Long-term slow-slip events (SSEs) and low-frequency earthquakes (LFEs) repeatedly occur in the area encompassing the Bungo Channel and Hyuga-nada region in Japan. SSEs are slow earthquake events with ...a duration of months to years, characterized by a type of slip that is considered transitional between the fast rupture of regular earthquakes and stable sliding along a plate interface, and have characteristics sensitive to stress states near the plate interface. In addition, since LFEs are also thought to occur at the plate interface, it would be useful to infer the stress state in this region. This study focuses on the stress-dependent characteristics of the b-values of regular earthquakes, SSEs, and LFEs, as well as the spatio-temporal relationships between b-values and these events in this area, using the Japan Unified high-resolution relocated Catalog for Earthquakes (JUICE). The b-value, which represents the relative proportion of large to small earthquakes, is inversely related to differential stress or effective stress. The b-values are moderate to low (b = 0.6–1.1) in regions with a high incidence of long-term SSEs. This spatial b-value anomaly is attributed to the partial release of accumulated stress in regions with a relatively high differential stress due to SSE activity. Furthermore, the b-value distributions estimated in this study provide constraints on the mechanisms that generate LFEs. On the other hand, the b-values increase and decrease before and during periods of enhanced LFE activity in the Bungo Channel, respectively. The increase and following decrease in b-values are thought to reflect episodes of low and high shear strength along the plate interface, which were caused by the presence of abundant slab-derived fluids under undrained conditions above the plate interface, and decreased pore pressure related to fluid depletion via LFE generation, respectively.
•Stress dependent characteristics of b-values, long-term slow slip events (SSEs) and low-frequency earthquakes (LFEs) are focused in this study.•The b-values were moderate to low in regions with a high incidence of long-term SSEs, implying partial release of the accumulated stress by SSEs.•Spatial and temporal b-value distributions suggest that undrained conditions in the overlying plate play a substantial role in LFEs generation.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Iwo‐yama volcano, part of the Kirishima Volcanic Complex, has recently shown signs of unrest. We conducted a hypocenter relocation of shallow earthquakes and broadband magnetotelluric measurements ...around Iwo‐yama. Three‐dimensional inversion of magnetotelluric data revealed an electrically conductive layer that is interpreted as a hydrothermally altered clay‐dominated unit. Shallow earthquakes occur beneath this layer, suggesting that it controls the location of seismicity. The base of the layer corresponds to the depth of a pressure source identified by a leveling survey. These observations suggest that the supply of high‐temperature fluids has increased over time beneath Iwo‐yama, causing an increase in pore pressure beneath the clay‐rich layer and resulting in tectonic earthquakes and ground inflation. Increased upwelling of fluids through a fracture in the clay‐rich layer may have caused a vigorous liquid‐gas phase transition near the surface, which in turn might have led to the small phreatic eruption on 19 April 2018.
Plain Language Summary
Phreatic eruptions result from the sudden release of pressurized fluid into the air. Imaging the pressurized region is important to predict future phreatic eruptions. We studied Iwo‐yama volcano, Kirishima, Japan, where recent volcanic unrest has led to a small phreatic eruption. By imaging the subsurface electrical resistivity structure using the magnetotelluric technique, we have identified a low‐permeability clay‐rich layer at depths of 200–700 m below the surface. Earthquake hypocenters and one of the sources of surface uplift are located beneath this clay layer, so we conclude that the layer caps deep hydrothermal fluids and allows the buildup of pressure beneath it. If this clay‐rich layer suddenly breaks, or if the fluid supply through the deeper conductor suddenly increases, a larger phreatic eruption could occur in the future. Imaging and monitoring of such clay‐rich layers is important to our understanding of shallow activity beneath volcanoes.
Key Points
We conducted earthquake hypocenter relocations and broadband magnetotelluric measurements
Two electrical conductors are, respectively, interpreted to be an altered clay layer and a fluid pathway
The altered layer acts as a cap structure that controlled shallow seismicity, surface deformation, and a small phreatic eruption at Iwo‐yama
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FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
High-throughput DNA sequencing significantly contributed to diagnosis and prognostication in patients with myelodysplastic syndromes (MDS). We determined the biological and prognostic significance of ...genetic aberrations in MDS. In total, 944 patients with various MDS subtypes were screened for known/putative mutations/deletions in 104 genes using targeted deep sequencing and array-based genomic hybridization. In total, 845/944 patients (89.5%) harbored at least one mutation (median, 3 per patient; range, 0-12). Forty-seven genes were significantly mutated with TET2, SF3B1, ASXL1, SRSF2, DNMT3A, and RUNX1 mutated in >10% of cases. Many mutations were associated with higher risk groups and/or blast elevation. Survival was investigated in 875 patients. By univariate analysis, 25/48 genes (resulting from 47 genes tested significantly plus PRPF8) affected survival (P<0.05). The status of 14 genes combined with conventional factors revealed a novel prognostic model ('Model-1') separating patients into four risk groups ('low', 'intermediate', 'high', 'very high risk') with 3-year survival of 95.2, 69.3, 32.8, and 5.3% (P<0.001). Subsequently, a 'gene-only model' ('Model-2') was constructed based on 14 genes also yielding four significant risk groups (P<0.001). Both models were reproducible in the validation cohort (n=175 patients; P<0.001 each). Thus, large-scale genetic and molecular profiling of multiple target genes is invaluable for subclassification and prognostication in MDS patients.
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DOBA, EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, IZUM, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UILJ, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
The influence of non-spectral interference by carbon matrix on trace elements in ICP-MS was studied by considering the chemical and physical interatomic reactions in plasma. The ICP-index was newly ...proposed as an indicator of carbon matrix effect on each element, where the mean free path, first ionization potential and the number of ionization states of an analyte in argon ICP were taken into consideration as main factors. The ICP-index shows a high correlation with the carbon matrix effect as well as other matrix effects caused by elements such as K, and Mg. The ICP-index is a useful criterion for selecting appropriate internal standard elements in quantitative analysis. Taking the ICP-index of each element and the matrix element into consideration, ICP-MS determination can be carried out more accurately.
Neon was applied as a collision gas in a collision/reaction cell of ICP-QMS, since it has a very high ionization potential and does not react with other elements in a collision/reaction cell as well ...as He. Neon was more effective as a collision gas than He even under the same conditions which had been optimized for He and much more effective under the optimum conditions for each collision gas, because the Ne atom is larger and heavier than the He atom. To evaluate the usefulness of Ne as a collision gas, it was applied to the determination of metallic elements in a river water CRM. The results obtained were in good agreement with its certified values. We also proposed a "cell gas index" which assesses the effectiveness of He, H
2
, Ne, Ar, O
2
, N
2
, Kr, and Xe as a collision/reaction gas considering their chemical and physical parameters.
A "cell gas index" which assesses the effectiveness of He, H
2
, Ne, Ar, O
2
, N
2
, Kr, and Xe as a collision/reaction gas considering their chemical and physical parameters is proposed.
Mutations in isocitrate dehydrogenase 1/2 (IDH1/2(MT)) are drivers of a variety of myeloid neoplasms. As they yield the same oncometabolite, D-2-hydroxyglutarate, they are often treated as ...equivalent, and pooled. We studied the validity of this approach and found IDH1/2 mutations in 179 of 2119 myeloid neoplasms (8%). Cross-sectionally, the frequencies of these mutations increased from lower- to higher risk disease, thus suggesting a role in clinical progression. Variant allelic frequencies indicated that IDH1(MT) and IDH2(MT) are ancestral in up to 14/74 (19%) vs 34/99 (34%; P=0.027) of cases, respectively, illustrating the pathogenic role of these lesions in myeloid neoplasms. IDH1/2(MT) was associated with poor overall survival, particularly in lower risk myelodysplastic syndromes. Ancestral IDH1(MT) cases were associated with a worse prognosis than subclonal IDH1(MT) cases, whereas the position of IDH2(MT) within clonal hierarchy did not impact survival. This may relate to distinct mutational spectra with more DNMT3A and NPM1 mutations associated with IDH1(MT) cases, and more ASXL1, SRSF2, RUNX1, STAG2 mutations associated with IDH2(MT) cases. Our data demonstrate important clinical and biological differences between IDH1(MT) and IDH2(MT) myeloid neoplasms. These mutations should be considered separately as their differences could have implications for diagnosis, prognosis and treatment with IDH1/2(MT) inhibitors of IDH1/2(MT) patients.
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DOBA, EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, IZUM, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UILJ, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
In the treatment of childhood acute lymphoblastic leukemia (ALL), excess shortening of maintenance therapy resulted in high relapse rate, as shown by our previous trial, TCCSG L92-13, in which ...maintenance therapy was terminated at 1 year from initiation of treatment. In this study, we aimed to confirm the long-term outcome of L92-13, and to identify who can or cannot be cured by shorter duration of maintenance therapy. To obtain sentinel cytogenetics information that had been missed before, we performed genetic analysis with genomic microarray and target intron-capture sequencing from diagnostic bone marrow smear. Disease-free survival (DFS) at 10 years from the end of therapy was 66.0±2.8%. Females (n=138) had better DFS (74.6±3.7%) than males (n=142, 57.5±4.2%, P=0.002). Patients with TCF3-PBX1 (n=11) and ETV6-RUNX1 (n=16) had excellent DFS (90.9±8.7% and 93.8±6.1%, respectively), whereas high hyperdiploidy (n=23) was the most unfavorable subgroup, with 56.6±10.3% of DFS. Short duration of therapy can cure more than half of pediatric ALL, especially females, TCF3-PBX1 and ETV6-RUNX1. Our retrospective observations suggest a gender/karyotype inhomogeneity on the impact of brief therapy.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
To clarify the cooperative roles of recurrently identified mutations and to establish a more precise risk classification system in acute myeloid leukemia (AML), we comprehensively analyzed mutations ...in 51 genes, as well as cytogenetics and 11 chimeric transcripts, in 197 adult patients with de novo AML who were registered in the Japan Adult Leukemia Study Group AML201 study. We identified a total of 505 mutations in 44 genes, while only five genes, FLT3, NPM1, CEBPA, DNMT3A and KIT, were mutated in more than 10% of the patients. Although several cooperative and exclusive mutation patterns were observed, the accumulated mutation number was higher in cytogenetically normal AML and lower in AML with RUNX1-RUNX1T1 and CBFB-MYH11, indicating a strong potential of these translocations for the initiation of AML. Furthermore, we evaluated the prognostic impacts of each sole mutation and the combinations of mutations and/or cytogenetics, and demonstrated that AML patients could be clearly stratified into five risk groups for overall survival by including the mutation status of DNMT3A, MLL-PTD and TP53 genes in the risk classification system of the European LeukemiaNet. These results indicate that the prognosis of AML could be stratified by the major mutation status in combination with cytogenetics.
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DOBA, EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, IZUM, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UILJ, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
A universal isotope dilution analysis method, which is applicable for the determination of monoisotopic elements as well as multiple stable isotopes was used. The universal isotope dilution analysis ...for As was demonstrated using a mixture of CH
4
and CD
4
gases as the reaction gas in ICP-MS. When As ions react with the CH
4
gas in the ICP-MS reaction cell, As
+
CH
2
molecular ions are selectively produced. Therefore, a mixture of CH
4
and CD
4
gases is introduced into a reaction cell to generate As
+
CH
2
(
m
/
z
89) and As
+
CD
2
(
m
/
z
91), and the signal intensity ratios of
m
/
z
89 and 91 are measured with and without a third element (
89
Y
+
or
91
Zr
+
). The As concentration is calculated from the intensity ratios and the mass abundances of CH
4
, CD
4
, and the third element (
89
Y or
91
Zr). The universal isotope dilution analysis was applied to the determination of As in certified reference materials, and the As concentrations determined were consistent with the certified values.
Universal ID method using a labelled reaction gas in ICP-DRC-MS was investigated and was developed for arsenic determination.
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