• Maxillofacial Plastic and Reconstructive Surgery
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• 제28권5호
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• pp.454-469
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• 2006

Today, there is considerable evidence to support a cause-effect relationship between microbial colonization and the pathogenesis of implant failures. The presence of bacteria on implant surfaces may result in an inflammation of the peri-implant mucosa, and, if left untreated, it may lead to a progressive destruction of alveolar bone supporting the implant, which has been named as peri-impantitis. Several maintenance regimens and treatment strategies for failing implants have been suggested. Recently, in addition to these conventional tools, the use of different laser systems has also been proposed for treatment of peri-implant infections. As lasers can perform excellent tissue ablation with high bactericidal and detoxification effects, they are expected to be one of the most promising new technical modalities for treatment of failing implants. It is introduced that Er,Cr:YSGG laser, operating at 2780nm, ablates tissue by a hydrokinetic process that prevents temperature rise. We studied the change of the titanium implant surface under scanning electron microscopy after using Er,Cr:YSGG laser at various energies, irradiation time. In this study, Er,Cr:YSGG laser irradiation of implant fixture showed different effects according to implant surface. Er,Cr:YSGG laser in TPS surface with RBM not alter the implant surface under power setting of 4 Watt(W) and irradiation time of 30sec. But in TPS surface with $Ca_3P$ coating alter above power setting of 2W and irradiation time of 10sec. TPS surface with RBM showed microfracture in 4W, 30sec and TPS surface with $Ca_3P$ coating showed destruction of fine crystalline structure, melting in excess of 2W, 10sec. We concluded that proper power setting, air, water of each implant surface must be investigated and implant surface must be irradiated under the damaged extent.

• 대한소아치과학회지
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• 제24권1호
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• pp.301-312
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• 1997

The purpose of this study was to evaluate the analgesic effect on pulp induced by pulsed Nd : YAG laser according to the power density, irradiated time and the method of application (Non-contact vs contact) in vivo. Experiments were carried out on 90 volunteers who have sound 4 canines. Each canine was grouped by the intensity and the time of irradiation of pulsed Nd : YAG laser was measured. Mean EPT response(units) was measured at 5 min, 30 min, and 60 min after irradiation with various intensity(1.5-3W, 15-30Hz), irradiated time (1.5min, 3min), and application method (Non-contact and contact). The results were as follows: 1. 5 minutes after irradiation, the mean EPT response(units) was increased by 32 % in the non-contact method and by 35% in the contact method of application. Which showed significant difference in mean EPT response(units) compared to not-lased canine in each groups(P<0.05). 2. The mean EPT response(units) with irradiating condition according to the various laser intensity, and the irradiation time stastically did not show significant difference in each groups as time elapsed. 3. There was no significant difference between the non-contact and contact method in the mean EPT response(units). 4. The mean EPT response(units) returned to the baseline value within 30 miuntes. In regard to the above results, the analgesic effect on pulp induced by pulsed Nd : YAG laser resulted a slight increase of pulpal pain threshold, but it was not as high as to replace the role of drug analgesia as whole. This technique can be used for inducing pulpal analgesia as adjunct to other pain control methods and is needed to develop better analgesic effects.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제33권6호
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• pp.617-624
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• 2007

Insulin-like growth factor(IGF) is the most abundant growth factor in bone matrix. Recent studies have shown that it can sensitize apoptotic cell death of osteoblasts. Thus, this study investigated whether IGF-II aggravates irradiation-induced cell death of osteoblasts. Cultured MC3T3 osteoblasts were irradiated and IGF-II was added at the concentration of 50 ng/ml immediately after the irradiation. Cell viability was measured by MTT assay. Changes in cell death and cell cycle were analyzed by flow cytometry. The expression of proapoptotic gene bax and antiapoptotic gene bcl-2 was quantified by real time RT-PCR and Western blot. A dose of 30 Gy caused G2/M arrest and increased cell death through both necrosis and apoptosis, while irradiation from 4 to 10 Gy little affected cell cycle and death. IGF-II treatment reduced cell viability without stimulating cell proliferation and changing cell cycle. Combined treatment of IGF-II with irradiation decreased cell viability and proliferation and increased cell death along with G2/M arrest. These effects were not different from those of irradiation only. At transcriptional and protein levels, IGF-II treatment did not affect bax and bcl-2 expression, whereas irradiation increased the expression ofbax without changes in bcl-2. IGF-II in combination with irradiation showed similar findings. These results suggest that IGF-II could modulate apoptotic cell death through mechanisms other than an imbalance between bax and bcl-2 gene expression, although its effect was overridden by irradiation.

• Food Science and Biotechnology
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• 제14권6호
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• pp.732-737
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• 2005

The combinational effect of gamma irradiation and moist heating on the trypsin inhibitor activity (TIA) in soaked and dried soybeans was evaluated by measuring the inhibition using N-benzoyl-DL-arginine-p-nitroanilide (BAPNA) as substrate. Gamma irradiation significantly decreased the TIA level in soybean at doses above 5 kGy, and the $ID_{50}$ (the gamma irradiation dose required to reach 50% inhibition) value for TIA was 13.53 kGy. Soaking prior to gamma irradiation significantly lowered the $ID_{50}$ to 8.44 kGy, and the soaking process enhanced the efficiency to inactivate TIA by as much as 48%. When soaking prior to gamma irradiation was followed by subsequent mild heating ($60^{\circ}C$) process, the $IT_{50}$ (heating time required to reach the 50% inhibition of TIA) value at even 1 kGy (5.28 min) was greatly reduced by over 50% compared to the level for the no-soaking process. In addition, the activation energy of soaking prior to gamma irradiation at 1 kGy was 2.45 kcal/mole, which was also about 50% lower than the 5.10 kcal/mole of dried soybean gamma-irradiated. Based on these results, soaking prior to gamma irradiation is an effective method for TIA inhibition. Furthermore, a combination of two or more processing methods such as soaking, heating and gamma irradiation is much more effective than any single processing method.

• 한국환경농학회지
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• 제15권1호
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• pp.86-90
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• 1996

본 연구는 LPG를 사용한 방열장치를 이용하여 잡초종자를 열처리한후 처리온도간에 차이가 있다는 판단하에 잡초종자의 발아력에 관계하는 잡초의 종류, 잡초종자의 상태, 조사시간을 실험의 변수로 선택하여 그 주효과 및 각 변수간의 상호작용에 대한 효과를 분석하여 열처리 잡초방제 방법 개발에 필요한 기초자료를 제공하고자 하였다. 실험에 이용된 잡초종자는 화본과인 바랭이(Digitaria sanguinalis S.)와 쌍자엽잡초인 쇠비름(Portulaca oleracea L.)의 건조종자 및 습윤종자(증류수에 24시간 침지)를 사용하였고, 5개의 온도 수준과 8개수준의 조사시간으로 각 종자를 똑같이 처리하였으며 각 처리별로 3회 반복하였다. 본 실험의 결과를 요약하면 다음과 같다. 1) 각 변수에 대한 잡초종자의 발아력은 처리 온도가 $150^{\circ}C$일 때를 제외하고 평균 발아율이 모두(1% 유의수준) 차이가 있는 것으로 분석되었다. 잡초종자의 처리상태에 대해서는 평균 발아율이 $60^{\circ}C$에서는 유의성이 없었으며 $80^{\circ}C$, $100^{\circ}C$, $200^{\circ}C$에서는 1%의 유의수준에서 차이가 있는 것으로 분석되었고 $150^{\circ}C$에서는 5%의 유의수준에서 차이가 있는 것으로 나타났다. 2) 조사시간에 따른 잡초의 평균발아율은 모든 처리온도 수준에서 차이가 있는 것으로 분석되었고(1% 유의수준), 모든 온도수준에서 잡초의 종류와 조사시간 사이에 상호작용이 있는 것으로 나타났다(1%유의수준). 3) 잡초의 처리상태와 조사시간 사이에도 역시 각 온도수준에서 차이가 있는 것으로 나타났고(1% 유의수준), 잡초의 종류와 잡초의 처리상태 간에는 $60^{\circ}C$를 제외한 모든 온도수준에서 차이가 있는 것으로 나타났다(1% 유의수준). 4) 잡초의 평균발아율은 각 온도 수준에서 조사시간에 따라 가장 큰 영향을 받는 것으로 분석되었다.

• 약학회지
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• 제37권5호
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• pp.511-519
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• 1993

The short and variabke transit of drug throught GI tracj and the inter-and intra-subject variations of the transit restrict the sustained drug absorption after oral adminstration. These restrictions may be solved by retaining the dosage forms in the stomach. Then the dosage form will act as a platform which releases the drug slowly and makes the GI absorption occur for a long time. In this study, as the platforms, PVP hydrogels were synthesized by chemical and y-irradiation method in the cylindrical test tube. The chemical method means the synthesis of the hydrogel by heating the mixed solution of N-vinyl-2-pyrrolidone [monomer], acrylated albumin [crosslinking agent], 2, 2'-agobis(2-methylpropionitrile) [initiator] and proxyphylline [drug] at $65^{\circ}C$ for 5 hr. The $\gamma$-irradiation method means the synthesis of the hydrogel by irradiation with $^{60}$ Co $\gamma$-ray of the mixed solution of the monomer, acrylated albumin, and flurbiprofen [drug] at room temperature with total 0.2 Mrad for 3 hr. Our intention is to design the hydrogel tablet (diameter : 1.20 cm, thickness : 0.60 cm) which swells in the gastric fluid after oral administration to such a size that passing through the pylorus could be inhibited during the period of drug release. After releasing drug, the hydrogel should be degraded by the enzymeatic digestion in the stomach, or by hydrolysis and eventually solubilized. Thus, in votro tests were performed to examine the factors that affect swelling and drug release from the PVP hydrogels. Experimental results show that the hydrogels swell to a size larger than the diameter of the pylorus(l.3$\pm$0.7 cm) and the hydrogel prepared by the chemical method is digested by pepsin. But the hydrogel prepared by the $\gamma$-irradiation method was not digested by the pepsin and just collapsed with time. Thus, the swelling of the hydrogel synthesized by $\gamma$-irradiation was independent albumin acrylation time and pepsin concentration. But drug content and radiation dose affected the swelling and drug release kinetics of the hydrogel. Drug release from the hydrigels was prolonged up to about 24 hr. Therefore, it was concluded that by adjusting these factors, the albumin-crosslinked PVP hydrogel synthesized by $\gamma$-irradiation method is expected to be retained in the stomach for up to 60hr and be a potential platform of drugs for long-term GI absorption.

• 한국식품과학회지
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• 제45권1호
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• pp.13-19
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• 2013

반응표면분석법을 이용하여 적양배추 종자의 전자선 처리조건과 재배조건에 따른 새싹채소의 이화학적 및 관능적 품질특성을 분석하여 유통에 적합한 최적조건을 모색하였다. 수분함량의 경우 회귀식의 $R^2$가 0.9638이었고 조사선량 및 재배기간에 많은 영향을 받고 있었다. Total phenolics 함량은 회귀식의 $R^2$가 0.9117이었고 조사선량에 많은 영향을 받았으며, carotenoid 함량($R^2$=0.8338)의 경우 조사선량, 재배기간, 저장기간의 순으로 조건 변수의 영향력이 작용하였다. 관능적 품질 역시 전자선 조사선량에 가장 크게 영향을 받아 선량의 증가에 따라 관능평점이 감소하는 경향을 보여주었다. 재배 및 저장조건의 최적화를 위해 total phenolics 함량 및 전반적 기호도를 superimposing한 결과 최적조건은 조사선량 2.2-3.8 kGy, 재배기간 3.0-4.0일 및 저장기간 2.0-3.0일 범위로 예측되었다.

• 한국염색가공학회지
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• 제5권2호
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• pp.144-148
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• 1993

To increase the moisture content and thereby to reduce the static charge of polyacrylonitrile (PAN), thin layer surface photografting of acylamide (AAm) onto PAN fabrics by using benzophenone as a initiator with a mixtured solvent was carried. The effects of reaction conditions such as monomer, initiator concentrations, UV irradiation time and immersion time of fabrics on grafting were investigated. The percent grafting slightly increased with increasing monomer concentration, benzophenone concentration up to limiting value and thereafter decreased or level offed. The percent grafting was significantly increased with increasing irradiation and immersion times. The moisture regain increased with increasing the percent grafting. The static charge decreased with increasing the percent grafting.

• Journal of Electrical Engineering and information Science
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• 제3권1호
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• pp.68-72
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• 1998

The photomachinable glass-ceramics of Ag and CeO2 doped Li203-SiO2 (LAS)glass system was investigated as a function of UV irradiation time. After the expose and the non-exposed samples were heated, they went under crystalline phase with DTA, SEM, TEM and XRD of normal/high temperature. In this work, crystalline phases, microstructure and dielectric properties were studied under the various time of UV irradiation and heat treatment.

• 한국환경과학회지
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• 제15권11호
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• pp.1061-1067
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• 2006

Photodegradation of endosulfan alpha, beta, and sulfate known as the most toxic substance among organochlorine pesticides by UV irradiation was studied at experimental conditions such as different pH aqueous solution and reaction time. The initial concentration of endosulfan alpha, beta, and sulfate in aqueous solution was 500 ppb, respectively. The experiment of photodegradation was conducted in a quartz reactor equipped with a low pressure mercury lamp (100 W, 240 nm). The samples were withdrawn from the photo reactor at intervals of 0, 10 min, 30 min, 1 hr, 2 hr, and 4 hr. Endosulfan sulfate was never hydrolyzed and photodegraded in wide range of pH. At pH 5 and reaction time (240 min), endosulfan alpha was photodegraded up to 67%. Both endosulfan alpha and beta were started to photodegrade at pH 6.5 with the lapse of time, resulting in approximately 99.9% and 87.2% of photodegradation efficiency, respectively. Furthermore, at pH 9, endosulfan alpha and beta was partially hydrolyzed and photodegraded to 99.5% at 120 min of reaction time. During the photolysis, any photo-products of endosulfan alpha, beta, and sulfate were not observed.