• Title/Summary/Keyword: Slow release

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Radiographic Bone Density Around Immediately Placed Titanium Implant on the Extraction Socket of Diabetic and Insulin-Treated Rat Maxilla (당뇨쥐 상악에서 발치후 즉시 식립 임플란트 주위골의 방사선 골밀도)

  • Park, Kun-Hyun;Park, Su-Hyun;Lee, Sung-Hwy;Pyo, Sung-Woon
    • Maxillofacial Plastic and Reconstructive Surgery
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    • v.32 no.5
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    • pp.389-395
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    • 2010
  • Purpose: Although it is generally accepted that patients with controlled diabetes have similar rates of success for dental implants as healthy individuals, the use of dental implants in diabetic patients is controversial. In addition, the impact of diabetes on the healing of bone associated with immediately place dental implants is not completely understood. The purpose of this study was to measure bone response to implants radiologically in uncontrolled and insulin-controlled diabetic rats. Materials and Methods: Twenty rats were divided into control, insulin-treated and diabetic groups. The rats received streptozotocin (60 mg/kg) to induce diabetes; animals in the insulin-treated group also received three units of subcutaneous slow-release insulin. Two titanium implants ($1.2{\times}3$ mm) were placed in the extraction socket of the maxillary first molars of the animals and were harvested at 3 days, 1, 2 and 4 weeks. The bone density was measured by digital radiography using gray-level analysis (histogram) in the regions of interest (ROI) at four points: two mesial and two distal to both sides of the implant. Results: The results showed that the osseointegration of the implants was impaired in the diabetic rats compared to the control and the insulin-treated rats. The radiographic evidence demonstrated marked destruction of bone around the implants in the diabetic group. Both the control and the insulin-treated groups had a significantly higher bone density on radiograph than the diabetic group from the 1 week of the experiment (P<0.05 for each comparison). Conclusion: The present study revealed that the immediate placement of titanium implants in the maxilla of diabetic rat lead to delay in the maturation of bone adjacent to implants. It is expected that the reduced predictability of success of immediate implantation in patient with the uncontrolled diabetes.

Hydrogen Storage and Release Properties for Compacted Ti-Mn Alloy (컴팩션된 Ti-Mn계 합금의 수소저장 및 방출 특성)

  • KIM, JONG SEOK;HAN, WON BI;CHO, HYUN SUK;JEONG, MOON SUN;JEONG, SEONG UK;CHO, WON CHUL;KANG, KYOUNG SOO;KIM, CHANG HEE;BAE, KI KWANG;KIM, JONG WON;PARK, CHU SIK
    • Transactions of the Korean hydrogen and new energy society
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    • v.28 no.1
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    • pp.9-16
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    • 2017
  • Hydrogen forms metal hydrides with some metals and alloys leading to solid-state storage under moderate temperature and pressure that gives them the safety advantage over the gas and liquid storage methods. However, it has disadvantages of slow hydrogen adsorption-desorption time and low thermal conductivity. To improve characteristics of metal hydrides, it is important that activation and thermal conductivity of metal hydrides are improved. In this study, we have been investigated hydrogen storage properties of Hydralloy C among Ti-Mn alloys. Also, the characteristics of activation and thermal conductivity of Hydralloy C were enhanced to improve kinetics of hydrogen adsorption-desorption. As physical activation method, PHEM (planetary high energy mill) was performed in Ar or $H_2$ atmosphere. Hydralloy C was also activated by $TiCl_3$ catalyst. To improve thermal conductivity, various types of ENG (expanded natural graphite) were used. The prepared samples were compacted at pressure of 500 bar. As a result, the activation properties of $H_2$ PHEM treated Hydralloy C was better than the other activation methods. Also, the amounts of hydrogen storage showed up to 1.6 wt%. When flake type ENG was added to Hydralloy C, thermal conductivity and hydrogen storage properties were improved.

Soil Fertility Status of Arableland in Korea and Their Management Practices Required (우리나라경토의 비옥도현황과 시비관리대책)

  • 박천서
    • KOREAN JOURNAL OF CROP SCIENCE
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    • v.37 no.4
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    • pp.383-396
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    • 1992
  • In order to find out the reasons for the excessive accumulation of certain fertilizer elements in arable land in Korea, which may be a detrimental factor for her sustainable agriculture in the future, total requirement of fertilizers were estimated from the huge number of soil test data obtained throughout the country using the fertilizer requirement models based on the soil analysis data and the concepts of multi nutrient factor balance or starter fertiliazer. The total fertilizer requirements estimated based on the present soil fertility status were much less than those estimated from the suspected cropping area of various crops cultivated depending on the conventional fertilizer recommendation for each crops or the actual amount of fertilizer elements consumed through National Agricultural Cooporative Federation(NACF). The excessive accumulation of certain fertilizer elements in arable land in Korea must be due to excessively high dose of chemical fertilizers as well as those farm wastes such as animal wasts produced unexpectedly in large amounts or crop residues. And it is suggested that the improved fertilizer recommendation must be developed in consideration both with the soil fertility status and the amounts of nutrient removal by each crop, and that the high analyzed complex fertilizers commonly used by farmers must ugently be developed in a form containing low P and K with Mg and slow release type N for the better balanced management practices of soil fertility by farmers arid for their practices of sustainable agriculture.

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Use of Phosphate Coated Urea to Decrease Ammonia Volatilization Loss from Direct Seeded Rice Field at Early Stage (건답(乾畓) 직파(直播) 논에서 초기(初期)의 암모니아 휘산(揮散) 경감(輕減)을 위한 인산(燐酸) 입힌 요소(尿素)의 효과(效果))

  • Jung, Yeong-Sang;Ha, Sang-Keun;Cho, Byung-Ok;Lee, Ho-Jin
    • Korean Journal of Soil Science and Fertilizer
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    • v.29 no.1
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    • pp.8-14
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    • 1996
  • Use of phosphate coated urea to decrease ammonia volatilization from directly seeded paddy under dryland condition at early stage was tested. Effect on urea hydrolysis was investigated through laboratory study comparing with use of thiourea, a urease inhibitor, under different water content. A field measurement of volitilized ammonia with phosphate-glycerol ammonia absorber was conducted for surface treated urea, phosphate coated urea, phosphate coated slow-release fertilizer and organic fertilizer. Through laboratory study, hydrolysis rate of phosphate coated urea at three days after treatment was lower than that of urea, however, the rate after one week was same. Thiourea addition retarted urea hydrolysis. By field measurement, ammonia volatilization was effectively reduced by use of phosphate coated urea.

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Biological markers around immediately placed titanium implant in the extraction socket of diabetic and insulin-treated rat maxilla

  • Park, Su-Hyun;Heo, Hyun-A;Lee, Won;Pyo, Sung-Woon
    • Journal of the Korean Association of Oral and Maxillofacial Surgeons
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    • v.38 no.4
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    • pp.204-211
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    • 2012
  • Objectives: Dental implants installation in patients with diabetes remains controversial as altered bone healing around implants has been reported. And little is known about the biological factors involved in bone healing around implants. The present study aimed to investigate the biological markers around immediately placed implants in rats with controlled and uncontrolled diabetes. Materials and Methods: Twenty rats (40 sites) were divided into the control, insulin-treated and diabetic groups. The rats received streptozotocin (60 mg/kg) to induce diabetes; animals in the insulin-treated group also received three units of subcutaneous slow-release insulin. Two threaded titanium alloy implant ($1.2{\times}3mm$) were placed in the extraction socket of the both maxillary first molars and allowed for healing. Bone blocks including implant were harvested at 3 days, 1, 2 and 4 weeks. The levels of bone morphogenetic protein (BMP)-4, transforming growth factor (TGF)-${\beta}1$, osteocalcin (OC) and osteonectin (ON) were measured in the peri-implant osseous samples by RT-PCR. Results: The BMP-4 level increased immediately in all groups by day 3, then decreased abruptly in the control and the insulin-treated groups. However, by week 4, all groups showed mostly the same amount of BMP-4 expression. The level of TGF-${\beta}1$ also instantly increased by day 3 in the insulin-treated group. This level elevated again reaching the same values as the control group by week 4, but was not as high as the diabetic group. In addition, the expression of OC and ON in the control and insulin-treated groups was higher than that of the diabetic group at 2 weeks and 4 weeks, indicating active bone formation in these groups. Conclusion: The immediate placement of titanium implants in the maxilla of diabetic rat led to an unwanted bone healing response. Conclusively, the results of this study suggest that immediate implant insertion in patients with poorly controlled diabetes might be contraindicated.

Selection of Proper Medium and Amount of Applied Fertilizer for Exportable Cymbidium Young Plants Grown in Korea (수출용 심비디움 묘 생산에 적합한 배지 선발 및 시비량 구명)

  • Shim, Myung-Syun;Kim, Mi-Seon
    • Journal of Bio-Environment Control
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    • v.19 no.4
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    • pp.217-222
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    • 2010
  • Bark is a general medium for potted Cymbidium in Korea, but it is difficult to shake off or eliminate the medium from the roots before exporting the potted plants. This working process can injure the roots and then deteriorate plant marketability. This study was carried out to select the optimum medium easier to eliminate from the roots instead of bark and the optimum amount of applied fertilizer to improve the plant growth. Cymbidium young plants 'Honey Hot' and 'Desert Look' were planted in pots with bark, cocochip, and peatmoss. The plants were treated with 2, 4, and 6 g of slow release fertilizer. The plant growth characteristics were investigated in the first and second years during production period of three years. The medium characteristics and mineral nutrient content of the leaves were also examined in the second year. In the first year, the plant growth of 'Desert Look' was improved in all peatmoss treatments more than bark. 'Honey Hot' showed the highest plant growth values in the bark treatment. In the second year, the plant growth of the two cultivars was improved in peatmoss. Cocochip treatments showed the lower plant growth values than bark and peatmoss in the first and second year. There was no significant difference among fertilizer amounts in all the media. The higher CEC values of peatmoss medium resulted to higher capacity to hold more nutrients than bark, and the nutrient retention of the peatmoss improved the plant growth. The higher K and Ca contents in the leaves would contribute to improve the plant growth. Consequently, it would be possible to use peatmoss instead of bark for Cymbidium young plants, but there must be always attention to appropriately water the medium and manage the moisture.

Influence of Cilnidipine on Catecholamine Release Evoked by Cholinergic Stimulation and Membrane Depolarization in the Perfused Rat Adrenal Gland

  • Lim, Dong-Yoon;Woo, Seong-Chang;Ko, Suk-Tai
    • Proceedings of the Korean Society of Applied Pharmacology
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    • 2001.11a
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    • pp.95-95
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    • 2001
  • Ciinidipine (FRC-8635) is a newly synthesized novel DHP type of organic Ca$\_$2+/channel blockers that have been developed so far in Japan (Yoshimoto et al., 1991 : Hosono et at., 1992). It also has a blocking action on L-type voltage-dependent Ca$\^$2+/channel (VDCCs) in the rabbit basilar artery (Oike et al., 1990) and a slow-onset and long-lasting hypotensive action in clinical and experimental studies (Ikeda et al., 1992 ; Tominaga et al., 1997). Recent electrophysiological data indicate that cilnidipine might be a dual-channel antagonist for peripheral neuronal N-type and vascular L-type Ca$\^$2+/channels (Oike et al., 1990 ; Fujii et al., 1997; Uneyama et at., 1997). However, little is known about the involvement of N-type VDCCs in contributing to the muscarinic receptor-mediated CA secretion. Therefore, the present study was attempted to investigate the effect of cilinidipine on secretion of catecholamines (CA) evoked by ACh, high K$\^$+/, DMPP and McN-A-343 from the isolated perfused rat adrenal gland. Cilnidipine (1-10 ${\mu}$M) perfused into an adrenal vein for 60 min produced dose- and time-dependent inhibition in CA secretory responses evoked by ACh (5.32${\times}$10$\^$-3/M), DMPP (10$\^$-4/ M for 2 min) and McN-A-343 (10$\^$-4/ M for 2 min). However, lower dose of lobeline did not affect CA secretion by high K$\^$+/(5.6${\times}$10$\^$-2/ M), higher dose of it reduced greatly CA secretion of high K$\^$+/. Cilnidipine itself did also fail to affect basal catecholamine output. Furthermore, in adrenal glands loaded with cilnidipine (10 ${\mu}$M), CA secretory response evoked by Bay-K-8644 (10 ${\mu}$M), an activator of L-type Ca$\^$2+/channels was markedly inhibited while CA secretion by cyclopiazonic acid (10 ${\mu}$M), an inhibitor of cytoplasmic Ca$\^$2+/-ATPase was no affected. Moreover, $\omega$-conotoxin GVIA (1 ${\mu}$M), given into the adrenal gland for 60 min, also inhibited time-dependently CA secretory responses evoked by ACh and high K$\^$+/.

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Phosphorus and Nitrogen Rate Effects to a Newly Seeded Kentucky Bluegrass (질소와 인산의 시비량이 새로 조성된 Kentucky Bluegrass에 성장에 미치는 영향)

  • Lee, Sang-Kook
    • Asian Journal of Turfgrass Science
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    • v.25 no.2
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    • pp.217-222
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    • 2011
  • Professional turfgrass applicators have reduced or eliminated phosphorus from their fertilization programs based on the assumption that soil phosphorus levels are supplying adequate amounts of phosphorus to the turfgrass. The previous researchers found that there were no P effects for turfgrass growth especially for mature turf. No effects may result from high P level in heavy thatch layer. The research was conducted for one year to investigate the effects of phosphorus fertilization programs on turfgrass performance, and monitor soil and plant tissue nutrient levels to determine the impact of the programs on a newly seeded Kentucky bluegrass. The nitrogen treatments were 20, 30 and $40g\;m^{-2}\;yr^{-1}$. The low, medium, and high nitrogen treatments were applied over 2, 4 and 6 applications, respectively. Nitrogen was applied using a formulation containing 30% of slow and 70% of fast release nitrogen sources that are representative of typical home lawn fertilizers. The phosphorus treatments were 0, 10 and $20g\;m^{-2}\;yr^{-1}$. Phosphorus was applied according to the application schedule for the nitrogen treatments. Kentucky bluegrass was seeded in May, 2010. The thickness of thatch layer was less than 1 cm and the first treatment was applied to Kentucky bluegrass in April, 2011. The low N rate treatment had acceptable color and quality ratings without high clipping yields. The high N rate treatment consistently had the highest color and quality ratings but also had very high clipping yields in comparison to the low and medium N rate treatments. Although there are significant differences in tissue P, Overall, there was no effect of phosphorus on color, quality, or clipping weights.

Studies on the Development of Compound Fertilizer for Raising Rice Seedling in Trays for Machine Transplanting -I. Manufacture of Compound Fertilizer (수도상자육묘용(水稻箱子育苗用) 전용복합비료(專用複合肥料) 개발연구(開發硏究) -I. 비료(肥料) 제조시험(製造詩驗))

  • Choi, Du-Hoi;Yuk, Chang-Soo;Shin, Jae-Sung;Han, Ki-Hak
    • Korean Journal of Soil Science and Fertilizer
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    • v.22 no.2
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    • pp.100-104
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    • 1989
  • This study was carried out in order to develop a compound fertilizer for raising rice seedling in trays. A compound fertilizer, a trail product, was manufactured using the major fertilizer sources of ammonium sulfate, diammonium phosphate and potassium chloride in combination with zeolite and glutamic acid fermentation waste. Besides, polyacrylamide for slow release control of the fertilzer and Tachigaren and sulfuric acid for reducing the occurrence of seedling rot were used. The component ratios of N, $P_2O_5$ and $K_2O$ of trial product were 4.19, 5.41 and 4.05 percent respectively. The dissolution rate of nitrogen component in water for the trial product with polyacrylamide was lower about fifteen percents than the product without polyacylamide in six hours. Hymexazole, main component of Thachigaren, from the product was released about 86.2 percents in forty eight hours. When the product with polyacylamide applied on red earth soil and paddy soil, the pH of soil ranged from 4.6 to 5.4 for 25 days experiment.

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Effects of Synchronization of Energy and Nitrogen Release in the Rumen on the Starch Disappearance in the Gastrointestinal Tract and Growth Performance of Hanwoo Steers

  • Li, Dong-Hua;Oh, Young-Kyoon;Lee, Sang-Rak;Choi, Seong-Ho;Un, Ok-Ji;Seol, Yong-Joo;Nho, Whan-Gook;Moon, Sang-Ho;Kim, Kyoung-Hoon
    • Journal of Animal Science and Technology
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    • v.53 no.6
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    • pp.533-540
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    • 2011
  • The objectives of experiments were to compare directly the effects of synchrony of slowly fermented (corn and corn gluten meal; C-CGM) and of rapidly fermented ingredients (barley and soybean meal; B-SBM) in the rumen on starch disappearances in gastrointestinal tracts (Experiment 1) and growth performance (Experiment 2) of Hanwoo steers in the feedlot barn. In experiment 1, four Hanwoo steers ($288{\pm}21$ kg) fitted with ruminal and "T" shaped duodenal cannula were placed in one pen with Calan gate and assigned randomly to a duplicate $2{\times}2$ Latin square design. In experiment 2, eight intact Hanwoo steers ($311{\pm}8$ kg) were assigned randomly to one of two pens with Calan gate to evaluate the effect of the same diets as like in experiment 1 on growth performance. There were no differences in ruminal pH, ammonia and total VFA concentrations between treatments. Percentage of apparent ruminal starch disappearance was 33.3% unit lower (p<0.05) for steers fed C-CGM than for steers fed B-SBM diets and this difference resulted in 268% higher (p<0.05) in duodenal starch flows for steers fed C-CGM diet than for steers fed B-SMB diet. There was significant increase (p<0.05) in quantity (927 vs. 400 g/d) of corn starch digested post-ruminally compared to barley starch. However, percentage of starch apparently digested post-ruminally was 8% higher (p=0.1) in steers fed fast synchrony diet with B-SBM than in steers fed slow synchrony diets with C-CGM. The differences of percentage and amount of starch apparently digested post-ruminally between C-CGM and B-SBM diets did not affect rice straw DM intake, average daily gain (ADG) and feed efficiency. In conclusion, there is some uncertainty in regards to the relationship between site of starch digestion and DM intake, ADG, and feed efficiency in this study.