• Journal of Life Science
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• v.32 no.4
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• pp.303-309
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• 2022

Dystaenia takesimana is an endemic plant found only in Korea, especially on Ulleung Island. The leaves and roots of D. takesimana have been used as food, forage, and oriental medicine. Anti-bacterial, anti-inflammation, antioxidant, and α-glucosidase inhibition biological activities have been reported in the plant's root extract. However, studies concerning the anti-thrombosis activities of D. takesimana are still in the rudimentary stage. In this study, the extracts of the leaf (DT-L), stem (DT-S), and root (DT-R) of D. takesimana were prepared using 70% ethanol, and their anti-thrombosis activities were evaluated. DT-L extracts (0.25 mg/ml) showed strong inhibitions against platelet aggregation, comparable to aspirin, with strong radical scavenging activities. Furthermore, the DT-L extract did not show any RBC hemolysis up to 1 m/ml. The ant-coagulation and antioxidant activities of the DT-S extract were ignorable. While the DT-R extract showed inhibitions against thrombin and blood coagulation factors, it also showed strong platelet aggregation. This is a first report of the anti-thrombosis activities of D. takesimana, and our results suggest that DT-L could be developed as a valuable bioresource for high value-added products.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.9C
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• pp.669-675
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• 2008

For an odd prime p, n=4k and $d=((p^2k+1)/2)^2$, there are $(p^{2k}+1)/2$ distinct decimated sequences, s(dt+1), $0{\leq}l<(p^{2k}+1)/2$, of a p-ary m-sequence, s(t) of period $p^n-1$. In this paper, it is shown that the cross-correlation function between s(t) and s(dt+l) takes the values in $\{-1,-1{\pm}\sqrt{p^n},-1+2\sqrt{p^n}\}$ and their, cross-correlation distribution is also derived.

• Journal of Biomedical Engineering Research
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• v.43 no.5
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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.

• Journal of the Korean Applied Science and Technology
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• v.36 no.1
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• pp.47-58
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• 2019

This study aimed to investigate the improvement effect of turmeric (Curcuma longa L.) on the lipid component, protein and electrolyte concentration in dyslipidemic rats. Sprague-Dawley rats (24 male) were divided into four groups, namely the ND (normal-nondyslipidemic diet), NT (normal-nondyslipidemic diet+5% turmeric), DD (control-dyslipidemic diet), and DT groups (dyslipidemic diet+5% turmeric). Rats were sacrificed at the end of 5 weeks after experiment diet. In this study, turmeric diet (NT, DT) groups in lipid composition as evidenced from the significantly reduction of serum total cholesterol, low density lipoprotein-cholesterol (LDL-cholesterol), atherosclerotic index (AI), cardiac risk factor (CRF), triglyceride (TG), phospholipid (PL), free cholesterol, cholesteryl ester, blood glucose and non esterified fatty acid (NEFA), and elevation of high density lipoprotein-cholesterol (HDL-cholesterol) (p<0.05). The serum globulin concentration was significantly decreased (p<0.05), and the albumin concentrations were increased in turmeric diet than dyslipidemic rats. Concentrations of sodium (Na) and chlorine (Cl) in sera were lower in the DT group than DD group. Concentrations of total calcium (T-Ca), phosphorus (Pi) and potassium (K) in sera were higher in the ND, NT and DT groups than DD group. Therefore, it was concluded that the 5% turmeric diet used in the condition of this study had a beneficial effect on dyslipidemia.

• Proceedings of the KIPE Conference
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• 2014.07a
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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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• v.22 no.2
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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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• v.23 no.2
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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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• v.29 no.12
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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.

• Korean Journal of Agricultural Science
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• v.32 no.2
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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.

• Journal of the Korea institute for structural maintenance and inspection
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• v.18 no.5
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• pp.59-67
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• 2014

In tension lap splices of straight deformed bars, KCI Code (KCI2012) and ACI Code (ACI318-11) requires that the lap lengths for class B splice are 1.3 times as development length. KCI2012 contains development length provisions for the use of headed deformed bars in tension and does not allow their tension lap splices. The purpose of this experimental study is to evaluate that KCI2012 equation for the development length, $l_{dt}$, of headed bars can be used to calculate the lap length, $l_s$, of headed deformed bars in grade SD400 and SD500, having specified yield strength of 400 and 500 MPa. Test results showed that specimens with $l_s$ equal to $1.3l_{dt}$ had maximum flexural strengths as 1.16~1.31 times as the nominal flexural strengths, flexural failure mode, and ductility. These observations indicate that $1.3l_{dt}$ is suitable to the tensile lap length of headed deformed bars in grade SD400 and SD500.