• Journal of Photoscience
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• 제12권1호
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• pp.11-15
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• 2005

The mechanism of interaction of two drugs viz., amoxicillin and cloxacillin with bovine serum albumin has been investigated using fluorescence absorption and circular dichroism spectroscopy. The quenching mechanism of fluorescence of bovine serum albumin by amoxicillin and cloxacillin was discussed. The binding sites number n and apparent binding constant Kwere measured by fluorescence quenching method. The thermodynamic parameters obtained from data at different temperatures were calculated. The distance r between donor (bovine serum albumin) and acceptor (amoxicillin and cloxacillin) was obtained according to Forster theory of non-radiative energy transfer. The effect of common ions on binding constant was also investigated. The results of synchronous fluorescence spectra, UV-vis absorption spectra and circular dichroism of BSA in presence of amoxicillin and cloxacillin show that the conformation of bovine serum albumin changed

• 한국의학물리학회지:의학물리
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• 제9권4호
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• pp.259-266
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• 1998

코발트-60 근접조사선원을 대체할 Ir-l92 선원주변의 2차원적 선량분포를 얻기 위하여, 조사선량률과, 조직감쇠계수를 구하였다. 조직감쇠계수는 선원에서 20 cm 지점까지 실험식을 구하였다. ？보기 방사능은 조사선량상수를 사용하여 결정하였으며, 2.5mm 직경에 두께 2.5 mm 의 선원은 조직선량을 정하기 위해 선원을 4401 개로 분할하여 선원 자체의 흡수효과와 ？슐벽의 차폐 효과와 조직감쇠계수를 적용하였다. 조직감쇠계수는 4차식을 사용하여 1% 오차범위내에서 실험값을 얻을 수 있었으며, Meisberger 상수는 선원에서 많이 떨어질수록 오차가 커서, 10 cm 위치서 7%, 20 cm 에서 33%의 오차를 발견할 수 있었으나, 겉보기방사능과 선원모양 및 크기가 달라 다른 결과를 가져올 수 있다고 본다. 발표된 Ir-192 선원의 에너지스펙트럼을 이용한 선량률상수는 절삭에너지 10 keV인 경우 4.69 R$cm^2$/mCi-hr을 얻었으며 Air Kerma는 0.973 을 구하였다. 이 실험에서 고안 선원의 분할선원에 의한 선원자체흡수와 ？슐벽에 의한 감쇠는 실선원의 54.6%가 겉보기방사능으로 나타남을 알 수 있었으며, 선량계획에 이용하기 위해 단위 ？보기 방사능에 대한 2차원적 선량표를 준비함으로써 기하학적선량과 선량 비등방성을 쉽게 이용할 수 있도록 하였다.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1999년도 학회창립 10주년 기념 1999년도 가을 학술발표회 논문집
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• pp.593-596
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• 1999

Steel fibers are added to concrete to improve energy absorption, impact resistance and apparent ductility, and to provide crack resistance and crack control. This study is to investigate the toughness index and post-crack equivalent tensile strength of steel fiber reinforced concrete properties on the load-deflection behaviors of the steel fiber reinforced concrete beam model specimens.

• Journal of Pharmaceutical Investigation
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• 제14권3호
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• pp.136-143
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• 1984

Inclusion complex formation of fenbufen with ${\beta}-cyclodextrin$ in water and in solid state was comfirmed by solubility method, ultra violet absorption, circular dichroism and infra-red spectroscopies, differential thermal analysis, and X-ray diffractometry. A solid complex of fenbufen with ${\beta}-cyclodextrin$ in 1 : 1 molar ratio was prepared by the freeze-drying method, its dissolution characteristics in water and its analgesic and antiinflammatory effect in mouse or rat were examined. The apparent release of fenbufen from the inclusion complex was significantly improved, hut no significant difference in its analgesic and antiinflammatory effect was found.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2000년도 가을 학술발표회논문집(I)
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• pp.655-660
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• 2000

This study was performed to verify the properties of concrete used recycled aggregate(0, 30%, 50%). Also, to improve the brittle fracture, energy absorption and apparent ductility of concrete, we added polypropylene fibers(0, 0.1, 0.2, 0.5, 1.0% by volume of concrete). As the experimental results, adding 30% recycled aggregates and 0.5% polypropylene fibers to concrete mixes enhances the properties of both compressive strength and toughness.

• 한국식품조리과학회지
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• 제32권5호
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• pp.531-540
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• 2016

Purpose: To improve the cooking quality of brown rice, newly inbred soft rice cultivars were investigated. Methods: The physicochemical properties of brown rice flour and water absorption patterns and cooking characteristics of brown rice grain were compared to Ilmi white and brown rice. Results: General composition and total dietary fiber contents of five rices were significantly different with higher ash, protein, and total dietary fiber contents in soft brown rice than white rice. The hardness of raw rice grain was higher in Ilmi brown rice than in soft brown rice. The water absorption increased rapidly in 30 min of white rice and in 4-6 h of brown rices. The apparent amylose content of soft brown rice was lower than that of Ilmi rice. The initial pasting temperature and all viscosities were significantly different, but the trend was not similar. The textural properties of hardness and roughness were higher, but adhesiveness, cohesiveness, and stickiness were lower in Ilmi brown rice than white and soft brown rices. In sensory preference test, not only textural properties, hardness, adhesiveness, cohesiveness, stickiness, and roughness, but also color, glossiness, and roasted flavor were higher in soft brown rices. Especially soft brown rice B showed the best cooking quality among all rices. Conclusion: The results of the study suggested that soft brown rice is developed for cooking with high nutritional and functional quality.

• BMB Reports
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• 제29권4호
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• pp.335-342
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• 1996

Porcine liver cysteinesulfinic acid decarboxylase was purified approximately 460-fold by means of ammonium sulfate fractionation and sequential column chromatographic separation with Sephadex G-100, DEAE-cellulose and hydroxylapatite. The enzyme has a flat pH profile with maximum activity occurring between pH 6.0 and 7.6. Pyridoxal 5'-phosphate must be present in all buffers used for purification procedures in order to stabilize the enzyme. Addition of sulfhydryl reagents such as 2-mercaptoethanol are also necessary to maintain maximum enzyme activity throughout purification. The absorption spectrum shows that cysteinesulfinic acid decarboxylase is a pyridoxal 5' -phosphate-containing protein. The major absorption is at 280 nm with two smaller absorption regions, one at 425 nm which is ascribed to a Schiffs base between pyridoxal phosphate and protein, and another at 325 nm which is thought to be due to the interaction of 2-mercaptoethanol with the Schiffs base. A number of divalent cations tested did not affect enzyme activity with the exception of mercury, copper, and zinc which are inhibitory. The partially purified enzyme has an apparent $K_m$ of 0.94 mM for cysteinesulfinate. Cysteic acid is a competitive inhibitor of the enzyme with a $K_i$ of 1.32 mM. The molecular weight of the enzyme was estimated to be about 79,600 by using Sephadex G-200 column chromatography.

• 분석과학
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• 제11권3호
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• pp.202-205
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• 1998

X선 흡수 미세구조 분석 기술을 이용하여 Ni-Zn 도금 강판에서의 Ni 주위 국부구조를 연구하였다. 실험적으로 측정한 X선 흡수 미세구조 스펙트럼과 이론적인 스펙트럼을 비교 분석함으로서 Ni-Zn 원자간 거리와 Debye-Waller factor를 결정하였는데 이때 측정 온도의 범위는 80K로부터 300K까지이었다. 이 측정 온도 범위내에서는 Ni-Zn 원자간 거리의 온도에 따른 변화는 매우 작았으며 원자간 거리의 평균값은 $2.557{\AA}$이었다. 그리고 이러한 Ni-Zn 원자간 거리의 값을 순수한 Zn 금속 재료의 가장 가까운 이웃 원자간 거리의 값과 비교하여 볼 때 Ni-Zn 전기 도금층의 Ni 원자 주위에 약간의 contraction이 있는 것을 알 수 있었다. 한편, Debye-Waller factor는 온도에 따라 0.005~0.011 정도의 값을 가지며 비교적 큰 온도 의존도를 가지는 것으로 나타났다.

• Preventive Nutrition and Food Science
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• 제12권4호
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• pp.217-221
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• 2007

Within the elderly population, the use of calcium supplements and the intake of calcium from food are on the rise in order to maintain health. Calcium is absorbed as an ion in vivo, leading to speculation that absorption efficiency is affected by the solubility of the calcium consumed. In our study, the bioavailability of two types of calcium supplements with different solubilities was evaluated. Experimental animals were fed water-soluble or insoluble calcium supplements for 6 weeks. We found that blood alkali phosphatase activity, osteocalcin content, and urine crosslinks values were not different between the groups. Similarly, the degree of apparent calcium absorption between the two calcium supplements was not significantly different. The bone mineral density and bone mineral content of the femur and the tibia increased in the group that consumed insoluble calcium compared with those of the water-soluble calcium supplemented group. However, when considering body weight, the bone mineral density value for all areas, including the spine, was significantly higher in the group that consumed the water-soluble calcium supplement.

• Advances in concrete construction
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• 제11권1호
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• pp.73-80
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• 2021

Rice Husk Ash (RHA) geopolymer paste activated by sodium aluminate were characterized by X-ray diffractogram (XRD), scanning electron microscope (SEM), energy dispersion X-Ray analysis (EDAX)and fourier transform infrared spectroscopy (FTIR). Five series of RHA geopolymer specimens were prepared by varying the Si/Al ratio as 1.5, 2.0, 2.5, 3.0 and 3.5. The paper focuses on the correlation of microstructure with hardened state parameters like bulk density, apparent porosity, sorptivity, water absorption and compressive strength. XRD analysis peaks indicates quartz, cristobalite and gibbsite for raw RHA and new peaks corresponding to Zeolite A in geopolymer specimens. In general, SEM micrographs show interconnected pores and loosely packed geopolymer matrix except for specimens made with Si/Al of 2.0 which exhibited comparatively better matrix. Incorporation of Al from sodium aluminate were confirmed with the stretching and bending vibration of Si-O-Si and O-Si-O observations from the FTIR analysis of geopolymer specimen. The dense microstructure of SA2.0 correlate into better performance in terms of 28 days maximum compressive strength of 16.96 MPa and minimum for porosity, absorption and sorptivity among the specimens. However, due to the higher water demand to make the paste workable, the value of porosity, absorption and sorptivity were reportedly higher as compared with other geopolymer systems. Correlation regression equations were proposed to validate the interrelation between physical parameters and mechanical strength. RHA geopolymer shows comparatively lower compressive strength as compared to Fly ash geopolymer.