331 research outputs found

    Alteration Reaction and Mass Transfer via Fluids with Progress of Fracturing along the Median Tectonic Line, Mie Prefecture, Southwest Japan

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    We have analyzed mass transfer in the cataclasite samples collected from the Median Tectonic Line, southwest Japan, in which the degree of fracturing is well correlated with the bulk rock chemical compositions determined by the X-ray fluorescence (XRF) analysis. The results of “isocon” analysis indicate not only a large volume increase up to 110% but also the two-stage mass transfer during cataclasis. At the first stage from the very weakly to weakly fractured rocks, the weight percents of SiO2, Na2O, and K2O increase, while those of TiO2, FeO, MnO, MgO, and CaO decrease. At the second stage from the weakly to moderately and strongly fractured rocks, the trend of mass transfer is reversed. The principal component analysis reveals that the variation of chemical compositions in the cataclasite samples can be mostly interpreted by the mass transfer via fluids and by the difference in chemical composition in the protolith rocks to lesser degree. Finally, the changes in the modal composition of minerals with increasing cataclasis analyzed by the X-ray diffraction (XRD) with the aid of “RockJock” software clearly elucidate that the mass transfer of chemical elements was caused by dissolution and precipitation of minerals via fluids in the cataclasite samples

    Development of an autonomous FM-CW ionospheric observation system based on reinforcement learning

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    第150回地球電磁気・地球惑星圏学会(SGEPSS)総会および講演会, 2021年10月31日-11月4

    Genetic association of glutathione peroxidase-1 with coronary artery calcification in type 2 diabetes: a case control study with multi-slice computed tomography

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    <p>Abstract</p> <p>Background</p> <p>Although oxidative stress by accumulation of reactive oxygen species (ROS) in diabetes has become evident, it remains unclear what genes, involved in redox balance, would determine susceptibility for development of atherosclerosis in diabetes. This study evaluated the effect of genetic polymorphism of enzymes producing or responsible for reducing ROS on coronary artery calcification in type 2 diabetes (T2D).</p> <p>Methods</p> <p>An index for coronary-arteriosclerosis, coronary artery calcium score (CACS) was evaluated in 91 T2D patients using a multi-slice computed tomography. Patients were genotyped for ROS-scavenging enzymes, <it>Glutathione peroxidase-1 (GPx-1)</it>, <it>Catalase, Mn-SOD</it>, <it>Cu/Zn-SOD</it>, as well as SNPs of <it>NADPH oxidase </it>as ROS-promoting elements, genes related to onset of T2D (<it>CAPN10, ADRB3, PPAR gamma, FATP4</it>). Age, blood pressure, BMI, HbA<sub>1c</sub>, lipid and duration of diabetes were evaluated for a multivariate regression analysis.</p> <p>Results</p> <p>CACS with Pro/Leu genotype of the <it>GPx-1 </it>gene was significantly higher than in those with Pro/Pro (744 ± 1,291 vs. 245 ± 399, respectively, <it>p </it>= 0.006). In addition, genotype frequency of Pro/Leu in those with CACS ≥ 1000 was significantly higher than in those with CACS < 1000 (45.5% vs. 18.8%; <it>OR </it>= 3.61, <it>CI </it>= 0.97–13.42; <it>p </it>= 0.045) when tested for deviation from Hardy-Weinberg's equilibrium. Multivariate regression analyses revealed that CACS significantly correlated with <it>GPx-1 </it>genotypes and age.</p> <p>Conclusion</p> <p>The presence of Pro197Leu substitution of the <it>GPx-1 </it>gene may play a crucial role in determining genetic susceptibility to coronary-arteriosclerosis in T2D. The mechanism may be associated with a decreased ability to scavenge ROS with the variant <it>GPx-1</it>.</p

    甲状腺癌リンパ節転移との鑑別が困難であった頸部神経鞘腫の1例

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    A female patient in her 60s visited her previous doctor because of a right cervical mass that exist for 7 years and gradually increased in size. As she was suspected of cervical lymph node metastasis of thyroid cancer, she was referred to our hospital. At the initial visit, a 5-cm right cervical mass and enlargement of the right lobe of the thyroid gland were observed. Fine needle aspiration cytology was performed on both, but no malignant findings were observed. To confirm the diagnosis and improve the patient’s appearance, a right lobectomy of the thyroid gland and resection of the right cervical mass were performed. A rapid intraoperative histological examination of the cervical mass revealed a schwannoma. The right thyroid tumor was diagnosed as follicular adenoma. Her postoperative course was good, and after several years of follow-up, patient consultation was terminated. Neurolemmoma is a benign tumor arising from Schwann cells in the nerve sheath, and it occurs frequently throughout the head and neck region, with 25%-45% of cases occurring in this region. Cervical schwannomas are characterized by irritation of the vagus nerve, brachial plexus, and sympathetic nerves. However, many patients present with only a painless neck mass, as in this case. Although the mass can be diagnosed by puncture aspiration cytology in some cases, sufficient specimens are often unavailable, and the diagnosis is made preoperatively in about half of all cases. Differential diagnoses of an anterior cervical mass include malignant lymphoma, cervical lymph node metastases of malignant tumors, submandibular gland tumors, and tuberculous lymph node metastases. In this patient, we also considered lymph node metastasis of thyroid cancer. However, a histological examination did not detect malignancy in either the thyroid gland or neck mass, and we considered that the thyroid follicular adenoma and the cervical schwannoma occurred independently. We report our experience of cervical schwannoma combined with thyroid tumor which was suspected of lymph node metastasis of thyroid cancer

    Impact of pathological tumor stage for salvage radiotherapy after radical prostatectomy in patients with prostate-specific antigen < 1.0 ng/ml

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    <p>Abstract</p> <p>Background</p> <p>To evaluate prognostic factors in salvage radiotherapy (RT) for patients with pre-RT prostate-specific antigen (PSA) < 1.0 ng/ml.</p> <p>Methods</p> <p>Between January 2000 and December 2009, 102 patients underwent salvage RT for biochemical failure after radical prostatectomy (RP). Re-failure of PSA after salvage RT was defined as a serum PSA value of 0.2 ng/ml or more above the postradiotherapy nadir followed by another higher value, a continued rise in serum PSA despite salvage RT, or initiation of systemic therapy after completion of salvage RT. Biochemical relapse-free survival (bRFS) was estimated using the Kaplan-Meier method. Multivariate analysis was performed using the Cox proportional hazards regression model.</p> <p>Results</p> <p>The median follow-up period was 44 months (range, 11-103 months). Forty-three patients experienced PSA re-failure after salvage RT. The 4-year bRFS was 50.9% (95% confidence interval [95% CI]: 39.4-62.5%). In the log-rank test, pT3-4 (p < 0.001) and preoperative PSA (p = 0.037) were selected as significant factors. In multivariate analysis, only pT3-4 was a prognostic factor (hazard ratio: 3.512 [95% CI: 1.535-8.037], p = 0.001). The 4-year bRFS rates for pT1-2 and pT3-4 were 79.2% (95% CI: 66.0-92.3%) and 31.7% (95% CI: 17.0-46.4%), respectively.</p> <p>Conclusions</p> <p>In patients who have received salvage RT after RP with PSA < 1.0 ng/ml, pT stage and preoperative PSA were prognostic factors of bRFS. In particular, pT3-4 had a high risk for biochemical recurrence after salvage RT.</p

    In vivo tracking transplanted cardiomyocytes derived from human induced pluripotent stem cells using nuclear medicine imaging

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    Introduction: Transplantation of human induced pluripotent stem cell-derived cardiomyocytes (iPSC-CMs) is a promising treatment for heart failure. Information on long-term cell engraftment after transplantation is clinically important. However, clinically applicable evaluation methods have not yet been established. Methods: In this study, to noninvasively assess transplanted cell engraftment, human SLC5A5, which encodes a sodium/iodide symporter (NIS) that transports radioactive tracers such as 125I, 18F-tetrafluoroborate (TFB), and 99mTc-pertechnetate (99mTcO4−), was transduced into human induced pluripotent stem cells (iPSCs), and nuclear medicine imaging was used to track engrafted human iPSC-CMs. Results: To evaluate the pluripotency of NIS-expressing human iPSCs, they were subcutaneously transplanted into immunodeficient rats. Teratomas were detected by 99mTcO4− single photon emission computed tomography (SPECT/CT) imaging. NIS expression and the uptake ability of 125I were maintained in purified human iPSC-CMs. NIS-expressing human iPSC-CMs transplanted into immunodeficient rats could be detected over time using 99mTcO4− SPECT/CT imaging. Unexpectedly, NIS expression affected cell proliferation of human iPSCs and iPSC-derived cells. Discussion: Such functionally designed iPSC-CMs have potential clinical applications as a noninvasive method of grafted cell evaluation, but further studies are needed to determine the effects of NIS transduction on cellular characteristics and functions

    Survey of imaging dose in HDR brachytherapy

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    Institutional imaging protocols for the verification of brachytherapy applicator placements were investigated in a survey study of domestic radiotherapy institutions. The survey form designed by a free on-line survey system was distributed via the mailing-list system of the Japanese Society for Radiation Oncology. Survey data of 75 institutions between August 2019 and October 2019 were collected. The imaging modalities used were dependent on resources available to the institutions. The displacement of a brachytherapy applicator results in significant dosimetric impact. It is essential to verify applicator placements using imaging modalities before treatment. Various imaging modalities used in institutions included a computed tomography (CT) scanner, an angiography X-ray system, a multi-purpose X-ray system and a radiotherapy simulator. The median total exposure time in overall treatment sessions was ≤75 s for gynecological and prostate cancers. Some institutions used fluoroscopy to monitor the brachytherapy source movement. Institutional countermeasures for reducing unwanted imaging dose included minimizing the image area, changing the imaging orientation, reducing the imaging frequency and optimizing the imaging conditions. It is worth noting that half of the institutions did not confirm imaging dose regularly. This study reported on the usage of imaging modalities for brachytherapy in Japan. More caution should be applied with interstitial brachytherapy with many catheters that can lead to potentially substantial increments in imaging doses for monitoring the actual brachytherapy source using fluoroscopy. It is necessary to share imaging techniques, standardize imaging protocols and quality assurance/quality control among institutions, and imaging dose guidelines for optimization of imaging doses delivered in radiotherapy should be developed
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