• Journal of Pharmacopuncture
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• v.12 no.4
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• pp.33-50
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• 2009

Objectives : This study was conducted to confirm validation and stability of concentration analysis method of pure melittin (Sweet Bee Venom-Sweet BV) extracted from the bee venom by utilizing protein isolation method of gel filtration. Methods : All experiments were conducted at Biotoxtech, a non-clinical studies authorized institution, under the regulations of Good Laboratory Practice (GLP). Standard solutions of melittin (SIGMA, USA) and test substances were dispensed and were analyzed with HPLC for Sweet BV to secure the validation of analysis. Results : 1. Measurement of system suitability of Sweet BV satisfied criterion of below 3%. 2. Confirming Linearity of Sweet BV in 10-200${\mu}g/m\ell$ solution yielded correlation coefficient (r) of 0.995 and accuracy of 85-115% which satisfy criterion. 3. Measurement of Specificity of Sweet BV didn't yield any substance affecting the peak of test substances, but detected at 21.22min verified as the test substance. 4. Confirming Intra-day of Sweet BV, accuracy and precision of 0.1, 100${\mu}g/m\ell$ were 105.70, 95.81 and 0.66, 0.73, respectively, satisfying both criteria of accuracy (85-115%) and precision (within 10%). 5. To measure Stability in autosampler, all samples used in Intra-day reproducibility sat in the autosampler for five hours and were re-analyzed. Both variability and precision satisfied the criteria. 6. Homogeneity of Sweet BV (0.1, 100${\mu}g/m\ell$) at upper, middle, and lower layers all satisfied the accuracy and precision criteria. 7. Stability of Sweet BV (0.1, 100${\mu}g/m\ell$) at room temperature for four hours and refrigerated for 7 days all satisfied the criterion. 8. For the measurement of Quality control, QC samples measured on the first and eighth day all satisfied accuracy and precision criteria. Conclusion : Above experiment data satisfies validation and stability of concentration analysis method of Sweet BV.

• Transactions of the Korean Society of Automotive Engineers
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• v.24 no.3
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• pp.302-309
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• 2016

Urea-SCR system is currently regarded as promising NOx reduction technology for diesel engines. SCR system has to achieve maximal NOx conversion in combination with minimal $NH_3$ slip. In this study, model based open loop control for urea injection was developed and assessed in the European Transient Cycle (ETC) for heavy duty diesel engine. On the basis of the transient modeling, the kinetic parameters of the $NH_3$ adsorption and desorption are calibrated with the experimental results performed over the zeolite based catalyst. $NH_3$ storage or surface coverage of SCR catalyst can not be measured directly and has to be calculated, which is taken into account as a control parameter in this model. In order to reduce $NH_3$ slip while maintaining NOx reduction, $NH_3$ storage control algorithm was applied to correct the basic urea quantity. If the actual $NH_3$ surface coverage is higher than the maximal $NH_3$ surface coverage, the urea injection quantity is significantly reduced in the ETC cycle. By applying this logic, the resulting $NH_3$ slip peak can be avoided effectively. With optimizing the kinetic parameters based on standard SCR reaction, it suggests that a simplified, less accurate model can be effective to evaluate the capability of model based control in the ETC cycle.

• Analytical Science and Technology
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• v.31 no.3
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• pp.107-111
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• 2018

Currently, ultraviolet-visible spectrophotometry and titration methods are used for assay tests of tramadol hydrochloride injection and raw material in the Korean Pharmacopoeia XI (KP XI). Titration has also been used in the British Pharmacopoeia (BP 2013) for the assay test of tramadol hydrochloride, and the HPLC assay for tramadol hydrochloride raw material has been used in the United States Pharmacopeia (USP 39). In this study, we developed an alternative HPLC assay method for tramadol hydrochloride injection that is up to date and specific, and employs the same method as tramadol hydrochloride capsules. Validation of the HPLC method was conducted to determine linearity, precision, accuracy, system suitability, and robustness. The linearity of the calibration curves in the desired concentration range was good ($r^2$ > 0.9999). RSDs of intra-day precision obtained were 0.05-0.08 % and inter-day precision obtained were 0.08-0.19 %. Accuracy was obtained with recoveries in the range of 98.16 % and 100.90 %. As a result of the system's suitability, the RSD of both retention time and the peak area obtained were 0.07 %. The values of the plate number and tailing factor of tramadol hydrochloride obtained were 7076 and 1.16, respectively. Because of the intermediate precision and robustness of the developed assay, it is expected to become a valuable tool for revising the Korean Pharmacopoeia (KP XI).

• Journal of Biomedical Engineering Research
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• v.28 no.1
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• pp.148-152
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• 2007

In this paper, we have synthesized $Gd_2O_3:Eu^{3+}$ nano phosphor particle using a low temperature solution-combustion method. We have investigated the structure and the luminescent characteristic as the sintering temperature and europium concentration. From XRD(X-ray diffraction) and SEM(scanning electron microscope) results, we have verified that the phosphor particle was fabricated a spherical shape with $30{\sim}40nm$ particle size. From the photoluminescence results, the strong peak exhibits at 611 um and the luminescent intensity depends on europium concentration. $Gd_2O_3:Eu$ fine phosphor particle has shown excellent luminescent efficiency at 5 wt% of europium concentration. The phosphors calcinated at $500^{\circ}C$ have possessed the x-ray peaks corresponding to the cubic phase of $Gd_2O_3$. As calcinations temperature increased to $700^{\circ}C$, the new monoclinic phase has identified except cubic patterns. From the luminescent decay time measurements, mean lifetimes were $2.3{\sim}2.6ms$ relatively higher than conventional bulk phosphors. These results indicate that $Gd_2O_3:Eu$ nano phosphor is possible for the operation at the low x-ray dose, therefore, the application as medical imaging detector.

• Applied Chemistry for Engineering
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• v.5 no.6
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• pp.981-989
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• 1994

For the development of new material used bentonite in ceramic/organic material composite, ABS(acrylonitrile-butadiene-styrene) material was used as a matrix polymer and a series of bentonite was blended together. This bentonite, filler like talc or mica for plastic material, was used since natural bentonite(Ca type) is easily obtainable in Korea, Na-bentonite changed from natural bentonite by $Na_2CO_3$ based on the specified compositions, changes in the static and dynamic mechanical properties. It was discovered that the increased content of natural and Na- bentonite results in higher modulus with reduced impact strength. And Rockwell hardness was constant. And Na- bentonite filled polymer showed improvement in impact strength and lower in modulus as the natural bentonite filled polymer. The storage modulus(E') of Na- bentonite filled ABS resin was higher than that of Ca- bentonite filled ABS resin, while higher temperature, storage modulus(E') decreased. At higher frequency, tan ${\delta}$ peak was shifted at high temperature.

• Asian-Australasian Journal of Animal Sciences
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• v.22 no.11
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• pp.1574-1580
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• 2009

To evaluate the effect of different housing systems on sow behavior, 80 gilts were randomly allocated at puberty to four treatments: i) sow stall in gestation followed by farrowing crate (SC), ii) group housing with individual feeding in gestation followed by farrowing crate (GC), iii) ESF (Electronic Sow Feeding) system in gestation followed by farrowing crate (EC), and iv) ESF system followed by group farrowing pen (EG). Behavioral observations were carried out on a total of 16 animals per treatment at the following stages: first day of allocation to housing treatment, day of service, 80 days after service, 109 days after service on entry to farrowing accommodation, 24 h before farrowing, day of farrowing, 14, 27 and 28 days after farrowing, at weaning. On each occasion, individual animals were observed for a 24 period with one minute time sampling. There were significant differences (p<0.001) between stages of the reproductive cycle for all the behavior patterns in all treatments. On the first day in experimental housing treatments, sows spent more time rooting and dog-sitting. Activity and investigatory behavior decreased as pregnancy progressed. An activity peak was apparent just before farrowing, followed by a high level of inactivity on the day of farrowing. Time spent active, eating and drinking increased as lactation progressed, and greatest activity and locomotion was seen immediately following weaning. There were significant differences between housing treatments (p<0.01) for standing, moving, eating, drinking, dog-sitting and lying. During pregnancy SC sows spent more time standing, rooting, drinking and dog sitting, while EC sows spent less time rooting and drinking and more time lying. During lactation, GC sows spent more time standing, moving and eating, less time dog sitting and lateral lying. Nursing frequency was reduced in GC sows (p<0.001). The maternal and piglet behaviors were influenced strongly by environment during lactation. However, it was also shown that previous housing history can influence the maternal behavior in the pre-farrowing stage and during early lactation.

• Journal of Microbiology and Biotechnology
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• v.23 no.5
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• pp.681-688
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• 2013

This work is aimed to increase knowledge of the functional exopolysaccharide (EPS) from lactic acid bacteria (LAB) in makgeolli, a Korean fermented rice wine. Among LAB strains isolated from makgeolli, strain M76 was selected as a functional strain producing a bioactive EPS, based on its antioxidative activity on the DPPH radical. The 16S rRNA gene sequencing analysis showed a high sequence similarity (99.0%) with P. acidilactici, but had different biochemical properties with the already known P. acidilactici type strains in the aspect of carbohydrates utilization. The obtained P. acidilactici M76 produced a soluble EPS above 2 g/l. One-step chromatography using gel filtration after ethanol precipitation from the supernatant of P. acidilactici M76 was enough to obtain purified EPS with a single peak, showing a molecular mass of approximately 67 kDa. Componential and structural analyses of EPS by TLC, HPLC, and FT-IR indicated that the EPS is a glucan, consisting of glucose units. The purified EPS had antioxidant activity on the DPPH radical of 45.8% at a concentration of 1 mg/ml. The purified EPS also showed proliferative effect on the pancreatic RIN-m5F cell line and remarkable protection activity on alloxan-induced cytotoxicity. This potent antioxidant and antidiabetic EPS by LAB in makgeolli may contribute to understanding the functionality of makgeolli.

• Journal of Biomedical Engineering Research
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• v.28 no.4
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• pp.530-538
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• 2007

Magnetocardiography (MCG) is a device to measure the magnetic field from the heart. It is a noninvasive device and takes only few minutes to record magnetocardiogram from a subject. In this study, we compared the difference of MCG data recorded from 56 normal subjects in early twenties (28 males and 28 females, mean $age=21.0{\pm}1.6$ years) and 36 elderly subjects (20 males and 16 females, mean $age=61.9{\pm}6.9$ years) for the analysis of the age and gender difference. A total of 24 parameters used in the analysis were derived from QRS complex, R-wave, T-wave, and ST-T period. As a result, seven parameters including maximum current angle and map angle showed the significant difference (p<0.01 and p<0.05, respectively) between young males and young females. Significant difference (p<0.05) between elderly males and elderly females was found from a parameter, pole distance at T-wave peak. In the comparison of age difference, seven parameters regarding current moment, pole distance, and dynamics showed the significant difference between young and elderly males. Eight parameters also showed significant difference (p<0.05) between two younger and elderly female groups. Results showed that parameters regarding current moment, pole distance, and dynamics might be changed when people get older. In conclusion, gender and age difference should be considered when MCG data are analyzed for certain parameters.

• Advances in nano research
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• v.5 no.3
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• pp.261-279
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• 2017

Spectroscopic investigation of Si quantum dots (Si-QDs) embedded in silicon nitride was performed over a broad stoichiometry range to optimize light emission. Plasma-enhanced chemical vapor deposition was used to grow the $SiN_x$ films on Si (001) substrates. The film composition was controlled via the flow ratio of silane ($SiH_4$) and ammonia ($NH_3$) in the range of R = 0.45-1.0 allowed to vary the Si excess in the range of 21-62 at.%. The films were submitted to annealing at $1100^{\circ}C$ for 30 min in nitrogen to form the Si-QDs. The properties of as-deposited and annealed films were investigated using spectroscopic ellipsometry, Fourier transform infrared spectroscopy, Raman scattering and photoluminescence (PL) methods. Si-QDs were detected in $SiN_x$ films demonstrating the increase of sizes with Si excess. The residual amorphous Si clusters were found to be present in the films grown with Si excess higher than 50 at.%. Multi-component PL spectra at 300 K in the range of 1.5-3.5 eV were detected and nonmonotonous varying total PL peak versus Si excess was revealed. To identify the different PL components, the temperature dependence of PL spectra was investigated in the range of 20-300 K. The analysis allowed concluding that the "blue-orange" emission is due to the radiative defects in a $SiN_x$ matrix, whereas the "red" and "infrared" PL bands are caused by the exciton recombination in crystalline Si-QDs and amorphous Si clusters. The nature of radiative and no radiative defects in $SiN_x$ films is discussed. The ways to control the dominant PL emission mechanisms are proposed.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.16
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• pp.6703-6707
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• 2014

Objective: To observe the influence of propofol, isoflurane and enflurance on interleukin-8 (IL-8) and IL-10 levels in cancer patients. Methods: Ninety cancer patients with selective operation from March 2011 to May 2014 were randomly divided into group A (34 cases), group B (28 cases) and group C (28 cases). Intramuscular injections of scopine hydrochloride and phenobarbital sodium were routinely conducted to 3 groups. After general anesthesia was induced, tracheal intubations were given. During the maintenance of anesthesia, 0.5~1.0 mg/kg propofol was intravenously injected to group A discontinuously, while continuous suctions of isoflurane and enflurance were subsequently performed to group B and C correspondingly. Clinical outcomes, postoperative complications as well as serum IL-8 and IL-10 levels before operation (T0), at the time of skin incision (T1), 3 h after the beginning of the operation (T2) and 24 h (T3) and 72 h (T4) after the operation were observed among 3 groups. Results: Operations in all groups were successfully completed. The rates of surgery associated complications were 8.82% (3/34), 7.14% (2/28) and 7.14% (2/28) in group A, B and C, respectively, and there were no significant differences (P>0.05). Serum IL-8 and IL-10 levels increased gradually from the beginning of the operation and reached the peak at T3, and were evidently higher at each time point than at T0 (P<0.01). At T1, serum IL-8 and IL-10 levels had no significant differences among 3 groups (P>0.05), but the differences were significant at T2, T3 and T4 (P<0.05). Moreover, correlation analysis suggested that serum IL-8 level was in positive relation with IL-10 level (r=0.952, P<0.01). Conclusions: Propofol, which is better in inhibiting serum IL-8 secretion and improving IL-10 secretion than isoflurane and enflurance, can be regarded as a preferable anesthetic agent in inhibiting traumatic inflammatory responses.