• Restorative Dentistry and Endodontics
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• 제14권2호
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• pp.5-19
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• 1989

The purpose of this study was to observe the microleakage of composite resin filling using several glass ionomer cements. The Class V cavities of eighty noncarious human molars were prepared at the cementoenamel juction on the facial and lingual surfaces of each tooth with a No.330 carbide bur in a high speed handpiece. The cavity dimensions were $3.0{\pm}0.5mm$ wide, $2.0{\pm}0.5mm$ high, and $1.5{\pm}0.5mm$ deep and all enamel cavosurface margins were beveled with a No.558 carbide bur in low speed handpiece. The bevel was approximately $45^{\circ}$ and 0.5-1.0mm in width. A total of the 160 cavities was divided into four groups, and then 144 cavities among them were three experimental groups and remaining sixteen cavities were control group. All of the prepared cavities were restored as follows: group 1 : Preparations were restored with there three glass ionomer cements. group 2 : Preparations were restored with a composite resin with three glass ionomer cement bases placed $0.2{\pm}0.1mm$ short of the cavosurface margin. group 3 : Preparations were restored with a composite resin with three glass ionomer cement bases extened to the cavosurface margin. group 4 : As control group, preparations were restored with a composite resin, PALFIQUE. The specimens were then thermocycled in a range of $6^{\circ}C-60^{\circ}C$ and immersed in a bath of 2.0% aqueous basic fuchsin solution for 24 hours. Dye penetration was read on a scale of 0 to 4 by Tani and Buonocore's method. The following conclusions were derived from the results obtained; 1. All groups showed significantly more leakage at the gingival margins than at the occlusal margins(p<0.0005). 2. At the gingival margins, group 1 showed less leakage than group 3(p<0.01) and group 4(p<0.0005), while group 3 exhibited less leakage than group 2(p<0.01) and group 4(p<0.0005). 3. At the occlusal margins, group 4 showed less leakage than group 3(p<0.1) and group 1(p<0.005), while group 3 exhibited less leakage than group 2(p>0.1) and group 1(p<0.025).

• Journal of Oral Medicine and Pain
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• 제33권4호
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• pp.383-386
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• 2008

골수염이란 엄밀히 따지면 수질골 부위의 염증을 의미하지만 대개 피질골, 골막까지 함께 이환된다. 급성에서는 주로 통증과 간헐적인 고열, 하순의 감각 저하, 통증 등의 임상적 양상이 나타날 수 있고, 초기에 발견되지 못하거나 적절한 치료가 이루어지지 않는다면 만성 골수염으로 진행되게 된다. 골수염은 치료 시기가 늦어질수록 치료에 대한 반응이 더디거나 예후가 좋지 않을 수 있고, 병리학적 골절 등 합병증 또한 증가하기 때문에 발생 초기 단계에서 세심한 병력 청취와 주의 깊은 임상 검사가 필수적이다. 본 증례에서처럼 측두하악장애 유사 증상으로만 나타나더라도 통상적인 관련 치료에 반응하지 않고 악화되는 경우, 통상적인 안면 방사선사진 외에 방사선 동위원소를 사용한 골스캔 촬영이나 전산화 단층촬영 등 부가적인 진단 검사를 적극적으로 시행하는 것이 바람직할 것으로 사료된다.

• Journal of Periodontal and Implant Science
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• 제30권1호
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• pp.203-212
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• 2000

Putrefactive activity within the oral cavity is the principal cause of halitosis. The most common intraoral sites of oral malodor production are tongue, interdental and subgingival areas. The other foci may include faulty restorations, sites of food impaction and abscesses. Periodontal disease frequently involves pathological oral malodor, which is caused mainly by volatile sulfur compounds(VSC), such as hydrogen sulfide, methyl mercaptan, and dimethyl sulfide. The purpose of this study is to evaluate the association between oral malodor and periodontal status. Volatile sulfur compounds in mouth air were estimated by portable sulfide monitor($Halimeter^{TM}$). The results were as follows : 1. The levels of volatile sulfur compounds were significantly greater in a periodontitis group than in a control group(P<0.01). The amounts of VSC in mouth air from patients with periodontal involvement were four times greater than those of the control group. 2. The significant positive correlation was found between VSC concentrations and the number of pocket depth above 4mm(P<0.01), but correlation between VSC concentrations and plaque score was not statistically significant(P>0.05). 3. In the periodontitis group, VSC concentrations of pre-treatment significantly decreased after scaling and root planing(P<0.01). 4. No statistically significant correlation was found between VSC concentrations and sex / age in the periodontitis group. The above results indicate that periodontal disease may play a role as an important factor of oral malodor and deep periodontal pockets are a source of volatile sulfur compounds.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2004년도 제22회 춘계학술대회논문집
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• pp.634-643
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• 2004

In this paper are presented a concept of a new supersonic air inlet, which is designated a Multi-Row Disk (MRD) inlet, aiming at performance improvement under off-design conditions, and results of wind tunnel tests examined performance characteristics of the MRD inlet. The MRD inlet is frequently called ‘a skeleton inlet’ because of its appearance. The performance of a conventional axisymmetric inlet with a solid center body (spike) deteriorates under off-design Mach number conditions. It is due to the fact that total pressure recovery (TPR) governed by the throat area of inlet and mass capture ratio (MCR) governed by an incidence position of an oblique shock from the spike tip into the cowl can not be controlled independently in such air inlet. The MRD inlet has the spike that is composed of a tip cone and several disks arranged downstream of it, based on the experimental fact that several deep cavities on a conical surface have little negative effect on the boundary layer growth. The overall spike length of the MRD inlet is adjustable to the given flight speed by changing space between disks so that a spillage flow can be controlled independently from controlling the throat area. It could be made clear from the result of wind tunnel tests that the MRD inlet improves TPR by 10% compared with a conventional inlet with a solid spike under off-design conditions.

• Applied Science and Convergence Technology
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• 제26권4호
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• pp.79-85
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• 2017

The crack-free AlGaN template has been successfully grown by using selective area growth with triangular GaN facet. The triangular GaN stripe structure was obtained by vertical growth rate enhanced mode with low growth temperature of $950^{\circ}C$ and high growth pressure of 500 torr. The lateral growth rate enhanced mode of AlGaN for crack-free and flat surface was also investigated. Low pressure of 30 torr and high V/III ratio of 4400 were favorable for lateral growth of AlGaN. It was confirmed that the $4{\mu}m$ -thick $Al_{0.2}Ga_{0.8}N$ was crack-free over entire 2-inch wafer. The dislocation density of $Al_{0.2}Ga_{0.8}N$ was as low as ${\sim}7.6{\times}10^8/cm^2$ measured by cathodoluminescence. Based on the high quality AlGaN with low dislocation density, the ultraviolet laser diode epitaxy with cladding, waveguide and GaN/AlGaN multiple quantum well (MQW) was grown by metalorganic chemical vapor deposition. The stimulated emission at 349 nm with full width at half maximum of 1.8 nm from the MQW was observed through optical pumping experiment with 193 nm KrF laser. We also have fabricated the deep ridge type ultraviolet laser diode (UV-LD) with $5{\mu}m-wide$ and $700{\mu}m-long$ cavity for electrical properties. The turn on voltage was below 5 V and the resistance was ${\sim}55{\Omega}$ at applied voltage of 10 V. The amplified spontaneous emission spectrum of UV-LD was also observed from pulsed current injection.

• Applied Microscopy
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• 제51권
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• pp.5.1-5.7
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• 2021

The olfactory organs of two African lungfishes, Protopterus amphibius and P. dolloi, were investigated using a stereo microscope and a compound light microscope and were described anatomically, histologically, and histochemically. Like other lungfishes, these species present the following general features: i) elongated olfactory chamber (OC), ii) anterior nostril at the ventral tip of the upper lip, iii) posterior nostril on the palate of the oral cavity, iv) lamellae with multiple cell types such as olfactory receptor neurons, supporting cells, basal cells, lymphatic cells, and mucous cells (MC), and vi) vomero-like epithelial crypt (VEC) made of glandular epithelium (GE) and crypt sensory epithelium. Some of these features exhibit differences between species: MCs are abundant in both the lamellar and inner walls of the OC in P. amphibius but occur only in lamellae in P. dolloi. On the other hand, some between feature differences are consistent across species: the GE of both P. amphibius and P. dolloi is strongly positive for Alcian blue (pH 2.5)-periodic acid Schiff (deep violet coloration), and positive with hematoxylin and eosin and with Masson's trichrome (reddish-brown staining), unlike the MCs of the two species which stain dark red with both Alcian blue (pH 2.5)-periodic acid Schiff and Masson's trichrome but respond faintly to hematoxylin and eosin. The differing abundance of MCs in the two lungfishes might reflect different degrees in aerial exposure of the olfactory organ, while the neutral and acid mucopolysaccharide-containing VEC, as indicated by staining properties of the MCs, is evolutionary evidence that P. amphibius and P. dolloi are the closest living relatives to tetrapods, at least in the order Dipnoi.

• Restorative Dentistry and Endodontics
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• 제34권5호
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• pp.406-414
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• 2009

본 연구의 목적은 심부 상아질과 치수실 상아질에 $H_2O_2$를 각기 다른 적용시간과 농도로 적용하였을 때, 레진수복물과의 미세인장결합강도에 미치는 영향을 평가하는 것이다. 준비된 각각의 치아에 전형적인 근관와동을 형성하고 다음과 같이 무작위로 1개의 대조군과, 4개의 실험군으로 나누었다: 1군, 전처리를 시행하지 않았다; 2군, 20% $H_2O_2$를 20분, 10분, 5분간 적용하였다; 3군, 10% $H_2O_2$를 20분, 10분, 5분간 적용하였다; 4군 5% $H_2O_2$를 20분, 10분, 5분간 적용하였다; 5군, 2.5% $H_2O_2$를 20분, 10분, 5분간 적용하였다. 위와 같이 처리한 후 와동 내를 Superbond C&B(Sunmedical, Co., Shiga, Japan)로 충전하였다. 각 치아는 $37^{\circ}C$ 증류수에 24시간 저장한 뒤 심부 상아질과 치수실 상아질로 잘라 미세인장결합강도 시험을 시행하였다. 각 군에서 측정된 미세인장결합강도를 3-way ANOVA와 Tukey post hoc test로 통계 처리하였다(p < 0.05). 실험 결과 모든 군에서 심부 상아질(D1)의 미세인장 결합강도가 치수실 상아질(D2)보다 높게 나타났다. 평균 결합강도는 $H_2O_2$의 농도와 적용 시간이 증가할수록 감소하였다. 통계분석에서 상아질의 깊이, $H_2O_2$ 농도와 적용 시간이라는 세 가지 변수간의 교호작용 효과는 없으나(p > 0.05). 상아질의 깊이와 $H_2O_2$ 농도 사이, $H_2O_2$ 농도와 적용 시간 사이에서는 교호작용 효과가 있었다(p < 0.05). SEM 관찰에서는 $H_2O_2$의 농도가 증가할수록 상아세관이 좀 더 개방된 양상을 보였다.

• Bulletin of the Korean Chemical Society
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• 제30권6호
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• pp.1285-1292
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• 2009

Large single crystals of zeolite, |$Na_{75}$|[$Si_{117}Al_{75}O_{384}$]-FAU (Na-Y, Si/Al = 1.56), were synthesized from gels with composition of 3.58Si$O_2$ : 2.08NaAl$O_2$ : 7.59NaOH : 455$H_2$O : 5.06TEA : 2.23TCl. One of these, a colorless single-crystal was ion exchanged by allowing aqueous 0.02 M CsOH to flow past the crystal at 293 K for 3 days, followed by dehydration at 673 K and 1 ${\times}\;10^{-6}$ Torr for 2 days. The crystal structure of fully dehydrated partially $Cs^+$-exchanged zeolite Y, |$Cs_{45}Na_{30}$|[$Si_{117}Al_{75}O_{384}$]-FAU per unit cell (a = 24.9080(10) $\AA$) was determined by single-crystal X-ray diffraction technique in the cubic space group Fd $\overline{3}$ m at 294(1) K. The structure was refined using all intensities to the final error indices (using only the 877 reflections with $F_o\;>\;4{\sigma}(F_o))\;R_1$ = 0.0966 (Based on F) and $R_2\;=\;0.2641\;(Based\;on\;F^2$). About forty-five $Cs^+$ ions per unit cell are found at six different crystallographic sites. The 2 $Cs^+$ ions occupied at site I, at the centers of double 6-ring (D6Rs, Cs-O = 2.774(10) $\AA$ and O-Cs-O = 88.9(3) and 91.1(3)$^o$). Two $Cs^+$ ions are found at site I’ in the sodalite cavity; the $Cs^+$ ions were recessed 2.05 $\AA$ into the sodalite cavity from their 3-oxygen plane (Cs-O = 3.05(3) $\AA$ and O-Cs-O = 77.4(13)$^o$). Site-II’ positions (opposite single 6-rings in the sodalite cage) are occupied by 7 $Cs^+$ ions, each of which extends 2.04 $\AA$ into the sodalite cage from its 3-oxygen plane (Cs-O = 3.067(11) $\AA$ and O-Cs-O = 80.1(3)$^o$). The 26 $Cs^+$ ions are nearly three-quarters filled at site II in the supercage, being recessed 2.34 $\AA$ into the supercage (Cs-O = 3.273(8) $\AA$ and O-Cs-O = 74.3(3)$^o$). The 4 $Cs^+$ ions are found at site III deep in the supercage (Cs-O = 3.321(19) and 3.08(3) $\AA$), and 4 $Cs^+$ ions at another site III’ (Cs-O = 2.87(4) and 3.38(4) $\AA$). About 30 $Na^+$ ions per unit cell are found at one crystallographic site; The $Na^+$ ions are located at site I’ in the sodalite cavity opposite double 6-rings (Na-O = 2.578(11) $\AA$ and O-Na-O = 97.8(4)$^o$).

• 대한수의학회지
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• 제27권2호
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• pp.167-183
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• 1987

The anatomical structure of the Skeleton of thoracic limb of thirty-one adult Korean native goats(body weight: 14~17kg) was observed after skeletal preparation, and the osteometry was performed in each bone. The results were as follows; 1. The thoracic limb of the Korean native goat was composed of scapula, humerus, radius, ulna, carpal bones, metacarpal bones, phalanges and sesamoid bones. 2. The scapula was flat and triangular in shape. There were no distinct tuber of spine and acromion in the spine. The subscapular fossa was deep and triangular in shape and the vertebral border was sigmoid form. The coracoid bone was formed as the coracoid process at the medial aspect of the supraglenoid tubercle but the clavicle wa.s not observed. The left and right scapular indexes were 57.92 and 58.31 and the glenoid cavity indexes were 89.23 and 86.82, respectively. 3. The greater tubercle of the humerus was devided into cranial and caudal parts. The third tubercle was observed and the face for the infraspinatus muscle was rectangular form. The left and right humerus indexes were 32.44 and 32.63, the head indexes were 94.13, 96.62 and the trochlear-epidondyle indexes were 67.32 and 65.81, respectively. 4. The radius and ulna were fused entirely except at the broad proximal and narrow distal interosseous spaces. The ulna was longer than the radius, and its reduced body and distal end were fused at the caudomedial surface of the radius. 5. The carpal bones were six in number. There were radial, intermediate, ulnar, accessory, second-third and fourth carpal hones in carpal bones. 6. The metacarpal bone was composed of a large metacarpal bone resulted from the fusion of the third and fourth metacarpal bones, and there was a metacarpal tubercle at the dorsolateral part of the proximal end. There were no vestiges of the second and fifth metacarpal bones. 7. The digits were composed of third and fourth digits and each digit was composed of the proximal, middle and distal phalanges. 8. The sesamoid bones were six in number. There were two at the fetlock joint and one at the coffine joint palmarly in each digit. 9. The ratios of the lengths among the scapula, humerus, antebrachium and metacarpal bone were 1.42 : 1.47 : 1.77 : 1.00 in the left and 1.42 : 1.45 : 1.77 : 1.00 in the right, respectively.

• 한국임상수의학회지
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• 제28권6호
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• pp.566-570
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• 2011

본 연구에서는 난소자궁적출술에 있어서 티타늄(titanium) 클립 적용 시 발생할 수 있는 합병증을 평가하고, 난소혈관과 난소걸이인대의 두 가지 결찰법을 비교하여 합병증을 최소화 할 수 있는 수술법을 찾고자 하였다. 실험을 위해 6마리의 암컷 비글견이 사용되었으며, 세 마리씩 두 그룹으로 나누어 한 그룹은 난소걸이인대와 난소혈관을 함께 결찰 하였고, 나머지 한 그룹은 난소걸이인대를 결찰하지 않고 난소혈관만 결찰 하였다. 두 수술법을 비교하기 위해서 매달 1회씩 1년 동안 복강 X-ray 검사를 통해 적용된 클립의 위치 변화를 확인하였고, 적용된 클립에 의한 염증반응 유무는 혈액검사를 통해 확인하였다. X-ray 검사 상에서 두 그룹의 클립 위치는 큰 변화를 보이지 않았으며, 혈액 검사에서도 거의 모든 수치들이 정상범위에 있었고, 염증과 관련된 임상증상 또한 관찰되지 않았다. 부검을 통한 두 그룹의 클립 포매 형태를 관찰한 결과 난소걸이인대를 결찰한 클립은 복강의 얇은 막으로 두껍게 싸여서 신장 후연에 위치하고 있는 것을 확인하였고, 난소걸이인대를 결찰하지 않은 클립은 얇게 둘러싸인 막 표면에 위치하여 신장의 아래쪽에서 관찰되었다. 이러한 결과는 난소걸이인대가 클립의 움직임을 최소화 할 수 있도록 지지해주는 역할을 하는 것을 의미하며, 따라서 티타늄 클립을 적용하는 난소자궁적출술에서 난소걸이인대를 함께 결찰하는 방법이 합병증 예방에 있어서 보다 적합한 방법으로 생각된다.