapped as regards academic performance. The underlying reason for this is the fact that our educational system is heavily reliant on language - and espacially the written language - as a medium of learning as opposed to the 'direct learning' experiences advocated by certain educationists today such as Ivan Illich in America and John Holt in Britain. Language is the basis both of learning and of communicating what has been learnt. From the moment the child steps into his first period class in the morning till he leaves the last five hours later the child is involved in what is primarily a verbal experience.
549

New insights in the morphology and phylogeny of heterocytous cyanobacteria from Peru, including the description of new taxa

MENDOZA CARBAJAL, Leonardo Humberto January 2018 (has links)
Morphology and phylogeny for 36 heterocytous cyanobacterial strains are studied. Discussion with morphological, ecological, and phylogenetically related taxa is given for each strain. Potentially new genera and species are found, one of them being proposed as a novel genus.
550

Descrição e análise comparativa de larvas do gênero Physalaemus Fitzinger, 1826 (Amphibia, Anura, Leiuperidae)

Gomes, Joice 03 September 2013 (has links)
Submitted by Johnsson Rodrigo (r.johnsson@gmail.com) on 2013-09-03T03:42:03Z No. of bitstreams: 1 JOICE_GOMES_DEFINITIVA.pdf: 24606703 bytes, checksum: e837e6f8690a3db96b4b09c3c9c9e527 (MD5) / Approved for entry into archive by Alda Lima da Silva(sivalda@ufba.br) on 2013-09-03T17:57:33Z (GMT) No. of bitstreams: 1 JOICE_GOMES_DEFINITIVA.pdf: 24606703 bytes, checksum: e837e6f8690a3db96b4b09c3c9c9e527 (MD5) / Made available in DSpace on 2013-09-03T17:57:33Z (GMT). No. of bitstreams: 1 JOICE_GOMES_DEFINITIVA.pdf: 24606703 bytes, checksum: e837e6f8690a3db96b4b09c3c9c9e527 (MD5) / FAPESB / Na última revisão taxonômica do gênero Physalaemus Fitzinger, 1826, baseada em características morfológicas de espécimes adultos, foi sugerida que as espécies fossem alocadas em sete grupos de espécies (grupo de Physalaemus albifrons, grupo de P. cuvieri, grupo de P. deimaticus, grupo de P. gracilis, grupo de P. henselii, grupo de P. olfersii e grupo de P. signifer). Atualmente o gênero é composto por 45 espécies das quais 27 apresentam suas larvas descritas e para apenas dez são apresentadas descrições da morfologia oral interna. Visando contribuir para a resolução de problemas taxonômicos e sistemáticos, o objetivo principal deste estudo descrever e comparar larvas do gênero Physalaemus utilizando-se de caracteres da morfologia externa, oral externa e oral interna. No primeiro e segundo capítulos, as larvas de P. albifrons e P. angrensis são descritas. No terceiro capítulo, a morfologia oral interna de 11 espécies é estudada, descrita e comparada. No quarto capítulo, uma análise comparativa da morfologia externa, oral externa e oral interna de 20 larvas é feita. A partir da análise de cluster (UPGMA), utilizando como distância o índice de Gower, obteve-se grau de dissimilaridade de 45% entre os girinos amostrados. Os girinos de P. angrensis, P. camacan, P. signifer e P. spiniger formaram um grupo distinto, compartilhando muitos carcateres, corroborando o grupo morfológico proposto (grupo de Physalaemus signifer). Além disso, as larvas de P. crombiei e P. gracilis são muito semelhantes quanto a todos os aspectos morfológicos. Os girinos de P. signifer e P. jordanensis são os mais semelhantes quanto à morfologia externa; por outro lado, em relação à morfologia oral interna, P. signifer é muito semelhante à de P. angrensis, e os girinos de P. jordanensis compartilham poucos caracteres com as espécies. / Salvador

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