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Dislodgement resistance of modified resin-bonded fixed partial dentures utilizing tooth undercuts: an in vitro study

  • Doh, Re-Mee;Lee, Keun-Woo
    • The Journal of Advanced Prosthodontics
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    • v.1 no.2
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    • pp.85-90
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    • 2009
  • STATEMENT OF PROBLEM. Over the years, resin-bonded fixed partial dentures (RBFPDs) have gone through substantial development and refinement. Several studies examined the biomechanics of tooth preparation and framework design in relation to the success rate of RBFPDs and considered retention and resistance form essential for increase of clinical retention. However, these criteria required preparations to be more invasive, which violates not only the original intentions of the RBFPD, but may also have an adverse effect on retention due to loss of enamel, an important factor in bonding. PURPOSE. The object of this in vitro study was to compare the dislodgement resistance of the new types of RBFPDs, the conventional three-unit fixed partial denture, and conventional design of RBFPD (Maryland bridge). MATERIAL AND METHODS. Fifty resin mandibular left second premolars and second molars were prepared on dentiforms, according to the RBFPD design. After model fabrication (five group, n = 10), prostheses were fabricated and cemented with zinc phosphate cement. After cementation, the specimens were subjected to tensile loading at a cross head speed of 4 mm/min in a universal testing machine. The separation load was recorded and analyzed statistically using one-way analysis of variance followed by Duncan's multiple range test. RESULTS. Group V, the pin-retained RBFPDs, had the highest mean dislodgement resistance, whereas specimens of group II, the conventional RBFPDs, exhibited a significantly lower mean dislodgement resistance compared to the other 4 groups (P <.05). There were no significant differences between group I, III, and IV in terms of dislodgement resistance (P>.05). Group V had the highest mean MPa (N/$mm^2$) (P <.05). There was no significant difference between groups I, II, III and IV (P > .05). CONCLUSION. Within the limits of the design of this in vitro study, it was concluded that: 1. The modified RBFPDs which utilizes the original tooth undercuts and requires no tooth preparation, compared with the conventional design of RBFPDs, has significantly high dislodgement resistance (P < .05). 2. The modified RBFPDs which utilizes the original tooth undercuts and requires minimal tooth preparation, compared with the conventional FPDs, has significantly no difference in retention and dislodgement resistance)(P>.05). 3. The pin-retained FPDs showed a high dislodgement resistance compared to the conventional three-unit FPDs (P<.05).

Heavy Metals Contens and Organochlorine Pestieide Residues in Commercial Salted and Fermented Sea Foods (시판 젓갈중의 중금속 및 유기염소 잔유농약의 함량)

  • Ryu, Beung-Ho;Ha, Mi-Suck;Kim, Dong-Seuk;Sin, Dong-Bun;Hur, Ho-Jang;Jung, Jong-Soon
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.15 no.3
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    • pp.207-212
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    • 1986
  • Heavy metal contents and residues level of organochlorine pesticides were analyzed for commercial salted and fermented sea-food which bought from pusan area. Heavy metal contents ranged from 0.11 to 0.46 ppm of mercury, trace to 1.1 ppm of lead, 0.01 to 0.34 ppm of cadmium, 0.4 to 5.98 ppm of cupper, 0.16 to 4.5 ppm of zinc, trace to 0.49 ppm of manganese and trace to 1.35 ppm of arsenic. Residue level of organochlorine pesticides in salted and fermented sea-foods ranged from 0.3 ppb to 1.825 ppb of total BHC Organochlorine pesticides of DDE, dieldrine, pp'-DDD and pp'-DDT were detected a small amount from Ge jeot and Myeol-Chi jeot. In conclusion. the heavy metal and levels of organochlorine pesticides residues were safety to eat the salted and fermented sea foods.

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Effect of ZnCl2 Co-catalyst in the Synthesis of Dimethyl Carbonate from Ethylene Carbonate and Methanol by Using Base Catalysts (염기 촉매를 이용한 디메틸카보네이트 합성에서 ZnCl2 조촉매의 영향)

  • Kim, Dong-Woo;Park, Moon-Seok;Kim, Moon-Il;Park, Dae-Won
    • Korean Chemical Engineering Research
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    • v.50 no.2
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    • pp.217-222
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    • 2012
  • The synthesis of dimethyl carbonate(DMC) is a promising reaction for the use of naturally abundant carbon dioxide. DMC has gained considerable interest owing to its versatile chemical reactivity and unique properties such as high oxygen content, low toxicity, and excellent biodegradability. In this study, the synthesis of DMC through the transesterification of ethylene carbonate(EC) with methanol was investigated by using ionic liquid and metal oxide catalysts. The screening test of different catalysts revealed that choline hydroxide ([Choline][OH]) and 1-n-butyl-3-methyl imidazolium hydroxide([BMIm][OH]) had better catalytic performance than metal salts catalysts such as MgO, ZnO and CaO. The effects of reaction parameters such as reaction temperature, MeOH/EC mole ratio, and carbon dioxide pressure on the reactivity of [Choline][OH] catalyst were discussed. High temperature and high MeOH/EC mole ratio were favorable for high conversion of EC. However, the yield of DMC showed a maximum when carbon dioxide pressure was 1.34 MPa, and then it decreased for higher carbon dioxide pressure. Zinc chloride($ZnCl_2$) was used as co-catalyst with the ionic liquid catalyst. The mixed catalyst showed a synergy effect on the EC conversion and DMC yield probably due to the acid-base properties of the catalysts.

Comparative Evaluation of Dietary Intake Status on Self-selected Diet in Korean Adults by Region Groups (성인의 일상적인 식사섭취상태의 지역별 비교평가)

  • Choe, Mi-Gyeong;Lee, Ju-Yeon;Lee, Won-Yeong;Park, Jeong-Deok
    • Journal of the Korean Dietetic Association
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    • v.11 no.3
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    • pp.309-319
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    • 2005
  • The purpose of this study was to compare the nutritional menu value of self-selected diet in Korean adults residing in different regions. Subjects were recruited and divided into three groups according to the districts where they lived, which included rural district(n=137), coastal district(n=100), and urban district(n=117). Subjects were interviewed using a general questionnaire and 24-hour recall method for dietary intake. The average age of the subjects were 57.5 years for rural district, 57.0 years for coastal district, and 47.9 years for urban district. The contents of energy, calcium, zinc, vitamin $B_2$, and vitamin E in self-selected diet were 76.1%, 60.1%, 73.1%, 68.6%, and 80.4% of RDAs, respectively. Index of nutritional quality(INQ) for calcium and vitamin $B_2$ was below in 1 in region groups. The contents of calcium and vitamin E in self-selected diet of rural and coastal districts were significantly lower than those of urban district. The numbers of food items in diet of rural, coastal, and urban district were 14.6, 15.3, 15.1 for breakfast, 16.5, 11.8, 17.0 for lunch, 14.9, 12.1, 15.1 for dinner, respectively. However, there was no significance in total food intake by regions. The food intakes from cereals, mushrooms, vegetables of rural district, that from fishes of coastal district, and those from sugars, milks, oils of urban district were the highest among three districts. The numbers of dish items in diet of rural, coastal, and urban district were 4.1, 4.4, 4.1 for breakfast, 4.5, 3.7, 4.4 for lunch, 4.0, 3.8, 4.2 for dinner, respectively. Especially, the number of food and dish items in lunch menu of coastal district was the lowest among region groups. According to these results, it could be suggested to add milk and its products in lunch menu of rural and coastal districts and to supplement fish and shellfish like anchovy in diet of rural and urban districts. And it is recommended to increase food and dish items in diets of three region groups.

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Assessment of Diet Quality by Weight Status and Its Association with Obesity in Children and Adolescents (소아청소년 체중상태에 따른 식사의 질 평가 및 비만과의 연관성 분석)

  • Yang, See-Won;Lee, Hyang-Suk;Kim, JiEun;Kim, YoonMyung;Seo, Young-Gyun;Park, Kyung Hee;Jang, Han Byul;Lee, Hye-Ja;Park, Sang Ick;Lim, Hyunjung
    • Journal of the Korean Dietetic Association
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    • v.23 no.3
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    • pp.263-273
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    • 2017
  • Numerous studies have investigated quantifying dietary intake according to the weight status of children and adolescents. However, studies on differences in quality among diets remain scarce. This study compared diet quality by weight status and examined correlations between quality of diet and obesity in children and adolescents. Two hundred fourteen children and adolescents aged between 9 and 18 years participated in this study (Normal weight n=104, Obesity n=110). The data related to food intake were investigated by dietary records, Diet Quality Index-International (DQI-I), and Nutrition Quotient (NQ) and then compared with Dietary Reference Intakes for Korean (KDRIs). In DQI-I, moderation factor (control of unhealthy foods) score was 21.7 in the normal weight group and 19.5 in the obesity group. The normal weight group showed a higher score for moderation factor than the obesity group (P<0.001). Compared with KDRIs, vitamin $B_6$, folate, vitamin C, vitamin E, calcium, potassium, and zinc intakes were insufficient in both groups. Multiple logistic regression analysis revealed that DQI-I moderation was negatively associated with obesity (OR=0.77, 95% CI 0.69-0.87) after adjustment for age, gender, income, and total energy intake. Our results suggest that children and adolescents require nutritional education to understand the importance of vitamin and mineral consumption. Especially, education for children and adolescents with obesity needs to emphasize moderation of nutrient intake that can cause diseases with hyper-ingestion such as sodium and high calorie-low nutrition foods.

Transcription factor EGR-1 transactivates the MMP1 gene promoter in response to TNFα in HaCaT keratinocytes

  • Yeo, Hyunjin;Lee, Jeong Yeon;Kim, JuHwan;Ahn, Sung Shin;Jeong, Jeong You;Choi, Ji Hye;Lee, Young Han;Shin, Soon Young
    • BMB Reports
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    • v.53 no.6
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    • pp.323-328
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    • 2020
  • Matrix metalloproteinase 1 (MMP-1), a calcium-dependent zinccontaining collagenase, is involved in the initial degradation of native fibrillar collagen. Tissue necrosis factor-alpha (TNFα) is a pro-inflammatory cytokine that is rapidly produced by dermal fibroblasts, monocytes/macrophages, and keratinocytes and regulates inflammation and damaged-tissue remodeling. MMP-1 is induced by TNFα and plays a critical role in tissue remodeling and skin aging processes. However, the regulation of the MMP1 gene by TNFα is not fully understood. We aimed to find additional cis-acting elements involved in the regulation of TNFα-induced MMP1 gene transcription in addition to the nuclear factor-kappa B (NF-κB) and activator protein 1 (AP1) sites. Assessments of the 5'-regulatory region of the MMP1 gene, using a series of deletion constructs, revealed the requirement of the early growth response protein 1 (EGR-1)-binding sequence (EBS) in the proximal region for proper transcription by TNFα. Ectopic expression of EGR-1, a zinc-finger transcription factor that binds to G-C rich sequences, stimulated MMP1 promoter activity. The silencing of EGR-1 by RNA interference reduced TNFα-induced MMP-1 expression. EGR-1 directly binds to the proximal region and transactivates the MMP1 gene promoter. Mutation of the EBS within the MMP1 promoter abolished EGR-1-mediated MMP-1 promoter activation. These data suggest that EGR-1 is required for TNFα-induced MMP1 transcriptional activation. In addition, we found that all three MAPKs, ERK1/2, JNK, and p38 kinase, mediate TNFα-induced MMP-1 expression via EGR-1 upregulation. These results suggest that EGR-1 may represent a good target for the development of pharmaceutical agents to reduce inflammation-induced MMP-1 expression.

Population and transfer factor of basidiomycota collected in the heavy metal-contaminated and healthy soils (중금속 오염지 및 건전지역에서 수집된 담자균류의 분포)

  • Jang, Kab-Yeul;Choi, Sun-Gyu;Lee, Kang-Hyo;Seok, Soon-Ja;Cheong, Jong-Chun;Jung, Gu-Bok;Kim, Gyu-Hyun;Sung, Jae-Mo
    • Journal of Mushroom
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    • v.3 no.4
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    • pp.145-153
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    • 2005
  • Two hundred seventy-four microorganisms were isolated from the soil of abandoned mines around for selecting the heavy metal-degrading strains and their microbial diversity was analyzed. The specimens of macrofungi were isolated from the soil of abandoned mines around for selecting the heavy metal-degrading strains. Eunseong and Dogok in Gyeongsangbuk-do, for selecting the heavy metal-degrading strains. Soil was also collected from same location. Contents of heavy metals (Cd, Cu, Pb, Zn, Ni, Cr, and As) were determined spectrometically in fruiting bodies of forty eight wild macrofungi specimens with soils. When the analysed their transfer factor from soil to fruiting body, Amanita volvata have the highest transfer factor of cadmium and arsenic. And Mycena pura showed the highest in mercury, Marasmius pulcherripes in zinc, Laccaria laccata in nickel, and Collybia confluens in chrome. When compare the population of mushrooms between the contaminated mines and Mt. Chiak as the healthy area, Genus Russula and Collybia were collected both area, but Leucocoprinus, Coprinus, Suillus, Lepiost, Gyroporus, Lepista, Microstoma, Stropharia, and Agrocybe were only in the contaminated mine area.

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Mechanical Properties of Natural Rubber/Acrylonitrile-Butadiene Rubber Blends and Their Adhesion Behavior with Steel Cords (Natural Rubber/Acrylonitrile-Butadiene Rubber 블렌드의 기계적 물성과 강선과의 접착거동)

  • Sohn, Bong-Young;Nah, Chong-Woon
    • Elastomers and Composites
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    • v.36 no.2
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    • pp.111-120
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    • 2001
  • Mechanical properties and their adhesion behavior with zinc- and brass-plated steel cords of natural rubber/acrylonitrile-butadiene blend compounds were investigated as a function of blend ratio. The Mooney viscosity and stress relaxation time were found to be lowered with increasing NBR content. Tensile modulus generally increased with increasing NBR content. Tensile stress at break stayed constant up to about 40 phr and showed minimum at $50{\sim}60 phr$, and thereafter increased with increasing NBR content. Strain at break decreased linearly below 50 phr, and above the level it showed nearly constant value. Based on the abrupt drops in elastic modulus and tan ${\delta}$ peak, the glass transition temperature of NR and NBR were found to be -55 and $-10^{\circ}C$, respectively. In the case of NR/NBR blend compounds, two distinct transition points were observed and each transition position was not affected by NBR level indicating an incompatible nature of NR/NBR blend system. The pullout force and rubber coverage decreased to the level of about 40% to that of pure m compound, when the 50 phr of NR was replaced by NBR. However, the pure NBR compound showed the comparable adhesion performance with NR(${\sim}90%$). The sulfur concentration was found to become lower with the increased NBR content at the adhesion interface based on the Auger spectrometer results, representing a lack of adhesion layer formation, and this was explained for a possible cause of low adhesion performance with adding NBR.

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The Study of Plate Powder Coated Nano Sized ZnO Synthesis and Effect of Sensory Texture Improvement (나노 ZnO 입자가 코팅된 판상 분체의 합성과 사용감 증진 효과에 대한 연구)

  • Jin-Hwa , Lee;Ju-Yeol, Han;Sang-Gil, Lee;Hyeong-Bae, Pyo;Dong-Kyu, Lee
    • Journal of the Society of Cosmetic Scientists of Korea
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    • v.30 no.2
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    • pp.173-180
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    • 2004
  • Nano sized ZnO particle as 20-30nm applies for material, pigments, rubber additives, gas sensors, varistors, fluorescent substance as well as new material such as photo-catalyst, sensitizer, fluorescent material. ZnO with a particle size in the range 20-30nm has provided to be an excellent UV blocking material in the cosmetics industry, which can be used in sunscreen product to enhance the sun protection factor and natural makeup effect. But pure ZnO particles application limits for getting worse wearing feeling. We make high-functional inorganic-composite that coated with nano-ZnO on the plate-type particle such as sericite, boron nitride and bismuthoxychloride. In this experiment, we synthesized composite powder using hydrothermal precipitation method. The starting material was ZnCl$_2$ Precipitation materials were used hexamethylenetetramine(HMT) and urea. We make an experiment with changing as synthesis factors that are concentrations of starting material, precipitation materials, nuclear formation material, reaction time, and reaction temperature. We analyzed composite powder's shape, crystallization and UV-blocking ability with FE-SEM, XRD, FT-IR, TGA-DTA, In vitro SPF test. The user test was conducted by product's formulator. In the results of this study, nanometer sized ZnD was coated regardless of the type of plate-powder at fixed condition range. When the coated plate-powders were applied in pressed powder product, the glaze of powder itself decreased, but natural make-up effect, spreadability, and adhesionability were increased.

The Stabilization of 20.0% Ascorbic Acid in Aqueous Cosmetic Formulation (아스코빅애씨드 고함량 안정화 수계 조성물 제조 방법)

  • Park, Jeong Mi;Eun, So Hee;Ko, Eun Ah;Han, Sang Keun;Kang, Hak Hee;Hyun, Seung Min
    • Journal of the Society of Cosmetic Scientists of Korea
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    • v.44 no.2
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    • pp.125-131
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    • 2018
  • Ascorbic acid (Vitamin C) has been widely used in skin care formulations. Due to its remarkable effects on anti-oxidation, collagen biosynthesis and whitening, ascorbic acid is considered as an effectible anti-aging active ingredient. But, the instability problems of ascorbic acid in cosmetic formulation such as oxidation, browning and changes in smell is the difficult issue to be overcome for the application of high concentration of ascorbic acid. We tried to stabilize the ascorbic acid in non-aqueous liquid formulation that contains polyol solvent at first. The non-aqueous system was effectible to reduce oxidation. But, ascorbic acid was crystallized in the non-aqueous formulation at the low temperature below $5^{\circ}C$. We tried to develop way to stabilize the ascorbic acid in aqueous solutions to solve the crystallizing problem. In this study, we search the optimal ratio of antioxidant combination, such as zinc sulfate, glutathione and curcuma longa (turmeric) root extract. Formulations were stored at - $16^{\circ}C$, $5^{\circ}C$, $25^{\circ}C$, $40^{\circ}C$, $50^{\circ}C$ and cycle($5-40^{\circ}C$) (in incubator) for a period of eight weeks to investigate their stability. In the stability analysis, the test parameters consisted of color, scent, phase separation and sedimentation. Ascorbic acid stability was checked by HPLC analysis.