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Very Thick (very + thick)
Selected AbstractsThe Trigeminal Vasculature Pathology in Patients With NeuralgiaHEADACHE, Issue 9 2007Slobodan Marinkovi Objective.,To examine the possible pathological changes of the trigeminal vasculature in patients with neuralgia. Background.,Such a study has never been performed before. The alterations of the trigeminal vessels could have important pathophysiological implications in the trigeminal neuralgia pathogenesis. Methods.,The biopsy specimens for the electronmicroscopic (EM) and immunohistochemical examination were taken during a partial rhizotomy in 6 patients with trigeminal neuralgia and in 2 persons with trigeminal neuropathy. In addition, the 32 normal trigeminal nerves were used as the control specimens. Results.,The vascular pathological alterations were noticed in 3 out of 6 neuralgia patients. The EM study revealed signs of apoptosis or degeneration, respectively, of some endothelial and smooth muscle cells in the wall of the trigeminal arterioles. The immune reactions against CD31, CD34, and ,-smooth muscle actin in these cells were weaker than in the control specimens, but stronger against factor VIII. In addition, the arteriolar basement membranes, which were thickened, showed an intense laminin, fibronectin, and collagen IV immunoreactivity. Similarly, some endothelial cells and pericytes of the intratrigeminal capillaries also showed signs of apoptosis or degeneration, respectively. Their basement membrane was very thick and showed an intense immune reaction against laminin, fibronectin, and collagen IV. Conclusion.,The observed pathological changes of the trigeminal vasculature could be the primary factor, while demyelination of the trigeminal nerve fibers could be the secondary process in some patients with neuralgia. [source] Subglacial modulation of the hydrograph from glacierized basinsHYDROLOGICAL PROCESSES, Issue 19 2008Gwenn E. Flowers Abstract The extent of basin glacierization has important implications for the hydrograph in part, because snow, firn and ice impart different delays in water transport through the system. Here, the significance of subglacial drainage morphology in modulating the hydrograph is examined with a one-dimensional physically based model. The conceptual model of subglacial drainage comprises both ,fast' and ,slow' elements, respectively associated with summer and winter drainage regimes. The additional possibility of a permeable glacier substrate is taken into account by allowing water transport in a subglacial aquifer. Forced by prescribed rates of melt-water delivery to the glacier bed, the model predicts glacier discharge by drainage system provenance. The effects of (1) ,hard' versus ,soft' glacier beds, (2) subsurface permeability and groundwater flow, and (3) glacier geometry are then investigated. Hydrograph character, in the form of peak timing and amplitude, symmetry with respect to the forcing, and the amplitude of diurnal fluctuations, is affected by the partitioning of water through the various flow elements. Hard beds and impermeable substrates maximize the discharge routed through the fast-drainage system in the simulations, generally resulting in higher seasonal discharge maxima and stronger diurnal variations in discharge. High hydraulic transmissivities, either at the glacier bed or in underlying strata, hinder the development of the fast-drainage system in the simulations, producing hydrographs of lower amplitude. Glacier geometry has a modest effect, with adverse bed slopes, very thick or very thin ice and short glacier lengths favouring prolonged drainage through the slow system. These results suggest that the morphology and evolution of the subglacial drainage system may play a significant role in determining the character of the hydrograph from glacierized basins. Copyright © 2008 John Wiley & Sons, Ltd. [source] Improving the efficiency of finite element formulations in laminated compositesINTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING, Issue 9 2002Kostas P. Soldatos Abstract This communication extends the principles of an advanced smeared laminate plate theory towards the development of corresponding FE models and codes. The present FE numerical results are compared with those based on exact elasticity solutions, as well as those of corresponding FE models based on three conventional laminate plate theories. These comparisons show that, compared to those conventional FE codes, the proposed FE formulation that uses also a small and fixed number of nodal degrees of freedom improves substantially the accuracy of stress predictions. They also show that the present numerical results are particularly accurate even for very thick laminates. Copyright © 2002 John Wiley & Sons, Ltd. [source] Influence of abutment substrate and ceramic thickness on the colour of heat-pressed ceramic crownsJOURNAL OF ORAL REHABILITATION, Issue 9 2002T. NAKAMURA Summary All-ceramic crowns made of leucite-based heat-pressed ceramics are widely used to restore non-vital teeth in conjunction with various post and core materials. However, as some light passes through the ceramic, the colour of the abutment substrate can negatively affect the final aesthetic appearance of the all-ceramic crown. In this study, we made background specimens simulating gold-alloy cast posts and other simulating porcelain veneered cast posts, overlaid different thickness of heat-pressed ceramic on these background specimens, and measured the shifts in colour. We found that, when the background specimen was a gold alloy, the background colour had an effect on the apparent colour, unless the ceramic was more than 1·6 mm thick. When the background specimen was porcelain veneered, the background colour had no evident effect, even when the ceramic was not very thick. Therefore, when making a restoration using a leucite-based heat-pressed ceramic crown, it is advisable to use tooth-coloured materials such as a porcelain veneered cast post, if you will not be able to make the ceramic more than 1·6 mm thick. [source] Renal corpuscle of the sturgeon kidney: An ultrastructural, chemical dissection, and lectin-binding studyTHE ANATOMICAL RECORD : ADVANCES IN INTEGRATIVE ANATOMY AND EVOLUTIONARY BIOLOGY, Issue 2 2003José L. Ojeda Abstract The sturgeon is an ancient species of fish that thrives in a wide range of ecological environments, from freshwater to seawater. Basic in this process of adaptation is the ability of the kidney to control fluid filtration and urine formation. However, the morphological basis of this process is mostly unknown. The aim of the present study was to use microdissection techniques (scanning electron microscopy (SEM), transmission electron microscopy (TEM), and lectin-binding histochemistry) to examine the structure of the renal corpuscle of the sturgeon Acipenser nacarii in order to reveal morphologic features that could be related to function, phylogeny, and habitat. The renal corpuscles are aligned along the intrarrenal arteries. The urinary pole shows a siphon-like neck segment (NS) in 92% of the nephrons, whose structural characteristics are different from those of other fish. The podocytes have cuboidal cellular bodies, intercellular contacts, and poorly developed cell processes. The podocyte glycocalyx contains N-acetylglucosamine and lacks sialic acid. The structural and lectin-binding patterns are similar to those found in the immature mammalian kidney. The glomerular basement membrane (GBM) is very thick and consists of three layers: a lamina rara externa, a lamina densa, and a thick subendothelial lamina. The latter contains tubular microfibrils, collagen fibers, and long mesangial cell processes. Frequently, the podocyte bodies attach directly to the GBM, and the area occupied by the filtration slits is very small. Furthermore, the GBM shows a glycosylation pattern different from that observed in most vertebrates. Contrary to what would be expected in sturgeons living in freshwater, the A. nacarii renal corpuscle morphology suggests a low glomerular filtration rate. Anat Rec Part A 272A: 563,573, 2003. © 2003 Wiley-Liss, Inc. [source] Sequence of the Cenozoic Mammalian Faunas of the Linxia Basin in Gansu, ChinaACTA GEOLOGICA SINICA (ENGLISH EDITION), Issue 1 2004DENG Tao Abstract In the Linxia Basin on the northeast margin of the Tibetan Plateau, the Cenozoic strata are very thick and well exposed. Abundant mammalian fossils are discovered in the deposits from the Late Oligocene to the Early Pleistocene. The Dzungariotherium fauna comes from the sandstones of the Jiaozigou Formation, including many representative Late Oligocene taxa. The Platybelodon fauna comes from the sandstones of the Dongxiang Formation and the conglomerates of the Laogou Formation, and its fossils are typical Middle Miocene forms, such as Hemicyon, Amphicyon, Platybelodon, Choerolophodon, Anchitherium, and Hispanotherium. The Hipparion fauna comes from the red clay of the Liushu and Hewangjia Formations, and its fossils can be distinctly divided into four levels, including three Late Miocene levels and one Early Pliocene level. In the Linxia Basin, the Hipparion fauna has the richest mammalian fossils. The Equus fauna comes from the Wucheng Loess, and it is slightly older than that of the classical Early Pleistocene Nihewan Fauna. The mammalian faunas from the Linxia Basin provide the reliable evidence to divide the Cenozoic strata of this basin and correlate them with European mammalian sequence. [source] The treatment of uveal melanoma with iodine plaque brachytherapyACTA OPHTHALMOLOGICA, Issue 2009T KIVELÄ Purpose To provide an overview of managing uveal melanoma (UM) with iodine brachytherapy (IBT). Methods Personal experience of the author in using IBT since 1990. Results IBT is an effective option for managing a UM of any size, although it is mostly used for medium-sized tumours, preference being given to ruthenium brachytherapy (RBT) when the tumour is <5-6 mm thick and to transscleral local resection when thickness is >6 mm, especially when vision is good. IBT is also a safe alternative to enucleation of large UM >10 mm in thickness if the patient is keen to preserve the eye and motivated to accept eventual complications. The plaque is positioned over the UM with a 1-2 mm safety margin when using a collimated/rimmed plaque. Because of stray radiation, a safety margin is not mandatory when the plaque is non-collimated/non-rimmed. Otherwise, surgical technique does not differ from RBT. An advantage of IBT is that the radioactive seeds are separate from the plaque, allowing economical use of plaques of many different sizes and shapes and individual positioning of the seeds in a conformal way. A disadvantage is a short half-life; the seeds need to be changed every 6 months. The dose the author uses is 80 Gy to tumour apex, which is reduced on an individual basis to 60-70 Gy when the UM is very thick. Local tumour control rate is 90% and, paradoxically, not worse for large UM as compared to smaller ones. There are no unequivocal safety distances for avoiding radiation cataract, maculopathy and optic neuropathy, which are more or less frequent depending on the size and location of the UM. Conclusion IBT achieves good local tumour control of UM of all sizes, but preservation of vision is decidedly less frequent than after RBT, which is always given preference. [source] Keratocyte repopulation in UVB-exposed thioltransferase knockout miceACTA OPHTHALMOLOGICA, Issue 2007A PODSKOCHY Purpose: Thioltransferase is involved in cell protein homeostasis and DNA synthesis. It inhibits apoptosis and stimulates cell proliferation. Keratocyte repopulation after ultraviolet B (UVB) damage was studied in corneas of thioltransferase (-/-) mice. Methods: Six wild type mice and six thioltransferase (-/-) mice corneas were exposed at 300 nm UV-radiation at a dose producing damage in the corneal stroma (8 kJ/m2). Animals were killed 3 and 7 days after exposure. Corneas were processed for light microscopy. Results: All corneas of wild type mice and thioltransferase (-/-) mice showed extensive damage 3 days after UVB exposure. Keratocytes disappeared throughout the entire thickness of the UVB-damaged central stroma. Corneal thickness was nearly doubled compared with non-treated control corneas. However, 7 days after UVB exposure corneas of wild type mice were almost completely repopulated by keratocytes, only superficial ¼ of the stroma was still free of keratocytes. Corneal thickness was almost normal. Corneal stroma in the thioltransferase (-/-) mice 7 days after UV exposure was still not repopulated by keratocytes and the corneas were still very thick. Conclusions: The keratocyte repopulation in thioltransferase (-/-) mice is delayed. Thioltransferase seems to play an important role in the corneal wound healing and keratocyte repopulation after UVB induced damage. [source] | |||||||||||||