• 조명전기설비학회논문지
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• 제16권5호
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• pp.66-74
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• 2002

OFDM(Orthogonal Frequency Division Multiplexing)변조방식은 데이터를 다수의 반송파를 이용해서 주파수상 에서 분산해서 전송하는 디지털변조방식의 일종으로, 멀티패스 간섭에 강한 이점 등으로 인해 디지털음성방송이나 지상파 디지털TV방송 등에 적용되고 있으며, 1997년부터는 5［㎓］대역의 구내용 초고속무선LAN설비로서 IEEE 802.11 TG(task group)a에서 규격작업이 이뤄짐에 따라, 관련된 연구들이 활발하게 진행되어지고 있다. OFDM방식의 초고속무선LAN설비를 구현하기 위한 송수신부의 핵심소자로서는 IEFT 및 FFT모듈이 있다. 본 논문은 IFFT및 FFT모듈을 행렬 원소의 라운딩기법을 기반으로 한 전류모드회로를 이용해서 설계 및 구현함으로써 저소비전력화와 고속처리동작이 가능하도록 하였다. 또한 제안한 IFFT 및 FFT모듈을 IEEE 802.11a규격에 근거한 송수신부 모뎀에 적용한 경우에 대한 BER특성을 모의실험을 통해 확인함으로써, 제안한 IFFT 및 FFT모듈을 이용한 송수신 시스템 설비가 AWGN채널 환경에서 유용하게 동작함을 입증하였다.

• Asian-Australasian Journal of Animal Sciences
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• 제12권7호
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• pp.1090-1095
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• 1999

In order to minimize the occurrence of fatty liver, this study investigated how adding a high level of dietary choline or methionine affected the lipid metabolism of Tsaiya ducks. Feeding trials were conducted with sixty Tsaiya ducks during their growing period, when they were 8-12 weeks old, and during their laying period, 10-14 weeks after the onset of laying when they were 26-30 weeks old. The ducks were randomly assigned to one of three groups: a control group (basal diet), a group in which methionine was added to the basal diet, and a group in which choline was added to the basal diet. The levels of methionine and choline added were twice as high as the levels recommended by the NRC for layer-type chickens. Experimental results indicated that adding choline to the basal diet of growing ducks significantly (p<0.05) increased their body weight, while adding methionine significantly (p<0.05)reduced their body weight. Adding either choline or methionine reduced the ducks' liver fat content in both the growing and the laying periods (p<0.05). Ducks receiving added methionine or choline in their diets displayed enhanced egg production (p<0.05). Adding choline increased serum triacylglycerol (TG) in the laying period (p<0.05). Adding either choline or methionine did not significantly (p>0.05) affect the t-globulin level. Adding methionine increased the activity of liver malic dehydrogenase in both the growing and the laying periods, and increased fatty acid synthetase in the laying period (p<0.05). While adding choline markedly (p>0.05) increased VLDL and apo B in both the growing and the laying periods, it decreased HDL and apo A in the laying period (p<0.05). This study found that adding a high level of choline to the basal diets of Tsaiya ducks in both the growing and the laying periods had beneficial effects. Furthermore, adding methionine affected the lipid metabolism of Tsaiya ducks to a lesser extent than adding choline.

• 한국수의병리학회:학술대회논문집
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• 한국수의병리학회 2002년도 추계학술대회초록집
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• pp.132-132
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• 2002

Mostly, hypercholesterolemia has been focused on atherosclerosis and coronary heart disease and can be produced by intake of high cholesterol diet. However, toxic effects of cholesterol itself on liver and relationship between intake of high cholesterol diet and hepatic fibrosis have not been clearly investigated. Male Wistar rats were fed diet supplemented with 1.0 ％ cholesterol and 0.3 ％ sodium cholate for 12 weeks. Rats were sacrificed at 0, 3, 6, 9 and 12, respectively. Histopathological and blood chemical studies were performed on these animal sets. Total cholesterol, AST, ALT and LDH levels increased from week 3 and maintained around that level throughout the experiment compared to control. However, TG and albumin levels were the same or lower than those of control. Intake of high cholesterol and sodium cholate diet caused hepatic necrosis, macrophage infiltration, steatosis and fibrosis. Following feeding this diet to rats, hepatic necrosis, macrophage infiltration and steatosis markedly increased throughout the experiment, comparing to control. Collagen deposition and myofibroblasts were detected from at week 9 to 12 in the liver. Mast cell increased in proportion to the degree of hepatic damages. In conclusion, these results suggest that intake of high cholesterol diet is a risk factor on hepatic steatosis and fibrosis as well as atherosclerosis and coronary heart disease. Furthermore, this animal model for hepatic fibrosis can be use for application of anti-fibrogenic agents screening in vivo.

• 한국세라믹학회지
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• 제44권6호
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• pp.325-330
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• 2007

High porous AlO(OH) gel is used in precursor of ceramic material, coating material and porous catalyst. For use of these, not only physiochemical control for particle morphology, pore characteristic and peptization but also studies of synthetic method for preparation of high porous AlO(OH) gel were required. In this study, high porous AlO(OH) gel was prepared through the aging and filtration process of aluminum hydroxides gel precipitated by the hydrolysis reaction of $Na_2CO_3$ solution and $Al_2(SO_4)_3$ and $Na_2SO_4$ mixed solution. In this process, optimum synthetic condition of AlO(OH) gel having excellent pore volume as studying the effect of hydrolysis pH on gel precipitates has been studied. Hydrolysis pH brought about numerous changes on crystal morphology, surface area, pore volume and pore size. Physiochemical properties of gel were investigated as using XRD, TEM, TG/DTA, FT-IR and $N_2$ BET method.

• 대한본초학회지
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• 제30권6호
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• pp.83-91
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• 2015

Objectives : The present study was conducted to examine whether Cynanchi wilfordii radix (CWR) with or without fermentation has an ameliorative effect on hyperlipidemia in rats.Methods : We analyzed the contents of Conduritol F on Cynanchi wilfordii radix. The experimental animals were divided into six groups; normal diet fed group (N), high cholesterol fed control group (Con), Lovastatin 20 mg/kg (L), CWR-W 300 mg/kg (CWR-W), and CWR-F 300 mg/kg on hyperlipidemia model induced by feeding 1.25% cholesterol. Rats were administrated orally every day for 8 weeks. And lipid profile of serum and weight change were observed.Results : The vehicle displayed a markedly increased body weight and significantly increased liver and epididymal fat weight, however, the administration of CWR improved the body, liver, and epididymal fat weights. All drug treatment reduced significantly the serum level of total cholesterol and LDL-cholesterol elevated by intake of high cholesterol diet. TG displayed a reducing tendency all drug treatment, however, CWR-W decreased significantly. Atherogenic index and cardiac risk factor increased high cholesterol diet fed control group, while the administration of CWR-W and CWR-F decreased significantly. The major index of liver injury such as AST and ALT improved in all drug treatment.Conclusions : These results suggest that CWR extended the effect of lipid enhanced. Therefore CWR with or without fermentation may be useful for therapeutic treatment of clinical conditions associated with hyperlipidemia. Finally, these require more investigations about the action mechanism of CWR in the future.

• Preventive Nutrition and Food Science
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• 제9권3호
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• pp.259-264
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• 2004

Baek-kimchi (whitish baechu kimchi) was evaluated for anti-obesity properties and effects on triglyceride (TG) and cholesterol in blood and adipose tissues in rats fed a high fat (20 %) diet, and compared to the similar effects of baechu kimchi. Baek-kimchi does not use red pepper powder but contains higher levels of sliced radish and pear than baechu kimchi. SD rats were raised for four weeks on either a normal diet (ND, based on the AIN-93M diet), high fat diet (HFD, supplemented with 16% lard oil in the ND), or HFD containing 5 % baek-kimchi or 5 % baechu kimchi. Feed consumption was not different among the groups, but weight gains were significantly lower in the groups fed either the normal diet or HFD with baek-kimchi or baechu kimchi diets than the group fed HFD alone. The weights of liver and epididymal and perirenal fat pads in baek-kimchi and baechu kimchi diet groups were lower than those of the HFD groups, but the baek-kimchi diet group had lower epididymal and perirenal fat pad weights than the baechu kimchi diet group (p<0.05). The baechu kimchi dietary group also had significantly lower triglyceride and cholesterol contents in liver and epididymal and perirenal fat, reversing the higher levels seen in HFD. Baek-kimchi and baechu kimchi diets were also effective in lowering serum triglyceride and cholesterol levels (p<0.05). These results suggest that baek-kimchi and baechu kimchi consumption can reverse the effects of HFD on weight gain and blood and tissue lipids, and that baek-kimchi is more effective than baechu kimchi. The greater effect is probably due to the higher content of radish and pear used in baek-kimchi.

• 대한한방내과학회지
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• 제40권3호
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• pp.356-368
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• 2019

Objectives: This study was designed to evaluate the efficacy of Pharbitidis Semen (PS) on obesity using 3T3-L1 cells and high-fat-diet rats. Methods: After the administration of PS at a concentration of 0.125, 0.25, and 0.50 mg/ml in 3T3-L1 cells, the degree of differentiation of adipocytes was measured by Oil Red O staining. The experimental animals were divided into five groups in vivo. Normal group: diet-fed normal group (Normal), Control group (Control): high-fat-diet (HFD)-fed, Positive control group (PC): HFD+Contrave 200 mg/kg, PS_Low group: HFD+PS 250 mg/kg group, PS_High group: HFD+PS 500 mg/kg. Results: The total cholesterol, low density lipoprotein-cholesterol (LDL-cholesterol), and triglycerides (TG) content of the PS medication groups were significantly lower than those of the control group. In addition, high density lipoprotein cholesterol (HDL-cholesterol) tended to increase, and free fatty acid, total lipid, and phospholipid tended to decrease, but the decrease was not statistically significant. The administration of PS inhibited the differentiation of 3T3-L1 adipocytes, and a statistically significant difference was found in the group administered with 0.125 mg/ml. The mRNA expression of $PPAR-{\gamma}$ and leptin, which are involved in the differentiation of adipocytes, was observed using reverse transcription polymerase chain reaction (RT-PCR). The expressions of $PPAR-{\gamma}$ and leptin significantly decreased in comparison with the control and the positive control.

• 대한의생명과학회지
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• 제25권3호
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• pp.227-236
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• 2019

In this study, the anti-oxidant, anti-inflammatory, and anti-obesity activities of an ethanol extracts of Ulmus divididiana var. japonica (UDE) were investigated in vitro and in vivo. UDE anti-oxidant activity was evaluated with an Electron Spin Resonance (ESR) spectrometer, which measured 1, 1-diphenyl-2-picryl-hydrazyl (DPPH) radical scavenging activity. Cell viabilities were estimated using 3-[4,5-Dimethylthiazol-2-yl]-2,5-diphenyl-tetrazolium bromide (MTT) assay. LPS-stimulated BV-2 microglia were used to study the production of nitric oxide (NO). Cells stimulated with LPS produce more NO than normal control cells. However, cells treated with the UDE decreased this production in a concentration dependent manner (100, 250, 500, $1,000{\mu}g/mL$). Also, we investigated the anti-obese activity of UDE in SD rats. The SD rats were randomly divided into five groups: 10% low fat diet (N), 45% high fat diet (H), 45% high fat diet + garcinia extracts 200 mg/kg/day (HG200), high fat diet + UDE 200 mg/kg/day (HU200), high fat diet + UDE 400 mg/kg/day (HU400). UDE was found to lower whole body and abdominal and epididymal adipose tissue weights and lowered plasma levels of triglyceride (TG), compared to those in H group. Histological analyses of the liver and fat tissues of rat treated with UDE revealed significantly decreased number of lipid droplets and decreased size of adipocytes compared to the H group. These results suggest that UDE might be used to develop potent anti-oxidant, anti-inflammatory, and anti-obesity agents, and may be useful as ingredients for related new functional raw materials.

• Nuclear Engineering and Technology
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• 제54권1호
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• pp.220-225
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• 2022

Perlite is one of the major constituents of the radioactive thermal insulation waste (RTIW) originating from nuclear power plants and, for proper waste management, a significant reduction in its volume is required prior to disposal. In this work, the volume reduction of perlite is studied by high-temperature treatment method with using K₂CO₃ as a flux. The perlite is ground with 0-30 wt% K₂CO₃, and differential thermal analysis/thermogravimetric analysis is used to monitor the glass transition temperature (T_g) and weight loss. The Tg varied between ~772.2 and 837.1 ℃ with the minima at ~643.5 ℃ with the addition of ~10 wt% K₂CO₃. It is observed that compared to the pure perlite the volume reduction ratio (VRR) increases with the addition of K₂CO₃. The VRR of 11.20 is observed with 5 wt% K₂CO₃ at 700 ℃, as compared to VRR of 5.56 without K₂CO₃ at 700 ℃. The X-ray photoelectron spectroscopy and scanning electron microscopy are used to characterize perlite samples heat-treated without/with 5 wt% K₂CO₃ at 700 ℃. Moreover, the atomic absorption spectroscopy indicates that the proposed heat-treatment procedure is able to completely retain the radionuclides present in the perlite RTIW.

• 한국식품영양과학회지
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• 제42권7호
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• pp.1043-1053
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• 2013

본 연구에서는 대두가공부산물의 하나인 비지(SCR: soybean crud residue)를 이용하여 만든 메주를 항비만 또는 혈중지질 개선용의 식 의약 소재로써의 직접적인 이용 가능성을 검토할 목적으로 우리나라의 전통메주 발효의 주요 미생물의 하나인 Aspergillus oryzae var effuses KACC 44990로 발효시킨 메주(ASCR)와 홍국 제조용으로 사용되는 미생물의 하나인 Monascus pilosus IFO 4480으로 발효시킨 메주(MSCR) 및 이들을 1:1(w/w)로 상호 혼합한 메주(AMSCR)를 제조하였으며 이들 메주를 각 2%씩 함유하는 고지방식이로 8주간 마우스를 사육하였을 때의 체중, 혈액 및 간 조직 지질의 함량 변동과 간 조직 ROS 생성계 및 소거계 효소의 활성을 측정하였다. SCR, ASCR, MSCR 및 AMSCR은 고지방식이 또는 비만으로 유도된 간, 심장, 신장, 고환의 비대 현상과 부고환 주변 지방의 함량을 감소시키는 효과가 있으며, 그 효과는 AMSCR>ASCR>MSCR>SCR 순으로 ASCR과 AMSCR에서 높았다. SCR, ASCR, MSCR 및 AMSCR은 고지방식이 또는 비만으로 유도된 혈청과 간조직의 중성지방과 총콜레스테롤 함량을 감소시키는 효과가 있으며, 혈청의 HDL 콜레스테롤 함량을 높이면서 LDL 콜레스테롤 함량을 낮추는 효과가 있다. 특히 ASCR은 중성지방의 함량을, 그리고 MSCR은 콜레스테롤의 함량을 각각 감소시키는 효과가 높으며, ASCR과 MSCR을 혼합한 AMSCR에서 종합적인 지질개선 효과가 높았다. SCR, ASCR, MSCR 및 AMSCR은 고지방식이 또는 비만상태에서 나타나는 간 손상을 예방하는 효과가 있으며 그 효과는 AMSCR>ASCR>MSCR>SCR 순으로 컸다. SCR, ASCR, MSCR 및 AMSCR은 고지방식이 또는 비만상태에서 나타나는 ROS 생성계 효소인 XO의 활성을 억제시킴과 동시에 ROS 소거계 효소인 SOD, GPX 및 GST의 활성을 높이는 효과가 있으며 그 효과는 AMSCR>ASCR>MSCR>SCR 순으로 컸다. 결론적으로 본 실험을 통하여 발효비지는 항비만 효과가 있을 뿐만 아니라 지질을 개선할 수 있음을 확인하였다.