치과응용을 위한 알루미나-유리 복합체 제조

배태성,이민호,강동진,원대희,진영철 大韓齒科器材學會 2000 대한치과재료학회지 Vol.27 No.3

The purpose of this study was to evaluate the mechanical properties of alumina-glass dental composites. Four different borosilicate glasses containing 1, 2, 3, 4 mol% Li₂O were prepared. Porous alumina compacts of 12.0 mm in diameter and 1.0 mm in thickness were prepared with alumina powders of 1.8 and 4.6㎛ by slip casting and sintered at 1,120℃ for 2 hours. Dense composites were made by infiltration of molten glass into partially sintered alumina at 1200℃ for 6 hours. All samples were polished sequentially from #600 to #2,000 diamond disk, and the final surface finishing on the tensile side was received an additional polishing sequence through 0.3㎛ diamond paste. Apparent porosity of alumina-glass composites was measured by means of the KS L3114 method. Biaxial flexure test was conducted by using ball-on-three-ball method at a crosshead speed of 0.5 mm/min. To examine the microstructural aspect of crack propagation, Vickers-produced indentation crack and fracture surfaces were examined by SEM. The results obtained were summarized as follows; 1. Apparent porosity rate decreased according to the increasing with the particle size of alumina. 2. The maximum biaxial flexure strength of 365.26 MPa was obtained with an addition of 4 mol% Li₂O in glass composition. 3. The maximum fracture toughness of3.95 MPa·m½ was obtained with an addition of 3 mol% Li₂O. 4. The crack deflection and crack bridging were the principal strengthening mechanisms in the alumina-glass composites.

용융침투법에 의한 알루미나-유리 복합체의 개발에 대한 연구

배태성,안승근,송창용,원대희,이주형 대한치과기재학회 1999 대한치과재료학회지 Vol.26 No.1

The purpose of this study was to evaluate the mechanical properties of alumina-glass dental composites. Four different borosilicate glasses were prepared, and thermal expansion coefficient was measured from 200 to 600℃. An α-alumina powder with average particle size of 4.6㎛ was used for the matrix. Porous alumina compacts of 12 mm in diameter and 1 mm thickness were prepared by slip casting and sintering at 1100℃ for 2 hours. Dense composites were made by infiltration of molten glass into partially sintered alumina at 1200℃ for 6 hours. Specimens were polished sequentially from #400 to #2000 diamond disk, and the final surface finishing on the tensile side was received an additional polishing sequence through 0.3㎛ diamond paste. Apparent porosity of alumina-glass composites was measured by means of the KS L 3114 method. Biaxial flexure test was conducted by using ball-on-three-ball method at a crosshead speed of 0.5 mm/min. The scanning electron microscopy (SEM) was performed on a polished surface which was etched with 0.5% HF solution for 30 to 40s. The results of this study were obtained as follows; 1. The lowest porosity rate of 26.3% was achieved at the PVA content of 0.013%. 2. The coefficient of thermal expansion of borosilicate glasses showed in the range of 6.30 to 6.30 to 6.46×10-6/℃ 3. The maximum biaxial strength of 383.27 MPa was obtained with an addition of 4mol% ZrO₂. 4. The observation of fracture surfaces of alumina-glass composites indicated the frictional interlocking of jags having a tendency of toughening by crack deflection and crack bridging.

약 내향 비확대 다가사상의 고정점 정리

배종숙;안대종;장우성 명지대학교 자연과학연구소 2004 자연과학논문집 Vol.23 No.-

In this paper, we prove fixed point theorems for weakly inward multivalued nonexpansive maps on a Banach space satisfying Opial condition. 이 논문에서 우리는 Banach 공간에서 Opial 조건을 만족하는 약 내향 비확대 다가사상의 몇 가지 고정점정리를 증명하였다.

중합 광원과 중합 시간이 복합레진의 표면 경도에 미치는 영향

배상만,김대업,이광희,안호영 대한소아치과학회 2001 大韓小兒齒科學會誌 Vol.28 No.2

플라즈마 아크 광원을 사용하는 광중합기를 저출력 할로겐 광원을 사용하는 전통적인 광중합기와 비교 평가하기 위하여 세 종류의 복합레진을 두께가 2, 3, 4, 5mm인 몰드에 충전하고 레진 상면을 할로겐 광으로 40초간 플라즈마광으로 3, 6, 9초간 조사한 후 레진 상면과 하면의 표면미세경도를 각각 측정하였다. 레진시편 상면의 표면경도와 하면의 표면경도 간의 차이는, 두께 2mm 시편에 할로겐 광을 40초간 조사하였거나 플라즈마광을 9초간 조사한 경우들을 제외하고, 모두 유의하였다(P<0.05). 레진시편 상면의 표면경도는 전체 실험군들에서 서로 유의한 차이가 없었다. 레진시편 하면의 표면경도는 전체적으로 보아 할로겐 광을 40초간 조사한 군들에서 가장 높았고 플라즈마광의 조사시간이 감소함에 따라 감소하였으며 레진시편의 두께가 증가함에 따라 감소하였다. 이상의 결과는 복합레진의 중합깊이 측면에서 볼 때 3, 6, 9초간 조사하는 고출력 플라즈마광의 중합능력이 40초간 조사하는 저출력 할로겐광의 중합능력에 미치지 못함을 시사한다. The purpose of study was to compare the plasma are light with the halogen light in compostie resin curing. Three composite resin materials(Z-100. 3M, USA; Tetric Ceram. Vivadent, Liechtenstein; SureFil, Dentsply, USA) were filled in the teflon molds (4mm in diameter and 2,3,4,5mm in thickness) and cured with esther the conventional low-intensity light curing unit with a halogen lamp (Optilux 360, Demetron, U.S.A) for duration of 40 seconds or with the high-intensity light curing unit with a plasma are lamp (Flipo, Lokki, France) for duration of 3, 6, and 9 seconds. The intensity of halogen light was about 370mW/cm2 and that of plasma light was about 1,900mW/cm2. After one week, the surface hardnesses of both the top and the bottom of the resin samples were measured with a microhardness tester(MXT70, Matsuzawa, Japan). There ware significant differences in the hardness between the top and the bottom of the resin samples except the 2mm thickness samples cured by halogen light for 40s or by plasma light for 9s. There was no significant difference between the hardness values of the top surfaces of the thickness groups. The hardness values of the bottom surfaces decreased as the curing time decreased and as the thickness of resin samples increased, and the three kinds of resin composites showed similar patters. The results suggest that the halogen light for 40 seconds might be able to cure greater depth of resin composites than the plasma light far 3, 6, or 9 seconds.

위 윤상근 세포의 Ca^2+-의존성 K^+-전류에 미치는 Ascorbate의 효과

배정원,이무열,방효원,엄대용,이상돈 중앙대학교 의과대학 의과학연구소 1991 中央醫大誌 Vol.16 No.2

In order to observe the effect of ascorbate on the Ca^2+-activated K^+ current in pyloric circular muscle cells which plays a critical role in generation and maintenance of repolarization and automatism, apart of pyloric circular muscle tissue was excised out, digested in collagenase containing Ca^2+-free physiological solution to get single circular muscle cells and the whole cell mode of patch-clamp experiment was conducted. Following results were obtained : 1. Oscillatory outward current was reduced by ascorbate in case of high intrapipette Ca^2+ concentration in whole voltage range and was enhanced in case of low intrapipette Ca^2+ concentration. 2. Oscillatory outward current was reduced in Ca^2+-free physiological solution with calcium channel blocker and not effected by ascorbate. 3. There were no qualitative differences among the control and ascorbate-treated group in effects of pH, steady state inactivation and the remaining component of the outward current. The above results could be concluded that ascorbate effects calcium-dependent component of the oscillatory outward current in the pyloric circular smooth muscle cells.

유리의 조성에서 MgO, Li_2O의 함량변화가 유리침투 알루미나 세라믹 재료의 강도와 색조의 변화에 미치는 영향

배태성,원대희,원상용,윤여은 大韓齒科器材學會 2002 대한치과재료학회지 Vol.29 No.3

This study was performed to investigate the effect of composition changes in glasses on the strength and shade of glass-infiltrated alumina ceramics. Six different borosilicate glasses containing MgO, Li₂O and ZrO₂ in the glass composition were prepared, porous alumina compacts were prepared by slip casting and sintered at 1100℃ for 2 hours. Dense composites were made by infiltration of molten glass into partially sintered alumina at 1110℃ for 6 hours. Specimens were polished sequentially form #800 to #2000 diamond wheel, and the final surface finishing on the tensile side was received an additional polishing sequence through 0.3 ㎛ diamond paste. To evaluate the effect of composition change in glass on the shade changes of glass-infiltrated alumina core ceramics, the color was measured by the CIE L^*, a^*, b^* color scale relative to standard source C. The biaxial flexure strength was measured using the ball-on-three-ball method at a crosshead speed if 0.5mm/min. The color change of composites infiltrated with experimental glasses to In-Ceram Glass AL1 showed that L^* values increased but a^* and b^* values decreased with addition of MgO, Li₂O and ZrO₂ in the glass composition. Maximum color difference of experimental glass-infiltrated alumina core ceramics was obtained in the Group B containing 2.4 mol% MgO in the glass composition. The maximum biaxial flexure strength values 47.41 MPa was obtained in the Group E containing 0.3 mol% Li₂O in the glass composition. The observation of fracture surfaces indicated the microstructurally rough surface with a tendency of toughening by crack deflection and crack bridging.

수유방법 및 기간이 아동의 타액내 환원효소활성검사성적과 유치우식경험도에 끼친 영향

배상만,노동주,김대업,이광희 大韓小兒齒科學會 1996 大韓小兒齒科學會誌 Vol.23 No.3

The purpose of this study was to investigate the effects of the lactation of human or bovine milk and the method of using nursing bottles on the salivary invertase test scores and deciduous caries experience of children. 328 preschool children (boys 178, girls 150) in Iksan city were selected for this study. The parents of the children were asked to answer the questionnaire about the lactation of human or bovine milk and the time of using nursing bottles. The data were obtained from the salvary invertase activity score,(Resazurin Disc Test) deciduous caries experience and the questionnaire. The result were as follows. The invertase activity and caries experience of the human milk higher than that of the bovine milk group(p<0.05). There were significant positive relationships between the lactation period and the invertase activity and between the lactation period and the caries experience(p<0.05). Caries experience had a tendency to increase as the time of using nursing bottles increase(p>0.05).

A Study on Protection of Maternal Antibody against Hantavirus in Rats

우영대,--,--,--,--,-- 대한의생명과학회 2005 Biomedical Science Letters Vol.11 No.1

The etiologic agents of haemorragic fever with ranal syndrom (HFRS) in Korea are Hantaan and Seoul virus in the genus Hantavirus, family Bunyaviridae. In order to elucidate the role of maternal immunity to Hantavirus infection in rats, the protective effect of the maternal antibody were studies by using rats experimentally infected with Seoul virus strain HR80-39. Antibody titers of sera and viral antigen against Seoul virus were investigated by indirect immunofluorscence antibody technique (IFA). The dam sera had IFA antibody titers ranging from 1:128 to 1:1,024 after parturition. In fetuses, IFA antibody titers ranged from 1:16 to 1:64 just after birth, increased to peak titers ranged from 1:256 to 1:1,024 in the 2nd week after birth. Challenged newborn rats had IFA antibody titers ranging from 1:64 to 1:1,024 after inoculation. No viral antigen was detected in lungs or other organs of the newborn rats. The maternal antibody to Seoul virus was transferred prenatally through placenta and postnatally via colostrum from immune dams to their offspring. These results demonstrated that maternal antibody to Seoul virus was quite effective in protecting newborn rats against same virus infection.

제7차 교육과정에 따른 함수영역의 수준별 문항개발 및 평가방법

박대연,고안상,유흥상,김윤배 전주대학교 교육문제연구소 2000 敎育論叢 Vol.15 No.-

가성부갑상선기능저하증 1예

김대영,박길선,배일헌,김성진,차상훈,한기석 충북대학교 의과대학 충북대학교 의학연구소 1997 忠北醫大學術誌 Vol.7 No.1

가성부갑상선기능저하증은 부갑상선 호르몬의 말단 작용 기관인 신장과 골이 부갑상선 호르몬에 적절히 반응하지 않아 발병하는 매우 드문 유전성 질환이다. 작은 키, 짧은 손가락, 둥근 얼굴, 짧은 목 등의 신체적인 특징이 있으며, 혈액검사에서는 저칼슘혈증, 고인산혈증의 소견을 보이며 저칼슘혈증에 의한 발작으로 발현할 수 있다. 방사선과적인 소견으로는 양성 중수골 징후, 뇌 기저핵의 칼슘 침착 등의 소견이 있다. 저자는 전형적인 방사선학적 소견을 가진 가성부갑상선기능저하증례을 경험하였기에 보고하고자 한다. The pseudohypoparathyroidism is a rare heritable disorder that is caused by parathyroid hormone resistance of target organs(mainly the kidney and skeleton). Clinically, the short stature, short digits, short neck and round face are characteristic somatic features and hypocalcemic seizure is a common manifestation. Radiologically, the positive metacarpal sign and calcification of basal ganglia are characteristic features of pseudohypoparathyroidism. Authors report a case of pseudohypoparathyroidism with typical radiologic findings.