• Mycobiology
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• 제39권1호
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• pp.12-19
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• 2011

Cellular damage caused by reactive oxygen species has been implicated in several diseases, thus establishing a significant role for antioxidants in maintaining human health. Acetone, methanol, and hot water extracts of Pleurotus citrinopileatus were evaluated for their antioxidant activities against ${\beta}$-carotene-linoleic acid and 1,1-diphenyl-2-picrylhydrazyl (DPPH) radicals, reducing power, ferrous ion-chelating abilities, and xanthine oxidase inhibitory activities. In addition, the tyrosinase inhibitory effects and phenolic compound contents of the extracts were also analyzed. Methanol and acetone extracts of P. citrinopileatus showed stronger inhibition of ${\beta}$-carotene-linoleic acid compared to the hot water extract. Methanol extract (8 mg/mL) showed a significantly high reducing power of 2.92 compared to the other extracts. The hot water extract was more effective than the acetone and methanole extracts for scavenging DPPH radicals. The strongest chelating effect (92.72%) was obtained with 1.0 mg/mL of acetone extract. High performance liquid chromatography analysis detected eight phenolic compounds, including gallic acid, protocatechuic acid, chlorogenic acid, ferulic acid, naringenin, hesperetin, formononetin, and biochanin-A, in an acetonitrile and hydrochloric acid (5 : 1) solvent extract. Xanthine oxidase and tyrosinase inhibitory activities of the acetone, methanol, and hot water extracts increased with increasing concentration. This study suggests that fruiting bodies of P. citrinopileatus can potentially be used as a readily accessible source of natural antioxidants.

• 한국지하수토양환경학회지:지하수토양환경
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• 제18권1호
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• pp.26-35
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• 2013

Outbreak of animal infectious diseases such as foot-and-mouth disease, avian influenza are becoming prevalent worldwide. For prevent the further infection, tremendous numbers of the infected or culled stocks are buried around farm. This burial method can generate a wide range of detrimental components such as leachate, nutrient, salt, and pathogenic bacteria, consequently. In this study, for the stabilization of livestock carcasses leachate, advanced oxidation processes utilizing the Fenton reaction was investigated in lab-scale experiments for the treatment for $COD_{Cr}$ of livestock carcass leachate. $COD_{Cr}$ reduction by the Fenton oxidation was investigated response surface methodology using the Box-Begnken methods were applied to the experimental results. A central composite design was used to investigate the effects of the independent variables of pH ($x_1$), dosage of $FeCl_2{\cdot}4H_2O$ ($x_2$) and dosage of $H_2O_2$ ($x_3$) on the dependent variables $COD_{Cr}$ concentration ($y_1$). A 1 M NaOH and $H_2SO_4$ was using for pH control, $FeCl_2{\cdot}4H_2O$ was used as iron catalyst and NaOH was used for Fenton reaction. The optimal conditions for Fenton oxidation process were determined: pH, dosage of $FeCl_2{\cdot}4H_2O$ and dosage of $H_2O_2$ were 3, 0.6 g (0.0151 M) and 7 mL(0.259 M), respectively. Statistical results showed the order of significance of the independent variables to be pH > initial concentration of ferrous ion > initial concentration of hydrogen peroxide.

• Corrosion Science and Technology
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• 제14권6호
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• pp.288-295
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• 2015

The present work addresses crevice and galvanic corrosion processes occurring at the cylinder head gasket/cylinder head interface and cylinder head gasket/cylinder liner interface of four-stroke medium-speed diesel engines for marine applications. The contact between these systems and the marine environment can promote formation of demanding corrosion conditions, therefore influencing the lifetime of the engine components. The electrochemical behavior of various metals and alloys used as head gasket materials (both ferrous alloys and copper alloys) was investigated. The efficacy of corrosion inhibitors was determined by comparing electrochemical behavior with and without inhibitors. In particular, crevice corrosion has been investigated by electrochemical tests using an experimental set-up developed starting from the requirements of the ASTM G-192-08, with adaptation of the test to the conditions peculiar to this application. In addition to the crevice corrosion resistance, the possible problems of galvanic coupling, as well as corrosive reactivity, were evaluated using electrochemical tests, such as potentiodynamic measurements. It was possible to quantify, in several cases, the corrosion resistance of the various coupled materials, and in particular the resistance to crevice corrosion, providing a basis for the selection of materials for this specific application.

• Journal of Welding and Joining
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• 제17권6호
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• pp.84-89
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• 1999

Most of ferrous b.c.c weld materials may experience martensitic transformation during rapid cooling after welding. It is well known that volume expansion due to the phase transformation could influence on the relaxation of welding residual stress. To apply this effect practically, it is a prerequisite to establish a numerical model which is able to estimate the effect of phase transformation on residual stress relaxation quantitatively. For this purpose, the analysis is carried out in two regions. i.e., heating and cooling, because the variation of material properties following a phase transformation in cooling is different in comparison with the case in heating, even at the same temperature. The variation of material properties following phase transformation is considered by the adjustment of specific heat and thermal expansion coefficient, and the distribution of residual stress in analysis is compared with that of experiment by previous study. consequently, in this study, simplified numerical procedures considering phase transformation, which based on a commercial finite element package was established through comparing with the experimental data of residual stress distribution by other researcher. To consider the phase transformation effect on residual stress relaxation, the transition of mechanical and thermal property such as thermal expansion coefficient and specific heat capacity was found by try and error method in this analysis.

• 한국환경보건학회지
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• 제38권6호
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• pp.568-574
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• 2012

Objectives: The purpose of this experiment is to understand the phosphorus removal ratio effects of iron plates per unit of surface area through the iron electrolysis system, which consists of an anoxic basin, aerobic basin, and iron precipitation apparatus. Methods: Iron electrolysis, which uses an iron precipitation reactor in anoxic and oxic basins, consisted of iron plates with total areas of 400 $cm^2$, 300 $cm^2$ and 200 $cm^2$ respectively. The FNR process was operated with a hydraulic retention time and a sludge retention time of 12 hours and three days, respectively. Wastewater used in the experiments was prepared by dissolving $KH_2PO_4$ in influent water. Results: The iron plates 400 $cm^2$ (16.6 $mA/cm^2$), 300 $cm^2$ (13.3 $mA/cm^2$) and 200 $cm^2$ (7.3 $mA/cm^2$) in surface area in the phosphorus reactor had respective phosphorus of 2.4 mg/l, 2.7 mg/l and 3.2 mg/l in the effluent and phosphorus removal respective efficiencies of 90.3%, 89.1% and 87.1%. The effluent in the reactor, where the iron plate was not used, had relatively very low phosphorus removal efficiency showing phosphorus concentration of 15.3 mg/l and a phosphorus removal efficiency about 38.3%. Phosphorus removal per ferrous was 0.472 mgP/mgFe in the iron electrolysis system where the surface area of iron was low. Phosphorus pollution load per active surface area and the phosphorus removal efficiency had an interrelation of RE = -0.27LS + 89.0 (r = 0.85). Conclusion: With larger iron plate surface area, the elution of iron concentration and phosphorus removal efficiency was higher. The removal efficiency of phosphorus has decreased by increasing the initial phosphate concentration in the iron electrodes. This shows a tendency of decreasing phosphorus removal efficiency because of decreasing of iron deposition as the phosphorus pollution load per active surface area increases.

• Journal of Applied Biological Chemistry
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• 제61권2호
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• pp.109-117
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• 2018

최근까지도, 현대사회의 암 발생률은 급격하게 증가하고 있다. 인체 내부에서 내재적 또는 외재적인 요인에 의해 DNA 손상이 발생되고, 세포는 DNA 손상에 대한 방어기작을 통해 스스로를 방어한다. 또한, 비정상적인 DNA 생성 및 결손된 DNA 가닥의 복원은 노화, 암, 염증 등 다양한 질병으로부터 기인한다. 많은 연구자는 이러한 DNA 손상을 억제하기 위하여 적절한 소재 탐색에 많은 관심을 두고 있으며, 특히 합성화합물의 부작용이 알려지면서, 천연물을 기반으로 한 암 예방적 소재에 대한 연구가 많이 이루어지고 있다. 토복령은 백합과(Liliacese)에 속하는 청미래덩굴(Smilax china L.)의 근경이며, 전통적으로 해독과 종기 등의 치료제로 사용되어왔다. 하지만 토복령의 DNA 손상에 대한 억제 효과에 대한 연구는 미흡하다. 본 논문에서는 토복령의 항산화 효과 및 DNA 손상에 대한 억제 효과를 확인하고, 식물이 포함하는 phenolic 화합물의 활성과 연관 관계를 확인하고자 하였다. 항산화 효과를 확인하기 위해, DPPH 라디칼 및 ABTS 라디칼에 대한 소거 활성을 확인하였다. 토복령 추출물은 DPPH 및 ABTS 라디칼을 효과적으로 제거하였으며, 높은 환원력을 나타냈다. HPLC 분석을 통해 phenolic 화합물을 정량 및 동정하였으며, 항산화 효과와 phenolic 화합물의 연관 관계를 확인하였다. 또한, $OH^-$ 라디칼 및 $Fe^{2+}$으로 유발된 plasmid DNA 손상에 대한 방어 효과를 확인하였다. 세포 수준에서, DNA 손상에 대한 저해 효과는 산화적 스트레스로 유발된 NIH 3T3 세포의 ${\gamma]$-H2AX 및 p53 단백질 발현 저해 활성을 확인하였다. 또한, H2AX 및 p53 mRNA 수준의 저해 활성을 확인하였다. 결론적으로, 토복령 추출물의 phenolic 화합물의 항산화 효과 및 DNA 손상에 대한 억제 효과를 확인하였다.

• 한국미생물·생명공학회지
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• 제4권3호
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• pp.91-97
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• 1976

고온성 방선균으로부터 내열성 $\alpha$-Amylase의 생산과 그 이용 가능성을 검토하기 위하여 토양시료로부터 $\alpha$-Amylase 생산능력이 극히 우수한 구주를 분리하여 분리균의 몇가지 균학적 성질내지는 효소생산을 위한 배양조건을 조사하여 전보에 발표하였으며 본보에서는 공시방선균이 생산하는 $\alpha$-Amylase의 효소학적 일반성질을 검토하여 다음과 같은 결과를 얻었다. 1) 본효소의 최적활성 pH는 6.5이었으며 최적변성온도는 55$^{\circ}C$~$65^{\circ}C$이었다. 2) 본효소의 안정 pH범위는 7.0~8.0에 위치 하였으며 3) 활성에 대한 금속 ion의 영향은 $Ca^{＋＋}$ 및 $Na^{＋＋}$ ion에 의하여 촉진되었으나 중금속 ion인 Fe$^{＋＋}$ Cu$^{＋＋}$ ion등은 현저히 조해함을 보였으며 열안정성에 대한 금속 ion의 효과는 $Ca^{＋＋}$ ion에 의해 증가했다. 4) 본 순소의 Km value는 2.17$\times$$10^{-4}$g per $m\ell$이었으며 5) Activation energy는 12,000$\pm$580 ㎈ per mole 이었다.

• 한국광물학회지
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• 제24권2호
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• pp.91-99
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• 2011

울산시에 삼동면에 위치한 천부 관정 지하수들 중 일부는 탁도가 음용수 기준을 크게 초과한다. 광물학적 분석결과, 극미립 부유입자는 지름 $0.5\;{\mu}m$ 이하의 구상 페리하이드라이트(ferrihydrite), 페리하이드라이트로 교대된 나선형 철산화 박테리아 섬유, 그리고 이들의 집합체였다. 페리하이드라이트는 거의 비정질로서 2개의 전자회절환만 관찰되었고, Si와 P가 함유되어 있었다. 나선형 철산화 박테리아는 지하수의 용존 $Fe^{2+}$의 산화뿐만 아니라 페리하이드라이트의 침전 장소를 제공하였다. 주변의 보통 지하수와 비교하여 pH와 Eh가 낮고, Ca 함량과 알칼리도가 높아서 한국 탄산약수의 일반적 수질 특정과 잘 부합되어, 용존철이 풍부한 심부 기원 탄산수의 유입이 추정된다. 따라서 높은 페리하이드라이트 탁도는 pH, Eh, 알칼리도 등의 수질인자와 함께 천부 지하수 관정을 이용한 심부 기원 탄산지하수 추적의 지시자로 활용될 가능성이 있다.

• 대한지역사회영양학회지
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• 제6권5호
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• pp.726-733
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• 2001

This study was designed to investigate the effect of iron supplementation on the iron nutritional status and anemia of high school girls in Korea. One hundred thirty-five female students residing in Ulian metropolitan city in Korea diagnosed as having anemia or iron deficiency participated in this study. One or two tablets of iron medicine(80-160 mg Fe as ferrous sulfate/day) were administered to all participants for 3 months. Subjects were evaluated with a questionaire, measurement of hematological indices before and after iron supplementation. The average height and weight of respondents were 161.62 $\pm$ 4.68 cm and 53.87 $\pm$ 6.10 kg, respectively. Daily intakes of energy were 1597.8 $\pm$ 302.35 kcal(76.0% RDA). Iron intakes were 13.72 $\pm$ 4.17 mg (76.3% of RDA) and calcium intakes were 580.74 $\pm$ 177.21(72.5% of RDA) before iron supp]ementation. At baseline, 63% of all participants had depleted store(serum ferritin 12 ug/ml and/or transferrin saturation(TS) < 14%). After iron supplementation, this proportion declined to 19.3%. 55.6% of subjects had 12 ug/m1 of basal ferritin concentration before iron supplementation, and this proportion declined to 16.3% after iron supplementation. The basal hemoglobin(Hb) concentrations were 12.13 $\pm$ 1.01 g/dl and they increased to 12.79 $\pm$ 0.81 g/dl, which showed significant difference artier iron supplementation(p < 0.001). The basal ferritin and TS(%) were 13.24 $\pm$ 11.66 ng/ml, 18.42 $\pm$ 10.12% and they significantly increased to 32.95 $\pm$ 21.14 ng/ml, 33.53 $\pm$ 16.64%, respectively(p < 0.001). The basal total iron binding protein(TIBC) were 467.81 $\pm$ 97.24 ug/dl and they significantly decreased to 325.05 $\pm$ 48.89 ug/dl(p < 0.001) after iron supplementation. The number of tablets administered was positively correlated with serum iron(t = 0.553, p < 0.01), serum ferritin(t = 0.557, p < 0.01), TS(%)(t = 0.588, p < 0.01) and negatively correlated with TIBC(t= -0.409, p <0.01). The anemia symptoms such as ‘Shortening of breath when going upstairs(p < 0.01)’, ‘Tired out easily(p < 0.01)’, ‘Feeling blue(p < 0.001)’, ‘Decreased ability to concentrate(p < 0.01)’, and ‘Poor memory(p < 0.001)’improved significantly after iron supplementation. In this study, daily iron supplementations were efficacious in improving the iron status and anemic symptoms of female high school students. Regular check-ups and nutrition education for adolescents are necessary because of their vulnerability to iron deficiency. Further studies are needed to determine the minimum effective dose of iron and to examine the adverse effect of long-term iron supplementation.

• Asian-Australasian Journal of Animal Sciences
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• 제18권10호
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• pp.1485-1491
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• 2005

This experiment was conducted to investigate the effects of iron from an amino acid complex (Availa-$Fe^{\circledR}$) on the iron status of neonatal and suckling piglets. A total of 24 gestating sows (Landrace${\times}$Large White) were randomly allocated to three dietary treatments. The control diet contained 80 mg $kg^{-1}$ Fe from ferrous sulfate heptahydrate ($FeSO_4$.$7H_2O$), while the two experimental diets were supplemented with an additional 120 mg $kg^{-1}$ Fe from Availa-$Fe^{(R)}$ or $FeSO_4$.$7H_2O$, respectively. The lactating sows remained the same iron treatments as gestating sows, while neonatal piglets of 24 litters born from the above sows were allotted to another three treatments. Piglets from the sows of the control treatment were fed basal diet with no supplemental Fe as control treatment, but were injected with 100 mg Fe as Fe dextran at birth. Piglets from the sows of Availa-$Fe^{(R)}$ or $FeSO_4$.$7H_2O$ treatments were supplemented with 120 mg $kg^{-1}$ iron from Availa-$Fe^{(R)}$ or $FeSO_4$.$7H_2O$, respectively. The total born alive and weaned, and the average piglets weight at birth and at weaning were not significantly affected by the sow' dietary treatments (p>0.05). Iron from Availa-$Fe^{(R)}$ did not demonstrate a statistically significant improvement in hemoglobin concentration, hematocrit and plasma iron of sows on day 90 and 105 of pregnancy and the milk iron of sows during lactation (p>0.05). Neonatal piglets in the Availa-$Fe^{(R)}$ treatment had a significantly higher hemoglobin concentration (p<0.05) and higher hematocrit and plasma iron (p>0.05) than those in the other two treatments, respectively. The hemoglobin of suckling piglets in the Availa-$Fe^{(R)}$ treatment was higher than that of piglets in $FeSO_4$.$7H_2O$ treatment on day 28 (p<0.05). The total iron binding capacity of piglets in Availa-$Fe^{(R)}$ treatment was lower than that of piglets in the control and $FeSO_4$.$7H_2O$ treatment on day 14 (p<0.05), but there was not a statistically significant difference among three treatments on day 28 (p>0.05). However, the hemoglobin and hematocrit of suckling piglets injected with Fe were higher than those of piglets in the other two treatments (p<0.05). This study indicated that the addition of 120 mg $kg^{-1}$ iron from amino acid complex into the diets improved iron status of neonatal and nursing piglets more effectively than the addition of 120 mg $kg^{-1}$ iron from $FeSO_4$.$7H_2O$, however, this improvement of the organic Fe was not sufficient to replace the Fe injection for prevention of iron-deficiency anemia.