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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

Cortical Thickness and Voxel-Based Morphometry of Classic Motor Regions of Interest in Autism Spectrum Disorder

Duffield, Tyler Cole 01 June 2016 (has links)
Prior research has suggested that any cortical volume (CV) abnormalities in Autism Spectrum Disorder (ASD) need to be further explored by examination of the two determinants of CV, that being cortical thickness (CT) and pial surface area (PSA; Murphy, Beecham, Craig, & Ecker, 2011). The current study suggests that the two determinants of CV should be explored even in the presence of null CV findings, if structure-function analyses are significant (i.e., bi-lateral precentral gyrus and neuropsychological motor test) as demonstrated in the current sample (see Duffield et al., 2013). The only significant anatomic finding was reduced CT in the left frontal motor regions (primarily left precentral gyrus), which also corresponded to the only significant relationship between a motor variable (i.e., grooved pegboard test) and motor region-of-interest (ROI) where ASD had a stronger relationship than typically developing controls (TDC; ASD > TDC). Left hemisphere biased CT group differences has been shown to have the highest classification accuracy (i.e., designation of ASD versus TDC) of morphological parameters (Ecker et al., 2010), yet PSA has been shown to have far greater modulation of CV abnormalities. This is particularly true for subthreshold PSA (Ecker et al., 2013). These prior findings are not only consistent with the current motor ROI findings, but also provide an explanatory framework for the functional neuroanatomy of a generally worse left handed performance (i.e., non-dominant hand) for ASD compared to controls in a generally right handed dominant sample (no significant group differences on handedness). The only significant motor ROI finding was in the left hemisphere (i.e., ipsilateral to worse left handed performance), but subthreshold PSA findings in the right precentral were found and likely provide explanatory power of motor performances in the aggregate, despite a lack of significant statistical differences in a specific motor ROI individually.
42

Morphometrical Methodology in Quantification of Biological Tissue Components

Blomgren, Bo January 2004 (has links)
<p><b>Objective:</b></p><p>To develop and validate computer-assisted morphometrical methods, based on stereological theory, in order to facilitate the analysis and quantitative measurements of biological tissue components.</p><p><b>Material and methods:</b></p><p>Biopsy specimens from the vaginal wall or from the vestibulum vaginae of healthy women, or from women suffering from incontinence or vestibulitis were used.</p><p>A number of histochemical methods for light microscopy were used, and modified for the different morphometrical analyses. Electron microscopy was used to reveal collagen fibre diameter.</p><p>Computer-assisted morphometry, based on image analysis and stereology, was employed to analyse the different tissue components in the biopsies. Computer programs for these purposes were developed and validated.</p><p><b>Results:</b></p><p>The results show that computer-assisted morphometry is of great value for quantitative measurements of the following tissue components:</p><p><b>Epithelium:</b> The epithelial structure, instead of just thickness, was measured in an unbiased way.</p><p><b>Collagen:</b> The collagen fibril diameter was determined in electron microscopic specimens, and the collagen content was analysed in light microscopic specimens.</p><p><b>Elastic fibres:</b> The amount of elastic fibres in the connective tissue was measured after visualisation by autofluorescence.</p><p><b>Vasculature:</b> A stereological method using a cycloid grid was implemented in a computer program. Healthy subjects were compared with patients suffering from vestibulitis. The results were identical in the two groups.</p><p><b>Smooth muscle:</b> A stereological method using a point grid was implemented in a computer program. Using the Delesse principle, the fibres were calculated as area fractions. The area fractions were highly variable among the different specimens.</p><p><b>Conclusion:</b></p><p>Morphometry, used correctly, is an important analysis method in histopathological research. It is important that the methods are as simple and user-friendly as possible. The present studies show that this methodology can be applied for most quantitative histological analyses.</p>
43

Morphometrical Methodology in Quantification of Biological Tissue Components

Blomgren, Bo January 2004 (has links)
<b>Objective:</b> To develop and validate computer-assisted morphometrical methods, based on stereological theory, in order to facilitate the analysis and quantitative measurements of biological tissue components. <b>Material and methods:</b> Biopsy specimens from the vaginal wall or from the vestibulum vaginae of healthy women, or from women suffering from incontinence or vestibulitis were used. A number of histochemical methods for light microscopy were used, and modified for the different morphometrical analyses. Electron microscopy was used to reveal collagen fibre diameter. Computer-assisted morphometry, based on image analysis and stereology, was employed to analyse the different tissue components in the biopsies. Computer programs for these purposes were developed and validated. <b>Results:</b> The results show that computer-assisted morphometry is of great value for quantitative measurements of the following tissue components: <b>Epithelium:</b> The epithelial structure, instead of just thickness, was measured in an unbiased way. <b>Collagen:</b> The collagen fibril diameter was determined in electron microscopic specimens, and the collagen content was analysed in light microscopic specimens. <b>Elastic fibres:</b> The amount of elastic fibres in the connective tissue was measured after visualisation by autofluorescence. <b>Vasculature:</b> A stereological method using a cycloid grid was implemented in a computer program. Healthy subjects were compared with patients suffering from vestibulitis. The results were identical in the two groups. <b>Smooth muscle:</b> A stereological method using a point grid was implemented in a computer program. Using the Delesse principle, the fibres were calculated as area fractions. The area fractions were highly variable among the different specimens. <b>Conclusion:</b> Morphometry, used correctly, is an important analysis method in histopathological research. It is important that the methods are as simple and user-friendly as possible. The present studies show that this methodology can be applied for most quantitative histological analyses.
44

Ultrastructural and Morphometrical Studies on the Reticular Framework and Reticular Fibers in the Reticuloendothelial System of Rats

ASAI, JUNPEI, ABU ABED Y. MOHAMMAD 03 1900 (has links)
No description available.
45

The Role of Collagen VI in the Structure and Properties of the Knee Joint

Henz, Susan January 2009 (has links)
<p>Knee pain is a common complaint among older Americans, nearly half of whom have developed or will develop painful osteoarthritis. Osteoarthritis is primarily a disease of articular cartilage, the low-friction, shock-absorbing connective tissue that lines long bones at their articulating surfaces. Within these joint tissues and within arthritis, the minor protein collagen VI plays an uncertain role, although it has been implicated in several muscle and ligament disorders. Determination of the collagen VI role in bone and cartilage of the knee is the focus of this dissertation.</p><p>Within articular cartilage, collagen VI exclusively localizes to and delimits the pericellular matrix (PCM), which differs from the extracellular matrix (ECM) in composition and structure. To interact with the cell, a molecule must first pass through the PCM. Fluorescent dextran diffusivities were quantified in the cartilage PCM using a newly developed model of scanning microphotolysis (SCAMP), a line photobleaching technique. Diffusion was slower in the PCM than in the ECM, although not in early-stage arthritic tissue. These results support the hypothesis that diffusivity is lower in the PCM than in the ECM of healthy articular cartilage, presumably due to differences in proteoglycan content. </p><p>Arthritic degradation is partly mediated by interleukin-1 (IL-1), a catabolic cytokine that affects the mechanical properties of articular cartilage and preferentially binds to cell-surface receptors in the surface zone. Since cells are the cartilage metabolic units, matrix degradation is hypothesized to influence molecular transport in the PCM before the ECM. Cartilage was cultured with or without IL-1, soaked in FITC-ovalbumin, and photobleached using SCAMP to measure diffusivity. Over 7 days of culture, IL-1 doubled the diffusivity in both zones (surface, middle) and matrices (PCM, ECM) of the cartilage. Diffusivity within the PCM was slightly lower than within the ECM. No increase in PCM diffusivity relative to ECM diffusivity was detected within either zone, suggesting that PCM-localized degradation either cannot be distinguished at these time points or cannot be detected by measures of ovalbumin diffusion.</p><p>To determine the effects of collagen VI absence on the morphometry and physical properties of the joint, knees of 2-, 9-, and 15-month-old Col6a1+/+ and Col6a1-/- mice were studied. Bone morphometry was evaluated using micro-computed tomography (microCT). Subchondral bone thickness, joint-capsule thickness, and cartilage degradation were assessed by histology. Cartilage elastic modulus, roughness, and coefficient of friction were measured by atomic force microscopy (AFM). Diffusion through the cartilage ECM was determined by SCAMP. Overall, collagen VI absence had profound effects on the morphometry of the proximal tibia and the overall histological structures of the mouse knee, yet minimal effects on the friction, roughness, elastic modulus, and diffusional properties of the articular cartilage. Musculoskeletal abnormalities at the knee do result from collagen VI absence.</p> / Dissertation
46

Geomorphology and morphometric characteristics of alluvial fans, Guadalupe Mountains National Park and adjacent areas, west Texas and New Mexico

Given, Jeffrey Lyle 30 September 2004 (has links)
This study qualitatively and quantitatively analyzes the geomorphology of alluvial fans in the Guadalupe Mountains Region (GMR) of west Texas and south-central New Mexico. Morphometric data for 31 alluvial fans and drainage basins ha ve been derived. The data set was subdivided into Guadalupe and Brokeoff Mountain fans and was further subdivided on the basis of their location along the two mountain ranges. A conventional morphometric analysis was conducted relating alluvial fan area and slope to drainage basin area in order to understand if and to what extent the alluvial fans of the GMR are dependent on the physical environment, including characteristics and processes of the drainage basin and depositional site. The results of the morphometric analysis indicate that the morphometric relationships that exist between the alluvial fans of the GMR and their contributory drainage basins are comparably to those of alluvial fans of the western United States. Morphologic and morphometric differences between the various groups primarily reflect geographic differences in the physiography and lithology of the contributory drainage basin, tectonics, and the various physical constraints imposed by the GMR.
47

Analyse morphometrischer Messungen an Astrozyten des Hippokampus von Wildtypmäusen im Vergleich zu GFAP-/- - Vimentin-/- - Mäusen

Gumprecht, Annett 04 December 2013 (has links) (PDF)
Die Forschungsergebnisse der letzten Jahre beweisen, dass die Informationsverarbeitung im ZNS auf eine ausgewogene Interaktion zwischen den Neuronen und den Astrozyten im Sinne eines funktionellen Netzwerkes angewiesen ist. Allerdings liegen nur unzureichende Erkenntnisse über den strukturellen Charakter dieser symbiotischen Beziehung vor. Zu den grundlegenden Aufgaben der Astrozyten gehört die Modulation der synaptischen Aktivität von Neuronen, Aufrechterhaltung der extrazellulären Homoöstase, Ausbildung der Blut-Hirn-Schranke, Pufferung der lokalen Kaliumkonzentration und die Synthese von Zytokinen, Wachstumsfaktoren sowie Neurotransmittern. Ein Hauptbestandteil des Zytoskelettes der Astrozyten stellen die Intermediärfilamente (z.B. GFAP, Vimentin) dar. Funktionell dienen sie dem Aufbau von Zell-Zell- Kontakten, der Stabilisierung des Zytoskelettes und der Verankerung der Zellorganellen im Zytoplasma. Charakteristisch für den strukturellen Aufbau der Astrozyten ist das GFAP, welches hauptsächlich in den Zellfortsätzen lokalisiert ist. Aktuelle Forschungen legen nahe, dass es sowohl unter physiologischen Alterungsprozessen als auch im Rahmen von pathologischen Vorgängen im ZNS (beispielsweise chronischer Alkoholabusus, Alexanderkrankheit, Ischämien und Epilepsie) zu einem prozentualen Anstieg der GFAP-Expression kommt, wobei der Einfluss dieser erhöhten GFAP-Synthese auf die Funktionsfähigkeit der Astrozyten noch nicht umfassend geklärt werden konnte. Im Zentrum dieser Dissertation steht deshalb die Fragestellung, haben Alter und Intermediärfilamente (GFAP, Vimentin) Einfluss auf Morphologie und Zellzahl der Astrozyten im Hippokampus einer Maus? Initial erfolgte die Volumenbestimmung der Astrozytendomänen mittels LSM- Aufnahmen im Reflexionsmodus sowie Vermessung nach Bearbeitung der Präparate mit der Silber Imprägnationstechnik. Die Domäne eines Astrozyten stellt das von einem Astrozyten mit Soma und allen Fortsätzen okkupierte Volumen dar. Nach der Auswahl von S100ß als immunhistochemischen Astrozytenmarker wurde die Zellzählung in entsprechenden Hippokampusarealen durchgeführt. Aus den ermittelten Daten wurde rechnerisch der Überlappungsgrad der hippokampalen Astrozytendomänen bestimmt. Von entscheidendem Interesse war dabei die Möglichkeit einer Überschneidung benachbarter Astrozytendomänen. Aus den Messungen resultiert ein ca 1,6 fach grösseres Volumen der Wildtyp-Tiere im Vergleich zu den Doppel-knock-out-Mäusen. Im Gegensatz dazu zeigten die Ergebnisse der Zellzählung sowohl in der Kontrollgruppe als auch in der Gruppe der Versuchstiere eine vergleichbare Astrozytenanzahl pro mm3. Entsprechend lag der Überlappungsfaktor bei den Doppel-Knock-out-Tieren (0,49) unter dem der Wildtyp-Tiere (0,7). Die abschließende Auswertung erbrachte in allen Untersuchungsgruppen einen Überlappungsfaktor < 1. Ausgehend von der essentiellen Bedeutung der Astrozyten für die Funktionsfähigkeit der Nervenzellen käme es z.B. im Rahmen pathologischer Prozesse, welche mit Gliazellschäden einhergehen, bei einem Überlappungsfaktor < 1 zu erheblichen Engpässen in der neuronalen Versorgung, sowie in der Kompensation äußerer Einflüsse. Die Wahrscheinlichkeit irreversibler Schädigung der Nervenzellen steigt.
48

The vagina : morphological, functional and ecological aspects

Sjöberg, Inga January 1991 (has links)
The vagina is one organ of the body which has not been studied exhaustively. Moreover, most of the studies found in the contemporary literature have been performed on women affected by a variety of genital diseases. In the present study the vaginal epithelium was examined with a histological method, morphometry, whereby cyclical changes related to hormonal variation during the menstrual cycle were demonstrated. Determination of the quantity of estrogen receptors in the vaginal epithelium on two occasions during the menstrual cycle revealed a significantly greater number in the follicular than in the luteal phase. The results of these studies indicate the presence of a menstrual variation in the vaginal epithelium comparable to that in the endometrium. Phenoxymethylpenicillin (pcV) was used as a marker substance to study the dynamics of the transport mechanisms into the vagina. PcV was found to accumulate in the vaginal fluid and high concentrations persisted for a long period of time. In hysterectomized women, the appearance of pcV in the vaginal fluid followed the same pattern. Consequently, the substance is transported through the vaginal wall and need not enter with the secretions from the internal genitalia. The greatest concentration of pcV was in the distal portion of the vagina, possibly due to the specific internal circulation of fluid within the vagina. Bacterial vaginosis as an example of an ‘ecological disease’ has been studied with regard to the formation of endotoxin, a constituent of the cell wall of Gram- negative bacteria. Large amounts of endotoxin were found and the clinical implication of this finding has been pointed out. Furthermore, the influence of pcV on the vaginal microbial flora of healthy women has been investigated. A change from a situation with predominance of lactobacilli to the appearance of Gram-negative rods was observed. In one of the women the lactobacilli disappeared completely and were replaced by E. coliand high levels of endotoxin in the vaginal fluid were found. This study demonstrates the complexity of the ecological balance of the vaginal microbial flora and illustrates the difficulty of defining a ‘normal’ vaginal condition. Is there any unquestionable state of ‘normality’ even in a healthy woman free from symptoms of genital disease? / <p>S. 1-22: sammanfattning, s. 25-64: 6 uppsatser</p> / digitalisering@umu
49

Slope failure in the rectilinear zone of hillsides

TAKEDA, Yasuo, 竹田, 泰雄, KATAOKA, Jun, 片岡, 順, IIDA, Osamu, 飯田, 修, TANAKA, Tanafumi, 田中, 隆文 03 1900 (has links) (PDF)
農林水産研究情報センターで作成したPDFファイルを使用している。
50

Cold adaptation in the Antarctic archeaon Methanococcoides burtonii: the role of the hydrophobic proteome and variations in cellular morphology

Burg, Dominic William, Biotechnology & Biomolecular Sciences, Faculty of Science, UNSW January 2009 (has links)
Very little is known about the hydrophobic proteins of psychrophiles and their roles in cold adaptation. In light of this situation, methods were developed to analyse the hydrophobic proteome (HPP) of the model psychrophilic archaeon Methanococcoides burtonii. Central to this analysis was a novel differential solubility fractionation procedure, which resulted in a significant increase in the efficiency of resolving the HPP. Over 50% of the detected proteins were not identified in previous whole cell extract analyses, and these underwent an intensive manual annotation process producing high quality functional assignments. Utilising the functional assignments, biological context analysis of the HPP was performed, revealing novel and often unique biology. The analysis acted as a platform for differential proteomics of the organism???s response to both temperature and substrate using stable isotope labelling. The results of which revealed that low temperature growth was associated with an increase in the abundance of surface and secreted proteins, and translation apparatus. Conversely, growth at a higher temperature was associated with an increase in the abundance of general protein folding machinery and indications of an oxidative stress response, emphasising that the temperature for maximum growth rate is stressful. Through investigation of the response of M. burtonii to substrate it was found that growth on methanol was stressful, and its low energy yield resulted in an increase in the abundance of energy conserving systems. The extracellular polymeric substance (EPS) and morphology of M. burtonii was also investigated with respect to both temperature and substrate, using a number of techniques in microscopy. It was found that the EPS was comprised of proteins, sugars and RNA, and that growth at different temperatures resulted in the production of EPS that displayed significantly different properties on dehydration, thus indicating compositional variation. When cells were grown on methanol they took on highly irregular shapes and had electron transparent inclusions. The observations from the ultrastructural analysis were contemplated with respect to the proteomic findings, revealing novel avenues of research. This study has highlighted the roles of hydrophobic proteins in cold adaptation biology, and the value of comprehensive proteomics for the examination of adaptation in microorganisms

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