• 생명과학회지
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• 제32권4호
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• pp.303-309
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• 2022

섬바디(Dystaenia takesimana)는 대한민국 울릉도 등지에만 분포하는 우리나라 특산 식물의 하나로, 잎은 식용 및 사료로, 뿌리는 약용으로 이용되고 있다. 현재까지 섬바디 뿌리의 항균, 항염증, 항산화 및 α-glucosidase 저해활성이 보고된 바 있으나, 섬바디의 항혈전 활성에 대한 연구는 이루어진 바 없다. 본 연구에서는 울릉도산 섬바디의 잎(DT-L), 줄기(DT-S) 및 뿌리(DT-R)를 구분하여 각각 70% 에탄올 추출물을 조제하고 이들의 혈액응고 저해, 혈소판 응집저해, 항산화 활성 및 적혈구 용혈활성을 평가하였다. 그 결과, DT-L 추출물은 2.5 mg/ml 농도까지 혈액응고에는 영향을 미치지 않았으나 0.25 mg/ml 농도에서 aspirin과 비교할 만한 강력한 혈소판 응집저해활성을 보였으며, 우수한 활성 라디컬 소거능(DPPH anion, ABTS cation 및 nitrite)과 환원력을 나타내었다. 또한 DT-L 추출물은 적혈구 용혈활성도 나타나지 않아 신규의 항혈전제 소재로 개발 가능함을 확인하였다. 반면, DT-S 추출물은 혈액응고 저해, 혈소판 응집저해 및 항산화 활성이 미약하였으며, DT-R 추출물은 트롬빈 저해 및 혈액응고인자 저해에 의한 혈액응고 저해활성이 우수한 반면 혈소판 응집 촉진활성도 강력하였으며 적혈구 용혈활성도 강력하여 항혈전 용도로 이용은 제한되었다. 본 연구는 섬바디의 항혈전 활성에 대한 최초 보고이며, 전 세계적으로 희귀한 섬바디를 이용한 고부가가치 생물소재 개발이 가능함을 제시하고 있다.

• 한국통신학회논문지
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• 제33권9C호
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• pp.669-675
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• 2008

홀수인 소수 p와 n=4k, 그리고 $d=((p^2k+1)/2)^2$에 대해서, 주기가 $p^n-1$인 p-진 m-수열 s(t)에 대해서 $(p^{2k}+1)/2$개의 서로 다른 decimated 수열들 s(dt+1), $0{\leq}l<(p^{2k}+1)/2$가 존재한다. 이 논문에서는 s(t)와 s(dt+l), $0{\leq}l<(p^{2k}+1)/2$ 사이의 상호상관 값이 $\{-1,-1{\pm}\sqrt{p^n},-1+2\sqrt{p^n}\}$과 같음을 보이고, 상호 상관 값의 분포를 유도하였다.

• 대한의용생체공학회:의공학회지
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• 제43권5호
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• pp.331-340
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• 2022

Early afterdepolarization (EAD), a significant cause of fatal ventricular arrhythmias including Torsade de Pointes (TdP) in long QT syndromes, is a depolarizing afterpotential at the plateau or repolarization phase in action potential (AP) profile early before completing one pace. AP duration prolongation is related to EAD but is not necessarily accounted for EAD. Several computational studies suggested EAD can form from an abnormality in the late plateau and/or repolarization phase of AP shape. In this sense, we hypothesized the slope during repolarization has the characteristics to predict TdP risk, mainly focusing on the maximum slope during repolarization (dVm/dt_{max_repol}). This study aimed to predict the sensitivity of dVm/dt_{max_repol} to ion channel conductances as a TdP risk metric through a population simulation considering multiple effects of simultaneous reduction in six ion channel conductances of g_NaL, g_Kr, g_Ks, g_to, g_K1, and g_CaL. Additionally, we verified the availability of dVm/dt_{max_repol} for TdP risk prediction through the correlation analysis with qNet, the representative TdP metric. We performed the population simulations based on the methodology of Gemmel et al. using the human ventricular myocyte model of Dutta et al. Among the sixion channel conductances, dVm/dt_{max_repol} and qNet responded most sensitively to the change in g_Kr, followed by g_NaL. Furthermore, dVm/dt_{max_repol} showed a statistically significant high negative correlation with qNet. The dVm/dt_{max_repol} values were significantly different according to three TdP risk levels of high, intermediate, and low by qNet (p<0.001). In conclusion, we suggested dVm/dt_{max_repol} as a new biomarker metric for TdP risk assessment.

• 한국응용과학기술학회지
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• 제36권1호
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• pp.47-58
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• 2019

울금(Curcuma longa L.)이 이상지질혈증 유발 흰쥐의 지질성분과 단백질 및 전해질 농도에 미치는 영향을 확인하기 위하여 기본 식이를 섭취시킨 ND군, 정상 실험군에 5% 울금 급여군(NT군), 이상지질혈증 유발 실험군(DD군)과 DD군에 5% 울금을 섭취시킨 실험군(DT군)으로 나누어 실험을 행하였다. 혈청 지질성분(총 콜레스테롤, LDL-콜레스테롤, 중성지질, 인지질, 유리 콜레스테롤, 콜레스테롤 에스테르), 혈당 및 유리지방산(non esterified fatty acid, NEFA)의 농도와 동맥경화지수(atherosclerotic index, AI), 심혈관 위험지수(cardiac risk factor, CRF)는 이상지질혈증군에서 여타 실험군과 비교하였을 때 유의적인 증가를 나타내었으며(p<0.05), 5% 울금 급여군에서 감소시키는 것으로 나타났다. DD군에 비해 DT군에서 고밀도 지단백 콜레스테롤(high density lipoprotein-cholesterol, HDL-콜레스테롤) 및 총 콜레스테롤에 대한 HDL-콜레스테롤 농도 비는 유의적인 증가를 보였다(p<0.05). 혈청 단백질의 농도에 있어서, DT군은 DD군에 비하여 흰쥐의 혈청 알부민(albumin) 농도와 알부민/글로불린 비(albumin/globulin ratio, A/G 비)의 증가 및 글로불린(globulin) 농도는 감소되는 것으로 관찰되었다. 나트륨(Na) 및 염소(Cl)는 DT군에서 DD군 보다 농도가 감소된 것으로 확인하였다. 이상의 결과, 5% 울금은 흰쥐의 혈청 지질성분 개선과 단백질 및 전해질 농도 조절에 도움이 되는 것으로 사료된다.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2014년도 전력전자학술대회 논문집
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• pp.333-334
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• 2014

Converters employing IGCTs usually require di/dt snubber and Over Voltage Protection (OVP) circuit for the protection of IGCTs and fast diodes. In these IGCT-based converters, conventional di/dt snubber and OVP circuit dissipates a significant amount of power loss. To reduce this loss of conventional di/dt snubber and OVP circuit, this paper proposes a flyback type snubber circuit with di/dt limiting characteristic for IGCT-based converters in medium voltage wind turbines. This flyback type snubber circuit simply consists of a flyback type transformer and diode. The proposed circuit reduces loss and simplifies conventional di/dt snubber by adopting the flyback type transformer. Loss analysis of conventional di/dt snubber and OVP circuit is performed for the 3-level NPC type back-to-back VSC supplied from grid voltage of 6.9kV. The proposed flyback type snubber circuit can save the loss of conventional snubber circuit in the 3L-NPC type back-to-back VSC in multi-MW MV wind turbine. The proposed snubber circuit has a fewer number of components and improved efficiency leading to a reliable and efficient wind turbine systems.

• The Korean Journal of Pain
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• 제22권2호
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• pp.151-157
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• 2009

Background: We hypothesized that if a fluoroscopic image of the lumbar sympathetic ganglion block (LSGB) showed the spread patterns of contrast at both the L2/3 and L4/5 disc areas, then this would demonstrate a more profound blockade effect because the spread patterns are close to sympathetic ganglia. In addition, we compared the effects of LSGB and transforaminal epidural steroid injection (TFESI) for the patients suffering with spinal stenosis. Methods: Eighty patients were divided into two groups (Group S: the patients treated with TFESI, Group L: the patients treated with LSGB). The patients of group L were classified into three groups (groups A, B and, C) according to their contrast spread pattern. The preblock and postblock temperature difference between the ipsilateral and contralateral great toe ($DT^{pre}$, $DT^{post}$, $^{\circ}C$), and the DTnet were calculated as follows. $DT^{net}$ = $DT^{post}$ - $DT^{pre}$. Results: Both group showed a significant reduction of the visual analogue score (VAS) and the Oswestry disability index (ODI) score. Only the patients of group L showed a significant increase of their walking distance (WD). Group A showed the most significant changes in the $DT^{post}$ ($6.1{\pm}1.2^{\circ}C$, P = 0.021), and the DTnet ($6.0{\pm}1.0^{\circ}C$, p = 0.023), as compared to group C. Conclusions: LSGB showed a similar effect on the VAS, and ODI, and a significant effect, on WD, compared with TFESI. Group A showed a significant sympatholytic effect, as compared to group C.

• The Korean Journal of Pain
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• 제23권2호
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• pp.131-136
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• 2010

Background: We prospectively evaluated the incidence and possible factors causing intramuscular injection during lumbar sympathetic ganglion block and compared the multiple needle technique to the single technique to obtain a profound and complete block effect. Methods: Among 83 patients, 58 patients (group A, n = 27, multiple needle technique and group B, n = 31, single needle technique) were reevaluated for the changes of skin temperature (Ts) and mean segment of longitudinal contrast spread. After injecting the contrast agent, the incidence of psoas muscle injection and the change of Ts was compared between two groups. Results: The incidence of psoas muscle injection was 21.3% (46/216) and it was associated with the level of injection (L2) significantly (${\chi}_2$ = 14.773, P = 0.001). $DT^{post}$ (postblock temperature difference between ipsilateral and contralateral great toe, $4.6{\pm}2.8^{\circ}C$, $1.8{\pm}1.6^{\circ}C$, P < 0.001 for group A and B) and $DT^{net}$ ($DT^{post}$ - $DT^{pre}$, $3.9{\pm}2.7^{\circ}C$, $1.5{\pm}1.5^{\circ}C$, P < 0.001 for group A and B) was significantly higher in group A. The mean segment of longitudinal contrast spread was $8.1{\pm}0.9$ for group A and $3.2{\pm}1.6$ for group B (P < 0.001). Conclusions: The LSGB at the L2 level showed the lowest incidence of psoas muscle injection of contrast. Multiple needle approach showed more significant increase of $DT^{net}$ and $DT^{post}$.

• Journal of Microbiology and Biotechnology
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• 제29권12호
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• pp.1882-1893
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• 2019

β-Glucosidases and β-xylosidases are two categories of enzymes that could cleave out non-reducing, terminal β-D-glucosyl and β-D-xylosyl residues with release of D-glucose and D-xylose, respectively. In this paper, two functional β-glucosidase Dth3 and β-xylosidase Xln-DT from Dictyoglomus thermophilum were heterologously expressed in E.coli BL21 (DE3). Dth3 and Xln-DT were relatively stable at 75℃ and were tolerant or even stimulated by glucose and xylose. Dth3 was highly tolerant to glucose with a K_i value of approximately 3 M. Meanwhile, it was not affected by xylose in high concentration. The activity of Xln-DT was stimulated 2.13-fold by 1 M glucose and 1.29-fold by 0.3 M xylose, respectively. Furthermore, the βglucosidase Dth3 and β-xylosidase Xln-DT showed excellent selectivity to cleave the outer C-6 and C-3 sugar moieties of ASI, which established an effective and green method to produce the more pharmacologically active CAG, an exclusive telomerase activator. We measured temperature, pH and dosage of enzyme using a single-factor experiment in ASI biotransformation. After optimization, the optimal reaction conditions were as follows: 75℃, pH 5.5, 1 U of Dth3 and 0.2 U of Xln-DT, respectively. Under the optimized conditions, 1 g/l ASI was transformed into 0.63 g/l CAG with a corresponding molar conversion of 94.5% within 3 h. This is the first report to use the purified thermostable and sugar-tolerant enzymes from Dictyoglomus thermophilum to hydrolyze ASI synergistically, which provides a specific, environment-friendly and cost-effective way to produce CAG.

• 농업과학연구
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• 제32권2호
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• pp.223-231
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• 2005

In order to know the residual pattern of pesticides and predict to the degradation period until below MRL, we experimented diazinon, iprodinon and chlorfenapyr for shallot. They were the most detected pesticide in shallot by NAQS (National Agricultural product Quality management Service) survey. In this experiment, we sprayed those pesticides 15days before harvest and analyzed 0, 1, 2, 3, 5, 7, 10, 14 day sample to establish logical equation and to calculate $DT_{50}$. During the cultivating period, the residue amount of diazinon was changed from 1.02 mg/kg (0 day) to 0.01 mg/kg (14 day), $DT_{50}$ was 2.19 days, and iprodione was changed from 1.45 mg/kg (0 day) to 0.14 mg/kg (14 day), $DT_{50}$ was 4.15 days, and chlorfenapyr was changed from 1.5 mg/kg (0 day) to 0.01 mg/kg (14 day), $DT_{50}$ was 1.97 days. The $DT_{50}$ of double amount in those pesticides, diazinon was 2.24 days, iprodione was 4.82 days, and chlorfenapyr was 2.24 days, respectively.

• 한국구조물진단유지관리공학회 논문집
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• 제18권5호
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• pp.59-67
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• 2014

현행 콘크리트구조기준 (KCI2012) 및 ACI318-11에서 B급이음된 일자형 이형철근에 대하여 인장력에 대한 겹침이음길이를 정착길이의 1.3배로 산정하고 있다. 동일 기준에서 확대머리 이형철근의 정착길이를 제시하고 있지만 겹침이음상세에 대한 규정은 없다. 이에 본 연구에서는 400MPa과 500MPa 설계기준항복강도를 가지는 확대머리 이형철근의 겹침이음실험을 실시함으로써, 기준의 정착길이식을 겹침이음설계에 적용가능한 지를 평가하고자 하였다. 실험결과, SD400과 SD500의 설계기준항복강도를 적용한 확대머리 이형철근에 대하여 겹침이음길이를 정착길이의 1.3배로 산정할 경우, 실험 최대휨강도가 공칭휨강도에 비하여 16~31% 크게 평가되었고 연성적인 휨파괴 거동을 나타내었다. 따라서, 이들 철근에 대해 정착길이 1.3배의 겹침이음길이로 설계함으로써 강도 및 변형성능 측면에서 겹침이음 성능을 확보할 수 있는 것으로 사료된다.