• 한국식품저장유통학회지
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• 제15권1호
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• pp.9-14
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• 2008

본 연구는 장기저장이 가능한 김치제조를 위해 사용된 20kGy의 선량으로 감마선 조사된 김치와 동결건조된 김치의 미생물학적,조직학적 및 관능적 품질특성을 비교하였다. 김치의 총균수는 감마선조사 후 검출한계 이하로 나타났으나 동결 건조된 김치는 비조사 대조구에 비해 1 log 수준의 미생물 감소를 나타내었다. 감마선조사 김치의 경도는 동결건조 후 재수화된 김치에 비해 유의적으로 높았다. 전자현미경을 통한 김치 조직 관찰 결과 동결건조 후 복원된 김치에서만 표피세포의 미세구조가 심하게 변형된 것이 관찰되었다. 또한 관능평가 결과 색, 조직감, 맛 기호도는 감마선 조사된 김치가 동결건조 후 재수화 된 김치보다 유의적으로 높았다.

• 한국식품영양과학회지
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• 제34권6호
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• pp.797-804
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• 2005

폐자원을 이용한 기능성 신소재 개발 연구를 위해 감귤 음료 가공 중 생성되는 부산물인 감귤 과피를 추출·정제하여 얻어진 감귤정유의 생리활성 효과를 검증하고 감마선에 의한 영향도 확인하였다 감귤 정유의 limonene의 함량은 $88.3\pm1.30\%$로 나타났으며 감마선 조사한 시료에서도 limonene의 함량은 차이가 없는 것으로 나타났다. 감귤 정유의 전자공여능은 약 70$\%$로 나타났으며 돈육에 감귤 정유 첨가 시 지질산패가 억제 되는것을 확인할 수 있었다. 감글 정유에 대한 항균 활성은 paper disc diffusion test 결과를 바탕으로 농도에 따른 생육저해효과를 측정한 결과 yeast는 250 ppm에서, bacteria는 $2,500\~5,000$ ppm에서, mold는 $5,000\~10,000$ ppm에서 생육이 억제되어, yeast에 대한 항균활성이 가장 우수한 것으로 나타났다. MTT assay를 이용한 세포독성실험 결과 대부분의 암세포에서 약 $90\%$ 이상의 억제율을 보였으며 Ames test를 이용한 복귀돌연변이 시험에서는 $200\mu g/plate$이 하일 때 감귤 정유의 돌연변이 원성이 나타나지 않는 것으로 확인되었다. 전체적인 시험 결과 감마선 조사에 의한 생리활성 변화의 차이는 없는 것으로 나타났다. 따라서 식품 및 공중보건제품 소재로서 가공부산물인 귤 정유는 경제적이면서 효과적으로 사용될 수 있으리라 기대된다.

• Restorative Dentistry and Endodontics
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• 제19권1호
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• pp.1-26
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• 1994

The purpose of this study was to investigate the dissolution components during corrosion of amalgams and to identify surface corrosion products in the modified Fusayama artificial saliva. Four type of amalgam alloys were used: low copper lathe cut amalgam alloy (Cavex 68), low copper spherical amalgam alloy (Caulk Spherical Alloy), high copper admixed amalgam alloy (Dispersalloy) and high copper single composition amalgam alloy (Tytin). Each amalgam alloy and Hg were triturated according to the manufacturer's direction by means of mechanical amalgamator (Capmaster, S.S.White), and then the triturated mass was inserted into the cylindrical metal mold which was 10mm in diameter and 2.0mm in height and condensed with compression of 150kg/$cm^2$ using oil pressor. The specimens were removed from the mold and stored at room temperature for 7 days and cleansed with distiled water for 30 minutes in an ultrasonic cleaner. The specimens were immersed in the modified Fusayama artificial saliva for the periods of 1 month, 3 months and 6 months. The amounts of Hg, Cu, Sn and Zn dissolved from each amalgam specimen immersed in the artificial saliva for the periods of 1 month, 3 months and 6 months were measured using Inductivity Coupled Plasma Atomic Emission Spectrometry (ICPQ-1000, Shimadzu, Japan) and amount of Ag dissolved from amalgam specimen was measured using Atomic Absorption Spectrophotometry (Atomic Absorption/Flame emission spectrophotometer M-670, Shimadzu, Japan). A surface corrosion products of specimens were analysed using Electron Spectroscopy Chemical Analyser (ESCA PHI-558, PERKIN ELMER, U.S.A.). The secondary image and back scattered image of corroded surface of specimens was observed under the SEM, and the corroded surface of specimens was analysed with the EDX. The following results were obtained. 1. The dissolution amount of Cu was the most in high copper admixed amalgam(Dispersalloy) and the least in high copper single composition amalgam(Tytin). 2. Sn and Zn were dissolved during all the experiment periods, and dissolution amounts were decreased as the time elapsed. 3. Initial surface corrosion products were ZnO and SnO. 4. Corrosion of ${\gamma}$ and ${\gamma}_2$ phase in low copper amalgams was observed and Ag-Cu eutectic alloy phase was corroded in low copper spherical amalgam(Caulk Sperical Alloy). 5. Corrosion of ${\gamma}$ and $\eta$' phase in high copper amalgams was observed and Ag-Cu eutectic alloy phase was corroded in high copper admixed amalgam(Dispersalloy). 6. Sn-Cl was produced in the subsurface of low copper amalgams and high copper admixed amalgam.

• 대한한방내과학회지
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• 제30권1호
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• pp.212-227
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• 2009

Objective : Membranous nephropathy (MN) is one of the most commonest forms of glomerular disease in man and the most frequent cause of the adult idiopathic nephrotic syndrome. Some investigators recommend no treatment, while others propose aggressive therapy, including prednisolone plus an immunosupressant such as chlorambucil or cyclophosphamide. But a more effective way to treat MN is not defined yet. This study was to evaluate the effects of Patriniae Radix extract (PRE) on the MN induced by cBSA in mice. Methods : Mice were divided into 4 groups. The first group (normal) was injected with saline. The second group (control) was treated with cBSA (10 mg/kg i.p) only. The third group, named PRE-2S0, was treated with cBSA (10 mg/kg i.p) and PRE (250 mg/kg, p.o). The fourth group, PRE-500, was treated with cBSA (10mg/kg i.p) and PRE (500mg/kg, p.o). After cBSA and PRE treatment for 4 weeks, we measured change of body weight, 24hrs proteinuria, serum albumin, total cholesterol, triglyceride, BUN, creatinine, IgG, IgA, IgM, $TNF-\alpha$, $IL-1\beta$, and $IFN-\gamma$ levels and the mRNA expression of $IFN-\gamma$, IL-6, and IL-10. The morphologic changes of renal glomeruli were also observed with a light microscope and an electron microscope. Results : The levels of 24 hrs proteinuria and serum triglyceride. BUN. IgG. $TNF-\alpha$, and $IL-1\beta$ significantly decreased in both PRE groups, while the level of serum albumin significantly increased in both PRE groups. The mRNA expression of IL-10 in splenocytes considerably increased in both PRE groups. The mRNA expression of $IFN-\gamma$ and IL-6 in splenocytes considerably increased in both PRE group. In histological findings of kidney tissue, thickening of GBM decreased in both PRE groups. Conclusions : The present study suggests that PRE is effective when treating mice with MN induced by cBSA. More clinical data and studies are to be done for efficient application.

• 공업화학
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• 제25권3호
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• pp.274-280
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• 2014

비용매 유도 상전이(nonsolvent induced phase separation, NIPS) 방법을 이용하여 PSf (polysulfone) 중공사 분리막을 제조하였다. PSf/DMAc (N,N-dimethylacetamide)로 이루어진 고분자 용액에 조용매로 GBL (${\gamma}$-butyrolactone)을 첨가하였으며, 물을 응고용액으로 이용하여 중공사 분리막을 제조하였다. 제조된 분리막은 전자주사현미경을 이용하여 그 구조를 분석하였으며 그 결과 GBL의 농도가 증가함에 따라 밀집 구조의 분리활성층과 스폰지 형상의 지지층으로 구성된 이중구조 형태의 비대칭 다공성의 구조를 나타내었다. 또한, 조용매 GBL은 고분자용액의 용해도 상수를 변화시켜 열역학적 상분리 촉진 역할을 할 수 있음을 알 수 있었다. 고분자용액 내의 조용매 GBL의 존재 유무와 GBL의 농도, 첨가제의 농도 그리고 내부응고제의 종류에 따라 중공사 분리막의 구조뿐만 아니라 순수투과도 및 분리특성에도 매우 큰 영향을 미치는 것을 확인하였다. 내부응고제로 EG보다 PEG를 사용하였을 경우 $0.05{\mu}m$ PSL (polystyrene latex) bead를 이용하여 배제 특성을 측정한 결과 5% 정도로 소폭 감소한 반면 순수투과플럭스는 최대 130배 이상 증가하는 효과를 나타내었다.

• Preventive Nutrition and Food Science
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• 제7권3호
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• pp.273-277
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• 2002

Physiological properties of root and stolen of Gamcho (Licorice, Glycyrrhiza uralensis Fischer) were compared following irradiation at 20 kGy. The root and stolen of Gamcho were extracted with 70 % ethanol, irradiated and stoved in a 4"C refrigerator. Irradiation induced color changes, electron donating ability (EDA), and tyro-sinase inhibition effect (TIE) were investigated. The color of the non-irradiated stolen extract was darker than the non-irradiated root extract (p<0.05), but irradiation eliminated color differences between stolen and root extracts. Generally, irradiation did not affect EDA and TIE of either of the extracts. However, EDA and TIE were higher in stolen extract than in root extract, when the higher dilution factor was considered. These results indicate that the stolen of Gamcho, which is mostly wasted, is a valuable source of phytochemicals with greater EDA and TIE activities than Gamcho root.root.

• Corrosion Science and Technology
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• 제14권2호
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• pp.64-75
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• 2015

Single $TiO_2$ coating prepared by sol-gel process usually experiences cracks in coating layer. In order to prevent cracks, an inorganic-organic hybrid $TiO_2-SiO_2$ coating was synthesized by combining precursors with an organic functional group. Five different coatings with various ratios of (1:8, 1:4, 1:1, 1:0.25 and 1:0.125) titanium alkoxide (TBOT, Tetrabutylorthotitanate) to organo-alkoxysilane (MAPTS, ${\gamma}$-Methacryloxy propyltrimethoxysilane) on carbon steel substrate were made by sol-gel dip coating. The prepared coatings were analyzed to study the coating properties (surface crack, thickness, composition) by scanning electron microscope (SEM), focused ion beam (FIB), and Fourier transform infrared spectroscopy (FT-IR). Potentiodynamic polarization tests and electrochemical impedance spectroscopy (EIS) were also performed to evaluate the corrosion characteristics of the coatings. Crack free $TiO_2-SiO_2$ hybrid coatings were prepared with the optimization of the ratio of TBOT to MAPTS. The corrosion rates were significantly decreased in the coatings for the optimized precursor ratio without cracks.

• Advances in materials Research
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• 제2권1호
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• pp.15-36
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• 2013

Incorporation of polar functional moieties into polyethylene (PE) film has been achieved by graft copolymerization of polar monomers such as methacrylic acid (MAAc) and acrylamide (AAm) on to PE film, preirradiated with ${\gamma}$-rays from $^{60}Co$ source, using benzoyl peroxide (BPO) as initiator in aqueous medium. Percentage of grafting of MAAc and AAm was determined as a function of irradiation dose, monomer and initiator concentration, temperature, reaction time and amount of water. Maximum percentage of grafting of MAAc (1453%) and AAm (21.28%) was obtained at [MAAc] = $235.3{\times}10^{-2}$ mol/L, [AAm] = $23.4{\times}10^{-2}$ mol/L, [BPO] = $5.5{\times}10^{-2}$ mol/L and $16.5{\times}10^{-2}$ mol/L at $80^{\circ}C$, $90^{\circ}C$ in 180 min and 90 min respectively. The grafted PE films were characterized by FTIR, Thermogravimetric analysis (TGA) Scanning Electron Micrography (SEM) and X-ray diffraction methods. Some selective properties of grafted films such as swelling behavior, ion and metal uptake have been carried out. The biodegradation studies of the grafted PE films have also been investigated. The grafted films developed superior swelling behavior with maximum swelling (480%) in water as compared to pristine PE (13.55%), better thermal stability and ion and metal uptake studies showed promising results that can be effectively used for desalination of brackish water and separation of metals from the industrial effluents.

• Preventive Nutrition and Food Science
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• 제3권3호
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• pp.295-301
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• 1998

Potential applications of irradiation technology inpostharvest handling of agricultural products have been documented over the past five decades. The biological effects of ionizing radiation on food were demonstrated to have the potential both of reducing the storage losses by controlling spoilage microoraganisms, insects, to have the potential both of reducing the storge losses by controlling spoiliage microorganisms, insects, sprouting and ripening, and of improving the hygienic quality of raw and processed products. Food irradiation is recognized as a physical and cold process using gamma-rays from radioisotope sources and electron-beam from the accelerator. As one of the technologies or techniques for preserving and improving the safety of food, irradiated technology has been approved in some 40 countries for more than 200 individeual items of foods and of these about 30 countries including Korea are commerically utilizing this technology. Although limited quantities of irradiated foods are available in the market now, the proper uses of this renewed technology will offer great possibilities not only for increasing the availability of postharvest agricultural products, thereby contributing to price stabilization in the off-season, but also for reducing reliance on chemicals used for sanitary and quarantine requirements. This paper deals with biological actions of ionizing radiation and its potential applications in the agri-food industry from the international point of view.

• 천문학회보
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• 제40권2호
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• pp.30.1-30.1
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• 2015

Radio relics are diffuse radio sources found in the outskirts of galaxy clusters and they are thought to trace synchrotron-emitting relativistic electrons accelerated at shocks. We explore a diffusive shock acceleration (DSA) model for radio relics in which a spherical shock with the parameters relevant for the Sausage radio relic in cluster CIZA J2242.8+5301 impinges on a magnetized cloud containing fossil relativistic electrons. This model is expected to explain some observed characteristics of giant radio relics such as the relative rareness, uniform surface brightness along the length of thin arc-like radio structure, and spectral curvature in the integrated radio spectrum. We find that the observed surface brightness profile of the Sausage relic can be explained reasonably well by shocks with speed $u_s{\sim}3{\times}10^3km/s$ and sonic Mach number $M_s{\sim}3$. These shocks also produce curved radio spectra that steepen gradually over $(0.1-10){\nu}_{br}$ with a break frequency ${\nu}_{br}{\sim}1GHz$, if the duration of electron acceleration is ~60-80 Myr. However, the abrupt increase in the spectral index above ~1.5 GHz observed in the Sausage relic seems to indicate that additional physical processes, other than radiative losses, operate for electrons with the Lorentz factor, ${\gamma}_e$ > $10^4$.