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  • 1
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    Chemostratigraphic Correlations of Deep-Sea Sediments in the Western North Pacific Ocean: A New Constraint on the Distribution of Mud Highly Enriched in Rare-Earth Elements
    MDPI AG ; 2020
    In:  Minerals Vol. 10, No. 6 ( 2020-06-26), p. 575-
    Details
    In: Minerals, MDPI AG, Vol. 10, No. 6 ( 2020-06-26), p. 575-
    Abstract: Deep-sea sediments with total rare-earth elements and yttrium (ΣREY) concentrations exceeding 400 ppm, which are termed REY-rich mud, are widely distributed in the world oceans. Specifically, deep-sea sediments within the Japanese exclusive economic zone (EEZ) surrounding Minamitorishima Island in the western North Pacific have attracted significant attention as a new REY resource, because they contain REY-enriched layers exceeding 2000 ppm of ΣREY. However, neither the sediments deeper than 15 m below the seafloor (mbsf) nor those outside the Minamitorishima EEZ have ever been studied. Recently, a number of distinct geochemical features which are aligned in stratigraphic order were recognized in these sediments, based on multi-elemental composition data. Chemostratigraphy enables us to laterally correlate three REY peaks among apparently featureless pelagic clays. Here, we apply chemostratigraphic correlation to 19 new cores collected from the northern Pigafetta Basin and several small basins within the Marcus-Wake Seamounts. This study revealed that the REY-enriched layers occur at greater depths than the piston core length in a wider area than previously investigated (e.g., ~20.5 mbsf at Ocean Drilling Program Site 801A). This finding suggests that the depositional environments in these areas were basically similar, although local geographic conditions could have affected the continuity of REY peaks.
    Type of Medium: Online Resource
    ISSN: 2075-163X
    URL: Article
    DOI: 10.3390/min10060575
    Language: English
    Publisher: MDPI AG
    Publication Date: 2020
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  • 2
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    Intermittent Beginning to the Formation of Hydrogenous Ferromanganese Nodules in the Vast Field: Insights from Multi-Element Chemostratigraphy Using Microfocus X-ray Fluorescence
    MDPI AG ; 2021
    In:  Minerals Vol. 11, No. 11 ( 2021-11-10), p. 1246-
    Details
    In: Minerals, MDPI AG, Vol. 11, No. 11 ( 2021-11-10), p. 1246-
    Abstract: Vast ferromanganese nodule fields have been found on the deep-sea floor of all oceans worldwide. They have received attention because they potentially provide high-grade metal resources to develop future high- and green-technology. However, how these vast nodule fields were formed and developed owing to their widespread nature or tendency to be denser with an increasing number of nodules has not yet been established. In this study, the fine-scale inner structure of nodules of various sizes was analyzed on the basis of chemical mapping using microfocus X-ray fluorescence. We found that nodules distributed in the vast field around Minamitorishima (Marcus) Island have several types of innermost layers, which correspond to different chemostratigraphic layers of nodules that have been previously reported by us in this region. As nodules grow in order from the center to the outside, the different types in the innermost layer indicate a difference in the timing of the beginning of their growth. Moreover, because the differences in the chemical features of each layer reflect differences in the composition of the original deep-sea water, our results imply that the beginning of nodule formation occurred intermittently at each time of a water mass replacement due to new deep-sea currents flowing into this region. We recognized that the northern part of the study area was dominated by large nodules that started to grow in relatively earlier times, while the southern part tended to have many nodules that grew in relatively later times. Based on these observations, we hypothesize that the intermittent beginning of nodule formation is governed by the northward inflow of the deep-sea current that originated from the Lower Circumpolar Deep Water for an extended time to form the vast nodule field. Because patterns in the timing of nodule formation were different in the eastern and western regions, we thus further propose that the topographic framework, i.e., the arrangement of individual large seamounts and the cluster of small knolls and petit-spot volcanoes, strongly regulates the flow path of the deep-sea current, even if the position of the entire seamount changes owing to plate motion. The deep-sea current might supply some materials to be nuclei, resulting in the nodule formation at the beginning of the process.
    Type of Medium: Online Resource
    ISSN: 2075-163X
    URL: Article
    DOI: 10.3390/min11111246
    Language: English
    Publisher: MDPI AG
    Publication Date: 2021
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  • 3
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    87Sr/86Sr Isotopic Ratio of Ferromanganese Crusts as a Record of Detrital Influx to the Western North Pacific Ocean
    MDPI AG ; 2022
    In:  Minerals Vol. 12, No. 8 ( 2022-07-27), p. 943-
    Details
    In: Minerals, MDPI AG, Vol. 12, No. 8 ( 2022-07-27), p. 943-
    Abstract: In this study, the Sr isotope ratios (IRs; 87Sr/86Sr) of ferromanganese (Fe–Mn) crusts are analyzed through laser ablation inductively coupled plasma multiple-collector mass spectrometry. A sample collected from off Minamitorishima Island showed uniform Sr IRs (0.70906–0.70927) similar to that of present-day seawater with more than 36 mm thickness. Meanwhile, a detritus-rich sample collected from off northeast (NE) Japan showed a wide variation in Sr IRs (0.707761–0.709963). The Sr IR variation in the Fe–Mn crust from off NE Japan suggests detrital influx contributions from both the NE Japan arc ( 〈 0.708) and aeolian dust from China ( 〉 0.718). Detrital flux from the NE Japan arc increases from the bottom to middle layers, possibly due to the uplift of the Ou backbone range that occurred after ~2 Ma. The increased influx of the aeolian dust in the outer layer is attributable to global cooling in the Quaternary that increased the loess dust transportation from China to the western North Pacific Ocean. Meanwhile, the influence of the detrital influx on the sample from off Minamitorishima Island appeared to be negligible. The Sr IR analysis with high spatial resolution proposed in this study possibly improves the burial history of Fe–Mn nodules.
    Type of Medium: Online Resource
    ISSN: 2075-163X
    URL: Article
    DOI: 10.3390/min12080943
    Language: English
    Publisher: MDPI AG
    Publication Date: 2022
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  • 4
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    X-ray Computed Tomography Analysis of Ferromanganese Nodule Nuclei from the Western North Pacific Ocean: Insights into Their Origins
    MDPI AG ; 2023
    In:  Minerals Vol. 13, No. 6 ( 2023-05-23), p. 710-
    Details
    In: Minerals, MDPI AG, Vol. 13, No. 6 ( 2023-05-23), p. 710-
    Abstract: Ferromanganese nodule nuclei are considered crucial to the formation and distribution of nodules. However, because it is difficult and time-consuming to study ferromanganese nodule nuclei, few studies have been performed, despite the large number of samples. Here, we analyzed the nuclei of 934 ferromanganese nodules from the abyssal seafloor around Minamitorishima Island (western North Pacific Ocean) using X-ray computed tomography (CT). Based on the CT number distribution (describing X-ray absorption in Hounsfield units, HU), we classified the nuclei as Type I ( 〉 1800 HU) or Type II ( 〈 1800 HU). Additionally, some Type I nuclei had characteristic conical shapes (Type I-C) distinct from the shapes of other nuclei (Type I-O). Based on the chemical compositions determined by microfocus X-ray fluorescence analyses of selected samples, we identified Type I-C, I-O, and II nuclei as fish teeth, hard rocks (volcanic rock, ironstone, or phosphorite), and sediments, respectively. These nucleus types were observed in sufficient quantities at all dive sites that we conclude them to be typical of nodule nuclei in the study area. Fish-tooth nuclei were the rarest at all sites, whereas sediment nuclei dominated at most sites, suggesting their significance for understanding the origin of ferromanganese nodules. Hard-rock nuclei dominated at only three sites and probably originated from seamounts.
    Type of Medium: Online Resource
    ISSN: 2075-163X
    URL: Article
    DOI: 10.3390/min13060710
    Language: English
    Publisher: MDPI AG
    Publication Date: 2023
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  • 5
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    MiR-10a in Pancreatic Juice as a Biomarker for Invasive Intraductal Papillary Mucinous Neoplasm by miRNA Sequencing
    MDPI AG ; 2021
    In:  International Journal of Molecular Sciences Vol. 22, No. 6 ( 2021-03-22), p. 3221-
    Details
    In: International Journal of Molecular Sciences, MDPI AG, Vol. 22, No. 6 ( 2021-03-22), p. 3221-
    Abstract: New biomarkers are needed to further stratify the risk of malignancy in intraductal papillary mucinous neoplasm (IPMN). Although microRNAs (miRNAs) are expected to be stable biomarkers, they can vary owing to a lack of definite internal controls. To identify universal biomarkers for invasive IPMN, we performed miRNA sequencing using tumor-normal paired samples. A total of 19 resected tissues and 13 pancreatic juice samples from 32 IPMN patients were analyzed for miRNA expression by next-generation sequencing with a two-step normalization of miRNA sequence data. The miRNAs involved in IPMN associated with invasive carcinoma were identified from this tissue analysis and further verified with the pancreatic juice samples. From the tumor-normal paired tissue analysis of the expression levels of 2792 miRNAs, 20 upregulated and 17 downregulated miRNAs were identified. In IPMN associated with invasive carcinoma (INV), miR-10a-5p and miR-221-3p were upregulated and miR-148a-3p was downregulated when compared with noninvasive IPMN. When these findings were further validated with pancreatic juice samples, miR-10a-5p was found to be elevated in INV (p = 0.002). Therefore, three differentially expressed miRNAs were identified in tissues with INV, and the expression of miR-10a-5p was also elevated in pancreatic juice samples with INV. MiR-10a-5p is a promising additional biomarker for invasive IPMN.
    Type of Medium: Online Resource
    ISSN: 1422-0067
    URL: Article
    DOI: 10.3390/ijms22063221
    Language: English
    Publisher: MDPI AG
    Publication Date: 2021
    detail.hit.zdb_id: 2019364-6
    SSG: 12
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  • 6
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    Transcriptome Analysis Reveals Differential Gene Expression between the Closing Ductus Arteriosus and the Patent Ductus Arteriosus in Humans
    MDPI AG ; 2021
    In:  Journal of Cardiovascular Development and Disease Vol. 8, No. 4 ( 2021-04-16), p. 45-
    Details
    In: Journal of Cardiovascular Development and Disease, MDPI AG, Vol. 8, No. 4 ( 2021-04-16), p. 45-
    Abstract: The ductus arteriosus (DA) immediately starts closing after birth. This dynamic process involves DA-specific properties, including highly differentiated smooth muscle, sparse elastic fibers, and intimal thickening (IT). Although several studies have demonstrated DA-specific gene expressions using animal tissues and human fetuses, the transcriptional profiles of the closing DA and the patent DA remain largely unknown. We performed transcriptome analysis using four human DA samples. The three closing DA samples exhibited typical DA morphology, but the patent DA exhibited aorta-like elastic lamellae and poorly formed IT. A cluster analysis revealed that samples were clearly divided into two major clusters, the closing DA and patent DA clusters, and showed distinct gene expression profiles in IT and the tunica media of the closing DA samples. Cardiac neural crest-related genes such as JAG1 were highly expressed in the tunica media and IT of the closing DA samples compared to the patent DA sample. Abundant protein expressions of jagged 1 and the differentiated smooth muscle marker calponin were observed in the closing DA samples but not in the patent DA sample. Second heart field-related genes such as ISL1 were enriched in the patent DA sample. These data indicate that the patent DA may have different cell lineages compared to the closing DA.
    Type of Medium: Online Resource
    ISSN: 2308-3425
    URL: Article
    DOI: 10.3390/jcdd8040045
    Language: English
    Publisher: MDPI AG
    Publication Date: 2021
    detail.hit.zdb_id: 2777082-5
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  • 7
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    The Differential Prognostic Impact of Long-Duration Atrial High-Rate Episodes Detected by Cardiac Implantable Electronic Devices between Patients with and without a History of Atrial Fibrillation
    MDPI AG ; 2022
    In:  Journal of Clinical Medicine Vol. 11, No. 6 ( 2022-03-21), p. 1732-
    Details
    In: Journal of Clinical Medicine, MDPI AG, Vol. 11, No. 6 ( 2022-03-21), p. 1732-
    Abstract: Long-duration atrial high-rate episodes (AHREs) monitored using cardiac implantable electronic devices (CIEDs) can predict long-term major adverse cardiovascular events (MACEs). This study aimed to compare the impact of long-duration AHRE on MACE development between patients with and without a history of atrial fibrillation (AF). This single-center observational study included 132 CIED-implanted patients with AHREs detected via remote monitoring. The population was dichotomized into groups: with (n = 69) and without (n = 63) AF. In each group, cumulative incidences of MACEs comprising all-cause deaths, heart failure hospitalizations, strokes, and acute coronary syndromes were compared between patients with AHRE durations of ≥24 h and 〈 24 h. Multivariate analysis was performed to identify predictors of MACEs among patients without AF. MACE incidence was significantly higher in patients with AHRE ≥24 h than in those with 〈 24 h in the group without AF (92% vs. 30%, p = 0.005). MACE incidence did not significantly differ between AHRE ≥24 h and 〈 24 h in the group with AF (54% vs. 26%, p = 0.44). After a multivariate adjustment, AHRE duration of ≥24 h emerged as the only independent predictor of MACEs among patients without AF (p = 0.03). In conclusion, a long-duration AHRE was prognostic in patients without a history of AF but not in patients with a history of AHREs.
    Type of Medium: Online Resource
    ISSN: 2077-0383
    URL: Article
    DOI: 10.3390/jcm11061732
    Language: English
    Publisher: MDPI AG
    Publication Date: 2022
    detail.hit.zdb_id: 2662592-1
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  • 8
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    Single Crystal Growth of Sillén–Aurivillius Perovskite Oxyhalides Bi4NbO8X (X = Cl, Br)
    MDPI AG ; 2018
    In:  Inorganics Vol. 6, No. 2 ( 2018-04-16), p. 41-
    Details
    In: Inorganics, MDPI AG, Vol. 6, No. 2 ( 2018-04-16), p. 41-
    Type of Medium: Online Resource
    ISSN: 2304-6740
    URL: Article
    DOI: 10.3390/inorganics6020041
    Language: English
    Publisher: MDPI AG
    Publication Date: 2018
    detail.hit.zdb_id: 2735043-5
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  • 9
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    Railway Actuator Made of Magnetic Elastomers and Driven by a Magnetic Field
    MDPI AG ; 2018
    In:  Polymers Vol. 10, No. 12 ( 2018-12-06), p. 1351-
    Details
    In: Polymers, MDPI AG, Vol. 10, No. 12 ( 2018-12-06), p. 1351-
    Abstract: We fabricated a mono-link using bimodal magnetic elastomers that demonstrate drastic changes in the elastic modulus by magnetic fields. The magnetic elastomer is bimodal consisting of large magnetic particles and nonmagnetic fine particles. The storage modulus for bimodal magnetic elastomers was altered from 2.2 × 105 to 1.7 × 106 Pa by a magnetic field of 500 mT. Compression tests up to a strain of 20% also revealed that the on-field stress for the bimodal magnetic elastomer was 1.24 times higher than the off-field stress. The bimodal magnetic elastomer was synthesized for the mono-link and was mounted on the bogie of a railway vehicle. A running test exhibited that the wheel lateral force was reduced by 20% by applying a magnetic field of 390 mT.
    Type of Medium: Online Resource
    ISSN: 2073-4360
    URL: Article
    DOI: 10.3390/polym10121351
    Language: English
    Publisher: MDPI AG
    Publication Date: 2018
    detail.hit.zdb_id: 2527146-5
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  • 10
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    Survival Analysis in Patients with Pancreatic Ductal Adenocarcinoma Undergoing Chemoradiotherapy Followed by Surgery According to the International Consensus on the 2017 Definition of Borderline Resectable Cancer
    MDPI AG ; 2018
    In:  Cancers Vol. 10, No. 3 ( 2018-03-05), p. 65-
    Details
    In: Cancers, MDPI AG, Vol. 10, No. 3 ( 2018-03-05), p. 65-
    Abstract: Background: The aim of this study was to validate a new definition of borderline resectable pancreatic ductal adenocarcinoma (PDAC) provided by the 2017 international consensus on the basis of three dimensions of anatomical (A), biological (B), and conditional (C) factors, using the data of the patients who had been registered for our institutional protocol of chemoradiotherapy followed by surgery (CRTS) for localized patients with PDAC. Methods: Among 307 consecutive patients pathologically diagnosed with localized PDAC who were enrolled in our CRTS protocol from February 2005 to December 2016, we selected 285 patients who could be re-evaluated after CRT. These 285 patients were classified according to international consensus A definitions as follows: R (resectable; n = 62), BR-PV (borderline resectable, superior mesenteric vein (SMV)/portal vein (PV) involvement alone; n = 27), BR-A (borderline resectable, arterial involvement; n = 50), LA (locally advanced; n = 146). Disease-specific survival (DSS) was analyzed according to A, B (serum CA 19-9 levels and lymph node metastasis diagnosed by computed tomography findings before CRT), and C factors (performance status (PS)) factors. Results: The rates of resection and R0 resection were similar between R (83.9 and 98.0%) and BR-PV (85.2 and 95.5%), but much lower in BR-A (70.0 and 84.8%) and LA (46.6 and 62.5%). DSS evaluated by median survival time (months) showed a similar trend to surgical outcomes: 33.7 in R, 27.3 in BR-PV, 18.9 in BR-A and 19.3 in LA, respectively. DSS in R patients with CA 19-9 levels 〉 500 U/mL was significantly poorer than in patients with CA 19-9 levels ≤ 500 U/mL, but there were no differences in DSS among BR-PV, BR-A, and LA patients according to CA 19-9 levels. Regarding lymph node metastasis, there was no significant difference in DSS according to each resectability group. DSS in R patients with PS ≥ 2 was significantly worse than in patients with PS 0-1. Conclusions: The international consensus on the definition of BR-PDAC based on three dimensions of A, B, and C is useful and practicable because prognosis of PDAC patients is influenced by anatomical factors as well as biological and conditional factors, which in turn may help to decide treatment strategy.
    Type of Medium: Online Resource
    ISSN: 2072-6694
    URL: Article
    DOI: 10.3390/cancers10030065
    Language: English
    Publisher: MDPI AG
    Publication Date: 2018
    detail.hit.zdb_id: 2527080-1
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