• The Journal of Korean Academy of Prosthodontics
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• v.47 no.1
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• pp.61-69
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• 2009

Statement of problem: Porcelain veneers have become a popular treatment modality for aesthetic anterior prosthesis. Fitting porcelain veneers in the mouth usually involve a try-in appointment, which frequently results in salivary contamination of fitting surfaces. Purpose: An in vitro study was carried out to investigate the effect of silane treatment timing and saliva contamination on the resin bond strength to porcelain veneer surface. Material and methods: Cylindrical test specimens (n=360) and rectangular test specimens (n=5) were prepared for shear bond test and contact angle analysis. Whole cylindrical specimens divided into 20 groups, each of which received a different surface treatment and/or storage condition. The composite resin cement stubs were light-polymerized onto porcelain adherends. The shear bond strengths of cemented stubs were measured after dry storage and thermocycling (3,000 cycles) between 5 and $55^{\circ}C$. The silane and their reactions were chemically monitored by using Fourier Transform Infrared Spectroscopy analysis (FTIR) and contact angle analysis. One-way analysis of variance (ANOVA) and Dunnett's multiple comparison were used to analyze the data. Results: FT-IR analysis showed that salivary contamination and silane treatment timing did not affect the surface interactions of silane. Observed water contact angles were lower on the saliva contaminated porcelain surface and the addition of 37% phosphoric acid for 20 seconds on saliva contaminated porcelain increased the degree of contact angle. Silane applied to the porcelain, a few days before cementation, resulted in increasing the bond strength after thermocycling. Conclusion: Within the limitation of this study, it can be concluded that it would be better to protect porcelain prosthesis before saliva contamination with silane treatment and to clean the contaminated surface by use of phosphoric acid.

• The Journal of Korean Academy of Prosthodontics
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• v.50 no.3
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• pp.156-161
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• 2012

Purpose: This study was conducted to obtain difference in fracture strength according to the diameter of one-body O-ring-type of mini implant fixture, to determine the resistance of mini implant to masticatory pressure, and to examine whether overdenture using O-ring type mini implant is clinically usable to maxillary and mandibular edentulous patients. Materials and methods: For this study, 13 mm long one body O-ring-type mini implants of different diameters (2.0 mm, 2.5 mm and 3.0 mm) (Dentis, Daegu, Korea) were prepared, 5 for each diameter. The sample was placed at $30^{\circ}$ from the horizontal surface on the universal testing machine, and off-axis loading was applied until permanent deformation occurred and the load was taken as maximum compressive strength. The mean value of the 5 samples was calculated, and the compressive strength of implant fixture was compared according to diameter. In addition, we prepared 3 samples for each diameter, and applied loading equal to 80%, 60% and 40% of the compressive strength until fracture occurred. Then, we measured the cycle number on fracture and analyzed fatigue fracture for each diameter. Additionally, we measured the cycle number on fracture that occurred when a load of 43 N, which is the average masticatory force of complete denture, was applied. The difference on compressive strength between each group was tested statistically using one-way ANOVA test. Results: Compressive strength according to the diameter of mini implant was $101.5{\pm}14.6N$, $149{\pm}6.1N$ and $276.0{\pm}13.4N$, respectively, for diameters 2.0 mm, 2.5 mm and 3.0 mm. In the results of fatigue fracture test at 43 N, fracture did not occur until $2{\times}10^6$ cycles at diameter 2.0 mm, and until $5{\times}10^6$ cycles at 2.5 mm and 3.0 mm. Conclusion: Compressive strength increased significantly with increasing diameter of mini implant. In the results of fatigue fracture test conducted under the average masticatory force of complete denture, fracture did not occur at any of the three diameters. All of the three diameters are usable for supporting overdenture in maxillary and mandibular edentulous patients, but considering that the highest masticatory force of complete denture is 157 N, caution should be used in case diameter 2.0 mm or 2.5 mm is used.

• The Journal of Korean Academy of Prosthodontics
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• v.52 no.2
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• pp.113-120
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• 2014

This study will evaluate the effectiveness of various pretreatments when fiber-reinforced composite (FRC) post is bonded to endodontically treated tooth with resin cement. Materials and methods: Canal shaping of FRC post (DT Light post, Size 3, Bisco Inc., Schaumburg, IL, USA) was performed on endodontically treated premolars at 1.5 cm from CEJ. Samples were divided into 6 groups of surface treatment after conventional washing and drying to the canal. Total of 24 FRC posts were randomly divided into 6 groups of surface treatment as follows: Group C: control - no surface treatment, Group A: airborne-particle abrasion (Cojet sand, 3M ESPE), Group S: silanization (Bis-silane, Bisco Inc.), Group M: universal primer (Monobond-plus primer, Ivoclar Vivadent Inc.), Group AS: silanization after airborne-particle abrasion, Group AM: universal primer treatment after airborne-particle abrasion. Pretreated fiber posts were cemented with resin-based luting material and photo-polymerized and cut to the thickness of 1 mm. Push-out test using a universal testing machine was performed. Bonding failure strength of post dislodgement was measured and the type of bonding failure was classified. Data were analyzed with Kruskal-Wallis test and multiple comparison groups were performed using Tukey HSD value of rank test (${\alpha}=0.05$). Results: Group AS showed significantly highest bonding strength. Group S, group AM, group A, and group M showed lower bonding strength in order. The control group showed the lowest bonding strength. Conclusion: Surface treatment with silane showed to be the most effective of the surface pretreatment methods for cementation of FRC post. Surface treatment with universal primer showed no significant difference compared with no surface treatment group as for bonding strength.

• Journal of the Korean Society of Food Science and Nutrition
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• v.41 no.2
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• pp.221-226
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• 2012

For the investigation of a possibility as a useful functional material, 6 cultivars (Takinosawa Gold, Kawanakawase Hakuto, Madoka, Yumefuji, Nagasawa Hakuho, Hong Bak) of Prunus persica L. Batsch were studied at unripe stage to determine the physicochemical properties and chemical compositions. The cultivars were picked in late May, and all samples were analyzed for external properties, physicochemical properties, pH, Brix value, Hunter's color value, hardness, vitamin C, and reducing sugar. The size of the fruit from all six cultivars was compared, and it was determined that cultivars, fruit from Madoka was the largest, while that from Yumefuji was the smallest. Comparing fresh weight, the fruit from Yumefuji was lowest in moisture contents (89.13~89.96%), and that from Nagasawa Hakuho had significantly higher crude protein (1.02~1.62%). The contents of crude lipids (0.18~0.23%) and carbohydrates (8.00~9.35%) were not significantly different between cultivars and Madoka included higher crude ash contents (0.32~0.69%) than other cultivars. The pH of 6 cultivars from unripe peaches were significantly higher from Kawanakawase Hakuto, and the Brix value was also highest from Kawanakawase Hakuto, followed by Yumefuji, Madoka, Nagasawa Hakuho, Takinosawa Gold, and Hong Bak. In chromaticity, the L value, the indicator of brightness, was significantly higher in fruit from Nagasawa Hakuho. The a value, the indicator of redness, was the highest with Hong Bak and overall lower than -5. The b value, the indicator of yellowness, was the highest in fruit from Madoka and ranged from 16.51 to 18.33. In physical characteristics, the hardness of the unripe peaches was the highest in fruit from Hong Bak, and overall, white peaches have a higher hardness value than yellow peaches. The vitamin C content of the fruit didn't show any significant differences between cultivars, and the reducing sugar showed a higher percent than 6.34% in fruit from all cultivars. These results suggest that unripe peaches were commensurate with the development of natural pigment and as a functional foods.

• Journal of the Korean Society of Food Science and Nutrition
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• v.37 no.9
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• pp.1154-1161
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• 2008

The purpose of this study is to determine the possibility of using Sophorae fructus as natural health food source. To accomplish this purpose, the contents of general and antioxidative nutrients of Sophora fructus were measured. The contents of carbohydrate, crude protein, crude lipid and ash are 75.9%, 16.4%, 2.41%, and 5.2%, respectively, while the calories of Sophora fructus was 337.3 kcal. Total dietary fiber was 15.07% of total carbohydrates. The percentages of water soluble dietary fiber to insoluble dietary fiber were 1.09% and 10.36%, respectively. The protein was composed of a total of 18 different kinds of amino acids. The contents of essential and non-essential amino acids were 2,310.91 mg and 5,218.52 mg. The K was the largest mineral followed by Ca, P and Mg, which means Sophorae fructus is alkali material. The contents of saturated fatty acids, monounsaturated fatty acids and polyunsaturated fatty acids were 24.94%, 32.40%, and 32.86%, respectively. Therefore, the amount of the total unsaturated fatty acid was higher than that of any other plant. The content of vitamin C in Sophorae fructus was higher than that of any other plant, which suggests that it could increase blood elasticity. The content of rutin, which is responsible for capillary vessel permeability, was 1.78%. The contents of water soluble antioxidative materials in 1 mL of water-extracted Sophorae fructus were $4.95\;{\mu}g$ which is comparable to 1,560.96 mmol of vitamin C in antioxidant effect. The general nutrients and other antioxidatant bioactive materials in Sophorae fructus were also potential materials for good health food. It is expected that a follow up study on Sophorae fructus through developing processed food and evaluation of their functional properties would provide useful information as a source of medicinal foods.

• Journal of Bio-Environment Control
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• v.19 no.1
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• pp.49-54
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• 2010

The study was conducted to compare the postharvest physiology and storability of fresh cut paprika fruits classified by normal, blossom end rot(BER), and misshapen (or knots) fruit. Some disordered paprika fruits that were produced frequently during high temperature season in highland, were sorted out to non-marketable products. These fruits are mostly wasted, but some of them may be used for fresh cut. The respiration rate of fresh cut paprika fruits was lower and ethylene production rate was higher in normal fruits than in disordered fruits, but there was no significant difference. The fresh-cut paprika fruits were stored in MAP conditions at $4^{\circ}C$, $9^{\circ}C$ and room temperature in 25 ${\mu}m$ and 50 ${\mu}m$ thickness ceramic film packaging. The fresh weight of fresh cut paprika fruits decreased below to 1.1% regardless of fruit types, but the fresh weight loss increased in thinner packaging materials and lower storage temperatures. There were not significant different carbon dioxide and oxygen contents in MAP of all fruit types, while $4^{\circ}C$ storage temperature treatment and 25 ${\mu}m$ thickness ceramic film treatment had lower carbon dioxide and higher oxygen contents. Moreover, the carbon dioxide and oxygen contents were changed rapidly at 9 days in $4^{\circ}C$ storage and at 6 days in $9^{\circ}C$ storage when the visual quality of fresh cut decreased dramatically. The ethylene concentration of packages was below 7 ${\mu}l{\cdot}l^{-1}$ in all treatments during storage, while the treatments of thinner packaging material and lower storage temperature showed lower ethylene concentration. The fresh cut of disordered fruits showed less visual quality than normal fruit treatment in both $4^{\circ}C$ and $9^{\circ}C$ storage temperatures, but there was no significant difference. The value of $4^{\circ}C$ treatment that measured 12 days in storage was higher than $9^{\circ}C$ treatment that measured 9 days in storage. The results suggest that the disordered fruits may be used to fresh cut product without any concerns that they will decreased the value of commodities more quickly than the fresh cut made of marketable paprika fruits. As the fresh cut paprika fruits stored in MAP condition, the more effective storage temperature is $4^{\circ}C$ that may have induced chilling injury a whole fruit of the paprika.

• Investigative Magnetic Resonance Imaging
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• v.4 no.1
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• pp.27-33
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• 2000

Purpose: To determine the electronic spin relaxation times, $T_{le}$, of three commercially available Gd-chelated MR contrast agents, Gd-DTPA, Gd-DTPA-BMA and Gd-DOTA, using Electron Paramagnetic Resonance(EPR) technique. Material and Methods: The paramagnetic MR contrast agents, Gd-DTFA(Magnevist) , Gd-DTFA-BMA(OMNISCAN) and Gd-DOTA(Dotarem), were used for this study, The EPR spectra of these contrast agents, which were prepared 2:1 methanol/water solution, were obtained at low temperatures, from $-160^{\circ}C~20^{\circ}C$. The glassy-state EPR spectra for these contrast agents were then fitted by the simulation spectra generated with different zero-field splitting (ZFS) parameters by a computer simulation program 'GEN', which generates the EPR powder spectrum using a given ZFS in $3{\times}3$ tensor. Finally, the spin relaxation times of the contrast agents were then determined from the $T_{2e}$, D, and E values of the best simulation spectra using the McLachlan's theory of average relaxation rate. Results: The electronic transverse spin relaxation times, $T_{2e}'s$, of Gd-DTPA, Gd-DTPA-BMA and Gd-DOTA were 0.113ns, 0.147ns and 1.81ns respectively. The g-values were 1.9737, 1.9735 and 1.9830 and the electronic spin relaxation times, $T_{1e}'s$, were 18.70ns, 33.40ns and $1.66{\mu}s$, respectively. Conclusion: The results of these studies reconfirm that the paramagnetic MR contrast agents with larger ZFS parameters should have shorter $T_{1e}'s$. Among three contrast agents used for this study, Gd-DOTA chelated with cyclic ligand structure shows better electronic property then the others with linear structure. Thus, it is concluded that the exact determination of ZFS parameters is the important factor in evaluating relaxation enhancement effect of the agents and in developing new contrast agents.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.7 no.3
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• pp.181-194
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• 2002

Parasitism is a one-sided relationship between two organisms in which one benefits at the expense of the other. Parasitic dinoflagellates, particularly species of Amoebophrya, have long been thought to be a potential biological agent for controlling harmful algal bloom(HAB). Amoebophrya infections have been reported for over 40 species representing more than 24 dinoflagellate genera including a few toxic species. Parasitic dinoflagellates Amoebophrya spp. have a relatively simple life cycle consisting of an infective dispersal stage (dinospore), an intracellular growth stage(trophont), and an extracellular reproductive stage(vermiform). Biology of dinospores such as infectivity, survival, and ability to successfully infect host cells differs among dinoflagellate host-parasite systems. There are growing reports that Amoebophrya spp.(previously, collectively known as Amoebophrya ceratii) exhibit the strong host specificity and would be a species complex composed of several host-specific taxa, based on the marked differences in host-parasite biology, cross infection, and molecular genetic data. Dinoflagellates become reproductively incompetent and are eventually killed by the parasite once infected. During the infection cycle of the parasite, the infected host exhibits ecophysiologically different patterns from those of uninfected host in various ways. Photosynthetic performance in autotrophic dinoflagellates can be significantly altered following infection by parasitic dinoflagellate Amoebophrya, with the magnitude of the effects over the infection cycle of the parasite depending on the site of infection. Parasitism by the parasitic dinoflagellate Amoebophrya could have significant impacts on host behavior such as diel vertical migration. Parasitic dinoflagellates may not only stimulate rapid cycling of dissolved organic materials and/or trace metals but also would repackage the relatively large sized host biomass into a number of smaller dinospores, thereby leading to better retention of host's material and energy within the microbial loop. To better understand the roles of parasites in plankton ecology and harmful algal dynamics, further research on a variety of dinoflagellate host-parasite systems is needed.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.10 no.1
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• pp.92-99
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• 2005

To discriminate the provenance of shelf sediments in the East China Sea, textural and elemental compositions along with strontium isotopic ratio ($^{87}Sr/^{86}Sr$) were analyzed and compared with the sediments originated from Chinese rivers. The sediments in the study area are composed of fine-grained mud with a mean grain size of $47\;{\phi}$ and their $CaCO_3$, contents range from 3.9 to 11.5% (average 7.6%). In the study area, the content of most metallic elements are strongly constrained by sediment grain size (quartz dilution effect) and that of biogenic material and, thereby, their spatial distribution seems not enough for understanding sediment provenance in the study area. The muddy sediments of the Yangtze river have much lower $^{87}Sr/^{86}Sr$ ratio ($0.71197{\sim}0.71720$) than the Yellow Sea shelf muddy sediments which are supposed to be originated from the Huanghe river ($0.72126{\sim}0.72498$), suggesting the distribution pattern of $^{87}Sr/^{86}Sr$ ratios as a new tracer to discriminate the provenance of shelf sediments in the study area. Different source rock compositions and weathering processes between both drainage basins may account for the differences in $^{87}Sr/^{86}Sr$ ratio. Although the ratios show wide range, from 0.71445 to 0.72184 with an average 0.71747 in the study area, they are close to the values of the Yangtze river sediments, suggesting that the sediments were mainly originated from the Yangtze river. The previous studies on the dispersal pattern of modern sediments and the physico-chemical properties of seawater in the Yellow and East China seas support the possibility that the fine-grained Yangtze river sediments can reach to the East China Sea shelf as well as to the southeastern Yellow Sea.

• Korean journal of food and cookery science
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• v.19 no.6
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• pp.685-693
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• 2003

The aim of this study was to develop a standardized recipe for black sesame gruel that has been preferred for generations as a nutritional food. The method focused on optimizing the mixing ratio of the components to improve the quality of the black sesame gruels that modem consumers would like. The results are summarized as follows: The more black sesame added to the gruel, the lower its brightness was, but the redness and yellowness was higher. The amount of black sesame made a significant difference in the viscosity, color, nutty taste, bitterness, appearance and overall preference. It was highest in the overall preference when the amount of black sesame was added 33g(40％ of rice weight basis). Different types of rice were added to the black sesame gruel, and it was observed that the color value of the gruel was high in its brightness, redness and yellowness when 50g(60％) of glutinous rice was added to it. The black sesame gruel was most preferred when 50g of non-glutinous rice was added. The redness value was high when 15g(18％) of non-glutinous rice flour was added. The yellowness value was high when 25g(30％) of non-glutinous rice flour was added. This observation showed significant differences in the viscosity, color, nutty taste, bitterness, appearance and overall preference. In particular, the black sesame gruel was most preferred when 50g of non-glutinous rice flour was added. The addition of 7g(9％) of salt to the black sesame gruel showed the highest brightness. The redness and yellowness was the highest when 5g(6％) of salt was added. This observation showed a significant difference in the viscosity, color, nutty taste, bitterness, appearance and overall preference. The highest preference was observed when 2.5g(3％) of salt was added. Adding more materials increased the viscosity of the black sesame gruel. With increasing temperature, the viscosity became lower, and vice versa. The intensity of sweetness and spreadability was found to be proportional to the amount of additive material. In conclusion, the optimum recipe for black sesame gruels was obtained 33g(40％) of black sesame, 50g(60％) of glutinous rice (flour), 2.5g of salt, and 500$m\ell$ of water.