• Journal of The Korean Association For Science Education
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• v.13 no.3
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• pp.366-376
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• 1993

In this study, a part of high school science instructional materials is evaluated by Instructional Quality Profile(IQP) based on the Merrill's Component Display Theory(CDT). The CDT is based on the Gagne's assumption of different conditions of learning for different outcomes. The IQP enables the user to check both the consistency and adequacy of existing cognitive instruction. The IQP can be used to predict student performance, and also to design and develop new instructional materials. The instructional components are classified according to 5 task levels; An Use-Generalities on Newly Encountered Examples(UGeg), A Remember-Paraphrased-Generalities(RpG), A Remember-Verbatim-Generalities(RvG), A Remember-Paraphrased-Examples (Rpeg). A Remember-Verbatim-Examples (Rveg). The analyses are composed of 3 parts; Justifying the task level of objectives, Objective-test consistency, and Test-presentation consistency. The objectives, the presentations and the tests given in a teacher's guide and a textbook are analyzed. The results show that the task levels and the content levels of the objectives are not consistent with those of the tests. And the indices of the test-presentation consistency indicate the presentation problems of the instructional materials.

• Asian Pacific Journal of Cancer Prevention
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• v.16 no.13
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• pp.5471-5476
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• 2015

2-deoxy-D-Glucose (2DG) causes cytotoxicity in cancer cells by disrupting thiol metabolism. It is an effective component in therapeutic strategies. It targets the metabolism of cancer cells with glycolysis inhibitory activity. On the other hand, MLN4924, a newly discovered investigational small molecule inhibitor of NAE (NEDD8 activating enzyme), inactivates SCF E3 ligase and causes accumulation of its substrates which triggers apoptosis. Combination of these components might provide a more efficient approach to treatment. In this research, 2DG and MLN4924 were co-applied to breast cancer cells (MCF-7 and SKBR-3) and cytotoxic and apoptotic activity were evaluated the by Micro culture tetrazolium test (MTT), TUNEL and ELISA methods. Caspase3 and Bcl2 genes expression were evaluated by real time Q-PCR methods. The results showed that MLN4924 and MLN4924/2DG dose-dependently suppressed the proliferation of MCF7 and SKBR-3 cells. Cell survival of breast cancer cells exposed to the combination of 2DG/MLN4924 was decreased significantly compared to controls (p<0.05), while 2DG and MLN4924 alone had less pronounced effects on the cells. The obtained results suggest that 2DG/MLN4924 is much more efficient in breast cancer cell lines with enhanced cytotoxicity via inducing a apoptosis cell signaling gene, caspase-3.

• Membrane Journal
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• v.18 no.1
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• pp.53-64
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• 2008

Fouling behavior of polyethylene capillary membranes was examined by measuring the flux of bentonite colloidal suspensions through the cross flow micro filtration. The membrane fouling was due to the three mechanisms: the cake formation on the membrane surface, the standard pore blocking and the complete pore blocking by particles. These mechanisms were simultaneously responsible for the membrane fouling, being significantly governed by the cake filtration. In the total fouling at $1.0kg/cm^2$ TMP condition, the complete blocking was 3.36%, the standard blocking 3.18% and the cake filtration 96.05%. For 1000 ppm feed solution, the complete blocking was 1.71% compared with the standard blocking of 1.90% and the cake filtration of 96.39%. And 96.14% of the total fouling was generated at the initial period of filtration. The cake filtration effect was larger on $0.34{\mu}m$ pore membrane than on $0.24{\mu}m$ pore membrane. With the increase in cross flow velocity, the component fouling decreased by 10.20%, and the ratio of pore blocking to total fouling increased.

• Archives of Plastic Surgery
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• v.44 no.4
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• pp.293-300
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• 2017

Background Simulation training is becoming an increasingly important component of skills acquisition in surgical specialties, including Plastic Surgery. Non-living simulation models have an established place in Plastic Surgical microsurgery training, and support the principles of replacement, reduction and refinement of animal use. A more sophisticated version of the basic chicken thigh microsurgery model has been developed to include dissection of a type 1-muscle flap and is described and validated here. Methods A step-by-step dissection guide on how to perform the chicken thigh adductor profundus free muscle flap is demonstrated. Forty trainees performed the novel simulation muscle flap on the last day of a 5-day microsurgery course. Pre- and post-course microvascular anastomosis assessment, along with micro dissection and end product (anastomosis lapse index) assessment, demonstrated skills acquisition. Results The average time to dissect the flap by novice trainees was $82{\pm}24$ minutes, by core trainees $90{\pm}24$ minutes, and by higher trainees $64{\pm}21$ minutes (P=0.013). There was a statistically significant difference in the time to complete the anastomosis between the three levels of training (P=0.001) and there was a significant decrease in the time taken to perform the anastomosis following course completion (P<0.001). Anastomosis lapse index scores improved for all cohorts with post-test average anastomosis lapse index score of $3{\pm}1.4$ (P<0.001). Conclusions The novel chicken thigh adductor profundus free muscle flap model demonstrates face and construct validity for the introduction of the principles of free tissue transfer. The low cost, constant, and reproducible anatomy makes this simulation model a recommended addition to any microsurgical training curriculum.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.34 no.3
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• pp.1-8
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• 2002

The object of this study was to determine the surface energy of hydrophobically modified micro-crystalline cellulose (MCC) with AKD and evaluate the effect of surface energy of the solid particles dispersed in aqueous medium on flotation efficiency. Especially to eliminate the complication derives from the diverse parameters of solid particles including particle size, type, etc. MCC's modified with AKD have been used. The surface energy Parameters were calculated from advancing contact angles of apolar and polar liquids on MCC pellets using the Lifshitz-van der Waals acid-base (LW:AB) approach. Total surface energy of hydrophobic MCC ranged from 46.19 mN/m to 48.60 mN/m. The contribution of the acid-base components to the total surface energy ranged form 13% to 17% for hydrophobic MCC's. The effect of surface characteristics on the flotation efficiency was evaluated. It was shown that there exist critical values of surface energies to increase flotation efficiency. Total surface energy and polar component of solid particles should be lower than 47 mN/m and 7 mN/m, respectively, for effective removal in the flotation process.

• Applied Chemistry for Engineering
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• v.20 no.2
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• pp.177-185
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• 2009

The failure analysis of scales deposited on automotive thermostat housing has been carried out. Observations using energy dispersive spectroscopy and electron probe micro analyzer indicate that the main components of scales are some of additives of coolant used. For a detailed investigation of organic matters pyrolysis-GC/MS is employed. The result shows that the main organic component is benzoic acid and furthermore, a small amount of acetophenone, benzene and phenyl group is detected. Based on the results of failure analysis performed, the scales on automotive thermostat housing appear due to the deposition of coolant components, followed by crevice corrosion, into gap between housing and rubber horse. New accelerated test methodology, which could mimic the scale formation and the crevice corrosion on thermostat housing, is developed considering the above results. In order to reproduce the real operating conditions, the accelerating factors, i.e. temperature and humidity, are changed and programmed. The reproducibility of the accelerated test proposed is confirmed after analyzing the scales obtained from the accelerated test.

• Food Science and Biotechnology
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• v.16 no.6
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• pp.928-934
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• 2007

Physiochemical properties, such as yield and molecular weight distribution of polysaccharide fractions, of polysaccharides in the enzymatic hydrolysates of purslane were investigated and characterized. A higher amount of micro nutrients, such as potassium (9,413 mg/100 g), phosphorus acid (539 mg/100 g), leucine, alanine, lysine, valine, glycine, and isoleucine, was present in whole purslane. The yield of water soluble polysaccharides (WSP) was 0.29, 7.01, and 7.94% when extracted using room temperature water (RTW), hot-water (HW), and hot temperature/high pressure-water (HTPW), respectively, indicating that HW or HTPW extraction may be effective to obtain WSP from purslane. The average ratio of L-arabinose:D-galactose in the WSP was 37:49, 34:37, and 27:29, when extracted using RTW, HW, and HTPW, respectively. These results indicate that water was a suitable extraction solvent for preparation of the arabinogalactan component of whole purslane. A higher yield and total carbohydrate content was obtained by using Viscozyme L instead of Pectinex 5XL during extraction of the WSP, which indicates that enzymatic treatment of purslane may be an effective method to control the Mw of polysaccharides. Finally, it was confirmed that Viscozyme L is a suitable enzyme for the hydrolysis and separation of polysaccharides obtained from purslane.

• International Journal of Air-Conditioning and Refrigeration
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• v.13 no.1
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• pp.51-60
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• 2005

This paper reviews the studies on the pressure drop and the heat transfer in microchannels. Although a lot of studies about the single-phase flow have been done until now, conflicting results are occasionally reported about flow transition from laminar flow to turbulent flow, friction factor, and Nusselt number. Some studies reported the early flow transition due to relatively greater wall effect like surface roughness, but the other studies showed that the flow transition occurred at the Reynolds number of about 2300 and the early flow transition might be due to less accurate measurement of the channel geometry. Also, there have been arguments whether the conventional relation based upon continuum theory can be applied to the fluid flow and the heat transfer in microchannels without modification or not. The studies about the two-phase flow in microchannels have been mostly about investigating the flow pattern and the pressure drop in rectangular channels using two-component, two-phase flow like air/water mixture. Some studies proposed correlations to predict two-phase flow pressure drop in microchannels. They were mostly based on Lockhart-Martinelli model with modification on C-coefficient, which was dependent on channel geometry, Reynolds number, surface tension, and so on. Others investigated the characteristics of flow boiling heat transfer in microchannels with respect to test parameters such as mass flux, heat flux, system pressure, and so on. The existing studies have not been fully satisfactory in providing consistent results about the pressure drop and the heat transfer in microchannels. Therefore, more in-depth studies should be done for understanding the fundamentals of the transport phenomena in the microchannels and giving the basic guidelines to design the micro devices.

• Journal of the Korean earth science society
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• v.22 no.4
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• pp.292-300
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• 2001

By using two methods we obtained plane solutions for 5 groups of earthquakes including 13 events, which occurred in the central region of South Korea after December 1997. The first method is the composite fault plane solution by P wave polarity, and the second the solution by amplitude ratio (SV/P, SH/P, SV/SH) and P and S wave polarities. The two method results show similar results. The strike of fault is in the direction of NNE-SSW and WNW-ESE with the movement of strike-slip or strike-slip including thrust component. The compressional axis of the stress field dominantly trends ENE-WSW or NE-SW. The results are almost consistent with the other main events occurred in and around the Korean Peninsula.

• Composites Research
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• v.33 no.4
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• pp.185-190
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• 2020

Titanium is widely used as an implant material due to its excellent biocompatibility, but has a problem due to high cost and high Young's modulus compared to bone. Magnesium alloy is attracting attention as a material to replace it. Magnesium alloy, like titanium, has excellent biocompatibility and has a Young's modulus similar to that of bone. However, there are corrosion resistance problems due to corrosion, and various surface treatment methods are being studied to solve them. In this study, the ceramic coating layer was grown on the surface of the AZ31 magnesium alloy in an electrolytic solution containing EDTA, and the properties of the formed coating were analyzed through SEM and XRD to analyze the microstructure and shape, and measured the micro hardness of the coating layer. Corrosion properties in the body were evaluated through a corrosion test in SBF solution, a component similar to blood plasma.