• 대한금속재료학회지
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• 제49권8호
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• pp.628-634
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• 2011

SA508 Gr.4N Ni-Cr-Mo low alloy steel, in which Ni and Cr contents are higher than in commercial SA508 Gr.3 Mn-Mo-Ni low alloy steels, may be a candidate reactor pressure vessel (RPV) material with higher strength and toughness from its tempered martensitic microstructure. The inner surface of the RPV is weld-cladded with stainless steels to prevent corrosion. The goal of this study is to evaluate the microstructural properties of the clad interface between Ni-Cr-Mo low alloy steel and stainless weldment, and the effects of post weld heat treatment (PWHT) on the properties. The properties of the clad interface were compared with those of commercial Mn-Mo-Ni low alloy steel. Multi-layer welding of model alloys with ER308L and ER309L stainless steel by the SAW method was performed, and then PWHT was conducted at $610^{\circ}C$ for 30 h. The microstructural changes of the clad interface were analyzed using OM, SEM and TEM, and micro-Vickers hardness tests were performed. Before PWHT, the heat affected zone (HAZ) showed higher hardness than base and weld metals due to formation of martensite after welding in both steels. In addition, the hardness of the HAZ in Ni-Cr-Mo low alloy steel was higher than that in Mn-Mo-Ni low alloy steel due to a comparatively high martensite fraction. The hardness of the HAZ decreased after PWHT in both steels, but the dark region was formed near the fusion line in which the hardness was locally high. In the case of Mn-Mo-Ni low alloy steel, formation of fine Cr-carbides in the weld region near the fusion line by diffusion of C from the base metal resulted in locally high hardness in the dark region. However, the precipitates of the region in the Ni-Cr-Mo low alloy steel were similar to that in the base metal, and the hardness in the region was not greatly different from that in the base metal.

• Journal of Applied Biological Chemistry
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• 제64권2호
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• pp.177-184
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• 2021

축산용 항생제는 투여된 양의 일부만이 체내에서 사용되며 나머지는 분뇨로 배출되며 이를 활용한 퇴비를 농경지에 살포함으로써 농업환경에 유입되어 2차 오염 등을 초래하고 있다. 따라서, 농업환경 중 항생제 관리기준 설정 등 사후 관리 기술이 필요하다. 본 연구는 국내 사용빈도가 높은 것으로 알려진 tetracycline 및 sulfonamide 계열 등의 항생제를 대상으로 매체별 잔류량을 비교하고 퇴비 시용 전·후 농경지 토양 중 잔류항생제의 위해성을 평가하기 위하여 수행되었다. Buffer 및 SPE를 사용한 전처리 방법은 ppb 수준에서 70% 이상의 회수율을 나타냈으며, 검출한계(LOD)의 범위는 퇴비와 토양에서 각각 0.13-0.46 ㎍/kg과 0.05-0.25 ㎍/kg이었다. 잔류 항생제 분석결과 퇴비 중 tetracycline 계열 항생제의 잔류 농도는 5.38-196.0 ㎍/kg, sulfonamide 계열은 below the detection of limit (BDL)-259.0 ㎍/kg 수준으로 검출되었다. 농경지 토양의 경우 각각 0.30-53.3 ㎍/kg, BDL-4.16 ㎍/kg의 잔류 수준을 나타냈으며 토양분배계수(Kd) 값이 높은 tetracycline 계열 항생제의 잔류 농도가 sulfonamide 계열보다 높았다. 퇴비 시용 전후의 농경지 토양의 항생제에 대한 인체위해도는 항생제 종류에 따른 차이가 있었으나, 전체 HQ가 1 이하에서 안전하다는 기준에 의하면 조사된 항생제 5종 모두 인체 위해성이 매우 낮았으며 시용 전·후의 영향이 전체 위해도에 미치는 비율을 고려하면, 퇴비시용이 토양의 항생제에 대한 인체위해성에 미치는 영향은 미비한 것으로 판단되었다.

• 한국콘텐츠학회논문지
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• 제21권6호
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• pp.327-335
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• 2021

본 연구는 치료도우미견을 활용한 동물매개치료가 아동의 자아존중감과 또래 관계에 어떠한 영향을 미치는지 살펴보고자 하였다. 연구대상은 I 시에 위치한 초등학교 저학년 아동 중 학교 사회복지사와 담임선생님의 추천을 받은 아동 20명이며, 실험집단 10명과 통제집단 10명을 선정하였다. 프로그램은 2019년 10월 1부터 12월 17일까지 동물매개치료 프로그램을 주 1회, 50분, 총 12회기를 실시하였다. 효과 검증을 위해 SPSS 20.0을 활용하여 실험집단과 통제집단에게 사전과 사후에 자아존중감, 또래관계 평정척도 측정을 실시하고 분석 하였다. 그 결과 첫째, 실험집단의 자아존중감 전체(Z=-2.75, p<.05), 가정에서의 자아존중감(Z=-2.02, p<.05), 학업적 자아존중감(Z=-2.06, p<.05)에서는 통계적으로 유의한 차이가 나타났다. 둘째, 실험집단의 또래관계 전체(Z=-3.83, p<.05), 하위 영역별로 주도성(Z=-2.68, p<.05), 협동공감(Z=-2.81, p<.05)에 유의미한 차이가 나타났다. 따라서 본 연구는 치료도우미견을 활용한 동물매개치료가 아동의 자아존중감과 또래관계에 긍정적인 영향을 준 것으로 확인이 되었다.

• 해양환경안전학회지
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• 제28권2호
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• pp.324-333
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• 2022

코로나19 는 전세계인의 일상을 안정적으로 유지하기 위하여 자신의 업무를 수행하고 있는 필수업무종사자에 대한 중요성을 다시 한번 각인시켜 주었다. 이와 관련하여 국제기구 및 주요 해외국가들은 선원을 필수업무종사자로 지정하고, 선원의 역할을 수행할 수 있도록 이들을 보호하는 각종 개선안을 권고하였다. 특히 국제해사기구는 선원의 원활한 승·하선 등을 지원해 줄 것을 관련 단체 및 회원국 등을 중심으로 촉구하고 있지만, 일부 국가들은 극단적인 자국우선주의로 인해 선원의 승·하선, 상륙, 병원진료 등을 제한하는 사례가 발생하고 있다. 이 연구는 코로나19에도 불구하고 글로벌공급망의 안전을 담당하고 있는 선원의 역할과 보호의 필요성에 대한 논리적 근거를 마련하기 위하여 국제기구 및 주요 해외 국가의 사례를 중심으로 비교하여 분석하였다. 이 연구는 해운산업에서 필수업무종사자로서 선원의 역할과 보호의 필요성을 확인하였고, 해운산업의 회복력을 강화하는 차원에서 선원의 처우 및 복지향상을 위한 시사점의 도출 및 법제도적인 개선방안을 제시하였다. 향후 이 연구는 선원의 역할과 보호의 필요성이 국가정책에 반영될 수 있도록 하는 기초자료서 역할을 할 것으로 기대된다.

• Journal of Gastric Cancer
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• 제22권2호
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• pp.94-106
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• 2022

Purpose: Laparoscopic proximal gastrectomy with double-tract reconstruction (LPG-DTR) is a function-preserving procedure performed for treating upper early gastric cancer (EGC). However, few studies have compared the outcomes of LPG-DTR with those of laparoscopic total gastrectomy (LTG). This study aimed at comparing the short-term outcomes of LPG-DTR between LTG and upper EGC. Materials and Methods: For upper-third EGC, a multicenter, prospective, randomized trial was performed to compare those who underwent LPG-DTR with those who underwent LTG. Short-term outcomes, including clinicopathologic results, morbidity, mortality, and postoperative courses, were evaluated using a full analysis set based on the intention-to-treat principle and the per-protocol set. Results: Of the patients, 138 who fulfilled the criteria were randomized to each group. One patient in the LPG-DTR group withdrew consent. Sixty-eight patients underwent LPG-DTR and 69 underwent LTG. The operative time (LPG-DTR=219.4 minutes; LTG=201.8 minutes; P=0.085), estimated blood loss (LPG-DTR=76.0 mL; LTG=66.1 mL; P=0.413), and the morbidity rate (LPG-DTR=23.5%; LTG=17.4%; P=0.373) between the groups were not significantly different. No mortality occurred in either of the study groups. Two weeks post operation, the Visick scores for postprandial symptoms, including reflux symptoms, were not significantly different between the groups (P=0.749). Laboratory findings on postoperative day 5 were not significantly different between the groups. Conclusions: The short-term outcomes of LPG-DTR for upper EGC were comparable to those of LTG.

• Molecules and Cells
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• 제45권7호
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• pp.465-478
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• 2022

MicroRNAs (miRNAs) are a class of small non-coding RNAs that regulate the expression of target messenger RNA (mRNA) complementary to the 3' untranslated region (UTR) at the post-transcriptional level. Hsa-miR-422a, which is commonly known as miRNA derived from transposable element (MDTE), was derived from short interspersed nuclear element (SINE). Through expression analysis, hsa-miR-422a was found to be highly expressed in both the small intestine and liver of crab-eating monkey. AT-Rich Interaction Domain 5 B (ARID5B) was selected as the target gene of hsa-miR-422a, which has two binding sites in both the exon and 3'UTR of ARID5B. To identify the interaction between hsa-miR-422a and ARID5B, a dual luciferase assay was conducted in HepG2 cell line. The luciferase activity of cells treated with the hsa-miR-422a mimic was upregulated and inversely downregulated when both the hsa-miR-422a mimic and inhibitor were administered. Nuclear factor erythroid-2 (NF-E2) was selected as the core transcription factor (TF) via feed forward loop analysis. The luciferase expression was downregulated when both the hsa-miR-422a mimic and siRNA of NF-E2 were treated, compared to the treatment of the hsa-miR-422a mimic alone. The present study suggests that hsa-miR-422a derived from SINE could bind to the exon region as well as the 3'UTR of ARID5B. Additionally, hsa-miR-422a was found to share binding sites in ARID5B with several TFs, including NF-E2. The hsa-miR-422a might thus interact with TF to regulate the expression of ARID5B, as demonstrated experimentally. Altogether, hsa-miR-422a acts as a super enhancer miRNA of ARID5B by collaborating with TF and NF-E2.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• 제24권3호
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• pp.288-294
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• 2021

Purpose: Despite aggressive medical and nutritional management, patients with methylmalonic acidemia (MMA) often suffer from multi-organ damage. Early deceased donor liver transplantation (DDLT) has emerged as an intervention to prevent disease progression. We investigated the efficacy of living donor LT (LDLT) with a potential carrier of MMA and a small volume of graft in patients with MMA as an alternative to DDLT. Methods: Of five patients (three male, two female; median age 5.7 years; range, 1.3-13.7 years), four underwent carrier LDLT, while one underwent non-carrier auxiliary LDLT. All patients received pre- and post-LT continuous renal replacement therapy and were provided with minimal restriction diet according to serum MMA level after LT. MMA levels in the serum and urine, the incidence of metabolic crisis, and clinical findings before and after LT were compared. Results: The survival rate was 100% during 2.2 years of follow up period after LT. In all five cases, MMA titer in the serum after transplantation decreased with less restrictive diet. Metabolic crisis was not observed during the follow-up period. In addition, no patient showed progression of severe renal impairment requiring hemodialysis. Progression of delayed cognitive development was not observed. Social functioning with improved neuropsychiatric development was observed. Conclusion: This study showed that LDLT achieved improved quality of life with less restrictive diet, therefore it could be a feasible alternative option to DDLT for the treatment of patients with MMA, even with an auxiliary LT.

• 대한본초학회지
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• 제34권2호
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• pp.41-47
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• 2019

Objectives : A traditional herbal prescription, Kyung-Ok-Ko (KOK), has long been used in oriental medicine as an invigorant for age-related diseases, such as amnesia and stroke. However, the beneficial value of KOK for immune responses is largely unknown. Based on the above mentioned effects of KOK, other previous reports, and its use in traditional medicine, we hypothesized that KOK displays beneficial effects against methotrexate (MTX)-induced immune suppression. Methods : We investigated the effects of KOK (0.6 g/kg/day, oral (p.o.)) on deteriorated immunity caused by MTX (2 mg/kg/day, p.o.) in an immune suppression mouse model. MTX was fed to mice once a day for 7 days. After the immune responses of the mice deteriorated by MTX treatment, KOK in water was fed to the mice once a day for 14 days. We then measured the expression levels of various cytokines, such as T helper cell (Th1, Th2) cytokines, and the number of immune cells, such as spleen T cells, B cells, and macrophages. Results : The data showed that MTX decreased Th1 profiles (interferon $(IFN)-{\gamma}$, interleukin (IL)-2, IL-12) and the number of immune cells, and increased Th2 profiles (IL-4, IL-5, IL-13), which were normalized significantly by post-administration of KOK. However, there was no significant difference in body-weight gain between MTX- and KOK-treated mice. Conclusion : These results indicate that KOK has immune-enhancing functions and reduces immunotoxicity of MTX, suggesting that supplementation with KOK will improve immune responses clinically and be useful for the prevention of immune-related diseases.

• 대한치과교정학회지
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• 제52권4호
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• pp.287-297
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• 2022

Objective: To investigate the pattern of accuracy change in artificial intelligence-assisted landmark identification (LI) using a convolutional neural network (CNN) algorithm in serial lateral cephalograms (Lat-cephs) of Class III (C-III) patients who underwent two-jaw orthognathic surgery. Methods: A total of 3,188 Lat-cephs of C-III patients were allocated into the training and validation sets (3,004 Lat-cephs of 751 patients) and test set (184 Lat-cephs of 46 patients; subdivided into the genioplasty and non-genioplasty groups, n = 23 per group) for LI. Each C-III patient in the test set had four Lat-cephs: initial (T0), pre-surgery (T1, presence of orthodontic brackets [OBs]), post-surgery (T2, presence of OBs and surgical plates and screws [S-PS]), and debonding (T3, presence of S-PS and fixed retainers [FR]). After mean errors of 20 landmarks between human gold standard and the CNN model were calculated, statistical analysis was performed. Results: The total mean error was 1.17 mm without significant difference among the four time-points (T0, 1.20 mm; T1, 1.14 mm; T2, 1.18 mm; T3, 1.15 mm). In comparison of two time-points ([T0, T1] vs. [T2, T3]), ANS, A point, and B point showed an increase in error (p < 0.01, 0.05, 0.01, respectively), while Mx6D and Md6D showeda decrease in error (all p < 0.01). No difference in errors existed at B point, Pogonion, Menton, Md1C, and Md1R between the genioplasty and non-genioplasty groups. Conclusions: The CNN model can be used for LI in serial Lat-cephs despite the presence of OB, S-PS, FR, genioplasty, and bone remodeling.

• 인간식물환경학회지
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• 제23권3호
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• pp.305-320
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• 2020

Background and objective: The problem that follows the increase of dementia patients is the burden of caregivers caring for dementia patients. The purpose of this study was to examine the effects of horticultural therapy programs improving the quality of life and reducing the depression and burden of caregivers of the elderly with dementia. Methods: In this study, 19 caregivers of the elderly with dementia were selected, and the experiment was conducted by dividing the control group (n=9) and the experimental group (n=10) by random distribution. The experimental group was given eight horticultural therapy programs twice a week for a total of 4 weeks. Subjects were assessed using the depression(CES-D), quality of Life (WHOQOL-BREF), and care burden scales. The evaluation results were verified at a 95% significance level using descriptive statistics, the Mann-Whitney U test, and Wilcoxon signed-rank test. Results: In the case of depression, the control group's score tended to increase, and the experimental group's score appeared to decrease, but it was not a statistically significant change. In the quality of life, the control group was not statistically significant, but scores decreased overall. On the other hand, in the experimental group, the general quality of life increased significantly from 11.60 to 14.20 points (p = .02), and the total quality of life increased to a marginally significant level from 61.59 points to 68.85 points (p = .059). In the post-test of the total care burden score, a marginally significant difference was found between the control group (94.44 points) and the experimental group (82.50 points; p = .079). Conclusion: This study confirmed the applicability to reduce the burden of caregiving and improve the deterioration of quality of life of the caregivers. In particular, the results will serve as an opportunity to confirm accessibility in a new way to support the caregiver of dementia patients by demonstrating the applicability of horticultural therapy at a time when problems such as the burden of supporting the caregiver are emerging as social problems.