Search

Your search keyword '"Saito, Tomonori"' showing total 504 results
Start Over Author "Saito, Tomonori"
504 results on '"Saito, Tomonori"'

155. Conspicuity of Malignant Liver Tumors on Diffusion-Weighted Imaging With Short tau Inversion Recovery After Gadolinium Ethoxybenzyl Diethylenetriaminepentaacetic Acid Administration.

Author

Iwanaga, Takashi, Fukukura, Yoshihiko, Saito, Tomonori, Sasaki, Masashi, Kumagae, Yuichi, Takumi, Koji, Hakamada, Hiroto, Fujisaki, Takuro, Saigo, Yasumasa, and Yoshiura, Takashi

Abstract

Background: Diffusion-weighted imaging (DWI) has been used for the detection and characterization of liver tumors because it has excellent contrast resolution. DWI using short tau inversion recovery (STIR) can improve tumor-to-liver contrast after gadolinium ethoxybenzyl diethylenetriaminepentaacetic acid (Gd-EOB-DTPA) administration that shortens the T1 relaxation of liver parenchyma.Purpose: To quantitatively and qualitatively compare the conspicuity of malignant liver tumors on DWI after Gd-EOB-DTPA administration between STIR and chemical shift selective (CHESS) sequences.Study Type: Single-institution retrospective study.Subjects: Fifty-seven patients with histologically confirmed malignant liver tumors were evaluated.Field Strength/sequence: Low b-value DWIs with STIR and CHESS sequences 18-20 minutes after Gd-EOB-DTPA administration were acquired at 1.5T.Assessment: Tumor contrast-to-noise ratio (CNR) and visual grade of tumor conspicuity on DWI between STIR and CHESS sequences were compared.Statistical Tests: Paired Student's t-test and the Wilcoxon signed rank-test were applied. P < 0.05 was considered statistically significant.Results: The mean tumor CNR and visual grade of tumor conspicuity on DWI were significantly higher for STIR than for CHESS (both P < 0.001). Regardless of the presence of chronic liver disease, the mean CNR (normal liver 33.5 ± 19.8 vs. 15.7 ± 12.2, P < 0.001; chronic liver disease 19.6 ± 11.0 vs. 9.2 ± 7.8, P < 0.001) and the visual conspicuity grade (normal liver 3.36 ± 0.64 vs. 2.56 ± 0.77, P < 0.001; chronic liver disease 2.94 ± 0.80 vs. 2.25 ± 0.84, P = 0.001) were significantly higher for STIR than for CHESS. Mean CNR and the visual conspicuity grade were also significantly higher for STIR than for CHESS in patients with hepatocellular carcinomas (CNR 18.1 ± 10.5 vs. 8.8 ± 7.2, P < 0.001; visual grade 2.88 ± 0.83 vs. 2.22 ± 0.87, P = 0.001) or metastases (CNR 35.0 ± 19.3 vs. 16.2 ± 13.1, P < 0.001; visual grade 3.45 ± 0.51 vs. 2.59 ± 0.73, P < 0.001).Data Conclusion: DWI using STIR may be more helpful for depicting malignant liver tumors after Gd-EOB-DTPA administration compared with DWI using CHESS.Level Of Evidence: 3 Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2019;49:565-573. [ABSTRACT FROM AUTHOR]

Published
2019
Full Text
View/download PDF

156. Polyalkenamers as Drop-In Additives for Ring-Opening Metathesis Polymerization: A Promising Upcycling Paradigm

Author

Foster, Jeffrey C., Damron, Joshua T., Zheng, Jackie, Guan, Chao, Popovs, Ilja, Rahman, Md. Anisur, Galan, Nicholas J., Dishner, Isaiah T., and Saito, Tomonori

Abstract

We report a distinct strategy to upcycle waste polyalkenamers such as polybutadiene into new, performance-advantaged materials by using them as drop-in additives for ring-opening metathesis polymerization (ROMP). The polyalkenamers serve as competent chain-transfer agents in ROMPs of common classes of cyclic olefin monomers, facilitating good molecular weight control, allowing low Ru catalyst loadings, and enabling efficient incorporation of the polyalkenamer into the synthesized polymeric material. We successfully demonstrate ROMP using model polyalkenamers and translate these learnings to leverage commercial polybutadiene and acrylonitrile butadiene styrene (ABS) as chain transfer agents for ROMP copolymerizations. Critically, our strategy is shown to be highly efficient and operationally simple, quantitatively incorporating the polyalkenamer and inheriting aspects of its thermomechanical performance. Our results highlight a promising pathway for the upcycling of polyalkenamers and provide an alternative to existing deconstruction and functional upcycling strategies.

Published
2024
Full Text
View/download PDF

158. Controlling Interfacial Dynamics: Covalent Bonding versus Physical Adsorption in Polymer Nanocomposites

Author

Holt, Adam P., primary, Bocharova, Vera, additional, Cheng, Shiwang, additional, Kisliuk, Alexander M., additional, White, B. Tyler, additional, Saito, Tomonori, additional, Uhrig, David, additional, Mahalik, J. P., additional, Kumar, Rajeev, additional, Imel, Adam E., additional, Etampawala, Thusitha, additional, Martin, Halie, additional, Sikes, Nicole, additional, Sumpter, Bobby G., additional, Dadmun, Mark D., additional, and Sokolov, Alexei P., additional

Published
2016
Full Text
View/download PDF

161. Unexpected Molecular Weight Effect in Polymer Nanocomposites

Author

Cheng, Shiwang, primary, Holt, Adam P., additional, Wang, Huiqun, additional, Fan, Fei, additional, Bocharova, Vera, additional, Martin, Halie, additional, Etampawala, Thusitha, additional, White, B. Tyler, additional, Saito, Tomonori, additional, Kang, Nam-Goo, additional, Dadmun, Mark D., additional, Mays, Jimmy W., additional, and Sokolov, Alexei P., additional

Published
2016
Full Text
View/download PDF

163. Ti3C2Tx(MXene)–polyacrylamide nanocomposite films

Author

Naguib, Michael, primary, Saito, Tomonori, additional, Lai, Sophia, additional, Rager, Matthew S., additional, Aytug, Tolga, additional, Parans Paranthaman, M., additional, Zhao, Meng-Qiang, additional, and Gogotsi, Yury, additional

Published
2016
Full Text
View/download PDF

168. Cover Picture: Effect of Cross-Link Density on Carbon Dioxide Separation in Polydimethylsiloxane-Norbornene Membranes (ChemSusChem 21/2015)

Author

Hong, Tao, primary, Niu, Zhenbin, additional, Hu, Xunxiang, additional, Gmernicki, Kevin, additional, Cheng, Shiwang, additional, Fan, Fei, additional, Johnson, J. Casey, additional, Hong, Eunice, additional, Mahurin, Shannon, additional, Jiang, De-en, additional, Long, Brian, additional, Mays, Jimmy, additional, Sokolov, Alexei, additional, and Saito, Tomonori, additional

Published
2015
Full Text
View/download PDF

169. Effect of Cross-Link Density on Carbon Dioxide Separation in Polydimethylsiloxane-Norbornene Membranes

Author

Hong, Tao, primary, Niu, Zhenbin, additional, Hu, Xunxiang, additional, Gmernicki, Kevin, additional, Cheng, Shiwang, additional, Fan, Fei, additional, Johnson, J. Casey, additional, Hong, Eunice, additional, Mahurin, Shannon, additional, Jiang, De-en, additional, Long, Brian, additional, Mays, Jimmy, additional, Sokolov, Alexei, additional, and Saito, Tomonori, additional

Published
2015
Full Text
View/download PDF

172. Synthesis and Characterization of Multiphase Block Copolymers: Influence of Functional Groups on Macromolecular Architecture

Author

Saito, Tomonori, Chemistry, Long, Timothy E., Davis, Richey M., McGrath, James E., Riffle, Judy S., and Wilkes, Garth L.

Subjects
multiphase block copolymer, morphology, ionomer, structure-property relationship, hydrogen-bonding, anionic polymerization
Abstract

Low molecular weight liquid polybutadienes (1000 – 2000 g/mol) consisting of 60 mol% 1,2-polybutadiene repeating units were synthesized via anionic telomerization and conventional anionic polymerization. Maintaining the initiation and reaction temperature less than 70 °C minimized chain transfer and enabled the telomerization to occur in a living fashion, which resulted in well-controlled molecular weights and narrow polydispersity indices. MALDI-TOF mass spectrometry confirmed that the liquid polybutadienes synthesized via anionic telomerization contained one benzyl end and one protonated end. Subsequently, 2-ureido-4[1H]-pyrimidone (UPy) quadruple hydrogen-bonding was introduced to telechelic poly(ethylene-co-propylene), and mechanical characterization of the composites with UPy-functionalized carbon nanotubes was performed. The composites enhanced the mechanical properties and the UPy-UPy association between the matrix polymer and carbon nanotubes prevented the decrease of an elongation at break. The matrix polymer was also reinforced without sacrificing the processability. Additionally, UPy groups were introduced to styrene-butadiene rubbers (SBRs). Introducing UPy groups to SBRs drastically changed the physical properties of these materials. Specifically, the SCMHB networks served as mechanically effective crosslinks, which raised Tg and enhanced the mechanical performance of the SBRs. Novel site-specific sulfonated graft copolymers, poly(methyl methacrylate)-g-(poly(sulfonic acid styrene)-b-poly(tert-butyl styrene)), poly(methyl methacrylate)-g-(poly(tert-butyl styrene)-b-poly(sulfonic acid styrene)), and the corresponding sodium sulfonate salts were successfully synthesized via living anionic polymerization, free radical graft copolymerization, and post-sulfonation strategies. The graft copolymers contained approximately 9 – 10 branches on average and 4 wt% of sulfonic acid or sodium sulfonate blocks adjacent to the backbone or at the branch terminus. The mobility of the sulfonated blocks located at the branch termini enabled the sulfonated blocks to more readily interact and form ionic aggregates. The glass transition temperatures (Tg) of the sulfonated graft copolymers with sulfonated blocks at the branch termini were higher than that of copolymers with sulfonated blocks adjacent to the backbone. More facile aggregation of sulfonated blocks at the branch termini resulted in the appearance of ionomer peaks in SAXS whereas ionomer peaks were not observed in sulfonated graft copolymers with sulfonated blocks adjacent to the backbone. In addition, similar analogues, novel site-specific sulfonated graft copolymers, poly(methyl methacrylate)-g-(poly(sulfonic acid styrene)-b-poly(ethylene-co-propylene)) (PMMA-g-SPS-b-PEP), poly(methyl methacrylate)-g-(poly(ethylene-co-propylene)-b-poly(sulfonic acid styrene)) (PMMA-g-PEP-b-SPS), and the corresponding sodium sulfonate salts were successfully synthesized. Estimated ï £N values predicted the phase separation of each block and differential scanning calorimetry (DSC) and dynamic mechanical analysis confirmed the phase separation of each block component of the graft copolymers. The aggregation of sulfonic acid or sodium sulfonate groups at the branch termini restricted the glass transition of the PEP block. This lack of the glass transition of the PEP block resulted in higher storage modulus than a sulfonated graft copolymer with sulfonated blocks adjacent to the backbone. The location of sulfonated blocks in both sulfonic acid and sodium sulfonate graft copolymers significantly affected the thermal, mechanical and morphological properties. Lastly, symmetric (16000 g/mol for each block) and asymmetric (14000 g/mol and 10000 g/mol for each block) poly(ethylene-co-propylene)-b-poly(dimehtylsiloxane) (PEP-b-PDMS) were synthesized using living anionic polymerization and subsequent hydrogenation. The onset of thermal degradation for the PEP-b-PDMS diblock copolymer was higher than 300 ºC and PEP-b-PDMS was more thermally stable than the precursor diblock copolymer, polyisoprene-b-PDMS. DSC analysis of PEP-b-PDMS provided Tg of PDMS -125 ºC, Tg of PEP -60 ºC, Tc of PDMS -90 ºC, and Tm of PDMS -46 and -38 ºC, respectively. Appearance of thermal transitions of each PEP and PDMS block revealed the formation of phase separation. Estimated Ï N also supported the phase separation. Ph. D.

Published
2008

175. Contact Doping with Sub‐Monolayers of Strong Polyelectrolytes for Organic Photovoltaics

Author

Mor, Gopal K., primary, Jones, David, additional, Le, Thinh P., additional, Shang, Zhengrong, additional, Weathers, Patrick J., additional, Woltermann, Megumi K. B., additional, Vakhshouri, Kiarash, additional, Williams, Bryan P., additional, Tohran, Sarah A., additional, Saito, Tomonori, additional, Verduzco, Rafael, additional, Salleo, Alberto, additional, Hickner, Michael A., additional, and Gomez, Enrique D., additional

Published
2014
Full Text
View/download PDF

186. Neuroendocrine tumor G3: a pancreatic well-differentiated neuroendocrine tumor with a high proliferative rate.

Author

Tanaka, Hiroki, Matsusaki, Shimpei, Baba, Youichirou, Isono, Yoshiaki, Kumazawa, Hiroaki, Sase, Tomohiro, Okano, Hiroshi, Saito, Tomonori, Mukai, Katsumi, and Kaneko, Hiroshi

Abstract

A 68-year-old man was referred to our hospital because of left upper quadrant pain. Contrast enhanced computed tomography showed a low density mass with delayed contrast effects as well as para-aortic node swelling with homogenous contrast effects. Histological examination of specimens obtained by endoscopic ultrasound fine needle aspiration revealed a pancreatic neuroendocrine tumor (NET) G2, according to the World Health Organization 2010 classification, and lymph node metastasis. Distal pancreatectomy and lymph node dissection were performed. On histological examination, the tumor showed well-differentiated morphology with an organoid pattern. The Ki67 labeling index was 21.6 %, and the mitotic count was 25/10 high power fields. As mentioned above, we made a final diagnosis of the lesion as 'NET G3,' because the tumor presented with well-differentiated morphology. Chemotherapy with Everolimus was administered. Liver metastasis occurred 11 months after the first operation, and a partial hepatectomy was performed. Histological findings were similar to those of the first operation. Herein we present a case of pancreatic well-differentiated neuroendocrine tumor with a high proliferative rate referred to as 'NET G3,' and review the relevant literature. [ABSTRACT FROM AUTHOR]

Published
2015
Full Text
View/download PDF

187. A case of a resectable single hepatic epithelioid hemangioendothelioma with characteristic imaging by ADC map.

Author

Okano, Hiroshi, Nakajima, Hideki, Tochio, Tomomasa, Suga, Daisuke, Kumazawa, Hiroaki, Isono, Yoshiaki, Tanaka, Hiroki, Matsusaki, Shimpei, Sase, Tomohiro, Saito, Tomonori, Mukai, Katsumi, Nishimura, Akira, Matsushima, Nobuyoshi, Baba, Youichirou, Murata, Tetsuya, Hamada, Takashi, and Taoka, Hiroki

Abstract

A 47-year-old woman with a single-nodule hepatic tumor was referred to our hospital. She had no symptoms. The tumor was located at the surface of the right lobe of the liver; it showed peripheral low signal intensity on a magnetic resonance imaging apparent diffusion coefficient (ADC) map, and an influx of blood flow into the peripheral area of the tumor at the early vascular phase on perflubutane microbubble (Sonazoid) contrast-enhanced (CE) ultrasonography. Since we suspected a malignant tumor, the patient underwent surgical resection. The hepatic tumor was resected curatively. Pathological examination revealed that the tumor was composed of epithelioid cells with an epithelioid structure and/or cord-like structure. Immunohistochemical staining was positive for cluster of differentiation 34 and factor VIII-related antigen. Based on the above, a final diagnosis of hepatic epithelioid hemangioendothelioma (EHE) was made. Hepatic EHE is a rare hepatic tumor: only a few cases of hepatic EHE with curative resection have been reported. We were unable to reach a diagnosis of hepatic EHE by imaging studies; however, an ADC map was useful in showing the malignant potential of the tumor, and CE ultrasonography was useful in revealing the peripheral blood flow of the tumor. When an unusual hepatic mass is encountered, hepatic EHE should be kept in mind, and the mass should be inspected with more than one imaging modality, including an ADC map, in the process of differential diagnosis. [ABSTRACT FROM AUTHOR]

Published
2015
Full Text
View/download PDF

Catalog

Books, media, physical & digital resources
See catalog results