Understanding paleo-earthquakes in the Kuril Trench based on Late-Holocene tsunami deposits in the distal region from wave sources, northern Hidaka, Hokkaido, Japan.

Geological evidence, such as tsunami deposits, is crucial for studying the largest rupture zone of the Kuril Trench in Hokkaido, Japan, due to its poor historical record. Although 17th-century tsunami deposits are widely distributed across Hokkaido, the presence of multiple wave sources during that period, including the collapse of Mt. Komagatake, complicates the correlation with their wave sources. Understanding the regional distribution of these tsunami deposits can provide valuable data to estimate the magnitude of megathrust earthquakes in the Kuril Trench. The northern part of Hidaka, Hokkaido, where tsunamis from multiple wave sources are expected to overlap, is distant from the Kuril Trench. To clarify the depositional history of tsunami deposits in such distal areas, evaluating the influence of the depositional environments on the event layer preservation becomes even more critical. We conducted field surveys in Kabari, located in the northern Hidaka region, identifying three sand layers from the 10th to the 17th century and two layers dating beyond 2.3 thousand years ago. The depositional ages of most sand layers potentially correlate with tsunami deposits resulting from the Kuril Trench earthquakes. Utilizing reconstructed paleo-sea level data, we estimated that most sand layers reached approximately 2 m in height. However, it is noteworthy that the latest sand layer from the 17th century exhibited an unusual distribution, more than 3 m in height. This suggests a different wave source as the Mt. Komagatake collapse. The discovery of multiple sand layers and their distributions is crucial to constraining the maximum magnitude of giant earthquakes in the Kuril Trench and understanding the volcanic tsunami events related to Mt. Komagatake.

Groundwater dynamics on small carbonate islands: Insights from radiocarbon and stable isotopes in Kikai Island, Southwest Japan.

Groundwater, the world's largest freshwater resource, faces significant challenges due to the overexploitation and depletion of aquifers in the 21st century. Small island groundwater aquifers are particularly valuable, and a scientific understanding of the behavior of subsurface water systems is vital. A comprehensive study using radiocarbon, stable oxygen isotopes, stable hydrogen isotopes, and hardness analysis (Δ14C, δ18O, δD, Ca, Mg) of groundwater was conducted in Kikai Island, a southern island in the Amami archipelago, Japan. The geological features and small size of the island make it an ideal location for assessing groundwater recharge and discharge relationships. Groundwater dynamics were investigated using samples collected seasonally from 15 points around the island (wells, springs, and an underground dam). Δ14C results indicated that despite considerable differences in precipitation, spatial variations were more prominent than seasonal variations, suggesting the presence of a large groundwater reservoir. The stable isotopes and hardness values, commonly used to detect groundwater dynamics, did not provide clear evidence to support this trend for the study site, a low-lying small island. However, the combination of deuterium excess (d-excess) values with radiocarbon analysis has the potential to provide a better understanding of groundwater flow. This study further illustrates that a combined approach utilizing Δ14C, δ18O, δD, and hardness levels can yield invaluable insights into groundwater dynamics. Considering geomorphic and geological features, groundwater in Kikai Island was categorized into five groups, providing insights into spatial groundwater flow. Results of this study indicate that the use of 14C allows the detection of groundwater movement with a high dynamic range and increased sensitivity, deepening our understanding of the diverse carbon sources that influence the groundwater system. Insights from this study are especially important for the efficient water management in comparable small carbonate islands and for tackling issues associated to overexploitation, pollution, and water scarcity.

Subtyping of Group 3/4 medulloblastoma as a potential prognostic biomarker among patients treated with reduced dose of craniospinal irradiation: a Japanese Pediatric Molecular Neuro-Oncology Group study.

BACKGROUND: One of the most significant challenges in patients with medulloblastoma is reducing the dose of craniospinal irradiation (CSI) to minimize neurological sequelae in survivors. Molecular characterization of patients receiving lower than standard dose of CSI therapy is important to facilitate further reduction of treatment burden. METHODS: We conducted DNA methylation analysis using an Illumina Methylation EPIC array to investigate molecular prognostic markers in 38 patients with medulloblastoma who were registered in the Japan Pediatric Molecular Neuro-Oncology Group and treated with reduced-dose CSI. RESULTS: Among the patients, 23 were classified as having a standard-risk and 15 as high-risk according to the classic classification based on tumor resection rate and presence of metastasis, respectively. The median follow-up period was 71.5 months (12.0-231.0). The median CSI dose was 18 Gy (15.0-24.0) in both groups, and 5 patients in the high-risk group received a CSI dose of 18.0 Gy. Molecular subgrouping revealed that the standard-risk cohort included 5 WNT, 2 SHH, and 16 Group 3/4 cases; all 15 patients in the high-risk cohort had Group 3/4 medulloblastoma. Among the patients with Group 3/4 medulloblastoma, 9 of the 31 Group 3/4 cases were subclassified as subclass II, III, and V, which were known to an association with poor prognosis according to the novel subtyping among the subgroups. Patients with poor prognostic subtype showed worse prognosis than that of others (5-year progression survival rate 90.4% vs. 22.2%; p < 0.0001). The result was replicated in the multivariate analysis (hazard ratio12.77, 95% confidence interval for hazard ratio 2.38-99.21, p value 0.0026 for progression-free survival, hazard ratio 5.02, 95% confidence interval for hazard ratio 1.03-29.11, p value 0.044 for overall survival). CONCLUSION: Although these findings require validation in a larger cohort, the present findings suggest that novel subtyping of Group 3/4 medulloblastoma may be a promising prognostic biomarker even among patients treated with lower-dose CSI than standard treatment.

Incidence of Cerebral Cavernous Malformation-Related Epilepsy in Children: A Single Center Survey.

INTRODUCTION: Cerebral cavernous malformations (CCMs) are rare developmental cerebrovascular malformations. The risk of epilepsy is high in patients with CCMs, but the incidence of epilepsy has not been reported in a pure pediatric population. We herein present 14 pediatric cases of CCMs, including five with CCM-related epilepsy, and examine the incidence of CCM-related epilepsy in this pediatric population.  Methods: Pediatric patients with CCMs who visited our Hospital between November 1, 2001, to September 31, 2020, were retrospectively screened for inclusion, and 14 were enrolled.  Results: Fourteen enrolled patients were divided into two groups based on the presence or absence of CCM-related epilepsy. The "CCM-related epilepsy group" (n = 5) consisted of five males with a median age of 4.2 (range: 0.3-8.5) years at the first visit. The "non-epilepsy group" (n = 9) consisted of seven males and two females with a median age of 3.5 (range: 1.3-11.5) years at the first visit. The prevalence of CCM-related epilepsy at the time of the present analysis was 35.7%. Follow-up periods in CCM-related epilepsy and non-epilepsy groups were 19.3 and 24.9 patient-years, respectively: the incidence was 11.3% per patient-years. The frequency of seizures due to intra-CCM hemorrhage as the primary symptom was significantly higher in the CCM-related epilepsy group than in the non-CCM-related epilepsy group (p = 0.01). Other clinical characteristics, i.e., primary symptoms including vomiting/nausea and spastic paralysis, magnetic resonance imaging findings, including the number or maximum diameter of CCMs, cortical involvement, intra-CCM hemorrhage, and infratentorial lesions, surgical resection, and non-epileptic sequelae, such as motor disability and intellectual disability, did not significantly differ between the groups.  Discussion: The incidence of CCM-related epilepsy in the present study was 11.3% per patient year, higher than in adults. This discrepancy may be attributed to these studies including both adult and pediatric patients, whereas the present study examined a pure pediatric population. The presence of seizures due to intra-CCM hemorrhage as the initial symptom was a risk factor for CCM-related epilepsy in the present study. To elucidate the pathophysiology of CCM-related epilepsy or the reason for its higher incidence in children than in adults, further analyses of a large number of children with CCM-related epilepsy are warranted.

Dataset for the establishment of an age model of marine sediment core KH19-6 Leg.4 PC10/MC14 collected from the Agulhas Ridge in the South Atlantic Ocean.

A precise age model of marine sediment core is crucial for environmental studies of the past such as paleoceanography, paleoclimatology, and paleo-hazard studies. Here the geochemical dataset is described that is used to determine the age model of marine sediment cores collected from Agulhas Ridge in the South Atlantic Ocean using piston coring and multiple-coring systems during the 30th Anniversary expeditions of R/V Hakuho Maru in 2019-2020 (KH19-6 Leg.4 PC10/MC14, water depth of 4,604 m). The top 3.27 meter of 12.28-meter-long piston core (PC10) and a whole 0.29-m-long multiple core (MC14) were dated. The dataset includes radiocarbon ages of planktonic foraminifera shells and oxygen isotopes of both planktonic (Globigerinoides bulloides, Globorotalia inflata) and benthic (Gyroidina soldanii) foraminifera shells. The top 7.5 kyr record was lost, the ages of 3.27 m depth below sea floor was ∼140 kyr ago, and sedimentation rates were 0.9-5.5 kyr/cm.

A case of recurrent refractory cervical primary histiocytic sarcoma treated with pembrolizumab.

Histiocytic sarcoma (HS) is a rare disease with a poor prognosis. The efficacy of immune checkpoint inhibitors for this disease has not been established. A 13-year-old boy with HS refractory to conventional chemotherapy was treated with pembrolizumab, an immune checkpoint inhibitor. After treatment, the primary lesion and the bone metastases showed improvement; however, new metastatic lesions also occurred. This case suggests that the effect of immune checkpoint inhibitors might depend not only on programmed death ligand-1 expression and the ratio of tumor mutational burden, but also on other factors, such as the tumor microenvironment. Evaluation of more cases is required to identify biomarkers that define the efficacy of immune checkpoint inhibitors.

Natal origin of Pacific bluefin tuna Thunnus orientalis determined by SIMS oxygen isotope analysis of otoliths.

Accurate understanding of changing population dynamics associated with climate change is critical for managing highly migratory fish species. However, long-term data on population dynamics and the resulting recruitment variability is still lacking for many species, making it difficult to predict and integrate the effects of ocean warming into management schemes. In this study, high-resolution stable oxygen isotope (δ18O) analysis was performed on the otoliths of adult Pacific bluefin tuna Thunnus orientalis using secondary ion mass spectrometry (SIMS) to determine the natal origin of an individual fish. The core δ18Ootolith corresponding to the larval stage greatly varied among the individuals, indicating that the larvae experienced a wide range of thermal environments. The non-hierarchical cluster analysis performed on the core δ18Ootolith grouped fish into those with higher δ18Ootolith (lower temperature) and those with lower δ18Ootolith (higher temperature), most likely representing relative temperature difference experienced between fish born in the Sea of Japan and in the Nansei Islands area. The Nansei Islands area cluster showed more variability in the early otolith growth indicating a longer spawning season, which is consistent with the observed longer spawning duration in this area. The absolute temperature estimates based on the SIMS-measured core δ18Ootolith were significantly higher than those expected from sea surface temperature data, suggesting the effects of matrix-related bias on the temperature offsets. The relative temperature difference, however, matched well with the known spawning temperature range of the two spawning grounds. The recruitment contribution from each spawning ground (all year-classes pooled, n = 51) was 45% in the Sea of Japan and 55% in the Nansei Islands area. Overall, this study demonstrated the effectiveness of SIMS δ18Ootolith analysis for investigating the natal origin of fish and its potential application in fish population dynamics studies.

Plutonium isotopes in the North Western Pacific sediments coupled with radiocarbon in corals recording precise timing of the Anthropocene.

Plutonium (Pu) has been used as a mid-twentieth century time-marker in various geological archives as a result of atmospheric nuclear tests mainly conducted in 1950s. Advancement of analytical techniques allows us to measure 239Pu and 240Pu more accurately and can thereby reconstruct the Pacific Pu signal that originated from the former Pacific Proving Grounds (PPG) in the Marshall Islands. Here, we propose a novel method that couples annual banded reef building corals and nearshore anoxic marine sediments to provide a marker to precisely determine the start of the nuclear era which is known as a part of the Anthropocene. We demonstrate the efficacy of the methods using sediment obtained from Beppu Bay, Japan, and a coral from Ishigaki Island, Japan. The sedimentary records show a clear Pu increase from 1950, peaking during the 1960s, and then showing a sharp decline during the 1970s. However, a constantly higher isotope ratio between 239Pu and 240Pu suggest an additional contribution other than global fallout via ocean currents. Furthermore, single elevations in 240Pu/239Pu provide supportive evidence of close-in-fallout similar to previous studies. Coral skeletal radiocarbon displays a clear timing with the signatures supporting the reliability of the Beppu Bay sediments as archives and demonstrates the strength of this method to capture potential Anthropocene signatures.

Two-step movement of tsunami boulders unveiled by modified viscous remanent magnetization and radiocarbon dating.

Massive boulders in landslide and tsunami deposits are prominent geomorphic features in various landscapes. Tracking their movement history is important for reconstructing past geologic dynamics; however, the reworking movements of massive boulders remain unresolved. The boulder field on the Ishigaki Island was formed by repeated tsunamis. Although the individual movement histories of boulders contribute to retrodict the history of different magnitude tsunamis, their radiocarbon ages only correspond to the tsunamis that detached boulders from the reef. Viscous remanent magnetization dating methods have been applied in reworking movements. These methods reveal signals associated with remanent magnetization that gradually grew since the reworking event, which helps to determine the passage of time. The methods were verified by comparison to the radiocarbon ages of un-reworked boulders detached by the recent Meiwa tsunami, while the estimated ages of such two boulders based on the classical relaxation theory contradicted the radiocarbon ages. Here, we show that a method based on the stretched exponential function addressed this contradiction. The reworking movement was estimated using an additional boulder, whose, using our method, radiocarbon age indicated that an older tsunami moved it, whereas the remanent magnetization age unveiled a reworking of the boulder attributed to the Meiwa tsunami.

Holocene melting of the West Antarctic Ice Sheet driven by tropical Pacific warming.

The primary Antarctic contribution to modern sea-level rise is glacial discharge from the Amundsen Sea sector of the West Antarctic Ice Sheet. The main processes responsible for ice mass loss include: (1) ocean-driven melting of ice shelves by upwelling of warm water onto the continental shelf; and (2) atmospheric-driven surface melting of glaciers along the Antarctic coast. Understanding the relative influence of these processes on glacial stability is imperative to predicting sea-level rise. Employing a beryllium isotope-based reconstruction of ice-shelf history, we demonstrate that glaciers flowing into the Amundsen Sea Embayment underwent melting and retreat between 9 and 6 thousand years ago. Despite warm ocean water influence, this melting event was mainly forced by atmospheric circulation changes over continental West Antarctica, linked via a Rossby wave train to tropical Pacific Ocean warming. This millennial-scale glacial history may be used to validate contemporary ice-sheet models and improve sea-level projections.

Diagnostic challenges of primary diffuse leptomeningeal melanomatosis in early adolescence: A case report.

INTRODUCTION: Primary diffuse leptomeningeal melanomatosis is an extremely rare variant of primary melanoma of the central nervous system. It is characterized by a variety of nonspecific clinical, radiological, and histopathological features requiring differential diagnosis from a variety of diseases. Here, we aimed to use our own clinical case as an example of the difficulties in the diagnosis of this disease. CASE PRESENTATION: A 14-year-old boy presented with focal to bilateral tonic-clonic seizures. Brain MRI showed diffuse cortical surface and subcortical lesions, isointense on T1-weighted images and hypointense on T2-weighted images, respectively, with diffuse leptomeningeal gadolinium enhancement. Cytology of the cerebrospinal fluid revealed atypical mononuclear cells, but characteristic melanoma cells were not found. Although we suspected meningeal carcinomatosis, we did not perform abrainbiopsy under the tentative diagnosis of Sturge-Weber syndrome. A definitive diagnosis of primary diffuse leptomeningeal melanomatosis was made with abrainbiopsy after hedevelopednon-convulsive status epilepticus. Despite treatment, he died of hydrocephalus 1 year and 8 months after onset. CONCLUSION: Primary diffuse leptomeningeal melanomatosis poses a clinical diagnostic and therapeutic challenge. Leptomeningeal enhancement extending into the cerebral sulci and signal changes in T1/T2 weighted images of cortical and subcortical lesions on MRI are key to an early decision regarding whether to perform a biopsy, even in the pediatric population.

Aggressive growing of the infantile cavernous hemangioma of the calvaria: a case report and review of literature.

INTRODUCTION: Primary intraosseous cavernous hemangiomas of the skull are very rare in the pediatric age group and usually slow-growing tumors. CASE REPORT: We present a case of 5-month-old girl with a left occipital cavernous hemangioma that is rapidly growing. The subcutaneous occipital tiny mass was first noted at birth, and the lesion became rapidly enlarged in size and became soft for 3 months. The left occipital subcutaneous lesion was 4.0 × 4.0 × 2.0 cm (AP × LR × HT) in size. There was no history of trauma or bone tumor in her family. She underwent resection of the lesion, and a pathologic diagnosis of calvarial cavernous hemangioma was made. No recurrence was seen 1 year after surgery. CONCLUSION: The rapid growth of the infant cavernous hemangioma might be related to not only bleeding and/or congestion of the lesion but the immature thin skull of the infant.

ESR and Radiocarbon Dating of Gut Strings from Early Plucked Instruments.

Early European plucked instruments have recently experienced a great revival, but a few aspects remain unknown (e.g., the gauge of gut strings). Here we report, for the first time, that the electron spin resonance (ESR) signal intensity of oxidized iron, Fe(III), from gut strings at g = 2 increases linearly with age within a few hundred years. The signal increase in the remaining old strings on early instruments can be used to judge if they are as old as or younger than the instrument. Obtaining the authenticity information of gut strings contributes to the revival of the old instruments and the music.

A sea-level plateau preceding the Marine Isotope Stage 2 minima revealed by Australian sediments.

Further understanding of past climate requires a robust estimate of global ice volume fluctuations that in turn rely on accurate global sea-level reconstructions. An advantage of Marine Isotope Stage 2 (MIS 2) is the availability of suitable material for radiocarbon dating to allow comparison of sea-level data with other paleoclimatic proxies. However, the number and accuracy of sea-level records during MIS 2 is currently lacking. Here we present the history of MIS 2 eustatic sea-level change as recorded in the Bonaparte Gulf, northwestern Australia by reconstructing relative sea level and then modeling glacial isostatic adjustment. The isostatically-corrected global sea-level history indicates that sea-level plateaued from 25.9 to 20.4 cal kyr BP (modeled median probability) prior reaching its minimum (19.7 to 19.1 cal kyr BP). Following the plateau, we detect a 10-m global sea-level fall over ~1,000 years and a short duration of the Last Glacial Maximum (global sea-level minimum; 19.7 to 19.1 cal kyr BP). These large changes in ice volume over such a short time indicates that the continental ice sheets never reached their isostatic equilibrium during the Last Glacial Maximum.

Insight into anaerobic methanotrophy from 13C/12C- amino acids and 14C/12C-ANME cells in seafloor microbial ecology.

Oceanic methane from global deep-sea sediment is largely consumed through microbially mediated sulfate-coupled oxidation, resulting in 13C-depleted cell biomass of anaerobic methanotrophic archaea (ANME). The general ecological importance of subseafloor ANME has been well recognized in the last two decades. However, the crucial biochemical pathways for the overall anaerobic oxidation of methane (AOM) still remain enigmatic. Here, methanotrophic pathways were analyzed to trace 13C-depleted amino acid biosynthesis in two clades of ANME (ANME-1 and ANME-2) from the Black Sea. Compound-specific analysis of ANME-dominated microbial mats showed a significant 13C-depletion trend in association with increasing carbon numbers in protein-derived amino acid families (e.g., the pyruvate family in the order of alanine, valine, isoleucine and leucine was down to -114‰). This result indicates a stepwise elongation of 13C-depleted carbon during amino acid biosynthesis. The overall results suggest that intracellular protein amino acids and the most 13C-depleted signature of leucine, which has a specific branched-chain structure, are potentially propagated as isoprenoid precursor molecules into archaeal biosynthesis, resulting in the extremely 13C- and 14C-depleted nature of ANME cells in the deep microbial oasis.

Rapid glaciation and a two-step sea level plunge into the Last Glacial Maximum.

The approximately 10,000-year-long Last Glacial Maximum, before the termination of the last ice age, was the coldest period in Earth's recent climate history1. Relative to the Holocene epoch, atmospheric carbon dioxide was about 100 parts per million lower and tropical sea surface temperatures were about 3 to 5 degrees Celsius lower2,3. The Last Glacial Maximum began when global mean sea level (GMSL) abruptly dropped by about 40 metres around 31,000 years ago4 and was followed by about 10,000 years of rapid deglaciation into the Holocene1. The masses of the melting polar ice sheets and the change in ocean volume, and hence in GMSL, are primary constraints for climate models constructed to describe the transition between the Last Glacial Maximum and the Holocene, and future changes; but the rate, timing and magnitude of this transition remain uncertain. Here we show that sea level at the shelf edge of the Great Barrier Reef dropped by around 20 metres between 21,900 and 20,500 years ago, to -118 metres relative to the modern level. Our findings are based on recovered and radiometrically dated fossil corals and coralline algae assemblages, and represent relative sea level at the Great Barrier Reef, rather than GMSL. Subsequently, relative sea level rose at a rate of about 3.5 millimetres per year for around 4,000 years. The rise is consistent with the warming previously observed at 19,000 years ago1,5, but we now show that it occurred just after the 20-metre drop in relative sea level and the related increase in global ice volumes. The detailed structure of our record is robust because the Great Barrier Reef is remote from former ice sheets and tectonic activity. Relative sea level can be influenced by Earth's response to regional changes in ice and water loadings and may differ greatly from GMSL. Consequently, we used glacio-isostatic models to derive GMSL, and find that the Last Glacial Maximum culminated 20,500 years ago in a GMSL low of about -125 to -130 metres.

Case report of a 6-year-old girl with Mycoplasma hominis ventriculoperitoneal shunt infection.

Mycoplasma hominis is a rare causative pathogen for surgical site infections after neurosurgical procedures. This organism lacks a cell wall, rendering it undetectable by Gram staining and making it resistant to beta-lactam antibiotics. In addition, some special techniques are required to identify this organism. Thus, it is very difficult to diagnose infections caused by this pathogen. Here, the authors report a pediatric case of M. hominis ventriculoperitoneal shunt (VPS) infection with central nervous system involvement for which beta-lactam antibiotics were not effective and Gram staining revealed no pathogens. Because few cases have been described that involve the treatment of M. hominis infection after neurosurgery, in this case the patient's serum and CSF were monitored for antibiotic drug concentrations. Successful treatment of the infection was achieved after approximately 6 weeks of administration of clindamycin and ciprofloxacin antibiotics in addition to external ventricular drain revision and subsequent VPS replacement. When beta-lactam antibiotics are ineffective and when Gram staining cannot detect the responsible pathogens, it is important to consider M. hominis as the atypical pathogen.