• The Journal of Korean Academy of Prosthodontics
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• v.35 no.4
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• pp.647-661
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• 1997

The resin modified glass ionomer cements(RMGICs) have been used for years since 1989. Recently it has been developed for luting of fixed restorations. To evaluate the bond strength and marginal leakage of RMGICs for luting usage, the 80 extracted human molars which had uniform area of exposed dentin were cemented with 3 types of RMGICs(Fuji Duet, Advance, Vitremer), a conventional Glass Ionomer Cement(GIC-Fuji I), and a resin cement (Panavia 21) to base metal alloy(Ni-Cr-Be). After thermocycling the specimens were immersed in basic fuschin dye for measuring marginal leakage. The shear bond strength was measured with Instron and the maximum dye penetration was measured to 0.1mm. The types of fractured patterns were determined with stereoscope(${\times}7.5$). The results are as follows. 1. The difference between 3 RMGICs and a conventional GIC in shear bond strength was not statistically significant. It seemed that RMGICs had lower shear bond strength than resin cement. (p<0.01) 2. The mean scores of marginal leakage had no significant difference between the resin cement and 3 RMGICs but it was much higher in conventional GIC than the RMGICs (p<0.05) 3. It was determined that the manufacturer and the methods of dentin pretreatment determined the pattern of fracture surfaces and the frequency of adhesive failure between teeth and 3 RMGICs standed as in following order - Vitremer, Advance, Fuji Duet. (p<0. 01) When the fracture pattern was analyzed, it could be said that the materials and the method of dentin pretreatment have much effect on bonding states. This means that the dentin bonding agents should be improved. But the limited products in this experiment can not evaluate the physical properties of the entire RMGICs. Therefore a further study which can evaluate various RMGICs should be in progress to develope better cements.

• The Journal of Pediatrics of Korean Medicine
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• v.24 no.2
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• pp.40-48
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• 2010

Objectives The purpose of this study is to get the basic information about the actual amount of consumption of the Health supplements and Herbal Medicines. Also, we investigated the consumption differences according to the regions. Methods 500 questionnaires were handed out to parents of elementary students in O O, Gyeonggi-do province, and 331 questionnaires were collected and evaluated for this study. Results Among the 331 students, 58.4% were female, and 41.6% were male. The percentages of the subjects consuming health supplements and herbal medicines were 67.4% and 59.2% respectively. The maximum period of taking the health supplements were from 1 month to 6 month (49.5%), and the maximum period of taking the herbal medicine was within one month (55.6%). The total cost of the health supplements was less than 100,000won (43.7%), which was the most common while herbal medicine cost was between 100,000won and 200,000won (40.6%). The most common age of consuming the health supplements and herbal medicine for the first time was six to ten years old (47.3%); the case of herbal medicine was one to six years old (64.0%). Most of people purchased health supplements from pharmacy (48.0%), and purchased the herbal medicine from the oriental medical clinic (61.8%). Among those people who purchased health supplements, they bought nutritional supplements (82.8%), red ginseng or ginseng products (43.4%), plum extract products (10.9%), and chlorella products (6.8%). The reason for consuming health supplements was to be healthier even though there is no ongoing illness (47.1%), which was the most common reason. The reason for consuming herbal medicine was to cure weakness (39.3%). For the responses about effectiveness after taking medications, people thought herbal medicine seemed to be more effective compare to health supplements (72.3%, 63% respectively). Only 1.4% of the subjects consuming the health supplements showed adverse effects while herbal medicine showed 4.6%. The most common adverse effects were 'general reaction' caused by the health supplements and dermatologic problems caused by the herbal medications. Conclusions Among 331 subjects, the percentage of consuming the health supplements (67.4%) was higher than the Herbal Medicine (59.2%). The total consuming cost of the herbal medications was higher than general health supplements. Also, the maximum period of consuming the health supplements was longer than herbal medications. Therefore, it is shown that herbal medications have no price competitiveness compare to health supplements. The age of using the herbal medicine for the first time was younger than the health supplements. Even though many people can purchase both health supplements and herbal medication from pharmacies and local oriental medical clinic, it is also shown that some people thought that the health supplements should be purchased from oriental medical hospital (13.9%). The most commonly taken forms of the health supplement was nutrition-supplying products, and the second common health supplements were ginseng and red ginseng. The health supplements were commonly consumed for preventing illness and for maintaining healthy life rather than for cure diseases. On the other hand, the herbal medicine was more commonly consumed to be taller or to treat diseases. More than half of the entire people replied as 'satisfied' for their purchase. Some adverse effects and general reaction were common with the subjects consuming health supplements while dermatological adverse reaction was common with the subjects consuming herbal medications.

• Composites Research
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• v.12 no.4
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• pp.71-78
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• 1999

To determine the effect of chemical structure of linear amine curing agents on thermal and mechanical properties, standard epoxy resin DGEBA was cured with diaminodiphenyl methane (DDM), diaminodiphenyl sulphone (DDS) in a stoichiometrically equivalent ratio. From this work, the effect of aromatic amine curing agents. In contrast, the results show that the DGEBA/DDS cure system having the sulfone structure between the benzene rings had higher values in the conversion of epoxide, density, shrinkage (%), glass transition temperature, tensile modulus and strength, flexural modulus and strength than the DGEBA/DDM cure system having methylene structure between the benzene rings, whereas the DGEBA/DDM cure system presented higher values in the maximum exothermic temperature, thermal expansion coefficient, and thermal stability. These results are caused by the relative effects of sulfone group having strong electronegativity and methylene group having (+) repulsive property and stem from the effect of the conversion ratio of epoxide group. The result of fractography shows that the each grain size of the DDM/DGEBA system with feather-like structure is larger than that of the DDS/DGEBA system.

• Macromolecular Research
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• v.17 no.10
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• pp.776-784
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• 2009

N,N-dimethyldodecylamine (tertiary amine)-modified MMT (DDA-MMT) was prepared as an organically modified layered silicate (OLS), after which styrene-butadiene rubber (SBR) nanocomposites reinforced with the OLS were manufactured via the latex method. The layer distance of the OLS and the morphology of the nanocomposites were characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM). By increasing the amount of N,N-dimethyldodecylamine (DDA) up to 2.5 g, the maximum values of torque, tensile strength and wear resistance of the SBR nanocomposites were increased due to the increased dispersion of the silicate layers in the rubber matrix and the increased crosslinking of the SBR nanocomposites by DDA itself. When SBR nanocomposites were manufactured by using the ternary filler system (carbon black/silica/OLS) to improve their dynamic properties as a tire tread compound, the tan $\delta$(at $0^{\circ}C$ and $60^{\circ}C$) property of the compounds was improved by using metal stearates instead of stearic acid. The mechanical properties and wear resistance were increased by direct substitution of calcium stearate for stearic acid because the filler-rubber interaction was increased by the strong ionic effect between the calcium cation and silicates with anionic surface. However, as the amount of calcium stearate was further increased above 0.5 phr, the mechanical properties and wear resistance were degraded due to the lubrication effect of the excessive amount of calcium stearate. Consequently, the SBR/organoclay nanocomposites that used carbon black, silica, and organoclay as their ternary filler system showed excellent dynamic properties, mechanical properties and wear resistance as a tire tread compound for passenger cars when 0.5 phr of calcium stearate was substituted for the conventionally used stearic acid.

• Polymer(Korea)
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• v.27 no.3
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• pp.183-188
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• 2003

The dielectric constants of fluorine-containing epoxy resins, 2-diglycidylether of benzotrifluoride(FER)/4,4'-diamino-diphenyl methane (DDM) and diglycidylether of bisphenol-A (DGEBA)/DDM systems were evaluated by dielectric spectrometer. Glass transition temperature and thermal stability factors, including initial decomposed temperature, temperatures of maximum rate of degradation, and decomposition activation energy of the cured specimens were investigated by dynamic mechanical analysis and thermogravimetric analysis. For the mechanical properties of the casting specimens, the fracture toughness, flexural, and impact tests were performed, and their fractured surfaces were examined by scanning electron microscope. The dielectric constant of FER/DDM system was lower than that of commercial DGEBA/DDM system, and the mechanical properties of the cured specimens showed higher values than those of DGEBA/DDM system. This was probably due to the introduction of trifluoromethyl (CF$_3$) group into the side chain of the epoxy resins, resulting in improving the electric and mechanical properties of the epoxy cure system studied.

• Journal of Korean Medical classics
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• v.26 no.4
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• pp.291-304
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• 2013

Objective : Jangjinyopyeon(藏珍要編, JJYP) was published in 1894. The purpose of the research is to know the character of JJYP, and to know JJYP inherited the tradition of Chosun(朝鮮) acupuncture which put emphasis on diagnosis and cure of Jangbu(臟腑) through meridian system. Method : First, identify the bibliographic information of the Mimeograph version of Original JJYP. After then, count and classify the provision by selected acupoints. Analyzed the result in succession. Conclusion : From the research of the mimeograph version of Original JJYP, come to following conclusion. 1. The pen name of author is Songgye(松溪), which means the region of his origin. 2. JJYP used 49 acupoints in total. It covers all regular meridian system except the regular Meridian of Hand Soeum[手少陰心經] for heart organ would never be injured in Neijing(內經) 3. JJYP suggested Eight Confluent points[八脈交會穴] as major acupoints in the end of book. But actually they were selected as the acupoints of belonging Jangbu(臟腑) and various symtoms. 4. Oegwan(外關) and Sameumgyo(三陰交) were maximum frequency in selecting of all acupoints, which means JJYP value controling and covering whole body. 5. Generally, Reinforcing and reducing manipulations concentrated one way, but Hugye(後谿) used each manipulation equally, which means JJYP regards tonification or purgation highly in Hugye(後谿). 6. Most acupoints of high frequency were Nak-point[絡穴], Won-point[原穴], Hap-point[合穴], which supposed to be directly connected to Jangbu(臟腑). So, we can see JJYP continue the tradition of Chosun acupuncture which put emphasis on Jang image[藏象] of meridian.

• The Journal of Korean Medicine
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• v.35 no.1
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• pp.114-123
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• 2014

Objectives: Evidence-based medicine(EBM) advocates the use of up-to-date "best" scientific evidence from health care research as the basis for making medical decisions. EBM also has been applied to traditional Korean medicine(TKM), especially in the field of safety. Recently, the standard prescription for TKM by Korea Institute of Oriental Medicine was published based on toxic index from various toxicity tests. However, there are some limitations when the results from the study based on EBM are applied in clinics. To overcome these imitations, the term "evidence-based practical medicine" was developed and defined as clinically applicable results from the study based on EBM. And safety classification for TKM was suggested as an example of evidence-based practical medicine. Methods: For safety classification for TKM, the data for $LD_{50}$(50% lethal dose), which was transformed to theoretical $LD_1$(1% lethal dose), was analyzed as one of tools for EMB study and divided by maximum dose used in clinics. Results and Conclusions: As a result, human equivalent dose(HED)-based MOS(margin of safety) for korean traditional medicine was calculated and used for safety classification with 5 categories. These categories would be helpful for oriental medicine clinicians to decide the increase and decrease of dosage according to various factors such as patient's sensitivity, potential toxicity of herbal medicines, clinician's experience for better cure. Thus, this safety classification provides some evidences enough that evidence-based practical medicine should be not the same with EBM and defined differently from EBM.

• Journal of Pharmacopuncture
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• v.21 no.3
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• pp.159-167
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• 2018

Objectives: Myocardial reperfusion is the only logical cure for ischemic heart disease. However, ischemic-reperfusion (I/R) injury is one of the underlying factors facilitating and accelerating the apoptosis in the myocardium. This study set to investigate the impact of Teucrium polium (TP) hydro-alcoholic extract on I/R induced apoptosis in the isolated rat heart. Methods: Isolated rat hearts were classified into six groups. The control samples were subjected to 80 min of perfusion with Krebs-Henseleit bicarbonate (KHB) buffer; in control-ischemia group, after primary perfusion (20 min) the hearts were exposed to global ischemia (20 min) and reperfusion (40 min). Pretreated groups were perfused with $500{\mu}M$ of vitamin C and various TP concentrations (0.5, 1, 2 mg/ml) for 20 min, and then the hearts were exposed to ischemia and reperfusion for 20 min and 40 min, respectively. Cardiodynamic parameters including rate pressure product (RPP), heart rate (HR), the maximum up/down rate of left ventricular pressure (${\pm}dp/dt$), left ventricular developed pressure (LVDP), and coronary artery flow (CF) were achieved from Lab Chart software data. The Bax and BCl-2 gene expressions were measured in heart samples. Results: Hearts treated with TP extract and vit C represented a meaningful improvement in cardiac contractile function and CF. The overexpression of Bcl-2, downregulation of Bax, and improvement of apoptotic index (Bax/Bcl-2) were observed in pretreated TP extract and vit C hearts. Conclusion: The TP extract was found to ameliorate the cardiac function in the reperfused myocardium. Also, it can hinder apoptotic pathways causing cardioprotection.

• Elastomers and Composites
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• v.45 no.3
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• pp.223-229
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• 2010

We investigated the effects of processing geometry of silica-filled isobutylene-isoprene rubber (IIR) compounds on its mechanical properties and silica dispersion, using a two roll mill and an internal mixer (banbury mixer). The compound processed with the two roll mill showed the longer induction time ($t_2$), higher maximum torque ($T_{max}$), and better silica dispersion than the compound processed with the internal mixer; however, showed slightly the lower cure index ($t_{90}$). The mechanical properties (hardness, 300% modulus, tensile strength, elongation) of the compound processed with two roll mill were higher than compound done with the internal mixer.

• Polymer(Korea)
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• v.35 no.4
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• pp.342-349
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• 2011

The effect of the amount of vinyltriethoxysilane (VTEOS) in precipitated silica filled silicone rubbers was extensively investigated in terms of the change of mechanical properties, heat resistance, oil resistance, compression set, resilience, and curing characteristics. As the content of VTEOS increased from 0 to 2.0 phr, the hardness of the silicone rubber increased, however, tensile strength, elongation at break, and tear strength decreased. From heat resistance test, the change of mechanical properties was pronounced for silicone rubber treated with more VTOES. The best heat resistance was achieved at 2.0 phr VTOES. In addition, oil resistance was proportionally improved with VTEOS content. From oil resistance test. it was found that the decrease in hardness and maximum elongation was reduced for VTEOS-added systems. Finally, resilience, compression set, degree of cure and crosslink density were significantly enhanced with the amount of VTEOS.