• Nutrition Research and Practice
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• 제16권2호
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• pp.147-160
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• 2022

BACKGROUND/OBJECTIVES: Patients with chronic kidney disease (CKD) have a high concentration of uremic toxins in their blood and often experience muscle atrophy. Indoxyl sulfate (IS) is a uremic toxin produced by tryptophan metabolism. Although an elevated IS level may induce muscle dysfunction, the effect of IS on physiological concentration has not been elucidated. Additionally, the effects of ursolic acid (UA) on muscle hypertrophy have been reported in healthy models; however, it is unclear whether UA ameliorates muscle dysfunction associated with chronic diseases, such as CKD. Thus, this study aimed to investigate whether UA can improve the IS-induced impairment of mitochondrial biogenesis. MATERIALS/METHODS: C2C12 cells were incubated with or without IS (0.1 mM) and UA (1 or 2 μM) to elucidate the physiological effect of UA on CKD-related mitochondrial dysfunction and its related mechanisms using real-time reverse transcription-polymerase chain reaction, western blotting and enzyme-linked immunosorbent assay. RESULTS: IS suppressed the expression of differentiation marker genes without decreasing cell viability. IS decreased the mitochondrial DNA copy number and ATP levels by downregulating the genes pertaining to mitochondrial biogenesis (Ppargc1a, Nrf1, Tfam, Sirt1, and Mef2c), fusion (Mfn1 and Mfn2), oxidative phosphorylation (Cycs and Atp5b), and fatty acid oxidation (Pdk4, Acadm, Cpt1b, and Cd36). Furthermore, IS increased the intracellular mRNA and secretory protein levels of interleukin (IL)-6. Finally, UA ameliorated the IS-induced impairment in C2C12 cells. CONCLUSIONS: Our results indicated that UA improves the IS-induced impairment of mitochondrial biogenesis by affecting differentiation, ATP levels, and IL-6 secretion in C2C12 cells. Therefore, UA could be a novel therapeutic agent for CKD-induced muscle dysfunction.

• Journal of Nutrition and Health
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• 제39권3호
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• pp.244-251
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• 2006

The purpose of this study was to observe the effects of cellulose and pectin on glucose and plasma lipid concentrations in healthy women. Eight female collage students were participated voluntarily. All subjects received a fiber-free control diet (CD), cellulose diet (CED), pectin diet (PTD) with each diet for a period of three days with a 4 day interval. The food intake of subjects were monitored every day and plasma level of glucose, triglyceride, total cholesterol were determined at last day. Blood glucose, plasma triglyceride, total cholesterol were measured at fasting state and 30, 60, 90, 120, and 180 minute after consuming each diet. Plasma glucose concentrations (AUC: Area Under the Curve) of pectin diet was $122.7{\pm}4.0mg/dl$ and that of cellulose diet was $147.6{\pm}8.4mg/d$, but they were significantly lower than in comparison with those of control diet ($197.1{\pm}11.6mg/dl$) (p<0.05) Plasma triglyceride concentrations of the CED ($-83.9{\pm}22.2mg/dl$) PTD ($-9.7{\pm}26.1mg/dl$) showed gradual decrease after each test diet feeding but not significantly different in each dietary fiber added diet (p<0.05). Plasma cholesterol concentrations of the CD was not significantly different in PTD, but PTD was significantly lower than the CED until 3 hours after consuming each test meal (p<0.05). In conclusion, in spite of total cholesterol was reduced only by pectin, glucose and triglyceride were lower than control diet in dietary fiber intake. But there were no significant differences each dietary fiber.

• 전자공학회논문지
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• 제52권1호
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• pp.140-147
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• 2015

본 연구는 의료기기법이 시행된 이래 의료기기 부작용등 안전성 정보관리를 위한 의료기기 안전성 정보 원내 보고 시스템 설계에 대한 연구이다. 본 연구는 현행 의료기기 부작용등 안전성정보 보고 관리에 대한 법적 규정 및 시스템에 대한 절차와 현황을 파악하고, MSF/CD(Microsoft Solution Framework/Component Design)설계방법론을 적용한 시스템 설계 방법을 적용하여 의료기기 안전성 정보 원내 보고 시스템 구축을 위한 설계를 하였다. 본 연구를 통해 우리나라의 부작용 등 안전성 정보 보고에 대한 식품의약품안전처 고시 규정을 포함한 의료기기 관리 제도를 파악하고, 좀 더 환자의 안전과 의료기기의 위험관리를 효과적으로 할 수 있는 의료기기 안전성 정보 원내 보고 시스템을 설계 및 구축함으로써 의료기기 부작용 등 안전성 정보 보고의 활성화에 이바지 할 수 있기를 기대한다.

• Spatial Information Research
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• 제7권1호
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• pp.147-153
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• 1999

지질도와 지질자료는 국토이용계획, 자원개발, 지질재해 예방 환경오염 방지 및 교육 등 다양한 용도로 활용되고 있는 중요한 정보이나 이들에 대한 데이터베이스화는 아직 본격적으로 수행되지 않고 있어 방대한 양의 지질자료가 체계적으로 관리되지 못해 정보로서의 이용가치와 효용성이 떨어진다. 또한 지질도는 층서 체계의 미확립, 도면 보존 및 경계 일치의 문제점 등 많은 문제점을 가지고 있어 데이터베이스 구축에 많은 문제점이 있으나 국가 기본 주제도의 하나로 빠른 시일 내에 데이터베이스로 구축되어야 한다. 본 연구에서는 지질도 데이터베이스 구축 및 활용을 위해 1:50,000 축척의 안성 지질도, 1:250,000 축척의 부산 지질도 1:25,000 축척의 남창 지질도, 1:1,000,0000 축척의 한국 지질도 등을 시범지역으로 선정하여 이 지역에 대해 지리정보시스템(GIS)을 이용해 데이터베이스 설계 및 구축을 하였다. 또한 구축된 데이터베이스를 관리할 수 있는 관리 프로그램은 GIS 프로그램을 이용해 개발하였고, 구축된 데이터베이스를 이용하여 수치지질도 제작 및 인터넷과 CD를 통한 자료 제공 등을 구현하였다.

• 한국지하수토양환경학회지:지하수토양환경
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• 제8권2호
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• pp.19-35
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• 2003

In order 새 investigate the spatial and seasonal variations of heavy metal pollution in heavily industrialized urban area, urban roadside sediments were collected for five years from gully pots in Seoul City. A series of studies have been carried out concerning the physicochemical characteristics of the sediments in order to evaluate the contamination of heavy metals such as Cd, Co, Cr, Cu, Ni, Pb and Zn. Roadside sediments and uncontaminated stream sediments were analyzed for total metal concentrations using acid extraction. The roadside sediments are characterized by very high concentrations of Zn (2,665.0$\pm$1,815.0 $\mu\textrm{g}$/g), Cu (445.6$\pm$708.0 $\mu\textrm{g}$/g), Pb (214.3$\pm$147.9 $\mu\textrm{g}$/g) and Cr (182.1$\pm$268.8 $\mu\textrm{g}$/g), indicating an artificial accumulation of these metals to the sediment chemistry. Comparing with average contents of uncontaminated stream sediments, roadside sediments were shown zinc 14 times (up to 64.4), copper 9 times (up to 181.7), lead 6 times (up to 63.7), cobalt 6 times (up to 168.7), nickel 4 times (up to 98.4), cadmium 2 times (up to 12.8) and chrome 2 times (up to 40.2) high content. The relative degree of heavy metal pollution for roadside sediments collected from each district in Seoul City is evaluated using the “geoaccumulation index”. As a result, heavy-metal contamination is highest centering the oldest residential district and industry area, and contamination level decreases as go to outer block of the city. The factor analysis results indicate that the levels of Cu, Ni, Fe and Cr are strongly related to numbers of factories, whereas the concentrations of Cr, Zn and Cd dependant on pollution index, indicating artificial contamination due to site-specific traffic density.

• 디지털융복합연구
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• 제12권3호
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• pp.269-275
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• 2014

Eureka 147 디지털오디오방송(DAB) 시스템은 CD 품질의 오디오 전송을 위하여 유럽에서 개발되었으나 한국에서는 이러한 DAB 시스템을 기반으로 하여 오디오뿐 만 아니라 비디오 신호도 전송할 목적으로 지상파 디지털 멀티미디어방송(T-DMB) 시스템을 개발하였다. 이러한 T-DMB 시스템의 성능 향상을 목적으로 본 논문에서는 양립성을 위해 기존 T-DMB 시스템 표준안에 정의된 펑쳐링 절차와 평처링 벡터를 이용하면서 터보 부호가 적용된 2가지 형태의 새로운 터보부호화된 T-DMB 시스템 모델을 제시한다. 첫 번째 모델 (Type 1)은 기존의 RS 코드, 콘볼류션 인터리빙, RCPC 코드를 터보코드로 대체시킨 것이며 두 번째 모델(Type 2)은 기존 RCPC 만을 터보부호로 대체시킨 모델이다. 시뮬레이션 결과 제안된 모델은 단지 2회 반복만으로도 상당한 성능 향상을 얻을 수 있음을 알 수 있었으며 또한 두 번째 모델은 첫 번째 모델에 비해 약간 우수한 성능을 보이고 있다.

• Bulletin of the Korean Chemical Society
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• 제29권1호
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• pp.139-147
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• 2008

New PPV derivatives which contain electron-withdrawing CF3F4phenyl group, poly[2-(2-ethylhexyloxy)-5-(2,3,5,6-tetrafluoro-4-trifluoromethylphenyl)-1,4-phenylenevinylene] (CF3F4P-PPV), and poly[2-(4-(2-etylhexyloxy)-phenyl)-5-(2,3,5,6-tetrafluoro-4-trifluoromethylphenyl)-1,4-phenylenevinylene] (P-CF3F4P-PPV), have been synthesized by GILCH polymerization. As the result of the introduction of the electron-withdrawing CF3F4phenyl group to the phenyl backbone, the LUMO and HOMO energy levels of CF3F4P-PPV (3.14, 5.50 eV) and P-CF3F4P-PPV (3.07, 5.60 eV) were reduced. The PL emission spectra in solid thin film are more red-shifted over 50 nm and increased fwhm (full width at half maximum) than solution conditions by raising aggregation among polymer backbone due to electron withdrawing effect of 2,3,5,6-tetrafluoro-4-trifluoromethylphenyl group. The EL emission maxima of CF3F4P-PPV and P-CF3F4P-PPV appear at around 530-543 nm. The current density-voltage-luminescence (J-V-L) characteristics of ITO/PEDOT/polymer/Al devices of CF3F4P-PPV and P-CF3F4P-PPV show that turn-on voltages are around 12.5 and 7.0 V, and the maximum brightness are about 82 and 598 cd/m2, respectively. The maximum EL efficiency of P-CF3F4P-PPV (0.51 cd/A) was higher than that of CF3F4P-PPV (0.025 cd/A).

• 대한전기학회:학술대회논문집
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• 대한전기학회 2008년도 심포지엄 논문집 정보 및 제어부문
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• pp.83-85
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• 2008

현행 지상파 DMB(Digital Multimedia Broadcasting)에서는 최대 CIF급 해상도의 동영상을 384 Kbps 정도의 비트율로 압축하여 비디오 CD급의 화질을 제공한다. 따라서 큰 화면을 통해 DMB 방송을 시청할 경우 해상도 부족 등으로 인한 화질 열화를 느낄 수 있다. 이와 같은 문제를 해결하기 위한 방안으로 계층적으로 부호화된 비트스트림을 서로 다른 채널로 전송하는 고품질 AT-DMB 시스템이 연구되고 있다. 더불어, 계층변조 기술을 이용하여 추가적인 전송대역폭을 확보하고, 계층적 비디오 부호화 기술을 이용하여 고품질 이동 멀티미디어 방송을 제공하는 고품질 T-DMB 방식이 개발되고 있다. 이와 같은 AT-DMB 방식으로 사용자에게 안정된 고품질 비디오 서비스를 제공하기 위해서는 계층적 비디오 부호화를 고려한 효율적인 AV다중화 및 동기화 구조에 대한 연구가 필수적으로 요구 된다. 본 논문에서는, 이와 같은 고품질 AT-DMB 시스템을 위해서 각 계층 ES(Elementary stream)을 MPEG-4 over MPEG-2 시스템과 Eureka-147 DAB 시스템을 통해 서로 다른 채널로 전송한다. 계층별 전송으로 인한 시간 지연에 대처하여 수신입력부에서는 각각의 계층으로 전송된 ES들이 동기화 되어 복호화 되도록 SVC의 계층적 비트스트림 구조와 적응적으로 동작되는 다중화 시스템구조를 제작하였다.

• 한국광물학회지
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• 제10권2호
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• pp.139-147
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• 1997

The Janghang smelter is the first lead, zinc and copper smelting facility in Korea which was operated for a half century from 1936 to 1989. The clay minerals and their heavy metal association in the soil profile around the smelter have been studied using XRD, EPMA, SEM-EDS, TEM, EPR and sequential extraction techniques. The soils in A horizon are highly acidic showing pH 4.45. The pH is going up with increasing depth. They have residual water contents of 1.18-1.51 wt%, loss on ignition of 6.32-7.79 wt%, and carbon contents of 0.08-0.88 wt%. Soils consist of quartz, feldspar, muscovite, kaolinite, vermiculite, biotite, chlorite, goethite and hematite in the decreasing abundance. The contents of clay minerals, especially vermiculite and chlorite, decrease with increasing depth. Sequential extraction experiments for the profile samples show that heavy metals (Zn, Cu, Pb, Cd) are highly concentrated in the A horizon of the soil profile as water-extractable (mostly amorphous), MgCl2-extractable (exchangeable in clay minerals), and organic phases. The heavy metal contents decrease with increasing depth. It suggests that the heavy metals are mainly associate with clay minerlas in an exchangeable state. It is also noted that heavy metals are highly concentrated in the manganese and iron oxide phases.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2007년도 추계학술대회 논문집
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• pp.147-151
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• 2007

A serpentine channel geometry often used in a polymer electrolyte membrane fuel cell has a strong pressure gradient between adjacent channels in specific regions. The pressure gradient helps some amount of reactant gas penetrate through a gas diffusion layer(GDL). As a result, the overall serpentine flow structure is slightly different from intention of a designer. The purpose of this paper is to examine the effect of serpentine flow structure on current density distribution. By using a commercial code, STAR-CD, a numerical simulation is performed to analyze the fuel cell with relatively high aspect ratio active area. To increase the accuracy of the numerical simulation, GDL permeabilities are measured with various compression conditions. Three-dimensional flow field and current density distribution are calculated. For the verification of the numerical simulation results, water condensation process in the cathode channel is observed through a transparent bipolar plate. The result of this study shows that the region of relatively low current density corresponds to that of dropwise condensation in cathode channels.