• Title/Summary/Keyword: slow release

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Effects of Aralia cordata Thunb. on Proteoglycan Release, Type II Collagen Degradation and Matrix Metalloproteinase Activity in Rabbit Articular Cartilage Explants

  • Baek, Yong-Hyeon;Seo, Byung-Kwan;Lee, Jae-Dong;Huh, Jeong-Eun;Yang, Ha-Ru;Cho, Eun-Mi;Choi, Do-Young;Kim, Deog-Yoon;Cho, Yoon-Je;Kim, Kang-Il;Park, Dong-Suk
    • Journal of Acupuncture Research
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    • v.22 no.2
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    • pp.191-201
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    • 2005
  • Background & Objective: Articular cartilage is a potential target for drugs designed to inhibit the activity of matrix metalloproteinases (MMPs) to stop or slow the destruction of the proteoglycan and collagen in the cartilage extracellular matrix. The purpose of this study was to investigate the effects of Aralia cordata Thunb. in inhibiting the release of glycosaminoglycan (GAG), the degradation of collagen, and MMP activity in rabbit articular cartilage explants. Methods : The cartilage-protective effects of Aralia cordata Thunb. were evaluated by using glycosaminoglycan degradation assay, collagen degradation assay, colorimetric analysis of MMP activity, measurement of lactate dehydrogenase activity and histological analysis in rabbit cartilage explants culture. Results : Interleukin-la (IL-1a) rapidly induced GAG, but collagen was much less readily released from cartilage explants. Aralia cordata Thunb. significantly inhibited GAG and collagen release in a concentration-dependent manner. Aralia cordata Thunb. dose-dependently inhibited MMP-3 and MMP-13 expression and activities from IL-1a-treated cartilage explants cultures when tested at concentrations ranging from 0.02 to 0.2 mg/ml. Aralia cordata Thunb. had no harmful effect on chondrocytes viability or cartilage morphology in cartilage explants. Histological analysis indicated that Aralia cordata Thunb. reduced the degradation of the cartilage matrix compared with that of IL -1a-treated cartilage explants.

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Release Behavior and Characterization of PCL Microcapsules Containing Lemongrass Oil (레몬그라스 오일을 함유하는 PCL마이크로캡슐의 특성과 방출거동)

  • Park, Jong-Kwon;Kim, Ji-Eun;Jeong, Noh-Hee
    • Applied Chemistry for Engineering
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    • v.26 no.3
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    • pp.341-346
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    • 2015
  • In this study, poly ${\varepsilon}$-caprolactone(PCL) microcapsules containing lemongrass oil was prepared by the solvent evaporation method. Effects of concentrations of PCL and poly vinyl alcohol (PVA) as well as stirring speeds when preparing microcapsules were investigated. Specific peaks of lemongrass oil in PCL microcapsules at 1600 and $2900cm^{-1}$ were observed by FT-IR. The particle size and shape of microcapsules were also measured by polarizing microscope and optical microscopy. The average particle size of microcapsules decreased with increasing the stirring rate. At the stirring speed of 1500 rpm, and 1 wt% of each PCL and PVA concentrations, the smallest particles were formed. Collection efficiencies of lemongrass oil of 77.5% and 69.5% were obtained when 1.5 wt% of PCL and 2 wt% of PVA were used, respectively. In addition, the release behavior and antioxidant activity of lemongrass oil from PCL microcapsules were examined using UV-Vis spectrophotometry. When 0.5 wt% PCL and 2.0 wt% PVA were used with the slow stirring rate, microcapsules showed a fast release rate. The characteristics of antioxidant activity exhibited similar to that of the release behavior.

Liposome-Microencapsulation of Lysozyme and Its Stimulated Release (Lysozyme의 Liposome 미세캡슬화와 유출 촉진)

  • Kim, Tae-Jong;Kim, Young-Sook;Pyun, Yu-Ryang
    • Korean Journal of Food Science and Technology
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    • v.28 no.3
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    • pp.399-404
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    • 1996
  • Encapsulation of lysozyme using lecithin vesicles and its stimilated release properties were studied. Lecithin vesicles were prepared by the dehydration-rehydration (DR)method. The highest encapsulation efficiency (EE) value of 80.1% was obtained by sonicating the multilamellar vesicles (MLVs) at 100 KHz for 120 min in bath sonicator. The value of entrapment progressively increased with the concentration of lysozyme, while the EE value decreased with the increase of enzyme concentration up to 50mg per 100mg per 100mg of lecithin, and then became nearly constant. At the pH of 5.9, only a small amount of lysozyme was released from DR vesicles during incubation at $37^{\circ}C$ As the pH decreased to 3.0, lysozyme was released more rapidly. Lysozyme release was accelerated for 24h and reached a plateau after 72h incubation with 1% Tween 80, $Ca^{2+}$ gave a pulse-like-release in the first hour, which was followed by a slow release.

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Dissolution Properties of Phosphate Glasses with Trace Elements

  • Lee, Hoi-Kwan;Kang, Won-Ho
    • Journal of the Korean Ceramic Society
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    • v.42 no.6 s.277
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    • pp.371-376
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    • 2005
  • Phosphate glasses were prepared by melting quenching process, and glass formation and dissolution properties were studied. The glass forming region in the $K_2O-CaO-P_2O_5$ system is quietly agreed with the report by Mazurin OV et al. with $M_2O-M'O-P_2O_5$ system (M : monovalent cation, M'divalent cation). Conditionally these glasses have solubility from absorbing the moisture or water and then release elements with trace elements, and the thermal and chemical properties were controllable by the $CaO,\;K_2O,\;P_2O_5$ contents. In the abnormal glass properties, this paper showed the possibility the present glasses can be a good candidate for one component of the slow released agriculture fertilizer.

Prospects and Effect of Forest Fertilization (산지(山地) 시비(施肥)에 관(關)한 고찰(考察))

  • Lee, Chun Yong;Park, Bong Woo
    • Journal of Korean Society of Forest Science
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    • v.77 no.1
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    • pp.109-115
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    • 1988
  • Decrease of the planting area reduced fertilized area of forest. To accomplish the aims of natural regeneration, mini-rotation plantation, diminishing the rotation length, maintaining healthy forest and production of good quality timber, forest fertilization should be continued. In order to improve the deteriorate situation, slow-release fertilizer applied on top soil needs to be developed and aerial application will give diminished cost. Fertilization with tending before tree felling in forest will increase the effect of fertilizer more, Proper quantity of fertilizer by tree species and soil fertility should be found out in the future, Street trees, environmental forest near city and ornamental trees in the residential areas could be also included in this field.

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An Investigation of the Effect of Schotky Barrier-Height Enhancement Layer on MSMPD Dynamic Characteristics

  • Seo, Jong-Wook
    • JSTS:Journal of Semiconductor Technology and Science
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    • v.2 no.2
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    • pp.141-146
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    • 2002
  • The effect of the wide-bandgap Schottky barrier enhancement cap layer on the performance of metal-semiconductor-metal photodetectors (MSMPD's) is presented. Judged by the dc characteristics, no considerable increase in recombination loss of carriers is resulted by the incorporation of the cap layer. However, about 45% of the detection efficiency is lost for the cap-layered MSMPD's even with a graded layer incorporated under pulse operation, and it was found to be due mainly to the capturing and slow release of the photocarriers at the heterointerface. The loss mechanism of the pulse detection efficiency is believed to be responsible for the intersymbol interference and the increased bit-error-rate (BER) observed in MSMPD's when used with a high bit rate pseudo-random-bit-stream (PRBS) data pattern.

RESPONSES TO MONENSIN AND OESTRADIOL IN STEERS GRAZING TWO TROPICAL PASTURES IN N. E. QUEENSLAND

  • Jones, R.J.;Minson, D.J.
    • Asian-Australasian Journal of Animal Sciences
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    • v.3 no.3
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    • pp.183-186
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    • 1990
  • Monensin administered as a slow release capsule to Droughtmaster steers grazing mixed pastures containing Stylosanthes hamata or grass pastures fertilized with N, had no effect on growth rate over 111 day period. Monensin significantly increased the level of propionic acid (p<0.001) and decreased the level of butyric acid (p<0.01) in the rumen. The lack of response to monesin was partly attributed to the poor pasture conditions and growth rate of the steers during part of the experimental period. An implant of oestradiol improved growth rates during the period of poor forage quality and in the subsequent 56 days when pastures were of high quality following rain. Mean growth rates over the entire 157 days for control, monensin and monensin/oestradiol treatments were 0.37, 0.37 and 0.50 kg/d respectively. It was concluded that when pasture conditions are sufficient only for the maintenance of liveweight, production can be improved by an oestradiol implant but not by feeding an ionophore such as monensin.

The Effect of Compound Fertilizer Contained Slow Release Nitrogen on Turfgrass Growth in Kentucky bluegrasss and on Nitrogen Change in Root Zone (완효성질소성분이 함유된 복합비료의 시비가 토양 중 질소함량 변화 및 켄터키블루그래스 생육에 미치는 영향)

  • Kim, Young-Sun;Kim, Tack-Soo;Ham, Suon-Kyu;Bang, Su-Won;Lee, Chang-Eun
    • Asian Journal of Turfgrass Science
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    • v.23 no.1
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    • pp.101-110
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    • 2009
  • This study was conducted to investigate the effect of compound fertilizer contained slow release nitrogen such as isobutylidene diurea(IBDU) and methylene urea(MU) on kentucky bluegrasss and the change of nitrogen in the root zone after supplying these at AM turfgrass research institute with soil analysis, chlorophyll content index, leaf area index and dry weight during 6 months from July to December in 2007 year. Fertilizer treatments were designed as following; non-fertilizer(NF), straight fertilizer(CF), methylene urea(MU), isobutylidene diurea(IBDU). The every treatments were arranged a randomized complete block with three replications. Results obtained were summarized as follows: As relative to time after N fertilizers application, ammonium and nitrate in soil were increased, but T-N was decrease. The change of ratio of available Nand T-N by elapsed time after fertilizing was decreased in CF from 30days but increased until 45days. Compared with NF, the turf color index in CF, MU and IBDU was increased 1.5%, 2.5% and 2.3%, respectively, the chlorophyll content 16%, 25% and 26%, the dry weight 31%, 62% and 46% and shoot number 104%, 185% and 148%. The chlorophyll content index of MU and IBDU was increased 7.5% and 8.8% than that of CF, shoot number 40% and 22%, and dry weight 24% and 12% but turf color index was similar to that of CF. These results showed that the MU and IBDU application was supplied nitrogen for a long time in root zone by increasing an available nitrogen, and so promote turf grass growth such as chlorophyll content and shoot number in kentucky bluegrass.

Effect of Various Nitrogen Fertilizers on Rice Yield in Direct Seeding on Dry Paddy (건답 직파재배 논에서 질소비료 형태에 따른 시용효과)

  • Park, Chol-Soo;Jung, Yeong-Sang;Lee, Ho-Jin;Joo, Jin-Ho;Seo, Jun-Han
    • Korean Journal of Soil Science and Fertilizer
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    • v.33 no.5
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    • pp.318-324
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    • 2000
  • Field experiment was conducted on a sandy clay loam paddy field in the Experimental Farm of the Kangwon National University for four years from 1995 to 1998 to evaluate the effect of different nitrogen fertilizers on soil property and rice yield. The size of each experimental plot was 75 m2. Basal application of fertilizer to the paddy field was on late April, and rice (cv. Odae) was sown with drill seeding on early May. Irrigation was done at 3 leaf stages after rice seeding. Electrical conductivity in soils treated with phosphate- and resin coated slow release fertilizers were relatively greater than those of the other fertilizer application. Available $P_2O_5$ concentration in soils after rice harvest increased significantly compared that in soil before field trial. Rice yield in transplanting culture were $6.516kg\;ha^{-1}$. The rice yield in the direct seeded paddy was 81.9 percents of the yield in the transplanted paddy. The rice yield in phosphate coated slow release fertilizer was the highest among various fertilizer trials in directly seeded dry paddy, while rice yield was the lowest in the organic fertilizer plus urea application. Rice yield between organic fertilizer plus urea and organic fertilizer application were not significantly different. The green manuring effect of rye in the direct seeded rice paddy in Chuncheon was low due to low temperature and short growth period.

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