Evaluation of Hot Deformation and Dynamic Recrystallization Behaviors of Advanced Reduced-Activated Alloy (ARAA)

Sang‑Wook Kim,Hyeon‑Woo Son,Taek‑Kyun Jung,Young‑Bum Chun,Yi‑Hyun Park,Ji‑Woon Lee,Soong‑Keun Hyun 대한금속·재료학회 2019 METALS AND MATERIALS International Vol.25 No.4

The hot deformation behavior of advanced reduced-activation alloy (ARAA) was investigated using hot torsion tests. Thefl ow stress decreased as deformation temperature increased and as strain rate decreased. The fl ow behavior demonstratedthe typical dynamic recrystallization (DRX). Based on the constitutive analysis of peak stress, the activation energy for hotdeformation was found to be 330.3 kJ mol −1 . Peak stress was analyzed as a function of the Zener–Hollomon parameter, andcalculated and experimental values were in good agreement. A DRX kinetic model for ARAA was derived with deformationconditions based on the Avrami-type model. It was confi rmed that the volume fraction of dynamically recrystallized grainsincreased as deformation temperature increased and as strain rate decreased. The necklace structure and grain boundarybulging were observed in the deformed microstructure of ARAA. The suggested DRX mechanism for ARAA during hotworking is discontinuous DRX.

Effect of Hydride Reorientation on Delayed Hydride Cracking In Zr-2.5Nb Tubes

Yun Yeo Bum,Kim Young Suk,Im Kyung Soo,Cheong Yong Moo,Kim Sung Soo Korean Nuclear Society 2003 Nuclear Engineering and Technology Vol.35 No.6

The objective of this study is to investigate the reorientation of hydrides with applied stress intensity factor, the peak temperature and the time when to apply the stress intensity factor in a Zr-2.5Nb pressure tube during its thermal cycle treatment. Cantilever beam (CB) specimens with a notch of 0.5 mm in depth made from the Zr-2.5Nb tube were subjected to electrolytic hydrogen charging to contain 60 ppm H and then to a thermal cycle involving heating to the peak temperature of either 310 or $380^{\circ}C$, holding there for 50 h and then cooling to the test temperature of $250^{\circ}C$. The stress intensity factor of either 6.13 or $18.4\;MPa\sqrt{m}$ was applied at the beginning of the thermal cycle, at the end of the hold at the peak temperatures and after cooling to the test temperature, respectively. The reorientation of hydrides in the Zr-2.5Nb tube was enhanced with the increased peak temperature and applied stress intensity factor. Furthermore, when the CB specimens were subjected to $18.4\;MPa\sqrt{m}$ from the beginning of the thermal cycle, the reoriented hydrides occurred almost all over the Zr-2.5Nb tube, surprisingly suppressing the growth of a DHC crack. In contrast, when the CB specimens were subjected to the stress intensity factor at the test temperature, little reorientation of hydrides was observed except the notch region, leading the Zr-2.5Nb to grow a large DHC crack. Based on the correlation between the reorientation of hydrides and the DHC crack growth, a governing factor for DHC is discussed along with the feasibility of the Kim's DHC model.

Original Article : Geographic difference of epidemiological features of HCV infection in Korea

( Kyung Ah Kim ),( Sook Hyang Jeong ),( Eun Sun Jang ),( Young Seok Kim3 ),( Youn Jae Lee ),( Eun Uk Jung ),( In Hee Kim ),( Sung Bum Cho ),( Mee Kyung Kee ),( Chun Kang ) 대한간학회 2014 Clinical and Molecular Hepatology(대한간학회지) Vol.20 No.4

Background/Aims: The prevalence of hepatitis C virus (HCV) infection in Korea exhibits significant geographic variation, with it being higher in Busan and Jeonam than in other areas. The reason for this intranational geographic difference was investigated in this study by conducting a comparative analysis of the risk factors related to HCV infection among three geographic areas: the capital (Seoul), Busan, and the province of Jeolla. Methods: In total, 990 patients with chronic HCV infection were prospectively enrolled at 5 university hospitals located in Seoul (n=374), Busan (n=264), and Jeolla (n=352). A standardized questionnaire survey on the risk factors for HCV infection was administered to these three groups of patients, and a comparative analysis of the findings was performed. Results: The analysis revealed significant regional differences in exposure to the risk factors of HCV infection. By comparison with patients in Seoul as a control group in the multivariate analysis, patients in Busan had significantly more experience of invasive medical procedures, acupuncture, cosmetic procedures, and multiple sex partners. In contrast, patients in Jeolla were significantly older, and they had a higher prevalence of hepatocellular carcinoma, a lower prevalence of multiple sex partners, and had experienced fewer invasive procedures. Conclusions: There was a significant geographic difference in the exposure to potential risk factors of HCV infection between patients from the three studied regions. This may explain the regional variation of the prevalence of HCV infection in Korea, and should be taken into account when planning strategies for the prevention and management of HCV infection. (Clin Mol Hepatol 2014;20:361-367)

Pituitary Apoplexy due to Pituitary Adenoma Infarction

Kim, Joo-Pyung,Park, Bong-Jin,Kim, Sung-Bum,Lim, Young-Jin The Korean Neurosurgical Society 2008 Journal of Korean neurosurgical society Vol.43 No.5

Cause of pituitary apoplexy has been known as hemorrhage, hemorrhagic infarction or infarction of pituitary adenoma or adjacent tissues of pituitary gland. However, pituitary apoplexy caused by pure infarction of pituitary adenoma has been rarely reported. Here, we present the two cases pituitary apoplexies caused by pituitary adenoma infarction that were confirmed by transsphenoidal approach (TSA) and pathologic reports. Pathologic report of first case revealed total tumor infarction of a nonfunctioning pituitary macroadenoma and second case partial tumor infarction of ACTH secreting pituitary macroadenoma. Patients with pituitary apoplexy which was caused by pituitary adenoma infarction unrelated to hemorrhage or hemorrhagic infarction showed good response to TSA treatment. Further study on the predisposing factors of pituitary apoplexy and the mechanism of infarction in pituitary adenoma is necessary.

Factors Associated with Emotional Exhaustion in South Korean Nurses : A Cross-Sectional Study

Bum-Sung Choi,Ji Sun Kim,Dong-Woo Lee,Jong-Woo Paik,Boung Chul Lee,Jung Won Lee,Ho-Sung Lee,Hwa-Young Lee 대한신경정신의학회 2018 PSYCHIATRY INVESTIGATION Vol.15 No.7

Objective We examined associations between emotional exhaustion and selected sociodemographic and psychological factors among nurses in inpatient and outpatient nursing units at a university hospital in South Korea. Methods The participants were 386 nurses who completed the Maslach Burnout Inventory, a measure of emotional exhaustion. Psychological characteristics were evaluated, including hardiness, self-esteem, experience of trauma, resilience, perceived stress, and social support. Correlation analyses examined the relationships between emotional exhaustion with sociodemographic, occupational, and psychological characteristics. Linear regression was used to evaluate the associations between emotional exhaustion and the assessed characteristics. Results Higher emotional exhaustion scores were associated with greater depression, anxiety, traumatic experience, and perceived stress. Exhaustion was inversely associated with hardiness, self-esteem, resilience, and quality of life. The regression analysis indicated that gender, marriage, resilience, depression, perceived stress, and secondary traumatic stress were significantly associated with emotional exhaustion. Conclusion This study showed that psychological characteristics, such as resilience, depression, and secondary traumatic experiences, may cause emotional exhaustion. Understanding the needs of people with distinct demographic and psychological characteristics offers valuable direction for the development of intervention programs to prevent burnout among nurses.

Determination of Major Volatile Compounds in Korean Rice Wine Distillates

( Sang Bum Kim ) 한국응용생명화학회 2008 Journal of Applied Biological Chemistry (J. Appl. Vol.51 No.5

Notes : PCR-Based Detection and Molecular Genotyping of Enterotoxigenic Clostridium perfringens Isolates from Swine Diarrhea in Korea

( Sang Bum Kim ),( Hyeong Jun Lim ),( Wan Kyu Lee ),( In Gyun Hwang ),( Gun Jo Woo ),( Sang Ryeol Ryu ) 한국미생물생명공학회 2006 Journal of Microbiology and Biotechnology Vol.16 No.2

Soft Rot of Onion Bulbs Caused by Pseudomonas marginalis Under Low Temperature Storage

Kim, Yong-Ki,Lee, Seung-Don,Park, Chung-Sik,Lee, Sang-Bum,Lee, Sang-Yeob The Korean Society of Plant Pathology 2002 Plant Pathology Journal Vol.18 No.4

Soft rot occurred severely in onion bulbs stored under low temperature ($5^{\circ}C$) in storage houses at Changyoung, Kyungnam province, Korea in early 2000. Water-soaking and yellowish-brown lesions initially appeared on the outside scales of diseased onion bulbs, gradually progressing into the inside scales. Among the bacterial isolates obtained from the lesions, K-2 isolate was found to be responsible for the disease, which grew at a temperature range of from $0^{\circ}C$ to $36^{\circ}C$ with optimum temperature of $00^{\circ}$-$33^{\circ}C$. However, it showed strong pathogenicity to onion bulbs at $25^{\circ}C$ and $5^{\circ}C$ at 3 days and 2 months, respectively. The bacterium also caused soft rot on potato and showed hypersensitive reactions to tobacco and potato. The causal bacterium of onion soft rot was identified as Pseudomonas marginalis based on morphological, biochemical, and physiological characteristics including LOPAT, Soft rot in onion under low temperature storage caused by P. marginalis has not been previously reported.

Strategies for systems-level metabolic engineering.

Kim, Tae Yong,Sohn, Seung Bum,Kim, Hyun Uk,Lee, Sang Yup Wiley 2008 Biotechnology journal Vol.3 No.5

<P>Bio-based production of chemicals, fuels and materials is becoming more and more important due to the increasing environmental problems and sharply increasing oil price. To make these biobased processes economically competitive, the biotechnology industry explores new ways to improve the performance of microbial strains in fermentation processes. In contrast to the random mutagenesis and/or intuitive local metabolic engineering practiced in the past, we are now moving towards global-scale metabolic engineering, aided by various experimental and computational tools. This has recently led to some remarkable achievements for the overproduction of valueadded products. In this review, we highlight several relevant gene manipulation tools and computational tools using genome-scale stoichiometric models, and provide useful strategies for successful metabolic engineering along with selected exemplary studies.</P>

Soluble Epithin/PRSS14 Secreted from Cancer Cells Contains Active Angiogenic Potential

Kim, Sang-Bum,Lee, Deok-Jae,Jeong, Joo-Won,Kim, Chung-Ho,Park, Dong-Eun,Kim, Moon-Gyo Korean Society for Molecular and Cellular Biology 2010 Molecules and cells Vol.29 No.6

Epithin (PRSS14/matriptase/ST14), a type II membrane protein, is involved in progression of epithelial cancers and metastasis as well as in the normal epidermal barrier function. When activated, it translocates into the cell-cell contacts and sheds into media. In order to understand the specific mechanism during tumor progression, we tested the angiogenic potential of secreted form of epithin. Epithin produced from the cancer cells shed more in hypoxia and induced motility of endothelial cells. Epithin enhanced the migration and invasion of mouse and bovine endothelial cells without cell proliferation. Furthermore, soluble epithin induced endothelial differentiation in the assay of the human endothelial microvessel-like tube formation and in that of the chicken chorioallantoic membrane. The knock-down of epithin in the 427 thymoma cell line abolished the protease activity of secreted epithin fraction, reduced the invasion of endothelial cells through matrigel, and tube formation activity. Only specific antibodies abolished the migration of endothelial cell and the vessel morphogenesis, suggesting that epithin specifically functions in these systems. Therefore, we propose that the secreted epithin in the hypoxic cancer microenvironment plays a role as a proangiogenic factor, and can be modulated with specific antibodies.