A marker tephra bed close to the Lower-Middle Pleistocene boundary: Distribution of the Ontake-Byakubi Tephra Bed in central Japan

Tephrochronology is an exceptionally important tool in the precise regional correlation of Early and Middle Pleistocene sedimentary strata in Japan. The present study reveals that the Yukawa tephra 5 (YUT5) derived from the Older Ontake volcano, the Nezumigawa (Nzg) and Mitamitajima (Mtj) tephras of the Ina Bazin, and the Byakubi-E tephra (Byk-E) of the Boso Peninsula are the same tephra on the basis of their lithofacies, bulk grain composition, mafic mineral composition, major element composition of hornblende, and stratigraphic relationships with the dated tephras. We propose to call the series of tephras correlated with Byk-E the Ontake-Byakubi Tephra Bed (On-Byk Tephra) following the naming convention in which the tephra name consists of the names of the source volcano and the type location. The Matuyama-Brunhes Chronozone boundary occurs just above Byk-E in the type section of the Kokumoto Formation in the Kazusa Group, which is a candidate Global Boundary Stratotype Section and Point (GSSP) for the lower boundary of the Middle Pleistocene Subseries. Therefore, On-Byk Tephra becomes a critically important marker tephra bed for the Early-Middle Pleistocene boundary in central Japan. The present study indicates that the major element composition of hornblende can be a useful tool for identification and correlation of strongly weathered tephra layers such as Nzg and Mtj in which all the volcanic glass shards have been altered.ArticleQuaternary International. 397: 27-38(2016)journal articl

Analysis of Difficult Tracheal Intubation Based on Video Records Using a Macintosh Type Video Intubating Laryngoscope in Adult

To assess the incidence of the difficult intubation and evaluate its clinical characteristics, we analyzed 964 cases of video records of tracheal intubation by Macintosh type video laryngoscope (MVL; X-Lite video^[○!R]: Rusch, Germany). The views during the laryngoscopy were recorded on a video system, and the number of intubation attempts and total attempt times were measured afterwards. The video laryngoscope grade (V-grade) was determined based on the Cormack & Lehane grade (C-grade), and its correlation with the Mallampati classes (MP), the number of intubation attempts, and total attempt time were analyzed. V-grade 3 was defined as a difficult intubation, and morphological measurement of the head and neck regions was performed postoperatively. Of the 964 patients, 522, 416, and 26 patients were classified into V-grade 1, 2 and 3, respectively, and the number and time of attempts significantly increased with the grade (p<0.05). The V-grades were significantly correlated with the MP classes and the number and time of attempts (p<0.0001). At least 1 of the 3 morphological measurement items was abnormal in the 26 patients with difficult intubation in visual assistance and recognition. The use of MVL might facilitate difficult intubation. Its video records were useful for analysis. The postoperative morphological feature was consistent with previous reports where MVL was not used

Cognitive and Socio-Emotional Deficits in Platelet-Derived Growth Factor Receptor-β Gene Knockout Mice

Platelet-derived growth factor (PDGF) is a potent mitogen. Extensive in vivo studies of PDGF and its receptor (PDGFR) genes have reported that PDGF plays an important role in embryogenesis and development of the central nervous system (CNS). Furthermore, PDGF and the β subunit of the PDGF receptor (PDGFR-β) have been reported to be associated with schizophrenia and autism. However, no study has reported on the effects of PDGF deletion on mice behavior. Here we generated novel mutant mice (PDGFR-β KO) in which PDGFR-β was conditionally deleted in CNS neurons using the Cre/loxP system. Mice without the Cre transgene but with floxed PDGFR-β were used as controls. Both groups of mice reached adulthood without any apparent anatomical defects. These mice were further examined by conducting several behavioral tests for spatial memory, social interaction, conditioning, prepulse inhibition, and forced swimming. The test results indicated that the PDGFR-β KO mice show deficits in all of these areas. Furthermore, an immunohistochemical study of the PDGFR-β KO mice brain indicated that the number of parvalbumin (calcium-binding protein)-positive (i.e., putatively γ-aminobutyric acid-ergic) neurons was low in the amygdala, hippocampus, and medial prefrontal cortex. Neurophysiological studies indicated that sensory-evoked gamma oscillation was low in the PDGFR-β KO mice, consistent with the observed reduction in the number of parvalbumin-positive neurons. These results suggest that PDGFR-β plays an important role in cognitive and socioemotional functions, and that deficits in this receptor may partly underlie the cognitive and socioemotional deficits observed in schizophrenic and autistic patients