A magnetic attachment is a recently developed denture retaining device using the magnetic attractive force of the rare earth magnet. Magnetic attachments provide very specific dynamic characteristics and many valuable clinical advantages compared with conventional mechanical retainers. The present report aims at providing a general survey of this unique clinical system in dentistry, emphasizing the value of the finite element method.
A specimen collected years ago by Tatsuo Muramoto from Loc. Ik 1038 in the Ikushunbetsu Valley, central Hokkaido, was temporarily labeled as Neocardioceras(?) sp., without description. It is restudied on the basis of a review of previous works. As a result, it is now recognized as representing a new species of Neocardioceras, named N. muramotoi, sp. nov. The previously known species of Neocardioceras from various regions of the world can be arranged in five biostratigraphic zones of the upper part of the Cenomanian Stage (Cretaceous) in the tripartite scale. On the ground of biostratigraphic correlation, N. muramotoi is assigned to the Zone of Metoicoceras geslinianuin-Euomphalocerasseptemseriatum in the middle part of the Upper Cenomanian Substage. In this zone no species of Neocardioceras has been recognized previously.
The Kamimura River, an upper tributary of the Yahagi River, flows through steep valleys in the mountainous Kamiyahagi area of Gifu Prefecture. The Tokai Gou flood of September 11-12, 2000 destroyed embankments along the river, and exposed sedimentary layers at Umi that are typical of a lacustrine depositional setting. This confirms the existence of a paleo-lake from which the name Umi originated. The lake was formed as the result of a huge landslide that dammed up the Kamimura River. To determine when the landslide occurred, radiocarbon (14C) ages of trees buried in lacustrine sediments were determined using accelerator mass spectrometry (AMS). The 14C ages are 300±25, 340±25, 345±25 and 380±25 BP for the outermost rings of tree trunks, which include bark, and a single age of 620±25 BP. Calibrated ages of (1637), (1520, 1590, 1624), (1517, 1597, 1619) and (1482) cal AD within a range of 1455-1643 cal AD are consistent with a landslide triggered by the Tensho Earthquake of January 18, 1586, which had an estimated magnitude of 8.2-8.3 and an epicenter in Ise Bay.
By using a visual method of presenting DNA sequences (Makino, S., Amano, N., and Suzuki, M., 1999, Proc. Japan Acad. 75B, 311-316), genomic sequences of various organisms have been analyzed, including of a draft sequence of human genome (International Human Genome Sequencing Consortium, 2001, Nature 409, 860-921). It is concluded that, with an increase in the number of basepairs in a genome, a tendency becomes clearer for clustering of A:T pairs and G:C pairs separately into regions of 0.5-5K basepairs in length. It is likely that these regions have important functions for regulating transcription of the increasing number of genes coded and for organizing replication of the increasing length of genomic DNA.
We have developed a simple method, designated as Gene Specific-Primer Extension Preamplification (GS-PEP), to increase the copy number of genomic DNA fragments for a gene of interest prior to PCR amplification. In this method, multiple cycles of primer-extension reaction are undertaken in a single tube using a mixture of primers derived from a defined strand of DNA sequences covering a gene. After 50 cycles of GS-PEP against 21pg of genomic DNA, which corresponds to approximately 3 copies of diploid human genome DNA, with a mixture of 6 primers for the p53 gene locus, all the 10 coding exons of the p53 gene were readily amplifiable by standard PCR at rates of 100%. In contrast, direct PCR against 21pg of genomic DNA was estimated to allow the amplification of only 3 exons. This procedure also enhanced the rate of amplification by PCR using genomic DNA extracted from formalin-fixed and paraffin-embedded tissues. Thus, GS-PEP would allow mutation analyses of various genes in cancer cells using small amounts and/or low qualities of DNA.