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차량용 전동 액추에이터 기어박스의 작동소음 저감을 위한 기초 연구
김찬호(Chanho Kim),서대관(Daekwan Seo),신헌철(Heoncheol Shin),이정인(JunginLee) 한국자동차공학회 2017 한국자동차공학회 학술대회 및 전시회 Vol.2017 No.11
Recently, automotive industry is facing changes in a new trend of technology such as eco-friendly, high efficiency and autonomous driving car, and have been overcoming through substitution of internal combustion engine over electric motors. To come up with, automotive parts which are depend on internal combustion engine power has been changed into electric motors and gearbox combinations, and controlling its operating noise is getting more important to satisfy customers’ emotional needs. Through this study, the basic research about operating noise control for an automotive-applied motor driven actuator was performed by analyzing its operating noise with every steps of operating modes. As a result of analysis for each mode, noise and vibration increased at specific rpm of drive motor. As a comparison between noise source and the results of modal test of the system, operating frequency and resonance frequency of the system were overlapped. To solve this problem, several steps of design changing were performed such as changing the shape of gearbox’s cover and the shape of the rubber seal. The results of the steps were defined, and the most effective step was derived.
Sex hormones establish a reserve pool of adult muscle stem cells
Kim, Ji-Hoon,Han, Gi-Chan,Seo, Ji-Yun,Park, Inkuk,Park, Wookjin,Jeong, Hyun-Woo,Lee, Su Hyeon,Bae, Sung-hwan,Seong, Jinwoo,Yum, Min-Kyu,Hann, Sang-Hyeon,Kwon, Young-Guen,Seo, Daekwan,Choi, Man ,Ho Nature Publishing Group 2016 NATURE CELL BIOLOGY Vol. No.
<P>Quiescent satellite cells, known as adult muscle stem cells, possess a remarkable ability to regenerate skeletal muscle following injury throughout life. Although they mainly originate from multipotent stem/progenitor cells of the somite, the mechanism underlying the establishment of quiescent satellite cell populations is unknown. Here, we show that sex hormones induce Mind bomb 1 (Mib1) expression in myofibres at puberty, which activates Notch signalling in cycling juvenile satellite cells and causes them to be converted into adult quiescent satellite cells. Myofibres lacking Mib1 fail to send Notch signals to juvenile satellite cells, leading to impaired cell cycle exit and depletion. Our findings reveal that the hypothalamic-pituitary-gonadal axis drives Mibi expression in the myofibre niche. Moreover, the same axis regulates the re-establishment of quiescent satellite cell populations following injury. Our data show that sex hormones establish adult quiescent satellite cell populations by regulating the myofibre niche at puberty and re-establish them during regeneration.</P>
Is routine nasogastric tube insertion necessary in pancreaticoduodenectomy?
Yoon Young Choi,Jungman Kim,Daekwan Seo,Dongho Choi,Min Joo Kim,Jung Hoon Kim,Kyung-Jae Lee,Kyung Yul Hur 대한외과학회 2011 Annals of Surgical Treatment and Research(ASRT) Vol.81 No.4
Purpose: The necessity of nasogastric decompression after abdominal surgical procedures has been increasingly questioned for several years. Traditionally, nasogastric decompression is a mandatory procedure after classical pancreaticoduodenectomy (PD); however, we still do not know whether or not it is necessary for PD. The present study was designed to assess the clinical benefit of nasogastric decompression after PD. Methods: Between July 2004 and May 2007, 41 consecutive patients who underwent PD were enrolled in this study. Eighteen patients were enrolled in the nasogastric tube (NGT) group and 23 patients were enrolled in the no NGT group. Results: There were no differences in the demographics, pathology, co-morbid medical conditions, and pre-operative laboratory values between the two groups. In addition, the passage of flatus (P = 0.963) and starting time of oral intake (P = 0.951) were similar in both groups. In the NGT group, 61% of the patients complained of discomfort related to the NGT. Pleural effusions were frequent in the NGT group (P = 0.037); however, other post-operative complications, such as wound dehiscence and anastomotic leakage, occurred similarly in both groups. There was one case of NGT re-insertion in the NGT group. Conclusion: Routine nasogastric decompression in patients undergoing PD is not mandatory because it has no clinical advantages and increases patient discomfort.
이수이,권혁찬,김성현,오성용,Ji Hyun Lee,이연수,Daekwan Seo,한진영,김효진 대한혈액학회 2012 Blood Research Vol.47 No.3
Background Myelodysplastic syndrome (MDS) is a preleukemic condition that transforms into acute myeloid leukemia. However, the genetic events underlying this transformation remain poorly understood. Aberrant DNA methylation may play a causative role in the disease and its prognosis. Thus, we compared the DNA methylation profiles in refractory anemia with excess blast (RAEB) to those in refractory cytopenia with multilineage dysplasia (RCMD). Methods Bone marrow samples were collected from 20 patients with primary MDS (9 with RAEB and 11 with RCMD), and peripheral blood samples were collected from 4 healthy controls. These samples were assessed using a commercial whole genome-wide methylation assay. Methylation-specific polymerase chain reaction (PCR) was used to detect the methylation of candidate gene promoters in RAEB and RCMD. Results Microarray data revealed significant hypermethylation in 69 genes within RAEB but not RCMD. Candidate genes were mapped to 5 different networks, and network 1 had the highest score due to its involvement in gene expression, cancer, and cell cycle. Five genes (GSTM5, BIK, CENPH, RERG, and ANGPTL2) were associated with malignant disease progression. Among them, the methylated promoter pairs of GSTM5 (55.5% and 20%), BIK (20% and 0%), and ANGPTL2 (44.4% and 10%) were observed more frequently in RAEB. Conclusion DNA methylation of GSTM5, BIK, and ANGPTL2 may induce epigenetic silencing and contribute to the increasing blasts and resulting MDS progression; however, the functions of these genes were not determined. Further study focusing on epigenetic silencing using various detection modalities is required.