• Journal of Periodontal and Implant Science
• /
• v.31 no.4
• /
• pp.651-659
• /
• 2001

후박추출물은 치주병인균에는 항균효과가 있고, 치은섬유아세포에는 세포독성이 적은 것으로 알려져 있으며 홍아씨 추출물은 골아세포를 활성화시키는 효과가 있어 골조직재생에 효과가 있는 것으로 알려져 있다. 이 실험의 목적은 비글견에 인위적으로 치주염을 유도하고 후박추출물과 홍화씨추출물의 혼합물을 투여함으로써, 이 두 가지 혼합물이 치주염 진행에 예방효과가 잇는지, 또, 치료효과가 있는지 알아보는 것이다. 후박과 홍화씨를 구입하여 에탄올에서 추출하여 정제하고 진공상태에서 건조시켜 농축하였다. 후박추출물과 홍화씨 추출물을 1:5의 질량비로 혼합하고 250㎎씩 캡슐에 넣었다. 비글견의 상하악 소구치와 하악 제1대구치를 8주 동안 철사와 견사로 결찰하여 치주염을 유발하였다. 8주 후에, 실험군 비글견에게는 미리 후박추출물과 홍화씨추출물 혼합물을 매 12시간마다 하루에 1,500㎎ 씩 12주 동안 투약하였다. 대조군 비글견에는 투약을 하지 않았다. 투약을 시작한 후에 치은지수, 부착수준을 매 4주마다 측정하였다. 매 4주마다 치주낭에서 페이퍼포인트를 이용하여 혐기성세균과 호기성세균을 채취, 배양하여 각각의 집락 수를 세었다. 그 결과 실험군의 치은지수는 8주, 12주에서 대조군보다 유의하게 낮았고(p<0.05)), 임상적으로도 상당한 치은염의 개선을 보였다. 실험군의 혐기성세균 집락수는 감소하여 4, 8, 및 12주에서 대조군에 비해 유의하게 낮았고(p<0.001), 호기성 세균 집락수는 4, 8, 및 12주에서 대조군에 비해 유의하게 낮았다.(p<0.05)이 실험 결과, 후박 추출물과 홍화씨 추출물 혼합물이 치주질환의 예방 및 치료에 이용되어질 수 있을 것으로 생각된다.

• Polymer(Korea)
• /
• v.31 no.5
• /
• pp.447-453
• /
• 2007

In this study, we fabricated recrystallized PLGA (rPLGA) particles using the vacuum drying method. In order to investigate an applicability of the rPLGA particles for controlled release system of 5-fluorouracil (5-FU) loaded PLGA wafer, we prepared three different wafers using; 1) untreated PLGA (uPLGA), 2) rPLGA, and 3) uPLGA and rPLGA (4 : 1, 1 : 1 or 1 : 4). The rPLGA particles were characterized using NMR, IR and GPC to compare with uPLGA particles. The surface and cross section morphology of the prepared wafers were observed by the scanning electron microscope. The release profile of the 5-FU loaded wafer was measured by HPLC. The 5-FU/rPLGA wafer released the incorporated 5-FU in a sustained manner with low initial burst compared to 5-FU/uPLGA. These results showed that the ratio of pure PLGA/recrystallized PLGA can affect the release behaviors.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.24 no.3
• /
• pp.404-408
• /
• 1995

The effect of processing conditions on the changes in the contents of dietary fiber fractions and its physical properteis of Godulbaegi(Korean lettuce, Ixeris sonchifolia H.) was determined during preparation and fementation for kimchi. Water holding capacity(WHC) and oil adsorption capacity(OAC) were also checked on the subject of freeze dried powder from different stages of the kimchi processing. Neutral detergent fiber(NDF) content in young samples(leaf and root) decreased with prolonged soaking and fermentation period. Every young samples had a higher level in NDF than in ripe samples. Noticeable decrease in acid detergent fiber(ADF) without a change in ripe roots was showed after fermentation($4^{\circ}C$, 60 days). The water holding capacity of freeze dried young plants ranged from 5.78ml/g for roots to 6.31ml/g for leaves. Soaking and fermentation resulted in decreasing WHC and about 50% of WHC(raw leaves) was lowered after kimchi fermentation($4^{\circ}C$, 40 days). OAC of all samples were lower than WHC in same samples significantly and those were also decreased after soaking and fermentations as WHC.

• Korean Chemical Engineering Research
• /
• v.49 no.6
• /
• pp.804-809
• /
• 2011

Tubular $Ba_{0.5}Sr_{0.5}Co_{0.8}Fe_{0.2}O_{3-${\delta}$}$ membranes were prepared by extrusion. TGA results of green body membrane after extrusion showed three successive weight losses due to decomposition of organic additives and carbonate. Drying shrinkage rate of tubular $Ba_{0.5}Sr_{0.5}Co_{0.8}Fe_{0.2}O_{3-${\delta}$}$ membranes was no change after 68 h and higher in the membrane with large outer diameter. XRD and SEM results showed the sintered membranes were the single phase structure and dense. The stoichiometric molar ratio agreed well with composition ratio calculated by EDS results for $Ba_{0.5}Sr_{0.5}Co_{0.8}Fe_{0.2}O_{3-${\delta}$}$ membrane. Radial crushing strength of tubular $Ba_{0.5}Sr_{0.5}Co_{0.8}Fe_{0.2}O_{3-${\delta}$}$ membrane with 0.95 mm thickness was 5.7 kgf/$mm^2$ and the oxygen permeation rate of same membrane was 146.85 mL/min ($Jo_2$=2.33 mL/$min{\cdot}cm^2$) at $950^{\circ}C$. Therefore, it was known that use of vacuum pump was more effective than that of sweep gas to obtain higher oxygen permeation flux.

• Journal of the Computational Structural Engineering Institute of Korea
• /
• v.30 no.6
• /
• pp.531-539
• /
• 2017

This paper deals with the development of bonded joints for fibre reinforced plastic (FRP) hull structures using moulding-in concept. Focus is placed on bonded in-plane connections between two adjacent panels that could form the boundaries of hull structural module. Traditional construction in FRP hull structures requires the construction of a mould, usually from steel or aluminium. In this construction the FRP materials are laid in the mould, and resin is saturated, and then the structural member is cured. This is expensive since it involves the fabrication of metal hull mould for every different hull type, which is sacrificed after the production of the FRP ship. One way of encouraging greater use of FRP in ship construction is to investigate the possible construction of FRP hull structures in a similar manner to metallic ships, that is in terms of blocks or modules. Such a manner of construction would eliminate the need for expensive hull moulds permitting greater flexibility in the construction of FRP ships. The main issue then would be the design and construction of adequate bonded connections between adjacent panels. To fulfill this object, the simplified and automated way of manufacturing joint edge shapes for bonded joints is developed, and their structural assessment is performed in both experimentally and numerically.

• Journal of the Korean Magnetics Society
• /
• v.9 no.2
• /
• pp.78-84
• /
• 1999

$(Ni, Zn)Fe_2O_4$ powders were prepared through self-propagating high temperature synthesis reaction and the effects of initial zinc oxide powder size and oxygen pressure on the magnetic properties of the final combustion products were studied. The ferrite powders were combustion synthesized with iron, iron oxide, nickel oxide, and zinc oxide powders under various oxygen pressures of 0.5~10 atmosphere after blended in n-hexane solution for 5 minutes with a spex mill, followed by dried at 120 $^{\circ}C$ in vacuum for 24 hours. The maximum combustion temperature and propagating rate were about 1250 $^{\circ}C$ and 9.8 mm/sec under the tap density, which were decreased with decreasing ZnO size and oxygen pressure. The final product had porous microstructure with spinel peaks in X-ray spectra. As the ZnO particle size in the reactant powders and oxygen pressure during the combustion reaction increase, coercive force, maximum magnetization, residual magnetization, squareness ratio were changed from 1324 Oe, 43.88 emu/g, 1.27 emu/g, 0.00034 emu/gOe, 37.8$^{\circ}C$ to 11.83 Oe, 68.87 emu/g, 1.23 emu/g, 0.00280 emu/gOe, 43.9 $^{\circ}C$ and 7.99 Oe, 75.84 emu/g, 0.791 emu/g, 0.001937 emu/gOe, 53.8 $^{\circ}C$ respectively. Considering the apparent activation energy changes with oxygen pressure, the combustion reaction significantly depended on initial oxygen pressure and ZnO particle size.

• Journal of Radiation Protection and Research
• /
• v.33 no.2
• /
• pp.53-59
• /
• 2008

We observed DNA damages as a function of mean absorbed dose to identify the indirect effect of high-energy radiation such as x-ray. Monolayer films of lyophilized pGEM-3Zf(-) plasmid DNA deposited on tantalum foils were exposed to Al $K{\alpha}$ X-ray (1.5 keV) for 0, 3, 7 and 10 min, respectively, in a condition of ultrahigh vacuum state. We compared DNA damages by X-ray irradiation with those by 3 eV electron irradiation. X-ray photons produced low-energy electrons (mainly below 20 eV) from the tantalum foils and DNA damage was induced chiefly by these electrons. For electron beam irradiation, DNA damage was directly caused by 3 eV electrons. Irradiated DNA was analyzed by agarose gel electrophoresis and quantified by ImagaQuant program. The quantities of remained supercoiled DNA after irradiation were linearly decreased as a function of mean absorbed dose. On the other hand, the yields of nicked circular (single strand break, SSB) and interduplex crosslinked form 1 DNA were linearly increased as a function of mean absorbed dose. From this study, it was confirmed that DNA damage was also induced by low energy electrons ($0{\sim}10\;eV$) even below threshold energies for the ionization of DNA.

• Journal of Animal Environmental Science
• /
• v.11 no.1
• /
• pp.25-34
• /
• 2005

The study aimed to develop a tractor drawn animal slurry manure sub-soil injector for arable land and thus, can reduce the waste management cost through effective treatment and utilization of animal slurry manure. The application of animal slurry manure to agricultural land will probably be one of the most effective ways to enrich the soil with vital nutrients. However, some existing slurry manure spenders are not suitable in the field because of their adverse effects to the environment. Based on this premise, a prototype was designed and assembled using 5 sub-soiling standards attached to the sin injector device. The traction force of the Prototype measured in the depth of 10 cm and 15 cm from the ground surface of a paddy field was 1,062 kgf and 1,214 kgf, respectively. A unique feature of the machine was that there was an equal volume of slurry manure flowing from each delivery pipe and regulated by a pressurized container that was likewise synchronized with the speed of the tractor The sub-soiling manure injection system can mitigate or reduce the harmful emission of obnoxious gases and malodor during the injection operation.

• Korean Journal of Food Science and Technology
• /
• v.32 no.5
• /
• pp.1128-1134
• /
• 2000

This study was carried out to evaluate quality properties of gamma-irradiated Kwamegi prepared from Cololabis seira semi-dried by cold sea wind. Edible portion of Kwamegi was prepared from whole body, vacuum-packaged, gamma-irradiated in the doses of 3 or 5 kGy, and stored at $5^{\circ}C$ for 60 days. Volatile basic nitrogen and trimethylamine contents were not different by gamma irradiation. During storage increase of those two compounds were inhibited depending upon the dose. Thiobarbituric acid values did not differ in all samples, regardless of irradiation and storage. The amount of total volatile compounds of Kwamegi decreased by irradiation. Rheological properties were not affected by irradiation and were maintained up to 60 day when the Kwamegi was irradiated at 5 kGy dose, but those of control was softened. Sensory evaluation had no differences in all samples immediately after irradiation. Sensory quality of Kwamegi irradiated were organoleptically adequate, however that of control was deteriorated. In conclusion, these results indicate that gamma irradiation technique can be used to maintain the quality of Kwamegi.

• Journal of Sericultural and Entomological Science
• /
• v.53 no.2
• /
• pp.87-91
• /
• 2015

There is no specific data on Entomogenous fungus (DongChungHaCho) in accordance with the silkworm varieties, despite of very high value industrial use as functional materials at domestic and abroad. In this study, we investigated culture condition and characteristics of Paecilomyces tenuipes in 3 silkworm cultivars and 2 specific silkworm breeds. Infection rate of P. tenuipes for silkworm varieties was the highest Kumokjam, followed by Baegokjam, Daeseongjam, Golden silk, Yeonnokjam in that order. The optimum culture conditions were as follows: dark condition, $22^{\circ}C{\pm}1$, and about $4cm^2$ in planting density per pupa. Also, we have developed annual production technologies of P. tenuipes. First, in order that the moisture content of the infection pupa became 3% or less in the natural condition. Second, the dried pupa must be vacuum-packed and was kept under $4^{\circ}C$. Finally, by restoring the moisture content of the dried pupa and culture in optimal condition, the technique for annual production of the P. tenuipes was achieved. Therefore, we expect that the use of Kumokjam and annual production technique will contribute significantly to farm income.