• The Journal of Advanced Prosthodontics
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• 제12권2호
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• pp.75-82
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• 2020

PURPOSE. The aim of this study was to investigate the shear bond strength of luting cements used with implant retained restorations on to titanium specimens after different surface treatments. MATERIALS AND METHODS. One hundred twenty disc shaped specimens were used. They were divided into three groups considering the surface treatments (no treatment, sandblasting, and oxygen plasma treatment). Water contact angle of specimens were determined. The specimens were further divided into four subgroups (n=10) according to applied cement types: polycarboxylate cement (Adhesor Carbofine-AC), temporary zinc oxide free cement (Temporary CementZOC), non eugenol provisional cement for implant retained prosthesis (Premier Implant Cement-PI), and non eugenol acrylic-urethane polymer based provisional cement for implant luting (Cem Implant Cement-CI). Shear bond strength values were evaluated. Two-way ANOVA test and Regression analysis were used to statistical analyze the results. RESULTS. Overall shear bond strength values of luting cements defined in sandblasting groups were considerably higher than other surfaces (P<.05). The cements can be ranked as AC > CI > PI > ZOC according to shear bond strength values for all surface treatment groups (P<.05). Water contact angles of surface treatments (control, sandblasting, and plasma treatment group) were 76.17° ± 3.99, 110.45° ± 1.41, and 73.80° ± 4.79, respectively. Regression analysis revealed that correlation between the contact angle of different surfaces and shear bond strength was not strong (P>.05). CONCLUSION. The retentive strength findings of all luting cements were higher in sandblasting and oxygen plasma groups than in control groups. Oxygen plasma treatment can improve the adhesion ability of titanium surfaces without any mechanical damage to titanium structure.

• Korean Chemical Engineering Research
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• 제50권3호
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• pp.421-426
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• 2012

불소계 아크릴레이트 2,2,2-trifluoroethylmethacrylate을 사용한 자외선 경화형 유-무기 하이브리드 코팅 막에 있어서 무기물 및 사용되는 유기 단량체의 종류 및 조성이 내 오존성 및 표면 특성에 미치는 영향에 대해 연구하였다. 코팅액은 금속 알콕사이드인 tetraethoxysilane(TEOS)와 실란 커플링제인 methacryloyloxypropyltrimethoxysilane(MPTMS)로 구성된 유-무기 혼성 용액에 2,2,2-trifluoroethylmethacrylate와 자외선 경화를 위한 유기물을 첨가하여 제조되었다. 코팅막은 코팅액을 기재위에 바 코팅 한 후 자외선 경화를 통해 제조되었다. 제조된 코팅 막의 내 오존성은 TEOS의 함량이 증가할수록 내 오존성과 표면경도는 향상되었다. 또한, 불소 함량이 증가할수록 내 오존성은 향상되었지만 표면 경도는 다소 떨어졌다. 우레탄 아크릴레이트를 첨가한 코팅 막은 높은 연필경도를 나타내었다. 코팅 막의 투과도는 TEOS와 2,2,2-trifluoroethylmethacrylate의 함량에 큰 영향을 받지 않았다. 더욱이, 코팅 막은 90% 이상의 높은 투과도를 나타내었다.

• 대한의생명과학회지
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• 제26권2호
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• pp.93-100
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• 2020

Xerostomia is a relatively common oral disease that causes various problems such as pain, discomforted, tissue damage, and infection. When the activity of AQPs, which plays an important role in the microbial channel transmembrane activity in tissues, decreases saliva secretion and the oral cavity dryness occurs. In this study, we observed whether there was a change in tissue through the expression level of AQP-5 in the submandibular gland in the 4-DAMP-induced xerostomia model. First, in order to construct a xerostomia model, 4-DAMP (1 mg/kg) and 20% urethane (0.5 mL/kg) were administered intraperitoneal (i.p.) to experimental animals. To observe the changes in the submandibular gland was excised, H&E staining was performed and protein quantitation analysis was performed using the submandibular tissue to observe the changes in AQP5 protein expression involved in changes in saliva secretion. Also, cinnamaldehyde (5, 12.5, 25 and 50 mg/kg) dissolved in 20% DMSO, in distilled water for each concentration, and then orally administered at a dose of 1 mL for biopsy and protein quantitative analysis. As a result, it was observed that the submandibular tissue, a model of xerostomia was wider than the naïve group. And then western blot analysis, the expression level of AQP5 decreased in the 4-DAMP group compared to the naïve group, and the expression increased in the group administered orally with cinnamaldehyde. Therefore, administration of 4-DAMP resulted in histological changes for xerostomia, and cinnamaldehyde would be a material that can be developed by reducing xerostomia.

• 대한기계학회논문집A
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• 제34권3호
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• pp.299-305
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• 2010

가변성형 공정에서 동일한 크기의 성형펀치 배열로 구성된 가변금형을 이용하는 경우 펀치의 크기가 일정하여 성형 가능한 곡률 반경이 제한되기 때문에 비교적 유연성이 낮다. 이에 본 연구에서는 가변금형의 유연성을 높이기 위하여 분할가변금형에 대한 개념을 제안하였다. 임의의 성형면을 형성하기 위하여 두 가지 크기의 펀치로 구성된 펀치 블록을 착안하였다. 상대적으로 큰 곡률 반경을 갖는 성형영역에 대해서는 크기가 큰 펀치 블록을 적용하였으며, 작은 곡률 반경을 갖는 성형영역에 대해서는 작은 크기의 펀치로 구성된 펀치 블록을 적용하였다. 해석적 연구를 토대로 성형된 제품의 단면 형상을 비교하였으며 이로부터 서로 다른 크기의 펀치 블록을 조합하여 구성한 분할가변금형을 이용한 판재의 성형공정이 비교적 복잡한 곡률 반경 분포를 갖는 곡면 가공에 적합함을 확인하였다.

• 약학회지
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• 제22권3호
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• pp.163-174
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• 1978

차전자(Plantaginis Semen)은 우리나라 전국 각지의 원야와 노방의 자생하는 다년생 초목으로 Plantaginaceae(질경이과)에 속하는 Plantago major L. var. asiatica Decaisne 질경이의 종자를 말하며 그의 성분으로는 다량의 점액, 지방유, pentosan 및 galactan, succinic acid, plantanolic acid, adenine, choline. K-염등이 알려져 있다. 이 차전자는 한방과 민간에서 소염, 이뇨, 진해, 지사제로서 널리 사용되어 왔으며 그의 약리작용에 관해서는 이미 저자들이 가토를 이용한 실험에서 이의 methanol extract가 자궁수축작용, 호흡흥분작용, 혈압강하작용, 장관수축작용, 심장박동의 완제작용, 항이뇨작용이 있음을 보고한 바 있다. 그러나 그의 기전에 관해서는 거의 알려진 바가 없다. 따라서 저자들은 위의 여러가지 작용중 특히 혈압강하작용에 관한 본태를 파악하여 그의 실용성 여부를 구명코자 이 실험을 착수하였다.

• 한국융합학회논문지
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• 제8권9호
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• pp.175-181
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• 2017

유방검사에서 영상의 진단 가치를 높일 수 있는 유방틀을 제작하여 유용성을 평가하고자 한다. 유리섬유강화플라스틱을 이용해서 유방틀을 제작하였다. 그리고 방사능계수율과 획득된 영상을 비교하였다. 유방틀의 평가에서 왼쪽과 오른쪽이 $1{\mu}Ci$ 당 counts가 각각 185 counts, 189 counts이다. 그리고 복와위 자세에서 획득된 영상은 원형에 가깝게 나타났다. 유방틀을 이용함으로써 진단 가치를 높일 수 있어 유방촬영 검사를 하는데 있어 유용할 것으로 사료된다.

• 한국환경과학회지
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• 제16권11호
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• pp.1225-1230
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• 2007

The emissions characteristics of particulate matters(PM) according to the types of wastes from industrial waste incinerator of 800 kg/hr treatment capacity were investigated. For this study, the incinerate waste are as follows; waste resin, waste wood, waste urethane, waste gunny, and waste paper. The particulate samples were collected to be emitted in stack and air pollution control(both cyclone and bag filter). In stack, the concentrations of PM were in the range of 2.61 to $26.51 mg/Sm^3$ and the major chemical species were C, Si, Cl, K, Na, Ca in all the wastes. In cyclone fly ash, the mean content of heavy metal were in the order of Fe > Zn > Pb > Cu > Mn > Cr > Ni > Cd > As > Hg and the heavy metal content of waste resin were Zn 34,197.5 mg/kg, Fe 27,587.6 mg/kg, Pb 6,055.8 mg/kg, respectively. In bag filter fly ash, the mean content of heavy metal were in the order of Zn > Pb > Fe > Cu > Mn > Cd > Cr > Ni > As > Hg and the heavy metal content of waste wood were Pb 36,405.2 mg/kg, Fe 15,762.9 mg/kg, Cu 9,989.5 mg/kg, Cd 2,230.1 mg/kg, respectively. Comparing the heavy metal content of both cyclone and bag filter, in cyclone, the Cr, Fe, Ni content were higher than in bag filter and the Cd, Cu, Hg content were lower than in bag filter.

• Korean Chemical Engineering Research
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• 제56권2호
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• pp.162-168
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• 2018

유기 및 무기 폴리실라잔을 우레탄 아크릴레이트와 혼합시킴에 따라 UV 경화형 하드 코팅 용액을 제조하였다. 이용액을 polymethylmethacrylate (PMMA) 시트에 흐름 코팅한 후 UV 경화시킴에 의해 UV 경화형 하드 코팅 도막을 제조하였다. 이 과정 중 폴리실라잔의 종류 및 첨가량을 변화시켜 코팅 도막의 물성에 미치는 영향을 살펴보았다. 그 결과 유기 폴리실라잔의 경우 $95^{\circ}$의 수접촉각을 보여 높은 소수성을 나타내었으며, 7H의 연필경도와 92%의 가시광선 투과율을 보였다. 반면에 무기 폴리실라잔을 코팅한 도막은 8H의 높은 연필경도와 기재와의 우수한 접착력 및 $82^{\circ}$의 수접촉각을 나타내었다.

• KIEAE Journal
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• 제16권4호
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• pp.41-46
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• 2016

Purpose: This is a study on the planning of temporary housing for post application of Mega Sports facilities. The subject of the study is 2018 Pyeongchang Winter Olympics, which is to suggest building an alternative temporary housing using shipping containers(high cube), which solve the lack of accommodations and recycle temporary housing after Olympics, save money and be eco-friendly in Olympics. Method: This study includes this ; research on the a fact-finding survey about Mega sports facilities post application and demand survey on 2018 Pyeongchang Winter Olympics accomodations and an analysis about temporary housing plan. Furthermore we decided temporary housing building plan by analyzing residents' needs and traits of the housing etc. Through this, we made a schematic design for household units. Result: As a result, this study is a plan of making space, forms, and structure. The planned size is $38.4m^2$(L:12m, W:3.2m) except balcony, and indoor height is 2.5m. The space consists of entrance, bathroom, bedroom and living room with folding furniture system. Also there's a detailed floor plan of the ceiling, wall, and floor we drew up. The ceiling and wall consist of dampproof film, noncombustible board, fire proof urethane form, and color-designed sheet. The floor is composed of floor tile, cement mortar, light concrete(with heat coil), insulation, and dampproof film. Additionally, this study is a plan of interior dry wall with detail using modular construction method for work efficiency and quality improvement.

• Restorative Dentistry and Endodontics
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• 제45권3호
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• pp.32.1-32.12
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• 2020

Objectives: To evaluate the polymerization efficiency of a matrix-modified bulk-fill composite, and compare it to a conventional composite which has a similar filler system. The degree of conversion (DC%) and monomer elution were measured over different storage periods. Additionally, fillers' content was examined. Materials and Methods: Cylindrical specimens were prepared, in bulk and incrementally, from Filtek Bulk Fill (B) and Filtek Supreme XTE (S) composites using a Teflon mold, for each test (n = 6). Using attenuated total reflection method of Fourier transformation infrared spectroscopy, DC% was measured after 24 hours, 7 days, and 30 days. Using high-performance liquid chromatography, elution of hydroxyethyl methacrylate, triethylene glycol dimethacrylate, urethane dimethacrylate, and bisphenol-A glycidyl dimethacrylate was measured after 24 hours, 7 days and 30 days. Filler content was examined by scanning electron microscopy (SEM). Data were analyzed using 2-way mixed-model analysis of variance (α = 0.05). Results: There was no significant difference in DC% over different storage periods between B-bulk and S-incremental. Higher monomer elution was detected significantly from S than B. The elution quantity and rate varied significantly over storage periods and between different monomers. SEM images showed differences in fillers' sizes and agglomeration between both materials. Conclusions: Matrix-modified bulk-fill composites could be packed and cured in bulk with polymerization efficiency similar to conventional composites.