• Journal of Food Hygiene and Safety
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• v.28 no.1
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• pp.19-23
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• 2013

A simple and rapid method has been developed and validated for simultaneous determination of each macrolides residues (spiramycin, josamycin, tilmicosin, tylosin) in chicken muscle by high-performance liquid chromatography- photo diode array (HPLC-PDA). Chicken muscle sample have been extracted with liquid-liquid extraction process; analytes was extracted by acetonitrile, and then defatted with hexane saturated by acetonitrile. The HPLC separation was performed on a Unison UK-$C_{18}$ ($150mm{\times}3.0mm$, $3{\mu}m$) with a gradient system of 0.1% trifloroacetic acid (TFA) and 0.1% trifloroacetic acid (TFA) in acetonitrile as the mobile phase. The drugs were detected at 232 nm for spiramycin and josamycin, and 287 nm for tilmicosin and tylosin. The limits of quantification (LOQs) were between 27 and $59{\mu}g/kg$; and the intra- and inter-day precision (relative standard deviation; RSD) was between 0.9-13.2 and 2.4-13.1%, respectively in chicken muscle sample. The method may has been successfully applied for multiresidue determination of four macrolides below the maximum residue limits (MRLs) established by the European Union (EU).

• Applied Chemistry for Engineering
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• v.5 no.1
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• pp.160-175
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• 1994

Fibrous potassium hexatitanate whisker with the size of $ID=0.5{\sim}1{\mu}m$ and length=$100{\sim}1000{\mu}m$ (aspect ratio=100~1000) was produced through the reaction between titanium dioxide and potassium carbonate using the slow-cooling calcination followed by water leaching treatment. The optimum condition for the production of fibrous potassium titanate was calcination temperature of $1100^{\circ}C$ for 5hrs, $TiO_2$ mole ratlo to $K_2CO_3$ of 4.5 and slow-cooling rate of $0.5^{\circ}C/min$ to $860^{\circ}C$. Fibrous crystal are grown by the association between the solid potassium titanate and liquid phase during the slow-cooling process. The Proper water leaching condition for removing of K component was leaching time of 10hrs in boiling water. Pressurizing of the mixture of $K_2CO_3$ and $TiO_2$ to be calcinated became effective on the growth of fibrous crystal.

• Journal of Soil and Groundwater Environment
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• v.14 no.6
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• pp.87-94
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• 2009

Surfactant-enhanced air sparging (SEAS) was developed to suppress the surface tension of groundwater prior to air sparging resulting in higher air saturation and larger contact area between NAPL and gas during air sparging. Larger contacting interface between NAPL and gas means faster mass transfer of contaminants from NAPL to gas phase. This new technique, however, is limited to relatively volatile contaminants because vaporization is its basic mechanism of mass transfer. In this study, SEAS was tested at an elevated temperature for a semi-volatile n-decane, which is expected not to be a good candidate of SEAS application due to its low vapor pressure at ambient temperature. Three sparging experiments were conducted using 1-dimensional column (5 cm id, 80 cm length) packed with sand; (1) ambient temperature ($23^{\circ}C$), column saturated with distilled water, (2) SEAS at ambient temperature ($23^{\circ}C$), for n-decane contaminated sand, (3) SEAS at elevated temperature ($73^{\circ}C$), for n-decane contaminated sand. Higher air saturation was achieved by SEAS compared to that by air sparging without surfactant application. The n-decane removal efficiency of SEAS at elevated temperature was significantly higher(> 10 times) than that of ambient SEAS. The n-decane concentrations in the gas effluent from column during SEAS at $73^{\circ}C$ are found to be 10 times of those measured at ambient temperature. Thus, SEAS technique can be applied for removal of semi-volatile contaminants provided that an appropriate technique for elevating aquifer temperature is available.

• The Korean Journal of Pesticide Science
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• v.2 no.1
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• pp.59-64
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• 1998

In order to elucidate the leaching behaviour of the herbicide bentazon in soil, soil columns(5cm ID ${\times}$ 34 cm L) were packed with three different soils up to 30 cm height, followed by the treatment of [$^{14}C$]bentazon, and rice plants(Oryza sativa L.) were grown for 9 weeks on these columns, with the columns without growing rice plants as the control for comparison. The amounts of $^{14}C$ activities percolated were about 92% of the originally applied $^{14}C$ irrespective of the physicochemical properties of the soils in the absence of rice plants, whereas $21{\sim}50%$ of the originally applied $^{14}C$ was percolated in the presence of rice plants, suggesting that the amounts of $^{14}C$ leached decreased remarkably in rice-cultivating soils. Bentazon leached faster in soil with higher pH and with lower organic matter content in the presence of growing rice plants. The amounts of $^{14}CO_{2}$ evolved from the soil columns were less than 0.2% of the originally applied $^{14}C$. Smaller amounts of $^{14}C$ were translocated into shoots via roots in soils with higher organic matter content. $^{14}C$ activities distributed into the aqueous phase of the leachate collected from the soil columns increased with leaching period and by rice cultivation, whereas the physico-chemical properties of soils did not exhibit any effect. The amounts of soil-bound residues increased remarkably by cultivating rice plants.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.15 no.2
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• pp.23-36
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• 2005

The main obstacle hindering the wide deployment of identity-based cryptosystem is that the entity responsible for creating the private key has too much power. As a result, private keys are no longer private. One obvious solution to this problem is to apply the threshold technique. However, this increases the authentication computation, and communication cost during the key issuing phase. In this paper, we propose a new effi ient model for issuing multiple private keys in identity-based encryption schemes based on the Weil pairing that also alleviates the key escrow problem. In our system, the private key of a user is divided into two components, KGK (Key Description Key) and KUD(Key Usage Desscriptor), which are issued separately by different parties. The KGK is issued in a threshold manner by KIC (Key Issuing Center), whereas the KW is issued by a single authority called KUM (Key Usage Manager). Changing KW results in a different private key. As a result, a user can efficiently obtain a new private key by interacting with KUM. We can also adapt Gentry's time-slot based private key revocation approach to our scheme more efficiently than others. We also show the security of the system and its efficiency by analyzing the existing systems.

• Journal of Intelligence and Information Systems
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• v.21 no.3
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• pp.1-17
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• 2015

In this paper, we report what we have observed with regards to a prediction model for the military based on enlisted men's internal(cumulative records) and external data(SNS data). This work is significant in the military's efforts to supervise them. In spite of their effort, many commanders have failed to prevent accidents by their subordinates. One of the important duties of officers' work is to take care of their subordinates in prevention unexpected accidents. However, it is hard to prevent accidents so we must attempt to determine a proper method. Our motivation for presenting this paper is to mate it possible to predict accidents using enlisted men's internal and external data. The biggest issue facing the military is the occurrence of accidents by enlisted men related to maladjustment and the relaxation of military discipline. The core method of preventing accidents by soldiers is to identify problems and manage them quickly. Commanders predict accidents by interviewing their soldiers and observing their surroundings. It requires considerable time and effort and results in a significant difference depending on the capabilities of the commanders. In this paper, we seek to predict accidents with objective data which can easily be obtained. Recently, records of enlisted men as well as SNS communication between commanders and soldiers, make it possible to predict and prevent accidents. This paper concerns the application of data mining to identify their interests, predict accidents and make use of internal and external data (SNS). We propose both a topic analysis and decision tree method. The study is conducted in two steps. First, topic analysis is conducted through the SNS of enlisted men. Second, the decision tree method is used to analyze the internal data with the results of the first analysis. The dependent variable for these analysis is the presence of any accidents. In order to analyze their SNS, we require tools such as text mining and topic analysis. We used SAS Enterprise Miner 12.1, which provides a text miner module. Our approach for finding their interests is composed of three main phases; collecting, topic analysis, and converting topic analysis results into points for using independent variables. In the first phase, we collect enlisted men's SNS data by commender's ID. After gathering unstructured SNS data, the topic analysis phase extracts issues from them. For simplicity, 5 topics(vacation, friends, stress, training, and sports) are extracted from 20,000 articles. In the third phase, using these 5 topics, we quantify them as personal points. After quantifying their topic, we include these results in independent variables which are composed of 15 internal data sets. Then, we make two decision trees. The first tree is composed of their internal data only. The second tree is composed of their external data(SNS) as well as their internal data. After that, we compare the results of misclassification from SAS E-miner. The first model's misclassification is 12.1%. On the other hand, second model's misclassification is 7.8%. This method predicts accidents with an accuracy of approximately 92%. The gap of the two models is 4.3%. Finally, we test if the difference between them is meaningful or not, using the McNemar test. The result of test is considered relevant.(p-value : 0.0003) This study has two limitations. First, the results of the experiments cannot be generalized, mainly because the experiment is limited to a small number of enlisted men's data. Additionally, various independent variables used in the decision tree model are used as categorical variables instead of continuous variables. So it suffers a loss of information. In spite of extensive efforts to provide prediction models for the military, commanders' predictions are accurate only when they have sufficient data about their subordinates. Our proposed methodology can provide support to decision-making in the military. This study is expected to contribute to the prevention of accidents in the military based on scientific analysis of enlisted men and proper management of them.

• Journal of Chest Surgery
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• v.36 no.2
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• pp.63-72
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• 2003

Although a variety of synthetic vascular grafts are available in modern vascular surgery, no ideal prosthesis ha,4 yet been developed. Small-caliber vascular grafts with low flow, as used in the lower extremity, continue to become thrombosed at unacceptable rates. We have developed and evaluated the new antithrombogenic blood contacting surfaces in canine model. Material and Method: Two now antithrombogenic blood contacting surfaces(Polyvinylalcohol -Polyurethane(PVA-PU) blend and natural Graphite-polyurethane(G-PU) blend) have been developed and evaluated in canine model, using vascular grafts and patches. The luminal surfaces of the test vascular grafts(5 mm ID) were fabricated by dipping a glass rod in PVA-PU blend solution(50 % PVA) using phase separation method. Mongrel dogs of either sex weighing 18-22 kg were anesthetized by endotracheal intubation using halothane and their lungs were ventilated with a volume-cycled ventilator, Maintenance anesthesia with 0.5-1.0% halothane and supplemental oxygen was used. Two pairs were used for comparison in the bilateral femoral arteries for both vascular grafts(PVA-PU vs. PU) and vascular patches(G-PU vs. PU). Bilateral groin incisions were made and the arteries were exposed and clamped. After an excision of 1 cm of the artery between clamps, a grail of 2.5 cm in length was implanted end-to-end using 6-0 polypropylene suture. The vascular patch was implanted as a form of on-lay patch. Animals were sacrificed at 1, 2, 4, 6, 8 and 16 weeks for vascular grafts and 1, 2. 4 and 6 weeks for vascular patches. Result The vascular grafts of PVA-PU blends showed patent lumina in the 2 and 16 weeks animals, while those of PU showed a patent lumen in 2 weeks animal. PVA-PU graft of 16 weeks showed a fairly clean luminal surface. A light microscopic finding of this graft demonstrated good tissue infiltration through porosity, The animals with vascular patches showed patent arteries in both groups except 2 weeks animal. Scanning electron microscopy of the luminal surfaces of G-PU patches in 4 and 6 weeks animals showed endothelial cell covering with microvilli. PU patches showed qualitatively less endothelial cell covering. Conclusion: In conclusion, PVA-PU and G-PU blends can be a promising blood contacting surfaces for application in a synthetic vascualr graft. However, further animal study is needed to determine the real long-term effects of these methods of surface modifications.

• Korean Journal of Food Science and Technology
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• v.44 no.3
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• pp.263-268
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• 2012

Novobiocin is a coumarin-containing antibiotic, and has a longer half-life in various animals than other veterinary medicines. A simple and rapid high-performance liquid chromatography assay for the determination of residual novobiocin levels in chicken, beef and milk has been developed and validated. The separation condition for HPLC/UVD was optimized by a MG II $C_{18}$ (4.6 mm $ID{\times}250$ mm, 5 ${\mu}m$) column with 0.1% formic acid in $H_2O$/0.1% formic acid in Acetonitrile (40/60, v/v) as the mobile phase at a flow rate of 1.0 mL/min and the detection wavelength was set at 340 nm. Residues were extracted from tissue by blending with methanol. After liquid-liquid partitioning, lipid materials were removed with n-hexane and purification as Silica (1 g, 6 mL) cartridge with 10 mL acetone/dichloromethane (10/90, v/v). Limit of quantification and linearity performed by the analytical method were 0.02 mg/kg and 0.999 ($r^2$), and the recovery range was $88.8{\pm}5.6-100.3{\pm}4.4$, $88.8{\pm}7.2-97.0{\pm}3.2$ and $88.1{\pm}4.3-92.8{\pm}3.6%$. It is expected that this analytical method with regards to novobiocin in chicken, beef and milk could be applied as an official method to administer food safety on veterinary medicines.

• KSBB Journal
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• v.18 no.3
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• pp.211-216
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• 2003

The removal yield of dissolved organic matter in drinking water by biological activated carbon (BAC) process was investigated. The tested processes wer raw water-AC process (BAC1), raw water-ozonation-BAC process (BAC2), and raw water-ozonation-coagulation/sedimentation-BAC process (BAC3). The amounts of organic matter was measured as dissolved organic carbon (DOC), ulta-violet radiation at 254 nm wavelength ($UV_{254}$), total nitrogen (T-N), ammonia nitrogen (NH_3$-N), and total phosphate (T-P). As a results, 30.7% DOC was removed by BAC2 process, which showed higher removal efficiency than BAC1 or BAC3 processes. The removal yield of $UV_{254}$ in BAC1, BAC2, and BAC3 processes were observed as 45.3%, 44.6%, 58.4%, respectively. And the removal yield of ammonia nitrogen were 66%, 81%, 29% in each BAC processes. The optimal empty bed contact time (EBCT) of BAC processes was estimated as 10 minute. This study has shown that BAC process combined with ozone treatment was efficient for removing dissolved organic matter in water.

• Journal of Food Hygiene and Safety
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• v.19 no.1
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• pp.12-18
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• 2004

Ofloxacin, norfloxacin, ciprofloxacin, and enrofloxacin in chicken muscle were seperated by liquid extraction and determined with high performance liquid chromatography (HPLC) with fluorescence detector. Analysis was carried out using following conditions; Cl8 column (250${\times}$4.6 mm i.d. 5 ${\mu}{\textrm}{m}$ particle size), mobile phase composed of D.W. (containing 0.4% triethylamine and phospholic acid): methanol : acetonitrile (800:100:100, v/v/v), isocratic pump at a flow rate of 1.0 $m\ell$/min and 50 ${mu}ell$ of injection volume, fluorescence detector with EX278 nm/EM.456 nm. The calibration curves of four fluoroquinolones showed linearity (${\gamma}$$^2$$\geq$0.999) at concenration range of 0.025-0.6 $\mu\textrm{g}$/ml. The recoveries in fortified chicken muscle represented more than 80% with low coefficient of variation (〈10%) for concentration range of four fluoroquinolones. The detection limits for ofloxacin, norfloxacin, ciprofloxacin, and enrofloxacin were 23.5, 3.4, 3.0 and 2.5 ng/g in chicken muscle, respectively. We also monitored fluoroquinolones residue in muscle of chickens (broiler 1:227, Korean native chicken 219, laying chicken 77) using EEC-4-plate screening and HPLC conformation methods. Ten(broiler 5, Korean native chicken 5) out of the fifteen samples which were positively detected by EEC-plate screening method from 1,523 chicken meat were confirmed with ciprofloxacin and enrofloxacin by HPLC. The ranges of residual concentration were 0-0.12 ppm for ciprofloxacin and 0.01-6.79 ppm for enrofloxacin. In conclusion, our method could be applied effectively to determine four fluoroquinolones residues in chicken meat, and further survey for fluoroquinolones residue in chicken meat are needed for more effective control of fluoroquinolones used in livestock.