• Nutrition Research and Practice
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• 제11권3호
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• pp.198-205
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• 2017

BACKGROUND/OBJECTIVES: The anti-diabetic activity of pear through inhibition of ${\alpha}-glucosidase$ has been demonstrated. However, little has been reported about the effect of pear on insulin signaling pathway in obesity. The aims of this study are to establish pear pomace 50% ethanol extract (PPE)-induced improvement of insulin sensitivity and characterize its action mechanism in 3T3-L1 cells and high-fat diet (HFD)-fed C57BL/6 mice. MATERIALS/METHODS: Lipid accumulation, monocyte chemoattractant protein-1 (MCP-1) secretion and glucose uptake were measure in 3T3-L1 cells. Mice were fed HFD (60% kcal from fat) and orally ingested PPE once daily for 8 weeks and body weight, homeostasis model assessment of insulin resistance (HOMA-IR), and serum lipids were measured. The expression of proteins involved in insulin signaling pathway was evaluated by western blot assay in 3T3-L1 cells and adipose tissue of mice. RESULTS: In 3T3-L1 cells, without affecting cell viability and lipid accumulation, PPE inhibited MCP-1 secretion, improved glucose uptake, and increased protein expression of phosphorylated insulin receptor substrate 1 [p-IRS-1, ($Tyr^{632})$)], p-Akt, and glucose transporter type 4 (GLUT4). Additionally, in HFD-fed mice, PPE reduced body weight, HOMA-IR, and serum lipids including triglyceride and LDL-cholesterol. Furthermore, in adipose tissue, PPE up-regulated GLUT4 expression and expression ratio of p-IRS-1 ($Tyr^{632})/IRS$, whereas, down-regulated p-IRS-1 ($Ser^{307})/IRS$. CONCLUSIONS: Our results collectively show that PPE improves glucose uptake in 3T3-L1 cells and insulin sensitivity in mice fed a HFD through stimulation of the insulin signaling pathway. Furthermore, PPE-induced improvement of insulin sensitivity was not accompanied with lipid accumulation.

• 한국미생물·생명공학회지
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• 제16권6호
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• pp.489-493
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• 1988

Starch로부터 ethanol을 직접적으로 발효 생산할 수 있는 새로운 효모 균주를 개발하고자 glucoamylase 생성균으로 알려진 Saceharomyces diastaticus의 glucoamylase gene을 cloning vector를 사용하지 않고 S, cerevisiae에 transformation시켰다. Li$_2$SO$_4$, 처리로써 competent화 한 S, cerevisiae의 Intact cells을 recipient로 하여 BamHI으로 partial digestion한 S, diastaticus의 chromosomal DNA를 transformation시키고 starch를 유일한 탄소원으로 함유한 최소 배지상에서 starch 자화능을 marker로 하여 transformant를 선별한 결과, 8.5$\times$$10^{-7}$ 빈도로 transformant를 얻었다. Transformant의 특성을 recipient 및 donor와 비교하기 위해 copper resistance와 당 발효능을 조사한 결과, donor인 S, diastaticus와 동일한 성질로서 표현된 maltose와 starch 발효능을 제외하고는 800ppm 농도까지 생육 가능한 copper resistance와 galactose 발효능 등에 있어서는 recipent와 동일하게 나타났다. 또한 transformant가 생성하는 glucoamylase의 그 작용에 있어서의 최적온도와 최적pH를 조사하여 본 바 각각 pH5.0, 50C로서 donor의 glucoamylase와 동일함을 알 수 있었다.

• 한국표면공학회:학술대회논문집
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• 한국표면공학회 2018년도 춘계학술대회 논문집
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• pp.67-67
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• 2018

The 5xxx series aluminum alloys are recently used in not only marine system but also automotive area because of a low density material, good mechanical properties and better resistance to corrosion. However, Aluminum alloys are less resistant than the purest aluminum such as 1xxx aluminum alloy. Electrochemical anodization technique has attracted in the area of surface treatment because of a simple procedure, a low-cost efficiency than other techniques such as lithography and a large volume of productivity, and so on. Here, The relationship between the corrosion behavior and the thickness of aluminum anodic oxide have been studied. Prior to anodization, The 5052 aluminum sheets ($30{\times}20{\times}1mm$) were degreased by ultra-sonication in acetone and ethanol for 10 minutes and eletropolished in a mixture of perchloric acid and ethanol (1:4, volume ratio) under an applied potential of 20V for 60 seconds to obtain a regular surface. During anodization process, Aluminum alloy was used as a working electrode and a platinum was used as a counter electrode. The two electrodes were separated at a distance of 5cm. The applied voltage of anodization is conducted at 40V in a 0.3M oxalic acid solution at $0^{\circ}C$ with appropriate magnetic stirring. The surface morphology and the thickness of AAO films was observed with a Scanning Electron Microscopy (SEM). The corrosion behavior of all samples was evaluated by an open-circuit potential and potentio-dynamic polarization test in 3.5wt% NaCl solution. Thus, The corrosion resistance of 5052 aluminum alloy is improved by the formation of an anodized oxide film as function of increase anodization time which artificially develops on the metal surface. The detailed electrochemical behavior of aluminum 5052 alloy will be discussed in view of the surface structures modified by anodization conditions such as applied voltages, concentration of electrolyte, and temperature of electrolyte.

• Nutrition Research and Practice
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• 제7권6호
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• pp.446-452
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• 2013

Chronic consumption of a high-fat, high-sucrose (HFHS) diet increases insulin resistance and results in type 2 diabetes mellitus in C57BL/6J mice. Hyperglycemia in diabetics increases oxidative stress, which is associated with a high risk of diabetic complications. The purpose of this study was to examine the hypoglycemic and antioxidant effects of chamnamul [Pimpinella brachycarpa (Kom.) Nakai] in an animal model of type 2 diabetes. The ${\alpha}$-glucosidase inhibitory activity of a 70% ethanol extract of chamnamul was measured in vitro. Five-week-old male C57BL/6J mice were fed a basal or HFHS diet with or without a 70% ethanol extract of chamnamul at a 0.5% level of the diet for 12 weeks after 1 week of adaptation. After sacrifice, serum glucose, insulin, adiponectin, and lipid profiles, and lipid peroxidation of the liver were determined. Homeostasis model assessment for insulin resistance (HOMA-IR) was determined. Chamnamul extract inhibited ${\alpha}$-glucosidase by 26.7%, which was 78.3% the strength of inhibition by acarbose at a concentration of 0.5 mg/mL. Serum glucose, insulin, and cholesterol levels, as well as HOMA-IR values, were significantly lower in the chamnamul group than in the HFHS group. Chamnamul extract significantly decreased the level of thiobarbituric acid reactive substances and increased the activities of superoxide dismutase, catalase, and glutathione peroxidase in the liver compared with the HFHS group. These findings suggest that chamnamul may be useful in prevention of hyperglycemia and reduction of oxidative stress in mice fed a HFHS diet.

• 한국식품영양과학회지
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• 제33권8호
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• pp.1268-1272
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• 2004

본 연구에서는 천년초 손바닥 선인장 유기용매 추출물의 항균성을 비교, 검토하고자 하였다. 70% ethanol로 추출하여 hexan, chloroform, ethyl acetate, buthanol, water로 순차 분획하여 ascorbic acid, benzoic acid와 항균효과를 비교하여 보았다. Escherichia coli 등 Gram positive bacteria 2종, Gram negative bacteria 2종, yeast 1종 등 총 6개의 병원성 식중독 미생물에 대해 항균효과를 검토한 결과 ethyl acetate 분획물이 가장 우수한 항균효과를 나타내었고 이는 동량의 benzoic acid보다 월등히 우수하였다. Gram positive bacteria와 Gram negative bacteria에 대해 유의적 차이가 없는 비슷한 항균효과를 보여주었으나 bacteria에 비해 yeast에서 항균효과는 낮게 나타났다.

• 센서학회지
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• 제27권4호
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• pp.221-226
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• 2018

Misfueling accidents significantly damage the engines of both gasoline and diesel vehicles, and should be avoided by rapid and accurate fuel discrimination. Gasoline fuel contains bioethanol. Thus, the detection of ethanol vapor produced by gasoline can be used to distinguish between gasoline and diesel. In the present study, Pt-doped $SnO_2$ hollow nanospheres, Mg-doped $In_2O_3$ hollow microspheres, and Pt-doped ZnO nanostructures have been used as gas sensors to discriminate between gasoline and diesel fuels. All three sensors are able to detect and discriminate between gases evaporating from gasoline and diesel. Among the sensors, the Mg-doped $In_2O_3$ hollow microspheres show a significant gas response (resistance ratio = 4.97) quickly (~3 s) after exposure to gasoline-evaporated gas at $225^{\circ}C$, but did not show any substantial response to diesel-evaporated gas. This demonstrates that gasoline and diesel fuels can be discriminated using small and cost-effective oxide semiconductor gas sensors.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2003년도 추계학술대회
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• pp.13-18
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• 2003

Heat pipes with binary mixture fabricated and tested for applications where condenser temperature is in a range of $10^{\circ}C$ to $130^{\circ}C$. The pipe materials 8.0 mm O.D. cupper tube and the working fluids are ethanol-water mixtures. The total length of test of the heat pipe was 1710mm in which evaporator section was 1570mm, adiabatic section was 50mm and condenser section was 90mm. Mixing ratios of ethanol and water could be variable in mole fraction. Temperature of condenser section was $10^{\circ}C$, $80^{\circ}C$ and $130^{\circ}C$. Heat pipe performance experimental study was accomplished with change of mixing ratio in these temperatures. The fill charge ratio was 20% of the heat pipe volume. Wick structure was woven-wire and method of experimental work was that thermal load was increased 20W step until the heat pipe wall temperature reached at $150^{\circ}C$. Results were following: At coolant $10^{\circ}C$ and $130^{\circ}C$, mixing ratio that have beat thermal performance was 0.8M+ and at coolant $80^{\circ}C$, was 0.3 ${\sim}$ 0.5 M+.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년도 제37회 하계학술대회 논문집 C
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• pp.1390-1391
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• 2006

본 연구에서는 전도성 분자로 잘 알려진 4,4-Di(ethynyl phenyl) -2'-nitro-1-(thioacetyl)-benzene(nitro - benzene) 분자를 Au (111) 표면에 자기조립하고, ultra high vacuum scanning tunneling microscopy (UHV-STM)을 사용하여 STM tip과 sample 사이의 거리를 변화시키면서 전기전도 특성을 측정하였다. Au 기판제작은 연증착시스템 (Thermal Evaporation System)으로 제작하였으며, piranha 용액 ($H_{2}SO_{4}\;:\;H_{2}O_{2}$=3:1)을 사용하여 전치리한 후, 자기조립 단분자막 (SAMs)을 형성하였다. 먼저 1-octanethiol을 ethanol solution용액 1 mM/L 농도에서 24시간 동안 자기조립한 후에, ethanol를 solution 용액으로 이용하여 nitro-benzene를 0.1 nM/L 농도로 암실에서 30분간 자기조립 하였다. 자기조림 후 solution을 제거하기 위해 에탄올로 세척하여 $N_2$로 건조시켰다. 이 조건하에서 UHV-STM을 사용하여 nitro-benzene SAMs의 실시간 모폴로지의 변화에 따른 nitro-benzene의 전기전도 특성을 STM tip - SAMs - Au 기판의 수직구조로 STM tip과 nitro-benzene의 거리를 변화시키면서, tunneling current을 조사하였다. 측정 결과 Z-position 변화에 대한 tunneling current와 resistance의 변화를 확인할 수 있었다.

• 한국발생생물학회지:발생과생식
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• 제21권3호
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• pp.259-267
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• 2017

Present study aimed to determine the effect of 'bitter melon', a popularly used fruit in Bangladesh and several other Asian countries, on high-fat-diet-induced type 2 diabetes. To investigate the effect, ethanol extract from bitter melon (BME) as a dietary supplement with mouse chow was used. BME was found to significantly attenuate the high-fat diet (HFD) -induced body weight and total fat mass. BME also effectively reduced the insulin resistance induced by the HFD. Furthermore, dietary supplementation of BME was highly effective in increasing insulin sensitivity and reducing hepatic fat and obesity. These results indicate that BME could be effective in attenuating type 2 diabetes and could therefore be a preventive measure against type 2 diabetes.

• 한국결정성장학회지
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• 제13권3호
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• pp.139-144
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• 2003

유기용매로서 에탄올을 함유한 염화니켈 수용액으로부터 니켈 미분말을 제조하고 이들의 산화특성을 검토하였다. 에탄올을 함유한 염화니켈 수용액에서 히드라진의 환원반응은 반응온도에 크게 의존하였다. 히드라진에 의한 환원반응시간은 반응온도가 증가함에 따라 감소하였다. 반응온도를 제어함으로써 입경이 0.1 $\mu\textrm{m}$-1.0 $\mu\textrm{m}$ 범위를 갖는 구형 분말을 얻을 수 있었다. 또한, 반응온도가 증가함에 따라 입경은 다소 증가하였고 조대한 입자들의 존재로 인하여 넓은 입도 분포를 나타내었다. $60^{\circ}C$에서 합성된 니켈 분말의 평균 입경과 비표면적은 각각 0.3 $\mu\textrm{m}$와 31.8 $m^2$/g이었다. $300^{\circ}C$에서 니켈 분말의 중량감소는 $Ni(OH)_2$의 분해반응에 기인한 것이다. $200^{\circ}C$ 공기중에서 가열처리한 경우 내산화성은 합성 분말보다 현저하였다