195 research outputs found

    Potential habitat for chum salmon (Oncorhynchus keta) in the Western Arctic based on a bioenergetics model coupled with a three-dimensional lower trophic ecosystem model

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    AbstractChum salmon (Oncorhynchus keta) are predominantly located in the Bering Sea during summer and fall. However, several studies have recently reported a different tendency as follows. Observed densities of chum salmon were higher in the vicinity of the Bering Strait and the Chukchi Sea than the eastern Bering Sea in September 2007, and Japanese chum salmon migrated to northern areas in the Bering Sea during summer 2009. The sea surface temperature (SST) in the Arctic marginal seas has increased since the mid-1960s, and especially since 2000. We speculated that the SST increase directly promoted salmon northing from the Bering Sea to the Western Arctic. In this study, we estimated the potential habitat for chum salmon in the Western Arctic using a bioenergetics model coupled with a three-dimensional lower trophic ecosystem model (3-D NEMURO). “Potential habitat” was defined as “an area where chum salmon could grow (i.e., the growth rate was positive)”. In the bioenergetics model, the growth rate of an individual chum salmon was calculated as a function of water temperature, salinity, and prey density, which were obtained from the 3-D NEMURO model results. To evaluate the habitat responses under a global warming scenario, we used the modeled monthly change of water temperature between 2005 (averaged from 2001 to 2010) and 2095 (averaged from 2091 to 2100) under the IPCC SRES-A1B scenario. Our calculations, following the global warming scenario, suggested that the potential habitat for chum salmon would expand to the north due to the increase in water temperature and prey density. In contrast, south of 71°N during summer, the potential habitat would shrink regionally because the water temperature exceeded the optimal condition

    Diagnosis of the repetitive brain concussion

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    In this paper the effectiveness of the support system which predicts the risk of the repetitive brain concussion is studied biomechanically. In the risk prediction system, the accident that caused the concussion is reconstructed by analyzing the game video via multibody dynamics and the resulting brain injury is calculated in detail by the finite element method. In order to calculate the aggravation of the brain injury by the repeated brain concussion, the following two methods are examined. In the first method, the material properties of the part of the brain damaged by the1st impact are changed in the simulation of the 2nd impact. In the second method, each brain damage caused by the repeated impacts is accumulated. The system was applied to the real-life accidents that occurred during Judo and American football games. As a result of the simulations, the aggravation of the brain damage due to repetitive concussion was determined numerically in terms of the maximum strain of the brain and the brain damage rate of the whole brain. The biomechanical process of the collision accidents and the resulting brain damage were reconstructed based on the video and the results are effective to prevent the future repeated concussion accidents

    Crystalor: Persistent Memory Encryption Mechanism with Optimized Metadata Structure and Fast Crash Recovery

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    This study presents an efficient persistent memory encryption mechanism, named Crystalor, which efficiently realizes a secure persistent/non-volatile memory based on an authentication tree with structural optimization, such as the split counter (SC). Crystalor can completely exploit the advantage of metadata compression techniques, whereas existing mechanisms are incompatible with such optimization. Meanwhile, Crystalor incurs almost no latency overhead under the nominal operation conditions for realizing the crash consistency/recoverability. We implement Crystalor with a state-of-the-art parallelizable authentication tree instance, namely ELM (IEEE TIFS 2022), and evaluate the effectiveness by both algorithmic analyses and system-level simulation in comparison with the existing state-of-the-art ones (e.g., SCUE in HPCA 2023). For protecting a 4 TB memory, Crystalor requires 29–62% fewer clock cycles per memory read/write operation than SCUE owing to the compatibility with the SC. In addition, Crystalor and SCUE require 312GB and 554GB memory overheads for metadata, respectively, which indicates that Crystalor achieves a reduction of memory overhead by 44%. The result of the system-level simulation using the gem5 simulator indicates that Crystalor achieves a reduction of the workload execution time by up to 11.5% from SCUE. Moreover, Crystalor can offer a lazy recovery, which makes recovery several thousand times faster than SCUE

    Electric-Field Modulation of Thermopower for the KTaO3 Field Effect Transistors

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    We show herein fabrication and field-modulated thermopower for KTaO3 single-crystal based field-effect transistors (FETs). The KTaO3 FET exhibits field effect mobility of ~8 cm2/Vs, which is ~4 times larger than that of SrTiO3 FETs. The thermopower of the KTaO3 FET decreased from 600 to 220 microV/K by the application of gate electric field up to 1.5 MV/cm, ~400 microV/K below that of an SrTiO3 FET, clearly reflecting the smaller carrier effective mass of KTaO3.Comment: 13 pages, 4 figure

    TGF-β-dependent reprogramming of amino acid metabolism induces epithelial–mesenchymal transition in non-small cell lung cancers

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    Epithelial–mesenchymal transition (EMT)—a fundamental process in embryogenesis and wound healing—promotes tumor metastasis and resistance to chemotherapy. While studies have identified signaling components and transcriptional factors responsible in the TGF-β-dependent EMT, whether and how intracellular metabolism is integrated with EMT remains to be fully elucidated. Here, we showed that TGF-β induces reprogramming of intracellular amino acid metabolism, which is necessary to promote EMT in non-small cell lung cancer cells. Combined metabolome and transcriptome analysis identified prolyl 4-hydroxylase α3 (P4HA3), an enzyme implicated in cancer metabolism, to be upregulated during TGF-β stimulation. Further, knockdown of P4HA3 diminished TGF-β-dependent changes in amino acids, EMT, and tumor metastasis. Conversely, manipulation of extracellular amino acids induced EMT-like responses without TGF-β stimulation. These results suggest a previously unappreciated requirement for the reprogramming of amino acid metabolism via P4HA3 for TGF-β-dependent EMT and implicate a P4HA3 inhibitor as a potential therapeutic agent for cancer

    Identification of the ultrahigh-risk subgroup in neuroblastoma cases through DNA methylation analysis and its treatment exploiting cancer metabolism

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    神経芽腫の新たな診断法と治療戦略を創出 --がん細胞の生存戦略「がん代謝」を逆用する--. 京都大学プレスリリース. 2022-11-02.Neuroblastomas require novel therapies that are based on the exploitation of their biological mechanism. To address this need, we analyzed the DNA methylation and expression datasets of neuroblastomas, extracted a candidate gene characterizing the aggressive features, and conducted functional studies. Based on the DNA methylation data, we identified a subgroup of neuroblastoma cases with 11q loss of heterozygosity with extremely poor prognosis. PHGDH, a serine metabolism-related gene, was extracted as a candidate with strong expression and characteristic methylation in this subgroup as well as in cases with MYCN amplification. PHGDH inhibition suppressed neuroblastoma cell proliferation in vitro and in vivo, indicating that the inhibition of serine metabolism by PHGDH inhibitors is a therapeutic alternative for neuroblastoma. Inhibiting the arginine metabolism, which is closely related to serine metabolism using arginine deiminase, had a combination effect both in vitro and in vivo, especially on extracellular arginine-dependent neuroblastoma cells with ASS1 deficiency. Expression and metabolome analyses of post-dose cells confirmed the synergistic effects of treatments targeting serine and arginine indicated that xCT inhibitors that inhibit cystine uptake could be candidates for further combinatorial treatment. Our results highlight the rational therapeutic strategy of targeting serine/arginine metabolism for intractable neuroblastoma

    Anatomical liver segmentectomy 2 for combined hepatocellular carcinoma and cholangiocarcinoma with tumor thrombus in segment 2 portal branch

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    <p>Abstract</p> <p>Background</p> <p>Hepatic resection is the only effective treatment for combined hepatocellular carcinoma and cholangiocarcinoma.</p> <p>Case presentation</p> <p>A 52-year-old man was preoperatively diagnosed with hepatocellular carcinoma in segment 2 with tumor thrombus in the segment 2 portal branch. Anatomical liver segmentectomy 2, including separation of the hepatic arteries, portal veins, and bile duct, enabled us to remove the tumor and portal thrombus completely. Modified selective hepatic vascular exclusion, which combines extrahepatic control of the left and middle hepatic veins with occlusion of left hemihepatic inflow, was used to reduce blood loss. A pathological examination revealed combined hepatocellular carcinoma and cholangiocarcinoma with tumor thrombus in the segment 2 portal branch. No postoperative liver failure occurred, and remnant liver function was adequate.</p> <p>Conclusion</p> <p>The separation method of the hepatic arteries, portal veins, and bile duct is safe and feasible for a liver cancer patient with portal vein tumor thrombus. Modified selective hepatic vascular exclusion was useful to control bleeding during liver transection. Anatomical liver segmentectomy 2 using these procedures should be considered for a patient with a liver tumor located at segment 2 arising from a damaged liver.</p

    チャクチ海における成層強度の時空間変動とその要因

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    第6回極域科学シンポジウム分野横断セッション:[IA] 急変する北極気候システム及びその全球的な影響の総合的解明―GRENE北極気候変動研究事業研究成果報告2015―11月19日(木) 国立極地研究所1階交流アトリウ
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