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110 results on '"Cho, H. -D."'

1. Efficient Green Emission from Edge States in Graphene Perforated by Nitrogen Plasma Treatment

Author

Kovaleva, N N, Chvostova, D, Potůček, Z, Cho, H D, Fu, Xiao, Fekete, L, Pokorny, J, Bryknar, Z, Kugel, K I, Dejneka, A, Kang, T W, Panin, Gennady N, and Kusmartsev, F V

Subjects
Condensed Matter - Materials Science, Physics - Applied Physics
Abstract

Plasma functionalization of graphene is one of the facile ways to tune its doping level without the need for wet chemicals making graphene photoluminescent. Microscopic corrugations in the two-dimensional structure of bilayer CVD graphene having a quasi-free-suspended top layer, such as graphene ripples, nanodomes, and bubbles, may significantly enhance local reactivity leading to etching effects on exposure to plasma. Here, we discovered that bilayer CVD graphene treated with nitrogen plasma exhibits efficient UV-green-red emission, where the excitation at 250 nm leads to photoluminescence with the peaks at 390, 470, and 620 nm, respectively. By using Raman scattering and spectroscopic ellipsometry, we investigated doping effects induced by oxygen or nitrogen plasma on the optical properties of single- and bilayer CVD graphene. The surface morphology of the samples was studied by atomic force microscopy. It is revealed that the top sheet of bilayer graphene becomes perforated after the treatment by nitrogen plasma. Our comprehensive study indicates that the dominant green emission is associated with the edge defect structure of perforated graphene filled with nitrogen. The discovered efficient emission appearing in nitrogen plasma treated perforated graphene may have a significant potential for the development of advanced optoelectronic materials., Comment: 15 pages 5 Figures

Published
2019

16. Laparoscopic repeat liver resection for hepatocellular carcinoma: a multicentre propensity score-based study

Author

Morise, Z, primary, Aldrighetti, L, additional, Belli, G, additional, Ratti, F, additional, Belli, A, additional, Cherqui, D, additional, Tanabe, M, additional, Wakabayashi, G, additional, Cheung, T T, additional, Lo, C M, additional, Tanaka, S, additional, Kubo, S, additional, Okamura, Y, additional, Uesaka, K, additional, Monden, K, additional, Sadamori, H, additional, Hashida, K, additional, Kawamoto, K, additional, Gotohda, N, additional, Chen, K H, additional, Kanazawa, A, additional, Takeda, Y, additional, Ohmura, Y, additional, Ueno, M, additional, Ogura, T, additional, Suh, K S, additional, Kato, Y, additional, Sugioka, A, additional, Nitta, H, additional, Yasunaga, M, additional, Halium, N A, additional, Laurent, A, additional, Kaneko, H, additional, Otsuka, Y, additional, Kim, K H, additional, Cho, H-D, additional, Lin, C C-W, additional, Ome, Y, additional, Seyama, Y, additional, Troisi, R I, additional, Berardi, G, additional, Roteller, F, additional, Wilson, G C, additional, Geller, D A, additional, Soubrane, O, additional, Yoh, T, additional, Kaizu, T, additional, Kumamoto, Y, additional, Han, H-S, additional, Ekmekcigil, E, additional, Dagher, I, additional, Fuks, D, additional, Gayet, B, additional, Buell, J F, additional, Ciria, R, additional, Briceno, J, additional, O'Rourke, N, additional, Lewin, J, additional, Edwin, B, additional, Shinoda, M, additional, Abe, Y, additional, Hilal, M Abu, additional, and Alzoubi, M, additional

Published
2020
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20. Organic photodiodes on the base of cotton fibers/polymer composite.

Author

Zakirov, A. S., Yuldashev, Sh. U., Cho, H. D., Lee, J. C., Kang, T. W., and Mamadalimov, A. T.

Subjects
PHOTODIODES, ORGANIC electronics, ELECTRICAL properties of textile fibers, CONDUCTING polymers, COATED textiles, FIBROUS composites, SPECTRUM analysis
Abstract

In this paper, we report a study on the optical and electrical properties of pure cotton fibers from chemically surface and morphology modified and coated with poly [2-methoxy-5-(2-ethylhexyloxy)-1, 4-phenylenevinylene] (MEH-PPV) polymer samples by the dip-coating method. The treated and coated fibers properties were characterized by using scanning electron microscopy (SEM), photoluminescence, and I-V characteristics. The performance of fibers with the MEH-PPV polymer as a coating component was investigated and an excellent white-light emission which consists of blue-, green-, and red-light-emitting bands was demonstrated. I-V characteristics of the sandwich-type devices consisting of successive layers of ITO-PEDOT-PSS- CF/MEH-PPV-Ag show that upon light illumination the current increases in both the forward and reverse bias conditions which suggest that the photoresponse parameters for the heterojunction are better than the composite alone. [ABSTRACT FROM AUTHOR]

Published
2011
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31. Dependence of the optical properties of p-CdTe and p-Cd0.96Zn0.04Te on the bromine concentration in a bromine-methanol etching solution.

Author

Kim, M. D., Kang, T. W., Kim, G. H., Han, M. S., Cho, H. D., Kim, J. M., Jeoung, Y. T., and Kim, T. W.

Subjects
PHOTOLUMINESCENCE, METHANOL, BROMINE, SOLID state electronics
Abstract

Presents information on a study that performed photoluminescence measurement to investigate the dependence of the optical properties of p-CdTe and p-Cd[sub0.96]Zn[sub0.04]Te on various relative concentrations of bromine in a mixture of methanol and bromine. Experimental procedure; Results and discussion on the study.

Published
1993
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44. A study of the suppression of the high-temperature helium embrittlement in an oxide-particle dispersion strengthened alloy.

Author

ChongHong Zhang, Jang, J. S., YiTao Yang, Yin Song, YouMei Sun, Cho, H. D., and YunFan Jin

Subjects
HELIUM, HIGH temperatures, EMBRITTLEMENT, DISPERSION (Chemistry), TRANSMISSION electron microscopy, PHYSICAL & theoretical chemistry
Abstract

In this paper, an investigation on the micro-structure of an Fe-base oxide-dispersion-strengthened (ODS) alloy irradiated with high-energy 20Ne ions to different doses at a temperature around 0.5 Tm (Tm is the melting point of the alloy) is presented. Investigation with the transmission electron microscopy found that the accelerated growth of voids at grain-boundaries, which is usually a concern in conventional Fe-base alloys under conditions of inert-gas implantation, was not observed in the ODS alloy irradiated even to the highest dose (12000 at.ppm Ne). The reason is ascribed to the enhanced recombination of point defects and strong trapping of Ne atoms at the interfaces of the nano-scale oxide particles in grains. The study showed that ODS alloys have good resistance to the high-temperature inter-granular embrittlement due to inert-gas accumulation, exhibiting prominence of application in harsh situations of considerable helium production at elevated temperatures like in a fusion reactor. [ABSTRACT FROM AUTHOR]

Published
2008
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45. Infection with Helicobacter pylori Expressing the cagA Gene Is Not Associated with an Increased Risk of Developing Peptic Ulcer Diseases in Korean Patients.

Author

Park, S. M., Park, J., Kim, J. G., Cho, H. D., Cho, J. H., Lee, D. H., and Cha, Y. J.

Subjects
HELICOBACTER pylori infections, PEPTIC ulcer, DIAGNOSTIC use of polymerase chain reaction
Abstract

Background: Helicobacter pylori strains possessing the cagA gene have been postulated to have a disease-specific relationship to peptic ulcer. The purpose of this study was to investigate the relationship between the infection with Helicobacter pylori expressing the cagA gene and the development of peptic ulcer diseases in Korean patients. Methods: Genomic DNA and bacterial mRNA in the gastric mucosa were amplified by polymerase chain reaction (PCR) and reverse transcription PCR, using synthetic oligonucleotide primers to cagA genes to compare the prevalence of cagA genes in 35 patients with non-ulcer gastritis and 99 patients with gastric or duodenal ulcer disease (53 and 46, respectively). Two different primer sets for the cagA gene were used. The first primer set amplified a 298-bp region (nucleotides 1751-2048), and the second set amplified a 349-bp region (nucleotides 1228-1249). Results: The expected 298- and 349-bp PCR amplicons were identified as follows: 1) 32 (91.4%) and 30 (85.7%) of 35 non-ulcer gastritis patients; 2) 51 (96.2%) and 50 (94.3%) of 53 benign gastric ulcer patients; and 3) 46 (100.0%) and 40 (87.0%) of 46 duodenal ulcer patients, respectively. Conclusion: These results strongly suggest that the cagA gene will not prove to be a useful marker to distinguish disease-specific H. pylori strains in the development of peptic ulcer diseases in Korean patients. [ABSTRACT FROM AUTHOR]

Published
1998
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47. Homojunction p-n photodiodes based on As-doped single ZnO nanowire.

Author

Cho, H. D., Zakirov, A. S., Yuldashev, Sh. U., Ahn, C. W., Yeo, Y. K., and Kang, T. W.

Subjects
*ZINC oxide, *P-N-junction diodes, *PHOTODIODES, *ARSENIC, *DOPING agents (Chemistry), *NANOWIRES, *PHOTOVOLTAIC power generation
Abstract

Photovoltaic device was successfully grown solely based on the single ZnO p-n homojunction nanowire. The ZnO nanowire p-n diode consists of an as-grown n-type segment and an in-situ arsenic doped p-type segment. This p-n homojunction acts as a good photovoltaic cell, producing a photocurrent almost 45 times larger than the dark current under reverse-biased condition. Our results demonstrate that present ZnO p-n homojunction nanowire can be used as a self-powered ultraviolet photodetector as well as a photovoltaic cell, which can also be used as an ultralow electrical power source for nano-scale electronic, optoelectronic, and medical devices. [ABSTRACT FROM AUTHOR]

Published
2013
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49. Minimally Invasive Donor Hepatectomy for Adult Living Donor Liver Transplantation An International, Multi-institutional Evaluation of Safety, Efficacy and Early Outcomes

Author

Jai Young Cho, François Cauchy, Akihiko Soyama, Satoshi Ogiso, Fernando Pardo, H.-D. Cho, Takeshi Takahara, Choon Hyuck David Kwon, Olivier Scatton, Ho-Seong Han, Daniel Cherqui, Olivier Soubrane, Roberto Troisi, Talia Baker, Gabriella Pittau, Susumu Eguchi, Gyu-Seong Choi, Ki-Hun Kim, Shinji Uemoto, Fernando Rotellar, Aude Vanlander, Go Wakabayashi, Soubrane, O., Eguchi, S., Uemoto, S., Kwon, C. H. D., Wakabayashi, G., Han, H. -S., Kim, K. -H., Troisi, R., Cherqui, D., Rotellar, F., Cauchy, F., Soyama, A., Ogiso, S., Choi, G. -S., Takahara, T., Cho, J. Y., Cho, H. -D., Vanlander, A., Pittau, G., Scatton, O., Pardo, F., and Baker, T.

Subjects
medicine.medical_specialty, Rehabilitation, Liver transplantation, medicine.diagnostic_test, business.industry, Living donor, medicine.medical_treatment, Retrospective cohort study, Perioperative, Surgery, Transplantation, 03 medical and health sciences, Minimal access surgical procedure, 0302 clinical medicine, 030220 oncology & carcinogenesis, Laparotomy, Medicine, 030211 gastroenterology & hepatology, Hepatectomy, business, Complication, Laparoscopy, Outcomes assessments
Abstract

Objective Evaluating the perioperative outcomes of minimally invasive (MIV) donor hepatectomy for adult live donor liver transplants in a large multi-institutional series from both Eastern and Western centers. Background Laparoscopic liver resection has become standard practice for minor resections in selected patients in whom it provides reduced postoperative morbidity and faster rehabilitation. Laparoscopic approaches in living donor hepatectomy for transplantation, however, remain controversial because of safety concerns. Following the recommendation of the Jury of the Morioka consensus conference to address this, a retrospective study was designed to assess the early postoperative outcomes after laparoscopic donor hepatectomy. The collective experience of 10 mature transplant teams from Eastern and Western countries was reviewed. Methods All centers provided data from prospectively maintained databases. Only left and right hepatectomies performed using a MIV technique were included in this study. Primary outcome was the occurrence of complications using the Clavien-Dindo graded classification and the Comprehensive Complication Index during the first 3 months. Logistic regression analysis was used to identify risk factors for complications. Results In all, 412 MIV donor hepatectomies were recorded including 164 left and 248 right hepatectomies. Surgical technique was either pure laparoscopy in 175 cases or hybrid approach in 237. Conversion into standard laparotomy was necessary in 17 donors (4.1%). None of the donors died. Also, 108 experienced 121 complications including 9.4% of severe (Clavien-Dindo 3-4) complications. Median Comprehensive Complication Index was 5.2. Conclusions This study shows favorable early postoperative outcomes in more than 400 MIV donor hepatectomy from 10 experienced centers. These results are comparable to those of benchmarking series of open standard donor hepatectomy.

Published
2022

50. Multicenter Propensity Score-Based Study of Laparoscopic Repeat Liver Resection for Hepatocellular Carcinoma: A Subgroup Analysis of Cases with Tumors Far from Major Vessels

Author

Charles Chung Wei Lin, Francesca Ratti, Takashi Kaizu, Andrea Belli, David A. Geller, Masafumi Yasunaga, Alexis Laurent, Joseph F. Buell, Go Wakabayashi, Ibrahim Dagher, Shogo Tanaka, Hiroshi Sadamori, Katsuhiko Uesaka, Nasser Abdul Halim, Tomoaki Yoh, Naoto Gotohda, Ho-Seong Han, Ki-Hun Kim, Ruben Ciria, Kazuki Hashida, Hwui Dong Cho, Hironori Kaneko, Olivier Soubrane, Hiroyuki Nitta, Masaki Ueno, Gregory C. Wilson, Arimasa Miyama, Atsushi Sugioka, Toshiro Ogura, Yoshiaki Ohmura, Mohammad Alzoubi, Masahiro Shinoda, Yusuke Kumamoto, Giammauro Berardi, Kazuteru Monden, Kyung-Suk Suh, Bjørn Edwin, Minoru Tanabe, Tan To Cheung, Yuta Abe, Kazuyuki Kawamoto, Joel Lewin, Chung Mau Lo, Luca Aldrighetti, Zenichi Morise, Daniel Cherqui, Kuohsin Chen, Ela Ekmekcigil, Mohammed Abu Hilal, David Fuks, Roberto Ivan Troisi, Giulio Belli, Yuichiro Otsuka, Brice Gayet, Yusuke Ome, Yukiyasu Okamura, Fernando Rotellar, Javier Briceno, Nicholas O'Rourke, Akishige Kanazawa, Yasuji Seyama, Yutaka Takeda, Yutaro Kato, Shoji Kubo, Miyama, A., Morise, Z., Aldrighetti, L., Belli, G., Ratti, F., Cheung, T. -T., Lo, C. -M., Tanaka, S., Kubo, S., Okamura, Y., Uesaka, K., Monden, K., Sadamori, H., Hashida, K., Kawamoto, K., Gotohda, N., Chen, K., Kanazawa, A., Takeda, Y., Ohmura, Y., Ueno, M., Ogura, T., Suh, K. -S., Kato, Y., Sugioka, A., Belli, A., Nitta, H., Yasunaga, M., Cherqui, D., Halim, N. A., Laurent, A., Kaneko, H., Otsuka, Y., Kim, K. -H., Cho, H. -D., Lin, C. C. -W., Ome, Y., Seyama, Y., Troisi, R. I., Berardi, G., Rotellar, F., Wilson, G. C., Geller, D. A., Soubrane, O., Yoh, T., Kaizu, T., Kumamoto, Y., Han, H. -S., Ekmekcigil, E., Dagher, I., Fuks, D., Gayet, B., Buell, J. F., Ciria, R., Briceno, J., O'Rourke, N., Lewin, J., Edwin, B., Shinoda, M., Abe, Y., Hilal, M. A., Alzoubi, M., Tanabe, M., Wakabayashi, G., and Troisi, R.

Subjects
long-term outcome, Cancer Research, medicine.medical_specialty, Patient characteristics, Subgroup analysis, morbidity, Article, Resection, 03 medical and health sciences, 0302 clinical medicine, Blood loss, medicine, Stage (cooking), short-term outcome, RC254-282, business.industry, Neoplasms. Tumors. Oncology. Including cancer and carcinogens, hepatocellular carcinoma, laparoscopic liver resection, medicine.disease, Surgery, Oncology, 030220 oncology & carcinogenesis, Hepatocellular carcinoma, Propensity score matching, 030211 gastroenterology & hepatology, repeat surgery, Liver function, repeat liver resection, business
Abstract

Simple Summary Less morbidity is considered among the advantages of laparoscopic liver resection for HCC patients. However, our previous international, multi-institutional study of laparoscopic repeat liver resection (LRLR) failed to prove it. We hypothesize that these results may be since the study included complex cases performed during the procedure’s developing stage. To examine it, subgroup analysis based on propensity score were performed, defining the proximity of the tumors to major vessels as the complexity. A propensity score matching earned 115 each patient of LRLR and open repeat liver resection (ORLR) without the proximity to major vessels, and the outcomes were compared. With comparable operation time and long-term outcome, less blood loss and less morbidity were shown in LRLR group than ORLR. Even in its worldwide developing stage, LRLR for HCC patients could be beneficial in blood loss and morbidity for the patients with less complexity in surgery. Abstract Less morbidity is considered among the advantages of laparoscopic liver resection (LLR) for HCC patients. However, our previous international, multi-institutional, propensity score-based study of emerging laparoscopic repeat liver resection (LRLR) failed to prove this advantage. We hypothesize that these results may be since the study included complex LRLR cases performed during the procedure’s developing stage. To examine it, subgroup analysis based on propensity score were performed, defining the proximity of the tumors to major vessels as the indicator of complex cases. Among 1582 LRLR cases from 42 international high-volume liver surgery centers, 620 cases without the proximity to major vessels (more than 1 cm far from both first–second branches of Glissonian pedicles and major hepatic veins) were selected for this subgroup analysis. A propensity score matching (PSM) analysis was performed based on their patient characteristics, preoperative liver function, tumor characteristics and surgical procedures. One hundred and fifteen of each patient groups of LRLR and open repeat liver resection (ORLR) were earned, and the outcomes were compared. Backgrounds were well-balanced between LRLR and ORLR groups after matching. With comparable operation time and long-term outcome, less blood loss (283.3±823.0 vs. 603.5±664.9 mL, p = 0.001) and less morbidity (8.7 vs. 18.3 %, p = 0.034) were shown in LRLR group than ORLR. Even in its worldwide developing stage, LRLR for HCC patients could be beneficial in blood loss and morbidity for the patients with less complexity in surgery.

Published
2021

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