• Journal of Electrical Engineering and Technology
• /
• 제7권1호
• /
• pp.1-8
• /
• 2012

The current paper presents a novel control strategy of a three-phase, four-wire Unified Power Quality (UPQC) to improve power quality. The UPQC is realized by the integration of series and shunt active power filters (APF) sharing a common dc bus capacitor. The realization of shunt APF is carried out using a three-phase, four-leg Voltage Source Inverter (VSI), and the series APF is realized using a three-phase, three-leg VSI. To extract the fundamental source voltages as reference signals for series APF, a zero-crossing detector and sample-and-hold circuits are used. For the control of shunt APF, a simple scheme based on the real component of fundamental load current (I $Cos{\Phi}$) with reduced numbers of current sensors is applied. The performance of the applied control algorithm is evaluated in terms of power-factor correction, source neutral current mitigation, load balancing, and mitigation of voltage and current harmonics in a three-phase, four-wire distribution system for different combinations of linear and non-linear loads. The reference signals and sensed signals are used in a hysteresis controller to generate switching signals for shunt and series APFs. In this proposed UPQC control scheme, the current/voltage control is applied to the fundamental supply currents/voltages instead of fast-changing APF currents/voltages, thus reducing the computational delay and the required sensors. MATLAB/Simulink-based simulations that support the functionality of the UPQC are obtained.

• Asian-Australasian Journal of Animal Sciences
• /
• 제29권12호
• /
• pp.1768-1773
• /
• 2016

This experiment was conducted to determine the effect of variety and planting year on the nutritive values of corn fed to growing pigs. Four corn varieties examined in this experiment were planted in the same village located in Longhua County, Heibei Province, China, in 2012, 2013, and 2014, respectively. During each year, corn was hand-harvested in early October and sun dried to about 14% moisture content. Three batches of twenty-four barrows ($33.27{\pm}4.30$, $31.88{\pm}2.93$, $34.21{\pm}3.81kg$ body wight [BW] in 2012, 2013, and 2014, respectively) were used and allotted to a complete block design with 4 diets and 6 replicate pigs per diet. Pigs were individually placed in metabolic crates. The four experimental diets were formulated by mixing each variety of corn and vitamins and minerals, respectively. A five-day collection period followed a seven-day diet acclimation period. The results indicated that variety of corn significantly influenced the available energy content (digestible energy [DE] on dry matter basis, p<0.05; metabolizable energy (ME) on dry matter basis, p<0.05, respectively), and the apparent total tract digestibility (ATTD) of organic matter (p<0.01), dry matter (p<0.05), gross energy (p<0.05), neutral detergent fiber (p<0.01), acid detergent fiber and ether extract (p<0.05). The planting year also significantly influenced the available energy contents (DE on dry matter basis, p<0.05; ME on dry matter basis, p<0.01, respectively) and the ATTD of neutral detergent fiber (p<0.01), acid detergent fiber (p<0.01), crude protein (p<0.01), and ether extract (p<0.01). No interaction was observed between the variety and planting year in DE and ME contents in corn. In conclusion, the variety and planting year significantly influenced the available energy and nutrient digestibility of corn fed to growing pigs.

• 미생물학회지
• /
• 제50권4호
• /
• pp.360-367
• /
• 2014

Candida albicans는 면역력이 약화된 환자의 표재성에서 전신적 감염까지 다양한 부위에서 감염을 유발시킬 수 있는 기회 감염적 병원성 진균이다. C. albicans는 효모형에서 균사형으로 변환될 수 있으며 이 때 바이오필름을 형성할 수 있다. 바이오필름과 관련된 C. albicans의 감염은 일반적으로 통상적인 항진균제에 대해 내성을 보이므로 새로운 항진균제에 대한 개발이 절실하다. 대황(Rheum undulatum)은 전통적으로 한국과 중국에서 하제나 소염제로 사용되는 약용 식물이다. 본 연구의 목적은 R. undulatum이 캔디다증 환자로부터 분리한 C. albicans 바이오필름 형성 균주에 대한 바이오필름 형성 억제효과와 이에 대한 항진균 활성 기작을 알아보는 것이다. R. undulatum (0.098 mg/ml)은 12종의 바이오필름 형성 임상균주의 캔디다 바이오필름을 $49.4{\pm}6.0%$ 감소시켰고 C. albicans의 폴리스티렌 표면으로의 부착을 억제시켰다. CFDA, AM과 propidium iodide로 이중 염색한 결과 R. undulatum은 C. albicans의 세포막을 손상시켰으며 propidium iodide와 neutral red로 염색하여 공초점 레이저 현미경과 위상차 현미경으로 관찰한 결과 C. albicans의 세포용해를 야기함을 관찰할 수 있었다. Crystal violet 흡수율 실험으로 R. undulatum에 의한 세포막 투과성의 변화를 관찰하였다. 따라서 R. undulatum은 세포막의 손상과 세포막의 투과성 변화로 야기된 세포의 용해와 관련된 항진균 활성이 C. albicans의 바이오필름 형성을 억제하는 것으로 보여진다. 본 연구의 결과는 R. undulatum이 바이오필름과 관련된 캔디다의 감염을 치료하고 제거하기 위한 천연물 기반 항진균제 개발에 대한 좋은 후보물질임을 보여준다.

• Journal of Microbiology and Biotechnology
• /
• 제24권1호
• /
• pp.26-35
• /
• 2014

Saccharothrix algeriensis NRRL B-24137 produces naturally different dithiolopyrrolone derivatives. The enzymatic activity of pyrrothine N-acyltransferase was determined to be responsible for the transfer of an acyl group from acyl-CoA to pyrrothine core. This activity was also reported to be responsible for the diversity of the dithiolopyrrolone derivatives. Based on this fact, nine dithiolopyrrolone derivatives were produced in vitro via the crude extract of Sa. algeriensis. Three of them have never been obtained before by natural fermentation: acetoacetyl-pyrrothine, hydroxybutyryl-pyrrothine, and dimethyl thiolutin (holomycin). Two acyltransferase activities, acetyltransferase and benzoyltransferase catalyzing the incorporation of linear and cyclic acyl groups to the pyrrothine core, respectively, were biochemically characterized in this crude extract. The first one is responsible for formation of acetyl-pyrrothine and the second for benzoyl-pyrrothine. Both enzymes were sensitive to temperature changes: For example, the loss of acetyltransferase and benzoyltransferase activity was 53% and 80% respectively after pre-incubation of crude extract for 60 min at $20^{\circ}C$. The two enzymes were more active in neutral and basal media (pH 7-10) than in the acidic one (pH 3-6). The optimum temperature and pH of acetyltransferase were $40^{\circ}C$ and 7, with a $K_m$ value of $7.9{\mu}M$ and a $V_{max}$ of $0.63{\mu}M/min$ when acetyl-CoA was used as limited substrate. Benzoyltransferase had a temperature and a pH optimum at $55^{\circ}C$and 9, a $K_m$ value of $14.7{\mu}M$, and a $V_{max}$ of $0.67{\mu}M/min$ when benzoyl-CoA was used as limited substrate.

• 문화기술의 융합
• /
• 제9권1호
• /
• pp.725-733
• /
• 2023

천연물 16종의 물 추출물 및 50% 에탄올 추출물들에 대한 기능성 활성성분 및 면포 염착효과를 알아본 결과, 색도 강도는 차이가 있었으나 적색 6종, 황색 5종, 오렌지색 2종 및 녹색 3종 이었고, 대체로 50% 에탄올 추출액의 색도가 높고 선명하였다. 이와 같은 천연물들의 물 추출물 및 50% 에탄올 추출물에 면포 거즈를 2일간 침지하여 염색한 결과 염색효과는 대체로 양호하였으며, 실온에서 건조 후 개봉하여 보관하여도 색도의 퇴색 감소는 거의 없는 것으로 관찰되었다. 천연물 16종의 물추출물의 pH는 중성 내지는 약산성으로 피부에 부작용이 없는 중성~약산성 범위였다. DPPH 유리라디칼 억제 항산화효과는 시료 별로 50% 에탄올 추출물의 효과가 물추출물에 비하여 양호하였고, 특히 황금, 유백피, 유근피, 박하, 홍화 등의 효과가 양호하였다. 폴리페놀 함량도 대체로 50% 에탄올 추출물의 함량이 물 추출물에 비하여 높은 경향이었고, 특히 금은화, 유근피, 황금, 유백피, 홍화 등의 효과가 양호하였다. 따라서 천연물 16종 추출물에 대한 항산화 활성과 여성질염 예방의 상관 관계를 규명하고자 하였다.

• 한국식품영양과학회지
• /
• 제22권4호
• /
• pp.412-417
• /
• 1993

녹각이 동양의학에서 보혈강장제라는 사실에 근거하여 생체내 물질대사에 중요한 역할을 하는 간장의 장해시 효소활성 변동에 미치는 녹각의 효능을 구명할 목적의 일환으로 간독성 물질인 benzo(a)pyrene으로 간장해를 유도한 후 각각의 녹각추출물을 급여함으로써 간해독 과정에 관여하는 효소의 활성을 생화학적 측면에서 비교하였다. 각각의 녹각추출물 급여로 인한 체중증가량, 식이섭취량 및 식이효율은 녹각추출물 군간의 유의성은 나타나지 않았으나, Control군에 비하여 유의적인 증가를 보였고 B(a)P 투여군에서도 Cont-B군에 비하여 녹각추출물 급여군에서 유의적인 증가를 나타내었다. 체중 100g당 장기무게는 간장의 경우 benzo (a)pyrene 투여로 증가하는 경향을 보였으나 비장과 신장 및 심장에는 별다른 차이가 없었다. 녹각추출물 급여로 4주간 사육한 흰쥐에서 간해독계 효소중 cytochrome P-450의 함량은 Control 군에 비하여 ben-zo(a)pyrene 투여로 유의적인 감소를 보였으며, 녹각추출물과 benzo(a)pyrene을 병행 투여한 실험군 중 Water-B군이 정상군에 가깝게 증가되었다. 간조직 중의 glutathione함량은 Water군과 Neutral군에서 증가를 보였으나 benzo(a)pyrene 투여로 감소하였다. 또한 간조직 중의 glutathione peroxidase 활성은 녹각추출물 급여에 따른 영향은 없었으며, benzo(a)pyrene 투여로 감소된 활성이 water-B군에서 정상군에 가까운 증가를 나타내었다. 간조직 중의 과산화지질 함량은 Water-B군에서 그 감소 정도가 가장 현저하였다. 이상의 결과를 종합해 볼 때 녹각추출물 중의 water-ext.와 neutral-ext.에 함유되어 있는 유효성분이 간장의 해독기구 효소활성을 유도하고, benzo(a)pyrene의 대사를 촉진시키므로 간손상을 억제할 수 있을 것으로 생각된다.

• Parasites, Hosts and Diseases
• /
• 제27권3호
• /
• pp.161-170
• /
• 1989

Toxeplasma의 추출액을 3H-casein을 기질로 반응시켰을 때, pH 6.0과 PH 8.5에서 casein을 분해하였으며, pH 6.0에서는 cysteinyl protease의 억제제 인 iodoacetamide(rAh)에 의해 억제되 었고, 활성제 인 dithiothreitol (DTT)에 의해 환성이 증가하였다. 또 pH 8.5에서는 serine protease의 억제제인 phenylmethylsulfonil fluoride (PMSF)에 의해 활성이 억제되었으며, ATP를 첨가할 때 그 활성이 증가하여 ATP 의존성 효소임을 알 수 있었다. 위의 단백질 분해 효소를 부분 정제하기 위해 여러 chromatography를 실시하였는데, 먼저 DE52 (2.Sfx40 cm)에 통과시켰을 때, 0.05M-0.IM NaCl에 의해 유출되는 분획이 pH 6.0에서 황성을 나타내었으며, 0.25V- 0.3M에서 유출되는 분획이 pH 8.5에서 황성을 나타내었다. 이 분회들을 각각 Sephadex G-200 ($2.50{\phi}{\times}40cm$) 에 통과시켜 pH 6.0에서 활성을 나타내는 분획은 exclusion limit내에서, pH 8.5의 분획은 exclusion limit 외에서 분획을 얻었다. 이들을 각각 hydroxylapatite ($2.50{\phi}{\times}10cm$과 $2.5{\phi}{\times}20cm$)를 통과시켜 각각을 0.05M Phosphate로 유출되는 분회에서 높은 환성을 얻었다. 부분 정제된 분획들의 특성을 검토하기 위하여 억제제를 농도별로 처리하였을 때, pH 0.0에서의 분해 효소는 10-3M IAA에 의해 활성이 반감되어 cysteinyl acid protease임을 알 수 있었다. pH 8.5에서의 분해 효소는 10-5M PMSF에 의해 활성이 반감되었고, ATP에 의해 활성이 증가(ATP의 농도가 2.0mM 이상에서는 억제)하여 ATP-dependent neutral serine protease임을 알 수 있었다.

• Nutritional Sciences
• /
• 제6권3호
• /
• pp.141-147
• /
• 2003

Fruits and vegetables reportedly have a protective effect against hyperlipidemia and oxidative disease. Accordingly, this study aimed to investigate the lipid-lowering effect and antioxidative capacity of persimmon leaf extract (PLE) in rats fed a high-cholesterol diet. Male rats were fed a high-cholesterol (1% wt/wt) or high-cholesterol diet supplemented with Lovastatin (0.02% wt/wt) or PLE (0.2% wt/wt) for 5 weeks. The concentration of plasma total cholesterol was significantly lower in the PLE group than in the lovastatin group. However, the concentration of plasma HDL-cholesterol and the ratio of HDL-cholesterol/total-cholesterol (%) were significantly higher in the PLE group than in the control group. The PLE supplement also significantly lowered the contents of hepatic cholesterol and triglyceride. In comparing fecal sterol contents, the PLE group saw a significant increase of both neutral and acidic sterol compared to the other groups. The PLE supplement significantly lowered plasma GOT and GPT activity, which ave indices of hepatic toxicity. Plasma TBARS concentration was significantly lower in the PLE group than in the control group, while hepatic TBARS level was not significantly different between the groups. In a comparison of hepatic antioxidant parameters, SOD, catalase and GSH-Px activity were significantly higher in the PLE group than in the control group. However, the PLE supplement significantly towered antioxidant enzyme activity in the erythrocyte. Furthermore, these results suggest that supplementation of PLE promoted the excretion of fecal sterols, thereby leading to decreased absorption of dietary cholesterol. In addition, PLE may play an important role in regulating antioxidative capacities by altering SOD and ChT activity.

• 한국토양비료학회지
• /
• 제14권3호
• /
• pp.130-136
• /
• 1981

Rice hull was reduced to ash by carbonization grades to illcuidate alkalinity increase and extract of inorganic nutrients in the rice hull charcoal. Alkaline reaction of water extraction was neutral at less carbonized charcoal, but much carbonized ash from 65% weight loss reached over 10 of pH value, also origin shape of rice hull was maintained until near 65% carbonized grade. Therefore, physical properties sustained good condition for seedling bed. The more charcoal carbonized to ash, the pH value and concentration of inorganic nutrient in their extracts were increased gradually. Nitric acid concentrations for neutralizing extract from charcoal were stronger in proportion to the carbonized grade but 0.1 N nitric acid solution was very reasonable to neutralize the 65% carbonized charcoal for mixing with heavy texture acidy soil(pH 5.3) of uncultivated deep horizon to transplant the tobacco seedlings. Volume ratio mixing for seedling bed is adequate at five of ash to one of acid solution. Neutralization with nitric acid solution also accelerated extraction of the inorganic nutrient in rice hull ash. Tobacco seedlings grown on bed mixed with neutralized rice hull charcoal and soil had shown better results on the agronomic measurement than alkaline ash bed, and phosphorus and cations were uptaken more amounts.

• 생약학회지
• /
• 제25권3호
• /
• pp.249-257
• /
• 1994

The cytotoxic and antitumor activity of Perilla frutescens extract on cultured 3T3 fibroblast and skin melanoma cells were evaluated by tetrazolium MTT (MTT) and neutral red (NR) colorimetric assay methods. Lactate dehydrogenase activity was also measured. The light microscopic study was carried out to observe morphological changes of cultured mouse fibroblast and skin melanoma cells. The results were as follows: 1. Water and ether extracts showed a significant cytotoxicity in 3T3 fibroblast and all extracts exhibited a significant anti-tumor activity in skin melanoma cells. Methanol, ethyl acetate and ethanol extracts showed low cytotoxic effects, but exhibited a high anti-tumor activity. 2. The MTT absorbance in 3T3 fibroblast was significantly decreased by treatment with ether, water, chloroform and ethanol extracts and skin melanoma cells was significantly decreased by treatment with all extracts. The difference in MTT absorbance in two cell types was most remarkable when treated with methanol and ethanol extracts. 3. Methanol and ethyl acetate extracts showed the strongest effect in growth inhibition of melanoma cells. These results indicated that methanol extract possessed a low cytotoxicity and a strong anti-tumor activity.