• Journal of Korean Academy of Nursing Administration
• /
• v.8 no.4
• /
• pp.535-549
• /
• 2002

Purpose : The purpose of this study was to develop a core competency evaluation tool of the preceptors training new graduate nurses and to determine the validity of the developed instrument. Method : This study was conducted in 2 phases. In phase I, preceptor's core competency list was developed through literature review, focus group interview, and review by nursing directors and nurse managers. In phase II, 60 preceptors were evaluated with the developed instrument and categorized into excellent, good & poor core competency groups. For validation of the instrument, new graduates' clinical performance improvement and satisfaction with preceptor were compared between excellent and poor group. Result : The data were analyzed by SPSS P.C and the results were as follows. 1) Preceptor's core competencies were classified into three domains; Role model(10 items), Socialization facilitator(8 items), and Educator(16 items), and each item had four point system of "strongly agree" to "strongly disagree". Cronbach'${\alpha}$ of the instrument was.9416. 2) Comparison of clinical performance improvement and satisfaction with preceptor of the new graduates trained by excellent and poor preceptors revealed that new graduates' clinical performance improvement(p=.015) and satisfaction with the preceptor(p=.005) were significantly higher in the excellent core competency preceptor group than the poor core competency preceptor group. Conclusion : The validity of the preceptor's core competency evaluation tool developed in this study was confirmed. Therefore, this tool can be effectively utilized for education and evaluation of new graduates' preceptors in clinical settings.

• Journal of the Korean Society for Heat Treatment
• /
• v.30 no.6
• /
• pp.279-284
• /
• 2017

Mechanical properties of titanium alloy can be improved by controlling microstructure through heat treatment. In this study, Ti-3Al-8V-6Cr-4Mo-4Zr metastable beta titanium alloy, was controlled for excellent mechanical property and sound formability through various high temperature heat treatment and aging conditions and the optimum heat treatment conditions were determined. The specimens were heat-treated at $950^{\circ}C$, followed by various aging treatments from $430^{\circ}C$ to $500^{\circ}C$ for 1 to 24 h. As aging temperature and holding time increased, hardness increased by ${\beta}^{\prime}$ phase formation and precipitation of secondary ${\alpha}$ phase in ${\beta}$ matrix. However, the optimum aging temperature and holding time for mechanical properties were at $450{\sim}470^{\circ}C$ for 8~16 hr. Hardness values of the specimen aged at $450^{\circ}C$ for 8 h were found to be the highest. These results can be effectively applied to fabrication of spring with better formability and mechanical property.

• Journal of Embryo Transfer
• /
• v.31 no.3
• /
• pp.199-205
• /
• 2016

The aim of this study was to investigate the effect of uterine histotroph on embryo development and the expression of cysteine-rich protein 2 (CRP2), coatomer subunit gamma-2 (G2COP), myoglobin (MYG), vascular endothelial growth factor D (VEGFD), collagen alpha 4 chain (COL4) and galactoside 3-L-fucosyltransferase 4 (FUT4) proteins in porcine embryo during pre-implantation. Uterine histotroph (UH) was collected from uterine horn on corpus albican phase, and embryos were cultured in porcine zygote medium with UH for 168 hours. Cleavage and blastocyst formation of embryo were detected at 168 hours after in vitro fertilization. And CRP2, G2COP, MYG, VEGFD, COL4 and FUT4 proteins were observed using confocal laser microscope. In results, embryo cleavage rate was not significantly changed by UH, but blastocyst rate was significantly (P<0.05) decreased in UH-treated embryos. Moreover, CRP2, G2COP, MYG, VEGFD, COL4 and FUT4 proteins were expressed in blastomere. CRP2 in embryo was significantly overexpressed (P<0.05), but not G2COP, MYG, VEGFD, COL4 and FUT4 proteins. In summary, UH on corpus albican phase was increased CRP2 protein in embryo, and inhibited blastocyst formation in preimplantation porcine embryos, suggesting that CRP2 may play an interrupter on embryo development in pigs.

• The Transactions of the Korean Institute of Electrical Engineers C
• /
• v.52 no.2
• /
• pp.80-84
• /
• 2003

The mechanical and electrical properties of the hot-pressed and pressureless annealed SiC-Ti $B_2$electroconductive ceramic composites were investigated as functions of the liquid additives of $Al_2$ $O_3$+ $Y_2$ $O_3$. The result of phase analysis for the SiC-Ti $B_2$ composites by XRD revealed $\alpha$-SiC(6H), Ti $B_2$, and YAG(A $l_{5}$ $Y_3$ $O_{12}$ ) crystal phase. The relative density of SiC-Ti $B_2$ composites was increased with increased $Al_2$ $O_3$+ $Y_2$ $O_3$ contents. The fracture toughness showed the highest value of 6.04 Mpa $m^{\frac{1}{2}}$ for composites added with l2wt% A1$_2$ $O_3$+ $Y_2$ $O_3$ additives at room temperature. The electrical resistivity showed the lowest value of 6.2$\times$10$^{-3}$ $\Omega$ㆍcm for composite added with l6wt% $Al_2$ $O_3$+ $Y_2$ $O_3$ additives at room temperature. The electrical resistivity of the SiC-Ti $B_2$ composites was all positive temperature cofficient resistance(PTCR) in the temperature ranges from $25^{\circ}C$ to $700^{\circ}C$.

• Korean Journal of Materials Research
• /
• v.22 no.3
• /
• pp.150-154
• /
• 2012

Ti-6Al-4V ELI (Extra Low Interstitial) alloy have been widely used as alternative to bone due to its excellent biocompatibility, although it still has many problems such as high elastic modulus and toxicity. Therefore, biomaterials with low elastic modulus and non toxic characteristics have to be developed. A novel ${\beta}$ Ti-35wt%Nb-7wt%Zr-Calcium pyrophosphate (CPP) composite that is a biocompatible alloy without elemental Al or V was fabricated by spark plasma sintering (SPS) at $1000^{\circ}C$ under 70 MPa using high energy mechanical milled (HEMM) powder. The microstructure and phases of the milled powders and the sintered specimens were studied using SEM, TEM, and XRD. Ti-35wt%Nb-7wt%Zr alloy was transformed from ${\alpha}$ phase to ${\beta}$ phase in the 4h-milled powder by sintering. The sintered specimen using the 4h-milled powder showed that all the elements were distributed very homogeneously and had higher density and hardness. ${\beta}$ Ti alloy-CPP composite, which has nanometer particles, was fabricated by SPS using HEMMed powder. During the sintering process, $CaTiO_3$, TixOy, and CaO were formed because of the reaction between Ti and CPP. The Vickers hardness of the composites increases with the increase of the milling time and the addition of CPP. The biocompatibility of the Ti-Nb-Zr alloys was improved by addition of CPP.

• Korean Journal of Clinical Pharmacy
• /
• v.20 no.2
• /
• pp.128-137
• /
• 2010

This review summarizes gender differences in pharmacokinetics, pharmacodynamics, and adverse drug reactions. Gender differences in pharmacokinetics are categorized by four major factors: absorption/bioavailability, distribution, metabolism, and elimination. There are sex-based differences in gastric emptying time, gastric alcohol dehydrogenase activity, apparent volume of distribution, ${\alpha}1$-acid glycoprotein level, phase I (CYP) and phase II metabolizing enzymes, glomerular filtration rate, and drug transporters. This review also reports gender differences in pharmacokinetics and pharmacodynamics of cardiovascular agents, central nervous system acting agents and antiviral agents. In addition, it has been reported that females experience more adverse reactions such as coughing, tachycardia, nausea, vomiting, rash, hypersensitivity, hepatotoxicity, and metabolic disorder after taking cardiovascular, central nervous system acting and antiviral agents. Therefore, in order to provide optimal drug dosage regimens both in male and female, gender differences in pharmacokinetics, pharmacodynamics, and adverse drug reactions must be considered.

• Journal of the Korean Ceramic Society
• /
• v.35 no.3
• /
• pp.280-286
• /
• 1998

LaAlO3 Single crystals used as a substrate for thin film depositions of a high temperature oxide su-perconductor YB2Cu3O7 and applied to microwave frequencies were grown by the Traveling Solvent Flati-ing Zone (TSFZ) method and characterized. For the growth of LaAlO3 single crystals polycrystalline fe-edrods were prepared from powder mixture of La2O3 and Al2O3 with a mole ratio of 1:1 calcined at 110$0^{\circ}C$ for 3h and sintered at 140$0^{\circ}C$ for 4h The growth LaAlO3 crystals was 4-5mm in diameter 30mm in length and dark brown. The growth rate was 2-3mm/h and the rotation speeds were 10rpm for an upper ro-tation and 40 rpm for a lower rotation The growing crystals and the feedrods were counter-rotated. The orientation of the grown single crystals of LaAlO3 was identified to be [111] direction. Dielectric constants were measured to be 30-33 between 100 kHz and 1 MHz in the 30$0^{\circ}C$ to 45$0^{\circ}C$ temperature range and 102 in a range of 100 kHz at the phase transformation temperature of 522$^{\circ}C$ Dielectric losses were calculated to be 1.8$\times$10-4 at the room temperature and 5.7$\times$10-3 at the phase transformation temperature. Lattice con-stants of the grown crystlals were determined to be aR=5.3806 $\AA$ and $\alpha$=60.043$^{\circ}$ by the least square method.

• Analytical Science and Technology
• /
• v.11 no.4
• /
• pp.231-234
• /
• 1998

Separation factor for $^6Li$ and $^7Li$ has been determined using ion exchange resin having 1,7,13-trioxa-4,10,16-triazacyclooctadecane ($N_3O_3$) as an anchor group. The ion exchange capacity of the $N_3O_3$ ion exchanger was 2.0 meq/g dry resin. The lighter isotope, $^6Li$, is concentrated in the fluid phase, while the heavier isotope, $^7Li$, is enriched in the resin phase. By column chromatography [0.3 cm(I.D)${\times}$30 cm (height)] using 3.0 M ammonium chloride solution as an eluent, single separation factor, ${\alpha}$, 1.018, i.e. $(^7Li/^6Li)_{resin}/(^7Li/^6Li)_{fluid}$ was obtained by the Glueckauf theory from the elution curve and isotope ratios.

• Analytical Science and Technology
• /
• v.7 no.2
• /
• pp.201-204
• /
• 1994

Cation exchange column chromatography of lithium was carried out to investigate the lithium isotope separation in aqueous ion exchange system. A Pyrex glass column of $50cm{\times}6mm$ inner radius with a water jacket was used as the separation column in experiment. Upon column chromatography using hydrochloric and succinic acid mixtures as an elunent, single separation factor, ${\alpha}$, 1.0068 was obtained. From the experiment, it was found that $^6Li$ was enriched in the resin phase and $^7Li$ in the solution phase.

• Journal of Microbiology and Biotechnology
• /
• v.11 no.6
• /
• pp.1077-1086
• /
• 2001

The sprA and sprB gene encoding chymotrypsin-like proteases Streptomyces griseus protease A (SGPA) and Streptomyces griseus protease B (SGPB) and the sprT gene that encodes Streptomyces griseus trypsin (SGT) were cloned from Streptomyces griseus ATCC10137 and overexpressed in Streptomyces lividans TK24 as a heterologous host. The chymotrypsin activity of tole culture broth measured with the artificial chromogenic substrate , N-succinyl-ala-ala-pro-phe-p-nitroanilide, was 10, 14 and 14 units/mg in the transformants haboring the sprA, sprB and sprD genes, respectively. The growth of S. lividans reached the maximum cell mass after 4 days of culture, yet SGPA and SGPD production started in the stationary phase of cell growth and kept increasing for up to 10 days of culture in an R2YE medium. The trypsin activity of the culture broth measured with the artificial chromogenic substrate , N-${\alpha}$-benzoyl-DL- arginine-p-nitroanilide , was 16 units/mg and SGT production started in the stationary phase of cell growth and kept increasing for up to 10 days of culture in an R2YE medium. The introduction of the sprA gene into S, lividans TK24 triggered the biosynthesis of pigmented antibiotics, actinorhodin and undecylprodigiosin, and induced significant morphological changes in the colonies in Benedict, R2YE, and R1R2 media. In addition, the introduction of the sprT gene also induced morphological changes in the colony shape without affecting the antibiotic production, thereby implying that certain proteases would appear to play very important and specific roles in secondary-metabolites formation and morphological differentiation in Streptomyces.