163 results on '"Koji Yazawa"'
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2. Structure of alumina glass
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Hideki Hashimoto, Yohei Onodera, Shuta Tahara, Shinji Kohara, Koji Yazawa, Hiroyo Segawa, Motohiko Murakami, and Koji Ohara
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Medicine ,Science - Abstract
Abstract The fabrication of novel oxide glass is a challenging topic in glass science. Alumina (Al2O3) glass cannot be fabricated by a conventional melt–quenching method, since Al2O3 is not a glass former. We found that amorphous Al2O3 synthesized by the electrochemical anodization of aluminum metal shows a glass transition. The neutron diffraction pattern of the glass exhibits an extremely sharp diffraction peak owing to the significantly dense packing of oxygen atoms. Structural modeling based on X-ray/neutron diffraction and NMR data suggests that the average Al–O coordination number is 4.66 and confirms the formation of OAl3 triclusters associated with the large contribution of edge-sharing Al–O polyhedra. The formation of edge-sharing AlO5 and AlO6 polyhedra is completely outside of the corner-sharing tetrahedra motif in Zachariasen’s conventional glass formation concept. We show that the electrochemical anodization method leads to a new path for fabricating novel single-component oxide glasses.
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- 2022
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3. Effects of anion incorporation on the local structure of porous-type amorphous alumina prepared by anodization: NMR study of Al coordination numbers
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Hideki Hashimoto, Yuki Fujita, Koji Yazawa, and Hidetaka Asoh
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Amorphous alumina ,Anodic porous alumina ,Anion incorporation ,Solid-state NMR ,Coordination number ,Physics ,QC1-999 - Abstract
Although anodization is an essential technology that has supported the aluminum industry for nearly a century, the atomistic structure of the formed alumina films has not completely understood. Here we used NMR spectroscopy to clarify the factors affecting local structure of anodic porous alumina films prepared under various electrolytic conditions. For anion-free amorphous alumina films prepared using chromic acid, the local structure does not depend on electrolytic factors. For films prepared using phosphoric acid, the average coordination number was lower than that of anion-free alumina. On the other hand, films prepared using oxalic and sulfuric acids showed the average coordination numbers higher than that of anion-free alumina. We reveal that aluminum coordination number of anodic porous alumina are affected by anion species and anion content. In addition, the depth of anion incorporation into cell walls, or compositional uniformity, is quite important for accurate interpretation of NMR spectra.
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- 2023
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4. Congenital perineal urethrocutaneous fistula without rupture in a neonate
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Fumi Matsumoto, Satoko Matsuyama, Futoshi Matsui, and Koji Yazawa
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Urethrocutaneous fistula ,Congenital ,Perineum ,Urethral diverticulum ,Diseases of the genitourinary system. Urology ,RC870-923 - Abstract
Congenital anterior urethrocutaneous fistula (CAUF) is a rare anomaly, commonly observed in the mid-shaft or more distal position of the penis. It can be seen in the perineum in anorectal anomalies or in cases of duplicated urethra. However, isolated CAUF opening into the perineum has not been reported. Herein, we present a case of congenital anterior urethral diverticulum and possible perineal urethrocutaneous fistula of an otherwise healthy neonate.
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- 2021
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5. Negative dielectric constant of water confined in nanosheets
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Akira Sugahara, Yasunobu Ando, Satoshi Kajiyama, Koji Yazawa, Kazuma Gotoh, Minoru Otani, Masashi Okubo, and Atsuo Yamada
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Science - Abstract
Confinement within nanospace could significantly alter the properties of chemical species. Here the authors report the negative dielectric constant of water confined in nanosheets that can enhance the capacitance of electric-double layer capacitor electrodes.
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- 2019
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6. Transplantation of Allogenic Fetal Membrane-Derived Mesenchymal Stem Cells Protects against Ischemia/Reperfusion-Induced Acute Kidney Injury
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Hidetoshi Tsuda, Kenichi Yamahara, Kentaro Otani, Masayoshi Okumi, Koji Yazawa, Jun-Ya Kaimori, Akihiko Taguchi, Kenji Kangawa, Tomoaki Ikeda, Shiro Takahara, and Yoshitaka Isaka M.D., Ph.D.
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Medicine - Abstract
Mesenchymal stem cells (MSCs) are an attractive therapeutic cell source for treating renal diseases. MSC administration has been shown to improve renal function, although the underlying mechanisms are not completely understood. We recently showed that allogenic fetal membrane-derived MSCs (FM-MSCs), which are available noninvasively in large amounts, had a renoprotective effect in an experimental glomerulonephritis model. Here we investigated whether allogenic FM-MSC administration could protect kidneys from ischemia/ reperfusion (I/R) injury. Lewis rats were subjected to right nephrectomy and left renal I/R injury by clamping the left renal artery as an acute kidney injury (AKI) model. After declamping, FM-MSCs (5 × 10 5 cells) obtained from major histocompatibility complex (MHC)-mismatched ACI rats were intravenously administered. I/R-injured rats exhibited increased serum creatinine and BUN, whereas FM-MSC administration significantly ameliorated renal function. Histological analysis revealed that FM-MSC administration significantly suppressed tubular apoptosis and infiltration of macrophages and T-cells. Administration of FM-MSCs mainly homed into the lung, but increased serum IL-10 levels. Of interest is that renoprotective effects of FM-MSCs were abolished by using anti-IL-10 neutralization antibody, suggesting that IL-10 would be one of the candidate factors to protect rat kidney from I/R injury in this model. We concluded that allogenic FM-MSC transplantation is a potent therapeutic strategy for the treatment of AKI.
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- 2014
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7. Non-invasive magnetic resonance imaging in rats for prediction of the fate of grafted kidneys from cardiac death donors.
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Jun-Ya Kaimori, Satomi Iwai, Masaki Hatanaka, Takumi Teratani, Yoshitsugu Obi, Hidetoshi Tsuda, Yoshitaka Isaka, Takashi Yokawa, Kagayaki Kuroda, Naotsugu Ichimaru, Masayoshi Okumi, Koji Yazawa, Hiromi Rakugi, Norio Nonomura, Shiro Takahara, and Eiji Kobayashi
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Medicine ,Science - Abstract
The main objective of this study was to assess cardiac death (CD) kidney grafts before transplantation to determine whether blood oxygen level-dependent (BOLD) and diffusion MRI techniques can predict damage to these grafts after transplantation. We assessed CD kidney tissue by BOLD and diffusion MRI. We also examined pathological and gene expression changes in CD kidney grafts before and after transplantation. Although there was significantly more red cell congestion (RCC) in the inner stripe of the outer medulla (IS) in both 1 h after cardiac death (CD1h) and CD2h kidneys destined for grafts before transplantation compared with CD0h (p
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- 2013
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8. Carbamylated Erythropoietin Ameliorates Cyclosporine Nephropathy without Stimulating Erythropoiesis
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Toyofumi Abe, Yoshitaka Isaka M.D., Ph.D., Ryoichi Imamura, Yoichi Kakuta, Masayoshi Okumi, Koji Yazawa, Naotsugu Ichimaru, Hidetoshi Tsuda, Norio Nonomura, Shiro Takahara, and Akihiko Okuyama
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Medicine - Abstract
The introduction of cyclosporine (CsA) has improved graft survival, but it causes nephropathy, which limits its clinical utility. Recently, we reported that carbamylated erythropoietin (CEPO) protected kidneys from ischemia reperfusion injury as well as EPO. To investigate the clinical applications of CEPO, we next evaluated the long-term therapeutic effect of CEPO using a CsA-induced nephropathy model. CsA caused renal dysfunction, while EPO/CEPO administration significantly improved renal function. EPO treatment significantly increased Hb concentration, while CEPO treatment neither enhanced nor reduced Hb concentration. CsA treatment induced tubular apoptosis, while EPO/CEPO administration inhibited it and increased PI3 kinase activation and Akt phosphorylation. In parallel, morphological assessment revealed that EPO/CEPO significantly reduced CsA-induced interstitial fibrosis and inhibited interstitial macrophage infiltration. In addition, real-time RT-PCR demonstrated that cortical mRNA levels of TGF-β1 and type I collagen were suppressed in the EPO/CEPO group. These results suggest a new therapeutic approach using CEPO to protect kidneys from CsA-induced nephropathy.
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- 2012
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9. Prenatally Detected Intrascrotal Testicular Teratoma in an Infant
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Makoto Ishii, Fumi Matsumoto, Shinta Suenaga, Futoshi Matsui, and Koji Yazawa
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Urology - Published
- 2023
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10. 1H T1ρ based ROSY: NMR spectral fingerprints for nanoscale phase separated structure of block copolymers
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Koji Yazawa, Naoki Asakawa, and Yusuke Nishiyama
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General Chemical Engineering ,Materials Chemistry ,General Chemistry ,Biochemistry ,Industrial and Manufacturing Engineering - Published
- 2022
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11. Supplementary Table 1 from Orally Active Vitamin D for Potential Chemoprevention of Posttransplant Malignancy
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Yoshitaka Isaka, Shiro Takahara, Hiromi Rakugi, Norio Nonomura, Yoshiharu Tsubakihara, Yukito Kokado, Koji Yazawa, Jun-ya Kaimori, Masayoshi Okumi, Naohiko Fujii, Isao Matsui, Kodo Tomida, Takayuki Hamano, Naotsugu Ichimaru, and Yoshitsugu Obi
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PDF file - 137K, Comparison of baseline characteristics between AVD users and non-users within the tertiles of propensity scores
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- 2023
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12. Data from Orally Active Vitamin D for Potential Chemoprevention of Posttransplant Malignancy
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Yoshitaka Isaka, Shiro Takahara, Hiromi Rakugi, Norio Nonomura, Yoshiharu Tsubakihara, Yukito Kokado, Koji Yazawa, Jun-ya Kaimori, Masayoshi Okumi, Naohiko Fujii, Isao Matsui, Kodo Tomida, Takayuki Hamano, Naotsugu Ichimaru, and Yoshitsugu Obi
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Posttransplant malignancy (PTM) is a limiting factor both for patient and allograft survival in kidney transplant recipients (KTRs). We hypothesized that active vitamin D compounds (AVD) could reduce PTM development in KTRs. Ambulatory KTRs in a Japanese prospective cohort were followed from August 2007 to November 2010. The outcome of interest was newly diagnosed PTM. A propensity score (PS) of having received AVDs was estimated using 26 clinically relevant factors. We used the Cox proportional hazards model with stratification by PS tertiles on the assumption that baseline hazard functions differ among tertiles. As sensitivity analyses, we used inverse probability weighting and PS matching. Among 218 participants, the median age was 50 (interquartile range [IQR], 40 to 59) years, 63.3% were male, median time since transplantation was 11.2 (IQR, 5.2 to 17.1) years, and mean estimated GFR was 41.3 (SD, 15.6) mL/min per 1.73 m2. At baseline, 42.2% had been treated with AVDs mainly for glucocorticoid-induced osteoporosis. AVDs used were calcitriol (58.7%) and alfacalcidol (41.3%). During follow-up, PTM developed in 5.4% of 92 AVD users and 8.7% of 126 nonusers. Poor vitamin D status was common in the participants, but the serum 25-hydroxyvitamin D level was not significantly associated with PTM in Cox regression analysis. After stratifying patients by PS tertiles, we found that AVDs were significantly associated with a lower risk of PTM (HR 0.25 [0.07 to 0.82]). Sensitivity analyses yielded similar results. AVDs are potential chemopreventive agents against PTM in KTRs. Cancer Prev Res; 5(10); 1229–35. ©2012 AACR.
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- 2023
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13. CLINICAL AND IMAGING FINDINGS OF ACUTE EPIDIDYMITIS IN CHILDREN
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Shunsuke Inoguchi, Futoshi Matsui, Satoko Matsuyama, Fuki Kondo, Shinta Suenaga, Koji Yazawa, and Fumi Matsumoto
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Urology - Published
- 2022
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14. Clarification of acid site location in MSE-type zeolites by spectroscopic approaches combined with catalytic activity: comparison between UZM-35 and MCM-68
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Hiroto Toyoda, Ryota Osuga, Yong Wang, Sungsik Park, Koji Yazawa, Hermann Gies, Christopher J. Gilbert, Bilge Yilmaz, C. P. Kelkar, and Toshiyuki Yokoi
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General Physics and Astronomy ,Physical and Theoretical Chemistry - Abstract
MSE-type zeolites synthesized by different organic structure-directing agents (OSDAs), UZM-35 and MCM-68, were prepared. The location of Brønsted acid sites derived from the framework Al atoms and acidic properties were investigated based on
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- 2022
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15. Unilateral Fibrous Hyperplasia of the Labium Majus in Pre- and Early Pubertal Girls: A Report on 3 Cases
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Shinta Suenaga, Fumi Matsumoto, Fuki Kondo, Satoko Matsuyama, Futoshi Matsui, and Koji Yazawa
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Pediatrics, Perinatology and Child Health ,Obstetrics and Gynecology ,General Medicine - Published
- 2022
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16. Heat-induced local structural variation in porous-type amorphous alumina prepared by anodization
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Hideki Hashimoto, Yuki Fujita, Koji Yazawa, and Hidetaka Asoh
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General Materials Science ,General Chemistry ,Condensed Matter Physics - Published
- 2023
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17. Modified Li7P3S11 Glass-Ceramic Electrolyte and Its Characterization
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Koji Yazawa, Kazuki Uchida, Futoshi Utsuno, and Takahiro Ohkubo
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Glass-ceramic ,Materials science ,Relaxation (NMR) ,Analytical chemistry ,Conductivity ,Thermal conduction ,law.invention ,Amorphous solid ,Solid-state nuclear magnetic resonance ,law ,Phase (matter) ,visual_art ,visual_art.visual_art_medium ,General Materials Science ,Ceramic - Abstract
Li7P3S11 glass ceramics have high conductivities competitive with liquid electrolytes, making them good candidates as solid-state electrolytes for all-solid-state lithium-ion batteries. However, the metastable nature and performance of Li7P3S11 glass ceramics remain mysterious. Herein, modified Li7P3S11 glass ceramics with compositions of 70Li2S-30P2S5 were prepared via two-step mechanical milling and thermal annealing. Li7P3S11 glass ceramics synthesized using the conventional method (mechanical milling and thermal annealing) were again ball-milled to obtain amorphous 70Li2S-30P2S5 with a peculiar glass structure. Further thermal annealing was carried out to crystallize the glass. The obtained crystalline phase was analogous to the original Li7P3S11 phase, but the conductivity was enhanced by a factor of 1.7. Based on 31P solid-state nuclear magnetic resonance (NMR) spectroscopy, the Li7P3S11 phase contained an additional PS43- unit. A rational deconvolution procedure for the 31P solid-state NMR spectra based on crystalline Li7P3S11 was developed and applied to the samples. The analysis can resolve the additional crystalline PS43- unit in the Li7P3S11 structure. Based on two-dimensional double-quantum 31P NMR spectroscopy, the additional PS43- unit is located adjacent to the P2S74- unit, suggesting that P2S74- is divided into two PS43- units in the Li7P3S11 phase. The flip motion of Li+ was also investigated based on the 7Li spin-lattice relaxation time. The independent activation energy of spin-lattice relaxation with respect to temperature in the Li7P3S11 phase was attributed to a conduction path between the two PS43- units. The findings provide a synthetic route that can be used to develop metastable solid-state electrolytes.
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- 2021
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18. Bladder Cancer in a Long-term Survivor of the Prune Belly Syndrome
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Fuki Kondo, Fumi Matsumoto, Shinta Suenaga, Futoshi Matsui, Koji Yazawa, Akira Nagahara, Kazuo Nishimura, and Yu Ishizuya
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Urology - Published
- 2022
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19. MITOCHONDRIAL RESPIRATORY CHAIN DISORDERS WITH VESICOURETERAL REFLUX: A PEDIATRIC CASE REPORT.
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Shinta Suenaga, Satoko Matsuyama, Futoshi Matsui, Koji Yazawa, and Fumi Matsumoto
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- 2023
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20. Optically active covalent organic frameworks and hyperbranched polymers with chirality induced by circularly polarized light
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Tamaki Nakano, Koji Yazawa, Yuting Wang, Shuhei Shimoda, Naofumi Naga, Zhiyi Song, Qingyu Wang, Takunori Harada, and Masayoshi Bando
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Materials science ,Hyperbranched polymers ,Metals and Alloys ,02 engineering and technology ,General Chemistry ,Optically active ,Carbon-13 NMR ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,Catalysis ,0104 chemical sciences ,Surfaces, Coatings and Films ,Electronic, Optical and Magnetic Materials ,Crystallography ,Axial chirality ,Covalent bond ,Materials Chemistry ,Ceramics and Composites ,0210 nano-technology ,Chirality (chemistry) ,Linker ,Circular polarization - Abstract
Axial chirality was induced by circularly polarized light to covalent organic frameworks as well as hyperbranched polymers composed of bezene-1,3,5-triyl core units and oligo(benzene-1,4-diyl) as linker units where variation in induction efficiency was rationally interpreted in terms of internal rotation dynamics studied through CPMAS C-13 NMR experiments including CODEX measurements.
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- 2021
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21. Sequential delithiation behavior and structural rearrangement of a nanoscale composite-structured Li1.2Ni0.2Mn0.6O2 during charge–discharge cycles
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Toshiaki Ohta, Eiichiro Matsubara, Takeshi Abe, Koji Yazawa, Keisuke Yamanaka, Zempachi Ogumi, Keiji Shimoda, Toshiyuki Matsunaga, and Miwa Murakami
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Multidisciplinary ,Materials science ,Absorption spectroscopy ,Composite number ,Intercalation (chemistry) ,lcsh:R ,chemistry.chemical_element ,lcsh:Medicine ,02 engineering and technology ,Nuclear magnetic resonance spectroscopy ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,Redox ,0104 chemical sciences ,Ion ,Crystallography ,chemistry ,Phase (matter) ,Lithium ,lcsh:Q ,0210 nano-technology ,lcsh:Science - Abstract
Lithium- and manganese-rich layered oxides (LMRs) are promising positive electrode materials for next-generation rechargeable lithium-ion batteries. Herein, the structural evolution of Li1.2Ni0.2Mn0.6O2 during the initial charge–discharge cycle was examined using synchrotron-radiation X-ray diffraction, X-ray absorption spectroscopy, and nuclear magnetic resonance spectroscopy to elucidate the unique delithiation behavior. The pristine material contained a composite layered structure composed of Ni-free and Ni-doped Li2MnO3 and LiMO2 (M = Ni, Mn) nanoscale domains, and Li ions were sequentially and inhomogeneously extracted from the composite structure. Delithiation from the LiMO2 domain was observed in the potential slope region associated with the Ni2+/Ni4+ redox couple. Li ions were then extracted from the Li2MnO3 domain during the potential plateau and remained mostly in the Ni-doped Li2MnO3 domain at 4.8 V. In addition, structural transformation into a spinel-like phase was partly observed, which is associated with oxygen loss and cation migration within the Li2MnO3 domain. During Li intercalation, cation remigration and mixing resulted in a domainless layered structure with a chemical composition similar to that of LiNi0.25Mn0.75O2. After the structural activation, the Li ions were reversibly extracted from the newly formed domainless structure.
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- 2020
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22. A CASE OF SPLENOGONADAL FUSION PRESENTING NON-PALPABLE TESTIS AND PROXIMAL HYPOSPADIAS
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Koji Yazawa, Satoko Matsuyama, Futoshi Matsui, Fumi Matsumoto, and Akinaru Yamamoto
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Male ,medicine.medical_specialty ,Urology ,Physical examination ,Ilium ,Testis ,Humans ,Medicine ,Abnormalities, Multiple ,Laparoscopy ,Full Term ,Hypospadias ,medicine.diagnostic_test ,business.industry ,Infant ,Anatomy ,Splenogonadal fusion ,medicine.disease ,Left Testis ,Cardiac surgery ,Testis determining factor ,Orchiopexy ,business ,Spleen - Abstract
A 9-month-old boy, having a history of cardiac surgery in neonatal period, was referred to our department for evaluation of genital anomalies. The antenatal course was uneventful, except for unknown gender. His family history was unremarkable. He was delivered at full term, and his birth weight was 3,510 g. Physical examination revealed proximal hypospadias and a non-palpable testis on the left side. Chromosome studies showed a normal male karyotype with positive SRY. At the age of 14 months, he underwent hypospadias repair. Three months later, left testicular exploration was performed along with orchidopexy of an ascending testis on the contralateral side. As nothing was found through an inguinal incision on the left side, laparoscopy was indicated. Laparoscopic observation revealed a small dark reddish mass cranially connected to the left hypoplastic testis that was located high in the left iliac fossa. The epididymis and vas deference looked abnormal, and detachment to the testis was apparent. Testicular vessels were undifferentiated from the mass. Therefore, the left testis was excised with the mass. Histopathological examination confirmed the testis and spleen tissue, and the diagnosis of splenogonadal fusion was made postoperatively.
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- 2020
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23. Variation of Gonadal Dysgenesis and Tumor Risk in Patients With 45,X/46,XY Mosaicism
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Satoko Matsuyama, Keiko Matsuoka, Futoshi Matsui, Fumi Matsumoto, and Koji Yazawa
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Male ,endocrine system ,Pathology ,medicine.medical_specialty ,Gonad ,Adolescent ,Biopsy ,Urology ,030232 urology & nephrology ,Turner Syndrome ,Gonadal dysgenesis ,Gonadoblastoma ,03 medical and health sciences ,Postoperative Complications ,0302 clinical medicine ,Testicular Neoplasms ,Prevalence ,medicine ,Dysgerminoma ,Humans ,In patient ,Castration ,Correlation of Data ,Gonadal Dysgenesis, 46,XY ,Ovarian Neoplasms ,medicine.diagnostic_test ,Mosaicism ,urogenital system ,business.industry ,Infant, Newborn ,45,X/46,XY mosaicism ,Seminoma ,medicine.disease ,medicine.anatomical_structure ,Child, Preschool ,030220 oncology & carcinogenesis ,Female ,Neoplasms, Gonadal Tissue ,Neoplasm Recurrence, Local ,business - Abstract
Objective To describe the gonadal features of patients with 45,X/46,XY mosaicism, and to evaluate the prevalence of gonadal tumor in different phenotypes. Materials and Methods The medical records of consecutive patients with 45,X/46,XY karyotype or its variants who had undergone gonadal biopsy or gonadectomy at a single institute between 1996 and 2017 were retrospectively reviewed. Results Of 34 patients with 45,X/46,XY mosaicism, a unilateral dysgenetic testis and a contralateral streak gonad was detected in 20 patients (59%), bilateral streak gonads in 9 (26%), and bilateral dysgenetic testes in 5 (15%). A gonad composed of both streak and dysgenetic testicular portions was observed in 7 gonads of 6 patients. All streak gonads were removed, and bilateral gonadectomy was performed in 15 patients raised as girls. Pathologic examination revealed gonadal tumors in 6 of the 34 (18%) patients, including a gonadoblastoma in 7 gonads among 5 patients and an association of dysgerminoma with gonadoblastoma in 1 gonad. All 6 patients who developed gonadal tumor had female genitalia. Postoperative course was uneventful except 1 boy. A seminoma was developed in his soritaly scrotal testis at the age of 16 years. Conclusion The prevalence of gonadal tumor in patients with 45,X/46,XY mosaicism may vary according to the phenotype, and high in patients with female phenotype. Considering the increased risk of gonadal tumors in such patients, early investigation and individual management, including prophylactic gonadectomy, are recommended. In male patients, a close follow-up of the preserved testes is mandatory until adulthood.
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- 2020
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24. Realizing the Single-Phase Spinel-Type Sodium Titanium Oxide with the Li4Ti5O12-like Structure for Building Stable Sodium-Ion Batteries
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Riki Kataoka, Koji Yazawa, Toshikatsu Kojima, Kohei Tada, and Mitsunori Kitta
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Materials science ,Sodium ,Spinel ,Oxide ,Sodium-ion battery ,chemistry.chemical_element ,02 engineering and technology ,engineering.material ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,0104 chemical sciences ,Titanium oxide ,chemistry.chemical_compound ,Chemical engineering ,chemistry ,Electrode ,engineering ,General Materials Science ,Single phase ,0210 nano-technology ,Faraday efficiency - Abstract
Sodium titanium oxide with a spinel-type structure is suitable for the stable sodium-intercalation host for the negative electrode of sodium-ion batteries, such as the spinel-type lithium titanium oxide (Li4Ti5O12, LTO) material for lithium-ion batteries. Recently, this has been partly discovered as the Na3LiTi5O12 (NTO) phase in the LTO particle. However, the single-phase NTO material has never been obtained, preventing accurate material characterizations and applications. Here, we successfully realized the NTO material with the single-phase by the chemical sodium insertion-extraction process. The chemical sodium-inserted LTO material is well converted to the pure NTO phase in the single particle level, via following chemical oxidation by water. The purified material was about 97 mol % of NTO as the single-phase spinel structure with a = 8.746 A. The basic lattice framework of the prepared NTO was confirmed to be the same as that of the LTO. The single-phase NTO electrode shows 0.8 V versus Na+/Na of the Na-insertion and extraction potential, and 99.4% of Na-insertion capacity with 99.7% of Coulombic efficiency during 200 cycles of the Na-ion half-cell experiment. Further, the Na2Fe2(SO4)3/NTO full-cell shows 3 V-class stable charge-discharge character during 100 cycles. This excellent stability of Na-insertion and extraction properties of single-phase NTO extends the range of constructing safe and stable high-voltage oxide-based sodium-ion battery cells for practical use.
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- 2020
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25. A case of a preschool child with a successful kidney transplant following the long-term administration of antibiotics to treat peritoneal dialysis-related ESI/peritonitis by Mycobacterium abscessus
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Shinya Nakano, Natsumi Yamamura-Miyazaki, Toshimi Michigami, Koji Yazawa, Itaru Yanagihara, and Katsusuke Yamamoto
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Male ,Mycobacterium abscessus ,Child, Preschool ,Humans ,Infant ,Case Report ,General Medicine ,Peritonitis ,Kidney Transplantation ,Peritoneal Dialysis ,Anti-Bacterial Agents - Abstract
A preschool child with refractory peritoneal dialysis-related exit-site infection (ESI)/peritonitis caused by Mycobacterium abscessus (M. abscessus) received multidrug antibacterial therapy for 6 months and then successfully underwent living-donor kidney transplantation. The patient was a 2.7-year-old boy and the primary disease was bilateral hypo/dysplastic kidneys. Peritoneal dialysis (PD) was initiated at the age of 4 months. Purulent drainage from the PD catheter exit site was observed, and pus and PD effluent cultures were negative. Since living kidney transplantation was scheduled for 2 months later, the PD catheter was replaced. Due to dialysate leakage from the exit site, the new PD catheter was removed and hemodialysis was initiated. M. abscessus subsequently grew from the PD effluent and abscesses that formed at the exit site continued to present bacteria even after catheter removal; therefore, additional debridement was performed. He received combination treatment with antibiotics, amikacin, clarithromycin, imipenem/cilastatin sodium, and tigecycline, for 6 months. After a 4-month observation period without antibiotics, the patient underwent living-donor kidney transplantation. The post-transplantation course was uneventful without the recurrence of infection for 2 years. Although PD-related ESI/peritonitis caused by M. abscessus was intractable, PD catheter removal, multiple debridement, and 6-month antibiotic combination therapy led to improvements. Follow-up observations for 4 months after the cessation of antibacterial treatment confirmed no recurrence of M. abscessus infection, which allowed kidney transplantation. The establishment of an appropriate treatment strategy and observation period for M. abscessus infection ahead of kidney transplantation requires further case accumulation.
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- 2022
26. Effects of Anion Incorporation on the Local Structure of Porous-Type Amorphous Alumina Prepared by Anodization
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Hideki Hashimoto, Yuki Fujita, Koji Yazawa, and Hidetaka Asoh
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History ,Polymers and Plastics ,Business and International Management ,Industrial and Manufacturing Engineering - Published
- 2022
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27. Hysteresis‐Suppressed Reversible Oxygen‐Redox Cathodes for Sodium‐Ion Batteries
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Natalia Voronina, Min‐Young Shin, Hee‐Jae Kim, Najma Yaqoob, Olivier Guillon, Seok Hyun Song, Hyungsub Kim, Hee‐Dae Lim, Hun‐Gi Jung, Younghak Kim, Han‐Koo Lee, Kug‐Seung Lee, Koji Yazawa, Kazuma Gotoh, Payam Kaghazchi, and Seung‐Taek Myung
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ddc:050 ,Renewable Energy, Sustainability and the Environment ,General Materials Science - Abstract
Oxygen-redox-based cathode materials for sodium-ion batteries (SIBs) have attracted considerable attention in recent years owing to the possibility of delivering additional capacity in the high-voltage region. However, they still suffer from not only fast capacity fading but also poor rate capability. Herein, P2-Na0.75[Li0.15Ni0.15Mn0.7]O2 is introduced, an oxygen-redox-based layered oxide cathode material for SIBs. The effect of Ni doping on the electrochemical performance is investigated by comparison with Ni-free P2-Na0.67[Li0.22Mn0.78]O2. The Na0.75[Li0.15Ni0.15Mn0.7]O2 delivers a specific capacity of ≈160 mAh g−1 in the voltage region of 1.5–4.6 V at 0.1 C in Na cells. Combined experiments (galvanostatic cycling, neutron powder diffraction, X-ray absorption spectroscopy, X-ray photoelectron spectroscopy, and nuclear magnetic resonance (7Li NMR)) and theoretical studies (density functional theory calculations) confirm that Ni substitution not only increases the operating voltage and decreases voltage hysteresis but also improves the cycling stability by reducing Li migration from transition metal to Na layers. This research demonstrates the effect of Li and Ni co-doping in P2-type layered materials and suggests a new strategy of using Mn-rich cathode materials via oxygen redox with optimization of doping elements for SIBs.
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- 2022
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28. Engineering Transition Metal Layers for Long Lasting Anionic Redox in Layered Sodium Manganese Oxide
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Natalia Voronina, Jun Ho Yu, Hee Jae Kim, Najma Yaqoob, Olivier Guillon, Hyungsub Kim, Min‐Gi Jung, Hun‐Gi Jung, Koji Yazawa, Hitoshi Yashiro, Payam Kaghazchi, and Seung‐Taek Myung
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Biomaterials ,Electrochemistry ,Condensed Matter Physics ,Electronic, Optical and Magnetic Materials - Published
- 2022
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29. Modified Li
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Kazuki, Uchida, Takahiro, Ohkubo, Futoshi, Utsuno, and Koji, Yazawa
- Abstract
Li
- Published
- 2021
30. Chiral crystal-like droplets displaying unidirectional rotational sliding
- Author
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Rie Haruki, Takashi Kajitani, Mitsuhiro Shibayama, Ken Morishima, Masaki Takata, Takaaki Hikima, Kyuri Motokawa, Daisuke Hashizume, Atsuko Kosaka, Takanori Fukushima, Koji Yazawa, and Yoshiaki Shoji
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Materials science ,Mechanical Engineering ,Supramolecular chemistry ,Triphenylene ,02 engineering and technology ,General Chemistry ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,Rotation ,01 natural sciences ,0104 chemical sciences ,Crystal ,chemistry.chemical_compound ,chemistry ,Mechanics of Materials ,Chemical physics ,Liquid crystal ,General Materials Science ,Self-assembly ,0210 nano-technology ,Chirality (chemistry) ,Derivative (chemistry) - Abstract
The self-assembly of organic molecules into supramolecular materials with structural ordering beyond the nanometre scale is challenging. Here, we report the spontaneous self-assembly of a chiral discotic triphenylene derivative into millimetre-sized droplets. The structure of the droplets is characterized by high positional and orientational ordering and a three-dimensional integrity similar to that of single crystals. Notwithstanding, these assemblies slide when placed on a vertical substrate demonstrating their fluid nature. X-ray imaging shows that during the sliding process the internal crystal-like structure is maintained and that the droplets undergo clockwise or counterclockwise unidirectional rotation, depending on the chirality of their molecular components. Rheological measurements suggest that this rotational behaviour might result from the distinct yield stress between the (R)- and (S)-enantiomers. Overall, our findings demonstrate that molecular chirality can determine the movement direction of a supramolecular structure, thus expanding the fundamental understanding of the structure and dynamics of soft materials. A chiral discotic triphenylene derivative spontaneously forms millimetre-sized assemblies with high structural order and fluid-like behaviour.
- Published
- 2019
31. Realizing the Single-Phase Spinel-Type Sodium Titanium Oxide with the Li
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Mitsunori, Kitta, Toshikatsu, Kojima, Riki, Kataoka, Koji, Yazawa, and Kohei, Tada
- Abstract
Sodium titanium oxide with a spinel-type structure is suitable for the stable sodium-intercalation host for the negative electrode of sodium-ion batteries, such as the spinel-type lithium titanium oxide (Li
- Published
- 2020
32. Unraveling the Hydrogen Bond Network in a Theophylline–Pyridoxine Salt Cocrystal by a Combined X-ray Diffraction, Solid-State NMR, and Computational Approach
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Koji Yazawa, Federica Rossi, Paolo Cerreia Vioglio, Carlo Nervi, Michele R. Chierotti, Emanuele Priola, Valeria Giorgio, Simone Bordignon, and Roberto Gobetto
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Materials science ,Chemistry (all) ,Materials Science (all) ,Condensed Matter Physics ,Codrug ,Hydrogen bond ,02 engineering and technology ,General Chemistry ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,Cocrystal ,0104 chemical sciences ,Turn (biochemistry) ,Crystallography ,Solid-state nuclear magnetic resonance ,X-ray crystallography ,General Materials Science ,Density functional theory ,0210 nano-technology ,Single crystal - Abstract
The formation of a codrug, a cocrystal formed by two active pharmaceutical ingredients (APIs), between theophylline (THEO) and pyridoxine·HCl (PyrH+Cl–) is reported. The THEO PyrH+Cl– drug–drug cocrystal could turn out to be interesting in the pharmaceutical field because these two APIs are concurrently administered for asthma treatment. The codrug was characterized by a combined experimental and computational investigation by means of single crystal X-ray diffraction (SCXRD), solid-state NMR (SSNMR), and density functional theory (DFT) calculations. An exhaustive SSNMR study was performed to unravel the complex network of hydrogen bond interactions which was poorly defined by SCXRD. Several advanced two-dimensional SSNMR spectra such as 1H DQ MAS, 13C–1H HETCOR, 14N–1H J- and D-HMQC were acquired, taking advantage of the resolution and sensitivity improvement provided by indirect detection pulse sequences and very fast MAS at 70 kHz. These experiments, supported and completed by DFT calculations, were fu...
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- 2018
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33. A comparative study of the photocatalytic and optical properties of spinel-type titanates: A report for spinel sodium titanate
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Shingo Tanaka, Koji Yazawa, Mitsunori Kitta, Hiroaki Sakurai, and Kohei Tada
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Materials science ,Valence (chemistry) ,Spinel ,chemistry.chemical_element ,engineering.material ,Condensed Matter Physics ,Electronic, Optical and Magnetic Materials ,Inorganic Chemistry ,chemistry ,Rutile ,Materials Chemistry ,Ceramics and Composites ,engineering ,Surface roughness ,Photocatalysis ,Physical chemistry ,Density functional theory ,Physical and Theoretical Chemistry ,Spectroscopy ,Titanium - Abstract
The recent discovery of Na3LiTi5O12 (NTO), which possesses spinel symmetry ( Fd 3 ¯ m , #227) with the 8a site occupied by Na, has enabled investigations into the effect of the 8a-site cation on the physical properties of spinel titanates. Hence, in this study, the optical and photocatalytic properties of NTO were investigated and compared with those of spinel Li4Ti5O12 (LTO) and rutile TiO2. The bandgaps were estimated theoretically using hybrid density functional theory and experimentally using the ultraviolet–visible spectroscopy, and the obtained results were similar for both methods and spinel titanates. The valence- and conduction-band components of the spinel-type titanates were similar to those of other titanium oxides, and both NTO and LTO exhibited photocatalytic activity for sacrificial H2 evolution from water. However, although they have similar band structures and optical properties, the NTO photocatalytic activity was clearly lower than that of LTO. This can be attributed to the surface roughness and ease of defect formation in the NTO system, which hindered charge separation. These results indicate that the optical properties of spinel-type titanates can be tuned by replacing the cations at the 8a sites.
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- 2021
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34. Facile Material Design Concept for Co-Free Lithium Excess Nickel-Manganese Oxide as High-Capacity Positive Electrode Material
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Kei Kubota, Koji Yazawa, Mitsuharu Tabuchi, and Mitsunori Kitta
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Electrode material ,Materials science ,Renewable Energy, Sustainability and the Environment ,chemistry.chemical_element ,High capacity ,Material Design ,Condensed Matter Physics ,Manganese oxide ,Surfaces, Coatings and Films ,Electronic, Optical and Magnetic Materials ,Nickel ,Chemical engineering ,chemistry ,Materials Chemistry ,Electrochemistry ,Lithium - Abstract
High-capacity Li1+x(Ni0.3Mn0.7)1-xO2, (0 < x < 1/3) samples were synthesized by the coprecipitation–calcination method. Both electrochemical cycle and high-rate performances were drastically improved by selecting an N2 atmosphere as final calcination. Scanning transmission electron microscopy—energy dispersive X-ray spectroscopy analysis showed that the sample calcined in an N2 atmosphere had a more homogeneous transition metal distribution into primary particles than that calcined in air. The solid-state 7Li nuclear magnetic resonance data showed that electrochemically inactive domains were only diminished for the sample calcined in an N2 atmosphere after electrochemical activation. X-ray Rietveld analysis revealed that the suitable transition metal distribution and content of the samples were different from those of typical layered rock-salt materials. Only that calcined in an N2 atmosphere had no spinel formation during charging and no oxide ion insertion reaction during discharging. No positive Co substitution effect was observed under the optimized preparation conditions. At the 100th cycle, the discharge capacity was 216 mAh g−1, which corresponds to 87% of the initial capacity (251 mAh g−1) at optimizing synthetic condition.
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- 2021
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35. Congenital perineal urethrocutaneous fistula without rupture in a neonate
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Futoshi Matsui, Fumi Matsumoto, Koji Yazawa, and Satoko Matsuyama
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medicine.medical_specialty ,Urology ,Anorectal anomalies ,030232 urology & nephrology ,Perineum ,Pediatrics ,Congenital ,03 medical and health sciences ,0302 clinical medicine ,medicine ,Urethral diverticulum ,Urethrocutaneous fistula ,business.industry ,medicine.disease ,Diseases of the genitourinary system. Urology ,Surgery ,body regions ,Position (obstetrics) ,Urethra ,medicine.anatomical_structure ,030220 oncology & carcinogenesis ,RC870-923 ,medicine.symptom ,business ,Penis - Abstract
Congenital anterior urethrocutaneous fistula (CAUF) is a rare anomaly, commonly observed in the mid-shaft or more distal position of the penis. It can be seen in the perineum in anorectal anomalies or in cases of duplicated urethra. However, isolated CAUF opening into the perineum has not been reported. Herein, we present a case of congenital anterior urethral diverticulum and possible perineal urethrocutaneous fistula of an otherwise healthy neonate.
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- 2021
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36. NMR Spectroscopic Analysis of the Local Structure of Porous-Type Amorphous Alumina Prepared by Anodization
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Sachiko Ono, Hidetaka Asoh, Hideki Hashimoto, and Koji Yazawa
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Materials science ,Anodizing ,Inorganic chemistry ,Oxalic acid ,Oxide ,Amorphous silica-alumina ,Sulfuric acid ,02 engineering and technology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,0104 chemical sciences ,Surfaces, Coatings and Films ,Electronic, Optical and Magnetic Materials ,Amorphous solid ,chemistry.chemical_compound ,General Energy ,chemistry ,Chromic acid ,Physical and Theoretical Chemistry ,0210 nano-technology ,Phosphoric acid - Abstract
Alumina is classified as an intermediate oxide that cannot form a glass and is industrially used as a multifunctional material. Intensive studies on the atomistic structure of amorphous alumina have been conducted because a fundamental understanding of its structure can be meaningful to the design of new materials and devices. Here we focused on anodic alumina as a model material for clarifying the atomistic structure of amorphous alumina and prepared anion-free and anion-incorporated porous-type amorphous alumina by anodization using chromic acid electrolyte and typical electrolytes (e.g., sulfuric acid, oxalic acid, and phosphoric acid), respectively. The local structure around aluminum atoms in the anodic alumina was investigated by nuclear magnetic resonance spectroscopy. We found that the structure of anodic amorphous alumina comprises AlO4, AlO5, and AlO6 units with predominant fractions of AlO5. We also observed that the fraction of each unit was 37.7, 54.3, and 8.0%, with an average coordination n...
- Published
- 2017
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37. High-pressure carbon monoxide preserves rat kidney grafts from apoptosis and inflammation
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Naoyuki Hatayama, Masayuki Fujino, Naotsugu Ichimaru, Yoshitaka Isaka, Norio Nonomura, Shiro Takahara, Jun-ya Kaimori, Kunihiro Seki, Ryoichi Imamura, Koichi Tsutahara, Toyofumi Abe, Xiao-Kang Li, Yoichi Kakuta, Koji Yazawa, and Masayoshi Okumi
- Subjects
Male ,0301 basic medicine ,Adenosine ,Gene Expression ,Apoptosis ,030230 surgery ,Kidney ,medicine.disease_cause ,p38 Mitogen-Activated Protein Kinases ,Phosphatidylinositol 3-Kinases ,0302 clinical medicine ,Insulin ,Phosphorylation ,Carbon Monoxide ,Reverse Transcriptase Polymerase Chain Reaction ,Chemistry ,Graft Survival ,Organ Preservation ,Glutathione ,Cold Temperature ,Kidney Tubules ,medicine.anatomical_structure ,Reperfusion Injury ,Cytokines ,Inflammation Mediators ,medicine.medical_specialty ,Allopurinol ,Partial Pressure ,p38 mitogen-activated protein kinases ,Blotting, Western ,Organ Preservation Solutions ,Pathology and Forensic Medicine ,Proinflammatory cytokine ,03 medical and health sciences ,Raffinose ,Internal medicine ,medicine ,Animals ,Viaspan ,Molecular Biology ,Protein kinase B ,Inflammation ,Kidney metabolism ,Cell Biology ,medicine.disease ,Kidney Transplantation ,Oxygen ,030104 developmental biology ,Endocrinology ,Rats, Inbred Lew ,Immunology ,Proto-Oncogene Proteins c-akt ,Reperfusion injury ,Oxidative stress - Abstract
Renal ischemia–reperfusion (I/R) injury is unavoidable in kidney transplantation (KTx) and frequently influences both short- and long-term allograft survival. Carbon monoxide (CO) has attracted attention as a medical gas with anti-inflammatory and anti-apoptotic effects. We investigated a new strategy for organ preservation using ex vivo application of high-pressure CO in an experimental rat KTx model. We preserved kidney grafts using a high-pressure chamber filled with mixed gases composed of CO and O2. We found that cold I/R injury resulted in progressive deterioration of renal graft function in University of Wisconsin solution, whereas CO significantly improved renal function. We confirmed that CO decreased oxidative stress and mRNA expression of proinflammatory cytokines and inhibited tubular apoptosis in the early phases. Western blot analysis demonstrated that CO increased phosphatidylinositol-3 kinase and phosphorylation of Akt and p38 mitogen-activated protein kinase. Furthermore, CO significantly alleviated tubular injury scores and suppressed the development of interstitial fibrosis at 100 days after KTx. Thus, high-pressure mixed CO and O2 gases successfully preserved rat kidney grafts for 24 h by protecting tubular epithelial cells from apoptosis and inhibiting inflammation.
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- 2017
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38. 小児急性精巣上体炎の臨床的検討.
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Shunsuke Inoguchi, Futoshi Matsui, Satoko Matsuyama, Fuki Kondo, Shinta Suenaga, Koji Yazawa, and Fumi Matsumoto
- Published
- 2022
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39. Sequential delithiation behavior and structural rearrangement of a nanoscale composite-structured Li
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Keiji, Shimoda, Koji, Yazawa, Toshiyuki, Matsunaga, Miwa, Murakami, Keisuke, Yamanaka, Toshiaki, Ohta, Eiichiro, Matsubara, Zempachi, Ogumi, and Takeshi, Abe
- Subjects
Batteries ,Energy ,Article - Abstract
Lithium- and manganese-rich layered oxides (LMRs) are promising positive electrode materials for next-generation rechargeable lithium-ion batteries. Herein, the structural evolution of Li1.2Ni0.2Mn0.6O2 during the initial charge–discharge cycle was examined using synchrotron-radiation X-ray diffraction, X-ray absorption spectroscopy, and nuclear magnetic resonance spectroscopy to elucidate the unique delithiation behavior. The pristine material contained a composite layered structure composed of Ni-free and Ni-doped Li2MnO3 and LiMO2 (M = Ni, Mn) nanoscale domains, and Li ions were sequentially and inhomogeneously extracted from the composite structure. Delithiation from the LiMO2 domain was observed in the potential slope region associated with the Ni2+/Ni4+ redox couple. Li ions were then extracted from the Li2MnO3 domain during the potential plateau and remained mostly in the Ni-doped Li2MnO3 domain at 4.8 V. In addition, structural transformation into a spinel-like phase was partly observed, which is associated with oxygen loss and cation migration within the Li2MnO3 domain. During Li intercalation, cation remigration and mixing resulted in a domainless layered structure with a chemical composition similar to that of LiNi0.25Mn0.75O2. After the structural activation, the Li ions were reversibly extracted from the newly formed domainless structure.
- Published
- 2019
40. [A CASE OF URETERAL STENT ENCRUSTATION AFTER LAPAROSCOPIC PYELOPLASTY IN AN 11-YEAR-OLD GIRL]
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Futoshi Matsui, Koji Yazawa, Fumi Matsumoto, Kota Fujimoto, and Satoko Matsuyama
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medicine.medical_specialty ,Pyeloplasty ,business.industry ,Urology ,medicine.medical_treatment ,030232 urology & nephrology ,Stent ,Flexible ureteroscopy ,Lithotripsy ,Anastomosis ,equipment and supplies ,medicine.disease ,Pyuria ,Surgery ,03 medical and health sciences ,surgical procedures, operative ,0302 clinical medicine ,030220 oncology & carcinogenesis ,medicine ,Laparoscopic pyeloplasty ,cardiovascular diseases ,medicine.symptom ,business ,Hydronephrosis - Abstract
Stent encrustation is one of the most serious complications of using double J stents. The management of encrusted stent is challenging, especially in children. To date, only two pediatric cases of stent encrustation, at the expected timing of removal after pyeloplasty, have been reported. In this report, we present a case of ureteral stent encrustation after laparoscopic retroperitoneal pyeloplasty in an 11-year-old girl. She underwent dismembered pyeloplasty for pelvi-ureteric junction obstruction on the left side using a double J stent (6 F, 24 cm, Polaris ™ Ultra). Postoperative course was uneventful, except for mild bladder irritability and asymptomatic pyuria. Nine weeks later, an attempt to remove the stent was made under general anesthesia. This attempt was unsuccessful as the renal coil got stuck in the anastomotic position. A retrograde 6 F flexible ureteroscopy revealed an encrusted stent with calculi. After transurethral lithotripsy with a holmium: yttrium aluminum garnet (YAG) laser, the stent was extracted. Stone analysis showed struvite. At 8-months follow-up, she was stone-free and doing well with resolution of hydronephrosis.
- Published
- 2019
41. Effect of Drug-Polymer Interactions through Hypromellose Acetate Succinate Substituents on the Physical Stability on Solid Dispersions Studied by Fourier-Transform Infrared and Solid-State Nuclear Magnetic Resonance
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Masatoshi Karashima, Junpei Takeda, Koji Yazawa, Hitomi Okada, Kenjirou Higashi, Kunikazu Moribe, Yukihiro Ikeda, Kohsaku Kawakami, Yuya Ishizuka, and Keisuke Ueda
- Subjects
Magnetic Resonance Spectroscopy ,Polymers ,Substituent ,Pharmaceutical Science ,02 engineering and technology ,030226 pharmacology & pharmacy ,03 medical and health sciences ,chemistry.chemical_compound ,0302 clinical medicine ,Hypromellose Derivatives ,Drug Discovery ,Polymer chemistry ,Spectroscopy, Fourier Transform Infrared ,Magic angle spinning ,Fourier transform infrared spectroscopy ,chemistry.chemical_classification ,Hydrogen bond ,Chemistry ,Intermolecular force ,technology, industry, and agriculture ,Nuclear magnetic resonance spectroscopy ,Polymer ,021001 nanoscience & nanotechnology ,body regions ,Solid-state nuclear magnetic resonance ,Molecular Medicine ,0210 nano-technology - Abstract
The present study evaluated the specific intermolecular interactions between carbamazepine (CBZ) and substituents of hypromellose acetate succinate (HPMC-AS), as well as the mechanism of inhibition of recrystallization of solid dispersions (SDs) using Fourier-transform infrared (FTIR) and solid-state nuclear magnetic resonance (NMR) spectroscopy. CBZ and HPMC derivatives, including HPMC, hypromellose acetate (HPMC-A), and hypromellose succinate (HPMC-S), were spray-dried to prepare CBZ/polymer spray-dried samples (SPDs). CBZ/HPMC SPD and CBZ/HPMC-A SPD recrystallized within 10 days at 60 °C and 0% relative humidity, whereas CBZ/HPMC-S SPD maintained its amorphous state for a longer period. FTIR and solid-state NMR measurements using 13C cross polarization (CP), 1H single-pulse, and 1H-15N CP-based heteronuclear single quantum correlation filter experiment with very fast magic angle spinning (MAS) at 70 kHz identified molecular interactions in CBZ/polymer SPDs. Although the HPMC backbone and substituents did not interact notably with CBZ and disrupt CBZ-CBZ intermolecular interactions (formed in the amorphous CBZ), acetate and succinate substituents on HPMC-A and HPMC-S disrupted CBZ-CBZ intermolecular interactions through formation of CBZ/polymer interactions. The acetate substituent formed a hydrogen bond with the NH2 group of CBZ, whereas the succinate substituent formed molecular interactions with both the C═O and NH2 groups of CBZ. Formation of relatively strong molecular interactions between CBZ and the succinate substituent followed by disruption of CBZ-CBZ intermolecular interactions effectively stabilized the amorphous state of CBZ in CBZ/HPMC-S SPD. The correlation between CBZ-polymer interactions and ability of polymers to effectively inhibit CBZ recrystallization is reflected in various commercial HPMC-AS. For example, HPMC-AS LF grade, containing higher amounts of the succinate group, was found to effectively inhibit the recrystallization of CBZ through strong molecular interactions as compared with the HPMC-AS HF grade. The present study demonstrated that a detailed investigation of molecular interactions between the drug and the polymer using FTIR and solid-state NMR spectroscopy could contribute to a suitable selection of the SD carrier.
- Published
- 2019
42. Negative dielectric constant of water confined in nanosheets
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Masashi Okubo, Akira Sugahara, Kazuma Gotoh, Koji Yazawa, Satoshi Kajiyama, Yasunobu Ando, Atsuo Yamada, and Minoru Otani
- Subjects
0301 basic medicine ,Materials science ,Science ,General Physics and Astronomy ,02 engineering and technology ,Electrolyte ,Dielectric ,Electrochemistry ,Capacitance ,General Biochemistry, Genetics and Molecular Biology ,Article ,Ion ,law.invention ,03 medical and health sciences ,law ,Electric field ,Physics::Chemical Physics ,lcsh:Science ,Multidisciplinary ,business.industry ,General Chemistry ,021001 nanoscience & nanotechnology ,Capacitor ,030104 developmental biology ,Electrode ,Optoelectronics ,lcsh:Q ,0210 nano-technology ,business - Abstract
Electric double-layer capacitors are efficient energy storage devices that have the potential to account for uneven power demand in sustainable energy systems. Earlier attempts to improve an unsatisfactory capacitance of electric double-layer capacitors have focused on meso- or nanostructuring to increase the accessible surface area and minimize the distance between the adsorbed ions and the electrode. However, the dielectric constant of the electrolyte solvent embedded between adsorbed ions and the electrode surface, which also governs the capacitance, has not been previously exploited to manipulate the capacitance. Here we show that the capacitance of electric double-layer capacitor electrodes can be enlarged when the water molecules are strongly confined into the two-dimensional slits of titanium carbide MXene nanosheets. Using electrochemical methods and theoretical modeling, we find that dipolar polarization of strongly confined water resonantly overscreens an external electric field and enhances capacitance with a characteristically negative dielectric constant of a water molecule., Confinement within nanospace could significantly alter the properties of chemical species. Here the authors report the negative dielectric constant of water confined in nanosheets that can enhance the capacitance of electric-double layer capacitor electrodes.
- Published
- 2019
43. High-capacity Li-excess lithium nickel manganese oxide as a Co-free positive electrode material
- Author
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Koji Yazawa, Riki Kataoka, and Mitsuharu Tabuchi
- Subjects
Materials science ,Mechanical Engineering ,Composite number ,Analytical chemistry ,chemistry.chemical_element ,02 engineering and technology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,Electrochemistry ,01 natural sciences ,0104 chemical sciences ,law.invention ,Nickel ,Transition metal ,chemistry ,Mechanics of Materials ,law ,Phase (matter) ,General Materials Science ,Calcination ,Lithium ,0210 nano-technology ,Stoichiometry - Abstract
For the design of high-capacity and Co-free positive electrode material, stoichiometric LiNi1/2Mn1/2O2 and Li-excess Li1+x(NiyMn1-y)1-xO2 (0 3 ¯ m), but the sample has a biphasic composite of main Li-poor Li1-xTM1+xO2 (TM, transition metal) and minor Li-rich Li1+xTM1-xO2 phases after calcination below 950 °C. The fraction of the minor Li-rich phase decreased concomitantly with increasing calcination temperature. Only at 1000 °C was single-phase LiNi1/2Mn1/2O2 obtainable. The biphasic samples exhibited better electrochemical performance than that for the single-phase sample. Based on this result, two Li-excess Li1+x(NiyMn1-y)1-xO2 (0
- Published
- 2021
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44. Utilizing an Umbilical Ligament for Complex Ureteroneocystostomy
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Futoshi Matsui, Takuya Ito, Fumi Matsumoto, Satoko Matsuyama, Koji Yazawa, and Kenji Shimada
- Subjects
Male ,medicine.medical_specialty ,Adolescent ,Megaureter ,Urology ,Urinary Bladder ,030232 urology & nephrology ,Anastomosis ,Vesicoureteral reflux ,Umbilical Arteries ,03 medical and health sciences ,0302 clinical medicine ,Ureter ,030225 pediatrics ,medicine.artery ,medicine ,Humans ,Ureteral Diseases ,Child ,Retrospective Studies ,Ligaments ,Urinary bladder ,Umbilicus ,business.industry ,Anastomosis, Surgical ,Infant ,Umbilical artery ,medicine.disease ,Surgery ,Cystostomy ,medicine.anatomical_structure ,Child, Preschool ,Ligament ,Female ,Ectopic ureter ,business - Abstract
INTRODUCTION To overcome the tension of anastomosis between ureter and bladder for complex ureteroneocystostomy in children, we describe a novel technique utilizing an ipsilateral umbilical ligament (occluded umbilical artery) to fix the bladder. TECHNICAL CONSIDERATIONS From July 1991 to December 2013, 18 patients (13 girls, 5 boys) underwent our technique for complex ureteroneocystostomy. Median age at surgery was 61 months. The main indications for surgery were ectopic ureter in 9 patients, primary obstructive megaureter in 3, and persistent vesicoureteral reflux after surgery in 2. The ipsilateral umbilical ligament was ligated. A new hiatus was created craniolateral to the original hiatus. The submucosal tunnel was created trans-trigonally. The umbilical ligament was sutured to the whole bladder muscle at the hiatus. Ureteroneocystostomy was then performed. Mean duration of postoperative follow-up was 62.6 months. Seventeen patients underwent unilateral ureteroneocystostomy with our technique. One patient underwent bilateral ureteroneocystostomy with our technique on one side. Vesicoureteral reflux was not shown in 92.3% of patients and no signs of obstruction developed in any patients. No complications were encountered with our procedure. Conclusions Utilizing an umbilical ligament for ureteroneocystostomy to fix the bladder is an excellent option when the distal ureter creates tension in uretero-bladder anastomosis. This method seems to be applicable in many cases of complex ureteroneocystostomy in children.
- Published
- 2016
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45. A Case of Chromosomal Disorders of Sex Development with Transverse Testicular Ectopia Mimicking Mixed Gonadal Dysgenesis
- Author
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Futoshi Matsui, Kenji Shimada, Koji Yazawa, and Fumi Matsumoto
- Subjects
Male ,medicine.medical_specialty ,Pathology ,Urologic Surgical Procedures, Male ,Urology ,030232 urology & nephrology ,Diagnosis, Differential ,03 medical and health sciences ,0302 clinical medicine ,Testis ,Ureteroscopy ,medicine ,Humans ,Disorders of sex development ,Ultrasonography ,Gynecology ,Disorder of Sex Development, 46,XY ,Ectopic testis ,business.industry ,Infant, Newborn ,medicine.disease ,body regions ,medicine.anatomical_structure ,Hypospadias ,030220 oncology & carcinogenesis ,Persistent Müllerian duct syndrome ,Gonadal Dysgenesis, Mixed ,Testicular ectopia ,Mixed gonadal dysgenesis ,Differential diagnosis ,business ,Duct (anatomy) ,Follow-Up Studies - Abstract
Transverse testicular ectopia (TTE) is a rare form of ectopic testis observed in boys with a normal 46, XY karyotype. TTE can be associated with persistent Müllerian duct syndrome or other genital anomalies such as hypospadias. However, TTE concomitant with both persistent Müllerian duct remnants and hypospadias has never been reported in the literature. A case of chromosomal disorders of sex development with TTE and persistent Müllerian duct remnants, which was initially presumed to represent mixed gonadal dysgenesis, is presented.
- Published
- 2017
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46. A CASE OF DEXTRANOMER-HYALURONIC ACID COPOLYMER (Deflux®) IMPLANTS CALCIFICATION MIMICKING DISTAL URETERAL CALCULI
- Author
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Koji Yazawa, Kenji Shimada, Fumi Matsumoto, and Futoshi Matsui
- Subjects
medicine.medical_specialty ,medicine.diagnostic_test ,business.industry ,Urology ,030232 urology & nephrology ,urologic and male genital diseases ,medicine.disease ,Vesicoureteral reflux ,female genital diseases and pregnancy complications ,Endoscopy ,Surgery ,03 medical and health sciences ,0302 clinical medicine ,030220 oncology & carcinogenesis ,Dextranomer-hyaluronic acid copolymer ,medicine ,business ,Complication ,Radiological imaging ,Calcification - Abstract
Since 2011, endoscopic correction of vesicoureteral reflux using dextranomer-hyaluronic acid copolymer (Deflux®) has been widely accepted in Japan due to its safety and minimally invasive nature. However, long-term complications are unknown. We present a case of Deflux® implants calcification mimicking distal ureteral calculi in a 12-year-old boy with a history of Deflux® injection performed at three years of age for primary VUR. We should be aware of this complication to avoid misdiagnosis and unnecessary invasive examination such as radiological imaging or endoscopy.
- Published
- 2017
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47. Gynecological assessment in young adults with 46,XX congenital adrenal hyperplasia
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Koji Yazawa, Futoshi Matsui, Fumi Matsumoto, and Satoko Matsuyama
- Subjects
Pediatrics ,medicine.medical_specialty ,business.industry ,Urology ,Pediatrics, Perinatology and Child Health ,medicine ,Congenital adrenal hyperplasia ,Young adult ,medicine.disease ,business - Published
- 2020
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48. Which case is best for scrotal incision as the initial surgical approach in unilateral non-palpable testis?
- Author
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Koji Yazawa, Fumi Matsumoto, Satoko Matsuyama, and Futoshi Matsui
- Subjects
medicine.medical_specialty ,Surgical approach ,Scrotal incision ,business.industry ,Urology ,Pediatrics, Perinatology and Child Health ,medicine ,Non palpable ,business ,Surgery - Published
- 2020
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49. [A CASE OF PARATESTICULAR FIBROUS HAMARTOMA OF INFANCY]
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Makoto Takeuchi, Satoko Matsuyama, Takuya Okusa, Koji Yazawa, Futoshi Matsui, Fumi Matsumoto, and Keiko Matsuoka
- Subjects
medicine.medical_specialty ,business.industry ,Urology ,030218 nuclear medicine & medical imaging ,Benign Soft Tissue Tumor ,03 medical and health sciences ,Axilla ,0302 clinical medicine ,medicine.anatomical_structure ,030220 oncology & carcinogenesis ,Medicine ,Orchiectomy ,Radiology ,business ,Fibrous hamartoma of infancy ,Subcutaneous tissue - Abstract
Fibrous hamartoma of infancy (FHI) is a rare, benign soft tissue tumor arising from subcutaneous tissue in children during the first two years of life. The tumor is commonly found in the axilla, shoulder and upper arm. Paratesticular FHI is extremely rare. To date, only a case of paratesticular FHI has been reported in Japan. We present a case of paratesticular FHI in an 11-month-old boy who eventually needed orchiectomy due to local recurrence one month after the excision of the tumor. Ten months postoperatively, there was no sign of recurrence.
- Published
- 2018
50. Urinary Ascites Secondary to Bilateral Mid-ureteral Stenosis in a Neonate
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Masataka Kawamura, Kenji Shimada, Futoshi Matsui, Koji Yazawa, and Fumi Matsumoto
- Subjects
Male ,medicine.medical_specialty ,Urology ,Urinary system ,030232 urology & nephrology ,Constriction, Pathologic ,Urine ,urologic and male genital diseases ,Severity of Illness Index ,Constriction ,03 medical and health sciences ,0302 clinical medicine ,030225 pediatrics ,Severity of illness ,Ascites ,medicine ,Humans ,Obstructive uropathy ,business.industry ,Infant, Newborn ,medicine.disease ,Stenosis ,medicine.symptom ,Urinary tract obstruction ,business ,Urethral valve ,Ureteral Obstruction - Abstract
Urinary ascites is most commonly seen in fetuses and newborns with obstructive uropathy. The majority of cases are associated with lower urinary tract obstruction, such as posterior urethral valves. In this report, we present a unique case of neonatal urinary ascites caused by congenital supravesical obstruction. To date, neonatal urinary ascites secondary to bilateral mid-ureteral stenosis without a history of antenatal diagnosis has not been reported.
- Published
- 2018
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