Tuning the Microstructure and Mechanical Properties of Cold Sprayed Equiatomic CoCrFeMnNi High-Entropy Alloy Coating Layer

Ji‑Eun Ahn,Young‑Kyun Kim,Sang‑Hoon Yoon,Kee‑Ahn Lee 대한금속·재료학회 2021 METALS AND MATERIALS International Vol.27 No.7

An equiatomic CoCrFeMnNi high entropy alloy (HEA) coating layer was prepared via a cold spray (CS) process. In orderto control the microstructure and nano-indentation properties of the CS HEA, heat treatments were employed. CS HEAcoating layer showed a heterogeneous microstructure where ultra-fine grains were formed at the particle interfaces, whilecoarse grains were formed inside the particles. Furthermore, deformation twins (DTs) were also formed inside the particlesdue to severe plastic deformation (SPD) in each particle generated during the CS deposition. For the 550 °C heat treatment(HT), fine Cr-rich precipitates were additionally formed at the grain boundary and particle boundary. By contrast, recrystallizationoccurred during 850 °C HT, while the size of the Cr-rich precipitate increased. The nano-indentation hardness ofthe CS HEA coating layer was 10.9 GPa, which was ~ 3 times higher than that of the conventional cast HEA. The superiorhardness of the CS HEA might has been enabled due to the combination of the high dislocation density, DTs, and ultra-finegrains. Based on the results above, the strategy to control the microstructure and mechanical properties through HT of theequiatomic CoCrFeMnNi HEA coating layer prepared via the CS process has been discussed.

A Multi-Center Educational Research Regarding Breastfeeding for Pediatrics Residents in Korea

Yong Sung Choi,정성훈,김은선,Eun Sun Kim,Eunhee Lee,Euiseok Jung,So-Yeon Lee,이우령,Hye Sun Yoon,Yong Joo Kim,Ji Kyoung Park,Son Moon Shin,Ellen Ai-Rhan Kim 대한신생아학회 2022 Neonatal medicine Vol.29 No.1

Purpose: Pediatricians have a significant responsibility to educate mothers about the importance of breastfeeding. However, there have been minimal efforts in the courses of resident training in Korea. The purpose of this study is to evaluate the change in knowledge and attitude before and after a 4-week breastfeeding educational intervention among multicenter residents. Methods: Prospective interventional educational research was designed for residents at eight training hospitals in Korea. Institutional reviews were obtained in each hospital. The education curriculum consisted of 14 courses regarding breastfeeding theory and practice. These materials were used to teach pediatric residents for 4 weeks. Knowledge-based tests were administered before the course, and re-tests were administered after the course using different test items of similar levels. Test scores and survey responses were compared before and after the intervention. Results: A total of 73 residents (1st year 20, 2nd year 23, 3rd year 16, and 4th year residents 14) from eight training hospitals completed the intervention. Their average age was 30.3±2.9 years, 17 (23.3%) were male, 22 (30.1%) were married, and eight had more than one child of their own. The mean pre-test score was 61.8±13.4 and the mean post-test score was 78.3±7.5 (P<0.001). The inter-grade difference in the score was significant in the pre-test (P=0.005), but not significant in the post-test (P=0.155). There were more responses of obtaining confidence after the intervention (P<0.001). Conclusion: In our study, pediatric residents showed improvement in their knowledge and confidence level after 4 weeks of the breastfeeding curriculum. This will provide a basis for future policymaking in the training of pediatric residents regarding breastfeedReceived: 6 January 2022 Revised: 15 February 2022 Accepted: 15 February 2022 Correspondence to: Ellen Ai-Rhan Kim, MD Department of Pediatrics, Asan Medical Center, University of Ulsan College of Medicine, 88 Olympic-ro 43-gil, Songpa-gu, Seoul 05505, Korea Tel: +82-2-3010-3390 Fax: +82-2-3010-6978 E-mail: arkim@amc.seoul.kr A Multi-Center Educational Research Regarding Breastfeeding for Pediatrics Residents in Korea Yong-Sung Choi, MD,PhD1, Sung-Hoon Chung, MD, PhD2, Eun Sun Kim, MD, PhD3, Eun Hee Lee, MD4, Euiseok Jung, MD5, So Yeon Lee, MD, PhD5, Wooryoung Lee, MD6, Hye Sun Yoon, MD, PhD7, Yong Joo Kim, MD, PhD8, Ji Kyoung Park, MD, PhD9, Son Moon Shin, MD, PhD9, and Ellen Ai-Rhan Kim, MD, PhD5 1Department of Pediatrics, Kyung Hee University Hospital, Seoul, Korea 2Department of Pediatrics, Kyung Hee University Hospital at Gangdong, Seoul, Korea 3Department of Pediatrics, Kangwon National University Hospital, Chuncheon, Korea 4Department of Pediatrics, Korea University Anam Hospital, Seoul, Korea 5Department of Pediatrics, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea 6Department of Pediatrics, Soonchunhyang University Seoul Hospital, Seoul, Korea 7Department of Pediatrics, Nowon Eulji Medical Center, Eulji University, Seoul, Korea 8Department of Pediatrics, Hanyang University Seoul Hospital, Seoul, Korea 9Department of Pediatrics, Inje University Busan Paik Hospital, Busan, Korea Neonatal Med 2022 February;29(1):28-35 https://doi.org/10.5385/nm.2022.29.1.28 pISSN 2287-9412 . eISSN 2287-9803 Copyright(c) 2022 By Korean Society of Neonatology This is an Open-Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http:// creativecommons.org/licenses/by-nc/4.0), which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited. Original Article 29 Neonatal Med 2022 February;29(1):28-35 https://doi.org/10.5385/nm.2022.29.1.28 ing in Korea.

A case report of quadruple cancer in a single patient including the breast, rectum, ovary, and endometrium

노수경,Ji Yeong Yoon1,최철훈,Ui Nam Ryoo,Chang Ohk Sung,김태중,배덕수,김병기 대한부인종양학회 2008 Journal of Gynecologic Oncology Vol.19 No.4

Multiple primary cancer is defined as the multiple occurrence of malignant neoplasms in the same individual. Due to the development of new diagnostic techniques and the rise in long-term survival of cancer, reports of multiple primary cancers have gradually increased. Herein, we describe the case of a 68-year-old female patient with quadruple primary cancer of the breast, rectum, ovary, and endometrium. For its great rarity, we report this case with a review of the literature. Multiple primary cancer is defined as the multiple occurrence of malignant neoplasms in the same individual. Due to the development of new diagnostic techniques and the rise in long-term survival of cancer, reports of multiple primary cancers have gradually increased. Herein, we describe the case of a 68-year-old female patient with quadruple primary cancer of the breast, rectum, ovary, and endometrium. For its great rarity, we report this case with a review of the literature.

Do We Still Use The Camitta"s Criteria For Severe Aplastic Anemia?

( Hyun Hwa Yoon1 ),( Sung Hyun Kim1 ),( Ji Hyun Lee ),( Seok Jae Huh ),( Suee Lee ),( Sung Yong Oh ),( Hyuk Chan Kwon ),( Hyo Jin Kim ) 대한내과학회 2011 대한내과학회 추계학술대회 Vol.2011 No.-

Circulating Concentrations of C-Peptide and Colorectal Adenoma

( Yoon Ji Choi ),( Young Ha Kim ),( Chang Ho Cho ),( Sung Hi Kim ),( Jung Eun Lee ) 한국임상영양학회 2014 Clinical Nutrition Research Vol.3 No.1

Hyperinsulinemia may increase the risk of colorectal neoplasia because of its mitogenic and antiapoptotic properties, which have a growth-promoting effect. We examined the association between circulating concentrations of C-peptide, a biomarker of insulin secretion, and colorectal adenoma prevalence in a case-control study of Korean adults. A total of 364 participants (112 cases and 252 controls) were included. Participants who underwent a colonoscopy completed questionnaires and provided blood samples. We used multivariate logistic regression models to obtain odds ratios (ORs) and 95% confidence intervals (CIs) for colorectal adenoma. Circulating concentrations of C-peptide were not associated with colorectal adenoma; the multivariate OR (95% CI) was 0.95 (0.51-1.75) comparing the highest tertile with the lowest tertile (p for trend = 0.91). When we used a conditional logistic regression model by fasting status and sex matching, there was still no association (OR = 0.92; 95% CI = 0.43-1.99) when comparing the highest tertile with the lowest tertile. We observed no association between circulating concentrations of C-peptide and colorectal adenoma prevalence in Korean adults.

The Learning Curve for Colorectal Stent Insertion for the Treatment of Malignant Colorectal Obstruction

( Ji Hoon Lee ),( Jin Young Yoon ),( Soo Jung Park ),( Sung Pil Hong ),( Tae Il Kim ),( Won Ho Kim ),( Jae Hee Cheon ) 대한소화기학회 2012 Gut and Liver Vol.6 No.3

Background/Aims: We aimed to assess the effectiveness of self-expanding metal stent (SEMS) insertion by evaluating the learning curve in relation to the experience of an endos-copist. Methods: We retrospectively analyzed the outcomes of 120 SEMS insertion procedures performed by one en-doscopist in patients with malignant colorectal obstruction. We compared the technical and clinical success rates, com-plication rates, and duration of the procedures by quartiles. Results: The mean age of the patients (76 men and 44 women) was 64.6 years. The overall technical success rate was 95.0% (114/120), and the clinical success rate was 90.0% (108/120). The median procedure duration was 16.2 minutes (range, 3.4 to 96.5 minutes). From the first to the last quartile, the technical success rates were 90.0%, 96.7%, 96.7%, and 96.7% (p=0.263), and the clinical success rates were 90.0%, 90.0%, 96.7%, and 83.3% (p=0.588), respec-tively. Procedure-related complications were observed in 28 patients (23.3%). The complication rates for SEMS insertion when patients were divided by quartiles were 26.7%, 23.3%, 10.0%, and 33.3% (p=0.184), respectively. Moreover, the number of stents per procedure was 1.13, 1.03, 1.00, and 1.00 (p=0.029), respectively. The median duration of SEMS insertion decreased significantly, 20.9 to 14.8 minutes after the first 30 procedures (p=0.005). Conclusions: An experi-enced endoscopist was able to perform the SEMS insertion procedure easily and effectively after performing 30 SEMS insertions. (Gut Liver 2012;6:328-333)

Analysis of the occupational stress of Korean surgeons : a pilot study

Sang-Hee Kang,Yoon-Jung Boo,Ji-Sung Lee,Woong-Bae Ji,Byoung-Eun Yoo,Ji-Young You 대한외과학회 2013 Annals of Surgical Treatment and Research(ASRT) Vol.84 No.5

Purpose: Surgeons serve one of the most challenging and stressful professions. Ineffective control of occupational stress leads to burnout of the surgeon. The aim of this study was to obtain preliminary data on the sources and the degree of stress of surgeons and to determine the feasibility of the survey. Methods: A total of 63 surgeons in our three affiliated hospitals were enrolled in this study. Fifty-five questions were used to assess the demographics, characteristics and Korean occupational stress scale (KOSS), which were prepared and validated by the National Study for Development and Standardization of Occupational Stress. Results: Forty-seven of the 63 surgeons participated in this study (74.6%). The mean KOSS score of the survey was 50.9 ± 8.55, which was significantly higher than that of other professions (P < 0.01). Drinking and smoking habits were not related to the KOSS score. Doing exercise was related to a low KOSS score in terms of low KOSS total score (P < 0.01). Average duty hours (P < 0.01) and night duty days per week (P = 0.01) were strongly related to higher KOSS in the linear regression analysis. Conclusion: This is the first study to evaluate job stress of surgeons in Korea. This study showed that Korean Surgeons had higher occupational stress than other Korean professions. A larger study based on this pilot study will help generate objective data for occupational stress of Korean Surgeons by performing a survey of the members of the Korean Surgical Society.

Family history of chronic renal failure is associated with malnutrition in Korean hemodialysis patients

Ji-Yun Hwang,Ju-Hyun Cho,Yoon Jung Lee,Sang Pil Jang,Wha Young Kim 한국영양학회 2009 Nutrition Research and Practice Vol.3 No.3

The present study was to investigate the nutritional status and factors related to malnutrition in end-stage renal disease (ESRD) patients requiring hemodialysis (HD) in South Korea. Subjects were ESRD outpatients from general hospitals or HD centers in Seoul referred to the dialysis clinic for maintenance HD care. A total of 110 patients (46 men and 64 women; mean ages 58.6 ± 1.0 y) were eligible for this study. The family history of chronic renal failure (CRF) was considered positive if a patient reported having either a first-degree or second-degree relative with CRF. Malnutrition was defined as a triceps skinfold thickness or mid-arm muscle circumference below the fifth percentile for age and sex and forty-seven of the 110 patients were malnourished. Almost all (94%) patients had anemia (hemoglobin: <13 g/dL for men and <12 g/dL for women). Energy intake was below the recommended intake levels of energy [30-35 ㎉/㎏ ideal body weight (IBW)] and protein (1.2 g/㎏ IBW) in 60% of patients. The duration of HD was longer in malnourished HD patients (P=0.0095). Malnutrition was more prevalent in women (P=0.0014), those who never smoked (P=0.0007), nondiabetic patients (P=0.0113), and patients with bone diseases (P=0.0427), adequate HD (spKt/V≥1.2) (P=0.0178), and those with a family history of CRF (P=0.0255). Multiple logistic regression was used to examine the relationship between malnutrition and potential risk factors. After adjusting for age, sex, and other putative risk factors for malnutrition, the OR for malnutrition was greater in HD patients with a family history of CRF (OR, 3.290; 95% CI, 1.003-10.793). Active nutrition monitoring is needed to improve the nutritional status of HD patients. A family history of CRF may be an independent risk factor for malnutrition in Korean HD patients. A follow-up study is needed to investigate whether there is a causal relationship between a family history of CRF and malnutrition in Korean ESRD patients.

Comparison of nutrient compositions and pharmacological effects of steamed and freeze-dried mature silkworm powders generated by four silkworm varieties

Ji, Sang-Dock,Nguyen, Phuong,Yoon, Sun-Mi,Kim, Kee-Young,Son, Jong Gon,Kweon, Hae-young,Koh, Young Ho 한국응용곤충학회 2017 Journal of Asia-Pacific Entomology Vol. No.

<P>The mulberry silkworm, Bombyx mori, has provided valuable fabrics and foods to humans for > 5000 years. We invented the protocol for processing mature silkworms, which contain various functional substances, into edible steamed and freeze-dried mature silkworm powders (SMSPs). However, previously reported technique could not create powders smaller than 0.1 mm and had problems with loss of product due to large SMSP particles sticking to hammer mill machines during the pulverizing process. To resolve these problems, we invented a new pulverization protocol that could create particle sizes smaller than 0.01 mm. Reduced particle sizes in SMSPs offered several advantages: increased nutrient contents in the nutritional aspect and extended life expectancy and enhanced locomotor activity in the pharmacological aspect. In addition, four SMSPs were enriched with flavonoids, poly-phenols, and vitamins that are known to act as oxidative stress inhibitors in cells and tissues. Nutrient and phytochemical composition analysis results suggested that this is why SMSPs extended health-spans and inhibited onset of Parkinson's disease. Although most nutrient and phytochemical compositions among the four SMSPs were comparable, certain nutrients and chemicals were significantly higher in certain SMSPs. Therefore, further research using these four SMSPs will identify the specific health-promoting effects of each SMSP, resulting in the further development of sericulture and entomology.</P>

The effects of cryoprotectant on sperm proteome during cryopreservation

Sung-Jae Yoon,Md Saidur Rahman,Ye-Ji Kim,Do-Yeal Ryu,Amena Khatun,Woo-Sung Kwon,Myung-Geol Pang 한국발생생물학회 2015 한국발생생물학회 학술발표대회 Vol.2015 No.9

Cryopreservation allows for the advances of the reproductive technique and livestock industry. However, cryopreservation inevitably causes various types of stress, such as cold shock, osmotic stress, and ice crystal formation, thereby reducing fertility. Although cryoprotectant agent (CPA) is added to protect spermatozoa from freezing damage during cryopreservation, it has intrinsic toxicity that can affect components of the sperm membrane. Moreover, the addition of CPA induces osmotic stress and excessive reactive oxygen species (ROS) generation, resulting in disruption of mitochondrial membrane potential, alteration of membrane permeability, and damage of sperm surface proteins. To identify the effects of CPA to spermatozoa, we analyzed the sperm movement, capacitation status, and viability using computer-assisted sperm analysis and Hoechst 33258/chlortetracycline fluorescence staining. Moreover, we performed two-dimensional electrophoresis to find protein markers related CPA addition in cryo processes. CPA addition reduced sperm motility (%), viability (%), and non-capacitated spermatozoa, whereas acrosome-reacted spermatozoa increased significantly (p<0.05). Following addition of CPA, a total of ten proteins were altered their expression (eight increased, two decreased) (>3 fold, p<0.05). Among these, four differentially expressed proteins were related to several canonical pathways, such as the ephrinR-actin, ROS metabolism, actin cytoskeleton assembly, actin cytoskeleton regulation, and respiratory chain and oxidative phosphorylation pathway (p<0.05). The present study suggests that CPA significantly alters the functions and proteome content of spermatozoa. Additionally, we anticipated that the differentially expressed proteins might consider as biomarker of CPA-induced stress.