• Title/Summary/Keyword: 혈액 유동

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Development and Evaluation of RANS based Turbulence Model for Viscoelastic Fluid (점탄성 유체해석용 RANS 기반 난류 모델 개발 및 검증)

  • Ro, Kyoung-Chul
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.18 no.3
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    • pp.545-550
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    • 2017
  • When the systolic blood pressure is high, intermittent turbulence in blood flow appears in the aorta and carotid artery with stenosis during the systolic period. The turbulent blood flow is difficult to analyze using the Newtonian turbulence model due to the viscous characteristics of blood flow. As the shear rate is increased, the blood viscosity decreases by the viscoelastic properties of blood and a drag reduction phenomenon occurs in turbulent blood flow. Therefore, a new non-Newtonian turbulent model is required for viscoelastic fluid and hemodynamics. The main aims of this study were to develop a non-Newtonian turbulence model using the drag reduction phenomenon based on the standard $k-{\varepsilon}$ turbulent model for a general non-Newtonian fluid. This was validated with the experimental data and has a good tendency for non-Newtonian turbulent flow. In addition, the computation time and resources were lower than those of the low Reynolds number turbulent model. A modified turbulent model was used to analyze various turbulent blood flows.

Rapid Regression of White Matter Changes in Hypoglycemic Encephalopathy (저혈당성 뇌병증에서 뇌백질 변화의 빠른 퇴행)

  • Son, Sang-Wook;Lee, Kye-Ho;Yoo, Dong-Soo
    • Investigative Magnetic Resonance Imaging
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    • v.18 no.4
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    • pp.357-361
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    • 2014
  • Purpose : In a previous report, it took several days for white matter lesions to regress in hypoglycemic encephalopathy. We present a case of rapid diffusion-weighted image (DWI) changes in hypoglycemic encephalopathy. Case Report: A 58-year-old male patient was found semi-comatous with the only abnormality in his laboratory tests showing hypoglycemia (44 mg/dL). After rapid correction of glucose level, immediate brain DWI showed bilateral subcortical white matter lesions. After about 5 hours, follow-up DWI showed resolved subcortical white matter lesions, with newly-appeared bilateral fronto-temporo-parietal cortical lesions. Conclusion: Both white matter and cortex involvement in hypoglycemic encephalopathy has been shown in several reports, but rapid regression of white matter changes in hypoglycemic encephalopathy has been rarely reported. It is important to know that MR imaging changes in hypoglycemic encephalopathy can be made as quick as just a few-hour-long.

Effect of Feeding Herb Extract on Growth Performance, Intestinal Microflora and Blood Component Profile in Broiler Chickens (한약재 추출물의 급여가 육계의 생산성, 장내 미생물 및 혈액 성상에 미치는 영향)

  • Park, S.B.;Na, J.C.;Yu, D.J.;Bang, H.T.;Hwang, I.H.;Ryu, K.S.
    • Korean Journal of Poultry Science
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    • v.35 no.1
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    • pp.79-84
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    • 2008
  • This study was conducted to investigate the effects of feeding herb extract (HE) on productivity, intestinal microflora and blood component profile in broiler chickens. A total of three hundred twenty, 1-d-old male chicks (Ross) were divided into 4 treatments with 5 replicates, 16 birds per replicate. Dietary treatments consisted of four diets; the corn-soybean based control diet, the diet containing HE 0.1%, the diet containing HE 0.2%, and the diet containing HE 0.4%. The Control diet contained 3,100, 3,100, 3,200 kcal/kg ME and 22%, 20%, 18% CP for starter ($0{\sim}2 wk$), grower ($3{\sim}5 wk$), and finisher ($6{\sim}7 wk$) periods, respectively. There were no significant differences in feed intake and BW gain among treatments in starter period. In grower period, the BW gain of HE 0.2%, and HE 0.4% were significantly higher (p<0.05) compared to Control. The 7-wk BW gain of HE 0.2% was significantly higher than Control (p<0.05). The feed intake tended to increase in HE 0.1%, but no difference was detected in feed conversion ratio among treatments. No significant differences were found in blood total cholesterol, triglyceride, HDL-cholesterol, glucose, total protein, and albumin among treatments, but total cholesterol in HE 0.4% decreased significantly as compared with Control. The cfu of Lactobacillus spp., yeast, and E. coli in the guts of chickens fed HE were not different form each other, but tended to increase as compared with Control.

Effect of Feeding Induced Molting on the Visceral Organs and Blood Component Profile in Laying Hens (비절식 강제 환우 방법이 산란계의 장기 비율과 혈액 성상에 미치는 영향)

  • Na, J.C.;Park, S.B.;Yu, D.J.;Bang, H.T.;Kim, S.H.;Kang, G.H.;Kim, H.K.;Choi, H.C.;HwangBo, J.;Kang, B.S.;Suh, O.S.;Jang, B.G.;Choi, J.T.
    • Korean Journal of Poultry Science
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    • v.35 no.4
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    • pp.375-380
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    • 2009
  • This study was conducted to investigate the effect of feeding induced molting on the visceral organs and blood component profile in laying hens and designed to test 400 flocks of 60 week old Leghorn laying hens for 34 weeks. A total of four molting treatment methods by including the molted with customary molting by fasting method (c), feeding single diet of corn (T1), feeding single diet of wheat bran (T2) and feeding single diet of alfalfa meal (T3) were tested, and each treatment was repeated for 5 times, and 20 laying hens were randomly assigned in an cage for each repeat. As the result of the experiment, ovary was $2.03{\sim}6%$ and oviduct was $2.51{\sim}3.47%$ in visceral organs for body weight at pre-molting term, but there was no significant difference. At post-molting, no significant difference was found, ovary was $0.25{\sim}0.41%$, uterus of control, T1, T2 and T3 was 1.12%, 0.82%, 0.48% and 0.90%, respectively. T2 was significantly lower than control, T3 (p<0.05) at the 50% of egg production. Ovary was $2.20{\sim}2.60%$ and oviduct was $2.98{\sim}3.45%$. In addition, ovary was $2.65{\sim}3.01%$, oviduct was $3.23{\sim}3.64%$ at the peak egg production, but there was no significant difference by non-feeding and feeding molting treatments. In blood component profile, cholesterol was $179.8{\sim}245.7\;mg/dL$ at pre-molting, but there was no significant difference and at post-molting, concentration of cholestrol in control, T1, T2 and T3 was 353.6, 229.1, 261.8 and 300.6 mg/dL, respectively. T1 was significantly lower than control and T3 (p<0.05). In addition, first laying day was $228.1{\sim}271.8\;mg/dL$, 50% of egg production was $236.5{\sim}284.8\;mg/dL$, there was no significant difference. Concentration of cholestrol in control, T1, T2 and T3 was 324.1, 591.6, 363.0 and 315.6 mg/dL, respectively, at the peak egg production period. T1 was significantly higher than other treatment (p<0.05).

Effect of Induced Molting on Changes of Visceral Organs and Blood Stress Indicators in Laying Hens (산란계의 유도 환우가 주요 장기와 혈액 성상의 변화에 미치는 영향)

  • Hong, E.C.;Park, H.D.;Kang, G.H.;Na, J.C.;You, D.C.;Kim, H.K.;Choi, Y.H.;Bae, H.D.;HwangBo, J.
    • Korean Journal of Poultry Science
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    • v.36 no.2
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    • pp.117-123
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    • 2009
  • This work was conducted to evaluate the effects of induced-molting methods on visceral organs and blood stress indicators in laying hens. One hundred fifty of 63-wk-old White Leghorn hens, with over 85% of egg production and $1.7\;{\pm}0.4\;kg$ of average weight, were used in this study. Treatments were control (non-molt treatment), feeding molt treatment (FM), and starving molt treatment (SM). There were 5 replicates of 10 hens for each treatment. All treatment groups were fed basal diet (15% CP and 2,700 kal/kg of ME) for two weeks as adaptation period. Heart weights were 8.2, 7.9 and 7.5 g in control, FM and SM, respectively. Liver and oviduct weights were decreased in both molting treatments compared with control (P<0.05). Corticosterone (CS) concentrations were 4.48, 4.47 and $4.66\;{\mu}g/mL$ in control, FM and SM at 61 weeks, respectively, but increased to 7.32, 7.11 and $7.71\;{\mu}g/mL$ at 62 weeks, respectively (P<0.05). Heterophil to lymphocyte ratios were 0.27~0.29 in all groups at 61 weeks, but increased to 0.97~1.03 in SM at 62 weeks. Both CS concentrations and H:L ratios in SM were greater compared with those for the other groups. These results suggest that hens in feeding molting program in hens are less stressed than those in starving molting one.

Effect of heat stress on growth performance and physiological changes of pigs in commercial farm (고온스트레스가 일반 양돈농가의 돼지 생산성 및 생리 변화에 미치는 영향)

  • Oh, Seo Young;Jeong, Yong Dae;Kim, Doo Wan;Min, Ye Jin;Yu, Dong Jo;Kim, Ki Hyun;Kim, Young Hwa
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.18 no.7
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    • pp.130-139
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    • 2017
  • This study investigated the effect of heat stress on the performance and blood characteristics in commercial pig farms. A total of 180 growing pigs and 180 finishing pigs were assigned to two treatments consisting of thermal-neutral period(TNP) and high-temperature period(HTP) with three replications in floor pen, respectively. Feeding trials in the TNP and HTP were individually performed in autumn and summer seasons, respectively. Temperature-humidity index(THI) was calculated by temperature and humidity. Performance and physiological responses were identified per growth stages and feeding trial. Average temperature and THI were $16.8^{\circ}C$ and 61.4 at the TNP, and $25^{\circ}C$ and 74.3 at the HTP, respectively. Growing pigs in HTP exhibited lower BW, ADG and ADFI than in TNP(p<0.01). Similarly, finishing pigs showed lower growth parameters in HTP than in TNP(p<0.01). Lymphocytes and neutrophils of growing pigs were lower in HTP than in TNP(p<0.05). The serum T-PRO and NEFA in finishing pigs were higher in HTP than in TNP(p<0.05). In HTP, finishing pigs had higher cortisol levels than in TNP. Therefore, HTP can negatively influence growth performance and nutritional metabolism in pigs. Our results may provide useful information for developing feeding programs and diets to control heat stress for swine farms.

Effects of Single or Mixed Supplements of Plant Extract, Fermented Medicinal Plants and Lactobacillus on Growth Performance in Broilers (식물 추출물, 한방 발효물, 유산균의 단독 및 혼합 첨가 급여가 육계 생산성에 미치는 영향)

  • Kim, D.W.;Kim, S.H.;Yu, D.J.;Kang, G.H.;Kim, J.H.;Kang, H.G.;Jang, B.G.;Na, J.C.;Suh, O.S.;Jang, I.S.;Lee, K.H.
    • Korean Journal of Poultry Science
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    • v.34 no.3
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    • pp.187-196
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    • 2007
  • This experiment was conducted to investigate the effect of dietary single or mixed supplementation of plant extract, fermented medicinal plants and Lactobacillus on performance, nutrient availability, blood characteristics, cecal microflora and intestinal digestive enzymes activity in broiler chickens and to prove the possibility of plant derived compounds and Lactobacillus as an antibiotic growth promoter alternative. A total of eight hundred forty, 1-d-old male broiler chicks (Ross strain) were randomly divided into 7 groups with 4 replicates of 30 birds each. The treatments were NC (antibiotic-free diet), PC (basal diet with 0.05% antibiotics and 0.03% anticoccidials), PE (basal diet with 0.1% plant extract), FMP (basal diet with 0.1% fermented medicinal plants), LB (basal diet with 0.1% probiotics), PE+LB (basal diet with 0.1% plant extract and 0.1% probiotics) and FMP+LB (basal diet with 0.1% fermented medicinal plants and 0.1% probiotics). The final body weight, body weight gain and feed conversion rate in all treated groups tended to be improved or significantly improved as compared to those of NC (P<0.05). PE was significantly high in the final body weight, body weight gain of all treated groups (P<0.05). But the growth performance was significantly lower in all treated groups except PE than PC (P<0.05). No synergic effect in growth performance was found when plant extracts and Lactobacillus were mixed and fed to broilers. The ratio of albumin to globulin was significantly lower in all groups than NC (P<0.05). And the stress indicator (lymphocyte/heterophil ratio) of NC was significantly reduced than other treatments (P<0.05). No significant differences were observed on the numbers of cecal microbes and Lactobacillus. The number of cecal E. coli and Salmonella in FMP and LB were significantly reduced (P<0.05). The activity of intestinal digestive enzymes except to sucrase of treated groups significantly decreased compare to those of controls (P<0.05). These results suggest the possibility that plant extracts and Lactobacillus could be used as the alternative of antibiotic growth promoters by improving the performance of broiler chicks.

Surgical removal of a left ventricular thrombus caused by acute myocarditis (급성 심근염에 의한 좌심실 혈전의 수술적 제거 1례)

  • Lee, Kyu Ha;Yoon, Min Jung;Han, Mi Young;Chung, Sa Jun;Kim, Soo Cheol
    • Clinical and Experimental Pediatrics
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    • v.50 no.6
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    • pp.588-591
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    • 2007
  • Left ventricular thrombus is mainly caused by anterior myocardial infarction or severe cardiac wall dysfunction of the apex, and is rarely caused by a complication of acute myocarditis. A 12-year-old female who developed symptoms of motor dysphasia and incomplete hemiparesis of the right side was admitted to the hospital. The brain MRI taken on the day of her admission showed acute cerebral infarction in the left basal ganglia and the frontoparietal lobe. The echocardiogram showed a movable thrombus, which was $19{\times}28mm$ sized and located in the apex of the left ventricle. So in order to prevent further thromboembolic event we performed open cardiac surgery via the atrium and removed the thrombus of the left ventricle. After the removal of the thrombus her symptoms improved and she was discharged from the hospital. Thrombus formation in acute viral myocarditis are considered to be related with endocardial injury and blood flow stasis. Treatment with anticoagulants in left ventricular thrombosis may not be effective and may even cause a major thromboembolism. When the thrombus is laminar and fixed, one should consider anticoagulant therapy. But if the thrombus is pedunculated and movable, which means that there are higher possibilities of major embolism or there may be already one, one should consider surgical removal. We report a 12-year-old girl who required surgical removal of a left ventricular thrombus caused by acute viral myocarditis.

PL 사례에 대응한 제품안전성 제고방안

  • 임현교
    • Proceedings of the Korean Reliability Society Conference
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    • 2001.06a
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    • pp.375-375
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    • 2001
  • 금년 7월 1일부터 개정 시행되는 품질경영촉진 및 공산품안전관리범파, 2002 년 7 월 1 일부터 시행되는 제조물책임(Product Liability; PL)법으로 인하여 제품의 안전성을 제고하기 위한 노력이 정부와 기업. 학계에서 다각도로 진행중이다. 그러나, 그 추진방향들이 아직 제각각이어서 하나의 조직적인 체계를 갖추진 못하고 있다. 그 이유는 제조물책임에 대응하기 위한 제품안전성 향상이 어느 한 분야의 활동으로는 충족시킬 수 없기 때문이지만, 기본적으로는 제품안전이 담당하여야 하는 책임의 범위가 어디까지인지 기업을 비롯한 관계자들이 명확히 이해하고 있지 못하기 때문이다. 본 연구에서는 이와 관련하여, 기존에 이미 시행착오를 겪은 선진국들의 소송사례를 중심으로 제품결함 중 어느 부분에 문제가 제기되는가를 살펴보고, 그 대응책을 제시하고자 하였다. 먼저 제조물책임법의 제정 취지와 법에서 정하고 있는 책임범위가 어디까지인지를 살펴보고, 선진국의 소송사례를 중심으로 그 적용범위를 확인하였다 또한 제조물책임에 대응하기 위한 방법이 어떻게 진행되는지를 살펴보고, 그 중 제품 안전성 (Product Safety) 을 향상시키기 위하여 신뢰성이나 품질측면에서 경영상의 어떤 노력이 경주되어야 하는가를 검토하였다. 한편, 리스크 관리상의 리스크 분석과 위험성 분석과의 관계, 위험성 분석의 기법들, 위험성 분석기법의 선정요령, 제품의 안전성을 평가하기 위하여 기존의 위험성 분석기법을 어떻게 활용할 것인가, 적용상의 문제점은 없는가 검토하였다. 마지막으로, 현재 기업들이 가장 소홀하게 대응하고 있는 표시상의 결함에 대하여 소송 및 보상사례를 살펴보고, 그에 대한 대책으로서 픽토그램, 라벨, 경고문구, 그리고 사용설명서의 작성 및 표시 방안에 대하여 대응방안을 고찰하였다. 용융이 발생될 수 있다. 따라서, 이러한 현상을 방지하기 위해서는 진공 분위기 하에서 적절한 접합 틈새를 유지할 수 있는 공정 및 장비의 개발이 필요하다.(Icing화) 문제가 발생하기 때문에 배기가스의 Icing을 방지하기 위하여 압축기 끝단에서 공기를 추출하여 배기부분에 송출할 필요성이 있는 것으로 판단되었다. 출구가스의 기체 유동속도가 매우 빠르므로 (100-l10m.sec) 이를 완화하기 위한 디퓨저의 설계가 요구된다고 판단된다. 또 연소기 후방에 물을 주입하는 경우 열교환기 및 기타 부분품에 발생할 수 있는 부식 및 열교환 효율 저하도 간과할 수 없는 문제로 파악되었다. 이러한 기술적 문제가 적절히 해결되는 경우 비활성 가스 제너레이터는 민수용으로는 대형 빌딩, 산림, 유조선 등의 화재에 매우 적절히 사용되어 질 수 있을 뿐 아니라 군사적으로도 군사작전 중 및 공군 기지의 화재 그리고 지하벙커에 설치되어 있는 고급 첨단 군사 장비 등의 화재 뿐 아니라 대간첩작전 등에 효과적으로 활용될 수 있을 것으로 판단된다.가 작으며, 본 연소관에 충전된 RDX/AP계 추진제의 경우 추진제의 습기투과에 의한 추진제 물성 변화는 미미한 것으로 나타났다.의 향상으로, 음성개선에 효과적이라고 사료되었으며, 이 방법이 편측 성대마비 환자의 효과적인 음성개선의 치료방법의 하나로 응용될 수 있으리라 생각된다..7%), 혈액투석, 식도부분절제술 및 위루술·위회장문합술을 시행한 경우가 각 1례(2.9%)씩이었다. 13) 심각한 합병증은 9례(26.5%)에서 보였는데 그중 식도협착증이 6례(17.6%), 급성신부전증 1례(2.9%), 종격동기흉과 폐염이 병발한 경우와 폐염이 각 1례(2.9%)였다. 14) 식도경 시행회수는 1회가 17례(54.8%), 2회가 9례(29.0%), 3회 이상이

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Effects of Feeding High and Low Ca Additive on Laying Performance and Egg Quality in Laying Hens (산란계 사료 내 칼슘의 수준별 첨가 급여가 생산성 및 계란 품질에 미치는 영향)

  • Kang, Hwan-Ku;Kang, Geun-Ho;Kim, Dong-Wook;Na, Jae-Cheon;Yu, Dong-Jo;Lee, Sang-Jin;Kim, Sang-Ho
    • Journal of Animal Science and Technology
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    • v.50 no.6
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    • pp.799-806
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    • 2008
  • This experiment was carried out to investigate the effect of feeding limestone to high and low Ca layer diets on laying performance and eggshell quality in laying hens. Five hundred and twenty-eight HyLine brown layer allotted to six treatments consisting of high and low Ca diets. Limestone added to two kinds of basal diet with 1, 2 and 3 fold compared to conventional diet. Egg production was not different regardless Ca level and amount of added limestone in overall periods. However, the increment of egg observed in high Ca diet and added 10g limestone group during later period. Ca and limestone intake were increased as increasing feeding limestone. Eggshell strength and thickness were improved in high Ca consumption group. It was concluded that feeding Ca sources to conventional diets was helpful improving eggshell quality and reducing feed cost per egg mass by increasing proportion of Ca intake.