• Korean Journal of Veterinary Research
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• v.56 no.4
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• pp.215-221
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• 2016

Due to the shortage of the fingerling/juvenile mud loach, Misgurnus mizolepis in Korea, these fish have been imported from China. However, the mortality rate during and after their transportation is very high. In this study, we examined various physiological and histological parameters to evaluate the effect of salt treatment on the survival and recovery of mud loaches in holding farms during the quarantine process. Glucose, osmolality, $Na^+$, $Cl^-$, and histological changes were assessed for three different salinities. Non-treated fish (control 0.0%) exhibited lower levels of osmolality, and $Na^+$ and $Cl^-$ concentrations compared with those kept in solar salt solution (0.5% and 1.0%). Glucose levels in control fish were higher than those in fish exposed to 0.5% and 1.0% solar salt solution. Histologically, control fish showed thinner epidermis of skin, branchial hyperplasia and lamellar fusion with an abundance of eosinophilic granule cell-like cells. After solar salt solution treatment, damaged gill structures in the fish almost recovered within 5 days. The present study demonstrates that mud loaches transported from China suffer from skin and gill damage and physiological dysfunction which may increase the mortality and morbidity. Moreover, saline treatment might alleviate the stress responses and ionic/osmotic imbalances, and help heal gill damage.

• Analytical Science and Technology
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• v.12 no.3
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• pp.260-264
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• 1999

A simple and rapid procedure, called FoLT-PCR(Formamide Low Temperature-Polymerase Chain Reaction) was applied to amplifying DNA directly from various forensic biological evidences including human blood, saliva, hair root, or semen without any DNA preparative steps. We added washing step with non-ionic detergent, 1% Triton X-100, and used Taq DNA polymerase instead of Tth DNA polymerase to amplify 3 STR loci and gender allele simultaneouly. Optimal concentration of formamide and annealing temperature were determined empirically to 8%(v/v), and $48^{\circ}C$ respectively. We also compared this method with standard PCR.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.34 no.3
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• pp.22-30
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• 2006

In this paper, a systematic design method on an IPMC(ionic polymer-metal composite)-driven ZNMF(zero-net-mass-flux) pump is introduced for the flow control of an MAV's (micro air vehicle) wing. Since the IPMC is able to generate a large deformation under a low input voltage along with its ability to operate in air, and is easier to be manufactured in a small size, it is considered to be an ideal material of the actuating diaphragm. Through the numerical methods, an optimal shape of the IPMC　diaphragm was found for maximizing the stroke volume. Based on the optimal IPMC diaphragm, a proto-type ZNMF pump with a slot, was designed. By using the flight speed of the MAV considered in this work, the driving frequencies(~ 40 Hz) of IPMC diaphragm, and the flow velocity through the pump's slot, the calculated non-dimensional frequency and the momentum coefficient ensure the feasibility of the designed ZNMF pump as a flow control device.

• Korean Journal of Food Science and Technology
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• v.27 no.5
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• pp.658-665
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• 1995

Low yield of a thermostable pectinesterase(TSPE) from citrus fruits has made its detailed study extremely tedious and difficult; therefore, maximizing TSPE extraction is desirable. It is assumed that TSPE is bound to the cell components via ionic linkage and covalent bonds. Therefore, in this study, variations in extraction time, pH, NaCl concentration and commercial enzyme preparations were used to increase the yield of TSPE from Valencia orange. The largest recovery of TSPE, obtained by heating extracted pectinesterase(PE) at $70^{\circ}C\;for\;5{\sim}10$ minute, was achieved using actate buffer(pH 4.14) with 1 M NaCl and 0.2% $Cytolase^{TM}$ 104(a mixture of cellulase, hemicellulase and pectinase; Genecor, Inc). The two aquous phase partitioning with 5.0% Triton X-114 could be used as a tool for separation of thermolabile pectinesterase(TLPE) and TSPE from crude PE. Also, water extraction and $0{\sim}0.3$ ammonium sulfate fractionation could be used for removing non-pectinesterase protein.

• Journal of the Korean Ceramic Society
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• v.45 no.11
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• pp.734-738
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• 2008

Ettringite$(3CaO{\cdot}Al_2O_3{\cdot}3CaSO_4{\cdot}32H_2O)$, one of the hydrated phase of Portland cement is usually formed in the early stage of hydration by the reaction of tricalciumaluminate$(C_3A)$ and gypsum. The rapid and strong crystal growth of separated rod-shaped ettringite have been utilized for the preparation of special cements of rapid setting, high strength and non-shrinking properties. The ettringite also has been noticed as a promising materials for the immobilization of various waste ions because of its unique crystal structure which has abundant channels and exchangeable ionic compounds. In this study, the formation and growth behavior of the ettringite was investigated in the system $C_3A-CaSO_4-H_2O$ using $C_3A$ clinker and gypsum to obtain a microporous body for waste ion immobilization. Ettringite was revealed to form by the dissolution-precipitation mechanism and the bulk body was by the entangled growth of rod-shaped ettringite crystals. The hardened body was composed of nearly pure rod-shaped ettringite interlocked each other with adequate mechanical strength. The homogeneity of structure, pore size, specific surface area and porosity of the hardened body were influenced by reaction temperature, water/powder ratio and the curing time. The hardened body prepared with water/powder ratio of 1 at $24^{\circ}C$ for one day showed excellent morphological properties for the purposed materials.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.24 no.3
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• pp.116-122
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• 1998

It is well known that all-trans-retinol is not only very unstable in heat, light, air, and water, but also skin-irritant despite a good anti-wrinkle effect. Therefore, it is very difficult to stabilize retinol and make the safe retinol containing cosmetics by using a certain concentration of retinol with real effect. In order to dissolve these problems and apply retinol for skin care cream, firstly retinol is to be encapsulated in the vesicle called Liposphere (pseudo-liposome) which is made by homogenizing under high pressure the mixtures of lecithin, retinol, caprylic/capric triglyceride, and hydroalcoholic solution ; and then this retinol containing Liposphere is to be intercalated in lamellar liquid crystal layer which is prepared by emulsifying in an optimal ratio the mixtures composed of non-ionic emulsifier (cetearyl glucoside, sorbitan stearate & sucrose cocoate etc), cetearyl alcohol, stearic acid, cholesterol, and ceramide. In addition, the stability of the retinol containing oil in water cream by adding the polymeric emulsifier such as acrylate /C10-30 alkyl alkylate crosspolymer is to be ensured even at 55 C. Retinol containing oil in water cream prepared through above procedure could be very stable at 45 C for at least 50 days. The structure identification of lamellar liquid crystal was determined using polarized light microscope and electron microscope Conclusively, we could make the very stable retinol containing oil in water cream by triple procedure, that is, encapsulation of retinol in Liposphere, intercalation of retinol in lamellar liquid crystal layer, and assurance of the high temperature stability of cream even at 55 C.

• Korean Journal of Materials Research
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• v.21 no.10
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• pp.568-572
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• 2011

The preparation of $Y_2O_3$-doped $ZrO_2$ nanoparticles in Igepal CO-520/cyclohexane reverse micelle solutions is studied here. In this work, we synthesized nanosized $Y_2O_3$-doped $ZrO_2$ powders in a reverse micelle process using aqueous ammonia as the precipitant. In this way, a hydroxide precursor was obtained from nitrate solutions dispersed in the nanosized aqueous domains of a microemulsion consisting of cyclohexane as the oil phase, with poly (oxyethylene) nonylphenylether (Igepal CO-520) as the non-ionic surfactant. The synthesized and calcined powders were characterized by thermogravimetrydifferential thermal analysis (TGA-DTA), X-ray diffraction analysis (XRD) and transmission electron microscopy (TEM). The crystallite size was found to nearly identical with an increase in the water-to-surfactant (R) molar ratio. A FTIR analysis was carried to monitor the elimination of residual oil and surfactant phases from the microemulsion-derived precursor and the calcined powder. The average particle size and distribution of the synthesized $Y_2O_3$-doped $ZrO_2$ were below 5 nm and narrow, respectively. The TG-DTA analysis showed that the phase of the $Y_2O_3$-doped $ZrO_2$ nanoparticles changes from the monoclinic phase to the tetragonal phase at temperatures close to $530^{\circ}C$. The phase of the synthesized $Y_2O_3$-doped $ZrO_2$ when heated to $600^{\circ}C$ was tetragonal $ZrO_2$.

• Korean Journal of Materials Research
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• v.18 no.5
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• pp.235-240
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• 2008

This paper presents results and observations obtained from a study of the optical and thermal properties of alkali tellurite depending on the composition. Fourier transform infrared (FT-IR) spectra showed evidence of chemical modification from $TeO_4$ trigonal bipyramids (tbp) to $TeO_3$ trigonal pyramids (tp) in tellurite glasses. The optical band gaps of the different glass samples calculated using Tauc's method were found to range from 3.5-3.8 eV. The glass transition temperature (Tg) and glass stability (${\Delta}T$) of alkali tellurite glasses were investigated, as $M_2O$ [M: Li, Na, K] amounted to 25 mol%, through the use of differential thermal analysis (DTA). The coefficient of thermal expansion (CTE) was measured in a thermo mechanical analysis (TMA) with a slow heating rate after the glass samples were annealed. The results confirm that the optical band gap of alkali tellurite glasses depends on the Te-O-Te structural relaxation related to the ratio of bridging/non bridging oxygen (BO/NBO). In contrast, the thermal properties are related to the ionic field strength of the Te-O-M and M-O-M bonds, and the Te-O-Te breakage depends on the ratio of BO/NBO.

• Korean Journal of Materials Research
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• v.23 no.1
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• pp.31-34
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• 2013

Trivalent cerium-ion-doped $Y_3(Al,\;Ga)_5O_{12}$ nanoparticle phosphor nanoparticles were synthesized using the reverse micelle process. The Ce doped $Y_3(Al,\;Ga)_5O_{12}$ particles were obtained from nitrate solutions dispersed in the nanosized aqueous domains of a micro emulsion consisting of cyclohexane as the oil phase and poly(oxyethylene) nonylphenyl ether (Igepal CO-520) as the non-ionic surfactant. The crystallinity, morphology, and thermal properties of the synthesized $Y_3(Al,\;Ga)_5O_{12}:Ce^{3+}$ powders were characterized by thermogravimetry-differential thermal analysis (TGA-DTA), X-ray diffraction analysis (XRD), scanning electron microscopy (SEM), and transmission electron microscopy. The crystallinity, morphology, and chemical states of the ions were characterized; the photo-physical properties were studied by taking absorption, excitation, and emission spectra for various concentrations of cerium. The photo physical properties of the synthesized $Y_3(Al,\;Ga)_5O_{12}:Ce^{3+}$ powders were studied by taking the excitation and emission spectra for various concentrations of cerium. The average particle size of the synthesized YAG powders was below $1{\mu}m$. Excitation spectra of the $Y_3Al_5O_{12}$ and $Y_3Al_{3.97}Ga_{1.03}O_{12}$ samples were 485 nm and 475 nm, respectively. The emission spectra of the $Y_3Al_5O_{12}$ and $Y_3Al_{3.97}Ga_{1.03}O_{12}$ were around 560 nm and 545 nm, respectively. $Y_3(Al,\;Ga)_5O_{12}:Ce^{3+}$ is a red-emitting phosphor; it has a high efficiency for operation under near UV excitation, and may be a promising candidate for photonic applications.

• Korean journal of food and cookery science
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• v.33 no.3
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• pp.256-263
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• 2017

Purpose: Essential oils are secondary metabolites of herbs and have antibacterial activities against foodborne pathogens. However, their applications for food protection are limited due to the hydrophobic and volatile natures of essential oils. Methods: In this study, essential oil nanoemulsions of rosemary and lavender were formulated with non-ionic surfactant Tween 80 and water using ultrasonic emulsification, and their antibacterial effects were determined. Results: The antibacterial activities of nanoemulsions were evaluated against 12 strains of 10 bacterial species, and significant antibacterial effects were observed against four Gram-positive and four Gram-negative bacteria but not against Streptococcus mutans and Shigella sonnei. In the disc diffusion test, the diameter of the inhibition zone proportionally increased with the concentration of nanoemulsions. Using cell turbidity measurement, minimum bactericidal concentration (MBC) of the nanoemulsions, which is the lowest concentration reducing viability of the initial bacterial inoculum by ${\geq}99.9%$, was significantly higher than the minimum inhibitory concentration (MIC) of the nanoemulsions. The largest bactericidal effects of lavender and rosemary essential oil nanoemulsions were observed against S. enterica and S. aureus, respectively. Conclusion: Nanoemulsion technique could improve antibacterial activity of essential oil nanoemulsions by increasing the solubility and stability of essential oils. Our findings shed light on the potential use of essential oil nanoemulsions as an alternative to chemical sanitizers in food protection.