• Journal of the Earthquake Engineering Society of Korea
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• v.10 no.4 s.50
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• pp.77-84
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• 2006

Recently, as large structures such as high-rise building and long span bridge become lighter and more flexible, the necessity of structural control for reducing excessive dynamic response due to seismic excitation is increased. In this study, a semi-active base isolation system using Magneto-Sensitive (MS) rubbers is proposed to effectively protect structures against earthquakes. MS Rubber is a class of smart controllable materials whose mechanical properties change instantly by the application of a magnetic field. To demonstrate the performance of this device, the MS Rubber isolation system is compared to Lead-Rubber Bearing (LRB) isolation systems and judged based on computed responses to several historical earthquakes. The MS Rubber isolation system is shown to achieve notable decreases in base drifts over comparable passive systems with no accompanying increase in base shears or in accelerations imparted to the superstructure. The proposed MS Rubber system is shown to perform better than the passive isolation system.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.42 no.1
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• pp.15-19
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• 2009

A simple and sensitive method for erythromycin quantification by liquid chromatography electrospray mass spectrometry (LC-MS/MS) in fishery products was developed. Samples were extracted by liquid-liquid extraction using 70% acetonitrile. Lipids were removed by acetonitrile saturated hexane. LC separation was performed on a Shiseido UG C-18 column ($150\;mm{\times}2.0\;mm$ internal diameter.) with a gradient system of 0.2% acetic acid-acetonitrile containing 0.2% acetic acid as a mobile phase at flow rate of 0.2 mL/min. The mass spectrometer was operated in selected reaction monitoring with positive electro-spray interface. Transitions were monitored a m/z $734{\to}577$ and $734{\to}158$, with m/z $734{\to}577$ chosen for quantification. Recovery of erythromycin from fish and shrimp fortified at the 10 ng/mL, 50 ng/mL and 100 ng/mL were 91.6-109.4%, 84.4-111.2% and 98.8-109.6% with high precision, respectively. Limits of quantification and limits of detection of erythromycin in both fish and shrimp were 10.0 ng/mL and 1.0 ng/mL, respectively. This analysis method for erythromycin has been proposed for registration in the Korean Official Methods of Food Analysis and has been utilized for fishery products analysis by the Korea Food and Drug Adminstration and the National Fisheries Products Quality Inspection Service.

• Plant Biotechnology Reports
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• v.3 no.1
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• pp.67-74
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• 2009

An efficient micropropagation protocol based on multiple shoot induction and callus regeneration has been standardized in Sarcostemma brevistigma, a rare medicinal plant. The nodal cuttings were cultured on MS medium supplemented with BA ($0.5-8{\mu}M$) or Kn ($0.5-8{\mu}M$) alone or in combination with NAA ($0.5-1.5{\mu}M$). Maximum multiple shoot induction was observed on MS medium supplemented with $4{\mu}M$ BA. On this medium, 100% cultures responded with an average number of 11.3 shoots per explant. However, the average shoot length was limited to only 0.9 cm on this medium. The addition of $1{\mu}M$ NAA along with $4{\mu}M$ BA gave rise to an average number of 10.9 shoots with an average shoot length of 1.8 cm. Luxuriantly growing callus was obtained on MS medium supplemented with BA ($5{\mu}M$) and 2,4-D ($2{\mu}M$). The callus was subcultured on MS medium supplemented with BA ($2-15{\mu}M$) or Kn ($2-15{\mu}M$) alone or in combination with NAA ($0.5-2{\mu}M$) for shoot organogenesis. Optimum callus regeneration was obtained on MS medium supplemented with $10{\mu}M$ BA and $1{\mu}M$ NAA. On this medium, 100% cultures responded with an average number of 13.4 shoots per culture. The shoots obtained via multiple shoot induction and organogenesis were rooted on half-strength MS medium supplemented with NAA ($1-7{\mu}M$) or IBA ($1-7{\mu}M$). IBA was better than NAA in terms of both the percentage of cultures that responded and the average number of roots per explant. The rooted shoots were successfully transplanted to soil with 86% success. This standardized protocol will help to conserve this rare medicinal plant.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.41
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• pp.51.1-51.8
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• 2019

Purpose: It has been reported before that the amount of pharyngeal airway space (PAS) significantly decreases following mandibular setback (MS) surgery in patients with mandibular prognathism (MP). Further, MP patients with an anterior open-bite (AOB) presentation may show a larger decrease in PAS compared with those without AOB. However, studies on postoperative PAS changes in MP patients with AOB remain rare. This study sought to evaluate changes in PAS and hyoid bone positioning following MS surgery in MP patients with and without AOB. Patients and methods: Twenty patients who underwent two jaw surgery involving MS movement were included. Patients were divided into a non-AOB group (n = 10; overbite > 2 mm) and an AOB group (n = 10; overbite < - 4 mm). Three-dimensional changes in PAS and hyoid bone positioning were compared and statistically evaluated pre- and postoperatively using computed tomography (CT). Results: The mean magnitude of MS was 6.0 ± 2.8 mm and 5.6 ± 3.2 mm in the non-AOB group and AOB group, respectively. The oropharyngeal volume and upper hypopharyngeal volume were significantly reduced after surgery in both the groups (p = 0.006 and p = 0.003), while the retroglossal cross-sectional area was significantly reduced only in the AOB group (p = 0.028). Although the AOB group showed a larger decrease in PAS, the difference was not statistically significant between the groups. The position of the hyoid bone showed significant posterior and inferior displacement only in the AOB group, while the vertical displacement of the hyoid bone showed a statistically significant difference between the two groups. Conclusion: PAS was significantly decreased after MS in both the groups, while only the AOB group presented a statistically significant reduction in the retroglossal cross-sectional area. Vertical displacement of the hyoid bone showed a statistically significant difference between the groups, while the PAS change was not. Surgeons should be aware of potential postoperative airway problems that may arise when performing MS surgeries.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.20
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• pp.8797-8800
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• 2014

Objective: To analyze cost-effectiveness of morphine, MS contin and oxycodone in the treatment of cancer pain, providing guidance for rational drug use in the clinic. Methods: Confirmed by histology, a total of 171 patients with various cancers who required analgesic treatment were selected and divided into 3 groups, 57 cases for each group, given morphine, MS contin and oxycodone, respectively. If there appeared a poor short-term effect or aggravated sudden pain during the treatment, a short-acting morphine injection was given and adverse reactions were processed by symptomatic treatment. The pain relief rate and adverse reactions of groups were observed and pharmacoeconomics evaluation was undertaken. Results: The pain relief rates with morphine, MS contin and oxycodone were 89.5%(51/57), 91.2%(52/57) and 93.0%(53/57), respectively, with no difference samong groups (${\chi}^2=4.4489$, P=0.6162). The occurrence rates of adverse reactions were 59.7%(34/57), 54.4%(31/57) and 43.9%(25/57), again with no significant variation (P>0.05). The ratios of cost-effectiveness (C/E) for the 3 groups were $14.6{\pm}7.21$, $15.0{\pm}7.44$ and $16.1{\pm}8.10$. When the price of 3 kinds of analgesics was reduced by 10%, the ratios of cost-effectiveness were $12.2{\pm}6.53$, ($13.4{\pm}6.08$ and $14.5{\pm}6.74$ but there was no differences when compared with before the price adjustment (t=1.86, P=0.0651; t=1.30, P=0.1948; t=1.17, P=0.2453). Conclusion: Morphine, MS contin and oxycodone give similar pain relief and adverse reaction rates but of all, morphine is the preferred drug for the treatment of cancer pain from the perspective of pharmacoeconomics.

• Journal of the Korean Wood Science and Technology
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• v.1 no.2
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• pp.3-10
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• 1973

This study was carried out to examine the characeristics of waste sanders(S)from. plywood and pre-finishing plywood surface sanding and double saw finishing, as a new extander in urea-formaldehyde resin(UFR) in plywood adhesive, and to focus, adhesive strength using the glue extended with milled sanders(MS) as extender, leveling the optimum amount of MS to be added, and examining the physical properties of glue extended MS & S. Also economical good feasibility of substitution for wheat flour(WF) with MS as a new extender is analyzed and presented in details. Selecting three standard samples of 80, 100 and 180 mesh, sorking them in distilled water at $20^{\circ}C$, 24 hours, redrying at $105^{\circ}C$ and rescreening the sample with standard screen, again, the 3 samples of 80, 100, and 180 mesh are passed 23 percent through 80 mesh sander standard sample 27 percent through on 100 mesh and only 10.9 percent through 180 mesh, respectively. The particle size of retained parts are greater in size of redried form. It seems undoubtly that particles to be extended in glue are got swollen and become greater in size and coarser in shape. The shape of fresh S particles are irregular thin needle with small scale, as shown in Figure 5. PFS are so finer than plywood S that only 9.8 percent of the S retained on 100 mest screen, 24. 30 percent on 100-160 mesh, and 65.9% on 160-180 mesh. But particle size of the fresh S is large enough to make the viscosity of glue direct extended with S too high to apply it glue spreader. The glue extended with milled sanders(MS). 3 hours milled PFS or 6 hours milled plywood S, having particle sizes shown in Tables 7 and 8, as ratio of Reain/MS/WF/water: 100/8/8/10, indicate good viscosity of 16 to 24 ps, as shown in Figure 5, for applying direct to glue spreader, have high tensile-shear strength (adhesive strength), 102.4 kp/$cm^2$, and 94 percent wood failure.

• Analytical Science and Technology
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• v.28 no.1
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• pp.1-7
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• 2015

4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK), a tobacco specific nitrosamine found only in tobacco products. The ability to monitor biomarker concentrations is very important in understanding environmental tobacco smoke (ETS). In this study, an efficient and sensitive method for the analysis of NNK in dust was developed and validated using liquid chromatography tandem mass spectrometry. Dust was collected with filter paper soaked in methanol. The standard solution and dust sample were diluted with 100 mM ammonium acetate and extracted using dichloromethane. Our calibration curves ranged from 25 to $10^4pg/mL$. Excellent linearity was obtained with correlation coefficient values between 0.9996 and 1.0000. The limit of detection (LOD) was 5 pg/mL ($S/N{\geq}3$) and the retention time was 10 min. The limit of quantification (LOQ) was 25 pg/mL, and the acceptance criteria was the rate of 98-103% (80-120% at levels up to $3{\times}LOQ$). The coefficient of variations (CV) was 2.8%. Accuracies determined from dust samples spiked with four different levels of NNK racurves ranged that from 25 to 104 pg/mL. Excellent linearity was obtained between 92.1% and 114%. The precision of the method was acceptable (5% of CV). The recovery rates of the whole analytical procedure at low, medium, and high levels were 105.7-116.5% for NNK. The carry-over effects during LC-MS/MS analysis were not observed for NNK. This manuscript summarizes the scientific evidence on the use of markers to measure ETS.

• Bulletin of the Korean Chemical Society
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• v.25 no.10
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• pp.1477-1483
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• 2004

We present the tandem mass spectrometry applications carried out to elucidate the coordination structure of Zn(II) bound lysine ternary complexes, $(Zn+Lys+Lys-H)^+$, which is a good model system to represent a simple (metallo)enzyme-substrate complex (ES). In particular, experimental efforts were focused on revealing the involvement of a lysine side chain ${\varepsilon}$-amino group in the coordination of $Zn^{2+}$ divalent ions. MS/MS fragmentation pattern showed that all the oxygen species within a complex fell off in the form of $H_2O$ in contrast to those of other ternary complexes containing amino acids with simple side chains (4-coordinate geometries, Figure 1a), suggesting that the lysine complexes have different coordination structures from the others. The participation of a lysine basic side chain in the coordination of Zn(II) was experimentally evidenced in MS/MS for $N{\varepsilon}$-Acetyl-L-Lys Zn(II) complexes with acetyl protection groups as well as in MS/MS for the ternary complexes with one $NH_3$ loss, $(Zn+Lys+Lys-NH_3-H)^+$. Detailed structures were predicted using ab initio calculations on $(Zn+Lys+Lys-H)^+$ isomers with 4-, 5-, and 6-coordinate structures. A zwitterionic 4-coordinate complex (Figure 7d) and a 5-coordinate structure with distorted bipyramidal geometry (Figure 7b) are found to be most plausible in terms of energy stability and compatibility with the experimental observations, respectively.

• Journal of the Korean Society of Propulsion Engineers
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• v.18 no.6
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• pp.68-74
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• 2014

During the life firing test of 1 N-class thruster development model, pulse mode performance and performance changes were examined. The deviation of pulse mode response time according to thruster feed pressure was relatively small and the resultant ignition delay, response time, tail-off time were 32-35 ms, 86-91 ms, 89-98 ms, respectively. For the stabilized pulse region the impulse bit revealed the outstanding reproducibility of 1.41, 1.32, 2.10% at $3{\sigma}$. During the life firing test, the impulse bit was decreased with limited amounts, therefore the pulse mode performance could be considered to be maintained. The thrust centroid was also maintained during the life firing test.

• Journal of Food Hygiene and Safety
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• v.34 no.4
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• pp.348-353
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• 2019

This study was conducted to monitor the carbendazim residues in soybean and mungbean sprouts using LC-MS/MS method. Eighty-two samples were collected from markets in western Seoul. No carbendazim was detected in mungbean sprouts, however, it was detected in 6 among 59 soybean sprout samples showing a 10.2% of detection rate. Among these 6 carbendazim- detected soybean sprout samples, five exceeded the maximum residue limit presenting 83.3% of violation rate. The mean concentration in the detected samples was 0.063 mk/kg (0.012 ~ 0.104 mg/kg) and 5 of the 6 detected samples came from bulk sold products. None of the samples came from domestic products; three were from imported products and 3 were from unidentified sources. Risk assessment for the carbendazim from soybean sprout dietary intake was deemed safe and at less than 1 %Acceptable Daily Intake.