• 한국가구학회지
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• 제28권3호
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• pp.248-258
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• 2017

A study was carried out to observe the 1% aqueous safranine solution flow speed in longitudinal and radial directions of softwood Thuja orientalis L., diffuse-porous wood Gmelina arborea Roxb., and ring-porous wood Phellodendron amurense Rupr., Longitudinal flow was considered from bottom to top while the radial flow was considered from bark to pith directions. In radial direction, ray cells and in longitudinal direction tracheids, vessel and wood fiber were considered for the measurement of liquid penetration speed at less than 12% moisture contents(MC). The variation of penetration speed for different species was observed and the reasons behind for this variation were explored. The highest radial penetration depth was found in ray parenchyma of T. orientalis but the lowest one was found in ray parenchyma of P. amurense. The average liquid penetration depth in longitudinal trachied of T. orientalis was found the highest among all the other cells. The penetration depth in fiber of G. arborea was found the lowest among the other longitudinal cells. It was found that cell dimension and also meniscus angle of safranine solution with cell walls were the prime factors for the variation of liquid flow speed in wood. Vessel was found to facilitate prime role in longitudinal penetration for hardwood species. The penetration depth in vessel of G. arborea was found highest among all vessels. Anatomical features like ray parenchyma cell length and diameter, end-wall pits number were found also responsible fluid flow differences. Initially liquid penetration speed was high and the nit gradually decreased in an uneven rate. Liquid flow was captured via video and the penetration depths in those cells were measured. It was found that even in presence of abundant rays in hardwood species, penetration depth of liquid in radial direction of softwood species was found high. Herein the ray length, lumen area, end wall pit diameter determined the radial permeability. On the other hand, vessel and fiber structure affected the longitudinal flow of liquids. Following a go-stop-go cycle, the penetration speed of a liquid decreased over time.

• Environmental Analysis Health and Toxicology
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• 제26권
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• pp.6.1-6.8
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• 2011

Objectives: The present study investigated the potential adverse effects of multi-wall carbon nanotubes (MWCNTs) on pregnant dams and embryonic development following maternal exposure in rats. Methods: MWCNTs were orally administered to pregnant rats from gestational day (GD) 6 through 19 at dose levels of 0, 8, 40, 200, and 1000 mg/kg/day. During the test period, clinical signs, mortality, body weights, food consumption, serum biochemistry, oxidant-antioxidant status, gross findings, organ weights, and Caesarean section findings were examined. Results: All animals survived to the end of the study. A decrease in thymus weight was observed in the highest dose group. However, maternal body weight, food consumption, serum biochemical parameters, and oxidant-antioxidant balance in the kidneys were not affected by treatment with MWCNTs. No treatment-related differences in gestational index, embryo-fetal mortality, or fetal and placental weights were observed between treated and control groups. Conclusions: The results show that 14-day repeated oral dosing of MWCNTs during pregnancy induces minimal maternal toxicity at 1000 mg/kg/day in rats. Under these experimental conditions, the no-observed-adverse-effect level of MWCNTs is considered to be 200 mg/kg/day for dams and 1000 mg/kg/day for embryonic development.

• 한국정보과학회논문지:소프트웨어및응용
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• 제30권12호
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• pp.1247-1254
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• 2003

현재 경동맥 내막절제술 시행을 위한 경동맥 협착증의 정도 측정에는 디지털감산조영술(DSA), 회전조영술(rotational angiography), 컴퓨터단층조영술(CTA) 및 자기공명조영술(MRA)로부터 얻어진 경동맥의 투영 영상을 이용하여 북미, 유럽 표준 및 총경동맥 방법이 사용되고 있다. 본 논문에서는 기존의 기계적인 측경기를 이용하는 전형적인 경동맥 협착 측정 방법의 단점을 극복하고, 측정자간의 변화율을 최소화하기 위해 자기공명조영술의 단면 영상을 사용하고 컴퓨터화한 새로운 협착증 정도 측정 방법을 개발하였다. 영상 분할에 사용되는 방법중 가장 널리 사용되고 효율적인 명암값 임계치 방법을 사용하여 경동맥 및 동맥의 내강을 분할하였다. 또한, 각 증례의 측정된 총경동맥의 혈관두께를 사용하여 분할된 경동맥으로부터 혈관을 제거 하였고, 혈관이 제거된 경동맥을 혈류 영역과 플라그 영역으로 분할하였다. 각 단면 영상에서의 경동맥 협착증 정도 측정은 (분할된 플라그 영역/혈류영역 및 플라그를 합한 면적) * 100% 식으로 계산된다.

• Journal of Chest Surgery
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• 제54권1호
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• pp.59-64
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• 2021

Background: Diaphragmatic injuries following blunt or penetrating thoraco-abdominal trauma are rare, but can be life-threatening. Rib fractures are the most common associated injury in patients with a traumatic diaphragmatic injury (TDI). We hypothesized that the pattern of rib fracture injuries could dictate the likelihood of acute TDIs. Methods: A retrospective study was carried out between April 2014 and October 2018 to analyze patients with TDIs and rib fractures at a major trauma center in London, United Kingdom. Results: Over the study period, 1,560 patients had rib fractures, of whom 14 had associated diaphragmatic injuries. Left-sided diaphragmatic injuries were found in 8 patients (57%). A significant proportion of the rib fractures were located posterolaterally (44.9%). The highest frequency of fractures was found in ribs 5-10, which accounted for 74% of all the fractures. Ten patients underwent surgery, of whom 7 were diagnosed with a diaphragmatic injury intraoperatively after video-assisted thoracoscopic surgery assessment of the pleural cavity. Two patients died due to severe injuries of other organs and the remaining 2 patients were managed conservatively. Conclusion: Our series of patients demonstrates a relationship between significant rib fractures and diaphragmatic injuries in trauma patients, and the diagnostic difficulties in identifying the condition. We found that the location of the rib fractures and the pattern of injury in patients with TDIs were much lower and posterolateral in the chest wall without a preference for laterality. We suggest using a thoracoscope in patients undergoing chest wall surgery post-trauma to aid in diagnosing this condition.

• 대한방사선기술학회지:방사선기술과학
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• 제45권2호
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• pp.159-164
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• 2022

The study developed a radiation dose measurement program in the radiology laboratory to measure how much exposure the students are exposed to during the radiology class, to request for the improvement and the revision of the current Nuclear Safety Act. The experimental program is shown in the following figure, and experiments were conducted to determine the degree of radiation exposure in the control room with a lead gown at a distance of 1 m, 2 m, and 1 m, and in a control room with a radiographic lead glass wall. The duration of the experiment was 3 months from April to June, when radiation imaging practice classes were conducted, and 128 hours of imaging practice per month were conducted. In order to find out the dose of radiation dose during radiology imaging practice class, the experiment was carried out from April to June for 3 months, and according to the program, the results of exposure dose were 0.34 mSv at 1 m distance, 0.01 mSv at shielding of lead gown at 1 m distance, 0.16 mSv at 2 m distance, and 0.01 mSv at control room with radiation lead glass wall. The exposure dose from the test results was much below the annual general public limit dose of 1 mSv. The restriction on the operation of the radiation equipment in the practice of the students is a regulation that infringes the right of students to learn, and amendments or exemptions of Nuclear Safety Act should be enacted to ensure that it does not violate the fundamental right to learn for students in radiology.

• Anatomy and Cell Biology
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• 제56권3호
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• pp.374-381
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• 2023

Although the epiglottis plays a vital role in deglutition, histological studies of the epiglottis and surrounding ligaments associated with swallowing dysfunction are limited. Therefore, we performed histological observations to clarify age-related changes in the morphological characteristics of the epiglottis and surrounding structures. Tissue samples comprising the epiglottis and surrounding structures were collected from corpses that were both orally fed and tubefed during their lifetimes. Following hematoxylin and eosin, Elastica Van Gieson, and immunohistochemical staining procedures, the chondrocytes, connective tissue, and glandular tissue were observed under the epiglottis epithelium, and intervening adipose tissue was observed in the surrounding area. Fatty degeneration of acinar cells was also observed in the glandular tissue, possibly because of aging. Bundles of elastic fibers were present around the vascular wall in the peri-epiglottic ligament, but some were reduced. Furthermore, large amounts of collagen fibers ran toward and through the cartilage, whereas the mesh-like elastic fibers stopped in front of the cartilage. Microfibrils considered to be oxytalan fibers, which are thinner and shorter than elastic fibers, were observed around the vascular wall and in the fiber bundles. Age-related changes included connective tissue fibrosis shown by the large amount of collagen fibers, atrophy of salivary glands, and an accompanying increase in adipose tissue. Regarding stretchability and elasticity, the elastic fibers may have an auxiliary function for laryngeal elevation during deglutition. This suggests that disuse atrophy of the laryngeal organs with or without oral intake might reduce the amount of elastic fiber in older adults.

• 대한치과기공학회지
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• 제46권1호
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• pp.1-7
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• 2024

Purpose: The goal of this study was to determine the clinical acceptability of various cement space settings for the marginal and internal fit of a zirconia core manufactured using additive manufacturing. Methods: The maxillary right incisor served as the master model. After scanning the maxillary right incisor with a dental 3D (three-dimensional) scanner, the stereo lithography file was created using different cement space settings of 40, 120, and 200 ㎛ using computer-aided design software (Dental System 2018; 3Shape). The marginal and internal fit of the 3 groups were determined using the silicon replica technique. Measurement points were divided into the following three categories: margin, axial wall, and incisal. To ensure more accurate measurements, these three measurement points were divided into 8 points. The Shapiro-Wilk, one-way ANOVA, and Tukey's honestly significant difference test (for all tests α=0.05) were the statistical analyses that were included in the study. Results: The CS (cement space)-200 group had better marginal and internal fit than the CS-40 and CS-120 groups, and there were statistically significant differences at the marginal and incisal points, except for the axial wall points. CS-200 group, both marginal and internal fit were within 120 ㎛, which is the clinically acceptable value. Conclusion: This study suggests that a 200 ㎛ cement space setting is ideal for optimal marginal and internal fit of 3D-printed ceramic crowns.

• 한국산림과학회지
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• 제76권2호
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• pp.161-168
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• 1987

임업기계훈련원(林業機械訓練院)에서 1984년(年) 시범적(示範的)로 임도(林道)를 시설(施設)(10 km)할 목적(目的)으로 10 km를 시공(施工)했는데 1986년(年) 태풍(颱風) 내습시 부분적(部分的)으로 노견붕괴(路肩崩壞)와 측구침식(側溝浸蝕)이 발생(發生)하였다. 이에 대한 원인(原因)을 조사분석(調査分析)한 결과(結果)는 다음과 같다. 측구침식(側溝浸蝕)에 의한 피해(被害)길이는 전림도(全林道) 연장(10km)의 3%에 해당하였으며, 대부분(大部分) 요형사면(凹型斜面)에 사면장(斜面長) 10m 이상(以上)으로 성토(盛土)된 곡선부(曲線部)에서 발생하였고, 부분적(部分的)으로 상수(常水)가 흐르는 계곡부(溪谷部)에 성토(盛土)된 구역(區域)과 상수(常水)가 있는 배수관(排水管)의 유출구(流出口) 양사면(兩斜面)에 성토(盛土)된 부위에서 붕괴(崩壞)가 많이 발생하였다. 측구침식(側溝浸蝕)의 경우 심한 피해(被害)는 계곡수(溪谷水)가 월수(越水)하여 V형(型) 측구(側溝)를 따라 흐르므로서 피해(被害)를 발생시켰으며, 기타 원인(原因)으로는 종단(縱斷)물매가 10% 이상(以上) 급(急)하게 시공(施工)된 지역(地域)에서 나타나 문제점(問題點)으로 인식되고, 직경(直經) 400mm 이하(以下)인 배수관(排水管)이 매설된 집수정(集水井)이 낙엽(落葉) 등(等)의 퇴적(堆積)으로 매몰된 경우와 경사가 급한 침사지(沈砂池)(집수승(集水桝)) 벽이 무너져 내린 결과 이 지점을 월수(越水)하여 측구침식(側溝浸蝕)을 일으키고 있다. 이상(以上)의 결과(結果)에서 시범임도(示範林道)의 태풍피해(颱風被害)는 임도피해예방(林道被害豫防)을 위한 경험부족(經驗不足)에서 나타낸 현상으로 보인다. 상기(上記)와 같은 점을 개선하면 동(同) 시범임도(示範林道) 조성방법(造成方法)은 경제적(經濟的) 임도(林道)차 모델로서 발달될 수 있을 것이다.

• Journal of Periodontal and Implant Science
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• 제38권1호
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• pp.97-102
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• 2008

Purpose: Periodontal intrabony defects have great deal of importance since they contribute to the development of periodontal disease. Current treatment regimens for intrabony defects involve grafting of numerous bony materials, GTR using biocompatible barriers, and biomodification of root surface that will encourage the attachment of connective tissue. Xenograft using deproteinized bovine bone particles seems to be very convenient to adjust because it doesn't require any donor sites or imply the danger of cross infections. These particles are similar to human cancellous bone in structure and turned out to be effective in bone regeneration in vivo. We here represent the effectiveness of grafting deproteinized bovine bone particles in intrabony defect and furcation involvements that have various numbers of bony walls. Materials and methods: Open flap debridement was done to remove all root accretions and granulation tissue from the defects within persisting intrabony lesions demonstrating attachment loss of over 6mm even 3 months after nonsurgical periodontal therapy have been completed. Deproteinized bovine bone particles($BBP^{(R)}$, Oscotec, Seoul) was grafted in intrabony defects to encourage bone regeneration. Patients were instructed of mouthrinses with chlorohexidine-digluconate twice a day and to take antibiotics 2-3 times a day for 2 weeks. They were check-up regularly for oral hygiene performance and further development of disease. Probing depth, level of attachment and mobility were measured at baseline and 6 months after the surgery. The radiographic evidence of bone regenerations were also monitored at least for 6 months. Conclusion: In most cases, radio-opacities increased after 6 months. 2- and 3-wall defects showed greater improvements in pocket depth reduction when compared to 1-wall defects. Class I & II furcation involvements in mandibular molars demonstrated the similar results with acceptable pocket depth both horizontally and vertically comparable to other intrabony defects. Exact amount of bone gain could not be measured as the re-entry procedure has not been available. With in the limited data based on our clinical parameter to measure pocket depth reduction following $BBP^{(R)}$ grafts, it was comparable to the results observed following other regeneration techniques such as GTR.

• 대한소아치과학회지
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• 제24권2호
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• pp.460-474
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• 1997

The purpose of this study was to evaluate and compare the effectiveness of various low-viscosity resin systems used as rebonding agents to prevent microleakage at the margins of class I composite resin restorations. Seventy sound human premolars were selected for experiment. Class I cavities were prepared and each cavity was conditioned with a 37% phosphoric acid for 15 sec, rinsed with water for 15 sec, and dried with compressed air. Bonding agent(Scotchbond Multipurpose, 3M Co.) was applied and a hybrid composite resin (Z-100, 3M Co.) was placed using an incremental technic. The excess cured composite resin was carefully removed with Sof-Lex discs(3M Co.) to expose the original margins of the cavity. The following seven groups were established : group 1 was not rebonded and used as control group ; group 2 was rebonded with a Scotchbond Multipurpose(3M Co.) and finished ; group 3 was rebonded with a Fortify(BISCO) and finished ; group 4 was rebonded with a Concise white sealant(3M Co.) and finished ; group 5 was rebonded with a Concise white sealant(3M Co.) and not finished ; group 6 was rebonded with a P&F sealant(BISCO) and finished; group 7 was rebonded with a P&F sealant(BISCO) and not finished. The specimens were then subjected to 500 thermocycles between 5 & 65 with a 10 see dwell time and immersed in 2% methylene blue dye solution for 24 hours and sectioned with low-speed diamond cutter into two part under water condition. The extent of microleakage at rebonded margins was evaluated microscopically and scored for dye penetration according to the following scale : 0=no dye penetration ; 1=dye penetration to half-way along axial wall between enamel surface and DEJ ; 2=dye penetration beyond halfway along axial wall between enamel surface and DEJ ; 3=dye penetration to the full depth of DEJ or beyond DEJ. Selected samples were prepared for SEM observation to determine the depth of penetration of the rebonding agent into the marginal interface. The obtained results were as follows: 1. In the group 2 and 3, which is rebonded with a Scotchbond Multipupose and Fortify, dye penetration score were decreased significantly than that of group 1 (P<0.05), but group 4 and 6 were not statistically different from group 1(P>0.05). 2. There were significant differences between group 4, 6 and group 5, 7 when compared by dye penetration score (P<0.05). 3. In the SEM observation, Scotchbond Multipurpose and Fortify were penetrated within $30-40{\mu}m$ depth of the outermost surface. However, both sealants were failed to penetrate into the debonded interface.