• 해양환경안전학회지
• /
• 제18권5호
• /
• pp.481-487
• /
• 2012

최근 FRP 선박의 폐선 처리문제, 환경 규제의 강화, 자원 재활용 등의 관점에서 소형 알루미늄 합금 선박의 건조가 증가하는 추세이다. 그러나 알루미늄은 가볍기 때문에 해양에서 고속으로 운행 가능한 알루미늄 선박은 캐비테이션이 발생되어 기포붕괴에 따른 큰 충격압력에 의해 캐비테이션 침식이 일어남으로서 재료의 수명에 있어 문제점을 드러내고 있다. 따라서 본 연구에는 캐비테이션에 의한 손상을 방지하여 내구 수명을 연장시키기 위한 방법으로 워터 캐비테이션 피닝 기술을 선박용 알루미늄 합금에 적용하였다. 이를 위하여 워터 캐비테이션 피닝을 실시하여 내캐비테이션 특성이 가장 우수한 적용 시간을 규명하였다. 선박용 알루미늄 합금 5456-H116, 5083-H321 그리고 5052-O는 워터캐비테이션 피닝을 실시함으로써 내캐비테이션 특성이 워터 캐비테이션 피닝을 하지 않은 시편보다 무게감소량이 각각 42.11 %, 50.0 % 그리고 25.7 % 개선되었다.

• 동의생리병리학회지
• /
• 제24권4호
• /
• pp.638-645
• /
• 2010

The aim of this study was to investigate the effect of Taeeumjowuitanggagam-bang (TJV) on the mRNA expression of Sterol regulatory element binding proteins (SREBPs), Tumor necrosis factor-$\alpha$ (TNF-$\alpha$) and Interlukin-6 (IL-6) that are considered to play an important role in lipid and glucose metabolism. For diet-induced obese studies, we split mice into 2 groups. The low fat diet group (LFD, n=8) were supplied with general diet for 10 weeks and the high fat diet group (HFD, n=18) were supplied with 60 kcal% fat diet for 10 weeks. And then The HFD group, the diet-induced obese group, were divided into 3 groups ; a group supplied with normal saline, a group treated with TJV 200 mg/kg and a group treated with TJV 500 mg/kg. They were treated orally with TJV and measured their body weight every day during 10 weeks. After that, we measured mRNA expressions of TNF-$\alpha$, IL-6 and SREBP-1c in liver, and blood concentrations of glucose, total cholesterol and triglyceride too. The results are as follows. The TJV reduced glucose and total cholesterol of blood concentration. The TJV reduced the mRNA expressions of TNF-$\alpha$ and SREBPs in liver. However, We couldn't find the TJV effects on the mRNA expression of IL-6, triglyceride blood concentration, and body weight among groups. The TJV stained liver tissue less red than control group. These results suggest that TJV may be effective for regulation of lipid and glucose metabolism in liver.

• 대한기계학회논문집A
• /
• 제40권6호
• /
• pp.595-602
• /
• 2016

자동차용 휠 베어링은 회전운동을 전달하고 차량의 무게를 지지해주는 중요한 부품이다. 최근 $CO_2$ 배출가스 저감과 연비 규제에 따라서 자동차 경량화 및 소형화 요구는 점점 증가하고 있고, 이에 부응하여 베어링의 수명 평가기술은 더욱 그 필요성이 증가하고 있다. 휠 베어링의 내구수명은 고려해야 할 인자들이 매우 다양하며 이들이 서로 복잡하게 연관되어 있으므로 수명을 예측하는 것이 쉽지 않다. 본 논문에서는 자동차용 휠 베어링의 수명에 영향을 끼치는 많은 인자들 중에서 작동하중과 회전속도를 변화시키면서 수명을 시험하였고, 이를 ISO 국제표준에서 제안하는 이론수명인 기본정격수명과 보정정격수명 결과와 비교하였다. 이들 수명을 비교한 결과, 기본정격수명과 보정정격수명 모두 시험수명과 차이가 존재하며, 기본정격수명 보다 보정정격수명이 시험수명을 상대적으로 잘 예측함을 알 수 있었다.

• 생약학회지
• /
• 제42권2호
• /
• pp.201-208
• /
• 2011

Obesity occur from the imbalance between energy intake and energy expenditure. Obesity is a complex chronic disease that is suggested to cause other metabolic disorders such as type 2 diabetes, hyperlipidemia, hypertension, and arteriosclerosis. In this study, our purpose is to investigate the anti-hyperglycemic and anti-obesitic effects of Maydis stigma water extract in 3T3-L1 adipocytes and db/db mice. Maydis stigma water extract at dose of 100 and 500 ${\mu}g/ml$ slowly inhibited cell viability as compared to that of control in mature adipocytes. Also, the additions of 50 and 250 ${\mu}g/ml$ of Maydis stigma water extract significantly inhibited the lipid accumulations and CCAAT/enhancer-binding protein(C/EBP) ${\alpha}$ and peroxisome proliferator-activated receptor(PPAR) ${\gamma}$ expressions with dose-dependent manner in 3T3-L1 adipocytes. Maydis stigma water extract at 250, 500, and 1000 ${\mu}g/ml$ only showed the increasing pattern on lipolysis activity. The oral treatment of Maydis stigma water extract (100 or 400 mg/kg body weight) in db/db mice only showed tendency to decrease body weight, food efficiency ratio (FER), HbA1c, blood glucose, total cholesterol, triglyceride, and the adipocyte size of in db/db mice. However, Maydis stigma water extract increased the insulin level in a dose dependent manner. Thus these results indicate that Maydis stigma water extracxt inhibits adipogenesis through regulation of C/EBP${\alpha}$ and PPAR${\gamma}$ expressions in 3T3-L1 adipocytes and shows anti-hyperglycemic effect through increase of insulin secretion in db/db mice.

• Reproductive and Developmental Biology
• /
• 제34권4호
• /
• pp.299-304
• /
• 2010

To identify the treatment effect of lactic acid bacteria for diabetes, the treatment effects of a single administration of acarbose (a diabetes treatment drug) or lactic acid bacteria, and the mixture of acarbose and lactic acid bacteria on diabetes in a type 1 diabetes animal model, were studied. In this study, streptozotocin was inoculated into a Sprague-Dawley rat to induce diabetes, and sham control (Sham), diabetic control (STZ), STZ and composition with live cell, STZ and composition with heat killed cell, STZ and composition with drugs (acarbose) were orally administered. Then the treatment effect on diabetes was observed by measuring the body weight, blood glucose, and serum lipid. For the histopathological examination of the pancreas, the Langerhans islet of the pancreas was observed using hematoxylin and eosin staining, and the renal cortex, outer medullar, and inner medullar were also observed. The induced diabetes decreased the body weight, and the fasting blood glucose level decreased in the lactic-acid-bacteria-administered group and the mixture-administered group. In addition, the probiotic resulted in the greatest decrease in the serum cholesterol level, which is closely related to diabetes. Also, the hematoxylin and eosin staining of the Langerhans islet showed that the reduction in the size of the Langerhans islet slowed in the lactic-acid-bacteria-administered group. The histopathological examination confirmed that the symptoms of diabetic nephropathy decreased in the group to which viable bacteria and acarbose were administered, unlike in the group to which dead bacteria was administered. The mixture of lactic acid bacteria and acarbose and the single administration of lactic acid bacteria or acarbose had treatment effects on the size of the Langerhans islet and of the kidney histopathology. Thus, it is believed that lactic acid bacteria have treatment effects on diabetes and can be used as supplements for the treatment of diabetes.

• Nutrition Research and Practice
• /
• 제7권6호
• /
• pp.460-465
• /
• 2013

The hepatoprotective activity of Acanthopanax koreanum Nakai extract (AE) was investigated against D-Galactosamine/Lipopolysaccharide (D-GalN/LPS)-induced liver failure rats compared with that of acanthoic acid (AA) isolated from AE. Although D-GalN/LPS (250 mg/kg body weight/$10{\mu}g/kg$ body weight, i.p.) induced hepatic damage, pretreatments with AE (1 and 3% AE/g day) and AA (0.037% AA, equivalent to 3% AE/g day) alleviated the hepatic damage. This effect was the result of a significant decrease in the activity of alanine transaminase. Concomitantly, both the nitric oxide and IL-6 levels in the plasma were significantly decreased by high-dose AE (AE3) treatment compared to the GalN/LPS control (AE0). This response resulted from the regulation of pro-inflammatory signaling via a decrease in TLR4 and CD14 mRNA levels in the liver. While a high degree of necrosis and hemorrhage were observed in the AE0, pretreatment with AE3 and AA reduced the extent of hepatocyte degeneration, necrosis, hemorrhage and inflammatory cell infiltrates compared to the AE0. In conclusion, these results suggest that especially high-dose AE are capable of alleviating D-GalN/LPS-induced hepatic injury by decreasing hepatic toxicity, thereby mitigating the TLR 4-dependent cytokine release. The anti-inflammatory effect of AE could be contributing to that of AA and AE is better than AA.

• 한국응용과학기술학회지
• /
• 제37권3호
• /
• pp.385-397
• /
• 2020

본 연구는 수영운동이 백색지방조직의 혈관신생을 조절함으로써 비만을 개선하는지를 조사하였다. 고지방식이를 섭취한 암컷 쥐는 모의 수술 군(Sham), 난소절제 수술 군(OVX) 및 수영운동을 실시한 난소절제 군(OVX + Swim)으로 나뉘었다. Sham에 비해 OVX는 몸무게, 지방조직무게 및 지방세포의 크기가 증가 되었다. 그러나 OVX + Swim의 이러한 요소들(: 몸무게, 지방조직무게 및 지방세포의 크기)은 OVX에 비해 감소 되었다. Sham에 비해 OVX는 백색지방조직에서 혈관신생 촉진인자와 MMPs의 유전자 발현이 증가하였고, 혈관신생 억제인자들의 유전자 발현은 감소하였다. 그러나 OVX + Swim은 OVX에 비해 백색지방조직에서 혈관신생 촉진인자와 MMPs의 유전자 발현이 감소하였고, 혈관신생 억제인자들의 유전자 발현은 증가하였다. 이러한 연구결과들은 고지방식이를 섭취한 난소절제 암컷 쥐에서 수영운동이 백색지방조직의 혈관신생을 억제함으로써 비만을 개선한다는 것을 제시하였다.

• 대한지역사회영양학회지
• /
• 제16권1호
• /
• pp.126-135
• /
• 2011

Obesity is characterized by increased storage of fatty acids in an adipose tissue and closely associated with the development of insulin resistance and cardiovascular diseases (CVD) through secretion of adipokines. This study was done to compare serum insulin, leptin, adiponectin and high sensitivity C-reactive protein (hs-CRP) levels according to body masss index (BMI) in Korean adult women aged 19 to 50. In addition, we examined the association of BMI, serum lipids and Homa-IR with serum adiponectin, leptin and hs-CRP levels. The subjects were divided into 3 groups by their BMI, normal weight (BMI ${\leq}$ 22.9, n = 30), overweight (23.0 ${\leq}$ BMI ${\leq}$ 24.9, n = 71) and obese group (25.0 ${\leq}$ BMI, n = 59). Serum levels of total-cholesterol, TG, and LDL-cholesterol were significantly higher in obese group than in normal weight group. LDL/HDL ratio and AI were significantly higher in obese group than in normal or overweight group. Fasting serum levels of glucose and insulin and Homa-IR as a marker of insulin resistance were significantly higher in obese group than in overweight group. Serum leptin level was significantly higher in obese group while serum adiponectin level was significantly lower in obese group compared to other two groups. hs-CRP was significantly increased in obese group. Correlation data show that serum adiponectin level was positively correlated with serum HDLcholesterol level and was negatively correlated with BMI, WC, TG, LDL-cholesterol, Homa-IR, hs-CRP and leptin. In addition, serum leptin level was positively correlated with BMI, WC, glucose, insulin, Homa-IR and hs-CRP. These results might imply that the regulation of key adipokines such as adiponectin might be a strategy for the prevention or treatment of obesity-associated diseases such as diabetes and CVD.

• 생명과학회지
• /
• 제9권3호
• /
• pp.253-261
• /
• 1999

Leptin gene, an obesity gene, has been known to involve in the regulation of food intake and body weight. It is also thought to be related to the glucose metabolism, insulin secretion and type II diabetes mellitus. Recently, the production of recombinant leptin protein has been attempted for the application in the treatment of obesity and the correction of hereditary obesity and type II diabetes. In the present study, leptin cDNA was cloned from mouse fat cells by RT-PCR and prokaryotic expression of leptin was attempted in order ot prepare a leptin-specific antigen. Immunization of a rabbit with the leptin-specific antigen into a rabbit resulted in the generation of leptin-specific antiserum that could be useful in the detection of leption expressed in various tissues. The sequence of leptin cDNA prepared in the present study wa identical to the previously reported one. Transformation of E. coli(DH5a) cells with the leptin cDNA-inserted translation vector, pGEX-4T-3-leptin followed by treatment with IPTG (0.1mM) resulted in the expression of a large amount of GST-leptin fusion protein with a molecular weight of 44 KDa as an inclusion body. Denaturation of the insoluble fusion protein by 8M urea, 6M guanidium-HCI or 0.1% 2-mercaptoethanol followed by a slow oxidation could not solubilize the inclusion body. The cell extract was subjected to SDS-PAGE and GST-leptin protein electroeluted from the gel was then injected into a rabbit subcutaneously for the immunization. Anti-GST-leptin rabbit antiserum which had a cross reactivity to the GST-leptin protein was generated. Leptin protein expressed in mouse brain and fat tissues was detected by Western blot immunodetection system using the antiserum generated in the present study.

• Molecules and Cells
• /
• 제40권3호
• /
• pp.186-194
• /
• 2017

A brain-enriched secreting signal peptide, NELL2, has been suggested to play multiple roles in the development, survival, and activity of neurons in mammal. We investigated here a possible involvement of central NELL2 in regulating feeding behavior and metabolism. In situ hybridization and an immunohistochemical approach were used to determine expression of NELL2 as well as its colocalization with proopiomelanocortin (POMC) and neuropeptide Y (NPY) in the rat hypothalamus. To investigate the effect of NELL2 on feeding behavior, 2 nmole of antisense NELL2 oligodeoxynucleotide was administered into the lateral ventricle of adult male rat brains for 6 consecutive days, and changes in daily body weight, food, and water intake were monitored. Metabolic state-dependent NELL2 expression in the hypothalamus was tested in vivo using a fasting model. NELL2 was noticeably expressed in the hypothalamic nuclei controlling feeding behavior. Furthermore, all arcuatic POMC and NPY positive neurons produced NELL2. The NELL2 gene expression in the hypothalamus was up-regulated by fasting. However, NELL2 did not affect POMC and NPY gene expression in the hypothalamus. A blockade of NELL2 production in the hypothalamus led to a reduction in daily food intake, followed by a loss in body weight without a change in daily water intake in normal diet condition. NELL2 did not affect short-term hunger dependent appetite behavior. Our data suggests that hypothalamic NELL2 is associated with appetite behavior, and thus central NELL2 could be a new therapeutic target for obesity.