Chapter 5 : Deciduous Tooth Resorption after Overfilling of Root Canal Filler: Function and Nature of Multinucleated Giant Cells

There are numerous reports on physiological root resorption claiming that the root resorption process of primary teeth is regulated in a manner similar to bone remodeling [28]. However, complex histological changes occur under several pathological conditions. Abnormal tooth resorption could be found in primary teeth due to certain causes until the completion of the permanent dentition. In Japan and eastern Asia, calcium hydroxide paste with silicon oil added iodoform is widely used for endodontic treatment of deciduous teeth. This material is sometimes excessively filled within root canals, and pathological reactions have been already discussed in previous sections. In this part, the influences on deciduous tooth endodontic therapy will be described in detail. The most characteristic feature is abnormal tooth resorption via osteoclast-like multinucleated giant cells (MGCs) and foreign body giant cells (FBGCs). In the later part of this section, the characteristics of foreign body type giant cells will be discussed through in vivo experiments.Editor, Toshiyuki KawakamiLanguage Editor, David M Carlsonviii, 232 p. ill. (some col.

Formation of x-ray Newton’s rings from nano-scale spallation shells of metals in laser ablation

The initial stages of the femtosecond (fs) laser ablation process of gold, platinum, and tungsten were observed by single-shot soft x-ray imaging technique. The formation and evolution of soft x-ray Newton’s rings (NRs) were found for the first time. The soft x-ray NRs are caused by the interference between the bulk ablated surface and nanometer-scale thin spallation layer; they originate from the metal surface at pump energy fluence of around 1 J/cm2 and work as a flying soft x-ray beam splitter

術後性上顎嚢壁にみられた石灰化物の観察

Light and scanning electron microscopic observations and electron probe microanalysis were carried out on granular calcified bodies that appeared in the wall of a postoperative maxillary cyst in a 59-year-old man. The granular bodies, stained slightly with hematoxylin, were scattered in the cyst wall. They reacted positively to von Kossa\u27s stain indicating calcification. Based on scanning electron microscopic observation, secondary electron images revealed them to be compact bodies, and they appeared as light spots in composition images. Electron probe microanalysis revealed that the bodies were ccomposed mainly of calcium and phosphorus. Some of the large bodies had a membranous calcification core, which was observed especially in von Kossa\u27s stained specimens. Therefore, we believe that these calcification core must be generated cell debris, cell membrane, nuclear membrane or subcellular organelles

Mid-Quaternary Paleoceanographic Trend in Near-shore Waters of the Northwest Pacific : A Case Study Based on an Offshore Well

application/pdfAn exploratory oil and gas well was drilled on the continental shelf in water 38 m deep at lat. 36°9′33.8″N., long. 140°43′49.3″E., 13 km off the coast of Kashima, Ibaraki Prefecture, Kanto District, Japan. This well sank to the total subbottom depth of 2100 m penetrated sediments ranging back to Late Cretaceous in age. The upper 500 m of well sequence which comprises largely Quaternary sediments was subjected to paleoenvironmental analyses by jointly analyzing microfossils (calcareous nannoplankton and benthic and planktonic foraminifera), mineral content, and oxygen and carbon isotope stratigraphies. Three dated horizons, 0.128, 0.27 and 0.46 Ma, were established by recognizing one marked excursion to negative values in the oxygen isotope record and two calcareous nannoplankton datum levels in the well sequence. A possible hiatus at about 465 m depth terminates this mid-Quaternary sequence which is underlain by late Pliocene strata of about 1.9 Ma and older. Mid-Quaternary paleobathymetric trends were reconstructed for the well site area mainly on the basis of Q-mode cluster analysis of benthic foraminiferal faunas. Deposition of the mid-Quaternary sequence began in the upper bathyal zone and a steady shallowing followed through outer shelf environments to the present-day inner neritic zone. Other paleo-depth indicators such as abundance variations of nannoplankton Florisphaera profuuda and planktonic versus total foraminifera ratios, and variations of ^C isotope record are all supportive of this benthic foraminifera-based depth-trend. Paleotemperature fluctuations were estimated by analyzing oxygen isotope compositions of benthic and planktonic foraminifera and by calculating with the aid of paleoecological transfer functions quantitative estimates of past winter temperatures. The paleotemperature fluctuations estimated for the well site area by these two methods agree well for the lower part of the well sequence, but begin to diverge from the mid-sequence and upwards, probably reflecting increasing effects of local water masses to the oxygen isotope variation. In the Quaternary isotope record of Kashima SK-1 well, no definite interval correlatable with the even-numbered isotope stages was observed. In view of the fact that distinct hiatuses occur in the onshore Quaternary record of Kanto District located to the west of the well site, the lack of even-numbered isotope stages is interpreted to signify periods of greatly reduced sedimentation or possibly non-deposition in a broad coastal region encompassing also the continental shelf around the well site. Mid-Quaternary paleoceanography around the well site prior to about 0.35 Ma was under the general influence of cold Oyashio Current with its strength varying greatly from time to time, whereas the latter time period responding to the diminishing Oyashio Current saw a seesaw game of two warm currents, Kuroshio and Tsugaru, expanding and retreating alternatively over a broad region of the sea off Northeast Honshu, Japan.紀要類(bulletin)3178679 bytesdepartmental bulletin pape

Formation of x-ray Newton’s rings from nano-scale spallation shells of metals in laser ablation

The initial stages of the femtosecond (fs) laser ablation process of gold, platinum, and tungsten were observed by single-shot soft x-ray imaging technique. The formation and evolution of soft x-ray Newton’s rings (NRs) were found for the first time. The soft x-ray NRs are caused by the interference between the bulk ablated surface and nanometer-scale thin spallation layer; they originate from the metal surface at pump energy fluence of around 1 J/cm2 and work as a flying soft x-ray beam splitter