• The Korean Journal of Malacology
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• v.27 no.3
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• pp.247-252
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• 2011

The effect of ${\gamma}$-ray irradiation on the color of nucleus and cultured pearls was investigated. After ($^{60}Co$) ${\gamma}$-ray irradiation on the pearl nucleus, its color was altered from brownish to blackish brown or gray depending on irradiation dose. It was clearly found that the all samples are composed of aragonite. ESR spectra were based on the measurement of the paramagnetic species $CO_2$-radicals by the interaction with the ${\gamma}$-ray irradiation in $Mn^{2+}$ containing $CaCO_3$. In this study, we investigated optimal detection method of ${\gamma}$-ray irradiation to establish destructive or non-destructive test for pearl nucleus.

• Journal of the East Asian Society of Dietary Life
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• v.12 no.4
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• pp.318-325
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• 2002

Cooking characteristics of coated rice with water homogenate of citrus fruit peels (1% for rice) were investigated. The color of the coated rice both before and after cooking was dark yellow. The total content of carotenoids, hesperidin and naringin were 10.74, 2173.12 and 1468.40 mg% for citrus fruit peels, 0.46, 108.65 and 73.35 % for its water homogenate, 0.12, 21.73 and 14.62 mg% for coated rin, and 0.05, 8.67 and 5.87 mg% fur cooked coated rice, respectively. Citrus fruits peel contained 94.22 mg% of asparagine, 24.88 mg% of methionine, 19.64 mg% of alanine, and 15.37 mg% of ${\gamma}$-aminoisobutyric acid as the majority free amino acids, accounting for 70% of the total free amino acids present. Total free amino acid content of the cooked coated rice increased by 15% compared to those of cooked uncoated rice. The majority of minerals in the citrus fruit peels were K and Ca, accounting for 56% of total minerals present. The mineral content of cooked coated rice was generally higher than that of the cooked uncoated rice. The cooked coated rice showed comparable hardness, gumminess and brittleness, but higher cohesiveness and springiness than the cooked uncoated rice. There were no differences in sweet and bitter taste between the cooked uncoated and coated rice. However, the cooked coated rice showed higher sensory scores fur color acceptability, savory taste and overall acceptability than the cooked uncoated rice.

• Journal of Life Science
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• v.20 no.9
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• pp.1385-1393
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• 2010

Three mold strains, Aspergillus oryzae (AOFAG), Aspergillus kawachii (AKFAG), and Monascus purpureus (MPFAG) were used for fermentation of Angelica gigas Nakai powder. The contents of polyphenolic compounds, flavonoids, minerals, decursin and decursinol angelate and the activities of DPPH (${\alpha},{\alpha}'$-diphenyl-$\beta$-picrylhydrazyl) free radical scavenging, reducing power, and tyrosinase were measured. The highest contents of phenolic compound and flavonoid were NFAG at 2.78% and MPFAG at 1.18%, respectively. Major minerals were K, Mg, Fe, Na and Ca. Decursin and decursinol angelate were the major ingredients of Angelica gigas according to HPLC analysis. Decursin area was higher in all fermented Angelica gigas than in NFAG. The activities of free radical scavenging and tyrosinase were stronger in all fermented Angelica gigas than NFAG. However, the Fe/Cu reducing powers were stronger in NFAG than all fermented Angelica gigas. Overall, these results may provide the basic data needed to understand the biological activities and chemical characteristics of Angelica gigas fermented by mold for the development of functional foods.

• The Journal of Advanced Prosthodontics
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• v.3 no.2
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• pp.57-62
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• 2011

MATERIALS AND METHODS. Ceramics have a long history in fixed prosthodontics for achieving optimal esthetics and various materials have been used to improve ceramic core strength. However, there is a lack of information on how color is affected by fabrication procedure. The purpose of this study was to evaluate the effects of various dentin ceramic thicknesses and repeated firings on the color of zirconium oxide all-ceramic system (LavaTM) fabricated using CAD/CAM technology. MATERIALS AND METHODS. Thirty disc-shaped cores, 12 mm in diameter with a 1 mm thickness were fabricated from zirconium oxide based all ceramic systems ($Lava^{TM}$, 3M ESPE, St Paul, MN, USA) and divided into three groups (n = 10) according to veneering with dentin ceramic thicknesses: as 0.5, 1, or 1.5 mm. Repeated firings (3, 5, 7, or 9) were performed, and the color of the specimens was compared with the color after the initial firing. Color differences among ceramic specimens were measured using a spectrophotometer (VITA Easyshade, VITA Zahnfabrik, Bad $S{\ddot{a}}ckingen$, Germany) and data were expressed in CIELAB system coordinates. A repeated measures ANOVA and Bonferroni post hoc test were used to analyze the data (n = 10, ${\alpha}=.05$). RESULTS. $L^{\ast}a^{\ast}b^{\ast}$ values of the ceramic systems were affected by the number of firings (3, 5, 7, or 9 firings) (P<.001) and ceramic thickness (0.5, 1, or 1.5 mm) (P<.001). Significant interactions were present in $L^{\ast}a^{\ast}b^{\ast}$ values between the number of firings and ceramic thickness (P<.001). An increase in number of firings resulted in significant increase in $L^{\ast}$ values for both 0.5 mm and 1.5 mm thicknesses (P<.01, P=.013); however it decreased for 1 mm thickness (P<.01). The $a^{\ast}$ values increased for 1 mm and 1.5 mm thicknesses (P<.01), while it decreased for 0.5 mm specimens. The $b^{\ast}$ values increased significantly for all thicknesses (P<.01, P=.022). As the dentin ceramic thickness increased, significant reductions in $L^{\ast}$ values (P<.01) were recorded. There were significant increases in both $a^{\ast}$ and $b^{\ast}$ values (P<.01) as the dentin ceramic thickness increased. CONCLUSION. The number of firings and dentin ceramic thickness have a definite effect on the final color of all ceramic system tested. The mean ${\Delta}E$ value increased as the dentin ceramic thicknesses increased for zirconium-oxide based all ceramic specimens tested. However, the mean ${\Delta}E$ values were less than 3.7${\Delta}E$ units which is rated as a match in the oral environment.

• Journal of Environmental Science International
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• v.25 no.11
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• pp.1541-1554
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• 2016

To understand the characteristics of vanadium leaching from soils formed by the weathering of basalts, paleo soil at Gosan, Jeju Island, Korea, and several present-day soils from neighboring areas were collected. Leaching experiments were carried out by two approaches: 1) batch experiments under various geochemical conditions (redox potential (Eh) and pH) and 2) continuous leaching experiments under conditions similar to those of natural environments. From the batch experiments, leached vanadium concentrations were highest under alkaline (NaOH) conditions, with a maximum value of $2,870{\mu}g/L$, and were meaningful (maximum value, $114{\mu}g/L$) under oxidizing ($H_2O_2$) conditions, whereas concentrations under other conditions (acidic-HCl, $neutral-NaHCO_3$, and $reducing-Na_2S_2O_3$) were negligible. This indicated that the geochemical conditions, in which soil-water reactions occurred to form groundwater with high vanadium concentrations, were under alkaline-oxidizing conditions. From the continuous leaching experiments, the pH and leached vanadium concentrations of the solution were in the ranges of 5.45~5.58 and $6{\sim}9{\mu}g/L$, respectively, under $CO_2$ supersaturation conditions for the first 15 days, whereas values under $O_2$ aeration conditions after the next 15 days increased to 8.48~8.62 and $9.7{\sim}12.2{\mu}g/L$, respectively. Vanadium concentrations from the latter continuous leaching experiments were similar to the average concentration of groundwater in Jeju Island ($11.2{\mu}g/L$). Furthermore leached vanadium concentrations in continuous leaching experiments were highly correlated with pH and Al, Cr, Fe, Mn and Zn concentrations. The results of this study showed that 1) alkaline-oxidizing conditions of water-rock (soil) interactions were essential to form vanadium-rich groundwater and 2) volcanic soils can be a potential source of vanadium in Jeju Island groundwater.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.29 no.4
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• pp.245-248
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• 2003

The retraction of anterior teeth could be performed more easier by inducing of skeletal anchorage system rather than by conventional method on orthodontic treatment. But, we wonder how effective the system draws well without anchorage loss and draws anterior teeth aside posteriorly, and if the system can reduce the time, in comparison with the anchorage of posterior teeth. For that reason we have studied on the subject of patients, who were required the maximum anchorage on orthodontic treatment and the cases without crowding. The subjects of the experimental group are 35 areas of 20 people who were inserted miniscrews after Mx or Mn 1st premolar extracted. Also, the subjects of the control group are 81 areas of 45 people who were not inserted miniscrews. Compared the anchorage loss of experimental group with control one, we could get the result that the anchorage loss of experimental group is $1.034{\pm}0.891mm$ and control group is $2.790{\pm}1.882mm$(P<0.01). Compared the space closing time of experimental group with control one, we could get the result that the space closing time of experimental group is $369.40{\pm}110.81$days and control group is $406.56{\pm}231.63$days. But the result of comparing space closing time has no significance in statistics. We recognized that the experimental group is more faster than the control group in the canine retraction velocity from the result ; the speed of a experimental group has as much as $0.60{\pm}0.23mm/30days$ while the speed of a control group has $0.44{\pm}0.35mm/30days$(P<0.05). So, we could convince that orthodontic miniscrew is used effectively in the cases required the maximum anchorage.

• Journal of Life Science
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• v.30 no.6
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• pp.522-531
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• 2020

The aim of this study was to establish the optimal medium composition for enhancing L(+)-lactic acid (LLA) production using response surface methodology (RSM). Lactobacillus paracasei SRCM201474 was selected as the LLA producer by productivity analysis from nine candidates isolated from kimchi and identified by 16S rRNA gene sequencing. Plackett-Burman design was used to assess the effect of eleven media components on LLA production, including carbon (glucose, sucrose, molasses), nitrogen (yeast extract, peptone, tryptone, beef extract), and mineral (NaCl, K₂HPO₄, MgSO₄, MnSO₄) materials. Glucose, sucrose, molasses, and peptone were subsequently chosen as promising media for further optimization studies, and a hybrid design experiment was used to establish their optimal concentrations as glucose 15.48 g/l, sucrose 16.73 g/l, molasses 39.09 g/l, and peptone 34.91 g/l. The coefficient of determination of the equation derived from RSM regression for LLA production was mathematically reliable at 0.9969. At optimum parameters, 33.38 g/l of maximum LLA increased by 193% when compared with MRS broth as unoptimized medium (17.66 g/l). Our statistical model was confirmed by subsequent validation experiments. Increasing the performance of LLA-producing microorganisms and establishing an effective LLA fermentation process can be of particular benefit for bioplastic technologies and industrial applications.

• Proceedings of the KWS Conference
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• 2010.05a
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• pp.27-27
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• 2010

청정에너지원의 수요가 증가함에 따라 에너지원의 공급로의 역할을 하는 강관의 수요가 증가하고 있다. 소재가공 기술의 발전과 함께 경량의 고장력 강재의 적용은 공급로의 역할을 하는 강관의 비용절감 및 자원의 효율적 이용 측면에서 지속적으로 연구 개발을 이어왔다. 이러한 추세에 따라 구조용 또는 라인파이프용 강관에서도 고장력 강재의 적용과 함께 고인성 그리고 용접성의 향상을 위한 다양한 라인파이프용 강재의 개발과 이의 적용이 그간 활발히 진행되어왔다. 용도상 반드시 필요한 특성인 고장력, 고인성, 용접성 등 외에도 다양한 강재의 사용에 따른 제조공정상 즉 용접공정에서 발생될 수 있는 용접부의 기계적 특성 변화에 대한 특성 연구 및 기술 연구가 계속 되어왔다. 주로 강관을 생산하는데 쓰이는 ERW (Electric Resistance Welding) 공정에서도 이러한 문제점을 해결하기 위해 많은 연구가 진행되고 있다. ERW는 높은 생산성과 낮은 제조비용의 장점을 가지고 있으나 용접 후 용접부의 기계적 특성 감소로 인한 단점이 있다. 때문에 기계적 특성향상을 위해 최적의 용접조건에 대해 연구해야 할 필요가 있다. 본 연구에서는 4가지 합금강관의 ERW 용접시 용접 입열량의 변화와 용접부의 후열처리를 통한 미세조직의 변화와 기계적 특성에 대해서 고찰하였다. 4강종 시편의 미세조직을 OM, SEM을 통한 분석 이후 인장시험 및 경도시험 등을 통해 기계적 특성을 평가하였다. 대부분의 시편에서 입열량의 증가에 따라 Ferrite 분율이 증가하였고 용접중앙부의 Ferrite 양이 용접경계부 보다 많았다. Ferrite 집중부의 분포가 극명하게 관찰되었던 DP780 (적정) 강종과 미세하게나마 Ferrite 집중부가 존재하였던 K55 (과소, 과대) 강종에서 나란히 경도 하락 현상이 관찰되었다. 이는 강종마다 고유의 Ceq, 합금 중 Mn 농도, 입열량 등에 의한 복합적인 이유 때문으로 판단된다. 탄소가 0.3~0.4 wt% 함유된 중탄소강인 S45C, K55의 경우 용접중앙부와 용접경계부의 페라이트 분율 차이가 큰 것을 알 수 있었다. 이는 용접시 열에 의한 탈탄현상으로 인해 나타나는 현상으로 판단된다.

• Journal of the Korean Society of Food Science and Nutrition
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• v.37 no.11
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• pp.1422-1426
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• 2008

The purpose of this study was to test characteristics between normal and autistic children via comparison of nutrient intakes, hair mineral, blood free radical, and serotonin contents. A total of 50 children aged 3-9 were divided into two main groups of normal control children (n=22) and autistic children (n=28) tested by child psychiatrist. The nutrient intakes by 24-hour recall method were no significantly different between the two groups. The concentrations of toxic mineral, such as cadmium (Cd) and lead (Pb) in hair of autistic children were significantly higher, while concentration of antioxidant mineral (Cu, Zn, Fe) was lower than that of normal children. The autistic children had significantly higher concentrations of blood free radical than that of normal children. No significant difference was observed in serotonin concentration between the two groups. Our results suggest a possible role of increased toxic mineral and free radical, both of which may be relevant to the pathophysiology of autism in children with developmental delay.

• Journal of Microbiology and Biotechnology
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• v.20 no.3
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• pp.518-524
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• 2010

A mannanase gene (man26B) was obtained from a sea bacterium, Paenibacillus sp. BME-14, through the constructed genomic library and inverse PCR. The gene of man26B had an open reading frame of 1,428 bp that encoded a peptide of 475- amino acid residues with a calculated molecular mass of 53 kDa. Man26B possessed two domains, a carbohydrate binding module (CBM) belonging to family 6 and a family 26 catalytic domain (CD) of glycosyl hydrolases, which showed the highest homology to Cel44C of P. polymyxa (60% identity). The optimum pH and temperature for enzymatic activity of Man26B were 4.5 and $60^{\circ}C$, respectively. The activity of Man26B was not affected by $Mg^{2+}$ and $Co^{2+}$, but was inhibited by $Hg^{2+},\;Ca^{2+},\;Cu^{2+},\;Mn^{2+},\;K^+,\;Na^+$, and $\beta$-mercaptoethanol, and slightly enhanced by $Pb^{2+}$ and $Zn^{2+}$. EDTA did not affect the activity of Man26B, which indicates that it does not require divalent ions to function. Man26B showed a high specific activity for LBG and konjac glucomannan, with $K_m,\;V_{max}$, and $k_{cat}$ values of 3.80 mg/ml, 91.70 ${\mu}mol$/min/mg protein, and 77.08/s, respectively, being observed when LBG was the substrate. Furthermore, deletion of the CBM6 domain increased the enzyme stability while enabling it to retain 80% and 60% of its initial activity after treatment at $80^{\circ}C$ and $90^{\circ}C$ for 30 min, respectively. This finding will be useful in industrial applications of Man26B, because of the harsh circumstances associated with such processes.