NR과 SBR 가황물의 경도와 강성도에 대한 온도의 영향

진현호 ( Hyun Ho Jin ),홍창국 ( Chang Kook Hong ),조동련 ( Dong Lyun Cho ),강신영 ( Shin Young Kaang ) 한국고무학회 2007 엘라스토머 및 콤포지트 Vol.42 No.3

본 연구에서는 고무제품의 수치 안정성과 성능유지에 직접적으로 영향을 미치는 중요한 특성 중 하나인 온도변화에 따른 고무재료의 경도변화를 고찰하였다. 새롭게 제작된 International Rubber Hardness Degree(IRHD, Normal type) 경도측정 시험기를 사용하여 미충전된 NR과 SBR시편의 여러 온도에서 경도변화를 측정하였으며 Young`s modulus 값과 비교하였다. NR과 SBR 모두 유리전이온도 근처에서 경도와 Young`s modulus의 급격한 변화를 보였다. 온도가 증가함에 따라 경도와 Young`s modulus 값이 증가하는 경향을 보였으며 이는 분자의 운동성과 엔트로피 영향으로 해석할 수 있다. 카본블랙과 실리카가 충전된 NR과 SBR의 경우 충전제의 함량이 증가함에 따라 경도에 미치는 온도의 영향이 감소함을 관찰하였다. Hardness of rubbery materials, which is important for dimensional stability and product performance, was investigated upon temperature change in this study. A newly developed IRHD (International Rubber Hardness Degree) tester was used to measure the hardness changes of NR and SBR specimens at various temperatures and the hardness values were compared with the Young`s modulus. The hardness and Young`s modulus of NR and SBR showed an abrupt change near the glass transition temperatures. The hardness and Young`s modulus were increased by increasing temperature due to the increased random chain conformation of molecules. The effect of temperature on hardness and Young`s modulus of NR and SBR specimens filled with carbon black and silica was decreased by increasing filler content.

만성 화농성 중이염의 세균학적 고찰

조남순,이영훈,강기훈,최제환,송태현,이병돈,장혁순,강주원,김연준 순천향의학연구소;Soonchunhyang Medical Research Institute 2000 Journal of Soonchunhyang Medical Science Vol.6 No.1

Background and Objectives : Chronic suppurative otitis media is one of the frequent diseases in otolaryngologic field. It is important to choose of antibiotics in the management of infectious disease. But the organisms in infections have been changed and resistance to antibiotics has been grown as the development of antibiotics has been achieved. And so it has been necessary to recognize the changes of organisms and resistance in antibiotics. Our study was performed to identify the pathogens isolated from discharges in chronic otitis media and evaluate the antibiotic agents, to recognize the change of to resistance to·antibiotic agents and to use the appropriate anitiotics. Materials and Methods : Retrospectively, authors reviewed the backeriologic study of 114 cases of chronic suppurative otitis media who visited the Department of Otolaryngology, Soonchunhyang University in Seoul from Nov. 1996 to Oct. 1999 and analyzed 101 strains and its sensitivity test to various antibiotics. Result : In 93 cases in which pathogenic organism was isolated, single infection was 85 cases(91.4%) and mixed infection was 8 cases(8.6%). The most frequent pathogenic organism was Staphylococcus aureus(59.4%), Pseudomonas aeruginosa(13.9%), Providencia(4.8%), Alcaligenes(3.0%) and Streptococcus pneumoniae(2.9%) were the next. Methicilline-Resistance Staphylococcus aureus was 34 cases(57.6%) of Staphylococcus aureus. Staphylococcus aureus was sensitive to Vancomycin(96.7%), Trimethoprim-Sulfamethoxazole (57.6%), Cefuroxime(42.4%) and Ciprofloxacin(40.7%) but resistant to Penicillin(94.9%). Pseudomonas aeruginosa was sentitive Amikacin(100%), Ciprofloxacin(100%) and Gentamicin(67%). Conclusion : As MRSA recently was wide spread in community accquired infection as well as nosocomial infection, we must consider strict control of MRSA.

18–30세 사이에 발생하는 뇌경색의 특징, 다기관 레지스트리 연구

장윤경,송태진,김용재,허지회,이경열,김영은,장민욱,조수진,강석윤 이화여자대학교 의과학연구소 2017 EMJ (Ewha medical journal) Vol.40 No.3

Objectives: Although there have been several reports that described characteristics for young age stroke, information regarding very young age (18–30 years old) has been limited. We aimed to analyze demographic factors, stroke subtype, and 3-month outcome in acute ischemic stroke patient who have relatively very young age in multicenter stroke registry. Methods: We evaluated all 122 (7.1%) consecutive acute ischemic stroke (within 7 days after symptom onset) patients aged 18 to 30 from 17,144 patients who registered in multicenter prospective stroke registry, 1997 to 2012. Etiology was classified by Trial of Org 10172 in Acute Stroke Treatment criteria. Stroke severity was defined as National Institutes of Health Stroke Scale (NIHSS) and stroke outcome was defined by modified Rankin scale (mRS) at 3 months after index stroke. Results: The mean age of all included patients was 25.1±3.7 years and 76 patients (62.2%) were male. The median NIHSS at admission was 4. Considering stroke subtype, 37 patients (30.3%) had stroke of other determined etiology (SOD), 37 (30.3%) had undetermined negative evaluation (UN) and 31 (25.4%) had cardioembolism (CE) were frequently noted. After adjusting age, sex and variables which had P<0.1 in univariable analysis (NIHSS and stroke subtype), CE stroke subtype (odds ratio, 4.68; 95% confidence interval, 1.42–15.48; P=0.011) were significantly associated with poor functional outcome (mRS≥3). Conclusion: In very young age ischemic stroke patients, SOD and UN stroke subtype were most common and CE stroke subtype was independently associated with poor discharge outcome.

무증상 갑상선기능저하증 환자에서 Thyroxine 치료에 따른 혈청 지질 및 아포지단백의 변화

조보연,신찬수,김원배,고창순,김성연,박혜영,박건상,이홍규,박형규,김숙경 대한내분비학회 1996 Endocrinology and metabolism Vol.11 No.1

Background: Subclinical hypothyroidism(SCH) is a common biochemical abnormality which can be found in routine screening tests of thyroid function. We are increasingly faced with the question of whether its an indication for thyroxine replacement therapy. The effect of thyroxine replacement on lipid profile in SCH has aroused a great interest because of an association of overt hypothyroidism(OVH) with hyperlipidemia and increased risk of coronary artery disease. Method: We prospectively evaluated the changes in lipids and apoproteins before and after thyroxine replacement therapy in 23 patients with SCH and in 37 patients with OVH. We measured serum total cholesterol and triglyceride using autoanalyzer, high density lipoprotein(HDL) chole-sterol by dextran sulfate method, Apo A1 and Apo B by immunonephelometric assay. Results: Thyroxine replacement therapy significantly decreased total cholesterol, low density lipoprotein(LDL) cholesterol and apo B levels, but did not affect the level of triglyceride, HDL cholesterol or apo AI in patients with OVH. In SCH, thyroxine replacement therapy with the doses to normalize serum TSH concentrations also decreased significantly the level of cholesterol and LDL cholesterol albeit apo B levels did not change. Moreover, in most of patients with OVH (11 of 12) and in all of patients with SCH(5 of 5) who had had hyperchlesterolemia before treatment, thyroxine replament normalized their cholesterol and LDL cholesterol levels. Conclusion: In regard to the beneficial changes in blood lipid levels, patients with SCH should be treated, especially in cases who have other risk factors for the development of atherosclerosis. If thyroxine replacement only will reduce the incidence of coronary artery disease in SCH remains to be elucidated by long-term prospective studies(J Kor Soc Endocrinol 11:41-51, 1996).

야뇨증 환아들의 심리사회적 특성에 대한 다기관 연구 : 행동 및 정서 문제를 중심으로

조수철,김재원,신민섭,황준원,한상원,박관현,이상돈,김경도,김건석,서홍진,이유식,정재용,김영균,문두건,남궁미경,한창희,조원열,김영식,배기수,이종국,정우영,신의진 大韓神經精神醫學會 2005 신경정신의학 Vol.44 No.6

Objectives : The aim of this study was to examine the behavioral and emotional problems associated with nocturnal enuresis in Korean children. Methods : Three hundred eighteen children with nocturnal enuresis, together with their parents, completed the Child Behavior Checklist (CBCL), Disruptive Behavior Disorder Scale according to DSM-IV (DBDS), Children's Depression Inventory (CDI), State-Trait Anxiety Inventory for Children (STAIC), and Piers-Harris Children's Self-Concept Scale (PHCSC). Ninety-three normal students were selected as the control group. Results : Compared to the normal control group, the mean scores with regard to the withdrawn, social problems, attention problems, delinquent behavior, aggressive behavior, externalizing problems and total problems profiles were significantly higher in the nocturnal enuresis group according to the CBCL results. The nocturnal enuresis group also scored significantly higher in the ADHD and ODD profiles of the DBDS. The nocturnal enuresis group was more depressed and anxious than the control group according to the results of the CDI and STAI. The mean score of the PHCSC was significantly lower in the nocturnal enuresis group when compared to the normal control group. Conclusion : The results of this study suggest that children with nocturnal enuresis in Korea have clinically relevant behavioral and emotional problems. The findings support the link between nocturnal enuresis and psychopathology in Korean children.

Minimize makespan of permutation flowshop using pointer network

Cho Young In,Nam So Hyun,Cho Ki Young,Yoon Hee Chang,Woo Jong Hun 한국CDE학회 2022 Journal of computational design and engineering Vol.9 No.1

During the shipbuilding process, a block assembly line suffers a bottleneck when the largest amount of material is processed. Therefore, scheduling optimization is important for the productivity. Currently, sequence of inbound products is controlled by determining the input sequence using a heuristic or metaheuristic approach. However, the metaheuristic algorithm has limitations in that the computation time increases exponentially as the number of input objects increases, and separate optimization calculations are required for every problem. Also, the heuristic such as dispatching algorithm has the limitation of the exploring the problem domain. Therefore, this study tries a reinforcement learning algorithm based on a pointer network to overcome these limitations. Reinforcement learning with pointer network is found to be suitable for permutation flowshop problem, including input-order optimization. A trained neural network is applied without re-learning, even if the number of inputs is changed. The trained model shows the meaningful results compared with the heuristic and metaheuristic algorithms in makespan and computation time. The trained model outperforms the heuristic and metaheuristic algorithms within a limited range of permutation flowshop problem.

흡연자와 비흡연자사이에서의 비과민성 반응의 차이

김영도,조중생,장도영,홍남표,차창일 대한이비인후과학회 1998 대한이비인후과학회지 두경부외과학 Vol.41 No.9

Clinical application of shear wave elastography (SWE) in the diagnosis of benign and malignant breast diseases.

Chang, Jung Min,Moon, Woo Kyung,Cho, Nariya,Yi, Ann,Koo, Hye Ryoung,Han, Wonsik,Noh, Dong-Young,Moon, Hyeong-Gon,Kim, Seung Ja M. Nijhoff ; Kluwer Academic Publishers 2011 Breast cancer research and treatment Vol.129 No.1

<P>Shear wave elastography (SWE) is an emerging technique which can obtain quantitative elasticity values in breast disease. We therefore evaluated the diagnostic performance of SWE for the differentiation of breast masses compared with conventional ultrasound (US). Conventional US and SWE were performed by three experienced radiologists for 158 consecutive women who had been scheduled for US-guided core biopsy or surgical excision in 182 breast masses (89 malignancies and 93 benign; mean size, 1.76??cm). For each lesion, quantitative elasticity was measured in terms of the Young's modulus (in kilopascals, kPa) with SWE, and BI-RADS final categories were assessed with conventional US. The mean elasticity values were significantly higher in malignant masses (153.3??kPa??±??58.1) than in benign masses (46.1??kPa??±??42.9), (P??<??0.0001). The average mean elasticity values of invasive ductal (157.5??±??57.07) or invasive lobular (169.5??±??61.06) carcinomas were higher than those of ductal carcinoma in situ (117.8??kPa??±??54.72). The average mean value was 49.58??±??43.51 for fibroadenoma, 35.3??±??31.2 for fibrocystic changes, 69.5??±??63.2 for intraductal papilloma, and 149.5??±??132.4 for adenosis or stromal fibrosis. The optimal cut-off value, yielding the maximal sum of sensitivity and specificity, was 80.17??kPa, and the sensitivity and specificity of SWE were 88.8% (79 of 89) and 84.9% (79 of 93). The area under the ROC curve (Az value) was 0.898 for conventional US, 0.932 for SWE, and 0.982 for combined data. In conclusion, there were significant differences in the elasticity values of benign and malignant masses as well as invasive and intraductal cancers with SWE. Our results suggest that SWE has the potential to aid in the differentiation of benign and malignant breast lesions.</P>

알코올에 의한 α-Tocopherol이 혈액성분에 미치는 영향

김영순,이상한,김창세,조만희 순천향의학연구소 1995 Journal of Soonchunhyang Medical Science Vol.1 No.2

This study was done in order to observe the effects of ethanol and a-tocopherol on the serum ALP, BUN and uric acid concentrations. The white Sprague-Dawley rats were classified with 4-grops : 0.9% NaCl administration was group A control, 25% ethanol administration for the each 5, 10 and 15 days was group B(Bl, B2 and B3), 25% ethanol administration for the each 5, 10 and 15 days and 50% a-tocopherol for the 2 and 7 days administration was group C (Cl and C2) and 50% a-tocopherol pretreated for the each 5, 10 and 16 days and 25% ethanol for the 2, 7 and the 10 days administration was group D(Dl, D2 and D3) The following results were obtained. 1. The changes of serum ALP activity was significantly increased in ethanol treated group. The group C and D was decreased. 2. The changes of serum BUN concentration between each group were not significant and however B2, B3, C2 and Dl was significantly increased. 3. The changes of serum uric acid concentration between each group were not significant. However group Cl and Dl was slightly decreased patterns.

LC, Acute : O-061 ; Mode of cirrhosis related complication in Korean patients with liver cirrhosis -A prospective multicenter cohort study

( Hyun Young Woo ),( Jeong Won Jang ),( Sang Gyune Kim ),( Chang Hyeong Lee ),( Tae Yeob Kim ),( Won Young Tak ),( Sung Kyu Choi ),( Mong Cho1 ),( Jong Young Choi ) 대한간학회 2012 춘·추계 학술대회 (KASL) Vol.2012 No.-

Background: Cirrhosis-related complications are indications for transplantation. However, the mode of complication has not been evaluated so far. To better address this issue, we investigated the mode of cirrhosis related complication and impact of these complications on survival in prospective, multicenter, inception cohort study of subjects with liver cirrhosis presenting with the first onset of decompensated complication. Methods: In this observational study, 1515 patients with the confirmed onset time of the first decompensated complication were enrolled. The mortality risk of cirrhosis-related complications, including ascites, portal hypertensive gastrointestinal bleeding (PHGB), spontaneous bacterial peritonitis (SBP), hepatic encephalopathy (HE), hepatorenal syndrome (HRS), was analyzed in these cirrhotic patients. Result: As the first complication, ascites was the most frequent (53.8%), followed PHGB (36.2%), HE (7.6%), SBP (1.7%) and HRS (0.7%). During follow-up (mean 32±47 months), 484 (31.9%) experienced subsequent decompensations and the proportion of subsequent complication was consistently changed; the proportion of HE, SBP, HRS increased as time progressed. The interval between subsequent decompensative events was progressively shortened. The mortality rate according to the first complication was as follows; Ascites =PHGB> HE=SBP>HRS. The mortality rate of patients experienceing subsequent complication was significantly higher than those without subsequent complication. According to the kinds of subsequent complication, survival of HE was also higher than HRS but lower than ascites or PHGB and similar to that of SBP and this difference of survival disappeared after repeated complication. Conclusion: The mortality risk correlated with initial complication and the risk increases as the number of complication episodes is repeated. Patient`s mean age was 56±11.50 years and 72.1% was male. The cause of liver cirrhosis is hepatitis B virus (38.6%), alcohol (35.5%) and hepatitis C virus (8.9%).