• Food Science and Biotechnology
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• v.17 no.5
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• pp.971-975
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• 2008

This study was to examine the potential disinfection efficiencies of 10 compounds by determining their antimicrobial capacity and ichthyotoxicity. Antimicrobial effects against Vibrio sp., Edwadsiella tarda, Streptococcus sp., and Staphylococcus sp. were tested using 10 different disinfectants; hydrogen peroxide, sodium hypochlorite, chlorine dioxide, povidon iodine, formaldehyde, glutaraldehyde, quaternary ammonium compounds (QACs), didecyl dimethyl ammonium chloride (DDAC), ortho-dichlorobenzen, and copper sulfate. Chlorine dioxide ($ClO_2$) containing 5% $ClO_2$ and copper sulfate had no effects on bactericidal activity, while the other disinfectants resulted in 99.99% bactericidal activity against 4 strains of fish pathogenic bacteria. The ichthyotoxicity of the 10 disinfectants was investigated using 3 kinds of fish species; flounder (Paralichthys olivaceus), rockfish (Sebastes pachycephalus), and black sea bream (Acanthopagrus schlegelii). Median lethal concentration ($LC_{50}$) values of the 10 disinfectants were estimated to determine toxicity ranges of the doses within 24 hr. Among test disinfectant solutions, hydrogen peroxide showed the highest $LC_50$ in flounder (201.3), rockfish (269.7), and black sea bream (139.3 ppm). DDAC revealed the lowest $LC_{50}$ in flounder (2.1), rockfish (1.0), and black sea bream (1.5 ppm). These results suggest that DDAC, quaternary ammonium compounds, glutaraldehyde, and sodium hypochlorite are effective disinfectants for fish and bacterial species examined in this study.

• Applied Chemistry for Engineering
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• v.9 no.2
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• pp.273-277
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• 1998

The synthesis of hydroxy-terminated poly(propylene carbonate)(HTPPC) was performed by the reaction of propylene carbonate(PC) with alcohol initiator using metal alkoxides, crown ethers and quaternary onium salts as catalysts. The effects of catalyst structure, types and concentration of alcohol, and solvent were investigated. Among the alkoxide catalysts tested, the ones with higher Lewis acidity and with more nucleophilic alkoxide anion showed higher catalytic activity. Mixed catalysts of metal alkoxied and crown ether showed higher conversion of PC than metal alkoxide alone. Quaternary onium salts of bulky cation exhibited higher catalytic activity. High polar solvent showed higher yield of HTPPC and the yield increased with the decrease of [PC]/[Initiator] ratio.

• The Korean Journal of Quaternary Research
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• v.21 no.1
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• pp.37-45
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• 2007

Skull base height increases significantly with better nutrition and health conditions. With coordinate caliper or by subtraction, skull base height is easily measured. To examine nutrition and health condition of MIA(missing in action) during the Korean War and people who lived during the 17-18 centry of the Late Chosun. This study is focused on the change of skull base height through time as seen in comparing 83 MIA cranium and 12 17-18 centry cranium of Korea with 219 modern American middle class adult cranium(Terry Collection and forensic skeleton). To sum up, nutritional condition of MIA is not significantly changed, as seen in comparing with nutritional condition of 17-18 century people.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• v.21 no.4
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• pp.297-305
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• 2018

Purpose: There is a lack of scholarly reports on pediatric emergency department (PED) exposure to hyperbilirubinemia. We aimed to describe the epidemiology of hyperbilirubinemia in patients presenting to a PED over a three-year period. Methods: This was a retrospective cohort study, completed at an urban quaternary academic PED. Patients were included if they presented to the PED from 2010 to 2012, were 0 to 18 years in age, and had an elevated serum bilirubin for age. A chart review was completed to determine the incidence of hyperbilirubinemia, etiology, diagnostic work up and prognosis. The data set was stratified into four age ranges. Results: We identified 1,534 visits where a patient was found to have hyperbilirubinemia (0.8% of all visits). In 47.7% of patients hyperbilirubinemia was determined to have arisen from an identifiable pathologic etiology (0.38% of all visits). First-time diagnosis of pathologic hyperbilirubinemia occurred in 14% of hyperbilirubinemia visits (0.11% of all visits). There were varying etiologies of hyperbilirubinemia across age groups but a male predominance in all (55.0%). 15 patients went on to have a liver transplant and 20 patients died. First-time pathologic hyperbilirubinemia patients had a mortality rate of 0.95% for their initial hospitalization. Conclusion: Hyperbilirubinemia was not a common presentation to the PED and a minority of cases were pathologic in etiology. The etiologies of hyperbilirubinemia varied across each of our study age groups. A new discovery of pathologic hyperbilirubinemia and progression to liver transplant or death during the initial presentation was extremely rare.

• The Korean Journal of Quaternary Research
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• v.20 no.2
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• pp.30-50
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• 2006

The long-lived radionuclide, $^{10}Be$, is produced by cosmic-ray effects in the atmosphere of the earth as well as its surface and that of other planetary surfaces and atmospheres. Accelerator mass spectrometry (AMS) was developed in late 1970s, which made $^{10}Be$ terrestrial measurements more feasible. Since then, many research applications of $^{10}Be$ for both terrestrial and extraterrestrial applications have been developed, which parallel the wide range of radiocarbon ($^{14}C$) research applications. This paper summarizes production mechanisms of $^{10}Be$ both in the atmosphere and on the surface of terrestrial and extraterrestrial environments and also provides numerous $^{10}Be$ research applications in the fields of geomorphology, oceanography, archaeology, glaciology, cosmochemistry, climatology, and planetary science. We also review some $^{10}Be$ AMS research applications.

• The Korean Journal of Quaternary Research
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• v.23 no.1
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• pp.1-24
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• 2009

Paleosol layers lying on top of the terrace in Jeongdongjin area appear to have been deposited under generally well-drained condition with periodic waterlogging. From a 4.5m-long profile observed, a total of 6 stratigraphic units were identified. Grain-size analysis indicates the dominance of silty and clay materials with some portions with high sand content. Major mineralogical elements are quartz, feldspar, mica and chlorite. Geo-chemical composition shows little change throughout the stratigraphy with some fluctuation in chemical weathering index. Marked increase in magnetic susceptibility is recognizable where stratigraphic unit changes. Soil- wedge layer is developed around 50cm below the surface with concentration of grains of AT tephra (c. 25,000 BP). An OSL date of c. 110,000 BP was obtained from a sand layer lying below the paleosol.

• Korean Journal of Microbiology
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• v.53 no.4
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• pp.297-303
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• 2017

Leucine-responsive regulatory protein (LRP) is a regulatory protein of molecular weight 18.8 kDa and is widely known to regulate many metabolic and functional activities of operons in Escherichia coli. The gene for Lrp from Escherichia coli in pQE system of 6 ${\times}$ His-tagging was expressed and $^3H$-labeled protein, as well as the wild type Lrp, was purified. The crosslink experiments were performed to analyze the quaternary structure of Lrp at high of $5{\mu}M$ and at low concentrations below $0.3{\mu}M$ with cross linkers, such as glutaraldehyde, 1, 2, 3, 4-diepoxy-butane (DEB), and ethylene glycol bis (succinimidyl succinate) (EGS). In the experiments, we found that the Lrp protein can be formed higher conformation states of tetramer, hexamer, octamer, as well as dimeric state when incubated with the above cross linkers.

• The Korean Journal of Quaternary Research
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• v.14 no.2
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• pp.87-99
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• 2000

May-June precipitation (253 years : A.D. 1746∼1998) of Yungdong region (coastal area of East-central Korea) was reconstructed using two tree-ring chronologies of Pinus densiflora sampled from Daeseung Fall area in Sorak Mountains. Dry periods were 1765∼1800 (longest dry period), 1835∼1845, 1890∼1910, 1920∼1940 and 1980∼1995, and wet ones 1810∼1830, 1850∼1890 and 1950∼1970. In long-term variation, late 18th century was dry. The 19th century May-June (250㎜) was wetter than the 20th century (231㎜) and the former indicated higher variability than the latter. Major wet/dry periodicities in May-June precipitation series reconstructed were 3 years in short term and 60∼80 years in long term. The present reconstructed data agreed to the ancient rain gauge 'Chukwooki' data (1777∼1907) of Seoul (central-west Korea) in low frequency variations except early 1800s.

• International Journal of Concrete Structures and Materials
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• v.10 no.sup3
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• pp.97-108
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• 2016

When the energy performance of concrete is substantially higher than that of normal type concrete, such concrete is regarded as energy efficient concrete (WBSCSD 2009). An experimental study was conducted to investigate mechanical properties of energy efficient concrete with binary, ternary and quaternary admixture at different curing ages. Slump test for workability and air content test were performed on fresh concretes. Compressive strength, splitting tensile strength were made on hardened concrete specimens. The mechanical properties of concrete were compared with predicted values by ACI 363R-84 Code, NZS 3101-95 Code, CSA A23.3-94 Code, CEB-FIP Model, EN 1991, EC 2-02, AIJ Code, JSCE Code, and KCI Code. The use of silica fume increased the compressive strengths, splitting tensile strengths, modulus of elasticities and Poisson's ratios. On the other hand, the compressive strength and splitting tensile strength decreased with increasing fly ash.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.19 no.4
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• pp.3-19
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• 2009

This paper proposes efficient scalar multiplication algorithms based on Montgomery ladder method. The proposed algorithm represents the scalar as ternary or quaternary and applies new composite formulas utilizing only x coordinate on affine coordinate system in order to improve performance. Furthermore, side-channel atomicity mechanism is applied on the proposed composite formulas to prevent simple power analysis. The proposed methods saves at least 26% of running time with the reduced number of storage compared with existing algorithms such as window-based methods and comb-based methods.