• 대한방사선기술학회지:방사선기술과학
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• 제35권4호
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• pp.353-360
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• 2012

핵의학 영상 기기 중 SPECT시스템은 촬영목적에 따라 다양한 콜리메이터를 사용하며 영상 재구성을 위해서는 각 콜리메이터의 기하학적 특성을 반영하는 것이 필요하다. 본 연구에서는 이 중 핀홀 콜리메이터를 사용한 핵의학 영상기기의 영상 재구성에 관한 연구를 수행하였으며 특히 핀홀 콜리메이터 영상 재구성시 발생하는 샘플링 문제를 제거하는 방법에 대한 연구를 수행하였다. 순환적 영상 재구성 방법의 투사(projection)와 역투사(back-projection)시 각기 다른 방식으로 구축된 시스템 모델을 반영한 비동일 시스템 모델 방식을 개발하여 최대우도 기댓값최대화(maximum likelihood expectation maximization, ML-EM) 알고리듬에 적용하였다. 설계한 재구성 알고리듬을 성능을 검증하기 위해 geant4 application for tomographic emission(GATE) 시뮬레이션 툴을 이용하여 핀홀 콜리메이터의 디지털 팬텀 시뮬레이션을 수행하고 이를 이용하여 기존방식과 제안한 방식의 재구성 알고리듬에 대한 비교평가 연구를 수행하였다. 그 결과 본 연구에서 제안한 비동일 시스템 모델 사용 영상 재구성 방법은 동일 시스템 모델을 사용한 순환적 재구성 알고리듬에 비해 효과적으로 샘플링 문제를 제거할 수 있는 것을 확인 할 수 있었다. 본 연구에서 제안한 영상 재구성 방법은 다양한 콜리메이터에 확대적용 되어 사용 될 수 있을 것으로 기대된다.

• 대한화장품학회:학술대회논문집
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• 대한화장품학회 2003년도 IFSCC Conference Proceeding Book II
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• pp.108-109
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• 2003

Ursolic acid (UA) and Oleanolic acid (ONA), known as urson, micromerol, prunol and malol, are pentacyclic triterpenoid compounds which naturally occur in a large number of vegetarian foods, medicinal herbs, and plants. They may occur in their free acid form or as aglycones for triterpenoid saponins, which are comprised of a triterpenoid aglycone, linked to one or more sugar moieties. Therefore UA and ON A are similar in pharmacological activity. Lately scientific research, which led to the identification of UA and ONA, revealed that several pharmacological effects, such as antitumor, hepatoprotective, anti-inflammatory, antimicrobial, and anti-hyperlipidemic could be attributed to UA and ONA. Here, we introduced the effects of UA and ONA on acute barrier disruption and normal epidermal permeability barrier function. To clarify the effects of UA and ONA on skin barrier recovery, both flank skin of 8-12 weeks hairless mice were topically treated with samples (2mg/ml) after tape stripping, then measured recovery rate using TEWL on hairless mice. The recovery rate increased in UA and ONA treated groups at 6h more than 20% compared to vehicle treated group (p <0.05). For verifying the effects of UA and ONA on normal epidermal barrier, hydration and TEWL were measured for 1 and 3 weeks after UA and ONA applications (2mg/ml per day). We also investigated the features of epidermis and dermis using electron microscopy (EM) and light microscopy (LM). Both samples increased hydration compared to Vehicle group from 1 week without TEWL alteration (p<0.005). EM examination using Ru04 and OsO4 fixation revealed that secretion and numbers of lamellar bodies and complete formation of lipid bilayers were most prominent (ONA$\geq$UA>Vehicle). LM finding showed that stratum corneum was slightly increased and especially epidermal thickening and flattening was observed (UA>ONA>Vehicle). Using Masson-trichrome and elastic fiber staining, we observed collagen thickening and elastic fiber increasing by UA and ONA treatments. In vitro results of collagen and elastin synthesis and elastase inhibitory experiments were also confirmed in vivo findings. This result suggested that the effects of UA and ONA related to not only skin barrier but also collagen and elastic fibers. Taken together, UA and ONA can be relevant candidates to improve barrier function and pertinent agents for cosmetic applications.

• 대한화장품학회지
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• 제29권2호
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• pp.205-232
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• 2003

Ursolic acid (UA) and Oleanolic acid (ONA), known as urson, micromerol and malol, are pentacyclic triterpenoid compounds which naturally occur in a large number of vegetarian foods, medicinal herbs, and plants. They may occur in their free acid form or as aglycones for triterpenoid saponins, which are comprised of a triterpenoid aglycone, linked to one or more sugar moieties. Therefore UA and ONA are similar in pharmacological activity. Lately scientific research, which led to the identification of UA and ONA, revealed that several pharmacological effects, such as antitumor, hepato-protective, anti-inflammatory, anticarcinogenic, antimicrobial, and anti-hyperlipidemic could be attributed to UA and ONA. Here, we introduced the effect of UA and ONA on acutely barrier disrupted and normal hairless mouse skin. To evaluate the effects of UA and ONA on epidermal permeability barrier recovery, both flanks of 8-12 week-old hairless mice were topically treated with either 0.01-0.1 mg/ml UA or 0.1-1 mg/ml ONA after tape stripping, and TEWL (Transepidermal water loss) was measured . The recovery rate increased in those UA or ONA treated groups (0.1 mg/ml UA and 0.5 mg/ml ONA) at 6 h more than $20\%$ compared to vehicle treated group (p<0.05). Here, we introduced the effects of UA and ONA on acute barrier disruption and normal epidermal permeability barrier function. For verifying the effects of UA and ONA on normal epidermal barrier, hydration and TEWL were measured for 1 and 3 weeks after UA and ONA applications (2mg/ml per day). We also investigated the features of epidermis and dermis using electron microscopy (EM) and light microscopy (LM). Both samples increased hydration compared to vehicle group from f week without TEWL alteration (p<0.005). EM examination using RuO4 and OsO4 fixation revealed that secretion and numbers of lamellar bodies and complete formation of lipid bilayers were most prominent $(ONA{\geq}UA>Vehicle)$. LM finding showed that thickness of stratum corneum (SC) was slightly increased and especially epidermal thickening and flattening was observed (UA>ONA>Veh). We also observed that UA and ONA stimulate epidermal keratinocyte differentiation via $PPAR\;\alpha$. Protein expression of involucrin, loricrin, and filaggrin increased at least 2 and 3 fold in HaCaT cells treated with either $ONA\;(10{\mu}M)$ or UA $(10{\mu}M)$ for 24h respectively. This result suggested that the UA and ONA can improve epidermal permeability barrier function and induce the epidermal keratinocyte differentiation via $PPAR\;{\alpha}$. Using Masson-trichrome and elastic fiber staining, we observed collagen thickening and elastic fiber elongation by UA and ONA treatments. In vitro results of collagen and elastin synthesis and elastase inhibitory activity measurements were also confirmed in vivo findings. These data suggested that the effects of UA and ONA related to not only epidermal permeability barrier functions but also dermal collagen and elastic fiber synthesis. Taken together, UA and ONA can be relevant candidates to improve epidermal and dermal functions and pertinent agents for cosmeseutical applications.

• Journal of Nutrition and Health
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• 제39권5호
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• pp.476-484
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• 2006

To elucidate the relationship between blood parameters related bone metabolism and antioxidant enzyme activity in postmenopausal period 60 women residing in Iksan area were recruited. Food and nutrient intake of each individual subject were estimated by 24-hour recalls of 3 non-consecutive days. The biochemical markers including total protein, albumin, osteocalcin (intact bone gla protein; BOP), calcium, phosphorus and hemoglobin were measured in fasting blood. In addition, parameters of antioxidative capacity including the activities of superoxide dismutase (SOD), glutathione peroxidase (GPx) , catalase (CAT) and total antioxidant capacity (TA) were monitored in blood, also. The mean age, height, weight, and BM! of subjects were 64.8 years, 151.1 em, 59.5 kg $26.0\;kg/m^2$, respectively. The mean SOD, GPx, and CAT activities were 138.5 U/ml, 1,273.8 U/ml and 314.3 kU/l respectively, and TA was 1.16 mmol/l without significant difference among different age groups. BMI was positively correlated with SOD activity (p < 0.01). SOD activity and CAT activity showed positive correlation with serum albumin (p < 0.05) and hemoglobin (p < 0.01). In conclusion, this study revealed that antioxidant enzyme activity holds a significant relationship with the blood parameters like as serum albumin and hemoglobin in postmenopausal women and further systematic research is needed to investigate the their relation mechanism.

• 한국동물위생학회지
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• 제32권3호
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• pp.281-286
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• 2009

Fluoroquinolones in muscle and egg were separated by liquid extraction and determined. The analysis was carried out using following conditions; C18 column ($150{\times}4.6mm$, $5{\mu}m$), mobile phase composed of D.W. (containing 0.4% triethylamine and phosphoric acid) : methanol : acetonitrile (780:100:120, v/v/v), quarternary pump at a flow rate of 0.9ml/min and $20{\mu}l$ of injection volume, fluorescence detector with EX 278nm/Em 456nm. The calibration range of seven fluoroquinolones showed linearity ($r^2{\geq}0.999$) at concentration range of $0.025{\sim}0.8{\mu}g/ml$. The recoveries in fortified muscle and egg represented more than 81.3%. The detection limits for ofloxacin, norfloxacin, ciprofloxacin, enrofloxacin, danofloxacin, saraloxacin and orbifloxacin were 3.1, 2.5, 3.6, 1.7, 0.9, 2.5 and $2.1{\mu}g/kg$, respectively. We also monitored fluoroquinolones residue in the sample (chicken muscle 182, cattle muscle 140, pig muscle 139, egg 212) using EEC-plate (E. coli ATCC 11303) screening and HPLC confirmation methods. The screening test results, fluoroquinolones, antibacterial substances were all negative.

• 한국생물공학회:학술대회논문집
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• 한국생물공학회 2005년도 생물공학의 동향(XVII)
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• pp.651-654
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• 2005

10 g/L yeast extract, 20 g/L peptone, 20 g/L dextrose가 첨가된 YPD 배지를 이용하여 200 rpm, 30 $^{\circ}C$에서 24시간 배양한 Pichia pastoris X-33과 KM71H를 각각 대수 증식기에 시료를 채취하여 4000 g, 4 $^{\circ}C$에서 5분간 원심분리하여 펠릿만을 얻어 멸균된 증류수를 500 ${\mu}{\ell}$ 넣고 4000 g, 4 $^{\circ}C$에서 5분간 원심분리하여 2-3회 세포 내 단백질과 아미노산 분석에 이용하였다. HPLC는 OPA 시약을 만들어 4 $^{\circ}C$에서 24시간 안정화시켜 사용하였고, 용액 A와 B를 미리 준비하여 기울기용리로 30 $^{\circ}C$에서 1ml/min, Ex 330/ Em 420 nm에서 80분간 분석하였다.

• 한국전자파학회논문지
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• 제12권5호
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• pp.755-764
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• 2001

본 논문에서는 M-ary 직교 변조를 사용하는 직접 확산 코드 분할 다중 접속 (DS/CDMA: Direct Sequence/Code Division Multiple Access) 시스템을 위한 최대 근사 (Maximum Lkelihood : ML) 결정 궤환 채널 추정(Decision Feedback Channel Estimation : DFCE) 시스템을 제안한다. 제안된 시스템은 결정 궤환 정보로서 RAKE 수신기의 최대 결합 출력을 사용한다. 제안된 시스템으로부터 추정된 채널 값을 이용하면 파일럿의 삽입없이 RAKE 수신기에서 동기 검파 (coherent demodulation)를 할 수 있고, 동시에 최대 비 결합(Maximum Ration Combining : MRC) 기법을 사용할 수 있다. 그러나 제안된 DFCE 다중 사용자 환경에서 다중 사용자 간섭 (Multiple Access Interference: MAI)으로 인해 심각한 성능의 저하가 발생한다. 이런 문제를 해결하기 위해 다단 병렬 간섭 제거기(Multistage Parallel Interference Cancellation : PIC)를 제안된 시스템과 결합해 본다. 제안된 DFCE에서 추정된 정확한 채널 값은 동기식 검파뿐 아니라 PIC에서 다중 사용자 간섭 신호의 재 생성(regeneration)을 위해서도 쓰인다. 이럴 경우 PIC와 EFCF간에 서로 도움을 주는 이중 효과를 얻게 된다. 실험결과에 의하면 제안된 시스템은 기존의 비동기 검파(noncoherent demodulation) 방식에 비해 다단 PIC를 쓰지 않는 동기 검파의 경우 IE-02의 E$_{b}$/N$_{0}$에서 수용 가능한 사용자 수가 5명에서 약 10으로 2배 증가함을 확인할 수 있었으며, 다단 PIC를 사용한 동기 검파의 경우 약 30명으로 6배 정도가 증가함을 확인할 수 있었다.

• Journal of Microbiology and Biotechnology
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• 제28권7호
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• pp.1078-1085
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• 2018

A salt-tolerant cellulase secreted by a marine Bacillus sp. SR22 strain with wide resistance to temperature and pH was purified and characterized. Its approximate mass was 37 kDa. The endoglucanase, named as Bc22Cel, was purified by ammonium sulfate precipitation, gel filtration chromatography, and extraction from the gel after non-reducing sodium dodecyl sufate-polyacrylamide gel electrophoresis. The optimal pH value and temperature of Bc22Cel were 6.5 and $60^{\circ}C$, respectively. The purified Bc22Cel showed a considerable halophilic property, being able to maintain more than 70% of residual activity even when pre-incubated with 1.5 M NaCl for 1 h. Kinetic analysis of the purified enzyme showed the $K_m$ and $V_{max}$ to be 0.704 mg/ml and $29.85{\mu}mol{\cdot}ml^{-1}{\cdot}min^{-1}$, respectively. Taken together, the present data indicate Bc22Cel as a potential and useful candidate for industrial applications, such as the bioconversion of sugarcane bagasse to its derivatives.

• 대한수의학회지
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• 제29권4호
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• pp.493-501
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• 1989

A total of 108 strains of C jejuni isolated from pigs and chickens were examined for the susceptibility to 10 antimicrobial agents and normal sera of cattle, sheep, guinea pigs and chickens. Minimal inhibitory concentration(MIC) ranges of antimicrobial agents to C jejuni isolates were $${\leq_-}1.56$$ to $${\geq_-}100{\mu}g/ml$$ for erythromycin, rifampin, streptomycin and tetracycline, 50 to $${\geq_-}100{\mu}g$$ for cephalothin, $${\leq_-}1.56$$ to $50{\mu}g$ for ampicillin, $${\leq_-}1.56$$ to $25{\mu}g$ for kanamycin and nalidixic acid, $${\leq_-}1.56$$ to $12.5{\mu}g$ for chloramphenicol and gentamicin. Resistance rates of C jejuni were showed to in order of rifampin(84.7%), tetracycline(56.2 %), erythromycin(17.1%) and ampicillin(3.8%), all of the strains were sensitive to chloramphenicol, gentamicin and kanamycin, and the incidence rates of resistant C jejuni were highly frequent in pig isolates than chicken isolates. The drug resistance patterns of 87 chicken isolates C jejuni to 9 antimicrobial drugs were showed 12 patterns, and Sm Ra Tc(24.1%), Sm Ra(21.8%) and Ra Tc(14.9%) were relatively common, and also 21 pig isolates were showed 6 patterns and Em Sm Ra Tc(57.1%) were most frequent. The majority of the isolates showed multiple drug resistance. Bactericidal activity of 10% normal sera from healthy animals were examined for 60min at $37^{\circ}C$. C jejuni were decreased from 0.4 to 1.0 ${\log}_{10}$(p<0.01), and serum susceptibility were high in order of guinea pig, sheep, chicken and cattle sera. Serum sensitivity of C jejuni Ch-39 strain in increased serum concentation up to 10, 20, 40 and 80% were highly significant. In the normal animal serum, the number of Ch-39 strain were decreased from $1.8{\times}10^4/ml$ to $2.7{\times}10^3/ml$ after 60 min incubation(p<0.01), but the numbers were decreased to $6.6{\times}10^3/ml$ in the heat inactivated normal serum for 30 min at $56^{\circ}C$. Bactericidal activity was restored in the heat inactivated normal serum after the serum of complement source was added.

• 대한의생명과학회지
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• 제10권3호
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• pp.285-291
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• 2004

To determine the magnetic resonance (MR) imaging findings and natural history of cerebral fat embolism in a cat model, and to correlate the MR imaging and histologic fmdings. Intemel carotid artery of 11 cats was injected with 0.1 ml of triolein. T2-weighted, T1-weighted and Gd-enhanced T1-weighted images were obtained serially for 2 hours, 1 days, 4 days, 1 week, 2 weeks and 3 weeks after embolization. Any abnormal signal intensity was evaluated. After MR imaging at 3 weeks, brain tissue was obtained for light microscopic (LM) examination using hematoxylin-eosin (HE) and Luxol fast blue staining, and for electron microscopic examination. The LM examination with HE staining revealed normal histological findings in the greater part of an embolized lesion. Cystic change was observed in the gray matter of 8 cats, while in the gray and white matter of 3 cats. At LM examination, Luxol fast blue, staining demonstrated demyelination around the cystic change occurring in the white matter, and EM examination of the embolized cortex revealed sporadic intracapillary fat vacuoles (n=11) and disruption of the blood-brain barrier (n=4). Most lesions were normal, however, and perivascular interstitial edema and cellular swelling were mild compared with the control side. The greater part of an embolized lesion showed reversible findings at MR and histological examination. Irreversible focal necrosis was, however, observed in gray and white matter at weeks 3.