• 대한전자공학회논문지
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• 제22권5호
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• pp.69-74
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• 1985

본 논문에서는 먼저 Sensitivity가 가장 낮은 LC Ladder 필터로 부터 FDNR frequency dependent negative resists.) 방식을 이용하여 5차 Butterworth 저역 통과 능동 RC필터를 설계하였으며 능동 RC 필터를 SCF(switched capacito, filter)로 변조하는 과정에서 Bilinear Z변환을 이용하였다. Bilinear Z 변환으로 설계된 SCF에서 aliasing 현상은 피할수 있으나 주파수 대곡이 발생한다. 아나로그 필터를 디지틀 릴터로 변환하면 이러한 영향으로 속단 주파수 영역이 일치하지 않으므로 이것을 적게 하기 위하여 Prewarping을 해준다. 그 결과 Prewarping된 SCF는 Bilinear Z 변환된 SCF보다 각파수 이유이 현저하게 개선됨을 확인하였다.

• 대한의용생체공학회:의공학회지
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• 제20권3호
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• pp.291-297
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• 1999

다채널의 심전도 신호에서, 소수의 리이드에 만 잡음이 유기되고 나머지 대부분의 리이드 신호들은 이 잡음과 통계적인 상관 관계가 없을 때, source consistency filtering(SCF) 은 이러한 잡음의 감쇄에 매우 효과적이다. 특히, SCF는 원래 신호의 왜곡을 최소화하면서 , 선택적으로 잡음 만을 제거하는 매우 우수한 특성을 가진다. 이러한 특성은 하나의 신호원에서 기인하는 다채널 신호들의 공간적 및 시간적 상관관계를 모두 이용함으로서 가능하다. 본 논문에서는 SCF의 원리 및 구현 방법을 구체적으로 기술하여 이 방법에 대한 이해를 증진하고자 한다. 또한 기존의 방법을 개선한 새로운 SCF를 제안하였으며 , 이의 효과적인 구현에 필요한 알고리즘의 상세한 설계 지침을 제시하였다. 다채널의 심전도 신호를 대상으로 하여 그 성능을 검증하였고, 현재의 SCF 가 가지는 한계를 명확히 하며, 개선의 방향을 제시하였다.

• 한국응용약물학회:학술대회논문집
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• 한국응용약물학회 2003년도 Annual Meeting of KSAP : International Symposium on Pharmaceutical and Biomedical Sciences on Obesity
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• pp.76-76
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• 2003

Mast cells accumulation can be causally related with several allergic inflammations. Previous work has demonstrated that glucocorticoids decreased tissue mast cell number and stem cell factor (SCF)-induced migration of mast cells required p38 mitogen-activated protein kinase (MAPK) activation. In the present study, we investigated the effects of dexamethasone on SCF-induced migration of rat peritoneal mast cells (RPMCs). SCF significantly induced migration of RPMCs at 4 h. Dexamethasone dose-dependently inhibited SCF-induced migration of RPMCs (about 90.1% at 100 nM, P<0.05). MAPK p38 inhibitor, SB203580 (20 ${\mu}$M) also inhibited the SCF-induced migration. The ability of SCF to enhance morphological alteration and F -actin formation was also abolished by treatment of dexamethasone. Dexamethasone inhibited SCF-induced p38 MAPK activation to near basal level and induced the MKP-1 expression. In addition, SCF-induced inflammatory cytokine production was significantly inhibited by treatment of dexamethasone or SB203580 (p<0.01). Our results show that dexamethasone potently regulates SCF -induced migration, p38 MAPK activation and inflammatory cytokine production through expression of MKP-l protein in RPMCs. Such modulation may have functional consequences during dexamethasone treatment, especially mast cell-mediated allergic inflammation disorders.

• 한국수정란이식학회지
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• 제26권3호
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• pp.171-180
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• 2011

In this study I report that in vitro development rates of bovine nuclear transfer embryos activated either with boar sperm cytosolic factor (SCF) or with ionomycin followed by cycloheximide (CHX) and subsequent in vivo developmental rates after embryo transfer are related to blastocyst quality as evaluated by apoptosis analysis. SCF was extracted from porcine semen then purified for post-activation injection after nuclear transfer. The optimal timing for SCF injection was determined to be at least 22 h post-IVM for parthenogenetic activation of bovine oocyies. A total of 364 oocytes were successfully enucleated and 268 (73.6%) fused and were injected with SCF. The survival rate of fused and injected embryos was 109/113 (96.5%) after 2 h. The cleavage rates of nuclear transfer embryos after 3 d of culture in the ionomycin/CHX treated group were significantly higher than those of the SCF-activated group (93.3% vs 81.7%, p<0.01, respectively). However, at 7 d and 9 d there was no significant difference between the total developmental rates to blastocyst for either treatment group. Total blastocyst cell numbers were also not significantly different between the two activation treatments (ionomycin/CHX: 149.5${\pm}$7.7 vs. SCF: 139.3${\pm}$4.4 cells). In contrast, the apoptotic levels in the SCF blastocysts were higher than those produced after the chemical treatment (28.2${\pm}$5.1% vs. 8.8${\pm}$0.6%, respectively). A total of 18 expanded or hatching blastocysts was transferred to nine synchronized recipients in each activation group; 5/9 (55.5%) and 2/9 (22.2%) were pregnant at 40 d in the ionomycin/CHX treatment and SCF activated group, respectively. However, only one went to term in the ionomycin/CHX treatment while none of the pregnancies from the SCF group were maintained by 90 d. In conclusion, these results suggest that SCF derived from different species is a limited activator to be used for activation after bovine nuclear transfer in lieu of a chemical activation protocol.

• Reproductive and Developmental Biology
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• 제35권3호
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• pp.319-327
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• 2011

This study investigated whether the addition of porcine sperm cytosolic factor (SCF) at fusion/activation affects in vitro development of porcine parthenogenetic(PA) and nuclear transfer (NT) embryos. To determine the optimum concentration of SCF, control group of oocytes was activated with 0.3M mannitol (1.0 mM $CaCl_2{\cdot}2H_2O$), other three groups of oocytes were parthenogentically activated with the fusion medium (0.1mM $CaCl_2{\cdot}2H_2O$) supplemented with 100, 200 or 300 ${\mu}$g/ml SCF, respectively. Matured oocytes were activated with two electric pulses (DC) of 1.2 kv/cm for 30 ${\mu}$sec. The activated embryos were cultured in PZM-3 under 5% $CO_2$ in air at $38.5^{\circ}C$ for 6 days. Oocytes activated in the presence of SCF showed a significantly higher blastocyst rate than control (p<0.05). Apoptosis rate was significantly lower in 100 ${\mu}$g/ml SCF group than other groups (p<0.05). Cdc2 kinase activity in control and SCF treatment group of oocytes was determined using MESACUP cdc2 kinase assay kit at 1, 5, 10, 15, 30, 45 and 60 min after activation. Cdc2 kinase activity was significantly decreased (p<0.05) in SCF group than MII oocytes or control within 5 min. For NT embryo production, reconstructed oocytes were fused in the fusion medium supplemented with 0.1 mM $CaCl_2{\cdot}2H_2O$ (T1), 1.0 mM $CaCl_2{\cdot}2H_2O$ (T2) and 0.1 mM $CaCl_2{\cdot}2H_2O$ with 100 ${\mu}$g/ml SCF (T3). Fused embryos were cultured in PZM-3 under 5% $CO_2$ in air at $38.5^{\circ}C$ for 6 days. Developmental rate to blastocyst stage was significantly higher in T3 than other groups (23.0% vs. 13.5 to 15.2%) (p<0.05). Apoptosis rate was significantly lower in T3 than T1 or T2 (p<0.05). The relative abundance of Bax-${\alpha}$/Bcl-xl was significantly lower in in vivo or SCF group than that of control (p<0.05). Moreover, the expression of p53 and caspase3 mRNA was significantly lower in in vivo or SCF group than that of control (p<0.05). These results indicate that the addition of SCF at fusion/activation might improve in vitro development of porcine NT embryos through regulating cdc2 kinase level and expression of apoptosis related genes.

• 생명과학회지
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• 제21권12호
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• pp.1726-1731
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• 2011

본 연구의 목적은 누에형질전환체를 이용하여 재조합단백질 대량생산 시스템을 개발하는 것으로서, 본 실험에서는 hSCF유전자를 이용하여 누에에서 재조합단백질을 생산하였다. 실험에 사용된 piggyBac 전이벡터는 hSCF 유전자의 발현 조절을 위해 초파리 유래의 dHsp70 promoter를 사용하였고, EGFP marker유전자는 3xP3 promoter로 발현을 조절하였다. 총 1,020 개의 누에알에 microinjection 하여 G1 세대에서 22 bloods의 형질전환체를 선발하였고, 선발된 누에형질전환체는 초기배 단계의 눈과 신경조직, 유충과 번데기 그리고 성충의 눈에서 GFP 형광을 관찰 할 수 있었다. hSCF 재조합단백질의 발현은 Western blot 분석으로 확인 할 수 있었고, inverse PCR 분석을 통해서 누에 게놈에 전이벡터가 삽입된 것을 확인할 수 있었다. 지금까지의 실험 결과에서 hSCF 재조합 단백질이 누에에서 생산될 수 있음을 확인 할 수 있었다. 비록 누에에서 생산된 hSCF 재조합단백질의 생리활성에 대한 실험이 추후에 요구되지만, 이러한 실험결과는 piggyBac 전이벡터와 microinjection 법으로 누에에서 고부가가치의 재조합단백질을 대량생산 할 수 있음을 보여 주었다고 할 수 있겠다. 따라서 누에를 유용물질 생산을 위한 생체반응기로서 활용할 수 있을 것으로 기대된다.

• 동의생리병리학회지
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• 제26권3호
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• pp.330-337
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• 2012

This study was performed to assess the Effect of SCF(Schisandrae Chinensis Fructus) on Keratinocyte Damage by UV irradiation. The effect of SCF were determined in UV irradiated HaCaT. We measured LDH release and NO release from HaCaT to elucidate the effect of SCF. And iNOS, TNF-${\alpha}$, COX-2, Bax, Bcl-2, Bcl-xL, c-jun, c-fos gene expression were determined in HaCat using real time PCR method. The results are as follows. SCF inhibited LDH-release, NO production in UV irradiated HaCaT. SCF increased the gene expression Bax, Bcl-2 and Bcl-xL protein in UV irradiated HaCaT. SCF suppressed the gene expression TNF-${\alpha}$ in UV irradiated HaCaT. SCF suppressed the gene expression iNOS, c-fos, and c-jun in UV irradiated HaCaT. SCF not affected the suppression of the gene expression COX-2 in UV irradiated HaCaT. The study showed SCF inhibited the cell damage in UV irradiated HaCaT.

• 대한원격탐사학회지
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• 제34권4호
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• pp.625-638
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• 2018

In this paper, we derive i) a function to estimate snow cover fraction (SCF) from a MODIS satellite image that has a wide observational area and short re-visit period and ii) a function to determine snow depth from the estimated SCF map. The SCF equation is important for estimating the snow depth from optical images. The proposed SCF equation is defined using the Gaussian function. We found that the Gaussian function was a better model than the linear equation for explaining the relationship between the normalized difference snow index (NDSI) and the normalized difference vegetation index (NDVI), and SCF. An accuracy test was performed using 38 MODIS images, and the achieved root mean square error (RMSE) was improved by approximately 7.7 % compared to that of the linear equation. After the SCF maps were created using the SCF equation from the MODIS images, a relation function between in-situ snow depth and MODIS-derived SCF was defined. The RMSE of the MODIS-derived snow depth was approximately 3.55 cm when compared to the in-situ data. This is a somewhat large error range in the Republic of Korea, which generally has less than 10 cm of snowfall. Therefore, in this study, we corrected the calculated snow depth using the relationship between the measured and calculated values for each single image unit. The corrected snow depth was finally recorded and had an RMSE of approximately 2.98 cm, which was an improvement. In future, the accuracy of the algorithm can be improved by considering more varied variables at the same time.

• 폴리머
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• 제33권6호
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• pp.530-536
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• 2009

고리지방족 에폭시와 산무수물 경화제계에 탄소단섬유(SCF)와 유리단섬유(SGF)를 첨가하여 복합재를 제조한 다음 이들의 열적/기계적 특성을 조사하였다. 열기계분석법으로 측정된 열팽창계수(CTE)의 감소 효과를 보면 낮은 단섬유 함량에서는 두 섬유가 거의 비슷하나, 함량이 증가하면 SCF가 SGF에 비해 훨씬 효과적이었다. SCF 강화 복합재에 대한 CTE 실험값을 이론식에 적용해 본 결과 함량이 낮을 때는 혼합법칙(mixture rule)에 잘 맞으며, 함량이 높아지면 Craft-Christensen 식에 근접하였다. 또한, 유리상($30^{\circ}C$과 고무상($180^{\circ}C$)에서의 저장탄성률은 단섬유를 첨가하였을 때 크게 증가하였다. 전자주사현미경(SEM)으로 파단면을 관찰하여본 결과 이와 같은 결과는 단섬유와 에폭시 매트릭스간의 계면접착력과 밀접한 관계가 있음을 알 수 있었다.

• Journal of Animal Science and Technology
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• 제63권5호
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• pp.1086-1097
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• 2021

This study examined the impact of using total mixed ration (TMR) and concentrate on feed intake, daily gain, carcass yield grade, and carcass quality grade of Hanwoo steers and its subsequent economic efficiency. Thirty six 7-month-old Hanwoo steers were assigned to one of the four treatment groups, and each group was divided into three repeated pens, with each repeated pen comprising three steers. The treatment groups were: 1) separate feeding with commercial concentrate and forage (namely, SCF) for the entire experimental period; 2) TMR feeding for a growing period followed by SCF for the early and late fattening period (namely, TMRGSCF); 3) TMR feeding for growing and an early fattening period followed by SCF for the late fattening period (namely, TMREFSCF); and 4) TMR feeding for the entire experimental period (namely, TMRW). The results showed that the SCF treatment had significantly (p < 0.05) higher feed intake during the growing period than other treatments. In contrast, the total feed intake had little difference during early and late fattening as well as the whole period regardless of feeding strategies. Daily gain showed no difference during the growing period. However, it was significantly higher in SCF and TMREFSCF treatments for the early and late fattening period, respectively (p < 0.05). The daily gain during the total raising period is in the order of TMREFSCF > TMRGSCF > SCF > TMRW. Carcass characteristics, including carcass weight, loin eye muscle area, and carcass yield grade, did not significantly differ among different treatments. However, TMRW treatment, wherein TMR was fed for a long time, showed that the cold carcass weight was less compared with other treatments, but carcass yield grade was higher with thinner backfat. Backfat thickness was in the order of SCF > TMRGSCF > TMREFSCF > TMRW, showing that the thickness reduced with longer TMR feeding (p < 0.05). TMRGSCF, which numerically had a higher carcass quality grade, showed higher economic efficiency, whereas SCF showed low economic efficiency. In conclusion, it was more feasible to apply TMR strategy in the growing and early fattening period and then SCF for the early or late fattening period to improve carcass yield, quality grade, and economic efficiency.