• 구강회복응용과학지
• /
• 제28권2호
• /
• pp.213-221
• /
• 2012

장기적인 칫솔질시 외부 stain 처리된 IPS e.max Press 도재의 색의 변화를 분광측색장치(SpectroShade$^{TM}$)를 이용하여 측정하고 비교함으로써 외부 stain의 색 안정성을 평가해 보고자 한다. IPS e.max Press LT ingots shade a1(Ivoclar Co.,Liechtenstein)를 사용하여 블록 형태의 시편을 제작하였으며 Orange, A, B, C, D shade로 외부 stain 처리 하였다. 칫솔질 기계를 이용하여 1년(11,000회), 2년(22,000회), 4년(44,000회), 6년(66,000회), 8년(88,000회) 치의 칫솔질 운동을 수평적으로 시행하였다. SpectroShade$^{tm}$ MICRO(MHT, Italy)를 이용하여 색조 변화를 측정하였다. 1년치(11,000회)의 칫솔질 연마 후 Orange shade에서 다른 4개의 shade보다 더 크게 색 차이가 나타났다. 그 후 칫솔질 횟수가 증가하여도, 외부 stain의 shade에 따른 색 차이의 변화는 통계적으로 유의성이 없었다. 칫솔질의 횟수의 증가에 따른 색 차이의 변화량은 일정한 증가나 감소의 경향을 보이지 않고 불규칙하였으며 통계학적으로 유의한 차이가 발견되지 않았다. 칫솔질이 IPS e.max Press 도재의 외부 stain의 변화에 크게 영향을 미치지 않으며 임상적으로도 외부 stain의 색 안정성이 인정된다고 생각된다. 추후 외부 stain에 영향을 미칠 수 있는 다른 요인들에 대한 연구도 필요하리라 사료된다.

• 대한치과보철학회지
• /
• 제35권2호
• /
• pp.344-356
• /
• 1997

The purpose of this study was to evaluate the long term tooth-brushing effect on the color change of specially treated IPS Empress porcelain surface. Staining techique with blue stain and liquid was used. The surfaces of the specimen were treated with 5% and 10% Hydrofluoric acid, 50mm and 250mm alumina sandblast, and then blue stain and liquid were used for external stain. After 29,200, 58,400, 87,600, 116,200 brushing strokes (equivalent to 2, 4, 6, 8 years each), color changes of the stained layer were measured with spectrophotometer(CM-3500d, MINOLTA, Tolkyo, Japan). The result of this study was obtained as follows : 1. The color changes were great after 29,200 tooth brushing strokes in every group, but from 29,200 strokes to 116,800 strokes, there were no significant color changes in each group. (p>0.05) 2. The greastest color changes were observed in 5% HF treated group and the least color changes were observed in $50{\mu}m$ aluminar sandblast treated group in every stroke (p<0.05), but no statistical difference between groups compared with control group (p>0.05). According to these results, pretreatment of I.P.S. Empress porcelain with alumina sandblast improved the color stability It is thought that about 8 year-tooth brushing strokes does not change the color of IPS Empress porcelain significantly on this condition, but long term follow-up will be needed.

• Journal of Advanced Marine Engineering and Technology
• /
• 제31권6호
• /
• pp.761-767
• /
• 2007

We have developed novel optical-fiber sensors based on strain-induced long-period fiber gratings for monitoring the deformation of a hull. They have no external pressure for sustaining the mechanical formed gratings. The pressure, which provides a force to form the periodic grating along the single mode fiber, was realized by the bonding strength of a photopolymer. To reduce the polarization dependency of the sensors caused by the asymmetry structure of gratings, a Faraday Rotator Mirror (FRM) was utilized in this experiment. We have realized the polarization-insensitive function of the proposed sensors. The change of an external strain are measured by an optical spectrum analyzer. When the external stain increases. the attenuation at the resonant wavelength decreases and the loss peak was slightly shifted to the shorter wavelength.

• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 2003년도 하계학술대회 논문집 Vol.4 No.1
• /
• pp.577-580
• /
• 2003

The magnetostriction of FeCoGe/phenol composites, which is one of the magnetostrictive materials, measured at the external magnetic field. The measurement was carried out using the electrical-resistance strain gage, the wheaten's Bridge for eliminating the unnecessary voltage, and the lock-in-amp for signal amplification and noise filtering. When the external magnetic field was applied in the longitudinal the samples, the maximum strain of 120ppm was taken with regard to the 10wt.% phenol composite. This results indicate that the FeCoGe/phenol composites can be useful as an actuator because it has larger stain than the other solid state actuators such as piezo electric materials.

• 대한세포병리학회지
• /
• 제5권1호
• /
• pp.1-9
• /
• 1994

The cytological and ultrastructural findings of Pneumocystis carinii(PC) obtained from rats by bronchoalveolar lavage (BAL) are described. All developmental forms of the PC organisms were obtained in the lavage fluid. Papanicolaou stain revealed conglomeration of PC as a foamy cast. The cystic walls of PC were well identified on Gomori's methenamine silver stain. Trophozoites and intracystic bodies were stained by Giemsa and Diff-Quik techniques. Some PC organisms were seen within the alveolar macrophages. Ultrastructurally, the cysts were almost circular in shape, and were nearly devoid of surface tubular extensions. The wall of the cyst was composed of an unit membrane, an intermediate electron lucent layer and an external electron dense layer The cysts frequently contained intracystic bodies, so called sporozoites. Occasionally empty or collapsed cysts with no intracystic bodies, and precysts were found. Trophozoites were variable in size and shape with abundant tubular extensions along the single electron dense pellicle. BAL is a useful method for concentrating the various morphologic forms of PC organisms, and is a rapid diagnostic method for PC pneumonia.

• Journal of the Korean Wood Science and Technology
• /
• 제49권5호
• /
• pp.471-481
• /
• 2021

This study investigated the hygroscopicity and UV deterioration characteristics of 3 domestic and 4 imported woods using natural oil, stain, and varnish paints. In terms of hygroscopicity, it was found that the hygroscopicity of the painted wood was lower than that of the unpainted wood, and that as the number of coatings increased, the hygroscopicity decreased. In terms of anti-absorption, oil-based chemical paints showed higher resistance than water-based paints, and natural oils showed results comparable to oil-based paints. As for the UV deterioration, the amount of color change of the painted wood was lower than that of the unpainted wood, and there was no significant difference according to the number of times of painting. The amount of color change was found to be low in oil-based paints and hardwoods. Through this study, we confirmed effective moisture blocking and small color changes during painting using paints, and it is believed that wood can be protected from internal and external defects through selective and efficient painting based on data for excellent painting performance.

• 치과방사선
• /
• 제16권1호
• /
• pp.41-48
• /
• 1986

It is known that radiation therapy is a kind of treatment choices of the maxillofacial tumors. This study is designed to investigate the irradiation effects on rat's periodontal tissues as functional tissues which relate to tooth-support, hard tissue formation and destruction. 20 rats (Sprague-Dowley branch, male) were devided into control group of 4 and experimental groupe of 16. Experimental group was singly exposed to Co-60 irradiation with 10 Gy in the head and neck region. Animals were sacrificed on 2 days, 1 week, 2 weeks and 3 weeks after the irradiation. The specimens were observed by histopathological examination employing H-E stain, van-Gieson stain and PA-ACH fluorescent stain. The results were as follows: 1. Cementoblasts and osteoblasts were gradually lost and rearranged along the external surfaces of the cementum and alveolar bone, but osteoclasts were almost not affected. 2. The cell numbers of the periodontal ligament were decreased due to the cellular atrophy and degeneration, but recovered almost normally on the 3rd week after irradiation. 3. The collagen fibers within the periodontal ligament were irregularly oriented, became finer and decreased in number. 4. The vessels of the periodontal ligament were decreased at the initial stage but increased again on the 2nd week after irradiation, and the hemorrhagic appearances, occurred within the tissues, due to the arterial destruction, were lasted until 3 weeks after irradiation. 5. The glycogen within the periodontal ligament was gradually increased and stored in the matrices of the cemental side on the 1st week after irradiation, but recovered almost normally on the 3rd week after irradiation.

• 대한용접접합학회:학술대회논문집
• /
• 대한용접접합학회 2004년도 춘계 학술발표대회 개요집
• /
• pp.264-266
• /
• 2004

for the kぉ mechanics analysis of a crack in a weld of dissimilar steels, residual stress analysis and fracture analysis must be performed simultaneously. The standard definition of the J-integral leads to a path dependent value in the presence of a residual stress field. And unlike cracks in homogeneous materials, a bimaterial interface crack always induces both opening and shearing modes of stress in the vicinity of the crack tip. Therefore, it is necessary to develope a path independent J-integral definition for a crack in a residual stress field generated by welding of dissimilar steels. This paper addresses the modification of the Rice-J-integral to produce a path independent J-integral when residual stresses due to welding of dissimilar steels and external forces are present. The residual stress problem is heated as an initial stain problem and the J-integral proposed for this class of problems is used And a program which can evaluate the 1-integral for a crack in a weld of dissimialr steels is developed using proposed J-integral definition.

• Archives of Plastic Surgery
• /
• 제41권4호
• /
• pp.325-329
• /
• 2014

Background Liposuction is a procedure to reduce the volume of subcutaneous fat by physical force. Intracellular storage fat is composed of triglyceride, whereas circulating fat particles exist as cholesterol or triglycerol bound to carrier proteins. It is unavoidable that the storage form of fat particles enters the circulation system after these particles are physiologically destroyed. To date, however, no studies have clarified the fatal characteristics of fat embolism that occurs after the subclinical phase of free fat particles. Methods A mixture of human lipoaspirate and normal saline (1:100, 0.2 mL) was injected into the external jugular vein of rats, weighing 200 g on average. Biopsy specimens of the lung and kidney were examined at 12-hour intervals until postoperative 72 hours. The deposit location and transport of the injected free fat particles were confirmed histologically by an Oil Red O stain. Results Inconsistent with previous reports, free fat particles were transported from the intravascular space to the parenchyma. At 24 hours after infusion, free fat particles deposited in the vascular lumen were confirmed on the Oil Red O stain. At 72 hours after infusion, free fat particles were accumulated compactly within the parenchymal space near the perivascular area. Conclusions Many surgeons are aware of the fatal results and undiscovered pathophysiologic mechanisms of free fat particles. Our results indicate that free fat particles, the storage form of fat that has been degraded through a physiological process, might be removed through a direct transport mechanism and phagocytotic uptake.

• 한국임상수의학회지
• /
• 제23권3호
• /
• pp.291-299
• /
• 2006

During long bone lengthening, there are many disadvantages including axial deviation, malalignment and re-fracture which are commonly encountered inspite of its proven abilities. To study the effects of intramedullary K-wire application on the lengthening of long bone, ten skeletally mature mongrel dogs were separated into two groups(Group I, II). Right femurs of group I(5 dogs) were fixed with only monolateral external fixator after subperiosteal osteotomy. Right femurs of group II(5 dogs) were fixed with mono lateral external fixator and intramedullary K-wire after subperiosteal osteotomy. Lengthening was started at 7 days after the surgery with the rate of 0.5 mm per day for 5 weeks and the dogs were sacrificed after 15 weeks postoperatively to examine histologic differences and evaluate bone mineral density. Radiographic examination at an interval of two weeks was done to evaluate the type of callus formed and to analyze complications including instability of external skeletal fixation and axial deviation. Bone mineral density at the lengthened area and contralateral nonlengthened area were measured using quantitative computerized tomography. Histological examination of regenerated bone was performed using Masson's trichrome stain method. The radiographs demonstrated poor callus formation, higher incidence of axial deviation and screw loosening in the group I compared to the group II. The bone mineral density at the lengthened area in the group II was higher than that of the group I(P<0.05). Histological examination showed that the new bone trabeculae in the group II were greater than that of the group I. In conclusion, the combination of monolateral external fixator and intramedullary K-wire can prevent pin loosening, axial deviation and reduce healing period in dogs.