3,255 research outputs found
Suppressing breakers with polar oil films : using an epic sea rescue to model wave energy budgets
© The Author(s), 2017. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Geophysical Research Letters 44 (2017): 1414â1421, doi:10.1002/2016GL071505.Oil has been used to still stormy seas for centuries, but the mechanisms are poorly understood. Here we examine the processes by using quantitative information from a remarkable 1883 sea rescue where oil was used to reduce large breakers during a storm. Modeling of the oil film's extent and waves under the film suggests that large breakers were suppressed by a reduction of wind energy input. Modification of surface roughness by the film is hypothesized to alter the wind profile above the sea and the energy flow. The results are central to understanding air-sea momentum exchange, including its role in such processes as cyclone growth and storm surge, although they address only one aspect of the complex problem of wind interaction with the ocean surface.TFD was partially
supported by ONR MURI grant N00014-
11-1-0701
Bacterial leakage around dental restorations: its effect on the dental pulp
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/72129/1/j.1600-0714.1982.tb00188.x.pd
The Caries Phenomenon: A Timeline from Witchcraft and Superstition to Opinions of the 1500s to Today's Science
This historical treatise follows the documented timeline of tooth decay into today's understanding, treatment, and teaching of caries biology. Caries has been attributed to many different causes for several millennia, however, only since the late 1900s has research revealed its complex multifactorial nature. European writers of the 1600s to 1700s held views that general health, mechanical injuries, trauma, and sudden temperature changes all caused cariesâholding a common belief that decay was due to chemical agents, faulty saliva, and food particles. Until the early 1800s most writers believed that caries was due to inflammation from surrounding diseased alveolar bone. Today's science has demonstrated that caries is caused by indigenous oral microorganisms becoming a dynamic biofilm, that in the presence of fermentable sugars produce organic acids capable of dissolving inorganic enamel and dentin followed by the proteolytic destruction of collagen leaving soft infected dentin. As bacteria enter the pulp, infection follows
Histopathologic evaluation of the effects of four calcium hydroxide liners on monkey pulps
Pulpal response of four calcium hydroxide liners, MPC 10Âź, MPC 12Âź, DycalÂź and PulpdentÂź were tested on primary and permanent teeth with zinc oxide and eugenol (ZOE) and silicate as controls. Responses of the pulps were evaluated in Rhesus monkeys, utilizing Class V cavity preparations at 3 days, 5 and 8 weeks. An equivalent number of anterior and posterior teeth were studied for all compounds. The Ca(OH) 2 liners, zinc oxide and eugenol (ZOE) and silicate controls were placed in 80 primary and 80 permanent teeth. Following perfusions the teeth were prepared utilizing routine histological procedures. The 3 day response of the calcium hydroxides was moderate with some disruption in the odontoblasts, vacuolization and mild inflammation underlying the cavity except Pulpdent which was more severe. At 5 weeks a decrease in inflammatory response and the formation of reparative dentin was similar for all calcium hydroxides tested at this time period. At 8 weeks more reparative dentin was noted with slight to moderate pulpal responses. At all time periods ZOE produced the least pulpal response while silicate produced the most severe response at 5 and 8 weeks. This study reports the biological responses of four calcium hydroxide compounds used as cavity liners in non-exposures in a series of primary and permanent teeth of monkeys using ZOE and silicate as controls. Responses to the four Ca(OH) 2 compounds were moderate for all the experimental compounds except Pulpdent which was more severe at the early time period tested. ZOE produced a milder and silicate a severe response at all periods. All of these compounds were placed by random selection in anterior and posterior teeth of both arches and five teeth were evaluated in both primary and permanent teeth at 3 days, 5 and 8 weeks.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/74743/1/j.1600-0714.1976.tb01759.x.pd
Histopathologic Evaluation of three Ultraviolet-Activated Composite Resins on Monkey pulps
The pulpal responses of three ultraviolet-activated composite resins, Nuva-FilÂź, Experimental UV #1Âź and Experimental UV #2Âź, were tested on adult monkey teeth using silicate and zinc oxide eugenol (ZOE) as positive and negative controls. All materials were placed in Class V cavity preparations in Rhesus monkey teeth using approximately 48 anterior and 63 posterior teeth of both the maxillary and mandibular arches. A total of 111 teeth were utilized and all materials were evaluated at 3 days, 5 and 8 weeks. Following left ventricular perfusion, the teeth were prepared for microscopic evaluation using routine histological procedures. The 3-day pulpal response of all the ultraviolet-activated composites was slight with some disruption and vacuolization in the odontoblastic layer and a slight inflammatory response. At 5 weeks there was a reduction of the inflammatory response and the formation of reparative dentin was noted for all ultraviolet composites. The 8-week pulp response was slight, characterized by a minimal inflammatory response adjacent to the zone of reparative dentin. Generally, ZOE produced the mildest response while silicate produced the most severe response at the three time intervals.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/74732/1/j.1600-0714.1977.tb01797.x.pd
The extent of the odontoblast process in rhesus monkeys (Macaca mulatta) as observed by scanning electron microscopy
Monkeys were perfused with Karnovsky phosphate-buffered formalin-glutaraldehyde (PBF-GTA). Molars were removed and postfixed in PBF-GTA, demineralized in EDTA, freeze-fractured, and critical-point dried. Odontoblast processes were observed in tubules of the predentine, the pulpal inner third of dentine and in the peripheral dentine, but not in the middle third. Peripheral processes showed close adaptation to dentinal tubules with branches penetrating into canaliculi close to the dentine-enamel junction.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/24576/1/0000859.pd
Early Neoproterozoic Basin Formation in Yukon, Canada: Implications for the make-up and break-up of Rodinia
SUMMARY: Geological mapping and stratigraphic anaylsis of the early Neoproterozoic Fifteenmile Group in the western Ogilvie Mountains of Yukon, Canada, has revealed large lateral facies changes in both carbonate and siliciclastic strata.  Syn-sedimentary NNW-side-down normal faulting during deposition of the lower Fifteenmile Group generated local topographic relief and wedge-shaped stratal geometries. These strata were eventually capped by platformal carbonate after the establishment of a NNW-facing stromatolitic reef complex that formed adjacent to the coeval Little Dal Group of the Mackenzie Mountains, Northwest Territories. Correlations between specific formations within these groups are tested with carbon isotope chemostratigraphy.  As there are no known 830-780 Ma stratigraphic successions south of 62°N, the basin-forming event that accommodated the Fifteenmile and Little Dal Groups of the Ogilvie and Mackenzie Mountains and equivalent strata in the Shaler Supergroup of Victoria Island was restricted to the northwest margin of Laurentia. Therefore, this event does not represent widespread rifting of the entire western margin of Laurentia and instead we propose that these strata were accommodated in a failed rift generated by localized subsidence associated with the emplacement of the coeval Guibei (China) and Gairdner (Australia) large igneous provinces. The northern margin of Laurentia was reactivated by renewed extension at ca. 720 Ma associated with the emplacement of the Franklin large igneous province.  Significant crustal thinning and generation of a thermally subsiding passive margin on the western margin of Laurentia may not have occurred until the late Ediacaran.RĂSUMĂLe cartographiage gĂ©ologique et lâanalyse stratigraphique du groupe nĂ©oprotĂ©zoĂŻque Fifteenmile situĂ© Ă lâouest des montagnes Ogilvie du Yukon, Canada, ont rĂ©vĂ©lĂ© de grands changements latĂ©raux de faciĂšs Ă la fois pour les strates carbonatĂ©es et silicoclastiques. La mise en place des failles normales syn-sĂ©dimentaires inclinĂ©es vers le NNW au cours du dĂ©pĂŽt du groupe Fifteenmile infĂ©rieur, a entrainĂ© la formation locale dâun relief topographique et une prisme des strates. Ces derniĂšres ont finalement Ă©tĂ© recouvertes de carbonates de plate-forme issus de la mise en place dâun complexe rĂ©cifal stromatolitique exposĂ© NNW contigu Ă la formation de mĂȘme Ăąge du groupe Little Dal des montagnes Ogilvie, en Territoires du Nord-Ouest. Les corrĂ©lations existant entre des formations spĂ©cifiques de chacun de ces groupes, sont testĂ©es grĂące Ă la chimiostratigraphie des isotopes du carbone. Aucunes successions stratigraphiques agĂ©es de 830-780 Ma nâĂ©tant connues au sud de 62° N, la formation du bassin oĂč sont accumulĂ©s les groupes Fifteenmile et Little Dal des massifs Ogilvie et Mackenzie, ainsi que les strates analogues du supergroupe Shaler de lâĂźle Victoria, Ă©tait restreinte Ă la bordure nord-ouest de la Laurentie. De ce fait, cet Ă©vĂ©nement ne correspond pas au large rifting sâĂ©tendant sur lâentiĂšre bordure ouest de la Laurentie et nous proposons Ă la place, que ces strates ont Ă©tĂ© localisĂ©es au cours dâun rift avortĂ© gĂ©nĂ©rĂ© par la mise en place simultanĂ©e des larges provinces ignĂ©es Guibei (Chine) et Gairdner (Australie). La bordure nord de la Laurentie a Ă©tĂ© rĂ©activĂ©e par une nouvelle phase dâextension Ă ca. 720 Ma associĂ©e Ă lâemplacement de la province ignĂ©e Franklin. Lâamincissement crustal et la formation dâune marge passive thermiquement subsidente le long de la bordure ouest de la Laurentie ne se sont certainement pas produits avant lâĂdiacarien supĂ©rieur
The effects of combined nerve resection and cavity preparation and restoration on response dentine formation in rabbit incisors
This study was carried out to determine the effects of nerve resection and cavity preparation with restoration (CPR) on the formation of response dentine in continually developing rabbit incisor teeth. Resections of the inferior alveolar nerve (IAN) and/or the superior cervical ganglion (SCG) were performed on the right side of 42 adult New Zealand rabbits. Fifteen days were allowed for neural degeneration, after which uniform CPR were placed in both resected and adjacent normal incisors. Half of the operated animals were killed 14 days after CPR placement and the second half, 35 days after. Both radiographic and histological evidence revealed a dramatic increase in dentine deposition following IAN and IAN-SCG with CPR both 14 and 35 days after cavity preparation. The pulps of these neural-resected and CPR incisors were small and limited to the growing end of the tooth. Most of the newly formed dentine appeared regular and without defects; however, the dentine found at the apex was distorted with the appearance of osteodentine. At 14 and 35 days after CPR, the SCG-resected incisors showed no more response dentine formation than adjacent non-resected teeth. Radiographic and histologic appearance of CPR treated incisors indicated they were comparable in size and morphology to the controls.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/22327/1/0000772.pd
Specific Etiologies Associated With the Multiple Organ Dysfunction Syndrome in Children: Part 2
To describe a number of conditions and therapies associated with multiple organ dysfunction syndrome (MODS) presented as part of the Eunice Kennedy Shriver National Institute of Child Health and Human Development MODS Workshop (March 26â27, 2015). In addition, the relationship between burn injuries and MODS is also included although it was not discussed at the Workshop
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